Device for aligning holes

Abstract

To provide a device 100 configured for aligning a first hole 131 of a first flange 130 with a second hole 141 of a second flange 140.SOLUTION: The device 100 comprises a base 101, a shaft 110 extending from the base 101, and a first and a second pusher 115, 116. The shaft 110 is able to move between a retracted position and an extended position. The shaft 110 in the extended position extends from the first hole 131 into the second hole 141. The first and second pushers 115, 116 are also configured to be moved radially outwardly from the shaft 110 to exert pressure against an inner wall of the first and second holes 131, 141. Methods for aligning a first and a second hole 130, 140 are also provided.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to devices for aligning holes. More particularly, the present disclosure relates to devices configured to align two holes in respective flanges. The present disclosure further relates to methods and systems for aligning two flanges and joining one flange to another flange, in particular for joining a flange of a tower section to a flange of another tower section. The present disclosure further relates to joining flanges of tower sections of a wind turbine tower. [Background technology]

[0002] Modern wind turbines are commonly used to provide electricity to the electrical grid. This type of wind turbine typically includes a tower and a rotor disposed on the tower. The rotor usually consists of a hub and a number of blades, which rotate under the influence of the wind on the blades. This rotation generates a torque that is typically transferred via the rotor shaft to a generator, either directly ("direct drive" or "gearless") or using a gearbox. The generator then generates electrical power that can be provided to the electrical grid.

[0003] Wind turbines have evolved rapidly over the last few decades, with a clear trend towards larger sizes. The power generated by a wind turbine is proportional to the rotor swept area, and therefore to the square of the blade length. Therefore, taller towers and longer blades have been used to extract more energy from the wind and obtain higher power output. Over the years, the increase in size has led to a significant increase in the loads acting on wind turbine components, posing new challenges to a wide range of disciplines, including mechanical, electrical, material and civil engineering.

[0004] Modern high rise wind turbines have large tubular towers configured to withstand increasing loads. As such, tubular towers may be manufactured with thick walled and large diameter substantially tubular sections. In some cases, the tubular sections may be made from multiple segments attached to each other. Such large parts also result in a more complicated and expensive assembly process. Although the tower sections may be generally described herein as tubular, it will be apparent that the tower sections may be substantially cylindrical (constant diameter or constant cross-sectional dimension) or conical, with the diameter or cross-sectional dimension at the lower end of the tower section being larger than the diameter or cross-sectional dimension at the upper end of the section.

[0005] Typically, the tower sections are made of concrete or steel. The sections may include flanges at the bottom (to join to a lower tower section or foundation) and flanges at the top (to join to a higher tower section or yaw bearing). These flanges may be combined with fasteners such as studs, bolts, rods, etc. to provide a secure connection between adjacent tower sections. To further facilitate the installation of the towers, it is important to maintain the substantially circular cross-section of the tubular sections, so that they conform to the shape of the mating tubular sections to which they are connected. Thus, holes in the fasteners that join one flange to another can be better aligned with holes in the other flange. Proper alignment can reduce stresses in the fasteners.

[0006] Despite manufacturing efforts to produce tubular sections with circular cross sections, prolonged storage can lead to the self-weight of the tower sections exerting large and sustained forces on the sections. In fact, the force of the section's own weight has been found to cause ovalization of circular sections, including the flanges.

[0007] Deformation of tower sections can lead to misalignment, which can lead to increased tension on fasteners as well as disrupt the tower installation process, making it longer and more expensive.

[0008] Typically, heavy mobile cranes are used to erect wind turbines with prefabricated tubular sections. As such mobile cranes are relatively expensive, it is of interest to reduce the time that these cranes are used for a given wind turbine. Furthermore, for health and safety reasons, known methods for erecting wind turbines generally require personnel to be present inside the tower as subsequent sections are installed. Therefore, an apparatus and associated methods that facilitate remote installation of tubular sections of a wind turbine would also be welcome in the art.

[0009] The present disclosure provides methods and systems that at least partially overcome some of the aforementioned shortcomings. Summary of the Invention

[0010] In one aspect of the disclosure, an apparatus for aligning a first hole of a first flange with a second hole of a second flange is provided. The apparatus includes a base, a shaft extending from the base, and first and second pushers. The shaft is configured to move between a retracted position and an extended position. In the extended position, the shaft extends from the first hole to the second hole. Further, when the shaft is in the extended position, the first and second pushers are configured to be located within the first and second holes, respectively. Also, the first and second pushers are configured to move radially outward from the shaft to exert pressure against inner walls of the first and second holes, respectively.

[0011] According to this aspect, the fact that the device includes the first and second pushers configured to be placed in the first and second holes can provide accurate alignment of the first and second holes of the flange. In fact, the first and second pushers also align the device with respect to the first and second holes, so that no pre-alignment between the device and the first hole is required. Thus, the connection of the flanges, such as when erecting a wind turbine tower structure, is greatly simplified. This saves time during installation and allows for a convenient remote alignment operation.

