HIGH-PRESSURE PUMP

Abstract

High-pressure pump (10), comprising: a pressurization chamber formation section (23) which defines a pressurization chamber (200) in which fuel is pressurized; a discharge passage formation section (21) defining a discharge passage (217) through which the fuel flows which is discharged from the pressurization chamber (200); a discharge seat element (71) arranged in the discharge passage (217), wherein the discharge seat element (71) comprises the following: a discharge hole (73) passing through the discharge seat element (71) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); and a discharge valve seat (74) located around the discharge hole (73) on the other surface of the discharge seat element (71), which is arranged facing away from the pressurization chamber (200); an intermediate element (81) arranged on one side of the discharge seat element (71) opposite the pressurization chamber (200), wherein the intermediate element (81) includes a first passage (83) passing through the intermediate element (81) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); an overflow seat element (85) arranged on one side of the intermediate element (81) opposite the pressurization chamber (200), wherein the overflow seat element (85) comprises the following: an overflow hole (87) passing through the overflow seat element (85) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); an overflow valve seat (88) is located around the overflow hole (87) on one surface of the overflow seat element (85) that faces the pressurization chamber (200); and a second passage (89) through the overflow seat element (85) between one surface which is arranged facing the pressurization chamber (200) and the other surface which is arranged away from the pressurization chamber (200); a drain valve (75) arranged between the intermediate element (81) and the drain seat element (71), wherein the drain valve (75) is able to allow fuel flow through the drain hole (73) by separating from the drain valve seat (74) to open the drain hole (73), and to restrict fuel flow through the drain hole (73) by contacting the drain valve seat (74) to close the drain hole (73); and a bypass valve (91) arranged between the intermediate element (81) and the bypass seat element (85), wherein the bypass valve (91) is able to allow fuel flow through the bypass hole (87) by separating from the bypass valve seat (88) to open the bypass hole (87), and to restrict fuel flow through the bypass hole (87) by contacting the bypass valve seat (88) to close the bypass hole (87), wherein at least one selected from the intermediate element (81) and the overflow seat element (85) includes an annular recess (800) which has an annular shape and fluidly connects the first passage (83) and the second passage (89), and the annular recess (800) is recessed starting from a surface of the at least one selected from the intermediate element (81) and the overflow seat element (85), which are arranged facing each other, wherein the annular recess (800) is arranged between the first passage (83) and the second passage (89) and is in direct fluid communication with both the first passage (83) and the second passage (89).

Description

Cross-reference to similar registration

[0001] This application is based on Japanese patent application no. 2017-190 632, filed on September 29, 2017, and on Japanese patent application no. 2018-176 427, filed on September 20, 2018. Technical field

[0002] The present disclosure relates to a high-pressure pump. State of the art

[0003] A high-pressure pump, conventionally known as a pump for pressurizing and supplying fuel to an internal combustion engine, includes a bypass valve for releasing fuel to a pressurized or low-pressure chamber when the pressure of the fuel discharged from the pressurized chamber reaches a predetermined value or higher. According to a high-pressure pump described in patent literature 1, for example, a bypass valve is configured to release fuel to a low-pressure chamber. Literature on the state of the art Patent literature

[0004] Patent Literature 1: JP 2004-197 834 A

[0005] Further state of the art is disclosed in the following documents.

[0006] JP 2004-197 834 A discloses the following: A pressure pulsation reduction mechanism for reducing pressure pulsation is attached to the upstream side of the pressure relief valve, and the pulsation reduction mechanism consists of a receiving element with a channel and a gap element located in the channel of the receiving element to form a gap flow. The gap for forming the gap flow can be formed between the receiving element and the gap element or on the gap element itself. Furthermore, the pressure pulsation reduction mechanism can include the receiving element with the channel and a shielding element mounted on the receiving element to shield the channel and block the direct flow of the fluid.

[0007] US 2015 / 0078922A1 discloses the following: A high-pressure pump comprises a pump body, a pressure chamber, a fuel channel, a connector, a seat, a pressure relief valve seat, a pressure relief valve, an outlet valve seat, an outlet valve, a spring, and a spring retainer. The connector has an internally threaded section and a stepped section formed on an inner wall of the connector. The seat comprises a relief passage extending through the seat in an axial direction and an outlet passage that is not in fluid communication with the relief passage. One opening of the relief passage is closer to the pressure chamber than another opening of the relief passage is to the pressure chamber. One opening of the relief passage is farther from the pressure chamber than another opening of the relief passage is to the pressure chamber.The seat element is pressed towards the step section when the spring holder is attached to the connection by engaging the internal threaded section with the external threaded section. Summary

[0008] Recently, the need for higher fuel pressure in a machine system has led to a need for a higher-pressure fuel supply to an internal combustion engine. To increase the pressure of the fuel being discharged from and supplied to the internal combustion engine by the high-pressure pump, it is effective to reduce the dead volume associated with the pressurization chamber and to create a high-pressure space during pressurization. According to the high-pressure pump described in patent literature 1, a discharge valve is located near the pressurization chamber, while the overflow valve is located on the side opposite the pressurization chamber. This configuration can reduce the dead volume.

[0009] According to the high-pressure pump described in patent literature 1, the overflow valve is arranged at a position that is radially offset from the axis of the discharge valve, and a pressure pulsation reduction device is provided between the discharge valve and the overflow valve. Furthermore, a flow path through which the discharged fuel flows after passing through the discharge valve is formed radially outside the overflow valve and the pressure pulsation reduction device. Accordingly, the size of the section containing the discharge valve and the overflow valve can be increased.

[0010] It is an object of the present disclosure to provide a small high-pressure pump. This object is achieved by the high-pressure pump with the features of claim 1. Further advantageous embodiments and developments are the subject of the subsequent claims.

[0011] <c>A high-pressure pump according to this disclosure comprises a pressurization chamber forming section, a discharge passage forming section, a discharge seat element, an intermediate element, a bypass seat element, a discharge valve, and a bypass valve. The pressurization chamber forming section defines a pressurization chamber in which fuel is pressurized. The discharge passage forming section defines a discharge passage through which the fuel flows that is discharged from the pressurization chamber.The discharge seat element comprises a discharge element body arranged in the discharge passage, a discharge hole passing through the discharge seat element between a surface of the discharge seat element facing the pressurization chamber and a surface of the discharge seat element facing away from the pressurization chamber, and a discharge valve seat located around the discharge valve hole on the surface facing the pressurization chamber.

[0012] The intermediate element is arranged on one side of the discharge seat element opposite the pressurization chamber and includes a first passage through the intermediate element between a surface of the intermediate element facing the pressurization chamber and a surface of the intermediate element facing away from the pressurization chamber.The overflow seat element is arranged on one side of the intermediate element opposite the pressurization chamber and includes an overflow hole passing through the overflow seat element between a surface of the overflow seat element facing the pressurization chamber and a surface of the overflow seat element facing away from the pressurization chamber, an overflow valve located around the overflow hole on the surface facing the pressurization chamber, and a second passage passing through the overflow seat element between the surface of the overflow seat element facing the pressurization chamber and the surface of the overflow seat element facing away from the pressurization chamber.

[0013] The discharge valve is arranged between the discharge seat element and the intermediate element and is capable of allowing fuel to flow into the discharge port by separating from the discharge valve seat to open the discharge port, and of restricting fuel flow into the discharge port by contacting the discharge valve seat to close the discharge valve seat. At least one of the intermediate element and the transfer seat element includes an annular recess that has a ring shape and fluidly connects the first and second ports.The annular recess is formed from a surface of at least one of the intermediate element and the overflow seat element, which are arranged facing each other. The annular recess is located between the first and second passages and is in direct fluid communication with both. In this disclosure, the discharge valve and the overflow valve are arranged coaxially and integrally within a confined space. This reduces the size of the section containing the discharge valve and the overflow valve, and consequently, the high-pressure pump is also reduced in size. Brief description of the drawings

[0014] These and other tasks, features and advantages of the present disclosure will become clear from the following detailed description with reference to the accompanying drawings. Fig. 1 a schematic diagram showing a fuel supply system to which a high-pressure pump according to a first embodiment is applied; Fig. 2 a cross-sectional view of the high-pressure pump according to the first embodiment; Fig. 3 a cross-sectional view of the high-pressure pump according to the first embodiment; Fig. 4 a cross-sectional view, wherein the cross-section is shown along a line IV-IV in Fig. 2 has been carried out; Fig. 5 a cross-sectional view showing an intake valve unit and an electromagnetic drive unit of the high-pressure pump according to the first embodiment; Fig. 6 a cross-sectional view showing a discharge passage section of the high-pressure pump according to the first embodiment; Fig. 7 a front view of a cylinder of the high-pressure pump according to the first embodiment; Fig. 8 a view of Fig. 7, as viewed in one direction of arrow VIII; Fig. 9 a cross-sectional view of the cylinder of the high-pressure pump according to the first embodiment; Fig. 10 an enlarged cross-sectional view of the intake valve unit of the high-pressure pump according to the first embodiment; Fig. 11 a schematic view of a seat element of the high-pressure pump according to the first embodiment; Fig. 12 a schematic view of a stopper of the high-pressure pump according to the first embodiment; Fig. 13 a schematic view of a valve element of the high-pressure pump according to the first embodiment, as viewed from the pressurization chamber; Fig. 14 a schematic view of the valve element of the high-pressure pump according to the first embodiment, as viewed from the seat element; Fig. 15 a cross-sectional view, wherein the cross-section is shown along a line XV-XV in Fig. 13 has been undertaken; Fig. 16 a view of Fig. 13, as viewed in the direction of arrow XVI; Fig. 17 a graph showing a relationship between a plate thickness ratio t / D of the valve element of the high pressure pump according to the first embodiment, a sealing surface pressure and a limiting pressure; Fig. 18 a cross-sectional view, wherein the cross-section is shown along a line XVIII-XVIII in Fig. 5 has been carried out; Fig. 19 a schematic cross-sectional view of a coil of the high-pressure pump according to the first embodiment; Fig. 20 a schematic cross-sectional view of a coil according to a first comparative example; Fig. 21 a schematic cross-sectional view of a coil according to a second comparative example; Fig. 22 a view of the coil of the high-pressure pump according to the first embodiment; Fig. 23 a view of Fig. 22, as viewed in the direction of arrow XXIII; Fig. 24 a development view and a sectional view of an outer peripheral wall of a winding formation section of the high pressure pump according to the first embodiment; Fig. 25 a cross-sectional view of a discharge port of the high-pressure pump according to the first embodiment; Fig. 26 a view of Fig. 25, as viewed in the direction of arrow XXVI; Fig. 27 a view of Fig. 25, as viewed in the direction of arrow XXVII; Fig. 28 a cross-sectional view of a discharge seat element of the high-pressure pump according to the first embodiment; Fig. 29 a view of Fig. 28, as viewed in the direction of arrow XXIX; Fig. 30 a view of Fig. 28, as viewed in the direction of an arrow XXX; Fig. 31 a cross-sectional view of an intermediate element of the high-pressure pump according to the first embodiment; Fig. 32 a view of Fig. 31, as viewed in the direction of arrow XXXII; Fig. 33 a view of Fig. 31, as viewed in the direction of arrow XXXIII; Fig. 34 a cross-sectional view of an overflow seat element of the high-pressure pump according to the first embodiment; Fig. 35 a view of Fig. 34, as viewed in the direction of arrow XXXV; Fig. 36 a view of Fig. 34, as viewed in the direction of arrow XXXVI; Fig. 37 a cross-sectional view of a discharge valve of the high-pressure pump according to the first embodiment; Fig. 38 a view of Fig. 37, as viewed in the direction of arrow XXXVIII; Fig. 39 a view of Fig. 37, as viewed in the direction of arrow XXXIX; Fig. 40 a view of an overflow valve of the high-pressure pump according to the first embodiment; Fig. 41 a view of Fig. 40, as viewed in the direction of arrow XLI; Fig. 42 a view of Fig. 40, as viewed in one direction of arrow XLII; Fig. 43 a view of a spring that biases the discharge valve of the high pressure pump according to the first embodiment; Fig. 44 a view of Fig. 43, as viewed in the direction of arrow XLIV; Fig. 45 a view of a spring that biases the overflow valve of the high-pressure pump according to the first embodiment; Fig. 46 a view of Fig. 45, as viewed in the direction of arrow XLVI; Fig. 47 a schematic view of a valve element of a high-pressure pump according to a second embodiment, as viewed from the pressurization chamber; Fig. 48 a schematic view of the valve element of the high pressure pump according to the second embodiment, as viewed from the seat element; Fig. 49 a schematic view of a valve element of a high-pressure pump according to a third embodiment, as viewed from the pressurization chamber; Fig. 50 a schematic view of the valve element of the high pressure pump according to the third embodiment, as viewed from the seat element; Fig. 51 a schematic view of a valve element of a high-pressure pump according to a fourth embodiment, as viewed from the pressurization chamber; Fig. 52 a schematic view of the valve element of the high pressure pump according to the fourth embodiment, as viewed from the seat element; Fig. 53 a cross-sectional view of a discharge passage section of a high-pressure pump according to a fifth embodiment; Fig. 54 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to a sixth embodiment; Fig. 55 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to a seventh embodiment; Fig. 56 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to an eighth embodiment; Fig. 57 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to a ninth embodiment; Fig. 58 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to a tenth embodiment; Fig. 59 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to an eleventh embodiment; Fig. 60 a front view of a cylinder of a high-pressure pump according to a twelfth embodiment; Fig. 61 a view of Fig. 60, as viewed in one direction of arrow LXI; Fig. 62 an enlarged cross-sectional view of an intake valve unit of a high-pressure pump according to a thirteenth embodiment; Fig. 63 a schematic view of a stopper of a high-pressure pump according to a fourteenth embodiment; Fig. 64 a cross-sectional view of an intake valve unit and an electromagnetic drive unit of a high-pressure pump according to a fifteenth embodiment; Fig. 65 a cross-sectional view of an intake valve unit and an electromagnetic drive unit of a high-pressure pump according to a sixteenth embodiment; Fig. 66 a cross-sectional view of an intake valve unit and an electromagnetic drive unit of a high-pressure pump according to a seventeenth embodiment; Fig. 67 a cross-sectional view of an intake valve unit and an electromagnetic drive unit of a high-pressure pump according to an eighteenth embodiment; Fig. 68 a cross-sectional view of a discharge passage section of a high-pressure pump according to a nineteenth embodiment; Fig. 69 a cross-sectional view of a high-pressure pump according to a twentieth embodiment; Fig. 70 a front view of a cylinder of the high-pressure pump according to the twentieth embodiment; Fig. 71 a view of Fig. 70, as viewed in the direction of arrow LXXI; Fig. 72 a cross-sectional view, wherein the cross-section is shown along a line LXXII-LXXII in Fig. 69 was undertaken; Fig. 73 a cross-sectional view of a high-pressure pump according to a comparative example; Fig. 74 a cross-sectional view of a high-pressure pump according to a twenty-first embodiment; Fig. 75 a cross-sectional view of a high-pressure pump according to a twenty-second embodiment; Fig. 76 a cross-sectional view of a high-pressure pump according to a twenty-third embodiment; Fig. 77 a cross-sectional view of a high-pressure pump according to a twenty-fourth embodiment; Fig. 78 a cross-sectional view of a high-pressure pump according to a twenty-fifth embodiment; Fig. 79 a cross-sectional view of a high-pressure pump according to a twenty-sixth embodiment; Fig. 80 a cross-sectional view of a high-pressure pump according to a twenty-seventh embodiment; Fig. 81 a cross-sectional view of a high-pressure pump according to a twenty-eighth embodiment; Fig. 82 a cross-sectional view, wherein the cross-section is shown along a line LXXXII-LXXXII in Fig. 81 has been carried out; Fig. 83 a cross-sectional view of a high-pressure pump according to a twenty-ninth embodiment; Fig. 84 a cross-sectional view of a high-pressure pump according to a thirtieth embodiment; Fig. 85 a front view of a cylinder of a high-pressure pump according to a thirty-first embodiment; Fig. 86 a view of Fig. 85, as viewed in the direction of arrow LXXXVI; Fig. 87 a cross-sectional view of a high-pressure pump according to a thirty-second embodiment; Fig. 88 a cross-sectional view of a high-pressure pump according to a thirty-third embodiment; Fig. 89 a cross-sectional view of a supply passage section of the high-pressure pump according to a thirty-fourth embodiment; and Fig. 90 a view of Fig. 89, as viewed in the direction of an arrow XC; Description of the embodiments

[0015] A high-pressure pump according to the embodiments is described below with reference to the drawings. In the embodiments, essentially identical components are designated with identical reference numerals and are not explained again. Furthermore, in the embodiments, essentially identical components offer identical or similar effects. First embodiment

[0016] The Fig. 1 and Fig. Figure 2 shows a high-pressure pump according to a first embodiment.

[0017] In the present embodiment, the high-pressure pump 10 is applied to a fuel supply system 9, which includes fuel injectors 138 for supplying fuel to an internal combustion engine (not shown in detail). Hereinafter, the internal combustion engine is referred to as the "engine". The high-pressure pump 10 is mounted on an engine head 2 of the engine 1 or on a housing that is movable or can be moved by the crankshaft.

[0018] As in Fig. As shown in Figure 1, gasoline or the like is stored as fuel in a fuel tank 132, which is installed in the vehicle. A fuel pump 133 pumps the fuel up from the fuel tank 132 and discharges it. A supply fuel pipe 7 connects the fuel pump 133 and the high-pressure pump 10 fluidically. Accordingly, the fuel that is pumped up and discharged by the fuel pump 133 flows through the supply fuel pipe 7 into the high-pressure pump 10.

[0019] Machine 1 includes a fuel distributor 137 and a high-pressure pump 10. Machine 1 is, for example, a four-cylinder gasoline engine. The fuel distributor 137 is located on the engine head 2 of machine 1. The fuel injectors 138 are arranged such that one injection port of each fuel injector 138 is exposed to the interior of a combustion chamber of machine 1. The four fuel injectors 138 are, for example, numbered according to the number of cylinders of machine 1. The four fuel injectors 138 are fluidly connected to the fuel distributor 137.

[0020] The high-pressure pump 10 and the fuel distributor 137 are connected by a high-pressure fuel line 8. Fuel flowing from the supply fuel line 7 into the high-pressure pump 10 is pressurized by the high-pressure pump 10 and supplied to the fuel distributor 137 via the high-pressure fuel line 8. In this way, the fuel in the fuel distributor 137 is maintained at a relatively high pressure. Each of the fuel injectors 138 opens and closes in response to a command from an electronic control unit (ECU), which acts as a controller, and injects fuel from the fuel distributor 137 into the combustion chamber of the engine 1. The ECU is not shown or detailed in the drawings. Accordingly, the fuel injectors 138 are so-called direct injection (DI) fuel injectors.

[0021] A sensor 130 is provided between the high-pressure pump 10 of the fuel supply line 7 and the fuel tank 132. The sensor 130 is capable of detecting the fuel pressure and temperature in the fuel supply line 7 and transmitting corresponding signals to the ECU. Based on the fuel pressure and temperature in the fuel supply line 7 detected by the sensor 130, the ECU determines the target fuel pressure to be delivered by the fuel pump 133. The ECU then controls the operation of the fuel pump 133 motor to deliver fuel at the target pressure from the fuel pump 133.

[0022] As in Fig. As shown in Figure 2, the high-pressure pump 10 includes an upper housing 21, a lower housing 22, a fixed section 25, a cylinder 23, a holder support 24, a cover 26, a plunger 11, an intake valve unit 300, an electromagnetic drive unit 500, a discharge passage section 700, and other components.

[0023] The upper housing 21, the lower housing 22, the fixed section 25, the cylinder 23, and the support bracket 24 are all made of metal, such as stainless steel. The upper housing 21 and the lower housing 22 together form a single “housing”.

[0024] The upper housing 21 has a substantially octagonal column shape. The upper housing 21 includes an outer peripheral wall 270 of the housing, which has an octagonal column shape. The outer peripheral wall 270 of the housing has flat sections 271, each of which has a flat shape. The eight flat sections 271 are formed in a circumferential direction of the outer peripheral wall 270 of the housing (compare Fig. 4).

[0025] The upper housing 21 includes a hole section 211, an intake hole section 212, an intake hole section 213, an exhaust hole section 214, and an exhaust hole section 215. The hole section 211 has a cylindrical shape and passes along an axis of the upper housing 21 through a center point of the upper housing 21.

[0026] The intake port section 212 has a substantially cylindrical shape extending from one of the flat sections 271 of the outer peripheral wall 270 of the housing of the upper housing 21 to the port section 211. The intake port section 213 has a substantially cylindrical shape and is connected to the intake port section 212 and the port section 211. The intake port section 212 and the intake port section 213 are coaxial. Each of the axes of the intake port section 212 and the intake port section 213 is orthogonal to the axis of the port section 211. The inner diameter of the intake port section 213 is smaller than the inner diameter of the intake port section 212 (compare Fig. 5) An intake passage 216 is defined by the intake hole section 212 and the intake hole section 213 of the upper housing 21. The upper housing 21 corresponds to an “intake passage formation section”.

[0027] The discharge port section 214 has a substantially cylindrical shape, extending from the flat section 271, which is located opposite the flat section 271 of the outer peripheral wall 270 of the housing of the upper housing 21, on which the intake port section 212 is formed, to the port section 211. The discharge port section 215 has a substantially cylindrical shape and is connected to the discharge port section 214 and the port section 211. The discharge port section 214 and the discharge port section 215 are coaxial. Each of the axes of the discharge port section 214 and the discharge port section 215 is orthogonal to the axis of the port section 211. The inner diameter of the discharge port section 215 is smaller than the inner diameter of the discharge port section 214 (compare Fig. 6) A discharge passage 217 is defined by the discharge hole section 214 and the discharge hole section 215. The discharge hole section 214 and the discharge hole section 215 of the upper housing 21 correspond to a "discharge passage formation section". The discharge hole section 215 is smaller than a discharge hole 233. The central axis of the discharge hole section 215 is located below the central axis of the discharge hole 233 in the vertical direction.

[0028] The intake port section 212 and the intake port section 213, as well as the exhaust port section 214 and the exhaust port section 215, are coaxial. In other words, the respective axes of the intake port section 212, the intake port section 213, the exhaust port section 214, and the exhaust port section 215 are located on a common plane (compare the Fig. 2 to 4).

[0029] The upper housing 21 includes a housing recess 210 on a lower part of the upper housing 21. The housing recess 210 extends axially from an end surface of the upper housing 21. The housing recess 210 has a substantially cylindrical shape.

[0030] The lower housing 22 is essentially disc-shaped. The lower housing 22 has a hole section 221 and a hole section 222. The lower housing 22 includes a housing projection 220 on an upper part of the lower housing 22. The housing projection 220 extends from the center point of a surface of the lower housing 22. The housing projection 220 is essentially cylindrical.

[0031] The hole section 221 passes through the centers of the lower housing 22 and the housing projection 220 in a plate thickness direction of the lower housing 22. The inner diameter of the hole section 221 is slightly larger than the inner diameter of the hole section 211. The hole section 222 is formed radially outside the hole section 221 to pass through the lower housing 22 between an outer surface of the lower housing 22 radially outside the housing projection 220 and an inner surface of the lower housing 22.

[0032] The lower housing 22 is integrally formed with the upper housing 21 such that the housing projection 220 fits into the housing recess 210. The outer diameter of the housing projection 220 is larger than the inner diameter of the housing recess 210. Accordingly, the upper housing 21 and the lower housing 22 are fixed by an interference fit of the housing projection 220 into the housing recess 210. A surface of the upper housing 21, which faces the lower housing 22 in the axial direction, and a surface of the lower housing 22, which faces the upper housing 21 in the axial direction, are in contact with each other. A contact surface between the lower housing 22 and the upper housing 21 is referred to as a contact section 203, which is located in Fig. 2 is shown.

[0033] The upper housing 21 includes a bypass section 218 at an outer edge of the surface facing the lower housing 22, so as not to obstruct an opening of the hole section 222, which is also facing the upper housing 21. The bypass section 218 has a tapered surface to accommodate both the contact section 203 and the communication path between the bypass section 218 and the hole section 222.

[0034] The fixed section 25 has a plate shape that extends radially outward from the outer edge of the lower housing 22. The fixed section 25 is integrally formed with the lower housing 22. In other words, the fixed section 25 is connected to both the lower housing 22 and the upper housing 21. According to the present embodiment, the fixed section 25 is one of a plurality of fixed sections, and the plurality of fixed sections 25 consists of two fixed sections 25. The two fixed sections 25 are located at equal intervals from each other in a circumferential direction of the lower housing 22. Each of the two fixed sections 25 has a bolt hole 250. The bolt hole 250 has a substantially cylindrical shape that passes through the fixed section 25 in the plate thickness direction of the fixed section.

[0035] When the high-pressure pump 10 is attached to the machine 1, the fixed sections 25 are fastened to the machine head 2 of the machine 1 by bolts 100, which are provided in accordance with the bolt holes 250 (compare Fig. 2) Each of the bolts 100 has a shaft section 101 and a head section 102. The shaft section 101 is essentially column-shaped. The outer diameter of the shaft section 101 is slightly smaller than the inner diameter of each of the bolt holes 250.

[0036] The head section 102 is integrally formed with the shaft section 101 such that the head section is connected to one end of the shaft section 101. The outer diameter of the head section 102 is larger than the outer diameter of the shaft section 101. When the high-pressure pump 10 is mounted on the machine 1, the shaft section 101 of each bolt 100 is inserted into one of the bolt holes 250 of the fixed section 25 and screwed to a fixing hole section 120 of the machine head 2. During tightening, an axial force acts on the fixed section 25, originating from the head section 102 of the bolt 100 and extending towards the machine head 2. In this case, a suitable flatness is ensured at least around the head section 102 of the bolt 100 to bring the lower housing 22 into close contact with the machine head 2 when the bolts 100 are tightened.

[0037] The cylinder 23 has a cylindrical bore section 231. The cylindrical bore section 231 has a substantially cylindrical shape, extending from one end surface of the cylindrical element to the other end surface of the cylindrical element. In other words, the cylinder 23 has a bottomed cylindrical shape, comprising a cylindrical section and a bottom section that closes one end of the cylindrical section. A cylindrical inner peripheral wall 230, forming an inner peripheral wall of the cylindrical bore section 231, has a substantially cylindrical shape. The cylindrical inner peripheral wall 230 has a sliding surface 230a, a surface 230b with an enlarged diameter, and other features. The sliding surface 230a has a cylindrical shape and is located adjacent to an opening in the cylindrical inner peripheral wall 230.The surface 230b with the enlarged diameter has a cylindrical shape and is located on one side of the sliding surface opposite the opening of the cylindrical inner peripheral wall 230. The sliding surface 230a and the surface 230b with the enlarged diameter are coaxial. The diameter of the surface 230b with the enlarged diameter is larger than the diameter of the sliding surface 230a.

[0038] The outer diameter of the cylinder 23 is slightly larger than the inner diameter of the bore section 211 of the upper housing 21. The cylinder 23 is integrally formed with the upper housing 21 and the lower housing 22 such that the cylinder 23 is inserted into the bore section 221 of the lower housing 22, and an outer circumferential wall of the cylinder, facing the bottom section, is fitted into the bore section 221 of the upper housing 21. The cylinder 23 has an intake port 232 and an exhaust port 233. The intake port 232 connects the enlarged diameter surface 230b at one end of the cylinder bore section 231, which is located facing the bottom section, and the intake port section 213 of the upper housing 21. The exhaust port 233 connects the enlarged diameter surface 230b at the end of the cylinder bore section 231, which is located facing the bottom section, and the exhaust port section 215 of the upper housing 21.In other words, the intake port 232 and the exhaust port 233 are arranged facing each other relative to an axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder bore section 231, which is inserted between the intake port 232 and the exhaust port 233. Accordingly, the intake port 232 and the exhaust port 233 are arranged on a common plane (compare the . Fig. 2 to 4).

[0039] The support bracket 24 extends from a radially outer section or outer section of the hole section 221 of the lower housing 22 away from the upper housing 21. According to the present embodiment, the support bracket 24 is integrally formed with the lower housing 22. The support bracket 24 is coaxial with the cylinder 23 at the radially outer side of one end of the cylinder 23. When the high-pressure pump 10 is mounted on the machine 1, the support bracket 24 is inserted into a mounting hole section 3 formed on the machine head 2 (see Figure 1). Fig. 2).

[0040] The plunger 11 has a substantially cylindrical shape and is made of metal, such as stainless steel. The plunger 11 comprises a large-diameter section 111 and a small-diameter section 112. The outer diameter of the small-diameter section 112 is smaller than the outer diameter of the large-diameter section 111. The large-diameter section 111 of the plunger 11 is inserted into the cylinder bore section 231 of the cylinder 23. A pressurization chamber 200 is formed between a bottom wall of the cylinder bore section 231 and the surface 230b with the enlarged diameter of the cylindrical inner peripheral wall 230, and an end of the plunger 11 facing the large-diameter section 111. Accordingly, the cylinder 23 forms the pressurization chamber 200.Cylinder 23 has a cylindrical inner peripheral wall 230, which has a cylindrical shape and forms the pressurization chamber 200. Cylinder 23 corresponds to a "pressurization chamber formation section". The pressurization chamber 200 is connected to the intake port 232 and the exhaust port 233.

[0041] The outer diameter of the plunger 11 is slightly smaller than the inner diameter of the cylinder 23, i.e., the inner diameter of the cylinder bore section 231. Accordingly, it is possible for the plunger 11 to move back and forth in the axial direction within the cylinder bore section 231 with a large-diameter outer peripheral wall of the section 111 sliding on the sliding surface 230a of the cylindrical inner peripheral wall 230 of the cylinder bore section 231.

[0042] When the plunger 11 moves back and forth in the cylinder bore section 231, the volume of the pressurization chamber 200 increases or decreases. In this way, the plunger 11 has an end that is located in the pressurization chamber and is movable in the axial direction in the cylindrical inner peripheral wall 230.

