Work machine

Abstract

The purpose of the present invention is to provide an electric work machine that makes it unnecessary for an operator to consciously switch between operation modes and that has excellent operability. An electric work machine 1, which uses electric power supplied from an external power supply 15 as motive power, comprises: an electric motor 18 that drives a hydraulic pump 19 which supplies hydraulic oil to a hydraulic actuator 9; an ignition switch 22 that allows or stops the supply of electric power to the electric motor 18; a gate lock lever 23 that allows or stops the supply of hydraulic oil to the hydraulic actuator 9; and a controller 21 that controls the operation of the work machine 1. The controller 21 switches between operation modes of the work machine 1 on the basis of the state of the ignition switch 22, the state of the gate lock lever 23, and the state of electric power supply from the external power supply 15.

Description

Work machinery

[0001] The present invention relates to an electric work machine.

[0002] Electrically-powered work machines that use a commercial external power source as a power source are known, and these types of work machines are often capable of operating in a number of different operating modes depending on the form of power supply from the external power source.

[0003] Patent Document 1 discloses a work vehicle that can operate by switching between a drive mode in which a battery charged with power supplied from an external power source or an electric motor is driven by power supplied from an external power source, and a charge mode in which a battery is charged with power supplied from an external power source.

[0004] JP 2008-308881 A

[0005] However, in the work vehicle disclosed in Patent Document 1, the operator must operate a dedicated input device such as a charging switch in order to switch operating modes, which is time-consuming.

[0006] In view of the above circumstances, an object of the present invention is to provide an electric work machine that is easy to operate and does not require the operator to consciously switch between operation modes.

[0007] In order to solve the above problems, the work machine of the present invention is an electric work machine powered by electricity supplied from an external power source, and comprises an electric motor that drives a hydraulic pump that supplies hydraulic oil to a hydraulic actuator, an ignition switch that allows or stops the supply of power to the electric motor, a locking device that allows or stops the supply of hydraulic oil to the hydraulic actuator, and a controller that controls the operation of the work machine, and is characterized in that the controller switches the operating mode of the work machine based on the state of the ignition switch, the state of the locking device, and the state of power supply from the external power source.

[0008] According to the present invention, it is possible to provide an electric work machine that is easy to operate and does not require the operator to consciously switch between operation modes.

[0009] Fig. 1 is a side view of a work machine according to an embodiment of the present invention; Fig. 2 is a block diagram showing the configuration of the drive system of the work machine shown in Fig. 1; Fig. 3 is a state transition diagram of the operation mode of the work machine shown in Fig. 2; Fig. 4 is a diagram explaining the two-way mode shown in Fig. 3; Fig. 5 is a time chart showing an example of the operation of the work machine that switches the operation mode shown in Fig. 3; Fig. 6 is a time chart showing another example of the operation of the work machine that switches the operation mode shown in Fig. 3; Fig. 7 is a diagram explaining a modified example of an external power detection device;

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0011] FIG. 1 is a side view of a work machine 1 according to this embodiment.

[0012] The work machine 1 is an electric work machine powered by electric power supplied from an external power source 15. Specifically, the work machine 1 is an electric work machine that is driven using at least one of the external power source 15 and an internal battery 7 that is charged with electric power supplied from the external power source 15 as its power supply source. The work machine 1 may be an electric construction machine such as an electric shovel, an electric wheel loader, or an electric crane. In this embodiment, an electric shovel will be described as an example of the work machine 1, as shown in FIG. 1 .

[0013] The work machine 1 shown in Fig. 1 is made up of a lower traveling body 2 and an upper rotating body 3. The lower traveling body 2 allows the work machine 1 to travel by crawlers driven by a traveling hydraulic motor 4. The upper rotating body 3 is driven by a swing hydraulic motor 5 and swings relative to the lower traveling body 2.

[0014] The upper rotating structure 3 is equipped with a front working implement 6, a battery 7, a cab 8, a power conversion device 14, etc. The front working implement 6 is equipped with a boom 11, an arm 12, a bucket 13, etc. The boom 11, the arm 12, and the bucket 13 are driven by a boom hydraulic cylinder 10a, an arm hydraulic cylinder 10b, and a bucket hydraulic cylinder 10c, respectively, which are provided on the upper rotating structure 3, to perform excavation work.

