JP2001351775A - Induction heating coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating coil, capable of suppressing heating value of the core, and having superior durability and high performance. SOLUTION: This induction heating coil is equipped with the core, having an internal cooling plate and an external cooling plate and with winding, and an objective face facing opposite to a material to be heated is set on the core. The coil is characterized, by placing the end face on the side of the material to be heated of the external cooling plate on a position retreated from the objective face, or by forming an inclined face on a laminate on the external cooling plate side, or by placing the end face on the side to be heated of the winding on a position which match with the end face on the side to be heated of the external cooling plate on the retreated position, or at a position further retreated from the agreeing position, or by forming the inclined face by laminating steel plates forming the inclined face in the laminating direction of other steel plates forming the core and in the orthogonally intersecting direction with the object face, or by applying a formation obtained by combining these means properly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating coil provided with cooling plates at both ends outside in the laminating direction, for example, an induction heating coil for flat heating with an iron core. Core having an internal cooling plate and external cooling plates disposed at both ends in the stacking direction, and a winding wound around the core and to which an alternating current is applied. The present invention relates to an induction heating coil which is constituted by the end faces of the steel plate and the internal and external cooling plates on the side of the object to be heated, and in which an object plane opposed to the object to be heated is set in parallel.

[0002]

2. Description of the Related Art As a conventional induction heating coil of this type, for example, those described in Japanese Patent Publication No. Sho 62-29875 and Japanese Patent Laid-Open Publication No. Hei 5-299168 are known.

First, as a first conventional example, Japanese Patent Publication No. Sho 62-29
FIG. 6 shows the configuration of the induction heating coil described in
It will be described based on. FIG. 6 is a cross-sectional view of the induction heating coil of the first conventional example. In FIG. 6, reference numeral 1 denotes a silicon steel plate as a steel plate laminated to form the iron core 2. 3A,
Reference numeral 3E denotes a water-cooled copper plate as a cooling plate also constituting the iron core 2, which is located at both ends of the laminated steel plate 1 and sandwiched from both outer sides (hereinafter, these are referred to as external cooling plates). 3B, 3C, and 3D are water-cooled copper plates as cooling plates that also constitute the iron core 2, and are sandwiched between the laminated steel plates 1 at equal intervals (hereinafter, these will be referred to as inner portions). Cooling plate). Note that the above-mentioned external cooling plate and internal cooling plate are also simply referred to as cooling plates.

Reference numeral 4 denotes an insulating fastening bolt for fastening the laminated steel plate 1 and cooling plates 3A to 3E in the laminating direction.
A winding 5 is wound around the iron core 2 composed of the steel plate 1 and the cooling plates 3A to 3E, and an alternating current is applied.
The induction heating coil of Conventional Example 1 configured as described above is
A plane parallel to the surface (plane) of the object 6 to be heated, that is, an object plane, is set on the iron core 2. The objective surface of the iron core 2 is a surface configured by a set of end faces on the heated side of each of the many steel plates 1 and the cooling plates 3A to 3E that constitute the iron core 2.

Next, referring to FIG. 7, an example of the configuration of the water-cooled copper plates 3A to 3E as the above-mentioned cooling plate will be described. The illustrated water-cooled copper plate has a configuration in which a copper tube 9 having an outlet tube 8 is brazed so as to surround the periphery of the copper plate 7 having a predetermined shape. still,
A water-cooled copper plate as a cooling plate of the induction heating coil according to Conventional Example 2 described below has the same structure.

Next, as a second conventional example, Japanese Patent Application Laid-Open No. 5-299
The induction heating coil described in Japanese Patent Publication No. 168 will be described.
This induction heating coil is an improvement of the induction heating coil of the above-mentioned conventional example 1. Hereinafter, description will be made with reference to FIG. FIG. 8 is a cross-sectional view of the induction heating coil of the second conventional example. In FIG. 8, reference numerals 1 to 6 in FIG. 8 are the same as those in the above-described conventional example 1 (FIGS. 6 and 7), and thus description thereof will be omitted.

