曲轴滚压的显式动力学分析

Explicit Dynamic Analysis of Crankshaft Rolling Process

建立了曲轴圆角滚压的显式动力学分析模型,得到了圆角部位应力沿层深分布规律,研究了进给量和滚压道次对残余应力分布以及数值方面的影响。结果表明:圆角滚压后产生了足够强度和分布区域的轴向压应力,有利于抵消曲轴工作状态下由弯曲载荷所产生的拉应力;残余压应力在一定范围内随进给量增加逐渐增加,此后随进给量增加不升反降;残余压应力在滚压过程中小幅波动,随滚压道次增多残余压应力波动范围逐渐减小,最后趋于稳定,增加滚压道次的意义在于稳定和保持已获得的残余压应力。揭示了圆角滚压可显著提高曲轴弯曲疲劳强度的原因所在,提供了理想进给强度和滚压道次的分析计算方法,为曲轴滚压工程实际合理选择工艺参数提供了参考和理论支撑。

Explicit dynamic analyzing model of crankshaft rolling is established and the stress distribution regularities along fillet layer depth are obtained. Influences on distribution regularities and numerical value of residual stresses from feeding amount and rolling passes are studied. The results show that, compressive stresses of axial direction possess sufficient strength and have enough distributing areas after fillet rolling, while these compressive stresses are propitious to counteracting the draw stresses which are caused by ben- ding loads in crankshaft working condition; Residual compressive stress increases with feeding amount gradually in a certain range, then residual compressive stress does not increase but decrease with increas- ing the feeding amount; Residual compressive stress fluctuates slightly during the rolling process and the fluctuating range is decreased with increasing the rolling passes, finally, the residual stress is stabilized. The increasing of rolling passes can make for stabilize and maintain residual compressive stress which has been attained by rolling. This paper reveals the reason why fillet rolling can significantly enhance crank- shaft bending fatigue strength and provides analysis and calculation methods for perfect feeding amount and reasonable number of rolling passes. References and fundamental theories about how to select technological parameters for crankshaft rolling process, are also provided in this paper.