Work machine

Abstract

A control system of the present invention comprises a hydraulic component that controls hydraulic oil by means of a movable adjustment member, and a controller that controls the hydraulic component. The controller performs an adjustment process for improving the control accuracy of the hydraulic component by driving the adjustment member.

Description

Work machine

[0001] This disclosure relates to a work machine. This application claims priority to Japanese Patent Application No. 2024-168905, filed in Japan on September 27, 2024, the content of which is incorporated herein by reference.

[0002] The work machine includes hydraulic components such as a hydraulic motor and a valve. Precise control of these hydraulic components is required.

[0003] International Publication No. 2015 / 137524

[0004] An object of this disclosure is to provide a work machine capable of improving the control accuracy of hydraulic components.

[0005] According to one aspect of the present invention, a work machine includes a hydraulic component that controls hydraulic oil by a movable adjustment member, and a controller that controls the hydraulic component, and the controller performs an adjustment process of driving the adjustment member to improve the control accuracy of the hydraulic component.

[0006] According to the above aspect, the work machine can improve the control accuracy of the hydraulic component.

[0007] It is a perspective view showing the configuration of a work machine according to the first embodiment. It is a schematic block diagram showing the configuration of a drive system according to the first embodiment. It is a cross-sectional view showing the schematic configuration of a flow control valve according to the first embodiment. It is a schematic block diagram showing the configuration of a control device according to the first embodiment. It is a diagram showing an example of an instruction screen according to the first embodiment. In the first embodiment, it is a diagram showing an example of a command signal transmitted to one hydraulic component during air bleeding processing. It is a diagram showing a time chart (part 1) of a command signal according to the first embodiment. It is a diagram showing a time chart (part 2) of a command signal according to the first embodiment. It is a schematic block diagram showing the configuration of a computer according to at least one embodiment.

[0008] 〈First Embodiment〉 《Configuration of Work Machine》 Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing the configuration of a work machine 1 according to the first embodiment. The work machine 1 according to the first embodiment is a hydraulic excavator.

[0009] Figure 1 is a perspective view of a work machine 1 according to the first embodiment. The work machine 1 according to the first embodiment is, for example, a hydraulic excavator. The work machine 1 comprises a traveling body 110, a rotating body 120, a work machine 130, a driver's cab 140, and a machine room 150. The work machine 1, being a hydraulic excavator, excavates and levels soil and other materials at a work site. The traveling body 110 and the rotating body 120 constitute the vehicle body.

[0010] The vehicle body 110 supports the work machine 1 so that it can move. The vehicle body 110 has a pair of left and right tracks 111. The work machine 1 moves forward, turns, or moves backward by the rotation of the pair of tracks 111. Hereinafter, the drive motor 112 for driving the right track 111 will be called the first drive motor 112R, and the drive motor 112 for driving the left track 111 will be called the second drive motor 112L.

[0011] The slewing body 120 is supported by the traveling body 110 so that it can rotate. The slewing body 120 rotates relative to the traveling body 110 by a slewing motor 127. The slewing body 120 is also equipped with a slewing brake, which is a mechanical brake that applies braking force to the slewing motor 127 to mechanically stop and hold the slewing body 120. The slewing brake is an example of a restraining device that restrains the actuator from moving. The slewing body 120 supports the work machine 130, the operator's cab 140, and the machine room 150.

[0012] The work machine 130 is movably supported on the body (slewing body 120) of the work machine 1. The work machine 130 comprises a boom 131, an arm 132, and a bucket 133 which is a work tool. The base end of the boom 131 is rotatably attached to the slewing body 120. The base end of the arm 132 is rotatably attached to the tip of the boom 131. The bucket 133 is rotatably attached to the tip of the arm 132.

[0013] The work machine 130 is driven by a plurality of actuators. The plurality of actuators include, for example, a boom cylinder 131C, an arm cylinder 132C, and a bucket cylinder 133C.

[0014] The boom cylinder 131C is a hydraulic cylinder for driving the boom 131. The base end of the boom cylinder 131C is attached to the slewing body 120. The tip end of the boom cylinder 131C is attached to the boom 131. The arm cylinder 132C is a hydraulic cylinder for driving the arm 132. The base end of the arm cylinder 132C is attached to the boom 131. The tip end of the arm cylinder 132C is attached to the arm 132. The bucket cylinder 133C is a hydraulic cylinder for driving the bucket 133. The base end of the bucket cylinder 133C is attached to the arm 132. The tip end of the bucket cylinder 133C is attached to the bucket 133.

[0015] The operator's cab 140 is where the operator of the work machine 1 sits and operates and controls it. The operator's cab 140 is located, for example, on the left side of the front end of the slewing body 120. The operator's cab 140 of the work machine 1 is equipped with a driver's seat 141 for the operator to sit in, an operating device 142 for operating the work machine 1, a control device 145 for controlling the work machine 1, and a monitor 146 which is the interface of the control device 145. The operating device 142 is operated by the operator to operate the work machine 1. The operating device 142 outputs an operation signal in response to the operator's operation.

[0016] The control device 145 controls the work machine 1. The control device 145 receives operation signals from the operating device 142. Based on the operation signals from the operating device 142, the control device 145 controls the movement of the traveling body 110, the driving of the work machine 130, and the rotational movement of the rotating body 120.

[0017] The machine room 150 houses the drive system 20, which will be described later. The machine room 150 is located, for example, behind the driver's cab 140. The machine room 150 forms a space for housing the drive system 20.

[0018] 《Configuration of the drive system 20》 Figure 2 is a schematic block diagram showing the configuration of the drive system 20 according to the first embodiment. The drive system 20 includes an engine 121, a front hydraulic pump 122A, a rear hydraulic pump 122B, a front main oil passage 123A, a rear main oil passage 123B, a main connecting oil passage 124, a front control valve 126A, a rear control valve 126B, a swing motor 127, a boom cylinder 131C, an arm cylinder 132C, a bucket cylinder 133C, a first travel motor 112R, and a second travel motor 112L. Hereinafter, the front hydraulic pump 122A and the rear hydraulic pump 122B will be collectively referred to as the hydraulic pump 122. Also, hereafter, the front main oil passage 123A and the rear main oil passage 123B will be collectively referred to as the main oil passage 123. Also, hereafter, the front control valve 126A and the rear control valve 126B will be collectively referred to as the control valve 126.

[0019] The engine 121 is a prime mover that drives the hydraulic pump 122. In the first embodiment, the engine 121 is a diesel engine. Examples of engines 121 in other embodiments may include a gasoline engine or an electric motor. The front hydraulic pump 122A and the rear hydraulic pump 122B are variable displacement pumps driven by the engine 121. The front hydraulic pump 122A supplies hydraulic fluid to the front main oil passage 123A. The rear hydraulic pump 122B supplies hydraulic fluid to the rear main oil passage 123B. The front hydraulic pump 122A is provided with a front swash plate angle sensor 1221A that measures the inclination angle of the swash plate of the front hydraulic pump 122A. The rear hydraulic pump 122B is provided with a rear swash plate angle sensor 1221B that measures the inclination angle of the swash plate of the rear hydraulic pump 122B. Since the capacity of the hydraulic pump 122 is determined by the inclination angle of the swash plate, the control device 145 can determine the discharge amount of the hydraulic pump 122 based on the measurement value of the swash plate angle sensor 1221. The hydraulic pump 122 includes a cylinder block (not shown) with one end fixed to the bottom surface of the pump and the other end pivotably supported by the swash plate. The cylinder block is operated by hydraulic fluid. The angle of the swash plate of the hydraulic pump 122 changes with the expansion and contraction of the cylinder block. Note that the discharge amount of the hydraulic pump 122 also changes with rotational speed in addition to capacity, so if the work machine 1 according to another embodiment controls the discharge amount of the hydraulic pump 122 by rotational speed, the work machine 1 may be equipped with a sensor that measures the rotational speed of the hydraulic pump 122 instead of the swash plate angle sensor 1221.

