Transverse type induction heating device

Abstract

Coils (230, 330) are respectively disposed front side and reverse side of a planned conveyance surface (CP). Main cores (211, 311), edge cores (212, 213, 312, 313), and bridge cores (220a, 220b, 320a, 330b) are disposed on the coils (230, 330). The bridge cores (220a, 220b, 320a, 330b) are disposed on the rear surface side of the main cores (211, 311) and the edge cores (212, 213, 312, 313). The main cores (211, 311) and the edge cores (212, 213, 312, 313) can be magnetically coupled by using the bridge cores (220a, 220b, 320a, 330b).

Description

[Technical field]

[0001] The present invention relates to a transverse induction heating device, particularly to a device suitable for use in induction heating a conductive plate to be heated by crossing an alternating magnetic field across the plate surface of the conductive plate. This application claims priority based on Japanese Patent Application No. 2021-142294 filed in Japan on September 1, 2021, the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] An induction heating device is used to continuously heat a conductive plate such as a strip-shaped steel plate. The induction heating device applies an alternating magnetic field generated by a coil to the conductive plate. Then, eddy currents are induced in the conductive plate by electromagnetic induction. The conductive plate is heated by Joule heat based on the eddy currents. An example of an induction heating device is a solenoid type induction heating device. A solenoid type induction heating device applies an alternating magnetic field approximately parallel to the longitudinal direction of a conductive plate placed inside a solenoid coil. When the thickness of the conductive plate to be heated becomes thin (for example, when the thickness of the conductive plate becomes 1 mm or less), there is a risk that the solenoid type induction heating device will not be able to heat the conductive plate to the desired temperature even if the frequency of the alternating magnetic field is increased.

[0003] As an induction heating device that can easily inductively heat a thin conductor plate, there is a transverse type induction heating device. The transverse type induction heating device includes, for example, a pair of coils arranged at least one on each of the front and back sides of the intended transport surface of the conductor plate transported in the horizontal direction. The coils constituting the pair of coils are arranged so that an alternating magnetic field generated by the passage of alternating currents in the same direction crosses the intended transport surface of the conductor plate. In a typical transverse type induction heating device, eddy currents are concentrated at the ends in the width direction of the conductor plate. Therefore, the current density at the ends in the width direction of the conductor plate increases. As a result, there is a risk that the ends in the width direction of the conductor plate will be overheated. The width direction is a direction perpendicular to the transport direction of the conductor plate and the facing direction of the coils. In the following description, the ends in the width direction of the conductor plate will be referred to as edge parts as necessary.

[0004] To address this issue, Patent Document 1 discloses a method of disposing a shield plate (shielding plate) that is movable in the width direction between the edge of the conductor plate and the magnetic pole. The shield plate is made of a non-magnetic metal material. This technology prevents the temperature distribution in the width direction of the conductor from becoming uneven by shielding the alternating magnetic field generated by the coil with the shield plate.

[0005] Patent Document 2 also discloses that a secondary coil is disposed between the edge of the conductive plate and the magnetic pole to generate a magnetic field that cancels the alternating magnetic field generated from a coil for heating the conductive plate. The technology described in Patent Document 2 prevents the temperature distribution in the width direction of the conductor from becoming uneven by generating a magnetic field from the secondary coil that cancels the alternating magnetic field generated from the coil.

[0006] Patent Document 3 also discloses forming a bulge on the original core. The bulge is disposed in a position facing the area of ​​the conductor plate where the temperature drops at both ends in the width direction. The technology described in Patent Document 3 prevents the temperature distribution in the width direction of the conductor from becoming uneven by forming a bulge on the original core.

[0007] Patent Document 4 also discloses a technique for forming a coil using a first J-shaped conductor 32 and a second J-shaped conductor 34. In the technique described in Patent Document 4, the length in the width direction of the region between the first J-shaped conductor 32 and the second J-shaped conductor 34 is changed by moving the first J-shaped conductor 32 in the width direction relative to the second J-shaped conductor 34. In the technique described in Patent Document 4, the length in the width direction of the region between the first J-shaped conductor 32 and the second J-shaped conductor 34 is changed in accordance with the width of the conductor, thereby suppressing unevenness in the temperature distribution in the width direction of the conductor.

[0008] Patent Document 5 also discloses a technique for arranging a plurality of magnetic pole segments in the width direction. In this technique, the distance between the plurality of magnetic pole segments and the conductor is changed according to the width of the conductor, thereby suppressing unevenness in the temperature distribution in the width direction of the conductor. Patent Document 5 also discloses a technique for arranging a plurality of rod-shaped magnetic poles around which a coil is wound at intervals along the conveying direction of the conductor. In this technique, the rod-shaped magnetic poles rotate around an axis that passes through the position of the center of gravity of each magnetic pole and extends in a direction perpendicular to the conductor. In this technique, the rod-shaped magnetic poles are rotated according to the width of the conductor, thereby suppressing unevenness in the temperature distribution in the width direction of the conductor. Patent Document 5 also discloses arranging a plurality of iron cores in the conveying direction of the conductor and switching the current flowing through the coil wound around the iron core. In this technique, the iron core that generates the magnetic flux is switched by switching the current flowing through the coil wound around the iron core according to the width of the conductor. In this way, this technique suppresses unevenness in the temperature distribution in the width direction of the conductor.

[0009] Patent Document 6 discloses a technology that uses multiple magnetic bars arranged in the width direction of a conductor as a core. The technology described in Patent Document 6 adjusts the spacing between multiple magnetic bars according to the width of the conductor and uses a shield plate to prevent the temperature distribution in the width direction of the conductor from becoming uneven. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Special Publication No. 63-27836 [Patent Document 2] JP 2007-122924 A [Patent Document 3] JP 2010-108605 A [Patent Document 4] U.S. Pat. No. 5,739,506 [Patent Document 5] Japanese Patent Application Publication No. 3-291891 [Patent Document 6] U.S. Patent No. 6,498,328 Summary of the Invention [Problem to be solved by the invention]

[0011] In the transverse induction heating device as described above, iron loss occurs due to the magnetic field, and the core heats up and the temperature rises. In addition, in the transverse induction heating device, a coil for heating a conductive plate is wound around the core to generate a large magnetic field. Therefore, the temperature rise of the core becomes significant. Furthermore, the heat generation of the core becomes significant in induction heating devices with a large capacity power source. In this regard, in the technology described in Patent Documents 5 and 6, the heat generation of the core is not taken into consideration, but the core is divided into multiple parts. The cross-sectional area of ​​the entire core divided into multiple parts is larger than the surface area of ​​an undivided core. The larger the surface area of ​​the core, the more heat dissipation from the core is promoted. Therefore, the heat generation of the core divided into multiple parts is suppressed compared to the heat generation of an undivided core.

[0012] When the core is divided into multiple parts in the width direction, the temperature of the core decreases. However, the alternating magnetic field in the core is divided. Therefore, when the core is divided into multiple parts in the width direction, there is a risk that an alternating magnetic field of the desired magnitude cannot be applied to the conductive plate. This reduces the heating efficiency of the conductive plate and causes a bias in the temperature distribution in the width direction of the conductive plate. The inventors have confirmed that when the core of a general transverse type induction heating device is divided into multiple parts in the width direction, the temperature of the edge part of the conductive plate may be 100°C or more lower than the temperature of the other parts of the conductive plate.

[0013] If the number of divisions of the core is reduced in order to suppress the decrease in temperature of such a conductive plate (i.e., to allow an alternating magnetic field of a desired magnitude to cross the conductive plate), the temperature of the core cannot be reduced to the desired temperature. On the other hand, if the number of divisions of the core is increased so as to reduce the temperature of the core to the desired temperature, the decrease in temperature of the conductive plate cannot be suppressed (i.e., an alternating magnetic field of a desired magnitude cannot cross the conductive plate). In the technology described in Patent Documents 5 and 6, the core is divided to suppress overheating of the edge portion and heat generation of the core. Therefore, the number of divisions of the core is determined so as to suppress overheating of the edge portion of the conductive plate and heat generation of the core. The technology described in Patent Documents 5 and 6 does not even recognize the problem of suppressing the increase in the core temperature and the decrease in the magnitude of the alternating magnetic field applied to the conductor. Thus, the conventional technology has a problem in that it is not possible to simultaneously satisfy both the suppression of the increase in the core temperature and the suppression of the decrease in the magnitude of the alternating magnetic field applied to the conductor.

[0014] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a transverse type induction heating device that can simultaneously suppress the increase in core temperature and the decrease in the magnitude of the alternating magnetic field applied to the conductor. [Means for solving the problem]

[0015] A first example of a transverse type induction heating device of the present invention includes a pair of coils arranged at least one on each of the front and back sides of a planned transport surface of a conductive plate such that an alternating magnetic field generated by the passage of alternating currents in the same direction intersects with the planned transport surface of the conductive plate, and a core arranged in a set for each coil constituting the pair of coils, wherein the set of cores arranged for each coil has a plurality of partial cores arranged with a gap between them in the width direction, the width direction being perpendicular to the transport direction of the conductive plate and the opposing direction of the coils, and each of the partial cores has a body portion and a central leg portion. The body portion extends in the conveying direction from an area upstream of the coil in the conveying direction to an area downstream of the coil in the conveying direction on the back side of the coil, the back side being opposite the side on which the intended conveying surface exists, and the central leg portion extends from the body portion in the direction of the intended conveying surface so as to pass through a hollow portion of the coil.This is a transverse type induction heating device, characterized in that the set of cores has at least one bridge core that can be magnetically coupled to at least two of the partial cores, and the bridge core is arranged on the back side of the partial cores. A second example of the transverse type induction heating device of the present invention is characterized in that each of the partial cores can be magnetically coupled to at least one of the bridge cores. A third example of the transverse type induction heating device of the present invention is characterized in that all of the partial cores included in the set of cores can be magnetically coupled via the bridge core. A fourth example of the transverse type induction heating device of the present invention is characterized in that each of the set of cores has a plurality of the bridge cores, and the bridge cores are arranged with spaces between each other in the width direction. A fifth example of the transverse type induction heating device of the present invention is characterized in that each of the set of cores has two of the bridge cores, the two bridge cores are arranged on both sides of the width direction with a gap between them, and when viewed from the opposing direction of the coil, at least a portion of each of the partial cores overlaps with one of the bridge cores. A sixth example of the transverse type induction heating device of the present invention is characterized in that the number of the bridge cores in each of the set of cores is one. A seventh example of the transverse type induction heating device of the present invention is characterized in that, in the set of cores, the partial core and the bridge core are separate cores. An eighth example of the transverse type induction heating device of the present invention is characterized in that in the set of cores, at least one of the plurality of partial cores and at least one of the bridge cores are an integral core. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 shows a first embodiment of the present invention and is a diagram illustrating an example of the external configuration of an induction heating device. [Diagram 2] FIG. 2 shows the first embodiment of the present invention and is a diagram illustrating an example of a first cross section of the induction heating device. [Diagram 3] FIG. 3 illustrates the first embodiment of the present invention and is a diagram showing an example of a second cross section of the induction heating device. [Figure 4] FIG. 4 illustrates the first embodiment of the present invention and is a diagram showing an example of a third cross section of the induction heating device. [Diagram 5] FIG. 5 shows the first embodiment of the present invention and is a diagram illustrating an example of the relationship between the position in the x-axis direction of the steel strip and the temperature. [Figure 6] FIG. 6 shows a first modified example of the first embodiment of the present invention, and is a diagram showing a first cross section of an induction heating device. [Figure 7] FIG. 7 shows a second modified example of the first embodiment of the present invention, and is a diagram showing the external configuration of an induction heating device. [Figure 8]FIG. 8 shows a second modified example of the first embodiment of the present invention, and is a diagram showing a first cross section of the induction heating device. [Figure 9] FIG. 9 shows a second embodiment of the present invention, illustrating an example of the external configuration of an induction heating device. [Figure 10] FIG. 10 shows a second embodiment of the present invention and is a diagram showing an example of a first cross section of an induction heating device. [Figure 11] FIG. 11 shows a second embodiment of the present invention, illustrating an example of a second cross section of an induction heating device. [Figure 12] FIG. 12 shows the second embodiment of the present invention and is a diagram illustrating an example of a third cross section of the induction heating device. [Figure 13] FIG. 13 shows the second embodiment of the present invention and is a diagram illustrating an example of a fourth cross section of the induction heating device. [Figure 14] FIG. 14 shows a first modified example of the second embodiment of the present invention, and is a diagram showing a first cross section of an induction heating device. [Figure 15] FIG. 15 shows a second modified example of the second embodiment of the present invention, and is a diagram showing a first cross section of an induction heating device. [Figure 16] FIG. 16 shows a third embodiment of the present invention, illustrating an example of a first cross section of an induction heating device. [Figure 17] FIG. 17 shows a third embodiment of the present invention and is a diagram illustrating an example of a second cross section of an induction heating device. [Figure 18] FIG. 18 shows an example of the external configuration of an induction heating device according to the fourth embodiment of the present invention. [Figure 19] FIG. 19 shows a fourth embodiment of the present invention and is a diagram illustrating an example of a first cross section of an induction heating device. [Figure 20] FIG. 20 shows a fourth embodiment of the present invention and is a diagram illustrating an example of a second cross section of an induction heating device. [Figure 21] FIG. 21 shows the fourth embodiment of the present invention and is a diagram illustrating an example of a third cross section of an induction heating device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, "same" includes not only the case of being strictly the same, but also the case of being different within the scope of the invention without departing from the gist of the invention. Similarly, in the following description, "match" includes not only the case of being strictly the same, but also the case of not being the same within the scope of the invention without departing from the gist of the invention. For example, in the following description, "same" includes the case of being different within the tolerance range (for example, within ±5%) determined at the time of design. In addition, in the following description, a transverse type induction heating device will be referred to as an induction heating device as necessary. In addition, in the following description, a case will be illustrated in which the conductive plate to be heated is a strip-shaped steel plate (however, the conductive plate to be heated is not limited to a strip-shaped steel plate). In addition, for convenience of notation and explanation, in each figure, some configurations are omitted or simplified. In addition, the xyz coordinates shown in each figure indicate the relationship of the orientation in each figure. A symbol with a black circle (●) in a white circle (◯) indicates a direction from the back side to the front side of the paper.

[0018] The partial cores described in the claims have various shapes, functions, and arrangement positions. For this reason, it is difficult to explain the embodiments of the present invention using only the name partial core. Therefore, in the following description of the embodiments, partial cores may be described without using the name partial core for convenience. Even in such cases, among the cores described in each embodiment, the upper core and lower core including two types of cores, partial core and bridge core, and cores with names other than bridge core are all partial cores. In each embodiment, an example of a core constituting a partial core is clearly shown in each embodiment.

[0019] (First embodiment) First, a first embodiment of the present invention will be described. FIG. 1 is a diagram showing an example of the external configuration of an induction heating device. Specifically, FIG. 1 is a diagram showing the induction heating device as viewed obliquely from above. FIG. 1 illustrates a case where the strip steel plate 100 is transported in the direction of an arrow (positive direction of the y-axis) attached to the tip of the strip steel plate 100. That is, FIG. 1 illustrates a case where the transport direction of the strip steel plate 100 is the positive direction of the y-axis. FIG. 1 also illustrates a case where the longitudinal direction of the strip steel plate 100 is the y-axis direction, the width direction of the strip steel plate 100 is the x-axis direction, and the thickness direction of the strip steel plate 100 is the z-axis direction. The thickness of the strip steel plate 100 is not limited. However, the induction heating device of each embodiment can heat a thin conductor plate. Therefore, the thickness of the strip steel plate 100 to be heated by the induction heating device of each embodiment is preferably, for example, 1 mm or less. However, the thickness of the strip steel sheet 100 to be heated by the induction heating device of each embodiment may be greater than 1 mm.

