A connection structure between a wind turbine blade and a variable pitch bearing and an application method thereof

Abstract

A connection structure between a wind turbine blade and a variable pitch bearing, wherein the right end of a double-headed screw is threadedly connected to an embedded bolt sleeve, and the left end of the double-headed screw passes through a low round sleeve and a high round sleeve in turn to the left and is threadedly connected to a nut, and the right end of the high round sleeve and the left end of the low round sleeve are spherically fitted together, so that the double-headed screw will not be subjected to bending force, thereby facilitating the service life of the double-headed screw. The steps of connecting the wind turbine blade and the variable pitch bearing together using the connection structure are as follows: 1. Using the embedded bolt sleeve at the trailing edge of the wind turbine blade as a reference, screw a positioning pin into each of three embedded bolt sleeves with an angle of 120°; 2. Screw the double-headed screw into the remaining embedded bolt sleeves of the wind turbine blade; 3. Move the wind turbine blade until the flange fits the variable pitch bearing; 4. Install the automatic bolt centering device, and then screw on the nut; 5. Replace the positioning pin with a double-headed screw, install the automatic bolt centering device on it, and then screw on the nut.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator installation, and in particular to a connection structure between a wind turbine blade and a variable pitch bearing, and a method and steps for connecting the wind turbine blade and the variable pitch bearing using the connection structure. Background Art

[0002] As a precision equipment, wind turbines operate in the field under poor natural conditions for a long time. To ensure the long-term effective operation of the wind turbine, it is necessary to pay attention to every detail of the wind turbine and carefully care for every component. The appearance of the wind turbine is mainly composed of four parts: tower, nacelle, wheel load, and blades. And these four parts need to be connected by bolts. Therefore, during the installation of the wind turbine, the quality of the bolt tightening effect will directly affect the normal operation and power generation efficiency of the wind turbine in the future, and the service life of the blade root bolts will directly affect the use and maintenance cost of wind power generation equipment.

[0003] The Chinese patent document with the publication number CN103061995B and the name of "Method for pre-embedding screws at the root of megawatt-class wind turbine blades" and the Chinese patent document with the publication number CN200910049234 and the name of "Method for installing and positioning the root end bolts of megawatt-class wind turbine blades" disclose the structure of the existing root end bolts of wind turbine blades and the corresponding installation method. However, as the length of wind turbine blades becomes longer and the weight of blades becomes heavier, blades with pre-embedded bolt sleeves at the root are increasingly favored by the market due to their strong bearing capacity and small damage to FRP, becoming the mainstream blade root structure. However, the main material of the blade is FRP, which shrinks and deforms during the molding process, and the blade has errors during the mold closing process, which may cause large deviations in the verticality and position of the pre-embedded bolt sleeves. In addition, improper installation methods when splicing blades with variable pitch bearings can also cause misalignment of splicing holes. When encountering the above problems, if the traditional bolts are still used to connect the pitch bearing, the bolts will be tilted, misaligned, etc., causing interference between the bolts and the pitch bearing, bending of the bolts, and additional stress on the bolts, which will eventually lead to bolt breakage. This requires taking necessary preventive control measures in the connection structure design and splicing installation process to adjust the abnormal conditions such as bolt tilt and misalignment, thereby avoiding interference between the bolts, improving the fatigue strength of the bolts, and extending the service life of the bolts. Summary of the invention

[0004] The main purpose of the present invention is to provide a new connection structure between a wind turbine blade and a pitch bearing and a corresponding installation method, so as to effectively prevent the adverse effects caused by the misalignment of the bolts [hereinafter referred to as double-headed screws] connecting the wind turbine blade and the pitch bearing, thereby further extending the service life of the double-headed screws, and further helping to reduce the failure rate of wind power generation equipment.

[0005] The technical scheme used in the novel connection structure of a wind turbine blade and a variable pitch bearing described in the present invention is: a connection structure of a wind turbine blade and a variable pitch bearing, comprising a variable pitch bearing, a wind turbine blade, a double-headed screw and a nut. The wind turbine blade comprises a flange, an embedded bolt sleeve, a blade and an O-type rubber ring. The O-type rubber ring is arranged in the embedded bolt sleeve, and the right end of each double-headed screw passes through the flange and the O-type rubber ring to the right and is threadedly connected with a embedded bolt sleeve, and the outer ring connecting bolt of the variable pitch bearing passes through the outer ring of the variable pitch bearing and is threadedly connected with the wind wheel hub. It also includes a bolt automatic centering device, and the bolt automatic centering device comprises a high round sleeve and a low round sleeve. The right end of the high round sleeve and the left end of the low round sleeve are spherically connected, and the inner hole diameters of the high round sleeve and the low round sleeve are larger than the diameter of the double-headed screw. The left end of the double-headed screw passes through the low round sleeve and the high round sleeve to the left in turn and is threadedly connected with the nut, so that the right end of the high round sleeve and the left end of the low round sleeve are fitted together.

