WO2001053713A1

WO2001053713A1 - Bearing seal assembly

Info

Publication number: WO2001053713A1
Application number: PCT/US2001/001538
Authority: WO
Inventors: Yoshihiro Otani
Original assignee: Ami Bearings, Inc.
Priority date: 2000-01-18
Filing date: 2001-01-17
Publication date: 2001-07-26
Also published as: AU2001230957A1; WO2001053713A9

Abstract

A bearing seal assembly (19) includes a seal element (17) and a generally L-shaped slinger (16).

Description

BEARING SEAL ASSEMBLY

This application claims the benefit of U.S. Provisional Application No. 60/176,651, filed 18 January 2000.

Field of the Invention

This invention relates to a low-cost, pressure-resistant, seal having enhanced sealing characteristics for use in a non-relubricable bearing assembly.

Background of the Invention

A typical bearing assembly is designed to have an inner bearing race and an outer bearing race, which in combination define a raceway. Multiple anti-frictional bearing elements are disposed in the raceway, thus permitting relative rotational displacement of the inner and outer races. The region defined between the inner and outer races is closed by a sealing structure or seal assembly.

Various seal assembly configurations have been utilized in the prior art to isolate the interior of the bearing assembly from the ambient environment. The seal assembly should prevent contaminants from entering the raceway. Such contaminants can impede the movement of the anti-frictional bearing elements and render the bearing assembly ineffective.

In one prior art device, a seal includes, for example, two facing L-shaped, rigid sheet metal parts. The axially directed arm of each sealing part, has on its radially outer surface, a thin elastic covering layer which is scraped off over part of its axial length during assembly of the seal into the space between the bearing races. The scraped off part of the covering is stored in a groove in the interior of the adjacent bearing race. Sealing lips seal the space between the L-shaped parts.

In another prior art device, a seal for closing the radial space between two coaxial bearing races includes an approximately L-shaped metal sealing ring having sealing lips of elastic plastic material arranged on it. To prevent contamination of the first sealing lip, the outer sealing ring has an obliquely outwardly directed fling lip which is radially inward of the first sealing lip. The first sealing lip has an obliquely outwardly directed extension located radially inwardly of and extending axially outward of the first sealing lip. Plastic material resting surfaces are defined on the axial legs of both of the sealing rings. A sealing lip seals the axial space between the sealing rings.

In yet another prior art device, circumferential shoulders are formed on an inner bearing race at locations axially outward of rolling elements contained in the bearing race. Finger rings are carried on the ends of the inner race axially outward of the shoulder and each has a first circumferentially continuous flange portion which extends radially at a location axially outwardly of the outer race ring. A second flange portion extends from the first flange portion axially inward into engagement with the associated circumferential shoulder to limit axial movement of the fmger ring member during assembly and use. Carried by the outer race ring at location axially inward of each fmger ring is a seal ring have a cirumferentially continuous web which terminates in a free end portion carrying a resilient seal member. The resilient seal member has spaced terminal end portions extending into sealing engagement with the first and second flange portions of the associated finger ring. The bearing assembly is mounted in a support housing which includes surfaces aligned with the finger rings and inclined to direct particles impelled by the fmger rings in a direction away from the bearding assembly. In still another prior art bearing seal assembly, a generally L-sectioned annular sealing plate is fitted to one of the inner and outer bearing races and a generally L- sectioned annular sealing element is fitted to the other of the inner and outer bearing races so as to confront a sealing plate. The sealing plate has a radial wall and a tilted wall extending from the radial wall so as to incline inwardly thereof, and the sealing element includes a generally L-sectioned base plate provided with an elastic member. An elastic member has a side lip slidably engageable with the radial wall of the sealing plate and a radial lip slidingly engageable with a cylindrical sleeve of the sealing plate.

The bearing seals of the prior art have several limitations and disadvantages. For example, many of the seals of the prior art do not adequately withstand the high pressures associated with cleaning operations. Such cleaning operations are typical when the bearings are used on equipment that is used in the handling and preparation of food. Bearing assemblies used in such applications are routinely subjected to high pressure water jets or high-pressure steam. The high-pressure water jets or high- pressure steam are used to clean and sanitize the food handling equipment including the bearing assemblies.

Another limitation of bearing seal assemblies known in the art is that the seal between the inner race and the outer race can be quite complex, and, therefore, costly to manufacture. This is especially true where the seal must be designed to withstand high external pressures that arise, for example from high pressure washing of machinery using such bearings.

It would therefore be an advantage to have a bearing seal that is capable of withstanding high external liquid pressure. It would be an even further advantage to have a bearing that is not only capable of withstanding high external liquid pressure, but is also less complex, and therefore of lower cost, than prior art seals.