[0012] In a further aspect, a method of aligning a first hole of a first flange with a second hole of a second flange is disclosed. The method includes attaching a base of a device to the first flange such that a shaft of the device extends into the first hole of the first flange. The shaft of the device includes a first pusher and a second pusher. Further, the method includes extending the shaft through the first hole and into the second hole such that the first pusher is disposed inside the first hole and the second pusher is disposed inside the second hole. The method also includes moving the first and second pushers radially outward from the shaft such that the first and second pushers exert pressure against inner walls of the first and second holes, respectively.

[0013] According to this additional aspect, the alignment between the two flanges can be improved. The shaft can be moved into the first and second holes even if the holes are not perfectly aligned, i.e., the overlap between the holes must be greater than the thickness of the shaft. Furthermore, the alignment can be enhanced by the first and second pushers. The alignment between the holes from the first flange and the corresponding holes from the second flange can also be improved, thus simplifying the joining process and reducing the overall installation time.

[0014] Thus, when the apparatus and methods are used to install wind turbine components, the use of cranes and other lifting equipment may be more efficient than conventional methods, making the assembly process faster and cheaper.

[0015] Throughout this disclosure, the term "align" should be understood as placing two or more components into a line. For example, two or more holes may be aligned by aligning the center points or axes of the holes into a line. In some instances, the holes may be similar in shape or size, and aligning in this manner causes the holes to substantially coincide with one another.

[0016] In the present disclosure, a pusher may be considered to be any element suitable for actively or passively exerting pressure towards the inner surface of the bore. The pusher may be configured as one or more clamps, wedges, or other suitable elements.

[0017] Throughout this disclosure, the term coefficient of friction should be understood as the ratio of the frictional force resisting the movement of two surfaces in contact to the normal force pressing the two surfaces together. Unless otherwise specified, the coefficient of friction used refers to the static coefficient of friction, i.e., the coefficient of friction before the relative motion between the two surfaces begins. When referring to "low friction material" and "high friction material," these terms should be understood to refer to materials that generally have a low, i.e., less than 0.5, or high, i.e., greater than 0.5, coefficient of friction with a wide range of materials.

[0018] Additional objects, advantages and features of the embodiments of the present disclosure will become apparent to those skilled in the art upon examination of the specification or may be learned by practice. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a schematic perspective view of an example wind turbine. [Diagram 2] 1 shows an example of a wind turbine hub and nacelle. [Diagram 3] 1 shows a schematic cross-section of a wind turbine tower with a flange equipped with a device according to the present disclosure. [Figure 4] 1A and 1B show schematic cross-sectional views of two flanges of an exemplary device according to the present disclosure in a first position. [Diagram 5] 1A and 1B show schematic cross-sectional views of two flanges of an exemplary device according to the present disclosure in a second position. [Figure 6] 13A-13C are schematic cross-sectional views of two flanges of an exemplary device according to the present disclosure in a third position; [Figure 7] 5 is a flow chart illustrating an example of a method for aligning a first hole in a first flange with a second hole in a second flange. [Figure 8] 1 is a flow chart illustrating an example method for erecting a wind turbine tower including multiple tower sections. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Reference will now be made in detail to the embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of illustration and not by way of limitation. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the teachings. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield still further embodiments. Thus, it is intended that the present disclosure cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0021] FIG. 1 is a perspective view of an example of a wind turbine 10. In this example, the wind turbine 10 is a horizontal axis wind turbine. Alternatively, the wind turbine 10 may be a vertical axis wind turbine. In this example, the wind turbine 10 includes a tower 15 extending from a support system 14 on a ground 12, a nacelle 16 attached to the tower 15, and a rotor 18 coupled to the nacelle 16. The rotor 18 includes a rotatable hub 20 and at least one rotor blade 22 coupled to the hub 20 and extending outwardly from the hub 20. In this example, the rotor 18 has three rotor blades 22. In alternative embodiments, the rotor 18 includes more or less than three rotor blades 22. The tower 15 may be fabricated from tubular steel to define a cavity (not shown in FIG. 1) between the support system 14 and the nacelle 16. In alternative embodiments, the tower 15 may be any suitable type of tower having any suitable height. According to an alternative, the tower may be a hybrid tower comprising a concrete portion and a steel tubular portion. It may also be a partial or complete lattice tower.

[0022] The rotor blades 22 are spaced relative to the hub 20 to rotate the rotor 18 and convert kinetic energy from the wind into usable mechanical energy, and therefore electrical energy. The rotor blades 22 are mated to the hub 20 by coupling blade root portions 24 to the hub 20 at a number of load transfer regions 26. The load transfer regions 26 may include hub load transfer regions and blade load transfer regions (both not shown in FIG. 1 ). Loads induced in the rotor blades 22 are transferred to the hub 20 via the load transfer regions 26.

