WIND TURBINE ROTOR BLADE PITCH BEARING

Abstract

Provided is a wind turbine rotor blade pitch bearing for mounting a rotor blade to a hub, including a carrier with an annular arrangement of bearing pad seats; a plurality of bearing pads, wherein a bearing pad is arranged in each bearing pad seat of the carrier; and a gripping assembly for gripping the carrier, which gripping assembly including a sliding part arranged to lie against an annular arrangement of bearing pads and further includes an access window dimensioned to expose a bearing pad when opened. A wind turbine with a number of such pitch bearings; and a method of performing a service routine on a wind turbine rotor blade pitch bearing is further provided.

Claims

1. A pitch bearing for mounting a rotor blade to the hub of a wind turbine, comprising a carrier with an annular arrangement of bearing pad seats; a plurality of bearing pads, wherein a bearing pad is arranged in each bearing pad seat of the carrier; and a gripping assembly for gripping the carrier, which gripping assembly comprises a sliding part arranged to lie against an annular arrangement of bearing pads and further comprises an access window dimensioned to expose a bearing pad when opened.

2. The pitch bearing according to claim 1, wherein the carrier comprises a first face and an opposite second face, and an annular arrangement of bearing pad seats in each face, and wherein the pitch bearing comprises a first set of bearing pads arranged in the bearing pad seats of the first carrier face and a second set of bearing pads arranged in the bearing pad seats of the second carrier face.

3. The pitch bearing according to claim 1, wherein the gripping assembly comprises a first sliding part arranged to lie against the bearing pads of the first carrier face and a second sliding part arranged to lie against the bearing pads of the second carrier face.

4. The pitch bearing according to claim 3, wherein the gripping assembly comprises a distance ring arranged between the first sliding part and the second sliding part, and wherein the sliding parts and the distance ring are realized as a single entity.

5. The pitch bearing according to claim 3, comprising a single access window in each sliding part.

6. The pitch bearing according to claim 1, wherein an access window is shaped to fit in an opening formed in a sliding part.

7. The pitch bearing according to claim 6, wherein the opening has tapered side walls.

8. The pitch bearing according to claim 1, wherein the bearing pads are realized as polymer bearing pads.

9. The pitch bearing according to claim 1, wherein the carrier is realized as a stationary component of the pitch bearing and is mounted to the hub.

10. The pitch bearing according to claim 1, wherein the carrier is realized as a rotatory component of the pitch bearing and is mounted over the root end of the rotor blade.

11. A wind turbine comprising a number of rotor blades, wherein each rotor blade is mounted to the hub by a pitch bearing according to claim 1, and a pitch system for turning each rotor blade about its longitudinal axis.

12. The wind turbine according to claim 11, wherein the pitch system comprises a pitch drive unit for each rotor blade, wherein a pitch drive unit comprises a pinion arranged to engage with a toothed ring arranged about a circumference of the rotor blade.

13. A method of performing a service routine on the wind turbine rotor blade pitch bearing according to claim 1, which method comprises steps of opening an access window of a sliding part; actuating the pitch system to turn the sliding part relative to the carrier until a bearing pad appears in the opened access window; at least one of inspecting and replacing the bearing pad; and closing the access window.

14. The method according to claim 13, wherein a bearing pad on the first face of the carrier and a bearing pad on the second face of the carrier are at least one of inspected and replaced at one position of the pitch system.

Description

BRIEF DESCRIPTION

[0025] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0026] FIG. 1 shows a plan view of an embodiment of the inventive rotor blade pitch bearing;

[0027] FIG. 2 shows a cross-section through the embodiment of FIG. 1;

[0028] FIG. 3 shows a plan view of a further embodiment of the inventive rotor blade pitch bearing;

[0029] FIG. 4 shows a cross-section through the embodiment of FIG. 3;

[0030] FIG. 5 shows the pitch system has been actuated to move the sliding parts relative to the carrier to align a pad P with an access window;

[0031] FIG. 6 shows the access window has been opened, and the pad P is removed from its seat in the carrier; and

[0032] FIG. 7 illustrates exemplary stages in an embodiment of the inventive method.