[0020] The main oil passage 123 is equipped with a pump discharge pressure sensor 1231 and a bleed valve 1232. The pump discharge pressure sensor 1231 measures the pressure of the hydraulic fluid discharged by the hydraulic pump 122. The bleed valve 1232 discharges the hydraulic fluid supplied when the actuator is not being driven. The bleed valve 1232 has a spool that adjusts the opening area. The position of the spool is controlled by the hydraulic fluid. Even when the actuator is not being driven, the hydraulic pump 122 discharges a minimum flow rate of hydraulic fluid. Hereinafter, the pump discharge pressure sensor 1231 provided in the front main oil passage 123A will also be referred to as the front pump discharge pressure sensor 1231A, and the pump discharge pressure sensor 1231 provided in the rear main oil passage 123B will also be referred to as the rear pump discharge pressure sensor 1231B. Furthermore, the bleed valve 1232 provided in the front main oil passage 123A is also called the front bleed valve 1232A, and the bleed valve 1232 provided in the rear main oil passage 123B is also called the rear bleed valve 1232B.

[0021] The main connecting oil passage 124 connects the front main oil passage 123A and the rear main oil passage 123B. The main connecting oil passage 124 is equipped with a main confluence / separation valve 1241. The main confluence / separation valve 1241 is a shut-off valve that controls the opening and closing of the main connecting oil passage 124. This allows the main confluence / separation valve 1241 to switch between confluence or separation of the hydraulic fluid flowing through the front main oil passage 123A and the hydraulic fluid flowing through the rear main oil passage 123B.

[0022] The front control valve 126A is connected to the front main oil passage 123A. The front control valve 126A distributes the hydraulic fluid supplied from the front main oil passage 123A to the swing motor 127, the arm cylinder 132C, and the first travel motor 112R. Hereinafter, the set of the swing motor 127, arm cylinder 132C, and first travel motor 112R connected to the front control valve 126A will also be referred to as the front actuator unit UA. The swing motor 127 is equipped with a swing load pressure sensor 127P that measures the pressure (load pressure) on the inlet side of the swing motor 127. The arm cylinder 132C is equipped with an arm load pressure sensor 132CP that measures the pressure (load pressure) on the inlet side of the arm cylinder 132C. The first travel motor 112R is equipped with a front travel load pressure sensor 112RP that measures the pressure (load pressure) on the inlet side of the first travel motor 112R.

[0023] The rear control valve 126B is connected to the rear main oil passage 123B. The rear control valve 126B distributes the hydraulic fluid supplied from the rear main oil passage 123B to the boom cylinder 131C, the bucket cylinder 133C, and the second travel motor 112L. Hereinafter, the set of boom cylinder 131C, bucket cylinder 133C, and second travel motor 112L connected to the rear control valve 126B will also be referred to as the rear actuator unit UB. The boom cylinder 131C is equipped with a boom load pressure sensor 131CP that measures the pressure (load pressure) on the inlet side of the boom cylinder 131C. The bucket cylinder 133C is equipped with a bucket load pressure sensor 133CP that measures the pressure (load pressure) on the inlet side of the bucket cylinder 133C. The second travel motor 112L is equipped with a rear travel load pressure sensor 112LP that measures the pressure (load pressure) on the inlet side of the second travel motor 112L. The front control valve 126A or the rear control valve 126B may be provided with a port for supplying hydraulic fluid to actuators (such as breakers, grapples, and tilt rotators) installed on the work tool (attachment).

[0024] The control valve 126 has a flow control valve 1261 and a pressure compensation valve 1262 for each actuator. The flow control valve 1261 adjusts the flow rate of hydraulic fluid supplied to the corresponding actuator in accordance with a command from the control device 145. The flow control valve 1261 has a spool that adjusts the opening area. The position of the spool is controlled by the hydraulic fluid. The pressure compensation valve 1262 compensates for the flow distribution to each actuator even if the load pressure of each actuator provided in the same control valve 126 (main oil passage 123) is different, preventing the hydraulic fluid from being unevenly distributed to the actuator on the low-load side. The pressure compensation valve 1262 applies a pressure loss to the low-load shaft so that the outlet pressure of the flow control valve 1261 of the low-load actuator becomes equal to the outlet pressure of the flow control valve 1261 of the actuator with the maximum load pressure. As a result, the outlet pressure of each main operating valve 60 becomes equal, and flow distribution using the meter-in opening area ratio can be realized. Therefore, the same control valve 126 is provided with an LS (load sensing) oil passage 128 that shares the hydraulic fluid at the outlet of each flow control valve 1261. Each pressure compensation valve 1262 is connected to the LS oil passage 128. This allows the pressure compensation valve 1262 to detect the maximum load pressure.

[0025] Although not shown in Figure 2, each actuator is provided with four flow control valves 1261. The first flow control valve 1261 is a valve through which hydraulic fluid flows in to the first side of the actuator (for example, the head side of the power cylinder or the left-hand rotation side of the hydraulic motor). The second flow control valve 1261 is a valve through which hydraulic fluid flows out from the first side of the actuator. The third flow control valve 1261 is a valve through which hydraulic fluid flows in to the second side of the actuator (for example, the bottom side of the power cylinder or the right-hand rotation side of the hydraulic motor). The fourth flow control valve 1261 is a valve through which hydraulic fluid flows out from the second side of the actuator. In other embodiments, the flow control valves 1261 may be provided only on either the inflow side or the outflow side. Hereinafter, the LS oil passage 128 of the front control valve 126A will be referred to as the front LS oil passage 128A, and the LS oil passage 128 of the rear control valve 126B will be referred to as the rear LS oil passage 128B.

[0026] The LS connecting oil passage 129 connects the front LS oil passage 128A and the rear LS oil passage 128B. The LS connecting oil passage 129 is provided with an LS confluence / separation valve 1291. The LS confluence / separation valve 1291 is a shut-off valve that controls the opening and closing of the LS connecting oil passage 129. This allows the LS confluence / separation valve 1291 to switch between confluence or separation of the hydraulic fluid flowing through the front LS oil passage 128A and the hydraulic fluid flowing through the rear LS oil passage 128B. When the front LS oil passage 128A and the rear LS oil passage 128B confluence, the maximum load pressure of the actuators connected to the front control valve 126A and the actuator connected to the rear control valve 126B is applied to each pressure compensation valve 1262.

[0027] 《Air Vent Structure for Hydraulic Components》 Figure 3 is a cross-sectional view showing the schematic configuration of a flow control valve 1261 according to the first embodiment. The flow control valve 1261 comprises a valve body 31, a spool 32 (valve body), a spring 33 (elastic body), and a stroke sensor 34. The valve body 31 forms the outer shell of the flow control valve 1261. Inside the valve body 31, a sliding space 311 is formed in which the spool 32 can slide in one direction. Hereinafter, the wall surface at one end of the spool 32 in the sliding direction of the valve body 31 will be called the first end surface, the wall surface at the other end in the sliding direction will be called the second end surface, and the other wall surfaces will be called side surfaces. The sliding space 311 is provided with a first stopper 316 that defines the stroke end on the first end surface side of the spool 32, and a second stopper 317 that defines the stroke end on the second end surface side of the spool 32. The first stopper 316 and the second stopper 317 are projections that protrude inward into the sliding space 311, and they stop the spool 32 by coming into contact with it.

