A method for embedding a bolt sleeve in a wind turbine blade outer surface region by means of resin infusion

Abstract

The application belongs to the technical field of wind power blade manufacturing, and specifically discloses a kind of pouring forming methods of wind power blade outer surface area embedded bolt sleeve, including flange sealing, bolt sleeve fixing, vacuum pressure preservation, pouring curing, film tearing and blade root cutting and the like steps;Compared with the prior art, the application has the advantages of effectively improving the bolt sleeve installation precision, reducing the air leakage risk during vacuum pouring, avoiding the glass fiber cloth layer wrinkle defect, and simplifying the turning operation of double-sided pouring, thereby improving the blade structure integrity and production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of wind turbine blade manufacturing technology, and in particular relates to a method for injection molding of pre-embedded bolt sleeves on the outer surface of wind turbine blades. Background Technology

[0002] As a core component of wind power generation systems, large wind turbine blades require a reliable connection to the hub via high-strength bolts at their root region. The stability of this connection strength directly determines the overall safety and durability of the wind turbine. In special applications, such as the manufacturing process of test blades or blade tips, bolt sleeves must be pre-embedded at specific locations on the blade, such as the root of the blade tip, to support the subsequent installation of test flanges for critical verification work such as static testing and fatigue testing.

[0003] However, the installation process of pre-embedded bolt sleeves faces significant challenges in actual production. The large size and highly complex three-dimensional curved surface of wind turbine blades make it difficult to effectively control the perpendicularity and radial position accuracy of the bolt sleeves when precisely placing a large number of bolt sleeves on the curved shell. Even minor deviations can lead to connection structure failure. Simultaneously, the complex gap structure formed between the bolt sleeves and the blade shell, and between the pre-installed steel flange and the blade, is prone to air leakage during vacuum resin injection, causing uneven resin flow, incomplete injection, or internal defects, seriously threatening the integrity of the blade structure. Furthermore, the fiberglass cloth layer around the bolt sleeves is prone to wrinkles and gaps during installation, hindering the resin from fully impregnating the composite matrix, significantly weakening the bond strength between the bolt sleeve and the matrix, and thus affecting the mechanical properties of the pre-embedded area. For areas requiring pre-embedded bolt sleeves on both sides, traditional processes are lengthy, and flipping operations are not only difficult to implement but also prone to damaging the already formed surface during secondary operations, leading to reduced production efficiency and increased manufacturing costs. These problems collectively restrict the reliability of pre-embedded bolt sleeve installation and the overall quality of the blade.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a method for pre-embedded bolt sleeves on the outer surface of wind turbine blades through injection molding. This method can effectively improve the installation accuracy of bolt sleeves, reduce the risk of air leakage during vacuum injection, avoid defects such as wrinkles in the fiberglass cloth layer, and simplify the flipping operation of double-sided injection, thereby improving the structural integrity and production efficiency of the blade. This solves the problems of low installation accuracy of bolt sleeves, vacuum leakage, cloth layer defects, and difficulty in flipping in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: a method for injection molding of pre-embedded bolt sleeves on the outer surface area of ​​wind turbine blades, comprising the following steps:

[0007] S1. Blade preparation: Use a setting gauge to mark the horizontal meter mark on the ground, set up the SS surface support fixture on the ground according to the horizontal meter mark, then place the blade on the SS surface support fixture with the PS surface facing up, and verify the blade placement position with another setting gauge.

[0008] S2. Flange tooling preparation and end face sealing: The flange tooling includes the flange body and the flange bracket for fixing the flange body. The flange tooling is assembled at the blade root position, and the gap between the blade and the flange body in the flange tooling is sealed and connected using sealant.

[0009] S3. Grinding and laying the bolt sleeve underlayer and continuous felt: Grind and clean the surface of the blade root and the flange body. Then lay the set number of underlayers on the blade surface from bottom to top. After the underlayers are laid, lay the continuous felt according to the data in the layup table.

[0010] S4. Laying pre-embedded bolt sleeves, wedge blocks, and UD bars: Clean the flange hole of the flange body, place a sealing ring inside the flange hole, and set the bolt sleeve at the blade root position with the root of the bolt sleeve attached to the flange body. Use positioning bolts to fix the bolt sleeve based on the flange hole. After fixing, place the UD bar next to the bolt sleeve with it attached to the radial outer surface of the bolt sleeve, and lay a wedge block at the tip of the bolt sleeve. Fix the set number of bolt sleeves in sequence from the middle to both sides.

