浅谈汽缸体曲轴孔加工导致曲轴抱死原因

Discussion of the Cause Leading the Locked on Crankbore During the Cylinder Producing

针对曲轴孔台阶导致发动机曲轴抱死,其表现为缸体曲轴孔加工成品时所有尺寸都是合格的,但拆下轴承盖再装上后轴承盖与缸体结合面错位产生台阶。经过生产过程分析及曲轴孔轴承盖安装拧紧的特点得出产生台阶的根本原因:安装工艺不合理、拧紧时摆动、拧紧程序不完善。通过问题的分析,同时发现了轴承盖结合面不平行、螺纹孔有铁屑、精加工前轴承盖受到撞击、轴承盖结合面侧面过小同样会引起曲轴孔台阶,并根据以上原因做出改进。

For all the locking crankbore, measure all the size is good, but after disassemble the main bearing cap then assemble again, the locking comes. After analyse the process and the features in tightening the main bearing cap, we find some route causes： the assemble process and the tightening program is not reasonable, part＇s have some moving when tightening. Through the probrem analyse, some other causes have been found, like： the main bearing cap is not parallel, some chip in the threaded hole, hitting before finish cutting and the main bearing cap face undersize also will lead to lock, so we do some improvements base on the above causes.