Large slenderness ratio composite member bonding tooling to accommodate cure distortion and method of use

Abstract

The application belongs to the technical field of adhesive curing forming of helicopter composite components, and particularly relates to a large slenderness ratio composite component adhesive tooling suitable for curing deformation and a use method. A modular design structure form is adopted, a bottom frame is used as a main module to provide an installation platform, an upper module is designed on the installation platform, the upper module comprises a sliding table and a positioner and a clamping plate directly contacting the product, and the product is fixed on the sliding table after the positioner and the clamping plate are set. A bidirectional sliding platform is designed between the upper module and the main module to provide bidirectional sliding functions in the length direction and the width direction. When the main module is affected by temperature to generate size changes, the internal structure of the adhesive tooling can be self-adaptively adjusted to deform, and the upper module and the positioner will not slide, so that the generation of curing stress is avoided, and the deformation caused by the inconsistent thermal expansion coefficients is effectively controlled.

Description

Technical Field

[0001] This invention belongs to the field of adhesive bonding and curing molding technology for helicopter composite components, specifically relating to adhesive bonding tooling and application method for composite components with large aspect ratio that adapt to curing deformation. Background Technology

[0002] The helicopter horizontal stabilizer frame is made of composite material front beam, rear beam, and several ribs and reinforcing ribs bonded together. The overall length is about 4000mm and the width is about 1000mm. The structural dimensions have a large length-to-slenderness ratio. The bonding and curing process has many difficulties and requires special bonding tooling to position and clamp the composite parts. At the same time, the bonding tooling must be able to maintain accuracy when used under medium temperature conditions.

[0003] Traditional adhesive bonding fixtures are mostly made of ordinary carbon steel, with a rigid structure designed based on the positioning and clamping reference of composite parts. They are assembled through welding, machining, and assembly. During the adhesive curing process, the difference in thermal expansion coefficients can lead to stress generation and failure to release stress, resulting in product deformation and failure to meet precision requirements. Invar steel has a thermal expansion coefficient very close to that of composite materials, making it an excellent material for heat-curing fixtures. However, using only Invar steel for the fixtures would result in high manufacturing costs. Traditional adhesive bonding fixtures are typically vertical frames with casters, or frames equipped with forklift tubes, requiring manual or forklift-assisted transport, which is inefficient and inconvenient.

[0004] The helicopter vertical tail frame is made of composite material front beam, rear beam, reinforcing beam and several ribs bonded together. The overall length is about 4000mm and the width is about 600mm. The outer dimensions of the vertical tail frame bonding tooling are similar to those of the horizontal tail frame bonding tooling, and it needs to be heated and cured in a curing oven. Summary of the Invention

[0005] The main objective of this invention is to provide a bonding fixture and its application method that can be used under medium-temperature curing conditions and is adaptable to the curing deformation of composite components with large aspect ratios. The bonding fixture can avoid stress generation, thereby precisely controlling the molding dimensions and reducing technical quality problems. Through structural design, the manufacturing cost of the fixture is reduced, while simultaneously solving the problem of inconvenient fixture transportation. It also meets the requirement of simultaneous furnace loading with bonding fixtures for vertical tail skeletons of similar dimensions, improving production efficiency.

[0006] Technical solution: To achieve the above objectives, the present invention designs a bonding fixture for composite components with large aspect ratios that adapts to curing deformation. It adopts a modular design structure, with the bottom frame serving as a main module to provide an installation platform. An upper module is designed on the installation platform, which includes a slide table and a positioner and a clamping plate that directly contact the product. The positioner and clamping plate fix the product on the slide table.

[0007] Furthermore, the main module includes an installation platform and three legs. The installation platform is welded from square steel pipe profiles and steel plates. The upper surface is machined with accurate planes, threaded holes, and pin holes for installing slides and fixed supports. The lower surface is machined in the leg installation area to facilitate accurate installation of the legs.

[0008] Furthermore, the outriggers are welded from square steel pipe profiles and steel plates, and are fitted with fixed metal feet. The height of the outriggers is adjustable so that the tooling is in a horizontal position.

[0009] Furthermore, all tooling parts of the upper module are made of Invar steel, including a sliding frame, an upper clamping plate assembly, a lower clamping plate assembly, and a bidirectional slide rail. The sliding frame is machined from Invar steel plates after welding, providing a reference surface and reference holes. Slide rails are installed under the sliding frame, with a length slide rail installed at the front beam position and slide rails installed at the rear beam position in both the length and width directions. The length slide rail is installed at the same height as the front beam, and a width slide rail is installed below it.

