electric excavator

Abstract

To provide an electric shovel suppressed in lowering of work efficiency.SOLUTION: An electric shovel related to one embodiment of the present disclosure has a battery, an electric motor driven by power supplied from the battery, and a hydraulic drive system for driving a work attachment by the power by the electric motor. When an external power source is chargeably connected to the battery, the electric motor is driven by the power supplied from the external power source to warm up the hydraulic drive system.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an electric shovel.

Background Art

[0002] Conventionally, when the temperature is low, the temperature of the hydraulic oil used in the hydraulic drive system of a shovel also decreases. When working in such a situation, the working efficiency decreases, so a technique for performing a warm-up operation of the hydraulic drive system has been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, in the technique described in Patent Document 1, a technique has been proposed in which a battery is charged and discharged using the power of an engine to warm up the battery, and the warm-up of the hydraulic oil is performed by increasing the discharge pressure of the hydraulic oil in a partial configuration of the hydraulic drive system.

[0005] However, usually, an electric shovel does not have an engine. In such an electric shovel, if the warm-up of the hydraulic drive system consumes the power of the battery, the time that the battery can be used for work becomes short, and the working efficiency may decrease.

[0006] Therefore, in view of the above problems, an object is to provide a technique for suppressing a decrease in working efficiency by warming up a hydraulic drive system with electric power supplied from an external power source.

Means for Solving the Problems

[0007] To achieve the above objective, an electric excavator according to one embodiment of the present disclosure includes a battery, an electric motor powered by electricity supplied from the battery, and a hydraulic drive system that drives a work attachment with power from the electric motor, wherein when an external power source is connected to the battery in a rechargeable manner, the electric excavator has power supplied from the external power source. So, oil The system is configured to warm up the pressure drive system. The system stores time information in a memory unit, calculates a warm-up time based on the amount of power supplied to the motor, the ambient temperature detected by the first detection unit, and the temperature of the hydraulic fluid detected by the second detection unit, and completes battery charging by the time indicated by the time information. At the time obtained by subtracting the warm-up time from the time indicated by the time information, it starts control to operate the motor with power supplied from an external power source to warm up the hydraulic drive system, and completes the warm-up of the hydraulic drive system by the time indicated by the time information when the temperature of the hydraulic fluid contained in the hydraulic drive system reaches or exceeds a predetermined value. [Effects of the Invention]

[0008] According to the above embodiment, by warming up the hydraulic drive system with power supplied from an external power source, the need to warm up using power supplied from the battery can be suppressed, thereby preventing a reduction in the working time using the battery and thus preventing a decrease in work efficiency. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a side view showing a shovel (excavator) according to an embodiment. [Figure 2] Figure 2 is a schematic block diagram showing an example of the configuration of an excavator according to this embodiment. [Figure 3] Figure 3 is a schematic diagram of the hydraulic circuit installed in the excavator according to this embodiment. [Figure 4] Figure 4 is a diagram illustrating the warm-up time information stored in the warm-up time retention unit according to the embodiment. [Figure 5] Figure 5 is a flowchart showing the charging and warm-up procedures performed before the start of work in the excavator controller according to the embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below with reference to the drawings. Furthermore, the embodiments described below are illustrative and not limiting to the invention, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. In addition, identical or corresponding components in each drawing are denoted by the same or corresponding reference numerals, and their descriptions may be omitted.

[0011] [Shovel Overview] First, referring to Figure 1, we will explain the overview of Shovel 200 as an example of an electric excavator.

[0012] The shovel 200 according to this embodiment comprises a lower traveling body 1, an upper rotating body 3 mounted on the lower traveling body 1 so as to be rotatable via a slewing mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments, and a cabin 10.

[0013] The lower traveling body 1 includes, for example, a pair of left and right crawlers, and each crawler is hydraulically driven by a travel hydraulic motor 1R, 1L (see Figure 2), allowing it to move under its own power.

[0014] The upper rotating body 3 rotates relative to the lower traveling body 1 by being hydraulically driven by a rotating hydraulic motor 2M (see Figure 2) via a rotating mechanism 2. All driven elements (e.g., the rotating hydraulic motor 2M) are hydraulically driven by the hydraulic fluid supplied from the main pump 14 (see Figure 2). This is equivalent to a configuration in which the power source (engine) of a so-called hydraulic excavator is replaced with an electric pump 12.

[0015] Further, the upper swing body 3 may be electrically driven by a swing electric motor that is driven by electric power supplied from the battery module 19 through the swing mechanism 2 instead of the swing hydraulic motor 2M. In this case, for example, the excavator 200 is connected to the swing electric motor from the battery module 19 via the power conversion device 100 and the inverter. Then, the swing electric motor may perform a power running operation for swing-driving the upper swing body 3 and a regenerative operation for generating regenerative power to swing-brake the upper swing body 3 under the control of the excavator controller 30 and the inverter. Further, the swing electric motor may supply the regenerative power to the battery module 19 or the pump electric motor 12 via the inverter.

[0016] The boom 4 is attached to the front center of the upper swing body 3 so as to be able to pitch. An arm 5 is attached to the tip of the boom 4 so as to be able to rotate vertically, and a bucket 6 is attached to the tip of the arm 5 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.

[0017] The bucket 6 is an example of a work attachment, and another work attachment may be attached to the tip of the arm 5 instead of the bucket 6 according to the work content or the like. The other end attachment may be, for example, a bucket of a different type from the bucket 6 such as a slope bucket or a dredging bucket. Further, the other work attachment may be, for example, an end attachment of a different type from the bucket such as a breaker, a stirrer, or a grapple.

[0018] The cab 10 is mounted on the front left side of the upper swing body 3, and inside it (the interior), there are provided a driver's seat on which an operator sits and an operation device 26 (see FIG. 2) described later.

[0019] The excavator 200 operates driven elements such as the lower traveling body 1 (left and right crawlers), the upper swing body 3, the boom 4, the arm 5, and the bucket 6 according to the operation of an operator boarding the cab 10.

[0020] Alternatively, instead of being configured to be operable by an operator boarding the cab 10, or in addition thereto, the excavator 200 may be configured to be remotely operated from outside the excavator 200. When the excavator 200 is remotely operated, the interior of the cab 10 may be unmanned. Hereinafter, the description will proceed on the premise that the operation by the operator includes at least one of the operation on the operation device 26 of the operator in the cab 10 and the remote operation by an external operator.

[0021] The remote operation includes, for example, a mode in which the excavator 200 is operated by an operation input regarding an actuator of the excavator 200 performed by a predetermined external device. In this case, the excavator 200 is equipped with a communication device 91 (see FIG. 2) capable of communicating with a predetermined external device, and may transmit, for example, image information (captured image) output by an imaging device (not shown) to the external device. Then, the external device may display the image information (captured image) received on a display device provided in the self-device (hereinafter, “remote operation display device”). Also, various information images (information screens) displayed on the output device 50 (display device) inside the cab 10 of the excavator 200 may similarly be displayed on the remote operation display device of the external device. Thereby, an operator of the external device can remotely operate the excavator 200 while checking display contents such as a captured image or an information screen showing the state around the excavator 200 displayed on the remote operation display device. Then, the excavator 200 operates the hydraulic actuator according to a remote operation signal received from the external device by the communication device 91 (see FIG. 2) and representing the content of the remote operation, and drives driven elements such as the lower traveling body 1 (left and right crawlers), the upper swing body 3, the boom 4, the arm 5, and the bucket 6.

[0022] Furthermore, remote operation may include, for example, a mode in which the shovel 200 is operated by external voice input or gesture input from people (e.g., workers) in the vicinity of the shovel 200. Specifically, the shovel 200 recognizes voices spoken by surrounding workers or gestures made by workers through a voice input device (e.g., microphone) or gesture input device (e.g., imaging device) mounted on the shovel 200 (itself). The shovel 200 may then operate actuators according to the content of the recognized voices or gestures to drive driven elements such as the lower traveling body 1 (left and right crawlers), the upper slewing body 3, the boom 4, the arm 5, and the bucket 6.

[0023] Furthermore, the shovel 200 may operate its actuators automatically, regardless of the operator's actions. This enables the shovel 200 to automatically operate at least some of its driven elements, such as the lower traveling body 1 (crawler 1CL, 1CR), upper slewing body 3, boom 4, arm 5, and bucket 6 (a so-called "automatic driving function" or "machine control function").

