Construction machinery

Abstract

To obtain construction machinery that can prevent low-voltage batteries from running out of power while the machine is idle. [Solution] The construction machine (2) of the present invention is characterized by having a disconnect switch (51) that switches between energized and disconnected states between a low-voltage battery (41) and a low-voltage device (61), and an external power supply circuit (81) that, when the disconnect switch is switched to the disconnected state, supplies power from the external power supply (34) to the low-voltage device when the external power supply (34) is connected.

Description

Technical Field

[0001] The present invention relates to a construction machine equipped with a power supply device.

Background Art

[0002] Construction machines such as mining dump trucks and mining shovels are equipped with a low-voltage battery for controlling and operating vehicle equipment and a high-voltage battery for driving a traveling motor or the like. When the construction machine is not starting the engine or the high-voltage battery, the low-voltage battery serves as the power source for low-voltage devices such as headlights, interior lights, horns, and radios. When starting the engine, the low-voltage battery also serves as the power source for the alternator, which is an auxiliary machine of the engine, and charging is also performed by driving the alternator. When starting the high-voltage battery, the power supplied from the high-voltage battery is voltage-converted by a DCDC converter to serve as the power source for low-voltage devices, and charging of the low-voltage battery is also performed.

[0003] However, if the construction machine is left unattended for a long time without starting the engine or the high-voltage battery, the low-voltage battery continues to consume power for maintaining the internal memory of the controller even when the key position of the key switch is in the key OFF state. Therefore, there is a risk of so-called power shortage where the voltage of the low-voltage battery rises. Patent Document 1 discloses a technique of providing a disconnect switch for disconnecting the low-voltage battery from the consumption circuit in a construction machine. By setting the disconnect switch to the OFF position when the construction machine is not in operation, it is possible to prevent power shortage of the low-voltage battery due to long-term storage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the disconnect switch is turned to the OFF position, all power supply from the low-voltage battery is cut off, making it impossible to use low-voltage equipment that relies on the low-voltage battery as a power source. For example, it becomes impossible to turn on headlights or interior lights in the pit area or parking area, honk the horn, or listen to the radio.

[0006] On the other hand, low-voltage equipment can be used by setting the disconnect switch to the ON position and the key switch to the ACC position, but in either case, prolonged use may deplete the low-voltage battery. Furthermore, when the key position is in the ON position, the controllers of each control device start up and communication between controllers begins, causing a dramatic increase in power consumption. Therefore, if the engine is not started or the high-voltage battery is not started in this state, the low-voltage battery will be depleted in a short time. In particular, battery-powered mining dump trucks have many electrical devices installed, and consequently, many controllers to control them, resulting in high power consumption and the risk of the low-voltage battery being depleted in a short time.

[0007] The present invention has been made in view of the above points, and its object is to provide a construction machine that can prevent a low-voltage battery from running out of power while the machine is idle. [Means for solving the problem]

[0008] The construction machine of the present invention, which solves the above problems, A construction machine equipped with low-voltage equipment powered by a low-voltage battery, A disconnect switch for switching between the energized state and the disconnected state of the low-voltage battery and the low-voltage equipment, When the disconnect switch is switched to the disconnected state, an external power supply circuit is activated, which supplies power from the external power supply to the low-voltage device when an external power supply is connected. It is characterized by having the following features. [Effects of the Invention]

[0009] According to the present invention, it is possible to obtain a construction machine that can prevent the low-voltage battery from running out of power while the machine is idle.

[0010] Further features related to the present invention will become apparent from the description herein and the accompanying drawings. Problems, configurations, and effects not described above will be revealed by the following description of embodiments. [Brief explanation of the drawing]

[0011] [Figure 1] Front view of a mining dump truck according to the first embodiment of the present invention. [Figure 2] A side view of a mining dump truck according to the first embodiment of the present invention. [Figure 3] A schematic circuit diagram of a mining dump truck according to the first embodiment of the present invention. [Figure 4] Low-voltage electrical circuit diagram of a mining dump truck in the first embodiment of the present invention. [Figure 5] Low-voltage electrical circuit diagram of a mining dump truck in a second embodiment of the present invention. [Figure 6] A reference example of a low-voltage electrical circuit diagram for the first embodiment of the present invention. [Modes for carrying out the invention]

[0012] The following describes embodiments to which the present invention is applied.

[0013] [First Embodiment] A first embodiment of the present invention will be described with reference to the drawings.

