Plane uniform magnetic pressure generating device based on spiral pipeline coil

Abstract

A planar uniform magnetic pressure generating device based on a spiral pipeline coil comprises a pulse current generating device, the spiral pipeline coil, a magnetic collector, a guide frame, a mold and a plate. The pulse current generating device is electrically connected with the spiral pipeline coil, the magnetic collector is divided into an upper part and a lower part, the upper part is of a cylindrical structure with a circular longitudinal section, the lower part is of a polygon with a gap, a penetrating gap is formed in the lower end of the upper part, and the lower part and the upper part are connected through one side or two sides of the gap; the spiral pipe coil is arranged in a cylinder structure on the upper portion of the magnetic collector, the die is arranged in the guide frame, the lower portion of the magnetic collector is located above the guide frame, an insulation pressing plate is arranged between the lower portion of the magnetic collector and the guide frame, and a plate material is arranged between the insulation pressing plate and the guide frame. The forming device is reasonable in structural design, has the characteristics of high coil strength, large energy density and good magnetic force uniformity, has low requirements on die materials and sizes, is good in adaptability, and is suitable for forming difficult-to-deform metal sheets such as aluminum alloy, magnesium alloy and titanium alloy.

Description

Technical Field

[0001] The utility model belongs to the technical field of electromagnetic forming and relates to a planar uniform magnetic pressure generating device based on a spiral tube coil. Background Art

[0002] Electromagnetic forming is a high strain rate forming method that uses the strong Lorentz force on a current-carrying conductor in a magnetic field to cause it to move at high speed and form. It can effectively improve the forming performance of metal sheets and reduce unloading springback. It is particularly suitable for the forming of thin metal sheets that are difficult to deform, such as aluminum alloys, magnesium alloys, and titanium alloys. When using the electromagnetic forming process to form a planar array structure, the uniformity of the magnetic pressure is very important.

[0003] After investigation, the existing "Journal of Huazhong University of Science and Technology (Natural Science Edition)", Volume 39, Issue 2, published in February 2011, "Study on Uniform Pressure Coil and Sheet Material Force during Flat Electromagnetic Forming", introduced a uniform pressure coil that can generate relatively uniform magnetic pressure. The uniform pressure coil used in this type of metal sheet electromagnetic forming method is a guide frame coil, which mainly includes a three-dimensional spiral coil and an outer guide frame, and is encapsulated by epoxy resin. However, epoxy resin is very easy to crack during electromagnetic forming, causing damage to the coil or even scrapping; secondly, there is a large gap between each turn of the coil in this coil structure, which not only causes insufficient coil forming ability, but also causes the generated magnetic pressure to be generally uniform.

[0004] In addition, the invention patent with publication number CN116967340A proposes to use a spiral tube coil plus a current collector to generate current in the same direction in two parallel sheets, and to deform them by moving them toward the mold through electromagnetic attraction. However, this method requires the mold to be relatively thin and the conductivity to be relatively poor, resulting in poor adaptability. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a planar uniform magnetic pressure generating device based on a spiral tube coil with reasonable structural design, high coil strength and high energy density, low requirements on mold materials and dimensions, and good adaptability.

[0006] The technical solution adopted by the utility model to solve the above technical problems is: a planar uniform magnetic pressure generating device based on a spiral tube coil, characterized in that it includes a pulse current generating device, a spiral tube coil, a magnetism collector, a guide frame, a mold and a sheet material; the pulse current generating device is electrically connected to the spiral tube coil, the magnetism collector is divided into an upper and lower part, wherein the upper part is a cylindrical structure with a circular longitudinal section that matches the spiral tube coil, a through gap is opened at the lower end of the upper part, and the lower part is connected to the upper part through one side or both sides of the gap; the spiral tube coil is placed in the upper cylindrical structure of the magnetism collector, the mold is placed in the guide frame, the lower part of the magnetism collector is located above the guide frame, an insulating pressure plate is provided between the lower part of the magnetism collector and the guide frame, and the sheet material is arranged between the insulating pressure plate and the guide frame.

[0007] As an improvement, the spiral tube coil is composed of a copper wire with an insulating layer and a coil frame. The wire is tightly wound on the coil frame in a spiral form. The gap is opened in the middle position between the upper lower end and the lower upper end of the magnetic collector. The length of the lower part is consistent with that of the upper part. When the lower part and the upper part of the magnetic collector are connected through both sides of the gap, the longitudinal section of the lower part of the magnetic collector is a hollow rectangle; when the lower part and the upper part of the magnetic collector are connected through one side of the gap, the lower part of the magnetic collector is an L-shaped plate structure.

