Control device for hung-up electromagnet

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 lifting electromagnet control device that controls a lifting electromagnet that lifts a steel plate by electromagnetic force. Regarding placement. [Background technology]

[0002] A lifting electromagnet control device that controls a lifting electromagnet that lifts a steel plate by electromagnetic force is known. As such a control device for a lifting electromagnet, for example, Patent Document 1 discloses a control device for a lifting electromagnet and The magnetic flux in the magnetic circuit formed in the steel plate lifted by the lifting electromagnet is detected. The detection output of the magnetic flux detector is used to detect the attraction and release of the steel plate by the lifting electromagnet. Disengagement detection devices are known.

[0003] The steel plate attraction / detachment detection device detects a pulse signal obtained by differentiating the detection output of the magnetic flux detector. The number of adhesions or detachments of the steel plates is determined by counting the number of adhesions or detachments of the steel plates according to their polarity. It is equipped with a separation detection circuit.

[0004] This allows you to check if the number of steel plates lifted by the lifting electromagnet is different from the desired number. The steel plate is suspended by detecting the magnetic flux with a magnetic flux detector while controlling the exciting current. Therefore, the selection control of the number of steel plates to be picked up can be easily and accurately performed. can be carried out. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 59-24717 Summary of the Invention [Problem to be solved by the invention]

[0006] By the way, in order to selectively control the number of steel plates to be picked up as in the cited reference 1, first, It is necessary to detect the number of steel plates lifted by the upper electromagnet with high accuracy. As a method for detecting the number of steel plates lifted by the magnetic flux and the thickness of the steel plates with high accuracy, A method using the relationship shown below has been proposed.

[0007] Specifically, the relationship between the magnetic flux generated by the hoisting electromagnet and the thickness of the steel plate is obtained in advance, and the relationship is From the above relationship, the plate thickness corresponding to the magnetic flux detected by the magnetic flux detector is obtained. From the plate thickness and the plate thickness per steel plate, the number of steel plates lifted by the lifting electromagnet is calculated. Find the number.

[0008] In addition, when lifting a steel plate using a lifting electromagnet as in Reference 1, multiple lifting electromagnets are used. In this case, the plurality of lifting electromagnets are each provided with an electric current. By supplying force, the steel plate can be lifted by each lifting electromagnet.

[0009] The temperature of the lifting electromagnet when lifting a steel plate varies depending on the frequency of use and the environment. Thus, when the temperatures of the multiple lifting electromagnets are different, the electrical resistances of the multiple lifting electromagnets are also different. Therefore, even if the same voltage is applied to the plurality of lifting electromagnets having different electrical resistances, the lifting The current flowing through each electromagnet is different. Then, the magnetic field generated by the multiple lifting electromagnets is The bundle also varies.

[0010] In this way, when the magnetic flux generated by the plurality of hoisting electromagnets varies, If we try to calculate the thickness of the steel plate using the relationship between the magnetic flux and the thickness of the steel plate, the lifting electromagnet Since the thickness of the steel plate varies depending on the process, it is difficult to accurately determine the thickness of the steel plate.

[0011] The object of the present invention is to provide a method for accurately detecting the thickness of a steel plate lifted by a lifting electromagnet. To provide a control device for a hoisting electromagnet. [Means for solving the problem]

[0012] The lifting electromagnet control device according to one embodiment of the present invention lifts a steel plate by electromagnetic force. The lifting electromagnet control device controls the drive of the lifting electromagnet. The plate thickness magnetic flux characteristic, in which the magnetic flux is related to the plate thickness of the steel plate, is stored for each excitation current. A plate thickness magnetic flux characteristic storage unit and an excitation current detection unit that detects an excitation current flowing through the lifting electromagnet; The plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit is a plate thickness magnetic flux characteristic acquisition unit for acquiring a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the A magnetic flux detector that detects a magnetic flux generated by the lifting electromagnet when an exciting current is applied to the lifting electromagnet. The magnetic flux detection unit detects the thickness of the magnetic flux by using the plate thickness magnetic flux characteristic acquired by the plate thickness magnetic flux characteristic acquisition unit. A plate thickness corresponding to the magnetic flux detected by the flux detection unit is detected as the plate thickness of the steel plate. and a detection unit (first configuration).

