A replaceable power cord electric heating anti-icing blade forming junction box sealing method

Abstract

This invention relates to a sealing method for a replaceable power cord, electrically heated, anti-icing blade molded junction box, belonging to the field of mechanical structure design. This method protects the heating terminals and inner wall by sealing the junction box and other connecting holes, and by coating the inner surface with a sealing, solvent-resistant protective liquid and filling it with a powder substance that does not cure with adhesive and has anti-stick properties. This method reduces product scrap rates and lowers operating costs.

Description

Technical Field

[0001] This invention relates to a sealing method for a junction box with replaceable power cord, electric heating, and anti-icing blades, belonging to the field of mechanical structure design. Background Technology

[0002] An icing wind tunnel is a large, complex, specialized wind tunnel designed to ensure flight safety under icing conditions, enhance the operational capabilities of modern military aircraft in adverse weather conditions, and provide essential testing equipment for civil and general aviation aircraft to complete icing airworthiness certification and obtain necessary documentation. It is an indispensable ground testing facility for new aircraft development, particularly for large transport aircraft. With the development of my country's aviation industry, multi-functional icing wind tunnels have been developed. However, problems have arisen during use, such as fan blade icing and severe vibrations in the rotor system, affecting the normal operation of the wind tunnel. To address this, an electric heating anti-icing function has been added while maintaining the original blade performance requirements. Previously, the electric heating element was fixed to the blade surface by adhesive bonding. This structure is prone to detachment in alternating hot and cold environments and humid conditions, and insulation protection is difficult. A new structure is now being developed that integrates the electric heating element inside the blade. (See...) Figure 1 The blade's interior and exterior form a connected conduit. Because a replaceable power cord is required, heating terminals and temperature measuring power cords need to be pre-installed inside the junction box before curing. The junction box connects to the blade's interior in multiple places. During molding, adhesive enters the junction box, and the heating element's terminals and adhesive solidify together, making wiring impossible after curing. To solve this problem, a method for sealing the junction box during blade molding with a replaceable power cord and electric heating for anti-icing is adopted. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem that the electrically heated terminals and adhesive are cured together during blade forming, making it impossible to connect the wires after curing. This invention provides a sealing method for the junction box of the blade forming process, which uses a replaceable power cord and is electrically heated to prevent icing.

[0004] The technical solution of the present invention: a sealing method for a junction box with replaceable power cord, electric heating, and anti-icing blades, the method comprising the following steps:

[0005] 1) An electric heating element is wrapped around the leading edge of the blade. The terminal 6 of the electric heating element is located inside the blade, near the root. There is a square groove at the root of the blade. A junction box 5 made of insulating material is placed in the square groove. The junction box 5 has a groove on the side near the metal embedded part 2.

[0006] 2) The metal embedded part 2 is located at the root of the blade. Part of the metal embedded part 2 is located inside the root of the blade, and part of the metal embedded part 2 is located outside the root of the blade. The metal embedded part 2 is used to connect the blade to the hub of the wind tunnel compressor and the carbon fiber blade body. A through hole is opened inside the metal embedded part 2, and a groove is provided near the junction box 5 to communicate with the through hole. The through hole and the groove are connected to the inside of the blade.

[0007] 3) The copper tube 4 is a curved tubular structure. The copper tube 4 is fixedly installed inside the blade, and both ends of the copper tube 4 are facing the root of the blade. The copper tube 4 connects the inside of the junction box 5 with the through hole of the metal embedded part 2.

[0008] 4) Make foam 7. The shape of foam 7 is the same as the groove on the side of junction box 5. Foam 7 is embedded in the groove of junction box 5, and an annular groove is made on foam 7. Insert one end of copper tube 4 into the annular groove.

[0009] 5) Make foam 2 8 and place it between foam 1 7 and the inner wall of junction box 5 to prevent foam 1 7 from falling out of the groove on the side of junction box 5.

[0010] 6) Junction box 5 has an opening on the bottom surface. A plug 9 is machined, and the shape of the plug is larger than the shape of the opening on the bottom surface of the junction box. The plug 9 is used to seal the opening on the bottom surface of junction box 5. A layer of release cloth is attached to the opening on the bottom surface of junction box 5 and the outside of the plug 9, and then heated and cured.

[0011] The plug 9 has elastic, closed-cell, and high-temperature resistant properties.

[0012] The plug material is EPDM.

[0013] The junction box 5 is filled with talc powder 10, which has adhesive properties and does not cure with adhesive.

[0014] Foam 1-7 and Foam 2-8 are PMI foams, which are closed-cell foams with the highest specific stiffness and specific strength.

[0015] Apply a protective liquid to the inner surface of junction box 5 and the inner wall of copper pipe to prevent the adhesive from solidifying on the inner surface of junction box 5 and the inner wall of copper pipe.

