High-frequency induction heating device
The high-frequency induction heating device uses two coils with magnetic coupling and resonators to uniformly heat the joint between tube bodies, addressing non-uniform heating issues and enhancing control and simplicity.
Patent Information
- Application Number
- JP2024065738
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-04-15
- Publication Date
- 2025-10-27
AI Technical Summary
Conventional high-frequency induction heating devices fail to uniformly heat the entire circumference of the joint between tube bodies, with insufficient heating at 0-degree and 180-degree parts.
A high-frequency induction heating device comprising two coils with surrounding portions that cover opposite halves of the joint, connected via magnetic coupling and resonators, allowing for nearly complete coverage and controlled heating through a bimodal frequency characteristic.
The device effectively heats the entire outer periphery of the joint between tube bodies, simplifying control and configuration while ensuring uniform heating.
Smart Images
Figure 2025162439000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a high-frequency induction heating device. [Background technology]
[0002] In order to join the joint between the first and second tube bodies with brazing material or solder, it has been proposed to heat the joint between the first and second tube bodies by high-frequency induction heating (for example, Patent Document 1 below). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent Publication No. 2021-5536 Summary of the Invention [Problem to be solved by the invention]
[0004] In the conventional example, a first coil is provided at a 90-degree point and a second coil is provided at a 270-degree point on the outer periphery of the joint between the first and second tube bodies, for example. This means that the 90-degree and 270-degree parts of the joint between the first and second tube bodies can be heated sufficiently, but the heating weakens as you move away from the 90-degree and 270-degree parts, and there is a possibility that the 0-degree and 180-degree parts will not be heated sufficiently. Therefore, an object of the present invention is to enable heating over substantially the entire circumference of the joint between the first and second pipe bodies. [Means for solving the problem]
[0005] To achieve this object, the high-frequency induction heating device of the present invention comprises a first coil having a first surrounding portion that covers a portion of the outer periphery of the joint between the first and second tube bodies, and a second coil having a second surrounding portion that covers another portion of the outer periphery of the joint, and is configured so that the outer periphery of the joint is substantially covered by the first and second surrounding portions, and a power source including a first resonator is connected to the first coil, a second resonator is connected to the second coil, a first magnetic coupling portion is provided in the first coil, and a second magnetic coupling portion is provided in the second coil that is magnetically coupled to the first magnetic coupling portion. Here, an example is given in which the end of the first tube and the end of the second tube are brazed together in a state in which one is inserted into the other. In addition, the high-frequency induction heating device of the present invention is configured such that the first surrounding portion of the first coil covers approximately half of the outer periphery of the joint between the first and second tube bodies, and the second surrounding portion of the second coil covers the remaining approximately half of the outer periphery of the joint between the first and second tube bodies. Furthermore, in the high-frequency induction heating device of the present invention, at least one of the first surrounding portion of the first coil and the second surrounding portion of the second coil is configured to be movable in an approaching direction and a separating direction relative to the outer periphery of the joint between the first and second tube bodies. In addition, the high-frequency induction heating device of the present invention has insulating layers provided on the outer peripheries of the first surrounding portion and first magnetic coupling portion of the first coil, and the second surrounding portion and second magnetic coupling portion of the second coil. Furthermore, in the high-frequency induction heating device of the present invention, the multi-resonant circuit composed of the first coil and the first resonator and the second coil and the second resonator exhibits a bimodal characteristic having two peaks in the frequency characteristics, and the power supply is configured to be driven at a frequency on the low-frequency slope of the low-frequency peak. [Effects of the Invention]
