Bearing assembly, in particular for wind turbines
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- FLENDER GMBH
- Filing Date
- 2024-07-12
- Publication Date
- 2026-05-20
AI Technical Summary
The existing bearing arrangement in wind turbines, particularly in medium-speed gearbox concepts, faces challenges with high position tolerances and precise preload adjustments, leading to damage from superimposed weight and electromagnetic forces, requiring complex and costly repairs that involve dismantling the entire gearbox for maintenance.
A bearing arrangement where the bearing housing and second roller bearing form a detachable cassette that can be pre-assembled and mounted separately, allowing for axial force support and preload adjustment, enabling easier maintenance without disassembling the gearbox from the tower, by integrating the axial force support into the bearing cassette and using a tapered roller bearing to absorb axial forces.
This configuration enhances accessibility and reduces maintenance costs by allowing the bearing cassette to be assembled and disassembled independently, simplifying the repair process and optimizing the use of installation space, while maintaining precise axial force management.
Smart Images
Figure EP2024069853_23012025_PF_FP_ABST
Abstract
Description
[0001] Bearing arrangement, especially for wind turbines
[0002] Description
[0003] The invention relates to a bearing arrangement for a flange region of a planetary gear for connecting a generator unit to the flange region, with a gear housing and a first rolling bearing at least indirectly accommodated therein for supporting a planet carrier of the planetary gear, a bearing housing and a shaft element rotatably mounted in the bearing housing via a second rolling bearing, wherein the bearing housing is attached to the gear housing in the axial direction.
[0004] In the wind turbine sector, there is a trend towards medium-speed gearbox concepts with a generator directly flanged to the gearbox. In this case, the output shaft element of the gearbox is designed as a hollow shaft and connected directly to the generator rotor. The bearing of the hollow shaft also serves as a bearing for the generator rotor, i.e. the rotor is at least partially mounted in the upstream gearbox. In this configuration, the bearing of the hollow shaft can also be referred to as the generator bearing. Therefore, high positioning tolerances and precise adjustment of the preload of this bearing in the gearbox must be maintained. The superposition of the weight forces and electromagnetic forces of the generator creates high stresses that can lead to damage to this bearing, requiring repair.Such an arrangement is shown, for example, in EP 3 653 907 AL. US 2007 / 0265133 A1 is also worth mentioning in this context. In the gearbox, one or more gear stages are connected upstream of the hollow shaft. Due to the required high power density, planetary gearboxes with a rotating planet carrier are generally used. The bearing of the planet carrier ensures the positioning of the gearbox elements and must, in particular, support axial forces of the upstream planetary stages or the rotor during control and reversing operation.
[0005] Typically, the generator bearing assembly consists of two tapered roller bearings mounted in the stationary generator flange and supporting or supporting the hollow shaft. In the event of damage, the flanged generator must first be completely disassembled and the generator flange heated to remove the hollow shaft and bearing. During subsequent reassembly, the bearing clearance must be readjusted, which may require several mounting and dismounting operations of the bearings on the tower.
[0006] The planet carrier can be supported by a rolling bearing on each of the rotor-side and generator-side carrier flanges. Generally, the rotor-side bearing absorbs the axial forces during reversing operation, while the generator-side bearing absorbs the axial forces during control operation. The generator-side bearing is axially supported during control operation by a support flange in the housing, forming an axial contact, so that disassembly of the bearing outer ring is only possible in the direction of the rotor. Furthermore, access is prevented by the generator bearing located behind it. This means that in the event of damage, the gearbox must be removed from the tower so that it can be opened and the corresponding stage removed. Therefore, there is a need to improve accessibility to this area, particularly during repairs.
[0007] The object of the invention is to provide measures that enable improved accessibility to the generator-side bearing of the rear planetary stage. This object is achieved by a bearing arrangement having the features of claim 1. Preferred embodiments are specified in the subclaims and the following description, each of which, individually or in combination, can represent an aspect of the invention. If a feature is presented in combination with another feature, this merely serves to simplify the presentation of the invention and is in no way intended to imply that this feature cannot also be a further development of the invention without the other feature.
[0008] One embodiment relates to a bearing arrangement for a flange region of a planetary gear unit for connecting a generator unit to the flange region, with a gear housing and a planet carrier, wherein the planet carrier is rotatably mounted about a rotation axis AD via a first rolling bearing at least indirectly received in the gear housing, a bearing housing and a shaft element, wherein the shaft element is rotatably mounted in the bearing housing via a second rolling bearing, wherein the bearing housing is attached to the gear housing in the axial direction and at least indirectly acts on an outer ring of the first rolling bearing in the axial direction against the gear housing in order to hold the rolling bearing to absorb axial forces in the axial direction.
