Patent ID: 7588112
Filing Date: 2009-09-15
Classification: F16D,F16H,Y10T

Abstract:
1. A bi-directional clutch comprising: an input portion; an input side rotor drivingly connected to the input portion; an output side rotor coaxially disposed inside the input side rotor, so as to make an annular space between an inner peripheral surface of the input side rotor and an outer peripheral surface of the output side rotor; a cage disposed in the annular space; a plurality of rollers held by the cage so as to be able to engage with both the inner peripheral surface of the input side rotor and the outer peripheral surface of the output side rotor, and to disengage from at least either the inner peripheral surface of the input side rotor or the outer peripheral surface of the output side rotor; an unrotatable portion; frictional engaging means frictionally engaging the cage with the unrotatable portion so as to allow the cage to be rotatable relative to the unrotatabe portion; a casing incorporating the input side rotor, the output side rotor, the cage, the rollers and the frictional engaging means; and rotation restricting means for restricting rotation of the cage holding the rollers, wherein, when a rotary speed of the output side rotor is larger than a rotary speed of the input side rotor, the output side rotor is isolated from the rotary force of the input side rotor, wherein, when a rotary speed of the output side rotor is smaller than a rotary speed of the input side rotor, the rollers engage with the inner peripheral surface of the input side rotor and the outer peripheral surface of the output side rotor so as to wedge the input side rotor with the output side rotor, thereby allowing the rotary force of the input side rotor to be transmitted to the output side rotor, and wherein the rotation restricting means temporarily restricts the rotation of the cage when a rotary direction of the input side rotor wedged with the output side rotor through the rollers is reversed, the rotation restricting means including: a receiving portion formed on an end surface of the cage; a forcible engaging member held by the casing so as to be prevented from rotating relative to the casing; a spring biasing the forcible engaging member so as to thrust the forcible engaging member toward the receiving portion; and a retainer for holding the forcible engaging member separated from the receiving portion, wherein, only when the rotary direction of the input side rotor is reversed, the retainer allows the forcible engaging member biased by the spring to thrust toward the receiving portion and finally engage with the receiving portion so as to restrict the rotation of the cage.