JP2024050678A - Excavator - Google Patents

Abstract

[Problem] To provide a technique for more appropriately adjusting the degree of heat exchange in equipment that exchanges heat with outside air in a shovel. [Solution] A shovel according to an embodiment of the present disclosure includes a plurality of fans 90 (e.g., fans 90G, 90H and fans 90I, 90J) capable of blowing air toward a predetermined equipment that exchanges heat with outside air (e.g., a radiator 62 and an oil cooler 72). The plurality of fans 90 include a first fan (e.g., fan 90H and fan 90J) capable of blowing air only toward the predetermined equipment and other equipment that is different from the predetermined equipment and exchanges heat with outside air (e.g., a condenser 82B), and a second fan (e.g., fan 90G and fan 90I) capable of blowing air toward the predetermined equipment to which the first fan can blow air and the other equipment. [Selected Figure] FIG.

Description

This disclosure relates to a shovel.

Conventionally, there is known a technique for changing the rotation speed of a fan that blows air toward a device (e.g., an oil cooler) that exchanges heat with the outside air in response to changes in the temperature of a fluid (e.g., hydraulic oil) flowing through the device (see Patent Document 1).

JP 2019-208568 A

However, the above technology only changes the rotation speed of one fan. Therefore, it would be desirable to be able to adjust the degree of heat exchange (degree of cooling or heating) in the target device more precisely.

In view of the above problems, the objective is to provide a technology that can more appropriately adjust the degree of heat exchange in equipment that exchanges heat with the outside air in an excavator.

In order to achieve the above object, in one embodiment of the present disclosure,
A plurality of fans are provided to blow air toward a predetermined device that exchanges heat with the outside air,
The plurality of fans include a first fan capable of blowing air only to the predetermined device among the other devices that are different from the predetermined device and exchange heat with outside air, and a second fan capable of blowing air to the predetermined device to which the first fan can blow air and the other devices,
Shovel provided.

According to the above-described embodiment, it is possible to provide a technology that can more appropriately adjust the degree of heat exchange in equipment that exchanges heat with the outside air in a shovel.

FIG. FIG. 2 is a block diagram illustrating an example of a configuration of a shovel. FIG. 2 is a diagram showing an example of a cooling circuit for an electric drive system. FIG. 1 is a diagram illustrating an example of a heat pump cycle of an air conditioner. FIG. 2 is a diagram illustrating a first example of an arrangement of a radiator, an oil cooler, a condenser, and a fan. FIG. 2 is a diagram illustrating a first example of an arrangement of a radiator, an oil cooler, a condenser, and a fan. 5 is a flowchart illustrating a first example of a control process for a radiator fan by a controller. 5 is a flowchart illustrating a first example of a control process for a radiator fan by a controller. 5 is a flowchart illustrating a first example of a control process for an oil cooler fan by a controller. 5 is a flowchart illustrating a first example of a control process for an oil cooler fan by a controller. 5 is a flowchart illustrating a first example of a control process for a condenser fan by a controller. FIG. 13 is a diagram illustrating a second example of an arrangement of a radiator, an oil cooler, a condenser, and a fan. FIG. 13 is a diagram illustrating a second example of an arrangement of a radiator, an oil cooler, a condenser, and a fan. 10 is a flowchart illustrating a second example of a control process for a radiator fan by the controller. 10 is a flowchart illustrating a second example of a control process for a radiator fan by the controller. 10 is a flowchart illustrating a second example of a control process for the oil cooler fan by the controller. 10 is a flowchart illustrating a second example of a control process for the oil cooler fan by the controller. 10 is a flowchart illustrating a second example of a control process for the condenser fan by the controller.

Below, we will explain the form for implementing the invention with reference to the drawings.

[Outline of the excavator]
First, with reference to FIG. 1, an overview of a shovel as an example of a work machine will be described.

Figure 1 is a side view showing an example of a shovel according to this embodiment.

The excavator according to this embodiment includes a lower carrier 1, an upper rotating body 3 mounted on the lower carrier 1 so as to be rotatable via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments, and a cabin 10 in which the operator sits.

The lower traveling body 1 includes, for example, a pair of left and right crawlers, each of which is hydraulically driven by traveling hydraulic motors 1A, 1B (see Figure 2) to enable self-propulsion.

The upper rotating body 3 rotates relative to the lower traveling body 1 by being electrically driven by a rotating electric motor 21 (see FIG. 2) described later through the rotating mechanism 2. The upper rotating body 3 may also be hydraulically driven by a rotating hydraulic motor instead of the rotating electric motor 21 through the rotating mechanism 2. In this case, the excavator of this embodiment corresponds to a configuration in which all driven elements are hydraulically driven by hydraulic oil supplied from a main pump 14 (see FIG. 2) powered by an engine, so-called a hydraulic excavator with the power source (engine) replaced by a pump electric motor 12.

The boom 4 is attached to the center of the front of the upper rotating body 3 so that it can be raised and lowered, an arm 5 is attached to the tip of the boom 4 so that it can rotate up and down, and a bucket 6 is attached to the tip of the arm 5 so that it can rotate up and down. The boom 4, arm 5, and bucket 6 are hydraulically driven by a boom cylinder 7, arm cylinder 8, and bucket cylinder 9, which serve 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 work content, etc. The other end attachments may be buckets of a different type from the bucket 6, such as a slope bucket or a dredging bucket. The other end attachments may also be end attachments of a different type from the bucket, such as a breaker, mixer, grappler, etc.

The cabin 10 is mounted on the front left side of the upper rotating body 3, and inside it are a cockpit where the operator sits, an operating device 26 (described later), and other equipment.

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

In addition to or instead of being configured to be operable by an operator inside the cabin 10, the shovel may be configured to be remotely operated from outside the shovel. When the shovel is remotely operated, the inside of the cabin 10 may be unmanned. In the following description, it is assumed that the operation of the operator includes at least one of the operation of the operating device 26 by the operator inside the cabin 10 and the remote operation by an external operator.

Remote operation includes, for example, a mode in which the shovel is operated by an operation input related to the actuator of the shovel performed by a specified external device. In this case, the shovel is equipped with a communication device capable of communicating with a specified external device, and may transmit image information (captured image) output by an imaging device included in the surrounding information acquisition device 40 described later to the external device. The external device may then display the received image information (captured image) on a display device (hereinafter, "display device for remote operation") provided in the external device. In addition, various information images (information screens) displayed on the output device 50 (display device) inside the cabin 10 of the shovel may also be displayed on the display device for remote operation of the external device. This allows the operator of the external device to remotely operate the shovel while checking the display contents of the captured image and information screen showing the state of the surroundings of the shovel displayed on the display device for remote operation, for example. The excavator may then operate the hydraulic actuators in response to a remote control signal indicating the content of the remote control, which is received from an external device by the communication device, to drive the driven elements, such as the lower traveling body 1 (left and right crawlers), upper rotating body 3, boom 4, arm 5, and bucket 6.

Remote operation may also include a mode in which the shovel is operated by, for example, external voice input or gesture input to the shovel by people (e.g., workers) around the shovel. Specifically, the shovel recognizes voices uttered by surrounding workers and gestures made by workers through a voice input device (e.g., a microphone) or a gesture input device (e.g., an imaging device) mounted on the shovel (own machine). The shovel may then operate actuators according to the content of the recognized voices and gestures to drive driven elements such as the lower traveling body 1 (left and right crawlers), upper rotating body 3, boom 4, arm 5, and bucket 6.

The excavator may also automatically operate the actuators regardless of the content of the operator's operation. This allows the excavator to realize a function (so-called "automatic driving function" or "machine control function") that automatically operates at least some of the driven elements such as the lower traveling body 1 (crawlers 1CL, 1CR), upper rotating body 3, boom 4, arm 5, and bucket 6.

The automatic driving function may include a function (so-called "semi-automatic driving function") that automatically operates a driven element (hydraulic actuator) other than the driven element (hydraulic actuator) that is the object of operation, in response to the operator's operation of the operating device 26 or remote operation. The automatic driving function may also include a function (so-called "fully automatic driving function") that automatically operates at least a part of the multiple driven elements (hydraulic actuators) on the premise that the operator does not operate the operating device 26 or remote operation. When the fully automatic driving function is enabled in the excavator, the inside of the cabin 10 may be unmanned. The semi-automatic driving function, the fully automatic driving function, etc. may also include a mode in which the operation content of the driven element (hydraulic actuator) that is the object of automatic driving is automatically determined according to a rule that is specified in advance. The semi-automatic driving function, the fully automatic driving function, etc. may also include a mode in which the excavator autonomously makes various judgments and autonomously determines the operation content of the driven element (hydraulic actuator) that is the object of automatic driving in accordance with the judgment results (so-called "autonomous driving function").

[Excavator configuration]
Next, the configuration of the shovel according to this embodiment will be described with reference to FIGS. 2 to 4 in addition to FIG.

Figure 2 is a block diagram showing an example of the configuration of a shovel according to this embodiment. Figure 3 is a diagram showing an example of a cooling circuit 60 of an electric drive system mounted on a shovel according to this embodiment. Figure 4 is a diagram showing an example of a heat pump cycle 82 of an air conditioning device 80 mounted on a shovel according to this embodiment.

In the diagram, mechanical power lines are indicated by double lines, high-pressure hydraulic lines are indicated by thick solid lines, pilot lines are indicated by dashed lines, and electrical drive and control lines are indicated by thin solid lines.

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

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

The main pump 14 draws hydraulic oil from a hydraulic oil tank T and discharges it into a high-pressure hydraulic line 16, thereby supplying hydraulic oil to a control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by a pump motor 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and a regulator (not shown) controls the angle (tilt angle) of the swash plate under the control of a controller 30A described below. This allows the main pump 14 to adjust the stroke length of the piston and control the discharge flow rate (discharge pressure).

The control valve 17 is a hydraulic control device that controls the hydraulic drive system in response to an operation command corresponding to an operator's operation or 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 is configured to selectively supply 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 including a plurality of control valves (directional control valves) that control the flow rate and flow direction of the hydraulic oil supplied from the main pump 14 to each of the hydraulic actuators. The hydraulic oil supplied from the main pump 14 and flowing through the control valve 17 and the hydraulic actuators is discharged from the control valve 17 to the hydraulic oil tank T.

<Electric drive system>
The electric drive system of the shovel according to this embodiment includes the pump motor 12, the sensor 12s, and the inverter 18A. The electric drive system of the shovel according to this embodiment also includes a swing drive device 20, a sensor 21s, and the inverter 18B. The electric drive system of the shovel according to this embodiment includes a high-voltage power supply constituted by a power storage device 19 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 the power path between the pump motor 12 and the inverter 18A. The detection signals corresponding to the current of each of the three phases of the pump motor 12 detected by the current sensor 12s1 are directly input to the inverter 18A via a communication line. The detection signals may also be input to the controller 30B via the communication line and input to the inverter 18A via the controller 30B.