Summary of the Invention The present invention provides a non-relubricable bearing assembly that includes outer and inner bearing races defining a space therebetween in which anti-frictional elements are contained. The anti-frictional elements may include, for example, ball bearings. The bearing assembly of the present invention further includes a generally L- shaped slinger defining a first leg and a second leg, the second leg connected to the inner bearing race and the first leg adapted to be pressably moved away towards the space between the inner and outer bearing races. A seal element having a finger extension is disposed between the inner bearing race and the outer bearing race and rotatably retained in grooves located in each bearing race. The seal element thus occupies a plane between the slinger and the bearing races. The finger extension faces the slinger. The seal element and the first leg also define a containment volume. The finger extension is adapted to be deflected by movement of the first leg thus sealing the containment volume. A grease is contained within the containment volume, the grease providing a structural support against which the first leg is pressed upon deflection of the finger extension. The present invention further provides a bearing seal assembly that is of a low cost to manufacture. Because the finger extension and the seal element are integrally formed, this configuration reduces the number of required component parts as well as provides a reduction in the number of manufacturing process steps.

Description of the Drawings

Figure 1 is a cross-sectional view of an embodiment of the bearing seal made in accordance with the principles of the present invention.

Figure 2 is cross-sectional view of the bearing seat of Figure 1 shown after the slinger is engaged.

Figure 3 is an exploded view of the bearing seal of Figure 2.

Detailed Description of the Invention

In figure 1, a bearing assembly with seal made in accordance with the principles of the present invention is labeled 10. The bearing assembly 10 includes an inner race 13 and an outer race 15. The bearing assembly 10 further includes at least an anti- fiictional element 12. As shown, anti-frictional element 12 is a ball bearing, but other anti-frictional elements maybe used in the present invention. A bearing retainer 14 positions the anti-frictional element 12. A bearing seal assembly 19, includes a seal element 17, which may be comprised of a metal, and a slinger 16. The seal element 17 is frictionally restrained by the inner race 13 by, for example a pressfit. The seal element 17 is adapted to engage the outer race 15, and in one embodiment the seal element 17 is further captured in a groove 18 in the outer race 15. The slinger 16 is a generally L-shaped part and is fabricated of metal. The L-shaped part includes an axial portion extending in the outward axial direction away from the ball bearing and a radial arm that extends radially from the axial arm toward the outer bearing race. The radial and axial arms each have an interior and exterior surface. The slinger 16, is adapted to engage the inner race 13 and abut a deflection means 11 on the seal element 17. A bearing cavity 21 is disposed between the seal element 17 and the slinger 16. The cavity 21 is filled with sealing means such as a lubricant or grease (not shown). The sealing means is one supporting element for the slinger and facilitates resistance to high external pressures by the bearing seal.

The inner and outer races (13, 15) define a radial plane. It will be understood that in one embodiment the bearing assembly 10 may be useful as a component of a rotating element in an apparatus. Thus, for example, the inner bearing race 13 may be affixed to a rotatable shaft and the outer bearing race 15 may be affixed to a support structure of the apparatus such that the notable shaft is both supported and free to rotate. The bearing assembly 10 thus has an axis of rotation lying through the center of the inner race 13 and about which the outer race 15 may rotate. Approximately perpendicular to the axis of rotation is a radial plane.

The seal element 17 spans a space between the inner and outer races (13, 15) such that the seal element 17 defines a radial plane The deflection means 11 is positioned axially outward from the radial plane. Thus, the deflection means 11 is positioned axially outward from either the inner race 13 or the outer race 15.

In order to form a seal between the inner race and the outer race the slinger 16 is pressed in toward the anti-frictional element 12 so as to push in the deflection means 11. The deflection means 11 engages the interior of the radial arm of the L-shaped part. The deflection means 11 may be bent inward by action of the slinger 16 and thus provide a close contact between the deflection means 11 and the slinger 16. When the slinger 16 is pushed inward, a seal is made. Contact between the deflection means 11 and the slinger 16 seals off the cavity 21 and is one means to prevent contaminants from entering the bearing or to seal against leakage of lubricant from the bearing cavity. The seal arrangement thus formed is illustrated in figure 2. In figure 2 the bearing assembly 10 is shown with the slinger 16 pressing against and pushing in or bending the deflection means 11. A comparison of figures 1 and 2 shows the relative change in position of both the slinger 16 and the deflection means 11.

Figure 3 shows the bearing seal of figure 2 in an exploded cross-sectional view. The bearing assembly 10 includes the inner race 13 and the outer race 15. In this embodiment, the bearing assembly 10 further includes at least a ball bearing 12. The ball bearing 12 is positioned by the bearing retainer 14. The seal element 17 is captured in the groove 18 in the outer race 15. The seal element 17 is adapted to engage the inner race 13. The slinger 16, is adapted to engage the inner race 13 and abut the deflection means 11 on the seal element 17. In order to form a seal between the inner race and the outer race the slinger 16 is pressed in toward the ball bearing 12 so as to push in or bend the deflection means 11. The cavity 21 is also further illustrated. The completed seal assembly of the present invention includes the slinger 16, the seal element 17 and the grease or sealing means (not shown), such that the slinger 16 is deflected axially inward towards the radial plane defined by the first and second grooves (18a, 18b) sealing the cavity 21 containing the grease. Thus, the slinger 16 presses the sealing means against the seal element 17, and the sealing means forms an element of the structure of the seal assembly of the present invention. The sealing means further forms and additional barrier to penetration by high-pressure fluids including high- pressure waters and high pressure steam.

