JP7445473B2 - excavator - Google Patents

Description

The present disclosure relates to excavators.

Conventionally, excavators are sometimes equipped with a power source that supplies power to a plurality of electrical loads (see Patent Documents 1 and 2).

JP2019-65567A Patent No. 4769670

However, depending on the operating status of multiple electrical loads, the energy efficiency of the power source may decrease.

Therefore, in view of the above problems, it is an object of the present invention to provide a technique that can suppress a decrease in energy efficiency of a power source installed in an excavator.

To achieve the above object, in one embodiment of the present disclosure,
power supply and
a plurality of electrical loads that operate with power supplied from the power source,
The maximum value of the current that the power supply can output is smaller than the maximum value of the current required to operate the plurality of electrical loads,
If the current required for the plurality of electrical loads is relatively large, restricting the operation of some of the electrical loads,
The some electrical loads include cooling system equipment that cools predetermined heat source equipment,
prompting an operator to restrict the use of at least some of the plurality of electrical loads when the temperature of the heat source equipment becomes relatively high while the operation of the cooling system equipment is restricted;
A shovel will be provided.
Additionally, in other embodiments of the present disclosure,
power supply and
a plurality of electrical loads that operate with power supplied from the power source,
The maximum value of the current that the power supply can output is smaller than the maximum value of the current required to operate the plurality of electrical loads,
If the current required for the plurality of electrical loads is relatively large, restricting the operation of some of the electrical loads,
The some electrical loads include cooling system equipment that cools predetermined heat source equipment,
The cooling system equipment includes a cooling fan that blows air to a heat exchanger that performs heat exchange between the refrigerant flowing inside and outside air, and a cooling fan that blows air to a heat exchanger that exchanges heat between the refrigerant flowing inside and outside air, and a cooling circuit that supplies the refrigerant with the heat source equipment and the heat exchanger. and a refrigerant pump that circulates the refrigerant.
When the current required for the plurality of electrical loads is relatively large, preferentially limiting the operation of the cooling fan of the cooling fan and the refrigerant pump;
A shovel will be provided.

According to the embodiments described above, it is possible to provide a technique that can suppress a decrease in energy efficiency of a power source mounted on an excavator.

It is a side view of an excavator. FIG. 1 is a block diagram schematically showing an example of the configuration of a shovel. It is a figure showing an example of the cooling circuit of an electric drive system. It is a diagram showing an example of a low voltage power supply system. 2 is a flowchart schematically showing a first example of control processing regarding a low-voltage power supply system of the control device. It is a flowchart which shows roughly the 2nd example of the control process regarding the low-voltage power supply system of a control apparatus. 12 is a flowchart schematically showing a third example of control processing regarding the low voltage power supply system of the control device. 12 is a flowchart schematically showing a third example of control processing regarding the low voltage power supply system of the control device. FIG. 7 is a diagram showing a specific example of the relationship between the total required current and the frequency of occurrence.

Embodiments will be described below with reference to the drawings.

[Excavator overview]
First, with reference to FIG. 1, an overview of a shovel 200 as an example of a working machine will be described.

FIG. 1 is a side view showing an example of a shovel 200 according to the present embodiment.

The excavator 200 according to the present embodiment includes an undercarriage body 1, an upper revolving body 3 that is rotatably mounted on the undercarriage body 1 via a rotation mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments. and a cabin 10.

The lower traveling body 1 includes, for example, a pair of left and right crawlers, and each crawler is hydraulically driven by travel hydraulic motors 1A and 1B (see FIG. 2), so that it travels by itself.

The upper rotating body 3 is electrically driven by a rotating electric motor 21 (see FIG. 2) through the rotating mechanism 2 to rotate relative to the lower traveling body 1. Further, the upper rotating body 3 may be hydraulically driven by a swing hydraulic motor through the swing mechanism 2 instead of the swing electric motor 21. In this case, in the excavator 200 of the present embodiment, all driven elements are hydraulically driven by hydraulic oil supplied from the main pump 14 (see FIG. 2) whose power source is an engine, and the so-called power source of a hydraulic excavator (engine ) is replaced with the pump electric motor 12.

The boom 4 is attached to the center of the front part of the upper revolving body 3 so that it can be lifted up and down, an arm 5 is attached to the tip of the boom 4 so that it can move up and down, and a bucket 6 is attached to the tip of the arm 5 so that it can be moved up and down. Can be installed. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9 as hydraulic actuators, respectively.

The bucket 6 is an example of an end attachment, and other end attachments may be attached to the tip of the arm 5 instead of the bucket 6 depending on the content of the work. The other end attachment may be a different type of bucket from the bucket 6, such as a slope bucket or a dredging bucket. Further, the other end attachment may be a different type of end attachment from the bucket, such as a breaker, an agitator, or a grapple.

The cabin 10 is mounted on the front left side of the upper revolving structure 3, and inside thereof (indoor) there is provided a cockpit where an operator is seated, an operating device 26, which will be described later, and the like.

The excavator 200 operates driven elements such as the lower traveling body 1 (left and right crawlers), the upper rotating body 3, the boom 4, the arm 5, and the bucket 6 in response to operations by an operator riding in the cabin 10.

Further, instead of being configured to be operable by an operator riding in the cabin 10, or in addition, the shovel 200 may be configured to be remotely operated from outside the shovel 200. When the excavator 200 is remotely controlled, the interior of the cabin 10 may be unmanned. The following description will proceed on the premise that the operator's operations include at least one of an operator's operation on the operating device 26 by an operator in the cabin 10 and a remote control by an external operator.

The remote control includes, for example, a mode in which the shovel 200 is operated by an operation input regarding an actuator of the shovel 200 performed by a predetermined external device. In this case, the excavator 200 is equipped with a communication device capable of communicating with a predetermined external device, and transmits, for example, image information (captured image) output by an imaging device included in the surrounding information acquisition device 40, which will be described later, to the external device. It's fine. Then, the external device may display the received image information (captured image) on a display device (hereinafter referred to as a "remote control display device") provided in the external device. Further, various information images (information screens) displayed on the output device 50 (display device) inside the cabin 10 of the excavator 200 may be similarly displayed on a remote control display device of an external device. As a result, the operator of the external device can, for example, remotely operate the shovel 200 while checking the display contents such as a captured image showing the surroundings of the shovel 200 or an information screen displayed on the remote control display device. can. Then, the excavator 200 operates the hydraulic actuator in response to a remote control signal that is received from an external device through the communication device and represents the content of the remote control, and operates the lower traveling structure 1 (left and right crawlers), the upper rotating structure 3, Driven elements such as boom 4, arm 5, and bucket 6 may be driven.

Further, the remote control may include, for example, a mode in which the shovel 200 is operated by external voice input or gesture input to the shovel 200 by a person (for example, a worker) around the shovel 200. Specifically, the excavator 200 receives sounds uttered by surrounding workers etc. through an audio input device (for example, a microphone) or a gesture input device (for example, an imaging device) mounted on the excavator 200 (its own machine). Recognize gestures, etc. performed by employees, workers, etc. Then, the excavator 200 operates the actuator according to the content of the recognized voice, gesture, etc., and moves the undercarriage 1 (left and right crawlers), the upper revolving structure 3, the boom 4, the arm 5, the bucket 6, etc. The drive element may also be driven.

Furthermore, the excavator 200 may automatically operate the actuator regardless of the details of the operator's operation. As a result, the excavator 200 has a function (so-called " ``Autonomous driving function'' or ``machine control function'').

The automatic operation function includes a function that automatically operates driven elements (actuators) other than the driven element (hydraulic actuator) to be operated in response to the operator's operation on the operating device 26 or remote control (so-called "semi-automatic operation function"). ”) may be included. In addition, the automatic operation function includes a function that automatically operates at least a part of a plurality of driven elements (actuators) on the premise that there is no operator operation on the operating device 26 or remote control (so-called "fully automatic operation function"). may be included. In the excavator 200, when the fully automatic driving function is enabled, the interior of the cabin 10 may be unmanned. Further, the semi-automatic driving function, fully automatic driving function, etc. may include a mode in which the operation details of a driven element (actuator) that is a target of automatic driving are automatically determined according to predefined rules. In addition, for the semi-automatic driving function and fully automatic driving function, the excavator 200 autonomously makes various judgments, and based on the judgment results, autonomously determines the operation of the driven element (actuator) that is the target of automatic driving. (so-called "autonomous driving function") may be included.

[Shovel configuration]
Next, the configuration of the shovel 200 according to the present embodiment will be described with reference to FIGS. 2 to 4 in addition to FIG. 1.

FIG. 2 is a block diagram schematically showing an example of the configuration of the shovel 200 according to the present embodiment. FIG. 3 is a diagram showing an example of the cooling circuit 60 of the electric drive system mounted on the excavator 200 according to the present embodiment. FIG. 4 is a diagram showing an example of a low voltage power supply system mounted on the excavator 200 according to the present embodiment.

