JP5842183B2 - Induction heating device - Google Patents

Description

  The present invention relates to an induction heating device that brazes metal pipes together.

  A heat exchanger used for an air conditioner or the like is brazed to a connection between metal pipes. As a method for performing this brazing, a method using induction heating as disclosed in Patent Document 1 has been proposed. The state of induction heating of the heat exchanger in Patent Document 1 is shown in FIG.

  The heat exchanger includes a large number of plate fins 7 made of aluminum or the like arranged in parallel, a protective iron plate 8 arranged in parallel to the plate fins 7 at the boundary between the plate fins 7 and the outside, and these A metal pipe called a plurality of tubes 6a made of copper or the like disposed so as to penetrate the plate fin 7 and the iron plate 8 in the thickness direction, and a plurality of U-shaped or other shapes connecting the plurality of tubes 6a. It is formed of a metal pipe called a metal joint pipe 6b. At this time, the tube 6a and the joint pipe 6b are joined so that the refrigerant circulates in the tube 6a. As this joining method, brazing is mainly used.

  The heating coil 1 is bent in a U shape in a plan view and an inverted U shape in a side view, and uses a gap between the U-shaped portions in the plan view of the heating coil 1 as a heating part space. The heated body 6 includes a tube 6a and a joint pipe 6b, and a ring wax 6c fitted to an overlapping portion of the tube 6a and the joint pipe 6b. Brazing is performed by performing induction heating in a state where the object to be heated 6 is disposed in the heating space of the heating coil 1.

  However, when induction heating is used for brazing of the heat exchanger, there is a problem that parts other than the heated object 6 are heated. In particular, the heating of the iron plate 8 that is close to the heated body 6 is significant, and quality defects such as burning of the iron plate 8 may occur.

  This is because the magnetic flux generated from the coil leaks to other than the heated body 6 and induction heats the metal other than the heated body 6.

  Conventionally, a method using a magnetic core 19 as disclosed in Patent Document 2 has been proposed as a method for suppressing leakage magnetic flux. The state of induction heating in Patent Document 2 is shown in FIG. The heating coil 1 is formed so as to be wound around the magnetic core 19. The metal pipe 18 is induction-heated by causing a current to flow through the heating coil 1 to generate a magnetic flux 10. Here, the magnetic core 19 is made of a material having a higher magnetic permeability than air and easily concentrates the magnetic flux. Accordingly, when a current is passed through the heating coil 1 to generate the magnetic flux 10, the magnetic flux 10 is concentrated on the magnetic core 19. By concentrating the magnetic flux 10 on the magnetic core 19 in this way, the leakage magnetic flux to the outside is suppressed.

JP H10-216930 Japanese Patent No. 4155577

  However, in the configuration using the magnetic core as described in Document 2, the magnetic core is exposed to a cycle of heating and cooling in the heating process, and the magnetic core is damaged or deteriorated. Many of the ferromagnetic materials used for the magnetic core have a heat-resistant temperature of 500 ° C. or less. When heated to a temperature higher than this, the material may be physically damaged or the magnetic properties may be deteriorated. Brazing is often performed at a temperature exceeding 500 degrees, and the magnetic core is also heated to a temperature close thereto. Therefore, when a magnetic core is used for induction heating brazing, the magnetic core is easily damaged or deteriorated.

  In such high temperature induction heating, the magnetic core becomes a consumable item, and there is a problem that it takes time and cost for replacement.

  The present invention solves the above-described problems, and an object thereof is to provide an induction heating apparatus that can reduce the labor and cost of replacing parts.

  In order to achieve the above object, the induction heating apparatus of the present invention is configured as follows.

