JP2020020276A - Electromagnetic valve mechanism and fuel pump including the same - Google Patents

Abstract

To provide an electromagnetic valve which achieves improvement of production efficiency during pump assembly, inhibits erosion by cavitation during use of a fuel pump, and achieves high reliability and high quality.SOLUTION: An electromagnetic valve mechanism 300 of the invention includes: a fixed core 39; a movable core 36 which is suctioned by the fixed core 39; and a fixing member 71 which is disposed in a recessed part 39a of the fixed core 39 and formed separately from the fixed core 39. An inner diameter part 39c of the recessed part 39a of the fixed core 39 and an outer diameter part 71b of the fixed member 71 contact with each other in a position spaced apart from a bottom surface 39b of the recessed part 39a to form a space 72 (a liquid chamber) between an axial outer end surface 71c of the fixed member 71 and the bottom surface 39b of the recessed part 39a.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an electromagnetic valve mechanism and a fuel pump having the same for a vehicle component.

  As a prior art of the electromagnetic valve mechanism of the present invention, there is one disclosed in Patent Document 1. In paragraph 0030 of Patent Document 1, “the guide pin is formed to have a higher hardness than the fixed core, the movable core, and the second spring by, for example, quenching a martensitic stainless steel. Vickers hardness is Hv 400 or more, preferably Hv 650 or more. " In paragraph 0057, “a guide pin is provided with a hole communicating with the guide pin in the axial direction. With this, it is possible to bleed air deep in the first storage chamber when the guide pin is press-fitted. It can be securely pressed into the inner wall of the small-diameter hole. " Furthermore, the same paragraph states that "the gap between the outer wall of the base of the guide pin and the inner wall of the small-diameter hole can be made substantially 0. Therefore, erosion occurs on the inner wall of the small-diameter hole located radially outside the base. Can be reliably suppressed. "

JP 2012-136994 A

  Patent Literature 1 describes that a guide pin as a spring receiver is press-fitted and fixed in an inner cylindrical space of a fixed core, and the spring receiver is formed of a harder member than the fixed core, the movable core, and the second spring. In addition, in the center of the guide pin, a through hole is formed at the center of the guide pin for bleeding air in a sealed space formed between the guide pin and the fixed core at the time of press-fitting. Is touching. However, there is no mention of erosion generated in the fixed core at the inner end face of the through hole.

  In recent years, the present inventor has found that erosion due to cavitation may occur in the fixed core at the back end face of the through hole with the increase in fuel pressure, the flow rate, the diversification of fuel, and the complexity of the use environment. Found them. Therefore, an object of the present invention is to suppress the occurrence of erosion due to cavitation in the fixed core at the back end face of the through hole even under such a severe environment.

In order to achieve the above object, the present invention provides an electromagnetic valve mechanism including a fixed core and a movable core sucked by the fixed core, wherein the solenoid valve mechanism is disposed in a recess of the fixed core and is separate from the fixed core. A fixing member composed of a member, wherein an inner diameter portion of the concave portion of the fixed core and an outer diameter portion of the fixing member contact each other at a position separated from a bottom surface of the concave portion, so that a shaft of the fixing member is provided. A space is formed between a direction outer end surface and the bottom surface of the recess, and the fixing member communicates the space and a space formed on the opposite side of the space with the fixing member therebetween. Communicating hole was formed.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the electromagnetic valve mechanism which suppresses erosion generation | occurrence | production by cavitation in the fixed core of the back end surface of a through-hole, and the fuel pump provided with this.
Other configurations, operations, and effects of the present invention will be described in detail in the following embodiments.

1 shows a configuration diagram of an engine system to which a high-pressure fuel pump is applied. FIG. 2 is a longitudinal sectional view of the high-pressure fuel pump shown in FIG. 1. FIG. 2 is a horizontal cross-sectional view of the high-pressure fuel pump illustrated in FIG. 1 as viewed from above. FIG. 3 is a longitudinal sectional view of the high-pressure fuel pump shown in FIG. 1 as viewed from a different direction from FIG. 2. FIG. 2 is an enlarged vertical sectional view of an electromagnetic valve mechanism of the high-pressure fuel pump shown in FIG. 1, showing a state where the electromagnetic valve mechanism is in an open state. The state where the movable core 36 of the electromagnetic suction valve mechanism 300 moves in the direction of the fixed core 39 (valve closing direction) is shown. The state where the movable core 36 of the electromagnetic suction valve mechanism 300 is in contact with the fixed core 39 is shown. This shows a state in which the fluid in the recess 39a continues to flow out due to the inertial force of the fluid of the electromagnetic suction valve mechanism 300. 4 is a diagram illustrating a mechanism in which erosion occurs in the electromagnetic suction valve mechanism 300. The state before the fixed core 39 and the movable core 36 of the electromagnetic suction valve mechanism 300 are separated is shown. The state where the movable core 36 of the electromagnetic suction valve mechanism 300 moves in the valve opening direction and separates from the fixed core 39 is shown. 4 is a diagram illustrating a mechanism in which cavitation occurs in the electromagnetic suction valve mechanism 300. 4 is a diagram illustrating a mechanism in which erosion occurs in the electromagnetic suction valve mechanism 300. FIG. 1 is an enlarged vertical sectional view of an electromagnetic valve mechanism showing a configuration according to an embodiment of the present disclosure. FIG. 9 is an enlarged vertical sectional view around a high-hardness member (spring support portion) for explaining the effect of the solenoid valve shown in FIG. 8. FIG. 9 is an enlarged vertical sectional view around a high-hardness member (spring support portion) for explaining the effect of the solenoid valve shown in FIG. 8.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, a high-pressure fuel supply pump (hereinafter, referred to as a fuel pump) including the electromagnetic valve mechanism of the present embodiment will be described.
FIG. 1 shows an overall configuration diagram of the engine system. The portion surrounded by a broken line indicates the main body of the fuel pump, and the mechanism and parts shown in the broken line indicate that the components are integrated into the pump body 1. FIG. 1 is a diagram schematically showing the operation of the engine system, and the detailed configuration is different from the configuration of the fuel pump shown in FIG. 2 and thereafter. FIG. 2 is a longitudinal sectional view of the fuel pump of the present embodiment, and FIG. 3 is a horizontal sectional view of the fuel pump viewed from above. FIG. 4 is a longitudinal sectional view of the fuel pump viewed from a different direction from FIG. FIG. 5 is an enlarged view of the electromagnetic valve mechanism 300 (electromagnetic suction valve mechanism).

