Solenoid valve mechanism and fuel pump

Abstract

The present invention suppresses abrasion of a rod or a component where the rod contacts. An electromagnetic suction valve mechanism (electromagnetic valve mechanism) is provided with a suction valve (valve body), a rod engaging with the suction valve, and a magnetic attraction force generation part that generates a magnetic attraction force for moving the rod in an axial direction. The rod is provided with a low friction part. The low friction part is set to have such a frictional coefficient that a frictional force generated between the rod and a rod contact component where the rod contacts becomes smaller than a rotational propulsive force of the rod.

Description

Technical Field

[0001] The present invention relates to a solenoid valve mechanism and a fuel pump provided with the solenoid valve mechanism.

Background Art

[0002] As a solenoid valve mechanism of a fuel pump, for example, it is described in Patent Document 1. The solenoid valve mechanism (solenoid draft) described in Patent Document 1 press-fits a rubber material into a housing portion provided in a fixed core. The rubber material buffers the impact caused by the cavitation collapse occurring in the fixed core. As a result, the occurrence of cavitation erosion is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the solenoid valve mechanism described in Patent Document 1, the housing portion of the fixed core formed of a metal material is filled with fuel. Therefore, cavitation erosion could not be suppressed in the entire housing portion of the fixed core.

[0005] An object of the present invention is to provide a solenoid valve mechanism and a fuel pump capable of suppressing cavitation erosion occurring in a fixed core in consideration of the above problems.

Means for Solving the Problems

[0006] To solve the above problems and achieve the objectives of the present invention, the solenoid valve mechanism of the present invention comprises a valve body, a rod that engages with the valve body, a movable core that engages with the rod, a fixed core that generates a magnetic attractive force between itself and the movable core, and a rod biasing spring that biases the rod away from the fixed core. The fixed core has a first recess having a bottom surface against which one end of the rod biasing spring abuts, a second recess formed on the bottom surface of the first recess, and an elastic member housed in the second recess. The elastic member covers the entire inner wall surface of the second recess.

[0007] Furthermore, the fuel pump of the present invention comprises a body equipped with a pressurizing chamber, a plunger supported by the body so as to be able to reciprocate, which increases or decreases the volume of the pressurizing chamber by reciprocating motion, and the above-mentioned solenoid valve mechanism for discharging fuel into the pressurizing chamber. [Effects of the Invention]

[0008] The solenoid valve mechanism and fuel pump configured as described above can suppress cavitation erosion that occurs in the fixed core. Furthermore, issues, configurations, and effects other than those 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 high-pressure fuel supply pump according to the first embodiment of the present invention. [Figure 2] This is a longitudinal cross-sectional view of a high-pressure fuel supply pump according to the first embodiment of the present invention. [Figure 3] This is a horizontal cross-sectional view of a high-pressure fuel supply pump according to the first embodiment of the present invention, as seen from above. [Figure 4] This is a longitudinal cross-sectional view of a high-pressure fuel supply pump according to the first embodiment of the present invention, viewed from a different direction than that shown in Figure 2. [Figure 5] This is a longitudinal cross-sectional view of a solenoid valve mechanism according to the first embodiment of the present invention. [Figure 6] Figures A and B show the mechanism by which cavitation erosion occurs in the recess of the fixed core when the fixed core and the movable core come into contact. [Figure 7] Figures A and B show the mechanism by which cavitation erosion occurs in the recess of the fixed core when the fixed core and the movable core come into contact. [Figure 8] Figures A and B show the mechanism by which cavitation erosion occurs in the recess of the fixed core when the fixed core and the movable core are separated. [Figure 9] Figures A and B show the mechanism by which cavitation erosion occurs in the recess of the fixed core when the fixed core and the movable core are separated. [Figure 10] Figures A and B show a conceptual diagram of a vibrating cavitation testing apparatus and the test results. [Figure 11] This is an enlarged longitudinal cross-sectional view of the fixed core of the solenoid valve mechanism according to the first embodiment of the present invention. [Figure 12] This is an enlarged longitudinal cross-sectional view of the fixed core of the solenoid valve mechanism according to the second embodiment of the present invention. [Figure 13] This is an enlarged longitudinal cross-sectional view of the fixed core of the solenoid valve mechanism according to the third embodiment of the present invention. [Figure 14] This is an enlarged longitudinal cross-sectional view of the fixed core of the solenoid valve mechanism according to the fourth embodiment of the present invention. [Modes for carrying out the invention]

[0010] 1. First Embodiment The solenoid valve mechanism and high-pressure fuel supply pump according to the first embodiment of the present invention will be described below. In each figure, common components are denoted by the same reference numerals.

[0011] [Fuel supply system] First, a fuel supply system using the high-pressure fuel supply pump (fuel pump) according to this embodiment will be explained with reference to Figure 1. Figure 1 is an overall diagram of the fuel supply system using the high-pressure fuel supply pump according to this embodiment.

[0012] As shown in FIG. 1, the fuel supply system includes a high-pressure fuel supply pump (fuel pump) 100, an ECU (Engine Control Unit) 101, a fuel tank 103, a common rail 106, and a plurality of injectors 107. The components of the high-pressure fuel supply pump 100 are integrally incorporated into a pump body 1 (hereinafter referred to as "body 1").

[0013] The fuel in the fuel tank 103 is pumped up by a feed pump 102 driven based on a signal from the ECU 101. The pumped-up fuel is pressurized to an appropriate pressure by a pressure regulator (not shown) and sent through a low-pressure pipe 104 to the low-pressure fuel inlet 51 of the high-pressure fuel supply pump 100.

[0014] The high-pressure fuel supply pump 100 pressurizes the fuel supplied from the fuel tank 103 and pumps it to the common rail 106. A plurality of injectors 107 and a fuel pressure sensor 105 are attached to the common rail 106.

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

[0016] The fuel pressure sensor 105 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 (e.g., crank rotation angle, throttle opening, engine speed, fuel pressure, etc.) obtained from various sensors.

[0017] The ECU 101 controls the operation of the high-pressure fuel supply pump 100 and multiple injectors 107 based on calculation results such as fuel pressure (target fuel pressure). Specifically, the ECU 101 has a pump control unit that controls the high-pressure fuel supply pump 100 and an injector control unit that controls the injectors 107.

[0018] The high-pressure fuel supply pump 100 includes a pressure pulsation reduction mechanism 9, a variable-capacity electromagnetic intake valve mechanism (solenoid valve mechanism) 3, a relief valve mechanism 4 (see Figure 2), and a discharge valve mechanism 8. Fuel flowing in from the low-pressure fuel inlet 51 reaches the intake port 31b of the electromagnetic intake valve mechanism 3 via the pressure pulsation reduction mechanism 9 and the intake passage 10b.

[0019] Fuel flowing into the electromagnetic intake valve mechanism 3 passes through the intake valve 32, flows through the intake passage 1a formed in the body 1, and then flows into the pressurizing chamber 11. A plunger 2 is slidably held in the pressurizing chamber 11. The plunger 2 reciprocates under power transmitted by the engine's cam 91 (see Figure 2).

[0020] In the pressurized chamber 11, fuel is drawn in from the electromagnetic intake valve mechanism 3 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke. When the fuel pressure in the pressurized chamber 11 exceeds a predetermined value, the discharge valve mechanism 8 opens, and high-pressure fuel is pumped to the common rail 106 via the fuel discharge port 12a. The discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve mechanism 3. The opening and closing of the electromagnetic intake valve mechanism 3 is controlled by the ECU 101.

