Work machine and method for controlling work machine

Abstract

To control a work machine for further enhancing safety in the case where abnormality occurs in a power supply circuit outside a controller 10 in addition to the case where abnormality occurs inside the controller.SOLUTION: A work machine 1 having a work machine unit includes a power source 2 for outputting a drive force for operating the work machine unit, a controller 10, and an electromagnetic valve 6 controlled by the controller 10. When determining that abnormality has occurred in a power supply circuit for connecting the controller 10 and the electromagnetic valve 6, the controller 10 outputs a command for controlling the power source 2 so as to restrict the operation of the work machine unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a work machine and a control method for a work machine.

Background Art

[0002] As a functional safety measure for work machines such as hydraulic excavators, when an abnormality occurs inside the controller, the controller has a function of detecting the abnormality and cutting off the electric circuit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a work machine, in addition to the case where an abnormality occurs inside the controller, it is desirable to control the work machine so as to further enhance safety when an abnormality occurs in the power supply circuit outside the controller.

Means for Solving the Problems

[0005] According to the present disclosure, a work machine having a working device includes a power source that outputs a driving force for operating the working device, a controller, and a solenoid valve controlled by the controller. When the controller determines that an abnormality has occurred in the power supply circuit connecting the controller and the solenoid valve, the controller outputs a command to control the power source so as to limit the operation of the working device.

[0006] According to the present disclosure, a control method for a work machine having a working device, when it is determined that an abnormality has occurred in the power supply circuit connecting the controller for controlling the solenoid valve and the solenoid valve, a command is output to control the power source so as to limit the operation of the working device.

Effects of the Invention

[0007] According to the present disclosure, in addition to the case where an abnormality occurs inside the controller, when an abnormality occurs in the power supply circuit outside the controller, it is possible to control the working machine so as to further enhance safety, and a working machine and a control method for the working machine can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings, but the present disclosure is not limited thereto. The components of the embodiments described below can be combined as appropriate. Also, in some cases, some components may not be used.

[0010] (First Embodiment) [Working Machine] FIG. 1 is a schematic block diagram of a working machine 1 according to the first embodiment. In the present disclosure, the working machine 1 is a hydraulic excavator. The working machine 1 includes a lower traveling body (not shown), an upper revolving body (not shown), a working implement (not shown), and a hydraulic cylinder (not shown) for driving the working implement. The working machine 1 includes a power source 2, a solenoid valve 6, a battery 4 as a power source, and a controller 10. In the present disclosure, the working machine 1 includes a hydraulic actuator 3, an operation device 5, and a power source controller 30. In the present disclosure, as the solenoid valve 6, in addition to the solenoid valve 6c connected to the power source 2, as an example, there are two solenoid valves, i.e., a solenoid valve 6a and a solenoid valve 6b, but the present disclosure is not limited thereto.

[0011] In the present disclosure, the working machine 1 may include a notification unit (not shown) that notifies an abnormality in a power supply circuit external to the controller 10, in other words, a power supply circuit connecting the controller 10 and the solenoid valve 6. The notification unit is a notification device that notifies an operator in the driver's seat of the occurrence of an abnormality in the power supply circuit external to the controller 10. The notification unit is, for example, a monitor or a buzzer provided in the cab of the working machine 1.

[0012] The power source 2 outputs a driving force for operating the working implement. The power source 2 is controlled by a control signal from the power source controller 30. The power source 2 includes, for example, an engine, a generator, a fuel cell, a storage battery, an electric motor, and a variable displacement pump. In the present disclosure, the power source 2 will be described as having, as an example, an engine 2E and a variable displacement pump 2P.

[0013] A solenoid valve 6c is connected to the variable displacement pump 2P. The variable displacement pump 2P is, for example, a swash plate type hydraulic pump that changes the pump capacity by changing the tilt angle of the swash plate, but is not limited thereto. The variable displacement pump 2P is mechanically connected to the drive shaft 2X of the engine 2E. When the engine 2E is driven, the variable displacement pump 2P is driven. The variable displacement pump 2P serves as a supply source of hydraulic oil to the hydraulic actuator 3. In the present disclosure, the rotational speed of the engine 2E is controlled by a control signal from the power source controller 30. In the present disclosure, the tilt angle of the swash plate of the variable displacement pump 2P is controlled by a control signal from the controller 10.

