Patent ID: 12188201

DETAILED DESCRIPTION

An electrically operated excavator is typically relatively small in size and tends to have a relatively small space at the rear portion of the upper turning body. Further, an excavator of a relatively small size is required to have workability in a narrow worksite. Therefore, in some cases, the turning radius of the rear portion of the upper turning body is configured to be relatively small, and the space at the rear portion of the upper turning body may be small. For this reason, when a power storage device (a battery) is mounted on the rear portion of the upper turning body as in the conventional technology, for example, there is a possibility that a power storage device with the necessary capacity cannot be mounted on the upper turning body in accordance with the user's usage mode.

Therefore, it is desirable to provide a technology for efficiently arranging a power storage device in an upper turning body of an electrically operated excavator.

Hereinafter, an embodiment for carrying out the invention will be described with reference to the drawings.

[Overview of Excavator]

First, an overview of an excavator100as an example of a work machine will be described with reference toFIG.1.

FIG.1is a side view illustrating an example of the excavator100according to the present embodiment.

The excavator100includes a lower traveling body1, an upper turning body3that is mounted to the lower traveling body1in a turnable manner via a turning mechanism2, an attachment AT, and a cabin10in which an operator is to be seated.

As described below, the cabin10may be omitted when the excavator100is remotely operated or the excavator100operates by a fully automatic operation.

The lower traveling body1includes, for example, a pair of left and right crawlers10(an example of a driven part). In the lower traveling body1, each crawler1C travels by being hydraulically driven by traveling hydraulic motors1A and1B (seeFIGS.2and3).

The upper turning body3(an example of a driven part) is hydraulically driven by a turning hydraulic motor2A via the turning mechanism2(seeFIGS.2and3).

The attachment AT includes a boom4, an arm5, and a bucket6.

The boom4(an example of a driven part) is pivotally mounted to the front center of the upper turning body3, the arm5(an example of a driven part) is mounted to the leading end of the boom4so as to turn upward and downward, and the bucket6(an example of a driven part) is mounted to the leading end of the arm5so as to turn upward and downward. The boom4, the arm5, and the bucket6are hydraulically driven by a boom cylinder7, an arm cylinder8, and a bucket cylinder9as hydraulic actuators.

The bucket6is an example of an end attachment and is used for drilling work, rolling work, and the like.

Other end attachments may be attached to the leading end of the arm5, instead of the bucket6, depending on the work content and the like. Other end attachments may be, for example, buckets of a type different from the bucket6, such as a slope bucket, a dredger bucket, or the like. Other end attachments may also be, for example, end attachments of a type different from buckets, such as a breaker, an agitator, a grappler, and the like. Also, in the coupling part between the end attachment including the bucket6and the arm5may be provided with an auxiliary attachment such as, for example, a quick coupling, a tilt rotator, or the like.

In this example, as will be described later, in the excavator100, all driven parts are hydraulically driven by the hydraulic oil supplied from a main pump14(seeFIG.2) which is powered by a pump motor12. That is, in this example, the excavator100has a configuration in which a motor (engine) of what is known as a hydraulic excavator is replaced with the pump motor12.

Some of or all of the driven parts of the excavator100may be electrically driven. For example, the upper turning body3may be electrically driven by a turning motor via the turning mechanism2to turn relative to the lower traveling body1.

The cabin10is mounted, for example, on the front left side of the upper turning body3, and the inside of the cabin10is provided with an operation seat on which an operator is seated and an operation device26to be described later.

As described below, the cabin10may be omitted when the excavator100is remotely operated or the excavator100operates by a fully automatic operation.

The excavator100operates the driven parts, such as the lower traveling body1(the left and right crawlers1C), the upper turning body3, the boom4, the arm5, and the bucket6, according to the operation of an operator seated in the cabin10.

Further, the excavator100may be remotely operable (remote control) from outside the excavator100, instead of or in addition to being operable by an operator seated in the cabin10. When the excavator100is remotely operated, the interior of the cabin10may be unmanned. The following discussion assumes that the operation by the operator includes an operation with respect to the operation device26by an operator in the cabin10and/or remote operation by an external operator.

The remote operation includes a mode in which the excavator100is operated, for example, by an operation input relating to an actuator of the excavator100performed at a predetermined external device. The external device includes, for example, a management apparatus for managing the excavator100, a terminal apparatus (user terminal), and the like, used by a user of the excavator100. Hereinafter, the same may apply to remote monitoring as described below. In this case, the excavator100may be provided with a communication device capable of communicating with the external device, and for example, the excavator100may transmit an image representing the state around the excavator100based on image information (captured image), output by an imaging device included in the surrounding information acquiring device40, which will be described later (hereinafter referred to as the “surrounding image”), to the external device. The external device may display a surrounding image of the excavator100that is received by a display device (hereinafter, “a display device for remote operation”) arranged in the external device. Various information images (information screens) displayed on the output device50(display device) inside the cabin10of the excavator100may also be displayed on the display device for remote operation of the external device. Accordingly, the operator of the external device can remotely operate the excavator100while confirming the display contents of the surrounding image of the excavator100displayed on the remote operation display device, the information screen, or the like. The excavator100may operate an actuator in response to a remote operation signal representing the content of the remote operation, received from an external device by a communication device, to drive a driven part such as the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like.

The remote operation may also include a mode in which the excavator100is operated, for example, by voice sound input, gesture input, or the like, from outside to the excavator100, from a person (e.g., a worker) around the excavator100. Specifically, the excavator100recognizes a voice that is spoken by a nearby worker or the like or a gesture that is carried out by a worker or the like through a voice sound input device (e.g., a microphone) or a gesture input device (e.g., an imaging device) mounted on the excavator100(own machine). The excavator100may operate an actuator in accordance with the content of the recognized voice, gesture, or the like to drive a driven part, such as the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like.

The excavator100may also automatically operate the actuator regardless of the operator's operation. Thus, the excavator100implements a function (what is referred to as “automatic operation function” or “machine control (MC) function”) to automatically operate at least some of the driven parts including the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like.

The automatic operation function may include a function to automatically operate a driven part (actuator) other than the driven parts (actuators) that are the targets of operation, in accordance with an operation or a remote operation by the operator with respect to the operation device26(what is referred to as a “semi-automatic operation function” or “operation-assisted MC function”). The automatic operation function may include a function to automatically operate at least some of a plurality of driven parts (actuators), on the assumption that there is no operation or remote operation performed by the operator on the operation device26(what is referred to as a “fully automatic operation function” or a “fully automatic MC function”). In the excavator100, the interior of the cabin10may be unmanned if a fully automatic operation function is enabled. Further, the semi-automatic operation function, the fully automatic operation function, or the like may include a mode in which the operation content of the driven part (actuator) subject to automatic operation is automatically determined in accordance with a predetermined rule. Further, the semi-automatic operation function, the fully automatic operation function, or the like may include a mode in which the excavator100autonomously makes various determinations, and the operation content of the driven part (actuator) subject to automatic operation is autonomously determined, based on the determination result (what is referred to as “autonomous operation function”).

Further, when the excavator100operates by an automatic operation function (particularly a fully automatic operation function), the work status of work by the excavator100may be remotely monitored from outside the excavator100.

When remote monitoring is performed, the excavator100may be provided with a communication device capable of communicating with the external device and transmit, for example, an image (surrounding image) representing the surrounding state of the excavator100based on image information output by the imaging device included in the surrounding information acquiring device40, which will be described later, to the external device. The external device may display image information (captured image) received by a display device (hereinafter, a “display device for remote monitoring”) arranged in the external device. Various information images (information screens) displayed on the output device50(display device) inside the cabin10of the excavator100may also be displayed on the display device for remote monitoring of the external device in the same manner. Thus, the monitoring person at the external device can remotely monitor the work status of the excavator100while confirming the display contents of the surrounding image of the excavator100, the information screen, or the like displayed on the remote monitoring display device, for example. The monitoring person at the external device may also be able to, for example, implement emergency stop with respect to the operation of the excavator100or to perform an intervention operation with respect to the excavator100by providing a predetermined input to the external device in the event that a problem arises in the work status of the excavator100. In this case, the excavator100may stop the actuator in response to a signal indicating emergency stop received from the external device through the communication device, to implement emergency stop with respect to the driven part such as the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like. Further, the excavator100may operate the actuator in response to a signal representing the contents of the intervention operation received from the external device through the communication device to implement the intervention operation with respect to a driven part such as the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like.

[Configuration of Excavator]

Next, the configuration of the excavator100according to the present embodiment will be described with reference toFIGS.2to7in addition toFIG.1.

FIGS.2and3are block diagrams schematically illustrating one example and another example of the configuration of the excavator100according to the present embodiment.FIG.4is a diagram illustrating an example of a configuration relating to the operation limitation of the hydraulic driving system.FIG.5is a diagram illustrating another example of a configuration relating to the operation limitation of the hydraulic driving system.FIG.6is a diagram illustrating an example of a cooling device60mounted on an excavator100according to the present embodiment.FIG.7is a diagram illustrating an example of a heat pump cycle82of an air conditioning device80mounted on the excavator100according to the present embodiment.

InFIGS.2and3, the transmission system of mechanical power is represented by a double line; the transmission system of relatively high hydraulic pressure, that is, the hydraulic oil line of a hydraulic driving system is represented by a thick solid line; the transmission system of pilot pressure, that is, the hydraulic oil line of an operation system is represented by a dashed line; and the transmission system of power and electrical signals is represented by a thin solid line.

The excavator100includes elements of each of the hydraulic driving system, the electric driving system, the power source system, the operation system, the cooling system, the user interface system, the comfort equipment system, the control system, and the like.

<Hydraulic Driving System>

The hydraulic driving system of the excavator100is a group of elements relating to the hydraulic driving of the driven parts.

The hydraulic driving system of the excavator100includes hydraulic actuators such as the traveling hydraulic motors1A and1B, a boom cylinder7, an arm cylinder8, a bucket cylinder9, and the like, for hydraulically driving each driven part of the lower traveling body1, the boom4, the arm5, the bucket6, and the like, respectively. The hydraulic driving system of the excavator100also includes a pump motor12, a main pump14, and a control valve17.

The pump motor12(an example of a motor) is a power source for the hydraulic driving system. The pump motor12is, for example, an IPM (Interior Permanent Magnet) motor. The pump motor12is connected to a power storage device19via an inverter18. The pump motor12is powered by three-phase AC power supplied from the power storage device19via the inverter18to drive the main pump14and a pilot pump15. The drive control of the pump motor12may be performed by an inverter18under the control of a controller30B, which will be described later.

The main pump14(an example of a hydraulic pump) suctions the hydraulic oil from a hydraulic oil tank T and discharges the hydraulic oil to a high pressure hydraulic line16to supply the hydraulic oil to the control valve17through the high pressure hydraulic line16. The main pump14is driven by the pump motor12as described above. The main pump14is, for example, a variable capacity hydraulic pump, and a regulator (not illustrated) controls the angle (tilt angle) of the swash plate under the control of a controller30A, which will be described later. Accordingly, the main pump14can adjust the stroke length of the piston and adjust the discharge flow rate (discharge pressure).

The control valve17(an example of a hydraulic control device) controls the hydraulic driving system in response to an operation instruction corresponding to an operator's operation or an automatic operation function. The control valve17is, as described above, connected to the main pump14via the high pressure hydraulic line16and is configured to selectively supply hydraulic oil supplied from the main pump14to a plurality of hydraulic actuators. For example, the control valve17is a valve part which includes a plurality of control valves (directional switching valves) for controlling the flow and flow direction of hydraulic oil supplied from the main pump14to each of the hydraulic actuators. The hydraulic oil supplied from the main pump14and flowing through the control valve17or the hydraulic actuator is discharged from the control valve17to the hydraulic oil tank T.

<Electric Driving System>

The electric driving system of the excavator100is a group of elements relating to the electric driving of the motor (power source) and driven parts of the excavator100.

As illustrated inFIGS.2and3, the electric driving system of the excavator100includes the pump motor12, a sensor12s, and the inverter18.

As described above, the electric driving system of the excavator100may include an electric actuator for driving the driven part, an inverter for driving the electric actuator, or the like, when some of or all of the driven parts are electrically driven.

The sensor12sincludes a current sensor12s1, a voltage sensor12s2, and a rotation state sensor12s3.

The current sensor12s1detects the current of each of the three phases (U, V, and W phases) of the pump motor12. The current sensor12s1is provided, for example, in a power path between the pump motor12and the inverter18. The detection signal corresponding to the current of each of the three phases of the pump motor12detected by the current sensor12s1is taken directly into the inverter18through the communication line. The detection signal may also be taken into controller30B through communication line and input to the inverter18via the controller30B.

The voltage sensor12s2detects the applied voltage of each of the three phases of the pump motor12. The voltage sensor12s2is provided, for example, in the power path between the pump motor12and the inverter18. The detection signal corresponding to the applied voltage of each of the three phases of the pump motor12detected by the voltage sensor12s2is taken directly into the inverter18through the communication line. The detection signal may also be taken into the controller30B through the communication line and input to the inverter18via the controller30B.

The rotation state sensor12s3detects the rotation state of the pump motor12. The rotation state of the pump motor12includes, for example, a rotation position (rotation angle), a revolution speed, and the like. The rotation state sensor12s3is, for example, a rotary encoder or a resolver. The detection signal corresponding to the rotation state of the pump motor12detected by the rotation state sensor12s3is taken directly into the inverter18through the communication line. The detection signal may also be taken into controller30B via communication line and input to the inverter18via controller30B.

The inverter18drives and controls the pump motor12under the control of the controller30B. The inverter18includes, for example, a conversion circuit for converting DC power to three-phase AC power or for converting three-phase AC power to DC power, a driving circuit for switching the conversion circuit, and a control circuit for outputting control signals for defining the operation of the driving circuit. The control signal is, for example, a PWM (Pulse Width Modulation) signal.

The control circuit of the inverter18performs drive control of the pump motor12while identifying the operation state of the pump motor12. For example, the control circuit of the inverter18identifies the operation state of the pump motor12based on the detection signal of the rotation state sensor12s3. The control circuit of the inverter18may sequentially identify the operation state of the pump motor12by estimating the rotation angle of the rotation axis of the pump motor12or the like, based on the detection signal of the current sensor12s1and the detection signal of the voltage sensor12s2(or a voltage instruction value generated in the control process).

At least one of the driving circuit or the control circuit of the inverter18may be provided outside the inverter18.

<Power Supply>

The power supply system of the excavator100is a group of elements for supplying power to various electrical devices.

As illustrated inFIGS.2and3, the power supply system of the excavator100includes the power storage device19, a DC-DC converter44, a battery46, an in-vehicle charger70, and a charging port72.

