JP2022024770A - Construction machine - Google Patents

Abstract

To provide a construction machine allowing good workability to be achieved by suppressing a variation in flow control property caused by individual difference between double tilting pumps.SOLUTION: A controller 6 updates a control map of a double tilting pump 2 with a first update map 19 by: outputting a closing signal to a changeover valve 5; outputting an open signal to an unload valve 12; acquiring a detected value of a tilting angle sensor 14 while changing a tilting angle control signal in accordance with a specific pattern; and generating the first update map 1 corresponding to the detected value and the tilting angle control signal upon input of a signal from a newly mounted switch 15.SELECTED DRAWING: Figure 2

Description

The present invention relates to a calibration technique for a hydraulic pump mounted on a construction machine such as a hydraulic excavator.

In recent years, energy saving has become an important development item in construction machinery such as hydraulic excavators and wheel loaders. It is important to improve the efficiency of the hydraulic system itself in order to save energy in construction machinery, and the application of a hydraulic closed circuit system that directly controls by connecting a hydraulic actuator to a closed circuit by a hydraulic pump is being studied. In this system, there is no pressure loss due to the control valve, and only the required flow rate is discharged by the double tilt pump for the closed circuit, so the flow rate loss is small. It is also possible to regenerate the potential energy of the actuator and the energy during deceleration. Therefore, high efficiency can be achieved.

As a known technique for hydraulic pumps of construction machinery, Patent Document 1 calibrates the maximum discharge flow rate at the maximum load of the hydraulic pump in order to suppress variations in the maximum working amount of construction machinery, and reduces variations due to individual differences. Is described.

Japanese Unexamined Patent Publication No. 2013-40487

In the hydraulic circuit of a construction machine described in Patent Document 1, a hydraulic pump discharges a constant hydraulic oil, and a control valve adjusts the inflow flow rate to the cylinder to adjust the working speed of the construction machine. In order to suppress engine stall that occurs while working at the maximum load, the hydraulic pump has its own discharge flow rate so that the torque (absorption torque) acting on the drive shaft of the hydraulic pump does not increase more than a certain amount according to the discharge pressure. It is equipped with a mechanism to adjust. Since this adjustment mechanism varies depending on the individual difference of the hydraulic pump, the amount of work at the maximum load varies depending on the construction machine. Therefore, it is equipped with a calibration means that learns the absorption torque correction value according to the engine speed and reflects it in the control current command value.

However, in the hydraulic closed circuit system, the inflow rate to the cylinder is controlled by the double tilt pump, so not only the work amount at the maximum load but also all the work speeds from fine operation to the maximum load are controlled by the double tilt pump. It will be decided. Therefore, if not only the variation of the pump discharge flow rate at the maximum load but also the variation is not suppressed in all the flow rate regions, there is a problem that the behavior of the construction machine with respect to the operation of the operator varies, resulting in a decrease in workability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a construction machine capable of obtaining good workability by suppressing variation in flow rate controllability due to individual differences of both tilting pumps. There is something in it.

In order to achieve the above object, the present invention has a first flow path connecting a bi-tilt pump, a hydraulic actuator, a first intake / discharge port of the bi-tilt pump, and a first oil chamber of the hydraulic actuator. A second flow path connecting the second suction / discharge port of the double tilt pump and the second oil chamber of the hydraulic actuator, and a switching valve capable of opening and closing the first flow path and the second flow path. , The regulator that controls the tilt angle of the double tilt pump, the operation lever for instructing the operation of the hydraulic actuator, and the switching valve are controlled to open and close according to the operation signal input from the operation lever. The target tilt angle of the double tilt pump is determined based on the operation signal, and the target tilt is based on a control map in which the target tilt angle and the tilt angle control signal output to the regulator are associated with each other. In a construction machine provided with a controller that converts an angle into the tilt angle control signal and outputs the tilt angle control signal to the regulator, the first suction / discharge port and the second suction / discharge port are connected to each other. A communication flow path, an unload valve provided in the communication flow path that changes the opening degree according to a control signal from the controller, and a tilt angle sensor that detects the tilt angle of the double tilt pump. The controller includes a newly mounted switch that is operated when the double tilt pump is newly mounted, and the controller outputs an open signal to the switching valve when a signal is input from the newly mounted switch, and the unload valve. A first, in which an open signal is output, the tilt angle control signal is changed according to a predetermined pattern, the detection value of the tilt angle sensor is acquired, and the detected value and the tilt angle control signal are associated with each other. It is assumed that an update map is generated and the control map is updated with the first update map.

According to the present invention configured as described above, the relationship between the target tilt angle and the tilt angle of the bi-tilt pump is calibrated, and the variation in the flow rate controllability due to the individual difference of the bi-tilt pump is suppressed. , Good workability can be obtained.

According to the construction machine according to the present invention, good workability can be obtained by suppressing the variation in the flow rate controllability due to the individual difference of the bi-tilt pump.

