JP2016121585A - High pressure fuel pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure fuel pump capable of reducing operation sound.SOLUTION: A solenoid valve 10 for a high pressure fuel pump is operated in such a way that a movable core 20 supported by a housing 18 via a buffer mechanism 23 moves along an axis line L1. The buffer mechanism 23 includes an arm 42 extending in a moving direction of the movable core 20 and oscillatably supported in the moving direction in respect to the housing 18. One end part of the arm 42 is formed with a first contact part 43 and the other end part is formed with a second contact part 44. The movable core 20 is formed with a first contact surface 45 and a second contact surface 46. At least one of the first contact surface 45 and the second contact surface 46 is made as a slant surface where a total amount of one distance from an axis line L1 to a contact point between the first contact part 43 and the first contact surface 45 and another distance from the axis line L1 to a contact point between the second contact part 44 and the second contact surface 46 becomes large when the movable core 20 approaches a stator 17, and the farther apart a part from the stator 17, the longer a distance to the axis line L1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a high-pressure fuel pump.

  A direct injection internal combustion engine is provided with a high-pressure fuel pump for pumping high-pressure fuel to a fuel injection valve. Such a high-pressure fuel pump is provided with an electromagnetic valve for controlling the amount of fuel to be pumped to the fuel injection valve, as disclosed in Patent Document 1.

  The electromagnetic valve has a movable core and a stator, and moves the movable core in the approaching direction to the stator by electromagnetic force generated through energization of the coils of the stator. The solenoid valve has a spring that urges the movable core in a direction away from the stator, and moves the movable core in a direction away from the stator by the urging force of the spring when energization of the coil of the stator is stopped.

  In the high-pressure fuel pump, the valve body of the solenoid valve is opened and closed by moving the movable core closer to or away from the stator through such energization control of the coil, and the amount of fuel pumped to the fuel injection valve by the solenoid valve is controlled. I try to adjust it.

JP 2014-134208 A

  By the way, in the high-pressure fuel pump, since the hitting sound is generated when the movable core of the electromagnetic valve moves in the approaching direction to the stator and comes into contact with the stator, the operation noise when pumping the fuel increases. There is.

  In Patent Document 1, considering that the magnitude of the kinetic energy of the movable core (first member) when contacting the stator affects the magnitude of the hitting sound, the movable core contacts the stator. It is described that the first member includes a first member and a second member that continues to move after the first member contacts the stator. In this configuration, although the kinetic energy of the movable core (first member) when contacting the stator can be kept small, there is a limit to keep the kinetic energy small, so the movable core (first The striking sound when the member is in contact with the stator cannot be sufficiently suppressed.

  An object of the present invention is to provide a high-pressure fuel pump that can reduce operating noise.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A high-pressure fuel pump that solves the above problem includes an electromagnetic valve whose valve body opens and closes when the movable core moves in the direction in which the axis extends and moves toward or away from the stator. Controls the amount of fuel pumped to the injection valve. The high-pressure fuel pump includes an arm that is formed so as to extend in the moving direction of the movable core and is supported by the housing of the solenoid valve so as to swing in the moving direction. A first contact portion is formed on one end side of the arm with respect to the position of the arm supported by the housing, and the other end of the arm is located at a position of the arm supported by the housing. A second contact portion is formed on the side. The movable core is formed with a first contact surface that contacts the first contact portion of the arm and a second contact surface that contacts the second contact portion of the arm. At least one of the first contact surface and the second contact surface is inclined as follows with respect to the axis of the movable core. That is, when the distance from the axis of the movable core to the contact between the first contact portion and the first contact surface is X1, and the distance from the axis to the contact between the second contact portion and the second contact surface is X2, At least one of the first contact surface and the second contact surface, the distance away from the stator, the longer the distance to the axis is, so that the total value of the distance X1 and the distance X2 increases as the movable core approaches the stator. It has an inclined surface.

