Method for optimizing the load on a main bearing of a wind turbine

Abstract

The invention relates to a method for optimizing the load on a main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a hydrodynamic plain bearing, in which at least one of the bearing rings (2, 3) consists of a number of bearing segments (4) which adjoin one another over the circumference of the bearing ring (2, 3), wherein each bearing segment (4) can be positioned in a defined radial position (r), and wherein each bearing segment (4) is arranged on a surrounding component (5). In order to provide optimized operation of the bearing, the invention makes provision for the method to comprise the steps of: a) carrying out a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3), in which the load on the bearing segment (4) when the latter is arranged on or in the surrounding component (5) is calculated when the anticipated bearing load is applied and when the bearing segment (4) is in a predetermined initial radial position (ro) relative to the surrounding component (5); b) carrying out a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3), in which the load on the bearing segment (4) when the latter is arranged on or in the surrounding component (5) is calculated when the anticipated bearing load is applied and when the bearing segment (4) is in a predetermined changed radial position (r1) relative to the surrounding component (5); c) comparing the loads, determined according to steps a) and b), on the bearing segments (4) and selecting the radial positions for all of the bearing segments (4), at which the most uniform possible load on all of the bearing segments (4) should be anticipated; d) adjusting the radial position of all of the bearing segments (4) according to step c).

Description

[0001] Method for optimizing the load on a main bearing of a wind turbine

[0002] Description

[0003] Field of the invention

[0004] The invention relates to a method for optimising the load on a main bearing of a wind turbine, wherein the main bearing is designed as a hydrodynamic plain bearing, in which at least one of the bearing rings consists of a number of bearing segments which are directly or indirectly connected to one another over the circumference of the bearing ring (further components can also be arranged between two segments if necessary), wherein each bearing segment can be positioned in a defined radial position and wherein each bearing segment is arranged on a surrounding component.

[0005] In addition to the traditional main bearing support for a wind turbine rotor using a rolling bearing, the use of a hydrodynamic plain bearing is also an option. Such bearings are a beneficial alternative to rolling bearings because they allow bearing replacement on the wind turbine tower without disassembling the rotor. Such a bearing can preferably have circumferentially segmented bearing rings. This has the advantage, especially for very large wind turbines, that very large forging and hardening facilities are not required to manufacture the bearing parts, and the transport of the bearing segments is much easier.

[0006] The individual bearing segments of the bearing ring must then be adjusted to their correct radial position during assembly to ensure proper bearing function. The problem that has emerged is that the surrounding component, in particular the bearing housing, can have varying degrees of stiffness (measured in the radial direction) around the circumference of the bearing ring, resulting in different loads being applied to the individual bearing segments.

[0007] Summary of the invention

[0008] The invention is therefore based on the object of proposing a method of the type mentioned above for a segmented hydrodynamic plain bearing as the main bearing for a wind turbine, with which it is possible to achieve optimized operation of the bearing.

[0009] The solution to this problem by the invention provides that the method comprises the steps: a) carrying out a numerical simulation for each of the bearing segments of the bearing ring or a numerical simulation which takes all bearing segments (4) into account, in which the load on the bearing segment is calculated when arranged on or in the surrounding component when subjected to the expected bearing load and with a predetermined initial radial positioning of the bearing segment relative to the surrounding component; b) carrying out a numerical simulation for each of the bearing segments of the bearing ring, in which the load on the bearing segment is calculated when arranged on or in the surrounding component when subjected to the expected bearing load and with a predetermined changed radial positioning of the bearing segment relative to the surrounding component;c) Comparison of the loads on the bearing segments determined in steps a) and b) and selection of the radial positioning for all bearing segments that is expected to result in the most uniform loading of all bearing segments; d) Adjustment of the radial positioning of all bearing segments in accordance with step c).

