Gearbox for a wind turbine

Abstract

A transmission for a wind turbine comprises a gearbox having a drive output side, a generator having a drive input side, a drive shaft extending between the drive output side and the drive input side and defining an axis of rotation. In use, torque is transmitted through the drive shaft from the drive output side to the drive input side. The transmission further comprises a torque bypass arrangement associated with the drive shaft, wherein the torque bypass arrangement is configured such that, in use, in the event of a mechanical failure of the drive shaft, torque is transmitted from the drive output side of the gearbox to the drive input side of the generator by the torque bypass arrangement. One benefit of the transmission is that the torque bypass arrangement acts as a failsafe mechanism in the event of a failure of the drive shaft which impairs its ability to transmit torque between the input and output ends.

Description

Technical Field

[0001] This invention relates to a transmission device that is particularly useful in the context of wind turbine generators. Background Technology

[0002] A typical horizontal axis wind turbine (HAWT) consists of a tower, a nacelle at the top of the tower, a rotor hub mounted to the nacelle, and a set (usually three) of wind turbine rotor blades connected to the rotor hub. Depending on the wind direction, the nacelle and rotor blades are rotated and guided to the optimal direction by a yaw system for rotating the nacelle and a pitch system for rotating the blades.

[0003] The nacelle houses many of the wind turbine's functional components, including a generator, gearbox, and rotor braking assembly, as well as converters that convert the mechanical energy at the rotor into electrical energy for transmission to the power grid. The gearbox increases the speed of the low-speed main shaft and drives the gearbox output shaft. The gearbox output shaft, in turn, drives the generator, which converts the rotation of the gearbox output shaft into electricity. The electricity generated by the generator can then be converted as needed and supplied to appropriate consumers, such as the power grid distribution system.

[0004] The gearbox output shaft is known to be a single point of failure. Typically, gearbox output shafts are made of high-strength machined steel. However, recent advancements have revealed the manufacture of gearbox output shafts, or at least portions thereof, from composite materials. This can benefit the reduction of noise from rotating parts of the gearbox and generator, as composite components can be manufactured with greater flexibility than steel components, thus altering the sound characteristics.

[0005] It is against this backdrop that the example of the present invention was designed. Summary of the Invention

[0006] According to a first aspect of the invention, a transmission device for a wind turbine is provided, the transmission device comprising a gearbox having a drive output side, a generator having a drive input side, and a drive shaft extending between the drive output side and the drive input side and defining a rotation axis. In use, torque is transmitted from the drive output side to the drive input side via the drive shaft. The transmission device further includes a torque bypass device associated with the drive shaft, wherein the torque bypass device is configured such that, in use, in the event of a mechanical failure of the drive shaft, torque is transmitted from the drive output side of the gearbox to the drive input side of the generator via the torque bypass device.

[0007] One advantage of the transmission is that the torque bypass device acts as a fail-safe mechanism when the drive shaft experiences a failure event that impairs its ability to transmit torque between the input and output ends. In such an event, the torque bypass device becomes active to ensure the continuation of torque transmission. Examples of the invention are particularly advantageous for drive shafts with some composite material construction. Drive shafts with composite material construction offer some advantages in terms of increased flexibility, which can reduce noise. However, composite components are generally known to have more unpredictable failure characteristics compared to their steel equivalents. Therefore, the torque bypass device of the present invention can provide a backup means of torque transmission in the event of a drive shaft failure. Furthermore, the torque bypass device can be configured such that, in addition to the torque transmitted along the drive shaft itself, it also activates to transmit torque between the drive output side of the gearbox and the drive input side of the generator. This may be the case where the drive shaft has sufficient flexibility to allow a certain amount of torsional movement along the drive shaft during use (e.g., under heavy load conditions). However, it may be necessary to limit the amount of torsional movement that occurs. In this case, the torque bypass device can be configured such that when there is a relative angular movement between the input and output ends of the drive shaft exceeding a predetermined angular range, torque can be transmitted along the load path defined by the torque bypass device. In other words, if there is excessive torsional motion on the drive shaft, torque can be transmitted along the load path defined by the torque bypass device.

[0008] Further optional and advantageous features are provided in the dependent claims.

