JP2012072636A - Operation system of hydraulic shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation system of a hydraulic shovel capable of evading a working state in which a severe overload is applied to a multi-joint front, evading damage to the multi-joint front due to the overload and prolonging the service life.SOLUTION: As pilot valves of respective hydraulic operation type control valves 24-26 of a boom cylinder and an arm cylinder, proportional solenoid valves 28-33 are provided. The proportional solenoid valves 28-33 are operated by a controller 38 which receives electric signals from electric type operation levers 35-37 outputting the electric signals corresponding to an operation amount respectively. At least one of a boom and an arm is provided with distortion gauges 17, 18 for overload detection. Signal suppressing means is provided to suppress operation signals to the proportional solenoid valves 29, 30, 32 when load signals detected by the distortion gauges 17, 18 exceed a reference value in performing drilling operation.

Description

  The present invention relates to an operation system for a hydraulic excavator, and more particularly to an operation system for extending the life by avoiding an overload applied to an articulated front having a bucket for excavation.

  The hydraulic excavator is configured by installing an upper swing body on a lower traveling body and attaching an articulated front to a swing frame of the upper swing body. The articulated front is composed of a boom, an arm, an excavation bucket, and a hydraulic cylinder that raises and lowers them. This excavation work of the hydraulic excavator is performed by rotating the boom and arm downward and rotating the excavating bucket backward (upper revolving body side).

  When such a hydraulic excavator excavates a hard excavation object such as a crushed stone site, a mine, a coal topsoil, or limestone, for example, the load applied to the articulated front becomes large. When an overload is continuously applied to the multi-joint front in this way, damage may occur, such as cracking in the boom or arm. When such damage occurs, it becomes necessary to repair it or replace parts, and excavation work cannot be performed during this repair period. When a hydraulic excavator becomes a central working machine for crushed stone work as in a crushed stone site, if the excavator stops for repair or the like, the entire operation is stopped. For this reason, it is necessary to operate the hydraulic excavator in a state where failure due to accumulation of overload does not occur as much as possible.

  In this way, in order to prevent failure due to accumulation of overload and to extend the life of a work machine such as a hydraulic excavator, in Patent Document 1, a strain gauge is attached to a boom or an arm to detect the load, and the work machine There has been proposed a display device for a work machine that displays information on an operation or work method for promoting improvement related to the durability of the work machine when an operation or work method for reducing durability is performed. Specifically, when it is determined from the strain gauge detection data that the work state is severe, a warning such as “Let's reduce arm overload work” is issued by the display device. I am doing so.

JP 2005-163470 A

  However, as described in the above-mentioned Patent Document 1, it is sufficiently considered that an operator can ignore the warning or overlook the work only by detecting an overload or the like and issuing a warning. There is a problem that prevention of failure due to failure and life extension may not be achieved.

  In view of the above-described problems, the present invention provides a hydraulic excavator operating system that can avoid working conditions under severe overload with respect to the multi-joint front, and that can avoid damage to the multi-joint front due to overload and extend life. The purpose is to provide.

The operation system of the hydraulic excavator according to claim 1, wherein an upper swing body is installed on a lower traveling body, an articulated front is attached to a swing frame of the upper swing body,
The articulated front includes a boom attached to the revolving frame by a boom cylinder, an arm attached to the boom for rotation by an arm cylinder, and a bucket attached to the arm for rotation by a bucket cylinder. With
Proportional solenoid valve as a pilot valve of each hydraulically operated control valve of the boom cylinder, arm cylinder and bucket cylinder,
The controller for controlling the proportional solenoid valve is an operation system for a hydraulic excavator that generates an operation signal to the proportional solenoid valve in response to an electric signal from an electric operation lever provided corresponding to the proportional solenoid valve.
A strain gauge for overload detection attached to at least one of the boom and the arm;
An overload detection means provided in the controller for determining whether or not a load signal detected by the strain gauge exceeds a reference value when the operation lever is operated;
And a signal suppression unit that is provided in the controller and suppresses the operation signal to the proportional solenoid valve when an overload is detected by the overload detection unit.

The operation system of the hydraulic excavator according to claim 2 is the operation system of the hydraulic excavator according to claim 1,
A strain gauge for detecting overload attached to the boom is provided, and when an overload is detected by the strain gauge during excavation operation, proportional control for pilot of each control valve for the boom cylinder and the arm cylinder A signal suppression means for suppressing an operation signal to the electromagnetic valve is provided.

