| 摘要 |
PROBLEM TO BE SOLVED: To prevent an increase in sliding resistance by an inclination/eccentricity of a rod by introducing a part of a hydraulic fluid to a pressure pocket via an restrictor from a connecting passage when introducing the hydraulic fluid to a supply/ discharge passage, and generating thrust in a piston member. SOLUTION: A switching cycle for discharging a hydraulic fluid from the outer by introducing the hydraulic fluid to one of supply/discharge ports 8, 17 is performed at a high speed. When discharging the hydraulic fluid of the supply/discharge port 17 by introducing the hydraulic fluid to the supply/discharge port 8, a part of the hydraulic fluid of a supply/discharge passage 24 is introduced to a pressure pocket 31 from a connecting passage 30 of a piston member 26, and leaks a little to a chamber 23 from clearance 37 between a holder 28 and a pressure receiving plate 22 to generate pressure in the pressure pocket 31. When the hydraulic fluid passes through a restrictor 32, differential pressure is generated before and after this, upstream pressure acts on the piston member 26 to generate thrust to move a rod 2 in the leftward direction. At this time, since a space is imparted between the pressure receiving plate 22 and an inner peripheral surface of a cover tube 1, there is no possibility of increasing sliding resistance by an inclination/eccentricity of the rod 2.
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