Transmission drive train with tilt compensation

Abstract

The invention relates to a transmission drive train (10) having a drive train axis AD for a wind turbine (100), having a transmission housing (12), a first and at least one further planetary stage and / or spur gear stage (20), (22) rotatable about the drive train axis AD, wherein a ring gear (14) of the first planetary stage (12) is designed as a housing component of the transmission housing (12), and the first planetary stage (20) has a planetary carrier (16) with planetary gears (18) accommodated therein, wherein the planetary gear carrier (16) is rotatably mounted with respect to the transmission housing (12) on a first axial side by means of a first bearing (26) and on a second axial side by means of a second bearing (32). A bearing seat (28) of the first bearing (26) and a bearing seat (34) of the second bearing (32) have a radial offset Vr with respect to one another. In a loaded state, the tilting between the teeth is eliminated.

Description

[0001] FLENDER GMBH Düsseldorf, October 17, 2025

[0002] Our reference number: FD45748 - 2024P04722WO

[0003] Flender GmbH

[0004] Alfred-Flender-Str. 77, 46395 Bocholt, Germany

[0005] Gear drive train with tilt compensation

[0006] Description

[0007] The invention relates to a gear drive train with a drive train axis AD for a wind turbine, comprising a gearbox housing, a first and at least one further planetary stage and / or spur gear stage rotatable about the drive train axis, wherein a ring gear of the first planetary stage is designed as a housing component of the gearbox housing and the first planetary stage has a planet carrier with planet gears received therein, wherein the planet gear carrier is rotatably mounted relative to the gearbox housing on a first axial side with a first bearing and on a second axial side with a second bearing.

[0008] Wind turbines can utilize so-called four-point bearings – also known as dispersed bearings – with a double-bearing rotor shaft to absorb bending moments and an attached gearbox / generator unit with a torque arm. In this configuration, the weight of the gearbox / generator unit is not supported by the surrounding structure – usually the machine support for attaching it to the tower – but rather by the rotor shaft and its bearings in the bearing housing. The weight of the rotor and the rotor hub acts as a counterweight to the weight of the gearbox / generator unit. However, wind turbines can also employ so-called two-point bearings with a coupling between the rotor shaft and the gearbox input. In this configuration, the gearbox input is typically formed by a planetary gear carrier.The weight of the gearbox housing and bearing compliance cause deformation in the bearings, which can lead to unfavorable tilting of the gear teeth. This effect is particularly pronounced with single-sided bearing support or significant deflection due to the gearbox housing's high weight or high bearing compliance. The tilting of the gear teeth results in uneven and unfavorable loading and must be considered during the design process, leading to heavier designs or gearboxes with lower torque carrying capacity. There is a constant need to minimize, and ideally eliminate, this tilting of the gear teeth.

[0009] The purpose of the invention is to demonstrate measures that at least minimize the tilting in the gearing.

[0010] The problem is solved by a transmission drive train with the features of claim 1. Preferred embodiments are specified in the dependent claims and the following description, each of which, individually or in combination, can represent an aspect of the invention.

[0011] One embodiment relates to a gear drive train with a drive shaft for a wind turbine for torque transmission in one direction M, comprising a gear housing, at least one first planetary stage rotatable about the drive shaft axis, or at least one first planetary stage and a subsequent gear stage, wherein a ring gear of the at least first planetary stage is designed as a housing component of the gear housing, and the first planetary stage has a planet carrier with a first central shaft containing planet gears, wherein the planet carrier is rotatably mounted relative to the gear housing by means of a first and second bearing viewed in the direction M, wherein a bore axis ABI of a housing-side bearing seat of the first bearing and a bore axis AB2 of a housing-side bearing seat of the second bearing exhibit a radial offset V in the direction of the weight force acting on the gear drive train. rto each other

[0012] For the following analysis, a distinction must be made between an unloaded and a loaded state. A state in which the force of gravity does not act on the transmission drivetrain or on any of its components can also be described as an unloaded or unloaded state. In such a state, the transmission drivetrain is not subjected to its own weight, so there are no deformations due to material compliance. Any play between moving parts is not exploited in one direction but remains within its clearance or tolerance range. This state, in which the force of gravity is not effective, can initially be described as a virtual state, for which the design is planned in a corresponding calculation program during the design phase.From a purely practical standpoint, this state, in which the system's own weight is not acting, can also be achieved during the assembly of a wind turbine using such a gearbox drive train. Specifically, this can occur when the gearbox drive train and its components are still suspended from an assembly crane but have already been attached to the rest of the wind turbine structure. It is also conceivable that this unloaded state is achieved when the gearbox components and adjacent parts, such as a main bearing housing, are connected on a flat surface, so that the weight is supported by the surface itself and not by the connecting elements between the components.

