Bearing arrangement, wind turbine and method for adjusting a bearing arrangement

Abstract

Bearing arrangement (1) with force sensor (9), comprising a housing-fixed bearing ring (10), namely outer ring, in which a plurality of sliding bearing segments (4), which together are provided for the radial support of a shaft, are mounted, wherein each sliding bearing segment (4) is supported on the bearing ring (10) by an axial sliding bearing (3), and wherein a force measuring ring (6) is provided for measuring a force acting between the sliding bearing segment (4) and the bearing ring (10), which is arranged between the axial sliding bearing (3) and the bearing ring (10).

Description

[0001] The invention relates to a bearing arrangement designed as a sliding bearing with a load measuring device, i.e., force sensors. Furthermore, the invention relates to a wind turbine and a method for adjusting a bearing arrangement, particularly in a wind turbine.

[0002] JP 2004 144 596 A2 discloses a device for detecting an axial force acting on a plain bearing that supports a shaft. A ring is mounted on the shaft, which has a circumferential collar, i.e., a radially outwardly directed rim. The collar can bear against a housing-mounted disk in the axial direction of the device according to JP 2004 144 596 A2. The disk, in turn, bears against an element equipped with force measurement technology.

[0003] A device disclosed in JP 2011 169 418 A is designed for force measurement on an axial bearing. The axial bearing comprises several pads arranged in an annular space. Furthermore, the axial bearing includes several force measuring cells associated with the pads.

[0004] A device for measuring axial bearing forces, known from DE 10 2008 052 189 A1, is intended in particular for measuring forces occurring on an exhaust gas turbocharger. It is proposed to measure axial forces using a strain gauge circuit. Furthermore, the device according to DE 10 2008 052 189 A1 includes an evaluation unit.

[0005] Another device with a strain sensor is disclosed, for example, in DE 10 2018 132 252 B4. The strain sensor is intended to detect strain in at least one direction of movement and, in the case of DE 10 2018 132 252 B4, is used on a linear bearing. Temperature-related fluctuations in the amount of strain are to be compensated.

[0006] Various measuring devices that detect loads on bearings using optical means are described, for example, in documents DE 10 2004 043 754 B3 and DE 10 2004 043 752 B4.

[0007] DE 38 28 550 A1 discloses a force measuring ring intended for use in a spindle drilling machine. The force measuring ring comprises a ring body and several strain gauges.

[0008] A thrust sensor assembly described in EP 1 007 925 B1 comprises several pressure plate assemblies, wherein at least one of the pressure plate assemblies engages at least indirectly with a shaft in order to move axially with the shaft. An elastically compressible buffer is located between the two pressure plate assemblies. A pressure transducer is mounted on one of the two pressure plate assemblies.

[0009] With regard to wind turbines, DE 10 2018 003 437 A1 discloses that the rotor shaft, in particular in the area of ​​the first radial bearing, may have at least one spacer element to enable precise axial positioning and / or adjustment and / or bearing preload.

[0010] Bearing arrangements for wind turbines with force sensors are also known from the publications DE 10 2020 133 993 A1, DE 10 2017 111 745 A1, EP 3 708 831 A1 and US 2017 0 096 984 A1.

[0011] The invention is based on the objective of providing advanced means of force sensing in bearing arrangements, particularly in wind turbines, compared to the prior art, with the aim of enabling use during the assembly of a bearing, but also within the later, fully assembled system.

[0012] This problem is solved according to the invention by a bearing arrangement equipped with a force sensor according to claim 1. The bearing arrangement is particularly suitable for use in a wind turbine according to claim 6. Furthermore, the problem is solved by a method for adjusting a bearing arrangement as designed according to claim 7. The embodiments and advantages of the invention explained below in connection with the adjustment method also apply mutatis mutandis to the devices, i.e., the wind turbine and the bearing arrangement, and vice versa.

[0013] According to claim 1, the bearing arrangement equipped with a force sensor comprises a housing-mounted bearing ring, namely the outer ring. The term "outer ring" is used here regardless of whether it is constructed as a single piece or in multiple parts, and a construction consisting of several spaced-apart elements is also possible. Likewise, the outer ring can be directly or indirectly connected to a housing or even formed directly by the housing. In any case, several plain bearing segments, which together are intended for the radial support of a shaft, are mounted in the outer ring. Each plain bearing segment is supported on the bearing ring by an axial plain bearing. A force-measuring ring is provided for measuring a force acting between the plain bearing segment and the bearing ring; this ring is arranged between the axial plain bearing and the bearing ring.

