Method for repairing shafts of wind turbines for wind power generation and shaft rotation device used therein

Abstract

To provide a shaft repair method which can favorably repair a shaft by simple equipment in a nacelle of a wind power generation windmill, and a shaft rotation method for use in the same.SOLUTION: In a carry-in process, repair equipment is carried into a nacelle 14. In a shaft separation process, a shaft 16 is separated by separating a second shaft part 16b from a first shaft part 16a. In a journal part exposure process, a journal part 22 held by a bearing 18 at the second shaft part 16b is exposed. In a buildup process, a buildup layer is formed on a surface of the journal part 22 at the second shaft part 16b while rotating only the second shaft part 16b without rotating the first shaft part 16a by using the repair equipment which is carried into the nacelle 14.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a shaft repair method for a wind turbine in which a shaft connected to a blade and a bearing that rotatably holds the shaft are housed in a hollow nacelle, and a shaft rotating device used therefor.

[0002] In a wind turbine for wind power generation, a blade that receives wind power is connected to a shaft, and a journal portion that is a part of the shaft is rotatably held by a bearing. In this type of wind turbine for wind power generation, the surface of the journal portion wears as the shaft rotates, and thus repair is performed as necessary.

[0003] On the other hand, a processing method of overlaying a metal corresponding to a welding material by melting the welding material has been conventionally known. For example, in Patent Document 1 below, laser cladding that irradiates a laser beam to melt a welding material and forms a cladding layer has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] From the standpoint of shortening delivery times and reducing costs, it is preferable to perform shaft repairs on-site. In wind turbines for power generation, various components or devices such as generators with bearings are housed in a hollow nacelle installed at a height of several tens of meters or more on the ground or offshore. Therefore, in order to perform shaft repairs on-site within the nacelle, it is important that the repairs can be carried out with simple, portable equipment. However, no technology has been proposed to date that allows for the satisfactory repair of such shafts with simple equipment. In other words, it has been difficult to repair shafts within the nacelle of wind turbines for power generation.

[0006] Therefore, conventionally, parts or equipment requiring repair had to be removed from the nacelle, transported, and repaired at a maintenance facility equipped for such repairs. As a result, repairs took a long time, and during that time, the wind turbine could not be operated. In addition, when removing large equipment such as generators from the nacelle, which is located at a high altitude, large-scale work using specialized cranes was required, resulting in high repair costs.

[0007] This invention has been made in view of the above circumstances, and aims to provide a shaft repair method and a shaft rotation device used therein that can repair the shaft well with simple equipment inside the nacelle of a wind turbine for wind power generation. [Means for solving the problem]

[0008] (1) The shaft repair method according to the present invention is a shaft repair method for a wind turbine for wind power generation, in which a shaft connected to a blade and a bearing that rotatably holds the shaft are housed in a hollow nacelle, and comprises a loading step, a shaft separation step, a journal portion exposure step, and a build-up step. The shaft includes a first shaft portion to which the blade is connected and a second shaft portion that is held by the bearing and is detachable from the first shaft portion. In the loading step, repair equipment is loaded into the nacelle. In the shaft separation step, the shaft is separated by detaching the second shaft portion from the first shaft portion. In the journal portion exposure step, the journal portion held by the bearing in the second shaft portion is exposed. In the build-up step, the shaft is repaired by using the repair equipment loaded into the nacelle, while rotating only the second shaft portion without rotating the first shaft portion, and forming a build-up layer on the surface of the journal portion in the second shaft portion.

[0009] With this configuration, the first and second shaft sections of the shaft can be separated, and a build-up layer can be formed on the surface of the journal section while the second shaft section rotates, without rotating the first shaft section to which the blades are attached. This allows repair work to be carried out by bringing only the minimum necessary repair equipment into the nacelle, enabling the shaft to be repaired effectively with simple equipment inside the nacelle of a wind turbine installed at a high altitude.

[0010] (2) The repair equipment may include a drive device for rotating the second shaft. In this case, the shaft repair method may further include a drive device connection step for connecting the drive device to the second shaft. In addition, in the build-up step, a build-up layer may be formed on the surface of the journal portion on the second shaft while the second shaft is rotated by the drive device.

[0011] With this configuration, a build-up layer can be formed on the surface of the journal section while the second shaft section is rotated by the drive unit. Therefore, the shaft can be easily repaired.