[0013] In addition to the drivetrain axis AD, a first central axis AMI can be defined for the first planetary stage, and a second central axis AM2 for the gearbox housing, including any further planetary stages. For the described unloaded state, it can be specifically provided that the second central axis AM2 is inclined vertically upwards from an intersection point with the first central axis AMI in the direction of at least the second planetary stage. In the described unloaded state, the central axis AM2 of the gearbox housing is arranged at an angle UVK to the drivetrain axis AD, so that a tilting occurs between the gear teeth. This tilting in the unloaded state is, however, negligible, since the gearbox drivetrain is not in operation.When the unloaded state is released, the tilting moment resulting from the weight of the gearbox housing and the other planetary stages takes effect, causing the gearbox housing to compress and reducing or even eliminating the tilting in the gearing.

[0014] The proposed gear drive train avoids or at least significantly reduces the negative effect of gear tilt, particularly in the first planetary stage, resulting in a considerably improved load-bearing capacity of the gear teeth. Uneven loading in the two bearings of the first planetary stage's carrier and within the first planetary stage's gearing—especially between the ring gear and the planet gears—is prevented. The initial or design-integrated offset of the housing-side bearing seats ensures that the planetary shafts exhibit no angular misalignment with the ring gear during operation, thus guaranteeing uniform bearing loads and uniform loading within the first planetary stage's gearing.

[0015] In a preferred embodiment of the transmission drive train, the radial offset is +V rThe bearing seat of the first bearing, relative to the drivetrain axis AD, is oriented in the opposite direction to the weight force FRG acting on the transmission drivetrain. Consequently, the bearing seat is shifted vertically upwards compared to its initial state.

[0016] In a further preferred embodiment of the transmission drive train, the radial offset -V rThe bearing seat of the second bearing, relative to the drivetrain axis, is oriented in the direction of the weight force acting on the transmission drivetrain. Consequently, the bearing seat is shifted vertically downwards compared to the initial state. Thus, it can be provided that the first bearing, which is the rotor-side bearing, and the second bearing, which is the generator-side bearing, are shifted in opposite directions. In a specific embodiment, it can be provided that the first and the second bearings are each designed as rolling bearings. In one possible embodiment with regard to the bearing arrangement, it can be provided that the first and second bearings are arranged on opposite sides of the planet carrier 16 when viewed in the torque direction M.In an alternative embodiment with regard to the bearing arrangement, it can be provided that the first and the second bearing are designed as double tapered roller bearings n on the input side of the planet carrier 16, viewed in the direction of torque M.

[0017] In a further preferred embodiment, it may be provided that a central axis AL of a raceway of the housing-side bearing ring of the first and / or the second bearing is set at an angle to the drive train axis AD.

[0018] In a further preferred embodiment of the transmission drive train, it is provided that an outer bearing ring of the first bearing is held in the housing-side bearing seat and an inner bearing ring or an outer bearing ring of the second bearing is held in the housing-side bearing seat.

[0019] In a further embodiment of the gear drive train, it can be provided that an electric machine connected to the gear housing is subordinate to at least one planetary stage.

[0020] The task is further solved by a wind turbine with a rotor flange with a rotor and a generator, wherein a geared drive train connecting the rotor flange to the generator is provided and the geared drive train is designed as described.

[0021] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments. The drawings show: Fig. 1: a schematic representation of a drive train of a wind turbine; Fig. 2: a schematic and partial representation of a geared drive train.