  According to the above configuration, the movable core is a stator in a state where the first contact portion of the arm is in contact with the first contact surface of the movable core and the second contact portion of the arm is in contact with the second contact surface of the movable core. Since the total value of the distance X1 and the distance X2 increases with the approach, the first contact portion is pushed by the first contact surface and the second contact portion is pushed by the second contact surface. As a result, a frictional force is generated between the first contact portion and the first contact surface and between the second contact portion and the second contact surface. These frictional forces become resistance when the movable core moves in the approaching direction with respect to the stator, and the moving speed of the movable core is reduced. Therefore, the generation of hitting sound due to the contact of the movable core with the stator is suppressed. . Thus, the operation noise of the high-pressure fuel pump when the fuel is pumped to the fuel injection valve can be reduced by the amount of occurrence of the hitting sound.

Sectional drawing which shows a high pressure fuel pump. Sectional drawing which expands and shows the solenoid valve of a high pressure fuel pump. Sectional drawing which expands and shows the same solenoid valve. Sectional drawing which expands and shows the same solenoid valve. The schematic diagram for demonstrating the inclination of a 1st contact surface and a 2nd contact surface. (A)-(c) is the time which shows the change of the control current at the time of energizing the coil of the stator with the passage of time, the change of the pressure of the fuel in the pressurizing chamber, and the change of the vibration of the housing in the electromagnetic valve chart. The schematic diagram for demonstrating the other example of the inclination of a 1st contact surface and a 2nd contact surface. The schematic diagram for demonstrating the other example of the inclination of a 1st contact surface and a 2nd contact surface.

Hereinafter, an embodiment of a high-pressure fuel pump will be described with reference to FIGS.
As shown in FIG. 1, the plunger 3 is accommodated in the cylinder 1 provided in the body 2 of the high-pressure fuel pump so that the plunger 3 can move up and down. A lifter 4 is fixed to the base end (lower end in the figure) of the plunger 3. The lower end surface of the lifter 4 is in contact with a drive cam 7 fixed to the intake camshaft 6 of the internal combustion engine, and the lifter 4 is urged by a spring 5 in a direction toward the drive cam 7. Then, when the drive cam 7 rotates, the nose portion 8 of the drive cam 7 pushes up the lifter 4 against the urging force of the spring 5 to raise the plunger 3. Further, after the lifter 4 is pushed up by the nose portion 8, the lifter 4 is pushed down by the urging force of the spring 5, and the plunger 3 is lowered. Thus, the plunger 3 periodically moves up and down in the cylinder 1 as the drive cam 7 rotates.

  A pulsation damper 11 is provided in the high-pressure fuel pump. The interior of the pulsation damper 11 is partitioned into a liquid chamber 15 and a gas chamber 16 by a diaphragm 14. The liquid chamber 15 of the pulsation damper 11 is connected to a low pressure fuel passage that receives fuel supplied from the low pressure fuel pump. Further, the liquid chamber 15 is connected to the pressurizing chamber 9 defined by the plunger 3 in the cylinder 1 of the high-pressure fuel pump through a suction passage 21. The suction passage 21 is in a communicating state that allows fuel to flow between the liquid chamber 15 and the pressurizing chamber 9 through the opening of the electromagnetic valve 10 provided in the high-pressure fuel pump. The closed state prohibits the flow of fuel between the liquid chamber 15 and the pressurizing chamber 9 through the valve closing. The pressurizing chamber 9 is connected to a discharge passage 12 formed in the body 2. The discharge passage 12 is connected to a high-pressure fuel passage through a check valve 13, and the high-pressure fuel passage is connected to a fuel injection valve of the internal combustion engine. The check valve 13 allows fuel to flow from the pressurizing chamber 9 to the high pressure fuel passage, while prohibiting fuel from flowing from the high pressure fuel passage to the pressurizing chamber 9.