[0012] (3) The repair equipment may include a temporary bearing separate from the bearing. In this case, the shaft repair method may further include a temporary bearing mounting step in which the portion of the second shaft other than the journal portion is rotatably held by the temporary bearing, either directly or indirectly. In addition, in the build-up step, a build-up layer may be formed on the surface of the journal portion of the second shaft while the second shaft portion held by the temporary bearing is rotated.

[0013] With this configuration, the second shaft can be rotatably held by a temporary bearing. Furthermore, vibrations of the second shaft that occur during machining of the journal can be suppressed. Therefore, the shaft can be repaired with high precision.

[0014] (4) The repair equipment may include a cutting device for performing a cutting process on the surface of the second shaft. In this case, the shaft repair method may further include a cutting step to remove the worn portion on the surface of the journal by performing a cutting process on the surface of the journal on the second shaft using the cutting device while rotating the second shaft. In addition, in the build-up step, a build-up layer may be formed on the surface of the journal after the cutting step. In addition, after the build-up step, finishing work may be performed using the cutting device.

[0015] With this configuration, the shaft can be repaired so that the diameter of the second shaft portion is the same before and after the repair.

[0016] (5) In the build-up process, a build-up layer may be formed on the surface of the journal portion of the second shaft portion by thermal spraying a welding material.

[0017] With this configuration, a build-up layer corresponding to the welding material can be formed on the surface of the journal portion of the second shaft. By using thermal spraying, which produces less sparks, the shaft can be repaired safely.

[0018] (6) In the cladding process, a cladding layer may be formed on the surface of the journal portion of the second shaft portion by laser cladding.

[0019] With this configuration, a build-up layer can be formed on the surface of the journal portion of the second shaft by laser cladding. By using laser cladding, which has minimal thermal effects, the shaft can be repaired safely.

[0020] (7) The shaft rotating device according to the present invention is a shaft rotating device used in the shaft repair method, and comprises a temporary bearing, a support base, and a drive device. The temporary bearing is provided separately from the bearing and holds the second shaft portion so that it can rotate directly or indirectly. The support base supports the temporary bearing. The drive device rotates the second shaft portion.

[0021] With this configuration, only the second shaft portion of the shaft can be rotated independently by the drive unit. Since a small device is sufficient for such a drive unit, the shaft can be easily repaired with simple equipment inside the nacelle of a wind turbine.

[0022] (8) The second shaft portion constitutes the rotor of a power generation device provided on the wind turbine for wind power generation, and the support base may be connected to the power generation device.

[0023] This configuration allows for improved positional accuracy of the support base relative to the temporary bearing. Furthermore, it can further suppress vibrations in the second shaft section that occur during machining of the journal section. In other words, it improves the precision of machining the journal section. Moreover, it prevents the support base from vibrating or moving due to the excitation force generated by machining the journal section. Therefore, the shaft can be repaired with high precision.

[0024] (9) The shaft rotation device may further include a jack device for pushing up the power generation device upward, and a fixture for fixing the power generation device pushed up by the jack device in a state of pressing it downward.

[0025] According to such a configuration, the shaking of the power generation device during machining of the journal portion is suppressed by the forces acting in opposite directions on the jack device and the fixture. Therefore, the accuracy of machining of the journal portion can be improved.

Effect of the Invention

[0026] According to the present invention, in the nacelle of a wind turbine for wind power generation, the shaft can be repaired well with simple equipment.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic diagram showing an example of a wind turbine for wind power generation of the first embodiment. [Figure 2] It is a flowchart showing an example of a method for repairing a shaft of the first embodiment. [Figure 3] It is a perspective view for explaining the temporary bearing mounting process of the first embodiment. [Figure 4] It is a cross-sectional view for explaining the temporary bearing mounting process of the first embodiment. [Figure 5] It is a schematic diagram for explaining the driving device connection process of the first embodiment. [Figure 6] It is a schematic diagram for explaining the fixing process of the first embodiment. [Figure 7] It is a perspective view showing an example of a cutting device of the first embodiment. [Figure 8] It is a schematic diagram showing an example of the rear surface of the fixture of the first embodiment. [Figure 9] It is a schematic diagram showing a part of an example of a layer forming device of the first embodiment. [Figure 10] It is a schematic diagram showing a part of another example of the layer forming device of the first embodiment. [Figure 11]This is a schematic diagram showing some of yet other examples of the layering apparatus of the first embodiment. [Figure 12] This is a block diagram showing an example of a thermal spraying system according to the first embodiment. [Modes for carrying out the invention]

[0028] 1. Overview of wind turbines for wind power generation Figure 1 is a schematic diagram showing an example of a wind turbine 10 for wind power generation according to the first embodiment. As shown in Figure 1, the wind turbine 10 for wind power generation comprises blades 12, a nacelle 14, a shaft 16, a power generation device 20, etc. The power generation device 20 has bearings 18. Although the numbering is omitted in Figure 1, the wind turbine 10 for wind power generation also comprises bearings other than bearings 18, brakes, a speed increaser, a coupling, etc.

