JP7585108B2 - Fault diagnosis system and method for working machine - Google Patents

Description

This disclosure relates to a fault diagnosis system and a fault diagnosis method for a work machine.

JP 2016-151086 A (Patent Document 1) discloses an excavator support device in which time series data indicating the operating state of a dive to be diagnosed and typical time series data acquired from a database are compared and displayed on a display device. The above document describes that by comparing the time series data of the dive to be diagnosed with the typical time series data, if an abnormality occurs in the dive to be diagnosed, the abnormality can be intuitively confirmed.

JP 2016-151086 A

Even if a single time series of data is acquired and analyzed, it may be difficult to identify the true cause of the failure.

This disclosure proposes a fault diagnosis system and method for a work machine that can easily identify component failures.

According to an aspect of the present disclosure, a fault diagnosis system for a work machine is proposed. The fault diagnosis system includes a component mounted on the work machine, a detection unit that detects a predetermined physical quantity to monitor the operating status of the component, a controller, and a storage unit. The controller acquires time series data of the physical quantity detected during a predetermined period as snapshot data. The controller determines whether the physical quantity detected by the detection unit is within a normal range. The storage unit stores information that associates deviations of the physical quantity from the normal range with faults of the component that are the cause of the deviations. The controller acquires time series data detected during a first period as first snapshot data. The controller acquires time series data detected during a second period after the first period as second snapshot data. The controller identifies faults of the component based on the first snapshot data, the second snapshot data, and the information stored in the storage unit.

According to an aspect of the present disclosure, a fault diagnosis method for a work machine is proposed. The work machine includes a component and a detection unit that detects a predetermined physical quantity to monitor the operating status of the component. Information correlating deviations of the physical quantities detected by the detection unit from a normal range with faults of the components that are the cause of the deviations is stored in a storage unit. The fault diagnosis method includes the following steps. The first step is to acquire time series data of the physical quantities detected in a first period as first snapshot data. The second step is to acquire time series data of the physical quantities detected in a second period that is later than the first period as second snapshot data. The third step is to identify a fault in the component based on the first snapshot data, the second snapshot data, and the information stored in the storage unit.

The fault diagnosis system and fault diagnosis method disclosed herein make it possible to easily identify faults in components installed in a work machine.

1 is a diagram illustrating a schematic configuration of a work machine according to an embodiment of the present disclosure. FIG. 2 is a system diagram of the engine cooling system. FIG. 1 is a block diagram showing a configuration of a system based on an embodiment. FIG. 2 is a schematic diagram showing a first example of a failure cause database; FIG. 13 is a schematic diagram showing a second example of the failure cause database; FIG. 11 is a diagram showing snapshot data when each physical quantity is within a normal range. FIG. 11 is a diagram showing a first example of snapshot data when a physical quantity deviates from a normal range. FIG. 11 is a diagram showing a second example of snapshot data when a physical quantity deviates from a normal range. FIG. 13 is a diagram showing a third example of snapshot data when a physical quantity deviates from a normal range. FIG. 13 is a diagram showing a fourth example of snapshot data when a physical quantity deviates from a normal range. FIG. 13 is a diagram of a fifth example of snapshot data when a physical quantity deviates from a normal range. FIG. 1 is a flow diagram illustrating a process for identifying a component failure based on an embodiment. FIG. 11 is a diagram showing snapshot data at a point in time after a failure has occurred. FIG. 11 is a block diagram showing a system configuration based on a second embodiment. FIG. 13 is a block diagram showing a system configuration based on a third embodiment.

The following describes the embodiment with reference to the drawings. In the following description, identical parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[First embodiment]
<Overall configuration of the work machine>
Fig. 1 is a side view showing a schematic configuration of a hydraulic excavator 1 as an example of a work machine based on an embodiment of the present disclosure. As shown in Fig. 1, the hydraulic excavator 1 mainly includes a traveling body 2, a rotating body 3, and a work implement 4. The traveling body 2 and the rotating body 3 form the body of the hydraulic excavator 1.

The running body 2 has a pair of left and right tracks. The pair of left and right tracks are driven to rotate, causing the hydraulic excavator 1 to self-propel.

The rotating body 3 is installed so as to be freely rotatable with respect to the traveling body 2. The rotating body 3 mainly has a cab 7, an engine room 5, and a counterweight 6. The cab 7 is disposed, for example, at the front left side of the rotating body 3. An operator who operates the hydraulic excavator 1 boards the cab 7. A driver's seat for the operator is disposed inside the cab 7. The engine room 5 is disposed on the rear side of the rotating body 3 relative to the cab 7. The engine room 5 houses an engine unit (such as an engine 10 and an exhaust treatment structure described below). The counterweight 6 is disposed behind the engine room 5.

The working machine 4 is attached to the front side of the rotating body 3. The working machine 4 is disposed, for example, on the right side of the cab 7. The working machine 4 can be driven by a hydraulic cylinder. This drive allows the working machine 4 to rotate up and down relative to the rotating body 3.

<Cooling system configuration>
Fig. 2 is a system diagram of a cooling system for the engine 10. The engine 10 is mounted on the rotating body 3 shown in Fig. 1. The engine 10 is housed in the engine room 5. The cooling system for the engine 10 includes a cooling water circulation path 20 through which cooling water circulates. A cooling water pump 22, a water jacket 21A, a thermostat 24, and a radiator 26 are connected in this order via a cooling water pipe 21. The cooling water pressurized by the cooling water pump 22 flows through the water jacket 21A, the thermostat 24, and the radiator 26 in this order. The arrows along the cooling water circulation path 20 in Fig. 2 indicate the flow direction of the cooling water.

The cooling water pump 22 is driven by the driving force generated by the engine 10 to pump the cooling water. The water jacket 21A is a cooling water flow path provided inside the engine 10, for example, inside the cylinder block and cylinder head. Heat generated inside the engine 10 is transferred to the cooling water flowing through the water jacket 21A, thereby cooling the engine 10. The cooling water that has received heat from the engine 10 is cooled by heat exchange with the air in the radiator 26. The cooling water cooled in the radiator 26 returns to the cooling water pump 22.

The thermostat 24 controls the temperature of the coolant in the engine 10. When the temperature of the coolant in the engine 10 is low, the thermostat 24 is closed and the coolant does not flow to the radiator 26. A flow path for the coolant that circulates only within the engine 10 is formed, promoting an increase in the temperature of the engine 10. When the temperature of the coolant in the engine 10 becomes high, the thermostat 24 is opened and the coolant flows to the radiator 26. The coolant cooled by the radiator 26 circulates to the engine 10, and the engine 10 is cooled by heat dissipation to the coolant.

A reservoir tank 28 is connected to the radiator 26. A portion of the cooling water is stored in the reservoir tank 28. By allowing the cooling water to flow appropriately from the radiator 26 to the reservoir tank 28, or in the opposite direction, an appropriate amount of cooling water can circulate through the cooling water circuit 20.

Figure 2 also shows a hydraulic oil circulation path 30 through which hydraulic oil circulates. In this example, hydraulic oil refers to oil supplied to the hydraulic actuators 40 in order to operate the hydraulic actuators 40. The hydraulic actuators 40 include, for example, a hydraulic cylinder for driving the work machine 4, a rotation motor for rotating the rotating body 3 relative to the traveling body 2, and a traveling motor for traveling the traveling body 2.

