Fuel pump

Abstract

This fuel pump comprises an electromagnetic suction valve having: a coil winding part formed by winding an electromagnetic coil on a bobbin; and a magnetic circuit formation part that constitutes a magnetic circuit when current flows in the electromagnetic coil. The magnetic circuit formation part has a yoke disposed so as to surround the coil winding part, and a prescribed portion opposing the coil winding part in the radial direction of the electromagnetic suction valve, with a gap therebetween. The size of the gap is set such that when impact force directed from the outside of the electromagnetic suction valve toward the inside in the radial direction is applied to the yoke or to the coil winding part, the coil winding part and the prescribed portion contact each other first.

Description

Technical Field

[0006] , ,

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

Background Art

[0002] In an internal combustion engine (engine) such as an automobile, a fuel pump provided with an electromagnetic suction valve that pressurizes fuel and discharges fuel at a desired flow rate is widely used (for example, see Patent Document 1). The fuel pump described in Patent Document 1 includes, in addition to a suction valve portion, a magnetic circuit configuration portion, and a coil winding portion that constitute an electromagnetic suction valve, a pump body, a cylinder that forms a pressurization chamber, a plunger slidably held by the cylinder, and a discharge valve mechanism.

[0003] When a fuel pump is mounted on an engine, a magnetic circuit configuration portion or a coil winding portion, which is a part of the electromagnetic suction valve, is arranged in a state of protruding outward from the pump body. Therefore, for example, when a traffic accident involving a collision of an automobile or the like occurs, an impact force (impact load) is applied to the solenoid mechanism portion or the coil portion. The magnitude of the impact force is predicted in advance by a collision test, simulation, or the like, and the dimensions of each part of the fuel pump are set based on this prediction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in order to realize a safer fuel pump, it is desirable to make structural improvements in advance so that even when an impact force exceeding the assumption is applied to the yoke or the like, the components of the electromagnetic suction valve are not damaged.

[0006] The object of the present invention is to provide a fuel pump that can effectively suppress damage to the components of an electromagnetic intake valve even when an impact force is applied to the coil winding portion or magnetic circuit component that constitutes the electromagnetic intake valve. [Means for solving the problem]

[0007] To address the above issues, for example, the configuration described in the claims is adopted. The present invention includes several means for solving the above problems, but one example is a fuel pump equipped with an electromagnetic intake valve having a coil winding section formed by winding an electromagnetic coil on a bobbin, and a magnetic circuit component section which is a magnetic material that constitutes a magnetic circuit when current flows through the electromagnetic coil. The magnetic circuit component section has a yoke arranged to surround the coil winding section and a fixed core fixed to the pump body. And the magnetic core and The coil winding section is arranged to make a full circle around the magnetic core, The magnetic core is directly connected to the fixed core, or connected to the fixed core via a connecting member, and the fixed core is welded to the magnetic core or the connecting member at the weld, and the magnetic core is welded to the fixed core or the connecting member at the weld, The electromagnetic intake valve has a predetermined portion that faces the coil winding portion in the radial direction of the electromagnetic intake valve via a first gap. The magnetic core faces a portion of the yoke, and a second gap is formed between the magnetic core and the portion of the yoke. The second gap is formed at a position further away from the first gap than the first gap when an impact force is applied to the yoke or the coil winding portion from the outside to the inside in the radial direction of the electromagnetic intake valve, and satisfies the relationship D2 / L2 > D1 / L1, where D1 is the first gap, D2 is the second gap, L1 is the distance from the center of rotation to the first gap, and L2 is the distance from the center of rotation to the second gap. When an impact force is applied to the yoke or the coil winding portion from the outside to the inside in the radial direction of the electromagnetic intake valve, the coil winding portion and the predetermined portion make contact first. [Effects of the Invention]

[0008] According to the present invention, even when an impact force is applied to the coil winding portion or magnetic circuit portion constituting the electromagnetic intake valve, damage to the components of the electromagnetic intake valve can be effectively suppressed. Other issues, configurations, and effects not mentioned above will be clarified by the following description of the embodiments. [Brief explanation of the drawing]

[0009] [Figure 1] This is an overall configuration diagram of a fuel supply system using a fuel pump according to this embodiment. [Figure 2] This is a longitudinal cross-sectional view of the high-pressure fuel supply pump taken at position II-II in Figure 4. [Figure 3] This is a longitudinal cross-sectional view of the high-pressure fuel supply pump taken at position III-III in Figure 4. [Figure 4] This is a cross-sectional view of a high-pressure fuel supply pump, taken parallel to the horizontal plane. [Figure 5] This is a longitudinal cross-sectional view of the high-pressure fuel supply pump taken at position VV in Figure 4. [Figure 6] This is a longitudinal cross-sectional view illustrating the configuration of an electromagnetic intake valve in a comparative form. [Figure 7] This is a longitudinal cross-sectional view illustrating the configuration of an electromagnetic intake valve according to an embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will now be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same function or configuration are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] [Fuel supply system] Figure 1 is an overall diagram of the fuel supply system using the fuel pump according to this embodiment. As shown in Figure 1, the fuel supply system comprises 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 multiple injectors 107. The components of the high-pressure fuel supply pump 100 are integrated into the pump body 1.