[0009] In this case, the rotational axis AD defines the axial direction, so that the respective radial directions result from this axial direction. Depending on the underlying configuration, the shaft element can be designed as a hollow shaft. In this configuration, the shaft element can be positively connected via a spline to a sun shaft of a planetary gear stage located upstream in the torque flow. The hollow shaft element can accommodate a pitch tube through which electrical and / or hydraulic lines are routed.
[0010] The gear housing can be a housing for accommodating the planetary gear and, if applicable, the multiple planetary stages. The gear housing can be composed of multiple parts. For example, an internal gearing that functions as a ring gear for a planetary stage can be integrated into the gear housing. The gear housing can include flange areas that extend radially inward, on which the rolling bearings of the planetary stages can be supported and through which axial forces generated during operation can be introduced into the gear housing.
[0011] The bearing housing can be designed as a flange section of the entire gearbox housing, with this flange section being attached to the first gearbox element via a corresponding contact surface pair and closed on the other side with a cover element. The cover element can accommodate the passage for one or more gearbox shafts and corresponding seals.
[0012] It can be provided that a second shaft element, designed as a sun shaft and drivingly connected to the planet carrier on the one hand and to the first shaft element on the other, is provided in the transmission housing. The bearing housing with the second rolling bearing and the shaft element can be designed as a unit detachable from the transmission housing.
[0013] The first rolling bearing can be a simple tapered roller bearing, which partially and at least indirectly transmits the axial forces generated during operation of the planetary gear unit into the gear housing. The second rolling bearing can comprise several rolling bearings arranged in a composite arrangement. These bearings can be designed as spherical roller bearings, tapered roller bearings, angular contact ball bearings, or axial spherical roller bearings. An O-arrangement or an X-arrangement can be provided.
[0014] To adjust the second rolling bearing, a locknut and an annular spacer element can be provided on the shaft element. These spacers act on the inner ring of one of the two rolling bearings to generate bearing clearance and / or bearing preload. The shaft element and the spacer element each form complementarily aligned contact shoulders, and the locknut positively secures the spacer element in an axial position relative to the shaft element.
[0015] By axially attaching the bearing housing to the gearbox housing, the gearbox housing and bearing housing have a defined axial position relative to each other. The bearing housing is also at least indirectly in contact with the outer ring of the first rolling bearing, so that the outer ring is pressed against the gearbox housing and the rolling bearing is held in place to absorb axial forces in the axial direction.
[0016] The bearing housing, the second roller bearing, and the shaft element rotatably mounted in the bearing housing via the second roller bearing can be referred to as a bearing cassette, which forms a separate assembly from the gearbox housing. The bearing cassette assembly can be pre-assembled separately and mounted as a whole to the gearbox housing.
[0017] The described design allows for complete assembly and disassembly of the bearing cassette. Depending on the design, this can be done through the rear opening of the generator stator or after disassembling the generator. After disassembling the bearing cassette, the first roller bearing supporting the planet carrier can be replaced without disassembling the entire gearbox from the tower. Overall, maintenance costs and warranty claims are reduced due to improved maintainability and more effective use of the installation space by integrating the axial force support of the first roller bearing into the bearing cassette.
[0018] In a preferred embodiment, it is provided that the bearing housing has an axially directed centering shoulder which is seated in a housing opening of the gear housing.
[0019] The centering shoulder ensures that the gearbox housing and bearing housing can be positioned coaxially with each other. This is particularly helpful during maintenance, after the bearing cassette has been disassembled and can then be reassembled.
[0020] In a further preferred embodiment, the transmission housing has a radial collar against which the outer ring of the first rolling bearing is at least indirectly loaded by the bearing housing. In one possible embodiment, the radial collar can be formed on a ring element screwed to the transmission housing. The radial collar enables a defined positioning of the outer ring of the rolling bearing, so that the rolling bearing is held in the axial direction via the bearing housing to absorb axial forces.
[0021] In a particularly preferred embodiment, it is provided that the bearing housing presses the outer ring of the first rolling bearing against the gearbox housing at least via a spacer element. By adjusting the axial dimension of the spacer element, which can also be referred to as an intermediate element, it is possible to set a bearing preload, a bearing play or a jamming of the first rolling bearing as required. In particular, it is possible to have different axial dimensions of the spacer element available in the event of maintenance in order to reassemble the bearing with the correctly adjusted bearing preload during assembly after maintenance. In a specific embodiment, it can be provided that the spacer element is seated in the housing opening of the gearbox housing and that the spacer element bears against the centering projection at least over part of its circumference.Furthermore, to simplify assembly, particularly during maintenance, it can be provided that the bearing housing is held relative to the gearbox housing by a detachable connection, e.g. a screw connection.
