A bolt extension tool for bolt pre-tightening force of a wind power blade and a method of using the same

Abstract

The application relates to a bolt extension tool for bolt pre-tightening force of a wind power blade and a use method thereof. The bolt extension tool comprises a tool body and a boss. The tool body is a cylindrical metal block. An outer circumferential surface of the tool body is provided with an outer surface thread. One end of the tool body is provided with an inner cylindrical end surface, and the other end is provided with an outer cylindrical end surface. The boss is coaxially fixedly connected to the inner cylindrical end surface. The boss is used for radial rotation-stopping cooperation with a recess hole arranged on a bolt end surface of a blade root bolt. The boss is made of magnet. The diameter of the tool body is the same as the diameter of the bolt end surface of the blade root bolt. The bolt extension tool has the advantages of simple structure, low cost and strong universality. The bolt extension tool can be used for applying pre-tightening force to blade root bolts of different types of wind power generators. The bolt extension tool helps to reduce the overall length of the blade root bolt, thereby reducing the material cost of the bolt, and is also beneficial to the optimization design of a hub web.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine blade installation technology of non-metallic composite materials, and specifically relates to a bolt extension tool for pre-tightening wind turbine blade bolts and its usage method. Background Technology

[0002] In recent years, grid parity for large-megawatt wind turbines has become a development trend in the wind power industry. Turbine manufacturers and component suppliers are implementing cost reduction measures in various aspects, including design, raw material selection, and process optimization. Large-megawatt wind turbine blades are connected to the wind turbine's pitch bearing and hub via root bolts. The end of the root bolt extending beyond the pitch bearing is secured by a hexagonal nut and washer, and a hydraulic tensioner applies preload to the root bolt to ensure safe blade operation. To apply preload to the root bolt using the hydraulic tensioner, the root bolt typically needs to extend 8-10 threads beyond the hexagonal nut's end face. However, the portion of the root bolt extending beyond the hexagonal nut is detrimental to the hub's optimized design. Therefore, a significant distance needs to be maintained between the hub web and the root bolt end face to prevent interference between the root bolt and the hub web when the wind turbine blades adjust their pitch. The portion of the blade root bolt extending beyond the hexagonal nut is mainly used to apply preload to the blade root bolt and has no impact on the operation of the wind turbine. Reducing the length of the blade root bolt extending beyond the hexagonal nut can not only lower the raw material cost of the blade bolts, but also reduce the distance between the end face of the blade root bolt and the hub web, which is beneficial to the hub design. Summary of the Invention

[0003] To address the problem that a hydraulic tensioner cannot be used to apply preload to the blade root bolt when the extension of the blade root bolt beyond the hexagonal nut is too short, this invention provides a bolt extension fixture for wind turbine blade bolt preload and its usage method.

[0004] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a bolt extension fixture for wind turbine blade bolt preload is proposed. The bolt extension fixture includes a fixture body and a boss. The fixture body is a cylindrical metal block with an outer surface thread on its outer circumferential surface. One end of the fixture body has an inner cylindrical end face, and the other end has an outer cylindrical end face. The boss is coaxially fixedly connected to the inner cylindrical end face. The boss is used for radial anti-rotation engagement with a recessed hole on the bolt end face of the blade root bolt. The boss is made of magnet. The diameter of the fixture body is the same as the diameter of the bolt end face of the blade root bolt. Thus, after the bolt extension fixture is installed and adsorbed onto the end of the blade root bolt, the outer surface of the bolt extension fixture and the outer surface of the blade root bolt are on the same cylindrical surface. Furthermore, the outer surface thread is continuous with the outer thread of the blade root bolt and can engage with the inner wall thread of the puller in existing hydraulic tensioners.

