JPH0456093B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an induction heating device, and particularly to an induction heating device suitable for continuous induction heating of strip-shaped metal materials (plates, foils).

[Conventional technology]

In a typical induction heating device, an inductor or heating coil is provided in close proximity to a conductive substance. An alternating magnetic field is generated in the heating coil, and eddy currents are generated in the conductive material by electromagnetic induction. Due to the electric resistance R inherent in the conductive material, Joule heat ² R is generated in the conductive material.

Traditionally, for example, Japanese Patent Publication No. 55-36250 and Japanese Patent Publication No.
As disclosed in No. 51-138937, an induction heating device is used for annealing a band-shaped metal material.
As a method for applying the induction heating method to heating such a strip-shaped metal material, the longitudinal magnetic flux heating method shown in FIG.
There are two methods: heating method) and transverse flux heating method (transverse flux heating method) shown in FIG.

An example of the orthogonal magnetic flux heating method is shown in FIG.
In the figure, 1 and 2 are arranged facing each other with a certain distance apart, and have recesses 1s and 2s on the opposing surfaces at a certain distance.
iron cores 1a and 2a in which are formed an induction heating coil 1b that is housed in each of the recesses 1s and 2s and is wound in a substantially quadrilateral shape so that the winding start and winding end are pulled out from positions close to each other; 2b
These are the opposing upper and lower sides of the induction heating inductor. 5 is induction heating inductor 1, 2
This is a band-shaped metal material that undergoes induction heating treatment while moving through the space between the two.

Since the orthogonal magnetic flux heating method uses the iron cores 1 and 2, when the metal material 5 to be subjected to induction heating treatment is a magnetic material, the iron cores 1 and 2 are
Since the metal material 5 is attracted to the metal material 5 and the running is significantly inhibited, the orthogonal magnetic flux heating method is not suitable for aluminum,
Used for heating non-magnetic materials such as austenitic stainless steel.

[Problem that the invention seeks to solve]

FIG. 9 shows a cross-sectional view and a distribution state of the secondary current 2 generated in the band-shaped metal material 5 when a band-shaped metal material 5 such as austenitic stainless steel is induction-heated by the orthogonal magnetic flux heating method. The band-shaped metal material 5 has opposing cross-sectional "concave" shaped cores 1a, 2a.
Proceed in the direction of arrow a between the two. The magnetic flux φ is generated, for example, in the direction of the illustrated arrow to form a magnetic circuit.
Due to the magnetic flux φ generated as shown in FIG. 91, a secondary current 2 as shown in FIG. 92 is generated in the band-shaped metal material 5. This secondary current 2 heats the band-shaped metal material 5 . While being heated in this manner, the band-shaped metal material 5 moves in the direction of the arrow a. As a result, most of the band-shaped metal material 5 in the width direction is heated with uniform temperature distribution.

However, in the edge portion 5a of the band-shaped metal material 5,
In addition to this, heating is added due to the secondary current flowing in the longitudinal direction of the edge portion. As a result, the edge portion 5a
will overheat, making uniform heating in the width direction difficult.

Even with such a conventional method, as shown in FIG.
2a, a substantially uniform heating pattern can be obtained. However, in the conventional method, when the iron cores 1a, 2a are arranged so that the ends of the iron cores 1a, 2a are approximately equal to or outside the edges of the band-shaped metal material 5, as described above, It was not possible to avoid overheating of the edge portion 5a.

As explained above, in induction heating of a strip metal material using the orthogonal magnetic flux heating method, it is difficult to uniformly heat the strip metal material in the width direction.
The two disadvantages are that it is difficult to uniformly heat various strip metal materials having various widths with the same induction heating inductor. Tokukai Akira
55-36250 (referred to as known example 1) and Special Publication No. 55-
36250 (referred to as Known Example 2) is a proposal for an apparatus that aims to eliminate these drawbacks and perform uniform induction heating in the width direction of a strip-shaped metal material by an orthogonal magnetic flux heating method. FIG. 10 shows the induction heating device cut in the width direction of the band-shaped metal material 5, and centering on the band-shaped metal material 5, an upper region, a lower region, a left side region,
The figure is divided into five main areas: the right side area and the space area required for the strip-shaped metal material 5 to move in its longitudinal direction. Of course, known example 1 and known example 2
The induction heating device used in the invention can also be divided into at least five main areas as shown in FIG. The points that the induction heating inductors used in the known examples 1 and 2 have in common are 1) iron cores 1a and 2a as shown in FIG. 8, and an induction heating coil 1;
2) In order to control the magnetic flux density of the edge portion 5a of the strip-shaped metal material 5, the known examples 1 and 2 each have an iron core attached with a magnetic flux control member having characteristics. 1a, 2a; 3) iron core 1a with attached magnetic flux control member;
2a belongs to the upper and lower regions of the five regions in FIG. 10 and does not belong to the left and right regions, and 4) that the band-shaped metal material 5 belongs to the region. There are two points. That is, in the conventional orthogonal magnetic flux heating methods including the known examples 1 and 2, the magnetic flux density of the edge portion 5a of the band-shaped metal material 5 is controlled to be uniform in the left side region and right side region shown in FIG. No flux control members or devices were provided for heating.

