Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
TOOL AND PROCESS FOR INSTALLING A SEAL LIP OVER A SEALING SURFACE
Document Type and Number:
WIPO Patent Application WO/2007/061991
Kind Code:
A1
Abstract:
To install an elastomeric seal (6) element having a radial lip (34) over a cylindrical sealing surface (30), the radial lip is expanded over a cylindrical exterior surface (62) on a mandrel (60) and the sealing surface is aligned with the exterior surface of the mandrel. The mandrel has axially directed grooves (66) that open out of its exterior surface, and these grooves are from within the mandrel filled with grease (g), which deposits on the radial lip where the lip traverses the grooves. Thereupon, the seal element is pushed off the mandrel and onto the aligned sealing surface.

Inventors:
GINGRICH JOHN R (US)
COOK MATTHEW (US)
KULL KENTON (US)
HENDRICKS SCOTT (US)
Application Number:
PCT/US2006/044979
Publication Date:
May 31, 2007
Filing Date:
November 20, 2006
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
TIMKEN CO (US)
GINGRICH JOHN R (US)
COOK MATTHEW (US)
KULL KENTON (US)
HENDRICKS SCOTT (US)
International Classes:
B25B27/00; F16J15/32
Foreign References:
DE4224995C11993-12-16
EP0498929A11992-08-19
GB910191A1962-11-14
US4531748A1985-07-30
Attorney, Agent or Firm:
BOESCHENSTEIN, Edward, A. (Lieder Woodruff & Lucchesi, L.C., 12412 Powerscourt Drive, Suite 20, St. Louis Missouri, US)
Download PDF:
Claims:

Claims:

1. In combination with a circular sealing surface and with a seal lip that is configured to fit around the sealing surface and establish a fluid barrier along it, a tool for expanding the radial lip to enable it to fit over the sealing surface and for lubricating the lip, said tool comprising: a mandrel having a circular exterior surface that generally aligns with the sealing surface, the circular surface of the mandrel having a diameter great enough to hold the radial lip in an expanded condition, the mandrel having depressions that open out of its circular exterior surface; and a lubricant in the depressions of the mandrel.

2. The combination according to Claim 1 wherein the sealing surface is cylindrical.

3. The combination according to Claim 2 wherein the sealing surface is on an axial wall around which the radial lip fits, and the axial wall forms part of a generally rigid shield for a seal.

4. The combination according to Claim 3 wherein the seal also includes a generally rigid case and the radial lip is part of an elastomeric seal element that is bonded to the case. 5. The combination according to Claim 4 wherein the shield initially has an axial extension that extends from its axial wall, and the axial extension temporarily engages the mandrel to bring the sealing surface into alignment with the exterior surface of the mandrel.

6. The combination according to Claim 5 wherein the mandrel has a rabbet over which the axial extension on the shield fits.

7. The combination according to Claim 1 wherein the exterior surface of the mandrel is cylindrical.

8. The combination according to Claim 7 wherein the depressions are axially directed grooves.

9. The combination according to Claim 1 wherein the mandrel has an internal cavity and ports that lead from the cavity to the depressions.

10. A process for installing a radial seal lip over a circular sealing surface, said process comprising: expanding the radial lip over a circular exterior surface on a mandrel having depressions that open out of the exterior surface; aligning the sealing surface with the exterior surface of the mandrel; introducing a lubricant into the depressions of the mandrel with some of the lubricant being beyond the exterior surface of the mandrel; and while the lubricant is in and beyond the depressions, moving the radial lip off the mandrel and onto the sealing surface, whereby the lip moves onto the sealing surface well lubricated.

11. The process according to Claim 10 wherein the lubricant is introduced into the depressions from within the mandrel.

12. The process according to Claim 11 wherein the mandrel has an internal cavity and ports leading from the cavity to the depressions, and the lubricant is introduced into the depressions by forcing it from the cavity through the ports.

13. The process according to Claim 10 wherein the sealing surface lies along an axially directed wall and the sealing surface is aligned with the exterior surface of the mandrel by engaging the axial wall with the mandrel.

