| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydraulic cylinder device by which a down operation is accelerated without using a complicated structure and the operation is stabilized even when an external load is applied thereto. <P>SOLUTION: The hydraulic cylinder device includes a hydraulic pump 20 and a hydraulic cylinder 7. A hydraulic circuit 100 includes a return passage 34 for returning an excess oil recovered from a first oil chamber 11A to a reservoir tank 15 during the down operation by which a rod 9 of the hydraulic cylinder 7 is retracted. One end of the return passage 34 is joined between a first check valve 41A and the first port 21A of the hydraulic pump 20. The other end of the return passage 34 is joined to the reservoir tank 15. During the down operation, a first shuttle 52A is moved to the first check valve 41A side to open the return passage 34. <P>COPYRIGHT: (C)2013,JPO&INPIT |