[0043] According to the present embodiment, a seal holder 14 is provided in the holder support 24. The seal holder 14 has a tubular shape and is made of metal, such as stainless steel. The seal holder 14 is configured such that an outer wall of the seal holder 14 fits into an inner wall of the holder support 24. A column-shaped intermediate element 241 is provided between the cylinder 23 and the seal holder 14. The column-shaped intermediate element 241 has a substantially cylindrical shape and is coaxial with the cylinder 23. An inner diameter of the column-shaped intermediate element 241 is larger than an inner diameter of the cylinder bore section 231. The column-shaped intermediate element 241 has bore sections 242 that connect the inner peripheral wall and the outer peripheral wall of the column-shaped intermediate element 241.A majority of the hole sections 242 are formed in the circumferential direction of the column-shaped intermediate element 241.

[0044] The seal holder 14 defines a substantially cylindrical space enclosed by an inner wall of the seal holder 14, the end surface of the column-shaped intermediate element 241 facing away from the cylinder 23, and the outer peripheral wall of the small-diameter section 112 of the tappet 11. An annular seal 141 is provided within the cylindrical space. The seal 141 consists of a ring made of fluoropolymer and a ring made of rubber. The fluoropolymer ring is located radially inside the rubber ring. The thickness of a fuel-oil film on the tappet 11 around the small-diameter section 112 is controlled by the seal 141 to reduce fuel leakage to the machine 1. An oil seal 142 is provided at the end of the seal holder 14 facing away from the cylinder 23.

[0045] The oil seal 142 controls the thickness of an oil film on the tappet 11 around the small-diameter section 112 to reduce oil leakage. A variable-volume chamber 201, whose volume varies during a reciprocating movement of the tappet 11, is formed between a stepped surface between the large-diameter section 111 and the small-diameter section 112 of the tappet 11, as well as between the column-shaped intermediate element 241 and the seal 141.

[0046] An annular space 202, which is a ring-shaped space, is defined by outer peripheral walls of the lower housing 22 and the cylinder 23, an inner peripheral wall of the holder support 24, and the seal holder 14. The annular space 202 is connected to the hole section 222 of the lower housing 22. The annular space 202 is connected to the variable-volume chamber 201 via a cylindrical space defined by an inner peripheral wall of the seal holder 14, an outer peripheral wall of the cylinder 23, an outer peripheral wall of the column-shaped intermediate element 241, and the hole section 242.

[0047] A substantially disc-shaped spring seat 12 is provided at the end of the small-diameter section 112 of the plunger 11, which is located away from the large-diameter section 111. A spring 13 is provided between the seal holder 14 and the spring seat 12. The spring 13 is, for example, a coil spring and is configured such that one end of the spring 13 contacts the spring seat 12 and the other end of the spring 13 contacts the seal holder 14 via a spacer 140. The seal holder 14 is made of a weldable material and thus has a relatively low degree of hardness. Therefore, wear of the seal holder 14 is prevented by providing the spacer 140 with a relatively high degree of hardness. The spring 13 biases the plunger 11 away from the pressurization chamber 200 via the spring seat 12.When the high-pressure pump 10 is attached to the machine head 2 of the machine 1, a lifter 5 is attached to the end of the small-diameter section 112 of the plunger 11, which is arranged facing away from the large-diameter section 111.

[0048] When the high-pressure pump 10 is attached to the machine 1, the lifter 5 comes into contact with a cam 4 of a camshaft, which rotates in accordance with a drive shaft of the machine 1. As a result, the plunger 11 moves back and forth in accordance with the rotation of the cam 4 during rotation of the machine 1 in the axial direction. During this time, the volume of both the pressurizing chamber 200 and the variable-volume chamber 201 vary periodically.

[0049] As in Fig. As shown in Figure 2, when the plunger 11 is at bottom dead center, the end of the outer peripheral wall of the large-diameter section 111 of the plunger 11, which faces away from the small-diameter section 112, is located between the enlarged-diameter surface 230b and the end of the sliding surface 230a, which faces the enlarged-diameter surface 230b. At this time, the end of the outer peripheral wall of the large-diameter section 111 of the plunger 11, which faces the small-diameter section 112, is on one side of the end of the sliding surface 230a, which faces away from the enlarged-diameter surface 230b, opposite the enlarged-diameter surface 230b.

[0050] As in Fig. As shown in Figure 3, when the plunger 11 is at top dead center, the end of the outer peripheral wall of the large-diameter section 111 of the plunger 11, which is located away from the small-diameter section 112, is situated between the enlarged-diameter surface 230b and the end of the sliding surface 230a, which is located towards the enlarged-diameter surface 230b. At this time, the end of the outer peripheral wall of the large-diameter section 111 of the plunger 11, which is located towards the small-diameter section 112, is located on one side of the end of the sliding surface 230a, which is located away from the enlarged-diameter surface 230b, opposite the enlarged-diameter surface 230b.

[0051] As described above, the end facing away from the small-diameter section 112 of the outer peripheral wall of the large-diameter section 111 of the plunger 11 is located, regardless of the position of the plunger 11, in the region extending from the bottom dead center to the top dead center between the enlarged-diameter surface 230b and the end of the sliding surface 230a facing the enlarged-diameter surface 230b, and the end of the outer peripheral wall of the large-diameter section 111 of the plunger 11 facing the small-diameter section 112 is located on one side of the end of the sliding surface 230a facing away from the enlarged-diameter surface 230b, the side opposite the enlarged-diameter surface 230b.

[0052] The cover 26 is made of a metal such as stainless steel. The cover 26 comprises a column-shaped section 261 and a base section 262. The column-shaped cover section 261 has a substantially octagonal column shape. The column-shaped cover section 261 has an outer peripheral wall 280, which also has a substantially octagonal column shape. The outer peripheral wall 280 includes flat sections 281, which have a flat shape. The eight flat sections 281 are formed in the circumferential direction of the outer peripheral wall 280 of the cover.

[0053] The cover base section 262 is integrally formed with the column-shaped cover section 261 to close one end of the column-shaped cover section 261. In other words, the cover 26 has a column shape with a base. According to the present embodiment, the cover 26 is formed, for example, by pressing a sheet-shaped material. Accordingly, the thickness of the cover 26 is relatively small. The cover 26 does not form a high-pressure chamber. This allows the thickness of the cover 26 to be smaller.

[0054] The cover 26 has a cover hole section 265, a cover hole section 266, and a cover hole section 267. The cover hole section 265 has a substantially cylindrical shape, which passes through the center point of the cover bottom section 262 in a thickness direction of the cover bottom section. Both the cover hole section 266 and the cover hole section 267 have a substantially cylindrical shape, which connects an inner peripheral wall of the columnar cover section 261 and an outer peripheral wall of the columnar cover section 261, i.e., the flat sections 281 of the outer peripheral wall 280 of the cover.The cover hole section 266 and the cover hole section 267 are essentially designed coaxially such that the cover hole section 266 is arranged facing the cover hole section 267 relative to an axis of the column-shaped cover section 261, which is inserted between the cover hole section 266 and the cover hole section 267.

[0055] The cover 26 encloses the upper housing 21, and the end of the columnar cover section 261, which faces away from the cover base section 262, comes into contact with the surface of the lower housing 22, which faces the upper housing 21. The cover 26 defines a fuel chamber 260 comprising the upper housing 21, the lower housing 22, and the cylinder 23. The end of the columnar cover section 261 and the lower housing 22 are joined together in a circumferential region, for example, by welding. In this way, the space between the columnar cover section 261 and the lower housing 22 is kept liquid-tight. The cover 26 is designed such that the cover hole section 266 corresponds to the intake hole section 212 of the upper housing 21, and that the cover hole section 267 corresponds to the exhaust hole section 214 of the upper housing 21.Operating noise is emitted from the upper section of the cover 26, i.e., from the cover base section 262, which is why the cover base section 262 preferably has high rigidity. According to the present embodiment, the rigidity of the cover base section 262 is increased by providing it with a dome shape. However, the rigidity of the cover base section 262 can also be increased by providing ribs or the like on a flat surface.

[0056] As described above, the cover 26 covers at least part of the cylinder 23, the upper housing 21, and the lower housing 22, and defines the fuel chamber 260 comprising the cylinder 23, the upper housing 21, and the lower housing 22. The fuel chamber 260 has a substantially octagonal column shape between an inner peripheral wall of the columnar cover section 261 and the outer peripheral wall 270 of the housing.

[0057] The cover 26 includes a supply passage section 29. The supply passage section 29 is column-shaped and is designed such that one end of the supply passage section 29 is connected to an outer wall of the cover base section 262 around the cover opening section 265. The supply passage section 29 is designed such that a space within the supply passage section 29 is connected to the fuel chamber 260 via the cover opening section 265. The supply passage section 29 and the cover base section 262 are welded together over their entire surface in the circumferential direction of the supply passage section 29. The supply fuel pipe 7 is connected to the other end of the supply passage section 29. Accordingly, the fuel, which is discharged from the fuel pump 133, flows via the supply fuel pipe 7 and the supply passage section 29 into the fuel chamber 260.

[0058] As in Fig. As shown in Figure 5, the intake valve assembly 300 is located within the intake port section 212 and the intake port section 213 of the upper housing 21, i.e., in the intake passage 216. The intake valve assembly 300 includes a seat element 31, a stopper 35, a valve element 40, a spring 39, and other components.

[0059] The seat element 31 is essentially disc-shaped and is made of a metal such as stainless steel. The seat element 31 is positioned within the intake passage 216, specifically within the intake bore section 212, such that it is essentially coaxial with the intake bore section 212. An outer peripheral wall of the seat element 31 is press-fitted into an inner peripheral wall of the intake bore section 212.

[0060] The seat element 31 includes a communication path 32, a plurality of communication paths 33, and valve seats 310. The communication path 32 has a substantially cylindrical shape and passes through the seat element 31 at a midpoint between one surface and the other surface of the seat element 31. The communication path 32 is substantially coaxial with the seat element 31.

[0061] Each of the communication paths 33 has a substantially cylindrical shape that passes through the seat element 31 between one surface and the other surface of the seat element 31. The communication paths 33 are located radially outside the communication path 32. The majority of communication paths 33 are formed in a circumferential direction of the seat element 31. According to the present embodiment, the majority of communication paths 33 are twelve, and these are arranged at equal intervals to one another in the circumferential direction. Fuel flows uniformly in a state in which the communication paths 33 are formed at equal intervals, as described above. Accordingly, the behavior of the valve element 40, which is described below, is stabilized. The communication paths 33 are arranged on a virtual circle that is centered on an axis of the seat element 31.

[0062] The valve seats 310 are formed in an annular shape around the communication path 32 and the plurality of communication paths 33 on the surface of the seat element 31, which is arranged facing the pressurization chamber 200. In other words, the plurality of valve seats 310 are formed on the surface of the seat element 31, which is arranged facing the pressurization chamber 200.

[0063] The stopper 35 is made of a metal such as stainless steel. The stopper 35 is located between the pressurization chamber 200 and the seat element 31 in the intake passage 216. The stopper 35 includes a small-diameter stopper section 36, a large-diameter stopper section 37, a stopper recess 351, a stopper recess 352, a stopper projection 353, connecting holes 38, and other components.

[0064] The small-diameter stopper section 36 has a substantially cylindrical shape. Its outer diameter is slightly smaller than the inner diameter of the intake port section 213. The large-diameter stopper section 37 also has a substantially cylindrical shape. Its outer diameter is larger than the outer diameter of the small-diameter stopper section 36 and slightly smaller than the inner diameter of the intake port section 212. The large-diameter stopper section 37 is integral with the small-diameter stopper section 36. The large-diameter stopper section 37 is located on one side of the small-diameter stopper section 36 opposite the pressurization chamber 200 and is coaxial with the large-diameter stopper section 36.

[0065] The stopper 35 is positioned in the intake passage 216 such that the small-diameter stopper section 36 is located within the intake hole section 213, and the large-diameter stopper section 37 is located within the intake hole section 212. In other words, the stopper 35 is located in the intake passage 216 and is substantially coaxial with the intake hole section 212 and the intake hole section 213 within the intake hole section 212 and the intake hole section 213.

[0066] An annular stepped surface between the small-diameter stopper section 36 and the large-diameter stopper section 37 is in contact with an annular stepped surface between the intake hole section 212 and the intake hole section 213. In this way, movement of the stopper 35 towards the pressurization chamber 200 is regulated.

[0067] The surface of the large-diameter stopper section 37 of the stopper 35, which faces away from the pressurization chamber 200, is in contact with the surface of the seat element 31, which faces the pressurization chamber 200. In this way, movement of the stopper 35 away from the pressurization chamber 200 is regulated.

[0068] The stopper recess 351 extends from the surface of the large-diameter stopper section 37, which faces the seat element 31, towards the pressurization chamber 200. The stopper recess has a substantially cylindrical shape. The stopper recess 351 is substantially coaxial with the large-diameter stopper section 37. The inner diameter of the stopper recess 351 is smaller than the outer diameter of the large-diameter stopper section 37 and larger than the outer diameter of the small-diameter stopper section 36.

[0069] The stopper recess 352 extends from a bottom surface of the stopper recess 351 towards the pressurization chamber 200. The stopper recess 352 has a substantially cylindrical shape. The stopper recess 352 is substantially coaxial with the stopper recess 351. The inner diameter of the stopper recess 352 is smaller than the inner diameter of the stopper recess 351 and smaller than the outer diameter of the small-diameter stopper section 36.

[0070] The stopper projection 353 extends from the center of the bottom surface of the stopper recess 352 towards the seat element 31. The stopper projection 353 has a substantially cylindrical shape. The stopper projection 353 is substantially coaxial with the stopper recess 352. The end surface of the stopper projection 353, which faces the seat element 31, is located between the seat element 31 and the bottom surface of the stopper recess 351.

[0071] Each of the connecting holes 38 has a substantially cylindrical shape that passes through the small-diameter stopper section 36 between the bottom surface of the stopper recess 352 and the surface of the small-diameter stopper section 36, which faces the pressurization chamber 200. The connecting holes are located radially outside the stopper projection 353. The majority of connecting holes 38 are formed at equal intervals in the circumferential direction of the small-diameter stopper section 36. According to the present embodiment, the four connecting holes 38 are configured as follows: The connecting holes 38 are arranged on a virtual circle centered on an axis of the small-diameter stopper section 36.

[0072] The intake passage 216 is defined by the communication path 32 and the communication paths 33 of the seat element 31, the stopper recess 351 and the stopper recess 352 of the stopper 35, and the connecting holes 38. Accordingly, fuel in the fuel chamber 260 is allowed to enter the pressurization chamber 200 via the intake passage 216, which is defined by the communication path 32, the communication paths 33, the stopper recess 351, the stopper recess 352, the connecting holes 38, and the intake hole 232.

[0073] The valve element 40 is provided within the stopper recess 351, i.e., the valve element 40 is located between the pressurization chamber 200 and the seat element 31. The valve element 40 comprises a valve body 41, tapered sections 42, guide sections 43, and connecting holes 44. The valve body 41, the tapered sections 42, and the guide sections 43 are made of a metal such as stainless steel and are integrally formed together. The valve body 41 is essentially disc-shaped.

[0074] Each of the tapered sections 42 has a substantially annular shape and is integrally formed with the valve body 41 on the radial outer surface of the valve body 41. Each of the tapered sections 42 has a tapered shape such that the surface of the tapered section 42 facing the pressurization chamber 200 tapers towards an axis Ax2 of the valve body 41.

[0075] The guide sections 43 project radially outwards from the valve body 41 to separate the tapered sections 42 in the circumferential direction and are each integrally formed with the valve body 41 and the tapered sections 42. According to the present embodiment, the three guide sections 43 are arranged at equal intervals along the circumferential direction of the valve body 41 to separate the three tapered sections 42 in the circumferential direction. One end of each of the guide sections 43, facing away from the valve body 41, is located on the radial outer surface of an outer edge of the tapered section 42. Each of the guide sections 43 can guide movement of the valve element 40 in the axial direction by allowing it to slide between the end of the guide sections 43 facing away from the valve body 41 and an inner peripheral wall of the stopper recess 351.

[0076] Each of the connecting holes 44 passes through the valve body 41 between one surface and the other surface of the valve body 41. The connecting holes 44 are located at equal intervals in the circumferential direction of the valve body 41. According to the present embodiment, the nine connecting holes 44 are configured as follows: The connecting holes 44 are arranged on a virtual circle centered on the axis Ax2 of the valve body 41.

[0077] The plate thickness of both the valve body 41 and the guide sections 43 of the valve element 40 is less than the distance between the surface of the seat element 31 facing the pressurization chamber 200 and an end surface of the stopper projection 353 facing the seat element 31.

[0078] The surface of the valve element 40 facing the seat element 31 is configured to come into contact with the surface of the seat element facing the pressurization chamber 200, i.e., the valve seats 310. A center point of the surface of the valve element 40 facing the stopper 35 is configured to come into contact with the end surface of the stopper projection 353 facing the seat element 31.

[0079] The valve element 40 is movable in the axial direction in the area of ​​a difference between the plate thickness of the valve body 41 and the guide sections 43 and the distance between the surface of the seat element 31, which faces the pressurization chamber 200, and an end surface of the stopper projection 353, which faces the seat element 31.

[0080] When the surface of the valve element 40 facing the seat element 31 is separated from the surface of the seat element 31 facing the pressurization chamber 200, i.e., when the surface of the valve element 40 facing the seat element 31 is separated from the valve seats 310, the valve element 40 allows fuel to flow in communication path 32 and communication paths 33 by opening communication path 32 and communication paths 33. When the surface of the valve element 40 facing the seat element 31 comes into contact with the valve seats 310, the valve element 40 restricts the fuel flow into the communication paths 33 by closing them. Accordingly, the valve element 40 is a multi-seat valve body that comes into contact with a plurality of valve seats 310.

[0081] When the valve element 40 opens, the fuel can flow through communication path 32, communication paths 33, connecting holes 44, and stopper recess 351. Accordingly, the fuel flowing in fuel chamber 260 can flow through communication path 32, communication paths 33, connecting holes 44, stopper recess 351, stopper recess 352, connecting holes 38, and intake hole 232 towards pressurization chamber 200. It is also possible that the fuel flowing in the pressurization chamber 200 flows through the intake hole 232, the connecting holes 38, the stopper recess 352, the stopper recess 351, the connecting holes 44, the communication paths 33 and the communication path 32 towards the fuel chamber 260. At this time, the fuel flows through the connecting holes 44 of the valve element 40 and around the valve element 40.

[0082] When the valve element 40 closes, the fuel flow between communication path 32 and communication path 33, as well as between connecting holes 44 and the stopper recess 351, is restricted. Accordingly, the fuel flowing in the fuel chamber 260 is restricted from flowing through communication path 32, communication paths 33, connecting holes 44, stopper recess 351, stopper recess 352, connecting holes 38, and intake hole 232 towards the pressurization chamber 200. The fuel is also restricted from flowing from the pressurization chamber 200 through intake hole 232, connecting holes 38, stopper recess 352, stopper recess 351, connecting holes 44, communication paths 33, and communication path 32 towards the fuel chamber 260.

[0083] The spring 39, for example, is a coil spring and is located on the radial outer surface of the stopper projection 353. One end of the spring 39 is in contact with the bottom surface of the stopper recess 352, and the other end is in contact with the surface of the valve element 40, which faces the pressurization chamber 200. The spring 39 biases the valve element 40 towards the seat element 31.

[0084] As in Fig. As shown in Figure 5, the electromagnetic drive unit 500 protrudes radially outwards from the outer peripheral wall 280 of the cover via the cover hole section 266 of the cover 26, starting from the intake hole section 212 of the upper housing 21.

[0085] The electromagnetic drive unit 500 includes a cylindrical element 51, a guide element 52, a needle 53, a spring 54 as a preload element, a movable core 55, a magnetic choke section 56, a fixed core 57, a coil 60, a yoke 641, a yoke 645, a connector 65 and other parts.

[0086] The cylindrical element 51 comprises a first cylindrical section 511, a second columnar section 512, and a third cylindrical section 513. The first cylindrical section 511, the second columnar section 512, and the third cylindrical section 513 are all made of a magnetic material, for example. The first cylindrical section 511 has a substantially cylindrical shape.

[0087] The second column-shaped section 512 has a columnar form. The second column-shaped section 512 is formed substantially coaxially and integrally with the first cylindrical section 511 such that one end of the second column-shaped section 512 is connected to an end of the first cylindrical section 511. The maximum outer diameter of the second column-shaped section 512 is smaller than the outer diameter of the end of the first cylindrical section 511 that faces the second column-shaped section 512.

[0088] The third cylindrical section 513 has a substantially cylindrical shape. The third cylindrical section 513 is formed substantially coaxially and integrally with the second columnar section 512 such that one end of the third cylindrical section 513 is connected to the end of the second columnar section 512 that faces away from the first cylindrical section 511. The outer diameter of the third cylindrical section 513 is smaller than the maximum outer diameter of the second columnar section 512.

[0089] Screw threads are formed in an outer peripheral wall of the end of the first cylindrical section 511, which is located away from the second columnar section 512. Threaded grooves corresponding to the screw threads of the first cylindrical section 511 are formed in an inner peripheral wall of the end of the intake port section 212 of the upper housing 21, which is located away from the intake port section 213.

[0090] The cylindrical element 51 is designed such that the threads of the first cylindrical section 511 are screwed into the threaded grooves of the upper housing 21. The end surface of the first cylindrical section 511 of the cylindrical element 51, which faces the pressurization chamber 200, biases the seat element 31 and the stopper 35 towards the pressurization chamber 200. Accordingly, the seat element 31 and the stopper 35 are in contact with each other to regulate movement of the seat element 31 and the stopper 35 in the axial direction. The stepped surface between the small-diameter stopper section 36 and the large-diameter stopper section 37 is pressed against the stepped surface between the intake port section 213 and the intake port section 212.Accordingly, starting from the step surface between the stopper section 36 with small diameter and the stopper section 37 with large diameter, an axial force acts on the step surface between the intake hole section 213 and the intake hole section 212 towards the pressure chamber 200.

[0091] The outer peripheral wall of the second columnar section 512 has a columnar shape with flat surfaces, such as a hexagonal column. Accordingly, a tool corresponding to the outer peripheral wall of the second columnar section 512 can be used to screw the cylindrical element 51 into the intake port section 212 of the upper housing 21, in order to screw the cylindrical element 51 into the intake port section 212 in a relatively simple manner.

[0092] The first cylindrical section 511 of the cylindrical element 51 is located within the cover hole section 266 of the cover 26. Accordingly, the end of the first cylindrical section 511 facing the pressurization chamber 200 is located within the columnar cover section 261. The end of the first cylindrical section 511 facing away from the pressurization chamber 200, the second columnar section 512, and the third cylindrical section 513 are located outside the columnar cover section 261. The cylindrical element 51 is configured such that one axis of the cylindrical element 51 is orthogonal to an axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder 23.

[0093] The inner diameter of a section of the cylindrical element 51 facing the pressurization chamber 200 is larger than the inner diameter of a section of the cylindrical element 51 facing away from the pressurization chamber 200. A stepped surface 514, having a substantially annular shape and facing the pressurization chamber 200, is formed within the cylindrical element 51. The stepped surface 514 is positioned, with respect to a connecting section between the first cylindrical section 511 and the second columnar section 512, slightly towards the pressurization chamber 200 in the axial direction of the cylindrical element 51 to ensure sufficient wall thickness.

[0094] The first cylindrical section 511 includes perforated sections 515 that pass through the first cylindrical section 511 between its inner and outer peripheral walls. The perforated sections 515 are formed at equal intervals around the circumference of the first cylindrical section 511. According to the present embodiment, six perforated sections 515 are arranged. The perforated sections 515 are located approximately between the outer peripheral wall 270 of the housing and the outer peripheral wall 280 of the cover in the axial direction of the first cylindrical section 511. This allows the fuel in the fuel chamber 260 to flow through the perforated sections 515 into the first cylindrical section 511 and through the intake port 216 towards the pressurization chamber 200.

[0095] A tubular filter 510 is positioned at a location corresponding to the perforated sections 515 within the first cylindrical section 511. The filter 510 is capable of collecting foreign substances contained in the fuel flowing from the fuel chamber 260 to the pressurization chamber 200. One end of the filter 510, facing the outer peripheral section of the pressurization chamber 200, is press-fitted into the inner peripheral wall of the first cylindrical section 511, and the other end of the filter 510, facing away from the pressurization chamber 200, is in contact with the guide element 52. Accordingly, the fuel flowing in the fuel chamber 260 only enters the intake port 216 after passing through the filter 510.The filter 510 is assembled by gently squeezing it to achieve secure contact with the guide element 52.

[0096] A weld ring 519 is provided outside the cover 26 on the radial outer surface of the first cylindrical section 511 of the cylindrical element 51. The weld ring 519 has a substantially cylindrical shape and is, for example, made of metal. The weld ring 519 is designed such that one end of the weld ring 519, which faces the pressurization chamber 200, extends radially outward and comes into contact with a periphery of the cover hole section 266 of the flat section 281 of the outer peripheral wall 280 of the cover. The end of the weld ring 519 facing the pressurization chamber 200 is welded to the flat section 281 of the outer peripheral wall 280 of the cover along its entire circumference.A section of the weld ring 519, which faces away from the pressurization chamber 200, is welded circumferentially to the outer peripheral wall of the first cylindrical section 511. This configuration reduces fuel leakage from the fuel chamber 260 through a gap between the cover hole section 266 and the outer peripheral wall of the first cylindrical section 511 to the outside of the cover 26. A load during high-pressure operation is absorbed by a screw of the cylindrical component 51, thus no load acts on the weld ring 519.

[0097] The guide element 52 is provided within the first cylindrical section 511. The guide element 52 has a substantially cylindrical shape and is, for example, made of metal. The guide element 52 is fixed to the inside of the first cylindrical section 511 such that an outer peripheral wall of the guide element 52 is fitted against an inner peripheral wall of the first cylindrical section 511, and that an outer edge of one end surface of the guide element 52 comes into contact with the stepped surface 514 of the cylindrical element 51. A section 516 with a reduced diameter is formed in a section corresponding to the guide element 52 in the inner peripheral wall of the first cylindrical section 511. The reduced-diameter section 516 projects radially inward from the inner peripheral wall of the first cylindrical section 511.Accordingly, the inner peripheral wall of the first cylindrical section 516 has a smaller inner diameter at the section 511 with reduced diameter. Therefore, it is possible that the guide element 52 is press-fitted into the section 516 with reduced diameter.

[0098] The guide element 52 has an axial hole 521 and a connecting hole 522. The axial hole 521 passes through a center point of the guide element 52 in the axial direction. The axial hole 521 is essentially coaxial with the guide element 52.

[0099] The connecting hole 522 passes through the guide element 52 between a surface of the guide element 52 facing the pressurization chamber 200 and the surface of the guide element 52 facing away from the pressurization chamber 200. The connecting hole 522 is located radially outside the axial hole 521. The connecting hole 522 communicates with an interior space of the first cylindrical section 511 extending from the guide element 52 towards the pressurization chamber 200 and with an interior space of the first cylindrical section 511 adjacent to an end of the guide element 52 facing away from the pressurization chamber 200.The guide element 52 includes a cylindrical section 523 which projects from the periphery of the axial hole 521 on the end surface of the guide element 52, which is arranged facing the pressurization chamber 200, towards the pressurization chamber 200.

[0100] The needle 53 is provided within the cylindrical element 51. The needle 53 is made of metal, for example. The needle 53 comprises a needle body 531 and a stop section 532. The needle body 531 has a substantially cylindrical shape. The stop section 532 is integrally formed with the needle body 531 and extends from the outer peripheral wall of the needle body 531 to the radial outer surface. The stop section 532 has a substantially annular shape.

[0101] The needle 53 is configured such that the needle body 531 is inserted through the axial hole 521 of the guide element 52, and that the stop section 532 is located between the pressurization chamber 200 and the guide element 52. One end of the needle body 531, which faces the pressurization chamber 200, is located within the communication path 32 of the seat element 31 and is configured to contact the surface of the valve element 40, which faces away from the pressurization chamber 200. The end of the needle body 531 facing away from the pressurization chamber 200 is located on one side of the end surface of the third cylindrical section 513, which faces away from the second columnar section 512 and opposite the pressurization chamber 200.

[0102] The outer diameter of a section of the needle body 531 corresponding to the axial hole 521 is slightly smaller than the inner diameter of the axial hole 521. The outer diameter of the stop section 532 is larger than the outer diameter of the axial hole 521. The needle 53 is able to move back and forth axially within the cylindrical element 51. An outer peripheral wall of the needle body 531 is able to slide on the axial hole 521. Accordingly, the guide element 52 is able to guide the needle 53 such that it moves axially. A bypass section is formed at an outer peripheral end of the guide element 52 to prevent deformation of one end of the axial hole 521 of the guide element 52. The bypass section is not press-fitted.

[0103] The spring 54 can be a coil spring and is arranged radially outside the needle body 531. One end of the spring 54 is in contact with the surface of the guide element 52, which faces the pressurization chamber 200, and the other end of the spring 54 is in contact with the surface of the stop section 532, which faces away from the pressurization chamber 200. In other words, the stop section 532 stops the other end of the spring 54. The spring 54 biases the needle 53 towards the pressurization chamber 200. The preload force of spring 54 is set higher than the preload force of spring 39. Accordingly, spring 54 preloads the valve element 40 via the needle 53 towards the pressurization chamber 200 in order to press the surface of the valve element 40, which is arranged facing the pressurization chamber 200, against the stopper projection 353.In this state, the valve element 40 is separated from the valve seats 310 of the seat element 31 in order to open.

[0104] The movable core 55 has a substantially cylindrical shape and is made, for example, of a magnetic material. The movable core 55 includes an axial hole 553 and a connecting hole 554. The axial hole 553 passes through a center point of the movable core 55 in the axial direction. The axial hole 553 is substantially coaxial with the movable core 55. The inner diameter of the axial hole 553 is smaller than the outer diameter of the end of the needle body 531, which is located away from the pressurization chamber 200.

