JP2013053367A - Metal strip stabilizer, method for manufacturing hot dipped metal strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal strip stabilizer with which loss in vibration suppression performance caused by an induced current between a vibration suppression coil and a position correction coil may be prevented.SOLUTION: The metal strip stabilizer includes: a non-contact displacement sensor which measures displacement of a metal strip 2 during online running; a control unit 5 which outputs a vibration suppression signal and a position correction signal after inputting a signal from the non-contact displacement sensor; a vibration suppression coil 7a which generates a magnetic force according to the vibration suppression signal output from the control unit 5; a position correction coil 7b which generates a magnetic force according to the position correction signal output from the control unit 5, a winding number thereof being larger than a winding number of the vibration suppression coil 7a; a core 6 where the vibration suppression coil 7a and the position correction coil 7b are wound concentrically, the magnetic force generated by the vibration suppression coil 7a and the position correction coil 7b being induced to the metal strip 2; and a counter induced current coil 13a which is disposed in series in an electric circuit supplying electricity to the position correction coil 7b.

Description

  The present invention relates to a metal strip stabilizer, a method of manufacturing a hot-dip metal strip using the same, and a metal strip manufactured using the same.

  In a metal band production line, keeping the metal band pass line stable by suppressing the vibration and warpage of the metal band not only improves the quality of the metal band, but also improves the efficiency of the production line. Also contributes.

  For example, in a production line for a hot-dip metal strip, there is a step of attaching the hot metal to the surface of the metal strip by passing the metal strip while being immersed in a molten metal bath. In this step, in order to suppress the occurrence of unevenness in the amount of adhesion of the molten metal, adjustment is performed to wipe off the excess molten metal adhering to the metal band by the wiping gas ejected from the gas wiper provided after the molten metal bath. .

  In the adjustment of the molten metal, it is necessary to eject the wiping gas from the gas wiper so that pressure is uniformly applied to the front and back of the metal strip in the plate width direction. Therefore, when the distance between the gas wiper and the metal band is not constant, such as when the metal band is vibrating, when the metal band is warped, or when the pass line of the metal band is biased to the front or back, The gas pressure is not uniform in the plate width direction and the plate passing direction. As a result, there arises a problem that uneven adhesion of the molten metal occurs in the front and back of the metal band, the plate width direction, and the sheet passing direction.

  As a method for solving such a problem, a technique is known that uses an electromagnet to suppress warpage and vibration of a metal band in a non-contact manner and stabilize the pass line of the metal band. For example, a pair of electromagnets are arranged so as to face each other with respect to a path line to which the metal band is to be moved, and the attraction force of each electromagnet is switched to each other according to a signal from a separately provided position detector. A method of making it act is known (see Patent Document 1).

  Responsiveness of the electromagnet is required to suppress the vibration of the metal band using the electromagnet as described above, and the attractive force of the electromagnet is required for warpage correction and pass line correction. Hereinafter, a combination of warp correction and pass line correction is referred to as position correction. In other words, in order to simultaneously realize vibration suppression and position correction of the metal band, contradictory properties of responsiveness and suction force are required. This is because if the number of turns of the coil is increased in order to increase the attractive force of the electromagnet, the responsiveness of the electromagnet is deteriorated. On the other hand, if the number of turns is decreased in order to improve the responsiveness of the electromagnet, the attractive force of the electromagnet is reduced. .

  In order to solve this problem, a metal band non-contact control technique using an electromagnet having two independent coils for vibration suppression and position correction has been proposed (see Patent Document 2). According to this technology, it is possible to perform vibration control with a vibration suppression coil with a small number of turns and to perform warp correction and pass line correction with a position correction coil with a large number of turns. Control can be performed in a compatible manner.

Japanese Patent Laid-Open No. 2-62355 JP 2004-124191 A

  However, in the metal band non-contact control technology using the electromagnet having two independent coils, the current change of the vibration suppression coil is corrected by the mutual induction between the vibration suppression coil and the position correction coil. On the contrary, a current change in the position correcting coil affects the current in the vibration suppressing coil. As a result, the control technique has a problem that it generates a suction force different from the suction force required by the control signal. In other words, the metal band stabilizer using the electromagnet having two independent coils for vibration suppression and position correction can control both vibration suppression capability and position correction capability, Due to the mutual induction between the vibration suppressing coil and the position correcting coil, there is a problem that the vibration suppressing ability is lowered.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide a metal strip that can avoid a decrease in vibration suppression capability due to an induced current between the vibration suppression coil and the position correction coil. It is to provide a stabilizer and a method for producing a hot-dip metal strip using the same.

