行星滚柱丝杠螺纹副动载荷分布计算方法研究

Study on calculation method for dynamic load distribution of thread pair of planetary roller screw mechanism

为揭示行星滚柱丝杠在高速运转条件下的动载荷分布特性,基于螺旋曲面方程和变形协调关系,提出了滚柱-丝杠及滚柱-螺母螺纹在接触点处静态接触力计算方法,推导出承载后接触角计算公式。在此基础上,进一步考虑高速运转产生的惯性力作用,建立了行星滚柱丝杠螺纹牙动载荷分布模型。通过与行星滚柱丝杠有限元接触模型进行对比,两者误差在5%以内,验证了所建理论模型的正确性。分析了丝杠转速、轴向载荷、螺距及牙侧角等参数对动载荷分布的影响规律。结果表明:惯性力使滚柱产生靠近螺母远离丝杠的趋势,使得滚柱-丝杠侧动态接触力减小,滚柱-螺母侧动态接触力增大;动载荷分布不均程度与丝杠转速和螺距呈正相关,与牙侧角呈负相关,且轴向载荷大小对动载荷分布影响较大。

To reveal the dynamic load distribution characteristics of planetary roller screw mechanism under the high-speed operating conditions,based on the spiral surface equation and deformation coordination relationship,a static contact force calculation method of the roller-screw and roller-nut thread at the contact point is proposed,and a formula for calculating the contact angle after bearing is derived.On this basis,further considering the inertial force generated by using high-speed operation,a dynamic load distribution model for planetary roller screw mechanism thread was established.By comparing with the finite element contact model of planetary roller screw mechansim,the error is below 5%,which verifies the correctness of the model established.Finally,the influence of the parameters such as screw speed,axial load,pitch,and tooth flank angle on the distribution of dynamic load was analyzed.The results show that the inertia force causes the roller to have a tendency to move closer to the nut and away from the screw resulting in a decrease in dynamic contact force on the roller screw side and an increase in dynamic contact force on the roller nut side.The degree of uneven distribution of dynamic load is positively correlated with the screw speed and pitch,and negatively correlated with the tooth side angle.The size of axial load has a significant impact on the distribution of dynamic load.