[0020] The induction heating device shown in FIG. 1 includes an upper inductor 200 and a lower inductor 300. The upper inductor 200 and the lower inductor 300 are arranged in positions facing each other through the steel strip 100 (see FIGS. 2 to 4). The upper inductor 200 and the lower inductor 300 have the same configuration. Therefore, the upper inductor 200 will be described in detail here, and a detailed description of the lower inductor 300 will be omitted as necessary. The steel strip 100 may move in the z-axis direction and the x-axis direction, and may be located slightly off-center from the center of the induction heating device. Even if the position of the steel strip 100 moves (for example, meanders), the steel strip 100 is often controlled to be located as close to the center of the induction heating device as possible by known techniques (for example, International Publication WO2019 / 181653). In the following figures including FIG. 1, the steel strip 100 is placed in an ideal position (for example, in the center of the induction heating device) where the amount of heat on the upper and lower sides of the steel strip 100 and the amount of heat on the left and right sides of the conveying direction of the steel strip 100 are equal. butA certain state is illustrated. In the following description, when the strip steel sheet 100 is in the ideal position, a plane that passes through the center position in the thickness direction of the strip steel sheet 100 and is perpendicular to the thickness direction of the strip steel sheet 100 is referred to as a conveying plane CP as necessary. The plane that passes through the center position in the thickness direction of the strip steel sheet 100 and is perpendicular to the thickness direction of the strip steel sheet 100 is also a plane that passes through the center position in the thickness direction of the strip steel sheet 100 and is parallel to the plate surface of the strip steel sheet 100. Since the conveying plane CP is determined at the time of designing the induction heating device, the conveying plane CP is inherent in the induction heating device itself. The conveying plane CP is often located at the center of the induction heating device. For this reason, the plane formed by the center of the gap between the upper inductor 200 and the lower inductor 300 may be referred to as the conveying plane CP. In the following description, the conveying direction of the strip steel sheet 100 is referred to as a conveying direction as necessary. In the following description, the direction in which the upper inductor 200 and the lower inductor 300 face each other is referred to as the facing direction of the coils or simply as the facing direction, as necessary. FIG. 1 illustrates a case in which the front side of the transport surface CP is the positive side of the z-axis, and the back side of the transport surface CP is the negative side of the z-axis. FIG. 1 also illustrates a case in which the upper inductor 200 is disposed on the front side of the transport surface CP, and the lower inductor 300 is disposed on the back side of the transport surface CP.

[0021] As described above, Fig. 1 illustrates a case where the facing direction of the coils is the z-axis direction, and the conveying direction of the steel strip 100 is the positive direction of the y-axis. Therefore, Fig. 1 illustrates a case where the width direction, which is perpendicular to the facing direction of the coils and the conveying direction of the steel strip 100, is the x-axis direction.

[0022] The distance (distance in the z-axis direction) between the upper inductor 200 and the intended transport surface CP is usually equal to the distance between the lower inductor 300 and the intended transport surface CP, but may be different. In this embodiment, the induction heating device has a shape that is in a mirror symmetric relationship with the yz plane at the center of the x-axis direction of the induction heating device as the plane of symmetry. The yz plane is a virtual plane parallel to the y-axis and z-axis. When the distance between the upper inductor 200 and the intended transport surface CP is the same as the distance between the lower inductor 300 and the intended transport surface CP, the induction heating device has a shape that is in a mirror symmetric relationship with the intended transport surface CP as the plane of symmetry.

[0023] Fig. 2 is a diagram showing an example of a first cross section of the induction heating device. Specifically, Fig. 2 is a cross section taken along line II in Fig. 1. Fig. 3 is a diagram showing an example of a second cross section of the induction heating device. Specifically, Fig. 3 is a cross section taken along line II-II in Fig. 1. Fig. 4 is a diagram showing an example of a third cross section of the induction heating device. Specifically, Fig. 4 is a cross section taken along line III-III in Fig. 1.

[0024] 2, the upper inductor 200 includes an original core 210, bridge cores 220a-220b, a coil 230, shield plates 240a-240b, cooling fins 260a-260h, and cooling tubes 270a-270h. In the following description, the width direction of the induction heating device and the strip steel plate 100 is referred to as the x-axis direction as necessary. In the following description, the direction parallel to the conveyance direction of the strip steel plate 100 (the longitudinal direction of the strip steel plate 100) is referred to as the y-axis direction as necessary. In the following description, the opposing direction of the upper inductor 200 and the lower inductor 300 (the thickness direction of the strip steel plate 100) is referred to as the z-axis direction as necessary.

[0025] The coil 230 is a conductor having a winding portion. In FIG. 1, a case is illustrated in which the thick portion (a portion other than the straight line extending from the AC power source 400) is the winding portion of the coil 230. The winding portion of the coil 230 is arranged in the xy plane so as to pass through the slots of the original core 210 and wind around the original core 210 in a racetrack shape. In this embodiment, the coils 230 and 330 are arranged to face the intended transport surface CP. The direction in which the coil 230 arranged on the front side of the intended transport surface CP and the coil 330 arranged on the back side of the intended transport surface CP face each other is the aforementioned coil facing direction. The xy plane is an imaginary plane parallel to the x-axis and y-axis. It is preferable that the coil 230 is arranged so that the direction perpendicular to the intended transport surface CP is parallel to the direction of the axis of the coil 230. The axis of the coil 230 is the axis when the coil 230 is wound. In the example shown in FIG. 1, the axis of coil 230 is parallel to the z-axis.

[0026] Incidentally, the coil 230 may have an insulator disposed around the conductor. Also, here, a case where the number of turns of the coil 230 is one is illustrated as an example. However, the number of turns of the coil 230 may be two or more. It is preferable that the number of turns of the coils 230 and 330 is the same.

[0027] 2 to 4 illustrate an example in which the end of the coil 230 on the intended transport surface CP side (the end of the coil 230 in the z-axis direction closest to the intended transport surface CP side) is closer to the intended transport surface CP than the end of the original core 210 on the intended transport surface CP side (the end of the original core 210 in the z-axis direction closest to the intended transport surface CP side). However, for example, the position in the z-axis direction of the end of the coil 230 on the intended transport surface CP side and the position in the z-axis direction of the end of the original core 210 on the intended transport surface CP side may be the same.

[0028] 2, the original core 210 has a main core 211 and edge cores 212 and 213. The main core 211 and the edge cores 212 and 213 are arranged with a gap between them in the x-axis direction. The main core 211 is a ferromagnetic material that is disposed at a position closest to the center of the induction heating device in the x-axis direction among the main core 211 and the edge cores 212 and 213. The edge cores 212 and 213 are ferromagnetic materials that are disposed closer to the end of the original core 210 in the x-axis direction than the main core 211. The edge cores 212 and 213 have a plurality of partial edge cores 212a to 212d and 213a to 213d. The plurality of partial edge cores 212a to 212d and 213a to 213d are disposed with a gap therebetween in the x-axis direction. In addition, the partial edge cores 212d and 213d that are closest to the main core 211 among the plurality of partial edge cores 212a to 212d and 213a to 213d and the main core 211 are also disposed with a gap therebetween in the x-axis direction.

[0029] Here, the state where two partial edge cores have a gap does not only mean a state where the two partial edge cores are not physically in contact with each other. For example, even if parts of two partial edge cores are in contact with each other, the two partial edge cores are not sufficiently magnetically coupled, so that the magnetic flux density in each partial edge core is lower (for example, 50% or more lower or 80% or more lower) than when a ferromagnetic material of the same material as the partial cores is present between the two partial cores. Such a state can also be regarded as a state where two partial edge cores have a gap. In other words, even in such a state, the magnetic flux density in the partial edge cores can be restored to the same level as the magnetic flux density in the main core by the bridge core described later.

[0030] In this embodiment, the main core 211 is formed of a plurality of electromagnetic steel sheets stacked in the x-axis direction, each having the same thickness and planar shape. Similarly, in this embodiment, the edge cores 212, 213 (partial edge cores 212a-212d, 213a-213d) are formed of a plurality of electromagnetic steel sheets stacked in the x-axis direction, each having the same thickness and planar shape. In addition, in this embodiment, the thickness and planar shape of the electromagnetic steel sheets that constitute the main core 211 are the same as those of the electromagnetic steel sheets that constitute the edge cores 212, 213. In addition, in this embodiment, the number of laminated electromagnetic steel sheets that constitute the main core 211 is different from the number of laminated electromagnetic steel sheets that constitute the edge cores 212, 213 (partial edge cores 212a-212d, 213a-213d). For example, if the length in the x-axis direction of main core 211 is different from the length in the x-axis direction of edge cores 212, 213 (partial edge cores 212a-212d, 213a-213d), the number of laminated electromagnetic steel sheets that make up main core 211 will differ from the number of laminated electromagnetic steel sheets that make up edge cores 212, 213 (partial edge cores 212a-212d, 213a-213d) corresponding to that difference.

[0031] The electromagnetic steel sheets constituting the main core 211 are fixed so as not to separate from each other. The electromagnetic steel sheets constituting each of the partial edge cores 212a to 212d and 213a to 213d are also fixed so as not to separate from each other. The method of fixing the electromagnetic steel sheets is not limited. For example, various known methods such as fixing with an adhesive, fixing by welding, fixing by crimping, and fixing using a fixing member are adopted as a method of fixing the electromagnetic steel sheets. The thickness and planar shape of the electromagnetic steel sheets constituting the main core 211 do not need to be the same as the thickness and planar shape of the electromagnetic steel sheets constituting the edge cores 212 and 213. For convenience of notation, the boundary lines of the individual electromagnetic steel sheets are omitted in FIG. 2. In this embodiment, a case will be illustrated in which a partial core is configured by using main cores 211, 311 and edge cores 212-213, 312-313 (a plurality of partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d).

[0032] As shown in Fig. 4, the main core 211, 311 has a body 2111, 3111, a central leg 2112, 3112, an upstream leg 2113, 3113, and a downstream leg 2114, 3114. For convenience of explanation, the body 2111, 3111, the central leg 2112, 3112, the upstream leg 2113, 3113, and the downstream leg 2114, 3114 are shown by two-dot chain lines (virtual lines) in Fig. 4 (the two-dot chain lines are virtual lines in each drawing). Fig. 4 illustrates a case where the body 2111, the central leg 2112, the upstream leg 2113, and the downstream leg 2114 are integrated. 4 illustrates an example in which the body 3111, the central leg 3112, the upstream leg 3113, and the downstream leg 3114 are also integrated together. Therefore, there is no boundary line between the body 2111, 3111, the central leg 2112, 3112, the upstream leg 2113, 3113, and the downstream leg 2114, 3114.

[0033] The trunks 2111 and 3111 are respectively provided on the rear side of the coils 230 and 330, extending in a direction parallel to the conveying direction (y-axis direction) from an area upstream of the coils 230 and 330 in the conveying direction (negative side of the y-axis) to an area downstream of the coils 230 and 330 in the conveying direction (positive side of the y-axis). The rear side of the coils 230 and 330 is the opposite side to the conveying surface CP. In the example shown in FIG. 3 and FIG. 4, the rear side of the coil 230 is the positive side of the z-axis, and the rear side of the coil 330 is the negative side of the z-axis. In the following description, the upstream side of the conveying direction is referred to as the upstream side as necessary. The downstream side of the conveying direction is referred to as the downstream side as necessary. The opposite side of the conveying surface CP is referred to as the rear side as necessary.

[0034] The central legs 2112, 3112 are extended from the trunks 2111, 3111 in the direction of the intended transport plane CP so as to pass through the hollow parts of the coils 230, 330. Here, the hollow part means the inside (not the outside) of the ring when the coils 230, 330 that go around in a racetrack shape are regarded as one ring. It is preferable that the positions of the central legs 2112, 3112 in the y-axis direction include the positions of the axial centers of the coils 230, 330 in the y-axis direction. That is, it is preferable that the y coordinates of the central legs 2112, 3112 overlap with the y coordinates of the axial centers of the coils 230, 330. In this embodiment, a case is illustrated in which the positions (xy coordinates) of the centers of gravity of the central legs 2112, 3112 in the xy plane coincide with the positions (xy coordinates) of the axial centers of the coils 230, 330 in the xy plane.

[0035] The upstream legs 2113, 3113 are provided to extend from the body parts 2111, 3111 in the direction of the intended transportation plane CP, on the upstream side (the negative direction side of the y-axis) of the coils 230, 330, respectively. The downstream legs 2114, 3114 are provided extending from the body parts 2111, 3111 in the direction of the intended transportation plane CP, downstream of the coils 230, 330 (in the positive direction of the y-axis).

[0036] The central leg 2112, the upstream leg 2113, and the downstream leg 2114 are arranged with a gap in the y-axis direction. The central leg 3112, the upstream leg 3113, and the downstream leg 3114 are also arranged with a gap in the y-axis direction. The central legs 2112, 3112, the upstream legs 2113, 3113, and the downstream legs 2114, 3114 are teeth of the core. In the main cores 211, 311, the tip surfaces of the central legs 2112, 3112, the tip surfaces of the upstream legs 2113, 3113, and the tip surfaces of the downstream legs 2114, 3114 are magnetic pole surfaces. The trunks 2111, 3111 are yokes of the core. The tip surfaces of the central legs 2112, 3112, the tip surfaces of the upstream legs 2113, 3113, and the tip surfaces of the downstream legs 2114, 3114 are surfaces that face the intended transport surface CP.

[0037] The overall outline of a cross section of the edge cores 212, 213, 312, and 313 cut along the yz plane is the same as the overall outline of a cross section of the main cores 211 and 311 cut along the yz plane. In Figure 4, (212, 213) and (312, 313) suffixed to 211 and 311 indicate this.

[0038] Therefore, the edge cores 212, 213, 312, 313 (partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d) also have a body, a central leg, an upstream leg, and a downstream leg, similar to the main cores 211, 311. The lengths in the y-axis and z-axis directions of the body, the lengths in the y-axis and z-axis directions of the central leg, the lengths in the y-axis and z-axis directions of the upstream leg, and the lengths in the y-axis and z-axis directions of the downstream leg are the same for the main cores 211, 311 and the partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d. On the other hand, the x-axis length of the body, the x-axis length of the central leg, the x-axis length of the upstream leg, and the x-axis length of the downstream leg are longer in the main cores 211 and 311 than the partial edge cores 212a-212d, 213a-213d, 312a-312d, and 313a-313d.

[0039] Moreover, the overall outer shape of the cross section of the bridge cores 220b, 320a to 320b cut along the yz plane is the same as the overall outer shape of the cross section of the bridge cores 220a, 320a cut along the yz plane (see FIG. 3). In the following description, the cross section cut along the yz plane will be referred to as the yz cross section as necessary.

[0040] As described above, the shape of the surface of the main core 211 parallel to the yz plane and the shape of the surface of the edge cores 212 and 213 parallel to the yz plane are each E-shaped (see the outer shapes of the main cores 211 and 311 shown in FIG. 4). That is, the main core 211 and the edge cores 212 and 213 are so-called E-shaped cores. However, as is clear from the outer shapes of the main cores 211 and 311 in FIG. 4, this embodiment illustrates a case in which the length in the z-axis direction of the central legs 2112 and 3112, the length in the z-axis direction of the upstream legs 2113 and 3113, and the length in the z-axis direction of the downstream legs 2114 and 3114 are the same. In this case, the distances between the tip surfaces of the central legs 2112 and 3112, the tip surfaces of the upstream legs 2113 and 3113, and the tip surfaces of the downstream legs 2114 and 3114 and the transport planned surface CP are the same.

[0041] The distances between the intended transport surface CP and the tip surfaces of the central legs 2112, 3112, the upstream legs 2113, 3113, and the downstream legs 2114, 3114 may be different. For example, the distance between the intended transport surface CP and the tip surfaces of the central legs 2112, 3112 may be longer than the distances between the intended transport surface CP and the tip surfaces of the upstream legs 2113, 3113 and the downstream legs 2114, 3114.

[0042] As shown in FIG. 1 and FIG. 2, the length of the winding portion of the coils 230, 330 in the x-axis direction is longer than the width of the strip steel sheet 100. Specifically, the length of the winding portion of the coils 230, 330 in the x-axis direction is longer than the maximum processable width of the induction heating device. As a result, when viewed from the z-axis direction, the coils 230, 330 have a length in the x-axis direction that covers the maximum processable width of the induction heating device. Here, the maximum processable width of the induction heating device is the range in the x-axis direction in which the strip steel sheet 100 with the maximum width that the induction heating device can heat may exist even if the strip steel sheet 100 moves in the positive or negative direction of the x-axis (due to meandering, etc.). In addition, both ends of the winding portion of the coils 230, 330 in the x-axis direction are located outside both ends of the strip steel sheet 100 in the x-axis direction (i.e., both ends of the maximum processable width of the induction heating device). That is, the end of the winding portion of the coils 230, 330 on the positive side of the x-axis is located further on the positive side of the x-axis than the end of the steel strip 100 (i.e., the maximum processable width of the induction heating device). Also, the end of the winding portion of the coils 230, 330 on the negative side of the x-axis is located further on the negative side of the x-axis than the end of the steel strip 100 (i.e., the maximum processable width of the induction heating device).

