Hydraulic excavator

Abstract

To provide a hydraulic shovel which can improve calibration accuracy while reducing a calibration time.SOLUTION: A hydraulic shovel includes: multiple solenoid valves 24A, 24B to 26A, 26B that generate a pilot pressure according to drive signals and output it to pressure receiving parts on one side and the other side of the multiple control valves 19, 20, 21; and a control device 23 that stores control characteristics for each of the solenoid valves 24A, 24B to 26A, 26B, and uses the stored control characteristics to generate and output drive signals corresponding to operation signals from operation devices 16A, 16B. The control device 23 simultaneously calibrates the control characteristics of the boom raising solenoid valve 24A, the arm crowd solenoid valve 25A, and the bucket crowd solenoid valve 26A in a state where a boom cylinder 8 has reached a stroke end on the boom raising side, an arm cylinder 9 has reached a stroke end on the arm crowd side, and a bucket cylinder 10 has reached a stroke end on the bucket crowd side.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a hydraulic excavator.

Background Art

[0002] A hydraulic excavator includes a traveling body, a revolving body rotatably provided above the traveling body, and a multi-articulated working device connected to the revolving body. Further, the hydraulic excavator includes, for example, a hydraulic pump, a plurality of control valves that respectively control the flow of pressure oil from the hydraulic pump to a plurality of hydraulic actuators, an operating device that generates and outputs an operation signal (electrical signal) according to an operation by an operator, a control device that generates and outputs a drive signal (electrical signal) according to the operation signal from the operating device, and a plurality of solenoid valves that generate a pilot pressure according to the drive signal from the control device and output it to a pressure receiving portion on one side and a pressure receiving portion on the other side of the plurality of control valves.

[0003] Patent Document 1 discloses a calibration device for calibrating the above-described plurality of solenoid valves. This calibration device includes a plurality of pressure sensors that respectively detect the pilot pressures output from the plurality of solenoid valves, and an external controller. The external controller controls the above-described control device (in-vehicle controller) to sequentially output a predetermined drive signal to the plurality of solenoid valves. Specifically, a predetermined drive signal is simultaneously output to a pair of solenoid valves corresponding to one control valve. Then, a calibration amount of the input / output characteristics of each solenoid valve is calculated based on the difference between a predetermined target pilot pressure and the pilot pressure detected by each pressure sensor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, calibration is simultaneously performed on a pair of solenoid valves corresponding to one control valve. Therefore, it is possible to shorten the calibration time compared to the case where the solenoid valves are calibrated one by one. Further, since pilot pressure is simultaneously input to the pressure receiving portion on one side and the pressure receiving portion on the other side of the control valve, calibration can be performed in a state where the control valve does not substantially operate (that is, a state where the hydraulic actuator does not substantially operate).

[0006] However, in Patent Document 1, due to fluctuations in the balance between the pilot pressure input to the pressure receiving portion on one side of the control valve and the pilot pressure input to the pressure receiving portion on the other side, the control valve vibrates. Therefore, the pilot pressure detected by each pressure sensor also vibrates. As a result, the calibration accuracy decreases.

[0007] On the other hand, if the solenoid valves are calibrated one by one, the calibration time becomes long. Further, if the hydraulic actuator operates, vibration occurs and is transmitted to the control valve. Therefore, the pilot pressure detected by each pressure sensor also vibrates. Therefore, also in this case, the calibration accuracy decreases.

[0008] The present invention has been made in view of the above circumstances, and an object thereof is to provide a hydraulic excavator capable of improving calibration accuracy while shortening the calibration time.

Means for Solving the Problems

[0009] In order to achieve the above object, the present invention provides a hydraulic excavator comprising a traveling body, a revolving body rotatably provided above the traveling body, a multi-articulated working device connected to the revolving body, a plurality of hydraulic cylinders for driving the working device, a hydraulic pump, a plurality of control valves for respectively controlling the flow of pressure oil from the hydraulic pump to the plurality of hydraulic cylinders, a plurality of solenoid valves for generating a pilot pressure in response to a drive signal and outputting it to a pressure receiving portion on one side and a pressure receiving portion on the other side of the plurality of control valves, an operating device for generating and outputting an operation signal in response to an operation by an operator, and a control device for storing control characteristics consisting of the relationship between the operation signal and the drive signal for each of the plurality of solenoid valves and generating and outputting a drive signal corresponding to the operation signal from the operating device using the stored control characteristics. In the hydraulic excavator, when at least two of the plurality of hydraulic cylinders reach a stroke end in a predetermined driving direction, the control device simultaneously calibrates the control characteristics for the solenoid valves corresponding to the at least two hydraulic cylinders in the predetermined driving direction among the plurality of solenoid valves.

Advantages of the Invention

[0010] According to the hydraulic excavator of the present invention, it is possible to improve the calibration accuracy while shortening the calibration time.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0012] One embodiment of the present invention will be described with reference to the drawings.

[0013] FIG. 1 is a side view showing the structure of the hydraulic excavator in the present embodiment. Hereinafter, the front side (the left side in FIG. 1), the rear side (the right side in FIG. 1), the left side (the front side with respect to the paper surface of FIG. 1), and the right side (the back side with respect to the paper surface of FIG. 1) of the driver sitting on the driver's seat in the cab of the hydraulic excavator will be simply referred to as the front side, the rear side, the left side, and the right side.

[0014] The hydraulic excavator of the present embodiment includes a travelable traveling body 1, a revolving body 2 rotatably provided above the traveling body, and an articulated working device 3 connected to the revolving body 2. The traveling body 1 travels by a traveling motor (not shown). The revolving body 2 revolves by a revolving motor 4 (see FIG. 2 described later).