The hydraulic oil pump 32, main valve 34, oil cooler 36, and hydraulic oil tank 38 are connected in this order via hydraulic oil piping 31. The hydraulic oil pressurized by the hydraulic oil pump 32 flows through the main valve 34, oil cooler 36, and hydraulic oil tank 38 in that order. The arrows along the hydraulic oil circulation path 30 in Figure 2 indicate the flow direction of the hydraulic oil.

Hydraulic oil is stored in the hydraulic oil tank 38. The hydraulic oil pump 32 is connected to the output shaft 12 of the engine 10 and receives the driving force generated by the engine 10 via the output shaft 12. The hydraulic oil pump 32 is driven by the driving force of the engine 10 and pumps the hydraulic oil in the hydraulic oil tank 38 to the main valve 34.

The main valve 34 has a built-in spool (not shown). The main valve 34 controls the flow rate and direction of hydraulic oil supplied to each hydraulic actuator 40 by the axial movement of the spool. The hydraulic oil that returns from the hydraulic actuator 40 to the main valve 34 is cooled by heat exchange with the air in the oil cooler 36. The hydraulic oil cooled in the oil cooler 36 returns to the hydraulic oil tank 38.

A bypass valve 37 is provided in the hydraulic oil piping 31 between the main valve 34 and the oil cooler 36. The bypass valve 37 supplies some of the hydraulic oil to the oil cooler 36 to cool it, and returns the remaining hydraulic oil directly to the hydraulic oil tank 38 without supplying it to the oil cooler 36. If the temperature of the hydraulic oil is low, the resistance to the hydraulic oil flow increases, resulting in reduced fuel efficiency. The amount of hydraulic oil cooled by the oil cooler 36 is adjusted by the bypass valve 37, thereby appropriately controlling the temperature of the hydraulic oil.

A cooling fan 16 is connected to the output shaft 11 of the engine 10. The cooling fan 16 is driven to rotate by the driving force of the engine 10 via the output shaft 11, thereby generating an air flow that passes through the radiator 26 and the oil cooler 36. The radiator 26 cools the coolant by dissipating heat into the air flow generated by the cooling fan 16. The oil cooler 36 cools the hydraulic oil by dissipating heat into the air flow generated by the cooling fan 16. The radiator 26 and the oil cooler 36 are disposed next to each other. The radiator 26 and the oil cooler 36 may be arranged in the direction of the air flow generated by the cooling fan 16.

A fan clutch 18 is provided on the output shaft 11 of the engine 10. The cooling fan 16 is connected to the engine 10 via the fan clutch 18. The fan clutch 18 can adjust the rotation speed of the cooling fan 16. When the rotation speed, cooling water temperature, and hydraulic oil temperature of the engine 10 are relatively low and there is little need to cool the cooling water and hydraulic oil, for example, immediately after starting the engine 10, the transmission of driving force from the engine 10 to the cooling fan 16 can be reduced, thereby reducing noise and loss for driving the cooling fan 16. When the rotation speed of the engine 10 increases and the cooling water temperature and hydraulic oil temperature increase, the fan clutch 18 becomes fully engaged and transmits driving force to the cooling fan 16 to increase the rotation speed of the cooling fan 16, thereby promoting cooling of the cooling water and hydraulic oil.

<Detection Unit 60>
2 is provided with a detection unit 60 that detects predetermined physical quantities. The detection unit 60 includes a water temperature sensor 61, an oil temperature sensor 62, a fan rotation speed sensor 63, a water level sensor 64, a fuel injection amount sensor 65, and an engine rotation speed sensor 66.

The water temperature sensor 61 detects the temperature of the cooling water. The temperature of the cooling water is used to monitor the operating conditions of the cooling fan 16, the cooling water pump 22, the thermostat 24, and the radiator 26. The oil temperature sensor 62 detects the temperature of the hydraulic oil. The temperature of the hydraulic oil is used to monitor the operating conditions of the cooling fan 16, the hydraulic oil pump 32, the oil cooler 36, and the bypass valve 37. The fan speed sensor 63 detects the rotation speed of the cooling fan 16. The rotation speed of the cooling fan 16 is used to monitor the operating conditions of the cooling fan 16. The rotation speed of the cooling fan 16 is also controlled by the controller 50 according to the temperatures detected by the water temperature sensor 61 and the oil temperature sensor 62.

The water level sensor 64 detects the level of the cooling water in the reservoir tank 28. The water level of the cooling water in the reservoir tank 28 is used to monitor the operating status of each device that constitutes the reservoir tank 28 and the cooling water circulation path 20. The fuel injection amount sensor 65 detects the amount of fuel supplied to the engine 10. The amount of fuel supplied to the engine 10 is used to monitor the operating status of the engine 10. The engine speed sensor 66 detects the rotation speed of the engine 10. The rotation speed of the engine 10 is used to monitor the operating status of the engine 10.

The detection unit 60 also includes an outside air temperature sensor 67. The outside air temperature sensor 67 detects the outside air temperature in the vicinity of the cooling system. The outside air temperature sensor 67 detects the temperature of the air supplied to the radiator 26 and the oil cooler 36.

The engine 10, cooling fan 16, cooling water circulation path 20, cooling water pump 22, thermostat 24, radiator 26, reservoir tank 28, hydraulic oil pump 32, oil cooler 36, and bypass valve 37 described above are included in the components mounted on a hydraulic excavator 1, which is an example of a work machine. The detector 60 detects a predetermined physical quantity to check the operating status of the component. Detection signals indicating the physical quantities detected by each detector 60 are input to the controller 50.

The water temperature sensor 61 shown in FIG. 2 is provided inside the engine 10, but the water temperature sensor 61 may be located at any position in the cooling water circuit 20. The oil temperature sensor 62 shown in FIG. 2 is provided in the hydraulic oil tank 38, but the oil temperature sensor 62 may be located at any position in the hydraulic oil circuit 30.

<Configuration of Controller 50>
3 is a block diagram showing the configuration of a system according to an embodiment. As shown in FIG. 3, the controller 50 includes an operation control unit 50A, a physical quantity acquisition unit 50B, a state determination unit 50C, a snapshot data acquisition unit 50D, a calculation processing unit 50E, and a storage unit 50F.

The operating device 52 shown in FIG. 3 accepts an operation by an operator to start the hydraulic excavator 1. The operating device 52 is disposed, for example, inside the cab 7. The operating device 52 is, for example, an engine key switch. The operation control unit 50A receives a detection signal from the operating device 52 indicating that the operating device 52 has been operated by the operator, and generates an instruction signal to operate the hydraulic excavator 1. The controller 50 outputs a control signal to each component, causing each component to operate. For example, the operation control unit 50A outputs an instruction signal to the engine 10, causing the engine 10 to start.

The physical quantity acquisition unit 50B receives, from each of the detection units 60 described with reference to FIG. 2, an input of a signal indicating the physical quantity detected by the detection unit 60.

The snapshot data acquisition unit 50D generates time series data for each physical quantity based on the physical quantities detected by the detection unit 60 and input to the physical quantity acquisition unit 50B. The snapshot data acquisition unit 50D acquires data that compiles the time series data for multiple physical quantities detected during a predetermined period as snapshot data. The acquired snapshot data is stored in the storage unit 50F, but is erased or updated with newly acquired snapshot data after a predetermined time has elapsed. Details of the snapshot data will be described later.

