Planetary gearing having a sealed pitch tube

Abstract

The invention relates to a planetary gearing (10) for a wind turbine (70) driven by means of a rotor (72), comprising: a gearing housing (12) which surrounds an oil-accommodating space (28) for accommodating an oil volume; a plurality of planetary stages (141, 142) which revolve around an axis of rotation AD and which are connected to one another in terms of driving; a pitch tube (34) which is disposed coaxially inside the two planetary stages (141, 142) and which is rotationally rigidly connected to a planet carrier (161) of the first planetary stage (141), wherein the pitch tube (34) is sealed with respect to an exterior of the gearing housing (12) and a volume region (30) is formed between the pitch tube (34) and each of the planetary stages (141, 142). At least a portion (32) of the volume region (30) is sealed with respect to the oil-accommodating space (28). A complex, expensive and fault-prone oil discharge device is rendered unnecessary. In the sealed volume region (30), the pitch tube (34) no longer has any contact with the oil.

Description

[0001] Planetary gear with sealed pitch tube

[0002] Description

[0003] The invention relates to a planetary gear for a wind turbine driven by a rotor, with a gear housing enclosing an oil receiving space for receiving an oil volume, several planetary stages rotating about an axis of rotation AD and connected to one another in a drive manner, a pitch tube arranged coaxially within the two planetary stages and connected in a rotationally fixed manner to a planet carrier of the first planetary stage, wherein the pitch tube is sealed off from an outer side of the gear housing and a volume area is formed between the pitch tube and each of the two planetary stages.

[0004] The tower structure of wind turbines includes, among other things, the rotor shaft, a planetary gear unit, and a generator. The tower structure is usually installed at an angle, so that it is, for example, at a tilt angle of around 6° to a vertical direction, with one rotor flange higher than the generator. As a result of the tilt angle, the pitch tube, which runs centrally through the planetary gear unit, is also at this angle, so that the gear oil runs along the outside of the pitch tube towards the generator and builds up in front of the sealed housing bushing. Draining the oil that collects there is difficult and in some cases even impossible. However, draining the oil is necessary because the oil can boil over and thus coke, which can damage the structures.DE 10 2010 064647 B3 describes a design in which the planetary gear has a pitch tube with an annular channel. The annular channel surrounds the pitch tube and serves as an oil channel to supply the planetary gear bearings with oil. This oil channel is connected at one end to a tooth gap within the housing volume via an oil bore.

[0005] Conventionally, certain transmission configurations provide a hole in this area through which the oil can at least largely drain away, thus protecting the seal from overheating and damage. Draining the oil at the lower end of the pitch tube also proves difficult due to the rotating generator rotor. With modified transmission configurations, the hole can no longer be placed in the area where the oil collects, making it necessary to prevent the oil from entering this area.

[0006] The task is to show measures that can be used to prevent oil accumulation at the generator-side end of the pitch tube.

[0007] This object is achieved by a planetary gear mechanism having the features of claim 1. Preferred embodiments are specified in the subclaims and the following description, each of which, individually or in combination, may represent an aspect of the invention. If a feature is presented in combination with another feature, this merely serves to simplify the illustration 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 planetary gear for a wind turbine driven by a rotor, with a gear housing enclosing an oil receiving space for receiving an oil volume, a plurality of planetary stages rotating about an axis of rotation AD and drivingly connected to one another, a pitch tube arranged coaxially within the planetary stages and connected in a rotationally fixed manner to a planet carrier of the first planetary stage, wherein the pitch tube is sealed off from an outer side of the gear housing and a volume region is formed between the pitch tube and each of the plurality of planetary stages, wherein at least a partial section of the volume region is sealed off from the oil receiving space.

[0009] The oil intake chamber is basically the interior of the gearbox housing in which no machine parts are located and in which oil, a volume of oil or even oil mist can be found either when the machine is at a standstill or in one of the possible operating states.

[0010] The volume area to be sealed can be defined by at least one outer circumferential surface of the pitch tube and one inner circumferential surface of the sun gears of the two planetary stages. Sealing to the sides is provided by the planet carrier on the one hand, or the hollow shaft or sun gear on the other.

[0011] The first section of the volume area sealed off from the oil intake chamber is expediently the generator-side section of the volume area. This relocates the location of potential oil accumulation further toward the center of the gearbox housing, where simple measures can eliminate or at least reduce the oil accumulation, or where continuous mixing of the oil accumulation can be achieved, preventing boiling over.