[0015] The power conversion device 14 is a device that converts power supplied from an external power source 15 via a power supply cable 16 into power that can be used by the work machine 1. The external power source 15 may be, for example, a power source connected to a commercial power distribution network owned by an electric power company, or may be a portable large-capacity power storage device. The external power source 15 in this embodiment may also be a power supply source that supplies AC power.

[0016] In this embodiment, actuators that are driven by hydraulic pressure, such as the boom hydraulic cylinder 10a, the arm hydraulic cylinder 10b, the bucket hydraulic cylinder 10c, the traveling hydraulic motor 4, and the swing hydraulic motor 5, are also collectively referred to as hydraulic actuators 9. The hydraulic actuators 9 are driven by a supply of hydraulic oil from a hydraulic pump 19 provided on the work machine 1.

[0017] FIG. 2 is a block diagram showing the configuration of the drive system of the work machine 1 shown in FIG.

[0018] The drive system of the work machine 1 includes a battery 7, a power conversion device 14, an electric motor 18, a hydraulic pump 19, a control valve 20, a hydraulic actuator 9, a controller 21, an ignition switch 22, a gate lock lever 23 (locking device), an operation lever 24, an operation feasibility determination device 25, and a notification device 27. The power conversion device 14 includes a converter 17a and an inverter 17b.

[0019] The battery 7 is a secondary battery such as a lithium-ion battery. The battery 7 is charged with power supplied from the external power source 15 and converted by a converter 17a. The battery 7 supplies the charged power to the electric motor 18 via an inverter 17b. A relay is built into the battery 7. The relay built into the battery 7 is turned on / off by a power supply enable / disable signal SG5 from the control unit 21a of the controller 21. This allows or stops the power supply from the battery 7 to the electric motor 18.

[0020] The converter 17a converts AC power supplied from the external power source 15 into DC power and supplies it to the battery 7 and the inverter 17b. The converter 17a has a built-in external power detection device 26 that detects power supply from the external power source 15. The external power detection device 26 is configured, for example, by a sensor (e.g., a voltage sensor) that detects power supplied from the external power source 15. When the external power detection device 26 detects power supply from the external power source 15, it transmits an external power detection signal SG3 to the controller 21. The converter 17a has a built-in relay. The relay built in the converter 17a is turned on / off by a power supply enable / disable signal SG4 from the control unit 21a of the controller 21. This allows or stops power supply from the converter 17a to the battery 7 and the inverter 17b.

[0021] The inverter 17b converts DC power supplied from the converter 17a or the battery 7 into AC power and supplies it to the electric motor 18. At this time, the inverter 17b controls the AC power in accordance with a rotation speed command signal from the controller 21. As a result, the inverter 17b drives the electric motor 18 in accordance with the rotation speed command signal. A switching element such as an IGBT is built into the inverter 17b. The switching element built into the inverter 17b is turned ON / OFF by a power supply enable / disable signal SG6 from the control unit 21a of the controller 21. As a result, the power supply from the inverter 17b to the electric motor 18 is enabled or disabled.

[0022] The electric motor 18 is an AC motor that is operated by AC power supplied from the inverter 17 b. The rotary shaft of the electric motor 18 is connected to the rotary shaft of the hydraulic pump 19. The electric motor 18 drives the hydraulic pump 19.

[0023] The hydraulic pump 19 is driven by the electric motor 18 and supplies hydraulic oil to the hydraulic actuator 9 via a control valve 20. The hydraulic pump 19 supplies hydraulic oil at a discharge rate corresponding to an operation lever signal SG7 transmitted from an operation lever 24. The control valve 20 distributes the hydraulic oil supplied from the hydraulic pump 19 to the boom hydraulic cylinder 10a, the arm hydraulic cylinder 10b, the bucket hydraulic cylinder 10c, the traveling hydraulic motor 4, the swing hydraulic motor 5, etc.

[0024] The ignition switch 22 is a switch that is operated by an operator to start or stop (shut down) the work machine 1. The ignition switch 22 starts or stops the work machine 1, for example, by the operator turning the key cylinder to on or off. When the work machine 1 starts or stops, the supply of power to the electric motor 18 is allowed or stopped. In other words, the ignition switch 22 allows or stops the supply of power to the electric motor 18. When the ignition switch 22 is operated to a state that allows the supply of power to the electric motor 18, it sends an ignition signal SG1 to the controller 21.