The state determination unit 50C determines whether each physical quantity detected by the detection unit 60 and input to the physical quantity acquisition unit 50B is within a normal range or deviates from the normal range. The state determination unit 50C may determine whether each physical quantity is within a normal range based on snapshot data.

The snapshot data acquisition unit 50D acquires, as first-appearance snapshot data, time-series data of physical quantities detected during a predetermined period going back from the time when the state determination unit 50C first determined that any physical quantity deviated from the normal range after the operation control unit 50A generated the instruction signal. The first-appearance snapshot data is stored in the storage unit 50F.

When the state determination unit 50C determines that any physical quantity deviates from the normal range, the calculation processing unit 50E identifies a component failure that is the cause of the deviation of the physical quantity from the normal range based on the snapshot data acquired by the snapshot data acquisition unit 50D. The memory unit 50F stores a failure cause database 50FDB. The failure cause database 50FDB contains information that associates the deviation of a physical quantity from the normal range with a component failure that is the cause of the deviation. The calculation processing unit 50E reads the failure cause database 50FDB from the memory unit 50F, and when a specific physical quantity deviates from the normal range, identifies one or more component failures that are the cause of the deviation.

The failure cause database 50FDB further includes information associating component failures with countermeasures for the failures. The calculation processing unit 50E outputs countermeasures for the component failures identified as the cause of the deviation of the physical quantity from the normal range. The calculation processing unit 50E displays the countermeasures for the component failures on the monitor 54, for example. The monitor 54 is disposed, for example, inside the cab 7. The monitor 54 is disposed, for example, in front of the driver's seat. The operator who operates the hydraulic excavator 1 from inside the cab 7 can recognize the component failure and the countermeasures for the failure by looking at the display on the monitor 54.

Each functional block of the controller 50 shown in FIG. 3 does not necessarily have to be realized by a single controller. The controller 50 shown in FIG. 3 may be realized by a combination of multiple controllers each including some of the functional blocks. For example, the physical quantity acquisition unit 50B and the calculation processing unit 50E may be configured as separate hardware.

<Fault Cause Database 50FDB>
Fig. 4 is a schematic diagram showing a first example of the failure cause database 50FDB. Fig. 4 shows a fault tree. In Fig. 4, the event targeted by the fault tree is overheating of the coolant of the engine 10. Overheating of the coolant of the engine 10 corresponds to an example of the deviation of a physical quantity from the normal range described above.

The occurrence of overheating of the engine 10 coolant is determined when the coolant temperature detected by the water temperature sensor 61 deviates from the normal range. The fact that the engine 10 speed detected by the engine speed sensor 66 deviates from the normal range and the output of the engine 10 is reduced may be used as an additional indicator of the occurrence of overheating.

Coolant overheating occurs due to insufficient heat dissipation from the coolant or excessive heat generation from the engine 10.

Insufficient heat dissipation from the coolant occurs due to an insufficient amount of coolant, poor circulation of the coolant, an insufficient amount of air blown onto the radiator 26 to dissipate heat from the coolant, or high temperature of the air blown onto the radiator 26 to dissipate heat from the coolant.

A cooling water shortage is detected when the cooling water level in the reservoir tank 28 detected by the water level sensor 64 deviates from the normal range.

The lack of coolant volume occurs due to coolant leakage or evaporation. Coolant leakage may occur in the coolant piping 21, the reservoir tank 28, or the radiator 26. Coolant evaporation may occur in the radiator 26. Therefore, in this case, the component in which the failure occurred is identified as either the coolant piping 21, the reservoir tank 28, or the radiator 26. The failure event of coolant leakage or evaporation in the coolant piping 21, the reservoir tank 28, or the radiator 26 and the visual inspection as a countermeasure against the failure are associated and stored in the memory unit 50F.

Poor cooling water circulation occurs due to a malfunction of the cooling water pump 22 or a malfunction of the thermostat 24.

A malfunction of the cooling water pump 22 occurs in the cooling water pump 22, and in this case, the component in which the malfunction occurred is identified as the cooling water pump 22. The malfunction of the cooling water pump 22, the replacement of the cooling water pump 22 as a countermeasure to the malfunction, and confirmation of the effect of the replacement are associated and stored in the memory unit 50F.

The thermostat 24 malfunction occurs in the thermostat 24, and in this case, the component in which the malfunction occurred is identified as the thermostat 24. The malfunction event of the thermostat 24 malfunctioning, the replacement of the thermostat 24 as a countermeasure to the malfunction, and confirmation of the effect after the replacement are associated and stored in the memory unit 50F.

Insufficient airflow to dissipate heat from the coolant occurs due to insufficient rotation speed of the cooling fan 16 or clogging of the heat dissipation surface of the radiator 26. Hereinafter, clogging of the radiator 26 refers to clogging of the heat dissipation surface of the radiator 26.

The occurrence of a lack of airflow due to the cooling fan 16 can be determined by the fact that the rotation speed of the cooling fan 16 detected by the fan rotation speed sensor 63 deviates from the normal range. The temperature of the hydraulic oil detected by the oil temperature sensor 62 deviates from the normal range, and the coolant and hydraulic oil overheat simultaneously occur, which can be used as an additional indicator of the occurrence of a lack of airflow.

The insufficient rotation speed of the cooling fan 16 occurs due to a malfunction of the cooling fan 16 or a malfunction of the fan clutch 18. In this case, the component in which the failure occurred is identified as the cooling fan 16 or the fan clutch 18. The failure event of the cooling fan 16 malfunctioning and the inspection, replacement, and confirmation of the effect after the replacement of the cooling fan 16 as countermeasures to the failure are associated and stored in the memory unit 50F. The failure event of the fan clutch 18 malfunctioning and the inspection, replacement, and confirmation of the effect after the repair of the fan clutch 18 as countermeasures to the failure are associated and stored in the memory unit 50F.

The clogging of the radiator 26 occurs in the radiator 26, and in this case, the component in which the failure occurred is identified as the radiator 26. The failure event of clogging of the radiator 26 and the visual inspection and cleaning of the radiator 26 as a countermeasure to the failure are associated and stored in the memory unit 50F.

The high temperature of the air blowing on the radiator 26 to dissipate heat from the coolant is related to high outside air temperature. A high outside air temperature is determined when the outside air temperature detected by the outside air temperature sensor 67 deviates from the normal range. The operator can confirm the cause of the problem of high outside air temperature by visually checking the outside air temperature displayed on the monitor 54.

Excessive heat generation from engine 10 occurs when the amount of fuel injected into engine 10 is excessive, or when the resistance or load generated by engine 10 is large.

The amount of fuel injected into the engine 10 is determined to be excessive when the amount of fuel supplied to the engine 10 detected by the fuel injection amount sensor 65 deviates from the normal range.

The excessive amount of fuel injected into the engine 10 occurs due to a malfunction of the injection pump 14 provided in the fuel supply system to the engine 10, and in this case, the component where the failure occurred is identified as the injection pump 14. The malfunction of the injection pump 14, and the inspection, replacement, and confirmation of the effect of the replacement of the injection pump 14 as measures against the malfunction are associated and stored in the memory unit 50F.