[0006] As described above, the high-frequency induction heating device of the present invention comprises a first coil having a first surrounding portion that covers a portion of the outer periphery of the joint between the first and second tube bodies, and a second coil having a second surrounding portion that covers another portion of the outer periphery of the joint, and is configured so that the outer periphery of the joint is substantially covered by the first and second surrounding portions, and a power supply including a first resonator is connected to the first coil, a second resonator is connected to the second coil, a first magnetic coupling portion is provided in the first coil, and a second magnetic coupling portion is provided in the second coil that is magnetically coupled to the first magnetic coupling portion. Therefore, according to the present invention, the outer periphery of the joint between the first and second tube bodies can be covered almost entirely by the first surrounding portion of the first coil and the second surrounding portion of the second coil, thereby effectively heating the outer periphery of the joint between the first and second tube bodies. Furthermore, according to the present invention, a power supply is provided only for the first coil, and power is supplied to the second coil via the first magnetic coupling portion of the first coil and the second magnetic coupling portion of the second coil, which makes it easy to control heating and also simplifies the configuration, making it easy to use as production equipment. [Brief explanation of the drawings]
[0007] [Figure 1] 1 is a perspective view of a high-frequency induction heating device according to an embodiment of the present invention; [Figure 2] 1 is a front view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 3] 1 is a perspective view of a main part of the high-frequency induction heating device of the first embodiment. [Figure 4] 1 is a perspective view of a main part of the high-frequency induction heating device of the first embodiment. [Figure 5] 1 is a perspective view of a main part of the high-frequency induction heating device of the first embodiment. [Figure 6] 1 is a front view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 7] 1 is a rear view of the main part of the high-frequency induction heating device. [Figure 8] 1 is a plan view of the main parts of the high-frequency induction heating device of the first embodiment. [Figure 9]1 is a right side view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 10] 1 is a perspective view of a main part of the high-frequency induction heating device of the first embodiment. [Figure 11] 1 is a front view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 12] 1 is a plan view of the main parts of the high-frequency induction heating device of the first embodiment. [Figure 13] 1 is a right side view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 14] 1 shows an equivalent circuit diagram of the high-frequency induction heating device. [Figure 15] 10 shows the frequency characteristics of the high-frequency induction heating device. [Figure 16] FIG. 10 is a perspective view of a high-frequency induction heating device according to another embodiment of the present invention. [Figure 17] 1 is a perspective view of a main part of the high-frequency induction heating device of the first embodiment. [Figure 18] 1 is a front view of the main part of the high-frequency induction heating device of the first embodiment. [Figure 19] 1 is a rear view of the main part of the high-frequency induction heating device. [Figure 20] 1 is a plan view of the main parts of the high-frequency induction heating device of the first embodiment. [Figure 21] 1 is a right side view of the main part of the high-frequency induction heating device of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0008] (Embodiment 1) FIG. 1 shows one embodiment of the present invention. In this embodiment, the end portions of cylindrical tubes 1 and 2 are joined together with brazing material. The tubes 1 and 2 can be made of materials such as iron, copper, aluminum, and alloys thereof. In this embodiment, the tubes 1 and 2 are made of aluminum. For example, the diameter of tube 1 is made larger than the diameter of tube 2, and the left end of tube 2 is inserted into the opening at the right end of tube 1, this part is used as the joint, and the right end of tube 1 and the left end of tube 2 are joined with brazing material. There are many types of brazing filler metals, such as silver brazing filler metal, copper brazing filler metal, copper alloy brazing filler metal, nickel brazing filler metal, and activated silver brazing filler metal, and a brazing filler metal that melts more easily than aluminum is selected. Specifically, in this embodiment, the brazing filler metal is based on an Al-Si eutectic system, which has a melting point several tens of degrees Celsius lower than that of aluminum, and the Si content is adjusted, with trace amounts of Bi, Mg, Zn, Cu, etc. added to prevent erosion between the base material and the brazing filler metal, and a brazing filler metal for aluminum with an adjusted melting point is used. In the state shown in Figure 1, a ring brazing filler has already been placed at the joint between tubes 1 and 2. This is melted by high-frequency induction heating, and flows into the gap at the joint between tube bodies 1 and 2 by capillary action.After the heating is stopped, it is solidified, and tube bodies 1 and 2 are integrated at the joint. The high frequency induction heating device includes coils 3 and 4, a resonator 5 connected to the coil 3, a power supply 6 connected to the resonator 5, and a resonator 7 connected to the coil 4. Coils 3 and 4 are configured to be able to move left and right in Figure 1, that is, in the direction toward and away from the outer periphery of the joint between tube bodies 1 and 2, but this configuration is not shown in order to avoid complicating the drawing. Furthermore, coils 3 and 4 have the same structure, and resonators 5 and 7 also have the same structure, reducing the number of different parts and striving to cut costs. As described above, the coils 3 and 4 have the same structure, so only the coil 3 will be described with reference to FIGS.