  In order to solve the above-described problems and achieve the object, a metal strip stabilizer according to the present invention includes a non-contact displacement sensor that measures the displacement of a metal strip during online travel, and a signal from the non-contact displacement sensor. A controller that inputs and outputs a vibration suppression signal for suppressing the vibration of the metal band and a position correction signal for correcting the position of the metal band; and according to the vibration suppression signal output from the controller A first coil that generates a magnetic force, a second coil that generates a magnetic force in accordance with a position correction signal output from the control unit, and has a greater number of turns than the first coil, the first coil, and the first coil The two coils are concentrically wound, and are provided in series with a core that guides the magnetic force generated by the first coil and the second coil to the metal strip, and an electric circuit that feeds the second coil. With a third coil It is characterized in.

  According to the metal strip stabilizer and the hot-dip metal strip manufacturing method according to the present invention, it is possible to avoid a reduction in vibration suppression capability due to an induced current between the vibration suppression coil and the position correction coil.

FIG. 1 is a schematic diagram showing a configuration of a metal strip stabilizer according to an embodiment of the present invention. FIG. 2 is a schematic view showing an example of an electromagnet used in the metal strip stabilizer according to the embodiment of the present invention. FIG. 3 is a block diagram showing a configuration of a control unit in the metal strip stabilizer according to the embodiment of the present invention. FIG. 4 is a block diagram illustrating a configuration example of the operation amount calculation device. FIG. 5 is a schematic diagram showing an electric circuit of an electromagnet in the metal strip stabilizer according to the embodiment of the present invention. FIG. 6 is a schematic diagram showing a part of a general hot-dip metal strip production line. FIG. 7 is an enlarged view of the vicinity of a gas wiper in a hot-dip metal strip production line. FIG. 8 is a graph showing measurement data obtained by the metal strip stabilizer of the comparative example. FIG. 9 is a graph showing data measured by the metal strip stabilizer according to the embodiment of the present invention. FIG. 10 is a graph comparing the magnitudes of noise included in the measurement data shown in FIG. 8 and the measurement data shown in FIG.

  A metal strip stabilizer according to an embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing the configuration of a metal strip stabilizer 1 according to an embodiment of the present invention. As shown in FIG. 1, a metal band stabilizer 1 according to an embodiment of the present invention includes a pair of electromagnets 3a, which are installed facing each other so as to sandwich a metal band 2 traveling in the direction of arrow A in the figure. 3b, a non-contact displacement sensor 4 disposed in the vicinity of the electromagnets 3a and 3b, and a controller 5 that controls the electromagnets 3a and 3b based on an input from the non-contact displacement sensor 4.

  FIG. 2 is a schematic view showing an example of an electromagnet 3a used in the metal strip stabilizer 1 according to the embodiment of the present invention. Here, only the electromagnet 3a for the surface of the metal band 2 will be described. However, the following description also applies to the electromagnet 3b for the back surface of the metal band 2. The electromagnet 3a shown in FIG. 2 is configured by a concentric coil including a coil 7a and a coil 7b configured by concentrically winding two windings around one core 6. The two coils 7a and 7b are configured by changing the number of turns, and the coil with the smaller number of turns of the two coils 7a and 7b is the vibration suppressing coil 7a, and the coil with the larger number of turns is the position correction. Coil 7b.

  The vibration suppression coil 7a is required to have a high response enough to sufficiently follow the vibration frequency of the target metal band 2 (usually the natural frequency such as bending or twisting of the metal band). A large suction force is not required to suppress the vibration. Therefore, the number of turns of the vibration suppressing coil 7a is smaller than that of the position correcting coil 7b.

  On the other hand, the position correction coil 7b does not require high responsiveness, but it is desirable that it can generate a large suction force with a small current. Therefore, it is preferable that the number of turns of the position correcting coil 7b is large as long as the size of the electromagnet 3a and the value of the electric resistance do not become too large.

  Below, the relationship between the number of turns of a coil, the responsiveness of an electromagnet, and attractive force is demonstrated.

The operation of the electromagnet is expressed by the equation (1).
e = Ldi / dt + Ri (1)
Here, e is an applied voltage, i is a current flowing through the coil, L is an inductance of the coil, and R is a resistance of the coil.

