Control device for lifting electromagnets

Abstract

To provide a control device for a hung-up electromagnet which can accurately detect a plate thickness of a steel plate hung up by a hung-up electromagnet.SOLUTION: A control device 1 for a hung-up electromagnet has: a plate thickness magnetic flux characteristic storage part 30 for storing plate thickness magnetic flux characteristics in which a magnetic flux generated by a hung-up electromagnet 2a and a plate thickness T of a steel plate M are associated with each other, for each excitation current; an excitation current detection part 20 for detecting an excitation current flowing in a hung-up electromagnet 2a; a plate thickness magnetic flux characteristic acquisition part 40 for acquiring a plate thickness magnetic flux characteristic corresponding to an excitation current detected by the excitation current detection part 20, among the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristic storage part 30; a magnetic flux detection part 50 for detecting a magnetic flux generated by the hung-up electromagnet 2a when the excitation current flows in the hung-up electromagnet 2a; and a plate thickness detection part 60 for detecting the plate thickness T corresponding to the magnetic flux detected by the magnetic flux detection part 50, using the plate thickness magnetic flux characteristic acquired by the plate thickness magnetic flux characteristic acquisition part 40, as a plate thickness of the steel plate M.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a control device for a lifting electromagnet that controls a lifting electromagnet for lifting a steel plate by electromagnetic force.

Background Art

[0002] A control device for a lifting electromagnet that controls a lifting electromagnet for lifting a steel plate by electromagnetic force is known. As such a control device for a lifting electromagnet, for example, in Patent Document 1, a steel plate adsorption / detachment detection device for a lifting electromagnet that detects adsorption and detachment of the steel plate using a detection output of a magnetic flux detector that detects magnetic flux in a magnetic circuit formed in the lifting electromagnet and the steel plate lifted by the lifting electromagnet is known.

[0003] The steel plate adsorption / detachment detection device includes an adsorption / detachment discrimination circuit that discriminates the number of adsorbed or detached steel plates by counting pulse signals obtained by differentiating the detection output of the magnetic flux detector according to their polarities.

[0004] Thereby, when the number of steel plates lifted by the lifting electromagnet is different from the desired number, while controlling the excitation current, by detecting the magnetic flux with the magnetic flux detector, it is possible to detect underlifting or dropping of the steel plate. Therefore, selective control of the number of adsorbed steel plates can be performed easily and accurately.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in order to select and control the number of steel plates to be held as in Reference 1, first, It is necessary to accurately detect the number of steel plates lifted by the upper electromagnet. As a method for accurately detecting the number of steel plates lifted by a magnetic field, the magnetic flux and the thickness of the steel plate are used. Methods using the relationship have been proposed in the past.

[0007] Specifically, the relationship between the magnetic flux generated by the suspension electromagnet and the thickness of the steel plate is determined in advance, and the relationship From the relevant section, the plate thickness corresponding to the magnetic flux detected by the magnetic flux detector is determined. From the total plate thickness and the thickness of each steel plate, the number of steel plates being lifted by the lifting electromagnet Find the number.

[0008] Furthermore, when lifting a steel plate using a lifting electromagnet as in Reference 1, multiple lifting electromagnets are used. Magnets may be used. In this case, electricity is applied to each of the multiple suspension electromagnets. By supplying force, each lifting electromagnet can be used to lift a steel plate.

[0009] The temperature of the lifting electromagnet used to lift steel plates varies depending on the frequency of use and the environment. If the temperatures of the multiple suspension electromagnets are different, the electrical resistances of the multiple suspension electromagnets will also be different. Therefore, even if the same voltage is applied to the multiple suspension electromagnets with different electrical resistances, the suspension The current flowing through each electromagnet is different. As a result, the magnetic field generated by the multiple suspended electromagnets is different. The bundles also become uneven.

[0010] Thus, when the magnetic flux generated by the multiple suspension electromagnets is varied, the above When attempting to determine the thickness of a steel plate using the relationship between the magnetic flux and the thickness of the steel plate, as the lifting electromagnet The thickness obtained each time is different, making it difficult to accurately grasp the thickness of the steel plate.

[0011] An object of the present invention is to provide a control device for a lifting electromagnet that can accurately detect the thickness of a steel plate lifted by the lifting electromagnet There is to provide.