[0021] [High-pressure fuel supply pump] Next, the configuration of the high-pressure fuel supply pump 100 will be explained using Figures 2 to 4. Figure 2 is a longitudinal cross-sectional view of the high-pressure fuel supply pump 100. Figure 3 is a horizontal cross-sectional view of the high-pressure fuel supply pump 100, viewed in a cross-section perpendicular to the vertical direction. Figure 4 is a longitudinal cross-sectional view of the high-pressure fuel supply pump 100, viewed from a different direction than in Figure 2.

[0022] As shown in Figures 2 and 3, the body 1 of the high-pressure fuel supply pump 100 is provided with the aforementioned intake passage 1a and a mounting flange 1b (see Figure 3). The mounting flange 1b is in close contact with the fuel pump mounting portion 90 of the engine (internal combustion engine). The mounting flange 1b is fixed to the fuel pump mounting portion 90 by a number of bolts (screws) not shown. In other words, the high-pressure fuel supply pump 100 is fixed to the fuel pump mounting portion 90 by the mounting flange 1b.

[0023] As shown in Figures 2 and 4, an O-ring 93, which is a specific example of a seat material, is interposed between the fuel pump mounting portion 90 and the body 1. This O-ring 93 prevents engine oil from leaking outside the engine (internal combustion engine) through the gap between the fuel pump mounting portion 90 and the body 1.

[0024] Furthermore, a cylinder 6 is attached to the body 1 of the high-pressure fuel supply pump 100 to guide the reciprocating motion of the plunger 2. The cylinder 6 is formed in a cylindrical shape. The outer circumference of the cylinder 6 is press-fitted into a cylinder housing recess provided in the body 1. The body 1 and cylinder 6, together with the electromagnetic intake valve mechanism 3, the plunger 2, and the discharge valve mechanism 8 (see Figure 3), form a pressurized chamber 11.

[0025] The body 1 is provided with a fixing portion 1c that engages with the axial center of the cylinder 6. The fixing portion 1c of the body 1 presses the cylinder 6 upward (upward in Figure 2). This prevents the pressurized fuel in the pressurizing chamber 11 from leaking from between the upper end surface of the cylinder 6 and the body 1.

[0026] A tappet 92 is provided at the lower end of the plunger 2. The tappet 92 converts the rotational motion of the cam 91, which is attached to the engine's camshaft, into vertical motion and transmits it to the plunger 2. The plunger 2 is biased toward the cam 91 by a spring 16 via a retainer 15. As a result, the lower end of the plunger 2 is pressed against the tappet 92. The tappet 92 reciprocates in conjunction with the rotation of the cam 91. The plunger 2 reciprocates together with the tappet 92, changing the volume of the pressurizing chamber 11.

[0027] A seal holder 17 is positioned between the cylinder 6 and the retainer 15. The seal holder 17 is formed in a cylindrical shape into which the plunger 2 is inserted. A sub-chamber 17a is formed between the upper part of the seal holder 17 and the pump body 1. The seal holder 17 also holds a plunger seal 18 at its lower end, which is on the retainer 15 side.

[0028] The plunger seal 18 is in slidable contact with the outer circumference of the plunger 2. When the plunger 2 reciprocates, the plunger seal 18 seals the fuel in the sub-chamber 17a, preventing the fuel from 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 body 1.

[0029] In Figure 2, the plunger 2 reciprocates vertically. 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.

[0030] The plunger 2 has a large diameter section 2a and a small diameter section 2b. When the plunger 2 reciprocates, the large diameter section 2a and the small diameter section 2b are located in the sub-chamber 17a. Therefore, the volume of the sub-chamber 17a increases or decreases due to the reciprocating motion of the plunger 2.

[0031] The sub-chamber 17a is in communication with the low-pressure fuel chamber 10 via the fuel passage 10c (see Figure 3). When the plunger 2 descends, fuel flows from the sub-chamber 17a to the low-pressure fuel chamber 10. When the plunger 2 rises, fuel flows from the low-pressure fuel chamber 10 to 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. As a result, pressure pulsations generated inside the high-pressure fuel supply pump 100 can be reduced.

[0032] As shown in Figures 3 and 4, an intake joint 5 is attached to the side of the body 1. The intake joint 5 is connected to a low-pressure pipe 104 (see Figure 1) through which fuel supplied from the fuel tank 103 passes. Fuel from the fuel tank 103 is supplied to the inside of the high-pressure fuel supply pump 100 from the intake joint 5.

[0033] 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. As shown in Figure 4, an intake filter 53 is located in the fuel passage communicating with the intake passage 52. The intake filter 53 removes foreign matter present in the fuel and prevents foreign matter from entering the high-pressure fuel supply pump 100. The fuel that has passed through the intake passage 52 reaches the intake port 31b (see Figure 2) of the electromagnetic intake valve mechanism 3 via the pressure pulsation reduction mechanism 9 and intake passage 10b (see Figure 2) provided in the low-pressure fuel chamber 10.

[0034] As shown in Figure 2, the body 1 of the high-pressure fuel supply pump 100 is provided with a low-pressure fuel chamber 10. The low-pressure fuel chamber 10 is covered by a damper cover 14. The low-pressure fuel chamber 10 is provided with a low-pressure fuel passage 10a and an intake passage 10b. The intake passage 10b is in communication with the intake port 31b (see Figure 2) of the electromagnetic intake valve mechanism 3. Fuel that has passed through the low-pressure fuel passage 10a reaches the intake port 31b of the electromagnetic intake valve mechanism 3 via the intake passage 10b.

[0035] 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 (see Figure 2) through the open electromagnetic intake valve mechanism 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.

[0036] The pressure pulsation reduction mechanism 9 has a metal diaphragm damper made by bonding two corrugated disc-shaped metal plates together at their outer circumference. An inert gas such as argon is injected into the metal diaphragm damper. The metal diaphragm damper absorbs or reduces pressure pulsations by expanding and contracting.

[0037] As shown in Figure 3, the discharge valve mechanism 8 is connected to the outlet side of the pressurizing chamber 11. The discharge valve mechanism 8 is housed in a discharge valve chamber 1d formed in the body 1. The discharge valve mechanism 8 includes a discharge valve seat member 81 and a discharge valve 82 that moves toward and away from the discharge valve seat member 81. The discharge valve mechanism 8 also includes a discharge valve spring 83 that biases the discharge valve 82 toward the discharge valve seat member 81 and a discharge valve stopper 84 that determines the lift amount (travel distance) of the discharge valve 82. The discharge valve stopper 84 and the body 1 are joined by welding at a contact portion 85.

[0038] The discharge valve chamber 1d is a roughly cylindrical space extending horizontally. One end of the discharge valve chamber 1d communicates with the pressurizing chamber 11. The other end of the discharge valve chamber 1d opens to the side of the body 1. The opening at the other end of the discharge valve chamber 1d is sealed by a discharge valve stopper 84.

[0039] A discharge joint 12 is joined to the body 1 by a welded joint 12b. The discharge joint 12 has a fuel outlet 12a. The fuel outlet 12a communicates with the discharge valve chamber 1d via a discharge passage 1f. The discharge passage 1f extends horizontally inside the body 1. The fuel outlet 12a is connected to a common rail 106 (see Figure 1).

[0040] When the fuel pressure in the pressurizing chamber 11 is lower than the fuel pressure in the discharge valve chamber 1d, the discharge valve 82 is pressed against the discharge valve seat member 81 by the differential pressure acting on the discharge valve 82 and the biasing force of the discharge valve spring 83. As a result, the discharge valve mechanism 8 is in a closed state. On the other hand, when the fuel pressure in the pressurizing chamber 11 becomes greater than the fuel pressure in the discharge valve chamber 1d, and the differential pressure acting on the discharge valve 82 becomes greater than the biasing force of the discharge valve spring 83, the discharge valve 82 separates from the discharge valve seat member 81. As a result, the discharge valve mechanism 8 is in an open state.

