Wind power blade root connecting structure and wind power blade

Abstract

The utility model discloses a kind of wind power blade root connecting structure and wind power blade, including blade root glass steel, variable pitch bearing, multiple T type punch connecting structure and reinforcing connecting structure, the blade root glass steel and variable pitch bearing are connected between by multiple T type punch connecting structure along the circumferentially uniform arrangement, the reinforcing connecting structure includes outer metal plate, inner metal plate and multiple metal plate connecting piece, the outer metal plate is set to the outer circumferential surface of blade root glass steel and variable pitch bearing, the inner metal plate is set to the inner circumferential surface of blade root glass steel, the outer metal plate, inner metal plate, blade root glass steel and variable pitch bearing are connected between by multiple metal plate connecting piece enhancement, and metal plate connecting piece and T type punch connecting structure are located in different radial surface and do not interfere with each other.The utility model can effectively reduce the delamination risk and delamination expansion speed of blade root area while improving the load-carrying capacity of blade root, improve the reliability of wind power blade root.

Description

Technical Field

[0001] This utility model relates to the technical field of large wind turbine blades, and in particular to a root connection structure for wind turbine blades and a wind turbine blade. Background Technology

[0002] Wind turbine blades are the core components of wind turbines for capturing wind energy. The blade root, as the key part connecting the blade and the bearing, is directly related to the operational safety and service life of the wind turbine.

[0003] With the development of the wind power industry, reducing the levelized cost of electricity (LCOE) has become one of the main research and development directions for new wind turbines. According to the blade element momentum theory, the power generation of a wind turbine is directly proportional to the square of the blade length. Therefore, increasing the blade length is an effective means to reduce the LCOE, leading to increasingly longer blades designed and manufactured by various turbine manufacturers. However, as the blade length increases, the composite load borne by the blade root will increase significantly due to the increase in local load and the cumulative distance, posing more challenges to the design and manufacturing of the blade root connection.

[0004] Drilled T-bolt connections are currently the primary method for connecting wind turbine blade roots. This method involves drilling a ring of radial and axial holes at the blade root, installing nuts in the radial holes, and then securing the blade, flange, and bearing by connecting one end of the bolt to the nut and the other end to the bearing. However, this connection method has the following limitations when facing high loads:

[0005] 1. Wind turbine blades are all manufactured using composite material injection molding. However, injection molding cannot design thicker blade roots. This means that the only way to increase the load-bearing capacity of the blade roots is to increase the number of T-bolt holes. More holes mean a larger pitch circle diameter, which undoubtedly leads to increased costs and decreased manufacturing efficiency.

[0006] 2. Due to the preload of the bolt and the unevenness of the contact surface with the fiberglass, the fiberglass at the blade root is prone to fatigue delamination. Moreover, as a weak point of the composite material itself, the delamination crack will continue to propagate during the operation of the blade, which will pose a risk to the safety of the blade root. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wind turbine blade root connection structure that can effectively reduce the risk of delamination and the speed of delamination expansion in the blade root area while improving the load-bearing capacity of the blade root, thereby improving the reliability of the wind turbine blade root.

[0008] Another objective of this invention is to provide a wind turbine blade.

[0009] The objective of this utility model can be achieved by adopting the following technical solutions:

[0010] A wind turbine blade root connection structure includes a fiberglass blade root, a pitch bearing, multiple T-shaped perforated connection structures, and a reinforcing connection structure. The fiberglass blade root and the pitch bearing are connected by multiple T-shaped perforated connection structures evenly arranged circumferentially. The reinforcing connection structure includes an outer metal plate, an inner metal plate, and multiple metal plate connectors. The outer metal plate is disposed on the outer circumferential surface of the fiberglass blade root and the pitch bearing, and the inner metal plate is disposed on the inner circumferential surface of the fiberglass blade root. The outer metal plate, the inner metal plate, the fiberglass blade root, and the pitch bearing are reinforcedly connected by multiple metal plate connectors, and the metal plate connectors and the T-shaped perforated connection structures are located on different radial planes and do not interfere with each other.

