Microstructure Parameter Optimization Research Of Steel Ball Unfolding Wheel Based On Numerical Simulation

The unfolding wheel is the core component of the bearing steel ball detection wheeled unfolding mechanism.The slippage between the unfolding wheel and the steel ball reduces the detection efficiency of the steel ball,and the wear failure of the unfolding wheel increases the detection cost.In view of the above two problems,this thesis optimizes the geometric parameters(shape,size,depth,and spacing)of the pit microstructure on the surface of the unfolding wheel,and matches the best geometric parameters which increase friction and reduce wear(increase friction coefficient and reduce wear)of unfolding wheel.First,contact analysis is carried out to calculate the contact deformation between the steel ball and the unfolding wheel based on Hertz theory;Friction analysis is carried out to determine the friction type between the steel ball and the unfolding wheel,and the mechanism of increasing friction of the microstructure surface of the unfolding wheel is analyzed;The wear analysis is carried out to determine the main wear types of the unfolding wheel,and the wear reduction mechanism of the microstructure surface of the unfolding wheel is analyzed.Based on the Archard wear model,a method for calculating the wear depth of the microstructure unfolding wheel by finite element numerical simulation was obtained.Then,the orthogonal test design is carried out,and ABAQUS software is used to conduct the wear numerical simulation of the microstructure unfolding wheel with different geometric parameters.The wear depth of microstructure unfolding wheel with different geometric parameters is calculated within 0.2s.Taking the minimum wear depth and the maximum friction coefficient as the optimization targets,the optimization models of the microstructure on the unfolding wheel are established.The multi-objective optimization problem is solved and analyzed,and the parameter optimization model based on NSGA-II algorithm is solved by MATLAB software.The optimal geometry parameter matching of the microstructure surface of the unfolding wheel is obtained in the feasible region.Finally,the contact model of steel ball and microstructure unfolding wheel is simplified,and an experimental bench is designed and built.The microstructure test piece is designed and processed according to the orthogonal test,and the point contact dry friction and wear test is performed.The comparison of the wear test and numerical simulation results verifies the accuracy of the numerical simulation of the wear of the unfolding wheel,and ensures the rationality of establishing the optimization model of the geometric parameters of the microstructure surface of the unfolding wheel based on numerical simulation and the correctness of the best parameter matching.In this thesis,theoretical analysis,numerical simulation and physical experiment are combined to study the optimal geometric parameter matching of the microstructure surface of the unfolding wheel,which provides a theoretical basis for the application of the microstructure unfolding wheel to the automatic surface quality inspection of steel balls.