Provided is a frictional engagement device including outer and inner base bodies, outer and inner friction plates, a piston, a return spring, and a spring seat. Sliding grooves which guide sliding movement of the outer or inner friction plate in the axial direction are provided in at least one of the outer and inner base bodies at intervals in a circumferential direction, the outer or inner friction plate which slides in the sliding grooves includes protruding pieces fitted in the sliding grooves, a spring seat which is located on one end portion of each of the sliding grooves and supports one end of the return spring is provided on the outer or inner base body in which the sliding grooves are provided, and a through-hole which communicates with the sliding grooves and is capable of discharging lubricating oil that has accumulated in the sliding grooves is provided in the spring seat.

Provided is a frictional engagement device including outer and inner base bodies, outer and inner friction plates, a piston, a return spring, and a spring seat. Sliding grooves which guide sliding movement of the outer or inner friction plate in the axial direction are provided in at least one of the outer and inner base bodies at intervals in a circumferential direction, the outer or inner friction plate which slides in the sliding grooves includes protruding pieces fitted in the sliding grooves, a spring seat which is located on one end portion of each of the sliding grooves and supports one end of the return spring is provided on the outer or inner base body in which the sliding grooves are provided, and a through-hole which communicates with the sliding grooves and is capable of discharging lubricating oil that has accumulated in the sliding grooves is provided in the spring seat.

A friction plate includes a core plate. The core plate includes an interior core surface, an exterior core surface, a first clutch face having a first plane extending, and a second clutch face having a second plane. The friction plate also includes a friction material disposed on at least one of the first and second clutch faces. The core plate includes a plurality of projections. At least one of the projections extends away from the first and second planes with respect to the axis such that the at least one of the projections is configured to provide a spring force to the other friction plate of the clutch assembly during disengagement of the friction plate from the other friction plate, and to direct the lubricant axially away from the first clutch face along the axis during rotation of the core plate for limiting drag torque in the clutch assembly.

The present disclosure provides a wet friction engaging device. The device includes a plate group engaged with two connecting members and including two groups of friction plates housed in a plate housing chamber and alternately arranged in an axial direction with surfaces facing each other. The plate group is switched between an engaged state in which the friction plates are in close contact with each other, and a disengaged state in which the friction plates are separable from each other. End plates at respective ends of the plate group are kept at a larger distance in the axial direction after a switch to the disengaged state than in the engaged state.

The present disclosure provides a wet friction engaging device. The device includes: a plate group engaged with two connecting members and including two groups of friction plates housed in a plate housing chamber and alternately arranged; and a spring attached between a spring plate and an end plate. The plate group is switched between an engaged state in which the friction plates are in close contact with each other, and a disengaged state in which the friction plates are separable from each other. The spring plate is fixed to the end plate.

The present disclosure provides a wet friction engaging device. The device includes: a plate group engaged with two connecting members and including two groups of friction plates housed in a plate housing chamber and alternately arranged; and a spring attached between a spring plate and an end plate. The plate group is switched between an engaged state in which the friction plates are in close contact with each other, and a disengaged state in which the friction plates are separable from each other. The spring plate is fixed to the end plate.

The present disclosure provides a wet friction engaging device. The device includes: a plate group engaged with two connecting members and including two groups of friction plates housed in a plate housing chamber and alternately arranged in an axial direction with surfaces facing each other; and a piston configured to apply a pressing force to the plate group. The plate group is switched between an engaged state in which the friction plates are in close contact with each other, and a disengaged state in which the friction plates are separable from each other. One of end plates at respective ends of the plate group is a movable end plate movable in the axial direction, and the other is a stationary end plate immovable in the axial direction. The movable end plate is biased by a spring.

A friction engagement device includes a rotating shaft, first friction plates that rotate with the rotating shaft, second friction plates arranged to face the first friction plates, an oil chamber supplied with hydraulic fluid, a piston movably provided between engagement and release positions, and first and second return springs. Ihe piston is pressed toward the engagement position by hydraulic pressure of the oil chamber. The first return spring contacts the piston from the engagement position to a standby position between the release position and the engagement position and urges the piston toward the release position. The second return spring contacts the piston from he engagement position to the release position and urges the piston toward the release position. Center axes of the first and second return springs are arranged to coincide with a center axis of the rotating shaft.

A friction engagement device includes a rotating shaft, first friction plates that rotate with the rotating shaft, second friction plates arranged to face the first friction plates, an oil chamber supplied with hydraulic fluid, a piston movably provided between engagement and release positions, and first and second return springs. Ihe piston is pressed toward the engagement position by hydraulic pressure of the oil chamber. The first return spring contacts the piston from the engagement position to a standby position between the release position and the engagement position and urges the piston toward the release position. The second return spring contacts the piston from he engagement position to the release position and urges the piston toward the release position. Center axes of the first and second return springs are arranged to coincide with a center axis of the rotating shaft.

A clutch arrangement is formed with drive-side and, output-side clutch elements and a clutch piston for operative connection and disengagement between the drive-side and output-side clutch elements. Associated with at least two clutch elements is an elastically deformable clutch element working mechanism through which the corresponding clutch elements can be acted upon in direction away from one another by an axial force to assist disengagement of the drive-side and output-side clutch elements. The clutch element working mechanism provides a considerable change in the gradient of the axial force exerted on the clutch elements as a result of even a small change of shape of the clutch element working mechanism so that a sharply rising axial force of the clutch element working mechanism works against the clutch piston.