Abstract:

Taking an inverted planetary roller screw as the research object, the kinematic models were developed to investigate axial displacement and slip velocity of the roller relative to the screw, which was caused by a pitch circle mismatch between the roller thread and the roller gear. First, the calculation formulas of the angle of slip, axial displacement and slip velocity of the roller relative to the screw were presented, and the effects of roller displacement on the overall lead and slip velocity of the mechanism were analyzed. Then, an inverted planetary roller screw was selected as an example, and the pitch circle mismatch values due to contact deformation were derived. Furthermore, the axial displacement and slip velocity of the roller relative to the screw were calculated by using the formulas respectively. The results show that the roller displacement does not affect the lead of the overall system, the slip must occur at the nut-roller interface, and slip velocity is decreased by decreasing the pitch mismatch values at the screw-roller interface effectively.

Key words: inverted planetary roller screw, pitch circle mismatch, axial displacement, slip velocity

摘要：

以反向式行星滚柱丝杠副为研究对象,对因滚柱螺纹节圆与滚柱齿节圆产生偏移而导致的滚柱和丝杠发生相对滑动和相对轴向位移的问题进行了研究。首先建立了滑动角、滚柱相对丝杠轴向位移和各部件相对滑动速度运动学分析的模型,着重分析了滚柱位移对整个机构导程和滑动速度的影响;再以某一反向式行星滚柱丝杠副为例,计算了由接触变形引起的节圆偏移量,并采用该模型分别计算了滚柱相对丝杠的轴向位移和滑动速度。研究结果表明：滚柱轴向位移不会影响系统导程;螺母-滚柱侧必然存在轴向滑动;减小节圆偏移量能有效降低丝杠-滚柱侧滑动速度。

关键词: 反向式行星滚柱丝杠副, 节圆偏移, 轴向位移, 滑动速度