The difference between the configuration of the induction heating coil of the prior art 1 and that of the prior art 2 is as follows. That is, Conventional Example 1
In the above, the object surface of the iron core 2 was set so as to face the surface of the object 6 to be heated entirely in parallel. Therefore, as shown in FIG. 6 which is a vertical section perpendicular to the object plane of the iron core 2, the heating-side end faces of the steel plate 1 and the cooling plates 3 </ b> A to 3 </ b> B constituting the iron core 2 are arranged side by side in a straight line. 6, that is, the object distance g is constant. Hereinafter, the heated end surface of each steel plate is also referred to as an end surface of the steel plate, and the heated end surface of each cooling plate is also referred to as an end surface of the cooling plate.

In Conventional Example 2 as opposed to Conventional Example 1 described above, an external cooling plate at a position opposite to the end side of the object 6 to be heated,
8 differs from FIG. 8 only in that only the end face of the external cooling plate 3A on the left side of FIG. 8 is retracted in the direction away from the object 6 to be heated from the position of the original object plane of the iron core 2. Therefore, FIG. 8 is a vertical cross section perpendicular to the objective surface of the iron core 2.
As shown in the figure, only the end face of the external cooling plate 3A is greatly apart from the original constant objective distance g between the objective surface of the iron core 2 and the surface of the object 6 by the distance h. The object interval of the external cooling plate 3A with respect to the object 6 to be heated is (g + h). Hereinafter, the objective distance (g + h) of the conventional example 2
From the point that the difference of the distance h occurs vertically with respect to the steel plate 1 in contact with the external cooling plate 3A, the drop of the distance h and the form thereof are referred to as vertical steps.

Next, the operation of the first conventional example will be described. When an alternating current is passed through the winding 5 wound around the iron core 2, an alternating magnetic flux is generated in the iron core 2, and the alternating magnetic flux flows into a metal body to be heated as the object to be heated 6. Induction heating.
At this time, since the iron core 2 is formed by laminating a large number of steel plates 1, in this example, silicon steel plates 1, leakage of magnetic flux to the outside is small. The core 2 self-heats due to hysteresis loss and eddy current loss due to the magnetic flux in the B direction shown in FIGS. 6 and 8 and the magnetic flux in the A direction shown in FIG.

When the self-heating amount of the iron core 2 is small, it is not necessary to cool the iron core 2 itself. However, in order to increase the heat generation density of the object 6 to be heated, the magnetic flux density in the iron core 2 is changed to a high magnetic flux density ( 1T (Tesla) to 2T), and in the case of an induction heating coil, the amount of heat generated in the iron core 2 naturally increases, so that the iron core 2 itself must be cooled. Therefore, the cooling plates 3A to 3A shown in FIG.
E is arranged between a large number of steel plates 1 to be laminated and at both ends.

[0011]

In the induction heating coil (FIG. 6) of the prior art 1 described above, the magnetic flux B causes the external cooling plate 3A on the side located opposite to the end of the object 6 to be heated by induction heating. The external cooling plate 3 is likely to be
There is a problem that the life of the copper tube 9 (FIG. 7) of A is shortened or a crack is generated, thereby causing water leakage.

In order to solve the problem of the first conventional example, the induction heating coil of the second conventional example (FIG. 8) is improved by retreating the external cooling plate 3A greatly to provide a vertical step h. Further, the following problem has occurred. That is, when the vertical step h is small, the external cooling plate 3A is induction-heated by the magnetic flux B as in the case of the induction heating coil of the conventional example 1, and the life of the copper tube 9 is shortened or cracks are generated. For example, the initial problem cannot be sufficiently solved.

