Folded sun shaft

Abstract

The invention relates to an assembly (101, 201 301, 401) with a sun shaft (105), a sun gear (103), which is connected for conjoint rotation with the sun shaft (105), and a hub (109). The transmission (101, 201 301, 401) has a hollow shaft (107), which is connected for conjoint rotation with the sun shaft (105) in a first point of connection (113, 203) and for conjoint rotation with the hub (109) in a second point of connection (115, 205); wherein, starting from the first point of connection (113, 203), the second point of connection (115, 205) is offset axially in the direction of the sun gear (103).

Description

[0001] Folded solar wave

[0002] The invention relates to an arrangement according to the preamble of claim 1, a wind turbine gearbox according to claim 14 and a use according to claim 16.

[0003] Wind turbines with integrated drive trains are known from the prior art. For example, US 2010 329 867 A2 discloses an integrated drive train. The rotor of a generator is fixed to a hub, which is part of a gearbox. This hub is connected to a sun shaft via splines.

[0004] The invention is based on the object of making available a drive train that is improved compared to the prior art, among other things for wind turbines.

[0005] This object is achieved by an arrangement according to claim 1, a wind turbine gearbox according to claim 14 and a use according to claim 16. Preferred developments are contained in the subclaims and result from the following description and the figures.

[0006] The arrangement according to the invention comprises a sun shaft, a sun gear, and a hub. A sun gear is designed for use as part of a planetary stage. The planetary stage further includes a ring gear, one or more planet gears, and a planet carrier. The planet gears are rotatably mounted in the planet carrier and mesh with the ring gear and / or the sun gear. Preferably, exactly two of the three transmission elements—ring gear, planet carrier, and sun gear—are rotatably mounted, while the third transmission element is fixed to the housing. In particular, the sun gear and the planet carrier can be rotatably mounted, and the ring gear can be fixed to the housing.

[0007] In this case, the sun gear is connected to the sun shaft in a rotationally fixed manner, meaning that it cannot rotate relative to the sun gear. In particular, the sun gear can be integrally connected to the sun shaft or joined to it with a force-fit, form-fit, and / or material fit.

[0008] According to the technical understanding, a hub refers to a device connected to a shaft, axle, or journal. In this case, the hub is connected to a hollow shaft. According to the invention, this hollow shaft is connected in a first connection point to the sun shaft in a rotationally fixed manner and in a second connection point to the hub.

[0009] The term connection point refers to a location in which a force-fitting, form-fitting and / or material-fitting joint is formed between two connection partners, in this case between the hollow shaft and the sun shaft or the hub.

[0010] The joints at the first connection point and the second connection point are each rotationally fixed. This creates a rotationally fixed connection between the sun gear and the hollow shaft via the first connection point. A rotationally fixed connection between the hollow shaft and the hub exists via the second connection point. As a result, the sun gear and the hub are also rotationally fixed. This allows a torque flow to be transmitted from the sun gear via the sun gear and the hollow shaft to the hub, or a torque flow in the opposite direction from the hub via the hollow shaft and the sun gear to the sun gear.

[0011] The invention provides that the second connection point is arranged axially offset from the first connection point, i.e., in the direction of a rotational axis of the sun gear, the sun shaft, the hollow shaft, and the hub, toward the sun gear. Thus, there is an axial offset between the two connection points.

[0012] The axial offset is limited by the planetary stage to which the sun gear belongs. Accordingly, the second connection point is preferably arranged axially offset from the sun gear toward the first connection point. The second connection point is then located axially between the sun gear and the first connection point.

[0013] The axially offset arrangement of the two connection points results in a convolution of the torque flow described above. At the first connection point, its direction is reversed. Compared to a direct torque flow between the sun gear and the hub, the convolution of the torque flow at the first connection point increases the distance the torque must travel between the sun gear shaft and the hub. As a result, the torsional stiffness is reduced.

[0014] The invention is based on the discovery that reduced torsional stiffness improves the vibration behavior of the assembly. In particular, noise emissions resulting from the transmission of torsional vibrations from the planetary gear to the hub are reduced. Since the reduction in torsional stiffness is achieved by convolving the torque flow, the original load-bearing capacity of the torque-transmitting connection between the sun gear and the hub is maintained.

