JP2011220194A - High-pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure pump capable of suppressing wobbling of a sliding shaft induced in a large diameter portion of a plunger.SOLUTION: The plunger 71 has a large diameter portion 711 and a small diameter portion 712. The plunger 71 has a reduced diameter portion 713 that connects the large diameter portion 711 and the small diameter portion 712. In the reduced diameter portion 713, the outer diameter gradually decreases toward the large diameter portion 711, and is the smallest at a connecting portion (indicated by a symbol C) between the reduced diameter portion 713 and the large diameter portion 711. An annular recessed portion 715 opening to a level difference face 714 of the large diameter portion 711 is formed continuously in the circumference direction around the connecting portion.

Description

  The present invention relates to a high-pressure pump used in an internal combustion engine (hereinafter referred to as “engine”).

  A high-pressure pump used for an engine includes a plunger that reciprocates by rotation of a camshaft. The operation of the high-pressure pump is specifically the intake stroke in which fuel is sucked from the fuel gallery in the pump into the pressurizing chamber when the plunger moves from top dead center to bottom dead center, and the plunger moves from bottom dead center to top dead center. The metering process of returning a part of the low-pressure fuel from the pressurization chamber to the fuel gallery, and the pressurization chamber fuel being pressurized by the plunger toward the top dead center after closing the intake valve It is roughly divided into pressure strokes.

  Such a plunger usually has a large-diameter portion that slides inside a cylinder formed inside the housing to create a volume change of the pressurizing chamber, and an outer diameter that is smaller than the large-diameter portion. (See, for example, Patent Literatures 1 and 2).

Special table 2008-525713 JP 2008-101617 A

  By the way, the rotational motion of the camshaft is transmitted to the small diameter portion via a tappet or the like. Thereby, the rotational motion is converted into a linear motion. At this time, not only a load in the axial direction of the small diameter portion but also a load perpendicular to the axial direction (hereinafter referred to as “lateral force”) acts. Therefore, a lateral force is also applied to the large diameter portion connected to the small diameter portion, and the large diameter portion is pressed against the inner wall of the cylinder. As a result, the oil film is cut between the cylinder and the large-diameter portion, and there is a possibility that seizure occurs.

  The present invention has been made to solve the above-described problems, and its purpose is to allow bending of the small-diameter portion and the large-diameter portion and to suppress the shake of the sliding shaft that occurs in the large-diameter portion. The object is to provide a possible high-pressure pump.

  A high-pressure pump made to achieve the above-described object discharges fuel pressurized in a pressurizing chamber, and includes a housing that forms an outer shell, a cylinder that is formed inside the housing, and a large diameter And a plunger having a small diameter portion and the like.

  The large diameter portion of the plunger is slidably supported by the cylinder and creates a change in volume of the pressurizing chamber. The small diameter portion has a smaller outer diameter than the large diameter portion, and transmits the rotational motion of the camshaft as a reciprocating motion corresponding to the cam profile.

Here, in particular, the plunger further has a reduced diameter portion and an annular recess.
The reduced diameter portion of the plunger connects the small diameter portion and the large diameter portion, and the connecting portion with the large diameter portion has an outer diameter smaller than that of the small diameter portion. The annular recess opens to a step surface that is an end surface of the large diameter portion on the reduced diameter portion side, and is formed around the connection portion between the reduced diameter portion and the large diameter portion.

  Conventionally, when a lateral force is applied to the small diameter portion from the camshaft side, a lateral force is also applied to the large diameter portion connected to the small diameter portion, and the large diameter portion is pressed against the inner wall of the cylinder. Therefore, in the present invention, the outer diameter of the connection portion with the large diameter portion is made smaller than that of the small diameter portion, and an annular recess is provided around the connection portion. That is, a slight deformation at the connecting portion is allowed by reducing the outer diameter of the connecting portion and providing the recess.

  In this way, even if a lateral force acts on the small diameter portion, the connecting portion between the reduced diameter portion and the large diameter portion is slightly deformed, so that the lateral force applied to the large diameter portion can be reduced. As a result, it is possible to suppress the shake of the sliding shaft that occurs in the large diameter portion.

  Note that, as shown in claim 2, it is conceivable that the reduced-diameter portion has a configuration in which the outer diameter becomes smaller from the small-diameter portion toward the large-diameter portion. Employing such a reduced diameter portion is advantageous in that it can be processed relatively easily.

