Work machine

Abstract

A first pump and a second pump are driven by an engine. A hydraulic actuator is driven by working oil supplied from the first pump. A control valve controls a flow of the working oil supplied to the hydraulic actuator. A solenoid valve reduces a pressure of the second pump to generate a pilot pressure for operating the control valve. A control device controls the solenoid valve. An engine operating portion is operable to start the engine. A rotation speed sensor detects a rotation speed of the engine. The control device applies a drive current to the solenoid valve to drive the solenoid valve when it is determined from a detection result of the rotation speed sensor that the engine is in a stopped state and when a current application condition for applying a current to the engine operating portion in a state where a start operation is not performed by the engine operating portion is satisfied.

Description

Technical Field

[0001] This invention relates to hydraulic excavators and other operating machinery that suppress blockages between the valve core and the valve body. Background Technology

[0002] It is known that in a device having a solenoid valve that slides relative to the valve body according to a control current command and outputs pressure oil corresponding to the movement position of the solenoid valve, and a control device that operates according to the pressure oil output from the solenoid valve, a phenomenon of foreign matter mixed in with the pressure oil accumulating between the valve spool and the valve body, i.e., blockage, is prevented (see Patent Document 1).

[0003] In the technology described in Patent Document 1, the following is shown: a correspondence between the time width and the current value of the current command to the solenoid valve is preset within the range where the controlled device is not in operation, and a current command for clogging prevention is provided to the solenoid valve according to the preset correspondence. Furthermore, the following is shown: hydraulic actuators such as hydraulic cylinders, hydraulic pumps, and hydraulic motors are used as controlled objects, and clogging prevention processing is performed within the range where these hydraulic actuators are not in operation.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2001-324047 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the technology described in Patent Document 1, during engine operation, a blockage prevention process is performed within the range where the hydraulic actuator is not operating. Therefore, there is a limitation in increasing the movement of the solenoid valve spool. Consequently, in the technology described in Patent Document 1, it may not be possible to sufficiently remove foreign matter between the solenoid valve spool and the retaining member that keeps the spool sliding freely. As a result, the solenoid valve may become stuck due to the foreign matter, potentially causing malfunction of the hydraulic actuator. Furthermore, in order to sufficiently remove foreign matter, if the movement of the solenoid valve spool is increased in the technology described in Patent Document 1, the operation of the solenoid valve used for removing foreign matter may affect the operation of the hydraulic actuator.

[0009] The purpose of this invention is to provide a working machine that can more effectively remove foreign objects from a solenoid valve without affecting the operation of the hydraulic actuator.

[0010] Methods for solving problems

[0011] One aspect of the present invention provides a working machine comprising: an engine; a first pump and a second pump driven by the engine; a hydraulic actuator driven by working oil supplied from the first pump; a control valve controlling the flow of working oil supplied from the first pump to the hydraulic actuator; a solenoid valve reducing the pressure of the working oil supplied from the second pump to generate a pilot pressure for operating the control valve; a control device controlling the solenoid valve; an engine operating unit capable of starting the engine; and a speed sensor detecting the engine speed. The control device determines that the engine is in a stopped state based on the detection result of the speed sensor, determines whether a current application condition, including a current application operation to the engine operating unit without starting the engine, is met, and if the current application condition is met, applies a driving current to the solenoid valve to drive the solenoid valve.

[0012] Invention Effects

[0013] According to the present invention, a working machine is provided that can more effectively remove foreign objects from a solenoid valve without affecting the operation of the hydraulic actuator. Attached Figure Description

[0014] Figure 1 This is a side view of the hydraulic excavator according to the first embodiment.

[0015] Figure 2 This is a diagram showing the hydraulic system of the hydraulic excavator according to the first embodiment.

[0016] Figure 3 This is a hardware structure diagram of the operation controller.

[0017] Figure 4 This is a functional block diagram of the operation controller in the first embodiment.

[0018] Figure 5 It is a table that shows the relationship between the engine status, the ignition switch operating position, and the on / off state of the current application indicator.

[0019] Figure 6A This is a timing diagram of the control current supplied from the operation controller of the first embodiment to the solenoid of the electromagnetic proportional valve.

[0020] Figure 6B This is a timing diagram of the control current supplied from the operation controller of the first embodiment (Modified Example 1) to the solenoid of the electromagnetic proportional valve.

[0021] Figure 6C This is a timing diagram of the control current supplied from the operation controller of the first embodiment, variant 2, to the solenoid of the electromagnetic proportional valve.

[0022] Figure 7 This is a functional block diagram of the operation controller in the second embodiment.

[0023] Figure 8 This is a diagram representing the control current characteristic Ic1.

[0024] Figure 9 This is a functional block diagram of the operation controller in the third embodiment.

[0025] Figure 10 This is a diagram representing the control current characteristic Ic2.

[0026] Figure 11 This is a functional block diagram of the operation controller in the fourth embodiment.

[0027] Figure 12 This is a graph representing the applied time characteristic tc.

[0028] Figure 13 This is a functional block diagram of the operation controller in the fifth embodiment. Detailed Implementation

[0029] Referring to the accompanying drawings, the working machinery according to an embodiment of the present invention will be described. In this embodiment, an example of a tracked hydraulic excavator will be described. The working machinery performs civil engineering work, construction work, dismantling work, dredging work, and other operations at the work site.

[0030] <First Implementation>

[0031] Figure 1 This is a side view of the hydraulic excavator 100 according to the first embodiment. Figure 1 As shown, the hydraulic excavator 100 includes a body 105 and a working device 104 mounted on the body 105. The body 105 has a tracked traveling body 102 and a slewing body 103 rotatably mounted on the traveling body 102. The traveling body 102 travels by a pair of left and right tracks driven by a traveling motor 102A. The slewing body 103 is connected to the traveling body 102 via a slewing device having a slewing motor 103A, and is driven by the slewing motor 103A to rotate (slew) relative to the traveling body 102.

[0032] The slewing body 103 has a driver's cab 118 for the operator, and an engine compartment 119 housing an engine 191 as a prime mover and hydraulic equipment such as a hydraulic pump driven by the engine 191. A starter motor 196 for starting the engine 191 is provided in the engine compartment 119 (see reference). Figure 2 ), and a battery 197 that supplies power to various devices. The battery 197 is, for example, an energy storage device having multiple lithium-ion secondary batteries as energy storage elements.

[0033] An ignition switch 188 is installed in the driver's cab 118 (see reference). Figure 2 The engine control unit is capable of starting or stopping the engine 191; and an electrical operating device is provided for operating the hydraulic actuators (111A, 112A, 113A, 103A, 102A) of the working device 104, the rotating body 103, and the traveling body 102. Additionally, a body control controller 120 (see reference) is provided in the driver's cab 118. Figure 2 This is a control device that controls the basic movements of the hydraulic excavator 100; the engine controller 190 (see reference) Figure 2 This is a control device that controls the rotational speed of the engine 191; and an operation controller 150 (see reference). Figure 2 It is a control device that controls the starting, stopping, etc. of the engine 191.

[0034] like Figure 2 As shown, the operation controller 150, body control controller 120, and engine controller 190 are interconnected via an in-vehicle network 109 called CAN (Controller Area Network). Furthermore, the in-vehicle network 109 can also use communication standards other than CAN, such as Ethernet (registered trademark).

[0035] like Figure 1 As shown, the cab 118 is equipped with: a display device 115 that displays images indicating the operating status of the hydraulic excavator 100; and an input device 116 for operating the display device 115, etc. The display device 115 may be a liquid crystal display, an organic EL display, etc., and the input device 116 may have multiple switches and joysticks, etc. Alternatively, the input device 116 may be a touch sensor formed on the display of the display device 115. That is, the hydraulic excavator 100 may also have a touch panel monitor that functions as both the display device 115 and the input device 116.

[0036] The working device 104 is a multi-joint type working device mounted on the slewing body 103, having multiple hydraulic actuators and multiple driven components (front components) driven by the multiple hydraulic actuators. The working device 104 is a structure in which three driven components (boom 111, stick 112, and bucket 113) are connected in series. The base end of the boom 111 is rotatably connected to the front part of the slewing body 103 via a boom pin. The base end of the stick 112 is rotatably connected to the front end of the boom 111 via a stick pin. The bucket 113 is rotatably connected to the front end of the stick 112 via a bucket pin.

