Calibration system in hydraulic systems

Abstract

To easily perform calibration for setting correspondence between an operation tool manipulated variable and a flow rate of supply to a hydraulic actuator to set relationship.SOLUTION: A control valve 6 which controls a flow rate of supply to a hydraulic actuator 5 comprises a spool valve 8, a pressure compensation valve 9 which holds differential pressure across the spool valve 8 constant, and electromagnetic proportional valves 10A, 10B outputting pilot pressure to the spool valve 8, and is configured to use actual measurement data AD, obtained by measuring the correspondence between output pilot pressure from the electromagnetic proportional valves 10A, 10B and the flow rate of supply from the control valve 6 in a stage before the control valve 6 is mounted on a work machine, to calibrate the correspondence data CD between an operation tool manipulated variable and an output current value to the electromagnetic proportional valves 10A, 10B.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to the technical field of a calibration system in a hydraulic system of a working machine such as a hydraulic excavator.

Background Art

[0002] Generally, a control valve for controlling oil supply and discharge to various hydraulic actuators is provided in a hydraulic system of a working machine such as a hydraulic excavator. Among such control valves, there is one configured using an electromagnetic proportional pressure reducing valve that operates by a control signal output from a controller based on an operation of an operating tool for a hydraulic actuator, and a spool valve that operates by a pilot pressure output from the electromagnetic proportional valve to perform flow control. However, when performing supply flow control to a hydraulic actuator with a control valve configured using such an electromagnetic proportional pressure reducing valve and a spool valve, due to manufacturing tolerances of the electromagnetic proportional pressure reducing valve, etc., there is a variation in the correspondence relationship between the operation amount of the operating tool and the supply flow rate from the control valve to the hydraulic actuator. Even with the same operation amount of the operating tool, the operating speed of the hydraulic actuator may differ for each machine body, and there is a risk that the uniformity of operation will be impaired. To avoid this, calibration is required to make the relationship between the operation amount of the operating tool and the supply flow rate a preset relationship. Therefore, conventionally, an on-off valve structure portion having a passage opening position and a passage blocking position set in relation to the stroke of the spool valve is integrally provided in the spool valve constituting the control valve, and by obtaining the input current value to the electromagnetic proportional valve when the pressure in the measurement passage passing through the on-off valve structure portion changes, the actual measurement characteristics of the input current to the electromagnetic proportional valve and the stroke of the spool valve are obtained, and a technique has been known in which the reference characteristics are calibrated based on the actual measurement characteristics (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] However, the control valve described in Patent Document 1 has a special structure in which the on / off valve structure is integrally formed with the spool valve. Such a special structure of control valve is costly because it can only be manufactured on a custom order basis, and it also becomes large, making it difficult to secure mounting space on the aircraft. There is a need to enable easy calibration without using such a special structure, and this is the problem that the present invention aims to solve. [Means for solving the problem]

[0005] The present invention was created in view of the above circumstances and with the aim of solving these problems, and the invention of claim 1 is a hydraulic system for a work machine comprising a hydraulic actuator, a control valve for controlling the flow rate supplied to the hydraulic actuator, an operating tool operated to drive the hydraulic actuator, and control means for controlling the control valve based on the operation of the operating tool, wherein, in order to perform calibration to set a predetermined relationship between the amount of operation of the operating tool and the flow rate supplied to the hydraulic actuator, the control valve is configured to include a spool valve that opens a supply opening to the hydraulic actuator with an opening area corresponding to the input pilot pressure, a pressure compensation valve that maintains a constant differential pressure across the supply opening of the spool valve, and an electromagnetic proportional valve that outputs a pilot pressure to the spool valve corresponding to the current value output from the control means, and the control means includes correspondence data between the amount of operation of the operating tool and the output current value to the electromagnetic proportional valve, and outputs a current value corresponding to the amount of operation of the operating tool to the electromagnetic proportional valve based on the correspondence data. This hydraulic system calibration system is characterized by the following: a configuration in which the control valve is controlled by the solenoid proportional valve and a calibration system in which calibration is performed using measured data obtained by actually measuring the correspondence between the output pilot pressure from the solenoid proportional valve and the supply flow rate output from the control valve before the control valve is mounted on the work machine; a calibration system for performing the calibration is provided with a pressure detection means for detecting the output pilot pressure from the solenoid proportional valve to the spool valve; an output current control means for outputting a current to the solenoid proportional valve when calibration is performed; and a calibration means for setting the output pilot pressure from the solenoid proportional valve in the measured data when the supply flow rate corresponds to the amount of operation of the operating tool at the calibration point in the preset setting relationship as the target pilot pressure, and calibrating the corresponding data by setting the output current value from the output current control means to the solenoid proportional valve when the pilot pressure detected by the pressure detection means becomes the target pilot pressure as the output current value corresponding to the amount of operation of the operating tool at the calibration point. [Effects of the Invention]