[0043] 1, an AC power source 400 is electrically connected to the coils 230 and 330. As shown in FIG 1, in this embodiment, one end 231 of the winding portion of the coil 230 is electrically connected to one terminal 401 of the two output terminals of the AC power source 400. In addition, the other end 232 of the winding portion of the coil 230 is electrically connected to the other terminal 402 of the two output terminals of the AC power source 400.

[0044] Among the two ends of the winding portion of the coil 330, one end 331 located opposite one end 231 of the winding portion of the coil 230 in the z-axis direction is electrically connected to one terminal 401 of the two output terminals of the AC power supply 400. Among the two ends of the winding portion of the coil 330, the other end 332 located opposite the other end 232 of the winding portion of the coil 230 in the z-axis direction is electrically connected to the other terminal 402 of the two output terminals of the AC power supply 400.

[0045] In this manner, in this embodiment, the coils 230 and 330 are connected in parallel to the AC power supply 400 such that, when viewed from the AC power supply 400, the coils 230 and 330 have the same winding direction.

[0046] Therefore, as shown in FIG. 1, when viewed from the same viewpoint at the same time, the directions of the alternating currents flowing in the opposing regions of coil 230 and coil 330 are the same (see the arrows shown within coil 230 and coil 330 in FIG. 1).

[0047] The arrows shown in coils 230 and 330 in FIG. 1 indicate that, when the induction heating device is viewed from above, the direction of the AC current flowing through coil 230 is clockwise (right-handed), and the direction of the AC current flowing through coil 330 is clockwise (right-handed). Surroundings ) is indicated.

[0048] Here, the instantaneous values ​​of the AC currents flowing from AC power supply 400 to coils 230 and 330 are the same. The waveform of the AC current is, for example, a sine wave. However, the waveform of the AC current is not limited to a sine wave. The waveform of the AC current may be the same as a waveform that can be used in a general induction heating device.

[0049] As described above, the coils 230, 330 are arranged on the front side and the back side of the intended transport surface CP so that the alternating magnetic fields generated by the passage of alternating currents in the same direction intersect with the intended transport surface CP of the steel strip 100. In this embodiment, a case where a pair of coils is formed by two coils 230, 330 is illustrated. One of the coils constituting the pair of coils is coil 230, and the other coil constituting the pair of coils is coil 330.

[0050] Note that, if the above-mentioned AC current flows through coil 230 and coil 330, it is not necessary to connect a single AC power supply to coils 230 and 330 as shown in Fig. 1. For example, the AC power supply connected to coil 230 and the AC power supply connected to coil 330 may be different AC power supplies as long as the frequencies of the currents flowing from these AC power supplies are synchronized.

[0051] In addition, in the present embodiment, the number of coils arranged on the front side of the transport surface CP among the pair of coils provided in the induction heating device and the number of coils arranged on the rear side of the transport surface CP among the pair of coils are 1, respectively. However, the number of coils arranged on the front side of the transport surface CP among the pair of coils provided in the induction heating device and the number of coils arranged on the rear side of the transport surface CP among the pair of coils may be 2 or more. For example, two or more coils may be arranged on the front side of the transport surface CP with a gap between them in the y-axis direction. Similarly, for example, two or more coils may be arranged on the rear side of the transport surface CP with a gap between them in the y-axis direction. For example, an alternating current flows in two or more coils arranged on the front side of the transport surface CP among the pair of coils provided in the induction heating device, in the same direction as the current flowing in the coil 230. In this case, for example, an alternating current flows in two or more coils arranged on the rear side of the transport surface CP among the pair of coils.

[0052] In FIG. 2, cooling fins 260a, 260b, 260c, and 260d are arranged between the partial edge cores 212a and 212b, between the partial edge cores 212b and 212c, between the partial edge cores 212c and 212d, and between the partial edge core 212d and the main core 211, respectively. Similarly, cooling fins 260e, 260f, 260g, and 260h are arranged between the partial edge cores 213a and 213b, between the partial edge cores 213b and 213c, between the partial edge cores 213c and 213d, and between the partial edge core 213d and the main core 211, respectively. In this embodiment, a case where the intervals between them are fixed (not changed) is illustrated. However, the intervals between them may be changeable. In addition, the lengths in the x-axis direction of each of the partial edge cores 212a to 212d and 213a to 213d may be the same or different from each other.

[0053] The cooling fins 260a to 260h are an example of a cooling member for cooling the main core 211 and the partial edge cores 212a to 212d and 213a to 213d. In this embodiment, the cooling fins 260a to 260h are fin-shaped non-magnetic conductive plates. The cooling fins 260a to 260h are made of, for example, a copper plate.

[0054] The cooling pipes 270a to 270h are attached on the cooling fins 260a to 260h. The cooling pipes 270a to 270h are an example of a cooling member for cooling the main core 211, the partial edge cores 212a to 212d, 213a to 213d, and the bridge cores 220a, 220b. In this embodiment, the cooling pipes 270a to 270h are non-magnetic conductive pipes.

[0055] The cooling fins 260a-260h and the cooling tubes 270a-270h attached thereon are in contact with each other. Also, Fig. 3 and Fig. 4 show an example in which the overall outer shape of the yz cross section of the region including the cooling fins 260a-260h and the cooling tubes 270a-270h is the same as the outer shape of the yz cross section of the original core 210 (the main core 211 and the partial edge cores 212a-212d, 213a-213d). That is, Fig. 3 and Fig. 4 show an example in which the shape and size of the entire region of the cooling fins 260a and the cooling tubes 270a in Fig. 3 are the same as the shape and size of the region of the main core 211 in Fig. 4.

[0056] A cooling medium such as cooling water is supplied to the inside of the cooling pipes 270a-270h. Heat is conducted from the partial edge cores 212a-212d, 213a-213d, etc. to the cooling medium via the cooling pipes 270a-270h and the cooling fins 260a-260h. This promotes cooling of the partial edge cores 212a-212d, 213a-213d, etc.

[0057] The shield plates 240a and 240b are an example of a shielding member for preventing overheating of the edge portion of the strip steel plate 100 by adjusting (reducing) the degree of electromagnetic coupling between the coil 230 and the strip steel plate 100. Specifically, the shield plates 240a and 240b are non-magnetic conductive plates arranged between the edge portion of the strip steel plate 100 and the partial edge cores 212a to 212d, 213a to 213d with a gap therebetween. The length of the shield plates 240a to 240b in the y-axis direction is preferably longer than the length of the original core 210 in the y-axis direction. In addition, it is preferable that the upstream end of the shield plates 240a and 240b is located upstream of the upstream end of the original core 210. Similarly, it is preferable that the downstream end of the shield plates 240a and 240b is located downstream of the downstream end of the original core 210 (see FIG. 3).

[0058] The shield plates 240a to 240b may move in the x-axis direction within their movable range. The shield plates 240a, 240b may move according to the width of the steel strip 100 so that the shield plates 240a, 240b are positioned between the edge portion of the steel strip 100 and the partial edge cores 212a to 212d, 213a to 213d. The shield plates 240a, 240b may also move in the x-axis direction when the steel strip 100 meanders. For example, the shield plates 240a, 240b may move in the x-axis direction (the direction in which the steel strip 100 meanders) by an amount equal to the amount of meandering of the steel strip 100.

[0059] The configuration for moving the shield plates 240a-240b in the x-axis direction is realized by a known technique using, for example, an actuator for moving the shield plates 240a-240b in the x-axis direction. Therefore, a detailed description of this configuration will be omitted here. The configuration for detecting the amount of meandering of the plates is also realized by a known technique using a sensor that detects the position of the end of the plate in the x-axis direction. Therefore, a detailed description of this configuration will be omitted here. These known techniques include, for example, the technique described in Japanese Patent No. 6658977.

[0060] Furthermore, when the meandering amount of the steel strip 100 is on the order of centimeters (e.g., less than 10 cm), it is preferable to move only the shield plates 240a, 240b in the x-axis direction. When the meandering amount of the steel strip 100 exceeds the order of centimeters (e.g., 10 cm or more), it is preferable to move the entire induction heating device (upper inductor 200 and lower inductor 300) in the x-axis direction. For example, the entire induction heating device (upper inductor 200 and lower inductor 300) may be moved in the x-axis direction (the direction in which the steel strip 100 meanders) by the same amount as the meandering amount of the steel strip 100.

[0061] Due to a magnetic field based on eddy currents flowing through the shield plates 240a, 240b, the temperatures of the main core 211 and the edge cores 212, 213 are highest near the upper end of the x-axis direction of the shield plates 240a, 240b that is closer to the center of the plate of the induction heating device. Therefore, in this embodiment, a case will be illustrated in which the position in the x-axis direction (x coordinate) of the main core 211 and the positions in the x-axis direction of the edge cores 212, 213 are determined as follows.

[0062] The gap region in the x-axis direction formed in the main core 211 and the edge cores 212, 213 is referred to as a core gap region. In this embodiment, the case where the core gap region is a region where the cooling fins 260a-260h and the cooling tubes 270a-270h are arranged is illustrated. In this embodiment, the case where the position of the main core 211 in the x-axis direction and the positions of the partial edge cores 212a-212d, 213a-213d in the x-axis direction are determined so that the end of the core gap region closest to the plate center among the core gap regions present at the position facing the bridge cores 220a, 220b is arranged inside (toward the plate center) of the shield plates 240a, 240b when the shield plates 240a, 240b move to a position closest to the center position in the x-axis direction of the induction heating device within the movable range of the shield plates 240a, 240b in the x-axis direction is determined. Figure 2 illustrates an example in which the end portion of the core gap region closest to the plate center among the core gap regions located opposite bridge cores 220a, 220b is the end portion of cooling fins 260d, 260h on the plate center side.

[0063] By determining the position of the main core 211 in the x-axis direction and the positions of the partial edge cores 212a-212d, 213a-213d in the x-axis direction in this manner, the regions between the main core 211 and the partial edge cores 212a-212d, 213a-213d can be positioned close to the regions where the temperatures of the main core 211 and the edge cores 212, 213 become high. Therefore, the temperatures of the regions where the temperatures of the main core 211 and the edge cores 212, 213 become high can be reduced. Furthermore, if the cooling fins 260a-260h and the cooling tubes 270a-270h are arranged in the regions between the main core 211 and the partial edge cores 212a-212d, 213a-213d as in this embodiment, the temperatures of the regions where the temperatures of the main core 211 and the edge cores 212, 213 become high can be further reduced.

[0064] Here, the plate center side refers to the side closer to the center position in the x-axis direction of the induction heating device. On the positive side of the x-axis from the center in the x-axis direction of the induction heating device, the plate center side is the negative side of the x-axis. On the other hand, on the negative side of the x-axis from the center in the x-axis direction of the induction heating device, the plate center side is the positive side of the x-axis. For example, in FIG. 2, the position of the main core 211 in the x-axis direction and the positions of the partial edge cores 212a to 212d and 213a to 213d in the x-axis direction are determined so that when the shield plate 240a moves to the most negative side of the x-axis within the movable range of the shield plate 240a, the end of the cooling fin 260d on the negative side of the x-axis is located on the negative side of the x-axis from the end of the shield plate 240a on the negative side of the x-axis.

[0065] The bridge cores 220a and 220b are made of ferromagnetic material that can be magnetically coupled to at least one of the main core 211 and the partial edge cores 212a to 212d and 213a to 213d. Note that at least one of the main core 211 and the partial edge cores 212a to 212d and 213a to 213d refers to only the main core, only one or more partial edge cores, or the main core and one or more partial edge cores.

[0066] Here, the two cores can be magnetically coupled to each other when the two cores are excited by an AC current flowing through a coil provided in the induction heating device. When no AC current flows through a coil provided in the induction heating device, the two cores are not magnetically coupled to each other. The two cores are magnetically coupled to each other when a spin-spin coupling occurs between the constituent atoms of one of the two cores and the constituent atoms of the other core. In order to easily check whether the two cores are magnetically coupled to each other, the two cores may be considered to be magnetically coupled to each other in the following cases. That is, the two cores may be considered to be magnetically coupled to each other when the ratio of the magnetic flux density of the core with the lower magnetic flux density generated in the core to the magnetic flux density of the core with the higher magnetic flux density generated in the core is 0.2 or more. The ratio is a design target of the induction heating device determined by a designer when the device is designed. The ratio may be 0.2 as described above, but may also be 0.3 or more, 0.4 or more, 0.5 or more, or 0.6 or more, as necessary.

[0067] The bridge cores 220a and 220b need to be arranged on the rear side of the partial cores (in this embodiment, the main core 211 and the partial edge cores 212a to 212d, 213a to 213d). The reason for this will be explained below.

[0068] Even if the bridge cores 220a and 220b are arranged on the side of the partial cores (the main core 211 and the partial edge cores 212a to 212d, 213a to 213d in this embodiment) where the intended transport surface CP exists, the bridge cores 220a and 220b can be magnetically coupled to the partial cores. However, when the bridge cores 220a and 220b and the partial cores are arranged in this manner, at least a part of the magnetic flux that should penetrate the strip steel sheet 100 penetrates the bridge cores 220a and 220b. As a result, the strip steel sheet 100 cannot be heated sufficiently. In addition, when the bridge cores 220a and 220b are arranged on the side surfaces (upstream or downstream side surfaces, or x-axis direction side surfaces) of the partial cores (the main core 211 and the partial edge cores 212a to 212d, 213a to 213d in this embodiment), the degree of magnetic coupling between the bridge cores 220a and 220b and the partial cores becomes relatively small. As a result, the effect of restoring the magnetic flux density in the partial edge cores 212a-212d, 213a-213d, which has been reduced by scattering the partial edge cores 212a-212d, 213a-213d in the x-axis direction, to the same level as the magnetic flux density in the main core 211 by the bridge cores 220a, 220b is also reduced. Furthermore, when the bridge cores 220a, 220b are disposed on the side surfaces of the partial cores, at least a part of the magnetic flux that should penetrate the strip steel plate 100 penetrates the bridge cores 220a, 220b. As a result, the strip steel plate 100 may not be heated sufficiently, or a temperature gradient may be easily generated in the strip steel plate 100 in the width direction (x-axis direction). For the above reasons, the bridge cores 220a and 220b need to be disposed on the rear surface side of the partial cores.

[0069] In this embodiment, the bridge cores 220a and 220b are made of soft magnetic ferrite, which is an example of a ferromagnetic material with no anisotropy in the magnetization direction. In addition, in this embodiment, the bridge core 220a is magnetically coupled to the main core 211 and the partial edge cores 212a to 212d, and the bridge core 220b is magnetically coupled to the main core 211 and the partial edge cores 213a to 213d. In this case, the partial edge cores 212a to 212d and the partial edge cores 213a to 213d are also magnetically coupled via the bridge cores 220a and 220b and the main core 211. That is, all the cores constituting the original core 210 (the main core 211 and the partial edge cores 212a to 212d, 213a to 213d) are magnetically coupled via the bridge cores 220a and 220b.

[0070] By magnetically coupling the main core 211 and the edge cores 212 and 213 via the bridge cores 220a and 220b, the inductance of the induction heating device when the bridge cores 220a and 220b are present is greater than the inductance of the induction heating device when the bridge cores 220a and 220b are not present. In this way, the bridge cores 220a and 220b, the main core 211, and the edge cores 212 and 213 can be magnetically coupled.

