WO2007002903A1

WO2007002903A1 - Vibration damping device for bearings and method of dampening vibrations

Info

Publication number: WO2007002903A1
Application number: PCT/US2006/025628
Authority: WO
Inventors: Christian Adam
Original assignee: The Timken Company
Priority date: 2005-06-29
Filing date: 2006-06-29
Publication date: 2007-01-04

Abstract

A damping sleeve and method for damping vibrations applied to a bearing. In a suspension system 10 having a housing A and a bearing assembly 14 located in the housing A for supporting a shaft 16, the sleeve 52 dampens vibration effects that are generated by the rotating shaft 16. The bearing assembly 14 comprises a bearing 18 located in at least one bearing seat 12 and located around the shaft 16. The bearing 18 also includes an inner race 22 having an inner raceway 28, an outer race 24 having an outer raceway 30, and rolling elements 26 located between and contacting the inner race 22 and the outer race 24. The sleeve 52 fits to at least one of the inner race 22 and the outer race 24. The sleeve 52 comprises a formable, composite material 56, the formable, composite material 56 having opposing layers of metal 58 and a viscoelastic material 60 interposed between the opposing layers of metal 58 wherein the viscoelastic material 60 dampens vibrations caused by the shaft 16 and transmitted to at least one of the inner race 22 and the outer race 24.

Description

VIBRATION DAMPING DEVICE FOR BEARINGS AND METHOD OF DAMPENING VIBRATIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

This application derives and claims priority from U.S. provisional application 60/694,825, filed 29 June 2005, which is incorporated herein by reference.

BACKGROUND ART

The present disclosure relates to a vibration damping, and in particular, a vibration damping sleeve that fits to a bearing to limit vibrations transferred to the bearing from a moving component such as a rotating shaft.

A wide variety of machinery contains shafts that rotate in housings on antifriction bearings. During rotation, the shafts themselves have the capacity to generate vibrations, and further have the capacity to transmit vibrations to components that they carry, such as gears. Further, the bearings on which such shafts rotate and the associated gears transfer the vibrations to the housings. These vibrations generate noise and impact the components carried by the shaft.

In industrial applications, operators do not want to transfer lateral vibrations generated by the gears and shafts to the housing. The noise and harshness caused by the vibrations must be limited for efficient operation of the shaft and associated components. Further, the noise generated by the vibrations adversely impacts personnel operating the shaft and components. Additionally, the harshness applied by the vibrations to the components adversely impacts the life cycle of the components. As such, the vibrations caused by the rotating shaft require minimization for economic and safe operation for the shaft, components and personnel. SUMMARY OF THE INVENTION

The present disclosure relates to a bearing assembly having a sleeve that dampens vibrations. In a suspension system having a housing and a bearing assembly located in the housing for supporting a shaft, the sleeve of the present disclosure dampens vibration effects that are generated by the rotating shaft. The bearing assembly comprises a bearing located in at least one bearing seat and located around the shaft. The bearing also includes an inner race having an inner raceway, an outer race having an outer raceway, and rolling elements located between and contacting the inner race and the outer race.

The sleeve fits to at least one of the inner race and the outer race. The sleeve comprises a formable, composite material, the formable, composite material having opposing layers of metal and a viscoelastic material interposed between the opposing layers of metal wherein the viscoelastic material dampens vibrations caused by the shaft and transmitted to at least one of the inner race and the outer race.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which form part of the disclosure and wherein like numerals and letters refer to like parts wherever they occur:

Fig. 1 is an exploded sectional view of a tapered roller bearing supporting a shaft in a housing and being fitted with damping sleeves constructed in accordance with and embodying the present disclosure, the sleeves comprising a formable, composite material; Fig. 2 is a fragmentary perspective view, partially broken away and in section, of a single row roller bearing having a damping sleeve of the present disclosure fitted to its inner race;

Fig. 3 is a perspective view, partially broken away and in section, of a single row roller bearing having a damping sleeve of the present disclosure fitted to its outer race; Fig. 4 is a perspective view of a single row roller bearing having another damping sleeve of the present disclosure fitted to its outer race, the sleeve having an end wall that covers a back face of an outer race of the bearing; and Fig. 5 is a perspective view, partially broken away and in section, of a needle bearing having a damping sleeve of the present disclosure, wherein the sleeve forms the outer race.