[0022] Fig. 3: a detailed view of the gearbox drive train according to Fig. 2 with radially offset planetary carrier bearing,

[0023] Fig. 4, 5: an embodiment of a gear drive train for compensating for an angular tilting and

[0024] Fig. 6: a detailed view of the first bearing of the first planetary carrier.

[0025] Figure 1 shows a schematic, not-to-scale representation of a wind turbine 100 in one possible embodiment. A side view is shown. The essential element of the wind turbine 100 is a drive train 102, which in this case can structurally comprise a rotor flange 104 with a rotor 106, a rotor bearing 108, a gearbox component 12, and a generator 112. At least the rotor bearing 108 and the generator 112 are supported on a ground via a machine carrier 114 and a tower (not shown). The rotor bearing 108 comprises a rotor shaft 118, which is rotatably mounted about a drive train axis AD relative to a rotor bearing housing 120 of the rotor bearing 108, for example, by means of an angled tapered roller bearing. The drive train axis AD defines an axial direction. M denotes a torque direction in a standard operating condition.

[0026] The rotor flange 104 is mounted at one end of the rotor shaft 118, and the rotor 106 is mounted to the flange. A gear unit 12 is connected to the other end of the rotor shaft 118 to transmit a drive torque applied by the rotor 106. The gear unit 12 is designed as a planetary gear unit with one or more planetary stages. The gear unit 12 is connected to the generator 112. The rotor bearing housing 120 is connected to the gear unit 12 via a flange 126. A reaction torque of the gear unit 12 – and also of the flanged generator 112 – is supported against the machine carrier 114 by a torque arm 116. In a first embodiment, the torque arm 116 – as shown in Figure 1 – can connect the gear unit 12 directly to the machine carrier 114.The machine carrier 114, the rotor bearing 108 with rotor shaft 118, the torque support 116 and the gearbox component 12 can be referred to as drive train bearing 10.

[0027] Figure 2 schematically and partially shows a geared drive train 10 for a wind turbine 100, driven about the drive train axis AD, as shown, for example, in Figure 1. A gearbox housing 12 is provided, in which, in this case, a first, a second, and a third planetary stage 20, 22, and 40 are accommodated. A generator 112 can also be flanged to the gearbox housing 12. The second and third planetary stages 22 and 40 are shown here only by their reference numerals as placeholders. A ring gear 14 of the first planetary stage 12 is designed as a housing component of the gearbox housing 12. The first planetary stage 20 has a planet carrier 16 with planet gears 18 accommodated therein. A sun gear of the planetary stage 20 is not shown here.The planet carrier 16 is rotatably mounted relative to the gearbox housing 12 on a first axial side by a first bearing 26i and on a second axial side by a second bearing 262. The gearbox housing 12 has corresponding bearing seats 28 and 34 on its housing side for this purpose. The designations "first" and "second axial side" initially refer to the drive train axis AD. Furthermore, for the purposes of this analysis, it is defined that the first axial side is the side facing the rotor 106 – see Figure 1 – and the second axial side is the side facing the generator 112. From this, the axial direction M shown in Figure 1 extends from the first axial side to the second axial side.

[0028] The ring gear 14 of the first planetary stage 20, the second and third planetary stages 22, 40, and the optional generator 112 are hereinafter also designated with the reference numeral 24 and referred to as the core gearbox. The gearbox housing 12 is considered part of the core gearbox 24. For the planet carrier 16 of the first planetary stage 20 and the core gearbox 24, respective component-specific center axes AMI and AM2 can be defined. Due to the tilting moment MK resulting from the weight force FRG of the core gearbox 24 and due to bearing clearance and compliance of the bearings 26i, 262, the core gearbox 24 experiences an angular tilting. This angular tilting is shown in Figure 2 and can be described as a loaded state, in contrast to an unloaded state in which no weight force FRG is effective and which is described with reference to Figure 4.The central axis AM2 of the gearbox 24 is therefore tilted downwards by an angle -UVK relative to the central axis AMI of the first planet carrier 16. The tilted central axis AM2 of the gearbox 24 is designated -UVK, where the magnitude of the angle UVK describes the position of the central axis AM2 of the gearbox 24 relative to the central axis AMI of the first planet carrier 16. The negative sign of the angle avK describes the orientation of the central axis AM2 relative to the central axis AMI; namely, starting from an intersection point between the central axis AMI and the central axis AM2, the central axis AM2 is inclined vertically downwards in the direction of the gearbox 24.

