WO2005075844A1

WO2005075844A1 - Roller bearing assembly

Info

Publication number: WO2005075844A1
Application number: PCT/BE2005/000014
Authority: WO
Inventors: Marcel De Wilde; Johan Constant Albert Goossens
Original assignee: Hansen Transmissions International, Naamloze Vennootschap
Priority date: 2004-02-03
Filing date: 2005-02-02
Publication date: 2005-08-18
Also published as: GB0402254D0; GB0502193D0; GB2410773A

Abstract

A roller bearing assembly (10) comprises a plurality of bearing rollers (12) located between confronting bearing surfaces (14, 15) , said bearing surfaces being rotatable one relative to the other about the rotational axis of the bearing, at least one of said bearing surfaces comprising an annular abutment surface (18) which restricts movement of the rollers in an axial direction parallel with the rotational axis of each roller, and said bearing assembly comprising biasing means (19) which acts in a direction parallel with said axis of rotation of the rollers to urge the bearing rollers against said annular abutment surface (18).

Description

ROLLER BEARING ASSEMBLY

This invention relates to a roller bearing assembly and in particular,,though not exclusively, to a roller beaπng suitable for use in a wind turbine gear unit.

There is a need for the bearings in wind turbine gear units to cope with operating conditions that can vary significantly between high load operation and operation at low load or even no load and high speed.

There is a significant risk that slippage of the rollers will occur on the raceways, and that said slippage can lead to damage of the bearing surfaces of the rollers and raceways, with consequential bearing failure.

Because the size of the bearings required for use in the gear units of wind turbines is increasing with increasing size of the turbines, and because there is an explicit requirement from the manufacturers of wind turbines that the bearings shall be able to cope with low-load/high speed operating conditions, there is an important requirement to provide suitable bearings.

Known solutions for reducing the risk of slippage and the damage that can be caused by such slippage include:- coatings of the bearing surfaces of the rollers and/or raceways, and bearing rollers and cages that are guided, supported and driven by an inner bearing ring.

The present invention seeks to provide a roller bearing assembly having an improved ability to operate without undue damage under conditions such as those described above. In accordance with one aspect of the present invention there is provided a roller bearing assembly comprising a plurality of bearing rollers located between confronting bearing surfaces, said bearing surfaces being rotatable one relative to the other about the rotational axis of the bearing, at least one of said bearing surfaces comprising an annular abutment surface which restricts movement of the rollers in an axial direction parallel with the rotational axis of each roller, and said bearing assembly comprising biasing means which acts in a direction parallel with said axis of rotation of the rollers to urge the bearing rollers against said annular abutment surface.

The invention is particularly applicable to a roller bearing assembly of the type which, in use, is loaded primarily in a radial direction, the bearing thus comprising bearing rollers located radially between the radially inner and outer bearing surfaces as considered relative to the rotational axis of the bearing, and having said biasing means providing a force which acts in an axial direction relative to said axis of rotation. In a bearing of this type the abutment surface acts to restrain movement of the bearing rollers in an axial direction parallel with the axis of the bearing.

The biasing means and abutment surface may each be associated with a common one of said confronting bearing surfaces, thereby to rotate in unison with one another and said bearing surface. Alternatively, however, the biasing means may be associated with a first of said confronting bearing surfaces and the annular abutment surface may be associated with the other of said confronting bearing surfaces.

In a further alternative each of the inner and outer bearing surfaces has a roller driver associated therewith, each roller driver being non-rotatably mounted relative to the bearing surface with which it is associated. Preferably the two roller drivers are positioned to bear against opposite ends of the rollers thereby to tend to create a force moment that causes each roller to be maintained in a rotational mode about its own axis when the bearing surfaces rotate one relative to the other.

The bearing surfaces may be provided by a pair of bearing rings in conventional manner, for example inner and outer bearing rings in the case of a radial roller bearing. Alternatively one or each of said bearing surfaces may be defined by the surface of another component, such as a shaft or toothed gear, in an integrated type construction in which said other component performs an additional function.

Preferably the biasing means is provided in a manner in which it rotates in unison with that bearing surface which is subject to a varying speed of rotation. The present invention envisages that typically the biasing means may be associated with the radially inner bearing surface in the case of a radial type bearing, that radially inner bearing surface being defined either by the inner ring of a bearing, or, in the case of an integrated construction, by, for example, a shaft rotatably mounted in the housing of a gearbox.