It is a side view which shows the hydraulic excavator which concerns on 1st Embodiment of this invention. It is a schematic diagram of the hydraulic drive device in 1st Embodiment of this invention. It is a functional block diagram of the controller in 1st or 3rd Embodiment of this invention. It is a flowchart which shows an example of the processing of the controller which concerns on the control of a bi-tilt pump in 1st Embodiment of this invention. It is a figure which shows an example of the change of the tilt angle control signal and the detection value of the tilt angle sensor at the time of calibration of the bi-tilt pump in the 1st Embodiment of this invention. It is a figure which shows an example of the control map generated at the time of calibration of the bi-tilt pump in the 1st Example of this invention. It is a schematic diagram of the hydraulic drive device in the 2nd Embodiment of this invention. It is a functional block diagram of the controller in the 2nd Embodiment of this invention. An example of a change in the tilt angle control signal, the detection value of the tilt angle sensor, the control signal of the unload valve, and the differential pressure detected by the pressure sensor during calibration of the double tilt pump in the second embodiment of the present invention. It is a figure which shows. It is a figure which shows an example of the control map generated at the time of calibration of the bi-tilt pump in the 2nd Example of this invention. It is a functional block diagram of the controller in the 3rd Embodiment of this invention. It is a functional block diagram of the controller in 4th Embodiment of this invention. It is a functional block diagram of the controller in 5th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a large hydraulic excavator as an example of a construction machine. It should be noted that the present invention can be applied to all construction machines provided with a plurality of hydraulic closed circuits in which both tilting pumps and hydraulic actuators are connected in a closed circuit shape via a switching valve, and the subject of the present invention is It is not limited to hydraulic excavators.

FIG. 1 is a side view showing a hydraulic excavator according to the first embodiment of the present invention.

(Hydraulic excavator)
In FIG. 1, the hydraulic excavator 100 is mounted on a lower traveling body 102 equipped with a crawler-type traveling device driven by a traveling motor 101 so as to be swivelable on the lower traveling body 102, and is driven by a swivel motor 103. A swivel body 104 and a working device 105 rotatably attached to the front portion of the upper swivel body 104 in the vertical direction are provided. A cab 106 on which the operator is boarded is provided on the upper swivel body 104.

The working device 105 includes a boom 107 rotatably attached to the front portion of the upper swivel body 104 and an arm as a working member rotatably connected to the tip portion of the boom 107 in the vertical or longitudinal direction. 108, a bucket 109 as a working member rotatably connected to the tip of the arm 108 in the vertical or front-back direction, a boom cylinder 4 which is a hydraulic actuator for driving the boom 107, and a hydraulic actuator for driving the arm 108. The arm cylinder 110 is provided with a bucket cylinder 111, which is a hydraulic actuator for driving the bucket 109.

(Hydraulic drive)
FIG. 2 is a schematic view showing an example of a hydraulic drive device mounted on the hydraulic excavator 100. In FIG. 2, the hydraulic drive device 200 drives the boom cylinder 4, which is a hydraulic actuator, in a closed circuit. In FIG. 2, the parts related to the drive of the hydraulic actuator other than the boom cylinder 4 are omitted.

(engine)
The engine 1 is connected to the controller 6 via a signal line. The rotation speed of the engine 1 is controlled by the controller 6. The target rotation speed of the engine 1 is set by the engine control dial 18. The engine control dial 18 is located in the cab 106 and is operated by an operator.

(Both tilt pump)
The bi-tilt pump 2 is driven by receiving power from the engine 1. The double tilting pump 2 has a tilting swash plate mechanism having a pair of suction and discharge ports 2a and 2b, and a regulator 3 that adjusts the angle (tilt angle) of the swash plate to adjust the discharge flow rate (pushing volume) per rotation. Is equipped with. The regulator 3 controls the discharge direction and the discharge flow rate of the bi-tilt pump 2 according to the control signal received from the controller 6 via the control signal line.

(Switching valve)
The two suction / discharge ports 2a and 2b of the bi-tilt pump 2 are connected to the switching valve 5 via the flow paths 30 and 31. The switching valve 5 is connected to the boom cylinder 4 via the flow paths 32 and 33. The switching valve 5 is controlled to open and close by a control signal received from the controller 6, and switches the flow paths 30 and 32 and the flow paths 31 and 33 into a flow state or a cutoff state. When the switching valve 5 is in the open state, one suction / discharge port 2a of the double tilt pump 2 communicates with the bottom side oil chamber 4a of the boom cylinder 4 via the flow paths 30 and 32, and the other suction / discharge port 2b. Communicates with the rod side oil chamber 4b of the boom cylinder 4 via the flow paths 31 and 33. As a result, the bi-tilt pump 2 and the boom cylinder 4 are connected in a closed circuit manner.

(controller)
The controller 6 includes an input / output interface for inputting / outputting signals to and from each device, and an arithmetic unit composed of a central processing unit (CPU) and peripheral circuits thereof, and performing various arithmetic according to a predetermined program. It is connected to the operation lever 7 that gives a drive instruction of the boom cylinder 4 by a signal line, and is connected to the regulator 3 and the switching valve 5 by a control signal line. The controller 6 has a learning command generation unit 6a, an unload valve control unit 6b, a control map generation unit 6c, a pump control unit 6d, a switching valve control unit 6e, and an engine control unit when the arithmetic unit executes a predetermined program. Realize each function of 6f.