According to one aspect of the present invention, a metal pipe-shaped object to be heated disposed in the vicinity of the metal body is disposed in a gap in the intermediate portion, and the object to be heated is induced by electric power supplied from an induction heating power source. An induction heating coil for heating;
The central axis is parallel to the central axis of the heating coil, and the magnetic flux is generated in the opposite direction to the magnetic flux generated by the heating coil except for the intermediate portion, and the same magnetic flux as the heating coil generates at the intermediate portion. An induction heating device is provided that includes an auxiliary coil arranged to generate a magnetic flux parallel to a direction .

  As described above, according to the induction heating device of the present invention, by providing the auxiliary coil arranged so that the magnetic flux is generated in the direction opposite to the magnetic flux generated by the heating coil, the object to be heated without using the magnetic core. Heating of other metals can be suppressed, and the labor and cost of replacing parts can be reduced.

The schematic perspective view of the induction heating apparatus in embodiment of this invention The figure of distribution of typical magnetic flux which each of a heating coil and an auxiliary coil generates in a top view of an induction heating device of an embodiment of the present invention. The figure of the direction of the magnetic flux which each of a heating coil and an auxiliary | assistant coil mainly produces | generates on the iron plate in the right view of the induction heating apparatus of embodiment of this invention. Diagram showing definition of coil dimensions in analysis Diagram showing the definition of angle between coils in analysis A graph showing the relationship between the distance between the axes of the heating coil and auxiliary coil and the temperature of the iron plate A graph showing the relationship between the angle between the coils and the temperature of the iron plate Graph showing the relationship between the auxiliary coil width and the iron plate temperature A graph showing the relationship between the number of turns of the auxiliary coil and the temperature of the iron plate The schematic perspective view of the induction heating apparatus using the series coil in embodiment of this invention Schematic configuration diagram of a conventional induction heating device Schematic configuration diagram of an induction heating device using a conventional magnetic core

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, the induction heating apparatus 30 which is embodiment of this invention is shown.

  The induction heating device 30 includes a heating coil 1, an auxiliary coil 2, and an induction heating power source 4. Two induction heating power sources 4 are prepared for the first induction heating power source 4A for the heating coil 1 and the second induction heating power source 4B for the auxiliary coil 2.

  A heat exchanger as an example of an object having an object to be heated 6 heated by the induction heating device 30 includes the object to be heated 6, plate fins 7, and a protective iron plate 8.

  The plate fin 7 and the iron plate 8 are parallel to each other, and the iron plate 8 is disposed on the uppermost surface of the plate fin 7. The iron plate 8 is an example of a metal body.

  The heated body 6 includes a tube 6a, a joint pipe 6b, and a ring solder 6c arranged on the overlapping portion thereof, and is an example of a heated body having a metal pipe shape. The tubes 6a are arranged so as to pierce perpendicularly to the plate fins 7 and the iron plate 8. The joint pipe 6b connects the tubes 6a to each other, but the connecting portion is omitted in the drawing.

  The first induction heating power source 4A supplies power to the heating coil 1 via the cable 5a.

  Another second induction heating power source 4B supplies power to the auxiliary coil 2 via the cable 5b. At this time, the phases of the currents of the two first and second induction heating power supplies 4A and 4B are set to coincide with each other.

  The heating coil 1 is provided with a gap 1a so that the heated body 6 can be installed in the middle part of the solenoid coil. The heating coil 1 is arranged so that the heated object 6 is inserted into the gap 1 a in the middle part of the heating coil 1.

  The auxiliary coil 2 is a solenoid coil. The auxiliary coil 2 is arranged so that the central axis 2b of the auxiliary coil 2 and the central axis 1b of the heating coil 1 are parallel to each other. Further, the auxiliary coil 2 is arranged so as to generate a magnetic flux 11 in a direction opposite to the direction of the magnetic flux 10 generated by the heating coil 1. The auxiliary coil 2 can use the same member as the heating coil 1.

  The induction heating device 30 configured as described above operates as follows.

  First, the heating coil 1 is arranged so that the heated body 6 is positioned in the gap 1 a in the intermediate portion of the heating coil 1.

