US Patent 7779980 Wet multi-plate clutch

The present invention provides a wet multi-plate clutch comprising an external toothed plate formed by sticking a friction material to a core plate and an internal toothed plate formed by sticking a friction material to a core plate and designed so that torque is transmitted by engaging the external toothed plate with the internal toothed plate and wherein the friction materials are stuck to opposed surfaces where the external toothed plate is opposed to the internal toothed plate, and surfaces of the core plates to which the friction materials are stuck are provided with a plurality of surfaces offset axially.