Prediction and experimental study on thermal stress in multi-tooth form grinding of cycloid gear

Cycloid gear is an important transmission part of RV reducer of robot. Its surface mechanical properties significantly affect the precision and life of robot. During the forming and grinding process of the cycloid, the temperature gradient of the tooth surface changes greatly, resulting in residual stress, which is very important to the yield limit and service life of the cycloid. The thermal-mechanical coupling model of cycloid wheel grinding is established by using moving heat source method and load step loading method. The magnitude and direction of the first, second, and third principal stresses are obtained by calculating the Mises equivalent stress in the three-dimensional space of the grinding area. The temperature field and thermal stress of multi-tooth form grinding are simulated by finite element method, and the influence of grinding parameters on stress distribution is analyzed. The X-ray method is used to detect the residual stress of cycloid gear in form grinding, and the variation law of residual stress on the tooth surface under different process parameters is analyzed, and the change trend is basically consistent with the simulation results. The results show that the grinding process parameters can be optimized by theoretical calculation and finite element simulation, which can effectively reduce the residual tensile stress and increase the residual compressive stress. A method for predicting the residual stress of the cycloid gear form grinding is proposed, which provides a basis for the selection of the process parameters of the cycloid gear form grinding