WO2011019703A1 - Method and apparatus for bearing race creep prevention - Google Patents

Abstract

A bearing assembly 40 for supporting a rotating shaft 20 relative to a supporting housing 28, in which the inner races 100A, 100B of the bearing assembly incorporate integrated backface recessed features 200 configured to secure the inner races 100A, 100B relative to the rotating shaft 20 upon which they are mounted, to reduce or eliminate creep, fretting, and relative rotation between the inner races 100A, 100B and the shaft 20. The backface surface 104 of each inner race 100A, 100B incorporates at least one recessed feature 200 within an annular region 102 which abuts a retaining portion 25, 30 of the corresponding shaft 20 upon which the races 100A, 100B are mounted, such that during placement of the bearing assembly 40 on the shaft 20, deformation of the shaft material abutting each of the inner race backfaces into the recessed dimples or slots acts to "lock" the inner races 100A, 100B against rotational movement relative to the shaft 20.

Description

TIMK D314WO - APPLICATION - FINAL

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METHOD AND APPARATUS FOR BEARING RACE CREEP PREVENTION

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to, and claims priority from, U.S. Provisional

Patent Application Serial No. 61/232,574 filed on August 10, 2009, which is herein incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

BACKGROUND OF THE INVENTION

The present invention relates generally to bearing assemblies, such as found in vehicle wheel hub assemblies, for supporting rotating components, and in particular, to a method and assembly for reducing or eliminating creep or relative rotation between one or more races of the bearing assembly and the adjacent components upon which the bearing assembly is mounted.

Various bearing assemblies for supporting a rotating member axially relative to a fixed or stationary member are known. Rolling elements in these bearing assemblies are disposed between inner and outer races fitted to the members being supported, and provide rolling support between the two members. One common application for bearing assemblies is in the mounting the road wheels of automotive vehicles on the suspension systems of such vehicle. One arrangement relies on a dead spindle which projects from the suspension system - usually from a steering knuckle - into a hub to which a road wheel is bolted. The hub rotates around the spindle on antifriction bearings that are located between the hub and the spindle. In another arrangement, the hub to which the road wheel is bolted has a live spindle which projects into a housing which in turn is bolted to a steering knuckle or other suspension system component. An antifriction bearing located between the spindle and housing enables the spindle - and indeed the entire hub - to rotate relative to the housing.

Within vehicle wheel hub assemblies, as well as other types of bearing assemblies, the antifriction bearing consists of one or more rows of rolling elements TIMK D314WO - APPLICATION - FINAL

-?- disposed between outer races secured or integrated with the housing, and inner races which are associated with the rotating shaft or spindle which passes through the housing. During use, and particularly when experiencing high bending loads, the inner races may flex or bend in relation to the outer diameter of the rotating shaft or spindle with which they are associated. Over time, repeated flexing and bending motion may cause the inner races to "turn", "creep", "fret", or 'index" about the rotating shaft or spindle, result in stress risers and crack initiation points which can reduce cyclical fatigue life. In the converse mounting arrangement, similar repeated flexing and bending motions can cause an outer race to "turn", "creep", "fret", or 'index" relative to a rotating housing or outer structure, result in stress risers and crack initiation points which can reduce cyclical fatigue life when the bearing is mounted about a stationary or fixed axial shaft.

Accordingly, it would be advantageous to provide a provide a bearing assembly with features to prevent incremental relative rotation of the bearing races relative to the rotating component upon which they are mounted, and which reduced the formation of stress risers and crack initiation points leading to a reduced cyclical fatigue life of the bearing assembly.

BRIEF SUMMARY OF THE INVENTION

Briefly stated, the present disclosure provides a bearing assembly having one or more races associated with a rotating structure with backface features which are adapted to rotationally secure the races relative to the rotating structure supported by the bearing. The backface features provide a positive engagement between the one or more races and the rotating structure to reduce or eliminate creep, fretting, and relative rotation between the supported races and the associated rotating structure, such that the races rotate with the rotating structure

In one embodiment, the present disclosure provides at least one inner race of a bearing assembly with an integrated backface engagement feature configured to secure the inner race relative to a corresponding rotating shaft upon which the bearing assembly is mounted, to reduce or eliminate creep, fretting, and relative rotation between the inner race and the corresponding shaft. TIMK D314WO - APPLICATION - FINAL

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In one embodiment, the present disclosure provides at least one outer race of a bearing assembly with an integrated backface engagement feature configured to secure the outer race relative to a corresponding rotating structure within which the bearing assembly is mounted, to reduce or eliminate creep, fretting, and relative rotation between the outer race and the corresponding enclosing and rotating structure.