  When the plunger 3 of the high-pressure fuel pump periodically moves up and down and the solenoid valve 10 is opened (the communication state of the suction passage 21) and the plunger 3 is lowered, the fuel in the low-pressure fuel passage becomes the liquid chamber 15 and the suction passage. The air is sucked into the pressurizing chamber 9 through 21. Thereafter, when the solenoid valve 10 is closed when the plunger 3 is raised (when the suction passage 21 is shut off), the fuel in the pressurizing chamber 9 is pressurized and the fuel in the pressurizing chamber 9 and the discharge passage 12 is pressurized. The pressure increases. As the pressure of the fuel rises, the check valve 13 opens to discharge (pressure-feed) the fuel whose pressure in the pressurizing chamber 9 and the discharge passage 12 is increased to the high-pressure fuel passage. The amount of fuel discharged from the pressurizing chamber 9 and the discharge passage 12 to the high-pressure fuel passage as the plunger 3 is raised is controlled by adjusting the closing timing of the electromagnetic valve 10 during the raising process of the plunger 3. . That is, the earlier the electromagnetic valve 10 closing timing in the ascending process of the plunger 3, the greater the amount of fuel discharged into the high pressure fuel passage. On the other hand, the amount of fuel discharged into the high-pressure fuel passage is reduced as the opening timing of the electromagnetic valve 10 in the ascending process of the plunger 3 is delayed.

  Incidentally, if the solenoid valve 10 is opened while the plunger 3 is raised, the fuel in the pressurizing chamber 9 is returned to the low-pressure fuel passage via the suction passage 21 and the liquid chamber 15 as the plunger 3 is raised. If the fuel in the pressurizing chamber 9 is periodically returned to the low pressure fuel passage as the plunger 3 periodically moves up and down, pressure pulsation may occur in the low pressure fuel passage. However, the occurrence of such pressure pulsation is suppressed through the volume change of the liquid chamber 15 and the gas chamber 16 due to the deflection of the diaphragm 14 of the pulsation damper 11.

Next, the configuration of the electromagnetic valve 10 provided in the high-pressure fuel pump will be described with reference to FIGS.
As shown in FIG. 2, a valve chamber 31 is formed next to the pressurizing chamber 9 in the body 2 of the high-pressure fuel pump. A stopper 33 is provided inside the valve chamber 31. The stopper 33 is formed with a flow hole 34 for connecting the pressurizing chamber 9 and the inside of the valve chamber 31. The housing 18 of the electromagnetic valve 10 is fixed to the body 2 of the high-pressure fuel pump so as to be adjacent to the valve chamber 31. The housing 18 is formed with a communication hole 27 extending in the left-right direction in the drawing and connected to the valve chamber 31, and extending in the vertical direction in the drawing to the communication hole 27 and the liquid chamber 15 of the pulsation damper 11. An introduction hole 28 to be connected is formed. The flow passage 34, the valve chamber 31, the communication hole 27, and the introduction hole 28 form the suction passage 21 for connecting the pressurizing chamber 9 and the liquid chamber 15 of the pulsation damper 11.

  A housing recess 22 is formed in the housing 18 of the electromagnetic valve 10 so as to be recessed in the right direction from the left surface of the housing 18 in the figure. An opening end 27b opposite to the opening end 27a on the valve chamber 31 side of the communication hole 27 is located on the bottom surface (the inner surface on the right side in the figure) of the housing recess 22. The electromagnetic valve 10 includes a movable core 20 provided in the housing recess 22, a needle 26 protruding from the movable core 20 toward the opening end 27 b of the communication hole 27 and inserted into the communication hole 27, and a valve chamber 31. And a valve body 30 located on the same axis as the needle 26. The valve body 30 is formed separately from the needle 26. The valve body 30 is urged toward the needle 26 side (left side in the figure) by a spring 32. The valve body 30 can close or open the opening end 27 a of the communication hole 27. A seal member 29 is provided in a portion closer to the housing recess 22 than a portion connected to the introduction hole 28 in the communication hole 27, and the needle 26 passes through the seal member 29. The seal member 29 prevents the fuel in the communication hole 27 closer to the introduction hole 28 than the seal member 29 from flowing to the opening end 27 b side of the seal member 29.

