A wet friction material includes a base including a matrix of fibers and filler particles embedded in the matrix of fibers; a binder embedded in an interior of the base; and a quaternary ammonium salt containing coating on an outer surface of the base. The quaternary ammonium salt containing coating can include a quaternary ammonium salt and a solution binder.

A clutch assembly for a motor vehicle drivetrain includes a rigid support and a wet friction material fixed to a surface of the rigid support. The wet friction material includes a base material including a matrix of fibers and filler particles embedded in the matrix of fibers. The filler particles include calcined kaolin clay, and the base material includes, by percent weight, 5 to 60% of calcined kaolin clay. The wet friction material also includes a binder embedded in the base material. The binder is tung modified phenolic resin.

A clutch assembly for a motor vehicle drivetrain includes a rigid support and a wet friction material fixed to a surface of the rigid support. The wet friction material includes a base material including a matrix of fibers and filler particles embedded in the matrix of fibers. The filler particles include calcined kaolin clay, and the base material includes, by percent weight, 5 to 60% of calcined kaolin clay. The wet friction material also includes a binder embedded in the base material. The binder is tung modified phenolic resin.

Provided are a wet friction plate and a wet multiplate clutch device including the wet friction plates capable of improving the performance for discharging lubricant oil adhering to surfaces of friction members. A wet friction plate includes oil grooves and friction members on a flat plate annular core metal. At a surface of a porous layer of the friction member, a friction slide surface and lubricant oil recessed portions are formed. The lubricant oil recessed portion has no sharp portion in a pointed shape, such as a corner portion, and is formed with a smooth continuous surface. The multiple lubricant oil recessed portions depressed in a recessed shape with respect to the friction slide surface are formed. In the porous layer, hollow portions are formed to have the same formation rate between a portion forming the friction slide surface and a portion forming the lubricant oil recessed portion.

Provided are a wet friction plate and a wet multiplate clutch device including the wet friction plates capable of improving the performance for discharging lubricant oil adhering to surfaces of friction members. A wet friction plate includes oil grooves and friction members on a flat plate annular core metal. At a surface of a porous layer of the friction member, a friction slide surface and lubricant oil recessed portions are formed. The lubricant oil recessed portion has no sharp portion in a pointed shape, such as a corner portion, and is formed with a smooth continuous surface. The multiple lubricant oil recessed portions depressed in a recessed shape with respect to the friction slide surface are formed. In the porous layer, hollow portions are formed to have the same formation rate between a portion forming the friction slide surface and a portion forming the lubricant oil recessed portion.

A power transmission device includes a friction clutch, an actuator, and a controller configured to determine an approximated temperature change of the friction clutch. The controller is configured to determine a current power state of the friction clutch, determine a desired power state change based on the current power state and a previous power state, determine a plurality of thermal coefficients based on a thermal coefficient model, the desired power state change, and a set of operation variables, determine an approximated temperature change of the friction clutch based on the thermal coefficients and a friction clutch temperature model, determine an approximated clutch temperature based on the approximated temperature change and a contemporaneous value of an device ambient temperature, and control operation of the actuator based at least on the approximated clutch temperature.

A hybrid module for a drive train of a motor vehicle includes a housing, an electric machine disposed within the housing. The electric machine having a stator and a rotor arranged radially within the stator. The hybrid module having at least one hydraulically cooled friction clutch arranged radially within the rotor. A cooling device is provided that is configured to cool a plurality of friction surfaces of the at least one friction clutch and which has an annular collecting region coupled to the rotor for conjoint rotation therewith and entraining a hydraulic medium during operation, as well as a scoop section, which is secured to the housing and projects into the collecting region and via which the hydraulic medium is fed to a retaining chamber during operation.

A hybrid module for a drive train of a motor vehicle includes a housing, an electric machine disposed within the housing. The electric machine having a stator and a rotor arranged radially within the stator. The hybrid module having at least one hydraulically cooled friction clutch arranged radially within the rotor. A cooling device is provided that is configured to cool a plurality of friction surfaces of the at least one friction clutch and which has an annular collecting region coupled to the rotor for conjoint rotation therewith and entraining a hydraulic medium during operation, as well as a scoop section, which is secured to the housing and projects into the collecting region and via which the hydraulic medium is fed to a retaining chamber during operation.

A friction engagement device of an automatic transmission is provided with a cylindrical drum part supporting an annular friction plate. The drum part includes a cylindrical body with a spline part having serrations extending in the axial direction and depressed radially outward to fit with the friction plate, in an inner circumferential side surface, a vertical wall part provided at an end side of the cylindrical body and extending radially inward, and a corner part provided between the cylindrical body and the vertical wall part. A drum recess is formed inside the corner part, connected to the serration and depressed toward an axial end side. A cut part is provided outside the corner part, connected to the drum recess, and cut in the circumferential direction of the drum part. The drum recess is opened to an outside by the cut part to form an oil gallery.

A wet-type friction engaging device includes a first friction member and a second friction member defining a groove formed on a surface of a base facing the first friction member.