A power unit includes: a crankcase which accommodates a crankshaft and a main shaft arranged in parallel to each other; a crank side cover which covers one end portion of the crankshaft from the outside in an axial direction of the crankshaft; a primary driven gear which is provided in the main shaft and meshes with a primary drive gear of the crankshaft; a clutch provided at one end portion of the main shaft; and a clutch cover which covers the clutch from the outside in an axial direction of the main shaft and is fastened and fixed to a packing surface provided on the crankcase to surround the clutch, wherein the primary driven gear and the packing surface overlap in a virtual straight line when viewed from the axial direction of the main shaft.

A power transmission device has a pressure member (5) pressing drive-side clutch plates and driven-side clutch plates against each other or releasing a press-contact force. A clutch spring (10) urges the pressure member (5) in a direction so that the clutch plates are pressed against each other. A separate receiving member (11) is attached to the pressure member (5). A back-torque limiting cam reduces press-contact force between the clutch plates when the rotation speed of an output member exceeds the rotation speed of an input member. A rotation restricting portion (8a) restricting rotation, relative to the clutch member (4), of the pressure member (5) that has moved due to activation of the push rod (9). A clearance t is maintained between the pair of cam surfaces that constitute the back-torque limiting cam.

A clutch device includes a first rotor, a second rotor, and a clutch plate. The first rotor includes a first slide surface. The second rotor includes a second slide surface disposed axially apart from the first slide surface. The second rotor is axially movable relative to the first rotor. The clutch plate is disposed between the first slide surface and the second slide surface. The first rotor includes an opposite surface that is axially opposite to the first slide surface. The opposite surface includes a plurality of recesses, a ribbed portion, and a coupling portion. The recesses are circumferentially aligned. The ribbed portion radially extends between each adjacent pair of the recesses. The coupling portion is disposed radially outside the recesses and circumferentially extends such that each adjacent pair of ribs in the ribbed portion is coupled therethrough.

Provided is a clutch friction plate and a clutch device configured so that stiction torque can be reduced and each of in gear, shift feeling, and neutral find can be smoothly performed. A clutch device (100) includes clutch friction plates (101). In the clutch friction plate (101), multiple small-piece-shaped friction members (103) are radially bonded to surfaces of a core bar (102) formed in a flat-plate annular shape through an oil groove (105). Each friction member (103) includes an outer side (104a) facing an outer edge portion of the core bar (102) and an inner side (104b) facing an inner edge portion of the core bar (102) and extending parallel to the outer side (104a), and is formed in a rectangular shape. The friction members (103) are bonded onto the core bar (102) in such a direction that the outer side (104a) and the inner side (104b) are inclined at an inclination angle (θ) with respect to a perpendicular line (CL) perpendicular to a line (OL) connecting the center (O1) of the core bar (102) as the center of rotation of the clutch friction plate (101) and the center (O2) of the friction member (103).

A power transmission device has a first clutch member 4a coupled to an output member 3. A second clutch member 4b has a plurality of driven-side clutch plates 7. A back-torque transmitting cam presses the drive-side clutch plates 6 and the driven-side clutch plates 7 against each other by moving the second clutch member 4b when a rotational force is input to the first clutch member 4a. A cushioning member 12 is interposed between the first clutch member 4a and the second clutch member 4b. The cushioning member 12, by being compressed, applies an urging force while allowing movements of an interlocking member 9 and a pressure member 5 in a process where the interlocking member 9 moves and the pressure member 5 moves from the inactive position toward the active position.

A shifting system includes an input member, a disconnect, an output member, and a shifting assembly to selectively rotationally couple the input member and the output member. The shifting assembly includes an input hub having a disconnectable component engageable with the disconnect and a clutch engagement component extending radially away from an axis. A plurality of clutch plates is coupled to the clutch engagement component and is moveable between engaged and disengaged positions. A biasing member is coupled to the clutch plates to bias the clutch plates toward the engaged position, and an apply plate is coupled to the biasing member. The apply plate is moveable between a first plate position where the clutch plates are in the engaged position, and a second plate position where the clutch plates are in the disengaged position. A clutch plate carrier is coupled to the clutch plates and to the output member.

A clutch apparatus is provided which includes a center clutch and a pressure clutch that can hold a clutch plate without falling off of the clutch plate and also prevent a reduction in strength. A clutch apparatus 100 includes a center clutch 105 and a pressure clutch 112, which hold clutch plates 104 placed facing friction plates 103 that are rotationally driven by a driving shaft. The center clutch 105 includes a center-side mating portion 108 mating with internal teeth of the clutch plate 104. In addition, the center-side mating portion 108 includes a protruding tooth 110. The pressure clutch 112 includes a pressure-side mating portion 116 mating with internal teeth of the clutch plate 104. In addition, the pressure-side mating portion 116 includes a run-off 117. The protruding tooth 110 extends over the run-off 117 of the pressure-side mating portion 116, as one of spline teeth forming the center-side mating portion 108.

A friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission includes a lamina, an axially movable contact plate, and a plurality of friction disks. The lamina has a first friction surface facing in a first axial direction, and a second friction surface facing in a second axial direction, opposite the first axial direction. The contact plate has a plurality of holders arranged to hold the lamina. Each of the holders forms a positive connection with the lamina in the circumferential direction, and each of the first friction surface and the second friction surface is frictionally connectible to a friction disk to transmit torque. A first friction disk is arranged to be positioned between a counter plate and the lamina, and a second friction disk is positioned between the lamina and the contact plate.

A friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission includes a lamina, an axially movable contact plate, and a plurality of friction disks. The lamina has a first friction surface facing in a first axial direction, and a second friction surface facing in a second axial direction, opposite the first axial direction. The contact plate has a plurality of holders arranged to hold the lamina. Each of the holders forms a positive connection with the lamina in the circumferential direction, and each of the first friction surface and the second friction surface is frictionally connectible to a friction disk to transmit torque. A first friction disk is arranged to be positioned between a counter plate and the lamina, and a second friction disk is positioned between the lamina and the contact plate.

A clutch assembly comprises an input shaft and an output shaft, co-axially arranged relative to the input shaft. The clutch assembly further comprises an input clutch drum, fixed to the input shaft, and an output clutch drum, translatable relative to the output shaft. The clutch assembly further comprises a clutch pack and a clutch piston that is translatable relative to the output shaft between, inclusively, a frictionally disengaged clutch-pack position and a frictionally engaged clutch-pack position. The clutch assembly additionally comprises a clutch-pack engagement spring. The output clutch drum is translatable between, inclusively, a fully disengaged position and, inclusively, a positively engaged position. When the clutch piston is in the frictionally disengaged clutch-pack position, the internal splines of the output clutch drum are not in mesh with the external splines of the input clutch drum.