Shovel

Abstract

To provide a shovel capable of reducing energy consumption during maintenance of a shovel including air bleeding from a refrigerant circuit through which a refrigerant for cooling a motor that drives a hydraulic pump circulates.SOLUTION: A shovel comprises: a motor (an electric motor 12 for a pump) driving a hydraulic pump; a refrigerant circuit 66 through which a refrigerant flows to cool objects to be cooled including the motor; a refrigerant pump (a water pump 64) circulating the refrigerant through the refrigerant circuit 66; and a control device for controlling an operation of the motor and the refrigerant pump. The control device is configured to be capable of switching between a normal mode in which the refrigerant pump is operated with the motor operating, and a maintenance mode in which the refrigerant pump is operated with the motor stopped.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a shovel.

Background Art

[0002] Conventionally, a work vehicle including an engine cooling water circuit and a branch path has been known (for example, Patent Document 1). The engine cooling water circuit includes a water pump that circulates engine cooling water for cooling the engine through a circulation path by driving the engine. Further, the branch path is provided for heat exchange between the engine cooling water and a reducing agent in a reducing agent tank.

[0003] In the work vehicle of Patent Document 1, when engine cooling water is supplied to the branch path, air in the path of the branch path is pushed out into the circulation path, and the air in the path is discharged into the outside air in a radiator connected to the circulation path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described work vehicle, in order to supply engine cooling water to the branch path by the water pump, it is necessary to drive the engine. Further, a thermostat that opens when the engine cooling water reaches a predetermined temperature and closes when the engine cooling water is below the predetermined temperature is provided in the circulation path. The water pump circulates engine cooling water through the circulation path and the branch path via this thermostat.

[0006] Therefore, after starting the engine, the above work vehicle cannot push out the air in the branch path until the engine coolant reaches a predetermined temperature, increasing the energy consumption during air bleeding. Further, in order to increase the supply pressure of the engine coolant by the water pump, it is necessary to increase the engine speed, further increasing the energy consumption during air bleeding.

[0007] Therefore, it is desirable to provide a work machine capable of reducing energy consumption during maintenance including air bleeding of a refrigerant circuit in which a refrigerant for cooling a prime mover that drives a hydraulic pump circulates.

Means for Solving the Problems

[0008] An excavator according to an embodiment of the present disclosure includes a lower traveling body, an upper swing body rotatably mounted on the lower traveling body, a hydraulic actuator that drives a driven part including the lower traveling body and the upper swing body, a hydraulic pump that supplies hydraulic oil to the hydraulic actuator, a prime mover that drives the hydraulic pump, a refrigerant circuit through which a refrigerant that cools a cooling target including the prime mover flows, a refrigerant pump that circulates the refrigerant through the refrigerant circuit, and a control device that controls the operations of the prime mover and the refrigerant pump. The control device is configured to be switchable between a normal mode in which the refrigerant pump is operated with the prime mover operating and a maintenance mode in which the refrigerant pump is operated with the prime mover stopped.

Advantages of the Invention

[0009] According to the above embodiment, it is possible to provide an excavator capable of reducing energy consumption during maintenance of the excavator including air bleeding of a refrigerant circuit in which a refrigerant for cooling a prime mover that drives a hydraulic pump circulates.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying out the Invention

[0011] Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings.

[0012] [Outline of Excavator] First, with reference to FIG. 1, the outline of an excavator 100 as an example of a working machine will be described.

[0013] FIG. 1 is a side view showing an example of the excavator 100 according to the present embodiment. The excavator 100 includes a lower traveling body 1, an upper slewing body 3 that is mounted on the lower traveling body 1 so as to be slewing-capable (slewing freely) via a slewing mechanism 2, an attachment AT, and a cabin 10 on which an operator rides. Incidentally, as will be described later, when the excavator 100 is remotely operated or operates in a fully automatic operation, the cabin 10 may be omitted.

[0014] The lower traveling body 1 includes, for example, a pair of left and right crawlers 1C (an example of a driven part). The lower traveling body 1 travels by itself when each crawler 1C is hydraulically driven by traveling hydraulic motors 1A and 1B (see FIG. 2).

[0015] The upper slewing body 3 (an example of a driven part) is hydraulically driven by a slewing hydraulic motor 2A through the slewing mechanism 2 (see FIG. 2).

[0016] The attachment AT includes a boom 4, an arm 5, and a bucket 6.

[0017] The boom 4 (an example of a driven part) is pivotally attached to the center of the front part of the upper swing body 3 so as to be able to pitch. At the tip of the boom 4, an arm 5 (an example of a driven part) is pivotally attached so as to be able to rotate vertically, and at the tip of the arm 5, a bucket 6 (an example of a driven part) is pivotally attached so as to be able to rotate vertically. The boom 4, the arm 5, and the bucket 6 are each hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators.

[0018] The bucket 6 is an example of an end attachment and is used for excavation work, compaction work, etc.

[0019] In addition, at the tip of the arm 5, other end attachments may be attached instead of the bucket 6 according to the work content, etc. The other end attachments may be, for example, buckets of a different type from the bucket 6 such as a slope bucket, a dredging bucket, etc. Also, the other end attachments may be, for example, end attachments of a different type from the bucket such as a breaker, a stirrer, a grappler, etc. Further, an auxiliary attachment such as a quick coupling or a tilt rotator may be provided at the connecting part between the end attachment including the bucket 6 and the arm 5.

[0020] In this example, as will be described later, in the excavator 100, all driven parts are hydraulically driven by hydraulic oil supplied from a main pump 14 (see Figure 2) that uses an electric motor for pump 12 (an example of a prime mover) as a power source. That is, in this example, the excavator 100 corresponds to a configuration in which an internal combustion engine (an example of a prime mover) of a so-called hydraulic excavator is replaced with an electric motor for pump 12 (an example of an electric motor).

[0021] In addition, part or all of the driven parts of the excavator 100 may be electrically driven. For example, the upper swing body 3 may rotate with respect to the lower traveling body 1 by being electrically driven by a swing electric motor through the swing mechanism 2.

[0022] The cab 10 is mounted, for example, on the front left side of the upper revolving body 3, and inside it, there are provided a driver's seat on which an operator sits, an operation device 26 described later, and the like.

[0023] In addition, as will be described later, when the excavator 100 is remotely operated or operates in a fully automatic operation mode, the cab 10 may be omitted.

[0024] The excavator 100 operates driven parts such as the lower traveling body 1 (left and right crawlers 1C), the upper revolving body 3, the boom 4, the arm 5, and the bucket 6 according to the operations of the operator boarding the cab 10.

[0025] Alternatively, or in addition to being configured to be operable by an operator boarding the cab 10, the excavator 100 may be configured to be remotely operable (remote operation) from outside the excavator 100. When the excavator 100 is remotely operated, the inside of the cab 10 may be unmanned. Hereinafter, the description will proceed on the premise that the operations of the operator include at least one of the operations on the operation device 26 of the operator in the cab 10 and the remote operations of the external operator.

[0026] Remote operation includes, for example, a mode in which the excavator 100 is operated by an operation input related to an actuator of the excavator 100 performed by a predetermined external device. The external device includes, for example, a management device that manages the excavator 100, a terminal device (user terminal) used by a user of the excavator 100, and the like. The same may apply to the remote monitoring described later. In this case, the excavator 100 is equipped with a communication device capable of communicating with the external device, and for example, an image (hereinafter, "peripheral image") representing the state of the surroundings of the excavator 100 based on the image information (captured image) output by the imaging device included in the peripheral information acquisition device 40 described later may be transmitted to the external device. Then, the external device may display the peripheral image of the excavator 100 received by a display device (hereinafter, "remote operation display device") provided in the external device. Also, various information images (information screens) displayed on the output device 50 (display device) inside the cab 10 of the excavator 100 may be similarly displayed on the remote operation display device of the external device. Thereby, an operator of the external device can remotely operate the excavator 100 while checking the display contents such as the peripheral image and information screen of the excavator 100 displayed on the remote operation display device. And the excavator 100 operates the actuator according to a remote operation signal representing the content of the remote operation received from the external device by the communication device, and may drive driven parts such as the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, and the bucket 6.

[0027] In addition, remote operation may include, for example, a mode in which the excavator 100 is operated by an external voice input or gesture input from a person (for example, an operator) around the excavator 100 to the excavator 100. Specifically, the excavator 100 recognizes voices spoken by surrounding workers or gestures made by workers through a voice input device (for example, a microphone) or a gesture input device (for example, an imaging device) mounted on the excavator 100 (itself). And the excavator 100 may operate the actuator according to the content of the recognized voice, gesture, etc., and drive driven parts such as the lower traveling body, the upper swing body 3, the boom 4, the arm 5, and the bucket 6.

[0028] In addition, the excavator 100 may automatically operate the actuator regardless of the content of the operator's operation. Thereby, the excavator 100 realizes a function of automatically operating at least a part of the driven parts such as the lower traveling body 1, the upper revolving body 3, the boom 4, the arm 5, and the bucket 6 (so-called "automatic operation function" or "MC (Machine Control) function").

[0029] The automatic operation function may include a function of automatically operating a driven part (actuator) other than the driven part (actuator) to be operated in response to an operation on the operator's operation device 26 or a remote operation (so-called "semi-automatic operation function" or "operation support type MC function"). Further, the automatic operation function may include a function of automatically operating at least a part of a plurality of driven parts (actuators) on the premise that there is no operation on the operator's operation device 26 or a remote operation (so-called "fully automatic operation function" or "fully automatic type MC function"). In the excavator 100, when the fully automatic operation function is valid, the inside of the cab 10 may be unmanned. Further, the semi-automatic operation function, the fully automatic operation function, etc. may include a mode in which the operation content of the driven part (actuator) to be automatically operated is automatically determined according to a rule defined in advance. Further, the semi-automatic operation function, the fully automatic operation function, etc. may include a mode (so-called "autonomous operation function") in which the excavator 100 autonomously makes various determinations and the operation content of the driven part (actuator) to be automatically operated is determined autonomously according to the determination result.

[0030] In addition, when the excavator 100 operates in the automatic operation function (particularly, the fully automatic operation function), the working condition of the excavator 100 may be remotely monitored from outside the excavator 100.

[0031] When remote monitoring is performed, the excavator 100 is equipped with a communication device capable of communicating with an external device. For example, an image (peripheral image) representing the state of the surroundings of the excavator 100 based on the image information output by the imaging device included in the peripheral information acquisition device 40 described later may be transmitted to the external device. Then, the external device may display the received image information (captured image) on a display device provided in the external device (hereinafter, "remote monitoring display device"). Also, various information images (information screens) displayed on the output device 50 (display device) inside the cab 10 of the excavator 100 may similarly be displayed on the remote monitoring display device of the external device. Thereby, a monitor of the external device can remotely monitor the working condition of the excavator 100 while checking the display contents such as the peripheral image and information screen of the excavator 100 displayed on the remote monitoring display device. Further, when there is some problem in the working condition of the excavator 100, for example, the monitor of the external device may be able to perform a predetermined input to the external device to cause the excavator 100 to stop suddenly or to perform an intervention operation on the excavator 100. In this case, the excavator 100 may stop the actuators in response to a signal indicating sudden stop received from the external device through the communication device, thereby suddenly stopping the driven parts such as the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6. Also, the excavator 100 may realize an intervention operation of the driven parts such as the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6 by operating the actuators in response to a signal representing the content of the intervention operation received from the external device through the communication device.

[0032] [Configuration of Excavator] Next, in addition to FIG. 1, with reference to FIGS. 2 to 6, the configuration of the excavator 100 according to the present embodiment will be described.