[0029] As shown in Figure 1, the shaft 16 and the power generation device 20 are housed within a hollow nacelle 14. The hub 13, to which the blades 12 are attached, is connected to the shaft 16.

[0030] The shaft 16 includes a first shaft portion 16a and a second shaft portion 16b, which are connected to each other. Specifically, the rear end of the first shaft portion 16a and the front end of the second shaft portion 16b are connected to each other. In this specification, "front" means the direction in which the blade 12 is located, and "rear" means the opposite direction from "front". That is, the front-rear direction is the same direction as the axial direction of the shaft 16.

[0031] Furthermore, the first shaft portion 16a and the second shaft portion 16b can be separated from each other. That is, the second shaft portion 16b can be connected to and separated (attached to and detached from) the first shaft portion 16a.

[0032] When the first shaft portion 16a and the second shaft portion 16b are connected, the blade 12, the first shaft portion 16a, and the second shaft portion 16b rotate as a single unit.

[0033] The bearing 18 is a component of the power generation device 20 and is provided to rotatably hold the second shaft portion 16b. For example, a general-purpose bearing (such as a rolling bearing) is used as the bearing 18.

[0034] The power generation device 20 is provided to generate electricity by utilizing the rotation of the second shaft portion 16b. That is, at least the second shaft portion 16b of the shaft 16 constitutes the rotor of the power generation device 20.

[0035] In such a wind turbine 10, the blades 12 are exposed to wind, causing the shaft 16 to rotate and generating electricity with the power generation device 20. In this case, the surface of the journal portion 22, which is the part of the second shaft portion 16b of the shaft 16 that is held by the bearing 18, wears down. The outer diameter of the journal portion 22 is 100 to 300 mm, for example, 150 mm. The material of the shaft 16 is carbon steel (for example, S45C) or structural alloy steel (for example, SCM).

[0036] 2. How to repair the shaft Figure 2 is a flowchart illustrating an example of a repair method for the shaft 16 according to the first embodiment. In the first embodiment, when repairing the shaft 16, a preparation step and a processing step are performed. The preparation step is a process related to preparing for processing the journal portion 22. The processing step is a process related to processing the journal portion 22. First, the preparation step will be described.

[0037] The preparation process includes the loading process (step S1), the shaft separation process (step S2), the journal section exposure process (step S3), the temporary bearing installation process (step S4), the drive unit connection process (step S5), and the fixing process (step S6), etc.

[0038] The loading process (step S1) is the process of loading repair equipment into the nacelle 14. Specifically, repair equipment refers to devices, materials, and tools used for repairing the shaft 16.

[0039] The shaft separation process (step S2) is a process of separating the first shaft portion 16a and the second shaft portion 16b of the shaft 16. The first shaft portion 16a and the second shaft portion 16b are connected, for example, by a coupling. In the shaft separation process, the fixing state by the fixing device is released and the second shaft portion 16b is detached from the first shaft portion 16a, thereby separating the shaft 16.

[0040] The journal exposure step (step S3) is the process of exposing the journal portion 22. In other words, the journal exposure step is also the process of removing the bearing 18.

[0041] The temporary bearing installation step (step S4) is a step in which the portion of the second shaft portion 16b other than the journal portion 22 is rotatably held by the temporary bearing 24, either directly or indirectly. Figure 3 is a perspective view illustrating the temporary bearing installation step of the first embodiment. Figure 4 is a cross-sectional view illustrating the temporary bearing installation step of the first embodiment. Figure 3 also shows an example of the front side of the power generation device 20, and Figure 4 shows an example of the area around the second shaft portion 16b.

[0042] Note that in Figures 3 and 4, the bearing 18 and the bearing housing (not shown) have already been removed. Also, in Figure 4, the removed bearing 18 is represented by a dashed line.