[0029] The angular tilting -avK leads to a tilting of the gear teeth in the planetary stage 20, in particular between ring gear 14 and planet carrier 16. For the consideration of the angular tilting due to the weight force FRG of the core gearbox 24 and the resulting tilting moment MK, a fixed or unchanged position of the planet carrier 14 is assumed.

[0030] Figures 3, 4, and 5 show an embodiment of a geared drive train 10 for compensating the angular tilting caused by the weight force FRG of the gearbox 24. In Figure 3, ABI denotes the bore axis of the housing-side bearing seat 28 of the first bearing 26i, and AB2 denotes the bore axis of the housing-side bearing seat 34 of the second bearing 262. Initially, or in a starting state, the respective bore axes ABI and AB2 of the bearing seats 28 and 34 coincide with the drive train axis AD, i.e., they are coaxial. Figure 3 shows a vertical displacement of the housing-side bearing seats 28 and 34 and the respective bore axes ABI and AB2, relative to the drive train axis AD. The vertical direction here corresponds to the direction of a weight force FRG acting on the geared drive train 10.In this context, embodiments can be provided in which either the bearing seat 28 is offset with the bore axis ABI, or the bearing seat 34 with the bore axis AB2, or both bearing seats 28 and 34 are offset with their respective bore axes ABI and AB2. In each of these cases, both bore axes ABI and AB2 have a radial offset V. r They are offset from each other. The offset can also be described as a displacement.

[0031] If the bearing seat 28 or the bore axis ABI of the bearing 26i is shifted vertically upwards, the shift is increased with +V rThe displacement is denoted by -Vr. If the bearing seat 34 or the bore axis AB2 of the bearing 262 is shifted vertically downwards, the displacement is denoted by -Vr. Figure 3 shows both the conventional bearing position and the modified bearing position after displacement of both housing-side bearing seats 28, 34 or the bore axes AB1, AB2. Figure 3 also shows the gearbox housing 12 and the planet carrier 16 in a coaxial position with respect to the drivetrain axis AD. In Figure 3, the gearbox housing 12 and planet carrier 16 have not yet been tilted due to an effective weight force FRG or the displacement of the bearing seats 28, 34.

[0032] Figure 4 shows the unloaded state, in which the gearbox housing 24 is not subjected to its own weight FRG, so that there are no deformations due to material compliance. Figure 4 also shows the displaced housing-side bearing seats 28, 34, as described in detail in Figure 3. The planet carrier 16 has an unchanged position in Figures 3 and 4, so that in Figure 4 the gearbox housing 12 has been pivoted vertically upwards to accommodate the changed position of the bearing seats 28, 34. The central axis AM2 of the gearbox housing 24 is therefore inclined upwards by an angle +avK relative to the central axis AMI of the first planet carrier 16. Reference numeral 38 denotes the planes on the resonant side of the ring gear 14. Reference numeral 42 denotes the planes on the end faces of the planet gears 18.It can be seen that the angle +avK is also established between the planes 38 of the ring gear 14 on the one hand and the planes 42 of the planet gears 18 on the other. Figure 5 shows the loaded state in which the gearbox 24 experiences an angular downward tilting due to the tilting moment MK resulting from the weight force FRG. As a result of the displacement of the housing-side bearing seats 28 and 34 relative to the central axis AMI, as described in Figure 4, the central axis AM2 of the gearbox 24 is now coaxial with the central axis AMI of the first planet carrier 16. This coaxial alignment of the two central axes AMI and AM2 with respect to each other ensures that there is no tilting of the gear teeth in the planetary stage 22, in particular between the ring gear 30 and the planet carrier 14, so that no angle other than zero degrees is established between the planes 38 of the ring gear 14 on the one hand and the planes 42 of the planet gears 18 on the other.

[0033] Figure 6 shows a detailed view of the first bearing 26i. It can be seen that a central axis AL of a raceway AL of the housing-side bearing ring 30 of the first bearing 26i is angled relative to the drive train axis AD.