  The movable core 20 is supported on the housing 18 by a buffer mechanism 23 provided between the movable core 20 and the inner wall of the housing recess 22. A plurality of the buffer mechanisms 23 are provided at equal intervals around the axis of the needle 26. A stator 17 having a coil 19 on the outer periphery is fixed to the opening of the housing recess 22 in the housing 18. The movable core 20 is urged by a spring 25 in a direction away from the stator 17 (right direction in FIG. 2), that is, a direction in which the needle 26 is displaced toward the valve body 30. The biasing force of the spring 25 is set to be larger than the biasing force of the spring 32 acting on the valve body 30. Therefore, in a state where the energization of the coil 19 of the stator 17 is stopped, the movable core 20 is separated from the stator 17 by the urging force of the spring 25, and the needle 26 extending from the movable core 20 is attached to the valve element 30 by the spring 32. Press against the stopper 33 against the force. In this state, the valve body 30 opens the opening end 27 a of the communication hole 27, so that the suction passage 21 is in a communication state in which fuel can flow between the liquid chamber 15 and the pressurization chamber 9.

  FIG. 3 shows the operating state of the solenoid valve 10 when the coil 19 of the stator 17 is energized. Due to the electromagnetic force generated between the stator 17 and the movable core 20 during energization, the movable core 20 is attracted to the stator 17 side (left side in the drawing) against the urging force of the spring 25 and comes into contact with the stator 17. . At that time, the valve body 30 is separated from the stopper 33 by the urging force of the spring 32 and is pressed against the opening end 27a of the communication hole 27, and is separated from the needle 26 at the position at that time. In this state, the valve body 30 closes the opening end 27 a, so that the suction passage 21 is in a shut-off state in which fuel does not flow between the liquid chamber 15 and the pressurizing chamber 9. When the coil 19 is switched from the energized state to the non-energized state, the needle 26 extending from the movable core 20 moves as shown in FIG. 4 as the movable core 20 moves away from the stator 17. After contacting the body 30, the valve body 30 is pressed against the stopper 33 as shown in FIG. When the coil 19 is switched from the non-energized state to the energized state, the movable core 20 at the position shown in FIG. 2 moves in a direction approaching the stator 17, and accordingly, the movable core 20, the needle 26, The valve body 30 changes to the state shown in FIG. 4 and further to the state shown in FIG.

  Thus, in the electromagnetic valve 10, the movable core 20 extends in the direction in which the axis L <b> 1 extends with respect to the stator 17 through control of electromagnetic force generated between the stator 17 and the movable core 20, that is, energization control on the coil 19 of the stator 17. It moves in the direction of the center line of the movable core 20. Thus, when the movable core 20 moves in the direction in which the axis L1 extends, that is, when the movable core 20 approaches or separates from the stator 17, the opening end 27a of the communication hole 27 by the valve body 30 is reduced. Opening and closing operations are performed. The movable core 20 is supported by the housing 18 by the buffer mechanism 23 so that the above-described movement can be performed. The buffer mechanism 23 has a function of reducing the moving speed of the movable core 20 approaching the stator 17 in order to suppress the hitting sound when the movable core 20 contacts the stator 17.

Next, the detailed structure of the buffer mechanism 23 will be described.
As shown in FIG. 2, the buffer mechanism 23 includes a fulcrum portion 41 provided in the housing 18 and an arm 42 supported by the fulcrum portion 41 and extending in the moving direction of the movable core 20. The arm 42 can swing in the moving direction of the movable core 20 around the fulcrum portion 41. A first contact portion 43 is formed on one end side of the arm 42 from the support position of the arm 42 by the fulcrum portion 41, and the other end of the arm 42 is supported by the arm 42 from the support position of the fulcrum portion 41. A second contact portion 44 is formed on the end portion side. In this example, the first contact portion 43 is formed at the end portion of the arm 42 on the stator 17 side, and the second contact portion 44 is formed at the end portion of the arm 42 on the valve body 30 side.