In the figure, mechanical power lines are shown as double lines, high pressure hydraulic lines are shown as thick solid lines, pilot lines are shown as broken lines, and electric drive/control lines are shown as thin solid lines.

<Hydraulic drive system>
The hydraulic drive system of the excavator 200 according to the present embodiment includes traveling hydraulic motors 1A and 1B, a boom cylinder 7, and an arm that hydraulically drive driven elements such as a lower traveling body 1, a boom 4, an arm 5, and a bucket 6. It includes hydraulic actuators such as a cylinder 8 and a bucket cylinder 9. Further, the hydraulic drive system of the excavator 200 according to the present embodiment includes a pump electric motor 12, a main pump 14, and a control valve 17.

The pump electric motor 12 (an example of an electric actuator) is a power source for a hydraulic drive system. The pump electric motor 12 is, for example, an IPM (Interior Permanent Magnet) motor. The pump electric motor 12 is connected to a high-voltage power source including a power storage device 19 and a power conversion device 100 and a swing electric motor 21 via an inverter 18A. The pump electric motor 12 is powered by three-phase AC power supplied from the power storage device 19 and the swing electric motor 21 via the inverter 18A, and drives the main pump 14 and the pilot pump 15. Drive control of the pump electric motor 12 may be performed by an inverter 18A under the control of a controller 30B, which will be described later.

The main pump 14 supplies hydraulic oil to the control valve 17 through the high-pressure hydraulic line 16 by sucking hydraulic oil from the hydraulic oil tank T and discharging it to the high-pressure hydraulic line 16 . The main pump 14 is driven by the pump electric motor 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and a regulator (not shown) controls the angle (tilt angle) of the swash plate under the control of a controller 30A, which will be described later. Thereby, the main pump 14 can adjust the stroke length of the piston and adjust the discharge flow rate (discharge pressure).

Note that the main pump 14 may be driven by power from another power source in addition to the pump electric motor 12. For example, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 into the hydraulic oil tank is regenerated by the weight of the boom 4 or arm 5, and the main pump 14 is activated. It may be driven. Specifically, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic oil discharged from the boom cylinder 7 and arm cylinder 8 into the hydraulic oil tank due to the weight of the boom 4 and arm 5 is used to increase the main pump 14. A hydraulic motor disposed coaxially with the rotation axis of the motor may be driven. Also, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic oil discharged from the boom cylinder 7 and arm cylinder 8 into the hydraulic oil tank is regenerated by the weight of the boom 4 and arm 5, and the energy is used to generate electricity in the generator. may be performed. Specifically, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic oil discharged from the boom cylinder 7 and arm cylinder 8 into the hydraulic oil tank due to the weight of the boom 4 and arm 5 is used to generate electricity and power from the generator. The generator may generate electricity by driving a coaxially arranged hydraulic motor. In this case, the power generated by the generator may be supplied to the pump motor 12 or charged to the power storage device 19.

The control valve 17 is a hydraulic control device that controls the hydraulic drive system in response to an operator's operation or an operation command corresponding to an automatic driving function. As described above, the control valve 17 is connected to the main pump 14 via the high-pressure hydraulic line 16, and supplies the hydraulic oil supplied from the main pump 14 to the hydraulic actuators (travel hydraulic motors 1A, 1B, boom cylinder 7, arm cylinder 8 and bucket cylinder 9). For example, the control valve 17 is a valve unit that includes a plurality of control valves (direction switching valves) that control the flow rate and flow direction of the hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators. Hydraulic oil supplied from the main pump 14 and passed through the control valve 17 and the hydraulic actuator is discharged from the control valve 17 to the hydraulic oil tank T.

<Electric drive system>
The electric drive system of excavator 200 according to this embodiment includes a pump electric motor 12, a sensor 12s, and an inverter 18A. Further, the electric drive system of the excavator 200 according to the present embodiment includes a swing drive device 20, a sensor 21s, and an inverter 18B. Further, the electric drive system of the excavator 200 according to the present embodiment includes a high-voltage power source configured by a power storage device 19, a power conversion device 100, and the like.

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

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

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

The rotation state sensor 12s3 detects the rotation state (eg, rotation position (rotation angle), rotation speed, etc.) of the pump electric motor 12. The rotation state sensor 12s3 is, for example, a rotary encoder or a resolver.

The inverter 18A drives and controls the pump motor 12 under the control of the controller 30B. The inverter 18A defines, for example, a conversion circuit that converts DC power into three-phase AC power or converts three-phase AC power into DC power, a drive circuit that drives a switch of the conversion circuit, and the operation of the drive circuit. and a control circuit that outputs a control signal (for example, a PWM (Pulse Width Modulation) signal).

The control circuit of the inverter 18A controls the drive of the pump motor 12 while grasping the operating state of the pump motor 12. For example, the control circuit of the inverter 18A grasps the operating state of the pump motor 12 based on the detection signal of the rotation state sensor 12s3. In addition, the control circuit of the inverter 18A sequentially controls 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 in the control process). By estimating, the operating state of the pump motor 12 may be grasped.

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

The swing drive device 20 includes a swing electric motor 21 , a resolver 22 , a mechanical brake 23 , and a swing reduction gear 24 .

The swing electric motor 21 (an example of an electric actuator) is operated under the control of the controller 30B and the inverter 18B for a power running operation in which the upper rotating structure 3 is driven to swing, and a regenerative operation in which regenerative power is generated to swing and brake the upper rotating structure 3. I do. The swing electric motor 21 is connected to a high-voltage power source (that is, the power storage device 19 and the power conversion device 100, etc.) via an inverter 18B, and is driven by three-phase AC power supplied from the power storage device 19 via the inverter 18B. . Further, the swing electric motor 21 supplies regenerated power to the power storage device 19 and the pump electric motor 12 via the inverter 18B. Thereby, the power storage device 19 can be charged or the pump electric motor 12 can be driven with the regenerated power. Switching control between the power running operation and the regenerative operation of the turning electric motor 21 may be performed by the inverter 18B under the control of the controller 30B, for example. A resolver 22, a mechanical brake 23, and a swing speed reducer 24 are connected to the rotating shaft 21A of the swing electric motor 21.

The resolver 22 detects the rotational state (for example, rotational position (rotation angle), rotational speed, etc.) of the turning electric motor 21. A detection signal corresponding to the rotation angle etc. detected by the resolver 22 may be directly taken into the inverter 18B through a communication line. Further, the detection signal may be taken into the controller 30B through the communication line and input to the inverter 18B via the controller 30B.

The mechanical brake 23 mechanically generates a braking force on the rotating shaft 21A of the turning electric motor 21 under the control of the controller 30B. Thereby, the mechanical brake 23 can perform swing braking of the revolving upper structure 3 and maintain the stopped state of the revolving upper structure 3.

The swing reducer 24 is connected to the rotating shaft 21A of the swing electric motor 21, and reduces the output (torque) of the swing electric motor 21 at a predetermined reduction ratio to increase the torque and rotate the upper swing structure 3. drive That is, during power running, the swing electric motor 21 drives the upper rotating body 3 to swing via the swing reduction gear 24 . Moreover, the swing reducer 24 increases the speed of the inertial rotational force of the upper swing structure 3 and transmits it to the swing electric motor 21, thereby generating regenerative power. That is, during regenerative operation, the swing electric motor 21 performs regenerative power generation using the inertial rotational force of the upper revolving structure 3 transmitted via the swing reducer 24, and swing-brakes the upper revolving structure 3.

The sensor 21s includes a current sensor 21s1 and a voltage sensor 21s2.

The current sensor 21s1 detects the current of each of the three phases (U phase, V phase, and W phase) of the turning electric motor 21. The current sensor 21s1 is provided, for example, in a power path between the swing electric motor 21 and the inverter 18B. Detection signals corresponding to the currents of each of the three phases of the swing electric motor 21 detected by the current sensor 21s1 may be directly taken into the inverter 18B through the communication line. Further, the detection signal may be taken into the controller 30B through the communication line and input to the inverter 18B via the controller 30B.

The voltage sensor 21s2 detects the voltage applied to each of the three phases of the turning electric motor 21. The voltage sensor 21s2 is provided, for example, in a power path between the swing electric motor 21 and the inverter 18B. Detection signals corresponding to the voltages applied to each of the three phases of the swing electric motor 21 detected by the voltage sensor 21s2 are directly taken into the inverter 18B through the communication line. Further, the detection signal may be taken into the controller 30B through the communication line and input to the inverter 18B via the controller 30B.

The inverter 18B drives and controls the turning electric motor 21 under the control of the controller 30B. The inverter 18B defines, for example, a conversion circuit that converts DC power into three-phase AC power or converts three-phase AC power into DC power, a drive circuit that drives a switch of the conversion circuit, and the operation of the drive circuit. and a control circuit that outputs a control signal (for example, a PWM signal).

