Drive transmission assembly for wind turbines

Abstract

The wind turbine drive transmission assembly includes a gearbox coupled to a generator for a wind turbine, the generator comprising a stator at a radially outer position and a rotor at a radially inner position, the rotor comprising a cylindrical field structure configured to rotate about a generator rotor axis, the rotor configured to define a central hollow portion, the rotor further comprising a rotor support frame connected to and structurally supporting the cylindrical field structure, the rotor support frame comprising a rotor connection flange attaching the rotor support frame to the cylindrical field structure, a speed increaser connection flange connecting the rotor support frame to an output drive shaft of the speed increaser, and a transition extending between the rotor connection flange and the speed increaser connection flange, the transition being defined at least in part by one or more step areas, the or each step area being shaped to define a surface that is inclined at an angle of less than 30 degrees relative to the rotor axis. Advantageously, the step area provides an integrated platform inside the hollow portion on which service personnel can stand to work inside the generator.

Description

Technical Field

[0001] The present invention particularly relates to a drive transmission assembly for a wind turbine.

Background Art

[0002] A wind turbine converts kinetic energy from the wind into electrical energy using a large rotor having a number of blades. A typical horizontal axis wind turbine (HAWT) includes a tower, a nacelle above the tower, a rotor hub attached to the nacelle, and a plurality of wind turbine blades coupled to the rotor hub. Depending on the wind direction, the nacelle and the blades are rotated by a yaw system that rotates the nacelle and a pitch system that rotates the blades, and are oriented in an optimal direction.

[0003] The nacelle houses, for example, many functional components of the wind turbine including a main shaft, a speed increaser, and a generator, and a conversion device that converts mechanical energy in the rotor into electrical energy for supply to the power grid. The speed increaser increases the rotational speed of the low-speed main shaft and drives the speed increaser output shaft. The speed increaser output shaft drives the generator, and the generator converts the rotation of the speed increaser output shaft into electric power. The electric power generated by the generator can be converted as necessary before being supplied to a suitable consumer, for example, a power grid distribution system. So-called "direct drive" wind turbines that do not use a speed increaser are also known. In a direct drive wind turbine, the generator is directly driven by the main shaft.

[0004] Generally, the generator of a wind turbine is an IPM (Interior Permanent Magnet) electric machine consisting of an external stator assembly surrounding an internal rotor assembly. The IPM internal rotor assembly typically consists of an annular structure including a plurality of annular permanent magnet packages supported on a central axis. The speed increaser output shaft contacts the central axis of the rotor assembly.

[0005] WO2020143888A1 illustrates a specific type of IPM electromachine for use as a wind turbine generator. In this example, the annular structure is supported at one end by an annular support frame. The absence of a central hub in the rotor assembly offers several significant advantages, including reduced cost and weight, and improved cooling airflow. The cooling air supplied to the center of the generator flows freely in the axial and radial directions, effectively cooling the rotor and the generator components located in close proximity. However, further improvements to this design are desirable, for example, to enhance the maintainability of the assembly.

[0006] The object of the present invention is to provide a solution to one or more of the above-mentioned problems. [Overview of the project]

[0007] According to a first aspect of the present invention, a drive transmission assembly for a wind turbine is provided, including a gearbox connected to a generator for a wind turbine. The generator comprises a stator at a radially outward position and a rotor at a radially inward position, the rotor comprising a cylindrical field structure configured to rotate about the rotor axis of the generator, and the rotor is configured to define a central hollow portion. The rotor further comprises a rotor support frame, which is connected to the cylindrical field structure and structurally supports the cylindrical field structure. The rotor support frame comprises a rotor connection flange for attaching the rotor support frame to the cylindrical field structure, a gearbox connection flange for connecting the rotor support frame to the output drive shaft of the gearbox, and a transition portion extending between the rotor connection flange and the gearbox connection flange, the transition portion being at least partially defined by one or more step regions, one step region or each step region being formed to define a surface inclined at an angle of less than 30 degrees with respect to the rotor axis.

[0008] An advantage of the present invention is that the drive transmission assembly includes a gearbox coupled to the generator, configured to facilitate repair and inspection processes in particular. Typically, a drive transmission system including a gearbox coupled to the generator requires all repair and inspection to be performed from an access point outside the generator. However, in the drive transmission assembly of the present invention, the rotor components define a central hollow section suitable for access by maintenance personnel for various repair and inspection operations related to the generator. Furthermore, a step area provides a platform integrated into the hollow section, on which repair and inspection personnel can stand and work inside the generator.

[0009] A single step area, or each step area, may extend circumferentially, either entirely or partially, around the rotor axis. A step area may be a single continuous surface, or it may be defined by multiple separate step areas. In the case of multiple step areas, at least some of them may be separated from each other by reinforcing ribs that provide structural strength to the rotor support structure.