[0013] When there is a variation in the excitation current flowing through a plurality of lifting electromagnets, The magnetic flux generated by the lifting electromagnets is different for each lifting electromagnet. Since the adhesion force of the plate also varies, the magnetic flux generated by the multiple lifting electromagnets is used to When detecting the thickness of the steel plate, a problem occurs in that the thickness detected by each lifting electromagnet differs. I agree.

[0014] In contrast, the lifting electromagnet control device having the above-mentioned configuration controls the excitation current flowing through the lifting electromagnet. and obtaining a plate thickness magnetic flux characteristic corresponding to the current, and using the obtained plate thickness magnetic flux characteristic, The thickness of the steel plate corresponding to the magnetic flux generated by the plurality of lifting electromagnets is calculated. Even if there is a variation in the exciting current flowing through the The plate thickness can be detected with high accuracy.

[0015] In the first configuration, the plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristic for each excitation current. The plate thickness magnetic flux characteristic acquisition unit stores the plate thickness magnetic flux characteristic as table data. The plate thickness magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection unit is obtained from the data. (Second configuration).

[0016] This allows the lifting electromagnet to determine the magnetic flux characteristic from the table data stored in advance in the plate thickness magnetic flux characteristic storage unit. It is possible to select the plate thickness magnetic flux characteristic corresponding to the flowing excitation current. The thickness of the steel plate lifted by the lifting electromagnet is precisely adjusted based on the excitation current flowing through the magnet. It can be detected with high accuracy.

[0017] In the first configuration, the plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristic for each excitation current. The plate thickness magnetic flux characteristic acquisition unit stores the excitation characteristic as an approximation formula. The plate thickness magnetic flux characteristic corresponding to the excitation current detected by the magnetic current detection unit is obtained (third structure). ).

[0018] As a result, the excitation flowing through the lifting electromagnet is calculated from the approximate equation stored in advance in the plate thickness magnetic flux characteristic storage unit. The plate thickness magnetic flux characteristic corresponding to the magnetic current can be obtained. The thickness of the steel plate lifted by the lifting electromagnet is detected with high accuracy based on the excitation current. It is possible.

[0019] In any one of the first to third configurations, the excitation current detection unit is One of multiple lifting electromagnets electrically connected in parallel to a power source via an electric circuit The plate thickness magnetic flux characteristic acquisition unit detects an excitation current flowing through the one lifting electromagnet. The plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit is calculated based on the excitation current flowing through the magnet. The magnetic flux detection unit detects the magnetic flux generated by the one hoisting electromagnet (the 4 configuration).

[0020] In this way, when a plurality of lifting electromagnets are electrically connected in parallel to the power source, The electrical resistance of the multiple lifting electromagnets varies due to temperature variations in the multiple lifting electromagnets. This causes variation in the excitation current flowing through the multiple lifting electromagnets. Then, the magnetic flux generated by the multiple lifting electromagnets also changes for each lifting electromagnet. There is also variation in the adhesive force of the steel plate depending on the number of lifting electromagnets.

[0021] In such a case, in the above-mentioned configuration, one of the plurality of lifting electromagnets An excitation current flowing through a magnet is detected, and the plurality of hoisting electromagnets are controlled based on the detected excitation current. This detects the thickness of the steel plate that is lifted by the magnet. The thickness of the steel plate lifted by the plurality of lifting electromagnets is precisely adjusted according to the variation in the electric current. It can be detected with high accuracy. Effect of the Invention

[0022] The lifting electromagnet control device according to one embodiment of the present invention is a device for controlling a magnetic flux generated by a lifting electromagnet. The plate thickness magnetic flux characteristic related to the plate thickness of the steel plate is calculated according to the excitation current flowing through the lifting electromagnet. The lifting electromagnet control device uses the plate thickness magnetic flux characteristics obtained by the above. The steel corresponding to the magnetic flux generated by the lifting electromagnet when an exciting current is passed through the lifting electromagnet. Determine the thickness of the plate.

