Rolling bearing arrangement and wind turbine

Abstract

A rolling bearing arrangement (1), in particular in a wind turbine, comprises a bearing ring (3, 8) and a connection component (2, 5), a non-metal layer (6) being located between the bearing ring (3, 8) and the connection component (2, 5) and having a thickness variation.

Description

[0001] Rolling bearing arrangement and wind turbines

[0002] The invention relates to a rolling bearing assembly designed according to the preamble of claim 1, which has a non-metallic layer arranged between a bearing ring and a connecting component. Furthermore, the invention relates to a wind turbine with a rolling bearing assembly.

[0003] A rolling bearing assembly described in DE 42 14 655 A1 comprises several bearing rings, with an intermediate layer arranged between an outer ring and a component supported by the outer ring. The intermediate layer can be made of a thermally insulating plastic. Possible plastics mentioned are polyamide-imide and polyether ether ketone (PEEK). The rolling bearing assembly according to DE 42 14 655 A1 is intended for use in a motor vehicle.

[0004] US 2016 / 0090966 A1 concerns a rotor shaft assembly for a wind turbine. A coating within the rotor shaft assembly can serve to provide electrical insulation, corrosion protection, or reduce friction. Among other things, the possibility of coating rolling elements is mentioned.

[0005] Corrosion protection is also addressed in US 2018 / 0106294 A1, which also concerns a rolling bearing. In this case, a rust protection film can be applied, for example, to a stationary bearing surface. The rust protection film is intended to achieve a sacrificial anode effect.

[0006] EP 2 947 339 A1 lists plastic coatings such as PTFE and hard coatings such as DLC (diamond-like carbon) and hard chrome coatings as coating materials for a large bearing in a wind turbine. The rolling elements of the bearing described in EP 2 947 339 A1 roll on a rotor or stator without a separate bearing ring. A diamond coating is also mentioned in WO 2022 / 229359 A1, which also concerns a bearing unit of a wind turbine. In this case, a friction element provided with a diamond coating is clamped against the underside of a bearing ring.

[0007] Documents WO 2023 / 062144 A1 and WO 2023 / 062145 A1 disclose various main bearing assemblies for wind turbines. In both cases, a bearing ring has a positive locking element. Furthermore, the aforementioned documents list PTFE and DLC as possible coating materials for a bearing ring or a shaft.

[0008] The use of form-fitting components as a measure against bearing ring creep, which could lead to premature wear, is also recommended in documents DE 10 2019 118 810 A1 and DE 10 2013 220 834 A1. Both documents also address the prevention of axial displacement of a bearing ring.

[0009] Regarding the topic of creep of rolling bearing rings, reference is also made to the following publication:

[0010] Research Report FVA 479 IV, IGF No. 16985 BR, Research Association for Drive Technology, Remedial Measures for Rolling Bearing Migration, Definition and Design of Structural and Tribological Remedial Measures Against Tangential Migration of Rolling Bearing Rings, 2015

[0011] As part of the research project, various solutions, including form-fitting ones, were developed and their effectiveness was investigated experimentally and using complex 3D FE analyses. A steel intermediate ring placed between a bearing and a surrounding structure was investigated both experimentally and experimentally.

[0012] DE 10 2012 221 739 A1 describes a bearing assembly intended for use in a wind turbine, which comprises at least one rolling bearing, namely a tapered roller bearing. The rolling bearing has a first bearing connected to the rotor of the wind turbine and a second bearing connected to a housing. The first bearing ring connected to the rotor has a cylindrical seating surface with which it sits on a cylindrical section of the rotor. According to DE 10 2012 221 739 A1, the cylindrical seating surface is machined by a hard turning process. Furthermore, it is proposed to arrange a ring element made of fiber-reinforced plastic between an end face of the same bearing ring and an end face of a shoulder of the rotor, which end face is designed for axial contact.

[0013] The invention is based on the object of further developing rolling bearing assemblies which have at least one non-metallically coated bearing component, for example a coated bearing ring, in particular with regard to the aspect of rolling body-induced and structure-induced microslip compared to the cited prior art, wherein, among other things, suitability for wind turbines is sought.

[0014] This object is achieved according to the invention by a rolling bearing assembly having the features of claim 1. The rolling bearing assembly is particularly suitable for use in a wind turbine according to claim 10 and comprises a bearing ring and a connecting component, wherein a non-metallic layer is located between the bearing ring and the connecting component. The layer can be part of the bearing ring and has a thickness profile according to claim 1.

[0015] The profiling of the non-metallic layer, especially the plastic layer, serves primarily to compensate for load-related deformations and thus to even out the loads acting on bearing components. Compared to the metallic base material of the bearing components, especially the bearing ring, the non-metallic layer is significantly more elastically compliant. This enables the layer to absorb micro-movements that occur during operation of the rolling bearing assembly, which can be caused, among other things, by deformation of the bearing ring caused by the rolling elements. This would already constitute a measure against bearing ring creep without profiling the layer.

