JPS623556B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for uniformly adjusting the heating temperature distribution in a cross-magnetic field type induction heater.

The first cross-magnetic field type induction heater of this type
The one shown in the figure is generally used, and a pair of crossed magnetic field type induction heaters 2A and 2B are arranged above and below to heat the object 1 from above and below. Coils 3A and 3B are wound around each magnetic pole in the heaters 2A and 2B, respectively, and an alternating magnetic field is generated from each magnetic pole by alternating current applied to the coils 3A and 3B. When the heated object 1 is placed within this alternating magnetic field,
Eddy current flows through the heated object due to electromagnetic induction,
This eddy current generates Joule heat, which heats the object itself.

In such a crossed magnetic field type induction heater,
There was a problem in that the edges and the center of the object to be heated were not heated uniformly because an edge effect occurred during heating. That is, as shown by the solid line in FIG. 1, the heated object 1 has a width smaller than the width of the dielectric of the heaters 2A, 2B, that is, the width substantially equal to the width W of the heaters 2A, 2B. When heated, the edges are heated more than the center. On the other hand, in the case of the heated object 1A having a large width as shown by the dotted line, the edges are heated more than the center. There was an inconvenience that it could not be heated sufficiently. The edge effect described above relates to the width direction of the object to be heated, but the same edge effect also occurs in the vertical direction. In other words, if the vertical width of the heated object is smaller than the magnetic pole spacing of the dielectric (the spacing between the N pole and the S pole), the ends of the object will be overheated, and if it is larger, the ends will not be heated. There were enough inconveniences.

The present invention provides an adjustment device that attempts to improve or eliminate the non-uniformity of heating temperature distribution caused by such edge effects.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the cross-magnetic field type induction heater shown in FIG. 2, the same or equivalent members as those shown in FIG. 1 are given the same reference numerals as in FIG. 1, and the explanation thereof will be omitted. Object to be heated with large width dimension 1
When A is placed between the heaters 2A and 2B, in order to avoid uneven temperature distribution due to the edge effect mentioned above, it is necessary to use a ferrite, for example, in the shape of a rectangular parallelepiped cut along the diagonal of the side surface as shown in Fig. 3. Four magnetic cores 4 4A, 4A', 4B, and 4B' are arranged at the end of the object to be heated 1A as shown in FIG. Two cores, designated 4A and 4A', are arranged as a set at both ends. Due to the presence of the core made of a magnetic material, the magnetic resistance of the magnetic flux passing through it decreases, resulting in an increase in magnetic flux density. Therefore, the ends of the object to be heated 1A are heated more strongly than in the case where there is no core, and therefore it is possible to heat the object almost uniformly with the center. Note that it is desirable to be able to adjust the position of the core in accordance with the width W' of the object to be heated, and for this purpose, for example, screw means or cam means (not shown) can be used.

Referring to FIG. 4, the manner in which the cores are arranged in the vertical direction becomes clear. That is, three cores 4A
-1, 4A-2, and 4A-3 are arranged at the same intervals as the magnetic poles N, S, and N arranged at the pole pitch 2P. Since FIG. 4 shows only the upper heater 2A and omits the illustration of the lower heater, in the embodiment of FIG. 2, six cores are used for the upper heater 2A, Similarly, 6 cores are used for the lower heater 2B, for a total of 12 cores. As shown in Figure 4, core 4A-
1, 4A-2, and 4A-3 are placed directly under each magnetic pole, the magnetic flux density from the magnetic poles is increased by the core as described above, and the heated object near the core becomes high temperature. On the other hand, if we move the cores in Figure 4 to the positions shown in Figure 5, that is, when each core is located between magnetic poles, the magnetic flux from each magnetic pole passes through the core with less magnetic resistance. The heat generated by the magnetic flux from the magnetic poles is reduced.
By making each set of cores movable from the position shown in FIG. 4 to the position shown in FIG. 5, it becomes possible to continuously adjust the heating of the object to be heated 1A from strong to weak. As a means for integrally moving these plurality of cores, as shown in Fig. 4, each core 4A-
1, 4A-2, 4A-3 can be incorporated into a block 5 of e.g. plastic material and molded into an integral construction, which can then be assembled using suitable e.g. cam or screw means (not shown). It is possible to move it.

As described above, when the width W' of the object to be heated is wide, the core 4
By arranging A, 4B, 4A', and 4B' as shown in Fig. 2, and arranging them in the longitudinal direction directly under or close to the magnetic poles as shown in Fig. 4, the object to be heated can be heated. It is possible to sufficiently heat the ends of 1A, and it is possible to reduce non-uniformity between the ends and the center. On the other hand, the width of the heated object
When W' is small, the edges are more likely to be overheated than the center due to the edge effect, so the core is placed as shown in Figure 2 in the width direction, that is, the core is placed at the edge of the heated area. without getting close to the
By arranging the magnetic poles in the vertical direction as shown in Figure 5, by placing them between the magnetic poles or in a position close to them, it is possible to prevent overheating of the ends and avoid unevenness with the center. Become.

In the embodiments described above, the shape of the core was explained as shown in FIG. 3, but the present invention is not limited to this shape, and the slope shown in FIG. 3 may be curved, for example, instead of a straight line. No problem.
That is, it is sufficient that the heater has a shape in which the thickness gradually increases toward the ends in the width direction of the heater, and the vertical width is approximately equal to the vertical width a of the magnetic pole. Further, although a pair of upper and lower heaters is shown in the embodiment, the desired effects of the present invention can be achieved with either one of the heaters.

Furthermore, in the embodiment shown in FIG.
Two sets of two cores, namely cores 4A and 4B
Although the case has been described in which the set of cores 4A' and 4B' are installed on the left and right sides of the drawing, the present invention is not limited thereto.
A and 4A' may be arranged on the left and right, respectively, or even if only the lower cores 4B and 4B' are arranged on the left and right, respectively, the intended purpose and effect of the present invention can be achieved. be.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a conventional cross-magnetic field type heater, FIG. 2 is a front view showing an embodiment of the present invention, FIG. 3 is a perspective view showing a magnetic core, and FIGS. 4 and 5. FIG. 2 is a side view showing the arrangement relationship between magnetic poles and magnetic cores in the embodiment. 1, 1A... Heated object, 2A, 2B... Heater, 3A, 3B... Coil, 4, 4A, 4B...
Magnetic core, 5...Plastic member, S, N...
...Magnetic pole, 2P...pole pitch.

Claims (1)

[Scope of Claims] 1. A cross-magnetic field induction heater having a plurality of magnetic cores disposed between a cross-magnetic field induction heater and an object to be heated by the induction heater, the cores extending in the width direction of the heater. at one end or both ends thereof, the cores are disposed corresponding to each of the plurality of magnetic poles arranged in the longitudinal direction of the heater, and the plurality of cores are movable integrally in the longitudinal direction. Therefore, the heating temperature distribution adjusting device for a crossed magnetic field type induction heater is characterized in that the heating temperature distribution of the object to be heated can be adjusted so as to be uniform. 2. A device according to claim 1, which
The shape of the magnetic core gradually increases in thickness toward the end in the width direction of the heater,
A heating temperature distribution adjusting device for a crossed magnetic field type induction heater, characterized in that the width in the vertical direction is approximately equal to the vertical width of the magnetic pole.