[0043] Once the temporary bearing installation process is performed, a temporary bearing 24, separate from the bearing 18, holds the second shaft portion 16b rotatably, either directly or indirectly, similar to the bearing 18. For example, a general-purpose bearing (such as a rolling bearing) can be used as the temporary bearing 24.

[0044] In the examples shown in Figures 3 and 4, the temporary bearing 24 holds the second shaft portion 16b via a connecting shaft 26. The connecting shaft 26 is a member for extending the second shaft portion 16b in the front-rear direction and is connected to the second shaft portion 16b. In other words, the connecting shaft 26 connected to the second shaft portion 16b is made rotatable integrally with the second shaft portion 16b. Also, in Figures 3 and 4, the connecting shaft 26 connected to the second shaft portion 16b is held by the temporary bearing 24. Thus, in this embodiment, the portion of the second shaft portion 16b other than the journal portion 22 is indirectly held by the temporary bearing 24 via the connecting shaft 26. However, the connecting shaft 26 may be omitted, and the portion of the second shaft portion 16b other than the journal portion 22 may be directly held by the temporary bearing 24.

[0045] Furthermore, the temporary bearing 24 is supported by a temporary bearing base 28. The temporary bearing base 28 is a base for supporting the temporary bearing 24 and is installed on the floor of the nacelle 14.

[0046] Therefore, when the temporary bearing installation process is performed, the vibration of the second shaft portion 16b that occurs during machining of the journal portion 22 is suppressed by the temporary bearing 24 and the temporary bearing base 28. In other words, the machining accuracy can be improved when machining the journal portion 22.

[0047] Furthermore, during the temporary bearing installation process, the temporary bearing base 28 may be connected to the power generation device 20, specifically to the front frame of the power generation device 20. In the example shown in Figure 3, the temporary bearing base 28 is connected to the front frame of the power generation device 20 via a mounting fixture 52 and a plurality of rod-shaped connecting members 30, which will be described later.

[0048] In this way, when the temporary bearing base 28 is connected to the power generation device 20, the accuracy of the position of the temporary bearing base 28 relative to the temporary bearing 24 can be improved.

[0049] Furthermore, in this case, since the temporary bearing base 28 is fixed to the power generation device 20, vibrations of the second shaft portion 16b that occur during machining of the journal portion 22 can be further suppressed. In other words, the machining accuracy can be further improved when machining the journal portion 22.

[0050] Furthermore, in this case, the vibration force generated by the machining of the journal portion 22 can prevent the temporary bearing base 28 from vibrating or moving.

[0051] The drive unit connection step (step S5) is the process of connecting the drive unit 32 to the second shaft portion 16b. Figure 5 is a schematic diagram illustrating the drive unit connection step of the first embodiment. Figure 5 also shows an example of the rear side of the power generation device 20.

[0052] When the drive unit coupling process is performed, the drive unit 32 is fixed onto the drive unit base 31 and connected to the second shaft 16b. The drive unit 32 is provided to supply rotational force to the second shaft 16b. For example, a general-purpose motor is used as the drive unit 32. The drive unit 32 is also capable of variable speed drive by an inverter device (not shown). The drive unit base 31 is a base that supports the drive unit 32 and is fixed to the rear frame of the power generation device 20.

[0053] In the example shown in Figure 5, the drive unit 32 is connected to the second shaft portion 16b via a transmission mechanism 34 for transmitting rotational force. The transmission mechanism 34 is a well-known mechanism for transmitting rotational force generated on one side to the other.

[0054] The transmission mechanism 34 may include, for example, rotating members that rotate integrally with the shaft, such as sprockets and pulleys. The transmission mechanism 34 may also include members that transmit the rotation of one rotating member to the other, such as belts and chains.

[0055] Based on these considerations, once the drive unit connection process is performed, the rotational force generated by the drive unit 32 is transmitted to the second shaft portion 16b via the transmission mechanism 34, making it possible to rotate the second shaft portion 16b.

[0056] The fixing step (step S6) is a process of fixing the power generation device 20 in a state where it is pushed up so as to separate it from the power generation device base 36, while pressing the pushed-up power generation device 20 toward the power generation device base 36. Note that the fixing step (step S6) may be performed before the temporary bearing installation step (step S4). Figure 6 is a schematic diagram illustrating the fixing step of the first embodiment. Figure 6 also shows an example of the power generation device 20 viewed perpendicular to its axis.

