JP2009001369A - System and method for controlling lifting magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for controlling a lifting magnet capable of saving the power supply to the lifting magnet while maintaining the working efficiency. <P>SOLUTION: The lifting magnet control system 2 comprises a magnet driving circuit 31 for supplying the power to a lifting magnet 10, a control unit 33 for controlling the power supply to the lifting magnet 10, and a load meter 20 for detecting the weight of a lifted cargo while the lifted cargo is hanged by the lifting magnet 10. The control unit 33 reduces the power supply to the lifting magnet 10 to the value corresponding to the weight if the weight of the lifted cargo detected by the load meter 20 is smaller than the predetermined value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a lifting magnet control system and a lifting magnet control method.

Generally, a lifting magnet for lifting an iron piece in cargo handling work or construction work is known. Some lifting magnets are installed in factories and others, and others are installed in vehicles. When using a lifting magnet, current is passed through a coil to excite it, and a suspended load such as an iron piece is attracted to the coil and lifted. When releasing the suspended load, the coil is demagnetized by passing a current in the opposite direction. As a document describing a method for supplying power for such excitation and demagnetization to a lifting magnet, there is, for example, Patent Document 1. In the method described in Patent Document 1, once the suspended load is attracted to the lifting magnet, the excitation voltage is lowered until the suspended load reaches the target mass to drop a part of the suspended load, thereby reducing the suspended load. The mass is adjusted.
Japanese Patent Laid-Open No. 10-332466

  The lifting magnet generates an attracting force according to the exciting current, and can lift a suspended load having a mass that does not exceed the attracting force. However, in the conventional system, even if the suspended load is lighter than the lifting magnet's attracting force, the attracting force is maintained, so that excessive power tends to be consumed. Moreover, in the method described in Patent Document 1, the suspended load exceeding the target mass is once lifted and the mass is adjusted by dropping a part of the suspended load. However, every time the suspended load is lifted, the suspended load is removed. Since the time to drop is required, work efficiency will fall.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a lifting magnet control system and a lifting magnet control method capable of reducing the power supplied to the lifting magnet while maintaining work efficiency. .

  In order to solve the above-described problems, a lifting magnet control system according to the present invention includes a magnet drive circuit that supplies power to a lifting magnet, a control unit that controls the magnitude of power, and a suspended load suspended from the lifting magnet. Mass detecting means for detecting the mass of the suspended load in a state where the control unit has a mass corresponding to the mass when the mass of the suspended load detected by the mass detecting means is smaller than a predetermined value. It is characterized by being lowered.

  The lifting magnet control method according to the present invention is a method for controlling the magnitude of power supplied to the lifting magnet, and includes an initial power supply step for supplying the lifting magnet with a preset amount of power, and the lifting magnet. And a power adjustment step for reducing the power to a magnitude corresponding to the mass when the mass of the suspended load is smaller than a predetermined value in a state where the suspended load is adsorbed and suspended.

  In the lifting magnet control system and the lifting magnet control method described above, the power supplied to the lifting magnet is reduced to a magnitude corresponding to the mass of the lifting load while the hanging load is suspended from the lifting magnet. Thereby, when the suspended load is light with respect to the attracting force of the lifting magnet, the attracting force can be reduced to a necessary and sufficient level, and excessive power consumption can be suppressed. Moreover, since the magnitude of the power supplied to the lifting magnet is made to correspond to the mass of the suspended load, it is not necessary to drop a part of the suspended load every time the suspended load is lifted, and the work efficiency can be suitably maintained.

  The lifting magnet control system further includes storage means for storing data in which the mass of the suspended load is associated with at least one of the current and voltage in the power, and the control unit is configured according to the data in the storage means. The power may be reduced. The lifting magnet control method may be characterized in that, in the power adjustment step, the power is reduced according to data in which the mass of the suspended load is associated with at least one of the current and voltage in the power. . According to these systems and methods, the magnitude of the power supplied to the lifting magnet (current and / or voltage) can be easily determined according to the data.

  The lifting magnet control system may be characterized in that the control unit maintains the magnitude of the electric power when the mass of the suspended load detected by the mass detection means is larger than a predetermined value. Further, the lifting magnet control method may be characterized in that the magnitude of the electric power is maintained when the mass of the suspended load is larger than a predetermined value during the electric power adjustment step. According to these systems and methods, even if the mass of the suspended load is large, the work can be performed safely without dropping a part of the suspended load.