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

The rotation state sensor 12s3 detects the rotation state (e.g., rotation position (rotation angle), rotation speed, etc.) of the pump 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 includes, for example, a conversion circuit that converts DC power to three-phase AC power and converts three-phase AC power to DC power, a drive circuit that switches and drives the conversion circuit, and a control circuit that outputs a control signal (for example, a PWM (Pulse Width Modulation) signal) that specifies the operation of the drive circuit.

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. The control circuit of the inverter 18A may also grasp the operating state of the pump motor 12 by successively estimating the rotation angle of the rotating shaft of the pump motor 12 based on the detection signal of the current sensor 12s1 and the detection signal of the voltage sensor 12s2 (or a voltage command value generated during the control process).

The slewing drive device 20 includes a slewing motor 21, a resolver 22, a mechanical brake 23, and a slewing reducer 24. The slewing motor 21 performs a powering operation to drive the upper slewing body 3 to rotate, and a regenerative operation to generate regenerative power and brake the upper slewing body 3 to rotate, under the control of the controller 30B and the inverter 18B. The slewing motor 21 is connected to a high-voltage power source (i.e., the storage device 19) via the inverter 18B, and is driven by three-phase AC power supplied from the storage device 19 via the inverter 18B. The slewing motor 21 also supplies regenerative power to the storage device 19 and the pump motor 12 via the inverter 18B. This allows the regenerative power to be used to charge the storage device 19 and drive the pump motor 12. The switching control between power running and regenerative operation of the turning 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 turning reduction gear 24 are connected to the rotating shaft 21A of the turning motor 21.

The resolver 22 detects the rotation state (e.g., rotation position (rotation angle) and rotation speed, etc.) of the turning motor 21. A detection signal corresponding to the rotation angle, etc. detected by the resolver 22 may be directly input to the inverter 18B via a communication line. The detection signal may also be input to the controller 30B via a 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 rotation motor 21 under the control of the controller 30B. This allows the mechanical brake 23 to brake the rotation of the upper rotating body 3 or to maintain the upper rotating body 3 in a stopped state.

The slewing reduction gear 24 is connected to the rotating shaft 21A of the slewing motor 21, and reduces the output (torque) of the slewing motor 21 at a predetermined reduction ratio, thereby increasing the torque and driving the upper slewing body 3 to rotate. That is, during power running, the slewing motor 21 drives the upper slewing body 3 to rotate via the slewing reduction gear 24. The slewing reduction gear 24 also increases the inertial rotational force of the upper slewing body 3 and transmits it to the slewing motor 21 to generate regenerative power. That is, during regenerative operation, the slewing motor 21 generates regenerative power using the inertial rotational force of the upper slewing body 3 transmitted via the slewing reduction gear 24, and brakes the upper slewing body 3 to rotate.

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 motor 21. The current sensor 21s1 is provided, for example, in the power path between the turning motor 21 and the inverter 18B. The detection signal corresponding to the current of each of the three phases of the turning motor 21 detected by the current sensor 21s1 may be directly input to the inverter 18B via a communication line. The detection signal may also be input to the controller 30B via the communication line and input to the inverter 18B via the controller 30B.

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

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

For example, the control circuit of the inverter 18B performs speed feedback control and torque feedback control for the turning 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 a single housing and together form inverter unit 18.

In addition, at least one of the drive circuit and control circuit of inverter 18B may be provided outside inverter 18B.

The power storage device 19 is charged (stores electricity) by being connected to an external commercial power source via a specified cable, and supplies the charged (stored) electricity to the pump motor 12 and the turning motor 21 via a DC (Direct Current) bus 110. The power storage device 19 also stores the generated electricity (regenerated electricity) of the turning motor 21. The power storage device 19 is, for example, a lithium-ion battery, and has a relatively high output voltage (for example, several hundred volts).

A power conversion device may be provided between the storage device 19 and the DC bus 110 to boost the output voltage of the storage device 19 and apply it to the pump motor 12 and the turning motor 21. In this case, the power conversion device boosts the power of the storage device 19, or reduces the power of the pump motor 12 and the turning motor 21 via the inverters 18A and 18B to store the power in the storage device 19. The power conversion device may switch between a boost operation and a step-down operation so that the voltage value of the DC (Direct Current) bus 110 falls within a certain range depending on the operating state of the pump motor 12 and the turning motor 21. The switching control between the boost operation and the step-down operation of the power conversion device may be executed by the controller 30B, for example, based on the voltage detection value of the DC bus 110, the voltage detection value of the storage device 19, and the current detection value of the storage device 19.

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

The pilot pump 15 supplies pilot pressure to various hydraulic devices (e.g., pressure control valve 31) mounted on the excavator via the pilot line 25. As a result, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the operation content (e.g., the 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 operation content of the operator on the operating device 26. In addition, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the remote operation content specified by the remote operation signal under the control of the controller 30A. The pilot pump 15 is, for example, a fixed displacement hydraulic pump, and is driven by the pump motor 12 as described above.

The operating device 26 is provided within reach of the operator in the cockpit of the cabin 10, and is used by the operator to operate each driven element (i.e., the left and right crawlers of the lower traveling body 1, the upper rotating body 3, the boom 4, the arm 5, and the bucket 6, etc.). In other words, the operating device 26 is used by the operator to operate the hydraulic actuators (e.g., the traveling hydraulic motors 1A and 1B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9, etc.) and the electric actuators (the swing electric motor 21, etc.) that drive each driven element. The operating device 26 is, for example, electric, and outputs an electric signal (hereinafter, "operation signal") according to the operation content by the operator. The operation signal output from the operating device 26 is taken into the controller 30A. As a result, the control device 30 including the controller 30A can control the pressure control valve 31 and the inverter 18B, and control the operation of the driven elements (actuators) of the excavator according to the operation content of the operator and the operation command corresponding to the automatic driving function.

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

When the control valve 17 is configured as an electromagnetic pilot type hydraulic control valve (directional control valve), the operation signal of the electric operating device 26 may be input directly to the control valve 17, and each hydraulic control valve may perform an operation according to the operation of the operating device 26. The operating device 26 may also be of a hydraulic pilot type that outputs a pilot pressure according to the operation. In this case, the pilot pressure according to the operation is supplied to the control valve 17.

Under the control of the controller 30A, the pressure control valve 31 outputs a predetermined pilot pressure using hydraulic oil supplied from the pilot pump 15 through the pilot line 25. The secondary pilot line 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 the excavator according to this embodiment includes a control device 30, an ambient information acquisition device 40, an output device 50, an input device 52, a temperature sensor 54, and an oil temperature sensor 56.

The control device 30 includes controllers 30A to 30C.

The functions of controllers 30A to 30C may be realized by any hardware or any combination of hardware and software. For example, controllers 30A to 30C may each be configured around a computer including a processor such as a CPU (Central Processing Unit), a memory device (main storage device) such as a RAM (Random Access Memory), a non-volatile auxiliary storage device such as a ROM (Read Only Memory), and an interface device with the outside.

Controller 30A works in conjunction with various controllers constituting control device 30, including controllers 30B and 30C, to control the drive of the shovel.

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 corresponding to the operation of the operating device 26. In this way, the controller 30A can realize the operation of the driven element (hydraulic actuator) of the excavator corresponding to the operation of the electric operating device 26.

In addition, when the shovel is remotely operated, the controller 30A may, for example, perform control related to the remote operation. 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 corresponding to the content of the remote operation. In this way, the controller 30A can realize the operation of the shovel (driven element) corresponding to the content of the remote operation.

The controller 30A may also perform control related to, for example, the automatic driving function. Specifically, the controller 30A may output a control command to the pressure control valve 31, and cause the pressure control valve 31 to apply a pilot pressure corresponding to an operation command corresponding to the automatic driving function to the control valve 17. This allows the controller 30A to realize the operation of the driven element (hydraulic actuator) of the excavator corresponding to the automatic driving function.

In addition, controller 30A may comprehensively control the operation of the entire shovel (various devices mounted on the shovel) based on bidirectional communication with various controllers such as controllers 30B and 30C.

The controller 30A may also control, for example, a function for automatically stopping the main pump 14 (hereinafter, the "pump stop function").

Specifically, the controller 30A may automatically stop the main pump 14 when the operator continues not to operate the shovel (operate the operating device 26 or remotely operate the shovel) while the shovel is in operation (driving). This allows the controller 30A to stop the operation of the main pump 14, that is, the pump motor 12, which is not necessary when the shovel is not being operated. This makes it possible to suppress the power of the power storage device 19 consumed by the pump motor 12. Furthermore, the controller 30A may stop the main pump 14 when a predetermined input indicating an intention to stop the main pump 14 is received through the input device 52 while the shovel is in operation (driving). This allows the controller 30A to stop the main pump 14 (pump motor 12) reflecting the operator's intention. Therefore, for example, in a situation where the operating noise of the main pump 14 (pump motor 12) during operation is causing problems in communicating with surrounding workers, the operator can temporarily reduce the operating noise and communicate with surrounding workers by making a specific input through the input device 52.

For example, the control device 30 (controllers 30A and 30B) starts the main pump 14, i.e., the pump motor 12, when the shovel is started (for example, when the key switch is turned on), regardless of whether the operating device 26 is operated or not. As a result, the control device 30 can start the pump motor 12 once when the shovel is started, and transition the pump motor 12 to a controllable state. In addition, the control device 30 can start the pump motor 12 once when the shovel is started, and perform a diagnostic process for the presence or absence of an abnormality in the pump motor 12, etc. For example, the controller 30B diagnoses the presence or absence of an abnormality by passing electricity through the inverter 18A to the pump motor 12. If an abnormality is detected, the controller 30B may notify the operator that an abnormality is detected in the pump motor 12 through the output device 50 or the like. On the other hand, if there is no abnormality in the pump motor 12 and the operation of the operating device 26 is not started thereafter, the controller 30B may stop the pump motor 12 by the pump stop function. Then, the controller 30A may automatically start the pump motor 12 when the operator starts operating the pump, and thereafter, each time a continuous non-operating state is detected, the controller 30A may automatically stop the pump motor 12, and may repeat the process of automatically starting the pump motor 12 when the operator starts operating the pump.

The controller 30A may also control, for example, the operation and stopping of the fan 90. Details will be described later (see Figures 5 to 18).

The controller 30B controls the drive of the electric drive system based on various information input from the controller 30A (e.g., control commands including the operation signal of the operating device 26, etc.).

The controller 30B may, for example, drive the inverter 18B based on the operation of the operating device 26, and control the switching of the operating state (powered operation and regenerative operation) of the turning motor 21. Also, for example, when the shovel is remotely operated, the controller 30B may drive the inverter 18B based on the remote operation, and control the switching of the operating state (powered operation and regenerative operation) of the turning motor 21. Also, for example, when the automatic operation function of the shovel is enabled, the controller 30B may drive the inverter 18B based on an operation command corresponding to the automatic operation function, and control the switching of the operating state (powered operation and regenerative operation) of the turning motor 21.

When the above-mentioned power conversion device is provided between the storage device 19 and the DC bus 110, the controller 30B may, for example, drive the power conversion device based on the operation state of the operation device 26, and control the step-up and step-down operation of the power conversion device, in other words, the switching between the discharged state and the charged state of the storage device 19. When the shovel is remotely operated, for example, the controller 30B may drive the power conversion device based on the content of the remote operation, and control the switching between the discharged state and the charged state of the storage device 19. When the automatic operation function of the shovel is enabled, for example, the controller 30B may drive the power conversion device based on an operation command corresponding to the automatic operation function, and control the switching between the discharged state and the charged state of the storage device 19.