[0033] FIG. 2 is a block diagram schematically showing an example and other examples of the configuration of the excavator 100 according to the present embodiment. FIGS. 3 and 4 are diagrams showing an example of the cooling devices 60, 60A, 60B mounted on the excavator 100 according to the present embodiment. FIGS. 5 and 6 are flowcharts showing an example of the operation of the control device 30 mounted on the excavator 100 of the present embodiment.

[0034] Also, in FIG. 2, the mechanical power transmission system is represented by a double line, the relatively high hydraulic pressure transmission system, i.e., the hydraulic line of the hydraulic drive system, is represented by a thick solid line, the pilot pressure transmission system, i.e., the hydraulic line of the operating system, is represented by a dashed line, and the power and electrical signal transmission systems are represented by thin solid lines, respectively.

[0035] The excavator 100 includes respective components such as a hydraulic drive system, an electric drive system, a power supply system, an operating system, a cooling system, a user interface system, a comfort equipment system, and a control system.

[0036] <Hydraulic drive system> The hydraulic drive system of the excavator 100 is a group of components related to the hydraulic drive of the driven parts.

[0037] The hydraulic drive system of the excavator 100 includes hydraulic actuators such as travel hydraulic motors 1A, 1B that hydraulically drive respective driven parts such as the lower traveling body 1, the boom 4, the arm 5, and the bucket 6, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9. Also, the hydraulic drive system of the excavator 100 includes a pump motor 12, a main pump 14, and a control valve 17.

[0038] The pump motor 12 (an example of a prime mover and an electric motor) is a power source of the hydraulic drive system. The pump motor 12 is, for example, an IPM (Interior Permanent Magnet) motor. The pump motor 12 is connected to the power storage device 19 via the inverter 18. The pump motor 12 performs power running with three-phase AC power supplied from the power storage device 19 via the inverter 18 and drives the main pump 14 and the pilot pump 15. The drive control of the pump motor 12 may be executed by the inverter 18 under the control of a control device 30 described later.

[0039] The main pump 14 (an example of a hydraulic pump) sucks hydraulic oil from the hydraulic oil tank T and discharges it into the high-pressure hydraulic line 16, thereby supplying hydraulic oil to the control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by the pump motor 12 as described above. The main pump 14 is, for example, a variable displacement hydraulic pump, and under the control of a control device 30 described later, a regulator (not shown) controls the angle of the swash plate (tilt angle). Thereby, the main pump 14 can adjust the stroke length of the piston and adjust the discharge flow rate (discharge pressure).

[0040] The control valve 17 controls the hydraulic drive system in response to an operation by the operator or an operation command corresponding to the automatic operation function. As described above, the control valve 17 is connected to the main pump 14 via the high-pressure hydraulic line 16, and is configured to selectively supply the hydraulic oil supplied from the main pump 14 to a plurality of hydraulic actuators. For example, the control valve 17 is a valve unit including a plurality of control valves (direction change valves) that control the flow rate and flow direction of the hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators. The hydraulic oil supplied from the main pump 14 and flowing through the control valve 17 and the hydraulic actuator is discharged from the control valve 17 to the hydraulic oil tank T.

[0041] <Electric drive system> The electric drive system of the excavator 100 is a group of components related to the electric drive of the prime mover (power source) and the driven parts of the excavator 100.

[0042] As shown in FIG. 2, the electric drive system of the excavator 100 includes a pump motor 12, a sensor 12s, and an inverter 18.

[0043] In addition, as described above, when a part or all of the driven parts of the excavator 100 are electrically driven, the electric drive system of the excavator 100 may include an electric actuator that drives the driven part, an inverter that drives the electric actuator, and the like.

[0044] The sensor 12s includes a current sensor 12s1, a voltage sensor 12s2, and a rotation state sensor 12s3.

[0045] The current sensor 12s1 detects the current of each of the three phases (U phase, V phase, and W phase) of the pump motor 12. The current sensor 12s1 is provided, for example, in the power path between the pump motor 12 and the inverter 18. The detection signals corresponding to the currents of the three phases of the pump motor 12 detected by the current sensor 12s1 are directly taken into the inverter 18 through the communication line. Further, the detection signals may be taken into the control device 30 through the communication line and input to the inverter 18 via the control device 30.

[0046] The voltage sensor 12s2 detects the applied voltage of each of the three phases of the pump motor 12. The voltage sensor 12s2 is provided, for example, in the power path between the pump motor 12 and the inverter 18. The detection signals corresponding to the applied voltages of the three phases of the pump motor 12 detected by the voltage sensor 12s2 are directly taken into the inverter 18 through the communication line. Further, the detection signals may be taken into the control device 30 through the communication line and input to the inverter 18 via the control device 30.

[0047] The rotation state sensor 12s3 detects the rotation state of the pump motor 12. The rotation state of the pump motor 12 includes, for example, the rotation position (rotation angle), the rotation speed, and the like. The rotation state sensor 12s3 is, for example, a rotary encoder or a resolver. The detection signals corresponding to the rotation state of the pump motor 12 detected by the rotation state sensor 12s3 are directly taken into the inverter 18 through the communication line. Further, the detection signals may be taken into the control device 30 through the communication line and input to the inverter 18 via the control device 30.

[0048] The inverter 18 drives and controls the pump motor 12 under the control of the control device 30. The inverter 18 includes, for example, a conversion circuit that converts DC power into three-phase AC power or converts three-phase AC power into DC power, a drive circuit that drives the conversion circuit by switching, and a control circuit that outputs a control signal that defines the operation of the drive circuit. The control signal is, for example, a PWM (Pulse Width Modulation) signal.

[0049] The control circuit of the inverter 18 performs drive control of the pump motor 12 while grasping the operating state of the pump motor 12. For example, the control circuit of the inverter 18 grasps the operating state of the pump motor 12 based on the detection signal of the rotation state sensor 12s3. Further, the control circuit of the inverter 18 may grasp the operating state of the pump motor 12 by sequentially estimating the rotation angle of the rotating shaft of the pump motor 12 based on the detection signal of the current sensor 12s1 and the detection signal of the voltage sensor 12s2 (or the voltage command value generated during the control process).

[0050] Note that at least one of the drive circuit and the control circuit of the inverter 18 may be provided outside the inverter 18.

[0051] <Power supply system> The power supply system of the excavator 100 is a group of components for supplying power to various electrical devices.

[0052] As shown in FIG. 2, the power supply system of the excavator 100 includes a power storage device 19, a DC-DC converter 44, a battery 46, an in-vehicle charger 70, and a charging port 72.

[0053] The power storage device 19 is an energy source for driving the actuator of the excavator 100. The power storage device 19 is charged (stores electricity) by being connected to an external commercial power supply with a predetermined cable (hereinafter, "charging cable"), and supplies the charged power to the pump motor 12. The power storage device 19 is, for example, a lithium-ion battery and has a relatively high output voltage (for example, several hundred volts).

[0054] Further, a power conversion device may be provided between the power storage device 19 and the pump motor 12 to boost the output voltage of the power storage device 19 and apply it to the pump motor 12. Also, as described above, when a part or all of the driven part is electrically driven, the power of the power storage device 19 is supplied to an electric actuator that electrically drives the driven part instead of or in addition to the pump motor 12.

[0055] The DC-DC converter 44 (an example of a power conversion device) is provided, for example, on the upper swing body 3, and steps down the very high voltage DC power output from the power storage device 19 to a predetermined voltage (for example, about 24 volts) and outputs it. The output power of the DC-DC converter 44 is supplied to the battery 46 to be charged (stored) or supplied to electrical equipment (hereinafter, "low-voltage equipment") driven by the power of the battery 46. The low-voltage equipment includes, for example, the control device 30. Also, the low-voltage equipment includes, for example, a water pump 64, an air conditioner (not shown), a cooling fan 90, etc. described later.

[0056] For example, as shown in FIG. 2, the excavator 100 is equipped with one DC-DC converter 44.

[0057] Also, although not shown, the DC-DC converter 44 may include a plurality of DC-DC converters connected in parallel. Thereby, the plurality of DC-DC converters can share and output the current required by the low-voltage equipment. Also, since each of the plurality of DC-DC converters has a relatively small current capacity, that is, the maximum value of the outputtable current, the external dimensions are also relatively small. Therefore, the degree of freedom in arrangement when mounted on the upper swing body 3 can be improved. Also, even if any one of the plurality of DC-DC converters becomes unable to supply power due to an abnormality or the like, the power supply from the other can be continued.

[0058] Furthermore, the DC-DC converter 44 may be replaced by an alternator. In this case, the alternator may be provided on the upper swing body 3 and generate electricity using the power of the pump motor 12. Similar to the case of the DC-DC converter 44, the generated power of the alternator is supplied to the battery 46, and the battery 46 is charged (electricity is stored) or supplied to low-voltage devices such as the control device 30.

[0059] The battery 46 is provided on the upper swing body 3 and has a relatively low output voltage (for example, 24 volts). The battery 46 supplies power to low-voltage devices other than the electric drive system that require relatively high power. The battery 46 is, for example, a lead-acid battery, a lithium-ion battery, etc., and is charged with the output power of the DC-DC converter 44 as described above.

[0060] The in-vehicle charger 70 charges the power storage device 19 by converting single-phase AC power with a relatively low voltage (for example, 100 volts or 200 volts) supplied from an external power source into DC power through a charging port 72A described later and outputting it to the power storage device 19.

[0061] The charging port 72 is provided, for example, on the side surface of the upper swing body 3, etc., and is connected by inserting the tip of a charging cable extending from an external power source. The charging port 72 includes charging ports 72A and 72B.

[0062] The charging port 72A is configured to be connectable to a charging cable extending from an external power source (for example, a commercial power source) that can supply single-phase AC power with a relatively low voltage. The charging port 72A is connected to the in-vehicle charger 70 by a power line (wire harness), and the power supplied from the external power source is supplied to the power storage device 19 through the in-vehicle charger 70. Thereby, so-called normal charging of the power storage device 19 is realized.

[0063] To the charging port 72B, for example, a charging cable extending from an external power source capable of supplying DC power at a relatively high voltage (e.g., 400 volts) is connected. The charging port 72B is directly connected to the power storage device 19 by a power line (wire harness) and directly supplies the DC power supplied from the external power source to the power storage device 19. Thereby, so-called rapid charging of the power storage device 19 is realized.

[0064] <Operating system> The operating system of the excavator 100 is a group of components related to the operation of the driven part.

[0065] As shown in FIG. 2, the operating system of the excavator 100 includes a pilot pump 15, an operating device 26, and a hydraulic control valve 31. Although not shown, the operating system of the excavator 100 includes a gate lock valve, a gate lock switch, and a relay. Further, in addition to the relay, the operating system of the excavator 100 may include a switching valve.

[0066] The pilot pump 15 (an example of a second hydraulic pump) supplies pilot pressure to various hydraulic devices (e.g., the hydraulic control valve 31) mounted on the excavator 100 via the pilot line 25. Thereby, the hydraulic control valve 31 can supply a pilot pressure corresponding to the operation content (e.g., operation amount and operation direction) of the operating device 26 to the control valve 17 under the control of the control device 30. Therefore, the control device 30 and the hydraulic control valve 31 can realize the operation of the driven part (hydraulic actuator) corresponding to the operation content of the operator on the operating device 26. Further, the hydraulic control valve 31 can supply a pilot pressure corresponding to the content of the remote operation specified by the remote operation signal to the control valve 17 under the control of the control device 30. Further, the hydraulic control valve 31 can supply a pilot pressure corresponding to the operation command corresponding to the automatic operation function to the control valve 17 under the control of the control device 30. The pilot pump 15 is, for example, a fixed displacement hydraulic pump and is driven by the pump motor 12 as described above.