A large resistance generated in engine 10 means that a resistance or load is generated due to a defect, such as wear or breakage, occurring in a component of engine 10, such as a piston or piston ring. In this case, the component where the failure occurred is identified as the piston or piston ring. The failure event of a defective piston or piston ring and the inspection, replacement, and confirmation of the effect of the replacement as measures against the failure are associated and stored in memory unit 50F.

In this way, by analyzing the detection results of the detection unit 60 related to component failure, it is possible to easily identify the component failure that is causing the engine 10 coolant to overheat, and in addition, it is possible to easily understand countermeasures to the failure.

Figure 5 is a schematic diagram showing a second example of the fault cause database 50FDB. As in Figure 4, Figure 5 shows a fault tree. In Figure 5, the event that is the subject of the fault tree is overheating of hydraulic oil. Overheating of hydraulic oil corresponds to an example of the deviation of a physical quantity from the normal range described above. The occurrence of overheating of hydraulic oil is determined when the temperature of the hydraulic oil detected by the oil temperature sensor 62 deviates from the normal range.

Overheating of hydraulic oil occurs due to insufficient airflow directed at the oil cooler 36 to dissipate heat from the hydraulic oil, high temperature of the air directed at the oil cooler 36 to dissipate heat from the hydraulic oil, or poor circulation of the hydraulic oil.

Insufficient airflow to dissipate heat from the hydraulic oil occurs due to insufficient rotational speed of the cooling fan 16 or clogging of the heat dissipation surface of the oil cooler 36. Hereinafter, clogging of the oil cooler 36 refers to clogging of the heat dissipation surface of the oil cooler 36.

The occurrence of insufficient airflow due to the cooling fan 16 is determined when the rotation speed of the cooling fan 16 detected by the fan rotation speed sensor 63 deviates from the normal range. The insufficient rotation speed of the cooling fan 16 occurs due to a malfunction of the cooling fan 16 or a malfunction of the fan clutch 18. In this case, the component in which the failure occurred is identified as the cooling fan 16 or the fan clutch 18. The failure event of the cooling fan 16 malfunctioning and the inspection, replacement, and confirmation of the effect of the replacement as countermeasures to the failure are associated and stored in the memory unit 50F. The failure event of the fan clutch 18 malfunctioning and the inspection, replacement, and confirmation of the effect of the replacement as countermeasures to the failure are associated and stored in the memory unit 50F.

Clogging of the oil cooler 36 occurs in the oil cooler 36, and in this case, the component in which the failure occurred is identified as the oil cooler 36. The failure event of clogging of the oil cooler 36 and the visual inspection and cleaning of the oil cooler 36 as a countermeasure to the failure are associated and stored in the memory unit 50F.

The high temperature of the air blowing on the oil cooler 36 to dissipate heat from the hydraulic oil is related to high outside air temperature. A high outside air temperature is determined when the outside air temperature detected by the outside air temperature sensor 67 deviates from the normal range. The operator can confirm the cause of the malfunction, that is, high outside air temperature, by visually checking the outside air temperature displayed on the monitor 54.

Poor circulation of hydraulic oil occurs due to a malfunction of the hydraulic oil pump 32 or a malfunction of the bypass valve 37.

A malfunction of the hydraulic oil pump 32 occurs in the hydraulic oil pump 32, and in this case, the component in which the malfunction occurred is identified as the hydraulic oil pump 32. The malfunction event of the hydraulic oil pump 32 malfunctioning and the inspection, replacement, and confirmation of the effect of the replacement of the hydraulic oil pump 32 as measures against the malfunction are associated and stored in the memory unit 50F.

The failure of the bypass valve 37 occurs in the bypass valve 37, and in this case, the component in which the failure occurred is identified as the bypass valve 37. The failure event of the bypass valve 37 failing, the replacement of the bypass valve 37 as a countermeasure to the failure, and confirmation of the effect of the replacement are associated and stored in the memory unit 50F.

In this way, by analyzing the detection results of the detection unit 60 related to component failure, it is possible to easily identify the component failure that is causing the hydraulic oil to overheat, and in addition, it is possible to easily understand countermeasures to the failure.

<Snapshot data>
Next, a description will be given of data that is a compilation of time-series data of a plurality of physical quantities detected during a predetermined period, i.e., snapshot data. Fig. 6 is a diagram showing snapshot data when each physical quantity is within a normal range.

In FIG. 6 and the drawings showing snapshot data described below, a graph of time series data of cooling water temperature with time on the horizontal axis and temperature on the vertical axis, a graph of time series data of hydraulic oil temperature with time on the horizontal axis and temperature on the vertical axis, a graph of time series data of outside air temperature with time on the horizontal axis and temperature on the vertical axis, a graph of time series data of the rotation speed of the cooling fan 16 with time on the horizontal axis and rotation speed on the vertical axis, a graph of time series data of the rotation speed of the engine 10 with time on the horizontal axis and rotation speed on the vertical axis, a graph of time series data of the water level of the cooling water in the reservoir tank 28 with time on the horizontal axis and water level on the vertical axis, and a graph of time series data of the amount of fuel supplied to the engine 10 with time on the horizontal axis and fuel injection amount on the vertical axis are shown. These time series data shown in one figure, i.e., included in one snapshot data, show the time transition of each physical quantity during the same period.

Figure 6 shows snapshot data when each physical quantity is in a normal range. Specifically, the coolant temperature is maintained in a range higher than the threshold at which the thermostat 24 opens and lower than the threshold at which the coolant overheats for a specified period of time. The hydraulic oil temperature is maintained in a range lower than the threshold at which the hydraulic oil overheats, more specifically, lower than the threshold at which the cooling fan 16 rotates at its maximum speed, for a specified period of time. The outside air temperature is maintained in a range lower than the operating environment limit temperature, for example 45°C, for a specified period of time.

The rotation speed of the cooling fan 16 is maintained at approximately the maximum rotation speed for a specified period of time. The rotation speed of the engine 10 is maintained at approximately the rated rotation speed at which the driving force generated by the engine 10 is maximum for a specified period of time. The water level of the cooling water in the reservoir tank 28 is maintained at a water level lower than the threshold for the high water level and higher than the threshold for the low water level, more specifically, a water level slightly lower than the threshold for the high water level, for a specified period of time. The amount of fuel injected into the engine 10 is maintained at approximately the injection amount corresponding to the rated rotation speed at which the driving force generated by the engine 10 is maximum.

Figure 7 is a diagram of a first example of snapshot data when a physical quantity deviates from a normal range. Figure 7 shows snapshot data when the coolant temperature and hydraulic oil temperature deviate from their normal ranges. Specifically, the coolant temperature rises over time during a specified period and exceeds the threshold at which the coolant becomes overheated. The hydraulic oil temperature rises over time during a specified period and exceeds the threshold at which the rotation speed of the cooling fan 16 becomes maximum, reaching the threshold at which the hydraulic oil becomes overheated.

The outside air temperature rises gradually over a specified period of time. As the cooling water temperature and hydraulic oil temperature reach the thresholds at which overheating occurs, the temperature of the air passing through the radiator 26 and oil cooler 36 and being discharged rises, which is thought to be why the outside air temperature sensor 67 detects that the outside air temperature near the cooling system has risen.