[0014] The bearing arrangement as a whole is specifically designed for the hydrodynamic sliding support of a shaft. Each of the sliding bearing segments is capable of supporting the shaft in the radial direction. In the case of a large bearing arrangement, the sliding bearing segments located in the lower region of the arrangement are particularly subject to gravitational loads. Therefore, in numerous applications, it is advantageous not to position the sliding bearing segments at equal angular intervals around the central axis of the shaft and the entire bearing arrangement, but rather to provide a denser arrangement of sliding bearing segments in the lower region of the bearing arrangement compared to the rest of the arrangement.If the space available for installing the sliding bearing segments is geometrically divided into four segments of 90 degrees each – that is, a lower left segment, an upper left segment, a lower right segment, and an upper right segment – ​​then sliding bearing segments can be arranged in all four segments, or in some applications, only in the two lower segments. In any case, when viewed in the circumferential direction of the bearing arrangement, there are gaps between individual sliding bearing segments.

[0015] The axial plain bearings, which support the individual bearing segments, transmit forces that act between the shaft and the bearing ring, at least approximately in the radial direction, relative to the central axis of the entire bearing assembly. This direction, viewed from the perspective of the axial plain bearings, is their axial direction. These axial plain bearings include, for example, rocker arm bearings or spherical plain bearings. In each case, placing the force-measuring rings between each axial plain bearing and the bearing ring provides both a space-saving and well-protected housing for the force-measuring sensors, while also achieving a sufficiently high precision for force measurement in this application. Force-measuring rings can be assigned to either a subset of the bearing segments or to all of them.

[0016] The force-sensing ring is positioned, for example, between a housing plate belonging to the axial sliding bearing and the bearing housing. It is possible that the housing plate contacts both the force-sensing ring and the bearing ring. In particular, the force-sensing ring can be arranged in a recess of the bearing ring that is at least largely covered by the housing plate.

[0017] The bearing arrangement can include multiple hydraulic cylinders, which are positioned in the lower half of the bearing ring and designed to lift a shaft along with a load connected to it. The hydraulic cylinders are particularly useful in cases where the supported shaft loads the bearing arrangement not only with its own weight, but also with machine elements connected to the shaft.

[0018] The procedure for setting up a bearing arrangement, which may be intended for installation in a wind turbine or may already be installed in a wind turbine, generally comprises the following steps: - Provision of a bearing arrangement according to claim 1 and of a shaft placed in the bearing arrangement, - Measurement of forces acting between the shaft and the bearing ring by means of a plurality of force measuring rings arranged between the shaft and the bearing ring, - Lifting the shaft within the bearing arrangement, - Adjustment of all sliding bearing segments such that a force acts between each sliding bearing segment and the shaft, - Relief of at least a subset of the sliding bearing segments in such a way that a defined clearance of the bearing arrangement is achieved.

[0019] Particularly in cases where the shaft is not loaded by other machine elements, it is possible to lift the shaft solely using the plain bearing segments. Alternatively, the shaft can be lifted hydraulically, using several hydraulic cylinders positioned between individual plain bearing segments, especially in the lower half of the bearing assembly. First, the hydraulic cylinders are used to establish a uniform load on the plain bearing segments mounted in the lower half of the assembly. Then, they are used to establish a uniform load on the plain bearing segments located in the upper half of the assembly, and finally, to establish a uniform load on the plain bearing segments located in the left and right halves of the assembly.

[0020] An embodiment of the invention is explained in more detail below with reference to a drawing. The drawing shows, in a simplified form: Fig. 1 Components of a segmented bearing arrangement with force sensors in a sectional view, Fig. 2 the arrangement according Fig. 1 in a further representation, Fig. 3 and Fig. 4 different variants of adjustment procedures are shown in flowcharts, which are applied to the bearing arrangements according to the Fig. 1 and Fig. 2 are feasible.

