Abstract: A segment-type friction material comprises segment pieces each having a supply passage formed thereon to supply lubricating oil to a surface of each of the segment pieces. The segment-type friction material further comprises oil grooves each having an outer peripheral opening portion extended in a curved shape or a linear shape. Thereby, lubricating oil is sufficiently supplied to the surface of each of the segment pieces from an outer peripheral side thereof or an inner peripheral side thereof and a clearance between the segment-type friction material and its associated separator plate is assured. Moreover, a space for the lubricating oil to flow through an outer periphery is sufficiently assured and a drag torque is reduced.

Abstract: A segment-type friction material comprises segment pieces each having a supply passage formed thereon to supply lubricating oil to a surface of each of the segment pieces. The segment-type friction material further comprises oil grooves each having an outer peripheral opening portion extended in a curved shape or a linear shape. Thereby, lubricating oil is sufficiently supplied to the surface of each of the segment pieces from an outer peripheral side thereof or an inner peripheral side thereof and a clearance between the segment-type friction material and its associated separator plate is assured. Moreover, a space for the lubricating oil to flow through an outer periphery is sufficiently assured and a drag torque is reduced.

Abstract: Provided is a wet friction material that includes a ring shaped flat metal core and a plurality of segment-type friction material substrates joined onto one or both of surfaces of the ring shaped flat metal core with an adhesive and spaced apart along an entire circumference of the ring shaped flat metal core to form a plurality of oil grooves extending in a radial direction of the core metal by a clearance between adjacent ones of the above segment pieces. One or both of outer peripheral corner portions of each of the plurality of segment-type friction material substrates is chamfered to form a chamfered part such that a width of the oil grooves adjacent the chamfered part of the corner portions is larger than a width of a thinnest portion of the above plurality of the oil grooves.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: In a wet friction material, to be able to obtain a more significant drag torque reduction effect certainly even in case of a specification that there is no lubricating oil supply from an inner peripheral side or in case that a stirred torque increases by generating oil retained at an outer periphery. In case of the specification (without axis core lubrication) that there is no lubricating oil (ATF) supply from the inner peripheral side of the wet friction material, that is, in case that there is the lubricating oil supply only from the outer peripheral side, in segment-type friction materials 1, 1A and 1C, by making R processing or chamfering processing to one or both corner portions of the outer periphery of segment pieces 3, 3A, 3B and 3C, it can obtain a significant drag torque reduction effect by a peeling effect that ATF runs from the processing portion into front surfaces of the segment pieces 3, 3A, 3B and 3C and goes into between a counterpart material.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A wet-type segmented friction material has a tape-like friction material substrate which is passed through and pressed between a roller having a dent at a center and a flat roller. At the same time, the friction material substrate is heated from an inside and an outside of the rollers so as to carry out a heat press compression processing. Then, a processed friction material substrate has a predetermined cross-section. The processed friction material substrate is cut into segment pieces each having a segment shape by a rotary push cutter having a sharp cutting edge. A cut position of the segment piece is selected such that two straight lines at two lateral sides of the segment shape is located within an area of a compressed portion of the processed friction material substrate. That is, a stepped or sunken compressed portion is provided on both sides of the segment piece.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the friction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the fiction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A friction material has a resin amount distribution that is the largest at a portion near a non-friction surface, that becomes lower toward an inside and that is the lowest at a portion near a friction surface. For example, such friction material is manufacture as follows. First, two friction materials are overlapped while the friction surfaces faced with each other. Then, the friction materials are dried at a room temperature. At this time, the resin has such a characteristic as to move while dragged by a solvent that dries from the non-friction surface located outside. Using such characteristic, the resin amount at the portion near the friction surface is lessened. Then, a temperature at the friction surface is made low and a temperature at the non-friction surface is made high in a drying step of the fiction material. Thereby, the resin amount at the portion near the friction surface is lessened.

Abstract: A wet friction material and its manufacturing method are provided. The wet friction material has a substrate having a surface and a very superficial layer. The very superficial layer is provided on the surface of the substrate and contains resin and fibers. The resin and the fibers are heated by one of a laser beam, a heating plate and a heating roller so as to thermally change the very superficial layer in a short period of time. Such manufacturing method is capable of evenly carbonizing the resin and the fibers of the very superficial layer of a friction surface of the wet friction material so as to flexibly deal with a variety of size of products.

Abstract: A wet-type segmented friction material has a tape-like friction material substrate which is passed through and pressed between a roller having a dent at a center and a flat roller. At the same time, the friction material substrate is heated from an inside and an outside of the rollers so as to carry out a heat press compression processing. Then, a processed friction material substrate has a predetermined cross-section. The processed friction material substrate is cut into segment pieces each having a segment shape by a rotary push cutter having a sharp cutting edge. A cut position of the segment piece is selected such that two straight lines at two lateral sides of the segment shape is located within an area of a compressed portion of the processed friction material substrate. That is, a stepped or sunken compressed portion is provided on both sides of the segment piece.

Abstract: A wet friction material and its manufacturing method are provided. The wet friction material has a substrate having a surface and a very superficial layer. The very superficial layer is provided on the surface of the substrate and contains resin and fibers. The resin and the fibers are heated by one of a laser beam, a heating plate and a heating roller so as to thermally change the very superficial layer in a short period of time. Such manufacturing method is capable of evenly carbonizing the resin and the fibers of the very superficial layer of a friction surface of the wet friction material so as to flexibly deal with a variety of size of products.