Electromagnetic induction coil, device and heating smoking set

Abstract

The utility model provides an electromagnetic induction coil, a device and a heating smoking set, comprising at least two Litz leads which are arranged side by side and have insulated surfaces, the Litz leads spirally extend and are wound into a multi-turn coil, and an accommodating cavity is formed in the coil along the extending direction; the first end of the coil is bent and then extends to be roughly flush with the second end in the extending direction, and the electromagnetic induction coil generates an induced magnetic field to heat the smoke cartridge in the power-on state. A circuit system can capture and process feedback signals conveniently, the diameter, the number of strands, the number of layers and the number of turns of an optimized electric conductor are flexibly set, a multi-turn coil with appropriate inductance and quality factors is wound, the skin effect and the proximity effect under high-frequency application are reduced, and the multi-turn coil has the advantages of being low in loss and high in reliability. The method is suitable for preparing an aerosol generating system with high working efficiency.

Description

Technical Field

[0001] This utility model relates to the field of heated non-combustible tobacco technology, specifically to an electromagnetic induction coil, a device, and a heated tobacco appliance. Background Technology

[0002] Traditional electronic cigarette heating methods mostly use resistance wire heating, which suffers from slow heating speed, low efficiency, and a tendency to dry-burn. Electromagnetic induction heating technology holds promise for solving these problems. Its basic working principle is to use a high-frequency alternating magnetic field to generate eddy currents inside a conductor, thereby achieving heating. However, with the continuous development of electronic cigarette technology, the requirements for heating efficiency and flavor are becoming increasingly stringent.

[0003] An electromagnetic induction heating system forms an inductor coil by winding a conductor material around the outside of the heating cavity. An alternating current is generated by an electronic control system. The alternating current passes through the coil and generates an alternating magnetic field. Due to hysteresis loss and eddy current effect, heat is generated in the conductor or magnetic sensor located in the magnetic field. The conductor or magnetic sensor can be placed inside or outside the cigarette. The heat generated therein is used to bake and heat the smoking material in the cigarette, so that it produces an aerosol that can be inhaled.

[0004] Existing electromagnetic induction coils mostly use single-strand coils, which suffer from problems such as significant skin effect, excessive inductance, and low quality factor, resulting in low heating efficiency, high energy loss, and poor taste. Therefore, it is particularly necessary to propose a new type of electromagnetic induction coil. Utility Model Content

[0005] To address the aforementioned problems in the prior art, this invention provides an electromagnetic induction coil. It comprises at least two side-by-side insulated Litz wires, spirally wound into a multi-turn coil, with a receiving cavity formed within the multi-turn coil along its extension direction; the first end of the multi-turn coil is bent and extends along its extension direction to approximately flush with the second end.

[0006] Furthermore, the conductor is a circular wire with a diameter ranging from 0.05 to 3 mm.

[0007] Furthermore, the conductors extend parallel to each other along the length in a single layer, or in multiple layers arranged vertically to each other in parallel along the length.

[0008] Furthermore, a single conductor is formed by twisting together multiple electrical conductors.

[0009] Furthermore, the cross-section of a multi-turn coil is a type of planar geometry.

[0010] An electromagnetic induction device is provided. It includes the aforementioned electromagnetic induction coil and a base made of an insulator. The base is disposed in a cavity containing the multi-turn coil for receiving a smoke cartridge, and the electromagnetic induction coil is wound around the periphery of the base.

[0011] Furthermore, the base is positioned at the two wire connectors at the second end of the multi-turn coil.

[0012] Furthermore, a heat insulation layer is provided between the electromagnetic induction coil and the base.

[0013] An electromagnetic induction heating smoking device is provided. It includes the aforementioned electromagnetic induction coil and a power supply circuit that provides alternating current to the electromagnetic induction coil. When energized, the electromagnetic induction coil generates an induced magnetic field to heat the smoking cartridge.

[0014] Furthermore, the power supply circuit uses a Class E or Class F power amplifier to generate high-frequency resonance, with an operating frequency in the range of 1-10MHz.