[0016] The invention is based on the consideration that during operation of a rolling bearing, in particular a large-diameter bearing, different areas of a bearing ring as well as a connecting component connected to the bearing are subject to varying degrees of elastic deformation. If the metallic base body of the bearing ring is separated from the connecting component by a non-metallic layer, the unavoidable elastic deformations of the bearing ring and / or the connecting component result in different surface areas of the non-metallic layer experiencing varying degrees of surface pressure.

[0017] According to the application, this undesirable effect is counteracted by specifically reducing the thickness of the non-metallic layer in those areas where the highest surface pressures would otherwise be expected, i.e., with a completely uniform layer thickness. Reducing the layer thickness does not necessarily mean subsequently removing coating material. Rather, it is also possible to apply the coating material to the base material of the bearing ring in a non-uniform thickness during the coating process. The bearing ring to be coated can either be made of the same material or already have a metallic coating or surface treatment. Such a surface treatment can take the form of a bluing, for example.Depending on the geometric design chosen in the individual case and the loads occurring during operation, the profiling of the elastomer layer or other non-metallic layer on the bearing ring can also contribute to a reduction in edge loads. Depending on the rolling bearing design, the profiling of the non-metallic layer can mean a variation in thickness in different directions. If the rolling bearing arrangement is designed as a radial bearing, for example, the thickness of the non-metallic layer applied to the bearing ring can be non-uniform, particularly in the axial direction of the bearing ring. In this case, the layer thickness can increase from the center plane of the bearing ring towards its end faces. In other words: the plastic coating or other non-metallic, elastically flexible coating of the bearing ring has a thickening on the sides, next to the center plane of the bearing ring.In particular, such thickenings are designed with mirror symmetry to the center plane of the bearing ring. This applies particularly to cases in which the bearing ring as a whole is designed with mirror symmetry to its center plane. If, however, such mirror symmetry is not present, as is the case, for example, with bearing rings of angular contact roller bearings, asymmetrically designed variations in the thickness of the non-metallic layer can also be considered as an alternative to symmetrical thickness profiling. For example, in such a case, the thickening is particularly pronounced in the area of ​​the bearing ring where the thickness of the bearing ring, i.e., the difference between the outer and inner diameters, is maximum.

[0018] Thickening of the non-metallic layer, especially the plastic layer, is defined as the difference between the maximum and minimum layer thickness. This difference is, for example, at least 0.01% and a maximum of 0.3% of the bearing ring diameter, with this diameter being measured at the contact surface of the metallic base body of the bearing ring and the non-metallic layer. Regardless of the type of thickness profiling, the elastic modulus of the non-metallic layer is, for example, less than 25 GPa.

[0019] Alternatively or in addition to a variation in the thickness of the non-metallic layer in the axial direction of the bearing, a layer thickness variation in the circumferential direction of the bearing ring can be provided. According to a first group of embodiments, the layer thickness variation is stepped in the circumferential direction. A second group of embodiments, however, provides for a continuous layer thickness variation in the circumferential direction of the bearing ring. In both cases, a region of reduced layer thickness extends, for example, over 20° to 160° around the circumference of the bearing ring. The difference between the maximum layer thickness and the minimum layer thickness can, for example, be at least 0.02% and a maximum of 0.7% of the bearing ring diameter, again measured at its contact surface with the non-metallic layer.

[0020] Various variants of the rolling bearing assembly provide for the non-metallic, thickness-profiled layer, which separates a metallic component of the bearing ring from the likewise metallic connecting component, to be designed as a coating. The coating can be, for example, a powder coating or a lubricating coating. Compared to a powder coating, which has a high coefficient of friction, a lubricating coating allows for a greater degree of micromovement. This allows transfer films to form, which also prevent bearing seat damage. Regardless of the material from which the non-metallic layer with its uneven thickness is constructed, its electrical insulation effect represents another desirable property.

[0021] Several embodiments of the invention are explained in more detail below with reference to a drawing. In the drawings:

[0022] Fig. 1 shows a first embodiment of a rolling bearing arrangement with a bearing ring which has a non-metallic coating with a non-uniform layer thickness,

[0023] Fig. 2 and 3 further rolling bearing arrangements, each having a non-uniformly coated bearing ring.

[0024] The following explanations refer to all exemplary embodiments, unless otherwise stated. Parts that correspond to one another or have essentially the same function are identified by the same reference numeral in all figures. A rolling bearing assembly, designated overall by the reference numeral 1, has at least one bearing ring 3, 8 and a plurality of rolling elements 4. On an inner or outer circumferential surface 7, 9 of the bearing ring 3, 8 - more precisely: on a surface of the metallic base body of the bearing ring 3, 8 - there is a non-metallic layer 6 that contacts a connecting component 2, 5 of the bearing assembly 1. In the present case, the non-metallic layer 6 is a plastic layer. Alternatively, an elastomer layer could be provided as the non-metallic layer 6, for example.