[0015] In a preferred refinement, the sun shaft extends into the hollow shaft, so that one end of the sun shaft is located inside the hollow shaft, or the sun shaft extends through the hollow shaft. In the latter case, both end faces of the sun shaft are located outside the hollow shaft. In both cases, a section of the sun shaft is arranged inside the hollow shaft, i.e., in a cavity enclosed by the hollow shaft. This refinement results in a nested arrangement of the sun shaft and the hollow shaft, thus resulting in the convolution of the torque flow described above.

[0016] In a preferred embodiment, the hub is rotatably mounted in a housing of the transmission or a structure fixed to the housing, i.e., a structure that is rigidly fixed in the housing, i.e., without the possibility of relative movement. This means that the hub is, on the one hand, rotatable relative to the housing and, on the other hand, is supported in the housing via one or more bearings. Preferably, the hub is supported in the housing or the structure fixed to the housing exclusively via these bearings.

[0017] The improved bearing design of the hub enables an integrated construction of the gearbox and a generator. A generator rotor can then be fixed to the hub. The rotor is then at least partially, preferably completely or exclusively, supported by the hub. In the latter case, no additional bearings are present to support the rotor besides the aforementioned bearings supporting the hub in the housing or the structure fixed to the housing.

[0018] In a preferred embodiment, the first connection point is located within the hollow shaft, i.e., in a cavity enclosed by the hollow shaft. This allows the first connection point to be realized with a force-locking connection. A force-locking connection between the sun shaft and the hollow shaft at the first connection point is achieved, for example, by a clamping set pushed onto the hollow shaft. With a force-locking connection, the sun shaft and the hollow shaft can be rotated relative to each other before they are connected to each other in a rotationally fixed manner by the force-locking connection. This is advantageous during assembly.

[0019] Alternatively, in a further preferred embodiment, the first connection point formed within the hollow shaft as part of an arrangement can be designed as a spline. A spline allows the sun gear to tilt relative to the hollow shaft about a tilt axis that runs orthogonal to the rotational axis of the sun gear and / or the hollow shaft. This tilt allows for radial bearing deviations of the sun gear for the purpose of load balancing within the planetary stage.

[0020] In a preferred embodiment, the second connection point is located within the hub, i.e., in a cavity enclosed by the hub. The second connection point is preferably designed as a spline. This is advantageous for assembly, as the hollow shaft can be easily inserted into the hub for assembly.

[0021] In a preferred embodiment, the first connection point is not located within the hollow shaft, but rather on a front side of the hollow shaft. The hollow shaft then extends from the first connection point toward the sun gear. The arrangement of the first connection point according to the embodiment is advantageous because it makes the first connection point particularly accessible for assembly and disassembly purposes.

[0022] This makes it possible, for example, to design the first connection point as a screw flange according to a further preferred embodiment. The screw flange consists of a first flange and a second flange, which are preferably screwed together. According to the embodiment, the sun shaft has the first flange and the hollow shaft has the second flange.

[0023] In order to enable particularly good accessibility of the second connection point for assembly and disassembly purposes, in a preferred development said second connection point is arranged on a second end face of the hollow shaft opposite the first end face and / or on an end face of the hub.

[0024] Even with a front-end arrangement of the second connection point, according to a further preferred development, the second connection point can be implemented as a flange connection. This flange connection is formed by a third flange and a fourth flange, which are preferably screwed together. The hollow shaft has the third flange, and the hub has the fourth flange.

[0025] Preferably, the hollow shaft is further developed with one or more recesses. The recesses make it possible to specifically reduce the torsional rigidity of the hollow shaft in accordance with the invention. The sun shaft can be constructed in one piece or comprise multiple parts. In a corresponding preferred development, the sun shaft comprises a first partial shaft and a second partial shaft. The first partial shaft and the second partial shaft are separate parts that are not integrally connected to one another.

