Stator core for an electric machine

Abstract

The invention relates to a stator core (10) for an electric machine (84), in particular for a generator of a wind turbine (100), comprising a plurality of lamination stacks (12), which as a whole are hollow-cylindrically arranged about a longitudinal axis AL and form a cylindrical outer circumferential surface (14), and at least two receiving elements (16), wherein the at least two receiving elements (16) are secured relative to the outer circumferential surface (14) by means of a potting compound (20). The potting compound (20) acts as a type of shock absorber between the lamination stack (12) and the stator housing (6). A mechanical processing of the receiving elements (16) is dispensed with. The stack can be inserted and centered without heating the housing.

Description

[0001] FLENDER GMBH Düsseldorf, October 14, 2025

[0002] Our reference number: FD45767 - 2024P04718WO

[0003] Flender GmbH

[0004] Alfred-Flender-Str. 77, 46395 Bocholt, Germany

[0005] Stator core for electric machine

[0006] Description

[0007] The invention relates to a stator core for an electric machine, in particular for a generator of a wind turbine, comprising a plurality of laminated cores which as a whole are arranged in a hollow cylindrical shape around a longitudinal axis AL and form a cylindrical outer circumferential surface and at least two receiving elements.

[0008] Cost and space optimization, coupled with increasing performance demands on wind turbines, are leading to ever more compact generators and their components. This results in stator housings that, while maintaining the same overall size and increasing power output, are lighter but subjected to higher operating loads. Vibrations and operating loads induced by magnetic pull, originating from the stator core, are transmitted into the housing. This, in turn, amplifies vibrations, increasing generator operating noise and exceeding customer specifications. EP 3 783 772 Bl is relevant in this context.

[0009] Furthermore, the stator core and stator housing are conventionally machined so that the stator core fits snugly against the stator housing. For this purpose, the stator housing is heated for insertion. After cooling, holes are drilled for dowel pins, the respective dowel pins are reamed, and then driven into the holes. This process is quite labor-intensive, involving significant effort for machining, checking the fits, and preserving the components for subsequent transport to the final assembly site.

[0010] There is a constant need to improve vibration behavior on the one hand and to reduce the high effort required for mechanical processing on the other.

[0011] The object of the invention is to demonstrate measures that enable improved vibration behavior and reduced machining effort.

[0012] The problem is solved by a stator element for an electric machine having the features of claim 1. Preferred embodiments are specified in the dependent claims and the following description, each of which, individually or in combination, can represent an aspect of the invention. When a feature is presented in combination with another feature, this serves only to simplify the presentation of the invention and is in no way intended to imply that this feature cannot also be a further development of the invention without the other feature.

[0013] One embodiment relates to a stator core for an electric machine, in particular for a generator of a wind turbine, with a plurality of laminated cores which as a whole are arranged in a hollow cylindrical shape around a longitudinal axis AL and form a cylindrical outer circumferential surface, and at least two receiving elements concentrically surrounding the outer circumferential surface, wherein the at least two receiving elements are attached to the outer circumferential surface by means of a potting compound.

[0014] The proposed electric machine thus comprises, from radially inner to radially outer, the hollow cylindrical stator core, then at least two mounting elements, and finally a stator housing. The stator core, the respective mounting element, and the stator housing are each rotationally fixed to one another. The rotatably mounted rotor of the electric machine is arranged within the stator core. The respective mounting element can substantially completely, and in particular completely, surround the outer circumferential surface of the laminated core. It is also conceivable that the respective mounting element only partially encloses the stator core. The stator housing, in turn, can completely enclose the respective mounting element in the circumferential direction. Again, it is conceivable that the stator housing only partially encloses the respective mounting element, for example, by two-thirds or half.