In the case of a bearing assembly of the type comprising a bearing ring mounted on a supporting component such as a rotatable shaft or a gear unit housing, the biasing means may be mounted either on the bearing ring or on the supporting component.

The bearing assembly may comprise bearing rollers which run between radially inner and radially outer bearing surfaces, and one of said bearing surfaces may be provided with, or have associated therewith, said annular abutment, and the other bearing surface may be provided with, or have associated therewith, a pair of abutment surfaces which provide positive axial location of the bearing rollers relative to said other bearing surface.

The invention is of particular applicability to bearing rollers of the cylindrical type, but may also be employed in the case of taper type roller bearings. The biasing means may comprise an element of resilient material, or an element of a material which is not necessarily substantially resilient, but is shaped to be deformable in said axial direction thereby to provide a biasing force. The biasing means may comprise a substantially non-resilient element provided in combination with a resilient element, such as, for example, one or a plurality of compression rings. Other types of biasing means, such as leaf springs, may also be employed.

The bearing preferably is of the type which comprises a cage, in contrast to a full complement cage-less type bearing.

The invention provides also a multi-stage gear unit in which at least one of a high speed or intermediate speed shaft is supported by a roller bearing assembly of a type in accordance with the present invention.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which: -

Figure 1 is a cross-section of part of a roller bearing assembly in accordance with a first embodiment of the present invention;

Figures 2 to 4 are views similar to that of Figure 1 of roller bearing assemblies in accordance with other embodiments of the present invention, and

Figures 5 to 8 show variations of the embodiments of figures 1 to 4.

Figure 1 shows part of a radial type roller bearing assembly 10 comprising an outer bearing ring 11 , an inner bearing ring 13, and one of a plurality of cylindrical bearing rollers 12 positioned between the confronting bearing surfaces 14, 15 of the inner and outer rings.

The inner ring is mounted on a shaft 16 and is formed at one axial end region 17 with an annular abutment face 18 against which an end face of the bearing roller 2 may be urged to bear.

The other end of the bearing inner ring 13 has associated therewith biasing means in the form of a roller driver 19 comprising an annular element of elastomeric material which is adhered to the shaft 16. The roller driver has, in this embodiment, a part-circular cross-sectional shape whereby a lip portion 20 is caused to bear against an end face of the bearing roller in consequence of deformation of the flexible, curved intermediate section 21 of the roller driver lying between the lip region 20 and an inner portion 22 secured to the shaft 16.

In this embodiment of the invention the outer bearing ring 11 comprises a pair of annular abutment surfaces 23, 24 which restrain axial movement of the bearing roller, about the axis of rotation of that roller.

In use of the roller bearing assembly 10, the action of the roller driver ensures that most of the bearing rollers are always maintained in contact with the rotating bearing inner ring 13. In consequence, and in combination with the action of a bearing cage in which the bearing rollers are mounted, even though a bearing roller at some positions of rotation of the bearing may not be in contact with each of the inner and outer bearing rings, it is nevertheless ensured that the train of bearing rollers and bearing cage is maintained in a rotational mode about the shaft axis. In consequence good lubrication is maintained and the risk of surface damage in the event of changing load conditions is reduced as compared particularly with a conventional construction in which it is possible for an individual bearing roller to lie in an idle, non-rotating state out of contact with each of the inner and outer bearing surfaces.

Figure 2 shows an alternative construction in which a roller driver 30 is mounted upon a bearing inner ring 31.

Figure 3 shows a construction in which a roller driver 40 of substantially non- deformable material provides an axial biasing force on a bearing roller 45 by virtue of a plurality of circumferentially spaced compression springs 41 positioned between a rear face 42 of the roller driver and an annular retention ring 43 located in a groove in the shaft 44.

Figure 4 shows an alternative construction in which a retainer ring 52 is located in a groove provided in the bearing inner ring 55 thereby to provide an abutment against which compression springs 51 can act to cause a roller driver 50 of non-deformable material to bear against the bearing roller 54.

Whilst the embodiments of Figures 2 and 4 are of particular applicability to the construction of a new assembly such as a multi-stage gear unit, the embodiments of Figures 1 and 3 have particular suitability for retro-fit application to enable the operating capabilities of an existing assembly to be upgraded.