The operation system for a hydraulic excavator according to claim 3 is the operation system for a hydraulic excavator according to claim 1 or 2,
An overload detection strain gauge attached to the arm, and a pilot proportional solenoid valve for the control valve of the arm cylinder and the bucket cylinder when an overload is detected by the strain gauge during excavation operation It is characterized by comprising signal suppression means for suppressing the operation signal to

The operation system for a hydraulic excavator according to claim 4 is the operation system for a hydraulic excavator according to any one of claims 1 to 3.
The controller includes operation mode selection means for selecting whether or not to operate the signal suppression means based on the output of the strain gauge, and operation mode display means for displaying the operation mode selected by the operation mode selection means It is provided with.

  According to the first aspect of the present invention, when an overload is detected in a work site where an overload is likely to be applied to the articulated front, such as a crushed stone site, the operation signal from the controller to the proportional solenoid valve is suppressed. As a result, the flow rate of the hydraulic oil from the control valve to the hydraulic cylinder of the articulated front is suppressed, so that an overload is avoided on the articulated front. For this reason, damage to the multi-joint front due to accumulation of overload is avoided or slowed, and life extension can be achieved. In addition, damage to the multi-joint front due to accumulation of overload is avoided or slowed down, so that the total excavation work stoppage period due to the suspension of the excavator is shortened, and economy is achieved.

  According to the invention of claim 2, when a strain gauge is attached to the boom and an overload is detected by the strain gauge, an operation signal to the boom cylinder or the arm cylinder that causes the overload is suppressed. Here, since most of the overload generated in the boom depends on the operation of the boom cylinder or the arm cylinder, the boom overload can be efficiently avoided by limiting the flow rate of the hydraulic oil to the boom cylinder or the arm cylinder. .

  According to the invention of claim 3, a strain gauge is attached to the arm, and when an overload is detected by the strain gauge, an operation signal to the arm cylinder or the bucket cylinder is suppressed. Here, since most of the overload generated in the arm depends on the operation of the arm cylinder or the bucket cylinder, the arm overload can be efficiently avoided by limiting the flow rate of the hydraulic oil to the arm cylinder or the bucket cylinder. .

  According to the invention of claim 4, it is possible to select whether or not to perform an overload avoidance operation when an overload occurs. For this reason, for example, at sites where the frequency of overload is low, or at sites where excavation efficiency needs to be prioritized, it is possible not to suppress the operation signal at the time of overload. Work can be performed in a suitable operation mode. In addition, since the operation mode is displayed on the display means, the operator can work while understanding the current operation mode, and work while understanding the decrease in the operating speed of the hydraulic cylinder due to overload. Is possible.

1 is a side view showing an embodiment of a hydraulic excavator to which the present invention is applied. It is a bottom view which shows arrangement | positioning of the strain gauge provided in the articulated front of the hydraulic shovel of this embodiment. 1 is an electrohydraulic circuit diagram showing an embodiment of a hydraulic excavator operating system of the present invention. It is a functional block diagram of the controller of the operation system in this embodiment. (A) is a graph showing the relationship between the operating angle of the operating lever and the operating current during normal operation in this embodiment, and (B) is a graph showing the relationship between the operating angle of the operating lever and the operating current when overload is detected. It is. It is a graph which shows the relationship between the operating current in this embodiment, and the pilot pressure of a proportional solenoid valve. It is a graph which shows the relationship between the outlet side pilot pressure of the proportional solenoid valve in this embodiment, and the hydraulic fluid flow rate in a control valve.

  FIG. 1 is a side view showing an embodiment of a hydraulic excavator to which the present invention is applied. In FIG. 1, 1 is a crawler type lower traveling body, and 2 is an upper revolving body installed on the lower traveling body 1 via a revolving device 3. The upper swing body 2 is configured by mounting a hydraulic power unit 4, an operator cab 5, a counterweight 6 and the like on a swing frame 2a.

  Reference numeral 7 denotes an articulated front. The articulated front 7 is attached to the swing frame 2a by a boom cylinder 8 so as to be able to be lifted and lowered, and is attached to the tip of the boom 9 by an arm cylinder 10 so as to be rotatable. The arm 11 includes an excavation bucket 15 rotatably attached to the tip of the arm 11 via an arm link 13 and a bucket link 14 by a bucket cylinder 12.