On the other hand, in order to solve this problem, if the vertical step h is made sufficiently large, the external cooling plate 3A
, A predetermined width near the external cooling plate 3A, which is stacked on the inner side in contact with the external cooling plate 3A, that is, on the inner side in the stacking direction (external cooling plate side laminated body portion 2A described later, FIGS. 1 and 2). (See FIG. 8), the end of the steel plate 1 on the side of the object to be heated (the end of the steel plate), that is, the end 1A of the iron core (FIG. 8) is subjected to induction heating to increase the heat loss and the external cooling. Since the plate 3A is far away from the end of the steel plate 1, the cooling effect on the end 1A of the iron core is greatly reduced, the temperature is easily increased, and the core 3A is broken by thermal fatigue and electromagnetic vibration. or,
The magnetic flux B causes induction heating of the internal cooling plate 3B closest to the external cooling plate 3A, that is, even the internal cooling plate 3B disposed inside the external cooling plate 3A.
As in the case of (1), there is a problem that a crack is generated in the copper tube of the internal cooling plate 3B to cause water leakage. The present invention
An object of the present invention is to provide a high-performance induction heating coil that solves the above problems, suppresses the heat generation of the iron core, and has excellent durability.

[0014]

According to a first aspect of the present invention, there is provided an iron core having an internal cooling plate disposed at appropriate intervals of laminated steel sheets and external cooling plates disposed at both ends in the laminating direction. A winding wound around an iron core, to which an alternating current is applied, wherein the steel core comprises the steel plate,
In the induction heating coil, which is constituted by the end faces of each of the inner and outer cooling plates on the side of the object to be heated and in which an object plane opposed to the object to be heated is set, each of the end faces of the both outer cooling plates on the side of the object to be heated Is a position retracted from the object plane.

According to a second aspect of the present invention, there is provided an iron core having an internal cooling plate disposed at appropriate intervals of steel sheets to be laminated and external cooling plates disposed at both ends in the laminating direction, and wound around the iron core. And a winding to which an alternating current is applied, wherein the iron core is constituted by the steel plate constituting the iron core, each end face of the object to be heated of the internal and external cooling plates, and is parallel to the object to be heated. In the induction heating coil in which the opposed object surface is set, the object-side end surface of the external cooling plate located on the end side of the object to be heated is set to a position retracted from the object surface, and The heated-side end face of the wire is a position that is advanced from a position that coincides with or coincides with the heated-side end face of the external cooling plate at the retracted position.

According to a third aspect of the present invention, there is provided an iron core having an internal cooling plate disposed at appropriate intervals of laminated steel sheets and external cooling plates disposed at both ends in the laminating direction, and wound around the iron core. And a winding to which an alternating current is applied, wherein the iron core is constituted by the steel plate constituting the iron core, each end face of the object to be heated of the internal and external cooling plates, and is parallel to the object to be heated. In the induction heating coil in which the opposed object planes are set, the heated object-side end faces of the external cooling plates are set at positions retreated from the object plane, and the heated-side end faces of the windings are set back. The position is a position advanced to a position that coincides with or coincides with the heated side end face of the external cooling plate at the set position.

According to a fourth aspect of the present invention, there is provided the first to third aspects.
In the induction heating coil according to any one of the above, the object surface side of the steel sheets stacked within a certain width in the stacking direction from the external cooling plate whose heated side end face is retracted is arranged from the inside in the stacking direction to the outside. The heated-side end face of each steel plate is gradually receded from the object plane, and is an inclined surface that continues to the heated object-side end face of the retracted external cooling plate.

According to a fifth aspect of the present invention, in the induction heating coil according to the fourth aspect, an internal cooling plate is provided on the inclined surface side of the objective surface.

The invention according to claim 6 is the invention according to claims 1 to 3
In the induction heating coil according to any one of the above, the steel plate in the external cooling plate side laminated body portion of the external cooling plate side in which the heated side end face is retracted, in the laminating direction and the object plane of the other steel plates constituting the iron core. While laminating in the direction orthogonal to the
On the object plane side of the steel sheet, the heated object side end face of each steel sheet is formed so as to be continuous with the recessed external cooling plate side heated object end face to form an inclined surface.

The invention according to claim 7 is the invention according to claims 4 to 6.
In the induction heating coil according to any one of the above, the inclined surface has a linear cross section.

The invention according to claim 8 is the invention according to claims 4 to 6.
In the induction heating coil according to any one of the above, the inclined surface has a stepped cross section.