BEST MODES FOR CARRYING OUT THE INVENTION

The following detailed description illustrates the disclosure by way of example and not by way of limitation. This description will clearly enable one skilled in the art to make and use the disclosure, and describes several embodiments, adaptations, variations, alternatives and uses of the disclosure, including what I presently believe is the best mode of carrying out the invention. Additionally, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The present disclosure relates to dampening vibrations created by rotating components such as shafts. In particular, the present disclosure relates to a vibration-damping sleeve in use with an antifriction bearing. The damping sleeve may be fitted, incorporated and/or integrated with a variety of bearings such as but not limited to cylindrical roller bearings, tapered roller bearings, spherical roller bearings, needle bearings, angular contact bearings and plain ball bearings. The formability of the present damping sleeves allows for a variety of uses for bearings. The following description illustrates tapered roller bearings and needle bearings as exemplary descriptions for the damping sleeve. The damping sleeve, however, is not limited to tapered roller bearings and needle bearings.

During operation of rotating shafts and associated components of the shaft, personnel monitor rotation variables. These variables may include but are not limited to noise, vibration and harshness, known as "NVH" variables. In all applications, the damping sleeve of the present disclosure interacts with the bearings supporting the shaft to limit the dilatory effects of vibration caused by the rotating shaft in such a way that the vibrations are not transmitted to the housing. For illustrative purposes, the following description illustrates the sleeve damping vibrations caused by the shaft and transmitted to the bearings and to the housing. One application of the sleeve relates to industrial use, for example, in high speed shafts.

Referring now to the drawings, a housing A (Fig. 1) mounts on a suspension system 10. The housing A defines an axis "X" of rotation and the housing A includes at least one bearing seat 12 aligned along an axis "X" of rotation. The housing A also includes a bearing assembly generally shown as 14 located in the at least one bearing seat 12 for supporting a shaft 16. The bearing assembly 14 enables the shaft 16 to rotate relative to the axis "X" of rotation with relatively little friction. The bearing assembly 14 comprises a bearing 18 and at least one sleeve 20. The bearing 18 is located in the bearing seat 12 and around the shaft 16, while the sleeve 20 fits to the bearing 18 as will discussed.

The bearing 18, while permitting the shaft 16 to rotate about the axis "X" of rotation, confines the shaft radially and axially within the housing. In other words, the bearing 18 transfers radial loads between the shaft 16 and the housing A and also thrust loads in axial directions. The bearing 18 includes an inner race 22 in the form of a cone, an outer race 24 in the form of a cup and rolling elements 26 in the form of rollers. The inner race 22 has an inner raceway 28 that may incline with respect to the axis "X" of rotation, and the outer race 24 has an outer raceway 30 that may incline with respect to the axis "X" of rotation. The rolling elements 26 are located between and contact the inner race 22 and the outer race 24. The rolling elements 26 are confined within cages 32, which distribute the rolling elements 26 uniformly and thereby maintain the proper spacing between the rolling elements 26. The cages 32 also retain the rolling elements 26 around the inner race 22 when the inner race 22 is withdrawn from the housing/outer race. The rolling elements 26 transmit thrust and radial loads between the outer racer 24 and the inner race 22, while reducing friction to a minimum. The housing A contains a cylindrical bearing seat 34 that ends at a shoulder 36 (Fig. 1). The shaft 16 includes a cylindrical bearing seat 38 that leads away from a shoulder 40. Fig. 1 illustrates the bearing 18 being located in the bearing seat 12 and located around the shaft 16.

The inner race 22 has a cylindrical bore 42, the surface of which is presented inwardly toward the axis "X". The inner race 22 also has the tapered raceway 28 presented outwardly away from the axis "X" and has a thrust rib 44 at the large end of the raceway 28. The thrust rib 44 runs out to a back face 46 of the inner race 22 that is squared off with respect to the axis "X". The outer race 24 has a cylindrical outside surface 48 that is presented away from the axis "X" and the tapered raceway 30 that is presented inwardly toward the axis "X" and toward the raceway 28 of the inner race 22. The raceway 30 of the outer race 24 at its small end runs out to a back face 50 that is squared off with respect to the axis "X". The rolling elements 26 lie in a single row between the inner race 22 and outer race 24, with their tapered side faces contacting the raceways 28, 30 and the large end faces 46, 50 bearing against the thrust rib 44.

