Abstract: A clutch plate in an annular shape, the clutch plate includes: a plurality of lubricating grooves on one end face and the other end face of the clutch plate in an axial direction; and a plurality of windows passing through the clutch plate in the axial direction. The lubricating grooves are formed with plastic deformation, in a same phase on both the end faces, and extended up to outer peripheral edges and inner peripheral edges of both the end faces. A plurality of intersection points where the lubricating grooves intersect with each other are positioned in other areas than at least one of the outer peripheral edges, radially outer edges of the windows, radially inner edges of the windows, and the inner peripheral edges, of both the end faces.

Abstract: A wet-type friction clutch plate which keeps lubricant on a frictional slide face, stabilizes frictional torque transmission and suppresses shuddering noise. The wet-type friction clutch plate has the frictional slide face on which a grid of grooves is formed. The frictional slide face frictionally engages with an opposite clutch plate. At least one of the sectional shape and plan shape of each of the grooves is configured to provide the frictional slide face with a &mgr;-v characteristic such that &mgr; increases with an increase in v to prevent self-excited vibration during frictional engagement of the wet-type friction clutch plate with the opposite clutch plate, wherein &mgr; is a coefficient of friction on the frictional slide face and v is a relative rotational speed of the wet-type friction clutch plate relative to the opposite clutch plate.

Abstract: A wet-type friction clutch plate surely keeps lubricant on a frictional slide face, stabilizes frictional torque transmission, and suppresses shuddering noise.