High pressure fuel supply pump

Abstract

The high-pressure fuel supply pump of the present invention prevents splashes from invading the interior of the pump and reduces the stress generated by the space portion provided for the weld. In the high-pressure fuel supply pump (1), a discharge nipple (19) is installed in a mounting hole portion (1h) provided in a pump body (1a) via a weld (90). A space portion (91) is formed from the terminal portion (90b) of the weld to the depth side of the mounting hole portion. The discharge nipple has an end face (71) in the depth direction of the mounting hole portion and an outer peripheral surface (72) rising from the end face. The wall surface of the mounting hole portion has an opposing surface (81) opposite to the end face and an inner peripheral surface (82) located outside the outer peripheral surface and extending from the opposing surface to the terminal portion of the weld. The end face and the opposing surface form a gap (C) of a specified range. The space portion is formed from the terminal portion of the weld to the opposing surface. In the inner peripheral surface, the entirety from the terminal portion of the weld to the opposing surface is formed as a concave curved surface, constituting the wall surface of the space portion.

Description

Technical Field

[0001] The present invention relates to a high-pressure fuel supply pump, and more particularly to a high-pressure fuel supply pump in which a functional component such as a discharge joint is joined by welding to a pump body having a pressurizing chamber for pressurizing fuel. Background Art

[0002] In internal combustion engines such as automobiles, direct injection internal combustion engines that directly inject fuel into the combustion chamber widely use high-pressure fuel supply pumps for pressurizing fuel. In some high-pressure fuel supply pumps, a pump body having a pressurizing chamber for pressurizing fuel is joined to functional components such as a discharge nipple and an electromagnetic suction valve mechanism by welding (for example, see Patent Document 1).

[0003] In the high-pressure fuel supply pump described in Patent Document 1, a discharge joint is inserted into a hole formed on the outer peripheral surface of the pump body, and the inner peripheral portion of the hole of the pump body and the outer peripheral portion of the discharge joint are fixed by welding on their contact surfaces. For the welding portion that joins the pump body and the discharge joint, a space is formed on the side opposite to the outer peripheral surface of the pump body. The space is a structure that prevents the formation of a notch with an acute angle that causes stress concentration, a notch with a small corner radius, etc. at the terminal end of the welding portion. The space is formed, for example, by the annular recessed shape of the pump body and the annular recessed shape of the discharge joint. In addition, in the high-pressure fuel supply pump described in Patent Document 1, the inner peripheral portion of the hole of the pump body and the outer peripheral portion of the discharge joint are brought into contact at a position closer to the depth side of the hole than the above-mentioned space, thereby preventing splashes generated during welding (such as welding) from intruding into the interior of the pump body.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-066956 Summary of the invention

[0007] Technical issues to be solved by the invention

[0008] However, in recent years, there has been a demand for further increasing the pressure of fuel in order to further improve fuel efficiency.

[0009] Therefore, the strength of the welded portion between the discharge joint and the pump body and the vicinity thereof also needs to be increased in accordance with the increase in fuel pressure.

[0010] However, in the high-pressure fuel supply pump described in Patent Document 1, there is a risk that the maximum stress generated in the annular recessed shape of the pump body forming the above-mentioned space will exceed the material strength due to the further increase in the pressure of the fuel. In order to reduce the maximum stress of the annular recessed shape, it is effective to increase the radius of curvature of the contour curve (roughly a semicircular curve) of the cross section obtained by cutting the annular recessed shape on a surface orthogonal to the annular direction. However, in order to prevent splashes from invading the interior of the pump body, the inner periphery of the hole portion of the pump body is brought into contact with the outer periphery of the discharge joint at a position closer to the hole depth side than the annular recessed shape of the pump body and the discharge joint. Therefore, in the current structure, it is difficult to further increase the radius of curvature of the contour curve of the annular recessed shape of the pump body.

[0011] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a high-pressure fuel supply pump that can prevent splashes from entering the pump interior and reduce stress generated in a portion forming a space provided for a welded portion.

[0012] Technical solutions to solve problems

[0013] The present invention includes a variety of means for solving the above-mentioned problems. For example, the present invention is characterized in that it includes: a pump body having a hole portion on its outer surface; a functional component installed in the hole portion of the pump body; and a welding portion that connects the pump body and the functional component, a space portion is formed between the pump body and the functional component from the terminal end portion of the welding portion in the melting direction to the depth side of the hole portion of the pump body, and the functional component has: an end face in the depth direction of the hole portion; and an outer peripheral surface rising from the outer edge of the end face, and the wall surface of the hole portion forming the pump body has: The opposing surface of the functional component is opposite to the end surface; and the inner circumferential surface located outside the outer circumferential surface of the functional component and reaching the terminal portion of the welding portion from the outer edge of the opposing surface, the end surface of the functional component and the opposing surface of the pump body form a gap of a size within a prescribed range, the space portion is formed in the range from the terminal portion of the welding portion to the opposing surface of the pump body, and the entirety of the inner circumferential surface of the pump body from the terminal portion of the welding portion to the opposing surface is formed as a concave surface, which constitutes a part of the wall surface of the space portion.

[0014] Effects of the Invention

[0015] According to the present invention, the combination of the end surface of the functional component and the opposing surface of the pump body opposite thereto prevents splashes from intruding into the pump interior, so that the space portion provided for the weld portion is extended to the range of the opposing surface of the pump body, thereby reducing the curvature of the concave curved surface of the inner peripheral surface of the pump body forming the space portion. Thus, splashes can be prevented from intruding into the pump interior, and the stress generated on the inner peripheral surface of the pump body forming the space portion can be reduced.

[0016] Other problems, structures, and effects than those described above will become more apparent through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram showing the configuration of a fuel supply system of an internal combustion engine including a high-pressure fuel supply pump according to an embodiment of the present invention.

[0018] Figure 2 It is a longitudinal sectional view showing a high-pressure fuel supply pump according to a first embodiment of the present invention.

[0019] Figure 3 The high pressure fuel supply pump of the first embodiment of the present invention is connected with Figure 2 The longitudinal sectional views shown are longitudinal sectional views cut at different cross sections.

[0020] Figure 4 It is viewed from IV-IV Figure 2 2 is a cross-sectional view of a high-pressure fuel supply pump according to a first embodiment of the present invention.

[0021] Figure 5 It is shown in an enlarged state Figure 4 A cross-sectional view of a joint structure between a discharge joint and a pump body, as shown by symbol Z.

[0022] Figure 6 It is a cross-sectional view showing in an enlarged state the joining structure between the discharge joint and the pump body in the high-pressure fuel supply pump according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0023] Hereinafter, an embodiment of the high-pressure fuel supply pump of the present invention will be described using the drawings. First, the structure of a fuel supply system of an internal combustion engine including the high-pressure fuel supply pump of the embodiment of the present invention will be described using the drawings. Figure 1 Provide explanation. Figure 1 It is a diagram showing the configuration of a fuel supply system of an internal combustion engine including a high-pressure fuel supply pump according to an embodiment of the present invention.

[0024] Figure 1 In the figure, the portion surrounded by the dotted line represents the main body of the high-pressure fuel supply pump, that is, the pump body. The mechanism and components shown in the dotted line represent those installed on the pump body. Figure 1 is a diagram schematically showing the structure of a fuel supply system. Figure 1 The structure of the high pressure fuel supply pump shown is similar to that described later. Figure 2 The structure shown below is different from that shown below.

