Patent ID: 8061498

Claim:
A wet clutch friction plate for use with a clutch plate, the friction plate comprising: a core plate disposed opposite the clutch plate and rotatable relative to the clutch plate; and friction material bonded to a side face of the core plate and disposed between the clutch plate and the core plate, wherein a plurality of oil channels are defined in the friction material and provide communication between inner and outer peripheral edges of the friction material, wherein the plurality of oil channels include a plurality of discharge oil channels, each discharge oil channel having a discharge angle (β) relative to a radial line (L) of the friction plate passing through an inner end of the discharge oil channel itself and which are configured to discharge oil from an inner peripheral side to an outer peripheral side of the friction plate due to a screw pump action that occurs when the friction plate rotates relative to the clutch plate, and the plurality of oil channels further include a plurality of inflow oil channels, each inflow oil channel having an inflow angle (α) relative to the radial line (L) of the friction plate passing through an inner end of the inflow oil channel itself and which is configured to draw oil in from the outer peripheral side to the inner peripheral side of the friction plate due to the screw pump action that occurs when the friction plate rotates relative to the clutch plate, wherein the friction plate is divided into a plurality of regions (A) arranged in the peripheral direction, each region including a number of discharge and inflow oil channels that is equal to a number of discharge and inflow oil channels of the other regions, wherein in each of said regions, the number of discharge oil channels is less than the number of inflow oil channels, and wherein the discharge angle (β) inclines rearward relative to the radial line (L) and the inflow angle (α) inclines forward relative to the radial line (L).