Motor generator for wind turbine, inner stator of motor generator for wind turbine, and wind turbine

Abstract

A motor generator for a wind turbine (1), comprising at least one brake support plate (23) on which at least one brake arrangement (21) is mounted, an outer rotor (11) rotatably mounted relative to the brake support plate, wherein the at least one brake arrangement (21) is adapted to interact with at least one brake disc (22) attached to the rotor (11) to brake a relative rotation between the rotor (11) and the at least one brake support plate (23) on which the air gap fixing element (33) is mounted, the at least one air gap fixing element (33) is mounted on the at least one brake arrangement (21) and is adapted to be in contact with the at least one brake disc (22) when the distance between the at least one brake disc (22) and the brake support plate (23) and / or between the inner stator (10) of the motor generator (7) and the rotor (11) decreases below a predetermined reference value, wherein the at least one air gap fixing element (33) is mounted on the at least one brake arrangement (21).

Description

Technical Field

[0001] The present invention relates to a dynamoelectric machine for a wind turbine, comprising at least one brake support plate on which at least one brake arrangement is mounted, an outer rotor rotatably mounted relative to the brake support plate, wherein the at least one brake arrangement is adapted to interact with at least one brake disc attached to the rotor in order to brake relative rotation between the rotor and the at least one brake support plate, wherein an air-gap fixing element is mounted on the brake support plate and is adapted to come into contact with the at least one brake disc when a distance between the at least one brake disc and the brake support plate and / or between an inner stator and a rotor of the dynamoelectric machine decreases below a predetermined reference value. Background Art

[0002] In particular, for maintenance purposes, it may be necessary to brake (i.e., slow down or lock) the rotation of a wind turbine's motor-generator. The rotation of the motor-generator and / or corresponding components of the wind turbine itself can pose a danger to service personnel working near these components. Therefore, a braking system for a wind turbine's generator is required to slow down and / or lock the rotation or movement of these components. For this purpose, a braking arrangement is provided, which is typically mounted on a non-rotatable brake support plate.

[0003] Another aspect of modern wind turbines is the need for air gap securing systems. Wind turbines typically include a hub with several blades, mounted so that it can rotate about an axis of rotation. The wind-driven rotation of the hub is transmitted to the rotor of the motor-generator or dynamo-electric generator, respectively. An air gap is provided between the rotor and the stator, typically several millimeters in height. In particular, under heavy displacement loads, which may be caused by gusts of wind, strong turbulence, or bearing damage in the dynamo-electric generator, the relative position between the rotor and stator may change, causing the height of the air gap to vary. In extreme cases, the height of the air gap may become zero, i.e., the air gap closes, causing the stator and rotor to directly contact each other. This can cause damage to the stator and / or rotor. Therefore, it is necessary to ensure the presence of an air gap. To this end, an air gap securing element is provided, which is arranged on the brake support plate to ensure that at least a small air gap is maintained even under heavy loads. Examples of corresponding brake systems and air gap securing systems are disclosed in EP 2976711 A1 and EP 2747252 A1.

[0004] US 2011 / 0121579 A1 discloses a braking system for a wind turbine generator. The stator comprises a lamination stack and a brake caliper system. The rotor comprises a brake disc. The brake caliper system comprises a plurality of centrally mounted flanges arranged on the shaft. The radial distance between the brake disc and the brake caliper system is such that, if the air gap becomes so narrow that the stator is about to strike the rotor (potentially causing damage to the generator), the brake disc will strike the caliper system or the flanges, respectively.

[0005] Other concepts for wind turbine generators are disclosed in US 2012 / 0080969 A1 and US 2015 / 0204308 A1.

[0006] The object of the present invention is to achieve an enhanced system with respect to the braking system and the air gap fixing system of a wind turbine, in particular with respect to compact design, flexible construction and efficient implementation of the functionality of the air gap fixing system. Summary of the Invention

[0007] This object is solved by a dynamoelectric machine as initially described, wherein the at least one air-gap fixing element is mounted on the at least one braking arrangement. Basically, but not according to the invention, the at least one air-gap fixing element can be part of the at least one braking arrangement.

[0008] According to the invention, the brake support plate serves several purposes. On the one hand, the brake support plate serves as a component on which the brake arrangement is mounted. On the other hand, the brake support plate serves as a carrier for the air gap fixing element. The brake support plate can be disc-shaped and preferably mounted non-rotatably in the electric generator. The brake support plate can be made of metal, in particular steel. The brake support plate can have several, in particular three, flange-like plate wings, each of which has a brake arrangement mounted on it. As will be described in more detail later, the brake support plate can be a component of the stator of the electric generator. Alternatively, the brake support plate is a separate component with respect to the stator. In this embodiment, the brake support plate and the stator can be mounted on a common, non-rotatable shaft of the electric generator.

[0009] The brake disc may be an annular component. It may be attached to the rotor, in particular to a flange on its axial front face. The brake disc may be made of metal.

[0010] The stator is an inner stator, and the rotor is an outer rotor, i.e., the rotor can be referred to as an outer rotor. At least a portion of the outer rotor extends along a section of the electric generator that is located radially outside the stator. The rotor is rotatably mounted relative to the axis of rotation. The stator can be cylindrical, and the rotor can have the shape of a hollow cylinder. The central axes of the respective cylinders are preferably the same and also the same as the axis of rotation of the rotor. Therefore, the axis of rotation extends in the longitudinal or axial direction of the stator, rotor, and / or electric generator, respectively. In this embodiment, the air gap also includes the shape of a hollow cylinder arranged between the stator and the rotor.