[0009] In another aspect, an example of the present invention provides a wind turbine including the transmission device described above. Attached Figure Description

[0010] The invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 This is a schematic diagram of a typical wind turbine, showing the main functional components housed within the wind turbine nacelle; Figure 2 This is an example view of a drive shaft for a wind turbine, used to connect a gearbox and a generator, wherein the drive shaft is equipped with a torque bypass device. Figure 3 and Figure 4 yes Figure 2 The schematic diagram of the drive shaft shows the torque bypass device operating in "normal" and "fault" states, respectively. Figure 5 and Figure 6a , Figure 6b Other examples of torque bypass devices are shown; Figure 7This is another example view of the drive shaft of a wind turbine with a torque bypass device; Figure 8 This is another example view of a drive shaft and associated torque bypass device, where the drive shaft is shown connected between the gearbox and the generator rotor; Figure 9 Is it through Figure 8 A partial cross-sectional view showing the torque bypass device; Figure 10 and Figure 11 It is similar to Figure 9 A simplified view of a further example of the present invention. Detailed Implementation

[0011] Specific examples of the invention will now be described, in which many features will be discussed in detail to provide a thorough understanding of the inventive concept defined in the claims. However, it will be apparent to those skilled in the art that the invention can be practiced without specific details, and in some cases, well-known methods, techniques, and structures have not been described in detail in order to unnecessarily obscure the invention.

[0012] In order to place the examples of the present invention in a suitable context, references will first be made to... Figure 1 , Figure 1 A typical horizontal-axis wind turbine (HAWT) 1 is shown, which can implement a drive mechanism according to an example of the invention. Although the wind turbine 1 is referred to as "horizontal-axis," those skilled in the art will understand that, for practical purposes, the axis is typically slightly inclined to prevent contact between the rotor blades and the wind turbine tower in strong winds. Examples of the invention are considered applicable to other types of wind turbines, such as vertical-axis machines. Furthermore, examples of the invention are considered applicable to other types of renewable energy generators using similar drive mechanisms, including water turbines.

[0013] The wind turbine 1 includes a tower 2, a nacelle 4 rotatably connected to the top of the tower 2 via a yaw system 6, a rotor hub 8 mounted to the nacelle 4, and multiple wind turbine rotor blades 10 connected to the rotor hub 8. The nacelle 4 and the rotor blades 10 are rotated by the yaw system 6 and guided into the wind direction.

[0014] The nacelle 4 houses many of the functional components of the wind turbine, including the gearbox 12, the generator 14, and the power converter system 16 for converting the mechanical energy of the wind into electrical energy for transmission to the power grid.

[0015] Gearbox 12 is driven by a low-speed main shaft 20, which is coupled to rotor hub 8 and extends into nacelle 4. Main shaft 20 is supported on suitable bearings (not shown). Main shaft 20 is driven by rotor hub 8 and provides input drive to gearbox 12. Gearbox 12 increases the rotational speed of low-speed main shaft 20 via internal gears (not shown) and drives high-speed drive shaft 22. Drive shaft 22, in turn, drives generator 14, which converts the rotation of drive shaft 22 into electricity. The electricity generated by generator 14 is then converted as needed by power converter system 16 and supplied to appropriate consumers (e.g., the power grid) via suitable conductor 26. Therefore, gearbox 12, drive shaft 22, and generator 14 constitute the transmission for wind turbine 1.

[0016] In some arrangements, gearbox 12 and generator 14 can be connected together as an integrated unit. However, in these cases, a drive shaft still exists to provide the connection between the high-speed output side of gearbox 12 and the input side of generator 14.

[0017] Gearbox 12 can be constructed in various ways. For example, a conventional "parallel shaft" gearbox can be used in some applications where the input and output shafts of the gearbox are in a common plane and parallel to each other. Another type of gearbox to which this invention is applicable is a planetary or revolute gearbox. As those skilled in the art know, a planetary gearbox comprises a series of planetary gears arranged around a central sun gear, and these planetary gears are collectively arranged within a surrounding ring gear. The ratio of the number of teeth between the ring gear, planetary gears, and sun gear determines the gear ratio of the gearbox. For clarity, the details of the gearbox will not be described further here, as the gearbox is not the main subject of this invention. Other gearbox constructions may also be used, although the planetary gearbox is currently envisioned as providing an elegant solution to the constraints of wind turbine nacelles.

[0018] Although drive shaft 22 is Figure 1 It is shown in schematic form, but Figure 2 The examples are shown in more detail below.

[0019] The drive shaft 22 is generally cylindrical, like a typical drive shaft, and is configured to connect the drive output side of the gearbox 12 and the drive input side of the generator 14. For this purpose, the drive shaft 22 extends along the longitudinal / rotational axis X between the first end 30 and the second end 32.

[0020] The first end 30 of the drive shaft 22 is provided with a first fastener 34, and the second end 32 is provided with a second fastener 36. In this example, both fasteners 34 and 36 are shown as flanges, although those skilled in the art will understand that other fasteners, such as splined shafts, universal joints, and other couplings, can be used. The fasteners 34 and 36, as flanges, are provided with a circular array of holes 38, which serve as bolt connection points when assembling the drive shaft 22 to adjacent drive components. For example, fastener 34 will be connected to the drive output side of the gearbox 12, and fastener 36 will be connected to the drive input side of the generator 12.

