Fan blade and wind turbine generator

Abstract

The utility model discloses a fan blade and a wind turbine generator, and relates to the technical field of fan blades, and the fan blade comprises a sectional blade body and a plurality of studs. The sectional type blade body comprises a blade root part and a blade tip part, the blade root part is provided with a first connecting section, a plurality of first threaded holes are formed in the first connecting section, the blade tip part is provided with a second connecting section, a plurality of second threaded holes are formed in the second connecting section, and the first threaded holes and the corresponding second threaded holes are opposite in rotating direction. And the two ends of each double-end stud are screwed with the corresponding first threaded hole and the corresponding second threaded hole respectively so as to connect the blade root part and the blade tip part. When a fan galloping phenomenon occurs on the fan blade, the blade can be actively disconnected, the aerodynamic load of the blade is unloaded, and the bearing capacity of a hub is reduced, so that the centrifugal force of a wind wheel is reduced, the rotating speed of the impeller is gradually reduced to stop, and the purpose of preventing the fan galloping accident is achieved.

Description

Technical Field

[0001] This application relates to the technical field of fan blades, and particularly relates to a fan blade and a wind turbine generator set. Background Art

[0002] Fan runaway is a phenomenon in which the braking system of a wind turbine generator set fails, the rotational speed of the wind wheel exceeds the rated speed, and the wind turbine generator set is in an out-of-control state. Fan runaway can lead to accidents such as blade damage and tower collapse, causing serious economic losses and even endangering lives. Therefore, when fan runaway occurs, measures should be taken in a timely manner to prevent fan runaway accidents to avoid incalculable losses.

[0003] Currently, the measures for dealing with fan runaway are limited to brake control means and pitch control means. These measures start from the causes of fan runaway, are difficult to implement, lack safety, and cannot effectively control fan runaway. Moreover, these measures require the wind turbine generator set to be in an energized state, and the wind turbine generator set is still in an un-energized state from just after hoisting to before grid connection. The pitch system and the brake system cannot be started, and this period is a high-incidence period of fan runaway. At this time, the above-mentioned measures for preventing fan runaway are difficult to implement.

[0004] Therefore, how to prevent fan runaway accidents from occurring when both the pitch system and the brake system cannot work is a technical problem that needs to be solved by those skilled in the art at present. Summary of the Utility Model

[0005] The purpose of this application is to provide a fan blade and a wind turbine generator set that can prevent fan runaway accidents from occurring when both the pitch system and the brake system cannot work.

[0006] To achieve the above purpose, this application provides a fan blade, including:

[0007] A segmented blade body, the segmented blade body includes a blade root and a blade tip. The blade root is provided with a first connection section, and a plurality of first threaded holes are provided on the first connection section. The blade tip is provided with a second connection section, and a plurality of second threaded holes are provided on the second connection section. The rotation directions of the first threaded holes and the corresponding second threaded holes are opposite;

[0008] A plurality of stud bolts, and both ends of the stud bolts are respectively screwed tightly with the first threaded holes and the corresponding second threaded holes to connect the blade root and the blade tip.

[0009] In some embodiments, the fan blade further includes an adhesive layer, which is connected between the first connection section and the second connection section. The adhesive layer is used to fill the gap between the first connection section and the second connection section and to improve the connection strength between the first connection section and the second connection section.

[0010] In some embodiments, the stud has a torsion portion in the middle. The torsion portion is used for a torsion wrench to clamp to apply the torque required for screwing the stud, and the dimension of the torsion portion along the axis of the stud is equal to the thickness of the adhesive layer.

[0011] In some embodiments, the torsion portion is specifically an anti-slip contact surface provided on the outer surface of the stud, and anti-slip lines are provided on the anti-slip contact surface.

[0012] In some embodiments, the fan blade further includes a strengthening structure, which covers the connection between the blade root and the blade tip in the circumferential direction to improve the connection strength between the blade root and the blade tip.

[0013] In some embodiments, the strengthening structure includes at least two layers of biaxial fabric layers, and the width of any layer of the biaxial fabric layer is greater than the thickness of the adhesive layer.

[0014] In some embodiments, the first connection section includes a first windward section and a first leeward section. The number of the first threaded holes on the first windward section is the same as that of the first threaded holes on the first leeward section, and both are at least two.