[0067] Further, the pilot pump 15 may be omitted. In this case, the various hydraulic devices such as the hydraulic control valve 31 may be supplied with the hydraulic oil discharged from the main pump 14 and decompressed to a predetermined pilot pressure via a pressure reducing valve or the like.

[0068] The operating device 26 is provided within reach of the operator at the driver's seat in the cabin 10 and is used for the operator to operate each driven part (i.e., the left and right crawlers 1C of the lower traveling body 1, the upper swing body 3, the boom 4, the arm 5, and the bucket 6, etc.). In other words, the operating device 26 is used for the operator to operate the actuators (e.g., the traveling hydraulic motors 1A, 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9, etc.) that drive each driven part. For example, as shown in FIG. 2, the operating device 26 is electric and outputs an electric signal (hereinafter, "operation signal") corresponding to the operation content by the operator. The operation signal output from the operating device 26 is taken into the control device 30. Thereby, the control device 30 can control the hydraulic control valve 31, etc., and control the operation of the driven part (actuator) of the excavator 100 according to the operation content of the operator and the operation commands corresponding to the automatic operation function.

[0069] The operating device 26 includes, for example, levers 26A to 26C. The lever 26A may be configured to be able to receive operations related to each of the arm 5 (arm cylinder 8) and the upper swing body 3 (swing operation) according to operations in the front-rear direction and the left-right direction. The lever 26B may be configured to be able to receive operations related to each of the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) according to operations in the front-rear direction and the left-right direction. The lever 26C may be configured to be able to receive operations of the lower traveling body 1 (crawler 1C).

[0070] When the control valve 17 is composed of an electromagnetic pilot-operated hydraulic control valve (direction change valve), the operation signal of the electric operating device 26 may be directly input to the control valve 17, and each hydraulic control valve may operate according to the operation content of the operating device 26. Further, the operating device 26 may be a hydraulic pilot type that outputs a pilot pressure according to the operation content. In this case, the pilot pressure according to the operation content is supplied to the control valve 17.

[0071] The hydraulic control valve 31 outputs a predetermined pilot pressure using the hydraulic oil supplied from the pilot pump 15 through the pilot line 25 under the control of the control device 30. The pilot line on the secondary side of the hydraulic control valve 31 is connected to the control valve 17, and the pilot pressure output from the hydraulic control valve 31 is supplied to the control valve 17.

[0072] The gate lock valve (not shown) is a switching valve provided in the pilot line 25. The gate lock valve is, for example, an electromagnetic solenoid valve. In the non-energized state, the gate lock valve makes the pilot line 25 in a non-connected state. In this case, the gate lock valve discharges the hydraulic oil in the downstream pilot line 25 to the hydraulic oil tank T. On the other hand, in the energized state, the gate lock valve makes the pilot line 25 in a connected state. In this case, the gate lock valve supplies the hydraulic oil of the pilot pump 15 to the downstream side.

[0073] The gate lock switch (not shown) is provided on the power line between the battery 46 and the gate lock valve (electromagnetic solenoid). When the gate lock switch is in the off state, it opens the power line and makes the gate lock valve in the non-energized state. When it is in the on state, it closes the power line and makes the gate lock valve in the energized state.

[0074] The gate lock switch is turned on and off according to the operation state of the gate lock lever inside the cabin 10. The gate lock switch is, for example, a limit switch interlocked with the operation of the gate lock lever.

[0075] The gate lock switch turns off when it is in an operating state corresponding to the state where the gate bar is pulled up, that is, the operator's seat in the cabin 10 is opened for boarding and alighting. Thereby, when the gate bar is pulled up, the gate lock valve maintains the pilot line 25 in a non-communication state. Therefore, the gate lock switch can operate the gate lock valve so that pilot pressure is not supplied to the hydraulic control valve 31 according to a situation where there is no intention to operate by the operator in the cabin 10 or a situation where there is no operator in the cabin 10. On the other hand, the gate lock switch turns on when it is in an operating state corresponding to the state where the gate bar is lowered, that is, the operator's seat in the cabin 10 is closed so that boarding and alighting are impossible. Thereby, the gate lock switch can operate the gate lock valve so that pilot pressure is supplied to the hydraulic control valve 31 according to a situation where the operator in the cabin 10 has the intention to operate.

[0076] A relay (not shown) is used to cut off (non-connect) the pilot line 25 regardless of the operating state of the gate lock lever, that is, the state of the gate lock switch.

[0077] For example, the relay is arranged on the power line between the battery 46 and the gate lock valve (electromagnetic solenoid). In this case, the relay is of the normally closed type and is opened when energized by a control current input from the control device 30. Thereby, the control device 30 can energize the relay and open the relay to make the gate lock valve non-energized and shift the pilot line 25 to a non-communication state even when the gate lock switch is in the on state. Therefore, the control device 30 can stop the operation of the driven part (hydraulic actuator).

[0078] Also, for example, the relay may be provided on the power line between the battery 46 and the switching valve (electromagnetic solenoid). In this case, the relay is of the normally open type and is closed when energized by a control current input from the control device 30.

[0079] The switching valve (not shown) is provided in the pilot line 25. For example, the switching valve may be provided downstream of the gate lock valve in the pilot line 25, or may be provided upstream of the gate lock. The switching valve is, for example, an electromagnetic solenoid valve. Similar to the gate lock valve, the switching valve keeps the pilot line 25 in a communicating state when de-energized. On the other hand, the switching valve makes the pilot line 25 in a non-communicating state when energized.

[0080] When the coil of the relay is de-energized, the relay is released, so the switching valve maintains the pilot line 25 in a communicating state. On the other hand, when the coil of the relay is energized by the control device 30, the relay is closed, so the switching valve maintains the pilot line 25 in a non-communicating state. Thereby, even when the gate lock valve is in a communicating state, the control device 30 can shift the switching valve to a non-communicating state. Therefore, the control device 30 can stop the operation of the driven part (hydraulic actuator).

[0081] Note that the relay and the switching valve may be omitted. In this case, the control device 30 may limit the operation of the driven part (hydraulic actuator) by controlling, for example, the pilot pressure output from the hydraulic control valve 31. <Cooling system> The cooling system of the excavator 100 is a group of components for cooling the components that generate heat during the operation of the excavator 100.

[0082] As shown in FIG. 3, the cooling system of the excavator 100 includes a cooling device 60 and a cooling fan 90. Also, as shown in FIG. 4, the cooling system of the excavator 100 may include a plurality of cooling devices 60A, 60B and a plurality of cooling fans 90A, 90B.

[0083] The cooling device 60 cools the equipment of the electric drive system and the equipment of the power supply system with a relatively high voltage in the excavator 100. For example, as shown in FIG. 3, the equipment to be cooled by the cooling device 60 includes the pump motor 12, the inverter 18, the energy storage device 19, the DC-DC converter 44, etc. Note that the object to be cooled may include the in-vehicle charger 70 shown in FIG. 2.

[0084] Note that as long as the conditions regarding the required cooling performance for each of the plurality of objects to be cooled are satisfied, the connection mode in the refrigerant circuit 66 of the object to be cooled configured such that the refrigerant can pass around or inside thereof by the refrigerant circuit 66 may be arbitrary. That is, as long as the conditions regarding the required cooling performance for each of the plurality of objects to be cooled are satisfied, some or all of the plurality of objects to be cooled cooled by the refrigerant circuit 66 may be connected in series, or some or all of them may be connected in parallel. Also, as long as the conditions regarding the required cooling performance for each of the plurality of objects to be cooled are satisfied, the order of arrangement of the plurality of objects to be cooled starting from the radiator 62 in the refrigerant circuit 66 may be arbitrary.

[0085] The cooling device 60 shown in FIG. 3 includes a radiator 62, a water pump 64, and a refrigerant circuit 66. Also, the cooling device 60 may include a reserve tank 68.

[0086] Note that the plurality of cooling devices 60A and 60B shown in FIG. 4 have the same configuration as the cooling device 60 shown in FIG. 3 except that the objects to be cooled by the respective cooling devices 60A and 60B are different. Therefore, in FIG. 4, for the same configuration as the cooling device 60 in FIG. 3, reference numerals obtained by adding A and B corresponding to the cooling devices 60A and 60B to the reference numerals of each configuration of the cooling device 60 in FIG. 3 are used, and duplicate explanations are omitted.

[0087] The radiator 62 cools the refrigerant (for example, cooling water) in the refrigerant circuit 66. Specifically, the radiator 62 causes heat exchange between the surrounding air and the refrigerant to cool the refrigerant.

[0088] The water pump 64 (an example of a refrigerant pump) circulates the refrigerant within the refrigerant circuit 66. The water pump 64 operates, for example, on electric power supplied from the DC-DC converter 44 or the battery 46.

[0089] The reserve tank 68 is connected, for example, to the radiator cap 62c via a tube, and replenishes the radiator 62 with refrigerant or receives the refrigerant flowing out from the radiator 62 in response to increases and decreases in volume and pressure due to temperature changes of the refrigerant inside the radiator 62.

[0090] In the cooling device 60 shown in FIG. 3, the upstream end of the refrigerant circuit 66 is connected to the refrigerant outlet of the radiator 62, and the downstream end of the refrigerant circuit 66 is connected to the refrigerant inlet of the radiator 62. The refrigerant circuit 66 cools the power storage device 19, the DC-DC converter 44, the inverter 18, and the pump motor 12, which are objects to be cooled, by heat exchange with the refrigerant. The objects to be cooled are arranged in the order of the power storage device 19, the DC-DC converter 44, the inverter 18, and the pump motor 12 from the upstream end side to the downstream end side of the refrigerant circuit 66.

[0091] The refrigerant circuit 66 connects each object to be cooled in series or in parallel, for example, by connecting to the inlets and outlets of the refrigerant flow paths provided inside or around each object to be cooled. The refrigerant circuit 66 circulates the refrigerant to pass the refrigerant through the refrigerant flow paths of each object to be cooled and cools each object to be cooled. The refrigerant that has been heated by cooling each object to be cooled flows from the downstream end of the refrigerant circuit 66 into the refrigerant inlet of the radiator 62, is cooled by the radiator 62, and its temperature decreases. The refrigerant cooled by the radiator 62 flows from the refrigerant outlet of the radiator 62 into the upstream end of the refrigerant circuit 66, and is pumped by the water pump 64 provided on the upstream end side of the refrigerant circuit 66 rather than each object to be cooled to circulate through the refrigerant circuit 66.

[0092] Similarly, in the cooling device 60A shown in FIG. 4, the refrigerant circuit 66A cools the DC-DC converter 44, the inverter 18, and the pump motor 12, which are objects to be cooled, by circulating the refrigerant through heat exchange with the refrigerant. The objects to be cooled are arranged in the order of the DC-DC converter 44, the inverter 18, and the pump motor 12 from the upstream side to the downstream side of the refrigerant flowing through the refrigerant circuit 66A. Further, in the cooling device 60B shown in FIG. 4, the refrigerant circuit 66B cools the power storage device 19, which is an object to be cooled, by circulating the refrigerant through heat exchange with the refrigerant.