[0010] Advantageously, the transition section defining the step area may include an axially oriented end face which may be substantially aligned with the direction of the speed increaser connection flange and the rotor axis. The end face may define a plurality of access openings which allow a repair technician to access the area outside the rotor support frame during repair operations.

[0011] In some embodiments, the rotor may be housed within a generator repair and inspection cabinet, which may be connected to a speed increaser housing. The generator repair and inspection cabinet may define an internal chamber in which the rotor is housed, and may include one or more closing elements configured to selectively close the opening into the internal chamber defined by the generator repair and inspection cabinet. Thus, the repair and inspection cabinet provides a normally enclosed environment for repair and inspection purposes that can be accessed when needed by repair and inspection technicians. A suitable access control system may be associated with the closing to ensure that access is only possible under safe conditions. Thus, an enclosed environment means that the repair and inspection area can be more easily kept away from contamination.

[0012] The present invention will be described illustratively with reference to the accompanying drawings. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic front view showing a known wind turbine configuration. [Figure 2] Figure 2 shows an exemplary drive transmission component that can be housed within the nacelle of the wind turbine shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of a known configuration, including a generator coupled to a speed increaser, shown at axially spaced positions. [Figure 4] Figure 4 is a perspective view of the generator rotor assembly of the known generator shown in Figure 3, viewed from the non-driven end. [Figure 5] Figure 5 is a perspective view of the generator rotor assembly shown in Figure 4, viewed from the drive end. [Figure 6] Figure 6 is a longitudinal cross-sectional view of a generator rotor assembly according to one embodiment of the present invention, and is a partial schematic view as seen from inside a generator repair and inspection cabinet. The generator rotor assembly includes a cylindrical field structure fitted into a rotor support hub, i.e., a frame, and can be used in a generator as shown in the previous figure. [Figure 7]Figure 7 is a perspective view of the generator rotor assembly from Figure 6, separated from the generator repair and inspection cabinet. [Figure 8] Figure 8 is another front perspective view of the generator rotor assembly from Figure 6, with the cylindrical field structure omitted. [Figure 9] Figure 9 is a perspective view of the generator rotor assembly shown in Figure 7, viewed from the non-driven end. [Figure 10] Figure 10 is an end view of the generator rotor assembly shown in Figures 6 through 9, located inside the generator cabinet, and shows a mechanic standing inside the support frame to access the internal components. [Figure 11a] Figure 11a is an end view similar to Figure 10, showing the access door in a closed position. [Figure 11b] Figure 11a is an end view similar to Figure 10, showing the access door in the open position. [Modes for carrying out the invention]

[0014] The following describes specific embodiments of the present invention, but in order to fully understand the concept of the present invention as defined in the claims, many features will be described in detail. However, it will be apparent to those skilled in the art that the present invention can be implemented without specific details, and that, in some cases, well-known methods, techniques, and structures are not described in detail in order to avoid unnecessarily obscuring the present invention.

[0015] This invention relates, in general terms, to a generator configuration having several advantages related to the maintainability of the generator and the associated speed increaser to which the generator is connected. In particular, the generator configuration provides mechanics with improved access to the inside of the generator, which allows various types of adjustments to be made without disassembling part or all of the generator. This is a significant advantage within the scope of a wind turbine nacelle.

[0016] To place the embodiments of the present invention in an appropriate context, first, refer to FIG. 1, which shows a typical horizontal axis wind turbine (HAWT) in which a generator rotor assembly according to an embodiment of the present invention can be mounted. Although this particular image shows an onshore wind turbine, it will be understood that similar features are also found in offshore wind turbines. Further, although the wind turbine is described as having a "horizontal axis", for practical purposes, those skilled in the art will understand that the axis is usually slightly inclined to prevent contact between the blades and the wind turbine tower during strong winds.

[0017] The wind turbine 1 includes a tower 2, a nacelle 4 rotatably coupled to the top of the tower 2 by a yaw system, a rotor hub 8 attached to the nacelle 4, and a plurality of wind turbine blades 10 coupled to the rotor hub 8. The nacelle 4 and the blades 10 are rotated by the yaw system and oriented in the direction of the wind.

[0018] The nacelle 4 houses many functional components of the wind turbine, including a generator, a speed increaser, a rotor brake assembly, and a converter device that converts the mechanical energy of the wind into electrical energy for supply to the power grid. FIG. 2 shows an example of the layout within the nacelle 4, which layout includes a main shaft 26 extending through a main body bearing housing 20, a speed increaser 22, and a generator 24. The main shaft 26 is connected to the rotor 8 and driven by the rotor 8 to supply an input drive to the speed increaser 22. Collectively, these components can be considered the drive train of the wind turbine. The speed increaser 22 increases the rotational speed of the low-speed main shaft via internal gears (not shown) and drives the speed increaser output shaft. The speed increaser output shaft drives the generator 24, and the generator 24 converts the rotation of the speed increaser output shaft into electricity. The electricity generated by the generator 24 may be converted by other components (not shown) as necessary and then supplied to an appropriate consumer, such as a power grid distribution system.