For example, the control circuit of the inverter 18B performs speed feedback control and torque feedback control regarding the turning electric motor 21 based on the detection signals of the current sensor 21s1, the voltage sensor 21s2, and the resolver 22.

For example, as shown in FIG. 3, inverters 18A and 18B may be housed in one housing, and may integrally constitute inverter unit 18.

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

The power storage device 19 is charged (stored) by being connected to an external commercial power source through a predetermined cable (hereinafter referred to as a "charging cable"). An on-vehicle charger may be provided in the power path between the power storage device 19 and the charging port to which the charging cable is connected. The on-vehicle charger converts AC power supplied from an external commercial power source to DC power of a predetermined voltage through a charging cable, for example, and charges the power storage device 19.

Furthermore, the power storage device 19 supplies the charged (stored) power to the pump electric motor 12 and the swing electric motor 21 . Further, the power storage device 19 charges the electric power generated by the turning electric motor 21 (regenerated electric power).

Power storage device 19 is, for example, a lithium ion battery and has a relatively high output voltage (for example, several hundred volts).

The power conversion device 100 boosts the power of the power storage device 19 or steps down the power from the pump electric motor 12 and the swing electric motor 21 via inverters 18A and 18B, and causes the power storage device 19 to store the power. The power converter 100 switches between boost operation and step-down operation according to the operating states of the pump electric motor 12 and the swing electric motor 21 so that the voltage value of the DC (Direct Current) bus 110 falls within a certain range. Switching control between the voltage step-up operation and the voltage step-down operation of the power conversion device 100 is executed by the controller 30B based on, for example, the voltage detection value of the DC bus 110, the voltage detection value of the power storage device 19, and the current detection value of the power storage device 19. It's fine.

Note that if there is no need to boost the output voltage of the power storage device 19 and apply it to the pump electric motor 12 or the swing electric motor 21, the power converter 100 may be omitted.

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

Pilot pump 15 supplies pilot pressure to various hydraulic devices (for example, pressure control valve 31) mounted on excavator 200 via pilot line 25. Thereby, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the operation details (eg, operation amount and operation direction) of the operating device 26 under the control of the controller 30A. Therefore, the controller 30A and the pressure control valve 31 can realize the operation of the driven element (hydraulic actuator) according to the operator's operation on the operating device 26. Moreover, the pressure control valve 31 can supply a pilot pressure to the control valve 17 according to the details of the remote control specified by the remote control signal under the control of the controller 30A. The pilot pump 15 is, for example, a fixed capacity hydraulic pump, and is driven by the pump electric motor 12 as described above.

The operating device 26 is provided within the reach of the operator in the cockpit of the cabin 10, and allows the operator to control the respective driven elements (i.e., the left and right crawlers of the undercarriage 1, the upper revolving structure 3, the boom 4, and the arm 5). , bucket 6, etc.). In other words, the operating device 26 is a hydraulic actuator (for example, travel hydraulic motors 1A, 1B, boom cylinder 7, arm cylinder 8, bucket cylinder 9, etc.) or an electric actuator (swinging hydraulic actuator) with which an operator drives each driven element. It is used to operate the electric motor 21, etc.). The operating device 26 is, for example, an electric type, and outputs an electrical signal (hereinafter referred to as an "operating signal") according to the content of an operation by an operator. The operation signal output from the operation device 26 is taken into the controller 30A. As a result, the control device 30 including the controller 30A controls the pressure control valve 31 and the inverter 18B, and controls the driven elements (actuators) of the excavator 200 according to the operator's operation details and operation commands corresponding to the automatic operation function. can control the operation of

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

In addition, when the control valve 17 is composed of an electromagnetic pilot type control valve (directional switching valve), the operation signal of the electric operating device 26 is directly input to the control valve 17, and each hydraulic control valve is configured as an operating device. 26 may be adopted. Further, the operating device 26 may be of a hydraulic pilot type that outputs a pilot pressure depending on the content of the operation. In this case, pilot pressure depending on the operation content is supplied to the control valve 17.

The pressure control valve 31 outputs a predetermined pilot pressure using hydraulic oil supplied from the pilot pump 15 through the pilot line 25 under the control of the controller 30A. A 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 .

<Control system>
The control system of excavator 200 according to this embodiment includes a control device 30, a surrounding information acquisition device 40, an output device 50, and an input device 52.

Control device 30 includes controllers 30A to 30C.

The respective functions of the controllers 30A to 30C may be realized by arbitrary hardware or a combination of arbitrary hardware and software. For example, the controllers 30A to 30C each include a processor such as a CPU (Central Processing Unit), a memory device (main storage device) such as a RAM (Random Access Memory), and a nonvolatile auxiliary storage device such as a ROM (Read Only Memory). , and an interface device for external input/output.

The controller 30A performs drive control of the shovel 200 in cooperation with various controllers that constitute the control device 30 including the controllers 30B and 30C.

For example, the controller 30A outputs a control command to the pressure control valve 31 in response to an operation signal input from the operating device 26, and causes the pressure control valve 31 to output a pilot pressure according to the operation details of the operating device 26. Thereby, the controller 30A can realize the operation of the driven element (hydraulic actuator) of the shovel 200 corresponding to the operation content of the electric operating device 26.

Further, when the excavator 200 is remotely operated, the controller 30A may perform control related to the remote operation, for example. Specifically, the controller 30A may output a control command to the pressure control valve 31, and cause the pressure control valve 31 to output a pilot pressure according to the content of the remote control. Thereby, the controller 30A can realize the operation of the shovel 200 (driven element) corresponding to the content of the remote control.

Further, the controller 30A may perform control related to automatic driving functions, for example. Specifically, the controller 30A may output a control command to the pressure control valve 31, and cause the pressure control valve 31 to act on the control valve 17 with a pilot pressure according to the operation command corresponding to the automatic operation function. Thereby, the controller 30A can realize the operation of the driven element (hydraulic actuator) of the excavator 200 that corresponds to the automatic operation function.

Further, the controller 30A may control, for example, the operation and stop of the cooling fan 66.

Further, the controller 30A may integrally control the operation of the entire shovel 200 (various devices mounted on the shovel 200) based on bidirectional communication with various controllers such as the controllers 30B and 30C, for example.

The controller 30B performs drive control of the electric drive system based on various information input from the controller 30A (for example, control commands including operation signals of the operating device 26, etc.).

The controller 30B may, for example, drive the inverter 18B based on the operation details of the operating device 26, and perform switching control of the operating state (power running operation and regenerative operation) of the turning electric motor 21. Further, for example, when the excavator 200 is remotely controlled, the controller 30B drives the inverter 18B and controls the switching of the operating state (power running mode and regenerative mode) of the swing electric motor 21 based on the content of the remote control. good. Further, for example, when the automatic operation function of the excavator 200 is enabled, the controller 30B drives the inverter 18B based on the operation command corresponding to the automatic operation function, and controls the operating state of the swing electric motor 21 (power running operation and regenerative operation). Switching control may be performed.

Further, the controller 30B drives the power converter 100 based on the operating state of the operating device 26, for example, and controls the voltage step-up operation and step-down operation of the power converter 100, in other words, the discharge state and charging state of the power storage device 19. Switching control may be performed. Further, for example, when the excavator 200 is remotely controlled, the controller 30B may drive the power conversion device 100 and control switching between the discharging state and the charging state of the power storage device 19 based on the content of the remote control. Further, for example, when the automatic operation function of the excavator 200 is enabled, the controller 30B drives the power conversion device 100 based on the operation command corresponding to the automatic operation function, and switches the power storage device 19 between the discharging state and the charging state. Control may be performed.

The controller 30C controls the surroundings monitoring function of the excavator 200.

For example, the controller 30C controls the surroundings of the excavator 200 based on information regarding the situation of the three-dimensional space around the excavator 200 (for example, detection information regarding objects around the excavator 200 and their positions), which is acquired from the surrounding information acquisition device 40. Detect predetermined objects and their positions (hereinafter referred to as "monitoring targets").

Further, when the controller 30C detects a monitoring target in a region relatively close to the excavator 200, for example, the controller 30C outputs an alarm through the output device 50 (for example, a display device, a sound output device, etc.) inside the cabin 10. It's fine.

Note that the functions of the controllers 30B and 30C may be integrated into the controller 30A. That is, the various functions realized by the control device 30 may be realized by one controller, or may be realized in a distributed manner by two or more controllers set as appropriate.

The surrounding information acquisition device 40 outputs information regarding the situation of the three-dimensional space around the excavator 200. The surrounding information acquisition device 40 may include, for example, an ultrasonic sensor, a millimeter wave radar, a monocular camera, a stereo camera, a depth camera, a LIDAR (Light Detection and Ranging), a distance image sensor, an infrared sensor, and the like. The output information of the surrounding information acquisition device 40 is taken into the controller 30C.