[0041] When the discharge valve mechanism 8 is open, the fuel in the pressurized chamber 11 is discharged to the common rail 106 (see Figure 1) via the discharge valve chamber 1d, the discharge passage 1f, and the fuel discharge port 12a of the discharge joint 12. With this configuration, the discharge valve mechanism 8 functions as a check valve that restricts the direction of fuel flow.

[0042] As shown in Figures 2 and 3, the body 1 is provided with a relief valve mechanism 4 that communicates with the pressurizing chamber 11. The relief valve mechanism 4 includes a relief spring 41, a relief valve holder 42, a relief valve 43, a seat member 44, and a spring support member 45.

[0043] The seat member 44 is formed in a bottomed cylindrical shape. The seat member 44 encloses a relief spring 41, a relief valve holder 42, a relief valve 43, and a support member 45. The support member 45 is located on the side of the pressurizing chamber 11. The bottom of the seat member 44 is located on the opposite side from the pressurizing chamber 11. A through hole, which serves as a fuel passage, is formed in the bottom of the seat member 44.

[0044] One end of the relief spring 41 is in contact with the spring support member 45. The other end of the relief spring 41 is in contact with the relief valve holder 42. The relief spring 41 biases the relief valve holder 42 toward the bottom of the seat member 44. The relief valve 43 is positioned between the relief valve holder 42 and the bottom of the seat member 44.

[0045] The relief valve 43 is engaged with the relief valve holder 42. The relief valve 43 is biased toward the bottom side of the seat member 44 together with the relief valve holder 42. As a result, the relief valve 43 blocks the fuel passage of the seat member 44. The fuel passage of the seat member 44 is in communication with the discharge passage 1f (see Figure 3). The movement of fuel between the pressurizing chamber 11 (upstream side) and the seat member 44 (downstream side) is blocked by the relief valve 43 contacting (tightly sealing) the seat member 44.

[0046] When the fuel pressure in the common rail 106 and the components beyond it increases, the fuel on the seat member 44 side presses against the relief valve 43. This causes the relief valve 43 to move against the biasing force of the relief spring 41. As a result, the relief valve mechanism 4 opens, and the fuel in the discharge passage 1f returns to the pressurized chamber 11 through the fuel passage of the seat member 44. Therefore, the pressure required to open the relief valve 43 is determined by the biasing force of the relief spring 41.

[0047] In this embodiment, the relief valve mechanism 4 is in communication with the pressurizing chamber 11, but it is not limited to this. The relief valve mechanism according to the present invention may be configured to communicate with a low-pressure passage (such as a low-pressure fuel inlet 51 or an intake passage 10b).

[0048] [Electromagnetic intake valve mechanism] Next, the electromagnetic intake valve mechanism 3 will be explained with reference to Figure 5. Figure 5 is an enlarged longitudinal cross-sectional view of the electromagnetic intake valve mechanism 3 of the high-pressure fuel supply pump 100, showing the open state of the electromagnetic intake valve mechanism 3.

[0049] As shown in Figure 5, the electromagnetic intake valve mechanism 3 is inserted into a lateral hole formed in the body 1. The electromagnetic intake valve mechanism 3 includes an intake valve seat 31 pressed into the lateral hole formed in the body 1, an intake valve 32, a rod 33, a rod biasing spring 34, an electromagnetic coil 35, and an anchor 36. The intake valve 32 shows one specific example of a valve body according to the present invention. The anchor 36 shows one specific example of a movable core according to the present invention.

[0050] 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 formed in the intake valve seat 31, extending from the outer circumference to the inner circumference. The intake port 31b communicates with the intake passage 10b in the low-pressure fuel chamber 10 described above.

[0051] The intake valve seat 31 has a rod guide 31c through which the rod 33 passes. The rod guide 31c is formed in a cylindrical shape. In addition to the cylindrical hole through which the rod 33 passes, the rod guide 31c is provided with a communication passage 31d that passes through in the axial direction. This prevents the movement of fuel within the electromagnetic intake valve mechanism 3 from being obstructed when the anchor 36 moves in the axial direction.

[0052] A stopper 37 is positioned in a lateral hole formed in the body 1, facing the seating portion 31a of the intake valve seat 31. The intake valve 32 is positioned between the stopper 37 and the seating portion 31a. A valve biasing spring 38 is interposed between the stopper 37 and the intake valve 32. The valve biasing spring 38 biases the intake valve 32 toward the seating portion 31a.

[0053] The suction valve 32 closes the communication between the suction port 31b and the pressurized chamber 11 by contacting the seat portion 31a. As a result, the electromagnetic suction valve mechanism 3 enters a closed state. On the other hand, the suction valve 32 opens the communication between the suction port 31b and the pressurized chamber 11 by contacting the stopper 37. As a result, the electromagnetic suction valve mechanism 3 enters an open state.

[0054] The rod 33 passes through the rod guide 31c and anchor 36 of the intake valve seat 31. The rod 33 has a rod flange 33a. The rod flange 33a engages with one end of the rod biasing spring 34. The other end of the rod biasing spring 34 engages with a fixed core 39 that surrounds the rod biasing spring 34. The rod biasing spring 34 biases the intake valve 32 in the opening direction toward the stopper 37 side via the rod 33.

[0055] The anchor 36 is formed in a substantially cylindrical shape. In addition to the cylindrical hole through which the rod 33 passes, the anchor 36 is provided with a communication passage 36a that penetrates in the axial direction. This prevents the movement of fuel within the electromagnetic intake valve mechanism 3 from being obstructed when the anchor 36 moves in the axial direction.

[0056] One end of the anchor biasing spring 40 abuts against one axial end of the anchor 36. The other axial end of the anchor 36 faces the end face of the fixed core 39. A flange contact portion is formed at the other axial end of the anchor 36, which abuts against the rod flange portion 33a of the rod 33.

[0057] The other end of the anchor biasing spring 40 is in contact with the rod guide 31c. The anchor biasing spring 40 biases the anchor 36 toward the rod flange portion 33a of the rod 33. The movable distance 36e of the anchor 36 is set to be longer than the movable distance 32e of the intake valve 32. This ensures that the intake valve 32 is reliably in contact with (seat) the seat portion 31a. As a result, the electromagnetic intake valve mechanism 3 can be reliably closed.

[0058] The fixed core 39 is formed in a bottomed cylindrical shape. That is, the fixed core 39 has a recess extending in the axial direction. The rod biasing spring 34 is inserted into the recess of the fixed core 39. The other end of the rod biasing spring 34 abuts against the bottom surface of the recess in the fixed core 39. The recess of the fixed core 39 will be explained later with reference to Figure 11.

[0059] An outer core 310 is connected to the opening of a lateral hole formed in the body 1. The outer core 310 is formed in a substantially cylindrical shape. The outer circumference of one axial end of the outer core 310 is fitted into the lateral hole formed in the body 1. The outer core 310 is fixed to the body 1 by welding.

[0060] An anchor 36 is slidably engaged with the inner circumference of the outer core 310. That is, the anchor 36 is guided by the inner circumference of the outer core 310 and moves axially (in the valve opening direction and valve closing direction). The other axial end of the outer core 310 protrudes from the body 1. A first yoke 320 is fitted onto the outer circumference of the other axial end of the outer core 310. The outer core 310 is press-fitted and fixed to the first yoke 320.