[0021] The drive shaft 22 can be solid or hollow. Furthermore, it can be made of different materials. Typically, drive shafts in this field are made of high-strength steel alloys, although other metallic materials are of course acceptable, provided they possess the necessary material properties for the specific application.

[0022] Drive shafts for wind turbine applications are also known to be made of composite materials. For example, drive shafts can be formed from carbon composites, where carbon fibers are encapsulated in a resin matrix. Such composites are generally known in the art and therefore will not be discussed in detail here. However, composites in this context can offer some advantageous properties, such as a higher strength-to-weight ratio and increased torsional flexibility compared to steel, but they can also provide beneficial variations in emitted noise characteristics. Furthermore, composites used in the context of drive shafts can provide some electrical isolation, which can be beneficial.

[0023] At least a portion of the drive shaft 22 in the illustrated example may be formed of a composite material. For example, the cylindrical section of the drive shaft extending between the first retainer 34 and the second retainer 36 may be a composite material, while the first retainer 34 and the second retainer 36 may be made of metal (e.g., steel) to provide a robust bolted connection. In other examples, substantially the entire drive shaft 22 may be formed of a composite material, including the end retainers 34, 36.

[0024] In other examples, drive shaft 22 may be integrated with the output side of gearbox 12 and / or with the input side of generator 14. That is, end fasteners 34, 36 may form integral parts of the respective rotating components of gearbox 12 and generator 14, rather than being connected to specific input / output components of generator and gearbox.

[0025] The drive shaft 22 is provided with a torque bypass device 40. The function of the torque bypass device 40 is to act as a fail-safe device in the event that the drive shaft 22 experiences a mechanical failure between the first end 30 and the second end 32 during use, making it unable to transmit torque along the longitudinal range of the drive shaft 22. For example, the drive shaft 22 may develop a circumferential crack during use, making it unable to transmit the torque generated at the first end retainer 34 on the output side of the gearbox 12 to the second end retainer 36 on the input side of the generator 14.

[0026] In the event of such a mechanical failure in drive shaft 22, torque bypass device 40 can be operated to transfer torque from the drive output side of gearbox 12 to the drive input side of generator 14.

[0027] like Figure 2 As shown, the torque bypass device 40 includes a torque transmission member 42 and a torque receiving member 44. The torque transmission member 42 and the torque receiving member 44 are configured such that torque can only be transmitted between them in the event of a mechanical failure of the drive shaft 22.

[0028] from Figure 2 It is understood that the torque transmission member 42 includes a body 46 from which a plurality of torque arms 48 extend. In this example, there are six (6) torque arms 48 extending in a direction aligned with and in this case parallel to the longitudinal axis X. In this example, the body 46 is disc-shaped with a circular outer contour, but this is not required. Furthermore, in this example, the torque arms 48 are integral with the body 46, but again, this is merely for illustrative purposes and should be understood that this configuration is not necessary.

[0029] The torque arm 48 engages with the torque receiving member 44. Here, the torque receiving member 44 includes a body 50, which is also disc-shaped, similar to the body 46 of the torque transmitting member 42.

[0030] In the example shown, the torque arm 48 is received at its end 52 into a corresponding socket 54 of the torque receiving member 44 and engages with the body 50 of the torque receiving member 44.

[0031] In the example shown, the socket 54 is a hole formed to define a gap or void C between the outer surface of the corresponding torque arm 48 and the inner surface of the socket 54. This can be seen from... Figure 2As seen in the inset partial view, the circular end 52 of one of the torque arms 48 is received into a similarly shaped socket 54. The socket 54 has a larger diameter than the end 52 of the torque arm 48 to define a gap C. The purpose of the gap C is to allow some relative movement between the torque transmitting member 42 and the torque receiving member 44 without transmitting torque between these components. Therefore, the gap C is used to accommodate torsional deflection of the drive shaft in the section between the torque transmitting member 42 and the torque receiving member 44. Typically, this will be high-frequency relative movement, which could otherwise lead to noise. Furthermore, in the context of wind turbines, significant torque reversal may occur in the drive shaft due to variable dynamic loads. Therefore, the gap C is used to ensure that the torque transmitting member 42 and the torque receiving member 44 do not contact each other during normal operation of the transmission.