[0025] In all embodiments, the non-metallic layer 6 has a thickness profile. The minimum thickness of the non-metallic layer 6 is always designated dmin, and the maximum thickness is designated dmax. Generally, the non-metallic layer 6 is an electrically insulating layer.

[0026] In the embodiment according to Figure 1, the bearing ring 3 is an inner ring. The bearing arrangement 1, i.e. rolling bearing arrangement, is in this case designed as a ball bearing, wherein the connecting component 2 is in the form of a shaft and the rolling elements 4, i.e. balls, roll directly in a housing 5 as a further connecting component. An outer ring (not shown) in which the rolling elements 4 roll could also be present. With reference to the arrangement according to Figure 1, the axis of rotation of the bearing arrangement 1 lies above the visible components 2, 3, 5 in a horizontal orientation. A vertical straight line passing through the center of the rolling element 4 visible in Figure 1 is accordingly radially aligned. The pressure line passing through the rolling element 4 lies on this straight line.

[0027] The radial load on the bearing ring 3 of the rolling bearing assembly 1 according to Figure 1 is greatest in the center between the two end faces of the bearing ring 3. If the non-metallic layer 6 had a uniform thickness, this would mean that the non-metallic layer 6 is compressed at least slightly more strongly in the region of the center plane of the bearing assembly 1, i.e., in the plane orthogonal to the image plane and intersecting the center of the rolling element 4, in the load zone of the bearing assembly 1 than in the vicinity of the end faces of the bearing ring 3.

[0028] This undesirable effect is minimized in the bearing assembly 1 in that the non-metallic layer 6 has its minimum thickness dmin in its center, i.e., in the region of the center plane of the bearing assembly 1, and its maximum thickness dmax at its two edges, i.e., at the transitions between the circumferential surface 7 and the end faces of the bearing ring 3. This results in a concave profile of the non-metallic layer 6. In addition, in the embodiment according to Figure 1, the end faces of the bearing ring 3 are also partially coated with the electrically insulating, elastically flexible non-metallic layer 6.

[0029] If a load is applied in the radial direction via the rolling elements 4 to the bearing ring 3 in the center plane of the bearing arrangement 1, this initially leads to a compression of the non-metallic layer 6 in the two edge regions of the cylindrical circumferential surface 7 of the bearing ring 3. At the same time, the originally cylindrical circumferential surface 7 of the bearing ring 3, on which the non-metallic layer 6 is located, experiences a minimal curvature, so that it assumes a convex shape. Even with a minimal extent of this change in shape, this, together with the compression of the two outer regions of the non-metallic layer 6, contributes to the non-metallic layer 6 coming into contact with the surface of the connecting component 2 across its entire width as the radial force continues to increase. Ultimately, a state is reached in which the non-metallic layer 6 is subjected to at least approximately uniform mechanical stress across its entire width.Due to its uniform loading, the non-metallic layer 6 is able to absorb micro-movements of the bearing ring 3 relative to the connecting component 2 in a particularly low-wear and at the same time highly efficient manner and thus counteracts bearing ring creep.

[0030] In the exemplary embodiments according to Figures 2 and 3, the bearing ring 8 coated with a non-metallic layer 6 is an outer ring. In these cases, the connecting component 5 is present as the housing of the bearing assembly 1. Overall, the bearing assemblies 1 according to Figures 2 and 3 are designed as roller bearings, with the rotational axis oriented perpendicular to the image plane.

[0031] In the embodiment according to Figure 2, the non-metallic layer 6 has a thickness gradation 10 in the circumferential direction. The non-metallic layer 6 is applied to the entire outer circumferential surface, designated 9, of the bearing ring 8, the outer ring. Radial loads occur predominantly in the lower region of the bearing ring 8 and thus also of the non-metallic layer 6. The thickness gradations 10 are also located in the lower region of the bearing assembly 1, whereby a symmetry with a vertical mirror plane passing through the center plane of the bearing assembly 1 is ensured. The angle to be measured in the circumferential direction between the thickness gradations 10, which are located on both sides of the mirror plane, is designated α. Within this angle α, the non-metallic layer 6 has the minimum thickness dmin; outside the angle α, which in the present case is significantly less than 90°, namely approximately 40°, the maximum thickness dmax of the non-metallic layer 6 is present.

[0032] The embodiment according to Figure 3 differs from the embodiment according to Figure 2 in that, instead of thickness gradations, there are continuous transitions between the maximum thickness dmax and the minimum thickness dmin. In this case, too, the minimum layer thickness dmin of the non-metallic layer 6 is present at the lowest point of the bearing arrangement 1, i.e., the point most subject to gravitational forces. The angle (360° - a) at which the maximum layer thickness dmax is consistently present is approximately 270° in the case of Figure 3.