The output device 50 is provided in the cabin 10 and outputs various information to the operator under the control of the control device 30 (eg, controller 30A). 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 installed, for example, at a location within the cabin 10 that is easily visible to the operator, and may display various information images under the control of the controller 30A. The display device is, for example, a liquid crystal display or an organic EL (Electroluminescence) display. Further, the output device 50 includes, for example, a sound output device that outputs information to the operator in an auditory manner. The sound output device is, for example, a buzzer, a speaker, or the like.

The input device 52 is provided within the cabin 10 and receives various inputs from the operator. The input device 52 may include, for example, an operation input device that accepts an operation input from an operator. The operation input device includes, for example, a button, a toggle, a lever, a touch panel, a touch pad, and the like. Further, the input device 52 may include, for example, a voice input device that accepts voice input from an operator and a gesture input device that accepts gesture input from the operator. The voice input device includes, for example, a microphone that captures the voice of the operator inside the cabin 10. Further, the gesture input device includes, for example, an indoor camera that can capture an image of the operator's gesture inside the cabin 10. A signal corresponding to an input from the operator accepted by the input device 52 is taken into the control device 30 (eg, controller 30A).

<Cooling system>
The cooling system of excavator 200 of this embodiment includes a cooling circuit 60 and an oil cooler 70.

The cooling circuit 60 is provided, for example, in the upper revolving body 3 and cools electrically driven equipment (hereinafter referred to as "electrically driven equipment"). For example, as shown in FIG. 3, electrically driven devices (an example of heat source devices) to be cooled by the cooling circuit 60 include a pump motor 12, an inverter unit 18, a power storage device 19, a swing drive device 20, and a power conversion device 100. etc. are included. Further, the electric drive equipment to be cooled by the cooling circuit 60 may include an on-vehicle charger. This is because the on-vehicle charger generates heat when charging the power storage device 19.

As shown in FIG. 3, the cooling circuit 60 includes a radiator 62, a water pump 64, a cooling fan 66, and refrigerant channels 68A, 68B, 68C, 68C1, 68C2, 68D, 68D1, 68D2, 68E, and 68F. include.

The radiator 62 (an example of a heat exchanger) cools the refrigerant (for example, cooling water) in the cooling circuit 60. Specifically, the radiator 62 cools the refrigerant by exchanging heat between the surrounding air and the refrigerant.

The water pump 64 (an example of a refrigerant pump) circulates the refrigerant in the cooling circuit 60 by sucking the refrigerant from the refrigerant flow path 68F and discharging it into the refrigerant flow path 68A.

The cooling fan 66 blows air to the radiator 62. Thereby, heat exchange in the radiator 62 is promoted, and the cooling efficiency of the radiator 62, that is, the degree of cooling of the radiator 62 can be improved. The number of cooling fans 66 may be one or more.

The refrigerant flow path 68A connects the water pump 64 and the swing drive device 20, and causes the refrigerant discharged from the water pump 64 to flow into the refrigerant flow path inside the swing drive device 20. Thereby, the swing electric motor 21 and the like in the swing drive device 20 can be cooled with the refrigerant. The refrigerant that has passed through the interior of the swing drive device 20 flows out into the refrigerant flow path 68B.

Refrigerant flow path 68B connects swing drive device 20 and power storage device 19, and causes the refrigerant flowing out from swing drive device 20 to flow into the coolant flow path inside power storage device 19. Thereby, power storage device 19 can be cooled with the refrigerant. The refrigerant that has passed through the interior of power storage device 19 flows out into refrigerant flow path 68C.

Refrigerant flow paths 68C, 68C1, and 68C2 connect the power storage device 19 and the inverter unit 18 and power conversion device 100, and connect the refrigerant flowing out from the power storage device 19 to the refrigerant inside the inverter unit 18 and the power conversion device 100. flow into the flow path. Specifically, the refrigerant flow path 68C whose one end is connected to the power storage device 19 branches into refrigerant flow paths 68C1 and 68C2 at the other end, and the refrigerant flow paths 68C and 68C2 are connected to the inverter unit 18 and the power converter, respectively. Connected to device 100. Thereby, inverters 18A, 18B included in inverter unit 18 and power converter 100 can be cooled. The refrigerant that has passed through the inside of the inverter unit 18 flows out into the refrigerant flow path 68D1. Further, the refrigerant that has passed through the inside of the power conversion device 100 flows out into the refrigerant flow path 68D2.

The refrigerant channels 68D, 68D1, and 68D2 connect the inverter unit 18 and the power converter 100 to the pump motor 12, and direct the refrigerant flowing out from the inverter unit 18 and the power converter 100 to the inside of the pump motor 12. Let it flow into the refrigerant flow path. Specifically, refrigerant flow paths 68D1 and 68D2, each of which has one end connected to the inverter unit 18 and the power converter 100, merge with one end of the refrigerant flow path 68D, and the other end of the refrigerant flow path 68D connects to the pump electric motor. 12. Thereby, the pump electric motor 12 can be cooled with the refrigerant. The refrigerant that has passed through the pump motor 12 flows out into the refrigerant flow path 68E.

The refrigerant flow path 68E connects between the pump motor 12 and the radiator 62, and supplies the refrigerant flowing out from the pump motor 12 to the radiator 62. Thereby, by cooling the various devices of the electric drive system, the refrigerant whose temperature has increased can be cooled by the radiator, and the various devices of the electric drive system can be returned to a state where they can be cooled again.

The refrigerant flow path 68F connects the radiator 62 and the water pump 64, and supplies the refrigerant cooled by the radiator 62 to the water pump 64. The water pump 64 can circulate the refrigerant cooled by the radiator 62 to the cooling circuit 60.

The oil cooler 70 is provided, for example, in the upper revolving structure 3 and cools the hydraulic oil of the hydraulic drive system. Specifically, the oil cooler 70 is provided, for example, in a return oil path between the control valve 17 and the hydraulic oil tank T, and exchanges heat between the surrounding air and the hydraulic oil flowing inside. , to cool the hydraulic fluid. The oil cooler 70 may be arranged in series with the radiator 62 with respect to the cooling fan 66, for example, and may be cooled by air blown from the cooling fan 66. Further, the oil cooler 70 is arranged separately (for example, in parallel) with the radiator 62 and the cooling fan 66, and is cooled by air from a cooling fan (hereinafter referred to as "oil cooler fan") that is different from the cooling fan 66. Good too. In this case, the number of oil cooler fans may be one or more.

Note that some or all of the plurality of electric drive system devices may be air-cooled. In this case, a cooling fan may be provided to blow air to the electric drive system equipment to be air-cooled. Furthermore, a dedicated cooling fan may be provided for one electric drive system device, or a shared cooling fan may be provided for a plurality of electric drive system devices.

<Low voltage power supply system>
As shown in FIG. 4, the low-voltage power supply system of the excavator 200 according to the present embodiment includes a low-voltage power supply 44 and a plurality of electrical loads that operate with power supplied from the low-voltage power supply 44.

The low voltage power supply 44 (an example of a power supply) supplies power to a plurality of electrical loads other than electrical drive system equipment that operates at very high voltage. Low voltage power supply 44 includes a DC-DC converter 44A and a battery 44B.

The DC-DC converter 44A (an example of a power conversion device) is provided, for example, in the upper revolving structure 3, and converts the very high voltage DC power output from the power storage device 19 to a predetermined voltage (for example, about 24 volts). Steps down and outputs. The output power of the DC-DC converter 44A is supplied to a plurality of electrical loads or charged to the battery 44B.

The battery 44B is provided, for example, in the upper revolving structure 3, and has a relatively low output voltage (for example, 24 volts). The battery 44B is, for example, a lead-acid battery or a lithium ion battery, and as described above, outputs power to a plurality of electrical loads or is charged with power generated by the DC-DC converter 44A.

Note that the low voltage power supply 44 may include a generator (for example, an alternator) in place of or in addition to the DC-DC converter 44A. In this case, the alternator may generate power using the power of the pump electric motor 12, or may generate power using the power of another electric motor that operates with power supplied from the power storage device 19, for example.

Each of the plurality of electrical loads operates with relatively low voltage power supplied from the low voltage power supply 44.

The plurality of electrical loads include, for example, cooling system equipment. The cooling system equipment includes a water pump 64 and a cooling fan 66. Further, when an oil cooler fan is provided, the cooling system equipment includes the oil cooler fan.

Further, the plurality of electrical loads include, for example, hydraulic drive system equipment. The hydraulic drive system equipment includes various solenoid actuators 17A built into the control valve 17.

Further, the plurality of electrical loads include, for example, operating equipment. The operating system equipment includes, for example, an operating device 26 and a pressure control valve 31.

Further, the plurality of electrical loads include, for example, control system equipment. The control system equipment includes, for example, controllers 30A to 30C and a surrounding information acquisition device 40.

Further, the plurality of electrical loads include, for example, user interface equipment. The user interface device includes, for example, an output device 50 and an input device 52.

Further, the plurality of electrical devices include, for example, comfort equipment devices. The comfort equipment includes, for example, an air conditioner 80. Furthermore, the comfort equipment may include, for example, a seat heater.

