Fuel pump

Abstract

A fuel pump according to the present invention is provided with an electromagnetic suction valve having a coil winding part in which an electromagnetic coil is wound around a bobbin, and a magnetic circuit structure part that constitutes a magnetic circuit when a current flows through the coil. The magnetic circuit structure portion has a yoke disposed so as to surround the coil winding portion, and a predetermined portion facing the coil winding portion via a gap in the radial direction of the electromagnetic suction valve. The size of the gap is set such that the coil winding portion and the predetermined portion come into contact first when an impact force from the outside toward the inside in the radial direction of the electromagnetic suction valve is applied to the yoke or the coil winding portion.

Description

Technical Field

[0001] The present invention relates to a fuel pump. Background Art

[0002] Fuel pumps are widely used in internal combustion engines (engines) such as automobiles, and the fuel pumps include an electromagnetic suction valve that sets fuel to high pressure and discharges fuel at a desired flow rate (for example, see Patent Document 1). The fuel pump described in Patent Document 1 includes a pump body, a cylinder that forms a pressurized chamber, a plunger that is freely slidably held by the cylinder, and a discharge valve mechanism in addition to a suction valve portion, a magnetic circuit structure portion, and a coil winding portion that constitute the electromagnetic suction valve.

[0003] When the engine is equipped with a fuel pump, a part of the electromagnetic suction valve, namely the magnetic circuit structure and the coil winding part, is arranged in a state of protruding outward from the pump body. Therefore, in the event of a traffic accident accompanied by a collision of a car, for example, an impact force (impact load) is applied to the solenoid mechanism and the coil part. The magnitude of the impact force is pre-assumed through collision tests, simulations, etc., and the dimensions of each part of the fuel pump are set based on this assumption. Prior art literature Patent Literature

[0004] Patent Document 1: International Publication No. 2018 / 221158 Summary of the invention Technical problem to be solved by the invention

[0005] However, in order to realize a fuel pump with higher safety, it is desirable to devise a structure in advance so that even when an impact force exceeding an expected magnitude is applied to the yoke and the like, structural components of the electromagnetic suction valve are not damaged.

[0006] An object of the present invention is to provide a fuel pump capable of effectively suppressing damage to components of an electromagnetic suction valve even when an impact force is applied to a coil winding portion and a magnetic circuit structure portion constituting the electromagnetic suction valve. Technical means for solving technical problems

[0007] In order to solve the above-mentioned problems, for example, the structure described in the claims is adopted. The present application includes a plurality of methods for solving the above-mentioned problems. If one of them is cited, it is a fuel pump including an electromagnetic suction valve, wherein the electromagnetic suction valve has a coil winding portion formed by winding an electromagnetic coil on a wire tube, and a magnetic circuit structure portion that forms a magnetic circuit when current flows through the electromagnetic coil. The magnetic circuit structure portion has a yoke configured to surround the coil winding portion, and a specified portion opposite to the coil winding portion via a gap in the radial direction of the electromagnetic suction valve. The size of the gap is set so that when an impact force is applied to the yoke or the coil winding portion from the radial outside toward the inside of the electromagnetic suction valve, the coil winding portion and the specified portion come into contact first. Effects of the Invention

[0008] According to the present invention, even when an impact force is applied to a coil winding portion or a magnetic circuit structure portion constituting an electromagnetic suction valve, damage to the structural components of the electromagnetic suction valve can be effectively suppressed. Problems, structures, and effects other than those described above will become more apparent from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 1 is an overall configuration diagram of a fuel supply system using the fuel pump according to the present embodiment. Figure 2 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at position II-II. Figure 3 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at position III-III. Figure 4 This is a transverse cross-sectional view of the high-pressure fuel supply pump taken parallel to the horizontal plane. Figure 5 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at the VV position. Figure 6 It is a longitudinal sectional view for explaining the structure of an electromagnetic suction valve according to a comparative embodiment. Figure 7 It is a longitudinal sectional view for explaining the structure of the electromagnetic suction valve according to the embodiment. DETAILED DESCRIPTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the accompanying drawings, elements having substantially the same function or structure are denoted by the same reference numerals to omit repeated description.

[0011] [Fuel supply system] Figure 1 1 is an overall configuration diagram of a fuel supply system using the fuel pump according to the present embodiment. like Figure 1 As shown, the fuel supply system includes a high-pressure fuel supply pump 100 as a fuel pump, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and a plurality of injectors 107. Components of the high-pressure fuel supply pump 100 are integrally assembled to a pump body 1.

[0012] Fuel is stored in a fuel tank 103. The fuel in the fuel tank 103 is drawn by a feed pump 102. The feed pump 102 is driven based on a signal sent to the feed pump 102 from the ECU 101, thereby drawing fuel. The fuel drawn by the feed pump 102 is pressurized to an appropriate pressure by a pressure regulator (not shown), and is sent to the low-pressure fuel suction port 51 of the high-pressure fuel supply pump 100 through the low-pressure pipe 104.

[0013] The high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 by the driving of the feed pump 102, and pressure-feeds it to the common rail 106. To the common rail 106, a fuel pressure sensor 105 and a plurality of injectors 107 are mounted.

[0014] The fuel pressure sensor 105 detects the pressure of the fuel and outputs the detected pressure data to the ECU 101. The ECU 101 calculates the appropriate amount of injected fuel (target injection fuel length), the appropriate fuel pressure (target fuel pressure), etc. based on the engine state quantities (e.g., crank angle, throttle opening, engine speed, fuel pressure, etc.) obtained from various sensors.

[0015] A plurality of injectors 107 are installed to match the number of cylinders (combustion chambers), and inject fuel according to a drive current output from ECU 101. The fuel supply system of this embodiment is a so-called direct injection engine system in which injectors 107 inject fuel directly into cylinders of the engine.

[0016] The ECU 101 controls the driving of the high-pressure fuel supply pump 100 and the plurality of injectors 107 based on the calculation results of the fuel pressure (target fuel pressure) etc. That is, the ECU 101 has the function of a pump control unit for controlling the high-pressure fuel supply pump 100 and the function of an injector control unit for controlling the injectors 107.