[0025] The control lever 24 is a device that is operated by the operator and into which various operations are input to move the undercarriage 2, the upper rotating body 3, and the front working implement 6 at any desired speed. When the control lever 24 is operated by the operator, it transmits a control lever signal SG7 to the hydraulic pump 19 via an operation possibility determination device 25.

[0026] The gate lock lever 23 is an input device that is operated by an operator to switch the operation lever signal SG7 between enabled and disabled. When an operation to enable the operation lever signal SG7 is input, the gate lock lever 23 allows the supply of hydraulic oil to the hydraulic actuator 9, and when an operation to disable the operation lever signal SG7 is input, the gate lock lever 23 stops the supply of hydraulic oil to the hydraulic actuator 9. In other words, the gate lock lever 23 is a locking device that allows or stops (blocks) the supply of hydraulic oil to the hydraulic actuator 9. When the gate lock lever 23 is operated to a state that allows the supply of hydraulic oil, it transmits a gate lock signal SG2 to the controller 21 and the operation feasibility determination device 25.

[0027] The gate lock lever 23 may allow or stop the supply of hydraulic oil to the hydraulic actuator 9 by connecting or disconnecting the supply path of hydraulic oil from the hydraulic pump 19 to the control valve 20 depending on its operation. Alternatively, the gate lock lever 23 may allow or stop the supply of hydraulic oil to the hydraulic actuator 9 by connecting or disconnecting the transmission path of the operation lever signal SG7 from the operation lever 24 to the hydraulic pump 19 depending on its operation.

[0028] Based on the gate lock signal SG2, the operation feasibility determination device 25 allows or stops transmission of the operation lever signal SG7 from the operation lever 24 to the hydraulic pump 19. When the operation feasibility determination device 25 receives the gate lock signal SG2, it allows transmission of the operation lever signal SG7 from the operation lever 24 to the hydraulic pump 19. When the operation feasibility determination device 25 does not receive the gate lock signal SG2, it stops transmission of the operation lever signal SG7 from the operation lever 24 to the hydraulic pump 19.

[0029] The controller 21 has a control unit 21a that controls the operation of the work machine 1 using a plurality of different operation modes. Furthermore, the controller 21 has an operation switching unit 21b that switches the operation mode based on the state of the ignition switch 22, the state of the gate lock lever 23, and the state of power supply from the external power source 15. Furthermore, the controller 21 has an alarm unit 21c that causes the alarm device 27 to issue an alarm.

[0030] Specifically, the operation switching unit 21b of the controller 21 switches the operation mode based on the reception status of the ignition signal SG1, gate lock signal SG2, and external power detection signal SG3. The control unit 21a of the controller 21 can control the operation of the work machine 1 to an operation corresponding to the operation mode by transmitting power supply availability signals SG4 to SG6 to the converter 17a, battery 7, and inverter 17b, respectively. Details of the multiple operation modes of the work machine 1 will be described later using FIG. 3. Furthermore, when switching the operation mode, the notification unit 21c of the controller 21 transmits a notification control signal SG8 to the notification device 27, causing the notification device 27 to issue an alarm.

[0031] The alarm device 27 issues an alarm to the operator in the cab 8 and workers in the vicinity of the work machine 1, based on an alarm control signal SG8 from the alarm unit 21c of the controller 21. The alarm device 27 issues a sound to the operator and workers in the vicinity as an alarm, and also displays text, images, etc. on a display inside the cab 8.

[0032] Fig. 3 is a state transition diagram of the operation modes of the work machine 1 shown in Fig. 2. Fig. 4 is a diagram for explaining the two-way mode shown in Fig. 3.