  By the way, the annular recess may be discontinuous in the circumferential direction. For example, a plurality of arc-shaped concave portions are formed at intervals in some places, and the whole is formed into an annular shape. However, stress concentration may occur in the discontinuous portion.

  Therefore, as shown in claim 3, the annular recess may be provided continuously in the circumferential direction. If it does in this way, it can control that stress concentration arises by deformation of a connecting portion.

  From the viewpoint of suppressing stress concentration, as shown in claim 4, the shape in a cross section parallel to the axial direction is a smooth curved shape capable of suppressing stress concentration generated in the connecting portion between the reduced diameter portion and the large diameter portion. It is conceivable to form an annular recess so that In this way, it is possible to further suppress the occurrence of stress concentration due to the deformation of the connection portion.

  As described above, the seizure of the plunger is due to the lateral force applied to the large diameter portion. As another factor, the tip side of the large diameter portion becomes high temperature due to the compression of the fuel. It is mentioned that a part becomes high temperature.

  Therefore, as shown in claim 5, on the premise that a variable volume chamber is formed around the small diameter portion and the reduced diameter portion and is filled with fuel, and the volume of the pressurization chamber is changed. However, it is exemplified that the cylindrical space is formed by extending from the connecting portion to the large diameter side. In this way, the sliding of the sliding shaft generated in the large-diameter portion is suppressed, and the large-diameter portion is cooled by filling the cylindrical space with fuel.

  As described above, in the configuration in which the annular recess forms the cylindrical space, as shown in claim 6, the inner member connected to the reduced diameter portion, and the annular recess is joined to the inner member on the distal end side. It can be considered that the large-diameter portion is formed by an outer member formed between the two. This is advantageous in that the cost is reduced as compared with the case where the annular recess is formed by performing processing such as cutting.

It is sectional drawing which shows the structure of the high pressure pump of one Embodiment. It is a side view which shows the plunger of one Embodiment. It is the III-III sectional view taken on the line of FIG. It is a side view which shows the plunger of another embodiment. It is the VV sectional view taken on the line of FIG. It is sectional drawing which shows the modification corresponding to FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The high-pressure pump according to the present embodiment is used by being mounted on a vehicle, pressurizes the fuel pumped up from the fuel tank by the low-pressure pump and supplied from the inlet, and supplies it to the fuel rail to which the injector is connected. A pipe from a low pressure pump is connected to the upstream side of the inlet.

  As shown in FIG. 1, the high-pressure pump 1 includes a main body unit 10, a fuel supply unit 30, a suction valve unit 50, a plunger unit 70, and a discharge valve unit 90.

The main body 10 has a housing 11 that forms an outer shell. A fuel supply unit 30 is formed in a part of the housing 11 (upper part in FIG. 1).
Moreover, the plunger part 70 is provided in the exact opposite side (lower part in FIG. 1) of the fuel supply part 30. FIG. A pressurizing chamber 12 capable of pressurizing fuel is formed near the middle between the plunger unit 70 and the fuel supply unit 30.
Furthermore, an intake valve portion 50 (left side portion in FIG. 1) and a discharge valve portion 90 (right side portion in FIG. 1) are provided in a direction orthogonal to the arrangement direction of the fuel supply portion 30 and the plunger portion 70. .

  Next, the configuration of the fuel supply unit 30, the intake valve unit 50, the plunger unit 70, and the discharge valve unit 90 will be described in detail.

  The fuel supply unit 30 includes a fuel gallery 31. The fuel gallery 31 is a space surrounded by the concave portion 13 and the lid portion 14 of the housing 11. A damper unit 32 is disposed in the fuel gallery 31. The damper unit 32 includes a damper member 35 formed by joining two metal diaphragms 33, 34, a bottom side support portion 36 disposed on the bottom portion 15 of the recess 13, and a lid disposed on the lid portion 14 side. It is comprised with the side support part 37. FIG.

  The fuel gallery 31 has a recess 151 at the bottom 15 that matches the bottom support 36. Thereby, the bottom side support part 36 is positioned by this hollow 151. Further, as shown in FIG. 2, an inlet opening 19 is formed in the recess 151. As a result, the fuel from the low pressure pump is supplied to the radially inner region of the bottom support 36.

