CN110681760B - An electromagnetic pulse turning hole forming device for thick plate parts or thick arc parts - Google Patents

Abstract

The invention belongs to the field of plastic forming of materials, and discloses an electromagnetic pulse hole flanging forming device for a thick plate part or a thick arc-shaped part, wherein the forming device for the thick plate part comprises a coil and a magnetic collector (103) positioned on one side of the coil, and the magnetic collector (103) is disc-shaped and is provided with two disc surfaces with different surface areas; recording a surface A with a larger surface area and a surface B with a smaller surface area, wherein the surface A is closer to the coil, and the surface B is used for being closer to a workpiece to be formed; the area difference is utilized to generate larger current density at one end of the magnetic collector (103) close to the surface B, so that the workpiece to be formed is subjected to larger electromagnetic force, and the electromagnetic pulse hole flanging forming is facilitated. According to the invention, through improving the overall structure design and the like of the device, the magnetic collectors are additionally arranged between the coils and the plate, and the multi-layer coils are matched, especially through the design of the A surfaces and the B surfaces of the magnetic collectors with surface area difference, the electromagnetic force is concentrated in the forming area corresponding to the B surface of the magnetic collector, and a good forming effect can be achieved.

Description

An electromagnetic pulse turning hole forming device for thick plate parts or thick arc parts

technical field

The invention belongs to the technical field of material plastic forming, and more particularly, relates to an electromagnetic pulse turning hole forming device for thick plate parts or thick arc parts. The coil solves the problem that the current electromagnetic forming coil cannot withstand high-voltage and high-energy discharge conditions, and makes the application of electromagnetic forming in thick plate turning more mature.

Background technique

In order to meet the needs of lightweight structures and materials, reduce energy consumption and environmental pollution, aluminum alloys with lower density and higher specific strength are increasingly used in the automotive and aerospace fields. However, aluminum alloys have problems such as low forming limit and serious springback, which seriously restrict the development of aluminum alloys. Electromagnetic forming is a forming and processing method that uses Lorentz force to cause high-speed plastic deformation of metal materials. This method can improve the forming limit of the material and effectively reduce the springback. The formed workpiece has a small residual stress, and the workpiece has a relatively High surface quality, has broad prospects in forming aluminum alloys. In addition, the electromagnetic forming tooling is simple, no large platform is required for positioning, and the forming coil and the die only need to be fixed in the forming area, and the adjustment of the coil position is also more flexible.

In the aerospace field, many large-shaped parts need to be formed. When using traditional processes, higher requirements are placed on tooling platforms, molds and equipment; and some parts need to be formed with local features to achieve specific functions, which is extremely difficult. Compared with traditional methods, electromagnetic forming has great advantages in the aerospace field. It can not only improve production efficiency, obtain workpieces with higher precision and better quality, but also use the flexibility of coil manufacturing to form local features.

Electromagnetic forming is to pass a pulse current to the coil. Under the action of electromagnetic induction, a certain depth of instantaneous current will also be generated on the sheet. The magnetic field generated by the current on the sheet and the magnetic field generated by the current in the coil repel each other. When When the repulsive force exceeds the yield strength of the material, the sheet will deform. The depth of the current formed on the sheet becomes the skin depth, and this area is the area where the electromagnetic body force acts. Skin depth is related to material resistivity, material permeability, and discharge frequency.

In formula (1), d: skin depth; ρ: resistivity; μ: permeability; f: discharge frequency.