[0005] Furthermore, one end of the tooling body is provided with an edge protrusion, and the other end is provided with a tooling edge chamfer. The edge of the inner cylindrical end face and the edge protrusion are integrally machined, and the edge of the outer cylindrical end face is the tooling edge chamfer. The edge protrusion is used to cooperate with the edge chamfer provided on the end face of the leaf root bolt to ensure that the outer surface of the bolt and the outer surface of the bolt extension tooling are on the same cylindrical surface.

[0006] Furthermore, the axial length of the boss is less than or equal to the axial depth of the concave hole.

[0007] Furthermore, the boss is a hexagonal prism with a radial cross-section of hexagonal, and correspondingly, the concave hole is an inner hexagonal.

[0008] Furthermore, the boss is welded to the inner cylindrical end face of the tooling body.

[0009] Furthermore, it also includes a bolt extension tool separator for pulling the bolt extension tool from the leaf root bolt. The bolt extension tool separator includes a separator body, which is a hollow cylindrical structure with one end face closed (called the closed end) and the other end face open (called the open end). The inner diameter of the separator body is the same as the outer diameter of the tool body of the bolt extension tool. The inner surface of the separator body is provided with an internal thread that mates with the external thread on the tool body. At least one pull ring is provided on the closed end.

[0010] Furthermore, the diameter of the tooling body of the bolt extension fixture and the diameter of the bolt end face of the leaf root bolt are the same and are not limited to φ36mm, φ39mm or φ45mm.

[0011] The above-mentioned method for using a bolt extension fixture for preload of wind turbine blade bolts includes the following steps:

[0012] Step 1: The outer ring bolt holes of the pitch bearing are connected to the hub flange holes of the hub flange by bolts; the wind turbine blades are connected to the inner ring bolt holes of the pitch bearing by blade root bolts; the washers and hexagonal nuts are screwed from the bolt end face of the blade root bolts to the inner ring of the pitch bearing in sequence; after the hexagonal nuts are tightened, the bolt end face extends beyond the hexagonal nut end face.

[0013] Step 2: Insert the boss of the bolt extension fixture into the hexagonal socket of the leaf root bolt until the edge protrusion of the bolt extension fixture matches the chamfered edge of the bolt end face of the leaf root bolt.

[0014] Step 3: Apply preload to the leaf root bolt using a hydraulic tensioner, which includes a support sleeve, a puller, and a lever.

[0015] The process of applying preload to the blade root bolt using a hydraulic tensioner is as follows: First, the support sleeve is placed on the blade root bolt and covers the hexagonal nut through the process hole on the web of the hub. Then, the tensioner is rotated and placed on the bolt extension fixture and the blade root bolt. Next, the hydraulic tensioner is pressurized to lengthen the blade root bolt. The hexagonal nut is rotated using a lever to make it tightly adhere to the inner ring of the pitch bearing and be in a locked state. Finally, the pressure is released to separate the tensioner from the bolt extension fixture and the blade root bolt. The support sleeve is then removed, completing the application of preload to one blade root bolt.

[0016] Step 4: Use the bolt extension tool separator to separate the bolt extension tool from the blade root bolt;

[0017] Step 5: Repeat steps 2, 3 and 4 to install the bolt extension fixture onto the other leaf root bolts and apply preload.

[0018] Furthermore, in step 2, when the edge protrusion mates with the edge chamfer of the bolt end face, it is considered that the bolt extension fixture and the leaf root bolt are in place. At this time, the outer surface thread of the bolt extension fixture is continuous with the outer thread of the leaf root bolt.

[0019] Furthermore, in step 4, the open end of the bolt extension tool separator is screwed into the bolt extension tool, and the bolt extension tool is separated from the blade root bolt by pulling the pull ring on the bolt extension tool separator away from the blade root bolt.

[0020] By employing the above technical solution, the beneficial effects of the present invention are:

[0021] 1) The bolt extension tooling of the present invention can reduce the overall length of the blade root bolt design, reduce the material cost of the blade root bolt, and also help optimize the design of the wind turbine hub;

[0022] 2) With the bolt extension fixture of the present invention, the required preload force of the leaf root bolt can be applied by the hydraulic tensioner when the hexagonal nut protrudes shortly from the leaf root bolt.