  Fuel in the fuel tank 20 is pumped up by a feed pump 21 based on a signal from an engine control unit 27 (hereinafter, referred to as an ECU). This fuel is pressurized to an appropriate feed pressure and sent to the low-pressure fuel inlet 10a of the fuel pump through the suction pipe 28.

  The fuel that has passed through the suction joint 51 (FIG. 3) from the low-pressure fuel suction port 10a is sucked into the electromagnetic valve mechanism 300 constituting the variable capacity mechanism via the damper chambers (10b, 10c) in which the pressure pulsation reduction mechanism 9 is disposed. It reaches port 31b.

  The fuel that has flowed into the solenoid valve mechanism 300 flows into the pressurizing chamber 11 through a suction port that is opened and closed by the suction valve 30. A reciprocating power is applied to the plunger 2 by a cam 93 (cam mechanism) of the engine. Due to the reciprocating motion of the plunger 2, fuel is sucked from the intake valve 30 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke. The pressurized fuel is fed through the discharge valve mechanism 8 to the common rail 23 on which the pressure sensor 26 is mounted.

  Then, the injector 24 injects fuel to the engine based on a signal from the ECU 27. The present embodiment is a fuel pump applied to a so-called direct injection engine system in which the injector 24 injects fuel directly into the cylinder of the engine. The fuel pump discharges a desired flow rate of the supplied fuel according to a signal from the ECU 27 to the electromagnetic valve mechanism 300.

  As shown in FIGS. 2 and 3, the fuel pump according to the present embodiment is fixed in close contact with a fuel pump mounting portion 90 of the internal combustion engine. Specifically, as shown in FIG. 3, a screw hole 1b is formed in a mounting flange 1a provided on the pump body 1, and a plurality of bolts (not shown) are inserted into this. As a result, the mounting flange 1a comes into close contact with the fuel pump mounting portion 90 of the internal combustion engine and is fixed. An O-ring 61 is fitted into the pump body 1 for sealing between the fuel pump mounting portion 90 and the pump body 1 to prevent the engine oil from leaking outside.

    As shown in FIGS. 2 and 4, a cylinder 6 that guides the reciprocating motion of the plunger 2 and forms a pressurizing chamber 11 together with the pump body 1 is attached to the pump body 1. That is, the plunger 2 changes the volume of the pressurizing chamber by reciprocating inside the cylinder. An electromagnetic valve mechanism 300 for supplying fuel to the pressurizing chamber 11 and a discharge valve mechanism 8 for discharging fuel from the pressurizing chamber 11 to a discharge passage are provided. The plunger 2 includes a large diameter portion 2a and a small diameter portion 2b, and the upper end surface of the large diameter portion 2a faces the pressurizing chamber 11.

  The cylinder 6 is pressed into the pump body 1 on the outer peripheral side. An insertion hole for inserting the cylinder 6 from below is formed in the pump body 1, and an inner peripheral protrusion deformed inward so as to contact the lower surface of the fixed portion 6 a of the cylinder 6 at the lower end of the insertion hole. Is done. The upper surface of the inner peripheral convex portion of the pump body 1 presses the fixing portion 6a of the cylinder 6 upward in the drawing, and seals the upper end surface of the cylinder 6 so that the fuel pressurized in the pressurizing chamber 11 does not leak to the low pressure side. ing.

  At the lower end of the plunger 2, there is provided a tappet 92 that converts the rotational motion of a cam 93 attached to a camshaft of the internal combustion engine into a vertical motion and transmits the vertical motion to the plunger 2. The plunger 2 is pressed against the tappet 92 by the spring 4 via the retainer 15. This allows the plunger 2 to reciprocate up and down with the rotational movement of the cam 93.

  In addition, a plunger seal 13 held at the lower end of the inner periphery of the seal holder 7 is installed so as to slidably contact the outer periphery of the plunger 2 at the lower part of the cylinder 6 in the drawing. Thereby, when the plunger 2 slides, the fuel in the sub chamber 7a is sealed to prevent the fuel from flowing into the internal combustion engine. At the same time, it prevents lubricating oil (including engine oil) for lubricating the sliding portion in the internal combustion engine from flowing into the inside of the pump body 1.

  As shown in FIGS. 3 and 4, a suction joint 51 is attached to a side surface of the pump body 1 of the fuel pump. The suction joint 51 is connected to a low-pressure pipe that supplies fuel from the fuel tank 20 of the vehicle, and the fuel is supplied from here to the inside of the fuel pump. The suction filter 52 has a role of preventing foreign substances existing between the fuel tank 20 and the low-pressure fuel suction port 10a from being absorbed into the fuel pump by the flow of the fuel.

  The fuel that has passed through the low-pressure fuel intake port 10a travels to the pressure pulsation reduction mechanism 9 through a low-pressure fuel intake passage that is vertically communicated with the pump body 1 shown in FIG. The pressure pulsation reduction mechanism 9 is disposed in a damper chamber (10b, 10c) between the damper cover 14 and the upper end surface of the pump body 1, and is supported from below by a holding member 9a disposed on the upper end surface of the pump body 1. You. Specifically, the pressure pulsation reduction mechanism 9 is a metal damper configured by stacking two metal diaphragms. A gas of 0.3 MPa to 0.6 MPa is sealed in the pressure pulsation reducing mechanism 9, and the outer peripheral edge is fixed by welding. For this purpose, the outer peripheral portion is configured to be thin and thicker toward the inner peripheral side.

