JP2022067509A - Fuel supply pump - Google Patents

Abstract

To provide a fuel supply pump which can suppress the production of abrasion powder by a simple constitution.SOLUTION: A shaft 20 has a drive groove 23 which is recessed inwards in a radial direction from an external peripheral wall at one end in an axial direction. A low-pressure pump 30 comprises a key 40, an outer tooth gear 50, a housing 70 and movement regulation parts 80, 81. The key 40 is arranged in the drive groove 23 so as to be relatively movable to the shaft 20. The outer tooth gear 50 has a driven groove 53 which is annularly formed so that one end of the shaft 20 is located inside and recessed outwards in the radial direction from the inner peripheral wall, and into which the key 40 is fit. The outer tooth gear rotates integrally with the shaft 20 via the key 40, sucks fuel by changing a volume of a space 500 between an inner tooth gear 60 and itself, and supplies the fuel to a high-pressure pump. The housing 70 relatively rotatably accommodates the outer tooth gear 50. The movement regulation parts 80, 81 are formed at the outer tooth gear 50 or the shaft 20, respectively, and can regulate the movement of the key 40 in the axial direction of the shaft 20.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fuel supply pump.

Conventionally, it is equipped with a high-pressure pump that pressurizes fuel and supplies it to an internal combustion engine, a low-pressure pump that supplies fuel to the high-pressure pump, and a shaft that rotates by the driving force of the internal combustion engine and can pressurize fuel in the high-pressure pump. Fuel supply pumps are known.

For example, in the fuel supply pump of Patent Document 1, a groove is formed at one end of the shaft, a through groove is formed on the inner circumference of the rotating member of the low pressure pump, and one key is provided for the groove of the shaft and the through groove of the rotating member. The shaft and the rotating member are integrally rotated via the key. Here, the rotating member and the key are housed in the housing.

In a fuel supply pump as in Patent Document 1, the key may move in the axial direction with respect to the shaft and come into contact with the inner wall of the housing that rotates relative to the shaft. If the key and the housing are in contact with each other and the two rotate relative to each other, wear debris may be generated, which may lead to mixing in fuel or biting between parts.

JP 2015-161206A

Therefore, in the fuel supply pump of Patent Document 1, a hole is formed in the groove of the shaft, a key hole is formed in the key, and one pin is fitted into the hole of the shaft and the key hole of the key. This pin regulates the relative movement of the key with respect to the shaft. As a result, the contact between the relative rotating key and the housing is suppressed, and the generation of wear debris is suppressed.

However, in the fuel supply pump of Patent Document 1, a pin is required to regulate the relative movement between the key and the shaft, and the number of members increases. Further, in order to provide the pin, it is necessary to form a hole in the groove of the shaft and a key hole in the key, which increases the processing man-hours. Further, since it is necessary to fit the pin into the hole of the shaft and the key hole of the key, the assembly man-hours increase. In addition, it is necessary to properly control the dimensions of the pin, shaft hole and key hole of the key.

An object of the present invention is to provide a fuel supply pump capable of suppressing the generation of wear debris with a simple configuration.

The fuel supply pump according to the present invention includes a high-pressure pump (10), a low-pressure pump (30), and a shaft (20). The high-pressure pump pressurizes the fuel and discharges it to the outside. The low pressure pump supplies fuel to the high pressure pump. The shaft has a drive groove (23) recessed radially inward from the outer peripheral wall at one end in the axial direction, and can pressurize fuel in a high-pressure pump by rotating.

The low pressure pump includes a key (40), a rotating member (50), a housing (70), and a movement control unit (80, 81, 82, 83). The key is provided in the drive groove so that it can move relative to the shaft. The rotating member is formed in an annular shape so that one end of the shaft is located inside, has a driven groove (53) into which a key is recessed radially outward from the inner peripheral wall, and rotates integrally with the shaft via the key. By changing the volume of the space (500) between the other member (60), fuel is sucked and supplied to the high-pressure pump.

The housing houses the rotating members so that they can rotate relative to each other. The movement restricting unit is formed on at least one of the rotating member or the shaft, and can regulate the movement of the key in the axial direction of the shaft.

In the present invention, the movement of the key in the axial direction of the shaft can be regulated by the rotating member that rotates integrally with the shaft or the movement restricting portion formed on the shaft. As a result, it is possible to suppress the key from coming into contact with the housing that rotates relative to the key, and to suppress the generation of wear debris due to the contact between the key and the housing and the relative rotation. Further, since the area of the sliding surface between the rotating member and the housing is larger than the area of the contact surface when the key and the housing come into contact with each other, the surface pressure acting on the housing is reduced and the housing is worn. Can be suppressed.

Further, unlike the conventional technique (Patent Document 1), a pin for restricting the relative movement between the shaft and the key is not required, so that the number of member points, processing man-hours, and assembly man-hours can be reduced, and a simple configuration can be achieved. can.

The schematic diagram which shows the common rail system which applied the fuel supply pump by 1st Embodiment. The cross-sectional view which shows the fuel supply pump by 1st Embodiment. The cross-sectional view which shows the low pressure pump of the fuel supply pump by 1st Embodiment. FIG. 3 is a sectional view taken along line IV-IV of FIG. The cross-sectional view which shows the low pressure pump of the fuel supply pump by the comparative form. The cross-sectional view which shows the low pressure pump of the fuel supply pump by 2nd Embodiment. The cross-sectional view which shows the low pressure pump of the fuel supply pump by 3rd Embodiment. The cross-sectional view which shows the low pressure pump of the fuel supply pump by 4th Embodiment. FIG. 5 is a cross-sectional view showing a low pressure pump of a fuel supply pump according to a fifth embodiment. FIG. 6 is a cross-sectional view showing a low pressure pump of a fuel supply pump according to a sixth embodiment. FIG. 5 is a cross-sectional view showing a low pressure pump of a fuel supply pump according to a seventh embodiment.

Hereinafter, fuel supply pumps according to a plurality of embodiments will be described with reference to the drawings. In the plurality of embodiments, substantially the same constituent parts are designated by the same reference numerals, and the description thereof will be omitted.

