WIND TURBINE

Abstract

A wind turbine includes a nacelle with a main bearing tilted with its rotation axis towards the horizontal axis and including an inner and outer ring, wherein the main bearing is a slide bearing and the inner ring is stationary while the outer ring rotates, with the main bearing being lubricated, and with the outer ring including a first and a second sealing means, wherein the first sealing means is due to the tilt of the main bearing lower than the second sealing means, wherein a stationary leakage lubrication fluid collection means is provided adapted for collecting lubrication fluid, wherein the outer ring is provided with one or more axial bores connecting a leakage lubrication fluid collection area to the leakage lubrication fluid collection means and wherein each sealing means includes a groove accommodating a sealing element and a sealing element carrier ring.

Claims

1. A wind turbine comprising a nacelle with at least one main bearing tilted with its rotation axis towards the horizontal axis and comprising an inner ring and an outer ring, wherein the main bearing is a slide bearing and the inner ring is stationary while the outer ring rotates around the inner ring, with the main bearing being lubricated with a lubrication fluid, and with the outer ring comprising a first sealing means and a second sealing means arranged at both sides of the outer ring for sealing to the inner ring and extending around the outer ring, wherein the first sealing means is due to the tilt of the main bearing lower than the second sealing means, wherein a stationary leakage lubrication fluid collection means is provided adjacent to the first sealing means adapted for collecting lubrication fluid leaking from the first sealing means and the second sealing means, wherein the outer ring is provided with one or more axial bores connecting a leakage lubrication fluid collection area adjacent to the second sealing means to the leakage lubrication fluid collection means and wherein each sealing means comprises a groove accommodating a sealing element and a sealing element carrier ring having a fold and a clamp ring attached to the carrier ring closing the fold to build the groove and clamping the sealing means in the groove.

2. The wind turbine according to claim 1, wherein the leakage lubrication fluid collection area is a collection groove extending around the outer ring.

3. The wind turbine according to claim 1, wherein the leakage lubrication fluid collection means is arranged at the inner ring.

4. The wind turbine according to claim 1, wherein the leakage lubrication fluid collecting means is a collector ring extending around the main bearing.

5. The wind turbine according to claim 1, wherein a drip edge ring is arranged at the outer ring extending to or into the leakage lubrication fluid collection means.

6. The wind turbine according to claim 1, wherein the clamp ring of the second sealing means comprises the leakage lubrication fluid area.

7. The wind turbine according to claim 1, wherein a sealing element is arranged at the clamp ring sealing the collection groove to the inner ring.

8. The wind turbine according to claim 1, wherein the bore communicates with the leakage lubrication fluid collection area, and extends from the clamp ring through the sealing element carrier ring of the second sealing means, the outer ring and through the sealing element carrier and the clamp ring of the first sealing means and is open to the leakage lubrication fluid collection means.

9. The wind turbine according to claim 1, wherein the clamp ring and the element carrier ring are fixed to the outer ring by means of several bolt connections.

10. The wind turbine according to claim 1, wherein at least one sealing ring is arranged each between the clamp ring and the element carrier ring and the element carrier ring and the outer ring, which sealing rings arranged in respective grooves.

11. The wind turbine according to claim 1, wherein several bores connecting the leakage lubrication fluid collection area with the leakage lubrication fluid collection means, which bores are equally distributed around the circumference of the outer ring.

12. The wind turbine according to claim 1, further comprising an automatic lubrication arrangement with a lubrication circuit with a pump for circulating the lubrication fluid, to which lubrication circuit the leakage lubrication fluid collection means is connected.