[0017] The high-pressure fuel supply pump 100 includes a pressure pulsation reduction mechanism 9, an electromagnetic suction valve 3 as a capacity variable mechanism, and a relief valve 4 ( Figure 2 ) and the discharge valve 8. The fuel flowing in from the low-pressure fuel suction port 51 reaches the suction port 31b of the electromagnetic suction valve 3 through the pressure pulsation reduction mechanism 9 and the suction passage 10b.

[0018] The fuel flowing into the electromagnetic suction valve 3 passes through the valve portion 32, and then flows into the pressure chamber 11 through the suction passage 1d formed in the pump body 1. The plunger 2 is inserted into the pressure chamber 11 so as to be reciprocating. The plunger 2 is moved by the cam 91 ( Figure 2 ) to transmit power and reciprocate.

[0019] In the pressurizing chamber 11, fuel is sucked from the electromagnetic suction valve 3 during the descending stroke of the plunger 2, and the fuel is pressurized during the ascending stroke. If the fuel pressure in the pressurizing chamber 11 exceeds a predetermined value due to the pressurization, the discharge valve 8 opens. As a result, the high-pressure fuel is sent to the common rail 106 through the discharge passage 12a. The fuel discharge of the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve 3. Moreover, the opening and closing of the electromagnetic suction valve 3 is controlled by the ECU 101.

[0020] [High-pressure fuel supply pump] Figure 2 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at position II-II. Figure 3 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at the III-III I position. Figure 4 This is a transverse cross-sectional view of the high-pressure fuel supply pump taken parallel to the horizontal plane. Figure 5 is Figure 4 A longitudinal sectional view of the high-pressure fuel supply pump is taken at the VV position.

[0021] like Figure 2 to Figure 5 As shown, the pump body 1 of the high pressure fuel supply pump 100 is formed in a substantially cylindrical shape. Figure 2 and Figure 3 As shown, the pump body 1 is provided with a first chamber 1a, a second chamber 1b, a third chamber 1c and a suction passage 1d ( Figure 2 The pump body 1 is in close contact with the fuel pump mounting portion 90 and is fixed to the fuel pump mounting portion 90 by a plurality of bolts or screws (not shown). The fuel pump mounting portion 90 is a portion where the high-pressure fuel supply pump 100 is mounted.

[0022] The first chamber 1a is a cylindrical space portion provided in the pump body 1. The center line 1A of the first chamber 1a coincides with the center line of the pump body 1. One end of the plunger 2 is inserted into the first chamber 1a. The plunger 2 reciprocates in the first chamber 1a. The first chamber 1a and one end of the plunger 2 form a pressurized chamber 11.

[0023] The second chamber 1b is a cylindrical space provided in the pump body 1. The diameter of the second chamber 1b is smaller than that of the first chamber 1a. The center line (not shown) of the second chamber 1b is perpendicular to the center line 1A of the first chamber 1a. The relief valve 4 is disposed in the second chamber 1b.

[0024] The first chamber 1a and the second chamber 1b are connected through a circular connecting hole 1e. The diameter of the connecting hole 1e is the same as that of the first chamber 1a. The connecting hole 1e is located at one end of the first chamber 1a. The diameter of the connecting hole 1e is larger than the outer diameter of the plunger 2. The center line 1A of the first chamber 1a passing through the center of the connecting hole 1e is orthogonal to the center line of the second chamber 1b.

[0025] like Figure 3 and Figure 5 As shown, the diameter of the connecting hole 1e is larger than the diameter of the second chamber 1b. The connecting hole 1e has a tapered surface 1f. In the cross section perpendicular to the center line of the second chamber 1b, the diameter of the tapered surface 1f gradually decreases toward the second chamber 1b. As a result, the fuel passing through the relief valve 4 can smoothly return to the pressurizing chamber 11 along the tapered surface 1f.

[0026] The third chamber 1c is a cylindrical space portion provided in the pump body 1. The third chamber 1c is continuous with the other end of the first chamber 1a. The center line of the third chamber 1c coincides with the center line 1A of the first chamber 1a and the center line of the pump body 1. The diameter of the third chamber 1c is larger than the diameter of the first chamber 1a. The third chamber 1c is provided with a cylinder 6 for guiding the reciprocating motion of the plunger 2.

[0027] The cylinder 6 is formed in a cylindrical shape. The cylinder 6 is pressed into the third chamber 1c of the pump body 1 in the pressing portion 6a. One end of the cylinder 6 abuts against the top surface of the third chamber 1c. The top surface of the third chamber 1c is located at the step portion between the first chamber 1a and the third chamber 1c. In the cylinder 6, only the pressing portion 6a becomes the pressing dimension, and the cylinder diameter closer to the pressurized chamber 11 than the pressing portion 6a is set to be smaller than the diameter of the third chamber 1c. Therefore, there is a gap between the outer peripheral surface of the cylinder 6 and the inner peripheral surface of the third chamber 1c on the side closer to the pressurized chamber 11 than the pressing portion 6a. The plunger 2 is slidably in contact with the inner peripheral surface of the cylinder 6.

[0028] On the other hand, an O-ring 93 as a seat member is mounted on the fitting portion between the fuel pump mounting portion 90 and the pump body 1. The O-ring 93 prevents the engine oil from leaking to the outside of the engine (internal combustion engine) through between the fuel pump mounting portion 90 and the pump body 1.

[0029] The tappet 92 is arranged at the lower end of the plunger 2. The tappet 92 converts the rotational motion of the cam 91 mounted on the camshaft of the engine into an up-and-down motion, thereby raising and lowering the plunger 2. The plunger 2 receives the force of the spring 16 via the retainer 15, and is urged toward the cam 91 by the spring force. The lower end of the plunger 2 is pressed against the tappet 92 by the force of the spring 16. The tappet 92 reciprocates as the cam 91 rotates. The plunger 2 and the tappet 92 are integrally connected at Figure 5 The pressure chamber 11 reciprocates (rises and falls) in the up and down directions, thereby changing the volume of the pressure chamber 11.