The air conditioner 80 adjusts the indoor temperature, humidity, etc. of the cabin 10. The air conditioner 80 may be, for example, a heat pump type including a heat pump cycle for both cooling and heating. Furthermore, the air conditioner 80 may include, for example, a refrigeration cycle for cooling and a heater for heating. The heater for space heating is, for example, a PTC (Positive Temperature Coefficient), a combustion type heater, or the like. The air conditioner 80 includes a compressor 82 that compresses refrigerant flowing through a heat pump cycle or a refrigeration cycle. The compressor 82 is driven by the power of the pump electric motor 12.

The seat heater is built into the seat or back of the cockpit of the cabin 10, and warms the operator seated from the cockpit side.

Further, the plurality of electrical loads may include, for example, communication equipment.

The communication device communicates with, for example, an external device of the excavator 200 or a device brought into the cabin 10 by the operator (for example, a mobile terminal such as a smartphone). The communication device includes, for example, a mobile communication module that communicates with an external device of excavator 200 using a mobile communication network that terminates at a base station. Further, the communication device includes a short-range communication module that communicates with devices inside the cabin 10 using a predetermined communication standard such as WiFi or Bluetooth (registered trademark).

Furthermore, the plurality of electrical loads include, for example, audio equipment. The audio equipment may include, for example, a radio receiver provided within the cabin 10.

Furthermore, the plurality of electrical loads include, for example, safety equipment equipment. The safety equipment may include, for example, a wiper.

The wiper is provided on the front window of the cabin 10 and wipes off water droplets from rain or the like adhering to the surface of the front window.

Further, the plurality of electrical loads include, for example, lighting equipment. The lighting equipment may include, for example, a headlamp.

The headlight is provided, for example, at the front end of the revolving upper structure 3 and illuminates the front of the revolving upper structure 3.

Among the multiple electrical loads to which the low-voltage power supply 44 supplies power, there are electrical loads that are always in operation and require a certain amount of current at all times, and electrical loads that can be started and stopped and require almost no current when stopped. There is also a load. Furthermore, among the multiple electrical loads to which the low-voltage power supply 44 supplies power, there are some electrical loads in which the required current hardly changes during operation, and there are electrical loads in which the required current changes relatively greatly during operation. . Therefore, depending on the operating status of each electrical load, the current required for all electrical loads to which the low-voltage power supply 44 supplies power, that is, the current required from each of all electrical loads (hereinafter referred to as "required current"). (hereinafter referred to as "required current total value") can vary within a certain range.

On the other hand, the maximum value of the current that the low-voltage power supply 44 can output (hereinafter referred to as "maximum output current") is the current required (total required current) according to the operating status of all electrical loads to which power is supplied. value) (hereinafter referred to as "maximum required current total value"). The maximum output current of the low voltage power supply 44 may be defined based on, for example, the maximum output current (rated current) of the DC-DC converter 44A. Specifically, the maximum output current of the low voltage power supply 44 may be set to be smaller than the sum of the rated currents of all the electrical loads to which power is supplied. If the low-voltage power supply 44 is configured to be able to output a current greater than the maximum total required current of all electrical loads, the low-voltage power supply 44 will be This is because energy efficiency may be relatively reduced (see FIG. 9 described later).

In addition, when the total required current value of all the electric loads to which the low-voltage power supply 44 supplies power is relatively large, the control device 30 controls the operation of some of the electric loads that have a relatively small influence on the operation of driven elements of the excavator 200. Operation of electrical loads may be restricted. The control device 30 may determine (estimate) the required current of each electrical load, for example, based on information regarding the operating status of each electrical load to which the low-voltage power supply 44 supplies power. The information regarding the operating status of the electrical load includes, for example, information regarding ON/OFF status of the electrical load, information regarding the contents of operator operations that determine the operating status of the electrical load, and input device 52 that determines the operating status of the electrical load. Contains information regarding the content of the input from. Thereby, the control device 30 can intentionally limit the operation of some electrical loads and lower the total required current value. Therefore, the control device 30 may, for example, cause the total required current of all electrical loads to exceed the maximum output current of the low-voltage power supply 44, and as a result, the hydraulic drive system equipment and operation system equipment of the excavator 200 may operate. It is possible to prevent situations that could affect the

For example, a priority regarding operation restriction (hereinafter referred to as “operation restriction priority”) may be predefined for each of all the electrical loads to which the low-voltage power supply 44 supplies power. Then, when the total required current value is relatively large, the control device 30 limits the operation of the electrical load with a relatively high operation restriction priority among all the electrical loads to which the low-voltage power supply 44 supplies power. It's fine. For example, the operation restriction priority of hydraulic drive system equipment, operation system equipment, and control system equipment among all the electrical loads to which the low-voltage power supply 44 supplies power may be set relatively low. This is because if the operation of hydraulic drive system equipment, operation system equipment, or control system equipment is restricted, the operation of the actuator of excavator 200 may be affected. Furthermore, the same may apply to communication equipment. On the other hand, the operation restriction priority of cooling system equipment may be set relatively high. This is because the heat capacity of the refrigerant included in the cooling circuit 60 is relatively large, and even if the operation of the cooling system equipment is temporarily restricted, the temperature of the electric drive system equipment is unlikely to rise suddenly. Further, the operation restriction priority of the air conditioner 80, comfort equipment such as a seat heater, and audio equipment may be set higher than hydraulic drive equipment and the like, and lower than cooling equipment. This is because although the operation of the driven elements of the shovel 200 is not affected, the operator inside the cabin 10 may be affected.

Details of the method for limiting the operation of some of the electrical loads to which the low-voltage power supply 44 supplies power will be described later (see FIGS. 5 to 8).

[Control processing related to low voltage power supply system]
Next, control processing regarding the low voltage power supply system by the control device 30 (controller 30A) will be described with reference to FIGS. 5 to 8. Hereinafter, it is assumed that the cooling system equipment (water pump 64 and cooling fan 66) etc. to which the low-voltage power supply 44 supplies power are always in operation.

<First example of control processing related to low voltage power supply system>
FIG. 5 is a flowchart schematically showing a first example of control processing regarding the low voltage power supply system of the control device 30 (controller 30A). This flowchart is executed, for example, at predetermined time intervals. The same may apply to the flowchart in FIG. 6 and the flowcharts in FIGS. 7 and 8 below.

As shown in FIG. 5, in step S102, the controller 30A determines whether the total required current value of all the electrical loads to which the low-voltage power supply 44 supplies power exceeds a threshold value Ith1. The threshold value Ith1 is, for example, an adaptive value set to be less than or equal to the maximum output current of the low voltage power supply 44. If the total requested current value exceeds the threshold value Ith1, the controller 30A proceeds to step S104, and if it does not exceed the threshold value Ith1, the controller 30A ends the process of the current flowchart.

In step S104, the controller 30A outputs a control command to the water pump 64 and cooling fan 66 in operation to limit their operations. The controller 30A may, for example, stop the water pump 64 and the cooling fan 66. Further, the controller 30A may, for example, operate at least one of the water pump 64 and the cooling fan 66 at a lower rotational speed than during normal operation, instead of stopping the water pump 64 and the cooling fan 66. Hereinafter, the same method may be used to limit the operation of the water pump 64 and the cooling fan 66 in the flowchart of FIG. 6 and the flowcharts of FIGS. 7 and 8. Thereby, the control device 30 can reduce the total required current value of all the electrical loads to which the low-voltage power supply 44 supplies power.

Furthermore, while the water pump 64 and the cooling fan 66 are being restricted, the controller 30A determines whether the operation is restricted according to how much the total required current exceeds the threshold value Ith1, assuming that there is no restriction on the operation. The degree may be varied. Specifically, the controller 30A may increase the degree of operation restriction as the amount by which the total required current exceeds the threshold value Ith1 assuming that there is no operation restriction. For example, if the amount by which the total required current value exceeds the threshold value Ith1 assuming that there are no operational restrictions is relatively small, the controller 30A controls the rotation speed of the water pump 64 and the cooling fan 66 to be higher than normal. Operate in low condition. Furthermore, the controller 30A may reduce the rotational speed of the water pump 64 and the cooling fan 66 as the amount by which the total required current value exceeds the threshold value Ith1 assuming that there are no operational restrictions increases. Then, the controller 30A may stop the water pump 64 and the cooling fan 66 when the amount by which the total required current value exceeds the threshold value Ith1, assuming that there are no operational restrictions, exceeds a predetermined threshold value. Further, for example, if the amount by which the total required current value exceeds the threshold value Ith1 assuming that there are no operational restrictions is relatively small, the controller 30A may cause some of the cooling fans 66 of the plurality of cooling fans 66 to Restrict operations. Further, the controller 30A controls the number of cooling fans 66 whose operation is restricted among the plurality of cooling fans 66 as the amount by which the total required current value exceeds the threshold value Ith1 when assuming that there is no operation restriction increases. may be increased. Then, the controller 30A may limit the operation of all the cooling fans 66 when the amount by which the total required current value exceeds the threshold value Ith1, assuming that there is no operation restriction, exceeds a predetermined threshold value. Hereinafter, the same method may be used to limit the operation of the water pump 64 and the cooling fan 66 in the flowchart of FIG. 6 and the flowcharts of FIGS. 7 and 8.

