JP4207630B2 - Self-propelled lifting magnet work machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a self-propelled lifting magnet working machine that performs operations such as sorting and loading of metal scrap such as iron with a lifting magnet attached to the tip of an arm.
[0002]
[Prior art]
In general, this type of self-propelled lifting magnet working machine includes an engine-driven hydraulic pump, a hydraulic motor driven by oil discharged from the hydraulic pump, and the hydraulic motor, as disclosed in, for example, Patent Document 1 A generator driven by the arm and a lifting magnet attached to the end of the arm and using the generator as a power source, and controlling the energization from the generator to the lifting magnet to attract and release metal scrap by the lifting magnet It has become.
[0003]
By the way, in a self-propelled lifting magnet working machine, a failure may occur during the adsorption of metal scrap by the lifting magnet, which may hinder the energization of the lifting magnet. Conventionally, as a countermeasure against such a failure, for example, as disclosed in Patent Document 2, two energization circuits in which an electromagnetic coil, a circuit breaker, and a current relay are arranged in series with respect to one power source are disclosed. It is known that the voltage applied to the electromagnetic coil in the other energizing circuit is doubled to the rated voltage when a failure occurs in one energizing circuit to prevent the adsorbed material from dropping when connected in parallel. . Patent Document 3 discloses that a permanent electromagnetic electromagnet is used as a lifting magnet so that the adsorbed material can be prevented from falling even if the lifting magnet cannot be energized due to a failure.
[0004]
[Patent Document 1]
Japanese Utility Model Publication No. 57-99882 (all pages, all figures)
[Patent Document 2]
JP-A-6-227785 (page 2-3, FIG. 1)
[Patent Document 3]
Japanese Patent Laid-Open No. 9-240980 (page 2-6, FIGS. 1 to 4)
[0005]
[Problems to be solved by the invention]
However, among the above-mentioned conventional countermeasures against failure, the former one requires the provision of two energization circuits, which causes problems such as a complicated circuit configuration and high cost. On the other hand, the latter has a problem that the adsorbate cannot be dropped even after moving to a safe place, which is insufficient for ensuring safety.
[0006]
In addition, all of the above conventional countermeasures are taken from the viewpoint of preventing the adsorbate from falling, but when the fault is a serious problem such as overcurrent or overvoltage, the expansion of the fault or the occurrence of a fire is prevented. In order to prevent this, it is desirable to immediately stop energization of the lifting magnet, and this point is not considered at all.
[0007]
The present invention has been made in view of such various points, and the problem is that when a failure occurs during the adsorption of metal scrap by the lifting magnet, the safety is ensured by appropriately dealing with the state of the failure. It is intended to provide a self-propelled lifting magnet working machine that can be sufficiently improved and can be implemented at low cost.
[0008]
[Means for achieving the object]
In order to achieve the above object, the invention according to claim 1 is directed to a self-propelled lifting magnet working machine in which a lifting magnet powered by a hydraulic motor-driven generator is attached to the tip of an arm. Control means for controlling energization to the magnet is provided. In this control means, a failure is detected based on signals from various detection means during energization of the lifting magnet, and at the same time, the failure is a minor failure that allows the energization of the lifting magnet to continue, or a fault that cannot be continued. If it is a serious failure, it immediately stops energization of the lifting magnet and disables re-adsorption. Then, a configuration is adopted in which energization is stopped and re-adsorption is disabled.
[0009]
In this configuration, when a failure occurs during energization of the lifting magnet, that is, during metal scrap adsorption, the control means not only detects the failure based on signals from various detection means, but also the failure is transferred to the lifting magnet. It is determined whether it is a minor failure that can be energized continuously, or a major failure that cannot be continued.In the case of a major failure, the energization of the lifting magnet is immediately stopped and re-adsorption is disabled. The energization of the lifting magnet is continued until the release operation is performed, and then the energization is stopped and the re-adsorption is disabled. In addition, the adsorbate can be released in a safe place while preventing the adsorbate from dropping in the event of a minor failure. Here, the various detection means detect at least an output current to the lifting magnet, an output voltage to the lifting magnet, and a battery power supply voltage, and the control means has an output current to the lifting magnet of a predetermined value or more. An overcurrent, a short circuit in which the load resistance of the lifting magnet becomes minute, an overvoltage at which the output voltage to the lifting magnet exceeds a predetermined value, and a second predetermined value in which the battery power supply voltage is smaller than the first predetermined value A serious power supply voltage drop that falls to the following is determined as a serious failure, the output voltage drop when the output voltage to the lifting magnet becomes a predetermined value or less, and the battery power supply voltage is a first predetermined value and a second predetermined value. It is preferable that a slight power supply voltage drop that falls between the two is determined as a minor failure.
