Dynamics Performance Analysis Of Ball Screw And Optimization Of Returnner

The ball screw has high efficiency and high precision,and is widely used in aerospace,CNC machine feed systems and other fields.As the core functional component of CNC machine tools,the ball screw is gradually improving its requirements,and its performance requirements such as bearing capacity and vibration noise are getting higher and higher.In order to improve the performance of ball screw by-products in China,this paper takes the inner-circulating ball screw as the research object,analyzes the variation law of the friction torque of the ball screw,and optimizes the return curve of the returner.The main research contents of this paper are as follows:(1)According to the contact characteristics of the ball and screw spiral raceway and the principle of tribology,the source of the friction torque of the ball screw is analyzed.The theoretical analysis model of the friction torque of the ball screw is established.The screw is obtained by solving the model by example.The influence of the rotational speed on the friction torque is small,and the axial load has a significant influence on the friction torque,showing a linear relationship.The factors affecting the frictional torque of the ball screw are analyzed.(2)The dynamic simulation model of the inner circulation ball screw is established.After the ADAMS simulation analysis,the influence of the screw speed on the friction torque is not obvious;the axial load has a great influence on the friction torque,which is linear.The rationality of the theoretical model is shown.The simulation results show that the return motion of the parabolic curve of the fifth-order parabola is more stable than that of the cubic parabolic curve.The maximum impact occurs when the ball enters and exits the return.The experimental platform of frictional torque detection of ball screw is built.The variation of friction torque under different speed and load conditions is measured.The results are in good agreement with the theoretical model and simulation results.The correctness of the theoretical model and simulation results is verified.(3)A curve of the bead based on the cubic NURBS method is designed.Different ball-return curves were obtained by changing the coordinate values of the control vertices on the NURBS curve,and they were simulated and analyzed.The BP neural network was used to fit the relationship between the control points and the maximum friction torque.Taking the friction torque as the optimization target,the particle swarm optimization algorithm was used to optimize the calculation,and the optimal one bead curve was obtained.The correctness of the friction torque generated by the optimized back-bead curve is verified by simulation analysis.The results show that for the optimized bead curve,the frictional torque generated by the ball on the returning device when entering and exiting the returning channel is small,and the performance of the ball screw is improved.