[0011] S5. Lay the upper layer of the bolt sleeve: Lay another set number of upper layers of fabric from bottom to top. After the upper layers of fabric are laid, lay the continuous felt according to the data in the layer laying table.

[0012] S6. Laying the release fabric and injecting auxiliary materials: Cover the area where the upper fabric is laid with the release fabric; lay a composite flow guide net on the surface of the release fabric; set up suction bags at the blade root, leading edge parting line and trailing edge parting line respectively, and connect the suction bags to the external suction pipeline; lay multiple injection pipelines from the leading edge to the trailing edge of the blade, and each injection pipeline extends along the chord of the blade.

[0013] S7. Arrange the air extraction system: Use release cloth to wrap the spiral tube as an air extraction pipe, and set the air extraction pipes at the front edge and the rear edge respectively.

[0014] S8. Vacuum Pressure Holding: Lay the primary sealing vacuum bag film on the surface of the blade from the blade root to the blade tip. Turn on the vacuum pump to evacuate the primary vacuum bag film. After the primary vacuum bag film is tightened and the vacuum pump reading is ≥83kPa, lay the secondary sealing vacuum bag film and place a guide net between the primary and secondary sealing vacuum bag films. Then, perform a secondary vacuum evacuation. When the vacuum degree reaches below 30mbar, start the pressure holding test.

[0015] S9. Injection and Curing: After the pressure holding test is passed, the injection pipeline is vented. After the venting time is set, the glass fiber resin is injected. Before the injection is completed, the heater is turned on and the heating temperature is gradually increased to the set temperature to heat the glass fiber resin until the glass fiber resin is cured, thus completing the injection molding of the PS surface of the blade.

[0016] S10. Film Removal and Blade Flipping: After heat curing, test the surface hardness of the heat-cured area of ​​the blade every 1m. If the surface hardness is above 60HD, remove the film from the blade when the surface temperature is below 45℃. If the hardness of the heat-cured area is below 60HD, reheat and cure the area until the hardness meets the standard, then remove the film. After removing the film, disconnect the flange body from the flange bracket, flip the blade to the SS side facing upwards, and flip the flange body synchronously. Replace the SS side bracket fixture with the PS side bracket fixture, place the flipped blade in the PS side bracket fixture, and then reconnect and fix the flange body to the flange bracket.

[0017] S11. Repeat steps S3 to S9 to complete the SS surface injection molding of the blade, and perform a film removal process on the injection molded SS surface.

[0018] S12, Blade Root Cutting: Disconnect the flange body from the flange bracket, flip the blade so that the PS face is facing upwards, and the flange body flips synchronously with it; replace the PS face bracket fixture with the SS face bracket fixture, and place the flipped blade on the SS face bracket fixture, and then reconnect and fix the flange body to the flange bracket; after the blade is placed stably, remove the flange fixture as a whole.

[0019] Furthermore, the flange body consists of a PS face flange and an SS face flange. The assembly of the flange fixture includes the following steps: first, connect the SS face flange to the flange bracket, and place the flange bracket with the SS face flange at the blade root position; then, overlap and snap the PS face flange onto the top of the SS face flange from top to bottom, and connect the PS face flange to the bracket; finally, connect the PS face flange and the SS face flange using a connecting plate.

[0020] Furthermore, in step S3, the lower fabric layers are arranged in a staggered manner from bottom to top, and the chordal stagger distance between any two adjacent lower fabric layers is 3-5mm.

[0021] Furthermore, in step S6, along the axial direction, the distance from the guide net to the flange body is 60-100mm; along the chord direction, the distance from the guide net to the front parting line is 50-100mm; and the distance from the guide net to the rear parting line is 50-100mm.

[0022] Furthermore, in step S6, the pipe spacing between any two adjacent glue injection lines is 400mm, and each glue injection line is provided with at least one glue injection port.

[0023] Furthermore, in step S6, the glue injection pipeline is configured as three pipelines, namely pipeline I, pipeline II and pipeline III, which are laid sequentially from the leading edge to the trailing edge of the blade, with pipeline II located at the highest point of the blade.

