| 摘要 |
PROBLEM TO BE SOLVED: To provide a ball screw being easy to manufacture while reducing vibration caused by the passage of balls. SOLUTION: The ball screw includes a threaded shaft 1 having on its outer peripheral surface a helical thread groove 1a; a nut 2 having on its inner peripheral surface a thread groove 2a opposite to the thread groove 1a of the threaded shaft 1 and engaged with the threaded shaft 1 via a number of balls 3 rollably loaded into a helical ball rolling path 5 formed by both thread grooves 1a and 2a; and a return tube 6 secured to the nut 2 for scooping up the balls 3 at one end A of the ball rolling path 5 to feed the balls to the other end. At a portion E1 near the one end A of the ball rolling path 5, the lead angle of the thread groove 2a on the nut 2 is gradually varied so that preloads decrease toward the one end A of the ball rolling path 5. The preloads are eliminated at a portion B in front of the one end A of the ball rolling path 5. COPYRIGHT: (C)2003,JPO
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