[0028] The spool 32 is slidably mounted within the sliding space 311. The spool 32 is provided with a groove for adjusting the flow rate of the hydraulic fluid. The spring 33 is connected to the first end face of the sliding space 311 and to the spool 32. In other words, the spring 33 biases the spool 32 from the first end to the second end. The stroke sensor 34 outputs a measurement signal of a voltage value corresponding to the stroke position of the spool 32. The control device 145 identifies the stroke position of the flow control valve 1261 from the measurement signal output by the stroke sensor 34. Since the opening area of ​​the flow control valve 1261 changes with the stroke position, the control device 145 can estimate the opening area (opening degree) from the measurement signal output by the stroke sensor 34.

[0029] Four ports are provided on the side of the valve body 31 that penetrate into the sliding space 311. Specifically, the valve body 31 is provided with a first main port 312 and a second main port 313 through which hydraulic fluid for supplying the actuator flows, and a pilot port 314 and an air vent port 315 through which hydraulic fluid for supplying pilot pressure flows. The first main port 312 and the second main port 313 are provided on the side of the valve body 31 at positions that face the groove of the spool 32 when the spool 32 contacts the first stopper 316, and face the grooveless side of the spool 32 when the spool 32 contacts the second stopper 317. The first main port 312 is connected to the main oil passage 123, and the second main port 313 is connected to the pressure compensation valve 1262. The pilot port 314 is provided on the side of the valve body 31 at a position on the second end face side of the second stopper 317. In the first embodiment, the air vent port 315 is provided near the stroke end on the first end face side of the spool 32. The air vent port 315 is in electrical contact with the pilot port 314 when the spool 32 is in the position near the stroke end on the first end face side (air vent position). The air vent port 315 is connected to a tank for recovering oil. In other embodiments, the air vent port 315 may be provided near the stroke end on the second end face side of the spool 32.

[0030] Hydraulic fluid for supplying pilot pressure is supplied from the pilot port 314, and by pushing the spool 32, the position of the groove in the spool sandwiched between the first main port and the second main port changes. This allows the flow control valve 1261 to adjust the flow rate of the hydraulic fluid.

[0031] The air vent port 315 is a port provided to allow hydraulic fluid containing dissolved air to flow into the tank. Hydraulic fluid can contain dissolved air, and when pressure is applied to the hydraulic fluid, the dissolved air contracts, making it difficult to efficiently transfer energy. Also, when the hydraulic fluid changes from high pressure to low pressure, the dissolved air is released as bubbles due to the decrease in saturation solubility. These bubbles generated from the hydraulic fluid contribute to cavitation. Therefore, it is necessary to remove the air from the hydraulic fluid (vent the air). Since the inside of the tank is kept at atmospheric pressure, which is lower than the sliding space 311, when hydraulic fluid flows from the air vent port 315 into the tank, the dissolved air is released as bubbles due to the decrease in saturation solubility. In addition, tanks usually have a structure to remove bubbles. A back pressure valve is provided upstream of the tank, and the pressure upstream of the back pressure valve is maintained at a predetermined lower limit pressure.

[0032] The air vent port 315 is located near the stroke end of the spool 32. This prevents hydraulic fluid from leaking from the air vent port 315 when the spool 32 has not reached the stroke end, thus preventing a decrease in responsiveness and fuel efficiency.

[0033] The hydraulic fluid supplied to the pilot port 314 is supplied from the hydraulic pump 122. The hydraulic pump 122 (for example, the front hydraulic pump 122A) is equipped with a priority valve (not shown) that preferentially reserves hydraulic fluid for supply to the pilot port 314. The priority valve reserves hydraulic fluid to a predetermined set pressure (pilot pressure). The hydraulic fluid reserved by the priority valve is reduced to a pressure corresponding to the control amount by electromagnetic proportional valves (not shown) provided for each hydraulic component, and then supplied to the pilot port 314.

[0034] Furthermore, other hydraulic components such as the bleed valve 1232, the main confluence / separation valve 1241, and the LS confluence / separation valve 1291 also have air venting structures (pilot port and air venting port) similar to those of the flow control valve 1261. The cylinder block of the hydraulic pump 122 according to the first embodiment does not have an air venting structure because it is driven by the pressure of the hydraulic fluid discharged by the hydraulic pump 122. On the other hand, if the cylinder block of the hydraulic pump 122 according to other embodiments is driven by hydraulic fluid secured by a priority valve, the cylinder block may also have an air venting structure.

[0035] 《Configuration of Control Device 145》 Figure 4 is a schematic block diagram showing the configuration of the control device 145 according to the first embodiment. The control device 145 according to the first embodiment includes a measurement value acquisition unit 51, an operation amount acquisition unit 52, a target flow rate determination unit 53, a pump control unit 54, a valve control unit 55, an air bleeding unit 56, and a calibration unit 57.

[0036] The measurement value acquisition unit 51 acquires measurement signals from various sensors (front pump discharge pressure sensor 1231A, rear pump discharge pressure sensor 1231B, slewing load pressure sensor 127P, arm load pressure sensor 132CP, front travel load pressure sensor 112RP, boom load pressure sensor 131CP, bucket load pressure sensor 133CP, rear travel load pressure sensor 112LP, and hydraulic component stroke sensor 34). The measurement signals may be, for example, voltage signals. The measurement value acquisition unit 51 acquires sensor data indicating the measurement value from the measurement signals based on a signal-measurement value conversion table corresponding to the various sensors. If the front control valve 126A or the rear control valve 126B has a port for supplying hydraulic fluid to the attachment, the work machine 1 may also be equipped with a load pressure sensor for the attachment. The operation amount acquisition unit 52 receives operation commands from the operation device 142 and identifies the operation amount of each actuator. Furthermore, if the work machine 1 has an automatic control function, the operation amount acquisition unit 52 may acquire the operation amount calculated by the automatic control function.

[0037] The target flow rate determination unit 53 determines a target value for the hydraulic fluid flow rate required to drive each actuator according to the manipulated amount acquired by the manipulated amount acquisition unit 52. The target flow rate determination unit 53 determines the required flow rate corresponding to the manipulated amount based on a conversion table that shows the relationship between the manipulated amount of each actuator and the required flow rate, which is predetermined. On the other hand, since the discharge amount of the hydraulic pump 122 does not change instantaneously, it takes time for the hydraulic fluid flow rate to reach the required flow rate. Therefore, the target flow rate determination unit 53 predicts the target flow rate in the actuator unit U after a predetermined time based on the current target value of the hydraulic fluid flow rate calculated from the measured value of the swash plate angle sensor 1221 acquired by the measurement value acquisition unit 51, and the sum of the required flow rates.

[0038] The pump control unit 54 controls the swash plate angle of each hydraulic pump 122. Specifically, the pump control unit 54 generates a command signal from the target value of the swash plate angle based on a control table for converting the target value of the swash plate angle into a command signal for the cylinder block of the hydraulic pump 122. The command signal may be, for example, a current signal. The cylinder block is supplied with hydraulic fluid at a pressure corresponding to the command signal. The valve control unit 55 controls the opening degree of the flow rate adjustment valve 1261 and the bleed valve 1232 of each control valve 126 based on the target flow rate determined by the target flow rate determination unit 53 and the merging and separation state of the main oil passage 123. As described above, since the target flow rate determination unit 53 determines the target value of the flow rate based on the current flow rate of hydraulic fluid and the requested flow rate, the target value of the flow rate does not necessarily coincide with the requested flow rate. In other words, even if the amount of operation of the operating device 142 by the operator is at its maximum, the target value of the flow rate of hydraulic fluid supplied to the corresponding actuator may not be at its maximum. The valve control unit 55 generates a command signal from the target flow rate value based on a control table for converting the target flow rate value into a command signal for the flow control valve 1261 and the spool 32 of the bleed valve. The command signal may be, for example, a current signal.

