Plate end portion detection device and plate end portion detection method

Abstract

The plate end detection device includes: multiple strongly magnetic cores arranged in a width direction of the plate end detection device, each equipped with an excitation coil; multiple detection coils corresponding to the multiple strongly magnetic cores, detecting signals corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil reflecting the influence of the steel plate when an AC voltage is applied to the excitation coil of the corresponding strongly magnetic core; a voltage control unit controlling the voltage applied to the excitation coils of the multiple strongly magnetic cores; and an arithmetic processing unit detecting the position of the plate end of the steel plate based on the relationship between the change in the signal detected by the detection coils when an AC voltage is applied to the excitation coil and the position of the detection coils. When an AC voltage is applied to the excitation coil, the voltage control unit controls the voltage applied to the excitation coil of at least one of the multiple strongly magnetic cores that exists within the range of leakage magnetic flux from the strongly magnetic core with the excitation coil on which the AC voltage is applied.

Description

Technical Field

[0001] This disclosure relates to a plate end detection device and a plate end detection method. Background Technology

[0002] For example, a cooling device for cooling steel plates is equipped with multiple conveyor rollers, and the steel plates are conveyed within the cooling device while being placed on these rollers. During conveying, the steel plates may sometimes swerve due to thermal expansion of the conveyor rollers, poor flatness of the steel plates, etc. To suppress this swerving, for example, conveyor roller position control is implemented to change the position of the conveyor rollers. To perform conveyor roller position control, it is required to accurately detect the position of the ends of the steel plates in the width direction (hereinafter referred to as "plate ends").

[0003] Here, as a technique for detecting the position of the end of a steel sheet, the following technique is proposed. For example, Japanese Patent Application Publication No. 2009-250898 (Patent Document 1) discloses the following technique: while illuminating the surface of a coil on which a steel sheet is wound, the surface of the coil is photographed, and the position of the end of the coil is detected based on the brightness of the photographed image.

[0004] In addition, Japanese Patent Application Publication No. 55-147373 (Patent Document 2) discloses the following technology: using a sensor having a ferrite having three protrusions on the top and bottom, a reference coil, and a detection coil, the position of the end of a steel plate is detected based on the change in inductance of the detection coil when the reference coil generates a magnetic field, wherein the reference coil is wound around the protrusion in the center of the upper side of the ferrite, and the detection coil is wound around the protrusion in the center of the lower side of the ferrite. Summary of the Invention

[0005] The problem that the invention aims to solve However, the cooling device used to cool the steel plate is an environment where visible light and infrared light are blocked by water vapor and a large amount of water. Therefore, it is difficult to obtain an image with sufficient brightness to detect the position of the steel plate's end within such an environment. Consequently, it is difficult to detect the position of the steel plate's end while it is being transported within the cooling device using the technology described in Patent Document 1.

[0006] In contrast, the magnetic field is not affected by water vapor, large amounts of water, etc. Therefore, as described in Patent Document 2, when the position of the end of the steel plate is detected based on the change in inductance of the detection coil when the reference coil generates a magnetic field, it is possible to avoid the influence of water vapor, large amounts of water, etc.

[0007] However, in the technology described in Patent Document 2, a single sensor is used to detect the position of the steel plate's end. Therefore, when the position of the steel plate's end changes significantly in the width direction due to the steel plate's meandering motion, it becomes difficult to detect the position of the steel plate's end. Furthermore, sometimes the steel plate floats up from its normal travel position (referred to as the through line), but in this case, it is impossible to distinguish whether the change in the signal generated by the sensor is caused by a change in the position of the steel plate's end or by the floating. Therefore, the performance of detecting the position of the steel plate's end when it floats up is reduced.

[0008] Therefore, the purpose of this disclosure is to provide a plate end detection device and a plate end detection method that can detect the position of the plate end even when the position of the plate end changes significantly in the width direction due to water vapor, large amounts of water, etc., in an environment where visible light and infrared light are blocked due to water vapor, large amounts of water, etc., such as in a cooling device for cooling steel plates.

[0009] Methods for solving problems The first aspect of this disclosure is a plate end detection device for detecting the position of the end of a steel plate being transported within a cooling device for cooling a steel plate. The plate end detection device comprises: a plurality of strongly magnetic cores arranged in a direction corresponding to the width of the plate end detection device, and each core is equipped with an excitation coil; and a plurality of detection coils corresponding to the plurality of strongly magnetic cores, detecting a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil of the corresponding strongly magnetic core when an AC voltage is applied to it, and the signal reflecting the influence of the steel plate in the magnetic field generated by the excitation coil; voltage; The control unit controls the voltage applied to the excitation coils of the plurality of strongly magnetic core materials; and the arithmetic processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil. When an AC voltage is applied to the excitation coil, the voltage control unit controls the application of voltage to the excitation coil of at least one of the plurality of strongly magnetic core materials that exists within the range of leakage flux from the strongly magnetic core material on which the excitation coil on which the AC voltage is applied is provided.

[0010] The second aspect of this disclosure is a plate end detection device for detecting the position of the end of a steel plate being transported within a cooling device for cooling steel plates. The plate end detection device comprises: a strongly magnetic core material with an excitation coil; a plurality of detection coils arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, detecting a signal corresponding to the strength of the magnetic field strength obtained when an AC voltage is applied to the excitation coil, reflecting the influence of the steel plate in the magnetic field generated by the excitation coil; a voltage control unit for controlling the application of voltage to the excitation coil; and an arithmetic processing unit for detecting the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coils when an AC voltage is applied to the excitation coils and the position of the detection coils. The strongly magnetic core material and the excitation coils extend in the width direction, and the voltage control unit controls the application of AC voltage to the excitation coils of the strongly magnetic core material extending in the width direction.

[0011] The third aspect of this disclosure is a plate end detection method, which detects the position of the plate end of a steel plate being transported within a cooling device for cooling a steel plate. The plate end detection method uses a plate end detection device comprising: a plurality of strongly magnetic cores arranged in a direction corresponding to the width of the plate end detection device, each equipped with an excitation coil; a plurality of detection coils corresponding to the plurality of strongly magnetic cores, detecting a signal corresponding to the strength of the magnetic field generated by the excitation coils of the corresponding strongly magnetic cores, reflecting the influence of the steel plate; a voltage control unit controlling the voltage applied to the excitation coils of the plurality of strongly magnetic cores; and a processing unit detecting the position of the plate end of the steel plate based on the relationship between the change in the signal detected by the detection coils when an AC voltage is applied to the excitation coils and the position of the detection coils. The plate end detection method includes: a voltage control step, in which the voltage control unit controls the voltage applied to the excitation coils of the plurality of strongly magnetic core materials; a detection step, in which the plurality of detection coils detect a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil reflecting the influence of the steel plate when an AC voltage is applied to the excitation coil of the corresponding strongly magnetic core material; and an arithmetic processing step, in which the arithmetic processing unit detects the position of the plate end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil. In the voltage control step, when an AC voltage is applied to the excitation coil, the voltage applied to the excitation coil of at least one of the plurality of strongly magnetic core materials is controlled to be within the range of leakage flux from the strongly magnetic core material to which the excitation coil to which the AC voltage is applied is located.