[0010]
According to a second aspect of the present invention, in the self-propelled lifting magnet working machine according to the first aspect of the present invention, the self-propelled lifting magnet working machine is provided with a reset switch for releasing the state where the re-adsorption is disabled. When it is a thing, it is comprised so that a non-re-adsorptive state may be canceled automatically regardless of the operation of the reset switch. In this configuration, not only can the operator be encouraged to investigate the cause of the failure until the operator operates the reset switch to release the non-resorbable state, but also controls when the failure is temporary, such as overheating. Since the non-resorbable state is automatically released by the means, the labor of the operator can be saved.
[0011]
The invention according to claim 3 is the self-propelled lifting magnet working machine according to claim 2, further comprising notifying means for notifying the operator when the control means detects a failure. Is configured so as to perform a notification operation until the non-resorbable state is released. In this configuration, when a failure occurs during the adsorption of the metal scrap by the lifting magnet, the notification unit performs a notification operation based on the failure detection of the control unit, so that the operator can recognize the occurrence of the failure. In addition, since the notification operation of the notification means continues until the non-resorbable state is canceled, it is possible to more reliably prompt the operator to investigate the cause of the failure by operating the reset switch.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an external appearance of a self-propelled lifting magnet working machine according to an embodiment of the present invention. 1 is a lower traveling body having a crawler, and 2 is provided on the lower traveling body 1 so as to be able to turn. The upper swing body 2 is equipped with an engine 20 (see FIG. 2) at the rear of the upper swing body 2, and the cabin 3 is vertically moved along the inclined surface 4 at the front of the upper swing body 2. It is provided to be movable.
[0014]
In addition, the base end of the boom 5 is connected to the upper swing body 2 via a support shaft 6, and the base end of an arm 7 is connected to the tip of the boom 5 via a support shaft 8. A lifting magnet 10 is attached to the tip of the arm 7 via a support shaft 9 or the like. The boom 5 swings up and down around the support shaft 6 by a hydraulic cylinder 11, and the arm 7 and the lifting magnet 10 rotate around the support shafts 8 and 9 by hydraulic cylinders 12 and 13, respectively. ing. The lifting magnet 10 adsorbs metal scrap such as iron and performs operations such as sorting and loading.
[0015]
FIG. 2 shows a schematic configuration of a hydraulic / electric system of the self-propelled lifting magnet working machine. Reference numeral 20 denotes an engine mounted on the upper swing body 2, and the engine 20 includes a plurality (three in the figure) of hydraulic pressure. The pumps 21, 22, and 23 are driven. One of the hydraulic pumps 23 drives the hydraulic motor 25 for the generator 24 by the discharged oil, and the discharged oil of the other hydraulic pumps 21 and 22 is another actuator of the work machine, that is, The hydraulic cylinders 11 to 13 for driving the boom 5 and the arm 7 and the circuit of the hydraulic motor are supplied.
[0016]
The generator 24 is driven by a hydraulic motor 25 to generate power, and supplies power to the lifting magnet 10 as its power source. A control panel 30 is electrically connected between the generator 24 and the lifting magnet 10 as control means for controlling energization from the generator 24 to the lifting magnet 10. The control panel 30 is connected to the lifting magnet 10. 10 includes a voltage control circuit 31 that variably controls the output voltage to 10 and a control command circuit 32 that outputs and controls a control command to the voltage control circuit 31.