[0014] <Overall Structure> FIG. 1 is a front view of the mining dump truck in the first embodiment of the present invention, and FIG. 2 is a side view of the mining dump truck in the first embodiment of the present invention.

[0015] The mining dump truck 2 is equipped with a body 12 for loading a conveyance such as earth and sand on a frame 11, and both are connected by a hoist cylinder 13. Further, on the frame 11, a front wheel 14, a rear wheel 15, a hydraulic oil tank 16, a fuel tank 17, etc. are attached via mechanism parts not shown. A traveling motor 24 for driving the rear wheel 15 is housed in the rotating shaft part of the rear wheel 15.

[0016] At the front part of the vehicle of the frame 11, a cab 18 on which an operator rides to operate the mining dump truck 2 and a control cabinet 19 in which various electric devices are stored are mounted. And, on the upper front part of the cab 18, a pantograph 211 of a power receiving device 21 for contacting a trolley wire 31 (see FIG. 3) to receive DC power supply is equipped. The power receiving device 21 shows a state in which the pantograph 211 is folded in FIG. 1 and a state in which the pantograph 211 is extended in FIG. 2.

[0017] And, a power storage device (high voltage battery) 22 for storing and regenerating electric energy is mounted behind the cab 18 of the vehicle. Also, an engine, a main generator, an auxiliary generator, etc. are mounted in a part hidden by the front wheel 14 in FIG. 1.

[0018] FIG. 3 is a schematic circuit diagram of the mining dump truck 2. The mining dump truck 2 includes a power receiving device 21, a power storage device 22, a sensor 23, and, as high voltage devices, a traveling motor 24, an inverter 25, a DC / DC converter 26, a resistor 27, a chopper circuit 28, and a control device 29. Also, in the example shown in FIG. 3, the mining dump truck 2 includes a switch box SB and an accessory power device PD. Hereinafter, the configuration of each part of the mining dump truck 2 of the present embodiment will be described in detail.

[0019] The power receiving device 21 is a device that receives power supply from outside the mining dump truck 2. The power receiving device 21 includes at least one of, for example, a pantograph 211 and a charging port 212.

[0020] The pantograph 211 is provided on the upper part of the mining dump truck 2 and is configured to extend and contract vertically, for example, by the operation of an operator of the mining dump truck 2. By extending upward, the pantograph 211 contacts the trolley wire 31 of the power feeding device 3 and receives power supply from the trolley wire 31. As shown in FIG. 3, the pantograph 211 is connected to the traveling motor 24 via an inverter 25 and is connected to the power storage device 22 via a DC / DC converter 26, for example.

[0021] The charging port 212 is provided, for example, at a position below the front part of the mining dump truck 2. The charging port 212 is detachably connected to the charging cable 321 of the charging station 32. The charging port 212 is directly connected to the positive electrode terminal 221, which is one electrode terminal of the power storage device 22, and the negative electrode terminal 222, which is the other electrode terminal. The charging station 32 is installed at the pit work area or the parking area of the mining dump truck 2.

[0022] Hereinafter, with reference to FIG. 3, an electrical configuration related to the traveling drive of the mining dump truck 2 will be described. In FIG. 3, the solid lines connecting between the respective components are lines used for power supply, and the broken lines are signal lines used for communication.

[0023] The energy storage device 22 is electrically connected to the power receiving device 21 and is charged by power supplied from the power receiving device 21. The energy storage device 22 is also electrically connected to the traction motor 24 and is charged by regenerative power generated by the regenerative braking of the traction motor 24. The energy storage device 22 includes, for example, a plurality of single cells (high-voltage batteries) 223 connected in series and parallel. The type of single cell 223 is not particularly limited, but for example, lead-acid batteries or lithium-ion secondary batteries can be used.

[0024] Sensor 23 is used to estimate the charge level of the energy storage device 22. Sensor 23 detects the voltage of the stored energy storage device 22, the voltage received by the power receiving device 21, and the voltage regenerated by the traction motor 24. Sensor 23 includes, for example, a voltage sensor 231 that detects the voltage in the power supply path between the power receiving device 21 and the DC / DC converter 26.

[0025] The voltage sensor 231 is a sensor capable of detecting, for example, the power received by the power receiving device 21 and the regenerative voltage of the driving motor 24 when power that can be charged into the energy storage device 22 is generated by the power receiving device 21 or the driving motor 24 (i.e., when the power receiving device 21 is connected to the power supply device 3 or when the driving motor 24 is undergoing regenerative braking), the voltage supplied to the energy storage device 22 and the voltage supplied to the resistor 27 (described later) from the received voltage and regenerative voltage, and the voltage stored in the energy storage device 22.