[0012] Fuel is stored in the fuel tank 103. The fuel in the fuel tank 103 is pumped up by the feed pump 102. The feed pump 102 is driven based on a signal sent from the ECU 101 to the feed pump 102 to pump up the fuel. The fuel pumped up by the feed pump 102 is pressurized to an appropriate pressure by a pressure regulator (not shown) and sent to the low-pressure fuel inlet 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 drive of the feed pump 102 and pumps it to the common rail 106. A fuel pressure sensor 105 and a plurality of injectors 107 are attached to the common rail 106.

[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 an appropriate injection fuel amount (target injection fuel length), an appropriate fuel pressure (target fuel pressure), etc. based on engine state quantities (such as crank rotation angle, throttle opening, engine speed, fuel pressure, etc.) obtained from various sensors.

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

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

[0017] The high-pressure fuel supply pump 100 has a pressure pulsation reduction mechanism 9, an electromagnetic suction valve 3 which is a capacity variable mechanism, a relief valve 4 (Fig. 2), and a discharge valve 8. The fuel flowing in from the low-pressure fuel inlet 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 flows into the pressurizing chamber 11 through the suction passage 1d formed in the pump body 1 after passing through the valve portion 32. A plunger 2 is inserted into the pressurizing chamber 11 so as to be reciprocable. The plunger 2 is reciprocated by the power transmitted by the engine cam 91 (Fig. 2).

[0019] In the pressurizing chamber 11, fuel is sucked from the electromagnetic suction valve 3 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke. When the fuel pressure in the pressurizing chamber 11 exceeds a predetermined value due to this 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 discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic suction valve 3. And the opening and closing of the electromagnetic suction valve 3 is controlled by the ECU 101.

[0020] [High-pressure fuel supply pump] Fig. 2 is a longitudinal sectional view of the high-pressure fuel supply pump taken at the II-II position in Fig. 4. Fig. 3 is a longitudinal sectional view of the high-pressure fuel supply pump taken at the III-III position in Fig. 4. Fig. 4 is a cross-sectional view of the high-pressure fuel supply pump taken parallel to the horizontal plane. Fig. 5 is a longitudinal sectional view of the high-pressure fuel supply pump taken at the V-V position in Fig. 4.

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

[0022] The first chamber 1a is a cylindrical space provided in the pump body 1. The centerline 1A of the first chamber 1a coincides with the centerline of the pump body 1. One end of the plunger 2 is inserted into the first chamber 1a. The plunger 2 reciprocates within 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 the diameter of the first chamber 1a. The center line of the second chamber 1b (not shown) is perpendicular to the center line 1A of the first chamber 1a. A relief valve 4 is located in the second chamber 1b.

[0024] The first chamber 1a and the second chamber 1b are connected by a circular connecting hole 1e. The diameter of the connecting hole 1e is the same as the diameter 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 centerline 1A of the first chamber 1a, which passes through the center of the connecting hole 1e, is perpendicular to the centerline of the second chamber 1b.

[0025] As shown in Figures 3 and 5, the diameter of the communication hole 1e is larger than the diameter of the second chamber 1b. The communication hole 1e has a tapered surface 1f. In a cross-section perpendicular to the center line of the second chamber 1b, the diameter of the tapered surface 1f gradually decreases towards the second chamber 1b. This allows the fuel that has passed through the relief valve 4 to smoothly return to the pressurized chamber 11 via the tapered surface 1f.

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

[0027] The cylinder 6 is formed in a cylindrical shape. The cylinder 6 is press-fitted into the third chamber 1c of the pump body 1 at the press-fit 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 between the first chamber 1a and the third chamber 1c. Only the press-fit portion 6a of the cylinder 6 is press-fitted, and the cylinder diameter on the pressurizing chamber 11 side of the press-fit portion 6a is set to be smaller than the diameter of the third chamber 1c. Therefore, on the pressurizing chamber 11 side of the press-fit portion 6a, there is a clearance between the outer surface of the cylinder 6 and the inner surface of the third chamber 1c. The plunger 2 is in slidable contact with the inner surface of the cylinder 6.

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

[0029] A tappet 92 is positioned at the lower end of the plunger 2. The tappet 92 raises and lowers the plunger 2 by converting the rotational motion of the cam 91, which is attached to the engine's camshaft, into vertical motion. The plunger 2 receives the force of a spring 16 via a retainer 15, and is biased toward the cam 91 by this 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 in accordance with the rotation of the cam 91. The plunger 2, together with the tappet 92, reciprocates (rises and falls) in the vertical direction shown in Figure 5, thereby changing the volume of the pressurizing chamber 11.

[0030] A seal holder 17 is positioned between the cylinder 6 and the retainer 15. The seal holder 17 is cylindrical, and the plunger 2 is inserted into this cylindrical portion. The seal holder 17 forms a sub-chamber 17a. The seal holder 17 holds the plunger seal 18 at its lower end, which is on the retainer 15 side. The sub-chamber 17a is positioned closer to the cylinder 6 than the plunger seal 18. The sub-chamber 17a is formed from around the small diameter portion 2b of the plunger 2 to around the small diameter portion of the cylinder 6.

