Low friction unitized seal

A unitized seal for installation in an annular space between an inner and outer, relatively rotatable, generally coaxial members that are subject to dynamic running forces that rapidly vary the relative axial and radial positions thereof, said seal comprising,

• an inner casing of rigid material adapted to be joined to said inner rotatable member within said annular space and having a pair of radially spaced cylindrical sealing walls joined by an annular web,
• an outer casing adapted to be joined to said outer rotatable member with an annular boss located at a diameter intermediate said sealing walls and bordered by a sloped shoulder on the outside and a flared rim on the inside,
• an annular disk of relatively stiff, low friction plastic material having a flat central section and a radial width measured between inner and outer edges thereof that is slightly greater than the radial spacing of said sealing walls, said disk central section being secured to said annular boss so as to be coaxial to said inner casing and axially spaced from said annular web with said inner and outer edges contacting said sealing walls and overlaying said flared rim and sloped shoulder respectively, thereby providing two low friction lines of sealing contact, and,
• a resilient elastomer seal joined to said second casing and located in the axial space between said annular disk and annular web, said elastomer seal having at least one flexible seal lip resiliently engaged with said disk central section, thereby providing an additional low friction sealing barrier that responds quickly to said dynamic forces to maintain sealing contact,
• whereby multiple low friction sealing barriers are created within said annular space, each involving contact of compatible sealing materials, with said disk inner and outer edges being protected, in the event of radial displacement of said casings, by contact of said inner casing sealing walls with said outer casing sloped shoulder and flared rim.