  Reference numeral 17 denotes a strain gauge for detecting an overload applied to the boom 9 provided between a connecting portion with the boom cylinder 8 and a connecting portion with the arm 11 on the lower surface of the boom 9. Reference numeral 18 denotes a strain gauge for detecting overload on the arm 11 provided between the connecting portion of the boom 9 and the connecting portion of the arm link 13 on the lower surface of the arm 11. Each of these strain gauges 17 and 18 may be provided one by one, but in this embodiment, as shown in the bottom view of FIG. 2, even if the boom 9 and the arm 11 are slightly twisted, the boom Two strain gauges 17 and 18 are attached to both sides of the lower surface of the boom 9 and arm 11 so that the load applied to the arm 9 and the arm 11 can be detected.

  FIG. 3 is an electrohydraulic circuit diagram showing an operation system in the hydraulic excavator of this embodiment. In FIG. 3, 20 and 21 are main hydraulic pumps included in the hydraulic power unit 4, and 22 is also a pilot hydraulic pump. Reference numerals 24 and 26 are control valves for controlling switching and stopping of hydraulic oil discharged from the main hydraulic pump 20 to the boom cylinder 8 and bucket cylinder 12, respectively. These control valves 24 and 26 are cascade-connected, and a control valve for a traveling motor on one side of the lower traveling body 1 is further cascade-connected to these control valves 24 and 26, but the illustration is omitted. . Reference numeral 25 denotes a control valve that controls switching supply and stop of hydraulic oil discharged from the main hydraulic pump 21 to the arm cylinder 10. A control valve for the travel motor on the other side of the lower traveling body 1 and a control valve for the swing motor of the swivel device 3 are cascade-connected to the control valve 25, both of which are not shown.

  28 and 29 are proportional solenoid valves provided as pilot valves for switching the control valve 24. These proportional solenoid valves 28 and 29 switch the control valve 24 by controlling the supply of pilot pressure oil from the pilot hydraulic pump 22 to the operation chambers 24a and 24b of the boom cylinder 8 control valve 24, respectively.

  30 and 31 are proportional solenoid valves provided as pilot valves for switching the control valve 25 for the arm cylinder 10. These proportional solenoid valves 30 and 31 switch the control valve 25 by controlling the supply of pilot pressure oil from the pilot hydraulic pump 22 to the operation chambers 25a and 25b of the control valve 25 for the arm cylinder 10, respectively.

  32 and 33 are proportional solenoid valves provided as pilot valves for switching the control valve 26. These proportional solenoid valves 32 and 33 switch the control valve 26 by controlling the supply of pilot pressure oil from the pilot hydraulic pump 22 to the operation chambers 26a and 26b of the control valve 26 for the bucket cylinder 12, respectively.

  Reference numerals 35, 36, and 37 denote operation levers for the boom cylinder 8, the arm cylinder 10, and the bucket cylinder 12, respectively. 35a, 36a, and 37a denote operation signals (voltages) corresponding to the operation angles of the operation levers 35, 36, and 37, respectively. It is a device to generate. However, the operating levers 35 and 37 are actually the same operating lever, one operating lever 35 is operated in the front-rear direction and the other operating lever 37 is operated in the left-right direction.

  Reference numeral 38 denotes a controller. The controller 38 supplies an operation signal (current) corresponding to the operation angle of the operation levers 35 to 37 to the solenoids 28a to 33a of the proportional solenoid valves 28 to 33 via the signal lines 40 to 45, respectively. By doing so, the proportional solenoid valves 28 to 33 are switched. In the proportional solenoid valves 28 to 33, the opening degree of the internal flow path is controlled according to an operation signal supplied to the solenoids 28a to 33a via the signal lines 40 to 45, respectively. The pilot pressure applied to the operation chambers 24a, 24b to 26a, 26b of the control valves 24 to 26 corresponds to the operation signal as described later. As will be described later, the control valves 24 to 26 are controlled to the opening degree of the internal flow path according to the pilot pressure applied to the operation chambers 24b to 26a and 26b, and the flow rate of the hydraulic oil is controlled.

  A strain gauge 17 provided on the lower surface of the boom 9 and a strain gauge 18 provided on the lower surface of the arm 11 are connected to the controller 38. In this example, two strain gauges 17 and 17 are connected in parallel to each other and connected to the controller 38 (the same applies to the strain gauges 18 and 18), but they may be connected in series.