[0025] Figure 1In the embodiment, the fuel supply system of the internal combustion engine includes, for example, a fuel container 101 for storing fuel, a feed pump 102 for drawing and delivering the fuel in the fuel container 101, a high-pressure fuel supply pump 1 for pressurizing the fuel delivered from the feed pump 102 and discharging it, and a plurality of injectors 103 for injecting the high-pressure fuel delivered by the high-pressure fuel supply pump 1. The high-pressure fuel supply pump 1 is connected to the feed pump 102 via a suction pipe 104, and is connected to the injectors 103 via a common rail 105. The injectors 103 are installed on the common rail 105 in accordance with the number of cylinders of the engine. A pressure sensor 106 for detecting the pressure of the fuel discharged from the high-pressure fuel supply pump 1 is installed on the common rail 105. This system is a system for directly injecting fuel into the cylinders of the engine, that is, a direct injection engine system.

[0026] The high-pressure fuel supply pump 1 includes a pump body 1a having a pressurizing chamber 3 for pressurizing fuel, a plunger 4 mounted on the pump body 1a, an electromagnetic suction valve mechanism 300, and a discharge valve mechanism 500. The plunger 4 pressurizes the fuel in the pressurizing chamber 3 by reciprocating motion. The electromagnetic suction valve mechanism 300 functions as a capacity adjustment mechanism for adjusting the flow rate of fuel sucked into the pressurizing chamber 3. The discharge valve mechanism 500 discharges the fuel pressurized by the plunger 4 to the common rail 105 side. On the upstream side of the electromagnetic suction valve mechanism 300, a pressure pulsation reduction mechanism 12 is provided to reduce the influence of the pressure pulsation generated in the high-pressure fuel supply pump 1 on the suction piping 104.

[0027] The feed pump 102, the electromagnetic suction valve mechanism 300 of the high-pressure fuel supply pump 1, and the injector 103 are electrically connected to an engine control unit (hereinafter referred to as ECU) 107 and controlled by a control signal output by the ECU 107. The detection signal from the pressure sensor 106 is input to the ECU 107.

[0028] In the fuel supply system, the fuel in the fuel container 101 is drawn by the feed pump 102 driven by the control signal of the ECU 107. The fuel is pressurized to an appropriate feed pressure by the feed pump 102 and sent to the low-pressure fuel suction port 2a of the high-pressure fuel supply pump 1 through the suction pipe 104. The fuel after passing through the low-pressure fuel suction port 2a reaches the electromagnetic suction valve mechanism 300 via the pressure pulsation reduction mechanism 12 and the suction passage 2d. The fuel flowing into the electromagnetic suction valve mechanism 300 passes through the opening opened and closed by the suction valve 30. The fuel is sucked into the pressurizing chamber 3 during the descending stroke of the reciprocating plunger 4, and is pressurized in the pressurizing chamber 3 during the ascending stroke of the plunger 4. The pressurized fuel is pressure-sent to the common rail 105 from the discharge valve mechanism 500 through the fuel discharge port 2h. The high-pressure fuel in the common rail 105 is injected into each cylinder of the engine by each injector 103 driven by the control signal of the ECU 107. The high-pressure fuel supply pump 1 opens and closes the intake valve 30 of the electromagnetic intake valve mechanism 300 in accordance with a control signal output from the ECU 107 to the electromagnetic intake valve mechanism 300 , thereby discharging a required fuel flow rate.

[0029] [First embodiment]

[0030] Next, use Figure 2 to Figure 4 The structure of each part of the high-pressure fuel supply pump according to the first embodiment of the present invention will be described. Figure 2 It is a longitudinal sectional view showing a high-pressure fuel supply pump according to a first embodiment of the present invention. Figure 3 The high pressure fuel supply pump of the first embodiment of the present invention is connected with Figure 2 The longitudinal sectional views shown are longitudinal sectional views obtained by cutting at different cross sections. Figure 4 It is viewed from IV-IV Figure 2 2 is a cross-sectional view of a high-pressure fuel supply pump according to a first embodiment of the present invention.

[0031] Figure 2 to Figure 4 In the embodiment, the high-pressure fuel supply pump 1 includes a pump body 1a having a pressurizing chamber 3 for pressurizing fuel inside, a plunger 4 mounted on the pump body 1a, and an electromagnetic suction valve mechanism 300 (in Figure 2 and Figure 4 Figure), discharge valve mechanism 500 (only in Figure 4 Figure), pressure relief valve mechanism 600 (only in Figure 2 The high-pressure fuel supply pump 1 is connected to a pump mounting portion 111 (in the figure) of the engine via a mounting flange 1b provided on a pump body 1a. Figure 2 and Figure 3 An O-ring 15 (in the figure) is embedded in the outer peripheral surface of the pump body 1a that is embedded in the pump mounting portion 111. Figure 2 and Figure 3The O-ring 15 seals between the pump mounting portion 111 and the pump body 1a to prevent the engine oil and the like from leaking to the outside of the engine.

[0032] In the central part of the pump body 1a, as shown in FIG. Figure 2 and Figure 3 As shown, there is formed in the length direction ( Figure 2 and Figure 3 The insertion hole portion 1d extending in the vertical direction in the middle (in the vertical direction) is installed by pressing the cylinder 5 into the insertion hole portion 1d. The cylinder 5 guides the reciprocating motion of the plunger 4 and forms a part of the pressurized chamber 3 together with the pump body 1a. The fixing portion 1c provided at the opening edge of the insertion hole portion 1d of the pump body 1a is engaged with the axial center portion of the cylinder 5. The fixing portion 1c pushes the cylinder 5 toward the pressurized chamber 3 so as to seal the pressurized chamber 3 in such a manner that the fuel pressurized in the pressurized chamber 3 does not leak to the low-pressure side from between the end surface of the cylinder 5 and the wall surface of the insertion hole portion 1d of the pump body 1a.

[0033] On the front end side of the plunger 4 ( Figure 2 and Figure 3 The lower end side of the cylinder 5 is provided with a tappet 6. The tappet 6 converts the rotational motion of the cam 112 mounted on the camshaft (not shown) of the engine into a linear reciprocating motion and transmits it to the plunger 4. The plunger 4 is pressed against the tappet 6 by the force of the spring 8 through the retainer 7. As a result, the tappet 6 reciprocates with the rotational motion of the cam 112, and the plunger 4 reciprocates along the cylinder 5, and the volume of the pressurized chamber 3 increases or decreases.

[0034] A sealing member 9 having a bottomed cylindrical portion is fixed to the pump body 1a at a position closer to the engine than the cylinder 5, and the plunger 4 passes through the bottom of the sealing member 9. A sub-chamber 9a is formed inside the sealing member 9 for storing fuel leaking from the pressurizing chamber 3 through the sliding portion between the plunger 4 and the cylinder 5.

[0035] On the bottom side of the interior of the sealing holder 9 ( Figure 2 and Figure 3 The plunger seal 10 is held on the lower end side of the plunger 4. The plunger seal 10 is arranged in a manner that the outer peripheral surface of the plunger 4 can slide in contact. The plunger seal sleeve 10 prevents the fuel in the sub-chamber 9a from flowing out to the engine side when the plunger 4 reciprocates. At the same time, it prevents the lubricating oil (including the engine oil) in the engine from flowing into the interior of the pump body 1a from the engine side.

