Seal for a joint or juncture – Seal between relatively movable parts – Relatively rotatable radially extending sealing face member
Patent
1980-11-21
1982-05-25
Ward, Jr., Robert S.
Seal for a joint or juncture
Seal between relatively movable parts
Relatively rotatable radially extending sealing face member
277 92, 277 95, 277152, 305 11, F16J 1532, F16J 1538
Patent
active
043313396
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates generally to a seal assembly and, more particularly, to an end face seal assembly including an elastomeric load ring and a plastic annular sealing member having an integral sealing lip.
BACKGROUND ART
End face seals are commonly used in severe service environments to exclude external contaminants such as grit, water, and the like from joints between relatively movable members and to retain lubricants therein. One such application for seals of this type is in the pin joints in endless track chains on track-type earthmoving vehicles. Such track chains operate in extremely abrasive environments, and the track joints may be exposed to mud, dust, sand or rock at temperatures which may reach the extremes found in either the deserts or the artic regions. Such seals perform their primary sealing function under these conditions, because the sealing portions thereof are precisely formed to mate with and sealingly engage the end faces of their associated bushings and because the annular seal rings themselves are accurately positioned and maintained under a substantial axial face load by an elastomeric load ring.
In order to function successfully under these relatively severe conditions, the seal must not only possess strength, corrosion resistance, and abrasion resistance, but also must be able to withstand the shock associated with earthmoving operations, even when carried out at subzero temperatures. In addition, it is desirable to have a seal possessing a combination of the properties of sealability, seal face stability, a low coefficient of friction and stiffness to resist deformation of the seal face or sealing lip under load. Accordingly, track seals are frequently constructed from two different materials; the sealing lip portion being formed from a relatively pliable material such as polyurethane rubber. The sealing tip is then bonded to a relatively stiff support ring formed from a polycarbonate plastic material, one type of which is available commercially under the trade name Lexan.
While end face seal assemblies having two-piece annular seal rings have demonstrated improved performance over seal assemblies of earlier designs, the requirement for a functional bond exposed to the hostile environment on one side and the lubricant on the other is an inherent weakness in the assembly. Failure of the rubber/polycarbonate bond may cause seal leakage and ultimate track joint failure. Considering the fact that there are approximately two hundred such seals on a tractor, one appreciates that a seal ring failure rate of one tenth of 1.0%, i.e. one out of every one thousand may result in premature track pin joint failure and expensive and highly undesirable downtime for one out of every five vehicles.
The foregoing illustrates limitations of the known prior art. In view of the above, it would be advantageous to provide an alternative to the prior art.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention this is accomplished by providing an end face seal assembly including a one-piece plastic annular sealing member with an integral sealing lip. The sealing member possesses preselected physical properties and cooperates with an elastomeric load ring forming a seal assembly having a long life expectancy and operational effectiveness in the severe service environment of a track joint.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. It is to be expressly understood, however, that the drawings are not intended as a definition of the invention but are for the purpose of illustration only.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a vertical elevational view in cross section of a track joint embodying the end face seal assembly of the present invention;
FIG. 2 is an enlarged view of the end face seal assembly and associated members of FIG. 1 to better illustrate the details thereof; and
FIG. 3 is an enlarged view of the sea
REFERENCES:
patent: Re24478 (1958-05-01), Kilbourne
patent: 2289274 (1942-07-01), Krug
patent: 2668068 (1954-02-01), Bredemeier
patent: 2814513 (1957-11-01), Kupfert et al.
patent: 3108816 (1963-10-01), Moore
patent: 3291494 (1966-12-01), Hatch et al.
patent: 3357679 (1967-12-01), Gulick
patent: 3515393 (1970-06-01), Metcalfe
patent: 3612538 (1971-10-01), Sievenpiper
patent: 3752243 (1973-08-01), Hummer et al.
patent: 3774920 (1973-11-01), Sievenpiper
patent: 3841718 (1974-10-01), Reinsma
patent: 3878031 (1975-04-01), Dormer
patent: 3907310 (1975-09-01), Dufour
patent: 3940154 (1976-02-01), Olsson
patent: 3995868 (1976-12-01), Smith
patent: 4066269 (1978-01-01), Linne
patent: 4094516 (1978-06-01), Morley et al.
patent: 4132418 (1979-01-01), Roli
patent: 4185842 (1980-01-01), Magara
patent: 4195852 (1980-04-01), Roley et al.
Caterpillar Tractor Co.
Ward, Jr. Robert S.
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