拖拉机最终传动被动齿轮失效分析

小四轮拖拉机最终传动被动齿轮的失效多以轮齿折断为主,通过对20CrMnTi钢渗碳、碳氮共渗和球墨铸铁等温淬火三种工艺的失效件分析,发现齿面严重刀痕是主要原因,因其在随后处理或承载过程中由应力集中而诱发了裂纹的产生和发展。另外,由于热处理工艺和材料成分中合金元素不足等问题,致使受力部位出现不良组织,也进一步降低了机件的承载能力。

Failure Analysis on Final Driven Gear of Tractors

The failure most belongs to the teeth's rupture for the final driven gear of tractors.By means of analyzing for the failed gears with 20CrMnTi steel in carburizing,carbonitriding and spheroidal graphite cast iron in austempering,the main reason has been found for the most rough cutter marks on the teeth's surface,because the creating and developing of the creak would be caused by the stress concentration in the following processing and load-bearing.In addition,other problems such as the technologies of heat treatment,the lack of alloying agent in the material also lead to appear the unnormal microstructure in the load-supporting part of the teeth,and they also decrease the gear's performance.