CN117981907A - Electronic atomizing device, induction coil and method thereof - Google Patents

Abstract

The application provides an electronic atomization device, an induction coil and a method thereof, wherein the electronic atomization device comprises: a susceptor configured to be penetrable by a varying magnetic field to generate heat to heat the liquid substrate to generate an aerosol; an induction coil configured to generate a varying magnetic field; the wire material of the induction coil comprises a plurality of bundles of wire strands, and each bundle of wire strands is formed by twisting a plurality of wires for one time or a plurality of times; wherein the number of wires used in the first twisting of the plurality of wires is between 3 and 20. The induction coil of the electronic atomization device can avoid the occurrence of the wire breakage phenomenon, reduce the alternating current impedance of the induction coil, reduce the loss caused by the internal proximity effect and improve the heating efficiency of the electronic atomization device.

Description

Electronic atomizing device, induction coil and method thereof

Technical Field

The present application relates to the field of electronic atomization technology, and in particular, to an electronic atomization device, an induction coil, and a method thereof.

Background

The electronic atomization device is an electronic product which generates aerosol through atomizing a liquid matrix for users to inhale, and generally comprises an atomizer and a power supply assembly; the atomizer is inside to store and is provided with the atomizing core that is used for atomizing liquid matrix, and power module includes battery and circuit board.

The induction coil of the existing electronic atomization device is easy to break in the twisting process, the alternating current impedance of the coil is large, and the heating efficiency of the electronic atomization device is low.

Disclosure of Invention

In one aspect, the present application provides an electronic atomizing device comprising:

A susceptor configured to be penetrable by a varying magnetic field to generate heat to heat the liquid substrate to generate an aerosol;

An induction coil configured to generate a varying magnetic field; the wire material of the induction coil comprises a plurality of bundles of wire strands, and each bundle of wire strands is formed by twisting a plurality of wires for one time or a plurality of times; wherein the number of wires used in the first twisting of the plurality of wires is between 3 and 20.

In another aspect, the present application provides an induction coil for an electronic atomizing device, wherein a wire material of the induction coil includes a plurality of wire strands, each of the wire strands being formed by twisting a plurality of wires one or more times; wherein the number of wires used in the first twisting of the plurality of wires is between 3 and 20.

In another aspect, the present application also provides a method of forming an induction coil for an electronic atomizing device, the method comprising:

providing 3-20 wires, and twisting for the first time to obtain first-stage wire strands;

providing a plurality of first-stage wire strands, and twisting the plurality of first-stage wire strands for the second time to obtain second-stage wire strands;

Providing a plurality of second-stage wire strands, and forming the wire material of the induction coil after the plurality of second-stage wire strands are twisted for the third time.

The induction coil of the electronic atomization device can avoid the occurrence of the wire breakage phenomenon, reduce the alternating current impedance of the induction coil, reduce the loss caused by the internal proximity effect and improve the heating efficiency of the electronic atomization device.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements, and in which the figures are not to scale, unless expressly stated otherwise.

FIG. 1 is a schematic view of an electronic atomizing device according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an induction coil provided by an embodiment of the present application;

FIG. 3 is a schematic cross-sectional view of a wire material of an induction coil provided by an embodiment of the present application;

FIG. 4 is a schematic cross-sectional view of another wire material of an induction coil provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of another induction coil provided by an embodiment of the present application;

fig. 6 is a schematic diagram of a method of forming an induction coil according to an embodiment of the present application.

Detailed Description

In order that the application may be readily understood, a more particular description thereof will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used in this specification includes any and all combinations of one or more of the associated listed items.

Fig. 1 is a schematic diagram of an electronic atomization device according to an embodiment of the present application.

As shown in fig. 1, the electronic atomizing device 100 includes an atomizer 10 and a power supply assembly 20. The atomizer 10 is removably connected to the power supply assembly 20, and the atomizer 10 and the power supply assembly 20 may be snap-fit, magnetic, etc.

The atomizer 10 includes a susceptor 11 and a reservoir (not shown). The liquid storage cavity is used for storing an atomized liquid matrix; the susceptor 11 is configured to inductively couple with the induction coil 21 to generate heat upon penetration by a varying magnetic field, thereby heating the liquid matrix to generate an aerosol for inhalation.