In addition, the controller 30B may control the stopping and starting of the pump motor 12, for example, in response to a control command from the controller 30A regarding the pump stop function.

The controller 30C controls the excavator's peripheral monitoring function.

The controller 30C detects specific objects and their positions around the shovel (hereinafter, "monitoring targets") based on, for example, information about the three-dimensional spatial situation around the shovel (for example, detection information about objects around the shovel and their positions) acquired from the surrounding information acquisition device 40.

In addition, for example, if the controller 30C detects a monitored object in an area relatively close to the shovel, it may output an alarm through an output device 50 (e.g., a display device, a sound output device, etc.) inside the cabin 10.

The functions of controllers 30B and 30C may be integrated into controller 30A. In other words, the various functions realized by control device 30 may be realized by one controller, or may be distributed and realized by two or more controllers that are appropriately set.

The surrounding information acquisition device 40 outputs information about the situation in the three-dimensional space around the shovel. 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, etc. 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 (e.g., 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 is, for example, installed in a location that is easily visible to the operator in the cabin 10, 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. The output device 50 also includes, for example, a sound output device that outputs information to the operator in an auditory manner. The sound output device is, for example, a buzzer or a speaker.

The input device 52 is provided in the cabin 10 and accepts various inputs from the operator. The input device 52 may include, for example, an operation input device that accepts operation input from the operator. The operation input device includes, for example, a button, a toggle, a lever, a touch panel, a touch pad, etc. The input device 52 may also include, for example, a voice input device that accepts voice input from the 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 in the cabin 10. The gesture input device includes, for example, an indoor camera that can capture images of the operator's gestures in the cabin 10. A signal corresponding to the input from the operator accepted by the input device 52 is taken into the control device 30 (for example, controller 30A).

The temperature sensor 54 detects the temperature of the electric drive system equipment to be cooled by the cooling circuit 60 described below. The temperature sensor 54 includes, for example, a temperature sensor that detects the temperature of the pump motor 12. The temperature sensor 54 also includes a temperature sensor that detects the temperature of the inverter 18A. The temperature sensor 54 also includes a temperature sensor that detects the temperature of the inverter 18B. The temperature sensor 54 also includes, for example, a temperature sensor that detects the temperature of the storage device 19. The temperature sensor 54 also includes, for example, a temperature sensor that detects the temperature of the turning motor 21. The temperature sensor 54 also includes, for example, a temperature sensor that detects the temperature of the DC-DC converter 44 described below. The detection signal of the temperature sensor 54 is taken in, for example, by the controller 30A. This allows the controller 30A to grasp the temperature state of the electric drive system equipment.

In addition, if a power conversion device is provided between the storage device 19 and the DC bus 110, the temperature sensor may include a temperature sensor that grasps the temperature state of the power conversion device.

The oil temperature sensor 56 detects the temperature of the hydraulic oil that drives the hydraulic actuator (hereinafter, "hydraulic oil temperature"). The oil temperature sensor 56 may detect, for example, the temperature of the hydraulic oil inside the hydraulic oil tank T. The detection signal of the oil temperature sensor 56 is input, for example, to the controller 30A. This allows the controller 30A to grasp the temperature state of the hydraulic oil.

<Other components>
The shovel according to this embodiment includes a DC-DC converter 44 , a battery 46 , a cooling circuit 60 , an oil cooler 70 , an air conditioner 80 , and a fan 90 .

The DC-DC converter 44 is provided, for example, on the upper rotating body 3, and reduces the extremely high voltage DC power output from the power storage device 19 to a predetermined voltage (for example, about 24 volts) and outputs it. The output power of the DC-DC converter 44A is supplied to the battery 46 and charged (stored) or supplied to electrical devices that are driven by the power of the battery 46, such as the controllers 30A to 30C.

The DC-DC converter 44 may be replaced with an alternator. In this case, the alternator may be provided on the upper rotating body 3 and generate electricity using the power of the pump motor 12. As in the case of the DC-DC converter 44, the power generated by the alternator is supplied to the battery 46, where it is charged (stored) in the battery 46, or supplied to electrical devices that are driven by the power of the battery 46, such as the controllers 30A to 30C.

The battery 46 is provided on the upper rotating body 3 and has a relatively low output voltage (e.g., 24 volts). The battery 46 supplies power to electrical equipment other than the electric drive system that requires relatively high power (e.g., controllers 30A-30C and air conditioning unit 80, etc.). The battery 46 is, for example, a lead-acid battery or a lithium-ion battery, and is charged with the output power of the DC-DC converter 44 as described above.

The cooling circuit 60 cools the electrical drive system equipment, etc. For example, as shown in FIG. 3, the equipment to be cooled by the cooling circuit 60 includes the pump motor 12, the inverter unit 18, the power storage device 19, the slewing drive device 20, the DC-DC converter 44, etc.

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

The radiator 62 cools the refrigerant (e.g., coolant) 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 circulates the refrigerant in the cooling circuit 60 by sucking the refrigerant from the refrigerant flow path 66F and discharging it into the refrigerant flow path 66A.

The refrigerant flow path 66A connects the water pump 64 and the slewing drive device 20, and allows the refrigerant discharged from the water pump 64 to flow into the refrigerant flow path inside the slewing drive device 20. This allows the slewing motor 21 and other components inside the slewing drive device 20 to be cooled by the refrigerant. The refrigerant that flows through the inside of the slewing drive device 20 flows out into the refrigerant flow path 66B.

The refrigerant flow path 66B connects the slewing drive device 20 and the power storage device 19, and allows the refrigerant flowing out of the slewing drive device 20 to flow into the refrigerant flow path inside the power storage device 19. This allows the power storage device 19 to be cooled by the refrigerant. The refrigerant that flows through the inside of the power storage device 19 flows out into the refrigerant flow path 66C.

The refrigerant flow paths 66C, 66C1, and 66C2 connect the power storage device 19 to the inverter unit 18 and the DC-DC converter 44, and allow the refrigerant flowing out of the power storage device 19 to flow into the refrigerant flow paths inside the inverter unit 18 and the DC-DC converter 44. Specifically, the refrigerant flow path 66C, one end of which is connected to the power storage device 19, branches into the refrigerant flow paths 66C1 and 66C2 at the other end, and the refrigerant flow paths 66C and 66C2 are connected to the inverter unit 18 and the DC-DC converter 44, respectively. This allows the inverters 18A and 18B and the DC-DC converter 44 included in the inverter unit 18 to be cooled. The refrigerant that flows through the inside of the inverter unit 18 flows out into the refrigerant flow path 66D1. The refrigerant that flows through the inside of the DC-DC converter 44 flows out into the refrigerant flow path 66D2.

The refrigerant flow paths 66D, 66D1, and 66D2 connect the inverter unit 18 and the DC-DC converter 44 to the pump motor 12, and allow the refrigerant flowing out from the inverter unit 18 and the DC-DC converter 44 to flow into the refrigerant flow paths inside the pump motor 12. Specifically, the refrigerant flow paths 66D1 and 66D2, one end of which is connected to the inverter unit 18 and the DC-DC converter 44, respectively, merge with one end of the refrigerant flow path 66D, and the other end of the refrigerant flow path 66D is connected to the pump motor 12. This allows the pump motor 12 to be cooled by the refrigerant. The refrigerant that has flowed through the inside of the pump motor 12 flows out into the refrigerant flow path 66E.

When a power conversion device is provided between the power storage device 19 and the DC bus 110, the power conversion device may be cooled by the cooling circuit 60. In this case, the power conversion device may be arranged, for example, in parallel with the inverter unit 18 and the DC-DC converter 44 in the cooling circuit 60, and may be cooled by the refrigerant flowing out from the power storage device 19. The DC-DC converter 44 may also be air-cooled. In this case, the refrigerant flow paths 66C2, 66D2 are omitted.

The refrigerant flow path 66E connects the pump motor 12 and the radiator 62, and supplies the refrigerant flowing out from the pump motor 12 to the radiator 62. This allows the radiator to cool the refrigerant whose temperature has risen by cooling various devices in the electric drive system, and the radiator can once again cool the various devices in the electric drive system.

The refrigerant flow path 66F connects between 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 through the cooling circuit 60.

The oil cooler 70 is provided, for example, in the return oil passage between the control valve 17 and the hydraulic oil tank T, and cools the hydraulic oil of the hydraulic drive system. Specifically, the oil cooler 70 exchanges heat between the surrounding air and the hydraulic oil flowing through it, thereby cooling the hydraulic oil.

The air conditioner 80 adjusts the temperature, humidity, etc., inside the cabin 10. The air conditioner 80 runs on power supplied from, for example, a DC-DC converter 44 or a battery 46. The air conditioner 80 is, for example, a heat pump type for both heating and cooling, and includes a heat pump cycle 82.

The air conditioner 80 may include, for example, a refrigeration cycle and a heater for heating, instead of the heat pump cycle 82. The heater for heating may be, for example, a PTC (Positive Temperature Coefficient) heater or a combustion heater.

As shown in FIG. 4, the heat pump cycle 82 includes a compressor 82A, a condenser 82B, an expansion valve 82C, and an evaporator 82D.

Note that the arrows in Figure 4 indicate the flow of refrigerant when the air conditioner 80 is in cooling operation, and the flow of refrigerant is in the opposite direction when the air conditioner 80 is in heating operation.

The compressor 82A compresses the refrigerant in the heat pump cycle 82. The compressor 82A includes, for example, an internal electric motor and an inverter circuit that drives the electric motor, and is electrically driven by power supplied from the power storage device 19. The refrigerant compressed by the compressor 82A is sent to the condenser 82B during cooling operation of the air conditioner 80, and is sent to the evaporator 82D during heating operation of the air conditioner 80.

The compressor 82A may also be configured to be mechanically driven by the pump motor 12.

When the air conditioner 80 is in cooling operation, the condenser 82B cools the refrigerant in a gaseous state that has been compressed by the compressor 82A and has a relatively high temperature. Specifically, the condenser 82B cools the refrigerant by dissipating heat from the refrigerant to the outside air through heat exchange between the refrigerant flowing inside the condenser 82B and the outside air. The refrigerant cooled by the condenser 82B changes to a liquid state.

In addition, when the air conditioner 80 is in heating operation, the condenser 82B absorbs heat from the outside air through heat exchange between the refrigerant flowing inside and the outside air, and raises the temperature of the refrigerant that has been reduced in pressure through the expansion valve 82C and lowered to a relatively low temperature.

The expansion valve 82C rapidly reduces the pressure of the refrigerant flowing through it, lowering the temperature of the refrigerant. During cooling operation of the air conditioner 80, the expansion valve 82C rapidly reduces the pressure of the liquid, high-pressure refrigerant sent from the condenser 82B, lowering the temperature. During heating operation of the air conditioner 80, the expansion valve 82C rapidly reduces the pressure of the liquid, high-pressure refrigerant sent from the evaporator 82D, lowering the temperature.