[0093] In addition, when a power conversion device is provided between the power storage device 19 and the pump motor 12, the power conversion device may be cooled by the cooling device 60. In this case, the power conversion device may be arranged in parallel with the inverter 18 and the DC-DC converter 44 in the refrigerant circuit 66, for example, and cooled by the refrigerant flowing out from the power storage device 19. Further, the DC-DC converter 44 may be air-cooled. In this case, the DC-DC converter 44 is excluded from the objects to be cooled by the cooling device 60. Also, at least a part of the inverter 18 and the DC-DC converter 44 may be arranged in parallel in the refrigerant circuit 66.

[0094] The cooling fan 90 operates under the control of the control device 30 and blows air toward a predetermined device (hereinafter, "heat exchange device") that performs heat exchange with air. The cooling fan 90 operates, for example, with the power supplied from the DC-DC converter 44 or the battery 46. The cooling fan 90 may blow air toward the radiator 62, for example, as shown in FIG. 3, to cool the radiator 62. As a result, air capable of performing heat exchange with the refrigerant flowing through the inside is sequentially supplied around the radiator 62, and the degree of cooling of the refrigerant by the radiator 62 can be increased.

[0095] <User interface system> The user interface system of the excavator 100 is a group of components related to the exchange of information with the user.

[0096] As shown in FIG. 2, the user interface system includes an output device 50 and an input device 52.

[0097] The output device 50 (an example of a notification device) outputs various types of information to the user under the control of the control device 30. For example, the output device 50 includes an output device provided inside the cabin 10 that outputs various types of information to a user (e.g., an operator) inside the cabin 10. Also, for example, the output device 50 may include an output device provided outside the cabin 10 that outputs various types of information to a user (e.g., a worker or supervisor around the excavator 100) around the excavator 100.

[0098] The output device 50 includes, for example, a display device, a lighting device, etc. that output (notify) information to the user in a visual manner. The display device may display various information images under the control of the control device 30. The display device is, for example, a liquid crystal display, an organic EL (Electroluminescence) display, etc. The lighting device is, for example, a warning light, etc.

[0099] Also, the output device 50 includes, for example, a sound output device that outputs information to the user in an auditory manner. The sound output device is, for example, a buzzer, a speaker, etc.

[0100] The input device 52 receives various inputs from the user. For example, the input device 52 includes an input device provided inside the cabin 10 that receives various inputs from a user (e.g., an operator) inside the cabin 10. Also, for example, the input device 52 may include an input device provided outside the cabin 10 that receives various inputs from a user (e.g., a worker or supervisor around the excavator 100) outside the cabin 10.

[0101] The input device 52 may include, for example, an operation input device that receives operation inputs from a user. The operation input device may include, for example, buttons, toggles, levers, touch panels, touch pads, etc. Further, the input device 52 may also include, for example, a voice input device that receives voice inputs from an operator or a gesture input device that receives gesture inputs from the operator. The voice input device includes, for example, a microphone that acquires the user's voice. Also, the gesture input device includes, for example, a camera that can image the state of the user's gestures. A signal corresponding to the input from the operator received by the input device 52 is taken into the control device 30.

[0102] <Comfort equipment system> The comfort equipment system of the excavator 100 is a group of components related to the comfort equipment of the user (operator) inside the cabin 10. The comfort equipment system of the excavator 100 includes an air conditioner (not shown).

[0103] <Control system> The control system of the excavator 100 is a group of components related to various controls of the excavator 100.

[0104] As shown in FIG. 2, the control system of the excavator 100 includes a control device 30. Further, the control system of the excavator 100 includes a peripheral information acquisition device 40, a sensor 48, and temperature sensors 54 and 56.

[0105] Various functions realized by the control device 30 may be realized by a single controller or may be distributed and realized by two or more appropriately set controllers.

[0106] The control device 30 may have each function realized by any hardware or any combination of hardware and software. For example, the control device 30 is mainly configured around 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), and an interface device for communication with the outside. The control device 30 realizes various functions, for example, by loading a program installed in the auxiliary storage device into the memory device and executing it on the CPU.

[0107] The control device 30 performs drive control of the excavator 100. For example, the control device 30 outputs a control command to the hydraulic control valve 31 according to an operation signal input from the operation device 26, and causes the hydraulic control valve 31 to output a pilot pressure corresponding to the operation content of the operation device 26. Thereby, the control device 30 can realize the operation of the driven part (hydraulic actuator) of the excavator 100 corresponding to the operation content of the electric operation device 26.

[0108] When the excavator 100 is remotely operated, the control device 30 may perform control related to remote operation, for example. Specifically, the control device 30 may output a control command to the hydraulic control valve 31 and cause the hydraulic control valve 31 to output a pilot pressure corresponding to the content of the remote operation. Thereby, the control device 30 can realize the operation of the driven part (hydraulic actuator) of the excavator 100 corresponding to the content of the remote operation.

[0109] The control device 30 may perform control related to the automatic operation function, for example. Specifically, the control device 30 may output a control command to the hydraulic control valve 31 and cause the pilot pressure corresponding to the operation command corresponding to the automatic operation function to act on the control valve 17 from the hydraulic control valve 31. Thereby, the control device 30 can realize the operation of the driven part (hydraulic actuator) of the excavator 100 corresponding to the automatic operation function.

[0110] Further, the control device 30 may integrally control the operations of the entire excavator 100 (various devices mounted on the excavator 100). For example, the control device 30 performs control related to the electric drive system based on a control command or the like including an operation signal of the operation device 26.

[0111] Further, for example, the control device 30 outputs a control command to the inverter 18 to perform drive control of the pump motor 12.

[0112] In addition, as described above, when a power conversion device is provided between the power storage device 19 and the pump motor 12, the control device 30 may output a control command to the power conversion device, for example, to perform control related to the operation of the power conversion device.

[0113] Further, the control device 30 performs control related to the peripheral monitoring function of the excavator 100.

[0114] For example, based on data regarding the situation of the three-dimensional space around the excavator 100, which is captured from the peripheral information acquisition device 40, the control device 30 detects a predetermined object (hereinafter, "monitoring object") around the excavator 100 or estimates the position of the monitoring object. The monitoring object includes, for example, a person. In addition, the monitoring object includes, for example, other work vehicles, other work machines, etc. Further, the monitoring object may include, for example, utility poles, pylons, fences, on-site materials, etc. The data regarding the situation of the three-dimensional space around the excavator 100 includes, for example, detection data regarding the objects around the excavator 100 and their positions.

[0115] Further, for example, when the control device 30 detects a monitoring object within a predetermined monitoring range, it outputs an alarm to the user in the cab 10 or to the surroundings of the excavator 100 through the output device 50 (for example, a display device, a sound output device, etc.). The monitoring range is appropriately set, for example, as a range where the distance from the excavator 100 to the surroundings of the excavator 100 is relatively close.

[0116] Further, when the control device 30 detects a monitored object within a predetermined monitoring range, for example, it may limit the operation of the driven part (actuator) of the excavator 100.

[0117] The limitation of the operation of the driven part includes, for example, the stop of the operation of the driven part. The control device 30 may forcibly stop the operation of the driven part (hydraulic actuator) by, for example, releasing the above-mentioned relay. Further, the control device 30 may forcibly stop the operation of the driven part (hydraulic actuator) by invalidating the operator's operation or operation command.

[0118] Also, the limitation of the operation of the driven part includes, for example, the deceleration of the operation of the driven part. The control device 30 may relatively reduce the pilot pressure output from the hydraulic control valve 31 to the control valve 17, and decelerate the operation of the driven part (hydraulic actuator) with respect to the operator's operation or operation command.

[0119] Further, the control device 30 performs control regarding the power storage device 19. The control device 30 performs control regarding the charging of the power storage device 19, for example. The control device 30 monitors various states of the power storage device 19 (for example, current state, voltage state, temperature state, charge state, deterioration state, presence or absence of abnormality, etc.) based on the outputs of various sensors built in the power storage device 19.

[0120] Further, the control device 30 performs control regarding the DC-DC converter 44. The control device 30 performs control regarding the operation of the DC-DC converter 44, for example. The control device 30 monitors various states of the DC-DC converter 44 (for example, current state, voltage state, temperature state, etc.).

[0121] The peripheral information acquisition device 40 outputs information regarding the situation of the three-dimensional space around the excavator 100. The peripheral information acquisition device 40 may include, for example, an ultrasonic sensor, a millimeter-wave radar, a monocular camera, a stereo camera, a depth camera, a LIDAR (Light Detection and Ranging), a distance image sensor, an infrared sensor, etc. The output information of the peripheral information acquisition device 40 is taken into the control device 30.

[0122] Incidentally, the peripheral monitoring function of the excavator 100 may be omitted. In this case, the peripheral information acquisition device 40 may be omitted.

[0123] The sensor 48 measures the state of the power supplied from the DC-DC converter 44 and the battery 46 to the low-voltage load. For example, the sensor 48 may include a current sensor that measures the current supplied from the DC-DC converter 44 and the battery 46 to the low-voltage load and a voltage sensor that measures the voltage.

[0124] The temperature sensor 54 measures (detects) the temperature of the equipment of the electric drive system to be cooled by the cooling device 60 described later. The temperature sensor 54 includes, for example, a temperature sensor that detects the temperature of the pump motor 12. Also, the temperature sensor 54 includes a temperature sensor that detects the temperature of the inverter 18. Also, the temperature sensor 54 includes, for example, a temperature sensor that detects the temperature of the power storage device 19. Also, the temperature sensor 54 includes, for example, a temperature sensor that detects the temperature of the DC-DC converter 44. Also, the temperature sensor 54 includes, for example, a temperature sensor that detects the temperature of the in-vehicle charger 70. The detection signal of the temperature sensor 54 is taken into the control device 30, for example. Thereby, the control device 30 can grasp the temperature state of the equipment of the electric drive system.

[0125] Incidentally, when a power conversion device is provided between the power storage device 19 and the pump motor 12, the temperature sensor may include a temperature sensor that grasps the temperature state of the power conversion device.

[0126] The temperature sensor 56 measures (detects) the indoor temperature of the cabin 10. The detection signal of the temperature sensor 56 is taken into, for example, the control device 30. Thereby, the control device 30 can grasp the temperature state inside the cabin 10.

[0127] FIG. 5 is a flowchart showing an example of the operation of the control device 30 that controls the cooling device 60 or the cooling devices 60A and 60B shown in FIGS. 3 and 4. As described above, the control device 30 controls the pump motor 12 as a prime mover that drives the main pump 14, which is a hydraulic pump, and the water pump 64 as a refrigerant pump that circulates the refrigerant in the refrigerant circuit 66. Details will be described later, but the control device 30 is configured to be able to switch between a normal mode in which the water pump 64 is operated with the pump motor 12 operating and a maintenance mode in which the water pump 64 is operated with the pump motor 12 stopped.

[0128] The normal mode is, for example, a mode selected during normal operation of the excavator 100, and is a mode for driving the lower traveling body 1, slewing the upper slewing body 3, or driving the attachment AT. The maintenance mode is, for example, a mode selected during maintenance of the excavator 100 including bleeding the refrigerant circuits 66, 66A, and 66B that constitute the cooling devices 60, 60A, and 60B.

[0129] When the start switch of the excavator 100 is turned on (for example, key ON operation) by, for example, a user (for example, an operator) of the excavator 100, the control device 30 starts the processing flow shown in FIG. 5 and executes the operation reception process P1. Further, when the start switch is turned on, the control device 30 may repeatedly execute processes P3 to P7 in the normal mode described later without executing processes P1 and P2. In this case, the user of the excavator 100 operates the input device 52, for example, during maintenance such as bleeding, to cause the control device 30 to start the processing flow in FIG. 5 and execute the operation reception process P1.