In the operation of bearing 18, the rolling elements 26 roll along the raceways 28 and 30 and transfer radial loads between the inner race 22 and outer race 24 - loads which are applied at the surface of the bore 42 and at the outside surface 48 of the outer race 24. The rolling elements 26 also transfer axial loads between the inner race 22 and outer race 24 - loads which are applied at the back face 46 of the inner race 22 and the back face 50 of the outer race 24. The thrust rib 44 of the inner race 22 prevents the rolling elements 26 from migrating up the raceways 28, 30 and being expelled from the annular space between the inner race 22 and outer race 24.

During operation, the bearing 18 transfers vibrations generated by the rotating shaft 16, and when the housing A is subjected to such vibrations of sufficient amplitude, the vibrations produce adverse noise. Additionally, the generated vibrations produce adverse motion effects to the housing A and the associated components (not shown) of the suspension system 10. The shaft 16 at the bearing 18, however, is isolated from the housing A by the at least one sleeve 20. In one embodiment, the sleeve 20 comprises an inner damping sleeve 52 or an outer damping sleeve 54 or by both. Inner damping sleeve 52 and outer damping sleeve 54 comprise formable configurations to contact any surface area of the bearing 18, shaft 16 and housing A. As such, the inner damping sleeve 52 may conform to the interface between the bearing 18 and the shaft 16. The inner damping sleeve 52, when on the bearing 18, fits over the seat 38 of the shaft and against the shoulder 40 of the shaft 16. The outer damping sleeve 54 may conform to the interface between the bearing 18 and housing A. The outer damping sleeve 54, when on the bearing 18, fits into the seat 34 and against the shoulder 36. The bearing 18 may be operated with only one of the sleeves 52 or 54 or with both of them. The sleeves 52, 54 fit to at least one of the inner, outer race 22,

24 to damp vibrations to which the respective race 22, 24 is subjected so that the vibrations are transmitted with less intensity. As shown in Fig. 1 , each sleeve 52 and 54 comprises a formable, composite material 56 comprised of two thin opposing sheets 58 and a dampening layer 60 interposed between the sheets 58. In one embodiment, the composite material 56 comprises two steel sheets joined by a viscoelastic resin. One form of the composite material 56 may comprise the material sold under the brand Sollight ® AC owned by the Arcelor Group.

The dampening layer 60 may comprise a viscoelastic resin such as a thermoplastic polymer material while the thin sheets 58 may comprise plain carbon steel. The thickness of the composite 56 should range between 0.6mm and 1.5mm. In other embodiments, the thickness of the composite 56 may be less than or equal to .6mm and greater than or equal to 1.5mm. The dampening layer 60 should range in thickness between 25μ and 50μ. This thickness range of the dampening layer 60 limits stiffness loss of the bearing 18. The two sheets 58 are generally equal in thickness. The sheets 58 assist in resisting contact pressure while the dampening layer 60 dampens vibrations caused by the shaft 16 without reducing support stiffness.

Composite steel, including at least one viscoelastic damping layer, such as steel produced for sound damping auto body panels may be used for the composite 56 of the sleeves 52 and 54. This composite 56 is used since the viscoelastic material adheres to the external sheet 58, which experiences the contact pressure and wear of the bearing 18. The composite 56 of the present disclosure allows for enhanced formability such as deep drawing, bending, roll forming, cutting and stamping. Furthermore, the composite 56 may be formable to configure to the shape of the contacting surface such as the surface between the inner race 22 and bearing seat 38 of the shaft 16 and the surface between the outer race 24 and the bearing seat 34 of the housing A. The draw ability of the composite maybe equivalent to that of conventional steel of the same thickness.

As noted, the inner sleeve 52 may fit between the inner race 22 of the bearing 18 and the shaft 16. In an embodiment, the inner sleeve 52 may fit between the inner race 22 and the bearing seat 38. The inner sleeve 52 may include (Figs. 1 & 2) an axial segment 62 and a radial segment 64 that projects outwardly from the axial segment 62 at one end of the axial segment 62. The axial segment 62 fits into the bore 42 with a slight interference fit, whereas the radial segment 64 lies along and/or extends over the back face 46, the radial segment 64 being perpendicular to the axis "X". Indeed, the bearing 18 may be furnished with the sleeve 52 fitted to its inner race 22 along the surface of the inner race 22. When the sleeve 52 is so fitted, the inside diameter of its axial segment 62 will establish an interference fit with the bearing seat 38 on the shaft 16, whereas the radial segment 64 will lie between the back face 46 and the shaft shoulder 40.