When the process of step S104 is completed, the controller 30A proceeds to step S106.

In step S106, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is equal to or less than a threshold value Ith2 (≦Ith1). The controller 30A proceeds to step S108 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith2, and proceeds to step S110 when it is not equal to or less than the threshold value Ith2.

In step S108, the controller 30A outputs a control command to the water pump 64 and the cooling fan 66 to release their operation restrictions.

When the process of step S108 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, in step S110, the controller 30A determines whether the temperature of at least one of all the electric drive system devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth11. The threshold value TDth11 is a suitable value defined in advance for each device to be cooled by the cooling circuit 60. The controller 30A can determine the temperature of all the electric drive system devices to be cooled in the cooling circuit 60 by taking in detection signals from temperature sensors installed in each of the electric drive system devices. If the temperature of at least one of the electric drive system devices to be cooled in the cooling circuit 60 exceeds the threshold value TDth11, the controller 30A proceeds to step S112 and determines that the temperature of all the electric drive system devices exceeds the threshold value TDth11. If not, the process returns to step S106.

In step S112, the controller 30A outputs a control command to a specific device other than the cooling system device (hereinafter referred to as "emergency restriction target device") among the electrical loads to which the low-voltage power supply 44 supplies power, and controls its operation. limit. Then, the controller 30A outputs a control command to the water pump 64 and the cooling fan 66, and releases the operational restrictions. Thereby, the control device 30 can suppress the temperature rise of the electric drive system equipment while continuing to suppress the total required current value of the electric loads to which the low-voltage power supply 44 supplies power. The emergency restriction target device may be, for example, an electric load that has a relatively high operation restriction priority among all the electric loads to which the low-voltage power supply 44 supplies power. Further, the emergency restriction target device is, for example, an electric load that has a relatively high operation restriction priority and a relatively high required current among all the electric loads to which the low-voltage power supply 44 supplies power. Good too. This is because the effect of reducing the total required current value due to operation restriction can be enhanced. Furthermore, among all the electric loads to which the low-voltage power supply 44 supplies power, the device subject to emergency restriction is, for example, an operator in the cabin 10, although the influence on the operation of the actuator of the excavator 200 is relatively small due to the operation restriction. It may also be an electrical load that can be affected.

When the process of step S112 is completed, the controller 30A proceeds to step S114.

In step S114, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is less than or equal to the threshold value Ith2. If the total required current value is equal to or less than the threshold value Ith2 assuming that there are no operational restrictions, the controller 30A determines that the total required current value is relatively low, and proceeds to step S116. On the other hand, if the total required current value assuming that there is no operational restriction is not less than the threshold Ith2, the controller 30A determines that the total required current value continues to be relatively high, and proceeds to step S118.

In step S116, the controller 30A outputs a control command to the device subject to emergency restriction and cancels its operation restriction. As a result, all operational restrictions in all electrical loads to which the low-voltage power supply 44 supplies power are released.

When the process of step S116 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, in step S118, the controller 30A determines whether the temperatures of all the electric drive system devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth21 (≦TDth11). If the temperature of all the electric drive system devices to be cooled by the cooling circuit 60 is below the threshold value TDth21, the controller 30A determines that the temperature of the electric drive system devices has decreased to some extent, and proceeds to step S120. On the other hand, if the temperature of all the electric drive system devices to be cooled by the cooling circuit 60 is not equal to or lower than the threshold value TDth21, the controller 30A determines that the temperature of the electric drive system devices remains relatively high, and returns to step S114. .

In step S120, the controller 30A outputs a control command to the device subject to emergency restriction to cancel its operation restriction. The controller 30A then outputs a control command to the water pump 64 and the cooling fan 66 to restart the restriction of their operation.

When the process of step S120 is completed, the controller 30A returns to step S106.

As described above, in this example, the control device 30 controls the cooling system equipment, specifically, the water pump, when the total required current of all the electrical loads to which the low-voltage power supply 44 supplies power is relatively large. 64 and cooling fan 66.

Thereby, the control device 30 can suppress the influence on the operation of the actuator of the excavator 200 and the influence on the operator of the cabin 10 in a situation where the total required current value exceeds the maximum output current of the low voltage power supply 44. can.

<Second example of control processing related to low voltage power supply system>
FIG. 6 is a flowchart schematically showing a second example of control processing regarding the low voltage power supply system of the control device 30 (controller 30A).

As shown in FIG. 6, steps S202 and S204 are the same as steps S102 and S104 in FIG. 5, so the explanation will be omitted.

Step S206 is the same as the process of step S106 in FIG. If the determination condition is met, the controller 30A proceeds to step S208; if the determination condition is not met, the controller 30A proceeds to step S210.

Step S208 is the same as the process of step S108 in FIG. 5, so a description thereof will be omitted.

On the other hand, in step S210, the controller 30A determines whether the temperature of at least one of all the electric drive system devices to be cooled by the cooling circuit 60 exceeds a threshold value TDth12 (<TDth11). If the temperature of at least one of all the electric drive system devices to be cooled in the cooling circuit 60 exceeds the threshold TDth12, the controller 30A proceeds to step S212, and if the temperature does not exceed the threshold TDth12, returns to step S206. .

In step S212, the controller 30A notifies the operator, through the output device 50, of advance notice regarding the operational restriction of the electrical load (equipment subject to emergency restriction). The advance notice regarding the operational restriction of electric loads is a notification informing that there is a possibility that operational restriction will be performed on the electric load that may affect the operator among all the electric loads to which the low-voltage power supply 44 supplies power. . Thereby, the control device 30 can prompt the operator to be aware of the operational restrictions of the equipment subject to emergency restriction, and can also prompt the operator to stop unnecessary electrical loads used in the cabin 10.

Furthermore, in step S212, the controller 30A may issue a notification urging the operator to take a break instead of providing advance notification regarding the restriction of the operation of the electric load. Thereby, the controller 30A can stop the work of the shovel 200 as the operator takes a break, and reduce the total required current value of the electrical loads to which the low-voltage power supply 44 supplies power.

When the process of step S212 is completed, the controller 30A proceeds to step S214.

Steps S214 to S224 are the same as steps S110 to S120 in FIG. 5, so their explanation will be omitted.

In this way, in this example, the control device 30 provides an emergency warning to the operator when the operation of the cooling system equipment is restricted and the temperature of the electric drive system equipment is relatively high. Provides advance notice of operational restrictions on restricted devices and notifications to urge you to take a break.

Thereby, the control device 30 can prompt the operator to suppress the use of the electrical load to which the low-voltage power supply 44 supplies power.

<Third example of control processing related to low voltage power supply system>
7 and 8 are flowcharts schematically showing a third example of control processing regarding the low voltage power supply system of the control device 30 (controller 30A).

As shown in FIG. 7, in step S302, the controller 30A determines whether the total required current of all the electrical loads to which the low-voltage power supply 44 supplies power exceeds a threshold value Ith11. The threshold value Ith11 is an adaptive value that is set smaller than the maximum output current of the low voltage power supply 44. If the total requested current value exceeds the threshold value Ith11, the controller 30A proceeds to step S304, and if it does not exceed the threshold value Ith11, the controller 30A ends the process of the current flowchart.

In step S304, the controller 30A outputs a control command to the cooling fan 66 to limit its operation. Thereby, the control device 30 can continue the circulation of the refrigerant in the cooling circuit 60 by the water pump 64 while reducing the total required current value of all the electrical loads to which the low-voltage power supply 44 supplies power.

When the process of step S304 is completed, the controller 30A proceeds to step S306.

In step S306, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, exceeds the threshold value Ith12. The threshold value Ith12 is an adaptive value set to be larger than the threshold value Ith11 and less than or equal to the maximum output current of the low voltage power supply 44. The controller 30A proceeds to step S308 if the total required current value, assuming that there is no operation restriction, exceeds the threshold value Ith12, and proceeds to step S316 if it does not exceed the threshold value Ith12.

In step S308, the controller 30A outputs a control command to the water pump 64 to limit its operation. Thereby, the control device 30 can further reduce the total required current value of all the electrical loads to which the low-voltage power supply 44 supplies power.

When the process of step S308 is completed, the controller 30A proceeds to step S310.

As shown in FIG. 8, in step S310, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is equal to or less than a threshold value Ith22. Threshold value Ith22 is an adaptive value set to be equal to or less than threshold value Ith12. The controller 30A proceeds to step S312 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith22, and proceeds to step S334 when it is not equal to or less than the threshold value Ith22.