[0023] As a result, when the steel plate is lifted by the plurality of lifting electromagnets, Even if there is a variation in the exciting current flowing through the The thickness of the steel plate can be detected with high accuracy. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a control circuit diagram showing a schematic configuration of a hoisting electromagnet device equipped with a hoisting electromagnet control device according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the relationship between the magnetic flux generated by the lifting electromagnet and the plate thickness of the steel plate lifted by the lifting electromagnet. [Diagram 3] FIG. 3 is a flowchart showing a detection operation when the lifting electromagnet control device detects the thickness of a steel plate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The same reference numerals are used for the parts and their descriptions will not be repeated.

[0026] FIG. 1 shows a lifting electromagnet device X equipped with a lifting electromagnet control device 1 according to an embodiment of the present invention. This hoisting electromagnet device X includes a plurality of hoisting electromagnets 2a, The magnetic flux generated by 2b and 2c causes the steel plate M, etc., to be attracted to the multiple hoisting electromagnets 2a, 2b, and 2c. It is a device for aspirating.

[0027] As shown in FIG. 1, in the lifting electromagnet device X, a lifting electromagnet control device 1 controls a plurality of electric By controlling the driving of the electric circuits 3a, 3b, and 3c, a plurality of lifting electromagnets 2a and 2b are connected from the power source 4. , 2b, and 2c are supplied with power. By controlling the power supplied to the lifting electromagnets 2a, 2b, and 2c, the lifting electromagnets 2a, 2b, and 2c are generated. Therefore, the lifting electromagnet control device 1 controls the magnetic flux. By controlling the driving of the electromagnets 2a, 2b, and 2c, the magnetic attraction force of the electromagnets 2a, 2b, and 2c is is controlled.

[0028] In this embodiment, as described later, the lifting electromagnet control device 1 includes a plurality of electric circuits. Selectively controlling the drive of at least one of the electric circuits 3a, 3b, and 3c. It is configured to be able to do so.

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

[0030] The plurality of lifting electromagnets 2a, 2b, and 2c are electrically connected in parallel to a plurality of electric circuits 3. Electric power is supplied from the power source 4 through the magnets 3a, 3b, and 3c. The lifting electromagnet 2b is supplied with power from a power source 4 through an electric circuit 3a. b is supplied with power from the power source 4. The lifting electromagnet 2c is supplied with power by an electric circuit 3c. That is, the plurality of lifting electromagnets 2a, 2b, and 2c are supplied with power from a common power source 4. Electric power is supplied from a power source 4. In this embodiment, the plurality of hoisting electromagnets 2a, 2b, 2 c has a similar configuration.

[0031] The plurality of lifting electromagnets 2a, 2b, and 2c each have a search coil 5a, 5b, and 5c. The search coil 5a detects the magnetic flux generated by the lifting electromagnet 2a. The search coil 5c detects the magnetic flux generated by the lifting electromagnet 2b. The resulting magnetic flux is detected.

[0032] The electric circuits 3a, 3b, and 3c connect the electromagnets 2a, 2b, and 2c to the power source 4. Specifically, the electric circuit 3a electrically connects the lifting electromagnet 2a and the power source 4. The electric circuit 3b electrically connects the lifting electromagnet 2b and the power source 4. The electric circuit 3 c electrically connects the hoisting electromagnet 2c to the power source 4. The electrical circuits 3a, 3b, and 3c have the same configuration. Therefore, in the following, only the electrical circuit 3a will be described. I will only explain about this.