[0014] The hydraulic actuator 3 is, for example, a hydraulic drive system such as a boom hydraulic cylinder, an arm hydraulic cylinder, a bucket hydraulic cylinder, a right traveling hydraulic motor, and a left traveling hydraulic motor. The hydraulic actuator 3 is driven by being supplied with hydraulic oil from the variable displacement pump 2P. When the hydraulic actuator 3 is driven, a working machine including a boom, a bucket, and an arm connected to the hydraulic actuator 3, a lower traveling body, and an upper revolving body operate. A control valve (not shown) for controlling the hydraulic actuator 3 is disposed between the hydraulic actuator 3 and the variable displacement pump 2P.

[0015] The battery 4 supplies power to the working machine 1. The battery 4 supplies power for driving the solenoid valve 6. In the present disclosure, the battery 4 supplies power for driving the solenoid valves 6a, 6b, and 6c. The battery 4 supplies power to the controller 10. An electric signal line 101 is electrically connected to the battery 4. The battery 4 is connected to the controller 10 via the electric signal line 101. The battery 4 is connected to the solenoid valve 6 via the electric signal line 101 and the controller 10. In the present disclosure, the battery 4 is connected to the solenoid valves 6a, 6b, and 6c via the electric signal line 101 and the controller 10. In the circuit for supplying power from the battery 4 to the controller 10, in other words, on the electric signal line 101, the battery 4 side is referred to as the upstream side.

[0016] The operating device 5 is arranged at the driver's seat of the working machine 1. The operating device 5 is operated by an operator. The operating device 5 is, for example, an operation lever for operating the boom, bucket, arm, and slewing of the upper slewing body. The operating device 5 is, for example, an operation lever for operating the travel hydraulic motor. The operating device 5 is, for example, a fuel dial. The operating device 5 is, for example, an operation switch for operating the slewing parking brake.

[0017] The operating device 5 outputs a signal indicating the operator's operation to the control unit 20. The operating device 5 outputs, for example, a boom operation signal indicating the operation direction and operation amount of the boom to the control unit 20. The operating device 5 outputs, for example, a bucket operation signal indicating the operation direction and operation amount of the bucket to the control unit 20. The operating device 5 outputs, for example, an arm operation signal indicating the operation direction and operation amount of the arm to the control unit 20. The operating device 5 outputs, for example, a slewing operation signal indicating the slewing direction and slewing amount of the upper slewing body with respect to the lower traveling body to the control unit 20. The operating device 5 outputs, for example, a travel operation signal for operating the travel motor to the control unit 20. The operating device 5 outputs, for example, a fuel dial signal indicating the throttle opening of the engine to the control unit 20. The operating device 5 outputs, for example, a slewing parking brake operation signal for operating the engagement or release of the slewing parking brake to the control unit 20.

[0018] The solenoid valve 6a performs an opening / closing operation, a direction switching operation, etc. by the electric power supplied from the battery 4. The upstream side of the solenoid valve 6a is connected to the downstream side of the switching element 14F. The downstream side of the solenoid valve 6a is connected to the ground 17G.

[0019] The solenoid valve 6b performs an opening / closing operation, a direction switching operation, etc. by the electric power supplied from the battery 4. The upstream side of the solenoid valve 6b is connected to the downstream side of the switching element 15F. The downstream side of the solenoid valve 6b is connected to the ground 18G.

[0020] The solenoid valves 6a and 6b are various solenoid valves provided in the working machine 1, such as those for switching the high and low traveling speeds of the working machine 1, those for switching the relief pressure of the attachment, and those for switching the engagement or release of the swing parking brake of the working machine 1.

[0021] The solenoid valve 6c performs opening and closing operations, direction switching operations, etc. by the electric power supplied from the battery 4. The upstream side of the solenoid valve 6c is connected to the downstream side of the switching element 13F. The downstream side of the solenoid valve 6c is connected to the ground 16G. The solenoid valve 6c is connected to the power source 2. The solenoid valve 6c controls the power source 2. More specifically, the solenoid valve 6c controls the tilt angle of the swash plate of the variable displacement pump 2P based on a control signal from the control unit 20.

