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, comprising a first and at least one further transmission component (12), (20) each having a central axis AM1, AM2, wherein the first transmission component (12) has at least one planet carrier (14) with planets of a first planetary stage (22) received therein, a first housing element (28) as a flange section with a received bearing (16) for the planet carrier (14), and a second housing element (30) as a ring gear, and the second transmission component (20) has at least one further planet stage and / or spur gear stage (26). In a state in which a weight FRG of the at least one further transmission component (20) does not act on said transmission component (20), the central axis AM2 of the at least one further transmission component (20) is at an angle +αVK with respect to the drive train axis AD. In a loaded state, the tilting between the toothing is eliminated.

Description

[0001] FLENDER GMBH Düsseldorf, August 26, 2025

[0002] Our reference number: FD 45703 - 2024P04721WO

[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 axle AD for a wind turbine, with a first and at least one further gear component, each with a central axle AMI, AM2, wherein the first gear component has at least one planet carrier with planets of a first planet stage received therein, a first housing element as a flange section with a bearing received for the planet carrier and a second housing element as a ring gear, and the second gear component has at least one further planet and / or gear stage.

[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. US Patent 2007 / 142156 A1 shows a planetary gearbox for a wind turbine and describes a non-coaxial arrangement of the bearing center axes relative to the axes of rotation of the planet gears. However, wind turbines can also utilize so-called two-point bearings with a flexible coupling between the rotor shaft and the gearbox input.The gearbox input is typically formed by a planet carrier. This planet carrier is not fully supported by the rotor shaft but rests against the surrounding structure via a carrier bearing. Its own weight and bearing compliance cause deformation in the bearing, which can lead to unfavorable tilting of the gear teeth. This effect is particularly pronounced with a single-sided bearing or significant deflection due to high planet carrier weight or high bearing compliance. The tilting of the gear teeth results in uneven and unfavorable loading and must be considered in the design, 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.

[0011] One embodiment relates to a geared drive train with a drive train axis AD for a wind turbine, comprising a first and at least one further gear component, each with a central axis AMI, AM2, wherein the first gear component has at least one planet carrier with planets of a first planetary stage received therein, a first housing element as a flange section with a bearing received for the planet carrier and a second housing element as a ring gear, and the second gear component has at least one further planet and / or ring gear stage, wherein in a state in which a weight force of the at least one further gear component is not acting on this gear component, the central axis AM2 of the at least one further gear component is at an angle UVK to the drive train axis AD.

[0012] A state in which the force of gravity does not act on the transmission component can also be described as a relieved or unloaded state. In such a state, the transmission component is not subjected to its own weight, so there are no deformations due to material compliance. Any play between moving parts is not exploited to one side, but remains centered 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 the described unloaded state, the second central axis AM2 can be specifically designed so that, starting from an intersection point with the first central axis AMI, it is inclined vertically upwards in the direction of the at least second gear component. In the described unloaded state, the central axis AM2 of the at least one further gear component is arranged at an angle avK to the drivetrain axis AD, so that a tilting occurs between the gear teeth. This tilting in the unloaded state is negligible, however, since the gear drivetrain is not in operation. If the unloaded state is now released, the tilting moment resulting from the weight of the at least one further gear component acts, causing the at least one further gear component to compress, and the tilting in the gear teeth is reduced or even eliminated.

[0014] The proposed gear drive train avoids or at least reduces the negative effect of gear tilt, particularly in the first planetary stage, to such an extent that significantly improved gear-bearing behavior is achieved. Advantageously, by aligning the central axis of the first planetary stage at an angle to the central axis of the second or subsequent planetary stages, including their housing components, with respect to a weight-free state of these second or subsequent planetary stages, tilting in the slow planetary stage between the ring gear (or its internal teeth) and the planet carrier (engagement of the planet gears with the internal teeth) and between the sun gear and the planet carrier (engagement of the planet gears with the sun gear) is avoided.The proposed gearbox drive train takes into account the ever-increasing power output of wind turbines and the associated rise in weight of the gearbox and generator, as well as the increased dimensions and thus the leverage for the tilting moment caused by the weight. The resulting tilting moment therefore no longer needs to be compensated for by oversizing the affected machine elements – rotor shaft, rotor bearings, planet carrier, planet carrier bearings, and gearbox-rotor flange. Furthermore, a counterweight support between the gearbox-generator unit and the machine frame, which would be detrimental with regard to potential load overloads, can be omitted.