[0024] The beneficial effects of this technical solution are as follows:

[0025] This invention discloses a method for injection molding of pre-embedded bolt sleeves on the outer surface of wind turbine blades. Through steps such as flange sealing, bolt sleeve fixing, vacuum pressure holding, injection curing, film peeling and flipping, and blade root cutting, it effectively solves the problems of low bolt sleeve installation accuracy, vacuum leakage, layer defects, and difficulty in flipping. Using a split flange body as the installation reference, combined with a bolt sleeve pre-embedding sequence "from the center to both sides," and further enhanced by UD rod limiting and wedge-shaped block filling processes, it effectively ensures the axial perpendicularity, radial position accuracy, and tight fit with the fiber layer of each pre-embedded bolt sleeve, greatly improving the positioning accuracy and final connection strength of the pre-embedded parts. A circumferential seal is used at the blade end. The dual-sealing structure with independent sealing on each side, combined with a double vacuuming process, effectively solves the problem of vacuum leakage under complex structures and ensures the stability of the injection process. The refined layup design and strict gap control ensure that the resin can fully wet every layer of fiber around the bolt sleeve, avoiding dry yarn and pores, so that the bolt sleeve and the composite matrix form a high-strength whole. The double-sided pre-embedding operation is decomposed into two symmetrical and standard single-sided processes (PS side and SS side), which are achieved by flipping the blade as a whole. The process is clear, the operation difficulty is reduced, and the repeatability and production efficiency of the process are improved. It is especially suitable for the construction of pre-embedded parts on the outer surface of special parts such as the tip of large wind turbine blades.

[0026] Compared with existing technologies, this invention has the advantages of effectively improving the installation accuracy of bolt sleeves, reducing the risk of air leakage during vacuum injection, avoiding defects such as wrinkles in the fiberglass cloth layer, and simplifying the flipping operation of double-sided injection, thereby improving the structural integrity of the blade and production efficiency. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to the present invention.

[0028] Figure 2 This is a schematic diagram of the end face sealing between the flange body and the blade of the present invention. Figure 3 This is a schematic diagram showing the arrangement and fit between the UD rod and the wedge block of the present invention; Figure 4 This is a schematic diagram of the structure of the UD rod of the present invention. Detailed Implementation

[0029] The following detailed description illustrates the specific implementation method:

[0030] The reference numerals in the accompanying drawings include: blade 1, flange body 2, flange hole 201, sealant 3, flange cavity 4, bolt sleeve 5, UD bar 6, and wedge block 7.

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The basic implementation examples are as follows: Figure 1-2 The following is illustrated: A method for injection molding of pre-embedded bolt sleeves on the outer surface of a wind turbine blade, the method specifically including the following steps:

[0033] S1. Leaf preparation:

[0034] S1.1 First, prepare a measuring tool with sufficient range, such as a tape measure of 50m or more. Use the measuring tool to mark the horizontal meter mark on the ground. The SS surface support fixture itself also has meter markings. According to the horizontal meter mark and in conjunction with the meter markings on the SS surface support fixture, set up the SS surface support fixture on the ground. At least two SS surface support fixtures should be set up. Take measurements from the front and rear edges of the meter markings on both fixtures using the measuring tool on at least two sides to ensure the correct axial angle of the support fixture.

[0035] S1.2. Place blade 1 with its PS side facing upwards on the SS surface support fixture, and measure the angle at the highest point of the blade 1 profile corresponding to the aforementioned support using another set measuring tool. Verify the angle value; if there is a discrepancy, adjust the four legs of each SS surface support fixture to approach the theoretical value. The other set measuring tool can be an angle measuring instrument, a tape measure, or a laser measuring instrument, etc. The specific selection of measuring tools, as well as the measurement and adjustment methods, are all applications of existing technology here, and therefore will not be elaborated. If it is difficult to accurately determine the meter value during on-site adjustment, the current meter cross-section can be compared with the theoretical cross-section diagram to determine whether cutting can be performed in the current posture. If the difference is too large, the position of blade 1 needs to be readjusted, which is understandable to those skilled in the art and will not be elaborated here.