[0105] The movable core 55 is integrally formed with the needle 53 such that an inner peripheral wall of the axial hole 553 at the end of the needle body 531 facing away from the pressurization chamber 200 is fitted into an outer peripheral wall of the needle body 531. The movable core 55 is press-fitted into the needle 53 and restricted in its movement relative to the needle 53. The end surface 551 of the movable core 55 facing away from the pressurization chamber 200 is essentially in the same plane as the end surface of the needle body 531 facing away from the pressurization chamber 200.

[0106] The connecting hole 554 passes through the movable core 55 between the end surface 551, which faces away from the pressurization chamber 200, and the end surface 552, which faces the pressurization chamber 200. The connecting hole 554 is located radially outside the axial hole 553. The connecting hole 554 reduces fluid resistance generated during the reciprocating motion of the movable core 55, thereby enabling the movable core 55 to move with good responsiveness. The connecting hole 554 allows the fuel to flow in a space between the movable core 55 and the fixed core 57. Accordingly, dynamic pressure changes are limited, thus reducing cavitation erosion.The movable core 55 includes a cylindrical section that extends from the periphery of the axial hole 553 at the end surface 552 of the movable core 55, which is arranged facing the pressurization chamber 200, towards the pressurization chamber 200.

[0107] According to the present embodiment, the center of gravity of both the needle 53 and the movable core 55, which are integrally provided, is always located on the axis of the needle 53 and within the guide element 52 from the opening to the closing of the valve. Accordingly, the movements of the needle 53 and the movable core 55 can be stabilized in the axial direction.

[0108] The magnetic choke section 56 has a substantially cylindrical shape and is, for example, made of a non-magnetic element. The inner and outer diameters of the magnetic choke section 56 are substantially the same as the inner and outer diameters of the third cylindrical section 513. The magnetic choke section 56 is located on one side of the cylindrical element 51, facing the pressurization chamber 200. The magnetic choke section 56 is substantially coaxial with the third cylindrical section 513. The magnetic choke section 56 and the third cylindrical section 513 are joined together, for example, by welding. The end surface 551 of the movable core 55, which faces away from the pressurization chamber 200, is located within the magnetic choke section 56.

[0109] The solid core 57, for example, is made of a magnetic material. The solid core 57 comprises a small-diameter section 573 and a large-diameter section 574. The small-diameter section 573 has a substantially cylindrical shape. The outer diameter of the small-diameter section 573 is slightly larger than the inner diameter of the magnetic choke section 56. The small-diameter section 573 is press-fitted into the magnetic choke section 56.

[0110] The large-diameter solid core section 574 has a substantially cylindrical shape and is integrally formed with the small-diameter solid core section 573. One end of the large-diameter solid core section 574 is axially connected to an end of the small-diameter solid core section 573 such that the large-diameter solid core section 574 is coaxial with the small-diameter solid core section 573. An outer diameter of the large-diameter solid core section 574 is larger than an outer diameter of the small-diameter solid core section 573 and is substantially equal to an outer diameter of the magnetic choke section 56.

[0111] The solid core 57 is positioned on one side of the cylindrical element 51 opposite the pressurization chamber 200 such that the small-diameter section 573 of the solid core is located within the end of the magnetic choke section 56 that faces away from the cylindrical element 51. The solid core 57 and the magnetic choke section 56 are joined together, for example, by welding. An annular stepped surface between the small-diameter section 573 of the solid core and the large-diameter section 574 of the solid core is in contact with the end surface of the magnetic choke section 56 that faces away from the cylindrical element 51.An end surface 571 of the solid core 57, which faces the pressurization chamber 200, is located between the pressurization chamber 200 and the end surface of the magnetic throttle section 56, which faces away from the cylindrical element 51. The solid core 57 is substantially coaxial with the magnetic throttle section 56. In a state in which the valve element 40 is separated from the valve seats 310, with the needle 53 biased towards the pressurization chamber 200 by the spring 54, a gap is created between the end surface 571 of the solid core 57, which faces the pressurization chamber 200, and the end surface 551 of the movable core 55, which faces away from the pressurization chamber 200.

[0112] According to the present embodiment, the cylindrical element 51, the guide element 52, the spring 54, the needle 53, the movable core 55, the magnetic choke section 56, the fixed core 57 and the filter 510 are pre-assembled into a body to provide a sub-assembly forming a first electromagnetic drive unit 501.

[0113] More precisely, the spring 54 and the needle 53 are initially assembled on the guide element 52, and the movable core 55 is press-fitted into the needle 53. Subsequently, the magnetic choke section 56 is press-fitted and welded to the small-diameter section 573 of the fixed core 57, thus joining the magnetic choke section 56 and the cylindrical element 51. Afterward, the guide element 52, in the state described above, is press-fitted into the cylindrical element 51, also in the state described above. At this time, the filter 510 is press-fitted into the inner surface of the first cylindrical section 511 until the end of the filter 510 comes into contact with the surface of the guide element 52 facing the pressurization chamber 200. The assembly of the first electromagnetic drive unit 501 as a subassembly is completed by the preceding steps.

[0114] The coil 60 comprises a spool 61 and a winding section 62. The spool 61 has a substantially cylindrical shape and is made, for example, of resin. The spool 61 is substantially coaxial with the cylindrical element 51 and is located radially outside the end of the cylindrical element 51 facing away from the pressurization chamber 200 and the ends of the movable core 55, the magnetic choke section 56, and the fixed core 57 facing the pressurization chamber 200. The spool 61 has a portion in the axial direction that is located on the radial outside of the movable core 55.

[0115] The winding section 62 is formed by a wire 620. The wire 620 has a linear shape and is made of an electrically conductive material such as copper. The winding section 62 has a substantially cylindrical shape, which is formed by winding the wire 620 around an outer peripheral wall of the coil former 61. The coil 61 includes an outer cylindrical surface 600, which is a virtual surface in contact with an outer peripheral surface of the winding section 62, and an inner cylindrical surface 601 and an inner cylindrical surface 602, which are virtual surfaces in contact with an inner peripheral surface of the winding section 62. The diameter of the inner cylindrical surface 601 differs from that of the inner cylindrical surface 602. The coil former 61 corresponds to a "winding formation section".

[0116] The outer cylindrical surface 600 has a substantially cylindrical shape. The inner cylindrical surface 601 has a substantially cylindrical shape and is positioned within a section of the outer cylindrical surface 600 that faces the pressurization chamber 200. The inner cylindrical surface 602 has a substantially cylindrical shape and is positioned between the pressurization chamber 200 and the inner cylindrical surface 601 within a section of the outer cylindrical surface 600 that faces the pressurization chamber 200. One diameter of the inner cylindrical surface 602 is larger than one diameter of the inner cylindrical surface 601. The inner cylindrical surfaces 601 and 602 are located on the outer peripheral wall of the coil former 61.In other words, the section of the coil body 61 which is arranged facing the pressure chamber 200 in the axial direction has an outer diameter that differs from the outer diameter of the section of the coil body 61 which is arranged away from the pressure chamber 200.

[0117] The coil 60 includes a connecting surface 605, which is a virtual surface between the inner cylindrical surface 601 and the inner cylindrical surface 602. The connecting surface 605 is located on the outer peripheral wall of the coil former 61, and at least a portion of the connecting surface 605 is perpendicular to the axis of the coil former 61. In this way, the wire 620 is wound around the outer peripheral wall of the coil former 61 to form the winding section 62 with a cylindrical shape. In other words, the wire 620 is wound radially outward around the inner cylindrical surface 601, the inner cylindrical surface 602, and the connecting surface 605.

[0118] Both yoke 641 and yoke 645 are made of a magnetic material. Yoke 641 has a cylindrical shape with a base. A yoke hole section 642 has a substantially circular shape and is formed at a center point of the base of yoke 641. A small gap exists between yoke 641 and the outer peripheral wall of the first cylindrical section 511. This gap is configured to allow the inner peripheral wall of yoke hole section 642 in the base section of yoke 641 to contact the outer peripheral wall of the first cylindrical section 511, or to ensure that the gap does not diminish the attractive force. A cylindrical section of yoke 641 is located on the radial outer surface of coil 60. The space between yoke 641 and coil 60 is filled with resin.

[0119] The yoke 645 has a plate shape and closes one end of the cylindrical section of the yoke 641, which is located away from the bottom section. An outer edge of the end surface of the yoke 645, which faces the pressurization chamber 200, is in contact with the cylindrical section of the yoke 641. A center point of the end surface of the yoke 645, which faces the pressurization chamber 200, is in contact with an end surface 572 of the solid core 57, which faces away from the pressurization chamber 200, and is welded to the end surface 572 of the solid core 57.

[0120] Starting from a notch formed in part of the cylindrical section of the yoke 641, the connector 65 projects radially outwards in the circumferential direction (compare Fig. 2) Connector 65 has a terminal 651. Terminal 651 is electrically connected to wire 620 of coil 60. A cable harness 6 is connected to connector 65. This configuration allows power to be supplied to winding section 62 of coil 60 via the cable harness 6 and terminal 651.

[0121] According to the present embodiment, the coil 60, the yoke 641 and the connector 65 are pre-assembled into a sub-assembly that forms a second electromagnetic drive unit 502.

[0122] More precisely, the terminal 651 is initially press-fitted into the coil former 61. Subsequently, the wire 620 is wound around the coil former 61, and the terminal 651 and the wire 620 are welded together. In other words, the terminal 651 and the wire 620 are joined. With the coil former 61 and other components assembled as described above inserted into the yoke 641, resin is poured in to form the connector 65. The outer edge of the yoke 645 is then welded to the cylindrical section of the yoke 641. The assembly of the second electromagnetic drive unit 502 as a subassembly is completed by the preceding steps.

[0123] A gap is formed between the end surface of the resin section within the yoke 641, which faces away from the pressurization chamber 200, and the end surface of the yoke 645, which faces the pressurization chamber 200. This improves the assembly of the yoke 641 and the yoke 645. Furthermore, the gap is small enough to prevent water from flowing through it. This configuration therefore reduces the ingress of water into the yoke 641, thereby reducing corrosion of components such as the solid core 57 and the cylindrical element 51.

[0124] The coil 60 generates an electromagnetic force when it is energized in accordance with a command originating from the ECU via the wiring harness 6 and the terminal 651. As a result, a magnetic circuit is formed in the surfaces of the yoke 641, the yoke 645, the fixed core 57, the movable core 55, and the cylindrical component 51, excluding the magnetic throttle section 56. In this case, an attractive force is generated between the fixed core 57 and the movable core 55, causing the movable core 55, together with the needle 53, to be attracted towards the fixed core 57. Consequently, the valve element 40 moves towards the valve seats 310 of the seat element 31 due to a preload force from the spring 39. As a result, the valve element 40 comes into contact with the valve seats 310 and is closed. As described above, the electromagnetic drive unit 500 generates an electromagnetic force when the coil 60 is energized.In this case, an attractive force is generated between the fixed core 57 and the movable core 55. Accordingly, the movable core 55 and the needle 53 move in the closing direction of the valve element 40 in order to close the valve element 40.

[0125] In this way, the coil 60 is able to generate an attractive force between the fixed core 57 and the movable core 55 by exciting the winding section 62, and to move the movable core 55 and the needle 53 in the closing direction. When the movable core 55 and the needle 53 move in the closing direction, the cylindrical section 523 of the guide element 52 comes into contact with the stop section 532 of the needle 53. Accordingly, the movement of the movable core 55 and the needle 53 in the closing direction is regulated. Since the movement of the movable core 55 and the needle 53 in the closing direction is regulated by the contact between the cylindrical section 523 and the stop section 532, the movable core 55 and the fixed core 57 are arranged separately from each other.In other words, according to the present embodiment, the movable core 55 and the fixed core 57 do not come into contact with each other, even when the movable core 55 and the needle 53 are attracted towards the fixed core 57.

[0126] The connecting hole 522 has an opening to effect a damping action on a portion of the guide element 52 that faces away from the pressurizing chamber 200. A negative pressure generated in the opposite direction to the damping action can reduce the collision velocity at the time of a collision between the cylindrical section 523 and the stop section 532, thereby reducing NV.

[0127] When coil 60 is not energized, valve element 40 is open. In this case, fuel chamber 260 is connected to pressurization chamber 200. When plunger 11 moves away from pressurization chamber 200 in this state, the volume of pressurization chamber 200 increases. Accordingly, fuel in fuel chamber 260 flows through orifice section 515 into the first cylindrical section 511. The fuel is then drawn into pressurization chamber 200 through intake orifice 232. When plunger 11 moves towards pressurization chamber 200 in an open position, the volume of pressurization chamber 200 decreases. In this case, fuel in pressurization chamber 200 flows through intake orifice 232 towards valve element 40.

[0128] When the coil 60 is energized during a movement of the plunger 11 towards the pressurization chamber 200, the valve element 40 is closed, thus preventing the fuel from flowing between the fuel chamber 260 and the pressurization chamber 200. If the plunger 11 continues to move towards the pressurization chamber 200 while the valve element 40 is closed, the volume of the pressurization chamber 200 continues to decrease. In this state, the fuel in the pressurization chamber 200 is pressurized.

[0129] In this way, the amount of fuel pressurized in the pressurization chamber 200 is controlled by closing the valve element 40 at any point during the movement of the plunger 11 towards the pressurization chamber 200, using the electromagnetic drive unit 500. According to the present embodiment, the intake valve unit 300 and the electromagnetic drive unit 500 form a normally open valve device.

[0130] According to the present embodiment, the connecting holes 44 in the valve element 40 are formed on the radial inner side of the center point of each of the connecting holes 38 of the stopper 35. This configuration diverts the fuel, which is recirculated from the pressurization chamber 200, into sections inside and outside the valve element 40 to prevent self-closing. An edge of the valve element 40 facing the seat element 31 is chamfered. This configuration allows the fuel to flow freely and improves the self-closing boundary.

[0131] According to the present embodiment, the coil 60 is not energized when the fuel injectors 138 are not injecting fuel. In other words, the coil 60 is not energized when the fuel or fuel flow is interrupted. In this state, there is no fuel discharged from the high-pressure pump 10. A load on the spring 54 is applied in this state to prevent the valve element 40 from closing on its own.

[0132] When the coil 60 is not energized, i.e., the coil is in a non-energized state, the end surface 551 of the movable core 55, which is located away from the pressurization chamber 200, i.e., the end surface 551 of the movable core, which is located towards the fixed core 57, is located between a center point Ci1 of the inner cylindrical surface 601 in the axial direction, which is an inner cylindrical surface with the smallest diameter, and a center point Co1 of the outer cylindrical surface 600 in the axial direction, as shown in Fig. Figure 5 is shown. Additionally, an end surface 552 of the movable core 55, which is arranged facing the pressurization chamber 200, is located between the fixed core 57 and the end surface 621 of the winding section 62, which is arranged facing the pressurization chamber 200.

[0133] According to the present embodiment, the end surface 551 of the movable core 55, which faces the fixed core 57, is located between the center point Ci1 and the center point Co1, even when the movable core 55 is in a position closest to the fixed core 57 during excitation of the coil 60. In other words, the end surface 551 of the movable core 55, which faces the fixed core 57, is always located between the center point Ci1 and the center point Co1, regardless of the excitation state of the coil 60.

[0134] As in Fig. As shown in Figure 6, the discharge passage section 700 protrudes beyond the cover hole section 267 of the cover 26 from the discharge hole section 214 of the upper housing 21 towards the radial outside of the outer peripheral wall 280 of the cover.

[0135] The discharge passage section 700 includes a discharge port 70, a discharge seat element 71, an intermediate element 81, an overflow seat element 85, a discharge valve 75, a spring 79 as a discharge valve preload element, an overflow valve 91, a spring 99 as an overflow valve preload element, and a stop element 95.

[0136] The discharge port 70 has a substantially cylindrical shape and is made, for example, of metal such as stainless steel. Screw threads are formed on an outer peripheral wall of a section of the discharge port 70 at a predetermined distance from one end to the other. Threaded grooves corresponding to the threads of the discharge port 70 are formed in an inner peripheral wall of the end of the discharge hole section 214 of the upper housing 21, which is located facing away from the discharge hole section 215. The discharge port 70 is designed such that the screw threads are screwed into the screw grooves of the upper housing 21.

[0137] The discharge port 70 is provided within the cover hole section 267 of the cover 26. The end of the discharge port 70 facing the pressurization chamber 200 is located in the discharge hole section 214 within the columnar cover section 261, i.e., in the discharge passage 217, and the end of the discharge port 70 facing away from the pressurization chamber 200 is located outside the columnar cover section 261. The discharge port 70 is configured such that one axis of the discharge port 70 is orthogonal to the axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder 23. According to the present embodiment, the discharge port 70 is substantially coaxial with the cylindrical element 51.

[0138] The inner diameter of a section of the discharge port 70 facing the pressurization chamber 200 is larger than the inner diameter of a section of the discharge port 70 facing away from the pressurization chamber 200. Accordingly, a stepped surface 701, having a substantially annular shape and facing the pressurization chamber 200, is formed within the discharge port 70. This stepped surface 701 is located between the pressurization chamber 200 and the outer peripheral wall 280 of the cover.

[0139] The discharge port 70 has a discharge passage 705. The fuel discharged from the pressurization chamber 200 flows through the discharge passage section 705. The discharge port 70 corresponds to a "discharge passage formation section".

[0140] The discharge port 70 includes a lateral perforation 702 that passes through the discharge port 70 between an inner peripheral wall and an outer peripheral wall of the discharge port 70. The discharge port 70 can include a plurality of lateral perforations 702 formed at equal intervals in the circumferential direction of the discharge port 70. In this embodiment, the discharge port 70 includes one lateral perforation 702. The lateral perforation 702 is located between the outer peripheral wall 270 of the housing and the outer peripheral wall 280 of the cover in the axial direction of the discharge port 70. This allows the fuel to flow through the discharge passage 705, via the overflow valve 91 described below and the lateral perforation 702, towards the fuel chamber 260.

[0141] The discharge seat element 71 comprises a discharge element body 72, a discharge hole 73, and a discharge valve seat 74. The discharge element body 72 is essentially disc-shaped and is made, for example, of metal. The outer diameter of the discharge element body 72 is slightly larger than the inner diameter of the end of the discharge port 70 facing the pressurization chamber 200. The discharge element body 72 is positioned in the discharge passage 705 such that an outer peripheral wall of the discharge element body 72 is press-fitted into the inner peripheral wall at the end of the discharge port 70 facing the pressurization chamber 200.

[0142] The discharge element body 72 includes a discharge recess 721, an inner projection 722, and an outer projection 723. The discharge recess 721 extends from the center point of the end surface of the discharge element body 72, which faces away from the pressurization chamber 200, towards the pressurization chamber 200. The discharge recess 721 has a substantially cylindrical shape. The inner projection 722 projects from the end surface of the discharge element body 72, which faces the pressurization chamber 200, towards the pressurization chamber 200. The inner projection 722 has a substantially annular shape. The outer projection 723 extends from the end surface of the discharge element body 72, which is arranged facing the pressurization chamber 200, towards the pressurization chamber 200.The outer projection 723 has an essentially ring-shaped form and is located radially outside the inner projection 722.

[0143] The discharge hole 73 passes through the discharge seat element 71 between the end surface of the discharge element body 72, which faces the pressurization chamber 200, and a bottom surface of the discharge recess 721. The discharge hole 73 has a substantially cylindrical shape and is located radially inside the inner projection 722. The discharge valve seat 74 has a substantially annular shape and is located around the discharge hole 73 on the bottom surface of the discharge recess 721.

[0144] The discharge recess 721, the inner projection 722, the outer projection 723, the discharge hole 73 and the discharge valve seat 74 are essentially coaxial with the discharge element body 72. The inner projection 722 and the outer projection 723 are in contact with the periphery of the discharge hole section 215 on the bottom surface of the discharge hole section 214 of the upper housing 21.

[0145] The intermediate element 81 comprises an intermediate element body 82 and first passages 83. The intermediate element body 82 is essentially disc-shaped and is, for example, made of metal. The intermediate element body 82 in the discharge passage 705 is arranged on one side of the discharge seat element 71 opposite the pressurization chamber 200. An outer diameter of the intermediate element body 82 is slightly smaller than an inner diameter of the end of the discharge connection 70 that faces the pressurization chamber 200. The intermediate element body 82 is essentially coaxial with the discharge element body 72 such that the end surface of the intermediate element body 82 facing the pressurization chamber 200 comes into contact with the end surface of the discharge element body 72 facing away from the pressurization chamber 200.

[0146] An intermediate recess 821 is formed in the intermediate element body 82. The intermediate recess 821 extends away from the pressure chamber 200, starting from a center point on the end surface of the intermediate element body 82, which faces the pressure chamber 200. The intermediate recess 821 is essentially coaxial with the intermediate element body 82.

[0147] The first passages 83 extend through the intermediate element body 82 between the end surface of the intermediate element body 82 facing the side of the pressurization chamber 200 and the end surface of the intermediate element body 82 facing away from the pressurization chamber 200. Each of the first passages 83 has a substantially cylindrical shape and is located radially outside the intermediate recess 821. The first passages 83 are formed at equal intervals in the circumferential direction of the intermediate element body 82. According to the present embodiment, the majority of first passages 83 are the five first passages 83. The first passages 83 are each connected to the pressurization chamber 200 via the discharge recess 721, the discharge hole 73, the discharge hole section 215, and the discharge hole 233.

[0148] The overflow element 85 comprises an overflow element body 86, an overflow hole 87, an overflow valve seat 88, secondary passages 89, an outer peripheral overflow recess 851, a lateral overflow hole 852, and a lateral hole 853. The overflow element body 86 is, for example, made of metal. The overflow element body 86 has a cylindrical section 861 of the overflow element and an overflow element bottom section 862.

[0149] The cylindrical section 861 of the overflow element has a substantially cylindrical shape. The overflow element bottom section 862 is integrally formed with the cylindrical section 861 of the overflow element such that the overflow element bottom section 862 closes one end of the cylindrical section 861 of the overflow element. In other words, the overflow element body 86 has a cylindrical shape with a bottom.

[0150] The overflow element body 86 in the discharge passage 705 is located on one side of the intermediate element 81 opposite the pressurization chamber 200. The outer diameter of the cylindrical section 861 of the overflow element is slightly smaller than the inner diameter of a section of the discharge port 70 located between the pressurization chamber 200 and the step surface 701. Accordingly, the overflow element body 86 is designed with an intermediate fit within the discharge port 70.The overflow element body 86 is substantially coaxial to the intermediate element body 82 such that the end surface of the cylindrical section 861 of the overflow element, which is arranged facing the pressurization chamber 200, contacts an outer edge of the end surface of the intermediate element body 82, which is arranged away from the pressurization chamber 200, and that an outer edge of the end surface of the cylindrical section 861 of the overflow element, which is arranged away from the pressurization chamber 200, contacts the step surface 701 of the discharge port 70.

[0151] The overflow hole 87 passes through the overflow element bottom section 862 between the center point of a surface of the overflow element bottom section 862 facing the pressurization chamber 200 and the surface of the overflow element bottom section 862 facing away from the pressurization chamber 200. The overflow hole 87 has a substantially cylindrical shape. The overflow valve seat 88 is located around the overflow hole 87 on the surface of the overflow seat element bottom section 862 facing the pressurization chamber 200. The overflow valve seat 88 has an annular shape. The overflow valve seat 88 tapers in a direction away from the pressurization chamber 200 towards an axis of the cylindrical section 861 of the overflow element. The overflow hole 87 and the overflow valve seat 88 are essentially coaxial to the overflow element body 86.

[0152] The second passages 89 extend through the cylindrical section 861 of the overflow element between the end surface of the cylindrical section 861 of the overflow element facing the pressurization chamber 200 and the end surface of the cylindrical section 861 of the overflow element opposite the pressurization chamber 200. Each of the second passages has a substantially cylindrical shape. The second passages 89 are formed at equal intervals in the circumferential direction of the cylindrical section 861 of the overflow element. According to the present embodiment, the majority of second passages 89 are four. According to the present embodiment, the length of the intermediate element body 82 in the axial direction is smaller or shorter than the length of the cylindrical section 861 of the overflow element in the axial direction.Accordingly, the length of each of the first passages 83 is smaller than the length of each of the second passages 89.

[0153] The outer peripheral overflow recess 851 extends radially inwards from the outer peripheral wall of the cylindrical section 861 of the overflow element and has a substantially cylindrical shape. The outer peripheral overflow recess 851 communicates with the fuel chamber 260 via the lateral hole section 702 of the discharge port 70. The lateral overflow hole 852 passes through the cylindrical section 861 of the overflow element between the outer peripheral overflow recess 851 and an inner peripheral wall of the cylindrical section 861 of the overflow element.

[0154] The lateral hole 853 passes through the cylindrical section 861 of the overflow element between the outer peripheral overflow recess 851 and the inner peripheral wall of the cylindrical section 861 of the overflow element. The lateral hole 853 has a substantially cylindrical shape and is located between the pressurization chamber 200 and the lateral overflow hole 852. In this case, a space in the discharge passage 705, which is located adjacent to the end of the overflow element bottom section 862 facing away from the pressurization chamber 200, communicates with the fuel chamber 260 through the overflow hole 87, the lateral overflow hole 852, the outer peripheral overflow recess 851, and the lateral hole section 702.

[0155] According to the present embodiment, an annular recess 800 is formed in the intermediate element 81. The annular recess 800 extends from the end surface of the intermediate element body 82, which faces away from the pressurization chamber 200, towards the pressurization chamber 200. In other words, the annular recess extends from the surface of the intermediate element body 82, which faces the overflow seat element 85, towards the pressurization chamber 200. The annular recess has a substantially ring-shaped form. The annular recess 800 is essentially coaxial to the intermediate element body 82. The annular recess 800 fluidly connects the ends of all the first passages 83, which are arranged away from the pressurization chamber 200, and the ends of all the second passages 89, which are arranged towards the pressurization chamber 200.In other words, the first passages 83 and the second passages 89 are connected to each other through the annular recess 800. The first passages 83 and the second passages 89 are connected to each other through the annular recess 800 regardless of how the intermediate element 81 and the overflow seat element 85 rotate relative to the axis.

[0156] Accordingly, the pressurization chamber 200 is connected to the space in the discharge passage 705 on one side of the cylindrical section 861 of the overflow element opposite the pressurization chamber 200 via the discharge hole 233, the discharge hole section 215, the discharge hole 73, the discharge recess 721, the first passages 83, the annular recess 800 and the second passages 89.

[0157] When the fuel flows through the annular recess 800 between the first passages 83 and the second passages 89, the fuel flows radially through the annular recess 800. The depth of the annular recess 800 is set such that it is equal to or longer than the diameter of each of the first passages 83 to ensure a flow path area.

[0158] As described above, the discharge port 70 is designed such that the screw threads formed on the outer peripheral wall are screwed into the screw grooves of the upper housing 21. A gap is formed between the end of the discharge port 70 facing the pressurization chamber 200 and the bottom surface of the discharge hole section 214. The stepped surface 701 of the discharge port 70 pre-tensions the overflow seat element 85, the intermediate element 81, and the discharge seat element 71 towards the pressurization chamber 200. Accordingly, the overflow seat element 85, the intermediate element 81, and the discharge seat element 71 are in contact with each other, and movements of the respective elements 85, 81, and 71 in the axial direction are regulated.Furthermore, the inner projection 722 and the outer projection 723 of the discharge seat element 71 are pressed against the step surface between the discharge hole section 214 and the discharge hole section 215, i.e., the periphery of the discharge hole section 215 on the bottom surface of the discharge hole section 214. Accordingly, an axial force originating from the inner projection 722 and the outer projection 723 towards the pressurization chamber 200 acts on the periphery of the discharge hole section 215 on the bottom surface of the discharge hole section 214.

[0159] The discharge port 70 includes a polygonal columnar surface 703. The polygonal columnar surface 703 has a substantially hexagonal columnar shape. The polygonal columnar surface 703 is located in the axial direction of the outer peripheral wall of the discharge port 70 at a position radially outside the step surface 701. A tool adapted to the polygonal columnar surface 703 of the discharge port 70 can be used to screw the discharge port 70 into the discharge hole section 214 of the upper housing 21. In this case, the discharge port 70 is screwed into the discharge hole section 214 in a relatively simple manner.

[0160] The weld ring 709 is located outside the cover 26 and radially outside the discharge port 70. The weld ring 709 has a substantially cylindrical shape and is, for example, made of metal. The weld ring 709 is designed such that one end of the weld ring 709, which is arranged facing the pressurization chamber 200, extends radially outwards and comes into contact with a periphery of the cover hole section 267 of the flat section 281 of the outer peripheral wall 280 of the cover. The end of the weld ring 709, which is arranged facing the pressurization chamber 200, is welded to the flat section 281 of the outer peripheral wall 280 of the cover in the circumferential direction over its entire area.A section of the weld ring 709, which is located facing away from the pressurization chamber 200, is welded circumferentially to the outer peripheral wall of the discharge port 70 over its entire area. This configuration reduces fuel leakage from the fuel chamber 260 through a gap between the cover hole section 267 and the outer peripheral wall of the discharge port 70 to the outside of the cover 26.

[0161] The high-pressure fuel pipe 8 is connected to the end of the discharge port 70, which is located away from the pressurization chamber 200. In this configuration, the fuel, which has entered the fuel chamber 260 from the supply fuel pipe 7 via the supply passage 29 of the high-pressure pump 10, is pressurized in the pressurization chamber 200 and discharged via the discharge passage 705 within the discharge port 70 into the high-pressure fuel pipe 8. The high-pressure fuel discharged into the high-pressure fuel pipe 8 is supplied to the fuel distributor 137 via the high-pressure fuel pipe 8.

[0162] The discharge valve 75 is arranged between the discharge seat element 71 and the intermediate element 81. The discharge valve 75 is made of metal, for example. The discharge valve 75 includes a discharge valve contact section 76 and a discharge valve sliding section 77.