  Thereafter, the two first and second induction heating power supplies 4A and 4B are energized, and a high-frequency current is energized through the heating coil 1 and the auxiliary coil 2.

  By energizing each of the heating coil 1 and the auxiliary coil 2, magnetic fluxes 10 and 11 are generated from the coils 1 and 2, respectively. By these magnetic fluxes 10 and 11, the heated body 6 is induction-heated. When the temperature of the heated body 6 exceeds the melting point of the brazing material of the ring solder 6c, the ring solder 6c is melted.

  After the ring wax 6c is melted, the energization of the two first and second induction heating power sources 4A and 4B is stopped.

  Thereafter, the ring wax 6c is cooled, so that the ring wax 6c is solidified, and the tube 6a and the joint pipe 6b constituting the heated body 6 are joined.

  The auxiliary coil 2 has an action of canceling out the magnetic flux leaking from the heating coil 1 to other than the heated body 6. This will be described below.

  FIG. 2A shows an example of typical magnetic fluxes 10 and 11 among the magnetic fluxes 10 and 11 generated by both the heating coil 1 and the auxiliary coil 2. An arrow indicated by a thick dotted line represents the current 9. When this current 9 flows through the heating coil 1 and the auxiliary coil 2, a representative magnetic flux 10 among the magnetic fluxes generated by the heating coil 1 is indicated by a bold line, and among the magnetic fluxes generated by the auxiliary coil 2, A representative magnetic flux 11 is indicated by a thin line.

  Attention is paid to the distribution of the magnetic flux 10 generated by the heating coil 1 and the magnetic flux 11 generated by the auxiliary coil 2. Looking at the outside of the heating coil 1 and the auxiliary coil 2, it can be seen that the magnetic flux 10 generated by the heating coil 1 and the magnetic flux 11 generated by the auxiliary coil 2 are in opposite directions (for example, the following figure). (See on 2B iron plate 8). From this, it can be seen that outside the heating coil 1 and the auxiliary coil 2, the magnetic fluxes 10 and 11 are weakened each other. In order to confirm the magnetic flux distribution in the vicinity of the iron plate 8, the magnetic flux distribution in the right side view of FIG. 2A is shown in FIG. 2B. Even in the vicinity of the iron plate 8, it can be seen that the magnetic flux 10 generated by the heating coil 1 and the magnetic flux 11 generated by the auxiliary coil 2 are in opposite directions and weaken each other. Note that in both FIGS. 2A and 2B, the heated object is omitted for easy understanding of the magnetic flux distributed in the space.

  As described above, by using the auxiliary coil 2, it is possible to suppress the leakage magnetic flux to other than the heated body 6 and suppress the heating of the iron plate 8 without using the magnetic core.

  Here, the shape and arrangement of the auxiliary coil 2 will be described.

  With respect to the shape and arrangement of the auxiliary coil 2, better conditions were derived using analysis. Analysis simulation software Femet (registered trademark) (ver. 11.1) (Murata Software Co., Ltd.) is used for the analysis.

  The analysis model used in the analysis is shown.

  The analysis model was configured to be equivalent to FIG. However, since the temperature of the iron plate 8 is a problem, the analysis is performed excluding the heated body 6 and the plate fins 7. The influence of the burning of the iron plate 8 is significant immediately below the gap 1a in the middle part of the heating coil 1. Therefore, the temperature of the iron plate 8 in this part is analyzed.

  The shape and arrangement of the heating coil 1 and the auxiliary coil 2 used in the analysis will be described with reference to FIGS. 3A and 3B.