During the electromagnetic forming process, the sheet material quickly obtains a high speed of motion in a short period of time, and most of the plastic deformation is caused by the inertial effect under high-speed motion. Nowadays, good results can be achieved when using electromagnetic forming for sheet flanging. The thickness of the sheet increases and the forming difficulty increases. The main reason is that the non-electromagnetic body force action area increases, the relative proportion of the body force action area decreases, and the electromagnetic body force effect is weakened. In the case of increasing sheet thickness, in order to achieve the desired forming effect, it is necessary to increase the skin depth in the electromagnetic forming process. It can be seen from formula (1) that, when the material remains unchanged, increasing the skin depth requires reducing the discharge frequency. It can be seen from equation (2) that the control inductance remains unchanged, and increasing the capacitance can reduce the discharge frequency, but it will lead to a sharp increase in the discharge energy, and the coil will have to bear more energy and reaction force during the discharge process.

In formula (2), f: discharge frequency; c: capacitance; l: inductance.

Due to the limitation of the manufacturing process, when the coils currently used are discharged at high energy, under the combined action of force and heat, the epoxy resin fails, resulting in a sharp decrease in the strength of the coil structure, and a short circuit occurs when the wires are squeezed against each other, often after a discharge. , the coil cannot be used again. There are two ways to solve this problem: one is to use a material with better performance instead of copper wire to wind the coil; the other is to optimize the structural design of the coil and improve the strength of the coil. Before the new ideal material comes out, more research on the structure is carried out.

The cross-sectional shape of the forming coil used in electromagnetic forming is circular or rectangular. Research shows that the cross-sectional area of the forming coil seriously affects the forming ability and service life of the coil. When the cross-sectional area of the coil is small, the electromagnetic force generated by the coil can be better concentrated in the forming area, and the forming effect is good. short. Especially for the electromagnetic pulse punching forming of thick plates (such as plates with a thickness of 7-8 mm, etc.), due to the large thickness of the plate, a large voltage is required during forming, and the coil is subjected to a large impact load during the forming process. , the coil is easily damaged; if a coil with a larger turn spacing is used, the strength of the coil structure is greatly improved, but the electromagnetic force will not be concentrated, and the ideal forming effect cannot be achieved.

In order to make the projected area of the coil correspond to the sheet forming area to ensure a good distribution of the electromagnetic force, when forming in a small area, most of the existing processes adopt the form of close winding, that is, the turn spacing is small. When the thickness of the sheet is small , low-voltage discharge can ensure the service life of the coil; when the thickness of the sheet increases to a certain amount, due to the increase of the required forming force, a larger discharge energy is required, and the coil is very easy to fail under the combined effect of force and heat. , even after one discharge, the coil needs to be replaced with a new coil, resulting in an increase in the cost of the coil and a longer product manufacturing cycle.

SUMMARY OF THE INVENTION

In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide an electromagnetic pulse punching forming device for thick plate parts or thick arc parts. By improving the overall structural design of the device, etc. A magnetic collector is added between the sheet and the multi-layer coil, especially through the design of the A and B surfaces of the magnetic collector with surface area differences (where the surface area of the A surface is larger, and the surface area of the B surface is smaller), so that the surface near the B surface is designed. The induced current density is larger than that near the A surface, and the electromagnetic force near the B surface is also larger, so that the electromagnetic force is concentrated in the forming area corresponding to the B surface of the magnetic collector, and a good forming effect can be achieved. The invention solves the problem that the current electromagnetic forming coil cannot withstand high-voltage and high-energy discharge conditions, and makes the application of electromagnetic forming in the turning of thick plate parts more mature. Moreover, based on the present invention, the used coil can not only withstand a large voltage, but also can ensure the forming effect of discharge forming on a small area. By setting a magnetic collector with a specific surface area shape to match the coil, the turn spacing of the coil can be kept large. The unique turn spacing design not only improves the strength of the coil and ensures the service life of the coil, but also makes the electromagnetic force concentrated in the forming area to achieve a better forming effect.