[0017]
The voltage control circuit 31 includes a constant voltage circuit 33 and a polarity switching circuit 34 as shown in FIG. The constant voltage circuit 33 further includes a full wave rectifier circuit 36, a voltage control switch circuit 37, a smoothing circuit 38, and a voltage sensor 39. The full-wave rectifier circuit 36 outputs the three-phase output of the generator 24 between the rectifiers of three full-wave rectifiers each formed by serially connecting two rectifier elements 36a, 36b, 36c, 36d or 36e, 36f such as diodes. These are connected in parallel, and the full-wave rectifiers are connected in parallel with the same polarity. The voltage control switch circuit 37 short-circuits or opens both poles of the full-wave rectifier circuit 36, and includes a semiconductor switching element 37a made of a transistor or the like. Thereby, a step-up chopper using the leakage inductance of the generator 24 is possible. The voltage appearing in the smoothing circuit 38 can be changed by changing the time ratio of the short circuit or the open circuit of the voltage control switch circuit 37. The smoothing circuit 38 includes a diode 38a that prevents backflow and a capacitor 38b that absorbs a voltage change caused by switching. One end of the capacitor 38b is connected to the positive electrode of the full-wave rectifier circuit 36 through the diode 38a in the forward direction. The other end of the capacitor 38b is connected to the negative electrode of the full-wave rectifier circuit 36. The voltage sensor 39 is provided in parallel with the capacitor 38b so as to detect the voltage of the smoothing circuit 38.
[0018]
The polarity switching circuit 34 connects the positive and negative poles of the smoothing circuit 38 and the two load terminals 41 and 42 in a crossed manner, and between the positive electrode of the smoothing circuit 38 and the load terminal 41 and Two forward switch circuits 34a and 34b for short-circuiting or opening between the negative electrode of the smoothing circuit 38 and the load terminal 42, between the positive electrode of the smoothing circuit 38 and the load terminal 42, and of the smoothing circuit 38 It consists of two reverse direction switch circuits 34c and 34d for short-circuiting or opening between the negative electrode and the load terminal 41. A bypass switch circuit 43 and a power consumption resistor 44 are inserted in series between the two load terminals 41 and 42. A current sensor 45 as a detecting means for detecting an input / output current from the smoothing circuit 38, that is, a current of the generator 24, is provided on either the positive or negative pole (negative electrode in the drawing) of the smoothing circuit 38. Each of the switch circuits 34a to 34d, 43 is composed of a semiconductor switching element made of a transistor or the like. And the electrode of the voltage applied to the electromagnetic coil 46 of the lifting magnet 10 is reversed by switching the short circuit / open circuit between the forward switch circuits 34a, 34b and the reverse switch circuits 34c, 34d of the polarity switching circuit 34. . The bypass switch circuit 43 is closed when the voltage between both ends of the electromagnetic coil 46 becomes a predetermined voltage or higher due to the reverse flow of power generated in the electromagnetic coil 46 at the start of releasing the scrap by the lifting magnet 10. The power is consumed by short-circuiting the both ends of the coil 46 with the resistor 44.
[0019]
On the other hand, the control command circuit 32 is constituted by a microcomputer incorporating a CPU, a memory and the like, and signals from the voltage sensor 39 and the current sensor 45 of the voltage control circuit 31 are input to the control command circuit 32. In addition, signals such as an adsorption / release switch 51, a reset switch 52, and a temperature sensor 53 are also input. The temperature sensor 53 measures the temperature of the cooling fin of the control panel 30. A 28 V power supply battery 54 is connected to the control command circuit 32. Although not shown, the control command circuit 32 has a built-in voltage sensor for measuring the voltage of the power supply battery 54, and the signal of this sensor is also input. Is done. The control command circuit 32 is connected to an abnormality display lamp 55 as a notification means for visually notifying the operator of a failure of the work machine. The abnormality display lamp 55 is connected to the operator in the cabin 3. It is provided in a place where it is easy to see.
[0020]
The control command circuit 32 controls the time ratio of the short circuit or the open circuit of the switching element 37a of the voltage control switch circuit 37 according to the comparison between the output voltage of the smoothing circuit 38 detected by the voltage sensor 39 and the target voltage. Thus, a step-up chopper using the leakage inductance of the generator 24 is configured to achieve constant voltage control. The control command circuit 32 controls short-circuiting or opening of the switch circuits 34a to 34d of the polarity switching circuit 34 based on the signal from the adsorption / release switch 51, and performs failure determination control. The control is performed according to the flowchart shown in FIG.