[0010] Furthermore, upper and lower clamping plates are designed according to various positions of the product. The upper clamping plate provides the shape clamping function and is installed on the lower clamping plate. One end of the upper clamping plate is a pin and the other end is a pin for fixation. The lower clamping plate provides both shape positioning and positioner installation functions. The lower clamping plate is fixedly installed on the sliding frame with corner brackets.

[0011] Furthermore, the lower clamping plate assembly includes a lower clamping plate and beam locators and rib locators mounted on the lower clamping plate; used to provide accurate positioning of the part to be formed.

[0012] Furthermore, the upper clamping plate assembly includes an upper clamping plate and a handle, used to determine the shape of the upper surface of the part to be formed.

[0013] Furthermore, the installation platform also includes a fixed support, which fixes the midpoint of the upper sliding frame to the midpoint of the bottom frame to ensure that the tooling will not slip during transportation.

[0014] The above-designed adhesive bonding fixture for high aspect ratio composite components that adapts to curing deformation includes the following steps:

[0015] Step 1: Check the condition of the bonding fixture, count the parts of the bonding fixture, and confirm that it meets the usage requirements;

[0016] The second step is to open the upper clamping plate assembly of the adhesive bonding fixture in sequence, place the front beam, rear beam and each rib box part of the product on the lower clamping plate assembly, and use each positioning component to perform positioning and pre-assembly.

[0017] Step 3: Disassemble product parts as needed, install adhesive film, reposition, and lock parts using the included positioning bolts;

[0018] Step 4: Close the clamping plate assembly on the tooling in sequence to complete the clamping of all product parts on the tooling;

[0019] Step 5: The automatic transfer vehicle transports the flat tail skeleton bonding fixture into the curing oven, and the automatic transfer vehicle transports the vertical tail skeleton bonding fixture into the curing oven. The curing oven is then turned off, and the heating, heat preservation, and cooling programs are executed.

[0020] Step 6: Use an automatic transfer vehicle to transfer the flat tail skeleton bonding fixture and the vertical tail skeleton bonding fixture out of the curing oven respectively.

[0021] Step 7: Open the upper plate assembly, remove all positioning bolts, remove some positioners as needed, and remove the glued products from the shelf.

[0022] Step 8: Clean up the tooling and restore it to its initial state.

[0023] Technical effects: 1. The tooling material selected in this invention has a thermal expansion coefficient that is similar to that of the product material, which can effectively control product deformation and improve product quality;

[0024] 2. In the designed tooling structure, the upper locator (including beam and rib locators), clamping plate, and slide table are made of Invar steel, while the bottom frame is made of ordinary steel. Due to the significant difference in the coefficients of thermal expansion between ordinary carbon steel and Invar steel, dimensional changes between the upper module and the main module during heating and cooling can be dynamically compensated by the slide rail, effectively controlling the deformation caused by the inconsistency in thermal expansion coefficients. Specifically, a bidirectional sliding platform is designed between the upper module and the main module, providing bidirectional sliding functionality in both length and width directions. When the main module undergoes dimensional changes due to temperature, the internal structure of the adhesive bonding tooling can adaptively adjust the deformation without causing the upper module and locators to slide, thus avoiding the generation of curing stress.

[0025] 3. The front and rear beam positioners and each rib positioner are all installed on the lower clamping plate, which minimizes interference during the positioning of product parts on the shelf and the removal of parts after gluing, reduces the workload of tooling disassembly, and facilitates operation;

[0026] 4. The use of automated transfer vehicles for transfer before and after furnace loading makes it safer, more reliable, and more convenient;

[0027] 5. The tooling structure dimensions allow two sets of tooling to be placed in the furnace simultaneously, saving heating and curing time and resources. Attached Figure Description

[0028] Figure 1 Schematic diagram of the flat-tail frame bonding fixture structure;

[0029] Figure 2 A schematic diagram of the adhesive bonding fixture for the tailstock frame;

[0030] Figure 3 Schematic diagram of the dynamic compensation structure for the slide rail;

[0031] Figure 4 A schematic diagram showing two sets of fixtures being fed into the furnace simultaneously (flat-tail frame bonding fixture, vertical-tail frame bonding fixture).