[0012] The fourth aspect of this disclosure is a plate end detection method for detecting the position of the end of a steel plate being transported within a cooling device for cooling a steel plate. The plate end detection method uses a plate end detection device comprising: a strongly magnetic core extending in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and an excitation coil; a plurality of detection coils arranged in the width direction, detecting a signal corresponding to the strength of a magnetic field obtained by reflecting the influence of the steel plate in the magnetic field generated by the excitation coil when an AC voltage is applied to the excitation coil; a voltage control unit controlling the voltage applied to the excitation coil; and a processing unit processing the signal detected by the detection coils when an AC voltage is applied to the excitation coil. The method for detecting the end position of a steel plate is as follows: a voltage control step, in which the voltage control unit controls the application of an AC voltage to an excitation coil of a strongly magnetic core material extending in the width direction; a detection step, in which the plurality of detection coils detect a signal corresponding to the strength of a magnetic field generated by the excitation coil reflecting the influence of the steel plate when an AC voltage is applied to the corresponding excitation coil of the strongly magnetic core material; and an arithmetic processing step, in which the arithmetic processing unit detects the end position of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil.

[0013] Invention Effects According to this disclosure, a plate end detection device and a plate end detection method are provided, which can detect the position of the plate end even when the position of the plate end changes significantly in the width direction, in an environment where visible light and infrared light are blocked by water vapor, a large amount of water, such as in a cooling device for cooling steel plates. Attached Figure Description

[0014] Figure 1 This is a top view showing the overall structure of the plate end detection device according to the first embodiment of the present disclosure and an example of a steel plate conveyed by multiple conveying rollers.

[0015] Figure 2 This is a side view showing an example of the overall structure of the plate end detection device of the first embodiment and a steel plate.

[0016] Figure 3 This is a perspective view showing an example of a plurality of sensors in the first embodiment.

[0017] Figure 4 This is a front view showing an example of the structure of the sensor according to the first embodiment.

[0018] Figure 5 This is a diagram illustrating an example of a method for applying voltage to a plurality of excitation coils in the first embodiment.

[0019] Figure 6 This is a diagram illustrating an example of the flow of magnetic flux when a voltage is applied to multiple excitation coils using the voltage application method of the first embodiment.

[0020] Figure 7 This is a block diagram illustrating an example of the structure of the processing apparatus according to the first embodiment.

[0021] Figure 8 This is a flowchart illustrating an example of the plate end detection process in the first embodiment.

[0022] Figure 9 This is a diagram illustrating an example of a method for applying voltage to multiple excitation coils in the second embodiment.

[0023] Figure 10 This is a diagram illustrating an example of a method for applying voltage to multiple excitation coils in the third embodiment.

[0024] Figure 11 This is a perspective view showing an example of the sensor according to the fourth embodiment.

[0025] Figure 12 This is a front view showing an example of the sensor according to the fourth embodiment.

[0026] Figure 13 This is a block diagram illustrating an example of the structure of the processing apparatus according to the fourth embodiment.

[0027] Figure 14 This is a flowchart illustrating an example of the plate end detection process in the fourth embodiment.

[0028] Figure 15 This is a diagram illustrating an example of a method for applying voltage to multiple excitation coils of a reference example.

[0029] Figure 16 This is a diagram illustrating an example of magnetic flux flow when voltage is applied to multiple excitation coils using the voltage application method of the reference example. Detailed Implementation

[0030] [First Implementation Method] First, the first embodiment of this disclosure will be described.

[0031] Figure 1 and Figure 2The overall structure of the plate end detection device 10 according to the first embodiment of this disclosure and an example of a steel plate 14 conveyed by a plurality of conveying rollers 12 are shown. For example, a plurality of conveying rollers 12 arranged in a horizontal direction are provided in a cooling device 16 for cooling the steel plate 14. The plurality of conveying rollers 12 are arranged parallel to each other. The steel plate 14 is conveyed in the cooling device 16 in a state of being placed on the plurality of conveying rollers 12. The X-axis direction represents the width direction of the steel plate 14, and the Y-axis direction represents the conveying direction of the steel plate 14. Hereinafter, the conveying direction of the steel plate 14 is referred to as the "conveying direction", and the width direction of the steel plate 14 is referred to as the "plate width direction". In addition, the width direction of the plate end detection device 10 is referred to as the "device width direction". The device width direction is the direction corresponding to the plate width direction. The device width direction refers to the direction orthogonal to the conveying direction when viewed from the normal direction of the surface of the steel plate 14.

[0032] The plate end detection device 10 is a device for detecting the plate end (i.e., plate end 14A) of the steel plate 14 being conveyed in the cooling device 16, and has multiple sensors 18 and a processing device 20.

[0033] Multiple sensors 18 are arranged in the width direction of the device in the space created between adjacent conveyor rollers 12 and the path through which the steel plate 14 passes. The structure of each sensor 18 will be described in detail later. (Refer to...) Figure 3 and Figure 4 The sensor 18 is a non-contact magnetic sensor having a yoke 24, an excitation coil 26, and a detection coil 28. The sensor 18 is positioned on the stand 22 such that magnetic flux emitted from the yoke 24 reaches the steel plate 14 when the steel plate 14 is directly above the sensor 18. However, the sensor 18 is positioned at a distance from the steel plate 14 for heat resistance and impact resistance. Multiple sensors 18 include those located outside the steel plate 14 even when conveying a steel plate 14 of maximum width that can be conveyed within the cooling device 16. Here, the yoke is an example of a strongly magnetic core material of this disclosure.

[0034] The processing device 20 is electrically connected to a plurality of sensors 18 respectively, and applies voltage to the excitation coil 26, or detects the position of the end of the steel plate 14 based on the signal detected by the detection coil 28 corresponding to the strength of the magnetic field that reflects the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26.

