Preparation method of precision forging billet for external input shaft Ⅱ of automobile DCT automatic transmission

Abstract

The invention provides a manufacturing method for a precisely-forged blank of an input shaft II of an automatic dual clutch transmission (DCT) of an automobile. Surface grinding, lubricant spraying and drying are conducted on a material section, cold diameter reduction treatment is conducted on the material section in a grinding tool, and the material section is heated to 1000 DEG C-1080 DEG C in a protective atmosphere; blank forming and heading are conducted on a press machine, and a hot manufactured blank piece is obtained; a concave guide groove with the depth being 5-8 mm is pre-forged; then hot extrusion is conducted, a deep hole with the aperture ratio being smaller than or equal to 4.5 is formed through extrusion, and the bottom thickness of the deep hole is greater than or equal to D / 2; isothermal annealing is conducted, shot blasting is conducted then, and phosphorization and saponification are conducted on the surface; a cold extrusion machine is used, and the final forged blank is obtained; and machining and distressing heat treatment are conducted. According to the method, the inner hole is formed through extrusion, the metal flow line is reserved, mechanical strength is improved by 25%, and the phenomenon that a bevel gear on the input shaft II is stressed and consequently the tube wall is broken can be prevented effectively; the material utilization rate is increased by 22%, and machining efficiency is improved substantially; the quality of manufactured products is stable, batch production efficiency is improved, and the requirement for domestic production of the automatic DCT is met.

Description

technical field [0001] The invention belongs to the field of metal parts processing, and relates to a method for preparing an input shaft II precision forging blank of an automobile DCT automatic transmission. Background technique [0002] DCT is the abbreviation of Dual Clutch Transmission in English, literally translated as "dual clutch transmission" in Chinese, and the input shaft of DCT automatic transmission is a very critical part in dual clutch transmission. The DCT automatic transmission has advantages over the traditional automatic transmission in terms of efficiency and cost. There are two input shafts on the DCT automatic transmission, one inner input shaft I and one outer input shaft II. The two hollow shafts are sleeved together to transmit engine power. Two input shafts, corresponding to clutches "1" and "2". There are second, fourth and sixth gear meshing gears on the outer input shaft II, which play the role of power transmission. [0003] In recent years,...

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Problems solved by technology

[0004] Aiming at the insufficient strength of the tubular shafts produced by the existing processing technology, the risk of fracture and the low utilization rate of materials in processing, the present invention provides an external input shaft II (hollow shaft) suitable for industrialized manufacturing of automobile DCT automatic transmissions. class) manufacturing method

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