[0031] The plunger seal 18 is in slidable contact with the outer circumferential 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, preventing the fuel in the sub-chamber 17a from flowing into the engine. The plunger seal 18 also prevents lubricating oil (including engine oil) that lubricates the sliding parts inside the engine from flowing into the pump body 1.

[0032] In Figure 2, the plunger 2 reciprocates in the vertical direction. When the plunger 2 descends, the volume of the pressurized chamber 11 expands, and when the plunger 2 rises, the volume of the pressurized chamber 11 decreases. In other words, the plunger 2 is arranged to reciprocate in a direction that expands and contracts the volume of the pressurized chamber 11.

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

[0034] The sub-chamber 17a is in communication with the low-pressure fuel chamber 10 through the fuel passage 10c (Figures 3 and 5). When the plunger 2 descends, a fuel flow is generated from the sub-chamber 17a toward the low-pressure fuel chamber 10, and when the plunger 2 rises, a fuel flow is generated from the low-pressure fuel chamber 10 toward the sub-chamber 17a. This reduces the fuel flow rate to and from the pump during the intake or return stroke of the high-pressure fuel supply pump 100, thereby reducing pressure pulsations generated inside the high-pressure fuel supply pump 100.

[0035] As shown in Figure 3, a low-pressure fuel chamber 10 is provided at the top of the pump body 1. A suction joint 5 is attached to the side of the pump body 1. The suction joint 5 is connected to a low-pressure pipe 104 (Figure 1). The low-pressure pipe 104 is a pipe through which fuel supplied from the fuel tank 103 (Figure 1) passes. The fuel in the fuel tank 103 is supplied to the inside of the pump body 1 through the suction joint 5.

[0036] The intake joint 5 has a low-pressure fuel inlet 51 connected to the low-pressure piping 104 and an intake passage 52 communicating with the low-pressure fuel inlet 51. Fuel that has passed through the intake passage 52 is supplied to the low-pressure fuel chamber 10 after passing through the intake filter 53. The intake filter 53 is located inside the pump body 1. The intake filter 53 removes foreign matter present in the fuel and prevents 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 passage 10a and an intake passage 10b (Figure 2). A pressure pulsation reduction mechanism 9 is provided in the low-pressure fuel passage 10a. When fuel that has flowed into the pressurized chamber 11 is returned to the intake passage 10b through the open electromagnetic intake valve 3, pressure pulsations occur in the low-pressure fuel chamber 10. The pressure pulsation reduction mechanism 9 reduces the propagation of pressure pulsations generated in the high-pressure fuel supply pump 100 to the low-pressure piping 104.

[0038] The pressure pulsation reduction mechanism 9 is composed of, for example, a metal diaphragm damper. The metal diaphragm damper has a structure in which two corrugated disc-shaped metal plates are bonded together at 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 pulsations by expanding and contracting the space formed between the two disc-shaped metal plates.

[0039] The intake passage 10b is connected to the intake port 31b of the electromagnetic intake valve 3 (Figure 2). The fuel that has passed through the low-pressure fuel passage 10a reaches the intake port 31b of the electromagnetic intake valve 3 through the intake passage 10b.

[0040] [Electromagnetic intake valve] Next, the configuration and operation of the electromagnetic suction valve provided in the high-pressure fuel supply pump according to this embodiment will be described. As shown in Figures 2 and 4, the electromagnetic suction valve 3 is inserted into a lateral hole formed in the pump body 1. The electromagnetic suction valve 3 includes a suction valve seat 31, a valve section 32, a rod 33, a rod biasing spring 34, an electromagnetic coil 35, an anchor 36, a stopper 37, a valve biasing spring 38, and an anchor biasing spring 36a.

[0041] The intake valve seat 31 is press-fitted into a lateral hole in the pump body 1. The intake valve seat 31 is formed in a cylindrical shape. A seating portion 31a is provided on the inner circumference of the intake valve seat 31. An intake port 31b is also formed in the intake valve seat 31. The intake port 31b is formed to extend from the outer circumference to the inner circumference of the intake valve seat 31. The intake port 31b communicates with the intake passage 10b in the low-pressure fuel chamber 10 described above.

[0042] A stopper 37 is positioned inside the lateral hole of the pump body 1. The stopper 37 is positioned in the direction of the central axis of the rod 33, facing the seating portion 31a of the suction valve seat 31. The valve portion 32 is positioned between the stopper 37 and the seating portion 31a. A valve biasing spring 38 is positioned between the stopper 37 and the valve portion 32. The valve biasing spring 38 biases the valve portion 32 toward the seating portion 31a.

[0043] The valve portion 32 closes the communication between the intake port 31b and the pressurized chamber 11 by contacting the seat portion 31a. This causes the electromagnetic intake valve 3 to be in a closed state. Conversely, the valve portion 32 opens the communication between the intake port 31b and the pressurized chamber 11 by contacting the stopper 37. This causes the electromagnetic intake valve 3 to be in an open state.

[0044] The rod 33 passes through a cylindrical hole formed in the intake valve seat 31. One end of the rod 33 is in contact with the valve portion 32. The rod biasing spring 34 biases the valve portion 32 towards the stopper 37, i.e., in the direction of opening the electromagnetic intake valve 3, via the rod 33. One end of the rod biasing spring 34 is engaged with a flange portion 33a formed on the other end of the rod 33. The other end of the rod biasing spring 34 is engaged with a magnetic core 39. The magnetic core 39 is positioned to surround the rod biasing spring 34.