[0019] The speed increaser 22 and the generator 24 may be coupled to each other as an integrated unit. FIG. 3 shows the generator 24 in more detail. First, referring to the speed increaser 22, the speed increaser housing is generally cylindrical since the specific type of speed increaser used in the illustrated embodiment is an epicyclic gear speed increaser. As is known to those skilled in the art, an epicyclic gear speed increaser includes a series of planet gears arranged around a central sun gear, and these planet gears are collectively arranged within an internal gear that surrounds them. The general configuration of the speed increaser is such that the input shaft and the output shaft are arranged on a common axis. The tooth number ratio between the internal gear, the planet gears, and the sun gear determines the gear ratio of the speed increaser. For clarity, the details of the speed increaser are not the main subject of the present invention and will not be described in more detail here. Other speed increasing mechanisms can also be used, but currently, the epicyclic gear speed increaser is considered to provide an elegant solution that fits within the scope of a wind turbine nacelle. Such an epicyclic gear speed increaser can include multiple planet gear stages, such as one, two, or three planet gear stages, for example.

[0020] Continuing to refer to the cutaway view of FIG. 3 and also referring to FIGS. 4 and 5, the generator 24 is an IPM (Interior Permanent Magnet) electrical machine having an external stator assembly 30 that surrounds an internal rotor assembly 32. The stator assembly 30 includes a stator winding 38, a stator core 40, and a stator frame (not shown) that surrounds and supports the stator winding 38 and the stator core 40. However, it should be noted that the present invention is not limited to a specific type of stator. In particular, the internal configuration of the generator 24 shown in FIG. 3 is provided here as an example and is provided to give an appropriate background to the present invention. The specific configuration of the generator rotor 32 in FIGS. 3 to 5 does not form part of the present invention and is provided to better understand the configuration of the generator rotor according to an embodiment of the present invention, as will be described later with reference to FIGS. 6 to 11.

[0021] The speed increaser 22 is coupled to the generator 24 via an output shaft 31 connected to the rotor assembly 32 of the generator 24. Thus, the long axis of the speed increaser output shaft 31 defines the rotation axis of the generator 24. Notably, the speed increaser also includes an input shaft 33 aligned coaxially with the speed increaser output shaft 31. The generator rotor assembly 32 is connected to the generator. 24 Inside Installed state It is shown in cross-section in Figure 3, but is shown isolated in Figures 4 and 5.

[0022] The generator rotor assembly 32 has a drive end 34 and a non-drive end 36. The drive end 34 faces the speed increaser 22, and the non-drive end 36 faces away from the speed increaser 22. The non-drive end 36 of the generator rotor assembly 32 is shown in Figure 4, and the drive end 34 of the generator rotor assembly 32 is shown in Figure 5.

[0023] The generator rotor assembly 32 includes a cylindrical annular structure 40 that defines a hollow central region and is arranged to rotate around a rotation axis. The cylindrical annular structure 40 includes a plurality of solid circular rotor rods 42 that house permanent magnet packages. Thus, the annular structure 40 plays a role in generating the rotating magnetic field of the generator when in use. Here, the rods 42 are shown as having equal circumference and thickness, but this can be modified. The rods 42 are arranged coaxially around the rotation axis, and when assembled, the arrangement of the rods 42 is such that it forms a cylindrical structure with a hollow region in the center. The rods 42 are arranged at equal intervals such that a gap is defined between each pair of rods 42. These gaps allow air supplied to the center of the generator to flow through the rotor structure and cool the generator rotor assembly and other parts of the generator, including the portion located radially outward of the rotor assembly 32. This airflow is further enhanced by the fact that a central hub is not required to provide the structure and support of the rotor assembly 32.

[0024] The cylindrical annular structure 40 is connected to the rotor support frame 50. The rotor support frame 50 has a radially outward first connecting flange 52, best shown in Figure 4, and a radially inward second connecting flange 54, best shown in Figure 5. The first connecting flange 52 serves to connect the rod 42 to the rotor support frame 50 and can therefore be considered a "rotor connecting flange," while the second connecting flange 54 serves to connect the rotor support frame 50 to the speed increaser output shaft 31 and can therefore be considered a "speed increaser connecting flange." In Figure 5, a pair of connecting bolts 56 used to fix the support frame 50 to the speed increaser output shaft 31 can be seen extending perpendicularly from the second connecting flange 54.

[0025] The support frame 50 and the cylindrical annular structure 40 are connected to each other by a number of tie rods 58 (only two of which are reference numerald in Figures 4 and 5), which extend axially through their respective holes in the rods 42 and are fixed through the rotor connection flanges 52 of the support frame 50. Appropriate mechanical fasteners, such as bolts, are provided at the ends of each tie rod 58 and are tightened to compress the package of rods 42, thereby firmly fixing the cylindrical annular structure 40 to the support frame 50 as a single unit.