[0030] The seal holder 17 is arranged between the cylinder 6 and the retainer 15. The seal holder 17 is formed in a cylindrical shape, and the plunger 2 is inserted into the cylindrical portion. The seal holder 17 forms a sub-chamber 17a. The seal holder 17 retains the plunger seal 18 at the lower end portion on the retainer 15 side. The sub-chamber 17a is arranged on the cylinder 6 side relative to the plunger seal 18. The sub-chamber 17a is formed from the periphery of the small diameter portion 2b of the plunger 2 to the periphery of the small diameter portion of the cylinder 6.

[0031] The plunger seal 18 is slidably in contact with the outer peripheral surface of the small diameter portion 2b of the plunger 2. When the plunger 2 reciprocates, the plunger seal 18 seals the fuel in the sub-chamber 17a so that the fuel in the sub-chamber 17a does not flow into the engine. In addition, the plunger seal 18 prevents the lubricating oil (including the engine oil) that lubricates the sliding parts in the engine from flowing into the pump body 1.

[0032] exist Figure 2 In the embodiment, the plunger 2 reciprocates in the up-down direction. If the plunger 2 descends, the volume of the pressurized chamber 11 increases, and if the plunger 2 ascends, the volume of the pressurized chamber 11 decreases. In other words, the plunger 2 is configured to reciprocate in the direction of increasing and decreasing the volume of the pressurized chamber 11.

[0033] The plunger 2 has a large diameter portion 2a and a small diameter portion 2b. The boundary portion between the large diameter portion 2a and the small diameter portion 2b has a stepped structure. When the plunger 2 reciprocates, the stepped portion between the large diameter portion 2a and the small diameter portion 2b moves in the auxiliary chamber 17a. Therefore, the volume of the auxiliary chamber 17a increases or decreases by the reciprocating motion of the plunger 2.

[0034] The auxiliary chamber 17a is connected to the fuel passage 10c ( Figure 3 , Figure 5 ) is connected to the low-pressure fuel chamber 10. When the plunger 2 descends, a fuel flow is generated from the sub-chamber 17a to the low-pressure fuel chamber 10, and when the plunger 2 rises, a fuel flow is generated from the low-pressure fuel chamber 10 to the sub-chamber 17a. As a result, the fuel flow rate to the inside and outside of the pump during the suction stroke or return stroke of the high-pressure fuel supply pump 100 can be reduced, and the pressure pulsation generated inside the high-pressure fuel supply pump 100 can be reduced.

[0035] like Figure 3 As shown, a low-pressure fuel chamber 10 is provided at the upper portion of the pump body 1. In addition, a suction joint 5 is mounted on the side portion of the pump body 1. The suction joint 5 is connected to the low-pressure piping 104 ( Figure 1 The low pressure pipe 104 is for supplying the fuel from the fuel tank 103 ( Figure 1 ) The fuel provided by the pump body 1 passes through the pipe. The fuel in the fuel tank 103 is supplied to the inside of the pump body 1 through the suction joint 5.

[0036] The suction joint 5 has a low-pressure fuel suction port 51 connected to the low-pressure pipe 104 and a suction flow path 52 communicating with the low-pressure fuel suction port 51. The fuel passing through the suction flow path 52 is supplied to the low-pressure fuel chamber 10 through a suction filter 53. The suction filter 53 is provided inside the pump body 1. The suction filter 53 removes foreign matter present in the fuel and prevents the foreign matter from entering the high-pressure fuel supply pump 100.

[0037] The low-pressure fuel chamber 10 is provided with a low-pressure fuel flow path 10a and an intake path 10b ( Figure 2 The low-pressure fuel flow path 10a is provided with a pressure pulsation reduction mechanism 9. If the fuel flowing into the pressurizing chamber 11 returns to the suction passage 10b again through the electromagnetic suction valve 3 in the valve open state, pressure pulsation is generated in the low-pressure fuel chamber 10. The pressure pulsation reduction mechanism 9 reduces the pressure pulsation generated in the high-pressure fuel supply pump 100 from affecting the low-pressure piping 104.

[0038] The pressure pulsation reduction mechanism 9 is constituted by, for example, a metal diaphragm damper. The metal diaphragm damper has a structure in which two disc-shaped metal plates in a corrugated plate shape are attached to the outer circumference of each disc-shaped metal plate, and an inert gas such as argon is injected into the space formed between the two disc-shaped metal plates. The metal diaphragm damper absorbs or reduces pressure pulsation by the expansion and contraction of the space formed between the two disc-shaped metal plates.

[0039] The suction passage 10b is connected to the suction port 31b ( Figure 2 The fuel passing through the low-pressure fuel flow path 10a reaches the suction port 31b of the electromagnetic suction valve 3 through the suction passage 10b.

[0040] [Solenoid suction valve] Next, the structure and operation of the electromagnetic suction valve included in the high-pressure fuel supply pump according to the present embodiment will be described. like Figure 2 and Figure 4 As shown, the electromagnetic suction valve 3 is inserted into the horizontal hole formed in the pump body 1. The electromagnetic suction valve 3 has a suction valve seat 31, a valve portion 32, a rod 33, a rod urging spring 34, an electromagnetic coil 35, an armature 36, a stopper 37, a valve urging spring 38, and an armature urging spring 36a.

[0041] The suction valve seat 31 is pressed into the horizontal hole of the pump body 1. The suction valve seat 31 is formed in a cylindrical shape. The inner peripheral portion of the suction valve seat 31 is provided with a seating portion 31a. In addition, the suction valve seat 31 is formed with a suction port 31b. The suction port 31b is formed to reach the inner peripheral portion from the outer peripheral portion of the suction valve seat 31. The suction port 31b is connected to the suction passage 10b in the low-pressure fuel chamber 10.

[0042] A stopper 37 is disposed in the horizontal hole of the pump body 1. The stopper 37 is disposed in a state opposite to the seat portion 31a of the suction valve seat 31 in the central axis direction of the rod 33. The valve portion 32 is disposed between the stopper 37 and the seat portion 31a. The valve urging spring 38 is disposed between the stopper 37 and the valve portion 32. The valve urging spring 38 urges the valve portion 32 toward the seat portion 31a.

