Analysis Of Subsurface Stress Influence Characteristics Of Microstructure Unfolding Wheel And Parameter Optimization Design

The unfolding wheel is the core component of the surface quality inspection device for bearing steel balls.Steel balls are prone to slippage during the inspection process.Detection accuracy is reduced.And the unfolding wheels are prone to failure due to wear and tear.Therefore,microstructures are machined on the surface of the unfolding wheel to increase the coefficient of friction between the balls and the unfolding wheel and to reduce the amount of wear.Changes in subsurface stresses on microstructured unfolding wheels are the main factor influencing wear and fatigue damage of unfolding wheels.Therefore this paper investigates the subsurface stresses of microstructure unfolding rounds with different geometrical parameters.The influence characteristics of different microstructures on the subsurface stress of the unfolding wheel were analyzed.And the geometric parameters of the microstructure unfolding wheel have been optimized.The motion and contact characteristics of the unfolding wheel and the steel ball are analysed.The contact area and contact stress between the unfolding wheel and the steel ball are calculated by Hertz theory.Then subsurface stresses and subsurface stress distributions are calculated from the calculated contact stresses and contact surfaces.Finally,according to the subsurface stress concentration generated by the microstructure,the correlation between the geometric parameters of the microstructure unfolding wheel and the fatigue resistance performance was analyzed.And the correlation between subsurface stress concentration and fatigue life is also analysed.Different microstructural geometric parameters(shape,area,spacing and arrangement)are numerically simulated.And friction,wear and fatigue tests are designed.Firstly,the single-variable method is used to analyze the influence characteristics of different microstructural geometric parameters on the surface stress of the unfolding wheel.Then,orthogonal experiments are designed for microstructural geometric parameters and an experimental bench is built.The coefficient of friction and the amount of wear of different microstructure parameters are measured.And the fatigue failure morphology of the microstructure on the surface of the unfolding wheel was observed.Finally,ABAQUS numerical simulation and wear model are used to analyze the wear depth of the microstructure unfolding wheel.Based on the above obtained friction data,wear data and subsurface stresses,the model is carried out.The objective function for the optimal design of the microstructure unfolding wheel is established.The DNSGA-II dynamic multiobjective optimization algorithm is used to obtain the local optimal solution.The TOPSIS superior solution distance method was used to rank the individuals in the optimal solution of microstructure parameters obtained by DNSGA-II.The most suitable coefficient of friction and wear and subsurface stresses were selected for the microstructural parameters.Desired frictional wear properties and fatigue resistance are obtained.Optimal geometry of the microstructure increases the coefficient of friction of the unfolding wheel.The amount of wear on the unfolding wheel is reduced.And the fatigue resistance of the microstructure has been improved.The basic theory of unfolding wheels was improved.