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

Abstract

Method for optimizing the load of a main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a hydrodynamic sliding bearing, in which at least one of the bearing rings (2, 3) consists of a number of bearing segments (4) which connect directly or indirectly 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 an surrounding component (5), characterized in that the method comprises the steps: a) Performing a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3) or a numerical simulation that considers all bearing segments (4), in which the load on the bearing segment (4) when arranged on or in the surrounding component (5) is calculated when subjected to the expected bearing load and at a given initial radial positioning (r0) of the bearing segment (4) relative to the surrounding component (5); b) Performing 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 arranged on or in the surrounding component (5) is calculated when subjected to the expected bearing load and with a given changed radial positioning (r1) of the bearing segment (4) relative to the surrounding component (5); c) Comparison of the loads on the bearing segments (4) determined according to steps a) and b) and selection of the radial positions for all bearing segments (4) where a load on all bearing segments (4) can be expected to be as uniform as possible; d) Adjustment of the radial positioning of all bearing segments (4) according to step c).

Description

Field of invention

[0001] The invention relates to a method for optimizing the load of a main bearing of a wind turbine, wherein the main bearing is designed as a hydrodynamic sliding bearing, in which at least one of the bearing rings consists of a number of bearing segments which connect directly or indirectly to each other around the circumference of the bearing ring (additional components may optionally be arranged between two segments), wherein each bearing segment can be positioned in a defined radial position and wherein each bearing segment is arranged on an surrounding component.

[0002] In addition to the conventional main bearing arrangement for the rotor of a wind turbine using a rolling bearing, the use of a hydrodynamic plain bearing, as disclosed in DE 10 2013 211 710 B3 or AT 524 520 B1, is also a viable option. Such bearings are an advantageous alternative to rolling bearings because bearing replacement on the wind turbine tower is possible without disassembling the rotor. Preferably, such a bearing can have circumferentially segmented bearing rings. This is particularly advantageous for very large wind turbines because large forging and hardening facilities are not required for manufacturing the bearing components, and the transport of the bearing segments is significantly simplified.

[0003] The individual bearing segments of the bearing ring must then be adjusted to their correct radial position during the assembly of the bearing in order to ensure the functionality of the bearing.

[0004] The problem that arose was that the surrounding component, i.e., in particular the bearing housing, can have different stiffness (measured in the radial direction) around the circumference of the bearing ring, which results in the individual bearing segments being subjected to different loads. Summary of the invention

[0005] The invention is therefore based on the objective of proposing a method of the type mentioned above for a segmented hydrodynamic sliding bearing as a main bearing for a wind turbine, with which it is possible to achieve optimized operation of the bearing.

[0006] The invention provides that the method has the following steps to solve this problem: a) Performing a numerical simulation for each of the bearing segments of the bearing ring or a numerical simulation that considers all bearing segments (4) in which the load on the bearing segment when arranged on or in the surrounding component is calculated when subjected to the expected bearing load and with a given initial radial positioning of the bearing segment relative to the surrounding component; b) Performing a numerical simulation for each of the bearing segments of the bearing ring, in which the load on the bearing segment is calculated when it is arranged on or in the surrounding component under the expected bearing load and with a given changed radial positioning of the bearing segment relative to the surrounding component; c) Comparison of the loads on the bearing segments determined according to steps a) and b) and selection of the radial positions for all bearing segments where the most uniform load on all bearing segments can be expected; d) Adjustment of the radial positioning of all bearing segments according to step c).

[0007] Although this approach can already achieve a more even distribution of the load across the individual bearing segments, a preferred embodiment of the proposed method provides that the following step is carried out after step b) above and before step c) above: b') Repeated execution of the numerical simulation for each of the bearing segments of the bearing ring according to step b) above, again specifying changed radial positions of the bearing segments;

[0008] In step c) above, it is stipulated that all determined loads on the bearing segments are taken into account during the comparison and selection process.

[0009] The numerical simulation mentioned is preferably a finite element analysis (FEA).

[0010] When adjusting according to step d) above, the individual bearing segments are preferably positioned radially with at least one adjusting element.

[0011] The method is preferably carried out on a hydrodynamic sliding bearing whose outer ring has at least 6 bearing segments.

[0012] Furthermore, it is preferably provided that the procedure is only carried out for the bearing segments of the outer bearing ring.

[0013] When hydrodynamic plain bearings are used as main bearings in wind turbines, it is known that local load increases can occur in areas of relatively stiff parts of the housing (i.e., the surrounding component). This results in a correspondingly higher load on the bearing, which is disadvantageous.

[0014] While adjusting elements are known for the geometric alignment of the position of individual bearing segments, i.e., their radial positioning or height adjustment, these currently only set the geometric target value of the bearing segment; that is, only a geometric alignment of the bearing segments is performed.

[0015] To advantageously reduce locally higher loads on bearing segments and thus increase the service life of the bearing, the method according to the invention is used. This allows, in particular, a longer service life to be achieved and thus extends the intervals for replacing bearing segments. Ideally, all bearing segments are loaded uniformly, resulting in maximum service life for the main bearing.

[0016] 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 positioned so that they are loaded as evenly as possible.

