Induction coil

Abstract

The utility model provides an induction coil, and relates to induction heating equipment technical field, the induction coil comprises a coil body, a coil electrode and two connecting pipes, the coil body is formed by spiral coiling of a square metal pipe, the coil body is in a conical spiral structure, the coil body comprises a plurality of coil layers which are coaxially arranged and distributed in a laminated manner, the two ends of the coil body are fixedly connected with the coil electrodes through connecting pipes respectively, and the outer wall of the square metal pipe and the outer walls of the connecting pipes are coated with insulating layers respectively. According to the induction coil provided by the utility model, the coaxiality and the roundness of the coil can be effectively ensured, and the ignition risk of the induction coil is reduced.

Description

Technical Field

[0001] This utility model relates to the field of induction heating equipment technology, and in particular to an induction coil. Background Technology

[0002] The induction coil is the core component of induction heating equipment. When high-frequency alternating current passes through the induction coil, a rapidly changing magnetic field is generated around it. If a metal workpiece (such as a metal rod) is placed in this magnetic field, eddy currents will be induced inside the metal workpiece, thereby generating heat using the workpiece's own resistance, achieving the purpose of heating.

[0003] In the manufacturing, installation, and maintenance of induction coils, ensuring the roundness of each turn, the uniformity of the inter-turn distance, and the concentricity of the entire coil are crucial basic requirements. However, induction coils are generally conical spiral coils wound from round copper tubes, making it difficult to guarantee that each turn is coaxial and circular during the winding process. This often leads to uneven heating of the induction coil, reduced efficiency, shortened coil life, and even catastrophic failures.

[0004] Chinese patent application number 202422530638.8 proposes an induction coil for melting metal bars, which can ensure the coaxiality of the coil, but the deformation at the transition between turns is too large, and the roundness of each turn of the coil still cannot be guaranteed.

[0005] In addition, existing induction coils are made of circular metal tubes wound together, and the current is mainly concentrated near the inner bar material side. The current density is high, which can easily cause overcurrent and arcing, posing a risk of burning out the induction coil or even the entire induction furnace. Utility Model Content

[0006] The purpose of this invention is to provide an induction coil that can effectively ensure the coaxiality and roundness of the induction coil and reduce the risk of arcing.

[0007] To achieve the above objectives, this utility model proposes an induction coil, wherein the induction coil includes a coil body, coil electrodes and two connecting tubes. The coil body is formed by spirally winding a square metal tube and has a conical spiral structure. The coil body includes multiple coaxially arranged and stacked coil layers. The two ends of the coil body are respectively fixedly connected to the coil electrodes through the connecting tubes. The outer walls of the square metal tube and the outer walls of the connecting tubes are respectively covered with an insulating layer.

[0008] The induction coil as described above, wherein multiple coil layers are stacked axially, the outer sidewalls of each coil layer together form a first conical surface, and the inner sidewalls of each coil layer together form a second conical surface.

[0009] The induction coil as described above, wherein the first conical surface is parallel to the second conical surface.

[0010] In the induction coil described above, the angle between the apex angles of the first and second conical surfaces ranges from 40 to 70 degrees.

[0011] The induction coil as described above, wherein each of the coil layers is composed of multiple helical segments.

[0012] The induction coil as described above, wherein each of the coil layers comprises three helical segments.

[0013] In the induction coil described above, with the starting point of each turn being 0 turns, the three spiral segments are respectively a first spiral segment with 0 turns to less than 0.2 turns, a second spiral segment with more than 0.2 turns to less than 0.9 turns, and a third spiral segment with more than 0.9 turns to 1 turn.

[0014] The induction coil as described above includes, from top to bottom, an uppermost coil layer, a second coil layer, and a lowermost coil layer; in the second coil layer and the lowermost coil layer, the pitch of the first helical segment and the pitch of the third helical segment are 1.6P ± 0.3P, and the pitch of the second helical segment is P; in the uppermost coil layer, the pitch of the first helical segment is 1.6P ± 0.3P, the pitch of the first helical segment is 0.6P ± 0.2P, and the pitch of the first helical segment is 0.4P ± 0.2P; where P is a preset reference pitch.

[0015] The induction coil described above, wherein the coil body is 3D printed, and each of the spiral segments has different geometric parameters, the geometric parameters being selected from at least one of spiral radius, spiral helix angle, and axial pitch.

