Hydrodynamic shaft seal

Claim 2

In a rotary shaft seal having a radially inwardly directed sealing lip defined by converging frustoconical surfaces, the improvement comprising at least one hydrodynamic sealing element located on one of said frustoconical surfaces, said element being a triangular pad having side legs converging to an apex, said pad arranged with said apex adjacent said sealing lip, the surface of said pad between said side legs being defined by a cylindrical surface of revolution that is tangential to said one frustoconical surface, said cylindrical surface of revolution having its axis parallel to a line bisecting said pad through said apex and a radius that is less than the radius of curvature of said one frustoconical surface, said pads having zero height through their centers and at their apexes which are adjacent to said sealings lip.

Claim 3

The rotary shaft seal of claim 1, wherein the included angle between said side legs is approximately 140*.

Claim 4

The rotary shaft seal of claim 1, wherein the axis of said surface of revolution is normal to said sealing lip.

Claim 5

The rotary shaft seal of claim 1, wherein there are a plurality of sealing elements equally spaced around the circumference of said one frustoconical surface.

Claim 6

A rotary shaft seal for sealing between a housing and a relatively rotating shaft comprising an annular rigid case adapted to sealingly engage said housing, a resilient annulus bonded to said annular case, said annulus having a radially inwardly directed, circumferentially extending sealing lip defined by first and second converging surfaces, said sealing lip adapted to sealingly engage said shaft, a plurality of circumferentially spaced hydrodynamic sealing elements formed on said first converging surface, each of said elements having a pair of fluid deflection surfaces converging to an apex, said apex being adjacent said sealing lip, said apex having zero height relative to said first converging surface, and each of said fluid deflection surfaces having progressively increasing height relative to said first converging surface in moving from said apex to their respective outer ends.

Claim 7

A rotary shaft seal for sealing between a housing and a relatively rotating shaft comprising an annular rigid case adapted to sealingly engage said housing, a resilient annulus bonded to said annular case, said annulus having a radially inwardly directed, circumferentially extending sealing lip defined by first and second converging surfaces, said sealing lip adapted to sealingly engage said shaft, a plurality of circumferentially spaced hydrodynamic sealing elements formed on said first converging surface, each of said elements having a pair of fluid deflection surfaces converging to an apex, said apex being adjacent said sealing lip, said apex having zero height relative to said first converging surface, and each of said fluid deflection surfaces having progressively increasing height relative to said first converging surface in moving from said apex to their respective outer ends.

Claim 8

The rotary shaft seal of claim 5, wherein a zone of zero height relative to said first surface bisects each pair of fluid deflection surfaces and extends through said apex.

Claim 9

The rotary shaft seal of claim 6, wherein the surface between a pair of fluid deflection surfaces is defined by a cylindrical surface of revolution that is tangential with said zone of zero height, said surface of revolution having an axis parallel to said zone and a radius that is less than the radius of curvature of said first converging surface.

Claim 10

A rotary shaft seal for sealing between a housing and a relatively rotating shaft extending through said housing, comprising a rigid case adapted to sealingly engage said housing, a resilient annulus attached to said case, said annulus having a radially inwardly directed and circumferentially extending sealing lip adapted to sealingly engage said shaft, said sealing lip defined by first and second converging surfaces, a plurality of circumferentially spaced hydrodynamic sealing elements formed on said first converging surface, each of said elements comPrising a pair of fluid-deflecting ribs, said ribs of a pair arranged to converge to an apex located adjacent said sealing lip, each of said ribs having zero height relative to said first converging surface at said apex and progressively increasing relative height and mass along their length.

Claim 11

A rotary shaft seal for sealing between a housing and a relatively rotating shaft extending through said housing, comprising a rigid case adapted to sealingly engage said housing, a resilient annulus attached to said case, said annulus having a radially inwardly directed and circumferentially extending sealing lip adapted to sealingly engage said shaft, said sealing lip defined by first and second converging surfaces, a plurality of circumferentially spaced hydrodynamic sealing elements formed on said first converging surface, each of said elements comPrising a pair of fluid-deflecting ribs, said ribs of a pair arranged to converge to an apex located adjacent said sealing lip, each of said ribs having zero height relative to said first converging surface at said apex and progressively increasing relative height and mass along their length.

Claim 12

The rotary seal of claim 8, wherein said sealing lip forms a continuous, circumferentially extending first zone of contact on said shaft and said ribs are adapted to form second zones of contact contiguous with said first zone, said second zones of contact gradually tapering to zero contact in moving from said first zone of contact.