[0033] The multiple operating modes include a stop mode, a charge mode, a battery-powered mode, and a two-way mode. The stop mode is an operating mode in which all power supply is stopped. In the stop mode, power supply from the external power source 15 and the battery 7 to the electric motor 18 is stopped, and power supply from the external power source 15 to the battery 7 is also stopped. The charge mode is an operating mode in which power is supplied from the external power source 15 to the battery 7 while the supply of hydraulic oil to the hydraulic actuator 9 is stopped. The battery-powered mode is an operating mode in which power is supplied from the battery 7 to the electric motor 18 while the power supply from the external power source 15 to the electric motor 18 is stopped. The two-way mode is an operating mode in which power is supplied from the external power source 15 to the electric motor 18, or power is supplied from the external power source 15 and the battery 7 to the electric motor 18.

[0034] 4, in the two-way mode, the form of power supply to the electric motor 18 differs depending on the magnitude relationship between the electric power W1 to be supplied to the electric motor 18 and the electric power W2 supplied from the external power supply 15. The controller 21 supplies electric power from the external power supply 15 to the electric motor 18 with priority over electric power from the battery 7, while charging the battery 7.

[0035] Specifically, when the electric power W1 is greater than the electric power W2 in the two-way mode, the controller 21 not only supplies the electric power W2 supplied from the external power source 15 to the electric motor 18, but also discharges the battery 7 to make up for the shortfall in electric power (W1 - W2) and supplies electric power to the electric motor 18. When the electric power W1 is approximately equal to the electric power W2 in the two-way mode, the controller 21 supplies the electric power W2 supplied from the external power source 15 to the electric motor 18. The battery 7 neither discharges nor charges. When the electric power W1 is less than the electric power W2 in the two-way mode, the controller 21 not only supplies the electric power W2 supplied from the external power source 15 to the electric motor 18, but also supplies the surplus electric power (W2 - W1) to the battery 7 to charge it. This allows the work machine 1 to continue work even if the electric power W2 supplied from the external power source 15 is insufficient, and also ensures the power supply capacity of the internal power supply source, the battery 7. Therefore, the work machine 1 can improve its ability to continue working, regardless of the power supply capacity of the external power source 15.

[0036] The operation switching unit 21b of the controller 21 switches the operation mode to the charging mode, the battery-powered mode, the two-way mode, or the stop mode based on the reception status of the ignition signal SG1, the gate lock signal SG2, and the external power detection signal SG3. Note that in Fig. 3, when the controller 21 receives the signals SG1 to SG3, it is represented as ON, and when it does not receive the signals SG1 to SG3, it is represented as OFF.

[0037] In stop mode, the ignition signal SG1 is OFF, the gate lock signal SG2 is OFF, and the external power detection signal SG3 is OFF. In stop mode, when the ignition signal SG1 is OFF and the external power detection signal SG3 turns ON, the operation switching unit 21b of the controller 21 switches to charge mode. In stop mode, when the ignition signal SG1 turns ON, the operation switching unit 21b of the controller 21 starts the work machine 1, and when the gate lock signal SG2 turns ON, the operation switching unit 21b of the controller 21 switches to battery drive mode.

[0038] In the charging mode, the ignition signal SG1 is ON or OFF, the gate lock signal SG2 is OFF, and the external power detection signal SG3 is ON. In the charging mode, when the ignition signal SG1 and the gate lock signal SG2 are both ON while the external power detection signal SG3 is ON, the operation switching unit 21b of the controller 21 switches to the two-way mode. That is, in the charging mode, when the external power detection device 26 detects power supply from the external power source 15, the ignition switch 22 is set to a state allowing power supply to the electric motor 18, and the gate lock lever 23 is set to a state allowing hydraulic oil supply, the operation switching unit 21b of the controller 21 switches to the two-way mode. In the charging mode, when the ignition signal SG1 is OFF and the external power detection signal SG3 is set to OFF, the operation switching unit 21b of the controller 21 switches to the stop mode regardless of the gate lock signal SG2.

