JP4862471B2 - Bath roll speed detecting device, bath roll speed control method and apparatus - Google Patents

Description

  The present invention relates to an apparatus for detecting the rotational speed of a roll in bath, a method for controlling the rotational speed of a roll in bath, and an apparatus therefor.

2. Description of the Related Art Conventionally, as an invention provided with a means for measuring the rotation speed of a roll in bath, for example, a drive structure 40 for a roll in a bath for hot dipping shown in FIG. 7 is known (see Patent Document 1).
7 includes a power source device (not shown) for supplying a variable frequency power source to the stator 41, and a detecting means 44 for detecting the rotational speed of the in-bath roll 43. A control circuit (not shown) is provided that issues a frequency instruction signal to the power supply device after comparing the set rotational speed with the rotational speed detected by the detecting means 44. Further, the detection means 44 is mounted on the support frame 46 and adopts a configuration for picking up rotation of the detected body 48 provided in a part of the shaft portion 47.

Then, according to the hot-plating bath roll drive structure 40, the bath roll 43 can be controlled to a preferred rotational speed appropriately corresponding to the speed of the material 49 to be plated.
JP 2001-295013 A

However, in the hot-roll bath driving structure 40, the detection means 44 is mounted on the support frame 46, so that the detection means 44 is immersed in a high-temperature bath. There is a problem that the lifetime is shortened.
The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a roll rotation speed detecting device in the bath that has a long product life and can accurately measure the rotation speed of the roll in the bath. It is to provide.
Another object of the present invention is to accurately measure the rotational speed of the roll in the bath and prevent slippage between the roll in the bath and the steel strip based on the measured rotational speed, thereby improving the quality of the plated steel strip. An object of the present invention is to provide a method and apparatus for controlling the rotational speed of a roll in a bath that can be improved.

The bath roll rotation speed detection device according to claim 1 of the present invention is a bath roll rotation speed detection device that detects the rotation speed of a non-driven bath roll immersed in a metal bath for hot dipping. There,
A permanent magnet provided in the bath roll;
A detection sensor is provided outside the metal bath and detects a magnetic flux of the permanent magnet.
In the bath roll rotation speed detecting device according to claim 2 of the present invention, the bath roll rotation speed detecting device according to claim 1, wherein the permanent magnets are equally spaced in the circumferential direction of the bath roll. Four or more are provided.

In addition, the method for controlling the rotation speed of the roll in bath according to claim 3 of the present invention is a bath that controls the rotation speed of the roll in the non-drive type bath that is immersed in a metal bath for hot dipping and supports a steel strip. A method for controlling the rotation speed of the middle roll,
Detecting the magnetic flux of the permanent magnet provided in the roll in the bath by a detection sensor provided outside the bath of the metal bath;
Calculating the rotation speed of the roll in the bath based on the detected magnetic flux;
And a step of adjusting a pushing amount of the roll in the bath with respect to the steel strip based on the calculated rotation speed and a preset transport speed of the steel strip.

Furthermore, the roll speed control device for a roll in a bath according to claim 4 of the present invention is a bath that controls the rotation speed of a non-drive-type roll in a bath that is immersed in a metal bath for hot dipping and supports a steel strip. A rotation speed control device for the middle roll,
A permanent magnet provided in the bath roll;
A detection sensor that is provided outside the metal bath and detects the magnetic flux of the permanent magnet;
Based on the detected magnetic flux, a rotational speed calculating means for calculating the rotational speed of the roll in the bath,
A pressing amount control means for adjusting a pressing amount of the roll in the bath against the steel strip based on the calculated rotation speed and a preset transport speed of the steel strip; To do.

According to the in-bath roll rotation speed detecting device according to claim 1 or 2, the permanent magnet provided in the bath-in-roll, the detection sensor provided outside the bath of the metal bath, and detecting the magnetic flux of the permanent magnet; With this configuration, the product life of the detection sensor can be extended, and the rotational speed of the roll in the bath can be accurately measured.
According to the method for controlling the rotational speed of the roll in bath or the rotational speed control apparatus for the roll in bath according to claim 3 or 4 of the present application, the magnetic flux of the permanent magnet provided in the roll in the bath is used outside the bath of the metal bath. A step of detecting by the detection sensor provided in the step, a step of calculating the rotational speed of the roll in the bath based on the detected magnetic flux, the calculated rotational speed, and conveyance of the preset steel strip And a step of adjusting the pushing amount of the roll in the bath with respect to the steel strip based on the speed, it becomes possible to prevent a slip generated between the roll in the bath and the steel strip, It is possible to improve the quality of the plated steel strip.