[0021]
That is, in FIG. 4, the operation starts when the operator operates the engine key from OFF to ON. First, initial setting is performed in step S1. In this initial setting, energization (also referred to as magnet output) to the electromagnetic coil 46 of the lifting magnet 10 is turned off (OFF state), and a failure flag F described later is set to zero.
[0022]
Subsequently, in step S2, it is determined whether or not the adsorption / release switch 51 has been changed from OFF to ON by the operator's operation. If the determination is YES, whether or not the current magnet output is OFF in step S3. Determine whether. When this determination is NO, that is, when the current magnet output is on and metal scrap such as iron is being attracted to the lifting magnet 10, the magnet output is turned off in step S5 to release the adsorbate, while the determination is YES. In some cases, it is further determined in step S4 whether or not the failure flag F is “0”. If the determination is YES, the magnet output is turned on in step S6 to attract the metal scrap to the lifting magnet 10.
[0023]
When the determination in step S2 or S4 is NO, or when step S5 or S6 is executed, failure determination control is executed in step S7, and then the process returns to step S2. The above control is performed until the operator returns the engine key from on to off. The failure determination control is performed according to the flowchart shown in FIG. Hereinafter, this failure determination control will be described.
[0024]
In FIG. 5, first, in step S11, signals from various sensors 39, 45, 53 and switches 51, 52 are read, and then failure determination is performed in step S12. In this failure determination, a failure is detected based on the signals of the various sensors 39, 45, and 53, and at the same time, it is determined whether the failure is a minor failure that allows the magnet output to continue or a major failure that cannot continue. Specifically, detection and determination are performed as follows according to the type of failure.
(1) Overcurrent: A failure in which the output current to the electromagnetic coil 46 of the lifting magnet 10 becomes a predetermined value or more, and is detected based on the detection signal of the current sensor 45. Since the voltage control circuit 31 of the control panel 30 may be burned out, it is determined as a serious failure.
(2) Short-circuit: A failure in which the voltage control circuit 31, which is an output circuit to the electromagnetic coil 46 of the lifting magnet 10, is short-circuited and the load resistance becomes very small. Detect. Since the voltage control circuit 31 may be damaged in the same manner as in the case of an overcurrent, it is determined that there is a serious failure.
(3) Overvoltage: This is a failure in which the output voltage of the lifting magnet 10 to the electromagnetic coil 46 exceeds a predetermined value, and is detected based on the detection signal of the voltage sensor 39. As in the case of an overcurrent, the voltage control circuit 31 may be damaged or an electric shock accident at a high voltage may occur.
(4) Serious power supply voltage drop: A failure in which the voltage of the power supply battery 54 of the control command circuit 32 drops to a predetermined value (about 19 V) or less, and is detected based on a detection signal of a voltage sensor built in the control command circuit 32 To do. Since the control command circuit 32 may stop and the voltage control circuit 31 may become uncontrollable, it is determined that there is a serious failure.
(5) Output voltage drop: A failure in which the output voltage drops while the electromagnetic coil 46 of the lifting magnet 10 is energized (during adsorption), and is detected based on the detection signal of the voltage sensor 39. Since only the attractive force by the lifting magnet 10 is reduced, it is determined that there is a minor failure.
(6) Control panel temperature rise: A failure in which the temperature of the cooling fin of the control board 30 rises to a predetermined value or more, and is detected based on the detection signal of the temperature sensor 53. Since the temperature rise of the cooling fin is almost only temporary, it is determined as a minor failure.
(7) Minor power supply voltage drop: a failure in which the voltage of the power supply battery 54 of the control command circuit 32 drops to a predetermined value (about 20 V) or less, and is detected based on a detection signal of a voltage sensor built in the control command circuit 32 To do. The predetermined value (first predetermined value) at a slight power supply voltage drop is closer to the reference voltage (28V) than the predetermined value (second predetermined value) at a serious power supply voltage drop. Since the control command circuit 32 does not stop when the power supply voltage drops, it is determined that there is a minor failure.