The power storage device19is an energy source for driving an actuator of the excavator100. The power storage device19is connected to an external commercial power supply by a predetermined cable (hereinafter referred to as “charging cable”), thereby being charged (power storage), and supplying the charged (stored) power to the pump motor12. The power storage device19is, for example, a lithium ion battery and has a relatively high output voltage (e.g., several hundred volts).

A power converting device may be provided between the power storage device19and the pump motor12for boosting the output voltage of the power storage device19and applying the output voltage to the pump motor12. As described above, when some of or all of the driven parts are electrically driven, the power of the power storage device19is supplied to an electric actuator that electrically drives the driven part instead of or in addition to the pump motor12.

The DC-DC converter44is provided, for example, in the upper turning body3to decrease DC power of a very high voltage output from the power storage device19to a predetermined voltage (e.g., approximately 24 volts), and output the decreased voltage. The output power of the DC-DC converter44is supplied to the battery46for charging (power storage) the battery46, or is supplied to an electric device (hereinafter referred to as “low voltage device”) that is powered by the battery46. The low voltage devices include, for example, various controllers (such as controllers30A to30E) included in a control device30. Examples of the low voltage device are, for example, a water pump64(W/P), the air conditioning device80, a fan90, and the like, which will be discussed later.

For example, as illustrated inFIG.2, one DC-DC converter44is mounted on the excavator100.

For example, as illustrated inFIG.3, the DC-DC converter44may include a plurality of DC-DC converters (in this example, two DC-DC converters44A and44B) connected in parallel. This allows the plurality of the DC-DC converters44A and44B to share the operation of outputting the current required by the low voltage device. As a result, the plurality of the DC-DC converters44A and44B will each have a relatively small current capacity, that is, a relatively small maximum value of the output current, and will thus have a relatively small external size. Therefore, it is possible to improve the degree of freedom of arrangement when mounting the DC-DC converters44A and44B in the upper turning body3. Further, even if one of the plurality of the DC-DC converters44A and44B is unable to supply power due to an abnormality or the like, the power supply from the other converter can be continued.

Note that the DC-DC converter44may be replaced by an alternator. In this case, the alternator may be provided in the upper turning body3and generate power by the power of the pump motor12. As with the DC-DC converter44, the alternator's generating power is supplied to the battery46for charging (power storage) the battery46, or to the low voltage device such as controllers30A to30E.

The battery46is provided in the upper turning body3and has a relatively low output voltage (e.g., 24 volts). The battery46supplies power to low voltage devices, other than those in the electric driving system that require relatively high power. The battery46may be, for example, a lead-acid battery or a lithium-ion battery, and may be charged with the output power of the DC-DC converter44as described above.

The in-vehicle charger70converts single-phase AC power having a relatively low voltage (e.g., 100 volts or 200 volts) supplied from an external power source through a charging port72A, which will be described later, to DC power, and outputs the power to the power storage device19to charge the power storage device19.

The charging port72is provided, for example, on the side surface of the upper turning body3or the like, and is connected by inserting the leading end of the charging cable extending from an external power source. The charging port72includes charging ports72A and72B.

The charging port72A is configured to be connectable with a charging cable extending from an external power supply (e.g., a commercial power supply) capable of supplying, for example, single-phase AC power of a relatively low voltage. The charging port72A is connected to the in-vehicle charger70by a power line (wire harness) and supplies power supplied from an external power source to the power storage device19through the in-vehicle charger70. This achieves what is referred to as normal charging of the power storage device19.

The charging port72B is connected with a charging cable extending from an external power source capable of supplying, for example, DC power of relatively high voltage (e.g., 400 volts). The charging port72B is connected directly to the power storage device19by a power line (wire harness) to directly provide DC power to the power storage device19from an external power source. This results in what is referred to as rapid charging of the power storage device19.

<Operation System>

The operation system of the excavator100is a group of elements related to the operation of the driven part.

As illustrated inFIGS.2and3, the operation system of the excavator100includes the pilot pump15, the operation device26, and a hydraulic control valve31. As illustrated inFIG.4, the operation system of the excavator100includes a gate lock valve25V1, a gate lock switch25SW, and a relay25R. As illustrated inFIG.5, the operation system of the excavator100may include a switching valve25V2in addition to the relay25R.

The pilot pump15supplies pilot pressure to various hydraulic devices (e.g., the hydraulic control valve31) mounted to the excavator100via the pilot line25. Thus, the hydraulic control valve31, under the control of the controller30A, can supply pilot pressure to the control valve17according to the operation contents (for example, the operation amount or the operation direction) with respect to the operation device26. Accordingly, the controller30A and the hydraulic control valve31can implement the operation of a driven part (the hydraulic actuator) according to the operation content with respect to the operation device26by the operator. The hydraulic control valve31, under the control of the controller30A, can supply pilot pressure to the control valve17according to the contents of the remote operation specified by the remote operation signal. The hydraulic control valve31, under the control of the controller30A, is also capable of supplying pilot pressure to the control valve17in accordance with an operation instruction corresponding to an automatic operation function. The pilot pump15is, for example, a fixed capacitive hydraulic pump, and is driven by the pump motor12as described above.

Note that the pilot pump15may be omitted. In this case, the hydraulic devices such as the hydraulic control valve31may be supplied with hydraulic oil having pressure reduced to a predetermined pilot pressure, which is discharged from the main pump14via a pressure reducing valve or the like.

The operation device26is provided within reach of an operator in the operator's seat of the cabin10and is used by the operator to operate the respective driven parts (i.e., the left and right crawlers1C of the lower traveling body1, the upper turning body3, the boom4, the arm5, the bucket6, and the like). That is, the operation device26is used by the operator to operate actuators (e.g., the traveling hydraulic motors1A and1B, the boom cylinder7, the arm cylinder8, the bucket cylinder9, and the like) that drive the respective driven parts. For example, as illustrated inFIGS.2and3, the operation device26is electric and outputs an electrical signal (hereinafter, “operation signal”) according to the operation contents by the operator. The operation signal output from the operation device26is loaded into the controller30A. Accordingly, the control device30including the controller30A can control the hydraulic control valve31or the like to control the operation of the driven part (the actuator) of the excavator100in accordance with the operation instructions corresponding to the operation contents of the operator and the automatic operation function.

The operation device26includes, for example, levers26A to26C. The lever26A may be configured to receive an operation relating to each of the arm5(the arm cylinder8) and the upper turning body3(turning motion), according to the operation in the front-rear direction and the left-right direction, for example. The lever26B may be configured to receive an operation relating to each of the boom4(the boom cylinder7) and the bucket6(the bucket cylinder9), according to the operation in the front-rear direction and the left-right direction, for example. The lever26C may be configured to receive an operation relating to the lower traveling body1(the crawler1C), for example.

When the control valve17is configured by an electromagnetic pilot-type hydraulic control valve (directional switching valve), the operation signal of the electric operation device26may be directly input to the control valve17, and the respective hydraulic control valves may operate according to the operation contents of the operation device26. The operation device26may be a hydraulic pilot type which outputs pilot pressure according to the operation contents. In this case, the pilot pressure according to the operation is supplied to the control valve17.

The hydraulic control valve31outputs a predetermined pilot pressure by using hydraulic oil supplied from the pilot pump15through the pilot line25, under the control of the controller30A. The pilot line on the secondary side of the hydraulic control valve31is connected to the control valve17, and the pilot pressure output from the hydraulic control valve31is supplied to the control valve17.

The gate lock valve25V1is a switching valve provided on the pilot line25. The gate lock valve25V1is, for example, an electromagnetic solenoid valve. In a non-energized state (the state inFIGS.4and5), the gate lock valve25V1maintains the spool in the right-hand position in the drawing by elastic force and sets the pilot line25to be in a non-communicating state. In this case, the gate lock valve25V1discharges the hydraulic oil of the pilot line25on the downstream side to the hydraulic oil tank T. On the other hand, the gate lock valve25V1, when energized (in an energized state), moves the spool leftward against the elastic force by the function of the electromagnetic solenoid to set the pilot line25in a communicating state. In this case, the gate lock valve25V1supplies the hydraulic oil of the pilot pump15to the downstream side.

The gate lock switch25SW is provided on a power line between the battery46and the gate lock valve25V1(electromagnetic solenoid). In the off state, the gate lock switch25SW opens the power line to set the gate lock valve25V1to be in a non-energized state, and in the on state, the gate lock switch25SW closes the power line to set the gate lock valve25V1to be in an energized state.

The gate lock switch25SW is turned on and off according to the operation state of the gate lock lever inside the cabin10. The gate lock switch25SW is, for example, a limit switch that operates in conjunction with the operation of the gate lock lever.

The gate lock switch25SW is turned off when the gate lock lever is in a state corresponding to a pulled-up state of the gate bar, i.e., in an operation state corresponding to a state in which the operation seat of the cabin10is open such that an operator can enter or exit the cabin10. Thus, when the gate bar is in a raised state, the gate lock valve25V1maintains the pilot line25in a non-communicating state. Therefore, the gate lock switch25SW can operate the gate lock valve25V1such that pilot pressure is not supplied to the hydraulic control valve31, in accordance with a situation in which the operator of the cabin10has no intention to operate the excavator, a situation in which the operator is absent from the cabin10, or the like. On the other hand, the gate lock switch25SW is turned on when the gate bar is lowered, i.e., in an operation state corresponding to a state in which the operation seat of the cabin10is closed such that an operator cannot enter or exit the cabin10. This allows the gate lock switch25SW to operate the gate lock valve25V1such that pilot pressure is supplied to the hydraulic control valve31, in accordance with a situation in which the operator of the cabin10intends to operate the excavator.

The relay25R is used to cut off the pilot line25(to be in a non-communicating state) regardless of the operation state of the gate lock lever, i.e., the state of the gate lock switch25SW.

For example, as illustrated inFIG.4, the relay25R is positioned on a power line between the battery46and the gate lock valve25V1(electromagnetic solenoid). In this case, the relay25R is a normally closed type, and is opened when energized by a control current input from the controller30A. Thus, by energizing the relay25R and opening the relay25R, the controller30A can cause the gate lock valve25V1to be in a non-energized state, and cause the pilot line25to transition to a non-communicating state, even when the gate lock switch25SW is on. Therefore, the control device30(the controller30A) can stop the operation of the driven part (hydraulic actuator).

For example, as illustrated inFIG.5, the relay25R may be provided on a power line between the battery46and the switching valve25V2(electromagnetic solenoid). In this case, the relay25R is a normally open type, and is closed when energized by a control current input from the controller30A.

The switching valve25V2is provided on the pilot line25. For example, as illustrated inFIG.5, the switching valve25V2may be provided downstream of the gate lock valve25V1of the pilot line25or upstream of the gate lock valve25V1. The switching valve25V2is, for example, an electromagnetic solenoid valve. Similar to the gate lock valve25V1, the switching valve25V2maintains the spool in the right-hand position in the drawing by elastic force in the non-energized state (the state illustrated inFIG.5) and causes the pilot line25is to be in a communicating state. On the other hand, the switching valve25V2, when energized, moves the spool leftward against the elastic force, by the function of the electromagnetic solenoid, to cause the pilot line25to be in a non-communicating state.

When the coil of the relay25R is not energized (in a non-energized state), the relay25R is opened so that the switching valve25V2maintains the pilot line25in a communicating state. On the other hand, when the coil of the relay25R is energized by the controller30A, the relay25R is closed so that the switching valve25V2maintains the pilot line25in a non-communicating state. This allows the control device (the controller30A) to cause the switching valve25V2to transition to a non-communicating state even when the gate lock valve25V1is in a communicating state. Therefore, the control device (the controller30A) can stop the operation of the driven part (hydraulic actuator).

The relay25R and the switching valve25V2may be omitted. In this case, the control device30may control the pilot pressure output from the hydraulic control valve31, for example, to limit the operation of the driven part (hydraulic actuator).

<Cooling System>

The cooling system of the excavator100is a group of elements for cooling the elements that generate heat in association with the operation of the excavator100.

As illustrated inFIG.6, the cooling system of the excavator100includes a cooling device60and a fan90.

The cooling device60cools the devices of the electric driving system in the excavator100and the devices of the power supply system having a relatively high voltage. For example, as illustrated inFIG.6, the device to be cooled by the cooling device60includes the pump motor12, the inverter18, the power storage device19, the DC-DC converter44, the in-vehicle charger70, and the like.

Note that, as long as the necessary conditions relating to the cooling performance for each of the plurality of cooling targets are satisfied, the connection mode in a refrigerant circuit66of the cooling target may be optional, wherein the refrigerant circuit66is configured to allow a refrigerant to pass therearound or therein. That is, as long as the necessary conditions relating to the cooling performance for each of the plurality of cooling targets are satisfied, some of or all of the plurality of cooling targets cooled by the refrigerant circuit66may be connected in series or some of or all of the plurality of cooling targets cooled by the refrigerant circuit66may be connected in parallel. Further, as long as the necessary conditions relating to the cooling performance for each of the plurality of cooling targets are satisfied, the order in which the plurality of cooling targets are arranged starting from a radiator62in the refrigerant circuit66is optional.

The cooling device60includes the radiator62, the water pump64, and the refrigerant circuit66.

The radiator62cools the refrigerant (e.g., cooling water) in the refrigerant circuit66. Specifically, the radiator62allows heat exchange between the ambient air and the refrigerant to cool the refrigerant.

The water pump64circulates the refrigerant within the refrigerant circuit66. The water pump64operates, for example, by power supplied from the DC-DC converter44or the battery46.

The refrigerant circuit66(an example of a circulation circuit) includes refrigerant flow paths66A,66B,66C,66C1,66C2,66D,66D1,66D2,66E, and66F.

The refrigerant flow path66A connects the water pump64and the power storage device19to allow the refrigerant discharged from the water pump64to flow into the refrigerant flow path inside or around the power storage device19. Thus, the cooling device60can cool the power storage device19with a refrigerant. The refrigerant flowing through the refrigerant flow path inside or around of the power storage device19flows out to the refrigerant flow path66B.

The refrigerant flow paths66B,66B1, and66B2connect the power storage device19to the inverter18and the DC-DC converter44. The refrigerant flow paths66B,66B1, and66B2allow refrigerant flowing from the refrigerant flow paths inside or around the power storage device19to flow into the refrigerant flow paths inside or around the inverter18and the DC-DC converter44. Specifically, the refrigerant flow path66B has one end connected to the power storage device19and has the other end branching into the refrigerant flow paths66B1and66B2, which are connected to the inverter18and the DC-DC converter44, respectively. The refrigerant flow paths66B1and66B2allow the refrigerant to flow into the refrigerant flow paths inside or around the inverter18and the DC-DC converter44. This allows the cooling device60to cool the inverter18and the DC-DC converter44with the refrigerant. The refrigerant flowing through the refrigerant flow path inside or around the inverter18flows out to the refrigerant flow path66C1. Further, the refrigerant flowing through the refrigerant flow path inside or around the DC-DC converter44flows out to the refrigerant flow path66C2.