[0015] The potting compound is an integral part of the fit, allowing the stator core to be precisely aligned through targeted design of the potting compound. Preferably, the receiving elements are arranged with a radial annular gap relative to the outer circumferential surface, the annular gap being at least partially filled by the potting compound. The radial annular gap can be geometrically minimized, thereby reducing asymmetric acoustic excitation. The potting compound acts as a kind of shock absorber between the laminated core and the stator housing. Machining of the receiving elements is unnecessary. The core can be inserted and centered without heating the housing.

[0016] The receiving elements are arranged axially offset from one another. Preferably, one of the at least two receiving elements is arranged at each axial end of the sheet metal stacks. It is also preferred that the annular gap on each axial side is limited by a sealing element located between the receiving element and the outer circumferential surface of the sheet metal stacks. The sealing elements, which are preferably designed as sealing cords, serve the particular purpose of preventing the potting compound from running laterally during application while it is still liquid. The potting compound can, in particular, be a metal polymer.

[0017] Furthermore, in a preferred embodiment, it may be provided that several axially extending tension bars are arranged distributed over the outer circumferential surface of the sheet metal stacks, wherein the tension bars are arranged in radially inwardly opening recesses of the receiving elements.

[0018] Furthermore, the task is solved by an electric machine comprising a stator and rotor, wherein the stator has a stator core as described.

[0019] Furthermore, the problem is solved by a drive train for a wind turbine for the torque-transmitting connection of a rotor with a generator, comprising a main bearing unit, a main shaft and a gearbox driven via the main shaft, wherein the gearbox drives the generator at least indirectly, characterized in that the gearbox is designed as an electrical machine as described.

[0020] The problem is also solved by a wind turbine comprising a rotor flange with a rotor and a generator, wherein a drive train held on a machine carrier and connecting the rotor flange to the generator is provided, wherein the drive train is designed as described.

[0021] The invention is explained below by way of example with reference to the accompanying drawings and preferred embodiments, wherein the features shown below can represent an aspect of the invention, either individually or in combination. The drawings show:

[0022] Fig. 1: schematic representation of an electric machine,

[0023] Fig. 2a) and 2b): a stator core as a detail and as a detailing, Fig. 3: a further detailing of the stator core according to Fig. 2a), 2b) and Fig. 4: a perspective view of a wind turbine.

[0024] Figure 1 shows an electric machine 84, for example in the form of a generator, which has a hollow cylindrical stator 8 in which a rotor (not shown) is rotatably mounted. The stator 8 and rotor are arranged concentrically about a longitudinal axis AL. The stator 6 comprises a stator core 10 composed of a plurality of laminated cores 12, which forms a cylindrical outer circumferential surface 14. Furthermore, the electric machine 84 has two receiving elements 16, each of which completely encloses the stator core 10. The two receiving elements 16 are arranged offset from each other in the direction of the longitudinal axis AL. This connection is conventionally achieved by welding the stator core 10 or the laminated cores 12 to the respective receiving element 16. The electric machine 84 also has a stator housing 4, which encloses the stator 8 at least to a large extent.

[0025] Figure 2a) shows a stator core 10 in detail without the depicted receiving elements 16, and Figure 2b) shows a detailed view of the stator core 10 with receiving elements 16. The two receiving elements 16 are attached to the outer circumferential surface 14 by means of a potting compound 20. The receiving elements 16 are each arranged at the axial ends of the lamination stacks 12. In this design, the two receiving elements 16 completely surround the outer circumferential surface 14 of each of the two axially outermost lamination stacks 12.

[0026] The receiving elements 16 are arranged with a radial annular gap 18 opposite the outer circumferential surface 14. The annular gap 18 is filled with the potting compound 20. The potting compound 20 can be a metal polymer. The annular gap 18 is bounded on each axial side by a sealing element 22 located between the receiving element 16 and the outer circumferential surface 14 of the sheet metal stacks 12. Several axially extending tension rods 24 are provided and distributed over the outer circumferential surface 14 of the sheet metal stacks 12, the tension rods 24 being arranged in radially inwardly opening recesses 26 of the receiving elements 16.