[0035] Figure 3 This represents an example of multiple sensors 18 arranged along the width of the device. Figure 4This illustrates an example of the structure of each sensor 18. Multiple sensors 18 have the same structure. Each sensor 18 has a magnetic yoke 24, an excitation coil 26, a detection coil 28, and a pair of winding tubes 30. The magnetic yoke 24 is made of a magnetic material such as a ferrite core, and has a pair of core portions 32 and a connecting portion 34. The pair of core portions 32 extend in the vertical direction, and the connecting portion 34 connects the lower ends of the pair of core portions 32 to each other.

[0036] Each winding tube 30 is formed in a cylindrical shape. Each winding tube 30 is mounted on a core 32 by inserting a core 32 into the inside of each winding tube 30. The excitation coil 26 is wound around the core 32 of one of the pairs of cores 32 via the winding tube 30, and the detection coil 28 is wound around the core 32 of the other of the pairs of cores 32 via the winding tube 30.

[0037] The magnetic yoke 24 functions as a strongly magnetic core material for both the excitation coil 26 and the detection coil 28. By providing the magnetic yoke, magnetic properties can be detected with high sensitivity. Each magnetic yoke 24 is arranged with a pair of cores 32 aligned in the transport direction. Furthermore, multiple magnetic yokes 24 are arranged in a configuration that spans the width of the device. The detection coil 28 provided on each magnetic yoke 24 corresponds to the excitation coil 26 provided on the same sensor 18.

[0038] In sensor 18, the excitation coil 26 and the detection coil 28 are composed of different coils, which can be independently wound in each core 32, or a single coil can be continuously wound in each core 32 as both the excitation coil 26 and the detection coil 28. Hereinafter, as an example, the sensor 18 will be further explained using a structure in which a single coil is continuously wound in each core 32 as both the excitation coil 26 and the detection coil 28.

[0039] When the steel plate 14 is not present on the sensor 18, the magnetic flux emitted from the yoke 24 on which the excitation coil 26 is mounted is drawn into the S pole of the yoke 24 on which the detection coil 28 is mounted on the same sensor 18. On the other hand, when the steel plate 14 is present on the sensor 18, eddy currents are generated due to the time-varying magnetic flux. The eddy currents generate a magnetic field that cancels out the magnetic flux emitted from the yoke 24 on which the excitation coil 26 is mounted. The spatial distribution of the magnetic flux is canceled out by the eddy currents generated by the presence of the steel plate 14 as a conductor, thereby changing the strength of the magnetic field detected by the detection coil 28. Utilizing this phenomenon, a signal is acquired at each position of the sensor 18, corresponding to the strength of the magnetic field obtained by the detection coil 28, which reflects the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26. Based on the relationship between the amount of change in the acquired signal and the position of the sensor 18, the position of the end of the steel plate 14 can be detected. Furthermore, the signal corresponding to the strength of the magnetic field can be represented by electromagnetic characteristics such as impedance (inductance), voltage, and current.

[0040] Here, the inventors have noticed a problem when using the plate end detection device 10 to detect the position of the end of the steel plate 14. Hereinafter, the inventors will explain the problem considered by the inventors regarding the plate end detection device 10. When using the plate end detection device 10 to detect the position of the end of the steel plate 14, the inventors first considered applying voltage to the plurality of excitation coils 26 in the following manner.

[0041] Figure 15 This illustrates an example of a method for applying voltage to multiple excitation coils 26 of a reference example. Figure 15 The upper center diagram shows the relationship between the position of the sensor 18 that applies voltage to each excitation coil 26. The AC waveform W represents the AC voltage applied to the excitation coil 26 of the sensor 18 located at the position corresponding to the AC waveform W. Figure 15 The diagram in the lower middle shows the location of the sensors 18 with each excitation coil 26.

[0042] like Figure 15 As shown, the inventors considered applying AC voltage to multiple excitation coils 26 sequentially, switching the AC voltage applied to the multiple excitation coils 26 at regular intervals. Furthermore, the inventors believe that when an AC voltage is applied to the excitation coils 26, if a signal corresponding to the strength of the magnetic field reflected by the steel plate 14 in the magnetic field generated by the excitation coils 26 can be detected using a detection coil 28 provided on the same sensor 18, then, as described above, the position of the end of the steel plate 14 can be detected based on the relationship between the signal detected by the detection coil 28 and the position of the sensor 18.

[0043] However, the following insights have been gained: For example, when multiple sensors 18 are arranged close together in the width direction of the device in order to improve the resolution of detecting the position of the end of the steel plate 14, there is a problem that the AC voltage applied to the multiple excitation coils 26 is switched only at regular intervals.

[0044] Figure 16 This illustrates an example of magnetic flux flow when voltage is applied to multiple excitation coils 26 using the voltage application method of the reference example. Figure 16 The diagram illustrates the timing of applying an AC voltage to one of the multiple excitation coils 26, excitation coil 26A. During this timing, no AC voltage is applied to the excitation coils 26B and 26C located on either side of the excitation coil 26A. In this case, the permeability of the yokes 24B and 24C, which contain the excitation coils 26B and 26C, is high, and the magnetic flux M1 emanating from the N pole of the yoke 24A containing the excitation coil 26A is drawn into the S pole of the yokes 24B and 24C.

[0045] Furthermore, the S pole of yoke 24A will draw in the magnetic flux M2 that passes through the interior of yokes 24B and 24C and originates from the N pole of yokes 24B and 24C. Therefore, the magnetic flux path M from the N pole of yoke 24A to the S pole of yoke 24A disappears. Thus, the following problem exists: by simply switching the AC voltage applied to the multiple excitation coils 26 at regular intervals, the magnetic flux path M cannot be obtained. Therefore, when an AC voltage is applied to the excitation coils 26, it is impossible to detect the signal corresponding to the strength of the magnetic field reflected by the steel plate 14 in the magnetic field generated by the excitation coils 26 using the detection coils 28 of the same sensor 18.

[0046] Here, the inventor believes the reason lies in the high permeability of the magnetic yokes 24 on both sides of the excitation coil 26 that generates the magnetic field. It is believed that reducing the permeability of the magnetic yokes 24 on both sides would suffice. Furthermore, the inventor believes that the magnetic properties of the ferrite core used in the magnetic yoke 24 are non-linear. If a magnetic field of a certain intensity or higher is applied, the relative permeability (the ratio of the permeability of an object to the permeability of vacuum) approaches 1. Therefore, to reduce the permeability of the magnetic yokes 24 on both sides, a DC voltage can be applied to the excitation coils 26 of the magnetic yokes 24 when an AC voltage is applied to the excitation coil 26. The voltage application method of the first embodiment designed by the inventor will be described below.