[0026] Note that the rotor connection flange 52 and the speed increaser connection flange 54 are axially oriented surfaces that extend within their respective planes, which are parallel to each other but spaced apart along the rotor axis. In this regard, the speed increaser connection flange 54 extends somewhat within a hollow internal region defined by the cylindrical annular structure. Furthermore, the circumference of the speed increaser connection flange 54 is smaller than that of the rotor connection flange 52.

[0027] The support frame 50 further includes a transition section 60 extending between the rotor connection flange 52 and the speed increaser connection flange 54. The transition section 60 is generally truncated cone-shaped and extends at a steep angle with respect to the rotor axis. As shown here, the transition section 60 defines an angle of approximately 70 to 80 degrees with respect to the rotor axis. In other words, the transition section 60 has a cone angle of approximately 140 to 160 degrees.

[0028] Once the generator is assembled, the generator rotor assembly 32 is surrounded by the external stator 30. Next, both the rotor assembly 32 and the stator 30 are surrounded by the generator housing, or cabinet 68, which is best understood from Figure 3.

[0029] Regarding the known configuration of the generator rotor assembly 32 as described above, it should be understood that while this configuration offers various advantages in terms of generator design and efficiency, it also presents challenges. For example, limited access to the inside of the generator poses a problem when a mechanic needs to access the inside of the generator to inspect internal components and take necessary repair measures.

[0030] Embodiments of the present invention include improved configurations of generator rotor assemblies that address these problems. Embodiments of the present invention will be described below with reference to the remaining drawings.

[0031] The illustrated embodiment provides a generator rotor assembly 70 that is functionally equivalent to the known configuration of the generator rotor assembly 32 described above. However, embodiments of the present invention provide several advantageous aspects, which will be described in more detail in this discussion.

[0032] Figure 6 shows a partial schematic diagram of the generator rotor assembly 70 in relation to the components surrounding the generator housing, or "cabinet" 81, while Figures 7 to 9 show the generator rotor assembly 70 separated from the generator cabinet 81. At this point, it should be noted that the generator rotor assembly 70 of the illustrated embodiment shares many similarities with the one described earlier, so here we will focus only on the differences.

[0033] Broadly speaking, the generator rotor assembly 70 includes a rotor support frame 72 that supports a cylindrical field structure 74, which acts as a magnet carrier to generate a rotating magnetic field during operation. The configuration of the cylindrical field structure 74 is equivalent to that described with reference to Figures 3 to 5, so further detailed description of this assembly is omitted.

[0034] The generator rotor assembly 70 includes a drive end 76 and a non-drive end 78. The drive end 76 is connectable to the output drive shaft 77 of the speed increaser 22, and the non-drive end 78 is distal to the speed increaser 22. In effect, the generator rotor assembly 70 can be considered rotatably suspended from the speed increaser output shaft 77 in a cantilevered manner, since the non-drive end is not rotatably supported by a bearing.

[0035] Essentially, the rotor support frame 72 provides a means for connecting the speed increaser output shaft 77 to the cylindrical field structure 74. For this purpose, the rotor support frame 72 includes a speed increaser connecting flange 80 and a rotor connecting flange 82.

[0036] The speed increaser connecting flange 80 and the rotor connecting flange 82 are both oriented perpendicular to the rotation axis R of the generator rotor assembly 70, spaced apart from each other along that axis, and have axially oriented surfaces. Thus, in the illustrated embodiment, both flanges 80 and 82 extend in a plane perpendicular to the rotation axis R.

[0037] The speed increaser connection flange 80 is provided with an annular fixed slot configuration 84, through which the rotor support frame 72 It can be connected to the speed increaser output shaft 77 by a set of suitable bolts (not shown). Therefore, the fixed slot configuration 84 is shown in Figure 6 The diameter of the first pitch circle, indicated as "D1", is defined.

[0038] The rotor connection flange 82 is coaxial with the speed increaser connection flange 80 and has a larger diameter. The rotor connection flange 82 is fixed to the cylindrical field structure 74 by a tie rod system 86 comprising a plurality of circumferentially spaced tie rods 88 extending through the individual rods of the cylindrical field structure 74, as in the embodiments described above. Thus, the circular arrangement of tie rods 88 defines a second pitch circle diameter, shown as D2 in Figure 6. As shown, the first pitch circle diameter is smaller than the second pitch circle diameter D2. In the illustrated embodiment, the first pitch circle diameter D1 is second This is approximately 30% of the pitch circle diameter D2.

