Abstract: A one-way clutch comprises an inner ring, an outer ring concentric with the inner ring, clutch members disposed between the inner and the outer rings and allowing rotation only in one direction, and a centering block disposed between adjacent clutch members. The centering block includes a sliding portion slidably contacting one of the inner and outer rings, a pair of fixed portions fixed to the other of the inner and outer rings, and two supporting portions connecting the sliding portion and the fixed portions. A respective lubricating oil hole is provided in at least one supporting portion and/or the sliding portion.

Abstract: A retainer plate of a one-way clutch assembly for retaining the one-way clutch assembly in position between a pair of outer and inner rings. The retainer plate is generally ring-shaped and recessed at a plurality of locations at least at one surface, so that when the retainer plate is brought into contact with the outer ring for having the retainer plate fixedly attached to the outer ring, there are formed a plurality of radially extending flow passages between the retainer plate and the outer ring. Therefore, a part of the lubricant supplied through a supply port of the inner ring may pass through these flow channels to be supplied to thrust bearings and/or to a clutch plate assembly which is provided at the outer periphery of the outer ring.