[0034] Reference symbol list

[0035] 10 Transmission drivetrain

[0036] 12 Gearbox housings

[0037] 14 Ring gear

[0038] 16 planetary carriers

[0039] 18 planetary gears

[0040] 20th planetary stage

[0041] 22nd planetary stage

[0042] 24 trunk gearboxes

[0043] 26 warehouses

[0044] 28 bearing seat

[0045] 30 Outer bearing ring

[0046] 32 Storage

[0047] 34 bearing seat

[0048] 36 inner bearing ring

[0049] 38 voting levels

[0050] 40th planetary stage

[0051] 42 voting levels

[0052] 44th stage of the twang wheel

[0053] 46 Outer bearing ring

[0054] 48 career

[0055] 100 wind turbines

[0056] 102 Drive string

[0057] 104 Rotor flange

[0058] 106 multi-blade rotor

[0059] 108 Rotor bearing

[0060] 112 Generator

[0061] 114 machine carriers

[0062] 116 Torque support rotor shaft rotor bearing housing generator shaft flange

Claims

P a t e n t a n s p r ü c h e 1. Gear drive train (10) with a drive train axle (AD) for a wind turbine (100) for torque transmission in an axial direction (M), comprising a gearbox housing (12), at least one first planetary stage (12) rotatable about the drive train axle (AD), or at least one first planetary stage (12) and a subsequent spur gear stage (40), wherein a ring gear (14) of the at least first planetary stage (12) is designed as a housing component of the gearbox housing (12), and the first planetary stage (20) has a planet carrier (16) with a first central axle (AMi) with planet gears (18) received therein, wherein the planet carrier (16) is rotatably mounted relative to the gearbox housing (12) by means of a first and second bearing (26i, 262) viewed in the axial direction (M), characterized in thatthat a bore axis (ABI) of a housing-side bearing seat (28) of the first bearing (26i) and a bore axis (AB?) of a housing-side bearing seat (34) of the second bearing (262) in the direction of the weight force (FRG) acting on the transmission drive train (10) have a radial offset (V, r ) to each other.

2. Gear drive train (10) according to claim 1, characterized in that the radial offset (+V r ) the bore axis (ABI) of the bearing seat (28) of the first bearing (26i) is directed opposite to the direction of the weight force (FRG) acting on the transmission drive train (10) with respect to the drive train axis (AD).

3. Gear drive train (10) according to claim 1 or 2, characterized in that the radial offset (-V r) the bore axis (AB2) of the bearing seat (34) of the second bearing (26i) is directed in the direction of the weight force (FRG) acting on the transmission drive train (10) with respect to the drive train axis (AD).

4. Gear drive train (10) according to one of claims 1 to 3, characterized in that the first and the second bearing (26i, 262) are each designed as rolling bearings.

5. Gear drive train (10) according to one of claims 1 to 4, characterized in that the first and the second bearing (26i, 262) are designed as double tapered roller bearings in an O-arrangement viewed in the direction (M) on the input side of the planet carrier (16).

6. Gear drive train (10) according to one of claims 1 to 4, characterized in that the first and the second bearing (26i, 262) are arranged on opposite sides of the planet carrier (16) when viewed in the direction (M).

7. Gear drive train (10) according to one of claims 1 to 6, characterized in that a bearing outer ring (30) of the first bearing (26i) is held in the housing-side bearing seat (28) and a bearing inner ring (36) or a bearing outer ring (46) of the second bearing (262) is held in the housing-side bearing seat (34).

8. Gear drive train (10) according to one of claims 1 to 7, characterized in that a central axis (AL) of a raceway (48) of the housing-side bearing ring (30) of the first and / or the second bearing (26i, 262) is angled relative to the drive train axis (AD).

9. Gear drive train (10) according to one of claims 1 to 8, characterized in that an electric machine (112) connected to the gear housing (12) is arranged downstream of the at least one planetary stage (20).

10. Wind turbine (100) comprising a rotor flange (104) with a rotor (106) and a generator (112), wherein the rotor flange (104) is connected to the generator (112) connecting transmission drive train (10) is provided, characterized in that the transmission drive train (10) is designed according to one of the preceding claims.

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