[0023] In examples, the rotor blades 22 may have a length ranging from about 15 meters (m) to about 90 m or more. The rotor blades 22 may have any suitable length that enables the wind turbine 10 to function as described herein. For example, non-limiting examples of blade lengths include lengths of 20 m or less, 37 m, 48.7 m, 50.2 m, 52.2 m, or more than 91 m. When wind strikes the rotor blades 22 from a wind direction 28, the rotor 18 rotates about a rotor axis 30. As the rotor blades 22 rotate and experience centrifugal forces, the rotor blades 22 also experience various forces and moments. As such, the rotor blades 22 may deflect and / or rotate from a neutral, i.e., unbiased, position to a biased position.

[0024] Additionally, the pitch angle of the rotor blades 22, i.e., the angle determining the orientation of the rotor blades 22 relative to the wind direction, can be varied by a pitch system 32 to control the load and power generated by the wind turbine 10 by adjusting the angular position of at least one rotor blade 22 relative to the wind vector. A pitch axis 34 of the rotor blades 22 is shown. During operation of the wind turbine 10, the pitch system 32 can, among other things, vary the pitch angle of the rotor blades 22 to reduce the angle of attack of (some of) the rotor blades, thereby facilitating a reduction in rotational speed and / or facilitating a stall of the rotor 18.

[0025] In this embodiment, the blade pitch of each rotor blade 22 is individually controlled by the wind turbine controller 36 or pitch control system 80. Alternatively, the blade pitch of all rotor blades 22 may be simultaneously controlled by these control systems.

[0026] Furthermore, in this embodiment, as the wind direction 28 changes, the yaw direction of the nacelle 16 can be rotated about a yaw axis 38 to position the rotor blades 22 relative to the wind direction 28 .

[0027] Although in this example, wind turbine controller 36 is shown as centralized in nacelle 16, wind turbine controller 36 may be a distributed system throughout wind turbine 10, on support system 14, within a wind farm, and / or at a remote control center. Wind turbine controller 36 includes a processor 40 configured to perform the methods and / or steps described herein. Additionally, many of the other components described herein include a processor.

[0028] As used herein, the term "processor" is not limited to integrated circuits referred to in the art as computers, but refers broadly to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific, integrated circuits, and other programmable circuitry, and these terms are used interchangeably herein. It should be understood that a processor and / or control system may also include memory, input channels, and / or output channels.

[0029] 2 is an enlarged cross-sectional view of a portion of the wind turbine 10. In this example, the wind turbine 10 includes a nacelle 16 and a rotor 18 rotatably coupled to the nacelle 16. More specifically, a hub 20 of the rotor 18 is rotatably coupled to a generator 42 disposed within the nacelle 16 by a main shaft 44, a gearbox 46, a high-speed shaft 48, and a coupling 50. In the example, the main shaft 44 is disposed at least partially coaxially with a longitudinal axis (not shown) of the nacelle 16. Rotation of the main shaft 44 drives a gearbox 46, which drives the high-speed shaft 48 by converting the relatively slow rotational motion of the rotor 18 and main shaft 44 into a relatively fast rotational motion of the high-speed shaft 48. The latter is connected, with the aid of the coupling 50, to the generator 42 for producing electrical energy. Further, a transformer 90 and / or appropriate electronics, switches, and / or inverters may be disposed within the nacelle 16 to convert the electrical energy generated by the generator 42 having a voltage of 400V-1000V into electrical energy having a medium voltage (10-35KV). The electrical energy is conducted from the nacelle 16 to the tower 15 via a power cable.

[0030] The gearbox 46, the generator 42 and the transformer 90 may be supported by a main support structural frame of the nacelle 16, optionally embodied as a main frame 52. The gearbox 46 may include a gearbox housing coupled to the main frame 52 by one or more torque arms 103. In an embodiment, the nacelle 16 also includes a main forward support bearing 60 and a main aft support bearing 62. Furthermore, the generator 42 may be mounted to the main frame 52 by a decoupling support means 54, particularly to prevent vibrations of the generator 42 from being introduced into the main frame 52 and thereby causing a source of noise emissions.

[0031] Optionally, the main frame 52 is configured to carry the weight of the rotor 18 and nacelle 16 components, as well as the overall loads caused by wind and rotational loads, and to introduce these loads into the tower 15 of the wind turbine 10. The rotor shaft 44, generator 42, gearbox 46, high speed shaft 48, coupling 50, and supports 52, and any associated fastening, supporting, and / or fastening devices, including, but not limited to, a forward support bearing 60 and an aft support bearing 62, may be referred to as a drive train 64.

[0032] In some embodiments, the wind turbine may be a direct drive wind turbine without a gearbox 46. The generator 42 operates at the same rotational speed as the rotor 18 of the direct drive wind turbine and therefore typically has a much larger diameter than the generator used in a wind turbine with a gearbox 46 to provide the same amount of power as a wind turbine with a gearbox 46.

[0033] The nacelle 16 may also include a yaw drive mechanism 56 that is used to rotate the nacelle 16, and thereby the rotor 18, about the yaw axis 38 to control the approach or approach of the rotor blades 22 relative to the wind direction 28.

