| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the need for arrangement of a throttle and a check valve, simplify a system requiring a differential circuit, save space, and reduce costs by arranging a throttle of a return passage in a switching function of a direction switching valve. SOLUTION: When a piston 12 is advanced, a part of a return fluid delivered from a rod side cylinder chamber is introduced to a pump delivery line as an operating part by a passage 17 provided with a check valve 16 as one way valve. The other part is delivered to a tank line through a throttle 20 arranged in a passage in B-T flow of a first switching function of a solenoid valve. When the piston 12 is retreated, a solenoid valve 13 is switched to a third switching function position so as to communicate a pressure port and a cylinder port B with each other. Thereby the necessity for arranging the check valve is eliminated in order to avoid a throttle arranged in the passage, and the number of parts is reduced by the check valve. Furthermore, costs are reduced by means of spool throttle work compared with one check valve, and a space is saved.</p> |
