Method for casting copper sleeve and piston into whole

Abstract

The invention discloses a method for casting a copper sleeve and a piston into a whole. The copper sleeve and the piston are cast into a whole by adopting an extrusion casting technology. Firstly, a mold is installed on an extruder in the extrusion process of the piston, the processed copper sleeve semi-finished product is arranged on a pin hole shaft of a piston extrusion model; aluminum melt is fully cast into a cavity, and extruded and cast, so that the copper sleeve semi-finished product and the piston are cast into a whole. The method comprises the following steps: 1, processing the copper sleeve semi-finished product according to a piston product drawing; 2, cleaning the copper sleeve semi-finished product, putting the cleaned copper sleeve semi-finished product into an electric furnace, preheating the copper sleeve semi-finished product, installing the copper sleeve semi-finished product on the pin hole shaft of a piston model, casting the aluminum melt into a piston cavity, and extruding and casting at the specific pressure of over 90Mpa; 3, carrying out heat treatment and machining on a piston product cast with the copper sleeve, and checking out to form the product. The piston produced by the method does not affect the matching precision of the piston and the cylinder due to the copper sleeve in operation of an engine, and the copper sleeve and a pin boss hole of the piston are tightly combined, and firm and reliable.

Description

Technical field [0001] The invention relates to a method for casting a copper sleeve and a piston into one body, and belongs to the technical field of mechanical casting. Background technique [0002] The requirements of modern piston internal combustion engines for the pistons used are: small specific gravity, high temperature resistance and wear resistance. Now most pistons are made of aluminum alloy as raw material and are made by gravity casting. Because aluminum alloy has poor pressure resistance and wear resistance, especially the piston pin seat hole bears high pressure, and the lubrication condition in the pin hole is not good. Therefore, the wear is fast, which affects the technical performance and service life of the engine. In order to solve this problem, many high-performance engines have a wear-resistant copper sleeve in the piston pin hole seat. However, how to install this kind of copper sleeve into the piston pin seat hole is a difficult problem that is not easy ...

AI Technical Summary

Problems solved by technology

[0006] This method of using interference fit between the copper sleeve and the piston pin seat hole has the following disadvantages: 1. If the interference is slightly large, the copper sleeve will have a large expansion during the operation of the engine under high temperature and high pressure, which will make the piston pin The increased deformation of the hole will reduce the matching accuracy of the piston and the cylinder liner, resulting in a decrease in power and accelerated wear of the two. What's more, it will increase the amount of out-of-round inner diameter of the copper sleeve, which will kill the floating piston pin;

[0007] 2. If the interference is slightly small, the copper sleeve and the pin seat hole will not fit tightly when the engine is running, resulting in relative rotation or axial movement, and even cylinder strain;

[0009] 4. There are many processes, which will increase the cost and reduce the production efficiency

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