考虑误差的行星滚柱丝杠副滚柱承载分布

Load distribution of rollers considering errors in planetary roller screw mechanism

为改善滚柱螺纹牙承载分布,在丝杠受轴向拉力和螺母受轴向压力作用下,基于滚柱两接触侧变形协调关系,建立考虑误差的滚柱螺纹牙承载分布计算模型.将计算的滚柱各螺纹牙承载比与直接刚度法计算结果进行对比,验证了模型的正确性.系统分析负载、接触角、螺旋升角、滚柱螺纹牙数和螺纹副材料弹性模量比对滚柱承载分布规律的影响.结果表明:在相同误差分布下,负载越小,滚柱螺纹牙承载分布波动越大,负误差更有利于降低前3个螺纹牙承载比例;接触角或螺旋升角越小,滚柱螺纹牙承载分布越均匀;随着螺纹牙数增大,各螺纹牙承载比例逐渐降低,且误差对承载比的影响变小;降低丝杠或螺母弹性模量可有效改善滚柱螺纹牙承载分布.

To improve the load distribution of rollers thread, based on the relationship of deformation compatibility on two contact sides of the roller,a model of load distribution of the roller thread considering errors is established when the screw shaft withstands tension and the nut withstands compression. The load ratios among the roller thread teeth are compared with the results of direct stiffness method to verify the correctness of the presented method. Then the factors,such as load,contact angle,helix angle,number teeth of the roller thread and material Young＇s modulus ratio,which affect the load distribution of the roller thread are systematically studied. The results show that the smaller the load,the larger the fluctuation of load distribution on teeth of the roller thread. The negative errors are able to decrease load ratios of the fore 3 teeth of the roller thread. The load distribution is more even by decreasing the contact angle or helix angle.Increasing the number teeth leads to the decrease of the load ratios and the influence of error on load ratios.Besides,it is helpful to improve load distribution of roller thread by decreasing the Young ＇s modulus of the screw or the nut.