  Then, as shown in FIG. 2, a projection for fixing the outer peripheral edge of the pressure pulsation reducing mechanism 9 from below is formed on the upper surface of the holding member 9a. On the other hand, on the lower surface of the damper cover 14, a convex portion for fixing the outer peripheral edge of the pressure pulsation reducing mechanism 9 from above is formed. These convex portions are formed in a circular shape, and the pressure pulsation reducing mechanism 9 is fixed by being sandwiched by these convex portions. The damper cover 14 is pressed into the outer edge of the pump body 1 and fixed. At this time, the holding member 9a is elastically deformed to support the pressure pulsation reducing mechanism 9.

  In this manner, on the upper and lower surfaces of the pressure pulsation reducing mechanism 9, the low-pressure fuel suction port 10a and the damper chambers (10b, 10c) communicating with the low-pressure fuel suction passage are formed. Although not shown in the figure, the holding member 9a is provided with a passage communicating between the upper side and the lower side of the pressure pulsation reducing mechanism 9, whereby the damper chambers (10b, 10c) are connected to the pressure pulsation reducing mechanism. 9 are formed on the upper and lower surfaces.

  The fuel that has passed through the damper chambers (10b, 10c) then reaches a suction port 31b of the electromagnetic valve mechanism 300 via a suction passage 10d (a low-pressure fuel suction passage) formed vertically communicating with the pump body. The suction port 31b is formed to communicate vertically with the suction valve seat member 31 forming the suction valve seat 31a. The lower end surface of the large diameter portion 2a of the plunger 2 faces the sub-chamber 7a (seal chamber), and the lower end surface of the large diameter portion 2a reciprocates up and down, thereby increasing the volume of the sub-chamber 7a. The volume of the chamber 11 increases and decreases in the opposite manner. Here, the damper chambers (10b, 10c) and the sub chamber 7a (seal chamber) are connected to the pump body 1 by a communication passage 1d formed in the axial direction of the plunger.

  The electromagnetic valve mechanism 300 (electromagnetic suction valve mechanism) will be described in detail with reference to FIG. The bobbin 45 is wound with a coil 43 (electromagnetic coil) in which a copper wire is wound a plurality of times. The terminal 46 shown in FIG. 2 has two connection terminals, and both ends of the copper wire of the coil 43 are electrically connected to the respective connection terminals, and are connected so as to be able to conduct electricity. The terminal 46 is molded integrally with the connector 47 (shown in FIG. 2), and the other end can be connected to the engine control unit side.

  The first yoke 42 is a cup-shaped metal member, and is disposed inside the coil 43 in the axial direction (the right side in FIG. 5) and radially outside the coil (the upper side or the lower side in FIG. 5). The second yoke 44 is a metal member disposed axially outside (left side in FIG. 5) of the coil 43 and functioning as a cover member that covers the large diameter portion of the magnetic core 39 and the bobbin 45 from the outside in the axial direction. The first yoke 42 and the second yoke 44 are integrally molded and fixed with the connector 47 which is a resin member. The outer core 38 is press-fitted and fixed in a hole at the center of the first yoke 42. The opposite side of the outer core 38 from the press-fit portion is fixed to the pump body 1 by welding or the like.

  The inner peripheral portion of the second yoke 44 is configured so as to be in contact with the outer peripheral portion of the small diameter portion of the fixed core 39 or to form a slight clearance. Further, the outer peripheral portion of the second yoke 44 is configured so as to be in contact with the inner peripheral portion of the cylindrical side surface portion of the first yoke 42 or to form a slight clearance. A fixing pin 832 is attached to the outer peripheral portion of the small diameter portion of the fixed core 39, and generates an urging force to press the axially outer yoke portion 44a of the second yoke 44 against the large diameter portion of the fixed core 39 from the outside in the axial direction. I do. The fixing pin 832 may be fixed by cutting a corner portion on the inner peripheral side into the fixing core 39, or may be fixed by welding or the like.

  Both the first yoke 42 and the second yoke 44 are made of a magnetic stainless material in order to form a magnetic circuit and in consideration of corrosion resistance. The bobbin 45 and the connector 47 are made of a high-strength heat-resistant resin in consideration of strength characteristics and heat-resistant characteristics.

  Inside the bobbin 45 and the coil 43 in the radial direction, one end of the seal ring 48 is fixed to the outer core 38 by welding, and the other end is fixed to the fixed core 39 by welding. On the radial inside of the seal ring 48 or the outer core 38, the anchor 36 (movable element) and the rod 35, which are movable parts, are arranged. The rod 35 is urged by a rod urging spring 40 toward the valve opening direction, and the anchor 36 is urged by an anchor urging spring 41 toward the valve closing direction. The rod 35 is slidably held in the axial direction on the inner peripheral side of the rod guide 37 and the inner peripheral side of the anchor 36.

  When a current flows through the coil 43, a magnetic attraction force is generated, and the anchor 36 is drawn toward the fixed core 39. Since the anchor 36 has one or more through holes 36a penetrating in the axial direction, the anchor 36 can freely and smoothly move in the axial direction in the fuel, thereby eliminating the restriction of the movement due to the pressure difference before and after the anchor. .

  An axially inner portion of the rod guide 37 is inserted into an inner peripheral portion of an insertion hole formed in the pump body 1, and a seat portion 31a is formed by an axial end of the rod guide 37. The rod guide 37 is arranged to be sandwiched between the outer core 38 and the pump body 1. The rod guide 37 is also provided with a through hole 37a that penetrates in the axial direction, so that when the anchor moves in the axial direction, the movement of the internal fuel is not hindered.