[0006] Claim 1 By incorporating this invention, high-precision calibration can be performed efficiently and easily, and a control valve with a special structure for calibration is not required, thus contributing to the suppression of cost increases. [Brief explanation of the drawing]

[0007] [Figure 1] This is a hydraulic circuit diagram showing a part of the hydraulic system of a work machine. [Figure 2] This figure shows the relationship between the output pilot pressure from the solenoid proportional valve and the opening area of ​​the supply opening of the spool valve. [Figure 3] This is a flowchart illustrating the calibration procedure. [Figure 4] Tables and diagrams illustrating specific examples of each data point. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows a part of a hydraulic system installed in a work machine such as a hydraulic excavator. In Figure 1, 1 is an on-board controller (corresponding to the control means of the present invention), 2 is a hydraulic pump, 3 is a solenoid proportional valve for the pump that operates based on a control signal from the controller 1 to vary the capacity of the hydraulic pump 2, 4 is an oil tank, 5 is a hydraulic actuator that uses the hydraulic pump 2 as a hydraulic power source, 6 is a control valve that controls the supply and discharge of the hydraulic actuator 5 based on a control signal from the controller 1, and 7 is an operating device (such as an operating lever or pedal) that is operated to drive the hydraulic actuator 5. In this embodiment, the hydraulic actuator 5 is a bidirectional rotating motor or a double-acting cylinder, with pressurized oil supplied in both directions. By operating the operating tool 7 to one side, pressurized oil is supplied in one direction, and by operating it to the other side, pressurized oil is supplied in the other direction. Furthermore, for example, if the work machine is a hydraulic excavator, the hydraulic excavator is equipped with various hydraulic actuators such as a boom cylinder, stick cylinder, bucket cylinder, travel motor, swing motor, and hydraulic actuator for optional attachments, as well as control valves and operating tools for each hydraulic actuator. However, Figure 1 shows only one hydraulic actuator 5, control valve 6, and operating tool 7 that are the subject of the present invention.

[0009] The control valve 6 comprises a pilot-operated spool valve 8 (described later), a pressure compensation valve 9 located upstream of the spool valve 8, and first and second solenoid proportional valves 10A and 10B that output pilot pressure to the spool valve 8. The spool valve 8 is a directional control valve that controls the supply and discharge flow rates to the hydraulic actuator 5 and switches the direction of supply and discharge. It comprises first and second pilot ports 8a and 8b connected to first and second solenoid proportional valves 10A and 10B, respectively; a pump port 8p connected to the hydraulic pump 2 via a pressure compensation valve 9; a tank port 8t connected to the oil tank 4; a first actuator port 8c connected to the first input / output port 5a of the hydraulic actuator 5; a second actuator port 8d connected to the second input / output port 5b of the hydraulic actuator 5; and a load pressure output port 8e connected to the second pilot port 9b of the pressure compensation valve 9, which will be described later, via a load pressure introduction oil passage 11. Furthermore, when no pilot pressure is input to the first and second pilot ports 8a and 8b, the spool valve 8 is in a neutral position N, which does not perform supply and discharge control to the hydraulic actuator 5 and closes the load pressure output port 8e. However, when pilot pressure is input to the first pilot port 8a, it switches to the first operating position X, opening the supply opening 8f from the pump port 8p to the first actuator port 8c, the discharge opening 8g from the second actuator port 8d to the tank port 8t, and the load pressure opening 8h from the downstream side of the supply opening 8f to the load pressure output port 8e. Additionally, when pilot pressure is input to the second pilot port 8b, it switches to the second operating position Y, opening the supply opening 8f from the pump port 8p to the second actuator port 8d, the discharge opening 8g from the first actuator port 8c to the tank port 8t, and the load pressure opening 8h from the downstream side of the supply opening 8f to the load pressure output port 8e. Furthermore, the opening area of ​​the supply opening 8f is determined according to the pilot pressure output from the first and second electromagnetic proportional valves 10A and 10B, as shown in the opening area characteristic diagram in Figure 2, and the supply flow rate to the hydraulic actuator 5 is controlled by the opening area of ​​the supply opening 8f. In addition, when the spool valve 8 is in the first and second operating positions X and Y, the load pressure opening 8h opens, allowing the outlet pressure of the spool valve 8 (the load pressure of the hydraulic actuator 5) to be introduced into the load pressure introduction oil passage 11.