[0015] The working device 3 includes a boom 5 rotatably connected to the revolving body 2, an arm 6 rotatably connected to the boom 5, a bucket 7 (working tool) rotatably connected to the arm 6, a boom cylinder 8 for rotating the boom 5, an arm cylinder 9 for rotating the arm 6, a bucket cylinder 10 (working tool cylinder) for rotating the bucket 7, and angle sensors 11A, 11B, 11C for detecting the rotation angles of the boom 5, the arm 6, and the bucket 7 respectively (11A is shown in FIG. 3 described later). The boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 are a plurality of hydraulic cylinders for driving the working device 3.

[0016] The revolving body 2 includes a driver's cab 12 where the driver gets on, a machinery room 14 for housing equipment such as an engine 13 (prime mover), and a counterweight 15 for balancing with the working device 3. Inside the driver's cab 12 of the revolving body 2, a driver's seat (not shown) on which the driver sits is provided. In front of the driver's seat, a traveling operation device (not shown) for instructing the traveling of the traveling body 1 is arranged. On the left side of the driver's seat, a working operation device 16A (see FIG. 2 described later) for instructing the turning of the revolving body 2 and the rotation of the arm 6 is arranged. On the right side of the driver's seat, a working operation device 16B (see FIG. 2 described later) for instructing the rotation of the boom 5 and the rotation of the bucket 7 is arranged.

[0017] The above-described traveling motor, slewing motor 4, boom cylinder 8, arm cylinder 9, and bucket cylinder 10 are driven by a drive device mounted on the hydraulic excavator. FIG. 2 is a diagram showing a configuration related to the driving of the slewing motor 4, boom cylinder 8, arm cylinder 9, and bucket cylinder 10 among the configurations of the drive device of the hydraulic excavator in the present embodiment. FIG. 3 is a block diagram showing the functional configuration of the control device in the present embodiment.

[0018] The drive device of the present embodiment includes a variable displacement hydraulic pump 17 driven by an engine 13, a regulator 18 for varying the capacity of the hydraulic pump 17, a pilot pump (not shown) driven by the engine 13, a boom control valve 19 for controlling the flow of pressure oil from the hydraulic pump 17 to the boom cylinder 8, an arm control valve 20 for controlling the flow of pressure oil from the hydraulic pump 17 to the arm cylinder 9, a bucket control valve 21 (working tool control valve) for controlling the flow of pressure oil from the hydraulic pump 17 to the bucket cylinder 10, a slewing control valve 22 for controlling the flow of pressure oil from the hydraulic pump 17 to the slewing motor 4, the above-described operation devices 16A, 16B, a control device 23, and a plurality of solenoid valves 24A, 24B to 27A, 27B. Further, in order to calibrate the control characteristics for the solenoid valves 24A, 24B to 27A, 27B (details will be described later), a plurality of pressure sensors 28A, 28B to 31A, 31B for detecting the pilot pressures output from the solenoid valves 24A, 24B to 27A, 27B are provided.

[0019] The operating device 16A includes an operation lever that can be operated by the driver in the front-rear direction and the left-right direction, a first potentiometer that generates and outputs a first operation signal according to the operation amount on the front side of the operation lever, a second potentiometer that generates and outputs a second operation signal according to the operation amount on the rear side of the operation lever, a third potentiometer that generates and outputs a third operation signal according to the operation amount on the left side of the operation lever, and a fourth potentiometer that generates and outputs a fourth operation signal according to the operation amount on the right side of the operation lever.

[0020] The operating device 16B includes an operation lever that can be operated by the driver in the front-rear direction and the left-right direction, a fifth potentiometer that generates and outputs a fifth operation signal according to the operation amount on the front side of the operation lever, a sixth potentiometer that generates and outputs a sixth operation signal according to the operation amount on the rear side of the operation lever, a seventh potentiometer that generates and outputs a seventh operation signal according to the operation amount on the left side of the operation lever, and an eighth potentiometer that generates and outputs an eighth operation signal according to the operation amount on the right side of the operation lever.

[0021] The control device 23 includes a processor that executes processing according to a program, a memory that stores programs and data, and an interface that can communicate with an external terminal carried by a service technician or an internal terminal installed in the driver's cab 12. Functionally, the control device 23 includes a drive signal generation unit 32, a drive signal output unit 33, a capacitance signal generation unit 34, a capacitance signal output unit 35, and a calibration unit 36.

[0022] The drive signal generation unit 32 of the control device 23 stores a first control characteristic that is preset such that the first drive signal increases as the above-described first operation signal (in other words, the operation amount of the operation lever) increases, which is a relationship between the first operation signal and the first drive signal. When the first operation signal from the operating device 16A is input, the first drive signal corresponding to the first operation signal is generated using the first control characteristic and output to the solenoid unit of the electromagnetic valve 27B for right rotation via the drive signal output unit 33.

[0023] The solenoid valve 27B uses the discharge pressure from the pilot pump as the source pressure to generate a pilot pressure corresponding to the first drive signal and outputs it to the pressure receiving portion on the right side of the swing control valve 22 in the drawing. As a result, the swing control valve 22 is switched to the switching position on the right side in the drawing, and the pressurized oil from the hydraulic pump 17 is supplied to the upper port of the swing motor 4 via the swing control valve 22, causing the swing motor 4 to rotate in one direction. Consequently, the swing body 2 swings to the right.