Means for Solving the Problem

[0012] A control device for a lifting electromagnet according to an embodiment of the present invention controls the driving of a lifting electromagnet that lifts a steel plate by electromagnetic force. The control device for the lifting electromagnet stores the plate thickness-magnetic flux characteristics in which the magnetic flux generated by the lifting electromagnet is related to the thickness of the steel plate for each excitation current A plate thickness-magnetic flux characteristic storage unit, an excitation current detection unit that detects the excitation current flowing through the lifting electromagnet, A plate thickness-magnetic flux characteristic acquisition unit that acquires the plate thickness-magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection unit among the plate thickness-magnetic flux characteristics stored in the plate thickness-magnetic flux characteristic storage unit, A magnetic flux detection unit that detects the magnetic flux generated by the lifting electromagnet when an excitation current is passed through the lifting electromagnet, and a plate thickness detection unit that uses the plate thickness-magnetic flux characteristic acquired by the plate thickness-magnetic flux characteristic acquisition unit to detect the plate thickness corresponding to the magnetic flux detected by the magnetic flux detection unit as the thickness of the steel plate (first configuration). Among the plate thickness-magnetic flux characteristics stored in the plate thickness-magnetic flux characteristic storage unit, [[ID=…]] (omitted for brevity) When there is a variation in the excitation current flowing through a plurality of lifting electromagnets, the magnetic fluxes generated by the plurality of lifting electromagnets are also different for each lifting electromagnet. As a result, the adsorption force of the steel plate by the plurality of lifting electromagnets also varies. Therefore, using the magnetic fluxes generated by the plurality of lifting electromagnets [[ID=4…]] (omitted for brevity) The adsorption force of the steel plate by the plurality of lifting electromagnets also varies. Therefore, using the magnetic fluxes generated by the plurality of lifting electromagnets ​​​​​​​​​​​​When detecting the plate thickness of the steel plate, there is a problem that the plate thickness detected for each lifting electromagnet is different. This occurs.

[0014] In contrast, the control device for the lifting electromagnet having the above-described configuration acquires the plate thickness magnetic flux characteristics corresponding to the exciting current flowing through the lifting electromagnet, and uses the acquired plate thickness magnetic flux characteristics to determine the plate thickness of the steel plate corresponding to the magnetic flux generated by the lifting electromagnet. Thereby, even when there is a variation in the exciting current flowing through the plurality of lifting electromagnets, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. Using the obtained plate thickness magnetic flux characteristics, the plate thickness of the steel plate corresponding to the magnetic flux generated by the lifting electromagnet is determined. Thus, even when there is a variation in the exciting current flowing through the plurality of lifting electromagnets, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. When the exciting current flowing through the lifting electromagnet varies, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. The plate thickness of the steel plate can be accurately detected.

[0015] In the first configuration, the plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristics for each exciting current as table data. The plate thickness magnetic flux characteristic acquisition unit acquires the plate thickness magnetic flux characteristics corresponding to the exciting current detected by the exciting current detection unit from the table data (second configuration). The plate thickness magnetic flux characteristic acquisition unit obtains the plate thickness magnetic flux characteristics corresponding to the exciting current detected by the exciting current detection unit from the table data. [[ID=2,2]]Thus, the plate thickness magnetic flux characteristics corresponding to the exciting current flowing through the lifting electromagnet can be selected from the table data pre-stored in the plate thickness magnetic flux characteristic storage unit. Therefore, based on the exciting current flowing through the lifting electromagnet, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. (Second configuration).

[0016] Thus, from the table data pre-stored in the plate thickness magnetic flux characteristic storage unit, the plate thickness magnetic flux characteristics corresponding to the exciting current flowing through the lifting electromagnet can be selected. Therefore, based on the exciting current flowing through the lifting electromagnet, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. Therefore, based on the exciting current flowing through the lifting electromagnet, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. Based on the exciting current flowing through the lifting electromagnet, the plate thickness of the steel plate lifted by the lifting electromagnet can be accurately detected. The plate thickness can be accurately detected.

[0017] In the first configuration, the plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristics for each exciting current as an approximate expression. The plate thickness magnetic flux characteristic acquisition unit acquires the plate thickness magnetic flux characteristics corresponding to the exciting current detected by the exciting current detection unit from the approximate expression (third configuration). The plate thickness magnetic flux characteristic acquisition unit obtains the plate thickness magnetic flux characteristics corresponding to the exciting current detected by the exciting current detection unit from the approximate expression. (Third configuration). The plate thickness magnetic flux characteristics corresponding to the exciting current detected by the exciting current detection unit are obtained from the approximate expression.

[0018] This allows the excitation flowing through the suspension electromagnet to be calculated from the approximate formula pre-stored in the plate thickness magnetic flux characteristic memory unit. The magnetic flux characteristics corresponding to the magnetic current can be determined. Therefore, the magnetic flux flow in the suspended electromagnet can be determined. Based on the excitation current, the thickness of the steel plate lifted by the lifting electromagnet is accurately detected. It is possible.

[0019] In any one of the first to third configurations described above, the excitation current detection unit is: One of several suspension electromagnets electrically connected in parallel to the power supply via an electrical circuit The excitation current flowing through the suspended electromagnet is detected. The plate thickness magnetic flux characteristic acquisition unit detects the excitation current flowing through one of the suspended electromagnets. Based on the excitation current flowing through the magnet, the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristics storage unit are used. The magnetic flux detection unit detects the magnetic flux generated by the one suspension electromagnet (the first (Composition of 4).

[0020] When multiple suspension electromagnets are electrically connected in parallel to the power supply in this manner, Due to temperature variations among multiple suspension electromagnets, etc., the electrical resistance of the multiple suspension electromagnets This results in variations in the excitation current flowing through the multiple suspension electromagnets. As a result, the magnetic flux generated by the multiple suspension electromagnets also changes for each suspension electromagnet, The attractive force of the steel plate on the lifting electromagnets will also vary.