As shown in Expression (1), the current i flowing through the coil is a first-order lag system with respect to the applied voltage e, and its time constant T is expressed by Expression (2).
T = L / R (2)
Here, the inductance L of the coil is proportional to the square of the number of turns N of the coil, and the resistance R of the coil is proportional to the number N of turns of the coil. Therefore, the time constant T is proportional to the number of turns N of the coil according to the equation (2). This means that as the number of turns of the coil increases, the time constant increases and the quick response decreases.

On the other hand, the attractive force F of the electromagnet is proportional to the square of the number of turns N of the coil and the square of the current i flowing through the coil, as represented by the equation (3).
F Ｎ N ² i ² (3)
Therefore, in order to obtain a large attractive force with the same current, it is advantageous to increase the number of turns N of the coil.

  In summary, it can be seen that the number of turns N of the coil is preferably small in order to increase the response, but is large in order to increase the attractive force. Therefore, in the electromagnet 3a according to the embodiment of the present invention, the number of turns of the vibration suppressing coil 7a that does not require a large attractive force but requires high responsiveness is configured to be smaller than the number of turns of the position correcting coil 7b. . On the other hand, the number of turns of the position correcting coil 7b which requires high responsiveness but does not require high responsiveness is configured to be larger than the number of turns of the vibration suppressing coil 7a.

  FIG. 3 is a block diagram showing a configuration of the control unit 5 in the metal strip stabilizer 1 according to the embodiment of the present invention. As shown in FIG. 3, the control unit 5 of the metal band stabilizer 1 according to the embodiment of the present invention includes an operation amount calculation device 8, front and back distribution devices 9a and 9b, amplifiers 10a, 10b, 10c, and 10d. And inductors 11a and 11b.

  The operation amount calculation device 8 performs so-called PID control such as proportionality, differentiation, and integration on the deviation signal between the measured value of the displacement of the metal strip by the non-contact displacement sensor 4 and the target value set by the input means 12. The vibration suppression signal and the position correction signal are output. FIG. 4 is a block diagram illustrating a configuration example of the operation amount calculation device 8.

  As shown in FIG. 4, the operation amount calculation device 8 includes a PID control unit 8 a for suppressing vibration and a PID control unit 8 b for position correction. The vibration suppression PID control unit 8a is a calculation unit that inputs a deviation signal between the measured value of the displacement of the metal band and the target value and outputs a vibration suppression signal. The position correction PID control unit 8b is a metal This is a calculation means for inputting a deviation signal between the measured value of the band displacement and the target value and outputting a position correction signal.

  Here, the calculation of the PID control unit 8a for suppressing vibration is a calculation that places importance on responsiveness, and the calculation of the PID control unit 8b for position correction is a calculation that puts importance on static suction force. That is, the calculation of the vibration suppression PID control unit 8a is set so that the gain of the high frequency component included in the input signal is increased, and the calculation of the position correction PID control unit 8b is the low frequency component included in the input signal. The gain of the component is set to be large. For example, the setting is realized by increasing the setting of the differential gain in the PID control unit 8a for vibration suppression and increasing the setting of the integral gain in the PID control unit 8b for position correction.

  Here, the high frequency and the low frequency mean the height in comparison between the PID control unit 8a for vibration suppression and the PID control unit 8b for position correction. Further, according to the above configuration, the vibration suppression signal is a signal including a lot of high frequency components, and the position correction signal is a signal including a lot of low frequency components. This is because the average value of the frequency components of the vibration suppression signal is the position. This means that it is higher than the average value of the frequency components of the correction signal, and it is allowed that an overlapping portion exists between the frequency distribution of the vibration suppression signal and the frequency distribution of the position correction signal.

  By configuring the operation amount calculation device 8 as described above, the operation amount calculation device 8 includes a component used for vibration suppression and a component used for position correction from the measured value of the displacement of the metal strip by the non-contact displacement sensor 4. Are separated, and the vibration suppression signal and the position correction signal are transmitted to the vibration suppression front / back distribution device 9a and the position correction front / back distribution device 9b, respectively.

  Returning to FIG. The front / back distribution devices 9a and 9b distribute the vibration suppression signal and the position correction signal calculated by the operation amount calculation device 8 for use in the electromagnet 3a for the surface of the metal band 2 and the electromagnet 3b for the back surface. The amplifier 10a supplies power to the vibration suppression coil of the electromagnet 3a according to the surface vibration suppression signal distributed by the front / back distribution device 9a, and the amplifier 10b follows the surface position correction signal distributed by the front / back distribution device 9b. The power is supplied to the position correcting coil of the electromagnet 3a. On the other hand, the amplifier 10c supplies power to the vibration suppression coil of the electromagnet 3b in accordance with the vibration suppression signal for the back surface distributed by the front / back distribution device 9a, and the amplifier 10d corrects the position for the back surface distributed by the front / back distribution device 9b. In accordance with the signal, power is supplied to the position correction coil of the electromagnet 3b.

