Self-aligning roller bearing

Abstract

The invention relates to a self-aligning roller bearing (1), in particular in a wind turbine (10), comprising two bearing rings (2, 3), specifically an inner ring (2) and an outer ring (3), and barrel rollers arranged in two rows (8, 9) between the bearing rings (2, 3), each guided in a cage (19, 20), as rolling elements (7); a comb cage (19) is provided to guide the first row of rolling elements (8) and a pin cage (20) is provided to guide the second row of rolling elements (9).

Description

[0001] pendulum roller bearings

[0002] The invention relates to a double-row spherical roller bearing suitable, among other things, for use in a wind turbine according to the preamble of claim 1.

[0003] A spherical roller bearing of this type is known, for example, from DE 102019 106 276 A1. The known spherical roller bearing is intended for use as a rotor bearing in a wind turbine, assuming that an axial force is introduced into an inner ring of the bearing. According to the teaching of DE 102019 106276 A1, the axial extension of the inner ring, unlike in numerous known designs of spherical roller bearings, is greater than the axial extension of the outer ring of the same bearing. The spherical roller bearing according to DE 102019 106276 A1 can be sealed in various embodiments by contacting or non-contacting seals.

[0004] Geometric details of a double-row spherical roller bearing are disclosed in DE 102020 119948 B4. The bearing rings, including the raceways for barrel rollers as rolling elements, are each designed with mirror symmetry. A special contour of the raceways prevents the rollers from binding.

[0005] Another double-row spherical roller bearing is disclosed in DE 102017 110742 B4. In this case, the inner ring and / or outer ring is radially split to form two ring sections. The raceway of the split bearing ring has a locally deepening relief in the area of ​​the ring sections.

[0006] DE 102017 112476 A1 relates to a comb cage for an axial spherical roller bearing. The comb cage comprises a ring body and a plurality of webs projecting from the ring body, through which rolling element pockets are formed in which barrel-shaped rolling elements are guided.

[0007] The invention is based on the objective of providing a spherical roller bearing that is further developed compared to the aforementioned prior art, whereby a design suitable for stress and at the same time easy to manufacture, as well as suitability for use in a wind turbine, is sought.

[0008] This problem is solved according to the invention by a spherical roller bearing with the features of claim 1. According to claim 9, the spherical roller bearing is particularly suitable for use as a rotor main bearing in a wind turbine.

[0009] The spherical roller bearing, in a basic design known per se, comprises two bearing rings: an inner ring and an outer ring. Barrel rollers, arranged in two rows and each guided in a cage, roll between the bearing rings as rolling elements. According to claim 1, a comb cage is provided to guide the first row of rolling elements, and a pin cage to guide the second row. Thanks to the different design of the two cages, the double-row spherical roller bearing is particularly, but not exclusively, suitable for applications with asymmetrical load distribution. The general properties of spherical roller bearings, including high load-carrying capacity in both radial and axial directions, as well as the ability to accommodate limited tilting between the bearing rings, are fully present.

[0010] Regarding the bolt cage, several variations are possible. One cage variant features a number of bolts corresponding to the number of rolling elements, each bolt completely penetrating a barrel roller centrally, with the bolts connected to a side plate on both sides. An alternative cage variant consists only of bolt stubs, each engaging in blind-hole-like, centrally located recesses on the end faces of the rolling elements. In this case, the bolt cage is also referred to as a stub-bolt cage.

[0011] The stub-pin cage can have several webs connecting the cage's side plates and arranged between two rolling elements. These bolt-shaped webs are arranged, in particular, outside an imaginary cylinder defined by the central axes of the rolling elements. The number of webs, for example, corresponds to no more than one-third but more than one-sixth of the number of rolling elements.

[0012] The cage of the spherical roller bearing is typically a cast cage, for example made of an iron-based alloy. Webs are attached to a ring of the cage, each of which holds two rolling elements, i.e., barrel rollers, at a distance from each other in the circumferential direction of the bearing rings.

[0013] With various cage designs, including a stub-bolt cage, spherical roller bearings can be realized in which the number of rolling elements guided in the cage is lower than the number of rolling elements guided in the bolt cage. Specifically, the row of rolling elements guided by the bolt cage comprises exactly one more rolling element than the row of rolling elements guided by the cage. Therefore, the row of rolling elements guided by the bolt cage can withstand significantly higher forces than the row of rolling elements guided by the cage.

[0014] Regarding the shape of the rolling elements and the contact angles, which are present on the side of the rolling element row guided by the comb cage and on the side of the rolling element row guided by the pin cage, there are not necessarily differences between the rolling element rows. The spherical roller bearing can therefore be designed as a symmetrical bearing. The cages are excluded from this symmetry a priori.

[0015] According to various possible further developments, the spherical roller bearing is designed as an asymmetrical bearing. The asymmetry can relate to the shape and / or arrangement of the rolling elements. For example, one row of rolling elements may consist of longer elements and the second row of shorter elements. The central axes of the shorter rolling elements can be inclined more steeply relative to the central axis of the spherical roller bearing, thus making them more suitable for absorbing axial loads. A spherical roller bearing with two rows of rolling elements, where both the contact angles and the size of the rolling elements differ, is known, for example, from DE 10 2004047881 A1.