[0022] [Controller] The controller 10 is the controller of the working machine 1. The controller 10 outputs signals for controlling the working implement, the lower traveling body, and the upper swing body of the working machine 1. The controller 10 outputs a drive control signal to the power source 2 to control the power source 2. When an abnormality occurs inside the controller 10, the controller 10 outputs a cutoff control signal to cut off the power supply from the battery 4. When it is determined that an abnormality has occurred in the power supply circuit connecting the controller 10 and the solenoid valve 6, the controller 10 outputs a command to control the power source 2 so as to limit the operation of the working implement. The controller 10 has a control unit 20. Electric signal lines 101, 103, 104, and 105 are electrically connected to the controller 10. Incidentally, when it is determined that an abnormality has occurred in the power supply circuit connecting the main controller 10 and the solenoid valve 6, the main controller 10 may output a command to control the power source 2 so as to limit the operations of the working implement, the lower traveling body, and the upper swing body.

[0023] In the present disclosure, when the controller 10 determines that an abnormality has occurred in the power supply circuit connecting the controller 10 and the solenoid valve 6, the controller 10 outputs a command to control the engine 2E to reduce its rotational speed. In the present disclosure, when the controller 10 determines that an abnormality has occurred in at least any one of the power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, for example, the controller 10 outputs a command to control the power source controller 30 so that the rotational speed of the engine 2E becomes equivalent to the low idle speed.

[0024] In the present disclosure, when the controller 10 determines that an abnormality has occurred in the power supply circuit connecting the controller 10 and the solenoid valve 6, the controller 10 outputs a command to control the discharge amount of the variable displacement pump 2P to decrease. In the present disclosure, when the controller 10 determines that an abnormality has occurred in at least any one of the power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, for example, the controller 10 outputs a command to control the discharge amount from the variable displacement pump 2P to be minimized.

[0025] In the present disclosure, when the key of the working machine 1 is operated, the controller 10 determines an abnormality in at least any one of the power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c. The operation of the key of the working machine 1 is, for example, when the key is turned ON or when the key is turned OFF. When the key is turned ON, it is the start time of the work of the working machine 1. When the key is turned OFF, it is the end time of the work of the working machine 1.

[0026] The controller 10 includes switching elements 11F, 13F, 14F, and 15F, diodes 11D, 13D, 14D, 15D, 16D, 17D, and 18D, and grounds 16G, 17G, and 18G.

[0027] The switching elements 11F, 13F, 14F, and 15F switch between the conducting state and the non-conducting state of the circuit based on the command of the control unit 20. The switching elements 11F, 13F, 14F, and 15F are, for example, FET (Field Effect Transistor) or transistors, etc.

[0028] The switching element 11F is provided to supply or cut off the power from the battery 4. The switching element 11F is arranged between the downstream side of the battery 4 and the upstream side of the solenoid valve 6. The gate of the switching element 11F is connected to the control unit 20. When the switching element 11F is in the conductive state, power is supplied to the downstream side of the electrical signal line 101. When the switching element 11F is in the non-conductive state, the supply of power to the downstream side of the electrical signal line 101 is cut off.

[0029] More specifically, when an on electrical signal is input to the switching element 11F as a switching signal, the supply of power to the solenoid valve 6 becomes possible. When an off electrical signal is input to the switching element 11F as a switching signal, the supply of power to the solenoid valve 6 is cut off.

[0030] The switching element 13F is provided to drive the solenoid valve 6c. The switching element 13F is provided to switch the supply of power to the solenoid valve 6c according to a command from the control unit 20. The switching element 13F is arranged between the terminal 101a and the ground 16G. The gate of the switching element 13F is connected to the control unit 20. When an abnormality such as a sky connection occurs, the switching element 13F becomes non-conductive and cuts off the supply of power to the solenoid valve 6c.

[0031] The switching element 14F is provided to drive the solenoid valve 6a. The switching element 14F is provided to switch the supply of power to the solenoid valve 6a according to a command from the control unit 20. The switching element 14F is arranged between the terminal 101b and the ground 17G. The gate of the switching element 14F is connected to the control unit 20. When an abnormality such as a sky connection occurs, the switching element 14F becomes non-conductive and cuts off the supply of power to the solenoid valve 6a.

[0032] The switching element 15F is provided to drive the solenoid valve 6b. The switching element 15F is provided to switch the supply of power to the solenoid valve 6b in response to a command from the control unit 20. The switching element 15F is disposed between the terminal 101c and the ground 18G. The gate of the switching element 15F is connected to the control unit 20. When an abnormality such as an open circuit occurs, the switching element 15F becomes non-conductive and cuts off the supply of power to the solenoid valve 6b.

[0033] The electrical signal line 101 electrically connects the battery 4 and the controller 10. The electrical signal line 101 electrically connects the battery 4 and the control unit 20. The switching element 11F is connected to the electrical signal line 101 from the battery 4 side.

