JP2532826Y2 - Electric heating device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric heating apparatus in which a material to be heated having electric conductivity is continuously supplied and is electrically heated. For example, the present invention relates to various heat treatments such as quenching a strip steel sheet and annealing. Heating device used when heating for heating.

[0002]

2. Description of the Related Art Conventionally, as a device for heating a strip-shaped steel sheet for various heat treatments such as quenching and annealing, an energizing roll is brought into contact with a strip-shaped steel sheet continuously fed, and the strip-shaped steel sheet is formed from the energized roll. There is an electric heating device in which electric power is supplied to electrically heat the strip-shaped steel sheet. In such an electric heating device, in order to secure the electric current necessary for heating between the electric roller and the strip-shaped steel sheet, generally, a roll pair composed of an electric roller and an electric roller or a holding roll and an electric roller are used. The belt-shaped steel sheet is sandwiched between the roll pairs made of, and a rolling force is applied to the roll pair so that the current-carrying roll and the belt-shaped steel sheet are surely brought into contact with each other. For example,
Japanese Patent Application Laid-Open No. 61-242768 discloses that when a steel strip (rolled material) is energized by using an energizing roll to heat the steel strip, a rolling force is applied to the energizing roll by a cylinder to reduce the strip steel by 1%. It is disclosed that rolling is performed at the above-described rolling reduction.

[0003]

By the way, this kind of strip-shaped steel sheet, which is continuously heated while being supplied with electric current, usually has a thickness deviation of about 1% at each position in the longitudinal direction. On the other hand, in order to make the rolling reduction almost constant as in the known example, it is necessary to use a liquid (oil pressure) as the working fluid of the cylinder. However, since the liquid is incompressible, even if there is a thickness variation at each position in the longitudinal direction of the strip-shaped steel sheet, the gap between the roll pairs generates only a slight displacement according to the rigidity of the machine including the cylinder support structure. Absent. in this way,
In a non-compressible pressure reduction device such as a conventional liquid cylinder,
Since the gap between the roll pairs hardly changes even if the thickness of the strip-shaped steel sheet changes, there is a problem that the fluctuation of the rolling force becomes very large, causing plastic deformation of the strip-shaped steel sheet and remarkably deteriorating the shape. Was.

Accordingly, the present invention is intended to minimize the fluctuation of the rolling force even when the thickness of the steel strip changes when the rolling force is applied to the pair of rolls contacting the continuous feeding of the steel strip. It is an object of the present invention to provide a current-carrying heating device.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a strip-shaped steel plate, in which at least one of a pair of rolls is a material to be heated which is continuously fed a pair of rolls composed of energized rolls. In the electric heating device, which is brought into contact with the roll pair by applying a reduction force to the roll pair by the reduction means, and the belt-shaped steel sheet is electrically heated, the reduction means has compressibility with respect to the reduction force, and the thickness variation of the strip-shaped steel sheet. The gap between the pair of rolls is configured to be displaceable according to the following formula, and the pair of rolls includes an energizing roll and a pressing roll that can be elastically deformed in the radial direction. In addition, as the compressing reduction means, a gas cylinder, a mechanical spring, a series combination of a gas cylinder and a mechanical spring, a series combination of a liquid cylinder and a mechanical spring, or the like can be used.

[0006]

