| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic cylinder having a long stoke, which can prevent the consumption of hydraulic oil from being increased even though the outer diameter of a piston rod is increased in view of a buckling strength. SOLUTION: A hydraulic cylinder is composed of a cylinder tube 2 formed therein with an upper oil feed and discharge port 22 communicated with a cylinder upper chamber 17, a lower cylinder port 23 communicated with a cylinder lower chamber 18, and provided at its upper end with a cylinder head 3 formed therein with a head part opening 20, and at its lower end a bottom part 21, a tubular piston rod 5 provided at its lower end with a piston adapted to make close slidable contact with the bore surface of the cylinder tube 2 and having its outer surface adapted to make close slidable contact with the bore surface of the head part opening 20, and a hollow pipe 4 having its lower end part adapted to make slidable close contact with the bore surface of a piston part opening part 60 attached to the bottom cover 21 so as to communicate its bore part with a lower feed and discharge oil port 41, and its upper end part opened in the position rod 5.
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