In step S312, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is less than or equal to the threshold value Ith21. The threshold value Ith21 is an adaptive value that is smaller than the threshold value Ith22 and is set to be equal to or less than the threshold value Ith11. The controller 30A proceeds to step S314 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith21, and proceeds to step S332 when it is not equal to or less than the threshold value Ith21.

In step S314, the controller 30A outputs a control command to the water pump 64 and the cooling fan 66 to release their operational restrictions.

When the process of step S314 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, as shown in FIG. 7, in step S316, the controller 30A determines whether the total required current value, assuming that there is no operation restriction, is equal to or less than the threshold value Ith21. The controller 30A proceeds to step S318 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith21, and proceeds to step S320 when it is not equal to or less than the threshold value Ith21.

In step S318, the controller 30A outputs a control command to the cooling fan 66 to cancel its operation restriction.

When the process of step S318 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, in step S320, the controller 30A determines whether the temperature of at least one of all the electric drive system devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth11. If the temperature of at least one of all the electric drive system devices to be cooled in the cooling circuit 60 exceeds the threshold value TDth11, the controller 30A proceeds to step S322, and if the temperature does not exceed the threshold value TDth11, returns to step S306.

In step S322, the controller 30A outputs a control command to the emergency restriction target device to restrict its operation. Then, the controller 30A outputs a control command to the cooling fan 66 to release the restriction on its operation. Thereby, the control device 30 can suppress the temperature rise of the electric drive system equipment while continuing to suppress the total required current value of the electric loads to which the low-voltage power supply 44 supplies power.

Note that, as in the case of the second example (FIG. 6) described above, the operator may be notified in advance of the restriction of the operation of the device subject to emergency restriction, or may be notified to urge him to take a break. In this case, processing similar to steps S210 and S212 in FIG. 6 may be added between step S316 and step S320.

When the process of step S322 is completed, the controller 30A proceeds to step S324.

In step S324, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is less than or equal to the threshold value Ith21. The controller 30A proceeds to step S326 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith21, and proceeds to step S328 when it is not equal to or less than the threshold value Ith21.

In step S326, the controller 30A outputs a control command to the emergency restriction target device and cancels the operation restriction. As a result, all operational restrictions in all electrical loads to which the low-voltage power supply 44 supplies power are released.

When the process of step S326 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, in step S328, the controller 30A determines whether the temperatures of all the electric drive system devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth21. The controller 30A proceeds to step S330 when the temperature of all electric drive system devices to be cooled in the cooling circuit 60 is below the threshold value TDth21, and returns to step S324 when the temperature is not below the threshold value TDth21.

In step S330, the controller 30A outputs a control command to the emergency restriction target device to cancel its operation restriction. Then, the controller 30A outputs a control command to the cooling fan 66 and resumes limiting its operation.

When the process of step S330 is completed, the controller 30A returns to step S306.

On the other hand, as shown in FIG. 8, in step S332, the controller 30A outputs a control command to the water pump 64 to cancel its operation restriction. As a result, in response to a certain decrease in the total required current value, a state is entered in which only the cooling fan 66 of the cooling system equipment is restricted in operation.

When the process of step S332 is completed, the controller 30A returns to step S306.

On the other hand, in step S334, the controller 30A determines whether the temperature of at least one of all the electric drive system devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth11. If the temperature of at least one of all the electric drive system devices to be cooled in the cooling circuit 60 exceeds the threshold value TDth11, the controller 30A proceeds to step S336, and if the temperature does not exceed the threshold value TDth11, returns to step S310.

In step S336, the controller 30A outputs a control command to the emergency restriction target device to restrict its operation. Then, the controller 30A outputs a control command to the water pump 64 and the cooling fan 66, and releases the operational restrictions. Thereby, the control device 30 can suppress the temperature rise of the electric drive system equipment while continuing to suppress the total required current value of the electric loads to which the low-voltage power supply 44 supplies power.

Note that, as in the case of the second example (FIG. 6) described above, the operator may be notified in advance of the operational restriction of the device subject to emergency restriction, or may be notified to urge him to take a break. In this case, processing similar to steps S210 and S212 in FIG. 6 may be added between step S310 and step S334.

When the process of step S336 is completed, the controller 30A proceeds to step S338.

In step S338, the controller 30A determines whether the total required current value, assuming that there are no operational restrictions, is less than or equal to the threshold value Ith21. The controller 30A proceeds to step S340 when the total required current value assuming no operation restriction is equal to or less than the threshold value Ith21, and proceeds to step S342 when it is not equal to or less than the threshold value Ith21.

In step S340, the controller 30A outputs a control command to the emergency restriction target device and cancels the operation restriction. As a result, all operational restrictions in all electrical loads to which the low-voltage power supply 44 supplies power are released.

When the process of step S340 is completed, the controller 30A ends the process of the current flowchart.

On the other hand, in step S342, the controller 30A determines whether the temperatures of all the electric drive system devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth21. The controller 30A proceeds to step S344 when the temperature of all electric drive system devices to be cooled in the cooling circuit 60 is below the threshold value TDth21, and returns to step S338 when it is not below the threshold value TDth21.

In step S344, the controller 30A outputs a control command to the emergency restriction target device and cancels the operation restriction. Then, the controller 30A outputs a control command to the water pump 64 and the cooling fan 66, and resumes restricting their operation.

When the process of step S344 is completed, the controller 30A returns to step S310.

In this way, in this example, when the total required current value of all the electrical loads to which low-voltage power supply 44 supplies power is relatively large, the control device 30 limits the operation as the total required current value increases. The number of cooling system equipment will be gradually increased.

As a result, the control device 30 reduces the total required current of all the electrical loads to which the low-voltage power supply 44 supplies power, limits the range of operational restrictions of the cooling system equipment, and limits the range of operation restrictions of the cooling system equipment. The influence on the temperature of electric drive system equipment can be suppressed.

Note that when a plurality of cooling fans 66 are provided, the control device 30 may gradually increase the number of cooling fans whose operations are restricted among the plurality of cooling fans 66 using a method similar to this example. In addition, when an oil cooler fan is provided in addition to the cooling fan 66, the control device 30 gradually controls the number of cooling system devices whose operation is restricted, including the oil cooler fan, in the same manner as in this example. It may be increased to In addition, the controller 30A controls the operation of two or more of all the electrical loads to which the low-voltage power supply 44 supplies power, including electrical loads other than cooling system equipment, in the same manner as in this example. The number of electrical loads to be restricted may be increased in stages.

Furthermore, in this example, when the total required current of all the electrical loads to which the low-voltage power supply 44 supplies power is relatively large, the control device 30 gives priority to the cooling fan 66 of the cooling system equipment. suppress.

Thereby, when restricting cooling system equipment, the control device 30 can continue the operation of the water pump 64 depending on the magnitude of the total required current value. Therefore, the control device 30 can suppress a decrease in the degree of cooling (cooling efficiency) of the electric drive system equipment even in a situation where it is necessary to restrict the operation of the cooling system equipment.

Note that if an oil cooler fan is provided in addition to the cooling fan 66, the control device 30 may restrict the operation of the oil cooler fan with priority over the water pump 64 in the same manner as in this example. . This is because the hydraulic oil in the hydraulic drive system is circulated by the main pump 14, and even if the operation of the oil cooler fan is restricted, cooling of the hydraulic oil through heat exchange in the oil cooler 70 can be promoted to some extent. .

[Effect]
Next, with reference to FIG. 9, the operation of the shovel 200 according to this embodiment will be described.

In this embodiment, the excavator 200 includes a low-voltage power source 44 and a plurality of electrical loads that operate with power supplied from the low-voltage power source 44. The maximum value of the current that the low voltage power supply 44 can output (maximum output current) is smaller than the maximum value of the current (total of required currents) required to operate the plurality of electrical loads. Specifically, the maximum output current of the low voltage power supply 44 is set to be smaller than the total value of the rated currents of the plurality of electrical loads.

For example, FIG. 9 is a diagram showing a specific example of the relationship between the total required current (required current total value) of a plurality of electrical loads to which the low-voltage power supply 44 supplies power and the frequency of occurrence.

As shown in FIG. 9, in the excavator 200, the frequency of occurrence of a state in which the total required current value is extremely large (a state in the "operation restriction range" in the figure) is often very low. Therefore, if the maximum output current of the low-voltage power supply 44 is set according to a situation where the occurrence frequency is relatively low, the low-voltage power supply 44 (specifically, DC - The energy efficiency of the DC converter 44A) may be relatively reduced. Therefore, there is a possibility that the energy efficiency of the low-voltage power supply 44 as a whole while the excavator 200 is in operation will be significantly reduced. In particular, since the DC-DC converter 44A uses the power of the power storage device 19 to supply power to a plurality of electrical loads, as the energy efficiency decreases, the amount of stored power in the power storage device 19 decreases more quickly, and the amount of power stored in the power storage device 19 decreases more quickly. Uptime may be significantly reduced. In addition, for example, in the case of an excavator equipped with an engine, the main pump 14 cannot be driven or generated by the power of the engine, so a decrease in the energy efficiency of the low-voltage power supply 44 significantly affects the operating time of the excavator 200. may have an impact.