The switching valve control unit 6e determines the connection between the bi-tilt pump 2 and the hydraulic actuator 4 based on the operation amount of the operating lever 7. For example, when the operating lever 7 is operated, the switching valve control unit 6e outputs an open signal to the switching valve 5 and connects the bi-tilt pump 2 to the hydraulic actuator 4.

The pump control unit 6d sets the target tilt angle of the bi-tilt pump 2 to a value corresponding to the operation amount of the operating lever 7, and sets the discharge direction of the bi-tilt pump 2 to a direction corresponding to the operation direction of the operation lever 7. Set to. The pump control unit 6d outputs a tilt angle control signal to the regulator 3 based on the target tilt angle, and controls the discharge flow rate and the discharge direction of both tilt pumps 2.

The engine control unit 6f calculates a target rotation speed based on the operation amount of the engine control dial 18, and transmits a rotation speed control command to the engine 1.

Details of the learning command generation unit 6a, the unload valve control unit 6b, and the control map generation unit 6c will be described later.

(others)
The flow paths 32 and 33 connected to the boom cylinder 4 are connected to the tank 9 via the flushing valve 8. The flushing valve 8 communicates the low pressure side of the flow paths 32 and 33 with the tank 9 to eliminate excess or deficiency of hydraulic oil in the closed circuit. The flow paths 30 and 31 connected to the bi-tilt pump 2 are connected to the charge flow path 22 via the relief valves 10a and 10b and the check valves 23a and 23b. The charge flow path 22 is connected to the charge hydraulic source 21. The relief valves 10a and 10b open when the discharge pressure of the double tilt pump 2 reaches a certain high pressure or higher, and discharge the high pressure hydraulic oil discharged from the double tilt pump 2 to the charge flow path 22. That is, the relief valves 10a and 10b have a function as a safety valve. The check valves 23a and 23b replenish the insufficient flow rate on the suction side of the suction / discharge ports 2a and 2b from the charge flow path 22.

(Structure relating to the present invention)
Next, the configuration related to the present invention in the present embodiment will be described.

(Tilt angle sensor)
The bi-tilt pump 2 is provided with a tilt angle sensor 14 for measuring the angle (tilt angle) of the swash plate. The tilt angle sensor 14 is connected to the controller 6 via a signal line. The tilt angle sensor 14 outputs a signal corresponding to the tilt angle to the controller 6.

(Unload valve)
The flow paths 30 and 32 connected to the bi-tilt pump 2 are connected via the communication flow path 34. An unload valve 12 is provided in the communication flow path 34. The unload valve 12 is connected to the controller 6 via a signal line, and changes the opening degree according to a control signal from the controller 6.

(Switches, displays)
A newly mounted switch 15, a maintenance switch 16, and a display 17 are connected to the controller 6 via a signal line. The newly mounted switch 15, the maintenance switch 16, and the display 17 are located in the cab 106 and are operated by the operator. The newly mounted switch 15 is a switch that is operated when the construction machine is shipped. The maintenance switch 16 is a switch that is operated when the bi-tilt pump 2 is replaced, for example, at the end of its life. The display 17 displays the information received from the controller 6.

(controller)
FIG. 3 is a functional block diagram of the controller 6. The controller 6 includes a learning command generation unit 6a, an unload valve control unit 6b, a control map generation unit 6c, a pump control unit 6d, a switching valve control unit 6e, and an engine control unit 6f.

When a signal is input from the newly mounted switch 15, the learning command generation unit 6a has a waveform of the tilt angle control signal for calibration operation of the double tilt pump 2 (see FIG. 5, hereinafter referred to as a tilt angle control signal pattern). Is called) is output to the control map generation unit 6c, the pump control unit 6d, the switching valve control unit 6e, and the unload valve control unit 6b.

When the pump control unit 6d receives the tilt angle control signal pattern, it outputs a tilt angle control signal according to the tilt angle control signal pattern to the regulator 3. When the unload valve control unit 6b receives the tilt angle control signal pattern, it outputs an open signal to the unload valve 12. When the switching valve control unit 6e receives the tilt angle control signal pattern, it outputs a closing signal to the switching valve 5.

The control map generation unit 6c acquires and stores the tilt angle control signal pattern and the detection value of the tilt angle sensor 14, and uses a control map showing the correspondence between the tilt angle control signal and the tilt angle as an update map. Generate. The control map generation unit 6c outputs the generated control map to the pump control unit 6d. The pump control unit 6d updates the control map stored by itself with the received control map.

(Pump operation during calibration)
The operation of the double tilt pump 2 at the time of calibration in this embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the processing of the controller related to the control of the bi-tilt pump. When the construction machine 100 is started, the start state S1 is set, and when the state is changed to S2, it is determined based on the signal of the newly mounted switch 15 whether or not the double tilt pump 2 is newly mounted. When the newly mounted switch 15 is valid, the state transitions to the state S3. In the state S3, the controller 6 outputs an open signal to the unload valve 12, and when the state S4 is entered, the controller 6 outputs a tilt angle control signal according to the tilt angle control signal pattern to the double tilt pump 2. The regulator 3 controls the tilt angle of the double tilt pump 2 according to the received tilt angle control signal, and discharges the hydraulic oil to the double tilt pump 2. The hydraulic oil discharged from one suction / discharge port of the bi-tilt pump 2 is sucked into the other suction / discharge port via the unload valve 12 (see FIG. 1).

