JPS6310542B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a crossed magnetic field type induction heater, and particularly to a crossed magnetic field type induction heater which is equipped with an auxiliary heater in addition to a main heater and is suitable for heating non-magnetic thin plate materials. Regarding heaters.

Conventional technology: In addition to the main heater, an auxiliary heater is provided, and if only the main heater is used, the temperature near the ends of the object to be heated is low in the width direction of the object, and uniform heating cannot be obtained. In order to solve this problem, a cross-magnetic field type induction heater is disclosed, for example, in JP-A-60-221986, which uses an auxiliary heater to perform corrective heating on this part to obtain a uniform temperature distribution as a whole.
However, in this device, the main heater has four magnetic poles (N, S,
N, S) is used as one unit, and an auxiliary heater is arranged downstream of the main heater in the direction of movement of the object to be heated, and both are used to heat the object. Most of the power (70-90%) will be supplied to the main heater. Therefore, as a result of being heated intensively by the main heater, the temperature difference between the widthwise center of the object to be heated and near the edges increases in proportion to the heating power, especially when the object to be heated is a thin plate material. The problem is that thermal distortion occurs, causing displacement of the thin plate material in the direction of the gap between the main heaters above and below the thin plate, resulting in deformation due to thermal distortion before it passes through the auxiliary heater, which should be subjected to corrective heating next. There is. In addition, the structure of the auxiliary heater is such that when the excitation coils are housed in slots provided in the iron core parallel to the central axis of the object to be heated and wound, the excitation coils are wound in a rectangular spiral shape parallel to the surface of the object to be heated. Therefore, the structure is complicated, and the coil winding work is also complicated.

Problems to be Solved by the Invention An object of the present invention is to provide a cross-magnetic field type induction heater that does not cause large thermal distortion to a heated object due to rapid concentrated heating of the main heater.

Measures to solve the problem The main heater, which had a conventional four-magnetic pole configuration as one unit, was divided into two parts, with N-pole and S-pole magnetic poles and excitation coils related to these, with the object to be heated sandwiched between them. A plurality of pairs of main heaters arranged one above the other are arranged alternately with at least one pair of auxiliary heaters along the moving direction of the object to be heated.

Function Each pair of main heaters distributed along the moving direction of the object to be heated with the pair of auxiliary heaters in between heats the object to be heated in multiple stages, and
Heating by the main heater and auxiliary heating by the auxiliary heater are performed alternately.

Embodiment FIG. 1 is a side view of an embodiment of the cross-field induction heater of the present invention, showing two main heater pairs 1a and 1b and an auxiliary heater pair 2 disposed between them. and each pair of main heaters 1a and 1b
In this case, two main heaters 10 and 11 having the same structure are arranged in a pair above and below an object to be heated, for example, a plate 3. Similarly, the auxiliary heater pair 2 is made up of a pair of upper and lower auxiliary heaters 20 and 21 having the same structure. The structure of the main heaters 10 and 11 is the same as that of the conventional main heater described above, except that each is composed of two magnetic poles (N and S), and an exciting coil 13 and an excitation coil 13 are attached to each magnetic pole. 14 is wound, and an alternating magnetic field is generated from each magnetic pole by an applied alternating current.

The structure of the auxiliary heaters 20 and 21 differs from that of the auxiliary heater used in the above-mentioned conventional cross-magnetic field type induction heater in the way in which the exciting coils housed in each slot are wound around the iron core. Figure 2 A, B and C
2 shows a plan view, a side view, and a sectional view of pair 2 of auxiliary heaters. A slot is formed at a position on the iron core 22 of the auxiliary heater so as to cover the insufficient heating by the main heater near the widthwise end of the plate material 3 (two locations symmetrical with respect to the central axis X of the plate material 3). On the 24th,
An excitation coil 23 is housed in each, and after extending along the slot 24, the excitation coil 23 is wound around the iron core 22 along the back surface of the iron core 22 in the form of a body wrap. Therefore, the excitation coil in each slot does not contact, overlap or intersect with other excitation coils laterally or above and below, and is separated and independent for each slot, making the winding work easy. The structure is also simple. In addition, unlike conventional rectangular spiral coils, the coil portion that crosses the plate material 3 in the width direction W from the slot on one side of the plate material 3 in the width direction W to the slot on the other side is unnecessary, and the structure is simple. is also saved. The excitation coils wound around each slot are each provided with an external terminal 25 and connected to a respective power source. As these power sources, those similar to those used in the above-mentioned conventional crossed magnetic field type induction heater can be used.