[0012] A complex, expensive, and error-prone oil drainage system is eliminated. The pitch tube no longer has contact with the oil in the sealed area. Replacing the pitch tube during maintenance is significantly easier, and the electrical insulation of the planetary gear from the pitch tube or generator is significantly easier to implement.

[0013] In a further preferred embodiment, the partial section of the volume area is sealed from the oil receiving chamber by a sealing element located between the sun gear of the subsequent planetary gear stage and the pitch tube. This ensures that the penetration of oil from the oil receiving chamber into the partial section of the volume area is prevented or at least reduced to a minimum. In particular, in a specific embodiment, it can be provided that the sealing element is held in a rotationally fixed manner relative to the sun gear.

[0014] In a further preferred embodiment, at least one further subsection of the volume region is provided, sealed from the oil receiving chamber, wherein the at least two subsections have different outer radii. In this case, the two subsections can together constitute the entire volume region. One of the two subsections can at least approximately coincide in its axial extent with the first planetary stage, and the other subsection can at least approximately coincide in its axial extent with the subsequent planetary stage.In a possible concrete embodiment, the volume area, consisting of at least two subsections, is sealed from the oil receiving chamber by a first sealing element arranged between a sun gear of the first planetary stage and the sun gear of the subsequent planetary stage and by a second sealing element arranged between the sun gear and the planet carrier of the first planetary stage.

[0015] In another possible embodiment, a sleeve element extending coaxially with a sun gear of the first planetary stage is arranged in the volume region, wherein the volume region is sealed by a first sealing element arranged between the sun gear of the second planetary stage and the sleeve element, and by a second sealing element arranged between the planet carrier of the first planetary stage and the sleeve element. In a practical embodiment, it can be provided that the two sealing elements are held in a rotationally fixed manner on the sleeve element.

[0016] The problem is also solved by a drive train for a wind turbine for the torque-transmitting connection of a rotor to a generator, comprising a main bearing unit, a main shaft mounted in the main bearing unit, a gearbox driven via the main shaft, and a generator drivingly connected to the gearbox, wherein the gearbox is designed as described. A planet carrier of the planetary stage is mounted indirectly via the main shaft relative to the main bearing unit and centered relative to the gearbox housing.

[0017] The object is also achieved by a wind turbine comprising a rotor flange with a rotor and a generator, wherein a drive train is provided which is held on a machine carrier and connects the rotor flange to the generator, wherein the drive train is designed as described.

[0018] The invention will be explained below 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:

[0019] Fig. 1 : a schematic representation of a wind turbine in a possible design, Fig. 2: a cross-section through the gearbox with two planetary stages,

[0020] Fig. 3: a schematic representation of a conventional arrangement and sealing of a pitch tube within the two planetary stages and

[0021] Fig. 4 to 6: schematic representations of possible designs of a seal of the volume area against the oil receiving space.

[0022] Figure 1 shows a schematic, not-to-scale representation of a possible embodiment of a wind turbine 100. A key element of the wind turbine 100 is a drive train 102, which structurally comprises a rotor flange 104 with a rotor 106, a main bearing unit 108, a planetary gear 10, and a generator 112. A machine support 114 supports at least the main bearing unit 108 and the generator 112 against the ground via a tower 116 (not shown).

[0023] The main bearing unit 108 comprises a main shaft 118, which is mounted via a rolling bearing arrangement 16 relative to a bearing housing 120 of the main bearing unit 108 for rotation about a rotational axis D. The rotor flange 104 is held at one end of the main shaft 118, and the rotor 106 is held thereto. The other end of the main shaft 118 is drivingly connected to the transmission 10 via a coupling 122 in order to introduce a drive torque generated by the rotor 106 into the transmission 10. The transmission 10 can be designed as a planetary transmission with one or more planetary stages. The transmission 10 is drivingly connected to the generator 112 via a generator shaft 124. The bearing housing 120 is connected to the transmission 10 via a flange 126.

[0024] Figure 2 shows a cross-section through a planetary gear 10, which in this case is designed with two planetary stages 14i, 142. The planetary gear 10 comprises the gear housing 12, in which the two planetary stages 14i, 142 rotate about a rotational axis AD. Each planetary stage 14i, 142 has a planet carrier 16 and a ring gear 20. The planet carrier 16 is indirectly drive-connected to the rotor 106, wherein the planet carrier 16 has a plurality of planet gears 18 rotating with the planet carrier 16 and alternately meshing with the ring gear 20 and a sun gear 22. The sun gear 22 of the first planetary stage 14i is in turn drive-connected to a planet carrier 16 of the second planetary stage 142, which requires no further description here. Not shown in Figure 2 is a pitch tube arranged coaxially within the two planetary stages 14i, 142 and connected in a rotationally fixed manner to the planet carrier 16i of the first planetary stage 14i.This is illustrated and explained using the following figures.