[0024] The automatic driving function may include a function that automatically operates driven elements (actuators) other than the target driven element (hydraulic actuator) in response to the operator's operation device 26 or remote operation (a so-called "semi-automatic driving function"). The automatic driving function may also include a function that automatically operates at least some of the multiple driven elements (actuators) on the premise that there is no operator operation device 26 or remote operation (a so-called "fully automatic driving function"). In the case of the shovel 200, if the fully automatic driving function is enabled, the interior of the cabin 10 may be unoccupied. Furthermore, the semi-automatic driving function and fully automatic driving function may include a mode in which the operation content of the driven elements (actuators) subject to automatic driving is automatically determined according to predetermined rules. Furthermore, the semi-automatic driving function and fully automatic driving function may also include a mode in which the shovel 200 autonomously makes various judgments, and the operation content of the driven elements (actuators) subject to automatic driving is autonomously determined according to the results of those judgments (a so-called "autonomous driving function").

[0025] [Shovel configuration] Next, with reference to Figure 1 and Figure 2, the configuration of the shovel 200 according to this embodiment will be described.

[0026] Figure 2 is a schematic block diagram showing an example of the configuration of the shovel 200 according to this embodiment.

[0027] In Figure 2, mechanical power lines are shown as double lines, hydraulic lines as thick solid lines, pilot lines as dashed lines, and electric drive / control lines as thin solid lines.

[0028] <Hydraulic drive system> The hydraulic drive system of the excavator 200 according to this embodiment includes hydraulic travel motors 1R and 1L, a swing hydraulic motor 2M, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, which hydraulically drive each of the driven elements such as the lower traveling body 1, boom 4, arm 5, and bucket 6. The hydraulic drive system of the excavator 200 according to this embodiment also includes a pump motor 12, a main pump 14, and a control valve 17.

[0029] The pump motor 12 (an example of a motor) is the power source for the hydraulic drive system. The pump motor 12 is, for example, an IPM (Interior Permanent Magnet) motor. The pump motor 12 is connected to a high-voltage power supply including a battery module 19 and a power converter 100 via an inverter 18A. The pump motor 12 is powered by three-phase AC power supplied from the battery module 19 via the inverter 18A and drives the main pump 14 and the pilot pump 15. The drive control of the pump motor 12 may be performed by the inverter 18A under the control of the shovel controller 30, which will be described later.

[0030] The main pump 14 draws hydraulic fluid from the hydraulic fluid tank T and discharges it into the high-pressure hydraulic line 16, thereby supplying hydraulic fluid to the control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by a pump motor 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and under the control of the shovel controller 30 (described later), the regulator 14a controls the angle (tilt angle) of the swash plate. This allows the main pump 14 to adjust the piston stroke length and thus adjust the discharge flow rate (discharge pressure).

[0031] The main pump 14 may be driven by power from another power source in addition to the electric motor 12 for the pump. For example, the energy of the hydraulic fluid discharged from the boom cylinder 7 and arm cylinder 8 to the hydraulic fluid tank T due to the weight of the boom 4 and arm 5 during the lowering operation of the boom 4 and the closing operation of the arm 5 may be recovered and used to drive the main pump 14. Specifically, the energy of the hydraulic fluid discharged from the boom cylinder 7 and arm cylinder 8 to the hydraulic fluid tank T due to the weight of the boom 4 and arm 5 during the lowering operation of the boom 4 and the closing operation of the arm 5 may be used to drive a hydraulic motor arranged coaxially with the rotation axis of the main pump 14. Alternatively, the energy of the hydraulic fluid discharged from the boom cylinder 7 and arm cylinder 8 to the hydraulic fluid tank T due to the weight of the boom 4 and arm 5 during the lowering operation of the boom 4 and the closing operation of the arm 5 may be recovered and used to generate electricity in a generator. Specifically, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic fluid discharged from the boom cylinder 7 and arm cylinder 8 into the hydraulic fluid tank T due to the weight of the boom 4 and arm 5 can be used to drive a hydraulic motor arranged coaxially with the generator, thereby causing the generator to generate electricity. In this case, the power generated by the generator may be supplied to the pump motor 12 or used to charge the battery module 19.

[0032] The control valve 17 is a hydraulic control device that controls the hydraulic drive system in response to operator commands or automatic driving functions. 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 hydraulic fluid from the main pump 14 to the hydraulic actuators (travel hydraulic motors 1R, 1L, swing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9). For example, the control valve 17 is a valve unit that includes multiple control valves (directional control valves) that control the flow rate and direction of the hydraulic fluid supplied from the main pump 14 to each of the hydraulic actuators. The hydraulic fluid supplied from the main pump 14 and that has passed through the control valve 17 and hydraulic actuators is discharged from the control valve 17 to the hydraulic fluid tank T.

[0033] The discharge pressure sensor 29A is a sensor that detects the discharge pressure of the main pump 14 and outputs the detected value to the shovel controller 30.

[0034] In this embodiment, a temperature sensor 14b is provided between the hydraulic oil tank T and the main pump 14 where the hydraulic oil is drawn in. The temperature sensor 14b detects the temperature of the hydraulic oil in the hydraulic drive system. The temperature sensor 14b may be located, for example, just before the intake port of the main pump 14. This embodiment does not restrict the location where the temperature sensor 14b can be provided; it can be located anywhere that can detect the temperature of the hydraulic oil in the hydraulic drive system.

[0035] <Electric drive system> The electric drive system of the shovel 200 according to this embodiment includes a pump motor 12, a sensor 12s, and an inverter 18A. The electric drive system of the shovel 200 according to this embodiment also includes a high-voltage power supply consisting of a battery module 19 and a power converter 100, etc.

[0036] Sensor 12s includes a current sensor 12s1, a voltage sensor 12s2, and a rotational state sensor 12s3.

[0037] 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 installed, for example, in the power path between the pump motor 12 and the inverter 18A. The detection signals corresponding to each of the three phases of the pump motor 12 detected by the current sensor 12s1 are directly input to the inverter 18A via a communication line. Alternatively, these detection signals may be input to the shovel controller 30 via a communication line and input to the inverter 18A via the shovel controller 30.

[0038] The voltage sensor 12s2 detects the applied voltage to each of the three phases of the pump motor 12. The voltage sensor 12s2 is installed, for example, in the power path between the pump motor 12 and the inverter 18A. The detection signals corresponding to the applied voltages of each of the three phases of the pump motor 12 detected by the voltage sensor 12s2 are directly input to the inverter 18A via a communication line. Alternatively, these detection signals may be input to the shovel controller 30 via a communication line and input to the inverter 18A via the shovel controller 30.

[0039] The rotational state sensor 12s3 detects the rotational state of the pump motor 12 (e.g., rotational position (rotation angle), rotational speed, etc.). The rotational state sensor 12s3 is, for example, a rotary encoder or a resolver.

[0040] The inverter 18A drives the pump motor 12 under the control of the shovel controller 30. The inverter 18A includes, for example, a conversion circuit that converts DC power to three-phase AC power and three-phase AC power to DC power, a drive circuit that switches and drives the conversion circuit, and a control circuit that outputs a control signal (for example, a PWM (Pulse Width Modulation) signal) that defines the operation of the drive circuit.

[0041] The control circuit of the inverter 18A controls the drive of the pump motor 12 while monitoring its operating state. For example, the control circuit of the inverter 18A monitors the operating state of the pump motor 12 based on the detection signal of the rotation state sensor 12s3. Alternatively, the control circuit of the inverter 18A may monitor the operating state of the pump motor 12 by sequentially estimating the rotation angle of the rotation 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).

[0042] Furthermore, at least one of the drive circuit and control circuit of the inverter 18A may be provided outside the inverter 18A.

[0043] The battery module 19 is configured to supply charged power to the electronic components within the shovel 200. The specific configuration will be described later.

[0044] The power converter 100 either boosts the power to the battery module 19 or reduces the power from the pump motor 12 via the inverter 18A and stores it in the battery module 19. The power converter 100 switches between boosting and bucking operations depending on the operating state of the pump motor 12 so that the voltage value of the DC (Direct Current) bus 110 stays within a certain range. The switching control between the boosting and bucking operations of the power converter 100 may be performed by the shovel controller 30, for example, based on the voltage detection value of the DC bus 110, the voltage detection value of the battery module 19, and the current detection value of the battery module 19.

[0045] Furthermore, if it is not necessary to boost the output voltage of the battery module 19 and apply it to the pump motor 12, the power converter 100 may be omitted.

[0046] <Operation system> The operating system of the shovel 200 according to this embodiment includes a pilot pump 15, an operating device 26, and a pressure control valve 31.

[0047] The pilot pump 15 supplies pilot pressure to various hydraulic devices (e.g., pressure control valve 31) mounted on the shovel 200 via the pilot line 25. This allows the pressure control valve 31 to supply pilot pressure to the control valve 17 according to the operation of the operating device 26 (e.g., operating amount and direction) under the control of the shovel controller 30. Therefore, the shovel controller 30 and the pressure control valve 31 can realize the operation of the driven element (hydraulic actuator) according to the operation of the operating device 26 by the operator. Furthermore, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the remote operation content specified by the remote operation signal under the control of the shovel controller 30. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump and is driven by the pump motor 12 as described above.