[0047] Figure 5 This illustrates an example of a method for applying voltage to a plurality of excitation coils 26 in the first embodiment. Figure 5 The upper center diagram shows the relationship between the timing of voltage application to each excitation coil 26 and the position of the sensor 18. The AC waveform W indicates that an AC voltage is applied to the excitation coil 26 of the sensor 18 located at the position corresponding to AC waveform W, and "D" indicates that a DC voltage is applied to the excitation coil 26 of the sensor 18 located at the position corresponding to "D". Figure 5 The diagram in the lower middle shows the location of the sensors 18 with each excitation coil 26.

[0048] like Figure 5 As shown, the inventors have devised a method for applying a DC voltage to excitation coils 26 located on adjacent sides of the excitation coil 26 to which the AC voltage is applied, while sequentially applying AC voltage to multiple excitation coils 26 one by one. According to this method, when an AC voltage is applied to the excitation coils 26, a signal corresponding to the strength of the magnetic field reflected by the steel plate 14 in the magnetic field generated by the excitation coils 26 can be detected by a detection coil 28 provided on the same sensor 18. Detailed explanation follows.

[0049] Figure 6 This illustrates an example of magnetic flux flow when a voltage is applied to multiple excitation coils 26 using the voltage application method of the first embodiment. Figure 6The diagram illustrates the timing of applying an AC voltage to one of the multiple excitation coils 26A, and applying a DC voltage to the excitation coils 26B and 26C located on either side of the excitation coil 26A. When a DC voltage is applied to the excitation coils 26B and 26C, the permeability of the yokes 24B and 24C, where the excitation coils 26B and 26C are located, decreases. Therefore, a magnetic circuit is no longer formed between the yokes 24A and 24B and 24C, and a magnetic flux path M is formed from the N pole of the yoke 24A to the S pole of the yoke 24A. Thus, the magnetic flux emitted from the N pole of the yoke 24A is not drawn into the yokes 24B and 24C, but is directed towards the S pole of the yoke 24A. Consequently, by using the detection coil 28 located at the S pole of the yoke 24A, a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26 of the yoke 24A, reflecting the influence of the steel plate 14, can be detected.

[0050] Furthermore, while an example of applying a DC voltage to excitation coils 26B and 26C located adjacent to one excitation coil 26A has been given, it is also possible to apply a DC voltage to excitation coils 26 of one or more yokes 24 located close to yokes 24 to which an AC voltage has been applied. The selection of one or more yokes 24 located close to yokes 26 is based on the range of magnetic flux leakage from yokes 24 to which an AC voltage has been applied, without applying a DC voltage to the excitation coils 24 of one or more yokes 24 located close to yokes 26. That is, one or more yokes 24 located within the range of magnetic flux leakage from yokes 24 are selected as located at the aforementioned close positions. Specifically, "located close to yokes 24 to which an AC voltage has been applied" refers to the range of magnetic flux leakage from yokes 24 to which an AC voltage has been applied (specifically, the range affected by the magnetic flux emitted from yokes 24). The range of leakage flux from the yoke 24, which has an excitation coil 26 with an applied AC voltage, can be determined experimentally or analytically.

[0051] Furthermore, the selection of one or more yokes 24 located in the aforementioned proximity depends on the position of the sensor 18, which is provided with an excitation coil 26 to which an AC voltage is applied. For example, in the case of a yoke 24 located between two yokes 24 of a plurality of yokes 24 arranged along the width of the device, since there are yokes 24 on adjacent sides of the yoke 24 to which an excitation coil 26 to which an AC voltage is applied, one or more yokes 24 located on one adjacent side of the yoke 24 to which an excitation coil 26 to which an AC voltage is applied, and one or more yokes 24 located on the other adjacent side are selected as one or more yokes 24 located in the aforementioned proximity. Furthermore, in the case of the end yokes among the plurality of yokes 24 arranged along the width direction of the device, since there are only yokes 24 on one adjacent side of the yoke 24 on which the excitation coil 26 to which the AC voltage is applied is provided, one or more yokes 24 on one adjacent side of the yoke 24 on which the excitation coil 26 to which the AC voltage is applied is selected as one or more yokes 24 in the aforementioned closer position.

[0052] Thus, if a DC voltage is applied to the excitation coil 26 of one or more yokes 24 within the range of leakage flux from the excitation coil 26A, it is possible to suppress the magnetic flux emitted from the N pole of the yoke 24A on which the excitation coil 26A is provided from being drawn into one or more yokes 24 within the range of leakage flux. Therefore, by using a detection coil 28 provided at the S pole of the same yoke 24A, a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26 of the yoke 24A reflecting the influence of the steel plate 14 can be detected. Thus, according to the voltage application method of the first embodiment, a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26 reflecting the influence of the steel plate 14 can be detected using a detection coil 28 provided at the same sensor 18.

[0053] Next, the specific structure of the processing apparatus 20 of the first embodiment will be described. Figure 7 This illustrates an example of the structure of the processing device 20. The processing device 20 is a computer-based unit that performs various controls and calculations on the board-end detection device 10. The processing device 20 includes a processor 42, volatile memory 44, non-volatile memory 46, output circuitry 48, and input circuitry 50. The processor 42, volatile memory 44, non-volatile memory 46, input circuitry 50, and output circuitry 48 are interconnected via a bus 52 or similar means, enabling them to communicate with each other.

[0054] The processor 42 may be a CPU (Central Processing Unit) or an MPU (Microprocessor Unit). The volatile memory 44 may be RAM (Random Access Memory) or similar, serving as a temporary storage area for programs and data. The non-volatile memory 46 may be ROM (Read-Only Memory), HDD (Hard Disk Drive), or SSD (Solid State Drive), storing various programs, including the operating system, and various types of data.

[0055] The non-volatile memory 46 stores a program for performing the processing of detecting the position of the end of the steel plate 14 (hereinafter referred to as "plate end detection processing"). The processor 42 reads the program from the non-volatile memory 46 and executes the program using the volatile memory 44 as the working area. The processor 42 controls the output circuit 48 according to the program stored in the non-volatile memory 46, or performs calculations based on the signals input from the input circuit 50.

[0056] Alternatively, the processing device 20 can replace the processor 42 or incorporate electronic circuits such as a PLD (Programmable Logic Device) or an ASIC (Application Specific Integrated Circuit) based on the processor 42. Furthermore, some or all of the functions of the processor 42 can also be implemented using electronic circuits such as a PLD or ASIC.

