内曲线径向柱塞马达滚柱-柱塞配合间隙优化

Optimization of roller-piston fitting clearance of cam lobe radial-piston motor

针对内曲线径向柱塞马达的泄漏和磨损问题,在考虑黏压效应、空化效应、油液压缩性及油沟压力与油膜边界压力的耦合作用下,对滚柱-柱塞摩擦副之间的动静压混合润滑油膜建立非稳态的弹流润滑仿真模型.基于该模型,对比分析了不同的配合间隙尺寸对油膜特性及泄漏的影响.结果表明:减小配合间隙可以降低空化、减小泄漏、提高油沟的静压支撑作用,增加配合间隙则可以提高油膜的动压效应.综合考虑最小油膜厚度、泄漏量和空化三个因素,滚柱-柱塞配合间隙的最优值为0.03 mm.

To solve the problem of the leakage and wear of the cam lobe radial-piston motor, an unsteady elastohydrodynamic lubrication model was proposed for the hydrostatic-dynamic hybrid lubrication between the roller and the piston. In this model,the viscosity-pressure effect, cavitation effect, oil compressibility, coupling effect of lubricating groove pressure and oil film boundary pressure were considered. The impact of different fitting clearance sizes on the oil film characteristics and leakage was analyzed based on the proposed model.Finally,the results indicate that cavitation is weakened,leakage is reduced,and the static pressure supporting effect of the lubricating groove is enhanced, with the decrease of fitting clearance. However, as fitting clearance increase, the dynamic pressure effect of the film is improved. When the three factors of minimum oil film thickness,leakage,and cavitation are considered,the optimum value of roller-piston fitting clearance is 0.03 mm.