[Means for solving problems]

The main purpose of the present invention is to solve the drawback that it is difficult to uniformly heat the strip metal material in the width direction in the induction heating of the strip metal material using the orthogonal magnetic flux heating method, and to always uniformly heat the strip metal material with different widths. An object of the present invention is to provide an induction heating device that is different from the known examples 1 and 2 and is capable of heating.

The gist of the present invention is to provide an induction heating device for inductively heating a band-shaped metal material while running it longitudinally, which includes iron cores that are arranged facing each other at a predetermined distance apart, and that have recesses formed on the opposing surfaces at a predetermined distance. , between the opposing upper and lower sides of an induction heating inductor that is housed in each of the recesses and is wound in a substantially quadrilateral shape so that the winding start and winding end are pulled out from positions close to each other. A magnetic flux concentrating member is provided at a position covering both ends of the strip-shaped metal material in the width direction, and the magnetic flux concentration members are movable in the width direction and the longitudinal direction of the strip-shaped metal material, or in both directions. An induction heating device is provided which is connected to the device.

[Embodiment] FIGS. 1 and 2 show a side sectional view and a front sectional view of an induction heating device according to an embodiment of the present invention. This embodiment is an induction heating device that inductively heats a band-shaped metal material 5 while traveling in its longitudinal direction, which are arranged opposite to each other at a certain distance apart, and recesses 1s and 2s are formed on the opposing surfaces at a predetermined distance. iron cores 1a, 2
a, and induction heating coils 1b and 2b that are housed in respective recesses 1s and 2s and are wound in a substantially quadrilateral shape so that the winding start and winding end are pulled out from positions close to each other. A "co" is placed between the upper side 1 and the lower side 2 facing toward each other, and at a position covering both ends of the band-shaped metal material 5 in the width direction.
The "U"-shaped magnetic flux concentration members 61, 62 are provided, and the "U"-shaped magnetic flux concentration members 61, 62 are connected to movement adjustment devices 71, 72 that are movable in the width direction and the longitudinal direction of the strip-shaped metal material 5, and in both directions. It is that you are.
Of course, for simplicity, it is also possible to determine the position in advance and make it semi-fixed between the inductors 1 and 2 on the upper and lower sides. Furthermore, the present invention is known in the known example 1 and the known example 2.
The difference is that the iron cores 1a and 2a of the present invention are conventionally used and do not include a special magnetic flux control member, and that the "U"-shaped magnetic flux concentration members 61 and 62 are the same as those shown in FIG. This point belongs to the left side area and the right side area shown in FIG.

The shape and dimensions of the "U"-shaped magnetic flux concentration members 61, 62 will be explained in more detail with reference to FIG. FIG. 2 shows a partially enlarged front view of the right side of the induction heating device of this embodiment. The shape of the magnetic flux concentration members 61 and 62,
The dimensions shall be symmetrical.

