JP2002038533A - Hydraulic excavating vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic excavating vehicle which carries out desired work by controlling composite operation activated by a plurality of actuators without requiring a mastery degree of the operator, in response to selection of an operation mode by the operator under his hand. SOLUTION: The hydraulic excavating vehicle is comprised of an operating machine and pressure compensating valves 10 and 10a. The operating machine is driven by activation of at least two portions by means of the respective hydraulic actuators (hydraulic cylinders 2 and 3). The pressure compensating valves 10 and 10a are arranged across pressure oil feeding circuits 4 and 5 at respective locations between control valves 6 and 7 connected to operating levers 12 and 13, and the actuators (hydraulic cylinders 2 and 3). According to the hydraulic excavating vehicle thus constructed, when the operator selects the operation mode by using an operation mode selecting means (monitor 18) arranged in an operator's cab, the pressure compensating valves 10 and 10a are activated in response to signals from a controller 14 having a variable pressure compensating value function storage means, whereby pressure oil feeding amounts to the actuators are controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic excavation vehicle capable of rationally controlling the operation of a working machine in a construction machine having an excavating machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art Among various operations conventionally performed using a hydraulic excavator, for example, an operation of flattening the ground using a bucket 101 as a working machine (generally called a wiping operation) is shown in FIG. As shown in the example, the raising operation of the boom 102 and the excavation operation by the arm 103 are simultaneously performed by combining the operations of the operation cylinders 104 and 105. In this case, since the arm 103 moves in the direction of its own weight drop, the bucket trajectory from the work start point a cuts below the target ground line as shown by the dotted line b in the figure. In order to prevent such biting, the skill of the operator largely depends on the skill of the operator.

When a weight attachment is used for a working machine, for example, as shown in FIG. 7A (the same parts and devices as those described above are denoted by the same reference numerals), In the work performed using the crusher 106,
The weight of the crusher 106 attached to the tip of the arm 103 is heavier than that of a general bucket or the like, and there are many operations for operating the crusher 106 toward a higher place. When performing deep excavation work, as shown in FIG. 7 (b), in order to secure the ascending speed of the work implement, the boom 102 is moved upward with respect to the boom 102 and the arm 103 in order to secure the lifting speed. It is necessary to loosen the throttle (not shown) to increase the operation speed of the operation cylinder 104 on the boom 102 side. In any of the above cases, when performing the simultaneous composite operation of the raising operation of the boom 102 and the operation of the arm 103, the target operation cannot be performed smoothly unless the operation control of the operation cylinders 104 and 105 of both is performed in a proper manner. Even at the time of such work, the current situation is that it is solved by the skill of the operator, in other words, it depends on the skill of the operator.

As a prior art related to the present invention, a pressure compensating valve which is suitable for use in hydraulic control for simultaneously operating a plurality of actuators is disclosed in Japanese Patent Application Laid-Open No. H11-316611 filed by the present applicant. No., proposed by US Pat. It is disclosed that since the pressure compensating valve of this pressure compensating valve changes in accordance with the magnitude of the control pressure, a desired pressure compensating characteristic can be obtained by changing the control pressure.

[0005]

However, as described above, effective operation by combining a plurality of actuators has not been solved yet, and still involves the combined operation of an operator. There is a problem that the operator cannot perform the work efficiently unless the operator has a high level of skill in performing such kind of work.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and allows an operator to select a work mode at hand, thereby controlling a combined operation of a plurality of actuators without requiring a skill level. It is an object of the present invention to provide a hydraulic excavation vehicle having a function capable of performing the above operation.

[0007]

Means for Solving the Problems and Actions / Effects In order to achieve the above-mentioned object, a hydraulic excavator according to a first aspect of the present invention includes a working machine that operates by operating at least two parts by hydraulic actuators. In a hydraulic excavation vehicle in which a directional control valve and a pressure compensating valve are respectively provided in a pressure oil supply path to each of the actuators, according to a work mode selected by a work mode selecting means provided in a cab. The pressure compensation valve is actuated by a control signal from a controller having a variable pressure compensation value function storage means to control the amount of pressurized oil supplied to the actuator.

