| 摘要 |
A control valve arrangement is disclosed for regulating fluid communication between a source of fluid under pressure and a double-acting hydraulic motor, including a housing defining a bore, an inlet chamber in communication with the bore and the pressure source, a pair of service chambers in communication with the bore and the hydraulic motor for actuation thereof, and a plurality of drain passages in communication with the bore, a pressure transmitting circuit defined in the housing and in communication with the bore, a relief valve which is in responsive communication with the pressure transmitting circuit for variably controlling the pressure in the inlet chamber, and a spool reciprocably disposed in the bore of the housing and having a plurality of lands for blocking communication between the inlet chamber and the service chambers in a neutral position, with the spool having metering slots for communicating fluid from the inlet chamber radially outwardly to a selected one of the service chambers and to the motor for operation thereof and for communicating return fluid from the other service chamber radially inwardly to a drain passage in a working position, and with the spool having openings for communicating the pressure transmitting circuit with a drain passage and unloading the relief valve in the neutral position and also for communicating the selected one of the service chambers to the circuit for loading the relief valve in the working position.
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