[0025] Figure 3 shows a purely schematic representation of a conventional

[0026] Arrangement and sealing of a pitch tube 34 arranged within the two planetary stages 14i, 142. Shown are the planet carrier 16i of the first planetary stage 14i and the pitch tube 34, both of which rotate in the transmission housing 12 at a speed m in one operating situation. For the first planetary stage 14i, the sun gear 22i is shown, which rotates at a second speed n2 in one operating situation. For the second planetary stage 142, only the corresponding sun gear 222 is shown, which rotates at a third speed ns in one operating situation. The transmission housing 12 encloses an oil receiving chamber 28, in which, for example, an oil reservoir and, in particular, the spray oil that forms in an operating situation is held. In addition to the oil receiving chamber 28, a volume region 30 is formed, which is located between the pitch tube 34 and the two planetary stages 14i, 142.The volume area 30 is delimited at least by an outer circumferential surface 36 of the pitch tube 34 and a respective inner circumferential surface 38 of the sun gears 22 of the two planetary stages 14i, 142.

[0027] The volume region 30 can in turn be divided into a first subsection 32i, located between the pitch tube 34 and the second planetary stage 142, and a second subsection 32i, located between the pitch tube 34 and the first planetary stage 14i. Further or other subdivisions of the volume region 30 into subsections can be made if appropriate. The first subsection 32i is sealed to the outside on the generator side by a sealing element 50 between the sun gear 222 of the second planetary stage 142 and the pitch tube. In an operating state, the oil in the oil receiving chamber 28 can flow unhindered into the volume region 30, in particular between the planet carrier 16i and the sun gear 22i of the first planetary stage 14i and this sun gear 22i and the sun gear 222 of the second planetary stage 142.As a result of the inclined installation position of the tower structure, which has already been described but is not shown here, the oil collects in the first sub-section 32i during operation, in particular in front of the sealing element 50, since it is retained by the latter. The oil collecting in front of the sealing element 24 is designated by the reference numeral 26 in Figure 3, but this is only for illustrative purposes. Figure 4 shows a first embodiment of a seal for the volume region 30 with respect to the oil receiving chamber 28. In this case, it is provided that the first sub-section 32i of the volume region 30 is sealed with respect to the oil receiving chamber 28 by means of a sealing element 40 located between the sun gear 22 of the second planetary stage 142 and the pitch tube 34. The sealing element 40 can be held in a rotationally fixed manner with respect to the sun gear 222, i.e., be attached to it and rotate at the speed of the sun gear 222.Due to this positioning of the sealing element 40, no oil can enter the first section 32i of the volume area 30, so that in an operating state no oil accumulation forms in front of the sealing element 24.

[0028] Figure 5 shows a further embodiment of a seal for the volume region 30 relative to the oil receiving chamber 28. It is provided that the volume region 30 is sealed relative to the oil receiving chamber 28 by a first sealing element 42i arranged between the sun gear 22i of the first planetary stage 14i and the sun gear 222 of the second planetary stage 14i, and by a second sealing element 422 arranged between the sun gear 22i and the planet carrier 16 of the first planetary stage 14i. Thus, the entire volume region 30 is sealed against oil ingress from the oil receiving chamber 28.

[0029] Figure 6 shows yet another embodiment of a seal for the volume region 30 relative to the oil receiving chamber 28. It is provided that a sleeve element 44 extending coaxially with the sun gear 22i of the first planetary stage 14i is arranged in the volume region 30, wherein the volume region 30 is sealed by a first sealing element 46i arranged between the sun gear 22i of the second planetary stage 14i and the sleeve element 44, and by a second sealing element 46i arranged between the planet carrier 16i of the first planetary stage 14i and the sleeve element 44. In an alternative embodiment (not shown), it can be provided that the sleeve element 44 is arranged coaxially within the sun gear 22 of at least one further or all planetary stages 14. List of reference symbols