[0010] Although this procedure can already achieve a homogenization of the load on the individual bearing segments, a preferred embodiment of the proposed method provides that after step b) above and before step c) above, the following step is carried out: b') Repeated execution of the numerical simulation for each of the bearing segments of the bearing ring according to step b) above, wherein again changed radial positioning of the bearing segments is specified;

[0011] In step c) above, it is then intended that all determined loads on the bearing segments are taken into account in the comparison and selection.

[0012] The numerical simulation mentioned is preferably a finite element analysis (FEA).

[0013] During adjustment according to step d) above, the individual bearing segments are preferably each positioned radially with at least one adjusting element.

[0014] The process is preferably carried out on a hydrodynamic plain bearing whose outer ring has at least 6 bearing segments.

[0015] Furthermore, it is preferably provided that the method is only performed for the bearing segments of the bearing outer ring. When hydrodynamic plain bearings are used as main bearings in wind turbines, it is known that local load increases can occur in the area of ​​relatively stiff points of the housing (i.e., the surrounding component). This places a correspondingly higher load on the bearing, which is disadvantageous.

[0016] Although adjustment elements are known for geometrically adjusting the position of the individual bearing segments, i.e., for their radial positioning or height adjustment, they currently only adjust the geometric target value of the bearing segment, i.e., only a geometric adjustment of the bearing segments takes place.

[0017] The method according to the invention is used to advantageously reduce locally higher loads on bearing segments and thus increase the service life of the bearing. This allows, in particular, a longer service life to be achieved and thus the time required for replacing bearing segments to be extended. Ideally, all bearing segments are loaded evenly, which leads to a maximum service life of the main bearing.

[0018] The proposed method is based on the idea that the ambient stiffness of the housing and the expected bearing load are taken into account and all bearing segments are radially adjusted so that they are loaded as evenly as possible.

[0019] Using Finite Element Analysis (FEA), which is the preferred method, the stiffness of the surrounding structure can be calculated in a conventional manner. The radial adjustment of the individual bearing segments, i.e., the height adjustment, can then be varied, and the resulting loads on the individual bearing segments can be determined.

[0020] This allows the optimal radial adjustment for each bearing segment to be calculated iteratively or by applying conventional optimization algorithms, and then adjusted. The goal is to ensure that all bearing segments are loaded as evenly as possible. The result of the calculation is the respective default values ​​for the specific height adjustment of each bearing segment. These determined adjustment values ​​are then used as a basis for bearing assembly.

[0021] Short description of the drawings

[0022] The drawings illustrate an embodiment of the invention. They show:

[0023] Figure 1 schematically shows a main bearing of a wind turbine, which is accommodated in a bearing housing, and

[0024] Figure 2 shows detail “A” according to Figure 1 with some details on the radial adjustment of a bearing segment.

[0025] Detailed description of the drawings

[0026] Figure 1 shows the main bearing 1 of a wind turbine, which has an inner bearing ring 2 and an outer bearing ring 3. Both bearing rings 2, 3 are segmented, meaning each bearing segment 4 (see Figure 2) extends only over a portion of the circumference of the bearing ring; together, all bearing segments 4 then form the respective bearing ring. The main bearing 1 is arranged in a bearing housing 5, which is an adjacent component of the bearing.

[0027] In the illustrated embodiment, both the bearing inner ring 2 and the bearing outer ring 3 each have 18 segments that adjoin one another in the circumferential direction. From the sketch shown in Figure 1, the shape of the bearing housing 5 shows that, with respect to the radial direction r, the bearing housing 5 provides different rigidities for the individual bearing segments.

[0028] Figure 2 shows that the bearing segments 4 can be adjusted in the radial direction r (height adjustment), for which purpose adjusting elements 6 are used. These are, for example, a screw construction with which the bearing segment 4 can be fixed in a predetermined radial position relative to the bearing housing 5. The adjustment possibility of the bearing segment 4 using the adjusting elements 6 is indicated by arrows on the adjusting elements 6.