  The movable core 20 has a first contact surface 45 corresponding to the first contact portion 43 of the arm 42 and a second contact surface 46 corresponding to the second contact portion 44 of the arm 42. Yes. The first contact surface 45 and the second contact surface 46 are provided on the arm 42 until the movable core 20 moves from a position where the movable core 20 abuts against the stator 17 (FIG. 3) to a position separated from the stator 17 by a predetermined distance. Both the contact between the first contact portion 43 and the first contact surface 45 and the contact between the second contact portion 44 of the arm 42 and the second contact surface 46 are performed.

  In this embodiment, the position where the movable core 20 is separated from the stator 17 by a predetermined distance is a position closer to the stator 17 than the position (FIG. 2) farthest from the stator 17 in the moving range of the movable core 20. It has become. In this case, the contact between the first contact portion 43 and the first contact surface 45 and the contact between the second contact portion 44 and the second contact surface 46 are only in the portion near the stator 17 in the moving range of the movable core 20. Both will be done. Note that the position (FIG. 3) farthest from the stator 17 in the moving range of the movable core 20 may be adopted as the position where the movable core 20 described above is separated from the stator 17 by a predetermined distance. In this case, both the contact between the first contact portion 43 and the first contact surface 45 and the contact between the second contact portion 44 and the second contact surface 46 are performed over the entire moving range of the movable core 20. Become.

  The first contact surface 45 and the second contact surface 46 are also formed as follows. That is, as shown in FIG. 5, the first contact portion 43 and the first contact surface 45 are in contact with each other, and the second contact portion 44 and the second contact surface 46 are in contact with each other. The distance from the axis L1 to the contact P1 between the first contact portion 43 and the first contact surface 45 is X1, and the distance from the axis L1 to the contact P2 between the second contact portion 44 and the second contact surface 46 is X2. To do. Then, as the movable core 20 approaches the stator 17, at least one of the first contact surface 45 and the second contact surface 46 is separated from the stator 17 so that the total value of the distance X1 and the distance X2 increases. The inclined surface has a longer distance to the axis L1.

  In this example, both the first contact surface 45 and the second contact surface 46 are inclined surfaces in which the distance from the stator 17 (the portion on the right side in the drawing) to the axis L1 becomes longer. Specifically, by forming the portion of the movable core 20 corresponding to the first contact surface 45 in a tapered shape that increases in diameter as it moves away from the stator 17 in the moving direction of the movable core 20 (left and right in the figure). The first contact surface 45 is an inclined surface in which the distance to the axis L <b> 1 becomes longer as it is away from the stator 17. Further, the portion corresponding to the second contact surface 46 in the movable core 20 is formed in a taper shape with a diameter increasing toward the position away from the stator 17 in the moving direction of the movable core 20 (left-right direction in the figure). The two contact surfaces 46 are also inclined surfaces in which the distance from the axis L1 increases as the distance from the stator 17 increases.

Next, the operation of the high pressure fuel pump will be described.
6, (a) to (c) are changes in control current when energizing the coil 19 of the stator 17 over time, changes in the pressure of fuel in the pressurizing chamber 9, and the solenoid valve 10, respectively. The change of the vibration of the housing 18 is shown.

  In the stroke (intake stroke) in which the plunger 3 of the high-pressure fuel pump is lowered, the energization of the coil 19 of the stator 17 in the solenoid valve 10 is not performed, and the valve body 30 of the solenoid valve 10 opens the communication hole 27 as shown in FIG. The end 27a is opened. At this time, as the plunger 3 descends, fuel is sucked into the pressurizing chamber 9 from the liquid chamber 15 and the suction passage 21 connected to the low pressure fuel passage. Thereafter, the process moves to a stroke (discharging stroke) in which the plunger 3 rises, but when the coil 19 is not energized in the discharging stroke, the valve body 30 opens the opening end 27a of the communication hole 27. As the plunger 3 moves up, the fuel in the pressurizing chamber 9 is returned to the liquid chamber 15 through the suction passage 21.