[0015] Compared with existing technologies, the beneficial effects of this utility model are as follows: The electromagnetic induction coil disclosed in this application, with its internal structure consisting of regularly arranged Litz wires, reduces the skin effect and proximity effect in high-frequency applications. When using, for example, a Class E or Class F power amplifier, it operates stably within a frequency range of 1-10MHz, offering advantages such as rapid heating, high energy utilization, and compact structure. Based on the concept of this solution, it facilitates the capture and processing of feedback signals in the circuit system, allowing for flexible and optimized settings of the conductor diameter, number of strands, number of layers, and number of turns. This enables the winding of multi-turn coils with suitable inductance and quality factor, exhibiting low loss and high reliability, making it suitable for manufacturing highly efficient aerosol generation systems (electromagnetic heating devices and cartridges). Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a wound electromagnetic induction coil.

[0017] Figure 2 This is a simulation diagram of the magnetic field effect in Example 1.

[0018] Figure 3 This is a cross-section of the planar geometry of different types of coils in Example 2.

[0019] Figure 4 This is a schematic diagram of the base structure.

[0020] Figure 5 This is a cross-sectional schematic diagram of different conductor arrangement methods in Example 3.

[0021] Figure 6 This is a cross-sectional schematic diagram of the conductor arrangement in Example 4.

[0022] Figure 7This is a schematic diagram of the internal twisting method of the wire in Example 4. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] Example 1

[0025] like Figure 1 As shown, the electromagnetic induction coil 10 includes four insulated wires 101 arranged side by side. An example is shown of adjacent first wires 1011 and second wires 1012, both of which are enameled wires. The side-by-side wires are spirally wound into a multi-turn coil, with a receiving cavity formed within the multi-turn coil along its extension direction. "Turn" is a term referring to the number of turns, combined with... Figure 1 Then it is 4 turns.

[0026] For example, parallel-arranged wires can be ribbon cables or enameled wires.

[0027] The first end of the multi-turn coil (the left end in the diagram) is bent and extended along the direction of extension until it is roughly flush with the second end (the right end in the diagram). "Roughly flush" is a physical description, meaning that the lengths may be identical or slightly different but fluctuating within a certain range. Figure 1 The two connectors 102 shown are of different lengths but can also be considered to be roughly flush, because an external circuit, i.e., a circuit board assembly (PCBA) in a heated smoke appliance, can be operably connected at the end connector 102. It is understood that the first end of the multi-turn coil, after being bent, extends along the extension direction to the second end, and its placement on the outside of the multi-turn coil does not affect the magnetic field distribution inside the coil. It is important to note that the present invention wraps a high-temperature resistant insulating film (not shown in the figure), such as polyimide (PI) high-temperature tape, around the main body of the coil. Firstly, as an insulating layer, this layer exists between the first end and the main body of the coil after bending, preventing short circuits caused by the rupture of the protective film of the enameled wire; secondly, as a fixing layer, it shapes the coil and prevents it from scattering.

[0028] For example, the connectors 102 are connected together by a tin-dip / tin-plating process, which achieves both fixation and good electrical connection performance.

[0029] In existing technologies, induction coils mostly use a single conductor. Due to the skin effect of high-frequency current, the current concentrates on the surface of the conductor, with a skin depth typically tens of micrometers, while almost no current flows through the center of the conductor. If a single conductor is used, the coil's resistance will increase to some extent, resulting in greater heat generation. Typically, in electromagnetic heating aerosol generation systems (i.e., combinations of electromagnetic heating devices and cartridges), the main heat-generating areas consist of three parts: the MOSFET on the PCBA, the magnetoresistive sensor located in the coil's magnetic field, and the coil itself. This invention aims to minimize the heat loss of the first two components, focusing the heat primarily on the magnetoresistive sensor to achieve a highly efficient aerosol generation system. The heat loss of the MOSFET can be controlled through optimized circuit design and programming, while enhancing the heating effect of the magnetoresistive sensor can be achieved through appropriate material and structural design. Therefore, this invention employs a novel design approach to reduce the heat loss of the coil itself: using Litz wire to wind the solenoid coil.

[0030] Litz wire is a conductor structure made of multiple strands of insulated fine wires twisted together according to a specific pattern. The core design of the coil wound with it in this invention is to reduce the skin effect and proximity effect in high-frequency applications by dispersing the current path, thereby reducing the resistive loss of the coil conductor at high frequencies.