[0008] Furthermore, the material of the magnetic collector is copper alloy, aluminum alloy or iron-based alloy, and the thickness of the upper part of the magnetic collector is greater than the skin depth of the pulse current, which is 4mm-15mm. When the lower part and the upper part of the magnetic collector are connected through both sides of the gap to form a loop, the thickness of the lower part of the magnetic collector adjacent to the sheet material is less than the skin depth of the pulse current, which is 0.2mm-2mm; when the lower part and the upper part of the magnetic collector are connected through one side of the gap, the thickness of the lower part of the magnetic collector needs to be greater than 2 times the skin depth of the pulse current, which is 5mm-15mm.

[0009] Furthermore, a cylindrical reinforcement frame is sleeved on the outer side of the upper part of the magnetic collector, and the reinforcement frame is made of iron-based alloy or titanium alloy.

[0010] Furthermore, the pulse current generating device is composed of a DC power supply, a capacitor, a first switch and a second switch. The first switch, the capacitor and the spiral tube coil are connected in series to form a discharge circuit. The second switch and the DC power supply are connected in series and then in parallel at both ends of the capacitor to form a charging circuit.

[0011] Furthermore, the guide frame is a rectangular frame, the material of the guide frame is copper alloy, aluminum alloy or iron-based alloy, the upper end surface of the guide frame is formed with a groove for inserting the mold, the length of the guide frame is consistent with the length of the magnetic collector, and the width of the guide frame is smaller than the width of the magnetic collector.

[0012] Furthermore, the guide frame is arranged on a base, and the base is composed of a base fixing plate and a base insulating layer, and the base insulating layer is fixedly arranged on the base fixing plate.

[0013] Furthermore, a pressure plate is provided on the lower inner bottom surface of the magnetic collector, the width of the pressure plate is consistent with the guide frame, and the length is greater than the length of the magnetic collector. The front and rear ends of the pressure plate extend out of the magnetic collector and are fixed to the base by bolts.

[0014] Finally, the inner and outer surfaces of the magnetic collector are covered with an insulating layer, and the surface of the guide frame adjacent to the mold is covered with an insulating layer, which is a polyimide insulating layer with a thickness of 0.1-0.3 mm.

[0015] Compared with the prior art, the advantages of the utility model are: the magnetism collector is divided into two parts, the upper part is covered on the outside of the spiral tube coil, the lower part is connected to the upper part through one side or both sides of the gap, the mold is placed inside the guide frame, the insulating pressure plate is placed between the guide frame and the lower half of the magnetism collector, the sheet material is placed between the guide frame and the insulating pressure plate during forming, the thickness of the upper half of the magnetism collector is greater than the pulse current skin depth, and the thickness of the lower half and the adjacent part of the sheet material is less than the pulse current skin depth; the edge plate and the base are connected by bolts, so that the edge of the sheet material can be pressed and good electrical contact between the sheet material and the guide frame can be ensured. The utility model has a reasonable structural design, which effectively solves the current problems of low strength, poor adaptability, and general magnetic pressure uniformity of the flat uniform pressure coil. It has the characteristics of high coil strength and good magnetic uniformity. At the same time, it has low requirements on mold materials and dimensions, good adaptability, and is suitable for the forming of difficult-to-deform metal sheets such as aluminum alloys, magnesium alloys and titanium alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of Embodiment 1 of the present utility model;

[0017] Figure 2 yes Figure 1 Left view of

[0018] Figure 3 is a schematic diagram of the structure of the magnetic collector in Example 1, wherein the arrows represent the direction and distribution of the current;

[0019] Figure 4 It is a schematic diagram of the structure of the magnetic collector in Example 2, wherein the arrows represent the direction and distribution of the current. DETAILED DESCRIPTION

[0020] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0021] Example 1

[0022] like Figure 1 , 2As shown in Figure 3, a planar uniform magnetic pressure generating device based on a spiral tube coil comprises a pulse current generating device 3, a spiral tube coil 2, a magnetizer 1, a guide frame 4, a mold 7 and a sheet material 10; the pulse current generating device 3 is electrically connected to the spiral tube coil 2, and the magnetizer 1 is divided into an upper and lower part, wherein the upper part 11 is a cylindrical structure with a circular longitudinal section that matches the spiral tube coil 2, and the lower part 12 is a hollow structure with a rectangular longitudinal section, and the lower end of the upper part 11 and the upper end of the lower part 12 are respectively provided with through gaps, and the lower part 12 is connected to the upper part 11 through the two sides of the gap; the spiral tube coil 2 is placed in the cylindrical structure of the upper part 11 of the magnetizer 1, the mold 7 is placed in the guide frame 4, the lower part 12 of the magnetizer 1 is located above the guide frame 4, an insulating pressure plate 5 is provided between the lower part 12 of the magnetizer 1 and the guide frame 4, and the sheet material 10 is arranged between the insulating pressure plate 5 and the guide frame 4 during forming.