In an alternate embodiment embodiment, the backface of each discrete race component incorporates at least one engagement feature within an annular region which abuts a retention element of the corresponding rotating structure upon which the races are mounted. The retention element may be formed material from the rotating structure or other suitable retention means. During placement of the bearing assembly onto the corresponding rotating structure, retention element material abutting an annular portion of the race backfaces flows under pressure or is deformed into positive engagement with the engagement feature of the asscoaited races, and acts to "lock" the races against rotational movement relative to the corresponding rotating structure and retention element.

The foregoing features, and advantages set forth in the present disclosure as well as presently preferred embodiments will become more apparent from the reading of the following description in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the accompanying drawings which form part of the specification:

Figure 1 is a partial sectional view of an exemplary vehicle wheel hub assembly illustrating the positioning of inboard and outboard inner races of a bearing assembly relative to a rotating spindle shaft; and

Figure 2 is an end view of an inner race backface surface in the vehicle wheel hub assembly of Fig. 1 , illustrating a plurality of engagement features.

Figure 3 is a perspective partial end view of a bearing race backface surface incorporating a recessed radial channel as an engagement feature; TIMK D314WO - APPLICATION - FINAL

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Figure 4 is a perspective partial end view of a bearing race backface surface against which a separate engagement element in the form of a woven wire mesh is disposed;

Figure 5 is a perspective partial end view of a bearing race backface surface incorporating a dimple engagement feature; and

Figure 6 is a perspective partial end view of a bearing race incorporating an axial groove engagement feature on an inner circumferential surface.

Corresponding reference numerals indicate corresponding parts throughout the several figures of the drawings. It is to be understood that the drawings are for illustrating the concepts set forth in the present disclosure and are not to scale.

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings.

DETAILED DESCRIPTION

The following detailed description illustrates the invention by way of example and not by way of limitation. The description enables one skilled in the art to make and use the present disclosure, and describes several embodiments, adaptations, variations, alternatives, and uses of the present disclosure, including what is presently believed to be the best mode of carrying out the present disclosure.

Although described below in the exemplary context of a vehicle wheel hub and bearing assembly 10 as shown in Figure 1 , it will be recognized that the features and concepts of the present disclosure are applicable generally to a wide range of bearing assemblies 40 having at least one race member 100 which is secured against a rotating component 20, such as a rotating shaft, and which is held in place by a retention element 30, such as a shoulder, formed region, or other attachment structure which applies an axially-directed force against an annular portion 102 of the race backface surface 104.

Turning to the figures generally, and to Figures 1 and 2 specifically, an exemplary vehicle wheel hub and bearing assembly 10 is shown consisting of a TIMK D314WO - APPLICATION - FINAL

-5- rotating component 20 onto which a vehicle wheel is secured by multiple wheel lug bolts 22 on an outboard end. The vehicle wheel hub and bearing assembly 10 enables a vehicle wheel and brake disk to rotate about an axis X on a steering knuckle or other component of an automotive suspension system (not shown). The vehicle wheel hub and bearing assembly 10 includes a hub 24 defined by the rotating spindle 22 and bolt flange 26, to which the road wheel and brake disk are secured, a housing 28 which is mounted on the steering knuckle or other suspension component, and a bearing 40 which is located between the hub 24 and housing 28, and which enables the hub 24 to rotate within the housing 28 with minimum friction.

More specifically, the hub 24 includes the flange 26 and rotating spindle 20 which projects from the flange 26 at a shoulder 25 located on the back face 27 of the flange. Outwardly from the shoulder, the flange 26 is fitted with the lug bolts 22 which project axially from the opposite face. A brake disk (not shown) fits against the flange 26 and the road wheel (not shown) fits against the disk with the lug bolts projecting though each of them. Beyond the wheel, lug nuts (not shown) are threaded over the bolts to secure the disk and wheel to the hub.