[0024] The drive signal generation unit 32 of the control device 23 stores a second control characteristic consisting of the relationship between the second operation signal and the second drive signal, which is preset such that the second drive signal increases as the above-described second operation signal (in other words, the operation amount of the operation lever) increases. Then, when the second operation signal from the operation device 16A is input, a second drive signal corresponding to the second operation signal is generated using the second control characteristic and output to the solenoid portion of the solenoid valve 27A for left swing via the drive signal output unit 33.

[0025] The solenoid valve 27A uses the discharge pressure from the pilot pump as the source pressure to generate a pilot pressure corresponding to the second drive signal and outputs it to the pressure receiving portion on the left side of the swing control valve 22 in the drawing. As a result, the swing control valve 22 is switched to the switching position on the left side in the drawing, and the pressurized oil from the hydraulic pump 17 is supplied to the lower port of the swing motor 4 via the swing control valve 22, causing the swing motor 4 to rotate in the opposite direction. Consequently, the swing body 2 swings to the left.

[0026] The drive signal generation unit 32 of the control device 23 stores a third control characteristic consisting of the relationship between the third operation signal and the third drive signal, which is preset such that the third drive signal increases as the above-described third operation signal (in other words, the operation amount of the operation lever) increases. Then, when the third operation signal from the operation device 16A is input, a third drive signal corresponding to the third operation signal is generated using the third control characteristic and output to the solenoid portion of the solenoid valve 25B for arm damping via the drive signal output unit 33.

[0027] The solenoid valve 25B generates a pilot pressure corresponding to the third drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the right side of the arm control valve 20 in the drawing. As a result, the arm control valve 20 is switched to the switching position on the right side in the drawing, and the pressure oil from the hydraulic pump 17 is supplied to the upper port of the arm cylinder 9 via the arm control valve 20, causing the arm cylinder 9 to contract. As a result, the arm 6 dumps.

[0028] The drive signal generation unit 32 of the control device 23 stores a fourth control characteristic consisting of the relationship between the fourth operation signal and the fourth drive signal, which is preset so that the fourth drive signal increases as the above-described fourth operation signal (in other words, the operation amount of the operation lever) increases. Then, when the fourth operation signal from the operation device 16A is input, a fourth drive signal corresponding to the fourth operation signal is generated using the fourth control characteristic, and is output to the solenoid portion of the solenoid valve 25A for the arm cloud via the drive signal output unit 33.

[0029] The solenoid valve 25A generates a pilot pressure corresponding to the fourth drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the left side of the arm control valve 20 in the drawing. As a result, the arm control valve 20 is switched to the switching position on the left side in the drawing, and the pressure oil from the hydraulic pump 17 is supplied to the lower port of the arm cylinder 9 via the arm control valve 20, causing the arm cylinder 9 to extend. As a result, the arm 6 clouds.

[0030] The drive signal generation unit 32 of the control device 23 stores a fifth control characteristic consisting of the relationship between the fifth operation signal and the fifth drive signal, which is preset so that the fifth drive signal increases as the above-described fifth operation signal (in other words, the operation amount of the operation lever) increases. Then, when the fifth operation signal from the operation device 16B is input, a fifth drive signal corresponding to the fifth operation signal is generated using the fifth control characteristic, and is output to the solenoid portion of the solenoid valve 24B for lowering the boom via the drive signal output unit 33.

[0031] The solenoid valve 24B generates a pilot pressure corresponding to the fifth drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the right side in the drawing of the boom control valve 19. As a result, the boom control valve 19 is switched to the switching position on the right side in the drawing, and the pressurized oil from the hydraulic pump 17 is supplied to the upper port in the drawing of the boom cylinder 8 via the boom control valve 19, causing the boom cylinder 8 to contract. As a result, the boom 5 descends.

[0032] The drive signal generation unit 32 of the control device 23 stores the sixth control characteristic, which is the relationship between the sixth operation signal and the sixth drive signal, set in advance such that the sixth drive signal increases as the above-described sixth operation signal (in other words, the operation amount of the operation lever) increases. Then, when the sixth operation signal from the operation device 16B is input, the sixth drive signal corresponding to the sixth operation signal is generated using the sixth control characteristic, and is output to the solenoid portion of the boom raising solenoid valve 24A via the drive signal output unit 33.

[0033] The solenoid valve 24A generates a pilot pressure corresponding to the sixth drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the left side in the drawing of the boom control valve 19. As a result, the boom control valve 19 is switched to the switching position on the left side in the drawing, and the pressurized oil from the hydraulic pump 17 is supplied to the lower port in the drawing of the boom cylinder 8 via the boom control valve 19, causing the boom cylinder 8 to extend. As a result, the boom 5 ascends.

[0034] The drive signal generation unit 32 of the control device 23 stores the seventh control characteristic, which is the relationship between the seventh operation signal and the seventh drive signal, set in advance such that the seventh drive signal increases as the above-described seventh operation signal (in other words, the operation amount of the operation lever) increases. Then, when the seventh operation signal from the operation device 16B is input, the seventh drive signal corresponding to the seventh operation signal is generated using the seventh control characteristic, and is output to the solenoid portion of the bucket crowd solenoid valve 26A via the drive signal output unit 33.

[0035] The solenoid valve 26A generates a pilot pressure corresponding to the seventh drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the left side in the drawing of the bucket control valve 21. As a result, the bucket control valve 21 is switched to the switching position on the left side in the drawing, and the pressure oil from the hydraulic pump 17 is supplied to the port on the lower side in the drawing of the bucket cylinder 10 via the bucket control valve 21, causing the bucket cylinder 10 to extend. As a result, the bucket 7 crowds.

