Work machine control system, work machine, and work machine control method

Abstract

This control system for a work machine is provided with: a key switch that is operated to be in any one of a key power-off state, a key power-on state, and a key-on state; an electric fan for generating an air flow for cooling a cooling target of the work machine; and a controller that maintains the electric fan in a preset state when the key is energized.

Description

Technical Field

[0001] The present invention relates to a control system for a work machine, a work machine, and a control method for a work machine. Background Art

[0002] In the technical field related to work machines, a construction machine disclosed in Patent Document 1 is known, which includes an electric fan for blowing external air to a battery device to cool it.

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-051065 Summary of the Invention

[0004] Sometimes, an inspector inspects or repairs a work machine when the work machine is in the key-on state. During the inspection or repair work of the work machine, for example, if the electric fan suddenly starts to operate when the inspector is near the electric fan, the work efficiency of the inspection or repair may be reduced.

[0005] An object of the present disclosure is to suppress a reduction in the work efficiency of the inspection or repair of a work machine.

[0006] According to the present disclosure, there is provided a control system for a work machine, including: a key switch that is operated to be in any one of a key-off state, a key-on state, and a key-start state; an electric fan that generates an air flow for cooling a cooling object of the work machine; and a controller that maintains the electric fan in a preset state in the key-on state.

[0007] According to the present disclosure, it is possible to suppress a reduction in the work efficiency of the repair or inspection of a work machine. Brief Description of the Drawings

[0008] Figure 1 is a diagram schematically showing a work machine according to an embodiment.

[0009] Figure 2 is a block diagram showing a work machine according to an embodiment.

[0010] Figure 3 is a block diagram showing a control system for a work machine according to an embodiment.

[0011] Figure 4 is a block diagram showing a controller according to an embodiment.

[0012] Figure 5 is a flowchart showing a first example of a control method for a work machine according to an embodiment.

[0013] Figure 6 is a flowchart showing a second example of a control method for a work machine according to an embodiment. Detailed Embodiments

[0014] Hereinafter, embodiments of the present disclosure will be described, but the present disclosure is not limited to the embodiments. The constituent elements of the embodiments described below can be appropriately combined. In addition, there are cases where some constituent elements are not used.

[0015] Work Machine

[0016] Figure 1 FIG. schematically shows the work machine 1 of the embodiment. In the embodiment, the work machine 1 is an electric work machine with the battery 2 as the drive source. The battery 2 is mounted on the work machine 1. In the embodiment, the work machine 1 is an electric excavator. The work machine 1 has: a lower traveling body 3 with crawlers, an upper revolving body 4 supported by the lower traveling body 3, and a working machine 5 supported by the upper revolving body 4. The working machine 5 includes: an arm connected to the upper revolving body 4, a boom connected to the arm, and a bucket connected to the boom.

[0017] The battery 2 includes a secondary battery. At the work site of the work machine 1, the battery 2 is charged by a charging device 6. In the embodiment, the battery 2 includes a rechargeable lithium-ion battery. The charging device 6 is connected to the work machine 1 via a cable 7. The work machine 1 is provided with a charging port 8. The cable 7 is detachable from the charging port 8. The electricity output from the charging device 6 is input to the battery 2 via the cable 7 and the charging port 8. The battery 2 is charged based on the electricity output from the charging device 6.

[0018] Figure 2 FIG. is a block diagram showing the work machine 1 of the embodiment. The work machine 1 has: a battery 2, a charging port 8, a power distribution unit 9, an inverter 10, a main motor 11, a hydraulic pump 12, a DC / DC converter 13, and an electric fan 14.