[0006] The present invention ingeniously utilizes the spherical sliding connection between the high round sleeve and the low round sleeve, so that when the verticality and position of the embedded bolt sleeve deviate, the surface of the nut on the side of the high round sleeve can also be parallel to the left side of the high round sleeve, so that the double-headed screw will not be subjected to bending force when tightened, which is beneficial to increasing the service life of the double-headed screw and also beneficial to reducing the failure rate of wind power generation equipment.

[0007] Preferably, when the axis of the high circular sleeve and the axis of the low circular sleeve are collinear, the distance L between the free end face of the high circular sleeve and the free end face of the low circular sleeve is greater than or equal to 30 mm and less than or equal to 60 mm; the right end of the thread of the left end of the double-headed screw is located in the bolt automatic centering device, and the thread of the right end of the double-headed screw is located in the wind turbine blade. In this preferred solution, the centering device increases the length of the double-headed bolt, which is beneficial to improving the service life of the double-headed screw and can also prevent the adverse effects caused by the thread section of the double-headed screw entering the variable pitch bearing.

[0008] It is further preferred that the diameter of the middle polished rod section of the double-headed screw is smaller than the diameter of the threaded sections at both ends, the right end of the middle polished rod section of the double-headed screw is located in the embedded bolt sleeve, and the left end is located in the inner hole of the low round sleeve; the inner ring of the O-type rubber ring and the polished rod part of the double-headed screw are interference-connected, and the outer ring and the inner hole of the embedded bolt sleeve are transitionally matched. The above preferred scheme is conducive to reducing the adverse effects caused by a certain degree of deviation in the verticality and position of the embedded bolt sleeve, and the matching structure of the inner and outer rings of the O-type rubber ring and the polished rod and the inner hole of the embedded bolt sleeve is conducive to ensuring the centering state of the double-headed screw.

[0009] Preferably, the intersection angle α between the inner hole axis of the high circular sleeve and the inner hole axis of the low circular sleeve is less than or equal to 3°. When the intersection angle α between the inner hole axis of the high circular sleeve and the inner hole axis of the low circular sleeve is equal to 3°, the fitting surface of the high circular sleeve and the low circular sleeve does not exceed the corresponding spherical surface area of ​​the low circular sleeve. This preferred solution has a reasonable structure and can well meet the design purpose.

[0010] In summary, the beneficial effects of the connection structure of a wind turbine blade and a pitch bearing of the present invention are as follows: due to the ingenious use of the spherical sliding connection between the high round sleeve and the low round sleeve, when the verticality and position of the embedded bolt sleeve deviate, the surface of the nut on the side of the high round sleeve can also be parallel to the left surface of the high round sleeve, so that the double-headed screw will not be subjected to bending force, which is beneficial to increase the service life of the double-headed screw and reduce the failure rate of wind power generation equipment.

[0011] A method for connecting a wind turbine blade and a pitch bearing together by using the above-mentioned connection structure of the wind turbine blade and the pitch bearing uses the following technical solution:

[0012] 1. Prepare the parts and tools to be assembled;

[0013] 2. Place a wind turbine blade correctly, and use the embedded bolt sleeve at the trailing edge of the blade as a reference to screw a positioning pin into each of the three embedded bolt sleeves at an angle of 120° until it cannot be screwed in;

[0014] 3. Screw the stud screws into the remaining embedded bolt sleeves of the wind turbine blade in sequence. The height of the left ends of all stud screws extending out of the flange of the wind turbine blade is the same, and the height of the positioning pins extending out of the flange is greater than the height of the stud bolts extending out of the flange; apply lubricant on the threads of all stud screws extending out of the flange;

[0015] 4. Lift and move the wind turbine blade, adjust the hole position of the pitch bearing, first insert the left ends of the three positioning pins into the corresponding holes of the pitch bearing, and then continue to push the pitch bearing to the right to the bottom;

[0016] 5. According to the assembly process, put the low round sleeve and high round sleeve of the bolt automatic centering device to the right onto the left end of the corresponding double-headed screw, and then tighten the corresponding nut. Use 50% and 100% standard torque to tighten each nut in a cross-cross order twice;

[0017] 6. Remove the three locating pins connected to the blade, and then according to the assembly process, put the low round sleeve and high round sleeve of the bolt automatic centering device to the right onto the left end of the corresponding double-headed screw at the exit position of these locating pins, and then tighten the corresponding nut. Use 50% and 100% standard torque to tighten the nut twice. At this point, the connection and installation of a wind turbine blade and a variable pitch bearing are completed.