According to the present invention constructed as described above, since the rolling-down means has compressibility with respect to the rolling-down force, even if the thickness of the strip-shaped steel sheet fluctuates, the magnitude of the fluctuation of the rolling-down force hardly increases. The gap between the roll pairs is displaced in a negligible state. For example, bore 1
When a 50 mm gas cylinder with a stroke of 100 mm is used, assuming that the thickness of the strip-shaped steel sheet is 1 mm and the variation rate of the thickness is 2% of the thickness, when the gap between the roll pairs changes with the thickness variation. Since the fluctuation rate of the rolling force is P × volume V = constant, P ′ / P = V / V ′ = 100/100 (1−0.02) ≒ 1.02, and the fluctuation rate of the rolling force is the thickness. And the variation of the rolling force due to the thickness variation does not cause plastic deformation of the strip-shaped steel sheet. Also, when a mechanical spring is used, the rate of change of the rolling force is substantially equal to the rate of change of the thickness.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an electric heating apparatus to which the present invention is applied. First, FIG. 4 shows the entire apparatus, and a set of roll pairs 20 and 30 are provided at predetermined intervals along a feed path L of a strip-shaped steel sheet 10 which is a material to be heated.
Is arranged. These roll pairs 20 and 30 are respectively composed of a pair of a press roll 21 and a current roll 22 and a pair of a press roll 31 and a current roll 32, and are arranged to face each other with the strip-shaped steel plate 10 therebetween. In addition, each roll 21,22,31,32 has a shaft 211,221, respectively.
311 and 321 are rotatable around the
In some cases, the motors 2 and 32 are rotated by a motor in synchronization with the continuous feeding of the belt-shaped steel sheet 10 in the direction of the arrow.

The press roll 21 is a non-conductive roll having a surface lined with an elastic rubber layer or the like, and the press roll 31 is a non-conductive roll having a heat-resistant metal layer or the like laminated on a lining such as an elastic rubber layer. In both cases, the vicinity of the surface is configured to be elastically deformable in the radial direction. Then, the pressing rolls 21 and 31 are moved to the shaft 21 by a pressing means 40 described later.
The rolling force P is applied to both ends of the strips 1 and 311, so that the stripping steel sheet 10 is pressed against the strip-shaped steel sheet 10.

Next, in the apparatus of this embodiment, an annular transformer 50 is arranged around the outer periphery of the strip-shaped steel sheet 10 between the pair of rolls 20 and 30 as a means for supplying electricity to the strip-shaped steel sheet 10. The annular transformer 50 includes, for example, an annular core 51 formed by forming a silicon steel plate having a suitable property as a magnetic path into a rectangular annular shape and laminating the annular core to a predetermined length.
And a primary coil 52 wound along the inner and outer peripheries. In the ring of the annular core 51, a steel strip 1
0 is inserted. The primary coil 52 of the annular transformer 50 is connected to an AC power supply 60 having a power control switch.

In this apparatus, the energizing roll 2
Each of the shafts 221 and 321 has a power receiving unit, and the slider 71 is in sliding contact with each of the power receiving units. A conductive member (so-called bus bar) 70 is provided between the pair of sliders 71, thereby electrically connecting the current-carrying rolls 22 and 32. As the conductive member 70, a good conductive material such as a copper material having a predetermined width and thickness is used. Here, the energizing rolls 22, 3
The relationship between the electrical resistance R1 of the strip-shaped steel plate 10 and the electrical resistance R2 of the conductive member 70 between the two is set to R1 >> R2. The conductive member 70 is disposed above and below the annular transformer 50 and the strip-shaped steel plate 10 at substantially equal intervals, and is integrally connected near the energizing rolls 22 and 32 to be connected to the slider 71.

FIGS. 1 to 3 show an embodiment of the screw-down means 40. FIG. In addition, the roll pair 20 on the heating entrance side
In the following, a description will be given of the pressing means 40 for the roll pair on the heating output side.

FIG. 1 shows a first embodiment, in which a pneumatic cylinder 401 is used. This pneumatic cylinder 4
Reference numeral 01 is attached to the upper end of the fixed frame 402, and its piston rod 401 a is connected via a pin 404 to a bearing 403 supporting the shaft 211 of the presser roll 21. The bearing 403 is slidably engaged with the fixed frame 402. Solenoid valves 405 and 406 are provided in an air supply passage and an exhaust passage of the pneumatic cylinder 401, respectively, and solenoids 405 a and 406 a of the solenoid valves 405 and 406 are connected to a switching control unit 407. The switching control unit 407 receives a line stop signal and a line start signal from a main control device 408 that controls the entire equipment. The switching control unit 4 based on these signals
07 controls the solenoids 405a, 406a, thereby opening or closing the solenoid valves 405, 406.