The refrigerant flow paths66C,66C1, and66C2connect the inverter18and the DC-DC converter44to the pump motor12. The refrigerant flow paths66C,66C1, and66C2allow the refrigerant that flows out of the refrigerant flow paths inside or around the inverter18and the DC-DC converter44into the refrigerant flow paths inside or around the pump motor12. Specifically, the refrigerant flow paths66C1and66C2have one end connected to the inverter18and the DC-DC converter44, respectively, which merge with one end of the refrigerant flow path66C, and the other end of the refrigerant flow path66C is connected to the pump motor12. Thus, the cooling device60can cool the pump motor12with a refrigerant. The refrigerant flowing through the refrigerant flow path inside or around the pump motor12flows out into the refrigerant flow path66D.

When a power converting device is provided between the power storage device19and the pump motor12, the power converting device may be cooled by the cooling device60. In this case, for example, in the refrigerant circuit66, the power converting device may be arranged in parallel with the inverter18and the DC-DC converter44and cooled by the refrigerant flowing out of the power storage device19. The DC-DC converter44may be air-cooled. In this case, the refrigerant flow paths66B2and66C2are omitted. At least a portion of the inverter18and the DC-DC converter44and the like may be arranged in series in the refrigerant circuit66.

The refrigerant flow path66D connects the pump motor12and the in-vehicle charger70and causes the refrigerant flowing from the refrigerant flow path inside or around the pump motor12to flow into the refrigerant flow path inside or around the in-vehicle charger70. Accordingly, the cooling device60can cool the in-vehicle charger70by using a refrigerant. The refrigerant flowing through the refrigerant flow path inside or around the in-vehicle charger70flows out into the refrigerant flow path66E.

The refrigerant flow path66E connects the in-vehicle charger70and the radiator62and supplies the refrigerant flowing out of the refrigerant flow path inside or around the in-vehicle charger70, to the radiator62. Accordingly, the refrigerant circuit66cools various devices of the electric driving system or the power supply system and cools the refrigerant whose temperature is raised, by the radiator62. Then, the refrigerant circuit66can cause various devices of the electric driving system or the power supply system to return a coolable state again.

The refrigerant flow path66F connects the radiator62and the water pump64and supplies the refrigerant cooled by the radiator62to the water pump64. This allows the water pump64to discharge the refrigerant cooled by the radiator62into the refrigerant flow path66A and circulate through the refrigerant circuit66.

The fan90operates under the control of the control device30(e.g., the controller30A) and blows air toward a predetermined device (hereinafter referred to as a “heat exchanger”) that exchanges heat with air. The fan90operates, for example, by power supplied from the DC-DC converter44or the battery46.

The fan90may, for example, blow air toward the radiator62and cool the radiator62, as illustrated inFIG.6. Accordingly, around the radiator62, air capable of exchanging heat with the refrigerant passing inside the radiator62, is sequentially supplied, and the degree of cooling of the refrigerant by the radiator62can be increased.

The fan90may be a single fan or a plurality of fans as described below. That is, the fan90may be configured in any number provided that the required degree of heat exchange (degree of cooling or degree of heating) by the heat exchanger can be secured.

The cooling system of the excavator100may include an oil cooler for cooling the hydraulic oil used in the hydraulic driving system (high pressure hydraulic line) or the operation system (pilot line). The oil cooler may be provided, for example, in a return oil path between the control valve17and the hydraulic oil tank T to perform heat exchange between ambient air and the hydraulic oil flowing therein, to cool the hydraulic oil. In this case, the fan90may blow air toward the oil cooler and the oil cooler may be cooled. As a result, the surroundings of the oil cooler is continuously supplied with air which is capable of exchanging heat with the hydraulic oil flowing in the oil cooler, thereby increasing the degree of cooling of the hydraulic oil by the oil cooler. In this case, the same fan90, i.e., the common fan90may serve as the fan90for blowing air to the radiator62and the fan90for blowing air to the oil cooler, or different fans90may be used for these purposes.

<User Interface System>

The user interface system of the excavator100is a group of elements relating to the exchange of information with the user.

As illustrated inFIGS.2and3, the user interface system includes an output device50and an input device52.

The output device50outputs various kinds of information to the user under the control of the control device30(e.g., the controller30A). For example, the output device50is provided within the cabin10and includes an output device for outputting various kinds of information to a user (e.g., an operator) within the cabin10. For example, the output device50may be provided outside the cabin10and include an output device for outputting various kinds of information to a user around the excavator100(e.g., a worker or a supervisor around the excavator100).

The output device50includes, for example, a display device, a lighting device, or the like, that outputs (reports) information to the user in a visual manner. The display device may display various information images under the control of controller30A. The display device may be, for example, a liquid crystal display, an organic electroluminescence display, or the like. The lighting device may be, for example, a warning lamp or the like.

The output device50also includes, for example, a sound output device for outputting information in an auditory manner to a user. The sound output device may be, for example, a buzzer or a speaker.

The input device52receives various inputs from a user. For example, the input device52is provided within the cabin10and includes an input device for receiving various inputs from a user (e.g., an operator) within the cabin10. For example, the input device52may be provided outside the cabin10and include an input device for receiving various inputs from a user outside the cabin10(e.g., a worker or a supervisor around the excavator100).

The input device52may include, for example, an operation input device that receives the user's operation input. The operation input device includes, for example, buttons, toggles, levers, touch panels, touch pads, and the like. The input device52may also include, for example, a sound input device for receiving sound inputs from an operator or a gesture input device for receiving gesture inputs from an operator. The sound input device includes, for example, a microphone that acquires the voice sound of a user. The gesture input device includes, for example, a camera capable of capturing a user's gesture. A signal corresponding to an input from an operator received by the input device52is loaded into the control device30(e.g., the controller30A).

<Comfort Equipment>

The comfort equipment of the excavator100is a group of elements relating to the comfort equipment of the user (operator) within the cabin10.

As illustrated inFIG.7, the comfort equipment system of the excavator100includes the air conditioning device80. Further, as illustrated inFIG.7, the comfort equipment system of the excavator100includes the fan90.

The air conditioning device80adjusts the condition of the air in the cabin10, specifically the temperature and humidity of the air. The air conditioning device80operates, for example, by power supplied from the DC-DC converter44or the battery46. The air conditioning device80is, for example, a heat pump type for both cooling and heating, and includes a heat pump cycle82.

The air conditioning device80may include, for example, a freezing cycle and a heater for heating, in place of the heat pump cycle82. A heater for heating includes, for example, a positive temperature coefficient (PTC) heater, a combustion type heater, and the like.

As illustrated inFIG.7, the heat pump cycle82includes a compressor82A, a condenser82B, an expansion valve82C, and an evaporator82D.

The arrows inFIG.7represent the flow of the refrigerant during the cooling operation of the air conditioning device80, and the flow of the refrigerant during the heating operation of the air conditioning device80will be in the reversed direction.

The compressor82A compresses the refrigerant in the heat pump cycle82. The compressor82A includes, for example, an internal motor and an inverter circuit for driving the motor, and is electrically driven by power supplied from the battery46or the DC-DC converter44. The refrigerant compressed by the compressor82A is delivered to the condenser82B during the cooling operation of the air conditioning device80, and is delivered to the evaporator82D during the heating operation of the air conditioning device80.

The compressor82A may be configured to be driven by power supplied directly from the power storage device19. The compressor82A may also be configured to be mechanically driven by the pump motor12.

The condenser82B is compressed by the compressor82A during the cooling operation of the air conditioning device80to cool the refrigerant having relatively high temperature and an elevated gas state. Specifically, the condenser82B releases heat of the refrigerant to the outside air by heat exchange between the refrigerant that is passing inside, and the outside air, thereby cooling the refrigerant. The refrigerant cooled by the condenser82B changes to a liquid state.

In the heating operation of the air conditioning device80, the condenser82B draws heat from the outside air by heat exchange between the refrigerant that is passing inside, and the outside air, thereby increasing the temperature of the refrigerant which is depressurized through the expansion valve82C and lowered to a relatively low temperature.

The expansion valve82C rapidly reduces the pressure of the refrigerant passing therethrough and lowers the temperature of the refrigerant. The expansion valve82C rapidly reduces the pressure of the refrigerant that is in a liquid state and a high pressure state, delivered from the condenser82B during the cooling operation of the air conditioning device80, thereby lowering the temperature of the refrigerant. The expansion valve82C rapidly reduces the pressure of the refrigerant that is in a liquid state and a high pressure state, delivered from the evaporator82D during the heating operation of the air conditioning device80, thereby lowering the temperature of the refrigerant.

The evaporator82D exchanges heat between the refrigerant passing inside and the air delivered from the air conditioning device80into the cabin10. The evaporator82D cools the air delivered into the cabin10during the cooling operation of the air conditioning device80, in a manner such that the refrigerant, which has a relatively low temperature (vapor-liquid mixed state) and which is delivered from the expansion valve82C, draws the heat from the air. The evaporator82D heats the air delivered into the cabin10during the heating operation of the air conditioning device80, in a manner such that the air draws heat from the refrigerant, which has a relatively high temperature (gas state) and which is delivered from the compressor82A.

The fan90, for example, may blow air toward the condenser82B to cool or heat the condenser82B, as illustrated inFIG.7. Accordingly, the surroundings of the condenser82B is continuously supplied with air capable of heat exchange with the refrigerant passing inside, thereby increasing the degree of cooling or heating of the refrigerant by the condenser82B.

<Control System>

The control system of the excavator100is a group of elements relating to the various kinds of control with respect to the excavator100.

As illustrated inFIGS.2and3, the control system of the excavator100includes the control device30. The control system of the excavator100also includes a surrounding information acquiring device40, a sensor48, and temperature sensors54and56.

The control device30includes the controllers30A to30E.

The functions of controllers30B to30E may be integrated into the controller30A. That is, the various functions implemented by the control device30may be implemented by a single controller or may be distributed among two or more controllers suitably set.

The functions of each of the controllers30A to30E may be implemented with any hardware or any combination of hardware and software. For example, the controllers30A to30E are each mainly configured by a computer including a CPU (Central Processing Unit), a memory device such as a RAM (Random Access Memory), an auxiliary storage device such as a ROM (Read Only Memory), an interface device functioning as an interface with outside devices, and the like. The controllers30A to30E, for example, implement various functions by loading a program installed in an auxiliary storage device into a memory device and executing the program on the CPU.

The controller30A cooperates with various controllers included in the control device30including the controllers30B to30E, to perform drive control of the excavator100.

The controller30A, for example, outputs a control instruction to the hydraulic control valve31in response to an operation signal input from the operation device26and outputs pilot pressure from the hydraulic control valve31according to the operation contents of the operation device26. Thus, the controller30A can implement the operation of the driven part (hydraulic actuator) of the excavator100corresponding to the operation contents of the electric operation device26.

Further, when the excavator100is remotely operated, for example, the controller30A may implement control relating to the remote operation. Specifically, the controller30A may output a control instruction to the hydraulic control valve31and output pilot pressure from the hydraulic control valve31according to the contents of the remote operation. Accordingly, the controller30A can implement the operation of the driven part (hydraulic actuator) of the excavator100corresponding to the contents of the remote operation.

The controller30A may, for example, implement control relating to the automatic operation function. Specifically, the controller30A may output a control instruction to the hydraulic control valve31and apply pilot pressure, in accordance with an operation instruction corresponding to an automatic operation function, from the hydraulic control valve31to the control valve17. Accordingly, the controller30A can implement the operation of the driven part (the hydraulic actuator) of the excavator100corresponding to the automatic operation function.

Further, the controller30A may control the operation of the entire excavator100(various devices mounted in the excavator100) in an integrated manner based on two-way communication with various controllers such as the controllers30B to30E.

The controller30B implements control relating to the electric driving system based on various kinds of information input from the controller30A (for example, a control instruction including an operation signal of the operation device26).

The controller30B, for example, outputs a control instruction to the inverter18and implements drive control of the pump motor12.

As described above, when a power converting device is provided between the power storage device19and the pump motor12, the controller30B may, for example, output a control instruction to the power converting device to control the operation of the power converting device.

The controller30C implements control relating to the surrounding monitoring function of the excavator100.

The controller30C detects a predetermined object around the excavator100(hereinafter referred to as a “monitored object”) and estimates the position of the monitored object based on, for example, data regarding the status of the three-dimensional space around the excavator100taken from the surrounding information acquiring device40. The monitored object may include, for example, a person. The monitored object may also include, for example, other work vehicles or other work machines. The monitored object may also include, for example, a utility pole, a pylon, a fence, a work site material, and the like. Data regarding the status of the three-dimensional space around the excavator100includes, for example, detection data regarding an object around the excavator100and the position of the object.

The controller30C, for example, outputs a warning to a user in the cabin10and to the surroundings of the excavator100through an output device50(e.g., a display device, a sound output device, or the like) when the monitored object is detected within a predetermined monitoring range. The monitoring range is suitably set, for example, as a range around the excavator100that is a relatively close distance from the excavator100.

The controller30C may, for example, limit the operation of a driven part (actuator) of the excavator100when the monitored object is detected within a predetermined monitoring range.

Limitations on the operation of driven parts include, for example, stopping the operation of driven parts. The controller30C may forcibly stop the driven part (hydraulic actuator) by, for example, outputting a request signal to the controller30A and opening the relay25R described above. The controller30C may forcibly stop the operation of the driven part (hydraulic actuator) by outputting a request signal to the controller30A and disabling the operator's operation or operation instructions.

Further, limitations on the operation of the driven part includes, for example, slowing down of the operation of the driven part. The controller30C may, for example, output a request signal to the controller30A, relatively reduce the pilot pressure output from the hydraulic control valve31to the control valve17, and slow down the operation of the driven part (the hydraulic actuator) with respect to the operator's operation and operation instructions.

The controller30D implements control relating to the power storage device19.

The controller30D controls, for example, the charging of the power storage device19.

The controller30D monitors various states (e.g., the current state, the voltage state, the temperature state, the charge state, the deterioration state, presence or absence of abnormality, and the like) of the power storage device19based on the output of various sensors built into the power storage device19, for example.

The controller30E implements control relating to the DC-DC converter44.

The controller30E implements control relating to, for example, the operation of the DC-DC converter44.

The controller30E monitors various states (e.g., the current state, the voltage state, the temperature state, etc.) of the DC-DC converter44, for example.