(First Embodiment)
FIG. 1 shows a fuel supply pump according to the first embodiment and a common rail system to which the pump is applied.

The common rail system is mounted on a vehicle (not shown), for example, and is used to supply fuel to an internal combustion engine (hereinafter referred to as "engine") 2 mounted on the vehicle. Here, the engine 2 is, for example, a diesel engine.

As shown in FIG. 1, the common rail system includes a fuel supply pump 1, a fuel tank 3, a fuel filter 4, a common rail 5, a plurality of fuel injection valves 6, and the like.

The fuel tank 3 stores fuel. The fuel filter 4 is provided in the middle of the low-pressure fuel pipe 7 connecting the fuel tank 3 and the fuel supply pump 1, and collects foreign substances in the fuel flowing from the fuel tank 3 to the fuel supply pump 1.

The fuel supply pump 1 and the common rail 5 are connected by a high-pressure fuel pipe 8. The common rail 5 and the plurality of fuel injection valves 6 are connected by a plurality of high-pressure fuel pipes 9. The fuel supply pump 1 pressurizes the fuel sucked from the fuel tank 3 and supplies the high-pressure fuel to the common rail 5.

The high-pressure fuel supplied to the common rail 5 is distributed to a plurality of (four in this embodiment) fuel injection valves 6. The fuel injection valve 6 injects fuel into the cylinder of the engine 2. The fuel that is not supplied to the downstream side in the fuel supply pump 1, the common rail 5 or the fuel injection valve 6 or is not consumed by the injection is returned to the fuel tank 3 via the return pipe.

An electronic control unit (hereinafter referred to as “ECU”) 100 is connected to the fuel supply pump 1 and the plurality of fuel injection valves 6. The ECU 100 is a small computer equipped with a CPU, ROM, RAM, I / O, and the like. The ECU 100 controls the operation of devices, devices, and the like mounted on the vehicle based on signals and the like from various sensors provided on the vehicle. This makes it possible to control the operation of the fuel supply pump 1, the fuel injection valve 6, and the like according to the operating conditions of the vehicle and the like.

As shown in FIG. 2, the fuel supply pump 1 includes a pump body 11, a high-pressure pump 10, a low-pressure pump 30, a shaft 20, and the like. The pump body 11 is made of, for example, metal.

The high pressure pump 10 has two cylinders 12, two solenoid valves 13, two plungers 14, two tappets 16, two rollers 17, two return springs 18, and the like.

The two cylinders 12 are formed in a cylindrical shape, for example, from metal, and are provided in each of the two holes formed on the upper surface of the pump body 11. The two solenoid valves 13 are provided at the ends of the two cylinders 12 opposite to the pump body 11. The two plungers 14 are formed in a rod shape, for example, from metal, and are provided so as to be reciprocally movable in the axial direction inside each of the two cylinders 12. Here, a pressurizing chamber 15 whose volume changes with the reciprocating movement of the plunger 14 is formed between the solenoid valve 13 and the plunger 14.

The two tappets 16 are provided to connect to each of the ends of the two plungers 14 opposite the solenoid valve 13. The two rollers 17 are rotatably provided on each of the two tappets 16. The two return springs 18 are provided between the surface of the two cylinders 12 opposite the solenoid valve 13 and the two tappets 16, respectively. The return spring 18 urges the tappet 16 and the roller 17 to the opposite side of the solenoid valve 13.

The low pressure pump 30 is provided on the side surface of the pump body 11. The low pressure pump 30 supplies fuel to the high pressure pump 10. The configuration of the low pressure pump 30 will be described in detail later.

The shaft 20 has a shaft body 21, a cam 22, and the like. The shaft body 21 is formed in a rod shape, for example, by metal. The shaft body 21 is bearing on the pump body 11 at one end side and the other end side in the axial direction so as to be rotatable around the axis. Here, the shaft main body 21 is provided on the pump body 11 so that one end and the other end in the axial direction protrude from the outer wall of the pump body 11.

One end of the shaft body 21 in the axial direction is located in the low pressure pump 30. The other end of the shaft body 21 in the axial direction is connected to the drive shaft of the engine 2. As a result, when the engine 2 rotates, the shaft body 21 also rotates.

Two cams 22 are provided at predetermined intervals in the axial direction of the shaft main body 21 so that they can rotate integrally with the shaft main body 21. Each of the two cams 22 is provided so as to be eccentric with respect to the shaft body 21.

The outer peripheral walls of the two cams 22 are in contact with the outer peripheral walls of the two rollers 17. When the shaft 20 rotates, the plunger 14 reciprocates in the axial direction while the roller 17 rolls on the outer peripheral wall of the cam 22. As a result, the volume of the pressurizing chamber 15 increases or decreases.

A more specific configuration of the shaft 20 will be described in detail later.

The solenoid valve 13 can open and close between the low pressure pump 30 and the pressurizing chamber 15. In the present embodiment, the solenoid valve 13 is closed by energization and closes between the low pressure pump 30 and the pressurizing chamber 15. The solenoid valve 13 is open when it is not energized. That is, the solenoid valve 13 is a normally open type valve device. The ECU 100 is connected to the solenoid valve 13 and can control the operation of the solenoid valve 13 according to the operating condition of the engine 2 and the like.

When the plunger 14 moves from the top dead center side to the bottom dead center side with the rotation of the shaft 20, the volume of the pressurizing chamber 15 increases. At this time, when the solenoid valve 13 is opened, fuel is sucked into the pressurizing chamber 15 from the low pressure pump 30 side. On the other hand, when the plunger 14 moves from the bottom dead center side to the top dead center side, the volume of the pressurizing chamber 15 decreases. At this time, when the solenoid valve 13 is closed, the fuel is pressurized in the pressurizing chamber 15. When the pressure of the fuel in the pressurizing chamber 15 becomes a predetermined value or more, the fuel is discharged from the pressurizing chamber 15 to the high pressure fuel pipe 8 side. The ECU 100 adjusts the amount of fuel sucked into the pressurizing chamber 15 and adjusts the amount of fuel discharged from the high-pressure pump 10 by opening and closing the solenoid valve 13 in accordance with the movement of the plunger 14. Can be done.

In this way, the shaft 20 can pressurize the fuel in the high pressure pump 10 by rotating.