[0043] The valve portion 32 abuts against the seat portion 31a, thereby closing the communication portion between the suction port 31b and the pressurized chamber 11. Thus, the electromagnetic suction valve 3 is in a closed valve state. In addition, the valve portion 32 abuts against the stopper 37, thereby opening the communication portion between the suction port 31b and the pressurized chamber 11. Thus, the electromagnetic suction valve 3 is in an open valve state.

[0044] The rod 33 passes through a cylindrical hole formed in the suction valve seat 31. One end of the rod 33 abuts against the valve portion 32. The rod urging spring 34 urges the valve portion 32 via the rod 33 on the side of the stopper 37, that is, in the direction of opening the electromagnetic suction valve 3. One end of the rod urging spring 34 engages with a flange portion 33a formed on the other end side of the rod 33. The other end of the rod urging spring 34 engages with a magnetic core 39. The magnetic core 39 is arranged to surround the rod urging spring 34.

[0045] The armature 36 is arranged in a state opposite to the end face of the magnetic core 39. In addition, the armature 36 is engaged with the flange portion 33a of the rod 33 on the side opposite to one end of the above-mentioned rod urging member 34. The armature urging spring 36a applies force to press the armature 36 to the flange portion 33a of the rod 33. The electromagnetic coil 35 is arranged to surround the magnetic core 39. The electromagnetic coil 35 is electrically connected to the terminal member 40. The terminal member 40 is a member for allowing current to flow through the electromagnetic coil 35. The terminal member 40 is provided on the connector 46.

[0046] When the current does not flow through the electromagnetic coil 35, that is, in the non-energized state, the rod 33 is forced in the valve opening direction by the rod force spring 34, pressing the valve portion 32 in the valve opening direction. Therefore, the valve portion 32 leaves the seat portion 31a and abuts against the stopper 37, and the electromagnetic suction valve 3 is in the valve opening state. In other words, the electromagnetic suction valve 3 becomes a normally open electromagnetic valve that opens in the non-energized state.

[0047] When the electromagnetic suction valve 3 is in the open state, the fuel in the suction port 31b flows through the gap between the valve portion 32 and the seat portion 31a, and then flows into the pressurized chamber 11 through the multiple fuel passage holes (not shown) of the stopper 37 and the suction passage 1d. When the electromagnetic suction valve 3 is in the open state, the valve portion 32 contacts the stopper 37, so the position of the valve portion 32 in the valve opening direction is restricted. At this time, the gap between the valve portion 32 and the seat portion 31a is within the movable range of the valve portion 32, and this movable range becomes the valve opening stroke.

[0048] In contrast, when current flows through the electromagnetic coil 35 in the non-energized state, magnetic flux is generated inside the armature 36, the fixed core 304, the first yoke portion 301, the second yoke portion 302, and the magnetic core 39. As a result, a magnetic attraction force is generated between the magnetic core 39 and the armature 36, and the armature 36 is attracted to the direction close to the magnetic core 39, that is, the valve closing direction by the magnetic attraction force. As a result, the armature 36 moves against the force of the rod urging spring 34 and contacts the end surface of the magnetic core 39. When the armature 36 moves in the valve closing direction in this way, the rod 33 moves together with the armature 36. Therefore, the valve portion 32 is released from the force in the valve opening direction and moves in the valve closing direction by the force of the valve urging spring 38. Then, when the valve portion 32 contacts the seat portion 31a of the suction valve seat 31, the electromagnetic suction valve 3 is in the valve closing state.

[0049] [Discharge valve] Next, the structure and operation of the discharge valve included in the high-pressure fuel supply pump according to the present embodiment will be described. like Figure 4 and Figure 5 As shown, the discharge valve 8 is connected to the outlet side (downstream side) of the pressurizing chamber 11. The discharge valve 8 includes a discharge valve seat 81 communicating with the pressurizing chamber 11, a valve portion 82 contacting and separating from the discharge valve seat 81, a discharge valve spring 83 urging the valve portion 82 toward the discharge valve seat 81, a discharge valve stopper 84 determining the stroke (movement distance) of the valve portion 82, and a plunger 85 for cutting off fuel leakage to the outside.

[0050] The discharge valve stopper 84 is pressed into the plunger 85. The plunger 85 is joined to the pump body 1 by welding at the welding portion 86. The discharge valve 8 communicates with the discharge valve chamber 87. The discharge valve chamber 87 is opened and closed by the valve portion 82. The discharge valve chamber 87 is formed in the pump body 1.

[0051] The pump body 1 is provided with a second chamber 1b ( Figure 2 ) is connected to the horizontal hole, and the discharge joint 12 is inserted into the horizontal hole. The discharge joint 12 is connected to the horizontal hole by the welding part 12c ( Figure 4 ) is fixed to the pump body 1 by welding. The discharge joint 12 has a discharge passage 12a and a fuel discharge port 12b. The discharge passage 12a is connected to the horizontal hole of the pump body 1 and the discharge valve chamber 87. The fuel discharge port 12b is formed at one end of the discharge passage 12a. The discharge passage 12a is connected to the common rail 106 ( Figure 1 ) connected.

[0052] In the discharge valve 8 having the above-described structure, when there is no fuel pressure difference (fuel pressure difference) between the pressurizing chamber 11 and the discharge valve chamber 87, the valve portion 82 is pressed against the discharge valve seat 81 by the force of the discharge valve spring 83. Therefore, the discharge valve 8 is in a closed state. On the other hand, when the fuel pressure in the pressurizing chamber 11 is higher than the fuel pressure in the discharge valve chamber 87, the valve portion 82 moves toward the discharge valve stopper 84 against the force of the discharge valve spring 83. As a result, the discharge valve 8 is in an open state.

[0053] When the discharge valve 8 is in the closed state, the high-pressure fuel in the pressurizing chamber 11 passes through the discharge valve 8 and reaches the discharge valve chamber 87. The fuel reaching the discharge valve chamber 87 is discharged to the common rail 106 ( ) through the discharge passage 12a of the discharge joint 12 and the fuel discharge port 12b. Figure 1 ). The discharge valve 8 functions as a check valve that restricts the direction in which the fuel flows due to the above-described structure and operation.