[0163] The discharge valve contact section 76 is essentially disc-shaped. An outer diameter of the discharge valve contact section 76 is smaller than an inner diameter of the discharge recess 721 and larger than an inner diameter of the intermediate recess 821. The discharge valve contact section 76 is arranged within the discharge recess 721 such that an outer edge of a surface of the discharge valve contact section 76 can contact the discharge valve seat 74 or be arranged separately from the discharge valve seat 74.

[0164] When the drain valve contact section 76 is separated from the drain valve seat 74, the drain valve 75 is open and allows fuel to flow into the drain hole 73. When the drain valve contact section 76 contacts the drain valve seat 74, the drain valve 75 is closed and restricts the fuel flow into the drain hole 73.

[0165] The discharge valve sliding section 77 is integrally formed with the discharge valve contact section 76. The discharge valve sliding section 77 projects from the other surface of the discharge valve contact section 76 and has a substantially cylindrical shape. The discharge valve sliding section 77 is substantially coaxial with the discharge valve contact section 76. The outer diameter of the discharge valve sliding section 77 is slightly smaller than the inner diameter of the intermediate recess 821.

[0166] The discharge valve 75 is movable in the axial direction, while an outer peripheral wall of the discharge valve sliding section 77 slides on an inner peripheral wall of the intermediate recess 821. The end of the discharge valve sliding section 77 facing away from the discharge valve contact section 76 can contact an outer edge of a bottom surface of the intermediate recess 821 or be separated from the outer edge of the bottom surface of the intermediate recess 821. The intermediate element 81 is able to regulate the movement of the discharge valve 75 in the opening direction when the discharge valve sliding section 77 of the discharge valve 75 contacts the bottom surface of the intermediate recess 821.

[0167] Holes 771 are formed in the discharge valve sliding section 77. The holes 771 extend through the discharge valve sliding section 77 between the inner peripheral wall and the outer peripheral wall of the discharge valve sliding section 77. Each of the holes 771 has a substantially cylindrical shape. The holes 771 are formed at equal intervals in the circumferential direction of the discharge valve sliding section 77. According to the present embodiment, the majority of holes 771 are four holes 771. The holes 771 fluidically connect a space inside the discharge valve sliding section 77 with a space outside the discharge valve sliding section 77. Accordingly, the discharge valve 75 is able to move back and forth freely in the axial direction.At least a portion of the holes 771 are themselves in a state in which the drain valve 75 is in contact with the bottom surface of the intermediate recess 821 of the intermediate element 81, between the pressurization chamber 200 and the end surface of the intermediate element 81 facing the pressurization chamber 200. Accordingly, at least a portion of the holes 771 are located between the pressurization chamber 200 and the end surface of the intermediate element 81 facing the pressurization chamber 200 in order to fluidly connect the space inside the drain valve sliding section 77 and the space outside the drain valve sliding section 77, regardless of the position of the drain valve 75, in a region where the drain valve 75 is movable between the drain seat element 71 and the intermediate element 81.

[0168] The spring 79, for example, is a coil spring and is arranged within the discharge valve sliding section 77. One end of the spring 79 is in contact with a recessed spring seat formed at the center point of a bottom surface of the intermediate recess 821, while the other end is in contact with the end surface of the valve contact section 76, which faces the discharge valve sliding section 77. The spring 79 biases the discharge valve 75 towards the discharge valve seat 74.

[0169] When the fuel pressure in the pressurization chamber 200 rises to a predetermined value or higher, the discharge valve 75 moves towards the high-pressure fuel pipe 8, while the latter resists a preload force of the spring 79. In this case, the discharge valve 75 is separated from the discharge valve seat 74 and open. Accordingly, the fuel flowing between the discharge seat element 71 and the pressurization chamber 200 flows through the discharge hole 73, the discharge valve seat 74, the discharge recess 721, the first passages 83, the annular recess 800, and the second passages 89 towards the high-pressure fuel pipe 8.

[0170] The overflow valve 91 is arranged within the cylindrical section 861 of the overflow element. The overflow valve 91 is made of metal, for example. The overflow valve 91 includes an overflow valve contact section 92, an overflow valve sliding section 93, and a protruding section 94 of the overflow valve.

[0171] The overflow valve contact section 92 has a substantially cylindrical shape. The overflow valve contact section 92 has a tapered shape such that an outer peripheral wall at one end of the overflow valve contact section 92 tapers axially towards the axis. The overflow valve contact section 92 is arranged such that one end can contact the overflow valve seat 88 or be separated from the overflow valve seat 88.

[0172] When the bypass valve contact section 92 is separated from the bypass valve seat 88, the bypass valve 91 is open and allows fuel to flow into the bypass hole 87. When the bypass valve contact section 92 contacts the bypass valve seat 88, the bypass valve 91 is closed and restricts the fuel flow into the bypass hole 87.

[0173] The overflow valve sliding section 93 has a substantially cylindrical shape. The overflow valve sliding section 93 is integrally formed with the overflow valve contact section 92 such that one end of the overflow valve sliding section 93 is connected to the other end of the overflow valve contact section 92. The overflow valve sliding section 93 is substantially coaxial with the overflow valve contact section 92. An outer diameter of the overflow valve sliding section 93 is slightly smaller than an inner diameter of the cylindrical section 861 of the overflow element. An outer peripheral wall of the overflow valve sliding section 93 is able to slide on an inner peripheral wall of the cylindrical section 861 of the overflow element.

[0174] If the gap between the outer peripheral wall of the bypass valve sliding section 93 and the inner peripheral wall of the cylindrical section 861 of the bypass element is excessively large, the fuel pressure can be reduced through the gap. In this case, the bypass valve 91 may be closed. According to the present embodiment, the size of the gap is therefore adjusted such that the fuel pressure is not reduced through the gap.

[0175] The overflow valve sliding section 93 has a tapered shape such that an outer peripheral wall of one end of the overflow valve sliding section 93, which is arranged facing the overflow valve contact section 92, tapers in a direction towards the axis of the overflow valve contact section 92. When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the lateral overflow hole 852 of the overflow seat element 85 is closed by the outer peripheral wall of the overflow valve sliding section 93 (compare Fig. 6).

[0176] The projecting section 94 of the overflow valve has a substantially cylindrical shape. The projecting section 94 of the overflow valve is integrally formed with the overflow valve sliding section 93 such that one end of the projecting section 94 of the overflow valve is connected to the center point of the end surface of the overflow valve sliding section 93, which is located away from the overflow valve contact section 92. The projecting section 94 of the overflow valve is substantially coaxial with the sliding section 93 of the overflow valve. The outer diameter of the projecting section 94 of the overflow valve is smaller than the outer diameter of the overflow valve sliding section 93.When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the end surface of the protruding section 94 of the overflow valve, which is arranged facing the pressurization chamber 200, is located between the overflow element bottom section 862 and the end surface of the cylindrical section 861 of the overflow element, which is arranged facing the pressurization chamber 200 (compare . Fig. 6).

[0177] The stop element 95 has a substantially cylindrical shape and is, for example, made of metal. The outer diameter of the stop element 95 is slightly larger than the inner diameter of the cylindrical section 861 of the overflow element. The stop element 95 is arranged within the cylindrical section 861 of the overflow element such that an outer peripheral wall of the stop element 95 fits against an inner peripheral wall of the cylindrical section 861 of the overflow element. In other words, the stop element 95 is substantially coaxial with the cylindrical section 861 of the overflow element. The stop element 95 is positioned in the axial direction of the cylindrical section 861 of the overflow element near the end of the cylindrical section 861 of the overflow element that faces the pressurization chamber 200. A gap is formed between the stop element 95 and the intermediate element 81.

[0178] The inner diameter of the stop element 95 is larger than the outer diameter of the projecting section 94 of the overflow valve. When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the end surface of the projecting section 94 of the overflow valve, which faces the pressurization chamber 200, is located within the stop element 95 (see Figure 1). Fig. 6) A substantially cylindrical gap is formed between the inner peripheral wall of the stop element 95 and the outer peripheral wall of the projecting section 94 of the overflow valve. Accordingly, the inner peripheral wall of the stop element 95 and the outer peripheral wall of the projecting section 94 of the overflow valve do not slide against each other.

[0179] The overflow valve 91 is arranged such that the outer peripheral wall of the overflow valve sliding section 93 can move back and forth in the axial direction while sliding on the inner peripheral wall of the cylindrical section 861 of the overflow element. The end of the projecting section 94 of the overflow valve, which is located away from the overflow valve sliding section 93, can contact the end surface of the intermediate element 81, which is located facing the overflow seat element 85, or be located separately from the end surface of the intermediate element 81, which is located facing the overflow seat element 85. The intermediate element 81 is able to regulate the overflow valve 91 such that it does not move in the opening direction when the projecting section 94 of the overflow valve is in contact with the intermediate element 81.

[0180] When the overflow valve contact section 92 is separated from the overflow valve seat 88 by a predetermined distance, the closure of the lateral overflow hole 852 by the outer peripheral wall of the overflow valve sliding section 93 is lifted. Accordingly, the overflow hole 87 is connected to the fuel chamber 260 via the lateral overflow hole 852, the outer peripheral overflow recess 851 and the lateral hole section 702.

[0181] When the overflow valve 91 moves back and forth in the axial direction within the cylindrical section 861 of the overflow element, it is possible for the fuel to flow back and forth within the cylindrical section 861 of the overflow element via the lateral hole 853 between the cylindrical section 861 of the overflow element and the outer peripheral overflow recess 851. Accordingly, the overflow valve 91 is able to move back and forth in the axial direction without interference.

[0182] The spring 99, for example, is a coil spring and is arranged radially outside the projecting section 94 of the overflow valve. One end of the spring 99 is in contact with the outer edge of the end surface of the overflow valve sliding section 93, which faces the pressurization chamber 200, and the other end is in contact with the end surface of the stop element 95, which faces away from the pressurization chamber 200. The stop element 95 thus stops the other end of the spring 99. The spring 99 biases the overflow valve 91 towards the overflow valve seat 88.

[0183] According to the present embodiment, an inner peripheral section of one end of the spring 99 is guided through an outer peripheral wall of the end of the projecting section 94 of the overflow valve, which is arranged facing the overflow valve sliding section 93. An inner peripheral wall of the cylindrical section 861 of the overflow element is designed such that an inner diameter of a section of the cylindrical section 861 of the overflow element, which is located between the pressurization chamber 200 and a sliding section of the cylindrical section 861 of the overflow element on the overflow valve sliding section 93, is larger than an inner diameter of the sliding section (compare Fig. 6) This configuration reduces contact between the outer peripheral section of the spring 99 and the inner peripheral wall of the cylindrical section 861 of the overflow element, thereby stabilizing the behavior of the spring 99 and the overflow valve 91.

[0184] If the fuel pressure in the discharge passage on one side of the overflow element base section 862, which faces the high-pressure fuel pipe 8, rises to an abnormal value, the overflow valve 91 moves towards a pressurization chamber 200 while resisting the preload force of the spring 99. As a result, the overflow valve 91 is separated from the overflow valve seat 88 and opened. The fuel in the discharge passage 705 on one side of the overflow element base section 862, which faces the high-pressure fuel pipe 8, is then returned to the fuel chamber 260 via the overflow hole 87, the lateral overflow hole 852, the outer peripheral overflow recess 851, and the lateral hole section 702. This operation of the overflow valve 91 prevents an abnormal increase in the fuel pressure flowing in the high-pressure fuel pipe 8.

[0185] According to the present embodiment, the fuel is not sent to the pressurization chamber 200, which is a high-pressure side, but to the fuel chamber 260, which is a low-pressure side, if the fuel in the discharge passage 705 on a side of the overflow element bottom section 862, which faces the high-pressure fuel pipe 8, has an abnormal pressure value, as described above.

[0186] According to the present embodiment, the flow path area of ​​the lateral orifice section 702 is larger than the flow path area of ​​the overflow orifice 87 in the state in which the overflow valve 91 is fully open. The flow path area of ​​the lateral overflow orifice 852 varies in accordance with the position of the overflow valve sliding section 93 relative to the lateral overflow orifice 852. Accordingly, the lateral overflow orifice 852 acts as a variable orifice. According to the present embodiment, the flow path area of ​​the lateral orifice section 702 on the downstream side of the lateral overflow orifice 852, which acts as a variable orifice, is larger than the flow path area of ​​the overflow orifice 87 on the upstream side of the lateral overflow orifice 852.Accordingly, the fuel pressure can be quickly reduced and stabilized at a lower pressure value if the fuel pressure on one side of the discharge passage 705, which is located facing the high-pressure fuel pipe 8, becomes abnormally high.

[0187] According to the present embodiment, the discharge seat element 71, the intermediate element 81 and the overflow seat element 85 are arranged in this order starting from the pressurization chamber 200 towards the outside (compare Fig. 6) In this case, the discharge valve 75 is arranged between the pressurization chamber 200 and the overflow valve 91. Accordingly, a dead volume associated with the pressurization chamber 200 can be reduced.

[0188] According to the present embodiment, the discharge port 70, the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75, the spring 79, the overflow valve 91, the spring 99 and the stop element 95 are integrally pre-assembled into the sub-assembly that forms the discharge passage section 700.

[0189] The steps for assembling the discharge passage section 700 are described below.

[0190] The overflow valve 91 and the spring 99 are initially inserted into the overflow seat element 85. Subsequently, the stop element 95 is fitted or pressed into the inner peripheral wall of the overflow seat element 85 to control a valve opening pressure.

[0191] Next, the overflow seat element 85, to which the overflow valve 91, the spring 99 and the stop element 95 are attached, is inserted into the discharge port 70. Subsequently, the intermediate element 81 is inserted into the discharge port 70.

[0192] The spring 79 and the drain valve 75 are then positioned in the intermediate recess 821 of the intermediate element 81. Subsequently, the drain seat element 71 is fitted or press-fitted into the inner peripheral wall of the drain port 70.

[0193] The assembly of the discharge passage section 700, i.e., a sub-assembly of the discharge passage section 700, is completed in the preceding manner. In the state of a sub-assembly of the discharge passage section 700, the discharge port 70 is housed within the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75, the spring 79, the overflow valve 91, the spring 99, and the stop element 95. Additionally, the stepped surface 701 of the discharge port 70, the overflow seat element 85, the intermediate element 81, and the discharge seat element 71 are in contact with one another.

[0194] As in the Fig. As shown in Figures 2 to 4, the central axis Axc1 of the electromagnetic drive unit 500 and the central axis Axc2 of the discharge passage section 700 lie on the same plane. This configuration reduces the increase in the size of the high-pressure pump 10 in the direction of the axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder 23. The central axis Axc1 of the electromagnetic drive unit 500 coincides with the axis of the cylindrical element 51. The central axis Axc2 of the discharge passage section 700 coincides with the axis of the discharge port 70.

[0195] According to the present embodiment, the high-pressure pump 10 further comprises a pulsation dampener 15, a support element 16, an upper support 171, and a lower support 172. The pulsation dampener 15 is manufactured, for example, by combining two thin metal plates, each having a circular disc shape, and joining the outer edges of the two plates by welding. A gas, such as nitrogen or argon, at a predetermined pressure is filled into the pulsation dampener 15.

[0196] The support element 16 has a cylindrical shape with a base and is made, for example, of metal. The support element 16 is positioned in the fuel chamber 260 such that an outer edge of the base section of the support element 16 comes into contact with an outer edge of the cover base section 262, and that an outer peripheral wall of a cylindrical section of the support element 16 comes into contact with an inner peripheral wall of the columnar cover section 261. A hole section formed at the center point of a base section of the support element 16 extends through the base section in the plate thickness direction.

[0197] Both the upper support 171 and the lower support 172 are ring-shaped and made of metal, for example. The pulsation damper 15 is sandwiched between the outer edges of the upper support 171 and the lower support 172 such that the respective outer edges of the upper support 171 and the lower support 172 are in contact with an outer edge of the pulsation damper 15. The outer edges of the upper support 171 and the lower support 172 are welded together. In this way, the pulsation damper 15, the upper support 171, and the lower support 172 are pre-assembled into a single unit, forming a sub-assembly that constitutes a damper unit 170.

[0198] The damper unit 170 is positioned between the upper housing 21 and the support element 16 such that the upper support 171 contacts the base of the support element 16 and the lower support 172 contacts a surface of the upper housing 21 facing the cover base section 262. The support element 16, the upper support 171, and the lower support 172 support the pulsation damper 15 in the fuel chamber 260. The lower support 172 is located in a recess formed in the end surface of the upper housing 21 facing away from the lower housing 22. The support element 170 increases the stiffness of the cover 26 and contributes to the reduction of NV (non-vibration). A plurality of holes are formed circumferentially in the lower support 172 to distribute fuel above and below the pulsation damper 15 through the holes.

[0199] In the present embodiment, the cover 26 covers the respective joining sections such that a joining section between the cylinder 23 and the upper housing 21, which forms the pressurization chamber 200, a joining section between the upper housing 21 and the cylindrical element 51, and a joining section between the upper housing 21 and the discharge port 70 are located in the fuel chamber 260. Accordingly, high-pressure fuel can be retained in the fuel chamber 260 even if fuel leaks out from the pressurization chamber 200.

[0200] A "high-pressure chamber," pressurized by the sliding of the plunger 11 and extending from the valve element 40 to the discharge valve 75, is defined by the cylinder 23, the upper housing 21, the stopper 35, the valve element 40, and the discharge seat element 71. A "low-pressure chamber" is defined by the lower housing 22, the cover 26, the weld rings 519 and 709, the outer peripheral surface of the discharge port 70, the seal holder 14, and the seal 141, such that the low-pressure chamber covers the "high-pressure chamber." Accordingly, fuel in the "high-pressure chamber" does not flow to the outside through a connection with the "low-pressure chamber," even if fuel leaks from the "high-pressure chamber." The "low-pressure chamber" and the outside are sealed by welding. Therefore, no fuel leaks to the outside.The "high-pressure chamber" is sealed by a tightening force generated by the screws of the cylindrical element 51 and the discharge port 70. Accordingly, an excessive external force generated by the high pressure does not act on a welded section that seals the "low-pressure chamber" and the outside.

[0201] Next, cylinder 23 of the present embodiment will be described in more detail.

[0202] As in the Fig. As shown in Figures 7 to 9, the cylinder 23 has a tapered surface 234, an outer peripheral recess 235 and an outer peripheral recess 236.

[0203] The tapered surface 234 is formed at the end of the intake hole 232 that faces away from the pressurization chamber 200. The tapered surface 234 tapers in a direction away from the pressurization chamber 200 and away from the axis of the intake hole 232.

[0204] The cylindrical inner peripheral wall 230, which is the inner peripheral wall of the cylindrical hole section 231, has, in addition to the sliding surface 230a and the surface 230b with increased diameter, inner tapered surfaces 230c and 230d. The inner tapered surface 230c connects the sliding surface 230a and the surface 230b with increased diameter. The inner tapered surface 230c tapers away from the axis Ax1 in a direction from the sliding surface 230a towards the surface 230b with increased diameter.

[0205] The inner tapered surface 230d connects the sliding surface 230a and an opening in the cylindrical inner peripheral wall 230. The inner tapered surface 230d tapers in a direction away from the axis Ax1, starting from the sliding surface 230a and moving towards the opening in the cylindrical inner peripheral wall 230.

[0206] As in Fig. As shown in Figure 9, the end facing away from the small-diameter section 112 of the outer peripheral wall of the large-diameter section 111 of the plunger 11 is located, regardless of the plunger 11's position, in the region extending from bottom dead center to top dead center between the enlarged-diameter surface 230b and the end of the sliding surface 230a facing the enlarged-diameter surface 230b. The end facing the small-diameter section 112 of the outer peripheral wall of the large-diameter section 111 of the plunger 11 is located on one side of the end of the sliding surface 230a opposite the enlarged-diameter surface 230b, which faces away from the enlarged-diameter surface 230b.Accordingly, the sliding surface 230a is able to slide on the outer peripheral wall of the large diameter section 111 in the entire axial range, regardless of the position of the plunger 11.

[0207] In a state where the plunger 11 is positioned within the cylindrical inner peripheral wall 230, an annular gap is formed between the outer peripheral wall of the large-diameter section 111 of the plunger 11 and the inner tapered surface 230c and the inner tapered surface 230d. Accordingly, during a reciprocating motion of the plunger 11 within the cylindrical inner peripheral wall 230, the fuel is guided in this gap between the outer peripheral wall of the large-diameter section 111 and the sliding surface 230a. This configuration readily forms an oil film between the outer peripheral wall of the large-diameter section 111 and the sliding surface 230a, thereby reducing uneven wear and abrasion between the outer peripheral wall of the large-diameter section 111 and the sliding surface 230a.

[0208] Angles formed by each of the inner tapered surfaces 230c and 230d and the axis Ax1 and the outer peripheral wall of the large-diameter section 111 are, for example, set to 10 degrees or less. Corners at both ends of the large-diameter section 111 of the plunger 11 in the axial direction are chamfered.

[0209] The outer peripheral recess 235 and the outer peripheral recess 236 are each radially recessed inwards to a predetermined depth, starting from the outer peripheral wall of the cylinder 23. The outer peripheral recess 235 is formed in a region that encompasses the entire intake port 232, i.e., the tapered surface 234 in the circumferential direction of the cylinder 23. The outer peripheral recess 235 is formed at a predetermined distance in the axial direction of the cylinder 23, as viewed in the axial direction of the intake port 232, in a region extending from a position on one side of the axis of the intake port 232 slightly towards the bottom section of the cylinder 23 to a position extending from a lower end of the tapered surface 234 away from the bottom section of the cylinder 23.The outer peripheral recess 235 is configured such that it has a substantially rectangular shape, as viewed in the axial direction of the intake hole 232. At least part of the outer peripheral recess 235 is formed in a region that overlaps the sliding surface 230a in the axial direction in a lower section of the cylinder 23, as viewed in the axial direction of the intake hole 232 (compare ). Fig. 7).

[0210] The outer peripheral recess 236 is formed in a region that encompasses the entire discharge hole 233 in the circumferential direction of the cylinder 23. The outer peripheral recess 236 extends by a predetermined distance in the axial direction of the cylinder 23, as viewed in the axial direction of the discharge hole 233, in a region extending from a position on one side of the axis of the discharge hole 233 slightly towards the bottom section of the cylinder 23 to a position extending from the lower end of the discharge hole 233 away from the bottom section of the cylinder 23. The outer peripheral recess 236 is designed such that it has a substantially rectangular shape, as viewed in the axial direction of the discharge hole 233.At least part of the outer peripheral recess 236 is formed in an area which overlaps in the axial direction with the sliding surface 230a in a lower section of the cylinder 23, as viewed in the axial direction of the discharge hole 233 (compare . Fig. 8).

[0211] The outer peripheral recesses 235 and 236 allow a section adapted to the upper housing 21, i.e., a shrink-fit section, in an axially upper section of the cylinder 23, as viewed in the axial direction of the intake port 232 or the exhaust port 233 (compare the Fig. 7 and Fig. 8).

[0212] As described above, an axial force acts in one direction, originating from the stepped surface between the small-diameter stopper section 36 and the large-diameter stopper section 37, towards the pressurization chamber 200, on the stepped surface between the intake port section 213 and the intake port section 212, when the cylindrical element 51 of the electromagnetic drive unit 500 is screwed into the intake port section 212 of the upper housing 21. Accordingly, the inner peripheral wall of the port section 211 of the upper housing 21 may be slightly radially deformed inwards around the intake port section 213. In contrast, according to the present embodiment, the outer peripheral recess 235 is formed in a position corresponding to the intake port section 213 of the outer peripheral wall of the cylinder 23.Accordingly, the surface pressure generated by the deformation and acting on the outer peripheral wall of the cylinder 23 can be reduced, even if the inner peripheral wall of the bore section 211 of the upper housing 21 is deformed radially inwards. In this way, radial inward deformation of the cylindrical inner peripheral wall 230 of the cylinder bore section 231 can be reduced. Consequently, a constant gap between the cylindrical inner peripheral wall 230 and the outer peripheral wall of the tappet 11 can be maintained, thus reducing uneven wear and abrasion between the cylindrical inner peripheral wall 230 and the outer peripheral wall of the tappet 11.

[0213] Furthermore, the inner peripheral wall of the hole section 211 of the upper housing 21 is deformed radially inwards as an effect of the axial force described above. Accordingly, an increase in the pressure of the pressurization chamber 200 can be easily managed by an increase in the surface pressure generated at the boundary of the outer peripheral recess 235 of the cylinder 23.

[0214] When the discharge port 70 of the discharge passage section 700 is screwed into the discharge hole section 214 of the upper housing 21, an axial force, generated from the inner projection 722 and the outer projection 723 towards the pressurization chamber 200, acts on the periphery of the discharge hole section 215 in the bottom surface of the discharge hole section 214. Accordingly, the inner peripheral wall of the hole section 211 of the upper housing 21 may be slightly radially deformed inwards around the discharge hole section 215. However, according to the present embodiment, the outer peripheral recess 236 is formed in a position corresponding to the discharge hole section 215 of the outer peripheral wall of the cylinder 23.Accordingly, the surface pressure generated by the deformation and acting on the outer peripheral wall of the cylinder 23 can be reduced, even if the inner peripheral wall of the bore section 211 of the upper housing 21 is deformed radially inwards. In this way, radial inward deformation of the cylindrical inner peripheral wall 230 of the cylinder bore section 231 can be reduced. Consequently, a constant gap between the cylindrical inner peripheral wall 230 and the outer peripheral wall of the tappet 11 can be maintained, thus reducing uneven wear and abrasion between the cylindrical inner peripheral wall 230 and the outer peripheral wall of the tappet 11.

[0215] Furthermore, the inner peripheral wall of the hole section 211 of the upper housing 21 is deformed radially inwards as an effect of the axial force described above. Accordingly, an increase in the pressure of the pressurization chamber 200 can be easily managed by an increase in the surface pressure generated at the boundary of the outer peripheral recess 236 of the cylinder 23.

[0216] Next, the assembly of the high-pressure pump 10 will be described.

[0217] The high-pressure pump 10, for example, is assembled in the following steps.

[0218] The cylinder 23 is initially inserted into the hole section 221 of the lower housing 22.

[0219] The cylinder 23, together with the lower housing 22, is then inserted into the bore section 211 of the upper housing 21 such that the intake port 232 is positioned corresponding to the intake port section 213, and the exhaust port 233 is positioned corresponding to the exhaust port section 215. The cylinder 23 is inserted into the bore section 211 while the upper housing 21 is preheated to increase its inner diameter. When the upper housing 21 is cooled, the inner diameter of the bore section 211 is reduced to allow the cylinder 23 to be fastened between the upper housing 21 and the cylinder 23. Similarly, an outer diameter section of the lower housing 22 is fixed to the upper housing 21 by a reduction in the inner diameter of the upper housing 21 on the lower side.In other words, the cylinder 23 and the lower housing 22 are fixed to the upper housing 21 by shrink fitting or cold fitting. At this point, the lower housing 22 is stopped between the upper end of the outermost diameter of the cylinder 23 and the lower end of the upper housing 21. In this case, the positions of the upper housing 21, the lower housing 22, and the cylinder 23 are defined in the vertical direction, and the upper housing 21, the lower housing 22, and the cylinder 23 are assembled into a single unit.

[0220] The stopper 35 is then inserted into the intake port section 213 and the intake port section 212. The spring 39 is then positioned in the stopper recess 352, and the valve element 40 is positioned in the stopper recess 351. Next, the seat element 31 is press-fitted to the side of the stopper 35 of the intake port section 212 that faces away from the pressurization chamber 200, and both end surfaces of the stopper 35 are brought into contact with a recess in the upper housing 21 and the seat element 31. The sliding section 430 of the valve element 40 overlaps with the inner peripheral wall of the stopper recess 351 when the spring 39 is at its natural length. The assembly is thus improved.

[0221] The damper unit 170, which includes the pulsation damper 15, the upper support 171 and the lower support 172, is arranged in the recess of the upper housing 21, i.e. on a side of the upper housing which is located away from the lower housing 22.

[0222] The cover 26, on which the support element 16 was previously provided, is attached to cover the upper housing 21. The cover 26 is arranged such that the cover hole section 266 is positioned corresponding to the intake hole section 212, and the cover hole section 267 is positioned corresponding to the exhaust hole section 214.

[0223] The first electromagnetic drive unit 501, in a subassembly state, is then inserted into the cover hole section 266, and the cylindrical element 51 is screwed into the intake hole section 212 of the upper housing 21. At this time, the cylindrical element 51 is screwed into the intake hole section 212 using a tool (not shown) corresponding to the second column-shaped section 512 of the cylindrical element 51. In this case, an axial force acts between the intake hole section 212 and the intake hole section 213 of the upper housing 21, originating from the cylindrical element 51 and extending towards the pressurization chamber 200, on the seat element 31, the stopper 35, and the stepped surface of the upper housing.

[0224] The discharge passage section 700 is then inserted into the cover hole section 267 in a subassembly state, and the discharge port 70 is screwed into the discharge hole section 214 of the upper housing 21. At this time, the discharge port 70 is screwed into the discharge hole section 214 using a tool (not shown) corresponding to the polygonal columnar surface 703 of the discharge port 70. In this case, an axial force acts from the stepped surface 701 of the discharge port 70 towards the pressurization chamber 200 on the overflow seat element 85, the intermediate element 81, the discharge seat element 71, and the stepped surface between the discharge hole section 214 and the discharge hole section 215 of the upper housing 21.

[0225] The end of the columnar cover section 261, which faces away from the cover base section 262, and the lower housing 22 are then completely welded together in the circumferential direction of the columnar cover section 261. The weld ring 709 is then arranged on the radial outer side of the discharge port 70. The weld ring 709, the outer peripheral wall 280 of the cover, and the outer peripheral wall of the discharge port 70 are completely welded together in the circumferential direction of the weld ring 709. The weld ring 519 is then arranged on the radial outer side of the first cylindrical section 511 of the cylindrical element 51. The welding ring 519, the outer peripheral wall 280 of the cover and the outer peripheral wall of the first cylindrical section 511 are completely welded together in the circumferential direction of the welding ring 519.

