Clutch unit for vehicle
A clutch unit includes: an input-side transmission member provided to move from an initial position toward a tip of the wedge-shaped space, and an inside tangential line is a tangential line at a contact point of the input-side transmission member and the input-side inner ring member, an outside tangential line is a tangential line at a contact point of the input-side transmission member and the input-side outer ring member, and a segment connects a rotational center of the input-side transmission member with an intersection point between the inside tangential line and the outside tangential line, wherein a wedge angle is an acute angle defined by the segment and the inside tangential line, and a stopper projection is provided at a tip-side position, and a wedge angle formed by the stopper projection is larger than an initial wedge angle at the initial position.
1. A clutch unit used in a vehicle seat, comprising:
an operation lever, which is rotatable about a rotational axis line;
an output shaft member, which is rotatable about the rotational axis line and outputs an operating force that is input to the operation lever to the vehicle seat; and
an input-side clutch including:
an input-side inner ring member and an input-side outer ring member, which are provided coaxially with the rotational axis line and in which the output shaft member is inserted; and
an input-side transmission member, which is arranged in a wedge-shaped space formed between an outer circumferential surface of the input-side inner ring member and an inner circumferential surface of the input-side outer ring member,
wherein the input-side clutch transmits, through the input-side transmission member, a rotation of the operation lever to the output shaft member in such a manner that one member of the input-side inner ring member and the input-side outer ring member rotates according to the rotation of the operation lever to rotate the other member of the input-side inner ring member and the input-side outer ring member,
wherein the input-side transmission member is provided to move from an initial position toward a tip of the wedge-shaped space when an operation torque input to the operation lever is equal to or more than a predetermined torque, and
wherein as viewed in the rotational axis line direction,
an inside tangential line is a tangential line at a contact point of the input-side transmission member and the input-side inner ring member,
an outside tangential line is a tangential line at a contact point of the input-side transmission member and the input-side outer ring member, and
a segment connects a rotational center of the input-side transmission member with an intersection point between the inside tangential line and the outside tangential line,
wherein a wedge angle is an acute angle defined by the segment and the inside tangential line, and
wherein a stopper projection is provided at a tip-side position of the wedge-shaped space from the initial position, and a wedge angle formed by the stopper projection is larger than an initial wedge angle at the initial position,
wherein the stopper projection protrudes toward the wedge-shaped space from at least one of the outer circumferential surface of the input-side inner ring member and the inner circumferential surface of the input-side outer ring member, and
wherein the stopper projection is provided to release a wedge engagement of the input-side transmission member.
2. The vehicle clutch unit according to claim 1 ,
wherein the stopper projection is provided in one of the input-side inner ring member and the input-side outer ring member, and
wherein a hardness value of the input-side transmission member, a hardness value of one of the input-side inner ring member and the input-side outer ring member provided with the stopper projection, and a hardness value of the other of the input-side inner ring member and the input-side outer ring member not provided with the stopper projection are smaller in such an order.
3. The vehicle clutch unit according to claim 1 , wherein the wedge-shaped spaces are shaped to be tapered in a counterclockwise direction.
4. The vehicle clutch unit according to claim 1 , wherein the stopper projection is configured such that the wedge engagement of the input-side clutch is released so as not to transmit the operation torque of the input-side inner ring member to the input-side outer ring member.
5. The vehicle clutch unit according to claim 1 , wherein, in the initial position, the wedge angle in the initial position is set to θ1 and a static friction coefficient between the input-side clutch and the inner circumferential surface of the input-side outer ring member set to μ0, θ1 satisfies an expression of tan θ1<θ1.
6. The vehicle clutch unit according to claim 5 , wherein the wedge angle in the stopper projection is set to θ2, θ2 satisfies an expression of μ0<tan θ2.
7. The vehicle clutch unit according to claim 6 , wherein the wedge angle of the stopper projection θ2 is greater than the wedge angle θ1 of the initial position.
8. The vehicle clutch unit according to claim 1 , wherein the wedge angle in the stopper projection is set to θ2 and a static friction coefficient between the input-side clutch and the inner circumferential surface of the input-side outer ring member set to μ1, θ2 satisfies an expression of μ0<tan θ2.