The outer sleeve 54 may fit between the outer race 24 of the bearing 18 and the housing A. In an embodiment, the outer sleeve 54 may fit between the outer race 24 and the cylindrical bearing seat 34. The outer sleeve 54 likewise includes (Figs. 1 & 3) an axial segment 66 and a radial segment 68, but the radial segment 68 turns inwardly from one end of the axial segment 66 where it is oriented perpendicular to the axial segments 66 and the axis "X". The axial segment 66 fits over the outside surface 48 of the outer race 24 with a slight interference fit, whereas the radial segment 68 lies against and/or extends over the back face 50. Indeed, the bearing 18 may be supplied with the sleeve 54 so fitted along the surface of the outer race 24. When the sleeve 54 is fitted to the outer race 24, its outer diameter should be such that a slight interference fit will exist between the outer race 24 and the bearing seat 34 of the housing A. The radial segment 68 lays between the back face 50 and the shoulder 36 of the housing A. With respect to both sleeves 52, 54, the interference fit may relate to a press fit and/or an integration of the sleeves 52, 54 to the bearing 18.

In the operation of the bearing 18 and sleeves 52 and 54, radial loads transfer from the shaft 16 to the inner race 22 of the bearing 18 through the axial segment 62 of the inner sleeve 52. Those same radial loads transfer between the outer race 24 and the housing A through the axial segment 68 of the outer sleeve 54. Thrust loads transfer between the inner race 22 and shaft 16 at the radial segment 64 of the inner sleeve 54 and between the outer race 24 and housing A at the radial segment 68 of the outer sleeve 54.

The sheets 58 of the composite 56 of the inner sleeve 52 resist the contact pressures at the shaft seat 38 and surface of the bore 42 and likewise at the shaft shoulder 40 and back face 46. The sheets 58 of the outer sleeve 54 resist contact pressure at the housing seat 34 and at the outside surface 48 of the outer race 24 and likewise at the housing shoulder 36 and back face 50. Accordingly, the sheets 58 adapt to dampen any pressure interface of the bearing 18. Due to the formability of the composite 56, the composite 56 reduces vibration damping in both the radial and axial directions. As such, the present disclosure reduces shear of the dampening layer 60. The dampening layer 60 in the two sleeves 52 and 54 damp vibrations to reduce sound vibrations, yet do not detract significantly from support stiffness. A modified damping sleeve 70 (Fig. 4) is similar to the outer sleeve 54, except that Jt has an end wall 72 that not only backs the back face 50, but further closes the entire end of the bearing 18. The damping sleeve 70 provides a damping closing wall for housing A. The damping sleeve 70 in contact with bearing 18 may also assist in resisting compression forces while the end wall 72 may assist in resisting expansion forces. The damping sleeve 70 also comprises the sheets 58 and the dampening layer 60 disposed there between.

Another modified damping sleeve 74 (Fig. 5) is shown for use with a needle bearing 18 having rolling elements 26 contained within the cage 32. In this embodiment, the inner race and/or the outer race may be drawn during manufacturing from the actual composite 56. In other words, the sleeve 74 does not comprise an additional sleeve that isolates bearing 18; but instead, the sleeve 74 becomes part of the bearing 18. As shown in Figure 5, the outer race 24 comprises the sheets 58 surrounding the dampening layer 60. In another embodiment (not shown), the inner race 22 may comprise the sheets 58 surrounding the dampening layer 60. The sleeves 52, 54, 70 and 74 may be provided without their respective radial segments 64 and 68, particularly when thrust loads are light. Moreover, the sleeve 52, 54, 70 and 74 and variations of them may be used on other types of tapered roller bearings, such as double row bearings, and indeed on other types of antifriction bearings such as but not limited to plain ball bearings, angular contact ball bearings, spherical roller bearings, angular contact bearings and cylindrical roller bearings.

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.