[0054] [Relief valve] Figure 2 The relief valve 4 shown is configured to operate when a problem occurs in the common rail 106 or a member in front of it and the common rail 106 becomes high pressure exceeding a predetermined predetermined pressure, and to return the fuel in the discharge passage 12a to the pressurizing chamber 11. The relief valve 4 is arranged in the direction of reciprocation of the plunger 2 (up and down direction) and is arranged at a position higher than the discharge valve 8 ( Figure 5 ) higher position.

[0055] The relief valve 4 includes a relief spring 41, a relief valve bracket 42, a valve portion 43, and a seat member 44. The relief valve 4 is inserted from the horizontal hole of the pump body 1 into which the discharge joint 12 is inserted, and is arranged in the second chamber 1b. One end of the relief spring 41 abuts against one end of the second chamber 1b formed in the pump body 1. The other end of the relief spring 41 abuts against the flange portion of the relief valve bracket 42. The relief valve bracket 42 is engaged with the valve portion 43. The force of the relief spring 41 is applied to the valve portion 43 via the flange portion of the relief valve bracket 42.

[0056] The valve portion 43 is pressed against the seat member 44 by the urging force of the relief spring 41. As a result, the fuel passage is blocked by the valve portion 43 and the seat member 44. Therefore, the relief valve 4 is in a closed valve state. The movement direction of the relief valve holder 42 and the valve portion 43 is orthogonal to the direction of the reciprocating motion of the plunger 2. The center line of the relief valve holder 42 in the relief valve 4 is orthogonal to the center line of the plunger 2.

[0057] The seat member 44 forms a fuel passage at a portion opposite to the valve portion 43. The seat member 44 is formed in a cylindrical shape. The internal space of the seat member 44 communicates with the fuel passage. In addition, the internal space of the seat member 44 communicates with the discharge passage 12a on the side opposite to the valve portion 43. The movement of the fuel between the upstream side of the pressurizing chamber 11 and the downstream side of the seat member 44 is cut off by the valve portion 43 and the seat member 44 contacting (closely contacting) and blocking the fuel passage.

[0058] When the pressure in the common rail 106 or its front member increases, the fuel in the seat member 44 resists the force of the relief spring 41 and presses the valve portion 43. As a result, the valve portion 43 moves in a direction away from the seat member 44. As a result, the relief valve 4 is in an open state. When the relief valve 4 is in an open state, the fuel in the discharge passage 12a returns to the pressurizing chamber 11 through the fuel passage formed between the valve portion 43 and the seat member 44. Therefore, the pressure for opening the relief valve 4 is determined by the force of the relief spring 41.

[0059] The moving direction of the valve portion 43 in the relief valve 4 is different from the moving direction of the valve portion 82 in the discharge valve 8. Specifically, the moving direction of the valve portion 82 in the discharge valve 8 is the first radial direction of the pump body 1, and the moving direction of the valve portion 43 in the relief valve 4 is the second radial direction different from the first radial direction of the pump body 1. Thus, the discharge valve 8 and the relief valve 4 can be arranged at positions that do not overlap each other in the up-down direction, the space inside the pump body 1 can be effectively utilized, and the pump body 1 can be miniaturized.

[0060] [Operation of the high-pressure fuel supply pump] Next, use Figure 2 and Figure 4 The operation of the high-pressure fuel supply pump according to the present embodiment will be described. Figure 2 The state where the plunger 2 rises to the top dead center is shown. When plunger 2 is Figure 2 When the state shown is lowered, if the electromagnetic suction valve 3 is in the open state, the fuel flows from the suction passage 1d into the pressurizing chamber 11. Hereinafter, the stroke of the plunger 2 descending is referred to as the suction stroke. On the other hand, when the plunger 2 rises from the bottom dead center, if the electromagnetic suction valve 3 is in the closed state, the fuel in the pressurizing chamber 11 is pressed by the plunger 2 and the pressure is increased. The pressurized fuel is pressed to the common rail 106 ( Figure 1 ) Hereinafter, the process of the plunger 2 rising is referred to as a rising stroke.

[0061] As described above, when the electromagnetic suction valve 3 is closed during the ascending stroke, the fuel sucked into the pressurizing chamber 11 during the suction stroke one cycle ago is pressurized. At this time, the pressurized fuel is discharged to the common rail 106 side. On the other hand, when the electromagnetic suction valve 3 is opened during the ascending stroke, the fuel in the pressurizing chamber 11 is pressed back to the suction passage 1d side and is not discharged to the common rail 106 side. Thus, the fuel discharge of the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve 3. Moreover, the opening and closing of the electromagnetic suction valve 3 is controlled by the ECU 101.

[0062] During the suction stroke, the volume of the pressurizing chamber 11 increases, and the fuel pressure in the pressurizing chamber 11 decreases. As a result, the fluid pressure difference between the suction port 31b and the pressurizing chamber 11 (hereinafter referred to as "the fluid pressure difference before and after the valve portion 32") becomes smaller. Then, if the force of the rod biasing spring 34 is greater than the fluid pressure difference before and after the valve portion 32, the rod 33 moves in the valve opening direction, the valve portion 32 separates from the seat portion 31a of the suction valve seat 31, and the electromagnetic suction valve 3 becomes an open valve state.

[0063] After the suction stroke is completed, it is transferred to the rising stroke. At this time, the electromagnetic coil 35 maintains a non-energized state. Therefore, no magnetic attraction is generated between the armature 36 and the magnetic core 39. In this state, a pressing force in the valve opening direction and a pressing force in the valve closing direction act on the valve portion 32. The pressing force in the valve opening direction acting on the valve portion 32 is a pressing force corresponding to the difference between the force of the rod force spring 34 and the force of the valve force spring 38. The pressing force in the valve closing direction acting on the valve portion 32 is a pressing force caused by the fluid force generated when the fuel flows back from the pressurized chamber 11 to the low-pressure fuel flow path 10a.