  A wave spring 38 is disposed above the lid side support portion 37. Thus, in a state where the lid portion 14 is attached to the housing 11, the wave spring 38 presses the lid side support portion 37 toward the bottom portion 15 side. As a result, the damper member 35 is sandwiched by the lid-side support portion 37 and the bottom-side support portion 36 with a uniform force in the circumferential direction.

Next, the plunger part 70 will be described.
As shown in FIG. 1, the plunger unit 70 includes a plunger 71, an oil seal holder 72, a spring seat 73, a plunger spring 74, and the like.

  The plunger 71 has a large-diameter portion 711 supported by a cylinder 16 formed inside the housing 11 and a small-diameter portion 712 having a smaller outer diameter than the large-diameter portion 711. The small diameter portion 712 is surrounded by the oil seal holder 72. The large diameter portion 711 and the small diameter portion 712 are integrated and reciprocate in the axial direction.

  The oil seal holder 72 is disposed at the end of the cylinder 16 and has a base 721 located on the outer periphery of the small diameter portion 712 of the plunger 71 and a press-fit portion 722 that is press-fitted into the housing 11.

  The base 721 has a ring-shaped seal 723 inside. The seal 723 includes an inner peripheral Teflon ring (“Teflon” is a registered trademark) and an outer peripheral O-ring. By this seal 723, the thickness of the fuel oil film around the small diameter portion 712 of the plunger 71 is adjusted, and fuel leakage to the engine is suppressed.

  In addition, the base 721 has an oil seal 725 at the tip. The oil seal 725 regulates the thickness of the oil film around the small diameter portion 712 of the plunger 71, thereby suppressing oil leakage.

  The press-fitting portion 722 is a portion that protrudes in a cylindrical shape around the base portion 721, and the cylindrical portion has a U-shaped longitudinal section. On the other hand, a recess 17 corresponding to the press-fit portion 722 is formed in the housing 11. As a result, the oil seal holder 72 is press-fitted in such a manner that the press-fitting portion 722 is pressed against the radially inner wall of the recess 17.

  The spring seat 73 is disposed at the end of the plunger 71. The end of the plunger 71 is in contact with a tappet (not shown). The tappet makes its outer surface contact a cam attached to a camshaft (not shown), and reciprocates in the axial direction according to the cam profile by the rotation of the camshaft. As a result, the plunger 71 reciprocates in the axial direction.

  One end of the plunger spring 74 is locked to the spring seat 73, and the other end is locked to the deep portion of the press-fit portion 722 of the oil seal holder 72. Thereby, the plunger spring 74 functions as a return spring of the plunger 71 and urges the plunger 71 to contact the tappet.

  With this configuration, the reciprocating movement of the plunger 71 according to the rotation of the camshaft is realized. At this time, a volume change of the pressurizing chamber 12 is created by the large diameter portion 711 of the plunger 71.

  In this embodiment, in particular, a variable volume chamber 75 is formed around the small diameter portion 712 of the plunger 71. Here, a region surrounded by the cylinder 16 of the housing 11 and the base end surface (step surface with the small diameter portion 712) of the large diameter portion 711 of the plunger 71, the outer peripheral wall of the small diameter portion 712, and the seal 723 of the oil seal holder 72. Is the variable volume chamber 75. Although the seal 723 suppresses fuel leakage as described above, the seal 723 seals the variable volume chamber 75 in a liquid-tight manner and prevents fuel leak from the variable volume chamber 75 to the engine.

  The variable volume chamber 75 includes a cylindrical cylindrical passage 727 formed between the press-fit portion 722 and the concave portion 17 in the radially inward direction, an annular annular passage 728 formed deep in the concave portion 17, and the housing 11. It is connected to the bottom 15 of the fuel gallery 31 via the formed volume-side passage 18 (passage indicated by a broken line in the figure).

Next, the suction valve unit 50 will be described.
As shown in FIG. 1, the suction valve unit 50 includes a cylinder part 51 formed by the housing 11, a valve part cover 52 that covers the opening of the cylinder part 51, a connector 53, and the like.
The cylindrical portion 51 is formed in a substantially cylindrical shape, and the inside is a fuel passage 55. A substantially cylindrical seat body 56 is disposed in the fuel passage 55. A suction valve 57 is disposed inside the seat body 56. Further, the fuel passage 55 communicates with the fuel gallery 31 via the pressure side passage 58.