[0022] The object is further achieved by a planetary gear unit for a rotor-driven wind turbine having at least one planetary stage rotating about a rotational axis AD in a gear element, wherein the at least one planetary stage has a planetary carrier and a bearing arrangement as described above is arranged on the output side of the planetary carrier. It is particularly preferred that the first rolling bearing comprises an adjusted tapered roller bearing arranged on one side of the planetary carrier. It is particularly advantageous that this tapered roller bearing absorbs both the axial forces during normal operation and the axial forces during reversing operation and transfers them to the gear housing.Consequently, a rotor-side bearing for the planet carrier can be dispensed with, allowing the gearbox housing to be simplified in this area, particularly in a flange area where the rotor-side rolling bearing was traditionally held. It is also conceivable that a bearing flange can be dispensed with entirely in this area. Alternatively, a separate bearing arrangement can be provided, in which the first rolling bearing arrangement comprises a pair of tapered roller bearings arranged in the axial direction on both sides of the planet carrier.
[0023] The object is further achieved by a drive train for a wind turbine for the torque-transmitting connection of a rotor to a generator, comprising a main bearing unit with a bearing housing and a main shaft and a gear driven via the main shaft, wherein the gear drives the generator at least indirectly, wherein the gear is designed as a planetary gear as described above.
[0024] Finally, the object is achieved by a wind turbine comprising a nacelle to which a multi-blade rotor and a generator are rotatably mounted, wherein the multi-blade rotor is connected to the generator in a torque-transmitting manner via a drive train and the drive train is designed as previously described.
[0025] The invention will now be explained by way of example with reference to the accompanying drawings, using preferred embodiments, wherein the features presented below can represent an aspect of the invention, both individually and in combination. They show: Fig. 1: a partial longitudinal section through a planetary gear with a conventional bearing arrangement,
[0026] Fig. 2: a partial schematic of a planetary gear with stressed bearing arrangement in a possible design,
[0027] Fig. 3: a partial schematic of a planetary gear with a stressed bearing arrangement in an alternative design,
[0028] Fig. 4: a detail of the bearing arrangement according to Fig. 2 with claimed bearing arrangement in another possible embodiment,
[0029] Fig. 5 and 6: possible variants of the mounting of the rolling bearing via a bearing sleeve and Fig. 7: a perspective view of a wind turbine.
[0030] Figure 1 shows a conventional design of a bearing arrangement 10 in a flange area 4 of a planetary gear 2, to which a generator can be connected. The generator is not shown here. The planetary gear 2 has a gear housing 12, to which the generator can be statically connected in a manner not shown. At least one planetary stage 8 is accommodated in the gear housing 12, of which only a planetary carrier 6, a rolling bearing 20 of the planet carrier 6 in the gear housing 12, and a sun shaft 34 are shown here in part. AD denotes the axis of rotation of the planetary gear. Furthermore, a shaft element 16 designed as a hollow shaft is rotatably held in the gear housing 12 via a rolling bearing 30, wherein the shaft element 16 is arranged coaxially to the sun shaft 34 and is drive-connected thereto via a short gearing 36.A cover element 38 is provided which seals the gear housing 12 and through which the shaft element 16 is passed in order to drive a rotor of the generator (not shown).
[0031] Figure 2 shows a schematic and partially sectioned view of a planetary gear unit 2 with an inventive design of the bearing arrangement 10 in a flange region 4. Figure 2 is described essentially with regard to the relevant differences from Figure 1. A gear housing 12 and a bearing housing 14 are provided. A planetary stage 8 of the planetary gear unit 2 is also accommodated in the gear housing 12. Of the planetary stage 8, only the planet carrier 6 and the sun shaft 34 are shown. Here, too, the shaft element 16 can be drivingly connected to the sun shaft 34 via a short gearing 36. A ring gear and planet gears are not shown. The planet carrier 6 is also rotatably mounted about the rotation axis AD in the gear housing 12 via a first rolling bearing arrangement 20. The first rolling bearing arrangement 20 comprises a pair of adjusted tapered roller bearings arranged on one side, namely the generator side, of the planet carrier 6.The second rolling bearing 30 is now held in the bearing housing 14, and the shaft element 16, which can be designed as a hollow shaft, is rotatably mounted in the bearing housing 14 about the rotation axis AD via the second rolling bearing 30. The bearing housing 14, the rolling bearing 30, and the shaft element 16 form part of a bearing cassette that can be attached to the transmission housing 12 and removed again if necessary.