[0019] The power distribution unit 9 (PDU: Power Distribution Unit) is used to distribute the electricity from the battery 2. The inverter 10 supplies the electricity from the power distribution unit 9 to the main motor 11. The inverter 10 converts the DC voltage output from the power distribution unit 9 into an AC voltage and then outputs it to the main motor 11. The main motor 11 is an electric motor. The main motor 11 is driven based on the electricity from the inverter 10. The hydraulic pump 12 is driven by the main motor 11. The hydraulic pump 12 is used to discharge hydraulic oil. The hydraulic oil discharged from the hydraulic pump 12 is supplied to the hydraulic actuators of the work machine 1. The hydraulic actuators of the work machine 1 include: a traveling hydraulic motor that rotates the crawlers of the lower traveling body 3, a slewing hydraulic motor that slews the upper revolving body 4, and a hydraulic cylinder that actuates the working machine 5.

[0020] The DC / DC converter 13 is configured to convert the voltage of the battery 2 output from the power distribution unit 9 into a preset voltage. In an embodiment, the DC / DC converter 13 steps down the voltage of the battery 2 at a preset step-down ratio. The electric fan 14 is driven based on the electricity output from the DC / DC converter 13. The electric fan 14 generates an air flow for cooling the object to be cooled of the work machine 1. In the embodiment, the battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13 are each cooled by a liquid-cooled heat exchanger. The liquid-cooled heat exchanger can be a water-cooled heat exchanger or an oil-cooled heat exchanger. The object to be cooled includes the liquid-cooled heat exchangers for cooling the battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13 respectively. The battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13 can also be cooled by a water-cooled heat exchanger (radiator). The electric fan 14 generates an air flow for cooling the liquid-cooled heat exchanger. The electric fan 14 includes: a fan motor 14A, and a fan 14B that rotates by the rotational force generated by the fan motor 14A. The fan motor 14A is an electric motor.

[0021] Control system

[0022] Figure 3 It is a block diagram showing the control system 20 of the work machine 1 according to the embodiment. The control system 20 includes: a key switch 21, a temperature sensor 22, an electric fan 14, and a controller 30.

[0023] The key switch 21 is operated by the operator and assumes any one of the operating states of key-off state, key-on state, and key-start state. When the operator rotates the key while the key is inserted into the lock cylinder, the key switch 21 is rotated to any one of the positions of "key-off", "key-on", and "key-start". When the key is rotated to the "key-off" position, the key switch 21 becomes the key-off state. When the key is rotated to the "key-on" position, the key switch 21 becomes the key-on state. When the key is rotated to the "key-start" position, the key switch 21 becomes the key-start state.

[0024] The key switch 21 outputs a key signal to the controller 30. The key signal output from the key switch 21 includes: a key-off signal output in the key-off state, a key-on signal output in the key-on state, and a key-start signal output in the key-start state.

[0025] When the key switch 21 is in the key-off state, power supply is not provided to the controller 30 and the electric fan 14 respectively. When the key switch 21 is in the key-off state, the main motor 11 is not driven. When the key switch 21 is in the key-on state, power supply is provided to the controller 30 and the electric fan 14 respectively. When the key switch 21 is in the key-on state, the main motor 11 cannot start driving. When the key switch 21 is in the key-start state, power supply is provided to the controller 30 and the electric fan 14 respectively. When the key switch 21 is in the key-start state, the main motor 11 starts driving. In the key-start state, the controller 30 drives the main motor 11 by outputting a control command to the inverter 10. The control command output to the inverter 10 includes a voltage command input to the main motor 11 and a current upper limit value command. In the key-on state or the key-start state, the controller 30 drives the electric fan 14 by outputting a control command to the DC / DC converter 13. The control command output to the DC / DC converter 13 includes: a target rotation speed command for the fan 14B, a voltage command input to the fan motor 14A, and a current upper limit value command.

[0026] The temperature sensor 22 is used to detect the temperature of the object to be cooled. As described above, components of the working machine 1 such as the battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13 are cooled by the liquid-cooled heat exchanger. In the embodiment, the temperature sensor 22 detects the temperature of the coolant of the liquid-cooled converter. The detection data of the temperature sensor 22 is sent from the temperature sensor 22 to the controller 30.