[0021] In such a case, in the above configuration, one of the multiple suspension electromagnets The excitation current flowing through the magnet is detected, and based on the detected excitation current, the plurality of suspension electromagnets The thickness of the steel plate lifted by the electromagnet is detected. This allows the excitation flowing through each lifting electromagnet to be detected. Depending on the variation in current, the thickness of the steel plate lifted by the multiple lifting electromagnets is precisely adjusted. It can be detected with good accuracy. [Effects of the Invention]

[0022] A control device for a suspension electromagnet according to one embodiment of the present invention uses the magnetic flux generated by the suspension electromagnet and The plate thickness magnetic flux characteristics, which are related to the plate thickness of the steel plate, are determined in accordance with the excitation current flowing through the suspension electromagnet. The data is obtained by using the plate thickness magnetic flux characteristics obtained above. When an excitation current is passed through the suspension electromagnet, the steel corresponding to the magnetic flux generated by the suspension electromagnet Determine the thickness of the board.

[0023] As a result, when lifting a steel plate with multiple lifting electromagnets, the multiple lifting electromagnets Even if there is variation in the excitation current flowing through it, the lifted electromagnet is still lifted The thickness of the steel plate can be detected with high accuracy. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a control circuit diagram showing a schematic configuration of a suspension electromagnet device equipped with a control device for a suspension electromagnet according to one embodiment of the present invention. [Figure 2] Figure 2 shows the relationship between the magnetic flux generated by the suspension electromagnet and the thickness of the steel plate lifted by the suspension electromagnet. [Figure 3] Figure 3 is a flowchart showing the detection operation when the steel plate thickness is detected by the control device for the lifting electromagnet. [Modes for carrying out the invention]

[0025] The embodiments of the present invention will be described in detail below with reference to the drawings. The same or corresponding parts in the drawings The same symbols are used for the minutes, and their explanations are not repeated.

[0026] Figure 1 shows a suspension electromagnet device X equipped with a suspension electromagnet control device 1 according to one embodiment of the present invention. This is a control circuit diagram showing the schematic configuration. This suspension electromagnet device X consists of multiple suspension electromagnets 2a, The magnetic flux generated by 2b and 2c causes a steel plate M, etc., to be transmitted to multiple suspension electromagnets 2a, 2b, and 2c. This is a device for suctioning.

[0027] As shown in Figure 1, in the suspension electromagnet device X, multiple electromagnets are controlled by the suspension electromagnet control device 1. By controlling the drive of the air circuits 3a, 3b, and 3c, multiple suspension electromagnets 2a can be powered from the power supply 4. Power is supplied to 2b and 2c. In the suspension electromagnet device X, multiple suspension electromagnets 2a and 2b By controlling the power supplied to 2c, multiple suspension electromagnets 2a, 2b, and 2c generate The magnetic flux is controlled. Therefore, the suspension electromagnet control device 1 controls multiple electrical circuits 3a, 3 By controlling the drive of b and 3c, the magnetic attractive force of multiple suspension electromagnets 2a, 2b, and 2c is controlled. It is controlled.

[0028] In this embodiment, as will be described later, the suspension electromagnet control device 1 has multiple electrical circuits Selective drive control is performed for at least one of the electrical circuits 3a, 3b, and 3c. It is configured to allow this.

[0029] The suspension electromagnet device X of this embodiment comprises a plurality of suspension electromagnets 2a, 2b, 2c and a plurality of electric It includes circuits 3a, 3b, and 3c, and a control device 1 for the suspension electromagnet.

[0030] Multiple electrical circuits 3 are electrically connected in parallel to the multiple suspension electromagnets 2a, 2b, and 2c. Power is supplied from power source 4 via a, 3b, and 3c. Specifically, the suspension electromagnet 2a is supplied with The power supply 4 is supplied to the suspension electromagnet 2b by the electrical circuit 3. Power is supplied from power source 4 via b. The suspension electromagnet 2c is powered by electrical circuit 3c. Power is supplied from source 4. That is, multiple suspension electromagnets 2a, 2b, and 2c have a common power source. Power is supplied from power source 4. In this embodiment, multiple suspension electromagnets 2a, 2b, 2 c has a similar configuration.

[0031] Multiple suspension electromagnets 2a, 2b, 2c have search coils 5a, 5b, 5c. The Chicoil 5a detects the magnetic flux generated by the suspension electromagnet 2a. The search coil 5b is, The magnetic flux generated by the suspended electromagnet 2b is detected. The search coil 5c is connected to the suspended electromagnet 2c. The resulting magnetic flux is then detected.

