JP2009185613A - High-pressure fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost high-pressure fuel pump by eliminating machining of an inside diameter after assembling a cylinder. <P>SOLUTION: The peripheral portion of the end of a cylinder, on the side opposite to a pressurizing chamber, is held by a ring-shaped separate member connected and fixed to a pump body, and the ring-shaped separate member receives pressure contact force of a metal contact seal part between the pump body and the cylinder. Preferably, the peripheral portion of the cylinder is sandwiched between the pump body and the ring-shaped separate member to fix the cylinder to the pump body. Thereby, a pump assembling process can be simplified. Also, choices of cylinder material and surface treatment increase. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a high-pressure fuel pump, and more particularly to a configuration for holding a pressing force for a metal contact seal in a high-pressure fuel pump having a metal contact seal portion with a pump housing on the outer periphery of a cylinder.

  Conventionally, both are fixed by directly caulking the pump body to the outer periphery of the lower end of the cylinder opposite to the pressurizing chamber.

WO2006-069819 International Publication Pamphlet

  In the above prior art, since the cylinder inner diameter is deformed by caulking, the inner diameter is ground after the cylinder is caulked on the pump body. Therefore, it is also necessary to remove burrs, chips and clean up after search processing. In addition, the cylinder may be subjected to heat treatment in order to improve the wear resistance, but there is a concern that cracking due to caulking may occur as the cylinder hardness increases by heat treatment.

  An object of the present invention is to eliminate the inner diameter machining after assembling the cylinder and supply a low-cost high-pressure fuel pump.

  In order to achieve the above-mentioned object, the present invention holds the outer peripheral portion of the cylinder on the side opposite to the pressurizing chamber with a ring-shaped separate member that is joined and fixed to the pump body, and a metal between the pump body and the cylinder. The pressure contact force of the contact seal portion is received by another ring-shaped member. Preferably, the cylinder is fixed to the pump body by sandwiching the outer peripheral portion of the Linda between the pump body and another ring-shaped member.

  Thereby, a pump assembly process can be simplified. In addition, options for cylinder material and surface treatment increase.

  An embodiment of the present invention will be described below with reference to the drawings.

Example 1
FIG. 1 is a longitudinal sectional view showing the entire high-pressure fuel supply pump in which the present invention is implemented.

  A suction joint 10 and a discharge joint 11 are fixed to the pump body 1. The suction joint 10 is fixed to the pump body 1 at a circumferential position (a position indicated by a broken line CP) that does not appear in the entire longitudinal section of FIG.

  The suction joint 10 and the low-pressure chamber that houses the damper 80 are communicated with each other through a part of a low-pressure fuel passage (not shown), and the low-pressure chamber that houses the damper 80 and the suction chamber 10a are in fluid communication. An electromagnetic solenoid valve 200 is attached to the suction chamber 10a.

  The solenoid of the electromagnetic solenoid valve 200 is electromagnetically controlled by a signal from a control unit (not shown), so that the valve body 201 is magnetically operated, whereby the communication between the suction chamber 10a and the pressurizing chamber 12 is cut off. Is controlled.

  In the pressurizing chamber 12, the tip of the plunger 2 that slides into the sliding hole of the cylinder 20 is disposed so as to protrude from the end of the cylinder 20, and this plunger 2 reciprocates following the rotation of the cam 7. To do.

  As a result, the volume of the pressurizing chamber 12 changes following the reciprocation of the plunger, and when the plunger 2 descends downward in the figure in the state of FIG. 1, the volume of the pressurizing chamber 12 increases, Fuel flows into the pressurizing chamber 12 from the valve body 201 of the electromagnetic solenoid valve 200.

  If the valve body 201 of the electromagnetic solenoid valve 200 remains open after the plunger 2 starts to rise, the fuel in the pressurizing chamber 12 overflows into the suction chamber 10a.

  When the valve body 201 of the electromagnetic solenoid valve 200 is closed by a signal from the control unit, the fuel pressure in the pressurizing chamber starts increasing from that point.

  The sum of the force of the spring 6A pressing the discharge valve 6 against the valve seat 6B and the fuel pressure on the non-pressurizing chamber side (inside the high-pressure side passage) acting in the direction of pressing the discharge valve against the valve seat 6B across the discharge valve When the fuel pressure in the pressurizing chamber 12 becomes larger than the applied force, the discharge valve 6 is opened.

  When the discharge valve 6 is opened, the fuel in the pressurizing chamber 12 is discharged to the discharge joint 11.

  As a result, the discharge joint 11 constitutes a check valve that restricts the direction of fuel flow.

  The cylinder 20 has an outer peripheral flange portion 20 </ b> B held between the pump body 1 by a ring (annular member) 8 formed as a separate member.

  The ring 8 is press-fitted, swaged, plastically bonded or welded to the pump body 1, and the cylinder 20 is held by a clamping force between the ring 8 and the pump body 1. By this clamping force, the step portion formed in the pump body 1 and the step portion formed in the cylinder 20 are pressed against each other, and a metal contact seal is achieved by the press contact force.

  Thereby, the cylinder 20 can prevent deformation of the inner diameter, and there is no need to grind the inner diameter after assembling to the pump body.

  The ring 8 can be joined to the pump body 1 by caulking, welding, pressure welding, or the like.

  An embodiment of the joint fixing structure of the pump body 1 and the ring 8 will be described with reference to the left drawing of FIG.

