Research On The Friction Characteristics And Influence Of Precision Ball Screw Pair Under High Frequency And High Load Condition

Precision ball screw pairs are one of the important transmission and actuator components of linear actuators.Under the high-frequency and high-load conditions of aerospace,the precision ball screw pair lacks good lubrication and heat dissipation,and the deterioration of the friction state will seriously affect its performance,and the jam failure will occur when it is serious.Therefore,it is necessary to study the friction characteristics and influence of precision ball screw pairs under high-frequency and high-load conditions,understand the influencing factors and change laws of the friction characteristics of ball screw pairs,and improve the performance and reliability of ball screw pairs under aerospace conditions.Based on hertz contact theory and the curved surface equation of the raceway space,the contact characteristic analysis model is established by considering the contact state after plastic deformation,thermal deformation and deformation coordination,and the auxiliary dynamic equation of the ball lead screw during the variable speed movement of the inertia load and the comprehensive friction coefficient is derived.Then,based on the contact characteristic analysis model and dynamic equation,the friction model such as the paraelastic hysteresis friction and the viscous friction of the grease of the ball screw was established,and the theoretical contact angle under high-frequency high load conditions and temperature rise conditions was solved by using the fixed-point iterative method,the change law of the contact angle was analyzed,the influence of frequency,displacement amplitude and load on the positive pressure and contact deformation of the contact point was solved,and the influence of frequency,displacement amplitude,load and temperature rise on the total friction moment of the lead screw was studied.The structural parameters of the lead screw pair are optimized with the goal of reducing the contact force and friction moment.On this basis,through the analysis of the heat generation and convective heat transfer coefficient of the ball screw sub-heat source,the influence of thermal deformation on the structural parameters is discussed,the working temperature of the lead screw pair is derived,and the simulation analysis results of the ball screw sub-temperature rise are compared,and the thermodynamic coupling simulation analysis of the lead screw pair is carried out on this basis.By studying the relationship between load,displacement amplitude,frequency and temperature rise and lead screw efficiency and wear,the influence of these parameters on lead screw efficiency and wear per unit time is obtained.Finally,the paper designed and built a lead screw sub-temperature rise and efficiency test bench,conducted temperature rise and efficiency test under high-frequency and high load conditions,measured the temperature rise and efficiency of the ball screw pair under different frequencies,displacement amplitudes and load conditions,and basically verified the results of theoretical analysis.