Rolling bearing assemblies and wind turbine generator sets

Abstract

A rolling bearing assembly (1), particularly for wind turbine generator sets, includes a bearing ring (3,8) and a connecting member (2,5), wherein a non-metallic layer (6) having a thickness distribution is disposed between the bearing ring (3,8) and the connecting member (2,5).

Description

Technical Field

[0001] This invention relates to a rolling bearing assembly configured according to the preamble of claim 1, wherein a non-metallic layer is disposed between the bearing ring and the connecting member. Furthermore, this invention also relates to a wind turbine generator having this rolling bearing assembly. Background Technology

[0002] The rolling bearing assembly described in DE 42 14 655 A1 includes a plurality of bearing rings, wherein an intermediate layer is disposed between the outer ring and the component carried thereon. This intermediate layer may be formed of a thermally insulating plastic. Examples of possible plastics include polyimide and polyetheretherketone (PEEK). The rolling bearing assembly according to DE 42 14 655 A1 is envisioned for use in motor vehicles.

[0003] US 2016 / 0090966 A1 relates to a rotor shaft assembly for a wind turbine. The coating within the rotor shaft assembly can serve purposes such as electrical insulation, corrosion protection, or friction reduction. The document also mentions the possibility of coating the rolling elements.

[0004] US 2018 / 0106294 A1 also relates to rolling bearings and discusses corrosion prevention. In this case, a rust-preventive film can be applied, for example, to a fixed bearing surface. The rust-preventive film is intended to achieve a sacrificial anode effect.

[0005] In EP 2 947 339 A1, plastic coatings (such as PTFE) and hard coatings (such as DLC (diamond-like carbon) and hard chrome coatings) are listed as coating materials for large bearings of wind turbine generators. The rolling elements of the bearings described in EP 2 947 339 A1 roll on the rotor or stator without separate bearing rings.

[0006] WO 2022 / 229359 A1 also relates to bearing units of wind turbine generators and mentions diamond coating. In this case, it is envisioned that a friction element with a diamond coating is pressed against the bottom surface of the bearing ring.

[0007] Documents WO 2023 / 062144 A1 and WO 2023 / 062145 A1 disclose various main bearing arrangements for wind power installations. In both cases, the bearing rings are equipped with form-locking elements. Furthermore, in the aforementioned documents, PTFE and DLC are also listed as possible coating materials for the bearing rings or shafts.

[0008] In DE 10 2019 118 810 A1 and DE 10 2013 220 834 A1, it is also recommended to use form-locking components to suppress bearing ring migration, which can lead to premature wear. Both of these documents also address preventing axial displacement of the bearing rings.

[0009] For further information on the topic of rolling bearing ring migration, please refer to the following publications: Research report FVA 479 IV, IGF number 16985 BR, German Association for Transmission Technology (FVA), "Remedies for Rolling Bearing Misalignment: Definition and Design of Structural and Tribological Remedies for Tangential Misalignment of Rolling Bearing Rings", 2015.

[0010] In this research project, several solutions (including a form-locking scheme) were developed, and their effectiveness was investigated through experiments and complex three-dimensional finite element analysis. A steel intermediate ring positioned between the bearing ring and the surrounding structure was studied through simulation and experiments.

[0011] DE 10 2012 221 739 A1 describes a bearing arrangement for a wind power unit, comprising at least one rolling bearing, namely a tapered roller bearing. The rolling bearing includes a first bearing ring connected to the rotor of the wind power unit and a second bearing ring connected to the housing. The first bearing ring connected to the rotor has a cylindrical seat surface, by means of which it is mounted on a cylindrical section of the rotor. According to DE 10 2012 221 739 A1, it is envisioned that the cylindrical seat surface be machined by a hard turning process. Furthermore, it is proposed to place a fiber-reinforced plastic annular element between one end face of the bearing ring and the end face of a step formed by the rotor for axial support. Summary of the Invention

[0012] The objective of this invention is to improve upon the prior art, particularly in terms of rolling element-induced and structure-induced microslip, for rolling bearing assemblies having at least one non-metallic coated bearing component (e.g., coated bearing ring), while simultaneously seeking its applicability to wind turbine generator sets.