[0039] Conveniently, the tie rod system 86 includes balancing means for adjusting the rotational balance of the cylindrical field structure 74. The balancing means can be achieved by adding shims or washers that are trapped between the rotor connection flange 82 and the tie rod fasteners 89, such as hexagonal nuts. The tension of the tie rods 88 can be achieved by appropriately rotating each fastener 89 that applies a compressive force to the cylindrical structure 74, while the adjustment of the rotational balance can be achieved by adding or removing balance shims around the array of tie rods 88 until the optimal rotational balance is obtained.

[0040] The transition section 90 extends between the speed increaser connection flange 80 and the rotor connection flange 82. The function of the transition section 90 is to provide rigidity to the rotor support frame 72 while maintaining a distance between the rotor connection flange 82 and the speed increaser connection flange 80, thereby promoting good airflow through the structure.

[0041] As can be easily understood from the figure, the transition section 90 includes two main parts: a first truncated conical section 92 and a second axially oriented surface section 94. The truncated conical section 92 is close to the rotor connection flange 82, and the axially oriented surface section 94 is close to the speed increaser connection flange 80.

[0042] The truncated cone portion 92 includes several regions 96 (not all of which are shown in the figure for clarity), and these regions 96 are relatively flat because they are oriented at a shallow angle to the axis of rotation. Each region 96 extends axially at a relatively shallow angle to the axis of rotation, providing a suitable area for supporting a mechanic within the rotor support frame 72. Thus, each region 96 can be considered a step region. In the illustrated embodiment, there are a total of nine step regions 96.

[0043] Each step area 96 is distinguished from its adjacent area by a reinforcing rib, i.e., a web 98. The reinforcing rib 98 contributes to the rigidity of the transition area. Here, the step area 96 is embodied as a relatively thin plate-like portion.

[0044] In this regard, although the illustrated embodiment includes multiple step regions 96, this is not mandatory, and it should be understood that the transition section 90 can define any number of step regions, including only a single continuous step region that defines a curved surface extending circumferentially around the transition section 90 without substantially interruption.

[0045] As seen in Figure 11, the step area 96 provides a beneficially stable surface, i.e., a platform, which is flat enough to support a mechanic inside the interior chamber 97, enclosed by the rotor support frame 72 and therefore also by the generator cabinet 81. This aspect also benefits from various other aspects of the rotor support frame, particularly its internal dimensions. For example, the inner diameter of the rotor connection flange is greater than 1.8 m, but can be greater than 2.0 m, and even greater than 2.2 m. This provides adequate headroom for the mechanic inside the rotor support frame 72. This aspect can be further understood by observing the transition section 60 in Figures 3 to 5, which defines a much steeper angle with respect to the axis of rotation and limits the size of the space inside the rotor assembly. Furthermore, the steep surface provided by the transition section 60 prevents the mechanic from standing comfortably or safely.

[0046] A further advantage of the rotor support frame 72 is the axial dimension between the rotor connection flange 82 and the speed increaser connection flange 80. In the illustrated embodiment, the dimension labeled "A" (see Figure 6) indicates the length along the axis of rotation between the rotor connection flange 82 and the speed increaser connection flange 80. Dimension A is preferably greater than 0.5 m to give the internal chamber 97 of the rotor support frame 72 a useful "depth" to fully accommodate maintenance personnel inside. More preferably, dimension A is greater than 0.6 m.

[0047] The depth of the internal chamber 97 of the rotor support frame 72 is also benefited by the shallow angle of the step area 96. As can be seen in Figure 6, the step area 96 defines an angle of less than 30 degrees with respect to a line parallel to the axis of rotation. This angle is indicated as "B" in Figure 6. In other words, the portion of the transition section 90 defines a conical angle of less than 60 degrees. The shallow angle defined by the truncated cone portion with respect to the rotor axis R contributes to the depth of the internal chamber 97 of the cylindrical field structure 74.

[0048] As mentioned above, rotor support frame 72 The internal dimensions of the internal volume 97, both its inner diameter and depth "A", allow a mechanic to climb inside and access various parts of the generator and other components related to it. This is a significant advantage as it means the maintainability of the generator is considerably improved.

[0049] In addition to defining the step area 96, the transition section 90 further includes an axially oriented surface portion 94. The axially oriented surface portion 94 defines the drive end 76 of the transition section 90 such that the outer surface of the transition section 90 is rotated by approximately 90 degrees to provide a flat end face substantially perpendicular to the axis of rotation R. Advantageously, the reinforcing rib 98 extends along the step area 96 in a direction aligned with the axis of rotation and spreads between the step area 96 and the axially oriented surface portion 94.

[0050] The axially oriented surface portion 94 is provided with a series of access openings 100 that penetrate the depth of the axially oriented surface portion 94.