  When the coil 19 is energized in the discharge stroke and the control current at that time increases as shown by the solid line after the timing T1 in FIG. 6A, the movable core 20 approaches the stator 17 as shown in FIG. The valve body 30 closes the open end 27a of the communication hole 27, while abutting against the stator 17. When the opening end 27a is thus closed by the valve body 30, the pressure of the fuel in the pressurizing chamber 9 rises as shown by the solid line after the timing T1 in FIG. . When the check valve 13 shown in FIG. 1 is opened due to such an increase in the pressure of the fuel, the high-pressure fuel in the pressurizing chamber 9 and the discharge passage 12 is pumped to the high-pressure fuel passage (fuel injection valve).

  After the fuel is discharged from the pressurizing chamber 9, when the control current is reduced to "0" as shown by the solid line in FIG. At timing T2, the movable core 20 moves toward the valve body 30 as shown in FIG. 4 and the needle 26 comes into contact with the valve body 30. Thereafter, as the plunger 3 descends during the suction stroke, the pressure of the fuel in the pressurizing chamber 9 decreases as shown by the solid line after timing T2 in FIG. 6B. As the fuel pressure in the pressurizing chamber 9 decreases, the force that presses the valve element 30 against the opening end 27a of the communication hole 27 decreases, and the urging force of the spring 25 increases beyond that force (timing T3). As shown in FIG. 2, the movable core 20 moves away from the stator 17, and the needle 26 presses the valve body 30 against the stopper 33. As a result, the valve body 30 opens the opening end 27a of the communication hole 27, and the fuel is sucked into the pressurizing chamber 9 from the liquid chamber 15 and the suction passage 21 as the plunger 3 descends.

  By repeating the above operation, fuel is discharged from the high pressure fuel pump into the high pressure fuel passage. The amount of fuel discharged from the high-pressure fuel pump into the high-pressure fuel passage is controlled by adjusting the timing at which the valve body 30 closes the opening end 27a of the communication hole 27 in the discharge stroke in which the plunger 3 moves up. . That is, if the opening end 27a is closed by the valve body 30 at an early stage of the ascending process of the plunger 3, the amount of fuel discharged to the high pressure fuel passage increases, and the fuel discharged to the high pressure fuel passage increases as the closing timing is delayed. The amount of.

Further, when the movable core 20 in the high-pressure fuel pump comes into contact with the stator 17, the buffer mechanism 23 operates as follows to reduce the moving speed of the movable core 20.
When the movable core 20 approaches the stator 17 from the state where the movable core 20 is located farthest from the stator 17 as shown in FIG. 2, the first contact portion 43 is pushed by the first contact surface 45 in the example of FIG. The arm 42 swings around the fulcrum portion 41. As the arm 42 swings, the second contact portion 44 is pressed against the second contact surface 46 of the movable core 20 and the first contact portion 43 is also pressed against the first contact surface 45 of the movable core 20. A frictional force is generated between the contact portion 44 and the second contact surface 46 and between the first contact portion 43 and the first contact surface 45. When the movable core 20 further approaches the stator 17 in this state, the total value of the distance X1 and the distance X2 increases with the approach, and the first contact portion 43 is further pushed by the first contact surface 45. The second contact portion 44 is also pushed by the second contact surface 46. As a result, a larger frictional force is generated between the first contact portion 43 and the first contact surface 45 and between the second contact portion 44 and the second contact surface 46. Such a frictional force becomes a resistance when the movable core 20 moves in the approaching direction with respect to the stator 17, and the moving speed of the movable core 20 decreases.