[0009] This coil 3 is made of a pipe made of a copper-based material and has a structure in which cooling water flows inside. However, since the structure for flowing this cooling water is also well known, this structure is not shown in the drawing to avoid complicating the drawing. As can be seen from FIGS. 5 to 9, one end of the coil 3 is connected to the side surface of the resonator 5, then extended horizontally, and then pulled up obliquely upward. As can be seen from FIG. 5 , the magnetic coupling portion 8 is then extended forward, and then a track-like magnetic coupling portion 8 is formed in the horizontal direction. A vertical semicircular enclosure portion 9 is formed in the downward portion from the above. A track-like magnetic coupling portion 10 is formed in the horizontal direction from the above. The magnetic coupling portion 10 is then pulled up diagonally upward, and finally extended horizontally to be connected to the resonator 5. Coil 4 is rotated 180 degrees clockwise with the right side of coil 3 in the state shown in Figure 6 as the central axis, and is also moved slightly upward vertically relative to coil 3, thereby combining coils 3 and 4 as shown in Figure 3. This state is shown in FIGS. 3, 4, and 10 to 13. As can be seen from Figure 3, the surrounding portion 9 of coil 3 and the surrounding portion 9 of coil 4 form an approximately circular surrounding portion 9, and the joint between the above-mentioned tube bodies 1 and 2 is arranged within this circular inner portion as shown in Figures 1 and 2. In other words, the surrounding portion 9 of coil 3 covers approximately half of the outer periphery of the joint between tube bodies 1 and 2, and the surrounding portion 9 of coil 4 covers approximately the remaining half of the outer periphery of the joint between tube bodies 1 and 2. In addition, in the state shown in Figures 1 and 2, the magnetic coupling portion 8 of coil 3 and the magnetic coupling portion 8 of coil 4 are in close proximity to each other in the vertical direction, and furthermore, the magnetic coupling portion 10 of coil 3 and the magnetic coupling portion 10 of coil 4 are also in close proximity to each other in the vertical direction. To create such a state, the coils 3 and 4 are configured to move toward or away from the tubes 1 and 2. In other words, when brazing the tube bodies 1 and 2, the coils 3 and 4 are brought close to the tube bodies 1 and 2, resulting in the state shown in Figures 3, 4, 10 to 13.When the brazing is completed, the coils 3 and 4 are removed horizontally from the tube bodies 1 and 2, the brazed tube bodies 1 and 2 are removed, and the next tube bodies 1 and 2 are set in place. The surrounding portions 9 of the coils 3 and 4 are close to each other on the left and right, the magnetic coupling portions 8 of the coils 3 and 4 are close to each other in the vertical direction, and the magnetic coupling portions 10 of the coils 3 and 4 are also close to each other in the vertical direction. However, the coils 3 and 4 are provided with an insulating layer such as an insulating coating or insulating tube around the entire periphery, including the surrounding portions 9, magnetic coupling portions 8 and 10, so no electrical short circuit occurs.