[0064] In this state, in order to keep the electromagnetic suction valve 3 in the open state, the difference between the force of the rod biasing spring 34 and the force of the valve biasing spring 38 is set to be larger than the above-mentioned fluid force. The volume of the pressurizing chamber 11 decreases as the plunger 2 rises. Therefore, the fuel sucked into the pressurizing chamber 11 passes again between the valve portion 32 and the seat portion 31a and returns to the suction port 31b. As a result, the pressure in the pressurizing chamber 11 does not rise. This stroke is called a return stroke.

[0065] During the return trip, if ECU101( Figure 1) provides a control signal to the electromagnetic suction valve 3, and the current flows to the electromagnetic coil 35 via the terminal member 40. When the current flows through the electromagnetic coil 35, a magnetic flux is generated around the electromagnetic coil 35. The magnetic flux is mainly generated inside the armature 36, the fixed core 304, the first yoke part 301, the second yoke part 302 and the magnetic core, which are magnetic materials. As a result, a magnetic attraction force is generated between the magnetic core 39 and the armature 39. Therefore, the armature 36 is attracted to the magnetic core 39. At this time, the rod 33 resists the force of the rod force spring 34 and moves in the valve closing direction together with the armature 36.

[0066] When the rod 33 and the armature 36 move in the valve closing direction in this way, the valve portion 32 is released from the force in the valve opening direction. Therefore, the valve portion 32 moves in the valve closing direction by the force of the valve biasing spring 38 and the fluid force generated by the fuel flowing into the suction passage 10b. Then, when the valve portion 32 contacts (sits on) the seat portion 31a of the suction valve seat 31, the electromagnetic suction valve 3 is in the valve closing state.

[0067] After the electromagnetic suction valve 3 is closed, the fuel in the pressurizing chamber 11 is pressurized as the plunger 2 rises. When the fuel pressure reaches a predetermined pressure or above, the fuel is discharged to the common rail 106 ( Figure 1 ). This stroke is called the discharge stroke. The stroke of the plunger 2 moving from the bottom dead center to the top dead center, i.e., the ascending stroke, is composed of a return stroke and a discharge stroke. The ECU 101 can control the timing of energizing the electromagnetic coil 35 of the electromagnetic suction valve 3, thereby controlling the amount of fuel (high-pressure fuel) discharged to the common rail 106.

[0068] Specifically, if the timing of energizing the electromagnetic coil 35 is made earlier, the proportion of the return stroke in the ascending stroke becomes smaller and the proportion of the discharge stroke becomes larger. Therefore, the fuel returned to the intake passage 10b becomes less, and the fuel discharged to the common rail 106 becomes more. On the other hand, if the timing of energizing the electromagnetic coil 35 is made later, the proportion of the return stroke in the ascending stroke becomes larger and the proportion of the discharge stroke becomes smaller. Therefore, the fuel returned to the intake passage 10b becomes more, and the fuel discharged to the common rail 106 becomes less. Therefore, the ECU 101 can control the timing of energizing the electromagnetic coil 35, thereby controlling the amount of fuel discharged to the common rail 106 according to the amount required by the engine (internal combustion engine).

[0069] [Solenoid suction valve] Figure 6 1 is a longitudinal cross-sectional view for explaining the structure of an electromagnetic suction valve according to a comparative embodiment. The comparative embodiment has a common structure with the present embodiment except for a part of the structure. Figure 6In the embodiment, the coil winding portion 60 includes the electromagnetic coil 35 and a bobbin 305. The electromagnetic coil 35 is wound around the resin bobbin 305 by aligned winding. The bobbin 305 is arranged inside the first yoke portion 301 in a fixed state.

[0070] The magnetic circuit structure portion 70 constitutes a magnetic circuit for allowing magnetic flux to pass when current flows through the electromagnetic coil 35. The magnetic circuit structure portion 70 is composed of an armature 36, a fixed core 304, a first yoke portion 301, a second yoke portion 302, and a magnetic core 39. The first yoke portion 301 and the second yoke portion 302 are elements that constitute a yoke. In the present embodiment, as an example, the first yoke portion 301 and the second yoke portion 302 are separated, but they may also be integrated. The components that constitute the magnetic circuit structure portion 70 are made of magnetic material.

[0071] The first yoke portion 301 is configured to surround the coil winding portion 60. The first yoke portion 301 is pressed and fixed to the fixed core 304 by the press-in portion 311. The second yoke portion 302 is pressed to the magnetic core 39 by the force of the yoke force spring 310. The yoke force spring 310 is arranged between the second yoke portion 302 and the spring stopper 306 in the central axis direction of the magnetic core 39. The spring stopper 306 is a stopper that limits the position of the yoke force spring 310. The yoke force spring 310 is composed of a leaf spring as an elastic body. The second yoke portion 302 is displaceably held in the central axis direction of the electromagnetic suction valve 3 by the yoke force spring 310. In addition, the second yoke portion 302 and the magnetic core 39 are configured in a state where the surfaces are in contact with each other by the surface contact portion 309. The second yoke portion 302 is displaceably held in the radial direction of the electromagnetic suction valve 3 by the surface contact portion 309.

[0072] A small gap 315 is ensured between the outer circumference of the second yoke part 302 and the inner circumference of the first yoke part 301. The gap 315 is set to a range of several μm to several tens of μm, for example, to position the first yoke part 301 and the second yoke part 302 or to facilitate the passage of magnetic flux between the first yoke part 301 and the second yoke part 302.

[0073] The armature 36 is supported by the fixed core 304 so as to be freely movable in the direction of the central axis of the rod 33. The fixed core 304 is fixed to the pump body 1 by a welding portion 312. The magnetic core 39 and the fixed core 304 are connected by a ring 307 as a connecting member. The ring 307 is a member for sealing the fuel present in the electromagnetic suction valve 3. The ring 307 is formed in a cylindrical shape. The ring 307 is made of a non-magnetic material so that the magnetic flux can easily pass between the magnetic core 39 and the armature 36. As a non-magnetic material constituting the ring 307, for example, stainless steel such as SUS304 can be considered.

