【作者】 王晋；

【导师】 付景顺；

【作者基本信息】 沈阳工业大学 ， 车辆工程， 2010， 硕士

【摘要】 驱动桥桥壳是汽车主要的承载件和传力件,汽车在行驶过程中,驱动桥壳承受复杂的载荷。尤其是当汽车通过不平路面时候,由于车轮与地面间产生的冲击载荷,在设计不当或制造工艺有问题时,会引起桥壳的变形和折断。此外,作用在驱动车轮上的牵引力和侧向力也是经过桥壳传到车架或者车身上。因此,驱动桥壳应具有足够的强度、刚度和良好的动态特性。受交变载荷的影响,桥壳容易发生疲劳破坏。疲劳破坏通常在没有明显预兆的情况下突然发生并造成严重事故。所以,有必要对桥壳进行疲劳寿命计算。本文以轻型货车驱动桥壳为研究对象,首先建立了驱动桥壳的有限元模型。之后对桥壳有限元模型进行了典型工况下的刚度和强度分析,得到了桥壳在各工况下的应力分布及变形情况。通过对桥壳的模态分析,得到了桥壳在自由约束状态下前15阶的振型和固有频率。利用疲劳寿命分析软件对桥壳进行垂直弯曲工况下的疲劳寿命计算,得到了桥壳的危险区域及该区域的寿命。分析结果表明：桥壳在各工况下的强度和刚度均满足要求,但在轴头法兰与半轴套管焊接处出现明显的应力集中；计算得到的最低固有频率远远大于路面的激励频率,因此,汽车行驶过程中,桥壳不会发生共振；桥壳危险部位的疲劳寿命也满足要求。最后,根据有限元分析结果对桥壳进行了结构改进,改进后桥壳在各工况下的应力值减少,桥壳危险部位的疲劳寿命也大大增加,应力集中情况有所缓解。更多还原

【Abstract】 The driving axle housing is main bearing part and force transforming part on automobile. The driving axle housing is bearing complicated load when vehicle is in motion, especially passing the rugged road. In case of improper designs or fabrication technology problems, the impact load between the wheel and the ground will bring about the deformation or break of driving axle housing. Furthermore, Tractive force and lateral force which use the driving wheel pass the automobile frame and the automobile body by driving axle housing. Therefore, driving axle housing should have enough strength and stiffness, and have a good dynamical property.Influenced by alternating load, fatigue breakdown happens easily to axle housing. Fatigue breakdown normally happens suddenly without any obvious symptom and bring out serious accident. So it is necessary to make fatigue life calculation to axle housing.This paper treats the light-duty truck driving axle housing as research object. Finite element model of driving axle housing is built firstly. Strength and stiffness of the finite element model of axle housing under typical working conditions is analyzed and stress distribution and deformation are obtained. The fifteenth modal shape and natural frequency under free state are obtained through modal analysis of axle housing. Dangerous area and its fatigue life are obtained by fatigue life calculation under vertical bending condition using fatigue life software.The result shows that strength and stiffness of axle housing under all working condition meet requirement, but there is an obvious stress concentration in weld region between flange and axle sleeve. The minimum frequency is larger than driving frequency of road, so axle housing can not have resonance during the driving. Fatigue life of dangerous part on axle housing can meet criterion too.Finally, axle housing structure is improved according to finite element analysis results. Axle housing stress under each working condition is reduced after improvement and stress concentration is relieved. Fatigue life of dangerous part on axle housing increased greatly.更多还原