[0057] The output circuit 48 is electrically connected to the excitation coils 26 of each sensor 18. The output circuit 48 is controlled by the processor 42, thereby applying voltage to each excitation coil 26. The input circuit 50 is electrically connected to the detection coils 28 of each sensor 18. When the signal output from the detection coil 28 is input to the input circuit 50, the input circuit 50 converts the analog signal output from the detection coil 28 into a digital signal using an A / D converter, and outputs the digitized signal to the processor 42.

[0058] The processor 42 reads the program for performing board end detection processing from the non-volatile memory 46, expands the read program in the volatile memory 44 and executes it, thereby performing the functions of each functional unit of the processing device 20. Specifically, the processor 42 functions as the voltage control unit 62 and the arithmetic processing unit 66.

[0059] The voltage control unit 62 is a functional unit that controls the application of voltage to the excitation coils 26 of the plurality of yokes 24 in the output circuit 48. The voltage control unit 62 sequentially selects one yoke 24 from the plurality of yokes 24 at certain time intervals and controls the application of AC voltage to the excitation coil 26 of the selected yoke 24.

[0060] In addition, when an AC voltage is applied to the excitation coil 26, the voltage control unit 62 controls the voltage applied to the excitation coil 26 of the yoke 24 located in the aforementioned proximity, so as to suppress the leakage of magnetic flux from the yoke 24 of the plurality of yokes 24 to the yoke 24 located in the proximity of the yoke 24 to the yoke 24 with the excitation coil 26 to which the AC voltage is applied.

[0061] Specifically, when the voltage control unit 62 applies an AC voltage to the excitation coil 26 of a selected yoke 24, it selects a predetermined number of yokes 24 located adjacent to the selected yoke 24 as the yokes 24 located in the aforementioned closer positions, and controls the application of a DC voltage to the excitation coil 26 of the selected yokes 24. For example, while applying an AC voltage to the excitation coil 26, the voltage control unit 62 controls the output circuit 48 to apply a DC voltage to the excitation coil 26 of the yokes 24 located in the closer positions. Therefore, leakage of magnetic flux from the yoke 24, which is provided with an excitation coil 26 to which an AC voltage has been applied, to the yoke 24 located close to the excitation coil 26 is suppressed. Thus, when an AC voltage is applied to the excitation coil 26, a signal corresponding to the strength of the magnetic field in the magnetic field generated by the excitation coil 26, which reflects the influence of the steel plate 14, is detected by the detection coil 28 provided in the same sensor 18.

[0062] When the voltage control unit 62 applies an AC voltage to the excitation coil 26 of the selected yoke 24, as an example of controlling the application of a DC voltage to the excitation coil 26 of the yoke 24 which exists within the range of leakage magnetic flux from the yoke 24 to which the AC voltage is applied, the following control can also be performed.

[0063] That is, the voltage control unit 62 may control the application of DC voltage to the excitation coils 26 of at least a predetermined number of yokes 24 that are located on adjacent single sides of the selected yoke 24 when the selected yoke 24 is located at the end.

[0064] Alternatively, the voltage control unit 62 may control the application of DC voltage to the excitation coils 26 of at least a predetermined number of yokes 24 located on adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0065] Alternatively, when the selected yoke 24 is located at the end, the voltage control unit 62 controls the application of DC voltage to the excitation coil 26 of at least one of the multiple yokes 24 located on an adjacent single side of the selected yoke 24.

[0066] Alternatively, the voltage control unit 62 may control the application of DC voltage to the excitation coils 26 of at least one of the multiple yokes 24 located on adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0067] Alternatively, when the selected yoke 24 is located at the end, the voltage control unit 62 controls the application of DC voltage to the excitation coil 26 of one of the multiple yokes 24 located on an adjacent single side of the selected yoke 24.

[0068] Alternatively, the voltage control unit 62 may control the application of DC voltage to the excitation coils 26 of one of the multiple yokes 24 located on each of the adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0069] The processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in signal detected by all the detection coils 28 and the position of the sensor 18. Specifically, the processing unit 66 acquires a signal detected by the detection coils 28 at each position of the sensor 18, corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26. For example, multiple channels for signal input from each detection coil 28 are provided in the input circuit 50. The position of each sensor 18 is assigned to each channel. When the processing unit 66 acquires a signal from each channel, it determines the position of the sensor 18 corresponding to each signal based on the identification information of each channel. Then, the processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in signal acquired at each position of the sensor 18 and the position of the sensor 18.

[0070] Figure 8 An example of the flow of board end detection processing executed by the processor 42 of the processing device 20 is shown. The board end detection process is executed by the processor 42, thereby executing the board end detection method of the board end detection device 10.

[0071] First, in step S10, the voltage control unit 62 controls the voltage applied to the excitation coils 26 of the plurality of yokes 24. Specifically, the voltage control unit 62 selects a yoke 24 from the plurality of yokes 24 and controls the application of an AC voltage to the excitation coil 26 of the selected yoke 24. Furthermore, when an AC voltage is applied to the excitation coil 26 of the selected yoke 24, the voltage control unit 62 selects a predetermined number of yokes 24 that are adjacent to the selected yoke 24 and controls the application of a DC voltage to the excitation coil 26 of the selected yoke 24. Step S10 is an example of the voltage control steps of this disclosure.

[0072] Next, in step S12, when an AC voltage is applied to the excitation coil 26 of the corresponding yoke 24, the detection coil 28 detects a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26, which reflects the influence of the steel plate 14. Step S12 is an example of the detection step of this disclosure.

[0073] Next, in step S14, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in the signal detected by the detection coil 28 and the position of the sensor 18. After step S14, the end plate detection processing ends.

[0074] As explained above, in the plate end detection device 10 of the first embodiment, the voltage control unit 62 sequentially selects one yoke 24 from a plurality of yokes 24 at regular time intervals, and controls the application of an AC voltage to the excitation coil 26 of the selected yoke 24. Furthermore, when an AC voltage is applied to the excitation coil 26 of the selected yoke 24, the voltage control unit 62 controls the application of a DC voltage to the excitation coils 26 of a predetermined number of yokes 24 located adjacent to the selected yoke 24. Therefore, leakage of magnetic flux from the yoke 24 with the AC-applied excitation coil 26 to yokes located close to the yoke 24 with the AC-applied excitation coil 26 can be suppressed. Thus, when an AC voltage is applied to the excitation coil 26, a signal corresponding to the strength of the magnetic field reflected by the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26 can be detected by the detection coil 28 provided on the same sensor 18.