[0045] The anchor 36 is positioned facing the end face of the magnetic core 39. The anchor 36 is also engaged with the flange portion 33a of the rod 33 on the opposite end from the rod biasing member 34 described above. The anchor biasing spring 36a biases the anchor 36 to press against the flange portion 33a of the rod 33. The electromagnetic coil 35 is arranged to encircle the magnetic core 39. A terminal member 40 is electrically connected to the electromagnetic coil 35. The terminal member 40 is a component for conducting current through the electromagnetic coil 35. The terminal member 40 is provided on the connector 46.

[0046] When no current flows through the electromagnetic coil 35, i.e., when no power is supplied, the rod 33 is biased in the valve-opening direction by the rod biasing spring 34, pressing the valve portion 32 in the valve-opening direction. As a result, the valve portion 32 moves away from the seat portion 31a and contacts the stopper 37, causing the electromagnetic intake valve 3 to open. In other words, the electromagnetic intake valve 3 is a normally open type electromagnetic valve that opens when no power is supplied.

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

[0048] In contrast, when current flows through the electromagnetic coil 35 in the aforementioned de-energized state, magnetic flux is generated inside the anchor 36, fixed core 304, first yoke portion 301, second yoke portion 302, and magnetic core 39. This generates a magnetic attractive force between the magnetic core 39 and the anchor 36, and this magnetic attractive force pulls the anchor 36 toward the magnetic core 39, i.e., in the valve closing direction. As a result, the anchor 36 moves against the biasing force of the rod biasing spring 34 and comes into contact with the end face of the magnetic core 39. When the anchor 36 moves in the valve closing direction in this way, the rod 33 moves together with the anchor 36. Therefore, the valve portion 32 is released from the biasing force toward the valve opening direction and moves in the valve closing direction due to the biasing force of the valve biasing spring 38. When the valve portion 32 comes into contact with the seat portion 31a of the suction valve seat 31, the electromagnetic suction valve 3 becomes closed.

[0049] [Discharge valve] Next, the configuration and operation of the discharge valve provided in the high-pressure fuel supply pump according to this embodiment will be described. As shown in Figures 4 and 5, 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 that communicates with the pressurizing chamber 11, a valve portion 82 that moves toward and away from the discharge valve seat 81, a discharge valve spring 83 that biases the valve portion 82 toward the discharge valve seat 81, a discharge valve stopper 84 that determines the stroke (travel distance) of the valve portion 82, and a plug 85 that blocks fuel leakage to the outside.

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

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

[0052] In the discharge valve 8 configured as described above, when there is no fuel pressure difference (fuel differential pressure) 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 biasing force of the discharge valve spring 83. As a result, the discharge valve 8 is in a closed state. Conversely, when the fuel pressure in the pressurizing chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 87, the valve portion 82 moves towards the discharge valve stopper 84 against the biasing 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 closed, the high-pressure fuel in the pressurizing chamber 11 passes through the discharge valve 8 and reaches the discharge valve chamber 87. The fuel that reaches the discharge valve chamber 87 passes through the discharge passage 12a and fuel outlet 12b of the discharge joint 12 and is discharged to the common rail 106 (Figure 1). The discharge valve 8 functions as a check valve that restricts the direction in which fuel flows, based on the configuration and operation described above.

[0054] [Relief valve] The relief valve 4 shown in Figure 2 is configured to operate when a problem occurs in the common rail 106 or the components beyond it, causing the common rail 106 to exceed a predetermined pressure and return the fuel in the discharge passage 12a to the pressurizing chamber 11. The relief valve 4 is positioned higher than the discharge valve 8 (Figure 5) in the direction of the reciprocating motion of the plunger 2 (vertical direction).

[0055] The relief valve 4 comprises a relief spring 41, a relief valve holder 42, a valve portion 43, and a seat member 44. The relief valve 4 is inserted through a lateral hole in the pump body 1 into which the discharge joint 12 is inserted, and is positioned 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 holder 42. The relief valve holder 42 engages with the valve portion 43. The biasing force of the relief spring 41 is applied to the valve portion 43 via the flange portion of the relief valve holder 42.

[0056] The valve portion 43 is pressed against the seat member 44 by the biasing 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 state. The direction of movement of the relief valve holder 42 and the valve portion 43 is perpendicular to the direction in which the plunger 2 reciprocates. The centerline of the relief valve holder 42 in the relief valve 4 is perpendicular to the centerline of the plunger 2.

[0057] The seat member 44 forms a fuel passage in the portion facing the valve portion 43. The seat member 44 is formed in a cylindrical shape. The internal space of the seat member 44 is in communication with the fuel passage. The internal space of the seat member 44 is also in communication with the discharge passage 12a on the side opposite to the valve portion 43. The movement of fuel between the upstream side of the pressurizing chamber 11 and the downstream side of the seat member 44 is blocked when the valve portion 43 contacts (closely seals) the seat member 44 and blocks the fuel passage.