  A radially inner side of the fixed core 39 is formed with a recessed portion that is recessed outward in the axial direction. A rod biasing spring 40 is disposed in the recessed portion, and biases the flange 35a of the rod 35 in the valve opening direction. An end surface of the flange 35 a of the rod 35 opposite to the rod urging spring 40 is engaged with the anchor 36. The distal end of the rod 35 urges the suction valve 30 in a direction to separate the suction valve 30 from the suction valve seat 31a (valve opening direction).

  One end of the anchor urging spring 41 is inserted into a cylindrical central bearing 37b provided on the center side of the rod guide 37, and the other end urges the anchor 36 in the valve closing direction. The moving amount 36e of the anchor 36 is set to be larger than the moving amount 30e of the suction valve 30, and prevents the suction valve 30 from interfering when the valve is closed.

  The outer core 38, the first yoke 42, the second yoke 44, the fixed core 39, and the anchor 36 form a magnetic circuit around the coil 43. Generates magnetic attraction. Since the anchor 36 and the fixed core 39 form a magnetic attraction surface, it is desirable to use a material having good magnetic properties in performance.

  The seal ring 48 is desirably a non-magnetic material in order to allow a magnetic flux to flow between the anchor 36 and the fixed core 39. In addition, in order to absorb the impact at the time of collision, it is desirable to use a thin stainless steel material having a large elongation. Specifically, austenitic stainless steel is used.

  As shown in FIG. 3, the discharge valve mechanism 8 provided at the outlet of the pressurizing chamber 11 includes a discharge valve seat 8a, a discharge valve 8b which is seated on or separated from the discharge valve seat 8a, and a discharge valve 8b which is connected to the discharge valve seat 8a. And a discharge valve stopper 8d for determining the lift of the discharge valve 8b. The discharge valve stopper 8d and the pump body 1 are joined by welding at a contact portion 8e to shut off fuel from the outside.

  When there is no fuel pressure difference between the pressurizing chamber 11 and the discharge valve chamber 12a, the discharge valve 8b is pressed against the discharge valve seat 8a by the urging force of the discharge valve spring 8c and is in a closed state. Only when the fuel pressure in the pressurizing chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 12a does the discharge valve 8b open against the discharge valve spring 8c. The high-pressure fuel in the pressurizing chamber 11 is discharged to the common rail 23 through the discharge valve chamber 12a, the fuel discharge passage 12b, and the fuel discharge port 12.

  When the discharge valve 8b is opened, it comes into contact with the discharge valve stopper 8d, and the lift amount is limited. As a result, it is possible to prevent the fuel discharged at a high pressure into the discharge valve chamber 12a from flowing back into the pressurization chamber 11 again due to the lift amount being too large and the delay in closing the discharge valve 8b, thereby lowering the efficiency of the fuel pump. Can be suppressed. The discharge valve 8b is guided by the outer peripheral surface of the discharge valve stopper 8d.

  The relief valve mechanism 200 shown in FIG. 3 includes a relief body 201, a relief valve 202, a relief valve holder 203, a relief spring 204, and a spring stopper 205. The relief body 201 is provided with a seat portion. The relief valve 202 receives the load of the relief spring 204 via the relief valve holder 203, is pressed by the seat portion of the relief body 201, and shuts off the fuel in cooperation with the seat portion. The valve opening pressure of the relief valve 202 is determined by the load of the relief spring 204. The spring stopper 205 is press-fitted and fixed to the relief body 201, and adjusts the load of the relief spring 204 depending on the position where the press-fitting is fixed.

  When the pressure of the fuel discharge port 12 becomes abnormally high due to a failure of the electromagnetic valve mechanism 300 or the like, and becomes higher than the set pressure of the relief valve mechanism 200, the abnormally high pressure fuel is relieved to the pressurizing chamber 11 via the relief passage. The pressurizing chamber 11 is constituted by the pump body 1, the solenoid valve mechanism 300, the plunger 2, the cylinder 6, and the discharge valve mechanism 8 described above.

  The detailed operation of the solenoid valve mechanism 300 will be described with reference to FIG. When the plunger 2 moves downward in the direction of the cam 93 due to the rotation of the cam 93, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. When the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the suction port 31b in this state, the suction valve 30 is opened. Reference numeral 30e denotes the maximum lift (opening amount) of the suction valve 30. At this time, the suction valve 30 contacts the stopper 32. When the suction valve 30 is opened, an opening 31c formed in the suction valve seat member 31 is opened. The fuel flows into the pressurizing chamber 11 through the opening 31c and the hole 1c formed in the pump body 1 in the lateral direction. The hole 1c also forms a part of the pressure chamber 11.

  When the plunger 2 reaches the bottom dead center and completes the suction stroke, the plunger 2 starts to move upward and moves to the rising stroke. Here, the coil 43 remains in the non-energized state, and no magnetic biasing force acts. The rod urging spring 40 urges the flange 35a (rod convex) which is convex on the outer diameter side of the rod 35, and has a necessary and sufficient urging force to keep the suction valve 30 open in a non-energized state. It is set as follows. Although the volume of the pressurizing chamber 11 decreases with the upward movement of the plunger 2, in this state, the fuel once sucked into the pressurizing chamber 11 is sucked again through the opening 31c of the suction valve 30 in the valve-open state. Since the pressure is returned to the passage 10d, the pressure in the pressurizing chamber does not increase. This process is called a return process.