The liquid matrix preferably comprises a tobacco-containing material comprising volatile tobacco flavour compounds that are released from the liquid matrix upon heating. Alternatively or additionally, the liquid matrix may comprise a non-tobacco material. The liquid matrix may include water, ethanol or other solvents, plant extracts, nicotine solutions, and natural or artificial flavors. Preferably, the liquid matrix further comprises an aerosol former. Examples of suitable aerosol formers are glycerol and propylene glycol.

Generally, the susceptor 11 may be made of at least one of the following materials: aluminum, iron, nickel, copper, bronze, cobalt, plain carbon steel, stainless steel, ferritic stainless steel, martensitic stainless steel, or austenitic stainless steel.

In some exemplary implementations, the susceptor 11 may directly or indirectly contact the liquid substrate, thereby evaporating the liquid substrate by releasing heat. Further, the atomizer 10 further comprises a liquid transfer unit through which the susceptor 11 indirectly contacts the liquid substrate. The liquid transfer unit may be, for example, cotton fiber, metal fiber, ceramic fiber, glass fiber, porous ceramic, etc., and may transfer the liquid matrix stored in the liquid storage chamber to the sensor 11 by capillary action. In some alternative implementations, the susceptor 11 may remain non-contact with the liquid substrate, which heats the liquid substrate by radiating heat.

In some exemplary implementations, the susceptor 11 is configured as a closed loop or non-closed loop tube, the susceptor 11 being wound from a sheet-like metal mesh and supported on the inner surface of the liquid transfer unit.

In some exemplary implementations, the susceptor 11 may further include a radial portion extending radially from one end of the tube, which may be conformed to the end of the liquid transfer unit.

In some exemplary implementations, the susceptor 11 is embedded within the liquid delivery unit and cofired with the liquid delivery unit to form the atomizing core. In this way, the liquid matrix is not atomized by conduction to the contact of the surface of the susceptor 11, but is atomized by heating in the vicinity of the susceptor 11; on the one hand, the heat conduction contact between the receptor 11 and the liquid transfer unit does not produce dry heating, and on the other hand, most of liquid substrates are not in direct contact with the receptor 11 when atomized, so that metal pollution produced by the receptor 11 can be avoided.

In some exemplary implementations, susceptor 11 may include a plurality of spaced closed loops, each closed loop including the same or different metallic material, e.g., the curie temperature points of the materials of the different closed loops are different.

In some exemplary implementations, the susceptor 11 may be a plate-like structure. The susceptor 11 of the plate-like structure may have a plurality of mesh openings thereon.

In some exemplary implementations, the susceptor 11 weighs between 10mg and 30mg. Preferably, between 10mg and 25mg; further preferably, the concentration is between 10mg and 23mg; further preferably, the concentration is 15mg to 23mg; more preferably, the concentration is 18mg to 23mg. In a specific example, the susceptor 11 may weigh 20mg, 21mg, etc.

The power supply assembly 20 includes an induction coil 21, a circuit 22, and a battery cell 23.

The induction coil 21 is configured to generate a varying magnetic field under alternating current.

The circuit 22 may control the overall operation of the electronic atomizing device 100. The circuit 22 controls not only the operation of the battery cell 23 and the induction coil 21, but also the operation of other elements in the electronic atomizing device 100.

In one example, the frequency of the alternating current supplied by circuit 22 to induction coil 21 is between 500KHz and 3MHz; preferably, the frequency can be between 500KHz and 2.5MHz; further preferably, the frequency may be between 500KHz and 2MHz; further preferably, the frequency may be between 500KHz and 1.5MHz; further preferably, the frequency may be between 500KHz and 1MHz. For example, the frequency of the alternating current supplied by the circuit 22 to the induction coil 21 is 500KHZ, or 600KHZ, or 800KHZ, or 1.2MHZ.

The battery 23 provides electrical power for operating the electronic atomizing device 100. The battery 23 may be a rechargeable battery or a disposable battery.

Fig. 2 is a schematic diagram of an induction coil according to an embodiment of the present application.

As shown in fig. 2, the induction coil 21 includes a main body 211, an electrical connection portion 212, and an electrical connection portion 213, and the electrical connection portion 212 and the electrical connection portion 213 are electrically connected to the battery cell 23.