13. A main bearing for a wind turbine, comprising an inner ring and an outer ring, wherein the main bearing is a slide bearing and the inner ring is adapted to be stationary while the outer ring is adapted to rotate around the inner ring, with the main bearing being lubricated with a lubrication fluid, and with the outer ring comprising a first sealing means and a second sealing means arranged at both sides of the outer ring for sealing to the inner ring and extending around the outer ring, wherein an associated stationary leakage lubrication fluid collection means is provided to be arranged adjacent to the first sealing means, which leakage lubrication fluid collecting means is adapted to collect lubrication fluid leaking from the first sealing means and the second sealing means, wherein the outer ring is provided with one or more axial bores connecting a leakage lubrication fluid collection area adjacent to the second sealing means to the leakage lubrication fluid collection means and wherein each sealing means comprises a groove accommodating a sealing element and a sealing element carrier ring having a fold and a clamp ring attached to the carrier ring closing the fold to build the groove and clamping the sealing means in the groove.

Description

BRIEF DESCRIPTION

[0023] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0024] FIG. 1 shows a principal perspective sketch of a wind turbine;

[0025] FIG. 2 shows a principle sketch of the arrangement of a hub, a rotor, and a main bearing according to an embodiment;

[0026] FIG. 3 shows an enlarged sectional view of the main bearing according to an embodiment;

[0027] FIG. 4 shows an enlarged perspective view of a main bearing side with a second sealing means according to an embodiment;

[0028] FIG. 5 shows an enlarged perspective view of the main bearing side with a first sealing means according to an embodiment; and

[0029] FIG. 6 shows a cross sectional view of the main bearing, in part, showing the fixation of the first and second sealing means to an outer ring according to an embodiment.

DETAILED DESCRIPTION

[0030] FIG. 1 shows an inventive wind turbine 1, comprising a rotor 2 rotatably arranged at a nacelle 3, which is arranged on the top of a tower 4. The rotor 2 comprises three rotor blades 5 attached to a hub 6 as is commonly known. The rotor blades 5 interact with the wind making the rotor rotate. The rotor drives an electric generator, for example, a direct drive generator.

[0031] FIG. 2 shows an arrangement with the central elements of the wind turbine 1. It shows the hub 6 which is connected to a direct drive generator 7 comprising a rotor 8, which here is directly coupled to the hub 6, and further a stator 9. The stator 9 is stationary fixed to a main shaft 10.

[0032] The arrangement of hub 6 and rotor 8 is rotatable relative to the stationary shaft 10 respectively the stator 9. For bearing the hub-rotor-arrangement a main bearing 11 is provided, which in the shown embodiment is a slide bearing 12 comprising an outer ring 13, to which the hub-rotor-arrangement with the hub 6 and the rotor 8 is connected, so that, when the hub 6 rotates, also the outer ring 13 and the rotor 8 rotate. The main bearing 11 further comprises an inner ring 14 which is stationary and which is fixed to the main shaft 10.

[0033] As the main bearing 11 is a slide bearing 12 the rotating outer ring 13 is slidingly guided by axial and radial guiding or sliding pads or alternatively by tapered guiding or sliding pads in a tapered sliding bearing. FIG. 2 shows front axial pads 15 and rear axial pads 16 for axially guiding the outer ring 13 and radial pads 17 for radially guiding the outer ring 13. The pads 15, 16 and 17 are stationary fixed to the stationary inner ring 14. A sliding pad (15, 16, 17) may comprise several components (not shown) e.g. an outer sliding part, a support part for attachment to a structure by bolts or similar, a tilting support part to ensure that the sliding pad is able to tilt and/or a resilient means like e.g. a spring to ensure a preloading of the sliding pad and the tilting support.

[0034] The axis of rotation of the rotor 2 and therefore also the axis of rotation of the main bearing 11 is slightly tilted relative to the horizontal plane or axis. FIG. 2 shows the tilt angle α, which the axis of rotation 18 of the main bearing 11 shows relative to the horizontal plane or axis 19. Therefore the main bearing 11 is slightly tilted, which is advantageous for a simple leakage lubrication fluid collection system, which will be explained in detail below.