[0032] Among them, 1—bottom frame; 2—fixed support; 3—bidirectional sliding platform; 4—sliding frame; 5—automatic transfer vehicle; 6—upper pallet assembly; 7—lower pallet assembly; 8—flat tail skeleton bonding clamp; 9—vertical tail skeleton bonding clamp; 10—curing oven; 11—length direction sliding track; 12—width direction sliding track. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0034] See appendix Figures 1-3 The adhesive bonding fixture structure specifically designed in this invention mainly includes: a bottom frame 1, a fixed support 2, a bidirectional sliding platform 3, a sliding frame 4, an automatic transfer vehicle 5, a lower clamping plate assembly 6, an upper clamping plate assembly 7, a length direction sliding track 11, and a width direction sliding track 12.

[0035] The bottom frame 1 serves as the foundation for the bonding fixture, providing an installation platform for other structures. It includes a platform and three legs arranged in a three-point configuration, providing access for the automated transfer cart 5. Adjustable feet at the bottom of each leg ensure the bonding fixture remains level. The lower surface of the fixed support 2 is connected to the bottom frame 1 with screws and pins, and the upper surface of the fixed support 2 is connected to the sliding frame 4 with screws and pins. The bidirectional sliding platform 3 consists of two sets of parallel longitudinal slide rails 11 and sliders, one set of width slide rails 12 and sliders, and a pad. One set of longitudinal slide rails 11 and sliders is mounted on the width slide rails 12 and sliders, while the other set is mounted on the pad. The width slide rails 12 and sliders are connected to the bottom frame 1 with screws and pins.

[0036] The lower plate assembly 6 is connected to the sliding frame 4 via a corner bracket. One end of the lower plate is a pin, and the other end is a pin structure for connecting with the upper plate assembly 7, so that the upper plate has the function of opening and closing along the pin.

[0037] The lower clamping plate assembly 6 includes a lower clamping plate and beam locators and rib locators mounted on the lower clamping plate; used to provide accurate positioning of the parts to be formed.

[0038] The upper clamping plate assembly 7 includes an upper clamping plate and a handle, used to determine the shape of the upper surface of the part to be formed.

[0039] The fixed support 2 fixes the midpoint of the upper sliding frame 4 to the midpoint of the bottom frame to ensure that the tooling will not slip during transportation.

[0040] In practical applications, the bonding process for composite components with a large slenderness ratio is as follows:

[0041] Step 1: Check the condition of the bonding fixture, count the parts of the bonding fixture, and confirm that it meets the usage requirements;

[0042] Step 2: Open the upper clamping plate assembly 6 of the adhesive bonding fixture in sequence, place the front beam, rear beam and each rib box part of the product on the lower clamping plate assembly 7, and use each positioning component to perform positioning and pre-assembly.

[0043] Step 3: Disassemble product parts as needed, install adhesive film, reposition, and lock parts using the provided positioning bolts;

[0044] Step 4: Close the clamping plate assembly 6 on the tooling in sequence to complete the clamping of all product parts on the tooling;

[0045] Step 5: Automatic transfer cart 5 transports the flat tail skeleton bonding clamp 8 into curing oven 10, and automatic transfer cart 5 transports the vertical tail skeleton bonding clamp 9 into curing oven 10. The curing oven is then turned off, and the heating, heat preservation, and cooling programs are executed.

[0046] Step 6: Use the automatic transfer vehicle 5 to transfer the flat tail skeleton bonding clamp 8 and the vertical tail skeleton bonding clamp 9 out of the curing oven 10 respectively.

[0047] Step 7: Open the upper plate assembly 6, remove all positioning bolts, remove some positioners as needed, and remove the glued products from the shelf.

[0048] Step 8: Clean up the tooling and restore it to its initial state.

[0049] To control curing deformation of products such as the WG-type machine's flat-tail frame and reduce tooling manufacturing costs, this invention features an innovative design for the bonding tooling. This includes selecting INVAR steel, a material with a coefficient of thermal expansion similar to that of the product, as a partial tooling material, and employing a special structural design to accommodate deformation caused by inconsistent coefficients of thermal expansion. For safe, reliable, and portable transport, the bonding tooling's legs are adaptively designed, allowing for transport using an automated transport vehicle. To improve efficiency, the bonding tooling is suitable for combination loading into the curing oven; its structure is designed according to the actual dimensions of the curing oven, ensuring that every two bonding fixtures can be combined for oven loading.