[0061] The first yoke 320 is formed in a bottomed cylindrical shape that surrounds the electromagnetic coil 35. The fixed core 39 protrudes from the opening side of the first yoke 320. A fitting hole is formed in the center of the bottom of the first yoke 320 for fitting into the outer core 310.

[0062] The opening of the first yoke 320 is closed by the second yoke 330. The second yoke 330 is made of a roughly annular plate. A circular through hole is formed in the approximate center of the second yoke 330. The fixing core 39 passes through the through hole in the second yoke 330. A fixing pin 39a is fixed to the portion of the fixing core 39 that protrudes from the second yoke 330. The fixing pin 39a biases the second yoke 330 toward the anchor 36.

[0063] The first yoke 320 and the second yoke 330 constitute a magnetic circuit. The second yoke 330 is formed from the same material as the first yoke 320. Examples of materials for the first yoke 320 and the second yoke 330 include magnetic stainless steel.

[0064] The electromagnetic coil 35 is positioned inside the first yoke 320, encircling the fixed core 39. The electromagnetic coil 35 consists of copper wire wound multiple times on a bobbin 35a. A terminal member 30 (see Figure 2) is electrically connected to the electromagnetic coil 35. Current flows through the electromagnetic coil 35 via the terminal member 30.

[0065] In the unpowered state, when no current flows through the electromagnetic coil 35, the rod 33 is biased in the valve-opening direction by the biasing force of the rod biasing spring 34, pressing the intake valve 32 in the valve-opening direction. As a result, the intake valve 32 moves away from the seat portion 31a and contacts the stopper 37, and the electromagnetic intake valve mechanism 3 is in the open state. In other words, the electromagnetic intake valve mechanism 3 is a normally open type that opens in the unpowered state.

[0066] The terminal member 30 is positioned in the recess of the connector 30a (see Figure 2). The connector 30a is molded integrally with the terminal member 30 and the electromagnetic coil 35. The connector 30a passes through the notch of the first yoke 320. The lower part of the connector 30a faces the second yoke 330. The second yoke 330 has a notch to avoid interference with the connector 30a.

[0067] A sealing ring 340 is provided on the inner circumference of the electromagnetic coil 35. The sealing ring 340 is formed in a cylindrical shape. An outer core 310 is inserted into one axial end of the sealing ring 340. A fixed core 39 is inserted into the other axial end of the sealing ring 340.

[0068] When inserted into the sealing 340, the outer surfaces of the fixed core 39 and the outer core 310 form the same circumferential surface as the outer surface of the sealing 340. This facilitates the attachment of other components, such as the bobbin 35a.

[0069] The sealant 340 is formed from a thin, deformable (expandable) material. The sealant 340 has a greater elongation rate than the fixing core 39 and anchor 36. For example, the sealant 340 has an elongation rate of 35% or more. Furthermore, the sealant 340 is nonmagnetic. As the material for the sealant 340, austenitic stainless steel is preferable, for example.

[0070] In the open state of the electromagnetic intake valve mechanism 3, fuel from the intake port 31b flows through the space between the intake valve 32 and the seating portion 31a, and into the pressurized chamber 11 through multiple fuel passage holes (not shown) in the stopper 37 and the intake passage 1a. In the open state of the electromagnetic intake valve mechanism 3, the intake valve 32 is in contact with the stopper 37, thereby restricting the position of the intake valve 32 in the opening direction. In the open state of the electromagnetic intake valve mechanism 3, the gap between the intake valve 32 and the seating portion 31a is the movable distance 32e of the intake valve 32, which is the opening stroke.

[0071] When current flows through the electromagnetic coil 35, a magnetic flux is generated. The generated magnetic flux passes through the fixed core 39, the second yoke 330, the first yoke 320, the outer core 310, and the anchor 36 as a magnetic path. Then, a magnetic attractive force acts on the magnetic attractive surfaces S of the anchor 36 and the fixed core 39. As a result, the anchor 36 moves against the biasing force of the rod biasing spring 34 and comes into contact with the fixed core 39.

[0072] When the anchor 36 moves toward the fixed core 39, in the valve-closing direction, the rod 33 that engages with the anchor 36 moves together with the anchor 36. As a result, the intake valve 32 is released from the biasing force toward the valve-opening direction and moves toward the valve-closing direction due to the biasing force of the valve biasing spring 38. When the intake valve 32 comes into contact with the seating portion 31a of the intake valve seat 31, the electromagnetic intake valve mechanism 3 enters the closed state.

[0073] [Operation of the high-pressure fuel supply pump] Next, the operation of the high-pressure fuel pump according to this embodiment will be explained using Figure 2.

[0074] In Figure 2, when the plunger 2 descends, if the electromagnetic intake valve mechanism 3 is open, fuel flows from the intake passage 1a 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, if the electromagnetic intake valve mechanism 3 is closed, the fuel in the pressurizing chamber 11 is pressurized. As a result, the fuel in the pressurizing chamber 11 is pumped through the discharge valve mechanism 8 to the common rail 106 (see Figure 1). Hereinafter, the stroke in which the plunger 2 rises will be referred to as the compression stroke.

[0075] If the electromagnetic intake valve mechanism 3 is closed during the compression stroke, the fuel drawn into the pressurizing chamber 11 during the intake stroke is pressurized and discharged to the common rail 106 side. On the other hand, if the electromagnetic intake valve mechanism 3 is open during the compression stroke, the fuel in the pressurizing chamber 11 is pushed back to the intake passage 1a side and is not discharged to the common rail 106 side. In this way, the discharge of fuel by the high-pressure fuel supply pump 100 is operated by opening and closing the electromagnetic intake valve mechanism 3. The opening and closing of the electromagnetic intake valve mechanism 3 is controlled by the ECU 101.

[0076] During the intake stroke, the volume of the pressurized chamber 11 increases, and the fuel pressure in the pressurized chamber 11 decreases. As a result, the fuel pressure in the pressurized chamber 11 becomes lower than the fuel pressure in the intake port 31b. When the biasing force due to the pressure difference between the two exceeds the biasing force of the valve biasing spring 38, the intake valve 32 separates from the seat portion 31a. This causes the electromagnetic intake valve mechanism 3 to open. Consequently, the fuel from the intake port 31b passes between the intake valve 32 and the seat portion 31a, and flows into the pressurized chamber 11 through the multiple holes provided in the stopper 37.

[0077] After the intake stroke is completed, the process moves to the compression stroke. At this time, the electromagnetic coil 35 remains unenergized, and no magnetic attractive force acts between the anchor 36 and the fixed core 39. The intake valve 32 is then subjected to a biasing force in the opening direction, corresponding to the difference in biasing forces between the anchor biasing spring 40 and the rod biasing spring 34. Furthermore, the intake valve 32 is subjected to a fluid force (pressure in the closing direction) generated when fuel flows back from the pressurized chamber 11 to the low-pressure fuel passage 10a.

[0078] In this state, in order for the electromagnetic intake valve mechanism 3 to maintain the open state, the difference in biasing force between the anchor biasing spring 40 and the rod biasing spring 34 is set to be greater than the fluid force. 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 intake valve 32 and the intake valve seat 31. Consequently, the fuel pressure inside the pressurizing chamber 11 does not rise. This process is called the return process.

[0079] During the return process, when a control signal from the ECU 101 (see Figure 1) is applied to the electromagnetic intake valve mechanism 3, current flows through the electromagnetic coil 35 via the terminal member 30. When current flows through the electromagnetic coil 35, a magnetic attractive force acts on the magnetic attraction surface S between the fixed core 39 and the anchor 36, causing the anchor 36 to be attracted to the fixed core 39.