The surrounding information acquiring device40outputs information concerning the status of the three-dimensional space around the excavator100. The surrounding information acquiring device40may include, for example, an ultrasonic sensor, a millimeter wave radar, a monocular camera, a stereo camera, a depth camera, LIDAR (Light Detection and Ranging), a distance image sensor, an infrared sensor, and the like. The output information of the surrounding information acquiring device40is loaded into the controller30C.

The surrounding monitoring function of the excavator100may be omitted. In this case, the controller30C or the surrounding information acquiring device40may be omitted.

The sensor48measures the state of the power supplied to the low voltage load from the DC-DC converter44and the battery46. For example, the sensor48may include a current sensor that measures the current supplied to the low voltage load from the DC-DC converter44or the battery46or a voltage sensor that measures the voltage.

The temperature sensor54measures (detects) the temperature of the device of the electric driving system to be cooled by the cooling device60, which will be described later. The temperature sensor54includes, for example, a temperature sensor that detects the temperature of the pump motor12. The temperature sensor54also includes a temperature sensor that detects the temperature of the inverter18. The temperature sensor54also includes, for example, a temperature sensor that detects the temperature of the power storage device19. The temperature sensor54also includes, for example, a temperature sensor that detects the temperature of the DC-DC converter44. The temperature sensor54also includes, for example, a temperature sensor that detects the temperature of the in-vehicle charger70. The detection signal of the temperature sensor54is incorporated into the controller30A, for example. Thus, the controller30A can identify the temperature state of devices in the electric driving system.

If a power conversion device is provided between the power storage device19and the pump motor12, the temperature sensor may include a temperature sensor for identifying the temperature state of the power conversion device.

The temperature sensor56measures (detects) the indoor temperature of the cabin10. The detection signal from the temperature sensor56is incorporated into the controller30A, for example. Thus, the controller30A can identify the temperature state in the interior of the cabin10.

[Arrangement Structure of Various Devices in the Upper Turning Body]

Next, the arrangement structure of various devices in the upper turning body3will be described with reference toFIG.8.

FIG.8is a top view illustrating an example of the arrangement structure of various devices of the upper turning body3.FIG.9is a perspective view illustrating an example of a maintenance door3D of the upper turning body3. InFIG.8, a house portion3H of the upper turning body3(seeFIG.9) is omitted to expose various devices of the upper turning body3.

As illustrated inFIG.8, in this example, the power storage device19is mounted in a range extending from the front portion to the center portion in the front-rear direction on the right side of the upper turning body3.

The pump motor12, the main pump14, the pilot pump15, the control valve17, and the inverter18are provided in a range extending from the center portion to the right end portion in the left-right direction at the rear portion of the upper turning body3.

The pump motor12and the inverter18are arranged integrally at the center portion in the left-right direction at the rear portion of the upper turning body3. The pump motor12and inverter18are also arranged in a manner that the pump motor12has the axis of rotation thereof aligned with the left-right direction and has the output axis thereof extending to the right. For example, the pump motor12is mounted to the bottom portion3B (turning frame) of the upper turning body3via a mount member. Specifically, the pump motor12may be positioned in relative proximity to the bottom portion3B such that the positions of the main pump14and the pilot pump15, which are coupled in a manner as to be machine-driven, are as low as possible. This allows the position of the main pump14to be positioned lower than the liquid level inside the hydraulic oil tank T. Therefore, it is possible to reduce the occurrence of air entrainment in the main pump14.

The main pump14and the pilot pump15are positioned adjacent the right side of the pump motor12in a manner such that the input shaft thereof is coupled to the output shaft of the pump motor12. The main pump14and the pilot pump15are mounted on the bottom portion3B via the pump motor12, for example, by being coupled to the pump motor12.

The control valve17is arranged at the center portion in the left-right direction at the rear portion of the upper turning body3and above the pump motor12. For example, the pump motor12and the main pump14are positioned at a relatively low position in the space between the bottom portion3B and the house portion3H of the upper turning body3, and the control valve17is positioned at a relatively high position in that space. Specifically, a stand17MT which is provided so as straddle the pump motor12in the front-rear direction, is mounted to the bottom portion3B. The control valve17is mounted on the stand17MT, and is mounted to the bottom portion3B via the stand17MT.

Note that the control valve17may be arranged on the main pump14or the pilot pump. The control valve17may also be positioned in the left-right direction so as to straddle between the pump motor12and the main pump14or the pilot pump15.

The turning hydraulic motor2A is mounted at the center of the upper turning body3.

The hydraulic oil tank T is arranged in the space between the turning hydraulic motor2A and the pump motor12and the control valve17in the front-rear direction. The hydraulic oil tank T is mounted to the bottom portion3B, either directly or via a bracket or the like.

The radiator62, the condenser82B, and the fan90are arranged on the left side of the rear of the upper turning body3, i.e., to the left of the pump motor12, the main pump14, and the control valve17.

The radiator62is arranged so that the front-rear direction is substantially in the longitudinal direction (the width direction) and the left-right direction is substantially in the shorter direction (the thickness direction), while standing substantially perpendicular with respect to the bottom portion3B. The term “substantially” is used with the intension, for example, to allow manufacturing errors in the excavator100or the device mounted in the excavator100. The term “substantially” is used in the same manner in the following. Thus, the radiator62can perform heat exchange by introducing air between the fins of the core and passing air in the left-right direction (the shorter direction). The radiator62is attached to the bottom portion3B, for example, via a mount member.

The condenser82B is positioned adjacent to the left side of the radiator62. The condenser82B is arranged in series with the radiator62with respect to the air flow. That is, similar to the radiator62, the condenser82B is arranged so that the front-rear direction is substantially in the longitudinal direction (the width direction) and the left-right direction is in the shorter direction (the thickness direction), while standing substantially perpendicular with respect to the bottom portion3B. The condenser82B is mounted on the bottom portion3B via the radiator62, for example, by being attached to the radiator62, either directly or via a bracket or the like.

Note that other heat exchangers may be arranged adjacent the radiator62and the condenser82B. For example, an oil cooler may be arranged adjacent to the left side of the radiator62and at the top or bottom of the condenser82B. This is because the vertical dimension of the condenser82B is typically somewhat smaller than the radiator62.

The fan90is positioned adjacent to the right side of the radiator62. The fan90is mounted to the bottom portion3B via the radiator62, for example, by being attached to the radiator62via a resin fan shroud. The fan90is arranged, for example, in two rows in the longitudinal direction (the front-rear direction) of the radiator62and in two stages in the height direction (vertical direction). The fan90sucks air from the radiator62side (left side) toward the right side, and blows air to the radiator62, the condenser82B, and the like.

The fan90may be positioned adjacent to the left side of the condenser82B, the radiator62, and the like. In this case, the fan90blows air to the radiator62, the condenser82B, and the like, by pushing out the air from the left side to the side of the condenser82B and the radiator62(right side).

The battery46and the compressor82A are arranged at the left end at the rear portion of the upper turning body3, i.e., to the left of the radiator62, the condenser82B, and the fan90.

The battery46is attached to the bottom portion3B, for example, via a bracket.

The compressor82A is positioned above the battery46, for example, by being mounted on a stand that is standing from the bottom portion3B.

A charging port72is provided on the side surface of the cabin10of the upper turning body3. Charging ports72A and72B are arranged, for example, one behind the other. Also arranged within the cabin10are the DC-DC converter44and the in-vehicle charger70.

For example, as illustrated inFIG.9, a maintenance door3D (an example of a door) is provided at the rear portion of the upper turning body3(the house portion3H).

In this example, as described above, the relatively large power storage device19is arranged on the right front portion of the upper turning body3, and a group of elements having a relatively small size is aggregated at the rear portion of the upper turning body3. Therefore, the worker can easily access this group of elements via the maintenance door3D.

The maintenance door3D includes maintenance doors3D1to3D3.

The maintenance door3D1is provided in the center portion in the left-right direction at the rear portion of the house portion3H and can be opened upwardly with the axis in the left-right direction of the upper surface of the house portion3H as a fulcrum. Thus, the worker can access the pump motor12, the control valve17, the inverter18, the hydraulic oil tank T, and the like, by opening the maintenance door3D1and perform various maintenance operations. In particular, the worker can easily perform maintenance of a hydraulic device such as oil filters of the hydraulic oil tank T, for which maintenance is relatively highly necessary and frequent.

The maintenance door3D2is provided on the side surface on the left end at the rear portion of the house portion3H, and can be opened leftward with the vertical axis of the side surface of the house portion3H as a fulcrum. This allows the worker to access the battery46, the compressor82A, the condenser82B, the radiator62, and the like by opening the maintenance door3D2, and perform various maintenance operations.

The maintenance door3D3is provided on the side surface on the right end of at the rear portion of the house portion3H and can be opened leftward with the vertical axis of the side surface of the house portion3H as a fulcrum. Accordingly, the worker can access the main pump14, the pilot pump15, or nearby elements by opening the maintenance door3D3and perform various maintenance operations. In particular, the worker can easily perform maintenance of the filters positioned near the main pump14, for which the necessity and frequency of maintenance are relatively high.

In this example, the rear portion of the upper turning body3is configured to have a substantially circular arc shape about the center of a turning center (axis center)3X in a top view. Accordingly, the turning radius of the rear portion of the upper turning body3can be relatively small. The turning radius of the rear portion of the upper turning body3means the radius centered around the turning center3X of the trajectory (outer edge) drawn by the rear portion of the upper turning body3when the upper turning body3turns. The excavator100corresponds to, for example, a rear ultra-small turning radius excavator. A rear ultra-small turning radius excavator means an excavator in which the ratio of the turning radius of the rear portion of the upper turning body3is less than or equal to 120 percent with respect to half (½) the full width of the crawler1C. This allows the excavator100to improve workability in a small and narrow worksite.

On the other hand, in the case of the rear ultra-small turning radius excavator, the space of the rear portion of the upper turning body3, particularly the spaces at the left and right end portions, are reduced, and is relatively small. Further, motorization tends to proceed mainly with small machines, and, therefore, even when the excavator100is not a rear ultra-small turning radius excavator, in the electrically operated excavator100, the space at the rear portion of the upper turning body3is limited and tends to be relatively small. Therefore, if a relatively large element is placed at the rear portion of the upper turning body3, dead space may be increased and it may not be possible to achieve an efficient element arrangement structure.

In contrast, in this example, the power storage device19, which is one of the largest elements mounted on the upper turning body3, is arranged at the right front portion of the upper turning body3. The pump motor12and the main pump14are mounted at the rear portion of the upper turning body3.

Therefore, in the excavator100, the pump motor12, the main pump14, and the like having a relatively small size are arranged at the rear portion of the upper turning body3, so that the dead space can be relatively reduced. Then, the excavator100can secure a relatively large arrangement space for the power storage device19along the right side surface of the upper turning body3, where the change in the horizontal position is relatively small across the front-rear direction from the top view. Therefore, the excavator100can achieve an efficient element arrangement structure in the upper turning body3including the power storage device19.

In this example, the excavator100may be a rear ultra-small turning radius excavator in which the ratio of the turning radius of the rear portion of the upper turning body3is less than or equal to 120 percent with respect to half (½) the full width of the lower traveling body1. Specifically, the upper turning body3may have a rear shape that is a substantially circular arc shape based on the turning center3X in the upper view.

Accordingly, the excavator100can achieve a relatively small turning radius at the rear portion of the upper turning body3by an efficient arrangement structure including the power storage device19. Thus, the excavator100can improve the work efficiency in a small and narrow worksite.

Also in this example, the control valve17is arranged on at least one of the main pump14and the pump motor12.

Thus, the excavator100can secure the space above the main pump14or the pump motor12having a relatively small height dimension, as a space for arranging of the control valve17. Further, in the excavator100, the control valve17supplied from the main pump14is positioned relatively close to the main pump14, thereby allowing the piping of the hydraulic oil to be relatively short. Therefore, the excavator100can achieve a more efficient arrangement structure of the elements in the upper turning body3.

Also, in this example, the main pump14may be arranged below the liquid level of the hydraulic oil in the hydraulic oil tank T.

Thus, the excavator100can reduce the occurrence of air entrainment in the main pump14.

Also, in this example, the power storage device19may be arranged in a range from the right front portion of the upper turning body3to the right center portion in the horizontal direction of the upper turning body3. The main pump14may be located behind the power storage device19. The pump motor12may be positioned to the left of the main pump14so that the main pump14can be mechanically driven.

Accordingly, the excavator100can secure a relatively large capacity of the power storage device19while the main pump14having a relatively small size is arranged behind the power storage device19. Therefore, it is possible to reduce the dimension in the front-rear direction in the right corner (right end) at the rear portion of the upper turning body3. Therefore, the excavator100can both secure the capacity of the power storage device19and reduce the turning radius of the rear portion of the upper turning body3.

In this example, the hydraulic oil tank T may be positioned in front of the pump motor12and to the left of the power storage device19.

Thus, the hydraulic oil tank T can be specifically arranged and the capacity thereof can be secured by using the space at the front of the pump motor12and the power storage device19.

Also, in this example, the radiator62may be positioned to the left of the pump motor12.

Thus, the radiator62can be specifically arranged using the space on the left side at the rear portion of the upper turning body3.

In this example, the rear portion of the house portion3H in the upper turning body3may be provided with the maintenance door3D by which the elements mounted in the upper turning body3can be accessed.

This allows the worker to easily access a group of relatively small elements relative to the power storage device19, that are aggregated and arranged at the rear portion of the upper turning body3as described above.

[Details of Power Storage Device]

Next, the details of the power storage device19will be described with reference toFIGS.10to13.

FIGS.10and11are perspective views illustrating an example and another example of a power storage device.FIG.12is an exploded view illustrating an example of a configuration of a power storage module19MD.FIG.13illustrates an example of a coupling structure between the power storage modules.

As illustrated inFIGS.10and11, the power storage device19is configured by a plurality of the power storage modules19MD stacked in the vertical direction, and adjacent power storage modules in the vertical direction are connected to each other by a wire harness19C. In this example, a plurality of the power storage modules19MD are connected in series, and adjacent power storage modules19MD in the vertical direction have a positive terminal of one of the power storage modules19MD connected to a negative terminal of the other power storage modules19MD by one wire harness19C.

Note that in a case where at least some of the plurality of power storage modules19MD are connected in parallel, the power storage modules19MD adjacent in the vertical direction, which are to be connected in parallel, may be connected by two wire harnesses19C connecting the positive terminals of these two modules and connecting the negative terminals of these two modules, respectively.

The power storage device19is mounted to the bottom portion3B (turning frame) of the upper turning body3via a mount member19MT mounted to the power storage module19MD at the lowest layer.