The time progression of the engine 10 rotation speed, the time progression of the cooling water level in the reservoir tank 28, and the time progression of the amount of fuel injected into the engine 10 are the same as when they are in the normal range shown in Figure 6.

In the first example shown in FIG. 7, both the cooling water temperature and the hydraulic oil temperature have reached the threshold value at which overheating occurs. It is presumed that the common cause of the cooling water overheating shown in FIG. 4 and the hydraulic oil overheating shown in FIG. 5 is the cause of both the cooling water temperature and the hydraulic oil temperature becoming overheated. In other words, it is presumed that the cause of overheating is a lack of airflow to dissipate heat from the cooling water and hydraulic oil.

Therefore, by looking at the time progression of the rotation speed of the cooling fan 16, it is recognized that the rotation speed increases sharply at time T when the cooling water temperature reaches the threshold value that opens the thermostat 24, and is maintained at approximately the maximum rotation speed in the latter half of the specified period. Of the causes of the insufficient air volume shown in Figures 4 and 5, it is presumed that the insufficient rotation speed of the cooling fan 16 is not the cause. Therefore, if the radiator 26 and oil cooler 36 are clogged, a malfunction event is identified.

In this way, the calculation processing unit 50E (FIG. 3) identifies the component failure. The calculation processing unit 50E further outputs measures to address the component failure. In this case, the calculation processing unit 50E outputs a message to notify the operator to clean the radiator 26 and the oil cooler 36 to unclog them. For example, the calculation processing unit 50E displays a message on the monitor 54 urging the operator to clean the radiator 26 and the oil cooler 36 to unclog them.

Figure 8 is a diagram of a second example of snapshot data when a physical quantity deviates from a normal range. Figure 8 also shows snapshot data when the coolant temperature and hydraulic oil temperature deviate from their normal ranges. Specifically, the coolant temperature rises over time in a specified period and exceeds the threshold at which the coolant becomes overheated. The hydraulic oil temperature rises over time in a specified period and reaches the threshold at which the hydraulic oil becomes overheated.

The outside air temperature is balanced over a certain period of time, but is higher than when it is in the normal range shown in FIG. 6. The time progression of the engine 10 RPM, the time progression of the cooling water level in the reservoir tank 28, and the time progression of the amount of fuel injected into the engine 10 are the same as when they are in the normal range shown in FIG. 6.

In the second example shown in Figure 8, as in the first example shown in Figure 7, it is presumed that the cause of both the cooling water temperature and the hydraulic oil temperature overheating was a lack of airflow to dissipate heat from the cooling water and hydraulic oil.

Looking at the time progression of the rotation speed of the cooling fan 16, the rotation speed increases at time T when the cooling water temperature reaches the threshold value that opens the thermostat 24, but does not increase to the maximum rotation speed. Over the latter half of the specified period, the rotation speed of the cooling fan 16 is a value between the medium rotation speed and the maximum rotation speed. Of the causes of the insufficient air volume shown in Figures 4 and 5, it is presumed that the insufficient rotation speed of the cooling fan 16 is the cause. Therefore, if a malfunction of the cooling fan 16 or the fan clutch 18 occurs, a failure event is identified.

In this way, the calculation processing unit 50E identifies the component failure. The calculation processing unit 50E further outputs measures to address the component failure. In this case, the calculation processing unit 50E outputs information to notify the operator to inspect, replace, and confirm the effects of the replacement of the cooling fan 16 and the fan clutch 18. For example, the calculation processing unit 50E displays on the monitor 54 a message urging the operator to inspect, repair, and replace the cooling fan 16 and the fan clutch 18, and to confirm the effects thereafter.

Figure 9 is a diagram of a third example of snapshot data when a physical quantity deviates from a normal range. Figure 9 shows snapshot data when the coolant temperature deviates from the normal range, but the hydraulic oil temperature is in equilibrium. Specifically, the coolant temperature rises over time in a specified period and exceeds a threshold at which the coolant overheats. The hydraulic oil temperature is maintained in a range lower than the threshold at which the rotational speed of the cooling fan 16 is maximized in the specified period.

The outside air temperature is balanced over a specified period. The rotation speed of the cooling fan 16 increases sharply at time T when the coolant temperature reaches the threshold value that opens the thermostat 24, and is maintained at approximately maximum rotation speed in the latter half of the specified period. The time progression of the engine 10 rotation speed, the time progression of the coolant level in the reservoir tank 28, and the time progression of the amount of fuel injected into the engine 10 are the same as when they are in the normal range shown in Figure 6.

In the third example shown in FIG. 9, the cause of the rise in the cooling water temperature while the hydraulic oil temperature remains balanced is presumed to be a specific cause of cooling water overheating that is included in the causes of cooling water overheating shown in FIG. 4 but not included in the causes of hydraulic oil overheating shown in FIG. 5. In other words, it is presumed that a lack of air volume and high air temperature are not the causes of cooling water overheating. Since the water level of the cooling water in the reservoir tank 28 has not dropped, it is presumed that a lack of cooling water volume is not the cause. Since the fuel injection amount is balanced, it is presumed that an excessive fuel injection amount is not the cause. From these, if there is poor circulation of the cooling water, a malfunction event is identified.

In this way, the calculation processing unit 50E identifies the component failure. The calculation processing unit 50E further outputs measures to address the component failure. In this case, the calculation processing unit 50E outputs information to notify the operator of the replacement of the cooling water pump 22 and the thermostat 24 and confirmation of the effects of the replacement. For example, the calculation processing unit 50E displays information on the monitor 54 encouraging the operator to replace the cooling water pump 22 and the thermostat 24 and confirmation of the effects of the replacement.

Figure 10 is a diagram of a fourth example of snapshot data when a physical quantity deviates from a normal range. Figure 10 also shows snapshot data when the coolant temperature deviates from a normal range, but the hydraulic oil temperature is in equilibrium. Specifically, the coolant temperature rises over time in a specified period of time and exceeds a threshold at which the coolant overheats. The hydraulic oil temperature is maintained in a range lower than the threshold at which the rotational speed of the cooling fan 16 is maximized in the specified period of time.

The outside air temperature is balanced over a specified period. The rotation speed of the cooling fan 16 increases sharply at time T when the cooling water temperature reaches the threshold value that opens the thermostat 24, and is maintained at approximately maximum rotation speed in the latter half of the specified period. The time progression of the rotation speed of the engine 10 and the time progression of the amount of fuel injected into the engine 10 are the same as when they are in the normal range shown in Figure 6.

When looking at the change in the cooling water level in the reservoir tank 28 over time, the cooling water level decreases over a specified period of time and becomes even lower than the threshold value for the low water level.

In the fourth example shown in FIG. 10, the water level of the coolant in the reservoir tank 28 has dropped, so it is presumed that the cause of the overheating of the coolant is a lack of coolant. Therefore, if there is a coolant leak in the coolant pipe 21, the reservoir tank 28, or the radiator 26, or if the coolant has evaporated in the radiator 26, a fault event is identified.

