JPH0126155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for uniformly adjusting the distribution of heating temperature in a cross-magnetic field type induction heater, and relates to a device for uniformly adjusting the distribution of heating temperature in a cross-magnetic field type induction heater.
(filed on November 5, 1958).

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 field 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 object to be heated 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 above-mentioned invention related to the applicant's earlier application uses a magnetic material with low magnetic resistance to enhance the magnetic flux generated from the inductor, thereby improving or improving the non-uniform heating temperature distribution caused by the edge effect. This is something that we are trying to resolve.

The present invention aims to improve or eliminate the uneven heating temperature distribution caused by the edge effect by using a non-magnetic conductor with high magnetic resistance to attenuate the magnetic flux generated from the inductor. A regulating device is provided.

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, members that are the same or equivalent to those shown in FIG. 1 are given the same reference numerals as in FIG. 1, and their explanations will be omitted. Object to be heated with small 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, that is, overheating of the ends relative to the center, a rectangular parallelepiped as shown in Fig. Four non-magnetic conductive cores 4 (4A, 4A', 4B, 4B') made of aluminum, copper or the like are placed 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 non-magnetic conductor, the magnetic resistance of the magnetic flux passing through it increases, resulting in a decrease in magnetic flux density. That is, since the magnetic flux energy passing through the non-magnetic conductor is consumed as thermal energy due to overcurrent, the non-magnetic conductor functions to reduce the passage of magnetic flux. Therefore, the ends of the object to be heated 1A are heated more weakly 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, 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-
When 1, 4A-2, and 4A-3 are placed directly under each magnetic pole, the magnetic flux density from the magnetic poles is reduced by the core as described above, and the heating of the heated object near the core is reduced. be done. On the other hand, if the cores in FIG. 4 are moved to the positions shown in FIG. 5, that is, when each core is located between the magnetic poles,
Since it is difficult for the magnetic flux from each magnetic pole to pass through the core, which has a large magnetic resistance, the magnetic flux from the magnetic poles is not blocked, and therefore the heat generated increases. The cores of each set can be integrally moved from the position shown in Fig. 4 to the position shown in Fig. 5, and by adjusting the amount of movement, the heating of the heated object 1A can be continuously changed from weak to strong. It becomes possible to adjust. As a means for integrally moving these plurality of cores, as shown in FIG. 4, each core 4A-1, 4A-2, 4A-3 is assembled into a block 5 made of plastic material and molded to form an integral structure. and it is possible to move it using suitable e.g. cam means or screw means (not shown).

As mentioned above, when the width W' of the object to be heated is narrow, the core 4
By arranging 4A, 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 prevent overheating of the ends of 1A, and it is possible to reduce unevenness with respect to the center part. On the other hand, the width of the heated object
When W' is large, the edges are less likely to be heated than the center due to the edge effect, so the cores are arranged in the width direction as shown in Figure 2, and in the longitudinal direction as shown in Figure 5. By placing it between the magnetic poles or in a position close to them as shown in Figure 2, it is possible to intensify the heating at the ends and avoid non-uniformity with respect to the center.

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 sets of cores 4A' and 4B' are placed on the left and right in the drawing, the present invention is not limited thereto. For example, the upper cores 4A and 4A' may be placed on the right and left, respectively. Alternatively, the intended objects and effects of the present invention can be achieved even if only the lower cores 4B and 4B' are arranged on the right and left sides, respectively. In addition, as a prior art of the present invention, there is Utility Model Publication No. 371698 (Utility Model Publication No. 24-9782), but the publication describes that a diamagnetic shielding plate 5 is used for the induction hardening dielectric. ” is used and that “using a diamagnetic material (non-magnetic material) as a shielding material has a demagnetizing effect” is known.

Therefore, there are significant differences from the present invention as follows. That is, in the prior art, a non-magnetic material is simply arranged as a shielding plate, whereas in the present invention, a plurality of non-magnetic conductive cores are arranged to correspond to a plurality of magnetic poles. and place it, and
The plurality of cores are arranged so as to be integrally movable in the vertical direction.

As a result, in the present invention, each non-magnetic conductor appropriately reduces the magnetic flux from each magnetic pole so that it becomes uniform across the width, and the heating temperature distribution of the heated object is made uniform. It can be said that the effect is far superior to that of the prior art in which only one shielding plate is disposed.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1. By arranging a plurality of non-magnetic conductive cores having the following configuration between a crossed magnetic field type induction heater and an object to be heated by the induction heater. A heating temperature distribution adjusting device for a crossed magnetic field type induction heater, characterized in that the heating temperature distribution of the object to be heated can be adjusted so as to be uniform. a. The shape of each of the plurality of cores is such that the thickness gradually increases toward the end in the width direction, and the width in the longitudinal direction is approximately equal to the longitudinal width of the magnetic pole. b. Each of the cores is arranged at one or both ends of the heater in the width direction, corresponding to each of the plurality of magnetic poles arranged in the longitudinal direction of the heater. c. The plurality of cores are arranged so as to be integrally movable in the vertical direction.