As illustrated inFIG.12, the power storage module19MD includes a plurality (eight in this example) of battery modules BMD, a battery management part19MU, a housing19H, a service plug installing part19SH, and a cover19CV.

The battery module BMD is an assembly configured by a plurality of battery cells connected in series.

The battery management part BMU communicates with various sensors built into the power storage module19MD, acquires the detection data sequentially, communicates with the controller30D of a higher level, and transmits the detection data to the controller30D. Various sensors are voltage sensors, current sensors, temperature sensors, and the like. This allows the controller30D to monitor the state of the battery module BMD and the state of each battery cell included in the battery module BMD.

The housing19H houses elements of the power storage module19MD, such as a plurality of the battery modules BMD and the battery management part BMU. The housing19H is made of a metal such as, for example, an aluminum alloy or iron. The housing19H includes the accommodating part19H1for housing elements and a lid19H2for sealing an opening in the upper portion of the accommodating part19H1. The lid19H2is fastened in a vertical direction by bolts BLT1(seeFIG.13) to a flange FL (seeFIG.13) provided on the outer edge of the opening of the accommodating part19H1.

The plurality of power storage modules19MD each have the housing19H in substantially the same shape. Accordingly, the plurality of power storage modules19MD can be easily stacked in a vertical direction because the shape is substantially the same in a top view.

Note that the housing19H of the plurality of power storage modules19MD is substantially the same in the basic shape manufactured by forging or casting, and there may be some difference in the additional processing. For example, the power storage module19MD at lowest layer among the plurality of power storage modules19MD may be specially machined for coupling to the mount member19MT. The housing19H of some of the plurality of power storage modules19MD may be specially machined to mount a bracket for supporting other elements when mounted on the upper turning body3.

The service plug installing part19SH (an example of a hole) is a hole for installing a service plug to cut off the electrical connection of the plurality of battery modules BMD included in the power storage module19MD. The service plug installing part19SH is provided on the side surface of the housing19H (the accommodating part19H1). Thus, as illustrated inFIGS.10and11, in a state of mounting the plurality of power storage modules19MD stacked in a vertical direction on the upper turning body3, the worker can access the service plugs of each power storage module19MD by simply removing the cover19CV.

The sealing structure of the housing19H is achieved when a service plug is mounted (for example, fitted) to the service plug installing part19SH.

The cover19CV is detachably mounted on the side surface of the housing19H (the accommodating part19H1) so as to cover the service plug installing part19SH, i.e., the service plug. This allows the cover19CV to protect the service plug. The cover19CV has a structure such that the cover19CV cannot be mounted to the housing19H (the accommodating part19H1) when the service plug is not mounted completely to the service plug installing part19SH (for example, in a semi-fitting state). This prevents the case in which the cover19CV is closed when the service plug is not mounted properly due to human error.

The plurality of power storage modules19MD may also be equipped with relevant devices of the power storage device19distributed among the plurality of power storage modules19MD. Relevant devices include, for example, the controller30D and a junction box. A junction box performs relay of power between the power storage device19and a plurality of other devices (e.g., the inverter18, the DC-DC converter44, the in-vehicle charger70, the charging port72B, and the like). For example, the controller30D may be housed within the housing19H of any one of a plurality of the power storage modules19MD, and a junction box may be housed within the housing19H of another one of the power storage modules19MD. This allows for the free space in each of the plurality of power storage modules19MD to be used for housing the relevant devices of the power storage device19.

As illustrated inFIG.13, the housings19H of the power storage modules19MD adjacent in the vertical direction are directly coupled in the vertical direction.

The lower end of the side surface of the accommodating part19H1is provided with a rib RB1which circulates so as to extend along the outer edge in a top view. Ribs RB2are provided at predetermined intervals along the outer edge in a top view, in a range of a height direction between the rib RB1at the lower end and the flange FL at the top end of the side surface of the accommodating part19H1.

A fastening hole FH11is provided at a point where the rib RB2in the flange FL of the accommodating part19H1is connected, and a fastening hole FH12is provided at a corresponding point of the lid19H2in a top view. Accordingly, in a state where the positions of the fastening holes FH11and FH12are aligned, the bolts BLT1is inserted into and fastened to the fastening holes FH11and FH12, such that the lid19H2can be mounted to the accommodating part19H1, and the accommodating part19H1can be sealed by the lid19H2.

A seal member is provided between the back surface of the lid19H2and the flange FL of the accommodating part19H1to ensure sealing.

A recess RC is provided on the lower surface of the rib RB1of the accommodating part19H1. The number of the recesses RC arranged are the same as the number of the bolts BLT1, to house the head of the bolt BLT1when the housing19H (the accommodating part19H1) is stacked on the housing19H (the lid19H2) of the adjacent power storage module19MD below. This allows the head of the bolt BLT1on the upper surface of the housing19H of the lower power storage module19MD to not come into contact with the lower surface of the housing19H (the accommodating part19H1) of the upper power storage module19MD when the power storage modules19MD are stacked in the vertical direction. Accordingly, it is possible to prevent the bolt BLT1from being damaged or prevent the dimension of the power storage device19in the height direction from being increased by the length of the head of the bolt BLT1.

The rib RB1of the accommodating part19H1is provided with a plurality of fastening holes FH21which penetrate from the top surface to the bottom surface of the rib RB1. The plurality of fastening holes FH21are positioned between two adjacent ribs RB2at the outer edge of the accommodating part19H1in a top view.

The flange FL of the accommodating part19H1is provided with a plurality of fastening holes FH22which penetrate from the top surface to the bottom surface of the flange FL. A plurality of fastening holes FH22are provided at substantially the same position as the fastening holes FH21in a top view.

The lid19H2is provided with a plurality of fastening holes FH23that penetrate from the top surface to the bottom surface of the lid19H2. The plurality of fastening holes FH23are provided at substantially the same position as those of the fastening holes FH21and FH22in a top view, when the accommodating part19H1and the lid19H2are coupled to each other.

Therefore, two power storage modules19MD can be coupled by having the bolts BLT2inserted from above and fastening with the fastening holes FH21of the upper power storage module19MD (the housing19H) and the fastening holes FH22and FH23of the lower power storage module19MD (the housing19H).

For example, a stand may be mounted on the bottom portion3B of the upper turning body3and the power storage modules19MD may be attached to the stand so as to be stacked in the vertical direction. However, if, for example, the number of power storage modules19MD is to be changed for each specification of the excavator100, it may be necessary to change the stand, resulting in increased cost. On the other hand, it is possible to set a relatively large stand to match the assumed maximum number of the power storage modules19MD, but if, for example, the number of the power storage modules19MD to be mounted is relatively small, the stand may constrain the layout of other devices. For example, a relatively large stand may increase the cost, or the weight of a relatively large stand may reduce the energy consumption efficiency.

In contrast, in this example, the power storage device19is configured by stacking a plurality of power storage modules19MD in the vertical direction. In the plurality of power storage modules19MD, the housings19H of the adjacent power storage modules19MD in the vertical direction are coupled to each other.

Accordingly, it is possible to mount a plurality of the power storage modules19MD to the upper turning body3via the power storage module19MD of the lowest layer, by merely coupling the housings19H of the power storage modules19MD adjacent in the vertical direction. Therefore, when the number of the power storage modules19MD is changed according to the specification of the excavator100or the like, for example, as in the case ofFIGS.10and11, the number of the power storage modules19MD can be easily changed. Accordingly, the capacity of the power storage device19can be easily changed.

In this example, the plurality of power storage modules19MD may each be configured to have an upper coupling structure (e.g., the fastening holes FH22, FH23) configured to be compatible with the lower coupling structure (e.g., the fastening holes FH21) of all other power storage modules19MD.

Similarly, the plurality of power storage modules19MD may each be configured to have a lower coupling structure (e.g., the fastening holes FH21) configured to be compatible with the upper coupling structure (e.g., the fastening holes FH22, FH23) of all other power storage modules19MD.

Thus, for example, a plurality of the power storage modules19MD can be stacked and coupled in any order, and, therefore, a plurality of the power storage modules19MD can be stacked and mounted to the upper turning body3more easily. Thus, it is easier to change the number of power storage modules19MD.

Further, in this example, the plurality of power storage modules19MD may have substantially the same shape with each other in a top view.

Thus, for example, a plurality of the power storage modules19MD can be stacked in any order, and, therefore, a plurality of the power storage modules19MD can be stacked and mounted to the upper turning body3more easily. Thus, it is easier to change the number of power storage modules19MD.

Also, in this example, at least two or more of the plurality of power storage modules19MD may have the housing19H of substantially the same external shape.

Thus, for example, a plurality of the power storage modules19MD can be stacked in any order, and, therefore, a plurality of the power storage modules19MD can be stacked and mounted to the upper turning body3more easily. Thus, it is easier to change the number of power storage modules19MD.

In this example, the relevant devices of the power storage device19may be distributed among and housed in the housings19H of the plurality of power storage modules19MD.

Thus, it is possible to effectively use the free space of each of the housings19H of a plurality of the power storage modules19MD.

In this example, the relevant device may include at least one of the controller30D for controlling the power storage device19and a junction box for relaying power between the power storage device19and a plurality of other devices.

This specifically allows the controller30D and the junction box to be distributed among and housed in the housings19H of the plurality of power storage modules19MD.

In this example, the plurality of power storage modules19MD may each include the service plug installing part19SH for detachably mounting a service plug that blocks the power path, on the side surface of the housing19H, and the cover19CV covering the service plug installing part19SH.

This allows the worker to remove the cover19CV on the side of the housing19H and access the service plug, for example, during maintenance of the power storage device19, even when a plurality of the power storage modules19MD are stacked in the vertical direction. Therefore, it is possible to easily cut off the power path during maintenance of the power storage device19.

In this example, the housing19H may include the accommodating part19H1for housing the battery module BMD and having the upper portion that can be opened, the lid19H2for closing the upper portion of the open accommodating part19H1, and a plurality of the bolts BLT1for fastening the lid19H2to the accommodating part19H1in the vertical direction. The housings19H of the power storage modules19MD adjacent to each other in the vertical direction may be coupled together by a plurality of the bolts BLT2fastened in the vertical direction. In the housing19H, the fastening holes FH21, FH22, and FH23for fastening the bolts BLT2may be provided between two adjacent fastening holes FH11and FH12in which the bolts BLT1are fastened.

Thus, for example, a coupling structure that couples the housings19H of the power storage modules19MD adjacent to each other in the vertical direction is arranged near the coupling structure of the accommodating part19H1and the lid19H2of the housing19H, and a situation in which the outer edge of the housing19H extends outwardly in a top view can be avoided. Therefore, the coupling structure of the accommodating part19H1and the lid19H2of the housing19H and the coupling structure that couples the housings19H of the power storage modules19MD adjacent to each other in the vertical direction can both be achieved within a smaller space.

In this example, when the housing19H is stacked on the housing19H of another power storage module19MD, the housing19H may have, on the lower surface thereof, the recess RC at substantially the same position as the bolt BLT1of the housing19H of the other power storage module19MD.

This allows the recess RC to house the head of the bolt BLT1when the housing19H of the other power storage module19MD is stacked on top of the housing19H. Therefore, it is possible to avoid a situation in which the head of the bolt BLT1of the lower housing19H contacts the lower surface of the upper housing19H. Accordingly, it is possible to prevent the head of the bolt BLT1from being damaged, to prevent an increase in the vertical dimension of the power storage device19caused by the head of the bolt BLT1, or the like.

[Operation/Stop Switching Method of DC-DC Converter]

Next, a method of switching between the operation and stop of the DC-DC converters44A and44B will be described with reference toFIGS.14and15.

FIG.14is a diagram illustrating a method of switching between the operation and stop of the DC-DC converters44A and44B.FIG.15is a diagram illustrating the conversion efficiency of the DC-DC converter44.

InFIG.14, there is no significance in the intervals of the scales of the current consumption, and these are illustrated merely to simulate the magnitude relationship between the threshold values I1 and I2 and the maximum value Imax.

In this example, the DC-DC converters44A and44B differ from each other in current capacity, i.e., the maximum value of current that can be output. Specifically, the DC-DC converter44A is configured so that the current capacity is relatively small and the DC-DC converter44B is configured so that the current capacity is relatively large.

As illustrated inFIG.14, in this example, the controller30E switches the operation/stop of the DC-DC converters44A and44B in accordance with the current required by all of the low voltage devices, i.e., the current consumption of all of the low voltage devices. The controller30E can acquire the current consumption of all of the low voltage device based on the output of the sensor48.

Specifically, the controller30E causes the DC-DC converter44A to operate and causes the DC-DC converter44B to stop, when the current consumption of all of the low voltage devices is less than or equal to the threshold value I1 (>0). The threshold value I1 is set to be somewhat less than the maximum output current of the DC-DC converter44A. That is, the controller30E supplies power to the battery46or the low voltage device only with the DC-DC converter44A having a relatively low current capacity, in the range where the current consumption of all of the low voltage devices is less than or equal to the threshold value I1.

The controller30E causes the DC-DC converter44A to stop and causes the DC-DC converter44B to operate, when the current consumption of all of the low voltage devices is greater than the threshold value I1 and less than or equal to the threshold value I2 (>11). The threshold value I2 is set to be somewhat less than the maximum output current of the DC-DC converter44B. That is, the controller30E supplies power to the battery46and the low voltage device only with the DC-DC converter44B having a relatively high current capacity, in a range where the current consumption of all of the low voltage devices is greater than the threshold value I1 and less than or equal to the threshold value I2.

Note that a situation may arise in which both of the DC-DC converters44A and44B stop instantaneously when the current consumption of all of the low voltage devices changes from a state of less than or equal to the threshold value I1 to a state greater than the threshold value I1 or vice versa. However, the battery46functions as a buffer, and, therefore, problems such as instantaneous interruption of the power supply to the low voltage device will not arise.

The controller30E causes both the DC-DC converters44A and44B to operate, when the current consumption of all of the low voltage devices is greater than the threshold value I2 and less than or equal to the maximum value Imax. That is, the controller30E supplies power to the battery46and to the low voltage device with both the DC-DC converters44A and44B, in the range where the current consumption of all of the low voltage devices is greater than the threshold value I2.

A hysteresis is provided in the method of switching between the operation and stop of the DC-DC converters44A and44B, in a case in which the current consumption of all of the low voltage devices rises and a case in which this current consumption drops. The threshold value I1 and the threshold value I2 may be set to different values for each of these cases.