At an end remote from the flange 26, the spindle 20 is upset to define a race / bearing retaining element 30, that is, the spindle 20 is deformed outwardly in the provision of a roll formed end having an abutment face that lies perpendicular to the axis X and is presented toward the flange 26. The inner races 100 of the bearing 40 are captured between the shoulder 25 on the flange 26 and the roll-formed abutment face of the retaining element 30. The bearing 40 includes a set of inner races 100 which may be in the form of a discrete inboard inner race 100A and a discrete outboard inner race 100B which fit around the spindle 20, there being an interference fit between each inner race 100A, 100B and the spindle. Alternatively, the set of inner races 100 may have only a single discrete inboard inner race 100A, with the outboard inner race 100B integrally formed with the spindle 20 outer diameter surface. Each discrete inner race 100A, 100B has a tapered raceway 105 that is presented outwardly away from the axis X, a thrust rib 106 at the large end of its raceway, and a back face 102, which is squared off with respect to the axis X on TIMK D314WO - APPLICATION - FINAL

-6- thθ end of the thrust rib 106. The inboard inner race 100A abuts the small end of the outboard inner race 100B along the spindle 20, that is to say, the two inner races abut at their front faces. The roll formed abutment face of the retaining element 30, and the flange shoulder 25 if required, each serve as an abutment for a backface 102 of the inboard and outboard inner races 10OA, 100B, respectively.

In addition to the inner races 100, the bearing 40 includes rolling elements 108 such as tapered rollers arranged in two rows, there being a separate row around each inner race 100A, 100B. Actually, the rolling elements 108 extend around the raceways for the inner races 100A, 100B, and with tapered rollers, there being essentially a line contact between the tapered side faces of the rollers and the raceways. For tapered rollers, preferably the large end faces of the rollers bear against the thrust ribs 106, with the rollers of each row essentially on apex, which means that the envelopes in which their tapered side faces lie have their apices located at a common point along the axis. Each row of rollers 108 has a cage 1 10 to maintain the proper spacing between the rolling elements 108 in that row.

The housing 28 surrounds the spindle 20 as well as the set of inner races 100, and the two rows of rolling elements 108. The housing 28 forms part of the bearing 40 in that the housing supports the raceways 1 12A and 1 12B which are presented inwardly toward the axis. In that sense, the housing 28 constitutes a set of outer races 1 12 of the bearing 40. When utilized with tapered rollers, the raceways 1 12A and 1 12B on the housing taper downwardly toward an intervening surface which separates them. The rolling elements 108 likewise lie along the raceways 1 12A and 1 12B of the housing 28, and for tapered rollers, there being essentially a line contact between the raceways 1 12A and 1 12B and the tapered side faces of the rollers. At their large ends, the raceways 1 12A and 1 12B open into short end bores in which the thrust ribs 106 of the two inner races 100 are located.

During use, and particularly when experiencing high bending loads, the discrete inner races 100 may flex or bend in relation to the outer diameter of the rotating shaft or spindle 20 with which they are associated. Over time, repeated flexing and bending motion may cause the inner races 100 to "turn", "creep", "fret", TIMK D314WO - APPLICATION - FINAL

-7- or 'index" about the rotating shaft or spindle 20, result in stress risers and crack initiation points which can reduce cyclical fatigue life. To reduce or eliminate the rotational movement of the set of inner races 100 relative to the rotating component 20, each backface surface 104 incorporates one or more engagement features 200, such as recessed slots 200A (Figure 3) or depressions 200B (Figure 5), or combinations thereof (Figure 2) within the annular region of abutment 102.

The engagement features 200, such as recessed slots 200A, depressions 200B, or combinations thereof within the annular region of abutment 102 on each inner race backface surface 104 provide recessed regions or spaces into which material from the retention element 30 may flow or deform under axial pressure during the assembly process, thereby providing a positive "lock" or engagement between each discrete inner race 100 and the rotating component 20 onto which it is mounted. The resulting positive "lock" or engagement resists the gradual rotational movement or creep of the inner races 100 relative to the rotating component 20, thereby reducing or eliminating the formation of associated stress risers and crack initiation points. To facilitate deformation of the retention element 30 into the engagement features 200 of the inner race backface surface 104, it is preferable that the inner race 100 be formed from a material which is harder than that of the retention element 30.