[0013] Therefore, the present invention is achieved by a rolling bearing assembly having the features described in claim 1. This rolling bearing assembly is particularly suitable for wind turbine generator sets according to claim 10, and includes a bearing ring and a connecting member, wherein a non-metallic layer is disposed between the bearing ring and the connecting member. This layer may be part of the bearing ring and has a thickness distribution according to claim 1.

[0014] The thickness distribution of non-metallic layers (especially plastic layers) is particularly useful for compensating for shape changes caused by loads, thereby homogenizing the loads acting on bearing components. Compared to the metallic substrate of bearing components (especially bearing races), non-metallic layers are significantly more compliant in terms of elasticity. Therefore, this layer can absorb the minute relative movements generated during the operation of rolling bearing assemblies, which can be partly attributed to bearing race deformation caused by rolling elements; even without a thickness distribution in this layer, this already constitutes a measure to suppress bearing race migration.

[0015] This invention is based on the following consideration: During the operation of rolling bearings (especially large bearings), different areas of the bearing race and the connecting elements connected to it will experience different degrees of elastic deformation. If the metal matrix of the bearing race is separated from the connecting elements by a non-metallic layer, the unavoidable elastic deformation of the bearing race and / or the connecting elements will cause different surface areas of the non-metallic layer to experience different degrees of surface pressure.

[0016] To overcome this undesirable effect, this application achieves this by selectively reducing the thickness of the non-metallic layer in areas where the highest surface pressure would occur if the thickness were perfectly uniform. This reduction in thickness does not necessarily mean subsequent removal of the coating material; rather, it means applying the coating material to the bearing ring substrate with a non-uniform thickness during the coating process. The bearing ring to be coated can be integral with the material or can have already undergone a metal coating or surface treatment. For example, the surface treatment could be a blackening process. Depending on the specific geometry and operating load, the thickness distribution of the elastomeric layer or other non-metallic layer on the bearing ring can also help reduce edge loads.

[0017] The thickness distribution of the non-metallic layer can vary in different directions depending on the type of rolling bearing. For example, when the rolling bearing assembly is configured as a radial bearing, the thickness of the non-metallic layer applied to the bearing ring can be non-uniform in the axial direction of the bearing ring. In this case, the layer thickness can be increased from the center plane of the bearing ring towards its end face. In other words, the plastic coating or other non-metallic, flexible coating of the bearing ring has thickened portions on both sides of the center plane of the bearing ring. In particular, these thickened portions are mirror-symmetrical with respect to the center plane of the bearing ring. This is especially applicable to bearing rings that are mirror-symmetrical with respect to their center plane as a whole. When such mirror symmetry does not exist (e.g., the bearing ring of a skew roller bearing), in addition to a symmetrical thickness distribution, asymmetrical variations in the thickness of the non-metallic layer can also be considered. For example, in this case, the thickened portions are particularly noticeable in the region where the bearing ring thickness (i.e., the difference between the outer and inner diameters) is greatest.

[0018] The "thickness" of a non-metallic layer (especially a plastic layer) refers to the difference between the maximum and minimum layer thickness. This difference is, for example, at least 0.01‰ and at most 0.3‰ of the bearing ring diameter, which should be measured at the interface between the bearing ring's metal substrate and the non-metallic layer. Regardless of the type of thickness distribution, the elastic modulus of the non-metallic layer is, for example, less than 25 GPa.