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

[0034] Each of the pair of switches 31 and 32 is, for example, an electromagnetic switch or an electromagnetic contactor. One of the pair of switches 31 and 32, switch 31, is connected to the positive side power supply line P of the power supply 4 and the suspension The other switch 32 electrically connects or disconnects the electromagnet 2a to the negative pole of the power source 4. The line N and the lifting electromagnet 2a are electrically connected or disconnected. , and simultaneously perform opening and closing operations in response to a drive signal output from the lifting electromagnet control device 1.

[0035] When the pair of switches 31 and 32 are closed, the power supply 4 supplies the lifting electromagnetic force via the electric circuit 3a. When the pair of switches 31 and 32 are open, DC power is supplied to the stone 2a. No DC power is supplied to the lifting electromagnet 2a. Therefore, the pair of switches 31 and 32 are connected to the power source 4 The DC power supply to the lifting electromagnet 2a is controlled.

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

[0037] The discharge circuit 33 includes a discharge circuit switch 35 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 in an open state and the discharge circuit switch 35 is in a closed state. When in this state, a closed circuit is formed with the lifting electromagnet 2a, and the lifting electromagnet 2a is turned on by the resistor 36. That is, the discharge circuit 33 discharges the lifting electromagnet 2a. .

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

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

[0040] Next, the lifting electromagnet control device 1 will be described. As described above, the multiple electric circuits 3 a, 3b, 3c and the plurality of hoisting electromagnets 2a, 2b, 2c have the same configuration. Therefore, in the following, the lifting electromagnet control device 1 controls the driving of the electric circuit 3a. A case where the driving of the lifting electromagnet 2a is controlled by the lifting electromagnet control device 1 will be described. drives a pair of switches 31 and 32 in the electric circuit 3a and a discharge circuit switch 35. Control each one.

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

[0042] In detail, the lifting electromagnet control device 1 includes 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 0 and

[0043] The current control unit 10 controls the driving of the pair of switches 31 and 32 and the discharge circuit switch 35. The current control unit 10 controls the pair of switches 31 and 32 and the discharge circuit switch 35. The current control unit 10 controls the opening and closing of the pair of switches 31 and 32. By controlling the current, the power supply from the power source 4 to the lifting electromagnet 2a is controlled. The unit 10 closes the discharge circuit switch 35 when the pair of switches 31 and 32 are open. In this way, the lifting electromagnet 2a may be discharged by the discharge circuit 33.

[0044] The excitation current detection unit 20 detects the excitation current of the lifting electromagnet 2a when the pair of switches 31 and 32 are closed. When a current is flowing, the value of the excitation current detected by the current detector 34 is obtained. That is, the excitation current detection unit 20 detects the lifting current when power is supplied from the power source 4 to the lifting electromagnet 2a. When the steel plate M is being lifted by the magnet device X, the current flowing through the lifting electromagnet 2a Detect the excitation current.

[0045] The plate thickness magnetic flux characteristic storage unit 30 stores the magnetic flux generated by the lifting electromagnet 2a and the magnetic flux characteristic of the lifted steel. The plate thickness magnetic flux characteristic associated with the total plate thickness T of the plate M is stored. The thickness magnetic flux characteristic storage unit 30 stores a number of The sheet thickness magnetic flux characteristics corresponding to the number of excitation currents are stored. The total sheet thickness T of the steel sheet M is Hereinafter, this will also be simply referred to as the plate thickness of the 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. Specifically, the plate thickness magnetic flux characteristic storage unit 30 stores the following as table data: The graph data shown in FIG. 2 is stored in advance as table data. FIG. 2 shows the total thickness T of the steel plate M lifted by the lifting electromagnet device X and the 2a) (magnetic flux detector output) in FIG. Each of the multiple curves indicates the relationship between the plate thickness T and the magnetic flux at each excitation current. That is, each of the curves in FIG. 2 represents the plate thickness magnetic flux characteristics. In this example, the magnetic flux generated in the magnetic circuit formed by the hoisting electromagnet 2a and the steel plate is the same. The smaller the excitation current, the larger the plate thickness T.

