Bidirectional hydrodynamic shaft seal

Claim 2

A shaft seal comprising a molded sealing ring of resilient material having a peripheral sealing lip with inner and outer mutually convergent, generally frustoconical surfaces respectively facing towards and away from the fluid-sealing side of the seal, a continuous circumferential sealing band co-axial with said ring and defined by the convergence of said frustoconical surfaces, said outer frustoconical surface having a plurality of hydrodynamic flutes, each flute being continuous and tangentially meeting said sealing band once only and tangentially leaving it once only, said flutes crossing each other, with their points of tangency being evenly spaced around said sealing band, said flutes being operative when the shaft is rotating relative to the seal in either direction to sweep back to said sealing band fluid that leaks past said sealing band.

Claim 3

The shaft seal of claim 1 wherein there is in addition at least one more continuous flute parallel to and spaced axially from each said continuous flute and having a larger diameter, so that as the sealing band wears, said one more flute becomes hydrodynamically active in place of the former flute and whereby there is a plurality of groups of parallel said flutes, with their actual and prospective points of tangency evenly spaced around said sealing band.

Claim 4

A bidirectional hydrodynamic shaft seal comprising, a rigid annular member, and a molded sealing member of elastomeric material supported by and bonded to said rigid annular member, said sealing member having a primary sealing lip for making circular contact with a shaft rotating relatively to said lip, said lip having a side that faces the liquid to be sealed and an air side that faces away from the sealed fluid, said air side having a generally frustoconical approach surface and having therein a plurality of continuous dynamic flutes projecting from said surface and spaced axially from each other and transversely oblique to the plane of said primary lip, a plurality of said dynamic flutes each meeting and leaving said lip tangentially at one single locus of tangency to provide hydrodynamic actiOn when the seal is mounted on a rotating shaft, whichever is the direction of rotation.

Claim 5

A bidirectional hydrodynamic shaft seal comprising, a rigid annular member, and a molded sealing member of elastomeric material supported by and bonded to said rigid annular member, said sealing member having a primary sealing lip for making circular contact with a shaft rotating relatively to said lip, said lip having a side that faces the liquid to be sealed and an air side that faces away from the sealed fluid, said air side having a generally frustoconical approach surface and having therein a plurality of continuous dynamic flutes projecting from said surface and spaced axially from each other and transversely oblique to the plane of said primary lip, a plurality of said dynamic flutes each meeting and leaving said lip tangentially at one single locus of tangency to provide hydrodynamic actiOn when the seal is mounted on a rotating shaft, whichever is the direction of rotation.

Claim 6

The seal of claim 3 wherein each dynamic flute is accompanied by at least one parallel flute of somewhat larger diameter to become active as the seal wears.

Claim 7

The shaft seal of claim 3 wherein each said dynamic flute provides a frustoconical surface inclined to the plane of said primary lip at an angle of 3* to 7* and meeting said approach surface at an obtuse angle, the portion of each said dynamic flute that tangentially meets and leaves said lip coming into contact with the shaft and cooperating therewith and with said approach surface to define a wedge that traps leaked oil and returns it across said lip.

Claim 8

The shaft seal of claim 5 wherein each said flute is about 0.010 to 0.020 inch wide.

Claim 9

A shaft seal comprising a molded sealing ring of resilient material having a peripheral sealing lip with inner and outer mutually convergent, generally frustoconical surfaces respectively facing towards and away from the fluid sealing side of the seal, a continuous circumferential sealing band co-axial with said ring defined on said lip by the convergence of said frustoconical surfaces, said outer frustoconical surface having a continuous static flute parallel to and spaced from said sealing band and a plurality of continuous hydrodynamic flutes, each tangentially meeting said static flute and tangentially leaving it, at a single locus of tangency with their respective points of tangency evenly spaced around said static flute, said static flute having its inner diameter no smaller than the smallest inner diameter of said hydrodynamic flute, said hydrodynamic flutes being operative when the shaft is rotating relative to the seal in either direction to sweep back to said sealing band fluid that leaks past said sealing band.

Claim 10

A shaft seal comprising a molded sealing ring of resilient material having a peripheral sealing lip with inner and outer mutually convergent, generally frustoconical surfaces respectively facing towards and away from the fluid sealing side of the seal, a continuous circumferential sealing band co-axial with said ring defined on said lip by the convergence of said frustoconical surfaces, said outer frustoconical surface having a continuous static flute parallel to and spaced from said sealing band and a plurality of continuous hydrodynamic flutes, each tangentially meeting said static flute and tangentially leaving it, at a single locus of tangency with their respective points of tangency evenly spaced around said static flute, said static flute having its inner diameter no smaller than the smallest inner diameter of said hydrodynamic flute, said hydrodynamic flutes being operative when the shaft is rotating relative to the seal in either direction to sweep back to said sealing band fluid that leaks past said sealing band.

Claim 11

The shaft seal of claim 7 wherein said static flute and said hydrodynamic flutes are identical in shape.