At this time, in the state S5, the controller 6 acquires the detection value of the tilt angle sensor 14. FIG. 5 shows an example of changes in the tilt angle control signal and the detection value of the tilt angle sensor 14 at this time. In FIG. 5, the suction / discharge port 2a side tilt angle control signal is a discharge command to the flow path 30 (see FIG. 2), and the suction / discharge port 2b side tilt angle control signal is sent to the flow path 31 (see FIG. 2). It is a discharge command of. The tilt angle detected by the tilt angle sensor 14 is output as a value in which the discharge to the suction / discharge port 2a side is positive and the discharge to the suction / discharge port 2b side is negative.

Returning to FIG. 4 and transitioning to the state S6, the controller 6 generates the control map 19 as shown in FIG. 6 based on the waveform of FIG. 5, for example. In FIG. 6, the horizontal axis is the tilt angle control signal, and the vertical axis is the detection value of the tilt angle sensor 14. FIG. 5 shows an example in which hysteresis exists in the linear region of the control map 19 due to internal friction of the bi-tilt pump 2 and the like.

Upon transition to the state S7, it is determined whether or not the generated control map 19 is appropriate. For example, when the hysteresis is clearly large, or when the maximum tilt angle is not reached. If the control map 19 is appropriate, the state transitions to the state S8, and the control map inside the pump control unit 6d of FIG. 2 is updated with the control map 19. On the other hand, if it is determined that the control map 19 generated in the state S6 is not appropriate, the state transitions to the state S9, and the control map inside the pump control unit 6d in FIG. 2 is generated for backup based on, for example, design information. Update with the map. When the update of the control map is completed, the state transitions to the state S10, and the calibration of the bi-tilt pump 2 is completed.

(Pump operation during normal operation)
On the other hand, when it is determined that the newly mounted switch 15 is invalid in the state S2, that is, when the construction machine 100 is started normally after the second time, the state transitions to the state S11. In the state S11, the pump control unit 6d of FIG. 2 converts the target tilt angle calculated from the operation lever 7 into a tilt angle control signal by using the control map 19. At this time, the detection value of the tilt angle sensor 14 on the vertical axis of the control map 19 corresponds to the target tilt angle. Further, for example, the tilt angle control signal is calculated in consideration of the hysteresis of the control map for the increase / decrease of the target tilt angle. After calculating the tilt angle control signal, the state transitions to the state S12, and the pump control unit 6d in FIG. 2 outputs the tilt angle control signal to the regulator 3.

(effect)
In this embodiment, the first flow paths 30 and 32 connecting the bi-tilt pump 2, the hydraulic actuator 4, the first intake / discharge port 2a of the bi-tilt pump 2, and the first oil chamber 4a of the hydraulic actuator 4 are connected. The second flow paths 31 and 33 connecting the second suction / discharge port 2b of the double tilt pump 2 and the second oil chamber 4b of the hydraulic actuator 4, the first flow paths 30, 32 and the second flow path 31. , 33 is a switching valve 5 that can open and close, a regulator 3 that controls the tilt angle of the double tilt pump 2, an operation lever 7 for instructing the operation of the hydraulic actuator 4, and an operation input from the operation lever 7. The switching valve 5 is controlled to open and close based on the signal, the target tilt angle of both tilting pumps 2 is determined based on the operation signal, and the target tilt angle and the tilt angle control signal output to the regulator 3 are set. In the construction machine 100 provided with a controller that converts the target tilt angle into the tilt angle control signal based on the associated control map and outputs the tilt angle control signal to the regulator 3, the first suction / discharge is performed. An unload valve provided in the communication flow path 34 connecting the port 2a and the second intake / discharge port 2b and switched between the open position and the closed position according to the control signal from the controller 6. A tilt angle sensor 14 for detecting the tilt angle of the double tilt pump 2 and a newly mounted switch 15 operated when the double tilt pump 2 is newly mounted are provided, and the controller 6 is a newly mounted switch 15. When a signal is input from, a closed signal is output to the switching valve 5, an open signal is output to the unload valve 12, and the tilt angle control signal is changed according to a predetermined pattern of the tilt angle sensor 14. The detected value is acquired, the first update map 19 in which the detected value is associated with the tilt angle control signal is generated, and the control map is updated by the first update map 19.

According to this embodiment configured as described above, the following effects can be obtained.

Usually, it is difficult to prepare an accurate control map in advance because the bilateral tilting pump 2 has manufacturing variations. Therefore, if the bi-tilt pump 2 is controlled without the calibration of the present invention, the discharge flow rate of the bi-tilt pump 2 varies depending on the operation of the operating lever 7, and the speed of the hydraulic actuator 4 also varies. As a result, the operability of the construction machine 100 is lowered.

On the other hand, in the construction machine 100 according to the present embodiment, since the control map can be made accurate by calibrating the bi-tilt pump 2, the speed variation of the hydraulic actuator 4 with respect to the operating lever 7 is suppressed, and the construction machine 100 is suppressed. It is possible to suppress the deterioration of operability.