[0036] S2. Flange tooling preparation and end face sealing:

[0037] S2.1 Flange Fixture Preparation: Specifically, the flange fixture in this embodiment includes a flange body 2 and a flange bracket for fixing the flange body 2. The flange body 2 is composed of a PS face flange and an SS face flange. The flange body 2 has flange holes 201 along its circumference for fixing and positioning bolt sleeves 5. The central area of ​​the flange body 2 is a flange cavity 4, which corresponds to the central cavity of the blade 1. At the same time, the flange cavity 4 in the flange body 2 also facilitates the subsequent end face sealing of the blade 1. The assembly of the flange fixture includes the following steps:

[0038] First, connect the SS flange to the flange bracket, and place the flange bracket with the SS flange at the blade root position of blade 1; overlap and snap the PS flange onto the top of the SS flange from top to bottom, and connect the PS flange to the bracket; use a connecting plate to connect the PS flange and the SS flange; assemble the flange fixture at the blade root position of blade 1, and use sealant 3 to seal the gap between blade 1 and the flange body 2 in the flange fixture; in this embodiment, the flange bracket is also two separate parts, which are fixed by the transverse sides of the flange body 2 (that is, the chordal sides of blade 1), and the fixing method can be bolt connection, snap connection, or other connection methods that are easy to disassemble.

[0039] S2.2 End Face Sealing: After the flange fixture is assembled, structural adhesive is used to seal the gap between the flange body 2 and the end face corresponding to the blade root of the blade 1, and a radius (R) is reserved. Thus, the flange body 2 not only forms an circumferential seal at the blade root position, but the split flange body 2 also achieves independent sealing of the end face of the blade 1. This double sealing structure effectively solves the problem of vacuum leakage under complex structures and ensures the stability of the injection process.

[0040] S3. Grind and lay the bolt sleeve under the fabric layer and continuous felt:

[0041] S3.1 Use a grinder to grind the surface at the blade root and the surface of the flange body 2. The grinding process should not miss any areas. Grind until the surface is no longer shiny. Clean up the site after grinding.

[0042] S3.2. Lay a predetermined number of lower fabric layers sequentially from bottom to top on the surface of blade 1. The first layer of the lower fabric layer is laid from the leading edge parting line to the trailing edge parting line of blade 1. Subsequent layers are laid in staggered layers from bottom to top. Any connected lower fabric layers are staggered chordally by 3-5mm, preferably by 4mm. "Staggered chordally" means that the chordal width of the lower fabric layer decreases by 3-5mm from bottom to top, and the central axis of all lower fabric layers is coaxial. This is understandable to those skilled in the art and will not be elaborated here. During the laying process, roll each lower fabric layer flat to ensure it is flat and wrinkle-free. Use an appropriate amount of spray adhesive to fix the lower fabric layer to the edge near the flange body 2. The lower fabric layer can be fiberglass cloth or other materials.

[0043] S3.3 Laying Continuous Felt: Lay the continuous felt according to the layup table data. The continuous felt is laid circumferentially along blade 1, with staggered transitions during layup. The staggered layers are trimmed at the beginning and end positions of the continuous felt. As a preferred embodiment, in this example, one staggered layer is trimmed for every 100g of continuous felt, for a total of two staggered layers. The staggered layer width is 50mm, and the total staggered layer width is 100mm. The rounded corners between the flange body 2 and the fabric layer can be filled with UD yarn bundles.

[0044] S4, Lay out the pre-embedded bolt sleeve 5, wedge block 7 and UD rod 6:

[0045] S4.1 First bolt sleeve 5 installation:

[0046] S4.1.1 Remove the release cloth at flange hole 201 and clean the glass fiber filaments inside the hole;

[0047] S4.1.2 First, install several bolt sleeves 5 within the radius to check and measure the gap between the bolt sleeve 5 and the glass fiber below. If the gap is greater than 1mm, lay a cloth layer of the same specification as the lower cloth layer under the bolt sleeve 5 to fill the gap.

