Cold extrusion forming process of helical gear

Abstract

The invention discloses a cold extrusion forming process of a helical gear. The cold extrusion forming process specifically comprises the following steps: (1) spheroidizing annealing, shot blasting and phosphorus saponification treatment are sequentially conducted on a bar; (2) the bar treated in the step (1) is placed in a cold extrusion die to enable the bar to form a forming blank with a required spiral gear groove; (3) the formed blank in the step (2) is placed in an upset-extrusion forming die, the head of the blank is upset, and a forged piece is obtained; and (4) the forged piece in thestep (3) is subjected to isothermal normalizing treatment, so that the gear meets the technical requirements of products. According to the preparation method, a rotary lower die structure is adopted,a lower die freely rotates under the action of radial force generated when materials flow, and therefore the requirement for forming a spiral angle is met; the extrusion speeds of three strokes are adopted, so that the gear profile of a part is completely filled; and two sets of hydraulic systems are adopted, so that elastic deformation and friction deformation of gear sides caused by demolding are eliminated.

Description

technical field [0001] The invention relates to a technology in the field of cold extrusion of gears, in particular to a cold extrusion forming process of helical gears. Background technique [0002] Gears are widely used in automobile transmission. Because the helical gear has a spiral groove, its structure is complex, and the gear precision is high. At present, the main processing methods such as hobbing, shaping, grinding or honing are used, but the following problems exist in machining: many processes, low material utilization, The processing efficiency is slow and the production cost is high. [0003] The use of cold extrusion molding can make up for the lack of mechanical processing. Through the movement of equipment pressure, the bar to be extruded is pressed into the cavity with spiral tooth grooves, and the metal material flows along the tooth grooves to form helical gears. This cold extrusion method can be divided into non-resistance extrusion and resistance extr...

AI Technical Summary

Problems solved by technology

Because the helical gear has a spiral groove, its structure is complex, and the gear precision is high. At present, the main processing methods such as hobbing, shaping, grinding or honing are used, but the following problems exist in machining: many processes, low material utilization, Slow processing efficiency and high production cost

This forming method is still a form of one-way force in essence. The force of the spring depends on the output force of the hydraulic system of the equipment and cannot be adjusted according to the actual situation. Tests have proved that this structure still has tooth shape and tooth direction. Insufficient situation

In addition, because the type and strength of the spring cannot be accurately selected through calculation, the stability of the extrusion molding quality will be affected due to the aging of the spring in mass production

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