[0016] If the spherical roller bearing is a main rotor bearing of a wind turbine, the cage may be located on the rotor side and the pin cage on the gearbox side of the bearing. If there is also an asymmetry in the bearing arrangement, the central axes of the rolling elements on the gearbox side may have a greater skew angle relative to the central axis of the spherical roller bearing compared to the rolling elements on the rotor side. In this case, either all rolling elements may be identically shaped, or the rotor-side rolling elements, which are primarily intended to absorb radial loads, may be longer than the rolling elements of the generator-side row.

[0017] Overall, the spherical roller bearing as described in the application can be used not only in wind turbines, but also in numerous other stationary or mobile systems or machines as a load-optimized rolling bearing. Regarding the lubrication and any necessary sealing of the spherical roller bearing, solutions known from the prior art can be used. The same applies to the cage materials and the manufacturing processes. With respect to the rolling elements, case hardening is particularly feasible. If machining operations are required, for example, to create through or blind holes, these can be carried out completely or at least largely on the workpiece before it is hardened, i.e., the roller bearing currently being manufactured.

[0018] The individual components of the bolt cage, namely the side plate and the bolts (which may also be bolt stubs), can be made of the same material or of different materials. In the latter case, for example, the material from which the bolts are made is optimized for friction, and the material from which the side plates are made is optimized for mechanical strength. A friction- and / or wear-reducing coating on the cage components, especially the bolt cage, is also a possibility.

[0019] Several embodiments of the invention are explained in more detail below with reference to a drawing. This drawing shows:

[0020] Fig. 1 shows a first embodiment of a spherical roller bearing with two cages of different designs, namely a bolt cage and a comb cage, in a sectional view.

[0021] Fig. 2 shows a wind turbine including the spherical roller bearing according to Fig. 1.

[0022] Fig. 3 shows a spherical roller bearing modified compared to the embodiment shown in Fig. 1.

[0023] Fig. 4 shows a cage of the spherical roller bearing according to Fig. 3 with rolling elements inserted into the cage; Fig. 5 shows the spherical roller bearing according to Fig. 3 in a first end-face view.

[0024] Fig. 6 shows the spherical roller bearing according to Fig. 3 in a second end-face view,

[0025] Fig. 7 shows a first embodiment of an asymmetric spherical roller bearing with a collar cage and a bolt cage,

[0026] Fig. 8 shows a second embodiment of an asymmetric spherical roller bearing with a comb cage and a bolt cage.

[0027] Unless otherwise stated, the following explanations apply to all embodiments. Corresponding or essentially equivalent parts are marked with the same reference numerals in all figures.

[0028] A spherical roller bearing, designated 1, is used as the main rotor bearing in a wind turbine 10. The spherical roller bearing 1 comprises two bearing rings 2, 3, namely an inner ring 2 and an outer ring 3. A central flange of the inner ring 2 is designated 4. Furthermore, the inner ring 2 has lateral flanges 5. The outer ring contains a lubrication bore 6. In this case, the inner ring 2 is the rotating bearing of the spherical roller bearing 1, with the spherical roller bearing 1 functioning as a fixed bearing.

[0029] As shown in the overview in Fig. 2, a rotor side RS of the spherical roller bearing 1 can be distinguished from a gearbox side GS. The rotor of the wind turbine 10, located on rotor side RS, is designated 13 and comprises three rotor blades 14. The nacelle of the wind turbine 10, designated 11, is mounted on a tower 12 and includes a support structure 16, which supports, among other things, a gearbox 15 and a generator 17. The shaft 18, connected to the rotor 13 and supported by the spherical roller bearing 1, represents an input shaft of the gearbox 15.

[0030] The rolling elements, generally designated 7, i.e., barrel rollers, of the spherical roller bearing 1 are arranged in two rows of rolling elements 8 and 9. Row 8 is the rotor-side row of rolling elements 7, and row 9 is the generator-side row of rolling elements 7. A rotor-side cage, designated 19, is designed as a comb cage made of cast iron. In contrast, a cage designated 20, which guides the rolling elements 7 of the generator-side row 9, is designed as a bolt cage. In the case of the comb cage 19, a ring 21 is arranged between the two rows of rolling elements 8 and 9, to which webs 22 are formed that separate the individual rolling elements 7 of the rotor-side row 8 from one another.

[0031] The bolt cage 20 has two side plates 23 that flank the rolling elements 7 of the generator-side rolling element row 9. Various design options exist for the connections between the two side plates 23. In the embodiments shown in Figures 1, 2, and 7, the side plates 23 are connected to each other by a number of bolts 24 corresponding to the number of rolling elements 7 of the respective rolling element row 9. Each bolt 24 is inserted into a rolling element 7 through a central through-hole 25. The rolling elements 7, i.e., barrel rollers, of the generator-side rolling element row 9 can be case-hardened in all embodiments. Alternatively, induction hardening or through-hardening is possible.