[0130] In this process P1, the control device 30 causes an image for selecting confirmation or cancellation of the maintenance mode to be displayed on, for example, an output device 50 (display device) within the cab 10 of the excavator 100 or a terminal device (user terminal) used by the user of the excavator 100. Further, the control device 30 receives an input for confirmation or cancellation of the maintenance mode from the user via, for example, the input device 52.

[0131] In this process P1, a user who cancels the confirmation of the maintenance mode and continues the normal operation of the excavator 100 inputs the cancellation of the maintenance mode to the input device 52. When the control device 30 receives an input for canceling the maintenance mode, that is, an input for continuing the normal mode, via the input device 52, for example, it operates the pump motor 12.

[0132] Specifically, the control device 30 transmits a control signal to, for example, the power storage device 19 and the inverter 18 shown in FIG. 2, supplies power from the power storage device 19 to the pump motor 12 via the inverter 18, and operates the pump motor 12. As a result, the main pump 14 and the pilot pump 15 are driven by the pump motor 12, and driven parts such as the lower traveling body 1, the upper slewing body 3, and the attachment AT can be driven by hydraulic actuators such as the traveling hydraulic motors 1A, 1B and the slewing hydraulic motor 2A. Further, the control device 30 controls the battery 46, the power storage device 19, the DC-DC converter 44, etc., and supplies power to the water pump 64, the cooling fan 90, etc.

[0133] On the other hand, a user who performs maintenance on the excavator 100 selects and inputs the confirmation of the maintenance mode in this process P1. Note that the maintenance of the excavator 100 includes, for example, bleeding the refrigerant circuits 66, 66A, 66B when injecting or replacing the refrigerant for the radiator 62 of the cooling device 60 in FIG. 3 or the radiators 62A, 62B of the cooling devices 60A, 60B in FIG. 4. The bleeding of these refrigerant circuits 66, 66A, 66B will be described later.

[0134] In this process P1, when the control device 30 receives an input for determining the maintenance mode via the input device 52, for example, it maintains the state in which the pump motor 12 is stopped. As a result, the main pump 14 and the pilot pump 15 also remain in the stopped state. Further, even in the maintenance mode, the control device 30 controls the battery 46, the power storage device 19, the DC-DC converter 44, etc. in the same manner as in the normal mode to supply power to the water pump 64, the cooling fan 90, etc.

[0135] After the end of the above-described operation reception process P1, the control device 30 executes, for example, a mode determination process P2.

[0136] In this process P2, the control device 30 determines whether or not the selection result of determining or canceling the maintenance mode input by the user in the previous process P1 is the determination of the maintenance mode. Specifically, for example, when the user selects "cancel maintenance mode" and inputs it to the input device 52 in the previous process P1, the control device 30 determines that the user's mode selection result is not the maintenance mode (NO), that is, it is the normal mode, and executes the next cooling determination process P3.

[0137] In this process P3, the control device 30 acquires, for example, the detection result of the temperature sensor 54. The detection result of the temperature sensor 54 includes, for example, the temperatures of the cooling targets of the cooling device 60 in FIG. 3 such as the power storage device 19, the DC-DC converter 44, the inverter 18, the pump motor 12, etc., or the cooling targets of the cooling devices 60A, 60B in FIG. 4.

[0138] When the excavator 100 is provided with the cooling device 60 in FIG. 3, in the above-described cooling determination process P3, the control device 30 determines whether or not the temperature of the cooling target acquired from the temperature sensor 54 satisfies at least one of the following cooling conditions CC1 to CC4.

[0139] CC1: The temperature T1 of the power storage device 19 ≥ temperature Ta CC2: The temperature T2 of the DC-DC converter 44 ≥ temperature Tb CC3: The temperature T3 of the inverter 18 ≥ temperature Tc CC4: The temperature T4 of the motor 12 for the pump ≥ temperature Td

[0140] Here, among the temperatures Ta to Td which are the threshold values of the above cooling conditions CC1 to CC4, the temperature Ta is the lowest, the temperature Tc is higher than the temperature Tb, and the temperature Td is the highest. The temperature Ta is, for example, about 30°C to 35°C. The temperature Tb is, for example, about 70°C to 80°C. The temperature Tc is, for example, about 80°C to 90°C. The temperature Td is, for example, about 100°C to 110°C.

[0141] In this process P3, when the control device 30 determines that, for example, all of the above cooling conditions CC1 to CC4 are not satisfied (NO), the control device 30 repeats the above processes P2 and P3. On the other hand, in this process P3, when the control device 30 determines that, for example, at least one of the above cooling conditions CC1 to CC4 is satisfied (YES), the control device 30 executes the next cooling operation process P4.

[0142] When the excavator 100 is equipped with the cooling device 60 in FIG. 3, in this process P4, the control device 30 operates the water pump 64 (an example of a cooling pump) and the cooling fan 90 of the cooling device 60. As a result, the water pump 64 circulates cooling water (an example of a refrigerant) in the refrigerant circuit 66, and the cooling targets of the cooling device 60 including the power storage device 19, the DC-DC converter 44, the inverter 18, and the motor 12 for the pump are cooled. In addition, the cooling water whose temperature has risen after cooling the cooling targets of the cooling device 60 is forced air-cooled by the air blown by the cooling fan 90 to the radiator 62 in the process of passing through the radiator 62, and the temperature thereof decreases.

[0143] On the other hand, when the excavator 100 is provided with the cooling devices 60A and 60B in FIG. 4, the control device 30 determines whether or not all of the cooling condition CC1 of the power storage device 19 or the cooling conditions CC2 to CC4 of the cooling targets other than the power storage device 19 are satisfied in the above-described cooling determination process P3. In this process P3, when the control device 30 determines that the cooling condition CC1 of the power storage device 19 is satisfied (YES), it executes the next cooling operation process P4. In this process P4, the control device 30 operates the water pump 64B and the cooling fan 90B of the cooling device 60B.

[0144] As a result, in the cooling device 60B of FIG. 4, the water pump 64B circulates the cooling water in the refrigerant circuit 66B, and the power storage device 19 is cooled. Further, the cooling water whose temperature has risen by cooling the power storage device 19 is forced-air cooled and its temperature decreases by heat exchange with the air blown by the cooling fan 90B to the radiator 62B in the process of passing through the radiator 62B.

[0145] Also, in the process P3 when the excavator 100 is provided with the cooling devices 60A and 60B in FIG. 4, when the control device 30 determines that at least one of the cooling conditions CC2 to CC4 of the cooling targets other than the power storage device 19 is satisfied (YES), it executes the next cooling operation process P4. In this process P4, the control device 30 operates the water pump 64A and the cooling fan 90A of the cooling device 60A.

[0146] As a result, in the cooling device 60A of FIG. 4, the water pump 64A circulates the cooling water in the refrigerant circuit 66A, and the DC-DC converter 44, the inverter 18, and the pump motor 12 are cooled. Further, the cooling water whose temperature has risen by cooling these cooling targets is forced-air cooled and its temperature decreases by heat exchange with the air blown by the cooling fan 90A to the radiator 62A in the process of passing through the radiator 62A.

[0147] After the above-described cooling operation process P4, the control device 30 executes, for example, the following cooling stop determination process P5.

[0148] When the excavator 100 is equipped with the cooling device 60 in FIG. 3, in the cooling stop determination process P5, the control device 30, for example, acquires the detection result of the temperature sensor 54 and determines whether all of the following cooling stop conditions SC1 to SC4 are satisfied.

[0149] SC1: The temperature T1 of the power storage device 19 ≤ the temperature Te SC2: The temperature T2 of the DC-DC converter 44 ≤ the temperature Tf SC3: The temperature T3 of the inverter 18 ≤ the temperature Tg SC4: The temperature T4 of the pump motor 12 ≤ the temperature Th

[0150] Here, among the temperatures Te to Th of the thresholds of the cooling stop conditions SC1 to SC4, the temperature Te is the lowest, the temperature Tg is higher than the temperature Tf, and the temperature Th is the highest. The temperature Te is, for example, about 20°C to 25°C. The temperature Tf is, for example, about 50°C to 60°C. The temperature Tg is, for example, about 60°C to 70°C. The temperature Th is, for example, about 80°C to 90°C. That is, the temperatures Te, Tf, Tg, and Th of the thresholds of the cooling stop conditions SC1 to SC4 are set to be about 5°C to 20°C lower than the temperatures Ta, Tb, Tc, and Td of the thresholds of the aforementioned cooling conditions CC1 to CC4, respectively.

[0151] In this process P5, when the control device 30 determines that, for example, at least one of the above cooling stop conditions SC1 to SC4 is not satisfied (NO), the control device 30 repeats the above processes P4 and P5. On the other hand, in this process P5, when the control device 30 determines that, for example, all of the above cooling stop conditions SC1 to SC4 are satisfied (YES), the control device 30 executes the next cooling stop process P6.

[0152] In this process P6, the control device 30 stops the water pump 64 and the cooling fan 90 of the cooling device 60.

[0153] On the other hand, when the excavator 100 is equipped with the cooling devices 60A and 60B in FIG. 4, the control device 30 executes the above processes P5 and P6 for each of the cooling devices 60A and 60B.

[0154] Specifically, in process P5 for the cooling device 60B, the control device 30 determines whether the power storage device 19 satisfies the above cooling stop condition SC1. In this process P5, when the control device 30 determines that the cooling stop condition SC1 is not satisfied (NO), it maintains the operating state of the water pump 64B and the cooling fan 90B of the cooling device 60B, and repeats the above processes P4 and P5.

[0155] As a result, in the cooling device 60B, the water pump 64B circulates cooling water in the refrigerant circuit 66B, and the power storage device 19 is cooled. Also, the cooling water whose temperature has risen after cooling the power storage device 19 is forced-air cooled and its temperature decreases through heat exchange with the air blown by the cooling fan 90B to the radiator 62B in the process of passing through the radiator 62B.

[0156] Also, in this process P5, when the control device 30 determines that the cooling stop condition SC1 is satisfied (YES), in process P6 for the cooling device 60B, it stops the water pump 64B and the cooling fan 90B of the cooling device 60B.

[0157] Furthermore, in process P5 for the cooling device 60A, the control device 30 determines whether the DC-DC converter 44, the inverter 18, and the power storage device 19 all satisfy the above cooling stop conditions SC2 to SC4. In this process P5, when the control device 30 determines that at least one of the cooling stop conditions SC2 to SC4 is not satisfied (NO), it maintains the operating state of the water pump 64A and the cooling fan 90A of the cooling device 60A, and repeats the above processes P4 and P5.

[0158] As a result, in the cooling device 60A, the water pump 64A circulates cooling water in the refrigerant circuit 66A, and the DC-DC converter 44, the inverter 18, and the pump motor 12 are cooled. Also, the cooling water whose temperature has risen after cooling these cooling targets is forced-air cooled and its temperature decreases through heat exchange with the air blown by the cooling fan 90A to the radiator 62A in the process of passing through the radiator 62A.

[0159] Also, in this process P5, when the control device 30 determines that all of the above cooling stop conditions SC2 to SC4 are satisfied (YES), in process P6 for the cooling device 60A, the water pump 64A and the cooling fan 90A of the cooling device 60A are stopped.

[0160] After the completion of the above cooling stop process P6, the control device 30 executes, for example, an end determination process P7. In this process P7, the control device 30 determines whether or not end conditions such as whether the start switch of the excavator 100 has been turned off (for example, the presence or absence of a key OFF operation) are satisfied. In this process P7, when the control device 30 determines that the end conditions are not satisfied (NO), the above processes P2 to P7 are repeated. Also, in this process P7, when the control device 30 determines that the end conditions are satisfied (YES), the process flow shown in FIG. 5 is ended.