[0075] Furthermore, by detecting a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil 26, which reflects the influence of the steel plate 14, using a detection coil 28 provided on the same sensor 18, it is possible to acquire the signal detected by the detection coil 28 at each position of the sensor 18. Then, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the amount of change in the acquired signal and the position of the sensor 18.

[0076] Furthermore, in the plate end detection device 10 of the first embodiment, a magnetic field unaffected by water vapor, large amounts of water, etc., is used to detect the position of the plate end of the steel plate 14. Therefore, when detecting the position of the plate end of the steel plate 14, the influence of water vapor, large amounts of water, etc., can be avoided.

[0077] Furthermore, since multiple detection coils 28 are arranged in a manner that allows the position of the end of the steel plate 14 to be detected even if the position of the end of the steel plate 14 changes significantly in the width direction of the device.

[0078] Furthermore, in the first embodiment, when an AC voltage is applied to the excitation coil 26, the voltage control unit 62 controls the application of a DC voltage to the excitation coil 26 of the yoke 24 located at a relatively close position. However, when an AC voltage is applied to the excitation coil 26, the control unit 62 can also control the application of a DC voltage to the excitation coil 26 of the yoke 24 located at a position deviating from the relatively close position, or it can control the application of a DC voltage to all remaining excitation coils 26.

[0079] [Second Implementation] Next, the second embodiment of this disclosure will be described.

[0080] In the second embodiment, the method of applying voltage to the plurality of excitation coils 26 is changed compared to the first embodiment. Figure 9 This illustrates an example of a method for applying voltage to multiple excitation coils 26 according to the second embodiment. Figure 5 Similarly, Figure 9 The upper center diagram shows the relationship between the timing of voltage application to each excitation coil 26 and the position of the sensor 18. The AC waveform W represents the AC voltage applied to the excitation coil 26 of the sensor 18 located at the position corresponding to the AC waveform W. Figure 9 The diagram in the lower middle shows the location of the sensors 18 with each excitation coil 26.

[0081] Voltage control unit 62 (reference) Figure 6The voltage control unit 62 sequentially selects one yoke 24 from a plurality of yokes 24 at regular time intervals, and controls the application of an AC voltage to the excitation coil 26 of the selected yoke 24. Furthermore, when an AC voltage is applied to the excitation coil 26 of the selected yoke 24, the voltage control unit 62 selects a predetermined number of yokes 24 located adjacent to the selected yoke 24 as the yokes 24 located in closer positions, and controls the application of an AC voltage to the excitation coil 26 of the selected yoke 24. For example, during the application of an AC voltage to the excitation coil 26, the voltage control unit 62 controls the output circuit 48 to apply an AC voltage with the same frequency and phase as the AC voltage applied to the excitation coil 26 of the yoke 24 located in a closer position. The yokes 24 located in closer positions can be selected in the same manner as in the first embodiment.

[0082] When the voltage control unit 62 applies an AC voltage to the excitation coil 26 of the selected yoke 24, as an example of controlling the application of an AC voltage to the excitation coil 26 of the yoke 24 that exists within the range of leakage magnetic flux from the yoke 24 to which the AC voltage is applied, the following control can also be performed.

[0083] That is, the voltage control unit 62 may control the application of AC voltage to the excitation coils 26 of at least a predetermined number of yokes 24 located on adjacent single sides of the selected yoke 24 when the selected yoke 24 is located at the end.

[0084] Alternatively, the voltage control unit 62 may control the application of AC voltage to the excitation coils 26 of at least a predetermined number of yokes 24 located on adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0085] Alternatively, when the selected yoke 24 is located at the end, the voltage control unit 62 controls the application of an AC voltage to the excitation coil 26 of at least one of the multiple yokes 24 located on an adjacent single side of the selected yoke 24.

[0086] Alternatively, the voltage control unit 62 may control the application of AC voltage to the excitation coils 26 of at least one of the multiple yokes 24 located on adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0087] Alternatively, when the selected yoke 24 is located at the end, the voltage control unit 62 controls the application of an AC voltage to the excitation coil 26 of one of the multiple yokes 24 located on an adjacent single side of the selected yoke 24.

[0088] Alternatively, the voltage control unit 62 may control the application of AC voltage to the excitation coils 26 of one yoke 24 located on each of the adjacent sides of the selected yoke 24 when the selected yoke 24 is located outside the end.

[0089] As in the second embodiment, when an AC voltage is applied to the excitation coil 26, if an AC voltage is applied to the excitation coil 26 of a nearby yoke 24, the magnetic flux emitted from the yoke 24 will not intersect with the magnetic flux emitted from other yokes 24, thus preventing [intersections]. Figure 16 The diagram illustrates the formation of a magnetic circuit between yoke 24A and yokes 24B and 24C. This allows a magnetic flux path M to be formed within the same sensor 18. Therefore, when an AC voltage is applied to the excitation coil 26, a signal corresponding to the strength of the magnetic field generated by the excitation coil 28, which reflects the influence of the steel plate 14, can be detected by the detection coil 28 located within the same sensor 18.

[0090] Furthermore, in the second embodiment, when an AC voltage is applied to the excitation coil 26, the voltage control unit 62 controls the application of an AC voltage to the excitation coil 26 of the yoke 24 located at a closer position. However, when an AC voltage is applied to the excitation coil 26, the control unit 62 can also control the application of an AC voltage to the excitation coil 26 of the yoke 24 located at a position deviating from the closer position.

[0091] [Third Implementation Method] Next, the third embodiment of this disclosure will be described.

[0092] In the third embodiment, the method of applying voltage to the plurality of excitation coils 26 is changed compared to the first embodiment. Figure 10 This illustrates an example of a method for applying voltage to multiple excitation coils 26 according to the third embodiment. Figure 5 Similarly, Figure 10 The upper center diagram shows the relationship between the timing of voltage application to each excitation coil 26 and the position of the sensor 18. The AC waveform W represents the AC voltage applied to the excitation coil 26 of the sensor 18 located at the position corresponding to the AC waveform W. Figure 10 The diagram in the lower middle shows the location of the sensors 18 with each excitation coil 26.

[0093] Voltage control unit 62 (reference) Figure 6Instead of switching the application of AC voltage to the excitation coils 26 of the multiple yokes 24, control is performed to apply AC voltage to all the excitation coils 26 of the multiple yokes 24.