  In this return stroke, part of the fuel returned to the suction passage 10d due to the upward movement of the plunger 2 flows from the damper chambers (10b, 10c) through the communication passage 1d, and flows into the sub-chamber 7a. On the other hand, in the lowering stroke of the plunger 2, since the lower end surface of the large diameter portion 2a faces the sub-chamber 7a, the volume of the sub-chamber 7a becomes small. It is flushed to the damper chambers (10b, 10c) via 1d. As described above, the fuel moves between the damper chambers (10b, 10c) and the sub chamber 7a by the vertical movement of the large diameter portion 2a of the plunger 2, whereby the effect of reducing the pressure pulsation can be obtained.

  When a control signal from the ECU 27 is applied to the solenoid valve mechanism 300 in the return stroke, a current flows through the coil 43 via the terminal 46. Then, a magnetic attraction force acts between the fixed core 39 and the anchor 36, and the fixed core 39 and the anchor 36 collide on the magnetic attraction surface S. The magnetic attraction force overcomes the urging force of the rod urging spring 40 to urge the anchor 36, and the anchor 36 engages with the collar 35 a to move the rod 35 away from the suction valve 30.

  At this time, the suction valve 30 is closed by the urging force of the suction valve urging spring 33 and the fluid force caused by the fuel flowing into the suction passage 10d. After the valve is closed, the fuel pressure in the pressurizing chamber 11 rises with the upward movement of the plunger 2, and when the pressure becomes equal to or higher than the pressure in the fuel discharge port 12, high-pressure fuel is discharged through the discharge valve mechanism 8, and is discharged to the common rail 23. Supplied. This process is called a discharge process.

  That is, the rising stroke between the lower starting point and the upper starting point of the plunger 2 includes a returning stroke and a discharging stroke. By controlling the timing of energizing the coil 43 of the electromagnetic valve mechanism 300, it is possible to control the amount of high-pressure fuel to be discharged.

  The outer core 38 has an inner peripheral surface on which the outer peripheral surface of the anchor 36 slides. The seal ring 48 is desirably formed of a material having low hardness (for example, austenitic stainless steel). When the fixed core 39 and the anchor 36 collide with each other on the magnetic attraction surface S, the impact load can be reduced by elastically deforming the seal ring 48.

  The fixed core 39 and the outer core 38 have insertion portions 39ins and 38ins that are inserted into the cylindrical seal ring 48, respectively. The fixed core 39 and the outer core 38 have an outer peripheral surface that is flush with the outer peripheral surface CS of the seal ring 48 when inserted into the seal ring 48. This facilitates attachment of other components such as the bobbin 45, for example.

  Next, referring to FIGS. 6 and 7, a mechanism will be described in which the fixed core recess has a severe environment against cavitation erosion.

  FIGS. 6A to 6D show an environmental change in the vicinity of the concave portion of the fixed core 36 when the fixed core 39 and the movable core 36 come into contact with each other. First, FIG. 6A shows a state in which a magnetic attraction force is generated on the magnetic attraction surface S when the coil 43 is energized, and the movable core 36 moves in the direction of the fixed core 39 (valve closing direction). The fluid removed with the movement of the movable core 36 flows into the communication passage 36a of the movable core 36, and also flows into the recess 39a of the fixed core 39. As a result, the region V of the bottom surface 39b (the back end surface) of the concave portion 39a of the fixed core 39 becomes higher in pressure because there is no escape place for the fluid.

  Next, FIG. 6B shows a state where the sucked movable core 36 collides with the fixed core 39 so that they come into contact with each other. When the movable core 36 stops, the flow of the fluid flowing into the concave portion 39a of the fixed core 39 also stops, so that the high-pressure fluid in the concave portion 39a of the fixed core 39 is removed from the concave portion 39a by the movable core 36. And the pressure in the region V gradually decreases. Then, as shown in FIG. 6C, the fluid in the concave portion 39a continues to flow out due to the inertial force of the fluid, so that the pressure in the region V continues to drop, and the cavitation is generated by dropping below the saturated vapor pressure of the fluid. I do.

  As a result, as shown in FIG. 6D, the fluid flowing out of the concave portion 39a collides with another part and is reflected by the pressure wave, or the fluid flowing into the concave portion due to the low pressure of the concave portion 39a. , The pressure in the region V where the cavitation has occurred is recovered. As a result, the present inventors have found that cavitation collapses, and the impact force may cause erosion of the concave portion 39a of the fixed core 39, particularly the bottom surface 39b (back end surface). is there.

  On the other hand, FIGS. 7A to 7D show an environmental change near the recess 39 a of the fixed core 39 when the fixed core 39 and the movable core 36 are separated. First, as shown in FIG. 7A, before separation, there is no change in volume in the vicinity of the concave portion 39a, so that there is basically no pressure fluctuation in the region V, and the device is in a static pressure state. . Next, as shown in FIG. 7B, the movable core 36 moves in the valve opening direction (to the right in FIG. 7B) to be separated from the fixed core 39. Then, the fluid flows into the volume generated between the fixed core 39 and the movable core 36 from the communication passage 36a or the concave portion 39a, and as a result, the pressure in the region V on the bottom surface 39b (the back end surface) of the concave portion 39a is increased. It is going down.

  Further, as shown in FIG. 7 (c), when the pressure continues to decrease, the pressure in the region V falls below the saturated vapor pressure, so that cavitation occurs. Then, as shown in FIG. 7D, a pressure wave generated when the mover 36 stops moving, or a reflow of fluid into the concave portion 39a due to the low pressure of the concave portion 39a. The pressure in the region V where cavitation has occurred is restored. As a result, the cavitation collapses, and the impact force may cause erosion of the concave portion 39a of the fixed core 39, particularly the bottom surface 39b (back end surface).

  According to the above mechanism, as the moving speed of the movable core 36 increases, the environment V of the concave portion 39a of the fixed core 39, in particular, the region V of the bottom surface 39b (back end surface) becomes more severe against cavitation erosion.