  FIG. 5 is a schematic diagram showing an electric circuit of the electromagnet 3a in the metal strip stabilizer 1 according to the embodiment of the present invention. Here, for the sake of space, only the electric circuit for the electromagnet 3a for the surface of the metal band 2 is schematically shown.

  As shown in FIG. 5, a vibration suppression amplifier 10a and a position correction amplifier 10b are connected to the vibration suppression coil 7a and the position correction coil 7b, respectively. The vibration suppression amplifier 10a supplies power to the vibration suppression coil 7a through an electric circuit in accordance with the input vibration suppression signal. The position correction amplifier 10b supplies power to the position correction coil 7b through an electric circuit in accordance with the input position correction signal.

  Further, the electric circuit including the position correcting coil 7b and the position correcting amplifier 10b includes a coil 13a in series as the inductor 11a. Hereinafter, this is referred to as an induction current countermeasure coil 13a. In the example of the induced current countermeasure coil 13a shown in FIG. 5, an example of a coil in which the magnetic circuit 13b is configured as a closed circuit is illustrated. A coil in which the magnetic circuit 13b is a closed circuit is also called a toroidal coil. Although the magnetic circuit 13b of the induction current countermeasure coil 13a can obtain an effect even when the circuit is open, the magnetic circuit 13b of the induction current countermeasure coil 13a is closed so as not to be affected by environmental changes due to magnetic flux leakage or the like. It is desirable to configure as

  The induction current countermeasure coil 13a configured as described above operates as follows in the metal strip stabilizer 1 according to the embodiment of the present invention.

  A high frequency current flows through the vibration suppressing coil 7a in accordance with the vibration frequency of the metal band 2. Since the vibration suppressing coil 7a and the position correcting coil 7b are configured as concentric coils, a high frequency electromotive force is generated in the position correcting coil 7b by mutual induction.

  In the metal band stabilizer of the prior art, the current of the position correcting coil 7b fluctuates due to the electromotive force of mutual induction, and the attraction force of the position correcting coil 7b fluctuates, adversely affecting vibration control. However, in the metal band stabilizer 1 according to the embodiment of the present invention, since the induction current countermeasure coil 13a is connected to the electric circuit of the position correction coil 7b, the position correction is performed by the inductance of the induction current countermeasure coil 13a. The current change of the electric circuit of the coil 7b can be suppressed. Hereinafter, a mechanism for suppressing the current fluctuation of the electric circuit of the position correction coil 7b by the induced current countermeasure coil 13a will be described.

When the current flowing through the vibration suppression coil 7a is i ₁ and the current flowing through the position correction coil 7b is i ₂ , the induced electromotive force e ₁ generated in the vibration suppression coil 7a and the position correction coil 7b are generated. induced electromotive force e ₂ which is expressed by the following equation.

e ₁ = −Mdi ₂ / dt (4)
e ₂ = −Mdi ₁ / dt (5)
Here, M is a mutual inductance between the vibration suppressing coil 7a and the position correcting coil 7b, and is expressed by the following equation.
M = k × √ (L ₁ × L ₂ ) (6)
Here, k is a coefficient determined by the shape and mutual position of the coil, L ₁ is the inductance of the vibration suppression coil 7a, L ₂ is the inductance of the position correction coil 7b.

A static current for performing position correction flows through the position correction coil 7b, and the time change di ₂ / dt of the current becomes substantially zero. Therefore, as can be seen from the above equation (4), the induced electromotive force e ₁ is hardly generated in the vibration suppressing coil 7a. That is, the current for position correction flowing through the position correction coil 7b hardly affects the vibration suppression control by the vibration suppression coil 7a.

On the other hand, a dynamic current for suppressing vibration flows through the vibration suppressing coil 7a, and the time change di ₁ / dt of the current is large. Therefore, as can be seen from the above equation (5), a large induced electromotive force e ₂ is generated in the position correcting coil 7b.

  However, in the metal band stabilizer 1 according to the embodiment of the present invention, since the induction current countermeasure coil 13a is connected to the electric circuit of the position correction coil 7b, the current generated by the induced electromotive force is not corrected. This is suppressed by the combined inductance of the coil 7b and the induction current countermeasure coil 13a.