14. The process according to Claim 13 wherein the exterior surface of the mandrel is cylindrical.

15. The process according to Claim 10 wherein the depressions are axially directed grooves. 16. In combination with a rigid shield having an axially directed wall along which a cylindrical sealing surface lies and with a flexible seal

element and rigid seal case to which the seal element is bonded, with the seal element having a radial lip that terminates at a sealing edge which has a lesser diameter than the sealing surface when the radial lip is unrestrained, a tool for installing the seal case and seal element on the shield so as to provide a seal, said tool comprising a mandrel having a cylindrical exterior surface that aligns with the cylindrical sealing surface around which the seal element and case fit, the diameter of the exterior surface being greater than the diameter of the sealing edge so that the radial lip is expanded around the exterior surface, the mandrel having depressions that open out of its exterior, a cavity in its interior, and ports connecting the cavity with the depressions; and a lubricant in the cavity, ports and depressions of the mandrel. 17. The combination according to Claim 16 wherein the shield is temporarily engaged with the shield.

18. The combination according to Claim 16 wherein the depressions are axially directed grooves.

Description:

TOOL AND PROCESS FOR INSTALLING A SEAL LIP OVER A SEALING SURFACE

Cross-Reference to Related Applications This application derives and claims priority from U.S. provisional application 60/738,460, filed 21 November, 2005, which is incorporated herein by reference. Technical Field

This invention relates in general to seals and, more particularly, to a tool and process for installing a seal lip over a sealing surface. Background Art

Seals find widespread use in mechanical equipment to isolate cavities that exist between moving components. For example, where a hub spindle rotates in a housing on a bearing located between them as in a so-called wheel end, seals exist between the housing and spindle to retain lubricants within the bearing and to isolate the lubricants and bearing from external contaminants such as water and dirt. Often the seals themselves are packaged components, each consisting of a case, a shield generally within the case, and an elastomeric element bonded to the case and having at least one lip that contacts a sealing surface along the shield to establish a live or dynamic fluid barrier. Sometimes the seals are assembled without adequate lubrication, and once placed in service produce a squeaking or chirpy noise until the lubricant from the bearing works between seal lip and the sealing surface on the shield. The typical procedure for assembling such a seal involves applying multiple dots of grease to the radial lip of the seal. Then the radial lip is forced over a mandrel, which expands the lip enough to enable it to pass over the sealing surface of the shield. This disturbs the grease and indeed removes much of it from the lip. Next, the shield is positioned adjacent to the mandrel with its sealing surface aligned with the mandrel surface around which the expanded lip fits. Thereupon, the seal case is pushed toward the shield so that the expanded lip moves off

the surface of the mandrel and onto the sealing surface of the shield. Afterwards, the end of the shield may be upset to capture the case and lip between the ends of the shield and thereby unitize the seal. Brief Description of the Drawings In the accompanying drawings which form part of the specification:

Fig. 1 is a longitudinal sectional view showing a tool for installing a seal over a sealing surface as well as the seal itself, all in accordance with the present invention; Fig. 2 is a transverse sectional view of the tool;

Fig. 3 is a longitudinal section view of a conventional (prior art) tool for installing the seal;

Fig. 4 is a partial sectional view of the seal; and

Fig. 5 is a partial sectional view of the seal showing its lips undeflected, but nevertheless showing in broken lines the shield that would normally deflect the lips, with the shield being open.

Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. Best Mode for Carryinci out the Invention Referring now to the drawings, an installation tool A (Figs. 1 and

2) serves to facilitate the assembly of a seal B with enough lubricant in the seal B to enable it to operate quietly from the very outset, that is to say, without emitting a squeaking or chirpy noise. The tool A represents a significant improvement over a conventional tool C (Fig. 3) currently employed to assemble the seal B.

To understand the tools A and C requires a knowledge of the seal B. It basically has (Figs. 4 and 5) three components: a seal case 2, a shield 4, and an elastomeric seal element 6 that is bonded to the case 2 and bears against the shield 4. The seal B establishes a live or dynamic fluid barrier between the seal element 6 and case 2 when one rotates relative to the other about an axis X.

Typically the case 2 fits into a housing 8, while the shield 4 fits over a component 10 that rotates in the housing 8 by reason of an antifriction bearing. The component 10 may be the inner race of the antifriction bearing or a shaft over which the inner race fits. The housing 8 may be bolted against a suspension upright of an automotive vehicle, while the shaft may form the spindle of a hub that rotates in housing 8. The whole assembly is commonly referred to as a wheel end. See U.S. patent 6,637,943, which is incorporated herein by reference, for a typical location for the seal B in a wheel end. Then again, the housing 8 may rotate around the component 10, as in many nondriven wheels of automotive vehicles. However, the seal B is not confined to automotive vehicles, but has uses in other mechanical equipment having housings and shafts, irrespective of which rotates relative to the other.