[0048] S4.1.3. Place the O-ring into the flange hole 201 of the flange body 2, and place the root of the bolt sleeve 5 close to the steel flange. One person holds the bolt sleeve 5 and makes it close to the flange body 2, while another person inserts the positioning bolt through the flange hole 201 into the bolt sleeve 5. First, manually tighten the bolt, and then use a pneumatic wrench or torque wrench to tighten it. After the bolt sleeve 5 is fixed, place a UD rod 6 on each side of the bolt sleeve 5 along the chord direction. The UD rod 6 is close to the flange body 2, and a wedge block 7 is placed at the tip of the bolt sleeve 5 with the arc surface of the wedge block 7 facing down. The gap between the wedge block 7 and the plug of the bolt sleeve 5 is ≤1mm. UD yarn can be placed in the gap between the unwound area of ​​the bolt sleeve 5 and the UD rod 6. Specifically, UD rod 6 is used to limit and position the bolt sleeve 5 in the chord direction. The axial portion of UD rod 6 is conformable to the bolt sleeve 5, and the remaining axial portion is conformable to the wedge block 7. The two UD rods 6 limit the bolt sleeve 5 in the chord direction. After installation, the wedge block 7 limits and positions the bolt sleeve 5 in the axial direction, and the wedge block 7 is also limited in the chord direction by the two UD rods 6. UD rod 6 is set as a chordally symmetrical structure to ensure bidirectional limiting. Unless otherwise specified, in this embodiment, the root refers to the end facing the blade root 1 after installation, and the tip refers to the end facing the blade tip 1 after installation.

[0049] S4.2 Repeat step 4.1, fixing the bolt sleeves sequentially from the middle to both sides until the number of bolt sleeves reaches the set number. Since the UD rod 6 of the first bolt sleeve 5 is set on both sides, when fixing the remaining bolt sleeves 5, only one side needs to be set to form a structure where there is only one UD rod 6 between any two adjacent bolt sleeves 5. At the same time, each bolt sleeve 5 is clamped by two UD rods 6. At the front and rear edge positions, that is, at the end bolt sleeve 5 positions, a single-sided UD block is used for finishing.

[0050] S5. Lay the upper fabric layer of the bolt sleeve: Lay another set number of upper fabric layers from bottom to top. After the upper fabric layers are laid, lay the continuous felt according to the data in the layer laying table. The setting method of the upper fabric and the continuous felt here is the same as in step S3, so it will not be described again.

[0051] S6. Lay out the release liner and pour in the auxiliary materials:

[0052] S6.1 Laying the release fabric: Cover the laying area of ​​the upper fabric with the release fabric, and lay it in the tangential direction, that is, the surface of the fabric layer in the laying area is fully covered with the release fabric.

[0053] S6.2 Laying the Composite Flow Guide Net: Lay the composite flow guide net on the surface of the release fabric. The axial distance of the flow guide net from the flange body is 280mm, and the chordal distance from the front and rear parting lines is 50-100mm, for example, 60mm, 70mm, 80mm, or 90mm. As a preferred embodiment, the composite flow guide net is cut with a 50mm width at the middle position corresponding to the three injection tubes.

[0054] S6.3 Laying VAP membrane vacuum bags: A 150mm wide VAP membrane vacuum bag (or a spiral tube) is laid circumferentially around the blade root for vacuuming the blade root end face. 150mm wide VAP membrane vacuum bags are also laid at the front and rear parting lines. The VAP membrane vacuum bags are connected to external vacuum lines for vacuuming.

[0055] S6.4 Laying the Injection Pipeline: Three injection pipelines are set up. The three injection pipelines are pipeline I, pipeline II and pipeline III, which are laid sequentially from the leading edge to the trailing edge of blade 1. The injection is carried out using tangential pipelines. The pipeline spacing is preferably 400mm. Pipeline II is set at the highest point of blade 1. The injection pipeline uses Ω19mm ohmic tubes with built-in pads. The end of the ohmic tube (the end from which the composite resin flows out) and the injection seat (set at the inlet of the injection pipeline, serving as the starting interface for the injection of composite resin, is a rigid connector used to connect the external injection pipeline and the internal injection pipeline) are covered with a layer of breathable cotton or fiberglass cloth to prevent scratching the bag film.

[0056] S7. Arrange the air extraction system: Use release cloth to wrap the spiral tube as an air extraction pipe, and set the air extraction pipes at the front edge and the rear edge respectively; before placing the spiral tube, pull the tube slightly to ensure that the gap of the spiral tube and the air extraction process are uniform.

