Track pin assemblies and seal therefor

Claim 2

An end face seal unit for use in severe service environments, said assembly comprising, in combination, a primary annular sealing ring having a generally axially extending flange portion and a generally radially extending flange portion, said axial flange having respective inner and outer diameter surfaces and said axial flange having generally radially extending front and rear surface portions, said front surface portion of said radial flange having a portion thereof adapted to engage a mating surface in snug end face sealing engagement therewith when urged axially toward said mating surface, and a secondary sealing member of generally annular form, said secondary member including generally axially extending inner and outer diameter surfaces and front and rear surface portions, said front and rear surfaces being inclined forwardly and inwardly such that said secondary member, in the unstressed condition thereof, has a generally parallelogram shaped cross section, said inner diameter of said secondary member being received in use over said outer diameter of said axial flange portion of said primary seal ring, with at least a portion of said front surface of said secondary seal member engaging at least a portion of said rear surface of said primary seal member, said primary member being made from a relatively stiff but resilient first elastomeric material, and said secondary member being made from a second resilient elastomeric material which is substantially less stiff than said first material, said axial flange portion of said primary member being adapted to be supported in use on the inner diameter thereof by a portion of an element being sealed thereby.

Claim 3

A seal unit as defined in claim 1 in which said generally radially extending front surface of said radial flange is inclined slightly forwardly as it extends outwardly.

Claim 4

A seal unit as defined in claim 1 in which in the unstressed condition thereof, a radially inner portion of said front surface portion of said secondary member extends forwardly of the remainder of said front surface portion, and lies substantially parallel to said rear surface portion of said radial flange on said primary seal ring.

Claim 5

A seal unit as defined in claim 1 in which said inner diameter of said secondary seal member includes means at least partially defining oil passages extending axially from said front surface portion of said radial flange to the rear of said axial flange.

Claim 6

A seal unit as defined in claim 1 in which said inner diameter surface of said axial flange includes a plurality of radially inwardly directed support projections having circumferentially spaced apart inner ends, said inner ends being adapted, in use, to engage a portion of said element being sealed, whereby said inner diameter is supported against substantial radially inward movement, and whereby the spaces between said support projections define, in use, oil passages extending axially between said front surface of said radial flange and the rear surface of said axial flange.

Claim 7

A seal unit as defined in claim 5 in which said support projections are in the form of serrations, said inner ends thereof being axially extending teeth, said inner ends being adapted to be flattened into substantial circumferential engagement with said portion of said sealed element under application of a radial compressive load to said primary seal ring by said secondary member.

Claim 8

A seal unit as defined in claim 1 in which said first elastomeric material comprises a urethane elastomer.

Claim 9

A seal unit as defined in claim 1 in which said second elastomeric material comprises a nitrile rubber.

Claim 10

A seal unit as defined in claim 1 in which said secondary member, in use, is deformed under the application of an axial load to said seal such that said front and rear surfaces thereof bulge outwardly, said parallelogram shaped cross section being also distorted so that said inner and outer diameter surfaces thereof are moved toward a position of radial alignment.

Claim 11

A combination track pin and seal assembly, said assembly including a track pin, a first link portion secured to said track pin and a second link portion journaled for oscillation with respect to said pin, a bushing surrounding a portion of said pin and received within said portion of said second link, said bushing including a radially extending, axially directed end face mating surface, a seal-receiving counterbore disposed in said first link, an annular spacer element surrounding said pin and extending axially between an end face of said counterbore and said end face of said bushing, the outer diameter of said spacer, said bushing end face and said counterbore defining a seal-receiving cavity, and an end face seal unit disposed within said cavity, said unit including a primary annular sealing ring having a generally axially extending flange portion, said axial flange having respective inner and outer diameter surfaces and said axial flange having generally radially extending front and rear surface portions, said front surface portion of said radial flange having a portion thereof engaging said mating surface on said bushing in snug end face sealing engagement therewith when urged axially toward said mating surface, and a secondary sealing member of generally annular form, said secondary member including generally axially extending inner and outer diameter surfaces and front and rear surface portions, said front and rear surfaces being inclined forwardly and inwardly such that said secondary member, in the unstressed condition thereof, has a generally parallelogram shaped cross section, said inner diameter of said secondary member being received over said outer diameter of said axial flange portion of said primary seal ring, with at least a portion of said front surface of said secondary seal member engaging at least a portion of said rear surface of said primary seal member, said primary member being made from a relatively stiff but resilient first elastomeric material, and said secondary member being made from a second resilient elastomeric material which is substantially less stiff than said first material, said axial flange portion of said primary member being received over and supported on said inner diameter thereof by the outer diameter portion of said spacer.

Claim 12

A combination track pin and seal assembly, said assembly including a track pin, a first link portion secured to said track pin and a second link portion journaled for oscillation with respect to said pin, a bushing surrounding a portion of said pin and received within said portion of said second link, said bushing including a radially extending, axially directed end face mating surface, a seal-receiving counterbore disposed in said first link, an annular spacer element surrounding said pin and extending axially between an end face of said counterbore and said end face of said bushing, the outer diameter of said spacer, said bushing end face and said counterbore defining a seal-receiving cavity, and an end face seal unit disposed within said cavity, said unit including a primary annular sealing ring having a generally axially extending flange portion, said axial flange having respective inner and outer diameter surfaces and said axial flange having generally radially extending front and rear surface portions, said front surface portion of said radial flange having a portion thereof engaging said mating surface on said bushing in snug end face sealing engagement therewith when urged axially toward said mating surface, and a secondary sealing member of generally annular form, said secondary member including generally axially extending inner and outer diameter surfaces and front and rear surface portions, said front and rear surfaces being inclined forwardly and inwardly such that said secondary member, in the unstressed condition thereof, has a generally parallelogram shaped cross section, said inner diameter of said secondary member being received over said outer diameter of said axial flange portion of said primary seal ring, with at least a portion of said front surface of said secondary seal member engaging at least a portion of said rear surface of said primary seal member, said primary member being made from a relatively stiff but resilient first elastomeric material, and said secondary member being made from a second resilient elastomeric material which is substantially less stiff than said first material, said axial flange portion of said primary member being received over and supported on said inner diameter thereof by the outer diameter portion of said spacer.

Claim 13

A combination as defined in claim 10 in which, when said bushing end face engages said spacer, said secondary member is deformed under an axial load applied to said primary seal ring by said bushing end face such that said front and rear surfaces of said secondary ring bulge outwardly and said parallelogram shaped cross section of said secondary ring is distorted so that said inner and outer diameter surfaces thereof are moved toward a position of radial alignment.

Claim 14

An end face seal as defined in claim 1, wherein said front surface portion of said radial flange of said primary sealing ring comprises a first surface and a second surface, said first surface being a generally planar, radially extending surface and said second surface being joined thereto along a common edge and being of frustoconical shape, said second surface being inclined radially outwardly and toward said mating surface.

Claim 15

An end face seal as defined in claim 12, wherein the angle between said first and said second surfaces, measured exteriorly thereof, is from about 140° to about 165°.