[0032] Designing an acceptable gap between the torque transmission member 42 and the torque receiving member 44 is considered to be within the capabilities of those skilled in the art. As an example, the gap C may be configured to allow a small amount of angular movement between the torque transmission member 42 and the torque receiving member 44. The amount of allowed angular movement is not intended to be limiting, but may be at least 1 degree, for example, between 5 and 10 degrees. Thus, in the example above, the absolute value of the gap C may be a diameter gap (i.e., a diameter difference) of at least 1 mm, for example, approximately 10 mm to 20 mm, although it should be understood that these values ​​are not considered limiting.

[0033] In the event of a mechanical failure of the drive shaft 22 between the positions of the torque transmission member 42 and the torque receiving member 44, the torque input will still be applied to the torque transmission member 42, which will rotate relative to the torque receiving member 44 until the end 52 of the torque arm 48 engages with the socket 54. As a result, the torque transmission member 42 will move at an angle beyond the distance set by the gap C, so the torque will be transmitted indirectly between the ends of the drive shaft 22 via the torque bypass device 40 rather than directly along the length of the drive shaft 22 itself. It should be noted that in the illustrated example, the torque transmission member 42 and the torque receiving member 44 are connected to the drive shaft 22 at spaced-out positions, such that the torque bypass device 40 does not cover the entire length of the drive shaft 22, as shown. It should be understood that a longer length of the drive shaft 22 can be covered by the torque bypass device 40 with appropriate modifications. For example, Figure 2 The entire length of the drive shaft 22 shown can be spanned by designing the body 46 of the torque transmission member 42 closer to or integrated with the first end retainer 34 of the drive shaft 22, and similarly by designing the body 50 of the torque receiving member 44 closer to or integrated with the second end retainer 36 of the drive shaft 22.

[0034] Advantageously, the torque bypass device 40 can also be engaged in situations other than mechanical failure of the drive shaft, such as when the drive shaft is subjected to torsional deflection exceeding a predetermined amount. In this case, the torque will still be transmitted along the load path defined by the drive shaft, but the torque will also be transmitted along a second load path defined by the torque bypass device. Therefore, it will be understood that in this case, the torque bypass device 40 provides a torque limiting function for the drive shaft 22 to prevent the application of excessive torque that could lead to excessive wear of the material of the drive shaft 22.

[0035] This is due to Figure 3 and Figure 4 It is illustrated. Figure 3 The drive shaft 22 and associated torque bypass device 40 are shown in a "normal" operating state. In this context, "normal" means that the gearbox 12 and drive shaft 22 are operating as intended to transmit torque along the axis of rotation of drive shaft 22 from a first end 30 to a second end 32, while the torque transmission member 42 is not engaged with the torque receiving member 44, and therefore torque cannot be transmitted along that path. This is illustrated by an inset partial view, in which the end 52 of the torque arm 48 is shown spaced apart from the corresponding socket 54 of the torque receiving member 44.

[0036] In comparison, Figure 4 The diagram shows a drive shaft 22 in a "faulty" state and its associated torque bypass device 40. In this context, the faulty state is considered to exist at a point between the ends 30 and 32 of the drive shaft 22, and more specifically at the point between the axial positions of the torque transmission member 42 and the torque receiving member 44 connected to the drive shaft 22, indicating a mechanical failure of the drive shaft 22. In this figure, the torque bypass device 40 is activated such that the torque transmission member 42 engages with the torque receiving member 44, as shown in the inset partial view, where the end 52 of the torque arm 48 has been moved to the right to contact the socket 54.

[0037] In this respect, it should be noted that the torque transmission member 42 and the torque receiving member 44 can be connected to the drive shaft 22 in any suitable manner. This can be done by welding, or they can be bolted to the drive shaft via a suitable flange connection (not shown), which is merely an example.

[0038] exist Figure 3 In this configuration, the drive shaft 22 operates normally, thus transmitting torque along its length between its first end 30 and second end 22. It can be seen here, in the inset partial view, that the gap C is maintained between the end 52 of the torque arm 48 and the corresponding socket 54 of the torque receiving member 44.

[0039] exist Figure 4As can be seen, a break 'B' exists in the torque transmission path between the first end 30 and the second end 32 of the drive shaft 22. It should be noted that break B does not necessarily mean complete failure of the drive shaft 22 at a specific point, but can include significant structural weakening that impairs the torque transmission capability of the drive shaft 22. In either case, the driven end 30 of the drive shaft 22 is caused to move at an angle relative to the output end 32 about the longitudinal axis X. This means that the torque transmission member 42 also moves relative to the torque receiving member 44, meaning that the torque arm 48 abuts against the socket 54. This is in Figure 4 The embedded partial diagram shows that, as a result, torque is transmitted along the torque bypass device 40, thereby “bypassing” the break B in the drive shaft 22 between the coupling point of the torque transmission member 42 and the torque receiving member 44. It will thus be understood that, in the event of a severe failure of the drive shaft 22, the torque bypass device 40 provides an alternative path for torque transmission. This is particularly useful in systems where the rotor braking system engages with the transmission at a point further from the drive shaft or “downstream” (e.g., via a rotor brake disc integrated into the rotating components of the generator).