[0226] The seal 141, the column-shaped intermediate element 241, and the plunger 11 are then inserted into the seal holder 14 in that order and completely welded together circumferentially after the seal holder 14 has been assembled on the inside of the holder support 24. The oil seal 142 is mounted on the seal holder 14.

[0227] The sealing element 240 is then assembled onto the holder support 24. The spacer 140 is positioned on the seal holder 14. The spring 13 is located on one side of the seal holder 14 opposite the upper housing 21. The spring seat 12 is assembled onto the plunger 11.

[0228] Subsequently, one end of the feed passage section 29 is positioned in a location that is in contact with the outer peripheral section of the cover hole section 265 of the cover base section 262. The feed passage section 29 and the cover base section 262 are completely welded together in the circumferential direction of the feed passage section 29.

[0229] The second electromagnetic drive unit 502 is then provided in a sub-assembly state at the end of the first electromagnetic drive unit 501 opposite the pressurization chamber 200 such that the magnetic choke section 56 and the solid core 57 are located inside the coil 60. The second electromagnetic drive unit 502 is arranged such that the connector 65 faces away from the solid section 25 and is essentially parallel to the axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder 23.

[0230] The center point of the yoke 645 is then welded to the end surface 572 of the solid core 57, which faces away from the pressurization chamber 200. The assembly of the high-pressure pump 10 is completed by the preceding steps.

[0231] Next, the installation of the high-pressure pump 10 on the machine 1 will be described.

[0232] According to the present embodiment, the high-pressure pump 10 is attached to the machine 1 such that the mounting support 24 is inserted into the mounting hole section 3 of the machine head 2 (compare Fig. 2) The high-pressure pump 10 is fixed to the machine 1 by attaching the fixed section 25 to the machine head 2 using the bolts 100. The high-pressure pump 10 is mounted on the machine 1 in such a position that the axis Ax1 of the cylindrical inner peripheral wall 230 of the cylinder 23 extends in the vertical direction.

[0233] The high-pressure pump 10 is attached to the machine 1, for example, by the following steps. Initially, the lifter 5 is inserted into the mounting hole section 3 of the machine head 2. Subsequently, the mounting support 24 of the high-pressure pump 10 is inserted into the mounting hole section 3 of the machine head 2. The position of each of the bolt holes 250 of the fixed section 25 is adjusted such that it corresponds to the position of the corresponding fixing hole section 120 of the machine head 2.

[0234] The bolts 100 are then inserted into the bolt holes 250 to screw them into the fixing hole sections 120. At this time, the bolts 100 are screwed into the fixing hole sections 120 using a tool (not shown) corresponding to the head sections 102 of the bolts 100. In this way, the fixed section 25 is fixed to the machine head 2.

[0235] The installation of the high-pressure pump 10 on the machine 1 is completed by the preceding steps.

[0236] Next, an operation of the high-pressure pump 10 of the present embodiment will be described with reference to the Fig. 2 to 6 will be described. "Suction step"

[0237] During a stoppage of power supply to the coil 60 of the electromagnetic drive unit 500, the valve element 40 is biased towards the pressurization chamber 200 by the spring 54 and the needle 53. Accordingly, the valve element 40 is separated from the valve seats 310, i.e., the valve is open. When the plunger 11 moves away from the pressurization chamber 200 in this state, the volume of the pressurization chamber 200 increases. In this case, fuel from one side of the valve seats 310 opposite the pressurization chamber 200, i.e., fuel from the fuel chamber 260, is drawn into the pressurization chamber 200 via the communication path 33. "Quantity control process"

[0238] When the plunger 11 moves towards the pressurization chamber 200 in the open state of the valve element 40, the volume of the pressurization chamber 200 decreases. In this case, the fuel between the pressurization chamber 200 and the valve seats 310 is recirculated from the valve seats 310 to the fuel chamber 260. When power is supplied to the coil 60 during a quantity control step, the movable core 55, together with the needle 53, is drawn towards the fixed core 57. In this case, the valve element 40 is biased by the spring 39 to come into contact with the valve seats 310 and is closed. A quantity of fuel being returned from the pressurization chamber 200 to the fuel chamber 260 is controlled by closing the valve element 40 in accordance with a movement of the plunger 11 towards the pressurization chamber 200.As a result, the quantity of fuel pressurized in the pressurization chamber 200 is determined. The quantity control process for returning the fuel from the pressurization chamber 200 to the fuel chamber 260 is completed by closing the valve element 40.

[0239] If the fuel injectors 138 do not inject fuel, i.e., during an interruption of the fuel flow, the coil 60 is not energized. Consequently, no fuel is discharged from the high-pressure pump 10. The valve element 40 is in the open state at this time. Accordingly, the fuel moves back and forth between the pressurization chamber 200 and the fuel chamber 260 in accordance with a reciprocating motion of the plunger 11. “Pressure application process”

[0240] As the plunger 11 moves towards the pressurization chamber 200, with the valve element 40 closed, the volume of the pressurization chamber 200 decreases. As a result, the fuel in the pressurization chamber 200 is compressed and pressurized. When the pressure of the fuel in the pressurization chamber 200 becomes greater than or equal to the opening pressure of the discharge valve 75, the discharge valve 75 opens. In this case, the fuel is discharged from the pressurization chamber 200 towards the high-pressure fuel pipe 8, i.e., the fuel distributor 137.

[0241] When the plunger 11 moves away from the pressurization chamber 200 in this state by stopping the power supply to the coil 60, the valve element 40 opens again. In this way, the pressurization process for pressurizing the fuel is completed, and the intake process for drawing fuel from the fuel chamber 260 to the pressurization chamber 200 is restarted.

[0242] By repeating the preceding "suction process," "quantity control process," and "pressurization process," the high-pressure pump 10 pressurizes the fuel, which is drawn from the fuel chamber 260 into the pressurization chamber 200, and discharges it, supplying it to the fuel distributor 137. The quantity of fuel supplied from the high-pressure pump 10 to the fuel distributor 137 is controlled by the electromagnetic drive unit 500, which controls the timing, or similar, at which power is supplied to the coil 60.

[0243] When the plunger 11 moves back and forth in the open state of the valve element 40, such as during the "intake process" and "quantity control process" described above, a pressure pulsation can be generated in the fuel within the fuel chamber 260 in accordance with an increase and decrease in the volume of the pressurization chamber 200. The pulsation damper 15, which is provided in the fuel chamber 260, is able to reduce pressure pulsation of the fuel in the fuel chamber 260 by elastic deformation in accordance with a change in the fuel pressure in the fuel chamber 260.

[0244] Furthermore, during a reciprocating movement of the plunger 11 in accordance with an increase and decrease in the volume of the variable-volume chamber 201, a pressure pulsation can be generated. In this case, the pulsation damper 15, which is provided in the fuel chamber 260, is similarly able to reduce pressure pulsation of the fuel in the fuel chamber 260 by elastic deformation in accordance with a change in the fuel pressure in the fuel chamber 260.

[0245] As the plunger 11 moves downwards away from the pressurization chamber 200, the volume of the variable-volume chamber 201 decreases in accordance with the downward movement of the plunger 11. In this case, the fuel is forced towards the fuel chamber 260. As a result, the fuel in the fuel chamber 260 is easily introduced into the pressurization chamber 200 during the downward movement of the plunger 11. As the plunger 11 moves upwards towards the pressurization chamber 200, the volume of the variable-volume chamber 201 increases. In this case, the fuel being returned from the pressurization chamber 200 is easily discharged into the variable-volume chamber 201 during quantity control. Pulsation of the fuel chamber 260 is reduced by the functions described above.

[0246] As the tappet 11 moves back and forth, the volume of the variable-volume chamber 201 increases or decreases. In this case, the fuel flows back and forth between the fuel chamber 260 and the orifice section 222, the annular space 202, and the variable-volume chamber 201. Accordingly, a low-temperature fuel can cool the cylinder 23 and the tappet 11, which are heated to a high temperature by heat generated from sliding between the tappet 11 and the cylinder 23, and by heat generated by pressurizing the fuel in the pressurization chamber 200. Wear on the tappet 11 and the cylinder 23 can therefore be reduced.

[0247] A portion of the fuel, which is under high pressure in the pressurization chamber 200, flows through the space between the tappet 11 and the cylinder 23 into the variable-volume chamber 201. This creates an oil film between the tappet 11 and the cylinder 23, effectively reducing wear on both. The fuel flowing from the pressurization chamber 200 into the variable-volume chamber 201 is returned to the fuel chamber 260 via the annular space 202 and the perforated section 222.

[0248] <a-1>Next, the intake valve unit 300 will be described in detail.

[0249] As in the Fig. 10 and Fig. As shown in Figure 11, the seat element 31 essentially has a disc shape. The seat element 31 is arranged in the intake passage 216 within the intake bore section 212 such that the seat element 31 is essentially coaxial with the intake bore section 212. An outer peripheral wall of the seat element 31 is press-fitted into an inner peripheral wall of the intake bore section 212.

[0250] The seat element 31 includes the communication path 32, the communication paths 33, and valve seats 310. The communication path 32 passes through the seat element 31 at a midpoint between one surface and the other surface of the seat element 31. The communication path 32 is essentially coaxial with the seat element 31. An inner diameter of the communication path 32 is larger than an outer diameter of the end of the needle body 531, which faces the pressurization chamber 200. Accordingly, an essentially cylindrical space is formed between the inner peripheral wall of the communication path 32 and the outer peripheral wall of the needle body 531 such that the fuel can flow through the space.

[0251] Each of the communication paths 33 has a substantially cylindrical shape and passes through the seat element 31 between one surface and the other surface of the seat element 31. The communication paths 33 are located radially outside the communication path 32. In this embodiment, the twelve communication paths 33 are formed at equal intervals in the circumferential direction of the seat element 31. The arrangement of the communication paths 33 at equal intervals stabilizes the fuel flow and the behavior of the valve element 40. The communication paths 33 are arranged on a virtual circle VC11, which is centered on the axis of the seat element 31 (compare Fig. 11) The inner diameter of each of the communication paths 33 is smaller than the inner diameter of the communication path 32.

[0252] Communication path 32 corresponds to an “inner communication path”, while each of the communication paths 33 corresponds to an “outer communication path”.

[0253] The valve seats 310 are formed annularly around the communication path 32 and the plurality of communication paths 33 on a surface of the seat element 31 that faces the pressurization chamber 200. In other words, the valve seats 310 are formed on the surface of the seat element 31 that faces the pressurization chamber 200. More precisely, one of the valve seats 310 is located between the communication path 32 and the connecting holes 44, one of the valve seats 310 is located between the connecting holes 44 and the communication paths 33, and one of the valve seats 310 is located radially outside the communication paths 33. Accordingly, there are three valve seats 310. The three valve seats 310 are arranged concentrically.

[0254] The seat element 31 includes an annular recess 311. The annular recess 311 has a substantially ring-shaped form and extends from the end surface of the seat element 31, which faces the pressurization chamber 200, towards the cylindrical element 51. The annular recess 311 is located in the radial direction of the seat element 31 outside the communication paths 33. The annular recess 311 is substantially coaxial with the seat element 31 (compare the Fig. 10 and Fig. 11) In this way, the annular recess 311 is located in the radial direction of the seat element 31 outside the communication paths 33. Accordingly, the flowability of the fuel is improved during quantity control. Fuel pressure in the annular recess 311 is applied to the valve element 40 in the valve opening direction. Consequently, the valve closure can be reduced by dynamic pressure.

[0255] As in the Fig. 10 and Fig. As shown in Figure 12, the stopper 35 has the stopper section 36 with small diameter, the stopper section 37 with large diameter, the stopper recess 351, the stopper recess 352, the stopper projection 353, the connecting holes 38 and other features.

[0256] The small-diameter stopper section 36 has a substantially cylindrical shape. The outer diameter of the small-diameter stopper section 36 is slightly smaller than the inner diameter of the intake hole section 213. The large-diameter stopper section 37 also has a substantially cylindrical shape. The outer diameter of the large-diameter stopper section 37 is larger than the outer diameter of the small-diameter stopper section 36 and slightly smaller than the inner diameter of the intake hole section 212. The large-diameter stopper section 37 is integrally formed with the small-diameter stopper section 36 to be coaxial with a portion of the small-diameter stopper section 36 that faces away from the pressurization chamber 200.

[0257] The stopper 35 is arranged in the intake passage 216 such that the small-diameter stopper section 36 is located within the intake hole section 213, and the large-diameter stopper section 37 is located within the intake hole section 212. An annular stepped surface between the small-diameter stopper section 36 and the large-diameter stopper section 37 is in contact with an annular stepped surface between the intake hole section 212 and the intake hole section 213. This restricts the movement of the stopper 35 towards the pressurization chamber 200.

[0258] The surface of the large-diameter stopper section 37 of the stopper 35, which faces away from the pressurization chamber 200, is in contact with the surface of the seat element 31, which faces the pressurization chamber 200. This restricts the movement of the stopper 35 away from the pressurization chamber 200.

[0259] The stopper recess 351 extends from the surface of the large-diameter stopper section 37, which faces the seat element 31, towards the pressurization chamber 200. The stopper recess has a substantially cylindrical shape. The stopper recess 351 is substantially coaxial with the large-diameter stopper section 37. The inner diameter of the stopper recess 351 is smaller than the outer diameter of the large-diameter stopper section 37 and larger than the outer diameter of the small-diameter stopper section 36.

[0260] The stopper recess 352 extends from the bottom surface of the stopper recess 351 towards the pressurization chamber 200. The stopper recess 352 has a substantially cylindrical shape. The stopper recess 352 is substantially coaxial with the stopper recess 351. The inner diameter of the stopper recess 352 is smaller than the inner diameter of the stopper recess 351 and smaller than the outer diameter of the small-diameter stopper section 36. It should be noted that the bottom surface of the stopper recess 352 is closer to the pressurization chamber 200 than the step surface between the small-diameter stopper section 36 and the large-diameter stopper section 37.

[0261] The stopper projection 353 extends from the center of the bottom surface of the stopper recess 352 towards the seat element 31 and has a substantially cylindrical shape. The stopper projection 353 is substantially coaxial with the stopper recess 352. The end surface of the stopper projection 352, which faces the seat element 31, is located between the seat element 31 and the bottom surface of the stopper recess 351.

[0262] Each of the connecting holes 38 passes through the stopper 35 between the bottom surface of the stopper recess 352 and the surface of the small-diameter stopper section 36, which faces the pressurization chamber 200. The connecting holes 38 are located radially outside the stopper projection 353. The four connecting holes 38 are formed at equal intervals in a circumferential direction of the small-diameter stopper section 36. The connecting holes 38 are arranged on a virtual circle VC12 around an axis of the small-diameter stopper section 36 (compare Fig. 12). A diameter of the virtual circle VC12 is smaller than a diameter of the virtual circle VC11.

[0263] The intake passage 216 is defined in the communication path 32 and communication paths 33 of the seat element 31, the stopper recess 351 and stopper recess 352 of the stopper 35, and the connecting holes 38. This allows fuel in the fuel chamber 260 to enter the pressurization chamber 200 via the intake passage 216, which is formed in the communication path 32, the communication paths 33, the stopper recess 351, the stopper recess 352, the connecting holes 38, and the intake hole 232. Both the seat element 31 and the stopper 35 correspond to an "intake passage formation section".

[0264] As in Fig. As shown in Figure 10, the valve element 40 is arranged within the stopper recess 351. In other words, the valve element is located in the intake passage 216 between the pressurization chamber 200 and the seat element 31. As shown in the Fig. As shown in Figures 10 and 13 to 16, the valve element 40 includes the valve body 41, the tapered sections 42, the guide sections 43 and the connecting holes 44.

[0265] The valve body 41, the tapered sections 42, and the guide sections 43 are made of a metal such as stainless steel and are integrally formed together. The valve body 41 essentially has a disc shape.

[0266] Each of the tapered sections 42 has a substantially annular shape and is integrally formed with the valve body 41 on the radial outer surface of the valve body 41. Each of the tapered sections 42 has a tapered shape such that the surface of the tapered section 42 facing the pressurization chamber 200 tapers in a direction towards the pressurization chamber along the axis Ax2 (compare the Fig. 10, Fig. 15 and Fig. 16).

[0267] Each of the guide sections 43 projects radially outward from the valve body 41 to divide the tapered sections 42 circumferentially and is integrally formed with the valve body 41 and the tapered sections 42. According to the present embodiment, the three guide sections 43 are formed at equal intervals around the circumference of the valve body 41 to divide the three tapered sections 42 circumferentially. The end of each of the guide sections 43 facing away from the valve body 41 is located on the radial outer side of an outer edge of the tapered section 42 (compare the Fig. 13 and Fig. 14) The guide section 43 is able to guide an axial movement of the valve element 40 by means of a sliding section 430, which is formed at the end of the guide section 43 that is arranged away from the valve body 41, sliding on an inner peripheral wall of the stopper recess 351 of the stopper 35 as an intake passage forming section.

[0268] Each of the connecting holes 44 passes through the valve body 41 between one surface and the other surface of the valve body 41. The nine connecting holes 44 are formed at equal intervals in the circumferential direction of the valve body 41. The connecting holes 44 are arranged on a virtual circle VC1, which is centered on the axis Ax2 of the valve body 41 (compare the Fig. 13 and Fig. 14).

[0269] As in Fig. As shown in Figure 13, a boundary line B1 is formed between inner edges of the three tapered sections 42 and an outer edge of the valve body 41 along the concentric circle CC1, which corresponds to a virtual circle VC1.

[0270] As in Fig. As shown in Figure 3, three straight lines L11 extending from a center point of the valve body 41 to the respective centers of the three guide sections 43 define a first region T1, a second region T2, and a third region T3. The three connecting holes 44 are arranged in the first region T1, the second region T2, and the third region T3 of the valve body 41.

[0271] Assuming that the number h of connecting holes 44 is nine (h = 9), and that the number g of guide sections 43 is three (g = 3), the number of connecting holes 44 facing an inner edge of one of the tapered sections 42 separated by the guide sections 43 is three (h / g = 9 / 3 = 3).

[0272] Assuming that the three connecting holes 44 formed in the first region T1, the second region T2, and the third region T3 are a connecting hole 441, a connecting hole 442, and a connecting hole 443, arranged in that order in the circumferential direction of the virtual circle VC1, the boundary line B1 in the first region T1 is located between the inner edge of the tapered section 42 and the outer edge of the valve body 41, between a line of contact LT11, which is located closer to the third region T3 when there are two lines of contact between the outer edge of the connecting hole 441 of the first region T1 and the outer edge of the connecting hole 443 in the second region T2, which is symmetrical with respect to a straight line L11 between the first region T1 and the second region T2 with respect to the connecting hole 441 in the first region T1, and a line of contact LT11,which is located closer to the second region T2 at two lines of contact between the outer edge of the connecting hole 443 in the first region T1 and the outer edge of the connecting hole 441 in the third region T3, which is symmetrical to the connecting hole 443 in the first region T1 with respect to a straight line L11 between the first region T1 and the third region T3.

[0273] The boundary line B1 between the inner edge of the tapered section 42 in the second region T2 of the valve body 41 and the outer edge of the valve body 41 and the boundary line B1 in the third region T3 of the valve body 41 between the inner edge of the tapered section 42 and the outer edge of the valve body 41 are formed similarly to the boundary line B1 above.

[0274] In other words, according to the present embodiment, the boundary line B1 between the inner edge of one tapered section 42, which is sandwiched between the two guide sections 43, and the outer edge of the valve body 41 is in a region between the two lines of contact LT11 between the outer edges of the end connection holes (441, 443), which are two of the connection holes 44 located at both ends facing the inner edge of one of the tapered sections 42, and the outer edges of the connection holes 44 (443, 441), which are symmetrical with respect to a straight line L11 extending from the center of the valve body 41 to the center of the guide section 43, is formed with respect to the respective end connection holes (441, 443).

[0275] According to the present embodiment, both a surface 401 (a surface 401) of the valve element 40, i.e., the surface of the valve body 41 facing away from the pressurization chamber 200, the surface of the guide section 43 facing away from the pressurization chamber 200, and the surface of the tapered section 42 facing away from the pressurization chamber 200, have a flat shape and are formed on the common plane, as shown in Fig. Figure 10 shows that both a surface (the other surface) 402 of the valve element 40, i.e. the surface of the valve body 41 which is arranged facing the pressurization chamber 200, and the surface of the guide section 43 which is arranged facing the pressurization chamber 200, have a flat shape and are formed on the common plane.

[0276] According to the present embodiment, the plate thickness of the valve body 41 and the guide section 43 of the valve element 40, i.e., the distance between one surface 401 and the other surface 402 of the valve element 40, is smaller than the distance between the surface of the seat element 31 facing the pressurization chamber 200 and an end surface of the stopper projection 353 facing the seat element 31, as shown in Fig. 10 is shown.

[0277] One surface 401, which is the surface of the valve element 40 facing the seat element 31, is configured to come into contact with the surface of the seat element 31 facing the pressurization chamber 200 (i.e., the plurality of valve seats 310). The center point of the other surface 402, which is the surface of the valve element 40 facing the stopper 35, is configured to come into contact with the end surface of the stopper projection 353 facing the seat element 31.

[0278] The valve element 40 is able to move back and forth in the axial direction in a region of a difference DD1 between the plate thickness of the valve body 41 and the guide section 43, i.e. the distance between one surface 401 and the other surface 402 and the distance between the surface of the seat element 31 facing the pressurization chamber 200 and an end surface of the stopper projection 353 facing the side end surface of the seat element 31 of the stopper projection 353.

[0279] When the surface 401, which is the surface of the valve element 40 facing the seat element 31, is separated from the surface of the seat element 31 facing the pressurization chamber 200, i.e., the valve seats 310, the valve element 40 is open to allow fuel to flow in communication path 32 and communication paths 33. When the surface 401, which is the surface of the valve element 40 facing the seat element 31, comes into contact with the valve seats 310, the valve element 40 is closed to restrict fuel flow in communication paths 33.

[0280] When the valve element 40 is opened, fuel can flow between communication path 32 and communication paths 33, as well as stopper recess 351. This allows fuel to flow from the side of fuel chamber 260 via communication path 32, communication paths 33, stopper recess 351, stopper recess 352, connecting holes 38, and intake hole 232 to pressurization chamber 200. It also allows fuel to flow from pressurization chamber 200 via intake hole 232, connecting holes 38, stopper recess 352, stopper recess 351, communication paths 33, and communication path 32 to fuel chamber 260.At this time, the fuel flows through the connecting holes 44 of the valve element 40, the periphery of the valve element 40, the surface of the valve element 40 and the boundary line B1 between the inner edge of the tapered section 42 and the outer edge of the valve body 41.

[0281] When the valve element 40 is closed, the fuel flow between communication path 32 and communication paths 33, as well as stopper recess 351, is restricted. Accordingly, the fuel flow from the side of the fuel chamber 260 via communication path 32, communication paths 33, stopper recess 351, stopper recess 352, connecting holes 38, and intake hole 232 to the pressurization chamber 200 is restricted. The fuel flow from the side of the pressurization chamber 200 via intake hole 232, connecting holes 38, stopper recess 352, stopper recess 351, communication paths 33, and communication path 32 to the fuel chamber 260 is also restricted.

[0282] As in Fig. As shown in Figure 10, the spring 39 is arranged on the radial outer surface of the stopper projection 353. One end of the spring 39 is in contact with the bottom surface of the stopper recess 352, and the other end is in contact with the other surface 402, which is the surface of the valve element 40 facing the pressurization chamber 200. The spring 39 biases the valve element 40 towards the seat element 31.

[0283] The valve element 40 includes a plurality of sealing sections 410 formed at positions corresponding to the valve seats 310 located on the seat element 31. Each of the sealing sections 410 includes a first sealing section 411, which has an annular shape and seals between the communication path 32 (the inner communication path) and the connecting holes 44; a second sealing section 412, which has an annular shape and seals between the communication paths 33 (the outer communication path) and the connecting holes 44; and a third sealing section 413, which has an annular shape and seals between the communication paths 33 and a flow path 45 extending radially outward from the valve body 41 of the valve element 40 and formed between the valve body 41 and the stopper recess 351.

[0284] This section describes a relationship between the flow path surfaces of the communication path 32 and the communication paths 33 formed in the seat element 31 and the connecting holes 44 formed in the valve element 40.

[0285] In a state of contact between the valve element 40 and the stopper 35, i.e., during a full stroke, assuming that an area of ​​an annular flow path formed between a wall surface defined by a minimal circle covering all of the communication paths 33 formed on the wall surface of the seat element 31 facing the valve element 40 and a wall surface (third sealing section 413) of the valve element 40 is a first passage surface S1, that a total flow path area of ​​the communication paths 33 is a second passage surface S2, and an area of ​​an annular flow path between a wall surface (second sealing section 412) defined by a minimal circle covering all of the connection holes 44 formed on the surface of the valve element 40 facing the seat element 31,and the wall surface of the seat element 31 is a third flow path surface S3, the second passage surface S2 is larger than the total area of ​​the first passage surface S1 and the third flow path surface S3, as in the , Fig. 10 and Fig. 11 is shown.

[0286] Assuming that the area of ​​the annular flow path between the opening of the communication path 32, which is arranged facing the wall surface of the valve element 40, and the wall surface (the first sealing section 411) of the valve element 40 is a fourth flow path area S4, and that a total flow path area of ​​the connecting holes 44 formed in the valve element 40 is a fifth flow path area S5, the fifth flow path area S5 is larger than the total area of ​​the third flow path area S3 and the fourth flow path area S4.

[0287] Furthermore, the sixth flow path area S6 is larger than the fourth flow path area S4, assuming that a flow path area of ​​the communication path 32 in the seating element 31 is a sixth flow path area S6.

[0288] By adjusting the relationship between the flow path surfaces of the communication path 32 and the communication paths 33 formed in the seat element 31 and the connecting holes 44 formed in the valve element 40 to the preceding relationship, the flow path formed between the valve element 40 and the seat element 31 becomes a throttling path.

[0289] Next, the plate thickness of valve element 40 will be described.

[0290] As in Fig. As shown in Figure 10, the plate thickness of the valve body 41 of the valve element 40 is smaller than the plate thickness of the seat element 31. In this case, the valve body 41 deforms in accordance with the seat element 31, thus improving the sealing capacity. It is preferable for the valve body 41 to have a shape capable of generating a surface pressure, even during pressure application, which is then applied to the seat element 31.

[0291] According to the present embodiment, the maximum injection pressure of the fuel injected by the fuel injectors 138, i.e., the system fuel pressure of the fuel supply system 9, is 20 MPa or more. Accordingly, the pressure of the pressurization chamber 200 can increase to approximately 40 MPa due to pressure loss. To ensure sufficient strength and sealing capability of the valve element 40 under such a high-pressure environment, a plate thickness ratio t / D is preferably expressed by the following formula 1. 0.06≤t / D≤0.13

[0292] In the preceding formula 1, D is a diameter of the third sealing section 413, which seals between the flow path 45 radially outwards and the communication paths 33 (compare the Fig. 11 and Fig. 14). Additionally, t is a plate thickness of the valve body 41 (compare Fig. 10). In the present embodiment, t is, for example, 1 mm.

[0293] The significance of adjusting the plate thickness ratio t / D to the value expressed as the preceding formula 1 is explained with reference to Fig. 17 can be described. A graph of Fig. Figure 17 shows a relationship between the plate thickness ratio t / D, a sealing surface pressure (dash-dotted line) and a limiting pressure (material strength, dashed-dotted line).

[0294] If the plate thickness ratio t / D is 0.06 or greater, the desired material strength, i.e., approximately 40 MPa, which is a peak fuel pressure of the pressurization chamber 200, can be ensured, as shown in Fig. Figure 17 shows that if the plate thickness ratio t / D is 1.13 or less, a desired sealing surface pressure (40 MPa or higher) can be ensured.

[0295] The valve body 41 deforms in a high-pressure fuel environment, which is why the plate thickness t of the valve body 41 is preferably large to increase strength. However, the majority of flow paths do not need to be sealed if the valve element 40 has the majority of sealing sections 410, as in the present embodiment. In this case, sufficient sealing capability must also be ensured. To improve sealing capability, the thickness t must be reduced. According to the present embodiment, the plate thickness ratio t / D is therefore based on the graph shown in Fig. As shown in Figure 17, the plate thickness ratio t / D is set to the value expressed as Formula 1 above to improve sealing performance while ensuring the strength of the valve element 40. To further improve sealing performance, the plate thickness ratio t / D is preferably expressed as Formula 2 below to set the sealing surface pressure, for example, to 60 MPa or more. 0.06≤t / D≤0.12

[0296] As described above (A1), the high pressure pump 10 of the present embodiment includes the cylinder 23 as the pressurization chamber formation section, the upper housing 21 and the stopper 35 as the intake passage formation section, the seat element 31 and the valve element 40.

[0297] Cylinder 23 defines the pressurization chamber 200, into which fuel is pressurized. The upper housing 21 and the stopper 35 define the intake passage 216, through which fuel flows and is drawn into the pressurization chamber 200.

[0298] The seat element 31 is arranged in the intake passage 216 and includes the communication path 32, which passes through the seat element 31 between one surface and the other surface, and the communication paths 33, which pass through the seat element 31 between one surface and the other surface. The communication paths 33 are located radially outside the communication path 32. The valve element 40 is arranged between the pressurization chamber 200 and the seat element 31. The valve element 40 is capable of allowing fuel flow in the communication path 32 by disconnecting from the seat element 31 to open the communication path 32, and of restricting fuel flow in the communication path 32 by contacting the seat element 31 to close the communication path 32.