[0037] The boom 111 is driven to rotate by the extension and retraction of the boom cylinder 111A, which acts as a hydraulic actuator (hydraulic cylinder). The stick 112 is driven to rotate by the extension and retraction of the stick cylinder 112A, which acts as a hydraulic actuator (hydraulic cylinder). The bucket 113 is driven to rotate by the extension and retraction of the bucket cylinder 113A, which acts as a hydraulic actuator (hydraulic cylinder). By actuating the working device 104, the hydraulic excavator 100 is capable of performing tasks such as excavating sand and soil, leveling, and compacting the ground.

[0038] Figure 2 This diagram illustrates the hydraulic system (hydraulic drive circuit) 106 of the hydraulic excavator 100 according to the first embodiment. Furthermore, hereinafter, the travel motor (hydraulic motor) 102A, swing motor (hydraulic motor) 103A, boom cylinder (hydraulic cylinder) 111A, stick cylinder (hydraulic cylinder) 112A, and bucket cylinder (hydraulic cylinder) 113A mounted on the hydraulic excavator 100 will be collectively referred to as hydraulic actuators. The hydraulic excavator 100 has multiple hydraulic actuators, but... Figure 2 The diagram illustrates, in a representative manner, a hydraulic cylinder 110 (e.g., boom cylinder 111A) for driving the driven components of the working device 104. Additionally, an electrical operating device 180 that operates the hydraulic actuators, and electromagnetic proportional valves 140A, 140B and a directional control valve (also called a flow control valve) 130 that are driven according to the operation of the operating device 180 are provided with multiple hydraulic actuators, but... Figure 2 The diagram, as an example, only illustrates the structure used to control a hydraulic actuator.

[0039] The hydraulic system 106 includes: a main pump 135 serving as a first pump and a pilot pump 136 serving as a second pump; a hydraulic cylinder 110 driven by working oil supplied from the main pump 135 as working fluid; a directional control valve 130, which is a control valve controlling the flow of working oil supplied from the main pump 135 to the hydraulic cylinder 110; electromagnetic proportional valves 140A and 140B, which reduce the pressure of the working oil supplied from the pilot pump 136 to generate a pilot pressure (hereinafter also referred to as the command pilot pressure) for operating the directional control valve 130; and a tank 107 for storing working oil. The directional control valve 130 includes: a pressure-receiving part 131A, which is guided by the command pilot pressure from the electromagnetic proportional valve 140A; and a pressure-receiving part 131B, which is guided by the command pilot pressure from the electromagnetic proportional valve 140B. Hereinafter, the pressure-receiving parts 131A and 131B are also referred to as pressure-receiving part 131. In addition, electromagnetic proportional valves 140A and 140B are also uniformly referred to as electromagnetic proportional valve 140.

[0040] The main pump 135 and pilot pump 136 are connected to and driven by the engine 191, discharging the working oil drawn from the tank 107. The main pump 135 is a variable-capacity hydraulic pump, and the pilot pump 136 is a fixed-capacity hydraulic pump. The engine 191 is the power source of the hydraulic excavator 100, and is composed of an internal combustion engine such as a diesel engine. The speed of the engine 191 is detected by a speed sensor 192, such as a pickup sensor.

[0041] like Figure 4 As schematically shown, the electromagnetic proportional valve 140 is a known electromagnetic proportional pilot pressure reducing valve, comprising: a valve core 142 as a valve body; a sleeve 143, which is a retaining member that holds the valve core 142 in a sliding manner; a solenoid 146, which provides thrust to the valve core 142; and a spring 145, which is a force-applying member that provides a force to the valve core 142 against the thrust of the solenoid 146.

[0042] The sleeve 143 is fixed to the hole in the valve block 144. A T port, an A port, and a P port are formed in the sleeve 143 and the valve block 144. The P port is connected to the pilot pump 136, the T port is connected to the tank 107, and the A port is connected to the pressure-receiving part 131 of the directional control valve 130.

[0043] The valve core 142 has a stroke between the fully closed and fully open positions. In the fully closed position, it cuts off the connection between port P and port A, and connects port A and port T. In the fully open position, it cuts off the connection between port A and port T, maximizing the opening area connecting port P and port A. Furthermore, in... Figure 4 In the diagram, based on the position of the valve core 142, the grooves, notches, holes, etc. formed in the valve core 142, sleeve 143, and valve block 144 to enable communication between the ports are omitted.

[0044] like Figure 2 As shown, the electromagnetic proportional valve 140 generates a command pilot pressure (pilot secondary pressure) by reducing the discharge pressure (pilot primary pressure) of the pilot pump 136, which serves as the pilot hydraulic source. The command pilot pressure generated by the electromagnetic proportional valve 140 is guided to the pressure-receiving part 131 of the directional control valve 130. The electromagnetic proportional valve 140 is controlled according to signals from the operation controller 150 or the body control controller 120.

[0045] The operating device 180 instructs the operation of the working device 104, the rotating body 103 and the traveling body 102 according to the operator's operation, and has an operating lever (operating component) 182 capable of tilting operation and an operating sensor 181 that outputs an operation signal corresponding to the operation amount (operating angle) of the operating lever 182 to the operation controller 150.

[0046] The body control controller 120 receives operating signals from the operation controller 150 via the vehicle network 109. Alternatively, the body control controller 120 can also directly receive operating signals from the operation sensor 181. The body control controller 120 controls the solenoid proportional valve 140 based on the detection results from the operation sensor 181. Furthermore, the body control controller 120 can control the solenoid proportional valve 140 via the operation controller 150, or it can directly output control current to the solenoid proportional valve 140 to control it.

[0047] When the pilot pressure generated by the electromagnetic proportional valve 140A acts on the pressure-receiving portion 131A of the directional control valve 130, which is in the neutral position (N), the directional control valve 130 is driven in one direction, switching from the neutral position (N) to the first position (P1). As a result, pressurized oil discharged from the main pump 135 is guided to the bottom chamber 110b of the hydraulic cylinder 110 (e.g., boom cylinder 111A), and working oil is discharged from the rod chamber 110r to the reservoir 107, causing the hydraulic cylinder 110 (e.g., boom cylinder 111A) to extend. Consequently, the driven component (e.g., boom 111) rotates in the first direction (upward direction).

[0048] When the pilot pressure generated by the electromagnetic proportional valve 140B acts on the pressure-receiving portion 131B of the directional control valve 130, which is in the neutral position (N), the directional control valve 130 is driven in the other direction, switching from the neutral position (N) to the second position (P2). As a result, pressurized oil discharged from the main pump 135 is guided to the rod chamber 110r of the hydraulic cylinder 110 (e.g., boom cylinder 111A), and working oil is discharged from the bottom chamber 110b to the tank 107, causing the hydraulic cylinder 110 (e.g., boom cylinder 111A) to contract. Consequently, the driven component (e.g., boom 111) rotates in the second direction (downward direction).

[0049] Thus, the working oil sprayed from the main pump 135 is supplied to the hydraulic cylinder 110 through the directional control valve 130, and the hydraulic cylinder 110 is driven. In addition, although not shown, the working oil discharged from the main pump 135 is supplied to the rotary motor 103A and the travel motor 102A through the directional control valve 130, and the rotary body 103 and the travel body 102A are driven respectively.

[0050] The door lock lever device 185 includes a door lock lever 187 and an operating position sensor 186 that detects the operating position of the door lock lever 187 and outputs it to the operation controller 150. An electromagnetic switching valve (hereinafter referred to as a locking valve) 141 is installed in the pilot line between the pilot pump 136 and the electromagnetic proportional valve 140. This electromagnetic switching valve switches between a connected position (connecting the pilot line) and a disconnected position (cutting off the connection of the pilot line) according to the operating position of the door lock lever 187.

[0051] When the door lock lever 187 is operated to the lock-out position (lowered position), a communication signal is output from the operation controller 150 to the locking valve 141. This switches the locking valve 141 to the open position. Therefore, when the door lock lever 187 is in the lock-out position, a pilot pressure corresponding to the operation amount of the operating lever 182 is generated by the electromagnetic proportional valve 140, actuating the hydraulic actuator corresponding to the operated lever 182. That is, when the door lock lever 187 is operated to the lock-out position (lowered position), it becomes capable of actuating the actuator based on the operating device 180.