[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. The plate thickness magnetic flux characteristic corresponding to the value of the excitation current acquired by the excitation current detection unit 20 is selected from the 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 detects the excitation current acquired by the excitation current detection unit 20. The plate thickness magnetic flux characteristic is obtained from the table data based on the value of The thick magnetic flux characteristic acquisition unit 40 obtains the excitation current acquired by the excitation current detection unit 20 from the graph of FIG. Select the curve that corresponds to the magnetizing current.

[0048] The magnetic flux detector 50 detects the magnetic flux generated in the magnetic circuit formed by the lifting electromagnet 2a and the steel plate M. The magnetic flux detector 50 detects magnetic flux when the pair of switches 31 and 32 are closed. When the steel plate M is lifted by the lifting electromagnet device X in this state, The magnetic flux detector 50 detects the induced voltage by detecting the magnetic flux of the search coil 5. The magnetic flux is calculated by integrating the induced voltage value obtained from a. The detector 50 detects the magnetic flux generated by the lifting electromagnet 2a using the search coil 5a. .

[0049] The plate thickness detection unit 60 detects the plate thickness magnetic flux characteristic acquired from the plate thickness magnetic flux characteristic storage unit 30 by the plate thickness magnetic flux characteristic acquisition unit 40. Using the plate thickness magnetic flux characteristic thus obtained, the plate thickness T corresponding to the magnetic flux detected by the magnetic flux detection unit 50 is calculated. In this embodiment, as described above, the thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit 30 is detected. From the graph in FIG. 2, a curve corresponding to the excitation current detected by the excitation current detection unit 20 ( ) 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 obtaining unit 40.

[0050] In this embodiment, the lifting electromagnet control device 1 has a lifting electromagnet selection unit 70. The magnet selection unit 70 selects a plurality of lifting magnets in response to a signal input to the lifting electromagnet control device 1. Select one of the lifting electromagnets from among the magnets 2a, 2b, and 2c. , select a current detector of the electric circuit corresponding to the selected lifting electromagnet; The stone control device 1 detects the selected lifting electromagnet and the current flowing through the selected lifting electromagnet. The plate 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 lifting electromagnets is used, The thickness T of the steel plate M lifted by the lifting electromagnet can be detected with high accuracy. In addition, in the configuration of this embodiment, a plurality of electric circuits 3a, 3b, and 3c and a plurality of lifting electromagnets 2 a, 2b, and 2c are electrically connected in parallel to one power source 4. Since there is no need to connect a power supply to each of the multiple lifting electromagnets 2a, 2b, and 2c, It is possible to obtain a compact and low-cost hoisting electromagnet device X.

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

[0053] When the flow shown in FIG. 3 starts (START), first, in step S1, the lifting electromagnet The control device 1 judges 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 (YES), the process proceeds to step S2. In step S2, the lifting electromagnet selection unit 70 selects one of the lifting electromagnets 2a, 2b, and 2c. Then, one lifting electromagnet to be used for detecting the thickness of the steel plate M is selected, and the selected Select the current detector that corresponds to the lifting electromagnet that was installed.

[0054] On the other hand, if it is determined in step S1 that the plate thickness detection command has not been input (N In the case of O), step S is performed until a plate thickness detection command is input to the lifting electromagnet control device 1. Repeat step 1.

[0055] In the next 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 plate thickness magnetic flux characteristic is The property acquisition unit 40 acquires information on a plurality of plate thickness magnetic flux characteristics stored in advance in the plate thickness magnetic flux characteristic storage unit 30. Referring to the plate thickness magnetic flux characteristic corresponding to the value of the excitation current acquired by the excitation current detection unit 20, Get the.

[0056] Then, in step S5, the magnetic flux detection unit 50 detects the search coil of the selected lifting electromagnet. The value of the induced voltage detected by the above is obtained, and the obtained value of the induced voltage is integrated. In the next step S6, the plate thickness detection unit 60 detects the plate thickness magnetic flux characteristic. The plate thickness magnetic flux characteristic acquired by the characteristic acquisition unit 40 is used to detect the plate thickness magnetic flux characteristic detected by the magnetic flux detection unit 50. The plate thickness T corresponding to the detected magnetic flux is calculated, and the calculated plate thickness T is detected as the plate thickness of the steel plate M. In step S7, the lifting electromagnet control device 1 displays the thickness T of the steel plate M on a display unit such as a monitor. After outputting the data to the , this flow ends (END).