[0039] In the two-way mode, the ignition signal SG1 is ON, the gate lock signal SG2 is ON, and the external power detection signal SG3 is ON. In the two-way mode, if the gate lock signal SG2 turns OFF while the external power detection signal SG3 is ON, the operation switching unit 21b of the controller 21 switches to the charging mode regardless of the ignition signal SG1. That is, in the two-way mode, if the external power detection device 26 detects the supply of power from the external power source 15 and the gate lock lever 23 is set to a state that stops the supply of hydraulic oil, the operation switching unit 21b of the controller 21 switches to the charging mode. In the two-way mode, if the ignition signal SG1 is ON, the gate lock signal SG2 is ON, and the external power detection signal SG3 turns OFF, the operation switching unit 21b of the controller 21 switches to the battery-powered mode. That is, in the two-way mode, when the ignition switch 22 is in a state permitting the supply of power to the electric motor 18 and the gate lock lever 23 is in a state permitting the supply of hydraulic oil and the external power detection device 26 does not detect the supply of power from the external power source 15, the operation switching unit 21b of the controller 21 switches to the battery-powered mode. In the two-way mode, when the ignition signal SG1 is OFF and the external power detection signal SG3 is OFF, the operation switching unit 21b of the controller 21 switches to the stop mode regardless of the gate lock signal SG2.

[0040] In the battery-powered mode, the ignition signal SG1 is ON, the gate lock signal SG2 is ON, and the external power detection signal SG3 is OFF. In the battery-powered mode, if the ignition signal SG1 turns OFF while the external power detection signal SG3 is OFF, the operation switching unit 21b of the controller 21 switches to the stop mode regardless of the gate lock signal SG2.

[0041] The notification unit 21c of the controller 21 causes the notification device 27 to issue an alarm when switching from the stop mode to the charge mode and when switching from the charge mode to the two-way mode. Furthermore, the notification unit 21c of the controller 21 causes the notification device 27 to issue an alarm in a different manner from the alarms issued when switching from the two-way mode to the battery-powered mode, when switching from the stop mode to the charge mode, and when switching from the charge mode to the two-way mode.

[0042] Figure 5 is a time chart showing an example of the operation of the work machine when switching between the operation modes shown in Figure 3. Figure 5 shows an example of the operation of the work machine 1 from stop mode, through charge mode, two-way mode and battery-powered mode in that order, until switching back to stop mode.

[0043] 5 and 6, the converter output current indicates the current supplied from the converter 17a to each device (at least one of the battery 7 and the inverter 17b), and the inverter output current indicates the current supplied from the inverter 17b to the electric motor 18.

[0044] At time t1, when the operator connects the converter 17a of the work machine 1 to the external power supply 15 with the power supply cable 16 and the external power detection signal SG3 turns ON, the controller 21 switches the operation mode from stop mode to charge mode. When the mode is switched to charge mode, the converter output current begins to flow, and power is supplied to the battery 7, charging the battery 7.

[0045] At time t2, the operator operates the ignition switch 22 to turn on the ignition signal SG1, and then operates the gate lock lever 23 to turn on the gate lock signal SG2, causing the controller 21 to switch the operating mode from the charging mode to the two-way mode. When the mode is switched to the two-way mode, the inverter output current begins to flow, and power is supplied to the electric motor 18.

[0046] At time t3, when the operator operates the gate lock lever 23 to turn off the gate lock signal SG2, the controller 21 switches the operation mode from the two-way mode to the charge mode. When the mode is switched to the charge mode, the inverter output current stops flowing, and the power supply to the electric motor 18 stops.

[0047] At time t4, when the operator operates the gate lock lever 23 and the gate lock signal SG2 is turned ON, the controller 21 switches the operation mode from the charging mode to the two-way mode. When the mode is switched to the two-way mode, the inverter output current begins to flow, and power is supplied to the electric motor 18.

[0048] At time t5, when the power supply cable 16 is disconnected from the external power supply 15 or the converter 17a and the external power detection signal SG3 is turned OFF, the controller 21 switches from the two-way mode to the battery-powered mode. When the mode is switched to the battery-powered mode, the converter output current stops flowing, and the battery 7 discharges to supply power to the inverter 17b.

[0049] At time t6, the operator operates the gate lock lever 23 to turn off the gate lock signal SG2, and then operates the ignition switch 22 to turn off the ignition signal SG1, causing the controller 21 to switch the operating mode from the battery-powered mode to the stop mode. When the mode is switched to the stop mode, the converter output current and the inverter output current stop flowing, and charging and discharging of the battery 7 stops.

[0050] Fig. 6 is a time chart showing another example of the operation of the work machine when switching between the operation modes shown in Fig. 3. Fig. 6 shows an example of the operation of the work machine 1 from the stop mode via the battery-powered mode until switching back to the stop mode.