[0040] The above-mentioned torque bypass device 40 can be structurally modified to enhance its functionality.

[0041] The first variation is Figure 5 As shown in the figure. Here, a portion of the torque receiving member 44 is shown, similar to... Figure 3 and Figure 4 The inset partial view shows the torque arm 48 being received in its corresponding socket 54, thereby defining a gap C. In this example, the gap C accommodates an elastic bushing 60. The bushing 60 may be made of a relatively soft material, such as a polymer. In addition to or as an alternative to the examples described above, it should be understood that the geometry of the socket 54 and the associated protrusion 52, or equivalent components in other examples not shown, may be configured to plastically deform upon contact between them to result in controlled yielding. This can be combined with a suitable material selection, if appropriate. For example, the material of the torque receiving member may be chosen to be softer than the material of the torque transmitting member.

[0042] Bushing 60 provides a shock damper 62 for torque bypass device 40, which is used to mitigate the impact of torque transmission member 42 on torque receiving member 44 in the event of drive shaft 22 failure. The elastic characteristics of bushing 60 can be adjusted as needed to change the shock damping provided.

[0043] The alternative construction of the shock buffer 62 is in Figure 6a and Figure 6b As shown in the image. (To be consistent with...) Figure 5 In a similar way, Figure 6a and Figure 6bA view is provided showing the torque arm 48 receiving in its corresponding socket. However, Figure 6a The normal operating state of the drive shaft and torque bypass device 40 is shown, while Figure 6b The fault states are shown, and their definitions have been discussed above.

[0044] As can be seen, the socket 54 is not circular as in the previous embodiments, but is formed in a non-circular form, or more specifically, elliptical or oval. This is done so that when the torque arm 48 engages with the socket 54, a mutually inclined surface engagement is formed, which creates a wedging effect as the end of the torque arm moves laterally within the socket 54 and is pushed into the elongated, narrower end of the socket 54. Note that slight deformation of the torque arm 48 and the socket 54 in this area is allowed to achieve the wedging effect, thus providing the impact cushioning function discussed above. Other forms are also acceptable. For example, the socket 54 can have a straight form other than an ellipse, and the end of the torque arm 48 can also be straight. Furthermore, it is envisioned that the end 52 of the torque arm 48 may be provided with a central hollow portion or recess (not shown), which allows for a degree of plastic deformation of the end 52 of the torque arm 48 when it is forced to engage with the corresponding socket 54. Other arrangements providing similar functionality will also be envisioned by those skilled in the art.

[0045] Reference Figure 7 describe Figures 2 to 6b An alternative example of the drive shaft 22 and bypass device 40 shown, wherein the bypass device will be referred to as "140".

[0046] Figure 7 Bypass device 140 and Figures 2 to 6b The bypass device 40 has many similarities, so for the sake of brevity, only the differences will be described here.

[0047] exist Figure 7 In this configuration, the torque transmission member 142 and the torque receiving member 144 are connected to the drive shaft 22 as in the previous example, and are in disc form.

[0048] Multiple torque arms 148 are connected to the torque transmission member 142. The torque arms 148 can be integrally formed with the torque transmission member 142, such as... Figure 7 As shown, it can also be a separate component but fixed by appropriate technology.

[0049] In the example shown, there are four (4) torque arms 148 that extend from the torque transmission member 142 at equally spaced angular intervals. As shown, the torque arms 148 extend from circumferentially spaced positions around the torque transmission member 142.

[0050] As in the previous example, the end 152 of the torque arm 148 engages with a corresponding socket 154 provided at the torque receiving member 144. However, in this example, the socket 154 is provided as a recess defined around the circumferential edge of the torque receiving member 144. A gap C is defined between the end 152 of the torque arm 148 and the corresponding socket 154 to provide the same functionality as described.

[0051] The torque bypass device 140 is also provided with a support structure 160. The support structure 160 is configured to constrain the torque arm 148 to move in the radial direction relative to the longitudinal axis X.

[0052] The support structure 160 is shown herein as a structural member 162 that extends circumferentially and connects each torque arm 148. In this example, the structural member 162 is shown as integral with the torque arms 148, although this is not required. Other configurations are acceptable. For example, the structural member 162 may be in the form of a band or ring extending circumferentially around the outside of the torque arms 148. This ring may be independent of the torque arms 148 and secured to them by appropriate techniques, such as welding or by suitable mechanical fasteners such as bolts.