[0057] The lifting electromagnet control device 1 according to this embodiment controls the magnetic flux and the steel generated by the lifting electromagnet 2a. The plate thickness magnetic flux characteristic associated with the plate thickness T of plate M is stored for each excitation current. A characteristic storage unit 30, and an excitation current detection unit 20 that detects an excitation current flowing through the lifting electromagnet 2a, Among the plate thickness magnetic flux characteristics stored in the plate thickness magnetic flux characteristic storage unit 30, the excitation current detection unit 20 a plate thickness magnetic flux characteristic acquisition unit 40 for acquiring a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the When an exciting current is applied to the lifting electromagnet 2a, the magnetic flux generated by the lifting electromagnet 2a is detected. The magnetic flux detection unit 50 detects the thickness of the plate and the plate thickness magnetic flux characteristic acquired by the plate thickness magnetic flux characteristic acquisition unit 40. 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. and a plate thickness detection unit 60 for detecting the plate thickness.

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

[0059] In contrast, the lifting electromagnet control device 1 having the above-mentioned configuration controls the lifting electromagnet 2a The plate thickness magnetic flux characteristic corresponding to the excitation current is obtained, and the plate thickness magnetic flux characteristic obtained is used to perform the lifting electromagnetic The plate thickness T corresponding to the magnetic flux generated by the magnet 2a is obtained. Even if there is a variation in the excitation current flowing through 2a, 2b, and 2c, the lifting electromagnets can lift the The plate thickness T of the lifted 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 characteristic for each excitation current. The plate thickness magnetic flux characteristic acquisition unit 40 acquires the plate thickness magnetic flux characteristic from the table data. Then, the plate thickness magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection unit 20 is obtained.

[0061] As a result, the lifting electromagnetic It is possible to select the plate thickness magnetic flux characteristic corresponding to the exciting current flowing through the stone 2a. Based on the excitation current flowing through the electromagnet 2a, the steel plate M is lifted by the lifting electromagnet. The thickness T can be detected with high accuracy.

[0062] In this embodiment, the excitation current detection unit 20 detects the electric circuits 3a, 3b, One of the multiple lifting electromagnets 2a, 2b, and 2c electrically connected in parallel via 3c The plate thickness magnetic flux characteristic acquisition unit 40 detects the excitation current flowing through the lifting electromagnet 2a. Based on the excitation current flowing through a, the plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit 30 is obtained. The magnetic flux detector 50 detects the magnetic flux generated by the hoisting electromagnet 2a.

[0063] In this manner, the plurality of lifting electromagnets 2a, 2b, and 2c are electrically connected in parallel to the power source 4. When the lifting electromagnets 2a, 2b, and 2c are connected to each other, the temperature of the lifting electromagnets 2a, 2b, and 2c may vary. Variations in the electrical resistance of the multiple lifting electromagnets 2a, 2b, and 2c occur, Variations occur in the excitation currents flowing through the magnets 2a, 2b, and 2c. Since the magnetic flux generated by the lifting electromagnets 2a, 2b, and 2c also varies for each lifting electromagnet, , 2b, and 2c also have variations in the suction force of the steel plate M.

[0064] In such a case, in the above-mentioned configuration, among the plurality of lifting electromagnets 2a, 2b, and 2c, The excitation current flowing through one of the lifting electromagnets 2a is detected, and the lifting The thickness T of the steel plate M lifted by the electromagnet 2a is detected. The amount of steel plate M lifted by each lifting electromagnet varies depending on the variation in the exciting current flowing through the magnet. The plate thickness T can be detected with high accuracy.