The seal case 2 preferably takes the form of a metal stamping having an axial wall 16 and a radial wall 18. As such, it is relatively rigid and of fixed shape. The axial wall 16 fits into the housing 8 with an interference fit and thereby establishes a static fluid barrier with the housing 8. The radial wall 18 turns inwardly from one end of the axial wall 16 and thus projects toward the axis X. It lies perpendicular to the axis X.

The shield 4 likewise takes the form of a metal stamping and is thus relatively rigid and fixed in shape. It has an axial wall 20, a radial wall 22 at one end of the axial wall 20, and a shorter retaining curl 24 at the other end. The axial wall 20 lies within and is generally surrounded by the seal case 2. It fits over the component 10 with an interference fit and thus establishes a static fluid barrier with the component 10. The radial wall 22 projects outwardly from one end of the axial wall 20 toward the free end of the axial wall 16 for the case 2 and thus is spaced from the radial wall 18 of the case 2. The curl 24 turns outwardly from the opposite end of the axial wall 20 at a radius 26 and lies slightly beyond the radial wall 18 of the case 2 and beyond the seal element 6. Both the

radial wall 22 and the lip 24 lie perpendicular to the axis X. Between the radius 26 and the radial wall 22 the axial wall 20 of the shield 4 provides a cylindrical sealing surface 30 that is presented outwardly away from the axis X. The thickness of the curl 24 itself and the radius 26 at which it merges into the axial wall 20 is somewhat less than the thickness of the axial wall 20 and radial wall 22. This enables the curl 24 to undergo a deformation at its radius 26 so as to change from an axial orientation to a radial orientation. In this regard, prior to assembly of the seal B, the shield 4 has an open configuration in which the curl 24 and radius 26 exist as an axial extension 32 (Fig. 5) of the axial wall 20, although of a lesser thickness.

The seal element 6 is molded from an elastomer and thus has a good measure of flexibility. It is bonded to seal case 2 along the inside surface of the axial wall 16 and radial wall 18 of the case 2 and also along the end edge of the radial wall 18. Here it projects inwardly beyond the peripheral margin of the curl 24 and takes the form of a radial lip 34 having a sealing edge 36. Behind the edge 36 the lip 34 has an annular groove 38 that opens away from the axis X, and it contains a garter spring 40. The radial lip 34 at its sealing edge 34 bears against the sealing surface 30 on the axial wall 20 of the shield 4 and here establishes a dynamic fluid barrier. However, when the lip 34 is unrestrained, its sealing edge 36 possesses a diameter less than the diameter of the cylindrical sealing surface 30 on the axial wall 20 of the shield 4 (Fig. 5). The garter spring 40 biases the lip 34 and its sealing edge 36 to this contracted configuration.

The seal element 6 also has an axial lip 42 that lies outwardly beyond the radial lip 34 and projects obliquely away from the radial wall 18 of the case 2. It terminates at a sealing edge 44 that bears against the inside face of the radial wall 22 for the shield 4. When the axial lip 42 is unrestrained, its sealing edge 44 will lie beyond the plane normally

occupied by the inside face of the radial wall 22 on the shield 4. Thus, by reason of its own resiliency, the axial lip 42 at its sealing edge 44 is biased against the radial wall 22 of the shield 4.

The conventional procedure for uniting the seal case 2 with the seal element 6 bonded to it and the shield 4 relies on the tool C (Fig. 3). It includes a mandrel 50 having a smooth and uninterrupted cylindrical surface 52 and a rabbet 54 at the end of the surface 52. The diameter of the cylindrical surface 52 corresponds to the outside diameter of the axial extension 32 on the open shield 4. The diameter of the rabbet 54 corresponds to the inside diameter of the extension 32. In addition, the procedure utilizes an annular pusher 56 that fits around the mandrel 50 and has a leading face that conforms to the back of the seal element 6 and seal case 2.

To install the united seal case 2 and seal element 4 on the shield 4 with the tool C, dots of grease are placed along the radial lip 34 of the seal element 6 at its sealing edge 36. Then the seal element 6 is forced over the cylindrical surface 52 of the mandrel 50. This expands the radial lip 34, but it also dislodges the grease from the sealing edge 36 and other surfaces where it should exist. With the seal element 6 and seal case 2 so disposed, the open shield 4 is aligned with the mandrel 50, the axial extension 32 of the former being fitted into the rabbet 54 of the latter. Thereupon, the pusher 56 is advanced and it drives the seal element 6 and seal case 2 off the mandrel 50 and onto the sealing surface 30 on the axial wall 20 of the shield 4, but sometimes with a loss of grease. The absence of adequate grease results in a squeaking or chirpy sound when the shield 4 is rotated in the case 2 and seal element 6 after they have been installed over the shaft 10 and in the housing 8, respectively.

