精油分离器自攻螺钉无法拧紧到底失效分析

Failure Analysis of Self-Tapping Screw Unable to Tighten to the Bottom for Essential Oil Separator

通过装配拧紧曲线的分析,精油分离器自攻螺钉无法拧紧到底的原因是拧紧扭矩不足(图纸定义为4 N·m,部分贴合扭矩已>4 N·m)。对精油分离器的孔径、含水率及硬度进行试验分析,结果表明,材料的硬度、贴合扭矩和破坏扭矩随含水率增加而减少。参考自攻螺钉拧紧技术标准,对该连接的工艺扭矩进行计算,6 N·m是最适合该连接点的工艺扭矩,同时应控制精油分离器的含水率,建议的含水率状态为1.5%~3%。

Through the analysis of the assembly tightening curves, the reason that the self-tapping screw of the essential oil separator cannot be tightened to the bottom is insufficient tightening torque(defined torque in the drawing is 4 N·m but some joint torques are higher than 4 N·m). The pore diameter, moisture content and hardness of the essential oil separator are tested and analyzed. The results show that the hardness, joint torque and breaking torque of the material decrease with the increase of moisture content. According to the tightening standards of self-tapping screw, the process torque of the connection is calculated, and it is concluded that 6 N·m is the most suitable process torque for the connection point. At the same time, the moisture content of the essential oil separator should be controlled and the recommended moisture content state is 1.5%~3%.