[0299] The valve element 40 comprises the valve body 41, which has a plate shape, the connecting holes 44, the tapered sections 42, and the guide sections 43. The connecting holes 44 extend through the valve body 41 between one surface and the other surface. The connecting holes 44 are located radially between the communication paths 33 and 32. The tapered sections 42 are located radially outside the valve body 41 and each include the surface facing the pressurization chamber 200. They taper in a direction towards the pressurization chamber 200 along the axis Ax2 of the valve body 41.The guide sections 43 project radially outwards from the valve body 41 to divide the tapered sections 42 in the circumferential direction and are capable of guiding the valve element 40 such that it moves by sliding on the stopper recesses 351 of the stopper 35. The connecting holes 44 are arranged on the virtual circle VC1, which is centered on the axis Ax2 of the valve body 41.

[0300] According to the present embodiment, the seat element 31 includes the communication path 32, which is arranged radially inside the seat element 31, and the communication paths 33, which are arranged radially outside the communication path 32. The valve element 40 is configured to be in contact with and separate from the seat element 31 and has the connecting holes 44, which are positioned radially between the communication path 32 and the communication paths 33.The fuel flows in a route that is arranged radially outside the valve element 40, passing between the valve element 40 and the stopper recess 351, and reaching the communication paths 33 of the seat element 31, a route that passes through the connecting hole 44 of the valve element 40 and the communication path 32 of the seat element 31, and a route that passes through the connecting holes 44 of the valve element 40 and the communication paths 33 of the seat element 31.

[0301] In this case, a flow path area equivalent to that of a configuration with only the flow path between the valve element 40 and the stopper recess 351 can be ensured, even if the stroke of the valve element 40 from the seat element 31 is more significantly reduced than that of a configuration with only a flow path between the valve element 40 and the stopper recess 351. Accordingly, the stroke of the valve element 40 from the seat element 31 can be reduced. As a result, the drive force required to lift the valve element 40 from the seat element 31 can be set to a small force, and the maximum output from the electromagnetic drive unit 500 can be reduced. Therefore, a reduction in the size of the electromagnetic drive unit 500 is achieved.Furthermore, collision noise between the valve element 40 and the needle body 531 can be reduced by decreasing the stroke. Additionally, the response sensitivity of the electromagnetic drive unit 500 can be increased by reducing the stroke. This reduces excessive fuel backflow during quantity control, thereby increasing discharge efficiency during high-speed operation.

[0302] According to the present embodiment, the boundary line B1 between the inner edges of the tapered sections 42 and the outer edges of the valve body 41 is formed along the concentric circle CC1, which corresponds to the virtual circle VC1. This configuration reduces the distance between both ends of each boundary line B1 and the connecting holes 44. In this case, sections near both ends of each boundary line B1 do not impede the flow of fuel over the surface of the valve element 40. Accordingly, a sufficient quantity of fuel can be ensured that is drawn into the pressurization chamber 200. Similarly, a sufficient quantity of fuel can be ensured that is returned from the pressurization chamber 200 to the fuel chamber 260.

[0303] (A2) According to the present embodiment, the number of connecting holes 44 facing the inner edge of one of the tapered sections 42, which are divided by the guide sections 43, is uniformly set to a value of h / g, assuming that the number of connecting holes 44 is h and that the number of guide sections 43 is g. In this case, the connecting holes 44 can be arranged in a balanced manner in accordance with each of the tapered sections 42. Accordingly, a fuel flow passing through the valve element 40 can be stabilized.

[0304] (A3) According to the present embodiment, the boundary line B1 between the inner edge of one tapered section 42, which is sandwiched between the two guide sections 43, and the outer edge of the valve body 41 is located in a region between the two lines of contact LT1 between the outer edges of the end connection holes (441, 443), which are located at both ends of the connection holes 44 facing the inner edge of one of the tapered sections 42, and the outer edges of the connection holes 44 (443, 441), which are symmetrical to the end connection holes (441, 443) with respect to a straight line L11 extending from the center of the valve body 41 to the center of the guide section 43. In this case, the distance between both ends of each of the boundary lines B1 and the connection holes 44 can be reduced while ensuring the length of each of the boundary lines B1.Accordingly, sections near both ends of each of the boundary lines B1 do not present any resistance to fuel flow.

[0305] (A9) In the present embodiment, the high-pressure pump 10 is applied to the fuel supply system 9, which includes the fuel injectors 138 for supplying fuel to the machine 1. The valve element 40 includes the third sealing section 413, which has an annular shape, and seals radially outward between the communication paths 33 and the flow path 45, which is located on the radial outside of the valve element 40 in the fuel supply system 9, in which the maximum injection pressure of the fuel injected by the fuel injectors 138 is 20 MPa or higher. Assuming that the diameter of the third sealing section 413 is D and that the plate thickness of the valve element 40 is t, the plate thickness ratio t / D falls within a range shown in 0.06 < t / D ≤ 0.13.

[0306] Accordingly, the sealing capability is improved in a high fuel pressure environment, while ensuring the strength of the valve element 40, which has sealing sections 410.

[0307] <b-1>Next, the electromagnetic drive unit 500 will be described in detail.

[0308] As in Fig. As shown in Figure 18, the outer peripheral wall of the second columnar section 512 of the cylindrical element 51 has a substantially hexagonal columnar shape. More precisely, the six corners of the outer peripheral wall of the second columnar section 512, located in the circumferential direction on a virtual cylindrical surface centered on the axis of the second columnar section 512, have a curved shape. A gap is formed between a flat section of the outer peripheral wall of the second columnar section 512 and the inner peripheral wall of the coil former 61.

[0309] According to the present embodiment, to screw the cylindrical element 51 into the intake hole section 212 of the upper housing 21 by means of a screw connection, a wall surface of a tool is applied to the outer peripheral wall of the second column-shaped section 512 and rotated to screw the cylindrical element 51 into the intake hole section 212.

[0310] According to the present embodiment, the second column-shaped section 512 of the cylindrical element 51 is located within the inner cylindrical surface 602 of the coil 60, i.e., within the end of the coil body 61 which is arranged facing the pressurization chamber 200, as shown in the Fig. 5 and Fig. Figure 18 shows that in this case, the lengths of the cylindrical element 51 and the needle 53 can be shortened more in the axial direction than in a configuration where a hexagonal column-shaped outer peripheral wall, onto which a wall surface of a tool is applied to screw the cylindrical element 51 into the intake hole section 212, is formed in the outer peripheral wall of the cylindrical element 51 between the pressurization chamber 200 and the coil body 61. In this case, the inertial mass decreases, resulting in improved response sensitivity and a reduction in NV.

[0311] According to the present embodiment, the coil 60 has an inner cylindrical surface 601 and an inner cylindrical surface 602, which have different diameters. The wire 620 is wound radially outward around the inner cylindrical surfaces 601 and 602. As described above, the second columnar section 512 of the cylindrical element 51 is located within the inner cylindrical surface 602 of the coil 60. In this case, the thickness of the second columnar section 512 is allowed to increase in the radial direction, which is why the second columnar section 512 does not become a magnetic choke.

[0312] If the coil 60 includes not the inner cylindrical surface 601, but only the inner cylindrical surface 602, and the wire 620 in the present embodiment is wound the same number of times in the radial direction starting with the inner cylindrical surface 602, the length of the winding section 62 increases in the axial direction. Additionally, the lengths of the solid core 57 and the needle 53 also increase in the axial direction. Accordingly, NV increases, and the resistance of the winding section 62 also increases, which can lead to an increase in the power consumption of the coil 60.

[0313] If the coil 60 has not the inner cylindrical surface 602, but only the inner cylindrical surface 601, and the wire 620 is wound the same number of times in the radial direction in the present embodiment, the same problems can occur as described above. Furthermore, the thickness of the second columnar section 512 of the cylindrical element 51 can decrease in the radial direction, which is why the second columnar section 512 can become a magnetic choke. In this case, the attractive force between the fixed core 57 and the movable core 55 is insufficient, and therefore the required response sensitivity cannot be achieved.

[0314] Fig. Figure 19 schematically shows a portion of the coil 60 in the present embodiment. Accordingly, the relative lengths, sizes, and other characteristics of the respective elements and parts forming the coil 60 differ from the actual dimensions. Additionally, for simplification, the wire 620 is wound less frequently around the outer peripheral wall of the coil former 61 than it actually is.

[0315] As in Fig. As shown in Figure 19, the coil 60 includes a connecting surface 605, which is a virtual surface that connects the inner cylindrical surface 601 and the inner cylindrical surface 602. The connecting surface 605 has a substantially annular shape. The inner cylindrical surface 601, the inner cylindrical surface 602, and the connecting surface 605 are located on the outer peripheral wall of the coil former 61. The connecting surface 605 has a portion that tapers in a direction away from the pressurization chamber 200 towards the axis pf of the coil former 61.

[0316] More precisely, the connecting surface 605 has two connecting sections: one connected to the inner cylindrical surface 601, which has the smallest diameter, and the other connected to the inner cylindrical surface 602, which has the largest diameter. The connecting section connected to the inner cylindrical surface 602 has a tapered shape. The other part of the connecting surface 605, apart from the connecting section connected to the inner cylindrical surface 602, is perpendicular to the axis of the coil former 61.The tapered connecting section of the connecting surface 605, which is connected to the inner cylindrical surface 601, is referred to as a tapered surface section 691, and the left section of the connecting section, which runs perpendicular to the axis of the coil body 61, is referred to as a vertical surface section 692.

[0317] As in Fig. As shown in Figure 19, the angle formed by the inner cylindrical surface 601 and the connecting surface 605, i.e., the small angle θ formed by the inner cylindrical surface 601 and the tapered surface section 691, in a cross-section taken along a virtual plane VP1 on which the axis of the coil former 61 extends, is 120 degrees.

[0318] According to the present embodiment, an end surface 621 of the winding section 62, which is arranged facing the pressurization chamber 200, tapers at a connecting section with the inner cylindrical surface 602. The connecting section and the inner cylindrical surface 602 form an angle of 120 degrees.

[0319] As in Fig. As shown in Figure 19, the wire 620 is wound starting with the inner cylindrical surface 601 to form N layers stacked in a radial direction. The inner cylindrical surface 601 has the smallest diameter of the two inner cylindrical surfaces 601 and 602. According to the present embodiment, N is an even number. Fig. 19 N = 10, that is, the wire is wound 10 times in the radial direction starting with the inner cylindrical surface 601 to form N layers.

[0320] According to the present embodiment, the wire 620 is wound around the outer peripheral wall of the coil former 61 in the axial direction towards the pressurization chamber 200 for the first layer, in the axial direction away from the pressurization chamber 200 for the second layer, and in the axial direction towards the pressurization chamber 200 for the third layer, and is wound repeatedly in this manner to form N layers. As described above, one starting end of the wire 620 and the other end of the wire 620 can be arranged at the end of the coil former 61 that is located away from the pressurization chamber 200 in the axial direction if N is an even number. This configuration facilitates connection of the wire 620 to the terminal 651 (compare the Fig. 22 and Fig. 23).

[0321] As in Fig. As shown in Figure 19, the wire 620 is wound the same number of times in the axial direction for the first layer and the second layer. The first layer is located radially inside the second layer. Fig. Figure 19 shows a simplified state compared to the actual state, representing a case in which the wire 620 for the first layer and the second layer is wound five times in the axial direction. In this case, the wire 620 for the second layer is located between the wire 620 that is wound in the radial direction for the first layer.

[0322] According to the present embodiment, the tapered surface section 691 is in contact with sections of the wire 620 that is wound for the first layer and is located in the axial direction of the coil former 61 closest to the pressurization chamber 200 in the first layer, and that is wound for the second layer and is located in the axial direction closest to the pressurization chamber 200 in the second layer. A connecting section of the vertical surface section 692, which is connected to the tapered surface section 691, is in contact with a section of the wire 620 that is wound for the second layer and is located in the axial direction of the coil former 61 closest to the pressurization chamber 200.Accordingly, the boundary between the tapered surface section 691 and the vertical surface section 692 is located in the second layer of the wire 620, which is wound radially starting from the inner cylindrical surface 601.

[0323] As in Fig. As shown in Figure 19, the wire 620 is wound the same number of times in the axial direction for each layer in a region TB1 between the inner cylindrical surface 601 with the smallest diameter and the inner cylindrical surface 602 with the largest diameter of the two inner cylindrical surfaces 601 and 602. Fig. Figure 19 shows a case in which four layers of wire 620 are formed in the radial direction in the region TB1 between the inner cylindrical surface 601 and the inner cylindrical surface 602. For all layers in region TB1, from the first to the fourth layer, the wire 620 is wound five times in the axial direction. In this case, the wire 620 for the (m + 1)th layer is located between the wire 620 for the mth layer, which are arranged adjacent to each other in the axial direction.

[0324] Next, a comparison between coil 60 in the present embodiment and coil 60 in a comparative example will be described, based on points that are superior to the comparative example in the present embodiment.

[0325] Fig. Figure 20 shows coil 60 according to a first comparative example, while Fig. 21 shows the coil 60 according to a second comparative example.

[0326] As in Fig. As shown in Figure 20, the coil 60 according to the first comparative example differs from the coil 60 according to the present embodiment with respect to the shape of the connection surface 605. According to the coil 60 of the first comparative example, the connection surface 605 has a flat shape, designed such that the entire part is perpendicular to the axis of the coil former 61. A small angle θ formed by the inner cylindrical surface 601 and the connection surface 605 is 90 degrees. Accordingly, a gap Sp1 is formed between the connection surface 605 and the wire 620 for the first layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil former 61.In this case, the wire 620 for the first layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil former 61, can be displaced towards the space Sp1. As a result, the wire 620 for the second layer, which is in contact with the wire 620 for the first layer located closest to the pressurization chamber 200 in the axial direction of the coil former 61, can be displaced in the radial direction of the coil former 61. Accordingly, the state of the wire 620 wound around the coil former 61 can become unstable.

[0327] According to the coil 60 of the present embodiment, an angle formed by the inner cylindrical surface 601 and the connecting surface 605, i.e., a small angle θ formed by the inner cylindrical surface 601 and the tapered surface section 691, in a cross-section of a virtual plane VP1 on which the axis of the coil body 61 extends, is, in contrast, 120 degrees, as in Fig. Figure 19 shows that in this case, the tapered surface section 691 is in contact with the portion of the wire 620 for the first layer that is closest to the pressurization chamber 200 in the axial direction of the coil former 61, and with the portion of the wire 620 for the second layer that is closest to the pressurization chamber 200 in the axial direction of the coil former 61. Accordingly, the coil 60 of the present embodiment does not include the space Sp1 formed in the coil 60 of the first comparative example. The connecting section of the vertical surface section 692, which is connected to the tapered surface section 691, is in contact with the wire 620 for the second layer that is closest to the pressurization chamber 200 in the axial direction of the coil former 61.This configuration of the coil 60 in the present embodiment reduces a positional deviation of the part of the wire 620 for the first layer which is located closest to the pressurization chamber 200 in the axial direction of the coil body 61, and of the wire 620 for the second layer which is in contact with part of the wire 620, thereby stabilizing the condition of the wire 620 which is wound around the coil body 61.

[0328] According to coil 60 of the second comparative example, the wire 620 is wound a different number of times in the axial direction for layers in the area TB1 between the inner cylindrical surface 601 and the inner cylindrical surface 602, as shown in Fig. Figure 21 shows that this aspect differs from the present embodiment. In the coil 60 of the second comparative example, the wire 620 for the first and third layers is wound 5 times in the axial direction, while the wire 620 for the second and fourth layers is wound 4 times in the axial direction. Accordingly, a gap Sp2 is formed between the connection surface 605 and the wire 620 for the second layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil body 61. Furthermore, a gap Sp3 is formed between the connection surface 605 and the wire 620 for the fourth layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil body 61.In this case, the wire 620 for the third layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil former 61, can be displaced towards the space Sp2. Furthermore, the wire 620 for the fifth layer, which faces the space Sp3, can be displaced towards the space Sp3. Consequently, the state of the wire 620 wound around the coil former 61 can become unstable.

[0329] In contrast, in the case of coil 60 in the present embodiment, the wire 620 is wound in the axial direction as many times for each layer in the area TB1 between the inner cylindrical surface 601 and the inner cylindrical surface 602 as in Fig. Figure 19 shows that the coil 60 of the present embodiment does not include the spaces Sp2 and Sp3 that are formed in the coil 60 of the second comparative example. This configuration of the coil 60 in the present embodiment reduces positional deviation of the wire 620 for the third layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil body 61, and of the wire 620 for the fifth layer, thereby stabilizing the condition of the wire 620 wound around the coil body 61.

[0330] As in Fig. As shown in Figure 24, the coil former grooves 611 and 612 are formed in the outer peripheral wall of the coil former 61. An upper part of Fig. Figure 24 shows a developed view of the outer peripheral wall of the coil former 61, while a lower part of Fig. Figure 24 shows a cross-sectional view of the coil body 61.

[0331] The coil former groove 611 extends radially inwards from the outer peripheral wall of the coil former 61 and extends in the circumferential direction of the coil former 61. The coil former is formed at a position on the coil former that corresponds to the inner cylindrical surface 601. The coil former groove 611 is formed in the circumferential direction over essentially the entire area of ​​the coil former 61, except for a portion in the circumferential direction of the coil former 61.

[0332] The coil former groove 612 extends circumferentially around the coil former 61, while radially inwardly recessed from a section corresponding to the inner cylindrical surface 602 in the outer peripheral wall of the coil former 61. The coil former groove 612 is formed circumferentially around the coil former 61 in a range of approximately 90 degrees to 360 degrees. Conversely, the coil former groove 612 is not formed in a region of the outer peripheral wall of the coil former 61, but rather in a region corresponding to the inner cylindrical surface 602 (in a range of 0 degrees to approximately 90 degrees) in the circumferential direction.

[0333] The coil body groove 611 in a part in the outer peripheral wall of the coil body 61 and corresponding to the inner cylindrical surface 601 (in a range from 0 to approximately 90 degrees) in the circumferential direction is arranged inclined to a part of the coil body groove 611 (in a range from 90 to approximately 360 degrees), which is different from the preceding part in the circumferential direction.

[0334] The wire 620 is wound around the coil former 61, with a portion of the wire 620 being inserted into the coil former grooves 611 and 612. This stabilizes the wire 620 within the coil former 61. The position of the wire 620 wound around the coil former 61 can vary during a transition from a section corresponding to the inner cylindrical surface 601 to a section corresponding to the inner cylindrical surface 602 in the outer peripheral wall of the coil former 61. According to the present embodiment, the coil former groove 612 is not formed in a portion of a section in the outer peripheral wall of the coil former 61 corresponding to the inner cylindrical surface 602 in the circumferential direction, as described above.Accordingly, the variations described above regarding the position of the wire 620 can be absorbed by the section in which the coil body groove 612 is not formed in the outer peripheral wall of the coil body 61.

[0335] As described above (B1), the high-pressure pump 10 of the present embodiment comprises the cylinder 23 as the pressurization chamber formation section, the upper housing 21 as the intake passage formation section, the seat element 31, the valve element 40, the cylindrical element 51, the needle 53, the movable core 55 and the spring 54 as the preload element, the fixed core 57 and the coil 60. The cylinder 23 defines the pressurization chamber 200 in which the fuel is pressurized.

[0336] The upper housing 21 defines the intake port 216 through which the fuel flows, which is drawn into the pressurization chamber 200. The seat element 31 is arranged in the intake port 216 and includes the communication path 32 and the communication paths 33, which pass through the seat element 31 between one surface and the other surface. The valve element 40 is arranged between the pressurization chamber 200 and the seat element 31 and is capable of allowing fuel flow in the communication path 32 and the communication paths 33 by separating from the seat element 31 to open the communication path 32 and the communication paths 33, and of restricting fuel flow in the communication path 32 and the communication paths 33 by contacting the seat element 31 to close the communication path 32 and the communication paths 33.

[0337] The cylindrical element 51 is arranged on one side of the seat element 31 opposite the pressurization chamber 200. The needle 53 is axially movable within the cylindrical element 51. The needle 53 has one end capable of contacting the surface of the valve element 40, which is located away from the pressurization chamber 200. The movable core 55 is located at the other end of the needle 53.

[0338] The spring 54 biases the needle 53 towards the pressurizing chamber 200. The fixed core 57 is arranged on one side of the cylindrical element 51 opposite the pressurizing chamber 200. The coil 60 has the winding section 62, which is formed into a cylindrical shape by winding the wire 620 around the coil former 61. The coil 60 generates an attractive force between the fixed core 57 and the movable core 55 to move the movable core 55 and the needle 53 in the closing direction when the winding section is energized.

[0339] The coil 60 comprises the outer peripheral surface 600, which is in contact with the outer peripheral surface of the winding section 62, and the inner cylindrical surfaces 601 and 602, which are also in contact with the inner peripheral surface of the winding section 62. The diameter of the inner cylindrical surface 601 differs from that of the inner cylindrical surface 602. The inner cylindrical surfaces 601 and 602 are arranged to increase in diameter in one direction towards the pressurization chamber 200.

[0340] During a period when at least the coil 60 is not energized, the end surface 551 of the movable core 55, which faces the fixed core 57, is located between the center point Ci1 of the inner cylindrical surface 601 (the inner cylindrical surface with the smallest diameter) and the center point Co1 of the outer cylindrical surface 600, also in the axial direction. This configuration can increase the attractive force acting on the movable core 55 during energization of the coil 60. Consequently, the response sensitivity of the movable core 55 is improved. Moreover, with a high response sensitivity of the movable core 55, the current flowing through the coil 60 can be reduced without reducing the attractive force acting on the movable core 55. Therefore, the power consumption of the electromagnetic drive unit containing the coil 60 can be reduced.

[0341] (B2) According to the present embodiment, the end surface 552 of the movable core 55, which faces the pressurization chamber 200, is located between the fixed core 57 and the end surface 621 of the winding section 62, which also faces the pressurization chamber 200. This configuration can reduce the axial length of the movable core 55, thereby reducing its weight. Consequently, an improvement in the response sensitivity of the movable core 55 and a reduction in NV (Noise Frequency) can be achieved.

[0342] (B3) According to the present embodiment, the coil 60 includes the connecting surface 605, which connects the inner cylindrical surface 601 and the inner cylindrical surface 602. The inner cylindrical surface 601, the inner cylindrical surface 602, and the connecting surface 605 are located on the outer peripheral wall of the coil former 61. The connecting surface 605 is configured such that at least a portion of the connecting surface 605, i.e., the vertical surface section 692, is perpendicular to the axis of the coil former 61. This configuration can reduce positional deviation of the wire 601, which is wound radially outside the inner cylindrical surface 620. Accordingly, this configuration facilitates the manufacture of the coil 60.

[0343] (B4) According to the present embodiment, at least a portion of the connection surface 605, i.e., the tapered surface section 691, tapers in the direction away from the pressurization chamber 200 towards the axis of the coil former 61. Accordingly, the tapered surface section 691 of the connection surface 605 can be brought into contact with the wire 620 for each of the layers that are closest to the pressurization chamber 200 in the axial direction of the coil former 61. This configuration reduces positional deviation of the wire 620.

[0344] (B5) According to the present embodiment, the connecting section of the connecting surface 605, which is connected to the inner cylindrical surface 601 with the smallest diameter, i.e., the tapered surface section 691, has a tapered shape. In a cross-section taken along the virtual plane VP1 on which the axis of the coil former 61 extends, the angle formed by the inner cylindrical surface 601 and the tapered surface section 691 of the connecting surfaces 605 is 120 degrees.In this case, the tapered surface section 691 of the connection surface 605 can be brought into contact with the wire 620 for the first layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil former 61, and with the wire 620 for the second layer, which is located closest to the pressurization chamber 200 in the axial direction of the coil former 61. This configuration reduces positional deviation of the wire 620, particularly at the connection section between the inner cylindrical surface 601 and the connection surface 605. This configuration therefore stabilizes the condition of the wire 620 wound around the coil former 61.

[0345] (B7) According to the present embodiment, the wire 620 is wound radially for N layers, starting at the inner cylindrical surface 601 with the smallest diameter. In this case, N is an even number. The winding start position and the winding end position of the wire 620 are therefore located, for example, at the axial end of the coil former 61, which is located away from the pressurization chamber 200. This configuration can fix the wire 620 along the coil former 61. Accordingly, this configuration reduces excessive stress applied to the wire 620, thereby reducing wire breakage caused by thermal fatigue, even if the coil former 61 is deformed by heat. Moreover, a connection between the terminal 651 and the wire 620 is facilitated by setting N to an even number.

[0346] (B8) According to the present embodiment, the wire 620 is wound the same number of times in the axial direction, starting with the inner cylindrical surface 601 with the smallest diameter for the first layer and the second layer. Accordingly, the wire 620 for the second layer can be arranged adjacent to the wire 620 for the first layer, which is arranged axially to it. Furthermore, the connecting surface 605 and the wire 620 that is closest to the pressurization chamber 200 can be brought into contact with each other in the axial direction of the coil former 61 within the wire 620 of the second layer. This configuration can reduce positional deviation of the wire 620 that is closest to the pressurization chamber 200 in the axial direction of the coil former 61 within the wire 620, particularly in the third layer.This configuration therefore stabilizes the state of the wire 620, which is wound around the coil body 61.

[0347] (B9) In the case of the wire 620, in the present embodiment, the wire 620 is wound the same number of times in the axial direction for each layer in the region TB1 between the inner cylindrical surface 601 with the smallest diameter and the inner cylindrical surface 602 with the largest diameter. Accordingly, the wire 620 in the (N + 1)th layer can be arranged between the wire 620 that is axially adjacent to it in the Nth layer. Moreover, the connecting surface 605 and the wire 620 that is closest to the

[0348] The pressurization chamber 200 is located in the axial direction of the coil former 61, in which the wire 620 of the even-numbered layer is brought into contact with each other. This configuration reduces positional deviation of the wire 620. This configuration therefore stabilizes the state of the wire 620 wound around the coil former 61.

[0349] <c-1>Next, the discharge port 70, the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75, the overflow valve 91, the spring 79 and the spring 99, which form the discharge passage section 700, will be described individually.

[0350] As in the Fig. As shown in Figures 25 to 27, the discharge port 70 has a substantially cylindrical shape. The stepped surface 701, which has a substantially annular shape, is formed within the discharge port 70. The discharge port 70 has a discharge passage 705 within it. The discharge port 70 includes a lateral hole section 702, which passes through the discharge port 70 between an inner peripheral wall and an outer peripheral wall of the discharge port 70. This lateral hole section 702 is formed in the circumferential direction of the discharge port 70. The discharge port 70 includes the polygonal columnar surface 703, which has a substantially hexagonal columnar shape. The polygonal columnar surface 703 is located in the axial direction of the outer peripheral wall of the discharge port 70, substantially at a position radially outside the stepped surface 701.

[0351] As in the Fig. As shown in Figures 28 to 30, the discharge seat element 71 comprises the discharge element body 72, the discharge hole 73, and the discharge valve seat 74. The discharge element body 72 is essentially disc-shaped. An outer diameter of the discharge element body 72 is slightly larger than an inner diameter of one end of the discharge port 70. The discharge element body 72 is positioned within the discharge port 70 such that an outer peripheral wall of the discharge element body 72 is fitted against the inner peripheral wall at one end of the discharge port 70.

[0352] The discharge element body 72 includes a discharge recess 721, an inner projection 722, and an outer projection 723. The discharge recess 721 is cut out in a substantially cylindrical shape extending from the center of one end surface of the discharge element body 72 to the other end surface. The inner projection 722 projects in a substantially annular shape from the other end surface of the discharge element body 72. The outer projection 723 projects in a substantially annular shape from the other end surface of the discharge element body 72 onto the radial outer surface of the inner projection 722.

[0353] The discharge hole 73 has a substantially cylindrical shape and passes through the discharge seat element 71 between the end surface of the discharge element body 72 and the bottom surface of the discharge recess 721. The discharge hole 73 is located on the radial inner side of the inner projection 722. The discharge valve seat 74 has a substantially annular shape and is arranged on the bottom surface of the discharge recess 721 around the discharge hole 73. The discharge recess 721, the inner projection 722, the outer projection 723, the discharge hole 73, and the discharge valve seat 74 are substantially coaxial with the discharge element body 72.

[0354] As in the Fig. As shown in Figures 31 to 33, the intermediate element 81 includes the intermediate element body 82 and the first passages 83. The intermediate element body 82 is essentially disc-shaped. The intermediate element body 82 is in contact with the discharge seat element 71 within one end of the discharge port 70. The outer diameter of the intermediate element body 82 is slightly smaller than the inner diameter of one end of the discharge port 70.

[0355] An intermediate recess 821 is formed in the intermediate element body 82. The intermediate recess 821 is formed in a substantially cylindrical shape, extending from the center point of one end surface of the intermediate element body 82 to the other end surface. The intermediate recess 821 is substantially coaxial with the intermediate element body 82.

[0356] The first openings 83 each have a substantially cylindrical shape and pass through the intermediate element body 82 between one end surface and the other end surface of the intermediate element body 82. The first openings 83 are located on the radial outside of the intermediate recess 821. The five first openings 83 are formed at equal intervals in the circumferential direction of the intermediate element body 82.

[0357] According to the present embodiment, an annular recess 800 is formed in the intermediate element 81. The annular recess 800 has a substantially ring-shaped form, extending from the other end surface towards one end surface of the intermediate element body 82. The annular recess 800 is substantially coaxial with the intermediate element body 82. The annular recess 800 is connected to the ends of all of the first passages 83.

[0358] As in the Fig. As shown in Figures 34 to 36, the overflow seat element 85 comprises the overflow element body 86, the overflow hole 87, the overflow valve seat 88, the second passages 89, the outer peripheral overflow recess 851, the lateral overflow hole 852, and the lateral hole 853. The overflow element body 86 has a cylindrical overflow element section 861 and an overflow element bottom section 862. The cylindrical overflow element section 861 has a substantially cylindrical shape. The overflow element bottom section 862 is integrally formed with the cylindrical overflow element section 861 in such a shape to close one end of the cylindrical overflow element section 861.