As described with reference to FIG. 5, since the position correcting coil 7b and the induced current countermeasure coil 13a are connected in series, the combined inductance L of the position correcting coil 7b and the induced current countermeasure coil 13a. Is expressed by the following equation.
L = L ₂ + L ₃ (7)
Here, L _{2 and} L ₃ are the inductances of the position correction coil 7b and the induction current countermeasure coil 13a, respectively.

By the way, the reactance of the alternating current flowing through the coil is proportional to the frequency and inductance of the alternating current. On the other hand, as described above, the vibration suppression signal is a signal containing a lot of high frequency components, and the position correction signal is a signal containing a lot of low frequency components. Therefore, the current induced from the vibration suppressing coil 7a to the position correcting coil 7b is a current containing a large amount of high frequency components, and is greatly affected by the magnitude of the combined inductance L and suppressed. On the other hand, the current flowing through the position correcting coil 7b is not greatly affected by the magnitude of the combined inductance L. Moreover, as can be seen from equation (7), the counter induced current coil 13a is also connected as a combined inductance L is increased, so it does not change the magnitude of the inductance L ₂ of the position correction coil 7b, the position correction The characteristics as an electromagnet by the coil 7b for use are not changed.

  The operation of the electromagnet is a first-order lag system as described above, and its time constant is given by equation (2). Therefore, the larger the combined inductance L, the larger the time constant, and the current fluctuation can be suppressed. On the other hand, the combined inductance L can be increased by increasing the number of turns of the induction current countermeasure coil 13a. However, when the number of turns is large, the size of the induction current countermeasure coil 13a is increased and a large installation space is required. At the same time, since the resistance of the entire circuit is increased, there is a demerit that the load on the amplifier is increased.

Therefore, it is necessary to determine the inductance of the coil for countermeasure against induced current in consideration of the vibration control performance and the above disadvantages. According to the verification experiment of the effect of the embodiment of the present invention to be described later, the time constant of the serial combination of the position correction coil 7b and the induction current countermeasure coil 13a is 4 to 10 times that of the position correction coil 7b. It is preferable to be within the range. If this condition is re-expressed from the relationship of the expression (2), the metal strip stabilizer 1 according to the embodiment of the present invention includes the vibration suppression coil 7a, the position correction coil 7b, and the current countermeasure coil 13a. It is preferably designed to be in the range of the formula.
_{4L 2 / R 2 <(L} 2 + L 3) / (R 2 + R 3) <10L 2 / R 2 ··· (8)
Here, L ₂ and L ₃ are inductances of the position correction coil 7b and the induction current countermeasure coil 13a, respectively, and R ₂ and R ₃ are resistances of the position correction coil 7b and the induction current countermeasure coil 13a, respectively. It is.

  The provision of the induction current countermeasure coil 13a intentionally deteriorates the responsiveness of the position correcting coil 7b. However, as described above, since the responsiveness is not required for the position correction coil 7b, the position correction of the metal strip is not affected. As a result, the mutual induction current between the vibration suppressing coil 7a and the position correcting coil 7b is suppressed to avoid an adverse effect on vibration control, and the response of the vibration suppressing coil 7a and the attractive force of the position correcting coil 7b are increased. It is possible to achieve both.

  Next, the structural example which arrange | positions the metal strip stabilizer 1 which concerns on embodiment of this invention in the production line of a hot dipped metal strip is demonstrated.

  FIG. 6 is a schematic diagram showing a part of a general hot-dip metal strip production line. In the production line for the hot-dip metal strip shown in FIG. 6, the metal strip 2 is transported from a previous process such as a cold rolling process, and is subjected to annealing treatment in an annealing furnace 14 maintained in a non-oxidizing or reducing atmosphere. Then, the molten metal is cooled to approximately the same temperature as the molten metal and guided into the molten metal bath 15.

  In the molten metal bath 15, the metal strip 2 is passed through while being immersed in the molten metal, and the molten metal adheres to the surface thereof. Thereafter, the metal strip 2 drawn out from the molten metal bath 15 is wiped with excess molten metal by the gas ejected from the gas wiper 16, and the amount of adhesion of the molten metal is adjusted.

  In the subsequent process, depending on the application, for example, when the metal strip 2 is used as an automobile outer plate, the alloying treatment is performed using the alloying furnace 17 to reheat the metal strip to produce a homogeneous alloy layer. May be applied. After passing through the cooling zone 18, the metal strip 2 is subjected to special rust prevention and corrosion resistance treatment in the chemical conversion treatment section 19, wound around a coil and shipped.

