Rolling bearing arrangement and method for preloading a rolling bearing

Abstract

A rolling bearing arrangement (1), for example in a wind turbine, comprises at least one rolling bearing (4, 5) having a bearing ring (6, 9), which is axially supported on a surrounding component (3, 11, 12) via an elastic, three-dimensionally structured thermoset element (10).

Description

[0001] Rolling bearing arrangement and method for preloading a rolling bearing

[0002] The invention relates to a rolling bearing assembly in which a preload force acts in the axial direction of the bearing assembly. Furthermore, the invention relates to a method for preloading a rolling bearing.

[0003] WO 2022 / 229359 A1 describes a method for applying a bearing preload to a main bearing unit of a wind turbine. The main bearing unit comprises a bearing ring that is adjustable in the axial direction along a shaft to apply a bearing preload. The shaft, which acts as the ring carrier, has a thread, and a clamping ring designed as a shaft nut can be screwed against the bearing ring to apply the bearing preload.

[0004] Another bearing assembly with a preload device is disclosed in DE 10 2009 038 261 A1. In this case, an axial force is generated using a disc spring. The bearing assembly according to DE 10 2009 038 261 A1 is intended for use in a motor vehicle.

[0005] A preload device integrated into a bearing is described in DE 10 2014 204 101 A1. In this case, a preload element is arranged in a recess of a bearing ring. Thermosetting elastomer materials are proposed as materials for manufacturing the preload element.

[0006] According to DE 10 2006 010 655 B4, a seal of a rolling bearing is also designed as a means of preloading. For example, it is possible to design a sealing washer as a disc spring, which is attached to the inner or outer ring of the rolling bearing, whereby its spring force presses axially on the other bearing ring. An electrically insulating bearing ring for a rolling bearing described in DE 10 2010 015 155 A1 comprises polyamide as the insulation material, with the electrically insulating layer being approximately 20 to 200 micrometers thick. Between the electrically insulating layer and a base body of the bearing ring is an intermediate layer, which may be a roughened surface of the base body.

[0007] JP 2007-315585 A proposes the use of a polyamide 9T element to apply a radial force to a bearing ring of a rolling bearing during assembly. The polyamide 9T element is located in an annular groove on the outer peripheral surface of the bearing ring.

[0008] DE 10 2010 024 582 A1 discloses a rolling bearing with an insulating sleeve. The insulating sleeve has radially inwardly folded ribs on both sides that enclose the outer ring of the rolling bearing. The insulating sleeve serves not only to insulate the rolling bearing electrically but also acoustically.

[0009] DE 11 2016 000 858 T5 deals specifically with the rust protection properties of a rolling bearing. It proposes the use of a rust protection film designed as a porous film with a sacrificial anode effect.

[0010] 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 ring connected to the rotor of the wind turbine and a second bearing ring connected to a housing. The first bearing ring connected to the rotor has a cylindrical seating surface with which it sits on a section of the rotor. To prevent the bearing ring's susceptibility to cracking, DE 10 2012 221 739 A1 provides for the cylindrical seating surface to be machined by a hard turning process. Furthermore, it is provided for the arrangement of 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.

[0011] The invention is based on the object of providing possibilities for applying an axial preload force to a rolling bearing which are more advanced than the prior art, whereby a damping effect should also be provided.

[0012] This object is achieved according to the invention by a rolling bearing arrangement having the features of claim 1. The object is also achieved by a method for preloading a rolling bearing according to claim 8. The embodiments and advantages of the invention explained below in connection with the method according to the application also apply mutatis mutandis to the device, i.e. rolling bearing arrangement with one or more rolling bearings, and vice versa.

[0013] The rolling bearing arrangement comprises at least one rolling bearing having a bearing ring that is supported in the axial direction on a surrounding component via an elastically flexible, three-dimensionally structured thermoset element.

[0014] It has been shown that the production of the elastically supporting, three-dimensionally structured element from duroplast combines efficient manufacturing possibilities with a sufficiently high geometric precision and a long service life.