[0032] In addition, the bearing housing 14 interacts with that of the first rolling bearing 20 in such a way that the bearing housing 14 at least indirectly loads the outer ring 22 of the first rolling bearing 20 in the axial direction against the transmission housing 12. As a result, a bearing preload of the first rolling bearing 20, which is held in the transmission housing 12, can be generated and adjusted via the bearing housing 14. The bearing housing 14 can have an axially directed centering shoulder 18, which is seated in a housing opening 24 of the transmission housing 12 and via which the bearing housing 14 bears against and loads the outer ring 22 of the first rolling bearing 20. In addition, the bearing housing 14 can at least indirectly load the outer ring 22 of the first rolling bearing 20 against a radial collar 26 of the transmission housing 12.
[0033] Figure 3 shows an alternative embodiment of the first rolling bearing 20. The first rolling bearing 20 is designed as a separate bearing which comprises adjusted tapered roller bearings arranged in the axial direction on both sides of the planet carrier 6. Figure 4 shows a possible detail of a planetary gear 2 with an inventive embodiment of the bearing arrangement 10 in a flange region 4. Figure 4 shows the first rolling bearing 20 corresponding to Figure 2, i.e. a pairing of adjusted tapered roller bearings arranged on one side of the planet carrier 6 is shown. An illustration of the also possible configuration, as shown in Figure 3, is omitted here. A spacer element 28 can be provided, via which the bearing housing 14 acts on the outer ring 22 against the gear housing 12.It is also conceivable for the spacer element 28 to be constructed in several parts and to include a separate adjustment ring (not shown here) by means of which an axial dimension can be precisely adjusted. The spacer element 28 is seated in the housing opening 24 of the gear housing 12 and forms the axial continuation of the centering shoulder 18. The bearing housing 14 is held relative to the gear housing 12 by a circumferentially arranged screw connection 32.
[0034] Figure 4 shows the first rolling bearing 20 as an adjusted tapered roller bearing in an X-arrangement. The tapered roller bearing allows the axial forces of the planetary stage 8 to be diverted into the gearbox housing 12 during both normal operation and reversing operation, specifically on the generator side of the planetary stage 8. This arrangement of the rolling bearing 20 eliminates the need for a bearing on the rotor side of the planetary stage 8, which is traditionally used to absorb the axial forces during reversing operation. Here, too, the shaft element 16 can be drive-connected to the sun shaft 34 via a short gearing 36.
[0035] Figures 5 and 6 show variants of the generator-side receptacle for the first rolling bearing 20 within the gearbox housing 20. In the variants shown, a bearing sleeve 40 is provided, via which the first rolling bearing 20, i.e. an outer ring 22 of the rolling bearing 20, is seated in the gearbox housing 12. In the variant of the bearing sleeve 40 in Figure 5, the function of the bearing sleeve 40 and the spacer element 18 - as described for Figure 40 - is combined in one component. In comparison, the bearing sleeve 40 in the variant in Figure 6 has the function of radially positioning the first rolling bearing 20 in the gearbox housing 12, while the centering shoulder 18 of the bearing housing 14 has the function of axially positioning the first rolling bearing 20 relative to the gearbox housing 12. Here, too, the shaft element 16 can be connected to the sun shaft 34 via a short gear 36. Figure 7 shows an embodiment of a wind turbine 70.The wind turbine 70 comprises a nacelle 71 to which a multi-blade rotor 72 is rotatably mounted. The multi-blade rotor 72 is connected to a main shaft 74 in a torque-transmitting manner, wherein the main shaft 74 belongs to a drive train 76. The drive train 76 further comprises a gearbox 78, which is connected to the main shaft 74 in a torque-transmitting manner. The gearbox 78 has at least one planetary stage 80 and is in turn coupled to a generator 84 via a hollow shaft assembly 82. The hollow shaft assembly 82 is received in a tapered housing section 86 of the gearbox 78. The housing section 86 can be designed as a stand-alone housing 2. A bearing arrangement 10 is provided in the hollow shaft assembly 82. The bearing arrangement 10 is designed according to one of the embodiments described above.
