US 8,708,343 B2Granted

Seal device

AssigneeEagle Industry Co., Ltd.

InventorsHiroshi Ebihara, Yasuhisa Arita, Yasuhiro Ikeda

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Abstract

A seal device where a seal lip reliably maintains shaft sealing relative to high-pressure fluid that is to be sealed and where the equivalent Mises stress occurring in the seal lip is reduced to extend the durable term of the seal lip longer. A backup ring has a tapered section continuously extending from a fixation section of the backup ring and also has a forward end section. A rounded surface (E) with a curvature radius (R-1) is formed at least at a boundary where a surface (D) of the tapered section changes to a surface (F) of the forward end section. A portion of the surface (D) of the tapered surface, which portion is in contact with the rounded surface (E) at the boundary, is a projected curvature surface having a curvature radius greater than the curvature radius (R-1) of the boundary.

Claims6

Dependent claims

A seal device having a backup ring protruding towards a fluid storage chamber so as to enclose a rotating shaft, wherein at least said backup ring has a tapered shape, and a distal end of a seal lip supported by the backup ring is capable of coming into contact with the rotating shaft;

said seal device characterized in that:
said backup ring has a protruding part, a tapered part and a distal end part extending continuously from a fixed part thereof;
a rounded surface having a curvature radius (R-1) is formed at least in a first boundary where a surface of said tapered part changes to a surface of said distal end;
and a rounded surface having a curvature radius (R-3) is formed in a second boundary where a surface of said protruding part changes to a surface of said tapered part;
and the surface of said tapered part is a convex surface having a substantially constant curvature radius (R-2) greater than the curvature radius (R-1) of said first boundary;
and the curvature radius (R-2) of said tapered part is the same curvature radius as the curvature radius (R-3) of said second boundary.

3 more elements

Dependencies are inferred from the claim text.