Abstract: Fluid distributing apparatus for radial piston-type hydraulic pumps or motors is disclosed. In the apparatus, a valve casing is mounted to a housing of the pump or motor. A plate valve is seated in the central portion of the valve casing and selectively rotates while maintaining a dynamic balance. A fluid distributing plate and a pressure plate are arranged in the valve casing and are brought into close contact with top and bottom surfaces of the plate valve, thereby allowing the plate valve to selectively rotate under the state of dynamic balance. A retaining ring is interposed between the fluid distributing plate and the pressure plate and surrounds the plate valve, thereby removing dynamic friction from relatively-moving portions of the plate valve, pressure plate and fluid distributing plate.

Abstract: The present invention provides a shuttle relief valve comprising a housing provided with left and right conduit holes respectively connected to the left and right conduits which are arranged between a pressure source and a hydraulic motor in a hydraulic circuit system, and a space portion communicating the conduit holes with each other. A spool is slidably disposed in the space portion so that the space portion is selectively opened or closed by the movement of the spool. A spring urges the spool into the position in which the space portion is closed, and a left cover is fitted in one hollow portion of the housing formed on one side of the space portion so that it supports the movement of the left portion of the spool. A bushing is fitted in the other hollow portion of the housing formed on the other side of the space portion so that it supports the movement of the right portion of the spool.