面齿轮磨削齿面力热耦合及残余应力研究

Research on Thermo-Mechanical Coupling and Residual Stress on Tooth Surface of Face Gear Grinding

根据面齿轮磨削残余应力的产生机理和Prandtl-Reuss方法,建立磨削表层热弹塑性力学本构关系;基于面齿轮磨削方法和Gleason接触原理,得出碟形砂轮磨削点接触椭圆方程参数、磨削力和磨削热流量的数学模型。构建面齿轮磨削单齿3D有限元模型,采用小步距移动法模拟磨削载荷的移动,仿真磨削温度场,得到磨削瞬态最高温度位于磨削接触弧中心区域。采用力热耦合间接法仿真分析了磨削表层残余应力,得出磨削齿面上为残余压应力,齿面里层为残余拉应力;随磨削深度和砂轮速度增大,齿面残余应力增加显著;但随展成速度增大,齿面残余应力增幅减小。采用X射线衍射法实验,对比分析了面齿轮磨削表层残余应力的实测值与仿真值,其相对误差最大值17.8%在精度控制范围内,说明力热耦合有限元分析残余应力有效,为改善面齿轮磨削质量提供了依据。

According to the generation mechanism of grinding residual stress of face gear and the method of Prandtl-Reuss,a constitutive relation of thermal elastic-plastic mechanics of grinding surface has been established.Based on the grinding method of face gear and GLEASON contact principle,the mathematical models of point contact ellipse equation parameters,grinding force and heat flow of disc wheel grinding were obtained.The method of small sub-step movements was adopted to simulate movements of grinding loads by means of 3D finite element model of single tooth of the face gear.Grinding temperature fields were simulated,and the highest transient temperature was located in the center of grinding contact arc.Grinding surface residual stresses were simulated and analyzed by indirect method of thermo-mechanical coupling,and many simulation conclusions were obtained.Firstly,compressive residual stresses were located on grinding tooth surface,and tensile residual stresses occurred in the tooth layer.Secondly,tooth surface residual stresses increased significantly with the increasing of grinding depth and disk wheel speed,while enhanced slightly with the increasing of generating speed.X-ray diffraction method was adopted to compare and analyze the measured values and the simulated ones of the surface residual stress,and the maximum relative error of 17.8%was within the precision control range.It showed that the finite element analysis of thermo-mechanical coupling of residual stress was effective,and it provided a basis for improving the grinding quality of face gears.