WORK MACHINE CONTROL SYSTEM, WORK MACHINE AND WORK MACHINE CONTROL METHOD

Abstract

A control system for a working machine includes a key switch that is operated to be in an operating state of a key-off state, a key-on state, and a key-start state, an electric fan that generates an airflow for cooling an object to be cooled that is part of a working machine, and a controller that maintains the electric fan in a predetermined state in the key-on state.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a work machine control system, a work machine, and a work machine control method. STATE OF THE ART

[0002] In a technical field related to a work machine, a construction machine equipped with an electric fan that blows air to cool a battery device is known, as disclosed in Patent Document 1. List of citationsPatent literature

[0003] Patent document 1: JP 2020-051065 A SUMMARY OF THE INVENTIONTechnical Problem

[0004] An inspector may inspect or service a working machine while the machine is in a key-on state. For example, if an electric fan suddenly starts running while the inspector is near the electric fan during inspection or service of the working machine, the feasibility of the inspection or service may be compromised.

[0005] An object of the disclosure is to suppress the deterioration of the feasibility of testing or maintaining a working machine. Solution to the problem

[0006] According to the disclosure, a control system for a work machine is provided, including a key switch configured to be in an operating state of a key-off state, a key-on state, and a key-start state when operated, an electric fan configured to generate an airflow for cooling an object to be cooled that is part of the work machine, and a controller configured to maintain the electric fan in a predetermined state in the key-on state. Advantageous effects of the invention

[0007] According to the disclosure, the deterioration of the feasibility of maintenance or inspection of a working machine is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram illustrating a work machine according to an embodiment. Fig. 2 is a block diagram illustrating the working machine according to the embodiment. Fig. 3 is a block diagram illustrating a control system of the work machine according to the embodiment. Fig. 4 is a block diagram illustrating a controller according to the embodiment. Fig. 5 is a flowchart illustrating a first example of a control method of the work machine according to the embodiment. Fig. 6 is a flowchart illustrating a second example of the control method of the work machine according to the embodiment. DESCRIPTION OF EMBODIMENTS

[0008] Embodiments of the disclosure are described below, but the disclosure is not limited to the embodiments. Components of the embodiments described below can be combined arbitrarily. Furthermore, in some cases, some components may not be used. work machine

[0009] Fig. 1 is a diagram illustrating a work machine 1 according to an embodiment. In the embodiment, the work machine 1 is an electric work machine that uses a battery 2 as a power source. The battery 2 is mounted on the work machine 1. In the embodiment, the work machine 1 is an electric shovel. The work machine 1 includes a lower traveling body 3 including a crawler belt, an upper swing body 4 supported by the lower traveling body 3, and a work implement 5 supported by the upper swing body 4. The work implement 5 includes a boom coupled to the upper swing body 4, an arm coupled to the boom, and a bucket coupled to the arm.

[0010] The battery 2 includes a secondary battery. At a worksite where the work machine 1 is working, 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 connected to and detached from the charging port 8. Power output from the charging device 6 is fed into the battery 2 via the cable 7 and the charging port 8. The battery 2 is charged by the power output from the charging device 6.

[0011] Fig. Figure 2 is a block diagram illustrating the work machine 1 according to the embodiment. The work machine 1 includes the battery 2, the 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.

[0012] The power distribution unit (PDU) 9 distributes power from the battery 2. The inverter 10 supplies the main motor 11 with power from the power distribution unit 9. The inverter 10 converts a DC voltage output by the power distribution unit 9 into an AC voltage and outputs the AC voltage to the main motor 11. The main motor 11 is an electric motor. The main motor 11 is driven by the power from the inverter 10. The hydraulic pump 12 is driven by the main motor 11. The hydraulic pump 12 discharges hydraulic oil. The hydraulic oil discharged from the hydraulic pump 12 is supplied to a hydraulic actuator of the work machine 1. The hydraulic drive of the work machine 1 includes a travel hydraulic motor that rotates the crawler belt of the lower traveling body 3, a swing hydraulic motor that swings the upper swing body 4, and a hydraulic cylinder that actuates the work tool 5.

[0013] The DC / DC converter 13 converts a voltage of the battery 2 output from the power distribution unit 9 into a predetermined voltage. In the embodiment, the DC / DC converter 13 reduces the voltage of the battery 2 at a predetermined step-down ratio. The electric fan 14 is driven based on a power output from the DC / DC converter 13. The electric fan 14 generates an airflow for cooling an object to be cooled, which is part 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 may be a water-cooled heat exchanger or an oil-cooled heat exchanger. The object to be cooled includes the liquid-cooled heat exchanger for cooling the battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13.The battery 2, the inverter 10, the main motor 11, and the DC / DC converter 13 can each be cooled by a water-cooled heat exchanger (chiller). The electric fan 14 generates an airflow to cool the liquid-cooled heat exchanger. The electric fan 14 includes a fan motor 14A and a fan 14B, which is rotated by the rotational force generated by the fan motor 14A. The fan motor 14A is an electric motor. Control system

[0014] Fig. 3 is a block diagram illustrating a 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, the electric fan 14, and a controller 30.