[0016] A layer of protective liquid, silicone grease, is applied to the inner surface of junction box 5 and the inner wall of copper pipe, providing sealing and solvent resistance. Attached Figure Description

[0017] Figure 1 Blade cross-section

[0018] Figure 2 Optimized blade structure diagram

[0019] Figure 3 Enlarged view at point K

[0020] Figure 4 Bubble One

[0021] Among them: 1 is PMI foam, 2 is metal embedded part, 3 is carbon fiber, 4 is copper pipe, 5 is junction box, 6 is electric heating element wiring terminal, 7 is foam one, 8 is foam two, 9 is plug, and 10 is talcum powder. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings.

[0023] Depend on Figure 2 As can be seen, to achieve a sealing method for a junction box with replaceable power cord, electric heating, and anti-icing blades, it is necessary to seal the holes around the junction box 5 to prevent adhesive from entering the interior of the junction box 5. The steps are as follows:

[0024] 1. Apply a layer of silicone grease inside the junction box 5 and the copper pipe 4 to protect the inner walls and prevent the adhesive from solidifying on the surface. To prevent the adhesive from entering the copper pipe 4, insert the copper pipe 4... Figure 4 As shown, foam 7, copper tube 4, and foam 7 form a closed space, preventing the adhesive from entering.

[0025] 2. Junction box 5 has a slot on the side. Place the assembly assembled in step 1 into the slot on the side of junction box 5. After filling the bottom of junction box 5 with some talcum powder 10, place foam 2 8 between foam 1 7 and the inner wall of junction box 5 to prevent the foam on copper tube 4 from falling off due to the internal pressure when the blade is cured.

[0026] 3. Place the electric heating element terminal 6 inside the box 2, and then fill it with talcum powder 10 to protect the electric heating element terminal 6. Place a plug 9 made of EPDM and larger than the inner cavity of the junction box 5 into the opening on the bottom surface of the sealed junction box 5. Apply a layer of release cloth to the opening on the bottom surface of the junction box 5 and the outside of the plug 9, and heat it to cure.

Claims

1. A sealing method for a junction box with replaceable power cord, electric heating, and anti-icing blades, characterized in that... The method comprises the following steps: 1) An electric heating element is wrapped around the leading edge of the blade. The electric heating element terminal (6) is located inside the blade, near the root. There is a square groove at the root of the blade. A junction box (5) made of insulating material is placed in the square groove. The junction box (5) has a groove on the side near the metal embedded part (2). 2) The metal embedded part (2) is located at the root of the blade. Part of the metal embedded part (2) is located inside the root of the blade and part of the metal embedded part (2) is located outside the root of the blade. The metal embedded part (2) is used to connect the blade to the hub of the wind tunnel compressor and the carbon fiber blade body. A through hole is opened inside the metal embedded part (2), and a groove is provided near the junction box to communicate with the through hole. The through hole and the groove are connected to the inside of the blade. 3) The copper tube (4) is a curved tubular structure. The copper tube (4) is fixedly installed inside the blade, and both ends of the copper tube (4) are facing the root of the blade. The copper tube (4) connects the inside of the junction box (5) with the through hole of the metal embedded part (2). 4) Make foam one (7). The shape of foam one is the same as the shape of the groove opened on the side of the junction box (5). Foam one (7) is embedded in the groove of the junction box (5), and an annular groove is opened on foam one. One end of copper tube (4) is inserted into the annular groove. 5) Make foam 2 (8), place foam 2 (8) between foam 1 (7) and the inner wall of junction box (5) to prevent foam 1 (7) from falling out of the groove on the side of junction box; 6) The bottom surface of the junction box (5) has an opening. A plug (9) is processed. The shape of the plug is larger than the shape of the opening on the bottom surface of the junction box. The plug (9) is used to seal the opening on the bottom surface of the junction box. A layer of release cloth is attached to the opening on the bottom surface of the junction box and the outside of the plug (9), and then heated to cure.

2. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 1, characterized in that, The junction box (5) is filled with talc powder (10), which has adhesive properties and does not cure with adhesive.

3. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 1, is characterized in that... The plug (9) is made of a material that is elastic, closed-cell, and resistant to high temperatures.

4. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 3, is characterized in that... The plug (9) is made of EPDM material.

5. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 1, characterized in that, The foam one (7) and foam two (8) are made of PMI foam, which has closed-cell characteristics and the highest specific stiffness and specific strength among foams.

6. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 1, characterized in that, Apply a protective liquid to the inner surface of the junction box (5) and the inner wall of the copper pipe to prevent the adhesive from solidifying on the inner surface of the junction box (5) or the inner wall of the copper pipe.

7. The sealing method for the junction box of the replaceable power cord, electrically heated anti-icing blade as described in claim 6, characterized in that, Apply a layer of silicone grease as a protective liquid to the inner surface of the junction box (5) and the inner wall of the copper tube. It has sealing and solvent resistance properties.

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