[0052] When the door lock lever 187 is operated to the locked position (raised position), a cut-off signal is output from the operation controller 150 to the locking valve 141. As a result, the locking valve 141 switches to the cut-off position. Consequently, the supply of pilot primary pressure from the pilot pump 136 to the solenoid proportional valve 140 is cut off, and the operation of the operating lever 182 is disabled. That is, when the door lock lever 187 is operated to the locked position (raised position), it becomes a state where the actuator based on the operating device 180 cannot be activated.

[0053] A temperature sensor 189 is installed in tank 107 to detect the temperature of the working oil supplied to the solenoid proportional valve 140. However, the location of the temperature sensor 189 is not limited to tank 107. For example, the temperature sensor 189 can also be installed on the pilot line connecting the pilot pump 136 and the solenoid proportional valve 140.

[0054] In addition to controlling the starting and stopping of the engine 191, the operation controller 150 also controls the electromagnetic proportional valve 140 according to the operating position of the ignition switch 188 and the state of the engine 191. Figure 3 This is a hardware structure diagram of the operation controller 150. (Example) Figure 3 As shown, the operation controller 150 is composed of a computer having a processor 151 such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), or DSP (Digital Signal Processor), volatile memory 152 such as RAM (Random Access Memory), non-volatile memory 153 such as ROM (Read Only Memory), flash memory, or hard disk drive, an input interface 154, an output interface 155, and other peripheral circuits. Furthermore, the operation controller 150 can be composed of a single computer or multiple computers.

[0055] The non-volatile memory 153 stores programs capable of performing various operations. That is, the non-volatile memory 153 is a storage medium capable of reading programs that implement the functions of this embodiment. The processor 151 is a processing device that expands the program stored in the non-volatile memory 153 into the volatile memory 152 and performs operations on it, and performs prescribed operations on signals received from the input interface 154, the volatile memory 152, and the non-volatile memory 153 according to the program.

[0056] Input interface 154 converts the input signal into data that can be processed by processor 151. In addition, output interface 155 generates an output signal corresponding to the calculation result in processor 151, and outputs the signal to a device such as electromagnetic proportional valve 140.

[0057] Although not shown in the figure, the body control controller 120 and the engine controller 190, like the operation controller 150, are composed of a computer with a processor, volatile memory, non-volatile memory, input interface, output interface and other peripheral circuits.

[0058] The body control controller 120 controls the operation of the hydraulic actuator based on the operation signal from the operation sensor 181. The body control controller 120 converts the operation signal from the operation sensor 181 into a lever operation amount. The lever operation amount is represented, for example, by a value of 0% when the lever is neutral and 100% when the lever is at full lever (maximum operation). The body control controller 120 calculates the required pilot pressure for the electromagnetic proportional valve 140 based on the lever operation amount.

[0059] The body control controller 120 converts the required pilot pressure into a control current value for the corresponding electromagnetic proportional valve 140, and outputs the control current to the solenoid 146 of the electromagnetic proportional valve 140 to drive the electromagnetic proportional valve 140. The greater the control current value, the greater the commanded pilot pressure generated by the electromagnetic proportional valve 140. In this embodiment, when the main pump 135 and the pilot pump 136 are driven by the engine 191, if the operator operates the operating device 180, the hydraulic actuator will operate according to the operating direction and amount of the operating device 180.

[0060] The engine controller 190 controls the engine speed of the engine 191 by adjusting the amount of fuel injected into the cylinder of the engine 191 through the fuel injection device. The body control controller 120 is connected to the engine control dial 198, which serves as an engine speed setting device for setting the target speed of the engine 191. The body control controller 120 calculates the target speed of the engine 191 based on the operation signal of the engine control dial 198 located in the cab 118, and outputs it to the engine controller 190.

[0061] A speed sensor 192, which detects the speed of engine 191, is connected to engine controller 190 via a signal line (not shown). Engine controller 190 controls the fuel injection device so that the actual speed of engine 191 detected by speed sensor 192 becomes the target speed input from vehicle body control controller 120.

[0062] The operation controller 150 is connected to the ignition switch 188 and detects the operating position of the ignition switch 188. Based on the operating position of the ignition switch 188, the operation controller 150 controls the starting and stopping of the body control controller 120 and the engine controller 190. Additionally, based on the operating position of the ignition switch 188, the operation controller 150 controls the starting and stopping of the engine 191.

[0063] Ignition switch 188 can cut off the power supply from battery 197 (see reference). Figure 1 The ignition switch 188 in this embodiment is used for several operations: disconnecting the power supply to the engine controller 190, connecting the power supply from the battery 197 to the engine controller 190, and starting the engine 191 via the starter motor 196. The connecting operation is used to supply power to the engine controller 190, which is a prerequisite for starting the engine 191, and is one of the operations used to start the engine 191. The ignition switch 188 in this embodiment is an engine key switch that allows the engine key to be inserted into the keyhole of the lock cylinder and rotated to various operating positions.

[0064] The operation controller 150 and the battery 197 are typically connected via normally closed relays that are in a closed state. The operation controller 150 is connected to the starting relay 193, the ACC relay 194, and the IG relay 195.

[0065] The ignition switch 188 has four operating positions: off (stop), ACC, on (operation), and start (start position). The operation controller 150 controls the opening and closing of various relays 193, 194, and 195 according to the operating position of the ignition switch 188.

[0066] The starter relay 193 is used to supply or disconnect power from the battery 197 to the starter motor 196, which starts the engine 191. When the starter relay 193 is on (i.e., in the closed state), power is supplied from the battery 197 to the starter motor 196, causing the starter motor 196 to operate and drive the engine 191. That is, cranking of the engine 191 is performed based on the starter motor 196. When the starter relay 193 is off (i.e., in the open state), the power supply from the battery 197 to the starter motor 196 is cut off.

[0067] ACC relay 194 is a relay used to supply or disconnect power from battery 197 to devices in an accessory (ACC) system, such as a radio (not shown), audio equipment (not shown), display device 115, and accessory controllers (not shown) that control these devices. When ACC relay 194 is on, i.e., when ACC relay 194 is in the closed state, power is supplied from battery 197 to the devices in the accessory system. When ACC relay 194 is off, i.e., when ACC relay 194 is in the open state, the power supply from battery 197 to the devices in the accessory system is disconnected.

[0068] IG relay 195 is a relay used to supply or disconnect power from battery 197 to devices in the ignition (IG) system, such as air conditioning (not shown), body control controller 120, and engine controller 190. When IG relay 195 is on, i.e., when IG relay 195 is in the closed state, power is supplied from battery 197 to the devices in the ignition system. When IG relay 195 is off, i.e., when IG relay 195 is in the open state, the power supply from battery 197 to the devices in the ignition system is disconnected.

[0069] However, in Figure 2 In the hydraulic system 106 shown, the working oil contains foreign objects such as metal fragments and dust. To remove these foreign objects, a filter (not shown) is installed in the hydraulic system 106. However, foreign objects smaller than the filter's opening area cannot pass through the filter and flow into the various hydraulic devices within the hydraulic system 106. When foreign objects flow into the solenoid proportional valve 140, causing accumulation (clogging) in the gap between the valve core 142 and the sleeve 143, sometimes the valve core 142's movement is restricted by the foreign objects, resulting in a stuck phenomenon (valve stick).

[0070] Therefore, when the operation controller 150 of this embodiment performs a start-up operation for the hydraulic excavator 100 as an operation to start the engine 191, it drives the electromagnetic proportional valve 140 in the stopped state before the engine 191 starts. This prevents the accumulation of foreign objects in the electromagnetic proportional valve 140 without affecting the vehicle's behavior. Hereinafter, the function of the control performed by the operation controller 150 to prevent the electromagnetic proportional valve 140 from sticking (hereinafter also referred to as sticking prevention control) will be described in detail.

[0071] Figure 4 This is a functional block diagram of the operation controller 150 according to the first embodiment. For example... Figure 4 As shown, the operation controller 150 functions as the engine status determination unit 161, the switch operation determination unit 162, the current application condition determination unit 163, the solenoid valve control unit 164, and the relay control unit 165 by executing the program stored in the non-volatile memory 153.

[0072] The engine state determination unit 161 determines whether the engine 191 is in a stopped state or an operating state based on the detection result of the speed sensor 192. If the engine speed N detected by the speed sensor 192 is below the speed threshold N0, the engine state determination unit 161 determines that the engine 191 is in a stopped state. If the engine speed N detected by the speed sensor 192 is above the speed threshold N1, the engine state determination unit 161 determines that the engine 191 is in an operating state.