[0030] 10 Pl anetengetri eb e

[0031] 12 Gearbox housing

[0032] 14 planetary stage

[0033] 16 planet carriers

[0034] 18 planetary gears

[0035] 20 ring gear

[0036] 22 Sun gear

[0037] 24 Sealing element

[0038] 26 Oil accumulation

[0039] 28 Oil intake chamber

[0040] 30 volume range

[0041] 32 subsection

[0042] 34 Pitch tube

[0043] 36 outer peripheral surface

[0044] 38 inner circumferential surface

[0045] 40 Sealing element

[0046] 42 Sealing element

[0047] 44 Sleeve element

[0048] 46 Sealing element

[0049] 100 wind turbines

[0050] 102 drive train

[0051] 104 Rotor flange

[0052] 106 multi-blade rotor

[0053] 108 Main bearing unit

[0054] 110 gearboxes

[0055] 112 Generator

[0056] 114 Machine carrier 116 Tower

[0057] 118 Main shaft

[0058] 120 bearing housings

[0059] 122 Clutch 124 Generator shaft

Claims

Patent claims 1. Planetary gear unit (10) for a wind turbine (70) driven by a rotor (72), comprising a gear housing (12), the gear housing (12) enclosing an oil receiving chamber (28) for receiving an oil volume, a plurality of planetary stages (14i, M2) rotating about a rotational axis AD and drive-connected to one another, a pitch tube (34) arranged coaxially within the planetary stages (14i, M2) and connected in a rotationally fixed manner to a planet carrier (161) of the first planetary stage (14i), the pitch tube (34) being sealed off from an outer side of the gear housing (12), and a volume region (30) being formed between the pitch tube (34) and each of the plurality of planetary stages (14i, M2), characterized in that at least a partial section (32) of the volume region (30) is sealed off from the oil receiving chamber (28).

2. Planetary gear (10) according to claim 1, characterized in that the at least one partial section (32) of the volume region (30) is sealed off from the oil volume of the oil receiving space (28).

3. Planetary gear (10) according to claim 1 or 2, characterized in that the at least one partial section (32) is sealed off from the oil receiving space (28) in order to prevent an exchange of the oil volume between the oil receiving space (28) and the volume region (30).

4. Planetary gear (10) according to one of claims 1 to 3, characterized in that the volume region (30) is surrounded at least by an outer circumferential surface (36) of the Pitch tube (34) and a respective inner circumferential surface (38) of the sun gears (22) of the plurality of planetary stages (14i, M2).

5. Planetary gear (10) according to one of claims 1 to 4, characterized in that the partial section (32i) of the volume region (30) is sealed off from the oil receiving space (28) by means of a sealing element (40) located between the sun gear (22) of the second planetary stage (M2) and the pitch tube (34).

6. Planetary gear (10) according to claim 5, characterized in that the sealing element (40) is held in a rotationally fixed manner relative to the sun gear (22).

7. Planetary gear (10) according to one of claims 1 to 6, characterized in that at least one further partial section (322) of the volume region (30) is provided, which is sealed off from the oil receiving space (28), wherein the at least two partial sections (32i, 322) are arranged axially offset from one another, in particular adjoin one another axially.

8. Planetary gear (10) according to claim 7, characterized in that the volume region (30) is sealed off from the oil receiving space (28) by means of a first sealing element (42i) arranged between a sun gear (22) of the first planetary stage (14i) and the sun gear (22) of the second planetary stage (M2) and by means of a second sealing element (422) arranged between the sun gear (22) and the planet carrier (16) of the first planetary stage (14i).

9. Planetary gear (10) according to one of claims 1 to 8, characterized in that in the volume region (30) a sleeve element (44) extending coaxially to the pitch tube (34) is arranged, wherein the volume region (30) is sealed via a first sealing element (46i) arranged between the sun gear (22) of a second of the plurality of planetary stages (M2) and the sleeve element (44) and via a between the planet carrier (16) of a first of the plurality of planetary stages (14i) and the sleeve element (44) is sealed.

10. Planetary gear (10) according to claim 9, characterized in that the two sealing elements (46i, 462) are held on the sleeve element (44) in a rotationally fixed manner.

11. Planetary gear (10) according to claim 9 or 10, characterized in that the sleeve element (44) is arranged coaxially within the sun gear (22) of a first of the plurality of planetary stages (14i).

12. Planetary gear (10) according to claim 11, characterized in that the sleeve element (44) is arranged coaxially within the sun gear (22) of at least one further one of the plurality of planetary stages (14).

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) and a main shaft (118) and a gear (10) driven via the main shaft (118), characterized in that the gear (10) is designed as a planetary gear according to one of the preceding claims.

14. Wind turbine (100), comprising a rotor flange (104) with a rotor (106) and a generator (112), wherein a drive train (102) is provided which is held on a machine carrier (114) and connects the rotor flange (104) to the generator (112), characterized in that the drive train (102) is designed according to claim 13.

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