A wet friction disc includes a friction surface and a lubrication groove through which a lubricant supplied to the friction surface flows. The lubrication groove has a plurality of circumferential groove portions that extends in a circumferential direction and a plurality of intersecting groove portions that extends in directions intersecting the circumferential direction. At least one of the circumferential groove portions has a through-hole that extends through the wet friction disc between an opposite surface facing s mating member and a surface on the opposite side in an axial direction.

A method for producing friction discs for a, in particular radial, dual clutch, includes the following steps: providing a first disc ring with a first inner diameter, providing a second disc ring with a second outer diameter, wherein the second outer diameter is smaller than the first inner diameter, and processing the first disc ring and the second disc ring in a tool for producing the friction discs. The second disc ring is arranged within the first disc ring, and the second and the first disc rings are processed in the tool together.

Provided are a joint component formed with fine recessed portions so that degradation of the flatness of a metal base body, such as a core, to which a joint object such as a friction member is joined can be reduced, a multiplate clutch device including the joint component, and a joint component manufacturing method. At a friction plate (200) as the joint component, many fine recessed portions (204) are formed at a joint surface (203) as a portion of a core (201) joined to friction members (207). The joint surface (203) is formed in a circular ring shape along a peripheral direction of the core (201), and is formed with a flatness of equal to or less than 0.15 mm. The fine recessed portions (204) are formed at the joint surface (203) such that adjacent ones of the fine recessed portions (204) do not overlap with each other and a formation density per unit area (Ua) at the joint surface (203) is uniform. The fine recessed portions (204) are formed as laser processing marks formed at the core (201) by irradiation with laser light L.

A hybrid drive train for a motor vehicle having an internal combustion engine, an electric machine, a first clutch, which is provided for coupling a crankshaft of the internal combustion engine to the rotor, and a second further clutch, which is designed as a wet clutch and which has a clutch cover. A screw connection is provided for non-rotatably connecting the rotor to the clutch cover, which screw connection includes a screw, which is substantially arranged in an axial direction and which at least partially penetrates a connecting piece non-rotatably fastened to the clutch cover.

A friction material presents a friction-generating surface and a bonding surface opposite the friction-generating surface. The friction material includes unbranched fiber having a diameter of from 0.5 to 50 μm and a length of from 0.2 to 15 mm, branched fiber having a diameter of from 1 to 50 μm, and a resin disposed throughout the friction material. The friction material is substantially free of particles and defines a plurality of pores having a pore size distribution with a D10 value of from 5 to 15 μm, a D50 value of from 15 to 30 μm, and a D90 value of from 30 to 60 μm.

Provided are a wet friction plate and a wet multiplate clutch device capable of reduction drag torque while suppressing a decrease in the area of a friction member. The wet friction plate includes multiple friction members through oil grooves on a flat plate annular core metal. The friction member has first fine grooves opening at an inner peripheral edge of the friction member and extending to an outer peripheral edge side and second fine grooves opening at an outer peripheral edge of the friction member and extending to an inner peripheral edge side. The first fine groove and the second fine groove are formed to have a groove width of equal to or greater than 0.1 mm and equal to or less than 0.8 mm, and overlap portions overlapping with each other in a circumferential direction at the same position in a radial direction of the core metal.

A vehicle transmission includes a first rotating element, second rotating element, first retainer ring, and second retainer ring. The first rotating element has an exterior surface that defines a first ring groove. The second rotating element is configured to limit movement of friction plates during clutch engagement. The second rotating element is disposed about the exterior surface and has an interior surface that defines a second ring groove. The first retainer ring is disposed in the first ring groove. The second retainer ring is disposed in the second ring groove and thereby restricts movement of the first retainer ring in a radially outward direction.

The invention comprehends friction plates, typically fabricated of metal, having friction material that is disposed in multiple concentric bands disposed in interrupted or discontinuous segments or a combination of both. In a first embodiment, the friction material is arranged in two concentric bands on each face, an inner band having a smaller radial width and an outer band having a larger radial width. In a second embodiment, the inner band is replaced with a plurality of discontinuous sections or segments wherein their circumferential separation is greater than their circumferential length. A third embodiment is similar to the second embodiment except that the inner, discontinuous segments have a circumferential length greater than their circumferential separation.

A torque transmitting device for an automotive transmission includes a clutch housing with a plurality of internal splines, a clutch hub with a plurality of external splines extending radially outwardly from the clutch hub, a plurality of friction plates with internal teeth and a first and a second surface. The first and second surface having a friction material disposed thereon and at least one of the internal teeth has an aperture and the plurality of internal teeth intermesh with the plurality of external splines on the outer surface of the clutch hub, a plurality of reaction plates having a plurality of external teeth and a first and a second surface. The plurality of external teeth intermesh with the plurality of internal splines in the clutch housing, and a spacer member disposed in the aperture separates a first of the friction plates from a second of the friction plates.

There is provided a method for producing a wet friction plate that can improve the retention property of lubricating oils in a fine groove formed by laser light. In a method for producing a wet friction plate (200), a friction material (210) is produced by sheet making processing in a first step. Thereafter, in a second step, a fine groove (211) is formed on the friction material (210). The friction material (210) is produced such that thermosetting resin therein is in a semi-cured state. The cross-sectional shape of the fine groove (211) is formed into a V shape by laser light. Subsequently, in a third step, the friction material (210) is disposed on a core metal (201) via an adhesive agent including thermosetting resin. Subsequently, in a fourth step, the friction material (210) is pressed while heated to crush the fine groove (211). In this manner, unevenness is formed on an intra-groove surface (212), and the thermosetting resin is completely cured.