[0051] At time t11, the operator operates the ignition switch 22 to turn on the ignition signal SG1, and then operates the gate lock lever 23 to turn on the gate lock signal SG2, causing the controller 21 to switch the operation mode from the stop mode to the battery-powered mode. When the mode is switched to the battery-powered mode, the battery 7 discharges and supplies power to the inverter 17b. The inverter output current begins to flow, and power is supplied to the electric motor 18.

[0052] At time t12, the operator operates the gate lock lever 23 to turn off the gate lock signal SG2, and then operates the ignition switch 22 to turn off the ignition signal SG1, causing the controller 21 to switch the operating mode from the battery-powered mode to the stop mode. When the mode is switched to the stop mode, the converter output current and the inverter output current stop flowing, and charging and discharging of the battery 7 stops.

[0053] As described above, the work machine 1 of this embodiment is an electrically powered work machine powered by electricity supplied from the external power source 15. The work machine 1 is equipped with an electric motor 18 that drives a hydraulic pump 19 that supplies hydraulic oil to the hydraulic actuator 9. The work machine 1 is equipped with an ignition switch 22 that allows or stops the supply of power to the electric motor 18, and a gate lock lever 23 that is a locking device that allows or stops the supply of hydraulic oil to the hydraulic actuator 9. The work machine 1 is equipped with a controller 21 that controls the operation of the work machine 1. The controller 21 switches the operation mode of the work machine 1 based on the state of the ignition switch 22, the state of the gate lock lever 23, and the state of power supply from the external power source 15.

[0054] As a result, the work machine 1 of this embodiment can automatically switch operating modes simply by the operator operating the ignition switch 22, gate lock lever 23, etc., which are standard equipment on the work machine 1. In other words, the work machine 1 of this embodiment is provided with a dedicated input device for switching operating modes, and can automatically switch operating modes without the operator having to perform a dedicated operation to input data into the input device. Therefore, the work machine 1 of this embodiment can save the operator the trouble of operating a dedicated input device to switch operating modes. Therefore, according to this embodiment, it is possible to provide an electrically powered work machine with excellent operability, without the operator having to consciously switch operating modes.

[0055] Furthermore, the work machine 1 of this embodiment is further equipped with an internally provided battery 7, and an external power detection device 26 that detects the supply of power from the external power source 15. The operation modes include a charge mode in which power is supplied from the external power source 15 to the battery 7 while the supply of hydraulic oil to the hydraulic actuator 9 is stopped, and a battery drive mode in which power is supplied from the battery 7 to the electric motor 18 while the power supply from the external power source 15 to the electric motor 18 is stopped. The operation modes include a two-way mode in which power is supplied from the external power source 15 to the electric motor 18, or a two-way mode in which power is supplied from both the external power source 15 and the battery 7 to the electric motor 18. The controller 21 switches the operation mode between the charge mode, battery drive mode, and two-way mode based on the states of the ignition switch 22, the gate lock lever 23, and the external power detection device 26.

[0056] As a result, the working machine 1 of this embodiment can switch its operating mode between charge mode, battery-powered mode, and two-way mode simply by the operator operating the ignition switch 22, gate lock lever 23, etc., which are standard equipment on the working machine 1. Therefore, the working machine 1 of this embodiment can switch to an operating mode that is suited to the form of power supply from the power supply sources, that is, the battery 7 and external power supply 15, without the need for a dedicated input device or dedicated operation. Therefore, according to this embodiment, there is no need for the operator to consciously switch between operating modes appropriately, and it is possible to provide an electrically powered working machine that is even easier to operate.

[0057] Furthermore, in the working machine 1 of this embodiment, the controller 21 switches to the two-way mode in the charging mode when the external power detection device 26 detects the supply of power from the external power source 15, the ignition switch 22 is set to a state that allows the supply of power to the electric motor 18, and the gate lock lever 23 is set to a state that allows the supply of hydraulic oil. In the two-way mode, the controller 21 switches to the charging mode when the external power detection device 26 detects the supply of power from the external power source 15, and the gate lock lever 23 is set to a state that stops the supply of hydraulic oil.

