| 摘要 |
<p>PURPOSE:To prevent seizure and abrasion in high speed rotation by releasing a ball from two-point contact with a ball holding and penetrating part at the time of cutting off of overload and by bring it into a rolling contact between both a driven and a pressure plates so as to lighten phase adjustment for restoring engagement. CONSTITUTION:When overload is applied to a driven plate 17, even though rotation of the plate 17 is stopped, an axis A keeps on rotating and a ball 15 is moved to the right direction guided by a root part 14a against a component of a force P, gets out of a ball holding bottom part 18 and moves to a flat 19. This movement is generated by that the ball 15 climbs up from the bottom part 18 to a boundary 18a of the flat part 19 and moves in the axial direction by the length L. In this way, the ball 15 climbs up a slope 19b of a step part 19a. At this time, as an inclination angle phi of the slope 19b is larger than an inclination angle theta of a pressure plate 30, the ball 15 is moved in the same direction by H receiving a component of a force in the radial direction to the outside, released from the contact of a strong wedge action pressed at two points to a notch 14 and freely rotated and held by the plate 30, the flat part 19 and the step part 19a.</p> |