[0015] The surrounding component is, for example, a cover of a housing in which the bearing ring loaded with an axial force is inserted, whereby the bearing ring in this case is designed as an outer ring. Depending on the dimensions and overall design of the rolling bearing arrangement, a screw or an adjusting ring can be present instead of a cover, or the housing itself can form the surrounding component, for example through a housing shoulder. The invention is based on the consideration that damping elements built into a bearing arrangement represent a fundamentally suitable measure against bearing ring creep. The creep of bearing rings, i.e. movements of the bearing ring relative to a component that is essentially rigidly connected to the bearing, can be attributed in particular to micro-movements of the bearing ring and / or the component connected to the bearing ring.Such micro-movements are caused, for example, by mechanical loads that act on the bearing ring via the rolling elements during bearing operation. For background information on the topic of rolling bearing ring creep, please refer to the following publication:

[0016] 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

[0017] 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 ring and a surrounding structure was investigated both experimentally and experimentally.

[0018] Further reference is made to DE 10 2019 118 810 A1, which addresses the issue of bearing ring creep in the direction of rotation around the rotational axis of a bearing. As a countermeasure against such bearing ring creep, which could lead to premature wear, the use of form-fitting components is recommended, which prevent both rotation and axial displacement of a bearing ring.

[0019] Deviating from this known approach, the solution according to the application provides for a frictional interaction between an element, which in this case is made of a thermosetting plastic, and a bearing of a rolling bearing, for example a ball, needle or roller bearing.

[0020] According to various possible embodiments, the thermoset element of the rolling bearing assembly comprises an elastic stop ring that contacts the bearing ring over its entire surface, while the side of the stop ring facing away from the bearing ring and contacting the surrounding component is structured. The stop ring can either be present as a separate element or be integrally connected to other volume regions of the thermoset element, in particular a cylindrically shaped region that surrounds a circumferential surface of the bearing ring.

[0021] The structure of the stop ring is, for example, in the form of webs designed as spring elements. Such webs, which are integral components of the stop ring, can be aligned in particular in the radial direction of the bearing ring and thus describe an overall star shape.

[0022] The aforementioned webs, which are essentially located in a common plane perpendicular to the centerline of the rolling bearing assembly, can, optionally together with a cavity-free area of ​​the stop ring, functionally act as a replica of a disc spring. The general advantage of disc springs is that they can transmit considerable axial forces while requiring little space. This advantage is achieved in this case to a sufficient degree for the intended application, despite the fact that the spring-acting webs are made of a non-metallic material.

[0023] An additional benefit of manufacturing the thermoset element from a non-metallic material, which transmits axial forces similar to a disc spring and simultaneously provides length compensation, compared to commercially available disc springs lies in the electrically insulating properties of the thermoset material. This applies particularly to designs in which the thermoset element is at least partially formed as a casing that contacts a cylindrical circumferential surface of the bearing ring, thus functioning as an electrically insulating element overall.

[0024] The method according to the application for preloading a rolling bearing is generally characterized in that a bearing ring of the rolling bearing is provided with a three-dimensionally structured, elastically flexible thermoset element and is then loaded with an axial force via this thermoset element.

[0025] Regarding the structuring of the thermoset element during the manufacturing process, various process variants exist. Firstly, it is possible to structure the thermoset layer during the manufacturing phases associated with the application of this layer. These manufacturing phases include the coating process and the layer curing. During these phases, masking can be used, for example. It is also possible to emboss structures during curing.

[0026] Another option is to process the thermoset layer only after it has cured. This type of processing can be performed, for example, by machining with a geometrically defined or non-geometrically defined cutting edge. It is also possible to combine shaping during the coating process with subsequent machining to achieve greater geometric precision.

[0027] In all cases, the elastic, damping structure provided by the thermoset element represents not only an effective measure against bearing ring creep, but also against damage caused by standstill vibrations. The rolling bearing arrangement comprises, for example, at least one adjusted bearing, in particular in the form of an angular contact roller bearing.