The second embodiment of the present invention will be described focusing on the differences from the first embodiment.

(Problems to be solved in this example)
When high pressure acts on the intake and discharge ports 2a and 2b of the double tilt pump 2, which is generally a swash plate type hydraulic pump, the internal structural parts of the pump are pushed by the high pressure hydraulic oil to the tilt angle control signal. , The actual tilt angle is reduced. This is called a control error due to the return moment. In the closed circuit of the first embodiment, when the bi-tilt pump 2 is calibrated, the hydraulic oil discharged from one of the suction / discharge ports of the bi-tilt pump 2 is directly used by the bi-tilt pump 12 via the unload valve 12. The discharge pressure remains low because it is sucked into the other suction / discharge port. However, since the double tilting pump 2 in the construction machine 100 during work discharges high-pressure hydraulic oil, a return moment is generated in the double tilting pump 2, and a control error occurs in the discharge flow rate even though the calibration is performed. May occur. Therefore, there arises a problem that the work speed varies.

(Constitution)
FIG. 7 is a schematic view of the hydraulic drive device in this embodiment. In FIG. 7, pressure sensors 13a and 13b are provided in the flow paths 30 and 31 connected to the both tilting pumps 2, respectively. The controller 6 is connected to the pressure sensors 13a and 13b by a signal line. The pressure sensors 13a and 13b output signals corresponding to the pressures of the suction and discharge ports 2a and 2b to the controller 6.

FIG. 8 is a functional block diagram of the controller 6 in this embodiment. In FIG. 8, the learning command generation unit 6a outputs the tilt angle control signal pattern twice when the newly mounted switch 15 is enabled. The control map generation unit 6c generates a control map at low pressure for the first tilt angle control signal pattern, and generates a control map at high pressure for the second tilt angle control signal pattern. The pump control unit 6d updates the current control map with the newly generated control map. During normal operation, the pump control unit 6d sets the target tilt angle to the discharge pressure of the double tilt pump 2 (differential pressure detected by the pressure sensors 13a and 13b) based on the control map at low pressure and the control map at high pressure. ) Is converted into a tilt angle control signal and output to the regulator 3.

When generating the control map at high pressure, the unload valve control unit 6b opens the unload valve 12 so that the difference between the values of the pressure sensors 13a and 13b (the discharge pressure of the double tilt pump 2) becomes constant. Control the degree. The unload valve control unit 6b calculates a control signal to the unload valve 12 using the values of the pressure sensors 13a and 13b, for example, as shown in the following equation.

Here, Pd is the target discharge pressure, and ΔP is the difference between the values of the pressure sensors 13a and 13b. I0 is a control signal when the unload valve 12 is closed. K is a coefficient, and for example, a value calculated from a simulation or an experiment based on a design value is used. Pd is set to, for example, a high pressure value (20 to 30 MPa) in the hydraulic system of a construction machine.

(motion)
FIG. 9 shows the tilt angle control signal at the time of calibration of the double tilt pump 2 in this embodiment, the detection value of the tilt angle sensor 14, the control signal of the unload valve 12, and the difference detected by the pressure sensors 13a and 13b. It is a figure which shows the change of pressure.

When the newly mounted switch 15 becomes effective, the controller 6 outputs the tilt angle control signal pattern twice to the regulator 3, as shown in FIG. The controller 6 outputs an open signal to the unload valve 12 while outputting the first tilt angle control signal pattern. At this time, the difference between the values of the pressure sensors 13a and 13b is extremely small.

After outputting the first tilt angle control signal pattern, the controller 6 outputs a closing signal to the unload valve 12 and outputs a second tilt angle control signal pattern. At this time, since the unload valve 12 is closed, the hydraulic oil discharged from the double tilt pump 2 loses a refuge, and the pressure of one of the suction / discharge ports 2a and 2b of the double tilt pump 2 is the relief valve 10a. The pressure rises to the set pressure of 10b, and one of the relief valves 10a and 10b opens. The hydraulic oil discharged from one of the suction / discharge ports 2a and 2b of the double tilt pump 2 passes through one of the charge flow path 22 and the check valves 23a and 23b, and the suction / discharge ports 2a and 2b of the double tilt pump 2 are used. Inhaled to the other side of the. Therefore, the difference between the values of the pressure sensors 13a and 13b shown in FIG. 9 is determined by the set pressure of the relief valves 10a and 10b.

Here, depending on the override characteristics of the relief valves 10a and 10b, the pressure may be larger than the set pressure of the relief valves 10a and 10b in proportion to the discharge flow rate of the double tilt pump 2. At this time, when the target discharge pressure Pd of the equation (1) is set to a value equal to the set pressure of the relief valves 10a and 10b, the unload valve is set so as to reduce the pressure increase due to the override of the relief valves 10a and 10b. The unload valve control unit 6b outputs a control signal based on the equation (1) by adjusting the opening degree of 12 so that the discharge pressure of the double tilt pump 2 matches the target discharge pressure Pd. As a result, the difference between the values of the pressure sensors 13a and 13b is maintained at the set pressure of the relief valves 10a and 10b regardless of the discharge flow rate of the bi-tilt pump 2.

