JPS5830703B2 - induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating device for induction heating a continuously transferred steel plate.

FIG. 1a shows a plan view and a side view of a conventional heating device.

A conventional heating device has iron cores 2a and 2b near the object 1 to be heated.
, and energize coils 3a, s3b, 4a, and 4bK,
The polarity of magnetic poles A, B, C, and D was made to be alternate.

In this case, the distance between the magnetic poles is widened to increase heating efficiency, but the larger the opposing area between the magnetic poles, the more leakage magnetic flux that passes through the coil increases, which has the disadvantage that the Joule loss of the coil becomes extremely large. .

In addition, when one convex part of the iron core constitutes one magnetic pole and the magnetic pole spacing is wide as in the conventional case, the density of the electric power entering the heated object 1 changes greatly, and the heat generation distribution on the heated object 1 changes. becomes uneven.

As a result, there are parts where the temperature is increased more than necessary, and parts where the total temperature is not raised, resulting in poor heating efficiency when considering the parts that need to be heated.

This invention has been made in view of these points, and has a coil and iron core structure in which a large number of coils are provided and one magnetic pole is constituted by many convex portions of the iron core, and an induction heating device that does not have the above-mentioned drawbacks. The purpose is to provide

An embodiment of the present invention shown in FIGS. 2 and 3 will be described below.

In FIG. 2, the steel plate 1 is transferred at a speed V, and the iron core 2a is provided with a number of slots, and coils 6a to 6i are provided in the slots as shown in the winding diagram shown in FIG.

These coils are connected and connected to a single-phase AC power source 5, and a current (2) is caused to flow in the direction of the arrow in the figure to generate a magnetic pole on the convex portion of the iron core 2a.

The strength of this magnetic field has a gentle distribution, and the strongest point is at position A shown in the figure.

B and C.

By distributing the current and magnetic poles as described above, it is easy to reduce the opposing area between the poles, suppress magnetic flux leakage between the poles, reduce Joule loss in the coil, and reduce the heat generation distribution on the workpiece. Since it can be done uniformly, it is possible to suppress wasted power due to local overheating, and it is possible to improve heating efficiency.

Furthermore, since the magnetic poles are subdivided, the heating area can be easily selected.

FIG. 4 shows another embodiment of the present invention.

The iron core 2a has a structure in which the area where the magnetic field is strong is wider than the other convex parts in the direction of conveying the steel plate.

This reduces leakage flux through the coil and reduces coil losses.

Further, by arbitrarily selecting the cross-sectional area of the convex portion, the power distribution entering the heated body can be adjusted, and the temperature distribution of the steel plate, which is the heated body, can be arbitrarily designed.

[Brief explanation of drawings]

Fig. 1 shows a conventional induction heating device, where a is a plan view, the same figure is a partially enlarged side view, Fig. 2 is a side view showing an embodiment of the present invention, and Fig. 3 is a side view showing an enlarged part of the device. Its winding diagram is shown. FIG. 4 shows another embodiment of the invention. It is a schematic diagram. In the figure, 1 is an object to be heated, 2a and 2b are iron cores,
51I'i single-phase power supply, 6a to 6i are coil conductors, A-D
is a magnetic pole. Note that the same reference numerals in the drawings indicate the same or equivalent parts.

Claims (1)

[Claims] 1 In an induction heating device in which an iron core additional heating coil is provided facing the surface of a metal plate to be heated that is continuously transferred, a large number of slots are provided in the iron core in a direction perpendicular to the direction of movement of the heated object, and the coils in the The coils are arranged so that the current flowing in the direction is the same across at least two slots, the magnetic poles on the iron core surface alternate in the direction of movement of the plate heating element, and a single-phase AC power source is connected to the coils. Features of induction heating equipment.