转向节静拉强度失效的原因分析和优化

Failure Analysis and the Optimization for the Static Pull Test of Steering Knuckle

支撑车轮轴承的悬架零件被称为车轮支架。当车轮支架用在转向桥上时,也可称为“转向节”[1]。因为转向节的特殊的安全性,主机厂/配套厂需要完成台架等一系列试验,静拉试验就是其中关键的一项。本文主要结合实际案例,针对转向节的转向臂静拉试验失效原因,从石墨球数以及石墨形状对铸造的机械性能的影响的角度,做详细的分析。针对相关缺陷,设计新的铸造工艺冒口,然后通过有限元计算,对优化后的工艺进行模流分析。确认方案可行之后,试制新的样件,然后对其进行试验验证。经过分析和试验验证,可以得出:1) 石墨球数、石墨形状对零件的机械性能影响很大;2) 在不改变化学成分的前提下,通过改善冒口位置,可以有效改善零件的石墨球数、形态和大小。

The suspension parts that support the wheel bearings are called knuckle[1].When the wheel knuckle is used on the steering bridge,it is also called the“steering knuckle”.Due to the special safety of the steering knuckle,most of the OEM needs to complete a series of tests such as bench test,among which static pull test is the key one.In this article,combined with the actual case,aiming at the steering arm static tension test failure reason of knuckle,we analyze the influenced factors,including the number and the shape of the graphite ball on the casting of mechanical properties.Then aiming at the relative defects,a new foundry process was designed,and then the optimized process was analyzed by finite element method.After confirming the feasibility of the scheme,we trial-produce the new sample,and then test and verify it.After analysis and experimental verification,it can be concluded that:1)the number of graphite balls and the shape of graphite have a great influence on the mechanical properties of the parts;2)on the premise of not changing the chemical composition,the number,shape and size of graphite balls can be effectively improved by improving the riser position.