As illustrated inFIG.15, the conversion efficiency of the DC-DC converter44A (see graph line1501) is higher than the conversion efficiency of the DC-DC converter44B (graph line1502A) in the range where the output current is less than or equal to the threshold value I1. This is because the smaller the current capacity, the more the conversion efficiency tends to rise in response to an increase of the output current. Therefore, in the range in which the current consumption of all of the low voltage devices is less than or equal to the threshold value I1, by causing only the DC-DC converter44A to operate, the conversion efficiency of the entire DC-DC converter44can be relatively increased.

Further, the conversion efficiency of the DC-DC converter44B remains relatively high in a range in which the output current is greater than the threshold value I1 and less than or equal to than the threshold value I2 (see graph line1502). On the other hand, when the output current exceeds the threshold value I1, the conversion efficiency of the DC-DC converter44A is slightly reduced because the output current is close to the upper limit (see graph line1501A). Therefore, when the current consumption of all of the low voltage devices is greater than the threshold value I1 and less than or equal to the threshold value I2, the conversion efficiency of the entire DC-DC converter44can be relatively increased by causing only the DC-DC converter44B to operate.

Further, if the current consumption of all of the low voltage devices exceeds the threshold value I2 to a certain extent, the DC-DC converter44B alone cannot accommodate the current consumption of all of the low voltage devices. Therefore, if the current consumption of all of the low voltage devices is greater than the threshold value I2, by causing the DC-DC converter44A to operate in addition to the DC-DC converter44B, the current consumption of all of the low voltage devices can be accommodated. In this case, the output current of the DC-DC converter44B is maintained at a relatively high level so that the conversion efficiency of the DC-DC converter44B is maintained at a relatively high level (see graph line1503). Also, the DC-DC converter44A is maintained at a relatively high conversion efficiency (graph line1504), by appropriate control of the output current, excluding the region of relatively low conversion efficiency (graph line1504A). This allows the conversion efficiency of the entire DC-DC converter44to be relatively high.

Thus, in this example, the excavator100uses the plurality of the DC-DC converters44A and44B connected in parallel to supply power to the low voltage device and the battery46.

This allows the respective output currents of the DC-DC converters44A and44B to rise relatively fast. Therefore, the conversion efficiency of the entire DC-DC converter44can be relatively high. Therefore, the power consumption of the power storage device19can be reduced, and the operating time of the excavator100can be relatively long.

In this example, the current capacities of the DC-DC converters44A and44B are set to differ from each other.

Thus, it is possible to switch between operating only the DC-DC converter44A, operating only the DC-DC converter44B, and operating both the DC-DC converters44A and44B, in accordance with the current consumption of all of the low voltage devices. Therefore, the conversion efficiency of the entire DC-DC converter44can be further increased. Accordingly, the power consumption of the power storage device19can be further reduced to further increase the operating time of the excavator100.

In this example, the controller30E switches the operation/stop of the DC-DC converters44A and44B in accordance with the current consumption of all of the low voltage devices.

Accordingly, it is possible to specifically switch between operating only the DC-DC converter44A, operating only the DC-DC converter44B, and operating both the DC-DC converters44A and44B, in accordance with the current consumption of all of the low voltage devices.

[Control Method when Limiting Power Supply from DC-DC Converter]

Referring now toFIGS.16to20, a control method by the control device30at the time of limiting the power supply from the DC-DC converter44to the battery46or to a low voltage device, will be described.

Limiting the power supply from the DC-DC converter44to the battery46or the low voltage device includes, for example, stopping the power supply. Further, limiting the power supply from the DC-DC converter44to the battery46or the low voltage device includes, for example, stopping the power supply from one of the DC-DC converters44A,44B to the battery46or the low voltage device, i.e., limiting the current that can be supplied to the entire DC-DC converter44. Stopping the power supply from the DC-DC converter44to the battery46or the low voltage device includes, for example, stopping the power supply due to an abnormality in the DC-DC converter44. Abnormalities in the DC-DC converter44include, for example, an input overvoltage in which the input voltage from the power storage device19exceeds (surpasses) a predetermined range, or an input undervoltage in which the input voltage from the power storage device19falls below the predetermined range. Abnormalities in the DC-DC converter44include, for example, an output overvoltage in which the output voltage to the battery46or the low voltage devices exceeds (surpasses) a predetermined range, or an output undervoltage in which the output voltage falls below a predetermined range. Abnormalities in the DC-DC converter44also include, for example, short circuits in the circuit of the DC-DC converter44. Abnormalities in the DC-DC converter44may also include, for example, overcurrent. Abnormalities in the DC-DC converter44include, for example, overheating in which the temperature of a predetermined portion of the DC-DC converter exceeds (surpasses) a predetermined range. Abnormalities in the DC-DC converter44include a communication abnormality with an external device such as the controller30E. Abnormalities in the DC-DC converter44include, for example, excessive power supply voltage where the power supply voltage of the DC-DC converter44exceeds (surpasses) a predetermined range or insufficient power supply voltage where the power supply voltage falls below a predetermined range. Also, stopping the power supply from the DC-DC converter44to the battery46or the low voltage device may include, for example, temporary output limits due to the transition to the protective mode of the DC-DC converter44.

<First Example of Control Method>

FIG.16is a flowchart schematically illustrating a first example of a control process during limitation of power supply from the DC-DC converter44.FIG.17is a diagram illustrating an example of the voltage change of the battery46during limitation of power supply from the DC-DC converter44.

The flowchart begins when the power supply from the DC-DC converter44to the battery46or the low voltage device is limited. Specifically, the controller30E may send a signal to the controller30A indicating that the power supply from the DC-DC converter44is limited due to a limited power supply from the DC-DC converter44or due to an abnormality or the like. When the controller30A receives the signal, the process of this flowchart may start. Hereinafter, the same may apply to the flowcharts ofFIGS.18to20, which will be described later.

As illustrated inFIG.16, in step S102, the controller30A reduces the current consumption of the low voltage device by limiting the operation of the low voltage device. This allows the current consumption of the low voltage device to be reduced in a situation where the power supply from the DC-DC converter44to the battery46and the low voltage device is limited, and to allow the controllers30A to30E to operate for a relatively long time by the power of the battery46alone. As a result, the controller30A can relatively increase the operable time of various devices of the excavator100other than low voltage devices subject to operation limitations and relatively increase the operable time of the excavator100.

After the processing of step S102, the controller30A may report to the user through the output device50that the operation of the low voltage device is limited. The controller30A may transmit a report signal through the communication device that the operation of the low voltage device is limited to the external device when the excavator100is remotely operated or remotely monitored.

The operation limitation of the low voltage device includes, for example, stopping the operation of the low voltage device. This allows the current consumption of the target low voltage device to be reduced to substantially zero. The operation limitation of the low voltage device includes a state in which the operation continues in an operation state in which the performance of the low voltage device is relatively low (hereinafter referred to as the “performance limitation state”). This allows the current consumption of the target low voltage device to be reduced compared to the case of the operation state in which the performance of the target low voltage device is relatively high.

The low voltage device for which the current consumption is to be reduced, is the low voltage device with relatively high current consumption. The target low voltage device includes, for example, a water pump64. The performance limitation state of the water pump64includes, for example, a limited state such that the discharge flow rate of the water pump64is relatively low as compared to a regular state. The target low voltage device also includes, for example, a fan90. The performance limitation state of the fan90includes, for example, a limited state such that the revolution speed of the fan90is relatively low as compared to a regular state. The target low voltage device also includes, for example, an air conditioning device80. The performance limitation state of the air conditioning device80includes, for example, an operation state that is limited so that the set temperature of the air conditioning device80is relatively high in a situation where the set temperature of the air conditioning device80is lower than the outside temperature (e.g., in summer). The performance limitation state of the air conditioning device80also includes, for example, an operation state in which the set temperature of the air conditioning device80is relatively low in a situation in which the set temperature of the air conditioning device80is higher than the outside temperature (e.g., in winter).

The refrigerant circuit66is filled with a refrigerant having a relatively large capacity. Therefore, even when the operation of the water pump64or the fan90is limited, the heat of the cooling target is transferred to the refrigerant circuit66. Therefore, although the cooling performance is reduced, the cooling device60can continue cooling the cooling target even when the operation of the water pump64or the fan90is limited.

In step S102, the controller30A may stop the operation of the target low voltage device, or the controller30A may cause the operation state of the target low voltage device to transition to the performance limitation state, or the controller30A may apply either the stop of operation of the target low voltage device or the transition to the performance limitation state depending on the situation.

For example, the controller30A may determine whether the operation of the target low voltage device is to be stopped or whether to transition to the performance limitation state, depending on the voltage of the battery46. The voltage of the battery46can be identified based on the output of the sensor48. Specifically, when the voltage of the battery46is relatively high, the controller30A may set the operation of the target low voltage device to a performance limitation state, and when the voltage of the battery46is relatively low, the operation of the target low voltage device may be stopped.

In step S102, the controller30A may limit the operation of all target low voltage devices, such as the water pump64, the fan90, and the air conditioning device80, or may limit the operation of some of these devices. In step S102, the controller30A may either limit the operation of all target low voltage devices, such as the water pump64, the fan90, and the air conditioning device80, or limit the operation of some target low voltage devices, depending on the situation.

For example, the controller30A may vary the number of target low voltage devices for which the operation is to be limited, depending on the voltage of the battery46. Specifically, the controller30A may increase the number of target low voltage devices for which the operation is to be limited, as the voltage of the battery46decreases. In this case, the controller30A may preferentially limit the operation of the water pump64and the fan90over the air conditioning device80. Further, when the fan90for blowing air to the condenser82B and the fan90for blowing air to the radiator62are separately provided, the controller30A may prioritize operation limitations on the latter fan90over the former fan90.

Hereinafter, various modes of operation limitation of the target low voltage device described above may be suitably applied, also in the case ofFIGS.18to20, which will be described later.

When the process of step S102is completed, the controller30A proceeds to step S104.

In step S104, the controller30A determines whether the DC-DC converter44has returned to the regular operation state from the operation limitation state. If the DC-DC converter44has returned to the regular operation state, the controller30A proceeds to step S106, and if not, the controller30A repeats the process of this step until the DC-DC converter returns to the regular operation state.

In step S106, the controller30A cancels the operation limitation of the target low voltage device.

The controller30A may report to the user through the output device50, that the operation limitation of the target low voltage device is canceled, concurrently with the canceling of the operation limitation of the target low voltage device. The controller30A may transmit a report signal to the external device to cancel the operation limitation of the target low voltage device through the communication device when remote operation or remote monitoring of the excavator100is performed. Hereinafter, the same may be applied to step S204of the second example (FIG.18), step S302of the third example (FIG.19), and step S402of the fourth example (FIG.20) described later.

When the processing in step S106is completed, the controller30A completes the processing of the flowchart.

In the case where the operation limitation of the DC-DC converter44is very unlikely to be canceled, such as in the case of an operation limitation due to an abnormality in the DC-DC converter44, the processing of the steps S104and S106may be omitted.

For example, as illustrated inFIG.17, when the power supply from the DC-DC converter44to the battery46is limited, and the low voltage device is operated by the using the power from the battery46, the voltage of the battery46drops. In particular, in the electrically operated excavator100, the power consumption of the controllers30B and30D of the electric driving system and the power supply system, and the power consumption of the cooling system such as the water pump64and the fan90, are relatively increased in comparison with a regular hydraulic excavator, and the voltage drop caused by the internal resistance is significant. Therefore, if the operation limitation of the DC-DC converter44is not canceled, and the operation limitation of the low voltage device is not applied, the voltage of the battery46drops sharply. Then, the voltage immediately reaches the lower limit value of the control power supply of the various controllers including the controllers30A to30E included in the control device30, and the various controllers stop (see the dashed line in the figure). As a result, the excavator100is forced to stop. Thus, if the power supply from the DC-DC converter44to the battery46or the low voltage device is limited, in some instances, it may not be possible to cause the excavator100to evacuate to a safe location or it may not be possible to move the excavator100for repair.

In contrast, in this example, the controller30A limits the operation of the low voltage device. Thus, the voltage drop caused by the internal resistance decreases due to the decrease in the current consumption of the low voltage device, and the voltage recovers and the current consumption decreases, so that the voltage drop of the battery46becomes moderate (see solid line in the figure). As a result, the voltage of the battery46reaches the lower limit of the control power supply of the various controllers, ensuring a relatively long period of time until the excavator100is forced to stop. Accordingly, the user may operate the excavator100to cause the excavator100to evacuate to a safe location or to move the excavator100for repair. Also, if the excavator100operates by a fully automatic operation function, the excavator100may automatically evacuate to a safe location, for example, in a predetermined evacuation mode, or automatically move for repair.

As described above, in this example, when the power supply from the DC-DC converter44to the battery46is limited, the controller30A limits the operation of the target low voltage load and reduces power consumption.

This allows the controller30A to reduce the voltage drop of the battery46in the event of the limitation on the power supply from the DC-DC converter44and to ensure a relatively long time until the various controllers are stopped. Therefore, the excavator100(own machine) may be evacuated to a safe location or the excavator100(own machine) may be moved for repair, by operation by an operator or by an automatic operation function.

In this example, the case where power supply from the DC-DC converter44to the battery46is limited, may include a case in which the DC-DC converter44has an abnormality. Specifically, an abnormality in the DC-DC converter44may include at least one of an input overvoltage, an input undervoltage, an output overvoltage, an output undervoltage, a short circuit, an overcurrent, overheat, an excess power supply voltage, an insufficient power supply voltage, and a communication abnormality.

Thus, the controller30A can reduce the voltage drop of the battery46in the event of an abnormality of the DC-DC converter44and ensure a relatively long time until the various controllers are stopped.

In this example, the case where power supply from the DC-DC converter44to the battery46is limited, may include a case in which the power supply from at least one of the plurality of the DC-DC converters44A and44B to the battery46is stopped.

Thus, for example, when the power supply from one of the DC-DC converters44A and44B is stopped, the controller30A can reduce the voltage drop of the battery46and ensure a relatively long time until the various controllers are stopped.

Also, in this example, the low voltage load subject to the operation limitation may include at least one of the water pump64and the fan90.

Accordingly, the controller30A limits the operation of the water pump64and the fan90, which have relatively high current consumption, and specifically, the current consumption of the low voltage device can be reduced.

Also, in this example, the low voltage load subject to operation limitation may include the air conditioning device80.

Accordingly, the controller30A limits the operation of the air conditioning device80having a relatively high current consumption, and can specifically reduce the current consumption of all of the low voltage devices.

Also, in this example, controller30A may preferentially limit the operation of the water pump64and fan90over the operation of the air conditioning device80.

This allows the controller30A to reduce the current consumption of all of the low voltage devices, for example, while taking into account the comfort and health aspects of the user (operator) in the cabin10.

<Second Example of Control Method>

FIG.18is a flowchart schematically illustrating a second example of a control process when the power supply from the DC-DC converter44is limited.

