Electromagnetic flanging device and method capable of maintaining axial dynamic balance of coil

Abstract

The application discloses an electromagnetic flanging device and method capable of maintaining axial dynamic balance of a coil and belongs to the technical field of plastic processing of metal materials. The device comprises an upper die, a lower die, a forming sheet, a balance sheet, a driving coil and a pulse discharge circuit. The driving coil is symmetrically arranged between the two sheets, and the two sheets are consistent in material, shape and thickness. The central aperture of the upper die is slightly larger to allow flanging, and the central aperture of the lower die is slightly smaller to limit deformation. The method comprises the following steps: sequentially placing the balance sheet, the forming sheet and the die, and fastening and closing the switch to discharge. The pulse magnetic field makes the two sheets induce eddy currents and Lorentz forces which are equal in size and opposite in direction, so that axial dynamic balance of the coil is realized. The application solves the problem of instantaneous one-way stress of the coil, avoids high-speed impact, greatly improves the stability of shaft pressure shell and the service life of the device, and is beneficial to batch production.

Description

Technical Field

[0001] This invention relates to the field of metal material plastic processing technology, and in particular to an electromagnetic flanging device and method that can maintain the axial dynamic balance of a coil. Background Technology

[0002] Electromagnetic forming is a technique that uses pulsed electromagnetic force to shape metal materials, enabling deformation in an extremely short time. Its basic principle involves an electric current flowing through a discharge coil to generate a magnetic field. The surface of the sheet metal to be formed is subjected to strong induced eddy currents, with the current direction opposite to that of the discharge coil. This generates a repulsive Lorentz force between the sheet metal and the coil, causing the sheet metal to deform rapidly in an instant, and then continue to deform under the influence of inertial forces and a gradually weakening magnetic field. Compared to traditional stamping, electromagnetic forming's advantages of high quality, high precision, and high efficiency have expanded its applications, such as using pulsed electromagnetic force to achieve electromagnetic flanging and electromagnetic blanking. This technology is mainly used in aerospace, aviation, and vehicle manufacturing, particularly in large sheet metal parts such as aircraft skins.

[0003] The electromagnetic forming apparatus mainly consists of a discharge circuit system and a pulsed electromagnetic force generator. The discharge circuit system includes electronic components such as capacitors, resistors, inductors, and circuit switches. The pulsed electromagnetic force generator primarily uses a drive coil as its core component, comprising a multi-turn tightly wound copper spiral coil, an epoxy resin insulation layer, and a fiberglass axial pressure shell. As the core device of electromagnetic forming, the pulsed electromagnetic force generator releases enormous energy when the magnetic field reaches its peak, and a powerful Lorentz force acts on the coil. Improving the overall structural strength, reliability, and fatigue life of the generator is a pressing issue that needs to be addressed for the safe and stable operation of current electromagnetic forming technology.

[0004] Currently, existing optimization methods for pulsed electromagnetic force generators mainly fall into two categories. One is improving the thermal conductivity of the coil by optimizing the heat conduction path, such as connecting the external liquid nitrogen environment to the inner layer of the coil. The other is employing layered reinforcement techniques, such as wrapping with high-performance fiber composite materials. However, neither of these methods has achieved axial balance of the drive coil during the pulsed electromagnetic force release process; that is, the Lorentz force on the coil remains an instantaneous unidirectional force. Therefore, to fundamentally solve the fatigue failure problem of pulsed electromagnetic force generators without changing the overall structure of the drive coil, a new technical solution is needed. Summary of the Invention

[0005] The purpose of this invention is to provide an electromagnetic flanging device and method that can maintain the axial dynamic balance of the coil. By adding a balancing plate to the pulsed electromagnetic force generator, induced eddy currents of equal magnitude and opposite direction to those of the forming plate are generated in the balancing plate during the electromagnetic forming discharge process. Consequently, the balancing plate is subjected to a Lorentz force of equal magnitude and opposite direction to that of the forming plate. According to Newton's third law, the drive coil is subjected to two interaction forces in the axial direction from the forming plate and the balancing plate, and these forces are balanced. Simultaneously, because the lower mold restricts the deformation of the balancing plate, this pulsed electromagnetic force generator can be reused multiple times. The reinforcing layers of the drive coil, such as the fiberglass axial pressure shell, will be greatly protected from high-frequency, high-speed impacts. The pulsed electromagnetic force generator, while achieving flanging of the forming plate, significantly improves its service life and meets the requirements of simple tooling.

