Process for manufacturing heavily stressed valve spring

Abstract

The invention provides a manufacturing process used for a high-stress valve spring, which can improve the quality and product qualification ratio of the spring product, reduce the production cost of the spring and comprises the processes as follows: spring rolling: steel wire blanks are rolled and made into semi-finished springs; primary temper: the spring is tempered at low temperature so that the stress is removed; spring grinding: two end surfaces of the spring are grinded so as to achieve the required length; chamfering: the burrs of the grinded spring are removed; stress optimization: secondary temper: the spring is tempered again at low temperature so that the stress is removed; shot blasting which is used for prolonging the service life of the spring; hot-pressing; load classification: the spring with bad load is removed and the product with qualified load is used as the high-stress valve spring product; oiling: the high-stress valve spring is oiled; and is prepared for packaging. The process improves the quality and the qualification ratio of the spring product and reduces the production cost of the spring as the working procedure of length classification is saved and the stress optimization process is arranged after the process of spring grinding and chamfering in the traditional process.

Description

technical field [0001] The invention relates to a manufacturing process of a valve spring, in particular to a manufacturing process of a high-stress valve spring. Background technique [0002] High-stress valve springs are used in supercharged gasoline direct injection automotive engines. This type of engine has low fuel consumption and high power, which can reach more than 110 kilowatts. Therefore, high-quality, low-cost high-stress valve springs are required. [0003] see figure 1 , figure 1 Process flow chart for conventional high stress valve spring manufacturing. [0004] The manufacturing process of traditional high-stress valve springs is: [0005] Coil spring → stress optimization (SOF in the industry) → tempering → length sorting → spring grinding → chamfering → first shot peening → second shot peening → hot pressing → load classification → oiling. [0006] The main steps in the above flow will be described below. [0007] The coil spring process is to roll th...

AI Technical Summary

Problems solved by technology

[0017] 1. In the above process, there are two processes to obtain the spring with the required free length, that is, the length sorting process and the spring grinding process. The spring with too long free length can be ground by grinding the two end faces of the spring in the spring grinding process. The required length is reached, but because the springs with free lengths that are too long or too short have been removed (as waste products) in the previous length sorting process, the effect of the spring grinding process has not been fully utilized, and the scrap rate is high , which directly increases the manufacturing cost of the product

[0018] 2. In the operation of the above process, in the process of identifying and removing springs with too long or too short free lengths in the length sorting process, there will be phenomena that affect the concentricity of the product, the movement of the helix angle, and the fluctuation of the free length of the spring , affecting the quality of spring products

[0019] 3. Stress optimization (SOF) in the above-mentioned process is placed directly after the coil spring process. Because waste products may appear in the subsequent length sorting, spring grinding, and chamfering processes, they are rejected, and these scrapped The products are all processed through the stress optimization process, which also causes a factor of high manufacturing costs

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