[0015] The second connection section includes a second windward section and a second leeward section. The number of the second threaded holes on the second windward section is the same as that of the second threaded holes on the second leeward section, and both are at least two.

[0016] In some embodiments, one first threaded hole is provided at each of the first leading edge and the first trailing edge of the first connection section, and one second threaded hole is provided at each of the second leading edge and the second trailing edge of the second connection section.

[0017] In some embodiments, a weak fracture position is provided on the stud, and the weak fracture position is used to adjust the ultimate allowable load of the stud.

[0018] This application also provides a wind turbine, including the fan blade described in any one of the above.

[0019] Compared with the above background art, the fan blade provided by the embodiment of the present application includes a segmented blade body and a plurality of stud bolts. Among them, the segmented blade body includes a blade root part and a blade tip part. The blade root part is provided with a first connection section, and a plurality of first threaded holes are provided on the first connection section. The blade tip part is provided with a second connection section, and a plurality of second threaded holes are provided on the second connection section. The rotation directions of the first threaded holes and the corresponding second threaded holes are opposite. The two ends of the stud bolt are respectively screwed with the first threaded hole and the corresponding second threaded hole to connect the blade root part and the blade tip part.

[0020] It can be seen that the above fan blade adopts a segmented blade structure. Specifically, the blade can be separated into a blade root part and a blade tip part at a certain position of the blade. A plurality of first threaded holes are provided on the first connection section of the blade root part, and a plurality of second threaded holes are provided on the second connection section of the blade tip part. After the blade is manufactured in two sections and transported to the wind farm, a plurality of stud bolts are used to connect the blade root part and the blade tip part respectively, thereby forming the overall structure of the fan blade.

[0021] The beneficial effects of the fan blade arranged in this way mainly include: adopting a segmented blade body structure, and at the same time using stud bolts to connect the blade root part and the blade tip part of the segmented blade body. The vector sum of the ultimate stresses of each stud bolt should be critical to the centrifugal stress provided by the wind wheel speed at the blade disconnection section when the fan runs away. In this way, when the wind wheel speed of the fan is too high during a runaway, the segmented surface of the blade can be disconnected simultaneously, achieving the purpose of preventing the fan from running away and toppling the tower. That is to say, by adopting such a setting method, when a fan runaway phenomenon occurs, the blade can actively disconnect, unload the aerodynamic load of the blade, reduce the bearing capacity of the hub, thereby reducing the centrifugal force of the wind wheel, and gradually reducing the impeller speed to a stop, so as to achieve the purpose of preventing the occurrence of fan runaway accidents. In this way, measures can be taken from the perspective of the blade to prevent the occurrence of fan runaway accidents, so as to achieve the purpose of preventing fan runaway accidents when both the pitch system and the braking system cannot work. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the related art. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0023] Figure 1 It is a sectional view of the first fan blade in the embodiment of the present application;

[0024] Figure 2 It is a connection diagram of the first fan blade in the embodiment of the present application;

[0025] Figure 3 is Figure 2 Schematic diagram of the root structure of the middle blade

[0026] Figure 4 is Figure 2 Schematic diagram of the tip structure of the middle blade

[0027] Figure 5 is Figure 2 Schematic diagram of the connection between the root of the middle blade and the stud

[0028] Figure 6 Schematic diagram of the segmentation of the second type of wind turbine blade in the embodiment of the present application

[0029] Figure 7 Schematic diagram of the connection of the second type of wind turbine blade in the embodiment of the present application

[0030] Figure 8 Schematic diagram of the segmentation of the third type of wind turbine blade in the embodiment of the present application

[0031] Figure 9 Schematic diagram of the connection of the third type of wind turbine blade in the embodiment of the present application

[0032] Wherein:

[0033] 10 - Segmented blade body

[0034] 11 - Blade root, 111 - First connection section, 1111 - First windward section, 1112 - First leeward section, 1113 - First leading edge, 1114 - First trailing edge, 112 - First threaded hole

[0035] 12 - Blade tip, 121 - Second connection section, 1211 - Second windward section, 1212 - Second leeward section, 1213 - Second leading edge, 1214 - Second trailing edge, 122 - Second threaded hole

[0036] 20 - Stud Specific implementation mode

[0037] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0038] In order to enable those skilled in the art of this technology to better understand the solution of the present application, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation modes.