[0006] In a first aspect, the present invention provides an electromagnetic flanging device capable of maintaining the axial dynamic balance of a coil, comprising an upper die, a lower die, a forming sheet, a balancing sheet, a drive coil, and a pulse discharge circuit. The upper die and the lower die together form a fixture for fastening and positioning other components. The drive coil is located between the forming sheet and the balancing sheet, and the forming sheet and the balancing sheet are arranged symmetrically with respect to the axial center section of the drive coil as the center plane. The upper die allows the forming sheet to undergo flanging deformation during the forming process, while the lower die restricts the deformation of the balancing sheet during the forming process. The pulse discharge circuit is connected to the drive coil and is used to control the formation of a pulsed strong magnetic field.

[0007] Furthermore, the balance plate is made of the same material as the forming plate in terms of opening shape and thickness, so as to ensure that the magnitude of the induced eddy currents in both are consistent during the discharge process.

[0008] Furthermore, the drive coil is a helical coil with two terminals to ensure that the current forms a loop, wherein the outer helical terminal extends radially and the inner helical terminal extends axially.

[0009] Furthermore, an opening is provided at the center of the lower mold for the inner spiral terminal of the drive coil to pass through and be wired. The diameter of the opening is slightly smaller than the center diameter of the balance plate to limit the deformation of the plate.

[0010] Furthermore, the center hole diameter of the upper die is slightly larger than the center hole diameter of the forming sheet to achieve the flanging process of the forming sheet.

[0011] Furthermore, the upper and lower molds are made of hard alloy steel, which has poor electrical conductivity.

[0012] Furthermore, the inner helix diameter of the drive coil is not less than 40 mm, the coil pitch is between 2 and 5 mm, and the coil cross-sectional area is 20 to 40 mm². 2 .

[0013] Furthermore, the pulse discharge circuit includes an inductor, a resistor, a capacitor bank, and a circuit switch, which are connected in series to form a closed-loop circuit.

[0014] Furthermore, the drive coil is surrounded by a fiberglass board and an epoxy resin insulation layer.

[0015] Secondly, the present invention also provides an electromagnetic flanging method that can maintain the dynamic axial balance of the coil, comprising the following steps: S1. Place the balance plate material between the drive coil and the lower die, and adjust the position of the spiral terminal inside the drive coil so that it passes through the center hole of the balance plate material and the lower die. S2. Adjust the centerline position of the opening in the balance plate to make it coincide with the centerline of the drive coil, and tighten it with bolts to form an assembly; S3. Place the formed sheet above the assembly and adjust the center line position of the hole to be turned so that it coincides with the center line of the drive coil. S4. Place the upper mold on top of the forming sheet and adjust the center line of the mold hole to coincide with the center line of the hole to be turned on the forming sheet. Tighten the bolts to form a complete assembly. S5. When the pulse discharge circuit switch is closed, a pulse magnetic field is generated in the drive coil, and both the forming plate and the balance plate will induce eddy currents around the opening. Since the Lorentz forces on the two plates are equal in magnitude and opposite in direction, the drive coil will achieve force balance in the axial direction, thereby realizing electromagnetic flanging while ensuring the stability of the coil shaft pressing shell.

[0016] Therefore, the electromagnetic flanging device and method of the present invention, which adopts the above-described structure and can maintain the dynamic balance of the coil axial direction, has the following beneficial effects: (1) The service performance of the drive coil of the present invention is optimized. Since the Lorentz force on the drive coil during the discharge process is in axial dynamic equilibrium, the drive coil will not undergo high-speed impact motion, thereby avoiding fatigue failure of the drive coil under high-frequency discharge conditions.

[0017] (2) The service life of the electromagnetic flanging device of the present invention is improved. The epoxy resin wrapped around the outer surface of the drive coil will not be subjected to force. Furthermore, the fiberglass axial pressure shell around the pulse electromagnetic force generator will have sufficient strength to resist the high-speed impact from the drive coil, and the overall service life of the electromagnetic flanging device will be greatly improved.