[0048] The control device 26 is located within reach of the operator in the cockpit of the cabin 10 and is used by the operator to operate each of the driven elements (i.e., the left and right crawlers of the lower traveling body 1, the upper slewing body 3, the boom 4, the arm 5, and the bucket 6, etc.). In other words, the control device 26 is used by the operator to operate the hydraulic actuators (e.g., travel hydraulic motors 1R, 1L, slewing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9, etc.) or electric actuators that drive each of the driven elements. The control device 26 is, for example, electrically operated and outputs an electrical signal (hereinafter referred to as "operation signal") corresponding to the operator's operation. The operation signal output from the control device 26 is taken up by the shovel controller 30. As a result, the shovel controller 30 controls the pressure control valve 31 and can control the operation of the driven elements (actuators) of the shovel 200 in accordance with the operator's operation and operation commands corresponding to the automatic driving function.

[0049] The operating device 26 includes, for example, levers 26A to 26C. Lever 26A may be configured to accept operations on the arm 5 (arm cylinder 8) and the upper slewing body 3 (slewing motion) in response to forward / backward and left / right movements, respectively. Lever 26B may be configured to accept operations on the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) in response to forward / backward and left / right movements, respectively. Lever 26C may be configured to accept operations on the lower traveling body 1 (crawler), for example.

[0050] Furthermore, if the control valve 17 is composed of an electromagnetic pilot-operated control valve (directional control valve), the operating signal from the electric operating device 26 may be directly input to the control valve 17, and each hydraulic control valve may perform an operation according to the operation of the operating device 26. Alternatively, the operating device 26 may be a hydraulic pilot type that outputs a pilot pressure according to the operation. In this case, the pilot pressure according to the operation is supplied to the control valve 17.

[0051] The pressure control valve 31 outputs a predetermined pilot pressure using hydraulic fluid supplied from the pilot pump 15 through the pilot line 25 under the control of the shovel controller 30. The pilot line on the secondary side of the pressure control valve 31 is connected to the control valve 17, and the pilot pressure output from the pressure control valve 31 is supplied to the control valve 17.

[0052] <Power system> Shovel 200 includes a vehicle inlet 101 for normal charging and a vehicle inlet 102 for rapid charging as a configuration for charging the battery module 19.

[0053] The vehicle inlet 101 for normal charging is configured to be connectable to a charging connector provided at the tip of a predetermined cable (hereinafter referred to as "charging cable") of an external power supply.

[0054] The AC-DC converter 103 for charging converts AC power supplied from an external power source via the vehicle inlet 101 for normal charging into DC power that can be used to charge the battery 192, and supplies it to the battery module 19.

[0055] The rapid charging vehicle inlet 102 is configured to be connectable to a charging connector provided at the end of a charging cable of an external power source (e.g., a power supply station). The rapid charging vehicle inlet 102 is, for example, an inlet for performing rapid charging based on CHAdeMO®. In this embodiment, by using such a DC charging method, DC power can be supplied to the battery module 19 without going through an AC-DC converter.

[0056] The battery module 19 of the excavator 200 according to this embodiment supplies power to each component within the excavator 200. The battery module 19 includes a battery 192 and a battery controller 191.

[0057] The battery 192 supplies power to various components within the shovel 200. For example, the battery 192 supplies charged (stored) power to the pump motor 12. The battery 192 also charges the power generated (regenerative power) of the pump motor 12.

[0058] Battery 192 is charged (stored of energy) by being connected to an external power source via a charging cable.

[0059] Battery 192 is, for example, a lithium-ion battery and has a relatively high output voltage (e.g., several hundred volts).

[0060] The battery controller 191 (an example of a control unit) controls the internal configuration of the battery module 19. For example, the battery controller 191 monitors the temperature status of the battery 192 and calculates the State of Charge (SOC) of the battery 192. The battery controller 191 then outputs the calculated SOC to the shovel controller 30. This allows the shovel controller 30 to display the SOC of the battery 192 on the output device 50 (display device) inside the cabin 10.

[0061] The battery controller 191 determines whether power can be supplied based on whether it is connected to an external power source via a charging cable through the normal charging vehicle inlet 101 or the rapid charging vehicle inlet 102. In this embodiment, the determination of whether power can be supplied is based on whether a charging cable is connected between the external power source and the shovel 200. However, this embodiment does not limit the method for determining whether power can be supplied to determining whether power can be supplied based on whether a charging cable is connected. For example, in the case of wireless power supply, other methods may be used, such as determining whether power can be supplied by mutual communication with a charging facility equipped with an external power source.

[0062] The battery controller 191 then communicates with the charging equipment that has an external power source (for example, a power supply station) when it determines that it is connected to an external power source via a charging cable (in other words, when it determines that it is in a state where power can be supplied). The battery controller 191 then communicates with the charging equipment and, if the charging equipment authorizes the supply of power, power supply from the external power source is initiated.

[0063] Furthermore, the battery controller 191 receives information indicating the power supply capacity of the power supply station through communication with the power supply station. The battery controller 191 transmits the information indicating the power supply capacity of the power supply station to the shovel controller 30.

[0064] <Control System> The control system of the shovel 200 according to this embodiment includes a shovel controller 30, an output device 50, an input device 52, the communication device 91 (described above), and an outside air temperature sensor 92.

[0065] The output device 50 is located inside the cabin 10 and outputs various information to the operator under the control of the shovel controller 30. The output device 50 includes, for example, a display device that outputs (notifies) information to the operator in a visual manner. The display device may be, for example, installed in a location easily visible to the operator inside the cabin 10 and displaying various information images under the control of the shovel controller 30. The display device may be, for example, a liquid crystal display or an organic EL (electroluminescence) display. The output device 50 also includes, for example, a sound output device that outputs information to the operator in an auditory manner. The sound output device may be, for example, a buzzer or a speaker.

[0066] The input device 52 is located inside the cabin 10 and receives various inputs from the operator. The input device 52 may include, for example, an operation input device that receives operation inputs from the operator. The operation input device includes, for example, buttons, toggles, levers, touch panels, touch pads, etc. The input device 52 may also include, for example, an audio input device that receives voice inputs from the operator and a gesture input device that receives gesture inputs from the operator. The audio input device includes, for example, a microphone that acquires the voice of the operator inside the cabin 10. The gesture input device includes, for example, an indoor camera capable of capturing images of the operator's gestures inside the cabin 10. Signals corresponding to the operator inputs received by the input device 52 are taken up by the shovel controller 30.

[0067] The ambient temperature sensor 92 detects the ambient temperature around the shovel 200. The ambient temperature sensor 92 can be installed at any location.

[0068] The shovel controller 30 may implement each function using any hardware, or any combination of hardware and software. For example, the shovel controller 30 may be centered around a computer that includes a processor such as a CPU (Central Processing Unit), a memory device (main memory) such as RAM (Random Access Memory), a non-volatile auxiliary storage device such as ROM (Read Only Memory), and an interface device for input / output with the outside.

[0069] The shovel controller 30 controls the drive of the shovel 200. For example, the shovel controller 30 outputs a control command to the pressure control valve 31 in response to an operation signal input from the operating device 26, and the pressure control valve 31 outputs a pilot pressure corresponding to the operation of the operating device 26. In this way, the shovel controller 30 can realize the operation of the driven elements (hydraulic actuators) of the shovel 200 that correspond to the operation of the electric operating device 26.

[0070] Furthermore, if the shovel 200 is remotely controlled, the shovel controller 30 may, for example, perform control related to the remote operation. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31, causing the pressure control valve 31 to output a pilot pressure corresponding to the remote operation. This allows the shovel controller 30 to realize the operation of the shovel 200 (driven element) corresponding to the remote operation.

[0071] Furthermore, the shovel controller 30 may also perform control related to the automatic driving function, for example. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31 and apply a pilot pressure corresponding to the operation command for the automatic driving function from the pressure control valve 31 to the control valve 17. In this way, the shovel controller 30 can realize the operation of the driven elements (hydraulic actuators) of the shovel 200 that correspond to the automatic driving function.

[0072] The shovel controller 30 may comprehensively control the operation of the entire shovel 200 (various devices mounted on the shovel 200).

[0073] The shovel controller 30 may communicate with the communication device 91 using a predetermined mobile communication standard (e.g., LTE, 4G, or 5G) to perform wireless communication with an external device (e.g., a mobile terminal used by an operator riding the shovel 200). In this embodiment, the wireless communication between the shovel controller 30 and the external device is shown as one example, and wireless communication using other wireless communication standards (e.g., Bluetooth®, Wi-Fi®) may also be performed.