[0010] In this embodiment, when a high-frequency current is supplied from the power supply 6, a primary-side resonant current flows through the coil 3. When the primary-side resonant current flows through the coil 3 in this manner, a magnetic flux flows around the coil 3, and a current is induced in the coil 4, which is magnetically coupled by the magnetic coupling portion 8 and the magnetic coupling portion 10, and a secondary-side resonant current flows through the resonator 7. In such a configuration, the frequency of the high frequency current supplied from the power supply 6 to the coil 3 is important. FIG. 14 shows an equivalent circuit of a power supply 6 made up of an inverter, a resonator 5, a coil 3, a coil 4, a resonator 7, and a portion where the tubes 1 and 2 are magnetically influenced by the magnetic field created by the coils 3 and 4. In Figure 14, V1 is the AC voltage source, L0 is the current control inductance, R0 is the output impedance, LW is the equivalent coil of the part of tubes 1 and 2 that is affected by the magnetic field created by coils 3 and 4, RW is the equivalent resistance of the part of tubes 1 and 2 that is affected by the magnetic field created by coils 3 and 4, L1 is coil 3, R1 is the equivalent series resistance of coil 3, L2 is coil 4, R2 is the equivalent series resistance of coil 4, C1 is the capacitance of resonator 5, C2 is the capacitance of resonator 7, and k12 is the coupling coefficient between coils 3 and 4 (L1=L2, C1=C2). In addition, a matching inductor may be connected in parallel with C2 to achieve impedance matching. With such a circuit, the frequency characteristics will exhibit a bimodal characteristic with two peaks over a wide range of coupling coefficients, as shown in FIG. In such a state, in this embodiment, as shown in FIG. 15, the drive frequency of the power supply 6 is set to a frequency (A in FIG. 15) at the low frequency peak and low frequency slope. As a result, as shown in FIGS. 3 and 4, the current flowing through coil 3 and the current flowing through coil 4 flow in the same direction. That is, the current flowing in coil 4 is electromagnetically induced at magnetic coupling portions 8 and 10 by the magnetic flux caused by the current flowing in coil 3, and generally flows in the opposite direction to the direction shown in FIGS. However, if a reverse current flows through coil 4 in this way, the magnetic flux direction in the surrounding portion 9 of coil 4 will also be opposite to the magnetic flux direction in the surrounding portion 9 of coil 3, and induction heating of the outer periphery of the joint between tube bodies 1 and 2 by surrounding portion 9 will not be effective. Therefore, in this embodiment, as described above, the drive frequency of the power supply 6 is set to the frequency (A in FIG. 15) at the low frequency peak and low frequency slope. As a result, as shown in Figures 3 and 4, the current flowing through coil 3 (magnetic coupling portion 8, magnetic coupling portion 10, and surrounding portion 9 of coil 3) and the current flowing through coil 4 (magnetic coupling portion 8, magnetic coupling portion 10, and surrounding portion 9 of coil 4) were in the same direction.
[0011] This is particularly noteworthy in this embodiment, and as a result, induction heating of the outer periphery of the joint between the tubes 1 and 2 by the surrounding portion 9 can be carried out extremely effectively. In addition, in this embodiment, the enclosing portion 9 of coils 3 and 4 is formed to have an approximately circular shape, but an uncovered gap portion is still formed between the enclosing portion 9 of coil 3 and the enclosing portion 9 of coil 4. However, in this embodiment, as can be seen from Figures 3, 4, and 10 to 13, if the upper part is expressed as 0 degrees, the upper part (near 0 degrees) of the surrounding part 9 of coil 3 includes a part that extends upward from the upper end of the surrounding part 9 of coil 4 and then "covers the upper gap between the surrounding parts 9 of coils 3 and 4 from above." Furthermore, in this "portion of coil 4 that covers the upper gap between the enclosing portions 9 of coils 3 and 4 from above," a high-frequency current flows in the same direction as the high-frequency current flowing in the enclosing portions 9 of coils 3 and 4, as shown in Figure 3. As a result, even in the upper gap portion between the surrounding portion 9 of coil 3 and the surrounding portion 9 of coil 4, the magnetic flux generated in the "portion of coil 4 that covers the upper gap portion between the surrounding portions 9 of coils 3 and 4 from above" can heat the upper portion (near 0 degrees) of the outer periphery of the joint between tube bodies 1 and 2. On the other hand, in the lower part (near 180 degrees) of the surrounding portion 9 of coil 4, there is a part that extends downward from the lower end of the surrounding portion 9 of coil 3 and then "covers the lower gap between the surrounding portions 9 of coils 3 and 4 from below." Furthermore, in this "portion of coil 3 that covers the lower gap between the enclosing portions 9 of coils 3 and 4 from below," a high-frequency current flows in the same direction as the high-frequency current flowing in each of the enclosing portions 9 of coils 3 and 4, as shown in Figure 3. As a result, even in the lower gap between the surrounding portion 9 of coil 3 and the surrounding portion 9 of coil 4, the magnetic flux generated in the "portion of coil 3 that covers the lower gap between the surrounding portions 9 of coils 3 and 4 from below" can heat the lower portion (near 180 degrees) of the outer periphery of the joint between tube bodies 1 and 2. As a result, the entire outer periphery of the joint between the tubes 1 and 2 is effectively induction heated.