[0019] In addition to, or instead of, varying the non-metallic layer thickness in the axial direction of the bearing, a variation in layer thickness can also be provided in the circumferential direction of the bearing ring. According to one set of embodiments, the circumferential layer thickness variation is formed in a stepped manner. According to another set of embodiments, a continuous layer thickness variation is provided in the circumferential direction of the bearing ring. In both cases, the region of reduced layer thickness extends, for example, from 20° to 160° along the circumference of the bearing ring. The difference between the maximum and minimum layer thickness is, for example, at least 0.02‰ and at most 0.7‰ of the bearing ring diameter, and its measurement is also performed at the contact surface between the bearing ring and the non-metallic layer.

[0020] Various variations of the rolling bearing assembly of the present invention are provided, in which a non-metallic layer with a thickness distribution is constructed as a varnish layer, separating the metal components of the bearing ring from the connecting components, which are also metal. This varnish layer can be, for example, a powder coating or a sliding varnish layer. Compared to a powder coating with a higher coefficient of friction, a sliding varnish layer allows for greater relative movement. This allows for the formation of a transfer film, which also helps prevent damage to the bearing housing. Regardless of the material of the non-metallic layer with its uneven thickness, its electrical insulation is another desirable characteristic. Attached Figure Description

[0021] Several embodiments of the present invention will be further described below with reference to the accompanying drawings. The drawings show: Figure 1 shows a first embodiment of a rolling bearing assembly, wherein the bearing rings have a non-metallic coating with a non-uniform thickness. Figures 2 and 3 show further rolling bearing assemblies, each with a bearing ring that is unevenly coated. Detailed Implementation

[0022] Unless otherwise stated, the following description applies to all embodiments. In all the drawings, parts that are identical or have the same function are labeled with the same reference numerals.

[0023] The rolling bearing assembly, generally indicated by reference numeral 1, includes at least one bearing ring 3, 8 and a plurality of rolling elements 4. A non-metallic layer 6 is disposed on the inner or outer circumferential surfaces 7, 9 of the bearing rings 3, 8—more precisely, on the metal substrate surfaces of the bearing rings 3, 8—and this non-metallic layer 6 contacts a connecting component 2, 5 of the rolling bearing assembly 1. In this embodiment, the non-metallic layer 6 is a plastic layer. Alternatively, an elastomer layer may also be used as the non-metallic layer 6, for example.

[0024] In all embodiments, the non-metallic layer 6 has a thickness distribution. The minimum thickness of the non-metallic layer 6 is denoted as d in all cases. min The maximum thickness is denoted as d. max Generally speaking, the non-metallic layer 6 is an electrically insulating layer.

[0025] exist Figure 1 In the illustrated embodiment, bearing ring 3 is the inner ring. The rolling bearing assembly 1 (i.e., the rolling bearing assembly) is configured as a ball bearing in this case, wherein the connecting member 2 is a shaft, and the rolling elements 4 (i.e., balls) roll directly within the housing 5, which serves as another connecting member. Alternatively, an outer ring (not shown) may be present, in which the rolling elements 4 roll. Figure 1 In the arrangement shown, the axis of rotation of the rolling bearing assembly 1 is horizontally oriented above the visible components 2, 3, and 5. (By...) Figure 1 The vertical line extending from the center of the rolling element 4 shown is therefore radially oriented. The pressure line passing through the rolling element 4 lies on this line.

[0026] Figure 1 The bearing ring 3 of the rolling bearing assembly 1 shown in the diagram experiences the greatest radial load at the midpoint between its two end faces. If the non-metallic layer 6 has a uniform thickness, this means that in the central plane region of the rolling bearing assembly 1 (i.e., the plane orthogonal to the illustrated plane and passing through the center of the rolling element 4), in the load area of ​​the rolling bearing assembly 1, the non-metallic layer 6 will experience at least stronger compression than near the end face of the bearing ring 3.

