Importance

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Abstract

A radial lip seal (10) having a sealing lip (16) made of first and second materials arranged in alternating regions (20,22) and forming a continuous contact band. The seal is a rotational seal for contacting a shaft or sleeve in a relatively rotatable relationship. The first and second materials have differing physical characteristics to increase hydrodynamic activity at the sealing lip (16). The first material may be a polytetrafluoroethylene material and the second material disclosed may be silicone, fluoroelastomer, nitrile, ethylene acrylic or polyacrylate elastomers. The boundaries (42) between the first and second materials at the contact band preferably intersect the circumferentially extending contact band at an angle. A method of making a radial lip seal is also disclosed wherein an annular wafer (32) of a first material having an undulating circumferential edge (34) with spaced radially recessed portions (36) is placed in a mold (44). A ring (45) of elastomeric material is placed in the mold (44) with the wafer (32). The radial lip seal (10) is then formed by molding the ring (45) of elastomeric material and wafer (32) into the desired seal configuration. The process is completed by forming the sealing lip (16) by cutting the molded wafer (32) and molded elastomeric material contained in the recesses (36) of the wafer (32).

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First Claim