摘要 |
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. Moreover, even in case that there is the lubricating oil (ATF) supply from the inner peripheral side, it can obtain a significant drag torque reduction effect because it can restrain the stirred torque resulting from ATF at the outer peripheral portion. |