[0016] The induction coil described above, wherein the insulating layer is a ceramic insulating layer. Compared with the prior art, the present invention has the following features and advantages:

[0017] The induction coil proposed in this invention is used to melt metal rods. Its coil body is made of a square metal tube spirally wound. The long side of the square metal tube is parallel to the electromagnetic lines of the induction coil, which can effectively reduce the local current density of the induction coil and reduce the risk of arcing of the induction coil.

[0018] The induction coil proposed in this invention uses 3D printing process parameters set according to a 3D model. This allows for control of the helical radius, helical angle, and position of each coil layer, ensuring a high degree of consistency between the coil body and the designed 3D model. This guarantees the symmetry, uniformity, and expected gradient distribution of the magnetic field generated by the induction coil. Furthermore, the coil body is integrally formed by 3D printing, improving its mechanical strength and enabling it to better withstand the impact and vibration from electromagnetic forces. Additionally, once the 3D printing process parameters are set, the coil bodies obtained through 3D printing maintain a high degree of consistency, achieving digitalization and customization of coil body processing. Attached Figure Description

[0019] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, under the guidance of this invention, can select various possible shapes and proportions to implement this invention according to specific circumstances.

[0020] Figure 1 This is a perspective view of the induction coil proposed in this utility model;

[0021] Figure 2 This is a front view of the induction coil in this utility model;

[0022] Figure 3 This is a top view of the induction coil in this utility model;

[0023] Figure 4 This is a side view of the induction coil in this utility model;

[0024] Figure 5 This is a schematic diagram of the square metal tube in this utility model;

[0025] Figure 6 This is a schematic diagram showing the position of the induction coil layer in this utility model;

[0026] Figure 7 This is a schematic diagram of the coil body in this utility model.

[0027] Explanation of reference numerals in the attached figures

[0028] 100. Induction coil; 10. Coil body; 101. Uppermost coil layer; 102. Second coil layer; 103. Lowermost coil layer; 11. Helical segment; 12. Transition circular tube segment; 20. Coil electrode; 30. Connecting tube; 40. First conical surface; 50. Second conical surface. Detailed Implementation

[0029] The details of this utility model can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of this utility model described herein are for illustrative purposes only and should not be construed as limiting the utility model in any way. Under the teachings of this utility model, those skilled in the art can conceive of any possible modifications based on this utility model, and these should all be considered to fall within the scope of this utility model.

[0030] like Figures 1 to 5 As shown, this utility model proposes an induction coil 100, which includes a coil body 10, a coil electrode 20 and two connecting tubes 30. The coil body 10 is formed by spirally winding a square metal tube. The coil body 10 has a conical spiral structure and includes multiple coaxially arranged and stacked coil layers in the radial direction. The two ends of the square cross-section metal tube are fixedly connected to the coil electrode 20 through the connecting tubes 30, and the outer wall of the square cross-section metal tube and the outer wall of the connecting tubes 30 are respectively covered with an insulating layer.

[0031] The induction coil 100 proposed in this utility model is used to melt a metal rod. Its coil body 10 is made of a square metal tube spirally wound. The long side of the square metal tube is parallel to the electromagnetic line of the induction coil 100, which can effectively reduce the local current density of the induction coil 100 and reduce the risk of arcing of the induction coil 100.

[0032] In one optional embodiment of this utility model, such as Figure 6 As shown, multiple coil layers are stacked along the axial direction, with the outer sidewalls of each coil layer forming a first conical surface 40 and the inner sidewalls of each coil layer forming a second conical surface 50.

[0033] In one optional example of this implementation, the first conical surface 40 is parallel to the second conical surface 50.

[0034] Preferred, such as Figure 7 As shown, the angle range of the apex angle α of the first cone surface 40 and the second cone surface 50 is 40 to 70 degrees.

[0035] In one optional embodiment of this utility model, each coil layer is formed by sequentially splicing together multiple spiral segments 11.

[0036] In one alternative embodiment of this implementation, each coil layer includes three helical segments 11.

[0037] In an optional example, with the starting point of each turn being turn 0, the three spiral segments are the first spiral segment from 0 turns to less than 0.2 turns, the second spiral segment from more than 0.2 turns to less than 0.9 turns, and the third spiral segment from more than 0.9 turns to 1 turn.