The body 211 is arranged around the susceptor 11 after assembly, and the body 211 may be fitted over a holder (not shown) having a shape similar to the body 211.

Body 211 is a solenoid coil wound from an elongated wire material, such as: the winding and forming process is carried out by adopting 500-2000 wires, or adopting 500-1900 wires, or adopting 700-1900 wires, or adopting 900-1900 wires, or adopting 1000-1900 wires, or adopting 1200-1900 wires, or adopting 1400-1900 wires, or adopting 1600-1900 wires.

The cross-section of the wire material may be rectangular, circular or oval. Preferably rectangular in shape, so that the wire material of the induction coil 21 is of a flat configuration, it is advantageous to increase the number of turns of the induction coil 21 per unit length and thus the inductance value.

The total length of the main body 211 in the axial direction is about 5 to 20mm; in a specific embodiment, the total length of the induction coil 21 in the axial direction is 12.2mm.

The hollow portion of the main body 211 is non-circular in cross section, for example, elliptical; while the cross-section of the body 211 is racetrack shaped. In some examples, the difference between the major and minor axes of the ellipse is between 0.5mm and 2mm. Specifically, the length of the major axis of the ellipse is 8mm to 15mm (preferably, 8mm to 12mm; more preferably, 8mm to 10mm; still more preferably, 9mm to 10 mm); the length of the minor axis of the ellipse is between 8mm and 13mm (preferably between 8mm and 11mm; more preferably between 8mm and 10mm; more preferably between 8mm and 9 mm). In a specific embodiment, the length of the major axis of the ellipse is 9.7mm and the length of the minor axis of the ellipse is 8.9mm. The body 211 having this shape facilitates the fabrication and assembly of the induction coil 21 into the power supply assembly 20.

The number of turns or windings of the solenoid coil is between 4 turns and 20 turns; preferably, between 6 and 20 turns; further preferably, between 6 and 15 turns; further preferably, between 6 and 12 turns; further preferably between 6 and 10 turns. An induction coil 21 with so many turns can provide an effective magnetic field for heating the susceptor 11.

The spacing between adjacent windings may be the same or different. The spacing between adjacent windings is about 0.1-2 mm; or 0.1mm to 1.5mm; or 0.1mm to 1mm; or between 0.1mm and 0.5mm. In a specific embodiment, the spacing between adjacent windings is 0.2 or 0.4mm. It has been found that these specific spacings provide an efficient heating of the susceptor 11 and thus of the liquid substrate.

Fig. 3 is a schematic cross-sectional view of a wire material of an induction coil according to an embodiment of the present application.

As shown in fig. 3, the wire material 30 of the induction coil 21 includes a plurality of wire strands 30c, and each wire strand 30c includes a plurality of wire strands 30b therein. 3-20 wires 30a are arranged in each wire strand 30 b; or 3-18 wires 30a; or 3-16 wires 30a; or 3-14 wires 30a; or 3-12 wires 30a; or 5-12 wires 30a; or 8-12 wires 30a. In a particular embodiment, there may be 10 wires 30a within each bundle of wire strands 30b.

In one embodiment, the wire 30a is made of a low resistivity metal or alloy such as copper, gold, silver, or alloys thereof, and carbon materials (carbon fibers or other conductive carbon materials).

In one embodiment, the wire 30a may be circular or rectangular in cross-section. In a preferred embodiment, the cross section of the wire 30a is circular, which on the one hand avoids breakage and on the other hand facilitates reducing the ac impedance of the induction coil itself.

The verification can be performed by measuring the real part of the equivalent impedance of the induction coil 21 (corresponding to "equivalent impedance 1" in the following table) when the cross-sectional shape of the wire 30a is circular, and the real part of the equivalent impedance of the induction coil 21 (corresponding to "equivalent impedance 2" in the following table) when the cross-sectional shape of the wire 30a is rectangular, with the same conditions of the operating frequency, the number of stranding, the number of wires 30a at the time of the first stranding, and the like (corresponding to "number of wires" in the following table). In the measuring process, the number of the wires 30a in the first twisting is 45 due to the secondary twisting adopted by the twisting times. The measurement results are as follows:

Sequence number	Operating frequency	Number of stranding times	Number of wires	Equivalent impedance 1	Equivalent impedance 2
						1	500KHz	Secondary time	45	22.56mΩ	24.68mΩ
2	1MHz	Secondary time	45	30.46mΩ	32.56mΩ
						3	1.5MHz	Secondary time	45	38.44mΩ	39.96mΩ
4	2MHz	Secondary time	45	46.86mΩ	48.46mΩ
						5	2.5MHz	Secondary time	45	55.47mΩ	57.89mΩ
6	3MHz	Secondary time	45	66.89mΩ	68.38mΩ

As can be seen from the above measurement results, under the same conditions, the value of the equivalent impedance 1 is smaller than the value of the equivalent impedance 2, i.e., the real part of the equivalent impedance of the induction coil 21 when the cross-sectional shape of the wire 30a is circular is smaller than the real part of the equivalent impedance of the induction coil 21 when the cross-sectional shape of the wire 30a is rectangular, even at a higher operating frequency. Therefore, when the cross-sectional shape of the wire 30a is circular, it is advantageous to reduce the ac impedance of the induction coil itself.

In one embodiment, the diameter of wire 30a is desirably between 0.01mm and 0.05mm, corresponding to the varying magnetic field generated by induction coil 21 between 500KHz and 3MHz in the above implementation. In a specific embodiment, the diameter of the wire 30a may be 0.03mm or 0.04mm. The smaller diameter of the wire 30a is beneficial to reducing the influence of the skin effect of the induction coil 21, improving the heating efficiency of the susceptor and improving the atomization speed of the liquid substrate; in addition, induction coils employing smaller wire diameters are advantageous for reducing the size and mass of the susceptor, and for reducing the volume of the atomizer used with the power supply assembly.

In one embodiment, each of the plurality of wire strands 30b may have the same number of wires or may have a different number of wires. For example: one strand 30b has 10 wires 30a, and the other strand 30b has 15 wires 30a.

In one embodiment, 3 to 20 wires 30a are twisted for the first time to obtain a bundle of wire strands 30b, then the bundles of wire strands 30b are twisted for the second time to obtain a bundle of wire strands 30c, and finally the bundles of wire strands 30c are twisted for the third time to form the wire material 30 of the induction coil 21.

The number of strands 30b and the number of strands 30c are not limited, and may be generally determined by the total number of the wires 30a in the induction coil 21. For example: if the main body 211 is formed by winding 1600 wires, 10 wires 30a may be twisted for the first time to obtain a bundle of wire strands 30b, then 16 bundles of wire strands 30b are twisted for the second time to obtain a bundle of wire strands 30c, and finally 10 bundles of wire strands 30c are twisted for the third time to obtain the final product.

In the twisting process, the wires can be twisted in a clockwise or anticlockwise direction.

The induction coil 21 constructed as described above can avoid occurrence of a wire breakage phenomenon, reduce the ac impedance of the induction coil itself, reduce the loss caused by the internal proximity effect, and improve the heat generation efficiency of the electronic atomizing device.

In a further implementation, the surface of each wire 30a in the wire strands 30b may be formed with a layer of insulating material such as insulating paint/film by deposition, spraying, or the like, so as to substantially insulate each wire 30a in the wire strands 30b from each other; in alternative implementations, the insulating material includes, but is not limited to, teflon, polytetrafluoroethylene, polyimide, polyurethane, aromatic amide polymers, and the like.

Each bundle of wire strands 30b further includes a coating layer (not shown) for coating the twisted wire strands 30 a; to prevent or inhibit the wires 30a in the wire strands 30b from unraveling. In a preferred embodiment, the coating is formed using silk-covered wires (e.g., acetate, polyester, etc.) commonly used in cable manufacture.

In one embodiment, the coating layer in each bundle of wire strands 30b is formed by bonding materials such as acetate filaments or polyester filaments to the exterior of the twisted wire strands 30a, bonding them together by a hot air self-adhesion or acetone self-adhesion process, and curing. The hot air self-adhesion process is to heat a die through hot air when the acetate fiber wires or the polyester fiber wires are wound outside the twisted wires 30a, so that the temperature of the die reaches the bonding temperature of the wires, and the acetate fiber wires or the polyester fiber wires are bonded and molded outside the wires 30a to form a coating layer; the acetone self-adhesion process is to coat or spray acetone on the surface of the wires through a felt or a nozzle in the process of winding the acetate wires outside the twisted wires 30a, adhere the acetate wires together through the acetone, and form a coating layer after solidification.