The evaporator 82D exchanges heat between the refrigerant flowing inside and the air sent from the air conditioner 80 into the cabin 10. During cooling operation of the air conditioner 80, the evaporator 82D cools the air sent into the cabin 10 by the relatively low-temperature refrigerant (gas-liquid mixed state) sent from the expansion valve 82C removing heat from the air. During heating operation of the air conditioner 80, the evaporator 82D warms the air sent into the cabin 10 by the air removing heat from the relatively high-temperature refrigerant (gaseous state) sent from the compressor 82A.

The fan 90 operates under the control of the control device 30 (e.g., controller 30A) and blows air toward a specific device (hereinafter, "heat exchange device") that exchanges heat with the outside air. The fan 90 operates with power supplied from, for example, the DC-DC converter 44 or the battery 46.

For example, as shown in FIG. 3, the fan 90 may blow air toward the radiator 62 to cool the radiator 62. This allows air capable of exchanging heat with the refrigerant flowing through the radiator 62 to be continuously supplied around the radiator 62, thereby increasing the degree to which the radiator 62 cools the refrigerant.

Furthermore, the fan 90 may blow air toward the oil cooler 70 to cool it, as shown in FIG. 2, for example. This allows air capable of exchanging heat with the hydraulic oil flowing through the oil cooler 70 to be continuously supplied around the oil cooler 70, thereby increasing the degree to which the hydraulic oil is cooled by the oil cooler 70.

Furthermore, the fan 90 may blow air toward the condenser 82B, for example, as shown in FIG. 4, to cool or heat the condenser 82B. This allows air capable of exchanging heat with the refrigerant flowing through the condenser 82B to be continuously supplied around the condenser 82B, thereby increasing the degree to which the refrigerant is cooled or heated by the condenser 82B.

[First example of fan control method]
Next, a first example of a method for controlling the fan 90 will be described with reference to FIGS.

<Layout of heat exchanger and fan>
First, the arrangement of the heat exchanger and the fan 90 according to this embodiment will be described.

Figures 5 and 6 are a front view and a side view showing a first example of the arrangement of the radiator 62, the oil cooler 70, the condenser 82B, and the fan 90. For convenience, the arrangement will be explained below using the directions in the figures (up, down, left, right, front, and rear).

The radiator 62, oil cooler 70, condenser 82B, and fan 90 are provided, for example, on the left rear side of the upper rotating body 3.

As shown in Figures 5 and 6, the radiator 62 and the oil cooler 70 are each of the downflow type, with tanks located at both ends in the vertical direction. The radiator 62 and the oil cooler 70 have a vertically elongated rectangular shape that is longer in the vertical direction than in the horizontal direction, and are arranged side by side.

The condenser 82B has a horizontally elongated rectangular shape that is longer left-to-right than it is up-down, and is positioned adjacent to and below the radiator 62 and oil cooler 70.

Fans 90 include fans 90A to 90F.

Fans 90A and 90B are disposed behind the radiator 62 and blow air to the radiator 62 by drawing air from the front to the rear. Fans 90A and 90B are disposed one above the other, with fan 90A on the upper side and fan 90B on the lower side. Hereinafter, fans 90A and 90B may be referred to collectively or individually as "radiator fans."

Fans 90C and 90D are disposed behind the oil cooler 70 and blow air into the oil cooler 70 by drawing air from the front to the rear. Fans 90C and 90D are disposed one above the other, with fans 90C and 90C on the upper side and fan 90D on the lower side. Hereinafter, fans 90C and 90D may be referred to collectively or individually as "oil cooler fans."

Fans 90E and 90F are positioned behind condenser 82B and blow air into condenser 82B by drawing air from front to back. Fans 90E and 90F are positioned side by side, with fan 90E on the right side and fan 90F on the left side.

In this way, in this example, multiple fans 90 (two in this example) are installed that can blow air to one heat exchange device (an example of a specified device).

As a result, as described below, the control device 30 can stop only some of the fans 90 or operate them at a relatively low rotation speed depending on the degree of heat exchange (cooling or heating) required by the heat exchange device. Therefore, the control device 30 can more finely adjust the degree of heat exchange of the heat exchanger.

In particular, the amount of heat generated by the electric drive system in this embodiment is smaller than the amount of heat generated by the engine in an excavator equipped with an engine, and the degree of cooling required for the radiator 62 may be relatively low. Therefore, if one radiator fan is rotated at a relatively high rotational speed to cool the radiator 62, the degree of cooling of the radiator 62 may be higher than necessary, which may lead to overcooling or waste of current consumption.

In contrast, in this example, the control device 30 controls multiple fans 90A, 90B that can blow air to the radiator 62, and can more appropriately control the degree of cooling of the radiator 62, as described below.

In addition, three or more fans 90 capable of blowing air to one heat exchanger (radiator 62, oil cooler 70, condenser 82B) may be installed. The same applies to the second example described below.

In this example, a dedicated fan 90 capable of blowing air to the heat exchanger is installed for each of the multiple heat exchange devices.

This improves heat exchange efficiency (cooling efficiency and heating efficiency) compared to when a single fan 90 blows air to multiple heat exchange devices.

In this example, multiple fans 90 capable of blowing air to the heat exchange devices are installed for each of the multiple heat exchange devices.

As a result, the control device 30 can stop only some of the fans 90 or operate them at a relatively low rotation speed for each of multiple heat exchange devices, depending on the degree of heat exchange required for the heat exchange device.

The number of radiator fans may be one. The same may be true for the oil cooler fan and condenser fan.

<Control process of the control device regarding the radiator fan>
Next, the control process for the radiator fan by the control device 30 will be described with reference to Figures 7 and 8. In this example, the description will be given on the assumption that the radiator fan rotates at a relatively high rotation speed (e.g., the maximum allowable rotation speed) when it is in operation. The same applies to the second example (Figures 14 and 15) described below.

Figures 7 and 8 are flow charts that show a first example of the control process for the radiator fan by the control device 30 (controller 30A). This flow chart is repeatedly executed at a predetermined control period, for example, during operation from when the shovel is started (e.g., when the key switch is turned ON) to when it is stopped (e.g., when the key switch is turned OFF). The same may be true for the flow charts in Figures 9 and 10, the flow chart in Figure 11, the flow charts in Figures 14 and 15, the flow charts in Figures 16 and 17, and the flow chart in Figure 18.

As shown in FIG. 7, in step S102, controller 30A determines whether or not the radiator fan (at least one of fans 90A and 90B) is operating. If the radiator fan (both fans 90A and 90B) is not operating, controller 30A proceeds to step S104, and if the radiator fan is operating, controller 30A proceeds to step S110.

In step S104, the controller 30A determines whether the temperature of at least one of the electrical drive devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth11 based on the detection signal of the temperature sensor 54. The threshold value TDth11 is, for example, a suitable value that is predefined for each electrical drive device to be cooled by the cooling circuit 60. In other words, the threshold value TDth11 for any two electrical drive devices to be cooled by the cooling circuit 60 may be different from each other, and the controller 30A performs the determination in this step using the threshold value TDth11 value suitable for each electrical drive device to be cooled by the cooling circuit 60. The same applies to the threshold values TDth12, TDth21, and TDth22 described below. If the temperature of at least one of the electrical drive devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth11, the controller 30A proceeds to step S106, and if the temperature does not exceed the threshold value TDth11, the controller 30A ends the processing of this flowchart.

In step S106, the controller 30A determines whether the temperature of at least one of the electrical drive system devices to be cooled by the cooling circuit 60 exceeds the threshold value TDth12 (>TDth11) based on the detection signal of the temperature sensor 54. If the temperature of at least one of the electrical drive system devices to be cooled by the cooling circuit 60 does not exceed the threshold value TDth12, the controller 30A proceeds to step S108, and if it does exceed the threshold value TDth12, the controller 30A proceeds to step S114.

In step S108, the controller 30A sets only one of the radiator fans to be in operation. Specifically, the controller 30A starts operation of either the fan 90A or the fan 90B. The fan to be started may be the fan 90A or the fan 90B. This allows the controller 30A to start operation of one of the radiator fans in a situation where the temperature of the electrically driven equipment to be cooled by the cooling circuit 60 is relatively high, thereby increasing the degree of cooling of the radiator 62. Therefore, the controller 30A can increase the degree of cooling of the refrigerant that flows through the radiator 62 and is cooled, thereby decreasing the temperature of the electrically driven equipment.

When the processing of step S108 is completed, the controller 30A completes the processing of this flowchart.

On the other hand, in step S110, controller 30A determines whether or not only one radiator fan is in operation. If only one radiator fan is in operation, controller 30A proceeds to step S112, and if more than one radiator fan is in operation (i.e., both radiator fans are in operation), controller 30A proceeds to step S120.

In step S112, the controller 30A determines whether or not the temperature of at least one of the devices in the electric drive system to be cooled by the cooling circuit 60 exceeds the threshold value TDth12 based on the detection signal of the temperature sensor 54. If the temperature of at least one of the devices in the electric drive system to be cooled by the cooling circuit 60 exceeds the threshold value TDth12, the controller 30A proceeds to step S114, and if the temperature does not exceed the threshold value TDth12, the controller 30A proceeds to step S116.

In step S114, the controller 30A operates both radiator fans. For example, when the judgment condition in step S106 is met (YES in step S106), the controller 30A outputs a control command to both fans 90A and 90B to start operating them. Also, when the judgment condition in step S112 is met (YES in step S112), the controller 30A outputs a control command to the other of the fans 90A and 90B, which is different from the one currently operating, to start operating them. This allows the controller 30A to drive both radiator fans and further increase the cooling degree of the radiator 62 when the temperature of the electric drive system equipment to be cooled by the cooling circuit 60 is very high. Therefore, the controller 30A can further increase the cooling degree of the refrigerant that is flowing through the radiator 62 and cooled, thereby lowering the temperature of the electric drive system equipment.

When the processing of step S114 is completed, the controller 30A completes the processing of this flowchart.

On the other hand, in step S116, the controller 30A determines whether the temperatures of all the electrically driven devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth21 (≦TDth11) based on the detection signal of the temperature sensor 54. If the temperatures of all the electrically driven 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 S118, and if the temperatures are not equal to or lower than the threshold value TDth21, the controller 30A ends the processing of this flowchart.

In step S118, the controller 30A outputs a control command to one of the operating radiator fans to stop it. That is, the controller 30A stops both radiator fans. This allows the controller 30A to stop both radiator fans in response to a situation in which the temperature of the electrically driven equipment to be cooled by the cooling circuit 60 has dropped to a very low state. Therefore, the controller 30A can prevent excessive cooling of the radiator 62, and can prevent the radiator fan from continuing to operate unnecessarily, thereby reducing power consumption.

When the processing of step S118 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, as shown in FIG. 8, in step S120, the controller 30A determines whether the temperatures of all the electrically driven devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth22 based on the detection signal of the temperature sensor 54 (TDth11<TDth22≦TDth12). If the temperatures of all the electrically driven devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth22, the controller 30A proceeds to step S122, and if the temperatures are not equal to or lower than the threshold value TDth22, the controller 30A ends the processing of this flowchart.

