JP6256423B2 - Engine control device for work machines - Google Patents

Description

  The present invention relates to an engine control device for a work machine including a lifting magnet.

  In a working machine equipped with a lifting magnet (hereinafter referred to as a lift magnet), when the direct current flowing through the magnet is stopped to release the lifting magnet (hereinafter referred to as a magnet), the energy by the back electromotive force (discharging power) Will occur. As a technique for consuming this discharge power, there is one described in Patent Document 1 below. The prior art is configured as follows.

  A magnet drive circuit described in Patent Document 1 that is a circuit of an inverter that outputs DC power to a magnet includes an energy absorption unit together with a DC conversion unit that converts an AC power supply voltage into a DC power supply voltage. The energy absorption unit is a resistance element. Have This resistance element consumes the discharge power.

JP 2007-119160 A

  As described in Patent Document 1, when an energy absorption unit having a resistance element is added to an inverter, the inverter becomes larger by that amount, and a large space for mounting the inverter must be secured in the work machine. Moreover, since the energy absorption part which has a resistance element is comparatively expensive, adoption of the inverter which has the said energy absorption part invites the cost increase of a working machine.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a riff magnet capable of effectively consuming the discharge power generated at the time of releasing the magnet without having an energy absorbing portion using a resistance element. It is to provide an engine control device for a machine.

  The present invention includes an engine, a generator motor connected to the engine and having a generator action and a motor action, an inverter that converts AC power generated by the generator motor into DC power, and outputs DC power, An engine control device for a work machine including a lifting magnet to which direct current power is supplied from an inverter. The engine control device includes a main body control device connected to the inverter, and a power holding circuit connected to the main body control device and supplying a power supply voltage to the engine and the inverter. The main body control device is configured so that when the engine is stopped while the engine is driven, the power holding circuit maintains a state in which the power supply voltage is supplied to the engine and the inverter if the lifting magnet is on the suction side. It is configured.

According to the present invention, when the magnet (lifting magnet) is released during the operation of the engine, the release discharge force generated thereby is consumed as regenerative energy by the generator motor connected to the engine. In addition, when the engine is stopped while the magnet is in the attracted state, the engine does not stop. Therefore, the release / discharge force generated when the magnet is released is consumed by the generator motor connected to the engine as regenerative energy in the same manner as described above. The
As described above, according to the present invention, the release / discharging force generated when the magnet is released can be effectively consumed without having the energy absorbing portion using the resistance element.

It is a block diagram which shows the control structure of the engine which concerns on one Embodiment of this invention. It is a flowchart which shows the control flow which concerns on one Embodiment of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that, as described above, the present invention relates to an engine control device for a work machine including a lifting magnet. A working machine including a lifting magnet is, for example, a handling machine (also referred to as a lifting mag machine) described in Japanese Patent Application Laid-Open No. 2007-45615.

(Equipment configuration around the engine control unit)
As shown in FIG. 1, a generator motor 2 having a generator action and a motor action is connected to an engine 1 (for example, a diesel engine) of a riff mag machine. AC power generated by the generator motor 2 by the driving force of the engine 1 is converted into DC power by the inverter 3. DC power is supplied from the inverter 3 to the magnet 4 (lifting magnet). By exciting the magnet 4 with DC power, the magnetic waste can be adsorbed by the magnet 4. Although depending on the work conditions, the time from the start of magnet 4 excitation to release is, for example, about 20 seconds per work.

  An engine control device according to an embodiment of the present invention includes a controller 5 as a main body control device connected to an inverter 3, a power holding circuit 12 connected to the controller 5, and a cluster gauge 6 (indicator) as notification means. ). The power supply holding circuit 12 is a circuit for supplying the power supply voltage from the 24V power supply 8 to the engine 1 and the inverter 3. In this embodiment, the power supply holding circuit 12 includes a battery relay 9, a power supply holding relay 10, and an engine holding relay 11. Is done. The contacts of the relays 9, 10, 11 are switched ON / OFF by a signal from the controller 5.

(When the engine is running)
First, the consumption of the release discharge force generated when releasing the magnet while the engine 1 is operating will be described. When the magnet 4 is in the attracting state, a direct current flows in the magnet 4. When the magnet 4 is released, that is, when the direct current flowing through the magnet 4 is stopped, energy (discharging power) due to the counter electromotive force is generated. While the engine 1 is in operation, this release / discharge force is consumed as regenerative energy by the generator motor 2 (the generator motor 2 acts as a motor).