[0025]
Subsequently, in step S13, it is determined whether or not there is a major failure, and in step S16, it is determined whether or not it is a minor failure. Then, when it is neither a major failure nor a minor failure, the failure determination control is terminated as it is. However, when it is a serious failure, it is determined whether or not the adsorption is being performed in step S14. If the determination is YES, the lifting magnet 10 is determined in step S15. The electromagnetic coil 46 is immediately de-energized to stop the suction, and the process proceeds to step S19. If the determination is NO, the process proceeds to step S19. If a minor failure occurs, it is determined in step S17 whether or not adsorption is in progress. If the determination is YES, in step S18, the energization state of the lifting magnet 10 to the electromagnetic coil 46 is maintained as it is and adsorption is continued. While the process proceeds to step S19, when the determination is NO, the process proceeds to step S19 as it is.
[0026]
In step S19, the failure flag F, which means the occurrence of a failure, is set to “1”, and the abnormality display lamp 55 is turned on. Thereafter, in step S20, it is determined whether or not the failure is temporary. In step S21, it is determined whether or not the reset switch 52 has been operated by the operator. The failure is temporary when, for example, the temperature of the control panel rises, which is one of the minor failures, and the temperature returns to the original value while the adsorption is continuing. If any one of the two determinations is YES, the failure flag F is set to “0” in step S22, the abnormality display lamp 55 is turned off, and the control is terminated. End control.
[0027]
Therefore, in such control, when a failure occurs during energization of the electromagnetic coil 46 of the lifting magnet 10, that is, during the adsorption of metal scrap such as iron by the lifting magnet 10, the various sensors 39, 45, and 53 A failure is detected based on the detection signal, and at the same time, it is determined whether the failure is a minor failure that can continue to energize the electromagnetic coil 46 of the lifting magnet 10 or a major failure that cannot be continued. If so, the suction is immediately stopped (step S15), and re-sucking is disabled by setting the failure flag F to “1” (steps S19 and S4). On the other hand, if the fault is minor, the operator performs a release operation. During this time, the adsorption is continued (steps S18, S3, S5), and then the energization is stopped to make the adsorption impossible. For this reason, it is possible to prevent the failure from spreading due to continued energization of the electromagnetic coil 46 of the lifting magnet 10 in the event of a major failure, the occurrence of a fire, etc., and in a safe place while preventing the adsorbate from dropping in the event of a minor failure. The adsorbate can be released, and the safety can be sufficiently improved.
[0028]
In addition, when the failure flag F becomes “1” due to the occurrence of a failure and the re-adsorption by the lifting magnet 10 becomes impossible, the operator normally does not operate the reset switch 52 provided on the control panel 30 or the like. The state cannot be released, and the operator can be prompted to investigate the cause of the failure until the set switch 52 is operated. Moreover, when the failure is temporary, the failure flag F is automatically set to “0” without being operated by the reset switch 52 (step S22), and re-adsorption by the lifting magnet 10 becomes possible. The user's trouble can be saved and the convenience can be enhanced.
[0029]
In addition, when a failure occurs, the abnormality display lamp 55 is turned on regardless of whether it is a major failure or a minor failure (step S19), so that the operator can recognize the fact and further improve safety. Can do. In addition, the lighting of the abnormality display lamp 55 continues until the non-resorbable state is released by the operation of the normal reset switch 52, so that the operator can prompt the investigation of the cause of the failure and the operation of the reset switch 52. Therefore, the safety can be further improved.
[0030]
In addition, this invention is not limited to the said embodiment, Other various embodiment is included. For example, in the above embodiment, the control panel temperature rise in which the temperature of the cooling fin of the control panel 30 rises to a predetermined value or more is regarded as a minor failure, but the present invention is such that the temperature of the control panel 30 is higher than the first predetermined value T1. A major failure is defined as a large second predetermined value T2 (> T1) or more, and a minor failure is defined when the temperature of the control panel 30 is between the first predetermined value T1 and the second predetermined value T2. You may make it do.
[0031]
Further, in the above embodiment, the control panel 30 as the control means for controlling the energization from the generator 24 to the lifting magnet 10 is configured to include the voltage control circuit 31 and the control command circuit 32. Both of the circuits 31 and 32 may be constituted by a single semiconductor integrated circuit. Furthermore, the voltage control circuit 31 may be configured using not only the constant voltage circuit 33 and the polarity switching circuit 34 as in the above embodiment but also using two forward and reverse thyristor rectifiers.