In the present invention, a supply ratio value to a plurality of actuators is preset in a controller as a variable pressure compensation value function storage means, and an operator selects a work mode by a work mode selection means provided in an operator's cab. By changing the throttled state of the pressure compensating valve in the pressure oil supply path to multiple actuators, the degree of pressure compensation can be controlled to match the work, and when the operation lever is operated, the pressure The control valve is operated to control while maintaining the degree of compensation of the supply amount of the working pressure oil supplied to the actuator. Therefore, according to the present invention, if a work mode is selected by the work mode selecting means, for example, two operating parts are set to different operating states under the selected condition, and one of the parts is quickly operated. ,
The other part is controlled so as to be slow, and it becomes possible to operate a plurality of actuators in a set procedure without depending on the skill of the operator.

In the present invention, it is preferable that the controller has a strong compensation function storage means as the variable pressure compensation value function storage means. Preferably, the variable pressure compensation value function storage means includes a weak compensation function storage means. In this case, for example, control is performed using the former strong compensation function storage means for arm operation, and conversely, fixed pressure compensation such as using weak compensation function storage means for boom operation is performed. There is an advantage that in a work involving a combined operation with a working machine having an arm and a boom, the work conditions of both can be defined and the operation can be rationally performed.

In the present invention, the work mode selection means is provided with a variable level adjustment switch together with the work mode selection switch, so that the degree of pressure compensation of the pressure compensation valve by the variable pressure compensation value function storage means can be varied. The configuration should be good. This has the advantage that the operating state settings of the plurality of actuators can be adjusted according to the working conditions other than the initial settings.

The hydraulic excavation vehicle according to the second aspect of the present invention further includes a working machine which operates at least two parts by operating respective hydraulic actuators, and includes a directional control valve in a pressure oil supply path to each of the actuators. In a hydraulic excavation vehicle provided with a pressure compensating valve, a monitor provided in a cab is provided with a work mode selecting means, and an electric signal from the work mode selecting means is transmitted through an electric resistor and an electromagnetic valve. The pressure compensating valve is operated by inputting to the pressure compensating valve to control the amount of pressurized oil supplied to the actuator.

According to the present invention, when the operation mode is selected by the monitor provided with the operation mode selection means provided in the operator's cab, the electric resistor (resistor) is operated by the selected electric signal, and the operation is started. Activate the connected solenoid valve, convert it to a hydraulic signal and control the degree of pressure compensation by the pressure compensating valve to a state suitable for the work, for example, to perform pressure compensation different from the setting condition by one pressure compensating valve By changing the operation state of the actuator on the selected side with respect to the other actuator, a plurality of actuators that are combined and operated by the operator according to their skills can be operated as set, thereby improving the work efficiency.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of a hydraulic excavator according to the present invention will be described with reference to the drawings.

This embodiment relates to a hydraulic excavator, and FIG.
FIG. 2 shows a hydraulic control circuit diagram showing a first embodiment of the present invention.

In this embodiment, a hydraulic pump 2 driven by an engine mounted on a vehicle body, a hydraulic cylinder 2 for operating a boom (corresponding to an actuator of the present invention) and a hydraulic cylinder 3 for operating an arm (corresponding to an actuator of the present invention). ), Pressure control valves 6, 7 are provided in the working pressure oil supply circuits 4, 5 for each bottom side, and a pressure compensating valve 10 is provided between the pressure control valve 6 (7) and the hydraulic cylinder 2 (3). , 10a are provided.

The left and right operation levers 11 and 12 are connected to the pressure control valves 6 and 7, respectively.
It is electrically connected to the controller 14 via 3, 13a. The operating load pressure is taken out from the outlet side oil passages 4 ', 5' of the pressure compensating valves 10, 10a in the working hydraulic oil supply circuits 4, 5 to the hydraulic cylinders 2, 3, and the pilot circuits 15, 15a are taken out. Is connected to the shuttle valve 16.