The ninth aspect of the present invention is the fourth aspect of the present invention.
In the induction heating coil according to any one of the above, the inclined surface has a curved cross section.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The induction heating coil according to the first embodiment is installed between a rough rolling mill and a finishing rolling mill in a steel rolling line, and a continuously flowing heated object is rolled and conveyed to a next step by a table roller. It is used for compensating for the temperature of the object to be heated during the heating, and is configured as follows.

That is, the internal cooling plates 3B to 3D as cooling plates disposed at appropriate intervals of the steel plates 1 to be laminated and the external cooling plates 3A and 3E as cooling plates disposed at both ends in the laminating direction are also provided. And a winding 5 wound around the iron core 2 to which an alternating current is applied. The steel core 1 and the cooling plates 3A to 3E constituting the iron core 2 are provided on the iron core 2. Are constituted by the respective heated object side end faces,
An object plane facing the object to be heated 6 is set in parallel.

Hereinafter, Embodiment 1 will be described with reference to FIG. FIG. 1 is a vertical section perpendicular to the object plane. Note that the same reference numerals and terms as those described in Conventional Example 1 and Conventional Example 2 are the same or substantially the same, and a description thereof will be omitted.

In FIG. 1, reference numeral 1 denotes a silicon steel plate as a steel plate, and 2 denotes an iron core.
A to 3E are stacked. Reference numerals 3A and 3E denote water-cooled copper plates as external cooling plates, which are arranged outside both ends of the iron core 2 in the laminating direction. Reference numerals 3B, 3C, and 3D denote water-cooled copper plates serving as internal cooling plates, which are interposed at appropriate positions in the laminating direction of a large number of steel plates 1 constituting the iron core 2, and are disposed therebetween. Reference numeral 4 denotes an insulating fastening bolt, which fastens a large number of laminated steel plates 1 and cooling plates 3A to 3E in a laminating direction. Reference numeral 5 denotes a winding, which is wound around the iron core 2, that is, a laminate including the steel plate 1 and the cooling plates 3A to 3E, to which an alternating current is applied. 6 is a flat steel plate as an object to be heated.

In FIG. 1, a winding 5 wound around an iron core 2
When an alternating current is supplied to the iron core 2, an alternating magnetic flux is generated in the iron core 2, and the alternating magnetic flux flows into the metal body to be heated, that is, the above-described heated object 6, and the heated object is induction-heated.

In the first embodiment, the end faces (the end faces of the external cooling plates) of the two water-cooled copper plates 3A and 3E as the external cooling plates disposed on both ends in the stacking direction of the iron core 2 on the side of each object to be heated. To be heated 6 by the distance h from the object plane of the iron core 2
So that it is in a position retracted away from
Each of the iron cores 2 located on both ends in the stacking direction of the iron core 2 such that the distance between the iron core 2 and the surface of the object 6 becomes g + h (g is the distance between the object surface of the iron core 2 and the surface of the object 6). External cooling plate 3A,
3E is provided.

Next, from the steel plate 1 in contact with each of the two external cooling plates 3A and 3E disposed at the retracted position as described above, the steel plate 2 having a certain width laminated inward in the laminating direction.
A (hereinafter, also referred to as an external cooling plate side laminated body portion), the core 2
From the inner steel plate 1 to the outer steel plate 1, the heated core end surfaces (the end surfaces of the steel plates) of the steel plates 1 are arranged so as to gradually recede from the objective surface, and the iron core left on the center side in the laminating direction. 2 are formed so as to be inclined surfaces connected to the heated object side end surfaces (end surfaces of the external cooling plates) of the respective external cooling plates 3A and 3E disposed at the retracted positions from the original objective surfaces. Have been.

Here, the above-mentioned inclined surface is generally summarized by a set of a large number of end surfaces such as the end surfaces of the steel plates 1 and, in some cases, the end surfaces (not shown) of the cold water plates interposed between these steel plates 1. Obliquely formed surface, for example, refers to a surface whose cross section is linear, stepped or curved, and the obliquely surface is not necessarily a smooth surface, for example, each end surface May be parallel to the object plane or the plane of the object 6 to be heated. As described above, the inclined surface shown in the first embodiment is the object surface left on the center side of the iron core 2 from the extending direction of each end surface of the external cooling plates 3A and 3E on both sides, and the object 6 to be heated in the drawing. The area up to contact with the object plane parallel to the plane is defined as an inclined area.