In step S122, the controller 30A determines whether the temperatures of all the electrically driven devices to be cooled by the cooling circuit 60 are equal to or lower than the threshold value TDth21 based on the detection signal of the temperature sensor 54. If the temperatures of all the electrically driven 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 S124, and if the temperatures are not equal to or lower than TDth21, the controller 30A proceeds to step S126.

In step S124, the controller 30A outputs a control command to both radiator fans to stop them. That is, the controller 30A stops both radiator fans. This provides the same effect as in step S120.

When the processing of step S124 is completed, the controller 30A ends the processing of this flowchart.

Meanwhile, in step S126, the controller 30A outputs a control command to one of the radiator fans to stop it. That is, the controller 30A sets the state in which only one of the fans is operating. This allows the controller 30A to stop one of the radiator fans in accordance with the situation in which the temperature of the electrically driven equipment to be cooled by the cooling circuit 60 has dropped to a relatively low state. Therefore, the controller 30A can prevent excessive cooling of the radiator 62, and can also prevent the radiator fan from continuing to operate unnecessarily, thereby reducing power consumption.

In addition, the controller 30A may vary the rotation speed of the radiator fan between a relatively low rotation speed and a relatively high rotation speed according to the temperature of the electric drive system equipment to be cooled by the cooling circuit 60. For example, when the temperature of at least one of the electric drive system equipment to be cooled by the cooling circuit 60 exceeds the threshold value TDth11, the controller 30A may control one of the radiator fans so that the rotation speed becomes higher within a certain range as the amount of the excess increases. And, when the temperature of at least one of the electric drive system equipment to be cooled by the cooling circuit 60 exceeds the threshold value TDth11 and the amount of the excess exceeds a certain range, the controller 30A may rotate one of the radiator fans at the maximum allowable rotation speed regardless of the amount of the excess. Also, for example, when the temperature of at least one of the electric drive system equipment to be cooled by the cooling circuit 60 exceeds the threshold value TDth12, the controller 30A may control the other radiator fan so that the rotation speed becomes higher within a certain range as the amount of the excess increases. If the temperature of at least one of the devices in the electric drive system to be cooled by the cooling circuit 60 exceeds the threshold TDth12 and the amount by which the temperature exceeds the threshold exceeds a certain range, the controller 30A may rotate the other radiator fan at the maximum allowable rotation speed, regardless of the amount by which the temperature exceeds the threshold TDth12.

Thus, in this example, under the control of controller 30A, some of the multiple radiator fans (fans 90A and 90B) may be in a stopped state or in an operating state with a relatively slower rotation speed than the other radiator fans.

This allows the controller 30A to stop some of the radiator fans or operate them at a relatively low rotation speed depending on the degree of cooling required for the radiator 62. Therefore, the controller 30A can prevent excessive cooling of the radiator 62 and can also reduce power consumption caused by the operation of the radiator fans.

In addition, in this example, when the degree of cooling required for the radiator 62 is relatively high, the controller 30A controls the multiple radiator fans so that all of the radiator fans operate at a relatively high rotation speed. On the other hand, when the degree of cooling required for the radiator 62 is relatively low, the controller 30A controls the multiple radiator fans so that only some of the radiator fans are stopped or rotate at a slower speed than the other fans.

Specifically, when the temperature of the electrically driven equipment (an example of the cooled equipment) cooled through the refrigerant (an example of the cooled fluid) flowing through the inside of the radiator 62 is relatively high, the controller 30A controls the multiple radiator fans so that all of them operate at a relatively high rotation speed. On the other hand, when the temperature of the electrically driven equipment cooled through the refrigerant flowing through the inside of the radiator 62 is relatively low, the controller 30A controls the multiple radiator fans so that only some of the radiator fans are stopped or have a relatively slower rotation speed than the other radiator fans.

As a result, the controller 30A can specifically stop some of the multiple radiator fans or operate them at a relatively low rotation speed depending on the level of cooling required for the radiator 62.

<Control process of the control device regarding the oil cooler fan>
Next, the control process for the oil cooler fan by the control device 30 will be described with reference to Figs. 9 and 10. In this example, the description will be given on the assumption that the oil cooler fan rotates at a relatively high rotation speed (e.g., the maximum allowable rotation speed) when it is in operation. The same applies to the second example (Figs. 16 and 17) described below.

Figures 9 and 10 are flow charts that show a first example of the control process for the oil cooler fan by the control device 30 (controller 30A).

As shown in FIG. 9, in step S202, controller 30A determines whether the oil cooler fan (at least one of fans 90C and 90D) is operating. If the oil cooler fan (both fans 90C and 90D) is not operating, controller 30A proceeds to step S204, and if the oil cooler fan is operating, controller 30A proceeds to step S210.

In step S204, the controller 30A determines whether the hydraulic oil temperature has exceeded the threshold value TOLth11 based on the detection signal of the oil temperature sensor 56. The threshold value TOLth11 is, for example, a predetermined adaptation value. The same applies to the threshold values TOLth12, TOLth21, and TOLth22 described below. If the hydraulic oil temperature has exceeded the threshold value TOLth11, the controller 30A proceeds to step S206, and if the hydraulic oil temperature has not exceeded the threshold value TOLth11, the controller 30A ends the processing of this flowchart.

In step S206, the controller 30A determines whether the hydraulic oil temperature has exceeded the threshold TOLth12 (>TOLth11) based on the detection signal of the oil temperature sensor 56. If the hydraulic oil temperature has not exceeded the threshold TOLth12, the controller 30A proceeds to step S208, and if the hydraulic oil temperature has exceeded the threshold TOLth12, the controller 30A proceeds to step S214.

In step S208, the controller 30A sets up a state in which only one of the oil cooler fans is operating. Specifically, the controller 30A starts operation of either the fan 90C or the fan 90D. The fan to be started may be the fan 90C or the fan 90D. This allows the controller 30A to start operation of one of the oil cooler fans in a situation in which the hydraulic oil temperature is relatively high, thereby increasing the degree of cooling of the oil cooler 70. Therefore, the controller 30A can increase the degree of cooling of the hydraulic oil that is cooled by flowing through the oil cooler 70, and reduce the temperature of the hydraulic oil.

When the processing of step S208 is completed, the controller 30A completes the processing of this flowchart.

On the other hand, in step S210, the controller 30A determines whether or not only one oil cooler fan is in operation. If only one oil cooler fan is in operation, the controller 30A proceeds to step S212, and if more than one oil cooler fan is in operation (i.e., both oil cooler fans are in operation), the controller 30A proceeds to step S220.

In step S212, the controller 30A determines whether the hydraulic oil temperature exceeds the threshold TOLth12 based on the detection signal of the oil temperature sensor 56. If the hydraulic oil temperature exceeds the threshold TOLth12, the controller 30A proceeds to step S214, and if the hydraulic oil temperature does not exceed the threshold TOLth12, the controller 30A proceeds to step S216.

In step S214, the controller 30A operates both oil cooler fans. For example, when the judgment condition in step S206 is met (YES in step S206), the controller 30A outputs a control command to both fans 90C and 90D to start operating them. Also, when the judgment condition in step S212 is met (YES in step S212), the controller 30A outputs a control command to the other of the fans 90C and 90D that is different from the one currently operating, to start operating them. This allows the controller 30A to drive both oil cooler fans in a situation where the hydraulic oil temperature is very high, thereby further increasing the degree of cooling of the oil cooler 70. Therefore, the controller 30A can further increase the degree of cooling of the hydraulic oil that is cooled by flowing through the oil cooler 70, thereby lowering the hydraulic oil temperature.

When the processing of step S214 is completed, the controller 30A completes the processing of this flowchart.

On the other hand, in step S216, the controller 30A determines whether the hydraulic oil temperature is equal to or lower than the threshold TOLth21 (≦TOLth11) based on the detection signal of the oil temperature sensor 56. If the hydraulic oil temperature is equal to or lower than the threshold TOLth21, the controller 30A proceeds to step S218, and if the hydraulic oil temperature is not equal to or lower than the threshold TOLth21, the controller 30A ends the processing of this flowchart.

In step S218, the controller 30A outputs a control command to one of the oil cooler fans that is in operation to stop it. That is, the controller 30A stops both oil cooler fans. This allows the controller 30A to stop both oil cooler fans in response to a situation in which the operating oil temperature has dropped to a very low state. Therefore, the controller 30A can prevent excessive cooling of the oil cooler 70, and can also prevent the oil cooler fan from continuing to operate unnecessarily, thereby reducing power consumption.

When the processing of step S218 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, as shown in FIG. 10, in step S220, the controller 30A determines whether the hydraulic oil temperature is equal to or lower than the threshold value TOLth22 based on the detection signal of the oil temperature sensor 56 (TOLth11<TOLth22≦TOLth12). If the hydraulic oil temperature is equal to or lower than the threshold value TOLth22, the controller 30A proceeds to step S222, and if the hydraulic oil temperature is not equal to or lower than the threshold value TOLth22, the controller 30A ends the processing of this flowchart.

In step S222, 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 TOLth21 based on the detection signal of the oil temperature sensor 56. If the hydraulic oil temperature is equal to or lower than the threshold TOLth21, the controller 30A proceeds to step S224, and if the hydraulic oil temperature is not equal to or lower than TOLth21, the controller 30A proceeds to step S226.

In step S224, the controller 30A outputs a control command to both oil cooler fans to stop them. That is, the controller 30A stops both oil cooler fans. This provides the same effect as in step S220.

When the processing of step S224 is completed, the controller 30A ends the processing of this flowchart.

Meanwhile, in step S226, the controller 30A outputs a control command to one of the oil cooler fans to stop it. That is, the controller 30A sets the state in which only one of the fans is operating. This allows the controller 30A to stop one of the oil cooler fans in accordance with the situation in which the hydraulic oil temperature has dropped to a relatively low state. Therefore, the controller 30A can prevent excessive cooling of the oil cooler 70, and can also prevent the oil cooler fan from continuing to operate unnecessarily, thereby reducing power consumption.

In addition, the controller 30A may vary the rotation speed of the oil cooler fan between a relatively low rotation speed and a relatively high rotation speed according to the high and low hydraulic oil temperatures. For example, when the hydraulic oil temperature exceeds the threshold TOLth11, the controller 30A may control one of the oil cooler fans so that the rotation speed becomes higher within a certain range as the hydraulic oil temperature exceeds the threshold TOLth11. When the hydraulic oil temperature exceeds the threshold TOLth11 and the amount by which the hydraulic oil temperature exceeds a certain range, the controller 30A may rotate one of the oil cooler fans at the maximum allowable rotation speed regardless of the amount by which the hydraulic oil temperature exceeds the threshold TOLth11. Also, for example, when the hydraulic oil temperature exceeds the threshold TOLth12, the controller 30A may control the other oil cooler fan so that the rotation speed becomes higher within a certain range as the amount by which the hydraulic oil temperature exceeds the threshold TOLth12. If the hydraulic oil temperature exceeds the threshold TOLth12 and the amount by which it exceeds the threshold TOLth12 exceeds a certain range, the controller 30A may rotate the other oil cooler fan at the maximum allowable rotation speed, regardless of the amount by which it exceeds the threshold TOLth12.