[0032] Multiple electrical circuits 3a, 3b, 3c connect multiple suspended electromagnets 2a, 2b, 2c and a power supply 4. To connect electrically. Specifically, electrical circuit 3a electrically connects the suspended electromagnet 2a and the power supply 4. Connect. Electrical circuit 3b electrically connects the suspended electromagnet 2b and the power supply 4. Electrical circuit 3 c electrically connects the suspension electromagnet 2c and the power supply 4. In this embodiment, multiple electric The air circuits 3a, 3b, and 3c have similar configurations. Therefore, in the following, the electrical circuit 3a is used. I will only explain that.

[0033] The electrical circuit 3a includes a pair of switches 31 and 32, a discharge circuit 33, and a current detector 34. Power supply 4 outputs DC power at a predetermined voltage.

[0034] The pair of switches 31 and 32 are, for example, electromagnetic switches or electromagnetic contactors. One of the pair of switches 31 and 32, switch 31, is suspended from the positive terminal power line P of the power supply 4. The electromagnet 2a is electrically connected or disconnected, and the other switch 32 is connected to the negative terminal side of the power supply 4. Line N and the suspended electromagnet 2a are electrically connected or disconnected. The pair of switches 31 and 32 are The opening and closing operations are performed simultaneously in accordance with the drive signal output from the suspension electromagnet control device 1.

[0035] When the pair of switches 31 and 32 are closed, the suspended electromagnetic current is supplied from the power supply 4 via the electrical circuit 3a. DC power is supplied to transistor 2a. When the pair of switches 31 and 32 are open, power is supplied from power source 4. No DC power is supplied to the suspended electromagnet 2a. Therefore, the pair of switches 31 and 32 are powered by power supply 4 This controls the supply of DC power from the system to the suspended electromagnet 2a.

[0036] The discharge circuit 33 connects the pair of switches 31 and 32 to the suspension electromagnet 2a via power lines P and N. It is provided to electrically connect the power supply 4 and the suspension electromagnet 2. It is electrically connected in parallel to a.

[0037] The discharge circuit 33 includes a switch 35 for the discharge circuit and a resistor 36 having a predetermined resistance value. The discharge circuit 33 is configured such that the pair of switches 31 and 32 are open and the switch for the discharge circuit 35 is closed. In this state, the suspended electromagnet 2a forms a closed circuit, and the resistor 36 controls the suspended electromagnet 2a The stored power is consumed. In other words, the discharge circuit 33 discharges the suspended electromagnet 2a. .

[0038] The switch 35 for the discharge circuit is, for example, an electromagnetic switch or an electromagnetic contactor. The open / closed state of the device 35 is controlled by the suspension electromagnet control device 1. Discharge circuit switch 35 closes when the pair of switches 31 and 32 are open and the suspended electromagnet 2a is discharged. This is the state.

[0039] The current detector 34 detects the current flowing through the suspended electromagnet 2a. The output of the current detector 34 is The current is input to the suspension electromagnet control device 1. The output of the current detector 34 is input to the suspension electromagnet 2 This may be used to control the power supply from power source 4 to a.

[0040] Next, the control device 1 for the suspension electromagnet will be described. As mentioned above, multiple electrical circuits 3 a, 3b, 3c and the multiple suspension electromagnets 2a, 2b, 2c have a similar configuration. However, In the following, the drive of the electrical circuit 3a will be controlled by the suspension electromagnet control device 1. Next, we will explain how to control the drive of the suspension electromagnet 2a. Suspension electromagnet control device 1 This drives the pair of switches 31 and 32 and the switch 35 for the discharge circuit in the electrical circuit 3a. Control each of them.

[0041] Specifically, the suspension electromagnet control device 1 controls the drive of a pair of switches 31 and 32. This controls the power supply from power source 4 to the suspended electromagnet 2a. Device 1 controls the excitation current flowing through the suspension electromagnet 2a and the magnetic flux generated by the suspension electromagnet 2a. Based on this, the thickness T of the steel plate M being lifted by the lifting electromagnet device X is detected. The suspension electromagnet control device 1 controls the drive of the discharge circuit switch 35, thereby controlling the suspension electromagnet. The discharge of magnet 2a may be controlled.

[0042] For more details, the control device 1 for the suspension electromagnet consists of a current control unit 10, an excitation current detection unit 20, and a plate A thickness magnetic flux characteristic storage unit 30, a plate thickness magnetic flux characteristic acquisition unit 40, a magnetic flux detection unit 50, and a plate thickness detection unit 6 It has 0.

[0043] The current control unit 10 controls the drive of the pair of switches 31 and 32 and the switch for the discharge circuit 35. The current control unit 10 controls the pair of switches 31 and 32 and the switch for the discharge circuit 35. The current control unit 10 controls the opening and closing of the pair of switches 31 and 32. By controlling this, the power supply from power source 4 to suspension electromagnet 2a is controlled. When the pair of switches 31 and 32 are in the open state, unit 10 closes the switch 35 for the discharge circuit. By doing so, the discharge circuit 33 may be used to discharge the suspension electromagnet 2a.

[0044] The excitation current detection unit 20 energizes the suspension electromagnet 2a when the pair of switches 31 and 32 are closed. When current is flowing, the value of the excitation current detected by the current detector 34 is obtained. In other words, the excitation current detection unit 20 receives power from the power supply 4 to the suspension electromagnet 2a, and the suspension current When the steel plate M is being lifted by the magnetic device X, the flow to the lifting electromagnet 2a Detects the excitation current.