DETAILED DESCRIPTION

[0033] FIG. 1 shows a plan view of an embodiment of the inventive rotor blade pitch bearing 1. Here, the viewer is looking in the direction of the hub from a vantage point in the interior of a rotor blade 2. FIG. 2 shows cross-section II-II. A first sliding ring 11A is mounted to the root end 20 of the rotor blade 2, and a spacer or distance ring 11D is placed between the first sliding ring 11A and a second sliding ring 11B. The root end 20, sliding rings 11A, 11B and spacer 11D are connected and act as a single entity.

[0034] A disc-shaped pad carrier 10A is mounted to the hub 3. A pitch drive 17 is mounted to the carrier 10 and engages with an annular toothed ring at the inner edge of the first sliding ring 11A to turn the rotor blade 2 about its longitudinal axis L.

[0035] FIG. 1 indicates an annular arrangement of bearing pads P set into recesses or seats 10S in the pad carrier 10, and FIG. 2 shows the seats 10S on both faces 101, 102 of the carrier 10. The diagrams also indicate an access window 11W in the first sliding ring 11A and an access window 11W in the second sliding ring 11B. Here, each bearing pad P is arc-shaped, while the access window 11W is essentially rectangular for ease of manufacture. While the diagram only shows a small number of bearing pads for the sake of clarity, it shall be understood that the pitch bearing with a diameter of several meters may avail of many bearing pads, for example 40-60 or more. These may be arranged very close together, unlike the wide spacing shown here.

[0036] For the purposes of illustration in FIG. 2, the access windows 11W, 11W are shown to be diametrically opposite, but this is not necessary. Instead, it is advantageous if both access windows 11W are positioned to simultaneously expose an entire bearing pad P.

[0037] FIG. 2 shows that an access window opening has tapered or slanting side faces, and corresponding slanted edges along the sides of the access window 11W, so that the access window 11W cannot protrude into the interior of the bearing 1.

[0038] FIG. 3 shows a plan view of a further embodiment of the inventive rotor blade pitch bearing 1, and FIG. 4 shows a cross-section IV-IV. Here also, the viewer is looking in the direction of the hub 3 from a vantage point in the interior of a rotor blade 2. In this embodiment, an annular pad carrier 10 is mounted to the root end 20 of the rotor blade 2. The sliding parts 11A, 11B in this embodiment are mounted to the hub 3, again with a spacer or distance ring 11D between. Here, an inner sliding part 11B is disc-shaped and closes off the hub 3. The outer sliding part 11A is annular and extends about the root end 20 of the rotor blade 2. A pitch drive 17 is mounted to the inner sliding part 11A and engages with a toothed ring at the inner edge of the annular pad carrier 10. In this case also, an annular arrangement of bearing pads P is set into recesses or seats 10S on either side 101, 102 of the pad carrier 10, and each sliding part 11A, 11B has an access window 11W to expose an entire bearing pad P.

[0039] FIGS. 5-8 illustrate stages in an exemplary service routine. In FIG. 5, the pitch system has been actuated to move the sliding parts 11A, 11B relative to the carrier 10 to align a pad P with an access window 11W. In FIG. 6, the access window 11W has been opened, and the pad P is removed from its seat 10S in the carrier 10. In FIG. 7, a replacement pad P is inserted through the access opening 11W and the access window can be closed again. Of course, before closing the access window 11W, the pitch system can be actuated to align the next pad P with the access window 11W, and the steps can be repeated as often as necessary to inspect and/or replace the desired number of pads P.

[0040] 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 invention. For example, the pitch bearing may be realized in any suitable manner in addition to the embodiments described above: the pad carrier may be mounted to the rotor blade root end or to the hub; the gripping assembly may extend about an outer circumference of a disc-shaped pad carrier or about an inner circumference of an annular pad-carrier; a pitch drive unit may be mounted inside or outside a rotor blade; etc.

[0041] 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.