The improved installation tool B (Figs. 1 and 2) includes a mandrel 60 having a cylindrical exterior surface 62 and a rabbet 64 at the end of the surface 62. The mandrel 60 has axially directed grooves

66 that open out of its exterior surface 62 and lead out to the rabbet 64. In addition, the mandrel 60 has a center cavity 68 in the form of a bore and radially directed ports 70 that lead from the cavity 68 to the grooves 66, there being separate port 70 for each groove 66. The cavity 68, ports 70, and grooves 66 contain a lubricant, preferably in the form of grease g..

The diameter of the cylindrical surface 62 corresponds to the outside diameter of the axial extension 32 on the open shield 4. The diameter of rabbet 64 is slightly smaller than the inside diameter of the axial extension 32. This enables the open shield 4 at its axial extension 32 fit over the rabbet 64 with the outside surface of the extension 32 aligned and flush with the cylindrical surface 62.

Apart from the mandrel 60, the tool B includes an annular pusher 72 having an inside cylindrical surface 74, the diameter of which is slightly greater than the cylindrical surface 62 of the mandrel 60. Indeed, the pusher 72 fits around the mandrel 60 with its inside surface 74 along the exterior surface 62 of the mandrel 60. The pusher 72 also has a front face 76 that conforms to the back of the united seal case 2 and seal element 6. As such it takes the form of a wedge 78 immediately outwardly from the cylindrical inside surface 74, with the wedge 78 being configured to fit against the obliquely directed radial lip 34 of the seal element 6.

To install the united seal case 2 and seal element 6 over the shield 4, with the tool A, the seal element 6 and seal case 2 to which it is bonded are aligned with the mandrel 60, and the radial lip 34 is expanded and pushed over the cylindrical surface 62 on the mandrel 60. Thereupon grease is applied to the inside face of the radial wall 22 on the open shield 4, and the open seal case 4 at its axial extension 32 is fitted into the rabbet 64 at the end of the mandrel 60. With grease g fully occupying the center cavity 68 and the ports 70 and grooves 66 of the mandrel 60, a metered quantity of grease g is forced into the center

cavity 68, and it displaces a like quantity of grease g from the ports 70 into the grooves 66. The displaced grease g overfills the grooves 66 so that grease g at the grooves 66 lies beyond the cylindrical surface 52. Some of the grease g may flow from the axial grooves 66 onto the expanded radial lip 34 of the seal element 6, depositing dots or short strips of grease g on the sealing edge 36 and surfaces leading to the sealing edge 36.

Thereafter, the pusher 72 is advanced over the mandrel 60. Its wedge 78 fits underneath the radial lip 24 and allows its front face 76 to bear uniformly against the radial lip 34 and the radial wall 18 of the case 2. The radial lip 34 slides off the cylindrical surface 62 of the mandrel 60, picking up more grease from the segments of the grooves 66 ahead of it. The radial lip 34, well lubricated, moves onto the axial extension 28 of the open shield 4 and then onto the sealing surface 30 on the axial wall 20 of the shield 4, undergoing a slight expansion at the transition between the axial extension 32 and the axial wall 20, and of course the remainder of the seal element 6 and the case 2 advance with the lip 34. Further advancement brings the sealing edge 44 of the axial lip 42 against the greased radial wall 22 of the shield 4, and the axial lip 42 deflects outwardly against the radial wall 22.

Once the case 2 and seal element 6 assume the correct axial position around the shield 4, the shield 4 and the case 2 and seal element 6 that are around the shield 4 are withdrawn from the mandrel 60. Finally, the axial extension 32 is deformed outwardly to transform it into the retaining curl 24. Thus, seal element 6 is captured between the radial wall 22 and retaining curl 24 of the shield 4, thereby unitizing the seal case 2, the shield 4 and seal element 6. The unitized seal B, well lubricated, is available for installation in the housing 8 and around the component 10.

The tool A eliminates the application of grease to the seal lip 34 at a separate station, and further provides the lip 34 with grease g that remains as the lip 34 is advanced onto the axial wall 20 of the shield 4.

The cylindrical sealing surface 30 need not be on a shield. Indeed, it may be on any circular surface against which the radial seal lip 34 works. In lieu of the grooves 66, the mandrel 60 may be provided with depressions of other configurations. Neither the sealing surface 30 nor the exterior surface 62 of the mandrel 60 need be truly cylindrical., but could be tapered.