[0045] The plate thickness magnetic flux characteristic memory unit 30 stores the magnetic flux generated by the suspension electromagnet 2a and the suspended steel The plate thickness magnetic flux characteristics are stored in relation to the total plate thickness T of the plate M. This varies depending on the excitation current flowing through the suspension electromagnet 2a. The plate thickness magnetic flux characteristic memory unit 30 contains multiple The magnetic flux characteristics of the plate thickness corresponding to the number of excitation currents are stored. Note that the total plate thickness T of the steel plates M is In the following, this will also simply be referred to as the thickness of steel plate M.

[0046] In this embodiment, the plate thickness magnetic flux characteristic storage unit 30 stores, for example, the plate thickness magnetic flux characteristic for each excitation current. The properties are stored as table data. Specifically, the plate thickness magnetic flux characteristic storage unit 30 contains, The graph data shown in Figure 2 is pre-stored as table data. Here, Figure 2 shows the total plate thickness T of the steel plate M lifted by the lifting electromagnet device X, and the lifting electromagnet This graph shows the relationship between the magnetic flux generated by 2a (magnetic flux detector output) and the magnetic flux detector output. The multiple curves each show the relationship between plate thickness T and magnetic flux at different excitation currents. In other words, the multiple curves in Figure 2 each represent the magnetic flux characteristics of the plate thickness. In the example, when the magnetic flux generated in the magnetic circuit formed by the suspension electromagnet 2a and the steel plate is the same. The smaller the excitation current, the larger the plate thickness T becomes.

[0047] The plate thickness magnetic flux characteristic acquisition unit 40 acquires the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristic storage unit 30. From among them, the plate thickness magnetic flux characteristics corresponding to the excitation current value obtained by the excitation current detection unit 20 are To acquire. In this embodiment, the table data is stored in the plate thickness magnetic flux characteristic storage unit 30. Therefore, the plate thickness magnetic flux characteristic acquisition unit 40 receives the excitation current acquired by the excitation current detection unit 20. Based on the value, the plate thickness magnetic flux characteristics are obtained from the table data. Specifically, the plate The thickness magnetic flux characteristic acquisition unit 40 uses the graph in Figure 2 to obtain the excitation current characteristics acquired by the excitation current detection unit 20. Select the curve corresponding to the magnetic current.

[0048] The magnetic flux detection unit 50 detects the magnetic circuit formed by the suspension electromagnet 2a and the steel plate M. This is a magnetic flux detector that detects magnetic flux. The magnetic flux detection unit 50 is operated when a pair of switches 31 and 32 are closed. When the steel plate M is being lifted by the lifting electromagnet device X in this state, the search coil 5a Therefore, the value of the detected induced voltage is obtained. Then, the magnetic flux detection unit 50 is the search coil 5 The magnetic flux is determined by integrating the induced voltage value obtained from a. The output unit 50 uses the search coil 5a to detect the magnetic flux generated by the suspension electromagnet 2a. .

[0049] The plate thickness detection unit 60 acquires the plate thickness magnetic flux characteristics from the plate thickness magnetic flux characteristics storage unit 30 by the plate thickness magnetic flux characteristics acquisition unit 40. Using the plate thickness magnetic flux characteristics, the plate thickness T corresponding to the magnetic flux detected by the magnetic flux detection unit 50 is used. It detects the magnetic flux characteristics of the plate thickness stored in the magnetic flux characteristics storage unit 30. From graph 2, the curve corresponding to the excitation current detected by the excitation current detection unit 20 (Figure 2) (Reference) is selected by the plate thickness magnetic flux characteristic acquisition unit 40. Therefore, the plate thickness detection unit 60, The plate thickness T is obtained from the curve selected by the plate thickness magnetic flux characteristic acquisition unit 40.

[0050] In this embodiment, the suspension electromagnet control device 1 has a suspension electromagnet selection unit 70. The magnet selection unit 70 selects a plurality of lifting electromagnetic magnets in accordance with the signal input to the lifting electromagnet control device 1. Select one of the suspension electromagnets 2a, 2b, and 2c. Also, the suspension electromagnet selection unit 70 Then, select the current detector of the electrical circuit corresponding to the selected suspension electromagnet. The stone control device 1 detects the selected suspension electromagnet and the current flowing through the selected suspension electromagnet. The thickness T of the lifted steel plate M is detected using a current detector.

[0051] With the configuration of this embodiment, no matter which of the multiple suspension electromagnets is used, The thickness T of the steel plate M being lifted by the lifting electromagnet can be detected with high accuracy. In addition, in the configuration of this embodiment, there are multiple electrical circuits 3a, 3b, 3c and multiple suspension electromagnets 2 a, 2b, and 2c are electrically connected in parallel to a single power supply 4. This allows, Since it is not necessary to connect a power supply to each of the multiple suspension electromagnets 2a, 2b, and 2c, A compact and low-cost lifting electromagnet device X can be obtained.