In order to achieve the above object, according to an aspect of the present invention, an electromagnetic pulse punching forming device for thick plate parts is provided, which is characterized in that it comprises a coil and a magnetic collector (103) located on one side of the coil, wherein the The magnetic collector (103) is in the shape of a disk, and has two upper and lower flat disk surfaces with different surface areas. The side slit is communicated with the through hole so that the collector regions on both sides of the slit are completely isolated by the slit;

The coil is a single-layer coil or a multi-layer coil; when the coil is a single-layer coil, the single-layer coil is distributed inside and outside the same plane by a metal wire (101) around the central axis of the disk, and the plane is parallel to the plane. The upper and lower surfaces of the magnetic collector (103); when the coil is a multi-layer coil, any layer of coils in the multi-layer coil is made of metal wires (101) around the central axis of the disk and is distributed inside and outside the same plane. The planes where the layer coils are located are parallel to the upper and lower surfaces of the magnetic collector (103);

Denote the surface with a larger surface area of the magnetic collector (103) as the A surface, and the surface with a smaller surface area as the B surface, then the A surface is closer to the coil than the B surface, and the B surface is used for It is close to the workpiece to be formed, and the coil and the magnetic collector (103) are connected and integrated through an insulating resin; when an alternating current is applied to the coil, the induced current generated by the coil on the A side will pass through the narrow The slit flows to the B surface. Using the area difference between the A surface and the B surface, a larger current density will be generated at the end of the magnetic collector (103) close to the B surface, so that the workpiece to be formed is subjected to a larger electromagnetic force, thereby facilitating the electromagnetic pulse. Flip hole forming.

As a further preference of the present invention, the cross-sectional shape of the metal wire (101) is rectangular, and the inter-turn spacing is between 2 mm and 5 mm; when the coil is a multilayer coil, the inter-layer spacing is between 2 mm and 4 mm.

As a further preference of the present invention, the coil is a three-layer coil; the metal wire (101) is a red copper wire.

As a further preference of the present invention, a bolt hole is also provided in the winding center of the multi-layer coil, and one end of the bolt hole is communicated with the through hole in the center of the disk of the magnetic collector (103); Fastening bolts are used to strengthen the strength of the overall structure after the coil and the magnetic collector (103) are integrated; and the surfaces of the fastening bolts are also subjected to insulation treatment.

As a further preference of the present invention, the magnetic collector (103) adopts chromium zirconium copper.

As a further preference of the present invention, the thickness of the magnetic collector (103) is twice the skin depth.

As a further preference of the present invention, the ratio of the diameters of the A side to the B side is not more than 2, preferably equal to 2.

As a further preference of the present invention, the insulating resin is epoxy resin (105).

As a further preference of the present invention, the workpiece to be formed is a sheet material to be formed; preferably, the sheet material to be formed is a thick aluminum alloy sheet material to be formed with a thickness of 7-8 mm.

According to one aspect of the present invention, there is provided an electromagnetic pulse drilling forming device for thick arc-shaped parts, which is characterized by comprising a coil and a magnetic collector (103) located on one side of the coil, wherein the magnetic collector (103) 103) is disc-shaped, and has two upper and lower disc surfaces with different surface areas, wherein the surface with a larger surface area is in a plane shape, and the surface with a smaller surface area is in an arc shape; the disk of the magnetic collector (103) A through hole is opened in the center, and the slit located on one side of the central axis of the disc is communicated with the through hole, so that the magnetic collector areas on both sides of the slit are completely isolated by the slit;

The coil is a single-layer coil or a multi-layer coil; when the coil is a single-layer coil, the single-layer coil is distributed inside and outside the same plane by a metal wire (101) around the central axis of the disk, and the plane is parallel to the plane. A surface with a larger surface area in the magnetic collector (103); when the coil is a multi-layer coil, any layer of coils in the multi-layer coil is made of metal wires (101) around the central axis of the disk and is distributed inside and outside the same plane. , the plane where each layer of coils is located is parallel to the surface with a larger surface area in the magnetic collector (103);

Denote the surface with a larger surface area of the magnetic collector (103) as the A surface, and the surface with a smaller surface area as the B surface, then the A surface is closer to the coil than the B surface, and the B surface is used for It is close to the workpiece to be formed, and the coil and the magnetic collector (103) are connected and integrated through an insulating resin; when an alternating current is applied to the coil, the induced current generated by the coil on the A side will pass through the narrow The slit flows to the B surface. Using the area difference between the A surface and the B surface, a larger current density will be generated at the end of the magnetic collector (103) close to the B surface, so that the workpiece to be formed is subjected to a larger electromagnetic force, thereby facilitating the electromagnetic pulse. Flip hole forming.