[0053] Now refer to Figure 8 and Figure 9 Further examples are described below. Due to the similarity to the previous examples, the same reference numerals will be used to refer to similar parts, but with the prefix "2".

[0054] exist Figure 8 In the diagram, gearbox 212 is shown attached to generator 214 via drive shaft 222.

[0055] Generator 214 is shown schematically, and its casing 215 is shown in dashed lines. Generator 214 is... Figure 8 The image is shown in cross-section.

[0056] Generator 214 includes a stator 224 and a rotor 226. The rotor 226 is supported to rotate within the range of the stator 224. In some examples, the rotational support of the rotor 226 may be provided by a gearbox 212, as shown here. Therefore, the rotor 226 can be considered to be cantilevered by the gearbox 212, as it is supported only at one end. In other examples, the rotor 226 may be supported at both ends.

[0057] The stator 224 includes a set of windings 228, as is conventional in generator structures. Similarly, the rotor 226 includes a generally cylindrical magnetic structure 227 that supports a set of magnetic elements (not shown). This configuration of the rotor thus enables the generation of a rotating magnetic field that interacts with the windings 228 to produce an electric current. This is conventional technology and will not be discussed further here for the sake of brevity. An example of such a generator is disclosed in Vestas Wind Systems A / S WO2020 / 143888.

[0058] The structure of rotor 226 can be described as a "hollow rotor" design because there is no drive shaft that runs through the internal space of the rotor. Instead, the cylindrical rotor 216 is supported only at one end by a support structure 229.

[0059] The support structure 229 has two ends. The first end, or “outer” end 230, connects to the circumferentially extending end of the magnetic structure or “ring” 227 and serves as a mounting point for the magnetic ring 227. The outer end 230 will henceforth be referred to as the “ring mount.” The second end, or “inner” end 232, provides a connecting hub 234 for the rotor 226. In this example, the connecting hub 234 is circular. The connecting hub 234 is located radially inward relative to the ring mount 230 of the support structure 229.

[0060] The body 246 of the support structure 229 extends between the hub 234 and the ring mount 230. The body 246 extends radially between the hub 234 and the ring mount 230. The precise form of the body 246 is not critical, as its primary function is to support the ring mount 230 in a fixed radial position relative to the hub 234. Therefore, the body 246 can be, for example, in the form of a solid disc or a set of spokes.

[0061] Drive shaft 222 is connected between gearbox 212 and generator 214. More specifically, drive shaft 222 is connected between the output side of gearbox 212 and the connecting hub 234 of generator 214.

[0062] The drive shaft 222 includes a first end 240 and a second end 242. The first end 240 is connected to the gearbox 212, while the second end 242 is connected to the connecting hub 234 of the generator 212.

[0063] The drive shaft 222 can be a conventional shaft, in the form of a monolithic cylindrical metal shaft (e.g., steel) extending between the first end 240 and the second end 242. The drive shaft 222 can also be a composite material construction as discussed above, such as carbon fiber composite, in a solid or more generally cylindrical form.

[0064] In the example shown, the drive shaft 222 has a composite form and includes a first segment 244 and a second segment 246. The first segment 244 and the second segment 246 are made of different materials. For example, the first segment 244 is a solid metal construction, while the second segment 246 is a composite material construction. In a specific example, the first segment 244 is steel, and the second segment 246 is a carbon fiber composite material.

[0065] Although the first segment 244 and the second segment 246 can be connected end-to-end, in the example shown, the second segment 246 is located radially outside the first segment 244.

[0066] A first segment 244 of the drive shaft 222 provides a first end 240 of the drive shaft 222. The first segment 244 of the drive shaft 244 has a second end 248 that connects to the first end 250 of the second segment 246. The second end 252 of the second segment 246 is connected to the connecting hub 234.

[0067] The first segment 244 of the drive shaft 222 is elongated and extends through the center of the opening of the connecting hub 234. A connecting flange 254 at the second end 252 of the first segment 244 provides a connection interface with the first end 250 of the second segment 246. This is because the outer diameter of the connecting flange 254 is smaller than the inner diameter of the first end 250 of the second segment 246 of the drive shaft 222.

[0068] The interface between the first section 244 and the second section 246 at the connecting flange 254 can be achieved by any suitable means, but is shown here as a bolted connection provided by the circumferential ring of the bolt 256.

[0069] Due to the arrangement of the radially outer second section 246 of the drive shaft 222 relative to the radially inner first section 244, the drive shaft 222 can be considered to have a complex load path, as torque is transmitted along the first section 244 and then along the radially outer second section 246. Usefully, in the case that the radially outer second section 246 is formed of a composite material, the additional flexibility in this section can provide a useful reduction in noise generation.