[0039] It should be noted that the orientation terms such as "upper end, lower end, left side, right side" described below are defined based on the accompanying drawings of the specification.

[0040] Please refer to Figures 1 to 9 , Figure 1 which is a sectional view of the first type of wind turbine blade in the embodiment of the present application; Figure 2 which is a connection view of the first type of wind turbine blade in the embodiment of the present application; Figure 3 is Figure 2 a schematic view of the root structure of the middle part; Figure 4 is Figure 2 a schematic view of the tip structure of the middle part; Figure 5 is Figure 2 a connection view of the root of the middle part and the stud; Figure 6 which is a sectional view of the second type of wind turbine blade in the embodiment of the present application; Figure 7 which is a connection view of the second type of wind turbine blade in the embodiment of the present application; Figure 8 which is a sectional view of the third type of wind turbine blade in the embodiment of the present application; Figure 9 which is a connection view of the third type of wind turbine blade in the embodiment of the present application.

[0041] The wind turbine blade provided by the embodiment of the present application includes a segmented blade body 10 and a plurality of studs 20.

[0042] The segmented blade body 10 includes a root part 11 and a tip part 12. The root part 11 is provided with a first connection section 111, and a plurality of first threaded holes 112 are provided on the first connection section 111. The tip part 12 is provided with a second connection section 121, and a plurality of second threaded holes 122 are provided on the second connection section 121. The rotation directions of the first threaded hole 112 and the corresponding second threaded hole 122 are opposite.

[0043] Both ends of the stud 20 are screwed tightly with the first threaded hole 112 and the corresponding second threaded hole 122 respectively to connect the root part 11 and the tip part 12. Specifically, both ends of the stud 20 are provided with a first external thread and a second external thread respectively. Among them, the first external thread is adapted to the first threaded hole 112, and the second external thread is adapted to the second threaded hole 122. Since the rotation directions of the first threaded hole 112 and the corresponding second threaded hole 122 are opposite, therefore, through the thread fit between the first external thread and the first threaded hole 112, and the thread fit between the second external thread and the second threaded hole 122, both ends of the stud 20 are screwed tightly with the first threaded hole 112 and the corresponding second threaded hole 122 respectively, so as to achieve the purpose of connecting the root part 11 and the tip part 12.

[0044] It can be seen that the above-mentioned wind turbine blade adopts a segmented blade structure. Specifically, the blade can be separated into a blade root 11 and a blade tip 12 at a certain position of the blade. A number of first threaded holes 112 are provided on the first connection section 111 of the blade root 11, and a number of second threaded holes 122 are provided on the second connection section 121 of the blade tip 12. After the blade is manufactured in two sections and transported to the wind farm, a number of stud bolts 20 are used to connect the blade root 11 and the blade tip 12 respectively, thereby forming the overall structure of the wind turbine blade.

[0045] Considering that the current means that can be taken for the wind turbine overspeed phenomenon are limited to two methods: braking control means and pitch control means. These measures start from the causes of the wind turbine overspeed and require the wind power generating unit to be in the powered-on state. Since the pitch system and the braking system cannot be started when the wind power generating unit is in the unpowered state, and this period is a high-incidence period of the wind turbine overspeed phenomenon, it is necessary to take measures from the perspective of the wind turbine blades to prevent the occurrence of wind turbine overspeed accidents.

[0046] To this end, the present application adopts a segmented blade body 10 structure, and at the same time uses stud bolts 20 to connect the blade root 11 and the blade tip 12 of the segmented blade body 10. The vector sum of the ultimate stresses of each stud bolt 20 should be critical to the centrifugal stress provided by the wind turbine rotor speed at the blade disconnection section when the wind turbine overspeed. In this way, when the wind turbine rotor speed is too high during overspeed, the segmented surface of the blade can be disconnected simultaneously, achieving the purpose of preventing the wind turbine from overspeed and tower collapse.