[0036] The drive signal generation unit 32 of the control device 23 stores an eighth control characteristic that is preset such that the eighth drive signal increases as the above-described eighth operation signal (in other words, the operation amount of the operation lever) increases, which is a relationship between the eighth operation signal and the eighth drive signal. Then, when the eighth operation signal from the operation device 16B is input, the eighth drive signal corresponding to the eighth operation signal is generated using the eighth control characteristic, and is output to the solenoid portion of the solenoid valve 26B for bucket dump via the drive signal output unit 33.

[0037] The solenoid valve 26B generates a pilot pressure corresponding to the eighth drive signal using the discharge pressure from the pilot pump as the source pressure, and outputs it to the pressure receiving portion on the right side in the drawing of the bucket control valve 21. As a result, the bucket control valve 21 is switched to the switching position on the right side in the drawing, and the pressure oil from the hydraulic pump 17 is supplied to the port on the upper side in the drawing of the bucket cylinder 10 via the bucket control valve 21, causing the bucket cylinder 10 to contract. As a result, the bucket 7 dumps.

[0038] The capacity signal generation unit 34 of the control device 23 stores a relationship between the maximum value of the operation signal and the capacity signal that is preset such that the capacity signal increases as the maximum value of the operation signal increases. Then, the maximum value of the operation signals input from the operation devices 16A and 16B is selected, the capacity signal is generated using the above-described relationship, and is output to the regulator 18 via the capacity signal output unit 35. The regulator 18 varies the capacity of the hydraulic pump 17 (specifically, the tilt angle of the swash plate) according to the capacity signal.

[0039] The calibration unit 36 of the control device 23 simultaneously calibrates the control characteristics of the boom raising solenoid valve 24A, the arm crowd solenoid valve 25A, and the bucket crowd solenoid valve 26A in response to the calibration command of pattern 1 from the terminal. Also, in response to the calibration command of pattern 2 from the terminal, the control characteristics of the arm dump solenoid valve 25B and the bucket dump solenoid valve 26B are simultaneously calibrated. Further, in response to the calibration command of pattern 3 from the terminal, the control characteristics of the boom lowering solenoid valve 24B are calibrated. Also, in response to the calibration command of pattern 4 from the terminal, the control characteristics of the left rotation solenoid valve 27A are calibrated. Further, in response to the calibration command of pattern 5 from the terminal, the control characteristics of the right rotation solenoid valve 27B are calibrated. The details of the calibration process for each pattern will be described.

[0040] First, the calibration process of pattern 1 will be described with reference to FIG. 4. FIG. 4 is a flowchart showing the calibration process of pattern 1 of the control device in the present embodiment.

[0041] The calibration unit 36 of the control device 23 determines in step S1 whether a calibration command of pattern 1 has been received from the terminal. When a calibration command of pattern 1 is received, the process proceeds to steps S2 to S4.

[0042] The calibration unit 36 of the control device 23 determines in step S2 whether the boom cylinder 8 has reached the stroke end on the boom raising side (in other words, the extending side) based on the detection result of the angle sensor 11A. In step S3, based on the detection result of the angle sensor 11B, it is determined whether the arm cylinder 9 has reached the stroke end on the arm crowd side (in other words, the extending side). In step S4, based on the detection result of the angle sensor 11C, it is determined whether the bucket cylinder 10 has reached the stroke end on the bucket crowd side (in other words, the extending side). Note that the order of steps S2 to S4 is not important.

[0043] If the boom cylinder 8 has not reached the stroke end on the boom raising side, the arm cylinder 9 has not reached the stroke end on the arm cloud side, or the bucket cylinder 10 has not reached the stroke end on the bucket cloud side, the process proceeds to step S5. The calibration unit 36 of the control device 23 transmits a display command to the terminal at step S5 to cause the terminal to display a message indicating that, for example, the preparation for calibration of pattern 1 is not complete.

[0044] On the other hand, if the boom cylinder 8 has reached the stroke end on the boom raising side, the arm cylinder 9 has reached the stroke end on the arm cloud side, and the bucket cylinder 10 has reached the stroke end on the bucket cloud side (see FIG. 5), the process proceeds to step S6. The calibration unit 36 of the control device 23 simultaneously calibrates the control characteristics for the boom raising solenoid valve 24A, the arm cloud solenoid valve 25A, and the bucket cloud solenoid valve 26A at step S6.

[0045] Specifically, the calibration unit 36 of the control device 23 outputs a capacity signal for setting the capacity of the hydraulic pump 17 to the minimum value to the capacity signal output unit 35. The capacity signal output unit 35 preferentially outputs the capacity signal from the calibration unit 36 to the regulator 18 over the capacity signal from the capacity signal generation unit 34. The regulator 18 adjusts the capacity of the hydraulic pump 17 to the minimum value, thereby adjusting the discharge flow rate of the hydraulic pump 17 to the minimum value (for example, the discharge flow rate of the hydraulic pump that is minimally required to drive the hydraulic actuator).

[0046] The calibration unit 36 of the control device 23 simultaneously outputs a predetermined sixth drive signal, a predetermined fourth drive signal, and a predetermined seventh drive signal (in other words, the sixth drive signal, the fourth drive signal, and the seventh drive signal from which a predetermined target pilot pressure should be obtained) to the drive signal output unit 33. The drive signal output unit 33 preferentially outputs the drive signal from the calibration unit 36 to the solenoid valves 24A, 25A, 26A over the drive signal from the drive signal generation unit 32.