[0052] Figure 3 shows the process of detecting the plate thickness T of the steel plate M being lifted by the lifting electromagnet 2a. This is a flowchart showing the detection operation of the upper electromagnet control device 1. Note that the thickness T of the steel plate M is When detecting, the current control unit 10 closes the pair of switches 31 and 32, The switch 35 for the discharge circuit is opened. In this state, the suspension electromagnet device X is used. Steel plate M is being lifted.

[0053] When the flow shown in Figure 3 starts (START), first in step S1, the suspension electromagnet The control device 1 determines whether a plate thickness detection command has been input. In step S1, If it is determined that a plate thickness detection command has been input (if YES), proceed to step S2. In step S2, the suspension electromagnet selection unit 70 selects from a plurality of suspension electromagnets 2a, 2b, 2c. Then, one lifting electromagnet is selected to be used to detect the thickness of the steel plate M, and the selected Select a current detector that corresponds to the suspended electromagnet.

[0054] On the other hand, if it is determined in step S1 that no plate thickness detection command has been input (N In case O, step S continues until a plate thickness detection command is input to the lifting electromagnet control device 1. Repeat the check for 1.

[0055] In the following step S3, the excitation current detection unit 20 detects the current selected in step S2. The value of the excitation current detected by the detector is obtained. In the next step S4, the magnetic flux characteristics of the plate thickness are obtained. The properties acquisition unit 40 acquires information on multiple plate thickness magnetic flux characteristics that have been pre-stored in the plate thickness magnetic flux characteristic storage unit 30. Refer to the plate thickness magnetic flux characteristics corresponding to the excitation current value obtained by the excitation current detection unit 20. Obtain it.

[0056] Subsequently, in step S5, the magnetic flux detection unit 50 searches the search coil of the selected suspension electromagnet. The value of the induced voltage detected by the method is obtained, and the obtained value of the induced voltage is integrated. By doing so, the magnetic flux is determined. In the next step S6, the plate thickness detection unit 60 determines the plate thickness magnetic flux characteristic The magnetic flux characteristics of the plate thickness obtained by the properties acquisition unit 40 are used to detect the magnetic flux by the magnetic flux detection unit 50. The plate thickness T corresponding to the magnetic flux is determined, and this determined plate thickness T is detected as the plate thickness of the steel plate M. Then, in step S7, the suspension electromagnet control device 1 displays the thickness T of the steel plate M on a display unit such as a monitor. After outputting, this flow will be terminated (END).

[0057] The control device 1 for the suspension electromagnet according to this embodiment uses the magnetic flux generated by the suspension electromagnet 2a and steel The plate thickness magnetic flux characteristics related to the plate thickness T of plate M are stored for each excitation current. A characteristic memory unit 30 and an excitation current detection unit 20 that detects the excitation current flowing through the suspension electromagnet 2a, Of the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristics storage unit 30, the excitation current detection unit 20 Plate thickness magnetic flux characteristic acquisition unit 40 acquires plate thickness magnetic flux characteristics corresponding to the excitation current detected by When an excitation current is passed through the suspension electromagnet 2a, the magnetic flux generated by the suspension electromagnet 2a is detected. The magnetic flux detection unit 50 and the plate thickness magnetic flux characteristics acquired by the plate thickness magnetic flux characteristics acquisition unit 40 are used The plate thickness T corresponding to the magnetic flux detected by the magnetic flux detection unit 50 is detected as the plate thickness of the steel plate M. It has a plate thickness detection unit 60 and

[0058] If there is variation in the excitation current flowing through multiple suspension electromagnets 2a, 2b, and 2c, The magnetic flux generated by the suspension electromagnets 2a, 2b, and 2c also varies for each suspension electromagnet. This results in, The attraction force of the steel plate M by multiple lifting electromagnets 2a, 2b, 2c also varies, so the lifting electromagnet 2 When detecting the thickness T of the steel plate M based on the magnetic flux generated by a, 2b, and 2c, the lifting electromagnetic A problem arises where the detected plate thickness T differs for each stone.

[0059] In contrast, the suspension electromagnet control device 1 having the above configuration flows to the suspension electromagnet 2a The magnetic flux characteristics of the plate thickness corresponding to the excitation current are obtained, and the obtained magnetic flux characteristics of the plate thickness are used to lift electromagnetic The plate thickness T corresponding to the magnetic flux generated by stone 2a is obtained. This allows for the determination of multiple suspension electromagnets. Even if there is variation in the excitation current flowing through 2a, 2b, and 2c, the suspension electromagnet will still be able to suspend the device. The thickness T of the raised steel plate M can be detected with high accuracy.

[0060] In this embodiment, the plate thickness magnetic flux characteristic storage unit 30 stores the plate thickness magnetic flux characteristics for each excitation current. It is stored as blue data. The plate thickness magnetic flux characteristic acquisition unit 40 acquires from the table data. The magnetic flux characteristics of the plate thickness corresponding to the excitation current detected by the excitation current detection unit 20 are obtained.