Hereinafter, an in-bath roll rotation speed detection device according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a continuous hot dip galvanizing line. FIG. 2 is a front view of the in-bath roll rotation speed control device according to the first embodiment of the present invention. FIG. 3 is a side view of the in-bath roll rotation speed control device. FIG. 4 is a side view of the magnet ring. FIG. 5 is a configuration diagram of the magnetic sensor.

The in-bath roll rotation speed control device 1 according to the first embodiment of the present invention is provided in a continuous molten metal plating line for continuously plating a steel strip S formed in a long shape, which is continuously conveyed. In this embodiment, the case where the roll rotation speed control device 1 in the bath is applied to the continuous hot dip galvanizing line 2 will be described as an example.
The continuous hot dip galvanizing line 2 performs galvanizing treatment on the steel strip S that has undergone the cold rolling process, the washing process, and the annealing process, and as shown in FIG. A sink roll 4 and two sets of guide rolls 5 are provided.

The zinc bath 3 stores molten zinc Z that has been heated and melted, and allows the molten zinc Z to adhere to the surface of the steel strip S by allowing the steel strip S to pass through the molten zinc Z.
The sink roll 4 is rotatably supported by a bearing (not shown) in the zinc bath 3, and the direction of the steel strip S led into the zinc bath 3 is changed to the outlet side of the zinc bath 3. Is what you do.

Each guide roll 5 is rotatably supported by a bearing 7 in the zinc bath 3 and supports the steel strip S whose direction has been changed by the sink roll 4. And both guide rolls 5 are installed one by one on the front side and the back side of the steel strip S to be conveyed with the same direction as the sink roll 4 and the axis extending.
Here, the sink roll 4 and the guide roll 5 are formed in a non-driving type.

And the roll speed control apparatus 1 in the bath which concerns on this invention is provided in this continuous hot-dip galvanization line 2, and as shown in FIG.2 and FIG.3, the roll speed detection means 10 in a bath, and slip determination means 11, an alarm unit 12, and a roll push-in amount adjusting unit 13 in the bath.
The in-bath roll rotation speed detection means 10 includes a permanent magnet 14 provided in the guide roll 5, a magnetic sensor (detection means) 15 provided outside the zinc bath 3, and an amplifier 16 that amplifies a signal from the magnetic sensor 15. And a rotation speed calculation means 17 for calculating the rotation speed of the roll in the bath.

  Four permanent magnets 14 are installed at equal intervals in the circumferential direction of the guide roll 5 at the longitudinal ends of the guide roll 5. In this case, the permanent magnet 14 is installed on the guide roll 5 in the present embodiment, as shown in FIG. 4, by forming a magnet ring 18 in which four permanent magnets 14 are installed at equal intervals in the circumferential direction. The magnet ring 18 is fitted and fixed to the shaft portion 19 of the guide roll 5. The permanent magnet 14 may be installed on the guide roll 5 by directly installing the permanent magnet 14 at the longitudinal end of the guide roll 5. Further, the number of permanent magnets 14 provided in the guide roll 5 can be set as appropriate in one or more, but in order to detect the change in the rotational speed of the guide roll 5 during one rotation of the guide roll 5 with high accuracy, The guide roll 5 is preferably provided with four or more permanent magnets 14. And by setting it as the structure provided with two or more permanent magnets 14 in the guide roll 5, it becomes possible to calculate the rotational speed of the guide roll 5 between each permanent magnet 14, and each time the guide roll 5 rotates 1 time. It is also possible to calculate the variation in the rotational speed between the permanent magnets 14.

Here, in the present embodiment, the permanent magnet 14 employs a configuration provided in only one of the both guide rolls 5, but may be configured in both the guide rolls 5. It does not matter as a structure provided.
The magnetic sensor 15 is provided so as to be able to detect the magnetic flux H of each permanent magnet 14 outside the zinc bath 3. In addition, the configuration in which the magnetic sensor 15 is provided outside the bath of the zinc bath 3 can extend the product life of the magnetic sensor 15. Here, as shown in FIG. 5, the magnetic sensor 15 is configured as a flux gate system including two high permeability cores 21, an excitation coil 22 and a detection coil 23 wound around the high permeability core 21. Has been.