[0039] The air bleeding section 56 performs air bleeding on hydraulic components having air bleeding structures, such as the flow control valve 1261, the cylinder block of the hydraulic pump 122, and the bleed valve 1232, in response to an operation from the operator. Details of the air bleeding process will be described later.

[0040] The calibration processing unit 57 performs calibration processing on the control table used to control hydraulic components such as the flow control valve 1261, hydraulic pump 122, and bleed valve 1232, and on the signal-measured value table used to obtain measured values ​​from the measurement signals of the hydraulic components, in response to operations from the operator. The calibration processing will be described later.

[0041] <Air Bleeding Process> Operators and service technicians input an instruction to start the air bleeding process to the control device 145 in order to perform the air bleeding process on the hydraulic components of the work machine 1. The hydraulic components to be bled according to the first embodiment are each flow control valve 1261, each bleed valve 1232, main junction / separation valve 1241, and LS junction / separation valve 1291, which have an air bleeding structure. The air bleeding process is performed, for example, when assembling the work machine 1 (before shipment) or when replacing hydraulic components. The instruction to start the air bleeding process is given, for example, by pressing the air bleeding process button, operating the monitor 146 provided in the operator's cab 140, or by operating a terminal held by a service technician.

[0042] When the air bleeding processing unit 56 receives an instruction to start the air bleeding process, it displays an instruction screen on a predetermined monitor 146 that instructs the unit to prepare for starting the air bleeding process. Figure 5 is a diagram showing an example of an instruction screen according to the first embodiment. The instruction screen displays instructions to confirm that the surrounding area is safe and on level ground (horizontal or nearly horizontal ground), to raise the hydraulic oil temperature to a specified temperature (warm-up instruction), to set the work machine 130 to a predetermined preparation position, to engage the slewing lock, and to set the fuel dial to the minimum. The preparation position is, for example, a position where the bucket 133 is rotated to the maximum extent towards the excavation side, the arm 132 is excavating to the maximum extent, and the boom 131 is lowered so that the tip of the arm 132 touches the ground. The instruction screen also displays the status of the slewing brake, the amount the fuel dial is operated, the specified temperature of the hydraulic oil, and the actual temperature of the hydraulic oil. The specified temperature of the hydraulic oil is a predetermined reference value. The conditions for starting the air bleeding process are that the swing brake is ON, the fuel dial is at 0%, and the hydraulic fluid temperature is above the specified temperature. The operator follows the displayed instructions to park the work machine 1 on level ground, warm up the engine to raise the hydraulic fluid temperature, prepare the work machine 130 for use, engage the swing lock, and set the fuel dial to the minimum.

[0043] By raising the hydraulic fluid temperature to the specified temperature before performing the air bleeding process, it is possible to prevent the hydraulic components from losing smooth movement due to thermal shock. In addition, by turning on the swing brake before performing the air bleeding process, it is possible to suppress the movement of the swing body 120 during the air bleeding process.

[0044] The measurement value acquisition unit 51 acquires sensor data from various sensors and obtains the operating amount of the operating device 142. The air bleeding processing unit 56 updates the swivel lock status, the operating amount of the fuel dial, and the hydraulic fluid temperature on the instruction screen based on the data acquired by the measurement value acquisition unit 51. At this time, the swivel lock status, the operating amount of the fuel dial, and the hydraulic fluid temperature, which are related to the start conditions of the air bleeding process, are displayed in different colors depending on whether the conditions are met or not. For example, items that meet the conditions may be displayed in green, and items that do not meet the conditions may be displayed in red.

[0045] Next, the air bleeding processing unit 56 determines whether all the start conditions for the air bleeding process are satisfied based on the data acquired by the measurement value acquisition unit 51. That is, the air bleeding processing unit 56 determines whether the swing lock is ON, the fuel dial is 0%, and the temperature of the hydraulic oil is equal to or higher than the specified temperature. The operator operates the work machine 1 so as to satisfy the start conditions for the air bleeding process.

[0046] When all the start conditions for the air bleeding process are satisfied, the air bleeding processing unit 56 can start the air bleeding process. The air bleeding processing unit 56 according to the first embodiment starts the air bleeding process after receiving a predetermined operation from the operator in a state where the start conditions are satisfied. The predetermined operation is a physical operation on the operation device 142 provided in the cab 140. Specifically, the predetermined operation may be an operation of a lock lever or pressing a physical button. By starting the air bleeding process after receiving a predetermined operation from the operator, the control device 145 recognizes that the air bleeding process has been started according to the intention of the operator in the cab 140, and can prevent the air bleeding process from being started against the intention of the operator due to external intervention or the like. The air bleeding processing unit 56 causes the monitor 146 to display a confirmation screen for instructing the operator to perform a predetermined operation until a predetermined operation is received after the start conditions are satisfied.

[0047] Figure 6 shows an example of a command signal transmitted to a hydraulic component during the air bleeding process in the first embodiment. The air bleeding processing unit 56 repeatedly inputs a first current value and a second current value for a hydraulic component. The first current value is the current value that supplies hydraulic fluid at a pressure necessary to push the spool 32 of the hydraulic component to the stroke end on the first end side. The second current value is the current value that supplies hydraulic fluid at a pressure that allows the spool 32 to move to the stroke end on the second end side by the restoring force of the spring 33 of the hydraulic component. In this embodiment, the opening area of ​​the spool is maximum at the first end and minimum at the second end, but it is not limited to this. For example, in other embodiments, the opening area of ​​the spool may be minimum at the first end and maximum at the second end. It is preferable that the second current value is greater than zero. A second current value greater than zero reduces the time lag until the spool 32 is moved back to the first end side. The command signal shown in Figure 6 has an agitation phase in which the current value is switched between a first current value and a second current value at unit time intervals, followed by an air-bleeding phase in which the first current value is maintained. The speed at which the current value is switched from the first to the second current value in unit time is faster than the speed at which the spool 32 is moved for operation of the actuator by the operating device 142. The following explanation assumes that the unit time is 100 milliseconds, but the unit time is not limited to 100 milliseconds in other embodiments. For example, the period of the agitation phase waveform may be 200 milliseconds, the length of the agitation phase may be two periods of the agitation phase waveform, and the length of the air-bleeding phase may be 3 seconds. Here, the timing at which the current value of the command signal rises to the first current value is considered as the starting point of the period of the agitation phase waveform. Due to the agitation phase of the command signal, the spool 32 of the hydraulic component rapidly reciprocates between the stroke end on the first end side and the stroke end on the second end side. This creates turbulence in the hydraulic fluid. This promotes the circulation of the hydraulic fluid in dead ends and corners where hydraulic fluid tends to stagnate. In particular, when the spool 32 moves at high speed from the second end of the stroke to the first end of the stroke, the space created by the movement of the spool 32 becomes negatively pressurized, generating a suction force, which can move the hydraulic fluid in corners and dead ends.Note that the cycle of the stirring period, the length of the stirring period, the waveform of the command signal for the stirring period, and the length of the air bleeding period are not limited to the example shown in FIG. 6.