[0061] This allows the lifting electromagnetic flux characteristics to be determined from the table data pre-stored in the plate thickness magnetic flux characteristics storage unit 30. The plate thickness magnetic flux characteristics corresponding to the excitation current flowing through stone 2a can be selected. Therefore, the lifting Based on the excitation current flowing through electromagnet 2a, the steel plate M is lifted by the lifting electromagnet. Thickness T can be detected with high accuracy.

[0062] Furthermore, in this embodiment, the excitation current detection unit 20 controls the electrical circuits 3a, 3b, in relation to the power supply 4. One of the multiple suspension electromagnets 2a, 2b, and 2c that are electrically connected in parallel via 3c The excitation current flowing through the suspension electromagnet 2a is detected. The plate thickness magnetic flux characteristic acquisition unit 40 detects the suspension electromagnet 2 Based on the excitation current flowing through a, the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristics storage unit 30 are taken. To gain an advantage, the magnetic flux detection unit 50 detects the magnetic flux generated by the suspension electromagnet 2a.

[0063] In this way, multiple suspension electromagnets 2a, 2b, and 2c are electrically connected in parallel to the power supply 4. If this is the case, temperature variations in multiple suspension electromagnets 2a, 2b, and 2c may occur. Variations occur in the electrical resistance of multiple suspension electromagnets 2a, 2b, 2c, and multiple suspension electromagnets 2 Variations occur in the excitation current flowing through a, 2b, and 2c. As a result, multiple suspension electromagnets 2 The magnetic flux generated by a, 2b, and 2c also varies for each suspended electromagnet, so multiple suspended electromagnets 2a The suction force of the steel plate M also varies depending on 2b and 2c.

[0064] In such a case, in the above configuration, of the multiple suspension electromagnets 2a, 2b, 2c The excitation current flowing through one of the suspension electromagnets 2a is detected, and based on the detected excitation current, the suspension The thickness T of the steel plate M, which is lifted by the electromagnet 2a, is detected. Depending on the variation in the excitation current flowing through the stone, the steel plate M lifted by each suspension electromagnet The plate thickness T can be detected with high accuracy.

[0065] (Other embodiments) The embodiments of the present invention have been described above, but the embodiments described above are for the purpose of carrying out the present invention. This is merely an example. Therefore, it is not limited to the embodiments described above, nor does it deviate from its purpose. Within the limits of not violating the above-described embodiment, it is possible to implement it by appropriately modifying it.

[0066] In the above embodiment, the plate thickness magnetic flux characteristic memory unit 30 stores the magnetic flux generated by the suspension electromagnet 2a. The plate thickness magnetic flux characteristics, which relate to the plate thickness T of the steel plate M, are shown in the table data for each excitation current. It is stored in advance. The plate thickness magnetic flux characteristic acquisition unit 40 then uses the table data to acquire the magnetic flux characteristics. The plate thickness magnetic flux characteristics corresponding to the excitation current flowing through the suspended electromagnet 2a are obtained. However, The plate thickness magnetic flux characteristic acquisition unit uses an approximate formula pre-stored in the plate thickness magnetic flux characteristic memory unit to perform the lifting electromagnetic The plate thickness magnetic flux characteristics corresponding to the excitation current flowing through the stone may also be obtained.

[0067] Specifically, the plate thickness magnetic flux characteristic memory unit stores the magnetic flux generated by the suspended electromagnet and the plate thickness of the steel plate M. The magnetic flux characteristics of the plate thickness related to T may be stored as an approximate formula for each excitation current. i. In this case, the plate thickness magnetic flux characteristic acquisition unit uses the excitation current detected by the excitation current detection unit and Then, the magnetic flux characteristics of the plate thickness are obtained using the aforementioned approximation formula.

[0068] As a result, compared to the case where table data is stored in the plate thickness magnetic flux characteristic storage unit, the plate thickness This allows for a reduction in the amount of data stored in the magnetic flux characteristic memory unit.

[0069] Furthermore, the plate thickness magnetic flux characteristic memory unit stores the following approximate formula with the excitation current as the variable: The general formula for magnetic flux characteristics may be memorized.

[0070] In the above embodiment, the suspension electromagnet selection unit 70 is a plurality of suspension electromagnets 2a, 2b, 2c One is selected, and a current detector is used to detect the current flowing through the selected suspension electromagnet. Select. However, the lifting electromagnet selection unit selects two or more lifting electromagnets from among the multiple lifting electromagnets. You may select electromagnets and then select current detectors corresponding to each of the selected suspension electromagnets.

[0071] In the above embodiment, the timing at which the magnetic flux is detected by the magnetic flux detection unit 50 is determined by the plate thickness magnetic flux characteristics. This is after the plate thickness magnetic flux characteristics have been acquired from the plate thickness magnetic flux characteristics storage unit 30 by the characteristics acquisition unit 40. However, the timing for detecting magnetic flux by the magnetic flux detection unit is determined by the plate thickness magnetic flux characteristic acquisition unit. This can be done before acquiring the plate thickness magnetic flux characteristics from the plate thickness magnetic flux characteristics storage unit, or before the excitation current detection Depending on the unit, this may be done before detecting the excitation current.