  Further, the lifting magnet control system includes a first control mode for reducing the power to a magnitude corresponding to the mass when the mass of the suspended load detected by the mass detection means is smaller than a predetermined value, and the mass of the suspended load. Regardless, it may be characterized by having a second control mode for maintaining the electric power at the initially set magnitude. With the lifting magnet control system having such first and second modes, the power consumption can be reduced by reducing the power supply according to the mass of the suspended load (first control mode), or the power supply The two work methods, such as working with the load fixed at a size corresponding to the target mass of the suspended load (second control mode), can be suitably used according to the situation.

  In addition, another lifting magnet control method according to the present invention is a method for controlling the magnitude of power supplied to the lifting magnet, and an initial power supply step for supplying the lifting magnet with a preset amount of power; A first control mode for reducing the power to a magnitude corresponding to the mass when the mass of the suspended load is smaller than a predetermined value, and a second mode for maintaining the power at a preset magnitude regardless of the mass of the suspended load. And a power control step for executing any one of the control modes according to an operator's selection. The lifting magnet control method includes a power control step for executing the first and second modes described above according to the operator's selection. Accordingly, the power consumption is reduced by reducing the supply power according to the mass of the suspended load (first control mode), or the supply power is fixed to a size corresponding to the target mass of the suspended load. Two work methods such as (second control mode) can be suitably used depending on the situation.

  According to the lifting magnet control system and the lifting magnet control method of the present invention, power supplied to the lifting magnet can be reduced while maintaining work efficiency.

  Embodiments of a lifting magnet control system and a lifting magnet control method according to the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a perspective view showing a configuration of a lifting magnet vehicle 1 that is a work machine as an example of a mounting target of the lifting magnet control system according to the present embodiment. As shown in FIG. 1, a lifting magnet vehicle 1 is configured by mounting a lifting magnet 10 that attracts and captures a suspended load G such as a steel material by a magnetic force at the tip of an arm 12 of a hydraulic excavator (base machine). Yes. The lifting magnet vehicle 1 also includes a cab 14 for accommodating an operator who operates the position of the lifting magnet 10 and the excitation operation and release operation.

  The lifting magnet control system mounted on the lifting magnet vehicle 1 is configured so that an operator performs settings relating to a magnet control device (magnet control panel) 3 that supplies power to the lifting magnet 10 and at least one of current and voltage in the power. And a load meter (mass detection means) 20 for detecting the mass of the suspended load G in a state where the suspended load G is suspended from the lifting magnet 10. The magnet control device 3 is installed outside the cab 14, and the input device 4 is installed inside the cab 14. The load meter 20 is attached to the tip of the arm 12 (between the arm 12 and the lifting magnet 10).

  FIG. 2 is a block diagram showing a configuration of the lifting magnet control system 2 mounted on the lifting magnet vehicle 1 shown in FIG. As shown in FIG. 2, the lifting magnet control system 2 includes a magnet control device 3, an input device 4, and a magnet operation unit 5.

  The magnet control device 3 has a magnet drive circuit 31, a bridge driver 32, a control unit 33, and a serial communication circuit 34. The magnet drive circuit 31 is a circuit that supplies power to the lifting magnet 10, and includes an H-bridge circuit that controls the direction of the current flowing through the lifting magnet 10. The bridge driver 32 is a circuit that drives the H bridge circuit.

  The control unit 33 controls at least one of a current and a voltage in the power supplied to the lifting magnet 10 via the bridge driver 32. The control unit 33 has first and second control modes. In the first control mode, an electric signal indicating the mass of the suspended load G is received from the load cell 20, and when the mass of the suspended load G is smaller than a predetermined value, the electric power supplied to the lifting magnet 10 is the mass. This is a control mode for controlling at least one of current and voltage so as to decrease to a corresponding magnitude. The second control mode is a control mode in which the electric power supplied to the lifting magnet 10 is maintained at the initially set magnitude regardless of the mass of the suspended load G. The control unit 33 executes either one of the first and second control modes in accordance with an operator's selection input to the input device 4 described later. The control unit 33 includes, for example, a digital arithmetic processing circuit including a memory that stores a predetermined program and a CPU that reads and executes the predetermined program, and controls the bridge driver 32 according to setting input information D1 described later. To do.