[0017] Using the preferred finite element analysis (FEA), the stiffness of the surrounding structure can be calculated in a known manner. The radial adjustment of the individual bearing segments, i.e., the height setting, can then be varied, and the resulting loads on each bearing segment can be determined.

[0018] Thus, the optimal radial adjustment for each bearing segment can be calculated iteratively or by using known optimization algorithms, and then set accordingly. The goal is to ensure that all bearing segments are loaded as evenly as possible. The result of the calculation is therefore a setpoint for the specific height adjustment of each bearing segment. These determined settings are then used as the basis for bearing assembly. Brief description of the drawings

[0019] The drawings illustrate an embodiment of the invention. They show: Fig. 1 schematically a main bearing of a wind turbine, which is housed in a bearing casing, and Fig. 2 the detail “A” according to Fig. 1 with details regarding the radial adjustment of a bearing segment. Detailed description of the drawings

[0020] In Fig. 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, i.e., each bearing segment 4 (see figure 1) is divided into two parts. Fig. 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 a component surrounding the bearing.

[0021] In the illustrated embodiment, both the inner bearing ring 2 and the outer bearing ring 3 each have 18 segments that connect to each other in the circumferential direction.

[0022] From the in Fig. As can be seen from the shape of the bearing housing 5 in the sketch shown in Figure 1, different stiffnesses are given for the individual bearing segments with respect to the radial direction r through the bearing housing 5.

[0023] In Fig. Figure 2 shows that the bearing segments 4 can be adjusted in the radial direction r (height adjustment) using adjusting elements 6. These elements are, for example, screw constructions that allow the bearing segment 4 to be fixed in a predefined radial position relative to the bearing housing 5. The adjustability of the bearing segment 4 by the adjusting elements 6 is indicated by arrows on the adjusting elements 6.

[0024] The aim of the above-described procedure for adjusting the individual bearing segments 4 is to position all bearing segments radially so that, given a specific bearing load, all bearing segments are loaded as evenly as possible.

[0025] Accordingly, a finite element analysis (FEA) is first used to calculate, for an initial radial position r0, the load that the individual bearing segments have to bear, taking into account the local stiffness of the bearing housing 5 and the expected bearing load. This will regularly result, when specifying the same initial radial position for all bearing segments 4, in those bearing segments located at stiffer points of the bearing housing being subjected to a higher load than those located at less stiffer points.

[0026] Now the FEA can be repeated with modified radial positions, which in Fig.Figure 2 indicates the positions r1, r2, and r3. Consequently, the load values ​​for the individual bearing segments change.

[0027] By varying the values ​​for the radial positioning, optimized values ​​for the individual radial positions of the individual bearing segments 4 can now be determined. Well-known optimization algorithms can be used for this purpose.

[0028] In principle, the procedure can also be implemented in an elementary way by assuming a lower radial positioning for those bearing segments 4 that have to bear a higher load than the average across all bearing segments and / or by assuming a higher radial positioning for those bearing segments 4 that have to bear a lower load than the average across all bearing segments.

[0029] In this way, the load on all bearing segments can be iteratively adjusted by determining the respective radial positioning, which, after the calculation has been carried out, can then be used as the basis for the assembly of the main bearing. Reference symbol list 1 Main Camp 2 Bearing ring (inner bearing ring) 3 Bearing ring (outer bearing ring) 4 bearing segment 5. Surrounding component (bearing housing) 6 Actuator r radial position of the bearing segment r0 initial radial positioning r1 changed radial positioning r2 further modified radial positioning r3 further modified radial positioning

Claims

[1] Method for optimizing the load of a main bearing (1) of a wind turbine, wherein the main bearing (1) is designed as a hydrodynamic sliding bearing, in which at least one of the bearing rings (2, 3) consists of a number of bearing segments (4) which connect directly or indirectly to each other 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 an surrounding component (5), characterized by that the procedure includes the following steps: a) Performing a numerical simulation for each of the bearing segments (4) of the bearing ring (2, 3) or a numerical simulation that considers all bearing segments (4), in which the load on the bearing segment (4) when arranged on or in the surrounding component (5) is calculated when subjected to the expected bearing load and at a given initial radial positioning (r0) of the bearing segment (4) relative to the surrounding component (5); b) Performing 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 arranged on or in the surrounding component (5) is calculated when subjected to the expected bearing load and with a given changed radial positioning (r1) of the bearing segment (4) relative to the surrounding component (5); c) Comparison of the loads on the bearing segments (4) determined according to steps a) and b) and selection of the radial positions for all bearing segments (4) where a load on all bearing segments (4) can be expected to be as uniform as possible; d) Adjustment of the radial positioning of all bearing segments (4) according to step c). [2] Method according to claim 1, characterized by , that after step b) and before step c) of claim 1 the following step is performed: 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 modified radial positionings (r2, r3, ...) 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 selection. [3] Method according to claim 1 or 2, characterized bythat the numerical simulation is a finite element analysis (FEM). [4] Method according to any one of claims 1 to 3, characterized by , 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 any one of claims 1 to 4, characterized by , that it is carried out for a hydrodynamic sliding bearing whose outer ring (3) has at least 6 bearing segments. [6] Method according to any one of claims 1 to 5, characterized by , that it is only carried out for the bearing segments (4) of the outer bearing ring (3).

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