The inclined surfaces provided on the heated object side at both ends in the stacking direction of the iron core 2, that is, on the outer cooling plate side laminated body portion 2A, extend beyond the retreated outer cooling plates 3A, 3E.
The magnetic flux B is formed so as to be able to effectively prevent the magnetic flux B from flowing into the steel plate 1 and the internal cooling plates 3 </ b> B and 3 </ b> D on the inside thereof. Therefore, the "within the fixed width" (the steel plate 2A) refers to a region where the magnetic flux B easily flows (the outer cooling plate side laminated body portion).

In the first embodiment, the external cooling plate 3A,
3B and an inner cooling plate 3B located on the inner side of each of them,
3D, a region where the magnetic flux B easily flows, that is, within a certain width, and the external cooling plate side laminated body portion 2 laminated within this width.
A number of steel sheets 1 constituting A are set as a set of several sheets, and the set is used as a unit, for example, an end face of each steel sheet 1 of a set of three sheets is formed as a series of faces, one of which is low on both sides of this face, The other steel sheet 1 for each set of three sheets is sequentially arranged with a step so as to have a high step shape, thereby forming a step-like inclined surface.

According to the first embodiment, the calorific value of the iron core 2 can be greatly reduced. The reason is as follows. First, in Conventional Examples 1 and 2 described above,
At both ends in the stacking direction of the iron core 2 on the object plane side, that is, the conventional example 2
The heat generation at the core end 1A (FIG. 8) is caused by the end face of the external cooling plate and the number of steel sheets laminated inside the end face, that is, the end face of each of the external cooling plate side laminated body portions 2A on the side of each object to be heated. It was found that the level difference (h) was one of the factors.

That is, the magnetic flux penetrating through the iron core 2 and the amount of heat generated at the iron core end 1A (FIG. 8) were examined by variously changing the step height h. It was found that the calorific value was proportional to the square of the area of the portion of the steel sheet 1 protruding from the external cooling plate, and was inversely proportional to the square of the circumference thereof. That is, when the lengths in the stacking direction are the same, it is proportional to the square of the step amount h. Similar results were obtained for the step between the steel plates 1.

For such a reason, the heat generation amount of the iron core 2 can be largely suppressed by configuring as in the first embodiment. In the first embodiment,
In this embodiment, both outer cooling plates 3A and 3B are retracted at both ends in the laminating direction of the iron core 2 and the inclined surfaces are provided on each of the outer cooling plates 3A and 3B. The external cooling plate may be retreated only on the side of the external cooling plate located at the position described above, or the inclined surface as described above may be provided.
Also, depending on the inflow of the magnetic flux B, the inflow of the magnetic flux B can be sufficiently prevented only by adopting a configuration in which the inclined surfaces are not provided and the external cooling plates 3A and 3B are retracted.

Embodiment 2 The induction heating coil according to the second embodiment is basically substantially the same as the induction heating coil according to the first embodiment. Hereinafter, description will be given based on FIG. FIG. 2 is a vertical section perpendicular to the object plane. Note that the same reference numerals or terms as those in the first embodiment have the same or substantially the same contents, and a description thereof will not be repeated.

As shown in FIG. 2, this induction heating coil is also provided with internal cooling plates 3B to 3D sandwiched at appropriate intervals of the laminated steel plates 1 and external cooling plates 3A, 3E disposed at both ends in the laminating direction. And a winding 5 wound around the iron core 2 to which an alternating current is applied. The steel plate 1 and the cooling plate constituting the iron core 2 are provided on the iron core 2. An object plane which is constituted by the heated object side end faces 3A to 3E and faces in parallel with the heated object 6 is set. These configurations are the same as in the first embodiment.