[0094] As in the third embodiment, even without switching the application of AC voltage to the excitation coils 26 of the plurality of yokes 24, applying AC voltage to all the excitation coils 26 of the plurality of yokes 24 will prevent the magnetic flux emanating from the yoke 24 from intersecting with the magnetic flux emanating from the other yokes 24, thus preventing [the following]. Figure 15 The diagram illustrates the case where a magnetic path M is formed between yoke 24A and yokes 24B and 24C. Therefore, a magnetic flux path M can be formed within the same sensor 18, and thus, when an AC voltage is applied to the excitation coil 26, a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 26 can be detected by the detection coil 28 provided in the same sensor 18.

[0095] [Fourth Implementation Method] Next, the fourth embodiment of this disclosure will be described.

[0096] Figure 11 and Figure 12 This illustrates an example of a sensor 118 according to a fourth embodiment. In this fourth embodiment, instead of multiple sensors 18 in the first embodiment, a single sensor 118 is used. The sensor 118 includes a magnetic yoke 124, an excitation coil 126, and multiple detection coils 128. The magnetic yoke 124 is made of a magnetic material such as a ferrite core and has a pair of core portions 132 and a connecting portion 134. The pair of core portions 132 extend in the vertical direction, and the connecting portion 134 connects the lower ends of the pair of core portions 132 to each other. The magnetic yoke 124 is provided to extend in the transport direction.

[0097] An excitation coil 126 is wound via a winding tube (not shown) around one of a pair of cores 132. The excitation coil 126 is arranged to extend in the transport direction by being wound around one core 132. A plurality of detection coils 128 are arranged in the width direction of the device. Each detection coil 128 is positioned above the other core 132 of the pair of cores 132. A sensor 118 has an excitation coil 126 relative to the plurality of detection coils 128, and the excitation coil 126 is used in common with respect to the plurality of detection coils 128.

[0098] Figure 13 This illustrates an example of the structure of the processing apparatus 20 according to the fourth embodiment. The processing apparatus 20 differs from the first embodiment in that the processor 42 functions as both a voltage control unit 62 and an arithmetic processing unit 66. The voltage control unit 62 controls the output circuit 48 to apply an alternating current voltage to the excitation coil 126 of the magnetic yoke 124, which extends along the width direction of the device.

[0099] The processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in signal detected by the detection coil 128 and the position of the sensor 118. Specifically, the processing unit 66 acquires a signal detected by the detection coil 128 at each position of the detection coil 128, corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 126. For example, multiple channels for signal input from each detection coil 128 are provided in the input circuit 50. The position of each detection coil 128 is assigned to each channel. When the processing unit 66 acquires a signal from each channel, it determines the position of the detection coil 128 corresponding to each signal based on the identification information of each channel. Then, the processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in signal acquired at each position of the detection coil 128 and the position of the detection coil 128.

[0100] Figure 14 An example of the flow of board end detection processing executed by the processor 42 of the processing device 20 is shown. The board end detection process is executed by the processor 42, thereby executing the board end detection method of the board end detection device 10.

[0101] First, in step S20, the voltage control unit 62 controls the output circuit 48 to apply an AC voltage to the excitation coil 126 of the magnetic yoke 124, which is provided along the width direction of the device. Step S20 is an example of the voltage control step of this disclosure.

[0102] Next, in step S22, each detection coil 128 detects a signal corresponding to the strength of the magnetic field generated in the excitation coil 126 when an AC voltage is applied to the excitation coil 126. Step S22 is an example of the detection steps of this disclosure.

[0103] Next, in step S24, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in the signal detected by the detection coil 128 and the position of the detection coil 128. After step S24, the end plate detection processing ends. Step S24 is an example of the arithmetic processing steps of this disclosure.

[0104] As explained above, in the plate end detection device 10 of the fourth embodiment, the voltage control unit 62 controls the application of an alternating current voltage to the excitation coil 126 provided on the yoke 124. Here, the yoke 124 and the excitation coil 126 are provided to extend along the width direction of the device. Therefore, the magnetic flux emitted from the yoke 124 will not leak to other yokes. Thus, when an alternating current voltage is applied to the excitation coil 126, a signal corresponding to the strength of the magnetic field obtained by reflecting the influence of the steel plate 14 in the magnetic field generated by the excitation coil 126 can be detected by each detection coil 128.

[0105] Furthermore, by detecting the signal corresponding to the strength of the magnetic field obtained by each detection coil 128 in relation to the influence of the steel plate 14 in the magnetic field generated by the excitation coil 126, the change in magnetic field strength can be obtained at each position of the detection coil 128. Then, the arithmetic processing unit 66 detects the position of the end of the steel plate 14 based on the relationship between the change in magnetic field strength and the position of the detection coil 128.

[0106] Furthermore, in the plate end detection device 10 of the fourth embodiment, a magnetic field unaffected by water vapor, large amounts of water, etc., is used to detect the position of the plate end of the steel plate 14. Therefore, when detecting the position of the plate end of the steel plate 14, the influence of water vapor, large amounts of water, etc., can be avoided.

[0107] In addition, the multiple detection coils 28 are arranged in a way that allows the position of the end of the steel plate 14 to be detected even if the position of the end of the steel plate 14 changes significantly in the width direction of the device.

[0108] The first to fourth embodiments of this disclosure have been described above, but this disclosure is not limited to the above. In addition to the above, various modifications can be made without departing from its spirit.

[0109] The disclosure of Japanese Patent Application No. 2024-035344, filed on March 7, 2024, is incorporated herein by reference in its entirety.

[0110] Explanation of reference numerals in the attached figures 10 Plate End Detection Device 12 Conveyor Rollers 14 Steel Plate 16 Cooling device 18 sensors 20 processing devices 24 Magnetic yoke 26 Excitation Coil 28 Detection coil 118 Sensors 124 Magnetic Yoke 126 Excitation Coil 128 detection coil

Claims

1. A plate end detection device for detecting the position of the end of a steel plate being conveyed within a cooling device for cooling steel plates. The plate end detection device has the following features: Multiple strong magnetic core materials are arranged in a manner corresponding to the width direction of the plate end detection device, and each is provided with an excitation coil. Multiple detection coils, each corresponding to a multiple strongly magnetic core material, detect the signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil of the corresponding strongly magnetic core material, which reflects the influence of the steel plate, when an AC voltage is applied to the excitation coil of the corresponding strongly magnetic core material. The voltage control unit controls the voltage applied to the excitation coils of the plurality of strongly magnetic core materials; as well as The processing unit, when an AC voltage is applied to the excitation coil, detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil and the position of the detection coil. The voltage control unit controls the application of voltage to the excitation coil of at least one of the plurality of strongly magnetic cores that exists within the range of leakage magnetic flux from the strongly magnetic core provided with an excitation coil to which the AC voltage has been applied.