[0051] In this embodiment, the access openings 100 are arranged in a circular pattern and are equally spaced at angles. In the illustrated embodiment, there are a total of nine access openings 100, arranged in a configuration of one per step area 96. The circular arrangement of access openings 100 lies radially inward of the step area 96 and radially outward of the speed increaser connection flange 80. In this sense, it can be considered to be radially positioned between the speed increaser connection flange 80 and the step area 96.

[0052] The access openings 100 allow access through the rotor support frame 72, enabling a mechanic to perform a series of tasks such as monitoring components of the speed increaser output shaft, including bearing sensors (temperature sensors and accelerometers) and rotary encoders. For this purpose, the access openings should have a cross-sectional area that allows a mechanic to reach through one of the openings and touch as much as necessary. For this purpose, each of the access openings should have a cross-sectional area of ​​at least 100 cm². 2 It is assumed that an opening area of ​​at least 200 cm should be provided. Larger sizes are possible if necessary, at least 200 cm. 2 This has the advantage of providing a larger reach-through area and improving visibility through the opening.

[0053] Rotor support frame 72Although it functions as a single component connecting the speed increaser output shaft and the cylindrical field structure 74 and transmitting drive, in the illustrated embodiment, conveniently, the rotor support frame 72 includes at least first and second components, indicated herein by 102 and 104, respectively. If necessary, the components may be cast from, for example, a suitable grade of steel. The first component 102 is radially inward of the second component, and both components together function as hubs of the cylindrical field structure 74. Thus, the first component 102 can be considered an "inner hub component" 102, and therefore, the second component 104 can be considered an "outer hub component" 104.

[0054] As can be seen from the figure, the speed increaser connecting flange 80 is part of the inner hub component 102 and is separate from the outer hub component 104 that defines the transition section 90 and the rotor connecting flange 82. The two components 102 and 104 are connected by a circular arrangement of bolts 106 located radially outside the access opening 100. Notably, the circular arrangement 106 has a pitch circle diameter labeled D3 in Figure 6. The pitch circle diameter D3 of the circular arrangement 106 is larger than the pitch circle diameter D1 of the fixed arrangement 84. Manufacturing the rotor support frame 72 from at least two components in this way offers manufacturing advantages. Furthermore, this structure allows for convenient access to components related to the generator. For example, the inner hub component 102 can be disassembled from the rotor support frame 72 while the rotor assembly 70 is locked against rotational and radial motion. Therefore, the inner hub component 102 can be removed from the speed increaser by removing the circular arrangement 84 of bolts that connect the rotor support frame 72 to the speed increaser output shaft 77, thereby allowing access, maintenance, and removal / replacement of the bearing cassette (not shown) associated with the speed increaser 22 without requiring complete disassembly of the generator.

[0055] The rotor support frame 72 further comprises an extension portion 110. The extension portion 110 extends from the non-driven outer edge of the rotor connection flange 82 and is cylindrical in shape. The axial dimension of the extension portion 110 is approximately half the axial length of the cylindrical field structure 74. In the illustrated embodiment, the extension portion 110 is a thin-walled cylinder having a diameter approximately equal to the outer diameter of the rotor connection flange 82.

[0056] The non-driven end of the extension 110 also supports an internal gear 112 which engages with one or more drive motors 114. Here, the internal gear 112 is shown bolted to the extension 110 with a bolt ring 111. The internal gear 112 and drive motors 114 provide means to control the direction of rotation of the generator rotor assembly 70 during maintenance. For example, a mechanic may need to access a specific part of the generator that needs to be rotated to a particular position. The internal gear 112 and drive motors 114 also provide means to rotate the speed increaser and main shaft via the generator rotor assembly 70. Thus, it can be considered that the axial dimensions of the extension 110 are determined at least partially based on the required position of the internal gear 112. In the illustrated embodiment, the extension 110 also defines a plurality of airflow openings 115. The airflow openings 115 can take any shape in principle, but as shown here, there are a plurality of openings 115 distributed circumferentially around the extension 110, allowing air to flow radially outward. The airflow opening 115 can be configured to be completely open, or a perforated cover such as a grate can be provided to ensure that debris or loose parts do not pass through the opening 115. In addition to the airflow opening 115 defined in the extension 110, the rotor support frame 72 also includes a second set of airflow openings 116 (best shown in Figures 8 and 9) positioned radially inward compared to the first set of airflow openings 115. The second set of airflow openings 116 are distributed circumferentially around the transition section 90 and are arranged at equal angular intervals in this embodiment. More specifically, each opening 116 is defined in an elbow shape where the transition section 90 bends sharply into the rotor connection flange 82. Each opening 116 also features an associated guide groove 117 extending a short distance axially from the respective opening 116 along the transition section 90. The guide groove 117 is formed as a recess or notch on the surface of the transition section 90. The number of second airflow openings 116 is not important, but in the illustrated embodiment, there are two openings 116 for each step area 96. Note that the pair of second airflow openings 116 is located radially outward compared to the access opening 100.Both sets of openings 100 and 116 offer advantages in terms of airflow. However, positioning both sets of openings 100 and 116 at spaced radially apart promotes a more uniform flow of air through the rotor support frame.