To explain the operation, as shown in Fig. 1, the plate material 3
When moving in the direction of the arrow, the plate 3 is first heated by the main heater pair 1a, but since it has a two magnetic pole (2 magnetic pole) configuration compared to the conventional four magnetic pole configuration, the main heating The time for passing through the container, that is, the heating time, is also about half, and at this stage, the temperature has not yet risen to the predetermined final temperature. Next, the plate material 3 passes through the pair of auxiliary heaters 2, so that the main heater performs corrective heating of the portions that are not sufficiently heated. Board material 3 is
It then passes through the main heater pair 1b where it is heated to a predetermined final temperature. Therefore, in the past, while the plate material passed through a pair of main heaters (four magnetic pole configuration), it was heated rapidly and intensively to reach a predetermined final temperature. By two pairs of main heaters 1a and 1b arranged with heater pair 2 in between, heating is performed to a predetermined final temperature in two stages with a correction heating period in between. Therefore, thermal strain caused by rapid concentrated heating is also dispersed and reduced.

Furthermore, the excitation coils 23 for each slot of the pair 2 of the auxiliary heaters are connected to a control circuit similar to the power supply control circuit used in the above-mentioned conventional crossed magnetic field type induction heater via the respective external terminals 25. By connecting them, the power supplied to each excitation coil can be controlled, so that the desired heated portions of the plate material 3 can be individually and partially corrected and heated, and more uniform temperature control can be achieved.

Furthermore, the excitation coil 23 of the auxiliary heater can be provided only at predetermined locations when the width W of the object to be heated is constant.

In addition, in the above-mentioned embodiment, the conventional main heater is
The cross-magnetic field induction heater is divided into small main heaters each having individual magnetic poles and placed in a distributed manner, but the overall length of the cross-magnetic field induction heater, including the auxiliary heater, is not much different from the conventional one. be able to.

FIG. 3 shows another embodiment of the invention, compared to the embodiment of FIG. ) and after (downstream), and by adjusting the distribution of heating power supplied to these heaters, more precise adjustment of the heating temperature can be achieved. For example, supplying about 1/3 of the heating power supplied to all the auxiliary heaters to the first auxiliary heater pair 2a,
Approximately 1/2 of the heating power supplied to all the main heaters is supplied to the next first pair of main heaters 1a, and correction heating is performed by the second pair of auxiliary heaters 2b. Power is supplied to the main heater pair 1b to reach a temperature close to a predetermined final temperature, and the last auxiliary heater pair 2
In c, final temperature adjustment can be performed to minimize distortion.

Effects of the Invention The main heater uses a plurality of pairs having a small number of magnetic poles, that is, two magnetic poles, and these are distributed so as to be arranged alternately with the auxiliary heaters. is heated in multiple stages to reach a predetermined final temperature, so the object to be heated is not heated suddenly and intensively by the pair of main heaters, so the However, a large temperature difference does not occur, and therefore thermal strain can be kept small. In addition, since correction heating is performed by the auxiliary heater in the middle of each heating stage by multiple pairs of main heaters, the influence of temperature differences due to heating by the main heaters can be quickly compensated for, resulting in a more uniform temperature distribution. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the crossed magnetic field type induction heater of the present invention, and FIG. 2, A, B, and C are a plan view, a side view, and a sectional view of the auxiliary heater in FIG. 3 is a side view showing another embodiment of the present invention. In the figure, 1a, 1b... a pair of main heaters, 2... a pair of auxiliary heaters, 3... an object to be heated (plate material),
10, 11... Main heater, 13, 14... Excitation coil, 20, 21... Auxiliary heater, 22... Iron core, 23
...Exciting coil, 24...Slot, 25...External terminal.

Claims (1)

[Scope of Claims] 1. A cross-induction type heater having a main heater for inductively heating a conductive object to be heated by a cross-magnetic field, and an auxiliary heater for correcting and heating the insufficiently heated portion of the main heater. , the main heater includes a plurality of pairs of main heaters arranged above and below with the object to be heated in between, each having N and S magnetic poles and excitation coils associated with these magnetic poles, and the auxiliary heating A cross-magnetic field type induction heater, characterized in that the device includes at least one pair of auxiliary heaters arranged alternately with the pair of main heaters along the moving direction of the object to be heated. 2. In the cross-magnetic field type induction heater according to claim 1, the auxiliary heater has a heating element located parallel to the moving direction of the object to be heated at a location corresponding to a predetermined heating point in the width direction of the object to be heated. A crossed magnetic field type induction heater characterized in that salient poles and slots are formed in the iron core, and the excitation coil of each slot extends along the slot and is then wound along the back surface of the iron core. 3. The crossed magnetic field type induction heater according to claim 1, wherein the lamination directions of the iron cores of the main heater and the auxiliary heater are shifted by 90 degrees from each other. Heater.