Production method for second gears of automatic automotive transmissions

Abstract

The invention provides a production method for second gears of automatic automotive transmissions. According to the production method, pre-forging blanks are subjected to cold extrusion after being produced by isothermal forging. The production method is characterized in that the inclination of the inner walls of modified grooves of the pre-forging blanks is 2-4 degrees larger than that of finish-forging blanks. Products produced by the production method are high in accuracy and low oxidizing, good internal structure of metal is realized, crystal grains are fine, and poor textures such as coarse crystals and mixed crystals are avoided; equipment as needed is low in tonnage and small in forming fore, filling of tooth profile is easy, unit pressure borne by molds is remarkably reduced, and service life of the molds are quite long; product hardness reaches HB130-150, and metal structure reaches the second level; the tooth profile is fully filled and does not deform during heat treatment after cold extrusion forming.

Description

technical field [0001] The invention belongs to the field of metal processing, and relates to a preparation method of gears in a power transmission transmission system of an automobile automatic transmission (DCT), in particular to a preparation method of shift teeth of an advanced automatic transmission of automobiles. Background technique [0002] Automobile automatic transmission (DCT) shift gear is an important part of automobile automatic transmission. It plays the role of shifting and shifting gears. It includes recessed grooves, and the synchronous teeth are all sunk in the grooves. The quality of its production is directly related to the quality of the car. safety and passenger comfort. [0003] In the prior art, the shift gears of the DCT automatic transmission are usually machined by lengthening the gear wheelbase. First, the wheelbase is lengthened to increase the size of the blank, which increases the consumption of materials. Secondly, the synchronous tooth shap...

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Problems solved by technology

[0003] In the prior art, the shift gears of the DCT automatic transmission are usually machined by lengthening the gear wheelbase. First, the wheelbase is lengthened to increase the size of the blank, which increases the consumption of materials. Secondly, the synchronous tooth shape is processed by machine tool gear shaping and milling for a long time. It increases its manufacturing cost; and the precision is not too high, which reduces the smooth flexibility of shifting and also reduces the interchangeability of gears

In addition, this kind of mechanical processing method requires a large machining allowance, and the previous process basically needs to reserve enough machining allowance. The size required for the shift gear blank is too large, and the metal raw materials consumed are relatively large. Secondly, this kind of mechanical processing method is prone to waste products in multi-channel mechanical processing procedures, and the scrap rate of parts is high, which also increases its manufacturing cost.

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