As various changes could be made in the above constructions without departing from the scope of the disclosure, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. Those of ordinary skill in the art will recognize that while the present disclosure has been described in the context of securing bearing inner races 100 against rotation relative to an axially supported rotating shaft such as a spindle 20, the apparatus and methods set forth herein may be adapted for utilization in the converse application, wherein the rotating component 20 is actually the enclosing outer structure or housing 28 into which one or more discrete outer races 1 12 are positively secured by retention elements 30 and engagement features 200 against rotational movement relative thereto. Further, TIMK D314WO - APPLICATION - FINAL

it will be recognized that the concepts of the present disclosure are not limited to use in vehicle hub and bearing assemblies 10, and may be broadly utilized in a variety of bearing applications wherein inner or outer races are potentially subjected to rotational movement relative to a supported or enclosing component or structure.

The present disclosure will be seen as providing method for securing an annular race 100 of a bearing 40 against rotational movement relative to an axially supported component 20. The fundamental steps in the method require positioning at least one bearing race in operational association with the axially supported component 20; disposing at least one engagement feature between a surface of the bearing race and a surface of the axially supported component; and engaging the engagement feature with the surface of the axially supported component and the surface of the bearing race to positively engage the bearing race with the axially supported component, thereby providing a resistance to rotational movement of the bearing race relative to the supported component. The positive engagement between the bearing race and the axially supported component may be achieved by deforming a portion of the axially supported component, such as a retention element into positive engagement with the engagement feature. The engagement feature itself may be a recessed feature selected from a set of recessed features including slots, channels, grooves, dimples, knurls, or cross-hatching integrally formed in a surface of the bearing race, such as the backface surface or an axial surface, or it may be an engagement structure which is discrete from said race and the axially supported component and is entrapped there between when the race is secured to the axially supported component.

Those of ordinary skill will recognize that a variety of retention elements 30 may be utilized to secure the bearing races 100 relative to the associated rotating components or structures, and hence to interact with the engagement features 200 on the race backface surfaces 104 to secure the races 100 against rotational movement relative to their associated rotating components 20 or structures. These retention elements 30 may include formed ends or portion of the associated rotating components 20 or structures, shoulders, flanges, and the like, provided that the TIMK D314WO - APPLICATION - FINAL

-9- material of the retention elements 30 is sufficiently ductile relative to the material of the races 100, to deform or flow under pressure into the engagement features 200 on the bearing race backfaces surfaces 104 as described herein.

It will be recognized that a variety of engagement features 200 may be utilized to facilitate positive engagement between the race backface surfaces 104 of either an inner race 100 or an outer race 1 12 and a retention element 30 associated with a rotating component 20 onto which the race is mounted. In addition to the grooves 200A, dimples 200B, or other surface features which may be formed in the backface surfaces 104 of the race, a discrete engagement structure 300 may be interposed between the race backface surface 104 and the retention element 30 of the rotating component. For example, as shown in Figure 4, an engagement structure 300 in the form of a wire mesh segment is disposed against the race backface surface 104. When the retention element 30 is abuttingly engaged with the race backface surface 104, the engagement structure 300 is entrapped there between, and positively engages both the rentention element 30 and the race backface surface 104, providing a resistation to relative rotational movement. The engagement structure 300 may have a variety of configurations, provided that positive engagement between the retention element 30 and the race backface surface 104 is enabled. For example the wire mesh segment shown in Figure 4 may be replaced by a knurled or cross-hatched washer.

Finally, it will be recognized that the the engagement features 200 utilizes to facilitate positive engagement between the surfaces of either an inner race 100 or an outer race 1 12 and a retention element 30 associated with a rotating component 20 onto which the race is mounted are not limited to placement on the race backface surface 104. For example, as shown in Figure 6, an axial engagement feature 400 in the form of a channel or groove may be disposed on an axial surface of the race which is then positively engaged with an axial surface of the rotating component 20, such as a shaft outer diameter.