Next, the configurations of the low pressure pump 30 and the shaft 20 will be described in detail.

As shown in FIGS. It is equipped with 81 mag.

The key 40 is formed of, for example, a metal in a rectangular columnar shape.

The outer peripheral wall at one end of the shaft body 21 in the axial direction is formed in a substantially cylindrical surface shape. The shaft 20 has a drive groove 23. The drive groove 23 is formed so as to be recessed inward in the radial direction from the outer peripheral wall at one end in the axial direction of the shaft main body 21. In the present embodiment, the drive groove 23 is formed so as to extend in the axial direction of the shaft 20 from the end face of one end in the axial direction of the shaft main body 21. One drive groove 23 is formed in the circumferential direction of the shaft main body 21. Four wall surfaces of the shaft body 21 forming the drive groove 23 are formed in a plane shape.

Here, for convenience, the four planar wall surfaces of the shaft body 21 forming the drive groove 23 are referred to as wall surface 231, wall surface 232, wall surface 233, and wall surface 234, respectively.

The wall surface 231 is a rectangular wall surface formed at a position separated from the outer peripheral wall of the shaft main body 21 by a predetermined distance and parallel to the axis Ax1 of the shaft 20. The wall surface 232 is a rectangular wall surface that is formed so as to connect the outer peripheral wall of the shaft main body 21 and the wall surface 231 and is parallel to the axis Ax1 of the shaft 20 and perpendicular to the wall surface 231. The wall surface 233 is a rectangular wall surface that is formed so as to connect the outer peripheral wall of the shaft main body 21 and the wall surface 231 and is parallel to the axis Ax1 and the wall surface 232 of the shaft 20 and perpendicular to the wall surface 231. The wall surface 234 is formed so as to connect the outer peripheral wall of the shaft main body 21 and the wall surface 231 and is a substantially rectangular wall surface perpendicular to the shaft Ax1, the wall surface 231 and the wall surface 232 and the wall surface 233 of the shaft 20. Here, "parallel" is used as a term including not only strict parallelism but also substantially parallelism. In addition, "vertical" is not limited to strict vertical, but is used as a term including being generally vertical. The same applies below.

The depth of the drive groove 23 in the radial direction of the shaft body 21, that is, the distance between the outer peripheral wall of the shaft body 21 and the wall surface 231 is smaller than the radius of one end of the shaft body 21 in the axial direction.

<3> The external tooth gear 50 is formed in an annular shape by, for example, metal. In the present embodiment, the external tooth gear 50 is formed, for example, by molding metal powder in a predetermined mold and baking it, that is, by sintering it. The external tooth gear 50 has external teeth 52. Six outer teeth 52 are formed at equal intervals in the circumferential direction at the outer edge portion of the outer tooth gear 50. The external tooth gear 50 is provided on the radial outer side of one end of the shaft body 21 in the axial direction. That is, the external tooth gear 50 is formed in an annular shape so that one end of the shaft 20 in the axial direction is located inside.

The inner peripheral wall of the external tooth gear 50 is formed in a substantially cylindrical surface shape. The inner diameter of the external tooth gear 50 is slightly larger than the outer diameter of one end in the axial direction of the shaft body 21. The external tooth gear 50 can rotate relative to the shaft body 21.

The external tooth gear 50 has a driven groove 53. The driven groove 53 is formed so as to be recessed radially outward from the inner peripheral wall of the external tooth gear 50. In the present embodiment, the driven groove 53 is formed so as to extend in the axial direction of the external tooth gear 50 from the end surface of the external tooth gear 50 on the pump body 11 side. One driven groove 53 is formed in the circumferential direction of the external tooth gear 50. Four wall surfaces of the external tooth gear 50 forming the driven groove 53 are formed in a plane shape.

Here, for convenience, the four planar wall surfaces of the external tooth gear 50 forming the driven groove 53 are referred to as a wall surface 531, a wall surface 532, a wall surface 533, and a wall surface 534, respectively.

The wall surface 531 is a rectangular wall surface formed at a position separated from the inner peripheral wall of the external tooth gear 50 by a predetermined distance and parallel to the axis Ax2 of the external tooth gear 50. The wall surface 532 is a rectangular wall surface that is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 and is parallel to the axis Ax2 of the external tooth gear 50 and perpendicular to the wall surface 531. The wall surface 533 is a rectangular wall surface formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 so as to be parallel to the axis Ax2 of the external tooth gear 50 and the wall surface 532 and perpendicular to the wall surface 531. be. The wall surface 534 is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 and is a substantially rectangular wall surface perpendicular to the shaft Ax2, the wall surface 531 and the wall surface 532 and the wall surface 533 of the external tooth gear 50. ..

The key 40 is provided so as to fit into both the drive groove 23 of the shaft 20 and the driven groove 53 of the external tooth gear 50. Therefore, when the shaft 20 rotates, the external tooth gear 50 rotates integrally with the shaft 20 via the key 40.

Here, the key 40 is movable relative to the shaft 20 and the external tooth gear 50 in the drive groove 23 and the driven groove 53.

<3> The internal tooth gear 60 is formed in an annular shape by, for example, metal. In the present embodiment, the internal tooth gear 60 is formed, for example, by molding metal powder in a predetermined mold and baking it, that is, by sintering it. The internal tooth gear 60 has internal teeth 62. Seven internal teeth 62 are formed at equal intervals in the circumferential direction at the inner edge portion of the internal tooth gear 60. The internal tooth gear 60 is provided on the radial outer side of the external tooth gear 50 so that the internal tooth 62 can mesh with the external tooth 52 of the external tooth gear 50. The outer peripheral wall of the internal tooth gear 60 is formed in a substantially cylindrical surface shape.

<2> The housing 70 has a cover 71 and a plate 72. The cover 71 is made of, for example, metal. The cover 71 has a cover cylinder portion 711 and a cover bottom portion 712. The cover cylinder portion 711 is formed in a substantially cylindrical shape. The inner peripheral wall of the cover cylinder portion 711 is formed in a substantially cylindrical surface shape. The cover bottom portion 712 is integrally formed with the cover cylinder portion 711 so as to close one end of the cover cylinder portion 711. As described above, the cover 71 is formed in the shape of a bottomed cylinder.