The control map generation unit 6c generates the control maps 20a and 20b shown in FIG. 10 as update maps based on the two tilt angle control signal patterns and the detection values of the tilt angle sensor 14. The control map 20a is a control map (control map at low pressure) generated when the unload valve 12 is open (a state in which the discharge pressure of the double tilt pump 2 is low). The control map 20b is a control map generated when the unload valve 12 is closed (a control map generated when the discharge pressure of the double tilt pump 2 is high (control map at high pressure). The pump control unit 6d displays an internal control map. It is updated with the control maps 20a and 20b. When the newly mounted switch 15 becomes invalid, the pump control unit 6d has a control map 20a at low pressure and a control map 20b at high pressure according to the differential pressure detected by the pressure sensors 13a and 13b. By interpolating with, the target tilt angle is converted into a tilt angle control signal and output to the regulator 3.

(effect)
In this embodiment, the charge hydraulic source 21, the charge flow path 22 connected to the charge hydraulic source 21, and the first check valve 23a that allows the flow of hydraulic oil from the charge flow path 22 to the first suction / discharge port 2a. The second check valve 23b, which allows the flow of hydraulic oil from the charge flow path 22 to the second suction / discharge port 2b, and the first suction / discharge port 2a open when the pressure exceeds a predetermined pressure, and the first The first relief valve 10a that discharges the hydraulic oil discharged from the suction / discharge port 2a to the charge flow path 22 and the second suction / discharge port 2b open when the pressure exceeds a predetermined pressure, and the second suction / discharge port 2b The controller 6 includes a second relief valve 10b that discharges the hydraulic oil discharged from the charging flow path 22 to the charge flow path 22, and the controller 6 unloads after a signal is input from the newly mounted switch 15 to generate a first update map 20a. The opening degree of the valve 12 is made smaller than that at the time of generating the first update map 20a, the tilt angle control signal is changed according to the predetermined pattern, the detection value of the tilt angle sensor 14 is acquired, and the tilt angle sensor 14 is acquired. A second update map 20b in which the value of the angle control signal is associated with the detected value is generated, the control map is updated with the first update map 20a and the second update map 20b, and the newly mounted switch 15 is used. When no signal is input, the first update map 20a and the map 20a according to the differential pressure between the first suction / discharge port 2a and the second suction / discharge port 2b detected by the first pressure sensor 13a and the second pressure sensor 13b. By interpolating with the second update map 20b, the target tilt angle is converted into the tilt angle control signal.

According to the present embodiment configured as described above, the control error due to the return moment is reduced even when a high pressure is applied to the double tilting pump 2, and the flow rate control accuracy of the double tilting pump 2 is improved. It is possible to suppress a decrease in operability of 100.

Further, in the present embodiment, the opening degree of the unload valve 12 can be controlled between the open position and the closed position, and the controller 6 uses the first relief valve 10a or the first relief valve 10a or the first when the second update map 20b is generated. 2 When the relief valve 10 is opened, the differential pressure between the pressure of the first intake / discharge port 2a detected by the first pressure sensor 13a and the pressure of the second intake / discharge port 2b detected by the second pressure sensor 13b is constant. The opening degree of the unload valve 12 is controlled so as to be. As a result, when the second update map 20b (control map at high pressure) is generated, the differential pressure between the first intake / discharge port 2a and the second intake / discharge port 2b is kept constant, so that the second update map The accuracy of 20b (control map at high pressure) can be improved.

The third embodiment of the present invention will be described with a focus on the differences from the second embodiment.

(Problems to be solved in this example)
In FIG. 1, the bi-tilt pump 2 is driven by the engine 1, and the discharge flow rate of the bi-tilt pump 2 is proportional to the rotation speed of the engine 1. There is a characteristic that the return moment increases in proportion to the engine speed due to the inertial force of the internal components of the bi-tilt pump 2. Therefore, if the engine speed at the time of calibration and the engine speed at the time of actual operation are different, an error occurs in the generated control map and the operability of the construction machine is deteriorated.

(Constitution)
FIG. 11 is a functional block diagram of the controller 6 in this embodiment. In FIG. 11, the engine control unit 6f of the controller 6 acquires the value of the newly mounted switch 15, and when the newly mounted switch 15 becomes effective, the target rotation speed of the engine 1 is maximized regardless of the operation of the engine control dial 18. It has a function to set the rotation speed and output a rotation speed control command to the engine 1.

(effect)
The construction machine 100 according to the present embodiment includes an engine 1 for driving a bi-tilt pump 2 and an engine control dial 18 for setting a target rotation speed of the engine 1, and a controller 6 signals from a newly mounted switch 15. Is input, the engine 1 is controlled to have the maximum rotation speed regardless of the setting of the engine control dial 18.

According to the present embodiment configured as described above, the engine 1 is driven at the maximum rotation speed at the time of calibration of the bi-tilt pump 2 regardless of the setting of the engine control dial 18. Normally, the construction machine 100 is used in a state where the engine speed is the maximum speed. Therefore, according to the control map 19 (shown in FIG. 6) generated in the state where the engine speed is the maximum speed, the return moment is used. The error becomes small, and the deterioration of the operability of the construction machine 100 can be suppressed.

The fourth embodiment of the present invention will be described with a focus on the differences from the third embodiment.

