Friction engaging device

A wet friction engaging device for switching transmission of power to be output to a rotary shaft, the device comprising:

• two connecting members, each having a surface facing a surface of the other connecting member in a radial direction with a plate housing chamber interposed therebetween, the chamber being supplied with lubricating oil;
• a plate group engaged with the connecting members and including two groups of friction plates housed in the plate housing chamber and alternately arranged in an axial direction with surfaces facing each other;
• and
• a piston moving between an input side and an output side in the axial direction toward the plate group to apply a pressing force to the plate group, wherein
• the plate group is switched between an engaged state in which the friction plates are in close contact with each other upon application of the pressing force and a disengaged state in which the friction plates are separable from each other upon release of the pressing force,
• 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 biasing member to be separated from the stationary end plate in the axial direction,
• the movable end plate is the end plate on a side closer to the piston,
• the stationary end plate is positioned by stacking a regulator plate on and outside the end plate on a side away from the piston and having a first movement regulator at one side of these plates and a second movement regulator at the other side to restrict axial movement, and
• the biasing member is a spring, which is attached between the movable end plate and the regulator plate.