A wet-type multi plate clutch is configured to be used for a transmission in an automobile. A clutch pack is provided with a plurality of drive plates and a plurality of driven plates. The drive plates have single surfaces on which first clutch facings are fixed and opposed surfaces on which annular grooves are formed along entire peripheral lengths. The driven plates have single surfaces on which second clutch facings are fixed and opposed surfaces on which annular grooves are formed along entire peripheral lengths. The sliding surfaces of the drive plates and the driven plates are arranged between the first and second clutch facings, which are axially adjacent with each other.

A friction plate (1.sub.1) includes a plate (1A) with a disc shape and a friction material (F1, F2) that is fixed to aside face (1a) of the plate (1A). The friction material (F1, F2) is disposed so that one or both of an inner peripheral side and an outer peripheral side is nonuniform in an inner and outer peripheral direction with respect to a circumferential direction around a center (CT1) of the plate (1A). Thus, there is an increase in the amount of lubrication oil that is fed to a surface of friction material segments (F1, F2) and there is an increase in a separation force in an axial direction between a friction plate (1.sub.1) and a separator plate or an end plate.

A friction material presents a friction generating surface and a bonding surface facing opposite the friction generating surface. The friction material includes an organopolysiloxane resin, a plurality of fibers, and a plurality of friction particles. The organopolysiloxane resin includes siloxy units independently represented by the following formula: (R.sub.1SiO.sub.3/2) and/or (R.sub.2SiO.sub.2/2); wherein each R.sub.1 and R.sub.2 is independently selected from a monovalent hydrocarbon group having from 1 to 20 carbon atoms.

A friction disk may comprise a friction disk core and a wear liner coupled to the friction disk core. A depression may be formed in a surface of the friction disk core. The wear liner may comprise a protrusion extending from a non-wear surface of the wear liner. The protrusion may be positioned within the depression of the friction disk core.

A wet friction member includes a core plate formed in a flat ring shape; and a friction part arranged on a main surface of the core plate. The friction part is formed in such a manner that four kinds of segment pieces, which are a first piece, a second piece, a third piece, and a fourth piece, are repeatedly arranged in this arrangement order in a ring shape via oil grooves.

A wet friction member includes a core plate formed in a flat ring shape; and a friction part arranged on a main surface of the core plate. The friction part is formed in such a manner that four kinds of segment pieces, which are a first piece, a second piece, a third piece, and a fourth piece, are repeatedly arranged in this arrangement order in a ring shape via oil grooves.

A friction disk includes a friction disk core having an inner diameter edge, an outer diameter edge, and a first surface with multiple mortises extending radially across the first surface, each of the multiple mortises having a different dimension at the inner diameter edge than at the outer diameter edge. The friction disk further includes a first wear liner having two wear liner segments each including a wear surface and a non-wear surface having a tenon with a complimentary shape to each of the multiple mortises, the tenon being configured to be received by a corresponding mortise of the multiple mortises to couple the wear liner segments to the friction disk core to form an annular liner.

A friction plate for a clutch includes a face and a first friction material disposed on the face. The first friction material has a first composition including a first filler material at a first weight concentration of a total weight of the first friction material. A second friction material is disposed on the face and has a second composition that is different than the first composition and including a second filler material at a second weight concentration of a total weight of the second friction material. The second weight concentration is higher than the first weight concentration.

A wet multi-plate clutch includes a plate carrier with a pair of fluid passage openings and a friction plate rotationally fixed and axially displaceable relative to the plate carrier. The friction plate has a carrier element and a pair friction pads fastened to the carrier element and delimiting a groove. The groove includes a groove geometrical center line. The groove geometrical center line may extend radially through a one of the pair of fluid passage openings, or it may extend radially between the pair of fluid passage openings. If the groove geometrical center line extend radially between the pair of fluid passage openings, one of the pair of friction pads may include a pad geometrical center line extending along a radial extent through a one of the pair of fluid passage openings.

A brake pad having a backing plate, friction lining, and a surface coating adhered to the friction lining. The surface coating may be formulated to generate a transfer layer on a brake rotor faster than the friction lining alone. The surface coating may be adhered to the friction lining in a predetermined design.