[0359] The inner peripheral wall of the cylindrical section 861 of the overflow element is configured such that the inner diameter of a section 806, located between the pressurization chamber 200 and the sliding section 805, which slides on the overflow valve sliding section 93, is larger than the inner diameter of the sliding section 805. The inner peripheral wall of the cylindrical section 861 of the overflow element is configured such that the inner diameter of a section 807, located between the pressurization chamber 200 and the sliding section 806, is larger than the inner diameter of the sliding section 806 (compare Fig. 34).

[0360] The overflow element body 86 is provided within the discharge port 70 and is located on one side of the intermediate element 81 opposite the discharge seat element 71. An outer diameter of the cylindrical section 861 of the overflow element is essentially equivalent to an inner diameter of a section located between the discharge seat element 71 and the step surface 701 of the discharge port 70.The overflow element body 86 is provided within the discharge port 70 such that the end surface of the cylindrical section 861 of the overflow element, which is arranged facing away from the overflow element bottom section 862, is in contact with an outer edge of the end surface of the intermediate element body 82, and that an outer edge of the end surface of the cylindrical section 861 of the overflow element, which is arranged facing away from the overflow element bottom section 862, is in contact with the step surface 701 of the discharge port 70.

[0361] The overflow hole 87 has a substantially cylindrical shape and passes through the base section 862 of the overflow element between one surface and the other surface at the center of the base section 862 of the overflow element. The overflow valve seat 88 is formed in an annular shape on one of the surfaces of the base section 862 of the overflow element surrounding the overflow hole 87. The overflow valve seat 88 tapers in one direction from side to side in the axial direction of the cylindrical section 861 of the overflow element towards the axis of the cylindrical section 861 of the overflow element. The overflow hole 87 and the overflow valve seat 88 are substantially coaxial with the overflow element body 86.

[0362] Each of the second passages 89 has a substantially cylindrical shape and passes through the cylindrical section 861 of the overflow element between one end surface and the other end surface at the center of the cylindrical section 861 of the overflow element. The four second passages 89 are formed at equal intervals in the circumferential direction of the cylindrical section 861 of the overflow element.

[0363] The outer peripheral overflow recess 851 has a substantially cylindrical shape, which extends radially inwards from the outer peripheral wall of the cylindrical section 861 of the overflow element. The lateral overflow hole 852 has a substantially cylindrical shape and passes through the cylindrical section 861 of the overflow element between the outer peripheral overflow recess 851 and an inner peripheral wall of the cylindrical section 861 of the overflow element. The two lateral overflow holes 852 are formed at 90-degree intervals in a circumferential direction of the cylindrical section 861 of the overflow element (compare Fig. 35) By positioning the two lateral overflow holes 852 at unequal intervals in the circumferential direction, a stable flow can be achieved, whereby the overflow valve 91 is offset to one side during operation of the open valve. If the two lateral overflow holes 852 are arranged at equal intervals in the circumferential direction, the direction of the offset is not determined by variations with respect to a vacuum equilibrium. In this case, the behavior of the overflow valve 91 may become unstable.

[0364] The lateral hole 853 has a substantially cylindrical shape and passes through the cylindrical section 861 of the overflow element between the outer peripheral overflow recess 851 and the inner peripheral wall of the cylindrical section 861 of the overflow element. The lateral hole 853 is located on the side of the lateral overflow hole opposite the overflow element bottom section 862. The lateral hole 853 is formed in the circumferential direction of the cylindrical section 861 of the overflow element. The inner diameter of the horizontal hole 853 is equal to the inner diameter of the lateral overflow hole 852.

[0365] The annular recess 800 connects the passages 83 of the intermediate element 81 and the second passages 89 of the overflow seat element 85 in a state in which the overflow element body 86 is located on the side of the intermediate element 81 opposite the discharge seat element 71 within the discharge port 70. According to the present embodiment, the axial length of the cylindrical section 861 of the overflow element, in which the second passages 89 are formed, is greater than the axial length of the intermediate element body 82, in which the first passages 83 are formed.

[0366] As in the Fig. As shown in Figures 37 to 39, the discharge valve 75 comprises the discharge valve contact section 76 and the discharge valve sliding section 77. The discharge valve contact section 76 is essentially disc-shaped. An outer diameter of the discharge valve contact section 76 is smaller than an inner diameter of the discharge recess 721 of the discharge seat element 71 and larger than an inner diameter of the intermediate recess 821 of the intermediate element 81. The discharge valve contact section 76 is positioned within the discharge recess 721 such that the outer edge of a surface of the discharge valve contact section 76 can contact the discharge valve seat 74 or be arranged separately from the discharge valve seat 74.

[0367] The discharge valve sliding section 77 is integrally formed with the discharge valve contact section 76 in such a way that it projects from the other surface of the discharge valve contact section 76 in a substantially cylindrical shape. The discharge valve sliding section 77 is substantially coaxial with the discharge valve contact section 76. The outer diameter of the discharge valve sliding section 77 is slightly smaller than the inner diameter of the intermediate recess 821. The discharge valve 75 is designed such that the outer peripheral wall of the discharge valve sliding section 77 can move back and forth in the axial direction while sliding along the inner peripheral wall of the intermediate recess 821.

[0368] Holes 771 are formed in the discharge valve sliding section 77. The holes 771 each have a substantially cylindrical shape and extend through the discharge valve sliding section 77 between the inner peripheral wall and the outer peripheral wall of the discharge valve sliding section 77. The four holes 771 are formed at equal intervals in the circumferential direction of the discharge valve sliding section 77. The holes 771 are fluidically connected to a space inside the discharge valve sliding section 77 and to a space outside the discharge valve sliding section 77.

[0369] According to the present embodiment, the inner peripheral wall of the discharge valve sliding section 77 tapers such that the inner diameter increases in a direction away from the discharge valve contact section 76 and from the discharge valve contact section 76 (compare Fig. 37). This configuration reduces contact between the outer peripheral section of the spring 79 and the inner peripheral wall of the discharge valve sliding section 77. Additionally, this configuration has no step on the inner peripheral wall of the discharge valve sliding section 77, thus simplifying deburring. According to the present embodiment, the end surface of the discharge valve contact section 76 and the holes 771 are arranged separately from each other for machinability purposes.

[0370] As in the Fig. As shown in Figures 40 to 42, the overflow valve 91 comprises the overflow valve contact section 92, the overflow valve sliding section 93, and the projecting section 94 of the overflow valve. The overflow valve contact section 92 has a substantially cylindrical shape. The overflow valve contact section 92 has a tapered shape such that an outer peripheral wall at one end of the overflow valve contact section 92 tapers from the other side toward the axis to one side. The overflow valve contact section 92 is positioned within the cylindrical section 861 of the overflow element such that one end of the overflow valve contact section 92 can contact the overflow valve seat 88 or be separated from the overflow valve seat 88.

[0371] The overflow valve sliding section 93 has a substantially cylindrical shape. The overflow valve sliding section 93 is integrally formed with the overflow valve contact section 92 such that one end of the overflow valve sliding section 93 is connected to the other end of the overflow valve contact section 92. The overflow valve sliding section 93 is substantially coaxial with the overflow valve contact section 92. An outer diameter of the overflow valve sliding section 93 is slightly smaller than an inner diameter of the cylindrical section 861 of the overflow element. The outer peripheral wall of the overflow valve sliding section 93 can slide on the inner peripheral wall of the cylindrical section 861 of the overflow element in a state in which the overflow valve sliding section 93 is located within the cylindrical section 861 of the overflow element.

[0372] The overflow valve sliding section 93 has a tapered shape such that an outer peripheral wall of the end of the overflow valve sliding section 93 facing the overflow valve contact section 92 tapers in a direction away from the overflow valve contact section 92 towards the axis. When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the lateral overflow hole 852 of the overflow seat element 85 is closed by the outer peripheral wall of the overflow valve sliding section 93 (compare Fig. 6).

[0373] The projecting section 94 of the overflow valve has a substantially cylindrical shape. The projecting section 94 of the overflow valve is integrally formed with the overflow valve sliding section 93 such that one end of the projecting section 94 of the overflow valve is connected to the center point of the end surface of the overflow valve sliding section 93 opposite the overflow valve contact section 92. The projecting section 94 of the overflow valve is substantially coaxial with the sliding section 93 of the overflow valve. The outer diameter of the projecting section 94 of the overflow valve is smaller than the outer diameter of the overflow valve sliding section 93.When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the end surface of the protruding section 94 of the overflow valve is located opposite the overflow valve sliding section 93 between the overflow element bottom section 862 and the end surface of the cylindrical section 861 of the overflow element, which is arranged facing away from the overflow element bottom section 862 (compare . Fig. 6).

[0374] As in Fig. As shown in Figure 6, the stop element 95 is essentially disc-shaped. An outer diameter of the stop element 95 is slightly larger than an inner diameter of section 807 of the inner peripheral wall of the cylindrical section 861 of the transfer element. The stop element 95 is press-fitted within the cylindrical section 861 of the transfer element such that the outer peripheral wall of the stop element 95 is fitted against section 807 on the inner peripheral wall of the cylindrical section 861 of the transfer element. In other words, the stop element 95 is essentially coaxial with the cylindrical section 861 of the transfer element. The stop element 95 is positioned in the axial direction of the cylindrical section 861 of the transfer element near the end of the cylindrical section 861 of the transfer element on the side opposite the transfer element bottom section 862.

[0375] The inner diameter of the stop element 95 is larger than the outer diameter of the projecting section 94 of the overflow valve. When the overflow valve contact section 92 is in contact with the overflow valve seat 88, the end surface of the projecting section 94 of the overflow valve, which faces away from the overflow valve sliding section 93, is located within the stop element 95. The gap Sq1, which has a substantially cylindrical shape, is formed between the inner peripheral wall of the stop element 95 and the outer peripheral wall of the projecting section 94 of the overflow valve. Accordingly, the inner peripheral wall of the stop element 95 and the outer peripheral wall of the projecting section 94 of the overflow valve do not slide against each other.

[0376] As in the Fig. 43 and Fig. As shown in Figure 44, the spring 79 is formed into a coil shape by winding the metal wire component 790. The spring 79 includes a spring end surface 791 and a spring end surface 792. The spring end surface 791, which has a flat shape, is formed at one axial end of the spring 79. The spring end surface 792, which also has a flat shape, is formed at the other axial end of the spring 79.

[0377] The spring 79 is positioned within the discharge valve sliding section 77 such that the spring end surface 791 comes into contact with the bottom surface of the intermediate recess 821 of the intermediate element 81, and that the spring end surface 792 comes into contact with the side end surface of the discharge valve sliding section 77 of the discharge valve contact section 76 of the discharge valve 75. In this state, the spring 79 can bias the discharge valve 75 to the side opposite the intermediate element 81. The wire diameter of the wire element 790 is smaller than the inner diameter of the lateral hole 853 of the overflow seat element 85.

[0378] As in the Fig. 45 and Fig. As shown in Figure 46, the spring 99 is formed into a coil shape by winding the metal wire element 990. The wire diameter of the wire element 990 is larger than the wire diameter of the wire element 790. The spring 99 comprises a spring end surface 991 and a spring end surface 992. The spring end surface 991, which has a flat shape, is formed at one axial end of the spring 99. The spring end surface 992, which also has a flat shape, is formed at the other axial end of the spring 99.

[0379] The spring 99 is positioned within the cylindrical section 861 of the overflow element such that the spring end surface 991 comes into contact with the end surface of the overflow valve sliding section 93, which faces the projecting section 94 of the overflow valve, and that the spring end surface 992 comes into contact with the end surface of the stop element 95, which faces the overflow element bottom section 862. In this state, the spring 99 can bias the overflow valve 91 towards the overflow element bottom section 862. The bias force of the spring 99 can be controlled by controlling the axial position of the stop element 95 with respect to the section 807 of the inner peripheral wall of the cylindrical section 861 of the overflow element.

[0380] According to the present embodiment, the intermediate element 81 includes five, i.e., an odd number, of the passages 83, which are formed at equal intervals in the circumferential direction, as described above. The overflow seat element 85 includes four, i.e., an even number, of the second passages 89, which are formed at equal intervals in the circumferential direction. The number of first passages 83 and the number of second passages 89 are relatively prime. This configuration can reduce variations in the overlap area of ​​the first passages 83 and the second passages 89, as viewed in the axial direction of the intermediate element 81, during any relative rotations of the intermediate element 81 and the overflow seat element 85 about the axis.This configuration therefore reduces variations in fuel flow in accordance with a relative positional relationship between the intermediate element 81 and the transfer seat element 85 in the direction of rotation. Accordingly, a reduction in variations in the discharge quantity for each product can be achieved.

[0381] According to the present embodiment, the discharge valve 75 comprises the discharge valve contact section 76, which is capable of contacting the discharge valve seat 74, and the discharge valve sliding section 77, which is formed between the intermediate element 81 and the discharge valve contact section 76 and is slidable on the intermediate element 81. The outer diameter of the discharge valve sliding section 77 is smaller than the outer diameter of the discharge valve contact section 76.

[0382] In the open state of the discharge valve 75, fuel flows in the discharge recess 721 towards the discharge hole 73 when the volume of the pressurization chamber 200 increases due to a displacement of the plunger 11 away from the pressurization chamber 200. In this state, the fuel flow collides with the outer edge of the side surface of the discharge valve sliding section 77 of the discharge valve contact section 76. Accordingly, the discharge valve 75 can be closed rapidly.

[0383] According to the present embodiment, the discharge seat element 71 comprises the inner projection 722 and the outer projection 723. The inner projection 722 extends in an annular shape from the surface of the discharge element body 72, which faces the pressurization chamber 200, towards the pressurization chamber 200 and contacts the bottom surface of the discharge hole section 214 of the upper housing 21, which forms the discharge passage formation section. The discharge element 71 is located on the radial outside of the discharge hole 73. The outer projection 723 extends in an annular shape from the surface of the discharge element body 72, which faces the pressurization chamber 200, towards the pressurization chamber 200 and contacts the bottom surface of the discharge hole section 214 of the upper housing 21. The outer projection 723 is located on the radial outside of the inner projection 722.

[0384] If the inner projection 722 is not formed, but only the outer projection 723 is formed, a gap is created between the end surface of the discharge element body 72, which faces the inner edge of the pressurization chamber 200, and the bottom surface of the discharge hole section 214. In this case, the inner edge of the discharge element body 72 is inclined such that it deforms towards the pressurization chamber 200 at the time of contact between the discharge valve 75 and the discharge valve seat 74. As a result, slippage can occur between the discharge seat element 71 and the discharge valve 75, causing abrasion.

[0385] According to the present embodiment, the inner projection 722 is formed radially within the outer projection 723. In this case, an inclination of the inner edge of the discharge element body 72 towards the pressurization chamber 200 at the time of contact between the discharge valve 75 and the discharge valve seat 74 can be reduced. Accordingly, abrasion between the discharge seat element 71 and the discharge valve 75 can be reduced.

[0386] Deformation of the discharge seat element 71 can be reduced by providing the inner projection 722 in a position that axially overlaps the sealing section formed by the discharge valve 75 (compare Fig. 6).

[0387] The end of the discharge element body 72, which faces the pressurization chamber 200, is not brought into contact with the bottom surface of the discharge hole section 214; instead, the inner projection 722 and the outer projection 723 are in contact with the bottom surface of the discharge hole section 214. This configuration ensures sufficient surface pressure of the discharge seat element 71 on the bottom surface of the discharge hole section 214.

[0388] According to the present embodiment, the discharge seat element 71, the intermediate element 81, and the overflow seat element 85 have the same degree of hardness. The hardness of the intermediate element 81 can be lower than that of the discharge seat element 71 and the overflow seat element 85. In this case, the sealing capacity is improved.

[0389] According to the present embodiment, the overflow valve 91 comprises the overflow valve contact section 92, which is capable of contacting the overflow valve seat 88, and the overflow valve sliding section 93, which is formed on the side of the overflow valve contact section 92 facing the intermediate element 81 and can slide on the overflow element body 86. The center of gravity of the overflow valve 91 is set at the overflow valve sliding section 93. In this case, the overflow valve 91 is not simply inclined during a simple grinding operation of the sliding section of the overflow valve sliding section 93, which slides on the overflow element body 86. Accordingly, grinding is performed in a simple manner.Additionally, a force is applied to a section containing the center of gravity when the center of gravity is located on the overflow valve sliding section 93, which is a section that slides on the overflow element body 86. Accordingly, the movement of the overflow valve 91 is stabilized.

[0390] According to the present embodiment, the overflow element body 86 has a cylindrical shape. The overflow seat element 85 includes the lateral hole 853, which passes through the overflow element body 86 between the inner peripheral wall and the outer peripheral wall of the overflow element body 86. The present embodiment further includes the spring 99, which forms an overflow valve preloading element. The spring 99 is formed in a coil shape by winding the wire element 990, is provided within the overflow element body 86, and preloads the overflow valve 91 towards the overflow valve seat 88. The wire diameter of the wire element 990 is smaller than the inner diameter of the lateral hole 853. Accordingly, the wire element 990 of the spring 99 prevents the lateral hole 853 from being closed.

[0391] According to the present embodiment, the overflow element body 86 has a cylindrical shape. The overflow valve 91 comprises the overflow valve contact section 92, which is capable of contacting the overflow valve seat 88; the overflow valve sliding section 93, which is formed on the side of the overflow valve contact section 92 facing the intermediate element 81 and which can slide on the inner peripheral wall of the overflow element body 86; and the projecting section 94 of the overflow valve, which projects from the overflow valve sliding section 93 toward the intermediate element 81. According to the present embodiment, the spring 99 and the stop element 95 are also provided, forming an overflow valve preloading element. The spring 99 is located within the overflow element body 86 and preloads the overflow valve 91 toward the overflow valve seat 88.The stop element 95 has a cylindrical shape and is positioned within the overflow element body 86 such that part of the projecting section 94 of the overflow valve is located within it to stop one end of the spring 99. The intermediate space Sq1, which has a cylindrical shape, is formed between the outer peripheral wall of the projecting section 94 of the overflow valve and the inner peripheral wall of the stop element 95. This allows the fuel to flow between the stop element 95 and the overflow valve sliding section 93, via the intermediate space Sq1, towards the pressurization chamber 200 when the overflow valve 91 opens and moves towards the pressurization chamber 200.In this case, a damping effect is applied to the fuel in the space between the stop element 95 and the overflow valve sliding section 93, reducing resistance to movement of the overflow valve 91 in the opening direction.

[0392] According to the present embodiment, the intermediate element 81, when in contact with the overflow valve 91, is able to regulate the movement of the overflow valve 91 towards the pressurization chamber 200. According to the present embodiment, when fuel is discharged from the pressurization chamber 200, the pressure in the side chamber of the pressurization chamber 200 of the discharge passage 705 is higher with respect to the intermediate element 81 than the pressure in the side chamber of the overflow seat element 85 of the discharge passage 705 with respect to the intermediate element 81. In this case, pressure is applied to the intermediate element 81 in the direction from the pressurization chamber 200 towards the overflow seat element 85. As a result, the stress on the contact surface of the intermediate element 81 that contacts the overflow valve 91 increases.Accordingly, the movement of the intermediate element 81 towards the pressurization chamber 200 can be reduced, even if the overflow valve 91 comes into contact with the intermediate element 81.

[0393] As described above (C1), the high pressure pump 10 of the present embodiment includes the cylinder 23, which forms the pressurization chamber formation section, and the upper housing 21, the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75 and the overflow valve 91, which forms the discharge passage formation section.

[0394] The cylinder 23 forms the pressurization chamber 200, in which fuel is pressurized. The upper housing 21 defines the discharge passage 217, through which the fuel flows that is discharged from the pressurization chamber 200. The discharge seat element 71 comprises the discharge element body 72, which is arranged in the discharge passage 217; the discharge hole 73, which passes through the discharge seat element 71 between the surface of the discharge element body 72 facing the pressurization chamber 200 and the surface of the discharge element body 72 facing away from the pressurization chamber 200; and the discharge valve seat 74, which is arranged around the discharge hole 73 on the surface of the discharge element body 72 facing away from the pressurization chamber 200.

[0395] The intermediate element 81 includes the intermediate element body 82, which is arranged on the side of the discharge seat element 71 opposite the pressurization chamber 200, and the first passages 83, which pass through the intermediate element body 82 between the surface of the intermediate element body which is arranged facing the pressurization chamber 200 and the surface of the intermediate element body 82 which is arranged away from the pressurization chamber 200.The overflow seat element 85 comprises the overflow element body 86, which is arranged on the side of the intermediate element 81 opposite the pressurization chamber 200; the overflow hole 87, which passes through the overflow element body 86 between the surface of the overflow element body 86 facing the pressurization chamber 200 and the surface of the overflow element body 86 facing away from the pressurization chamber 200; the overflow valve seat 88, which is formed around the overflow hole 87 on the surface of the overflow element body 86 facing the pressurization chamber 200; and the second passage 89, which passes through the overflow element body 86 between the surface of the overflow element body 86 facing the pressurization chamber 200 and the surface of the overflow element body 86 facing away from the pressurization chamber 200. It is arranged facing away from the center at 200, and passes through.

[0396] The discharge valve 75 is arranged between the intermediate element 81 and the discharge seat element 71 and is capable of allowing fuel flow into the discharge port 73 by being separated from the discharge valve seat 74 to open the discharge port 73, and of restricting the fuel flow into the discharge port 73 by contacting the discharge valve seat 74 to close the discharge port 73. The overflow valve 91 is arranged between the intermediate element 81 and the overflow seat element 85 and is capable of allowing fuel flow into the overflow port 87 by being separated from the overflow valve seat 88 to open the overflow port 87, and of restricting the fuel flow into the overflow port 87 by contacting the overflow valve seat 88.

[0397] At least one of the intermediate elements 81 or the transfer seat element 85 includes the annular recess 800, which has an annular shape on the opposing surfaces of the intermediate element body 82 and the transfer element body 86, and fluidly connects the first passages 83 and the second passages 89. In this case, the first passages 83 and the second passages 89 are connected to each other via the annular recess 800 during any rotation of the intermediate element 81 and the transfer seat element 85 about the axis. Accordingly, regardless of the relative positions of the intermediate element 81 and the transfer seat element 85, a flow path for fuel can be ensured, which is conveyed from the pressurization chamber 200 to the machine 1.

[0398] According to the present embodiment, the discharge valve 75 is arranged near the pressurization chamber 200, while the overflow valve 91 is arranged on the side of the discharge valve 75 opposite the pressurization chamber 200. This configuration can reduce a dead volume that is connected to the pressurization chamber 200 and becomes a high-pressure space during pressurization. Accordingly, discharge from the high-pressure pump 10 can be achieved.

[0399] According to the present embodiment, the discharge valve 75 and the overflow valve 91 can be arranged coaxially and integrated within a predetermined area. Accordingly, this configuration can reduce the size of the discharge passage section 700, which is a part that includes the discharge valve 75 and the overflow valve 91, and can therefore reduce the size of the high-pressure pump 10.

[0400] (C2) According to the present embodiment, the first passages 83 are formed circumferentially in the intermediate element body 82. The second passages 89 are formed circumferentially in the overflow element body 86. Accordingly, a sufficient flow rate of fuel can be ensured, which is discharged from the pressurization chamber 200 to the machine 1.

[0401] When the first passages 83 and the second passages 89 are formed, the overlap area of ​​the first passages 83 and the second passages 89 can become extremely small, depending on the relative positions of the intermediate element 81 and the overflow seat element 85, as viewed in the axial direction of the intermediate element 81. According to the present embodiment, however, the annular recess 800, which connects the first passages 83 and the second passages 89, is formed in the intermediate element 81. Accordingly, regardless of the relative positions of the intermediate element 81 and the overflow seat element 85, a sufficient flow rate of fuel can be ensured, which is discharged from the pressurization chamber 200 to the machine 1.

[0402] (C3) According to the present embodiment, the number of first passages 83 differs from the number of second passages 89. Accordingly, the angle of deviation between the center point of each of the first passages 83 and the center point of each of the second passages 89 can be reduced.

[0403] (C4) According to the present embodiment, the number of first passages 83 is greater than the number of second passages 89. The annular recess 800 is formed in the intermediate element body 82. More precisely, the annular recess 800 is formed in the intermediate element 81, which is the element that has the greater number of flow paths in the intermediate element 81 and the overflow seat element 85.

[0404] Generally, the tip of a toothed tool that forms a recess by cutting a part has a rounded corner. Similarly, a corner of the recess in the part has a rounded shape when a recess is formed by cutting or machining it with a toothed tool. If the first passages 83 intersect a rounded corner of the annular recess 800, sharp corners are formed at the intersection points. In this case, a load is concentrated on these corners. Therefore, to ensure strength, it is necessary to reduce the flow path area of ​​the first passages 83 to prevent an intersection line between the first passages 83 and the rounded corners of the annular recess 800.According to the present embodiment, the number of first passages 83 is greater than the number of second passages 89 in order to ensure a sufficient flow rate of fuel flowing in the first passages 83, even if the flow path area of ​​the first passages 83 is reduced.

[0405] (C5) According to the present embodiment, the number of first passages 83 and the number of second passages 89 are relatively prime. This configuration can reduce variations in the overlap area of ​​the first passages 83 and the second passages 89, as viewed in the axial direction of the intermediate element 81, during any relative rotations of the intermediate element 81 and the transfer seat element 85 about the axis. This configuration therefore reduces variations in fuel flow in accordance with a relative positional relationship between the intermediate element 81 and the transfer seat element 85 in the direction of rotation. Accordingly, a reduction in variations in the discharge quantity for each product can be achieved.

[0406] (C6) According to the present embodiment, the number of first passages 83 is greater than the number of second passages 89. The length of each of the first passages 83 is less than the length of each of the second passages 89. The number of first passages 83 is greater than the number of second passages 89. Accordingly, a sufficient flow rate can be ensured even if the flow path area through one of the first passages 83 is reduced. For example, if the flow path area of ​​each of the first passages 83 is reduced, the diameter of the holes formed by the first passages 83 decreases. In this case, processing can become difficult. However, according to the present embodiment, the length of each of the first passages 83 is less than the length of each of the second passages 89.Accordingly, processing of the first passage 83 can be achieved in a simple manner, even if the flow path area of ​​each of the first passages 83 is reduced.

[0407] (C7) According to the present embodiment, the discharge port 70 is further arranged. The discharge port 70 has a cylindrical shape and encloses the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75, and the overflow valve 91. Additionally, the outer peripheral wall of the discharge port 70 is coupled to the upper housing 21. In this case, the discharge port 70, the discharge seat element 71, the intermediate element 81, the overflow seat element 85, the discharge valve 75, and the overflow valve 91 can be pre-assembled into a single body to form a subassembly. Accordingly, the entire high-pressure pump 10 can be easily assembled, thus simplifying its manufacture. Second embodiment

[0408] <a-2>The Fig. 47 and Fig. Figure 48 shows a part of a high-pressure pump according to a second embodiment. The second embodiment differs from the first embodiment with respect to the configuration of the valve element 40.

[0409] According to the present embodiment, the boundary line B1 between the inner edge of the tapered section 42 radially outside the first region T1 of the valve body 41 and the outer edge of the valve body 41 is formed in a region between the straight line LC11, which extends from the center of the valve body 41 and passes through the center of the end connection hole 441 of the first region T1, and the straight line LC11, which extends from the center of the valve body 41 and passes through the center of the connection hole 443 in the first region T1.

[0410] The boundary line B1 between the inner edge of the tapered section 42 radially outside the second region T2 of the valve body 41 and the outer edge of the valve body 41 and the boundary line B1 between the inner edge of the tapered section 42 radially outside the third region T3 of the valve body 41 and the outer edge of the valve body 41 are formed similarly to the preceding boundary line B1.

[0411] According to (A4), in the present embodiment, the boundary line B1 is formed, in other words, between the inner edge of the tapered section 42, which is sandwiched between the two guide sections 43, and the outer edge of the valve body 41 in a region between the two straight lines LC11 extending from the center of the valve body 41 and passing through the centers of the end connection holes (441, 443), which are connection holes 44 at both ends of the connection holes 44 facing the inner edge of the tapered section 42. In this case, the distance between both ends of each of the boundary lines B1 and the connection holes 44 can be reduced while ensuring the length of each of the boundary lines B1. Accordingly, sections near both ends of each of the boundary lines B1 do not impede fuel flow. Third embodiment

[0412] <a-3>The Fig. 49 and Fig. Figure 50 shows a part of a high-pressure pump according to a third embodiment. The third embodiment differs from the second embodiment with respect to the configuration of the valve element 40.

[0413] According to the present embodiment, the guide section 43, through which the straight line L11 passes between the first region T1 and the second region T2, includes the sliding section 430, which is a section that slides on the inner peripheral wall of the stopper recess 351 of the stopper 35, which forms the intake passage formation section.The sliding section 430 is formed between a contact line LT21, which is a contact line on the side of the connecting hole 441 in the second region T2, of two contact lines extending from the center of the valve body 41 and passing through the outer edge of the connecting hole 443 in the first region T1, and a contact line LT21, which is a contact line on the side of the connecting hole 443 in the first region T1, of the two contact lines extending from the center of the valve body 41 and passing through the outer edge of the connecting hole 441 in the second region T2.

[0414] The guide section 43, through which the straight line L11 passes between the second region T2 and the third region T3, and the guide section 43, through which the straight line L11 passes between the third region T3 and the first region T1, are designed similarly to the preceding guide section 43.

[0415] (A5) According to the present embodiment, the guide section 43 has a sliding section 430, which is a section that slides on the stop recess 351 of the stopper 35. The sliding section 43 is formed in the area between the two tangent lines LT21 extending from the center of the valve body 41 and passing through the two edges facing the two adjacent connecting holes 44. In this case, the size of the sliding section 430 of the guide section 43 can be determined according to the distance between the adjacent connecting holes 44. Accordingly, the sliding section 430 does not interfere with fuel flow. Fourth embodiment

[0416] <a-4>The Fig. 51 and Fig. Figure 52 shows a part of a high-pressure pump according to a fourth embodiment. The fourth embodiment differs from the first embodiment with respect to the configuration of the valve element 40.