[0015] In possible preferred embodiments of the gear drive train, the flange section arranged around the central axis AMI has a contact surface, wherein the contact surface is at an angle of 90°+(avK), (-OIVK), or (+UVK) to the drive train axis AD. In these configurations, the flange section ensures that, in the unloaded state, the two central axes AMI and AM2 are perpendicular to each other. The first configuration is preferably achieved by attaching the flange section to the ring gear via the contact surface, which is at an angle of 90°+avK to the drive train axis AD. Advantageously, the ring gear remains structurally and functionally unchanged.With regard to a complete drive train of a wind turbine, the first housing element, designed as a flange section, can serve as a torque support and can be arranged either on the rotor side of the first planetary stage or on the side of the first planetary stage facing away from the rotor.

[0016] The two other possibilities are realized by the fact that the flange section, whose contact surface is at the angle -avK or at the angle +avK to the drive train axis AD, is a bore for receiving the bearing for the planetary gear carrier.

[0017] A preferred embodiment of the bearing arrangement for both of the aforementioned possibilities provides that the planetary gear carrier is supported via a one-sided guide bearing in the first housing element designed as a flange section or on the side facing away from the first housing element in the housing element.

[0018] In an alternative preferred embodiment, a central axis AM3 of the ring gear has a first radial offset V ricompared to the flange section arranged around the central axis AMI. Here, the conventional coaxial alignment and mounting of the components' axes of symmetry is deliberately deviated from in order to advantageously arrange the two central axes AMI and AM2 at an angle to each other in the unloaded state. In a simple case, it may suffice to mount the ring gear relative to the flange section only within the existing hole pattern with the radial offset Vn. However, it can also be provided that the hole pattern of the ring gear, or additionally the hole pattern of the flange section, is manufactured with the intended offset Vri and then mounted accordingly with the offset hole pattern. In a further preferred embodiment, it can be provided that the central axis AM2 of the second gear component has a second radial offset V. r2 compared to the flange section arranged around the central axis AMI. In particular, it can be provided that the first radial offset V ri is directed opposite to the second radial offset Vr2. In the described alternative preferred embodiment, it can be provided that the planetary gear carrier of the first transmission component is supported relative to the second transmission component by a further bearing.

[0019] In summary, regarding the described configurations, it can be stated that in an unloaded or unloaded state, 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 gear component. During operation or after final assembly, a tilting moment induced by the weight force results in a tilt of -avK in the cases described above, thus compensating for the initial tilt in the unloaded state.

[0020] The magnitude of the angular deviation from avK is determined based on the planetary carrier bearing clearance, the distance between the planetary carrier bearings, the compliance of the planetary carrier bearings, the compliance of the support structure for the planetary carrier bearings, and the magnitude of the expected tilting moment. This value can be accurately determined in advance, as these are design parameters that are known or can be determined during the design process. Ideally, the design and adjustment are chosen to completely compensate for the tilting.

[0021] The problem is further solved by a wind turbine comprising a rotor flange with a rotor and a generator, wherein a geared drive train connecting the rotor flange to the generator is provided, characterized in that the geared drive train is designed as described. The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments. The drawings show:

[0022] Fig. 1: a schematic representation of a wind turbine,

[0023] Fig. 2: schematic and partial representation of a gear drive train,

[0024] Figs. 3 to 5: a first embodiment of a gear drive train for compensating for angular tilting,

[0025] Fig. 6: another embodiment of a flange section for compensating for angular tilting and

[0026] Fig. 7, 8: another embodiment of a gear drive train 10 for compensating for angular tilting.

[0027] Figure 1 shows a schematic representation, not to scale, of a possible embodiment of a wind turbine 100. 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.

[0028] At one end of the rotor shaft 118, the rotor flange 104 is mounted, and the rotor 106 is mounted to the flange. The other end of the rotor shaft 118 is connected to a drive component 12 to transmit a drive torque applied by the rotor 106. The drive component 12 is designed as a planetary gear unit with one or more planetary stages. The drive component 12 is connected to the generator 112. The rotor shaft bearing 108 is connected to the drive component 12 via a flange 126. A reaction torque of the drive component 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 drive component 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.