[0031] This technical solution uses a composite conductor composed of multiple Litz wires, each with its own cross-section, arranged side-by-side. When a high-frequency alternating current passes through the coil, due to the skin effect, the current concentrates on the surface of the conductor. Compared to a coil using a single wire, a coil made of composite wires disperses the current, resulting in a larger effective current flow area, more uniform current distribution within the conductor's cross-section, and lower equivalent resistance. Therefore, this electromagnetic induction coil effectively reduces energy loss due to resistance. Although eddy currents (internal proximity effect) still occur between the individual strands of the Litz wire due to the alternating magnetic field, the twisting design reduces the unevenness of current distribution, resulting in lower overall loss compared to a single thick wire. Furthermore, the electromagnetic induction coil, composed of multiple conductors wound together, has gaps between each conductor, which facilitates heat dissipation.

[0032] In this application, the coil, as a crucial component of the heating system, engages in electromagnetic induction coupling with a sensor within the cartridge. On one hand, the coil generates a high-frequency alternating electromagnetic field to excite the sensor, inducing eddy current and hysteresis losses, ultimately converting the electrical energy from the power supply into heat energy within the sensor. On the other hand, as the cartridge is inserted or removed, and as the temperature changes, the sensor generates feedback signals via the coil, causing changes in one or more physical quantities within the circuit system. The system then processes these changes and, referencing multiple preset target conditions, initiates corresponding control programs. Based on these two aspects of coupling—eddy current heating and signal feedback—the functions of heating, measuring, and controlling the temperature of the sensor can be achieved.

[0033] For example, the coil is formed by multiple turns of single or multiple layers of Litz wire surrounding at least a portion of the cartridge compartment, configured as a helical tube. The Litz wire is composed of multiple strands of independently insulated electrical conductors twisted or braided together. The wire is a circular wire with a diameter in the range of 0.05-3 mm, including the outer insulation layer, and is made of common enameled wire.

[0034] For example, in order to achieve high conductivity and low resistance, and to minimize the heat generated by the coil itself, the conductor material is set to copper, silver, aluminum, gold, or an alloy mainly composed of these elements, which have very low resistivity.

[0035] For example, to wind a coil with suitable inductance and quality factor, and to facilitate the circuit system's capture and processing of feedback signals, it is necessary to optimize the diameter, number of strands, number of layers, and number of turns of the conductor. Based on practical experiments with cigarette cartridges, the number of turns, ideally not exceeding 18, is suitable for both length and heating performance. The number of turns affects the coil's inductance and impedance, which in turn affects the heating power and frequency. Generally, increasing the number of turns can increase heating power, but it also increases the coil's resistance and inductance, affecting efficiency. A tight winding method is used to minimize the turn spacing, thereby improving the coil's coupling coefficient and efficiency. The spacing between coils affects the degree of magnetic field coupling and heating uniformity. Too small a spacing may cause magnetic fields to cancel each other out, reducing heating efficiency.

[0036] Continue to refer to Figure 1 The implementation method uses COMSOL software to simulate the magnetic field distribution of the heating system at a frequency of 5MHz and an input alternating current of 2A, as shown below. Figure 2 Simulation results show that the magnetic field of the coil exhibits a roughly symmetrical distribution, with the highest magnetic flux density, reaching up to 1.57 × 10⁻⁶, occurring in the central region near the axis inside the solenoid. -3Tesla level. It can be predicted that placing a strong magnetic sensor in a high magnetic flux density region can generate strong electromagnetic induction coupling, thus producing strong eddy current heating within the sensor, which in turn acts on the aerosol generation matrix in the cartridge that is in contact with the sensor. In this aerosol generation system configuration, the sensor is located inside the cartridge, employing an internal central heating mode.

[0037] Example 2

[0038] This embodiment illustrates the use of magnetic induction coils with different cross-sectional shapes, combined with... Figure 3 The cross-section of the multi-turn coil is a planar geometric shape, such as a circle, square, hexagon, or rectangle. In feasible solutions, a planar geometric shape is selected, such as a circle, ellipse, or a regular polygon. The number of polygons ranges from 3 to 24, preferably 3 to 6 sides, and the structure is an equilateral triangle, square, regular pentagon, or regular hexagon.