[0012] (Embodiment 2) 16 to 21 show another embodiment of the present invention. In this embodiment, a coil 4a is used. The coil 4a is different from the coil 4 in that the magnetic coupling portions 8 and 10 are spread out in the vertical direction. Therefore, the magnetic coupling portion 8a of the coil 4a is disposed above the magnetic coupling portion 8 of the coil 3, and the magnetic coupling portion 10a of the coil 4a is disposed below the magnetic coupling portion 10 of the coil 3. When such a coil 4a is used, the L component becomes large, so it is necessary to reduce the C component of the resonator 7 and adjust the resonance characteristics. Furthermore, when using a coil 4a in which the distance between the magnetic coupling portion 8a and the magnetic coupling portion 10a is widened in this manner, the distance between the magnetic coupling portion 8 and the magnetic coupling portion 10 of the coil 3 may be narrowed, and in Figures 16 to 21, the distance between the magnetic coupling portion 8 and the magnetic coupling portion 10 of the coil 3 is also slightly narrowed. In other words, the coils 3 and 4 do not need to be the same, and may be selected appropriately depending on the shapes of the tubes 1 and 2 to be heated by high-frequency induction heating. [Explanation of symbols]
[0013] 1. Body 2. Body 3 coils 4 coils 5 resonator 6 Power supply 7 resonator 8 Magnetic coupling section 9 Encirclement 10 Magnetic coupling section
Claims
1. a first coil having a first surrounding portion that covers a part of the outer periphery of the joint portion between the first and second pipes, and a second coil having a second surrounding portion that covers another part of the outer periphery of the joint portion; The first and second surrounding portions are configured to substantially cover the outer periphery of the joint portion, a power supply including a first resonator is connected to the first coil; a second resonator is connected to the second coil; A high-frequency induction heating device characterized in that the first coil is provided with a first magnetic coupling portion, and the second coil is provided with a second magnetic coupling portion that is magnetically coupled to the first magnetic coupling portion.
2. 2. The high-frequency induction heating device according to claim 1, wherein the first surrounding portion of the first coil covers approximately half of the outer periphery of the joint between the first and second tube bodies, and the second surrounding portion of the second coil covers the remaining approximately half of the outer periphery of the joint between the first and second tube bodies.
3. 3. The high-frequency induction heating device according to claim 2, wherein at least one of the first surrounding portion of the first coil and the second surrounding portion of the second coil is movable in a direction toward and away from the outer periphery of the joint between the first and second tube bodies.
4. 4. The high-frequency induction heating device according to claim 3, wherein an insulating layer is provided on the outer periphery of the first surrounding portion and the first magnetic coupling portion of the first coil, and on the outer periphery of the second surrounding portion and the second magnetic coupling portion of the second coil.
5. The multi-resonant circuit composed of the first coil, the first resonator, and the second coil, the second resonator exhibits a bimodal characteristic having two peaks in the frequency characteristics, and the power supply is configured to be driven at a frequency in the low-frequency side slope of the low-frequency side peak. The high-frequency induction heating device according to any one of claims 1 to 4.
Citation Information
Patent Citations
Induction heating apparatus and manufacturing method of heat exchanger
JP2021005536A
Cited By
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CN121198849A