[0057] As shown in Figure 6, the power generation device 20 is fixed to the power generation device base 36 via a vibration-damping member 38. The power generation device base 36 is a base that supports the power generation device 20. The vibration-damping member 38 is a member that absorbs vibrations generated when the power generation device 20 is in operation, and is made of an elastic material such as rubber.

[0058] Once the fixing process is completed, the jacking device 40 pushes up the power generator 20 so that it is separated from the power generator base 36. For example, the jacking device 40 may include jack bolts and general-purpose jacks.

[0059] In this way, when the power generation device 20 is pushed up, the deflection of the vibration-damping member 38 is eliminated, and the shaking of the power generation device 20 caused by the vibration-damping member 38 during processing of the journal portion 22 can be suppressed.

[0060] Furthermore, once the fixing process is carried out, the power generation device 20 is pressed toward the power generation device base 36 by the fixing device 42 and fixed in place. As the fixing device 42, for example, tools for pulling one member toward the other, such as a chain block and a rope, may be used. In the example shown in Figure 6, the power generation device 20 is fixed by the fixing device 42 in such a way that it is pulled toward the power generation device base 36, that is, pressed toward it.

[0061] Based on these factors, the opposing forces acting on the jacking device 40 and the fixing device 42 suppress the shaking of the power generation device 20 when machining the journal portion 22. In other words, the fixing process improves the machining accuracy when machining the journal portion 22.

[0062] In the first embodiment, once the preparation steps (steps S1 to S6) are performed, the second shaft portion 16b can be rotated by the drive device 32 without rotating the first shaft portion 16a to which the blade 12 is connected. In other words, the temporary bearing 24, temporary bearing base 28, drive device 32, jack device 40, and fixing device 42, etc., constitute a shaft rotation device that rotates the second shaft portion 16b independently.

[0063] Of the preparation steps, the loading step (step S1) is performed first, but the order in which the shaft separation step (step S2), journal section exposure step (step S3), temporary bearing installation step (step S4), drive unit connection step (step S5), and fixing step (step S6) are performed is not particularly limited. Next, the machining steps will be described.

[0064] In the first embodiment, the machining process is performed after the preparatory machining is carried out. The machining process, as described above, is a process relating to machining applied to the journal portion 22, and includes a cutting process (step S7), a build-up process (step S8), and a finishing process (step S9).

[0065] The cutting process (step S7) is a process in which the surface of the journal portion 22 is cut while the second shaft portion 16b is rotated, thereby removing the worn portion on the surface of the journal portion 22.

[0066] In the cutting process, a cutting device 44 and a mounting fixture 52 are used. The cutting device 44 is a device for performing a cutting process on the surface of the journal portion 22 of the second shaft portion 16b. The mounting fixture 52 is a component for attaching the cutting device 44 to the frame plate 23 of the power generation device 20.

[0067] Figure 7 is a perspective view showing an example of a cutting device 44 of the first embodiment. Figure 8 is a schematic diagram showing an example of the rear side of a mounting fixture 52 of the first embodiment.

[0068] The cutting device 44 includes a flat plate 46, a feed mechanism 48, and a cutting section 50, etc. The feed mechanism 48 and the cutting section 50 are provided on the flat plate 46.

[0069] The feed mechanism 48 is a mechanism for displacing the cutting section 50 in the front-rear direction and along the radial direction of the second shaft section 16b. The feed mechanism 48 is a well-known mechanism that displaces the position of other members in response to the rotation or other operation of a predetermined member.

[0070] The feed mechanism 48 consists of a device for displacing the cutting section 50 in the front-rear direction and a device for displacing the cutting section 50 along the radial direction of the second shaft section 16b, and these devices are further composed of components such as a rack and pinion, a motor, and a handle. The cutting section 50 includes a blade for cutting metal and a base for fixing the blade.

[0071] The mounting fixture 52 comprises a fixing plate 52a and a mounting plate 52b. The fixing plate 52a is a plate on which the cutting device 44 is placed and fixed. The mounting plate 52b is a plate for attaching the cutting device 44, which is fixed to the fixing plate 52a, to the frame plate 23 of the power generation device 20. The fixing plate 52a is fixed to the front surface of the mounting plate 52b.

[0072] Furthermore, as shown in Figure 8, a protrusion 56 is formed on the rear surface of the mounting plate 52b, and this protrusion 56 is shaped to conform to the inner surface that forms the inner circumferential surface of the frame plate 23 of the power generation device 20.