The pressure compensating valves 10 and 10a are connected to operating solenoid valves 17 and 17a for receiving pilot pressure oil from the pilot hydraulic pump 8, respectively. Solenoid valve 1
Electric signal circuits 30, 31 are connected by 7, 17a such that the pressure compensating valves 10, 10a are individually operated.

A well-known control means is incorporated in the controller 14, and as a variable pressure compensation value function storage means, the operation of the hydraulic cylinder 2 for operating the boom and the hydraulic cylinder 3 for operating the arm when performing complex work is performed. A command value for setting the pressure oil supply ratio is input in advance, and a value for setting a variable condition of the operating pressure oil supply ratio is input.
As the working pressure oil supply ratio, the working pressure oil supply ratio to both hydraulic cylinders 2 and 3 in a normal operation is 1: 1. On the other hand, for example, in the case of a clearance work, the supply ratio to the hydraulic cylinder 2 for boom operation and the hydraulic cylinder 3 for arm operation is as follows: boom operation 1: arm operation 0.8 In the case of a work to be used or a deep excavation work, it is set as 0.9 for boom operation: 1 for arm operation. Note that these values are not limited.

In contrast to such a controller 14, a monitor 18 having, for example, two selection operation switches (operation buttons) 18a and 18b according to the work mode is installed as a work mode selection means in a cab (not shown). I have. The monitor 18 is connected to the controller 14 by a signal circuit, and allows the operator to select the operating conditions of the boom and the arm according to the work mode by using the selection operation switches 18a and 18b when the operator performs a complex operation in the cab. It has been like that. The monitor 18 is provided with a variable level adjustment switch 19 (having a structure like a volume switch).
The operation can be performed by further finely changing the fixed control amount by 8b.

In this embodiment, for example, when performing a wiping operation, the operator selects the operation mode switch 18 of the operation mode of the monitor 18 installed in the cab.
When the (one) operation button of the target operation is pressed at a or 18b, a command signal is sent from the selected operation switch to the controller 14, and in this case, a command value suitable for the clearance operation is transmitted from the controller 14 to the operation electromagnetic controller. The signal is transmitted to the valve 17 (17a). That is, the hydraulic cylinder 2 for the boom operation
The operation solenoid valve 17 of the pressure compensating valve 10 in the working pressure oil supply circuit 4 and the operation solenoid valve 17a of the pressure compensation valve 10a in the working pressure oil supply circuit 5 to the hydraulic cylinder 3 for operating the arm. A predetermined signal is sent, and the operation solenoid valves 17, 1
The pressure compensating valves 10 and 10a are operated at a predetermined ratio so that the oil supply to the hydraulic cylinder 2 for boom operation is restricted by the operation 7a. Specifically, the pressure compensation valve 10a on the arm excavation side
The degree of squeezing.

As a result, the operating speed of the arm is lower than the operating speed of the boom. In other words, when the work for leveling the ground surface is performed by the bucket attached to the tip of the arm during the wiping operation, the bucket is moved forward. To perform the pulling operation to the side, the operation is performed in a state where the speed of raising the boom is slightly superior to the speed of pulling the arm (see FIG. 6). Therefore, when leveling, conventionally, the bucket was dug from the ground surface to finish it flat, and the movement of the arm and the boom was controlled with the skill associated with the experience of the operator, but a special skill is required. Without setting the leveling angle by the bucket, the leveling can be correctly performed only by operating the movement of the boom and the arm by the operation lever.