[0058] That is, the work machine 1 of this embodiment can be switched from charge mode to two-way mode simply by the operator performing standard operations on the ignition switch 22 and gate lock lever 23 that are standard equipment on the work machine 1. Furthermore, the work machine 1 of this embodiment can be switched from two-way mode to charge mode even if the ignition switch 22 is not operated to a state that stops the supply of power to the electric motor 18. Therefore, the work machine 1 of this embodiment can be switched from two-way mode to charge mode without putting the work machine 1 into an operational stop state, and therefore can quickly switch from two-way mode to charge mode. Therefore, according to this embodiment, there is no need for the operator to consciously switch between operating modes quickly, and an electric work machine with even better operability can be provided.

[0059] Furthermore, in the working machine 1 of this embodiment, in the two-way mode, when the ignition switch 22 is in a state allowing the supply of power to the electric motor 18 and the gate lock lever 23 is in a state allowing the supply of hydraulic oil, and the external power detection device 26 does not detect the supply of power from the external power source 15, the controller 21 switches to the battery-powered mode.

[0060] As a result, even if the power supply from the external power source 15 is suddenly stopped due to the power supply cable 16 being unexpectedly disconnected or a power outage or the like, the work machine 1 of this embodiment does not immediately switch to stop mode, but switches to battery-powered mode and can continue working with the work machine 1. Therefore, the work machine 1 of this embodiment can prevent the work machine 1 from suddenly stopping, and can prevent accidents such as the work machine 1 tipping over. Therefore, according to this embodiment, there is no need for the operator to consciously switch between operating modes safely, and it is possible to provide an electrically powered work machine that is even easier to operate.

[0061] Furthermore, the work machine 1 of this embodiment is further equipped with an alarm device 27 that issues an alarm. The multiple operation modes further include a stop mode in which all power supply is stopped. The controller 21 causes the alarm device 27 to issue an alarm when switching from the stop mode to the charge mode, and when switching from the charge mode to the two-way mode.

[0062] As a result, the work machine 1 of this embodiment can alert and alert the operator and nearby workers that a transition is being made from a state in which power supply to the electric motor 18 is stopped to a state in which power supply to the electric motor 18 is permitted. Therefore, according to this embodiment, the operator does not need to consciously switch between operation modes safely, and an electric work machine with even greater operability can be provided.

[0063] Furthermore, in the work machine 1 of this embodiment, when switching from two-way mode to battery-powered mode, the controller 21 causes the alarm device 27 to issue an alarm in a different alarm mode than when switching from stop mode to charge mode and when switching from charge mode to two-way mode.

[0064] As a result, the work machine 1 of this embodiment can alert the operator and nearby workers to the fact that the power supply from the external power source 15 has suddenly stopped, and call their attention to this. Therefore, according to this embodiment, it is not necessary for the operator to consciously switch between operation modes safely, and it is possible to provide an electrically powered work machine that is even easier to operate.

[0065] FIG. 7 is a diagram illustrating a modified example of the external power detection device 26. In FIG.

[0066] 2 is configured by a sensor built into the converter 17a and detects the power supplied from the external power supply 15. However, the external power detection device 26 is not limited to this.

[0067] For example, the external power detection device 26 may detect the connection state of the power feed cable 16 that connects the external power source 15 and the work machine 1. Then, when the power feed cable 16 connects the external power source 15 and the work machine 1, the external power detection device 26 may transmit an external power detection signal SG3 to the controller 21.

[0068] For example, as shown in Fig. 7 , a circuit breaker 29 may be provided on a power supply path 28 inside the work machine 1 between the external power source 15 and the battery 7. The circuit breaker 29 is provided between the external power source 15 and the converter 17a, and cuts off the power supply from the external power source 15 in the event of a failure or the like of the converter 17a. The circuit breaker 29 is activated by a power supply availability signal SG4 from the control unit 21a of the controller 21. The external power detection device 26 may detect the activation state of the circuit breaker 29. Then, when the circuit breaker 29 is in a state where the power supply from the external power source 15 is not cut off, the external power detection device 26 may transmit an external power detection signal SG3 to the controller 21.

[0069] The external power supply 15 may be a power supply source that supplies DC power. In this case, the converter 17a is configured by a DC-DC converter and converts the DC power supplied from the external power supply 15 into DC power that can be used by the battery 7 and the inverter 17b.

