| 摘要 |
PROBLEM TO BE SOLVED: To secure smooth operation and stable sealing performance of a piston rod. SOLUTION: A double seal 8 composed of a rod seal 10 and an O-ring 11 for the backup of the rod seal 10 is arranged in a circular groove 7 formed on an inner periphery of a rod guide 3 which slidably guides a piston rod 2. A circular cutout 15 is formed on an outer periphery of a front end of the rod seal 10. A circular projection 18 extended from the rod guide 3 is located in the cutout 15 for partially sharing energizing force to be applied from the O ring 11 to the rod seal 11. Length L1 of the circular projection 18 exceeds axial depth L2 of the cutout 15. Even in a case where temperature rises, clearance ranging between δ and δ' is always formed between the front end of the rod seal 10 and a low pressure side seal receiving surface 3a of a rod guide 3. Maximum contact surface pressure is generated in the vicinity of a high pressure side contact limit point A. A desired sealing performance is thus secured. |
