| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a ball screw that achieves superior sealing performance of a sealing member, and easy fitting of the sealing member onto the outer periphery of a ball screw shaft from an end in the axial direction. <P>SOLUTION: The seal member 5 has an elasticity which satisfies Lb>Ls before fitted onto the outer periphery of the ball screw shaft 1 and Lb≤Ls when fitted onto the outer periphery of the ball screw shaft 1, where Lb is the maximum outer peripheral length of the ball screw shaft 1 during the fitting of the seal member 5, and Ls is the inner peripheral length of the inner top part of a seal lip 11. Accordingly, the seal member 5 is easy to be fitted onto the outer periphery of the ball screw shaft 1 from the end in the axial direction, and has superior sealing performance because a slit need not to be provided in the seal member 5. When the outer peripheral surface of the ball screw shaft 1 has an incomplete thread portion 9 of a male ball screw groove 3, a chamfer 15 is formed on the incomplete thread portion 9. Thus, the seal lip 11 is hard to be damaged when the seal member 5 is fitted from the end in the axial direction of the ball screw shaft 1. <P>COPYRIGHT: (C)2013,JPO&INPIT |
