PITCH BEARING ARRANGEMENT

Abstract

Provided is a pitch bearing arrangement of a wind turbine, including an outer bearing ring and an inner bearing ring arranged coaxially to each other and including a common symmetry axis, and at least one reinforcement plate arranged at the inner ring and at least one plate-like or beam-like stiffening means coupled to the outer ring axially adjacent to the at least one reinforcement plates and adapted to be coupled to a positioning means to be arranged at the other side of the at least one reinforcement plate used for pivoting the outer ring relative to the inner ring, with the at least one reinforcement plate including at least one hole through which the stiffening means is mechanically connectable or connected to the positioning means.

Claims

1. A pitch bearing arrangement of a wind turbine, comprising: an outer bearing ring and an inner bearing ring arranged coaxially to each other and comprising a common symmetry axis; at least one reinforcement plate arranged at the inner ring; and at least one plate-like or beam-like stiffening means coupled to the outer ring axially adjacent to the at least one reinforcement plate and adapted to be coupled to a positioning means to be arranged at an other side of the at least one reinforcement plate used for pivoting the outer ring relative to the inner ring, with the at least one reinforcement plate comprising at least one hole through which the stiffening means is mechanically connectable or connected to the positioning means.

2. The pitch bearing arrangement according to claim 1, wherein two or more reinforcement plates are provided, with the stiffening means being provided adjacent to one of the reinforcement plates and the positioning means being provided adjacent to another of the reinforcement plates, with the reinforcement plates comprising axially corresponding holes through which the stiffening means is mechanically connectable or connected to the positioning means.

3. The pitch bearing arrangement according to claim 1, wherein a mechanic connection means for connecting the stiffening means to the positioning means is provided.

4. The pitch bearing arrangement according to claim 3, wherein the mechanic connection means is accommodated in the hole or the holes.

5. The pitch bearing arrangement according to claim 4, wherein the hole or the corresponding holes are arranged eccentrical to the common axis.

6. The pitch bearing arrangement according to claim 5, wherein the one or the more reinforcement plates comprise two or more pairs of holes arranged equally or unequally distributed around the common axis for accommodating two connection means.

7. The pitch bearing arrangement according to claim 5, wherein the or each hole is kidney-shaped, circular, oval, triangular, rectangular or of any other multisided shape.

8. The pitch bearing arrangement according claim 4, wherein both reinforcement plates are ring-shaped and comprise axially corresponding center holes for accommodating the connection means.

9. The pitch bearing arrangement according to claim 8, wherein the connection means is arranged eccentrical to the common axis, or that a centric carrier with a gear ring connected or connectable to the positioning means is provided.

10. The pitch bearing according to claim 9, wherein two connection means are arranged eccentrical and equally or unequally distributed around the common axis.

11. The pitch bearing arrangement according to claim 2, wherein the reinforcement plates are parallel or angled to each other, with the stiffening means being parallel to the adjacent reinforcement plate.

12. The pitch bearing arrangement according to claim 1, wherein the one or the more reinforcement plates are ring-shaped and that the or each reinforcement plate comprises at least one center hole for accommodating a section of the stiffening means extending into or through the hole or the holes.

13. The pitch bearing arrangement according to claim 12, wherein the section at least in part has a single or a double wall structure.

14. The pitch bearing arrangement according to claim 12, wherein the reinforcement plate adjacent to the stiffening means has a cone form and that the stiffening means has a corresponding form, or that the reinforcement plate adjacent to the stiffening means has a flat form and the stiffening means has a trough-like form.

15. A wind turbine, comprising a hub, at least one rotor blade and at least on pitch bearing arrangement according to claim 1, wherein the pitch bearing arrangement pivotably connects the rotor blade to the hub.

16. The wind turbine according to claim 14, wherein the rotor blade is attached to the outer ring and the hub to the inner ring, and that the positioning means is or are arranged inside the hub.

Description

BRIEF DESCRIPTION

[0027] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0028] FIG. 1 shows a wind turbine with pitch regulated wind turbine rotor blades;

[0029] FIG. 2 show a perspective view of a pitch bearing arrangement according to a first embodiment;

[0030] FIG. 3 shows a perspective cut view of the arrangement of FIG. 2;

[0031] FIG. 4 shows a cut view of a pitch bearing arrangement of a second embodiment;

[0032] FIG. 5 shows a perspective cut view of the second embodiment; and

[0033] FIG. 6 shows a cut view of a third embodiment of an inventive pitch bearing arrangement.

