考虑径向载荷的行星滚柱丝杠副弹塑性接触及精度损失分析

Analysis of Elasto-plastic Contact and Accuracy Loss of Planetary Roller Screw Pair Considering Radial Load

行星滚柱丝杠副在短时高过载下发生弹塑性变形,易降低传动精度和增大摩擦力矩,影响其使用寿命;其径向载荷和节距偏差亦对螺纹上的接触载荷影响较大。因此,建立了行星滚柱丝杠弹塑性接触和精度损失的计算模型,利用有限元方法计算残余塑性变形,分析了径向载荷、节距偏差、螺纹牙数、接触角以及螺纹升角对残余塑性变形的影响。结果表明,残余塑性变形随螺纹牙数、螺纹升角增加而减少,随接触角的增加而增加;接触角取36°~40°、螺纹升角取1°~5°时,能够得到较小的精度损失;增加轴向载荷会加剧行星滚柱丝杠副的精度损失,而径向载荷在一定程度上对减少精度损失有益,但会加剧塑性变形在滚柱间的分布不均。

The elasto-plastic deformation of planetary roller screw pair under short-term high overload will reduce the transmission accuracy and increase the friction torque,which will affect the service life.More⁃over,the radial load and pitch error have immense influence on the contact load of all threads.Therefore,the calculation model of elasto-plastic contact and accuracy loss of planetary roller screw pair is established.The re⁃sidual plastic deformation is calculated by the finite element method.The effects of radial load,pitch error,thread number,contact angle and helix angle on the residual plastic deformation are analyzed.The residual plastic deformation decreases with the increase of thread number and thread rising angle,and increases with the increase of contact angle.When the contact angle is 36°~40°and helix angle is 1°~5°,the accuracy loss is small.The increment of axial load aggravates the accuracy loss of planetary roller screw pair.Although the radial load is beneficial to reduce the accuracy loss,it will aggravate the uneven distribution of plastic deformation be⁃tween rollers.