[0021] A bearing arrangement, designated by reference numeral 1, is designed as a segmented plain bearing and is intended for use as the main rotor bearing in a wind turbine (not shown). The bearing arrangement 1 comprises an annular housing element 2, which in this case functions as an outer ring 10 of the bearing arrangement 1, i.e., it forms a bearing ring. The bearing ring 10 can be composed of any number of individual parts. Within the housing element 2, several plain bearing segments 4 are supported by axial plain bearings 3. The characterization of the latter plain bearings 3 as axial plain bearings means that an axial force acts on the respective bearings 3. With respect to the entire bearing arrangement 1, this is a radial force. The corresponding radial forces act between a shaft supported by the bearing segments 4 and the outer ring 10.Thanks to the axial sliding bearings 3, each bearing segment 4 is angularly adjustable to a limited extent. Each axial sliding bearing 3 has at least one degree of freedom, which is the case when configured as a rocker bearing. In the exemplary embodiment, as is characteristic of spherical plain bearings, the axial sliding bearings 3 have several degrees of freedom.

[0022] Viewed in a direction parallel to the longitudinal axis of the shaft to be supported by means of the bearing arrangement 1, as shown from Fig. As shown in Figure 2, four quadrants QI to Q IV of the bearing arrangement 1 can be defined. In each of these quadrants QI, Q II, Q III, Q IV, in the sketched embodiment, there are two sliding bearing segments 4 and, accordingly, also two axial sliding bearings 3, which in this case are designed as spherical bearings. In the two lower quadrants Q III, Q IV, two hydraulic cylinders 8 are additionally placed, which, as will be explained in more detail below, can be used in adjusting the bearing arrangement 1.

[0023] Each axial sliding bearing 3 is supported, as shown from Fig. As shown in Figure 1, the outer ring 2 is connected to a segment support 5, also referred to as a housing plate. Screws 7 are provided for fastening the segment support 5 to the housing element 2. A recess 11 is formed by the housing element 2, which is covered by the housing plate 5. A measuring ring 6 for detecting a force acting on the axial sliding bearing 3 is located in the recess 11, but does not completely fill it. The measuring ring 6 is part of a force sensor assembly designated as 9.

[0024] A first possibility for setting up the bearing arrangement 1 is described below using Fig. 3 explained. Here, S1 denotes the start of the adjustment procedure. The positioning of the shaft in the bearing arrangement 1, designated as step S2, can take place at any time before the subsequent steps are carried out. In the scenario according to Fig. 3. It is assumed that the shaft is not significantly loaded by other machine elements, such as a rotor of a wind turbine connected to the shaft.

[0025] In step S3, the shaft, which initially rests on the sliding bearing segments 4 in the lower quadrants Q III, Q IV, without touching the sliding bearing segments 4 in the two upper quadrants QI, Q II, is raised by a defined amount.

[0026] This is done by adjusting the sliding bearing segments 4 located in the two lower quadrants Q III, Q IV.

[0027] In the following step S4, it is checked whether the shaft is in contact with all plain bearing segments 4. If this is not the case, step S3 is repeated. Otherwise, in step S5, the load on the bearing segments 4 is increased further. In step S6, the resulting loads are measured. If necessary, the load on the plain bearing segments 4 is increased again in step S5. Finally, after repeating steps S5 and S6 several times, a uniform load on all axial plain bearings 3 is achieved.

[0028] In the following step S7, the height of the sliding bearing segments 4 is reduced again with the aim of adjusting the clearance. A sliding bearing segment 4 is considered raised when its distance from the central axis of the bearing arrangement 1 is reduced. This applies regardless of which quadrant QI to QIV the sliding bearing segment 4 is located in. Thus, raising a sliding bearing segment 4 in one of the two upper quadrants QI, QII is accompanied by a geodetic lowering of the respective sliding bearing segment 4. In step S8, it is checked whether the desired clearance setting has already been achieved. If necessary, step S7 is repeated. Finally, step S9 marks the end of the adjustment procedure. Fig. 3.

[0029] The flowchart according to Fig. Step 4 refers to a scenario in which the shaft supported in bearing arrangement 1 is already installed in a wind turbine and loaded with the mass of the turbine rotor. In this case, the hydraulic cylinders 8 are used to relieve the load on the shaft. Step S1 also marks the start of the adjustment procedure in this case. In step S2, the forces acting on the bearing segments 4 located in the lower quadrants Q III and Q IV are measured. In step S3, target positions of the individual sliding bearing segments are calculated with the aim of achieving a uniform load distribution. The unloading of the shaft by actuating the hydraulic cylinders 8 begins in step S4.

[0030] Subsequently, in step S5, the height settings of the bearing segments 4 located in the lower quadrants Q III, Q IV are changed.

