| 摘要 |
PURPOSE:To contrive transmission and disconnection of rotation in both right and left directions on an input side by providing the second holding member, correlated to a subgear of generating a differential speed corresponding to the rotation of an input gear, and making a sprag tiltable in a clutch acting position. CONSTITUTION:A number of teeth 2a of an input gear is, for instance, 53, when a number of teeth of a subgear 8 is set to 54, rotation of the gear 8 is delayed from rotation of the gear 2 by rotation of the same drive shaft. An inner side holding member 9, brought into press contact with the gear 8, has a differential speed relating to the rotation of the gear 2 to perform relative rotation in a left hand rotational direction before a stopper 9e of the member 9 is brought into contact with a left side surface of a square hole 11. Since a sprag 6, housed in a pocket of the member 9, falls in a reverse direction to the member 9, the sprag 6 is engaged with cylindrical surfaces 17, 18 to which outside and inside diameter side circular arc surfaces of the sprag 6 are opposed, and a clutch action possible condition is obtained. When a slip is generated in a rear wheel, a rotational speed of the drive shaft is increased, and turning force of the gear 2 is transmitted to an output gear 4 by increasing a rotational speed of the gear 2 faster than the rotational speed of a rotary shaft 1 to actuate a clutch.
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