[0026] More specifically, sensor 23 includes a voltage sensor 231 that detects the voltage in the power supply path between the pantograph 211 and the DC / DC converter 26. Sensor 23 also includes a voltage sensor 232 that more directly detects the voltage of the energy storage device 22, for example, by detecting the voltage between the positive terminal 221 and the negative terminal 222 of the energy storage device 22.

[0027] The driving motor 24 is driven by power supplied from the power receiving device 21 or the power storage device 22. More specifically, in this embodiment, the mining dump truck 2 has a rear-wheel drive system in which the rear wheels (left and right at the rear) are the drive wheels and the front wheels (left and right at the front) are the driven wheels. The driving motor 24 has a right driving motor (first driving motor) that drives the right rear wheel and a left driving motor (second driving motor) that drives the left rear wheel.

[0028] The drive motor 24 is powered by the pantograph 211 or the energy storage device 22 and is driven to perform rotational motion. In this embodiment, the rotation of the right drive motor causes the right rear wheel (right rear tire) to rotate, and the rotation of the left drive motor causes the left rear wheel (left rear tire) to rotate. In this way, the drive motor 24 is driven, causing the wheels of the mining dump truck 2 to rotate and the mining dump truck 2 to move.

[0029] Furthermore, the right and left drive motors of the drive motor 24 are rotated by the wheels when the mining dump truck 2 is braked, generating electricity and used for regenerative braking, which converts the kinetic energy of the mining dump truck 2 into electrical energy. Here, the electricity generated by using the drive motor 24 for regenerative braking is called regenerative power. In other words, the drive motor 24 is configured to rotate when power is supplied from the power receiving device 21 or the power storage device 22, and to generate regenerative power when it is braked while rotating.

[0030] The inverter 25 is installed between the traction motor 24 and the power receiving device 21 and the energy storage device 22. The inverter 25 has a right inverter (first inverter) 251 installed between the right traction motor (first traction motor) and the power receiving device 21 and the energy storage device 22, and a left inverter (second inverter) 252 installed between the left traction motor (second traction motor) and the power receiving device 21 and the energy storage device 22.

[0031] In this embodiment, the right inverter 251 is provided between the right travel motor and the power receiving device 21, and the left inverter 252 is provided between the left travel motor and the energy storage device 22. The inverters 25 are controlled, for example, by the control device 29, and convert the DC power supplied from the power supply device 3 or the energy storage device 22 into AC power and supply it to the travel motor 24, and also convert the regenerative power generated by the travel motor 24 into DC power and supply it to the energy storage device 22 or the resistor 27.

[0032] The DC / DC converter 26 is provided in the power supply path between the right and left inverters (first and second inverters) 251 and 252 of the inverter 25 and the energy storage device 22. In this embodiment, the DC / DC converter 26 is provided between the left inverter (second inverter) 252 and the energy storage device 22. The DC / DC converter 26 is controlled, for example, by the control device 29, and steps down the regenerative power supplied from the traction motor 24 via the inverter 25 to a predetermined voltage and supplies it to the energy storage device 22. The DC / DC converter 26 is also provided in the power supply path between the pantograph 211 of the power receiving device 21 and the energy storage device 22. The DC / DC converter 26 is controlled, for example, by the control device 29, and steps down the DC power supplied from the pantograph 211 of the power receiving device 21 to a predetermined voltage and supplies it to the energy storage device 22.

[0033] The resistor 27 is electrically connected to the right and left drive motors (first and second drive motors) of the drive motor 24 and converts the regenerative power generated by the regenerative braking of the drive motor 24 into heat. More specifically, the resistor 27 converts the regenerative power supplied from the drive motor 24 via the inverter 25 and chopper circuit 28 into heat and dissipates it into the atmosphere. The resistor 27 is mounted, for example, in the grid box of the mining dump truck 2.

[0034] The chopper circuit 28 is provided between the resistor 27 and the right and left drive motors (first and second drive motors) of the drive motor 24. More specifically, a right inverter 251 is provided between the chopper circuit 28 and the right drive motor, and the chopper circuit 28 is provided between the right inverter 251 and the resistor 27. In addition, a left inverter 252 is provided between the chopper circuit 28 and the left drive motor, and the chopper circuit 28 is provided between the left inverter 252 and the resistor 27. The chopper circuit 28 is controlled, for example, by a control device 29 to control the amount of regenerative power supplied to the resistor 27.