[0015] The key switch 21 is operated by an operator to be in an operating state of a key-off state, a key-on state, and a key-start state. When the operator turns the key while it is inserted into a key cylinder, the key switch 21 turns to one of the "off," "on," or "start" positions. When the key is turned to the "off" position, the key switch 21 is in the key-off state. When the key is turned to the "on" position, the key switch 21 is in the key-on state. When the key is turned to the "start" position, the key switch 21 is in the key-start state.

[0016] The key switch 21 outputs a key signal to the controller 30. The key signals output from the key switch 21 include 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.

[0017] When the key switch 21 is in the key-off state, neither the controller 30 nor the electric fan 14 are supplied with power. When the key switch 21 is in the key-off state, the main motor 11 cannot be operated. When the key switch 21 is in the key-on state, both the controller 30 and the electric fan 14 are supplied with power. 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, both the controller 30 and the electric fan 14 are supplied with power. 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 controls the main motor 11 by issuing a control command to the inverter 10.The control commands output to the inverter 10 include a voltage command and a current upper limit command to be input to the main motor 11. In the key-on state or key-start state, the controller 30 outputs a control command to the DC / DC converter 13 to drive the electric fan 14. The control commands output to the DC / DC converter 13 include a target speed command for the fan 14B, as well as a voltage command and a current upper limit command to be input to the fan motor 14A.

[0018] The temperature sensor 22 detects a temperature of the object to be cooled. As described above, components of the work 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 a temperature of the coolant in the liquid-cooled heat exchanger. Detection data of the temperature sensor 22 is transmitted from the temperature sensor 22 to the controller 30.

[0019] The controller 30 operates based on power supplied from the battery 2. The controller 30 maintains the electric fan 14 in a predetermined state in the key-on state. The predetermined state is a driven state or a stopped state. The driven state means that the fan 14B is in a rotating state. The rotating states of the fan 14B include a constant-speed rotating state in which the fan 14B rotates at a speed that is 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 rotating speed of the fan 14B in the constant-speed rotating state is preferably a low speed. The controller 30 may maintain the electric fan 14 in the driven state in the key-on state.The controller 30 can keep the electric fan 14 in the stopped state in the key-on state.

[0020] Fig. 4 is a block diagram illustrating the controller 30 according to the embodiment. The controller 30 includes a computer system 1000. The computer system 1000 includes a processor 1001 such as a central processing unit (CPU), a main memory 1002 including non-volatile memory such as read-only memory (ROM) and volatile memory such as random access memory (RAM), a memory 1003, and an interface 1004 including an input / output circuit. Functions of the controller 30 are stored as a computer program in the memory 1003. The processor 1001 reads the computer program from the memory 1003, loads the computer program into the main memory 1002, and executes the above-described processing according to the program. The computer program can be distributed to the computer system 1000 via a network.

[0021] As in Fig. 3, the controller 30 includes 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. Note that 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 may be configured as separate hardware (controller).

[0022] The key signal receiving unit 31 receives a key signal from the key switch 21. The key signals include a key off signal, a key on signal, and a key start signal. The detection data receiving unit 32 receives detection data from the temperature sensor 22. The detection data from the temperature sensor 22 indicates the temperature of the object to be cooled.

[0023] The determination unit 33 determines whether the key signal received by the key signal receiving unit 31 is the key-off signal, the key-on signal, or the key-start signal. The determination unit 33 determines whether the operating state of the key switch 21 is the key-off state, the key-on state, or the key-start state based on the key signal received by the key signal receiving unit 31.

[0024] The fan control unit 34 outputs a control command for controlling the electric fan 14 based on the operating state of the key switch 21 determined by the determination unit 33. In the embodiment, the fan control unit 34 controls the electric fan 14 by controlling the DC / DC converter 13. Controlling 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. Driving the electric fan 14 means driving the fan motor 14A. Stopping the electric fan 14 means stopping the fan motor 14A. Adjusting the rotation speed of the electric fan 14 includes adjusting the rotation speed of the fan motor 14A.

[0025] The storage unit 35 stores correlation data representing a relationship between the temperature of the object to be cooled and the rotational speed of the electric fan 14. The correlation data is predetermined. The correlation data is determined such that the lower the temperature of the object to be cooled, the lower the rotational speed of the electric fan 14, and the higher the temperature of the object to be cooled, the higher the rotational speed of the electric fan 14. First example of the control procedure

[0026] Fig. 5 is a flowchart illustrating a first example of a control method of the work machine 1 according to the embodiment. Fig. 5 illustrates an example in which the electric fan 14 is kept in the rotating state in the key-on state.