  As the discharge pressure and the flow rate of the fuel pump are increased in accordance with recent strict environmental regulations of automobiles, a large lift amount of the cam 93 is required. Further, as described above, since the moving speed of the movable core 36 has a qualitative correlation with the lift amount of the cam 93, the fuel pump has a severe environment in which cavitation erosion is likely to occur. Therefore, it can be said that suppressing the occurrence of cavitation erosion in the region V of the bottom surface 39b (back end surface) of the concave portion 39a of the fixed core 39 of the fuel pump is indispensable to comply with the environmental regulations of the automobile.

  In addition, fuel having a low saturated vapor pressure tends to generate cavitation, and ethanol fuel has a strong erosion power when collapsed. Therefore, it can be said that the recent diversification of the fuel is a severe environment in which cavitation erosion is likely to occur in the fuel pump.

  If cavitation erosion occurs and parts are damaged, there is a possibility that the cut parts will become foreign substances and cause poor performance of the fuel pump. In view of the recent environmental changes described above, the present embodiment provides an electromagnetic valve mechanism that can reduce the risk of cavitation erosion occurring in the electromagnetic valve mechanism, particularly at the bottom surface 39b of the recess 39a of the fixed core 39.

  For this reason, as shown in FIG. 8, the electromagnetic valve mechanism 300 of this embodiment is arranged in the fixed core 39, the movable core 36 attracted by the fixed core 39, and the recess 39 a of the fixed core 39, And a fixing member 71 formed of a separate member. Further, the inner diameter portion 39c of the concave portion 39a of the fixed core 39 and the outer diameter portion 71b of the fixing member 71 come into contact with each other at a position away from the bottom surface 39b of the concave portion 39a, so that the axially outer end surface 71c of the fixing member 71 is recessed. A space 72 (liquid chamber) is formed between the portion 39a and the bottom surface 39b. Further, in this embodiment, the fixing member 71 has a communication hole 74 (through hole) that communicates the space 72 with the space (75, 39a) formed on the opposite side of the space 72 with the fixing member 71 therebetween. Is formed.

  The solenoid valve mechanism 300 is provided in a recess 39 a formed on the inner diameter side of the fixed core 39 and includes a spring (rod urging spring 40) for urging the movable core 36 or the rod 35. The fixing member 71 described above is desirably a spring supporting portion 71 that is disposed in the recess 39a of the fixing core 39 and supports a spring (rod urging spring 40). Further, the inner diameter portion 39c of the concave portion 39a and the outer diameter portion 71b of the spring support portion 71 contact each other at a position away from the bottom surface 39b of the concave portion 39a, so that the axial outer end surface 71c of the spring support portion 71 and the concave portion 39a. A space 72 is formed between the bottom surface 39b and the bottom surface 39b. A communication hole 74 is formed in the spring support 71 to communicate the space 72 with the spring spaces (75, 39a) in which the springs (rod biasing springs 40) are arranged.

  In the present embodiment, the spring supporting portion 71 configured in a cup shape is fastened to the fixed core 39 by the press-fit portion 77. That is, the spring support portion 71 has a large diameter portion 71d and a small diameter portion 71e, and the outer diameter portion 71b of the large diameter portion 71d is press-fitted into the inner diameter portion 39c of the concave portion 39a of the fixed core 39, whereby the spring is The support part 71 is fixed. The large-diameter portion 71d and the small-diameter portion 71e are formed in the order of the large-diameter portion 71d and the small-diameter portion 71e toward the outside in the axial direction. In addition, as shown in FIG. 8, it is desirable that the axial length of the large diameter portion 71d is equal to or longer than the axial length of the small diameter portion 71e. Thereby, it is possible to maintain the press-fitting length necessary for fixing the spring support 71.

  By providing the communication hole 74 described above, when the spring support portion 71 is press-fitted and fastened to the fixed core 39, the space 72 therebetween can be prevented from becoming a closed space. Therefore, the press-fitting can be performed smoothly, the production efficiency can be increased, and the production cost can be reduced.

  In the present embodiment, a communication space 75 is formed in the spring support portion 71 on the inner diameter side in the axial direction outside of the spring support surface 76 and communicates the communication hole 74 and the spring space 39a. In this case, it is desirable that the area of the space 72 be larger than the area of the communication space 75. Further, between a portion located on the innermost side in the axial direction of the bottom surface 39b of the concave portion (39a, 72) of the space 72 and a portion located on the outermost side in the axial direction of the axially outer end surface 71c of the spring support portion 71. The space 72 is desirably formed such that the length 72a of the space 72 is larger than the diameter 74a of the communication hole 74. Further, it is desirable that the above-mentioned length 72a is longer than the axial length 74b of the communication hole 74. It is desirable that the communication hole 74 be formed such that the axial length 74 b is larger than the diameter 74 a of the communication hole 74.

  Details of the effect of the communication space 75 will be described later with reference to FIG. The spring supporting portion 71 is desirably made of a material having a higher hardness than the fixed core 39. For example, it is preferable to use a high-hardness martensitic stainless steel or the like. It is desirable that the fixed core 39 is made of ferritic stainless steel having high magnetism. The collision surface S of the fixed core 39 colliding with the movable core 36 is subjected to a hard surface treatment to suppress wear due to the collision. For example, a plating process is performed on the collision surface S of the fixed core 39. On the other hand, since a material having high hardness is employed for the spring support 71 as described above, the spring support 71 is configured not to be subjected to surface treatment.

  Here, the fixed core 39 is composed of 0.010% by mass of carbon (C), 0.77% by mass of silicon (Si), 0.29% by mass of manganese (Mn), 0.031% by mass of phosphorus (P), 0.02% by mass of sulfur (S), 0.10% by mass of chromium (Cr), 0.01% by mass of copper (Cu), 0.19% by mass of nickel It is preferable to use a material containing (Ni), 0.27% by mass of aluminum (Al), 13.99% by mass of chromium, and 0.008% by mass of nitrogen (N) as components. Thereby, the above-described plating process can be easily performed, and the spring support portion 71 can be fixed by press-fitting, so that production efficiency can be improved.