[0010] Furthermore, the pressure compensation valve 9 includes a first pilot port 9a into which the inlet pressure of the spool valve 8 is input, a second pilot port 9b into which the outlet pressure of the spool valve 8 is input via the load pressure introduction oil passage 11, and a spring 9c. The inlet pressure of the spool valve 8 input to the first pilot port 9a presses the valve body of the pressure compensation valve 9 to the closed side, and the outlet pressure of the spool valve 8 input to the second pilot port 9b and the pressing force of the spring 9c press the valve body of the pressure compensation valve 9 to the open side. The opening area of ​​the pressure compensation valve 9 is controlled so that the differential pressure (front-to-back differential pressure) between the inlet pressure and the outlet pressure of the spool valve 8 remains constant. In other words, when the differential pressure across the spool valve 8 is greater than the pressing force of the spring 9c, the valve body of the pressure compensation valve 9 moves to the closed side, reducing the opening area and increasing the passing pressure loss, which lowers the inlet pressure of the spool valve 8. On the other hand, when the differential pressure across the spool valve 8 is less than the pressing force of the spring 9c, the valve body of the pressure compensation valve 9 moves to the open side, increasing the opening area and reducing the passing pressure loss, which raises the inlet pressure of the spool valve 8. Through this operation of the pressure compensation valve 9, the differential pressure across the spool valve 8 is maintained at a constant level.

[0011] Furthermore, the first and second solenoid proportional valves 10A and 10B are operated by the output current from the controller 1 and output pilot pressure to the first and second pilot ports 8a and 8b of the spool valve 8, respectively. In this case, the first and second solenoid proportional valves 10A and 10B increase or decrease the output pilot pressure according to the output current value from the controller 1, and the output current value from the controller 1 is configured to increase or decrease according to the amount of operation of the operating tool 7, as will be described later. Furthermore, measuring adapters (not shown) can be detachably attached to the output ports of the first and second electromagnetic proportional valves 10A and 10B. By connecting a pressure sensor (corresponding to the pressure detection means of the present invention) 12 to the measuring adapter, the output pilot pressure from the first and second electromagnetic proportional valves 10A and 10B can be detected.

[0012] Here, the flow rate supplied from the spool valve 8 to the hydraulic actuator 5 is determined by the following orifice equation (1), using the opening area of ​​the supply opening 8f of the spool valve 8, the differential pressure across the spool valve 8, and the flow coefficient. Q = C × A × √ΔP ···(1) In equation (1) above, Q is the flow rate supplied to the hydraulic actuator 5 (output flow rate from the spool valve 8), C is the flow coefficient, A is the opening area of ​​the supply opening 8f of the spool valve 8, and ΔP is the differential pressure across the spool valve 8. As mentioned above, the differential pressure ΔP across the spool valve 8 is kept constant by the pressure compensation valve 9, and the opening area A of the supply opening 8f is determined according to the pilot pressure output from the first and second solenoid proportional valves 10A and 10B. Therefore, assuming the flow coefficient C is constant, the supply flow rate to the hydraulic actuator 5 will be determined according to the pilot pressure output from the first and second solenoid proportional valves 10A and 10B, even if the pump pressure of the hydraulic pump 2 or the load of the hydraulic actuator 5 fluctuates.