[0048] In the air bleeding process, since the hydraulic oil is filled into the space generated by moving the spool 32, a large amount of the hydraulic oil secured by the priority valve is consumed. When the consumption flow rate exceeds the supply flow rate, the pressure (pilot source pressure) secured by the priority valve decreases. When the pilot pressure supplied to each hydraulic component decreases due to the decrease in the pilot source pressure, even if a command signal with the first current value is output, the spool 32 does not reach the stroke end, and the air bleeding port 315 remains blocked. To suppress the consumption flow rate of the pilot hydraulic oil due to the movement of the hydraulic components, the air bleeding processing unit 56 according to the first embodiment outputs a command signal such that only one hydraulic component moves from the second end side to the first end side at a certain time among the command signals transmitted to the plurality of hydraulic components.

[0049] FIG. 7 is a diagram showing a time chart (part 1) of the command signal according to the first embodiment. The air bleeding processing unit 56 outputs a command signal in the following procedure. In the following example, it is assumed that the cycle of the stirring period is 200 milliseconds, and the length of the stirring period is two cycles (400 milliseconds) of the stirring period waveform. Also, it is assumed that the response delay time of the hydraulic component is sufficiently shorter than the half cycle of the stirring period waveform. First, the air bleeding processing unit 56 sets the current value of all the flow rate adjustment valves 1261 to zero. Next, the air bleeding processing unit 56 drives the hydraulic pump 122 at a predetermined flow rate sufficient for supplying the pilot source pressure. The air bleeding processing unit 56 drives the hydraulic pump 122 at a flow rate larger than the hydraulic oil consumed by the movement of the spool 32 by the command signal in the stirring period.

[0050] The air bleeding unit 56 outputs a command signal for the first current value to the rear bleed valve 1232B. This causes the rear bleed valve 1232B to open completely. Next, the air bleeding unit 56 starts outputting a command signal for air bleeding to the front bleed valve 1232A. Two cycles (400 milliseconds) after the air bleeding command signal is started to be output to the front bleed valve 1232A (after the end of the stirring period), the air bleeding unit 56 outputs a command signal for the second current value to the rear bleed valve 1232B. This causes the rear bleed valve 1232B to close completely. In this example, the air bleeding unit 56 also starts outputting a command signal for air bleeding to the main confluence separation valve 1241 two cycles (400 milliseconds) after the air bleeding command signal is started to be output to the front bleed valve 1232A (after the end of the stirring period). In this example, the command signal for air bleeding is output to the LS confluence separation valve 1291 100 milliseconds after the main confluence separation valve 1241 starts outputting the command signal for air bleeding (half a cycle after the stirring phase). At the start of the air bleeding process for the main confluence separation valve 1241 and the LS confluence separation valve 1291, the command signal for the front bleed valve 1232A has entered the air bleeding phase, so the front bleed valve 1232A is fully open.

[0051] The air bleeding section 56 outputs a command signal for the first current value to the rear bleed valve 1232B two cycles (400 milliseconds) after it has started outputting a command signal for air bleeding to the LS confluence separation valve 1291 (after the end of the stirring period). At the start of the air bleeding process for the rear bleed valve 1232B, the command signal for the front bleed valve 1232A has entered the air bleeding period, so the front bleed valve 1232A is fully open.

[0052] Figure 8 shows a time chart (part 2) of the command signal according to the first embodiment. First, as preparation for the air bleeding process shown in Figure 8, the air bleeding processing unit 56 fully opens the bleed valve 1232 and the main confluence separation valve 1241, and fully closes the flow rate adjustment valve 1261 (meter-out valve) on the outlet side of the actuator. In this way, the air bleeding processing unit 56 prevents the hydraulic fluid discharged by the hydraulic pump 122 from flowing into the inlet of the flow rate adjustment valve 1261 by releasing it through the two bleed valves, and further prevents the work machine 130 from moving during the adjustment process by blocking the outlet. The air bleeding processing unit 56 prepares for the start of the air bleeding process shown in Figure 8 by supplying a second command current value to the inlet-side flow rate adjustment valve 1261 (meter-in valve) and putting it into standby mode.

[0053] Next, the air bleeding processing unit 56 starts outputting an air bleeding command signal to the meter-in valve (boom lowering meter-in valve) for driving the boom 131 downwards.

[0054] 300 milliseconds after the boom lowering meter-in valve starts outputting a command signal for air venting (a timing half a cycle earlier than the length of the stirring period waveform), the air venting processing unit 56 starts outputting a command signal for air venting to the meter-in valve (bucket drilling meter-in valve) that drives the bucket 133 in the drilling direction. In this example, the command signal for air venting switches between the first current value and the second current value every 100 milliseconds during the stirring period. Therefore, by starting to output the command signal for air venting to the bucket drilling meter-in valve 300 milliseconds after the boom lowering meter-in valve starts outputting the command signal for air venting, the command signals for the stirring period at the boom lowering meter-in valve and the bucket drilling meter-in valve are in opposite phase. This prevents the boom lowering meter-in valve and the bucket drilling meter-in valve from moving simultaneously from the second end to the first end.

[0055] 300 milliseconds after the start of outputting a command signal for air bleeding to the bucket drilling meter-in valve, the air bleeding processing unit 56 starts outputting a command signal for air bleeding to the meter-in valve for driving the boom 131 in the upward direction (boom-raising meter-in valve). In this example, since the agitation phase of the air bleeding process is two cycles (400 milliseconds), 600 milliseconds after the start of outputting a command signal for air bleeding to the boom-down meter-in valve, the command signal for the boom-down meter-in valve is in the air bleeding phase.

[0056] 300 milliseconds after the boom lifting meter-in valve starts outputting a command signal for air venting, the air venting processing unit 56 starts outputting a command signal for air venting to the meter-in valve (bucket soil discharge meter-in valve) for driving the bucket 133 in the soil discharge direction. 300 milliseconds after the bucket soil discharge meter-in valve starts outputting a command signal for air venting, the air venting processing unit 56 starts outputting a command signal for air venting to the meter-in valve (arm soil discharge meter-in valve) for driving the arm 132 in the soil discharge direction. 300 milliseconds after the arm soil discharge meter-in valve starts outputting a command signal for air venting, the air venting processing unit 56 starts outputting a command signal for air venting to the meter-in valve (right-swing meter-in valve) for driving the slewing body 120 to the right. 300 milliseconds after the right-swing meter-in valve starts outputting a command signal for air venting, the air venting processing unit 56 starts outputting a command signal for air venting to the meter-in valve (arm excavation meter-in valve) for driving the arm 132 in the excavation direction. 300 milliseconds after the arm drilling meter-in valve starts outputting a command signal for air bleeding, the air bleeding processing unit 56 starts outputting a command signal for air bleeding to the meter-in valve (left-rotating meter-in valve) for driving the rotating body 120 to the left.

[0057] Next, in preparation for bleeding the air from the meter-out valve, the air bleeding unit 56 completely closes the flow control valve 1261 (meter-in valve) on the inlet side of the actuator. This prevents the work machine from being driven by the hydraulic fluid discharged by the hydraulic pump 12 during the air bleeding process. The air bleeding unit 56 then supplies a second command current value to the inlet-side flow control valve 1261 (meter-out valve) and puts it into standby mode, preparing to start the process.

[0058] Next, the air bleeding processing unit 56 starts outputting an air bleeding command signal to the meter-out valve (boom-lowering meter-out valve) for driving the boom 131 in the downward direction.

[0059] 300 milliseconds after the boom lowering meter-out valve starts outputting a command signal for air venting (an odd multiple of half a cycle of the mixing phase waveform), the air venting unit 56 starts outputting a command signal for air venting to the meter-out valve (bucket drilling meter-out valve) that drives the bucket 133 in the drilling direction. The command signal for air venting switches between a first current value and a second current value every 100 milliseconds during the mixing phase. Therefore, by starting to output the command signal for air venting to the bucket drilling meter-out valve 300 milliseconds after the boom lowering meter-out valve starts outputting the command signal for air venting, the command signals for the mixing phase at the boom lowering meter-out valve and the bucket drilling meter-out valve are in opposite phase. This prevents the boom lowering meter-out valve and the bucket drilling meter-out valve from moving simultaneously from the second end to the first end.