[0070] The construction of drive shaft 222 also provides an opportunity to achieve a second connection between drive shaft 222 and rotor connecting hub 234. Figure 8 This is illustrated by the torque bypass device 260.

[0071] As in the previously discussed examples of the invention, the torque bypass device 260 of this example acts as a fail-safe device when the drive shaft 222 experiences a mechanical failure between the first end 240 and the second end 242. For example, in Figure 8In the construction, the second section 246 of the drive shaft 222 (as a composite component) may experience a mechanical failure, which means that it cannot effectively transmit torque to the connecting hub 234 of the rotor.

[0072] The torque bypass device 260 in the example shown also includes a torque transmission member 264 and a torque receiving member 266. The torque transmission member 264 is composed of a disc-shaped component, while the torque receiving member 266 is composed of a rotor connecting hub 234.

[0073] The cross section passing through torque transmission member 264 along line AA is visible in Figure 9 .

[0074] Also refer to Figure 9 It is understood that the torque transmission component 264 is a separate component from the drive shaft 222 and is fixed to the drive shaft 222 by a set of bolts 267, which connect the torque transmission component 264 to the integral flange 269 formed on the drive shaft. Other arrangements are also acceptable.

[0075] In the figure, it can be seen that the bolts 267 are arranged in a circular array, which securely connects the torque transmission component 264 to the annular flange 269.

[0076] As already mentioned, the torque transmission member 264 is in the form of a disc. The torque transmission member 264 and the torque receiving member 266 are configured in a complementary manner so that they do not come into contact with each other during normal operation of the gearbox 212 and the generator 214.

[0077] For this purpose, the torque transmission member 264 is shaped to define one or more protrusions 270. In the example shown, there are four protrusions 270, arranged at equal angles at 90-degree intervals around the disk. This produces a balanced torque transmission.

[0078] In a manner complementary to the torque transmission member 264, the torque receiving member 266 is shaped to define four sockets 272, each corresponding to one of the four protrusions 270.

[0079] Although in this example the torque transmission member 264 provides a protrusion 270 and the torque receiving member 277 provides a socket 272, it should be understood that this configuration can be reversed.

[0080] It will be noted that the geometry of the corresponding protrusion 270 and socket 272 defines a gap or void C between them. As in the previous example, this means that during normal operation of the gearbox 212 and generator 214, the protrusion 270 and socket 272 do not come into contact with each other.

[0081] The gap C allows for relative movement in the circumferential direction between the torque transmission member 264 and the torque receiving member 266, which can take the form of high-frequency vibration and low-frequency torque reversal. The gap C accommodates this relative angular movement and ensures that no torque transmission occurs during normal operation.

[0082] However, in the event of a mechanical failure in drive shaft 222 (e.g., at the second segment 246), it will be understood that the first segment 244 will twist relative to the second segment 246. This will cause torque transmission member 264 to rotate relative to torque receiving member 266.

[0083] The outer surface of the corresponding protrusion 270 will therefore be forced to contact the inner surface of the corresponding socket 272.

[0084] Shock absorption can be provided in several ways. One option is to incorporate a relatively soft bushing (not shown) into the gap space C between the protrusion 27 and the socket 272. This will provide some energy dissipation for impact loads between the torque transmission member 264 and the torque receiving member 266. Furthermore, it will be noted that... Figure 9 In the middle, the protrusion 270 and the socket 272 define mutually inclined surfaces that come into contact when the torque transmission member 264 is activated, and those inclined surfaces provide a wedging effect, as discussed above.

[0085] Another option is Figure 9 As shown in the diagram, each protrusion 270 is provided with a hole 276. In this example, the hole 276 is circular, although this is not necessary. The hole 276 provides a weakened area for the corresponding protrusion 270, allowing some deformation when the protrusion 270 impacts the socket 272. The deformation of the protrusion 270 at the point of impact provides some energy dissipation and thus provides the impact buffering function discussed above, thereby enhancing the wedging effect discussed above.

[0086] Those skilled in the art will understand that modifications can be made to the illustrated examples without departing from the inventive concept defined by the claims.