  Note that when the second contact portion 44 is pressed against the second contact surface 46 and the first contact portion 43 is pressed against the first contact surface 45, the arm 42 is applied by the force received from the second contact surface 46 and the first contact surface 45. Will bend. Further, as the movable core 20 approaches the stator 17 (FIG. 2 → FIG. 4 → FIG. 3), the force by which the second contact portion 44 is pressed against the second contact surface 46, and the first contact portion 43 becomes the first contact surface. The force pressed against 45 increases. Therefore, the frictional force acting between the second contact portion 44 and the second contact surface 46 and the friction force acting between the first contact portion 43 and the first contact surface 45 are also caused by the movable core 20 acting on the stator 17. The closer it is, the larger the resistance becomes, and the greater the resistance when the movable core 20 moves in the approaching direction with respect to the stator 17 due to these frictional forces. Thereby, the moving speed of the movable core 20 can be gradually reduced as the movable core 20 approaches the stator 17.

  Thus, since the moving speed of the movable core 20 when abutting against the stator 17 can be reduced, the generation of hitting sound when the movable core 20 abuts against the stator 17 is suppressed. The magnitude of the hitting sound at this time is related to the magnitude of the vibration of the housing 18 of the electromagnetic valve 10 caused by the movable core 20 coming into contact with the stator 17, and the above-mentioned hitting sound increases as the vibration increases. . If the electromagnetic valve 10 does not have the buffer mechanism 23, when the movable core 20 contacts the stator 17 (timing T1 in FIG. 6C), the moving speed of the movable core 20 is decreased by the buffer mechanism 23. Therefore, the vibration of the housing 18 increases as shown by a two-dot chain line in FIG. However, by providing the electromagnetic valve 10 with the buffer mechanism 23, when the movable core 20 contacts the stator 17, the vibration of the housing 18 is suppressed to a small level as shown by the solid line in FIG.

According to the embodiment described in detail above, the following effects can be obtained.
(1) The operation noise of the high-pressure fuel pump when the fuel is pumped to the fuel injection valve can be reduced by the amount of occurrence of the hitting sound when the movable core 20 contacts the stator 17 by the buffer mechanism 23.

  (2) In the buffer mechanism 23, when the movable core 20 approaches the stator 17, the second contact portion 44 is pressed against the second contact surface 46 and the first contact portion 43 is pressed against the first contact surface 45. At this time, the arm 42 is bent by the force received from the second contact surface 46 and the first contact surface 45. Then, depending on the ease of bending of the arm 42 at this time, the magnitude of the frictional force acting between the second contact portion 44 and the second contact surface 46, and the first contact portion 43 and the first contact surface 45. The magnitude of the friction force acting in between changes, and the manner in which the moving speed of the movable core 20 approaching the stator 17 due to the friction force decreases is also changed. In order to suppress the generation of a hitting sound when the movable core 20 comes into contact with the stator 17, the moving speed of the movable core 20 at that time must be appropriately reduced. This can be realized by adjusting the ease of bending of the arm 42 by changing the length of the arm 42 in the direction. Further, the adjustment of the flexibility of the arm 42 can be performed separately from the formation of the movable core 20. Therefore, when performing the adjustment work for suppressing the generation of a hitting sound when the movable core 20 abuts against the stator 17, the adjustment work is easily performed because the formation of the movable core 20 is not involved in the adjustment work. Thus, the electromagnetic valve 10 can be easily manufactured.

  (3) The second contact surface 46 of the movable core 20 is formed in a tapered shape whose diameter increases as the position is farther from the stator 17. For this reason, when energization of the coil 19 of the stator 17 is stopped, the movable core 20 can be easily moved away from the stator 17.

  (4) The valve body 30 of the electromagnetic valve 10 is formed separately from the needle 26 extending from the movable core 20, and when the movable core 20 contacts the stator 17, the movable core 20 and the needle 26 are connected to the valve body 30. It is supposed to be in a separated state. Therefore, the kinetic energy of the movable core 20 at the time of the contact can be reduced.