  FIG. 7 is an enlarged view of the vicinity of the gas wiper (dashed line region in FIG. 6) in the hot-dip metal strip production line. As shown in FIG. 7, in the vicinity of the gas wiper 16 in the production line of the hot dip metal strip, the drawing roller 20 pulls the metal strip 2 into the molten metal bath 15, and the molten metal into the metal strip 2 in the molten metal bath 15. The pulling roller 21 pulls the metal strip 2 out of the molten metal bath 15. The gas wiper 16 is disposed on a pass line in the middle of the pulling roller 21 pulling up the metal band 2, and adjusts the amount of molten metal attached by wiping off excess molten metal adhering to the metal band 2.

  The electromagnets 3a and 3b and the non-contact displacement sensor 4 of the metal band stabilizer 1 according to the embodiment of the present invention are arranged in a pass line immediately above the gas wiper 16 to control the vibration and position of the metal band. With this arrangement, the distance between the gas wiper 16 and the metal strip 2 becomes constant, so that the pressure of the wiping gas becomes uniform and unevenness in the amount of molten metal attached to the metal strip 2 can be suppressed.

  Finally, a verification experiment of the effect of the metal strip stabilizer 1 according to the embodiment of the present invention will be described. FIG. 8 is a graph showing measurement data obtained by the metal strip stabilizer of the comparative example, and FIG. 9 is a graph showing measurement data obtained by the metal strip stabilizer 1 according to the embodiment of the present invention. FIG. 10 is a graph comparing the magnitudes of noise included in the measurement data shown in FIG. 8 and the measurement data shown in FIG.

  The graph shown in FIG. 8 shows that in a metal band stabilizer that does not use the induction current countermeasure coil 13a, a vibration control command with a current of 3A and a frequency of 10Hz is given to the vibration suppression coil 7a, and a current of 0A is supplied to the position correction coil 7b. The current actual value when a constant current control command is given is plotted. Note that the current value of the vibration control command is also described in the graph shown in FIG.

  As can be understood from the graph shown in FIG. 8, in the comparative example, a constant current of 0 A should flow through the position correction coil 7b, but the current has been detected as the actual value. The current flowing through the position correction coil 7b is an induced current in which fluctuations in the vibration control current flowing through the vibration suppression coil 7a are generated on the position correction coil 7b side due to electromagnetic induction. Furthermore, according to the graph shown in FIG. 8, when the induced current flowing through the position correcting coil 7b fluctuates, the induced current also flows through the vibration suppressing coil 7a, and there is a disturbance in the current results of vibration control. It has occurred.

  The graph shown in FIG. 9 shows that in the metal band stabilizer 1 according to the embodiment of the present invention, a vibration control command having a current of 3 A and a frequency of 10 Hz is given to the vibration suppression coil 7 a and a current 0 A is supplied to the position correction coil 7 b. This is a plot of actual current values when a constant current control command is given. The inductance of the induction current countermeasure coil 13a in this verification experiment is designed so that the time constant of the series combination of the position correction coil 7b and the induction current countermeasure coil 13a is five times that of the position correction coil 7b. Has been.

  As can be understood from the graph shown in FIG. 9, the vibration suppressing coil 7 a and the position correcting coil 7 b according to the embodiment of the present invention are hardly affected by the induced current, and control that accurately follows the control command is performed. It has been realized. Further, as can be seen by comparing the graphs shown in FIG. 8 and FIG. 9, in the vibration suppressing coil 7a and the position correcting coil 7b in the comparative example, fluctuations in the induced current induced in the position correcting coil 7b further vibrate. Although a vicious circle that affects the suppression coil 7a has occurred, the vicious circle does not occur in the vibration suppression coil 7a and the position correction coil 7b according to the embodiment of the present invention. Further, as can be understood from the graph shown in FIG. 10, according to the metal strip stabilizer 1 according to the embodiment of the present invention, the induced current that hinders vibration control can be reduced to 1/11 times. is there. That is, the metal strip stabilizer 1 according to the embodiment of the present invention can avoid a decrease in vibration suppression capability due to an induced current between the vibration suppression coil and the position correction coil.