[0073] In the cutting process, the cutting device 44 is fixed to the mounting fixture 52 and then attached to the power generation device 20 such that the protrusion 56 abuts against the inner circumferential surface of the frame plate 23 of the power generation device 20. When the cutting device 44 is attached to the frame plate 23 of the power generation device 20 via the mounting fixture 52, it is preferable that the protrusion 56 catches on the inner circumferential surface of the frame plate 23 due to gravity and is attached and fixed in place.

[0074] With such a cutting device 44 and mounting fixture 52, the cutting device 44 can be positioned near the frame plate 23 of the power generation device 20, and cutting can be performed on the surface of the journal portion 22 while rotating the second shaft portion 16b. The cutting device 44 may be integrally configured with the mounting fixture 52. That is, the cutting device 44 may include the mounting fixture 52.

[0075] Furthermore, in the first embodiment, as shown in Figure 7, the adjustment plate 58 may be sandwiched between the ends of the flat plate 46 and the fixed plate 52a, and then the flat plate 46 may be fixed to the fixed plate 52a. When the adjustment plate 58 is sandwiched between the flat plate 46 and the fixed plate 52a, the angle between the flat plate 46 and the fixed plate 52a is adjusted according to the thickness of the adjustment plate 58. In other words, by sandwiching the adjustment plate 58 between the flat plate 46 and the fixed plate 52a, the parallelism between the second shaft portion 16b and the cutting portion 50 can be adjusted. The adjustment plate 58 is a small, thin plate.

[0076] The build-up process (step S8) is a process of forming a build-up layer on the surface of the journal portion 22 of the second shaft portion 16b while rotating the second shaft portion 16b. Since the first shaft portion 16a and the second shaft portion 16b of the shaft 16 are separated by the shaft separation process (step S2), in the build-up process, the build-up layer can be formed by rotating only the second shaft portion 16b without rotating the first shaft portion 16a to which the blade 12 is connected.

[0077] In the cladding process, a layer forming device 80 is used. In the cladding process, the second shaft portion 16b is rotated at a constant speed by the drive device 32. The layer forming device 80 is also moved at a constant speed along the axial direction (front-back direction) of the second shaft portion 16b. This makes it possible to form a uniform cladding layer over a wide area of ​​the surface of the journal portion 22. The layer forming device 80 is, for example, a thermal spraying device that corresponds to cladding spraying. Cladding spraying is a thermal spraying method that uses well-known thermal spraying methods such as gas spraying and electric spraying to build up a metal base material by melting and spraying a metal molten material, and is distinguished from laser cladding, which melts the molten material with a laser.

[0078] Gas-powered spraying is a method that uses the heat generated when a flammable gas burns to spray the molten material. Electric-powered spraying is a method that uses the heat source of an arc discharge to spray the molten material.

[0079] As the layer-forming apparatus 80, for example, a thermal spraying apparatus compatible with flame spraying is used. When a flame spraying apparatus is used as the layer-forming apparatus 80, the shape of the welding material supplied to the layer-forming apparatus 80 is either powder or wire.

[0080] Figure 9 is a schematic diagram showing a part of an example of a layer forming apparatus 80 of the first embodiment. Figure 9 also shows a flame spray type layer forming apparatus 80 using a linear welding material (linear welding material) 82. In Figure 9, the linear welding material 82 is supplied to the layer forming apparatus 80 together with compressed air, combustion gas, and oxygen.

[0081] In the layer forming apparatus 80 shown in Figure 9, a combustion flame 86 is formed by combustion gas and oxygen injected from the nozzle 84, and the linear welding material 82 is melted by this combustion flame 86. Furthermore, in the layer forming apparatus 80 shown in Figure 9, compressed air is injected from the nozzle 84 toward the surface of the journal portion 22.

[0082] Therefore, in the layering apparatus 80 of Figure 9, the linear welding material 82, which is melted by the combustion flame 86, is sprayed from the nozzle 84 toward the surface of the journal portion 22 together with compressed air. When the linear welding material 82 is sprayed toward the surface of the journal portion 22 in this way, the metal corresponding to the linear welding material 82 is built up on the surface of the journal portion 22.

