| 摘要 |
<p>A ball screw in which surface hardness of balls is higher than both of surface hardness of a ball screw groove of a screw shaft and surface hardness of a ball screw groove of a nut, and a solid lubricant film is formed on a surface of the balls with a thickness of 1 µm or more and 5 µm or less. Further, cross-sectional shape of grooves 11 and 21 of a screw shaft 1 and a nut 2 is a Gothic arc. A ratio (R/D) of a radius (R) of the arcuate cross-section of the groove 11 with respect to diameter (D) of balls 2 is set to 51.0% or more and 52.0% or less. The solid lubricant film made of MoS 2 is formed on the surface of the balls 3 with a thickness of 0.5 µm and 3.0 µm or less.</p> |