When the rotational speed of the guide roll 5 is measured by the bath roll speed detecting means 10, an alternating current flux is generated by applying an alternating current from the transmitter 24 to the exciting coil 22, thereby magnetically saturating the exciting coil 22. Leave it in a state. In this state, when the magnetic flux H of the permanent magnet 14 is applied as an external magnetic flux to the high permeability core 21, an induced voltage is generated in the detection coil 23 due to the magnetic characteristics of the high permeability core 21. Here, the magnetic flux detected by the high permeability core 21 is in a state in which the geomagnetism B ₀ is added to the magnetic flux H of the permanent magnet 14, and therefore the induced voltage output from the detection coil 23 is the geomagnetism B ₀ . This is the sum of the induced voltage based on the induced voltage and the induced voltage based on the magnetic flux H of the permanent magnet 14. Therefore, by arranging the two high permeability cores 21 at regular intervals and calculating the difference voltage signal between the induced voltage signals of the two detection coils 23, the induced voltage based on the geomagnetism B ₀ is eliminated, and the magnetic flux of the permanent magnet 14 is calculated. Only the induced voltage signal based on H can be measured.

The amplifier 16 receives the induced voltage signal output from each detection coil 23 of the magnetic sensor 15, amplifies the induced voltage signal, and outputs the amplified induced voltage signal to the rotation speed calculation means 17.
The rotation speed calculation means 17 calculates the rotation speed of the guide roll 5 based on the amplified induced voltage signal output from the amplifier 16. The rotation speed of the guide roll 5 is calculated by first inputting an amplification induced voltage signal based on both detection coils 23 and calculating a difference voltage signal between the two amplification induced voltage signals. In this case, the calculated differential voltage signal is a signal obtained by amplifying the induced voltage signal based only on the magnetic flux H of the permanent magnet 14 as described above. The differential voltage signal is calculated as a pulse-like signal because the permanent magnets 14 are installed at equal intervals in the circumferential direction of the guide roll 5. Then, the rotation speed calculation means 17 calculates the rotation speed of the guide roll 5 based on the calculated difference voltage signal.

  The slip determination means 11 inputs the rotation speed of the guide roll 5 calculated by the rotation speed calculation means 17, and compares the rotation speed of the guide roll 5 with the previously set and inputted conveyance speed of the steel strip S. Then, it is determined whether or not slip has occurred between the guide roll 5 and the steel strip S. In this case, the slip determination by the slip determination means 11 is performed by comparing the rotational speed of the guide roll 5 with the transport speed of the steel strip S, and the rotational speed of the guide roll 5 is a predetermined value with respect to the transport speed of the steel strip S. When the state is slow as described above, the occurrence of slip is detected.

When the slip determination unit 11 detects the occurrence of slip, the slip determination unit 11 outputs an alarm activation command to the alarm unit 12.
The alarm means 12 is constituted by a display of a personal computer or the like, and issues a slip occurrence alarm based on the alarm activation command output from the slip determination means 11. In this case, the warning means 12 may be configured to display the rotation speed of the guide roll 5 and the like together with the slip generation warning.

The bath roll push-in amount adjusting means 13 is installed on the guide roll 5 provided with the permanent magnets 14, and includes a support portion 26 that supports the bearing 7 and an electric jack 27 that swings the support portion 26.
One end of the support portion 26 is connected to the bearing 7 that supports the shaft portion 19 of the guide roll 5 in the zinc bath 3, and the other end extends to the outside of the zinc bath 3 bath. It is connected.
The electric jack 27 is configured such that the expansion / contraction part 28 can be extended and contracted, and the guide roll 5 is swung in the pushing direction of the steel strip S (left and right direction in FIG. 3) via a support part 26 connected to the expansion / contraction part 28. By making it possible, the pushing amount of the guide roll 5 with respect to the steel strip S can be adjusted.

Next, an effect | action in the case of preventing the slip which arises between the guide roll 5 and the steel strip S by the roll rotation speed control apparatus 1 in a bath is demonstrated.
The steel strip S that has been transported to the continuous hot dip galvanizing line 2 through the cold rolling process, the cleaning process, and the annealing process is transported into the zinc bath 3 where the hot dip Z plating process is performed. Done.
Then, the steel strip S conveyed into the zinc bath 3 is redirected to the outlet side of the zinc bath 3 by the sink roll 4 and supported by both guide rolls 5 and conveyed out of the zinc bath 2 bath. Is done.