  As described above, the fuel pump according to the present embodiment includes the plunger 2 that increases and decreases the volume of the pressurizing chamber 11 and the discharge valve mechanism 8 that is disposed on the discharge side of the pressurizing chamber 11. The electromagnetic valve mechanism described above is employed for the suction valve mechanism 300 arranged on the suction side.

Next, effects of such a configuration will be described with reference to FIGS.
FIG. 9 shows the flow of fuel near the spring support 71 when the anchor 36 as the movable core collides with the fixed core 39 (during suction). The fuel flows from the communication space 75 to the liquid chamber 72 through the communication hole 74. At this time, a pressure loss is generated in the communication hole 74 by making the diameter of the communication hole 74 smaller than the diameter of the communication space 75. As a result, as shown in FIG. 9, the high-speed fluid separates near the outlet of the communication hole 74, so that cavitation occurs.

  Here, if the spring support portion 71 is configured to abut against the bottom surface 39b (back end surface) of the fixed core 39, the generated cavitation has a lower hardness than the spring support portion 71 and is made of a magnetic material. It occurs near the bottom surface 39b (back end surface) of the core 39. The inventors of the present invention have eagerly studied that this causes erosion of the bottom surface 39b (the rear end surface).

  Therefore, in the present embodiment, as described above, the liquid chamber 72 is provided between the spring support portion 71 and the bottom surface 39b (back end surface) of the fixed core 39. This causes the generated cavitation to collapse in the liquid. Therefore, it is possible to protect the fixed core 39 from erosion due to cavitation. Of course, cavitation collapse occurs near the spring support 71, but since the spring support 71 is made of a high-hardness material such as martensite, erosion does not occur.

  Here, in order to cause cavitation to collapse in the liquid in the present configuration, the relationship between the communication hole 74 and the liquid chamber 72 is important. In order for the cavitation generated by the separation of the fuel, which has flowed at a high speed in the communication hole 74, to sufficiently collapse in the liquid in the liquid chamber 72, the length of the communication hole 74, which is the approaching section, in the axial direction is smaller than the axial length of the communication hole 74. It is desirable that the axial length of a certain liquid chamber 72 and the rear end face 73 be longer. By ensuring the volume and the axial length of the liquid chamber 72 as described above, it is possible to cause the generated cavitation to collapse in the liquid before reaching the bottom surface 39b (the back end surface).

  Similarly, it is also effective to make the communication hole 74 small in diameter. The kinetic energy of the fluid passing through the communication hole 74 can be reduced by reducing the diameter of the communication hole 74 and generating a large pressure loss. This makes it possible to reduce the reach of the cavitation after passing through the communication hole 74. Therefore, it is desirable that the axial length 74b of the communication hole 74 is longer than the diameter 74a. With the above structure, press-fitting can be performed smoothly during assembly. Therefore, it is possible to provide a high-reliability and high-quality fuel pump capable of suppressing the occurrence of cavitation erosion when the pump is used, while improving the production efficiency.

  On the other hand, FIG. 10 shows the flow of fuel near the spring support 71 when the anchor 36 as the movable core separates from the fixed core 39. In this case, the direction of the fuel flowing through the communication hole 74 of the spring support 71 is opposite to the direction at the time of suction in FIG. Therefore, cavitation erosion of components inside the space 39a in which the rod urging spring 40 is arranged is concerned. Therefore, in this embodiment, as shown in FIG. 8, a through space 74 is provided on the inner side of the spring support surface 76 of the spring support 71. Cavitation generated from the outlet of the communication hole 74 can be collapsed in the through space 74, and the rod urging spring 40 and the gap 78 between the rod urging spring 40 of the fixed core 39 and the rigid erosion environment It is possible to protect from.

  That is, it is shown that the configuration of the present embodiment is effective not only at the time of suction of the solenoid valve, but also at the time of separation of the solenoid valve, and a general erosion covering the entire environment region where the solenoid valve is used. It means that it is a measure.

  As described above, according to this embodiment, it is possible to smoothly press-fit the fuel pump when assembling the fuel pump, improve the production efficiency, and when using the pump, use a highly reliable, high-quality solenoid valve and a fuel pump equipped with the solenoid valve. It can be provided.

  As described above, the present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations. Further, for a part of the configuration of each embodiment, it is possible to add, delete, or replace another configuration of the embodiment.

  In the present embodiment, the magnetic core may be formed of not only ferrite-based magnetic stainless steel having relatively small hardness but also precipitation-hardened electromagnetic stainless steel having high hardness or SUS630 (17Cr-4Ni-4CU-Nb). Good.

  In FIG. 8, the axial length of the communication space 75 is smaller than the axial length of the large-diameter portion 71e. It may be formed to be larger than the height. In addition, unlike FIG. 8, it is desirable that the communication space 75 be formed in a range from the large diameter portion 71e to the small diameter portion 71e in the axial direction. As a result, the volume of the communication space 75 can be ensured, so that the occurrence of cavitation erosion on the spring support surface 76 can be suppressed. That is, by generating cavitation erosion in the communication space 75, the reliability of the electromagnetic suction valve mechanism can be improved.