[0074] The shovel controller 30 performs drive control of the electric drive system based on various input information (for example, control commands including the operation signals of the operating device 26).

[0075] Furthermore, the shovel controller 30 may, for example, drive the power converter 100 based on the operating state of the operating device 26 and control the switching between boost and buck operation of the power converter 100, in other words, between the discharge state and the charge state of the battery module 19. Also, if the shovel 200 is remotely operated, the shovel controller 30 may, for example, drive the power converter 100 based on the content of the remote operation and control the switching between the discharge state and the charge state of the battery module 19. Furthermore, if the automatic operation function of the shovel 200 is enabled, the shovel controller 30 may, for example, drive the power converter 100 based on the operation command corresponding to the automatic operation function and control the switching between the discharge state and the charge state of the battery module 19.

[0076] Furthermore, the shovel controller 30 performs various calculations based on the values ​​detected by, for example, the discharge pressure sensor 29A and the ambient temperature sensor 92, and outputs various commands to the regulator 14a, the pump motor 12, the inverter 18A, the battery module 19, etc. For example, before work begins, if the shovel controller 30 determines, based on the value detected by the ambient temperature sensor 92, that the ambient temperature is below a predetermined reference temperature (for example, 0 degrees), it performs warm-up of the hydraulic drive system. The predetermined reference temperature is the temperature defined as the criterion for whether or not to warm up the hydraulic drive system. The various functional blocks provided by the shovel controller 30 for warming up the hydraulic drive system will be described later.

[0077] <Detailed explanation of the hydraulic drive system used for warming up the engine> Figure 3 is a schematic diagram of the hydraulic circuit (hydraulic drive system) installed in the excavator 200 according to this embodiment. The high-pressure oil passage, pilot oil passage, and electrical control line are shown as solid, dashed, and dotted lines, respectively. In this embodiment, warm-up is performed to raise the temperature of the hydraulic fluid flowing through the hydraulic circuit.

[0078] In this embodiment, the main pump 14 is composed of two main pumps 14L and 14R, and the regulator 14a is composed of two regulators 14aL and 14aR. Regulator 14aL corresponds to main pump 14L, and regulator 14aR corresponds to main pump 14R. The discharge pressure sensor 29A is composed of two discharge pressure sensors 29AL and 29AR. Discharge pressure sensor 29AL corresponds to main pump 14L, and discharge pressure sensor 29AR corresponds to main pump 14R. In this embodiment, the temperature sensor 14b detects the temperature of the hydraulic oil flowing through the oil passage from the hydraulic oil tank T to the main pump 14R. The temperature sensor 14b outputs the detection result to the shovel controller 30.

[0079] The hydraulic circuit circulates hydraulic fluid from the main pumps 14L and 14R, through the center bypass oil passages 40L and 40R, respectively, to the hydraulic fluid tank T.

[0080] The center bypass oil passage 40L is a high-pressure oil passage that passes through flow control valves 150 to 152. A relief valve 50L is installed upstream of flow control valve 150. Similarly, the center bypass oil passage 40R is a high-pressure oil passage that passes through flow control valves 153 to 156. A relief valve 50R is installed upstream of flow control valve 153.

[0081] Flow control valve 150 is a spool valve that controls the flow rate and direction of the hydraulic fluid flowing through the left-side travel hydraulic motor 1L. Flow control valve 153 is a spool valve that controls the flow rate and direction of the hydraulic fluid flowing through the right-side travel hydraulic motor 1R. Flow control valve 154 is a spool valve that controls the flow rate and direction of the hydraulic fluid flowing through the bucket cylinder 9. Flow control valves 151 and 155 are spool valves that control the flow rate and direction of the hydraulic fluid flowing through the boom cylinder 7. Flow control valves 152 and 156 are spool valves that control the flow rate and direction of the hydraulic fluid flowing through the arm cylinder 8.

[0082] Relief valves 50L and 50R are valves that suppress the pressure of the hydraulic fluid in the center bypass oil passages 40L and 40R to below a predetermined pressure. Specifically, relief valves 50L and 50R open when the pressure of the hydraulic fluid in the center bypass oil passages 40L and 40R reaches a predetermined pressure, releasing the hydraulic fluid into the hydraulic fluid tank T.

[0083] In this embodiment, electromagnetic proportional relief valves are used as the relief valves 50L and 50R. In electromagnetic proportional relief valves, the pressure is adjusted by a proportional solenoid instead of a pressure adjustment screw like in a direct-acting relief valve. In other words, the relief valves 50L and 50R according to this embodiment can maintain the pressure in the hydraulic circuit (hydraulic drive system) at the set value from the shovel controller 30.

[0084] In this embodiment, the shovel controller 30 controls the temperature of the hydraulic fluid flowing through the hydraulic circuit (hydraulic drive system) to increase (warm up). For example, the shovel controller 30 controls the hydraulic fluid discharged by the main pump 14R so that it cannot flow into the bottom oil chamber of the bucket cylinder 9, and then controls the pressure of the hydraulic fluid in the center bypass oil passage 40R to increase, as shown by the thick line in Figure 3. As a result, the hydraulic fluid discharged by the main pump 14R is released into the hydraulic fluid tank T through the relief valve 50R, generating heat due to pressure loss caused by pipeline resistance when passing through the relief valve 50R. As a result, the hydraulic fluid circulating in the hydraulic circuit is warmed. As a control to prevent the fluid from flowing into the bottom oil chamber of the bucket cylinder 9, for example, the bucket 6 is closed and the closing operation of the bucket 6 is continued for a predetermined time (for example, 30 seconds), or the bucket 6 is opened and the opening operation of the bucket 6 is continued for a predetermined time (for example, 30 seconds). Furthermore, the shovel controller 30 may raise the temperature of the hydraulic fluid by repeatedly controlling the opening and closing of the bucket 6.

[0085] Furthermore, the shovel controller 30 may increase the pressure of the hydraulic fluid and raise the temperature of the hydraulic fluid by controlling, for example, the opening and closing of the arm 5, or other controls other than the opening and closing control of the bucket 6, to prevent the fluid from flowing into a predetermined oil chamber.

[0086] This embodiment describes an example in which a pump motor 12 (an example of a predetermined device) is driven to circulate the hydraulic circuit (hydraulic drive system), thereby warming the hydraulic fluid circulating in the hydraulic circuit using the heat generated by pressure loss due to pipeline resistance. However, the method of warming the hydraulic fluid circulating in the hydraulic circuit is not limited to a method of warming the hydraulic fluid using pipeline resistance (an example of resistance). Any method can be used as long as it is possible to warm the hydraulic fluid circulating in the hydraulic circuit. For example, an electrical device (an example of a predetermined device) may be operated to generate heat in the electrical device, and this heat may be transferred to the hydraulic circuit (hydraulic drive system) to warm up the hydraulic fluid. As another example, the electrical device (an example of a predetermined device) may not be operated, but the electrical device may be energized to generate heat in the electrical device, and this heat may be transferred to the hydraulic circuit (hydraulic drive system) to warm up the hydraulic fluid. As an example of an electronic device (an example of a predetermined device), a heating element may be used, for example. Thus, this embodiment shows one example of warming up a hydraulic drive system, and the warm-up of the hydraulic drive system may be performed in other ways.

[0087] <Excavator Controller Function Blocks> Returning to Figure 2, let's describe each functional block within the shovel controller 30. Each functional block within the shovel controller 30 is conceptual and does not necessarily need to be physically configured as shown in the figure. It is possible to configure all or part of each functional block by distributing and integrating them functionally or physically in any unit. Each processing function performed in each functional block is realized, all or any part thereof, by a program executed on the CPU. Alternatively, each functional block may be realized as hardware using wired logic.

[0088] In this embodiment, the excavator controller 30 controls the pump motor 12 (an example of a predetermined device) to be driven by power supplied from the power supply station when it is connected to the power supply station (an example of an external power source) and the vehicle inlet 101 for normal charging or the vehicle inlet 102 for rapid charging via a charging cable, thereby warming up the hydraulic drive system. The specific control will be described later.

[0089] Incidentally, with the Shovel 200, the warm-up time for the hydraulic drive system increases with lower ambient temperatures. Therefore, if the operator performs warm-up operations from the start of work, raising the hydraulic fluid temperature to a suitable temperature for work may delay the actual work.

[0090] On the other hand, the Shovel 200 is electrically powered and does not have an engine, so there is no need to start the engine when warming up the hydraulic drive system. However, in conventional excavators that have an engine, when the engine is driven, the sound of the engine running can be heard around the excavator. This allows people around a conventional excavator to recognize that the excavator is in operation. People around an excavator tend to feel uneasy if they realize that there is no operator on board despite the engine being in operation. For this reason, many people feel uncomfortable with operating an excavator engine without an operator on board.