[0036] Reference symbol list
[0037] 2 planetary gears
[0038] 4 Flange area
[0039] 6 planet carriers
[0040] 8 planetary stage
[0041] 10 Bearing arrangement
[0042] 12 Gearbox housing
[0043] 14 bearing housings
[0044] 16 Shaft element
[0045] 18 Centering shoulder
[0046] 20 Rolling bearings
[0047] 22 Outer ring
[0048] 24 Housing opening
[0049] 26 Radial collar
[0050] 28 spacer element
[0051] 30 Rolling bearings
[0052] 32 screw connection
[0053] 34 Sunwave
[0054] 36 short toothing
[0055] 38 Lid el em ent
[0056] 40 bearing sleeve
[0057] 70 wind turbines
[0058] 71 gondola
[0059] 72 multi-blade rotor
[0060] 74 Main shaft
[0061] 76 Drivetrain
[0062] 78 gearboxes
[0063] 80 Planetary stage hollow shaft assembly generator housing section
Claims
Patent claims 1. Bearing arrangement (10) for a flange region (4) of a planetary gear unit (2) for connecting a generator unit to the flange region (4), comprising a gear housing (12) and a planet carrier (6), wherein the planet carrier (6) is rotatably mounted about a rotation axis AD via a first rolling bearing (20) at least indirectly received in the gear housing (12), a bearing housing (14) and a shaft element (16), wherein the shaft element (16) is rotatably mounted in the bearing housing (14) via a second rolling bearing (30), and the bearing housing (14) is attached to the gear housing (12) in the axial direction and at least indirectly loads an outer ring (22) of the first rolling bearing (20) in the axial direction against the gear housing (12) in order to hold the first rolling bearing (20) to absorb axial forces in the axial direction.
2. Bearing arrangement (10) according to claim 1, characterized in that a second shaft element (34) designed as a sun shaft and drivingly connected to the planet carrier (6) on the one hand and to the first shaft element (16) on the other hand is provided in the gear housing (12).
3. Bearing arrangement (10) according to claim 1 or 2, characterized in that the bearing housing (14) with the second rolling bearing (30) and the shaft element (16) forms a unit which can be detached from the gear housing (12).
4. Bearing arrangement (10) according to one of claims 1 to 3, characterized in that the bearing housing (14) has an axially directed centering shoulder (18) which is seated in a housing opening (24) of the gear housing (12).
5. Bearing arrangement (10) according to one of claims 1 to 4, characterized in that an outer ring (22) of the first rolling bearing (20) is seated in the gear housing (12) via a bearing sleeve (40).
6. Bearing arrangement (10) according to one of claims 1 to 5, characterized in that the bearing housing (14) acts on an outer ring (22) of the first rolling bearing (20) at least via a spacer element (28).
7. Bearing arrangement (10) according to claim 5 and 6, characterized in that the bearing sleeve (40) and the spacer element (28) are functionally combined in one component.
8. Bearing arrangement (10) according to claim 4 and 7, characterized in that the spacer element (28) is seated in the housing opening (24) of the gear housing (12) and the spacer element (28) bears against the centering projection (18) at least partially.
9. Bearing arrangement (10) according to one of claims 1 to 8, characterized in that the bearing housing (14) is held detachably relative to the bearing housing (12), in particular via a circumferentially arranged screw connection (32).
10. Planetary gear (2) for a wind turbine (100) driven by a rotor (106) with at least one planetary stage (8) rotating about an axis of rotation AD in a gear housing (12), wherein the at least one planetary stage (8) has a planetary carrier (6) and on the output side of the planetary carrier has a bearing arrangement (10) according to one of the preceding claims.
11. Planetary gear according to claim 10, characterized in that the first rolling bearing (20) comprises an adjusted tapered roller bearing arranged on one side of the planet carrier (6).
12. Planetary gear according to claim 10, characterized in that the first rolling bearing (20) comprises tapered roller bearings arranged in the axial direction on both sides of the planet carrier (6).
13. Drive train (102) for a wind turbine (100) for the torque-transmitting connection of a rotor (106) to a generator (112), comprising a main bearing unit (108) with a bearing housing (120) and a main shaft (118) and a gear (10) driven via the main shaft (118), wherein the gear (10) drives the generator (112) at least indirectly, characterized in that the gear (10) is designed as a planetary gear according to claim 10, 11 or 12.
14. Wind turbine (70) comprising a nacelle (71) to which a multi-blade rotor (72) and a generator (84) are rotatably mounted, wherein the multi-blade rotor (72) is connected to the generator (84) via a drive train (76) in a torque-transmitting manner, and the drive train (76) is designed according to claim 13.