考虑位置度误差的RV减速器多组滚针轴承动态载荷特性研究

A Study on Dynamic Load Characteristics of Multi-group Needle Roller Bearings Used in RV Reducer Considering the Position Errors

滚针轴承是制约RV减速器工作可靠性及其使用寿命的关键部件,为有效地揭示位置度误差对滚针轴承动态接触载荷变化及多组滚针轴承传力均载性能的影响规律,提出含位置度误差的多组滚针轴承-摆线针轮耦合传动机构动力学模型。该方法通过开展摆线针轮多点啮合接触分析,计算摆线针齿副法向接触载荷和切向摩擦载荷;通过开展滚针轴承动态接触分析,计算滚动体接触载荷及轴承转动副等效约束反力。在此基础上,提出摆线轮滚针轴承孔位置度误差表达方法,完成多组滚针轴承-摆线针轮耦合传动机构动力学模型组集。最后,以典型三曲轴RV80E减速器为对象,分析位置度误差对滚针轴承动态载荷分布规律及多组轴承传力均载特性的影响。研究表明,轴承滚动体接触载荷最大峰值可达其平均值的5.19倍,轴承载荷最大值和最小值分别是其平均值的1.60倍和0.21倍,载荷波动幅值差很大;随着位置度误差范围的放大,加工精度等级的降低,滚针轴承载荷平均值偏差增大,轴承之间偏载问题越突出。

The needle roller bearing(NRB) is a critical part that restricts the operational reliability and service life of RV reducers.The research aims to reveal the influences of position errors on the changes in the dynamic contact load acting on an NRB and on the force-transfer and loading-sharing performance of multiple sets of NRBs. For this purpose, a dynamical model of a transmission mechanism coupling multiple sets of NRBs and cycloidal-pin gears considering position errors is established. Therein, by analyzing multi-point meshing and contact patterns in a cycloid-pin gear mechanism, the normal contact load and tangential friction load of the cycloid-pin gear pair are calculated. In addition, the contact load of rolling elements and the equivalent constraining force on the bearing joint are obtained by analyzing the dynamic contact of NRBs. On this basis, the expression for the position errors of the bearing holes on the cycloidal gears is proposed, and the integration of dynamical model for the transmission mechanism coupling multi-group of NRBs and cycloidal-pin gears is completed. Finally, taking a typical RV80E reducer with three crankshafts as the research object, influences of position errors on the dynamic load distribution on NRBs and on the force-transfer and load-sharing performance of multiple sets of bearings are investigated. Research results indicate that the maximum load on rolling pins in the NRB can be as high as 5.19 times the average load, and the maximum and minimum loads on the bearings are separately 1.60 and 0.21times the average, indicative of a large amplitude difference in load fluctuation. With increases in the range of the position errors and the reduction in machining precision, the difference in the average load on the NRBs increases and the deflection-induced load between bearings increases.