  The serial communication circuit 34 is connected to the serial communication circuit 43 of the input device 4 via the wiring 16 connecting the inside and the outside of the cab 14 (see FIG. 1). Is sent to the control unit 33. The magnet drive circuit 31, the bridge driver 32, the control unit 33, and the serial communication circuit 34 are accommodated in one housing (magnet control panel 3).

  The input device 4 includes a touch panel 41, a signal processing unit 42, and a serial communication circuit 43. The touch panel 41 receives a setting input related to the current and voltage supplied to the lifting magnet 10 from the operator and displays the current setting state. The signal processing unit 42 recognizes the setting information input to the touch panel 41 and provides the setting information to the control unit 33 of the magnet control device 3 via the serial communication circuits 43 and 34. Further, the signal processing unit 42 stores the current setting information and displays it on the touch panel 41. The signal processing unit 42 includes a digital arithmetic processing circuit including a memory that stores a predetermined program and a CPU that reads and executes the predetermined program. The signal processing unit 42 and the serial communication circuit 43 are accommodated in one housing (input device 4) including the touch panel 41.

  The magnet operation unit 5 is a device for an operator to operate the excitation operation and the release operation of the lifting magnet 10, and is arranged together with the input device 4 inside the cab 14 shown in FIG. 1. The magnet operation unit 5 has two switches 51 and 52. One terminal of each of the switches 51 and 52 is connected to each other and is connected to the control unit 33 via the wiring 53 and is connected to a constant potential line inside the control unit 33. The other terminals of the switches 51 and 52 are connected to the control unit 33 via wirings 54 and 55, respectively.

  For example, when the operator presses the switch 51, a predetermined potential is transmitted to the control unit 33 via the wiring 54, and the control unit 33 controls the bridge driver 32 so that a positive direction current (excitation current) is supplied to the lifting magnet 10. To do. When the operator presses the switch 52, a predetermined potential is transmitted to the control unit 33 via the wiring 55, and the control unit 33 controls the bridge driver 32 so that a reverse current (release current) is supplied to the lifting magnet 10. Control. Alternatively, the controller 33 recognizes only the potential of the wiring 54, and when the switch 51 is pressed once, the exciting current is supplied to the lifting magnet 10, and when the switch 51 is pressed again, the release current is supplied to the lifting magnet 10. May be.

  The load meter 20 is configured by a device that converts stress applied by the suspended load G into an electrical signal, such as a device using a strain gauge (for example, a load cell). The load cell 20 is connected to the control unit 33 of the magnet control device 3 via a wire, and provides a signal indicating the mass of the suspended load G to the control unit 33 of the magnet control device 3. The signal provided to the control unit 33 is sent to the signal processing unit 42 of the input device 4 via the serial communication circuits 34 and 43. In this embodiment, the load cell 20 provides a signal to the control unit 33 of the magnet control device 3, but this signal may be provided directly to the signal processing unit 42 of the input device 4. As a means for detecting the mass of the suspended load G, instead of the load meter 20, for example, the hydraulic pressure of a cylinder (bucket cylinder or the like) for operating the attachment unit is detected, and the suspended load is detected based on the hydraulic pressure. The structure which estimates the mass of G may be sufficient.

  FIG. 3 is a circuit diagram showing a configuration of the magnet drive circuit 31. As shown in FIG. 3, the magnet drive circuit 31 includes a DC conversion unit 36, an H bridge circuit unit 37, a capacitor 38, and a current measurement unit 39.

The DC converter 36 is a circuit part for converting the AC power supply voltages V _{AC1 to} V _AC3 supplied from the three-phase AC power supply ACG into the DC power supply voltage V _DC . The DC conversion unit 36 of the present embodiment is configured by a bridge circuit including six diodes 36a to 36f, and performs three-phase full-wave rectification. In addition, the DC conversion unit may be configured by, for example, a pure bridge circuit using a thyristor or a mixed bridge circuit using a diode and a thyristor. In the case where the DC conversion unit is configured by a pure bridge circuit or a mixed bridge circuit, the thyristor is phase-controlled at a predetermined control angle by a phase control circuit (not shown).