[0013] On the other hand, the controller 1 has an operation detection means 13 for detecting the operating direction and amount of the operating tool 7, and the pressure sensor 12 (when calibration is performed) connected to its input side, while the pump's solenoid proportional valve 3 and the first and second solenoid proportional valves 10A and 10B are connected to its output side. During normal operation when calibration, which will be described later, is not being performed, the controller 1 outputs a current as a control signal to the first and second solenoid proportional valves 10A and 10B based on the operating direction and amount of the operating tool 7 input from the operation detection means 13. In this configuration, when the operating tool 7 is operated to one side, a current is output to the first electromagnetic proportional valve 10A, and when it is operated to the other side, a current is output to the second electromagnetic proportional valve 10B. The controller 1 stores first and second correspondence data CD1 and CD2, which show the correspondence between the amount of operation of the operating tool 7 to one side and the other side and the output current values ​​to the first and second electromagnetic proportional valves 10A and 10B. Based on these first and second correspondence data CD1 and CD2, the controller 1 is configured to output current values ​​to the first and second electromagnetic proportional valves 10A and 10B that increase or decrease in accordance with the increase or decrease in the amount of operation of the operating tool. As described above, the first and second electromagnetic proportional valves 10A and 10B output a pilot pressure to the spool valve 8 that increases or decreases in accordance with the output current value from the controller 1. As a result, the spool valve 8 moves with a stroke corresponding to the pilot pressure, opening the supply opening 8f and the discharge opening 8g, thereby controlling the supply flow rate and discharge flow rate to the hydraulic actuator 5. Furthermore, during the calibration described later, current is output from the controller 1 to the first and second electromagnetic proportional valves 10A and 10B even when the operating tool 7 is not being operated. The controller 1 also outputs a current value to the pump electromagnetic proportional valve 3 that increases or decreases according to the amount of operation of the operating tool 7, thereby controlling the discharge flow rate of the hydraulic pump 2 to increase or decrease in accordance with the increase or decrease in the amount of operation of the operating tool. However, the explanation of the control of the pump electromagnetic proportional valve 3 will be omitted.

[0014] Furthermore, a monitoring device 15 is connected to the controller 1 so that it can be freely input and output. The monitoring device 15 is, for example, located in the operator's cab of a work machine and is equipped with a display screen (not shown), a keyboard, a touch panel, a dial, and other operating means, and is used for various displays and settings, but in this embodiment, the operating means of the monitoring device 15 can be used to start, perform, and end calibration.

[0015] Furthermore, the controller 1 is provided with a calibration control unit 16 that controls calibration to set the correspondence between the amount of operation of the operating tool 7 and the flow rate supplied to the hydraulic actuator 5 (output flow rate from the control valve 6) to a preset relationship. The calibration control unit 16 is provided with an output current control unit (corresponding to the output current control means of the present invention) 16a that outputs current to the first and second electromagnetic proportional valves 10A and 10B based on the operation of the monitoring device 15 when calibration is performed, and a calibration control unit (corresponding to the calibration means of the present invention) 16b that calibrates the first and second corresponding data CD1 and CD2.

[0016] Furthermore, the calibration control unit 16 stores first and second setting data SD1 and SD2, which show the setting relationship between the amount of operation on one side and the other side of the pre-set operating tool 7 and the flow rate supplied to the hydraulic actuator 5. In this case, if the setting relationship is the same whether the operating tool 7 is operated on one side or the other side, the first and second setting data SD1 and SD2 will be the same.

[0017] Furthermore, before the calibration is executed, the calibration control unit 16 receives, using the monitor device 15 or via other input means or communication means, first and second measured data AD1 and AD2 indicating the correspondence between the pilot pressure output from the first and second electromagnetic proportional valves 10A and 10B to the spool valve 8 and the output flow rate output from the first and second actuator ports 8c and 8d of the spool valve 8, which are the data actually measured at the stage before mounting the control valve 6 on the working machine. The first and second measured data AD1 and AD2 are created based on, for example, the measurement results obtained in the pre-shipment inspection of the control valve 6 on the supplier side of the control valve 6.

[0018] Furthermore, before the calibration is executed, a pressure sensor 12 is connected to the output ports of the first and second electromagnetic proportional valves 10A and 10B via a measurement adapter, and the pressure sensor 12 and the controller 1 are connected so that the detection signal from the pressure sensor 12 is input to the calibration control unit 16.