[0057] The extension 110 is also fixed to the bolt ring 111 and thus supports a brake disc 118 located radially outward relative to the internal gear 112. The brake disc 118 is actuated by a pair of brake actuators 119, which are mounted on a generator repair and inspection cabinet 81, best shown in Figure 10.

[0058] From the above discussion, it will be understood that the various configurations of the generator rotor assembly in the illustrated embodiments enhance the maintainability of various components of the generator, particularly the generator rotor assembly. For example, the internal volume dimensions of the rotor support frame 72 mean that a mechanic can access the inside of the generator. This is useful for at least one of the following purposes: Firstly, 360-degree access is possible to the tie rod system 86, the associated tension nuts 89, and the balance adjustment mass 87, allowing a technician to make appropriate adjustments to these components around the entire circumference of the rotor support frame 72 while remaining in a single position inside the generator. This provides a significant advantage as adjustments can be made quickly without disassembling the machine. Furthermore, a technician inside the generator has 360-degree access to the circular arrangement of bolts 106 connecting the speed increaser connection flange 80 to the transition section 90, and also to the circular arrangement of bolts 84 connecting the rotor support frame 72 to the speed increaser output shaft. This allows for quick inspection of these bolted connections, which is a significant advantage during the maintenance process. Furthermore, as described above, this allows the removal of the inner hub component 102 to access the speed-increasing shaft 77, thereby enabling the removal and replacement of the bearing cassette. In addition, the large space inside the generator allows technicians 360-degree access to the bolted connection between the internal gear 112 and the extension 110. Similarly, the drive motor 114 that engages with the internal gear 112 is also accessible.In addition to the various components described and illustrated above, it should also be understood that the general configuration of the access opening 100 and the rotor support frame 72 facilitates access to other internal generator components, such as a radial rotor locking system provided to lock the rotor so that it does not move radially during maintenance, an axial rotor locking system provided to lock the rotor so that it does not move axially, a stray current protection system, a rotary encoder which may be provided on the speed increaser output shaft, other sensor systems such as accelerometers and temperature sensors which may be provided on the speed increaser output shaft and at other locations, a brake disc component provided to apply braking force to the rotor during maintenance, and a pitch tube seal component provided to provide a proper seal to a pitch tube component that extends through the center of the drive transmission assembly to supply hydraulic pressure and / or power to a hydraulic pitching system located within the rotor hub.

[0059] Overall, the configuration of the rotor support frame 72 provides a relatively open volume within it, which is of a size and shape advantageous for access by personnel who can perform various maintenance activities. Thus, it can be considered that the volume defines a maintenance room inside the generator, which is of a size and shape suitable for accommodating repair and inspection personnel. This is in contrast to known approaches in which access to various components is achieved only from outside the generator, or access from inside the generator is limited by the relative arrangement of internal components.

[0060] Advantageously, the open volume inside the generator rotor assembly 70 can be sealed to provide a more protective environment, while still allowing access for repair and inspection personnel when necessary. As shown in Figures 11a and 11b, a closing member 120, such as a door or hatch, may be provided on the rear of the generator repair and inspection cabinet 81. The closing member 120 may be a single door panel covering the opening 121 of the generator cabinet 81 to the interior chamber where the generator rotor assembly 70 is housed. Alternatively, the closing member 120 may comprise multiple panels. As shown in the figure, the closing member 120 comprises two door panels 122, 124. These door panels 122, 124 may be mounted in any suitable manner that allows for opening. For example, the door panels 122, 124 may be mounted by a fastening system that allows one or both panels to be lifted out of the cabinet opening when access to the inside of the generator is required. Alternatively, one or both of the door panels 122, 124 may remain connected to the generator repair and inspection cabinet 81 but be hinged to allow movement for access as needed. Figure 11b shows one door panel 124 having hinged fastenings, and it will be understood that the other door panel 122 may have similar fastenings.

[0061] Beneficial in this regard, the closing member 120 encloses the internal volume of the generator, meaning that the internal environment is isolated from the overall interior of the nacelle in which the generator is installed.

[0062] The closing member 120 achieves a further advantage in that it can provide a single maintenance inlet point to the internal volume of the generator for maintenance purposes. This means that a single safety mechanism can be implemented in the closing member to control access for maintenance. The safety mechanism can be a keypad, a finger scanner, or other access control technology. Preferably, access through the closing member is permitted only if the safety mechanism detects that one or more other safety means or interlocks have been addressed. For example, when the rotor is locked and stationary, the appropriate electrical systems are disabled, and there is no electrical risk associated with repair and inspection personnel accessing the inside of the generator.