[0032]
【The invention's effect】
As described above, according to the self-propelled lifting magnet working machine of the present invention, when a failure occurs during the energization of the lifting magnet, the energization of the lifting magnet is immediately performed if there is a serious failure that cannot be energized. If it is a minor failure that can be energized, the energization of the lifting magnet is continued until the operator performs the release operation, and then energization is stopped to disable re-adsorption. Therefore, in the event of a major failure, it is possible to prevent the spread of failure due to continued energization and the occurrence of a fire, etc., and in the event of a minor failure, the adsorbate can be released in a safe location while preventing the adsorbate from falling. Can be sufficiently improved. In addition, it is not necessary to provide two energization circuits as in the prior art, and it can be implemented at low cost, which is advantageous for implementation.
[0033]
In particular, the invention according to claim 2 can not only prompt the operator to investigate the cause of the failure until the worker operates the reset switch to release the non-resorbable state, but the failure is temporary. In this case, since the non-re-suckable state is automatically canceled, it is possible to save the labor of the operator and improve the convenience.
[0034]
Further, in the invention according to claim 3, when the failure occurs while the lifting magnet is energized, the notification means starts the notification operation and continues the notification operation until the non-re-adsorptive state is released. In addition to recognizing the occurrence, it is possible to prompt the operator to investigate the cause of the failure and to further improve safety.
[Brief description of the drawings]
FIG. 1 is a side view showing an external appearance of a self-propelled lifting magnet working machine according to an embodiment of the present invention.
FIG. 2 is a block configuration diagram showing a schematic configuration of a hydraulic / electric system of the work machine.
FIG. 3 is an electric circuit diagram showing a configuration in the vicinity of the voltage control circuit of FIG. 2;
FIG. 4 is a flowchart showing the control contents of a control command circuit.
FIG. 5 is a flowchart of failure determination control.
[Explanation of symbols]
7 Arm 10 Lifting magnet 24 Generator 30 Control panel (control means)
31 Voltage control circuit 32 Control command circuit 39 Voltage sensor (detection means)
45 Current sensor (detection means)
46 Electromagnetic coil 52 Reset switch 55 Abnormal indicator lamp (notification means)

Claims (3)

In a self-propelled lifting magnet working machine in which a lifting magnet powered by a hydraulic motor-driven generator is attached to the tip of the arm,
Control means for controlling energization from the generator to the lifting magnet is provided. This control means detects a failure based on signals from various detection means when energizing the lifting magnet, and at the same time, the failure is lifted. It is determined whether the fault is a minor fault that can continue to energize the magnet or a major fault that cannot be continued. In the case of a major fault, the energization of the lifting magnet is immediately stopped to disable re-adsorption. It is provided to continue energization to the lifting magnet until the person performs the release operation, then stop energization and disable re-adsorption ,
The various detection means detect at least the output current to the lifting magnet, the output voltage to the lifting magnet, and the battery power supply voltage.
The control means includes an overcurrent in which the output current to the lifting magnet becomes a predetermined value or more, a short circuit in which the load resistance of the lifting magnet becomes minute, an overvoltage in which the output voltage to the lifting magnet exceeds a predetermined value, a battery power supply A serious power supply voltage drop in which the voltage drops to a second predetermined value or less that is smaller than the first predetermined value is determined as a serious failure, and an output voltage drop that causes the output voltage to the lifting magnet to be a predetermined value or less; Self-propelled lifting magnet operation characterized in that a slight power supply voltage drop that causes the battery power supply voltage to fall between a first predetermined value and a second predetermined value is determined as a minor failure. machine.   On the other hand, the control means includes a reset switch for releasing the state where the re-adsorption is disabled, and the control means automatically releases the non-re-adsorption state regardless of the operation of the reset switch when the failure is temporary. The self-propelled lifting magnet working machine according to claim 1.   When the control means detects a failure, the control means is provided with a notification means for notifying the operator of the failure, and the notification means is provided so as to perform a notification operation until the non-resorbable state is released. Item 3. A self-propelled lifting magnet working machine according to item 2.

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