[0057] S8, Vacuum Pressure Holding:

[0058] S8.1. Spread the first-sealed vacuum bag film evenly over the surface of leaf 1 along the direction from leaf root to leaf tip;

[0059] S8.2, Primary Vacuum: Turn on the primary vacuum pump to evacuate the primary sealing vacuum bag film. After the primary sealing vacuum bag film is tightened, when the vacuum pump reading is ≥83kPa, lay the secondary sealing vacuum bag film. Set a guide net or breathable felt between the primary and secondary sealing vacuum bag films. The guide net or breathable felt is laid in a "Z" shape connecting the front and rear edges of blade 1 and extending from the root of the fabric layer to the tip of the fabric layer to facilitate the evacuation of the secondary sealing vacuum bag film. When laying, avoid the 0-50mm area at the root and the evacuation bag window area to facilitate the observation of the resin flow. The evacuation port of the second bag film uses an external vacuum at the front and rear edges 1m away and in the blade tip area inside the cavity.

[0060] S8.3 Secondary Pressure Holding: After the secondary sealing vacuum bag membrane is arranged, insert the steel wire hose into the glue injection seat. Seal the joint between the glue injection seat and the steel wire hose with three strips of high-temperature resistant sealant, and then tighten it with a hose clamp. The three strips of sealant must not be wrapped around the hose clamp. After the connection is completed, turn on the secondary vacuum pump to evacuate the vacuum. When the vacuum gauge reading is less than 30 mbar, close the valves of the primary and secondary vacuum pumps, keep all air extraction ports open, and start the pressure holding process. The pressure holding rule is that the change in pressure should not exceed 15 mbar every 10 minutes.

[0061] S9. Pouring and Curing:

[0062] S9.1 The vacuum pump is turned on and in manual mode, and all evacuation valves are open.

[0063] S9.2 After successful pressure holding, venting should be carried out for more than 20 minutes before injection. The temperature of the glass fiber should be controlled at 20℃-30℃, and the temperature of the glass fiber resin after mixing the glass fiber and resin should be controlled at 23℃-28℃. Prepare the resin according to the injection operation specifications and transfer the glue bucket to the root of blade 1.

[0064] The specific method for venting is as follows: Slowly open the valve of the injection port, and close it immediately after the resin flows into the injection port to remove the gas in the injection tube. After venting for 3-5 minutes, open injection tube II to start injection. Within 0-20 minutes, open the tube to 1 / 2 size. After 20 minutes, open the tube to inject the full amount. During the injection process, measure the temperature of the resin in the resin tank every 10 minutes. When the temperature of the resin in the resin tank is higher than 37℃, the resin must be replaced with new resin.

[0065] S9.4 When the glass fiber resin exceeds the injection tube I or injection tube III by 50mm, open the corresponding injection tube to start injection.

[0066] S9.5 After all the glass fiber resin has reached the set parting surface, close the injection valves in sequence, use vacuum bag film to make a bag to seal all injection valves and injection seats, and hang the injection tube (steel wire tube) upright to collect air bubbles.

[0067] S9.6. Turn on the heater 20 minutes before the injection is completed. The temperature is gradually increased from the set preheating temperature to 65℃ to heat the glass fiber resin. The specific heating time can be extended or shortened according to the surface hardness.

[0068] S9.7 During the curing process, press the sealant strip 3 on the flange body 2 continuously to prevent air leakage in the flange body 2 area;

[0069] S9.8 Before the heat release peak, the temperature of the fabric layer and blade mold 1 shall be checked and recorded every 30 minutes. Near the heat release peak, the temperature of the fabric layer at the blade root position shall be checked and recorded every 15 minutes. After the heat release peak, the temperature of the fabric layer and blade mold 1 shall be checked and recorded every 30 minutes. When the surface temperature of the fabric layer reaches 45℃-50℃, the corresponding insulation wrapping material, such as insulation blanket or heat insulation blanket, shall be removed.

[0070] Once the fiberglass resin has fully cured, the 1PS surface of the blade is cast and molded.

[0071] S10, Film tearing and blade 1 flipping:

[0072] S10.1 After heating is completed, test the hardness of the surface of the heated and cured area of ​​blade 1 every 1 meter. The film can be peeled off only when the Shore hardness reaches 60HD or above and the surface temperature of the product drops below 45℃. The Tg (DSC median) is ≥70℃. Areas that do not meet the Shore hardness requirements should be reheated and cured until the hardness meets the standard before the film can be peeled off.