[0034] The terminal 101a electrically connects the downstream side of the switching element 11F and the upstream side of the switching element 13F. The terminal 101b electrically connects the downstream side of the switching element 11F and the upstream side of the switching element 14F. The terminal 101c electrically connects the downstream side of the switching element 11F and the upstream side of the switching element 15F.

[0035] The electrical signal line 101i electrically connects between the downstream side of the battery 4 and the upstream side of the switching element 11F and the control unit 20.

[0036] The electrical signal line 101j electrically connects between the downstream side of the switching element 11F and the upstream side of the terminal 101a and the control unit 20.

[0037] The electrical signal line 102 electrically connects the power source 2 and the power source controller 30.

[0038] The electrical signal line 103 connects the downstream side of the switching element 13F and the upstream side of the solenoid valve 6c. The electrical signal line 103 electrically connects the controller 10 and the solenoid valve 6c. The electrical signal line 103 is a power supply circuit that connects the controller 10 and the solenoid valve 6c.

[0039] The electrical signal line 104 connects the downstream side of the switching element 14F and the upstream side of the solenoid valve 6a. The electrical signal line 104 electrically connects the controller 10 and the solenoid valve 6a. The electrical signal line 104 is a power supply circuit that connects the controller 10 and the solenoid valve 6a.

[0040] The electrical signal line 105 connects the downstream side of the switching element 15F and the upstream side of the solenoid valve 6b. The electrical signal line 105 electrically connects the controller 10 and the solenoid valve 6b. The electrical signal line 105 is a power supply circuit that connects the controller 10 and the solenoid valve 6b.

[0041] The electrical signal line 106 electrically connects the downstream side of the switching element 13F and the control unit 20. The electrical signal line 106 is electrically connected to the electrical signal line 103.

[0042] The electrical signal line 107 electrically connects the downstream side of the switching element 14F and the control unit 20. The electrical signal line 107 is electrically connected to the electrical signal line 104.

[0043] The electrical signal line 108 electrically connects the downstream side of the switching element 15F and the control unit 20. The electrical signal line 108 is electrically connected to the electrical signal line 105.

[0044] [Control Unit] The control unit 20 is supplied with power from the battery 4. The control unit 20 receives a signal from the operating device 5. The control unit 20 outputs a signal to the power source controller 30. The control unit 20 includes an abnormality monitoring unit 21, a cutoff control unit 22, a drive control unit 23, and an output unit 24.

[0045] The abnormality monitoring unit 21 monitors abnormalities such as an open circuit inside the controller 10. The abnormality monitoring unit 21 monitors, for example, the failures of the switching elements 11F, 13F, 14F, and 15F provided inside the controller 10. Any known method can be used to determine the failure of the switching element.

[0046] The abnormality monitoring unit 21 monitors abnormalities such as open circuits in the power supply circuit outside the controller 10. The abnormality monitoring unit 21 monitors the occurrence of abnormalities such as open circuits in the power supply circuit connecting the controller 10 and the solenoid valve 6. As an example of an open circuit, as shown by the broken line A in FIG. 1, the electrical signal line 101 between the controller 10 and the battery 4 and the electrical signal line 103 of the solenoid valve 6c are in an electrically conductive state. The abnormality monitoring unit 21 monitors the voltage between the controller 10 and the solenoid valves 6a, 6b, and 6c. When the power supply from the electrical signal lines 103, 104, and 105, which are the power supply circuits, to the solenoid valve 6a, 6b, or 6c is cut off under the control of the control unit 20, and a voltage equal to or higher than the threshold value is applied to the solenoid valve 6a, 6b, or 6c, the abnormality monitoring unit 21 determines that an abnormality has occurred. When it is determined that the "feedback voltage is equal to or higher than the threshold value" in a state where the power supply from the electrical signal lines 103, 104, and 105, which are the power supply circuits, to the solenoid valve 6a, 6b, or 6c is cut off under the control of the control unit 20, the abnormality monitoring unit 21 determines that an abnormality such as an open circuit has occurred. Note that the detection of the feedback voltage may be obtained, for example, by converting the current flowing through the electrical signal line 103 into a voltage by the controller 10 and inputting and determining the converted voltage value by the CPU.