[0035] The control device 29 is comprised of one or more microcontrollers, for example, a central processing unit (CPU), memory, timers, and input / output units. The control device 29 is connected to the sensor 23 via signal lines, for example, and receives detection results from the sensor 23. In the example shown in Figure 3, the mining dump truck 2 has two control devices 29, but the mining dump truck 2 may have one or more control devices 29.

[0036] The control device 29, for example, executes a program stored in memory using the CPU to estimate the charge level of the energy storage device 22 based on the detection results of the sensor 23, and controls the inverter 25, DC / DC converter 26, chopper circuit 28, and switch box SB. More specifically, when the charge level of the energy storage device 22 estimated based on the detection results of the sensor 23 is below a predetermined lower limit, the control device 29 controls the DC / DC converter 26 and chopper circuit 28 to supply regenerative power from the driving motor 24 to the energy storage device 22.

[0037] Furthermore, when the charge level of the energy storage device 22 is higher than a predetermined upper limit, the control device 29 controls the DC / DC converter 26 and the chopper circuit 28 to supply regenerative power from the traction motor 24 to the resistor 27. The lower and upper limits of the charge level of the energy storage device 22 are set in advance by the control device 29 to have a predetermined range, for example, 60% and 80%, or 70% and 90%.

[0038] The switch box SB includes, for example, a first switch box SB1 provided in the power supply path between the pantograph 211 of the power receiving device 21 and the right inverter of the inverter 25, and a second switch box SB2 provided in the power supply path between the left inverter 252 of the inverter 25 and the DC / DC converter 26. The switch box SB is kept on, for example, when the mining dump truck 2 is started up and under normal conditions, and is turned off by the control device 29 when the mining dump truck 2 is idle and in predetermined cases, thereby interrupting the power supply path.

[0039] The auxiliary power device PD is connected to the pantograph 211 and inverter 25, for example, via a switch box SB. In this embodiment, the auxiliary power device PD is located between the second switch box SB2 and the DC / DC converter 26. The auxiliary power device PD supplies power to, for example, the air conditioning power supply, power device power supply, cooling system power supply, hydraulic system power supply, body control power supply, and lighting power supply of the mining dump truck 2.

[0040] Next, the configuration of the reference example that serves as the premise for this embodiment will be described. Figure 6 is a reference example of a low-voltage electrical circuit diagram for a first embodiment to which the power supply device for a construction machine of the present invention is applied.

[0041] The mining dump truck 2 has a power supply unit 100 for supplying low-voltage power to the low-voltage equipment 61. The power supply unit 100 in the reference example has a low-voltage battery 41 as a low-voltage power source. The low-voltage battery 41 is, for example, a 12V or 24V DC lead-acid battery or a lithium-ion secondary battery, and is mounted on the mining dump truck 2. In the example shown in Figure 6, the low-voltage battery 41 is a 24V battery made by connecting two 12V batteries in series and two in parallel, and is shown as a combination of multiple single cells 411, but a single cell is also acceptable.

[0042] The low-voltage battery 41 has a low-voltage device 61 connected to one electrode terminal, the positive terminal, and a disconnect switch 51 connected to the other electrode terminal, the negative terminal. The disconnect switch 51 is located between the negative terminal of the low-voltage battery 41 and the body ground. Ground lines 521 and 522 are provided between the disconnect switch 51 and the body ground as a power supply circuit 52.

[0043] When the disconnect switch 51 is in the ON position (conductive state), the negative terminal of the low-voltage battery 41 and the body ground are connected via ground lines 521 and 522. This results in a powered state where power is supplied from the low-voltage battery 41 to the low-voltage equipment 61.

[0044] On the other hand, when the disconnect switch 51 is in the OFF position (non-conductive state), the connection between the negative terminal of the low-voltage battery 41 and the body ground (ground lines 521, 522) is interrupted. As a result, power is not supplied from the low-voltage battery 41 to the low-voltage equipment 61.

[0045] Thus, the disconnect switch 51 is configured to switch between a powered state and a disconnected state between the low-voltage battery 41 and the low-voltage device 61. Furthermore, the disconnect switch 51 has a structure that allows switching between a powered state, where power can be supplied from the low-voltage battery 41 to the low-voltage device 61 when in the ON position, and a disconnected state, where the power supply from the low-voltage battery 41 to the low-voltage device 61 is cut off when in the OFF position.

