| 摘要 |
PROBLEM TO BE SOLVED: To remove occurrence of a hydraulic oil leak by preventing occurrence of a friction trace at a part of sliding contact of a division wall member with a feeding and draining oil pipe and thereby preventing damage of a sealing material interposed in between them. SOLUTION: An interior of a cylinder tube 2 is partitioned into an oil chamber 14 on an opposite-of-rod side and an oil chamber 15 on a rod side by a hollow piston 3 which is attached to a base end of a hollow piston rod 4 with a division wall member 6 in between. The opposite-of-rod side and rod side oil chambers 14 and 15 are conducted into the interior of the hollow piston rod 4 by communication holes 16 and 19 and by feeding and draining oil pipes 20 and 21 which are provided in the division wall member 6. Supplying and draining of hydraulic oil are performed through the feeding/draining oil pipes 20 and 21. In such a hydraulic cylinder 1, bearing parts 22 and 23 and sealing materials 24 and 25 are axially interposed side by side between the communication holes 16 and 19 and feeding/draining oil pipes 20 and 21 which are provided in the division wall member 6, and in the direction from the aperture for holding the bearing parts 22 and 23 to the aperture for holding the sealing materials 24 and 25 from both sides, each aperture is set wider in sequence.
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