JP2587156B2 - Induction heating coil - Google Patents

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 for heating a flat surface with an iron core.

[0002]

2. Description of the Related Art As a conventional induction heating coil of this type, for example, a coil described in Japanese Patent Publication No. Sho 62-29875 is known. The induction heating coil and the water-cooled copper plate described in this publication will be described with reference to FIGS.
In each figure, 1 is a silicon steel plate having a convex leg, 2 is an iron core having a convex leg formed by stacking silicon steel plates 1, 3A,
3D has two water-cooled copper plates sandwiching the iron core 2 from both sides, 3B,
3C is a 2C sandwiched in the stacking direction of the silicon steel plate 1 of the iron core 2.
4 water-cooled copper plates, 4 is a silicon steel plate 1 and water-cooled copper plates 3A to 3D
Are wound around the iron core 1 and the convex legs of the water-cooled copper plates 3A to 3D to apply an alternating current, and 6 is an object to be heated.

Next, the operation will be described. When an alternating current is applied to the winding 5 wound around the convex leg of 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 object 6 to be heated. The heating object 6 is induction-heated. At this time, since the iron core 2 is formed by stacking the convex silicon steel plates 1, leakage of magnetic flux to the outside is reduced, and the iron core 2 has a hysteresis loss and a hysteresis loss due to the magnetic flux in the A direction and the magnetic flux in the B direction. Self-heating occurs due to eddy current loss. When the calorific value is small, it is not necessary to cool the iron core 2, but the heating target 6
In the case of an induction heating coil in which it is necessary to increase the magnetic flux density in the iron core 2 to a high magnetic flux density (10,000 to 20,000 gauss) in order to increase the heat generation density of the iron core 2, the amount of heat generated in the iron core 2 increases, and the iron core 2 is cooled. I have to do it. Conventionally, for example, four water-cooled copper plates 3
A to 3D are used with the same distance g between the silicon steel sheet 1 and the object 6 to be heated, and fastening these with the insulating bolts 4. As shown in FIG. 4, these water-cooled copper plates 3 </ b> A to 3 </ b> D were brazed so as to surround the copper plate 7 with a copper tube 9 having an outlet tube 8.

[0004]

However, since the conventional induction heating coil has the above-described structure, the water-cooled copper plates 3A and 3D at both ends of the iron core 2 are particularly easily heated by the magnetic flux B, and a large heat loss is generated. And another water-cooled copper plate 3
There is a problem that the life of the copper tubes 9 of the water-cooled copper plates 3A and 3D is shorter than those of the tubes B and 3C, and there is a possibility that the copper tubes 9 are cracked to cause a water leakage accident.

An object of the present invention is to provide an induction heating coil capable of reducing the loss of a water-cooled copper plate and extending the life of the water-cooled copper plate of an iron core. It is an object.

[0006]

An induction heating coil according to the present invention is provided with an iron core formed by stacking silicon steel plates having convex legs, a water-cooled copper plate sandwiching the iron core from both sides, and a stacking direction of the silicon steel plates. A plurality of water-cooled copper plates, insulating bolts for fastening them in the laminating direction, and a winding wound around the iron core fastened by the insulating bolts and the convex legs of the cooling copper plate to apply an alternating current. In an induction heating coil for induction heating of a heated object, an interval between the water-cooled copper plate and the object to be heated opposed thereto is set to be larger than an interval between the silicon steel sheet and the object to be heated opposed thereto, and A step is formed between a copper plate and a silicon steel plate.

[0007]

According to the present invention, since the distance between the water-cooled copper plate and the object to be heated is set to be larger than the distance between the silicon steel plate and the water-cooled copper plate and the silicon steel plate are attached with a step, the water-cooled copper plate has a magnetic flux. In addition to being less affected, self-heating is reduced, the loss of the water-cooled copper plate can be reduced, and the life of the water-cooled copper plate at both ends of the iron core can be extended.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, based on the embodiment shown in FIG. FIG. 1 is a side view showing one embodiment of the induction heating coil of the present invention.