Thus, in this example, under the control of the controller 30A, some of the multiple oil cooler fans (fans 90C, 90D) may be in a stopped state or may have a relatively slower rotation speed than the other oil cooler fans.

This allows the controller 30A to stop some of the oil cooler fans or operate them at a relatively low rotation speed depending on the degree of cooling required for the oil cooler 70. Therefore, the controller 30A can prevent excessive cooling of the oil cooler 70 and can also reduce power consumption caused by the operation of the oil cooler fans.

In addition, in this example, when the degree of cooling required for the oil cooler 70 is relatively high, the controller 30A controls the multiple oil cooler fans so that all of the oil cooler fans operate at a relatively high rotation speed. On the other hand, when the degree of cooling required for the oil cooler 70 is relatively low, the controller 30A controls the multiple oil cooler fans so that only some of the oil cooler fans are stopped or have a lower rotation speed than the other fans.

Specifically, when the temperature (hydraulic oil temperature) of the hydraulic oil (one example of a cooled fluid) flowing inside the oil cooler 70 is relatively high, the controller 30A controls the multiple oil cooler fans so that all of them operate at a relatively high rotation speed. On the other hand, when the temperature of the hydraulic oil flowing inside the oil cooler 70 is relatively low, the controller 30A controls the multiple oil cooler fans so that only some of the oil cooler fans are stopped or have a relatively slower rotation speed than the other oil cooler fans.

As a result, the controller 30A can specifically stop some of the multiple oil cooler fans or operate them at a relatively low rotation speed depending on the level of cooling required for the oil cooler 70.

<Control process of the control device regarding the condenser fan>
Next, the control process for the condenser fan by the control device 30 will be described with reference to Fig. 11. In this example, the description will be given on the assumption that the radiator fan rotates at a relatively high rotation speed (e.g., the maximum allowable rotation speed) when it is operated. The same applies to the second example (Fig. 18) described below.

Figure 11 is a flowchart that shows a first example of the control process for the condenser fan by the control device 30 (controller 30A).

As shown in FIG. 11, in step S302, controller 30A determines whether or not the condenser fans (fans 90E and 90F) are operating. If the condenser fans are not operating, controller 30A proceeds to step S304, and if they are operating, controller 30A proceeds to step S308.

In step S304, the controller 30A determines whether the compressor 82A has started operating. If the compressor 82A has started operating, the controller 30A proceeds to step S306, and if the compressor 82A is not operating, the controller 30A ends the processing of this flowchart.

In step S306, controller 30A outputs a control command to both condenser fans, causing both condenser fans to start operating.

When the processing of step S306 is completed, controller 30A ends the processing of this flowchart.

On the other hand, in step S308, the controller 30A determines whether the compressor 82A has stopped. If the compressor 82A has stopped, the controller 30A proceeds to step S310, and if the compressor 82A has not stopped, the controller 30A ends the processing of this flowchart.

In step S310, controller 30A outputs a control command to both condenser fans to stop both condenser fans.

When the processing of step S310 is completed, controller 30A ends the processing of this flowchart.

Thus, in this example, the controller 30A operates the condenser fan when the compressor 82A is operating, and stops the condenser fan when the compressor 82A is not operating.

As a result, the controller 30A can operate the condenser fan when heat exchange in the condenser 82B is required, and can stop the condenser fan when heat exchange in the condenser 82B is not required. This makes it possible to reduce power consumption due to the operation of the condenser fan.

[Second Example of Fan Control Method]
Next, a second example of a method for controlling the fan 90 will be described with reference to FIGS.

<Layout of heat exchanger and fan>
First, the arrangement of the heat exchanger and the fan 90 according to this embodiment will be described.

Figures 12 and 13 are a front view and a side view showing a second example of the arrangement of the radiator 62, the oil cooler 70, the condenser 82B, and the fan 90. For convenience, the arrangement will be explained below using the directions in the figures (up, down, left, right, front, and rear).

As shown in Figures 12 and 13, the radiator 62 and the oil cooler 70 are of the downflow type, as in the first example (Figures 5 and 6) described above, and tanks are arranged at both ends in the vertical direction. The radiator 62 and the oil cooler 70 have a vertically elongated rectangular shape that is longer in the vertical direction than in the horizontal direction, and are arranged side by side.

The condenser 82B has a horizontally elongated rectangular shape that is longer in the left-right direction than in the up-down direction, similar to the first example described above. Unlike the first example described above, the condenser 82B is disposed adjacent to the front of the radiator 62 and the oil cooler 70. Specifically, the condenser 82B is disposed so that its approximately left half covers the front of approximately the upper half of the heat exchange section of the radiator 62, and its approximately right half covers the front of approximately the upper half of the heat exchange section of the oil cooler 70.

Fans 90 include fans 90G to 90J.

Fans 90G, 90H are disposed behind the radiator 62 and blow air to the radiator 62 by drawing air from front to rear. Fans 90G, 90H are disposed one above the other, with fan 90G on the upper side and fan 90H on the lower side. Hereinafter, fans 90G, 90H may be referred to collectively or individually as "radiator fans."

Fans 90I, 90J are disposed behind the oil cooler 70 and blow air into the oil cooler 70 by drawing air from the front to the rear. Fans 90I, 90J are disposed one above the other, with fan 90C on the upper side and fan 90D on the lower side. Hereinafter, fans 90C, 90D may be referred to collectively or individually as "oil cooler fans."

As described above, the fan 90G is disposed in approximately the upper half of the heat exchange section of the radiator 62, i.e., behind the portion of the heat exchange section of the radiator 62 where the condenser 82B covers the front. Therefore, the fan 90G can blow air to both the condenser 82B and the radiator 62 by sucking in air from the front to the rear.

As described above, the fan 90I is disposed in approximately the upper half of the heat exchange section of the oil cooler 70, i.e., behind the portion of the heat exchange section of the oil cooler 70 where the condenser 82B covers the front. Therefore, the fan 90I can blow air to both the condenser 82B and the radiator 62 by sucking in air from the front to the rear.

Hereinafter, fans 90G and 90I may be referred to collectively or individually as "condenser fans." Fan 90G may be referred to as the "shared radiator fan," and fan 90I may be referred to as the "shared oil cooler fan." Fan 90H may be referred to as the "non-shared radiator fan," and fan 90J may be referred to as the "non-shared oil cooler fan."

In this way, in this example, similar to the first example described above, multiple fans 90 (two in this example) capable of blowing air to one heat exchange device are installed. Also, in this example, similar to the first example described above, multiple fans 90 capable of blowing air to the heat exchange devices are installed for each of the multiple heat exchange devices. This provides the same actions and effects as the first example described above.

In addition, in this example, fans 90G, 90I are shared between the condenser 82B and the radiator 62 and the oil cooler 70, respectively. This allows the number of fans 90 to be relatively small.

<Control process of the control device regarding the radiator fan>
Next, the control process for the radiator fan by the control device 30 will be described with reference to Figs.

Figures 14 and 15 are flow charts that show a second example of the control process for the radiator fan by the control device 30 (controller 30A). In the following, flag F1 indicates whether the operating conditions for the shared radiator fan (fan 90G) related to the degree of cooling required for the radiator 62 are met. The explanation will proceed on the assumption that flag F1 is initially set to "0" and is initialized to "0" when the excavator is started.

As shown in FIG. 14, in step S402, controller 30A determines whether the non-shared radiator fan (fan 90H) is operating. If the non-shared radiator fan is not operating, controller 30A proceeds to step S404, and if the non-shared radiator fan is operating, controller 30A proceeds to step S410.

Step S404 is the same as the processing of step S104 in FIG. 7. If the judgment condition is met, the controller 30A proceeds to step S406, and if the judgment condition is not met, the controller 30A ends the processing of this flowchart.

Step S406 is the same as the processing of step S106 in FIG. 7. If the determination condition is not met, controller 30A proceeds to step S408, and if the determination condition is met, controller 30A proceeds to step S414.

In step S408, the controller 30A outputs a control command to the non-shared radiator fan to start operating only the non-shared oil cooler fan. As a result, the controller 30A can operate the shared radiator fan with priority, for example, regardless of the degree of cooling required for the condenser 82B, and prevent the condenser 82B from being overcooled or overheated. In addition, by operating the shared radiator fan with priority, the controller 30A can prevent the air that has passed through the condenser 82B from being blown to the radiator 62, resulting in a relative decrease in the degree of cooling of the radiator 62.

When the processing of step S408 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S410, the controller 30A determines whether the flag F1 is "1", i.e., whether the operating conditions of the shared radiator fan related to the degree of cooling required for the radiator 62 are met. If the flag F1 is not "1", the controller 30A proceeds to step S412, and if the flag F1 is "1", the controller 30A proceeds to step S420.

Step S412 is the same as the processing of step S112 in FIG. 7. If the determination condition is met, the controller 30A proceeds to step S414, and if the determination condition is not met, the controller 30A proceeds to step S416.

In step S414, the controller 30A operates both radiator fans and sets the flag F1 to "1". For example, when both radiator fans are stopped, the controller 30A outputs a control command to both radiator fans to start them, and sets the flag F1 to "1". When both radiator fans are stopped, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is not satisfied (i.e., the flag F3 described below is "0") and the judgment condition of step S406 is satisfied. Also, when, for example, only the shared radiator fan is operating, the controller 30A outputs a control command to the non-shared radiator fan to start it, and sets the flag F1 to "1". When only the shared radiator fan is operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied (i.e., the flag F3 is "1") and the judgment condition of step S406 is satisfied. Also, for example, when only the non-shared radiator fan is operating, the controller 30A outputs a control command to the shared radiator fan to start operating. When only the non-shared radiator fan is operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is not satisfied (i.e., the flag F3 described below is "0") and the judgment condition of step S412 is satisfied. When both radiator fans are already operating, the controller 30A only performs the process of setting the flag F1 to "1". When both radiator fans are already operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied (i.e., the flag F3 is "1") and the judgment condition of step S412 is satisfied.

When the processing of step S414 is completed, the controller 30A ends the processing of this flowchart.

Step S416 is the same as step S116 in FIG. 7. If the determination condition is met, controller 30A proceeds to step S418; if the determination condition is not met, controller 30A ends the processing of this flowchart.

In step S418, controller 30A outputs a control command to the non-shared radiator fan to stop the non-shared radiator fan.

When the processing of step S418 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, as shown in FIG. 15, step S420 is the same as the processing of step S120 in FIG. 8. If the determination condition is met, the controller 30A proceeds to step S422, and if the determination condition is not met, the controller 30A ends the processing of this flowchart.

Step S422 is the same as the processing of step S122 in FIG. 8. If the determination condition is met, controller 30A proceeds to step S424, and if not, proceeds to step S430.

In step S424, the controller 30A determines whether the flag F3 is "1", i.e., whether the operating conditions of the common oil cooler fan related to the degree of heat exchange required for the condenser 82B are met. If the flag F3 is not "1", the controller 30A proceeds to step S426, and if the flag F3 is "1", the controller 30A proceeds to step S428.