[0036] In addition, at the front end portion ( Figure 2 and Figure 3 A cup-shaped cover 13 is mounted on the upper end of the pump body 1a. The front end of the pump body 1a and the cover 13 form a low-pressure fuel chamber 2c.

[0037] A pressure pulsation reduction mechanism 12 is arranged in the low-pressure fuel chamber 2c. The pressure pulsation reduction mechanism 12 is composed of, for example, two dampers 12a and a plurality of retaining members 12b for retaining the two dampers 12a in the low-pressure fuel chamber 2c. In each damper 12a, two metal diaphragms are overlapped, and an inert gas is sealed in the space between the two metal diaphragms. The damper 12a reduces pressure pulsation by expanding and contracting. The plurality of retaining members 12b retain the two dampers 12a in the low-pressure fuel chamber 2c by sandwiching them between the cover 13 and the front end of the pump body 1a.

[0038] On the outer peripheral surface of the cover 13, as shown in FIG. Figure 3 As shown, a suction joint 17 having a low-pressure fuel suction port 2a is installed. The suction joint 17 is connected to a suction pipe 104 (see Figure 1 ), from the fuel container 101 (reference Figure 1 ) is supplied to the interior of the high-pressure fuel supply pump 1 via the suction joint 17. A suction filter 18 is arranged in the flow path of the suction joint 17. The suction filter 18 has the function of preventing foreign matter existing between the fuel container 101 and the low-pressure fuel suction port 2a from being absorbed into the high-pressure fuel supply pump 1 due to the flow of fuel.

[0039] like Figure 2 and Figure 4 As shown, a first mounting hole portion 1f is provided on the outer peripheral surface (outer surface) 1e of the pump body 1a. The first mounting hole portion 1f is connected to the low-pressure fuel chamber 2c via the suction passage 2d formed in the pump body 1a, and is connected to the pressurized chamber 3 via the suction passage 2e formed in the pump body 1a. An electromagnetic suction valve mechanism 300 is installed in the first mounting hole portion 1f. The electromagnetic suction valve mechanism 300 is roughly divided into a valve body unit, an armature unit, and a solenoid unit.

[0040] The valve body unit includes, for example, a suction valve 30, a suction valve seat 31, a suction valve biasing spring 32, a spring bracket 33, and a suction valve stopper 34. The suction valve 30 includes a disc-shaped valve portion 30a and a rod portion 30b extending from the center of the valve portion 30a in a direction perpendicular to the valve portion 30a. The spring bracket 33 is attached to the front end of the rod portion 30b. In the suction valve seat 31, a valve seat portion 31a on which the valve portion 30a of the suction valve 30 is seated or released and a rod guide portion 31b that slidably supports the rod portion 30b of the suction valve 30 are integrally formed.

[0041] The suction valve seat 31 is provided with a plurality of suction ports 31c that communicate with the suction passage 2d of the pump body 1a. The suction valve biasing spring 32 is disposed in the rod guide portion 31b of the suction valve seat 31, and biases the suction valve 30 toward the valve seat portion 31a side (valve closing direction) via the spring bracket 33. The suction valve stopper 34 limits the lift of the valve portion 30a of the suction valve 30.

[0042] The armature unit includes a housing 36 as a fixed part, a magnetic core 37, an armature guide 38, an armature 39 and an armature bushing 40 which are integrally assembled as a movable part, and an armature urging spring 41 which urges the movable part. The housing 36 is formed into a cylindrical shape with a bottom, and the opening is fitted with the suction valve seat 31 of the valve body unit. The magnetic core 37, the armature guide 38, the armature 39 and the armature bushing 40 are arranged in the housing 36. The magnetic core 37 is formed into a cylindrical shape and is fixed in a state of contact with the inner peripheral surface on the bottom side of the housing 36. The armature guide 38 is fixed to the bottom of the housing 36. The armature guide 38 is formed into a cylindrical shape extending from the bottom of the housing 36 to the opening, and is inserted into the inside of the magnetic core 37.

[0043] The armature 39 is formed in a cylindrical shape and is arranged so as to face the end face of the core 37 on the opening side of the housing 36 in the axial direction. The core 37 and the armature 39 are arranged on the inner peripheral side of the electromagnetic coil 44 described later of the solenoid unit, and the opposing end faces of the core 37 and the armature 39 respectively constitute magnetic attraction surfaces on which magnetic attraction forces act on each other. The armature bushing 40 is pressed into the inner peripheral side of the armature 39 and fixed, and the armature 39 and the armature bushing 40 can move integrally in the housing 36. In the armature 39 and the armature bushing 40, the outer peripheral surface of the armature 39 slides on the inner peripheral surface of the housing 36, and the armature bushing 40 slides on the outer peripheral surface of the armature guide 38, thereby guiding the movement. The movable part of the armature 39 and the armature bushing 40 is configured to be able to abut against the front end of the rod portion 30b of the suction valve 30 of the valve body unit. The armature urging spring 41 is disposed in a storage space formed between the inner circumferential surface of the magnetic core 37 and the outer circumferential surface of the armature guide 38, and one end thereof abuts against the armature guide 38 as a fixed portion, and the other end thereof abuts against the armature bushing 40 as a movable portion. The armature urging spring 41 urges the armature 39 and the armature bushing 40 as the movable portion in a direction away from the magnetic core 37. That is, when there is no magnetic attraction between the magnetic core 37 and the armature 39, a gap is generated between the magnetic core 37 and the armature 39.

[0044] On the other hand, when there is a magnetic attraction force between the magnetic core 37 and the armature 39, the armature 39 and the armature bushing 40 of the movable part move against the force of the armature urging spring 41, and the armature 39 contacts the magnetic core 37. When the armature 39 and the armature bushing 40 of the movable part move in a direction away from the magnetic core 37 due to the force of the armature urging spring 41, the suction valve 30 of the valve body unit is pushed, and the suction valve 30 leaves the suction valve seat 31 and becomes a valve-opening state. That is, the armature urging spring 41 is configured to urge the armature 39 and the armature bushing 40 of the movable part in the valve-opening direction.

[0045] The solenoid unit includes, for example, a base member 43, an electromagnetic coil 44, and a connection terminal 45. The base member 43 is fitted to the outer peripheral side of the housing 36 of the armature unit. The base member 43 is formed of a resin material or the like, and has a structure that can be connected to the ECU 107 (see Figure 1 ) is connected to the connector fitting portion of the control line of the ECU 107. The electromagnetic coil 44 is formed in a ring shape on the outer peripheral side of the housing 36 of the armature unit and is fixed to the base member 43. A portion of the connection terminal 45 is embedded in the base member 43, and one end side is electrically connected to the electromagnetic coil 44. The other end of the connection terminal 45 is exposed in the connector fitting portion of the base member 43 and can be connected to the ECU 107 (refer to Figure 1 In the high-pressure fuel supply pump 1, by controlling the timing of energizing the electromagnetic coil 44, the flow rate of the high-pressure discharged fuel can be controlled to the flow rate required by the engine.