[0023] 3) The bolt extension fixture proposed in this invention has a simple structure and low cost. It can be used to apply preload to the blade root bolts of different types of wind turbines. Moreover, for different types of blades and wind turbines with different power, as long as the outer diameter of the blade root bolts is the same, the same bolt extension fixture can be used, thus having strong versatility.

[0024] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the combination of blade root bolts, wind turbine blades, pitch bearings, and hub.

[0026] Figure 2 This is a perspective view of a bolt extension fixture for pre-tightening bolts on wind turbine blades according to the present invention.

[0027] Figure 3 yes Figure 2 The bolt extension fixture shown is viewed from direction A.

[0028] Figure 4 yes Figure 2 The bolt extension fixture shown is viewed from direction B.

[0029] Figure 5 yes Figure 3 A schematic diagram of the AA cross section.

[0030] Figure 6 This is a perspective view of the tooling body in this invention.

[0031] Figure 7 yes Figure 6 The tooling body shown is viewed from direction D.

[0032] Figure 8 yes Figure 6 The tooling body shown is viewed from direction E.

[0033] Figure 9 yes Figure 7 A schematic diagram of the FF cross-section.

[0034] Figure 10 This is a 3D view of the boss of the bolt extension fixture.

[0035] Figure 11 This is a side view of the boss in this invention.

[0036] Figure 12 yes Figure 11 The boss shown is viewed from the G direction or the H direction.

[0037] Figure 13 This is a schematic diagram of the bolt extension fixture and the blade root bolt assembly.

[0038] Figures 14 to 15 These are all three-dimensional structural schematic diagrams of the bolt extension tooling separator in this invention.

[0039] Figure 16 yes Figure 14 The bolt extension tooling separator shown is viewed from direction I.

[0040] Figure 17 yes Figure 16 A schematic diagram of the JJ cross-section.

[0041] Figure 18 yes Figure 14 The bolt extension tooling separator shown is viewed from direction K.

[0042] Figure 19 This is a schematic diagram of the assembly steps of the wind turbine blade, pitch bearing and hub in this invention.

[0043] Figure 20 This is a diagram showing the positional relationship between the washer and the hexagonal nut when tightened to the inner ring of the pitch bearing.

[0044] Figure 21 This is an assembly diagram of the main components of the hydraulic tensioner, along with the blade root bolts and bolt extension fixtures.

[0045] Figure 22 This is a schematic diagram of the separation process when the bolt extension tooling and the leaf root bolt are separated using a bolt extension tooling separator according to the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments.

[0047] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] This embodiment discloses a bolt extension fixture for preload of wind turbine blade bolts, in such a way as... Figure 1 The wind turbine blade 1 shown, after being assembled with the pitch bearing 2 and hub 3, is used to apply preload to the blade root bolt 11. Figures 2 to 5 As shown, the bolt extension fixture 4 includes a fixture body 41 and a boss 42. One end of the fixture body 41 is provided with an edge protrusion 43, which extends circumferentially along the end of the fixture body. The other end of the fixture body 41 is provided with a fixture edge chamfer 44, and the surface of the fixture body 41 is provided with an external surface thread 45. Specifically, as shown... Figures 6 to 9 As shown, the tooling body 41 is a cylindrical metal block. The edge of the outer cylindrical end face 411 of the tooling body 41 is the tooling edge chamfer 44. The edge of the inner cylindrical end face 412 of the tooling body 41 and the edge protrusion 43 are integrally machined. The center of the inner cylindrical end face 412 of the tooling body 41 is connected to the boss 42. The outer cylindrical end face is the end face of the tooling body away from the blade root bolt, and the inner cylindrical end face is the end face of the tooling body that mates with the blade root bolt.