In step S426, controller 30A outputs a control command to both radiator fans to stop them and sets flag F1 to "0."

When the processing of step S426 is completed, the controller 30A ends the processing of this flowchart.

Meanwhile, in step S428, controller 30A outputs a control command to the non-shared radiator fan to stop it, and sets flag F1 to "0". This allows controller 30A to continue operating the shared radiator fan even when the degree of cooling required for radiator 62 is very low in a situation where the degree of heat exchange required for condenser 82B is relatively high. This makes it possible to prevent a situation in which the degree of heat exchange required for condenser 82B is insufficient, resulting in a decrease in the cooling or heating performance of air conditioner 80.

When the processing of step S428 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S430, the controller 30A determines whether the flag F3 is "1", that is, whether the operating condition of the common oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied. If the flag F3 is not "1", the controller 30A proceeds to step S432, and if the flag F3 is "1", the controller 30A proceeds to step S434.

In step S432, controller 30A outputs a control command to the shared radiator fan to stop it and sets flag F1 to "0."

When the processing of step S432 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S434, controller 30A only performs the process of setting flag F3 to "1". This allows controller 30A to continue operating the shared radiator fan even when the degree of heat exchange required for condenser 82B is relatively high and the degree of cooling required for radiator 62 is relatively low. This makes it possible to prevent a situation in which the degree of heat exchange required for condenser 82B is insufficient, resulting in a decrease in the cooling or heating performance of air conditioner 80.

When the processing of step S434 is completed, the controller 30A ends the processing of this flowchart.

Thus, in this example, the multiple radiator fans include, among them, a shared radiator fan (an example of a shared fan) that is shared as part of the multiple condenser fans. Then, when the degree of heat exchange required for the radiator 62 (an example of a first device) is relatively low, the controller 30A preferentially operates the non-shared radiator fans other than the shared radiator fan among the multiple radiator fans. On the other hand, when the degree of heat exchange required for the radiator 62 is relatively high, the controller 30A operates the shared radiator fan in addition to the non-shared radiator fan.

This allows the controller 30A to suppress the impact on the degree of heat exchange of the condenser 82B that may occur when operating the radiator fan, based on the degree of cooling required for the radiator 62.

In addition, in this example, even if the condition for stopping the shared radiator fan based on the degree of heat exchange (degree of cooling) required for the radiator 62 is met while the shared radiator fan is operating, if the condition for stopping the shared fan based on the degree of heat exchange required for the condenser 82B (an example of a second device) is not met, the controller 30A continues operating the shared radiator fan.

This allows the controller 30A to prevent a situation in which the degree of heat exchange in the condenser 82B becomes insufficient, thereby affecting the air conditioning performance of the air conditioner 80.

The radiator 62, condenser 82B, and fan 90 may be arranged so that all of the multiple condenser fans are shared radiator fans. In this case, the controller 30A employs a similar control method to achieve the same effects and advantages.

<Control process of the control device regarding the oil cooler fan>
Next, the control process for the oil cooler fan by the control device 30 will be described with reference to Figs.

Figures 16 and 17 are flow charts that show a schematic diagram of a second example of the control process for the oil cooler fan by the control device 30 (controller 30A). In the following, flag F2 indicates whether the operating conditions for the shared oil cooler fan (fan 90I) related to the degree of cooling required for the oil cooler 70 are met. The explanation will proceed on the assumption that flag F2 is initially set to "0" and is initialized to "0" when the excavator is started.

As shown in FIG. 16, in step S502, controller 30A determines whether the non-shared oil cooler fan (fan 90J) is operating. If the non-shared oil cooler fan is not operating, controller 30A proceeds to step S504, and if the non-shared oil cooler fan is operating, controller 30A proceeds to step S510.

Step S504 is the same as the processing of step S204 in FIG. 9. If the judgment condition is met, the controller 30A proceeds to step S506, and if the judgment condition is not met, the controller 30A ends the processing of this flowchart.

Step S506 is the same as the processing of step S206 in FIG. 9. If the determination condition is not met, controller 30A proceeds to step S508, and if the determination condition is met, controller 30A proceeds to step S514.

In step S508, the controller 30A outputs a control command to the non-shared oil cooler fan to start operating only the non-shared oil cooler fan. This allows the controller 30A to operate the shared oil cooler fan preferentially, for example, regardless of the degree of cooling required for the condenser 82B, and to prevent the condenser 82B from being overcooled or overheated. Furthermore, by operating the shared oil cooler fan preferentially, the controller 30A can prevent the air that has passed through the condenser 82B from being blown to the oil cooler 70A, resulting in a relative decrease in the degree of cooling of the oil cooler 70A.

When the processing of step S508 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S510, the controller 30A determines whether the flag F2 is "1", i.e., whether the operating conditions of the shared oil cooler fan related to the degree of cooling required for the oil cooler 70 are met. If the flag F2 is not "1", the controller 30A proceeds to step S512, and if the flag F2 is "1", the controller 30A proceeds to step S520.

Step S512 is the same as the processing of step S212 in FIG. 9. If the determination condition is met, controller 30A proceeds to step S514, and if not, proceeds to step S516.

In step S514, the controller 30A operates both oil cooler fans and sets the flag F2 to "1". For example, when both oil cooler fans are stopped, the controller 30A outputs a control command to both oil cooler fans to start them, and sets the flag F2 to "1". When both oil cooler fans are stopped, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is not satisfied (i.e., the flag F3 described below is "0") and the judgment condition of step S506 is satisfied. Also, when, for example, only the shared oil cooler fan is operating, the controller 30A outputs a control command to the non-shared oil cooler fan to start them, and sets the flag F2 to "1". When only the shared oil cooler fan is operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied (i.e., the flag F3 is "1") and the judgment condition of step S506 is satisfied. Also, for example, when only the non-shared oil cooler fan is operating, the controller 30A outputs a control command to the shared oil cooler fan to start operating. When only the non-shared oil cooler fan is operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is not satisfied (i.e., the flag F3 described below is "0") and the judgment condition of step S512 is satisfied. When both oil cooler fans are already operating, the controller 30A only performs the process of setting the flag F2 to "1". When both oil cooler fans are already operating, this corresponds to the case where the operating condition of the shared oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied (i.e., the flag F3 is "1") and the judgment condition of step S512 is satisfied.

When the processing of step S514 is completed, the controller 30A ends the processing of this flowchart.

Step S516 is the same as step S216 in FIG. 9. If the determination condition is met, controller 30A proceeds to step S518; if the determination condition is not met, controller 30A ends the processing of this flowchart.

In step S518, controller 30A outputs a control command to the non-shared oil cooler fan to stop the non-shared oil cooler fan.

When the processing of step S518 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, as shown in FIG. 17, step S520 is the same as the processing of step S220 in FIG. 10. If the determination condition is met, the controller 30A proceeds to step S522, and if the determination condition is not met, the controller 30A ends the processing of this flowchart.

Step S522 is the same as the processing of step S222 in FIG. 10. If the determination condition is met, controller 30A proceeds to step S524, and if not, proceeds to step S530.

In step S524, the controller 30A determines whether the flag F3 is "1", i.e., whether the operating conditions of the common oil cooler fan related to the degree of heat exchange required for the condenser 82B are met. If the flag F3 is not "1", the controller 30A proceeds to step S526, and if the flag F3 is "1", the controller 30A proceeds to step S528.

In step S526, controller 30A outputs a control command to both oil cooler fans to stop them and sets flag F2 to "0."

When the processing of step S526 is completed, the controller 30A ends the processing of this flowchart.

Meanwhile, in step S528, controller 30A outputs a control command to the non-shared oil cooler fan to stop it, and sets flag F2 to "0". This allows controller 30A to continue operating the shared oil cooler fan even when the degree of cooling required for oil cooler 70 is very low in a situation where the degree of heat exchange required for condenser 82B is relatively high. This makes it possible to prevent a situation in which the degree of heat exchange required for condenser 82B is insufficient, resulting in a decrease in the cooling or heating performance of air conditioner 80.

When the processing of step S528 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S530, the controller 30A determines whether the flag F3 is "1", that is, whether the operating condition of the common oil cooler fan related to the degree of heat exchange required for the condenser 82B is satisfied. If the flag F3 is not "1", the controller 30A proceeds to step S532, and if the flag F3 is "1", the controller 30A proceeds to step S534.

In step S532, controller 30A outputs a control command to the shared oil cooler fan to stop it and sets flag F2 to "0."

When the processing of step S532 is completed, the controller 30A ends the processing of this flowchart.

On the other hand, in step S534, controller 30A only performs the process of setting flag F3 to "1". This allows controller 30A to continue operating the shared oil cooler fan even when the degree of cooling required for oil cooler 70 is relatively low in a situation where the degree of heat exchange required for condenser 82B is relatively high. This makes it possible to prevent a situation in which the degree of heat exchange required for condenser 82B is insufficient, resulting in a decrease in the cooling performance or heating performance of air conditioner 80.

When the processing of step S534 is completed, the controller 30A ends the processing of this flowchart.

Thus, in this example, the multiple oil cooler fans include a shared oil cooler fan (an example of a shared fan) that is shared as part of the multiple condenser fans. Then, when the degree of heat exchange required for the oil cooler 70 (an example of a first device) is relatively low, the controller 30A preferentially operates the non-shared oil cooler fans other than the shared oil cooler fan among the multiple oil cooler fans. On the other hand, when the degree of heat exchange required for the oil cooler 70 is relatively high, the controller 30A operates the shared oil cooler fan in addition to the non-shared oil cooler fan.

This allows the controller 30A to suppress the impact on the degree of heat exchange of the condenser 82B that may occur when operating the oil cooler fan, based on the degree of cooling required for the oil cooler 70.

In addition, in this example, even if the condition for stopping the shared oil cooler fan based on the degree of heat exchange (cooling degree) required for the oil cooler 70 is met while the shared oil cooler fan is operating, if the condition for stopping the shared oil cooler fan based on the degree of heat exchange required for the condenser 82B is not met, the controller 30A continues operating the shared oil cooler fan.

This allows the controller 30A to prevent a situation in which the degree of heat exchange in the condenser 82B becomes insufficient, thereby affecting the air conditioning performance of the air conditioner 80.

The oil cooler 70, condenser 82B, and fan 90 may be arranged so that all of the multiple condenser fans are shared oil cooler fans. In this case, the controller 30A employs a similar control method to achieve the same actions and effects.

<Control process related to the capacitor of the control device>
Next, the control process for the condenser fan by the control device 30 will be described with reference to FIG.

Figure 18 is a flow chart that shows a schematic diagram of a second example of the control process for the condenser fan by the control device 30 (controller 30A). In the following, flag F3 indicates whether or not the operating conditions for the condenser fans (fan 90G, fan 90I) related to the degree of heat exchange required for the condenser 82B are met. The explanation will proceed under the assumption that flag F3 is initially set to "0" and is initialized to "0" when the excavator is started.