[0046] In addition, if Figure 4 As shown in FIG. 1 , a second mounting hole portion 1g communicating with the pressurizing chamber 3 is provided at a position offset from the first mounting hole portion 1f in the circumferential direction on the outer peripheral surface (outer surface) 1e of the pump body 1a. A discharge valve mechanism 500 as a functional component is installed in the second mounting hole portion 1g. The discharge valve mechanism 500 includes, for example, a discharge valve seat 51, a discharge valve 52 capable of being seated and unseated relative to the discharge valve seat 51, a discharge valve spring 53 for urging the discharge valve 52 toward the discharge valve seat 51, and a discharge valve holder 54 for accommodating the discharge valve 52 and the discharge valve spring 53. The discharge valve holder 54 functions as a stopper for limiting the lift of the discharge valve 52.

[0047] A plug 55 is disposed at the opening of the second mounting hole 1g to close the opening. The plug 55 is welded to the side wall of the second mounting hole 1g of the pump body 1a and has a function of preventing fuel from leaking to the outside. The second mounting hole 1g in which the discharge valve mechanism 500 is disposed communicates with a fuel discharge port 2h described later via a discharge passage 2g formed in the pump body 1a.

[0048] The discharge valve mechanism 500 is configured such that when there is no fuel pressure difference between the pressurizing chamber 3 and the internal space on the secondary side of the discharge valve 52 (the internal space connected to the discharge passage 2g), the discharge valve 52 is pressed against the discharge valve seat 51 by the force of the discharge valve spring 53 and becomes a closed valve state. The discharge valve 52 is configured such that only when the fuel pressure in the pressurizing chamber 3 is greater than the fuel pressure in the internal space on the secondary side of the discharge valve 52, the discharge valve 52 will resist the force of the discharge valve spring 53 and open. The discharge valve mechanism 500 of the above structure functions as a check valve that restricts the flow direction of the fuel.

[0049] In addition, if Figure 2 and Figure 4As shown in FIG. 1 , a third mounting hole portion 1h is provided at a position on the side opposite to the first mounting hole portion 1f across the pressurized chamber 3 of the outer peripheral surface (outer surface) 1e of the pump body 1a. A discharge joint 19 as a functional component is installed in the third mounting hole portion 1h of the pump body 1a by welding. The discharge joint 19 has a fuel discharge port 2h for discharging pressurized fuel, which is connected to the common rail 105 (reference Figure 1 The details of the connection structure between the discharge joint 19 and the pump body 1a will be described later.

[0050] In the pump body 1a, as Figure 2 As shown, a pressure relief passage 2i connected to the pressurized chamber 3 and the third mounting hole portion 1h is formed. A pressure relief valve mechanism 600 is arranged across the pressure relief passage 2i and the pressurized chamber 3. The pressure relief valve mechanism 600 includes, for example, a pressure relief valve seat 61, a pressure relief valve 62 that contacts and separates from the pressure relief valve seat 61, a pressure relief valve holder 63 that holds the pressure relief valve 62, and a pressure relief spring 64 that urges the pressure relief valve 62 toward the pressure relief valve seat 61. The fuel passage of the pressure relief valve seat 61 is connected to the fuel discharge port 2h of the discharge joint 19. One end side of the pressure relief spring 64 abuts against the wall surface forming the pressurized chamber 3, and the other end side abuts against the pressure relief valve holder 63. The pressure relief valve 62 is pushed against the pressure relief valve seat 61 by the force of the pressure relief spring 64 through the pressure relief valve holder 63, thereby cutting off the flow of fuel. The valve opening pressure of the pressure relief valve 62 is determined by the force of the pressure relief spring 64.

[0051] The pressure relief valve mechanism 600 is configured to be located on the common rail 105 (reference Figure 1 ) and the previous components, and the common rail 105 reaches an abnormally high pressure. That is, the pressure relief valve mechanism 600 is configured so that when the pressure difference between the upstream side (pressurization chamber 3) and the downstream side of the pressure relief valve 62 exceeds the set pressure, the pressure relief valve 62 opens against the force of the pressure relief spring 64. The pressure relief valve mechanism 600 has a function of opening the valve and returning the fuel to the pressurization chamber 3 when the pressure in the common rail 105 increases. In addition, the pressure relief valve mechanism 600 of the present embodiment is arranged across the pressure relief passage 2i and the pressurization chamber 3, but is not limited to this. For example, the pressure relief valve mechanism 600 can be arranged in the pressure relief passage 2i that is connected to a low-pressure passage such as the low-pressure fuel chamber 2c.

[0052] Next, use Figure 2 to Figure 4 The operation of the high-pressure fuel supply pump will be described.

[0053] Figure 3 In the high-pressure fuel supply pump 1 shown in the figure, fuel flows in from the low-pressure fuel suction port 2a of the suction joint 17, and foreign matter in the fuel is removed by the suction filter 18. After that, the fuel flowing into the low-pressure fuel chamber 2c has its pressure pulsation reduced by the pressure pulsation reducing mechanism 12 in the low-pressure fuel chamber 2c, and then passes through the Figure 2The suction passage 2 d shown reaches the electromagnetic suction valve mechanism 300 .

[0054] Figure 2 When the plunger 4 shown in the figure performs a downward movement to move toward the cam 112 side due to the rotation of the cam 112, the volume of the pressurizing chamber 3 increases, and the fuel pressure in the pressurizing chamber 3 decreases. At this time, when the pressure difference between the pressurizing chamber 3 and the suction port 31c of the electromagnetic suction valve mechanism 300 is small, the suction valve 30 becomes an open state due to the armature biasing spring 41 of the electromagnetic suction valve mechanism 300. Therefore, the fuel flows into the pressurizing chamber 3 through the opening of the suction valve 30. This state is called the suction stroke.

[0055] After the plunger 4 has finished its downward movement, it turns to upward movement. Here, the electromagnetic coil 44 of the electromagnetic suction valve mechanism 300 remains in a non-energized state and does not generate magnetic force. At this time, the suction valve 30 is maintained in an open state due to the force of the armature force spring 41. The volume of the pressurized chamber 3 decreases with the upward movement of the plunger 4, but when the suction valve 30 is open, the fuel that has been sucked into the pressurized chamber 3 returns to the suction passage 2d through the opening of the suction valve 30, so the pressure in the pressurized chamber 3 does not rise. This state is called a return stroke.

[0056] During the return stroke, the electromagnetic suction valve mechanism 300 is subjected to the ECU 107 (refer to Figure 1 ) when a control signal is received, current flows to the electromagnetic coil 44 via the connection terminal 45. Thus, magnetic attraction acts between the magnetic core 37 and the armature 39 of the electromagnetic suction valve mechanism 300, and the magnetic core 37 and the armature 39 collide on the opposite magnetic attraction surfaces. The magnetic attraction overcomes the force of the armature biasing spring 41, and the movable armature 39 and the armature bushing 40 move in the valve closing direction (the direction away from the suction valve 30).

[0057] At this time, the suction valve 30 is closed by the force of the suction valve biasing spring 32 of the electromagnetic suction valve mechanism 300 and the fluid force caused by the fuel flowing into the suction passage 2d. As the suction valve 30 is closed, the fuel pressure in the pressurizing chamber 3 rises in accordance with the upward movement of the plunger 4, and when it reaches a pressure higher than the pressure of the fuel discharge port 2h, Figure 4 The discharge valve 52 of the discharge valve mechanism 500 shown in FIG. 1 is opened. As a result, the high-pressure fuel in the pressurizing chamber 3 is discharged from the fuel discharge port 2h via the discharge valve mechanism 500 and the discharge passage 2g, and is supplied to the common rail 105 (see FIG. 1 ). Figure 1 ). This state is called the discharge stroke.