[0018] After the other two wind turbine blades and the corresponding variable pitch bearings are connected and installed according to the above 6 steps, further installation and connection work can be carried out. The above method of connecting the wind turbine blade and the variable pitch bearing together using the connection structure of the wind turbine blade and the variable pitch bearing described in the present application has clear and reasonable steps and high installation quality of the wind turbine blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : Schematic diagram of the connection structure between the wind turbine blade and the pitch bearing;

[0020] Figure 2 : A cross-sectional schematic diagram of the bolt automatic centering device in the connection structure between the wind turbine blade and the pitch bearing when the axes of the high circular sleeve and the low circular sleeve are collinear;

[0021] Figure 3 : Schematic diagram when the axes of the high circular sleeve and the low circular sleeve are not collinear;

[0022] Figure 4 : Schematic diagram of the connection structure of three positioning pins and a blade;

[0023] Figure 5 : Schematic diagram of the connection structure between a double-headed screw, three positioning pins and a blade;

[0024] In the figure: wind rotor hub 1, pitch bearing 2, wind turbine blade 3, flange 3-1, embedded bolt sleeve 3-2, blade 3-3, O-ring 4, double-headed screw 5, bolt automatic centering device 6, high round sleeve 6-1, low round sleeve 6-2, pitch bearing outer ring connecting bolt 7, nut 8, locating pin 9. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0026] An embodiment of a connection structure between a wind turbine blade and a pitch bearing:

[0027] like Figure 1-5As shown, the present invention includes a variable pitch bearing 2, a wind turbine blade 3, a double-headed screw 5, and a nut 8. The wind turbine blade 3 includes a flange 3-1, an embedded bolt sleeve 3-2, a blade 3-3, and an O-type rubber ring 4. The O-type rubber ring 4 is arranged in the embedded bolt sleeve 3-2. The more specific structural details of the wind turbine blade 3 are known technologies and are not described here. The right end of each double-headed screw 5 passes through the flange 3-1 and the O-type rubber ring 4 to the right and is threadedly connected to an embedded bolt sleeve 3-2. The variable pitch bearing outer ring connecting bolt 7 passes through the outer ring of the variable pitch bearing 2 and is threadedly connected to the wind rotor hub 1. In addition, it also includes a bolt automatic centering device 6, which includes a high round sleeve 6-1 and a low round sleeve 6-2. The right end of the high round sleeve 6-1 and the left end of the low round sleeve 6-2 are spherically connected. The inner hole diameter of the high round sleeve 6-1 and the low round sleeve 6-2 is larger than the diameter of the double-headed screw 5. The left end of the double-headed screw 5 passes through the low round sleeve 6-2 and the high round sleeve 6-1 to the left in turn and is threadedly connected with the nut 8, so that the right end of the high round sleeve 6-1 and the left end of the low round sleeve 6-2 are fitted together. When the axis of the high circular sleeve 6-1 and the axis of the low circular sleeve 6-2 are collinear, the distance L between the free end faces of the high circular sleeve 6-1 and the free end faces of the low circular sleeve 6-2 is not less than 60 mm; the right end of the thread of the left end of the double-headed screw 5 is located in the inner hole of the high circular sleeve 6-1; in addition, the outer diameter of the high circular sleeve 6-1 is smaller than the outer diameter of the low circular sleeve 6-2, and the intersection angle α between the inner hole axis of the high circular sleeve 6-1 and the inner hole axis of the low circular sleeve 6-2 is less than or equal to 3°. When the intersection angle α between the inner hole axis of the high circular sleeve 6-1 and the inner hole axis of the low circular sleeve 6-2 is equal to 3°, the fitting surface of the high circular sleeve 6-1 and the low circular sleeve 6-2 does not exceed the corresponding spherical area of ​​the low circular sleeve 6-2.