[0047] Adopting such a setting method, when the wind turbine overspeed phenomenon occurs, the blade can actively disconnect, unload the aerodynamic load of the blade, reduce the bearing capacity of the hub, thereby reducing the centrifugal force of the wind turbine rotor, and gradually reducing the impeller speed to stop, so as to achieve the purpose of preventing the occurrence of wind turbine overspeed accidents. In this way, measures can be taken from the perspective of the blade to prevent the occurrence of wind turbine overspeed accidents, thereby realizing the prevention of wind turbine overspeed accidents when both the pitch system and the braking system cannot work.

[0048] The wind turbine blade of the present application adopts a segmented design. The segmented section of the blade depends on the length, shape of the blade and the blade section that can generate the maximum stress according to the aerodynamic load during blade design, and is flexibly designed. Moreover, the specification parameters and the number of the stud bolts 20 should be determined according to the ultimate stress of the disconnection section of the blade body. The following is a specific description:

[0049] As Figure 3 shown, according to the combined internal force relationship of the blade section flapping moment Sx, the waving moment Sy and the axial force Fz, by integrating along the area of the entire section of the blade that bears normal stress, the axial force in the Z direction of any section of the blade can be deduced as:

[0050]

[0051] Wherein, X and Y are the coordinates of each point on the blade cross-section, A is the blade cross-sectional area, and S X is the flapping moment of the blade cross-section, and S Y is the pitching moment of the blade cross-section. σ is the normal stress at any point on the blade cross-section, E is the elastic modulus of the blade cross-section, and ε0, ρ are undetermined coefficients, which can be determined according to the static equilibrium conditions on the cross-section.

[0052] The maximum limit axial force of the stud 20 at this cross-section is:

[0053]

[0054] Wherein, the above Fz is the axial force received by the blade at this cross-section, analyzing the force received by the blade, and Fz 螺栓 is the resultant axial force in the Z direction received by all the studs 20 at the cross-section during the operation of the wind turbine blade, and Fz 极限 is the ultimate allowable load of a single stud 20, which is an inherent property of a single stud 20. N is the number of studs 20 at this cross-section of the blade, and N = Fz 螺栓 / Fz 极限 .

[0055] When the blade is operating normally, the rotational speed is the rated rotational speed. The relationship between the axial force of the blade cross-section and the resultant axial force of the stud 20 at this cross-section is:

[0056]

[0057] That is, N is greater than or equal to Fz / Fz 极限 .

[0058] According to the above formula, the position of the blade cross-section, the number and specifications of the studs 20 on the blade cross-section can be determined according to the load during the design process, so as to achieve the purpose of the blade operating normally and safely.

[0059] When the blade runs away, the rotational speed exceeds the rated rotational speed. The relationship between the axial force of the blade cross-section and the resultant axial force of the stud 20 at this cross-section is:

[0060]

[0061] At this time, all the studs 20 on the blade cross-section are broken, and the blade unloads by reducing its own weight to achieve the purpose of preventing the blade from running away.

[0062] In some embodiments, the wind turbine blade further includes an adhesive layer, which is connected between the first connection cross-section 111 and the second connection cross-section 121. The adhesive layer is used to fill the gap between the first connection cross-section 111 and the second connection cross-section 121, and is used to improve the connection strength between the first connection cross-section 111 and the second connection cross-section 121.

[0063] Specifically, structural adhesive is fully applied on the first connection section 111 of the blade root 11 and the second connection section 121 of the blade tip 12. The blade root 11 and the blade tip 12 are connected by the stud 20, so that the structural adhesive between the first connection section 111 and the second connection section 121 forms an adhesive layer after curing. This adhesive layer can not only fill the gap between the first connection section 111 and the second connection section 121 to achieve a sealing effect, but also improve the connection strength between the first connection section 111 and the second connection section 121, ensuring the structural stability of the blade under normal working conditions.

[0064] In some embodiments, the stud 20 is provided with a torsion part in the middle. The torsion part is used for clamping by a torsion wrench. The torsion wrench clamps the torsion part of the stud 20 to apply the torque required for screwing the stud 20. The dimension of the torsion part along the axis direction of the stud 20 is equal to the thickness of the adhesive layer.