  A needle 59 is in contact with the suction valve 57. The needle 59 passes through the valve cover 52 described above and extends to the inside of the connector 53. The connector 53 includes a coil 531 and a terminal 532 for energizing the coil 531. Inside the coil 531, a fixed core 533, a movable core 534, and a spring 535 interposed between the fixed core 533 and the movable core 534 are disposed. Here, the needle 59 described above is fixed to the movable core 534. That is, the movable core 534 and the needle 59 are integrated.

  With this configuration, when energization is performed via the terminal 532 of the connector 53, a magnetic attractive force is generated between the fixed core 533 and the movable core 534 by the magnetic flux generated in the coil 531. As a result, the movable core 534 moves to the fixed core 533 side, and accordingly, the needle 59 moves in a direction away from the pressurizing chamber 12. At this time, the movement of the suction valve 57 is not restricted by the needle 59. Therefore, the suction valve 57 can be seated on the seat body 56, and the fuel passage 55 and the pressurizing chamber 12 are blocked by the seating of the suction valve 57.

  On the other hand, if energization through the terminal 532 of the connector 53 is not performed, no magnetic attractive force is generated, so that the movable core 534 is moved toward the pressurizing chamber 12 by the spring 535. As a result, the needle 59 moves in a direction approaching the pressurizing chamber 12. As a result, the movement of the suction valve 57 is regulated by the needle 59, and the suction valve 57 is held on the pressurizing chamber 12 side. At this time, the intake valve 57 is separated from the seat body 56, and the fuel passage 55 and the pressurizing chamber 12 communicate with each other.

Next, the discharge valve unit 90 will be described.
As shown in FIG. 1, the discharge valve portion 90 has a cylindrical accommodating portion 91 formed by the housing 11. A discharge valve 92, a spring 93, and a locking portion 94 are accommodated in a storage chamber 911 formed by the storage portion 91. Further, the opening portion of the storage chamber 911 is a discharge port 95. A valve seat is formed in the deep portion of the storage chamber 911 opposite to the discharge port 95.

  The discharge valve 92 contacts the valve seat by the biasing force of the spring 93 and the pressure from the fuel rail (not shown). As a result, the discharge valve 92 stops discharging fuel while the fuel pressure in the pressurizing chamber 12 is low. On the other hand, when the pressure of the fuel in the pressurizing chamber 12 increases and overcomes the biasing force of the spring 93 and the pressure from the fuel rail side, the discharge valve 92 moves toward the discharge port 95. As a result, the fuel that has flowed into the storage chamber 911 is discharged from the discharge port 95.

Here, the present embodiment is particularly characterized in the structure of the plunger 71 of the plunger portion 70. 2 is a side view of the plunger 71, and FIG. 3 is a cross-sectional view taken along line III-III in FIG.
As described above, the plunger 71 has the large diameter portion 711 and the small diameter portion 712. Furthermore, the plunger 71 includes a reduced diameter portion 713 that connects the large diameter portion 711 and the small diameter portion 712. The reduced diameter portion 713 has an outer diameter that decreases toward the large diameter portion 711. And as shown in FIG. 3, the outer diameter of the connection part (it showed with the symbol C) of the reduced diameter part 713 and the large diameter part 711 is the smallest.

  An annular recess 715 that opens to the stepped surface 714 of the large diameter portion 711 is formed around the connection portion. Here, the step surface 714 is an end surface of the large diameter portion 711 on the reduced diameter portion 713 side. The annular recess 715 is provided continuously in the circumferential direction. Moreover, as shown in FIG. 3, when the cross section is viewed, it has a smooth curved shape capable of suppressing stress concentration occurring in the connection portion. Specifically, it is an arcuate recess that smoothly connects to the outer wall of the reduced diameter portion 713.

  Conventionally, when a lateral force acts on the small diameter portion 712 from the camshaft side, a lateral force is also applied to the large diameter portion 711 connected to the small diameter portion 712, and the large diameter portion 711 is pressed against the inner wall of the cylinder 16 (see FIG. 1). The situation that is done occurs. As a result, seizure of the large diameter portion 711 becomes a problem.

  Therefore, in this embodiment, as shown in FIG. 3, by providing the reduced diameter portion 713, the outer diameter of the connection portion between the reduced diameter portion 713 and the large diameter portion 711 is made smaller than that of the small diameter portion 712, and An annular recess 715 was provided around the periphery. That is, a slight deformation at the connecting portion is allowed.