[0049] 42-faceted boss Figures 10 to 12 As shown, it is a hexahedral magnet. The center of the hexahedral end face 421 of the boss 42 coincides with the center of the inner cylindrical end face 412 of the tooling body 41, that is, the inner cylindrical end face and the boss are coaxially connected, and the hexahedral end face 421 of the boss and the inner cylindrical end face 412 of the tooling body 41 are firmly welded together.

[0050] The cross-sectional diameter of the bolt extension fixture 4 is the same as the diameter of the bolt end face 111 of the leaf root bolt 11, and can be φ36mm, φ39mm, or φ45mm, etc. The hexagonal cross-section of the boss 42 of the bolt extension fixture 4 is the same as the cross-sectional shape of the inner hexagon 112 on the bolt end face 111 of the leaf root bolt 11. The axial length of the boss 42 of the bolt extension fixture 4 is less than or equal to the axial length (axial depth) of the inner hexagon 112 on the bolt end face 111. After the boss 42 enters the inner hexagon 112, the two can form a radial anti-rotation function. The edge protrusion 43 of the bolt extension fixture 4 can cooperate with the edge chamfer 113 provided on the bolt end face 111 of the leaf root bolt 11, ensuring that the outer surface of the leaf root bolt and the outer surface of the bolt extension fixture are on the same cylindrical surface, without any steps or recesses. The assembly of the bolt extension fixture 4 and the leaf root bolt 11 is as follows: Figure 13 As shown, when the bolt extension fixture 4 is engaged with the leaf root bolt 11, the boss 42 enters the internal hexagon 112. Under the action of magnetic force, the bolt extension fixture 4 and the leaf root bolt 11 are tightly integrated into one piece, and the outer surface thread 45 is continuous with the outer thread of the leaf root bolt.

[0051] This embodiment also proposes a bolt extension tooling separator 7, such as Figures 14 to 18 As shown, this is used to pull the bolt extension tool 4 from the leaf root bolt 11. The bolt extension tool separator 7 mainly consists of a separator body 71, an internal thread 72, and a separator root end pull ring 73. The separator body 71 is a hollow cylindrical metal, with one end face closed (called the closed end 711) and the other end face open (called the open end 712). The inner diameter of the separator body 71 is the same as the outer diameter of the bolt extension tool 4. The inner surface of the separator body 71 is provided with the internal thread 72, which can match the outer surface thread 45 of the bolt extension tool 4, so that the bolt extension tool 4 can be separated from the leaf root bolt 11 when the bolt extension tool separator 7 is pulled backward. The closed end 711 of the separator body 71 is externally connected to the pull ring 73. The pull ring can be rotatably set on the closed end 711 or directly welded to the closed end 711. The pull ring 73 is a hollow metal ring.

[0052] In this embodiment, the boss is a hexahedral magnet with a hexagonal radial cross-section, meaning the boss itself is a hexagonal prism structure. Correspondingly, the recess on the bolt end face is an inner hexagonal that engages with the boss to prevent radial rotation. However, in other embodiments, the boss can also be other shapes, such as a square prism or an octagonal prism, and the corresponding recess on the bolt end face can be a matching inner square or inner octagonal structure. Therefore, this invention does not limit the structural form of the boss, as long as it satisfies the requirement that the boss and the recess can achieve radial anti-rotation function after interlocking.

[0053] Combination Figure 19 The method for using a bolt extension fixture for preload of wind turbine blade bolts, as described above, specifically includes the following steps:

[0054] Step 1: The outer ring bolt hole 211 of the outer ring 21 of the pitch bearing 2 is connected to the hub flange hole 311 of the flange 31 of the hub 3 by bolts; the wind turbine blade 1 is connected to the inner ring bolt hole 221 of the inner ring 22 of the pitch bearing 2 by blade root bolts 11; Figure 20 Washer 5 and hexagonal nut 6 are screwed sequentially from the bolt end face 111 of blade root bolt 11 to the inner ring 22 of pitch bearing 2; after hexagonal nut 6 is tightened, the bolt end face 111 of blade root bolt 11 extends about 10mm beyond the end face of hexagonal nut 6.

