| 摘要 |
A rotation transmission device is provided which has a minimum play in the rotational direction, which is reliable by preventing the rollers from erroneously engaging during idling, and which has high torque capacity. A control retainer 19A and a rotary retainer 19B are mounted between an outer race 11 having a cylindrical surface 17 on its inner periphery and an inner race 12 having cam surfaces 18 on its outer periphery. An opposed pair of rollers 25 are mounted in each of pockets 24 defined between pillars 21 and 23 of the respective retainers 19A and 19B. A presser member 26 is also mounted in each pocket 24 which biases the pair of rollers 25 away from each other while pressing the rollers against the cam surface 18. A plurality of torque cams 40 are provided between flanges 20 and 22 of the control retainer 19A and the rotary retainer 19B. When the control retainer 19A is moved toward a rotor 52 by the actuation of an electromagnetic clutch 50, the torque cams 40 rotate the control retainer 19A and the rotary retainer 19B in the direction in which the circumferential width of the pockets 24 decreases, thereby disengaging the opposed pairs of rollers 25. When the control retainer 19A is moved away from the rotor 52, the control retainer 19A and the rotary retainer 19B are rotated relative to each other in the direction in which the circumferential width of the pockets 24 increases under the biasing force of the presser members 26, thereby engaging the rollers 25. While the inner race 12 is idling, the presser members 26 prevent the rollers 25 from moving radially outwardly, thereby preventing erroneous engagement of the rollers 25.
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