  In this way, even if a lateral force acts on the small diameter portion 712, the connecting portion between the reduced diameter portion 713 and the large diameter portion 711 is slightly deformed, thereby reducing the lateral force applied to the large diameter portion 711. be able to. As a result, the shake of the sliding shaft that occurs in the large-diameter portion 711 can be suppressed, and consequently the seizure of the large-diameter portion 711 can be prevented.

  Further, the outer diameter of the reduced diameter portion 713 decreases as it goes from the small diameter portion 712 to the large diameter portion 711. Thereby, formation of the reduced diameter part 713 becomes easy. Furthermore, since the annular recess 714 is continuously provided in the circumferential direction, it is possible to suppress stress concentration due to deformation of the connection portion.

  From the viewpoint of suppressing the stress concentration, in this embodiment, the cross-sectional shape of the annular recess 714 shown in FIG. 3 is a smooth curved shape capable of suppressing the stress concentration generated in the connection portion, that is, the reduced diameter portion 713. It has an arc shape that smoothly connects to the outer wall. Thereby, it can suppress further that stress concentration arises by the deformation | transformation of a connection part.

  In this embodiment, the pressurizing chamber 12 constitutes the “pressurizing chamber” described in the claims, the housing 11 constitutes the “housing”, the cylinder 16 constitutes the “cylinder”, and the plunger 71. Constitutes a “plunger”, a large diameter portion 711 constitutes a “large diameter portion”, a small diameter portion 712 constitutes a “small diameter portion”, a reduced diameter portion 713 constitutes a “reduced diameter portion”, and a step surface 714 constitutes a “step surface”, and the annular recess 715 constitutes an “annular recess”.

  As mentioned above, this invention is not limited to the said form at all, In the range which does not deviate from the meaning, it can implement with a various form.

(A) For example, it is conceivable to employ a plunger 800 as shown in FIG. 4 is a side view of the plunger 800, and FIG. 5 is a cross-sectional view taken along the line VV of FIG.
As shown in FIG. 4, the plunger 800 has a large-diameter portion 801, a small-diameter portion 802, and a reduced-diameter portion 803 as in the above embodiment. As shown in FIG. 5, the reduced diameter portion 803 has an outer diameter that decreases toward the large diameter portion 801, and a connection portion (indicated by symbol D) between the reduced diameter portion 803 and the large diameter portion 801. ) Has the smallest outer diameter.

  Around this connection portion, an annular recess 805 that opens to the step surface 804 of the large-diameter portion 801 is formed. Here, the step surface 804 is an end surface of the large diameter portion 801 on the reduced diameter portion 803 side. The annular recess 805 is provided continuously in the circumferential direction. Further, as shown in FIG. 5, the annular recess 805 extends to the large diameter portion 801 side to form a cylindrical space 806. In this case, the cylindrical space 806 is connected to the variable volume chamber 75 (see FIG. 1).

  As a result, the same effects as in the above embodiment can be obtained. In addition, the large-diameter portion 801 is cooled by filling the cylindrical space 806 with fuel. As a result, seizure of the large diameter portion 801 can be prevented.

  At this time, the plunger 800 constitutes the “plunger” of “Claims”, the large-diameter portion 801 constitutes the “large-diameter portion”, and the small-diameter portion 802 constitutes the “small-diameter portion”. The portion 803 forms a “reduced diameter portion”, the step surface 804 forms a “step surface”, the annular recess 805 forms an “annular recess”, and the cylindrical space 806 forms a “cylindrical space”.

(B) Instead of the plunger 800, it is conceivable to employ a plunger 810 as shown in FIG.
As shown in FIG. 6, the plunger 810 has a large-diameter portion 811, a small-diameter portion 812, and a reduced-diameter portion 813, as in the above embodiment. The outer diameter of the reduced diameter portion 813 decreases as it goes toward the large diameter portion 811, and the outer diameter of the connection portion (indicated by symbol E) between the reduced diameter portion 813 and the large diameter portion 811 is the most. It is getting smaller.

  An annular recess 815 that opens to the stepped surface 814 of the large-diameter portion 811 is formed around the connection portion. Here, the step surface 814 is an end surface of the large diameter portion 811 on the reduced diameter portion 813 side. The annular recess 815 is continuously provided in the circumferential direction. As shown in FIG. 6, the annular recess 815 extends toward the large diameter portion 811 to form a cylindrical space 816. In this case, the cylindrical space 816 is connected to the variable volume chamber 75 (see FIG. 1).