[0011] Furthermore, the T-shaped perforated connection structure includes a first axial screw hole, a second axial screw hole, a first radial screw hole, a cylindrical nut, and a blade root double-ended bolt. The first axial screw hole is located inside the fiberglass at the blade root, and the second axial screw hole is located inside the pitch bearing. The central axes of the first axial screw hole and the second axial screw hole are collinear. The first radial screw hole is located inside the fiberglass at the blade root and forms a T-shaped connection with the first axial screw hole and the second axial screw hole. The cylindrical nut is located inside the first radial screw hole. The blade root double-ended bolt is screwed into the second axial screw hole and the first axial screw hole in sequence and connected to the cylindrical nut.

[0012] Furthermore, the metal plate connector includes a radial single-headed bolt and a matching nut.

[0013] Furthermore, two rows of first radial through holes are evenly arranged circumferentially inside the fiberglass root of the blade, and two rows of second radial through holes are evenly arranged circumferentially inside the pitch bearing. The outer metal plate is provided with first through holes and second through holes corresponding to the first and second radial through holes, respectively. The inner metal plate is provided with third through holes corresponding to the first radial through holes. The central axes of the first radial through holes and the corresponding first and third through holes are collinear, and the central axes of the second radial through holes and the corresponding second through holes are collinear. A portion of the radial single-headed bolts of the metal plate connectors are screwed into the first through holes, the first radial through holes, and the third through holes with collinear central axes and fixed with matching nuts. The radial single-headed bolts of the other portion of the metal plate connectors are screwed into the second through holes and the second radial through holes with collinear central axes and fixed with matching nuts.

[0014] Furthermore, a gasket is provided between the nut and the inner metal plate and the inner circumferential surface of the pitch bearing, and the gasket is formed with a curved shape that matches the curvature of the inner metal plate or the inner circumferential surface of the pitch bearing.

[0015] Furthermore, the first radial through hole and the first radial screw hole of the T-shaped perforation connection structure are distributed at intervals along the chord direction of the blade.

[0016] Furthermore, the outer metal plate and the inner metal plate are generally ring-shaped, each comprising multiple circumferentially distributed blocks.

[0017] Another objective of this utility model can be achieved by adopting the following technical solution:

[0018] A wind turbine blade includes the aforementioned wind turbine blade root connection structure.

[0019] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0020] 1. Based on the T-type connection, this utility model adds inner and outer metal plates, which are connected to the blade root and pitch bearing by pre-tightening force. After the double-headed bolts of the blade root are tightened, the load will be partially transferred by the outer metal plate due to the rigidity of the metal plate and its position on the outer wall surface with high load, thereby enhancing the safety of the blade root connection.

[0021] 2. This utility model, by setting metal plates on both the inner and outer sides of the blade root and using radial metal plate connectors to fix the inner and outer metal plates together, can effectively reduce the probability of interlayer delamination of the blade root composite material and improve the safety of the blade root connection.

[0022] 3. The metal plate of this utility model has continuity in the chord direction. The metal plate can transmit load in the chord direction, which can equalize the hole position with larger load to the hole with lower load, and prevent uneven load distribution caused by uneven blade stiffness, thereby affecting the safety of the blade root.

[0023] 4. The reinforced connection structure of this utility model can be installed after the T-shaped perforated connection structure has been pre-tightened. The rigidity of the metal plate can effectively reduce the risk of opening caused by the loosening of the bolt pre-tightening force. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the blade root connection structure of this utility model.

[0025] Figure 2 This is a cross-sectional view of the blade root connection structure of this utility model.

[0026] Figure 3 for Figure 2 A magnified view of a portion of point A in the middle.

[0027] Figure 4 Explosion-proof of the blade root connection structure of this utility model Figure 1 .

[0028] Figure 5 Explosion-proof of the blade root connection structure of this utility model Figure 2 . Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0030] Example 1:

[0031] like Figures 1 to 5 As shown, this embodiment provides a wind turbine blade root connection structure, including a blade root fiberglass 1, a pitch bearing 2, multiple T-shaped perforated connection structures, and a reinforcing connection structure. The blade root fiberglass 1 and the pitch bearing 2 are connected by multiple T-shaped perforated connection structures evenly arranged circumferentially. The reinforcing connection structure includes an outer metal plate 3, an inner metal plate 4, and multiple metal plate connectors 5. The outer metal plate 3 is disposed on the outer circumferential surface of the blade root fiberglass 1 and the pitch bearing 2, and the inner metal plate 4 is disposed on the inner circumferential surface of the blade root fiberglass 1. The outer metal plate 3, the inner metal plate 4, the blade root fiberglass 1, and the pitch bearing 2 are reinforcedly connected by multiple metal plate connectors 5. The metal plate connectors 5 include radial single-headed bolts 501 and matching nuts 502, which can be hexagonal or octagonal nuts. The metal plate connectors 5 and the T-shaped perforated connection structures are located on different radial surfaces and do not interfere with each other.