[0083] Figure 10 is a schematic diagram showing some other examples of the layer forming apparatus 80 of the first embodiment. Figure 10 also shows a flame spray type layer forming apparatus 80 using powdered welding material 88. In Figure 10, the layer forming apparatus 80 is supplied with the powdered welding material 88 along with a gas (carrier gas) for injecting the powdered welding material 88 from a nozzle 90. Also in Figure 10, the layer forming apparatus 80 is supplied with combustion gas along with oxygen.

[0084] In the layer forming apparatus 80 shown in Figure 10, a combustion flame 92 is formed by combustion gas and oxygen injected from the nozzle 90. Also in the layer forming apparatus 80 shown in Figure 10, powdered welding material 88 is injected together with a carrier gas from the nozzle 90 toward the surface of the journal portion 22.

[0085] Therefore, in the layering apparatus 80 of Figure 10, the powdered welding material 88 sprayed from the nozzle 90 toward the surface of the journal portion 22 is melted as it passes through the combustion flame 92. In this way, when the powdered welding material 88 is sprayed toward the surface of the journal portion 22, the metal corresponding to the powdered welding material 88 is built up on the surface of the journal portion 22.

[0086] Figure 11 is a schematic diagram showing yet another example of the layering apparatus 80 of the first embodiment. Figure 11 also shows a laser cladding type layering apparatus 80.

[0087] In the layer-forming apparatus 80 shown in Figure 11, powdered welding material 96 is sprayed from the nozzle 94 toward the surface of the journal portion 22 along with a carrier gas. In the layer-forming apparatus 80 shown in Figure 11, the powdered welding material 96 is sprayed approximately perpendicular to the surface of the journal portion 22.

[0088] Furthermore, in the layering apparatus 80 shown in Figure 11, multiple laser beams 98 are continuously irradiated from multiple directions toward the surface of the journal portion 22. Each laser beam 98 is irradiated obliquely from the outside relative to the ejection direction of the powdered welding material 96, gradually approaching the ejection direction, and is focused at the same irradiation position 100. The irradiation position 100 is on or away from the surface of the journal portion 22.

[0089] Therefore, in the layering apparatus 80 of Figure 11, the powdered welding material 96 is melted as it passes through the irradiation position 100. When the powdered welding material 96 is melted in this way, the metal corresponding to the powdered welding material 96 is deposited on the surface of the journal portion 22. However, the laser may be irradiated approximately perpendicular to the surface of the journal portion 22, and the powdered welding material 96 may be sprayed toward the surface of the journal portion 22 from multiple directions.

[0090] In addition to the cutting process (step S7) and the build-up process (step S8), the processing steps may also include a blasting process. The blasting process is performed between the cutting process and the build-up process and involves blasting the surface of the journal portion 22 with metal particles or ceramic particles to roughen the surface. The blasting process is performed only when using a flame spraying type or arc spraying type layer formation apparatus 80, and may be omitted when using a laser cladding type layer formation apparatus 80.

[0091] The finishing process (step S9) is performed after the build-up process and is a process to smooth the surface of the build-up layer and finish it to a predetermined shape and dimensions. In the finishing process, the build-up layer is cut and finished using a cutting device 44. In addition to cutting, polishing may also be performed.

[0092] In the wind turbine 10 for wind power generation, the nacelle 14 is located at a high elevation, and the space inside the nacelle 14 is narrow. Furthermore, the formation of the build-up layer in the build-up process is performed by workers using a layer-forming device 80. Considering ease of transport and the reduction of spark scattering associated with thermal spraying, in the first embodiment, it is preferable to use a flame-type thermal spraying device using linear thermal material as the layer-forming device 80.

[0093] Figure 12 is a block diagram showing an example of the thermal spray system 120 of the first embodiment. In Figure 12, the thermal spray system 120 corresponds to a flame spray type layer forming apparatus 80 that uses a linear thermal material.

[0094] As shown in Figure 12, the thermal spraying system 120 includes an air supply unit 122, an oxygen storage unit 124, a combustion gas storage unit 126, a flow rate control unit 128, and a layer forming device 80, etc. The air supply unit 122, the oxygen storage unit 124, and the combustion gas storage unit 126 are each connected to the layer forming device 80 by pipes via the flow rate control unit 128.

[0095] The air supply unit 122 is provided to supply compressed air. A general-purpose compressor is used as the air supply unit 122. The oxygen storage unit 124 is a cylinder for storing oxygen. The combustion gas storage unit 126 is a cylinder for storing combustion gas.