[0073] S10.2 Test the hardness of the fabric layer. After the test is passed, turn off the vacuum system and remove the vacuum bag film and the flow channel system such as the glue injection pipeline. During the cleaning of the above auxiliary materials, due to the thinness of the fabric layer at the blade tip edge, do not damage the fabric layer structure. Unless otherwise specified, the fabric layer in this embodiment refers to the collective term for the pre-embedded layer structure such as the upper and lower fabric layers. Testing the hardness of the fabric layer includes, but is not limited to, evaluating the hardness (degree of curing) and interlayer bonding strength of the composite material after curing. Those skilled in the art can adjust the specific test items according to the actual situation, which is understandable to those skilled in the art and will not be elaborated here.

[0074] S10.3 After the film is removed, disconnect the flange body 2 from the flange bracket.

[0075] S10.4 Flip the blade 1 so that the SS side is facing up. The flange body 2 will rotate synchronously. Before flipping, a foam pad on the support needs to be added to prevent the blade 1 from being damaged by the support surface, or the blade 1 can be placed directly on a large foam or other soft support object.

[0076] S10.5 Place the flipped blade 1 onto the PS surface support fixture;

[0077] S10.6 Next, with blade 1 facing upwards on the SS side, reconnect and fix the flange body 2 to the flange bracket.

[0078] S11. Repeat steps S3 to S9 to complete the SS surface injection molding of blade 1, and perform a film removal process on the injection molded SS surface; specifically, the fabric layers are laid and bolt sleeves 5 are fixed on the SS surface in the same order, and the fabric layers on the SS surface are injected and cured in the order of the previous side. This is understandable to those skilled in the art and will not be elaborated here.

[0079] S12, Blade Root Cutting: Disconnect the flange body 2 from the flange bracket, flip the blade 1 so that the PS side is facing upwards, and the flange body 2 flips synchronously. Before flipping, a foam pad needs to be added to the bracket to prevent the blade 1 from being damaged by the bracket surface, or the blade 1 can be placed directly on a large foam or other soft support object; replace the PS side bracket fixture with the SS side bracket fixture, and place the flipped blade 1 on the SS side bracket fixture, and then reconnect and fix the flange body 2 to the flange bracket; after the blade 1 is placed stably, remove the flange fixture as a whole.

[0080] S13. Transportation readiness:

[0081] Add sleepers under the SS surface support fixture on the side of blade 1 closest to the blade root to raise the blade root. Rotate blade 1 as a whole in the vertical plane by 1-2° so that the blade tip moves vertically downward. Measure the height of the blade tip from the ground. It should be less than 3500mm. If it does not meet the requirement, adjust (add) the number of sleepers to meet the requirement. Use this state as the transportation state of blade 1 and wait for loading and transportation.

[0082] In this embodiment, prior to injection molding, additional steps such as initial cutting, grinding, and sealing of the blade root can be performed. These are common techniques in the field and will not be elaborated upon. This embodiment focuses on the blade root, but those skilled in the art can also apply this method to other locations on the blade where pre-embedded bolts are required, which will not be detailed here.