[0034] To properly position the nacelle 16 with respect to the wind direction 28, the nacelle 16 may also include at least one meteorological measurement system 58 including a wind vane and an anemometer. The meteorological measurement system 58 may provide information including the wind direction 28 and / or wind speed to the wind turbine controller 36. In this embodiment, the pitch system 32 is at least partially disposed within the hub 20 as a pitch assembly 66. The pitch assembly 66 includes one or more pitch drive systems 68 and at least one sensor 70. Each pitch drive system 68 is coupled to a respective rotor blade 22 (shown in FIG. 1 ) for modulating the pitch angle of the rotor blade 22 along the pitch axis 34. Only one of the three pitch drive systems 68 is shown in FIG. 2 .

[0035] In this embodiment, the pitch assembly 66 includes at least one pitch bearing 72 coupled to the hub 20 and each rotor blade 22 (shown in FIG. 1 ) to rotate each rotor blade 22 about the pitch axis 34. The pitch drive system 68 includes a pitch drive motor 74, a pitch drive gearbox 76, and a pitch drive pinion 78. The pitch drive motor 74 is coupled to the pitch drive gearbox 76 such that the pitch drive motor 74 provides a mechanical force to the pitch drive gearbox 76. The pitch drive gearbox 76 is coupled to the pitch drive pinion 78 such that the pitch drive pinion 78 is rotated by the pitch drive gearbox 76. The pitch bearing 72 is coupled to the pitch drive pinion 78 such that rotation of the pitch drive pinion 78 causes rotation of the pitch bearing 72.

[0036] The pitch drive system 68 is coupled to the wind turbine controller 36 for adjusting the pitch angle of the rotor blades 22 in response to one or more signals from the wind turbine controller 36. In this example, the pitch drive motor 74 is any suitable motor driven by an electric power and / or hydraulic system that enables the pitch assembly 66 to function as described herein. Alternatively, the pitch assembly 66 may include any suitable structure, configuration, arrangement, and / or components, such as, but not limited to, hydraulic cylinders, springs, and / or servo mechanisms. In certain embodiments, the pitch drive motor 74 is driven by the rotational inertia of the hub 20 and / or energy extracted from a stored energy source (not shown) that provides energy to components of the wind turbine 10.

[0037] The pitch assembly 66 may also include one or more pitch control systems 80 for controlling the pitch drive systems 68 in accordance with control signals from the wind turbine controller 36 in case of certain preferred conditions and / or upon overspeed of the rotor 18. In an example embodiment, the pitch assembly 66 includes at least one pitch control system 80 communicatively coupled to each pitch drive system 68 for controlling the pitch drive systems 68 independently from the wind turbine controller 36. In an example embodiment, the pitch control system 80 is coupled to the pitch drive systems 68 and to the sensor 70. During normal operation of the wind turbine 10, the wind turbine controller 36 may control the pitch drive systems 68 to adjust the pitch angle of the rotor blades 22.

[0038] According to one embodiment, a generator 84, including, for example, a battery and an electrical capacitor, is disposed at or within the hub 20 and is coupled to the sensors 70, the pitch control system 80, and the pitch drive system 68 to provide a source of electrical power to these components. In this example, the generator 84 provides a continuous source of electrical power to the pitch assembly 66 during operation of the wind turbine 10. In an alternative embodiment, the generator 84 provides electrical power to the pitch assembly 66 only during a power loss event of the wind turbine 10. A power loss event may include a loss or dip in the electrical grid, a malfunction of the electrical system of the wind turbine 10, and / or a failure of the wind turbine controller 36. During a power loss event, the generator 84 operates to provide electrical power to the pitch assembly 66 such that the pitch assembly 66 can operate during the power loss event.

[0039] In this example, pitch drive system 68, sensor 70, pitch control system 80, cables, and generator 84 are each disposed within a cavity 86 defined by an inner surface 88 of hub 20. In alternative embodiments, these components may be positioned relative to and directly or indirectly coupled to an outer roof surface of hub 20.

[0040] FIG. 3 is a schematic cross-sectional view of a wind turbine tower 15 under construction. In particular, FIG. 3 shows two cone-shaped tower sections 151, 152 including mounting flanges 130, 140. In this example, the upper tower section 151 includes a lower mounting flange 130 that is substantially aligned with an upper mounting flange 140 of the lower tower section 152. Although two devices 100 configured to align holes in the mounting flanges are illustrated in the schematic cross-section, other numbers of devices 100 may be used for this purpose. The devices 100 may also be used for other types of tower sections, such as tower sections having a circular cross-section with a substantially constant diameter. It is noted that the cut surfaces in FIG. 3 are not shown with cross-hatched lines for simplicity reasons.

[0041] 4 to 6 show in more detail the working principle of the device 100 shown in FIG.