[0019] Then, the calibration control unit 16 controls the calibration to make the correspondence between the operation amount of the operating tool 7 and the supply flow rate to the hydraulic actuator 5 (the output flow rate from the control valve 6) conform to a preset relationship based on the first and second set data SD1 and SD2 and the first and second measured data AD1 and AD2. The calibration control will be described based on the flowchart in FIG. 3. Note that the calibration control when the operating tool 7 is operated on one side and when it is operated on the other side is the same, so hereinafter, the case where the operating tool 7 is operated on one side will be taken as an example for explanation.

[0020] First, when an operation signal for starting the calibration operation is input from the monitor device 15 to the calibration control unit 16, the calibration points of the operating tool operation amount (for example, operation amounts of 50%, 80%, 100%, etc.) are set (step S1). The calibration points of the operation amount can be arbitrarily set and changed by the monitor device 15. Next, based on the first setting data SD1, the supply flow rate corresponding to the operation amount of the calibration point in the preset setting relationship is determined, and this supply flow rate is set as the set supply flow rate of the calibration point (step S2). Next, based on the first measured data AD1, the measured value of the output pilot pressure from the first solenoid proportional valve 10A when the supply flow rate becomes the set supply flow rate for the calibration point is determined, and this output pilot pressure is set as the target pilot pressure for the calibration point (step S3). The amount of operation of the calibration point tool, the set supply flow rate, and the target pilot pressure set in steps S1 to S3 are displayed on the monitoring device 15. Next, based on the operation of the monitoring device 15, the output current control unit 16a outputs current to the first electromagnetic proportional valve 10A. Then, while monitoring the output pilot pressure from the first electromagnetic proportional valve 10A detected by the pressure sensor 12, the output current value to the first electromagnetic proportional valve 10A is adjusted so that the output pilot pressure becomes the target pilot pressure of the calibration point (step S4). This adjustment of the output current value continues until the output pilot pressure detected by the pressure sensor 12 falls within the set range of the target pilot pressure (steps S4, S5). Then, when the output pilot pressure detected by the pressure sensor 12 falls within the set range of the target pilot pressure, the calibration control unit 16b calibrates the first corresponding data CD1 stored in the controller 1 as a calibrated output current value corresponding to the amount of operation of the calibration point's operating tool, using the output current value to the first electromagnetic proportional valve 10A when the target pilot pressure falls within the set range (step S6). In this case, if there is only one calibration point to perform the calibration, the calibration control unit 16b further uses the difference between the calibrated output current value and the output current value of the calibration point in the first corresponding data CD1 stored in the controller 1 as the calibration amount, and calibrates the correspondence between the operating amount of the operating tool in the first corresponding data CD1 and the output current value to the first electromagnetic proportional valve 10A over the entire range of the operating amount of the operating tool, thereby completing the calibration. Furthermore, if there are multiple calibration points, although not shown in the flowchart of Figure 3, after performing steps S1 to S5 for each calibration point, the calibration is completed by using the calibrated output current values ​​at the multiple calibration points to calibrate the correspondence between the operating amount of the operating tool in the first corresponding data CD1 and the output current value to the first electromagnetic proportional valve 10A over the entire range of the operating amount of the operating tool. Furthermore, calibration is also performed in a similar manner to calibrate the correspondence between the amount of operation of the operating tool in the second corresponding data CD2 and the output current value to the second solenoid proportional valve 10B. After the calibration is completed, when the operating tool 7 is operated during normal operation, the current output to the first and second solenoid proportional valves 10A and 10B is performed using the calibrated first and second corresponding data CD1 and CD2. As a result, the relationship between the amount of operation of the operating tool and the supply flow rate to the hydraulic actuator 5 is controlled to conform to the aforementioned set relationship (the relationship set in the first and second setting data). Figure 4 shows an example of specific numerical values ​​for the corresponding data CD (first or second corresponding data CD1, CD2), setting data SD (first or second setting data SD1, SD2), measured data AD (first or second measured data AD1, AD2), the output current value calibrated in the calibration, and the configured corresponding data CD (first or second corresponding data CD1, CD2).