[0060] 300 milliseconds after the start of outputting a command signal for air bleeding to the bucket drilling meter-out valve, the air bleeding processing unit 56 starts outputting a command signal for air bleeding to the meter-out valve (boom-raising meter-out valve) that drives the boom 131 in the upward direction. Since the agitation phase of the air bleeding process is two cycles (400 milliseconds), 600 milliseconds after the start of outputting a command signal for air bleeding to the boom-down meter-out valve, the command signal for the boom-down meter-out valve is in the air bleeding phase.

[0061] 300 milliseconds after the air venting command signal is started to be output to the boom lifting meter-out valve, the air venting processing unit 56 starts outputting an air venting command signal to the meter-out valve (bucket soil discharge meter-out valve) for driving the bucket 133 in the soil discharge direction. 300 milliseconds after the air venting command signal is started to be output to the bucket soil discharge meter-out valve, the air venting processing unit 56 starts outputting an air venting command signal to the meter-out valve (arm soil discharge meter-out valve) for driving the arm 132 in the soil discharge direction. 300 milliseconds after the air venting command signal is started to be output to the arm soil discharge meter-out valve, the air venting processing unit 56 starts outputting an air venting command signal to the meter-out valve (right-swing meter-out valve) for driving the slewing body 120 to the right. 300 milliseconds after the air venting command signal is started to be output to the right-swing meter-out valve, the air venting processing unit 56 starts outputting an air venting command signal to the meter-out valve (arm excavation meter-out valve) for driving the arm 132 in the excavation direction. 300 milliseconds after the arm drilling meter-out valve starts outputting a command signal for air bleeding, the air bleeding processing unit 56 starts outputting a command signal for air bleeding to the meter-out valve (left-rotating meter-out valve) for driving the rotating body 120 to the left.

[0062] According to the procedure described above, the air bleeding unit 56 outputs a command signal so that only one hydraulic component moves from the second end to the first end. This prevents the air bleeding unit 56 from losing pilot pressure. In addition, while the air bleeding unit 56 is performing air bleeding on one of the meter-in valves and the meter-out valve, it completely closes the other valve. This allows the air bleeding unit 56 to suppress the operation of the actuator during air bleeding. However, since the pressure-receiving area of ​​the power cylinder differs between the head and bottom sides, it may not completely stop even if one port is closed. Therefore, by having the work implement 130 assume a ground-contacting position during air bleeding, it is possible to suppress the movement of the work implement 130 due to gravity and the movement of the vehicle body due to the reaction force of the ground. In addition, while the air bleeding unit 56 is performing air bleeding on the flow control valve 1261, it fully opens the bleed valve 1232. This prevents the meter-in pressure from becoming excessively high.

[0063] Calibration Process Operators, service personnel, and other workers input a calibration process start command to the control device 145 in order to perform a calibration process on the hydraulic components of the work machine 1. The hydraulic components to be calibrated are hydraulic components whose position is measured by a stroke sensor. Specifically, in the first embodiment, the hydraulic components to be calibrated are each hydraulic pump 122, each flow control valve 1261, and each bleed valve 1232. The calibration process is performed, for example, during the assembly of the work machine 1 (before shipment) or during maintenance. The instruction to start the calibration process is given, for example, by pressing a calibration process button or by operating a monitor 146 provided in the operator's cab 140. In other embodiments, the calibration process may be performed automatically following the air bleeding process without inputting a start command.

[0064] When the calibration processing unit 57 receives a signal to start the calibration process, it displays an instruction screen on a predetermined monitor 146, as shown in Figure 5, instructing the system to prepare for the start of the calibration process. The conditions for starting the calibration process are the same as the conditions for starting the air bleeding process.

[0065] The calibration procedure for each hydraulic component will now be explained. First, the calibration processing unit 57 outputs a command signal with a current value of zero to the hydraulic component. As a result, the spool 32 comes into contact with the stroke end on the second end side. The calibration processing unit 57 acquires a measurement signal from the stroke sensor 34 of the hydraulic component. As a result, the calibration processing unit 57 determines the value of the measurement signal when the spool 32 is positioned at the stroke end on the second end side.

[0066] Next, the calibration processing unit 57 repeatedly increases the current value of the command signal by a unit amount and waits for a sufficient waiting time (e.g., 1 second) to elapse for the spool 32 to move due to the command signal. During this time, the calibration processing unit 57 acquires a measurement signal from the stroke sensor 34 of the hydraulic component. For each current value of the command signal, the calibration processing unit 57 identifies a pair of command signal values ​​and measurement signal values ​​by taking the average value of the time series of measurement signals acquired during the waiting time. In other embodiments, the calibration processing unit 57 may identify a pair of command signal values ​​and measurement signal values ​​based on the measurement signal acquired after the waiting time has elapsed. The calibration processing unit 57 repeats the process of increasing the current value of the command signal by a unit amount to identify a pair of command signal values ​​and measurement signal values ​​until the current value of the command signal becomes a current value sufficient to move the spool 32 to the stroke end on the first end side. As a result, the spool 32 comes into contact with the stroke end on the first end side, and the calibration processing unit 57 can identify the measurement signal value when the spool 32 is located at the stroke end on the first end side. Next, the calibration processing unit 57 decreases the current value of the command signal by a unit amount and repeats the process of identifying a pair of the command signal value and the measurement signal value until the current value of the command signal becomes zero.

[0067] By following the procedure described above, the calibration processing unit 57 can identify the value of the measurement signal when the spool 32 is located at the first end stroke, the value of the measurement signal when the spool 32 is located at the second end stroke, the pair of the command signal value and the measurement signal value when the command signal is increasing, and the pair of the command signal value and the measurement signal value when the command signal is decreasing. In the procedure described above, the calibration processing unit 57 outputs a command signal that changes the current value in steps at each waiting time, but this is not limited to other embodiments. For example, in other embodiments, the calibration processing unit 57 may acquire the measurement signal while continuously changing the command signal at a sufficiently slow speed (for example, a speed at which the current value increases or decreases by a unit amount in enough time for the spool 32 to move), and identify the pair of the command signal value and the measurement signal value based on this.

[0068] The calibration processing unit 57 updates the signal-measured value conversion table, which shows the relationship between the measured signal value and the position of the spool 32, by linear interpolation based on the pair of the position of the first end stroke and the measured signal value, and the pair of the position of the second end stroke and the measured signal value.

[0069] Next, the calibration processing unit 57 converts the value of the measured signal to the position of the spool 32 based on the signal-measured value conversion table for each pair of command signal value and measured signal value when the command signal is increasing, and when the command signal is decreasing. This allows the calibration processing unit 57 to identify the pair of command signal value and spool 32 position when the command signal is increasing, and when the command signal is decreasing.

[0070] The calibration processing unit 57 extracts the command signal value and spool 32 position pair when the spool 32 is not located at the stroke end from the command signal value and spool 32 position pair when the command signal is increasing, and when the command signal is decreasing. For example, the calibration processing unit 57 identifies pairs where the difference between the spool 32 position and the stroke end position exceeds a predetermined threshold as the command signal value and spool 32 position pair when the spool 32 is not located at the stroke end. As a result, the calibration processing unit 57 identifies the minimum command signal value when the spool 32 is located at the first end stroke end and the maximum command signal value when the spool 32 is located at the second end stroke end. The command signal range when the spool 32 is located at the first end stroke end and the command signal range when the spool 32 is located at the second end stroke end are dead zones where the spool 32 position does not change even if the control signal changes.