(Problems to be solved in this example)
Since there are manufacturing variations in the double tilt pump 2, there will be an error in the control map unless calibration is performed again not only when the double tilt pump 2 is newly installed but also when the double tilt pump 2 is replaced for maintenance. Occurs.

(Constitution)
FIG. 12 is a functional block diagram of the controller 6 in this embodiment. In FIG. 12, the controller 6 is connected to the maintenance switch 16 and the display 17 via a signal line. The controller 6 further includes a display generation unit 6g. The maintenance switch 16 is operated by a maintenance worker when the bilateral tilting pump 2 is replaced. The signal of the maintenance switch 16 is input to the learning command generation unit 6a, the display generation unit 6g, and the engine control unit 6f.

When the maintenance switch 16 is enabled, the display generation unit 6g causes the display 17 to display a message to the effect that the bilateral tilting pump 2 is to be recalibrated. When the maintenance switch 16 is enabled, the learning command generation unit 6a recalibrates the bi-tilt pump 2 in the same manner as when the newly mounted switch 15 is enabled. When the maintenance switch 16 is enabled, the engine control unit 6f controls so that the rotation speed of the engine 1 becomes the maximum rotation speed, as in the process when the newly mounted switch 15 is enabled. For the recalibration of the bi-tilt pump 2 by the controller 6, any of the calibration methods of the first to third embodiments may be adopted.

(effect)
The construction machine according to this embodiment includes a maintenance switch 16 that is operated when the double tilting pump 2 is replaced, and the controller 6 inputs a signal from the newly mounted switch 15 when a signal is input from the maintenance switch 16. The double tilting pump 2 is calibrated in the same manner as in the case of the above.

According to the present embodiment configured as described above, even if the double tilting pump 2 is replaced due to maintenance, the new double tilting pump 2 is calibrated to generate a control map with good flow control accuracy. It is possible to suppress a decrease in operability of the construction machine 100.

The fifth embodiment of the present invention will be described focusing on the differences from the fourth embodiment.

(Problems to be solved in this example)
When the bi-tilt pump 2 operates for a long time, the flow rate control characteristics change from those of a new product due to wear of internal parts and the like. Therefore, an error occurs in the control map.

(Constitution)
FIG. 13 is a functional block diagram of the controller 6 in this embodiment. In FIG. 13, the controller 6 further includes an aged deterioration estimation unit 6h. The aged deterioration estimation unit 6h compares the tilt angle detected by the tilt angle sensor 14 with the target tilt angle corresponding to the tilt angle control signal in the control map, and calculates an error. This error increases as the bi-tilt pump 2 deteriorates over time.

The aged deterioration estimation unit 6h notifies the display generation unit 6g that the control map needs to be recalibrated when the error becomes larger than a certain value. The display generation unit 6g causes the display 17 to display a message indicating that recalibration is necessary. When the message indicating that recalibration is necessary is displayed on the display 17, the operator operates the maintenance switch 16 to recalibrate the bilateral tilting pump 2.

(effect)
The construction machine 100 according to the present embodiment includes a display 17 controlled by the controller 6, and the controller 6 is a target of the bi-tilt pump 2 when the signal of the newly mounted switch 15 or the maintenance switch 16 is not input. When the difference between the tilt angle and the tilt angle detected by the tilt angle sensor 14 exceeds a predetermined threshold value, a message indicating that the bi-tilt pump 2 needs to be recalibrated is displayed on the display 17.

According to the present embodiment configured as described above, when the flow rate control accuracy of the bilateral tilting pump 2 deteriorates due to aged deterioration, the operator of the construction machine notices the necessity of recalibration and controls the flow rate by recalibration. By generating an accurate control map, it is possible to suppress a decrease in operability of construction machinery.

(Others, in general)
Although the examples of the present invention have been described in detail above, the present invention is not limited to the above-mentioned examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. It is also possible to add a part of the configuration of another embodiment to the configuration of one embodiment, delete a part of the configuration of one embodiment, or replace it with a part of another embodiment. It is possible.

1 ... Engine, 2 ... Double tilt pump, 2a ... Suction / discharge port (first suction / discharge port), 2b ... Suction / discharge port (second suction / discharge port), 3 ... Regulator, 4 ... Boom cylinder (hydraulic actuator), 4a ... bottom side oil pressure chamber (first oil pressure chamber), 4b ... rod side oil pressure chamber (second oil pressure chamber), 5 ... switching valve, 6 ... controller, 6a ... learning command generation unit, 6b ... unload valve control unit, 6c ... Control map generation unit, 6d ... Pump control unit, 6e ... Switching valve control unit, 6f ... Engine control unit, 6g ... Display generation unit, 6h ... Aged deterioration estimation unit, 7 ... Operation lever, 8 ... Flushing valve, 9 ... Tank, 10a ... Relief valve (first relief valve), 10b ... Relief valve (second relief valve), 12 ... Unload valve, 13a ... Pressure sensor (first pressure sensor), 13b ... Pressure sensor (second pressure) Sensor), 14 ... Tilt angle sensor, 15 ... Newly installed switch, 16 ... Maintenance switch, 17 ... Display, 18 ... Engine control dial, 19 ... Control map (1st update map), 20a ... Control map (1st) Update map), 20b ... Control map (second update map), 21 ... Charge hydraulic source, 22 ... Charge flow path, 23a ... Check valve (first check valve), 23b ... Check valve (second check valve) , 30, 32 ... Flow path (first flow path), 31, 33 ... Flow path (second flow path), 34 ... Communication flow path, 100 ... Hydraulic excavator (construction machine), 101 ... Travel motor (hydraulic actuator) , 102 ... lower traveling body, 103 ... swivel motor (hydraulic actuator), 104 ... upper swivel body, 105 ... working device, 106 ... cab, 107 ... boom, 108 ... arm, 109 ... bucket, 110 ... arm cylinder (hydraulic actuator) ), 111 ... Bucket cylinder (hydraulic actuator), 200 ... Hydraulic drive device.

