Fuel Pump

Patent metadata

Field	Value
Publication number	US-2023193865-A1
Application number	US-202117927179-A
Country	US
Kind code	A1
Filing date	May 19, 2021
Priority date	Jul 17, 2020
Publication date	Jun 22, 2023
Grant date	—

Abstract

The present invention provides a fuel pump capable of suppressing sticking of a plunger. The fuel pump of the present invention includes a plunger 2 that reciprocates, a cylinder 6 in which a guide hole 6a that guides the reciprocating motion of the plunger 2 extends in the axial direction, and a pump body 1 that holds the cylinder 6. The pump body 1 includes a cylinder insertion hole 1g into which the cylinder 6 is inserted, and a pressurizing chamber 11 that communicates with the cylinder insertion hole 1g and has a volume increased or decreased by the reciprocating motion of the plunger 2. The cylinder 6 includes a press-fitting portion 6b press-fitted into the inner peripheral surface of the cylinder insertion hole 1g, and a groove 6d formed at a position corresponding to the press-fitting portion 6b on the inner peripheral surface of the guide hole 6a.

First claim

1 . A fuel pump comprising:
a plunger that reciprocates; a cylinder in which a guide hole for guiding a reciprocating motion of the plunger extends in an axial direction; and a pump body that includes a cylinder insertion hole into which the cylinder is inserted, and a pressurizing chamber that communicates with the cylinder insertion hole and has a volume increased or decreased by the reciprocating motion of the plunger, and holds the cylinder, wherein the cylinder includes a press-fitting portion in contact with an inner peripheral surface of the cylinder insertion hole, and a groove formed at a position corresponding to the press-fitting portion on an inner peripheral surface of the guide hole.

2 . The fuel pump according to claim 1 , wherein
a length of the groove in an axial direction of the cylinder is longer than a length of the press-fitting portion in the axial direction of the cylinder.

3 . The fuel pump according to claim 1 , wherein
a central portion of the groove coincides with a central portion of the press-fitting portion in the axial direction of the cylinder.

4 . The fuel pump according to claim 1 , wherein
the press-fitting portion is provided below an intermediate portion in the axial direction of the cylinder.

5 . The fuel pump according to claim 1 , wherein
the press-fitting portion is press-fitted into an inner peripheral surface on an opening side of the cylinder insertion hole.

6 . The fuel pump according to claim 1 , wherein
the cylinder includes a large-diameter portion having an end surface in contact with a contact portion provided inside the pump body, and a small-diameter portion continuously extending to the pressurizing chamber side from the end surface of the large-diameter portion.

7 . The fuel pump according to claim 6 , wherein
the press-fitting portion is formed on an outer peripheral surface of the large-diameter portion.

8 . The fuel pump according to claim 1 , wherein
the cylinder includes an engaging portion provided on a side opposite to the pressurizing chamber with respect to the press-fitting portion, the pump body includes a fixing portion protruding from an inner peripheral surface of the cylinder insertion hole, and the fixing portion presses the engaging portion of the cylinder toward the pressurizing chamber.

9 . The fuel pump according to claim 8 , wherein
the fixing portion is plastically deformed to press the engaging portion of the cylinder.

Assignees

• Hitachi Astemo Ltd

Inventors

• Tamura Shingo
• Usui Satoshi
• TOKUMARU Kazuaki

Classifications

• F02M59/04 Primary

  characterised by special arrangement of cylinders with respect to piston-driving shaft, e.g. arranged parallel to that shaft {or swash-plate type pumps (with rotary valve F02M59/362)} · 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

• F02M59/485

  Means for fixing delivery valve casing and barrel to each other or to pump casing · CPC title

• F02M59/48

  Assembling; Disassembling; Replacing · CPC title

• F02M2200/8053

  involving mechanical deformation of the apparatus or parts thereof · CPC title