[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0084] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for injection molding of pre-embedded bolt sleeves on the outer surface of a wind turbine blade, characterized in that, Includes the following steps: S1. Blade preparation: Use a setting gauge to mark the horizontal meter mark on the ground, set up the SS surface support fixture on the ground according to the horizontal meter mark, then place the blade on the SS surface support fixture with the PS surface facing up, and verify the blade placement position with another setting gauge. S2. Flange tooling preparation and end face sealing: The flange tooling includes the flange body and the flange bracket for fixing the flange body. The flange tooling is assembled at the blade root position, and the gap between the blade and the flange body in the flange tooling is sealed and connected using sealant. S3. Grinding and laying the bolt sleeve underlayer and continuous felt: Grind and clean the surface of the blade root and the flange body. Then lay the set number of underlayers on the blade surface from bottom to top. After the underlayers are laid, lay the continuous felt according to the data in the layup table. S4. Laying pre-embedded bolt sleeves, wedge blocks, and UD bars: Clean the flange hole of the flange body, place a sealing ring inside the flange hole, and set the bolt sleeve at the blade root position with the root of the bolt sleeve attached to the flange body. Use positioning bolts to fix the bolt sleeve based on the flange hole. After fixing, place the UD bar next to the bolt sleeve with it attached to the radial outer surface of the bolt sleeve, and lay a wedge block at the tip of the bolt sleeve. Fix the set number of bolt sleeves in sequence from the middle to both sides. S5. Lay the upper layer of the bolt sleeve: Lay another set number of upper layers of fabric from bottom to top. After the upper layers of fabric are laid, lay the continuous felt according to the data in the layer laying table. S6. Lay out the release liner and pour in the auxiliary materials: Cover the area where the upper layer of fabric is laid with the release liner; A composite flow guide net is laid on the surface of the release cloth; air extraction bags are set at the blade root, leading edge parting line and trailing edge parting line of the blade respectively, and the air extraction bags are connected to the external air extraction pipeline. Multiple glue injection lines are laid sequentially from the leading edge to the trailing edge of the blade, and each glue injection line extends along the chord of the blade. S7. Arrange the air extraction system: Use release cloth to wrap the spiral tube as an air extraction pipe, and set the air extraction pipes at the front edge and the rear edge respectively. S8. Vacuum Pressure Holding: Lay the primary sealing vacuum bag film on the surface of the blade from the blade root to the blade tip. Turn on the vacuum pump to evacuate the primary vacuum bag film. After the primary vacuum bag film is tightened and the vacuum pump reading is ≥83kPa, lay the secondary sealing vacuum bag film and place a guide net between the primary and secondary sealing vacuum bag films. Then, perform a secondary vacuum evacuation. When the vacuum degree reaches below 30mbar, start the pressure holding test. S9. Injection and Curing: After the pressure holding test is passed, the injection pipeline is vented. After the venting time is set, the glass fiber resin is injected. Before the injection is completed, the heater is turned on and the heating temperature is gradually increased to the set temperature to heat the glass fiber resin until the glass fiber resin is cured, thus completing the injection molding of the PS surface of the blade. S10. Film removal and blade flipping: After the heat curing is completed, the surface hardness of the heat-cured area of ​​the blade is tested every 1m. If the surface hardness is above 60HD, the blade is peeled off when the surface temperature is below 45℃. If the hardness of the heat-cured area is below 60HD, the area is reheated and cured until the hardness of the area meets the standard, and then the film is peeled off. After the film is removed, disconnect the flange body from the flange bracket, flip the blades so that the SS face is facing upwards, and the flange body flips synchronously with them; replace the SS face bracket fixture with the PS face bracket fixture, place the flipped blades on the PS face bracket fixture, and then reconnect and fix the flange body to the flange bracket. S11. Repeat steps S3 to S9 to complete the SS surface injection molding of the blade, and perform a film removal process on the injection molded SS surface. S12, Blade Root Cutting: Disconnect the flange body from the flange bracket, flip the blade so that the PS face is facing upwards, and the flange body flips synchronously with it; replace the PS face bracket fixture with the SS face bracket fixture, and place the flipped blade on the SS face bracket fixture, and then reconnect and fix the flange body to the flange bracket; after the blade is placed stably, remove the flange fixture as a whole.

2. The injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to claim 1, characterized in that: The flange body consists of a PS face flange and an SS face flange. The assembly of the flange fixture includes the following steps: First, connect the SS face flange to the flange bracket, and place the flange bracket with the SS face flange at the blade root position; then, overlap and snap the PS face flange onto the top of the SS face flange from top to bottom, and connect the PS face flange to the bracket; finally, use a connecting plate to connect the PS face flange and the SS face flange.

3. The injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to claim 1, characterized in that: In step S3, the lower fabric layers are arranged in a staggered manner from bottom to top, and the chordal stagger distance between any two adjacent lower fabric layers is 3-5mm.

4. The injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to claim 1, characterized in that: In step S6, the distance from the guide net to the flange body along the axial direction is 60-100mm; Along the chord direction, the distance from the guide net to the front parting line is 50-100mm; the distance from the guide net to the rear parting line is 50-100mm.

5. The injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to claim 1, characterized in that: In step S6, the pipe spacing between any two adjacent glue injection lines is 400mm, and each glue injection line is provided with at least one glue injection port.

6. The injection molding method for pre-embedded bolt sleeves on the outer surface area of ​​a wind turbine blade according to claim 4, characterized in that: In step S6, the glue injection pipeline is set to three lines, namely pipeline I, pipeline II and pipeline III, which are laid sequentially from the leading edge to the trailing edge of the blade. Pipeline II is set at the highest point of the blade.

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