In this way, the calculation processing unit 50E identifies the component failure. The calculation processing unit 50E further outputs measures to be taken against the component failure. In this case, the calculation processing unit 50E outputs a message to notify the operator to visually inspect the cooling water pipes 21, the reservoir tank 28, and the radiator 26. For example, the calculation processing unit 50E displays on the monitor 54 a message urging the operator to visually inspect the cooling water pipes 21, the reservoir tank 28, and the radiator 26.

Figure 11 is a diagram of a fifth example of snapshot data when a physical quantity deviates from a normal range. Figure 11 also shows snapshot data when the coolant temperature deviates from a normal range, but the hydraulic oil temperature is in equilibrium. Specifically, the coolant temperature rises over time in a specified period of time and exceeds a threshold at which the coolant overheats. The hydraulic oil temperature is maintained in a range below the threshold at which the rotational speed of the cooling fan 16 is maximized in the specified period of time.

The outside air temperature remains balanced for a specified period of time. The rotation speed of the cooling fan 16 increases sharply at time T when the coolant temperature reaches the threshold value that opens the thermostat 24, and is maintained at approximately maximum rotation speed in the latter half of the specified period. The time progression of the engine 10 rotation speed and the time progression of the coolant level in the reservoir tank 28 are the same as when they are in the normal range shown in Figure 6.

When looking at the time progression of the amount of fuel injected into the engine 10, the amount of fuel injected exceeds the rated amount of injection that maximizes the driving force generated by the engine 10. The actual amount of fuel injected is greater than the target value, which results in a decrease in fuel efficiency.

In the fifth example shown in FIG. 11, the amount of fuel injected into the engine 10 is greater than the amount of fuel injected corresponding to the rated rotation speed, so it is presumed that the excessive fuel injection amount is the cause of the overheating of the coolant. Therefore, if the injection pump 14 malfunctions, a failure event is identified.

In this way, the calculation processing unit 50E identifies the component failure. The calculation processing unit 50E further outputs measures to address the component failure. In this case, the calculation processing unit 50E outputs information to notify the operator to inspect, repair, and replace the injection pump 14, and to confirm the effects thereafter. For example, the calculation processing unit 50E displays a message on the monitor 54 encouraging the operator to inspect, repair, and replace the injection pump 14, and to visually check the effects after the replacement.

As described above, by the controller 50 (arithmetic processing unit 50E) analyzing the snapshot data, which is a sequence of time-series data for multiple physical quantities, it is possible to quickly identify which of the components of the hydraulic excavator 1 is in a faulty state.

The calculation processing unit 50E may identify a component failure based on the snapshot data using mathematical processing such as smoothing. Alternatively, the calculation processing unit 50E may have an artificial intelligence model for identifying a component failure from the snapshot data. This artificial intelligence model may be an artificial intelligence model that has been trained using learning data that includes a failure of a component and snapshot data acquired when the failure occurred.

The storage unit 50F (FIG. 3) may store in advance typical snapshot data when a failure occurs in a specific component as reference snapshot data. The storage unit 50F may store a plurality of reference snapshot data corresponding to various failures. The calculation processing unit 50E, which acquires snapshot data during the operation of the hydraulic excavator 1, can quickly identify the component failure by identifying reference snapshot data similar to the acquired snapshot data and reading out the failure corresponding to the identified reference snapshot data.

By storing information in memory unit 50F that associates the failure state of a component with measures to address the cause of that failure, when a component failure is identified, it becomes possible to read out that information from memory unit 50F. Based on that information, measures to address the failure can be implemented early, enabling a quicker recovery from the failure.

<Identifying component failures>
Next, a characteristic process for identifying a component failure based on an embodiment of the present disclosure will be described below. Fig. 12 is a flow diagram showing the flow of a process for identifying a component failure based on an embodiment.

As shown in FIG. 12, first, preparation is made to store reference snapshot data in advance in storage unit 50F (step S1). The reference snapshot data includes snapshot data when each physical quantity shown in FIG. 6 is within a normal range, and also includes typical snapshot data when a failure occurs in a specific component, as shown in FIG. 7 to FIG. 11.

The operator uses the operating device 52 (Figure 3) to perform an operation to start the hydraulic excavator 1. The controller 50 (operation control unit 50A) receives a detection signal from the operating device 52 indicating that the operating device 52 has been operated by the operator, and generates an instruction signal to operate the hydraulic excavator 1 (step S2).

The detection units 60 detect predetermined physical quantities to check the operating status of components mounted on the hydraulic excavator 1. The controller 50 (physical quantity acquisition unit 50B) acquires the physical quantities detected by the detection units 60 from each of the detection units 60 (step S3).

The controller 50 (state determination unit 50C) determines whether each physical quantity detected by the detection unit 60 and input to the physical quantity acquisition unit 50B is within a normal range, or whether the physical quantity is out of the normal range and the component in which the physical quantity was detected is in a faulty state (step S4). If it is determined that the component is not in a faulty state (NO in step S4), the subsequent process of identifying the fault is not executed, and the process returns to the process of acquiring the physical quantity in step S3.

If it is determined that any of the components is in a faulty state (YES in step S4), the controller 50 (snapshot data acquisition unit 50D) generates time series data of each physical quantity input to the physical quantity acquisition unit 50B, and acquires data that compiles the time series data of the multiple physical quantities detected during a predetermined period as snapshot data. The snapshot data acquired at this time is time series data of the physical quantities detected during a predetermined period going back from the time when it was first determined that the physical quantity deviated from the normal range, and is referred to as the first snapshot data (step S5). In this case, the first snapshot data is time series data of the physical quantities detected during the period from the time when it was first determined that the physical quantity deviated from the normal range going back a predetermined period of time from the time when it was first determined that the physical quantity deviated from the normal range to the time when it was first determined that the physical quantity deviated from the normal range.

Alternatively, the time series data of the physical quantity detected from the time when it is first determined that the physical quantity deviates from the normal range until a predetermined period of time has elapsed may be the first snapshot data. The time series data of the physical quantity detected during a predetermined period including the time when it is first determined that the physical quantity deviates from the normal range may be the first snapshot data. The first snapshot data corresponds to the first snapshot data in the embodiment. The period during which the time series data of the physical quantity included in the first snapshot data is detected corresponds to the first period in the embodiment.

The controller 50 stores the initial snapshot data acquired in step S5 in the memory unit 50F (step S6).

Data that compiles the time series data of the physical quantities for a period after the period when the initial snapshot data was acquired is acquired as in-operation snapshot data (step S7). For example, when an operator or repairman who knows that a component is in a faulty state inputs a signal to the controller 50 to command acquisition of snapshot data by operating the operation device 52, the controller 50 (snapshot data acquisition unit 50D) may acquire snapshot data for a predetermined period going back from the time when the input was received as in-operation snapshot data. In this case, the in-operation snapshot data is time series data of the physical quantities detected in the period from the time when the controller 50 received the input going back a predetermined period of time to the time when the controller 50 received the input.

Alternatively, the time series data of the physical quantities detected from the time when the controller 50 receives the input until a predetermined period of time has elapsed may be used as the operating snapshot data. The time series data of the physical quantities detected during a predetermined period including the time when the controller 50 receives the input may be used as the operating snapshot data. The operating snapshot data corresponds to the second snapshot data of the embodiment. The period during which the time series data of the physical quantities included in the operating snapshot data was detected corresponds to the second period of the embodiment.