[0027] The controller 30 operates based on the power supply of the battery 2. In the key-on state, the controller 30 maintains the electric fan 14 in a preset state. The preset state is a driving state or a stop state. The driving state means that the fan 14B is in a rotating state. The rotating state of the fan 14B includes: a constant-speed rotating state in which the fan 14B rotates at a speed not determined based on the temperature of the object to be cooled, and a variable-speed rotating state in which the fan 14B rotates at a speed determined based on the temperature of the object to be cooled. The rotation speed of the fan 14B in the constant-speed rotating state is preferably a low rotation speed. In the key-on state, the controller 30 can maintain the electric fan 14 in the driving state. In the key-on state, the controller 30 can maintain the electric fan 14 in the stop state.

[0028] Figure 4FIG. 0 is a block diagram of a controller 30 showing an embodiment. The controller 30 includes a computer system 1000. The computer system 1000 has: a processor 1001, such as a CPU (Central Processing Unit); a main memory 1002 that includes a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory); a memory 1003; and an interface 1004 that includes input / output circuits. The functions of the controller 30 are stored in the memory 1003 as a computer program. The processor 1001 reads the computer program from the memory 1003 and loads it into the main memory 1002, and executes the above-described processing in accordance with the program. In addition, the computer program can also be transmitted to the computer system 1000 via a network.

[0029] As Figure 3 shown, the controller 30 has: a key signal receiving unit 31, a detection data receiving unit 32, a determination unit 33, a fan control unit 34, and a storage unit 35. In addition, the key signal receiving unit 31, the detection data receiving unit 32, the determination unit 33, the fan control unit 34, and the storage unit 35 can also be constituted by different hardware (controllers).

[0030] The key signal receiving unit 31 receives a key signal from the key switch 21. The key signal includes a key power-off signal, a key power-on signal, and a key start signal. The detection data receiving unit 32 receives detection data from the temperature sensor 22. The detection data of the temperature sensor 22 represents the temperature of the object to be cooled.

[0031] The determination unit 33 determines which of the key power-off signal, the key power-on signal, and the key start signal the key signal received by the key signal receiving unit 31 is. The determination unit 33 determines which of the key power-off state, the key power-on state, and the key start state the operation state of the key switch 21 is based on the key signal received by the key signal receiving unit 31.

[0032] The fan control unit 34 outputs a control command for controlling the electric fan 14 based on the operation state of the key switch 21 determined by the determination unit 33. In the embodiment, the fan control unit 34 controls the DC / DC converter 13, thereby controlling the electric fan 14. The control of the electric fan 14 includes driving the electric fan 14, stopping the electric fan 14, and adjusting the rotation speed of the electric fan 14. The driving of the electric fan 14 refers to driving the fan motor 14A. The stopping of the electric fan 14 refers to stopping the fan motor 14A. The adjustment of the rotation speed of the electric fan 14 includes adjusting the rotation speed of the fan motor 14A.

[0033] The storage unit 35 stores correlation data representing the relationship between the temperature of the object to be cooled and the rotational speed of the electric fan 14. The correlation data is preset data. The correlation data is set such that the lower the temperature of the object to be cooled, the slower the rotational speed of the electric fan 14, and the higher the temperature of the object to be cooled, the faster the rotational speed of the electric fan 14.

[0034] The first example of the control method

[0035] Figure 5 is a flowchart showing the first example of the control method of the work machine 1 according to the embodiment. Figure 5 shows an example in which the electric fan 14 is maintained in a rotating state in the key-on state.

[0036] The key signal receiving unit 31 receives a key signal (step SA1). The determination unit 33 determines whether the operation state of the key switch 21 is the key-off state based on the key signal received by the key signal receiving unit 31 (step SA2). In step SA2, when it is determined that the operation state of the key switch 21 is the key-off state (step SA2: Yes), the electric fan 14 is not driven, and the process returns to step SA1.

[0037] In step SA2, when it is determined that the operation state of the key switch 21 is not the key-off state (step SA2: No), the determination unit 33 determines whether the operation state of the key switch 21 is the key-on state (step SA3).