[0071] If the bridge cores 220a and 220b were not present, the main core 211 and the partial edge cores 212a to 212d and 213a to 213d would be separated by the regions (the cooling fins 260a to 260h in this embodiment) between the main core 211 and the partial edge cores 212a to 212d and 213a to 213d. Therefore, the magnetic flux density in each of the partial edge cores 212a to 212d and 213a to 213d would be small. In contrast, in this embodiment, by using the bridge cores 220a and 220b, such a small magnetic flux density can be increased. For example, by using the bridge cores 220a and 220b, the magnetic flux density in each of the partial edge cores 212a to 212d and 213a to 213d can be restored to the same level as the magnetic flux density in the main core 211. For example, the magnetic flux density in each of the partial edge cores 212a to 212d and 213a to 213d is preferably 0.75 times or more, and more preferably 0.9 times or more, of the magnetic flux density in the main core 211. However, as described above, it is only necessary that the main core 211 and the partial edge cores 212a to 212d and 213a to 213d are magnetically coupled to each other.

[0072] As shown in Fig. 2, the bridge cores 220a and 220b are arranged on both sides in the x-axis direction with a gap between them. Fig. 2 also illustrates a case in which the bridge cores 220a and 220b are arranged to overlap a portion of the main core 211 when viewed from the z-axis direction. Fig. 2 also illustrates a case in which the bridge cores 220a and 220b are arranged to overlap at least a portion of each of the partial edge cores 212a to 212d and 213a to 213d when viewed from the z-axis direction.

[0073] Here, an example of the arrangement of the bridge cores 220a and 220b in this embodiment will be described in more detail with reference to Fig. 2. The end face (lower face) of the bridge core 220a on the intended transfer surface CP side is in contact with a part of the rear side (upper face) of the main core 211, the entire rear end faces (upper faces) of the partial edge cores 212a to 212d arranged on the positive side (one side) of the x-axis from the main core 211, and the rear end faces (upper ends) of the cooling tubes 270a to 270d. The end face (lower face) of the bridge core 220b on the intended transfer surface CP side is in contact with a part of the rear end face (upper face) of the main core 211, the entire rear end faces (upper faces) of the partial edge cores 213a to 213d arranged on the negative side (other side) of the x-axis from the main core 211, and the rear end faces (upper ends) of the cooling tubes 270e to 270h.

[0074] However, as long as the bridge cores 220a and 220b can be magnetically coupled to the main core 211 and the edge cores 212 and 213, the bridge cores 220a and 220b may not be in contact with the main core 211, the edge cores 212 and 213, and the cooling tubes 270a to 270h. For example, the bridge cores 220a and 220b may be arranged with a gap between them and the main core 211 and the edge cores 212 and 213. The bridge cores 220a and 220b may be in contact with or face only one of the main core 211 and the edge cores 212 and 213 with a gap between them. The bridge cores 220a and 220b may be in contact with or face a partial region of at least one of the partial edge cores 212a to 212d and 213a to 213d with a gap between them.

[0075] The bridge cores 220a, 220b are preferably arranged as follows. 2, the overlap length L of the bridge cores 220a, 220b on the plate center side is the length in the x-axis direction of the portion where the main core 211 and the edge cores 212, 213 overlap with the bridge cores 220a, 220b in a region closer to the plate center than the core gap region closest to the plate center among the core gap regions present in positions facing the bridge cores 220a, 220b when viewed in the z-axis direction. Fig. 2 illustrates an example in which the region closer to the plate center than the core gap region closest to the plate center among the core gap regions present in positions facing the bridge cores 220a, 220b is the region of the main core 211.

[0076] The plate center side wrap length L of the bridge cores 220a and 220b is preferably equal to or greater than the length α, and more preferably equal to or greater than the length β. This is because the partial edge cores 212a to 212d and 213a to 213d and the main core 211 can be reliably magnetically coupled via the bridge cores 220a and 220b. For example, in FIG. 2, it is preferable that the end of the bridge core 220a on the negative side of the x-axis is disposed at a position on the negative side of the x-axis relative to the end of the cooling fin 260d on the negative side of the x-axis so that the plate center side wrap length L of the bridge core 220a is equal to or greater than the length α. It is more preferable that the end of the bridge core 220a on the negative side of the x-axis is disposed at a position on the negative side of the x-axis relative to the end of the cooling fin 260d on the negative side of the x-axis so that the plate center side wrap length L of the bridge core 220a is equal to or greater than the length β.

[0077] The lengths α and β are obtained, for example, from the results of known electromagnetic field analysis (numerical analysis) using mathematical expressions, the finite element method, or the like. However, the lengths α and β may be simply determined as follows. That is, the minimum value of the length in the x-axis direction of the main core 211 and the partial edge cores 212a-212d and 213a-213d, excluding the main core 211 arranged closest to the plate center (i.e., the partial edge cores 212a-212d), may be set to the length α and the maximum value to the length β. In FIG. 2, for example, the cores that overlap with the bridge core 220a when viewed from the z-axis direction are the main core 211 and the partial edge cores 212a-212d. The minimum value of the lengths L1 to L4 in the x-axis direction of the partial edge cores 212a to 212d, excluding the main core 211 arranged closest to the plate center among the main core 211 and the partial edge cores 212a to 212d, is the length L3 (=L2=L1) in the x-axis direction of the partial edge cores 212b to 212d, and the maximum value is the length L4 in the x-axis direction of the partial edge core 212a. Therefore, the plate center side wrap length L of the bridge core 220a is preferably set to be equal to or greater than the minimum value of the lengths in the x-axis direction of the partial edge cores 212a to 212d (i.e., the length L3 (=L2=L1) of the partial edge cores 212b to 212d in the x-axis direction), and more preferably set to be equal to or greater than the maximum value of the lengths L1 to L4 in the x-axis direction of the partial edge cores 212a to 212d (i.e., the length L4 in the x-axis direction of the partial edge core 212a). Similarly, the plate center side wrap length L of the bridge core 220b is preferably equal to or greater than the minimum value of the lengths in the x-axis direction of the partial edge cores 213a to 213d (i.e., the length L3 (= L2 = L1) in the x-axis direction of the partial edge cores 213b to 213d), and more preferably equal to or greater than the maximum value of the lengths L1 to L4 in the x-axis direction of the partial edge cores 213a to 213d (i.e., the length L4 in the x-axis direction of the partial edge core 213a).

[0078] The length α is the lower limit of a preferred range of the plate center side wrap length L of the bridge cores 220a, 220b. As already explained, as a simple method of determining the length α, the minimum value of the lengths in the x-axis direction of the cores excluding the main core 211 (i.e., the partial edge cores 212a-212d, 213a-213d) may be set as α. However, since the length in the x-axis direction of the main core 211 is greater than the lengths in the x-axis direction of the partial edge cores 212a-212d, 213a-213d, there is no need to exclude the main core 211 when determining the length α in a simple manner. For this reason, in the case of FIG. 8 In the case of such an embodiment, when the length α is simply determined, the partial cores that are discrete in the x-axis direction (i.e., 8 The minimum value of the length of each of the partial original cores (710a to 710f) in the x-axis direction may be set as α.

[0079] On the other hand, there is no need to particularly define an upper limit for the wrap length L of the bridge cores 220a, 220b on the plate center side.

[0080] 2, the end-side overlap length L' of the bridge cores 220a, 220b is the length in the x-axis direction of the portion where the bridge cores 220a, 220b overlap with the partial edge cores 212a, 213a, which are located closest to the end among the main core 211 and the partial edge cores 212a-212d, 213a-213d, when viewed from the z-axis direction. The end-side overlap length L' of the bridge cores 220a, 220b is preferably equal to or greater than the length α. The end-side overlap length L' of the bridge cores 220a, 220b may be equal to or greater than the length β, for example.

[0081] Also, it is not necessary to prohibit the end of the bridge core 220a or 220b on the plate end side from the end of the partial edge cores 212a and 213a on the plate end side (outside). However, basically, it is not necessary for the end of the bridge core 220a or 220b on the plate end side to protrude from the end of the partial edge cores 212a and 213a on the plate end side (outside). This is because the effect of improving the magnetic flux density of the core by the part protruding on the plate end side (the effect of restoring the magnetic flux density in the partial edge cores 212a to 212d and 213a to 213d, which has become smaller due to the partial edge cores 212a to 212d and 213a to 213d being dispersed in the x-axis direction, to the same level as the magnetic flux density in the main core 211 by the bridge cores 220a and 220b) is relatively small. Here, the plate end side is the opposite side to the plate center side. The end of the bridge core 220a on the plate end side and the end of the edge core 212a on the plate end side are the ends on the positive side of the x-axis. a The end portion on the plate end side of the induction heating device is the end portion on the negative side of the x-axis. On the positive side of the x-axis from the center of the induction heating device in the x-axis direction, the plate end side is on the positive side of the x-axis. On the other hand, on the negative side of the x-axis from the center of the induction heating device in the x-axis direction, the plate end side is on the negative side of the x-axis.

[0082] Moreover, the height (length in the z-axis direction) H of the bridge cores 220a and 220b is preferably 0.5 times or more the smaller of the lengths h and α (0.5×h and 0.5×α or more). This is because it is possible to reliably realize that the partial edge cores 212a to 212d and 213a to 213d and the main core 211 are magnetically coupled via the bridge cores 220a and 220b. Moreover, the thickness (length in the z-axis direction) H of the bridge cores 220a and 220b is more preferably 1.0 times or more the smaller of the lengths h and α (h and α or more). This is because the partial edge cores 212a to 212d and 213a to 213d and the main core 211 are magnetically coupled more firmly via the bridge cores 220a and 220b. There is no need to specifically set an upper limit for the thickness H (length in the z-axis direction) of the bridge cores 220a, 220b, but it may be 2.0 times the larger of the lengths h and α (the larger of 2.0 × h and 2.0 × α) or 1.0 times the smaller of the lengths h and α (the smaller of h and α).

[0083] Here, the length h is the length in the z-axis direction of the area of ​​the main core 211 and the edge cores 212, 213 that is on the rear side of the coil 230, relative to the coil 230 arranged in the main core 211 and the edge cores 212, 213, as shown in Figures 2 to 4.

[0084] Furthermore, the ratio (=BL / CL) of the length BL of the bridge cores 220a, 220b in the y-axis direction to the length CL of the main core 211 and the partial edge cores 212a-212d, 213a-213d in the y-axis direction is preferably 0.2 or more, because this ensures that the partial edge cores 212a-212d, 213a-213d and the main core 211 are magnetically coupled via the bridge cores 220a, 220b. From the viewpoint of firmly magnetically coupling the partial edge cores 212a-212d, 213a-213d to the main core 211 via the bridge cores 220a, 220b, it is more preferable that the ratio (=BL / CL) of the length BL of the bridge cores 220a, 220b in the y-axis direction to the length CL of the main core 211 and the partial edge cores 212a-212d, 213a-213d in the y-axis direction is more than 0.5 or is 0.6 or more. There is no need to set an upper limit to the ratio (=BL / CL), but it may be 1.0 or 0.8.

[0085] Furthermore, the positions of the upstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d in the y-axis direction may coincide with the positions of the upstream ends (negative side of the y-axis) of the bridge cores 220a, 220b in the y-axis direction. Furthermore, it is preferable that the upstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d are located upstream of the upstream ends of the bridge cores 220a, 220b or are located at the same positions. The upstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d may be located upstream of the upstream ends of the bridge cores 220a, 220b. However, the effect of improving the magnetic flux density of the core (the effect of restoring the magnetic flux density in the partial edge cores 212a to 212d, 213a to 213d, which has become smaller as a result of the partial edge cores 212a to 212d, 213a to 213d being dispersed in the x-axis direction, to the same level as the magnetic flux density in the main core 211 by the bridge cores 220a, 220b) is relatively small. For this reason, it is not necessary for the upstream ends of the bridge cores 220a, 220b to protrude upstream from the upstream ends of the main core 211 and the partial edge cores 212a to 212d, 213a to 213d. Similarly, the positions in the y-axis direction of the downstream ends (positive side of the y-axis) of the main core 211 and the partial edge cores 212a to 212d, 213a to 213d may coincide with the positions in the y-axis direction of the downstream ends of the bridge cores 220a, 220b. Further, the downstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d may be located downstream of the downstream ends of the bridge cores 220a, 220b. The downstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d may be located upstream of the downstream ends of the bridge cores 220a, 220b. However, the effect of improving the magnetic flux density of the core (the effect of restoring the magnetic flux density in the partial edge cores 212a-212d, 213a-213d, which has been reduced by the partial edge cores 212a-212d, 213a-213d being dispersed in the x-axis direction, to the same level as the magnetic flux density in the main core 211 by the bridge cores 220a, 220b) is relatively small.Therefore, the downstream ends of the bridge cores 220a and 220b do not need to protrude downstream beyond the downstream ends of the main core 211 and the partial edge cores 212a to 212d and 213a to 213d.

[0086] Furthermore, if the upstream ends of the bridge cores 220a, 220b are not located upstream of the upstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d, and the downstream ends of the bridge cores 220a, 220b are not located downstream of the downstream ends of the main core 211 and the partial edge cores 212a-212d, 213a-213d, the center position in the y-axis direction of the bridge cores 220a, 220b may coincide with the center position in the y-axis direction of the main core 211 and the partial edge cores 212a-212d, 213a-213d.

[0087] When the induction heating device is viewed from the z-axis direction, it is not necessary to prohibit the bridge cores 220a and 220b from protruding outward from the region connecting both ends (ends on the plate end side) of the main core 211 and the partial edge cores 212a to 212d, 213a to 213d in the x-axis direction and both ends on the upstream side and downstream side in the y-axis direction. However, basically, the bridge cores 220a and 220b do not need to protrude outward from the region connecting these ends. This is because the effect of improving the magnetic flux density of the core by the protruding parts of the bridge cores 220a and 220b (the effect of restoring the magnetic flux density in the partial edge cores 212a to 212d, 213a to 213d, which has become smaller due to the partial edge cores 212a to 212d, 213a to 213d being dispersed in the x-axis direction, to the same level as the magnetic flux density in the main core 211 by the bridge cores 220a and 220b) is relatively small.

[0088] The length values ​​of each part of the induction heating device, including the length h, L1 to L4, BL, and CL, are determined, for example, as follows. That is, a simulation test or electromagnetic field analysis is performed to simulate induction heating of the steel strip 100 with the induction heating device under a plurality of conditions in which the length values ​​of each part of the induction heating device are different. Then, the length values ​​of each part of the induction heating device are determined from the results of the simulation test or electromagnetic field analysis in which a desired temperature distribution is obtained as the temperature distribution in the x-axis direction of the steel strip 100. When the induction heating device has a part whose length is restricted by the installation space or the like, the length value of the part is determined to satisfy the restriction. For example, the size, shape, and position of the bridge cores 220a and 220b are determined so as not to affect the movement of other members such as the coil 230 and the shield plates 240a and 240b.

[0089] As described above, this embodiment illustrates a case where the bridge cores 220a, 220b are separate cores from the main core 211 and the edge cores 212, 213. Therefore, as shown in Figures 1 and 2, the bridge cores 220a, 220b have borders at the boundaries between the main core 211 and the edge cores 212, 213. In the above description, it is preferable that the positions of the parts of the upper inductor 200 other than the shield plates 240a and 240b are fixed.

[0090] Like the upper inductor 200, the lower inductor 300 also includes an original core 310 having a main core 311 and edge cores 312, 313 (partial edge cores 312a-312d, 313a-313d), bridge cores 320a, 320b, a coil 330, shield plates 340a, 340b, cooling fins 360a-360h, and cooling tubes 370a-370h, and has the same configuration as the upper inductor 200.

[0091] In this embodiment, a core set is configured by the original core 210 and the bridge cores 220a, 220b, and the original core 310 and the bridge cores 320a, 320b, one for each pair of coils. In addition, in this embodiment, a core set is configured by the original core 210 and the bridge cores 220a, 220b, and the original core 310 and the bridge cores 320a, 320b.

[0092] As described above, in this embodiment, the bridge cores 220a, 220b, 320a, and 320b can increase the range and amount of the main magnetic flux passing through the main cores 211 and 311 and the edge cores 212, 213, 312, and 313, compared to a case in which the bridge cores 220a, 220b, 320a, and 320b are not present. Therefore, the main cores 211 and 311 and the edge cores 212, 213, 312, and 313 can be efficiently Magnetic It can be bonded electrically.

