Abstract: The present invention provides a wet type multi-plate clutch comprising a friction plate including friction materials secured to both surfaces of a core plate provided at its inner diameter side with a spline portion, a notch groove opened to the inner diameter side and having a terminal portion positioned between the inner diameter side and the outer diameter side and a through groove extending from the inner diameter side to the outer diameter side, and a separator plate provided at its outer diameter side with a spline portion, and wherein a retracting amount at the inner diameter side of the friction material secured to the friction plate is greater than a retracting amount at the outer diameter side.

Abstract: The present invention provides a friction plate for a wet-type multi-plate clutch, to which a wet-type friction material is secured and in which there are provided an oil passage communicated with inner and outer peripheral edges, an oil groove opened toward the inner peripheral edge and having a terminal end disposed between the inner peripheral edge and the outer peripheral edge, and at least one circumferential groove communicated with the oil passage and extending in a circumferential direction.

Abstract: The present invention provides a friction plate for a wet-type multi-plate clutch, to which a wet-type friction material is secured and in which there are provided an oil passage communicated with inner and outer peripheral edges, an oil groove opened toward the inner peripheral edge and having a terminal end disposed between the inner peripheral edge and the outer peripheral edge, and at least one circumferential groove communicated with the oil passage and extending in a circumferential direction.

Abstract: A separator plate useful in a wet-type multiplate clutch is provided on a friction surface thereof with elongated asperities extending with regularity in a predetermined direction. Peak portions of the elongated asperities, said peak portions being to project toward a counterpart member when the separator plate is assembled in the wet-type multiplate clutch, have been removed to form elongated plateaus. The separator plate can be manufactured by fixedly mounting a blank for the separator plate on a work support, forming elongated asperities with regularity in a predetermined direction on one of opposite surfaces of the blank by a grinding wheel, and then removing peak portions of the elongated asperities, said peak portions being to project toward a counterpart member when the separator plate is assembled in the wet-type multiplate clutch, to form elongated plateaus.

Abstract: A separator plate useful in a wet-type multiplate clutch is provided on a friction surface thereof with elongated asperities extending with regularity in a predetermined direction. Peak portions of the elongated asperities, said peak portions being to project toward a counterpart member when the separator plate is assembled in the wet-type multiplate clutch, have been removed to form elongated plateaus. The separator plate can be manufactured by fixedly mounting a blank for the separator plate on a work support, forming elongated asperities with regularity in a predetermined direction on one of opposite surfaces of the blank by a grinding wheel, and then removing peak portions of the elongated asperities, said peak portions being to project toward a counterpart member when the separator plate is assembled in the wet-type multiplate clutch, to form elongated plateaus.