[0029] Figure 2 schematically and partially shows a gear drive train 10 for a wind turbine 100, as shown, for example, in Figure 1, with a first gear component 12 and a second gear component 20. The first gear component 12 comprises a first planetary stage 22 with a planet carrier 14, a first housing element 28 designed as a flange section, a second housing element 30 designed as a ring gear, and a bearing arrangement 16. The planet carrier 14 is rotatably mounted about an axis of rotation AD relative to the flange section 28 via the bearing arrangement 16. The flange section 28 is indirectly held on a further housing element 32 of the second gear component 20 via the ring gear 30. The second gear component 20 has at least one further planetary stage 26, but can also alternatively or additionally include a spur gear stage.The second transmission component 20 is hereinafter also referred to as the core transmission, designated by reference numeral 24. Separate central axes AMI and AM2 can be defined for the first transmission component 12 and the core transmission 24.

[0030] Due to the tilting moment MK resulting from the weight FRG of the gearbox 24, and as a result of bearing play and compliance of the bearing arrangement 16, the gearbox 24 experiences an angular tilting. This angular tilting is illustrated in Figure 2. Consequently, the central axis AM2 of the gearbox 24 is tilted downwards by an angle -avK relative to the central axis AMI of the first gearbox component 12. The tilted central axis AM2 of the gearbox 24 is designated -avK, where the magnitude of the angle avK describes the position of the central axis AM2 of the gearbox 24 relative to the central axis AMI of the first gearbox component 12. 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.

[0031] The tilting moment is denoted by MK. The angular tilting -avK leads to a tilting of the gear teeth in the planetary stage 22, in particular between the ring gear 30 and the planet carrier 14. For the analysis of the angular tilting due to the weight force FRG of the gearbox 24 and the resulting tilting moment MK, a fixed or unchanged position of the planet carrier 14 is assumed.

[0032] Figures 3, 4, and 5 show a first embodiment of a gear drive train 10 for compensating the angular tilting caused by the weight FRG of the gearbox 24. Figure 3 shows the unloaded state, in which the gearbox 24 is not subjected to its own weight, so that there are no deformations due to material compliance. The central axis AM2 of the gearbox 24 is therefore inclined upwards by an angle +avK relative to the central axis AMI of the first gear component 12. Figure 4 shows a flange section 28 configured such that the central axis AM2 of the gearbox 24 is positioned upwards by the angle +avK. The flange section 28 has a contact surface 34 that is at an angle of 90° + (avK) to the central axis AMI.Since the core gearbox 24 is indirectly connected to the flange section 28 via the ring gear 30 and the contact surface 34, the central axis AM2 of the core gearbox 24 is at an angle +avK with respect to the central axis AMI. Alternatively, the contact surface 34 can also be provided on the end face of the ring gear facing the flange section 28, in which case the contact surface 34 is at an angle of 90° on the ring gear. 0-(OIVK) with respect to the central axis AMI. 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 design of the flange section 28 shown in Figure 4, the central axis AM2 of the gearbox 24 is now coaxial with the central axis AMI of the first gearbox component 12 and coaxial with the drivetrain axis AD. This coaxial orientation of the two central axes AMI and AM2 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.

[0033] Figure 6 shows another possible embodiment of the flange section 28. Here, the contact surface 34 is designed as a bore for receiving the bearing 16 for the planet carrier 14, the bore being arranged not coaxially, but inclined within the flange section 28. The central axis AMI is defined here by the contact surface 34 or the bore and is at an angle -avK to the drivetrain axis AD. Consequently, in the unloaded state, there is a tilting of the gear teeth in the planetary stage 22 and an upward inclination – angle -avK – as shown in Figure 3. In the loaded state, the gearbox 24 is then tilted downwards by the tilting moment MK resulting from the weight force FRG, so that the position shown in Figure 5 is reached, in which the central axis AM2 of the gearbox 24 is coaxial with the central axis AMI of the first gearbox component 12 and coaxial with the drivetrain axis AD.

[0034] Figures 7 and 8 show another embodiment of a gear drive train 10 for compensating the angular tilting caused by the weight force FRG of the gearbox 24. The basic design of the gear drive train 10 differs from the description in Figure 2 with regard to the mounting of the planet carrier 14. The planet carrier 14 is mounted relative to the gearbox 24 via an additional bearing arrangement 38.