[0027] Figure 3 shows a further, partial detail of the stator core 10 in the area where a receiving element 16 is held against the outer circumferential surface 14 of the lamination stack 12 by means of the potting compound 20. Figure 4 shows an embodiment of a wind turbine 70. The wind turbine 70 comprises a nacelle 71 to which a multi-blade rotor 72 is rotatably attached. The multi-blade rotor 72 is torque-transmittingly connected to a main shaft 74, the main shaft 74 belonging to a drive train 76. The drive train 76 further comprises a gearbox 78, which is torque-transmittingly connected to the main shaft 74. The gearbox 10 has at least one planetary stage 14 and is in turn coupled to a generator 84 via a main bearing unit 82. A main shaft 74 is provided in the main bearing unit 82.

[0028] Reference symbol list

[0029] 6 Stator housings

[0030] 8 Stator

[0031] 10 Stator core

[0032] 12 sheet metal packages

[0033] 14 External perimeter area

[0034] 16 recording unit

[0035] 18 annular gap

[0036] 20 potting compound

[0037] 22 Sealing element

[0038] 24 Pull rod

[0039] 26 Exclusion

[0040] 70 wind turbines

[0041] 71 gondola

[0042] 72 Rotor

[0043] 74 Main shaft

[0044] 76 Drivetrain

[0045] 78 Rotor flange

[0046] 80 machine carriers

[0047] 82 Main storage unit

[0048] 84 Generator

[0049] 86 gearboxes

Claims

Patent claims 1. Stator unit (10) for an electric machine (84), in particular for a generator of a wind turbine (70), comprising a plurality of laminated stacks (12) which as a whole are arranged in a hollow cylindrical shape around a longitudinal axis (AL) and form a cylindrical outer circumferential surface (14), at least two receiving elements (16) concentrically surrounding the outer circumferential surface (14), wherein the at least two receiving elements (16) are attached to the outer circumferential surface (14) by means of a potting compound (20).

2. Stator core (10) according to claim 1, characterized in that the at least two receiving elements (16) completely surround the outer circumferential surface (14) of the sheet metal stacks (12).

3. Stator unit (10) according to claim 1 or 2, characterized in that one of the at least two receiving elements (16) is arranged at each of the axial ends of the laminated cores (12).

4. Stator kem (10) according to one of claims 1 to 3, characterized in that the receiving elements (16) are arranged with a radial annular gap (18) opposite the outer circumferential surface (14), wherein the annular gap (18) is at least partially filled by the potting compound (20).

5. Stator element (10) according to claim 4, characterized in that the annular gap (18) is opened on each axial side by a space between the receiving element (16) and the The outer circumferential surface (14) of the sheet metal packages (12) is limited by the sealing element (22) that is inserted.

6. Statorkem (10) according to one of claims 1 to 5, characterized in that the potting compound (20) is a metal polymer.

7. Stator element (10) according to one of claims 1 to 6, characterized in that several axially extending tension bars (24) are provided and distributed over the outer circumferential surface (14) of the sheet metal stacks (12), wherein the tension bars (24) are arranged in radially inwardly opening recesses (26) of the receiving elements (16).

8. Electric machine (84) comprising a stator (8) and rotor rotor, characterized in that the stator (8) has a stator core (10) according to one of the preceding claims.

9. Drive train (76) for a wind turbine (70) for torque-transmitting connection of a rotor (72) with a generator (84), comprising a main bearing unit (82), a main shaft (74) and a gearbox (86) driven via the main shaft (74), wherein the gearbox (86) drives the generator (84) at least indirectly, characterized in that the generator (84) is designed as an electric machine according to claim 8.

10. Wind turbine (70) comprising a rotor flange (78) with a rotor (72) and a generator (84), wherein a drive train (76) is provided which is held on a machine carrier (80) and connects the rotor flange (78) to the generator (84), characterized in that the drive train (102) is designed according to claim 9.

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