Through the above technical solutions conceived by the present invention, taking the electromagnetic pulse punching forming device for thick plate parts as an example, compared with the prior art, the following beneficial effects can be obtained:

1) The present invention realizes the formation of small areas by large coils by adding a magnetic collector with a difference in the surface area of the upper and lower discs between the coil and the sheet, and is especially suitable for thick plates (such as aluminum alloys with a thickness of 7-8 mm). The electromagnetic pulse turning hole forming device for thick plate parts) can overcome the disadvantage of insufficient forming force. The A-side of the collector (ie, the surface with the larger surface area) is near the coil, and the B-side (ie, the surface with the smaller surface area) is near the work to be formed (eg, the sheet to be formed). The induced current generated by the coil on the magnetic collector is concentrated on the B side, and at the same time, the induced current is generated in the sheet forming area to achieve the purpose of electromagnetic force concentration. Moreover, compared with the problems of difficult processing, high cost and short life of the coil, the regional distribution of the electromagnetic force can be changed by further replacing the magnetic collectors of different shapes (upper and lower surface area, thickness), so as to realize the deformation of different forming areas, which is simpler, convenient. In the present invention, the thickness of the magnetic concentrator is preferably twice the skin depth, which can effectively avoid the reverse cancellation of the currents on the A side and the B side. In the present invention, the larger the ratio of the surface area of the A surface and the B surface of the magnetic concentrator, it means that the energy is concentrated in a smaller area, so that the area can obtain a larger magnetic field strength and electromagnetic force, which is more conducive to forming. In the present invention, the ratio of the surface area of the A surface and the B surface of the magnetic collector is preferably not more than 4 (the surface area of the A surface is greater than the surface area of the B surface), that is, the ratio of the diameter of the A surface to the B surface does not exceed 2, and the A surface of the magnetic collector is not more than 2. The ratio of the diameter of the surface and the surface B is called the relative diameter of the magnetic collector. The maximum value of the electromagnetic force increases with the increase of the relative diameter, but the degree of increase becomes smaller and smaller. Generally, after the relative diameter reaches 2, the increase of the electromagnetic force increases. Very slowly, the ratio of the diameters (ie relative diameters) of the A side to the B side of the present invention is preferably equal to 2.

2) The present invention optimizes the coil structure, especially multi-layer coils can be used, which not only ensures high strength, but also can withstand the huge reaction force during forming (the more layers of coils, the greater the forming force can be provided), It can cooperate with the magnetic collector assembly to further increase the magnitude of the electromagnetic forming force, and meet the demand for the magnitude of the electromagnetic force when the thick plate is formed. The present invention preferably adopts a multi-layer coil, which can also obtain a good molding effect when the thick plate material is turned through.

3) Based on the present invention, the used coil can not only withstand a large voltage, but also ensure the forming effect of discharge forming on a small area. While ensuring the ideal forming effect, it also ensures the service life of the coil, reduces costs, and shortens manufacturing cycle. In the traditional coil design, in order to ensure the forming effect, the projected area of the coil corresponds to the sheet forming area. When forming in a small area, in order to achieve the huge force required for forming a large plate thickness, the coil can only be densely wound with multiple turns. , there will be a strong interaction force between turns and turns, and the current density per unit area is very large. The thermal effect of the current makes the temperature rise of the coil very large during discharge, and even carbonizes the epoxy resin. Contact short-circuit, resulting in coil damage. Due to the existence of the magnetic collector, the invention can utilize the further design of the surface of the magnetic collector to realize the matching between the B surface of the magnetic collector and the small area to be formed, avoid the arrangement of multiple turns of the coil densely wound, optimize the coil structure, and have a higher structure. The strength is improved, the service life of the coil is improved, and the problem of high cost caused by the current coil damage is overcome.

