| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw with a large lead hardly causing a breakage or noise even in the use with high-speed feed or high-speed rotation. SOLUTION: This ball screw 1 comprises a screw shaft 2 having a spiral groove 2a on the outside surface; a nut 3 having a groove 3a opposed to the groove 2a of the screw shaft 2 on the inside surface and screwed to the screw shaft 2 through a number of balls 4 rollingly loaded on a spiral ball rolling passage 6 formed between both the grooves 2a and 3a; and a return tube 7 for scooping up the ball 4 at one end P of the rolling passage 6 and sending it to the other end. The end part 7a of the return tube 7 is connected to tone end P of the passage 6 so that the difference in levelΔt between the contact part with the ball 4 of the groove 3a of the nut and the inner surface 7b of the end part 7a of the return tube 7 is 0.2 mm or less, and the rolling directional angle change of the ball 4 caused by the scooping of the ball 4 from the passage 6 to 10 deg. or less. |