[0093] Fig. 5 is a diagram showing an example of the relationship between the position in the x-axis direction (position in the sheet width direction) and the temperature (steel sheet surface temperature) of the strip steel sheet 100. The vertical axis of Fig. 5 (steel sheet surface temperature) is a relative value. In Fig. 5, graph 501 is a graph in the case where the induction heating device of this embodiment is used. On the other hand, graph 502 is a graph in the case where the induction heating device of the comparative example is used. The induction heating device of this embodiment is provided with bridge cores 220a, 220b, 320a, and 320b, whereas the induction heating device of the comparative example is not provided with bridge cores 220a, 220b, 320a, and 320b. The other configurations, operating conditions, and operating environments are the same between the induction heating device of this embodiment and the induction heating device of the comparative example.

[0094] 5, the temperature deviation in graph 501 is 21.5% smaller than the temperature deviation in graph 502. Therefore, it can be seen that providing the bridge cores 220a, 220b, 320a, 320b makes it possible to suppress a decrease in temperature of the entire steel strip 100 and to suppress bias in the temperature distribution in the x-axis direction, compared to a case in which the bridge cores 220a, 220b, 320a, 320b are not provided.

[0095] As described above, in this embodiment, the bridge cores 220a and 220b can magnetically couple the main core 211 and the edge cores 212 and 213. Therefore, the magnetic coupling (spin-spin coupling) between the main core 211 and the edge cores 212 and 213 (partial edge cores 212a to 212d, 213a to 213d) and the bridge cores 220a and 220b can be increased. This makes it possible to increase the magnetic flux density in the main core 211 and the magnetic flux density in the edge cores 212 and 213 compared to the case where the bridge cores 220a and 220b are not provided. The above is the same for the lower inductor 300.

[0096] In Patent Document 6, the screen 14 is made of a conductor. The magnetic pad 16 is disposed on an armature 15 that supports the screen 14. Therefore, even if the magnetic pad 16 is a ferromagnetic material, the screen 14 (conductor) exists between the magnetic bars 8 and the magnetic pad 16. Therefore, the magnetic bars 8 and the magnetic pad 16 are not magnetically coupled. That is, the magnetic pad 16 does not function as a bridge core as described in this embodiment. Moreover, since the magnetic pad 16 is not located on the back side of the core, it does not function as a bridge core as described in this embodiment.

[0097] Moreover, the armature 12 is for positioning the magnetic bar 8, and is not a core that is magnetically coupled to the magnetic bar 8. Even if the armature 12 is a ferromagnetic material, the thickness of the armature 12 is thin, so that the magnetic resistance of the armature 12 is extremely high. That is, even if the main magnetic flux passing through the magnetic bar 8 tries to pass through the armature 12, the armature 12 becomes magnetically saturated and is equivalent to a non-magnetic material. In this way, even if the armature 12 is a ferromagnetic material, it becomes equivalent to a non-magnetic material and is not magnetically coupled to the magnetic bar 8. That is, the armature 12 does not function as a bridge core as described in this embodiment. Moreover, since the armature 12 is not located on the back side of the core, it does not function as a bridge core as described in this embodiment.

[0098] In addition, in the technology of Patent Document 6, the multiple magnetic bars 8 are arranged with a gap therebetween. Therefore, the alternating magnetic field, which is increased by the multiple magnetic bars 8, leaks from the area between the multiple magnetic bars 8 and diffuses to the surroundings. There is a risk that the alternating magnetic field diffused from the multiple magnetic bars 8 heats surrounding objects (e.g., electronic devices). There is also a risk that the alternating magnetic field diffused from the multiple magnetic bars 8 generates noise in surrounding objects. There is also a risk that the alternating magnetic field diffused from the multiple magnetic bars 8 causes unintended heating of the strip steel plate 100. In this case, there is a risk that the temperature distribution in the x-axis direction of the strip steel plate 100 becomes non-uniform. Since the location where the induction heating device is installed is not under the same conditions, it is practically impossible to predict whether the strip steel plate 100 will cause unintended heating. If the total power of the induction heating device increases due to unintended heating of the strip steel plate 100, there is a risk that the heating efficiency of the entire induction heating device will decrease. In this case, there is a risk that the method of supplying power to the induction heating device will have to be reconsidered in order to heat the steel strip 100 to a desired temperature.

[0099] In contrast, in this embodiment, the bridge cores 220a and 220b magnetically couple the main core 211 and the edge cores 212 and 213. This makes it possible to prevent the alternating magnetic field, which is intensified by the cores (the main core 211 and the edge cores 212 and 213), from diffusing to the surroundings. This makes it possible to prevent the various adverse effects described above.

[0100] Furthermore, in this embodiment, the bridge cores 220a and 220b are made of soft magnetic ferrite (a ferromagnetic material with no anisotropy in the magnetization direction). This further promotes the coupling of the spins of the constituent atoms between the main core 211 and the edge cores 212 and 213 and the bridge cores 220a and 220b. This increases the magnetic flux density in the main core 211 and the edge cores 212 and 213.

[0101] Furthermore, in this embodiment, the cooling fins 260a to 260h and the cooling tubes 270a to 270h can suppress an increase in temperature of the original core 210 and an increase in temperature of the bridge cores 220a and 220b.

[0102] In this embodiment, the bridge cores 220a, 220b are separate from the main core 211 and the edge cores 212, 213. This facilitates assembly and maintenance of the induction heating device. As long as the overall shape and size are the same, the same bridge cores 220a, 220b can be applied to induction heating devices of different specifications (for example, induction heating devices with different numbers of partial edge cores). The above also applies to the lower inductor 300.

[0103] As described above, in this embodiment, it is possible to provide an induction heating device that can simultaneously suppress both the rise in core temperature and the decrease in the magnitude of the alternating magnetic field applied to the strip steel sheet 100. In particular, as the capacity of the induction heating device increases, the effect of simultaneously suppressing the rise in core temperature and the decrease in the magnitude of the alternating magnetic field applied to the strip steel sheet 100 increases. The capacity of the induction heating device in this embodiment is not limited, but from this viewpoint, it is preferable that the capacity of the induction heating device is on the order of tens of kW or more (e.g., 10 kW or more) since this effect becomes significant.

[0104] <Modification> In this embodiment, the main core 211 and the edge cores 212, 213 are made of the same material (electromagnetic steel sheet) as an example. However, the main core 211 and the edge cores 212, 213 do not have to be made of the same material. For example, either the main core 211 or the edge cores 212, 213 may be made of soft magnetic ferrite.

[0105] In addition, in the present embodiment, the bridge cores 220a and 220b are made of soft magnetic ferrite. However, the soft magnetic material constituting the bridge cores 220a and 220b is not limited to soft magnetic ferrite. For example, the bridge cores 220a and 220b may be made of a plurality of electromagnetic steel sheets having the same planar shape (rectangular in the present embodiment) as the shape of the surface parallel to the xy plane of the bridge cores 220a and 220b, and stacked in the z-axis direction. The bridge cores 220a and 220b may be made of a plurality of electromagnetic steel sheets having the same planar shape as the shape of the surface parallel to the yz plane of the bridge cores 220a and 220b, and stacked in the x-axis direction.

[0106] In addition, in this embodiment, the number of the cooling fins 260a-260h and the number of the cooling tubes 270a-270h are 8, respectively. However, these numbers are not limited to 8. Furthermore, the intervals between the cooling fins 260a-260h and the intervals between the cooling tubes 270a-270h do not need to be the same. By increasing the number of the cooling fins 260a-260h and the number of the cooling tubes 270a-270h arranged in the region of the edge cores 212 and 213, the cooling effect of the edge cores 212 and 213 is improved. That is, the number of the cooling fins 260a-260h and the number of the cooling tubes 270a-270h are not limited to the numbers shown in FIG. 1 and FIG. 2, and are appropriately determined according to the temperature required for the induction heating device.

[0107] In addition, in the present embodiment, the case where the number of bridge cores 220a, 220b included in the upper inductor 200 is two has been exemplified. However, the number of bridge cores included in the upper inductor 200 is not limited to two. The number of bridge cores included in the upper inductor 200 may be one, or three or more. For example, one bridge core may be disposed to face at least a partial area of ​​the end face (upper face) on the rear side of the main core 211 and at least a partial area of ​​each of the end faces (upper faces) on the rear sides of the edge cores 212a to 212d and 213a to 213d.

[0108] In the present embodiment, when the shield plates 240a, 240b move to a position closest to the center in the x-axis direction of the induction heating device within the movable range of the shield plates 240a, 240b in the x-axis direction, the end of the core gap region closest to the center of the core gap region that exists in the position facing the bridge cores 220a, 220b (the end of the cooling fins 260d, 260h on the center side of the core gap region in the example shown in FIG. 2) is disposed inside (toward the center of the core gap region) of the shield plates 240a, 240b. However, the positional relationship between the shield plates 240a, 240b and the main core 211 and the partial edge cores 212a-212d, 213a-213d when the shield plates 240a, 240b move to a position closest to the center in the x-axis direction of the induction heating device within the movable range of the shield plates 240a, 240b in the x-axis direction is not limited to such a relationship.

[0109] For example, when the shield plates 240a, 240b move to a position closest to the center position in the x-axis direction of the induction heating device within the movable range of the shield plates 240a, 240b in the x-axis direction, the end portion of at least one of the partial edge cores 212a-212d, 213a-213d on the plate center side may be positioned inside (closer to the plate center) than the shield plates 240a, 240b, respectively. For example, the partial edge cores 212a-212d, 213a-213d may be positioned inside (closer to the plate center) than the shield plates 240a, 240b, respectively.

[0110] Furthermore, when the shield plates 240a, 240b move to a position closest to the center position in the x-axis direction of the induction heating device within the movable range of the shield plates 240a, 240b in the x-axis direction, the end portion of at least one of the cooling fins 260a-260d toward the center of the plate and the end portion of at least one of the cooling fins 260e-260h toward the center of the plate may be positioned more inward (closer to the center of the plate) than the end portion of the shield plates 240a, 240b toward the center of the plate.

[0111] For example, when shield plates 240a, 240b move to a position closest to the center position in the x-axis direction of the induction heating device within the movable range of shield plates 240a, 240b in the x-axis direction, the ends of cooling fins 260d, 260h on the plate center side may be positioned more inward (closer to the plate center) than the ends of shield plates 240a, 240b on the plate center side. Also, the ends of cooling fins 260a-260d, 260e-260h on the plate center side may be positioned more inward (closer to the plate center) than the ends of shield plates 240a, 240b on the plate center side, respectively. .Ma Furthermore, when shield plates 240a, 240b move to a position closest to the center position in the x-axis direction of the induction heating device within the movable range of shield plates 240a, 240b in the x-axis direction, an end portion on the plate center side of at least one of cooling fins 260a-260d and an end portion on the plate center side of at least one of cooling fins 260e-260h may be positioned outside (towards the plate end) of the ends on the plate center side of shield plates 240a, 240b, respectively.

[0112] In addition, in this embodiment, the induction heating device is provided with the shield plates 240a and 240b. However, this is not necessarily required. For example, a secondary coil for adjusting (reducing) the degree of electromagnetic coupling between the coil 230 and the strip steel sheet 100 may be arranged as an example of a shield member at the position where the shield plates 240a and 240b are arranged to prevent overheating of the edge portion of the strip steel sheet 100.

[0113] In addition, the cooling members arranged between the main cores 211, 311 and the partial edge cores 212d, 213d, 312d, 313d and the cooling members arranged between the partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d do not have to be the cooling fins 260a-260h, 360a-360h and the cooling tubes 270a-270h, 370a-370h, as long as they are made of a non-magnetic conductor that can be cooled. For example, a hollow rectangular pipe made of a non-magnetic conductor may be arranged in the area where the cooling fins 260a-260h, 360a-360h and the cooling tubes 270a-270h, 370a-370h are arranged. In this case, cooling water may be supplied to the hollow part of the pipe.

[0114] In addition, cooling members may not be arranged in the regions between the main cores 211, 311 and the partial edge cores 212d, 213d, 312d, 313d and the regions between the partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d. The regions between the main cores 211, 311 and the partial edge cores 212d, 213d, 312d, 313d and the regions between the partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d may be voids. In this case, a cooling gas may be supplied to the voids as a cooling medium. In addition, the length of the voids in the x-axis direction may be made longer than the length shown in FIG. 2 to enhance the cooling effect by air cooling.

[0115] In addition, in the present embodiment, the main core 211 is an integrated single core. However, for example, as shown in FIG. 6, the main core 211 may have a plurality of partial main cores 211a-211b arranged with a gap in the x-axis direction (FIG. 6 is a cross-sectional view corresponding to FIG. 2). In this case, cooling fins 260i and cooling small tubes 270i similar to the cooling fins 260a-260h and cooling small tubes 270a-270h may be arranged between the partial main cores 211a and 211b. Also, as shown in FIG. 6, partial main cores 311a-311b, cooling fins 360i, and cooling small tubes 370i similar to the partial main cores 211a-211b, cooling fins 260i, and cooling small tubes 270i are arranged in the lower inductor 300.

[0116] The number of partial main cores is not limited as long as it is two or more. However, it is preferable that all of the partial main cores can be magnetically coupled to at least one of the bridge cores. It is more preferable that all of the partial main cores are magnetically coupled. FIG. 6 illustrates a case where the partial main cores 211a-211b, 311a-311b and the bridge cores 220c, 320c can be magnetically coupled. FIG. 6 illustrates a case where the bridge core 220c is arranged so that the end face (lower face) of the bridge core 220c on the intended transfer surface CP side contacts the entire end face (upper face) on the rear side of the partial main cores 211a-211b and the entire end face (upper face) on the rear side of the partial edge cores 212a-212d. Similarly, Fig. 6 illustrates an example in which the bridge core 320c is disposed so that the end face (upper face) of the bridge core 320c on the transport intended surface CP side contacts the entire end faces (lower faces) on the rear side of the partial main cores 311a-311b and the entire end faces (lower faces) on the rear side of the partial edge cores 312a-312d. The shapes and sizes of the multiple partial main cores are not limited. The shapes and sizes of the multiple partial main cores may be the same or different. The shapes and sizes of the multiple partial edge cores may also be the same or different.

[0117] In addition, in this embodiment, the case where the original core 210 has the main core 211 and the edge cores 212, 213 is exemplified. That is, the case where the main core 211 and the edge cores 212, 213 are distinguished is exemplified. However, the main core 211 and the edge cores 212, 213 do not necessarily have to be distinguished. For example, the induction heating device may be configured as shown in FIG. 7 and FIG. 8. FIG. 7 is a diagram showing an example of the external configuration of such an induction heating device. FIG. 7 is a diagram corresponding to FIG. 1. FIG. 8 is a diagram showing an example of a first cross section of the induction heating device. Specifically, FIG. 8 is a cross section taken along line II of FIG. 7 and corresponds to FIG. 2.

[0118] 7 and 8, the upper inductor 200 includes an original core 210, a bridge core 220c, a coil 230, and shield plates 240a and 240b. The original core 210 has a plurality of partial original cores 710a-710f arranged with a gap therebetween in the x-axis direction. The partial original cores 710a-710f have different lengths in the x-axis direction compared to the partial edge cores 212a-212d shown in FIG. 2. The other configurations of the partial original cores 710a-710f are the same as those of the partial edge cores 212a-212d. The partial original cores 710a-710f are, for example, a plurality of electromagnetic steel sheets stacked in the x-axis direction, and are composed of a plurality of electromagnetic steel sheets having the same thickness and the same planar shape. In this case, the number of stacked electromagnetic steel sheets that constitute the partial original cores 710a-710f is different from the number of stacked electromagnetic steel sheets that constitute the partial edge cores 212a-212d shown in FIG. 2.

[0119] The yz cross section of the partial original cores 710a-710f is the same as the cross section shown in Fig. 4. Figs. 7 and 8 illustrate a case where all the partial original cores 710a-710f, 810a-810f have the same shape and size. Therefore, when the partial original cores 710a-710f and the partial original cores 810a-810f are made of electromagnetic steel sheets having the same thickness and the same planar shape, the number of laminated electromagnetic steel sheets in each is the same. Figs. 7 and 8 illustrate a case where the intervals between the partial original cores 710a-710f and the intervals between the partial original cores 810a-810f in the x-axis direction are the same.