[0058] When the pressure in the common rail 106 and the components beyond it increases, the fuel in the seat member 44 presses against the valve portion 43 against the biasing force of the relief spring 41. As a result, the valve portion 43 moves away from the seat member 44. Consequently, the relief valve 4 opens. When the relief valve 4 opens, the fuel in the discharge passage 12a returns to the pressurized chamber 11 through the fuel passage formed between the valve portion 43 and the seat member 44. Therefore, the pressure required to open the relief valve 4 is determined by the biasing force of the relief spring 41.

[0059] The direction of movement of the valve portion 43 in the relief valve 4 is different from the direction of movement of the valve portion 82 in the discharge valve 8 described above. Specifically, the direction of movement of the valve portion 82 in the discharge valve 8 is the first radial direction of the pump body 1, while the direction of movement of the valve portion 43 in the relief valve 4 is the second radial direction, which is different from the first radial direction of the pump body 1. This allows the discharge valve 8 and the relief valve 4 to be positioned so that they do not overlap each other in the vertical direction, making effective use of the space inside the pump body 1 and enabling miniaturization of the pump body 1.

[0060] [Operation of the high-pressure fuel supply pump] Next, the operation of the high-pressure fuel supply pump according to this embodiment will be explained using Figures 2 and 4. Figure 2 shows the plunger 2 in the state where it has risen to top dead center. When the plunger 2 descends from the state shown in Figure 2, if the electromagnetic intake valve 3 is open, fuel flows from the intake passage 1d into the pressurizing chamber 11. Hereinafter, the stroke in which the plunger 2 descends will be referred to as the intake stroke. On the other hand, when the plunger 2 rises from its bottom dead center, if the electromagnetic intake valve 3 is closed, the fuel in the pressurizing chamber 11 is pushed by the plunger 2 and pressurized. The pressurized fuel passes through the discharge valve 8 and is pumped to the common rail 106 (Figure 1). Hereinafter, the stroke in which the plunger 2 rises will be referred to as the rising stroke.

[0061] As described above, if the electromagnetic intake valve 3 is closed during the upward stroke, the fuel drawn into the pressurizing chamber 11 in the intake stroke of the previous cycle is pressurized. At this time, the pressurized fuel is discharged towards the common rail 106. On the other hand, if the electromagnetic intake valve 3 is open during the upward stroke, the fuel in the pressurizing chamber 11 is pushed back towards the intake passage 1d and is not discharged towards the common rail 106. Thus, the discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve 3. The opening and closing of the electromagnetic intake valve 3 is controlled by the ECU 101.

[0062] During the intake stroke, the volume of the pressurized chamber 11 increases, and the fuel pressure inside the pressurized chamber 11 decreases. This reduces the fluid pressure difference between the intake port 31b and the pressurized chamber 11 (hereinafter referred to as the "fluid pressure difference before and after the valve portion 32"). When the biasing force of the rod biasing spring 34 becomes 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 intake valve seat 31, and the electromagnetic intake valve 3 opens.

[0063] After the intake stroke is completed, the system moves to the upward stroke. At this time, the electromagnetic coil 35 is kept in an unenergized state. Therefore, no magnetic attraction force is generated between the anchor 36 and the magnetic core 39. In this state, the valve section 32 is subjected to both an opening force and a closing force. The opening force acting on the valve section 32 is a force corresponding to the difference between the biasing force of the rod biasing spring 34 and the biasing force of the valve biasing spring 38. The closing force acting on the valve section 32 is a force due to the fluid force generated when fuel flows back from the pressurizing chamber 11 to the low-pressure fuel passage 10a.

[0064] In this state, in order for the electromagnetic intake valve 3 to maintain the open state, the difference between the biasing force of the rod biasing spring 34 and the biasing force of the valve biasing spring 38 is set to be greater than the fluid force described above. The volume of the pressurizing chamber 11 decreases as the plunger 2 rises. Therefore, the fuel that was drawn into the pressurizing chamber 11 is returned to the intake port 31b by passing between the valve portion 32 and the seating portion 31a. Thus, the pressure inside the pressurizing chamber 11 does not rise. This process is called the return process.

[0065] During the return stroke, when the ECU 101 (Figure 1) provides a control signal to the electromagnetic intake valve 3, current flows through the electromagnetic coil 35 via the terminal member 40. When current flows through the electromagnetic coil 35, a magnetic flux is generated around it. This magnetic flux is mainly generated inside the anchor 36, fixed core 304, first yoke portion 301, second yoke portion 302, and magnetic core, which are made of magnetic material. As a result, a magnetic attractive force is generated between the magnetic core 39 and the anchor 36. Therefore, the anchor 36 is attracted to the magnetic core 39. At this time, the rod 33 moves in the valve closing direction together with the anchor 36, against the biasing force of the rod biasing spring 34.

[0066] As the rod 33 and anchor 36 move in the valve-closing direction, the valve portion 32 is released from the biasing force in the valve-opening direction. Therefore, the valve portion 32 moves in the valve-closing direction due to the biasing force of the valve biasing spring 38 and the fluid force caused by the fuel flowing into the intake passage 10b. When the valve portion 32 contacts (seats) the seating portion 31a of the intake valve seat 31, the electromagnetic intake valve 3 becomes closed.