The present invention can use red copper wire to wind the coil structure, and the turn spacing is preferably controlled to be between 2mm and 5mm. In addition to the turn spacing, the present invention also controls the cross-sectional shape of the coil structure to be a rectangle. The coil makes the deformation of the sheet more uniform. In addition, when the multilayer coil is used, the present invention also preferably controls the layer spacing of the multilayer coil structure to be 2mm to 4mm; if the layer spacing is too small, it will lead to the concentration of the wires, due to the thermal effect of the current and the mutual repulsion between the wires. , the heat and force generated when energized will also be relatively concentrated, which will affect the structural strength and service life of the coil, and the increase in the spacing will weaken the effect of electromagnetic force; therefore, selecting the appropriate layer spacing can not only ensure the coil Sufficient structural strength can also ensure that sufficient electromagnetic force is provided during the forming process.

The magnetic collector in the present invention plays the role of concentrating the electromagnetic force in the small forming area through the difference of the upper and lower areas, and the coil can adopt a coil with a larger turn spacing; The turn spacing of the coil reduces the peak value of the electromagnetic force; and the present invention can avoid this unfavorable phenomenon by using the cooperation of the multi-layer coil and the magnetic collector (the feasibility of the method is also verified through the subsequent finite element numerical simulation). The present invention can preferably use three-layer coils, and each layer of coils is preferably wound with a larger turn spacing (the turn spacing is preferably between 2 mm and 5 mm). When the power is lowered, there is enough space for the heat to diffuse; on the other hand, the space between the wires is filled with epoxy resin of sufficient thickness, so as to restrain the mutual extrusion of the wires and ensure that they can eventually withstand high-energy multiple discharges , prolong the service life of the coil, reduce the loss of the coil, make the coil reusable, and effectively reduce the cost.

The above analysis is based on the electromagnetic pulse punching and forming device for thick plate parts (the magnetic collector used has upper and lower two flat disc surfaces) as an example, when the workpiece to be formed is an arc-shaped part, especially a thick plate. In the case of arc-shaped parts, the lower surface of the magnetic collector with a smaller area can be designed to be a curved surface (ie, arc-shaped) consistent with the surface characteristics of the sheet metal, and correspondingly, an electromagnetic pulse turning hole forming device for thick arc-shaped parts can be obtained; Other structures (such as coils, etc.) in the electromagnetic pulse turning-hole forming device for thick arc-shaped parts can be configured similarly to the electromagnetic pulse turning-hole forming device for thick plate parts, and similar beneficial effects are obtained.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the magnetic collector in the electromagnetic pulse turning and forming device for thick plate parts.

FIG. 2 is a schematic diagram of the relative positions of the coil and the magnetic collector in the electromagnetic pulse punching and forming device for thick plate parts.

FIG. 3 is a schematic diagram of the coil in the electromagnetic pulse punching and forming device for thick plate parts.

Fig. 4 is a schematic diagram of the relative positions of the various components in the electromagnetic pulse punching and forming device for thick plate parts.

FIG. 5 is a schematic diagram of the tooling of the electromagnetic pulse punching and forming device for thick plate parts.

Fig. 6 is the connection circuit diagram of the electromagnetic forming machine and the pulse discharge circuit.

Fig. 7 is a schematic view of the tooling of the electromagnetic pulse drilling and forming device for thick arc-shaped parts, wherein the magnetic collector part has an arc-shaped lower surface.

