Side extrusion forming method of parking gear tooth profile

Abstract

The invention discloses a lateral extrusion forming method of a parking gear tooth shape, which comprises the steps of sequentially blanking, forging, normalizing, rough turning, first shot blasting, lubricating, cold extrusion, finishing turning, carburizing and quenching, and In the second shot blasting process, in the forging process, the blanked material is forged to initially form rectangular teeth to obtain a prefabricated billet with concave grooves formed on both sides of the tooth root of the rectangular tooth; in the cold extrusion process, the prefabricated billet is It is placed in a cold extrusion die and extruded at room temperature. The cold extrusion die includes a plurality of movable modules that are uniformly arranged along the circumferential direction. When the mold is closed, the rear end of the movable module is subjected to a force, which pushes the movable module to move in the radial direction, and each movable module gradually closes, thereby extruding the prefabricated blanks in the annular annular cavity laterally. The metal blank is extruded into the concave groove along the radial direction, and fills the concave groove to complete the rectangular tooth finishing extrusion.

Description

technical field [0001] The invention relates to the technical field of automobile parts processing, in particular to a lateral extrusion forming method of a parking gear tooth profile. Background technique [0002] The current pure electric or hybrid new energy vehicles are equipped with an electric drive powertrain. The electric drive powertrain includes a motor and a reducer. The output shaft (or rotating shaft) of the motor is connected to the input shaft of the reducer to transmit torque. [0003] Among the existing reducers, some are equipped with a parking gear for braking when the vehicle is stopped to prevent the vehicle from rolling away (P gear), and when the parking gear is locked, the transmission part can be prevented from rotating. The parking gear is generally arranged on the intermediate shaft or the output differential, which bears a large torque and impact load. Once the tooth surface pitting or tooth root crack failure occurs, it will lead to serious conse...

AI Technical Summary

Problems solved by technology

[0004] The parking gear is generally made of prefabricated blanks by hot forging process, finished car after isothermal normalizing, the outer circular rectangular teeth of the parking gear are processed by gear hobbing, and then the pin spline is passed through, and finally the gear is ground after carburizing and quenching. shape; the precision of the gear reaches level 6, so the processing cost is relatively high. Currently, the cold extrusion or cold finishing process is used to replace the gear hobbing process, which can greatly reduce the gear processing cost. However, there are still the following technical problems:

[0005] 1. In the process of cold extrusion, if a cylindrical blank with a smaller diameter is directly selected for direct cold pressing, that is, the diameter of the blank is very close to the diameter of the root circle of the small end, and the ratio of the height to diameter of the blank is too large, the blank is prone to bending instability , resulting in longitudinal bending, one-sided flow phenomenon, and large lateral force, which not only affects the accuracy of the parts, but also easily damages the mold;

[0006] 2. During the cold extrusion process, since the metal is easy to accumulate in the tooth groove of the parking tooth during cold pressing, and the metal flow is difficult, the defect of insufficient filling is likely to appear near the tooth root of the parking tooth, and a large flash is generated , causing a sharp increase in forming force, unable to extrude into the desired shape, reducing product quality

Images