Note that, if none of the physical quantities deviate from the normal range after step S6, and if the operator or repairman does not operate the operation device 52 or take any other action to input a signal to the controller 50 instructing it to acquire snapshot data, the process of step S7 may be skipped.

While the failure of the component determined to be in a failed state in step S4 is not resolved and the component continues to be in a failed state, the controller 50 may continuously or intermittently acquire snapshot data. The controller 50 may store the most recently acquired snapshot data in the storage unit 50F as running snapshot data and continue to update the running snapshot data. Upon receiving a command from an operator or repairman, the controller 50 may read and output the most recent running snapshot data stored in the storage unit 50F.

Based on the in-operation snapshot data, it is determined whether a component failure can be identified (step S8).

Figure 13 shows snapshot data at a point in time after the failure occurred. In Figure 13, the coolant temperature rises over time over a specified period of time and exceeds the threshold at which the coolant becomes overheated. The hydraulic oil temperature rises over time over a specified period of time and reaches the threshold at which the hydraulic oil becomes overheated.

The outside air temperature rises gradually over the course of the specified period. The rotation speed of the cooling fan 16 increases sharply at time T when the cooling water temperature reaches the threshold value that opens the thermostat 24, and is maintained at approximately maximum rotation speed in the latter half of the specified period. The time progression of the engine 10 rotation speed and the time progression of the amount of fuel injected into the engine 10 are similar to those when they are in the normal range shown in Figure 6. Looking at the time progression of the cooling water level in the reservoir tank 28, the cooling water level has been lower than the threshold value for the low water level over the specified period.

The in-operation snapshot data shown in FIG. 13 has a waveform that is different from the snapshot data of a typical fault occurrence contained in the reference snapshot data, making it difficult to identify a component fault based only on the in-operation snapshot data.

If it is determined that a component failure cannot be identified based on the operating snapshot data (NO in step S8), the process proceeds to step S9, where the controller 50 (arithmetic processing unit 50E) reads the first-time snapshot data from the memory unit 50F (step S9). The controller 50 (arithmetic processing unit 50E) identifies a component failure based on the first-time snapshot data (step S10).

For example, if the initial snapshot data stored in memory unit 50F is the same as the snapshot data shown in FIG. 9, then as explained with reference to FIG. 9, a fault event is identified as poor circulation of the coolant. In this case, at the time the fault occurred, the level of the coolant in reservoir tank 28 was slightly lower than the high water level threshold, meaning that there was a sufficient amount of coolant (FIG. 9). It is presumed that continued overheating of the coolant caused the coolant to evaporate, reducing the amount of coolant, which resulted in a drop in the level of the coolant in reservoir tank 28 (FIG. 13). It is presumed that a subsequent rise in outside air temperature led to overheating of the hydraulic oil.

For example, if the initial snapshot data stored in memory unit 50F is the same as the snapshot data shown in FIG. 10, as described with reference to FIG. 10, it is presumed that the cause of the overheating of the coolant is a shortage of the amount of coolant, and the fault event is identified as a coolant leak or evaporation. It is presumed that the subsequent rise in outside air temperature led to the overheating of the hydraulic oil.

If a component failure can be identified based on the in-operation snapshot data (YES in step S8), steps S9 and S10 are not performed.

Next, it is determined whether there are multiple countermeasures to the failure (step S11). For example, if the failure event is identified as poor cooling water circulation based on the snapshot data shown in FIG. 9, two causes of the failure are presumed to be a failure of the cooling water pump 22 and a failure of the thermostat 24. As countermeasures to the failure, it is presumed to replace the cooling water pump 22 and confirm the effect of the replacement, and to replace the thermostat 24 and confirm the effect of the replacement. In such a case, it is determined that there are multiple countermeasures to the failure.

When it is determined that there are multiple countermeasures for the failure (YES in step S11), the countermeasures are prioritized (step S12). For example, in the case of the above-mentioned poor circulation of the cooling water, the failure and repair history of the cooling water pump 22 and the failure and repair history of the thermostat 24 are stored in advance as maintenance history information in the memory unit 50F, and by reading the maintenance history information, it is possible to determine which component, the cooling water pump 22 or the thermostat 24, is more likely to have failed. As a result of this determination, a countermeasure for the failure corresponding to the component more likely to have failed is output (step S13). This output is performed, for example, by the controller 50 (arithmetic processing unit 50E) displaying the countermeasure for the component failure on the monitor 54.

If it is determined that there is only one solution to the fault (NO in step S11), the process in step S12 is not performed, and the solution to the identified fault is output in step S13. Then, the process ends (End in FIG. 12).

<Action and Effects>
Although some of the description herein overlaps with the above description, the characteristic configuration and effects of this embodiment can be summarized as follows.

In the fault diagnosis system according to the embodiment, as shown in FIG. 12, a component fault is identified based on the initial snapshot data and the in-operation snapshot data acquired after the initial snapshot data. When it is difficult to identify a component fault based only on the in-operation snapshot data at a time point after the occurrence of the fault, the component fault can be identified based on the initial snapshot data. In this way, a fault in a component mounted on the hydraulic excavator 1 can be easily identified. By accurately grasping the cause of the component fault and measures to address the cause of the fault and promptly implementing the measures, it becomes possible to quickly recover from the fault. Therefore, the downtime of the hydraulic excavator 1 can be shortened, and work efficiency can be improved.

As shown in FIG. 12, by using the earlier of two snapshot data that are chronologically separated as the first snapshot data immediately after a failure occurs, it is possible to identify a component failure with greater accuracy. By having the controller 50 generate an instruction signal for operating the hydraulic excavator 1, it is possible to reliably obtain the first snapshot data when a failure first occurs after the hydraulic excavator 1 is started.

As shown in FIG. 12, by storing the first appearance snapshot data in storage unit 50F, when it is difficult to identify a component failure based on the operating snapshot data alone, it becomes possible to read out the stored first appearance snapshot data and identify the component failure based on the first appearance snapshot data.

As shown in FIG. 12, measures to address the identified fault are output, allowing an operator or repairman to refer to the output and quickly implement measures to address the fault.

As shown in FIG. 12, when there are multiple countermeasures for a fault, the countermeasures are output with a priority, so that an operator or repairman can refer to the output and efficiently implement countermeasures for the fault.

[Second embodiment]
In the first embodiment, an example has been described in which the controller 50 mounted on the work machine identifies a component failure based on snapshot data. However, the present invention is not limited to this example, and a controller external to the work machine may identify a component failure. Figure 14 is a block diagram showing a system configuration based on a second embodiment.

As shown in FIG. 14, the hydraulic excavator 1 is equipped with the detection unit 60 described in the first embodiment. The controller 50 acquires the physical quantities detected by the detection unit 60. The hydraulic excavator 1 is equipped with a communication unit 56. The communication unit 56 has a communication function such as wireless communication.

A remote control device 70 is installed outside the hydraulic excavator 1. The remote control device 70 has an operating device (not shown) that is operated by an operator to operate the hydraulic excavator 1. Work is performed using the hydraulic excavator 1 by an operator operating the remote control device 70 in a remote location away from the work site where the hydraulic excavator 1 is working.