[0120] The bridge core 220c is a ferromagnetic material that allows at least one of the partial original cores 710a to 710f to be magnetically coupled. The bridge core 220c itself is the same as the bridge core 220c shown in FIG. 6. FIGS. 7 and 8 show an example in which the end face (lower face) of the bridge core 220c on the intended transfer surface CP side faces the entire end faces (upper faces) of the partial original cores 710a to 710f on the rear side with a gap between them. The gap between the bridge core 220c and the partial original cores 710a to 710f is set so that the bridge core 220c is coupled to at least one of the partial original cores 710a to 710f. core The intervals between the partial original cores 710a to 710f are determined so that the bridge core 220c can be magnetically coupled to all of the partial original cores 710a to 710f.

[0121] Like the upper inductor 200, the lower inductor 300 includes an original core 310 having partial original cores 810a to 810f, a bridge core 320c, a coil 330, and shield plates 340a and 340b, and has the same configuration as the upper inductor 200.

[0122] 7 and 8, a cooling member (e.g., a cooling fin and a cooling tube) may be disposed between two adjacent partial original cores (e.g., partial original cores 710a and 710b) spaced apart in the x-axis direction, as described in this embodiment. In addition, the original cores 210 and 310 may be in contact with the bridge cores 220c and 320c, as described in this embodiment.

[0123] It should be noted that each of the above modifications may be adopted in the lower inductor 300. Various modified examples of this embodiment have been described above. A modified example that combines at least two of the modified examples, including the modified examples of this embodiment described before the description of the <Modified Examples> section, may be adopted in the induction heating device of this embodiment.

[0124] Second embodiment Next, a second embodiment of the present invention will be described. In the first embodiment, the original core 210 (main core 211 and edge cores 212, 213) and the bridge cores 220a, 220b are configured as separate cores. Similarly, the original core 310 (main core 311 and edge cores 312, 313) and the bridge cores 320a, 320b are configured as separate cores. In contrast, in this embodiment, the original core and the bridge core are configured as one integrated core. Thus, the main difference between this embodiment and the first embodiment is the core configuration. Therefore, in the description of this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals as those in Figs. 1 to 8, and detailed description thereof will be omitted.

[0125] 9 is a diagram showing an example of the external configuration of an induction heating device, and corresponds to FIG. The induction heating device shown in FIG. 9 includes an upper inductor 900 and a lower inductor 1000. The upper inductor 900 and the lower inductor 1000 are disposed at positions facing each other across the intended transport surface CP of the steel strip 100 (see FIGS. 10 to 13). The upper inductor 900 and the lower inductor 1000 have the same configuration. Therefore, the upper inductor 900 will be described in detail here, and a detailed description of the lower inductor 1000 will be omitted as necessary. Note that the interval between the upper inductor 900 and the intended transport surface CP and the interval between the lower inductor 1000 and the intended transport surface CP may or may not be the same. In the present embodiment, as in the first embodiment, a case is illustrated in which the induction heating device has a shape that is mirror symmetrical with the yz plane at the center of the x-axis direction of the induction heating device as the plane of symmetry. Furthermore, when the distance between the upper inductor 900 and the strip steel plate 100 is the same as the distance between the lower inductor 1000 and the strip steel plate 100, the induction heating device has a shape that is mirror symmetric with respect to the xy plane at the center of the induction heating device in the z-axis direction.

[0126] FIG. 10 is a diagram showing an example of a first cross section of the induction heating device. Specifically, FIG. 10 is a cross section taken along line II of FIG. 9, and corresponds to FIG. 2. FIG. 11 is a diagram showing an example of a second cross section of the induction heating device. Specifically, FIG. 11 is a cross section taken along line II-II of FIG. 9, and corresponds to FIG. 3. FIG. 12 is a diagram showing an example of a third cross section of the induction heating device. Specifically, FIG. 12 is a cross section taken along line III-III of FIG. 9, and corresponds to FIG. 4. FIG. 13 is a diagram showing an example of a fourth cross section of the induction heating device. Specifically, FIG. 13 is a cross section taken along line IV-IV of FIG. 9.

[0127] In FIG. 10, the upper inductor 900 includes an upper core 910, a coil 230, shield plates 240a to 240b, cooling fins 260a to 260h, and cooling tubes 270a to 270h.

[0128] The upper core 910 is configured as a single core by integrating the original core 210 and the bridge core 220 described in the first embodiment. In the present embodiment, a case will be illustrated in which the upper core 910 is made up of a plurality of electromagnetic steel plates that are stacked in the x-axis direction and have the same thickness.

[0129] 10, regions 911a and 911b of upper core 910 include regions corresponding to bridge cores 220a and 220b of the first embodiment among the regions of upper core 910. In this embodiment, the shapes of the electromagnetic steel sheets arranged in regions 911a and 911b of upper core 910 differ between a region adjacent in the z-axis direction to the region where cooling fins 260a-260h and cooling tubes 270a-270h are arranged and the other regions.

[0130] In FIG. 10, in the regions 911a and 911b of the upper core 910, adjacent in the z-axis direction to the region in which the cooling fins 260a-260h and the cooling tubes 270a-270h are arranged, for example, flat electromagnetic steel sheets corresponding to the region are laminated in the x-axis direction. The yz cross section of the region is, for example, like the yz cross section of the upper core 910 shown in FIG. 11. FIG. 11 illustrates a case in which the overall outer shape of the yz cross section of the region is rectangular. FIG. 11 also illustrates a case in which the length of the rectangle in the z-axis direction is the same as the length of the bridge cores 220a and 220b of the first embodiment in the z-axis direction. However, the length of the rectangle in the z-axis direction may be (slightly) different for each position in the x-axis direction depending on, for example, the curvature of the cooling tubes 270a-270h.

[0131] On the other hand, in Fig. 10, in the regions 911a and 911b of the upper core 910, other than the region adjacent in the z-axis direction to the region in which the cooling fins 260a-260h and the cooling tubes 270a-270h are arranged, electromagnetic steel sheets having the same planar shape corresponding to the region are laminated in the x-axis direction, for example. The yz cross section of the region is, for example, like the yz cross section of the upper core 910 shown in Fig. 13. Fig. 13 illustrates a case where the overall outer shape of the yz cross section of the region is E-shaped (however, in the example shown in Fig. 13, the horizontal lines of E all have the same length). Fig. 13 also illustrates a case where the length in the z-axis direction of the region (the length in the direction parallel to the horizontal lines of E) is the sum of the length in the z-axis direction of the bridge cores 220a and 220b of the first embodiment and the length in the z-axis direction of the original core 210 (main core 211, edge cores 212 and 213) of the first embodiment.

[0132] 10, the region 912 of the upper core 910 does not include the regions corresponding to the bridge cores 220a and 220b of the first embodiment. In the region 912 of the upper core 910, for example, electromagnetic steel sheets having the same planar shape corresponding to the region 912 are laminated in the x-axis direction. The yz cross section of the region 912 of the upper core 910 is, for example, like the yz cross section of the upper core 910 shown in FIG. 12. FIG. 12 illustrates a case where the outer shape of the entire yz cross section of the region 912 of the upper core 910 is E-shaped (however, in the example shown in FIG. 12, all the horizontal lines of E have the same length). Also, FIG. 12 illustrates a case where the length in the z-axis direction of the region 912 of the upper core 910 (the length in the direction parallel to the horizontal lines of E) is the same as the length in the z-axis direction of the original core 210 (the main core 211, the edge cores 212 and 213) of the first embodiment.

[0133] The multiple electromagnetic steel sheets constituting the upper core 910 are fixed so as not to separate from each other. The method of fixing the multiple electromagnetic steel sheets is not limited. For example, various known methods such as fixing with an adhesive, fixing by welding, fixing by crimping, and fixing using a fixing member are adopted as a method of fixing the multiple electromagnetic steel sheets. As described above, in this embodiment, the original core (main core and edge core) and the bridge core are one integrated core. Therefore, as shown in FIG. 9 and FIG. 10, there is no boundary line between the bridge core (region corresponding to bridge cores 220a, 220b) and the main core and edge core (region corresponding to main core 211 and edge cores 212, 213). For convenience of notation, the boundary lines of the individual electromagnetic steel sheets are omitted in FIG. 10.

[0134] In this embodiment, a bridge core is configured by the regions of the upper core 910 and the lower core 1010 that correspond to the bridge cores 220a, 220b, 320a, and 320b. In this embodiment, the regions of the upper core 910 and the lower core 1010 that correspond to the main cores 211 and 311 and the edge cores 212 to 213 and 312 to 313 are configured by the regions of the upper core 910 and the lower core 1010. In the region A case where a partial core is formed will be illustrated.

[0135] 12 and 13 show regions 9110 and 10110 corresponding to the main cores 211 and 311. Also, Fig. 13 shows regions 9120 and 10120 corresponding to the bridge cores 220a, 220b, 320a and 320b. 12 and 13, the regions 9110, 10110 corresponding to the main cores 211, 311 have body portions 9111, 10111, central legs 9112, 10112, upstream legs 9113, 10113, and downstream legs 9114, 10114. The body portions 9111, 10111, the central legs 9112, 10112, the upstream legs 9113, 10113, and the downstream legs 9114, 10114 are the same as the body portions 2111, 3111, the central legs 2112, 3112, the upstream legs 2113, 3113, and the downstream legs 2114, 3114, respectively (see FIGS. 3 and 4).

[0136] The overall outline of a cross section cut along the yz plane of the regions corresponding to the edge cores 212-213, 312-313 is the same as the overall outline of a cross section cut along the yz plane of the regions 9110, 10110 corresponding to the main cores 211, 311. Therefore, like the regions 9110, 10110 corresponding to the main cores 211, 311, the regions corresponding to the edge cores (partial edge cores) also have a body portion, a central leg portion, an upstream leg portion, and a downstream leg portion.

[0137] Like the upper inductor 900, the lower inductor 1000 also includes a lower core 1010, a coil 330, shield plates 340a and 340b, cooling fins 360a to 360h, and cooling tubes 370a to 370h, and has the same configuration as the upper inductor 900.

[0138] As described above, in this embodiment, the regions corresponding to the bridge cores 220a, 220b, 320a, and 320b are integrated with the regions corresponding to the original cores 210 and 320 without being separated. That is, in this embodiment, the original core and the bridge core are one core (one upper core 910 and one lower core 1010). By doing so, an induction heating device having the effects described in the first embodiment is realized. In addition, it is possible to further increase the coupling (spin-spin coupling) between the spins of the constituent atoms in the regions corresponding to the bridge cores 220a and 220b and the spins of the constituent atoms in the region corresponding to the original core 210. As a result, it is possible to increase the magnetic flux density generated in these regions by passing an AC current through the coil 230 compared to the case where the original core 210 and the bridge cores 220a and 220b are separate cores.

[0139] As in the first embodiment, in this embodiment as well, the cooling fins 260a to 260h and the cooling tubes 270a to 270h can suppress an increase in temperature of the upper core 910. The above also applies to the lower inductor 1000.

[0140] As described above, in this embodiment as well, as in the first embodiment, an induction heating device can be provided that can simultaneously suppress the core temperature below a desired temperature and generate an alternating magnetic field of a desired magnitude.

[0141] As is clear from the above description, the configuration of this embodiment is obtained by replacing the original core, main core, edge core, bridge core, and partial edge core described in the first embodiment with a region corresponding to the original core, a region corresponding to the main core, a region corresponding to the edge core, a region corresponding to the bridge core, and a region corresponding to the partial edge core, respectively. Therefore, by making such replacements and reinterpreting the description of the first embodiment, the following preferred ranges are determined.

[0142] A preferred range of the lap length L on the plate center side of the region corresponding to the bridge cores 220a and 220b (L≧α, etc.) A preferred range of the lap length L' on the plate end side of the region corresponding to the bridge cores 220a and 220b (L'≧α, etc.) A preferred range of the height H of the region corresponding to the bridge cores 220a and 220b (H≧Min(0.5×h, 0.5×α), etc.) A preferred range of the ratio of the length BL in the y-axis direction of the region corresponding to the bridge cores 220a and 220b to the length CL in the y-axis direction of the region corresponding to the main core 211 and the partial edge cores 212a to 212d, 213a to 213d (BL / CL≧0.2, etc.)

[0143] <Modification> In the present embodiment, the shape of the region 912 of the upper core 910 is a rectangular parallelepiped. However, the shape of the region 912 of the upper core 910 is not limited to a rectangular parallelepiped. For example, as shown in FIG. 14, one or more recesses may be formed on the end face (lower face) of the region 912 of the upper core 910 on the transfer planned surface CP side (note that FIG. 14 is a cross-sectional view corresponding to FIG. 10). FIG. 14 illustrates a case where two recesses are formed in the region 912 of the upper core 910 with an interval in the x-axis direction. Also, as shown in FIG. 14, cooling fins 260j-260k and cooling tubes 270j-270k similar to the cooling fins 260a-260h and cooling tubes 270a-270h may be arranged in the recesses. 14 illustrates an example in which the height (length in the z-axis direction) of the cooling fins 260j-260k is lower than the height of the cooling fins 260a-260h so that the cooling pipes 270j-270k do not reach the end face (upper face) on the rear side of the region 912. In this way, it is possible to both arrange the cooling fins 260j-260k and the cooling pipes 270j-270k in the region 912 of the upper core 910 and to integrate the regions 911a, 911b and the region 912 into a single core.

[0144] 14, cooling fins 360j-360k and cooling small pipes 370j-370k similar to cooling fins 360a-360h and cooling small pipes 370a-370h may be arranged on the lower core 1010. Fig. 14 illustrates a case where the height (length in the z-axis direction) of cooling fins 360j-360k is shorter than the height of cooling fins 360a-360h, similar to cooling fins 260j-260k.

[0145] Furthermore, the yz cross section at the position where the cooling fins 260j-260k, 360j-360k and the cooling tubes 270j-270k, 370j-370k are arranged is a cross section obtained by changing the z-axis length of the cooling fins 260a, 360a, upper core 910, and lower core 1010 in Figure 11 to the z-axis length of the cooling fins 260j-260k, 360j-360k, upper core 910, and lower core 1010 at the position where the cooling fins 260j-260k, 360j-360k and the cooling tubes 270j-270k, 370j-370k are arranged.

[0146] Furthermore, in this embodiment, a case has been exemplified in which the height (length in the z-axis direction) of region 912 of upper core 910 is lower than the height of other regions of upper core 910. However, this is not necessarily the case. For example, as shown in FIG. 15, the height (length in the z-axis direction) of upper core 910 may be the same regardless of the position in the x-axis direction. FIG. 15 illustrates a case in which the entire region 911c in the x-axis direction of upper core 910 includes a region corresponding to a bridge core (note that FIG. 15 is a cross-sectional view corresponding to FIG. 10). The above modifications may be adopted in the lower inductor 1000.

[0147] In addition, the various modified examples described in the first embodiment may be adopted in the induction heating device of this embodiment. In addition, a modified example that combines at least two of the modified examples described above, including the modified examples described in the first embodiment, may be adopted in the induction heating device of this embodiment.

[0148] Third embodiment Next, a third embodiment of the present invention will be described. In the first embodiment, a case where non-magnetic conductors configured to be able to be cooled are arranged between the main core 211 and the edge cores 212, 213 and between the partial edge cores 212a-212d, 213a-213d adjacent to each other is illustrated. In the present embodiment, in addition to this, a case where non-magnetic conductors configured to be able to be cooled are arranged on the end faces (upper and lower faces) on the rear side of the bridge cores 220a-220b, 320a-320b is illustrated. In this way, the temperature of the bridge cores 220a-220b, 320a-320b can be further reduced. In this manner, in the present embodiment, a configuration for reducing the temperature of the bridge cores 220a-220b, 320a-320b is added to the induction heating device of the first embodiment. Therefore, in the description of this embodiment, the same reference numerals as those in the first and second embodiments are used to omit detailed description thereof.