[0071] The calibration processing unit 57 determines the relationship between the command signal value and the position of the spool 32 between stroke ends by performing regression analysis (e.g., least squares method, steepest descent method, machine learning method, Bayesian estimation, etc.) based on the pair of command signal value and spool 32 position when the spool 32 is not located at the stroke end. The calibration processing unit 57 determines the relationship between the command signal value and the position of the spool 32 by using the pair of command signal value and spool 32 position when the command signal is increasing, and the pair of command signal value and spool 32 position when the command signal is decreasing, thereby eliminating measurement errors and the effects of hysteresis associated with increases and decreases.

[0072] The calibration processing unit 57 updates the control table based on the relationship between the command signal value and the position of the spool 32 between stroke ends.

[0073] Calibration processing is performed on each hydraulic component one by one in sequence, which takes a long time. Calibration processing can be shortened by performing calibration processing on multiple hydraulic components simultaneously. On the other hand, if the calibration processing of the meter-in valve and meter-out valve is performed simultaneously, there is a possibility that the work machine 130 will start moving. Therefore, the calibration processing unit 57 according to the first embodiment first performs calibration processing on the two bleed valves 1232, then performs calibration processing on the multiple meter-out valves and the two hydraulic pumps 122, and finally performs calibration processing on the multiple meter-in valves. In this way, the calibration processing unit 57 according to the first embodiment can perform calibration processing in a short time while preventing the work machine 130 from starting and preventing engine stalls.

[0074] When calibrating the hydraulic pump 122, the calibration processing unit 57 increases the command signal of the bleed valve 1232 in accordance with the increase in the command signal of the hydraulic pump 122. Specifically, while the command signal of the hydraulic pump 122 is below a predetermined threshold, the calibration processing unit 57 keeps the bleed valve 1232 completely closed. In the first embodiment, the hydraulic pump 122 is a hydraulic pump that controls the swash plate using discharge pressure, and in order to secure discharge pressure, the bleed valve 1232 is kept completely closed while the pump capacity is small. On the other hand, if the bleed valve 1232 remains completely closed even when the pump capacity increases, the discharge pressure will increase, and the load torque of the hydraulic pump 122 may become excessive relative to the output torque of the engine 121, potentially causing the rotational speed of the engine 121 to decrease. To prevent this, in the first embodiment, the calibration processing unit 57 increases the opening area of ​​the bleed valve 1232 in accordance with the increase in pump capacity to prevent the discharge pressure from becoming excessive.

[0075] The calibration processing unit 57 determines whether the signal-measured value conversion table and control table updated by calibration deviate from a predetermined variation range with respect to the signal-measured value conversion table and control table at the time of design. For example, the calibration processing unit 57 determines that there is an abnormality if the difference or ratio of the numerical values ​​between the control table set as a standard at the time of design and the control table updated by calibration exceeds a threshold, and issues an alarm. The alarm may be issued, for example, by displaying an alarm screen on the monitor 146 that includes identification information of the hydraulic component whose correlation coefficient falls below the threshold, or by emitting an alarm sound.

[0076] 《Operation and Effects》 The control device 145 according to the first embodiment performs air bleeding or calibration as an adjustment process to improve the control accuracy of hydraulic components by driving adjustment members such as the spool 32 and swash plate. By performing air bleeding, the control device 145 can transport the hydraulic fluid containing dissolved air to the tank and remove the air from the hydraulic fluid. By removing air, which has a low bulk modulus, from the hydraulic fluid, the control device 145 can improve the control accuracy by pilot pressure. Furthermore, by performing calibration, the control device 145 can update the relationship between the values ​​of the measurement signal and the command signal and the position of the adjustment member. Due to the effects of assembly errors and aging deterioration, variations occur in the relationship between the signal value and the position of the adjustment member in hydraulic components. Therefore, the control device 145 can improve control accuracy by actually driving the adjustment member and performing calibration.

[0077] In the first embodiment, the calibration processing unit 57 determines the relationship between the command signal value and the position of the spool 32 based on the pair of the command signal value and the position of the spool 32 when the command signal increases, and the pair of the command signal value and the position of the spool 32 when the command signal decreases, but is not limited to this. For example, the calibration processing unit 57 in another embodiment may determine the relationship between the command signal value and the position of the spool 32 based on the pair of the command signal value and the position of the spool 32 when the command signal increases, that is, without using the pair of the command signal value and the position of the spool 32 when the command signal decreases. In this case, the calibration processing unit 57 can improve the responsiveness and accuracy when the operating device 142 is tilted from the neutral position.

[0078] In the first embodiment, the control device 145 displays an instruction on the instruction screen for air bleeding or calibration (adjustment) to move the work machine 130 to a predetermined ready position. In the first embodiment, the ready position is one in which the bucket 133 is rotated to its maximum extent toward the excavation side, the arm 132 is excavating to its maximum extent, and the boom 131 is lowered so that the tip of the arm 132 touches the ground, but in other embodiments, it is not limited to this. For example, in other embodiments, the adjustment process for the flow control valve 1261 on the excavation side of the work machine 130 and the adjustment process for the flow control valve 1261 on the soil discharge side of the work machine 130 may be performed separately. The ready position for the adjustment process for the flow control valve 1261 on the excavation side of the work machine 130 may be one in which the boom 131, arm 132, and bucket 133 are moved to the end of the movable range (stroke end) toward the excavation side. By positioning the boom 131, arm 132, and bucket 133 at the stroke end on the excavation side, it is possible to prevent the work machine 130 from moving even if hydraulic fluid flows to the flow control valve 1261 on the excavation side. Similarly, the preparatory position for adjusting the flow control valve 1261 on the soil discharge side of the work machine 130 may be a position in which the boom 131, arm 132, and bucket 133 are moved to the end of the movable range (stroke end) on the soil discharge side.

[0079] <Computer Configuration> Figure 9 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. The computer 90 includes a processor 91, main memory 92, storage 93, and interface 94. The control device 145 described above is implemented in the computer 90. The operation of each of the above-described processing units is stored in the storage 93 in the form of a program. The processor 91 reads the program from the storage 93, loads it into the main memory 92, and executes the above-described processing according to the program. The processor 91 also allocates storage areas in the main memory 92 corresponding to each of the above-described storage units according to the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0080] The program may be for implementing a part of the functions to be performed by the computer 90. For example, the program may perform functions in combination with other programs already stored in storage, or in combination with other programs implemented on other devices. In other embodiments, the computer 90 may include a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to, or instead of, the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also included as an example of a processor. In other embodiments, the computer 90 may be virtualized on one or more computers.

[0081] Examples of storage 93 include magnetic disks, magneto-optical disks, optical disks, and semiconductor memory. Storage 93 may be an internal medium directly connected to the bus of the computer 90, or it may be an external medium connected to the computer 90 via an interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via a communication line, the computer 90 that receives the distribution may expand the program into the main memory 92 and execute the above processing. In at least one embodiment, storage 93 is a tangible storage medium that is not temporary.

[0082] Furthermore, the program may be intended to implement some of the functions described above. In addition, the program may be a so-called differential file (differential program) that implements the functions described above in combination with other programs already stored in the storage 93.

[0083] According to the above embodiment, the working machine can improve the control accuracy of its hydraulic components.