Here, since the rolls in the bath such as the sink roll 4 and the id roll 5 are in direct contact with the steel strip S in the zinc bath 3, slipping between the rolls 4 and 5 in the bath and the steel strip S occurs. When this occurs, slip wrinkles are transferred to the surface of the steel strip S, and the quality of the steel strip S is degraded.
On the other hand, when the in-bath rolls 4 and 5 are formed in a non-driven type, the in-bath rolls 4 and 5 are caused by the frictional force between the surface of the steel strip S and the outer peripheral surface of the in-bath rolls 4 and 5. Rotates with the transport of

Therefore, the slip generated between the rolls 4 and 5 in the bath and the steel strip S compares the rotation speed of the rolls 4 and 5 in the bath with the transport speed of the steel strip S, and slips when there is a difference between the two speeds. It is possible to detect the occurrence of.
Therefore, the roll speed control device 1 in the bath detects the slip generated between the guide roll 5 and the steel strip S by constantly monitoring the rotational speed of the guide roll 5 during the transport of the steel strip S. ing.

When the conveyance of the steel strip S is started, the guide roll 5 arranged in contact with the steel strip S starts to rotate by the frictional force generated between the surface of the steel strip S and the outer peripheral surface of the guide roll 5. It will be.
When the guide roll 5 starts rotating, the magnetic sensor 15 sequentially detects the magnetic flux H generated by the permanent magnets 14 provided at equal intervals in the circumferential direction of the guide roll 5.

The magnetic sensor 15 outputs an induced voltage signal from each detection coil 23 based on the detected magnetic flux H generated by each permanent magnet 14.
The induced voltage signal output from each detection coil 23 is amplified by the amplifier 16 and input to the rotation speed calculation means 17 as an amplified induced voltage signal.
The rotation speed calculation means 17 to which the amplification induced voltage signal based on each detection coil 23 is inputted calculates a difference voltage signal between the two amplification induced voltage signals.
And the rotational speed calculation means 17 can measure the rotational speed of the guide roll 5 correctly by calculating the rotational speed of the guide roll 5 based on the differential voltage signal calculated as a pulse signal. It becomes.

  Next, the rotation speed of the guide roll 5 calculated by the rotation speed calculation means 17 is input to the slip determination means 11, which determines the input rotation speed of the guide roll 5 and the steel that is set and input in advance. It is determined whether or not slip has occurred between the guide roll 5 and the steel strip S by comparing the transport speed of the strip S. Note that this determination is made based on whether or not the rotation speed of the guide roll 5 calculated with respect to the set steel belt S conveyance speed is slower than a predetermined value.

Further, when the occurrence of slip is detected by the slip determination means 11, the slip determination means 11 outputs an alarm activation command to the alarm means 12, and the alarm means 12 determines the slip occurrence alarm and the rotation speed of the guide roll 5. Display and report to the operator.
The operator who has received the report of the slip occurrence warning refers to the amount of pushing of the guide roll 5 into the steel strip S by the electric jack 27 while referring to the shape of the steel strip S and the rotation speed of the guide roll 5 displayed on the warning means 12. adjust.

Here, there is the following method as a method for preventing slip generated between the guide roll 5 and the steel strip S by adjusting the amount of pushing of the guide roll 5 into the steel strip S.
First, in the case where slip occurs between the guide roll 5 and the steel strip S due to insufficient push-in amount of the guide roll 5 with respect to the steel strip S, the push-in amount of the guide roll 5 with respect to the steel strip S is increased. In such a case, the tension of the steel strip S is increased by increasing the pushing amount of the guide roll 5 with respect to the steel strip S, and between the surface of the steel strip S and the outer peripheral surface of the guide roll 5 as the tension increases. The slip generated between the guide roll 5 and the steel strip S can be prevented by returning the rotation of the guide roll 5 by increasing the generated frictional force.

Further, the dross (reaction product of iron (Fe) and zinc (Zn)) generated in the zinc bath 3 adheres between the guide roll 5 and the steel strip S, so that the guide roll 5 and the steel strip S In the case where slip occurs between the two, the amount by which the guide roll 5 is pushed into the steel strip S is reduced. In such a case, by reducing the amount by which the guide roll 5 is pushed into the steel strip S, the dross attached between the guide roll 5 and the steel strip S is dropped, so that the guide roll 5 and the steel strip S It is possible to prevent slip occurring between them.
Thus, according to the roll rotation speed control device 1 in the bath according to the present invention, it becomes possible to prevent the guide roll 5 and the steel strip S from slipping and to improve the quality of the plated steel sheet to be processed. It becomes possible.

Next, the roll rotation speed control device in the bath according to the second embodiment of the present invention will be described with reference to the drawings.
FIG. 6 is a front view of the roll rotation speed control device in the bath according to the second embodiment of the present invention.
The basic configuration of the in-bath roll rotation speed control device 30 according to the second embodiment of the present invention is the same as that of the in-bath roll rotation speed control device 1, and therefore, the same components are described with the same reference numerals. Is omitted.
As shown in FIG. 6, the bath roll rotation speed control device 30 includes a push-in amount control means 29 instead of the slip determination means 11 in the bath roll rotation speed control device 1.

