某车型下摆臂连接螺栓滑丝问题分析及改进

Analysis and Improvement of Thread Failure of Connecting Bolt of Lower Swing Arm of a Vehicle

某型乘用车在厂内道路试验中,悬架系统下摆臂连接螺栓与副车架支架上的焊接螺母出现滑丝失效故障。为了分析并彻底解决滑丝问题,使用鱼骨图作为分析方法,从人、机、料、设、法、环、测等多个环节进行系统分析,并借助理化检验和试验验证,确定了螺栓滑丝的主要原因:一是焊接螺母内径尺寸超差,二是焊接螺母电泳处理后摩擦系数偏小,两者共同作用引起了螺栓及螺母滑丝。最后针对滑丝的关键影响因素,给出了合理的改进措施,防止了问题再次发生。

During the road test in the factory of a certain passenger car,the connecting bolt of the lower swi,ng arm of the suspension system and the welding nut on the subframe bracket has the problem of sliding wire failure.In order to analyze and thoroughly solve the problem of sliding wire,this paper uses fishbone diagram as the analysis method to systematically analyze from multiple links such as human,machine,material,equipment,method,ring and measurement,also through assistant inspection and test verification,determining the main cause of bolt sliding wire:on the one hand,the inner diameter of the welded nut is out of tolerance,and on the other hand,the friction coefficient of the welded nut after electrophoresis treatment is too small,the joint actions of the two cause the tightening force to be too large,thus causing the bolt and nut to slip.Finally,in view of the key influencing factors of wire slip,the author gives reasonable improvement measures to prevent the problem from reoccurring.