Or in yet another variant, the coating in the above strand 30b is obtained in a manner similar to the surface coating after the inner filling in the preparation of optical fibers/cables and the like. In particular embodiments, the gaps between the wires 30a are filled during twisting with a filler such as polyethylene, polyvinyl chloride (PVC), or nylon, and then covered with a covering material such as phenolic resin, alkyd resin, nitrile rubber, or ethylene propylene diene monomer. It is advantageous to prevent the wires 30a in the wire strands 30b from being scattered and slipped off after the preparation.

Further in practice, the plurality of conductor strands 30b or the plurality of conductor strands 30c are insulated from each other, as well, using similar coatings as described above.

Fig. 4 is a schematic cross-sectional view of another wire material of an induction coil provided by an embodiment of the present application.

Unlike fig. 3, the wire material 40 shown in fig. 4 includes a plurality of wire strands 40a, and the wire material 40 of the induction coil 21 is formed by twisting the plurality of wire strands 40a fourth time. Wherein each bundle of wire strands 40a is similar to the wire material 30 shown in fig. 3, i.e., is formed after three twists.

The wire material 40 formed after four twisting can further avoid the occurrence of the wire breakage phenomenon and reduce the alternating current impedance of the induction coil. It has been found that the above object is achieved by a wire material formed after three or more stranding steps. For reasons of cost of the twisting process, it is preferable to form the wire material using three or four twisting processes.

To further verify the effect of the number of twists and the number of wires 30a at the first twist, the inventors selected two different sets of measurement conditions to measure the real part of equivalent impedance: one is that the number of stranding times is twice, and the number of wires 30a at the first stranding is 45 (corresponding "equivalent impedance 3" in the following table); the other is that the number of stranding times is four, and the number of wires 30a at the first stranding is 10 (corresponding "equivalent impedance 4" in the following table); other measurement conditions are the same, for example: the working frequency is 500 KHz-3 MHz, and the cross section shape of the lead 30a is round. The measurement was performed using an impedance analyzer, and the measurement results were as follows:

Sequence number	Operating frequency	Cross-sectional shape of wire	Equivalent impedance 3	Equivalent impedance 4
					1	500KHz	Round shape	22.56mΩ	14.09mΩ
2	1MHz	Round shape	30.46mΩ	16.15mΩ
					3	1.5MHz	Round shape	38.44mΩ	18.33mΩ
4	2MHz	Round shape	46.86mΩ	20.83mΩ
					5	2.5MHz	Round shape	55.47mΩ	24.28mΩ
6	3MHz	Round shape	66.89mΩ	28.47mΩ

As can be seen from the above measurement results, the number of stranding times was four, and the ac impedance was small when the number of wires 30a at the first stranding was 10; the ac impedance drop is very large compared with the case where the number of wires 30a at the first twisting is 45, which is the case where the number of twisting is two. Therefore, the wire strands of the induction coil use a lower number of wires (for example, 3-20 wires) when being twisted for the first time, and the twisting times (for example, more than three times) are increased, so that the electromagnetic coupling efficiency can be promoted, the heating speed of the susceptor in operation is improved, and the electronic atomization device can generate aerosol in a very short time after being started, thereby meeting the use requirement that the electronic atomization device containing liquid matrix can be sucked almost without waiting after being started.

In addition, "the number of stranding times is four, the number of the wires 30a is 10 at the first stranding", and the wire breakage phenomenon does not occur during the stranding process; and the number of twisting times is twice, the number of wires 30a is 45 at the first twisting, and the wire breakage phenomenon occurs.

Fig. 5 is a schematic diagram of another induction coil according to an embodiment of the present application.

As shown in fig. 5, the induction coil 21a is configured as a planar spiral coil. The wire material of the planar spiral coil is also formed by twisting a plurality of wires 30a plurality of times; wherein the number of wires 30a in the first twist is between 3 and 20. The number of stranding is preferably three or four stranding processes.