[0087] For example, one will notice in Figure 9 In the example shown, there are four protrusions 270 arranged at equal angles of 90 degrees around the disc, and four corresponding sockets 272. However, fewer or more pairs of protrusions and sockets are possible compared to the example shown. Furthermore, in a contemplated variation, when viewed in cross-section, the torque transmitting member 264 may be generally elliptical or oval in its outer profile, while the torque receiving member 266 may have a generally elliptical inner cross-sectional profile. This configuration in… Figure 10 The figures are shown in a simplified form. The complementary contours of the torque transmission member 264 and the torque receiving member 266 will be shown in accordance with... Figure 9The example shown operates in a similar manner. Therefore, it will be understood that in this example, two pairs of protrusions 270 and sockets 272 are provided, which have an enlarged form compared to the previously shown example.

[0088] Further examples are in Figure 11 The diagram is shown in a simplified form. In this example, the torque transmission member 264 includes a protrusion 270 in the form of a rod 274. The rod 274 extends radially outward and has an outer end received within a corresponding socket 272 defined in the torque receiving member 266. The geometry of the socket 272 is configured such that it is larger than the end of the rod 274, resulting in functionality equivalent to the previously described example. It should be noted that this configuration can be reversed, such that the rod 274 can extend radially inward and be received into the socket defined by the torque transmission member 264.

Claims

1. A transmission device for a wind turbine, the transmission device comprising: A gearbox (12) with a drive output side, A generator (14) with a drive input side, A drive shaft (22, 222) extends between the drive output side and the drive input side and defines a rotation axis (X). In operation, torque is transmitted from the drive output side to the drive input side via the drive shaft (22). The transmission device also includes a torque bypass device (40, 140, 260) associated with the drive shaft. The torque bypass device is configured such that, in the event of a mechanical failure of the drive shaft during use, torque is transmitted from the drive output side of the gearbox to the drive input side of the generator by the torque bypass device.

2. The transmission device according to claim 1, wherein, The torque bypass device (40, 140, 260) includes a torque transmission member (42, 142, 264) and a torque receiving member (44, 144, 266), wherein the torque transmission member and the torque receiving member are configured such that torque is transmitted to the torque receiving member only when a mechanical failure occurs in the drive shaft.

3. The transmission device according to claim 2, wherein, The torque transmission member (42, 142, 264) can engage with the torque receiving member (44, 144, 266) such that a gap (C) is defined between the torque transmission member and the torque receiving member during normal operation of the transmission device.

4. The transmission device according to claim 3, wherein, An impact buffer (62) is provided between the torque transmission component and the torque receiving component.

5. The transmission device according to claim 4, wherein, The impact buffer (62) is provided by or within the gap (C) between the torque transmission member and the torque receiving member.

6. The transmission device according to claim 5, wherein, The impact buffer (62) is provided by an elastic member (60) received in the gap (C) between the torque transmitting member and the torque receiving member.

7. The transmission device according to claim 5 or 6, wherein, The impact buffer (62) is also provided by the mutually inclined surfaces of the torque transmission member (42, 142, 264) and the torque receiving member (44, 144, 266), such that when the torque transmission member rotates relative to the torque receiving member more than a predetermined angle threshold, the mutually inclined surfaces wedge together to transmit torque.

8. The transmission device according to any one of claims 5 to 7, wherein, The impact buffer (62) is also provided by selecting at least a portion of the material of the torque transmission member and the torque receiving member, such that controlled yielding is achieved in use when the torque transmission member transmits torque to the torque receiving member.

9. The transmission device according to any one of the preceding claims, wherein, The torque transmission member (42, 142, 264) is connected to the drive shaft (22, 222) at a first axial position, and the torque receiving member is connected to the drive shaft at a second axial position spaced apart from the first axial position along the axis of rotation.

10. The transmission device according to any one of the preceding claims, wherein, The drive shaft (22, 222) is at least partially formed of composite material.

11. The transmission device according to claim 10 when referring to claim 9, wherein, The drive shaft (22, 222) includes a composite material section extending at least between the first axial position and the second axial position.

12. The transmission device according to claim 10, wherein, The drive shaft (22, 222) has a first section (244) and a second section (246), wherein the second section (246) is formed of the composite material.

13. The transmission device according to claim 12, wherein, The first section (244) of the drive shaft (22, 222) is formed of a metallic material.

14. The transmission device according to claim 12 or 13, wherein, The torque transmission component (264) is connected to the first section (244) of the drive shaft (222).

15. The transmission device according to any one of claims 12 to 14, wherein, The torque receiving component (266) is connected to the second section (246) of the drive shaft (222).

16. The transmission device according to any one of claims 12 to 15, wherein, The second section (246) of the drive shaft (222) is located radially outside the first section (244) of the drive shaft (222) relative to the axis of rotation (X).

17. The transmission device according to any one of claims 10 to 16, wherein, The torque receiving component (266) includes the drive input side (234) of the generator (14, 214).

18. A wind turbine comprising a transmission device according to any one of the preceding claims.

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