[0027] The key signal receiving unit 31 receives a key signal (step SA1). The determination unit 33 determines whether the operating 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). If it is determined in step SA2 that the operating 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.

[0028] When it is determined in step SA2 that the operating state of the key switch 21 is not the key-off state (step SA2: No), the determination unit 33 determines whether the operating state of the key switch 21 is the key-on state (step SA3).

[0029] If it is determined in step SA3 that the operating 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). The fan control unit 34 keeps the electric fan 14 in the driven state when the operating state of the key switch 21 is the key-on state. The fan control unit 34 continues to drive the electric fan 14 while the operating state of the key switch 21 is the key-on state. Setting the electric fan 14 to the driven state includes rotating the electric fan 14 at a low speed. The speed of the electric fan 14 may be a speed at which an inspector can recognize that the electric fan 14 is in the driven state. By rotating the electric fan 14 at a low speed, power consumption is reduced and noise generation is suppressed.

[0030] When the operating state of the key switch 21 is the key-on state, the fan control unit 34 can 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 control the electric fan 14 based on the detection data of the temperature sensor 22 and the correlation data stored in the storage unit 35 so that the lower the temperature of the object to be cooled, the lower the rotation speed of the electric fan 14, and the higher the temperature of the object to be cooled, the higher the rotation speed of the electric fan 14.

[0031] If it is determined in step SA3 that the operating state of the key switch 21 is not the key-on state (step SA3: No), the determination unit 33 determines that the operating state of the key switch 21 is the key-start state. If the operating state of the key switch 21 is the key-start state, the main motor 11 starts driving. If the operating 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 receiving unit 32 (step SA5). If the temperature of the object to be cooled detected by the temperature sensor 22 is lower than a predetermined temperature threshold, the fan control unit 34 rotates the electric fan 14 at a speed lower than a predetermined speed.If 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 speed higher than the predetermined speed. If 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 adjust the 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 control the electric fan 14 based on the detection data of the temperature sensor 22 and the correlation data stored in the storage unit 35 such that the lower the temperature of the object to be cooled, the lower the speed of the electric fan 14, and the higher the temperature of the object to be cooled, the higher the speed of the electric fan 14. Second example of the control procedure

[0032] Fig. 6 is a flowchart illustrating a second example of the control method of the work machine 1 according to the embodiment. Fig. 6 illustrates an example in which the electric fan 14 is kept in a stopped state in the key-on state.

[0033] The key signal receiving unit 31 receives a key signal (step SB1). The determination unit 33 determines whether the operating 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). If it is determined in step SB2 that the operating 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.

[0034] When it is determined in step SB2 that the operating state of the key switch 21 is not the key-off state (step SB2: No), the determination unit 33 determines whether the operating state of the key switch 21 is the key-on state (step SB3).

[0035] If it is determined in step SB3 that the operating 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). The fan control unit 34 keeps the electric fan 14 stopped when the operating state of the key switch 21 is the key-on state. The fan control unit 34 continues to stop the electric fan 14 while the operating state of the key switch 21 is the key-on state. The fan control unit 34 prohibits driving the electric fan 14 while the operating state of the key switch 21 is the key-on state.

[0036] If it is determined in step SB3 that the operating state of the key switch 21 is not the key-on state (step SB3: No), the determination unit 33 determines that the operating state of the key switch 21 is the key-start state. If the operating state of the key switch 21 is the key-start state, the main motor 11 starts driving. If the operating 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 receiving unit 32 (step SB5). If the temperature of the object to be cooled detected by the temperature sensor 22 is lower than a predetermined temperature threshold, the fan control unit 34 rotates the electric fan 14 at a speed lower than a predetermined speed.If 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 speed higher than the predetermined speed. If 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 adjust the 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 control the electric fan 14 based on the detection data of the temperature sensor 22 and the correlation data stored in the storage unit 35 such that the lower the temperature of the object to be cooled, the lower the speed of the electric fan 14, and the higher the temperature of the object 1 to be cooled, the higher the speed of the electric fan 14. Effects

[0037] As described above, the work machine 1 includes the key switch 21 that is operated to be in any one of the key-off state, the key-on state, and the key-start state, the electric fan 14 that generates an airflow for cooling the object to be cooled that is part of the work machine 1, and the controller 30 that keeps the electric fan 14 in the key-on state in a predetermined state.