The plate 72 is formed of, for example, a metal ring into a plate shape. The plate 72 is provided integrally with the cover 71 so as to close the opening 710 on the side opposite to the cover bottom 712 of the cover 71. The plate 72 closes the opening 710 of the cover 71 to form a substantially columnar storage space 700 between the plate 72 and the cover 71.

The housing 70 is provided so that the surface of the plate 72 opposite to the cover 71 abuts on the side surface of the pump body 11. The housing 70 is fixed to the pump body 11 by bolts 19 (see FIG. 1).

Here, one end of the shaft body 21 in the axial direction is located inside the plate 72 and in the accommodation space 700. The external tooth gear 50, the internal tooth gear 60, and the key 40 are housed in the storage space 700.

The housing 70 has a recess 73. The recess 73 is formed so as to be recessed in a substantially circular shape from the surface of the cover bottom 712 on the plate 72 side to the side opposite to the plate 72. The recess 73 is formed at a position where the center and the axis Ax1 of the shaft 20 substantially coincide with each other. The outer diameter of the recess 73 is larger than the outer diameter of one end of the shaft body 21 in the axial direction.

The outer diameter of the internal tooth gear 60 is slightly smaller than the inner diameter of the cover cylinder portion 711. The shaft Ax3 of the internal gear 60 and the shaft of the cover cylinder portion 711 are eccentric with respect to the shaft Ax1 of the shaft 20.

When the shaft 20 rotates, the external tooth gear 50 rotates via the key 40. As a result, the internal tooth gear 60 that meshes with the external tooth gear 50 rotates around the shaft Ax3 inside the cover cylinder portion 711. At this time, the volume of the space 500 between the external tooth gear 50 and the internal tooth gear 60 changes.

When the volume of the space 500 changes with the rotation of the external tooth gear 50 and the internal tooth gear 60, fuel is sucked into the space 500 from the fuel tank 3 side via the low pressure fuel pipe 7 and the suction port (not shown), which is not shown. Fuel is supplied from the space 500 to the high pressure pump 10 side via the discharge port.

<3> As described above, in the present embodiment, in the low pressure pump 30, the volume of the space 500 between the external teeth 52 and the internal teeth 62 changes due to the rotation of the external tooth gear 50 and the internal tooth gear 60, and the fuel It is an internal gear pump that sucks and discharges.

<7> As shown in FIG. 3, the axial length L1 of the shaft 20 at one end (diametrically inner end) of the key 40 in the radial direction of the shaft 20 is other than the key 40 in the radial direction of the shaft 20. It is the same as the axial length L2 of the shaft 20 at the end (the outer end in the radial direction). Further, L1 and L2 are shorter than the radial length L3 of the shaft 20 of the key 40. As a result, the key 40 has an I-shaped cross section formed by a virtual plane including all the axes Ax1 of the shaft 20.

Here, the distance between the wall surface 531 of the drive groove 23 and the wall surface 531 of the driven groove 53 is slightly larger than that of L3. Therefore, the key 40 is movable relative to the shaft 20 and the external tooth gear 50 in the radial direction of the shaft 20 between the wall surface 231 and the wall surface 531.

Further, the wall surface 234 of the drive groove 23 is located on the cover bottom portion 712 side with respect to the surface of the plate 72 on the cover 71 side. The distance between the wall surface 234 of the drive groove 23 and the wall surface 534 of the driven groove 53 in the axial direction of the shaft 20 is larger than L1 and L2. Therefore, the key 40 is movable relative to the shaft 20 and the external tooth gear 50 in the axial direction of the shaft 20 between the wall surface 234 and the wall surface 534.

<5> The movement restricting portion 80 is formed on the wall surface 534 of the external tooth gear 50. The movement restricting unit 80 can restrict the movement of the key 40 toward the cover bottom portion 712 in the axial direction of the shaft 20 by abutting on the key 40.

The movement restricting portion 81 is formed on the wall surface 234 of the shaft 20. The movement restricting unit 81 can regulate the movement of the key 40 toward the plate 72 in the axial direction of the shaft 20 by abutting on the key 40.

FIG. 5 shows a comparative form. In the comparative embodiment, the driven groove 53 is formed so as to extend from the end surface of the external tooth gear 50 on the pump body 11 side to the end surface on the cover bottom 712 side. Therefore, the driven groove 53 does not have a wall surface 534. Further, the wall surface 234 of the drive groove 23 is located on the side opposite to the cover bottom portion 712 with respect to the surface of the plate 72 on the cover 71 side. The comparative form does not include the movement control unit 80 and the movement control unit 81.

In the comparative embodiment, the key 40 is moved to the cover bottom 712 side by the thrust force generated by the oblique tooth gear provided on the drive shaft of the engine 2 pushing the shaft 20 in the axial direction. Further, when the shaft 20 is pushed by the oblique tooth gear, the key 40 may come into contact with the cover bottom portion 712, and a load may be applied between the key 40 and the cover bottom portion 712. At this time, there is a moment when the torque of the shaft 20 becomes 0, and there is a possibility that prying may occur between the key 40 and the cover bottom portion 712 that rotates relative to each other. As a result, wear powder may be generated or abnormal wear may occur on the cover 71.

Further, when the key 40 moves in the axial direction of the shaft 20 and comes into contact with the plate 72 that rotates relative to each other, wear powder may be generated between the key 40 and the plate 72, or abnormal wear may occur on the plate 72. There is.

On the other hand, in the present embodiment, even if the key 40 moves toward the cover bottom portion 712 due to the thrust force generated by the oblique tooth gear pushing the shaft 20 in the axial direction, the movement restricting portion 80 formed on the external tooth gear 50 causes the key 40 to move. , The movement of the key 40 toward the cover bottom 712 in the axial direction of the shaft 20 can be restricted. As a result, it is possible to suppress the key 40 from coming into contact with the cover bottom 712 of the housing 70 that rotates relative to the key 40, and to suppress the generation of wear debris due to the contact between the key 40 and the cover bottom 712 and the relative rotation. Further, the area of the sliding surface between the external tooth gear 50 and the cover bottom 712 (see FIG. 3) is larger than the area of the contact surface between the key 40 and the cover bottom 712 in the comparative form (see FIG. 5). As compared with the comparative form, the surface pressure acting on the cover bottom portion 712 is reduced, and the wear of the cover bottom portion 712 can be suppressed.