[0042] 4 shows a schematic cross-sectional view of two flanges with an apparatus 100 according to an embodiment of the present disclosure in a first position. The apparatus 100 is configured to align a first hole 131 of the first flange 130 with a second hole 141 of the second flange 140. The apparatus 100 comprises a base 101, a shaft 110 extending from the base 101, and first and second pushers 115, 116. The shaft 110 is configured to move between a retracted position and an extended position. When the shaft 110 is in the extended position, the shaft 110 extends from the first hole 131 to the second hole 141. Furthermore, when the shaft 110 is in the extended position, the first and second pushers 115, 116 are configured to be located within the first and second holes 131, 141, respectively. The first and second pushers 115, 116 are also configured to move radially outward from the shaft 110 to exert pressure against the inner walls of the first and second holes 131, 141, respectively. This aspect is described in further detail in relation to Figures 5 and 6.

[0043] The base 101 may be attached to the first flange 130. Thus, in some embodiments, the base 101 may include a fastening element for connecting the base 101 to the first flange 130. The fastening element may be a screw element, a clamp element, or others.

[0044] As can be seen by way of example in Fig. 4, the pushers 115, 116 can be located at least partially inside the shaft 110 when they are not activated, i.e. before and during the insertion of the shaft 110 into the first and second holes 131, 141. The diameter of the shaft 110 is thus reduced, allowing an insertion with a relatively large offset between the holes 131, 141. In Fig. 4, the device is in the extended position, i.e. the shaft 110 is at least partially introduced into the first and second holes 131, 141.

[0045] It should be noted that the base 101 in this embodiment is shown diagrammatically in FIG. 4. The base 101 may be of different shapes and sizes, i.e., may be sized to accommodate other device components therein. For example, the base 101 may include a rim for mounting the device to the first flange 130. In an embodiment, the rim may have a cross-section substantially larger than the cross-section of the shaft to enhance stability of the device 100 on the flange 130. In some embodiments, the base 101 may include an actuator assembly for actuating the shaft 110 and / or the first and second pushers 115, 116.

[0046] In some embodiments, the actuator assembly may be comprised of one or more of a pneumatic actuator, a hydraulic actuator, an electric actuator, a stepper motor, a rotary actuator, or a combination of actuators. For example, the actuator assembly may be comprised of a pneumatic or hydraulic actuator for moving the shaft 110 between a retracted position and an extended position. Additionally, the actuator assembly may be comprised of another actuator for displacing the body longitudinally along the shaft and moving the first and second pushers 115, 116 against the inner walls of the respective bores 131, 141.

[0047] In some embodiments, the apparatus 100 may include a receiver or receiver unit and a controller. The receiver unit may be configured to receive a signal of a remote control. The receiver unit may be configured to receive a signal from a remote control device. The device may be other devices, for example, for aligning the third hole and the fourth hole of the flange. Furthermore, the device may be other types of devices, such as an interphase device for transmitting information to a master controller or an operator. Furthermore, the controller may be configured to operate the actuator assembly according to the received signal.

[0048] 5 is a schematic cross-sectional view of the two flanges of the device according to the embodiment of FIG. 4 in a second position. In FIG. 5, the first and second pushers 115, 116 are moved radially outward from the shaft 110. The pushers 115, 116 contact the inner walls of the holes 131, 141 and exert pressure against the inner walls of the first and second holes 131, 141, respectively. Thus, when the pushers 115, 116 are actuated, the radial clearance between the shaft 110 and the inner walls of the holes 131, 141 is modified, and the holes 131, 141 are aligned. In some examples, when the shaft 110 and the holes 131, 141 are cylindrical, the pushers 115, 116 can form a substantially uniform radial clearance between the inner walls of the holes 131, 141 and the outer surface of the shaft 110.

[0049] 5 further illustrates that the pushers 115, 116 may be a plurality of wedges. The pushers may in particular be a pair of diametrically opposed elements such as wedges. In other examples, the pushers may include a pair of substantially semicircular parts or other elements. The pushers 115, 116, i.e. the wedges, may be connected to an actuator assembly as previously disclosed. Thus, when the pushers 115, 116 are moved radially, they are able to overcome the resistance resulting from the weight of the flanges 130, 140 and the friction of the flanges with adjacent elements. In an embodiment, the pushers 115, 116 and the associated actuators may be configured to cause a local deformation of the flanges 130, 140 that they act on. Thus, the pushers 115, 116 are able to successfully align the first and second holes 131, 141 as previously disclosed.

[0050] As can be seen in FIG. 5, once the pushers 115, 116 are deployed, the first and second holes 131, 141 in the respective flanges 130, 140 are aligned.

[0051] The pushers 115, 116 may be made of a material with high mechanical properties, i.e., a material that has sufficient strength to overcome the lateral resistance of the flanges, i.e., to move the flanges laterally or to overcome a certain level of possible ovalization of the flanges, optionally without undergoing plastic deformation. In an embodiment, the pushers 115, 116 may be made of a metal or metal alloy, for example stainless steel.