Width w of the portion where the concave portion of the “U”-shaped magnetic flux concentrating members 61, 62 and the end of the band-shaped metal material 5 passing between the concave portions overlap, the “U”-shaped magnetic flux concentrating members 61, 6
2, the gap g2 between the inner surface of the vertical part c of the U-shaped magnetic flux concentrating members 61 and 62 and the edge E of the band-shaped metal material 5,
The length Ly of the U-shaped magnetic flux concentration members 61 and 62, and the length Ly of the U-shaped magnetic flux concentration members 61 and 62 and the iron core 1a,
The air gap distances g3 and g4 between 2a and 2a will be explained.
g1 and g2 are the running of the band-shaped metal material 5 which is induction heated while running in a space mainly surrounded by the induction heating inductors 1 and 2 and the "U" shaped magnetic flux concentrating members 61 and 62 that constitute the induction heating device of the present invention. Related to sex. g1 is made larger than the thickness t of the band-shaped metal material 5 so that the end of the band-shaped metal material 5 passes through the center between the upper and lower horizontal parts a and b of the U-shaped magnetic flux concentration members 61 and 62. Increasing g1 improves the runnability of the strip metal material 5, but it also increases the distance Gc between the induction heating inductors 1 and 2 on the opposing upper and lower sides, making it difficult for the strip metal material 5 to be heated. It is preferable not to make it unnecessarily large. g2 is selected with particular consideration to the maximum meandering amount s of the running belt-shaped metal material 5 so that the end of the belt-shaped metal material 5 does not come into contact with the vertical part c of the U-shaped magnetic flux concentration members 61, 62 while running. It is preferable. Generally, it is preferable to provide a margin of 10 mm or more relative to the maximum meandering amount s. g3 and g4 are "ko"
The upper side where the letter-shaped magnetic flux concentration members 61 and 62 face each other,
This is a necessary gap that moves in the width direction of the band-shaped metal material 5 between the induction heating inductors 1 and 2 on the lower side. g3,
Similar to g2, g4 is also preferably kept to the minimum necessary so as not to increase Gc.

Next, w will be explained, where w is the band-shaped metal material 5
related to the uniformity of temperature distribution in the width direction, especially at the edges. w will be explained using a schematic diagram in FIG. FIG. 3 is a diagram showing the temperature distribution in the width direction of the band-shaped metal material 5 obtained by induction heating. Temperature distribution A
is a U-shaped magnetic flux concentration member 6 using the induction heating inductors 1 and 2 constituting the induction heating device of the present invention.
1 and 62 are not provided. B is a target temperature band when there is a uniform heating condition of target temperature T (°C) and allowable temperature range ±ΔT/2 (°C). If We is the distance between the intersection P of the upper limit of the target temperature band B and the temperature distribution A and the edge E of the band-shaped metal material 5, then
Empirically, it is preferable that the width w of the portion where the recesses of the U-shaped magnetic flux concentrating members 61 and 62 and the end of the band-shaped metal material 5 that passes near the recesses wraps is less than We, and w is within that range. If selected, band-shaped metal material 5
The uniformity of the temperature distribution in the width direction was improved. Once w is determined, the width Wy of the upper and lower horizontal portions a and b of the U-shaped magnetic flux concentration members 61 and 62 becomes Wy=w+g2. The sign of w is a positive sign when the band-shaped metal material 5 and the U-shaped magnetic flux concentration members 61 and 62 overlap, and a negative sign when they do not overlap.

Next, I will explain about Ly. Similar to w, Ly is related to the uniformity of the temperature distribution in the width direction of the band-shaped metal material 5, particularly at the end portions. "U" shaped magnetic flux concentration members 61, 6
2 is provided to control the magnetic flux during induction heating of the band-shaped metal material 5 so as to disperse the secondary current concentrated at the edge portion 5a of the band-shaped metal material 5 shown in FIG. "U" shaped magnetic flux concentration member 61,
62 is the opposing upper side 1 of the induction heating inductor;
Since it is provided to control the magnetic flux that is located between the lower side 2 and contributes to the induction heating of the material to be heated 5, the length Ly of the "U"-shaped magnetic flux concentration members 61 and 62 is equal to that of the iron cores 1a and 2a. Make it approximately equal to the length Lc. In addition to the "U"-shaped magnetic flux concentrating member described in the embodiment, as shown in FIG. 4, for example, a ">"-shaped magnetic flux concentrating member, a "□"-shaped magnetic flux concentrating member, etc. can also be selected. In addition, "U" shaped magnetic flux concentration members 61, 62
In addition to making the length Ly approximately equal to the length Lc of the iron cores 1a and 2a, as shown in FIG. A sandwiching structure can also be used.

As the material of the "U"-shaped magnetic flux concentration members 61 and 62, a laminated iron core, a linear bundled iron core, a sintered molded iron core such as a ferrite core, etc. are used. Also,
The "U"-shaped magnetic flux concentrating members 61 and 62 generate some heat due to iron loss during heating, so it is preferable to use a water-cooled or air-cooled cooling structure to remove the heat.

