JP2000030848A - Induction heating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating system capable of concentratedly heating corner sections of a heated object and capable of suppressing the power consumption required for heating. SOLUTION: A pair of iron cores 10a, 10c wound with heating coils 12a, 12c are arranged face to face across a heating object 1, another pair of iron cores 10b, 10d wound with heating coils 12b, 12d are arranged face to face across the heated object 1 perpendicularly to the layout of the iron cores 10a, 10c, and the iron cores 10a, 10b, 10c, 10d are magnetically coupled by yokes 11a, 11b, 11c, 11d. This induction heating system is carried current from a high-frequency inverter power supply so that a pair of iron cores 10a, 10c become positive poles and the other pair of iron cores 10b, 10d become negative poles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating apparatus for heating a corner of an object to be heated in a hot forging line.

[0002]

2. Description of the Related Art Generally, when hot working a steel slab, the properties of the material are greatly affected by the final working temperature. In other words, when the final processing temperature is equal to or higher than the _Ar3 point (the temperature at which transformation from austenite to ferrite starts), a relatively fine and uniform grain sized structure is obtained, and when the final processing temperature is equal to or lower than the _Ar3 point, a partially-grained mixed grain structure is obtained. At a lower temperature, a stretched grain structure mixed with a cold work structure is obtained. Therefore, in hot working,
The final processing is often completed at a temperature of _Ar3 or more. Then, the temperature is set retroactively from the final processing temperature. Note that the final processing temperature is determined by the material. In addition, when the square bar material that has been soaked and heated in a gas furnace is put into the atmosphere, the heat radiation area of the corner part is larger than the heat radiation area of the parallel part, so the temperature of the corner part is lower than others. I will. Therefore, in order to make the temperature of the corner portion of the slab be equal to or higher than the final heating temperature, the temperature on the upstream side is set higher.

Conventionally, in a process of rolling a continuously cast steel slab to produce a bar or a shaped steel, etc., the continuously cast steel slab is once cooled and then heated again to a high temperature in a heating furnace at a rolling mill and rolled. . In this case, when the molten steel melted in an electric furnace or the like is continuously cast, the completed steel slab is still at a sufficiently high temperature, and thus cooling it outdoors or the like results in enormous energy loss. Therefore, an induction heating device is used in order to heat the continuously cast steel slab without cooling and heat only the portion of the surface layer where the temperature has dropped so that the rolling can be sufficiently performed. Hereinafter, a conventional induction heating device will be described.

FIG. 8 is a sectional view showing a conventional induction heating apparatus described in, for example, Japanese Patent Publication No. 63-49858. In the drawing, reference numeral 1 denotes a heated object, 2 denotes a pinch roller for feeding the heated object 1, 3 denotes a solenoid coil for applying electric power to the heated object 1, and 4 denotes a power supply for the solenoid coil 3. In this conventional induction heating apparatus, the object to be heated 1 is conveyed into the solenoid coil 3 by the pinch roller 2 in a state where a high frequency current is supplied from the power supply 4 to the solenoid coil 3. At this time, as shown in FIG. 9, a magnetic flux φ is generated at the center of the solenoid coil 3 (that is, in a direction perpendicular to the paper surface of FIG. 9), and the outer periphery of the heated object 1 conveyed into the solenoid coil 3 The eddy current i concentrates on the surface, and the entire surface layer of the article 1 to be heated is induction-heated. Therefore, the induction heating device
Unlike the case where the entire object to be heated 1 is uniformly heated, only the surface layer is partially heated, and efficient heating can be performed at a relatively high frequency.

[0005]

Since the conventional induction heating apparatus heats the object 1 by using the solenoid coil 3 as described above, it is not suitable for heating the entire surface layer of the object 1. Are suitable. However, when the object 1 to be heated, which is produced by continuously casting steel melted in an electric furnace or the like, is discharged into the atmosphere, the temperature of the corner portion of the object to be heated 1 is reduced most. It is necessary to heat the temperature of the section to the set temperature. When the object to be heated 1 is heated by the conventional induction heating device, the object to be heated 1 is heated as a whole, and there is a problem that power consumption required for heating increases. Further, there is a problem that a portion other than the corner portion of the article to be heated 1 is heated to a higher temperature than the corner portion.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a dielectric heating apparatus capable of concentratingly heating a corner portion of an object to be heated and reducing power consumption. The purpose is to gain.