[0074] The ring 307 is fixed to the fixed core 304 by the welding part 313, and is fixed to the magnetic core 39 by the welding part 314. In detail, one end side of the center axis direction of the ring 307 is fitted to the fixed core 304, and the ring 307 and the fixed core 304 are fixed by welding through the welding part 313 located at the fitting part. In addition, the other end side of the center axis direction of the ring 307 is fitted to the magnetic core 39, and the ring 307 and the magnetic core 39 are fixed by welding through the welding part 314 located at the fitting part.

[0075] The ring 307 is arranged to be opposite to the coil winding portion 60 via a gap D1 (mm) in the radial direction of the electromagnetic suction valve 3. Therefore, the ring 307 corresponds to the prescribed portion. The radial direction of the electromagnetic suction valve 3 is a direction orthogonal to the central axis of the rod 33. The gap D1 is formed by the wire tube 305. In detail, the gap D1 is ensured between the inner peripheral surface of the wire tube 305 and the outer peripheral surface of the ring 307 opposite thereto. The gap D1 corresponds to the first gap.

[0076] On the other hand, the second yoke portion 302 and the magnetic core 39 form a gap D2 (mm) in the radial direction of the electromagnetic suction valve 3. In detail, the gap D2 is ensured between the inner circumferential surface of the second yoke portion 302 and the outer circumferential surface of the magnetic core 39 opposite thereto. The gap D2 is a gap formed in the portion where the inner circumferential surface of the second yoke portion 302 and the outer circumferential surface of the magnetic core 39 are parallel and close to each other, and is not a gap formed by the thin-walled portion 39a of the magnetic core 39. The gap D2 is equivalent to the second gap. Compared with the size of the above-mentioned gap 315 being of the order of μm, the sizes of the gaps D1 and D2 are both of a different order of magnitude from the gap 315, namely, of the order of mm.

[0077] When a traffic accident such as a collision of a car occurs, an impact force (impact load) from the radial outside to the inside of the electromagnetic suction valve 3 is applied to the bobbin 305 of the coil winding portion 60 or the first yoke portion 301 of the magnetic circuit structure portion 70 . Figure 6 As an example, it is assumed that the impact force F is applied to the first yoke portion 301. In this case, the impact force F cannot be withstood by the press-in force of the press-in portion 311 alone. Therefore, not only the first yoke portion 301 but also the bobbin 305 fixed to the first yoke portion 301 and the electromagnetic coil 35 wound on the bobbin 305 are subjected to the impact force F. Figure 6 The P position is used as the center for rotation in the R direction. In this specification, the “P position” is also referred to as the “rotation center P”. The rotation center P exists at the center of the fitting hole of the first yoke part 301 in the press-fit part 311 that fits with the fixed core 304 .

[0078] Figure 6In the figure, L1 (mm) is the distance from the rotation center P to the gap D1, and L2 (mm) is the distance from the rotation center P to the gap D2. The reference position of the gap D1 of the specified distance L1 exists at the end of the gap D1 closest to the rotation center P in the direction of the center axis of the ring 307. In addition, the reference position of the gap D2 of the specified distance L2 exists at the end of the gap D2 closest to the rotation center P in the direction of the center axis of the magnetic core 39. The center axis direction of the ring 307 and the center axis direction of the magnetic core 39 are consistent with the center axis direction of the electromagnetic suction valve 3 when no impact force F is applied. According to Figure 6 It can be seen that the gap D2 is formed at a position farther from the rotation center P than the gap D1.

[0079] Figure 6 In the comparison shown, a value obtained by dividing the gap D1 by the distance L1 and a value obtained by dividing the gap D2 by the distance L2 satisfy the relationship (condition) of the following formula (1). D2 / L2<D1 / L1· · · (1)

[0080] Therefore, when the impact force F is applied to the first yoke portion 301, the second yoke portion 302 and the magnetic core 39 come into contact at portion A before the bobbin 305 and the ring 307 come into contact. As a result, a moment centered on the rotation center P is generated at the welded portions 312, 313, 314 and the thin-walled portion 39a of the magnetic core 39. If the moment exceeds the allowable value, the welded portions 312, 313, 314 or the thin-walled portion 39a of the magnetic core 39 may be damaged, and the fuel in the electromagnetic suction valve 3 may leak.

[0081] Therefore, in this embodiment 7, Figure 7 As shown, the following structure is adopted: the value obtained by dividing the gap D1 by the distance L1 and the value obtained by dividing the gap D2 by the distance L2 satisfy the relationship (condition) of the following formula (2). In addition, the structure of the electromagnetic suction valve involved in this embodiment is basically the same as the structure of the electromagnetic suction valve involved in the comparative method, except for the difference between the above formula (1) and the following formula (2). D2 / L2>D1 / L1· · · (2)

[0082] In this embodiment, it can be understood from the above formula (2) that the size of each gap D1, D2 is set so that the longer the distance L1, L2 from the rotation center P to the gap D1, D2 becomes, the larger the size of the gap D1, D2 becomes. As a result, the gap D1 formed by the portion where the distance L1 to the rotation center P is shorter is relatively narrow, and the gap D2 formed by the portion where the distance L2 to the rotation center P is longer is relatively wide. In other words, the gaps D1, D2 are set to have a larger size as they are farther away from the rotation center P. Therefore, when the above-mentioned impact force F is applied to the first yoke part 301, the coil winding part 60 and the ring 307 come into contact first. At this time, the coil winding part 60 and the ring 307 come into contact at part B. In addition, the part that comes into contact with the ring 307 is the wire tube 305. The "first" mentioned here means "before other parts" in a broad sense, and means "at least before the second yoke part 302 and the magnetic core 39 come into contact" in a narrow sense. Then, if a structure that satisfies the relationship of the above formula (2) is adopted, even when the above-mentioned impact force F is applied to the first yoke part 301 , contact between the second yoke part 302 and the magnetic core 39 can be avoided.