The communication unit 56 of the hydraulic excavator 1 transmits the physical quantities detected by the detection unit 60 to the remote control device 70. The controller 50 mounted on the hydraulic excavator 1 may generate time series data of the physical quantities, i.e., snapshot data, in which case the communication unit 56 transmits the snapshot data to the remote control device 70.

The remote control device 70 includes a fault diagnosis controller 71, a fault cause database 72, a monitor 74, and a communication unit 76. The communication unit 76 receives information transmitted by the communication unit 56 of the hydraulic excavator 1. The communication unit 76 inputs the received information on the physical quantities to the fault diagnosis controller 71.

Similar to the failure cause database 50FDB described in the first embodiment, the failure cause database 72 shown in FIG. 14 contains information that associates deviations of physical quantities from their normal ranges with failures of components that are the cause of the deviations.

The fault diagnosis controller 71 receives the input of the physical quantities received by the communication unit 76 and generates snapshot data of the physical quantities. When the snapshot data generated by the controller 50 of the hydraulic excavator 1 is transmitted to the communication unit 76, the fault diagnosis controller 71 receives the input of the snapshot data. The fault diagnosis controller 71 reads the fault cause database 72 and, similar to the first embodiment, identifies one or more faults in components that cause a deviation when a specific physical quantity deviates from the normal range based on the snapshot data and the fault cause database 72.

The fault diagnosis controller 71 transmits a signal to the monitor 74 to display the identified component fault and the countermeasures to be taken for that fault. The operator operating the remote control device 70 can recognize the component fault and the countermeasures to be taken for that fault by looking at the display on the monitor 74. Because the component fault and the countermeasures to be taken for that fault can be accurately identified from a remote location away from the work site where the hydraulic excavator 1 is operating, the countermeasures can be quickly implemented to enable a rapid recovery from the fault.

[Third embodiment]
Fig. 15 is a block diagram showing a system configuration according to the third embodiment. As in the first embodiment, the hydraulic excavator 1 according to the third embodiment is designed to be operated by an operator in a cab 7, and includes an operation device 52, a controller 50, and a detection unit 60. The controller 50 generates snapshot data and identifies a failure of a component based on the snapshot data. The hydraulic excavator 1 also includes a communication unit 56 described in the second embodiment.

The hydraulic excavator 1 is connected to a remote monitoring device 90 and a mobile terminal 100 via a network 80.

The remote monitoring device 90 is installed outside the hydraulic excavator 1 and monitors the operating status of the hydraulic excavator 1, the status of work performed by the hydraulic excavator 1, and the like from a remote location. The remote monitoring device 90 includes a server 91, a monitor 94, and a communication unit 96. An inspector or repairman of the hydraulic excavator 1 carries a mobile terminal 100. The mobile terminal 100 may be, for example, a smartphone, a tablet PC, or the like.

The communication unit 56 of the hydraulic excavator 1 transmits the identified component failure and countermeasures to the failure to the remote monitoring device 90 and the mobile terminal 100 via the network 80. The remote monitoring device 90 processes the component failure and countermeasures received by the communication unit 96 in the server 91 and displays them on the monitor 94. The mobile terminal 100 displays the received component failure and countermeasures on its screen.

An operator at a remote location who monitors the operating status of the hydraulic excavator 1 by referring to the remote monitoring device 90 can recognize component failures and countermeasures to address the failures by looking at the display on the monitor 74. Inspectors and repair personnel carrying the mobile terminal 100 can recognize component failures and countermeasures to address the failures by looking at the display on the screen of the mobile terminal 100. By accurately understanding the component failures and countermeasures to address the failures and quickly implementing the countermeasures, it becomes possible to quickly recover from the failure.

In the explanation of the embodiments so far, a hydraulic excavator 1 has been described as an example of a work machine, but the ideas of the present disclosure may also be applied to other types of work machines, such as bulldozers, wheel loaders, dump trucks, etc.

The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is indicated by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

1 hydraulic excavator, 2 travelling body, 3 swivel body, 4 work machine, 5 engine room, 7 cab, 10 engine, 11, 12 output shaft, 14 injection pump, 16 cooling fan, 18 fan clutch, 20 cooling water circulation path, 21 cooling water piping, 21A water jacket, 22 cooling water pump, 24 thermostat, 26 radiator, 28 reservoir tank, 30 hydraulic oil circulation path, 31 hydraulic oil piping, 32 hydraulic oil pump, 34 main valve, 36 oil cooler, 37 bypass valve, 38 hydraulic oil tank, 40 hydraulic actuator, 50 controller, 50A operation control unit, 50B physical quantity acquisition unit, 50C state determination unit, 50D snapshot data acquisition unit, 50E calculation processing unit, 50F storage unit, 50FDB, 72 failure cause database, 52 Operation device, 54, 74, 94 monitor, 56, 76, 96 communication unit, 60 detection unit, 61 water temperature sensor, 62 oil temperature sensor, 63 fan speed sensor, 64 water level sensor, 65 fuel injection amount sensor, 66 engine speed sensor, 67 outside air temperature sensor, 70 remote operation device, 71 fault diagnosis controller, 80 network, 90 remote monitoring device, 91 server, 100 mobile terminal.

Claims (6)

A component mounted on the work machine;
A detection unit that detects a predetermined physical quantity in order to monitor an operating condition of the component;
a controller that acquires time-series data of the physical quantity detected during a predetermined period as snapshot data and determines whether the physical quantity detected by the detector is within a normal range; and
a storage unit that stores information correlating a deviation of the physical quantity from a normal range with a failure of the component that is the cause of the deviation;
The controller:
The time series data detected during a first period is acquired as first snapshot data;
acquiring the time series data detected during a second period after the first period as second snapshot data;
determining whether a failure of the component can be identified based on the second snapshot data and the information stored in the storage unit;
a fault diagnosis system for a working machine that, when a fault of the component cannot be identified based on the second snapshot data, identifies a fault of the component based on the first snapshot data and information stored in the memory unit . The controller:
generating command signals for operating the work machine;
2. The fault diagnosis system for a work machine according to claim 1, wherein time series data of the physical quantity detected during the specified period going back from a point in time when it was first determined that the physical quantity deviated from a normal range after the instruction signal was generated is acquired as the first snapshot data. The fault diagnosis system for a work machine according to claim 1 or 2, wherein the controller stores the first snapshot data in the memory unit. the information stored in the storage unit includes information associating a failure of the component with a countermeasure for the failure,
4. The fault diagnosis system for a work machine according to claim 1, wherein the controller outputs a countermeasure against the identified fault based on the information stored in the memory unit. The fault diagnosis system for a work machine according to claim 4, wherein, when there are multiple countermeasures for a fault, the controller prioritizes the countermeasures and outputs them. 1. A fault diagnosis method for a working machine including a component and a detection unit that detects a predetermined physical quantity in order to monitor an operating condition of the component, comprising:
a storage unit stores information correlating a deviation of the physical quantity from a normal range detected by the detection unit with a failure of the component that is a cause of the deviation;
acquiring time series data of the physical quantity detected during a first period as first snapshot data;
acquiring, as second snapshot data, time series data of the physical quantity detected during a second period that is after the first period;
determining whether a failure of the component can be identified based on the second snapshot data and information stored in the storage unit;
and when a fault of the component cannot be identified based on the second snapshot data, identifying a fault of the component based on the first snapshot data and information stored in the storage unit .

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