[0063] The internal volume inside the generator is provided as a maintenance room with ample space, so this area can be designed as a dedicated workspace for accessing many of the structures and systems associated with the generator, as described above. For example, by installing a floor cover in the maintenance room, falling objects can be caught, thereby avoiding the risk of loose or detached parts being inside the generator. Furthermore, the enclosed environment of the maintenance room by the closing member 120 means that the areas accessible from the maintenance room can be kept as clean as possible, which is easier to achieve on a smaller scale than requiring the entire nacelle to be thoroughly cleaned.

[0064] Many modifications can be made to the specific embodiments described above without departing from the scope of the invention as set forth in the attached claims. Features of one embodiment can also be used in other embodiments, either as additions or substitutions to such embodiments.

Claims

1. In a wind turbine drive transmission assembly including a speed increaser (22) connected to a generator (24) for a wind turbine, The generator (24) comprises a stator (38) located radially outward and a rotor (70) located radially inward, the rotor comprises a cylindrical field structure (74) configured to rotate about the generator rotor axis (R), and the rotor is configured to define a central hollow portion. The rotor further comprises a rotor support frame (72) connected to the cylindrical field structure and structurally supporting the cylindrical field structure. The rotor support frame is, A rotor connection flange (82) for attaching the rotor support frame to the cylindrical field structure, The rotor support frame is connected to the output drive shaft (77) of the speed increaser by a speed increaser connection flange (80), A transition portion (90) extending between the rotor connection flange (82) and the speed increaser connection flange (80), Equipped with, The wind turbine drive transmission assembly wherein the transition section (90) is at least partially defined by one or more step regions (96), and one step region (96) or each step region (96) is formed to define a surface inclined at an angle of less than 30 degrees with respect to the rotor axis.

2. The wind turbine drive transmission assembly according to claim 1, wherein the one step area (96) or each of the step areas (96) provides a step surface that extends circumferentially around the rotor axis.

3. The wind turbine drive transmission assembly according to claim 1 or 2, comprising a plurality of separate step areas (96).

4. The wind turbine drive transmission assembly according to claim 3, wherein the plurality of separate step areas (96) are separated by their respective reinforcing ribs (98).

5. The wind turbine drive transmission assembly according to any one of claims 1 to 4, wherein the transition portion (90) further includes an end face (94) oriented in the axial direction.

6. The wind turbine drive transmission assembly according to claim 5, wherein the axially oriented end face (94) is substantially aligned with the speed increaser connecting flange (80) along the direction of the rotor axis (R).

7. The wind turbine drive transmission assembly according to claim 5 or 6, wherein the one or more step areas (96) are arranged along the direction of the rotor axis (R) between the axially oriented end face (94) and the rotor connecting flange (82).

8. The wind turbine drive transmission assembly according to any one of claims 5 to 7, wherein the axially oriented end face (94) includes a plurality of access openings (100).

9. The wind turbine drive transmission assembly according to claim 8, wherein each of the plurality of access openings (100) has an opening area of ​​at least 100 cm².

10. The wind turbine drive transmission assembly according to claim 8, wherein each of the plurality of access openings (100) has an opening area of ​​at least 200 cm².

11. The wind turbine drive transmission assembly according to any one of claims 1 to 10, wherein the distance (A) along the rotation axis between the speed increaser connecting flange (80) and the rotor connecting flange (82) is 20% to 60% of the inner diameter of the rotor connecting flange (82).

12. The wind turbine drive transmission assembly according to any one of claims 1 to 10, wherein the distance (A) along the rotation axis between the speed increaser connecting flange (80) and the rotor connecting flange (82) is 20% to 40% of the inner diameter of the rotor connecting flange (82).

13. The wind turbine drive transmission assembly according to any one of claims 1 to 12, wherein the rotor connection flange (82) and the transition portion (90) form a first integrated component (104).

14. The wind turbine drive transmission assembly according to claim 13, wherein the first integral part (104) is mechanically connected to the speed increaser connecting flange (80) by a bolt ring (106) radially inward of the axial end face (94).

15. The wind turbine drive transmission assembly according to any one of claims 1 to 14, further comprising a generator repair and inspection cabinet (81) for housing the rotor (70).

16. The wind turbine drive transmission assembly according to claim 15, wherein the generator repair and inspection cabinet (81) is connected to the speed increaser housing.

17. The wind turbine drive transmission assembly according to claim 15 or 16, wherein the generator repair and inspection cabinet (81) defines an internal chamber for housing the rotor (70), and the generator repair and inspection cabinet (81) comprises one or more closing elements (122, 124) configured to selectively close an opening (121) defined by the generator repair and inspection cabinet into the internal chamber.

18. The wind turbine drive transmission assembly according to any one of claims 1 to 17, wherein the speed increaser (22) includes at least one planetary gear stage.

19. A wind turbine comprising a wind turbine drive transmission assembly according to any one of claims 1 to 18.

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