  The H bridge circuit unit 37 is a circuit part for controlling the direction of the current supplied to the lifting magnet 10. The H-bridge circuit unit 37 includes four npn transistors 37a to 37d and four diodes electrically connected between current terminals (collector-emitter or source-drain) of the four transistors 37a to 37d. (Rectifier elements) 37e to 37h and an H bridge circuit including terminals 37i and 37j to which wirings 18a and 18b for supplying current to the lifting magnet 10 are connected.

  Specifically, one current terminal of the transistor 37a is electrically connected to the positive output terminal 36g of the DC converter 36, and the other current terminal of the transistor 37a is electrically connected to the terminal 37i. . One current terminal of the transistor 37 b is electrically connected to the terminal 37 i, and the other current terminal of the transistor 37 b is electrically connected to the negative output terminal 36 h of the DC conversion unit 36. One current terminal of the transistor 37c is electrically connected to the positive output terminal 36g of the DC converter 36, and the other current terminal of the transistor 37c is electrically connected to the terminal 37j. One current terminal of the transistor 37d is electrically connected to the terminal 37j, and the other current terminal of the transistor 37d is electrically connected to the negative output terminal 36h of the DC converter 36. The anodes of the diodes 37e to 37h are electrically connected to the other current terminals of the transistors 37a to 37d, respectively. The cathodes of the diodes 37e to 37h are electrically connected to the one current terminals of the transistors 37a to 37d, respectively. It is connected to the.

The control terminals (bases or gates) of the transistors 37a to 37d are electrically connected to the bridge driver 32, and the conduction state between the current terminals of the transistors 37a to 37d is a control current (from the bridge driver 32). Or control voltage). For example, when the control current to the control terminal of the transistor 37a and 37d are provided, the exciting current _{I 1} in the positive direction flows transistor 37a, the terminal 37i, the lifting magnet 10, the terminal 37j, and the order of the transistor 37d. Further, when the control current to the control terminal of the transistor 37b and 37c are provided, reverse release current (demagnetizing current) _{I 2} is, transistor 37c, the terminal 37j, the lifting magnet 10, the terminal 37i, and the order of the transistor 37b ( That is, a reverse direction) flows through the excitation current I _1.

  The bridge driver 32 makes any of the transistors 37 a to 37 d conductive according to the output signal of the control unit 33. The control unit 33 determines which of the transistors 37a to 37d is to be conducted based on the signal provided from the magnet operation unit 5 illustrated in FIG. Further, the bridge driver 32 intermittently turns on the transistors 37a to 37d as necessary, and adjusts the voltage supplied to the lifting magnet 10 by pulse width modulation (PWM). The PWM pulse width is controlled by the control unit 33, and the control unit 33 determines the PWM pulse width based on the set input information D1 from the input device 4 (see FIG. 2).

The capacitor 38 is provided to absorb and regenerate the energy accumulated in the lifting magnet 10 when the exciting current I ₁ to the lifting magnet 10 is switched to the release current I ₂ . The capacitor 38 is electrically connected between the positive output terminal 36g and the negative output terminal 36h of the DC converter 36. Instead of the capacitor 38 or in parallel with the capacitor 38, an energy discharging resistor 61 may be provided. In this case, it is more preferable to provide switch means 62 such as a transistor in series with the resistor 61.

The current measuring unit 39 is a circuit part for measuring the magnitude of the current flowing through the lifting magnet 10. The current measuring unit 39 according to the present embodiment includes a shunt resistor 39a provided in series with the wiring 18b, and outputs the voltage across the shunt resistor 39a to the A / D converter 39b. The A / D converter 39 b converts the voltage value at both ends into a digital signal and provides the digital signal to the control unit 33. Control unit 33, for example, when released current I ₂ of the process such that end the release operation upon reaching a predetermined value, referring to the digital signal. The current measuring unit may include a current sensor instead of the shunt resistor 39a.

Next, the lifting magnet control method according to the present embodiment will be described while explaining the operation of the lifting magnet control system having the above configuration. FIG. 4 is a flowchart showing a lifting magnet control method according to the present embodiment. 5A and 5B show the voltage applied to both ends of the lifting magnet 10 (FIG. 5A) and the current supplied to the lifting magnet 10 (FIG. 5B), respectively. It is a graph which shows a time waveform. As described above, the voltage applied to the lifting magnet 10 is adjusted by PWM, but FIG. 5A shows the value of the effective voltage obtained by averaging the voltage change in PWM over time. . Further, FIG. 5 (a), the the sign of the voltage and current in (b) is in the direction of the excitation current I ₁ shown in FIG. 3 as positive.