[0011] Regarding the definition of direction, a direction pointing perpendicularly away from the rotation axis may be defined as a radial direction. A direction pointing perpendicularly away from the radial direction and toward a point on the rotor rotating about the rotation axis may be defined as a circumferential direction. The rotation axis of the rotor may extend along the main axis of the wind turbine.

[0012] The motor-generator can be a permanent magnet generator, having a plurality of permanent magnets on a rotor and an electrical circuit formed by a plurality of stator windings arranged as coils on a stator. The rotation of the rotor causes a change in the magnetic field in the wires of the stator windings, which in turn generates an electric current. If the motor-generator is provided in a wind turbine, the wind-driven rotation of the rotor generates an electric current in the electrical circuit, which is used to generate energy or electricity. The output power of the motor-generator can be in the range of several megawatts, in particular between 1 and 40 megawatts.

[0013] The motor-generator may be a direct drive generator.In this embodiment, the wind turbine or generator is gearless, which means that the gearbox is replaced by a motor-generator which is a multi-pole generator, which preferably constitutes a synchronous generator.

[0014] As previously described, in certain circumstances, such as when heavy loads act on components of the motor-generator, the relative radial position between the stator and rotor, and therefore between the brake disc and the brake support plate, may change. Consequently, the width of the air gap may change. In extreme cases, the air gap width may even reach zero, causing the rotor and stator to contact each other, potentially damaging the respective components. To prevent this, an air gap fixing element is provided. The air gap fixing element acts as a support element and contacts the brake disc when the width of the air gap and / or the radial distance between the brake disc and the brake support plate decreases below a predetermined reference value. In this case, frictional contact occurs between the air gap fixing element and the brake disc. Once the air gap fixing element contacts the brake disc, other components of the stator and rotor cannot contact each other because further reduction in the air gap width is prevented. Therefore, when the air gap width decreases below a predetermined reference value, the air gap fixing element acts as a guide for the brake disc and, therefore, the rotor. The predetermined reference value can be a value that safely prevents contact between components of the stator and rotor. The air gap fixing element is made of a material that can withstand frictional contact with the brake disc and is suitable for wear, in particular cast iron or a plastic material.

[0015] According to the present invention, the air-gap fixing element is mounted on the braking arrangement. Thus, the element(s) of the air-gap fixing system and the element(s) of the braking system are, on the one hand, separate components, but on the other hand form a common device or assembly. Alternatively, but not according to the present invention, the air-gap fixing element can be part of the braking arrangement, i.e., a functional component of the braking arrangement. In both embodiments, a compact design of the respective system can be achieved, and in particular with the second embodiment, the number of respective components and / or the overall weight of the generator can be reduced.

[0016] According to a preferred embodiment of the invention, the at least one braking arrangement comprises two brake calipers, between which a portion of a brake disc is arranged and which are adapted to frictionally interact with the brake disc in order to brake relative rotation between the rotor and at least one brake support plate. Each of the brake calipers preferably comprises a lateral side pointing towards the respective lateral side of the other brake caliper and the brake disc. Brake pads can be arranged on these sides. The brake calipers, in particular, are plate-shaped and can be moved towards each other in a longitudinal direction such that the distance between the brake calipers is reduced. Since the brake disc is located between the brake calipers, this movement causes frictional interaction between the brake calipers and / or the brake pads, respectively, in order to brake (i.e. reduce, slow down or lock) relative rotation between the rotor and the brake support plate or the stator, respectively.

[0017] Preferably, the at least one braking arrangement may comprise a spacer element for fixing a specified distance between the brake calipers. The at least one air gap fixing element may be mounted on the spacer element or be at least a part of the spacer element. According to the invention, the at least one air gap fixing element may be mounted on the spacer element. The spacer element may be located between the brake calipers and, with respect to the radial direction, below the brake disc. The spacer element ensures that the distance between the brake calipers with respect to the axial direction is the desired distance and ensures the required position of the brake calipers relative to the brake disc. The spacer element may be block-shaped and comprise, in particular, the shape of a bent cube. The extension of the spacer element with respect to the longitudinal direction may be slightly smaller than the extension of the brake disc with respect to the longitudinal direction to allow frictional interaction between the brake caliper and the brake disc.

[0018] At least one component of at least one of the at least one brake arrangement, in particular a brake caliper and / or a spacer element, can be mounted to the brake support plate via a foot element that, in particular, widens toward the respective brake support plate. The foot element comprises at least one, in particular, wing-shaped carrier element, with a shoe element arranged on the carrier element. The at least one air gap fixing element can be mounted on the shoe element or can be at least a portion of the shoe element. However, according to the present invention, the at least one air gap fixing element can be mounted on the shoe element. The foot element of the brake arrangement can include a base section, wherein the base section is attached to the at least one brake support plate, in particular by welding and / or bolting and / or screwing. The cross-section of the foot element or the base section can diverge toward the brake support plate, so that the side of the foot element attached to the brake support plate achieves a larger contact area between the brake support plate and the foot element. In particular, the base section can be attached to an attachment plate, which is attached to the brake support plate. The attachment plate and the base section can be manufactured as a single piece.

[0019] The carrier element may be arranged on the base section. The carrier element may extend in an axial direction. The shoe-shaped element may be arranged on an end of the carrier element opposite to an end of the carrier element arranged on the foot element. The shoe-shaped element may extend in a radial direction.

