High-pressure pump and production method thereof

Patent metadata

Field	Value
Publication number	US-2018010602-A1
Application number	US-201515543778-A
Country	US
Kind code	A1
Filing date	Dec 22, 2015
Priority date	Jan 20, 2015
Publication date	Jan 11, 2018
Grant date	—

Abstract

A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. The pump body closes the pressure chamber on a side opposite to a plunger. The plunger reciprocates within the cylinder to vary a volume of the pressure chamber. The large-diameter portion provided at an end of the plunger on a side protruding to the pressure chamber has an outside diameter larger than an inside diameter of the cylinder and smaller than an inside diameter of the pressure chamber. In this case, the large-diameter portion is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

First claim

1 . A high-pressure pump comprising:
a cylinder; a pump body including a pressure chamber having a larger inside diameter than an inside diameter of the cylinder, the pressure chamber being disposed in a deep portion of the cylinder, the pump body closing the pressure chamber on a side opposite to the cylinder; a plunger that reciprocates within the cylinder to vary a volume of the pressure chamber; and a large-diameter portion having an outside diameter larger than the inside diameter of the cylinder, and smaller than the inside diameter of the pressure chamber, the large-diameter portion being provided at an end of the plunger on a side protruding to the pressure chamber.

2 . The high-pressure pump according to claim 1 , wherein,
as a result of at least either “heating the cylinder” or “cooling the large-diameter portion”, the cylinder and the large-diameter portion has a relationship such that the inside diameter of the cylinder is larger than the outside diameter of the large-diameter portion, or the outside diameter of the large-diameter portion is smaller than the inside diameter of the cylinder.

3 . The high-pressure pump according to claim 1 , wherein:
the cylinder and the pump body are formed integrally; and as a result of at least either “heating the pump body and the cylinder” or “cooling the large-diameter portion”, the cylinder and the large-diameter portion has a relationship such that the inside diameter of the cylinder is larger than the outside diameter of the large-diameter portion, or the outside diameter of the large-diameter portion is smaller than the inside diameter of the cylinder.

4 . The high-pressure pump according to claim 1 , wherein:
the large-diameter portion and the plunger are formed integrally; and as a result of at least either “heating the cylinder” or “cooling the large-diameter portion and the plunger”, the cylinder and the large-diameter portion has a relationship such that the inside diameter of the cylinder is larger than the outside diameter of the large-diameter portion, or the outside diameter of the large-diameter portion is smaller than the inside diameter of the cylinder.

5 . The high-pressure pump according to claim 1 , wherein:
the large-diameter portion and the plunger are formed integrally; the cylinder and the pump body are formed integrally; and as a result of at least either “heating the pump body and the cylinder” or “cooling the large-diameter portion and the plunger”, the cylinder and the large-diameter portion has a relationship such that the inside diameter of the cylinder is larger than the outside diameter of the large-diameter portion, or the outside diameter of the large-diameter portion is smaller than the inside diameter of the cylinder.

6 . The high-pressure pump according to claim 1 , wherein:
the large-diameter portion and the plunger are made of different materials; and a linear expansion coefficient of the large-diameter portion is larger than a linear expansion coefficient of the plunger.

7 . A production method for producing the high-pressure pump according to claim 1 , the method comprising:
a temperature control process for performing at least either “heating the cylinder” or cooling the large-diameter portion” to allow the inside diameter of the cylinder to become larger than the outside diameter of the large-diameter portion, or allow the outside diameter of the large-diameter portion to become smaller than the inside diameter of the cylinder; an insertion process for inserting the plunger into the cylinder; and a normal temperature control process for allowing resultant temperatures of the cylinder and the large-diameter portion to approach temperatures of the cylinder and the large-diameter portion before the temperature control process.

Assignees

• Denso Corp

Inventors

• Nakaoka Masaharu

Classifications

• F04B53/14

  Pistons, piston-rods or piston-rod connections · CPC title

• B21D39/04

  of tubes with tubes; of tubes with rods {(crimped pipe joints as such F16L13/14)} · CPC title

• F04B19/22

  of reciprocating-piston type · CPC title

• F02M59/26

  caused by movements of pistons relative to their cylinders · CPC title

• F04B53/16 Primary

  Casings; Cylinders; Cylinder liners or heads; Fluid connections · CPC title