| 摘要 |
A stopper device (11) comprises: a second cylinder (12) which is formed in an end (5A) in a first cylinder (5); a second piston (13) which moves by movement of a piston rod (7) to be inserted into the second cylinder (12); and a piston ring (17) with both ends of a circumferential direction, wherein some parts of the piston rings are separated and the piston rings have ring shapes. A circumferential groove (14) is formed on an external side of the second piston wherein the circumferential groove comprises a bottom surface (14A), one side end surface (14B), and the other side end surface (14C). A first passage (19) is formed between the end sides of the piston ring (17) when the piston ring (17) comes in contact with one end side (14B) of a circumferential groove (14). Both ends of the piston ring have shaft directional contact parts (17A1, 17B1) and diametric contact parts (17A2, 17B2). |