[0073] The speed threshold N0 is a threshold used to determine whether the engine 191 is in a stopped state, and it is pre-stored in the non-volatile memory 153 of the operation controller 150 (see reference). Figure 3 The speed threshold N0 is, for example, greater than the speed that can be controlled by the engine control dial 198 (see reference). Figure 2 The minimum speed setting is a value smaller than 0 (zero) (for example, 0 to several rpm).

[0074] Speed ​​threshold N1 is a threshold used to determine whether engine 191 is in an operating state, and is pre-stored in the non-volatile memory 153 of the operation controller 150 (see reference). Figure 3 In this embodiment, the "operational state" of engine 191 refers to the state after engine 191 has been started by cranking the starter motor 196, a state in which the operation of engine 191 is controlled by engine controller 190. The speed threshold N1 is, for example, a dial 198 that can be controlled by the engine (see reference). Figure 2 The value below the set minimum speed is set to a value greater than the maximum crank starting speed of the starter motor 196.

[0075] The switch operation determination unit 162 determines whether the ignition switch 188 has been operated to the off position, ACC position, on position, or start position. Furthermore, operating the ignition switch 188 to the off position is synonymous with performing an off operation via the ignition switch 188. Operating the ignition switch 188 to the ACC position is synonymous with performing an ACC operation via the ignition switch 188. Operating the ignition switch 188 to the on position is synonymous with performing an on operation via the ignition switch 188, but there are two modes for this on position: the case where it is operated to the on position after being operated to the start position (described later, after a crank start operation), and the case where it is operated to the on position without any operation to the start position. Operating the ignition switch 188 to the start position is synonymous with performing a start operation (starting operation) via the ignition switch 188. In other words, the switch operation determination unit 162 determines whether an off operation, an ACC operation, an on operation, or a start operation has been performed via the ignition switch 188.

[0076] When the switch operation determination unit 162 determines that the ignition switch 188 is in the ACC position, the relay control unit 165 outputs a command to the ACC relay 194 to turn on the ACC relay 194. When the switch operation determination unit 162 determines that the ignition switch 188 is in the ON position, the relay control unit 165 outputs a command to the IG relay 195 to turn on the IG relay 195.

[0077] When the switch operation determination unit 162 determines that the ignition switch 188 is in the start position, the relay control unit 165 outputs a command to the start relay 193 to turn on the start relay 193. The command to turn on the start relay 193 is also output to the engine controller 190, and the starting control of the engine 191 using the fuel injection device is started through the engine controller 190.

[0078] When the switch operation determination unit 162 determines that the ignition switch 188 is in the ON position, the relay control unit 165 outputs a command to the start relay 193 to disconnect the start relay 193. When the switch operation determination unit 162 determines that the ignition switch 188 is in the ACC position, the relay control unit 165 outputs a command to the IG relay 195 to disconnect the IG relay 195. When the switch operation determination unit 162 determines that the ignition switch 188 is in the OFF position, the relay control unit 165 outputs a command to the ACC relay 194 to disconnect the ACC relay 194.

[0079] Furthermore, although not shown in the diagram, when the engine 191 is in operation, if the switch operation determination unit 162 determines that the ignition switch 188 has been switched from the ON position to the ACC position, the relay control unit 165 outputs an engine stop command to the engine controller 190. Thus, control of the engine 191, which utilizes a fuel injection device, based on the engine controller 190 ends, and the engine 191 stops.

[0080] When the current application condition determination unit 163 is set to off (described later), it determines whether the current application condition is met. The current application condition is met if both conditions 1 and 2 are satisfied, and is not met if at least one of conditions 1 and 2 is not satisfied.

[0081] (Condition 1) The ignition switch 188 was switched to the ON position without going through the ignition switch ground.

[0082] (Condition 2) Engine 191 is in a stopped state.

[0083] In this embodiment, condition 1 is satisfied when the ignition switch 188 is operated to the ON position, and condition 2 is satisfied when the engine speed 191 is below the speed threshold N0.

[0084] When the engine status determination unit 161 determines that the engine 191 is in a stopped state, and the switch operation determination unit 162 determines that the ignition switch 188 has been operated to the on position, the current application condition determination unit 163 determines that the current application condition is met. When the current application condition determination unit 163 determines that the current application condition is met, it sets the current application flag to on.

[0085] If the engine status determination unit 161 determines that the engine 191 is not in a stopped state, the current application condition determination unit 163 determines that the current application condition is not met. Furthermore, if the switch operation determination unit 162 determines that the ignition switch 188 has been operated to a position other than the ON position, the current application condition determination unit 163 also determines that the current application condition is not met. When the current application condition is determined to be not met, the current application condition determination unit 163 maintains the current application flag in the OFF position.

[0086] When the current application condition determination unit 163 is set to "on", it determines whether the current application release condition is met. When the engine status determination unit 161 determines that the engine 191 is in an operating state, the current application condition determination unit 163 determines that the current application release condition is met. When the switch operation determination unit 162 determines that the ignition switch 188 is operated to the ACC position or the off position, the current application condition determination unit 163 determines that the current application release condition is met. When the current application condition determination unit 163 determines that the current application release condition is met, it sets the current application flag to "off".

[0087] If the engine status determination unit 161 determines that the engine 191 is not in operation, and the switch operation determination unit 162 determines that the ignition switch 188 has been operated to the ON or START position, the current application condition determination unit 163 determines that the current application release condition is not met. If the current application release condition is not met, the current application condition determination unit 163 maintains the current application flag as ON.

[0088] When the current application flag is set from closed to open, the solenoid valve control unit 164 applies a drive current to the solenoid proportional valve 140 to drive the solenoid proportional valve 140. Applying a drive current to the solenoid proportional valve 140 means supplying the solenoid proportional valve 140 with the control current I required to drive the valve core 142 (i.e., to move the valve core 142 from the fully closed position).

[0089] In this embodiment, the solenoid valve control unit 164 applies a drive current to the solenoid proportional valve 140 for a predetermined time t0, causing the valve core 142 to move to its full stroke position (fully open position) and remain in that position. The solenoid valve control unit 164 stops applying the drive current to the solenoid proportional valve 140 after the predetermined time t0 has elapsed. Furthermore, the time is measured using the timer function of the operation controller 150.

[0090] The solenoid valve control unit 164 outputs the maximum current Imax, used to move the valve core 142 of the solenoid proportional valve 140 from the fully closed position to the fully open position, as the drive current to the solenoid proportional valve 140 solenoid valve 146. The specified time t0 is predetermined to be approximately 200 msec to 300 msec.

[0091] When the current application flag is set from open to closed, the solenoid valve control unit 164 stops applying the drive current to the solenoid proportional valve 140. Stopping the application of the drive current to the solenoid proportional valve 140 means setting the control current I supplied to the solenoid proportional valve 140 to the minimum current Imin. The minimum current Imin is equivalent to the standby current that keeps the valve core 142 in the fully closed position.

[0092] The following is for reference Figure 5 and Figure 6A Together with the operation of the operator's ignition switch 188, a specific example of the fixation prevention control of the electromagnetic proportional valve 140 when the engine 191 is started in the hydraulic excavator 100 of this embodiment will be described.

[0093] Figure 5 This is a table showing the relationship between the state of engine 191, the operating position of ignition switch 188, and the on / off state of the current application indicator. Figure 6A This is a timing diagram of the control current supplied from the operation controller 150 of the first embodiment to the solenoid 146 of the electromagnetic proportional valve 140. Figure 6A In the figure, the horizontal axis represents the elapsed time t, and the vertical axis represents the magnitude of the control current I supplied to the electromagnetic proportional valve 140.

[0094] When the operator, seated in the cab 118, moves the ignition switch 188 from the off position to the ACC position, power is supplied to the ACC system. This changes the state of the hydraulic excavator 100 from... Figure 5 The state of No.1 changes to state No.2. In states No.1 and No.2, the current application flag is set to off.

[0095] As a preparatory operation to start the engine 191, when the operator moves the ignition switch 188 from the ACC position to the ON position, power is supplied to the IG system, which includes the engine controller 190. This changes the state of the hydraulic excavator 100 from... Figure 5 The state of No.2 changes to state No.3, and the current application condition is met. As a result, the current application flag is set to on.