[0032] Specifically, the T-shaped drilled connection structure includes a first axial screw hole 102, a second axial screw hole 202, a first radial screw hole 103, a cylindrical nut 6, and a blade root double-ended bolt 7. The first axial screw hole 102 is located inside the fiberglass 1 at the blade root, and the second axial screw hole 202 is located inside the pitch bearing 2. The central axes of the first axial screw hole 102 and the second axial screw hole 202 are collinear. The first radial screw hole 103 is located inside the fiberglass 1 at the blade root and is T-shaped through the first axial screw hole 102 and the second axial screw hole 202. The cylindrical nut 6 is located inside the first radial screw hole 103. The blade root double-ended bolt 7 is screwed into the second axial screw hole 202 and the first axial screw hole 102 in sequence and connected to the cylindrical nut 6. At the same time, a preload is applied to the blade root double-ended bolt 7.

[0033] Specifically, two rows of first radial through holes 101 are evenly arranged circumferentially inside the fiberglass 1 at the blade root, and two rows of second radial through holes 201 are evenly arranged circumferentially inside the pitch bearing 2. The number of first radial through holes 101 and second radial through holes 201 are the same and they correspond one-to-one. The central axes of the corresponding first radial through holes 101 and second radial through holes 201 are located on the same radial plane. The outer metal plate 3 is provided with first through holes 301 and second through holes 302 corresponding to the first radial through holes 101 and second radial through holes 201, respectively. The inner metal plate 4 is provided with a third through hole 401 corresponding to the first radial through hole 101. The central axes of a radial through hole 101 and the corresponding first through hole 301 and third through hole 401 are collinear. The central axes of a second radial through hole 201 and the corresponding second through hole 302 are collinear. A portion of the radial single-headed bolts 501 of the metal plate connector 5 are screwed into the first through hole 301, the first radial through hole 101 and the third through hole 401 with collinear central axes and fixed with matching nuts 502. The other portion of the radial single-headed bolts 501 of the metal plate connector 5 are screwed into the second through hole 302 and the second radial through hole 201 with collinear central axes and fixed with matching nuts 502. At the same time, a preload is applied to the radial single-headed bolts.

[0034] In this embodiment, a washer 503 is provided between the nut 502 and the inner metal plate 4 and the inner peripheral surface of the pitch bearing 2, respectively. The washer 503 is formed with a curved shape that matches the curvature of the inner metal plate 4 or the inner peripheral surface of the pitch bearing 2, so as to prevent the straight nut from not conforming to the blade surface with a certain curvature, and the nut from slipping or damaging the fiberglass during the preload loading process.

[0035] The first radial through hole 101 and the first radial screw hole 103 are distributed at intervals in the chordal direction of the blade, and at the same time, they need to be spaced a certain distance in the axial direction to ensure that each radial through hole does not affect the original T-shaped connection.

[0036] In this embodiment, due to the large pitch circle of the blade root, the inner and outer metal plates can be divided into multiple circumferentially distributed segments. This embodiment uses six segments as an example. Installing the inner and outer metal plates in six segments respectively can strengthen the blade root in both the axial and chordal directions, reduce the risk of loosening the blade root bolt preload, and improve the safety of the blade root connection. Due to high-altitude hoisting and the manufacturing tolerances of the fiberglass blade root, installation may be difficult. This example provides an feasible installation method, the core idea of ​​which is pre-installation on the blade root side. First, the three outer metal plates and their corresponding inner metal plates are pre-installed, and it is confirmed that the inner diameter of the outer metal plates is within the installation tolerance range. Simultaneously, the other three inner metal plates are temporarily bonded to the inner circumferential surface using adhesive. Then, the blade is lifted and connected using a T-shaped perforated connection structure in a normal blade installation manner. Finally, the other three outer metal plates with the pre-installed metal plate connectors are lifted, aligned with the radial through holes, and the nuts are tightened inside the blade to complete the installation.