When performing an operation in which a large load acts on the arm side (deep excavation operation or operation using a weight attachment, see FIGS. 7A and 7B), the monitor 18 When another operation button is pressed, a command value suitable for the weight attachment operation is selected in the controller 14 by a signal from the operation switch. Then, a command signal corresponding thereto is transmitted to each operation solenoid valve 1.
The pressure compensating valves 10 and 10a are sent to the hydraulic cylinders 7 and 17a to operate the hydraulic compensating valves 10, 10a. Is also squeezed at a predetermined ratio. Specifically, the degree of restriction of the boom raising side pressure compensating valve 10a is relaxed. If the operator operates the operating levers 11 and 12 after setting the operating conditions of the arm and the boom according to the work in this manner, the operating speed of the arm operating hydraulic cylinder 3 will be higher than the operating speed of the boom operating hydraulic cylinder 2. For example, in the case of deep excavation work, raising the excavated soil by the bucket makes it possible to perform the operation of raising the boom while maintaining the state where the arm is pulled toward the front side, so that the bucket can remove the soil. You can fry efficiently.

Further, even when a heavy attachment is attached to the tip of the arm such as a dismantling crusher to perform dismantling work, it is possible to prevent the arm speed from decreasing with respect to the boom raising speed. Furthermore, when raising the boom while grasping an object with a crusher, the pump pressure has risen in order to grasp and hold the object with the crusher relief conventionally.
As a result, the pump discharge pressure decreases, and the boom raising speed decreases because the boom raising pressure compensating valve adjusts the flow rate. Therefore, in the case of the present invention, by lowering the area ratio of the boom raising pressure compensation, the pump pressure can be reduced, and the boom raising speed can be improved by giving priority to the flow rate ratio to the boom raising.

In the case where it is necessary to adjust the operation ratio of the boom or the arm depending on the working condition when actively operating the arm, the monitor 1 is used.
If the level is adjusted by operating the variable level adjustment switch 19 attached to the controller 8, the control command value is corrected from the initial set value by the controller 14 according to the set value, and the operation to both hydraulic cylinders is performed. The supply ratio of the pressure oil is changed, and a desired operation can be performed. Further, in setting the supply ratio of the working pressure oil to both hydraulic cylinders, if the supply condition to one of the hydraulic cylinders is fixed, only the supply condition to the other hydraulic cylinder is controlled. By doing so, the purpose can be achieved.

When the operation by the combined operation of the boom and the arm is completed, the selection of the operation mode by the selection operation button on the monitor 18 is released, and the pressure compensating valves 10 and 10a from the controller 14 are released.
Is released, and the operation returns to the normal operation. Therefore, after that, the pressure adjustment by the shuttle valve 16 is performed by detecting the load pressure of the hydraulic cylinders in the hydraulic pressure supply circuits 4 and 5 to both the hydraulic cylinders 2 and 3.

Next, the operation of the hydraulic excavating vehicle of this embodiment will be described with reference to the flowchart shown in FIG.

S1: When a special operation is performed depending on whether the operation is a normal operation or a special operation, the push button of the operation mode selection switch is pressed on the monitor 18 provided in the cab. When performing a special operation (for example, a clearance operation), the process proceeds to step S2. If No, the process moves to step S8 as normal work.

S2: It is determined whether or not the combined operation of the boom and arm is performed as a special operation. If it is a composite operation, the process proceeds to step S3. If No, the process moves to step S6 as a single operation.

S3: When the composite operation is selected, a predetermined pressure compensation level according to the operation is selected. In short, in the case of the clearance work, the controller 14 selects a pressure compensation level corresponding to the clearance work. S4: A command signal corresponding to the pressure compensation level selected from the controller 14 is transmitted to the arm-side operation solenoid valve 17a to operate the operation solenoid valve 17a.

S5: Operation levers 11 and 12 for compound operation
The pressure compensating valves 10 and 10a are operated by the operation solenoid valves 17 and 17a in accordance with the operation signal amount of the hydraulic pressure, and the supply of the working pressure oil to the hydraulic cylinders 2 and 3 is controlled by the pressure compensation, and the working machine is operated in combination. The desired work is performed. When the composite operation ends and returns to normal, step 1 is performed again.
Return to (S1).