[0052] FIG. 6 is a schematic cross-sectional view of the two flanges of an exemplary device according to the present disclosure in a third position. As shown in FIG. 6, the two flanges 130, 140 are in contact. This can be achieved by at least partially moving the shaft 110 from an extended position to a retracted position. In the illustrated example, the shaft 110 is moved to the retracted position, i.e., a position retracted into the base 101. Furthermore, the first pusher 115 may be configured to slide along the inner wall of the first hole 131 when the shaft 100 is moved from the extended position toward the retracted position. Furthermore, the second pusher 116 may be configured to be substantially fixed relative to the inner wall of the second hole 141. Thus, relative movement between the first flange 130 (slidably coupled to the first pusher 116 and the shaft 110) and the second flange 140 (rigidly coupled to the second pusher 116 and the shaft 110) is facilitated. In this manner, the flanges can be fixed to each other.

[0053] In some embodiments, the first flange 130 may be the mounting flange of the upper tower section 151 and the second flange 140 may be the mounting flange of the lower tower section 152. As shown in FIG. 3, the upper tower section 151 may be held by a crane (not shown) or any other type of lifting equipment during the erection of the tower. The shaft 110 of one or more devices 100 then extends from a first hole in one of the mounting flanges 130, 140 to another hole in the other of the mounting flanges 130, 140, and the crane can be removed once the mounting flanges 130, 140 are substantially aligned (and optionally secured, as shown in FIG. 6). In this way, the securing of the flanges 130, 140 can finally be performed without the use of a crane. The same reasoning applies to any other lifting equipment that may be used during the construction of the tower.

[0054] In another embodiment, the first pusher 115 may be configured to slide along the shaft 110 as the shaft 100 is moved from the extended position toward the retracted position. Additionally, the second pusher 116 may be configured to be substantially fixed against an inner wall of the second bore 141, thus facilitating relative movement between the first flange 130 (slidably coupled to the shaft 110) and the second flange 140 (rigidly coupled to the shaft 110).

[0055] To facilitate relative motion between the first flange 130 and the second flange 140, the coefficient of friction between the surface of the inner wall of the first hole 131 and the outer surface of the first pusher 115 may be lower than the coefficient of friction between the surface of the inner wall of the second hole 141 and the outer surface of the second pusher 116. In some embodiments, the coefficient of friction between the surface of the inner wall of the first hole 131 and the outer surface of the first pusher 115 may be 0.5 or less, specifically 0.35 or less, more specifically 0.2 or less. This may be achieved by selecting a suitable set of materials for the inner wall of the first hole 131 and the first pusher 115, using a suitable material or using a dedicated skin or coating covering the contacting surfaces, or including a lubricant. For example, the first pusher 115 may be made of stainless steel with a polyethylene or polytetrafluoroethylene (PTFE) skin, and the inner wall of the first hole 131 may be made of stainless steel. This combination of materials results in a coefficient of friction of approximately 0.2 to 0.1. Additionally, low friction materials, i.e., materials that have a low coefficient of friction with a wide range of materials, may be used for at least one of the first pusher 115 and the first bore 131. Additionally, the inner wall of the first bore 131 and the outer circumferential surface of the first pusher 115 may be treated to achieve a relatively smooth surface finish. Additionally, combinations of these and other materials may be used in combination with liquid or solid lubrication, such as vegetable oils, mineral oils, synthetic liquid lubricants, graphite, molybdenum disulfide or boron nitride among others.

[0056] In some embodiments, to promote a strong contact point between the second pusher 116 and the inner wall of the second hole 141, the coefficient of friction between these elements may be 0.7 or more, specifically 0.8 or more, more specifically 1 or more. As mentioned above, this can be achieved by selecting an appropriate set of materials, for example using steel or aluminum alloy for both elements. Furthermore, high friction materials, i.e. materials with a high coefficient of friction with a wide range of materials, may be used for the second pusher 116 and / or the second hole 141. Furthermore, the overall friction that may be experienced between the inner wall of the second hole 141 and the second pusher 116 may also be enhanced by a pusher with an irregular surface finish, i.e. rough walls, serrated surface, or other.

[0057] In another aspect of the present disclosure, a method 400 is disclosed. The method 400 is suitable for aligning a first hole 131 of a first flange 130 with a second hole 141 of a second flange 140. The method 400 is shown generally in FIG.

[0058] The method 400 includes, in block 401, attaching the base 101 of the device 100 to a first flange 130 such that the shaft 110 of the device 100 extends into a first hole 131 of the first flange 130, the shaft 110 having a first pusher 115 and a second pusher 116.

[0059] The method 400 also includes, in block 402, extending the shaft 110 through the first hole 131 and into the second hole 141 such that the first pusher 115 is positioned inside the first hole 131 and the second pusher 116 is positioned inside the second hole 141.

[0060] The method 400 includes, at block 403, moving the first and second pushers 115, 116 radially outward from the shaft 110 against the inside of the first hole 131 and the second hole 141, respectively. This step allows the first hole 131 and the second hole 141 to align.