  The push-in amount control means 29 inputs the rotation speed of the guide roll 5 calculated by the rotation speed calculation means 17 and compares the rotation speed of the guide roll 5 with the preset feeding speed of the steel strip S. Thus, it is determined whether or not slip has occurred between the guide roll 5 and the steel strip S. In this case, the determination of slip in the push-in amount control means 29 is made by comparing the rotational speed of the guide roll 5 with the transport speed of the steel strip S, and the rotational speed of the guide roll 5 is predetermined with respect to the transport speed of the steel strip S. When the state is slower than the value, the occurrence of slip is detected.

Then, when the push-in amount control means 29 detects the occurrence of slip, whether the occurrence of the slip is caused by an insufficient push-in amount with respect to the steel strip S of the guide roll 5 or between the guide roll 5 and the steel strip S. It is determined whether the dross is attached or not, and the guide roll 5 by the electric jack 27 is set so that the rotation speed of the guide roll 5 is within the predetermined value with respect to the conveyance speed of the steel strip S. The amount of pushing into the steel strip S is automatically increased or decreased according to each cause.
Further, the push-in amount control means 29 outputs an alarm activation command to the alarm means 12 when the occurrence of slip is detected.
As described above, according to the roll rotation speed control device 30 in the bath according to the present invention, it is possible to more easily prevent the guide roll 5 and the steel strip S from slipping, and the processed plated steel sheet to be processed. Quality can be improved.

It is a schematic block diagram of a continuous hot dip galvanizing line. It is a front view of the roll rotation speed control apparatus in a bath concerning a first embodiment of the present invention. It is a side view of a roll rotation speed control device in a bath. It is a side view of a magnet ring. It is a block diagram of a magnetic sensor. It is a front view of the roll rotation speed control apparatus in a bath concerning a second embodiment of the present invention. It is a schematic block diagram of the drive structure of the roll in the hot dipping bath concerning patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Roll rotation speed control apparatus in a bath 2 Continuous galvanization line 3 Zinc bath 4 Sink roll 5 Guide roll S Steel strip Z Molten zinc H Magnetic flux 7 Bearing 10 Roll rotation speed detection means 11 in a bath 11 Slip determination means 12 Alarm means 13 Bath Middle roll push-in amount adjusting means 14 Permanent magnet 15 Magnetic sensor 16 Amplifier 17 Rotational speed calculating means 18 Magnet ring 19 Shaft part 21 High permeability core 22 Exciting coil 23 Detection coil 24 Transmitter 26 Supporting part 27 Electric jack 28 Extending and retracting part 29 Pushing in Quantity control means 30 Roll rotation speed control device in bath 40 Drive structure of roll in bath for hot dip plating 41 Stator 43 Roll in bath 44 Detection means 46 Support frame 47 Shaft part 48 Object to be detected 49 Material to be plated

Claims (4)

A bath rotation speed detecting device for detecting the rotation speed of a non-driven type roll in a bath immersed in a metal bath for hot dipping,
A permanent magnet provided in the bath roll;
An in-bath roll rotation speed detection device comprising a detection sensor provided outside the metal bath and detecting the magnetic flux of the permanent magnet.   The apparatus for detecting a rotational speed of a roll in a bath according to claim 1, wherein four or more permanent magnets are provided at equal intervals in the circumferential direction of the roll in the bath. A method for controlling the rotation speed of a roll in a bath that is immersed in a metal bath for hot dipping and controls the rotation speed of a roll in a non-driven bath that supports a steel strip,
Detecting the magnetic flux of the permanent magnet provided in the roll in the bath by a detection sensor provided outside the bath of the metal bath;
Calculating the rotation speed of the roll in the bath based on the detected magnetic flux;
A step of adjusting a pushing amount of the roll in the bath against the steel strip based on the calculated rotation speed and a preset transport speed of the steel strip. Rotational speed control method. A rotation speed control device for a roll in bath for controlling the rotation speed of a non-driven bath roll that supports a steel strip and is immersed in a metal bath for hot dipping.
A permanent magnet provided in the bath roll;
A detection sensor that is provided outside the metal bath and detects the magnetic flux of the permanent magnet;
Based on the detected magnetic flux, a rotational speed calculating means for calculating the rotational speed of the roll in the bath,
A pressing amount control means for adjusting a pressing amount of the roll in the bath against the steel strip based on the calculated rotation speed and a preset transport speed of the steel strip; Rotating speed control device for roll in bath.

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