[0080] Then, when the magnetic attraction force becomes greater than the biasing force of the rod biasing spring 34, the anchor 36 moves toward the fixed core 39 (towards the valve closing direction) against the biasing force of the rod biasing spring 34. As a result, the rod 33 that engages with the anchor 36 moves toward the intake valve 32. Consequently, the intake valve 32 seats on the seat portion 31a 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 intake valve 32 seats on the seat portion 31a, the electromagnetic intake valve mechanism 3 enters a closed state.

[0081] After the electromagnetic intake valve mechanism 3 closes, the fuel in the pressurizing chamber 11 is pressurized as the plunger 2 rises. When the fuel in the pressurizing chamber 11 reaches a predetermined pressure or higher, it passes through the discharge valve mechanism 8 and is discharged to the common rail 106 (see Figure 1). This process is called the discharge process. In other words, the compression process from the lower starting point to the upper starting point of the plunger 2 consists of a return process and a discharge process. The amount of high-pressure fuel discharged can be controlled by controlling the timing of energization to the electromagnetic coil 35 of the electromagnetic intake valve mechanism 3.

[0082] By energizing the electromagnetic coil 35 earlier, the proportion of the return stroke during the compression stroke decreases, and the proportion of the discharge stroke increases. As a result, less fuel is returned to the intake passage 10b, and more fuel is discharged at high pressure. On the other hand, by delaying the energizing timing of the electromagnetic coil 35, the proportion of the return stroke during the compression stroke increases, and the proportion of the discharge stroke decreases. As a result, more fuel is returned to the intake passage 10b, and less fuel is discharged at high pressure. In this way, by controlling the timing of energizing the electromagnetic coil 35, the amount of fuel discharged at high pressure can be controlled to the amount required by the engine (internal combustion engine).

[0083] [Cavitation erosion occurring in fixed cores] Next, cavitation erosion occurring in the recess of the fixed core 39 will be explained with reference to Figures 6 to 9.

[0084] (When the fixed core and the movable core are in contact) First, the cavitation erosion that occurs in the recess of the fixed core 39 when the fixed core 39 and the anchor 36 come into contact will be explained with reference to Figures 6 and 7. Figure 6A shows the state where the fixed core 39 and the anchor 36 are in separate positions. Figure 6B shows the moment when the anchor 36 comes into contact with the fixed core 39. Figure 7A shows the state in which cavitation occurs when the anchor 36 comes into contact with the fixed core 39. Figure 7B shows the state in which erosion occurs.

[0085] As shown in Figure 6A, when the electromagnetic coil 35 is energized, a magnetic attractive force is generated on the magnetic attraction surface S between the fixed core 39 and the anchor 36. As a result, the anchor 36 moves toward the fixed core 39 (to the left in Figure 6A).

[0086] As the anchor 36 approaches the fixed core 39, the fluid (fuel) between the anchor 36 and the fixed core 39 flows into the communication passage 36a of the anchor 36 and the recess of the fixed core 39 (hereinafter, the recess of the fixed core 39 will be referred to as the "fixed core recess"). At this time, the region V near the bottom of the fixed core recess has no escape route for the fluid. As a result, the fuel in region V becomes high pressure.

[0087] As shown in Figure 6B, when the anchor 36 moves in a direction approaching the fixed core 39, the anchor 36 collides with the fixed core 39. This stops the movement of the anchor 36, and the anchor 36 enters a contact state.

[0088] When anchor 36 stops, the inflow of fluid into the fixed core recess stops. As a result, the fluid in the fixed core recess, which had been under high pressure, flows out from the fixed core recess to the communication passage 36a side of anchor 36. Consequently, the fluid pressure in region V of the fixed core recess gradually decreases.

[0089] As shown in Figure 7A, the fluid in the recess of the fixed core continues to flow out toward the connecting passage 36a due to inertial force. As a result, the fluid pressure in region V of the recess of the fixed core continues to decrease. When the fluid pressure in region V falls below the saturated vapor pressure, cavitation C occurs in region V of the recess of the fixed core.

[0090] As shown in Figure 7B, the fluid pressure in region V where cavitation occurred subsequently recovers. This is due to pressure waves generated by the fluid flowing out of the fixed core recess colliding with surrounding components and reflecting, or the re-inflow of fluid into the fixed core recess due to a decrease in the fluid pressure within the fixed core recess.

[0091] When the fluid pressure in region V of the fixed core recess recovers, the cavitation C that has formed in region V of the fixed core recess collapses. As a result, the impact force when the cavitation collapses erodes the fixed core 39, causing erosion E to occur.

[0092] (When the fixed core and movable core are separated) Next, the cavitation erosion that occurs in the recess of the fixed core 39 when the fixed core 39 and the anchor 36 are separated will be explained with reference to Figures 8 and 9. Figure 8A shows the state in which the fixed core 39 and the anchor 36 are in contact. Figure 8B shows the state in which the anchor 36 is in the process of separating from the fixed core 39. Figure 9A shows the state in which cavitation is occurring in the state in which the anchor 36 is in the process of separating from the fixed core 39. Figure 9B shows the state in which erosion is occurring.

[0093] As shown in Figure 8A, when the anchor 36 is in contact with the fixed core 39, and before the anchor 36 separates from the fixed core 39, there is no volume change in the vicinity of the fixed core recess inside the electromagnetic intake valve mechanism 3. Therefore, there is no fluid pressure fluctuation in region V of the fixed core recess. As a result, the fluid is in a static pressure state.

[0094] As shown in Figure 8B, when the anchor 36 moves away from the fixed core 39 (to the right in Figure 8), fluid flows between the fixed core 39 and the anchor 36 from the communication passage 36a and the recess in the fixed core. As a result, the fluid pressure in region V of the recess in the fixed core decreases.

[0095] As shown in Figure 9A, if the fluid pressure in region V of the fixed core recess continues to decrease, the fluid pressure in region V will fall below the saturated vapor pressure. This causes cavitation C to occur in region V of the fixed core recess.

[0096] As shown in Figure 9B, the fluid pressure in region V where cavitation occurred subsequently recovers. This is due to a pressure wave generated when anchor 36 stops moving, or to the re-inflow of fluid into the fixed core recess due to a decrease in fluid pressure within the fixed core recess.

[0097] When the fluid pressure in region V of the fixed core recess recovers, the cavitation C that has formed in region V of the fixed core recess collapses. As a result, the impact force when the cavitation collapses erodes the fixed core 39, causing erosion E to occur.

[0098] The region V of the fixed core recess is subjected to a harsher environment for cavitation erosion as the movement speed of the anchor 36 increases. On the other hand, in recent years, there has been a demand for higher discharge pressure and larger flow rates in high-pressure fuel pumps. This necessitates a larger lift amount for the cam 91. The movement speed of the anchor 36 is qualitatively correlated with the lift amount of the cam 91. Therefore, in order to accommodate the higher discharge pressure and larger flow rates of high-pressure fuel pumps, it is necessary to improve the toughness of region V of the fixed core recess against cavitation erosion.

[0099] Furthermore, fuel diversification has been progressing in recent years. On the other hand, fuels with low saturated vapor pressure are prone to cavitation. Therefore, fuel diversification requires improved resilience against cavitation erosion.

[0100] If cavitation erosion occurs and damages the components of the electromagnetic intake valve mechanism 3, holes may form in the components, potentially leading to fuel leaks. Even if holes do not form in the components, the scraped parts may become foreign objects that cause malfunctions in the electromagnetic intake valve mechanism 3. Therefore, improved resistance to cavitation erosion is required.

