双层滚动轴承转速分配比

Speed Distribution Ratio of Double-Decker Rolling-Element Bearings

针对双层滚动轴承,分别采用纯滚动理论和摩擦力矩理论推导出转速分配比的理论计算公式,并对不同结构和不同润滑方式下的转速分配比进行了试验研究。研究结果表明:根据摩擦力矩理论计算得到的转速分配比比根据纯滚动理论计算得到的转速分配比更接近于试验测得的结果。双层滚动轴承的转速分配比与内、外层轴承的节径比有关,节径比越大,转速分配比越好。当工作转速为10000r/min时:节径比为0.59时,转速分配比为0.038;节径比为0.75时,转速分配比可达0.17。转速分配比还与内、外层轴承的润滑方式和润滑粘度有关,内、外层轴承都采用油润滑比都采用脂润滑得到的转速分配比更加稳定。

The speed distribution ratio formulas of double-decker ball bearings （DDBB） are respectively derived based on pure rolling theory and friction torque theory. And then the speed distribution ratio for different structures and lubricating methods are experimentally studied. The results show that the ratio calculated using friction torque theory is closer to the experimental results. The speed distribution ratio is mainly determined by the pitch diameter ratio of the inner and outer bearings. Better speed distribution ratio performance can be obtained from bigger pitch diameter ratio. When the rotor rotates at the speed of 10 000 r/rain, the speed distribution ratio equals 0. 038 for relatively smaller pitch diameter ratio 0.59, while the distribution ratio becomes 0. 17 for larger pitch diameter ratio 0.75. The speed distribution is also influenced by lubricating methods and lubricant viscosity. Adopting oil to lubricate both inner and outer bearings is more stably than grease lubrication.