On the other hand, if it is selected in step S2 that the operation of the boom and the arm is a single operation,
It operates as follows. S6: A hydraulic signal corresponding to the amount of operation signal from the operation levers 11, 12 is output (from the pressure control valves 6, 7). S7: The work implement is operated in accordance with the operation signal amount by the operation levers 11 and 12 in the single operation.

When the normal operation is selected in step S1, as in the case of the general operation, S8: A hydraulic signal corresponding to the operation signal amount of each of the operation levers 11 and 12 is generated (the pressure control valves 6 and 7). Output). S9: The work implement is operated according to the lever operation signal amount of the combined operation by the operation levers 11 and 12. When the operation of the working machine by the single operation or the normal operation is completed, the process returns to step S1 to shift to the next operation, and shifts to the next operation in the operation procedure.

As described above, in this embodiment, if the work mode corresponding to the target work is selected by the work mode selecting means (operation switch for selecting the work mode on the monitor) provided in the driver's cab, the controller is thereafter used. The ratio (compensation degree) of the supply amount of hydraulic pressure oil to the hydraulic cylinders (for boom operation and arm operation) of the working machine operating in advance is controlled by the pressure compensating valve, and then the operating lever is operated. By doing so, you can accomplish the task you want. Therefore, even if the operator's proficiency is low, the intended purpose can be achieved by operating the work machine smoothly without difficulty.

Next, as a second embodiment, the throttle of the pressure compensating valves 10, 10a is operated by the solenoid operated valves 17, 17a through the controller 14 in the first embodiment. Instead of the above, as shown in FIG. 3, a signal to the solenoid operated valves 17, 17a for operating the pressure compensating valves 10, 10a is electrically operated. In the second embodiment, since the basic configuration is the same as that of the above embodiment, the same or similar parts are denoted by the same reference numerals as those of the above embodiment.

In this embodiment, a command signal to the solenoid operated valves 17 and 17a is given from resistors 21 and 22 through resistors 21 and 22 from operation switches 18a and 18b for selecting a work mode provided on the monitor 18. Operating valve 17, 17
The throttle of the pressure compensating valves 10 and 10a is given by a hydraulic signal by a. The resistors 21 and 22
May be fixed or variable.

In the second embodiment constructed as described above, as a control means at the time of combined operation of the working machine, it operates in the same manner as in the first embodiment, and operates the boom in accordance with the selected work mode. The operation of the hydraulic cylinders 2 and 3 for operating the arm and the arm is controlled, so that the work can be easily performed without depending on a high level of skill.

FIG. 4 is a hydraulic circuit diagram showing an embodiment of the third embodiment. This embodiment has a configuration in which an electric operation lever is used. Since the basic configuration is the same as that of the above-described embodiment, the same or similar parts are denoted by the same reference numerals as in the above-described embodiment, and detailed description is omitted.

In the case where the electric operation lever is used, a potentiometer (not shown) is provided for transmitting the operation of the electric operation levers 25 and 26.
The voltage generated by the lever operation is converted into an electric signal by a potentiometer (normally, the upper limit is 5 V,
A neutral band is provided in a small range before and after, so as not to respond to the initial stage of the lever operation from the neutral position) to the controller 14, and a control signal corresponding to the
Each of the hydraulic cylinders 2, 3 is provided via an electromagnetic proportional valve 27, 27a.
The hydraulic pressure signal is transmitted to the operation units of the pressure control valves 6 and 7 provided in the operating pressure oil supply circuits 4 and 5 to the operating pressure oil supply circuits 4 and 5. In the same manner as in the first embodiment, an electromagnetically operated valve is provided for a pressure compensating valve 10, 10a provided between an outlet side of each of the pressure control valves 6, 7 and an input side of each of the hydraulic cylinders 2, 3. A hydraulic signal is input from each of the solenoid operated valves 17 and 17a.
Signal circuits 30 and 3 so that command signals are transmitted from
1 is connected.