[0046] The disconnect switch 51 has two switches 511 and 512 whose ON (powered) and OFF (disconnected) positions are linked to each other, and each is connected between the negative terminal of the low-voltage battery 41 and the body ground. The disconnect switch 51 is located on the front of the mining dump truck 2, which is easily accessible to the operator from the ground, as shown in Figure 1, for example.

[0047] The low-voltage equipment 61 is connected to the positive terminal of the low-voltage battery 41. The low-voltage equipment 61 includes ACC power equipment 723, which is powered by the low-voltage battery 41 when the key switch 71 is operated, key-on power equipment 724, a control device 29, and battery-powered equipment 72 such as a horn 721 and headlights 722, which are connected directly to the low-voltage battery 41 without going through the key switch 71.

[0048] The key switch 71 has a configuration that allows the operator of the mining dump truck 2 to switch to one of four key positions: key OFF, ACC, key ON, and START. The key switch 71 selects the power supply destination of the low-voltage battery for multiple power supply devices of the low-voltage equipment.

[0049] When the disconnect switch 51 is in the ON position (powered on) and the key position is in the key OFF position, power to the ACC power supply equipment 723 and the key ON power supply equipment 724, and the supply of controller power to the control device 29 are cut off. When the key position is in the ACC position, ACC power is supplied to the ACC power supply equipment 723, such as the interior lights and car navigation system.

[0050] When the key position is in the key ON position, the battery relay 76 is driven, supplying ON power to the key ON power supply devices 724 such as the air conditioner fan, camera, and wipers. Also, a key ON signal is supplied to each controller 291-294 and the monitor 73 of the control device 29. As a result, each controller 291-294 starts up and enters an ON state where they can communicate with each other via CAN, and the monitor 73 also enters an ON state where it is powered up, causing warning lights to illuminate, etc. When the key position is in the START position, a START signal is input to the DC / DC converter controller 291 of the control device 29 by a START signal circuit 77 that directly connects the START signal terminal of the key switch 71 to the DC / DC converter controller 291, and the DC / DC converter controller 291 performs a system start.

[0051] In the power supply unit 100 of the above example, if the disconnect switch 51 is in the ON position, battery-powered devices 72 such as the horn 721 and headlights 722 can be used regardless of the key position of the key switch 71, which may lead to the low-voltage battery 41 running out of power depending on usage. On the other hand, when the disconnect switch 51 is in the OFF position, the power supply from the low-voltage battery 41 to the low-voltage devices 61 is completely cut off, so there is no risk of the low-voltage battery 41 running out of power, but there is a problem that all of the low-voltage devices 61 become unusable.

[0052] Next, the configuration of the power supply unit 1 of this embodiment will be described with reference to Figure 4. In this embodiment, the same reference numerals are used for components that are the same as those in the power supply unit 100 of the reference example described above, and their detailed descriptions will be omitted.

[0053] The power supply unit 1 of this embodiment has a configuration that prevents power depletion when the disconnect switch 51 is in the OFF position (disconnected state) and enables the use of low-voltage equipment 61. The power supply unit 1 is characterized by having an external power supply circuit 81 that supplies power from an external power supply 34 to the low-voltage equipment 61 when the disconnect switch 51 is in the OFF position.

[0054] The external power supply circuit 81 has a positive electrode wire 812 connected to the positive electrode of the low-voltage battery 41, a negative electrode wire 811 connected to body ground when the disconnect switch 51 is in the OFF position, and connector terminals 813 provided at the ends of the positive electrode wire 812 and the negative electrode wire 811, which are detachably connected to the external power supply 34. The connector terminals 813, like the disconnect switch 51, are located on the front or side of the mining dump truck 2 for easy access by the operator from the ground.

[0055] The external power supply 34 is, for example, a 24V (volt) DC power supply and is installed, for example, in the pit work area or parking area of ​​the mining dump truck 2. The external power supply 34 has a positive electrode wire 342, a negative electrode wire 341, and connector terminals 343 provided at the ends of the positive electrode wire 342 and the negative electrode wire 341, which are detachably connected to the connector terminals 813 of the external power supply circuit 81.

[0056] With the disconnect switch 51 of the power supply unit 1 in the OFF position (disconnected state), power is supplied from the external power supply 34 to the low-voltage equipment 61 via the external power supply circuit 81 by connecting the connector terminal 813 of the external power supply circuit 81 to the connector terminal 343 of the external power supply 34 (this may be referred to as the external connection state).