[0039] Corresponding to coils with various cross-sectional areas, it also includes a base 20 that supports it, such as... Figure 4 As shown, the base 20 is made of a high-temperature resistant insulating material to form an electromagnetic induction device. The base is made of a high-frequency insulating material, such as polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), or polyimide (PI), to reduce dielectric loss. The hollow interior of the base 20 is housed within the coil's receiving cavity 201 to receive the smoke cartridge. The electromagnetic induction coil is wound around the base's periphery 202, and the two are fixed relative to each other.

[0040] For example, a strip-shaped positioning block 2021 is protruding on the outer periphery 202 of the base, and the electromagnetic induction coil is wound in the groove formed by the strip-shaped positioning blocks 2021 to prevent the coil from generating unnecessary movement during operation.

[0041] Therefore, it can be seen that the shape of the coil can change according to the cross-sectional shape of the base, presenting different states, and is suitable for smoking devices with different structures.

[0042] Preferably, the base 20 has a positioning part 203 at the two wire connectors 102 corresponding to the second end of the coil to fix the connectors 102, prevent short circuits, and facilitate subsequent interconnection and assembly with the PCBA. Possible solutions include methods such as drilling holes, slotting, and gluing. Figure 4 The diagram shows a pre-grooved design where the connector 102 is fixed inside the positioning part 203. This allows for a stable physical connection through the combined action of the positioning part 203 and the protruding strip-shaped positioning block 2021.

[0043] For example, a heat insulation layer is provided between the electromagnetic induction coil and the base. When inhaling, the cartridge is placed inside the heating element (sensor). The heating element heats the cartridge from the outside. That is, the tubular sensor is excited by the coil and heats up, thereby heating the cartridge from the outside circumferentially. In this case, the cartridge does not contain a sensor.

[0044] Furthermore, an electromagnetic induction heating smoking device is also provided, including an electromagnetic induction coil and a power supply circuit that provides alternating current to the electromagnetic induction coil. When energized, the electromagnetic induction coil generates an induced magnetic field to heat the smoking cartridge.

[0045] For example, a Class E or Class F power amplifier is used to construct a resonant circuit, which, in conjunction with a coil, forms a high-frequency electromagnetic induction heating system. In applications, the resonant frequency of the heating circuit is set in the high-frequency range of 1-10MHz to generate a strong magnetic field and achieve high operating efficiency. Using a Class E or Class F power amplifier, the theoretical operating efficiency can reach over 90%.

[0046] In high-frequency induction heating applications, the inductance L and quality factor Q of the coil system are crucial, as they affect heating efficiency and effect. The expression for calculating the quality factor is as follows:

[0047]

[0048] Where Q is the quality factor, f is the frequency, L is the inductance, and R is the coil resistance.

[0049] A higher inductance results in a stronger magnetic field, thus improving heating efficiency. Additionally, a higher inductance reduces penetration depth, concentrating heating on the surface of the sensor. A higher quality factor means lower energy loss, allowing the coil to more effectively convert electrical energy into magnetic field energy. Furthermore, a higher quality factor leads to a greater voltage amplification. The quality factor also affects the resonant frequency of the heating circuit; a higher quality factor results in a sharper resonant curve and a narrower frequency band, meaning only currents of specific frequencies can effectively pass through the circuit, thus improving heating efficiency and facilitating the tracking of load (sensor in the magnetic field) changes to perform the aforementioned functional operations. In short, a higher quality factor provides a narrower frequency band, higher voltage, and faster response speed, thereby improving heating efficiency and stability. This invention utilizes parameters such as the presence or absence of the sensor and its temperature-dependent characteristics to influence the inductance and quality factor of the coil system, ultimately mapping these changes to one or more physical quantities in the electronic circuit as input for implementing responsive operations.

[0050] The electromagnetic induction heating smoke appliance of this application has at least the following advantages:

[0051] (1) Enhanced heating efficiency: High-frequency current can generate a stronger magnetic field in the coil, thereby inducing a larger eddy current in the metal sensor in the cartridge, achieving higher heating efficiency.

[0052] (2) Improve heating speed: High-frequency resonance can quickly increase the temperature of the sensor, shorten the heating time, and reduce the user's waiting time.

[0053] (3) Achieve precise temperature control: The high-frequency resonant circuit can precisely control the temperature of the heating element through frequency adjustment and duty cycle control, ensuring the taste and quality of the smoke.

[0054] (4) Reduced size: The inductors and capacitors required by the high-frequency resonant circuit are smaller in size, which is beneficial to the lightweight and miniaturized design of electronic cigarette devices.