[0047] The calibration unit 36 of the control device 23 calculates the difference between a predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 28A, and corrects the sixth control characteristic (specifically, the relationship between the sixth operation signal and the sixth drive signal) for the solenoid valve 24A using this difference. Further, the difference between a predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 29A is calculated, and the fourth control characteristic (specifically, the relationship between the fourth operation signal and the fourth drive signal) for the solenoid valve 25A is corrected using this difference. Also, the difference between a predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 30A is calculated, and the seventh control characteristic (specifically, the relationship between the seventh operation signal and the seventh drive signal) for the solenoid valve 26A is corrected using this difference. Thereafter, the process proceeds to step S7, and a display command is transmitted to the terminal to cause the terminal to display, for example, a message indicating that the calibration of pattern 1 has been completed.

[0048] Next, the calibration process for pattern 2 will be described with reference to FIG. 6. FIG. 6 is a flowchart showing the calibration process for pattern 2 of the control device in the present embodiment.

[0049] The calibration unit 36 of the control device 23 determines in step S8 whether a calibration command for pattern 2 has been received from the terminal. When a calibration command for pattern 2 is received, the process proceeds to steps S9 and S10.

[0050] The calibration unit 36 of the control device 23 determines in step S9 whether the arm cylinder 9 has reached the stroke end on the arm dump side (in other words, the shortening side) based on the detection result of the angle sensor 11B. In step S10, it is determined whether the bucket cylinder 10 has reached the stroke end on the bucket dump side (in other words, the shortening side) based on the detection result of the angle sensor 11C. Note that the order of steps S9 and S10 is not important.

[0051] If the arm cylinder 9 has not reached the stroke end on the arm dump side, or if the bucket cylinder 10 has not reached the stroke end on the bucket dump side, the process proceeds to step S11. The calibration unit 36 of the control device 23 transmits a display command to the terminal at step S11 to cause the terminal to display a message indicating that, for example, the preparation for calibration of pattern 2 is not complete.

[0052] On the other hand, if the arm cylinder 9 has reached the stroke end on the arm dump side and the bucket cylinder 10 has reached the stroke end on the bucket dump side (see Fig. 7), the process proceeds to step S12. The calibration unit 36 of the control device 23 simultaneously calibrates the control characteristics for the solenoid valve 25B for arm dump and the solenoid valve 26B for bucket dump at step S12.

[0053] Specifically, the calibration unit 36 of the control device 23 outputs a capacity signal for setting the capacity of the hydraulic pump 17 to the minimum value to the regulator 18 via the capacity signal output unit 35. The regulator 18 adjusts the capacity of the hydraulic pump 17 to the minimum value, thereby adjusting the discharge flow rate of the hydraulic pump 17 to the minimum value.

[0054] The calibration unit 36 of the control device 23 simultaneously outputs a predetermined third drive signal and a predetermined eighth drive signal (in other words, the third drive signal and the eighth drive signal that should obtain a predetermined target pilot pressure) to the solenoid valves 25B and 26B via the drive signal output unit 33. The calibration unit 36 of the control device 23 calculates the difference between the predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 29B, and uses this difference to correct the third control characteristic for the solenoid valve 25B (specifically, the relationship between the third operation signal and the third drive signal). Also, the difference between the predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 30B is calculated, and this difference is used to correct the eighth control characteristic for the solenoid valve 26B (specifically, the relationship between the eighth operation signal and the eighth drive signal). Then, the process proceeds to step S13, and a display command is transmitted to the terminal to cause the terminal to display a message indicating that, for example, the calibration of pattern 2 is complete.

[0055] Note that the calibration of Pattern 2 in this embodiment does not include the calibration of the solenoid valve 24B for boom lowering. The reason is that it is difficult to bring the boom cylinder 8 to the stroke end on the boom lowering side unless the hydraulic excavator is placed in a special location.

[0056] Next, the calibration processes for Patterns 3 to 5 will be described with reference to FIG. 8. FIG. 8 is a flowchart showing the calibration processes for Patterns 3, 4, or 5 in the control device of this embodiment.

[0057] The calibration unit 36 of the control device 23 determines in step S14 whether a calibration command for Pattern 3, 4, or 5 has been received from the terminal. When a calibration command for Pattern 3, 4, or 5 is received, the process proceeds to steps S15 and S16.

[0058] The calibration unit 36 of the control device 23 determines in step S15 whether the boom cylinder 8 has reached the stroke end on the boom raising side based on the detection result of the angle sensor 11A. In step S16, it determines whether the arm cylinder 9 has reached the stroke end on the arm crowd side based on the detection result of the angle sensor 11B. Note that the order of steps S15 and S16 does not matter.

[0059] If the boom cylinder 8 has not reached the stroke end on the boom raising side or the arm cylinder 9 has not reached the stroke end on the arm crowd side, the process proceeds to step S17. The calibration unit 36 of the control device 23 transmits a display command to the terminal in step S17 to cause the terminal to display a message indicating that, for example, the preparation for the calibration of Pattern 3, 4, or 5 is not complete.

[0060] On the other hand, when the boom cylinder 8 reaches the stroke end on the boom raising side and the arm cylinder 9 reaches the stroke end on the arm crowd side (see FIG. 5), the process proceeds to step S18. The calibration unit 36 of the control device 23 starts calibrating the control characteristics for the boom lowering solenoid valve 24B, the left rotation solenoid valve 27A, or the right rotation solenoid valve 27B in accordance with the calibration command of pattern 3, 4, or 5 at step S18.

[0061] Specifically, the calibration unit 36 of the control device 23 outputs a capacity signal for minimizing the capacity of the hydraulic pump 17 to the regulator 18 via the capacity signal output unit 35. The regulator 18 adjusts the discharge flow rate of the hydraulic pump 17 to the minimum value by adjusting the capacity of the hydraulic pump 17 to the minimum value.