[0038] In step SA3, when it is determined that the operation state of the key switch 21 is the key-on state (step SA3: Yes), the fan control unit 34 drives the electric fan 14 (step SA4). When the operation state of the key switch 21 is the key-on state, the fan control unit 34 maintains the electric fan 14 in the driven state. The fan control unit 34 continuously drives the electric fan 14 during the period when the operation state of the key switch 21 is in the key-on state. Making the electric fan 14 in the driven state includes making the electric fan 14 rotate at a low speed. The rotational speed of the electric fan 14 only needs to be a speed at which the tester can confirm that the electric fan 14 is in the driven state. Since the electric fan 14 rotates at a low speed, power consumption is suppressed, and the generation of noise is also suppressed.

[0039] When the operation state of the key switch 21 is the key-on state, the fan control unit 34 can also adjust the rotation speed of the electric fan 14 based on the detection data of the temperature sensor 22 received by the detection data receiving unit 32. For example, the fan control unit 34 can also control the electric fan 14 based on the detection data of the temperature sensor 22 and the relevant data stored in the storage unit 35, so that the lower the temperature of the object to be cooled, the slower the rotation speed of the electric fan 14, and the higher the temperature of the object to be cooled, the faster the rotation speed of the electric fan 14.

[0040] In step SA3, when it is determined that the operation state of the key switch 21 is not the key-on state (step SA3: No), the determination unit 33 determines that the operation state of the key switch 21 is the key-start state. When the operation state of the key switch 21 is the key-start state, the driving of the main motor 11 is started. When the operation state of the key switch 21 is the key-start state, the fan control unit 34 controls the electric fan 14 based on the detection data of the temperature sensor 22 received by the detection data receiving unit 32 (step SA5). When the temperature of the object to be cooled detected by the temperature sensor 22 is lower than a preset temperature threshold, the fan control unit 34 rotates the electric fan 14 at a rotation speed lower than the preset rotation speed. When the temperature of the object to be cooled detected by the temperature sensor 22 is equal to or higher than the temperature threshold, the fan control unit 34 rotates the electric fan 14 at a rotation speed higher than the preset rotation speed. When the temperature of the object to be cooled detected by the temperature sensor 22 is equal to or higher than the temperature threshold, the fan control unit 34 can also adjust the rotation speed of the electric fan 14 based on the detection data of the temperature sensor 22 received by the detection data receiving unit 32. For example, the fan control unit 34 can also control the electric fan 14 based on the detection data of the temperature sensor 22 and the relevant data stored in the storage unit 35, so that the lower the temperature of the object to be cooled, the slower the rotation speed of the electric fan 14, and the higher the temperature of the object to be cooled, the faster the rotation speed of the electric fan 14.

[0041] Second example of the control method

[0042] Figure 6 It is a flowchart showing a second example of the control method of the working machine 1 according to the embodiment. Figure 6 An example is shown in which the electric fan 14 is maintained in a stopped state in the key-on state.

[0043] The key signal receiving unit 31 receives a key signal (step SB1). The determination unit 33 determines whether the operation state of the key switch 21 is the key-off state based on the key signal received by the key signal receiving unit 31 (step SB2). In step SB2, when it is determined that the operation state of the key switch 21 is the key-off state (step SB2: Yes), the electric fan 14 is not driven, and the process returns to step SB1.

[0044] In step SB2, when it is determined that the operation state of the key switch 21 is not the key-off state (step SB2: No), the determination unit 33 determines whether the operation state of the key switch 21 is the key-on state (step SB3).

[0045] In step SB3, when it is determined that the operation state of the key switch 21 is the key-on state (step SB3: Yes), the fan control unit 34 does not drive the electric fan 14 (step SB4). When the operation state of the key switch 21 is the key-on state, the fan control unit 34 maintains the electric fan 14 in the stopped state. The fan control unit 34 keeps the electric fan 14 stopped during the period when the operation state of the key switch 21 is in the key-on state. The fan control unit 34 prohibits the driving of the electric fan 14 during the period when the operation state of the key switch 21 is in the key-on state.

