Patent ID: 9074688
Filing Date: 2015-07-07
Classification: F16J

Abstract:
1. A rotary shaft seal, comprising: first and second seals each having a fixed flat portion and a curved wall portion arranged so as to be curved in opposite directions along a shaft center, said curved wall portions of said first and second seals forming an intermediate empty space adapted to contain grease; a single circumferential groove formed in each of the respective curved wall portions of the first and second seals, said single circumferential groove forming thin portions in each of the first and second seals, said thin portions forming at least part of a wall enclosing said intermediate empty space and being thinner than a portion of said seals not enclosing said intermediate empty space, wherein said intermediate empty space is surrounded by the first and second seals and an outer circumferential surface of a rotary shaft under use conditions, and neither the single circumferential groove nor other part of the first and second seals provides a passage through which said intermediate empty space can communicate with a part of the wall not enclosing said intermediate empty space; a pair of cases between which the first and second seals are sandwiched, each of said cases of said pair of cases having an inner collar portion with an inner circumferential end portion at an end thereof closest to the shaft center, wherein each of said circumferential end portions is aligned with a part of the thin portions of the first and second seals in a direction parallel to said shaft center; and a flat ring-shaped gasket interposed between said fixed flat portions of said first and second seals.