[0026] The first sub-shaft includes the sun gear. The sun gear can be integrally connected to the first sub-shaft or joined to it by force, form, and / or material connection. The second sub-shaft, together with the hollow shaft, forms the first connection point. The hollow shaft is thus non-rotatably connected to the second sub-shaft at the first connection point.

[0027] The two sub-shafts, in turn, are connected to each other via splines for rotational stability. The splines allow the two sub-shafts to tilt relative to each other around a tilt axis that runs orthogonal to a rotational axis of the first sub-shaft and / or the second sub-shaft. Such tilting is accompanied by a radial positional deviation of the sun gear. This enables load balancing within the planetary stage.

[0028] In contrast, the axial position of the second partial shaft is preferably fixed. For this purpose, in a preferred embodiment, the second partial shaft is axially supported against an inner circumferential surface of the hub. According to the embodiment, the inner circumferential surface forms an axial abutment against the second partial shaft. An axial positional deviation of the second partial shaft is prevented by contact between the second partial shaft and the inner circumferential surface of the hub.

[0029] The arrangement is preferably further developed as a wind turbine gearbox. Wind turbine gearboxes are characterized, among other things, by particularly high torque loads. For example, an input shaft of the gearbox can be loaded with more than 3,000 kNm, 5,000 kNm, or 10,000 kNm during operation. Against this background, further development as a wind turbine gearbox seems surprising, since reduced torsional stiffness usually goes hand in hand with reduced torque load capacity. However, the original load capacity of a wind turbine gearbox with this further development is maintained due to the convolution of the torque flow.

[0030] In a wind turbine gearbox according to the invention, the first connection point and preferably also the second connection point are arranged on the generator side or offset in the wind direction, starting from the sun gear. Conversely, the second connection point is arranged on the rotor side or offset from the first connection point, opposite the wind direction.

[0031] In the wind turbine gearbox according to the invention, the hub is preferably designed as a generator hub. This means that the hub is connected or connectable to a rotor of a wind turbine generator. This is particularly advantageous because there is free space within the generator for the convolution of the torque flow.

[0032] An inventive use of the wind turbine gearbox according to the further development serves to reduce the noise emissions of a wind turbine, in particular to reduce noise emissions due to torsional vibrations transmitted between the generator and the gearbox.

[0033] Preferred embodiments of the invention are illustrated in the figures. Corresponding reference numerals indicate identical or functionally equivalent features. In detail:

[0034] Fig. 1 shows a nested shaft arrangement with a simple hollow shaft;

[0035] Fig. 2 shows a nested shaft arrangement with flanges;

[0036] Fig. 3 a nested shaft arrangement with clamping set; and

[0037] Fig. 4 shows a nested shaft arrangement with a two-part sun shaft. The shaft assemblies 101, 201, 301, 401 shown in Figs. 1 to 4 each comprise a sun gear 103, a sun shaft 105, a hollow shaft 107, and a hub 109.

[0038] The sun gear 103 is integrally connected to the sun shaft 105. The sun shaft 105 is rotationally connected to the hub 109 via the hollow shaft 107. This, in turn, is mounted in a housing extension 111, which is rigidly fixed in a housing 113.

[0039] According to Fig. 1, the hollow shaft 107 can be connected to the sun shaft 105 and the hub 109 via splines 113, 115. A first spline 113 is formed by an external toothing of the sun shaft 105 and an internal toothing of the hollow shaft 107. The external toothing and the internal toothing are aligned coaxially with each other and mesh with each other, creating a rotationally fixed connection between the sun shaft 105 and the hollow shaft 107.

[0040] A second spline 115 is formed by an external spline of the hollow shaft 107 and an internal spline 109 of the hub. These splines are also coaxially aligned and mesh with each other. This creates a rotationally fixed connection between the hollow shaft 107 and the hub 109.

[0041] The first spline 113 and the second spline 115 are axially offset from one another. Starting from the first spline 113, the second spline 115 is axially offset toward the sun gear 103. Accordingly, the second spline 115 is located axially between the sun gear 103 and the first spline 113.