  47 is an operation mode selection means for selecting whether or not to perform control while suppressing the operation signal in consideration of signals from the strain gauges 17 and 18. The operation mode selection means 47 is configured by a switch, keyboard, touch panel, or the like provided in the cab 5. Reference numeral 48 denotes an operation mode display means for displaying whether or not the operation mode selected by the operation mode selection means 47 is to be controlled in consideration of the signals of the strain gauges 17 and 18. The operation mode display means 48 displays the operation mode with a lamp, sound or sound generator or display screen.

  FIG. 4 is a functional block diagram of the controller 38. The excavation work of the hydraulic excavator, that is, when the boom cylinder 8 that causes overload is contracted, when the arm cylinder 10 is extended, or when the bucket cylinder 12 is extended, 18 shows a configuration for suppressing an operation signal (current) from the controller 38 to the proportional solenoid valves 29, 30, 32 due to the overload detected by 18.

  In FIG. 4, overload detection means 50 and 51 detect overloads from the output signals of the strain gauges 17 and 18, respectively. Since these overload detection means 50 and 51 increase the resistance value of the strain gauges 17 and 18 as the load applied to the boom 9 and the arm 11 increases, for example, the strain gauges 17 and 18 are used as a Wheatstone bridge circuit. Incorporation, a change in the resistance value of the strain gauges 17 and 18 is detected as a change in voltage, the detected voltage is compared with a reference voltage serving as a threshold, and an overload occurs when the detected voltage exceeds the reference voltage. .

  The signal suppression means 52, 53, and 54 respectively receive operation signals from the devices 35a, 36a, and 37a that generate operation signals for the operation levers 35, 36, and 37, that is, signals corresponding to the operation angles of the operation levers 35, 36, and 37, respectively. When the overload is detected by the overload detection means 50 or 51, it is suppressed. However, when an operation mode in which signal suppression is not performed is selected by the operation mode selection means 47, signal suppression is not performed even in the case of an overload. The driver circuits 56, 57, and 58 generate currents that pass through the solenoids 29 a, 30 a, and 32 a of the proportional solenoid valves 29, 30, and 32, according to the operation signals of the operation levers 35, 36, and 37 that have passed through the signal suppression means 52, 53, and 54. This is a circuit to be generated.

  As shown in FIG. 4, the resistance value of the strain gauge 17 provided on the lower surface of the boom 9 is excessively detected by the overload detection unit 50 under the condition that the operation mode selected by the operation mode selection unit 47 is the operation signal suppression mode. In order to suppress the operation current I to the proportional solenoid valve 29 for contracting the boom cylinder 8 and the proportional solenoid valve 30 for extending the arm cylinder 10 when the value corresponds to the load, the signal suppression means 52 is used. , 53 to perform signal suppression.

  In addition, under the condition that the operation mode selected by the operation mode selection unit 47 is the operation signal suppression mode, the resistance value of the strain gauge 18 provided on the lower surface of the arm 11 is a value corresponding to an overload by the overload detection unit 51. In order to suppress the operation current to the proportional solenoid valve 30 for extending the arm cylinder 10 and the operation current I to the proportional solenoid valve 32 for extending the bucket cylinder 12, the signal suppression means 53, The signal suppression by 54 is performed.

  The operation of the boom cylinder 8 and the arm cylinder 10 may be performed simultaneously or separately. However, when the operation is performed simultaneously, both the operation modes of the boom cylinder 8 and the arm cylinder 10 are set. Both control in the signal suppression mode. In addition, the operation of the arm cylinder 10 and the bucket cylinder 12 may be performed simultaneously or independently, but when operating simultaneously, the operation modes of the arm cylinder 10 and the bucket cylinder 12 are both set. Both control in the signal suppression mode.

  If the overload state is canceled under the condition that the operation mode selected by the operation mode selection unit 47 is the operation signal suppression mode, signal suppression is not performed. However, in order to stabilize the operation, when an overload signal is detected, it is assumed that there is an overload state for a predetermined time, and the operation is performed in the signal suppression state, or the proportional solenoid valves 29, 30, When the operation signal to 32 becomes zero (or the pilot pressure in the operation chamber 24b of the control valve 24, the operation chamber 25a of the control valve 25, and the operation chamber 26a of the control valve 26 becomes the tank pressure), it is overloaded. It is preferable to perform the operation on the assumption.