[0035] As mentioned, the main bearing 11 is a slide bearing. This slide bearing needs to be lubricated by a lubrication fluid, which provides an extremely thin hydrodynamic fluid film between the sliding surfaces of the outer ring, which rotates, and the axial and radial pads 15, 16 and 17. It is therefore necessary to constantly provide enough lubrication fluid in this area, which can either be flooded or directly introduced respectively lubricated to respective bearing point or evacuated bearing cavities etc. The lubrication system needs to maintain a permanent and constant lubrication amount in this area.

[0036] For providing a constant lubrication, an automatic lubrication arrangement 20 is provided, which is shown in principle in FIG. 2. This lubrication arrangement comprises a reservoir 21 with the lubrication fluid 22, which is integrated in a lubrication circuit 23. The lubrication fluid 22 circulates in the circuit 23 with a pump 24 integrated in the circuit 23. The circuit 23 comprises one or more fluid pipes, which or at least some of which are guided to the main bearing 11 to emit the lubrication fluid 22 at one or several points to the main bearing 11 or to completely flood it. As FIG. 2 further shows, the lubrication arrangement 20 further comprises in the circuit 23 a redirection pipe which allows for redirecting any collected leakage lubrication fluid which leaks from the main bearing 11 and which is redirected in the circuit 23, which collection system is explained below.

[0037] FIG. 3 shows an enlarged partial view of the main bearing 11 respectively the slide bearing 12. The figure shows partly the outer ring 13 and the inner ring 14, and also the hub 6 which is in this embodiment attached to the outer ring 13. FIG. 3 shows a cross sectional view of the lower end of the main bearing 11.

[0038] The outer ring 13 is provided with a first sealing means 25 attached to the one respectively inner side of the outer ring 13 and with a second sealing means 26 attached to the other side of the outer ring 13. Each sealing means 25, 26 comprises a sealing element 27, 28, which slidingly contacts the adjacent stationary surface of the inner ring 14. Each sealing element 27, 28 may comprises lips slidingly contacting the inner ring surface, which lips respectively detailed setup is not shown in the figure.

[0039] Each sealing means 25, 26 further comprises a sealing element carrier 29, 30 having a fold 31, 32. Furthermore each sealing means 25, 26 comprises a clamp ring 33, 34 attached to the element carrier 29, 30, which closes the fold 31 for building a respective groove 35, 36, in which the sealing element 27, 28 is arranged respectively clamped.

[0040] Both sealing means 25, 26 provide a good and tight sealing, nevertheless some leakage of the lubrication fluid 22 may occur. As mentioned this leakage lubrication fluid is collected and redirected to the lubrication circuit 23.

[0041] For collecting the leakage fluid leaking from the second sealing means 26 a leakage lubrication fluid collection area 37, which is realised as a circular groove 38 is realised in the clamp ring 34. This groove 38 is as close as possible to the sealing element 32, so that any lubrication fluid leaking from this sealing element 32 is collected in the groove 38.

[0042] This leakage lubrication fluid collection area 37 is connected to a leakage lubrication fluid collection means 39 realised as a collector ring 40 extending around the main bearing. This lubrication collecting means 39 respectively the collector ring 40 is stationary attached for example, to the inner ring 14 in embodiments, so that it is close to the first sealing means 25.

[0043] The collector ring 40 comprises a collection groove 41, where any leaking lubrication fluid is collected, which collection groove 41 is connected to the lubrication circuit 23 for redirecting the collected leakage fluid.

[0044] For transferring leakage fluid collected in the groove 38 several axial bores 42 are provided, which connect the leakage lubrication fluid collection area 37 to the leakage lubrication fluid collection means 39, therefore it connects the groove 38 to the collector ring 40. A number of parallel axial bores 42 are provided and distributed equally around the circumference of the outer ring 13. Each axial bore 42 is open to the groove 38 at the one end and open to the collector ring 40 at the other end. It comprises several bore sections, as each axial bore 42 extends through the clamp ring 34, the sealing element carrier 30, the outer ring 13, the sealing element carrier 29 and the clamp ring 33 as FIG. 3 clearly shows. All respective bore sections are in alignment, so that a fluid channel is built.