[0038] Preferably, the coil body 10 includes an uppermost coil layer 101, a second coil layer 102, and a lowermost coil layer 103 arranged sequentially from top to bottom; in the second coil layer 102 and the lowermost coil layer 103, the pitch of the first helical segment and the pitch of the triple helical segment are 1.6P±0.3P, and the pitch of the second helical segment is P; in the uppermost coil layer 101, the pitch of the first helical segment is 1.6P±0.3P, the pitch of the second helical segment is 0.6P±0.2P, and the pitch of the third helical segment is 0.4P±0.2P; wherein, P is a preset reference pitch.

[0039] Furthermore, the tilt angle β (the angle with the horizontal plane) of the uppermost coil layer 101 is less than 15 degrees.

[0040] In one optional example, the diameter of the conical helix at the starting position of the bottom coil layer 103 is D; the diameter at the ending position of the top coil layer 101 is 1.5D-3D. The diameter of the helix segment at each small position between the starting and ending positions can be adjusted appropriately to ensure that the inner and outer sidewalls of each coil layer are parallel.

[0041] In one alternative embodiment of this implementation, the coil body 10 is 3D printed, and each helical segment 11 has different geometric parameters from each other, which are selected from at least one of helical radius, helical helix angle, and axial pitch.

[0042] In this embodiment, the geometric parameters of each helical segment 11 can be adjusted according to actual needs, so that the axes of each coil layer can be completely coincident, ensuring the coaxiality of each coil layer. In this way, the magnetic field energy of each coil layer is precisely superimposed on the common axis, multiplying the magnetic field strength and greatly increasing the heating power of the metal rod. At the same time, multiple coil layers form a highly uniform magnetic field region near the common axis, making the heating of the metal rod more uniform along its axial direction.

[0043] In this embodiment, by adjusting the geometric parameters of each spiral segment 11, the roundness and symmetry of each coil layer can be ensured. This not only ensures the uniformity and stability of the magnetic field formed, but also improves the mechanical strength of the coil body 10 and extends its service life.

[0044] In one optional embodiment of this invention, the top coil layer and the bottom coil layer are in a horizontal position.

[0045] In one optional embodiment of the present invention, the coil body 10 has three coil layers.

[0046] In one optional embodiment of this utility model, the connecting pipe 30 is in the shape of a round tube.

[0047] In an optional embodiment of the present invention, the coil body 10 has transition circular tube sections 12 at both ends for connection with the connecting tube 30.

[0048] In one optional embodiment of this invention, the insulating layer is a ceramic insulating layer, which further reduces the risk of arcing in the induction coil 100.

[0049] In one optional embodiment of this utility model, both the square metal tube and the connecting tube 30 are copper tubes.

[0050] In one optional embodiment of this utility model, the coil body 10, the connecting tube 30, and the coil electrode 20 are welded together.

[0051] This utility model also relates to a method for manufacturing an induction coil, used to manufacture the induction coil 100 as described above, the method comprising:

[0052] Construct a three-dimensional model of the coil body 10, and set the 3D printing process parameters based on the three-dimensional model;

[0053] The coil body was 3D printed based on the process parameters to obtain the coil body 10;

[0054] The coil body 10, the coil electrode 20 and the two connecting tubes 30 are welded together;

[0055] A ceramic insulating coating is sprayed onto the surface of the coil body 10 and the surface of the connecting tube 30 to form a ceramic insulating layer.

[0056] The induction coil processing method proposed in this invention sets 3D printing process parameters based on a three-dimensional model, thereby controlling the helical radius, helical angle, and position of each coil layer of the coil body 10. This ensures that the coil body 10 is highly consistent with the designed three-dimensional model, guaranteeing the symmetry, uniformity, and expected gradient distribution of the magnetic field formed by the induction coil 100. Simultaneously, the coil body 10 is integrally formed by 3D printing, improving its mechanical strength and enabling it to better withstand the impact and vibration from electromagnetic forces. Furthermore, once the 3D printing process parameters are set, each coil body 10 obtained by 3D printing can maintain a high degree of consistency, achieving digitalization and customization of the coil body 10 processing.

[0057] In one optional embodiment of this utility model, each coil layer is formed by sequentially splicing multiple spiral segments 11. The 3D printing process parameters include the geometric parameters of each spiral segment 11, which include at least the helical radius, helix angle and axial pitch.

[0058] In one optional embodiment of this invention, pure copper powder with a particle size of 15-53μm is selected as the printing material for 3D printing.

[0059] In one optional embodiment of this invention, green light is selected as the light source for laser printing.