  FIG. 5A shows the proportional solenoid valves 29, 30, from the operation angle θ of the operation levers 35, 36, 37 and the driver circuits 56, 57, 58 when the normal operation mode in which signal suppression due to overload is not performed is selected. It is a graph which shows the relationship with the operating current I supplied to 32 solenoids 29a, 30a, 32a. FIG. 5B shows the operation angle θ of the operation levers 35, 36, and 37 and the driver circuits 56, 57, and 58 when an overload is detected when the operation mode for suppressing the signal due to overload is selected. It is a graph which shows the relationship with the operation current I supplied to the solenoid of the proportional solenoid valves 29, 30, 32.

  As shown in FIG. 5A, when the normal operation mode in which signal suppression due to overload is not performed is selected, the driver circuit 56 is operated by operating the operation levers 35, 36, and 37 to the maximum operation angle (θmax). , 57 and 58, the operating current I supplied to the solenoids of the proportional solenoid valves 29, 30 and 32 can also be maximized (Imax). On the other hand, as shown in FIG. 5B, if an overload is detected when an operation mode for suppressing a signal due to an overload is selected, the operation angle θ of the operation levers 35, 36, and 37 is set to the maximum angle. As for (θmax), the operation current I is suppressed by the signal suppression means 52, 53, 54 and is supplied from the driver circuits 56, 57, 58 to the solenoids 29 a, 30 a, 32 a of the proportional solenoid valves 29, 30, 32. The operating current I is suppressed to a current Ia lower than the maximum current (Imax) by ΔI.

  FIG. 6 shows the operation current I supplied from the driver circuits 56, 57, 58 to the solenoids 29a, 30a, 32a of the proportional solenoid valves 29, 30, 32 and the secondary ports of the proportional solenoid valves 29, 30, 32. It is a graph which shows the relationship with the pilot pressure P added to the operation chambers 24b, 25a, 26a of the control valves 24, 25, 26. As shown in FIG. 6, when the operation current I is suppressed to Ia or less due to overload, the pilot pressure P is suppressed to a pilot pressure Pa or less that is lower than the maximum normal pilot pressure (Pmax) by a pressure indicated by ΔP. .

  7 shows the pilot pressure P generated in the secondary ports of the proportional solenoid valves 29, 30, 32 and applied to the operation chambers 24b, 25a, 26a of the control valves 24, 25, 26, and the control valves 24, 25, 26. 3 is a graph showing a relationship with hydraulic oil flow rate V. As shown in FIG. 7, when the operation current I is suppressed to Ia or less due to overload and the pilot pressure P is suppressed to Pa or less lower than the maximum pilot pressure (Pmax), the hydraulic oil in the control valves 24, 25, and 26 The flow rate is also suppressed to a flow rate Va which is smaller than the maximum flow rate (Vmax) by a flow rate indicated by ΔV.

  As described above, in this embodiment, when an overload is detected in the multi-joint front 7, the operation signals to the proportional electromagnetic valves 29, 30, 32 are suppressed, whereby the control valves 24, 25, Since the flow rate of the hydraulic oil from 26 to the boom cylinder 8, the arm cylinder 10, and the bucket cylinder 12 is suppressed, the overload is prevented from continuing. For this reason, damage to the articulated front 7 due to accumulation of overload can be avoided or delayed, and life extension can be achieved. Further, damage to the multi-joint front due to accumulation of overload is avoided or slowed down, so that the excavation work stoppage period due to the suspension of the hydraulic excavator is shortened, and economy is achieved.

  Specifically, for example, when a heavy load is applied, such as when excavating or quarrying with a hydraulic excavator after crushing the rock and reducing the amount of blasting to save money, at a crushed stone site, etc. Even overload work is avoided. In addition, when a hard object such as a mine, a coal topsoil, or limestone is excavated, the overload work is avoided and the life extension is achieved.

  In this embodiment, a strain gauge 17 is attached to the boom 9, and when an overload is detected by the strain gauge 17, an operation signal to the boom cylinder 8 or the arm cylinder 10 that causes the overload is generated. Although it is configured to be suppressed, the overload generated in the boom 9 is mainly due to the operation of the boom cylinder 8 or the arm cylinder 10, and therefore the boom is controlled by suppressing the flow rate of the hydraulic oil to the boom cylinder 8 or the arm cylinder 10. Can be avoided efficiently.

