| 摘要 |
A cheap and small ball spline bearing comprises: identical balls; an outer hollow cylinder; a cylindrical holding apparatus fixed to the inner peripheral surface of this cylinder; and a spline axis. In the outer cylinder, three projections are formed in the inner peripheral surface at regular intervals in the axial direction, track grooves adapted to load the balls are formed in both side surfaces of each projection, and U-shaped grooves between the projections are formed to have the almost same depth. In the holding apparatus, infinite circulating passages for the balls using the both side surfaces as track grooves are formed symmetrically on the right and left sides with regard to the central line in the axial direction of each U-shaped groove, and windows each width of which is slightly narrower than the ball diameter are formed in the axial direction at the locations of the track grooves. The spline axis has six protuberances formed so as to sandwich the load balls existing at the locations of the projections of the cylinder, and track grooves are formed in the portions which are in contact with the balls. This bearing has a high rigidity and a small slide resistance and can be easily and accurately worked.
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