In addition, the said embodiment can also be changed as follows, for example.
-The 1st contact part 43 does not necessarily need to be formed in the edge part of the arm 42, and may be formed in the part near the support position by the fulcrum part 41 in the arm 42 rather than the edge part. Also, the second contact portion 44 is not necessarily formed at the end portion of the arm 42, and may be formed at a portion closer to the support position by the fulcrum portion 41 in the arm 42 than the end portion.

  Even if the inclination of the first contact surface 45 and the second contact surface 46 is appropriately changed under the condition that the total value of the distance X1 and the distance X2 increases as the movable core 20 approaches the stator 17 Good.

  For example, as shown in FIG. 7, one of the first contact surface 45 and the second contact surface 46 (in this example, the second contact surface 46) is a cylindrical surface parallel to the axis L <b> 1 of the movable core 20. You may form as follows.

Further, as shown in FIG. 8, one of the first contact surface 45 and the second contact surface 46 (in this example, the second contact surface 46) is formed in a tapered shape with a diameter decreasing toward the right side in the figure. May be.
The first contact surface 45 and the second contact surface 46 do not necessarily need to be tapered, and the condition that the total value of the distance X1 and the distance X2 increases as the movable core 20 approaches the stator 17 is satisfied. While being established, at least one of the first contact surface 45 and the second contact surface 46 may be a flat slope, or one of them may be a plane parallel to the axis L1.

  The movable core 20 does not necessarily need to be in contact with the stator 17. That is, when the movable core 20 is closest to the stator 17, the first contact surface 45 and the second contact surface 46 are adjusted in inclination so that a gap is formed between the stator 17 and the movable core 20, and You may adjust the ease of bending of the arm 42. FIG.

  The valve body 30 of the electromagnetic valve 10 may be formed integrally with the needle 26 extending from the movable core 20.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder, 2 ... Body, 3 ... Plunger, 4 ... Lifter, 5 ... Spring, 6 ... Intake cam shaft, 7 ... Drive cam, 8 ... Nose part, 9 ... Pressurization chamber, 10 ... Solenoid valve, 11 ... Pal Suction damper, 12 ... discharge passage, 13 ... check valve, 14 ... diaphragm, 15 ... liquid chamber, 16 ... gas chamber, 17 ... stator, 18 ... housing, 19 ... coil, 20 ... movable core, 21 ... suction passage, 22 ... accommodation recess, 23 ... buffer mechanism, 25 ... spring, 26 ... needle, 27 ... communication hole, 27a ... open end, 27b ... open end, 28 ... introduction hole, 29 ... sealing member, 30 ... valve element, 31 ... Valve chamber, 32 ... spring, 33 ... stopper, 34 ... flow hole, 41 ... fulcrum part, 42 ... arm, 43 ... first contact part, 44 ... second contact part, 45 ... first contact surface, 46 ... second Contact surface.

Claims (1)

An electromagnetic valve that opens and closes the valve body by moving the movable core in the direction in which the axis extends and moving toward or away from the stator, and controls the amount of fuel pumped to the fuel injection valve by the electromagnetic valve A high-pressure fuel pump,
An arm that is formed to extend in the moving direction of the movable core and is supported by the housing of the solenoid valve so as to swing in the moving direction;
A first contact portion formed on one end side of the arm from a position of the arm supported by the housing;
A second contact portion formed on the other end side of the arm with respect to a position of the arm supported by the housing;
A first contact surface formed on the movable core and in contact with the first contact portion;
A second contact surface formed on the movable core and in contact with the second contact portion;
With
The distance from the axis of the movable core to the contact between the first contact portion and the first contact surface is X1, and the distance from the axis to the contact between the second contact portion and the second contact surface is X2. In this case, at least one of the first contact surface and the second contact surface is separated from the stator such that the total value of the distance X1 and the distance X2 increases as the movable core approaches the stator. A high-pressure fuel pump characterized in that the inclined surface has a long distance to the axis.