[0060] In one optional example of this implementation, the 3D printing data is set as follows: spot diameter 20-40μm, scanning speed 8m / s, printing speed 10-30cm3 / h, and layer thickness 20-120μm.

[0061] In one optional embodiment of this utility model, the coil body 10 after printing is subjected to heat treatment.

[0062] In one optional example of this implementation, the heat treatment process is as follows: annealing temperature 260-380℃, holding time 30-60 minutes, and furnace cooling.

[0063] In one optional embodiment of this invention, the coil body 10, the connecting pipe 30, and the coil electrode 20 are welded together by tungsten inert gas (TIG) welding. TIG welding has a small heat-affected zone and is protected by argon gas, which effectively prevents oxidation of the welded area and ensures its electrical conductivity.

[0064] In one optional embodiment of this utility model, the surface of the coil body 10 and the surface of the connecting tube 30 are sandblasted before spraying.

[0065] In one optional embodiment of this invention, the ceramic insulating coating comprises at least ceramic particles, flake-like nano-sized mica, alumina, and silicon nitride.

[0066] In an optional example of this embodiment, the ceramic insulating coating is a high-temperature resistant ceramic insulating coating, in which inorganic-organic graft-modified resin is re-chelated into a film-forming substance. Ceramic microparticles are the main component of the film-forming substance in the coating, and the temperature resistance can reach 600°C.

[0067] In one optional example of this implementation, sheet-like nanoscale mica, alumina, and silicon nitride are used as coating fillers.

[0068] Furthermore, fillers such as alumina and silicon nitride have high volume resistivity and a compact structure.

[0069] In one optional embodiment of this utility model, the ceramic insulating coating can be applied to the surface of the coil body 10 and the surface of the connecting tube 30 by means of air spraying, airless spraying, brushing or roller coating.

[0070] In one optional embodiment of this invention, after the ceramic insulating coating is applied, the ceramic insulating coating is dried and cured.

[0071] The detailed explanations of the above embodiments are intended only to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions should not be construed as limiting the present invention for any reason. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there is an explicit description to the contrary, these features should be understood to be applicable to any embodiment, and not limited to the described embodiments.

Claims

1. An induction coil, characterized in that, The inductive coil comprises a coil body, a coil electrode and two connecting tubes, the coil body is spirally coiled by a square metal tube, the coil body has a conical spiral structure, the coil body comprises a plurality of coil layers arranged coaxially and stacked, each coil layer is composed of a plurality of spiral line segments, the two ends of the coil body are fixedly connected with the coil electrode through the two connecting tubes respectively, and the outer wall of the square metal tube and the outer wall of the connecting tube are covered with an insulating layer.

2. The induction coil of claim 1, wherein, The plurality of coil layers are stacked in the axial direction, the outer sidewall of each coil layer jointly forms a first conical surface, and the inner sidewall of each coil layer jointly forms a second conical surface.

3. The induction coil of claim 2, wherein, The first conical surface is parallel to the second conical surface.

4. The induction coil of claim 3, wherein, The top angle of the first conical surface and the second conical surface ranges from 40 to 70 degrees.

5. The induction coil of claim 1, wherein, Each coil layer comprises three spiral line segments.

6. The induction coil of claim 5, wherein, Taking the starting point of each turn as 0 turns, the three spiral line segments are a first spiral line segment of 0 turns to less than 0.2 turns, a second spiral line segment of more than 0.2 turns to less than 0.9 turns, and a third spiral line segment of more than 0.9 turns to 1 turn.

7. The induction coil of claim 6, wherein, The coil body comprises an uppermost coil layer, a second coil layer and a lowermost coil layer arranged in sequence from top to bottom; in the second coil layer and the lowermost coil layer, the pitch of the first spiral line segment and the pitch of the third spiral line segment are 1.6P±0.3P, and the pitch of the second spiral line segment is P; in the uppermost coil layer, the pitch of the first spiral line segment is 1.6P±0.3P, the pitch of the first spiral line segment is 0.6P±0.2P, and the pitch of the first spiral line segment is 0.4P±0.2P; wherein P is a preset reference pitch.

8. The induction coil of claim 1, wherein, The coil body is formed by 3D printing, each spiral line segment has different geometric parameters from each other, and the geometric parameters are selected from at least one of a spiral radius, a spiral angle and an axial pitch.

9. The induction coil of claim 1, wherein, The insulating layer is a ceramic insulating layer.

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