[0035] Figure 7 initially shows the unloaded state, in which the gearbox 24 is not subjected to its own weight, so that there are no deformations due to material compliances (cf. Figure 3). A central axis AM3 of the ring gear 30 has a radial offset V. ri opposite the flange section 28 arranged around the central axis AMI. The radial offset V riThe displacement of the ring gear 30 relative to the flange section 28 is vertically upwards. Due to the compliances, among other things, in the bearing arrangements 16 and 38, the gearbox 24 tilts vertically upwards, and its central axis AM2 is inclined upwards by an angle +UVK relative to the central axis AMI of the first gearbox component 12. Figure 8 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. The central axis AM2 of the gearbox 24 now runs coaxially to the central axis AMI of the first gearbox component 12 and coaxially to the drivetrain axis AD. The central axis AMI and the central axis AM3 also have the radial offset V. rito each other. The coaxial orientation of the two central axes AMI and AM2 to each other ensures that there is no tilting of the gear teeth in the planetary stage 22, in particular between ring gear 30 and planet carrier 14.

[0036] In another variant with radial offset, it can alternatively or additionally be provided that the central axis AM2 of the second gear component 20 has a radial offset V r 2 compared to the flange section 28 arranged around the central axis AMI. The radial offset V r The second step here is performed vertically downwards. The same relationships result as described in Figures 7 and 8.

[0037] Reference symbol list

[0038] 10 Transmission drivetrain

[0039] 12 Gearbox component

[0040] 14 PI anetenradträger

[0041] 16 Storage arrangement

[0042] 20 Gearbox component

[0043] 22nd planetary stage

[0044] 24 trunk gearboxes

[0045] 26th planetary stage

[0046] 28 Housing element

[0047] 30 Housing element

[0048] 32 Housing element

[0049] 34 Plant area

[0050] 36 bore

[0051] 38 Storage arrangement

[0052] 100 wind turbines

[0053] 102 Drive string

[0054] 104 Rotor flange

[0055] 106 multi-blade rotor

[0056] 108 Rotor bearing

[0057] 112 Generator

[0058] 114 machine carriers

[0059] 116 Torque support

[0060] 118 Rotor shaft

[0061] 120 rotor bearing housings

[0062] 124 Generator shaft

[0063] 126 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, comprising a first and at least one further gear component (12, 20) each with a central axis (AMI, AM2), wherein the first gear component (12) has at least one planet carrier (14) with planet gears of a first planet stage (22) received therein, a first housing element (28) as a flange section with a received bearing (16) for the planet carrier (14) and a second housing element (30) as a ring gear and the second gear component (20) has at least one further planet and / or spur gear stage (26), characterized in that in an unloaded state, in which a weight force FRG of the at least one further gear component (20) is not acting on this gear component (20), the central axis (AM?) of the at least one further gear component (20) is at an angle (+OIVK) to the drive train axle (AD).

2. Gear drive train (10) according to claim 1, characterized in that in the unloaded state the central axis (AM2) is inclined counterclockwise relative to AMI in the direction of the at least second gear component (20) starting from an intersection point with the central axis (AMI).

3. Gear drive train (10) according to claim 1 or 2, characterized in that in the unloaded state the flange section (28) arranged about the central axis (AMI) or the ring gear (30) has a contact surface (34) and the contact surface (34) is at an angle of 90° 0 +(OIVK) or 90 0 -(OIVK) or below the angle (- QVK) or below the angle (+UVK) to the drivetrain axis AD.

4. Gear drive train (10) according to claim 3, characterized in that the flange section (28) extends over the angle of 90°. 0+(OIVK) The contact surface (34) is attached to the ring gear (30) at the drive shaft axis AD.

5. Gear drive train (10) according to claim 3, characterized in that the contact surface (34) of the flange section (28) which is at the angle (-OIVK) or at the angle (+OIVK) to the drive train axis AD is a bore for receiving the bearing (16) for the planet carrier (14).

6. Gear drive train (10) according to one of claims 1 to 5, characterized in that the planetary gear carrier (14) is mounted via a one-sided guide bearing (16) in the first housing element (28) designed as a flange section or on the side facing away from a first housing element (28) in the housing element (32).

7. Gear drive train (10) according to claim 1 or 2, characterized in that in the unloaded state a central axis (AMS) of the ring gear (30) has a first radial offset (V ri) compared to the flange section (28) arranged around the central axis (AMI).

8. Gear drive train (10) according to claim 1, 2 or 7, characterized in that in the unloaded state the central axis (AM?) of the second gear component (20) has a second radial offset (V r 2) compared to the flange section (28) arranged around the central axis (AMI).

9. Gear drive train (10) according to claim 8, characterized in that in the unloaded state the first radial offset (V r i) opposite to the second radial offset (V r 2) is directed.

10. Gear drive train (10) according to one of claims 1, 2 or 7 to 9, wherein the planetary gear carrier (14) of the first gear component (12) is supported relative to the second gear component (20) by a further bearing (38).

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

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