[0007]

SUMMARY OF THE INVENTION An induction heating apparatus according to the present invention comprises an iron core extending in parallel with an axial center and opposed to the axial center, and a heating coil wound around the iron core. A pair of inductors, an iron core extending in parallel with the axis and opposed to the pair of inductors with the axis interposed therebetween in a direction rotated by 90 degrees about the axis, and wound around the iron core Another pair of inductors including a heating coil, a yoke that magnetically couples the respective cores of the pair of inductors and the other pair of inductors to form a magnetic circuit, a pair of inductors having a positive electrode, and another pair of inductors A high-frequency inverter power supply for applying electric power to the heating coil so as to serve as a negative electrode is provided.

The high-frequency inverter power supply is a single power supply.

The high-frequency inverter power supply is composed of a plurality of power supplies, and is configured to synchronously apply power to a pair of inductors and a heating coil of another pair of inductors.

[0010] Further, iron cores forming a pair of inductors are configured to be movable in a direction to contact and separate from the axis, respectively, and iron cores forming another pair of inductors move to and from the axis respectively. It is configured to be movable in the direction.

[0011] Further, one pair of the pair of inductors and the other pair of inductors is configured to be movable in parallel with a direction in which the other pair of inductors oppose each other.

Position detecting means for detecting the position of the object to be heated which is continuously fed in the direction of the axis; moving means for moving the pair of inductors and the other pair of inductors;
And a control means for driving the moving means based on the detection signal of the position detecting means to adjust the positions of the pair of inductors and the other pair of inductors with respect to the object to be heated.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a sectional view showing an induction heating device according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view showing an induction heating device according to Embodiment 1 of the present invention. In each of the drawings, a pair of iron cores 10a and 10c are arranged to face each other at a predetermined distance above and below the axis.
b and 10d are disposed opposite each other with a predetermined distance left and right across the axis. Then, the heating coils 12a, 12
b, 12c, and 12d are wound around the cores 10a, 10b, 10c, and 10d disposed on the upper, lower, left, and right sides, respectively, to form inductors, and the cores 10a, 10b,
Yoke 11a, 11b, 11c, 11
The two inductors are magnetically connected to each other by d to form an inductor structure in which the four inductors are magnetically integrated. Additionally, a single high frequency inverter power supply (not shown)
Are electrically connected to the heating coils 12a, 12b, 12c, and 12d. Here, iron cores 10a arranged vertically,
The heating coils 12a, 12b, and 1 are supplied from the high-frequency inverter power supply so that 10c becomes a positive electrode (or a negative electrode) and iron cores 10b and 10d arranged on the left and right become a negative electrode (or a positive electrode).
Power is supplied to 2c and 12d.

Next, the operation of the induction heating apparatus thus configured will be described with reference to FIG. An object to be heated 1 having a rectangular cross section is transported along the axis of the induction heating device. The object to be heated 1 has a pair of iron cores 1 having upper and lower parallel surfaces.
0a and 10c, and the parallel left and right side surfaces are located between the pair of iron cores 10b and 10d. And the object to be heated 1
Are conveyed so that the centers of the cores 10a, 10b, 10c, and 10d coincide with the axes of the induction heating device, the intervals between the upper, lower, left, and right surfaces of the object 1 to be heated are all equal, and the cores 10a, 10b, The centers of 10c and 10d are located at the centers of the upper, lower, left and right surfaces of the object 1 to be heated. Therefore, the iron cores 10a and 10c arranged vertically serve as positive electrodes,
The iron cores 10b and 10d arranged on the left and right serve as the negative electrode,
Heating coils 12a, 12b,
When current is supplied to 12c and 12d, a magnetic flux φ is generated as shown by an arrow in FIG. That is, the magnetic flux φ passes from the pair of iron cores 10a and 10c to the object 1 to be heated, then to the pair of iron cores 10b and 10d, and further to the yokes 11a and 11d.
b, 11c, 11d and a pair of iron cores 10a, 10c
Flowing back to. Then, this magnetic flux φ is
, The eddy current i concentrates on the corner portion of the object 1 to be heated, and the corner portion is heated.