  As described above, the metal strip stabilizer 1 according to the embodiment of the present invention inputs the non-contact displacement sensor 4 that measures the displacement of the metal strip 2 during online travel, and the signal from the non-contact displacement sensor 4, A control unit 5 that outputs a vibration suppression signal for suppressing the vibration of the metal band 2 and a position correction signal for correcting the position of the metal band 2, and generates a magnetic force according to the vibration suppression signal output from the control unit 5 The vibration suppression coil 7a, the position correction coil 7b having a larger number of turns than the vibration suppression coil 7a, which generates a magnetic force in accordance with the position correction signal output from the control unit 5, and the vibration suppression coil 7a and the position correction coil The coil 7b is concentrically wound, and is provided in series with a core 6 that guides the magnetic force generated by the vibration suppressing coil 7a and the position correcting coil 7b to the metal band 2, and an electric circuit that supplies power to the position correcting coil 7b. Invitation Because and a current protection coils 13a, it is possible to avoid a decrease in the vibration suppression ability by induced current between the position correction coil 7b and the vibration suppression coil 7a.

  Here, the control unit 5 of the metal band stabilizer 1 according to the embodiment of the present invention has a higher frequency component than the position correction signal with respect to the deviation signal between the signal input from the non-contact displacement sensor 4 and the target value. Since the vibration suppression signal is output by calculating to increase the gain of the position, and the position correction signal is output by calculating to increase the gain of the low frequency component than the vibration suppression signal. An appropriate signal used for vibration suppression and an appropriate signal used for position correction can be distributed from the displacement amount thus determined. In addition, the control unit 5 of the metal strip stabilizer 1 according to the embodiment of the present invention has a differential gain that is higher than that of the position correction signal with respect to the deviation signal between the signal input from the non-contact displacement sensor 4 and the target value. It is preferable to output a vibration suppression signal by performing a PID control calculation with a larger setting, and to output a position correction signal by performing a PID control calculation with a larger integral gain setting than the vibration suppression signal.

In addition, the time constant of serial combination of the position correction coil 7b and the induced current countermeasure coil 13a of the metal strip stabilizer 1 according to the embodiment of the present invention is in the range of 4 to 10 times that of the position correction coil 7b. It is preferably designed to be within. Alternatively, the position correcting coil 7b and the induced current countermeasure coil 13a of the metal strip stabilizer 1 according to the embodiment of the present invention preferably satisfy the following formula.
4L ₂ / R ₂ <(L ₂ + L ₃ ) / (R ₂ + R ₃ ) <10L ₂ / R ₂
Here, L ₂ and L ₃ are inductances of the position correction coil 7b and the induction current countermeasure coil 13a, respectively, and R ₂ and R ₃ are resistances of the position correction coil 7b and the induction current countermeasure coil 13a, respectively. It is.

  In addition, the metal band stabilizer 1 according to the embodiment of the present invention includes a vibration suppression coil 7a, a position correction coil 7b, and a core 6 on the front and back surfaces of the metal band 2 and a vibration suppression coil for the surface. 7a, the position correcting coil 7b, and the core 6, and the back surface vibration suppressing coil 7a, the position correcting coil 7b, and the core 6 are provided to the front side and the back side of the metal strip 2, respectively. Vibration and displacement can be suppressed.

  The control unit 5 of the metal band stabilizer 1 according to the embodiment of the present invention inputs a signal from the non-contact displacement sensor 4 and controls the vibration suppression signal for suppressing the vibration of the metal band 2 and the metal band 2. An operation amount calculation device 8 that outputs a position correction signal for correcting the position, and a vibration suppression signal that is output from the operation amount calculation device 8 includes a vibration suppression coil 7a for the front surface and a vibration suppression coil 7a for the rear surface. A front / back distribution device 9b that distributes the position correction signal output from the manipulated variable calculation device 8 to the front-side position correction coil 7b and the back-side position correction coil 7b; According to the vibration suppression signal for the surface distributed by the front / back distribution device 9a, the amplifier 10a for supplying power to the vibration suppression coil 7a for the surface and the position correction signal for the surface distributed by the front / back distribution device 9b position In accordance with the back side vibration suppression signal distributed by the front / back distribution device 9a, the amplifier 10c for supplying power to the back side vibration suppression coil 7a, and the front / back distribution device 9b An amplifier 10d for supplying power to the back surface position correction coil 7b according to the back surface position correction signal, and the induced current countermeasure coil 13a is provided between the amplifier 10b and the front surface position correction coil 7b; and Since it is provided in each of the electric circuits between the amplifier 10d and the position correcting coil 7b for the back surface, it is possible to suppress the vibration and displacement of the metal band 2 toward the front surface side and the back surface side.

  Further, in the metal band stabilizer 1 according to the embodiment of the present invention, the magnetic circuit 13b of the induction current countermeasure coil 13a is configured as a closed circuit, so that it is less susceptible to environmental changes due to magnetic flux leakage or the like.