[0023] The specific structure is as follows: the spiral tube coil 2 is composed of a copper wire with an insulating layer and a coil frame, and the wire is tightly wound on the coil frame in a spiral form. The gap of the magnetic collector 1 is opened in the middle position between the lower end of the upper part 11 and the upper end of the lower part 12 of the magnetic collector 1, and the length of the lower part 12 is consistent with that of the upper part 11. The outer side of the upper part of the magnetic collector 1 is sleeved with a cylindrical reinforcement frame 8, and the reinforcement frame 8 is made of an iron-based alloy or a titanium alloy. The pulse current generating device 3 is composed of a DC power supply, a capacitor, a first switch K1 and a second switch K2. The first switch K1, the capacitor C1 and the spiral tube coil 1 are connected in series to form a discharge circuit. The second switch K2 and the DC power supply E1 are connected in series and connected in parallel at both ends of the capacitor C1 to form a charging circuit. The guide frame 4 is a rectangular frame. The material of the guide frame 4 is a copper alloy, an aluminum alloy or an iron-based alloy. The upper end surface of the guide frame 4 is formed with a groove for the mold 7 to be placed. The length of the guide frame 4 is consistent with the length of the magnetic collector 1, and the width of the guide frame 4 is less than the width of the magnetic collector 1. The guide frame 4 is arranged on the base 9, which is composed of a base fixing plate 92 and a base insulating layer 91, and the base insulating layer 92 is fixedly arranged on the base fixing plate 91. A pressure plate 6 is arranged on the bottom surface of the lower inner side of the magnetism collector 1, and the width of the pressure plate 6 is consistent with that of the guide frame 4, and the length is greater than the length of the magnetism collector 1. The front and rear ends of the pressure plate 6 extend out of the magnetism collector 1 and are connected and fixed to the base 9 by bolts. The inner and outer surfaces of the magnetism collector 1 and the surfaces adjacent to the guide frame 4 and the mold 7 are covered with a 0.15mm thick polyimide insulating layer to prevent breakdown and sparking between the magnetism collector 1 and the sheet material 10, the pressure plate 6, the spiral tube coil 2, etc., and between the guide frame 4 and the mold 7 under high voltage conditions.

[0024] The material of the magnetic collector 1 is copper alloy, aluminum alloy or iron-based alloy. The thickness of the upper part of the magnetic collector 1 is greater than the skin depth of the pulse current, which is 4mm-15mm. When the lower part 12 and the upper part 11 of the magnetic collector 1 are connected through the two sides of the gap to form a loop, the thickness of the lower part 12 of the magnetic collector 1 adjacent to the sheet 10 is less than the skin depth of the pulse current, which is 0.2mm-2mm.

[0025] In this embodiment, the pulse current generating device 3 generates a pulse current with a frequency of 2*10 4 Hz, the material of the magnetic collector 1 is H62 brass (resistivity is 7.1*10 -8 Ω·m, relative magnetic permeability is close to 1), according to the skin depth calculation formula:

[0026]

[0027] in:

[0028] δ is the skin depth;

[0029] ρ is the resistivity of the material;

[0030] f is the pulse current frequency;

[0031] μ=μ0μ r is the absolute magnetic permeability of the material, μ r is the relative magnetic permeability, μ0=4π*10 -7 H / m is the magnetic permeability of vacuum.

[0032] It can be obtained that the skin depth of the pulse current of this frequency in the present magnetism collector is 0.95 mm, so the thickness L of the upper part 11 of the present magnetism collector 1 is selected to be 5 mm, and the thickness d of the lower part 12 adjacent to the sheet material 10 is selected to be 0.8 mm.

[0033] Example 2

[0034] A planar uniform magnetic pressure generating device based on a spiral tube coil, which is different from the embodiment 1 in that the cross section of the lower part 12 of the magnetic collector 1 is an L-shaped plate structure, the lower part 12 of the magnetic collector 1 is connected to the upper part 11 through one side of the gap, and the shape of the magnetic collector 1 is as follows Figure 4 As shown, its material is 2024 aluminum alloy (resistivity is 5.8*10 -8 Ω·m, relative magnetic permeability is close to 1).

[0035] The pulse current generating device 3 in the present embodiment generates a pulse current with a frequency of 1*10 4 Hz. According to the calculation formula of skin depth, the skin depth of the pulse current of this frequency in the magnetism collector 1 is 1.2mm, so the thickness of the upper part 11 and the lower part 12 of the magnetism collector 1 is greater than 2.4mm. To ensure the strength of the magnetism collector 1, the thickness L1 and d1 of the upper part 11 and the lower part 12 of the magnetism collector 1 are both selected to be 6mm.