[0067] After the electromagnetic intake valve 3 closes, the fuel in the pressurizing chamber 11 is pressurized as the plunger 2 rises. When the fuel pressure exceeds a predetermined pressure, the fuel is discharged through the discharge valve 8 to the common rail 106 (Figure 1). This process is called the discharge process. The process in which the plunger 2 moves from bottom dead center to top dead center, i.e., the upward process, consists of a return process and a discharge process. The ECU 101 can control the amount of fuel (high-pressure fuel) discharged to the common rail 106 by controlling the timing of energizing the electromagnetic coil 35 of the electromagnetic intake valve 3.

[0068] Specifically, if the timing of energizing the electromagnetic coil 35 is advanced, the proportion of the return stroke decreases and the proportion of the discharge stroke increases during the upward stroke. As a result, less fuel is returned to the intake passage 10b and more fuel is discharged into the common rail 106. On the other hand, if the timing of energizing the electromagnetic coil 35 is delayed, the proportion of the return stroke increases and the proportion of the discharge stroke decreases during the upward stroke. As a result, more fuel is returned to the intake passage 10b and less fuel is discharged into the common rail 106. Therefore, by controlling the timing of energizing the electromagnetic coil 35, the ECU 101 can control the amount of fuel discharged into the common rail 106 according to the amount required by the engine (internal combustion engine).

[0069] [Electromagnetic intake valve] Figure 6 is a longitudinal cross-sectional view illustrating the configuration of the electromagnetic intake valve in the comparative configuration. Note that the comparative configuration has the same configuration as this embodiment, with the exception of some components. In Figure 6, the coil winding section 60 includes an electromagnetic coil 35 and a bobbin 305. The electromagnetic coil 35 is wound on the resin bobbin 305 by aligned winding. The bobbin 305 is fixedly positioned inside the first yoke section 301.

[0070] The magnetic circuit component 70 constitutes a magnetic circuit for passing magnetic flux when current flows through the electromagnetic coil 35. The magnetic circuit component 70 is composed of an anchor 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 this embodiment, as an example, the first yoke portion 301 and the second yoke portion 302 are separate parts, but they may be integrated. The members constituting the magnetic circuit component 70 are made of magnetic material.

[0071] The first yoke portion 301 is positioned to surround the coil winding portion 60. The first yoke portion 301 is press-fitted and fixed to the fixed core 304 by a press-fit portion 311. The second yoke portion 302 is pressed against the magnetic core 39 by the biasing force of the yoke biasing spring 310. The yoke biasing spring 310 is positioned between the second yoke portion 302 and a spring stopper 306 in the central axis direction of the magnetic core 39. The spring stopper 306 is a stopper that restricts the position of the yoke biasing spring 310. The yoke biasing spring 310 is made of a leaf spring as an elastic body. The second yoke portion 302 is held by the yoke biasing spring 310 so as to be displaceable in the central axis direction of the electromagnetic intake valve 3. Furthermore, the second yoke portion 302 and the magnetic core 39 are positioned so that their surfaces are in contact with each other at a surface contact portion 309. The second yoke portion 302 is held by the surface contact portion 309 so as to be displaceable in the radial direction of the electromagnetic intake valve 3.

[0072] A small clearance 315 is maintained between the outer circumferential surface of the second yoke portion 302 and the inner circumferential surface of the first yoke portion 301. The clearance 315 is set to a range of several micrometers to several tens of micrometers in order to position the first yoke portion 301 and the second yoke portion 302 and to facilitate the passage of magnetic flux between the first yoke portion 301 and the second yoke portion 302.

[0073] The anchor 36 is supported by a fixed core 304 so as to be movable in the central axis direction of the rod 33. The fixed core 304 is fixed to the pump body 1 by a welded joint 312. The magnetic core 39 and the fixed core 304 are connected by a ring 307, which acts as a connecting member. The ring 307 is a member that seals the fuel present in the electromagnetic intake valve 3. The ring 307 is formed in a cylindrical shape. The ring 307 is made of a non-magnetic material so as to allow magnetic flux to easily pass between the magnetic core 39 and the anchor 36. A non-magnetic material that makes up the ring 307 could be stainless steel such as SUS304.

[0074] The ring 307 is fixed to the fixed core 304 by a welded joint 313 and to the magnetic core 39 by a welded joint 314. More specifically, one end of the ring 307 in the direction of the central axis is fitted to the fixed core 304, and the ring 307 and the fixed core 304 are fixed by welding at the welded joint 313 located at this fitting portion. The other end of the ring 307 in the direction of the central axis is fitted to the magnetic core 39, and the ring 307 and the magnetic core 39 are fixed by welding at the welded joint 314 located at this fitting portion.

[0075] The ring 307 is positioned so as to face the coil winding portion 60 in the radial direction of the electromagnetic suction valve 3 with a gap D1 (mm) between them. Thus, the ring 307 corresponds to a predetermined portion. The radial direction of the electromagnetic suction valve 3 is perpendicular to the central axis of the rod 33. The gap D1 is formed by the bobbin 305. More specifically, the gap D1 is secured between the inner circumferential surface of the bobbin 305 and the outer circumferential surface of the ring 307 facing it. 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 intake valve 3. More specifically, the gap D2 is secured between the inner circumferential surface of the second yoke portion 302 and the outer circumferential surface of the magnetic core 39 that faces it. The gap D2 is 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 corresponds to the second gap. While the dimension of the aforementioned clearance 315 is on the order of μm, the dimensions of gaps D1 and D2 are both on a completely different order of magnitude, i.e., on the order of mm.

