某车型副车架与车身连接螺栓断裂分析及夹紧力校核  

Fracture Analysis and Clamping Force Check of Sub-Frame and Car Body Connecting Bolt in a Certain Car

作　　者：梁鹏 王迪 周志成 LIANG Peng;WANG Di;ZHOU Zhicheng(Auto Engineering Research Institute,BYD Auto Industry Co.,Ltd.,Shenzhen Guangdong 518118,China)

机构地区：[1]比亚迪汽车工业有限公司汽车工程研究院,广东深圳518118

出　　处：《汽车零部件》2022年第2期67-72,共6页Automobile Parts

摘　　要：采用宏观观察、化学成分分析、金相试验、力学性能检测、摩擦因数测试、模拟装配试验、夹紧力测试及校核,对某车型副车架与车身在现场装配过程中出现的螺栓断裂进行了分析。分析表明:螺栓材料质量符合标准要求,属于过载断裂。主要原因为油脂对摩擦因数的影响,当摩擦因数减小后,原装配扭矩会导致螺栓受到的轴力增大,超过其本身强度极限发生断裂。此外,由于设计的原因,装配过程安装表面的平整度、装配公差均会对装配质量产生较大影响,调整原装配工艺,对产生的夹紧力进行校核。结果表明:调整后的装配扭矩可满足使用要求,但在实际装配过程中仍要避免各种改变螺纹摩擦因数的外界因素。The bolt fracture of a car sub-frame and car body in the field assembly process was analyzed by macroscopic observation,chemical component analysis,metallographic examination,testing of mechanical property,friction coefficient,assembly process simulation and clamping force check.The analysis shows that the quality of the materials meets the standard requirements and belongs to overload fracture.The main reason is the influence of grease on the friction coefficient.When the friction coefficient decreased,the axis force increased,and made the fracture happen when the load exceeded the ultimate strength of bolt at the same torque.In addition,because of design reasons,the flatness and tolerance of the mounting surface had a great impact on the assembly quality in the assembly process.The original assembly process was adjusted and clamping force was checked.The results show that the adjusted assembly torque can meet the requirement,but various external factors that change the thread friction coefficient should still be avoided in the actual assembly process.

关 键 词：过载 摩擦因数 夹紧力 油脂 

分 类 号：U466[机械工程—车辆工程]