[0033] In both the case of Figure 2 and the case of Figure 3, the targeted reduction in the layer thickness of the non-metallic layer 6 in the load zone, compared to a fictitious uniform layer thickness dmax over the entire circumference of the bearing ring 8, prevents excessive deformations in the load zone of the rolling bearing arrangement 1, which has a positive effect on the service life of the non-metallic layer 6 and thus of the entire bearing arrangement 1. In a manner not shown, the variation in the layer thickness in the circumferential direction according to Figure 4 can be combined with the layer thickness variation in the axial direction, as illustrated in Figure 1. In this case, the layer thickness, which is to be measured in the center plane of the bearing arrangement 1, can vary in the circumferential direction of the bearing ring 3, 8 and, in addition, a thickness of the non-metallic layer 6 of the bearing ring 3, 8 that changes in the axial direction can be provided.This means that the entire non-metallic layer 6 placed in or around the base body of the bearing ring 3, 8 has the shape of a shallow groove, the contour of which changes along the circumference of the bearing ring 3, 8. In this case, the thickness of the non-metallic layer 6, measured in the two edge regions of the groove-shaped non-metallic layer 6, may also be non-uniform in the circumferential direction of the bearing ring 3, 8.

[0034] Furthermore, it is possible to coat both the inner ring 3 and the outer ring 8 with a non-metallic layer 6, in particular a plastic layer, which has a thickness profile. Regardless of the exact type of profiling, the non-metallic layer 6 is an electrically insulating layer. In the case of several such layers 6 integrated into the bearing assembly 1, the different layers 6 can be constructed from different materials, in particular materials with different elastic properties. For example, the connecting component 5 with a lower dimensional stability contacts a more elastically flexible, on average thicker non-metallic layer 6 than the comparatively rigid connecting component 4.The bearing arrangement 1 according to Figure 1, like the bearing arrangements 1 according to Figures 2 and 3, is particularly suitable for use in wind turbines, for example in a gearbox of a wind turbine. List of reference symbols.

[0035] 1 rolling bearing arrangement

[0036] 2 connection component, shaft

[0037] 3 Bearing, inner ring

[0038] 4 rolling elements

[0039] 5 Connection component, housing

[0040] 6 non-metallic layer

[0041] 7 Circumferential surface of the inner ring

[0042] 8 Bearing ring, outer ring

[0043] 9 Circumferential surface of the outer ring

[0044] 10 Thickness gradation a Angle dmin minimum thickness dmax maximum thickness

Claims

Patent claims 1 . Rolling bearing arrangement (1), comprising a bearing (3, 8) and a connecting component (2, 5), wherein a non-metallic layer (6) is located between the bearing (3, 8) and the connecting component (2, 5), characterized in that the non-metallic layer (6) has a thickness profile.

2. Rolling bearing arrangement (1) according to claim 1, characterized in that the thickness of the layer (6) is non-uniform in the axial direction of the bearing ring (3, 8), increasing from the center plane of the bearing ring (3, 8) towards its end faces.

3. Rolling bearing arrangement (1) according to claim 2, characterized in that the difference between the maximum layer thickness (dmax) and the minimum layer thickness (dmin) is at least 0.01 %o and at most 0.3 %o of the bearing ring diameter, to be measured at the contact surface with the non-metallic layer (6).

4. Rolling bearing arrangement (1) according to one of claims 1 to 3, characterized by a modulus of elasticity of the non-metallic layer (6) of less than 25 GPa.

5. Rolling bearing arrangement (1) according to one of claims 1 to 4, characterized in that the non-metallic layer (6) has a layer thickness variation in the circumferential direction of the bearing ring.

6. Rolling bearing arrangement (1) according to claim 5, characterized in that the layer thickness variation is stepped.

7. Rolling bearing arrangement (1) according to claim 5, characterized by a continuous layer thickness variation in the circumferential direction of the bearing ring (3, 8).

8. Rolling bearing arrangement (1) according to one of claims 5 to 7, characterized in that a region of reduced layer thickness extends over an angle (α) of at least 20° and at most 160° on the circumference of the bearing ring (3, 8), the difference between the maximum layer thickness (dmax) and the minimum layer thickness (dmin) being at least 0.02 %o and at most 0.7 %o of the bearing ring diameter, to be measured at the contact surface with the non-metallic layer (6).

9. Rolling bearing arrangement (1) according to one of claims 1 to 8, characterized in that the non-metallic layer (6) is designed as a lacquer layer, in particular a sliding or powder lacquer layer.

10. Wind turbine comprising at least one rolling bearing arrangement (1) according to claim 1.

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