[0021] In this embodiment configured as described, the hydraulic system of the work machine includes a hydraulic actuator 5, a control valve 6 that controls the flow rate supplied to the hydraulic actuator 5, an operating tool 7 that is operated to drive the hydraulic actuator 5, and a controller 1 that controls the control valve 6 based on the operation of the operating tool 7. In this system, when performing calibration to set the correspondence between the amount of operation of the operating tool 7 and the flow rate supplied to the hydraulic actuator 5 to a preset relationship, the control valve 6 controls the hydraulic actuator with an opening area corresponding to the input pilot pressure. The control valve 6 is configured with a spool valve 8 that opens an opening 8f for supplying power to the inverter 5, a pressure compensation valve 9 that maintains a constant differential pressure across the supply opening 8f of the spool valve 8, and electromagnetic proportional valves 10 (first and second electromagnetic proportional valves 10A and 10B) that output pilot pressure to the spool valve 8 according to the current value output from the controller 1. Meanwhile, the controller 1 is equipped with correspondence data CDs (first and second correspondence data CD1 and CD2) between the amount of operation of the operating tool and the output current value to the electromagnetic proportional valve 10, and controls the control valve 6 by outputting a current value corresponding to the amount of operation of the operating tool to the electromagnetic proportional valve 10 based on the correspondence data CDs. Furthermore, the system is configured to perform calibration using measured data AD (first and second measured data AD1 and AD2) obtained by actually measuring the relationship between the output pilot pressure from the electromagnetic proportional valve 10 and the supply flow rate output from the control valve 6 before the control valve 6 is mounted on the work machine. The calibration system for performing this calibration includes a pressure sensor 12 that detects the output pilot pressure from the electromagnetic proportional valve 10 to the spool valve 8, an output current control unit 16a that outputs current to the electromagnetic proportional valve 10 when calibration is performed, and a calibration control unit 16b that uses the output pilot pressure from the electromagnetic proportional valve 10 in the measured data AD when the supply flow rate corresponds to the amount of operation of the operating tool at the calibration point in a preset relationship as the target pilot pressure, and uses the output current value from the output current control unit 16a to the electromagnetic proportional valve 10 when the pilot pressure detected by the pressure sensor 12 becomes the target pilot pressure as the output current value corresponding to the amount of operation of the operating tool at the calibration point to calibrate the corresponding data CD.

[0022] In this embodiment, by using the measured data AD, which is obtained by actually measuring the relationship between the output pilot pressure from the electromagnetic proportional valve 10 and the supply flow rate output from the control valve 6, the corresponding data CD between the operating amount of the operating tool and the output current value to the electromagnetic proportional valve 10 can be calibrated to a preset relationship. However, since the measured data AD is obtained before the control valve 6 is mounted on the work machine, the calibration can be greatly improved in efficiency without requiring the time and effort of connecting a flow meter to the control valve mounted on each work machine, as would be required when measuring after the control valve 6 is mounted on the work machine. Furthermore, a control valve with a special structure for calibration is not required, which contributes to suppressing cost increases. Moreover, in this case, the control valve 6 is equipped with a pressure compensation valve 9 that maintains a constant differential pressure across the spool valve 8, which has an opening 8f for supplying fluid to the hydraulic actuator 5. Therefore, the control valve 6 mounted on the work machine will control the supply flow rate to the hydraulic actuator 5 with the same correspondence as the measured data AD measured before the control valve 6 was mounted on the work machine, regardless of fluctuations in the load pressure of the hydraulic actuator 5 or the discharge pressure of the hydraulic pump 2. As a result, highly accurate calibration can be performed even when using the measured data AD measured before the control valve 6 was mounted on the work machine.

[0023] It should be noted that the present invention is not limited to the above embodiments, and some of the control performed by the calibration control unit 16 in the above embodiments can be performed by an operator. For example, in the above embodiments, measured data is input to the calibration control unit 16, and the calibration control unit 16 automatically sets the target pilot pressure based on the measured data, but it is also possible to configure the system so that an operator sets the target pilot pressure based on the measured data. However, even if some of the control performed by the calibration control unit 16 is performed by an operator, the calibration of the corresponding data is performed by the calibration control unit (calibration means of the present invention) 16b.