[0047] The monitoring of abnormalities in the external power supply circuit of the controller 10 by the abnormality monitoring unit 21 may be executed as a daily process. In the present disclosure, when the key of the working machine 1 is operated, the abnormality monitoring unit 21 monitors the occurrence of abnormalities such as open circuits in at least any one of the electric signal lines 103, 104, and 105, which are power supply circuits connecting the controller 10 to the solenoid valves 6a, 6b, and 6c respectively. The operation of the key of the working machine 1 means, for example, when the key is turned on or when the key is turned off. When the key is turned on, it is the start time of the operation of the working machine 1. Thereby, abnormalities of the working machine 1 can be detected at the start of work. When the key is turned off, it is the end time of the operation of the working machine 1. Abnormalities of the working machine 1 can be detected at the end of work. In this case, before the start of the next work, it is possible to request inspection and repair of the working machine 1 by a service technician who performs maintenance.

[0048] The cutoff control unit 22 controls the supply of power from the battery 4. More specifically, the cutoff control unit 22 switches between on and off of the switching element 11F. When the abnormality monitoring unit 21 detects an abnormality such as an open circuit inside the controller 10, the cutoff control unit 22 outputs an off electrical signal as a switching signal to the switching element 11F in order to cut off the power supply from the battery 4. Note that when the abnormality monitoring unit 21 does not detect an abnormality such as an open circuit inside the controller 10, the cutoff control unit 22 outputs an on electrical signal as a switching signal to the switching element 11F.

[0049] The drive control unit 23 controls the solenoid valve 6a. More specifically, the drive control unit 23 switches between on and off of the switching element 14F. When the abnormality monitoring unit 21 detects an abnormality such as an open circuit inside the controller 10, the drive control unit 23 outputs an off electrical signal as a switching signal to the switching element 14F in order to cut off the solenoid valve 6a.

[0050] The drive control unit 23 controls the solenoid valve 6b. More specifically, the drive control unit 23 switches the on and off states of the switching element 15F. When the abnormality monitoring unit 21 detects an abnormality such as an open circuit inside the controller 10, the drive control unit 23 outputs an off electrical signal as a switching signal to the switching element 15F in order to cut off the solenoid valve 6b.

[0051] The drive control unit 23 controls the solenoid valve 6c. More specifically, the drive control unit 23 switches the on and off states of the switching element 13F. When the abnormality monitoring unit 21 detects an abnormality such as an open circuit inside the controller 10, the drive control unit 23 outputs an off electrical signal as a switching signal to the switching element 13F in order to cut off the solenoid valve 6c.

[0052] The drive control unit 23 controls at least one of the solenoid valve 6a, the solenoid valve 6b, and the solenoid valve 6c based on the control signal output from the operating device 5.

[0053] The output unit 24 outputs a command to control the power source 2 so as to suppress it to the power source controller 30. More specifically, when the abnormality monitoring unit 21 determines that an abnormality has occurred in the power supply circuit connecting the controller 10 and the solenoid valve 6, the output unit 24 outputs a command to control the power source 2 so as to limit the operation of the work machine to the power source controller 30. In the present disclosure, when the abnormality monitoring unit 21 determines that an abnormality has occurred in at least one of the electrical signal line 103, the electrical signal line 104, and the electrical signal line 105, which are the power supply circuits connecting the controller 10 and each of the solenoid valves 6a, 6b, and 6c, the output unit 24 outputs a command to control the power source 2 so as to limit the operations of the work machine, the lower traveling body, and the upper swing body to the power source controller 30.

[0054] In the present disclosure, when it is determined that an abnormality has occurred in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the output unit 24 to the controller 10 and each of the solenoid valves 6a, 6b, and 6c, the output unit 24 outputs a command to control so as to decrease the rotational speed of the engine 2E. In the present disclosure, when the abnormality monitoring unit 21 determines that an abnormality has occurred in at least any one of the power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, for example, the output unit 24 outputs a command to control so that the rotational speed of the engine 2E becomes equivalent to low idle.

[0055] In the present disclosure, when it is determined that an abnormality has occurred in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the output unit 24 to the controller 10 and each of the solenoid valves 6a, 6b, and 6c, the output unit 24 outputs a command to control so as to decrease the discharge amount of the variable displacement pump 2P. In the present disclosure, when the abnormality monitoring unit 21 determines that an abnormality has occurred in at least any one of the power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, for example, the output unit 24 outputs a command to control so that the discharge amount from the variable displacement pump 2P becomes minimum.

