A reverse input blocking clutch has a pressed member having a pressed surface on the inner circumferential surface; an input member having an input-side engaging portion arranged on the inner side in the radial direction of the pressed surface and coaxially arranged with the pressed surface; an output member having an output-side engaging portion arranged further on the inner side in the radial direction than the input-side engaging portion and coaxially arranged with the pressed surface; an engaging element arranged on the inner side in the radial direction of the pressed surface so as to move in a first direction which is a far-near direction with respect to the pressed surface; and an elastic member arranged at a position overlapping the output-side engaging portion with respect to the first direction so as to be elastically stretched between the output-side engaging portion and the engaging element.

A structure of a rotation locking device that is easily configured and capable of keeping cost down is achieved.

A rotation locking device 4 switches between a first mode where an engaging claw portion 14 engages with an engaging concave portion 9 by an output member 13 rotating an engaging member 8 due to an input member 12 being rotationally driven by an actuator 7, and rotation of a locking gear 5 supported by and fixed to an output shaft 3 of an automatic transmission 2 is restricted, and a second mode where engagement between the engaging claw portion 14 and the engaging concave portion 9 is released and rotation of the locking gear 5 is allowed.

An assist mechanism includes: an electric motor in which a rotor has a magnet and a stator has a winding; a shaft-shaped member in which a worm engaged with a worm wheel is formed; and a coupling that couples an output shaft of the electric motor and the shaft-shaped member to each other. The smallest rotation order among rotation orders of the electric motor and a rotation order of the worm are prime to each other.

An assist mechanism includes: an electric motor in which a rotor has a magnet and a stator has a winding; a shaft-shaped member in which a worm engaged with a worm wheel is formed; and a coupling that couples an output shaft of the electric motor and the shaft-shaped member to each other. The smallest rotation order among rotation orders of the electric motor and a rotation order of the worm are prime to each other.

A coupling includes first and second annular flanges in spaced relation across a gap. At least one resilient element is disposed in the gap in abutting relation to the first and second annular flanges. A first plurality of fasteners extends from the first annular flange, through the at least one resilient element, to the second annular flange, and a second plurality of fasteners extends from the second annular flange, through the at least one resilient element, to the first annular flange. Fasteners in the first plurality of fasteners is disposed in alternating fashion with fasteners in the second plurality of fasteners.

[Problem] To realize a reverse input blocking clutch capable of suppressing looseness of an output member.

[Solution] The reverse input blocking clutch has a pressed member having a pressed surface 20 on the inner circumferential surface; an input member that has an input-side engaging portion 8 arranged on the inner side in the radial direction of the pressed surface 20, and is coaxially arranged with the pressed surface 20; an output member that has an output-side engaging portion 11 arranged further on the inner side in the radial direction than the input-side engaging portion 8 on the inner side in the radial direction of the pressed surface 20, and is coaxially arranged with the pressed surface 20; an engaging element 5 arranged on the inner side in the radial direction of the pressed surface 20 so as to be able to move in a first direction which is a far-near direction with respect to the pressed surface 20; and an elastic member 56 arranged at a position overlapping the output-side engaging portion 11 with respect to the first direction so as to be elastically stretched between the output-side engaging portion 11 and the engaging element 5.

A coupling has: a first coupler rotatable about an axis and defining first connections distributed about the axis; a second coupler defining second connections distributed about the axis, the second connections offset from the first connections; and segments distributed about the axis and extending radially from the first connections to the second connections, a segment of the segments having a first end engaging a first connection of the first connections and a second end engaging a second connection of the second connections, the first end circumferentially offset from the second end, a face of the segment abutting against a face of the first coupler when the segment is inserted into the first connection in a first orientation such that a penetration depth of the segment into the first connection in the first orientation is less than the penetration depth in a second orientation opposite the first orientation.

The rotation transmission state switching device comprises a clutch device comprising a first rotating member having a first-rotating-member-side engaging portion, a second rotating member having a second-rotating-member-side engaging portion, a third rotating member having a third-rotating-member-side engaging portion; and an engaging element having an engaging-element-side first engaging portion engaging with the first-rotating-member-side engaging portion, an engaging-element-side second engaging portion engaging with the second-rotating-member-side engaging portion, and an engaging-element-side third engaging portion engaging with the third-rotating-member-side engaging portion; and a restriction device configured to switch between allowing and restricting rotation of the first rotating member, allowing or preventing torque transmission between the second rotating member and the third rotating member.

A coupling structure includes a shaft, a tube, and a connection assembly. An end of the shaft is formed with a plurality of axial insertion troughs extended in an axial direction and arranged in an alternate manner. The tube includes a penetration-axle hole formed in a center thereof and corresponding to the penetration-axle section of the shaft. A plurality of radial insertion troughs, in the form of a recessed surface, are formed in an inner circumferential surface of the penetration-axle hole of the tube. The connection assembly includes a coupling block that has an outer circumference formed with a plurality of radial insertion blocks corresponding to the radial insertion troughs of the tube and a plurality of axial insertion blocks corresponding to the axial insertion troughs of the shaft, so that a fastening member may be used to selectively fasten the coupling block between the shaft and the tube.

Provided is a friction transmission device having a friction transmission mechanism that transmits power by contact between a take-out member from which output rotation is taken out and a plurality of friction rolling elements. The take-out member has a contact surface inclined with respect to an axial direction. The device includes an output member that is used to transmit the output rotation to a driven device, and a coupling that connects the take-out member and the output member to each other. The coupling is configured to be more easily deformed than the take-out member and the output member with respect to an axial load, and has a function of absorbing deviation of an axial center between the take-out member and the output member and a function of converting a torque acting on the output member into an axial force to transmit the axial force to a take-out member side.