| 摘要 |
<p>PURPOSE:To decrease backlash, etc., by freely movably supporting a block which prohibits the rotation of a turn table in the direction nonparallel with a receiving surface and nonparallel with the center line of rotation of the turn table. CONSTITUTION:The rotating position of the turn table 32 is determined by the contact position of an outer race 41 on the receiving surface 44 provided on the block 45 at all times. The receiving surface 4 of the block 45 prohibits the counterclockwise rotation of the table 32 via an outer race 41. The direction where the surface 44 extends is nonparallel from the moving direction of the nut 47 of a ball screw 46, and therefore, the table 32 rotates counterclockwise to some extent and stops when the nut 47 is moved upward to a specified extent by driving a motor 52 in one direction. Conversely, the table 32 rotates clockwise and stops when the nut 47 is moved downward by driving the motor 52 in the other direction. The rotation of the nut 47 and the table 47 is not one to one and is determined by the angle between the direction where the surface 44 extends and the direction where the nut 47 moves linearly. The speed reduction ratio is higher as the angle is smaller. The speed is reduced by a wedge effect.</p> |