[0042] Due to the axially offset arrangement of the first spline 113 and the second spline 115, the torque flow to be transmitted does not run directly between the sun gear 103 and the hub 109. Instead, the torque flow runs between the sun gear 113 and the first spline 103 via the sun shaft 105, and between the first spline 113 and the second spline 115 via the hollow shaft 107. In the first spline 113, the axial direction of the torque flow is reversed. This lengthens the path of the torque flow.

[0043] This reduces the torsional stiffness of the rotationally fixed connection of the sun gear 103 to the hub 109. As a result, the transmission of undesirable torsional vibrations between the sun gear 103 and the hub 109 is reduced.

[0044] In a second shaft arrangement 201 shown in Fig. 2, the first spline 113 and the second spline 115 are replaced by a first flange connection 203 and a second flange connection 205. The sun shaft 105 and the hollow shaft 107 are screwed together in the first flange connection 203. Similarly, the hollow shaft 107 and the hub 109 are screwed together in the second flange connection 205.

[0045] The first flange connection 203 and the second flange connection 205 are arranged on opposite end faces of the hollow shaft 107. The second flange connection 205, in turn, is located on one end face of the hub 109.

[0046] The sun gear 103 and the first spline 203 are arranged at axially opposite ends of the sun shaft 105. This results in an axially offset arrangement of the second connecting flange 105, starting from the first connecting flange 203 in the direction of the sun gear 103. The second connecting flange 205 is located axially between the sun gear 103 and the first connecting flange 203.

[0047] In the area of ​​the first connecting flange 203, the sun shaft 105 forms a projection 207 that extends radially outward from the rest of the sun shaft 105. The hollow shaft 107 is screwed to the projection 207 in the first connecting flange 203. This allows the sun shaft 105 to be installed or removed for assembly, maintenance, or repair purposes.

[0048] A third shaft arrangement 301 shown in Fig. 3 has instead of the first

[0049] Flange connection 203 has a clamping set 303. The clamping set 303 is arranged on an outer surface of the hollow shaft 107. It exerts a radial force on the outer surface of the hollow shaft 107, so that a force-locking connection is established between the hollow shaft 107 and the sun shaft 105.

[0050] A force-locking connection has the advantage over a form-locking connection that the sun shaft 105 and the hollow shaft 107 can be freely rotated relative to each other before the clamping set 301 is tightened. This facilitates assembly.

[0051] Since the sun shaft 105 is longer than with a direct coupling to the hub 109, not only the torsional rigidity is reduced, but also the rigidity in the radial direction. This can result in undesirable positional deviations of the sun shaft 105 in the radial direction or radial vibrations. This can be avoided by supporting the sun shaft 105 in the hub 109.

[0052] Specifically, the sun shaft 105 is supported against an inner surface of the hub 109. This is possible because the sun shaft 105 and the hub 109 are connected to each other in a rotationally fixed manner and therefore rotate at the same speed.

[0053] To support the sun shaft 105 in the hub, the sun shaft 105 has a thickening 305 according to Fig. 3. In the area of ​​the thickening 303, the sun shaft 105 rests against an inner surface of the hub 109.

[0054] According to Figs. 1 to 3, the sun gear 103 and the sun shaft 105 are constructed as a single piece. Alternatively, the sun shaft 105 may consist of separate parts 105a, 105b, as shown in Fig. 4.

[0055] A first part 105a of the sun shaft 105 and a second part 105b of the sun shaft 105 are connected to one another in a rotationally fixed manner via a spline 403. The first part 105a of the sun shaft 105 forms an external toothing of the spline 401. An internal toothing of the spline 401 is formed by the second part 105b of the sun shaft 105. In the area of ​​the spline 403, the sun shaft 105 forms a thickened portion 305. In this thickened portion 303, the second part 105b of the sun shaft 105 is supported radially against the hub 109.

[0056] The first part 105a of the sun shaft 105 is tiltable relative to the second part 105b of the sun shaft 105 in the spline 403. As a result, the sun gear 103 is radially movable. This enables load balancing in a planetary stage comprising the sun gear 103 by adjusting the radial position of the sun gear 103 to tolerance-related dimensional deviations within the planetary stage.