  In this embodiment, a strain gauge 18 is attached to the arm 11, and when an overload is detected by the strain gauge 18, an operation signal to the arm cylinder 10 or the bucket cylinder 12 causing the overload is generated. Although it is configured to be suppressed, the overload generated in the arm 14 is mainly due to the operation of the arm cylinder 10 or the bucket cylinder 12, and therefore, by suppressing the flow rate of the hydraulic oil to the arm cylinder 10 or the bucket cylinder 12, the arm 11 overloads can be avoided efficiently.

  In this embodiment, the operation mode selection means 47 is provided so that it is possible to select whether or not to perform an overload avoidance operation when an overload occurs. Therefore, priority is given to work efficiency depending on the situation of the work site. In this case, the operation can be performed in an operation mode in which overload avoidance is not performed. For this reason, for example, at sites where the frequency of overload is low, or at sites where excavation efficiency needs to be prioritized, it is possible not to suppress the operation signal at the time of overload. Work can be performed in a suitable operation mode. Further, since the operation mode is displayed on the display means 48, the operator can work while understanding the current operation mode, and work while understanding the decrease in the operating speed of the hydraulic cylinder due to overload. It becomes possible.

  The present invention provides a hydraulically operated pilot between the proportional solenoid valves 28 to 33 and the operation chambers 24a, 24b to 26a and 26b of the control valves 24 to 26 in the operation circuit of the boom cylinder 8, the arm cylinder 10 and the bucket cylinder 12. This can also be applied when a valve is provided. Moreover, when implementing this invention, in the range which does not deviate from the summary of this invention, not only the said embodiment but a various change and addition are possible.

1: Lower traveling body, 2: Upper revolving body, 2a: Revolving frame, 3: Revolving device, 4: Hydraulic power unit, 5: Driver's cab, 6: Counterweight, 7: Articulated front, 8: Boom cylinder, 9: Boom, 10: Arm cylinder, 11: Arm, 12: Bucket cylinder, 13: Arm link, 14: Bucket link, 15: Bucket, 17, 18: Strain gauge, 20, 21: Main hydraulic pump, 22: Pilot hydraulic pump 24: boom cylinder control valve, 25: arm cylinder control valve, 26: bucket cylinder control valve, 28-33: proportional solenoid valve, 35-37: operation lever, 38: controller, 47: operation mode selection means 48: Operation mode display means

Claims (4)

Install the upper swing body on the lower traveling body, attach the articulated front to the swing frame of the upper swing body,
The articulated front includes a boom attached to the revolving frame by a boom cylinder, an arm attached to the boom for rotation by an arm cylinder, and a bucket attached to the arm for rotation by a bucket cylinder. With
Proportional solenoid valve as a pilot valve of each hydraulically operated control valve of the boom cylinder, arm cylinder and bucket cylinder,
The controller for controlling the proportional solenoid valve is an operation system for a hydraulic excavator that generates an operation signal to the proportional solenoid valve in response to an electric signal from an electric operation lever provided corresponding to the proportional solenoid valve.
A strain gauge for overload detection attached to at least one of the boom and the arm;
An overload detection means provided in the controller for determining whether or not a load signal detected by the strain gauge exceeds a reference value when the operation lever is operated;
An operation system for a hydraulic excavator, comprising: a signal suppression unit that is provided in the controller and suppresses the operation signal to the proportional solenoid valve when an overload is detected by the overload detection unit. The operation system of the hydraulic excavator according to claim 1,
A strain gauge for detecting overload attached to the boom is provided, and when an overload is detected by the strain gauge during excavation operation, proportional control for pilot of each control valve for the boom cylinder and the arm cylinder An operation system for a hydraulic excavator, comprising signal suppression means for suppressing an operation signal to a solenoid valve. The operation system of the hydraulic excavator according to claim 1 or 2,
An overload detection strain gauge attached to the arm, and a pilot proportional solenoid valve for the control valve of the arm cylinder and the bucket cylinder when an overload is detected by the strain gauge during excavation operation A hydraulic excavator operation system comprising signal suppression means for suppressing an operation signal to the motor. The operation system of the hydraulic excavator according to any one of claims 1 to 3,
The controller includes operation mode selection means for selecting whether or not to operate the signal suppression means based on the output of the strain gauge, and operation mode display means for displaying the operation mode selected by the operation mode selection means A hydraulic excavator operation system characterized by comprising:

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