Claims

CLAlMS:

1. In combination with a suspension system having a housing that defines an axis of rotation there through, the housing includes at least one bearing seat aligned along an axis and includes a bearing assembly located in the at least one bearing seat for supporting a shaft, the bearing assembly, comprising: a bearing located in the at least one bearing seat and located around the shaft, the bearing includes an inner race having an inner raceway, an outer race having an outer raceway and rolling elements located between and contacting the inner race and the outer race; and a sleeve fitted to at least one of the inner race and the outer race, the sleeve comprises a formable, composite material, the formable, composite material having opposing layers of metal and a viscoelastic material interposed between the opposing layers of metal wherein the viscoelastic material dampens vibrations caused by the shaft and transmitted to at least one of the inner race and the outer race.

2. The bearing assembly according to claim 1 wherein the sleeve is located between the housing and the shaft.

3. The bearing assembly according to claim 2 wherein the sleeve has an axial segment that lies along the inner race.

4. The bearing assembly according to claim 1 wherein the sleeve is located between the shaft and the housing.

5. The bearing assembly according to claim 4 wherein the sleeve has an axial segment that lies along the outer race and within the bearing seat.

6. The bearing assembly of claim 1 wherein each outer and inner race also has a back face at which thrust loads are applied to the races, and wherein the sleeve includes a radially directed segment that extends over the back face of the race to which the sleeve is fitted.

7. The bearing assembly of claim 1 wherein the outer race has a back face and wherein the sleeve includes an end wall that covers the back face of the outer race.

8. In a bearing assembly positioned within a housing, the bearing assembly having at least one bearing aligned along an axis of a shaft, the bearing includes an inner race, an outer race and rolling elements located between and contacting the inner race and outer race, the improvement comprising: at least one sleeve fitted to at least one of the inner race and the outer race, the at least one sleeve comprises a formable, composite material, the formable, composite material having opposing layers of metal and a viscoelastic material interposed between the opposing layers of metal wherein the viscoelastic material dampens vibrations caused by the shaft and transmitted to at least one of the inner race and the outer race.

9. The improvement according to claim 8 wherein the at least one sleeve comprises a first sleeve that is located between the housing and the shaft.

10. The improvement according to claim 8 wherein the at least one sleeve comprises a second sleeve that is located between the housing and the shaft.

11. The improvement of claim 8 wherein each outer and inner race also has a back face at which thrust loads are applied to the races, and wherein the at least one sleeve includes a radially directed segment that extends over the back face of the race to which the sleeve is fitted.

12. The improvement of claim 8 wherein the outer race has a back face and wherein the at least one sleeve further includes an end wall that covers the back face of the outer race.

13. In a housing defining an axis of rotation there through and having at least one bearing seat aligned along an axis, the housing includes a bearing assembly located in the at least one bearing seat for supporting a shaft, the bearing assembly, comprising: a bearing located in the at least one bearing seat and located around the shaft, the bearing includes, an inner race, an outer race, and rolling elements located between and contacting the inner race and the outer race, wherein at least one of the inner race and outer race comprises a sleeve having a formable, composite material, the formable, composite material having opposing layers of metal and a viscoelastic material interposed between the opposing layers of metal wherein the viscoelastic material dampens vibrations caused by the shaft and transmitted to the housing.

14. The bearing assembly of claim 13 wherein the sleeve has an axial segment that lies along and around the shaft.

15. The bearing assembly according to claim 13 wherein the sleeve has an axial segment that lies along and within the housing.

16. The bearing assembly according to claim 13 wherein the outer race has a back face and wherein the sleeve includes an end wall that covers the back face of the outer race.

17. The bearing assembly of claim 13 wherein the bearing comprises a needle bearing.

18. A method of dampening vibrations caused by a shaft that is supported by a bearing, the method comprises: fitting a sleeve to at least one of an inner race and an outer race of the bearing, the sleeve comprises a formable, composite material, the formable, composite material having opposing layers of metal and a viscoelastic material interposed between the opposing layers of metal wherein the viscoelastic material dampens vibrations caused by the shaft and transmitted to at least one of the inner race and the outer race.

19. The method according to claim 18 wherein fitting the sleeve comprises locating the sleeve between the inner race and the shaft.

20. The method according to claim 18 wherein fitting the sleeve comprises locating the sleeve between the outer race and the housing.