Lip seal separating oil and grease
AssigneeThe Timken Company
InventorsEdward S. Czekansky, Dennis L. Otto
Life of this patent
Estimating the term…
Abstract
A hub rotates around the end of an axle housing on a tapered roller bearing which is packed with grease. The axle housing, which is part of a drive axle, conveys lubricating oil to the interior of the hub, but the oil does not encounter the grease, for a seal, which is fitted into the end of the bearing, separates the oil from the grease. The seal pumps the grease back to the interior of the bearing and the oil away from the interior of the bearing.
Claims24
In combination with a first machine component and a second machine component that has a hollow interior which receives the first machine component and further contains a lubricant in the form of oil, and with an antifriction bearing for enabling one of the machine components to rotate relative to the other machine component, the bearing having an inner race located around the first machine component, an outer race within the second machine component and encircling the inner race such that an annular space exists between the races to form the interior of the bearing, and rolling elements arranged in a circular row between the races, the annular space of the bearing containing a lubricant in the form of grease, sealing surfaces carried by at least one of the components and located within the hollow interior of the second component, a seal for isolating the grease within the annular space of the bearing from the oil in the hollow interior of the second component, said seal comprising:
- a first seal lip in the form of a labyrinth carried by one of the components and establishing a dynamic fluid barrier along one of the sealing surfaces that is carried by the other component, the first seal lip being spaced slightly from the one sealing surface and being exposed to the annular space between the races and to the grease in that annular space, the first lip being configured to pump grease which encounters it back toward the annular space;
- a second lip carried by one of the components and contacting a sealing surface carried by the other component to form another dynamic fluid barrier beyond the first lip, so that the first lip is located between the annular space between the races and the second lip, the second lip being exposed through the space between the first lip and its sealing surface to the annular space between the races, so that a small amount of grease will migrate to the second lip on occasion;
- and a third lip carried by one of the components and contacting a sealing surface to form still another dynamic fluid barrier beyond the second lip, so that the second lip is interposed between the first and third lips, the third lip being exposed to the oil in the interior of the second machine component, at least the second and third lips being formed from an elastomeric material.
In combination with outer and inner machine components, one of which rotates relative to the other, the machine components defining an enclosed annular space which contains oil and grease, a seal located in the annular space for separating the oil and the grease, said seal comprising:
- an outer case of annular configuration fitted to the outer machine component, an inner case of annular configuration fitted to the inner machine component and located generally within the outer case, at least one case having a sealing surface presented toward the other case;
- a first seal lip on one of the cases and extended along the sealing surface of the other case, the first lip being exposed to the grease at one end of the seal and being configured to pump the grease that encounters it at the sealing surface away from that end of the seal when relative rotation occurs between the cases;
- and a second lip located on one of the cases and extending along and contacting the sealing surface of the other case, the second lip being configured to pump oil in the direction opposite to that in which the grease is pumped when relative rotation occurs between the cases.
In combination with an axle housing having a hollow interior that is in communication with a source of lubricating oil, and with a hub that has a hollow interior which receives the axle housing and is in communication with the hollow interior of the axle housing so that oil flows from the interior of the axle housing into the interior of the hub, and with a bearing that enables the hub to rotate on the axle housing about an axis of rotation, the bearing including an outer race located in the hollow interior of the hub, an inner race located on the axle housing, and rolling elements located in a circular row between the races and rolling along the races when the hub revolves about the axle housing, the rolling elements separating the races so that the bearing has an annular interior, the annular interior containing grease, the hub and the axle housing each carrying a mounting surface;
- a seal for isolating the grease within the interior of the bearing from the oil within the interior of the hub, said seal comprising:
- a first case fitted to one of the mounting surfaces such that a static seal exists between the case and mounting surface, the first case providing an axially directed sealing surface;
- a second case fitted to the other mounting surface such that a static seal exists between the second case and other mounting surface;
- a first seal lip in the form of a labyrinth attached to the first case and located along the sealing surface of the second case where it establishes a dynamic fluid barrier, yet is spaced slightly from that sealing surface, the first lip confronting the interior of the bearing such that it is exposed to the grease;
- an elastomeric second lip attached to the first case and having an edge along which it contacts the sealing surface of the second case to establish a dynamic fluid barrier beyond the first lip, so that the first lip is interposed between the second lip and the interior of the bearing, the second lip being exposed to the interior of the bearing through the space between the first lip and the sealing surface, so that a small amount of grease will migrate to the second lip on occasion and lubricate the edge where the second lip contacts the sealing surface;
- and an elastomeric third lip on one of the cases and contacting the other case, the third lip being located beyond the second lip and confronting the interior of the hub where it is exposed to the oil, the third lip establishing a dynamic fluid barrier which retards the advancement of oil toward the second lip.
Dependencies are inferred from the claim text.