Manufacturing technology of high-stress valve spring

Abstract

A manufacturing technology of a high-stress valve spring is a manufacturing technology which improves the spring product quality and qualification rate and decreases the spring production cost. The manufacturing technology comprises the following processes: spring coiling, namely, coiling a steel wire blank into a semi-finished spring; first annealing, namely, annealing the spring under low temperature to remove stress; spring grinding, namely, grinding two end surfaces of the spring to reach the required length; chamfering, namely, removing burrs on the spring after grinding; stress optimizing; secondary annealing, namely, annealing the spring under low temperature to remove stress again; shot blasting, namely, prolonging the fatigue life of the spring; thermal pressing; load classifying,namely, removing the spring with ultralow load, and treating the product with qualified load as the high-stress valve spring product; and oil coating, namely, coating the high-pressure valve spring product with oil, and preparing for packing. According to the manufacturing technology of the high-stress valve spring, the process of sorting based on length is saved and the process of optimizing stress is performed after the ball grinding process and the chamfering process in a traditional technology, so that the spring product quality and qualification rate can be improved; and the spring production cost is decreased.

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...

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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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