FIG. 3A is a plan view of the induction heating device 30 shown in FIG. Here, the width of the heating coil 1 in W _1, the width of the auxiliary coil 2 shown in W _2, the coil diameter of the heating coil 1 shown in D _1, shows a coil diameter of the auxiliary coil 2 in D _2, coil The distance between 1 and 2 is indicated by L, the diameter of the wire of the heating coil ₁ is indicated by d1, and the diameter of the wire of the auxiliary coil ₂ is indicated by d2. The width W ₁ of the heating coil 1 represents the width of the heating coil 1 which includes also the wire of the coil 1, a width of 26mm as an example. The width W ₂ of the auxiliary coil 2 represents the width of the auxiliary coil 2 including also the wire of the coil 2, a width of 16mm as an example. Coil diameter D ₁ of the heating coil 1 of the solenoid constituting the heating coil 1, the dimension of inclusive diameter also coil wire, a diameter of 16mm, for example. Coil diameter D ₂ of the auxiliary coil 2, the solenoid constituting the auxiliary coil 2, the dimension of inclusive diameter also coil wire, a diameter of 16mm, for example. The distance L between the coils 1 and 2 is a distance between the central axis 1b of the heating coil 1 and the central axis 2b of the auxiliary coil 2, and the distance is 17 mm as an example. The diameter _{d 1} of the wire of the heating coil 1 is 2mm, for example. The diameter _{d 2} of the wire of the auxiliary coil 2 is 2mm, for example. The heating coil 1 is disposed so that the heated object 6 is positioned in the gap 1a at the intermediate portion. As an example, the heating coil 1 is formed by winding three coils on both sides of the heated body 6, for a total of six coils. The number of turns of the auxiliary coil 2 is 6 as an example.

  As an example, the angle formed between the straight axis 31 perpendicular to the central axis 1b of the heating coil 1 and the central axis 2b of the auxiliary coil 2 and the central axis 32 of the tube 6a is the angle θ between the coils 1 and 2. It is defined as FIG. 3B is a right side view of the induction heating device 30 shown in FIG. 1, and the angle shown here is an angle θ formed by the coils 1 and 2. In the analysis, the angle θ is set to 90 degrees.

  As an example, the iron plate 8 has a long side of 500 × a short side of 150 × a thickness of 1 mm, and the distance between the central axis 1b of the heating coil 1 and the iron plate 8 is 15 mm.

  As an example, the current supplied independently from the first and second induction heating power sources 4A and 4B to the heating coil 1 and the auxiliary coil 2 is 400A, and the phases of both are set to be constant.

  As an example, the material of the iron plate 8 is iron plated with tin, and when the temperature rises above 400 ° C., charring occurs. Therefore, it can be said that the condition that the temperature of the iron plate 8 is 400 degrees or less is a preferable condition. Moreover, it is more preferable that the temperature of the iron plate 8 is 300 degrees or less in view of a margin during heating. Therefore, the temperature of the iron plate 8 when the parameter in the analysis model is changed is examined, and the condition of the auxiliary coil 2 at which the temperature is 400 degrees or less and 300 degrees or less is derived.

There are four parameters used in the analysis. The distance L between the heating coil 1 and the auxiliary coil 2, the angle θ formed between the coils 1 and 2, the auxiliary coil width W _1, and the auxiliary coil 2, respectively. And the number of turns. Each of these parameters was analyzed and the optimum point of the auxiliary coil 2 was derived.

  First, the result of having analyzed the relationship between the distance L between the coils of the heating coil 1 and the auxiliary coil 2 and the temperature of the iron plate 8 is shown in FIG.

  From FIG. 4, it can be seen that the temperature L of the iron plate 8 is 400 degrees or less because the distance L between the heating coil 1 and the auxiliary coil 2 is 25 mm or less. Moreover, the temperature of the iron plate 8 becomes 300 degrees or less when the distance L between the heating coil 1 and the auxiliary coil 2 is 18 mm or less. Further, in order to prevent the heating coil 1 and the auxiliary coil 2 from contacting each other, the distance L between the heating coil 1 and the auxiliary coil 2 is made larger than 16 mm.

  From the above, the distance L between the heating coil 1 and the auxiliary coil 2 is preferably 25 mm or less and larger than 16 mm, more preferably 18 mm or less and larger than 16 mm.