[0028] Possible applications for the rolling bearing assembly include motor and generator systems, for example, in wind turbines. Mobile applications of the rolling bearing assembly are also possible, for example, in motor vehicles or rail vehicles.

[0029] An embodiment of the invention is explained in more detail below with reference to a drawing. In the drawings:

[0030] Fig. 1 shows a rolling bearing arrangement with two rolling bearings, namely ball bearings,

[0031] Fig.2 an elastic, three-dimensionally structured, axially supporting thermoset element of the arrangement according to Figure 1 together with a housing-fixed element,

[0032] Fig. 3 shows a sectional view of the arrangement according to Figure 2 together with a bearing ring of one of the two ball bearings, with at most a small axial force acting between the bearing ring and the component fixed to the housing,

[0033] Fig. 4 in a representation analogous to Figure 3 the same arrangement under higher axial load.

[0034] A rolling bearing assembly, designated overall by reference numeral 1, intended for use in a wind turbine comprises a shaft 2 supported by two rolling bearings 4, 5, namely ball bearings, in a housing 3 as the surrounding component. Each rolling bearing 4, 5 has an inner ring 6, an outer ring 9, and rolling elements 8, i.e., balls, rolling between the bearing rings 6, 9. The inner ring 6 of each rolling bearing 4, 5 is supported on a shoulder 7 of the shaft 2 running annularly around it. The rolling bearing assembly 1 is thus designed as a double-row bearing in an X-arrangement. Each outer ring 9 has a thermoset casing 10, generally referred to as a thermoset element, which covers the outer circumferential surface of the respective bearing ring 9 and, for the most part, also its end faces. In cross-section, the thermoset sheath 10 thus describes a flat U-shape, as can be seen in Figure 1.

[0035] In the embodiment shown in Figure 1, the two thermoset sheaths 10, each of which is assigned to one of the rolling bearings 4, 5, are neither identical nor mirror-imaged to each other. The thermoset sheath 10 of the rolling bearing 4 located on the left in Figure 1 has a uniform wall thickness on the cylindrical circumferential surface as well as on both end faces of the outer ring 9.In the case of the rolling bearing 5 located on the right in the arrangement according to Figure 1, the wall thickness of the left end region of the thermoset casing 10, i.e. the annular disc-shaped section of the thermoset casing 10 which faces the other rolling bearing 4, is designed with the same wall thickness as the cylindrical section of the thermoset casing 10, whereas the second end-side, outwardly facing annular disc-shaped section of the thermoset casing 10 of the rolling bearing 5 is designed as a structured stop ring 15, which will be discussed in more detail below.

[0036] Both outer rings 9 are each held in the housing 3 by a cover 11, 12. The covers 11, 12, which, like the housing 3, represent surrounding components, provide annular disk-shaped stop surfaces 13, 14, against which, in the case of the left-hand rolling bearing 4 in Figure 1, an unstructured section of the thermoset casing 10, also in the form of an annular disk, abuts, and in the case of the right-hand rolling bearing 5 in the same illustration, the aforementioned, comparatively thick, structured stop ring 15 abuts. Optionally, axial adjustability of at least one cover 11, 12 is provided, for example by means of a screw connection. In the embodiment according to Figure 1, the left-hand cover 11 represents a closed, end-face cover of the rolling bearing arrangement 1, whereas the right-hand cover 12 surrounds the shaft 2 in the shape of an annular disk.Figure 2 shows, in a schematic, partially sectioned representation, the structures of the structured stop ring 15 and the contours of the stop surface 14. The stop ring 15, which is an annular disk-shaped ring and an integral component of the thermoset casing 10, has numerous webs 14 aligned in a star shape around the central axis of the rolling bearing assembly 1, between each of which a space 17 is formed. Each of these webs 14 acts as a resilient element effective in the axial direction, with the adjacent, solid area of ​​the stop ring 15 also having a resilient effect to a lesser extent.

[0037] In the arrangement according to Figure 3, a minimal axial force F axbetween the cover 12 and the outer ring 9. The webs 16 are practically not compressed in this state. Depending on the desired design of the rolling bearing arrangement 1 and, if applicable, the variable positioning of the covers 11, 12, a play or a slight preload of the rolling bearings 4, 5 may be present in this state.