[0061] In some embodiments, the method 400 may include retracting the shaft 110 of the device 100 such that the relative motion between the first flange 130 and the shaft 110 is greater than the relative motion between the second flange 140 and the shaft 110. This may be accomplished by relative sliding of the first pusher 115 against the shaft 110 or the inner wall of the first bore 131, as discussed in connection with FIG.

[0062] Further, in an embodiment, the method 400 may include fastening the first flange 130 and the second flange 140 together.

[0063] In this embodiment, the first flange 130 in method 400 may be a lower mounting flange of a first tower section 151 of the wind turbine tower 15, and the second flange 140 may be an upper mounting flange of a second tower section 152 of the wind turbine tower 15. An example of this configuration is shown in FIG.

[0064] In some examples, the method 400 may further include hoisting the first tower section 151 above the second tower section 152 and positioning the first tower section 151 relative to the second tower section 152 using a camera system attached to the first or second tower section 151, 152. Thus, the apparatus 100 may receive a signal including information from the camera system to move the shaft 110 from the retracted position to the extended position, or vice versa.

[0065] In an embodiment, the first and second holes 131, 141 may be centering holes, and the first and second flanges 130, 140 may further include fastening holes.

[0066] In another aspect, a method 500 is disclosed for erecting a wind turbine tower 15 including a plurality of tower sections 151, 152. Each tower section 151, 152 of the method 500 includes at least one mounting flange 130, 140. The method 500 includes, in block 501, substantially aligning the upper tower section 151 over the lower tower section 152 such that an upper mounting flange 140 of the lower tower section 152 is substantially aligned with a lower mounting flange 130 of the upper tower section 151, wherein one of the lower mounting flange 140 and the upper mounting flange 130 of each tower section 152, 151 carries an alignment device 100 having a shaft 110, the shaft 110 including a first pusher 115 and a second pusher 116. Further, the method 500 includes, in block 502, extending the shaft 110 of the aligning device 100 through a first hole 130 of one of the upper or lower mounting flanges 130, 140 and into a second hole 140 of the other of the upper or lower mounting flanges 130, 140, such that the first pusher 115 is positioned in the first hole 131 and the second pusher 116 is positioned in the second hole 141.

[0067] The method 500 also includes, in block 503, moving the first and second pushers 115, 116 radially outward to press against the inside of the first hole 131 and the inside of the second hole 141, respectively, to align the first hole 131 and the second hole 141.

[0068] The method 500 saves time during installation of the wind turbine tower sections because the alignment process is relatively simple. The flanges 130, 140, which may undergo geometric modifications during storage, can be easily matched without the need for on-site personnel to be present. Additionally, the method 500 can also reduce the time spent by the crane during connection of each tower section, thus reducing the overall cost of the assembly process.

[0069] In an embodiment, the positioning step at block 501 includes lifting the upper tower section 151 using a lifting device such as a crane, and while the crane substantially supports the upper tower section 151, an extension 502 of the shaft 110 and a radially outward movement 503 of the first and second pushers 115, 116 are performed.

[0070] In some embodiments, method 500 may include removing the crane after apparatus 100 aligns first hole 131 and second hole 141. In additional embodiments, method 500 may further include fastening upper and lower mounting flanges 130, 140 together. Fastening of the mounting flanges may occur after the crane is no longer lifting the tower section.

[0071] In some embodiments, the connection with the crane can be removed after the flanges of the tower sections are forced into contact with each other, i.e., after the shaft of the device is retracted such that the relative motion between the first flange and the shaft is greater than the relative motion between the second flange and the shaft.

[0072] In an embodiment, the aligning apparatus 100 is attached to the upper tower section 151 prior to lifting the upper tower section 151. Note that the apparatus 100 may be attached to the upper flange (from below) or the lower flange (from above) depending on the mounting preference relative to the adjacent tower sections.

[0073] In some examples, a camera system may be attached to the upper tower section 151 prior to lifting the upper tower section 151. The camera system may be used to aid in positioning the upper tower section 151 relative to adjacent tower sections. For example, it may be used to aid in positioning the upper tower section 151 relative to the lower tower section 152 and / or relative to a subsequent tower section located above the upper tower section 151.

[0074] It should be noted that the methods 400, 500 suitable for aligning the first hole 131 of the first flange 130 with the second hole 141 of the second flange 140, and vice versa, may include all the functionality of the apparatus 100.