[0024] Furthermore, in the above embodiment, the output current control unit (output current control means) 16a and the calibration control unit (calibration means) 16b are provided in the in-vehicle controller (control means) 1. However, these output current control unit 16a and calibration control unit 16b can also be provided in an external controller that is detachably connected to the in-vehicle controller 1, and the external controller can be connected to the in-vehicle controller when calibration is performed.

[0025] Furthermore, in the above embodiment, the measured data used for calibration is the correspondence between the output pilot pressure from the electromagnetic proportional valve and the supply flow rate output from the control valve, measured before the control valve is mounted on the work machine. However, the system is not limited to this, and it is also possible to use measured data that is the correspondence between the input current value to the electromagnetic proportional valve and the supply flow rate output from the control valve, measured before the control valve is mounted on the work machine. In this case, the measured data is also created, for example, by the control valve supplier based on the measurement results performed during the pre-shipment inspection of the control valve. Furthermore, when performing calibration using measured data obtained by actually measuring the correspondence between the input current value to the solenoid proportional valve and the supply flow rate output from the control valve, the calibration system is provided with an output current control means that outputs current to the solenoid proportional valve when calibration is performed, and a calibration means that calibrates the corresponding data by setting the input current value to the solenoid proportional valve in the measured data when the supply flow rate corresponds to a setting relationship predetermined to the operating amount of the calibration point's operating tool as the output current value corresponding to the operating amount of the calibration point's operating tool. Thus, when calibration is performed using measured data obtained by actually measuring the relationship between the input current value to the electromagnetic proportional valve and the supply flow rate output from the control valve before the control valve is mounted on the work machine, it is not necessary to detect the pilot pressure as in the above embodiment, and high-precision calibration can be performed more easily. Furthermore, in this case, if the measured data is input into a two-dimensional code or stored on a server, calibration can be performed even more easily by reading the two-dimensional code or communicating with the server. [Industrial applicability]

[0026] This invention can be used to calibrate the relationship between the amount of operation of an operating tool and the flow rate supplied to a hydraulic actuator in a hydraulic system of a work machine such as a hydraulic excavator. [Explanation of Symbols]

[0027] 1 Controller 5. Hydraulic Actuator 6. Control valve 7 Operating Tools 8 Spool valve 8f Spool valve supply opening 9. Pressure Compensation Valve 10A, 10B First and Second Solenoid Proportional Valves 12 Pressure Sensor 13 Operation detection means 15. Monitoring device 16a Output current control unit 16b Configuration Control Unit

Claims

[Claim 1] In a hydraulic system for a work machine comprising a hydraulic actuator, a control valve for controlling the flow rate supplied to the hydraulic actuator, an operating tool for driving the hydraulic actuator, and control means for controlling the control valve based on the operation of the operating tool, when performing calibration to set the correspondence between the amount of operation of the operating tool and the flow rate supplied to the hydraulic actuator to a preset relationship, The control valve comprises a spool valve that opens a supply opening to a hydraulic actuator with an opening area corresponding to the input pilot pressure, a pressure compensation valve that maintains a constant differential pressure across the supply opening of the spool valve, and an electromagnetic proportional valve that outputs a pilot pressure to the spool valve corresponding to the current value output from the control means. The control means includes correspondence data between the amount of operation of the operating tool and the output current value to the electromagnetic proportional valve, and controls the control valve by outputting a current value corresponding to the amount of operation of the operating tool to the electromagnetic proportional valve based on this correspondence data, The configuration is such that calibration is performed using measured data to determine the correspondence between the output pilot pressure from the electromagnetic proportional valve and the supply flow rate output from the control valve, before the control valve is mounted on the work machine. The calibration system that performs the calibration, A pressure detection means for detecting the output pilot pressure from the solenoid proportional valve to the spool valve, An output current control means that outputs current to the electromagnetic proportional valve when calibration is performed, A calibration system for a hydraulic system, characterized by comprising: a calibration means that sets the output pilot pressure from the electromagnetic proportional valve in the measured data when the supply flow rate corresponds to the amount of operation of the calibration point's operating tool according to the preset setting relationship, as the target pilot pressure, and the output current value from the output current control means to the electromagnetic proportional valve when the pilot pressure detected by the pressure detection means becomes the target pilot pressure, as the output current value corresponding to the amount of operation of the calibration point's operating tool, thereby calibrating the corresponding data.

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