In the second embodiment, the windings 5 are connected to the end surfaces of the external cooling plates 3A and 3E on the side of the object to be heated (the end surfaces of the external cooling plates 3A and 3E). The configuration is such that a side end face (hereinafter, also referred to as an end face of the winding 5) is arranged at a position where it coincides or is retracted further away from the object to be heated 6 from a position where it coincides. Hereinafter, description will be made with reference to FIGS. 4 and 5. FIG. 4 shows the heat generation ratio of the water-cooled copper plate 3A as the external cooling plate and the protrusion amount h of the (end surface) of the water-cooled copper plate 3A as the external cooling plate from the end surface of the winding 5.
FIG.

As shown in FIG. 4, the external cooling plates 3A, 3E
, The calorific value ratio decreases. However, the steel plate 1 in contact with the external cooling plates 3A, 3E and inside the iron core 2, that is, a steel plate having a certain width laminated in the laminating direction, that is, the end of the external cooling plate side laminated body portion 2A (FIG. 2) on the heated object side. From the viewpoint of the cooling effect on the heat on the (end of the steel plate) side and the mechanical strength, the optimum value of the protrusion amount h must be appropriately selected. In this example, k = 0 to -5 mm.

This is because it was found that the amount of heat generated in the external cooling plates 3A and 3E was in the positional relationship between the end surface of the winding 5 and the end surface of the external cooling plate 3, and for example, When the external cooling plate 3A was moved to various positions in the direction of the object 6 to be heated and the amount of heat generated by the external cooling plate 3A was examined, the position of the end surface of the external cooling plate 3A was changed from the position of the end surface of the winding 5 to the position of the heating surface. It was found that the amount of heat generated by the external cold plate 3 </ b> A sharply increased as it protruded toward the heating object 6. Less than,
The end face of the winding 5 is also called a winding end face. FIG. 4 shows the result of measuring the relationship between the calorific value of the water-cooled copper plate and the amount of protrusion k of the water-cooled copper plate from the winding end surface.

As shown in FIG. 5, the distance between the objective surface of the iron core 2 and the end surface of the winding 5 is set at a distance j = 10 mm.
When the amount of protrusion k of the end face of the external cooling plate 3A from the end face of the winding 5 was changed and the calorific value of the external cooling plate 3A was measured, as shown in FIG. In this case, when k = −10 mm, it is about 0.8 times, and when k = 10 mm, it becomes about 1.7 times, so that the end face of the external cooling plate 3 </ b> A The outer cooling plate 3 </ b> A
The calorific value of this increased sharply.

Therefore, as in the second embodiment, the winding 5 is made to coincide with the end faces of the external cooling plates 3A and 3E, or the heating object is further moved from a position coincident with the end faces of the windings 5. 6, the amount of heat generated at the relevant portions of the external cooling plates 3A and 3E can be significantly reduced.
Further, by combining the various embodiments described in the first embodiment with the configuration of the second embodiment, the amount of heat generated by the iron core 2 and the cooling plate as a whole can be further suppressed. Further, it is possible to provide an induction heating coil having good performance in accordance with the amount of the magnetic flux B flowing.

Although the first embodiment does not describe the characteristic features of the above-described configuration in the second embodiment, as shown in FIG. The configuration is provided with the above-described features. Therefore, also in the first embodiment, by combining the features of the above-described features of the second embodiment, not only the same operation and effect as in the second embodiment but also a synergistic effect can be used to effectively generate heat from the iron core 2. The amount can be suppressed.

Embodiment 3 FIG. The third embodiment is different from the first and second embodiments in that the outer cooling plate side laminated body portion (2) of the outer cooling plate whose heated side end face is retracted.
This is an improvement of the lamination direction of the steel sheet in A). That is, the steel plate in the external cooling plate side laminated body portion of the external cooling plate side in which the heated side end face is receded is laminated in a direction perpendicular to the laminating direction of the other steel plates constituting the iron core and the object plane, Further, the heated object side end face of each steel sheet is inclined to the object plane side of the steel sheet of the external cooling plate side laminated body portion thus laminated so as to be continuous with the heated object end face of the retracted external cooling plate side. It has a configuration in which a slanted surface is provided by being formed in an inclined shape.