[0077] When a traffic accident involving a collision with a vehicle occurs, an impact force (impact load) directed from the radially outer side to the inner side of the electromagnetic intake valve 3 may be applied to the bobbin 305 of the coil winding section 60 or the first yoke section 301 of the magnetic circuit component section 70. In Figure 6, as an example, a case in which an impact force F is applied to the first yoke section 301 is assumed. In that case, depending on the magnitude of the impact force F, the press-fitting section 311 alone may not be able to withstand it. As a result, not only the first yoke section 301 that has received the impact force F, but also the bobbin 305 fixed to the first yoke section 301 and the electromagnetic coil 35 wound around the bobbin 305 will rotate in the R direction around position P in Figure 6. In this specification, "position P" is also referred to as "center of rotation P". The center of rotation P is located at the center of the fitting hole of the first yoke section 301 that fits into the fixed core 304 in the press-fitting section 311.

[0078] In Figure 6, 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 that defines distance L1 is located at the end of the gap D1 closest to the rotation center P in the direction of the central axis of the ring 307. Similarly, the reference position of the gap D2 that defines distance L2 is located at the end of the gap D2 closest to the rotation center P in the direction of the central axis of the magnetic core 39. The direction of the central axis of the ring 307 and the direction of the central axis of the magnetic core 39 coincide with the direction of the central axis of the electromagnetic intake valve 3 when no impact force F is applied. As can be seen from Figure 6, the gap D2 is formed at a position further away from the rotation center P than the gap D1.

[0079] In the comparison configuration shown in Figure 6, 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) in equation (1) below. D2 / L2 <D1 / L1 ···(1)

[0080] Therefore, if the impact force F described above is applied to the first yoke portion 301, the second yoke portion 302 and the magnetic core 39 will come into contact at portion A before the bobbin 305 and the ring 307 come into contact. This generates a moment around the rotation center P in the welded portions 312, 313, 314 and the thin-walled portion 39a of the magnetic core 39. If this 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, potentially causing fuel to leak from the electromagnetic intake valve 3.

[0081] Therefore, in this embodiment, as shown in Figure 7, a configuration is adopted in which 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 equation (2) below. Note that the configuration of the electromagnetic intake valve according to this embodiment is basically the same as the configuration of the electromagnetic intake valve according to the comparative embodiment, except for the difference between equation (1) above and equation (2) below. D2 / L2 > D1 / L1 ... (2)

[0082] In this embodiment, as can be understood from equation (2) above, the dimensions of each gap D1 and D2 are set such that the dimensions of the gaps D1 and D2 increase as the distances L1 and L2 from the rotation center P increase. As a result, the gap D1 formed in the part where the distance L1 from the rotation center P is short becomes relatively narrow, and the gap D2 formed in the part where the distance L2 from the rotation center P is long becomes relatively wide. In other words, the dimensions of the gaps D1 and D2 are set to be larger as they get further away from the rotation center P. Therefore, when the impact force F described above is applied to the first yoke portion 301, the coil winding portion 60 and the ring 307 will come into contact first. At this time, the coil winding portion 60 and the ring 307 come into contact at portion B. The part that comes into contact with the ring 307 is the bobbin 305. The term "first" here means, in a broad sense, "before other parts," and in a narrow sense, "at least before the second yoke portion 302 and the magnetic core 39 come into contact." However, if a configuration that satisfies the relationship in equation (2) above is adopted, contact between the second yoke portion 302 and the magnetic core 39 can be avoided even when the aforementioned impact force F is applied to the first yoke portion 301.

[0083] As described above, in this embodiment, the dimensions of the gap D1 formed between the coil winding portion 60 and the ring 307 are set so that when an impact force F directed from the radially outside to the inside of the electromagnetic intake valve 3 is applied to the first yoke portion 301 (or coil winding portion 60), the coil winding portion 60 and the ring 307 make contact first. This makes it possible to reduce the moment acting on the welded portions 312, 313, and 314 with respect to the rotation center P compared to the comparative embodiment described above. Specifically, according to this embodiment, the moment acting on the welded portions 312, 313, and 314 can be reduced by L1 / L2 times compared to the comparative embodiment. Furthermore, in this embodiment, since the impact force F applied to the first yoke portion 301 is absorbed by the ring 307, no moment is generated in the thin-walled portion 39a of the magnetic core 39. Therefore, even if an unexpected impact force is applied to the coil winding portion 60 or the magnetic circuit component 70 due to a traffic accident or the like, damage to the components of the electromagnetic intake valve 3 can be effectively suppressed. As a result, it is possible to prevent fuel leaks caused by damage to the components of the electromagnetic intake valve 3, thereby realizing a safer high-pressure fuel supply pump 100.

[0084] Furthermore, in this embodiment, the gap D1 is formed by the bobbin 305. The bobbin 305 is made of resin. Therefore, when the bobbin 305 comes into contact with the ring 307 due to an impact force F, the impact can be absorbed by the deformation of the resin constituting the bobbin 305, and the above moment can be reduced.