[0058] The flow rate of discharged high-pressure fuel can be used to Figure 2The energization time of the electromagnetic coil 44 of the electromagnetic suction valve mechanism 300 shown in the figure is controlled. If the timing of energizing the electromagnetic coil 44 is advanced, the proportion of the return stroke in the rising movement of the plunger 4 is reduced, and the proportion of the discharge stroke is increased. That is, the fuel returned to the suction passage 2d is reduced, and the fuel discharged at high pressure is increased. In contrast, if the timing of energization is delayed, the proportion of the return stroke in the rising movement is increased, and the proportion of the discharge stroke is reduced. That is, the fuel returned to the suction passage 2d is increased, and the fuel discharged at high pressure is reduced. The energization time of the electromagnetic coil 44 is controlled by instructions from ECU107.

[0059] When the pressure at the fuel outlet 2 h exceeds the set pressure of the relief valve mechanism 600 due to some kind of failure, the pressurizing valve 62 is opened and the abnormally high-pressure fuel is released to the pressurizing chamber 3 .

[0060] In recent years, there has been a demand for further increasing the pressure of fuel in order to further improve fuel efficiency and the like.

[0061] In this embodiment, the strength of the discharge joint 19 for discharging the pressurized fuel in the vicinity of the welded portion with respect to the pump body 1 a is improved in accordance with the increase in the pressure of the fuel.

[0062] Next, the connection structure between the discharge joint and the pump body according to the first embodiment of the present invention is described using Figure 4 and Figure 5 Provide explanation. Figure 5 It is shown in an enlarged state Figure 4 A cross-sectional view of a joint structure between a discharge joint and a pump body shown by reference numeral Z.

[0063] Figure 4 In the embodiment, the discharge joint 19 is a cylindrical member having an axis X, and has a flow path 19a inside thereof through which the high-pressure fuel pressurized in the pressurizing chamber 3 flows. Figure 5 As shown, in a state where the one end portion 70 is inserted into the third mounting hole portion 1h of the pump body 1a, the pump body 1a is joined via the weld portion 90. An annular space portion 91 is formed between the pump body 1a and the one end portion 70 of the discharge nipple 19 from a terminal portion 90b described later in the melting direction D of the weld portion 90 toward the depth side of the third mounting hole portion 1h of the pump body 1a. The space portion 91 prevents the formation of a notch with an acute angle or a notch with a small corner radius, which causes stress concentration, at the terminal portion 90b of the weld portion.

[0064] The one end portion 70 of the discharge joint 19 is formed in a cylindrical shape, for example, and has an annular end surface 71 ( Figure 5The outer peripheral surface 72 is a cylindrical outer peripheral surface 72 that rises from the outer edge of the end surface 71 and reaches the terminal end 90b of the weld 90. The outer peripheral surface 72 constitutes the wall surface of the space 91 together with the inner peripheral surface 82 of the pump body 1a described later.

[0065] The one end portion 70 of the discharge nipple 19, in the state of a single component before being welded to the pump body 1a, has a tapered inclined surface 73 that is inclined relative to the cylindrical outer peripheral surface 72 in a manner that gradually expands toward the outer peripheral side as it gradually moves away from the outer peripheral surface 72. The inclined surface 73 is a portion that faces the inclined surface 87 of the pump body 1a described later, and is a portion that is melted together with a part of the pump body 1a during welding to form a welded portion 90. In addition, the discharge nipple 19, in the state of a single component, has an annular flange portion 75 that is formed in a manner that protrudes toward the outer peripheral side than the one end portion 70 and abuts against the outer peripheral surface (outer surface) 1e of the pump body 1a.

[0066] The flange portion 75 is configured so that when it contacts the outer surface of the pump body 1a, the end surface 71 of the discharge nipple 19 is arranged at a position where a small gap C described later is formed. That is, the flange portion 75 functions as a positioning portion in the insertion direction of the third mounting hole portion 1h. The flange portion 75 is also a portion that is melted together with a part of the pump body 1a during welding to form the welded portion 90, similar to the inclined surface 73.

[0067] The third mounting hole portion 1h of the pump body 1a has an axis extending in the same direction as the axis X of the discharge joint 19. The wall surface forming the third mounting hole portion 1h of the pump body 1a is as shown in FIG. Figure 5 The discharge connector 19 has an opposing surface 81 opposing the end surface 71 of the discharge connector 19, and an inner peripheral surface 82 located outside the outer peripheral surface 72 of the discharge connector 19. The opposing surface 81 constitutes, for example, the bottom surface of the third mounting hole portion 1h. The inner peripheral surface 82 constitutes the side surface of the third mounting hole portion 1h, and extends from the outer edge of the opposing surface 81 to the terminal portion 90b of the welded portion 90.

[0068] The entire inner peripheral surface 82 from the terminal end 90b of the weld 90 to the outer edge of the opposing surface 81 is formed into a concave curved surface. The entire inner peripheral surface 82 constitutes the wall surface of the space portion 91 together with the outer peripheral surface 72 of the discharge joint 19. The contour curve obtained when the inner peripheral surface 82 is cut on a plane orthogonal to the annular direction along the inner peripheral surface 82 (a meridian cross section obtained when cut on a plane including the axis of the third mounting hole portion 1h) is composed of a first curved portion 83 whose one end 83a is connected to the terminal end 90b of the weld 90, and a second curved portion 84 whose one end 84a is connected to the other end 83b of the first curved portion 83 and whose other end 84b is connected to the outer edge of the opposing surface 81. The first curved portion 83 has a first curvature radius having a relatively large curvature radius. The second curved portion 84 has a second curvature radius having a curvature radius smaller than the first curvature radius.

[0069] The contour curves (meridian cross section of the inner peripheral surface 82) 83, 84 are configured such that a first length L1 in the depth direction of the third mounting hole portion 1h from one end 83a to the other end 83b of the first curved portion 83 is longer than a second length L2 in the depth direction of the third mounting hole portion 1h from one end 84a to the other end 84b of the second curved portion 84. In addition, the contour curves (meridian cross section of the inner peripheral surface 82) 83, 84 are configured such that, in the portion surrounded by the contour curves 83, 84, the line segment LS ( Figure 5 A perpendicular line PL ( Figure 5 The first area S1 enclosed by the vertical line PL and the first curved portion 83 is larger than the second area S2 enclosed by the vertical line PL and the second curved portion 84. Point F is the foot of the vertical line PL.

[0070] In the pump body 1a, before the discharge nipple 19 is welded, the side surface of the third mounting hole portion 1h has a cylindrical guide surface 86 connected to the end of the opening side of the inner peripheral surface 82, and an inclined surface 87 connected to the guide surface 86 at one end and connected to the outer peripheral surface (outer surface) 1e at the other end. The guide surface 86 is formed so that the outer peripheral surface 72 of the one end 70 of the discharge nipple 19 can slide thereon when the one end 70 is inserted into the third mounting hole portion 1h, and has a guide function to guide the one end 70. The guide surface 86 is a portion that is melted together with a part of the discharge nipple 19 during welding to form the welded portion 90. The inclined surface 87 is formed in a tapered shape that is inclined relative to the cylindrical guide surface 86 so as to gradually expand toward the outer peripheral side as it gradually moves away from the guide surface 86. The inclined surface 87 is a portion that faces the inclined surface 73 of the discharge nipple 19 and is a portion that is melted together with a part of the discharge nipple 19 during welding to form the welded portion 90.