[0020] Basically, at least one of the at least one air gap fixing elements can be block-shaped and implemented by a spacer element and / or a shoe-shaped element. According to the present invention, at least one of the at least one air gap fixing elements can be block-shaped and implemented by a shoe-shaped element. With regard to the embodiment in which the air gap fixing element is implemented by a spacer element, the brake disc is located between the brake calipers so that the inner circumferential surface of the brake disc faces the spacer element. With regard to the embodiment in which the air gap fixing element is implemented by a shoe-shaped element, the inner circumferential surface of the brake disc faces the shoe-shaped element. Therefore, if the width of the air gap changes, the distance between the inner circumferential surface of the brake disc and the spacer element or the shoe-shaped element, respectively, also changes. The spacer element acts as a functional component of the air gap fixing system and the brake system in a synergistic manner as an air gap fixing element. To ensure a sufficient life of the spacer element or the shoe-shaped element, this component can be made of cast iron.

[0021] With regard to the embodiment in which the at least one air gap fixing element is mounted on the spacer element or the shoe-shaped element, at least one of the at least one air gap fixing element can be strip-shaped and arranged along the axial direction of the radial outer surface of the spacer element or the shoe-shaped element. The axial direction of the radial outer surface particularly extends along the circumferential direction. The air gap fixing elements are respectively arranged between the brake disc and the spacer element or the shoe-shaped element to ensure that the inner circumferential surface of the brake disc does not contact the spacer element or the shoe-shaped element, respectively. With respect to their longitudinal direction, the width of the strip-shaped air gap fixing element and the radial outer surface can be equal. The spacer element or the shoe-shaped element can respectively include a slit on its radial outer surface, and at least a portion of the strip-shaped air gap fixing element is arranged in the slit.

[0022] The locking member may be arranged on one of the axial ends of the radially outer surface, wherein at least one of the at least one air gap fixing element may be attached to the spacer element or the shoe-shaped element by the locking member on one of the axial ends of the radially outer surface. The locking member may be attached to a transverse surface of the spacer element or the shoe-shaped element extending in the circumferential and radial directions, in particular to a radially outer end of the transverse surface, respectively.

[0023] Specifically, two locking members as locking brackets can be arranged at two opposite axial ends of the radial outer surface, wherein the locking brackets attach the at least one air gap fixing element to the spacer element or the shoe-shaped element at these positions. Each of the locking brackets may include a slit in which the corresponding axial end of the strip-shaped air gap fixing element is clamped. Each of the locking brackets may be a steel plate or an iron plate, which can be attached to the lateral surface of the spacer element or the shoe-shaped element, respectively, for example, by screw fixing connection. Each of the locking brackets can protrude in the radial direction into the area above the radial outer surface of the spacer element or the shoe-shaped element.

[0024] Alternatively, a locking member serving as a locking bracket may be arranged at one of the two opposite axial ends of the radially outer surface, the one directed away from the front side with respect to the rotation of the rotor. In this embodiment, frictional contact between the air-gap fixing element and the brake disc, which occurs below a predetermined reference value, causes a tensile load to act on the corresponding attachment location of the air-gap fixing element in the circumferential direction.

[0025] Alternatively, a locking member serving as a stopper for blocking movement of the at least one air-gap fixing element in the circumferential direction of the rotor can be arranged at one of the two opposing axial ends of the radially outer surface, the one pointing forward with respect to the rotation of the rotor. In this embodiment, the axially forward face of the air-gap fixing element contacts the stopper, preventing friction-induced movement of the air-gap fixing element in the circumferential direction and, therefore, from its designated position on the spacer element or shoe-shaped element. Therefore, in this embodiment, frictional contact between the air-gap fixing element and the brake disc causes a compressive load to act on the corresponding attachment point of the air-gap fixing element in the circumferential direction.

[0026] Since the width of the air gap, and thus the distance between the inner circumferential surface of the brake disc and the air gap fixing element, is in the order of several millimeters, accurately adjusting the radial position of the air gap fixing element is a challenging task.

[0027] With regard to embodiments in which a strip-shaped air gap fixing element is arranged on the radial outer surface of a spacer element or a shoe-shaped element, at least one shim may be arranged between at least one of the at least one air gap fixing element and the radial outer surface so that the at least one air gap fixing element is arranged at a specified radial position. For the installation process of the electric generator, several shims with different thicknesses may be provided. During or after the air gap fixing element has been arranged on the radial outer surface, a shim having a thickness such that the air gap fixing element is arranged in the correct radial position may be arranged between the air gap fixing element and the radial outer surface of the spacer element or the shoe-shaped element. The shim may be strip-shaped or plate-shaped and, in particular, be made of metal or plastic. Several shims may be arranged adjacently, in particular with respect to the circumferential and / or radial direction.

[0028] The radial outer surface may include at least one groove extending in an axial direction of the radial outer surface, wherein the at least one air gap fixing element includes at least one tongue arranged in the at least one groove, wherein the cross-sections of the at least one groove and the at least one tongue correspond to each other. The tongue arranged in the groove ensures that the relative position between the radial outer surface and the air gap fixing element can be automatically achieved during the manufacturing process simply by inserting the tongue into the groove. To arrange the air gap fixing element on the radial outer surface, the air gap fixing element can be moved in its axial direction to insert the tongue into the groove.

[0029] The cross-sections of the at least one groove and the at least one tongue may be dovetail-shaped, so that the cross-sections widen downwardly in the radial direction, causing the air gap fixing element to be attached to the spacer element with respect to the radial direction.