[0038] According to the embodiment, the electric fan 14 is kept in the driven or stopped state when an inspector inspects or maintains the work machine 1 in the key-on state. The operation of the electric fan 14 is determined not based on the temperature of the object to be cooled, but based on the operating state of the key switch 21. Accordingly, the deterioration of the feasibility of inspection or maintenance is suppressed. If the electric fan 14 continues to operate while the work machine 1 is in the key-on state, an inspector can efficiently perform inspection or maintenance work while staying away from the electric fan 14.If the electric fan 14 continues to be stopped while the working machine 1 is in the key-on state, the electric fan 14 does not suddenly start driving when an inspector is near the electric fan 14, thereby allowing the inspector to efficiently perform the inspection or maintenance work.

[0039] When the electric fan 14 is kept in the rotating state while the work machine 1 is in the key-on state, the fan control unit 34 can adjust the rotational speed of the electric fan 14 as desired. For example, the generation of noise can be suppressed by rotating the electric fan 14 at a low speed when the work machine 1 is in the key-on state. In addition, by rotating the electric fan 14 at a low speed, the power consumption of the electric fan 14 can be reduced. Furthermore, as described with reference to Fig.5, by adjusting the rotational speed of the electric fan 14 based on the temperature of the object to be cooled when the working machine 1 is in the key-on state, the object to be cooled can be appropriately cooled even when the working machine 1 is in the key-on state.

[0040] When the electric fan 14 is kept stopped while the work machine 1 is in the key-on state, noise generation can be suppressed. Furthermore, when the work machine 1 is in the key-on state, the operation of the electric fan 14 is inhibited, allowing an inspector to efficiently perform inspection or maintenance work on the work machine 1. Other embodiments

[0041] In the above-described embodiment, the object to be cooled by the electric fan 14 is the coolant in 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 in the radiator. 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 can cool hydraulic oil of a hydraulic system of the work machine 1.

[0042] When there are multiple objects to be cooled, the controller 30 may drive the electric fan 14 at the maximum rotational speed of the electric fan 14, which is determined based on the respective temperatures of the multiple objects to be cooled. For example, when a radiator, an oil cooler, and an air conditioning condenser are mounted on the work machine 1 as objects to be cooled, correlation data representing relationships between the temperatures of the multiple objects to be cooled and the respective rotational speeds of the electric fan 14 may be stored in the storage unit 35. The correlation data may be determined such that the lower the temperature of the object to be cooled, the lower the rotational speed of the electric fan 14, and the higher the temperature of the object to be cooled, the higher the rotational speed of the electric fan 14.Based on the temperatures of the objects to be cooled and the correlation 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 condenser is determined as the third rotational speed, and when, for example, 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.

[0043] In the embodiment described above, the work machine 1 is an electric shovel excavator. The work machine 1 can be, for example, an electric forklift.

[0044] In the above-described embodiment, the drive source of the work machine 1 is the main engine 11. That is, the work machine 1 is an electric work machine. The drive source of the work machine 1 may be a motor. The object to be cooled by the electric fan 14 may be an engine or a radiator that cools the engine. List of reference symbols

[0045] 1 Working machine, 2 Battery, 3 Lower traveling body, 4 Upper slewing body, 5 Working tool, 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 Determination unit, 34 Fan control unit, 35 Storage unit, 1000 Computer system, 1001 Processor, 1002 Main memory, 1003 Storage, 1004 Interface. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-051065 A

[0003]

Claims

[1] Control system for a work machine, comprising: a key switch configured to be in an operating state of a key-off state, a key-on state, and a key-start state when operated; an electric fan configured to generate an airflow for cooling an object to be cooled that is part of a work machine; and a controller configured to maintain the electric fan in a predetermined state in the key-on state. [2] A control system for a work machine according to claim 1, wherein the controller keeps the electric fan in a driven state in the key-on state. [3] A control system for a work machine according to claim 2, comprising: a temperature sensor configured to detect a temperature of the object to be cooled, wherein the controller adjusts the speed of the electric fan based on the detection data of the temperature sensor in the key-on state. [4] A control system for a work machine according to claim 1, wherein the controller keeps the electric fan in a stopped state in the key-on state. [5] A control system for a work machine according to claim 2 or 4, comprising: a temperature sensor configured to detect a temperature of the object to be cooled, wherein In the key start state, when a temperature of the object to be cooled detected by the temperature sensor is lower than a temperature threshold, the controller stops the electric fan, and when the temperature of the object to be cooled is equal to or higher than the temperature threshold, the controller controls the electric fan. [6] A control system for a work machine according to claim 5, wherein the working machine includes an electric motor and a hydraulic pump driven by the electric motor and the object to be cooled includes the electric motor. [7] Work machine, comprising: the control system for a work machine according to claim 1. [8] Control method for a work machine, comprising: Detecting an operating state of a key switch, wherein the key switch is in an operating state of a key-off state, a key-on state, and a key-start state by actuation; and Maintaining, in the key-on state, an electric fan in a predetermined state, the electric fan generating an airflow for cooling an object to be cooled which is part of a working machine.

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