Hereinafter, description will be made with reference to FIG. FIG.
FIG. 4 is a perspective view showing a state in which an object surface of an iron core 2 faces a lower surface side of an object to be heated. In FIG. 3, reference numerals 3A and 3E denote retreated outer cooling plates, and a steel plate 1 having a certain width laminated inward from the steel plate 1 in contact with the external cooling plates 3A and 3E, that is, in FIGS. The steel plates 1 constituting the external cooling plate side laminated body portion 2 </ b> A shown are laminated in a direction perpendicular to the laminating direction of the other steel plates 1 and the object plane of the iron core 2.

The heated object side end face of each of the steel plates 1 constituting the outer cooling plate side laminated body portion 2A stacked in the orthogonal direction is separated from the object plane of the iron core 2 by the retracted outer cooling plate. 3A and 3E so as to continue to the heated object side end faces,
One shoulder in the width direction of the steel plate 1 is deleted to provide an inclined surface on the object-to-be-heated end surface. An inclined surface is provided.

As for the aspect of the inclined surface of the third embodiment, similarly to the inclined state described in the first embodiment, the cross section may be formed in a stepped or curved shape. In this case, in the third embodiment, since the width direction of many stacked steel plates 1 forming the inclined surface is directed to the stacking direction of the other steel plates 1 forming the iron core 2, For example, for example, the corner portion on one side in the width direction of each steel plate 1 constituting the inclined surface can be easily formed into a desired line such as a linear shape, a step shape, or a curved curved shape. Then, by simply laminating the required number of laminated steel sheets 1 of the same shape thus formed, the inclined surface can be provided relatively easily.

Further, by using a silicon steel plate as the steel plate 1 constituting the inclined surface according to the third embodiment, the heat conductivity of the outer cooling plate side laminated body portion 2A having the inclined surface is 5%. It can be improved about twice. This is because the fact that the thermal conductivity of the silicon steel sheet is about 5 times better in the creeping direction than in the vertical direction is used. Therefore, heat conduction to the external cooling plates 3A and 3B is significantly increased, and the cooling effect of the relevant portion of the iron core 2 and its peripheral portion can be remarkably improved.

As shown in FIG. 3, the inclined surface of the third embodiment is provided on the outer cooling plate side laminated body portion 2A on both sides of the iron core 2, but faces the end of the object 6 to be heated. The external cooling plate side laminated body portion 2A may be provided only on the position of the external cooling plate 3A (see FIGS. 1 and 2) on the position side. Further, in the first and second embodiments, by combining the configuration shown in the third embodiment, not only the same operation and effect as in the third embodiment, but also the synergistic effect, Can be effectively suppressed.

[0050]

According to the first to ninth aspects of the present invention,
In any case, the heat generation amount of the iron core can be reduced as compared with the related art, and a high-performance induction heating coil with high durability and stable operation can be provided.

According to the second aspect of the present invention, it is possible to efficiently suppress heat generation at the end of the iron core facing the end face of the object to be heated.

According to the third aspect of the present invention, the durability of the external cooling plates on both sides of the iron core can be improved, and the inflow of magnetic flux into the external cooling plate side laminated body can be efficiently prevented. Heat generation of the iron core can be suppressed efficiently.

According to the fifth aspect of the present invention, the heat generation at the outer cooling plate side laminated body portion of the iron core can be efficiently suppressed in cooperation with the outer cooling plate.

According to the sixth aspect of the present invention, the cooling efficiency of the external cooling plate of the iron core can be remarkably increased, and the heat generation of the external cooling plate side laminated body portion of the iron core can be largely suppressed. Therefore, the life of the internal cooling plate and the steel plate can be greatly extended.

[Brief description of the drawings]

FIG. 1 is a longitudinal section of an induction heating coil according to a first embodiment.

FIG. 2 is a longitudinal section of an induction heating coil according to a second embodiment.

FIG. 3 is a perspective view showing a state where an induction heating coil according to a third embodiment is directed to a lower surface side of an object to be heated;

FIG. 4 is a diagram illustrating a relationship between a heat generation ratio of an external cooling plate and a protrusion amount k from a winding end surface.

FIG. 5 is an explanatory diagram showing the amount of protrusion of a steel plate and an external cooling plate constituting a core from windings.