Examples of implementing the present invention will be specifically described below. Austenitic stainless steel (1.0 mm thickness x 300 mm width) of band-shaped metal material 5 was heated continuously at a rate of 1 m/min. The length Lc, width Wc, and gap Gc of the upper and lower sides of the bipolar cores 1a and 2a on the opposing upper and lower sides are 200 mm, 600 mm, and 900 mm, respectively, the heating frequency is 500 Hz, and the target temperature range is 200°C ~
The temperature was 230℃. Also, g1, g2, g3 and g4 are each 30
mm, 30mm, 10mm, and 10mm. Ly was 200 mm, the same length as Lc.

FIG. 6 shows the temperature distribution in the width direction of the strip-shaped metal material under various installation conditions of the U-shaped magnetic flux concentration members 61 and 62 in the embodiment. In the case where the U-shaped magnetic flux concentrating members 61 and 62 are not provided, the temperature distribution in the width direction of the band-shaped metal material 5 is such that the temperature at the center of the band-shaped metal material 5 in the width direction is the lower limit of the target temperature band, that is, 200
The output of the power supply was adjusted so that the temperature was close to ℃. As a result of the heating, as shown in FIG. 6, the end portion of the band-shaped metal material 5 was overheated, exceeding the target temperature range of 200°C to 230°C to reach 300°C. Obtained band-shaped metal material 5
Distance from the intersection P of the width direction temperature distribution and the target temperature band upper limit of 230°C to the edge E of the band-shaped metal material 5
We were 30mm. From this result, w is 30mm, 10
Heating was performed in three cases: mm and 0 mm.
As shown in FIG.
If 1 and 62 are not provided, the edge temperature of the strip metal material 5 is 300°C and the target temperature range is 200°C to 230°C.
However, by providing the U-shaped magnetic flux concentrating members 61 and 62 according to the present invention, overheating of the edge portion of the strip metal material 5 can be suppressed, especially when w is 10 mm. The entire widthwise direction of material 5 fell within the target temperature range of 200°C to 230°C, and the uniformity of the heating temperature was dramatically improved.

〔Effect of the invention〕

As explained above, by using the induction heating device of the present invention, it is possible to disperse the secondary current that concentrates on the edge portion of the strip-shaped metal material, and it is also possible to uniformly heat strip-shaped metal materials with different widths using the same heating inductor. became possible. As a result, the present invention can be advantageously applied to heat treatment of band-shaped metal materials, drying and baking of coating films, and other techniques related to heating of band-shaped metal materials.

[Brief explanation of the drawing]

1 is a schematic side view showing the present invention, 2 is a schematic front view, FIG. 2 is a partially enlarged view of FIG. FIG. 5 is an explanatory diagram of a specific example of a magnetic flux concentrating member different from the example, FIG. 5 is an explanatory diagram of a specific example of dividing a magnetic flux concentrating member different from this embodiment, and FIG. 6 is a strip metal under the installation conditions of the magnetic flux concentrating member of the present invention. An example of temperature distribution in the width direction of the material, Figure 7 1 is a principle diagram of the conventional longitudinal magnetic flux heating method, Figure 7 2 is a principle diagram of the orthogonal magnetic flux heating method, and Figure 8 is a schematic explanation of the orthogonal magnetic flux heating method. Figure 9 is an explanatory diagram of a specific example of the orthogonal magnetic flux heating method, Figure 9 2 is a secondary current distribution characteristic diagram for explaining the effect of Figure 9 1, and Figure 10 is based on the orthogonal magnetic flux heating method. It is a main area division diagram of an induction heating device. In the figure, 5 is a strip-shaped metal material, 1 and 2 are induction heating inductors, and 61 and 62 are U-shaped magnetic flux concentration members.

Claims (1)

[Scope of Claims] 1. In an induction heating device for inductively heating a strip-shaped metal material while running it in its longitudinal direction, an iron core that is disposed opposite to each other at a predetermined distance and has a concave portion formed on its opposing surface; Between the opposing upper and lower sides of an induction heating inductor that is housed in each recess and is wound in a substantially quadrilateral shape so that the winding start and winding end are pulled out from close positions. , An induction heating device comprising magnetic flux concentrating members at positions covering both widthwise end portions of the strip-shaped metal material. 2. The induction heating device according to claim 1, wherein the magnetic flux concentrating member is connected to a movement adjustment device that is movable in the width direction and the longitudinal direction of the strip-shaped metal material, and in both directions.