[0096] like Figure 6A As shown, when the current application flag is set to open, the operation controller 150 changes the control current I supplied to the solenoid 146 of the electromagnetic proportional valve 140 from the minimum current Imin to the maximum current Imax. This causes the valve core 142 of the electromagnetic proportional valve 140 to move from the fully closed position to the fully open position. This allows the valve core 142 of the electromagnetic proportional valve 140 to complete its full stroke from one end to the other, thus effectively removing foreign objects from the electromagnetic proportional valve 140. At this time, the engine 191 is stopped, and the pilot pump 136 is also stopped. Therefore, even if the electromagnetic proportional valve 140 is actuated, the directional control valve 130 does not operate.

[0097] When a predetermined time t0 has elapsed since the current application flag was set to open, the operation controller 150 causes the control current I supplied to the solenoid 146 of the electromagnetic proportional valve 140 to change from the maximum current Imax to the minimum current Imin. As a result, the valve core 142 of the electromagnetic proportional valve 140 moves from the fully open position to the fully closed position.

[0098] When the operator moves the ignition switch 188 from the ON position to the START position, the starter motor 196 is activated, and the engine controller 190 initiates the start-up control of the engine 191. Furthermore, during the crank start-up phase prior to engine 191 startup, the hydraulic excavator 100 is in the following state: Figure 5 The current application flag remains on because the current is applied in state No. 4.

[0099] It takes approximately several seconds from the moment the ignition switch 188 is operated to the start position until the engine 191 starts. In contrast, the application time (specified time) t0 of the drive current to the solenoid proportional valve 140 is approximately 200 to 300 msec. Therefore, even if the time from the ignition switch 188 to the start position is short, the valve core 142 of the solenoid proportional valve 140 can complete its full stroke when the operator operates the ignition switch 188 from the ACC position to the ON position.

[0100] When the engine 191 is started via crank starting and engine starting control based on engine controller 190, the state of the hydraulic excavator 100 changes from... Figure 5 The state of No.4 changes to state No.5, and the current application release condition is met. As a result, the current application flag is set to off.

[0101] When the operator determines that the engine 191 has finished starting, they return the ignition switch 188 from the start position to the on position. Furthermore, by removing their hand from the ignition switch 188, the switch returns to the on position via a spring (not shown) and remains there. Thus, the state of the hydraulic excavator 100 changes from... Figure 5 The state of No.5 changes to the state of No.6.

[0102] The operator operates the control device 180 to move the working device 104, the slewing body 103, and the traveling body 102 to perform digging, loading, and other operations. When the operator finishes work, they turn the ignition switch 188 to the off position. Since the ignition switch 188 is turned off via the ACC position, the operation controller 150 outputs an engine stop command to the engine controller 190. As a result, the engine 191 stops, and the hydraulic excavator 100 changes state from [previous state]. Figure 5The state of No.6 returns to the state of No.1 via the state of No.2.

[0103] According to the above implementation method, the following effects are obtained.

[0104] (1) The hydraulic excavator (operating machinery) 100 of this embodiment includes: an engine 191; a main pump (first pump) 135 and a pilot pump (second pump) 136 driven by the engine 191; a hydraulic actuator (hydraulic cylinder 110, etc.) driven by working oil supplied from the main pump 135; a directional control valve (control valve) 130 that controls the flow of working oil supplied from the main pump 135 to the hydraulic actuator (hydraulic cylinder 110, etc.); an electromagnetic proportional valve (solenoid valve) 140 that reduces the pressure of the working oil supplied from the pilot pump 136 to generate a pilot pressure for operating the directional control valve 130; a operation controller (control device) 150 that controls the electromagnetic proportional valve 140; an ignition switch (engine operation unit) 188 that can perform an operation to start the engine 191; and a speed sensor 192 that detects the speed of the engine 191.

[0105] The operation controller 150 determines whether the engine 191 is stopped based on the detection result of the speed sensor 192, and determines whether the current application condition is met. This current application condition includes turning on the ignition switch 188 without starting it via the ignition switch 188. If the operation controller 150 determines that the current application condition is met, it applies a drive current to the solenoid proportional valve 140 to drive the solenoid proportional valve 140.

[0106] According to this structure, when the engine 191 is stopped, the electromagnetic proportional valve 140 is actuated, thus preventing the hydraulic actuator (hydraulic cylinder 110, etc.) from operating due to the actuation of the electromagnetic proportional valve 140. Therefore, the movement of the valve core (valve body) 142 of the electromagnetic proportional valve 140 can be increased. That is, according to this embodiment, foreign objects inside the electromagnetic proportional valve 140 can be effectively removed without affecting the operation of the hydraulic actuator. As a result, malfunction of the hydraulic actuator caused by foreign objects stuck in the electromagnetic proportional valve 140 can be prevented.

[0107] (2) When the operation controller 150 determines that the current application condition is met and applies a drive current to the electromagnetic proportional valve 140, if it determines that the engine 191 is in an operating state, it stops applying the drive current to the electromagnetic proportional valve 140. According to this structure, even if the engine 191 starts, the application of the drive current to the electromagnetic proportional valve 140 during the fixation prevention control will be stopped. Therefore, malfunction of the hydraulic actuator caused by the fixation prevention control can be prevented.

[0108] (3) The electromagnetic proportional valve 140 has a valve core (valve body) 142 that generates a stroke between a fully closed position and a fully open position. When the operation controller 150 determines that the current application condition is met, it applies a drive current to the electromagnetic proportional valve 140 for a predetermined time t0, causing the valve core 142 to move to the full stroke position (fully open position) and holding the valve core 142 in the full stroke position. According to this structure, compared with the case where the valve core 142 is moved to a position such as an intermediate position between the fully closed and fully open positions by applying a drive current to the electromagnetic proportional valve 140, foreign objects can be removed more effectively.

[0109] As described above, according to this embodiment, a hydraulic excavator 100 can be provided that can more effectively remove foreign objects from the electromagnetic proportional valve 140 without affecting the operation of the hydraulic actuator.

[0110] <Modification 1 of the First Embodiment>

[0111] In the first embodiment, an example was described in which the operation controller 150 applies a drive current to the electromagnetic proportional valve 140 only once when the current application condition is determined to be met; however, the present invention is not limited thereto. The operation controller 150 may also apply a drive current to the electromagnetic proportional valve 140 repeatedly when the current application condition is determined to be met.

[0112] Figure 6B Is with Figure 6A The same diagram is a timing diagram of the control current supplied from the operation controller 150 of the first embodiment (Modified Example 1) to the solenoid 146 of the electromagnetic proportional valve 140. For example... Figure 6B As shown, when the current application flag is set from closed to open, the solenoid valve control unit 164 performs multiple cycles (three cycles in this modified example) of applying and stopping the drive current as one cycle of application processing. In one cycle of application processing, the solenoid valve control unit 164 outputs the maximum current Imax to the solenoid proportional valve 140 at a predetermined first time t1, and then outputs the minimum current Imin to the solenoid proportional valve 140 at a predetermined second time t2.

[0113] According to this modified example, foreign objects can be removed more effectively than when the electromagnetic proportional valve 140 is driven only once, thus reducing the frequency of the sticking phenomenon of the electromagnetic proportional valve 140.

[0114] <Modification 2 of the First Embodiment>

[0115] In the first embodiment, an example was described in which the operation controller 150 immediately outputs the maximum current Imax to the electromagnetic proportional valve 140 when it is determined that the current application condition is met; however, the present invention is not limited thereto. The operation controller 150 may also gradually increase the magnitude of the control current I over time when it is determined that the current application condition is met.

[0116] Figure 6C Is with Figure 6A The same diagram is a timing diagram of the control current supplied from the operation controller 150 of the first embodiment, variant 2, to the solenoid 146 of the electromagnetic proportional valve 140. For example... Figure 6C As shown, when the current application flag is set from closed to open, the solenoid valve control unit 164 gradually increases the control current I from the minimum current Imin to the maximum current Imax over time. According to this variation, depending on the state of the foreign matter present in the solenoid proportional valve 140, foreign matter can sometimes be removed more effectively than the control method described in the first embodiment.

[0117] <Modification 3 of the First Embodiment>

[0118] In the first embodiment, an example was described in which the current application condition determination unit 163 determines that the current application condition is met when both condition 1 and condition 2 are satisfied; however, the present invention is not limited to this. The current application condition at least includes the ignition switch 188 being turned on and the engine 191 being in a stopped state.

[0119] In this modified example, the current application condition is valid if all of the above conditions 1, 2 and 3 are satisfied, and is not valid if at least one of conditions 1, 2 and 3 is not satisfied.

[0120] (Condition 3) The operating device 180 is operated

[0121] Condition 3 is satisfied when the lever operation amount L of the operating device 180 is greater than or equal to the operation amount threshold L0.