FIG. 2 shows a second embodiment, in which a compression coil spring 411 is used. A motor 412 is attached to an upper end of the fixed frame 402, and a compression coil spring 411 is disposed between a lower end of a screw 413 that is driven to rotate by the motor 412 and a bearing 403. Therefore, the screw 413 by the motor 412
, The spring force of the compression coil spring 411 can be adjusted. In this example, the motor 412 is controlled by the switching control unit 407.

FIG. 3 shows a third embodiment, in which the pneumatic cylinder 401 and the compression coil spring 411 as described above are used.
Are used in series. Compression coil spring 41
1 is disposed between the lower end of the piston rod 401 a of the pneumatic cylinder 401 and the bearing 403. The control system in this example is the same as in the first embodiment.

Although not shown, as a fourth embodiment,
A hydraulic cylinder can be used instead of the pneumatic cylinder 401 in the third embodiment.

Referring to FIG. 4, when the primary voltage 52 is applied from the AC power supply 60 to the primary coil 52 of the annular transformer 50, the electric heating device is inserted into the ring of the primary coil 52 in FIG. Since the strip-shaped steel sheet 10 functions as a secondary coil, a secondary voltage is induced in the strip-shaped steel sheet 10. A conductive member 70 is provided between the energizing rolls 22 and 32.
Is electrically connected by the
A short circuit is formed by the strip-shaped steel sheet 10 and the conductive member 70 via the wires 2 and 32, and the secondary current generated in the strip-shaped steel sheet 10 flows through the conductive member 70 as a return line. The secondary voltage induced in the strip-shaped steel sheet 10 is consumed by the voltage drop in the strip-shaped steel sheet 10 and the voltage drop in the conductive member 70. (Electrical resistance of the strip-shaped steel sheet 10) >> (Electrical resistance of the conductive member 70) , Most of the secondary voltage is consumed for heating the strip-shaped steel sheet 10, and the loss in the conductive member 70 is extremely small. Thus, the belt-shaped steel sheet 10 is heated with electric current extremely efficiently.

1 to 3, the pressing roll 21 is lowered by the pressing means 40 in FIGS. 1 to 3, but the pneumatic cylinder 401 and the compression coil spring 41 are used.
1. The series combination of the pneumatic cylinder 401 (or the hydraulic cylinder) and the compression coil spring 411 has a compressibility with respect to the rolling force P. Therefore, even if the thickness of the continuously fed strip-shaped steel sheet 10 fluctuates, the gap between the presser roll 21 and the energizing roll 22 is displaced in a state where the magnitude of the fluctuation of the rolling force P is almost negligible. The variation rate of the rolling force P when the gap between the presser roll 21 and the energizing roll 22 changes with the variation of the sheet thickness is substantially equal to the variation rate of the thickness. Does not cause plastic deformation of the strip-shaped steel plate 10.

As in the present embodiment, the energizing roll 22
The roll pair 20 composed of the press roll 21 and the press roll 21 which can be elastically deformed in the radial direction has one object to prevent the strip steel plate 10 from being plastically deformed by elastically deforming the press roll 21. Therefore, the pressing means 40 having compressibility is used.
By displacing the gap between the presser roll 21 and the energizing roll 22 without substantially changing the rolling force P by using the above, the advantage of using the elastically deformable presser roll 21 can be fully utilized.

In the meantime, when the line is stopped due to equipment failure or the like during the energization heating, the main control unit 408 sends a line stop signal to the switching control unit 407 almost simultaneously with the line stop in FIGS. On the basis of this signal, the switching control unit 407 causes the solenoids 405a, 40
6a is controlled to close the electromagnetic valve 405 in the air supply path and open the electromagnetic valve 406 in the exhaust path. Further, in FIG. 2, the switching control unit 407 controls the motor 412 based on a line stop signal from the main control device 408,
The compression screw spring 41 is rotated by rotating the screw 413.
Release the spring force of 1. By this, presser roll 2
The pressing force P to 1 is released, and the presser roll 21 comes into contact with the strip-shaped steel plate 10 only by its own weight. Accordingly, it is possible to prevent the elastic rubber layer of the presser roll 21 from being locally flattened during the line stoppage.