  The tip of the cylinder 20 is inserted into the cylindrical portion of the pump body 1, and the outer peripheral flange portion 20 </ b> B of the cylinder 20 is brought into contact with the annular step portion of the pump body 1.

  Next, the ring 8 is press-fitted into the cylindrical portion of the pump body 1 from the lower end side of the outer peripheral flange portion 20 </ b> B of the cylinder 20. The diameter of the cylindrical portion of the pump body 1 is formed to be larger by the dimension D around the lower end of the outer peripheral flange portion 20 </ b> B of the cylinder 20. The outer diameter of the ring 8 is formed to be larger than the inner diameter of the cylindrical portion of the pump body 1, and the joint surface between the two becomes an inclined surface during press-fitting.

  At this time, the upper surface of the outer peripheral flange portion 20B of the cylinder 20 is pressed against the annular step portion of the pump body, and a metal contact seal is formed on the pressure contact surface portion by the force.

  In this embodiment, thereafter, the end surface of the inner peripheral portion of the pump body 1 surrounding the outer periphery of the ring 8 is pressurized to cause the pump body 1 to plastically flow, thereby constituting a retaining ring.

  The right drawing of FIG. 2 is an enlarged view showing another embodiment of the left drawing. In this embodiment, the ring 8 is press-fitted into the cylindrical portion of the pump body 1 from the lower end side of the outer peripheral flange portion 20B of the cylinder 20, and the upper surface of the outer peripheral flange portion 20B of the cylinder 20 is pressed against the annular step portion of the pump body 1. With the seal formed, the ring 8 and the pump body 1 are welded.

  In the embodiment shown in FIG. 3, the ring 8 is press-fitted into the cylindrical portion of the pump body 1 from the lower end side of the outer peripheral flange portion 20 </ b> B of the cylinder 20, and the upper surface of the outer peripheral flange portion 20 </ b> B of the cylinder 20 is the annular stepped portion of the pump body 1. In a state where a seal is formed by pressure contact with each other, the inner peripheral portion of the pump body 1 is crimped so as to wrap the outer peripheral portion of the ring 8, and the two are fixed.

  In the embodiment shown in FIG. 4, the lower end of the pump body 1 around the ring 8 is pressurized as indicated by the arrow G, and the pump body 1 is plastically flowed into at least one V groove formed on the outer periphery of the ring 8. The tight force acting on both prevents it from coming off.

  In the embodiment shown in FIG. 5, the ring 8 and the pump body 1 are pressurized by pressing the ring 8 toward the cylinder 20 as shown by the arrow SD in a state where current flows between the ring 8 and the pump body 1 and heated. A plastic flow is generated between the joint surfaces of the two, and an inclined surface composed of a new surface from which the surface layer has been removed is formed.

  In any of the above embodiments, external force such as caulking is not directly applied to the cylinder 20, so that the cylinder 20 is not cracked even if it is formed of a hard material.

  The cylinder 20 can be subjected to nitriding treatment with poor weldability in order to improve wear resistance.

The whole longitudinal cross-sectional view of a high pressure fuel supply pump. Enlarged sectional view of the ring joint (laser welding). The expanded sectional view of a ring joined part (caulking). The expanded sectional view of a ring joined part (metal flow). The expanded sectional view of a ring joined part (solid layer joining).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pump body 2 Plunger 3 Lifter 4 Spring 6 Discharge valve 7 Cam 8 Ring 10 Suction joint 10a Suction chamber 11 Discharge joint 12 Pressurization chamber 20 Cylinder 21 Spring holder 40 Damper cover 200 Electromagnetic solenoid valve 201 Valve body

Claims (7)

A pump housing formed with a recess for forming a pressurizing chamber;
A first cylindrical surface portion formed on the inner wall of the recess,
A cylinder having a cylindrical outer peripheral surface portion fitted to the first cylindrical surface portion, a cylinder having a through hole whose one end is open to the pressurizing chamber at the center portion;
A piston plunger that slides in the through hole and repeats reciprocating motion to suck fluid into the pressurizing chamber and pressurize and discharge the fluid from the pressurizing chamber;
The cylinder has a metal contact portion pressed against the pump housing at an outer peripheral portion thereof, and a metal contact seal is achieved by the metal contact portion,
An end of the cylinder opposite to the pressurizing chamber is provided with an annular member that maintains a force for pressing the cylinder against the pump housing and that functions to prevent the cylinder and the pump housing from coming off.
The annular member is a high-pressure fuel supply pump in which a joint fixing region with the pump housing is formed on an outer diameter portion thereof. In claim 1,
The high-pressure fuel supply pump in which the joint fixing region is plastically flowed to the other side when either the annular member or the pump housing is plastically deformed, and both are joined and fixed by the pressing force of the plastic flow portion. A high-pressure fuel supply pump having a coupling and fixing structure in which the pump housing is crimped so that the joining and fixing region wraps around the lower end of the outer periphery of the annular member. In claim 1,
The high-pressure fuel supply pump, wherein the joint fixing region is formed by a weld joint that welds between the annular member and the pump housing. The thing of Claim 4 WHEREIN:
A high-pressure fuel supply pump in which the weld joint is formed by laser welding. The thing of Claim 4 WHEREIN:
A high-pressure fuel supply pump in which the weld joint is solid-layer joined by resistance welding. The thing of Claim 4 WHEREIN:
A high pressure fuel supply pump in which the weld joint is friction welded by friction welding.

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