According to the first embodiment, it is possible to heat the corners of the object 1 in a concentrated manner without heating the entire surface layer of the object 1 to be heated. Can be heated to the set temperature.
In addition, since the corners are intensively heated, the object to be heated 1
No portion other than the corner portion is heated to a higher temperature than the corner portion. Also, the yokes 11a, 11b, 11
Since the iron cores 10a, 10b, 10c, and 10d are magnetically connected to form a magnetic circuit by c and 11d, the leakage magnetic flux of the iron core can be significantly suppressed, and the main magnetic flux penetrating the object to be heated 1 is stabilized. Can be generated. Each heating coil 12a,
Since current is supplied to 12b, 12c, and 12d, a magnetic flux can be efficiently generated in the inductor structure so as to penetrate the object 1 to be heated.
Can be efficiently heated.

Embodiment 2 In the first embodiment, all heating coils 12a,
12b, 12c, and 12d are energized,
In the second embodiment, power is supplied from four high-frequency inverter power supplies to the heating coils 12a, 12b, 12c, and 12d in synchronization with each other. In this case, when heating the article 1 to be heated, even when the capacity of one high-frequency inverter power supply is insufficient, the corner portion of the article 1 to be heated can be reliably heated to a predetermined temperature. In the second embodiment, one high-frequency inverter power supply is connected to each of the four heating coils. However, the number of high-frequency inverter power supplies is not limited to four. It may be a stand.

Embodiment 3 In the third embodiment, as shown in FIG. 4, iron cores 10a, 10b, 10c, 1
0d is slidably disposed with respect to the yokes 11a, 11b, 11c, 11d, and a pair of iron cores 10a, 10c are configured to be vertically movable by transfer devices 13a, 13c as moving means. 10b and 10d are configured to be movable in the left-right direction by transfer devices 13b and 13d as moving means. Here, the transfer device 13a,
13b, 13c, and 13d can use a hydraulic cylinder, a motor mechanism, or the like. The other configuration is the same as that of the first embodiment.

In the third embodiment, the transfer device 13a,
By activating 13b, 13c, 13d, the positions of the iron cores 10a, 10b, 10c, 10d can be independently changed. Therefore, even if the size of the object 1 changes, the upper, lower, left and right surfaces of the object 1 and the iron cores 10a, 10b, 10
c, so that the gap with 10d takes a constant value.
The positions of 10b, 10c and 10d can be adjusted respectively, the heating performance is secured, and excellent versatility is obtained.

Embodiment 4 In the fourth embodiment, as shown in FIG. 5, the yokes 11a, 11b, 11c,
11d is configured to be able to move up and down in the vertical direction by transfer devices 14a and 14b as moving means. Here, a hydraulic cylinder, a motor mechanism, or the like can be used for the transfer devices 14a and 14b. The other configuration is the same as that of the third embodiment.

The object to be heated 1 is conveyed into the inductor structure by means such as a pinch roller.
Is the height reference. Therefore, when the height of the object to be heated 1 changes, the left and right inductors, that is, the iron cores 10b, 10d
Is not located at the center of the object to be heated 1 in the height direction. In the fourth embodiment, the vertical positions of the iron cores 10b and 10d can be changed independently by operating the transfer devices 14a and 14b. , 10d and the object 1 to be heated 1 can be set to zero in the height direction, and the versatility can be further improved.

Embodiment 5 In the fifth embodiment, as shown in FIG. 6, position detecting devices 15a, 15b, 15c, and 15d as position detecting means for detecting the positions of the upper, lower, left, and right surfaces of the object 1 to be heated, respectively, include inductors. They are located on the inlet and outlet sides of the structure. Here, the position detection devices 15a, 15b, 15c, 15d
Is composed of a roller 16 and a support arm 17 that rotatably supports the roller 16 at one end. The support arm 17 elastically urges the roller 16 against the surface of the object 1 to be heated, and
The other end is attached rotatably. Then, the position of the object to be heated 1 is detected based on the rotation angle of the support rod 17. The other configuration is the same as that of the fourth embodiment.