[0071] The weld 90 is formed by, for example, melting the pump body 1a and the discharge nipple 19 by laser welding in a state where the inclined surface 87 of the pump body 1a is butted against the inclined surface 73 of the discharge nipple 19. Therefore, the melting direction D of the weld 90 is along the inclined surface 87 of the pump body 1a and the inclined surface 73 of the discharge nipple 19. The weld 90 is formed from the outer peripheral surface (outer surface) 1e of the pump body 1a and the outer surface of the flange portion 75 of the discharge nipple 19 to the range reaching the space 91. That is, the starting end 90a of the melting direction of the weld 90 is formed on the outer peripheral surface (outer surface) 1e of the pump body 1a and the outer surface side of the flange portion 75 of the discharge nipple 19, and the terminal end 90b of the melting direction D of the weld 90 is formed in the space 91. A part of the terminal end 90b of the weld 90 constitutes a very small part of the wall surface of the space 91.

[0072] In the present embodiment, a small gap C of a size within a predetermined range is formed by the opposing surfaces 81 of the pump body 1a and the end surface 71 of the discharge nipple 19. The small gap C prevents splashes generated when the pump body 1a and the discharge nipple 19 are joined by welding from intruding into the interior of the pump body 1a. Furthermore, the air in the space portion 91 that expands due to the heat generated during welding is released to the flow path 19a of the discharge nipple 19 or the flow path in the pump body 1a. If the air in the space portion 91 cannot be released to the flow path 19a of the discharge nipple 19 when it expands due to the temperature rise during welding, the pressure in the space portion 91 rises, and the pressure acts on the weld portion 90 from the inner side of the pump body 1a, whereby the welded joint length Lw may be shortened.

[0073] Therefore, for example, the upper limit of the minute gap C is set to 0.095 mm in order to prevent the intrusion of splashes of 0.1 mm or more that may cause a malfunction. In addition, for example, the lower limit of the minute gap C is set to 0.005 mm in order to reliably release the air expanded in the space 91 due to the temperature rise during welding to the flow path 19a of the discharge joint 19. That is, the prescribed range of the minute gap C is set to be greater than 0.005 mm and less than 0.095 mm.

[0074] In the conventional joint structure formed by welding the pump body and the discharge nipple, a contact portion is provided to make the inner circumference (side) of the mounting hole of the pump body contact the outer circumference of the discharge nipple in order to prevent splashes from entering the pump. Therefore, a space portion provided for the welding portion 90 cannot be formed at a position closer to the depth side of the mounting hole than the contact portion, and it is difficult to reduce the curvature of the inner circumference (recess) of the pump body forming the space portion.

[0075] In contrast, the space portion 91 of the present embodiment is formed in the range from the terminal end portion 90b of the weld portion 90 to the opposite surface 81 of the pump body 1a in the depth direction of the third mounting hole portion 1h, and is formed to be surrounded by the cylindrical outer peripheral surface 72 of the discharge joint 19 and the concave curved inner peripheral surface 82 of the pump body 1a. The space portion 91 is, for example, a shape similar to a semicircular meridian cross section obtained by cutting on a surface including the axis of the third mounting hole portion 1h. The roughly semicircular meridian cross section of the space portion 91 is formed by extending the meridian cross section to the opposite surface 81 of the pump body 1a compared to the existing joint structure, so that the curvature of the meridian cross section can be made smaller than that of the existing joint structure.

[0076] When high-pressure fuel flows through the pump body 1a and the discharge nipple 19, the pressure of the fuel generates a relatively greater stress than other parts at the concave curved inner circumferential surface 82 of the pump body 1a in the space 91 near the weld 90 of the discharge nipple 19. In the present embodiment, the space 91 is formed from the terminal 90b of the weld 90 to the range of the opposing surface 81 of the pump body 1a, thereby making it possible to reduce the curvature of the inner circumferential surface 82 forming the space 91 compared with the existing joint structure. Therefore, the stress generated on the inner circumferential surface 82 of the discharge nipple 19 can be reduced without changing the appearance shape and configuration of the high-pressure fuel supply pump 1, and the safety rate of the weld 90 is improved.

[0077] Next, use Figure 4 and Figure 5 A method for joining the discharge joint to the pump body will be described.

[0078] First, Figure 4 The end portion 70 of the discharge connector 19 shown is inserted into the third mounting hole 1h of the pump body 1a. Figure 5 The outer peripheral surface 72 of the discharge joint 19 shown is guided by sliding on the guide surface 86 of the pump body 1a. The flange portion 75 of the discharge joint 19 abuts against the outer surface 1e of the pump body 1a, thereby restricting the movement of the discharge joint 19 in the insertion direction. As a result, a small gap C of a size within a predetermined range is automatically formed by the opposing surface 81 of the pump body 1a and the end surface 71 of the discharge joint 19, and the inclined surface 73 of the discharge joint 19 is brought into abutment with the inclined surface 87 of the pump body 1a.

[0079] Next, the one end portion 70 of the discharge joint 19 is joined to the opening edge portion of the third mounting hole portion 1h of the pump body 1a by welding. Specifically, the welding laser is irradiated from the outer surface 1e side of the pump body 1a in a manner along the inclined surface 73 of the discharge joint 19 and the inclined surface 87 of the pump body 1a, and the one end portion 70 of the discharge joint 19 and the opening edge portion of the third mounting hole portion 1h are welded over the entire circumference. As a result, the gap between the one end portion 70 of the discharge joint 19 and the opening edge portion of the third mounting hole portion 1h of the pump body 1a is completely closed, thereby preventing leakage of high-pressure fuel.

[0080] In the welding process, Figure 5As shown in FIG. 1 , the weld 90 is formed so as to reach the space 91. As a result, the end portion (terminal end portion 90b) of the weld 90 on the space 91 side is continuous with the outer peripheral surface 72 of the discharge nipple 19 and the inner peripheral surface 82 of the pump body 1a, and constitutes a part of the wall surface of the space 91. At this time, the angle formed by the terminal end portion 90b of the weld 90 and the outer peripheral surface 72 of the discharge nipple 19, and the angle formed by the terminal end portion 90b of the weld 90 and the inner peripheral surface 82 of the pump body 1a are obtuse angles, so that the terminal end portion 90b can be prevented from becoming a shape that causes stress concentration.

[0081] The air in the space 91 expands due to the heat of welding, but the air is released into the flow path 19a of the discharge joint 19 or the inside of the pump body 1a through the small gap C. Therefore, the pressure in the space 91 does not rise excessively, and the welding length Lw can be prevented from being shorter than expected.

