| 摘要 |
PURPOSE:To reduce the loss of driving energy by preventing oil leak without increasing the sliding resistance between a cylinder and a piston in a ring-shaped hydraulic apparatus, and fitting a piston ring whose assembly performance is improved. CONSTITUTION:A ring-shaped hydraulic apparatus 10 is equipped with a ring- shaped cylinder 11 and a ring-shaped piston 12 which is freely fitted into the ring-shaped fitting groove of the cylinder 11, and an oil passage 13 is connected to the cylinder 11, and the pressurized working oil is supplied. A guide block 16 and a notched part 18 prevent the piston 12 to revolve with respect to the cylinder 11 through the mutual free-fitting. When a piston ring 15 is fitted, the piston 12 is fitted into the cylinder 11 with the ring 15 fitted into the groove 12a of the piston 12. When a piston ring 14 is fitted, the piston ring 14 is fitted by pushing it into the groove 11a of the cylinder 11 by utilizing the inclined surface at the edge part on the free fitting side of the piston 12. |