[0062] The calibration unit 36 of the control device 23 outputs a predetermined fifth drive signal (in other words, the fifth drive signal for which a predetermined target pilot pressure should be obtained) to the solenoid valve 24B via the drive signal output unit 33. The calibration unit 36 of the control device 23 calculates the difference between the predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 28B, and corrects the fifth control characteristics for the solenoid valve 24B (specifically, the relationship between the fifth operation signal and the fifth drive signal) using this difference. Then, the process proceeds to step S19, and a display command is transmitted to the terminal to display a message indicating that the calibration of, for example, pattern 3 has been completed on the terminal.

[0063] Alternatively, the calibration unit 36 of the control device 23 outputs a predetermined second drive signal (in other words, the second drive signal for which a predetermined target pilot pressure should be obtained) to the solenoid valve 27A via the drive signal output unit 33. The calibration unit 36 of the control device 23 calculates the difference between the predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 31A, and corrects the second control characteristics for the solenoid valve 27A (specifically, the relationship between the second operation signal and the second drive signal) using this difference. Then, the process proceeds to step S19, and a display command is transmitted to the terminal to display a message indicating that the calibration of, for example, pattern 4 has been completed on the terminal.

[0064] Alternatively, the calibration unit 36 of the control device 23 outputs a predetermined first drive signal (in other words, the first drive signal that should obtain a predetermined target pilot pressure) to the solenoid valve 27B via the drive signal output unit 33. The calibration unit 36 of the control device 23 calculates the difference between the predetermined target pilot pressure and the pilot pressure detected by the pressure sensor 31B, and corrects the first control characteristic (specifically, the relationship between the first operation signal and the first drive signal) for the solenoid valve 27B using this difference. Then, it proceeds to step S19, transmits a display command to the terminal, and causes the terminal to display a message indicating that, for example, the calibration of pattern 5 has been completed.

[0065] As described above, in this embodiment, when the boom cylinder 8 reaches the stroke end on the boom raising side, the arm cylinder 9 reaches the stroke end on the arm crowd side, and the bucket cylinder 10 reaches the stroke end on the bucket crowd side, the control characteristics of the solenoid valve 24A for boom raising, the solenoid valve 25A for arm crowd, and the solenoid valve 26A for bucket crowd are calibrated simultaneously. Thereby, compared with the case of calibrating the solenoid valves one by one, the calibration time can be shortened. Also, different from the case of simultaneously inputting pilot pressure to the pressure receiving portions on one side and the other side of the control valve as in Patent Document 1, vibration of the control valve does not occur. Further, when the boom cylinder 8 reaches the stroke end on the boom raising side, the arm cylinder 9 reaches the stroke end on the arm crowd side, and the bucket cylinder 10 reaches the stroke end on the bucket crowd side, and the boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 do not operate, so their vibrations do not occur and are not transmitted to the control valve or the like. Furthermore, by setting the discharge flow rate of the hydraulic pump 17 to the minimum value, the vibration of the hydraulic pump 17 transmitted to the control valve or the like is suppressed. Therefore, the vibration of the pilot pressure detected by the pressure sensors 28A, 29A, and 30A can be suppressed, and the calibration accuracy can be improved.

[0066] Also, in the present embodiment, calibration of the control characteristics for the solenoid valve 25B for arm damping and the solenoid valve 26B for bucket damping is simultaneously performed in a state where the arm cylinder 9 has reached the stroke end on the arm damping side and the bucket cylinder 10 has reached the stroke end on the bucket damping side. Thereby, compared with the case of calibrating the solenoid valves one by one, the calibration time can be shortened. Also, unlike the case of simultaneously inputting pilot pressure to the pressure receiving portions on one side and the other side of the control valve as in Patent Document 1, vibration of the control valve does not occur. Further, since the arm cylinder 9 has reached the stroke end on the arm damping side and the bucket cylinder 10 has reached the stroke end on the bucket damping side, and the arm cylinder 9 and the bucket cylinder 10 do not operate, their vibrations do not occur and are not transmitted to the control valve or the like. Furthermore, by setting the discharge flow rate of the hydraulic pump 17 to the minimum value, vibration of the hydraulic pump 17 transmitted to the control valve or the like is suppressed. Therefore, vibration of the pilot pressure detected by the pressure sensors 29B and 30B can be suppressed, and the calibration accuracy can be improved.

[0067] Also, in the present embodiment, calibration of the control characteristics for the solenoid valve 24B for boom lowering, the solenoid valve 27A for left turning, or the solenoid valve 27B for right turning is started in a state where the boom cylinder 8 has reached the stroke end on the boom raising side and the arm cylinder 9 has reached the stroke end on the arm crowd side. Thereby, although the boom cylinder 8 or the swing motor 4 operates, the moment of the working device 3 is reduced to reduce the inertial force, so that vibration of the boom cylinder 8 or the swing motor 4 is suppressed. Furthermore, by setting the discharge flow rate of the hydraulic pump 17 to the minimum value, vibration of the boom cylinder 8 or the swing motor 4 is suppressed. Therefore, vibration of the pilot pressure detected by each pressure sensor can also be suppressed, and the calibration accuracy can be improved.