[0065] (Other embodiments) The embodiment of the present invention has been described above. The above-mentioned embodiment is for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiment and does not deviate from the spirit thereof. The above-described embodiment can be modified appropriately without departing from the scope of the present invention.

[0066] In the above embodiment, the plate thickness magnetic flux characteristic storage unit 30 stores magnetic flux generated by the lifting electromagnet 2a. The plate thickness magnetic flux characteristic, which is related to the plate thickness T of the steel plate M, is stored as table data for each excitation current. The plate thickness magnetic flux characteristic acquisition unit 40 then obtains the following from the table data: , the plate thickness magnetic flux characteristic corresponding to the excitation current flowing through the hoisting electromagnet 2a is obtained. However, The plate thickness magnetic flux characteristic acquisition unit calculates the lifting electromagnetic force by using an approximation formula stored in advance in the plate thickness magnetic flux characteristic storage unit. The plate thickness magnetic flux characteristic corresponding to the excitation current flowing through the stone may be obtained.

[0067] Specifically, the plate thickness magnetic flux characteristic storage unit stores the magnetic flux generated by the lifting electromagnet and the plate thickness of the steel plate M. The plate thickness magnetic flux characteristic associated with T may be stored as an approximate formula for each excitation current. In this case, the plate thickness magnetic flux characteristic acquisition unit detects the excitation current and The plate thickness magnetic flux characteristics are obtained using the above approximation formula.

[0068] As a result, compared to a case where table data is stored in the plate thickness magnetic flux characteristic storage unit, The amount of data to be stored in the magnetic flux characteristic storage unit can be reduced.

[0069] In addition, the plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristic, which is an approximate expression with the excitation current as a variable. A general formula for the magnetic flux characteristics may be stored.

[0070] In the above embodiment, the lifting electromagnet selection unit 70 selects the lifting electromagnets 2a, 2b, and 2c from among the plurality of lifting electromagnets 2a, 2b, and 2c. One of these is selected, and a current detector is provided to detect the current flowing through the selected lifting electromagnet. However, the lifting electromagnet selection unit selects two or more lifting electromagnets from among the plurality of lifting electromagnets. An electromagnet may be selected and a current detector may be selected that corresponds to each selected lifting electromagnet.

[0071] In the above embodiment, the timing at which the magnetic flux is detected by the magnetic flux detection unit 50 is determined based on the plate thickness magnetic flux characteristic. This is after the plate thickness magnetic flux characteristic acquisition unit 40 has acquired the plate thickness magnetic flux characteristic from the plate thickness magnetic flux characteristic storage unit 30. However, the timing of detecting the magnetic flux by the magnetic flux detection unit is determined by the plate thickness magnetic flux characteristic acquisition unit. Therefore, the thickness-magnetic flux characteristic may be obtained before the thickness-magnetic flux characteristic is acquired from the thickness-magnetic flux characteristic storage unit, or after the excitation current detection This may be before the excitation current is detected by the detection unit.

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

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

[0074] In the above embodiment, the lifting electromagnet control device 1 includes a pair of switches 31 and 32 and a discharge circuit. The lifting electromagnet device controls the driving of the discharge circuit switch 35 of the lifting electromagnet device. This is separate from the lifting electromagnet control device that detects the thickness of the steel plate being lifted by the upper electromagnet. and a control device for controlling the driving of the pair of switches and the discharge circuit switch. .