[0091] On the other hand, in the excavator 200 according to this embodiment, the hydraulic drive system is warmed up by the operation of the pump motor 12. The operating noise of the pump motor 12 is quieter than the operating noise of the engine. Therefore, people in the vicinity of the excavator 200 will not feel any discomfort even if the pump motor 12 is driven to warm up the hydraulic drive system, even if there is no operator on board. In other words, in the excavator 200 according to this embodiment, it is easy to warm up the hydraulic drive system using electricity supplied from the power supply station, even if there is no operator on board.

[0092] Therefore, the shovel controller 30 according to this embodiment controls the system to ensure that the working oil in the hydraulic drive system is warmed up before work begins, using power supplied from a power supply station (an example of an external power source). For this purpose, as shown in Figure 2, the shovel controller 30 includes, as functional blocks, an acquisition unit 301, a charge control unit 302, a setting unit 303, and a warm-up control unit 304. Furthermore, the shovel controller 30 includes, as an example of a storage unit, a non-volatile auxiliary storage device (an example of a storage device), a setting time holding unit 305, a capability information holding unit 306, and a warm-up time holding unit 307.

[0093] The acquisition unit 301 acquires signals from various components within the shovel 200. For example, the acquisition unit 301 acquires the detected value from the discharge pressure sensor 29A, the ambient temperature from the ambient temperature sensor 92, and the temperature of the working oil from the temperature sensor 14b.

[0094] Furthermore, the acquisition unit 301 acquires power supply capacity information from the battery controller 191 of an external power source (e.g., a power supply station). The power supply capacity information includes the maximum power that the external power source (e.g., a power supply station) can supply. The acquisition unit 301 then stores the acquired power supply capacity information in the capacity information holding unit 306.

[0095] Furthermore, the acquisition unit 301 acquires the start time information of the shovel 200, which is input via the input device 52. The acquisition unit 301 may also acquire the start time information of the shovel 200, which is received from an external device (for example, a mobile terminal used by the operator, such as a smartphone) via the communication device 91. The acquisition unit 301 stores the acquired start time information in the set time holding unit 305. The acquisition unit 301 may also acquire selection information on whether or not to warm up the shovel via the input device 52. If the acquisition unit 301 can acquire selection information, the shovel controller 30 may switch the control to warm up the shovel or not according to the selection information. In this embodiment, the control when warming up the shovel is performed will be described.

[0096] The work start time information is information indicating the time when the shovel 200 will start work, and for example, it stores "Monday; 8:00" as the work start time for each day of the week. The shovel controller 30 in this embodiment prepares so that work can start at the work start time indicated by the work start time information.

[0097] The setting time holding unit 305 holds the work start time information written to the acquisition unit 301. Furthermore, the work start time information held by the setting time holding unit 305 is not limited to cases where the operator on board the shovel 200 inputs it as operation information via the input device 52 (an example of a predetermined device) or where the operator transmits it as operation information from an external device (an example of a predetermined device). For example, the setting time holding unit 305 may hold the work start time information for each date, which is automatically set according to the work schedule information created in advance by the management center that manages the work site. Moreover, the auxiliary storage device may store work history information including past work start and end times of the shovel 200, the shovel controller 30 may estimate the work start time information for each date based on the work history information, and the setting time holding unit 305 may store the estimated work start time information for each date.

[0098] The charging control unit 302 instructs the battery controller 191 to complete charging at the work start time indicated by the work start time information.

[0099] Specifically, the charging control unit 302 calculates the charging time based on the charging power when charging the battery 192 from an external power source and the State of Charge (SOC) of the battery 192 received from the battery controller 191, and instructs the battery controller 191 to start charging at the time obtained by subtracting the charging time from the start time of work.

[0100] The setting unit 303 makes settings to complete the warm-up of the hydraulic drive system's working oil at the work start time indicated by the work start time information.

[0101] In this embodiment, the setting unit 303 sets the pump motor 12 to be driven with power supplied from an external power source to warm up the hydraulic drive system while the charging control unit 302 is controlling the charging of the battery 192 with power supplied from an external power source.

[0102] First, the setting unit 303 reads the power supply capacity information from the capacity information holding unit 306. Then, the setting unit 303 subtracts the charging power used to charge the battery 192 from the power supply capacity (power that can be supplied) of the external power source (e.g., power supply station) as shown in the power supply capacity information, to calculate the power available to the pump motor 12 for warming up (hereinafter referred to as motor usable power). In this embodiment, for the sake of simplicity, an example is described in which the power obtained by subtracting the charging power from the power supply capacity is used as the motor usable power. However, if other components use power to perform warming up, the power used by those components may also be subtracted.

[0103] The setting unit 303 then calculates the warm-up time for the working oil based on the motor's usable power, hydraulic load, ambient temperature, and the working oil temperature. The hydraulic load is defined as the pressure load generated on the working oil flowing through the relief valves 50L and 50R. In this embodiment, the maximum hydraulic load value that the relief valves 50L and 50R can output is referred to as the maximum hydraulic load.

[0104] Furthermore, when calculating the warm-up time for the working oil, the setting unit 303 refers to the warm-up time information stored in the warm-up time retention unit 307.

[0105] Figure 4 is a diagram illustrating the warm-up time information stored in the warm-up time holding unit 307 according to this embodiment. As shown in Figure 4, in this embodiment, warm-up time information is provided for each ambient temperature at which the shovel 200 operates. In this embodiment, we will use the example of warming up the working oil to 50 degrees. In this case, for example, the warm-up time information may be provided for ambient temperatures between "-20 degrees" and "50 degrees". In this embodiment, the explanation is given when the temperature of the working oil to complete the warm-up is "50 degrees", but this is just an example and does not limit the temperature of the working oil to complete the warm-up.

[0106] For example, warm-up time information 1401 is used when calculating the warm-up time when the outside temperature is "-20°C". Similarly, warm-up time information 1402 is used when calculating the warm-up time when the outside temperature is "0°C". The warm-up time information is generated for each outside temperature, and the warm-up time information for other outside temperatures is the same as warm-up time information 1401 and 1402, so no further explanation is provided.

[0107] As shown in Figure 4, the warm-up time information 1401 and 1402 have the warm-up time on the vertical axis and the motor power consumption on the horizontal axis. The warm-up time information 1401 and 1402 show the relationship between the motor power consumption and the warm-up time required to raise the temperature of the hydraulic fluid from the same temperature as the ambient temperature, for each difference temperature indicated by "hydraulic oil temperature - ambient temperature".

[0108] Motor power consumption refers to the amount of power supplied to the pump motor 12 during warm-up. Motor power consumption is set according to the available motor power and the hydraulic load (including the maximum hydraulic load).

[0109] The setting unit 303 sets the motor power to the power corresponding to the maximum hydraulic load (the power required to flow hydraulic fluid when the relief valves 50L and 50R are at maximum hydraulic load) if the motor's usable power is greater than or equal to the maximum hydraulic load.

[0110] Furthermore, if the motor's usable power is less than the maximum hydraulic load, the setting unit 303 sets the motor's usable power as the motor's usable power. In addition, the setting unit 303 makes settings for the relief valves 50L and 50R so that the hydraulic load corresponds to the motor's usable power. After the warm-up control is started, the warm-up control unit 304 controls the relief valves 50L and 50R based on the settings, while checking the value detected by the discharge pressure sensor 29A, so that the hydraulic load corresponds to the motor's usable power.

[0111] In Figure 4, line 1401a of the warm-up time information 1401 represents the case where "hydraulic oil temperature - ambient temperature" = 70 degrees. In other words, line 1401a is used to determine the warm-up time required to warm up the hydraulic oil from the ambient temperature of "-20 degrees" to the target hydraulic oil temperature of "50 degrees".

[0112] Similarly, line 1402a of the warm-up time information 1402 assumes that "hydraulic oil temperature - ambient temperature" = 50 degrees. In other words, line 1402a is used when determining the warm-up time required to warm up the engine from "0 degrees," when the hydraulic oil temperature is the same as the ambient temperature, to the target hydraulic oil temperature of "50 degrees."

[0113] Specifically, the setting unit 303 identifies warm-up time information to be referenced based on the ambient temperature, and then, while referring to the identified warm-up time information, derives the warm-up time from the current hydraulic fluid temperature and motor power consumption.

[0114] If the temperature of the hydraulic fluid detected by the temperature sensor 14b is approximately equal to the ambient temperature detected by the ambient temperature sensor 92, the setting unit 303 can derive the warm-up time from the line specified by "hydraulic fluid temperature - ambient temperature" and the motor power consumption.

[0115] Furthermore, there are cases where the temperature of the hydraulic fluid is warmer than the ambient temperature. In such cases, the setting unit 303 derives the actual warm-up time from the difference between the warm-up time derived from the line "target hydraulic fluid temperature - ambient temperature" and the warm-up time derived from the line "current hydraulic fluid temperature - ambient temperature".