Next, the operation of the fifth embodiment will be described. The object to be heated 1 is conveyed into the inductor structure by means such as a pinch roller. The object to be heated 1 is located on the entrance side of the inductor structure on each of the upper, lower, left, and right surfaces, and the position detectors 15a, 15b, 15c, 15d are provided.
The rollers 16 are conveyed to the outlet side while rotating the rollers 16.
When the object 1 is conveyed to the outlet of the inductor structure, the position detecting devices 15a, 15a,
While rotating each roller 16 of 5b, 15c, 15d,
It is carried out. When the object to be heated 1 is transported,
Heating coils 12a, 12b, 12 from the high frequency inverter power supply are arranged such that iron cores 10a, 10c arranged vertically serve as positive electrodes, and cores 10b, 10d arranged right and left serve as negative electrodes.
Electric power is supplied to c and 12d, and the corner portion of the article to be heated 1 is heated to a predetermined temperature.

When the object 1 is conveyed, the rollers 16 of the position detecting devices 15a, 15b, 15c, and 15d are in contact with the upper, lower, left, and right surfaces of the object 1. The rotation angle of the support arm 17 according to the size and the displacement of the support arm 17 is output. Therefore, as shown in FIG. 7, the control device 18 as a control means is provided with the position detecting device 15a,
The output signals of 15b, 15c and 15d are input,
The position of the object 1 to be heated, that is, the upper, lower, left, and right surface positions with respect to the axis is calculated from the rotation angle of 7. Then, the control device 18
Are compared with the target position and the detected position of the object 1 to be heated, and each of the transfer devices 13a, 13
b, 13c, 13d, 14a, and 14b are driven. That is, the controller 18 controls the iron cores 10a, 10b, 10c, 1
The gap between 0d and each of the upper, lower, left, and right surfaces of the object 1 to be heated is set to a set value, and the center of the iron cores 10b, 10d in the vertical direction is set to the center of the left and right surfaces of the object 1 in the vertical direction. Each transfer device 13a, 13b, 13c, 13
d, 14a and 14b are driven.

According to the fifth embodiment, the position of the object to be heated 1 is detected by the position detecting devices 15a, 15b, 15c and 15d, and the control device 18 controls the position detecting devices 15a and 15d.
b, 15c, 15d based on the output signals.
0b, 10c, 10d and the upper, lower, left, and right surfaces of the article 1 to be heated are set to the set values, and the iron cores 10b, 10c
The transfer devices 13a, 13b, and 13d are arranged such that the vertical center of d corresponds to the vertical centers of the left and right surfaces of the object 1 to be heated.
Since 13c, 13d, 14a, and 14b are driven,
The relative positional relationship between the object to be heated 1 and the iron cores 10a, 10b, 10c, and 10d is always kept constant, and the object to be heated 1 can be stably heated.

In each of the above embodiments, the core 10
Although a, 10b, 10c and 10d are arranged vertically and horizontally around the axis, the core arrangement is not limited to this, and the iron core arranged vertically and horizontally around the axis is An iron core arrangement that is rotated around by a predetermined angle may be used. In this case, the object to be heated 1 may be conveyed while being tilted so that each surface of the object to be heated 1 faces the iron core. In the fifth embodiment, the position detecting device including the roller 16 and the support arm 17 is used as the position detecting device. However, the position detecting device can detect the position of each surface of the object 1 to be heated. For example, an optical sensor that reflects the light emitted from the light emitting element on the surface of the object to be heated and receives the reflected light by the light receiving element to measure the distance to the object to be heated may be used.

[0026]

Since the present invention is configured as described above, it has the following effects.

According to the present invention, there is provided a pair of inductors each including an iron core extending in parallel with the axis and opposed to each other across the axis, and a heating coil wound around the iron core. On the other hand, another pair of inductors comprising an iron core extending in parallel with the axis and opposed to the axis in a direction rotated by 90 degrees about the axis, and a heating coil wound on the iron core. And a yoke that magnetically couples the respective cores of the pair of inductors and the other pair of inductors to form a magnetic circuit, and a heating coil such that the pair of inductors is a positive electrode and the other pair of inductors is a negative electrode. Since it has a high frequency inverter power supply that applies power,
Thus, an induction heating device capable of heating the corner portion of the object to be heated in a concentrated manner and reducing power consumption required for heating is obtained.

Further, since the high-frequency inverter power supply is a single power supply, a main magnetic flux penetrating the object to be heated can be generated stably.

The high-frequency inverter power supply is composed of a plurality of power supplies, and is configured to synchronously apply power to the heating coils of the pair of inductors and the other pair of inductors. However, it is possible to prevent a situation where the capacity of the power supply is insufficient and the heating to the predetermined temperature cannot be completed.