DETAILED DESCRIPTION

[0034] In FIG. 1 a wind turbine 1 is shown. The wind turbine 1 comprises a nacelle 2 and a tower 3. The nacelle 2 is mounted at the top of the tower 3. The nacelle 2 is mounted rotatable with regard to the tower 3 by means of a jaw bearing. The axis of rotation of a nacelle 2 with regard to the tower 3 is referred to as the jaw axis.

[0035] The wind turbine 1 furthermore comprises a hub 4 with one or more rotor blades 5, three rotor blades 5. The hub 4 is mounted rotatable relative to the nacelle 2 by means of a main bearing. The hub 4 is mounted rotatable about a rotor axis of rotation 6.

[0036] The wind turbine 1 furthermore comprises a main shaft connecting the hub 4 with a rotor of a generator 7. If the hub 4 is connected directly to the rotor, the wind turbine is referred to as a gearless, direct drive wind turbine. Alternatively, the hub 4 may also be connected to the rotor via a gear box. This type of wind turbine is commonly referred to as a geared wind turbine.

[0037] The generator 7 is accommodated within the nacelle 2. It comprises a rotor and a stator and, as known, converts the rotational energy from the rotor into electrical energy.

[0038] In the example shown in FIG. 1 the wind turbine 1 comprisesthree rotor blades 5, two of which are shown in FIG. 1. The rotor blades 5 are mounted rotatable with regard to the hub 4 by means of respective pitch bearing arrangements 8. The rotor blades 5 may thus be pitched in order to optimize their orientation with regard to the wind flow impinging on the wind turbine 1.

[0039] Each rotor blade 5 comprises a root section 9 and a tip section 10. The root section refers to the part of the rotor blade 5 which is closest to the hub 4 and pitch bearing arrangement 8. The common set up of such a wind turbine with pitchable blades is known.

[0040] FIG. 2 shows a first embodiment of an inventive pitch bearing arrangement 8. It comprises, see also FIG. 3, an outer bearing ring 11 and an inner bearing ring 12 with bearing elements, for example tapered rollers or balls, being arranged between the rings 11, 12. The inner ring 12 is connected to the hub 4, while the outer ring 11 is connected to a root element 13 which is part of the blade 5.

[0041] The pitch bearing arrangement 8 further comprises two reinforcement plates 14, 15 which are attached to the upper and lower end of the inner ring 11. The reinforcement plates 14, 15 are flat plates closing the inner of the inner bearing ring 12, see FIG. 2. Each reinforcement plate 14, 15 comprises two eccentrical arranged kidney-shaped holes 17, 18, which are axially aligned with each other forming two axially corresponding hole pairs as clearly shown in FIGS. 2, 3. As shown in the figures, the reinforcement plates 14, 15 may be realized by two plate halves, which are connected to each other in the middle, see the respective seams 19, 20. Each plate half comprises a respective hole 17, 18.

[0042] The inventive pitch bearing arrangement 8 further comprises a stiffening element 21 here in form of a flat beam, which is adjacent and parallel to the outer reinforcement plate 14 and in relative close distance to the plate 14. This stiffening means 21 is attached to the outer ring 11.

[0043] As FIG. 3 shows a positioning means 22 here comprising a pitch cylinder 23 is arranged within the hub 4. By means of a fixation element 24 it is attached to inner circumference of the hub 4 close to the lower reinforcement plate 15. The piston 25 which can be pushed out of the pitch cylinder 23 is connected to a mechanical connection means 26 via a pivot connection 27. The other end of this mechanical connection means 26 is firmly attached to the bottom side of the stiffening means 21, i.e. the flat elongated beam and extends through the corresponding holes 17, 18. In FIG. 3 only one positioning means 22 and one mechanical connection means 26 are shown. It is to be noted, that there is certainly a second positioning means 22 and a second mechanical connection means 26 arranged at the opposite side of the hub respectively in the other pair of eccentric holes 17, 18. Both mechanical connection means 26 are shown in FIG. 2.