The meanings of the reference signs in the figure are as follows: 1 is the overall assembly formed by the coil and the magnetic collector, 2 is the blank holder, 3 is the sheet material, 4 is the mold, 5 is the switch, 6 is the resistor, 7 is the capacitor, and 101 is the Metal wires (corresponding to metal coils), 102 is a fastening bolt, 103 is a magnetic collector, 104 is a gasket, and 105 is an epoxy resin.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The forming device in the present invention, that is, the electromagnetic punching forming device, as shown in FIG. 5 , includes a pulse discharge circuit, a forming coil, a die, a blank holder and a blank. The coil system includes a three-layer flat spiral coil and a magnetic collector. The three-layer flat spiral coil is connected in series (that is, the coil is in the form of a longitudinal three-layer concentric coil, and the series connection can meet the force and energy requirements during forming), and the magnetic collector Below the flat coil, it is not in contact with the coil, and is separated by epoxy resin insulation (that is, the coil and the magnetic collector are integrated in one piece, and the gap between them is filled with epoxy resin).

The magnetic collector, as shown in Figure 1, is in the shape of a disk, and has two upper and lower disk surfaces with different surface areas. Communication with the through hole makes the collector regions on both sides of the slit completely isolated by the slit. The magnetic collector plays the role of concentrating the electromagnetic force to the small forming area through the difference between the upper and lower areas. The slit is filled with epoxy resin after processing, and the function of the collector slit is to make the induced current flow from the upper surface to the lower surface.

The coil may further include fastening bolts to further enhance the strength of the coil and improve the service life. That is to say, in order to ensure that the whole has high structural strength and can withstand the huge reaction force in the forming process, bolts can be added to the holes between the coil and the magnetic collector, and the surface of the bolts is insulated (for example, the bolts It can be wrapped with insulating paper to ensure good insulation with the coil and the collector).

Further, the bolts 102 and washers 104 shown in FIG. 3 are wrapped in epoxy resin, and the nut above is used to adjust the tightness.

As shown in Figure 5, the sheet material is placed above the die, the area to be formed on the sheet material is blanked, and then the forming coil is pressed on the blanking ring. During the actual experiment, a press can be used to apply pressure to the A surface of the coil (the A and B surfaces of the coil are based on the A and B surfaces of the magnetic collector, and the A surface of the coil - the B surface of the coil - the A surface of the magnetic collector - the magnetic collector. Named in the way that the B faces are arranged in sequence), the size of the pressure should meet the requirements of the blank holder force, and be sufficient to resist the reaction force of the sheet material to the coil during the forming process.

The coil 1 is connected to the switch 5, the protection resistor 6, and the energy storage capacitor 7 in sequence. The electromagnetic forming machine 9 is connected to the switch 5 , the protection resistor 6 and the energy storage capacitor 7 through the switch 8 at the other end. According to the energy required to form the workpiece, set the electrical parameters that meet the conditions. The present invention is suitable for turning holes in thick plates, and an electromagnetic forming machine capable of providing sufficient voltage and energy is required during use.

Close switches 8 and 5, and the electromagnetic forming machine charges the capacitor 7. After the charge is fully charged, the switch 8 is turned off, and the capacitor 7 discharges the coil 1.

Further, the pulsed current in the series-connected three-layer flat helical coil generates an induced current on the upper surface of the lower magnetic collector.

Further, the induced current generated by the coil at the large-area end of the magnetic collector will flow to the lower surface. Due to the area difference between the upper and lower surfaces, the current density on the lower surface of the magnetic collector is greater than that on the upper surface, which in turn generates a larger induced current on the sheet material, and electromagnetic repulsion. The force forms the sheet.

The coil is encapsulated with epoxy board. The experimental results show that after the coil is damaged, the wire in the central area breaks or even explodes under the combined action of the force. Therefore, the present invention preferably uses the fastening bolt 102 and the gasket 104 to constrain the wire in the central area, which plays a better role in tightening effect. The gaps between the parts in Figure 3 are filled with epoxy resin to ensure good insulation between the metal parts.