[0070] In this way, the external power detection device 26 of this embodiment can detect the power supply from the external power source 15 based on at least one of the detection results of the sensor that detects the power supplied from the external power source 15, the connection state of the power supply cable 16 that connects the external power source 15 and the work machine 1, and the operation state of the circuit breaker 29 provided on the power supply path 28 between the external power source 15 and the battery 7.

[0071] As a result, the external power detection device 26 of this embodiment can detect power supplies from various external power sources 15. Therefore, the work machine 1 of this embodiment can switch operating modes without having to provide dedicated input devices and dedicated operations for various models of work machine 1. Therefore, according to this embodiment, it is possible to provide an electrically powered work machine that is easy to operate and has excellent versatility, without the operator having to consciously switch operating modes.

[0072] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention as defined in the claims. In the present invention, the configuration of one embodiment can be added to the configuration of another embodiment, the configuration of one embodiment can be replaced with the configuration of another embodiment, or part of the configuration of one embodiment can be deleted.

[0073] REFERENCE SIGNS LIST 1...work machine, 7...battery, 9...hydraulic actuator, 15...external power source, 16...power supply cable, 18...electric motor, 19...hydraulic pump, 21...controller, 22...ignition switch, 23...gate lock lever (locking device), 26...external power detection device, 27...alarm device, 28...power supply path, 29...circuit breaker

Claims

1. An electric working machine powered by electric power supplied from an external power source, a battery provided inside, an external power detection device for detecting electric power supplied from the external power source, an electric motor for driving a hydraulic pump that supplies hydraulic oil to a hydraulic actuator, an ignition switch for allowing or stopping the supply of electric power to the electric motor, a lock device for allowing or stopping the supply of the hydraulic oil to the hydraulic actuator, and a controller for controlling the operation of the working machine, The controller switches the operation mode of the working machine among a charging mode in which electric power is supplied from the external power source to the battery with the supply of the hydraulic oil to the hydraulic actuator stopped, a battery drive mode in which electric power is supplied from the battery to the electric motor with the supply of electric power from the external power source to the electric motor stopped, and a two-way mode in which electric power is supplied from the external power source to the electric motor or electric power is supplied from the external power source and the battery to the electric motor, based on the state of the ignition switch, the state of the lock device, and the supply state of electric power from the external power source. A working machine characterized by the above.

2. Among the switching between the battery drive mode and the two-way mode in the switching of the operation mode between the charging mode, the battery drive mode, and the two-way mode, the controller allows the switching from the two-way mode to the battery drive mode, while making the switching from the battery drive mode to the two-way mode impossible. The working machine according to claim 1, characterized by the above.

3. The controller, In the charging mode, when the external power detection device detects power supply from the external power source, the ignition switch is in a state of allowing power supply to the electric motor, and the lock device is in a state of allowing supply of the hydraulic oil, the two-way mode is switched to. In the two-way mode, when the external power detection device detects power supply from the external power source and the lock device is in a state of stopping the supply of the hydraulic oil, the charging mode is switched to. The work machine according to claim 2, characterized in that.

4. In the two-way mode, when the ignition switch is in a state of allowing power supply to the electric motor and the lock device is in a state of allowing supply of the hydraulic oil, and the external power detection device does not detect power supply from the external power source, the controller switches to the battery drive mode. The work machine according to claim 2, characterized in that.

5. The work machine further includes a notification device that notifies an alarm. The operation mode further includes a stop mode in which all power supplies are stopped. When the controller switches from the stop mode to the charging mode and when switching from the charging mode to the two-way mode, the controller causes the notification device to notify the alarm. The work machine according to claim 2, characterized in that.

6. When the controller switches from the two-way mode to the battery drive mode, the controller causes the notification device to notify the alarm in a notification mode different from when switching from the stop mode to the charging mode and when switching from the charging mode to the two-way mode. The work machine according to claim 5, characterized in that.

7. The external power detection device detects power supply from the external power source based on at least one of a detection result of a sensor that detects power supplied from the external power source, a connection state of a power supply cable that connects the external power source and the work machine, and an operating state of a circuit breaker provided on a power supply path between the external power source and the battery. The work machine according to claim 1, characterized in that.