FIG. 6 is a cross-sectional view of an induction heating coil according to Conventional Example 1.

FIG. 7 is a plan view of a water-cooled copper plate.

FIG. 8 is a cross-sectional view of an induction heating coil according to Conventional Example 2.

FIG. 9 is a side view of the iron core of Conventional Example 2 viewed from both directions.

[Explanation of symbols]

Reference Signs List 1 silicon steel plate (steel plate), 2 iron core, 2A external cooling plate side laminated body portion, 3A, 3E external water-cooled copper plate (external cooling plate), 3B, 3C, 3D internal water-cooled copper plate (internal cooling plate), 5 windings, 6 Object to be heated, g object distance (distance between the surface of the object to be heated and the object surface of the iron core), h distance between the object surface of the iron core and the end surface of the external cooling plate), j the end surface of the winding and the object surface of the iron core , K Distance between the end face of the winding and the end face of the external cooling plate.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K059 AA10 AB19 AB26 AB28 AC10 AC54 AD07 AD15 AD28 AD34 CD44 CD48 CD52 CD53 CD73 CD77

Claims (9)

[Claims] 1. An iron core having internal cooling plates disposed at appropriate intervals of steel sheets to be laminated and external cooling plates disposed at both ends in the laminating direction, and an alternating current is wound around the iron core and applied thereto. The steel core constituting the iron core, an object surface formed by each end face of the inner and outer cooling plates on the side of the object to be heated, and opposed to the object to be heated in parallel. In the induction heating coil, an end surface of each of the external cooling plates on the side of the object to be heated is set at a position retracted from the objective surface. 2. An iron core having internal cooling plates disposed at appropriate intervals of steel sheets to be laminated and external cooling plates disposed at both ends in the laminating direction, and an alternating current is wound around the iron core and applied thereto. The steel core constituting the iron core, an object surface formed by each end face of the inner and outer cooling plates on the side of the object to be heated, and opposed to the object to be heated in parallel. In the induction heating coil in which is set, the heated object side end face of the external cooling plate located on the end side of the heated object is a position retracted from the objective surface, and the heated side of the winding. An induction heating coil, wherein the end surface is a position that is advanced from a position that coincides with or coincides with the heated end surface of the external cooling plate at the retracted position. 3. An iron core having an internal cooling plate and an external cooling plate disposed at both ends in the laminating direction of a steel sheet to be laminated, and an alternating current wound around the iron core. The steel core constituting the iron core, an object surface formed by each end face of the inner and outer cooling plates on the side of the object to be heated, and opposed to the object to be heated in parallel. In the induction heating coil, the heated object side end faces of the two external cooling plates are set at positions retreated from the object plane, and the heated side end faces of the windings are set at the retreated position. An induction heating coil, wherein the induction heating coil is located at a position which coincides with or is advanced from a position which coincides with or coincides with a heated end surface of the external cooling plate. 4. The object side of the steel sheet laminated within a certain width in the laminating direction from the external cooling plate whose heated side end face is receded is the heated side of each steel sheet arranged from the inner side to the outer side in the laminating direction. The end surface is gradually receded from the objective surface, and is an inclined surface that continues to the heated object-side end surface of the retracted external cooling plate. Induction heating coil as described. 5. The induction heating coil according to claim 4, wherein an internal cooling plate is disposed on the inclined surface side of the objective surface. 6. The steel sheet in the outer cooling plate side laminated body portion on the outer cooling plate side in which the heated side end face is retreated is moved in the direction perpendicular to the laminating direction of the other steel sheets constituting the iron core and the object plane. Along with lamination, on the object surface side of the steel plate, the heated object side end surface of each steel plate is formed so as to be continuous with the heated object end surface on the retreated outer cooling plate side, thereby forming an inclined surface. The induction heating coil according to any one of claims 1 to 3, wherein 7. The induction heating coil according to claim 4, wherein the inclined surface has a linear cross section. 8. The induction heating coil according to claim 4, wherein the inclined surface has a stepped cross section. 9. The induction heating coil according to claim 4, wherein the inclined surface has a curved cross section.