[0056] [Power source controller] The power source controller 30 is a controller that controls the power source 2. The power source controller 30 is electrically connected to the control unit 20 and the power source 2. An electric signal line 102 is electrically connected to the power source controller 30. The power source controller 30 outputs a control signal for controlling the power source 2. The power source controller 30 is provided for each power source 2. For example, when the power source 2 is the engine 2E, the power source controller 30 is an engine controller. For example, when the power source 2 is a generator, the power source controller 30 is a generator controller. For example, when the power source 2 is a fuel cell, the power source controller 30 is a fuel cell controller.

[0057] When the power source controller 30 receives a command from the output unit 24 of the control unit 20, it outputs a control signal to the power source 2 to control the suppression of the power source 2. When the abnormality monitoring unit 21 determines that an abnormality has occurred in the power supply circuit connecting the controller 10 and the solenoid valve 6, a command is input to the power source controller 30 from the output unit 24.

[0058] Based on the command from the output unit 24, the power source controller 30 outputs a control signal to the power source 2 to control the power source 2 so as to limit the operation of the work machine.

[0059] In the present disclosure, when the abnormality monitoring unit 21 of the control unit 20 determines that an abnormality has occurred in at least any one of the electric signal lines 103, 104, and 105, which are power supply circuits connecting the controller 10 and the solenoid valves 6a, 6b, and 6c respectively, the power source controller 30 outputs a control signal to the power source 2 to control the reduction of the engine speed of the engine 2E. In the present disclosure, based on the command from the output unit 24, the power source controller 30 outputs a control signal to the power source 2 to control the engine speed of the engine 2E to be equivalent to low idle, for example.

[0060] In the present disclosure, when the abnormality monitoring unit 21 of the control unit 20 determines that an abnormality has occurred in at least any one of the electric signal lines 103, 104, and 105, which are power supply circuits connecting the controller 10 and the solenoid valves 6a, 6b, and 6c respectively, the power source controller 30 outputs a control signal to the power source 2 to control the reduction of the discharge amount of the variable displacement pump 2P. In the present disclosure, based on the command from the output unit 24, the power source controller 30 outputs a control signal to the power source 2 to control the discharge amount from the variable displacement pump 2P to be minimized, for example.

[0061] Based on the command from the output unit 24, the power source controller 30 outputs a control signal to the power source 2 to control the power source 2 so as to limit the operations of the work machine, the lower traveling body, and the upper revolving body.

[0062] [Computer system] FIG. 2 is a block diagram showing a computer system 1000 according to the first embodiment. The above-described controller 60 includes the computer system 1000. The computer system 1000 includes a processor 1001 such as a CPU (Central Processing Unit), a main memory 1002 including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), a storage 1003, and an interface 1004 including an input / output circuit. The functions of the above-described controller 10 are stored in the storage 1003 as a program. The processor 1001 reads the program from the storage 1003, expands it in the main memory 1002, and executes the above-described processing according to the program. Note that the program may be distributed to the computer system 1000 via a network.

[0063] [Control processing of a machine tool] Next, with reference to the flowchart shown in FIG. 3, the procedure of the processing of the embodiment will be described. FIG. 3 is a flowchart showing a control method performed by the controller 10 of the machine tool 1 according to the first embodiment. In the present disclosure, the processing shown in FIG. 3 is executed when the key of the machine tool 1 is turned ON or OFF.

[0064] The abnormality monitoring unit 21 determines whether there is an abnormality in the power supply circuit connecting the controller 10, which is the power source, and the electromagnetic valve 6 (step S101). More specifically, the abnormality monitoring unit 21 determines that an abnormality has occurred when a voltage equal to or higher than the threshold value is applied to the solenoid valve 6a, the solenoid valve 6b, or the solenoid valve 6c in a state where the power supply from the electric signal lines 103, 104, and 105, which are the power supply circuits, to the solenoid valve 6a, the solenoid valve 6b, or the solenoid valve 6c is cut off under the control of the control unit 20. The turning control unit 11 determines that an abnormality has occurred when it detects that "the feedback voltage is equal to or higher than the threshold value" in a state where the power supply from the electric signal lines 103, 104, and 105, which are the power supply circuits, to the solenoid valve 6a, the solenoid valve 6b, or the solenoid valve 6c is cut off under the control of the control unit 20. When the abnormality monitoring unit 21 determines that there is an abnormality (Yes in step S101), it proceeds to step S102. When the abnormality monitoring unit 21 determines that there is no abnormality (No in step S101), the process ends.