[0050] This invention achieves the use of mixed tooling materials and adapts to curing deformation through specific mechanical structure design. Moreover, the tooling structure meets the transportation requirements of automatic transfer vehicles. This structure facilitates transportation and is suitable for medium-temperature bonding and curing of composite components with large aspect ratios. This technology has been applied to the bonding of helicopter composite horizontal tail and vertical tail frames, promoting the upgrading of process technology, reducing manufacturing costs, improving production efficiency, and reducing quality problems.

[0051] The above specific embodiments or examples are only used to explain the technical solutions of the present invention and are not intended to limit the present invention. Parts not described in detail are considered as conventional technical means in the art. Those skilled in the art should understand that, based on the design concept of this application, it is possible to make adaptive modifications to the technical solutions described in the foregoing embodiments or to make equivalent substitutions for some or all of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A bonding fixture for composite components with a large aspect ratio that adapts to curing deformation, characterized in that, The system adopts a modular design structure. The bottom frame serves as the main module, providing an installation platform. An upper module is designed on this platform, including a slide table and locators and clamping plates that directly contact the product. The locators and clamping plates secure the product to the slide table. All tooling parts of the upper module are made of Invar steel, including a sliding frame, an upper clamping plate assembly, a lower clamping plate assembly, and bidirectional slide rails. The sliding frame is machined from Invar steel plates after welding, providing reference surfaces and reference holes. Slide rails are installed under the sliding frame. A length-direction slide rail is installed at the front beam position, and slide rails are installed in both the length and width directions at the rear beam position. The length-direction slide rail is installed at the same height as the front beam, and a width-direction slide rail is installed below it. Upper and lower clamping plates are designed according to various product positions. The upper clamping plate provides a shape clamping function and is mounted on the lower clamping plate, with one end secured by a pin and the other by a latch. The lower clamping plate simultaneously provides shape positioning and locator installation functions, and is fixed to the sliding frame using corner brackets.

2. The bonding fixture for composite components with large aspect ratios that adapts to curing deformation as described in claim 1, characterized in that, The main module includes an installation platform and three legs. The installation platform is welded from square steel pipe profiles and steel plates. The upper surface is machined with accurate planes, threaded holes, and pin holes for installing slides and fixed supports. The lower surface is machined in the leg installation area to facilitate accurate installation of the legs.

3. The bonding fixture for high aspect ratio composite components that adapts to curing deformation as described in claim 2, characterized in that, The outriggers are welded from square steel pipe profiles and steel plates, and are fixed metal feet with adjustable height to keep the tooling level.

4. The bonding fixture for high aspect ratio composite components that adapts to curing deformation as described in claim 1, characterized in that, The lower clamping plate assembly includes a lower clamping plate and beam locators and rib locators mounted on the lower clamping plate; used to provide accurate positioning of the parts to be formed.

5. The bonding fixture for composite components with large aspect ratios that adapts to curing deformation as described in claim 1, characterized in that, The upper clamping plate assembly includes an upper clamping plate and a handle, used to determine the shape of the upper surface of the part to be formed.

6. The bonding fixture for composite components with large aspect ratios that adapts to curing deformation as described in claim 1, characterized in that, The installation platform also includes a fixed support, which securely connects the midpoint of the sliding frame to the midpoint of the bottom frame to ensure that the tooling does not slip during transport.

7. The method of using the bonding fixture for composite components with large aspect ratios that adapts to curing deformation as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Check the condition of the bonding fixture, count the parts of the bonding fixture, and confirm that it meets the usage requirements; The second step is to open the upper clamping plate assembly of the adhesive bonding fixture in sequence, place the front beam, rear beam and each rib box part of the product on the lower clamping plate assembly, and use each positioning component to perform positioning and pre-assembly. Step 3: Disassemble product parts as needed, install adhesive film, reposition, and lock parts using the included positioning bolts; Step 4: Close the clamping plate assembly on the tooling in sequence to complete the clamping of all product parts on the tooling; Step 5: The automatic transfer vehicle transports the flat tail skeleton bonding fixture into the curing oven, and the automatic transfer vehicle transports the vertical tail skeleton bonding fixture into the curing oven. The curing oven is then turned off, and the heating, heat preservation, and cooling programs are executed. Step 6: Use an automatic transfer vehicle to transfer the flat tail skeleton bonding fixture and the vertical tail skeleton bonding fixture out of the curing oven respectively. Step 7: Open the upper plate assembly, remove all positioning bolts, remove some positioners as needed, and remove the glued products from the shelf. Step 8: Clean up the tooling and restore it to its initial state.

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