A multiple disc clutch apparatus configured to reduce the drag torque, the sticking torque, and simultaneously the weight of the multiple disc clutch apparatus. The apparatus can comprise substantially annular multiple clutch discs connected to an input-side from an engine; substantially annular multiple clutch plates alternately laminated with the clutch discs and connected to an output-side to a wheel; and frictional members secured on surfaces of the clutch discs opposing the clutch plates and adapted to press-contact with or separate from the clutch plates. A power from the engine can be transmitted to the wheel when the clutch discs and plates are press-contacted with each other; the power transmission being blocked by releasing the press-contacting force; wherein depressions are formed on each clutch plate along its periphery and radially inward therefrom; and wherein a part of the one or more frictional members is positioned within a region of the depressions.

A wet friction disk that can achieve a further reduction in the drag torque, which includes a ring-shaped core plate having a wave shape in a circumferential direction thereof, a friction member disposed on a principal surface of the core plate so as to being substantially shaped into a ring with a plurality of oil grooves, and the oil grooves each have a shape with a groove width that is narrowed from an inner circumference side toward an outer circumference side of the core plate.

A clutch plate includes first and second axially offset annular surfaces, a first angled surface extending at an acute angle from the first annular surface in a first axial direction, and a second angled surface extending at an acute angle from the first annular surface in a second axial direction, opposite the first axial direction. In some example embodiments, the clutch plate has a wet friction material fixed to the first and second annular surfaces and at least one of the first and second angled surfaces. In an example aspect, the clutch plate has a low friction wet friction material fixed to the wet friction material of the at least one of the first and second angled surfaces. The low friction wet friction material may be fixed to the wet friction material by infusion or bonding. In an example embodiment, the clutch plate has a first wet friction material fixed to the first and second annular surfaces, and a second, low friction wet friction material fixed to at least one of the first and second angled surfaces.

Problem—To provide a friction plate with reduced drag torque.

Solution—The friction plate is formed with oil grooves having the sectorial shapes spreading toward the inner circumference and the perimeter. The adjacent edges of the friction material segments are provided with the perimeter side vertex and the inner circumference side vertex respectively. The sectorial oil groove opening toward the perimeter side from the inner circumferential side vertexes can discharge a lube oil to the perimeter side efficiently by a centrifugal force. Also, owing to the sectorial oil groove opening toward the inner circumference side from the perimeter side vertexes, a lube oil can be made to run aground onto the friction material segments due to a centrifugal force, thus, reducing the drag torque markedly compared with the conventional plates.

A multi-plate clutch is specified, with an outer plate carrier, an inner plate carrier and a plate pack which consists of alternately arranged outer plates and inner plates and is arranged radially between the outer plate carrier and the inner plate carrier, wherein a first group of the outer plates is mounted on the outer plate carrier and/or a first group of the inner plates is mounted on the inner plate carrier with a larger circumferential backlash than the other outer plates or inner plates, respectively, which are mounted on their plate carrier with no or smaller circumferential backlash, wherein the outer and/or inner plates with larger circumferential backlash in each case directly adjoin at least one plate with no or smaller circumferential backlash. Furthermore, an electrically operated drive train and a method for producing a multi-plate clutch are specified.

An improved clutch pack is disclosed. The clutch pack incorporates liners, improved driving friction disks and driven disks where the thickness of the improved driving friction disks and driven disks are selected in order to allow more driving friction disks and more driven disks to be used within the improved clutch pack while maintaining approximately the same overall height as compared to the standard clutch pack the vehicles clutch system was designed for.

Provided are a method for manufacturing a wet friction plate, whereby efficiency of the work of forming a fine groove on a friction material can be improved, the wet friction plate, and a wet multiple-plate clutch device having the wet friction plate. In the method for manufacturing a wet friction plate 200, a core metal 201 and a friction material 210 are prepared, a resin layer 203 is formed on the core metal, the friction material is attached onto the resin layer, and a fine groove 211 is formed in the friction material. Specifically, irradiation of a laser beam L is started on an exposed portion 205 of the core metal. A laser head 301 is displaced in an annular shape while continuously emitting the laser beam. Thus, annular fine grooves 204 and 211 are formed in the exposed portion of the core metal and the friction material.

An improved expanding friction disk for use in a clutch of a power transmission system. The improved expanding friction disk accommodates multiple clutch pack configurations including clutch packs utilizing novel improved friction disks, is compatible with wear liners and operates with reduced friction including a reduced difference between the static and dynamic coefficients of friction in the ramp mechanism.

A friction plate for wet-running applications includes an annular main body having a first and a second surface. A friction lining having first oil grooves and second oil grooves is disposed on at least one of the first and the second surfaces. The first oil grooves extend from a radially inner end face of the friction lining in the direction towards a radially outer end face of the friction lining and terminate at a distance short of the radially outer end face, and the second oil grooves are disposed directly adjoining the first oil grooves in the radial direction and have a smaller maximum width in the circumferential direction than the first oil grooves. The first oil grooves are provided with a cross-sectional widening in the region of a radially outer end. The cross-sectional widenings of the first oil grooves are disposed at different radial heights.

Provided are a method for manufacturing a wet friction plate, whereby efficiency of the work of forming a fine groove on a friction material can be improved, the wet friction plate, and a wet multiple-plate clutch device having the wet friction plate. In the method for manufacturing a wet friction plate 200, a core metal 201 and a friction material 210 are prepared in a first step. Thereafter, a resin layer 203 is formed on the core metal 201 in a second step. The resin layer 203 is formed on each of entire two plate surfaces of the core metal 201. Subsequently, the friction material 210 is attached onto the resin layer 203 of the core metal 201 in a third step. Subsequently, a fine groove 211 is formed in the friction material 210 in a fourth step. Specifically, irradiation of a laser beam L is started on an exposed portion 205 of the core metal 201. A laser head 301 is displaced in an annular shape while continuously emitting the laser beam L. Thus, annular fine grooves 204 and 211 are formed in the exposed portion 205 of the core metal 201 and the friction material 210.