[0027] In the rolling bearing assembly 1, this undesirable effect is minimized by ensuring that the non-metallic layer 6 has a minimum thickness d in its central part (i.e., the central plane region of the rolling bearing assembly 1). min Its maximum thickness d is located at its two edges (i.e., the transition area between the circumferential surface 7 and the end face of the bearing ring 3). max This results in a concave thickness distribution for the non-metallic layer 6. Furthermore, in Figure 1 In the embodiment shown, the end face of the bearing ring 3 is also partially covered with an electrically insulating, elastic and flexible non-metallic layer 6.

[0028] When a load is applied radially to the bearing ring 3 via the rolling elements 4 on the central plane of the rolling bearing assembly 1, initially, the non-metallic layer 6 is compressed on both sides of the cylindrical circumferential surface 7 of the bearing ring 3. Simultaneously, the originally cylindrical circumferential surface 7 of the bearing ring 3 (on which the non-metallic layer 6 is disposed) develops a slight bulge, becoming convex. Even if this deformation is small, the combined effect of this deformation and the compression of the two outer regions of the non-metallic layer 6 causes the non-metallic layer 6 to contact the surface of the connecting member 2 across its entire width as the radial force further increases. Ultimately, a state is reached where the non-metallic layer 6 bears the mechanical load at least approximately uniformly across its entire width. Due to the uniform load distribution, the non-metallic layer 6 can absorb the small relative movements of the bearing ring 3 with the connecting member 2 in a particularly low-wear and efficient manner, thereby suppressing bearing ring slippage.

[0029] exist Figure 2 and Figure 3 In the illustrated embodiment, the bearing ring 8 coated with the non-metallic layer 6 is the outer ring. The connecting component 5 in this case is the housing of the rolling bearing assembly 1. Overall, Figure 2 and Figure 3 The rolling bearing assembly 1 shown is configured as a roller bearing, and its axis of rotation is oriented perpendicular to the plane shown in the figure.

[0030] exist Figure 2 In the arrangement shown, the non-metallic layer 6 has a thickness step 10 in the circumferential direction. The non-metallic layer 6 covers the entire outer circumferential surface 9 of the bearing ring 8 (i.e., the outer ring). Radial loads mainly occur in the lower region of the bearing ring 8, and thus mainly act on the non-metallic layer 6. The thickness step 10 is also located in the lower region of the rolling bearing assembly 1 and is symmetrically distributed with respect to a vertical mirror plane passing through the center plane of the rolling bearing assembly 1. The included angle measured in the circumferential direction between the thickness steps 10 located on both sides of the mirror plane is denoted as α. Within this included angle α, the non-metallic layer 6 has a minimum thickness d. min Outside of this included angle α (significantly less than 90° in this example, approximately 40°), the non-metallic layer 6 has its maximum thickness d. max .

[0031] Figure 3 The illustrated embodiments and Figure 2 The difference in the illustrated embodiment is that instead of using thickness steps, it uses the maximum thickness d. max With minimum thickness d min A continuous transition is set between them; at the same time, in this case, at the lowest point of the rolling bearing assembly 1 (i.e., the point where the load is greatest due to gravity), the minimum layer thickness d of the non-metallic layer 6 is... min It also exists. At Figure 3 In the case shown, the maximum layer thickness d is continuously maintained. max Angle (360°) α) is approximately 270°.

[0032] Whether Figure 2 The situation is still Figure 3 In this case, by selectively reducing the thickness of the non-metallic layer 6 in the load area, a layer thickness d consistent with the intended thickness across the entire circumference of the bearing ring 8 can be achieved. max In comparison, both methods can avoid excessive deformation in the load area, which has a positive impact on the lifespan of the non-metallic layer 6 and the entire rolling bearing assembly 1.