[0116] The warm-up control unit 304 starts controlling the pump motor 12 with power supplied from an external power source to warm up the hydraulic drive system, starting from a time obtained by subtracting the warm-up time from the start of work.

[0117] The warm-up control unit 304 then completes the warm-up of the hydraulic drive system when the temperature of the hydraulic fluid contained in the hydraulic drive system reaches or exceeds the target working fluid temperature (an example of a predetermined value).

[0118] When warming up is performed using the control described above, the time when the warming up of the hydraulic fluid is completed will be the start time of work. At approximately the same time that the warming up of the hydraulic fluid by the warming-up control unit 304 is completed (for example, the start time of work), the charging control unit 302 will also complete charging of the battery 192. In this embodiment, an example was described in which the warming-up control unit 304 performs warming up from a time obtained by subtracting the warming-up time from the start time of work, so that warming up is completed exactly at the start time of work. However, this embodiment is not limited to the example in which warming up is completed exactly at the start time of work. For example, a buffer may be included in the warming-up time so that warming up is completed a little before the start time of work. It is sufficient that warming up and charging are completed at the start time of work so that work can begin.

[0119] Furthermore, the warm-up control unit 304 according to this embodiment is not limited to a method of completing warm-up if the target working oil temperature (an example of a predetermined value) is reached before the start of work. For example, the warm-up control unit 304 may continue warming up the hydraulic drive system until the start of work so that the temperature of the hydraulic fluid contained in the hydraulic drive system is maintained within a predetermined temperature range (for example, a range from the target working oil temperature to the target working oil temperature minus 10 degrees). The method of warming up the hydraulic drive system only needs to be able to maintain the predetermined temperature range, and the pump motor 12 may be driven and stopped repeatedly, or the pump motor 12 may be driven continuously.

[0120] Furthermore, if a predetermined time has elapsed from the start of work and work by the shovel 200 has not started, and the temperature of the hydraulic fluid has dropped, the warm-up control unit 304 may restart the control to warm up the hydraulic drive system by driving the electric motor 12 for the pump with power supplied from an external power source. However, this embodiment is not limited to this control method, and the warm-up control unit 304 does not need to perform any special control even if a predetermined time has elapsed from the start of work and work by the shovel 200 has not started, and the temperature of the hydraulic fluid has dropped.

[0121] In the control described above, an example was described in which the warm-up control unit 304 completes the warm-up of the hydraulic fluid before the start of work. However, this embodiment is not limited to the example in which the warm-up of the hydraulic fluid is completed before the start of work. In other words, even if the warm-up of the hydraulic fluid is not completed before the start of work, it is sufficient if the warm-up is performed and the temperature of the hydraulic fluid rises before the start of work. For example, the warm-up control unit 304 may warm the hydraulic fluid so that its temperature rises by 10 degrees at the start of work. Thus, in the warm-up control unit 304 of this embodiment, it is sufficient if the warm-up of the hydraulic fluid is started before the start of work, based on the start of work. Since the warm-up is started before the start of work, the time required to start work can be shortened.

[0122] <Charging and warm-up process before the start of work> Next, the charging and warm-up procedures performed in the shovel controller 30 before the start of work will be described. Figure 5 is a flowchart showing the charging and warm-up procedures performed in the shovel controller 30 before the start of work according to this embodiment.

[0123] The acquisition unit 301 stores the start time information of the shovel 200, which has been input via the input device 52, etc., in the set time holding unit 305 (S1501).

[0124] The battery controller 191 determines whether the vehicle inlet 101 for normal charging or the vehicle inlet 102 for rapid charging is connected to a power supply station (external power source) via a charging cable (S1502). If it is not connected (S1502: No), the determination is repeated until it is connected.

[0125] If the battery controller 191 determines that the vehicle inlet 101 for normal charging or the vehicle inlet 102 for rapid charging is connected to a power supply station (external power source) via a charging cable (S1502: Yes), it communicates with the power supply station to receive power supply capacity information from the power supply station, and the acquisition unit 301 stores the power supply capacity information input from the battery controller 191 in the capacity information holding unit 306 (S1503).

[0126] The charging control unit 302 then calculates the charging time based on the charging power supplied to the battery 192 from the power supply station and the State of Charge (SOC) of the battery 192 received from the battery controller 191 (S1504). The charging control unit 302 then determines whether the current time is after the time obtained by subtracting the charging time from the start time of work (S1505). If it determines that the current time is before the time obtained by subtracting the charging time from the start time of work (S1505: No), the charging control unit 302 repeats this determination until the current time is the time obtained by subtracting the charging time from the start time of work.

[0127] If the charging control unit 302 determines that the current time is after the time obtained by subtracting the charging time from the start time of work (S1505: Yes), the charging control unit 302 instructs the battery controller 191 to start charging (S1506).

[0128] Subsequently, the acquisition unit 301 acquires the ambient temperature from the ambient temperature sensor 92 (S1507). Then, the setting unit 303 determines whether the ambient temperature is lower than a predetermined reference temperature (S1508). The predetermined reference temperature is the temperature used as a criterion for deciding whether or not to perform warm-up, and may be a temperature that can be set by the operator. For example, "0 degrees" may be set as the predetermined reference temperature.

[0129] If the setting unit 303 determines that the outside air temperature is above a predetermined reference temperature (S1508: No), it does not perform any warm-up control and terminates the charging control when the battery controller 191 detects that the battery 192 has become fully charged (S1518).

[0130] On the other hand, if the setting unit 303 determines that the outside temperature is lower than a predetermined reference temperature (S1508: Yes), the setting unit 303 reads the power supply capacity information from the capacity information holding unit 306 and obtains the charging power that is charging the battery 192 from the battery controller 191 (S1509).

[0131] The setting unit 303 calculates the usable motor power by subtracting the charging power used to charge the battery 192 from the power supply capacity of the power supply station, as indicated by the power supply capacity information (S1510).

[0132] The setting unit 303 then determines whether the motor's usable power is equal to or greater than the maximum hydraulic load of the relief valves 50L and 50R (S1511). If the setting unit 303 determines that the motor's usable power is less than the maximum hydraulic load (S1511: No), it sets the motor's usable power as the motor's power consumption and makes settings for the relief valves 50L and 50R so that the hydraulic load corresponds to that motor's power consumption (S1512).

[0133] On the other hand, if the setting unit 303 determines that the motor's usable power is equal to or greater than the maximum hydraulic load (S1511: Yes), it sets the power corresponding to the maximum hydraulic load as the motor's usable power (S1513).

[0134] The setting unit 303 then refers to the warm-up time information corresponding to the ambient temperature and derives the warm-up time based on the motor power consumption and the current hydraulic fluid temperature (S1514). The method for deriving the warm-up time is the same as described above and will not be explained further.

[0135] The warm-up control unit 304 then determines whether the current time is after the time obtained by subtracting the warm-up time from the start of work (S1515). If the warm-up control unit 304 determines that the current time is before the time obtained by subtracting the warm-up time from the start of work (S1515: No), it repeats this determination until the current time is the time obtained by subtracting the warm-up time from the start of work.

[0136] If the warm-up control unit 304 determines that the current time is after the time obtained by subtracting the warm-up time from the start time of work (S1515: Yes), the warm-up control unit 304 starts control to warm up the hydraulic drive system by driving the pump motor 12 with power supplied from the power supply station (S1516).

[0137] Then, the warm-up control unit 304 terminates the warm-up of the hydraulic drive system when the temperature of the hydraulic fluid reaches or exceeds the target working oil temperature (S1517).

[0138] Then, the battery controller 191 terminates the charging control (S1518) when it detects that the battery 192 has reached full charge.

[0139] The flowchart described above illustrates an example where warm-up control is performed after charging has started. However, in this embodiment, the control order is not limited to the above-described order. Rather, the control order for charging and warming up is determined based on the work start time, charging time, and warm-up time, so that warm-up and charging are completed by the work start time. Therefore, the procedure may be such that charging starts after warm-up has started.

[0140] In the flowchart described above, the order in which the warm-up control is completed followed by the charging control is shown. However, this order is not restrictive; as long as the warm-up control and charging control are completed by the start time of the operation, either one can be completed first.

[0141] In this embodiment, by performing the above-described process, when the outside temperature is low, warm-up and charging are completed by the start time of work, so the operator can immediately start working with the shovel 200.