2. The plate end detection device as described in claim 1, The voltage control unit sequentially selects a strong magnetic core material from the plurality of strong magnetic core materials at certain time intervals, and controls the application of AC voltage to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core, control is performed to apply a DC voltage to the excitation coil of at least a predetermined number of strong magnetic cores that are located adjacent to the selected strong magnetic core.

3. The plate end detection device as described in claim 1, The voltage control unit sequentially selects a strong magnetic core material from the plurality of strong magnetic core materials at certain time intervals, and controls the application of AC voltage to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core, control is performed to apply a DC voltage to the excitation coil of at least one of the plurality of strong magnetic cores located adjacent to the selected strong magnetic core.

4. The plate end detection device as described in claim 1, The voltage control unit sequentially selects a strong magnetic core material from the plurality of strong magnetic core materials at certain time intervals, and controls the application of AC voltage to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core material, control is performed to apply an AC voltage to the excitation coils of at least a predetermined number of strong magnetic core materials that are located adjacent to the selected strong magnetic core material.

5. The plate end detection device as described in claim 1, The voltage control unit sequentially selects a strong magnetic core material from the plurality of strong magnetic core materials at certain time intervals, and controls the application of AC voltage to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core material, control is performed to apply an AC voltage to the excitation coil of at least one of the plurality of strong magnetic core materials located adjacent to the selected strong magnetic core material.

6. The plate end detection device as described in claim 1, The voltage control unit controls the application of AC voltage to all excitation coils of the plurality of strongly magnetic core materials.

7. A plate end detection device for detecting the position of the end of a steel plate being conveyed within a cooling device for cooling steel plates. The plate end detection device has the following features: Strongly magnetic core material, equipped with an excitation coil; Multiple detection coils are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and detect the signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil when an AC voltage is applied to the excitation coil, which reflects the influence of the steel plate. The voltage control unit controls the voltage applied to the excitation coil; and The processing unit, when an AC voltage is applied to the excitation coil, detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil and the position of the detection coil. The strongly magnetic core and the excitation coil are arranged to extend in the width direction. The voltage control unit controls the application of an AC voltage to the excitation coil of a strongly magnetic core material that extends in the width direction.

8. A method for detecting the end position of a steel plate being transported within a cooling device for cooling steel plates, wherein the end position of the steel plate is detected. The plate end detection method uses a plate end detection device. The plate end detection device has the following features: Multiple strong magnetic core materials are arranged in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and each is provided with an excitation coil. Multiple detection coils, each corresponding to a multiple strongly magnetic core material, detect the signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil of the corresponding strongly magnetic core material, which reflects the influence of the steel plate, when an AC voltage is applied to the excitation coil of the corresponding strongly magnetic core material. The voltage control unit controls the voltage applied to the excitation coils of the plurality of strongly magnetic core materials; as well as The processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil. The plate end detection method has the following characteristics: In the voltage control step, the voltage control unit is used to control the voltage applied to the excitation coils of the plurality of strongly magnetic core materials; The detection step involves using the plurality of detection coils to detect the signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil of the corresponding strong magnetic core material, which reflects the influence of the steel plate, when an AC voltage is applied to the excitation coil of the corresponding strong magnetic core material. as well as In the calculation and processing step, the calculation and processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil. In the voltage control step, control is performed to apply a voltage to the excitation coil of at least one of the plurality of strongly magnetic cores that exists within the range of leakage flux from the strongly magnetic core provided with an excitation coil to which the AC voltage has been applied.

9. The plate end detection method as described in claim 8, In the voltage control step, a strong magnetic core material is selected by sequentially switching from the plurality of strong magnetic core materials at certain time intervals, and an AC voltage is applied to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core, control is performed to apply a DC voltage to the excitation coil of at least a predetermined number of strong magnetic cores that are located adjacent to the selected strong magnetic core.

10. The plate end detection method as described in claim 8, In the voltage control step, a strong magnetic core material is selected by sequentially switching from the plurality of strong magnetic core materials at certain time intervals, and an AC voltage is applied to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core, control is performed to apply a DC voltage to the excitation coil of at least one of the plurality of strong magnetic cores located adjacent to the selected strong magnetic core.

11. The plate end detection method as described in claim 8, In the voltage control step, a strong magnetic core material is selected by sequentially switching from the plurality of strong magnetic core materials at certain time intervals, and an AC voltage is applied to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core material, control is performed to apply an AC voltage to the excitation coils of at least a predetermined number of strong magnetic core materials that are located adjacent to the selected strong magnetic core material.

12. The plate end detection method as described in claim 8, In the voltage control step, a strong magnetic core material is selected by sequentially switching from the plurality of strong magnetic core materials at certain time intervals, and an AC voltage is applied to the excitation coil of the selected strong magnetic core material. When an AC voltage is applied to the excitation coil of the selected strong magnetic core material, control is performed to apply an AC voltage to the excitation coil of at least one of the plurality of strong magnetic core materials located adjacent to the selected strong magnetic core material.

13. The plate end detection method as described in claim 8, In the voltage control step, AC voltage is applied to all excitation coils of the plurality of strongly magnetic core materials.

14. A method for detecting the position of the end of a steel plate being transported within a cooling device for cooling steel plates. The plate end detection method uses a plate end detection device. The plate end detection device has the following features: A strong magnetic core material is provided, extending in the width direction of the plate end detection device corresponding to the width direction of the steel plate, and an excitation coil is provided thereon; Multiple detection coils are arranged in the width direction to detect a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil when an AC voltage is applied to the excitation coil, which reflects the influence of the steel plate. The voltage control unit controls the voltage applied to the excitation coil; as well as The processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil. The plate end detection method has the following characteristics: In the voltage control step, the voltage control unit is used to control the application of an AC voltage to the excitation coil of a strongly magnetic core material that extends in the width direction. The detection step involves using the plurality of detection coils to detect a signal corresponding to the strength of the magnetic field obtained in the magnetic field generated by the excitation coil when an AC voltage is applied to the excitation coil, which reflects the influence of the steel plate. as well as In the calculation and processing step, the calculation and processing unit detects the position of the end of the steel plate based on the relationship between the change in the signal detected by the detection coil when an AC voltage is applied to the excitation coil and the position of the detection coil.

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