[0101] [Erosion resistance of rubber materials] Next, the etching resistance of rubber materials will be explained with reference to Figure 10. Figure 10A is a conceptual diagram of a vibrating cavitation testing apparatus. Figure 10B shows the test results obtained using the vibrating cavitation testing apparatus.

[0102] The vibrating cavitation testing device generates cavitation by causing pressure fluctuations through vertical vibration of the horn 200. The test specimen 202 faces the tip 201 of the horn 200. The vibrating cavitation testing device allows for the observation of the progression of erosion due to cavitation in the test specimen 202.

[0103] The test results under certain test conditions are shown in Figure 10B. The horizontal axis of Figure 10B represents hardness (Vickers hardness), and the vertical axis represents the latency period until erosion occurs. As shown in Figure 10B, for materials with a hardness of Hv400 or higher, the latency period is approximately 40 to 60 minutes. On the other hand, the latency period for rubber materials was 120 minutes or more, confirming their excellent erosion resistance. Note that rubber materials cannot be expressed in terms of Vickers hardness. Therefore, the latency period for rubber materials is not plotted in Figure 10B.

[0104] [Fixed Core Configuration] Next, the configuration of the fixed core 39 according to the first embodiment will be described with reference to Figure 11. Figure 11 is an enlarged longitudinal cross-sectional view of the fixed core 39 according to the first embodiment.

[0105] As shown in Figure 11, the fixed core 39 comprises a fixed core body 391 and a rubber member 392 attached to the fixed core body 391. The fixed core body 391 is formed from a metal material into a bottomed cylindrical shape. The fixed core body 391 has a first recess 391a into which the rod biasing spring 34 is inserted, and a second recess 391b that opens to the bottom surface of the first recess 391a.

[0106] The first recess 391a is formed in a substantially cylindrical shape. The other end of the rod biasing spring 34, as described above, abuts against the bottom surface of the first recess 391a. The second recess 391b opens in the center of the bottom surface of the first recess 391a. The second recess 391b faces the axial hole of the rod biasing spring 34. The second recess 391b is formed in a substantially cylindrical shape.

[0107] The rubber member 392 corresponds to the elastic member according to the present invention. The rubber member 392 is formed in a substantially cylindrical shape with substantially the same diameter as the second recess 391b. The rubber member 392 is press-fitted and fixed into the second recess 391b. The rubber member 392 covers the entire inner wall surface of the second recess 391b.

[0108] The rubber member 392 is set to have approximately the same shape as the second recess 391b. The end face of the rubber member 392 on the rod biasing spring 34 side forms a coplanar plane with the bottom surface of the first recess 391a. The rubber member 392 is shaped so that it does not come into contact with the bottom surface of the first recess 391a. In other words, the rubber member 392 is not interposed between the bottom surface of the first recess 391a and the rod biasing spring 34.

[0109] The rubber member 392 is provided with a recess 392a. The recess 392a opens onto the end face of the rubber member 392 on the rod biasing spring 34 side. The recess 392a is formed in a roughly oval shape to allow for easy molding of the rubber material. Fuel enters the first recess 391a of the fixed core body 391 and the recess 392a of the rubber member 392. On the other hand, fuel does not enter the second recess 391b of the fixed core body 391.

[0110] In such an electromagnetic intake valve mechanism 3 using a fixed core 39, cavitation erosion concentrates in the recess 392a of the rubber member 392. Therefore, it is possible to suppress the occurrence of cavitation erosion on the rod biasing spring 34 side (first recess 391a) rather than on the rubber member 392 side.

[0111] Furthermore, the inner wall surface of the second recess 391b in the fixed core body 391 does not come into contact with the fuel. This suppresses the occurrence of erosion on the inner wall surface of the second recess 391b. In this way, by attaching the rubber member 392 to the second recess 391b, it is possible to suppress the occurrence of erosion in the fixed core body 391, which is made of metal.

[0112] In this embodiment, the bottom surface of the second recess 391b is formed as a flat surface. However, the bottom surface of the second recess 391b according to the present invention may be a curved or tapered surface, taking into consideration ease of processing.

[0113] 2. Second Embodiment Next, an electromagnetic intake valve mechanism according to a second embodiment of the present invention will be described with reference to Figure 12. Figure 12 is an enlarged longitudinal cross-sectional view of the fixed core according to the second embodiment.

[0114] The electromagnetic intake valve mechanism 3A according to the second embodiment has the same configuration as the electromagnetic intake valve mechanism 3 according to the first embodiment. The difference between the electromagnetic intake valve mechanism 3A and the electromagnetic intake valve mechanism 3 is the fixed core 39A. Therefore, the fixed core 39A will be described here, and the description of the configuration common to the electromagnetic intake valve mechanism 3 will be omitted.

[0115] As shown in Figure 12, the fixed core 39A has a fixed core body 391 and a rubber member 393 attached to the fixed core body 391. The fixed core body 391 is the same as in the first embodiment.

[0116] The rubber member 393 corresponds to the elastic member according to the present invention. The rubber member 393 is formed in a substantially cylindrical shape with substantially the same diameter as the second recess 391b. The rubber member 393 is press-fitted and fixed into the second recess 391b. The rubber member 393 covers the entire inner wall surface of the second recess 391b.

[0117] The rubber member 393 is set to have approximately the same shape as the second recess 391b. The end face of the rubber member 393 on the rod biasing spring 34 side forms a coplanar plane with the bottom surface of the first recess 391a. The rubber member 393 is shaped so that it does not come into contact with the bottom surface of the first recess 391a. In other words, the rubber member 393 is not interposed between the bottom surface of the first recess 391a and the rod biasing spring 34.

[0118] The rubber member 393 is provided with a recess 393a. The recess 393a opens onto the end face of the rubber member 392 on the rod biasing spring 34 side. The recess 393a is formed in a substantially cylindrical shape. The bottom surface of the recess 393a is formed as a hemispherical curved surface.

[0119] A projection 393b is formed in the center of the bottom surface of the recess 393a, projecting toward the opening. The end face of the projection 393b is located within the recess 393a. The position of the projection 393b is set considering the insertion position of the mold and nozzle for molding the rubber member 393. Thus, the rubber member according to the present invention only needs to have a recess where cavitation erosion is concentrated, and the shape of the recess can be set as appropriate.

[0120] Fuel enters the first recess 391a of the fixed core body 391 and the recess 393a of the rubber member 393. On the other hand, fuel does not enter the second recess 391b of the fixed core body 391. In an electromagnetic intake valve mechanism 3A using such a fixed core 39A, cavitation erosion concentrates in the recess 393a of the rubber member 393. Therefore, it is possible to suppress the occurrence of cavitation erosion on the rod biasing spring 34 side (first recess 391a) rather than on the rubber member 393 side.

[0121] Furthermore, the inner wall surface of the second recess 391b in the fixed core body 391 does not come into contact with the fuel. This suppresses the occurrence of erosion on the inner wall surface of the second recess 391b. In this way, by attaching the rubber member 393 to the second recess 391b, it is possible to suppress the occurrence of erosion on the fixed core body 391, which is made of metal.

[0122] 3. Third Embodiment Next, an electromagnetic intake valve mechanism according to a third embodiment of the present invention will be described with reference to Figure 13. Figure 13 is an enlarged longitudinal cross-sectional view of the fixed core according to the third embodiment.

[0123] The electromagnetic intake valve mechanism 3B according to the third embodiment has the same configuration as the electromagnetic intake valve mechanism 3 according to the first embodiment. The difference between the electromagnetic intake valve mechanism 3B and the electromagnetic intake valve mechanism 3 is the fixed core 39B. Therefore, the fixed core 39B will be described here, and the description of the configuration common to the electromagnetic intake valve mechanism 3 will be omitted.