Claims

TIMK D314WO - APPLICATION - FINAL -10- CLAIMS:

1 . A bearing assembly 40 adapted for axially supporting a rotating component relative to a stationary component, including a set of rolling elements 108 disposed between a set of outer races and a set of inner races, comprising: at least one engagement feature 200, 300, 400 associated with a surface of at least one of said races in said set of races mounted to the rotating component 20; and

wherein said race surface is adapted for engagement with the rotating component and whereby each of said engagement features positively engages said rotating component with said race surface, thereby providing a resistance to rotational movement of said at least one race relative to said rotating component.

2. The bearing assembly of Claim 1 wherein said engagement feature 200, 300 is disposed on a backface surface 104 of said race, said backface surface adapted for engagement with a retention element 30 of the rotating component 20, and wherein said engagement feature 200, 300 positively engages said retention element.

3. The bearing assembly of Claim 1 wherein said engagement feature 400 is disposed on an axial surface of said race and positively engages a facing axial surface of said rotating component.

4. The bearing assembly of Claim 1 wherein said rotating component is an axial shaft, and wherein said engagement feature is disposed on a surface of said set of inner races mounted to said axial shaft.

5. The bearing assembly of Claim 1 wherein said rotating component is an external housing, and wherein said engagement features is disposed on a surface of said set of outer races mounted to said external housing.

6. The bearing assembly of Claim 1 wherein said rotating component is a shaft 20 of a vehicle wheel assembly spindle, and wherein said retention element 30 is a formed end of the spindle abutting a backface 104 of an inboard inner race 100A, said engagement feature disposed on said backface 104 of said inboard inner race 10OA to positively engage said formed end of the spindle. TIMK D314WO - APPLICATION - FINAL

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7. The bearing assembly of Claim 6 wherein said vehicle wheel assembly spindle further includes a flange shoulder 25 abutting a backface 104 of an outboard inner race 100B, and further including at least one engagement feature disposed on said backface surface 104 of said outboard inner race 100B to positively engage said flange shoulder 25.

8. The bearing assembly of Claim 1 wherein said positive engagement between each of said plurality of engagement features 200 and said rotating component includes a deformation of material from said rotating component into a recessed structure of said engagement feature 200.

9. The bearing assembly of Claim 1 wherein said engagement feature

200, 400 associated with surfaces of said set of races 100 includes at least one dimple, slot, or depression.

10. The bearing assembly of Claim 1 wherein said engagement feature 300 is an engagement structure interposed between said race surface and said rotating component surface.

1 1 . The bearing assembly of Claim 10 wherein said engagement structure is a mesh segment or knurled washer interposed between a backface surface 104 of said race and a retention element 30 of the rotating component 20, and wherein said engagement structure 400 positively engages both said backface surface and said retention element to resist relative rotation there between.

12. The bearing assembly of Claim 1 wherein each of said engagement features has a material hardness which is greater than the material hardness of at least one of said surfaces in abutting engagement therewith.

13. A method for securing an annular race 100 of a bearing 40 against rotational movement relative to an axially supported component 20, comprising: positioning said race in operational association with said axially supported component 20;

disposing at least one engagement feature between a surface of said race and a surface of said axially supported component; and TIMK D314WO - APPLICATION - FINAL

-12- engaging said engagement feature with the surface of said axially supported component and said surface of said race to positively engage said race with said axially supported component, thereby providing a resistance to rotational movement of the race relative to said supported component.

14. The method of Claim 13 further including the step of deforming a portion of said surface of said axially supported component into positive engagement with said engagement feature.

15. The method of Claim 13 wherein said step of disposing includes integrally forming said at least one engagement feature in said surface of said race.

16. The method of Claim 15 wherein said surface of said race is a backface surface, and wherein said engagement feature is a recessed feature selected from a set of recessed features including slots, channels, grooves, dimples, knurls, or cross-hatching.

17. The method of Claim 13 wherein said engagement feature is an engagement structure which is discrete from said race and said axially supported component.

18. The method of Claim 13 wherein said step of engaging includes deforming a portion of said axially supported component into engagement with said surface of said race, said deformation entrapping said at least one engagement feature there between.