[0018] (3) The electromagnetic flanging device and method of the present invention have simple tooling and low cost. Compared with the frequent replacement of discharge coils, this method can significantly improve economic benefits and is conducive to the mass production, mechanization and standardization of the process.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the initial state of the present invention; Figure 3 This is a cross-sectional view of the final state of the present invention; Figure 4 This is a schematic diagram of the discharge circuit system of the present invention; Figure Labels 1-Upper mold; 2-Forming sheet; 3-Drive coil; 4-Balance sheet; 5-Lower mold; 6-Outer spiral terminal of drive coil; 7-Inner spiral terminal of drive coil; 8-Fiberglass board; 9-Epoxy resin insulation layer; 10-Inductor; 11-Resistor; 12-Capacitor bank; 13-Circuit switch. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] Example like Figure 1-4 As shown, the present invention provides an electromagnetic flanging device that can maintain the dynamic balance of the coil axial direction, and includes an upper mold 1, a lower mold 5, a forming plate 2, a balancing plate 4, a driving coil 3, and a pulse discharge circuit.

[0024] The upper mold 1 and the lower mold 5 together form a fixture for fastening and positioning the pulse electromagnetic force generating device. The forming sheet 2 and the balancing sheet 4 are arranged symmetrically with the axial center section of the drive coil 3 as the center plane. The pulse discharge circuit is connected to the outer spiral terminal 6 of the drive coil and the inner spiral terminal 7 of the inner drive coil to control the formation of the pulsed strong magnetic field.

[0025] A cross-sectional view of the pulsed electromagnetic force generator is visible. Figure 2 , Figure 3 The outer periphery of the drive coil 3 includes a fiberglass board 8 and an epoxy resin insulation layer 9.

[0026] Specifically, the drive coil 3 is made of copper and has a multi-turn, tightly wound spiral structure to reduce resistance and improve conductivity. The epoxy resin insulation layer 9 tightly wraps around the coil for inter-turn insulation, while the outermost fiberglass board 8 serves as a high-strength axial pressure shell to provide radial support during discharge.

[0027] The inner helix diameter of drive coil 3 is not less than 40 mm, the coil pitch is between 2 and 5 mm, and the coil cross-sectional area is 20 to 40 mm². 2 .

[0028] Pulse discharge circuit visible Figure 4 Its components include an inductor 10, a resistor 11, a capacitor bank 12, and a loop switch 13 connected in series to form a closed-loop circuit.

[0029] The upper mold 1 and the lower mold 5 are made of hard alloy steel with poor electrical conductivity.

[0030] The present invention also provides an electromagnetic flanging method that can maintain the dynamic balance of the coil axial direction, applied to the above-mentioned device, specifically including the following steps: S1. Place the balance plate 4 between the drive coil 3 and the lower mold 5, and adjust the position of the spiral terminal 7 inside the drive coil so that it passes through the center hole of the balance plate 4 and the lower mold 5. S2. Adjust the centerline position of the opening of the balance plate 4 so that it coincides with the centerline of the drive coil 3, and fasten it with bolts to form an assembly; In step S2, it is particularly important to ensure the consistency of the material, opening shape, and thickness of the balancing plate 4 and the forming plate 2. This strict symmetrical configuration is to ensure that the magnitude and phase height of the eddy currents induced in the two plates are consistent at the moment of pulse discharge. If the material parameters are inconsistent, it will lead to an imbalance of forces, which will affect the stability of the drive coil 3. At the same time, the diameter of the center opening of the lower mold 5 is designed to be slightly smaller than the diameter of the center opening of the balancing plate 4. With the fastening effect of the bolts, a rigid support can be formed on the edge of the hole of the balancing plate 4 from a physical structure perspective, ensuring that it will not undergo flange deformation when subjected to downward Lorentz force.

[0031] S3. Place the formed sheet 2 on top of the assembly and adjust the center line position of the hole to be turned so that it coincides with the center line of the drive coil 3. S4. Place the upper mold 1 above the forming sheet 2, and adjust the center line position of the mold hole so that it coincides with the center line of the hole to be turned on the forming sheet 2. Use bolts to tighten and form a complete assembly. S5. When the pulse discharge circuit switch 13 is closed, a pulse magnetic field is formed in the drive coil 3, and the forming plate 2 and the balance plate 4 will both induce eddy currents around the opening. Since the Lorentz forces on the two plates are equal in magnitude and opposite in direction, the drive coil will achieve force balance in the axial direction, thereby realizing electromagnetic flanging while ensuring the stability of the coil shaft pressing shell.