Further, even if the key 40 moves to the plate 72 side, the movement restricting portion 81 formed on the shaft 20 can restrict the movement of the key 40 to the plate 72 side in the axial direction of the shaft 20. As a result, it is possible to suppress the key 40 from coming into contact with the plate 72 of the housing 70 that rotates relative to the key 40, and to suppress the generation of wear debris due to the contact between the key 40 and the plate 72 and the relative rotation.

As described above, <1> the movement restricting unit 80 and the movement restricting unit 81 are formed on the external tooth gear 50 and the shaft 20, respectively, and can regulate the movement of the key 40 in the axial direction of the shaft 20.

In the present embodiment, the movement of the key 40 in the axial direction of the shaft 20 can be restricted by the external tooth gear 50 that rotates integrally with the shaft 20 or the movement restricting unit 80 and the movement restricting unit 81 formed on the shaft 20. .. As a result, it is possible to suppress the key 40 from coming into contact with the housing 70 that rotates relative to the key 40, and to suppress the generation of wear debris due to the contact between the key 40 and the housing 70 and the relative rotation. Further, since the area of the sliding surface between the external tooth gear 50 and the housing 70 is larger than the area of the contact surface when the key 40 and the housing 70 are in contact with each other as in the comparative form, the area of the sliding surface acts on the housing 70. The surface pressure is reduced, and the wear of the housing 70 can be suppressed.

Further, unlike the prior art (Japanese Patent Laid-Open No. 2015-161206), since a pin for restricting the relative movement between the shaft 20 and the key 40 is not required, the number of member points, processing man-hours, and assembly man-hours can be reduced, which is easy. Can be configured as such.

<2> In the present embodiment, the housing 70 has an accommodating space 700 between the cover 71 having an accommodating space 700 accommodating the external tooth gear 50 and the cover 71 by closing the opening 710 of the cover 71. Has a plate 72 to form.

Therefore, the settings can be changed, for example, the cover 71 and the plate 72 are formed of different materials.

<3> In the present embodiment, the external tooth gear 50 has external teeth 52 at the outer edge portion. The internal tooth gear 60 has an internal tooth 62 that can mesh with the external tooth 52 at the inner edge portion. The low pressure pump 30 is an inscribed gear pump in which the volume of the space 500 between the external teeth 52 and the internal teeth 62 changes due to the rotation of the external tooth gear 50, and fuel is sucked in and discharged.

Therefore, the low-pressure pump 30 can be made smaller and can be arranged in a small space as compared with, for example, an external gear pump in which external teeth mesh with each other. In addition, the efficiency of the low pressure pump 30 can be increased.

<5> In the present embodiment, the movement restricting unit 80 and the movement restricting unit 81 are formed on the external tooth gear 50 and the shaft 20, respectively.

Therefore, the external tooth gear 50 that rotates synchronously with the key 40 and the movement restricting unit 80 and the movement restricting unit 81 formed on the shaft 20 come into contact with the key 40 to restrict the movement of the key 40, so that the external tooth gear 50 rotates relative to the key 40. As compared with the case where the housing 70 comes into contact with the key 40 to restrict the movement of the key 40 (comparative form), wear of the key 40 and the like can be suppressed.

<7> In the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the axial length of the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. It is the same as the length L2.

The shape of the key 40 can be simplified and easily manufactured.

(Second Embodiment)
A part of the fuel supply pump of the second embodiment is shown in FIG. In the second embodiment, the configuration of the key 40 and the like are different from those in the first embodiment.

In the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the same as the axial length L2 of the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. Is. Further, L1 and L2 are the same as the radial length L3 of the shaft 20 of the key 40. As a result, the key 40 has a square cross-sectional shape formed by a virtual plane including all the axes Ax1 of the shaft 20.

L1 and L2 of this embodiment are larger than L1 and L2 of the first embodiment. In the present embodiment, as compared with the first embodiment, the area of the contact surface between the key 40 and the wall surface 232 or the wall surface 233 of the drive groove 23, and the contact surface between the key 40 and the wall surface 532 or the wall surface 533 of the driven groove 53. Area can be increased. Therefore, the surface pressure acting on the key 40, the shaft 20, and the external tooth gear 50 can be reduced, and the wear of these members can be suppressed.

(Third Embodiment)
A part of the fuel supply pump of the third embodiment is shown in FIG. The third embodiment is different from the first embodiment in the configuration of the key 40, the drive groove 23 of the shaft 20, and the driven groove 53 of the external tooth gear 50.

In the present embodiment, the axial length of the shaft 20 of the key 40 increases from one end (diametrically inner end) to the other end (diametrically outer end) of the key 40 in the radial direction of the shaft 20. It gradually becomes smaller and is 0 at the other end (diametrically outer end) of the key 40. As a result, the key 40 has a triangular cross-sectional shape formed by a virtual plane including all the axes Ax1 of the shaft 20.

<6> As described above, in the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the axis of the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. Different from the length L2 in the direction. Further, L1 and L3 are the same as L1 and L3 of the first embodiment, respectively. L2 is 0.

<4> In the present embodiment, the wall surface 234 of the drive groove 23 is located on the side opposite to the cover bottom portion 712 with respect to the surface of the plate 72 on the cover 71 side. This embodiment does not include the movement control unit 81 shown in the first embodiment.

In the present embodiment, the wall surface 534 of the driven groove 53 is formed in a rectangular flat shape so as to connect the inner peripheral wall of the external tooth gear 50 and the end surface of the external tooth gear 50 on the plate 72 side. The wall surface 534 is inclined with respect to the axis Ax2 of the external tooth gear 50. In this embodiment, the wall surface 531 is not formed.

The angle of the wall surface 534 with respect to the axis Ax2 of the external tooth gear 50 is substantially the same as the angle between the surface of the key 40 on the plate 72 side and the surface of the cover bottom 712 side.