[0065] In this embodiment, the torsion part is specifically an anti-slip contact surface provided on the outer surface of the stud 20. The outer diameter of the anti-slip contact surface can be larger than the outer diameter of other parts of the stud 20. Further, anti-slip lines are provided on the anti-slip contact surface, and the anti-slip lines can increase the friction with the torsion wrench, ensuring that the torsion wrench applies a stable torque to the stud 20.

[0066] In some embodiments, the wind turbine blade further includes a strengthening structure. The strengthening structure covers the connection part of the blade root 11 and the blade tip 12 along the circumferential direction to improve the connection strength between the blade root 11 and the blade tip 12.

[0067] In this embodiment, the strengthening structure includes at least two layers of biaxial fabric layers, and the width of any layer of biaxial fabric layer is greater than the thickness of the adhesive layer.

[0068] For example, two layers of biaxial fabric layers can be used for reinforcement on the outer side of the connection part of the blade segments. With this setting, it can not only achieve the purpose of preventing the wind turbine from running away, but also ensure the structural strength of the blades for the normal operation of the in-service wind power generation unit.

[0069] In some embodiments, the first connection section 111 includes a first windward section 1111 and a first leeward section 1112. The number of the first threaded holes 112 on the first windward section 1111 is the same as that on the first leeward section 1112, and both are at least two; similarly, the second connection section 121 includes a second windward section 1211 and a second leeward section 1212. The number of the second threaded holes 122 on the second windward section 1211 is the same as that on the second leeward section 1212, and both are at least two.

[0070] In some embodiments, a first threaded hole 112 is provided at both the first leading edge 1113 and the first trailing edge 1114 of the first connection section 111, and a second threaded hole 122 is provided at both the second leading edge 1213 and the second trailing edge 1214 of the second connection section 121.

[0071] Of course, according to actual needs, three first threaded holes 112 can be provided on both the first windward section 1111 and the first leeward section 1112 of the first connection section 111, and three second threaded holes 122 can be provided on both the second windward section 1211 and the second leeward section 1212 of the second connection section 121.

[0072] It should be noted that the specification parameters and the number of the stud bolts 20 should be determined according to the ultimate stress of the blade break section. The vector sum of the ultimate stresses of the stud bolts 20 should be critical to the centrifugal stress provided by the wind wheel speed at the blade break section when the wind turbine runs away. When the wind wheel speed is too high during the runaway of the wind turbine, the stud bolts 20 at the blade segmentation surface can be disconnected simultaneously to achieve the purpose of preventing the wind turbine from running away.

[0073] In some embodiments, a weak fracture position is provided on the stud bolt 20, and the weak fracture position is used to adjust the ultimate allowable load of the stud bolt 20.

[0074] By setting the weak fracture position, the ultimate allowable load of each stud bolt 20 can be limited within a preset range, so as to ensure that the stud bolts 20 at the blade segmentation surface can be disconnected simultaneously when the wind wheel speed is too high during the runaway of the wind turbine.

[0075] Compared with traditional measures, the wind turbine blade adopted in this application can effectively prevent the wind turbine from running away in the case of the pitch system out of control and the braking system out of control, and reduce the accident rate of the wind turbine running away; at the same time, using the stud bolts 20 to connect the root 11 and the tip 12 of the segmented blade body 10 can not only make the blade segmentation surface break automatically simultaneously when the wind wheel speed is too high according to the bolt strength, but also has high social and economic benefits.

[0076] In addition, although the blade structure is changed compared with the traditional blade, it does not affect the flapping, pitching and torsional stiffness of the blade:

[0077] Table 1 shows the sectional stiffness of the traditional blade design and the blade design of this scheme at 10 meters, 20 meters and 30 meters away from the blade root (except for the cut at the maximum chord length added additionally in the two designs, the rest of the plies are kept consistent).

[0078] Table 1

[0079]

[0080] From the stiffness comparison of the three sections in Table 1, it can be seen that the new blade proposed in this application has the same stiffness as the traditional structure blade in terms of swing, flapping and torsional stiffness, thereby achieving the purpose of preventing wind turbine runaway accidents while ensuring the overall structural strength and output performance of the blade.