[0032] In contrast to the embodiments shown in Figures 1, 2, and 7, the embodiments shown in Figures 3 to 6 and 8 have only stub bolts 26 instead of continuous bolts 24. These stub bolts extend from the side discs 23 and each engages in a blind-hole-like recess 27 on an end face of a rolling element 7. In these cases, the bolt cage 20 is thus designed as a stub bolt cage. The connection between the two side discs 23 provided by the bolts 24 in the embodiment shown in Figures 1, 2, and 7 is replaced in the embodiments shown in Figures 3 to 6 and 8 by a plurality of webs 28, which connect the two side discs 23 to each other outside the rolling elements 7. In the embodiment shown in Figures 3 and 4, a web 28 is arranged after every fifth rolling element 7 when viewed in the circumferential direction of the row of rolling elements 9. The same applies to the embodiment shown in Figure 8.Figures 5 and 6 show the spherical roller bearing 1 according to Figures 3 and 4 in end-face views. Figure 5 shows the gear side GS, and Figure 6 shows the rotor side RS. The spherical roller bearing 1 according to Figure 1 looks exactly the same in the corresponding views. Optional seals on one or both end faces of the spherical roller bearing 1 are not shown in either case.

[0033] The spherical roller bearings 1 according to Figures 7 and 8 are designed as asymmetrical bearings, unlike the embodiments shown in Figures 1 to 6. The contact angle of the first row of rolling elements 8 differs from that of the second row of rolling elements 9, with the second row 9, on the generator side, being designed to withstand axial loads more effectively. This design adapts to the force conditions that are largely present in the wind turbine 10 during operation.

[0034] In the embodiments shown in Figures 7 and 8, the rolling elements 7 of the rotor-side row 8 are guided by a cast iron cage 19. To guide the rolling elements 7 of the generator-side row 9, a bolt cage 20 with bolts 24 extending from side disk 23 to side disk 23 is used in the embodiment shown in Figure 7, as well as in the embodiment shown in Figure 1. In contrast, in the embodiment shown in Figure 8, as well as in the embodiment shown in Figures 3 to 6, a bolt cage 20 designed as a stub-bolt cage is used. In this case as well, the two side disks 23 are connected to each other by several webs 28, as sketched in Figure 4.

[0035] spherical roller bearing

[0036] inner ring

[0037] outer ring

[0038] centerboard

[0039] Board

[0040] lubrication hole

[0041] rolling elements

[0042] Rolling element array, rotor side; rolling element array, generator side; wind turbine

[0043] gondola

[0044] Tower

[0045] rotor

[0046] Rotor blade

[0047] transmission

[0048] supporting structure

[0049] generator

[0050] Wave

[0051] Cage, rotor-side, comb cage

[0052] Cage, generator side, bolt cage

[0053] Ring of the comb cage

[0054] Bridge of the comb cage

[0055] Side window of the bolt cage

[0056] bolt

[0057] through hole

[0058] bolt stub

[0059] blind-hole-like depression

[0060] Bridge of the stub bolt cage GS gearbox side RS rotor side

Claims

Patent claims 1. Spherical roller bearing (1), comprising two bearing rings (2, 3), namely an inner ring (2) and an outer ring (3), and barrel rollers as rolling elements (7) arranged between the bearing rings (2, 3) in two rows (8, 9), each guided in a cage (19, 20), characterized in that a comb cage (19) is provided for guiding the first row of rolling elements (8) and a bolt cage (20) is provided for guiding the second row of rolling elements (9).

2. Spherical roller bearing (1 ) according to claim 1 , characterized in that the bolt cage (20) has a number of bolts (24) corresponding to the number of rolling elements (7), each of which completely penetrates a barrel roller (7) centrally, wherein the bolts (24) are connected on both sides to a side disk (23).

3. Spherical roller bearing (1 ) according to claim 1 , characterized in that the bolt cage (20) as a stub bolt cage has a number of bolt stubs (26) which each engage in blind hole-like central end face recesses (27) of the rolling elements (7).

4. Spherical roller bearing (1) according to claim 3, characterized in that the bolt cage (20) has a number of webs (28) connecting two side disks (23) to each other and arranged between two rolling elements (7), wherein the number of webs (28) corresponds to no more than one third, but more than one sixth, of the number of rolling elements (7).

5. Spherical roller bearing (1) according to one of claims 1 to 4, characterized in that the comb cage (19) is designed as a cast cage.

6. Spherical roller bearing (1) according to one of claims 1 to 5, characterized in that the number of rolling elements (7) guided in the comb cage (19) is less than the number of rolling elements guided in the bolt cage (20).

7. Spherical roller bearing (1) according to one of claims 1 to 6, characterized in that it is designed as a symmetrical bearing.

8. Spherical roller bearing (1) according to one of claims 1 to 6, characterized in that it is designed as an asymmetric bearing.

9. Wind turbine, with a rotor main bearing which is designed as a spherical roller bearing (1) according to claim 1, wherein the comb cage (19) is located on the rotor side (RS) and the bolt cage (20) is located on the gearbox side (GS) of the spherical roller bearing (1).

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