As described above, in the present embodiment, the key 40 has a triangular cross section formed by a virtual plane including all the axes Ax1 of the shaft 20. Further, L1 and L3 are the same as L1 and L3 of the first embodiment, respectively. Therefore, the mass of the key 40 can be reduced by half and the inertial force can be reduced as compared with the first embodiment. As a result, wear on the contact surface between the key 40 and the external tooth gear 50 and the like can be suppressed.

Further, in the present embodiment, L1 is larger than L2. Therefore, the area of the contact surface between the key 40 and the wall surface 232 or the wall surface 233 of the drive groove 23 can be made larger than the area of the contact surface between the key 40 and the wall surface 532 or the wall surface 533 of the driven groove 53. Thereby, the surface pressure acting on the key 40 and the shaft 20 can be reduced, and the wear of these members can be suppressed.

As described above, <6> In the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of.

Therefore, the mass of the key 40 can be reduced and the inertial force can be reduced. As a result, wear on the contact surface between the key 40 and the external tooth gear 50 and the like can be suppressed. Further, when L1 is made larger than L2 as in the present embodiment, the area of the contact surface between the key 40 and the shaft 20 can be increased, the surface pressure can be reduced, and wear can be suppressed.

(Fourth Embodiment)
A part of the fuel supply pump of the fourth embodiment is shown in FIG. The fourth embodiment is different from the first embodiment in the configuration of the drive groove 23 of the shaft 20 and the driven groove 53 of the external tooth gear 50.

In the present embodiment, the wall surface 234 of the drive groove 23 is located on the side opposite to the cover bottom portion 712 with respect to the surface of the plate 72 on the cover 71 side. This embodiment does not include the movement control unit 81 shown in the first embodiment.

In the present embodiment, the driven groove 53 is formed in a hole shape recessed outward in the radial direction of the external tooth gear 50 at the center of the inner peripheral wall of the external tooth gear 50 in the axial direction. In the present embodiment, five wall surfaces of the external tooth gear 50 forming the driven groove 53 are formed in a plane shape.

Here, for convenience, the five planar wall surfaces of the external tooth gear 50 forming the driven groove 53 are referred to as a wall surface 531 and a wall surface 532, a wall surface 533, a wall surface 534, and a wall surface 535, respectively.

The wall surface 531 is a rectangular wall surface formed at a position separated from the inner peripheral wall of the external tooth gear 50 by a predetermined distance and parallel to the axis Ax2 of the external tooth gear 50. The wall surface 532 is a rectangular wall surface that is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 and is parallel to the axis Ax2 of the external tooth gear 50 and perpendicular to the wall surface 531. The wall surface 533 (not shown) is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 so as to be parallel to the axis Ax2 of the external tooth gear 50 and the wall surface 532 and perpendicular to the wall surface 531. It is a rectangular wall surface. The wall surface 534 is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 and is a substantially rectangular wall surface perpendicular to the shaft Ax2, the wall surface 531 and the wall surface 532 and the wall surface 533 of the external tooth gear 50. .. The wall surface 535 is formed so as to connect the inner peripheral wall of the external tooth gear 50 and the wall surface 531 so as to be perpendicular to the shaft Ax2, the wall surface 531 and the wall surface 532 and the wall surface 533 of the external tooth gear 50 and parallel to the wall surface 534. It is a substantially rectangular wall surface.

The distance between the wall surface 534 and the wall surface 535 of the driven groove 53 is larger than L1 and L2. Therefore, the key 40 is movable relative to the shaft 20 and the external tooth gear 50 in the axial direction of the shaft 20 between the wall surface 534 and the wall surface 535.

<4> The present embodiment includes a movement control unit 82. The movement restricting portion 82 is formed on the wall surface 535 of the driven groove 53 of the external tooth gear 50. The movement restricting unit 82 can regulate the movement of the key 40 toward the plate 72 in the axial direction of the shaft 20 by abutting on the key 40.

In the present embodiment, the movement of the key 40 in the axial direction of the shaft 20 can be regulated by the movement restricting unit 80 and the movement restricting unit 82 formed on the external tooth gear 50. Therefore, as in the first embodiment, it is possible to suppress the key 40 from coming into contact with the cover 71 or the plate 72 of the housing 70 that rotates relative to the key 40, and to suppress the generation of wear debris.

As described above, <4> In the present embodiment, the movement restricting unit 80 and the movement restricting unit 82 are formed on the external tooth gear 50.

Therefore, the movement restricting unit 80 and the movement restricting unit 82 formed on the external tooth gear 50 that rotates synchronously with the key 40 come into contact with the key 40 to restrict the movement of the key 40, so that the housing 70 that rotates relative to the key 40 Compared with the case where the key 40 is contacted to restrict the movement of the key 40 (comparative form), the wear of the key 40 and the like can be suppressed.

(Fifth Embodiment)
A part of the fuel supply pump of the fifth embodiment is shown in FIG. The fifth embodiment is different from the first embodiment in the configuration of the drive groove 23 of the shaft 20, the key 40, and the like.

In the present embodiment, the drive groove 23 is formed in a hole shape that is recessed inward in the radial direction from the outer peripheral wall of the shaft body 21 at a position separated from the end surface of one end of the shaft body 21 in the axial direction by a predetermined distance. In the present embodiment, five wall surfaces of the shaft 20 forming the drive groove 23 are formed in a plane shape.

Here, for convenience, the five planar wall surfaces of the shaft 20 forming the drive groove 23 are referred to as a wall surface 231 and a wall surface 232, a wall surface 233, a wall surface 234, and a wall surface 235, respectively.