As illustrated inFIG.18, in step S202, the controller30A outputs a control instruction to the controller30B to limit the output of the pump motor12. Specifically, the controller30A may limit the output of the pump motor12by controlling a regulator (not illustrated) to reduce the capacity and load of the variable capacity main pump14. The controller30A may limit the output of the pump motor12by reducing the revolution speed of the pump motor12. The controller30A may implement both of these limitations to limit the output of the pump motor12. Accordingly, the heat generation of the device of the electric driving system and the power supply system can be reduced, and the load of the cooling device60can be reduced.

When the process of step S202is completed, the controller30A proceeds to step S204.

In step S204, the controller30A reduces the current consumption of the low voltage device by limiting the operation of the low voltage device including the water pump64(W/P) and the fan90. Thus, the controller30A can provide a relatively long time for the controllers30A to30E to operate by the power of the battery46alone, as in the first example above.

The processing of steps S206and S208is the same as that of steps S104and S106inFIG.16, and, therefore, the description thereof will be omitted.

When the processing in step S208is completed, the controller30A completes the process of this flowchart.

Thus, in this example, the controller30A limits the output of the pump motor12when limiting the operation of at least one of the water pump64or the fan90.

Accordingly, the controller30A can reduce heat generation from the electric driving system or the power supply system by limiting the output of the pump motor12. Therefore, even when the operation of the water pump64or the fan90is limited, the controller30A can reduce the increase in temperature (overheating) of the device to be cooled by the cooling device60.

The controller30A may identify the temperature state of the device to be cooled based on the output of the temperature sensor54, and limit the output of the pump motor12in accordance with the temperature state of the device to be cooled by the cooling device60. Specifically, the controller30A may limit the output of the pump motor12when the temperature of the device to be cooled by the cooling device60exceeds a predetermined threshold value.

<Third Example of Control Method>

FIG.19is a flowchart schematically illustrating a third example of a control process when the power supply from the DC-DC converter44is limited.

As illustrated inFIG.19, in step S302, the controller30A limits the operation of at least one of the water pump64or the fan90. Therefore, it is possible to reduce the current consumption of all of the low voltage devices.

When the process of step S302is completed, the controller30A proceeds to step S304.

In step S304, the controller30A determines whether the DC-DC converter44has returned to the regular operation state from the operation limitation state. The controller30A proceeds to step S306if the DC-DC converter44has not returned to the regular operation state, and proceeds to step S316if the DC-DC converter44has returned to the regular operation state.

Meanwhile, in step S306, the controller30A determines whether the temperature of the device to be cooled down by the cooling device60exceeds the threshold value T11th (>0) based on the output of the temperature sensor54. If the temperature of the device to be cooled exceeds the threshold value T11th, the controller30A proceeds to step S308, and otherwise returns to step S304.

In step S308, the controller30A temporarily cancels the operation limitation of the water pump64or the fan90for which the operation is limited in step S302. Therefore, it is possible to improve the cooling performance of the cooling device60and prevent the temperature rise of the device to be cooled down.

When the process of step S308is completed, the controller30A proceeds to step S310.

In step S310, the controller30A determines whether the DC-DC converter44has returned to the regular operation state from the operation limitation state. The controller30A proceeds to step S316if the DC-DC converter44has returned to the regular operation state, and proceeds to step S312if the DC-DC converter44has not returned to the regular operation state.

In step S312, the controller30A determines whether the temperature of the device to be cooled down by the cooling device60is less than or equal to the threshold value T12th (<T11th). If the temperature of the device to be cooled is less than or equal to the threshold value T12th, the controller30A proceeds to step S314, and otherwise returns to step S310.

In step S314, controller30A resumes the operation limitation of the water pump64and the fan90, that was temporarily canceled in step S308.

When the process of step S314is completed, the controller30A returns to step S304.

On the other hand, in step S316, the controller30A cancels the operation limitation of the target low voltage device.

When the process of step S316is completed, the controller30A completes the process of the present flowchart.

Thus, in this example, when the temperature of the device to be cooled by the cooling device60is relatively high while the operation of the water pump64or the fan90is limited, the controller30A temporarily cancels the operation limitation of the water pump64or the fan90.

Accordingly, the controller30A can prevent the temperature rise of the device to be cooled while reducing the current consumption of all of the low voltage devices.

<Fourth Example of Control Method>

FIG.20is a flowchart schematically illustrating a fourth example of a control process when the power supply from the DC-DC converter44is limited.

In this example, a control process in a state in which the set temperature of the air conditioning device80is lower than the outside temperature (for example, in summer) is represented.

As illustrated inFIG.20, in step S402, the controller30A limits the operation of the air conditioning device80. Therefore, it is possible to reduce the current consumption of all of the low voltage devices.

When the process of step S402is completed, the controller30A proceeds to step S404.

In step S404, the controller30A determines whether the DC-DC converter44has returned to the regular operation state from the operation limitation state. The controller30A proceeds to step S406if the DC-DC converter44has not returned to the regular operation state, and proceeds to step S416if the DC-DC converter has returned to the regular operation state.

On the other hand, in step S406, the controller30A determines whether the indoor temperature of the cabin10exceeds the threshold value T21th (>0) based on the output of the temperature sensor56. If the temperature of the device to be cooled exceeds the threshold value T21th, the controller30A proceeds to step S408, and otherwise returns to step S404.

In the case of the control process in a situation where the set temperature of the air conditioning device80is higher than the outdoor temperature, it may be determined whether the indoor temperature of the cabin10is lower than a predetermined threshold value.

In step S408, the controller30A temporarily cancels the operation limitation of the air conditioning device80whose operation is limited in step S402. This improves the performance of the air conditioning device80and prevents the increase in the room temperature of the cabin10.

When the process of step S408is completed, the controller30A proceeds to step S410.

In step S410, the controller30A determines whether the DC-DC converter44has returned to the regular operation state from the operation limitation state. The controller30A proceeds to step S416if the DC-DC converter44has returned to the regular operation state, and proceeds to step S412if the DC-DC converter has not returned to the regular operation state.

In step S412, the controller30A determines whether the indoor temperature of the cabin10is less than or equal to the threshold value T22th (<T11th). If the temperature of the device to be cooled is less than or equal to the threshold value T22th, the controller30A proceeds to step S414, and otherwise returns to step S410.

In the case of the control process in a situation where the set temperature of the air conditioning device80is higher than the outdoor temperature, it may be determined whether the indoor temperature of the cabin10is higher than or equal to the predetermined threshold value.

In step S414, the controller30A resumes the operation limitation of the air conditioning device80that was temporarily canceled in step S408.

When the processing of step S414is completed, the controller30A returns to step S404.

Meanwhile, in step S416, the controller30A cancels the operation limitation of the target low voltage device.

When the processing in step S416is completed, the controller30A ends the process of the flowchart.

As described above, in this example, the controller30A temporarily cancels the operation limitation of the air conditioning device80when the indoor temperature of the cabin10exceeds a threshold value in a manner as to deviate from the set temperature of the air conditioning device80, while the operation of the air conditioning device80is limited.

Thus, the controller30A can reduce the current consumption of all of the low voltage devices while preventing a situation in which the indoor temperature of the cabin10is too high in summer or too low in winter.

[Control Process for Start and Stop of Operation Mode]

Referring now toFIGS.21and22, a control process regarding the start and stop of the operation mode of the excavator100will be described.

FIG.21is a flowchart schematically illustrating a control process for starting and stopping the operation mode of the excavator100.FIG.22is a flowchart schematically illustrating an example of an emergency stop process of the excavator100.

The process of the flowchart ofFIG.21is started when a key switch is turned on in response to a predetermined input from a user through the input device52. A key switch is provided in the power system between the battery46and various controllers such as the controllers30A to30E.

As illustrated inFIG.21, in step S502, the controller30A performs a process of starting the operation mode corresponding to an initial process at the time of activation of the excavator100. The operation mode is the default control mode when the excavator100is operating (being driven) to perform regular work, by operating the actuator in response to an operation instruction corresponding to an operator's operation or an automatic operation function.

When the process of step S502is completed, the controller30A proceeds to step S504.

In step S504, the controller30A transitions to an operation mode of corresponding to regular operation of the excavator100.

When the process of step S504is completed, the controller30A proceeds to step S506.

In step S506, the controller30A determines whether the key switch has been turned on. The controller30A proceeds to step S508when the key switch is turned on and proceeds to step S510when the key switch is not turned on.

In step S508, the controller30A performs a process of ending the operation mode corresponding to the ending process when the excavator100stops.

When the processing in step S508is completed, the controller30A ends the process of the flowchart.

On the other hand, in step S510, the controller30A determines whether a charging cable extending from an external power source is connected to the charging port72. For example, when the charging cable is connected to the charging port72A, the in-vehicle charger70sends a signal to the controller30D indicating that the charging cable is connected to the charging port72A. Accordingly, the controller30A can identify that a charging cable is connected to the charging port72A by identifying the reception of a signal from the in-vehicle charger70through the controller30D. For example, when the charging cable is connected to the charging port72B, the controller30D identifies the state in which the charging cable is connected to the charging port72B by communication with a charging station side through contact detection or power line communication. Thus, the controller30A can identify that the charging cable is connected to the charging port72B through the controller30D. The controller30A proceeds to step S512when the charging cable extending from the external power source is connected to the charging port72, and proceeds to step S506when the charging cable is not connected.

In step S512, an emergency stop process of the excavator100is performed. Specifically, the process transitions to the flowchart illustrated inFIG.22.

FIG.22is a flowchart of an emergency stop process when a charging cable is connected to the charging port72A.

As illustrated inFIG.22, in step S602, the controller30A reports to the user, via the output device50, about the emergency stop of the excavator100together with the reason. The controller30A may also report that it is necessary to turn off the key switch once (see step S620) in order to recover from the emergency stop state of the excavator100. The controller30A may transmit a signal to an external device representing an emergency stop or the like of the excavator100through a communication device when the excavator100is remotely operated or remotely monitored.

When the process of step S602is completed and a certain time elapses, the controller30A proceeds to step S604.

In step S604, the controller30A stops the hydraulic driving system. For example, the controller30A blocks the pilot line25through the switching valve25V2by energizing the relay25R to open the relay25R. As a result, the pilot pressure supply to the hydraulic control valve31is cut off (stopped) and the hydraulic actuator does not operate even if the operation device26is operated, and the hydraulic driving system is stopped.

When the process of step S604is completed, the controller30A proceeds to step S606.

In step S606, the controller30A stops the pump motor12through the controller30B.

When it is confirmed through the controller30B that the pump motor12is stopped, the controller30A proceeds to step S608. For example, the controller30A receives a signal relating to the revolution speed of the pump motor output from the inverter18through the controller30B and identifies that the rotation of the pump motor12has been stopped.

In step S608, the controller30A stops the inverter18through the controller30B.

When it is confirmed that the inverter18has stopped, the controller30A proceeds to step S610. For example, the controller30A receives, through controller30B, a signal representing the stop of operation, output from the inverter18, and identifies that the inverter18has been stopped.

In step S610, the water pump64, the fan90, and the air conditioning device80are stopped.

When the process of step S610is completed, the controller30A proceeds to step S612.

In step S612, the controller30A stops the DC-DC converter44through the controller30E.

When it is confirmed that the DC-DC converter44has stopped, the controller30A proceeds to step S614. The controller30A receives, through the controller30E, a signal representing the stop of operation, output from the DC-DC converter44, and identifies that the DC-DC converter44has stopped.

In step S614, the controller30A outputs, through the controller30D, a charge prohibition instruction to the in-vehicle charger70, to prohibit the charging of the power storage device19.

When the charging cable is connected to the charging port72B, in this step, the controller30A may output a signal requesting to prohibit (stop) the external power supply (charging stand) side from charging the power storage device19.

The controller30A proceeds to step S616when it is confirmed that the charge prohibition is applied to the in-vehicle charger70. For example, the controller30A receives a signal representing a charge prohibition state output from the in-vehicle charger70, through the controller30D, and identifies the charge prohibition state of the in-vehicle charger70.

In step S616, controller30A blocks the system main relay through controller30D to separate the power storage device19from the power supply system.

The controller30A proceeds to step S618when it is confirmed that the power storage device19has been separated from the power supply system. For example, the controller30A identifies that the power storage device19is separated from the power supply system by receiving a signal indicating the measurement result of the voltage of the power storage device19input from the power storage device19through the controller30D.

In step S618, controller30A stops all control processing of the control device30.

When the processing of step S618is completed, the controller30A proceeds to step S620.

In step S620, the controller30A determines whether the key switch has been turned off. If the key switch is not turned off, the processing of this step is repeated until the key switch is turned off. If the key switch is turned off, the process of this flowchart is completed.

In the emergency stop process, only one of the stopping of the hydraulic driving system or the stopping of the electric driving system and the power storage system, may be performed. If only the hydraulic driving system is stopped, the processing of step S604through step S618may be omitted. When only the electric driving system and the power storage system are stopped, the processing of step S602is omitted.

Returning toFIG.21, the controller30A proceeds to step S508when the processing of step S512is ended, that is, when the process of the flowchart ofFIG.22, is ended.

Thus, in this example, the controller30A causes the state of the hydraulic actuator to transition to an inoperable state, when the charging cable is connected to the charging port72while the excavator100is operating.

This allows the controller30A to substantially prohibit the continuation of work by the excavator100, in a state where the charging cable is connected to the charging port. Thus, for example, when the excavator100is operating, and a third party connects a charging cable to the charging port72without the user (operator) in the cabin10being aware of this, it is possible to avoid a situation in which the excavator100continues work. Thus, for example, it is possible avoid a situation where the excavator100continues to work and the charging cable breaks or the charging cable is dragged to affect the surroundings of the excavator100, thereby improving the safety of the electrically operated excavator100.

In this example, the controller30A may stop the pump motor12if the charging cable is connected to the charging port72while the excavator100is operating.

This allows the excavator100to stop the main pump14and specifically cause the operation state of the hydraulic actuator to transition to an inoperable state.

When a predetermined cable is connected to the charging port72during operation of the excavator100, the controller30A may cut off the supply of hydraulic oil from the pilot pump15(or the main pump14when the pilot pump15is omitted) to the hydraulic control valve31.

Accordingly, the excavator100can stop supplying pilot pressure from the pilot pump15or the main pump14to the hydraulic control valve31, and specifically cause the operation state of the hydraulic actuator to transition to an inoperable state.

The output device50may report to the user, under the control of controller30A, why the hydraulic actuator transitions to an inoperable state.

This allows the excavator100to cause the user to recognize that the hydraulic actuator transitions to an inoperable state because the charging cable is connected.