[0065] When it is determined that there is an abnormality (Yes in step S101), the output unit 24 outputs a command for controlling the power source 2 to the power source controller 30. More specifically, the output unit 24 outputs, for example, a command for controlling the engine speed of the engine 2E to be equivalent to low idle. The output unit 24 outputs, for example, a command for controlling the discharge amount from the variable displacement pump 2P to be minimized.

[0066] When a command for controlling the power source 2 is output from the output unit 24 to the power source controller 30, the operator is notified that an abnormality has occurred in the power supply circuit outside the controller 10. For example, a message image or the like notifying of the occurrence of an abnormality in the power supply circuit outside the controller 10 is output to a monitor provided in the cab of the work machine 1. For example, a buzzer provided in the cab of the work machine 1 is sounded to notify the operator of the occurrence of an abnormality in the power supply circuit outside the controller 10. The operator can confirm that the operations of the working implement, the lower traveling body, and the upper revolving body of the work machine 1 are restricted.

[0067] Thus, in the present disclosure, when the controller 10 determines that an abnormality has occurred in a power supply circuit outside the controller 10, in other words, in the power supply circuit connecting the controller 10 and the solenoid valve 6, a command for controlling the power source 2 is output so as to limit the operations of the work machine, the lower traveling body, and the upper revolving body. The work machine 1 is restricted in operation to the same extent as in the low idle state, and operations such as excavation are restricted. The operator can move the work machine 1 to a safe location.

[0068] [Effect] As described above, in the present disclosure, when it is determined that an abnormality has occurred in at least any one of the electric signal lines 103, 104, and 105, which are power supply circuits connecting the controller 10 to the solenoid valves 6a, 6b, and 6c respectively, a command for controlling the power source 2 is output so as to limit the operations of the work machine, the lower traveling body, and the upper revolving body. According to the present disclosure, when an abnormality occurs in a power supply circuit outside the controller 10, the power source 2 can be controlled to limit the operations of the work machine, the lower traveling body, and the upper revolving body. Thus, according to the present disclosure, in addition to the case where an abnormality occurs inside the controller 10, when an abnormality occurs in a power supply circuit outside the controller 10, the work machine 1 can be controlled to further enhance safety.

[0069] In the present disclosure, when it is determined that an abnormality has occurred in at least any one of the electric signal lines 103, 104, and 105, which are power supply circuits connecting the controller 10 to the solenoid valves 6a, 6b, and 6c respectively, a command for controlling the engine 2E to have a low idle speed is output. According to the present disclosure, by suppressing the rotational speed of the engine 2E, the operations of the work machine, the lower traveling body, and the upper revolving body can be restricted.

[0070] In the present disclosure, when it is determined that an abnormality has occurred in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, a command is output to control the discharge amount from the variable displacement pump 2P to be minimized. According to the present disclosure, by restricting the discharge amount from the variable displacement pump 2P, the operations of the work implement, the lower traveling body, and the upper slewing body can be restricted.

[0071] In the present disclosure, when the key of the work machine 1 is operated, an abnormality in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c, is determined. According to the present disclosure, at the start or end of the operation of the work machine 1, an abnormality in the power supply circuit outside the controller 10 can be determined. If an abnormality is determined at the start of the operation, operations such as excavation by the work machine 1 can be prevented from being performed. In this case, it is possible to suppress the work machine 1 from malfunctioning during the operation. If an abnormality is determined at the end of the operation, the service technician who performs maintenance can be requested to inspect and repair the work machine 1 by the next start of the operation.

[0072] In the present disclosure, the notification unit notifies that an abnormality has occurred in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the controller 10 to each of the solenoid valves 6a, 6b, and 6c. According to the present disclosure, the operator can confirm that the operations of the work implement, the lower traveling body, and the upper slewing body of the work machine 1 are restricted.

[0073] (Second Embodiment) FIG. 4 is a schematic block diagram of a work machine 1A according to the second embodiment. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof is simplified or omitted.

[0074] The working machine 1A includes a controller 10, a power source controller 30A, and a secondary controller 40A.

[0075] The control unit 20 of the controller 10 includes an abnormality monitoring unit 21, a cutoff control unit 22, and a drive control unit 23. The abnormality monitoring unit 21 has a function of monitoring abnormalities such as internal short circuits in the controller 10 among the functions of the abnormality monitoring unit 21 in the first embodiment. The cutoff control unit 22 and the drive control unit 23 have the same functions as those in the first embodiment.

[0076] The power source controller 30A is electrically connected to the secondary controller 40A and the power source 2. The power source controller 30A outputs a control signal for controlling the power source 2 based on a control signal from the secondary controller 40A.

