| 摘要 |
PROBLEM TO BE SOLVED: To provide an airtight device capable of enhancing seal durability by suppressing local expansion of amplitude in groove of an O-ring. SOLUTION: The airtight device includes an O-ring made of an elastic body, and a backup ring 1 made of resin, and seals an annular clearance between a housing having an axial hole and a shaft inserted into the axial hole to relatively move with respect to the housing, wherein the backup ring 1 is provided with a first and second cut portions 11, 12 formed so as to be inclined in the same direction from respective axially oriented side surfaces 1a, 1b to a center portion in an axial direction, and a third cut portion 13 formed over a peripheral direction in the axially center portion to connect ends of the first and second cut portions 11, 12. The first and second cut portions 11, 12 are deviated and spaced from each other in an peripheral direction. An obliquely-shaped portion having a width larger than a width obtained by halving a width along the axial direction, by the third cut portion 13, the obliquely-shaped portion obliquely traversing with respect to the axial direction, is formed between the first and second cut portions 11, 12. COPYRIGHT: (C)2012,JPO&INPIT |