[Control Process for Start and Stop of Charging Mode]

Referring now toFIGS.23and24, a control process regarding the start and stop of the charging mode will be described.

FIG.23is a flowchart schematically illustrating an example of a control process for starting and stopping the charging mode of the excavator100.FIG.24is a flowchart schematically illustrating an example of a forced ending process of the charging mode.

FIGS.23and24are flowcharts of an emergency stop process when the charging cable is connected to the charging port72A.

The process of the flowchart ofFIG.23is started, for example, when the charging cable is connected to the charging port72while the excavator100is stopped, i.e., the key switch is off. The process of the flowchart ofFIG.23may be started, for example, when the charging cable is connected to the charging port72with the key switch off and the accessory switch off. The accessory switch is provided in the power path between a predetermined low voltage device, other than the control device30, and the battery46, and is turned on to enable power to be supplied from the battery46and the DC-DC converter44to the low voltage device while the excavator100is stopped.

As illustrated inFIG.23, in step S702, the controller30A starts the start process of the charging mode of the excavator100. The charging mode of the excavator100is a control mode for charging the power storage device19through the charging cable.

When the process of step S702is completed, the controller30A proceeds to step S704.

In step S704, the controller30A determines whether the charging mode start process has been completed. If the charging mode startup process is not completed, the controller30A proceeds to step S706, and if the charging mode startup process is completed, the controller30A proceeds to step S708.

In step S706, the controller30A determines whether a condition (hereinafter, a “start cancel condition”) for cancelling the start of the charging mode is satisfied. The start cancel condition includes, for example, receiving a signal representing an abnormality from the in-vehicle charger70via controller30D. If the start cancel condition is not satisfied, the controller30A returns to step S704. If the start stop condition is satisfied, the controller30A proceeds to step S732.

When the charging cable is connected to the charging port72B, the start cancel condition of this step may include, for example, receiving a signal representing an abnormality from the external power supply (charging stand) side through the controller30D.

Meanwhile, in step S708, the controller30A transitions to the charging mode.

When the process of step S708is completed, the controller30A proceeds to step S710.

In step S710, the controller30A determines whether there is an abnormality in the in-vehicle charger70. Specifically, the controller30A may determine whether a signal representing an abnormality output from the in-vehicle charger70has been received through the controller30D. The controller30A proceeds to step S712when there is no abnormality in the in-vehicle charger70, and proceeds to step S732when there is an abnormality in the in-vehicle charger70.

When the charging cable is connected to the charging port72B, in this step, the controller30A may determine whether a signal representing an abnormality is received from the external power supply (charging stand) side through the controller30D.

In step S712, the controller30A determines whether the key switch is in the OFF state. The controller30A proceeds to step S714when the key switch is in the off state and proceeds to step S732when the key switch is in the on state.

In step S714, controller30A prepares to start charging. Specifically, the controller30A may cause the system main relay to transition to the connection state via the controller30D. The controller30A may report to the user that charging is started through the output device50.

When the process of step S714is completed, the controller30A proceeds to step S716.

In step S716, the controller30A determines whether the charging start condition is satisfied. The charging start condition includes, for example, the key switch being in the off state. The charging start condition includes, for example, that the in-vehicle charger70is in a standby state. For example, the controller30A identifies the state of the in-vehicle charger70by receiving a signal representing the current state from the in-vehicle charger70through the controller30D. The charging start condition includes charging from the DC-DC converter44to the battery46is complete and the battery46is fully charged. For example, controller30A can identify the voltage state of the battery46by receiving the output of the sensor48through the controller30E. The charging start condition includes that the system main relay of the power storage device19is connected. For example, the controller30A can identify the connection state of the system main relay by receiving, through the controller30D, a signal representing the measurement result of the voltage of the power storage device19including the system main relay in the path. If the charging start condition is satisfied, the controller30A proceeds to step S718, and if not, the controller30A proceeds to step S732.

When the charging cable is connected to the charging port72B, the charging start condition may include the condition relating to the state of the external power supply (charging stand side) instead of the condition relating to the state of the in-vehicle charger70.

In step S718, the controller30A starts charging the power storage device19. Specifically, the controller30A outputs an instruction to start charging to the in-vehicle charger70through the controller30D. The controller30A operates the water pump64and the fan90. Accordingly, it is possible to prevent the temperature increase caused by the heat generation of the power storage device19and the in-vehicle charger70.

The controller30A may switch between operation/stop of the water pump64or the fan90while identifying the temperature state of the device to be cooled (such as the power storage device19or the in-vehicle charger70) based on the output of the temperature sensor54while the power storage device19is being charged.

When the process of step S718is completed, the controller30A proceeds to step S720.

In step S720, the controller30A determines whether the charging cancel condition is satisfied. For example, the charging cancel condition includes that the key switch is on. Also, for example, the charging cancel condition may include receiving a signal representing an abnormality of other controllers (such as the controllers30B to30E). If the charging cancel condition is not satisfied, the controller30A proceeds to step S722, and if the charging stop condition is satisfied, the controller30A proceeds to step S732.

In step S722, the controller30A determines whether the charging end condition is satisfied. For example, the charging end condition includes that the state of charge (SOC) of the power storage device19has reached a predefined target value (target charge amount). The target charge amount may be, for example, 100 percent, representing full charge, or may be a lower charge amount (e.g., 80 percent) than full charge that is suitably set manually or automatically. For example, the controller30A receives a signal representing a calculation result of the charging state based on the result of measuring the voltage of the power storage device19from the controller30D, thereby identifying the charging state of the power storage device19. The charging end condition may include, for example, that the charging cable has been removed from the charging port72. If the charging end condition is satisfied, the controller30A proceeds to step S724, and if the charging end condition is not satisfied, the controller returns to step S720.

In step S724, the controller30A stops the water pump64, the fan90, and the air conditioning device80.

When the process of step S724is completed, the controller30A proceeds to step S726.

In step S726, the controller30A prepares for ending the charging of the power storage device19. Specifically, the controller30A may output a control instruction to transition to a standby state, to the in-vehicle charger70. The controller30A may output a control instruction to stop the operation, to the DC-DC converter44.

The controller30A proceeds to step S728upon confirming that the in-vehicle charger70has transitioned to the standby state and the DC-DC converter44has stopped the operation.

In step S728, controller30A blocks the system main relay through the controller30D and separates the power storage device19from the power supply system.

When the controller30A confirms that the power storage device19has been separated from the power supply system, the controller30A proceeds to step S730.

In step S730, the controller30A stops the controller30D of the power storage device19.

When the process of step S730is completed, the controller30A proceeds to step S734.

On the other hand, in step S732, the controller30A performs the forced ending process of the charging mode. Specifically, the process transitions to the flowchart illustrated inFIG.24.

As illustrated inFIG.24, in step S802, the controller30A reports to the user that the charging mode of the excavator100is forcibly ended together with the reason, through the output device50. The controller30A may also report that it is necessary to turn off the key switch once (see step S812) in order to recover from the forced ending of the charging mode. The controller30A may transmit a signal to an external device representing an emergency stop of the excavator100or the like through a communication device when the excavator100is remotely operated or remotely monitored.

When the process of step S802is completed and a certain amount of time elapses, the controller30A proceeds to step S804.

In step S804, the water pump64, the fan90, and the air conditioning device80are stopped.

When the process of step S804is completed, the controller30A proceeds to step S806.

In step S806, the controller30A outputs a charge prohibition instruction to prohibit the charging of the power storage device19and the battery46, to the in-vehicle charger70and the DC-DC converter44, through the controllers30D and30E.

When the charging cable is connected to the charging port72B, in this step, the controller30A may output a signal requesting to prohibit (stop) the external power supply (charging stand) side from charging the power storage device19.

The controller30A proceeds to step S808when it is confirmed that the charging prohibition is applied to the in-vehicle charger70.

In step S808, the controller30A cuts off the system main relay through the controller30D and separates the power storage device19from the power supply system.

When the controller30A confirms that the power storage device19has been separated from the power supply system, the controller30A proceeds to step S810.

In step S810, the controller30A stops the controller30D of the power storage device19.

When the process of step S810is completed, the controller30A proceeds to step S812.

In step S812, controller30A determines whether the key switch has been turned off. If the key switch is not turned off, the processing of this step is repeated until the key switch is turned off. If the key switch is turned off, the process of this flowchart is completed.

Returning toFIG.23, the controller30A proceeds to step S734when the process of step S732, that is, the flowchart ofFIG.24, is completed.

In step S734, the controller30A performs the charging mode end process.

When the processing in step S734is completed, the controller30A completes the process of the flowchart.

Thus, in this example, when the charging cable is connected to the charging port72, the controller30A does not activate the pump motor12even if an input (e.g., an input to turn the key switch on) for activating the pump motor12is received from the user.

This can improve the safety of the electrically operated excavator100, for example, by avoiding the situation where the excavator100starts work during charging and the charging cable breaks or the charging cable is dragged affecting the surroundings of the excavator100.

In this example, the controller30A may start the charging of the power storage device19if the charging cable is reconnected to the charging port72after the input for activating the pump motor12is canceled and the connection of the charging cable to the charging port72is canceled.

Thus, the controller30A can reconfirm the user's intention to charge the power storage device19, for example, when the user has inadvertently turned the key switch on, and then the key switch is turned off again and the charging cable is caused to be reconnected to the charging port72. Thus, controller30A can safely resume the charging of the power storage device19.

The output device50may report to the user about the reason why the pump motor12is not activated in response to an input from the user for activating the pump motor12(e.g., an input for turning the key switch on).

This allows the excavator100to make the user aware that the pump motor12is not activated because the charging cable is connected to the charging port72.

In this example, the controller30A may start the charging of the power storage device19when the charging cable is connected to the charging port72while the accessory switch is on.

This allows the controller30A to activate the low voltage device (e.g., the air conditioning device80, a radio, and the like, described below) of the excavator100at the start of charging of the power storage device19.

[Control Process for Use of Air Conditioning Device During Charging of the Power Storage Device]

Referring now toFIGS.25and26, a control process regarding the use of an air conditioning device during the charging of the power storage device19will be described.

<First Example of Control Process>

FIG.25is a flowchart schematically illustrating a first example of a control process for the use of the air conditioning device80during the charging of the power storage device19.

The process of this flowchart is implemented when the power storage device19is being charged and the accessory switch is on. The accessory switch may be turned on from a state before the power storage device19is charged, or the accessory switch may be turned on after the power storage device19starts to be charged. Hereinafter, the same shall apply to the flowchart ofFIG.26which will be described later.

As illustrated inFIG.25, in step S902, the controller30A turns on the power of the air conditioning device80. This allows the air conditioning device80to operate in response to input from a user (operator) of the cabin10.

When the process of step S902is completed, the controller30A proceeds to step S904.

In step S904, controller30A determines whether the accessory switch has been turned off. The controller30A proceeds to step S906if the accessory switch is not turned off, and proceeds to step S908if the accessory switch is turned off.

In step S906, the controller30A determines whether the charging of the power storage device19has been completed. When the charging of the power storage device19is completed, the controller30A ends the process of this flowchart, and when the charging of the power storage device19is not completed, the controller30A proceeds to step S904.

On the other hand, in step S908, the controller30A turns off the power of the air conditioning device80.

When the process of step S908is completed, the controller30A ends the process of this flowchart.

Thus, in this example, the controller30A operates the air conditioning device80in response to an input from a user when the charging cable is connected to the charging port. Specifically, the controller30A may cause the air conditioning device to operate in response to an input from the user when the accessory switch is on and a predetermined cable is connected to the charging port.

This can improve the comfort and convenience of the user who is present in the cabin10during the charging of the power storage device19.

<Second Example of Control Process>

FIG.26is a flowchart schematically illustrating a second example of a control process relating to the use of the air conditioning device80during the charging of the power storage device19.

As illustrated inFIG.26, the processing of steps S1002, S1004, and S1006is the same as that of steps S902, S904, and S906inFIG.25, and, therefore, the description thereof will be omitted.

In step S1004, the controller30A proceeds to step S1006when the accessory switch is not off and proceeds to step S1020when the accessory switch is off.

In step S1006, when the charging of the power storage device19is not completed, the controller30A proceeds to step S1008, and when the charging of the power storage device19has been completed, the process of this flowchart is ended.

In step S1008, the controller30A determines whether the charge amount (SOC) of the power storage device19is decreasing. For example, the controller30A sequentially receives the charge amount (SOC) calculated from the measurement result of measuring the voltage of the power storage device19through the controller30D to identify the change in the charge amount of the power storage device19. If the charge amount of the power storage device19is decreasing, the controller30A proceeds to step S1010. If the charging amount is not decreasing, the controller30A returns to step S1004.

In step S1010, the controller30A limits the operation of the air conditioning device80. This reduces the power supplied to the air conditioning device80from the power storage device19through the DC-DC converter44.

When the process of step S1010is completed, the controller30A proceeds to step S1012.

In step S1012, the controller30A determines whether the accessory switch is in the off state. If the accessory switch is not in the off state, the controller30A proceeds to step S1014, and if the accessory switch is in the off state, the controller30A proceeds to step S1020.

In step S1014, the controller30A determines whether the charging of the power storage device19has been completed. If the charging of the power storage device19has not been completed, the controller30A proceeds to step S1016. If the charging has been completed, the controller30A ends the process of the flowchart.

In step S1016, the controller30A determines whether the charge amount (SOC) of the power storage device19is increasing at a rate exceeding a predetermined reference rate. The controller30A proceeds to step S1018if the charge amount of the power storage device19is increasing at a rate exceeding a predetermined reference rate, and otherwise returns to step S1012.

In step S1018, the controller30A cancels the operation limitation of the air conditioning device80.

When the process of step S1018is completed, the controller30A returns to step S1004.

On the other hand, step S1020is the same as the processing of step S908inFIG.25, and, therefore, the description thereof will be omitted.

Thus, in this example, the controller30A limits the operation of the air conditioning device80, when the charge amount of the power storage device19decreases in a state where the air conditioning device80is operating while the power storage device19is being charged.

Accordingly, the controller30A can change the charge amount of the power storage device19from a decreasing state to an increasing state, by to the limitation of operation of the air conditioning device80, in a state where the current consumption of the air conditioning device80is relatively high and the charge amount of the power storage device19is decreasing even though the power storage device19is being charged. Accordingly, the controller30A can more appropriately achieve both the charging of the power storage device19and the use of the air conditioning device80while the power storage device19is being charged.

According to an aspect of the present invention, a power storage device can be efficiently arranged in an upper turning body of an electrically operated excavator.

While the embodiments have been described in detail above, the disclosure is not limited to such particular embodiments, and various modifications and variations are possible within the scope of the scope of the appended claims.