[0028] Preferably, the diameter of the middle polished rod section of the double-headed screw 5 is smaller than the diameter of the threaded sections at both ends, the right end of the middle polished rod section of the double-headed screw 5 is located in the embedded bolt sleeve 3-2, and the left end is located in the inner hole of the low round sleeve 6-2. The left end of the threaded section at the right end of the double-headed screw 5 and the right end of the middle polished rod section of the double-headed screw 5 are connected through a truncated cone-shaped left transition section with a right end diameter greater than the left end diameter, and the right end of the threaded section at the left end of the double-headed screw 5 is connected through a right transition section with a left end diameter greater than the right end diameter. The inner ring of the O-type rubber ring 4 is interference-connected with the polished rod part of the double-headed screw 5, and the outer ring is transitionally matched with the inner hole of the embedded bolt sleeve 3-2.

[0029] Embodiment of a method for connecting a wind turbine blade and a pitch bearing together by using a connection structure of the wind turbine blade and the pitch bearing:

[0030] 1. Prepare the parts and tools to be assembled;

[0031] 2. Place a wind turbine blade 3 correctly, and use the embedded bolt sleeve 3-2 at the trailing edge of the blade 3-3 as a reference to screw a locating pin 9 into each of the three embedded bolt sleeves 3-2 at an angle of 120° until it cannot be screwed in; the screwing end of the locating pin 9 is a conical external thread that can be matched with the thread in the embedded bolt sleeve 3-2, and the other end has a wrench bayonet. The middle section 9-2 of the locating pin can simultaneously be clearance-matched with the mounting hole of the variable pitch bearing 2 and the inner hole of the embedded bolt sleeve 3-2, and the clearance is 0.2~0.3mm;

[0032] 3. Screw the stud screws 5 into the remaining embedded bolt sleeves 3-2 of the wind turbine blade 3 in sequence. The height of the left ends of all stud screws 5 extending out of the flange 3-1 of the wind turbine blade is the same [denoted as H]. The height of the positioning pin extending out of the flange is greater than the height of the stud bolt extending out of the flange [H+50 in this embodiment]. Apply lubricant to the threads of all stud screws 5 extending out of the flange.

[0033] 4. Lift and move the wind turbine blade 3, adjust the hole position of the pitch bearing 2, first insert the left ends of the three positioning pins 9 into the corresponding holes of the pitch bearing 2, and then continue to push the pitch bearing 2 to the right to the bottom;

[0034] 5. According to the assembly process, the low round sleeve 6-2 and the high round sleeve 6-1 of the bolt automatic centering device 6 are put rightward onto the left end of the corresponding double-headed screw 5, and then the corresponding nut 8 is screwed on. Use 50% and 100% standard torques to tighten each nut in a cross-cross order twice;

[0035] 6. Remove the three locating pins 9 connected to the blade, and then in the withdrawal position of these locating pins, according to the assembly process, put the low round sleeve 6-2 and the high round sleeve 6-1 of the bolt automatic centering device 6 to the right onto the left end of the corresponding double-headed screw 5, and then screw on the corresponding nut 8, using 50% and 100% standard torque, tighten the nut 8 twice; at this point, the connection and installation of a wind turbine blade 3 and a variable pitch bearing 2 are completed.

[0036] The lengths or distances not specified above are in millimeters. The specific embodiments described are only preferred embodiments of the present invention, and are not intended to limit the specific implementation structure and implementation scope of the present invention. In fact, some equivalent changes can also be made according to the shape, structure and design purpose described in the present invention. Therefore, all equivalent changes made according to the shape, structure and design purpose described in the present invention should be included in the protection scope of the present invention, that is, these equivalent changes should be protected by the present invention.