[0030] As already mentioned, precisely adjusting the radial position of the air gap fixing element is a challenging task. To overcome this problem, with respect to a first possible embodiment, the radially inner surface of the spacer element can be arranged on the supporting surface of the at least one brake arrangement. With respect to a second possible embodiment, the radially inner surface of the shoe-shaped element can be arranged on the supporting surface of the carrier element. In both alternatives, the supporting surface or the radially inner surface includes at least one borehole having an internal thread and in which a screw is arranged, wherein the radial position of the air gap fixing element can be adjusted by screwing the screw. The internal thread of the borehole corresponds to the external thread of the screw, so that screwing the screw causes its radial position to change. A portion of the screw protrudes from the supporting surface or the radially inner surface, respectively. Therefore, the radial distance between the inner surface and the supporting surface, and thus the distance between the radially outer surface of the spacer element or the shoe-shaped element and the inner circumferential surface of the brake disc, respectively, can be adjusted by the length of the protruding portion of the screw. The screw can be a headless screw.

[0031] At least one of the at least one air gap fixing element, in particular the block-shaped air gap fixing element, may be made of cast iron.At least one of the at least one air gap fixing element, in particular the strip-shaped air gap fixing element, may be made of plastic material.

[0032] In a possible embodiment of the present invention, the stator is an inner stator and the rotor is a rotatably mounted outer rotor, wherein the at least one brake support plate is one of several laminated stator plates forming the stator core. In this embodiment, the stator comprises several laminated stator plates forming the stator core. The stator plates, and therefore the stator, may include a plurality of teeth projecting outwardly relative to the radial direction, wherein two adjacent teeth transversely delimit a slot, wherein a section of the stator winding extending in the longitudinal direction of the stator is arranged in the slot.

[0033] Preferably, the at least one brake support plate is at least one axial end plate of the core. The brake support plate forms the axial front face or end face of the stator. Preferably, the brake arrangement is attached to the corresponding axial end face. Alternatively, the at least one brake support plate is at least one axial center plate of the core. In this embodiment, the brake support plate is positioned between two further stator plates in the axial direction. In this embodiment, the brake member may be arranged on the circumferential surface of the brake support plate.

[0034] If the motor-generator is a direct-drive generator, one of the at least one brake support plate can be the non-driven end of a stator plate. In this embodiment, the stator includes a driven end and a non-driven end, which constitute opposite axial end faces or front faces of the stator and extend in the radial direction. The driven end can be tapered relative to the radial direction. The driven end faces the main shaft that connects the rotor of the motor-generator to the rotor of the wind turbine. However, it is also possible that one of the at least one brake support plate is a driven end stator plate.

[0035] In another possible embodiment of the present invention, the stator is an inner stator and the rotor is a rotatably mounted outer rotor, wherein the at least one brake support plate is a separate component relative to the stator. The brake support plate and the stator may be mounted on a common shaft of the dynamo-electric machine. The common shaft may not be rotatable relative to the stationary components of the dynamo-electric machine, in particular relative to a housing in which the stator and rotor are arranged.

[0036] The present invention also relates to an inner stator of a dynamoelectric machine for a wind turbine, comprising at least one brake support plate having at least one brake arrangement mounted thereon, wherein the at least one brake arrangement is adapted to interact with at least one brake disk attached to an outer rotor of the dynamoelectric machine, which is rotatably mounted relative to the brake support plate, to brake relative rotation between the rotor and the at least one brake support plate, wherein an air-gap fixing element is mounted on the brake support plate and adapted to contact the at least one brake disk when the distance between the at least one brake disk or the stator and the rotor decreases below a predetermined reference value. The inner stator is characterized in that the at least one air-gap fixing element is mounted on the at least one brake arrangement. However, depending on the present invention, the at least one air-gap fixing element may be part of the at least one brake arrangement. All advantages and features of the dynamoelectric machine according to the present invention are transferable to the inner stator according to the present invention, and vice versa.

[0037] Furthermore, the invention relates to a wind turbine comprising at least one dynamoelectric machine according to the above description. All advantages and features of the dynamoelectric machine according to the invention and of the inner stator according to the invention can be transferred to the wind turbine according to the invention and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. However, these drawings are schematic diagrams designed for illustrative purposes only and do not limit the present invention. The accompanying drawings schematically show:

[0039] Figure 1 is a view of a wind turbine according to an embodiment of the present invention, which includes a motor-generator according to an embodiment of the present invention,

[0040] Figure 2 To pass through Figure 1 FIG. 1 is a view of a radial section of a motor-generator of a wind turbine comprising an inner stator according to an embodiment of the present invention, wherein the section line is Figure 1 The II–II indication in

[0041] Figure 3 To pass through the first possible embodiment Figure 1 A longitudinal sectional view of a motor-generator of a wind turbine,

[0042] Figure 4 for Figure 3 The generator is made of Figure 3 An enlarged view of the cross section indicated by IV,

[0043] Figure 5 To pass through the second possible embodiment Figure 1A longitudinal sectional view of a motor-generator of a wind turbine,

[0044] Figure 6 According to the first alternative Figure 3 An enlarged view of the braking arrangement of the motor-generator, this first alternative is not according to the invention,

[0045] Figure 7 According to the second alternative Figure 3 An enlarged view of the braking arrangement of the motor-generator, this second alternative according to the invention,

[0046] Figure 8 According to the third alternative Figure 3 An enlarged view of the braking arrangement of the motor-generator, the third alternative according to the invention,

