Improvements in and relating to seals

Claim 2

1 . A seal for isolating a region between machine components which rotate relative to each about an axis of rotation; said seal comprising a generally rigid case, and an elastomeric sealing element bonded to the case and including a primary lip and a secondary lip spaced axially from the primary lip, the primary lip having a first face which is presented toward the axis of rotation and a second face which is oriented at an angle with respect to the first face, the primary lip having pumping cavities which open out of the first and second faces and intersect the first face at angles oblique to a plane that is perpendicular to the axis of rotation so that lubricant entering the pumping cavities will be by virtue of relative rotation between the first face and a surface that it encircles, deflected generally axially, the secondary lip projecting generally away from the primary lip so that an annular space exists between the two lips, the secondary lip also projecting generally inwardly toward which axis of rotation beyond the primary lip, with its least diameter being less than the diameter of the first face for the primary lip.

Claim 3

2 . A seal according to claim I wherein the primary lip has a third face which is also presented at an angle with respect to the first face and is presented toward the secondary lip.

Claim 4

A seal according to claim 2 wherein the secondary lip projects from the body oblique to the axis of rotation so that an increase in pressure in the annular space between the lips will cause the primary lip to lift away from a contacting sealing surface.

Claim 5

A seal according to claim 2 wherein the pumping cavities also open out of the third face of the primary lip and into the annular space between the lips, but the area of each pumping cavity at the second face is substantially larger than the area at the third face.

Claim 6

In combination with a sealing surface of circular cross-sectional configuration and a component located generally around the surface and arranged such that relative rotation about an axis of rotation may occur between the sealing surface and the component, an improved seal for isolating within the component a region that contains a lubricant, said seal comprising a generally rigid case attached to the component and an elastomeric sealing element attached to the case and including a primary lip presented toward the isolated region and a secondary lip presented away from the isolated region, the primary lip having a first face which is presented toward and encircles the sealing surface, but is spaced from the sealing surface, and a second face which is located at an angle with respect to the first face and is presented toward and exposed to the isolated region, the primary lip further having pumping cavities which open out of both the first and second faces and are defined by cavity faces that are oblique to the direction of relative rotation between the sealing surface and encircling component and oblique to the axis of rotation such that the portion of the cavity located at the second face extends further outwardly from the axis of rotation and is wider than the portion that is remote from the second face, whereby a lubricant upon entering any cavity will be pumped back toward the isolated region and directed generally outwardly away from the axis of rotation as a result of the relative rotation.

Claim 7

In combination with a sealing surface of circular cross-sectional configuration and a component located generally around the surface and arranged such that relative rotation about an axis of rotation may occur between the sealing surface and the component, an improved seal for isolating within the component a region that contains a lubricant, said seal comprising a generally rigid case attached to the component and an elastomeric sealing element attached to the case and including a primary lip presented toward the isolated region and a secondary lip presented away from the isolated region, the primary lip having a first face which is presented toward and encircles the sealing surface, but is spaced from the sealing surface, and a second face which is located at an angle with respect to the first face and is presented toward and exposed to the isolated region, the primary lip further having pumping cavities which open out of both the first and second faces and are defined by cavity faces that are oblique to the direction of relative rotation between the sealing surface and encircling component and oblique to the axis of rotation such that the portion of the cavity located at the second face extends further outwardly from the axis of rotation and is wider than the portion that is remote from the second face, whereby a lubricant upon entering any cavity will be pumped back toward the isolated region and directed generally outwardly away from the axis of rotation as a result of the relative rotation.

Claim 8

The combination according to claim 5 wherein the secondary lip contacts the sealing surface for substantially the full circumference of the sealing surface.

Claim 9

The combination according to claim 6 wherein an annular space exists between the primary lip and the secondary lip and the secondary lip is oriented generally obliquely with respect to the sealing surface such that an increase in pressure within the annular space will cause the secondary lip to lift slightly and relieve the pressure.

Claim 10

The combination according to claim 7 werein the primary lip has a third face which is spaced from the second face and is located at an angle with respect to the first face, all such that the first face extends between the second and third faces and the third face further is presented toward and along the annular space that separates the primary and secondary lips; and wherein the pumping cavities also open out of the third face at venting apertures which are considerably smaller than the area of the pumping cavities at the second face, whereby any increase in pressure within the isolated region is transmitted through the pumping cavities and vent apertures at their ends to the annular space between the primary and secondary lips.

