| 摘要 |
<p>PCT No. PCT/JP93/01781 Sec. 371 Date May 22, 1995 Sec. 102(e) Date May 22, 1995 PCT Filed Dec. 8, 1993 PCT Pub. No. WO94/13960 PCT Pub. Date Jun. 23, 1994A turning-purpose hydraulic circuit characterized in that a discharge passage (20a) of a hydraulic pump (20) is connected to a variable relief valve (21) and a pump port of a directional switching valve (22); a first actuator port and a second actuator port (25, 26) of the said directional switching valve are connected to a turning-purpose hydraulic motor (27); the pilot pressure of a pilot valve (33) is introduced into pressure chambers (31, 32) for controlling a spool in the said directional switching valve and is also introduced into a pressure chamber (40) for controlling a set pressure in the said variable relief valve; a metering-in side portion (42) along which a pressurized oil flows from the said pump port of the said spool to the first or second actuator port is formed with a portion having a configuration such that a flow force may not be produced thereat; and a metering-out side portion (45) along which the pressurized oil flows from the first or second actuator port of the said spool to a tank port is formed with a portion having a configuration such that a flow force may be produced thereat.</p> |