[0044] The positioning means 22 are adapted to pivot the outer ring 11 relative to the inner ring 12 and thus to pitch the blade 5 relative to the hub. When the pistons 25 of both positioning means 22 are pushed out of the cylinder housing this linear movement is transferred to the connection means 26. Due to the pivot connection 27 the connection means 26 rotates relative to the positioning means and moves in the holes 17, 18 allowing the outer ring 11 to be rotated. Thus, simply by pushing the pistons 25 out or retracting them in the cylinder housing the outer ring 11 and thus the blade 5 can be pitched relative to the hub 4.

[0045] As it is obvious from FIG. 3 the positioning means and the connection means 26 are arranged in the hub and thus are accessible through the hub for maintenance purpose. There is in principle no need for the maintenance personal to enter the blade, as no relevant mechanical component is arranged in the blade but only in the hub.

[0046] FIGS. 4 and 5 show a second embodiment of an inventive pitch bearing arrangement 8. Again, the hub 4 and a root element 13 are shown which are connected to each other via the pitch bearing arrangement 8 comprising the outer ring 11 attached to the root element 13 and the inner ring 12 attached to the hub 4. The inner ring 12 again is reinforced by two reinforcement plates 14, 15. Both reinforcement plates 14, 15 are designed as ring plates comprising two center holes 17, 18. While the lower reinforcement plate 15 is a flat ring plate, the upper reinforcement plate 14 is a cone-shaped ring plate which is connected with its inner circumference to the inner circumference of the lower reinforcement plate 15 as shown in FIGS. 4 and 5.

[0047] Also, in this embodiment a stiffening means 21 is coupled to the outer ring 11. The stiffening means 21 has a bent form corresponding to the form of the cone-shaped upper reinforcement plate 14, see especially FIG. 5. Its center section 28 is in this embodiment double-layered and extends into the two plate holes 17, 18, so that the bottom 29 of this center section 28 corresponds to the plane in which the lower hole 18 is situated or extends even below this plane.

[0048] A mechanical connection means 26 is eccentrically attached to the bottom side 29 of the center section 28, to which connection means 26 the positioning means 22 respectively the pitch cylinder 23 is attached with its piston 25, while the cylinder housing is attached to the hub 4 by means of a fixation element 24. As the cut view of FIG. 5 shows, also in this embodiment two positioning means 22 and two respective eccentrical connection means 26 are provided, so that also in this embodiment the rotation of the outer ring 11 relative to the non-rotating inner ring 12 and thus the pitch of the blade 5 relative to the hub 4 can be realized by symmetrical rotation force.

[0049] Finally, FIG. 6 shows a third embodiment of an inventive pitch bearing arrangement 8 comprising an outer ring 11, an inner ring 12 attached to the blade route element 13 respectively the hub 4. The inner ring 11 is reinforced by means of reinforcement plates 14, 15, which are parallel to each other and comprise two respective center holes 17, 18 which are axially aligned.

[0050] The pitch bearing arrangement 8 further comprises a stiffening means 21 here in form of a trough-like or pot-like shaped plate which is attached to or coupled to the outer ring 11. The stiffening means 21 comprises a trough-like or pot-like center section 28 extending through both holes 17, 18. To the bottom side 29 of this trough-like or pot-like center section 28 the mechanical connection means 26 is attached, to which via a pivot connection 27 the piston of the positioning means 22, also here in form of a pitch cylinder 23 is attached. The other end of the positioning means 22 is again attached to the hub 4 via a not shown fixation element 24.

[0051] The position at the bottom side 29, to which the mechanical connection means 26 is attached, is eccentrical to the center axis to assure that the longitudinal movement of the piston is transferred to a rotational movement of the stiffening means 21 and thus the outer ring 11.

[0052] It is to be noted, that also in this embodiment a second positioning means 22 and a second mechanical connection means 26 is provided, which are arranged at a 180 position, thus also being attached eccentrical to the bottom side 29 for having a symmetrical force transfer on the stiffening means 21.

[0053] While the embodiments show two reinforcement plates, it is also possible to provide only one reinforcement plate and to connect the stiffening means through this one plate via a hole to the positioning means provided at the other plate side, with any of the connections being usable as shown in the pictures.

[0054] Although the present invention has been disclosed in the form of preferred 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 intention.

[0055] 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. The mention of a unit or a module does not preclude the use of more than one unit or module.