[0084] 1...Working machine 110...Traveling body 120...Slewing body 121...Engine 122...Hydraulic pump 1261...Flow control valve 127...Slewing motor 130...Working machine 131...Boom 131C...Boom cylinder 132...Arm 132C...Arm cylinder 133...Bucket 133C...Bucket cylinder 140...Operator's cab 142...Operating device 145...Control device 146...Monitor 150...Machine room 20...Drive system 31...Valve body 311...Sliding space 312...First main port 313...Second main port 314...Pilot port 315...Air vent port 316...First stopper 317...Second stopper 32...Spool 33...Spring 34...Stroke sensor

Claims

1. A working machine comprising: a hydraulic component that controls the hydraulic fluid by a movable adjustment member; and a controller that controls the hydraulic component, wherein the controller drives the adjustment member to perform an adjustment process that improves the control accuracy of the hydraulic component.

2. The work machine according to claim 1, comprising a plurality of hydraulic components including the hydraulic component, wherein the adjustment process includes driving the adjustment member of a first hydraulic component which is one of the plurality of hydraulic components, and driving the adjustment member of a second hydraulic component which is one of the plurality of hydraulic components at a different timing than that of the first hydraulic component.

3. The work machine according to claim 1, comprising: a hydraulic pump which is a hydraulic component equipped with a swash plate which is an adjustment member; and a meter-in valve which is a hydraulic component equipped with a valve body which is an adjustment member, through which hydraulic fluid flowing into an actuator flows, wherein the adjustment process is performed such that the adjustment process relating to the hydraulic pump is performed at a different timing than the adjustment process relating to the meter-in valve.

4. The work machine according to claim 1, comprising: a hydraulic pump which is a hydraulic component equipped with a swash plate which is an adjustment member; and a bleed valve which is a hydraulic component for discharging the hydraulic fluid to a tank, wherein the controller controls the opening degree of the bleed valve in accordance with the control of the swash plate of the hydraulic pump while the adjustment process relating to the hydraulic pump is being performed.

5. The work machine according to claim 1, comprising: a hydraulic pump which is a hydraulic component equipped with a swash plate which is an adjustment member; a meter-in valve which is a hydraulic component equipped with a valve body which is an adjustment member and through which hydraulic fluid flowing into an actuator flows; and a bleed valve which is a hydraulic component equipped with a valve body which is an adjustment member and discharges the hydraulic fluid to a tank, wherein the controller performs the adjustment process relating to the bleed valve at a different timing from the adjustment process relating to the hydraulic pump and the adjustment process relating to the meter-in valve.

6. A working machine according to claim 1, comprising: a first oil passage through which hydraulic fluid passes; a second oil passage through which hydraulic fluid passes; a flow control valve provided downstream of the first oil passage, which is a hydraulic component equipped with a valve body that is an adjustment member; a first bleed valve, which is a hydraulic component equipped with a valve body that is an adjustment member, for discharging the hydraulic fluid passing through the first oil passage to a tank; a second bleed valve, which is a hydraulic component equipped with a valve body that is an adjustment member, for discharging the hydraulic fluid passing through the second oil passage to a tank; and a merging passage connecting the first oil passage and the second oil passage, which has a shut-off valve, wherein the controller opens the shut-off valve if the first bleed valve or the second bleed valve is closed while the adjustment process related to the flow control valve is being performed.

7. The work machine according to claim 6, wherein the controller simultaneously performs the adjustment process relating to the flow control valve and the adjustment process relating to the first bleed valve, and opens the second bleed valve while the adjustment process relating to the flow control valve and the adjustment process relating to the first bleed valve are being performed.

8. The working machine according to claim 1, comprising an actuator which is operated by the flow of hydraulic fluid through the hydraulic component, wherein the hydraulic component comprises a valve body and a valve element which is the adjustment member provided in the valve body, and a flow control valve which adjusts the flow rate of hydraulic fluid for operating the actuator depending on the position of the valve element, and having an air vent opening for flowing the hydraulic fluid to a tank when the valve element is in a predetermined air vent position, and the adjustment process includes moving the valve element of the flow control valve to the air vent position to remove air dissolved in the hydraulic fluid of the flow control valve.

9. The working machine according to claim 8, comprising a hydraulic pump which is a hydraulic component that supplies hydraulic fluid for driving the actuator and the adjusting member, wherein the adjustment process includes driving the hydraulic pump such that the amount of hydraulic fluid discharged by the hydraulic pump is greater than the amount of hydraulic fluid consumed to move the valve body of the flow control valve.

10. The working machine according to claim 8, wherein the adjustment process includes moving the valve body to the air vent position at a speed faster than the speed at which the valve body moves for the operation of the actuator.

11. The working machine according to claim 8, wherein the valve body of the flow control valve is biased by an elastic body from the first end to the second end of the valve casing, and the adjustment process includes moving the valve body to the first end and then reducing the pressure of the hydraulic fluid to a second pressure at which the valve body reaches the second end by the biasing of the elastic body, wherein the second pressure is greater than the lower limit pressure determined by the hydraulic circuit.

12. The working machine according to claim 8, wherein the adjustment process includes repeatedly moving the valve body to the first end of the valve casing and moving the valve body to the second end of the valve casing.

13. The working machine according to claim 12, wherein the adjustment process includes repeatedly moving the valve body to the first end of the valve casing, moving the valve body to the second end of the valve casing, and then maintaining the valve body at the air vent position of the valve casing for a certain period of time.

14. The work machine according to claim 1, comprising a sensor that outputs a sensor signal which is an electrical signal corresponding to the position of the adjustment member, wherein the adjustment process includes calibrating the relationship between the position of the adjustment member and the sensor signal based on a first sensor signal which is the sensor signal when the adjustment member is positioned at the first end of the movable range and a second sensor signal which is the sensor signal when the adjustment member is positioned at the second end of the movable range.

15. The work machine according to claim 1, comprising a sensor that outputs a sensor signal which is an electrical signal corresponding to the position of the adjustment member, wherein the adjustment process includes acquiring the sensor signal while changing a control signal which is an electrical signal for controlling the position of the adjustment member, and calibrating the relationship between the target position of the adjustment member and the control signal based on the value of the control signal and the position of the adjustment member indicated by the sensor signal.

16. The working machine according to claim 15, wherein the adjustment process includes moving the adjustment member at a speed such that the flow rate of hydraulic fluid consumed from the hydraulic component due to the movement of the adjustment member does not exceed the flow rate of hydraulic fluid supplied to the hydraulic component.

17. The work machine according to claim 15, wherein the adjustment process includes calibrating the relationship between the target position of the adjustment member and the control signal by regression analysis based on a combination of the value of the control signal and the position of the adjustment member indicated by the sensor signal.

18. The work machine according to claim 15, wherein the adjustment process includes identifying a dead zone in which the position does not change even when the control signal changes, and calibrating the relationship between the target position of the adjustment member and the control signal by regression analysis based on a combination of the value of the control signal in the range excluding the dead zone and the position of the adjustment member indicated by the sensor signal.

19. The work machine according to claim 15, wherein the adjustment process includes acquiring the sensor signal while increasing the control signal; acquiring the sensor signal while decreasing the control signal; and calibrating the relationship between the target position of the adjustment member and the control signal based on the value of the control signal and the position of the adjustment member indicated by the sensor signal when the control signal is increasing, and the value of the control signal and the position of the adjustment member indicated by the sensor signal when the control signal is decreasing.

20. The work machine according to claim 1, comprising a sensor that outputs a sensor signal which is an electrical signal corresponding to the position of the adjustment member, wherein the adjustment process includes determining that the hydraulic component is abnormal if the relationship between the position of the adjustment member and the electrical signal after calibration does not meet a predetermined standard.

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