A Study on Waving Amplitude Suppression of Linear Motion Ball Guide

Previous work has clarified that the waving amplitude of a linear motion ball guide (LMBG) can be reduced by optimizing for the shape of crowning on each end of raceways in a carriage. Waving in a table using LMBG becomes in 1/100 μm order amplitude by the optimization; it is in 1/10 μm order without the optimization. Moreover, the waving analysis method considering table deformation and misalignment of assembly has also been developed. In recent years, waving has been required in 1/1000 μm order. However, it is analytically confirmed that only crowning configuration optimization does not achieve this request. Considering the principle of waving generation, increasing balls in LMBG is the most effective to suppress the waving. Although balls should become small not to change the carriage length and to increase balls, balls becoming smaller degrades the load capacity of LMBG. Balls should be drastically increased further to keep capacity and suppress waving. For the problem, a new LMBG design with the number of raceways to eight by double-rowing has been led; ordinary LMBG has four raceways. This paper reports the development process and evaluation results of the LMBG with the new design, although the product has already been launched.