[0055] Step 2: Insert the boss 42 of the bolt extension fixture 4 into the hexagonal 112 of the leaf root bolt until the edge protrusion 43 of the bolt extension fixture 4 contacts and engages with the edge chamfer 113 of the bolt end face 111 of the leaf root bolt 11. This is considered as the bolt extension fixture 4 and the leaf root bolt 11 being properly engaged. At this time, the outer surface thread 45 of the bolt extension fixture 4 is continuous with the outer thread of the leaf root bolt.

[0056] Step 3: Apply preload to the blade root bolts using the hydraulic tensioner 8; combined with Figure 21 The hydraulic tensioner 8 is a standard device used to apply preload to the root bolts of wind turbine blades. It includes a support sleeve 81, a puller 82, and a lever 83. Through the process hole 321 on the web 32 of the hub 3, the support sleeve 81 of the hydraulic tensioner is first placed on the root bolt 11 and covers the hexagonal nut 6. The support sleeve is used to hold the hexagonal nut. Then, the puller 82 is rotated and placed on the bolt extension fixture 4 and the outside of the root bolt 11. The inner wall thread of the puller is threadedly connected to the outer surface thread 45 and the outer thread of the root bolt. Then, the hydraulic tensioner 8 is pressurized to lengthen the root bolt 11. The lever 83 is used to rotate the hexagonal nut 6 so that the hexagonal nut is tightly against the inner ring of the pitch bearing and is in a locked state. Finally, the pressure is released, the puller 82 is unscrewed, the puller 82 is separated from the bolt extension fixture 4 and the root bolt 11, the support sleeve 81 is removed, and the preload of one root bolt 11 is completed.

[0057] Step 4, as follows Figure 22 As shown, the bolt extension tooling 4 is pulled off the leaf root bolt 11 using the bolt extension tooling separator 7; the open end 712 of the bolt extension tooling separator 7 is screwed into the bolt extension tooling 4, and the bolt extension tooling 4 is separated from the leaf root bolt 11 by pulling the pull ring 73 of the bolt extension tooling separator 7 away from the leaf root bolt.

[0058] Step 5: Repeat steps 2, 3 and 4 above to install the bolt extension fixture 4 onto the other leaf root bolts 11 and apply preload.

[0059] The bolt extension fixture designed in this invention has a simple structure, low cost, and strong versatility. It can be used to apply preload to the blade root bolts of different types of wind turbines, which helps to reduce the overall design length of the blade root bolts, thereby reducing the material cost of the bolts, and is also beneficial to the optimized design of the hub web.

[0060] The above description is merely a preferred embodiment of the present invention, and all aspects not detailed herein are existing technologies. Any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A bolt elongation tool for bolt pre-tightening force of a wind turbine blade, characterized in that: The bolt extension tool includes a tool body and a boss, the tool body is a cylindrical metal block, an outer surface of the tool body is provided with an outer surface thread, one end of the tool body is provided with an inner cylindrical end face, the other end is provided with an outer cylindrical end face, the boss is coaxially fixedly connected to the inner cylindrical end face, the boss is used for radially stopping rotation with a recess hole formed on a bolt end face of a blade root bolt, the boss is made of magnet, and the diameter of the tool body is the same as the diameter of the bolt end face of the blade root bolt. One end of the tool body is provided with an edge protrusion, the other end is provided with a tool edge chamfer, the edge of the inner cylindrical end face is integrally processed with the edge protrusion, and the edge of the outer cylindrical end face is the tool edge chamfer; the edge protrusion is used for cooperating with an edge chamfer arranged on the bolt end face of the blade root bolt to ensure that the outer surface of the blade root bolt and the outer surface of the bolt extension tool are on the same cylindrical surface.

2. The bolt elongation tool for bolt pre-tightening force of a wind turbine blade according to claim 1, characterized in that: The axial length of the boss is less than or equal to the axial depth of the recess hole.