[0036] The other parts of the structure of Example 2 are the same as those of Example 1.

[0037] The utility model effectively solves the current problems of low strength, poor adaptability, and general magnetic pressure uniformity of the flat uniform pressure coil. It has the characteristics of high coil strength and good magnetic force uniformity. At the same time, it has low requirements on mold materials and dimensions and good adaptability. It is suitable for the forming of difficult-to-deform metal thin plates such as aluminum alloys, magnesium alloys, and titanium alloys.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A planar uniform magnetic pressure generating device based on a spiral tube coil, characterized in that: It includes a pulse current generating device, a spiral tube coil, a magnetism collector, a guide frame, a mold and a sheet material; the pulse current generating device is electrically connected to the spiral tube coil, the magnetism collector is divided into an upper and lower part, wherein the upper part is a cylindrical structure with a circular longitudinal section matching the spiral tube coil, a through gap is opened at the lower end of the upper part, and the lower part is connected to the upper part through one side or both sides of the gap; the spiral tube coil is placed in the upper cylindrical structure of the magnetism collector, the mold is placed in the guide frame, the lower part of the magnetism collector is located above the guide frame, an insulating pressure plate is provided between the lower part of the magnetism collector and the guide frame, and the sheet material is arranged between the insulating pressure plate and the guide frame.

2. The planar uniform magnetic pressure generating device according to claim 1, characterized in that: The spiral tube coil is composed of a copper wire with an insulating layer and a coil frame. The wire is tightly wound on the coil frame in a spiral form. A gap is opened in the middle position between the upper lower end and the lower upper end of the magnetic collector. The length of the lower part is consistent with that of the upper part. When the lower part and the upper part of the magnetic collector are connected through the two sides of the gap, the longitudinal section of the lower part of the magnetic collector is a hollow rectangle; when the lower part and the upper part of the magnetic collector are connected through one side of the gap, the lower part of the magnetic collector is an L-shaped plate structure.

3. The planar uniform magnetic pressure generating device according to claim 2, characterized in that: The material of the magnetic collector is copper alloy, aluminum alloy or iron-based alloy. The thickness of the upper part of the magnetic collector is greater than the skin depth of the pulse current, which is 4mm-15mm. When the lower part and the upper part of the magnetic collector are connected through the two sides of the gap to form a loop, the thickness of the lower part of the magnetic collector adjacent to the sheet material is less than the skin depth of the pulse current, which is 0.2mm-2mm; when the lower part and the upper part of the magnetic collector are connected through one side of the gap, the thickness of the lower part of the magnetic collector needs to be greater than 2 times the skin depth of the pulse current, which is 4mm-15mm.

4. The planar uniform magnetic pressure generating device according to claim 3, characterized in that: A cylindrical reinforcement frame is sleeved on the outer side of the upper part of the magnetic collector, and the reinforcement frame is made of iron-based alloy or titanium alloy.

5. The planar uniform magnetic pressure generating device according to claim 1, characterized in that: The pulse current generating device is composed of a DC power supply, a capacitor, a first switch and a second switch. The first switch, the capacitor and the spiral tube coil are connected in series to form a discharge circuit. The second switch and the DC power supply are connected in series and then in parallel at both ends of the capacitor to form a charging circuit.

6. The planar uniform magnetic pressure generating device according to claim 1, characterized in that: The guide frame is a rectangular frame, and the material of the guide frame is copper alloy, aluminum alloy or iron-based alloy. The upper end surface of the guide frame is formed with a groove for inserting the mold. The length of the guide frame is consistent with the length of the magnetic collector, and the width of the guide frame is smaller than the width of the magnetic collector.

7. The planar uniform magnetic pressure generating device according to claim 6, characterized in that: The guide frame is arranged on a base, and the base is composed of a base fixing plate and a base insulating layer, and the base insulating layer is fixedly arranged on the base fixing plate.

8. The planar uniform magnetic pressure generating device according to claim 7, characterized in that: A pressure plate is provided on the bottom inner surface of the lower part of the magnetic collector. The width of the pressure plate is consistent with the guide frame and the length is greater than the length of the magnetic collector. The front and rear ends of the pressure plate extend out of the magnetic collector and are connected and fixed to the base by bolts.

9. The planar uniform magnetic pressure generating device according to any one of claims 1 to 8, characterized in that: The inner and outer surfaces of the magnetic collector are both covered with an insulating layer, and the surface of the guide frame adjacent to the mold is covered with an insulating layer, which is a polyimide insulating layer with a thickness of 0.1-0.3 mm.

Images