Further, the iron cores forming the pair of inductors are configured to be movable in the directions in which they come in contact with and separate from the axis, and the iron cores forming the other pair of inductors come in contact with and separate from the axis, respectively. Since it is configured to be movable in the direction, even if the size of the object to be heated is changed, the relative positional relationship between the inductor and the object to be heated can be adjusted to be constant.

Further, since one pair of inductors of the pair of inductors and the other pair of inductors are configured to be movable in parallel with the direction in which the other pair of inductors are opposed, the size of the object to be heated is changed. Even so, adjustment can be performed so that the relative positional relationship between the inductor and the object to be heated is constant.

Further, position detecting means for detecting the position of the object to be heated which is continuously fed in the direction of the axis, moving means for moving the pair of inductors and another pair of inductors,
Control means for driving the moving means based on the detection signal of the position detecting means to adjust the positions of the pair of inductors and the other pair of inductors with respect to the object to be heated,
The relative positional relationship between the inductor and the object to be heated can always be kept constant.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an induction heating device according to Embodiment 1 of the present invention.

FIG. 2 is a perspective view showing an induction heating device according to Embodiment 1 of the present invention.

FIG. 3 is a diagram illustrating the operation of the induction heating device according to the first embodiment of the present invention.

FIG. 4 is a sectional view showing an induction heating device according to Embodiment 3 of the present invention.

FIG. 5 is a perspective view showing an induction heating device according to Embodiment 4 of the present invention.

FIG. 6 is a side view showing a main part of an induction heating device according to Embodiment 5 of the present invention.

FIG. 7 is a block diagram showing a control unit of an induction heating device according to Embodiment 5 of the present invention.

FIG. 8 is a side view showing a conventional induction heating device.

FIG. 9 is a diagram illustrating the operation of a conventional induction heating device.

[Explanation of symbols]

1 Heated object, 10a, 10b, 10c, 10d Iron core (inductor), 11a, 11b, 11c, 11d Yoke, 12a, 12b, 12c, 12d Heating coil (inductor), 13a, 13b, 13c, 13d, 1
4a, 14b Transfer device (moving means), 15a, 15
b, 15c, 15d position detecting device (position detecting means),
18 Control device (control means).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K059 AA08 AB08 AB19 AB22 AB25 AC10 AC33 AC37 AC54 AC70 AD02 AD03 AD04 AD05 AD28 AD34 AD35 BD19 CD03 CD52 CD72 CD75 CD76

Claims (6)

[Claims] 1. An induction heating apparatus for heating an object to be heated having a rectangular cross section while continuously feeding the object in the direction of an axis, comprising an iron core opposed to the axis and extending in parallel with the axis. A pair of inductors composed of a heating coil wound around an iron core, and opposed to the pair of inductors in a direction rotated 90 degrees about the axis with the axis interposed therebetween and in parallel with the axis. Another pair of inductors comprising an extended core and a heating coil wound around the core, and a magnetic circuit is formed by magnetically coupling the pair of inductors and the cores of the other pair of inductors, respectively. An induction heating apparatus comprising: a yoke; and a high-frequency inverter power supply that applies power to the heating coil so that the pair of inductors has a positive pole and the other pair of inductors has a negative pole. 2. The induction heating apparatus according to claim 1, wherein the high-frequency inverter power supply is a single power supply. 3. The high-frequency inverter power supply comprises a plurality of power supplies, and is configured to apply power to the heating coils of the pair of inductors and the other pair of inductors in synchronization with each other. An induction heating device as described. 4. An iron core forming the pair of inductors is configured to be movable in a direction of coming into contact with and separating from the axis, and an iron core forming the another pair of inductors is respectively positioned with respect to the axis. The induction heating device according to claim 1, wherein the induction heating device is configured to be movable in a direction of coming into contact with and separating from the induction heating device. 5. The apparatus according to claim 1, wherein one pair of the pair of inductors and the other pair of inductors are configured to be movable in parallel with a direction in which the other pair of inductors oppose each other. The induction heating device according to claim 4. 6. A position detecting means for detecting a position of the object to be heated which is continuously fed in the direction of the axis, a moving means for moving the pair of inductors and another pair of inductors, and 6. A control means for driving the moving means based on a detection signal to adjust positions of the pair of inductors and the other pair of inductors with respect to the object to be heated. Induction heating equipment.