Abstract: The motor gear cover of automobile wiper system is generally made by injection molding technology, and glass fiber is added into raw material to enhance strength of product. Taking the strength of screw hole of motor gear cover as the research object, firstly, the mold flow analysis software Moldflow is used to analyze the forming process of the original scheme, and it is found that there are weld marks on the edge of the screw hole, and the strength did not meet the design requirements combined with the torque test; then the design scheme is optimized and the screw hole is thickened by radial direction; finally, the assembly test and crushing force test are compared and verified before and after optimization. The results show that the supporting capacity is increased 100% when radial thickness is added by 2 mm, and the assembly torque is increased from 1.75 Nm to 2.1 Nm, which meet the design requirement and provide the refence for strength design of glass fiber enhanced material.

Key words: Welding; Defects; Motor gear cover; Glass fiber; Moldflow analysis; Strength; Crushing force

摘要： 汽车雨刮电机齿轮盖通常采用注塑成型技术，在材料中加入玻璃纤维增加成品强度。 以电机齿轮盖的螺钉孔强度为研究对象，首先，利用模流分析软件 Moldflow 对原始方案进行 成型过程分析，发现螺钉孔边缘存在熔接痕，结合力矩试验确认强度未满足设计要求；然后 对设计方案进行优化，对螺钉孔进行径向加厚处理；最后对优化前后方案进行装配试验和压 溃力试验对比验证。结果表明，螺钉孔径向增加 2 mm，承载能力增加 100%，装配力矩从 1.75 Nm 提高到 2.1 Nm，满足设计要求，为玻璃纤维增强材料的强度设计提供了参考。

关键词: 熔接；缺陷；电机齿轮盖；玻璃纤维；模流分析；强度；压溃力