[0037] If the blade root pitch circle is small, the inner and outer metal plates can be connected to the blade root and bearing on the ground before hoisting and installing the entire assembly onto the wind turbine blade. The inner and outer metal plates ensure a more uniform distribution of stiffness in the chord direction at the blade root, thereby further homogenizing the load.

[0038] Example 2:

[0039] This embodiment provides a wind turbine blade, including the wind turbine blade root connection structure described in Embodiment 1.

[0040] The above description is only a preferred embodiment of this utility model patent, but the protection scope of this utility model patent is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope disclosed in this utility model patent, based on the technical solution and utility model patent concept of this utility model patent, shall fall within the protection scope of this utility model patent.

Claims

1. A wind turbine blade root connection structure, characterised in that: The device includes a fiberglass blade root section, a pitch bearing, multiple T-shaped perforated connection structures, and a reinforcing connection structure. The fiberglass blade root section and the pitch bearing are connected by multiple T-shaped perforated connection structures evenly arranged circumferentially. The reinforcing connection structure includes an outer metal plate, an inner metal plate, and multiple metal plate connectors. The outer metal plate is disposed on the outer circumferential surface of the fiberglass blade root section and the pitch bearing, and the inner metal plate is disposed on the inner circumferential surface of the fiberglass blade root section. The outer metal plate, the inner metal plate, the fiberglass blade root section, and the pitch bearing are reinforcedly connected by multiple metal plate connectors, and the metal plate connectors and the T-shaped perforated connection structures are located on different radial planes and do not interfere with each other.

2. A wind turbine blade root connection structure according to claim 1, characterised in that: The T-shaped drilling connection structure includes a first axial screw hole, a second axial screw hole, a first radial screw hole, a cylindrical nut, and a blade root double-ended bolt. The first axial screw hole is located inside the fiberglass at the blade root, and the second axial screw hole is located inside the pitch bearing. The central axes of the first axial screw hole and the second axial screw hole are collinear. The first radial screw hole is located inside the fiberglass at the blade root and forms a T-shaped connection with the first axial screw hole and the second axial screw hole. The cylindrical nut is located inside the first radial screw hole. The blade root double-ended bolt is screwed into the second axial screw hole and the first axial screw hole in sequence and connected to the cylindrical nut.

3. A wind turbine blade root connection structure according to claim 1, characterised in that: The metal plate connector includes a radial single-ended bolt and a matching nut.

4. A wind turbine blade root connection structure according to claim 1, characterised in that: Two rows of first radial through holes are evenly arranged circumferentially inside the fiberglass root of the blade. Two rows of second radial through holes are evenly arranged circumferentially inside the pitch bearing. The outer metal plate is provided with first through holes and second through holes corresponding to the first and second radial through holes. The inner metal plate is provided with third through holes corresponding to the first radial through holes. The central axes of the first radial through holes and the corresponding first and third through holes are collinear. The central axes of the second radial through holes and the corresponding second through holes are collinear. A portion of the radial single-headed bolts of the metal plate connectors are screwed into the first through holes, the first radial through holes, and the third through holes with collinear central axes and fixed with matching nuts. The radial single-headed bolts of the other portion of the metal plate connectors are screwed into the second through holes and the second radial through holes with collinear central axes and fixed with matching nuts.

5. A wind turbine blade root connection structure according to claim 4, characterised in that: A gasket is provided between the nut and the inner metal plate and the inner circumferential surface of the pitch bearing, and the gasket is formed with a curved shape that matches the curvature of the inner metal plate or the inner circumferential surface of the pitch bearing.

6. A wind turbine blade root connection structure according to claim 4, characterised in that: The first radial through hole and the first radial screw hole of the T-shaped perforation connection structure are distributed at intervals along the chord direction of the blade.

7. A wind turbine blade root connection structure according to claim 1, characterised in that: The outer metal plate and the inner metal plate are in a ring shape, each comprising multiple circumferentially distributed blocks.

8. A wind turbine blade, characterised in that Includes the wind turbine blade root connection structure as described in any one of claims 1 to 7.

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