| 摘要 |
PURPOSE: To improve the efficiency of motive power transmission by installing plural inside recessed parts having an inside meshing part on the outer periphery surface of an inner ring and plural outside recessed parts having a roller key storing part and outside meshing part on the inner periphery surface of an outer ring and energizing the roller key onto the inside recessed part side by a spring. CONSTITUTION: When an inner ring 161 is rotated in the direction meshing the inside meshing part 27 of an inside recessed part 25 with a roller key 18 by a starter at the engine start time, the roller key 18 is held between the inside meshing part 27 and the outside meshing part 31 of the outside recessed part 26 in the case below a set number of revolution determined by the spring force of a spring 191 and the motive power is transmitted between the inner ring 161 and the outer ring 171 . In this case, the meshing parts 27, 31 come in surface contact with the outer surface of nearly 1/4 circumference of the roller key 18 and the load of the contact surface is comparatively small and the motive power transmission direction is the tangential direction of an imaginary circle C1 M and excellent motive power transmission efficiency is obtained. When the number of revolution of the ring 171 exceeds that of the ring 161 at the engine running start, the roller key 18 is stored in the storing part 29 of the outside recessed part 26 against the spring 191 and the motive power transmission is intercepted. |