[0077] [Secondary Controller] The secondary controller 40A includes an abnormality monitoring unit 41A and an output unit 42A. The solenoid valve 6aA is electrically connected to the secondary controller 40A via an electric signal line 107A connected to the electric signal line 104. The solenoid valve 6bA is electrically connected to the secondary controller 40A via an electric signal line 108A connected to the electric signal line 105. The solenoid valve 6cA is electrically connected to the secondary controller 40A via an electric signal line 106A connected to the electric signal line 103. The secondary controller 40A receives signals from the solenoid valve 6aA, the solenoid valve 6bA, and the solenoid valve 6cA.

[0078] The abnormality monitoring unit 41A has a function of monitoring abnormalities in the power supply circuit outside the controller 10 among the functions of the abnormality monitoring unit 21 in the first embodiment. In the present disclosure, the abnormality monitoring unit 41A determines an abnormality in at least any one of the electric signal line 103, the electric signal line 104, and the electric signal line 105, which are power supply circuits connecting the controller 10 to the solenoid valve 6aA, the solenoid valve 6bA, and the solenoid valve 6cA, respectively.

[0079] The output unit 42A has the same function as the output unit 24 in the first embodiment.

[0080] As described above, in the present disclosure, the secondary controller 40A can detect that an abnormality has occurred in the power supply circuit outside the controller 10. According to the present disclosure, in addition to the case where an abnormality occurs inside the controller 10, when an abnormality occurs in the power supply circuit outside the controller 10, the working machine 1A can be controlled to further enhance safety.

Explanation of Reference Signs

[0081] 1... Working machine, 2... Power source, 2E... Engine, 2P... Variable displacement pump, 2X... Drive shaft, 3... Hydraulic actuator, 4... Battery, 5... Operating device, 6, 6a, 6b, 6c... Solenoid valve, 10... Controller (first controller), 11D, 13D, 14D, 15D, 16D, 17D, 18D... Diode, 11F, 13F, 14F, 15F... Switching element, 16G, 17G, 18G... Ground, 20... Control unit, 21... Abnormality monitoring unit, 22... Cut-off control unit, 23... Drive control unit, 24... Output unit, 30... Power source controller, 101, 101i, 101j, 102, 103, 104, 105, 106, 107, 108... Electrical signal line, 101a, 101b, 101c... Terminal.

Claims

1. A working machine having a working implement, a power source that outputs a driving force for operating the working implement, a controller, a solenoid valve controlled by the controller, and comprising: when the controller determines that an abnormality has occurred in a power supply circuit connecting the controller and the solenoid valve, the controller outputs a command to control the power source so as to limit the operation of the working implement. A working machine.

2. The power source is an engine, when the controller determines that an abnormality has occurred in a power supply circuit connecting the controller and the solenoid valve, the controller outputs a command to control the engine to reduce its rotational speed. The working machine according to Claim 1.

3. The power source is a variable displacement pump, when the controller determines that an abnormality has occurred in a power supply circuit connecting the controller and the solenoid valve, the controller outputs a command to control the variable displacement pump to reduce its discharge volume. The working machine according to Claim 1.

4. The controller suppresses the discharge volume by changing the tilt angle of the swash plate of the variable displacement pump. The working machine according to Claim 3.

5. When the key of the working machine is operated, the controller determines an abnormality in the power supply circuit between the controller and the solenoid valve. The working machine according to any one of Claims 1 to 4.

6. When the key of the working machine is operated, it is when the key is ON. The working machine according to Claim 5.

7. When the key of the working machine is operated, it is when the key is OFF. The working machine according to Claim 5.

8. An informing unit that informs that an abnormality has occurred in the power supply circuit connecting the controller and the solenoid valve. The working machine according to any one of Claims 1 to 7, comprising the same.

9. The power source outputs a driving force for operating the working implement, the lower traveling body, and the upper revolving body. When the controller determines that an abnormality has occurred in a power supply circuit connecting the controller and the solenoid valve, the controller outputs a command to control the power source so as to limit the operations of the working implement, the lower traveling body, and the upper revolving body. The working machine according to any one of Claims 1 to 8.

10. A control method for a working machine having a working implement, When it is determined that an abnormality has occurred in the power supply circuit connecting the controller for controlling the solenoid valve and the solenoid valve, a command is output to control the power source so as to limit the operation of the work machine. A control method for a work machine.

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