The wall surface 231 is a rectangular wall surface formed at a position separated from the outer peripheral wall of the shaft 20 by a predetermined distance and parallel to the axis Ax1 of the shaft 20. The wall surface 232 is a rectangular wall surface that is formed so as to connect the outer peripheral wall of the shaft 20 and the wall surface 231 and is parallel to the axis Ax1 of the shaft 20 and perpendicular to the wall surface 231. The wall surface 233 (not shown) is formed so as to connect the outer peripheral wall of the shaft 20 and the wall surface 231 and is a rectangular wall surface parallel to the axis Ax1 and the wall surface 232 of the shaft 20 and perpendicular to the wall surface 231. Is. The wall surface 234 is formed so as to connect the outer peripheral wall of the shaft 20 and the wall surface 231 and is a substantially rectangular wall surface perpendicular to the shaft Ax1, the wall surface 231 and the wall surface 232 and the wall surface 233 of the shaft 20. The wall surface 235 is formed so as to connect the outer peripheral wall of the shaft 20 and the wall surface 231 and has a substantially rectangular shape perpendicular to the axis Ax1, the wall surface 231 and the wall surface 232 and the wall surface 233 of the shaft 20 and parallel to the wall surface 234. The wall of.

In the present embodiment, the key 40 has a key body 41, a protruding portion 42, and a protruding portion 43.

Like the key 40 of the first embodiment, the key main body 41 is formed in a rectangular columnar shape, and the cross section of the shaft 20 including all the axes Ax1 has an I-shaped cross section.

The projecting portion 42 is integrally formed with the key body 41 so as to project in a rectangular columnar shape from the other end (diametrically outer end) of the key body 41 in the radial direction of the shaft 20 toward the cover bottom portion 712. The projecting portion 43 is integrally formed with the key body 41 so as to project from the other end of the key body 41 in the radial direction of the shaft 20 toward the plate 72 in a rectangular columnar shape. As a result, the key 40 has a T-shaped cross section formed by a virtual plane including all the axes Ax1 of the shaft 20.

<6> In the present embodiment, the axial length L1 of the shaft 20 at one end (diametrically inner end) of the key 40 in the radial direction of the shaft 20 is the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of the shaft 20 (at the outer end in the radial direction). L2 is larger than L1.

The distance between the wall surface 234 and the wall surface 235 of the drive groove 23 is larger than L1 and smaller than L2. The distance between the outer peripheral wall of the shaft 20 and the wall surface 231, that is, the depth of the drive groove 23 is the radial length L3 of the shaft 20 of the key 40 and the radial length of the shaft 20 of the protrusion 42 or the protrusion 43. It is smaller than the length obtained by subtracting the length L4.

In the key 40, the portion of the key body 41 is movable relative to the shaft 20 and the external gear 50 in the axial direction of the shaft 20 between the wall surface 234 and the wall surface 235.

This embodiment includes a movement control unit 83. The movement restricting portion 83 is formed on the wall surface 235 of the drive groove 23 of the shaft 20. The movement restricting unit 83 can restrict the movement of the key 40 toward the cover bottom portion 712 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting portion 83 abuts on the key 40 to restrict the movement of the key 40, the protruding portion 42 of the key 40 does not abut on the wall surface 534 of the driven groove 53.

The movement restricting unit 81 can regulate the movement of the key 40 toward the plate 72 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting portion 81 abuts on the key 40 to restrict the movement of the key 40, the protruding portion 43 of the key 40 does not abut on the surface of the plate 72 on the cover bottom 712 side.

This embodiment does not include the movement control unit 80 shown in the first embodiment.

In this embodiment, L2 is larger than L1. Therefore, the area of the contact surface between the key 40 and the wall surface 532 or the wall surface 533 of the driven groove 53 can be made larger than the area of the contact surface between the key 40 and the wall surface 232 or the wall surface 233 of the drive groove 23. As a result, the surface pressure acting on the key 40 and the external tooth gear 50 can be reduced, and wear of these members can be suppressed.

As described above, <6> In the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of.

When L2 is made larger than L1 as in the present embodiment, the area of the contact surface between the key 40 and the external tooth gear 50 can be increased, the surface pressure can be reduced, and wear can be suppressed.

(Sixth Embodiment)
A part of the fuel supply pump of the sixth embodiment is shown in FIG. The sixth embodiment is different from the fourth embodiment in the configuration of the key 40 and the like.

In the present embodiment, the key 40 has a key body 41, a protruding portion 42, and a protruding portion 43.

Like the key 40 of the fourth embodiment, the key body 41 is formed in a rectangular columnar shape, and the cross section of the shaft 20 including all the axes Ax1 is I-shaped.

The projecting portion 42 is integrally formed with the key body 41 so as to project from one end (diametrically inner end) of the key body 41 in the radial direction of the shaft 20 toward the cover bottom portion 712 in a rectangular columnar shape. The projecting portion 43 is integrally formed with the key body 41 so as to project from one end of the key body 41 in the radial direction of the shaft 20 toward the plate 72 in a rectangular columnar shape. As a result, the key 40 has an inverted T-shaped cross section formed by a virtual plane including all the axes Ax1 of the shaft 20.

<6> In the present embodiment, the axial length L1 of the shaft 20 at one end (diametrically inner end) of the key 40 in the radial direction of the shaft 20 is the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of the shaft 20 (at the outer end in the radial direction). L1 is larger than L2.

The distance between the wall surface 534 and the wall surface 535 of the driven groove 53 is larger than L2 and smaller than L1. The distance between the inner peripheral wall of the external gear 50 and the wall surface 531, that is, the depth of the driven groove 53 is from the radial length L3 of the shaft 20 of the key 40 to the shaft 20 of the protrusion 42 or the protrusion 43. It is smaller than the length obtained by subtracting the radial length L4.

The key 40 is capable of the portion of the key body 41 being relatively movable in the axial direction of the shaft 20 with respect to the shaft 20 and the external gear 50 between the wall surface 534 and the wall surface 535.

The movement restricting unit 80 can restrict the movement of the key 40 toward the cover bottom portion 712 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting portion 80 abuts on the key 40 to restrict the movement of the key 40, the protruding portion 42 of the key 40 does not abut on the surface of the cover bottom portion 712 on the plate 72 side.

The movement restricting unit 82 can regulate the movement of the key 40 toward the plate 72 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting portion 82 abuts on the key 40 to restrict the movement of the key 40, the protruding portion 43 of the key 40 does not abut on the wall surface 234 of the drive groove 23.

In this embodiment, L1 is larger than L2. Therefore, the area of the contact surface between the key 40 and the wall surface 232 or the wall surface 233 of the drive groove 23 can be made larger than the area of the contact surface between the key 40 and the wall surface 532 or the wall surface 533 of the driven groove 53. Thereby, the surface pressure acting on the key 40 and the shaft 20 can be reduced, and the wear of these members can be suppressed.