As shown in FIG. 18, in step S602, controller 30A determines whether flag F3 is "1", that is, whether the operating conditions for the condenser fan based on the degree of heat exchange required for condenser 82B are met. If flag F3 is not "1", controller 30A proceeds to step S604, and if flag F3 is "1", controller 30A proceeds to step S608.

Step S604 is the same process as step S304 in FIG. 11. If the determination condition is met, controller 30A proceeds to step S606, and if the determination condition is not met, controller 30A ends the processing of this flowchart.

In step S606, the controller 30A operates both condenser fans and sets flag F3 to "1". For example, when both condenser fans are stopped, the controller 30A outputs a control command to both condenser fans to start them, and sets flag F3 to "1". When both condenser fans are stopped, this corresponds to a case where both the operating conditions of the shared radiator fan based on the degree of cooling required for the radiator 62 and the operating conditions of the shared oil cooler based on the degree of cooling required for the oil cooler 70 are not satisfied (i.e., flags F1 and F2 are both "0"). Also, when only the shared radiator fan is operating, the controller 30A outputs a control command to the shared oil cooler fan to start them, and sets flag F3 to "1". When only the shared radiator fan is in operation, this corresponds to a case where the operating condition of the shared radiator fan based on the cooling degree required for the radiator 62 is satisfied (i.e., the flag F1 is "1"), and the operating condition of the shared oil cooler based on the cooling degree required for the oil cooler 70 is not satisfied (i.e., both flags F2 are "0"). In addition, when, for example, only the shared oil cooler fan is in operation, the controller 30A outputs a control command to the shared radiator fan to start operation, and sets the flag F3 to "1". When only the shared oil cooler fan is in operation, this corresponds to a case where the operating condition of the shared radiator fan based on the cooling degree required for the radiator 62 is not satisfied (i.e., the flag F1 is "0"), and the operating condition of the shared oil cooler based on the cooling degree required for the oil cooler 70 is satisfied (i.e., the flag F2 is "1"). In addition, when, for example, both condenser fans are already in operation, the controller 30A only performs the process of setting the flag F3 to "1". When both condenser fans are already operating, this corresponds to a case where both the operating conditions for the shared radiator fan, which is based on the degree of cooling required for the radiator 62, and the operating conditions for the shared oil cooler, which is based on the degree of cooling required for the oil cooler 70, are met (i.e., flags F1 and F2 are both "0").

When the processing of step S606 is completed, controller 30A ends the processing of this flowchart.

On the other hand, step S608 is the same process as step S308 in FIG. 11. If the determination condition is met, controller 30A proceeds to step S610, and if the determination condition is not met, controller 30A ends the processing of this flowchart.

In step S610, controller 30A determines whether flags F1 and F2 are both "0". That is, controller 30A determines whether both the operating conditions of the shared radiator fan based on the degree of cooling required for radiator 62 and the operating conditions of the shared oil cooler based on the degree of cooling required for oil cooler 70 are not satisfied. If flags F1 and F2 are both "0", controller 30A proceeds to step S612, and if at least one of flags F1 and F2 is not "0" (i.e., is "1"), controller 30A proceeds to step S614.

In step S612, controller 30A outputs a control command to both condenser fans to stop them and sets flag F3 to "0."

When the processing of step S612 is completed, controller 30A ends this flowchart.

On the other hand, in step S614, controller 30A determines whether flag F1 is "0." If flag F1 is "0," controller 30A proceeds to step S616, and if flag F1 is not "0" (i.e., is "1"), controller 30A proceeds to step S618.

In step S616, controller 30A outputs a control command to the shared radiator fan to stop it, and sets flag F3 to "0." This allows controller 30A to continue operating the shared oil cooler fan when the degree of cooling required for oil cooler 70 is very high, even if the degree of heat exchange required for condenser 82B is relatively low.

When the processing of step S616 is completed, controller 30A ends this flowchart.

On the other hand, in step S618, controller 30A determines whether flag F2 is "0." If flag F2 is "0," controller 30A proceeds to step S620, and if flag F2 is not "0" (i.e., flags F1 and F2 are both "1"), controller 30A proceeds to step S622.

In step S620, the controller 30A outputs a control command to the shared oil cooler fan to stop it and sets flag F3 to "0." This allows the controller 30A to continue operating the shared radiator fan when the degree of heat exchange required for the condenser 82B is relatively low, but the degree of cooling required for the radiator 62 is very high.

When the processing of step S620 is completed, controller 30A ends the processing of this flowchart.

On the other hand, in step S622, the controller 30A only performs the process of setting the flag F3 to "0". This allows the controller 30A to continue operating the shared radiator fan and the shared oil cooler fan when the degree of cooling required for the radiator 62 and the oil cooler 70 is very high, even if the degree of heat exchange required for the condenser 82B is relatively low.

When the processing of step S622 is completed, the controller 30A ends the processing of this flowchart.

Thus, in this example, even if the condition for stopping the shared radiator fan based on the degree of heat exchange required for the condenser 82B is met while the shared radiator fan is operating, if the condition for stopping the shared radiator fan based on the degree of heat exchange (cooling degree) required for the radiator 62 is not met, the controller 30A continues operating the shared radiator fan.

This allows the controller 30A to prevent situations in which the degree of cooling in the radiator 62 is insufficient, thereby affecting the cooling performance of the cooling circuit 60.

In addition, in this example, even if the condition for stopping the shared oil cooler fan based on the degree of heat exchange required for the condenser 82B is met while the shared oil cooler fan is operating, if the condition for stopping the shared oil cooler fan based on the degree of heat exchange (degree of cooling) required for the oil cooler 70 is not met, the controller 30A continues operating the shared oil cooler fan.

This allows the controller 30A to prevent situations where the degree of cooling in the oil cooler 70 is insufficient, affecting the cooling performance of the hydraulic oil.

[Third Example of Fan Control Method]
Next, a third example of the fan control method will be described.

In this example, the control device 30 (controller 30A) limits the operation of the fan 90 while it is running in accordance with the operator's intentions.

For example, when a specific input is made through the input device 52 while the fan 90 is operating, the controller 30A may temporarily stop the operating fan 90 (for example, for a predetermined period of time) regardless of other conditions.

In addition, when a specific input is made through the input device 52 while the fan 90 is operating, the controller 30A may temporarily limit the rotation speed of the operating fan 90 to a relatively low state, regardless of other conditions.

The controller 30A may also stop all of the multiple fans 90 capable of blowing air to one heat exchange device or set them to a low rotation speed, or may stop only some of them or set them to a low rotation speed.

Thus, in this example, when a specific input is received by the input device 52, the controller 30A stops some or all of the multiple fans or transitions them to a state in which their rotation speed is relatively low.

As a result, in a situation where, for example, the operating noise of the fan 90 is interfering with communication with surrounding workers, the operator can make a specified input through the input device 52 to reduce the operating noise and facilitate communication with surrounding workers.

[Transformations/Changes]
Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist described in the claims.

For example, in the above-described embodiment, the configuration of the heat exchanger and fan mounted on a shovel that is not equipped with an engine, and the control method of the fan are described, but similar configurations and control methods may be applied to a shovel that is equipped with an engine. Specifically, the configuration of the radiator of the cooling circuit that cools the engine and the fan that cools the radiator, and the control method of the fan may be similar to those of the above-described embodiment.

In addition, in the above-mentioned embodiment and modified example, the configuration of the heat exchanger and fan mounted on the excavator and the control method of the fan are described, but the same configuration and control method may be applied to other work machines equipped with a heat exchanger and fan. Other work machines include, for example, industrial vehicles, forklifts, cranes, bulldozers, etc.

1 Lower traveling body 1A, 1B Travel hydraulic motor (hydraulic actuator)
3 Upper rotating body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder (hydraulic actuator)
8 Arm cylinder (hydraulic actuator)
9 Bucket cylinder (hydraulic actuator)
12 Pump motor (motor)
14 Main pump (hydraulic pump)
Reference Signs List 15 Pilot pump 18 Inverter unit 18A Inverter 18B Inverter 19 Power storage device 26 Operation device 30 Control device 30A to 30C Controller 44 DC-DC converter 46 Battery 50 Output device 52 Input device 54 Temperature sensor 56 Oil temperature sensor 60 Cooling circuit 62 Radiator (predetermined device)
64 Water pump 70 Oil cooler (prescribed equipment)
80 Air conditioner 82 Heat pump cycle 82A Compressor 82B Condenser (other equipment)
82C Expansion valve 82D Evaporator 90, 90A to 90J Fan

Claims (10)

A plurality of fans are provided which can blow air to a predetermined device that exchanges heat with the outside air,
The plurality of fans include a first fan capable of blowing air only to the predetermined device among other devices that are different from the predetermined device and exchange heat with outside air, and a second fan capable of blowing air to the predetermined device to which the first fan can blow air and the other devices,
Shovel. When a degree of heat exchange required for the specified device is relatively low, the first fan of the plurality of fans is preferentially operated, and when a degree of heat exchange required for the specified device is relatively high, the second fan is operated in addition to the first fan of the plurality of fans.
The shovel according to claim 1. Even if a condition for stopping the second fan based on the degree of heat exchange required for the specified device is satisfied while the second fan is in operation, if a condition for stopping the second fan based on the degree of heat exchange required for the other device is not satisfied, the operation of the second fan is continued.
The shovel according to claim 2. Among the plurality of fans, there is a case where only the second fan of the first fan and the second fan is in a stopped state or in an operating state with a rotation speed lower than that of the first fan.
A shovel according to any one of claims 1 to 3. When a degree of heat exchange required for the specified device is relatively high, the plurality of fans are controlled so as to rotate at a relatively high speed, and when a degree of heat exchange required for the specified device is relatively low, the plurality of fans are controlled so that only the second fan among the plurality of fans is stopped or rotates at a lower speed than the first fan.
A shovel according to any one of claims 1 to 4. When the temperature of the cooled fluid flowing inside the specified device or the temperature of the cooled device cooled through the cooled fluid is relatively high, the plurality of fans are controlled to rotate at a relatively high speed, and when the temperature is relatively low, the plurality of fans are controlled so that only the second fan among the plurality of fans is stopped or rotates at a lower speed than the first fan.
The shovel according to claim 5. There are a plurality of the predetermined devices,
The plurality of fans are provided corresponding to the plurality of predetermined devices,
A shovel according to any one of claims 1 to 6. The plurality of predetermined devices include a radiator of a cooling circuit that cools devices of an electric drive system, and an oil cooler that cools hydraulic oil supplied to a hydraulic actuator.
The shovel according to claim 7. An input device for receiving input,
When a predetermined input is received by the input device, some or all of the plurality of fans are stopped or transitioned to a state in which their rotation speeds are relatively low.
A shovel according to any one of claims 1 to 8. A hydraulic actuator;
a hydraulic pump for supplying hydraulic oil to the hydraulic actuator;
An electric motor that drives the hydraulic pump;
a power storage device for supplying power to the electric motor;
a drive device that drives the electric motor using electric power from the power storage device,
the predetermined device cools a refrigerant in a cooling circuit that cools devices in an electric drive system including the electric motor, the power storage device, and the drive device by heat exchange with outside air;
A shovel according to any one of claims 1 to 9.

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