[0038] If, however, the axial force F acting on the outer ring 9 of the rolling bearing 5 axincreased, the state visualized in Figure 4 results. Here, the webs 16 are significantly compressed, while the spaces 17, which are kept free between the webs 16 and are present as grooves, are correspondingly reduced in size. The compression of the webs 16 is reversible. Thus, the thermoset casing 10, including the structured stop ring 15, exerts an axially supporting and simultaneously damping effect in every operating state of the rolling bearing assembly 1. This effect contributes significantly to reducing movements of the outer ring 9 relative to the housing 3 in the circumferential direction.

[0039] In the exemplary embodiment according to Figures 1 to 4, the structuring of the stop ring 15, visible in the form of webs 16 and gaps 17, is subsequently created by machining the thermoset casing 10. It is also possible to create the structuring during the application of the thermoset material to the outer ring 9, with the curing of the thermoset casing 10 optionally being followed by post-processing, for example, in the form of grinding. In any case, the finished, structured stop ring 15 integrated into the thermoset casing 10 acts like a disc spring, which is preloaded by the cover 12, whereby the damping effect is significantly improved compared to a disc spring.

[0040] List of reference symbols

[0041] 1 rolling bearing arrangement

[0042] Wave

[0043] 3 Housing, surrounding component

[0044] Rolling bearings

[0045] 5 rolling bearings

[0046] inner ring

[0047] 7 paragraph on the wave

[0048] 8 rolling elements, ball

[0049] 9 Outer ring

[0050] 10 Duroplast covering, Duroplast element

[0051] 11 Cover, surrounding component

[0052] 12 Cover, surrounding component

[0053] 13 Stop surface on the lid 11

[0054] 14 Stop surface on the lid 12

[0055] 15 structured stop ring

[0056] 16 jetty

[0057] 17 space

[0058] F ax axial force

Claims

Patent claims 1. Rolling bearing arrangement (1), comprising at least one rolling bearing (4, 5) which has a bearing (6, 9) which is supported in the axial direction on a surrounding component (3, 11, 12) via an elastic, three-dimensionally structured thermoset element (10).

2. Rolling bearing arrangement (1) according to claim 1, characterized in that the surrounding component (11, 12) is designed as a cover of a housing (3) in which the bearing ring (9) loaded with an axial force, namely the outer ring, is inserted.

3. Rolling bearing arrangement (1) according to claim 1 or 2, characterized in that the thermoset element (10) comprises an elastic stop ring (15) which contacts the bearing ring (6, 9) over its entire surface, whereas the side of the stop ring (15) facing away from the bearing ring (6, 9) is structured.

4. Rolling bearing arrangement (1) according to claim 3, characterized in that the structuring of the stop ring (15) is in the form of webs (16) which are designed as spring elements.

5. Rolling bearing arrangement (1) according to claim 4, characterized in that the webs (16) are aligned in the radial direction of the bearing ring (6, 9).

6. Rolling bearing arrangement (1) according to claim 4 or 5, characterized in that the webs (16) together with a region of the stop ring (15) which is free of cavities are functionally designed as a replica of a disc spring.

7. Rolling bearing arrangement (1) according to one of claims 1 to 5, characterized in that the thermosetting plastic element (10) comprises a casing which contacts a cylindrical peripheral surface of the bearing ring and is designed as an electrically insulating element.

8. Method for preloading a rolling bearing (4, 5), wherein a bearing ring (6, 9) of the rolling bearing (4, 5) is provided with a three-dimensionally structured, elastically flexible thermoset element (10) and is then loaded with an axial force via this thermoset element (10).

9. Method according to claim 8, characterized in that the structuring of the thermoset element (10), which is used to transmit an axial force on the bearing ring (6, 9), is generated during the application of the thermoset layer to the bearing ring (6, 9).

10. Method according to claim 8, characterized in that the thermoset element (10) is structured by machining only after the application and curing of the thermoset.

Images