[0122] The operation threshold L0 is a threshold used to determine whether the operating device 180 is operated, and it is pre-stored in the non-volatile memory 153 of the operation controller 150. When it is determined that the current application condition is met, the solenoid valve control unit 164 sets the current application flag to open.

[0123] In this variation, the operator moves the ignition switch 188 from the off position to the on position and operates the operating device 180, thereby driving the solenoid proportional valve 140. Therefore, even when the ignition switch 188 is moved from the off position to the on position, the solenoid proportional valve 140 can be avoided by not operating the operating device 180.

[0124] Furthermore, in this modified example, when the specified operating device 180 is operated, the operation controller 150 can drive all the electromagnetic proportional valves 140 corresponding to the plurality of hydraulic actuators, or it can drive only the electromagnetic proportional valves 140 corresponding to the operating direction of each operating device 180.

[0125] <Second Implementation>

[0126] Reference Figure 7 and Figure 8 The hydraulic excavator 100 of the second embodiment will be described. Furthermore, reference numerals will be used for structures that are the same as or equivalent to those described in the first embodiment; the main differences will be explained. In the second embodiment, the operation controller 250 applies a drive current corresponding to the operating amount of the operating device 180 to the electromagnetic proportional valve 140 when it is determined that the current application condition is met. The function of the operation controller 250 of the second embodiment will be described in detail below.

[0127] Figure 7 This is a functional block diagram of the operation controller 250 according to the second embodiment. For example... Figure 7 As shown, the operation controller 250 functions as the engine status determination unit 161, the switch operation determination unit 162, the current application condition determination unit 163, the solenoid valve control unit 264, the relay control unit 165, and the control current calculation unit 266 by executing the program stored in the non-volatile memory 153.

[0128] The control current calculation unit 266 converts the operation signal from the operation sensor 181 into a lever operation amount L. The lever operation amount L is represented, for example, by a value that is 0% when the lever is neutral and 100% when the lever is fully depressed (maximum operation). The control current calculation unit 266 refers to the control current characteristic Ic stored in the non-volatile memory 153 (refer to...). Figure 8 The target value It of the control current is calculated based on the lever operation amount L detected by the operation sensor 181. Figure 8 This is a diagram representing the control current characteristic Ic1. Figure 8 The control current characteristic Ic1 shown is stored in non-volatile memory 153 in tabular form.

[0129] The relationship between the lever operation amount L, determined by the control current characteristic Ic1, and the target value It of the control current is as follows: Within the range where the lever operation amount L is 0% to below the specified operation amount L1, the target value It of the control current is the minimum current Imin. Within the range where the lever operation amount L is greater than the specified operation amount L1 but less than the maximum operation amount, the target value It of the control current increases proportionally to the increase in the lever operation amount L until it reaches the specified current I0. When the lever operation amount L is the maximum operation amount, i.e., 100%, the target value It of the control current becomes the maximum current Imax.

[0130] Figure 7 When the current application flag is set from closed to open, the solenoid valve control unit 264 applies a control current I calculated by the control current calculation unit 266 to the solenoid proportional valve 140.

[0131] In addition, the current application condition determination unit 163 is the same as in the first embodiment. When the engine state determination unit 161 determines that the engine 191 is in a stopped state and the switch operation determination unit 162 determines that the ignition switch 188 is operated to the on position, the current application condition is determined to be met.

[0132] In this second embodiment, the operator moves the ignition switch 188 from the off position to the on position and operates the operating device 180, thereby actuating the electromagnetic proportional valve 140. The valve core 142 of the electromagnetic proportional valve 140 actuates according to the amount of operation of the operating device 180. Therefore, for example, if the operator repeatedly moves the operating lever 182 of the operating device 180 from the neutral position to the maximum operating amount and then repeatedly returns it to the neutral position, the valve core 142 of the electromagnetic proportional valve 140 reciprocates between the fully closed position and the fully open position. Furthermore, when the operator gradually tilts the operating lever 182 of the operating device 180 from the neutral position to the maximum operating amount, the valve core 142 of the electromagnetic proportional valve 140 gradually moves from the fully closed position to the fully open position.

[0133] Thus, when the operation controller 250 of this second embodiment determines that the current application condition is met, it applies a drive current corresponding to the operation amount of the operating device 180 to the electromagnetic proportional valve 140. Therefore, according to this second embodiment, the valve core 142 of the electromagnetic proportional valve 140 can be actuated according to the operation of the operating device 180. Since the valve core 142 of the electromagnetic proportional valve 140 can perform various operations, foreign matter can be removed more efficiently.

[0134] Furthermore, in this second embodiment, when the specified operating device 180 is operated, the operation controller 250 can drive all the electromagnetic proportional valves 140 corresponding to the plurality of hydraulic actuators, or it can drive only the electromagnetic proportional valves 140 corresponding to the operating direction of each operating device 180.

[0135] <Third Implementation Method>

[0136] Reference Figure 9 and Figure 10 The hydraulic excavator 100 of the third embodiment will be described. Furthermore, reference numerals will be used for structures that are the same as or equivalent to those described in the first embodiment, and the main differences will be explained. The lower the temperature of the working oil detected by the temperature sensor 189, the greater the drive current applied to the solenoid proportional valve 140 by the operation controller 350 of the third embodiment. The function of the operation controller 350 of the third embodiment will be described in detail below.

[0137] Figure 9 This is a functional block diagram of the operation controller 350 according to the third embodiment. For example... Figure 9 As shown, the operation controller 350 functions as the engine status determination unit 161, the switch operation determination unit 162, the current application condition determination unit 163, the solenoid valve control unit 364, the relay control unit 165, and the control current calculation unit 366 by executing the program stored in the non-volatile memory 153.

[0138] The control current calculation unit 366 refers to the control current characteristic Ic2 (reference) stored in the non-volatile memory 153. Figure 10 The target value It of the control current is calculated based on the temperature T of the working oil detected by the temperature sensor 189. Figure 10 This is a diagram representing the control current characteristic Ic2. Figure 10 The control current characteristic Ic2 shown is stored in non-volatile memory 153 in tabular form.

[0139] The relationship between the working oil temperature T and the target value It of the control current, determined by the control current characteristic Ic2, is as follows: When the working oil temperature T is below the first temperature T1, the target value It of the control current is the first current I1. When the working oil temperature T is greater than the first temperature T1 but less than the second temperature T2, the target value It of the control current decreases proportionally with the increase of the working oil temperature T. When the working oil temperature T is above the second temperature T2, the target value It of the control current becomes the second current I2.

[0140] The first temperature T1 and the second temperature T2 are related in the order T1 < T2, and the first current I1 and the second current I2 are related in the order I1 > I2. The first temperature T1 is, for example, approximately -20°C, and the second temperature T2 is, for example, approximately 20°C. The first current I1 is the current value that enables the valve core 142 to move to its full stroke position when the working oil temperature T is the first temperature T1 and a driving current is applied for a specified time t0. The second current I2 is the current value that enables the valve core 142 to move to its full stroke position when the working oil temperature T is the second temperature T2 and a driving current is applied for a specified time t0.

[0141] Figure 9 When the current application flag is set from closed to open, the solenoid valve control unit 364 applies a control current I calculated by the control current calculation unit 366 to the solenoid proportional valve 140 for a specified time t0.

[0142] The lower the temperature T of the working oil, the higher its viscosity. When the working oil viscosity is high, the force required to drive the valve core 142 is greater compared to when the working oil viscosity is low. Therefore, the lower the working oil temperature T detected by the temperature sensor 189, the greater the drive current applied to the electromagnetic proportional valve 140 by the operation controller 350 of this third embodiment. As a result, even in winter when the working oil temperature T is low, the electromagnetic proportional valve 140 can be moved from the fully closed position to the fully open position. In addition, in summer when the working oil temperature T is high, by reducing the drive current supplied to the electromagnetic proportional valve 140, the decrease in the charging rate of the battery 197 can be suppressed.

[0143] <Fourth Implementation>

[0144] Reference Figure 11 and Figure 12 The hydraulic excavator 100 of the fourth embodiment will be described. Furthermore, reference numerals will be used for structures that are the same as or equivalent to those described in the first embodiment, and the main differences will be explained. The lower the temperature of the working oil detected by the temperature sensor 189, the longer the operation controller 450 of the fourth embodiment applies drive current to the solenoid proportional valve 140. The function of the operation controller 450 of the fourth embodiment will be described in detail below.

