关键词: 行星滚柱丝杠机构, 公差匹配, 加工误差, 行程精度, 轴向间隙

Abstract: The active design of PRSM tolerance was essential to improve the transmission performance and processing feasibility. A PRSM travel error and axial clearance model was established by integrating the thread coaxiality errors, pitch errors and mid-diameter errors of the screw, roller and nut, and the sensitivity index of each error factors was calculated. Based on the expert judgment hierarchical analysis method of triangular fuzzy number, processing weights, and initially assigning the tolerance of each error terms of PRSM travel accuracy were calculated. The tolerances of each error terms of axial clearance tolerances were optimized based on the sequential quadratic programming algorithm. And the effectiveness of the method was verified by taking the standard PRSM as an example. The results show that the method of optimizing the tolerances of each error terms for the stroke accuracy and axial clearance balances the stroke accuracy and axial clearance extremely well, and relaxes the width of the key tolerance zones, which improves the machining feasibility of the parts. The example shows that after optimization, the minimum value of axial clearance in the complete cycle is changed from -25 μm to 0 to avoid thread interference; after optimization, the amount of V300 stroke variation is basically unchanged, and the width of tolerance zone is increased by 65% on average, which ensures PRSM grade 5 accuracy index, improves the machining feasibility of key parts, reduces machining costs and may provide reference for PRSM tolerance active design theory.

Key words:  , planetary roller screw mechanism(PRSM), tolerance matching, machining error, itinerary accuracy, axial clearance