[0047] Figure 9 To pass through Figure 8 a cross-sectional view of the braking arrangement of the motor-generator, and

[0048] Figure 10 For the fourth alternative Figure 3 An enlarged view of the braking arrangement of the motor-generator, the fourth alternative according to the invention. DETAILED DESCRIPTION

[0049] Figure 1 A wind turbine 1 according to an embodiment of the present invention is shown. The wind turbine 1 includes a tower 2, on which a nacelle 3 is arranged. A hub 4 is provided in front of the nacelle 3, and is provided with several, in particular three, blades 5. The hub 4 is mounted so that it can rotate about an axis of rotation 6. The wind-driven rotation of the hub 4 is transferred to a motor-generator 7 according to an embodiment of the present invention, located in the nacelle 3. The rotation of the hub 4 is transferred to the motor-generator 7 by a main shaft 8 extending along the axis of rotation 6. The axis of rotation 6 defines the axial direction of the wind turbine 1 and the generator 7. The axis of rotation 6 is arranged horizontally, but can also be tilted relative to the horizontal. The total height of the wind turbine 1 is approximately tens or hundreds of meters, while the output power of the wind turbine 1 generated by the generator 7 can be in the range of several megawatts, in particular between 1 and 40 megawatts.

[0050] The motor generator 7 includes an inner stator 10 and an outer rotor 11 according to an embodiment of the present invention. The stator 10 and the rotor 11 are arranged within the housing 9 of the generator 7. The stator 10 is non-rotatably mounted, while the rotor 11 is connected to the main shaft 8 so that the rotation of the hub 4 is transferred to the rotor 11. Therefore, the rotor 11 can rotate about the rotation axis 6.

[0051] Figure 2A cross section through a section of the electric generator 7 is shown, wherein the cross-sectional plane is perpendicular to the axis of rotation 6. An air gap 12 having a thickness of a few millimeters is arranged between the cylindrical stator 10 and the hollow cylindrical rotor 11. The stator 10 comprises an iron core 13 having a number of laminated stator plates 14. The stator plates 14 are arranged perpendicular to the axis of rotation 6 so that the stack extends along the axis of rotation 6 as the iron core 13. The stator plates 14, and therefore the iron core 13, comprise a plurality of teeth 15, which protrude in a radial direction 16 extending perpendicularly outward from the axis of rotation 6. The teeth 15 are evenly spaced along a circumferential direction 17, which is defined as a direction pointing perpendicularly away from the radial direction 16 towards a point at which the rotor 11 rotates about the axis of rotation 6. Two adjacent teeth 15 delimit transversely a slot, wherein a stator winding 18 for realizing a coil is arranged in the slot. The winding 18 comprises an end winding 20 ( Figure 2 ), each having a curved shape and connecting the windings 18 of several, in particular adjacent slots.

[0052] The rotor 11 includes permanent magnets 19 that are evenly spaced along the circumferential direction 17. The permanent magnets 19 of the rotating rotor 11 and the windings 18 of the stator 10 electromagnetically interact with each other so that current is induced in the windings 18 and thereby the power output of the generator 7 is achieved.

[0053] Next, refer to Figure 3 and Figure 4 . Figure 3 A longitudinal section through the motor-generator 7 along the axis of rotation 6 is shown. Figure 4 Show Figure 3 An enlarged portion of the image is shown, which is indicated by box IV. Figure 3 and Figure 4 The housing 9 is not shown.

[0054] Several brake arrangements 21 are attached to the inner stator 10. Brake disks 22 are attached to the outer rotor 11. The brake arrangements 21 are adapted to interact with the brake disks 22 to brake, or in other words, slow down or decelerate, the rotation of the rotor 11, and thus the rotation of components connected to the rotor 11, such as the main shaft 8 and the hub 4. Typically, if maintenance work must be carried out, the rotation of the hub 4, the main shaft 8, and the rotor 11 must be stopped to avoid danger to the corresponding service personnel. To stop the rotation, in a first step, the pitch angle of each of the blades 5 is adjusted so that aerodynamic effects lead to a deceleration of the rotation. Once the corresponding rotation frequency drops below a certain value, in a second step, the brake arrangements 21 are activated to decelerate the rotation to zero; and in a third step, the rotation of the non-rotating rotor 11 is finally locked.

[0055] Braking arrangement 21 is arranged and attached to a brake support plate 23, which is formed by one of the stator plates 14, and in this embodiment, by way of example, by the axial end plate of core 13, which forms the non-driven end stator plate of motor-generator 7 as a direct-drive generator. Braking support plate 23 thus forms an axial front face 24 of core 13, which is opposite the front end of core 13 that faces toward spindle 8 and hub 4.

[0056] The brake support plate 23 has the geometry of a flat cylinder with a circularly bent outer circumferential surface 25 and two circular end plane axial front faces 26, one of which constitutes the axial front face 24 of the core 13. The brake arrangement 21 is attached to the brake support plate 23 at its outer radial end.

[0057] The stator 11 has the shape of a hollow cylinder with the rotation axis 6 as the center line, wherein a flange 27 is provided on the front face of the rotor 11 opposite the main shaft 8. The circular and annular brake disc 22 is attached to the flange 27 by screw fixing means 28.

[0058] As from Figure 3 and Figure 4 It can be seen in particular that the brake arrangements 21 extend radially outwards and the brake disc 22 extend radially inwards, so that a section of each of the brake arrangements 21 and a section of the brake disc 22 are arranged adjacent to each other with respect to the axial direction.

