A comprehensive analysis method of the performance degradation of planetary roller screws under the time-varying load and errors

Time-varying loads, manufacturing errors, and assembly errors are the main factors leading to the performance degradation of the planetary roller screw mechanism. This paper proposes a comprehensive analysis method for the performance degradation of the planetary roller screw mechanism caused by time-varying loads and manufacturing and assembly errors. Firstly, a simulation analysis model of the planetary roller screw mechanism was established and its effectiveness was verified. A quantitative analysis was conducted on the influence of manufacturing and assembly errors on the load distribution, revealing the load-bearing mechanism under the influence of errors. Secondly, loading experiments were conducted on the planetary roller screw mechanism, and the degradation of its load-bearing performance was divided into the normal degradation stage, the accelerated degradation stage, and the failure stage. The experimental results prove that the initial transmission accuracy has a significant impact on the degradation of the load-bearing performance, determining the occurrence of the node where the accelerated degradation stage appears in the load-bearing performance. Thirdly, the wear status of the threads and gears was examined, and the results showed that material peeling was the main factor causing the degradation of load-bearing performance.