[0124] As shown in Figure 13, the fixed core 39B comprises a fixed core body 394 and a rubber member 395 attached to the fixed core body 394. The fixed core body 394 is formed from a metal material into a bottomed cylindrical shape. The fixed core body 394 has a first recess 394a into which the rod biasing spring 34 is inserted, a second recess 394b opening to the bottom surface of the first recess 394a, and a communication port 394c opening to the bottom surface of the second recess 394b.

[0125] The first recess 394a is formed in a substantially cylindrical shape. The other end of the rod biasing spring 34, as described above, abuts against the bottom surface of the first recess 394a. The second recess 394b opens in the center of the bottom surface of the first recess 394a. The second recess 394b faces the axial hole of the rod biasing spring 34. The second recess 394b is formed in a substantially cylindrical shape. The communication opening 394c extends to the bottom end surface of the fixed core body 394.

[0126] The rubber member 395 corresponds to the elastic member according to the present invention. The rubber member 395 is integrally molded (for example, by insert molding) with the fixed core body 394. When molding the fixed core 39B, the rubber material is injected from the communication opening 394c toward the second recess 394b. This prevents interference between the nozzle that injects the rubber material and the fixed core body 394. As a result, the molding of the rubber member 395 can be easily performed.

[0127] The rubber member 395 fills the second recess 394b and the communication opening 394c. Therefore, the rubber member 395 covers the entire inner wall surface of the second recess 394b and the inner wall surface of the communication opening 394c.

[0128] The rubber member 395 is set to have substantially the same shape as the second recess 394b and the communication opening 394c. The end face of the rubber member 395 on the rod biasing spring 34 side forms a plane with the bottom surface of the first recess 394a. The rubber member 395 is shaped so that it does not come into contact with the bottom surface of the first recess 394a. In other words, the rubber member 395 is not interposed between the bottom surface of the first recess 394a and the rod biasing spring 34.

[0129] The rubber member 395 is provided with a recess 395a. The recess 395a opens onto the end face of the rubber member 395 on the rod biasing spring 34 side. The recess 395a is formed in a roughly oval shape to allow for easy molding of the rubber material. Fuel enters the first recess 394a of the fixed core body 394 and the recess 395a of the rubber member 395. On the other hand, fuel does not enter the second recess 394b of the fixed core body 394 and the communication port 394c.

[0130] In an electromagnetic intake valve mechanism 3B using such a fixed core 39B, cavitation erosion concentrates in the recess 395a of the rubber member 395. Therefore, it is possible to suppress the occurrence of cavitation erosion on the rod biasing spring 34 side (first recess 394a) rather than on the rubber member 395 side.

[0131] Furthermore, the inner wall surface of the second recess 394b in the fixed core body 394 does not come into contact with the fuel. This suppresses the occurrence of erosion on the inner wall surface of the second recess 394b. In this way, by attaching the rubber member 395 to the second recess 394b, it is possible to suppress the occurrence of erosion on the fixed core body 394, which is made of metal.

[0132] 4. Fourth Embodiment Next, an electromagnetic intake valve mechanism according to the fourth embodiment of the present invention will be described with reference to Figure 14. Figure 14 is an enlarged longitudinal cross-sectional view of the fixed core according to the fourth embodiment.

[0133] The electromagnetic intake valve mechanism 3C according to the fourth embodiment has the same configuration as the electromagnetic intake valve mechanism 3 according to the first embodiment. The difference between the electromagnetic intake valve mechanism 3C and the electromagnetic intake valve mechanism 3 is the fixed core 39C. Therefore, the fixed core 39C will be described here, and the description of the configuration common to the electromagnetic intake valve mechanism 3 will be omitted.

[0134] As shown in Figure 14, the fixed core 39C has a fixed core body 396 and a rubber member 397 attached to the fixed core body 396. The fixed core body 396 is formed from a metal material into a bottomed cylindrical shape. The fixed core body 396 has a first recess 396a into which the rod biasing spring 34 is inserted, a second recess 396b opening to the bottom surface of the first recess 396a, and a communication opening 396c opening to the bottom surface of the second recess 396b.

[0135] The first recess 396a is formed in a substantially cylindrical shape. The other end of the rod biasing spring 34, as described above, abuts against the bottom surface of the first recess 396a. The second recess 396b opens in the center of the bottom surface of the first recess 396a. The second recess 396b faces the axial hole of the rod biasing spring 34. The second recess 396b is formed in a substantially cylindrical shape.

[0136] The communication opening 396c extends to the bottom end face of the fixed core body 394. The communication opening 396c has a shape in which two cylinders of different diameters are aligned in the axial direction. The communication opening 396c has a large-diameter portion that opens to the bottom side of the fixed core body 394 and a small-diameter portion that communicates with the large-diameter portion and the second recess 396b. The large-diameter portion has a larger diameter than the small-diameter portion.

[0137] The rubber member 397 corresponds to the elastic member according to the present invention. The rubber member 397 is integrally molded (for example, by insert molding) with the fixed core body 396. When molding the fixed core 39C, the rubber material is injected from the communication opening 396c toward the second recess 396b. This prevents interference between the nozzle for injecting the rubber material and the fixed core body 394. As a result, the molding of the rubber member 397 can be easily performed.

[0138] Furthermore, the larger diameter portion of the communication port 396c, which is the inlet side (opposite the second recess 396b), is a larger space than the smaller diameter portion, which is the second recess 396b side. Therefore, it can accommodate various sizes of nozzles for injecting rubber material.

[0139] The rubber member 397 fills the second recess 396b and the communication opening 396c. Therefore, the rubber member 397 covers the entire inner wall surface of the second recess 396b and the inner wall surface of the communication opening 396c.

[0140] The rubber member 397 is set to have substantially the same shape as the second recess 396b and the communication opening 396c. The end face of the rubber member 397 on the rod biasing spring 34 side forms a plane with the bottom surface of the first recess 396a. The rubber member 397 is shaped so that it does not come into contact with the bottom surface of the first recess 396a. In other words, the rubber member 397 is not interposed between the bottom surface of the first recess 396a and the rod biasing spring 34.

[0141] The rubber member 397 is provided with a recess 397a. The recess 397a opens onto the end face of the rubber member 397 on the rod biasing spring 34 side. The recess 397a is formed in a roughly oval shape to allow for easy molding of the rubber material. Fuel enters the first recess 396a of the fixed core body 396 and the recess 397a of the rubber member 397. On the other hand, fuel does not enter the second recess 396b of the fixed core body 396 and the communication port 396c.

[0142] In an electromagnetic intake valve mechanism 3C using such a fixed core 39C, cavitation erosion concentrates in the recess 397a of the rubber member 397. Therefore, it is possible to suppress the occurrence of cavitation erosion on the rod biasing spring 34 side (first recess 394a) rather than on the rubber member 397 side.

[0143] Furthermore, the inner wall surface of the second recess 396b in the fixed core body 396 does not come into contact with the fuel. This suppresses the occurrence of erosion on the inner wall surface of the second recess 396b. In this way, by attaching the rubber member 397 to the second recess 396b, it is possible to suppress the occurrence of erosion in the fixed core body 396, which is made of metal.