[0055] Example 3

[0056] This embodiment illustrates magnetic induction coils using different winding methods, such as... Figure 5 As shown, the coil wires extend parallel to each other along the length in a single layer (①), or in multiple layers (②③) arranged vertically to each other along the length.

[0057] This application discloses a compact coil for electronic cigarette applications to meet the requirements of high-frequency heating. To this end, Litz wire copper conductors are used, and under testing conditions of 1-10MHz, the initial inductance (without a sensor) is controlled within the range of 50-200nH, while maintaining a high quality factor of 20-100 to achieve efficient energy transfer. The coil material needs to have good conductivity to reduce the coil's own resistive losses and improve energy transfer efficiency. Copper is preferred in this application because it has excellent conductivity and heat dissipation properties, and is relatively inexpensive.

[0058] Litz wire is composed of multiple strands of fine insulated wire twisted and connected together, commonly enameled wire. It effectively reduces the skin effect and proximity effect under high-frequency current, improves the quality factor and efficiency of the coil, and reduces losses. Here, thicker round wire with fewer strands is used. The wire diameter affects the coil's resistance and current carrying capacity. A thicker wire diameter can reduce resistance loss but reduces the coil's flexibility. Here, the wire diameter is set in the range of 0.05-3mm, preferably in the range of 0.2-1mm, with 3-12 strands to balance coil resistance and high-frequency characteristics, thereby reducing the coil's parasitic capacitance. The regular configuration of the Litz wire ensures consistency of product performance parameters during mass production and reduces processing difficulty. This application uses a parallel stranded regular configuration, including single-layer or double-layer wiring, and bundled concentric circular wiring as options. Figure 5 The combination shown has an outer layer of insulating varnish and an inner layer of round copper wire.

[0059] Example 4

[0060] like Figure 6 As shown, a single conductor (1011, 1012) is formed by multiple electrical conductors (1011b) being twisted together in multiple steps and then shaped, and is covered with an insulator 1011a.

[0061] Cross-twisting method such as Figure 7 As shown. In this embodiment, the cross-stretched multiple conductors 1011b have obvious gaps on their surface, which helps to reduce the skin effect. On the other hand, increasing the surface area of ​​the conductors is beneficial for heat dissipation of the electromagnetic induction coil. Compared with the prior art, it has better implementation effect.

[0062] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. An electromagnetic induction coil, characterized in that, It includes at least two side-by-side Litz wires with insulated surfaces, which are spirally extended to form a multi-turn coil, with a receiving cavity formed inside the coil along the extension direction; the first end of the coil is bent and extended along the extension direction to be approximately flush with the second end.

2. The electromagnetic induction coil according to claim 1, characterized in that, The conductor is a circular wire with a diameter ranging from 0.05 to 3 mm.

3. The electromagnetic induction coil according to claim 1, characterized in that, The conductors extend parallel to each other along the length in a single layer, or in multiple layers arranged one above the other, extending parallel to each other along the length.

4. The electromagnetic induction coil according to claim 1, characterized in that, A single conductor is formed by twisting and turning multiple electrical conductors together.

5. The electromagnetic induction coil according to claim 1, characterized in that, The cross-section of a coil is a type of planar geometric shape.

6. An electromagnetic induction device, characterized in that, It includes the electromagnetic induction coil as described in any one of claims 1 to 5, and a base using an insulator, the base being disposed within the receiving cavity of the coil for receiving the smoke cartridge, and the electromagnetic induction coil being wound around the periphery of the base.

7. The electromagnetic induction device according to claim 6, characterized in that, The base is positioned at the two wire connectors at the second end of the coil.

8. The electromagnetic induction device according to claim 6, characterized in that, A heat insulation layer is provided between the electromagnetic induction coil and the base.

9. An electromagnetic induction heating smoke appliance, characterized in that, It includes an electromagnetic induction coil as described in any one of claims 1 to 5, and a power supply circuit that provides alternating current to the electromagnetic induction coil, wherein the electromagnetic induction coil generates an induced magnetic field to heat the smoke cartridge when energized.

10. The electromagnetic induction heating smoke appliance according to claim 9, characterized in that, The power supply circuit uses a Class E or Class F power amplifier to generate high-frequency resonance, with an operating frequency in the range of 1-10MHz.

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