[0149] Fig. 16 is a diagram showing an example of a first cross section of an induction heating device, and corresponds to Fig. 2. Fig. 17 is a diagram showing an example of a second cross section of an induction heating device, and corresponds to Fig. 3. In the present embodiment, as in the first embodiment, an example is shown in which the induction heating device has a shape that is in a mirror symmetric relationship with the yz plane at the center of the x-axis direction of the induction heating device as the plane of symmetry. 16 and 17 illustrate an example in which cooling pipes 1610a and 1610b are arranged on end faces (upper faces) on the rear side of bridge cores 220a and 220b of an upper inductor 1600. Similarly, Fig. 16 and 17 illustrate an example in which cooling pipes 1710a and 1710b are arranged on end faces (lower faces) on the rear side of bridge cores 320a and 320b of a lower inductor 1700. In addition, in this embodiment, an example in which the external shape of the cooling pipes 1610a, 1610b, 1710a, and 1710b is a zigzag shape is illustrated.

[0150] The cooling pipes 1610a and 1610b are arranged so as to be zigzag on the end faces (upper faces) on the rear side of the bridge cores 220a and 220b. The cooling pipes 1610a and 1610b are in contact with the bridge cores 220a and 220b. The cooling pipes 1610a and 1610b are made of a nonmagnetic conductor such as copper. Similarly, the cooling pipes 1710a and 1710b are arranged so as to be zigzag on the end faces (lower faces) on the rear side of the bridge cores 320a and 320b. The cooling pipes 1710a and 1710b are in contact with the bridge cores 320a and 320b. 71 00a, 1 71 0b is also made of a non-magnetic conductor such as copper.

[0151] In the configuration of the first embodiment, for example, the cooling tubes 270a to 270h and air cooling can suppress the temperature rise of the bridge cores 220a and 220b. However, in such a configuration, for example, when the temperature around the induction heating device is high, there is a risk that the temperature of the bridge cores 220a and 220b cannot be lowered to a desired temperature. In contrast, in this embodiment, the cooling tubes 1610a and 1610b are arranged on the end faces (upper faces) on the rear side of the bridge cores 220a and 220b. Therefore, the temperature of the bridge cores 220a and 220b can be lowered more than in the configuration of the first embodiment. In this way, in addition to the effects described in the first embodiment, this embodiment has the effect of reliably lowering the temperature of the bridge cores 220a and 220b. The above also applies to the lower inductor 1700.

[0152] <Modification> In the present embodiment, the cooling pipes 1610a and 1610b are used as an example of the cooling member for cooling the bridge cores 220a and 220b. However, the cooling member for cooling the bridge cores 220a and 220b is not limited to such a cooling member. For example, the cooling member for cooling the bridge cores 220a and 220b may be a plate-shaped non-magnetic conductor. In this case, the plate-shaped non-magnetic conductor may be cooled by thermal conduction.

[0153] In the present embodiment, the cooling pipes 1610a and 1610b are added to the induction heating device of the first embodiment. However, the cooling pipes 1610a and 1610b may be added to the induction heating device of the second embodiment. The above modifications may be adopted in the lower inductor 1700. In addition, the various modified examples described in the first and second embodiments may be employed in the induction heating device of this embodiment. In addition, a modified example that combines at least two of the modified examples described above, including the modified examples described in the first and second embodiments, may be employed in the induction heating device of this embodiment.

[0154] (Fourth embodiment) Next, the fourth embodiment will be described. In the first embodiment, the case where the distance (distance in the z-axis direction) between the tip surfaces of the central leg, upstream leg, and downstream leg of the original core 210, 310 (main core 211, 311 and partial edge cores 212a-212d, 213a-213d, 312a-312d, 313a-313d) and the transport planned surface CP is the same is illustrated. In contrast, in the present embodiment, the case where the distance between the tip surface of the central leg of the original core and the transport planned surface CP is shorter than the distance between the area of ​​the original core other than the central leg and the transport planned surface CP is illustrated. Thus, the present embodiment and the first to third embodiments are mainly different in the configuration of the original core. Therefore, in the description of this embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals as those in Figs. 1 to 8, and detailed description thereof will be omitted.

[0155] Fig. 18 is a diagram showing an example of the external configuration of an induction heating device, and corresponds to Fig. 1. The induction heating device shown in Fig. 18 includes an upper inductor 1800 and a lower inductor 1900. The upper inductor 1800 and the lower inductor 1900 are disposed in positions facing each other across the intended transport surface CP of the steel strip 100 (see Figs. 19 to 21). The upper inductor 1800 and the lower inductor 1900 have the same configuration. Therefore, here, the upper inductor 1800 will be described in detail, and a detailed description of the lower inductor 1900 will be omitted as necessary.

[0156] The distance between the upper inductor 1800 and the intended transport surface CP and the distance between the lower inductor 1900 and the intended transport surface CP may or may not be the same. As in the first embodiment, the present embodiment illustrates a case in which the induction heating device has a shape that is in a mirror symmetrical relationship with the yz plane at the center of the x-axis direction of the induction heating device as the plane of symmetry. When the distance between the upper inductor 1800 and the intended transport surface CP and the distance between the lower inductor 1900 and the intended transport surface CP are the same, the induction heating device has a shape that is in a mirror symmetrical relationship with the intended transport surface CP as the plane of symmetry.

[0157] Fig. 19 is a diagram showing an example of a first cross section of the induction heating device. Specifically, Fig. 19 is a cross section taken along line II in Fig. 18, and corresponds to Fig. 2. Fig. 20 is a diagram showing an example of a second cross section of the induction heating device. Specifically, Fig. 20 is a cross section taken along line II-II in Fig. 18, and corresponds to Fig. 3. Fig. 21 is a diagram showing an example of a third cross section of the induction heating device. Specifically, Fig. 21 is a cross section taken along line III-III in Fig. 18, and corresponds to Fig. 4.

[0158] 18 and 19, an upper inductor 1800 includes an original core 1810, bridge cores 1820a to 1820b, a coil 1830, shield plates 1840a to 1840b, cooling fins 1860a to 1860h, and cooling tubes 1870a to 1870h. The original core 1810 has a main core 1811 and edge cores 1812 and 1813. The main core 1811 and the edge cores 1812 and 1813 are arranged with a gap between them in the x-axis direction.

[0159] The main core 1811 is a ferromagnetic body that is disposed at a position closest to the center of the induction heating device in the x-axis direction among the main core 1811 and the edge cores 1812 and 1813. The edge cores 1812 and 1813 are ferromagnetic bodies that are disposed closer to the end of the original core 1810 in the x-axis direction than the main core 1811. The edge cores 1812 and 1813 have a plurality of partial edge cores 1812a to 1812d and 1813a to 1813d. The plurality of partial edge cores 1812a to 1812d and 1813a to 1813d are disposed with a gap therebetween in the x-axis direction. In addition, the partial edge cores 1812d and 1813d that are closest to the main core 1811 among the plurality of partial edge cores 1812a to 1812d and 1813a to 1813d and the main core 1811 are also disposed with a gap therebetween in the x-axis direction.

[0160] In this embodiment, the main core 1811 is formed of a plurality of electromagnetic steel sheets stacked in the x-axis direction, each having the same thickness and planar shape. Similarly, in this embodiment, the edge cores 1812, 1813 (partial edge cores 1812a-1812d, 1813a-1813d) are formed of a plurality of electromagnetic steel sheets stacked in the x-axis direction, each having the same thickness and planar shape. In addition, in this embodiment, the thickness and planar shape of the electromagnetic steel sheets that constitute the main core 1811 are the same as those of the electromagnetic steel sheets that constitute the edge cores 1812, 1813. In addition, in this embodiment, the number of laminated electromagnetic steel sheets that constitute the main core 1811 is different from the number of laminated electromagnetic steel sheets that constitute the edge cores 1812, 1813 (partial edge cores 1812a-1812d, 1813a-1813d).

[0161] The electromagnetic steel sheets constituting the main core 1811 are fixed so as not to separate from each other. The electromagnetic steel sheets constituting each of the partial edge cores 1812a to 1812d and 1813a to 1813d are also fixed so as not to separate from each other. The method of fixing the electromagnetic steel sheets is not limited. For example, various known methods such as fixing with an adhesive, fixing by welding, fixing by crimping, and fixing using a fixing member are adopted as the method of fixing the electromagnetic steel sheets. The thickness and planar shape of the electromagnetic steel sheets constituting the main core 1811 and the thickness and planar shape of the electromagnetic steel sheets constituting the edge cores 1812 and 1813 do not need to be the same. For convenience of notation, the boundary lines of the individual electromagnetic steel sheets are omitted in FIG. 19. In this embodiment, main cores 1811 and 1911 and edge cores 1812 to 1813 and 1912 to 1913 (plurality of partial edge cores 1812a to 1812d, 1813a to 1813d, 1912a to 1912d, and 1913a to 1913d) are used. thing Hereinafter, a partial core is configured as follows.

[0162] As shown in Fig. 21, the main cores 1811, 1911 have body sections 18111, 19111 and central legs 18112, 19112. Fig. 21 illustrates an example in which the body section 18111 and the central leg section 18112 are integrated. Similarly, Fig. 21 illustrates an example in which the body section 19111 and the central leg section 19112 are also integrated. As described above, the two-dot chain lines indicating the body sections 18111, 19111 and the central legs 18112, 19112 are imaginary lines.

[0163] The body portions 18111, 19111 are respectively provided on the rear side of the coils 1830, 1930, extending in a direction parallel to the conveying direction (y-axis direction) from a region upstream of the coils 1830, 1930 (positive side of the y-axis) to a region downstream of the coils 1830, 1930 (negative side of the y-axis).

[0164] The central legs 18112 and 19112 are connected to the body portions 18111 and 18112 so as to pass through the hollow portions of the coils 1830 and 1930, respectively. 9111 in the direction of the planned transfer surface CP. The positions of the central legs 18112, 19112 in the y-axis direction preferably include the positions of the axial centers of the coils 1830, 1930 in the y-axis direction. In other words, it is preferable that the y coordinates of the central legs 18112, 19112 overlap with the y coordinates of the axial centers of the coils 1830, 1930. In this embodiment, the positions (xy coordinates) of the centers of gravity of the central legs 18112, 19112 in the xy plane and the axial positions (xy coordinates) of the coils 1830, 1930 are included in the y-axis direction of the central legs 18112, 19112. 9 30 coincides with the position (xy coordinates) of the axis of the

[0165] Central legs 18112 and 19112 are teeth of the core. The tip surfaces of central legs 18112 and 19112 are pole faces. Body parts 18111 and 19111 are yokes of the core.

[0166] The overall outer shape of the yz cross section of edge cores 1812, 1813, 1912, and 1913 is the same as the overall outer shape of the yz cross section of main cores 1811 and 1911 shown in Fig. 21. In Fig. 21, (1812, 1813) and (1912, 1913) suffixed to 1811 and 1911 indicate this.

[0167] Therefore, the edge cores 1812, 1813, 1912, 1913 (partial edge cores 1812a-1812d, 1813a-1813d, 1912a-1912d, 1913a-1913d) also have a body, a central leg, an upstream leg, and a downstream leg, similar to the main cores 1811, 1911. The lengths in the y-axis and z-axis directions of the body, the lengths in the y-axis and z-axis directions of the central leg, the lengths in the y-axis and z-axis directions of the upstream leg, and the lengths in the y-axis and z-axis directions of the downstream leg are the same for the main cores 1811, 1911 and the partial edge cores 1812a-1812d, 1813a-1813d, 1912a-1912d, 1913a-1913d. On the other hand, the x-axis length of the body, the x-axis length of the central leg, the x-axis length of the upstream leg, and the x-axis length of the downstream leg are longer in the main cores 1811 and 1911 than the partial edge cores 1812a-1812d, 1813a-1813d, 1912a-1912d, and 1913a-1913d.

[0168] The overall outer shape of the yz cross section of the bridge cores 1820b, 1920a to 1920b is the same as the overall outer shape of the yz cross section of the bridge cores 1820a, 1920a (see FIG. 20).

[0169] As described above, the shape of the surface of the main core 1811 parallel to the yz plane and the shape of the surfaces of the edge cores 1812 and 1813 parallel to the yz plane are each T-shaped (see the outlines of the main cores 1811 and 1811 shown in FIG. 21). That is, the main core 1811 and the edge cores 1812 and 1813 are so-called T-shaped cores. In contrast, the main core 211 and the edge cores 212 and 213 of the first embodiment are so-called E-shaped cores. Therefore, the main core 1811 and the edge cores 1812 and 1813 do not have the upstream leg and downstream leg that the main core 211 and the edge cores 212 and 213 have. This is what makes the main core 211 and the edge cores 1812 and 1813 of the first embodiment different from the main core 1811 and the edge cores 1812 and 1813 of this embodiment.

[0170] The coil 1830 is a conductor having a winding portion. In FIG. 18, a case is illustrated in which the thick portion (a portion other than the straight line extending from the AC power source 400) is the winding portion of the coil 1830. The winding portion of the coil 1830 is disposed in the xy plane so as to pass through the slot of the original core 1810 and wind around the central leg of the original core 1810 in a racetrack shape. The size of the plane parallel to the xy plane of the coil 230 of the first embodiment is determined according to the size of the slot of the original core 210. In contrast, the size of the plane parallel to the xy plane of the coil 1830 of this embodiment is determined according to the size of the slot of the original core 1810. This is what makes the coil 230 of the first embodiment different from the coil 1830 of this embodiment. As shown in FIG. 18 and FIG. 19, the length of the winding portion of the coils 1830 and 1930 in the x-axis direction is longer than the width of the strip steel plate 100 (the intended conveyance surface CP). Moreover, both ends in the x-axis direction of the winding parts of the coils 1830 and 1930 are located outside both ends in the x-axis direction of the steel strip 100 (the conveyance surface CP). The coil 1830 may have an insulator disposed around the conductor.

[0171] 18, the coils 1830 and 1930 are electrically connected to an AC power supply 400. As shown in FIG. 18, in this embodiment, one end 1831 of the winding portion of the coil 1830 is electrically connected to one terminal 401 of the two output terminals of the AC power supply 400. In addition, the other end 1832 of the winding portion of the coil 1830 is electrically connected to the other terminal 402 of the two output terminals of the AC power supply 400.

[0172] Moreover, of the two ends of the winding portion of coil 1930, one end 1931 located opposite one end 1831 of the winding portion of coil 1830 in the z-axis direction is electrically connected to one terminal 401 of the two output terminals of AC power supply 400. Moreover, of the two ends of the winding portion of coil 1930, the other end 1932 located opposite the other end 1832 of coil 1830 in the z-axis direction is electrically connected to the other terminal 402 of the two output terminals of AC power supply 400.

[0173] In this manner, in this embodiment, the coils 1830 and 1930 are connected in parallel to the AC power supply 400 such that the winding directions of the coils 1830 and 1930 are in the same direction when viewed from the AC power supply 400.

[0174] Therefore, as shown in FIG. 18, when viewed from the same viewpoint at the same time, the directions of the alternating currents flowing in the opposing regions of coils 1830 and 1930 are the same (see the arrows shown within coils 1830 and 1930 in FIG. 18).

[0175] 19 to 21 show an example in which the end of the coil 1830 on the intended transport surface CP side is closer to the strip-shaped steel plate 100 than the tip surface (the surface located closest to the intended transport surface CP) of the original core 1810. However, the end of the coil 1830 on the intended transport surface CP side and the tip surface of the original core 1810 may be substantially flush with each other.

[0176] 19, cooling fins 1860a, 1860b, 1860c, and 1860d are respectively arranged between the partial edge cores 1812a and 1812b, between the partial edge cores 1812b and 1812c, between the partial edge cores 1812c and 1812d, and between the partial edge core 1812d and the main core 1811. Similarly, cooling fins 1860a, 1860b, 1860c, and 1860d are respectively arranged between the partial edge cores 1813a and 1813b, between the partial edge cores 1813b and 1813c, between the partial edge cores 1813c and 1813d, between the partial edge core 1813d and the main core 1811. 18 Cooling fins 1860e, 1860f, 1860g, and 1860h are disposed between the cooling fins 1860e, 1860f, 1860g, and 1860h, respectively. In this embodiment, as in the first embodiment, the spacing between these is fixed (not changeable). However, the spacing between these may be changeable.

[0177] The cooling fins 1860a to 1860h are an example of a cooling member for cooling the main core 1811 and the partial edge cores 1812a to 1812d and 1813a to 1813d. In the present embodiment, similarly to the first embodiment, the cooling fins 1860a to 1860h are fin-shaped non-magnetic conductive plates. The cooling fins 1860a to 1860h are made of, for example, a copper plate.

