| 摘要 |
PROBLEM TO BE SOLVED: To provide a motion device inexpensively assemblable with high working efficiency while preventing rolling elements from falling. SOLUTION: A ball-spline device S includes a spline shaft 1 having a ball rolling surface 10 and an outer tube 2 which has a plurality of balls 3, enables the balls 3 to roll on the ball rolling surface 10 while applying a load to each ball 3, and moves along the spline shaft 1 at a predetermined distance Y from the ball rolling surface 10. The spline shaft 1 includes, at least one end, a ball introduction surface 10' which is separated from the outer tube 2 a distance M which is larger than the predetermined distance Y and smaller than the radius of the ball 3. Consequently, the balls 3 are prevented from radially projecting out of the outer tube 2 and falling off the outer tube 2 during the assembling. COPYRIGHT: (C)2009,JPO&INPIT
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