[0072] In the above embodiment, the suspension electromagnet device X has three suspension electromagnets 2a, 2b, and 2c. However, the suspension electromagnet device may have two or fewer suspension electromagnets, or four or more. The device may have the above-mentioned suspension electromagnets.

[0073] In the above embodiment, the electrical circuit 3a of the suspension electromagnet device X has a discharge circuit 33. However However, the electrical circuit of the suspension electromagnet device does not need to have a discharge circuit.

[0074] In the above embodiment, the control device 1 for the suspension electromagnet includes a pair of switches 31 and 32 and a discharge circuit It controls the drive of the switch 35 for the discharge circuit of path 33. However, the suspension electromagnet device is suspended This is separate from the control device for the lifting electromagnet that detects the thickness of the steel plate being lifted by the upper electromagnet. It may also include a control device that controls the driving of a pair of switches and a switch for a discharge circuit. .

[0075] In the above embodiment, there are multiple electrical circuits 3a, 3b, 3c and multiple suspension electromagnets 2a, 2 b,2c are electrically connected in parallel to a single power supply 4. However, multiple Of the electrical circuits and multiple suspended electromagnets, only some are electrically connected to a single power source. They may be connected in a row. Also, multiple electrical circuits and multiple suspension electromagnets may be connected in different ways. It may be connected to a power source. [Industrial applicability]

[0076] This invention is used in a lifting electromagnet device that has a lifting electromagnet for lifting steel plates by electromagnetic force. It is possible. [Explanation of symbols]

[0077] X Lifting electromagnet device 1. Control device for lifting electromagnets 2a, 2b, 2c lifting electromagnet 3a, 3b, 3c electrical circuit 4 Power supply 5a, 5b, 5c Search Coil 31, 32 Switches 34 Current detector 10 Current control unit 20 Excitation current detection unit 30 Plate thickness magnetic flux characteristic memory section 40 Plate thickness magnetic flux characteristic acquisition section 50 Magnetic flux detection unit 60 Plate thickness detection unit 70 Lifting electromagnet selection section M steel plate P Positive side power line N (Negative) power line T plate thickness

Claims

1. A method for detecting the thickness of a steel plate, comprising: detecting the thickness of a steel plate by a control device for a lifting electromagnet that controls the drive of a lifting electromagnet that lifts a steel plate by electromagnetic force, The aforementioned suspension electromagnet control device has a plate thickness magnetic flux characteristic storage unit in which the plate thickness magnetic flux characteristic, which relates the magnetic flux generated by the suspension electromagnet to the plate thickness of the steel plate, is stored for each excitation current. The plate thickness detection method is, An excitation current detection step for detecting the excitation current flowing through the aforementioned suspension electromagnet, A plate thickness magnetic flux characteristic acquisition step is to acquire the plate thickness magnetic flux characteristic that corresponds to the excitation current detected in the excitation current detection step from among the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristic storage unit, A magnetic flux detection step for detecting the magnetic flux generated by the suspension electromagnet when an excitation current is passed through the suspension electromagnet, A plate thickness detection step in which, using the plate thickness magnetic flux characteristics obtained in the plate thickness magnetic flux characteristics acquisition step, the plate thickness corresponding to the magnetic flux detected in the magnetic flux detection step is detected as the plate thickness of the steel plate, The steps include setting the desired number of steel plates to be lifted by the aforementioned lifting electromagnet, If the number of steel plates that can be attached based on the thickness of the steel plates detected in the plate thickness detection step differs from the desired number, the step of adding or removing steel plates by controlling the excitation current flowing through the lifting electromagnet, Having, Plate thickness detection method.

2. In the plate thickness detection method according to claim 1, The plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristics for each excitation current as table data. In the plate thickness magnetic flux characteristic acquisition step, the plate thickness magnetic flux characteristic corresponding to the excitation current detected in the excitation current detection step is acquired from the table data. Plate thickness detection method.

3. In the plate thickness detection method according to claim 1, The plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristics for each excitation current as an approximate formula. In the plate thickness magnetic flux characteristic acquisition step, the plate thickness magnetic flux characteristic corresponding to the excitation current detected in the excitation current detection step is obtained from the approximation formula. Plate thickness detection method.

4. In the plate thickness detection method according to any one of claims 1 to 3, The aforementioned suspension electromagnet control device controls the driving of multiple suspension electromagnets that are electrically connected in parallel to the power supply via an electrical circuit. In the excitation current detection step, the excitation current flowing through one of the multiple suspension electromagnets electrically connected in parallel to the power supply via an electrical circuit is detected. In the plate thickness magnetic flux characteristic acquisition step, the plate thickness magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection step is acquired from the plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit. In the magnetic flux detection step, the magnetic flux generated by the one suspended electromagnet is detected. Plate thickness detection method.

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