[0031] In step S6, load measurements are taken in the lower segments Q III and Q IV. Steps S4 and S5 are repeated as necessary until the forces in the two lower bearing segments Q III and Q IV are at least approximately evenly distributed. In step S7, the shaft height is adjusted using the hydraulic cylinders 8. The resulting displacement is measured in step S8. In step S9, the clearance is adjusted. Based on a force measurement, step S10 checks whether the goal of an even load distribution on the sliding bearing segments 4 in the area of ​​the upper segments QI and Q II has been achieved. If this is not the case, the height adjustment parameters are redefined in step S11, and steps S7 to S9 are repeated.

[0032] Otherwise, the horizontal position of the shaft is adjusted in steps S12 to S15. In step S12, the hydraulic cylinder 8 closest to the boundary between quadrant QI and quadrant Q IV, i.e., the one closest to the 3 o'clock position, is actuated first. In this case, this is a hydraulic cylinder 8 in the 4 to 5 o'clock position. By actuating this hydraulic cylinder 8, the shaft can be adjusted relative to the arrangement shown. Fig. 2, are shifted to the left. This results in increased loads in quadrants Q II and Q III, which are measured in step S14. In step S15, it is checked whether the sliding bearing segments 4 in quadrants Q II and Q III are at least approximately uniformly loaded. As soon as this is the case, steps S12 to S14 are repeated, whereby in this case the load on the sliding bearing segments 4 in quadrants QI and Q IV is adjusted using a hydraulic cylinder 8 located in quadrant Q III. After forces acting laterally have also been adjusted in this way, the adjustment procedure is carried out according to Fig. 4 completed with step S16. Reference symbol list 1 Storage arrangement 2 Housing element 3 axial plain bearings 4 plain bearing segment 5-segment support, housing plate 6 force measuring ring 7 screw 8 hydraulic cylinders 9 Force sensors 10 Outer ring, bearing ring 11 Exclusion Q I...Q IV Quadrant S1...S16 Step

Claims

Bearing arrangement (1) with force sensor (9), comprising a housing-fixed bearing ring (10), namely outer ring, in which a plurality of sliding bearing segments (4), which together are provided for the radial support of a shaft, are mounted, wherein each sliding bearing segment (4) is supported on the bearing ring (10) by an axial sliding bearing (3), and wherein a force measuring ring (6) is provided for measuring a force acting between the sliding bearing segment (4) and the bearing ring (10), which is arranged between the axial sliding bearing (3) and the bearing ring (10). Bearing arrangement (1) according to claim 1, characterized in that the force measuring ring (6) is placed between a housing plate (5) belonging to the axial sliding bearing (3) and the bearing ring (10). Bearing arrangement (1) according to claim 2, characterized in that the housing plate (5) contacts both the force measuring ring (6) and the bearing ring (10). Bearing arrangement (1) according to claim 2 or 3, characterized in that the force measuring ring (6) is arranged in a recess (11) of the bearing ring (10) which is at least mostly covered by the housing plate (5). Bearing arrangement (1) according to one of claims 1 to 4, characterized by a plurality of hydraulic cylinders (8) which are arranged in the lower half (Q III, Q IV) of the bearing ring (10) and are designed to lift a shaft together with a load connected to the shaft. Wind turbine comprising a bearing arrangement (1) according to claim 1. Method for adjusting a bearing arrangement (1), comprising the following steps: - Provision of a bearing arrangement (1) comprising several sliding bearing segments (4) according to claim 1 and a shaft placed in the bearing arrangement (1), - Measurement of forces acting between the shaft and a bearing ring (10) of the bearing arrangement (1) by means of a plurality of force measuring rings (6) arranged between the shaft and the bearing ring (10), - Lifting the shaft within the bearing arrangement (1), - Adjustment of all sliding bearing segments (4) such that a force acts between each sliding bearing segment (4) and the shaft, - Relief of at least a subset of the sliding bearing segments (4) such that a defined clearance of the bearing arrangement (1) is established. Method according to claim 7, characterized in that the shaft is lifted exclusively by means of the sliding bearing segments (4). Method according to claim 7, characterized in that the shaft is hydraulically lifted, wherein hydraulic cylinders (8) which are arranged between individual sliding bearing segments (4) are used to first apply a uniform load to the sliding bearing segments (4) mounted in the lower half (Q III, Q IV) of the bearing arrangement (1), then a uniform load to the sliding bearing segments (4) located in the upper half (QI, Q II) of the bearing arrangement (1), and finally a uniform load to the sliding bearing segments (4) located in the left half (Q II, Q III) and in the right half (QI, Q IV) of the bearing arrangement (1).

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