High-pressure fuel pump

Patent metadata

Field	Value
Publication number	US-9759173-B2
Application number	US-201514704057-A
Country	US
Kind code	B2
Filing date	May 5, 2015
Priority date	Oct 6, 2009
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A high-pressure fuel pump includes a pump body, a plunger, a retainer, a spring that is configured to energize the plunger in a direction opposite to a direction of the pressurizing chamber, and a tappet covering the retainer from a side of an end portion of the retainer and the plunger. The retainer is provided with a projection portion protruding to a side of the tappet. The projection portion is separated from the tappet by a predetermined distance along an axial direction of the plunger.

First claim

The invention claimed is:

1. A high-pressure fuel pump comprising:
a pump body in which a pressurizing chamber is formed;
a plunger that is configured to change a volume of the pressurizing chamber;
a retainer that is fixed to an opposite side of the plunger;
a spring that is configured to energize the plunger in a direction opposite to a direction of the pressurizing chamber; and
a tappet covering the retainer from a side of an end portion of the retainer and the plunger, wherein
the retainer is provided with a projection portion protruding to a side of the tappet, and
the projection portion is separated from the tappet by a predetermined distance along an axial direction of the plunger.

2. The high-pressure fuel pump as claimed in claim 1 , wherein the predetermined distance between the projection portion of the retainer and the tappet is smaller than other clearances formed between the retainer and the tappet along the axial direction of the plunger, the other clearances are formed outside the projection portion.

3. The high-pressure fuel pump as claimed in claim 1 , wherein the projection portion of the retainer is inclined toward a bottom part of the tappet from an outer circumference side of the tappet to an inner circumference side.

4. The high-pressure fuel pump as claimed in claim 1 , wherein the projection portion of the retainer is provided with a planar part and an inclined part formed outside of the planar part.

5. The high-pressure fuel pump as claimed in claim 1 , wherein the projection portion of the retainer has a spherical surface in a leading end portion thereof.

6. The high-pressure fuel pump as claimed in claim 1 , wherein a surface hardness of the projection portion of the retainer is smaller than a surface hardness of the plunger.

7. The high-pressure fuel pump as claimed in claim 1 , wherein the retainer and the projection portion are integrally formed by press molding from a sheet member.

8. The high-pressure fuel pump as claimed in claim 1 , wherein a chamfer is applied to an outer peripheral portion of the retainer which is opposed to an inner peripheral surface of the tappet.

9. The high-pressure fuel pump as claimed in claim 1 , wherein an end surface of the plunger protrudes out of a leading end portion of the projection portion to a bottom side of the tappet.

10. The high-pressure fuel pump as claimed in claim 1 , wherein a through hole is formed within the retainer portion, and the plunger is press-fitted with the retainer portion.

11. The high-pressure fuel pump as claimed in claim 1 , wherein the projection portion is closer to the plunger than to the spring.

12. The high-pressure fuel pump as claimed in claim 11 , wherein an end of the retainer portion, on which the projection is defined, is flat except for the projection.

13. A high-pressure fuel pump comprising:
a pump body in which a pressurizing chamber is formed;
a plunger that is configured to change a volume of the pressurizing chamber;
a retainer that is fixed to an opposite side of the plunger;
a spring that is configured to energize the plunger in a direction opposite to a direction of the pressurizing chamber; and
a tappet covering the retainer from a side of an end portion of the retainer and the plunger, wherein
the retainer is provided with a projection portion protruding to a side of the tappet, and
the projection that extends away from the retainer along a longitudinal direction of the high-pressure fuel pump, wherein
a fixing force fixes the retainer relative to the plunger in such a way that when the plunger contacts the tappet, the projection is separated from the tappet by a predetermined distance along an axial direction of the plunger.

14. A high-pressure fuel pump comprising:
a pump body in which a pressurizing chamber is formed;
a plunger that is configured to change a volume of the pressurizing chamber;
a retainer that is fixed to an opposite side of the plunger;
a spring that is configured to energize the plunger in a direction opposite to a direction of the pressurizing chamber; and
a tappet covering the retainer from a side of an end portion of the retainer and the plunger, wherein
the retainer is provided with a projection portion protruding to a side of the tappet,
the projection that extends away from the retainer along a longitudinal direction of the high-pressure fuel pump toward the tappet,
the plunger includes a concave portion in the middle thereof that defines a void when the plunger contacts the tappet,
a fixing force fixes the retainer relative to the plunger in such a way that when the plunger contacts the tappet, the projection is separated from the tappet by a predetermined distance along an axial direction of the plunger; and
the retainer includes an inclined section that extends from a first surface of the retainer that is immediately to the tappet to a second surface of the retainer that is immediately adjacent to the spring, so that the second surface extends radially away from the concave portion farther than the first surface by an amount that is at least three times larger than the predetermined distance.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Hashida Minoru
• Yamada Hiroyuki
• Suganami Masayuki
• Takahashi Sunao
• Onose Toru
• Yamauchi Hideaki
• Ishige Kazuichi

Classifications

• F02M59/102 Primary

  Mechanical drive, e.g. tappets or cams (F02M45/063 takes precedence) · CPC title

• F02M59/025

  characterised by a single piston · CPC title

• F02M59/442

  means preventing fuel leakage around pump plunger, e.g. fluid barriers · CPC title

• F02M59/44

  Details, components parts, or accessories not provided for in, or of interest apart from, the apparatus of groups F02M59/02 - F02M59/42; {Pumps having transducers, e.g. to measure displacement of pump rack or piston} · CPC title

• F04B1/0408

  Pistons · CPC title