Generally, the slinger 16 and the seal element 17 may be made of any suitable material known in the art such as, metal or plastic material compositions. The plastic material compositions would include structural thermoplastics. The slinger 16 and the seal element 17 may be fabricated as separate pieces or as an integral part. The deflection means 11 may be generally fabricated as a metal tab with suitable hardness, a deformable elastomeric part, a thermoplastic part or a resilient part made from a resinous material. The seal element 17 and the deflection means 11 may be fabricated as separate pieces or formed integrally.

The sealing means may be of any composition suitable to perform the function described above. The sealing means may include common viscous lubricants, petrolatums, semi-sold mixtures of hydrocarbons, semi-solid mixtures of fatty acid esters, greases and combinations of these substances. The sealing means is selected so that if may be interposed between the slinger 16 and the seal element 17 in the cavity 21 and so that it provides an additional barrier to penetration by high pressure water or high pressure steam.

The seal thus made is capable of withstanding high external pressures. A bearing assembly employing such a seal may be ideally suited for use on rotatable shafts used on machinery useful in the preparation of poultry as food products. Such machinery requires frequent high pressure cleaning to maintain sanitary standards. Typically, such machinery is cleaned using high-pressure steam and/or hot water. The bearing of the present invention, while simple in design, is capable of withstanding such high external pressures.

Because of the simplicity of the design of the bearing seal of the present invention, the seal disclosed herein is also of low cost. There has been provided, in accordance with the present invention, a bearing assembly having a low-cost seal capable of withstanding high external pressures. There has also been provided, in accordance with the present invention, a bearing seal that is simple in design yet able to withstand high pressures generated, for example, by the application of a high pressure steam and/or hot water stream to the bearing seal. While this invention has been described with specific embodiments, many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to include all such alternatives, modifications and variations set forth within the spirit and scope of the description.

Claims

What is claimed is:

1. A non-relubricable bearing assembly comprising: an outer bearing race defining a groove; an inner bearing race, the inner bearing race being in a radially spaced relationship with the outer bearing race to define a space; a plurality of anti-friction elements rotatably confined in the space; a seal element having a finger extension, the seal element disposed between the inner bearing race and the outer bearing race and rotatably retained in the groove, the seal element and the first leg defining a cavity, the fmger extension adapted to be deflected by movement of the first leg thus sealing the cavity, the seal element defining a radial plane; a generally L-shaped slinger defining a first leg and a second leg, the second leg connected to the inner bearing race and extending towards the radial plane, the first leg adapted to be pressably moved away from the radial plane towards the space; and a grease contained within the cavity, the grease providing a structural support against which the first leg is pressed upon deflection of the fmger extension.

2. The non-relubricable bearing assembly of Claim 1 wherein the seal element and the fmger extension are integrally formed.

3. The non-relubricable bearing assembly of Claim 1 wherein the slinger is fabricated of metal.

4. The non-relubricable bearing assembly of Claim 1 wherein the seal element is fabricated of metal.

5. The non-relubricable bearing assembly of Claim 1 wherein the seal element and the slinger are integrally formed.

6. The non-relubricable bearing assembly of Claim 1 wherein the anti-frictional elements are ball bearings.

7. A non-relubricable bearing assembly comprising: an outer bearing race defining a groove; an inner bearing race, the inner bearing race being in a radially spaced relationship with the outer bearing race to define a space; a plurality of anti-friction elements rotatably confined in the space; a seal element having means for deflection, the seal element disposed between the inner bearing race and the outer bearing race and rotatably retained in the first groove and the second groove, the seal element and the first leg defining a cavity, the deflection means adapted to be deflected by movement of the first leg thus sealing the cavity, the seal element defining a radial plane; a generally L-shaped slinger defining a first leg and a second leg, the second leg connected to the inner bearing race and extending towards the radial plane, the first leg adapted to be pressably moved away from the radial plane towards the space; and means for sealing the cavity, the sealing means contained within the cavity, the sealing means providing a structural support against which the first leg is pressed upon deflection of the deflection means.

8. The non-relubricable bearing assembly of Claim 7 wherein the seal element and the means for deflection are integrally formed.

9. The non-relubricable bearing assembly of Claim 7 wherein the slinger is fabricated of metal.

10. The non-relubricable bearing assembly of Claim 7 wherein the seal element is fabricated of metal.

11. The non-relubricable bearing assembly of Claim 7 wherein the seal element and the slinger are integrally formed.

12. The non-relubricable bearing assembly of Claim 7 wherein the anti-frictional elements are ball bearings.

13. The non-relubricable bearing assembly of Claim 7 wherein the sealing means is grease.