[0046] In step SB3, when it is determined that the operation state of the key switch 21 is not the key-on state (step SB3: No), the determination unit 33 determines that the operation state of the key switch 21 is the key-start state. When the operation state of the key switch 21 is the key-start state, the driving of the main motor 11 is started. When the operation state of the key switch 21 is the key-start state, the fan control unit 34 controls the electric fan 14 based on the detection data of the temperature sensor 22 received by the detection data receiving unit 32 (step SB5). When the temperature of the cooling object detected by the temperature sensor 22 is lower than a preset temperature threshold, the fan control unit 34 rotates the electric fan 14 at a speed lower than a preset rotation speed. When the temperature of the cooling object detected by the temperature sensor 22 is equal to or higher than the temperature threshold, the fan control unit 34 rotates the electric fan 14 at a speed higher than the preset rotation speed. When the temperature of the cooling object detected by the temperature sensor 22 is equal to or higher than the temperature threshold, the fan control unit 34 may also adjust the rotation speed of the electric fan 14 based on the detection data of the temperature sensor 22 received by the detection data receiving unit 32. For example, the fan control unit 34 may also control the electric fan 14 based on the detection data of the temperature sensor 22 and the relevant data stored in the storage unit 35, so that the lower the temperature of the cooling object, the slower the rotation speed of the electric fan 14, and the higher the temperature of the cooling object 1, the faster the rotation speed of the electric fan 14.

[0047] Effect

[0048] As described above, the work machine 1 includes: a key switch 21 that is operated to be in any one of a key-off state, a key-on state, and a key-start state; an electric fan 14 that generates an air flow for cooling a cooling object of the work machine 1; and a controller 30 that maintains the electric fan 14 in a preset state in the key-on state.

[0049] According to an embodiment, when an inspector inspects or repairs the work machine 1 while the work machine 1 is in the key-on state, the electric fan 14 is maintained in a driving state or a stopped state. The operation of the electric fan 14 is determined based on the operation state of the key switch 21, regardless of the temperature of the object to be cooled. Thereby, a decrease in the work efficiency of inspection or repair is suppressed. When the electric fan 14 is continuously driven while the work machine 1 is in the key-on state, the inspector can efficiently perform the inspection or repair work without approaching the electric fan 14. When the electric fan 14 is maintained stopped while the work machine 1 is in the key-on state, since the electric fan 14 does not suddenly start driving when the inspector is located near the electric fan 14, the inspector can efficiently perform the inspection or repair work.

[0050] When the electric fan 14 is maintained in a rotating state while the work machine 1 is in the key-on state, the fan control unit 34 can arbitrarily set the rotation speed of the electric fan 14. By rotating the electric fan 14 at a low speed, for example, while the work machine 1 is in the key-on state, generation of noise can be suppressed. In addition, since the electric fan 14 rotates at a low speed, power consumption of the electric fan 14 is suppressed. Further, as described with reference to Figure 5 by adjusting the rotation speed of the electric fan 14 based on the temperature of the object to be cooled while the work machine 1 is in the key-on state, the object to be cooled can be appropriately cooled even while the work machine 1 is in the key-on state.

[0051] When the electric fan 14 is maintained in a stopped state while the work machine 1 is in the key-on state, generation of noise can be suppressed. In addition, since driving of the electric fan 14 is prohibited while the work machine 1 is in the key-on state, the inspector can efficiently perform the inspection or repair work of the work machine 1.

[0052] Other embodiments

[0053] In the above embodiment, the object to be cooled by the electric fan 14 is the coolant of the liquid-cooled heat exchanger. The liquid-cooled heat exchanger may be a water-cooled heat exchanger (radiator) or an oil-cooled heat exchanger (oil cooler). When the liquid-cooled heat exchanger is a radiator, the object to be cooled by the electric fan 14 is the cooling water of the radiator. In addition, the components of the work machine 1 cooled by the liquid-cooled heat exchanger are not limited to the battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13. When the liquid-cooled heat exchanger is an oil cooler, the oil cooler may also cool the hydraulic oil of the hydraulic system of the work machine 1.