  Here, in particular, the large-diameter portion 811 includes an inner member 817 connected to the reduced-diameter portion 813 and an outer member 818 joined to the inner member 817 on the distal end side. The outer member 818 forms the annular recess 815 with the inner member 817. The inner member 817 and the outer member 818 are joined by press fitting, welding, or the like.

  As a result, the same effect as the plunger 800 can be obtained. In addition, it is advantageous in that the cost is reduced as compared with the case where the annular recess 815 is formed by performing processing such as cutting.

  Here, the plunger 810 constitutes the “plunger” of “Claims”, the large-diameter portion 811 constitutes the “large-diameter portion”, and the small-diameter portion 812 constitutes the “small-diameter portion”. The portion 813 constitutes a “reduced diameter portion”, the step surface 814 constitutes a “step surface”, the annular recess 815 constitutes an “annular recess”, the cylindrical space 816 constitutes a “cylindrical space”, and the inner member 817 constitutes an “inner member”, and the outer member 818 constitutes an “outer member”.

  1: high pressure pump, 10: main body, 11: housing, 12: pressurization chamber, 13: recess, 14: lid, 15: bottom, 16: cylinder, 17: recess, 18: volumetric passage, 19: opening 30: Fuel supply part, 31: Fuel gallery, 32: Damper unit, 33, 34: Diaphragm, 35: Damper member, 36: Bottom side support part, 37: Cover side support part, 50: Suction valve part, 51 : Cylinder part, 52: valve part cover, 53: connector, 531: coil, 532: terminal, 533: fixed core, 534: movable core, 535: spring, 55: fuel passage, 56: seat body, 57: intake valve 58: Pressure side passageway, 59: Needle, 70: Plunger part, 71: Plunger, 711: Large diameter part, 712: Small diameter part, 713: Reduced diameter part, 714: Step surface, 714: Annular recess, 714: Step surface, 15: annular recess, 72: oil seal holder, 721: base, 722: press fit, 723: seal, 725: oil seal, 727: cylindrical passage, 728: annular passage, 73: spring seat, 74: plunger spring, 75 : Variable volume chamber, 90: Discharge valve portion, 91: Storage portion, 911: Storage chamber, 92: Discharge valve, 93: Spring, 94: Locking portion, 95: Discharge port, 800, 810: Plunger, 801, 811 : Large diameter portion, 802, 812: small diameter portion, 803, 813: reduced diameter portion, 804, 814: stepped surface, 805, 815: annular recess, 806, 816: cylindrical space, 817: inner member, 818: outer member

Claims (6)

A high-pressure pump that discharges fuel pressurized in a pressurizing chamber;
A housing forming an outer shell;
A cylinder formed inside the housing;
A large-diameter portion that is slidably supported by the cylinder and creates a volume change of the pressurizing chamber, and a small-diameter portion that has a smaller outer diameter than the large-diameter portion and transmits the rotational movement of the camshaft as a reciprocating motion according to the cam profile. A reduced diameter portion connecting the small diameter portion and the large diameter portion, and a connecting portion with the large diameter portion having an outer diameter smaller than the small diameter portion, and an end surface of the large diameter portion on the reduced diameter portion side A plunger having an annular recess that is opened in a stepped surface and is formed around a connection portion between the reduced diameter portion and the large diameter portion;
A high pressure pump characterized by comprising: The high-pressure pump according to claim 1,
The reduced diameter portion has an outer diameter that decreases from the small diameter portion toward the large diameter portion. The high-pressure pump according to claim 1 or 2,
The high-pressure pump, wherein the annular recess is provided continuously in the circumferential direction. In the high pressure pump according to any one of claims 1 to 3,
The annular recess is a high-pressure pump characterized in that the shape in a cross section parallel to the axial direction is a smooth curved shape capable of suppressing stress concentration occurring at the connecting portion between the reduced diameter portion and the large diameter portion. . In the high pressure pump according to any one of claims 1 to 4,
Around the small-diameter portion and the reduced-diameter portion, a variable volume chamber that is filled with fuel and changes in volume with a change in volume of the pressurizing chamber is formed.
The high-pressure pump, wherein the annular recess extends from the connection portion toward the large-diameter portion to form a cylindrical space. The high-pressure pump according to claim 5,
The large-diameter portion is composed of an inner member connected to the reduced-diameter portion, and an outer member that is joined to the inner member on the distal end side to form the annular recess with the inner member. High-pressure pump characterized.

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