[0075] This specification uses examples to disclose the teachings, including preferred embodiments, and to enable any person skilled in the art to practice the teachings, including making and using any devices or systems, and performing any methods incorporated therein. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be included in the claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not differ substantially from the language of the claims. Aspects from the various embodiments described, and other known equivalents to each such aspect, may be mixed and matched by those skilled in the art to construct additional embodiments and techniques according to the principles of this application. When reference signs related to the drawings are placed in parentheses in the claims, they are merely intended to improve the clarity of the claims, and should not be construed as limiting the scope of the claims. [Explanation of symbols]

[0076] 10: Wind turbine 12: Ground 14: Support system 15: Tower 16: Nacelle 18: Rotor 20: Hub 22: Rotor blade 23: Reference line 24: Blade root 25: Pitch angle 26: Load transfer area 28: Wind direction 30: Rotor shaft 32: Pitch system 34: Pitch axis 36: Wind turbine controller 38: Yaw axis 40: Processor 42: Generator 43: Communication module 44: Main shaft 46: Gearbox 48: High speed shaft 50: Coupling 52: Main frame 54: Decoupling support means 56: Yaw drive mechanism 58: Meteorological measurement system 60: Main forward support bearing 62: Aft support bearing 64: Drive train 66: Pitch assembly 68: Pitch drive system 70: Sensor 72: Pitch bearing 78: Pitch drive pinion 80: Pitch control system 84: Generator 86: Cavity 88: Inner surface 90: Transformer 100: Device 101: Base 103: Torque arm 110: Shaft 115: First pusher 116: Second pusher 130, 140: Mounting flange 131: First hole 141: Second hole 151, 152: Tower section

Claims

1. A device (100) for aligning the first hole (131) of the first flange (130) and the second hole (141) of the second flange (140), A base (101) configured to be attached to the first flange (130), A shaft (110) extending from the base (101), Including the first and second pushers (115, 116), The base (101) further includes an actuator assembly that acts on the shaft (110) and at least one of the first and second pushers (115, 116), The shaft (110) is configured to move between a retracted position and an extended position, and in the extended position, the shaft (110) extends from the first hole (131) into the second hole (141), The first pusher (115) is configured to be positioned within the first hole (131), The second pusher (116) is configured to be positioned within the second hole (141), When the shaft (110) is in the extended position, the first and second pushers (115, 116) are configured to move radially outward from the shaft (110) to apply pressure to the inner walls of the first and second holes (131, 141), respectively. The apparatus (100) is configured such that the first pusher (115) is further configured to slide along the inner wall of the first hole (131) and / or along the shaft (110), and the second pusher (116) is configured to be substantially fixed against the inner wall of the second hole (141) when the shaft (110) is moved from the extended position toward the retracted position, thereby facilitating relative motion between the first and second flanges (130, 140).

2. The apparatus (100) according to claim 1, wherein the first pusher (115) and the second pusher (116) include an outer surface, and the coefficient of friction between the outer surface of the first pusher (115) and the inner wall of the first hole (131) is lower than the coefficient of friction between the outer surface of the second pusher (116) and the inner wall of the second hole (141).

3. The apparatus (100) according to claim 1, wherein the base (101) comprises a rim for attaching the apparatus to the first flange (130).

4. The apparatus (100) according to claim 1, wherein at least one of the first and second pushers (115, 116) includes a pair of wedges facing each other in the diametrical direction.

5. A method (400) for aligning a first hole (131) of a first flange (130) with a second hole (141) of a second flange (140), The steps of providing the apparatus (100) according to any one of claims 1 to 4, Step (401) of attaching the base (101) of the device (100) to the first flange (130) such that the shaft (110) of the device (100) extends into the first hole (131) of the first flange (131), Step (402) is to extend the shaft (110) through the first hole (131) into the second hole (141) such that the first pusher (115) is positioned inside the first hole (130) and the second pusher (116) is positioned inside the second hole (141), The first and second pushers (115, 116) are moved radially outward from the shaft (110) (403), pressing against the inside of the first hole (131) and the inside of the second hole (141), respectively, to align the first hole (131) and the second hole (141), The steps include: retracting the shaft (110) of the device (100) such that the relative motion between the first flange (130) and the shaft (110) is greater than the relative motion between the second flange (140) and the shaft (110); Including methods (400).

6. The method according to claim 5 (400), wherein the step of retracting the shaft (110) of the device (100) includes the step of sliding the first pusher (115) along the inner wall of the first hole (131), or the step of sliding the first pusher (115) along the shaft (110).

7. The method according to claim 5 (400), wherein the first flange (130) is a lower mounting flange of the upper tower portion (151) of the wind turbine tower (15), and the second flange (140) is an upper mounting flange of the lower tower portion (152) of the wind turbine tower (15).

8. The method according to claim 5 (400), wherein the first and second holes (131, 141) are centering holes, and the first and second flanges (130, 140) further comprise fastening holes.

9. A step of using a lifting device to lift and position the upper tower section (151) substantially above the lower tower section (152) such that the upper mounting flange (140) of the lower tower section (152) is substantially aligned with the lower mounting flange (130) of the upper tower section (151), The method according to claim 7 (400), further comprising the steps of extending the shaft (110) (402) and moving the first and second pushers (115, 116) (403) while the lifting device substantially supports the upper tower section (151).

10. The method according to claim 9 (400), further comprising the step of removing the suspension after the device (100) has once aligned the first hole (131) and the second hole (141), the method then further comprising the step of fixing the first and second flanges (130, 140) together.

11. The method according to claim 9 (400), wherein the alignment device is attached to the upper tower before the upper tower is lifted.

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