(When the engine is stopped)
The consumption of the discharge power when the engine is stopped will be described with reference to FIG. As a premise, when the engine 1 is started by operating the key SW7, the battery relay 9, the power holding relay 10, and the engine holding relay 11 are all turned on, and the relays 9, 10 are operated during the engine operation. , 11 are in an ON state.

  Here, when the key SW7 is turned off, that is, when the engine stop operation is performed (YES in Step 1 (S1)), if the magnet 4 is not on the attracting side (NO in Step 2 (S2)), the controller 5 The engine holding relay 11 is turned off (step 3 (S3)), and the power holding relay 10 and the battery relay 9 are turned off (step 4 (S4)). As a result, the engine 1 stops and the riffmag machine stops completely.

  On the other hand, if the magnet 4 is on the attracting side (YES in step 2 (S2)), the controller 5 maintains the battery relay 9, the power holding relay 10, and the engine holding relay 11 all turned on (step 5 ( S5)). In other words, the controller 5 does not turn off the relays 9, 10, and 11. The controller 5 determines whether the magnet 4 is on the suction side or the non-attraction side based on the presence or absence of a suction signal transmitted from the inverter 3 to the controller 5. Since the supply of the power supply voltage to the engine 1 and the inverter 3 is maintained by the above step 3, the engine 1 does not stop and continues to operate.

  Then, the controller 5 displays on the cluster gauge 6 that the magnet 4 is in the attracted state (display of warning screen, step 6 (S6)). At this time, in addition to displaying a warning screen, it is also preferable to sound a warning sound informing that the magnet 4 is in the attracted state. The function of sounding a warning sound may be built in the cluster gauge 6 or may be controlled by the controller 5 by providing a speaker separately.

  If the magnet 4 is not released (NO in step 7 (S7)), the warning display is continued (step 6 (S6)). If the magnet 4 is released (YES in step 7 (S7)), the magnet 4 is released. When the predetermined time t has elapsed (step 8 (S8)), the controller 5 turns off the engine holding relay 11 (step 3 (S3)), and turns off the power holding relay 10 and the battery relay 9 (step 4). (S4)). As a result, the engine 1 stops and the riffmag machine stops completely. Whether or not the magnet 4 has been released is determined by the controller 5 based on the presence or absence of an adsorption signal transmitted from the inverter 3 to the controller 5.

  Since the engine 1 continues to operate when the magnet 4 is released as described above, the release / discharge force generated when the magnet is released is consumed by the generator motor 2 as regenerative energy (the generator motor 2 acts as a motor). If the key SW7 is turned OFF and the engine 1 is stopped when the magnet 4 is in the attracted state, the DC current flowing in the magnet 4 loses the place where it is consumed and flows into the inverter 3 to cause overvoltage. • Overcurrent will occur and inverter 3 will be damaged.

(Function and effect)
According to the present invention, when the magnet (lifting magnet) is released during the operation of the engine, the release discharge force generated thereby is consumed as regenerative energy by the generator motor connected to the engine. In addition, when the engine is stopped while the magnet is in the attracted state, the engine does not stop. Therefore, the release / discharge force generated when the magnet is released is consumed by the generator motor connected to the engine as regenerative energy in the same manner as described above. The As described above, according to the present invention, the release / discharging force generated when the magnet is released can be effectively consumed without having the energy absorbing portion using the resistance element.

In the present invention, as described above, when an engine stop operation is performed while the engine is being driven, after a predetermined time (t seconds) has elapsed since the magnet 4 on the attracting side has returned to the non-sucking side, It is preferable that the controller 5 controls the power holding circuit 12 so as to stop the supply of the power supply voltage to 1 and the inverter 3.
It is also possible to provide a current sensor for detecting an output current to the magnet 4 and input a signal from the current sensor to the controller 5 to determine that the magnet 4 has returned to the non-adsorption side based on a decrease in the current value. In this case, it is necessary to add a current sensor, which is disadvantageous in terms of cost. Since the time from the release of the magnet 4 to the non-adsorption state (the state in which the DC power is sufficiently reduced) can be predicted in advance, the time having a little margin in the predicted time is set as the predetermined time. If the time (t seconds) is set, the engine 1 is stopped after the discharge power is consumed. That is, according to the above configuration, it is possible to stop the engine after consuming the discharge power without adding a current sensor or the like.