[0417] According to the present embodiment, the four guide sections 43 are formed at equal intervals in the circumferential direction of the valve body 41 to divide the four tapered sections 42 in the circumferential direction. The eight connecting holes 44 are formed at equal intervals in the circumferential direction of the valve body 41. The connecting holes 44 are arranged on a virtual circle VC1, which is centered on the axis Ax2 of the valve body 41 (compare the Fig. 51 and Fig. 52). As in Fig. As shown in Figure 51, the boundary line B1 between the inner edges of the four tapered sections 42 and the outer edge of the valve body 41 is formed along the concentric circle CC1, which corresponds to the virtual circle VC1.

[0418] As in Fig. As shown in Figure 51, the two connecting holes 44 are included in the first region T1, the second region T2, the third region T3 and a fourth region T4 in the valve body 41 and are defined by the four straight lines L11, each of which is included in the valve body 41, extending from the center of the valve body 41 and passing through the center of the guide section 43.

[0419] Assuming that the number h of connecting holes 44 is 8, and that the number g of guide sections 43 is 4, the number of connecting holes 44 facing an inner edge of one of the plurality of tapered sections 42 separated by the guide sections 43 is calculated as h / g = 8 / 4 = 2.

[0420] Assuming that the two connecting holes 44, which are formed in the first region T1, the second region T2, the third region T3 and the fourth region T4, are the connecting hole 441 and the connecting hole 442, which are arranged in this order in the circumferential direction of the virtual circle VC1, the boundary line B1 between the inner edge of the tapered section 42 on the radial outside of the first region T1 of the valve body 41 and the outer edge of the valve body 41 is located in a region between a line of contact LT31, which is formed at one position, where two lines of contact pass through the outer edge of the connecting hole 441 in the first region T1 and the outer edge of the connecting hole 442, which are included in the second region T2, are formed at one position,which is line-symmetrical with respect to the line L11 between the first region T1 and the second region T2 to the connecting hole 441 in the first region T1, is a line of tangency on the side opposite the third region T3 and the fourth region T4, and a line of tangency LT31, which is formed at two lines of tangency that pass through the outer edge of the connecting hole 442 in the first region T1 and the outer edge of the connecting hole 441, which are included in the fourth region T4 and are formed at a position that is line-symmetrical with respect to a line L11 formed between the first region T1 and the fourth region T4 to the connecting hole 442 in the first region T1, is a line of tangency on the side opposite the second region T2 and the third region T3.

[0421] The boundary line B1 between the inner edge of the tapered section 42 radially outside the second region T2 of the valve body 41 and the outer edge of the valve body 41, the boundary line B1 between the inner edge of the tapered section 42 radially outside the third region T3 of the valve body 41 and the outer edge of the valve body 41, and the boundary line B1 between the inner edge of the tapered section 42 radially outside the fourth region T4 of the valve body 41 and the outer edge of the valve body 41 are formed similarly to the preceding boundary line B1.

[0422] (A3) According to the present embodiment, the boundary line B1 between the inner edge of the tapered section 42, which is sandwiched between the two guide sections 43, and the outer edge of the valve body 41 is formed in a region between the two contact lines LT31, which pass through the outer edges of the end connection holes 44 (441, 442), which are the connection holes at both ends of the connection holes 44 facing the inner edge of a tapered section 42, and the outer edges of the connection holes 44 (442, 441), which are formed at positions that are line-symmetrical with respect to a straight line L11 extending from the center of the valve body 41 and passing through the center of the guide section 43,In this case, the distance between both ends of each of the boundary lines B1 and the connecting holes 44 can be reduced, while ensuring the length of each of the boundary lines B1. Accordingly, sections near both ends of each of the boundary lines B1 do not present any resistance to fuel flow.

[0423] According to the present embodiment, the four guide sections 43 are formed circumferentially on the valve element 40. This configuration reduces eccentricity more than that of the first embodiment, which includes three guide sections 43, and offers the advantageous effect of reducing the inclination of the valve element 40. Fifth embodiment

[0424] <a-5> Fig. Figure 53 shows a part of a high-pressure pump according to a fifth embodiment. The fifth embodiment differs from the first embodiment with respect to the configuration of the discharge passage section 700.

[0425] According to the present embodiment, the discharge passage section 700 includes the seat element 31, the stopper 35, the valve element 40 and the spring 39 instead of the discharge seat element 71, the intermediate element 81, the discharge valve 75 and the spring 79.

[0426] According to the present embodiment, the end surface of the discharge port 70, which faces the pressurization chamber 200, is located on the side of the end surface of the discharge port 70 facing the pressurization chamber 200, opposite the pressurization chamber 200 in the first embodiment. In other words, the axial length of the discharge port 70 in the present embodiment is shorter than the axial length of the discharge passage section 700 in the first embodiment.

[0427] The seat element 31 is positioned in the discharge passage 217 such that a surface of the seat element 31 contacts the bottom surface of the discharge hole section 214. The seat element 31 includes a seat element recess 312. The seat element recess 312 has a substantially cylindrical shape, extending from the surface of the seat element 31 facing the pressurization chamber 200 and away from it. The seat element recess 312 is substantially coaxial with the seat element 31. The communication path 32 and the communication paths 33 pass through the seat element 31, which faces away from the pressurization chamber 200, between a bottom surface of the seat element recess 312 and the surface of the seat element 31 facing away from the pressurization chamber 200.

[0428] The configuration of the stopper 35 of the discharge passage section 700 is similar to the configuration of the stopper 35 of the intake valve unit 300. The stopper 35 is located on the side of the seat element 31 opposite the pressurization chamber 200. The surface of the large-diameter stopper section 37, which faces away from the small-diameter stopper section 36, is in contact with the outer edge of the surface of the seat element 31 that faces away from the pressurization chamber 200. The small-diameter stopper section 36 is located within the end of the discharge port 70 that faces the pressurization chamber 200. The stepped surface between the small-diameter stopper section 36 and the large-diameter stopper section 37 faces the end surface of the discharge port 70 that faces the pressurization chamber 200.The outer edge of the surface of the small-diameter stopper section 36, which is located away from the large-diameter stopper section 37, is in contact with the end surface of the cylindrical section 861 of the overflow element, which is located facing the pressurization chamber 200.

[0429] The stepped surface 701 of the discharge port 70 pre-tensions the overflow seat element 85, the stopper 35, and the seat element 31 towards the pressurization chamber 200. Accordingly, the overflow seat element 85, the stopper 35, and the seat element 31 are in contact with each other to regulate axial movement. The surface of the seat element 31 facing the pressurization chamber 200 is pressed against the stepped surface between the discharge port section 214 and the discharge port section 215, i.e., the periphery of the discharge port section 215 against the bottom surface of the discharge port section 214. In this case, an axial force acts in the direction from the seat element 31 towards the pressurization chamber 200 on the periphery of the discharge hole section 215 in the bottom surface of the discharge hole section 214. Accordingly, a seal can be created under high pressure using only a simple structure.High pressure can be reached.

[0430] The stopper 35 is designed such that the connecting holes 38 and the second passages 89 of the overflow seat element 85 are interconnected. According to the present embodiment, the pressurization chamber 200 is able to communicate with the high-pressure fuel pipe 8 via the discharge hole 233, the discharge hole section 215, the seat element recess 312, the communication path 32, the communication paths 33, the stopper recess 351, the stopper recess 352, the connecting holes 38, and the second passages 89.

[0431] The configurations of the valve element 40 and the spring 39 of the discharge passage section 700 are similar to the configurations of the valve element 40 and the spring 39 of the intake valve unit 300. The valve element 40 is positioned within the stopper recess 351, similar to the valve element 40 of the intake valve unit 300. The spring 39 is also positioned radially outside the stopper projection 353, similar to the spring 39 of the intake valve unit 300.

[0432] When the fuel pressure in the pressurization chamber 200 rises to a predetermined value or higher, the valve element 40 moves towards the high-pressure fuel pipe 8, while the latter resists the preload force of the spring 39. As a result, the valve element 40 is separated from the valve seats 310 and is open. Accordingly, the fuel is discharged between the pressurization chamber 200 and the seat element 31 via the seat element recess 312, the communication path 32, the communication paths 33, the valve seats 310, the stopper recess 351, the stopper recess 352, the connecting holes 38, and the secondary passages 89 towards the high-pressure fuel pipe 8.

[0433] According to the present embodiment, the cylinder 23, which forms the pressurization chamber formation section, as well as the upper housing 21, the seat element 31, and the valve element 40, which forms the discharge passage formation section, are provided as described above. The cylinder 23 defines the pressurization chamber 200, in which fuel is pressurized.

[0434] The upper housing 21 defines the discharge passage 217, through which the fuel flows that is discharged from the pressurization chamber 200.

[0435] The seat element 31 is arranged in the discharge passage 217 and includes the communication path 32 and the communication paths 33, which pass through the seat element 31 between one surface and the other surface of the seat element 31. The valve element 40, which is arranged on the side of the seat element 31 opposite the pressurization chamber 200, opens at the time of separation from the seat element 31 to allow fuel flow in the communication path 32 and the communication paths 33, and closes at the time of contact with the seat element 31 to restrict fuel flow in the communication path 32 and the communication paths 33.

[0436] The valve element 40 comprises the valve body 41, which has a plate shape and is capable of being separate from or contacting the seat element 31; the connecting holes 44, which pass through the valve body 41 between one surface and the other surface of the valve body 41; the tapered section 42, which is provided radially outside the valve body 41 and has a tapered surface configured such that the surface of the tapered section 42 facing away from the pressurization chamber 200 tapers in a direction towards the pressurization chamber 200 in relation to the axis Ax2 of the valve body 41; and the guide sections 43, which project radially outwards from the valve body 41 to divide the tapered sections 42 in the circumferential direction, and are capable ofThe movement of the valve element 40 is guided by sliding on the stopper recesses 351 of the stopper 35. The connecting holes 44 are arranged on the virtual circle VC1, which is centered on the axis Ax2 of the valve body 41.

[0437] The boundary line B1 between the inner edge of the tapered sections 42 and the outer edge of the valve body 41 is formed along the concentric circle CC1, which corresponds to the virtual circle VC1. This configuration reduces the distance between both ends of each boundary line B1 and the connecting holes 44. In this case, sections near both ends of each boundary line B1 do not impede the flow of fuel over the surface of the valve element 40. Accordingly, a sufficient fuel flow rate can be ensured for discharge from the pressurization chamber 200. Furthermore, the valve closing response sensitivity is improved by reducing the stroke of the valve element 40. Consequently, the backflow rate decreases, thus ensuring a sufficient discharge volume from the high-pressure pump 10.

[0438] Therefore, in the present embodiment an example is shown in which the valve element 40 with a plurality of seats or multi-seat valve element is used as the discharge valve in the discharge passage 217. Sixth embodiment

[0439] <a-6> Fig. Figure 54 shows a part of a high-pressure pump according to a sixth embodiment. The sixth embodiment differs from the first embodiment with respect to the configuration of the valve element 40.

[0440] According to the present embodiment, the valve element 40 is configured such that one surface 401, i.e., the side surface of the seat element 31, and the other surface 402, i.e., the side surface of the pressurization chamber 200, are curved in the axial direction in a cross-section that is formed along the virtual plane VP1, which includes the axis Ax2 of the valve body 41. Both the surface 401 and the surface 402 of the valve element 40 are configured to project towards the seat element 31. In other words, the valve element 40 is configured to curve from its center point towards the side of the pressurization chamber 200 when approaching its radial outer surface.

[0441] According to the valve element 40, both a curvature value QC1 of one surface 401 in the axial direction and a curvature value QC2 of the other surface 402 are set to a value that is smaller than a minimum value DL1 of the distance between the valve element 40 and the seat element 31 when the valve element 40 separates from the seat element 31. The minimum value DL1 is equivalent to the distance between one surface 401 of the valve element 40 and the side surface of the pressurizing chamber 200 of the seat element 31 on the axis Ax2 of the valve body 41 when the other surface 402 of the valve element 40 is in contact with the stopper projection 353 (compare Fig. 54). According to the present embodiment, the curvature amount QC1 and the curvature amount QC2 are balanced.

[0442] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is excited to a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure of the fuel in the pressurization chamber 200 is applied to the other surface 402 of the valve element 40. Accordingly, the outer edge of the valve element 40 is deformed towards the seat element 31, so that one surface 401 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31, i.e., a plurality of valve seats 310, as indicated by a dashed line in Fig. Figure 54 is shown. As a result, valve element 40 is closed.

[0443] According to the present embodiment, one surface 401 of the valve element 40 is curved and projects towards the seat element 31, as described above. In this case, assuming that the minimum value DL1 is a stroke QL1 of the valve element 40, the apparent stroke of the valve element 40 is greater than the stroke QL1 by a curvature QC1 at the outer edge of the valve element 40. Accordingly, the intake quantity of fuel into the fuel chamber 200, the return quantity of fuel from the pressurization chamber 200 to the fuel chamber 260, and the self-closing limit of the valve element 40 are improved.

[0444] As described above, in the present embodiment (A6), the valve element 40 is configured such that one surface 401, which is the side surface of the seat element 31, is curved in a cross-section along the virtual plane VP1, which includes the axis Ax2 of the valve body 41. In this case, the apparent stroke of the valve element 40 increases in a portion of the valve element 40 by the amount of curvature of one surface 401. Accordingly, the intake quantity of fuel into the fuel chamber 200, the return quantity of fuel from the pressurization chamber 200 to the fuel chamber 260, and the self-closing limit of the valve element 40 are improved.Accordingly, the stroke of the valve element 40 can be reduced to ensure the same performance, which can result in a reduction of the power consumption of the electromagnetic drive unit 500 and a reduction of NV.

[0445] (A7) According to the present embodiment, the valve element 40 is designed such that the curvature QC1 of one surface 401, which is the side surface of the seat element 31, is set to a value that is smaller than the minimum value DL1 of the distance between the valve element 40 and the seat element 31 when the valve element 40 separates from the seat element 31.

[0446] (A8) According to the present embodiment, the valve element 40 is configured such that one surface 401, which is the side surface of the seat element 31, projects towards the seat element 31. The present embodiment shows an example of a specific configuration of the valve element 40. Seventh embodiment

[0447] <a-7> Fig. Figure 55 shows a part of a high-pressure pump according to a seventh embodiment. The seventh embodiment differs from the first embodiment with respect to the configuration of the valve element 40.

[0448] According to the present embodiment, the valve element 40 is configured such that one surface 401, i.e., the side surface of the seat element 31, and the other surface 402, i.e., the side surface of the pressurization chamber 200, are curved in the axial direction in a cross-section that is formed along the virtual plane VP1, which includes the axis Ax2 of the valve body 41. The one surface 401 and the other surface 402 of the valve element 40 are configured to project towards the pressurization chamber 200. In other words, the valve element 40 is configured to curve from its center point towards the seat element 31 when approaching its radial outer surface.

[0449] According to the valve element 40, both a curvature value QC1 of one surface 401 in the axial direction and a curvature value QC2 of the other surface 402 are set to a value that is smaller than a minimum value DL1 of the distance between the valve element 40 and the seat element 31 when the valve element 40 separates from the seat element 31. The minimum value DL1 is equivalent to the distance between the outer edge of one surface 401 of the valve element 40 and the side surface of the pressurizing chamber 200 of the seat element 31 when the other surface 402 of the valve element 40 is in contact with the stopper projection 353 (compare Fig. 55). According to the present embodiment, the curvature amount QC1 and the curvature amount QC2 are balanced.

[0450] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is excited to a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure of the fuel in the pressurization chamber 200 is applied to the other surface 402 of the valve element 40. Accordingly, a central section of the valve element 40 is deformed towards the seat element 31, so that one surface 401 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31, i.e., a plurality of valve seats 310, as indicated by a dashed line in Fig. Figure 55 is shown. As a result, valve element 40 is closed.

[0451] According to the present embodiment, one surface 401 of the valve element 40 is curved and projects towards the pressurization chamber 200, as described above. In this case, assuming that the minimum value DL 1 is the stroke QL1 of the valve element 40, the apparent stroke of the valve element 40 is greater than the stroke QL1 by the curvature QC1 at the central section of the valve element 40. Accordingly, the intake quantity of fuel into the fuel chamber 200, the return quantity of fuel from the pressurization chamber 200 to the fuel chamber 260, and the self-closing limit of the valve element 40 are improved. Eighth embodiment

[0452] <a-8> Fig. Figure 56 shows a part of a high-pressure pump according to an eighth embodiment. The eighth embodiment differs from the sixth embodiment with respect to the configuration of the valve element 40.

[0453] According to the present embodiment, the other surface 402, which is the side surface of the pressurization chamber 200 of the valve element 40, has a flat shape. Accordingly, the curvature of the other surface 402 is zero.

[0454] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is excited to a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure of the fuel in the pressurization chamber 200 is applied to the other surface 402 of the valve element 40. Accordingly, the outer edge of the valve element 40 is deformed towards the seat element 31, so that one surface 401 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31, i.e., a plurality of valve seats 310, as indicated by a dashed line in Fig. Figure 56 is shown. As a result, valve element 40 is closed.

[0455] According to the present embodiment, one surface 401 of the valve element 40 is curved similarly to the sixth embodiment and projects towards the seat element 31. Accordingly, advantageous effects similar to those of the sixth embodiment can be achieved. Ninth embodiment

[0456] <a-9> Fig. Figure 57 shows part of a high-pressure pump according to a ninth embodiment. The ninth embodiment differs from the seventh embodiment with respect to the configuration of the valve element 40.

[0457] According to the present embodiment, the other surface 402, which is the side surface of the pressurization chamber 200 of the valve element 40, has a flat shape. Accordingly, the curvature of the other surface 402 is zero.

[0458] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is excited to a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure of the fuel in the pressurization chamber 200 is applied to the other surface 402 of the valve element 40. Accordingly, a central section of the valve element 40 is deformed towards the seat element 31, so that one surface 401 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31, i.e., a plurality of valve seats 310, as indicated by a dashed line in Fig. Figure 57 is shown. As a result, valve element 40 is closed.

[0459] According to the present embodiment, one surface 401 of the valve element 40 is curved similarly to the seventh embodiment and projects towards the pressurization chamber 200. Accordingly, advantageous effects similar to those of the seventh embodiment can be achieved. Tenth embodiment

[0460] <a-10> Fig. Figure 58 shows a part of a high-pressure pump according to a tenth embodiment. The tenth embodiment differs from the first embodiment with respect to the configuration of the valve element 40.

[0461] According to the present embodiment, each of the guide sections 43 of the valve element 40 is configured such that the side surface of the seat element 31 and the side surface of the pressurization chamber 200 are curved in a cross-section along the virtual plane VP1, which includes the axis Ax2 of the valve body 41, extending from the valve body 41 towards the pressurization chamber 200. In other words, each of the guide sections 43 is configured to curve from the valve body 41 towards the pressurization chamber 200 when near the radial outer surface.

[0462] Both a curvature value QC3 of the side surface of the seat element 31 and a curvature value QC4 of the side surface of the pressurization chamber 200 of each of the guide sections 43 are set to a value that is smaller than the minimum value DL1 of the distance between the valve element 40 and the seat element 31 when the valve element 40 separates from the seat element 31. The minimum value DL1 is equivalent to the distance between one surface 401 of the valve element 40 and the side surface of the pressurization chamber 200 of the seat element 31 on the axis Ax2 of the valve body 41 when the other surface 402 of the valve element 40 is in contact with the stopper projection 353 (compare Fig. 58). According to the present embodiment, the curvature amount QC3 and the curvature amount QC4 are balanced.

[0463] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is excited to a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure from the fuel in the pressurization chamber 200 is applied to the side surface of the guide section 43 of the pressurization chamber 200. Accordingly, each of the guide sections 43 of the valve element 40 is deformed towards the seat element 31, so that the side surface of the seat element 31 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31, i.e., the valve seats 310, as indicated by a dashed line in Fig. Figure 58 is shown. As a result, valve element 40 is closed.

[0464] According to the present embodiment, the side surface of the seat element 31 of the guide section 43 of the valve element 40 is curved from the valve body 41 towards the pressurization chamber 200, as described above. In this case, assuming that the minimum value DL1 is the stroke QL1 of the valve element 40, the apparent stroke of the valve element 40 is greater than the stroke QL1 by the curvature QC3 at the guide section 43 of the valve element 40. Accordingly, the intake quantity of fuel into the fuel chamber 200, the return quantity of fuel from the pressurization chamber 200 to the fuel chamber 260, and the self-closing limit of the valve element 40 are improved. Eleventh embodiment

[0465] <a-11> Fig. Figure 59 shows a part of a high-pressure pump according to an eleventh embodiment. The eleventh embodiment differs from the tenth embodiment with respect to the configuration of the valve element 40.

[0466] According to the present embodiment, each of the guide sections 43 of the valve element 40 is configured such that the side surface of the seat element 31 and the side surface of the pressurization chamber 200 are curved in a cross-section along the virtual plane VP1, which includes the axis Ax2 of the valve body 41, extending from the valve body 41 towards the seat element 31. In other words, each of the guide sections 43 is configured to curve from the valve body 41 towards the seat element 31 when near the radial outer surface.

[0467] Both a curvature value QC3 of the side surface of the seat element 31 and a curvature value QC4 of the side surface of the pressurization chamber 200 of each of the guide sections 43 are set to a value that is smaller than the minimum value DL1 of the distance between the valve element 40 and the seat element 31 when the valve element 40 separates from the seat element 31. The minimum value DL1 is equivalent to the distance between the end of the side surface of the seat element 31 of the guide section 43 on the side opposite the valve body 41 and the side surface of the pressurization chamber 200 of the seat element 31 when the other surface 402 of the valve element 40 is in contact with the stopper projection 353 (compare Fig. 59). According to the present embodiment, the curvature amount QC3 and the curvature amount QC4 are balanced.

[0468] According to the present embodiment, the needle 53 moves to the side opposite the pressurization chamber 200 when the coil 60 of the electromagnetic drive unit 500 is energized in a state of one degree with respect to the volume of the pressurization chamber 200 by a displacement of the plunger 11 towards the pressurization chamber 200. In this case, the valve element 40 moves in the closing direction. At this time, pressure from the fuel in the pressurization chamber 200 is applied to the side surface of the guide section 43 of the pressurization chamber 200. Accordingly, each of the guide sections 43 of the valve element 40 is deformed towards the pressurization chamber 200, so that the side surface of the seat element 31 of the valve body 41 comes into close contact with the side surface of the pressurization chamber 200 of the seat element 31.a majority of the valve seats 310 come as shown by a dashed line in . Fig. Figure 59 is shown. As a result, valve element 40 is closed.

[0469] According to the present embodiment, the side surface of the seat element 31 of the guide section 43 of the valve element 40 is curved from the valve body 41 towards the seat element 31, as described above. In this case, assuming that the minimum value DL1 is the stroke QL1 of the valve element 40, the apparent stroke of the valve element 40 is greater than the stroke QL1 by the amount of curvature QC3 at the valve body 41 of the valve element 40. Accordingly, the intake quantity of fuel into the fuel chamber 200, the return quantity of fuel from the pressurization chamber 200 to the fuel chamber 260, and the self-closing limit of the valve element 40 are improved. Twelfth embodiment

[0470] <a-12>The Fig. 60 and Fig. Figure 61 shows a part of a high-pressure pump according to a twelfth embodiment. The twelfth embodiment differs from the first embodiment with respect to the configuration of the cylinder 23.

[0471] According to the present embodiment, the outer peripheral recess 235 is formed by a predetermined distance in the axial direction of the cylinder 23, as viewed in the axial direction of the intake port 232, in a region extending from a position slightly towards the side of the bottom section of the cylinder 23 with respect to the upper end of the tapered surface 234 to a position away from the lower end of the tapered surface 234 towards the side opposite the bottom section of the cylinder 23. Accordingly, the outer peripheral recess 235 of the present embodiment is designed to encompass the entire tapered surface 234, as viewed in the axial direction of the intake port 232, and is larger than the outer peripheral recess 235 of the first embodiment in the axial direction of the cylinder 23.Similar to the first embodiment, at least part of the outer peripheral recess 235 is formed in an area which overlaps with the sliding surface 230a in the axial direction in a lower section of the cylinder 23, as viewed in the axial direction of the intake hole 232 (compare . Fig. 60).

[0472] The outer peripheral recess 236 is formed by a predetermined distance in the axial direction of the cylinder 23, as viewed in the axial direction of the discharge hole 233, in a region extending from a position slightly on the side of the bottom section of the cylinder 23 with respect to the upper end of the discharge hole 233 to a position away from the lower end of the discharge hole 233 towards the side opposite the bottom section of the cylinder 23. Accordingly, the outer peripheral recess 236 of the present embodiment is designed to encompass the entire discharge hole 233, as viewed in the axial direction of the discharge hole 233, and is larger than the outer peripheral recess 236 of the first embodiment in the axial direction of the cylinder 23.Similar to the first embodiment, at least part of the outer peripheral recess 236 is formed in an area which overlaps with the sliding surface 230a in the axial direction in a lower section of the cylinder 23, as viewed in the axial direction of the discharge hole 233 (compare . Fig. 61).

[0473] Similar to the first embodiment, the outer peripheral recesses 235 and 236 are formed in a region that extends from a section adapted to the upper housing 21, i.e., a shrink-fit section, in an axially upper section of the cylinder 23, as viewed in the axial direction of the intake port 232 or the exhaust port 233 (compare the Fig. 60 and Fig. 61). However, the size of the fitting section with the upper housing 21 is smaller than that of the first embodiment.

[0474] According to the present embodiment, the outer peripheral recess 235 and the outer peripheral recess 236 are formed in the outer peripheral wall of the cylinder 23 similarly to the first embodiment. In this case, the surface pressure produced by this deformation and applied to the outer peripheral wall of the cylinder 23 can be reduced, even if the inner peripheral wall of the hole section 211 of the upper housing 21 is deformed radially inwards during the screwing of the cylindrical element 51 of the electromagnetic drive unit 500 into the intake hole section 212 of the upper housing 21 and during the screwing of the discharge port 70 of the discharge passage section 700 into the discharge ...

Claims

[1] High-pressure pump (10), comprising: a pressurization chamber formation section (23) which defines a pressurization chamber (200) in which fuel is pressurized; a discharge passage formation section (21) defining a discharge passage (217) through which the fuel flows which is discharged from the pressurization chamber (200); a discharge seat element (71) arranged in the discharge passage (217), wherein the discharge seat element (71) comprises the following: a discharge hole (73) passing through the discharge seat element (71) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); and a discharge valve seat (74) located around the discharge hole (73) on the other surface of the discharge seat element (71), which is arranged facing away from the pressurization chamber (200); an intermediate element (81) arranged on one side of the discharge seat element (71) opposite the pressurization chamber (200), wherein the intermediate element (81) includes a first passage (83) passing through the intermediate element (81) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); an overflow seat element (85) arranged on one side of the intermediate element (81) opposite the pressurization chamber (200), wherein the overflow seat element (85) comprises the following: an overflow hole (87) passing through the overflow seat element (85) between a surface facing the pressurization chamber (200) and the other surface facing away from the pressurization chamber (200); an overflow valve seat (88) is located around the overflow hole (87) on one surface of the overflow seat element (85) that faces the pressurization chamber (200); and a second passage (89) through the overflow seat element (85) between one surface which is arranged facing the pressurization chamber (200) and the other surface which is arranged away from the pressurization chamber (200); a drain valve (75) arranged between the intermediate element (81) and the drain seat element (71), wherein the drain valve (75) is able to allow fuel flow through the drain hole (73) by separating from the drain valve seat (74) to open the drain hole (73), and to restrict fuel flow through the drain hole (73) by contacting the drain valve seat (74) to close the drain hole (73); and a bypass valve (91) arranged between the intermediate element (81) and the bypass seat element (85), wherein the bypass valve (91) is able to allow fuel flow through the bypass hole (87) by separating from the bypass valve seat (88) to open the bypass hole (87), and to restrict fuel flow through the bypass hole (87) by contacting the bypass valve seat (88) to close the bypass hole (87), wherein at least one selected from the intermediate element (81) and the overflow seat element (85) includes an annular recess (800) which has an annular shape and fluidly connects the first passage (83) and the second passage (89), and the annular recess (800) is recessed starting from a surface of the at least one selected from the intermediate element (81) and the overflow seat element (85), which are arranged facing each other, wherein the annular recess (800) is arranged between the first passage (83) and the second passage (89) and is in direct fluid communication with both the first passage (83) and the second passage (89). [2] High pressure pump (10) according to claim 1, wherein the first passage (83) is selected from a plurality of first passages arranged in a circumferential direction of the intermediate element (81), and the second passage (89) is one selected from a plurality of second passages arranged in a circumferential direction of the overflow seat element (85). [3] High pressure pump (10) according to claim 2, wherein a number of the plurality of first passages (83) differs from a number of the plurality of second passages (89). [4] High pressure pump (10) according to claim 3, wherein the number of first plural passages (83) is greater than the number of second plural passages (89), and the ring-shaped recess (800) is formed in the intermediate element (81). [5] High pressure pump (10) according to claim 4, wherein the number of the plurality of first passages (83) and the number of the plurality of second passages (89) are relatively prime. [6] High pressure pump (10) according to one of claims 1 to 5, wherein the number of a plurality of first passages (83) is greater than the number of a plurality of second passages (89), and a length of each of the plurality of first passages (83) is less than a length of each of the plurality of second passages (89). [7] High-pressure pump (10) according to any one of claims 1 to 6, further comprising a discharge port (70) having a cylindrical shape to enclose the discharge seat element (71), the intermediate element (81), the overflow seat element (85), the discharge valve (75) and the overflow valve (91), wherein The drainage port (70) includes an outer peripheral wall which is joined to the drainage passage formation section (21).

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