Claim 11

The combination according to claim 8 wherein the second and third faces are parallel and the first face is cylindrical.

Claim 12

The combination according to claim 5 wherein the faces defining each pumping cavity include a pair of side faces which diverge toward the second face and are oriented at equal but opposite angles with respect to the second face.

Claim 13

The combination according to claim 10 wherein the primary lip also has a third face which is spaced from the second face, and the pumping cavities also open out of the third face at small vent apertures.

Claim 14

The combination according to claim 11 wherein the side faces of each pumping cavity are also oblique to the first face and further intersect.

Claim 15

The combination according to any one of claims 5 to 12 wherein the first face of the primary lip is for the most part spaced from the sealing surface so that a clearance exists between the first face and the sealing surface, with the mean clearance between about 0.002 and 0.044 inches.

Claim 16

In combination with a pair of machine components which are arranged such that one will rotate relative to the other about an axis of rotation, one component being hollow and the other component being received in the hollow component and having a sealing surface that is concentric to and presented away from the axis of rotation, an improved seal for isolating within the hollow component a region that contains a lubricant, said seal comprising a mount attached to the hollow component such that a static seal exists between the mount and the hollow component; a primary seal lip carried by the mount and having spaced apart inner and outer end faces, each located at an angle with respect to the sealing surface, and a circumferential face that extends between the end faces and is presented toward the sealing surface, the inner end face being presented toward and exposed to the region isolated by the seal and the outer end face being presented away from the region isolated by the seal, the circumferential face being concentric to and substantially parallel to the sealing surface, but being spaced outwardly from the sealing surface so that a clearance exists between the circumferential face and the sealing surface, the primary lip further having a plurality of pumping cavities arranged at intervals circumferentially along it, with each pumping cavity opening out of both the inner end face and the circumferential face, each pumping cavity being defined by faces including side faces which diverge toward the inner end face and are located at an angle with respect to the direction of relative rotation so that lubricant which enters the cavity will be deflected axially toward the region isolated by the seal irrespective of the direction of relative rotation, the faces of each pumping cavity further being arranged to impart a generally wedge shaped cross-sectional configuration to the cavity with at least one of the faces diverging from the axis of rotation toward the inner end face, whereby lubricant which enters the cavity will also be directed generally away from the axis of rotation under the influence of centrifugal force; and a secondary lip also carried by the mount and being axially offset from the primary lip so that an annular space exists between the two lips, the secondary lip contacting the sealing surface along the full circumference of the sealing surface and being oriented with respect to the sealing surface such that an increase in pressure within the annular space will cause the secondary lip to separate slightly from the sealing surface and vent the annular space.

Claim 17

In combination with a pair of machine components which are arranged such that one will rotate relative to the other about an axis of rotation, one component being hollow and the other component being received in the hollow component and having a sealing surface that is concentric to and presented away from the axis of rotation, an improved seal for isolating within the hollow component a region that contains a lubricant, said seal comprising a mount attached to the hollow component such that a static seal exists between the mount and the hollow component; a primary seal lip carried by the mount and having spaced apart inner and outer end faces, each located at an angle with respect to the sealing surface, and a circumferential face that extends between the end faces and is presented toward the sealing surface, the inner end face being presented toward and exposed to the region isolated by the seal and the outer end face being presented away from the region isolated by the seal, the circumferential face being concentric to and substantially parallel to the sealing surface, but being spaced outwardly from the sealing surface so that a clearance exists between the circumferential face and the sealing surface, the primary lip further having a plurality of pumping cavities arranged at intervals circumferentially along it, with each pumping cavity opening out of both the inner end face and the circumferential face, each pumping cavity being defined by faces including side faces which diverge toward the inner end face and are located at an angle with respect to the direction of relative rotation so that lubricant which enters the cavity will be deflected axially toward the region isolated by the seal irrespective of the direction of relative rotation, the faces of each pumping cavity further being arranged to impart a generally wedge shaped cross-sectional configuration to the cavity with at least one of the faces diverging from the axis of rotation toward the inner end face, whereby lubricant which enters the cavity will also be directed generally away from the axis of rotation under the influence of centrifugal force; and a secondary lip also carried by the mount and being axially offset from the primary lip so that an annular space exists between the two lips, the secondary lip contacting the sealing surface along the full circumference of the sealing surface and being oriented with respect to the sealing surface such that an increase in pressure within the annular space will cause the secondary lip to separate slightly from the sealing surface and vent the annular space.