Further, in the present invention, as described above, it is preferable that the controller 5 determines whether the magnet 4 is on the suction side or the non-attraction side based on the suction signal transmitted from the inverter 3. .
The controller 5 is originally connected to the inverter 3 in order to control the inverter 3. Therefore, it is easy to input a signal from the inverter 3 to the controller 5. As described above, whether the magnet 4 is on the attracting side or the non-attracting side can be determined by a signal from a separately provided current sensor. However, according to the above configuration, the current sensor is provided separately. This is advantageous in terms of cost because it is not necessary.

Further, in the present invention, as described above, when the engine is stopped while the engine is being driven, if the magnet 4 is on the suction side, notification means for notifying that the magnet 4 is on the suction side (in the above example, the cluster gauge 6 ) Is preferably provided.
When the operator performs an engine stop operation, if the magnet 4 is on the attracting side, the engine 1 does not stop against the operator's intention to stop the engine. According to the above configuration, it is possible to notify the operator that the magnet 4 is on the suction side (can notify that the engine 1 does not stop because the magnet 4 is on the suction side). Therefore, it is possible to prevent an unnecessary operation of the operator due to the engine 1 not being stopped, and it is possible to prevent a malfunction of the device due to the operator performing an unnecessary operation.

(Modification)
The above embodiment can be modified as follows.
Instead of the controller 5 determining whether the magnet 4 is on the attracting side or the non-attracting side based on the attracting signal transmitted from the inverter 3 to the controller 5, a signal related to whether or not the magnet 4 is released is used. The signal may be input to the controller 5, and the controller 5 may determine whether the magnet 4 is on the attracting side or the non-sucking side based on this signal.

  As described above, instead of the control for stopping the supply of the power supply voltage to the engine 1 and the inverter 3 after a predetermined time (t seconds) has elapsed after the magnet 4 that has been on the attracting side has returned to the non-attracting side. A current sensor for detecting the output current to the magnet 4 may be provided, and control for stopping the supply of the power supply voltage to the engine 1 and the inverter 3 may be performed based on a signal from the current sensor.

  In addition, it is needless to say that various modifications can be made within a range that can be assumed by those skilled in the art.

1: Engine 2: Generator motor 3: Inverter 4: Magnet (lifting magnet)
5: Controller (main body control device)
6: Cluster gauge (display, notification means)
9: Battery relay 10: Power holding relay 11: Engine holding relay 12: Power holding circuit

Claims (4)

An engine, a generator motor connected to the engine and having a generator action and a motor action; an inverter that converts AC power generated by the generator motor into DC power; and outputs DC power; and DC power from the inverter A lifting magnet to be supplied with an engine control device for a work machine,
A main body control device connected to the inverter;
A power holding circuit connected to the main body control device for supplying a power voltage to the engine and the inverter;
With
When the main body control device is operated to stop the engine while the engine is operating, the power holding circuit maintains the state in which the power supply voltage is supplied to the engine and the inverter if the lifting magnet is on the attracting side. by being configured, without stopping the engine, the release power generated during release of the lifting magnet, characterized thereby consumed by the generator motor as a regenerative energy, work machine of the engine control device. The engine control device for a work machine according to claim 1,
When the engine control operation is performed while the engine is being driven, the main body control device is configured to supply power to the engine and the inverter after a predetermined time has elapsed since the lifting magnet that was on the suction side returns to the non-attraction side. Configured to control the power holding circuit to stop the supply of voltage;
An engine control device for a work machine. The engine control device for a work machine according to claim 1 or 2,
The main body control device receives an adsorption signal transmitted from the inverter,
The main body control device is configured to determine from the adsorption signal whether the lifting magnet is on the adsorption side or the non-adsorption side.
An engine control device for a work machine. In the engine control apparatus of the working machine according to any one of claims 1 to 3,
When an engine stop operation is performed during engine driving, if the lifting magnet is on the suction side, further provided is a notification means for notifying that it is on the suction side.
An engine control device for a work machine.

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