[0081] In summary, the role of active fracture of the blades when the rotor speed is too high is to enable the three blades to be disconnected separately when the wind turbine runaway phenomenon occurs. The position of the segmented section can be flexibly designed according to the length and shape of the blades and the aerodynamic load of the blades when the wind turbine is running, which can generate the maximum stress on the position of the blade section. When the blade pitch angle is uncontrollable, the blades can achieve the purpose of active disconnection; at the same time, the blade connection method is a double-headed stud 20 connection. The specification parameters and number of the double-headed studs 20 can be flexibly designed according to the maximum stress at the blade disconnection section during the operation of the wind turbine (the maximum stress is related to the swing bending moment and the flapping bending moment at the blade section, and the bending moment at the blade section is related to the centrifugal force during the operation of the blade, the tangential force and axial force caused by the airflow pressure and the aerodynamic force acting on the blade) as the ultimate stress of the stud.

[0082] In addition, the present application uses structural adhesive to reinforce and fill the gaps at the blade section, and adds two layers of biaxial cloth to the outer surface of the blade for structural reinforcement to ensure that the blade meets the strength requirements during the operation of the wind turbine generator set, and ensures that the blade designed by the present invention can operate safely in service.

[0083] The present application provides a wind turbine generator set, including the wind turbine blades described in the above specific embodiments; other parts of the wind turbine generator set can refer to relevant technologies and will not be elaborated in this article.

[0084] It should be noted that, in this specification, relational terms such as first and second are merely used to distinguish one entity from other entities, but do not necessarily require or imply any actual relationship or order between these entities.

[0085] The above is a detailed introduction to the wind turbine blades and wind turbine generator system provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the solution and core ideas of the present application. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the present application.

Claims

1. A wind turbine blade, characterized in that, Comprising: A segmented blade body, the segmented blade body includes a blade root and a blade tip, the blade root is provided with a first connection section, a plurality of first threaded holes are provided on the first connection section, the blade tip is provided with a second connection section, a plurality of second threaded holes are provided on the second connection section, and the rotation directions of the first threaded hole and the corresponding second threaded hole are opposite; A plurality of stud bolts, both ends of the stud bolt are respectively screwed with the first threaded hole and the corresponding second threaded hole to connect the blade root and the blade tip.

2. The fan blade according to claim 1, wherein The fan blade further includes an adhesive layer, the adhesive layer is connected between the first connection section and the second connection section, the adhesive layer is used to fill the gap between the first connection section and the second connection section, and is used to improve the connection strength between the first connection section and the second connection section.

3. The fan blade according to claim 2, wherein, The stud bolt is provided with a twisting portion in the middle, the twisting portion is used for a twisting wrench to clamp to apply the torque required for the stud bolt to be screwed, and the dimension of the twisting portion along the axis direction of the stud bolt is equal to the thickness of the adhesive layer.

4. The fan blade according to claim 3, characterized in that, The twisting portion is specifically an anti-slip contact surface provided on the outer surface of the stud bolt, and anti-slip patterns are provided on the anti-slip contact surface.

5. The fan blade according to claim 2, wherein, The fan blade further includes a strengthening structure, the strengthening structure covers the connection part of the blade root and the blade tip along the circumferential direction to improve the connection strength between the blade root and the blade tip.

6. The fan blade according to claim 5, characterized in that, The strengthening structure includes at least two layers of biaxial fabric layers, and the width of any layer of the biaxial fabric layer is greater than the thickness of the adhesive layer.

7. The fan blade according to any one of claims 1-6, characterized in that, The first connection section includes a first windward section and a first leeward section, the number of the first threaded holes on the first windward section is the same as the number of the first threaded holes on the first leeward section, and both are at least two; The second connection section includes a second windward section and a second leeward section, the number of the second threaded holes on the second windward section is the same as the number of the second threaded holes on the second leeward section, and both are at least two.

8. The fan blade according to any one of claims 1-6, characterized in that, One first threaded hole is provided at both the first leading edge and the first trailing edge of the first connection section, and one second threaded hole is provided at both the second leading edge and the second trailing edge of the second connection section.

9. The fan blade according to any one of claims 1-6, characterized in that, A weak fracture position is provided on the stud bolt, and the weak fracture position is used to adjust the ultimate allowable load of the stud bolt.

10. A wind turbine unit, characterized in that, Including the fan blade according to any one of claims 1-9.

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