[0029] The aim of the procedure described above for adjusting the individual bearing segments 4 is to position all bearing segments radially in such a way that, for a given bearing load, all bearing segments are loaded as evenly as possible.

[0030] Accordingly, a finite element analysis (FEA) is first used to calculate the load that the individual bearing segments must bear for an initial radial positioning ro, taking into account the local stiffness of the bearing housing 5 and the expected bearing load. Initially, assuming the same initial radial positioning for all bearing segments 4, this will generally result in those bearing segments located at stiff points on the bearing housing being subjected to a higher load than those bearing elements located at less stiff points.

[0031] The FEA can now be repeated with modified radial positioning, as indicated in Figure 2 by the positionings n, r2, and rs. This results in modified values ​​for the load on the individual bearing segments 4.

[0032] By varying the values ​​for the radial positioning, optimized values ​​for the individual radial positioning of the individual bearing segments 4 can now be determined. Known optimization algorithms can be used for this purpose. In principle, however, the method can also be implemented in a basic manner by using a lower radial positioning for those bearing segments 4 that must bear a higher load than the average across all bearing segments and / or by using a higher radial positioning for those bearing segments 4 that must bear a lower load than the average across all bearing segments.

[0033] In this way, the load on all bearing segments can be adjusted iteratively by determining the respective radial positioning, which, after the aforementioned calculation has been carried out, is then used as a basis for assembling the main bearing.

[0034] List of reference symbols

[0035] 1 main bearing

[0036] 2 bearing ring (bearing inner ring)

[0037] 3 Bearing ring (bearing outer ring)

[0038] 4 bearing segment

[0039] 5 Surrounding component (bearing housing)

[0040] 6 Actuator r radial position of the bearing segment ro initial radial positioning n changed radial positioning r2 further changed radial positioning rs further changed radial positioning

Claims

Patent claims 1. A method for optimizing the load on a main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a hydrodynamic plain bearing, in which at least one of the bearing rings (2, 3) consists of a number of bearing segments (4) which are directly or indirectly connected to one another over the circumference of the bearing ring (2, 3), wherein each bearing segment (4) can be positioned in a defined radial position (r) and wherein each bearing segment (4) is arranged on a surrounding component (5), characterized in that the method comprises the steps of: a) carrying out a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3) or a numerical simulation which takes all bearing segments (4) into account,in which the load on the bearing segment (4) is calculated when arranged on or in the surrounding component (5) when subjected to the expected bearing load and with a predetermined initial radial positioning (ro) of the bearing segment (4) relative to the surrounding component (5); b) carrying out a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3), in which the load on the bearing segment (4) is calculated when arranged on or in the surrounding component (5) when subjected to the expected bearing load and with a predetermined changed radial positioning (n) of the bearing segment (4) relative to the surrounding component (5);, c) Comparison of the loads on the bearing segments (4) determined in steps a) and b) and selection of the radial positioning for all bearing segments (4) at which the most uniform loading of all bearing segments (4) is to be expected; d) Adjustment of the radial positioning of all bearing segments (4) in accordance with step c).

2. Method according to claim 1, characterized in that after step b) and before step c) of claim 1 the step is carried out: b') Repeated execution of the numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3) according to step b) according to claim 1, wherein again changed radial positionings (r2, rs, ...) of the bearing segments (4) are specified, wherein in step c) according to claim 1 all determined loads of the bearing segments (4) are then taken into account in the comparison and in the selection.

3. Method according to claim 1 or 2, characterized in that the numerical simulation is a finite element analysis (FEM).

4. Method according to one of claims 1 to 3, characterized in that the bearing segment (4) is radially positioned with at least one adjusting element (6) during the adjustment according to step d) of claim 1.

5. Method according to one of claims 1 to 4, characterized in that it is carried out for a hydrodynamic plain bearing whose outer ring (3) has at least 6 bearing segments.

6. Method according to one of claims 1 to 5, characterized in that it is carried out only for the bearing segments (4) of the bearing outer ring (3).

Images