[0059] Figure 5 Another possible embodiment of the motor-generator 7 is shown. Figure 3 and Figure 5 The main difference between the embodiments is that Figure 3 In the embodiment, the brake support plate 23 is realized by one of the stator plates 14; Figure 5 In the embodiment, the brake support plate 23 is a separate component relative to the stator 10. The stator 10 and the brake support plate 23 are attached to a non-rotatably mounted shaft 29 of the motor generator 7. Figure 5 In the embodiment of , the brake support plate 23 is a metal disk having several, in particular three, plate wings extending in the radial direction 16 , wherein a brake arrangement 21 is attached to each of these plate wings.

[0060] Next, refer to Figure 4 , details about the brake arrangement 21 are described. These details also apply to Figure 5The embodiment shown in FIG. The brake arrangement 21 is a caliper brake having two brake calipers 30 adapted to frictionally interact with a brake disc 22 to slow down the relative rotation between the rotor 11 and the stator 10 or between the brake disc 22 and the brake support plate 23, respectively. To this end, the brake arrangement 21 comprises an electromechanical actuator (not explicitly shown in the drawings) to displace the brake calipers 30 in the axial direction so that the brake pads 31 ( Figure 4 ) are in frictional contact with the brake disc 22 arranged between the brake calipers 30.

[0061] The brake arrangement 21 further comprises a spacer element 32 for fixing a prescribed distance between the brake callipers 30. The spacer element 32 is a block-shaped component made of cast iron. With respect to the axial direction, the extension of the spacer element 32 is slightly smaller than the extension of the brake disc 22.

[0062] In summary, the brake arrangement 21 realizes or is a caliper carrier comprising the set of brake calipers 30 and the spacer element 32 . Figure 4 Components without reference numerals carrying the brake caliper 30 and the spacer element 32 may be omitted. In particular, the brake caliper 30 and the spacer element 32 may be connected with axial through-bolts to a foot element 45, which will be described below and which may also be part of the caliper carrier.

[0063] The electric generator 7 includes an air gap fixing element 33, which is adapted to come into contact with the brake disc 22 when the radial distance between the stator 10 and the rotor 11 decreases below a predetermined reference value. Under certain conditions, for example, when heavy loads act on components of the electric generator 7, the relative radial positions between the stator 10 and the rotor 11, and therefore between the brake disc 22 and the air gap fixing element 33, change. As a result, the width of the air gap 12 also changes. In extreme cases, the width of the air gap 12 may become zero, causing the stator 10 and the rotor 11 to come into contact with each other, which may cause damage to the respective components. To avoid this, an air gap fixing element 33 is provided. This element acts as a supporting element, wherein the air gap fixing element 33 comes into contact with the brake disc 22 when the width of the air gap 12 drops below the predetermined reference value or a predetermined reference value. In this case, frictional contact occurs between the air gap fixing element 33 and the brake disc 22 to prevent the width of the air gap 12 from further decreasing, and therefore prevent contact between the stator 10 and the rotor 11. Although in Figure 4 In FIG, the spacer element 32 and the air gap fixing element 33 are indicated as one and the same component, but according to the present invention, the air gap fixing element 33 is mounted on at least one brake arrangement 21, in particular on the spacer element 32. Details about this will be described below.

[0064] refer to Figures 6 to 10 , four different alternatives of the motor generator 7 are shown. Basically, for Figure 3 and Figure 5 The two embodiments of the motor-generator 7 shown in FIG, ie, the embodiment in which the brake support plate 23 is one of the stator plates 14 ( Figure 3 ), or for an embodiment in which the brake support plate 23 is a separate component relative to the stator 10 ( Figure 5 ), each of these alternatives can be implemented.

[0065] refer to Figure 6 , shows a view of a brake arrangement 21 according to a first alternative which is not in accordance with the invention. Figure 6 The drawing planes are perpendicular to the rotation axis 6 and the axial direction. Figure 6 In the embodiment of the present invention, one of the brake calipers 30 is omitted, so that the spacer element 32 becomes visible. According to this alternative, the air gap fixing element 33 is part of the brake arrangement 21. Specifically, the air gap fixing element 33 is a spacer element 32. When the width of the air gap 12 falls below a predetermined reference value, the radially outer surface 37 of the spacer element 32 contacts the inner circumferential surface 51 of the brake disc 22.

[0066] As from Figure 6 As can be seen, the radially inner surface 34 of the spacer element 32 is arranged on a bearing surface 35 of the braking arrangement 21. The bearing surface 35 includes a borehole 36 having an internal thread, in which a screw, exemplarily a headless screw, is arranged, wherein screwing the screw causes the screw to move in the radial direction 16. Thus, the length of the portion of the screw protruding from the bearing surface 35 can be adjusted by moving the screw into a corresponding radial position. Thus, the radial position of the spacer element 32 can be adjusted by screwing the screw, particularly before the spacer element 32 is installed in its determined position. Alternatively, the radially inner surface 34 can include a borehole 36 with a screw. In particular, with respect to the manufacturing process of the dynamoelectric machine 7, the borehole 36 with the screw allows for precise positioning of the spacer element 32 or the air gap fixing element 33, respectively, with respect to the radial direction 16.

[0067] Figure 7Aspects of a motor-generator 7 according to a second alternative embodiment of the present invention are illustrated, showing a perspective view of a brake arrangement 21. In this figure, one of the brake calipers 30 and the portion of the brake arrangement 21 having the bearing surface 35 are omitted. The second alternative embodiment differs from the first alternative in that an air gap securing element 33 is mounted on a portion of the brake arrangement 21, namely, the spacer element 32. Specifically, the air gap securing element 33 is a strip-shaped element made of a plastic material and is arranged along the axial direction of the radially outer surface 37 of the spacer element 32. This axial direction extends along the circumferential direction 17.