[0142] In the embodiments described above, an example was described in which the working oil of the hydraulic drive system is warmed up while the battery 192 is being charged. However, the embodiments described above are not limited to the method of warming up the working oil of the hydraulic drive system while the battery 192 is being charged. For example, when the vehicle inlet 101 for normal charging or the vehicle inlet 102 for rapid charging is connected to a power supply station (external power source) with a charging cable, the battery 192 may be charged first, and then the working oil of the hydraulic drive system may be warmed up before the start of work. Even when such control is performed, the warming up can be done with power supplied from an external power source without using the power of the battery 192, so the number of charge and discharge cycles of the battery 192 can be suppressed and the lifespan of the battery 192 can be suppressed.

[0143] Furthermore, as described above, when the charging cable of the power supply station is connected to the standard charging vehicle inlet 101 or the rapid charging vehicle inlet 102, the charging and warming up described above will be performed. However, there are situations in which the charging cable of the power supply station is not connected to the standard charging vehicle inlet 101 or the rapid charging vehicle inlet 102.

[0144] Specifically, this could occur if the battery controller 191 does not detect the connection of the charging cable from the power supply station to the normal charging vehicle inlet 101 or the rapid charging vehicle inlet 102, or if it detects the connection of the charging cable from the power supply station but determines through communication with the power supply station that it is not in a state where charging is possible.

[0145] In the example shown in Figure 5, in S1502, if the battery controller 191 determines that the charging cable is not connected to the normal charging vehicle inlet 101 or the rapid charging vehicle inlet 102 in a chargeable manner, it repeats this determination and suppresses charging and warming up.

[0146] By the way, if the power supply station (external power source) is not connected to the battery 192 in a way that allows it to charge, the hydraulic drive system will need to be warmed up using power from the battery 192. However, if the hydraulic drive system is warmed up using power supplied from the battery 192 before the start of work, the State of Charge (SOC) of the battery 192 will decrease by the start of work. In this case, the working time of the shovel 200 may be shortened due to the decrease in SOC.

[0147] Therefore, if the power supply station (external power source) is not connected to the battery 192 in a way that allows it to charge, the warm-up control unit 304 suppresses the warm-up of the hydraulic drive system, regardless of whether the set time holding unit 305 stores the work start time information, as described above. This suppresses the reduction in the state of charge (SOC) of the battery 192 and prevents the working time from being shortened.

[0148] <Example 1> In the above-described embodiment, the warm-up control of the hydraulic drive system's working oil by the shovel controller 30 was explained in the case where a work start time is set. However, the above-described embodiment is not limited to warm-up control based on a work start time. For example, when the shovel controller 30 charges the shovel 200 during a break, it may perform warm-up while charging, similar to the above-described embodiment. This can suppress a decrease in the temperature of the hydraulic drive system's working oil during breaks.

[0149] Furthermore, if the shovel controller 30 holds the end time of the break, the above-described control may be performed so that warm-up and charging are completed by the end time of the break. By performing the above-described warm-up control during the break, work can be started immediately after the break is completed, thereby improving work efficiency.

[0150] <Modification 2> In the embodiments described above, an example was explained in which the warm-up of the hydraulic drive system is suppressed when the power supply station (an example of an external power source) is not connected to the battery 192 in a rechargeable manner. However, the method is not limited to suppressing the warm-up of the hydraulic drive system when the power supply station (an example of an external power source) is not connected to the battery 192 in a rechargeable manner. If certain conditions are met, the hydraulic drive system may be warmed up using the power supplied from the battery 192.

[0151] The specified conditions can be any conditions; for example, the shovel 200 may send an email via the communication device 91 to a mobile terminal used by the operator inquiring whether or not it is permissible to warm up using power supplied from the battery 192. When the shovel controller 30 receives a reply email via the communication device 91 in response to the inquiry, and determines that the reply email contains instructions to warm up the shovel, the warm-up control unit 304 may use power supplied from the battery 192 to drive the pump motor 12 and warm up the hydraulic drive system.

[0152] Furthermore, under certain conditions, if the operator directly receives an operation from the control device 26 or the like mounted on the shovel 200, the warm-up control unit 304 may use the power supplied from the battery 192 to warm up the hydraulic drive system, as if the conditions have been met.

[0153] <Variation 3> The conditions for the Shovel 200 to charge and warm up are not limited to conditions based on the work start time indicated in the work start time information, as in the embodiment described above, but may be determined by various methods.

[0154] For example, the acquisition unit 301 of the shovel 200 may receive at least one of the charging conditions and warm-up conditions by communicating with an external device connected via a communication network using a communication device 91. The setting unit 303 may then be configured to perform control according to at least one or more of the received charging conditions and warm-up conditions.

[0155] The charging conditions specify the conditions for charging the battery 192 from a power supply station (an example of an external power source). The charging conditions may be based on the start time of work, for example, as in the embodiment described above. Another example of charging conditions is that a start time for starting charging may be set. The charging conditions are not limited to time-related conditions and may be any conditions. For example, the charging conditions may include whether or not an operator is on board, and whether or not the State of Charge (SOC) of the battery 192 is below a predetermined reference value.

[0156] The warm-up conditions specify the conditions for warming up the hydraulic drive system. These conditions may include, for example, whether a power supply station (an example of an external power source) is rechargeably connected to the battery 192, as in the embodiment described above, or they may include conditions based on the start time of work. Furthermore, another example of a warm-up condition is that a start time for warming up may be set. The warm-up conditions are not limited to time-related conditions and may include any conditions. For example, they may include whether an operator is on board, or whether the outside air temperature is below a predetermined reference temperature.

[0157] Then, when a power supply station (an example of an external power source) is connected to the battery 192 in a way that allows it to charge, the charging control unit 302 instructs the battery controller 191 to charge the battery 192 from the power supply station according to the set charging conditions.

[0158] Similarly, the warm-up control unit 304 warms up the hydraulic drive system according to the set warm-up conditions.

[0159] External devices that transmit charging and warm-up conditions to the shovel 200 include, for example, a portable terminal used by the operator. Alternatively, the external device may be a management server that manages the work site. In other words, the management server may transmit charging and warm-up conditions to each shovel working at the work site.

[0160] The charging control unit 302 may, when it determines that the set charging conditions have been met, send charging notification information (an example of first notification information) indicating that charging will begin because the charging conditions have been met, to an external device (for example, a mobile terminal used by the operator) using the communication device 91. This transmission allows the operator to recognize in advance that charging is about to begin.

[0161] After transmitting the charging notification information, the charging control unit 302 may instruct the battery controller 191 to start charging, or it may wait.

[0162] In cases where the system is in standby mode, for example, the charging control unit 302 may wait until it receives an authorization notification (first authorization information) corresponding to the charging notification information from an external device (for example, a mobile terminal used by an operator). If the received authorization notification indicates that charging is permitted, the charging control unit 302 instructs the battery controller 191 to start charging. If no authorization notification is received, or if the authorization notification does not indicate that charging is permitted, the charging control unit 302 suppresses the instruction to the battery controller 191 to start charging.

[0163] When the warm-up control unit 304 determines that the set warm-up conditions have been met, it may send warm-up notification information (an example of second notification information) indicating that the warm-up conditions have been met and warm-up will begin to an external device (for example, a mobile terminal used by the operator) using the communication device 91. This transmission allows the operator to recognize in advance that the warm-up will begin.

[0164] After transmitting warm-up notification information, the warm-up control unit 304 may start warming up the hydraulic drive system or may remain in standby mode.

[0165] In cases where the system is in standby mode, for example, the warm-up control unit 304 may wait until it receives an authorization notification (an example of second authorization information) corresponding to the warm-up notification information from an external device (for example, a mobile terminal used by the operator). The warm-up control unit 304 starts warming up the hydraulic drive system if the received authorization notification indicates that warm-up is permitted. If no authorization notification is received, or if the authorization notification does not indicate that warm-up is permitted, the warm-up control unit 304 suppresses the warm-up of the hydraulic drive system.

[0166] Thus, in this modified version, as described above, the charging control unit 302 may wait until it receives a permission notification, or the warm-up control unit 304 may wait until it receives a permission notification. This allows the operator to recognize from their mobile terminal that charging or warming is in progress based on this notification information, and then instruct whether or not to actually allow warming or charging. In addition to instructions to charge or warm up, permission notifications may also include instructions to suppress charging or warming. This allows the operator to recognize the situation and give the desired instructions. Therefore, the usability of the Shovel 200 can be improved.

[0167] <Modification 4> Furthermore, the shovel controller 30 of the shovel 200 (including the charging control unit 302 and warm-up control unit 304 described above) may transmit various information to external devices (for example, a mobile terminal used by the operator) using the communication device 91. The transmission of information by the shovel controller to external devices (for example, a mobile terminal used by the operator) may be done using, for example, email. Moreover, the external device to which the information is transmitted by the shovel controller 30 is not limited to a mobile terminal used by the operator, but can be any device that the operator can check. For example, the destination may be a social networking service (SNS) server. In other words, when information is uploaded to SNS, the operator can check the information. Next, the information transmitted by the shovel controller 30 will be described.