[0054] When there are multiple objects to be cooled, the controller 30 can also drive the electric fan 14 at the maximum rotational speed of the electric fan 14, and this maximum value is determined based on the temperatures of the multiple objects to be cooled. For example, when a radiator, an oil cooler, and a capacitor of an air conditioner are mounted on the work machine 1 as the objects to be cooled, relevant data representing the relationship between the temperatures of the multiple objects to be cooled and the rotational speed of the electric fan 14 can also be stored in the storage unit 35. The relevant data can also be set such that the lower the temperature of the object to be cooled, the slower the rotational speed of the electric fan 14, and the higher the temperature of the object to be cooled, the faster the rotational speed of the electric fan 14. Based on the temperature of the object to be cooled and the relevant data, the rotational speed of the electric fan 14 for cooling the radiator is determined as the first rotational speed, the rotational speed of the electric fan 14 for cooling the oil cooler is determined as the second rotational speed, and the rotational speed of the electric fan 14 for cooling the capacitor is determined as the third rotational speed. For example, when the first rotational speed is higher than the second rotational speed and the third rotational speed, the controller 30 can drive the electric fan 14 at the first rotational speed.

[0055] In the above-described embodiment, the work machine 1 is an electric excavator. The work machine 1 can also be, for example, an electric forklift.

[0056] In the above-described embodiment, the drive source of the work machine 1 is the main motor 11. That is, the work machine 1 is an electric work machine. However, the drive source of the work machine 1 can also be an engine. The object to be cooled by the electric fan 14 can be the engine or a radiator for cooling the engine.

[0057] Symbol Explanation

[0058] 1... Work machine; 2... Battery; 3... Lower traveling body; 4... Upper slewing body; 5... Working machine; 6... Charging device; 7... Cable; 8... Charging port; 9... Power distribution unit; 10... Inverter; 11... Main motor; 12... Hydraulic pump; 13... DC / DC converter; 14... Electric fan; 14A... Fan motor; 14B... Fan; 20... Control system; 21... Key switch; 22... Temperature sensor; 30... Controller; 31... Key signal receiving unit; 32... Detection data receiving unit; 33... Judgment unit; 34... Fan control unit; 35... Storage unit; 1000... Computer system; 1001... Processor; 1002... Main memory; 1003... Memory; 1004... Interface.

Claims

1. A control system for a work machine, characterized in that, it comprises: a key switch that is operated to be in any one of a key-off state, a key-on state, and a key-start state; an electric fan that generates an air flow for cooling a cooling object of the work machine; and a controller that maintains the electric fan in a preset state in the key-on state.

2. The control system for a work machine according to claim 1, characterized in that, in the key-on state, the controller maintains the electric fan in a driving state.

3. The control system for a work machine according to claim 2, characterized in that, it comprises: a temperature sensor that is used to detect the temperature of the cooling object, in the key-on state, the controller adjusts the rotation speed of the electric fan based on the detection data of the temperature sensor.

4. The control system for a work machine according to claim 1, characterized in that, in the key-on state, the controller maintains the electric fan in a stopped state.

5. The control system for a work machine according to claim 2 or 4, characterized in that, it comprises: a temperature sensor that is used to detect the temperature of the cooling object, in the key-start state, when the temperature of the cooling object detected by the temperature sensor is lower than a temperature threshold, the controller stops the electric fan, and when the temperature of the cooling object is equal to or higher than the temperature threshold, the controller drives the electric fan.

6. The control system for a work machine according to claim 5, characterized in that, the work machine has: an electric motor and a hydraulic pump driven by the electric motor, the cooling object includes the electric motor.

7. A work machine, characterized in that, it comprises the control system for a work machine according to claim 1.

8. A control method for a work machine, characterized in that, it includes: acquiring an operation state of a key switch that is operated to be in any one of a key-off state, a key-on state, and a key-start state; in the key-on state, maintaining an electric fan in a preset state, the electric fan generating an air flow for cooling a cooling object of the work machine.

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