On the other hand, in this embodiment, the maximum output current of the low voltage power supply 44 can be set to be smaller than the maximum value of the current (total of required currents) necessary for operating a plurality of electrical loads to some extent. Therefore, the excavator 200 can suppress a decrease in the energy efficiency of the low voltage power supply 44 (specifically, the DC-DC converter 44A) in the range of the total required current value that occurs relatively frequently. In particular, in the excavator 200 according to the present embodiment, the power of the power storage device 19 is used to operate the actuator that drives the driven element. The reduction in operating time can be suppressed.

Further, in the present embodiment, the control device 30 limits the operation of some of the electrical loads when the current required for the plurality of electrical loads (total required current value) is relatively large. .

As a result, for example, in a situation where the total required current value is likely to exceed the maximum output current of the low voltage power source 44, the shovel 200 operates so that the total required current value is equal to or less than the maximum output current of the low voltage power source 44. It is possible to limit the operation of certain electrical loads with less impact on Therefore, the excavator 200 can more appropriately adjust the operating status of the plurality of electrical loads that operate with the power from the low-voltage power source 44 while suppressing a decrease in the energy efficiency of the low-voltage power source 44.

Further, in the present embodiment, a priority regarding operation restriction may be predefined for each of the plurality of electrical loads. Then, when the current required by the plurality of electrical loads is relatively large, the control device 30 may limit the operation of some of the electrical loads with relatively high priority.

Thereby, for example, in a situation where the total required current value is likely to exceed the maximum output current of the low-voltage power supply 44, the control device 30 specifically controls the operation of a specific electrical load that has a high priority of predefined operation restrictions. can be restricted.

Furthermore, in this embodiment, some of the electrical loads whose operation is restricted when the current required for the plurality of electrical loads is relatively large include cooling system equipment that cools the electric drive system equipment. good.

Thereby, the control device 30 can limit the operation of cooling system equipment that has little effect on the operation of the excavator 200, for example, in a situation where the total required current value is likely to exceed the maximum output current of the low voltage power supply 44. For example, in the cooling circuit 60, there is a refrigerant with a very large volume, that is, a large heat capacity, and even if the operation of the cooling system equipment is temporarily restricted, the temperature of the electric drive system equipment will suddenly rise. This is because there is no need to put it away.

Further, in the present embodiment, cooling system equipment whose operation is restricted when the current required for a plurality of electrical loads is relatively large may include the cooling fan 66 and the water pump 64. The control device 30 may preferentially limit the operation of the cooling fan 66 of the water pump 64 and the cooling fan 66 when the current required for the plurality of electrical loads is relatively large.

As a result, the excavator 200 can suppress a decrease in the degree of cooling of the electrically driven equipment even in a situation where it is necessary to restrict the operation of the cooling system equipment. Even when the operation of the cooling fan 66 is restricted and the air blowing to the radiator 62 is restricted, if the circulation of the refrigerant continues, the cooling efficiency will decrease, but the heat between the refrigerant in the radiator 62 and the outside air will be reduced. This is because cooling of the electric drive system equipment is promoted to some extent by replacement.

Furthermore, when the temperature of the electric drive system equipment becomes relatively high while the operation of the cooling system equipment is restricted, the control device 30 allows the operator to control at least one of the plurality of electrical loads through the output device 50. Restrictions on some uses may be encouraged.

As a result, the excavator 200 allows the operator to voluntarily limit the use of the electric load in a situation where the temperature of the electric drive system equipment has increased to some extent due to restrictions on the operation of the cooling system equipment. Therefore, for example, in order to suppress the temperature rise of electric drive system equipment, the excavator 200 cancels the operation restrictions of the cooling system equipment, and instead forcibly restricts the operation of the electric load that affects the operator. , it is possible to suppress the occurrence of situations that give discomfort to the operator.

[Transformation/Change]
Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist described in the claims.

For example, in the embodiment described above, a method of setting the maximum output current of the low voltage power supply 44 mounted on the excavator 200 without an engine and a method of controlling the low voltage power supply system have been described. It may also be applied to the low voltage power supply system of excavators.

Furthermore, in the above-described embodiments and examples of modifications/changes, the method of setting the maximum output current of the low-voltage power supply and the control method regarding the low-voltage power supply system have been described, but the same method can be applied to the high-voltage power supply (power storage device 19 and device 100).

In addition, in the above-mentioned embodiment and examples of modifications and changes, the method of setting the maximum output current of the low-voltage power supply installed in the excavator and the control method regarding the low-voltage power supply system were explained, but the same method can be applied to other working machines. It may be applied to low-voltage power supply systems. Other work machines include, for example, industrial vehicles, forklifts, cranes, bulldozers, and the like.

12 Pump electric motor (electric actuator)
14 Main pump 15 Pilot pump 17 Control valve 17A Solenoid actuator 18 Inverter unit 18A Inverter 18B Inverter 19 Power storage device 21 Swivel motor (electric actuator)
26 Operating device (electrical load)
30 Control device 30A to 30C Controller (electrical load)
31 Pressure control valve (electrical load)
44 Low voltage power supply (power supply)
44A DC-DC converter (power conversion device)
44B battery 50 output device (electric load)
52 Input device (electrical load)
60 Cooling circuit 62 Radiator 64 Water pump (electrical load, cooling system equipment)
66 Cooling fan (electrical load, cooling system equipment)
70 Oil cooler 80 Air conditioner (electrical load)

Claims (9)

power supply and
a plurality of electrical loads that operate with power supplied from the power source,
The maximum value of the current that the power supply can output is smaller than the maximum value of the current required to operate the plurality of electrical loads,
If the current required for the plurality of electrical loads is relatively large, restricting the operation of some of the electrical loads,
The some electrical loads include cooling system equipment that cools predetermined heat source equipment,
prompting an operator to restrict the use of at least some of the plurality of electrical loads when the temperature of the heat source equipment becomes relatively high while the operation of the cooling system equipment is restricted;
shovel. power supply and
a plurality of electrical loads that operate with power supplied from the power source,
The maximum value of the current that the power supply can output is smaller than the maximum value of the current required to operate the plurality of electrical loads,
If the current required for the plurality of electrical loads is relatively large, restricting the operation of some of the electrical loads,
The some electrical loads include cooling system equipment that cools predetermined heat source equipment,
The cooling system equipment includes a cooling fan that blows air to a heat exchanger that performs heat exchange between the refrigerant flowing inside and outside air, and a cooling fan that blows air to a heat exchanger that exchanges heat between the refrigerant flowing inside and outside air, and a cooling circuit that supplies the refrigerant with the heat source equipment and the heat exchanger. and a refrigerant pump that circulates the refrigerant.
When the current required for the plurality of electrical loads is relatively large, preferentially limiting the operation of the cooling fan of the cooling fan and the refrigerant pump;
shovel. The maximum value of the current that the power supply can output is smaller than the total rated current of each of the plurality of electrical loads.
The excavator according to claim 1 or 2 . Each of the plurality of electrical loads is predefined with a priority regarding operation restriction,
The some electrical loads are electrical loads having a relatively high priority among the plurality of electrical loads,
An excavator according to any one of claims 1 to 3. The cooling system equipment includes a cooling fan that blows air to a heat exchanger that performs heat exchange between the refrigerant flowing inside and outside air, and a cooling fan that blows air to a heat exchanger that exchanges heat between the refrigerant flowing inside and outside air, and a cooling circuit that supplies the refrigerant with the heat source equipment and the heat exchanger. and a refrigerant pump that circulates the refrigerant.
preferentially limiting the operation of the cooling fan when the current required for the plurality of electrical loads is relatively large;
The excavator according to claim 1 . prompting an operator to restrict the use of at least some of the plurality of electrical loads when the temperature of the heat source equipment becomes relatively high while the operation of the cooling system equipment is restricted;
The excavator according to claim 2 . electric actuator;
a power storage device having a relatively higher voltage than the power source and supplying power to the electric actuator,
The power source includes a power conversion device that steps down the power of the power storage device and outputs the voltage to the plurality of electrical loads.
A shovel according to any one of claims 1 to 6 . The power source outputs a relatively low voltage to the plurality of electrical loads,
The plurality of electrical loads do not include equipment that outputs power for driving driven elements of the excavator.
A shovel according to any one of claims 1 to 7 . a lower running body;
an upper rotating body rotatably mounted on the lower traveling body;
a boom attached to the upper revolving body;
an arm attached to the tip of the boom;
an end attachment attached to the tip of the arm;
an electric actuator that outputs power for driving the lower traveling body, the upper revolving body, the boom, the arm, and the end attachment;
and a power storage device that supplies power to the electric actuator.
A shovel according to any one of claims 1 to 8 .

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