In this embodiment, similarly to the above embodiment, the work mode is selected by the work mode selection operation switches 18a and 18b (operation buttons) on the monitor 18 provided in the operator's cab when the complex operation is required. When selected,
The selected operation signal is input to the controller 14.
An operation command signal corresponding to the selected operation mode is transmitted to the electromagnetic operation valves 17 and 17a by the controller 14,
The corresponding pressure compensating valves 10, 10a are throttled or loosened to control the amount of hydraulic pressure supplied to the corresponding operating hydraulic cylinders 2, 3. Therefore,
The supply amount of the operating pressure oil to one operating hydraulic cylinder is reduced or loosened to the other operating hydraulic cylinder so that the supply ratio of the operating pressure oil to the two hydraulic cylinders 2 and 3 is made different. You. As a result, there is a difference between the operating speeds of the arm and the boom, and the desired purpose can be easily achieved by performing a movement corresponding to the selected operation.

Next, the operation of the hydraulic excavator according to the third embodiment will be described with reference to the flowchart shown in FIG.

T1: When performing a special operation depending on whether the operation is a normal operation or a special operation, an operation mode selection switch 18a, 1 on a monitor 18 provided in an operator's cab.
8b Press any push button. When performing a special operation (for example, a clearance operation), the process proceeds to step S2. No
If so, the process moves to step T8 as a normal operation.

T2: It is determined whether or not the combined operation of the boom and arm is performed as a special operation. If it is a composite operation, the process proceeds to step T3. If No, the process moves to step T6 as a single operation.

T3: When the composite operation is selected, a predetermined pressure compensation level according to the operation is selected. In short, in the case of the clearance work, the controller 14 selects a pressure compensation level corresponding to the clearance work. T4: A command signal corresponding to the selected pressure compensation level is transmitted from the controller 14 to the arm-side electromagnetically operated valve 17a (the boom-side electromagnetically operated valve 17), and the electromagnetically operated valve 17
a (electromagnetic operation valve 17) is operated.

T5: solenoid operated valve 17a (electromagnetic operated valve 1)
The pressure compensating valve 10a (pressure compensating valve 10) is operated by the hydraulic signal according to 7), and the supply of working pressure oil to the hydraulic cylinder 3 (hydraulic cylinder 2) is controlled by the pressure compensation. Work is performed. The controller 14 outputs to the electromagnetic proportional valves 27 and 27a in accordance with the operation signal amounts of the operating levers 25 and 26 that perform the combined operation. The electromagnetic proportional valves 27 and 27a allow the pressure control valves 6 and 7 to adjust the level of the pressure compensation. The operation of the hydraulic cylinders 2 and 3 is controlled while maintaining this. When the composite operation ends and returns to normal, the process returns to step 1 (T1) again.

On the other hand, if it is selected in step T2 that the operation of the boom and the arm is a single operation,
It operates as follows. T6: An electric signal corresponding to the operation signal amount by the operation levers 25 and 26 is output to the controller 14. T7: The operation signal amount by the operation levers 25 and 26 of the single operation is output from the controller 14 to the electromagnetic proportional valves 27 and 27a, and the working machine is operated according to the operation signals by the hydraulic signals from the electromagnetic proportional valves 27 and 27a. You.

In step T1, when the normal operation is selected, the controller 14 outputs an electric signal corresponding to the operation signal amount of each of the operation levers 25 and 26 as in the general operation. T9: The work implement is operated according to the lever operation signal amount of the combined operation by the operation levers 25 and 26. After the operation of the work machine by the single operation or the normal operation is completed, the process returns to step 1 to proceed to the next operation, and the operation proceeds to the next operation in the above-described operation procedure. When the operation of the working machine in the single operation or the normal operation is completed, the process returns to step 1 to move to the next operation, and the operation moves to the next operation in the operation procedure.