[0145] Figure 11 This is a functional block diagram of the operation controller 450 according to the fourth embodiment. For example... Figure 11 As shown, the operation controller 450 functions as the engine state determination unit 161, the switch operation determination unit 162, the current application condition determination unit 163, the solenoid valve control unit 464, the relay control unit 165, and the application time calculation unit 467 by executing the program stored in the non-volatile memory 153.

[0146] The application timing calculation unit 467 refers to the application timing characteristic tc (reference) stored in the non-volatile memory 153. Figure 12 The application time ta is calculated based on the working oil temperature T detected by the temperature sensor 189. Figure 12 This is a graph representing the applied time characteristic tc. Figure 12 The application time characteristic tc shown is stored in non-volatile memory 153 in tabular form.

[0147] The relationship between the working oil temperature T and the application time ta, determined by the application time characteristic tc, is as follows: When the working oil temperature T is below the first temperature T1, the application time ta is the first time t1. When the working oil temperature T is greater than the first temperature T1 but less than the second temperature T2, the application time ta decreases proportionally to the increase in the working oil temperature T. When the working oil temperature T is above the second temperature T2, the application time ta is the second time t2.

[0148] The relationship between the first temperature T1 and the second temperature T2 is T1 < T2, and the relationship between the first time t1 and the second time t2 is t1 > t2. The first temperature T1 is, for example, approximately -20℃, and the second temperature T2 is, for example, approximately 20℃. The first time t1 is the application time required to move the valve core 142 to its full stroke position when the working oil temperature T is the first temperature T1 and the maximum current Imax is applied to the electromagnetic proportional valve 140. The second time t2 is the application time required to move the valve core 142 to its full stroke position when the working oil temperature T is the second temperature T2 and the maximum current Imax is applied to the electromagnetic proportional valve 140.

[0149] Figure 11 When the current application flag is set from closed to open, the solenoid valve control unit 464 applies a maximum current Imax to the solenoid proportional valve 140 during the application time ta calculated by the application time calculation unit 467.

[0150] As explained in the third embodiment, the lower the temperature T of the working oil, the higher its viscosity. When the working oil viscosity is high, the force required to drive the valve core 142 increases compared to when the working oil viscosity is low. Therefore, the lower the working oil temperature T detected by the temperature sensor 189, the longer the operation controller 450 of this fourth embodiment applies the drive current to the electromagnetic proportional valve 140. As a result, even in winter when the working oil temperature T is low, the electromagnetic proportional valve 140 can be moved from the fully closed position to the fully open position. Furthermore, in summer when the working oil temperature T is high, by reducing the application time of the drive current to the electromagnetic proportional valve 140, the decrease in the charging rate of the battery 197 can be suppressed.

[0151] <Fifth Implementation>

[0152] Reference Figure 13 The hydraulic excavator 100 of the fifth embodiment will be described. Furthermore, reference numerals will be used for structures that are the same as or equivalent to those described in the first embodiment, and the main differences will be explained. The operation controller 550 of the fifth embodiment monitors whether the electromagnetic proportional valve 140 has experienced any abnormalities such as open circuits or short circuits, and notifies the operator of any such abnormalities. The functions of the operation controller 550 of the fifth embodiment will be described in detail below.

[0153] Figure 13 This is a functional block diagram of the operation controller 550 according to the fifth embodiment. Figure 13 As shown, the operation controller 550 functions as the engine status determination unit 161, the switch operation determination unit 162, the current application condition determination unit 163, the solenoid valve control unit 164, the relay control unit 165, the solenoid valve monitoring unit 568, and the display control unit 569 by executing the program stored in the non-volatile memory 153.

[0154] The solenoid valve monitoring unit 568 monitors the feedback current from the solenoid proportional valve 140. If the feedback value of the control current of the solenoid proportional valve 140 is less than a first current threshold, the solenoid valve monitoring unit 568 determines that a low current anomaly has occurred. If the feedback value of the control current of the solenoid proportional valve 140 is greater than or equal to a second current threshold, the solenoid valve monitoring unit 568 determines that the operation is normal.

[0155] The first current threshold is a threshold used to determine whether a low current anomaly has occurred, and it is pre-stored in the non-volatile memory 153 of the operation controller 150. The second current threshold is a threshold used to determine whether a high current anomaly has occurred, and it is pre-stored in the non-volatile memory 153 of the operation controller 150.

[0156] When the solenoid valve monitoring unit 568 determines that a high current abnormality has occurred, the display control unit 569 generates a first image, such as an icon or message, indicating that the high current abnormality has caused the sticking prevention control of the solenoid proportional valve 140 to malfunction, and outputs it to the display device 115. The display device 115 displays the first image on the display screen and notifies the operator that a high current abnormality has caused the sticking prevention control of the solenoid proportional valve 140 to malfunction.

[0157] When the solenoid valve monitoring unit 568 determines that a low current abnormality has occurred, the display control unit 569 generates a second image, such as an icon or message, indicating that the low current abnormality has caused the sticking prevention control of the solenoid proportional valve 140 to malfunction, and outputs it to the display device 115. The display device 115 displays the second image on the display screen and notifies the operator that a low current abnormality has caused the sticking prevention control of the solenoid proportional valve 140 to malfunction.

[0158] In the hydraulic excavator 100, if the engine 191 has not been started for a long time, sometimes due to the rupture of the oil film in the valve core 142 of the electromagnetic proportional valve 140 or the deterioration of the working oil, a solidification phenomenon may occur when the engine 191 is started. In this case, if the feedback value of the control current exceeds the second threshold, the electromagnetic valve monitoring unit 568 determines that a high current abnormality has occurred.

[0159] Thus, the operation controller 550 of this fifth embodiment determines whether the electromagnetic proportional valve 140 has malfunctioned. If an malfunction occurs, it controls the display device 115 to display an image indicating that the malfunction has caused the seizing prevention control to fail. This allows the operator to recognize malfunctions such as broken wires or short circuits in the wires guiding current to the electromagnetic proportional valve 140, or seizing caused by oil film rupture or deterioration of the working oil, which cause the seizing prevention control to fail. Therefore, the operator can take appropriate measures such as inspection and repair to eliminate the malfunction. Thus, malfunctions of the hydraulic actuator caused by seizing of the electromagnetic proportional valve 140 can be prevented.

[0160] <Modifications of the Fifth Embodiment>

[0161] In the fifth embodiment, the display device 115 was described as an example of functioning as a notification device to inform the operator of malfunctions in the electromagnetic proportional valve 140, but the present invention is not limited thereto. The notification device may also be a sound output device such as a speaker that informs the operator of malfunctions by sound. The notification device may also be a light-emitting device having a light-emitting element such as an LED that informs the operator of malfunctions by lighting up or flashing.

[0162] The following variations are also within the scope of the present invention. It is also possible to combine the structures shown in the variations with the structures described in the above embodiments, or to combine the structures described in the different embodiments above with each other, or to combine the structures described in the different variations below with each other.

[0163] <Variation Example 1>

[0164] In the above embodiment, an example of an engine key switch serving as the engine control unit ignition switch 188 was described, but the present invention is not limited to this. The ignition switch 188 may also be a push-button type switch. The push-button type ignition switch 188 switches its operating state based on the duration and number of presses. For example, when the ignition switch 188 is in the off operating state, if the ignition switch 188 is pressed down (e.g., for more than 500 ms), the ACC relay 194, IG relay 195, and starter relay 193 are activated, and the engine 191 starts. The switch operation determination unit 162 determines that an activation operation has been performed when the ignition switch 188 is pressed. That is, the switch operation determination unit 162 determines that an operation to start the engine 191 has been performed via the ignition switch 188.

[0165] Furthermore, when the ignition switch 188 is in the off operating state, if the ignition switch 188 is pressed briefly (for example, less than 500ms), the ACC relay 194 is activated, thus entering the ACC on state. When the ACC is on, if the ignition switch 188 is pressed briefly, the IG relay 195 is activated, thus entering the IG on state. When the IG is on, if the ignition switch 188 is pressed briefly, both the ACC relay 194 and the IG relay 195 are deactivated. If the ignition switch 188 is pressed while the ACC is on, the switch operation determination unit 162 determines that an on operation has been performed.