In the lifting magnet control method of this embodiment, as shown in FIG. 4, first, initial power setting and mode selection are performed (step S1). In step S <b> 1, an initial value of the magnitude of electric power supplied to the lifting magnet 10 is set according to, for example, the maximum load (predetermined value) of the suspended load to be suspended by the lifting magnet 10. Here, Table 1 is a table showing an example of initial setting values of the overshoot excitation voltage V _OS , the overexcitation excitation voltage V _OE , the rated excitation voltage V _RA , and the release voltage V _RE shown in FIG. Each initial setting value is predetermined according to the maximum load of the suspended load. Data including the contents of Table 1, that is, data in which the maximum load of the suspended load is associated with the magnitudes of the excitation voltage and the release voltage are stored in, for example, the signal processing unit 42 (see FIG. 2) of the input device 4. (Memory). Then, when the operator inputs the maximum load of the suspended load via the touch panel 41, the initial setting values of the voltages V _OS , V _OE , V _RA and V _RE corresponding to the maximum load are selected based on the data. Then, it is sent to the control unit 33 as setting input information D1 (see FIG. 2).

  In this embodiment, as described above, the voltage applied to the lifting magnet (excitation voltage and release voltage) and the maximum load of the suspended load are associated in advance, but the supply current to the lifting magnet (excitation current or release) Current or both) and the maximum load of the suspended load may be associated in advance, and both the applied voltage and the supply current may be associated with the maximum load of the suspended load.

  In step S1, either one of the first and second control modes is selected by the operator via the touch panel 41. The selected control mode is recognized by the signal processing unit 42.

Subsequently, when the switch 51 (or 52) of the magnet operation unit 5 is operated by the operator (step S2: time t ₁ shown in FIG. 5), the control unit 33 starts excitation of the lifting magnet 10 (step S2). S3: Initial power supply step). In other words, the bridge driver 32 that has received an instruction from the control unit 33 causes the transistors 37 a and 37 d of the H bridge circuit unit 37 to conduct. As a result, the exciting current I ₁ flows through the lifting magnet 10.

Control unit 33, in the first period _{T 1} shown in FIG. 5, the excitation voltage to increase the duty ratio of the PWM (effective value) and the maximum value _{V OS.} The period T ₁ called overshoot period (OS period) is a period for starting up the exciting current I ₁ to the lifting magnet 10 in a short time. The control unit 33, in the next period _{T 2} of the period _{T 1,} lowers the duty ratio of the PWM, and the excitation voltage (effective value) _V OE _{(<V OS).} The period T ₂ designated as over-excited period (OE period) is a period during which temporarily increase the force of the lifting magnet 10 so that the suspended load can be easily captured. The control unit 33, at the beginning of the next period _{T 3} period _{T 2,} and further reduce the duty ratio of the PWM, and the excitation voltage (effective value) _V RA _{(<V OE).} It referred to the period T ₃ the rated exciting period, a period for maintaining the excited state while supplying power near rated power of the lifting magnet 10. The excitation voltages V _OS and V _OE are controlled to the magnitude set in the initial power setting step S1 described above, that is, the magnitude corresponding to the maximum load of the suspended load. The exciting voltage V _RA, in the initial period T _3, is controlled magnitude is set by the initial power setting step S1 described above, that is, the magnitude V _RA1 corresponding to the maximum load of the suspended load.

  Subsequently, the lifting magnet control system proceeds to the power control step S4. In step S4, when the first control mode is selected in step S1, the signal processing unit 42 executes the following power adjustment steps S5 and S6. First, the signal processing unit 42 detects the mass of the suspended load suspended at that time based on the signal provided from the load cell 20 (step S5). Then, when the mass of the suspended load is smaller than the maximum load set in step S1, the signal processing unit 42 is configured so that the power supplied to the lifting magnet 10 has a magnitude corresponding to the current mass of the suspended load. Then, the applied voltage and / or supply current to the lifting magnet 10 are set again (step S6).