[0144] 5. Summary As described above, the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) comprises an intake valve 32 (valve body), a rod 33 that engages with the intake valve 32, and an anchor 36 (movable core) with which the rod 33 engages. Furthermore, the electromagnetic intake valve mechanism 3 comprises a fixed core 39 that generates a magnetic attractive force between itself and the anchor 36, and a rod biasing spring 34 that biases the rod 33 away from the fixed core 39. The fixed core 39 has a first recess 391a having a bottom surface against which one end of the rod biasing spring 34 abuts, a second recess 391b formed on the bottom surface of the first recess 391a, and a rubber member 392 (elastic member) housed in the second recess 391b. The rubber member 392 covers the entire inner wall surface of the second recess 391b. This prevents fuel from entering the second recess 391b of the fixed core 39. As a result, erosion on the inner wall surface of the second recess 391b can be suppressed.

[0145] The rubber member 392 (elastic member) of the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) described above has a recess 392a on the surface that comes into contact with the fuel. As a result, cavitation erosion concentrates in the recess 392a of the rubber member 392. Therefore, it is possible to suppress the occurrence of cavitation erosion in the first recess 391a, which is located on the rod biasing spring 34 side of the rubber member 392.

[0146] The rubber member 392 (elastic member) of the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) described above may protrude from the bottom surface of the first recess 391a toward the rod biasing spring 34. This allows the axial dimension of the rubber member 392 to be longer than the depth of the second recess 391b. As a result, the minimum allowable dimension of the rubber member 392 can be set to the depth of the second recess 391b, making it easier to manufacture the rubber member 392.

[0147] The rubber member 395 (elastic member) of the electromagnetic intake valve mechanism 3B (solenoid valve mechanism) described above is filled into the second recess 394b and fixed or bonded to the second recess 394b. This makes it easy to form a rubber member 395 that covers the entire inner wall surface of the second recess 394b.

[0148] The rubber member 392 (elastic member) of the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) described above is shaped so as not to come into contact with the bottom surface of the first recess 391a. This prevents the rubber member 392 from being interposed between the bottom surface of the first recess 391a and the rod biasing spring 34. As a result, the compressed length of the rod biasing spring 34 can be prevented from becoming shorter than the set length. Therefore, the rod biasing spring 34 can bias the anchor 36 with an appropriate biasing force.

[0149] The rubber member 392 (elastic member) of the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) described above is shaped so that it is not interposed between the bottom surface of the first recess 391a and the rod biasing spring 34. This prevents the compressed length of the rod biasing spring 34 from becoming shorter than the set length. As a result, the rod biasing spring 34 can bias the anchor 36 with the appropriate biasing force.

[0150] The high-pressure fuel supply pump 100 (fuel pump) described above comprises a body 1 equipped with a pressurizing chamber 11, a plunger 2 supported by the body 1 so as to be able to reciprocate and which increases or decreases the volume of the pressurizing chamber 11 by reciprocating motion, and the electromagnetic intake valve mechanism 3 (solenoid valve mechanism) described above which discharges fuel into the pressurizing chamber 11. As a result, fuel does not enter the second recess 391b of the fixed core 39 in the electromagnetic intake valve mechanism 3. Consequently, erosion on the inner wall surface of the second recess 391b can be suppressed.

[0151] The embodiments of the solenoid valve mechanism and fuel pump of the present invention, including their effects, have been described above. However, the solenoid valve mechanism and fuel pump of the present invention are not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention as described in the claims.

[0152] Furthermore, the embodiments described above are explained in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those comprising all the described configurations. It is also possible to replace parts of the configuration of one embodiment with those of another embodiment, and to add configurations from other embodiments to the configuration of one embodiment. Additionally, it is possible to add, delete, or replace parts of the configuration of each embodiment with those of other embodiments.

[0153] For example, in the first and second embodiments described above, the rubber members 392 and 393 were press-fitted and fixed into the second recess 391b. However, the rubber member (elastic member) according to the present invention may be bonded to the inner wall surface of the second recess using an adhesive.

[0154] In the embodiments described above, rubber members 392, 393, 395, and 397 were used as the elastic members according to the present invention. However, the elastic members according to the present invention are not limited to rubber members; any material that can buffer shock waves caused by cavitation collapse can be appropriately selected. Preferably, the elastic members according to the present invention are members with a Poisson's ratio of 0.45 or more and 0.55 or less. [Explanation of Symbols]

[0155] 1...Body, 2...Plunger, 3,3A,3B,3C...Solenoid intake valve mechanism (solenoid valve mechanism), 4...Relief valve mechanism, 5...Intake joint, 6...Cylinder, 8...Discharge valve mechanism, 9...Pressure pulsation reduction mechanism, 10...Low-pressure fuel chamber, 11...Pressurizing chamber, 12...Discharge joint, 14...Damper cover, 15...Retainer, 17...Seal holder, 18...Plunger seal, 30...Terminal member, 31...Intake valve seat, 31a...Seating part, 31b...Intake port, 31c...Rod guide, 31d...Connecting passage, 32...Intake valve, 33...Rod, 33a...Rod flange, 35...Solenoid coil, 35a...Bobbin, 36...Anchor (movable core), 36a...Connecting passage, 37...Stopper 39, 39A, 39B, 39C…Fixed core, 39a…Fixed pin, 51…Low-pressure fuel intake, 52…Intake passage, 53…Intake filter, 90…Fuel pump mounting section, 91…Cam, 92…Tappet, 93…O-ring, 100…High-pressure fuel supply pump, 101…ECU, 102…Feed pump, 103…Fuel tank, 104…Low-pressure piping, 105…Fuel pressure sensor, 106…Common rail, 107…Injector, 200…Horn, 201…Tip, 202…Test piece, 310…Outer core, 320…First yoke, 330…Second yoke, 340…Sealing, 391, 394, 396…Fixed core body, 391a, 394a, 396a…First recess, 391b, 394b, 396b... Second recess, 392, 393, 395, 397... Rubber member, 392a, 393a, 395a, 397a... Recess, 393b... Protrusion, 394c, 396c... Communication opening

Claims

1. In a solenoid valve mechanism comprising a valve body, a rod that engages with the valve body, a movable core that engages with the rod, a fixed core that generates a magnetic attractive force between itself and the movable core, and a rod biasing spring that biases the rod away from the fixed core, The fixed core has a first recess having a bottom surface against which one end of the rod biasing spring abuts, a second recess formed on the bottom surface of the first recess, and an elastic member housed in the second recess. The elastic member covers the entire inner wall surface of the second recess. Solenoid valve mechanism.

2. The elastic member has a recess on the surface that comes into contact with the fuel. The solenoid valve mechanism according to claim 1.

3. The elastic member protrudes from the bottom surface of the first recess toward the rod biasing spring. The solenoid valve mechanism according to claim 1.

4. The elastic member is filled into the second recess and fixed or bonded to the second recess. The solenoid valve mechanism according to claim 1.

5. The elastic member has a shape that does not contact the bottom surface of the first recess. The solenoid valve mechanism according to claim 1.

6. The elastic member is shaped so that it is not interposed between the bottom surface of the first recess and the rod biasing spring. The solenoid valve mechanism according to claim 1.

7. A body equipped with a pressurized chamber, A plunger is supported on the body so as to be able to reciprocate, and the volume of the pressurizing chamber is increased or decreased by the reciprocating motion, The system includes a solenoid valve mechanism for discharging fuel into the pressurized chamber, The solenoid valve mechanism is The valve comprises a valve body, a rod that engages with the valve body, a movable core that engages with the rod, a fixed core that generates a magnetic attractive force between itself and the movable core, and a rod biasing spring that biases the rod away from the fixed core. The fixed core has a first recess having a bottom surface against which one end of the rod biasing spring abuts, a second recess formed on the bottom surface of the first recess, and an elastic member housed in the second recess. The elastic member covers the entire inner wall surface of the second recess. Fuel pump.

Images