摘要 |
There is a track groove of a ball bearing for a rectilinear motion comprising a track member, a slide member arranged to sandwich the track member and adapted to be rectilinearly slidable along the track member, track grooves formed in both side portions of the track member and of the slide members so as to face one another, and a number of balls rotatably inserted between the track grooves which face each other. The contact portion of the track groove with the ball is formed by two or more kinds of arcs having different radii. The ball comes into contact with a single arc under a light load and with a plurality of arcs under a heavy load. The radius of the arc near the contact center with the ball may be slightly larger than the radius of the ball and the other arcs may be larger than the central arc. Or, the large arc may be formed at a location near the contact center with the ball and the arcs smaller than this central arc may be formed at locations other than the contact center. The slide resistance of the bearing can be reduced with this simple constitution of the track groove consisting of a plurality of arcs. |