Claims

1. A connection structure between a wind turbine blade and a pitch bearing, comprising a pitch bearing (2), a wind turbine blade (3), a double-headed screw (5), and a nut (8); the wind turbine blade (3) comprises a flange (3-1), an embedded bolt sleeve (3-2), a blade (3-3), and an O-type rubber ring (4); the O-type rubber ring (4) is arranged in the embedded bolt sleeve (3-2); the right end of each double-headed screw (5) passes through the flange (3-1) and the O-type rubber ring (4) to the right and is then threadedly connected to a embedded bolt sleeve (3-2); the outer ring connecting bolt (7) of the pitch bearing passes through the outer ring of the pitch bearing (2) and is then threadedly connected to the wind rotor hub (1); the characteristics are: The invention also comprises an automatic bolt centering device (6), wherein the automatic bolt centering device (6) comprises a high round sleeve (6-1) and a low round sleeve (6-2); the right end of the high round sleeve (6-1) and the left end of the low round sleeve (6-2) are spherically connected to each other; the inner diameters of the high round sleeve (6-1) and the low round sleeve (6-2) are larger than the diameter of the double-headed screw (5); the left end of the double-headed screw (5) passes through the low round sleeve (6-2) and the high round sleeve (6-1) in sequence to the left, and then is threadedly connected to the nut (8); the high round sleeve (6-1) The right end of the double-headed screw and the left end of the low round sleeve (6-2) are fitted together; the intersection angle α of the inner hole axis of the high round sleeve and the inner hole axis of the low round sleeve is less than or equal to 3°, when α is equal to 3°, the fitting surface of the high round sleeve and the low round sleeve does not exceed the corresponding spherical area of ​​the low round sleeve; the left end of the threaded section at the right end of the double-headed screw and the right end of the middle bare rod section of the double-headed screw are connected through a truncated cone-shaped left transition section with a right end diameter greater than the left end diameter, and the right end of the threaded section at the left end of the double-headed screw is connected through a right transition section with a left end diameter greater than the right end diameter.

2. The connection structure between a wind turbine blade and a pitch bearing according to claim 1 is characterized in that: When the axis of the high circular sleeve (6-1) and the axis of the low circular sleeve (6-2) are collinear, the distance L between the free end surface of the high circular sleeve (6-1) and the free end surface of the low circular sleeve (6-2) is greater than or equal to 30 mm and less than or equal to 60 mm; the right end of the thread at the left end of the double-headed screw is located in the bolt automatic centering device, and the thread at the right end of the double-headed screw is located in the wind turbine blade.

3. The connection structure between a wind turbine blade and a pitch bearing according to claim 1 is characterized in that: The diameter of the middle polished rod section of the double-ended screw rod (5) is smaller than the diameters of the threaded sections at both ends. The right end of the middle polished rod section of the double-ended screw rod (5) is located in the embedded bolt sleeve (3-2), and the left end is located in the inner hole of the low circular sleeve (6-2).

4. The connection structure between a wind turbine blade and a pitch bearing according to claim 1 is characterized in that: The inner ring of the O-type rubber ring (4) and the smooth rod part of the double-headed screw (5) are in interference connection, and the outer ring and the inner hole of the embedded bolt sleeve (3-2) are in transition fit.

5. The connection structure between a wind turbine blade and a pitch bearing according to claim 1 is characterized in that: The inner ring of the O-type rubber ring and the smooth rod part of the stud screw 5 are in interference connection, and the outer ring and the inner hole of the embedded bolt sleeve are in transition fit.

6. A method for connecting a wind turbine blade and a pitch bearing together using any one of claims 1 to 5, characterized in that: (1) Prepare the parts and tools required for assembly; (2) A wind turbine blade (3) is correctly placed, and a positioning pin (9) is screwed into each of three embedded bolt sleeves (3-2) at an angle of 120°, using the embedded bolt sleeve (3-2) at the trailing edge of the blade (3-3) as a reference, until it cannot be screwed in any further; (3) Screw the stud screws (5) into the remaining embedded bolt sleeves (3-2) of the wind turbine blade (3) in sequence, so that the left ends of all stud screws (5) extend out of the flange (3-1) of the wind turbine blade to the same height, and the height of the positioning pins extending out of the flange is greater than the height of the stud bolts extending out of the flange; apply lubricant to the threads of all stud screws (5) extending out of the flange; (4) lifting and moving the wind turbine blade (3), adjusting the hole position of the variable pitch bearing (2), first inserting the left ends of the three positioning pins (9) into the corresponding holes of the variable pitch bearing (2), and then pushing the variable pitch bearing (2) further to the right to the bottom; (5) According to the assembly process, the low round sleeve (6-2) and the high round sleeve (6-1) of the bolt automatic centering device (6) are put rightward onto the left end of the corresponding double-headed screw (5), and then the corresponding nut (8) is screwed on. The nuts are tightened in a cross-shaped order twice using 50% and 100% standard torques; (6) Remove the three positioning pins (9) connected to the blade, and then, in the position where the positioning pins are withdrawn, in accordance with the assembly process, put the low round sleeve (6-2) and the high round sleeve (6-1) of the bolt automatic centering device (6) to the right onto the left end of the corresponding double-headed screw (5), and then screw on the corresponding nut (8), using 50% and 100% standard torques to tighten the nut twice; thus, the connection and installation of a wind turbine blade (3) and a variable pitch bearing (2) are completed.

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