[0045] As the main bearing 11 is slightly tilted towards the horizontal axis as shown by the axis of rotation 18 and the horizontal axis 19 and the tilt angle α in FIG. 3, and as therefore the right side of the main bearing with the first sealing means 25 is, due to the tilt, somehow lower than the other side with the second sealing means 26, each axial bore 42 is also slightly tilted with a tilt angle α towards the horizontal axis, so that a natural flow direction is realised and the lubrication fluid flows automatically from the groove 38 to the collector ring 40.

[0046] When exiting the respective axial bore 42 the lubrication fluid flows on a drip edge ring 43 fixed to the first sealing means 25, which drip edge ring 43 collects the fluid exiting the axial bore 42 and guides it to the collector ring 40. It axially extends into the collector ring 40 as FIG. 3 clearly shows.

[0047] Not only the lubrication fluid leaking the second sealing means 26 is collected on the drip edge ring 43 and the carrier ring 40, but also the lubrication fluid leaking from the first sealing means 25. This leakage fluid directly flows on the drip edge ring 43 and from there directly to the collector ring 40.

[0048] The respective leakage fluid flow is shown in FIG. 3 by the respective arrows.

[0049] The lubrication fluid is present in the inner of the main bearing 11, which is either flooded with the lubrication fluid respectively the oil, or the fluid is directly lubricated to certain points. The lubrication fluid is present in the areas 44, 45 of the main bearing 11, therefore on one side of each sealing means 25, 26, from where it leaks through the sealing means 25, 26 and is collected as explained above.

[0050] FIG. 4 shows in an enlarged perspective view the second sealing means 26 with the sealing element carrier 30 and the clamp ring 34 with the groove 38. Attached to the clamp ring 34 is a sealing element 46 in form of a sealing lip which extends to the inner ring 14. This sealing element 46 provides a sealing on this side, so that any leakage lubrication fluid collected in the groove 38 remains in the groove 38 until it flows in the respective bore 42.

[0051] For fixing the element carrier 30 tightly to the inner ring 13 and for fixing the clamp ring 34 tightly to the element carrier 30, respective further sealing elements 47, 48 are arranged in respective grooves 49, 50 for example provided in the sealing element carrier 30 and the clamp ring 34 for example. This allows for an axial sealing of this element connection.

[0052] An enlarged view of the other bearing side showing the first sealing means 25 is shown in FIG. 5. Also here respective sealing elements 51, 52 are arranged in respective grooves 53, 54, for example again provided in the surfaces of the sealing element carrier 29 and the clamp ring 33 in embodiments.

[0053] FIG. 5 shows furthermore the attachment of the collector ring 40 to the stationary inner ring 14 and the overlap of the drip edge ring 43 over or into the collector ring 40 respectively the collection groove 41, so that any leakage oil dripping from the drip edge of the drip edge ring 40 directly drips into this collection groove 41.

[0054] FIG. 6 shows a cross section view showing the fixation of the first and second sealing means 25, 26 to the outer ring 13. Each sealing element carrier 29, 30 is connected with first bolt connections 55, 56 to the outer ring 13. The outer ring 13 is provided with respective threaded bores, into which the bolt connections 55, 56, which are accommodated in respective through bores of the sealing element carrier 29, 30, are screwed.

[0055] The clamp rings 33, 34 and in addition, as a second fixation means, also the whole sealing means 25, 26 is fixed by respective further bolt connections 57, 58, which engage a respective through bore in the clamp ring 33, 34 and the sealing element carrier 29, 30 and extends into respective threaded bores in the outer ring, as shown in FIG. 6.

[0056] Although the present invention has been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0057] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.