  Furthermore, the manufacturing method of the hot dip metal strip which concerns on embodiment of this invention wipes off the excess molten metal adhering to the adhesion process which makes a molten metal adhere to the metal strip 2 in a production line through-plate, and the metal strip 2 Since there is an adjustment process for adjusting the amount of molten metal deposited by the gas wiper 16 and a control process for controlling the vibration and position of the metal band 2 in a non-contact manner by the metal band stabilizer 1, the pressure of the wiping gas is uniform. Thus, unevenness in the amount of molten metal attached to the metal strip 2 can be suppressed.

  Moreover, since the metal strip which concerns on embodiment of this invention is manufactured with the said manufacturing method, it can suppress the nonuniformity of the adhesion amount of a molten metal.

  As mentioned above, although this invention was demonstrated based on embodiment, in implementation of this invention, this invention is not limited with the description and drawing which make a part of indication of this invention by this embodiment.

  The present invention is useful for a line for producing a metal strip, and is particularly suitable for a production line for a hot dipped metal strip.

DESCRIPTION OF SYMBOLS 1 Metal band stabilizer 2 Metal band 3a, 3b Electromagnet 4 Non-contact displacement sensor 5 Control part 6 Core 7a Vibration suppression coil 7b Position correction coil 8 Manipulation unit 9a, 9b Front / back distribution apparatus 10a-d Amplifier 11a, DESCRIPTION OF SYMBOLS 11b Inductor 12 Input means 13a Inductive current countermeasure coil 13b Magnetic circuit 14 Annealing furnace 15 Molten metal bath 16 Gas wiper 17 Alloying furnace 18 Cooling zone 19 Chemical conversion part 20 Pull-in roller 21 Pull-up roller

The present invention relates to a stabilizer, and a manufacturing how the molten plating metal strip using the same metal strip.

Claims (8)

A non-contact displacement sensor that measures the displacement of the metal strip running online;
A controller that inputs a signal from the non-contact displacement sensor and outputs a vibration suppression signal for suppressing vibration of the metal strip and a position correction signal for correcting the position of the metal strip;
A first coil that generates a magnetic force in accordance with a vibration suppression signal output from the control unit;
A second coil having a larger number of turns than the first coil, which generates a magnetic force in accordance with a position correction signal output from the control unit;
A core for concentrically winding the first coil and the second coil, and guiding the magnetic force generated by the first coil and the second coil to the metal strip;
A third coil provided in series with an electric circuit for supplying power to the second coil;
A metal strip stabilizer characterized by comprising:   The control unit performs an operation such that a gain of a high frequency component is larger than that of the position correction signal, with respect to a deviation signal between a signal input from the non-contact displacement sensor and a target value, and thereby the vibration suppression signal. The metal band stabilizer according to claim 1, wherein the position correction signal is output by performing an operation such that a gain of a low frequency component is larger than that of the vibration suppression signal. .   The control unit performs a PID control calculation in which a differential gain is set larger than the position correction signal with respect to a deviation signal between a signal input from the non-contact displacement sensor and a target value, thereby the vibration suppression signal. The position correction signal is output by performing a PID control calculation in which an integral gain is set larger than that of the vibration suppression signal, and the metal band stability according to claim 1 or 2, apparatus.   The time constant of serial combination of the second coil and the third coil is designed to be within a range of 4 to 10 times the time constant of the second coil. Item 4. The metal band stabilizer according to any one of Items 1 to 3. The metal strip stabilizer according to any one of claims 1 to 4, wherein the second coil and the third coil satisfy the following expression.
4L ₂ / R ₂ <(L ₂ + L ₃ ) / (R ₂ + R ₃ ) <10L ₂ / R ₂
Here, L ₂ and L ₃ are inductances of the second coil and the third coil, respectively, and R ₂ and R ₃ are resistances of the second coil and the third coil, respectively. .   The metal strip stabilizer according to any one of claims 1 to 5, wherein the magnetic circuit of the third coil is configured as a closed circuit. An adhesion process for adhering molten metal to a metal strip in the production line through plate,
An adjustment step of adjusting the amount of adhesion of the molten metal by a gas wiper that wipes off the excess molten metal adhering to the metal band;
A control process for controlling the vibration and position of the metal band in a non-contact manner by the metal band stabilizer according to any one of claims 1 to 6,
A method for producing a hot dipped metal strip, comprising:   A metal strip manufactured by the manufacturing method according to claim 7.

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