The example shown in the present invention is oblique hole flanging, and the forming of the side with the acute angle of the concave die is more difficult. In experiments and simulations, it is found that the electromagnetic force at the slit of the magnetic collector is small (as shown in Figure 1, the magnetic collector is in the There is a slit in the longitudinal direction), which belongs to the weak area. During tooling, the slit on the magnetic collector can be placed above the obtuse angle of the concave die to better play the role of the magnetic collector.

The above embodiment takes a 3-layer coil as an example, the coil can also be a single-layer coil or other multi-layer coils; the winding methods of the multi-layer coil and the single-layer coil are the same, and the multi-layer coil is a single-layer coil. The copper wire is then drawn out and wound in series.

The example shown in the present invention is a flat plate. If the plate material has curved surface characteristics (that is, when the plate material is an arc-shaped part), the lower surface of the magnetic collector can be designed to be a curved surface that conforms to the curved surface characteristics of the plate material to obtain a thick arc surface. Electromagnetic pulse turning and forming device for thick arc-shaped parts; other structures (including the shape parameters of each structure, etc.) in the electromagnetic pulse turning and forming device for thick arc-shaped parts The hole forming apparatus is similarly set up, as shown in FIG. 7 . For example, when the workpiece to be formed has camber features, the lower surface of the magnetic collector structure in the electromagnetic pulse drilling and forming device can be processed into a camber shape to ensure a proper distance between the workpiece and the magnetic collector.

In the present invention, the magnetic collector can preferably be any one of chromium zirconium copper in the prior art, which has good electrical conductivity and high strength. In addition, the present invention can use red copper to wind and form the coil. Since red copper is relatively soft, before being wound into a coil, the red copper can be work-hardened with reference to the prior art to improve the strength of the wire.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (10)

1. An electromagnetic pulse hole flanging forming device for thick plates is characterized by comprising a coil and a magnetic collector (103) positioned on one side of the coil, wherein the magnetic collector (103) is disc-shaped and is provided with an upper disc surface and a lower disc surface which are different in surface area, the upper disc surface and the lower disc surface are plane-shaped, the center of the disc of the magnetic collector (103) is provided with a through hole, and a slit positioned on one side of the central axis of the disc is communicated with the through hole so that the magnetic collector areas on two sides of the slit are completely isolated by the slit;

the coil is a single-layer coil or a multi-layer coil; when the coil is a single-layer coil, the single-layer coil is formed by arranging metal wires (101) around the central axis of the disc in an internal-external distribution manner in the same plane, and the plane is parallel to the upper surface and the lower surface of the magnetic collector (103); when the coils are multilayer coils, any layer of coils in the multilayer coils are arranged inside and outside in the same plane by metal wires (101) around the central axis of the disc, and the plane of each layer of coils is parallel to the upper surface and the lower surface of the magnetic collector (103);

recording the surface with larger surface area of the magnetic collector (103) as an A surface and the surface with smaller surface area as a B surface, wherein the A surface is closer to the coil than the B surface, the B surface is used for being close to a workpiece to be formed, and the coil and the magnetic collector (103) are connected and integrated into a whole through insulating resin; when alternating current is applied to the coil, induced current generated by the coil on the surface A flows to the surface B through the slit, and a larger current density is generated at one end of the magnetic collector (103) close to the surface B by utilizing the area difference of the surface A and the surface B, so that a workpiece to be formed is subjected to a larger electromagnetic force, and the electromagnetic pulse hole flanging forming is facilitated;

and the turn-to-turn pitch of the metal wire (101) is between 2mm and 5 mm; when the coil is a multilayer coil, the interlayer distance is 2mm to 4 mm; a bolt hole is further formed in the winding center of the multilayer coil, and one end of the bolt hole is communicated with a disc center through hole of the magnetic collector (103); fastening bolts are arranged in the bolt holes and used for enhancing the strength of the integral structure after the coil and the magnetic collector (103) are integrated; and the surface of the fastening bolt is also subjected to an insulation treatment.

