| 摘要 |
A pressure compensated spool type directional control valve characterized in that it has a compensating piston which senses the pressure drop across a metering orifice whose flow area is determined by the position of the spool in the valve housing and which is operative to divert excess flow to the reservoir when the pressure drop across the metering orifice exceeds a predetermined value, said compensating piston being so operative in conjunction with the operation of any one of the spools of a plural spool directional control valve. The compensating piston may also be operated as an unloading valve to bypass pump output to the reservoir when the spool or spools of the directional control valve are in neutral position, or as a relief valve by employment of a pilot relief valve member in association with the side of the compensating piston which is exposed to pressure downstream of the metering orifice.
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