行星滚柱丝杠副摩擦力矩及传动效率研究

The frictional moment and transmission efficiency of planetary roller screw

摘要:

以行星滚柱丝杠副为研究对象,基于赫兹接触理论和等效球的方法,分别计算了由材料弹性滞后、滚柱自旋滑动和润滑油粘滞阻力所产生的摩擦力矩,分析了接触角、螺旋升角和滚柱牙数对摩擦力矩的影响规律．在此基础上,建立了行星滚柱丝杠副传动效率计算模型,研究了丝杠转速和上述结构参数与传动效率的关系．结果表明,引起摩擦力矩的主要原因是滚柱的自旋滑动;丝杠转速增加导致传动效率呈递减趋势,相同丝杠转速下,较大的轴向载荷能获得较高的传动效率;较大的接触角能够减小摩擦力矩和提高传动效率;螺旋升角对摩擦力矩的影响很小,但能提高传动效率;增加螺纹牙数有利于提高承载能力,并降低总摩擦力矩．

Abstract:

The frictional moments are calculated respectively based on the Hertzian contact theory and the method of effective ball considering elastic hysteresis of material, spinning sliding of roller and viscosity of lubricating oil, and the influences of contact angle, helix angle and tooth number of roller thread on frictional moment are analyzed. Furthermore, a calculating model of transmission efficiency for planetary roller screw is developed and the relationships of between the screw rotational speed, structure parameters mentioned above and transmission efficiency are discussed. The results show that the frictional moment is principally generated by roller's spinning sliding. Increasing the rotational speed of screw leads to decreasing of the transmission efficiency and a higher axial load can increase the transmission efficiency at the same rotational speed of screw. A higher contact angle can decrease the frictional moment and increase the transmission efficiency. The helix angle has less influence on frictional moment and can improve the transmission efficiency. Besides, it is helpful to enhance the carrying capacity and reduce the total frictional moment by increasing the tooth number of the roller thread.