[0068] In the above-described embodiment, when the control device 23 receives the calibration command of Pattern 1, taking as an example the case where the control characteristics of the boom raising electromagnetic valve 24A, the arm cloud electromagnetic valve 25A, and the bucket cloud electromagnetic valve 26A are simultaneously calibrated in a state where the boom cylinder 8 has reached the stroke end on the boom raising side, the arm cylinder 9 has reached the stroke end on the arm cloud side, and the bucket cylinder 10 has reached the stroke end on the bucket cloud side, the description is not limited thereto. When the control device 23 receives the calibration command of Pattern 1, the control characteristics of the boom raising electromagnetic valve 24A, the arm dump electromagnetic valve 25B, and the bucket dump electromagnetic valve 26B may be simultaneously calibrated in a state where the boom cylinder 8 has reached the stroke end on the boom raising side, the arm cylinder 9 has reached the stroke end on the arm dump side, and the bucket cylinder 10 has reached the stroke end on the bucket dump side. In this case, when the control device 23 receives the calibration command of Pattern 2, the control characteristics of the arm cloud electromagnetic valve 25A and the bucket cloud electromagnetic valve 26A may be simultaneously calibrated in a state where the arm cylinder 9 has reached the stroke end on the arm cloud side and the bucket cylinder 10 has reached the stroke end on the bucket cloud side.

[0069] Alternatively, when the control device 23 receives the calibration command of Pattern 1, the control characteristics of the boom raising electromagnetic valve 24A, the arm cloud electromagnetic valve 25A, and the bucket dump electromagnetic valve 26B may be simultaneously calibrated in a state where the boom cylinder 8 has reached the stroke end on the boom raising side, the arm cylinder 9 has reached the stroke end on the arm cloud side, and the bucket cylinder 10 has reached the stroke end on the bucket dump side. In this case, when the control device 23 receives the calibration command of Pattern 2, the control characteristics of the arm dump electromagnetic valve 25B and the bucket cloud electromagnetic valve 26A may be simultaneously calibrated in a state where the arm cylinder 9 has reached the stroke end on the arm dump side and the bucket cylinder 10 has reached the stroke end on the bucket cloud side.

[0070] Alternatively, when the control device 23 receives the calibration command of Pattern 1, with the boom cylinder 8 reaching the stroke end on the boom raising side, the arm cylinder 9 reaching the stroke end on the arm dump side, and the bucket cylinder 10 reaching the stroke end on the bucket cloud side, the control characteristics of the electromagnetic valve 24A for boom raising, the electromagnetic valve 25B for arm dump, and the electromagnetic valve 26A for bucket cloud may be calibrated simultaneously. In this case, when the control device 23 receives the calibration command of Pattern 2, with the arm cylinder 9 reaching the stroke end on the arm cloud side and the bucket cylinder 10 reaching the stroke end on the bucket dump side, the control characteristics of the electromagnetic valve 25A for arm cloud and the electromagnetic valve 26B for bucket dump may be calibrated simultaneously.

[0071] Also, in the above-described embodiment, the case where the control device 23 controls the regulator 18 to adjust the discharge flow rate of the hydraulic pump 17 to the minimum value when receiving a calibration command of any one of Patterns 1 to 5 from the terminal has been described as an example, but it is not limited thereto. When the control device 23 receives a calibration command of any one of Patterns 3 to 5, from the perspective that the boom cylinder 8 or the swing motor 4 operates, the regulator 18 is controlled to adjust the discharge flow rate of the hydraulic pump 17 to the minimum value. However, when receiving a calibration command of Pattern 1 or 2, from the perspective that the hydraulic cylinder does not operate, it may not be necessary to adjust the discharge flow rate of the hydraulic pump 17 to the minimum value.

[0072] Also, in the above-described embodiment, when the control device 23 receives a calibration command from the terminal, the case where the regulator 18 is controlled to adjust the capacity of the hydraulic pump 17 to the minimum value to thereby adjust the flow rate of the hydraulic pump 17 to the minimum value has been described as an example. However, the present invention is not limited thereto. When the control device 23 receives a calibration command from the terminal, the engine 13 may be controlled to adjust the rotational speed of the engine 13 to the minimum value, thereby adjusting the flow rate of the hydraulic pump 17 to the minimum value. That is, the flow rate adjustment device that adjusts the discharge flow rate of the hydraulic pump 17 may be the engine 13 instead of or in addition to the regulator 18. Further, if the influence of the vibration of the hydraulic pump 17 is small, the control device 23 does not have to adjust the flow rate of the hydraulic pump 17 to the minimum value when receiving a calibration command from the terminal.

[0073] Also, in the above-described embodiment, the plurality of detectors that detect a plurality of state quantities that change respectively in accordance with the driving of the boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10 have been described as an example in the case of being the angle sensors 11A, 11B, and 11C that detect the rotation angles of the boom 5, the arm 6, and the bucket 7. However, the present invention is not limited thereto. The plurality of detectors may be a plurality of stroke sensors that detect the strokes of the boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10. That is, the control device 23 may determine the states of the boom cylinder 8, the arm cylinder 9, and the bucket cylinder 10, etc. based on the detection results of the plurality of stroke sensors.