As described above, <6> In the present embodiment, the axial length L1 of the shaft 20 at one end of the key 40 in the radial direction of the shaft 20 is the shaft 20 at the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of.

When L1 is made larger than L2 as in the present embodiment, the area of the contact surface between the key 40 and the shaft 20 can be increased, the surface pressure can be reduced, and wear can be suppressed.

(7th Embodiment)
A part of the fuel supply pump of the seventh embodiment is shown in FIG. In the seventh embodiment, the configuration of the key 40 and the like are different from those in the sixth embodiment.

In this embodiment, the key 40 does not have the protrusion 43 shown in the sixth embodiment. Therefore, the key 40 has an L-shaped cross section formed by a virtual plane including all the axes Ax1 of the shaft 20.

<6> In the present embodiment, the axial length L1 of the shaft 20 at one end (diametrically inner end) of the key 40 in the radial direction of the shaft 20 is the other end of the key 40 in the radial direction of the shaft 20. It is different from the axial length L2 of the shaft 20 (at the outer end in the radial direction). L1 is larger than L2.

The distance between the wall surface 534 and the wall surface 535 of the driven groove 53 is larger than L2 and smaller than L1. The distance between the inner peripheral wall of the external gear 50 and the wall surface 531, that is, the depth of the driven groove 53 is the radial length of the shaft 20 of the protrusion 42 from the radial length L3 of the shaft 20 of the key 40. It is smaller than the length obtained by subtracting L4.

The movement restricting unit 80 can restrict the movement of the key 40 toward the cover bottom portion 712 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting portion 80 abuts on the key 40 to restrict the movement of the key 40, the protruding portion 42 of the key 40 does not abut on the surface of the cover bottom portion 712 on the plate 72 side.

The movement restricting unit 82 can regulate the movement of the key 40 toward the plate 72 in the axial direction of the shaft 20 by abutting on the key 40. When the movement restricting unit 82 abuts on the key 40 to restrict the movement of the key 40, the key body 41 of the key 40 does not abut on the wall surface 234 of the drive groove 23.

In this embodiment, L1 is larger than L2. Therefore, the area of the contact surface between the key 40 and the wall surface 232 or the wall surface 233 of the drive groove 23 can be made larger than the area of the contact surface between the key 40 and the wall surface 532 or the wall surface 533 of the driven groove 53. Thereby, the surface pressure acting on the key 40 and the shaft 20 can be reduced, and the wear of these members can be suppressed.

(Other embodiments)
In the above embodiment, the low pressure pump 30 has a space 500 between the external teeth 52 and the internal teeth 62 due to the rotation of the external tooth gear 50 as the “rotating member” and the internal tooth gear 60 as the “other member”. An inscribed gear pump that changes volume and sucks and discharges fuel. On the other hand, in another embodiment, the low pressure pump has a first external tooth gear due to the rotation of the first external tooth gear as the "rotating member" and the second external tooth gear as the "other member". It may be an external gear pump in which the volume of the space between the external teeth and the external teeth of the second external gear changes to suck and discharge fuel.

The present invention is not limited to diesel engines, but can also be used to supply fuel to gasoline engines. Further, the present invention is not limited to the fuel supply pump mounted on the vehicle, but can be applied to the fuel supply pump of other vehicles and the like.

As described above, the present disclosure is not limited to the above embodiment, and can be implemented in various forms without departing from the gist thereof.

1 Fuel supply pump, 10 high pressure pump, 20 shaft, 23 drive groove, 30 low pressure pump, 40 key, 50 external tooth gear (rotating member), 53 driven groove, 60 internal tooth gear (other member), 70 housing, 80 , 81, 82, 83 Movement Control Department, 500 Space

Claims (7)

A high-pressure pump (10) that pressurizes fuel and discharges it to the outside,
A low-pressure pump (30) that supplies fuel to the high-pressure pump,
A shaft (20) having a drive groove (23) recessed radially inward from the outer peripheral wall at one end in the axial direction and capable of pressurizing fuel in the high-pressure pump by rotating is provided.
The low pressure pump
A key (40) provided in the drive groove so as to be movable relative to the shaft, and
It is formed in an annular shape so that one end of the shaft is located inside, has a driven groove (53) recessed radially outward from the inner peripheral wall into which the key is fitted, and rotates integrally with the shaft via the key. A rotating member (50) that sucks fuel and supplies it to the high-pressure pump by changing the volume of the space (500) between the other member (60) and the other member (60).
A housing (70) for accommodating the rotating member so as to be relatively rotatable,
A movement restricting unit (80, 81, 82, 83) formed on at least one of the rotating member or the shaft and capable of restricting the movement of the key in the axial direction of the shaft.
A fuel supply pump equipped with. The housing has a cover (71) having an accommodation space (700) for accommodating the rotating member, and a plate (17) forming the accommodation space between the housing and the cover by closing the opening (710) of the cover. 72) The fuel supply pump according to claim 1. The rotating member has external teeth (52) on the outer edge portion and has external teeth (52).
The other member has an internal tooth (62) capable of meshing with the external tooth at the inner edge portion.
The low pressure pump is the internal gear pump according to claim 1 or 2, wherein the volume of the space between the external teeth and the internal teeth changes due to the rotation of the rotating member, and fuel is sucked in and discharged. Fuel supply pump. The fuel supply pump according to any one of claims 1 to 3, wherein the movement control unit (80, 82) is formed on the rotating member. The fuel supply pump according to any one of claims 1 to 3, wherein the movement control unit (80, 81) is formed on the rotating member and the shaft. The axial length (L1) of the shaft at one end of the key in the radial direction of the shaft is different from the axial length (L2) of the shaft at the other end of the key in the radial direction of the shaft. Item 5. The fuel supply pump according to any one of Items 1 to 5. The axial length (L1) of the shaft at one end of the key in the radial direction of the shaft is the same as the axial length (L2) of the shaft at the other end of the key in the radial direction of the shaft. The fuel supply pump according to any one of claims 1 to 5.

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