[0068] A member 38 is arranged on each axial end of the radially outer surface 37, wherein the air gap fixing element 33 is attached to the spacer element 32 by the locking member 38 on the corresponding axial end. Specifically, each of the locking members 38 is a locking bracket 39 that is attached to one of the lateral surfaces 40 of the spacer element 32 by a screw-fixed connection. The locking bracket 39 protrudes radially outward so that the corresponding axial end of the air gap fixing element 33 is arranged in the slit 41 of the corresponding locking bracket 39.

[0069] To ensure that the air gap fixing element 33 is arranged at a specified radial position, a shim 42 having a certain thickness or height relative to the radial direction 16 is arranged between the air gap fixing element 33 and the radial outer surface 37 of the spacer element 32. Alternatively or additionally, the aspects already explained above regarding the drilling 36 can be implemented in this alternative.

[0070] Next, refer to Figure 8 , a third alternative embodiment of the motor-generator 7 according to the invention is described. Figure 8 In FIG. 2 , a perspective view of the brake arrangement 21 is shown, wherein one of the brake calipers 30 and the brake disc 32 are omitted for better visibility. This alternative is similar to the one already described with the aid of Figure 7 A second alternative is explained. However, the difference is that the radially outer surface 37 of the spacer element 32 comprises a groove 50 extending in the axial direction of the radially outer surface 37. The groove 50 is shown in FIG. Figure 9 middle, Figure 9 A cross-sectional view through the spacer element 32 and the air gap fixing element 33 is depicted.

[0071] As from Figure 9 It can be seen that the air gap fixing element 33 comprises a tongue 43 arranged in a groove 50. The cross sections of the groove 50 and the tongue 43 correspond to each other. For example, these cross sections widen downwards relative to the radial direction 16. Therefore, these cross sections are dovetail-shaped.

[0072] Reference again Figure 8In this alternative, only one locking member 38 is provided as a stopper 44 at one of the opposite axial ends of the radial outer surface 37 pointing to the front side with respect to the rotation of the rotor 11. In other words, the stopper 44 is arranged on the lateral surface 40 of the spacer element 32 arranged in the rotational movement direction of the rotor 11. Figure 8 , the corresponding axial end of the radially outer surface 37 is located on the right side of this figure.

[0073] Alternatively, in this alternative it is possible to provide Figure 7 According to another option, in addition to the stopper 44 , a locking member as a locking bracket 39 can be arranged at one of the two opposite axial ends of the radial outer surface 37 , the other axial end pointing away from the front side with respect to the rotation of the rotor 11 .

[0074] Next, with the help of Figure 10 A fourth alternative embodiment of the motor-generator 7 according to the present invention is described. This figure shows a perspective view of a brake arrangement 21. The components of the brake arrangement 21, namely the brake caliper 30 and the spacer element 32, are attached to the brake support plate 23 by a foot element 45. The foot element 45 includes a base section 46, which is attached to the brake support plate 23, exemplarily by screw fastening means 47. To this end, the base section 46 is connected to an attachment plate 48 of the foot element 45, creating a larger contact area between the foot element 45 and the brake support plate 23. The cross-section of the base section 46 widens toward the brake support plate 23. The base section 46 and the attachment plate 48 are exemplarily welded to each other. In this embodiment, the air gap fixing element 33 is mounted on the foot element 45. Alternatively, it can be part of the foot element 45. These aspects can also be implemented for the other three alternative embodiments.

[0075] With regard to the fourth alternative, a particularly wing-shaped carrier element 49 is mounted on the foot element 45, exemplarily on the base section 46. Alternatively, the wing-shaped carrier element 49 is part of the foot element 45. A block-shaped shoe element 52, which is made of cast iron and implements the air gap fixing element 33, is attached to the carrier element 49. According to this alternative, when the width of the air gap 12 falls below a predetermined reference value, the radially outer surface 37 of the shoe element 52 comes into contact with the inner circumferential surface 51 of the brake disk 22.

[0076] The radially inner surface 34 of the shoe-shaped element 52 is arranged on the bearing surface 35 of the carrier element 49. The bearing surface 35 comprises a screw thread with an inner thread and a screw (in Figure 10As already explained with respect to the first alternative, in this alternative, the radial position of the air gap fixing element 33 can also be adjusted by turning a screw. Alternatively, the radial inner surface 34 can include a borehole 36 with a screw.

[0077] Reference again Figure 10 In this alternative, it is possible that the air gap fixing element 33 is instead a strip-shaped element made of a plastic material, wherein the air gap fixing element 33 is arranged along the axial direction of the radial outer surface 37 of the shoe-shaped element 52. All aspects that have been explained with respect to the second alternative can also be applied to this alternative, in particular with respect to the locking member(s) 38 and / or the shim(s) 42 arranged between the air gap fixing element 33 and the radial outer surface 37 of the shoe-shaped element 52.

[0078] While the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art will be able to devise other variations based on the disclosed examples without departing from the scope of the present invention.