[0057] Therefore, even when the disconnect switch 51 is in the OFF position, power can be supplied to the battery-powered equipment 72 from the external power supply 34. In addition, by selecting the ACC position or the ON position as the key position of the key switch 71, power can also be supplied to the ACC-powered equipment 723 and the key-ON-powered equipment 724 from the external power supply 34. Therefore, it is possible to prevent the low-voltage battery 41 from running out of power due to the use of low-voltage equipment 61 while the vehicle is idle.

[0058] Furthermore, in this embodiment, the power supply unit 1 has a disconnect switch 51 with three contacts 511, 512, and 513. Contact 513 is provided in the START signal circuit 78 that connects the START signal terminal of the key switch 71 to the DC / DC converter controller 291. The disconnect switch 51 is opened when it is in the OFF position (disconnected state), and the START signal circuit 78 is disconnected. Therefore, when the disconnect switch 51 is in the OFF position, even if the key position of the key switch 71 is operated to the START position, the START signal is not input to the DC / DC converter controller 291, the DC / DC converter 26 is not controlled by the DC / DC converter controller 291, and the system does not start. Thus, it is possible to prevent accidentally starting the power supply unit 1 while the external power supply 34 is connected.

[0059] [Second Embodiment] Next, a second embodiment to which the present invention is applied will be described with reference to the drawings. The power supply unit 1A of this embodiment has a configuration that prevents the power supply unit 1A from being accidentally started when the external power supply 34 is connected.

[0060] Specifically, a normally closed relay 74 is provided between the START position of the key switch 71 and the DC / DC converter controller 291, and a relay excitation circuit 814 is provided in the external power supply circuit 81. The relay excitation circuit 814 energizes the relay 74 via a loop circuit 345 located at the connector terminal 343 of the external power supply 34 when the connector terminal 813 of the external power supply circuit 81 is connected. When the relay 74 is energized, its contacts are opened, and the START signal circuit 79 connecting the key switch 71 and the DC / DC converter controller 291 is interrupted.

[0061] Therefore, by setting the disconnect switch 51 to the OFF position and connecting the connector terminal 813 of the external power supply circuit 81 to the connector terminal 343 of the external power supply 34, the relay 74 is energized, the START signal circuit 79 between the key switch 71 and the DC / DC converter controller 291 is interrupted, and the system cannot be started by the DC / DC converter controller 291 even if the key position of the key switch 71 is operated to the START position. This prevents the power supply unit 1A from being accidentally started while the external power supply 34 is connected.

[0062] Furthermore, the power supply unit 1A of this embodiment has an external power supply connection signal line 75 that branches off from the relay excitation circuit 814 and connects to the monitoring controller 294. By inputting the branch signal from the relay excitation circuit 814 of the relay 74 to the monitoring controller 294, the monitor 73 is configured to display that it is connected to the external power supply 34. This allows the operator to be alerted that the external power supply 34 is connected.

[0063] Although embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. For example, the embodiments described above are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add a configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0064] 1, 1A... Power supply unit, 2... Mining dump truck (construction machinery), 29... Control device, 291... DC / DC converter controller, 294... Monitor controller, 34... External power supply, 343... Connector terminals, 345... Loop circuit, 41... Low voltage battery, 51... Disconnect switch, 61... Low voltage equipment, 71... Key switch, 72... Battery-powered equipment, 73... Monitor, 74... Relay, 75... External power supply connection signal line, 77, 78, 79... START signal circuit, 81... External power supply circuit, 813... Connector terminals, 814... Relay excitation circuit, 100... Power supply unit (example)

Claims

1. A construction machine equipped with low-voltage equipment powered by a low-voltage battery, A disconnect switch for switching between the energized state and the disconnected state of the low-voltage battery and the low-voltage equipment, When the disconnect switch is switched to the disconnected state, an external power supply circuit is activated, which supplies power from the external power supply to the low-voltage device when an external power supply is connected. A construction machine characterized by having the following features.

2. A key switch for selecting the power supply destination of the low-voltage battery for multiple power supply devices of the low-voltage device, A control device for controlling the operation of the aforementioned construction machine, The system includes a signal circuit connecting the key switch and the control device, The construction machine according to claim 1, characterized in that the signal circuit is interrupted when the disconnect switch is switched to the interrupted state.

3. The construction machine according to claim 2, characterized in that the disconnect switch has a contact that blocks the signal circuit in the disconnected state.

4. The construction machine according to claim 2, characterized in that it has a relay that is energized by setting the disconnect switch to the disconnected state and connecting the external power supply to the external power supply circuit, thereby interrupting the signal circuit.

Images