As shown in FIG. 1, an induction heating coil according to the present embodiment has an iron core 2 formed by stacking silicon steel plates 1 having convex legs, and two water-cooled copper plates 3 sandwiching the iron core 2 from both sides.
A, 3D and two water-cooled copper plates 3B and 3C sandwiched in the stacking direction of silicon steel plates, insulating bolts 4 for fastening these in the stacking direction, and iron core 2 and water-cooled copper plates 3A to 3D fastened by insulating bolts 4. A winding 5 is provided around the convex leg to apply an alternating current, and is configured to heat the object 6 to be heated.

The induction heating coil according to the present embodiment has a distance (g + g) between the water-cooled copper plate 3A and the object 6 to be heated opposed thereto.
h) is set to be larger by the distance h than the distance g between the silicon steel sheet 1 and the object 6 to be heated facing the silicon steel sheet 1, and the water-cooled copper sheet 3 </ b> A and the silicon steel sheet 1 are provided with steps. Each of the water-cooled copper plates 3A to 3D is brazed so as to surround the copper plate 7 with a copper tube 9 having an outlet tube 8 as in the conventional case.

Next, the operation will be described. Alternating magnetic flux generated by passing an alternating current through the winding 5 wound around the convex leg of the iron core 2 is concentrated on the edge 6A side of the heated object 6 with respect to the central side 6C in the plate width direction by the edge effect. . In particular, the water-cooled copper plate 3A is located farther than the object 6 to be heated by the distance h from the silicon steel plate 1, and is less susceptible to the magnetic flux by the distance.
The self-heating value is reduced, and the loss is reduced. In the end,
The stress of the water-cooled copper plate 3A is also reduced, and its life is prolonged.

The effect of the magnetic flux of the water-cooled copper plate 3A becomes smaller as the step h with respect to the silicon steel plate 1 is larger, but conversely,
Since the temperature of the silicon steel sheet 1, particularly the surface of the silicon steel sheet 1 located between the water-cooled copper sheet 3A and the water-cooled copper sheet 3B, which faces the object 6 to be heated, rises and exceeds the allowable temperature of the silicon steel sheet 1, The step h is naturally limited. Therefore, water-cooled copper plate 3A
The relationship between the loss of steel, the temperature of the silicon steel sheet 1 and the step h was determined by experiment and numerical calculation.
It was found to be 10 mm to 10 mm.

In the above embodiment, the step h between the water-cooled copper plate 3 and the silicon steel plate 1 is attached to the edge 6A of the object 6 to be heated, that is, the water-cooled copper plate 3A on the left side of the iron core 2 in FIG. Although only described, other water-cooled copper plates 3B ~
By providing similar steps in 3D, the same effects as in the above embodiment can be expected. In short, the induction heating coil of the present invention sets the distance between the water-cooled copper sheet and the object to be heated facing the water-cooled copper sheet larger than the distance between the silicon steel sheet and the object to be heated facing the silicon-coated steel sheet. What is necessary is just to add steps.

[0014]

As described above, according to the present invention, it is possible to provide an induction heating coil capable of reducing the loss of the water-cooled copper plate and extending the life of the water-cooled copper plate of the iron core.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of an induction heating coil of the present invention.

FIG. 2 is a front view showing an example of a conventional induction heating coil of the present invention.

FIG. 3 is a side view showing the induction heating coil shown in FIG. 2;

FIG. 4 is a front view showing a water-cooled copper plate of the induction heating coil shown in FIGS. 1 and 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silicon steel plate 2 Iron core 3A Water-cooled copper plate 4 Insulation bolt 5 Winding 6 Heated object

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-169888 (JP, A) JP-A-58-148897 (JP, U) JP-A-59-69499 (JP, U) 29875 (JP, B2)

Claims (1)

(57) [Claims] An iron core formed by stacking silicon steel plates having convex legs, a water-cooled copper plate sandwiching the iron core from both sides, and a plurality of water-cooled copper plates sandwiched in the stacking direction of the silicon steel plate of the iron core;
Insulation bolts for fastening them in the laminating direction, and windings for applying an alternating current wound around the iron core fastened with the insulation bolts and the convex legs of the cooling copper plate, and induction heating the object to be heated. In the heating coil, the distance between the water-cooled copper plate and the object to be heated opposed thereto is set larger than the distance between the silicon steel sheet and the object to be heated opposed thereto,
An induction heating coil, wherein a step is provided between the water-cooled copper plate and the silicon steel plate.