[0032] In step S5, the Lorentz force on the forming sheet 2 drives it upward to flanging, while the Lorentz force on the balancing sheet 4 acts downward. Due to the effective constraint of the lower mold 5 on the balancing sheet 4, the balancing sheet 4 remains stationary, and its reaction force cancels out the thrust on the forming sheet 2 through the drive coil 3. This axial dynamic balancing mechanism prevents the drive coil 3 from experiencing severe axial movement or high-frequency vibration at the moment of discharge, unlike traditional single-sided electromagnetic forming, thus greatly reducing the mechanical impact on the fiberglass board 8 and the epoxy resin insulation layer 9, and effectively solving the problem of coil fatigue failure in the prior art.

[0033] The flanging process of the formed sheet 2 in this invention is as follows: Figures 2-3 As shown. The initial state 2-1 of the formed sheet 2 is as follows. Figure 2 As shown, at this time, the forming sheet 2 is tightly fitted with the drive coil shaft housing. When the circuit switch 13 in the discharge circuit is turned on, the forming sheet 2 is subjected to Lorentz force and undergoes flanging deformation in a very short time, its final state 2-2, as shown. Figure 3 As shown, the forming sheet 2 fits tightly against the inner opening of the upper mold 1, while the balancing sheet 4 remains unchanged compared to its initial state.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An electromagnetic flanging device capable of maintaining the dynamic axial balance of a coil, characterized in that, Includes upper mold, lower mold, forming sheet, balancing sheet, drive coil and pulse discharge circuit; The upper and lower molds together form a clamp for fastening and positioning other components; The driving coil is located between the forming plate and the balancing plate, and the forming plate and the balancing plate are arranged symmetrically with the axial center section of the driving coil as the center plane; The upper die is used to allow the forming sheet to undergo flanging deformation during the forming process, and the lower die is used to restrict the deformation of the balancing sheet during the forming process; The pulse discharge circuit is connected to the drive coil and is used to control the formation of a pulsed strong magnetic field.

2. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The balance plate material is the same material as the forming plate material in terms of opening shape and thickness.

3. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The drive coil is a helical coil with two terminals to ensure that the current forms a circuit, wherein the outer helical terminal extends radially and the inner helical terminal extends axially.

4. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 3, characterized in that, An opening is provided at the center of the lower mold. The opening is used for the inner spiral terminal of the drive coil to pass through the wiring, and the diameter of the opening is slightly smaller than the center diameter of the balance plate to limit the deformation of the balance plate.

5. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The center hole diameter of the upper mold is slightly larger than the center hole diameter of the forming sheet to realize the flanging process of the forming sheet.

6. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The upper and lower molds are made of hard alloy steel with poor electrical conductivity.

7. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The inner helix diameter of the drive coil is not less than 40mm, the coil pitch is between 2 and 5mm, and the coil cross-sectional area is 20 to 40mm². 2 .

8. The electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The pulse discharge circuit includes an inductor, a resistor, a capacitor bank, and a circuit switch, which are connected in series to form a closed-loop circuit.

9. An electromagnetic flanging device for maintaining the axial dynamic balance of a coil according to claim 1, characterized in that, The drive coil is surrounded by a fiberglass board and an epoxy resin insulation layer.

10. An electromagnetic flanging method for maintaining the axial dynamic balance of a coil, applied to an electromagnetic flanging device for maintaining the axial dynamic balance of a coil as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Place the balance plate material between the drive coil and the lower die, and adjust the position of the spiral terminal inside the drive coil so that it passes through the center hole of the balance plate material and the lower die. S2. Adjust the centerline position of the opening in the balance plate to make it coincide with the centerline of the drive coil, and tighten it with bolts to form an assembly; S3. Place the formed sheet above the assembly and adjust the center line position of the hole to be turned so that it coincides with the center line of the drive coil. S4. Place the upper mold on top of the forming sheet and adjust the center line of the mold hole to coincide with the center line of the hole to be turned on the forming sheet. Tighten the bolts to form a complete assembly. S5. Close the pulse discharge circuit switch to form a pulse magnetic field in the drive coil, so that the forming plate and the balance plate are induced to generate eddy currents around the opening. By utilizing the characteristic that the Lorentz forces on the two plates are equal in magnitude and opposite in direction, the drive coil achieves force balance in the axial direction, thereby ensuring the stability of the coil shaft pressing shell while realizing electromagnetic flanging.

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