[0082] As described above, the high-pressure fuel supply pump 1 of the first embodiment of the present invention includes a pump body 1a having a third mounting hole 1h (hole) provided on the outer surface 1e, a discharge nipple 19 as a functional component mounted in the third mounting hole 1h (hole) of the pump body 1a, and a weld 90 for joining the pump body 1a and the discharge nipple (functional component) 19, and a space 91 is formed between the pump body 1a and the discharge nipple (functional component) 19 from the terminal end 90b of the weld 90 in the melting direction D toward the depth side of the third mounting hole 1h (hole) of the pump body 1a. The discharge nipple (functional component) 19 has an end face 71 in the depth direction of the third mounting hole 1h (hole), and an outer peripheral face 72 rising from the outer edge of the end face 71.

[0083] The wall surface of the third mounting hole portion 1h (hole portion) of the pump body 1a includes an opposing surface 81 that opposes the end surface 71 of the discharge nipple (functional component) 19, and an inner peripheral surface 82 that is located outside the outer peripheral surface 72 of the discharge nipple (functional component) 19 and reaches the terminal portion 90b of the weld 90 from the outer edge of the opposing surface 81. The end surface 71 of the discharge nipple (functional component) 19 and the opposing surface 81 of the pump body 1a form a small gap (gap) C of a size within a predetermined range. The space portion 91 is formed from the terminal portion 90b of the weld 90 to the opposing surface 81 of the pump body 1a. The entire inner peripheral surface 82 of the pump body 1a from the terminal portion 90b of the weld 90 to the opposing surface 81 is formed as a concave curved surface, constituting a part of the wall surface of the space portion 91.

[0084] According to this structure, the combination of the end surface 71 of the discharge joint 19 (functional component) and the opposing surface 81 of the pump body 1a opposing thereto can prevent splashes from intruding into the pump interior, so by extending the space portion 91 provided for the welded portion 90 to the opposing surface 81 of the pump body 1a, the curvature of the concave surface of the inner peripheral surface 82 of the pump body 1a forming the space portion 91 can be reduced. As a result, splashes can be prevented from intruding into the pump interior, and the stress generated on the inner peripheral surface 82 of the pump body 1a forming the space portion 91 can be reduced.

[0085] In addition, in the present embodiment, the contour curve obtained when the inner circumferential surface 82 of the pump body 1a is cut on a surface orthogonal to the direction along the inner circumferential surface 82 is composed of a first curved portion 83 having a first curvature radius and one end 83a of which is connected to the terminal portion 90b of the welding portion 90, and a second curved portion 84 having a second curvature radius smaller than the first curvature radius and one end 84a of which is connected to the other end 83b of the first curved portion 83 and the other end 84b of which is connected to the outer edge of the opposite surface 81.

[0086] According to this configuration, the first curved portion 83 located near the weld 90 has a larger curvature radius than the second curved portion 84 , and thus the stress generated in the vicinity of the weld 90 (the first curved portion 83 ) can be further reduced.

[0087] In addition, in the present embodiment, the contour curves 83 and 84 are constructed in such a manner that, in the portion surrounded by the contour curves 83 and 84, a first area S1 surrounded by a perpendicular line PL drawn from the other end 83b of the first curve portion 83 relative to a line segment LS connecting one end 83a of the first curve portion 83 and the other end 84b of the second curve portion 84 and the first curve portion 83 is larger than a second area S2 surrounded by the perpendicular line PL and the second curve portion 84.

[0088] According to this configuration, the area S1 formed by the first curved portion 83 located near the weld 90 is larger than the area S2 formed by the second curved portion 84 . This can further reduce the stress generated in the vicinity of the weld 90 (the first curved portion 83 ).

[0089] In addition, in the present embodiment, the contour curves 83 and 84 are formed in such a manner that a first length L1 in the depth direction of the third mounting hole portion 1h from one end 83a of the first curved portion 83 to the other end 83b is longer than a second length L2 in the depth direction of the hole portion 1h from one end 84a of the second curved portion 84 to the other end 84b.

[0090] According to this configuration, the length L1 of the first curved portion 83 located near the weld 90 is longer than the length L2 of the second curved portion 84 , so that the stress generated in the vicinity of the weld 90 (the first curved portion 83 ) can be further reduced.

[0091] In addition, in the present embodiment, the prescribed range of the small gap C (gap) is set to be greater than 0.005 mm and less than 0.095 mm. According to this structure, the small gap C (gap) can be used to prevent splashes of 0.1 mm or more, which may cause a malfunction, from intruding into the pump body 1a. In addition, the small gap C (gap) can also be used to reliably release the air in the space portion 91 that expands due to the temperature rise during welding into the flow path 19a of the discharge joint 19 and the pump body 1a.

[0092] In addition, the discharge nipple 19 (functional component) of the present embodiment has a flange portion 75 formed in a manner of protruding toward the outer peripheral side than the outer peripheral surface 72 and abutting against the outer surface 1e of the pump body 1a in the state of a single component before being joined to the pump body 1a. The flange portion 75 is configured so that when abutting against the outer surface 1e of the pump body 1a, the end surface 71 of the discharge nipple 19 (functional component) is arranged at a position where a small gap C (gap) is formed relative to the opposing surface 81 of the pump body 1a.

[0093] According to this structure, as long as the discharge connector 19 (functional component) is inserted into the third mounting hole portion 1h (hole portion) of the pump body 1a, a small gap C of a size within a specified range can be formed between the end face 71 of the discharge connector 19 (functional component) and the opposite face 81 of the pump body 1a, so that the discharge connector 19 (functional component) is easy to assemble to the pump body 1a.

[0094] [Second embodiment]

[0095] Next, a high pressure fuel supply pump according to a second embodiment of the present invention is used. Figure 6 Provide explanation. Figure 6 This is a cross-sectional view showing the joining structure of the discharge joint and the pump body in the high-pressure fuel supply pump according to the second embodiment of the present invention in an enlarged state. Figure 6 In, with Figure 1 to Figure 5 The same reference numerals as shown denote the same parts, and thus detailed description thereof will be omitted.

[0096] Figure 6 The high-pressure fuel supply pump 1A of the second embodiment of the present invention shown in FIG. 1 is different from the high-pressure fuel supply pump of the first embodiment (see FIG. 1A ). Figure 5) is that the shape of the portion where the discharge connector 19A and the pump body 1a are butted against each other is changed, and correspondingly to the change in the shape of the butted portion, the melting direction D of the welding portion 90 is changed to a direction along the insertion direction of the discharge connector 19A into the third mounting hole portion 1h (the axial direction of the third mounting hole portion 1h).

[0097] Specifically, the tapered inclined surface 73 (see reference 1 to the right) of the first embodiment, which exists in the state of a single component before being welded to the pump body 1a, is disposed at the one end portion 70A of the discharge joint 19A. Figure 5 ) portion is changed to a cylindrical butt joint surface 73A that is an extension of the outer peripheral surface 72. That is, one end side ( Figure 6 The left side in the figure) is connected to the outer peripheral surface 72, and the other end side ( Figure 6 The butt joint surface 73A is a portion that butts (opposes) a guide surface 86A described later of the pump body 1a and is a portion that melts during welding to form a welded portion 90.

[0098] In the pump body 1a, the cylindrical guide surface 86 and the tapered inclined surface 87 (see FIG. 1 ) of the first embodiment that exist before the discharge nipple 19A is welded are provided. Figure 5 ) is changed to a cylindrical guide surface 86A which is an extension of the guide surface 86 of the first embodiment. That is, the guide surface 86A is a cylindrical guide surface 86A on one end side ( Figure 6 The left side in the figure) is connected to the inner peripheral surface 82, and the other end side ( Figure 6 The guide surface 86A is a cylindrical surface connected to the outer surface 1e (right side in the figure). The guide surface 86A is a portion that guides the one end portion 70A of the discharge joint 19A and is butted (opposed) to the butt surface 73A of the discharge joint 19A. The guide surface 86A is a portion that melts together with a portion of the discharge joint 19A during welding to form the welded portion 90.

