| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw capable of increasing load capacities to a thrust load, and multidirectional radial load and moment load.SOLUTION: A ball screw increases a screw shaft 2 having a spiral screw shaft-side spiral groove 2a on its outer peripheral face, a nut 4 having a spiral nut-side spiral groove 4a opposed to the screw shaft-side spiral groove 2a, on its inner peripheral face, and movable along the screw shaft, and a plurality of balls 6 disposed between the screw shaft 2 and the nut 4. The screw shaft-side spiral groove 2a and the nut-side spiral groove 4a form load rolling passages 8 of three or more rows on which the balls 6 are rolled, and an outer contact angle θout between the nut-side spiral groove 4aout forming the outer load rolling passage 8out and the ball 6 is smaller than an inner contact angle θoutin between the nut-side spiral groove 4ain forming the inner load rolling passage 8in and the ball 6.SELECTED DRAWING: Figure 2 |