[0085] Furthermore, in this embodiment, the first gap D1, the second gap D2, the distance L1 from the rotation center P to the first gap, and the distance L2 from the rotation center P to the second gap are configured to satisfy the relationship "D2 / L2 > D1 / L1". This allows the bobbin 305 and the ring 307 to come into contact before the second yoke portion 302 and the magnetic core 39 come into contact, or without the second yoke portion 302 and the magnetic core 39 coming into contact. Therefore, the moments acting on the welded portions 312, 313, and 314 and the moments acting on the thin-walled portion 39a of the magnetic core 39 can be kept small, thereby suppressing damage to the components of the electromagnetic intake valve 3.

[0086] Furthermore, in this embodiment, the second yoke portion 302 is held so as to be displaceable in the radial direction of the electromagnetic intake valve 3 and in the central axis direction of the electromagnetic intake valve 3. As a result, when an impact force F is applied to the first yoke portion 301, the second yoke portion 302 is pushed by the first yoke portion 301 and displaced appropriately. Therefore, it is possible to avoid the transmission of impact to the magnetic core 39.

[0087] Furthermore, in this embodiment, the connecting member that connects the fixed core 304 and the magnetic core 39 is made of a ring 307 made of a non-magnetic material. This allows magnetic flux to pass efficiently between the anchor 36 and the magnetic core 39 when the electromagnetic coil 35 is energized, generating a strong magnetic attraction between them.

[0088] It should be noted that the present invention is not limited to the embodiments described above, and includes various modifications. For example, although the embodiments described above are explained in detail to facilitate understanding of the present invention, the present invention is not necessarily limited to having all the configurations described in the embodiments described above. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to delete a part of the configuration of each embodiment, add other configurations, or replace other configurations.

[0089] For example, in the above embodiment, a configuration is adopted in which the fixed core 304 and the magnetic core 39 are connected by a ring 307 as a connecting member, but the present invention is not limited to this. For example, although not shown in the figures, a configuration may be adopted in which a part of the fixed core 304 is extended to a position that overlaps with the magnetic core 39, the extended core portion is fitted into the magnetic core 39, and the core portion is fixed to the magnetic core 39 by welding or the like, i.e., a configuration without a connecting member. When this configuration is adopted, the fixed core 304 that faces the bobbin 305 of the coil winding section 60 with a gap D1 in between corresponds to a predetermined portion. Furthermore, if the ring 307 is provided as a connecting member and the ring 307 is made of stainless steel, it is more preferable because the mechanical strength when subjected to impact force can be increased. [Explanation of Symbols]

[0090] 1...Pump body, 3...Solenoid suction valve, 35...Solenoid coil, 39...Magnetic core, 60...Coil winding section, 70...Magnetic circuit component, 100...High-pressure fuel supply pump (fuel pump), 301...First yoke section (yoke), 302...Second yoke section (yoke), 304...Fixed core, 305...Bobbin, 307...Ring (connecting member, predetermined part), D1...Gap (first gap), D2...Gap (second gap), F...Impact force, L1...Distance (first distance), L2...Distance (second distance), P...Center of rotation

Claims

1. A coil winding section formed by winding an electromagnetic coil onto a bobbin, The magnetic circuit component is a magnetic material that constitutes a magnetic circuit when current flows through the electromagnetic coil, A fuel pump equipped with an electromagnetic intake valve having, The magnetic circuit component comprises a yoke arranged to surround the coil winding, a fixed core fixed to the pump body, and a magnetic core. The coil winding portion is arranged to make a full circle around the magnetic core. The magnetic core is directly connected to the fixed core, or connected to the fixed core via a connecting member. The fixed core is welded to the magnetic core or the connecting member at the welded portion. The magnetic core is welded to the fixed core or the connecting member at the welded portion. The electromagnetic intake valve has a predetermined portion that faces the coil winding portion in the radial direction of the electromagnetic intake valve via a first gap, The magnetic core faces a portion of the yoke, and a second gap is formed between the magnetic core and the portion of the yoke. The second gap is formed at a position further away from the first gap than the first gap when an impact force is applied to the yoke or coil winding portion from the radially outer to the inner direction of the electromagnetic intake valve, with respect to the center of rotation from which the yoke or coil winding portion rotates. When the first gap is D1, the second gap is D2, the distance from the center of rotation to the first gap is L1, and the distance from the center of rotation to the second gap is L2, D2 / L2>D1 / L1 Satisfying the relationship, When an impact force is applied to the yoke or the coil winding portion of the electromagnetic intake valve from the radially outer to the inner direction, the coil winding portion and the predetermined portion first come into contact. Fuel pump.

2. The first gap is formed by the bobbin. The fuel pump according to claim 1.

3. A portion of the yoke is held so as to be displaceable in the radial direction of the electromagnetic intake valve and in the central axis direction of the electromagnetic intake valve. The fuel pump according to claim 1.

4. The predetermined portion is formed by the connecting member, The connecting member is made of a non-magnetic material. The fuel pump according to claim 1.

5. The connecting member is made of stainless steel. The fuel pump according to claim 4.

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