| 摘要 |
A power steering system (10) for use in a vehicle includes a power steering pump (12) which is driven by an engine (13) of the vehicle. The output from the power steering pump (12) is connected to a power steering valve (22). The power steering valve (22) is connected with a power steering motor (24). When the engine (13) is turned off, that is, in a non-operating condition, and the power steering pump (12) is not being driven, the fluid pressure in motor cylinder chambers (40, 42) is prevented from falling below a predetermined pressure to keep seals (64, 66) in sealing engagement with the power steering motor 24. To keep the fluid pressure in the motor cylinder chambers (40, 42) from falling below a predetermined pressure, a one-way valve (70) blocks the flow of fluid from the power steering valve (22) back to the reservoir (16). A pressure relief valve (72) blocks the flow of fluid from the power steering valve (22) to the reservoir (16) when the fluid pressure in the motor cylinder chambers (40, 42) is equal to or less than the predetermined pressure required to urge seals (64, 66) into sealing engagement with the power steering motor 24. <IMAGE> |