[0161] On the other hand, a user who performs maintenance of the excavator 100 including bleeding the air in the above refrigerant circuits 66, 66A, 66B performs the following preparatory work before turning on the start switch of the excavator 100 or operating the input device 52 to start the process flow of FIG. 5. For example, during the production process of the excavator 100, the user injects refrigerant into the radiator 62 of the cooling device 60 in FIG. 3 or the radiators 62A, 62B of the cooling devices 60A, 60B in FIG. 4. Alternatively, for example, after using the excavator 100 for a certain period of time, the user discharges the old refrigerant from the radiator 62 of the cooling device 60 in FIG. 3 or the radiators 62A, 62B of the cooling devices 60A, 60B in FIG. 4 and injects new refrigerant.

[0162] More specifically, when the user of the excavator 100 injects cooling water (an example of a refrigerant) into the radiator 62 of the cooling device 60, the user removes the radiator cap 62c detachably attached to the refrigerant inlet at the upper part of the radiator 62 and injects the cooling water into the refrigerant inlet. Here, the user injects a sufficient amount of cooling water into the radiator 62 while visually checking the water level of the cooling water in the radiator 62, for example, from the refrigerant inlet. These operations are the same for the radiators 62A and 62B of the cooling devices 60A and 60B. After that, the user who performs air bleeding of the refrigerant turns on the start switch of the excavator 100 (for example, performs a key ON operation) or performs a predetermined operation for starting the maintenance mode via the input device 52.

[0163] When the start switch of the excavator 100 is turned on or a predetermined operation is performed via the input device 52, the control device 30 starts the processing flow shown in FIG. 5 and executes the above-described operation reception process P1.

[0164] In this process P1, the user who performs air bleeding of the refrigerant inputs the confirmation of the maintenance mode to the input device 52 as described above. Further, in this process P1, when the control device 30 receives the input of the confirmation of the maintenance mode via the input device 52, it maintains the state in which the pump motor 12 is stopped as described above. Then, the control device 30 executes the above-described mode determination process P2.

[0165] In this process P2, when the control device 30 determines that the selection result of the mode input by the user in the previous process P1 is the confirmation of the maintenance mode (YES), it executes the next cooling pump operation process P8. In this process P8, the control device 30 operates the water pump 64 of the cooling device 60 in FIG. 3 or the water pumps 64A and 64B of the cooling devices 60A and 60B in FIG. 4 with the pump motor 12 stopped.

[0166] As a result, in the cooling device 60, the cooling water injected into the radiator 62 from the refrigerant injection port is pumped by the water pump 64 at the upstream end of the refrigerant circuit 66. The cooling water pumped by the water pump 64 fills the refrigerant circuit 66 and the refrigerant flow path of the object to be cooled while pushing out the air in the refrigerant circuit 66 and the refrigerant flow path of the object to be cooled. In this process, the water level of the cooling water in the radiator 62 drops. Therefore, the user who vents the refrigerant replenishes the cooling water through the refrigerant injection port while visually checking the water level of the cooling water from the refrigerant injection port. This air venting process is the same for the cooling devices 60A and 60B.

[0167] After operating the water pump 64 or the water pumps 64A and 64B with the pump motor 12 stopped in the above-described process P8, the control device 30 executes a maintenance mode end determination process P9. In this process P9, the control device 30, for example, causes a display device constituting the output device 50 to display an image for selecting the end of the maintenance mode, and accepts an input for ending the maintenance mode by the user via the input device 52. Further, in this process P9, if the control device 30 determines that the user has not input the end of the maintenance mode (NO) via the input device 52, for example, the control device 30 executes the next forced air cooling determination process P10.

[0168] In this process P10, the control device 30, similar to the above-described cooling determination process P3, for example, acquires the detection result of the temperature sensor 54 and determines whether or not at least one of the following cooling conditions CC1 to CC2 is satisfied.

[0169] CC1: The temperature T1 of the power storage device 19 ≥ the temperature Ta CC2: The temperature T2 of the DC-DC converter 44 ≥ the temperature Tb

[0170] In this process P10, when the control device 30 determines that, for example, both of the above cooling conditions CC1 to CC2 are not satisfied (NO), the control device 30 repeats the above processes P9 and P10. On the other hand, in this process P10, when the control device 30 determines that, for example, at least one of the above cooling conditions CC1 to CC2 is satisfied (YES), the control device 30 executes the next cooling fan operation process P11.

[0171] In this process P11, the control device 30 operates the cooling fan 90 or the cooling fans 90A and 90B, for example, with the pump motor 12 stopped and the water pump 64 or the water pumps 64A and 64B operating.

[0172] More specifically, when the excavator 100 is equipped with the cooling device 60 in FIG. 3, when the control device 30 determines in the above process P10 that at least one of the cooling conditions CC1 to CC2 is satisfied (YES), the control device 30 operates the cooling fan 90 of the cooling device 60.

[0173] Also, when the excavator 100 is equipped with the cooling devices 60A and 60B in FIG. 4, when the control device 30 determines in the above process P10 that the cooling condition CC1 of the power storage device 19 is satisfied, the control device 30 operates the cooling fan 90B of the cooling device 60B. Further, when the control device 30 determines in the above process P10 that the cooling condition CC2 of the DC-DC converter 44 is satisfied, the control device 30 operates the cooling fan 90A of the cooling device 60A.

[0174] As a result, in the cooling device 60 or the cooling devices 60A and 60B, with the operation of the pump motor 12 and the inverter 18 stopped, the water pumps 64, 64A, or 64B circulate cooling water in the refrigerant circuits 66, 66A, or 66B. As a result, the power storage device 19 and / or the DC-DC converter 44, which have had their temperature increased by supplying power to the water pumps 64, 64A, or 64B, are cooled. Also, the cooling water, which has had its temperature increased by cooling the power storage device 19 and / or the DC-DC converter 44, is forced-air cooled and its temperature decreases through heat exchange with the air blown by the cooling fans 90, 90A, or 90B as it passes through the radiators 62, 62A, or 62B.

[0175] Next, the control device 30 executes maintenance mode end determination processing P12 similar to the above-described processing P9. In this processing P12, the control device 30 causes, for example, a display device constituting the output device 50 to display an image for selecting the end of the maintenance mode, and accepts an input for ending the maintenance mode from the user via the input device 52. Further, in this processing P12, when the control device 30 determines that the user has not input the end of the maintenance mode (NO) via the input device 52, for example, it executes the following forced air cooling stop determination processing P13.

[0176] When the excavator 100 is provided with the cooling device 60 shown in FIG. 3, in this processing P13, the control device 30 determines whether the power storage device 19 and the DC-DC converter 44 satisfy the above-described cooling stop conditions SC1 and SC2 in the same manner as in the above-described processing P5.

[0177] SC1: The temperature T1 of the power storage device 19 ≤ the temperature Te SC2: The temperature T2 of the DC-DC converter 44 ≤ the temperature Tf

[0178] In this processing P13, when the control device 30 determines that at least one of the above cooling stop conditions SC1 or SC2 is not satisfied (NO), it maintains the state in which the water pump 64 and the cooling fan 90 of the cooling device 60 are operating. Then, the control device 30 repeats the above-described processing P12 and P13. Also, in this processing P13, when the control device 30 determines that the above cooling stop conditions SC1 and SC2 are satisfied (YES), it executes the next cooling fan stop processing P14. In this processing P14, the control device 30 maintains the state in which the water pump 64 of the cooling device 60 is operating and stops the cooling fan 90.

[0179] On the other hand, when the excavator 100 is provided with the cooling devices 60A and 60B shown in FIG. 4, the control device 30 executes the above-described processing P13 and P14 for each of the cooling devices 60A and 60B.

[0180] Specifically, in process P13 for the cooling device 60B, the control device 30 determines whether the power storage device 19 satisfies the above cooling stop condition SC1. In this process P13, when the control device 30 determines that the cooling stop condition SC1 is not satisfied (NO), it maintains the operating state of the water pump 64B and the cooling fan 90B of the cooling device 60B and repeats the above processes P12 and P13.

[0181] As a result, in the cooling device 60B, the water pump 64B circulates cooling water in the refrigerant circuit 66B to purge air from the refrigerant circuit 66B, and the power storage device 19 is cooled. In addition, the cooling water that has cooled the power storage device 19 and whose temperature has risen is forced-air cooled and its temperature drops through heat exchange with the air blown by the cooling fan 90B to the radiator 62B in the process of passing through the radiator 62B.

[0182] Also, in this process P13, when the control device 30 determines that the cooling stop condition SC1 is satisfied (YES), in process P14 for the cooling device 60B, it maintains the operating state of the water pump 64B of the cooling device 60B and stops the cooling fan 90B. As a result, in the cooling device 60B, the water pump 64B circulates cooling water in the refrigerant circuit 66B to purge air from the refrigerant circuit 66B.

[0183] Also, in process P13 for the cooling device 60A, the control device 30 determines whether the DC-DC converter 44 satisfies the above cooling stop condition SC2. In this process P13, when the control device 30 determines that the cooling stop condition SC2 is not satisfied (NO), it maintains the operating state of the water pump 64A and the cooling fan 90A of the cooling device 60A and repeats the above processes P12 and P13.

[0184] As a result, in the cooling device 60A, the water pump 64A circulates cooling water in the refrigerant circuit 66A to perform air bleeding, and at the same time, the DC-DC converter 44, the inverter 18, and the pump motor 12 are cooled. Further, the cooling water whose temperature has risen by cooling these cooling targets is forced-air cooled by heat exchange with the air blown by the cooling fan 90A to the radiator 62A as it passes through the radiator 62A, and the temperature decreases.

[0185] Also, in this process P13, when the control device 30 determines that the above cooling stop condition SC2 is satisfied (YES), in the process P14 for the cooling device 60A, the control device 30 maintains the state in which the water pump 64A of the cooling device 60A is operating and stops the cooling fan 90A. As a result, in the cooling device 60A, the water pump 64A circulates cooling water in the refrigerant circuit 66A to progress the air bleeding of the refrigerant circuit 66A.

[0186] After the end of the above cooling fan stop process P14, the control device 30 executes the above processes P9 and below again.

[0187] The user who performs air bleeding of the refrigerant of the cooling device 60 in FIG. 3 can recognize that the air bleeding of the refrigerant is completed, for example, by the water level in the radiator 62 visually confirmed from the refrigerant inlet becoming constant without decreasing. The same applies to the cooling devices 60A and 60B in FIG. 4. When the user recognizes that the air bleeding of the refrigerant is completed, in the above maintenance mode end determination processes P9 and P12, the user inputs the end of the maintenance mode to the input device 52.

[0188] Then, the control device 30 determines that the maintenance mode has ended (YES) in these processes P9 and P12, and executes the next operation stop process P15. In this process P15, the control device 30 stops the operation of the water pump 64 and the cooling fan 90 of the cooling device 60 in FIG. 3. Similarly, the control device 30 stops the operation of the water pumps 64A and 64B and the cooling fans 90A and 90B of the cooling devices 60A and 60B in FIG. 4. After that, the control device 30 executes the above mode determination process P2.

[0189] In the above processing P3 to P6 in the normal mode, an example in which the water pumps 64, 64A, 64B and the cooling fans 90, 90A, 90B of the respective cooling devices 60, 60A, 60B are simultaneously operated or simultaneously stopped has been described. However, the water pumps 64, 64A, 64B and the cooling fans 90, 90A, 90B may be individually operated or stopped under different conditions.

