High-pressure fuel supply pump and the manufacturing method

Abstract

An object of this invention is to provide such a welded structure of and welding method for two metallic parts fitted together at a tubular section in a high-pressure fuel supply pump, that enables rapid joining of both metallic parts by staking (press-fitting included), screw fastening, and / or laser welding, offers high welding strength and sufficient fluid sealability, and keeps the metallic materials free from thermal changes in composition. While an electric current is supplied to any one of the welding connection surfaces formed between a pump housing and cylinder in a high-pressure fuel supply pump, between the pump housing and an installation flange, between the pump housing and an intake or discharge joint, between the pump housing and a pulsation-absorbing damper cover, between the pump housing and a relief valve mechanism, and between the pump housing and an electromagnetically driven intake valve mechanism, the particular two sections are pressed against each other to generate, along the connection surface, a plastic flow not causing melting or fusion due to heat, and form a diffusion-weld region at the connection surface by using the plastic flow and the application of the pressure.

Description

technical field [0001] The present invention relates to a high-pressure fuel pump and a manufacturing method thereof, and particularly relates to a joining structure in which two metal members are fitted in an annular or cylindrical portion and welded at the fitting portion. Background technique [0002] JP-A-2005-342782 and JP-A-2004-17048 are known as techniques for fitting a cylindrical member into a hole of a cylindrical portion and welding two metal members. [0003] According to this, a technique is described in which two metals are joined by applying current to a fitting portion while applying pressure. [0004] On the other hand, the joint structure of the pump body and the pump casing of the high-pressure fuel pump is known as follows: fixing of fasteners at the sealing part for forming metal contact between the two (WO2002 / 055881 International Publication) and pump After the outer periphery is sealed by pressing, the end of the pump body and the pump casing are ri...

AI Technical Summary

Problems solved by technology

[0010] In the high-pressure fuel supply pump, there is a problem that, for example, the pump body and the pump casing always have a place where two cylindrical members are fitted and joined together.

However, in these joint structures, the fluid tightness and joint strength are not sufficient. Especially in the case of laser welding, the composition of the material itself changes due to heat, and the magnetic properties change randomly before and after joining. Therefore, It is not suitable for the part of the magnetic circuit. In addition, it causes the dimensional change of the member due to thermal deformation before and after joining, and cannot maintain the original design size.

Images