Claims

1. A motor-generator for a wind turbine (1), comprising at least one brake support plate (23) on which at least one brake arrangement (21) is mounted, an outer rotor (11) rotatably mounted relative to the brake support plate (23), wherein the at least one brake arrangement (21) is adapted to interact with at least one brake disc (22) attached to the rotor (11) to brake relative rotation between the rotor (11) and the at least one brake support plate (23), wherein an air gap fixing element (33) is mounted on the brake support plate (23) and is adapted to come into contact with the at least one brake disc (22) when a distance between the at least one brake disc (22) and the brake support plate (23) and / or between an inner stator (10) of the motor-generator (7) and the rotor (11) decreases below a predetermined reference value, characterized in that The at least one air gap fixing element (33) is mounted on the at least one braking arrangement (21).

2. The electric generator according to claim 1, wherein: The at least one brake arrangement (21) comprises two brake calipers (30) between which a portion of the brake disc (22) is disposed and adapted to frictionally interact with the brake disc (22) to brake relative rotation between the rotor (11) and the at least one brake support plate (23).

3. The electric generator according to claim 2, wherein: The at least one brake arrangement (21) comprises a spacer element (32) for fixing a specified distance between the brake calipers (30), wherein the at least one air gap fixing element (33) is mounted on the spacer element (32).

4. The dynamoelectric machine according to claim 1, characterized in that At least one component of at least one of the at least one brake arrangement (21) is mounted to the brake support plate (23) by a foot element (45) which in particular widens towards the respective brake support plate (23), the foot element (45) comprising at least one in particular wing-shaped carrier element (49), wherein a shoe-shaped element (52) is arranged on the carrier element (49), and the at least one air gap fixing element (33) is mounted on the shoe-shaped element (52).

5. The electric generator according to claim 4, characterized in that At least one of the at least one air gap fixing element (33) is block-shaped and is implemented by the shoe-shaped element (52).

6. The dynamoelectric machine according to one of claims 3 to 5, characterized in that At least one of the at least one air gap fixing element (33) is strip-shaped and is arranged along the axial direction of the radially outer surface (37) of the spacer element (32) or the shoe-shaped element (52).

7. The electric generator according to claim 6, wherein: A locking member (38) is arranged on one of the axial ends of the radial outer surface (37), wherein at least one of the at least one air gap fixing element (33) is attached to the spacer element (32) or the shoe element (52) by the locking member (38) on one of the axial ends of the radial outer surface (37).

8. The electric generator according to claim 7, characterized in that - two locking members (38) are arranged as locking brackets (39) at two opposite axial ends of the radially outer surface (37), wherein the locking brackets (39) attach the at least one air gap fixing element (33) to the spacer element (32) or the shoe element (52) at these locations, or a locking member (38) as a locking bracket (39) is arranged at one of the two opposite axial ends of the radially outer surface (37) which is directed away from the front side with respect to the rotation of the rotor (11), or - a locking member (38) as a stop (44) for blocking the movement of the at least one air gap fixing element (33) in the circumferential direction (17) of the rotor (11) is arranged at one of the two opposite axial ends of the radial outer surface (37) pointing to the front side with respect to the rotation of the rotor (11).

9. The dynamoelectric machine according to one of claims 6 to 8, characterized in that At least one shim (42) is arranged between at least one of the at least one air gap fixing element (33) and the radial outer surface (37), so that the at least one air gap fixing element (33) is arranged at a designated radial position.

10. The dynamoelectric machine according to one of claims 6 to 9, characterized in that The radial outer surface (37) comprises at least one groove (50) extending in the axial direction of the radial outer surface (37), wherein the at least one air gap fixing element (33) comprises at least one tongue (43) arranged in the at least one groove (50), wherein the cross sections of the at least one groove (50) and the at least one tongue (43) correspond to each other, wherein these cross sections are in particular dovetail-shaped.

11. The dynamoelectric machine according to one of claims 3 to 10, characterized in that - the radially inner surface (34) of the spacer element (32) is arranged on a bearing surface (35) of the at least one braking arrangement (21), or - the radially inner surface (34) of the shoe-shaped element (52) is arranged on the bearing surface (35) of the carrier element (49), The bearing surface (35) or the radial inner surface (34) comprises at least one borehole (36) having an internal thread and in which a screw is arranged, wherein the radial position of the air gap fixing element (33) can be adjusted by screwing the screw.

12. The dynamoelectric machine according to one of the preceding claims, characterized in that At least one of the at least one air gap fixing element (33), in particular the block-shaped air gap fixing element (33), is made of cast iron, and / or at least one of the at least one air gap fixing element (33), in particular the strip-shaped air gap fixing element (33), is made of plastic material.

13. The dynamoelectric machine according to one of the preceding claims, characterized in that The at least one brake support plate (23) is - one of several laminated stator plates (14) constituting the core (13) of the stator (10), or - a separate component relative to the stator (10).

14. An inner stator (10) of a motor-generator (7) for a wind turbine (1), the inner stator (10) comprising at least one brake support plate (23) on which at least one brake arrangement (21) is mounted, wherein the at least one brake arrangement (21) is adapted to interact with at least one brake disc (22) attached to an outer rotor (11) of the motor-generator (7) rotatably mounted relative to the brake support plate (23) to brake relative rotation between the rotor (11) and the at least one brake support plate (23), wherein an air gap fixing element (33) is mounted on the brake support plate (23) and is adapted to come into contact with the at least one brake disc (22) when the distance between the stator (10) and the rotor (11) decreases below a predetermined reference value, characterised in that The at least one air gap fixing element (33) is mounted on the at least one braking arrangement (21).

15. Wind turbine comprising at least one motor-generator (7) according to one of claims 1 to 13.

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