[0057] The hollow shaft 107 can have recesses, as in a fourth shaft arrangement 401 shown in Fig. 4. This allows the torsional rigidity of the hollow shaft 107 to be reduced in a targeted manner.

[0058] In the area of ​​the second flange connection 205, the hollow shaft 107 can be bolted directly to the hub 109, as shown in Fig. 3. Alternatively, as shown in Fig. 4, a gap runs between the hub 109 and the hollow shaft 107. This gap serves to accommodate a generator. In this case, the hub 109, the rotor of the generator, and the hollow shaft 107 are bolted together in the area of ​​the second flange connection 205.

[0059] Reference number first shaft arrangement sun gear

[0060] Sun wave a first part b second part

[0061] hollow shaft

[0062] hub

[0063] Shell extension

[0064] Housing first spline second spline second shaft arrangement first flange connection second flange connection projection third shaft arrangement clamping set

[0065] clamping set

[0066] Thickening fourth shaft arrangement spline

Claims

Patent claims 1. An arrangement (101, 201, 301, 401) comprising a sun shaft (105), a sun gear (103) which is rotationally connected to the sun shaft (105), and a hub (109); characterized by a hollow shaft (107) which is rotationally connected to the sun shaft (105) at a first connection point (113, 203) and to the hub (109) at a second connection point (115, 205); wherein the second connection point (115, 205) is arranged axially offset from the first connection point (113, 203) in the direction of the sun gear (103).

2. Arrangement (101, 201, 301, 401) according to claim 1; characterized in that a portion of the sun shaft (105) is arranged within the hollow shaft (107).

3. Arrangement (101, 201, 301, 401) according to one of the preceding claims; characterized in that the hub (109) is rotatably mounted in a housing (113) or in a structure (111) fixed to the housing.

4. Arrangement (101) according to one of the preceding claims; characterized in that the first connection point (113) is arranged within the hollow shaft (107).

5. Arrangement (101) according to the preceding claim; characterized in that the first connection point (113) is designed as a spline.

6. Arrangement (101) according to one of the preceding claims; characterized in that the second connection point (115) is arranged within the hub (109).

7. Arrangement (201 301 , 401 ) according to one of claims 1 to 3; characterized in that the first connection point (203) is arranged on a first end face of the hollow shaft (107).

8. Arrangement (201, 301, 401) according to the preceding claim; characterized in that the sun shaft (105) has a first flange and the hollow shaft (107) has a second flange; wherein the first flange and the second flange form the first connection point (203).

9. Arrangement (201 301 , 401 ) according to one of claims 1 to 3, 6 or 7; characterized in that the second connection point (205) is arranged on a second end face of the hollow shaft (107) and / or on an end face of the hub (109).

10. Arrangement (201, 301, 401) according to the preceding claim; characterized in that the hollow shaft (107) has a third flange and the hub (109) has a fourth flange; wherein the third flange and the fourth flange form the second connection point (205).

11. Arrangement (401) according to one of the preceding claims; characterized in that the hollow shaft (107) has one or more recesses.

12. Arrangement (401) according to one of the preceding claims; characterized in that the sun shaft (105) comprises a first partial shaft (105a) and a second partial shaft (105b); wherein the first partial shaft (105a) has the sun gear (103); wherein the hollow shaft (107) is connected in the first connection point (203) in a rotationally fixed manner to the second Partial shaft (105b) is connected; and wherein the first partial shaft (105a) and the second partial shaft (105b) are connected to one another in a rotationally fixed manner via a spline (403).

13. Arrangement (401) according to the preceding claim; characterized in that the second partial shaft (105b) is supported radially against an inner circumferential surface of the hub (109).

14. Wind turbine gearbox with the features of an arrangement (101, 201, 301, 401) according to one of the preceding claims.

15. Wind turbine gearbox according to the preceding claim; characterized in that the hub (109) is designed as a generator hub.

16. Use of a wind turbine gearbox according to one of claims 13 or 14 for reducing the noise emission of a wind turbine.

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