| 摘要 |
PURPOSE:To make precise machining of helical groove of the ball nut with large lead possible by providing buffer groove at the center of the inner surface of the helical groove of the ball nut. CONSTITUTION:The grindstone 7 which grinds the helical groove 3 in the ball nut 2 is usually held by the quill 8 which is tilted for lead agnle of the screw. To machine the helical groove 3 of the ball nut 2, at first, the helical groove 3 is ground down to the center part of the ball nut 2, and then, the ball nut 2 is turned by 180 deg. around the point P and the rest of the groove 4 is ground down to the center part. At this time, the buffer groove part 5 forms the flank for the grindstone 7 at the center part of the ball nut, and the grindstone 7 in grinding can be prevented from getting out of shape. |