When the line is started after the line is stopped, in FIGS. 1 and 3, the main control unit 408 sends a line start signal to the switching control unit 407 almost simultaneously with the line start, and based on this signal. Switching control unit 407
Controls the solenoids 405a and 406a to open the solenoid valve 405 in the air supply passage and close the solenoid valve 406 in the exhaust passage. In FIG. 2, the main controller 4
Switching control unit 40 based on the line start signal
7 controls the motor 412 and rotates the screw down screw 413 to apply a spring force to the compression coil spring 411.
Thus, the rolling force P is applied almost simultaneously with the start of the line,
Even if the energization is started at the same time when the required rolling force is reached, there is no variation in rolling force due to local flattening of the presser roll 21.
No spark is generated between the belt-shaped steel sheet 10 and the energizing roll 22.

As described above, the embodiment of the present invention has been described.
The present invention is not limited to the above embodiment, and various effective changes and applications are possible based on the technical idea of the present invention. For example, in the embodiment, the roll pair is constituted by the pressing roll and the energizing roll, but may be a pair of the energizing roll and the energizing roll. In the embodiment, the configuration is described in which the belt-shaped steel plate is heated by inducing a voltage by the annular transformer. However, a configuration in which power is supplied directly from the power supply means (AC power supply and transformer) to both energizing rolls may be used.

[0022]

[Effects of the Invention] As described above, according to the present invention,
When applying a rolling force to a roll pair that is in contact with the material to be continuously fed, even if the thickness of the material to be heated fluctuates even when the thickness of the material to be heated fluctuates by using a rolling means having compressibility with respect to the rolling force. Since the gap between the roll pairs is displaced according to the thickness variation, the variation in the rolling force can be made very small. Therefore,
It is possible to obtain a product having an extremely good shape without causing plastic deformation of the material to be heated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a pair of rolls and a pressing means in a first embodiment of the present invention.

FIG. 2 is a view showing a roll pair and a pressing means in a second embodiment.

FIG. 3 is a view showing a roll pair and a pressing means in a third embodiment.

FIG. 4 is a partially cutaway front view of the entire electric heating device in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Strip-shaped steel plate (material to be heated) 20, 30 Roll pair 21, 31 Holding roll 22, 32 Electricity roll 40 Rolling-down means 401 Pneumatic cylinder 405, 406 Solenoid valve 407 Switching control unit 408 Main control device 411 Compression coil spring 412 Motor 413 Screw down 60 AC power supply 70 Conductive member

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-128125 (JP, A) JP-A-52-103740 (JP, A) JP-B-34-9687 (JP, B1) JP-B-45- 7475 (JP, B1)

Claims (5)

(57) [Scope of request for utility model registration] At least one of a pair of rolls is brought into contact with a continuously fed strip-shaped steel sheet by a roll pair composed of an energized roll, and a rolling force is applied to the roll pair by a rolling-down means to electrically heat the strip-shaped steel sheet. In the current-carrying heating device, the reduction means has compressibility with respect to the reduction force,
An energization heating device, wherein the gap between the pair of rolls is configured to be displaceable in accordance with a change in the thickness of the strip-shaped steel plate, and the pair of rolls includes an energization roll and a pressing roll that is elastically deformable in a radial direction. 2. The electric heating apparatus according to claim 1, wherein said pressure reducing means is a gas cylinder. 3. The electric heating device according to claim 1, wherein said pressing means is a mechanical spring. 4. An electric heating apparatus according to claim 1, wherein said pressing means is a series combination of a gas cylinder and a mechanical spring. 5. The electric heating apparatus according to claim 1, wherein said pressure reducing means is a series combination of a liquid cylinder and a mechanical spring.