[0096] The flow control unit 128 is a control unit for adjusting the flow rates of compressed air, oxygen, and combustion gas. In other words, the layer forming apparatus 80 is supplied with compressed air, oxygen, and combustion gas, each with adjusted flow rates. In addition, as shown in Figure 12, the layer forming apparatus 80 is supplied with a welding material separately from the compressed air, oxygen, and combustion gas.

[0097] With such a thermal spraying system 120, a build-up layer can be formed on the surface of the journal portion 22 by at least bringing the layer forming device 80 into the nacelle 14. The layer forming device 80 is, for example, composed of a gun-shaped thermal spray gun, which can be easily carried by hand into the nacelle 14 and used for thermal spraying.

[0098] In the first embodiment, when the machining process is performed, the surface of the journal portion 22 is repaired. In the machining process, the build-up process is performed after the cutting process, and the finishing process is performed after the build-up process. In other words, the machining process makes it possible to repair the shaft 16 so that the diameter of the second shaft portion 16b is the same before and after the repair of the shaft 16.

[0099] Furthermore, according to the first embodiment, the shaft 16 can be easily repaired with simple equipment inside the nacelle 14 of the wind turbine 10 for wind power generation. [Explanation of Symbols]

[0100] 10 Wind turbines for wind power generation 12 blades 14 Nacer 16 shafts 16a First shaft section 16b 2nd shaft part 18 bearings 20 Power generation equipment 22 Journal Section 24 Temporary bearing 28 Temporary bearing support base 32 Drive unit 40 Jacking device 42 Fixtures 44 Cutting equipment

Claims

1. A shaft repair method for a wind turbine for wind power generation, in which a shaft connected to blades and a bearing that rotatably holds the shaft are housed in a hollow nacelle, comprising the steps of: the shaft includes a first shaft portion to which the blade is connected, and a second shaft portion that is held by the bearing and is detachable from the first shaft portion, a carrying-in process of carrying repair equipment into the nacelle; a shaft separating step of separating the shaft by separating the second shaft portion from the first shaft portion; a journal portion exposing step of exposing a journal portion held by the bearing in the second shaft portion; and a build-up process for repairing the shaft by using repair equipment brought into the nacelle to form a build-up layer on the surface of the journal portion of the second shaft portion while rotating only the second shaft portion without rotating the first shaft portion.

2. the repair equipment includes a drive device for rotating the second shaft portion; a drive unit connecting step of connecting the drive unit to the second shaft portion, 2. The shaft repair method according to claim 1, wherein in the build-up process, a build-up layer is formed on the surface of the journal portion of the second shaft portion while the second shaft portion is rotated by the drive device.

3. the repair equipment includes a temporary bearing separate from the bearing; a temporary bearing mounting step of directly or indirectly holding a portion of the second shaft portion other than the journal portion so that the portion is rotatable by the temporary bearing, 3. A shaft repair method according to claim 1, wherein in the build-up process, a build-up layer is formed on the surface of the journal portion of the second shaft portion while rotating the second shaft portion held by the temporary bearing.

4. the repair equipment includes a cutting device for performing a cutting process on a surface of the second shaft portion; a cutting step of removing worn portions on the surface of the journal portion by using the cutting device to perform a cutting process on the surface of the journal portion of the second shaft portion while rotating the second shaft portion; 4. The shaft repair method according to claim 1, wherein the overlay step forms an overlay layer on the surface of the journal portion after the cutting step.

5. A shaft repair method according to any one of claims 1 to 4, characterized in that in the build-up process, a build-up layer is formed on the surface of the journal portion of the second shaft portion by thermally spraying a melting material.

6. A shaft repair method according to any one of claims 1 to 4, characterized in that in the cladding step, a cladding layer is formed on the surface of the journal portion of the second shaft portion by laser cladding.

7. A shaft rotating device used in the shaft repair method according to any one of claims 1 to 6, a temporary bearing provided separately from the bearing and configured to directly or indirectly rotatably hold the second shaft portion; a support base that supports the temporary bearing; a drive unit for rotating the second shaft portion.

8. the second shaft portion constitutes a rotor of a power generating device provided in the wind turbine for wind power generation, The shaft rotating device according to claim 7 , wherein the support base is connected to the power generating device.

9. a jack device for pushing the power generation device upward; 9. The shaft rotating device according to claim 7, further comprising a fixture that fixes the power generating device, which is pushed up by the jack device, in a state where the power generating device is pressed downward.

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