| 摘要 |
PROBLEM TO BE SOLVED: To provide a sealing device which can set a surface pressure gradient to a seal ring in surface contact with a mating surface, can suppress the leakage of positive pressure to a pressure accumulation side via a pressure accumulation release passage, and can thereby improve sealing performance.SOLUTION: Since step parts are formed in opposing faces of a seal ring and a back ring, and a crush margin of the back ring with respect to the seal ring is set to be larger at a positive pressure side than at a pressure accumulation side with the step parts as a boundary, a surface pressure gradient is achieved in which the contact surface pressure of the seal ring with respect to the mating surface is small at the pressure accumulation side and large at the positive pressure side. Furthermore, since a pressure accumulation release passage is formed of a first slit, an inter-step part space, a second slit and a third slit, and the first slit is opened at a pressure accumulation side end face of the back ring and does not reach the step parts, the communication between the first slit and the inter-step part space is broken or achieved in accordance with a change of an axial position of the back ring with respect to the seal ring. |