  Next, the result of analyzing the relationship between the angle θ between the coils and the temperature of the iron plate 8 is shown in FIG.

  From FIG. 5, it can be seen that the temperature θ of the iron plate 8 is 400 degrees or less because the angle θ is 70 degrees or more. Moreover, the temperature of the iron plate 8 becomes 300 degrees or less when the angle θ is 85 degrees or more. In order to prevent the auxiliary coil 2 and the iron plate 8 from contacting each other, the angle θ between the coils is set to 90 degrees or less.

  From the above, the angle θ formed by the coils is preferably 70 degrees or more and 90 degrees or less, and more preferably 85 degrees or more and 90 degrees or less.

And the width W ₂ of the auxiliary coils, Figure 6 shows the result of analyzing the temperature of the relationship between iron plate portion 8.

From FIG. 6, it can be seen that the temperature of the iron plate 8 is 400 degrees or less because the width W ₂ is 30 mm or less. Further, the temperature of the iron plate 8 becomes 300 degrees or less, the width _{W 2} is when the 22mm or less. The width W ₂ of the auxiliary coil 2, have to be greater than the width when wound auxiliary coil 2 sufficiently dense, a specific example of this embodiment, the diameter of the wire of the auxiliary coil 2 d ₂ Is 2 mm, and the number of turns of the coil is 6. Therefore, when the auxiliary coil 2 is wound sufficiently densely, the width of the auxiliary coil 2 is 12 mm.

From the above, the width _{W 2} of the auxiliary coil is preferably greater than or less and 12mm 30 mm, and more preferably greater than 12mm at 22mm or less.

  Finally, the result of analyzing the relationship between the number of turns of the auxiliary coil 2 and the temperature of the iron plate 8 is shown in FIG.

  From FIG. 7, it can be seen that the temperature of the iron plate 8 is 400 degrees or less because the number of turns is 5 or more and 21 or less. The temperature of the iron plate 8 is 300 degrees or less when the number of turns is 6 or more and 20 or less. Calculated from the fact that the number of turns of the heating coil 1 is 6, the number of turns of the auxiliary coil 2 is preferably 0.85 to 3.5 times the number of turns of the heating coil 1, and preferably 1 to 3.3. It turns out that it is more preferable that it is below the double.

  According to such a configuration, in addition to the heating coil 1, by installing the auxiliary coil 2 arranged so that the magnetic flux 11 is generated in the opposite direction to the magnetic flux 10 generated by the heating coil 1, it is possible to provide no magnetic core. , Leakage magnetic flux can be suppressed. This eliminates the need for a consumable magnetic core, thereby reducing the labor and cost of replacing members.

  The heating coil 1 and the auxiliary coil 2 may be connected in series. Hereinafter, a coil in which the heating coil 1 and the auxiliary coil 2 are connected in series is referred to as a series coil 3. In FIG. 8, the schematic of the induction heating apparatus 30B using the series coil 3 is shown.

  The induction heating device 30B includes a series coil 3 in which the heating coil 1 and the auxiliary coil 2 are connected in series, and a single induction heating power source 4. The heat exchanger is composed of a heated body 6, a plate fin 7 and an iron plate 8.

  The heat exchanger as an example of the object having the heated body 6 heated by the induction heating device 30B is the same as that described above.

  The series coil 3 is configured by connecting the heating coil 1 and the auxiliary coil 2 in series. In addition, about the shape and arrangement | positioning of the heating coil 1 and the auxiliary coil 2, it is as above-mentioned.

The induction heating power source 4 is connected to the end of the series coil 3 via the cable 5 and supplies high-frequency induction power to the series coil 3. The induction heating device 30B having the above-described configuration operates as follows.

  First, the series coil 3 is disposed so that the heated body 6 is positioned in the gap 1 a in the middle portion of the heating coil 1.

  Thereafter, the induction heating power source 4 is energized, and the series coil 3 is energized.