DESCRIPTION OF SYMBOLS 1 ... Pump body 1a ... Flange 1b ... Hole 1c ... Hole 2 ... Plunger 4 ... Spring 6 ... Cylinder 6a ... Fixed part 7 ... Seal holder 7a ... Subchamber 8 ... Discharge valve mechanism 8a ... Discharge valve seat 8b ... Discharge valve 8c ... Discharge valve spring 8d Discharge valve stopper 8e Contact portion 9 Pressure pulsation reduction mechanism 9a Holding member 10a Low-pressure fuel suction port 10b, 10c Damper chamber 10d Suction passage 11 Pressurizing chamber 12 Fuel discharge port 12a ... discharge valve chamber 12b ... fuel discharge passage 13 ... plunger seal 14 ... damper cover 15 ... retainer 20 ... fuel tank 21 ... feed pump 23 ... common rail 24 ... injector 26 ... pressure sensor 27 ... engine control unit 28 ... suction pipe 30 ... suction Valve 30e Moving amount 31 Suction valve seat member 31a Suction valve seat 31b Suction port 31c Opening 32 Topper 33: Suction valve urging spring 35 ... Rod 35a ... Collar 36 ... Anchor 36a ... Through hole 36e ... Movement amount 37 ... Rod guide 37a ... Through hole 37b ... Central bearing 38 ... Outer core 39 ... Fixed core 40 ... Rod Energizing spring 41 Anchor urging spring 42 First yoke 43 Coil 44 Second yoke 45 Bobbin 46 Terminal 47 Connector 48 Seal ring 51 Suction joint 52 Suction filter 61 O-ring 71 Spring Support part 72 ... Liquid chamber 73 ... Fixed core inner end face 74 ... Communication hole 75 ... Penetration space 76 ... Spring support surface 77 ... Spring support part press-fit part 78 ... Inner diameter part 90 of the fixed core that forms a gap with the spring 90 ... Fuel pump mounting Part 92: Tappet 93 ... Cam 200 ... Relief valve mechanism 201 ... Relief body 202 ... Relief valve 203 ... Relief valve holder 04 ... relief spring 205 ... stopper 300 ... solenoid valve mechanism 832 ... fixed pin

Claims (16)

In a solenoid valve mechanism including a fixed core and a movable core sucked by the fixed core,
A fixed member disposed in the recessed portion of the fixed core and configured as a separate member from the fixed core,
The inner diameter portion of the recessed portion of the fixed core and the outer diameter portion of the fixing member contact at a position separated from the bottom surface of the recessed portion, so that the axially outer end surface of the fixed member and the bottom surface of the recessed portion are contacted. A space is formed between
An electromagnetic valve mechanism, wherein a communication hole is formed in the fixing member to communicate the space and a space formed on the opposite side of the space with the fixing member therebetween. A solenoid valve mechanism comprising: a fixed core, a movable core sucked by the fixed core, and a spring disposed in a recess formed on the inner diameter side of the fixed core and biasing the movable core or the rod. ,
A spring support portion that is arranged in the recessed portion of the fixed core and supports the spring;
By contacting the inner diameter of the recess and the outer diameter of the spring support at a position distant from the bottom of the recess, the axial outer end face of the spring support and the bottom of the recess are in contact with each other. A space is formed between them,
An electromagnetic valve mechanism, wherein a communication hole communicating the space and a spring space in which the spring is arranged is formed in the spring support portion. The electromagnetic valve mechanism according to claim 2,
The length between the portion located at the innermost position in the axial direction of the bottom surface of the concave portion of the space and the portion located at the outermost position in the axial direction of the axially outer end surface of the spring support portion, An electromagnetic valve mechanism in which the space is formed to be larger than a diameter of the communication hole. The electromagnetic valve mechanism according to claim 2,
The spring support portion is recessed axially outward on the inner diameter side, and a communication space that communicates the communication hole and the spring space is formed,
An electromagnetic valve mechanism configured such that an area of the space is larger than an area of the communication space in an axial cross section. The electromagnetic valve mechanism according to claim 2,
The spring support has a large diameter portion and a small diameter portion,
An electromagnetic valve mechanism in which the spring support portion is fixed by press-fitting the outer diameter portion of the large diameter portion into the inner diameter portion of the concave portion of the fixed core. The electromagnetic valve mechanism according to claim 5,
An electromagnetic valve mechanism in which the large-diameter portion and the small-diameter portion are formed in the order of the large-diameter portion and the small-diameter portion outward in the axial direction. The electromagnetic valve mechanism according to claim 4,
The spring support has a large diameter portion and a small diameter portion,
An electromagnetic valve mechanism formed such that an axial length of the communication space is larger than an axial length of the large diameter portion. The electromagnetic valve mechanism according to claim 6,
The spring support has a large diameter portion and a small diameter portion,
An electromagnetic valve mechanism wherein the communication space is formed in a range from the large diameter portion to the small diameter portion in the axial direction. The electromagnetic valve mechanism according to claim 2,
An electromagnetic valve mechanism formed such that an axial length of the communication hole is larger than a diameter of the communication hole. The electromagnetic valve mechanism according to claim 2,
An electromagnetic valve mechanism in which the spring support is made of a material having a higher hardness than the fixed core. The electromagnetic valve mechanism according to claim 2,
An electromagnetic valve mechanism, wherein the fixed core is made of ferritic stainless steel having high magnetism. The electromagnetic valve mechanism according to claim 2,
An electromagnetic valve mechanism in which the spring support is made of high-hardness martensitic stainless steel. The electromagnetic valve mechanism according to claim 2,
An electromagnetic valve mechanism in which a hard surface treatment is applied to a collision surface of the fixed core that collides with the movable core. The electromagnetic valve mechanism according to claim 13,
An electromagnetic valve mechanism configured such that the surface treatment is not performed on the spring support portion. The electromagnetic valve mechanism according to claim 4,
The spring support has a large diameter portion and a small diameter portion,
An electromagnetic valve mechanism configured such that the axial length of the large diameter portion is equal to or greater than the axial length of the small diameter portion. A plunger for increasing or decreasing the volume of the pressurizing chamber;
A discharge valve mechanism disposed on the discharge side of the pressurizing chamber,
2. A fuel pump in which the solenoid valve mechanism according to claim 1 is employed in a suction valve mechanism disposed on a suction side of the pressurizing chamber.

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