In the following embodiments of the invention a roller driver 63 installed on a rotating part 64 (see fig.5), such as the aforedescribed shaft, is combined with an additional flexible roller driver 60 installed on a non-rotating part 65, such as a gear box housing. This additional driver touches the roller end face 62 at the end opposite the rotating roller driver 63. It causes the rollers 66 to touch the additional roller driver 60 and an opposite annular abutment 67 on the outer ring. The rollers are therefore driven by a couple of forces acting on opposite end faces, and this couple of forces creates a moment that ensures that each roller is also maintained in rotational mode about its own axis. Figures 5 to 8 show constructions which are respectively variations of the constructions of figures 1 to 4. In figure 5 the roller driver 60 is secured between a bearing outer ring and shoulder of a gearbox housing 65. In figure 6 the roller driver 70 is secured to the bearing outer ring 71. Figures 7 and 8 show respectively an additional roller driver 80,81 corresponding to that of figures 5 and 6 and secured in figure 7 betweep a housing 82 and outer ring 83, and to an outer ring 84 in figure 8.

Claims

1. A roller bearing assembly (10) comprising a plurality of bearing rollers (12) located between confronting bearing surfaces (14,15), said bearing surfaces being rotatable one relative to the other about the rotational axis of the bearing, at least one of said bearing surfaces comprising an annular abutment surface (18) which restricts movement of the rollers in an axial direction parallel with the rotational axis of each roller, and said bearing comprising biasing means (19) which acts in a direction parallel with said axis of rotation of the rollers to urge the bearing rollers against an annular abutment surface (18).

2. A roller bearing assembly according to claim 1 , wherein the bearing is loaded primarily in a radial direction, and said biasing means (19) provides a force which acts in an axial direction parallel with the axis of the bearing.

3. A roller bearing assembly according to claim 1 or claim 2, wherein the abutment surface (18) acts to restrain movement of bearing rollers (12) in an axial direction parallel with the axis of the bearing.

4. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means (19) and abutment surface (18) are associated with a common one of said confronting bearing surfaces (14,15), thereby to rotate in unison with one another and said bearing surface.

5. A roller bearing assembly according to any one claimsl to 3, wherein the biasing means (19) is non-rotatable relative to a first (14) of said confronting bearing surfaces and the annular abutment surface (23) is non-rotatable relative to the other (15) of said confronting bearing surfaces.

6. A roller bearing assembly according to any one of the preceding claims, wherein the bearing surfaces are defined by a pair of bearing rings (11 ,13).

7. A roller bearing assembly according to any one of claims 1 to 5, wherein one or each of said bearing surfaces is defined by the surface of a component of an integrated type construction in which said other component performs an additional function.

8. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means (19) rotates in unison with that bearing surface (14) which is subject, in use, to a varying speed of rotation.

9. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means (19) is associated with the radially inner bearing surface (14) of a radial type bearing.

10. A roller bearing assembly according to any one of the preceding claims, wherein the bearing comprises biasing means (30) mounted on a bearing ring (31 ).

11. A roller bearing assembly according to any one of the preceding claims, wherein the bearing comprises bearing rollers (12)which run between radially inner and radially outer bearing surfaces (14,15), and one (14) of said bearing surfaces is provided with or has associated therewith said annular abutment (19) and the other bearing surface (15) is provided with, or has associated therewith, a pair of abutment surfaces (22,23)which provide positive axial location of the bearing rollers relative to said other bearing surface (15).

12. A roller bearing assembly according to any one claims 1 to 10, wherein an additional biasing means (60) is provided and said two biasing means (60,63) are arranged each to be movable in unison with a respective one of said confronting bearing surfaces.

13. A roller bearing assembly according to claim 12, wherein one (60) of said two biasing means acts on a first end of each of said rollers (66) and the other biasing means (63) acts on a second end of each of said rollers.

14. A roller bearing assembly according to any one of the preceding claims, wherein the bearing is of the type which comprises a cage.

15. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means(19) comprises an element of resilient material.

16. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means (19) comprises an element of a material which is not necessarily substantially resilient, but is shaped to be deformable in said axial direction thereby to provide a biasing force.

17. A roller bearing assembly according to any one of the preceding claims, wherein the biasing means (19) comprises a substantially non-resilient element (40) provided in combination with a resilient element (41 ).

18. A roller bearing assembly constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

19. A multi-stage gear unit in which at least one of a high speed or intermediate speed shaft is supported by, or comprises a part of, a roller bearing assembly of a type in according to any one of the preceding claims.

20. A multi-stage gear unit in accordance with claim 19, wherein a shaft of the gear unit provides one of the confronting bearing surfaces or means for locating biasing means.