[0190] FIG. 6 is a flowchart showing another example from the cooling determination process P3 to the cooling stop process P6 of FIG. 5. Hereinafter, an example in the case where the excavator 100 includes the cooling device 60 of FIG. 3 will be described. However, it goes without saying that the following example is applicable when the excavator 100 includes the cooling devices 60A, 60B of FIG. 4.

[0191] When the control device 30 determines, for example, in the above-described mode determination process P2 that it is not in the maintenance mode (NO), that is, it is in the normal mode, the water cooling determination process P31 shown in FIG. 6 is executed. In this process P31, the control device 30 acquires, for example, the detection result of the temperature sensor 54, and determines whether or not at least one of the following water cooling conditions WCC1 to WCC4 is satisfied.

[0192] WCC1: The temperature T1 of the power storage device 19 ≧ the temperature Ta1 WCC2: The temperature T2 of the DC-DC converter 44 ≧ the temperature Tb1 WCC3: The temperature T3 of the inverter 18 ≧ the temperature Tc1 WCC4: The temperature T4 of the pump motor 12 ≧ the temperature Td1

[0193] Here, among the threshold temperatures Ta1 to Td1 of the water cooling conditions WCC1 to WCC4, the temperature Ta1 is the lowest, the temperature Tc1 is higher than the temperature Tb1, and the temperature Td1 is the highest. The temperature Ta1 is, for example, about 30°C. The temperature Tb1 is, for example, about 70°C. The temperature Tc1 is, for example, about 80°C. The temperature Td1 is, for example, about 100°C.

[0194] In this process P31, for example, when the control device 30 determines that all of the above water cooling conditions WCC1 to WCC4 are not satisfied (NO), the above processes P2 and P31 are repeated. On the other hand, in this process P31, for example, when the control device 30 determines that at least one of the above water cooling conditions WCC1 to WCC4 is satisfied (YES), the next water cooling process P41 is executed.

[0195] In this process P41, for example, the control device 30 operates the water pump 64 with the cooling fan 90 of the cooling device 60 in FIG. 3 stopped. Thereby, the water pump 64 circulates the cooling water in the refrigerant circuit 66 to cool the cooling targets of the cooling device 60 including the power storage device 19, the DC-DC converter 44, the inverter 18, and the pump motor 12. Further, the cooling water whose temperature has risen after cooling the cooling targets of the cooling device 60 is cooled by heat exchange with the air around the radiator 62 in the process of passing through the radiator 62.

[0196] Next, the control device 30 executes a forced air cooling determination process P32. In this process P32, for example, the control device 30 acquires the detection result of the temperature sensor 54 and determines whether at least one of the following forced air cooling conditions ACC1 to ACC4 is satisfied.

[0197] ACC1: The temperature T1 of the power storage device 19 ≥ temperature Ta2 ACC2: The temperature T2 of the DC-DC converter 44 ≥ temperature Tb2 ACC3: The temperature T3 of the inverter 18 ≥ temperature Tc2 ACC4: The temperature T4 of the pump motor 12 ≥ temperature Td2

[0198] Here, among the temperatures Ta2 to Td2 which are the thresholds of the above-mentioned forced air cooling conditions ACC1 to ACC4, the temperature Ta2 is the lowest, the temperature Tc2 is higher than the temperature Tb2, and the temperature Td2 is the highest. The temperature Ta2 is, for example, about 35°C. The temperature Tb2 is, for example, about 80°C. The temperature Tc2 is, for example, about 90°C. The temperature Td2 is, for example, about 110°C. That is, the temperatures Ta2 to Td2 which are the thresholds of the forced air cooling conditions ACC1 to ACC4 are set higher than the temperatures Ta1 to Td1 which are the thresholds of the water cooling conditions WCC1 to WCC4.

[0199] In this process P32, for example, when the control device 30 determines that all of the above-mentioned forced air cooling conditions ACC1 to ACC4 are not satisfied (NO), the control device 30 repeats this determination process P32 until at least one condition is satisfied. On the other hand, in this process P32, for example, when the control device 30 determines that at least one of the above-mentioned forced air cooling conditions ACC1 to ACC4 is satisfied (YES), the control device 30 executes the next forced air cooling process P42.

[0200] In this process P42, for example, the control device 30 operates the cooling fan 90 in a state where the water pump 64 of the cooling device 60 in FIG. 3 is operated. As a result, the water pump 64 circulates the cooling water in the refrigerant circuit 66, and the cooling targets of the cooling device 60 including the power storage device 19, the DC-DC converter 44, the inverter 18, and the pump motor 12 are cooled. Further, the cooling water whose temperature has risen by cooling the cooling targets of the cooling device 60 is forced air-cooled by the air blown by the cooling fan 90 toward the radiator 62 in the process of passing through the radiator 62, and the temperature thereof decreases.

[0201] Next, the control device 30 executes a forced air cooling stop determination process P51. In this process P51, for example, the control device 30 acquires the detection result of the temperature sensor 54, and determines whether or not all of the following forced air cooling stop conditions ASC1 to ASC4 are satisfied.

[0202] ASC1: The temperature T1 of the power storage device 19 ≤ the temperature Te2 ASC2: The temperature T2 of the DC-DC converter 44 ≤ the temperature Tf2 ASC3: Temperature T3 of the inverter 18 ≤ Temperature Tg2 ASC4: Temperature T4 of the pump motor 12 ≤ Temperature Th2

[0203] Here, among the temperatures Te2 to Th2 of the thresholds of the above forced air cooling stop conditions ASC1 to ASC4, the temperature Te2 is the lowest, the temperature Tg2 is higher than the temperature Tf2, and the temperature Th2 is the highest. The temperature Te2 is, for example, about 25°C. The temperature Tf2 is, for example, about 60°C. The temperature Tg2 is, for example, about 70°C. The temperature Th2 is, for example, about 90°C. That is, the temperatures Te2, Tf2, Tg2, and Th2 of the thresholds of the above forced air cooling stop conditions ASC1 to ASC4 are set to be about 10°C to 20°C lower than the temperatures Ta2, Tb2, Tc2, and Td2 of the thresholds of the above forced air cooling conditions ACC1 to ACC4, respectively.

[0204] In this process P51, when the control device 30 determines that, for example, at least one of the above forced air cooling stop conditions ASC1 to ASC4 is not satisfied (NO), this determination process P51 is repeated until all conditions are satisfied. On the other hand, in this process P51, when the control device 30 determines that, for example, all of the above forced air cooling stop conditions ASC1 to ASC4 are satisfied (YES), the next forced air cooling stop process P61 is executed.

[0205] In this process P61, the control device 30 stops the cooling fan 90 while operating the water pump 64 of the cooling device 60.

[0206] Next, the control device 30 executes a water cooling stop determination process P52. In this process P52, the control device 30, for example, acquires the detection result of the temperature sensor 54 and determines whether all of the following water cooling stop conditions WSC1 to WSC4 are satisfied.

[0207] WSC1: Temperature T1 of the power storage device 19 ≤ Temperature Te1 WSC2: Temperature T2 of the DC - DC converter 44 ≤ Temperature Tf1 WSC3: Temperature T3 of the inverter 18 ≤ Temperature Tg1 WSC4: Temperature T4 of the motor 12 for the pump ≤ Temperature Th1

[0208] Here, among the temperatures Te1 to Th1 of the thresholds of the above water cooling stop conditions WSC1 to WSC4, the temperature Te1 is the lowest, the temperature Tg1 is higher than the temperature Tf1, and the temperature Th1 is the highest. The temperature Te1 is, for example, about 20°C. The temperature Tf1 is, for example, about 50°C. The temperature Tg1 is, for example, about 60°C. The temperature Th1 is, for example, about 80°C. That is, the temperatures Te1, Tf1, Tg1, and Th1 of the thresholds of the above water cooling stop conditions WSC1 to WSC4 are set to be about 5°C to 10°C lower than the temperatures Te2, Tf2, Tg2, and Th2 of the thresholds of the above forced air cooling stop conditions ASC1 to ASC4, respectively.

[0209] In this process P52, when the control device 30 determines that, for example, at least one of the above water cooling stop conditions WSC1 to WSC4 is not satisfied (NO), the control device 30 repeats the above processes P32 to P52. On the other hand, in this process P52, when the control device 30 determines that, for example, all of the above water cooling stop conditions WSC1 to WSC4 are satisfied (YES), the control device 30 executes the next water cooling stop process P62.

[0210] In this process P62, the control device 30 stops the water pump 64 with the cooling fan 90 of the cooling device 60 stopped. After that, the control device 30 executes the above end determination process P7.

[0211] Hereinafter, based on the comparison with the conventional work vehicle, the operation of the excavator 100 of the above-described present embodiment will be described.

[0212] Conventionally, a work vehicle includes a refrigerant circuit that circulates a refrigerant such as cooling water to cool a cooling target including an internal combustion engine or an electric motor as a prime mover for driving a hydraulic pump. After injecting the refrigerant during the manufacture of the work vehicle or after injecting the refrigerant during the replacement of the refrigerant after using the work vehicle for a predetermined period, it is necessary to bleed air from the refrigerant circuit. For example, in the conventional work vehicle described in Patent Document 1 above, after starting the engine, until the engine cooling water reaches a predetermined temperature, the air in the branch path cannot be pushed out, and the energy consumption during air bleeding increases. Further, in order to increase the supply pressure of the engine cooling water by the water pump, it is necessary to increase the rotational speed of the engine, so the energy consumption during air bleeding further increases.

[0213] On the other hand, the excavator 100 of the present embodiment includes a lower traveling body 1, an upper swing body 3 that is swingably mounted on the lower traveling body 1, and traveling hydraulic motors 1A, 1B and a swing hydraulic motor 2A (an example of a hydraulic actuator) that drive a driven part including the lower traveling body 1 and the upper swing body 3. Further, the excavator 100 includes a main pump 14 (an example of a hydraulic pump) that supplies hydraulic oil to the traveling hydraulic motors 1A, 1B and the swing hydraulic motor 2A, and a pump electric motor 12 (an example of a prime mover) that drives the main pump 14. Furthermore, the excavator 100 includes a refrigerant circuit 66 through which cooling water (an example of a refrigerant) that cools a cooling target including the pump electric motor 12 flows, a water pump 64 (an example of a refrigerant pump) that circulates the cooling water through the refrigerant circuit 66, and a control device 30 that controls the operations of the pump electric motor 12 and the water pump 64. The control device 30 is configured to be able to switch between a normal mode in which the water pump 64 is operated with the pump electric motor 12 operating and a maintenance mode in which the water pump 64 is operated with the pump electric motor 12 stopped.

[0214] With such a configuration, according to the excavator 100 of the present embodiment, when the user performs maintenance on the excavator 100 for bleeding the refrigerant circuit 66, the control device 30 can select a maintenance mode. As a result, without operating the pump motor 12 as a prime mover for driving the main pump 14 which is a hydraulic pump, the water pump 64 as a refrigerant pump for circulating a refrigerant such as cooling water in the refrigerant circuit 66 can be operated. Consequently, compared with the case of bleeding air with the pump motor 12 operated to drive the main pump 14, the energy consumption can be significantly reduced.

[0215] Also, in the excavator 100 of the present embodiment, the pump motor 12 as a prime mover is an electric motor, and the water pumps 64, 64A, 64B as refrigerant pumps are electric pumps.