Here, Table 2 is a table showing an example of a reset value of the rated excitation voltage V _RA and release voltage V _RE used in the step S6, and the set value is predetermined in accordance with the detected weight of the suspended load Yes. Data including the contents of Table 2, that is, data in which the detected mass of the suspended load is associated with the magnitudes of the excitation voltage and the release voltage are stored in, for example, storage means (memory) included in the signal processing unit 42. Then, reset values of the voltages V _RA and V _RE corresponding to the detected mass of the suspended load are selected based on the data and sent to the control unit 33 as setting input information D1 (see FIG. 2). Based on this setting input information D1, the control unit 33 reduces the rated voltage V _RA and the release voltage V _RE to the lifting magnet 10 to a magnitude (V _RA2 , V _RE2 ) corresponding to the detected mass of the suspended load ( Step S7).

  If the mass of the suspended load detected in step S5 is equal to or greater than the maximum load, the signal processing unit 42 resets the applied voltage and supply current to the lifting magnet 10 in step S6. Rather, the initially set applied voltage and supply current are maintained.

When the second control mode is selected in step S1, the signal processing unit 42 does not execute steps S5 and S6 described above. At this time, the control unit 33 maintains the electric power supplied to the lifting magnet 10 at the initially set magnitude regardless of the mass of the suspended load. More specifically, as shown by a chain line in FIG. 5 (a), to maintain the excitation voltage _{V RA1} in the period _{T 3,} to maintain the release voltage _{V RE1} in the period _{T 4.}

Subsequently, the operation proceeds to release (release) the iron pieces from the lifting magnet 10. When the other switch 52 of the magnet operating unit 5 (or 51) the operator presses (step S8: time _t 2 shown in FIG. 5), the control unit 33 starts the demagnetization of the lifting magnet 10. That is, the bridge driver 32 that has received an instruction from the control unit 33 turns off the transistors 37a and 37d of the H bridge circuit unit 37 and turns on the transistors 37b and 37c. Thus, the direction is inverted current of the lifting magnet 10, it flows release current _{I 2} (step S9: the period _T 4 shown in FIG. 5). The release voltage at this time is set to the magnitude V _RE2 (<V _RE1 ) corresponding to the detected mass of the suspended load in the first control mode, and is set to the initial set value V _RE1 in the second control mode. The Thereby, the lifting magnet 10 and the suspended load are demagnetized, and the suspended load is released. Control unit 33, after the release current I ₂ flows, and non-conductive transistors 37b and 37c of the H-bridge circuit portion 37, showing the transistors 37a and 37d for power regeneration (FIG. 5 After conducting predetermined time period _T 5), and stops power supply to all of the transistors 37a~37d made nonconductive.

  In the lifting magnet control system and the lifting magnet control method described above, the power supplied to the lifting magnet 10 is reduced to a size corresponding to the mass of the lifting load G while the lifting load G is suspended from the lifting magnet 10. I am letting. Thereby, when the suspended load G is light with respect to the attracting force of the lifting magnet 10, the attracting force can be reduced to a necessary and sufficient level, and excessive power consumption can be suppressed. Further, since the magnitude of the power supplied to the lifting magnet 10 is made to correspond to the mass of the suspended load G, a part of the suspended load is raised each time the suspended load G is lifted, unlike the method described in Patent Document 1. Therefore, it is possible to maintain the working efficiency suitably.

  Further, as in the present embodiment, it is preferable to reduce the supply power according to data in which the mass of the suspended load G is associated with at least one of the current and voltage in the supply power. Thereby, the magnitude of the power supplied to the lifting magnet 10 (current and / or voltage) can be easily determined according to the data.

  Moreover, when the mass of the suspended load G detected by the load meter 20 is larger than a predetermined maximum load as in the present embodiment, the magnitude of the supplied power may be maintained. Thereby, even when the suspended load G has a large mass, the work can be performed safely without dropping a part of the suspended load G.

  In addition, the lifting magnet control system and the lifting magnet control method are the same as those in the first embodiment in the first control mode (when the mass of the suspended load G detected by the load meter 20 is smaller than the predetermined maximum load) And a second control mode (maintaining the supplied power at a preset size regardless of the mass of the suspended load G). Accordingly, the power consumption is reduced by reducing the power supply according to the mass of the suspended load G (first control mode), or the power supply is fixed to a size corresponding to the target mass of the suspended load G. Two work methods such as work (second control mode) can be suitably used according to the scene. In particular, by having the second mode, it is easy for the operator himself to limit the amount of suspended loads to be carried at one time, and the work can be performed safely even in places where the work space is limited.