[0178] The cooling fins 1860a-1860h are fitted with cooling pipes 1870a-1870h. The cooling pipes 1870a-1870h are an example of a cooling member for cooling the main core 1811, the partial edge cores 1812a-1812d, 1813a-1813d, and the bridge cores 1820a, 1820b. In the present embodiment, as in the first embodiment, the cooling pipes 1870a-1870h are non-magnetic conductive pipes.

[0179] The cooling fins 1860a to 1860h and the cooling tubes 1870a to 1870h attached thereon are in contact with each other. 18 70a~ 18 20 and 21 show an example in which the overall shape of the yz cross section of the region including the cooling fins 1860a and the cooling pipe 1870a is the same as the overall shape of the yz cross section of the original core 1810 (main core 1811 and partial edge cores 1812a-1812d, 1813a-1813d). That is, Fig. 20 and Fig. 21 show an example in which the overall shape and size of the region of the cooling fins 1860a and the cooling pipe 1870a in Fig. 20 are the same as the shape and size of the main core 1811 in Fig. 21. A cooling medium such as cooling water is supplied to the inside of the cooling pipes 1870a-1870h, similar to the cooling pipes 270a-270h.

[0180] As shown in FIG. 3 and FIG. 4, the overall yz cross section of the main core 211 of the first embodiment has an E-shape. The overall yz cross section of the region including the cooling fins 260a-260h and the cooling tubes 270a-270h attached thereon is also an E-shape. The overall yz cross section of the partial edge cores 212a-212d and 213a-213d of the first embodiment is also an E-shape. In contrast, as shown in FIG. 20 and FIG. 21, the overall yz cross section of the main core 1811 of this embodiment has a T-shape. The overall yz cross section of the region including the cooling fins 1860a-1860h and the cooling tubes 1870a-1870h attached thereon is also a T-shape. The overall yz cross section of the partial edge cores 1812a-1812d and 1813a-1813d of this embodiment is also a T-shape. This is what distinguishes the main core 211, edge cores 212, 213, cooling fins 260a-260h, and cooling tubes 270a-270h of the first embodiment from the main core 1811, edge cores 1812, 1813, cooling fins 1860a-1860h, and cooling tubes 1870a-1870h of this embodiment.

[0181] As in the first embodiment, in this embodiment as well, the cooling members arranged between the main cores 1811, 1911 and the partial edge cores 1812d, 1813d, 1912d, 1913d and between the partial edge cores 1812a-1812d, 1813a-1813d, 1912a-1912d, 1913a-1913d do not have to be the cooling fins 1860a-1860h, 1960a-1960h and the cooling tubes 1870a-1870h, 1970a-1970h, as long as they are made of non-magnetic conductors configured to be able to be cooled. In addition, cooling members may not be arranged in the regions between the main cores 1811, 1911 and the partial edge cores 1812d, 1813d, 1912d, 1913d and the regions between the partial edge cores 1812a to 1812d, 1813a to 1813d, 1912a to 1912d, 1913a to 1913d. The regions between the main cores 1811, 1911 and the partial edge cores 1812d, 1813d, 1912d, 1913d and the regions between the partial edge cores 1812a to 1812d, 1813a to 1813d, 1912a to 1912d, 1913a to 1913d may be voids. In addition, the length of the void region in the x-axis direction may be made longer than the length shown in FIG. 19 to enhance the cooling effect by air cooling.

[0182] The shield plates 1840a and 1840b are an example of a shield member for preventing overheating of the edge portion of the strip steel plate 100 by adjusting (reducing) the degree of electromagnetic coupling between the coil 1830 and the strip steel plate 100. The size of the surface parallel to the xy plane of the shield plates 240a and 240b of the first embodiment is determined according to the size of the surface parallel to the xy plane of the original core 210. In contrast, the size of the surface parallel to the xy plane of the shield plates 1840a and 1840b of the present embodiment is determined according to the size of the surface parallel to the xy plane of the original core 1810. This is different between the shield plates 240a and 240b of the first embodiment and the shield plates 1840a and 1840b of the present embodiment. Therefore, the shield plates 1840a and 1840b may also move in the x-axis direction within their movable range, similar to the shield plates 240a and 240b of the first embodiment. Also, as in the first embodiment, when the amount of meandering of the strip steel plate 100 exceeds the order of centimeters, it is preferable to move the entire induction heating device (upper inductor 1800 and lower inductor 1900) in the x-axis direction (the direction in which the strip steel plate 100 meanders) by an amount equal to the amount of meandering of the strip steel plate 100.

[0183] The bridge cores 1820a and 1820b are ferromagnetic bodies that can be magnetically coupled to at least one of the main core 1811 and the partial edge cores 1812a to 1812d and 1813a to 1813d. As in the first embodiment, the present embodiment illustrates a case in which the bridge cores 1820a and 1820b have soft magnetic ferrite (a ferromagnetic body with no anisotropy in the magnetization direction). As in the first embodiment, the present embodiment illustrates a case in which the bridge core 1820a can be magnetically coupled to the main core 1811 and the partial edge cores 1812a to 1812d, and the bridge core 1820b can be magnetically coupled to the main core 1811 and the partial edge cores 1813a to 1813d.

[0184] As shown in Fig. 19, the bridge cores 1820a and 1820b are arranged on both sides in the x-axis direction with a gap between them. Fig. 19 also illustrates a case in which the bridge cores 1820a and 1820b are arranged to overlap a portion of the main core 1811 when viewed from the z-axis direction. Fig. 19 also illustrates a case in which the bridge cores 1820a and 1820b are arranged to overlap at least a portion of each of the partial edge cores 1812a to 1812d and 1813a to 1813d when viewed from the z-axis direction.

[0185] Here, an example of the arrangement of the bridge cores 1820a and 1820b in this embodiment will be described in more detail with reference to Fig. 19. The end face (lower face) of the bridge core 1820a on the intended transfer surface CP side is in contact with a part of the end face (upper face) on the rear side of the main core 1811, the entire end faces (upper faces) on the rear side of the partial edge cores 1812a to 1812d, and the entire end faces (upper faces) on the rear side of the cooling tubes 1870a to 1870d. The end face (lower face) of the bridge core 1820b on the intended transfer surface CP side is in contact with a part of the end face (upper face) on the rear side of the main core 1811, the entire end faces (upper faces) on the rear side of the partial edge cores 1813a to 1813d, and the entire end faces (upper faces) on the rear side of the cooling tubes 1870e to 1870h.

[0186] However, as long as the bridge cores 1820a and 1820b can be magnetically coupled to the main core 1811 and the edge cores 1812 and 1813, it is not necessary to bring the bridge cores 1820a and 1820b into contact with the main core 1811 and the edge cores 1812 and 1813. For example, the bridge cores 1820a and 1820b may be arranged with a gap between them and the main core 1811 and the edge cores 1812 and 1813. 18 20a, 18 20b is the main core 18 11 and Edge Core 18 12. 18 13. Alternatively, the sensor 14 may be in contact with only one of the sensors 13 or may be opposed to the sensor 13 with a gap therebetween. As described above, this embodiment illustrates a case in which each of the main core 1811 and the edge cores 1812 and 1813 can be magnetically coupled to at least one of the bridge cores 1820a and 1820b.

[0187] The size of the planes parallel to the xy plane of the bridge cores 220a and 220b in the first embodiment is determined according to the size of the planes parallel to the xy plane of the original core 210 and the cooling tubes 270a to 270h. In contrast, the size of the planes parallel to the xy plane of the bridge cores 1820a and 1820b in this embodiment is determined according to the size of the planes parallel to the xy plane of the original core 1810 and the cooling tubes 1870a to 1870h. This is what makes the bridge cores 220a and 220b in the first embodiment different from the bridge cores 1820a and 1820b in this embodiment.

[0188] Therefore, by replacing the symbols given to the original core, bridge core, main core, partial edge core, cooling fins, cooling tubes, coils, and shield plates in the first embodiment with the symbols given in this embodiment and reinterpreting the explanation of the first embodiment, the following scopes can be defined.

[0189] Range of the lap length L on the plate center side of the bridge cores 1820a and 1820b (L≧β) The range of the lap length L' on the plate end side of the bridge cores 1820a and 1820b (L'>0, etc.) Range of height H of bridge cores 1820a and 1820b (H=0.5×h, H=0.5×α, etc.) The range of the ratio of the length BL in the y-axis direction of the bridge cores 1820a and 1820b to the length CL in the y-axis direction of the main core 1811 and the partial edge cores 1812a to 1812d and 1813a to 1813d (BL / CL≧0.2, etc.) )

[0190] Like the upper inductor 1800, the lower inductor 1900 also includes an original core 1910 having a main core 1911 and edge cores 1912, 1913 (partial edge cores 1912a-1912d, 1913a-1913d), bridge cores 1920a, 1920b, a coil 1930, shield plates 1940a, 1940b, cooling fins 1960a-1960h, and cooling tubes 1970a-1970h, and has the same configuration as the upper inductor 1800.

[0191] As described above, in this embodiment, the original cores 1810 and 1910 are so-called T-shaped cores. If the original cores 210 and 310 are E-shaped cores, there is a risk that magnetic flux lines connecting the tip surfaces (magnetic pole surfaces) of two of the three legs (center leg, upstream leg, and downstream leg) of the original cores 210 and 310 may be generated. Therefore, when the original cores 1810 and 1910 are so-called T-shaped cores, the amount of magnetic flux intersecting the strip steel plate 100 in the z-axis direction can be increased more than when the original cores 210 and 310 are so-called E-shaped cores. Therefore, when the original cores 1810 and 1910 are so-called T-shaped cores, the heating efficiency of the strip steel plate 100 can be increased more than when the original cores 210 and 310 are so-called E-shaped cores.

[0192] On the other hand, if original cores 1810, 1910 are so-called T-shaped cores, the eddy currents generated in shield plates 1840a, 1840b increase with an increase in the amount of magnetic flux intersecting steel strip 100 in the z-axis direction. As a result, the magnetic flux generated in upper inductor 1800 and lower inductor 1900 is more likely to be repelled by the eddy currents generated in shield plates 1840a, 1840b, and is more likely to diffuse to the surroundings as noise.

[0193] For the above reasons, for example, when the heating efficiency of the strip steel sheet 100 is prioritized over noise reduction, the induction heating device of this embodiment should be adopted. On the other hand, for example, when the noise reduction is prioritized over the heating efficiency of the strip steel sheet 100, the induction heating device of the first embodiment should be adopted.

[0194] <Modification> In this embodiment, the original cores 1810 and 1910 are so-called T-shaped cores. However, if the distance between the tip surface of the central leg of the original core and the planned transport surface CP is shorter than the distance between the area of ​​the original core other than the central leg and the planned transport surface CP, the original core does not have to be a so-called T-shaped core. For example, the main core and the partial edge core may have the upstream leg and downstream leg described in the first embodiment in addition to the central leg. In this case, it is preferable that the distance between the tip surface of the central leg and the planned transport surface CP is shorter than the distance between the tip surface of the upstream leg and the planned transport surface CP and the distance between the tip surface of the downstream leg and the planned transport surface CP. In this case, the shape of the surface parallel to the yz plane of the original core (main core and edge core) is an E shape in which the length of the middle horizontal line is longer than the two horizontal lines above and below. In addition, the shape of the original core is not limited to the shape shown in the first embodiment and this embodiment.

[0195] In addition to the modified examples described in this embodiment, the various modified examples described in the first embodiment may be adopted in the induction heating device of this embodiment. Also, as in the second embodiment, the original cores 1810, 1910 (main cores 1811, 1911 and edge cores 1812, 1813, 1912, 1913) and the bridge cores 1820a, 1820b, 1920a, 1920b may be configured as one core. Also, as in the third embodiment, a non-magnetic conductor (e.g., a cooling pipe) configured to be cooled may be disposed on the end faces (upper and lower faces) on the rear side of the bridge cores 1820a, 1820b, 1920a, 1920b. Also, both the second embodiment and the third embodiment may be adopted in the induction heating device of this embodiment. Furthermore, even when any of these is adopted in the induction heating device of this embodiment, the various modified examples described in each embodiment may be adopted. In addition, a modified example that combines at least two of the modified examples described above, including the modified examples described in the first, second, and third embodiments, may be adopted in the induction heating device of this embodiment.

[0196] As described above, the only difference between this embodiment and the first embodiment is the shapes of the original cores 210, 310, 1810, and 1910, so a person skilled in the art can understand how to apply at least one of the second and third embodiments to this embodiment. Therefore, a detailed description of the application of at least one of the second and third embodiments to this embodiment will be omitted.

[0197] Furthermore, when the original cores 210, 310, 1810, 1910 and the bridge cores 220a, 220b, 320a, 320b, 1820a, 1820b, 1920a, 1920b are separate cores as in the first, third and fourth embodiments, the bridge cores 220a, 220b, 320a, 320b, 1820a, 1820b, 1920a, 1920b may be moved in the x-axis direction in accordance with the movement of the shield plates 240a, 240b, 340a, 340b, 1840a, 1840b, 1940a, 1940b in the x-axis direction. The movement of the shield plates 240a, 240b, 340a, 340b, 1840a, 1840b, 1940a, and 1940b in the x-axis direction is performed as described in the first embodiment. For example, when the strip steel plate 100 is meandering and the shield plates 240a, 240b, 340a, 340b, 1840a, 1840b, 1940a, 1940b are moved in the x-axis direction (the direction in which the strip steel plate 100 meanders), the bridge cores 220a, 220b, 320a, 320b, 1820a, 1820b, 1920a, 1920b and the shield plates 240a, 240b, 340a, 340b, 1840a, 1840b, 1940a, 1940b may be moved in the x-axis direction (the direction in which the strip steel plate 100 meanders) by an amount equal to the amount of meandering of the strip steel plate 100.

[0198] It should be noted that the above-described embodiments of the present invention are merely illustrative examples of the implementation of the present invention, and the technical scope of the present invention should not be interpreted as being limited by these. In other words, the present invention can be implemented in various forms without departing from its technical concept or main features. [Industrial Applicability]

[0199] The present invention can be used, for example, to inductively heat a conductive plate.

Claims

1. A pair of coils arranged at least one on each of the front and back sides of the intended transport surface of the conductive plate such that an alternating magnetic field generated by passing alternating currents in the same direction crosses the intended transport surface of the conductive plate; and a core arranged in a set for each of the pair of coils, The set of cores arranged for each coil includes a plurality of partial cores arranged at intervals in the width direction, the width direction is a direction perpendicular to a conveying direction of the conductor plate and a facing direction of the coil, Each of the partial cores has a body portion and a central leg portion, the trunk portion extends in the conveying direction from a region upstream of the coil in the conveying direction to a region downstream of the coil in the conveying direction on a rear side of the coil, The back side is opposite to the side on which the transport surface exists, The central leg portion is a transverse type induction heating device that extends from the body portion in the direction of the intended transport surface so as to pass through a hollow portion of the coil, The set of cores includes at least one bridge core that can be magnetically coupled to at least two of the partial cores, A transverse type induction heating device, characterized in that the bridge core is arranged on the rear side of the partial core.

2. 2. The transverse type induction heating device according to claim 1, wherein each of the partial cores can be magnetically coupled to at least one of the bridge cores.

3. 3. The transverse type induction heating device according to claim 1, wherein all of the partial cores included in the set of cores can be magnetically coupled via the bridge core.

4. Each of the set of cores includes a plurality of the bridge cores; 3. The transverse type induction heating device according to claim 1, wherein the bridge cores are arranged with intervals between each other in the width direction.

5. Each of the set of cores has two of the bridge cores, the two bridge cores are disposed on both sides in the width direction with a gap between them; 5. The transverse type induction heating device according to claim 4, wherein at least a portion of each of the partial cores overlaps one of the bridge cores when viewed from the opposing direction of the coils.

6. 3. The transverse type induction heating device according to claim 1, wherein the number of bridge cores in each of the sets of cores is one.

7. 3. The transverse type induction heating device according to claim 1, wherein in the set of cores, the partial core and the bridge core are separate cores.

8. 3. The transverse type induction heating device according to claim 1, wherein in the set of cores, at least one of the plurality of partial cores and at least one of the bridge cores are an integral core.

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