[0099] The welding portion 90 is formed by melting the pump body 1a and the discharge joint 19A by laser welding along the guide surface 86A of the pump body 1a and the butt surface 73A of the discharge joint 19A. Therefore, the melting direction D of the welding portion 90 is along the guide surface 86A of the pump body 1a and the butt surface 73A of the discharge joint 19A. That is, the melting direction D of the welding portion 90 is along the insertion direction of the discharge joint 19A into the third mounting hole portion 1h (the axial direction of the third mounting hole portion 1h). The welding portion 90 is formed from the outer surface of the flange portion 75 of the discharge joint 19A to the range of the space portion 91. A portion of the terminal portion 90b of the welding portion 90 constitutes a very small portion of the wall surface of the space portion 91.

[0100] In the present embodiment, the space portion 91 is also formed in the depth direction of the third mounting hole portion 1h, ranging from the terminal end portion 90b of the welding portion 90 to the opposite surface 81 of the pump body 1a, and is surrounded by the cylindrical outer peripheral surface 72 of the discharge connector 19A and the concave inner peripheral surface 82 of the pump body 1a.

[0101] The high-pressure fuel supply pump 1 of the second embodiment of the present invention prevents splashes from entering the pump interior by the combination of the end surface 71 of the discharge joint 19A (functional component) and the opposing surface 81 of the pump body 1a opposing thereto, and thus the curvature of the concave surface of the inner peripheral surface 82 of the pump body 1a forming the space 91 can be reduced by extending the space 91 provided for the weld 90 to the opposing surface 81 of the pump body 1a. Thus, splashes can be prevented from entering the pump interior, and stress generated on the inner peripheral surface 82 of the pump body 1a forming the space 91 can be reduced.

[0102] In addition, the present invention is not limited to the above-mentioned embodiments, and includes various modified examples. The above-mentioned embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not limited to all structures that must be described. A part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and the structure of other embodiments can be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0103] For example, the first and second embodiments described above show an example of applying the present invention to a structure in which the discharge joint 19, 19A as a functional component is joined to the pump body 1a. However, the present invention can also be applied to a structure in which the discharge valve mechanism 500 as a functional component is joined to the pump body 1a.

[0104] In addition, in the above-mentioned embodiment, the example in which the outer peripheral surface 72 of the discharge joint 19, 19A is formed into a cylindrical surface shape is shown, but it is also possible to Figure 5 and Figure 6 As shown by the two-dot chain line, the outer peripheral surface 72B of the discharge joint is formed by a concave curved surface. In this case, the space 91 is formed by being surrounded by the inner peripheral surface 82 of the concave curved surface of the pump body 1a and the outer peripheral surface 72B of the concave curved surface of the discharge joint.

[0105] In the above embodiment, an example is shown in which the contour curve obtained when the inner peripheral surface 82 of the pump body 1a is cut on a plane orthogonal to the annular direction along the inner peripheral surface 82 is formed by two curved portions, namely the first curved portion 83 and the second curved portion 84, having different curvature radii. However, the contour curve can also be formed by a single curve having a single curvature radius.

[0106] Furthermore, the contour curve may be constituted by three or more curved line portions having different curvature radii.

[0107] In the above embodiment, the size of the micro gap C is set to 0.005 mm or more and 0.095 mm or less. However, in order to give priority to preventing extremely small splashes from entering the pump body 1a, the size of the micro gap C can be smaller than 0.005 mm.

[0108] Description of Reference Numerals

[0109] 1, 1A... high-pressure fuel supply pump, 1a... pump body, 1e... outer peripheral surface (outer surface),

[0110] 1h…third mounting hole portion (hole portion), 3…pressurization chamber, 19, 19A…discharge connector (functional component), 71…end face, 72…outer peripheral surface, 75…flange portion, 81…end face, 82…inner peripheral surface, 83…first curved portion, 83a…one end, 83b…the other end, 84…second curved portion, 84a…one end, 84b…the other end, 90…welding portion, 90b…terminal portion, 91…space portion, C…small gap (gap), SL…line segment, PL…perpendicular line, S1…first area, S2…second area, L1…first length, L2…second length.

Claims

1. A high pressure fuel supply pump, characterized in that: include: A pump body having a hole portion disposed on an outer surface thereof; a functional component mounted on the hole portion of the pump body; and A welded portion joining the pump body and the functional component, A space is formed between the pump body and the functional component from the terminal end of the weld portion in the melting direction toward the depth side of the hole of the pump body. The functional components include: an end surface in the depth direction of the hole portion; and An outer peripheral surface rising from the outer edge of the end surface, The wall surface forming the hole portion of the pump body has: an opposing surface opposite to the end surface of the functional component; and an inner peripheral surface located outside the outer peripheral surface of the functional component and extending from the outer edge of the opposing surface to the terminal end of the welded portion, The end surface of the functional component and the facing surface of the pump body form a gap of a size within a predetermined range, The space portion is formed in a range from the terminal end of the weld portion to the opposing surface of the pump body. The inner peripheral surface of the pump body is formed entirely as a concave curved surface from the terminal end of the weld portion to the opposing surface, and constitutes a part of the wall surface of the space portion.

2. The high pressure fuel supply pump according to claim 1, characterized in that: The contour curve obtained when the inner peripheral surface of the pump body is cut at a plane perpendicular to a direction along the inner peripheral surface is composed of the following parts: A first curved portion having a first radius of curvature and one end side of which is connected to the terminal end of the weld portion; and A second curved portion has a second curvature radius smaller than the first curvature radius, one end of which is connected to the other end of the first curved portion and the other end of which is connected to the outer edge of the opposing surface.

3. The high pressure fuel supply pump according to claim 2, characterized in that: The contour curve is constructed so that, in a portion surrounded by the contour curve, a first area surrounded by a perpendicular line drawn from the other end of the first curve portion relative to a line segment connecting one end of the first curve portion with the other end of the second curve portion and the first curve portion is larger than a second area surrounded by the perpendicular line and the second curve portion.

4. The high pressure fuel supply pump according to claim 2, characterized in that: The contour curve is configured such that a first length in the depth direction of the hole from the one end to the other end of the first curve portion is longer than a second length in the depth direction of the hole from the one end to the other end of the second curve portion.

5. The high pressure fuel supply pump according to claim 1, characterized in that: The predetermined range of the gap is set to be not less than 0.005 mm and not more than 0.095 mm.

6. The high pressure fuel supply pump according to claim 1, characterized in that: The functional component, in a state of a single component before being joined to the pump body, has a flange portion formed so as to protrude toward the outer peripheral side from the outer peripheral surface and abut against the outer surface of the pump body. The flange portion is configured such that, when the flange portion abuts against the outer surface of the pump body, the end surface of the functional component is disposed at a position where the gap is formed with respect to the opposing surface of the pump body.

7. The high pressure fuel supply pump according to claim 1, characterized in that: The functional component is a discharge nipple for discharging pressurized fuel.

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