Claims (6)

With a double tilt pump,
Hydraulic actuator and
A first flow path connecting the first intake / discharge port of the bi-tilt pump and the first oil chamber of the hydraulic actuator, and
A second flow path connecting the second suction / discharge port of the double tilt pump and the second oil chamber of the hydraulic actuator, and
A switching valve that can open and close the first flow path and the second flow path,
A regulator that controls the tilt angle of the double tilt pump,
An operation lever for instructing the operation of the hydraulic actuator and
The switching valve is controlled to open and close based on the operation signal input from the operation lever, the target tilt angle of the double tilt pump is determined based on the operation signal, and the target tilt angle and the regulator are output. Construction equipped with a controller that converts the target tilt angle into the tilt angle control signal based on a control map associated with the tilt angle control signal and outputs the tilt angle control signal to the regulator. In the machine
A communication flow path connecting the first suction / discharge port and the second suction / discharge port,
An unload valve provided in the communication flow path and switched between an open position and a closed position according to a control signal from the controller.
A tilt angle sensor that detects the tilt angle of both tilt pumps,
It is equipped with a newly mounted switch that is operated when the double tilting pump is newly mounted.
When a signal is input from the newly mounted switch, the controller outputs a closed signal to the switching valve, outputs an open signal to the unload valve, and changes the tilt angle control signal according to a predetermined pattern. The detection value of the tilt angle sensor is acquired, a first update map in which the detected value is associated with the tilt angle control signal is generated, and the control map is updated with the first update map. Construction machinery characterized by doing. In the construction machine according to claim 1,
A first pressure sensor that detects the pressure of the first suction / discharge port,
A second pressure sensor that detects the pressure of the second suction / discharge port, and
Charge hydraulic source and
The charge flow path connected to the charge hydraulic source and
A first check valve that allows the flow of hydraulic oil from the charge flow path to the first intake / discharge port, and
A second check valve that allows the flow of hydraulic oil from the charge flow path to the second intake / discharge port, and
A first relief valve that opens when the pressure of the first suction / discharge port exceeds a predetermined pressure and discharges the hydraulic oil discharged from the first suction / discharge port to the charge flow path.
It is provided with a second relief valve that opens when the pressure of the second suction / discharge port exceeds a predetermined pressure and discharges the hydraulic oil discharged from the second suction / discharge port to the charge flow path.
The controller
When a signal is input from the newly mounted switch, after generating the first update map, a closing signal is output to the unload valve, and the tilt angle control signal is changed according to the predetermined pattern. The detection value of the tilt angle sensor is acquired, a second update map in which the detected value is associated with the tilt angle control signal is generated, and the first update map and the second update map are used. Update the control map
When no signal is input from the newly mounted switch, the first suction / discharge port and the second suction / discharge port detected by the first pressure sensor and the second pressure sensor are subjected to the differential pressure. By interpolating the 1-update map and the 2nd update map, the target tilt angle is converted into the tilt angle control signal.
A construction machine characterized by that. In the construction machine according to claim 2,
The unload valve has a controllable opening degree between the open position and the closed position.
When the first relief valve or the second relief valve is opened when the controller generates the second update map, the pressure of the first suction / discharge port detected by the first pressure sensor and the pressure of the first suction / discharge port are described. A construction machine characterized in that the opening degree of the unload valve is controlled so that the differential pressure from the pressure of the second intake / discharge port detected by the second pressure sensor becomes constant. In the construction machine according to claim 1,
The engine that drives the double tilt pump and
It is equipped with an engine control dial that sets the target rotation speed of the engine.
The controller is a construction machine characterized in that when a signal is input from the newly mounted switch, the engine speed is controlled to be the maximum speed regardless of the setting of the engine control dial. In the construction machine according to claim 1,
Equipped with a maintenance switch that is operated when replacing the double tilt pump.
The controller is a construction machine characterized in that when a signal is input from the maintenance switch, the bi-tilt pump is calibrated in the same manner as when a signal is input from the newly mounted switch. In the construction machine according to claim 5,
It has a display controlled by the controller.
When the difference between the target tilt angle and the tilt angle detected by the tilt angle sensor exceeds a predetermined threshold value when no signal is input from the newly mounted switch or the maintenance switch of the controller. Is a construction machine characterized in that a message indicating that the bi-tilt pump needs to be recalibrated is displayed on the display.

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