[0166] <Variation Example 2>

[0167] In the above embodiment, an example of seizure prevention control performed by the operation controller 150 has been described, but the present invention is not limited thereto. The body control controller 120 and the engine controller 190 may also have a portion of the functions of the operation controller 150. For example, the engine controller 190 determines whether the engine 191 is in a stopped state or an operating state based on the detection result of the speed sensor 192, and outputs the determination result to the body control controller 120. When the body control controller 120 is powered on and performs initial settings, it determines that the ignition switch 188 has been turned on. If it receives a determination result from the engine controller 190 indicating that the engine 191 is in a stopped state, it determines that the current application condition is met. When the body control controller 120 determines that the current application condition is met, it applies a drive current to the electromagnetic proportional valve 140. In this way, seizure prevention control can also be performed by multiple controllers (control devices) 120, 190 working together.

[0168] <Variation Example 3>

[0169] In the above embodiment, the speed threshold N1 is achievable by the engine control dial 198 (refer to...). Figure 2The example described is a value set below the minimum speed setting, which is greater than the maximum crank starting speed of the starter motor 196. However, the present invention is not limited to this. The speed threshold N1 can also be set to the same value as the speed threshold N0. In this case, when crank starting begins, the application of drive current to the electromagnetic proportional valve 140 is stopped, thus reliably preventing the effect of the seizure prevention control on the vehicle body behavior.

[0170] <Variation Example 4>

[0171] In the above embodiments, an example of a structure in which the electromagnetic proportional valve 140 is always closed (normally closed) has been described, but the present invention is not limited thereto. The present invention can also be applied when the electromagnetic proportional valve 140 is always open (normally open).

[0172] <Variation Example 5>

[0173] In the above embodiments, an example of an electromagnetic proportional valve (solenoid valve) 140 having a valve core 142 as its valve body has been described, but the present invention is not limited thereto. The present invention can also be applied to solenoid valves having a lift valve as its valve body.

[0174] <Variation Example 6>

[0175] In the above embodiment, an example of starting control of engine 191 during a start-up operation based on ignition switch 188 has been described. However, it is also possible to start control of engine 191 only if an engine starting prerequisite is met during a start-up operation based on ignition switch 188. For example, the engine starting prerequisite is met when the door lock lever device 185 is operated to the locked position.

[0176] <Variation Example 7>

[0177] In the above embodiment, an example of an electrical operating device 180 that generates a command pilot pressure by controlling the electromagnetic proportional valve 140 based on the control current from the controllers 120 and 150 has been described, but the present invention is not limited thereto. The present invention can also be applied to hydraulically piloted operating devices. A hydraulically piloted operating device includes a pressure reducing valve, which is directly driven by an operating lever to output a pilot operating pressure corresponding to the operating amount to a directional control valve 130. Sometimes, an electromagnetic proportional valve capable of further reducing the pilot operating pressure is provided between the pressure reducing valve and the directional control valve 130 of the operating device. Additionally, sometimes an electromagnetic proportional valve is provided via a high-pressure selector valve on the pilot line guiding the pilot operating pressure generated by the pressure reducing valve of the operating device. In this configuration, the higher of the command pilot pressure generated by the electromagnetic proportional valve and the pilot operating pressure generated by the pressure reducing valve of the operating device is guided to the directional control valve 130. In these configurations, sticking prevention control of the electromagnetic proportional valve can also prevent sticking.

[0178] <Variation Example 8>

[0179] In the above embodiment, an example of the body control controller 120 driving the electromagnetic proportional valve 140 according to the operation amount of the operator's operating device 180 has been described, but the present invention is not limited thereto. The present invention can also be applied to the fixation prevention control of the electromagnetic proportional valve 140 used in autonomous driving control. In this case, for example, the body control controller 120 drives the electromagnetic proportional valve 140 according to a predetermined action plan.

[0180] <Variation Example 9>

[0181] In the above embodiment, an example of the operation controller 150 controlling the on / off switching of various relays 193, 194, and 195 according to the operating position of the ignition switch 188 has been described, but the present invention is not limited thereto. Various relays 193, 194, and 195 may also be configured to mechanically open and close according to the rotation operation of the ignition switch 188.

[0182] <Variation Example 10>

[0183] In the above embodiments, the example described is a tracked hydraulic excavator 100, but the present invention is not limited thereto. The present invention can be applied to various types of working machinery such as wheeled hydraulic excavators, wheeled loaders, road machinery, cranes, and dump trucks.

[0184] The embodiments of the present invention have been described above, but the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific structure of the above embodiments.

[0185] Symbol Explanation

[0186] 100…Hydraulic excavator (operating machinery), 102…Travel body, 102A…Travel motor (hydraulic actuator), 103…Swing body, 103A…Swing motor (hydraulic actuator), 104…Working device, 105…Body, 107…Tank, 110…Hydraulic cylinder (hydraulic actuator), 111…Boom, 111A…Boom cylinder (hydraulic actuator), 112…Stick, 112A…Stick cylinder (hydraulic actuator), 113…Bucket, 113A… Bucket cylinder (hydraulic actuator), 115…display device (notification device), 120…body control controller (control device), 130…direction control valve (control valve), 135…main pump (first pump), 136…pilot pump (second pump), 140…electromagnetic proportional valve (solenoid valve), 142…valve core (valve body), 150…operation controller (control device), 161…engine status determination unit, 162…switch operation determination unit, 163…current application condition Judgment Unit, 164…Solenoid Valve Control Unit, 165…Relay Control Unit, 180…Operating Device, 181…Operating Sensor, 182…Operating Lever (Operating Component), 188…Ignition Switch (Engine Operating Unit), 189…Temperature Sensor, 190…Engine Controller (Control Device), 191…Engine, 192…Speed ​​Sensor, 193…Starter Relay, 194…ACC Relay, 195…IG Relay, 196…Starter Motor, 197…Battery, 250…Operation Controller (Control Device), 264…Solenoid Valve Control Unit, 266…Control Current Calculation Unit, 350…Operation Controller (Control Device), 364…Solenoid Valve Control Unit, 366…Control Current Calculation Unit, 450…Operation Controller (Control Device), 464…Solenoid Valve Control Unit, 467…Application Time Calculation Unit, 550…Operation Controller (Control Device), 568…Solenoid Valve Monitoring Unit, 569…Display Control Unit.

Claims

1. A work machine having: an engine; a first pump and a second pump driven by the engine; a hydraulic actuator driven by working oil supplied from the first pump; an operation device for operating the hydraulic actuator; a control valve that controls a flow of working oil supplied from the first pump to the hydraulic actuator; a solenoid valve that is driven in accordance with an operation of the operation device, depressurizes a pressure of working oil supplied from the second pump, and generates a pilot pressure for operating the control valve; a control device that controls the solenoid valve; an engine operation portion via which a starting operation of the engine is possible by an on operation; and a rotation speed sensor that detects a rotation speed of the engine, characterized in that the control device determines whether or not a current application condition is satisfied, the current application condition including a determination that the engine is in a stopped state based on a detection result of the rotation speed sensor, and that an operation amount of the operation device is a threshold value or more in a state in which the on operation is performed to the engine operation portion and the operation device is operated, the control device drives the solenoid valve by applying a drive current corresponding to the operation amount of the operation device to the solenoid valve in a case where it is determined that the current application condition is satisfied.

2. The work machine according to claim 1, characterized in that the control device stops the application of the drive current to the solenoid valve if it is determined that the engine is in an operating state in a state where it is determined that the current application condition is satisfied and the drive current is applied to the solenoid valve.

3. The work machine according to claim 1, characterized in that the solenoid valve has a valve body that makes a stroke between a fully closed position and a fully open position, the control device applies the drive current to the solenoid valve to move the valve body to a position of full stroke and to hold the valve body at the position of full stroke for a predetermined prescribed time in a case where it is determined that the current application condition is satisfied.

4. The work machine according to claim 1, characterized in that the control device repeatedly applies the drive current to the solenoid valve a plurality of times in a case where it is determined that the current application condition is satisfied.

5. The work machine according to claim 1, characterized in that the work machine has a temperature sensor that detects a temperature of working oil supplied to the solenoid valve, the control device applies a larger drive current to the solenoid valve or a longer time of applying the drive current to the solenoid valve as the temperature of the working oil detected by the temperature sensor is lower.

6. The work machine according to claim 1, characterized in that the control device applies the drive current to the solenoid valve to drive the solenoid valve based on a predetermined relationship between the drive current and the time regardless of the operation amount of the operation device in a case where it is determined that the current application condition is satisfied. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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