The planar spiral coil may be arranged along a longitudinal direction perpendicular to the aerosol-generating device 100 or along the longitudinal direction of the aerosol-generating device 100. The planar spiral coil may be supported by a sheet-like or plate-like support member parallel to the planar induction coil 21a, or may be embedded in other members.

Fig. 6 is a schematic diagram of a method of forming an induction coil according to an embodiment of the present application.

As shown in fig. 6, the method includes:

Step S11, providing 3-20 wires, and obtaining a first-stage wire strand after first twisting;

Step S12, providing a plurality of first-stage wire strands, and twisting the first-stage wire strands for the second time to obtain second-stage wire strands;

Each of the plurality of first stage strands may have the same number of wires or may have a different number of wires.

And step S13, providing a plurality of second-stage wire strands, and forming the wire material of the induction coil after the second-stage wire strands are twisted for the third time.

In an example, the method further comprises:

The multi-beam second-stage wire strand is twisted for the third time to obtain a third-stage wire strand;

Providing a plurality of third-stage wire strands, and forming the wire material of the induction coil after the plurality of third-stage wire strands are twisted for the fourth time.

It should be noted that while the present application has been illustrated in the drawings and described in connection with the preferred embodiments thereof, it is to be understood that the application may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but are to be construed as providing a full breadth of the disclosure. The above-described features are further combined with each other to form various embodiments not listed above, and are considered to be the scope of the present application described in the specification; further, modifications and variations of the present application may be apparent to those skilled in the art in light of the foregoing teachings, and all such modifications and variations are intended to be included within the scope of this application as defined in the appended claims.

Claims (15)

1. An electronic atomizing device, comprising:

A susceptor configured to be penetrable by a varying magnetic field to generate heat to heat the liquid substrate to generate an aerosol;

An induction coil configured to generate a varying magnetic field; the wire material of the induction coil comprises a plurality of bundles of wire strands, and each bundle of wire strands is formed by twisting a plurality of wires for one time or a plurality of times; wherein the number of wires used in the first twisting of the plurality of wires is between 3 and 20.

2. The electronic atomizing device of claim 1, wherein the strand of wire is formed from a plurality of wires twisted at least twice.

3. The electronic atomizing device of claim 2, wherein the strand is twisted three or four times.

4. The electronic atomizing device of claim 1, wherein the wire has a circular cross-sectional shape.

5. The electronic atomizing device of claim 1, wherein the wire has a diameter of 0.01mm to 0.05mm.

6. The electronic atomizing device of claim 1, wherein the wire material of the induction coil comprises 500 to 2000 wires.

7. The electronic atomizing device of claim 1, wherein the operating frequency of the induction coil is between 500KHz and 3MHz.

8. The electronic atomizing device of claim 1, wherein the induction coil is configured as a solenoid coil.

9. The electronic atomizing device of claim 8, wherein a cross-section of the hollow portion of the solenoid coil is elliptical.

10. The electronic atomizing device of claim 8, wherein the number of turns of the solenoid coil is between 4 turns and 20 turns.

11. The electronic atomizing device of claim 8, wherein a pitch between adjacent turns of the solenoid coil is between 0.1mm and 2mm.

12. The electronic atomizing device of claim 1, wherein the induction coil is configured as a planar spiral coil.

13. An induction coil for an electronic atomizing device, the induction coil configured to generate a varying magnetic field; the induction coil is characterized in that the wire material of the induction coil comprises a plurality of wire strands, and each wire strand is formed by twisting a plurality of wires once or a plurality of times; wherein the number of wires used in the first twisting of the plurality of wires is between 3 and 20.

14. A method of forming an induction coil for an electronic atomizing device, the method comprising:

providing 3-20 wires, and twisting for the first time to obtain first-stage wire strands;

providing a plurality of first-stage wire strands, and twisting the plurality of first-stage wire strands for the second time to obtain second-stage wire strands;

Providing a plurality of second-stage wire strands, and forming the wire material of the induction coil after the plurality of second-stage wire strands are twisted for the third time.

15. The method as recited in claim 14, further comprising:

The multi-beam second-stage wire strand is twisted for the third time to obtain a third-stage wire strand;

Providing a plurality of third-stage wire strands, and forming the wire material of the induction coil after the plurality of third-stage wire strands are twisted for the fourth time.