  The high-frequency current generates magnetic fluxes 10 and 11 in the heating coil 1 and the auxiliary coil 2 of the series coil 3, respectively. Thereafter, the same operation as described above is performed. The auxiliary coil 2 has the effect of canceling out the magnetic flux 10 generated by the heating coil 1. The heated body 6 is induction-heated by the magnetic flux 10 generated by the heating coil 1. As a result, the ring wax 6c is melted and cooled, so that the tube 6a and the joint pipe 6b constituting the heated body 6 are joined.

  In the configuration in which power is supplied from separate power sources 4A and 4B to the heating coil 1 and the auxiliary coil 2 as shown in FIG. 1, two induction heating power sources 4A and 4B are required, which increases the cost of the equipment. There was a problem that. Moreover, it was necessary to perform control so that the two induction heating power supplies 4A and 4B have the same phase.

  According to such a configuration, the induction heating power source 4 can be made one by connecting the heating coil 1 and the auxiliary coil 2 in series, and the problem of equipment cost and the problem of control can be solved. Further, similarly to the configuration shown in FIG. 1, the leakage magnetic flux can be suppressed without providing a magnetic core, thereby reducing the labor and cost of replacing parts.

  In addition, it can be made to show the effect which each has by combining arbitrary embodiment or modification of the said various embodiment or modification suitably.

  INDUSTRIAL APPLICABILITY The induction heating device of the present invention has an effect of reducing the labor and cost of parts replacement and can be applied to brazing metal pipes of heat exchangers used for air conditioners and the like. The induction heating apparatus of the present invention can also be applied to metal pipe heating applications such as quenching of metal pipes.

DESCRIPTION OF SYMBOLS 1 Heating coil 2 Auxiliary coil 3 Series coil 4, 4A, 4B Induction heating power supply 5, 5a, 5b Cable 6 Heated object 6a Tube 6b Joint pipe 6c Ring row 7 Plate fin 8 Iron plate 9 Current 10 Magnetic flux 11 generated by heating coil 11 Magnetic flux generated by the auxiliary coil 18 Metal pipe 19 Magnetic core 30 Induction heating device 31 Straight line perpendicular to the central axis of the heating coil and the central axis of the auxiliary coil 32 Central axis of the tube D ₁ Coil diameter D of the heating coil ₂ Coil diameter of auxiliary coil L Distance between coils W ₁ Width of heating coil W ₂ Width of auxiliary coil θ Angle formed between coils d ₁ Diameter of wire of heating coil d ₂ Diameter of wire of auxiliary coil

Claims (6)

An induction heating coil for inductively heating the object to be heated by electric power supplied from an induction heating power source by arranging a metal pipe-shaped object to be heated arranged in the vicinity of the metal body in a gap in the middle part;
The central axis is parallel to the central axis of the heating coil, and the magnetic flux is generated in the opposite direction to the magnetic flux generated by the heating coil except for the intermediate portion, and the same magnetic flux as the heating coil generates at the intermediate portion. An induction heating device comprising: an auxiliary coil arranged to generate a magnetic flux parallel to a direction .   The induction heating apparatus according to claim 1, wherein a distance between the central axis of the induction heating coil and the central axis of the auxiliary coil is 25 mm or less and larger than 16 mm.   The angle formed by the straight axis perpendicular to the central axis of the induction heating coil and the central axis of the auxiliary coil and the central axis of the heated body is 70 degrees or more and 90 degrees or less. 2. The induction heating device according to 2.   The induction heating apparatus according to any one of claims 1 to 3, wherein a coil width of the auxiliary coil is 30 mm or less and greater than 12 mm.   The induction heating device according to any one of claims 1 to 4, wherein the number of turns of the auxiliary coil is not less than 0.85 times and not more than 3.5 turns of the number of turns of the heating coil.   The induction heating device according to any one of claims 1 to 5, wherein the heating coil and the auxiliary coil are connected in series to supply electric power from one induction heating power source.

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