[0168] For example, in the modified example 3 described above, the shovel controller 30 may transmit at least one of the charging conditions and warm-up conditions received from the management server to a mobile terminal used by the operator.

[0169] If the shovel controller 30 has charging start time information for starting battery charging or warm-up start time information for starting the warm-up of the hydraulic drive system set, the shovel controller 30 may transmit the charging start time information or the warm-up start time information for starting the warm-up of the hydraulic drive system to an external device (for example, a portable terminal used by the operator).

[0170] Furthermore, the shovel controller 30 may transmit schedule information (an example of first scheduled information) to an external device indicating whether or not there is a scheduled charge of the battery 192. For example, a scheduled charge of the battery 192 may occur if the work start time information is stored in the set time holding unit 305, or if charging conditions have been set.

[0171] Furthermore, the shovel controller 30 may transmit schedule information (an example of second schedule information) to an external device indicating whether or not there is a plan to warm up the hydraulic drive system. For example, a plan to warm up the hydraulic drive system may be in place if the work start time information is stored in the set time holding unit 305, or if warm-up conditions have been set.

[0172] Furthermore, when charging of the battery 192 is initiated from a power supply station (an example of an external power source), the shovel controller 30 may transmit charging status information indicating that the battery 192 is being charged to an external device (for example, a portable terminal used by the operator). The charging status information may include, for example, information indicating whether charging is currently taking place, the current state of charge (SOC) of the battery 192, or the predicted time when the battery 192 will be fully charged.

[0173] Furthermore, when the warm-up of the hydraulic drive system is initiated, the excavator controller 30 may transmit warm-up status information indicating that the warm-up of the hydraulic drive system is taking place to an external device (for example, a portable terminal used by the operator). The warm-up status information may include, for example, information indicating whether or not warm-up is taking place, the current temperature of the hydraulic fluid in the hydraulic drive system, and the predicted time until the hydraulic fluid reaches the target hydraulic fluid temperature.

[0174] In this modified example, the shovel controller 30 of the shovel 200 transmits various information to external devices. This allows the operator to recognize the charging and warming status of the shovel 200 even when the operator is not on board.

[0175] <effect> In the above-described embodiment, the shovel 200 can warm up the working oil in the hydraulic drive system using electricity supplied from an external power source (e.g., a refueling station), thereby reducing the power consumption of the battery 192. This reduces the reduction in working time due to warm-up operation and improves work efficiency.

[0176] In the embodiment described above, the battery 192 is charged while the hydraulic drive system's working oil is warmed up. Therefore, when the battery 192 is charged and the hydraulic drive system's working oil is warmed up, the shovel 200 is in an appropriate state to start work, thus further improving work efficiency.

[0177] In the above-described embodiment, by warming up the hydraulic drive system's working oil from a time obtained by subtracting the warm-up time from the start of work, the warm-up is completed by the start of work, allowing the shovel 200 to start work immediately. This improves work efficiency.

[0178] In the above-described embodiment, when warming up the hydraulic drive system's working oil, the Shovel 200 is electrically operated, so there is no need to start the engine. This makes warm-up control easy even when the operator is absent, thus improving safety and work efficiency.

[0179] Furthermore, since power supplied from battery 192 is not used during warm-up, the number of discharge and charge cycles of battery 192 can be reduced, thereby extending the battery's lifespan.

[0180] Although embodiments have been described in detail above, this disclosure is not limited to these specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims. [Explanation of symbols]

[0181] 200 Shovel 1. Lower running body 2. Swivel mechanism 3. Upper rotating body 4 Boom 5 Arms 6 buckets 7 Boom Cylinder 8 Arm Cylinder 9 Bucket Cylinder 10 cabins 12 Electric motors for pumps 14 Main pump 14a regulator 14b Temperature sensor 19 Battery Modules 191 Battery Controller 192 batteries 29A Discharge pressure sensor 30 Shovel Controller 50L, 50R relief valve 91 Communication equipment 92 Outdoor temperature sensor 301 Acquisition Department 302 Charging Control Unit 303 Settings Section 304 Warm-up control unit 305 Setting time holding section 306 Ability information storage unit 307 Warm-up time retention unit

Claims

1. Battery and An electric motor powered by electricity supplied from the aforementioned battery, The system includes a hydraulic drive system that drives a work attachment with power from the aforementioned electric motor, and is configured to warm up the hydraulic drive system with power supplied from the external power source when an external power source is connected to the battery in a rechargeable manner. The time information is stored in the memory unit. The warm-up time is calculated based on the amount of power supplied to the electric motor, the ambient temperature detected by the first detection unit, and the temperature of the hydraulic fluid detected by the second detection unit. By the time indicated in the aforementioned time information, the battery will be fully charged, The system is configured to start control to operate the electric motor with power supplied from the external power source to warm up the hydraulic drive system from a time obtained by subtracting the warm-up time from the time indicated by the time information, and to complete the warm-up of the hydraulic drive system when the temperature of the hydraulic fluid contained in the hydraulic drive system reaches or exceeds a predetermined value by the time indicated by the time information. Electric excavator.

2. When the external power supply is connected to the battery in a rechargeable manner, the system is configured to charge the battery with power supplied from the external power supply while simultaneously warming up the hydraulic drive system with power supplied from the external power supply. The electric excavator according to claim 1.

3. A battery and An electric motor powered by electricity supplied from the aforementioned battery, It has a hydraulic drive system that drives a work attachment with power from the aforementioned electric motor, When an external power source is connected to the battery in a rechargeable manner, the system is configured to charge the battery with power supplied from the external power source while simultaneously operating the electric motor with power supplied from the external power source to warm up the hydraulic drive system. The time information is stored in the memory unit. At the time indicated by the aforementioned time information, the hydraulic drive system is warmed up so that the temperature of the hydraulic fluid contained in the hydraulic drive system is maintained within a predetermined temperature range. Electric excavator.

4. The aforementioned time information is information received as operation information from an external device, information automatically set according to the schedule information of the electric excavator, or information based on the time when the electric excavator previously started work. The electric excavator according to claim 1 or 3.

5. The configuration is configured to suppress the warm-up of the hydraulic drive system when the external power supply is not connected to the battery in a way that allows it to charge. An electric shovel according to any one of claims 1 to 4.

6. If the external power supply is not connected to the battery in a way that allows it to be charged, then the predetermined conditions are met. When this happens, the system is configured to use the power supplied from the battery to warm up the hydraulic drive system. It is being done, The electric excavator according to claim 5.

7. It further includes a communication device that communicates with an external device, When the external power supply is connected to the battery in a rechargeable manner, the system is configured to receive from the external device using the communication device the charging conditions for charging the battery with power supplied from the external power supply, or the warm-up conditions for warming up the hydraulic drive system with power supplied from the external power supply. When the external power supply is rechargeably connected to the battery, the system is configured to charge the battery based on the charging conditions, or to warm up the hydraulic drive system based on the warm-up conditions. An electric shovel according to any one of claims 1 to 6.

8. A first notification information indicating the start of charging due to the fulfillment of the aforementioned charging conditions, or a second notification information indicating the start of warming up due to the fulfillment of the aforementioned warming-up conditions, is transmitted to the external device. The external device receives first permission information, which determines whether or not to permit the start of charging corresponding to the first notification information, or second permission information, which determines whether or not to permit the start of warming up corresponding to the second notification information. To start charging the battery in accordance with the first authorization information, or to start warming up the hydraulic drive system in accordance with the second authorization information, The electric shovel according to claim 7.

9. It further includes a communication device that communicates with an external device, The system is configured to transmit at least one of the following using the communication device: charging conditions for charging the battery with power supplied from the external power source or warming conditions for warming up the hydraulic drive system; charging start time information for starting to charge the battery or warming start time information for starting to warm up the hydraulic drive system; first scheduled information indicating whether or not charging the battery is scheduled to take place or second scheduled information indicating whether or not warming up the hydraulic drive system is scheduled to take place; and charging status information indicating that charging of the battery is taking place or warming status information indicating that warming up the hydraulic drive system is taking place. An electric shovel according to any one of claims 1 to 6.

10. A battery and An electric motor powered by electricity supplied from the aforementioned battery, It has a hydraulic drive system that drives a work attachment with power from the aforementioned electric motor, When an external power source is connected to the battery in a rechargeable manner, the hydraulic drive system is configured to be warmed up with power supplied from the external power source. The system is configured to suppress the warm-up of the hydraulic drive system when the external power supply is not connected to the battery in a rechargeable manner. When the external power source is not connected to the battery in a rechargeable manner, the system is configured to warm up the hydraulic drive system with power supplied from the battery when predetermined conditions are met. Electric excavator.

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