| 摘要 |
PROBLEM TO BE SOLVED: To secure the smooth movement of a moving body while maintaining the appropriate seal function without being filled with the pressure fluid by forming a pressure vent passage for discharging the pressure between a seal and a buck-up inside of a seal groove in one of moving bodies. SOLUTION: A pressure vent passage 32 communicating with a seal groove 24 formed in a cap 11 is continued to a fitting clearance 33 between the cap 11 and a valve body 1, and the fitting clearance 33 communicates with a flow-in/out port 2 side. Pressure fluid filled in a space between a seal 25 and a buck-up 26 is discharged from the pressure vent passage 32 to the flow-in/out port 2 side through the fitting clearance 33. Since the pressure fluid inside of the space is discharged, pressure dose not rise. Since the pressure inside of the space dose not rise, excessive friction of the seal 25 is not generated, and the pushing force of the buck-up 26 is restricted. The seal structure is used for a counter balance valve so as to prevent the hindering of the load holding ability. |