Explanation of Reference Numerals

[0074] 1 Traveling body 2 Slewing body 3 Working device 4 Slewing motor 5 Boom 6 Arm 7 Bucket 8 Boom cylinder 9 Arm cylinder 10 Bucket cylinder 13 Engine 16A, 16B Operating device 17 Hydraulic pump 18 Regulator 19 Boom control valve 20 Arm control valve 21 Bucket control valve 22 Swing control valve 23 Control device 24A Solenoid valve for raising the boom 24B Solenoid valve for lowering the boom 25A Solenoid valve for arm crowding 25B Solenoid valve for arm dumping 26A Solenoid valve for bucket crowding 26B Solenoid valve for bucket dumping 27A Solenoid valve for left turning 27B Solenoid valve for right turning

Claims

1. A traveling body, a revolving body rotatably provided above the traveling body, a multi-joint working device connected to the revolving body, a plurality of hydraulic cylinders for driving the working device, a hydraulic pump, a plurality of control valves for respectively controlling the flow of pressure oil from the hydraulic pump to the plurality of hydraulic cylinders, a plurality of solenoid valves that generate pilot pressure according to a drive signal and output it to a pressure receiving part on one side and a pressure receiving part on the other side of the plurality of control valves, an operating device that generates and outputs an operation signal according to an operator's operation, and stores control characteristics consisting of the relationship between the operation signal and the drive signal for each of the plurality of solenoid valves, and uses this to generate and output the drive signal corresponding to the operation signal from the operating device. In a hydraulic excavator equipped with a control device, In a state where at least two of the plurality of hydraulic cylinders reach the stroke end in a predetermined driving direction among the plurality of hydraulic cylinders, the control device simultaneously calibrates the control characteristics for the solenoid valves corresponding to the at least two hydraulic cylinders in the predetermined driving direction among the plurality of solenoid valves. The hydraulic excavator is characterized by this.

2. In the hydraulic excavator according to Claim 1, The working device has a boom, an arm, and a bucket that are rotatably connected to each other. The plurality of hydraulic cylinders are composed of a boom cylinder that rotates the boom, an arm cylinder that rotates the arm, and a bucket cylinder that rotates the bucket. The plurality of control valves are composed of a boom control valve that controls the flow of pressure oil from the hydraulic pump to the boom cylinder, an arm control valve that controls the flow of pressure oil from the hydraulic pump to the arm cylinder, and a bucket control valve that controls the flow of pressure oil from the hydraulic pump to the bucket cylinder. The plurality of solenoid valves include a boom raising solenoid valve and a boom lowering solenoid valve that respectively output pilot pressure to a pressure receiving portion on one side and a pressure receiving portion on the other side of the boom control valve, an arm crowd solenoid valve and an arm dump solenoid valve that respectively output pilot pressure to a pressure receiving portion on one side and a pressure receiving portion on the other side of the arm control valve, and a bucket crowd solenoid valve and a bucket dump solenoid valve that respectively output pilot pressure to a pressure receiving portion on one side and a pressure receiving portion on the other side of the bucket control valve. The control device simultaneously calibrates the control characteristics for the boom raising solenoid valve, the arm crowd solenoid valve, and the bucket crowd solenoid valve in a state where the boom cylinder reaches the stroke end on the boom raising side, the arm cylinder reaches the stroke end on the arm crowd side, and the bucket cylinder reaches the stroke end on the bucket crowd side. The hydraulic excavator is characterized by this.

3. In the hydraulic excavator according to claim 2, The control device simultaneously calibrates the control characteristics for the arm dump solenoid valve and the bucket dump solenoid valve in a state where the arm cylinder reaches the stroke end on the arm dump side and the bucket cylinder reaches the stroke end on the bucket dump side. The hydraulic excavator is characterized by this.

4. In the hydraulic excavator according to claim 3, The control device starts calibrating the control characteristics for the boom lowering solenoid valve in a state where the boom cylinder reaches the stroke end on the boom raising side and the arm cylinder reaches the stroke end on the arm crowd side. The hydraulic excavator is characterized by this.

5. In the hydraulic excavator according to claim 1, A swing motor that swings the swing body, A swing control valve that controls the flow of pressure oil from the hydraulic pump to the swing motor, A left-turn electromagnetic valve and a right-turn electromagnetic valve that respectively output pilot pressure to the pressure-receiving part on one side and the pressure-receiving part on the other side of the swing control valve are provided. The working device has a boom, an arm, and a bucket that are rotatably connected to each other. The plurality of hydraulic cylinders are composed of a boom cylinder that rotates the boom, an arm cylinder that rotates the arm, and a bucket cylinder that rotates the bucket. The control device starts calibration of the control characteristics for the left-turn or right-turn electromagnetic valve in a state where the boom cylinder reaches the stroke end on the boom-raising side and the arm cylinder reaches the stroke end on the arm-crowd side. The hydraulic excavator is characterized by this.

6. In the hydraulic excavator according to any one of claims 1 to 3, A flow rate adjusting device for adjusting the discharge flow rate of the hydraulic pump is provided. The control device controls the flow rate adjusting device to adjust the discharge flow rate of the hydraulic pump to the minimum value in a state where at least two of the hydraulic cylinders reach the stroke end in the predetermined driving direction, and simultaneously calibrates the control characteristics for the electromagnetic valve corresponding to the predetermined driving direction of the at least two hydraulic cylinders. The hydraulic excavator is characterized by this.

7. In the hydraulic excavator according to claim 4 or 5, A flow rate adjusting device for adjusting the discharge flow rate of the hydraulic pump is provided. The control device controls the flow rate adjusting device to adjust the discharge flow rate of the hydraulic pump to the minimum value in a state where the boom cylinder reaches the stroke end on the boom-raising side and the arm cylinder reaches the stroke end on the arm-crowd side, and starts calibration of the control characteristics for the electromagnetic valve. The hydraulic excavator is characterized by this.

8. In the hydraulic excavator according to claim 1, A plurality of detectors for detecting a plurality of state quantities that respectively change according to the driving of the plurality of hydraulic cylinders are provided. The control device determines, based on the detection results of the plurality of detectors, whether or not the at least two hydraulic cylinders have reached the stroke end in the predetermined driving direction, and when the at least two hydraulic cylinders have not reached the stroke end in the predetermined driving direction, transmits a display command for causing a display indicating that calibration preparation is not complete, a hydraulic shovel characterized by the above.

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