3. The bolt elongation tool for bolt pre-tightening force of a wind turbine blade according to claim 1, characterized in that: The boss is a hexagonal prism with a radial cross section, and correspondingly, the recess hole is an internal hexagon.

4. The bolt elongation tool for bolt pre-tightening force of a wind turbine blade according to claim 1, characterized in that: The boss is welded to the inner cylindrical end face of the tool body.

5. The bolt elongation tool for bolt pre-tightening force of a wind turbine blade according to claim 1, characterized in that: The bolt extension tool further includes a bolt extension tool separator for pulling the bolt extension tool out of the blade root bolt, the bolt extension tool separator includes a separator body, the separator body is in a hollow cylindrical structure, one end face is closed and is called a closed end, and the other end face is open and is called an open end; the inner diameter of the separator body is the same as the outer diameter of the tool body of the bolt extension tool, the inner surface of the separator body is provided with an inner thread matched with the outer surface thread on the tool body, and at least one pull ring is arranged on the closed end.

6. The bolt elongation tool for bolt pre-tightening force of a wind power blade according to claim 1, characterized in that: The diameter of the tool body of the bolt extension tool is the same as the diameter of the bolt end face of the blade root bolt, and is not limited to φ36mm, φ39mm or φ45mm.

7. A method of using a bolt elongation tool for bolt pre-tensioning force of a wind turbine blade, characterized in that, The use method is based on the bolt extension tool for bolt pre-tightening force of a wind power blade according to any one of claims 1-6, and includes the following steps: Step 1, the outer circle bolt hole of the outer ring of the pitch bearing is connected to the hub flange hole of the flange of the hub through a bolt; the wind power blade is connected to the inner circle bolt hole of the inner ring of the pitch bearing through a blade root bolt; a washer and a hexagonal nut are sequentially screwed to the inner ring of the pitch bearing from the bolt end face of the blade root bolt; after the hexagonal nut is tightened, the bolt end face exceeds the end face of the hexagonal nut; Step 2, the boss of the bolt extension tool is inserted into the internal hexagon of the blade root bolt until the edge protrusion of the bolt extension tool cooperates with the edge chamfer of the bolt end face of the blade root bolt; Step 3, a hydraulic stretcher is used to apply pre-tightening force to the blade root bolt, the hydraulic stretcher includes a support seat, a puller and a lever; The process of applying pre-tightening force to the blade root bolt by the hydraulic stretcher is as follows: through the process hole on the web of the hub, the support seat is first sleeved on the blade root bolt and covers the hexagonal nut, then the puller is rotatably sleeved on the bolt extension tool and the blade root bolt, and then the hydraulic stretcher is pressurized to lengthen the blade root bolt, the lever is used to rotate the hexagonal nut so that the hexagonal nut is tightly attached to the inner ring of the pitch bearing and is in a locked state; finally, the pressure is released, the puller and the bolt extension tool and the blade root bolt are separated, the support seat is taken out, and the pre-tightening force application of one blade root bolt is completed. Step 4, separate the bolt extension tool from the blade root bolt by bolt extension tool separator; Step 5, repeat steps 2, 3 and 4, i.e. install the bolt extension tool to other blade root bolts to apply pre-tightening force.

8. The method of using a bolt extension tool for bolt pre-load force of a wind turbine blade according to claim 7, wherein: In step 2, the edge protrusion is considered to cooperate with the edge chamfer of the bolt end face, which means that the bolt extension tool is combined with the blade root bolt in place, and at this time the external surface thread of the bolt extension tool is continuous with the external thread of the blade root bolt.

9. The method of using a bolt extension tool for bolt pre-load force of a wind turbine blade according to claim 7, wherein: In step 4, the open end of the bolt extension tool separator is screwed into the bolt extension tool, and the bolt extension tool is separated from the blade root bolt by pulling the pull ring on the bolt extension tool separator away from the blade root bolt.

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