[0075] In the above embodiment, a plurality of electric circuits 3a, 3b, 3c and a plurality of hoisting electromagnets 2a, 2 b, 2c are electrically connected in parallel to one power source 4. Of the electric circuits and multiple lifting electromagnets, only a portion is electrically parallel to one power source. Also, the plurality of electric circuits and the plurality of lifting electromagnets may be connected in a row. The power supply may be connected to a power source. [Industrial Applicability]

[0076] The present invention is applied to a lifting electromagnet device having a lifting electromagnet that lifts a steel plate by electromagnetic force. It is possible. [Explanation of symbols]

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

Claims

1. A lifting electromagnet control device that controls the drive of the lifting electromagnet that lifts steel plates using electromagnetic force. There was, A plate thickness magnetic flux characteristic in which the magnetic flux generated by the hoisting electromagnet is related to the plate thickness of the steel plate. A plate thickness magnetic flux characteristic storage unit in which the plate thickness magnetic flux characteristic is stored for each excitation current; An excitation current detection unit that detects an excitation current flowing through the hoisting electromagnet; The thickness-magnetic flux characteristic stored in the thickness-magnetic flux characteristic storage unit includes the excitation current detection a plate thickness magnetic flux characteristic acquisition unit for acquiring a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the plate thickness magnetic flux characteristic acquisition unit; 、 A magnetic flux generated by the lifting electromagnet when an excitation current is applied to the lifting electromagnet is detected. A magnetic flux detection unit; The plate thickness magnetic flux characteristic acquired by the plate thickness magnetic flux characteristic acquisition unit is used to a plate thickness detection unit that detects a plate thickness corresponding to the detected magnetic flux as the plate thickness of the steel plate; having The plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristic for each excitation current as an approximate formula. And, The plate thickness magnetic flux characteristic acquisition unit acquires the thickness magnetic flux characteristic detected by the excitation current detection unit from the approximation formula. Obtain the plate thickness magnetic flux characteristics corresponding to the excitation current, Control device for lifting electromagnets.

2. A lifting electromagnet control device that controls the drive of the lifting electromagnet that lifts steel plates using electromagnetic force. There was, A plate thickness magnetic flux characteristic in which the magnetic flux generated by the hoisting electromagnet is related to the plate thickness of the steel plate. A plate thickness magnetic flux characteristic storage unit in which the plate thickness magnetic flux characteristic is stored for each excitation current; An excitation current detection unit that detects an excitation current flowing through the hoisting electromagnet; The thickness-magnetic flux characteristic stored in the thickness-magnetic flux characteristic storage unit includes the excitation current detection a plate thickness magnetic flux characteristic acquisition unit for acquiring a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the plate thickness magnetic flux characteristic acquisition unit; 、 A magnetic flux generated by the lifting electromagnet when an excitation current is applied to the lifting electromagnet is detected. A magnetic flux detection unit; The plate thickness magnetic flux characteristic acquired by the plate thickness magnetic flux characteristic acquisition unit is used to a plate thickness detection unit that detects a plate thickness corresponding to the detected magnetic flux as the plate thickness of the steel plate; having The excitation current detection unit includes a plurality of detectors electrically connected in parallel to a power supply via an electric circuit. Detecting an excitation current flowing through one of the lifting electromagnets, The plate thickness magnetic flux characteristic acquisition unit, from the plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit, Acquire a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection unit, The magnetic flux detection unit detects a magnetic flux generated by the one hoisting electromagnet. Control device for lifting electromagnets.

3. The lifting electromagnet control device according to claim 2, The plate thickness magnetic flux characteristic storage unit stores the plate thickness magnetic flux characteristic for each excitation current as table data. It is remembered, The plate thickness magnetic flux characteristic acquisition unit acquires the plate thickness magnetic flux characteristic detected by the excitation current detection unit from the table data. Obtain the plate thickness magnetic flux characteristics corresponding to the applied excitation current. Control device for lifting electromagnets.

4. The lifting electromagnet control device according to claim 1, The excitation current detection unit includes a plurality of detectors electrically connected in parallel to a power supply via an electric circuit. Detecting an excitation current flowing through one of the lifting electromagnets, The plate thickness magnetic flux characteristic acquisition unit, from the plate thickness magnetic flux characteristic stored in the plate thickness magnetic flux characteristic storage unit, Acquire a plate thickness magnetic flux characteristic corresponding to the excitation current detected by the excitation current detection unit, The magnetic flux detection unit detects a magnetic flux generated by the one hoisting electromagnet. Control device for lifting electromagnets.

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