As described above, also in the third embodiment, if the operation mode corresponding to the target operation is selected by the operation mode selection means (operation switches 18a and 18b for selecting the operation mode on the monitor 18) provided in the cab. Then, the ratio (compensation degree) of the supply amount of the working pressure oil to the working hydraulic cylinder (for operating the boom and for operating the arm) of the working machine, which is set in advance by the controller 14, is controlled by the pressure compensating valves 10 and 10a. Then, by operating the electric control lever, the intended work can be accomplished. Therefore, even if the operator's proficiency is low, the intended purpose can be achieved by operating the work machine smoothly without difficulty.

In the above description, the hydraulic cylinder is raised as the actuator to be controlled. However, the present invention can be applied to other types of hydraulic operating devices.

[Brief description of the drawings]

FIG. 1 is a hydraulic control circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation state of the hydraulic excavation vehicle according to the present embodiment.

FIG. 3 is a hydraulic control circuit diagram showing only a main part of the second embodiment.

FIG. 4 is a hydraulic control circuit diagram showing an embodiment of a third embodiment.

FIG. 5 is a flowchart showing an operation state of the hydraulic excavator of the third embodiment.

FIG. 6 is an explanatory diagram of a problem in a clearance work by a hydraulic shovel.

FIGS. 7A and 7B are diagrams illustrating a conventional work mode using a hydraulic excavator, wherein FIG. 7A illustrates a work machine having a heavy attachment, and FIG. It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Hydraulic cylinder for boom operation 3 Hydraulic cylinder for arm operation 4,5 Hydraulic oil supply circuit 6,7 Pressure control valve 8 Pilot hydraulic pump 10,10a Pressure compensation valve 11,12 Operating lever 14 Controller 15,15a Pilot circuit 16 Shuttle valve 17, 17a Operation solenoid valve 18 Monitor 18a, 18b Operation mode selection operation switch 19 Variable level adjustment switch 21, 22 Resistor 25, 26 Electric operation lever 27, 27a Electromagnetic proportional valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Koichi Kawamura 3-1-1 Ueno, Hirakata-shi, Osaka Prefecture Inside the Komatsu Manufacturing Osaka Plant (72) Inventor Toshio Yokoyama 3-1-1 Ueno, Hirakata-shi, Osaka 1 F-term in Osaka Plant of Komatsu Ltd. (reference) 2D003 AA01 AB03 BA02 BA06 BB03 CA02 DA03 DA04 DB02 3H089 AA27 AA74 BB15 CC06 CC12 DA03 DA08 DA13 DB23 DB25 DB29 EE03 EE14 EE22 EE34 EE36 GG02 JJ02

Claims (5)

[Claims] 1. A hydraulic system comprising: a working machine having at least two parts operated and operated by hydraulic actuators, respectively, and a directional control valve and a pressure compensating valve are respectively provided in a pressure oil supply path to each of the actuators. In the excavation vehicle, the pressure compensating valve is actuated by a control signal from a controller having a variable pressure compensation value function storage means according to a work mode selected by a work mode selection means provided in a driver's cab. A hydraulic excavation vehicle configured to control a supply amount of pressurized oil. 2. The hydraulic excavation vehicle according to claim 1, wherein said controller comprises a strong compensation function storage means as said variable pressure compensation value function storage means. 3. The hydraulic excavation vehicle according to claim 1, wherein the controller includes a weak compensation function storage unit as the variable pressure compensation value function storage unit in the controller. 4. The work mode selection means is provided with a variable level adjustment switch together with a work mode selection switch, so that the degree of pressure compensation of the pressure compensating valve by the variable pressure compensation value function storage means can be varied. Item 2. A hydraulic excavator according to item 1. 5. A hydraulic system comprising: a working machine operated by operating at least two parts by hydraulic actuators, and a directional control valve and a pressure compensating valve are respectively provided in a pressure oil supply path to each of the actuators. In the excavating vehicle, a monitor provided in a driver's cab is provided with a work mode selecting means, and an electric signal from the work mode selecting means is inputted to the pressure compensating valve via an electric resistor and an electromagnetic valve to be operated. A hydraulic excavation vehicle, wherein the hydraulic oil supply amount to the actuator is controlled.