[0033] In a manner not shown, the layer thickness variation along the circumferential direction shown in Figure 4 can be compared with... Figure 1 The layer thickness variation along the axial direction is combined as shown. In this case, the layer thickness measured at the center plane of the rolling bearing assembly 1 can vary along the circumferential direction of the bearing rings 3 and 8, and the non-metallic layer 6 of the bearing rings 3 and 8 can also have a varying thickness in the axial direction. This means that the entire non-metallic layer 6 surrounding or covering the substrate of the bearing rings 3 and 8 is shallowly grooved, and its outline varies along the circumferential direction of the bearing rings 3 and 8. In this case, the thickness of the non-metallic layer 6 measured in the circumferential direction of the bearing rings 3 and 8 at the two edge regions of the grooved non-metallic layer 6 can also be non-uniform.

[0034] Furthermore, both the inner ring 3 and the outer ring 8 can be coated with a non-metallic layer 6 (especially a plastic layer) with a thickness distribution. Regardless of the specific form of its thickness distribution, the non-metallic layer 6 is an electrically insulating layer; when multiple such layers 6 are integrated in the rolling bearing assembly 1, the different layers 6 can be made of different materials, especially materials with different elastic properties. For example, the non-metallic layer 6 in contact with the connecting part 5, which has lower shape stability, can have greater elastic flexibility and be thicker on average than the non-metallic layer in contact with the more rigid connecting part 4. Figure 1 The rolling bearing assembly 1 shown and Figure 2 and Figure 3 The rolling bearing assembly 1 shown is particularly suitable for use in wind turbine generator sets, such as in the gearbox of a wind turbine generator set.

[0035] Explanation of reference numerals in the attached figures 1 Rolling bearing assembly 2. Connecting components, shaft 3. Bearing ring, inner ring 4 Rolling elements 5. Connecting components, housing 6 Non-metallic layer 7. Circumferential surface of the inner ring 8. Bearing ring, outer ring 9. The outer circumferential surface 10 Thickness Steps α angle dmin minimum thickness dmax is the maximum thickness.

Claims

1. A rolling bearing assembly (1), It includes a bearing ring (3, 8) and a connecting part (2, 5). Its features are, A non-metallic layer (6) is provided between the bearing rings (3, 8) and the connecting parts (2, 5). The non-metallic layer (6) has a thickness distribution.

2. The rolling bearing assembly (1) according to claim 1. Its features are, The thickness of layer (6) is not uniform in the axial direction of the bearing rings (3, 8). And it increases from the center plane of the bearing ring (3, 8) toward its end face.

3. The rolling bearing assembly (1) according to claim 2. Its features are, The difference between the maximum layer thickness (dmax) and the minimum layer thickness (dmin) shall be at least 0.01‰ and at most 0.3‰ of the bearing ring diameter. The diameter is measured at the surface in contact with the non-metallic layer (6).

4. The rolling bearing assembly (1) according to any one of claims 1 to 3. Its features are, The elastic modulus of the non-metallic layer (6) is less than 25 GPa.

5. The rolling bearing assembly (1) according to any one of claims 1 to 4. Its features are, The non-metallic layer (6) has a thickness variation in the circumferential direction of the bearing ring.

6. The rolling bearing assembly (1) according to claim 5. Its features are, The layer thickness variation is stepped.

7. The rolling bearing assembly (1) according to claim 5. Its features are, The bearing rings (3, 8) have a continuous layer thickness variation in the circumferential direction.

8. The rolling bearing assembly (1) according to any one of claims 5 to 7. Its features are, The angle (α) by which the area of ​​reduced layer thickness extends along the circumference of the bearing rings (3, 8) is at least 20° and at most 160°. The difference between the maximum layer thickness (dmax) and the minimum layer thickness (dmin) is at least 0.02‰ and at most 0.7‰ of the bearing ring diameter. The diameter is measured at the surface in contact with the non-metallic layer (6).

9. The rolling bearing assembly (1) according to any one of claims 1 to 8. Its features are, The non-metallic layer (6) is a paint layer, especially a sliding paint layer or a powder coating.

10. A wind turbine generator set, Includes at least one rolling bearing assembly (1) according to claim 1.

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