[0216] With such a configuration, the excavator 100 of the present embodiment can not only reduce the temperature of the refrigerant such as cooling water circulating in the refrigerant circuit 66 compared with the case where the prime mover is an internal combustion engine, but also reduce the environmental load due to exhaust gas and the like. Further, when a hydraulic pump is used as the refrigerant pump, it is necessary to operate the prime mover for driving the refrigerant pump. In contrast, by using the water pumps 64, 64A, 64B as electric pumps as the refrigerant pumps, the pump motor 12 as the prime mover and the water pumps 64, 64A, 64B as the refrigerant pumps can be operated independently.

[0217] Further, the control device 30 of the excavator 100 of the present embodiment operates the water pumps 64, 64A, 64B as refrigerant pumps in the normal mode when the temperatures T1, T2, T3, T4 of cooling targets such as the power storage device 19, the DC - DC converter 44, the inverter 18, and the pump motor 12 are equal to or exceed the temperatures Ta1, Tb1, Tc1, Td1, etc. as the first threshold values. Also, the control device 30 operates the water pumps 64, 64A, 64B as refrigerant pumps in the maintenance mode regardless of the temperature of the cooling targets.

[0218] With such a configuration, in the normal mode, when the temperature of the components to be cooled including the pump motor 12 reaches or exceeds the temperatures Ta1, Tb1, Tc1, Td1 as the first thresholds, the water pump 64 is driven. Therefore, in the normal mode, even if the user tries to operate the water pump 64, there may be a time lag before the water pump 64 actually operates. However, in the excavator 100 of the present embodiment, when the user switches the mode to the maintenance mode via the control device 30, the water pump 64 can be immediately operated regardless of the temperature of the components to be cooled. Therefore, according to the excavator 100 of the present embodiment, it is possible to shorten the working time during air bleeding.

[0219] Further, the excavator 100 of the present embodiment further includes radiators 62, 62A, 62B provided in the refrigerant circuit 66 for cooling a refrigerant such as cooling water, and cooling fans 90, 90A, 90B whose operations are controlled by the control device 30 for cooling the radiators 62, 62A, 62B. In the normal mode, when the temperature of the components to be cooled including the pump motor 12 is equal to or higher than the temperatures Ta2, Tb2, Tc2, Td2 as the second thresholds, which are higher than the temperatures Ta1, Tb1, Tc1, Td1 as the first thresholds, the control device 30 operates the cooling fans 90, 90A, 90B.

[0220] With such a configuration, as shown in FIG. 6, in the excavator 100 of the present embodiment, when the temperature of the components to be cooled such as the pump motor 12 rises in the normal mode, the water pumps 64, 64A, 64B can be operated prior to the cooling fans 90, 90A, 90B. Further, when the temperature of the components to be cooled such as the pump motor 12 further rises in the normal mode, in addition to the water pumps 64, 64A, 64B, the cooling fans 90, 90A, 90B can be operated. Therefore, it is possible to efficiently cool the components to be cooled such as the pump motor 12 according to the temperature.

[0221] In addition, the excavator 100 of the present embodiment further includes a power storage device 19 that supplies power to the pump motor 12 as a prime mover, water pumps 64, 64A, 64B as refrigerant pumps, and cooling fans 90, 90A, 90B. Further, the excavator 100 of the present embodiment further includes a DC-DC converter 44 that steps down the power of the power storage device 19 and supplies it to the water pumps 64, 64A, 64B and the cooling fans 90, 90A, 90B. Further, the excavator 100 of the present embodiment further includes an inverter 18 that converts the DC power of the power storage device 19 into AC power and supplies it to the pump motor 12 as a prime mover. And the cooling targets include the power storage device 19, the pump motor 12, the inverter 18, and the DC-DC converter 44.

[0222] With such a configuration, the excavator 100 of the present embodiment can efficiently cool high-voltage devices including the power storage device 19, the pump motor 12, the inverter 18, and the DC-DC converter 44 by heat exchange with a refrigerant such as cooling water circulating in the refrigerant circuits 66, 66A. Further, in the maintenance mode, since the pump motor 12 is not operated and the pump motor 12 and the inverter 18 do not generate heat, the temperature of the refrigerant such as cooling water circulating in the refrigerant circuits 66, 66A can be lowered.

[0223] In addition, the excavator 100 of the present embodiment may include, for example, cooling devices 60A and 60B shown in FIG. 4. That is, the refrigerant circuit may include a refrigerant circuit 66A as a first refrigerant circuit that cools the pump motor 12 as a prime mover, the inverter 18, and the DC-DC converter 44, and a refrigerant circuit 66B as a second refrigerant circuit that cools the power storage device 19. Further, the refrigerant pump may include a water pump 64A as a first refrigerant pump provided in the refrigerant circuit 66A and a 64B as a second refrigerant pump provided in the refrigerant circuit 66B. Further, the radiator may include a radiator 62A as a first radiator provided in the refrigerant circuit 66A and a radiator 62B as a second radiator provided in the refrigerant circuit 66B. Further, the cooling fan may include a cooling fan 90A as a first cooling fan that cools the radiator 62A and a cooling fan 90B as a second cooling fan that cools the radiator 62B.

[0224] With such a configuration, the excavator 100 of the present embodiment can cool the power storage device 19 with a refrigerant circuit 66B separate from the refrigerant circuit 66A that cools high-temperature and high-voltage devices including the DC-DC converter 44, the inverter 18, and the pump motor 12, which become hotter than the power storage device 19. Thereby, in the normal mode, compared with the case where the power storage device 19 and the high-temperature and high-voltage devices are cooled by a common refrigerant circuit 66, the power storage device 19 can be maintained at a low temperature, the operating frequency of the cooling fans 90A and 90B can be reduced, and the energy consumption can be reduced.

[0225] In addition, the control device 30 of the excavator 100 of the present embodiment operates the cooling fans 90, 90A, and 90B in the maintenance mode when the temperature of the DC-DC converter 44 or the power storage device 19 is equal to or exceeds the temperatures Ta2 and Tb2 as the third threshold values.

[0226] In the excavator 100 of the present embodiment, in the maintenance mode, by supplying power from the power storage device 19 to the water pumps 64, 64A, 64B via the DC-DC converter 44, the temperatures of the power storage device 19 and the DC-DC converter 44 increase. However, with the above-described configuration, when the temperatures of the power storage device 19 and the DC-DC converter 44 reach or exceed the temperatures Ta2 and Tb2, respectively, the cooling fans 90, 90A, 90B operate. As a result, the cooling fans 90, 90A, 90B are forced-air cooled by heat exchange with the air blown toward the radiators 62, 62A, 62B, and the temperature of the cooling water decreases. Therefore, in the maintenance mode, the power storage device 19 and the DC-DC converter 44 can be efficiently cooled by heat exchange with the cooling water.

[0227] As described above, according to the present embodiment, it is possible to provide an excavator 100 capable of reducing the energy consumption during maintenance including bleeding the refrigerant circuits 66, 66A, 66B through which the refrigerant for cooling the pump motor 12 serving as the prime mover for driving the main pump 14, which is a hydraulic pump, circulates.

[0228] As described above, the preferred embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments. Various modifications or substitutions can be applied to the above-described embodiments without departing from the scope of the present invention. Also, the features described separately can be combined as long as no technical contradiction occurs.

[0229] For example, the excavator according to the present disclosure may include an internal combustion engine as a prime mover. In this case, an electric pump that operates independently of the internal combustion engine can be employed as the refrigerant pump.

Description of Reference Numerals

[0230] 1 Lower Travel Body (Driven Portion) 1A Travel Hydraulic Motor (Hydraulic Actuator) 1B Travel Hydraulic Motor (Hydraulic Actuator) 2A Swing Hydraulic Motor (Hydraulic Actuator) 3 Upper Swivel Body (Driven Part) 12 Pump Motor (Prime Mover, Object to be Cooled, Electric Motor) 14 Main Pump (Hydraulic Pump) 18 Inverter (Object to be Cooled) 19 Energy Storage Device (Object to be Cooled) 30 Control Device 44 DC-DC Converter (Converter, Object to be Cooled) 62 Radiator 62A Radiator (First Radiator) 62B Radiator (Second Radiator) 64 Water Pump (Refrigerant Pump, Electric Pump) 64A Water Pump (Refrigerant Pump, Electric Pump, First Refrigerant Pump) 64B Water Pump (Refrigerant Pump, Electric Pump, Second Refrigerant Pump) 66 Refrigerant Circuit 66A Refrigerant Circuit (First Cooling Circuit) 66B Refrigerant Circuit (Second Cooling Circuit) 90 Cooling Fan 90A Cooling Fan (First Cooling Fan) 90B Cooling Fan (Second Cooling Fan) 100 Excavator Ta1 Temperature (First Threshold Value) Tb1 Temperature (First Threshold Value) Tc1 Temperature (First Threshold Value) Td1 Temperature (First Threshold Value) Ta2 Temperature (Second Threshold Value, Third Threshold Value) Tb2 Temperature (Second Threshold Value, Third Threshold Value) Tc2 Temperature (Second Threshold Value) Td2 Temperature (Second Threshold Value)

Claims

1. A lower traveling body, an upper swing body rotatably mounted on the lower traveling body, a hydraulic actuator for driving a driven part including the lower traveling body and the upper swing body, a hydraulic pump for supplying hydraulic oil to the hydraulic actuator, a prime mover for driving the hydraulic pump, a refrigerant circuit through which a refrigerant for cooling a cooling target including the prime mover flows, a refrigerant pump for circulating the refrigerant through the refrigerant circuit, and a control device for controlling the operation of the prime mover and the refrigerant pump, wherein the control device has a normal mode in which the refrigerant pump is operated with the prime mover operating, and a maintenance mode in which the refrigerant pump is operated with the prime mover stopped, and is configured to be switchable between them, a hydraulic excavator.

2. The prime mover is an electric motor, and the refrigerant pump is an electric pump, the hydraulic excavator according to Claim 1.

3. The control device operates the refrigerant pump when the temperature of the cooling target exceeds a first threshold value in the normal mode, and operates the refrigerant pump regardless of the temperature of the cooling target in the maintenance mode, the hydraulic excavator according to Claim 2.

4. a radiator provided in the refrigerant circuit for cooling the refrigerant, and a cooling fan whose operation is controlled by the control device for cooling the radiator, further comprising, wherein the control device operates the cooling fan when the temperature of the cooling target exceeds a second threshold value higher than the first threshold value in the normal mode, the hydraulic excavator according to Claim 3.

5. a power storage device for supplying power to the prime mover, the refrigerant pump, and the cooling fan, a converter for stepping down the power of the power storage device and supplying it to the refrigerant pump and the cooling fan, and an inverter for converting the DC power of the power storage device into AC power and supplying it to the prime mover, further comprising, wherein the cooling target includes the power storage device, the prime mover, the inverter, and the converter, the hydraulic excavator according to Claim 4.

6. The refrigerant circuit includes a first refrigerant circuit for cooling the prime mover, the inverter, and the converter, and a second refrigerant circuit for cooling the power storage device, the refrigerant pump includes a first refrigerant pump provided in the first refrigerant circuit and a second refrigerant pump provided in the second refrigerant circuit, and the radiator includes a first radiator provided in the first refrigerant circuit and a second radiator provided in the second refrigerant circuit, The cooling fan includes a first cooling fan that cools the first radiator and a second cooling fan that cools the second radiator. The excavator according to claim 5.

7. In the maintenance mode, when the temperature of the converter or the power storage device exceeds a third threshold value, the control device operates the cooling fan. The excavator according to claim 5.

Images