2. The electromagnetic pulse hole flanging forming device for thick plates of claim 1, characterized in that the cross-sectional shape of said metal wire (101) is rectangular.

3. The electromagnetic pulse hole flanging forming device for thick plates of claim 1, wherein said coil is a 3-layer coil; the metal wire (101) is a red copper wire.

4. The electromagnetic pulse hole flanging forming device for thick plates according to claim 1, characterized in that the magnetic collectors (103) are made of chromium zirconium copper.

5. The electromagnetic pulse hole flanging forming device for thick plate members as claimed in claim 1, wherein said magnetic collector (103) has a thickness twice the skin depth.

6. The electromagnetic pulse hole flanging apparatus for thick plate members as claimed in claim 1, wherein the ratio of the diameter of said a-side to said B-side is not more than 2.

7. The electromagnetic pulse hole flanging apparatus for thick plate members as claimed in claim 6, wherein the ratio of the diameter of said a-side to said B-side is equal to 2.

8. The electromagnetic pulse hole flanging molding apparatus for thick plate members as claimed in claim 1, wherein said insulating resin is an epoxy resin (105).

9. The electromagnetic pulse hole flanging forming device for thick plates of claim 1, wherein said workpiece to be formed is a plate to be formed; the plate to be formed is an aluminum alloy thick plate to be formed, and the thickness of the aluminum alloy thick plate is 7-8 mm.

10. An electromagnetic pulse hole flanging forming device for a thick arc-shaped piece is characterized by comprising a coil and a magnetic collector (103) positioned on one side of the coil, wherein the magnetic collector (103) is disc-shaped and is provided with an upper disc surface and a lower disc surface which have different surface areas, the surface with the larger surface area is plane-shaped, and the surface with the smaller surface area is arc-shaped; a through hole is formed in the center of a disc of the magnetic collector (103), and a slit positioned on one side of the central axis of the disc is communicated with the through hole, so that the magnetic collector areas on two sides of the slit are completely isolated by the slit;

the coil is a single-layer coil or a multi-layer coil; when the coil is a single-layer coil, the single-layer coil is formed by arranging metal wires (101) around the central axis of the disc in an internal-external distribution manner in the same plane, and the plane is parallel to the surface with larger surface area in the magnetic collector (103); when the coils are multilayer coils, any layer of coils in the multilayer coils are arranged inside and outside in the same plane by metal wires (101) around the central axis of the disc, and the plane of each layer of coils is parallel to the surface with larger surface area in the magnetic collector (103);

recording the surface with larger surface area of the magnetic collector (103) as an A surface and the surface with smaller surface area as a B surface, wherein the A surface is closer to the coil than the B surface, the B surface is used for being close to a workpiece to be formed, and the coil and the magnetic collector (103) are connected and integrated into a whole through insulating resin; when alternating current is applied to the coil, induced current generated by the coil on the surface A flows to the surface B through the slit, and a larger current density is generated at one end of the magnetic collector (103) close to the surface B by utilizing the area difference of the surface A and the surface B, so that a workpiece to be formed is subjected to a larger electromagnetic force, and the electromagnetic pulse hole flanging forming is facilitated;

and the turn-to-turn pitch of the metal wire (101) is between 2mm and 5 mm; when the coil is a multilayer coil, the interlayer distance is 2mm to 4 mm; a bolt hole is further formed in the winding center of the multilayer coil, and one end of the bolt hole is communicated with a disc center through hole of the magnetic collector (103); fastening bolts are arranged in the bolt holes and used for enhancing the strength of the integral structure after the coil and the magnetic collector (103) are integrated; and the surface of the fastening bolt is also subjected to an insulation treatment.

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