| 摘要 |
PROBLEM TO BE SOLVED: To provide a suspension device preventing leakage of oil from a hydraulic cylinder. SOLUTION: A pilot check valve 42 is provided on a hydraulic cylinder 2 side of a connection passage 40 to connect the hydraulic cylinder 2 to a supply/discharge control valve 10. The pilot check valve 42 is connected to the supply/discharge control valve 10 via a double-walled pipe 41 consisting of an inner cylinder and an outer cylinder, the inner cylinder forms a cylinder side supply/discharge passage 74a to pass oil to be supplied/discharged to/from the hydraulic cylinder 2, and a space between the inner cylinder and the outer cylinder forms a double-walled pipe pilot passage 91 for the pilot check valve 42. When the double-walled pipe 41 is broken by a flying stone or the like, the pressure in the double-walled pipe pilot passage 91 is dropped by the leakage of oil caused by breakage of the double-walled pipe pilot passage 91, and the pilot check valve 42 is closed. Thus, even if the breakage of the double-walled pipe 41 is further advanced, and the inner cylinder 89 is broken, leakage of oil in the hydraulic cylinder through a broken part is avoided. COPYRIGHT: (C)2006,JPO&NCIPI
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