[0083] As described above, in the present embodiment, the size of the gap D1 formed between the coil winding portion 60 and the ring 307 is set so that when the impact force F from the radial outside toward the inside of the electromagnetic suction valve 3 is applied to the first yoke portion 301 (or the coil winding portion 60), the coil winding portion 60 and the ring 307 come into contact first. As a result, the moment acting on the welding portions 312, 313, and 314 with the rotation center P as the center can be smaller than that in the above-mentioned comparison method. Specifically, according to the present embodiment, the moment acting on the welding portions 312, 313, and 314 can be reduced to L1 / L2 times compared with the case of the comparison method. In addition, in the present embodiment, the impact force F applied to the first yoke portion 301 is received by the ring 307, and therefore, the thin-walled portion 39a of the magnetic core 39 does not generate a moment. Therefore, even when an unexpected impact force is applied to the coil winding portion 60 and the magnetic circuit structure portion 70 due to a traffic accident or the like, damage to the structural components of the electromagnetic suction valve 3 can be effectively suppressed. As a result, fuel leakage caused by damage to the structural components of the electromagnetic suction valve 3 can be prevented, and a safer high-pressure fuel supply pump 100 can be realized.

[0084] In this embodiment, the gap D1 is formed by the wire tube 305. The wire tube 305 is made of resin. Therefore, when the wire tube 305 contacts the ring 307 due to the impact force F, the resin constituting the wire tube 305 deforms to absorb the impact and reduce the moment.

[0085] In addition, in the present embodiment, the first gap D1, the second gap D2, the distance from the rotation center P to the first gap L1, and the distance from the rotation center P to the second gap L2 satisfy the relationship of "D2 / L2>D1 / L1". As a result, the wire tube 305 and the ring 307 can be brought into contact before the second yoke portion 302 and the magnetic core 39 come into contact, or the wire tube 305 and the ring 307 can be brought into contact without bringing the second yoke portion 302 and the magnetic core 39 into contact. Therefore, the moment acting on the above-mentioned welding portions 312, 313, and 314, or the moment acting on the thin-walled portion 39a of the magnetic core 39 can be suppressed to be small, thereby suppressing damage to the structural components of the electromagnetic suction valve 3.

[0086] Furthermore, in the present embodiment, the second yoke portion 302 is held displaceably in the radial direction of the electromagnetic suction valve 3 and in the direction of the central axis of the electromagnetic suction valve 3. Thus, when the impact force F is applied to the first yoke portion 301, the second yoke portion 302 is pressed by the first yoke portion 301 and appropriately displaced. Therefore, the impact can be prevented from being transmitted to the magnetic core 39.

[0087] In addition, in this embodiment, the connecting member connecting the fixed core 304 and the magnetic core 39 is composed of a ring 307 made of a non-magnetic material. Therefore, when the electromagnetic coil 35 is energized, the magnetic flux can efficiently pass between the armature 36 and the magnetic core 39, and a strong magnetic attraction can be generated between the two.

[0088] In addition, the present invention is not limited to the above-mentioned embodiments, but also includes various modified examples. For example, the content of the present invention is described in detail in the above-mentioned embodiments for easy understanding, but the present invention is not limited to having all the structures described in the above-mentioned embodiments. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments. In addition, the structure of other embodiments can also be added to the structure of a certain embodiment. In addition, a part of the structure of each embodiment can be deleted, added or replaced with other structures.

[0089] For example, the above-mentioned embodiment adopts the following structure: the fixed core 304 and the magnetic core 39 are connected by the ring 307 as a connecting member, but the present invention is not limited to this. For example, although not shown in the figure, the following structure can be adopted: a part of the fixed core 304 is extended to a position overlapping with the magnetic core 39, the extended core part is embedded with the magnetic core 39, and the core part is fixed to the magnetic core 39 by welding, etc., that is, a structure without a connecting member. When such a structure is adopted, the fixed core 304 opposite to the wire tube 305 of the coil winding part 60 via the gap D1 corresponds to the specified part. In addition, the ring 307 is provided as a connecting member, and the ring 307 is formed of stainless steel. In this case, the mechanical strength when subjected to impact force can be improved, so it is more preferred. Description of symbols

[0090] 1 Pump body 3 Solenoid suction valve 35 Solenoid coil 39 Magnetic core 60 Coil winding section 70 Magnetic circuit structure 100 High pressure fuel supply pump (fuel pump) 301 1st yoke part (yoke) 302 second yoke part (yoke) 304 fixed core 305 Wire tube 307 ring (connecting member, specified part) D1 gap (first gap) D1 gap (second gap) F Impact force L1 distance (first distance) L1 distance (second distance) P is the center of rotation.

Claims

1. A fuel pump, comprising an electromagnetic suction valve, the electromagnetic suction valve having: A coil winding portion formed by winding an electromagnetic coil around a bobbin; and The fuel pump is characterized in that the magnetic circuit structure portion forms a magnetic circuit when current flows through the electromagnetic coil. The magnetic circuit structure has: a yoke arranged to surround the coil winding portion; and a predetermined portion facing the coil winding portion via a gap in the radial direction of the electromagnetic suction valve. The size of the gap is set so that when an impact force from the outside to the inside in the radial direction of the electromagnetic suction valve is applied to the yoke or the coil winding portion, the coil winding portion and the predetermined portion come into contact first.

2. The fuel pump according to claim 1, characterized in that The gap is formed by the wire tube.

3. The fuel pump according to claim 1, characterized in that A first gap is formed between the coil winding portion and the predetermined portion as the gap, The magnetic circuit structure includes a yoke and a magnetic core that form a second gap in the radial direction of the electromagnetic suction valve. The second gap is formed at a position farther than the first gap when viewed from a rotation center of the yoke or the coil winding portion when the impact force is applied to the yoke or the coil winding portion. When the first gap is set to D1, the second gap is set to D2, the distance from the rotation center to the first gap is set to L1, and the distance from the rotation center to the second gap is set to L2, the following relationship is satisfied: D2 / L2>D1 / L1.

4. The fuel pump according to claim 3, characterized in that A portion of the yoke is displaceably held in a radial direction of the electromagnetic suction valve and in a central axis direction of the electromagnetic suction valve.

5. The fuel pump according to claim 3, characterized in that The magnetic circuit structure has a fixed core fixed to the pump body. The predetermined portion is formed by a connecting member connecting the fixed core and the magnetic core. The connecting member is made of non-magnetic material.

6. The fuel pump according to claim 5, characterized in that The connecting member is made of stainless steel.

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