  The lifting magnet control system and the lifting magnet control method according to the present invention are not limited to the above-described embodiments, and various other modifications are possible. For example, in the above embodiment, the first control mode in which the power supplied to the lifting magnet is reduced to a size corresponding to the mass of the suspended load, and the second that maintains the supplied power at the initial setting value regardless of the mass of the suspended load. However, the lifting magnet control system and the lifting magnet control method according to the present invention may have only the first control mode.

  In the above embodiment, the signal processing unit of the input device has a function of setting / adjusting the power supplied to the lifting magnet, but this function is provided by other devices (such as the control unit of the magnet control device). May be.

  In the above embodiment, a wired serial communication circuit is exemplified as a communication means between the input device and the magnet control device. However, the communication means may be wireless or an analog signal line indicating transmission information in voltage or the like. In addition to the touch panel described above, various means such as an adjustment knob, a switch, or a memory card reading device storing each set value can be applied as the input device.

It is a perspective view which shows the structure of the lifting magnet vehicle which is a working machine as an example of the mounting object of a lifting magnet control system. It is a block diagram which shows the structure of one Embodiment of the lifting magnet control system mounted in the lifting magnet vehicle shown in FIG. It is a circuit diagram which shows the structure of a magnet drive circuit. It is a flowchart which shows one Embodiment of the lifting magnet control method. (A) It is a graph which shows the time waveform of the voltage applied to the both ends of a lifting magnet. (B) It is a graph which shows the time waveform of the electric current supplied to a lifting magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lifting magnet vehicle, 2 ... Lifting magnet control system, 3 ... Magnet control apparatus (magnet control panel), 4 ... Input device, 5 ... Magnet operation part, 10 ... Lifting magnet, 12 ... Arm, 14 ... Driver's cab, 20 DESCRIPTION OF SYMBOLS ... Load meter, 31 ... Magnet drive circuit, 32 ... Bridge driver, 33 ... Control part, 34, 43 ... Serial communication circuit, 36 ... DC conversion part, 37 ... Bridge circuit part, 39 ... Current measurement part, 41 ... Touch panel, 42: signal processing unit, 51, 52: switch, ACG: three-phase AC power supply, G: suspended load, I ₁ ... excitation current, I ₂ ... release current.

Claims (8)

A magnet drive circuit for supplying power to the lifting magnet;
A control unit for controlling the magnitude of the power;
A mass detecting means for detecting a mass of the suspended load in a state where the suspended load is suspended from the lifting magnet;
When the mass of the suspended load detected by the mass detection unit is smaller than a predetermined value, the control unit reduces the electric power to a magnitude corresponding to the mass. Storage means for storing data in which the mass of the suspended load is associated with at least one of the current and voltage in the electric power;
The lifting magnet control system according to claim 1, wherein the control unit reduces the power according to the data of the storage unit.   3. The lifting according to claim 1, wherein the control unit maintains the magnitude of the electric power when the mass of the suspended load detected by the mass detection unit is larger than the predetermined value. 4. Magnet control system.   A first control mode for reducing the electric power to a magnitude corresponding to the mass when the mass of the suspended load detected by the mass detector is smaller than the predetermined value; and regardless of the mass of the suspended load, The lifting magnet control system according to any one of claims 1 to 3, further comprising a second control mode for maintaining electric power at an initially set magnitude. A method for controlling the amount of power supplied to a lifting magnet,
An initial power supply step of supplying the lifting magnet with the power of a preset magnitude;
A power adjustment step of reducing the power to a magnitude corresponding to the mass when the mass of the suspended load is smaller than a predetermined value in a state where the suspended load is attracted to and suspended from the lifting magnet. A lifting magnet control method.   In the power adjustment step, the power is reduced according to data in which a mass of the suspended load is associated with at least one of a current and a voltage in the power. The lifting magnet control method described.   7. The lifting magnet control method according to claim 5, wherein the magnitude of the electric power is maintained when the mass of the suspended load is larger than the predetermined value during the electric power adjustment step. 8. A method for controlling the amount of power supplied to a lifting magnet,
An initial power supply step of supplying the lifting magnet with the power of a preset magnitude;
A first control mode in which the electric power is reduced to a magnitude corresponding to the mass when the mass of the suspended load is smaller than the predetermined value, and the electric power is initially set regardless of the mass of the suspended load; And a power control step of executing any one of the second control modes to be maintained in accordance with an operator's selection.

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