| 摘要 |
PURPOSE:To reduce cost and size by arranging a ball between a ringged flat region which is orthogonalized with the rotational center of a first member and a cam surface forming region of a second member, and by providing a means for energizing the second member against the first member in the direction of the rotational center. CONSTITUTION:When a load on following side is of no more than a preset level, the point of a partition wall 4a of a member 4 on following side is put on a ringged flat surface 2b of a member on driving side, while a disc spring 14 is in a certain condition. Through the rotation of the member on driving side in a direction C, a ball 6 is energized by a plate spring 8 in the direction C, and is in a locked condition, while the driving force is transmitted to the member 4 on following side. When the member on driving side is rotated in a direction C', regardless of the energizing effect of the plate spring 8, the ball 6 is slid to the member on driving side, or to the member 4 on following side, and is thus in a free condition. When a load on following side exceeds a certain level, while the member on driving side is rotated in the direction C, the member 4 on following side is not rotated in the direction C, but is moved in the direction of a rotational center, and the disc spring 14 is deformed thereby, while the point of the partition wall 4 or the member 4 or following side is separated from the ringged flat surface 2b or the member on driving side, and a torque limit function is thus achieved. |
