JP2735580B2 - Hydraulic drive for civil and construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention divides the pressure oil of a main hydraulic pump through a plurality of diverting compensation valves to each of actuators provided corresponding to the diverting compensation valves. The present invention relates to a hydraulic drive device for a civil engineering / construction machine which can supply and actuate these actuators to perform a desired combined operation.

<Prior Art> FIG. 6 is a circuit diagram showing a hydraulic drive device of a hydraulic shovel as an example of this type of conventional hydraulic drive device for civil engineering and construction machinery.

The hydraulic drive device shown in FIG. 6 is driven by a prime mover 1, a variable displacement hydraulic pump driven by the prime mover 1, that is, a main hydraulic pump 2, and a hydraulic oil discharged from the main hydraulic pump 2. A swing motor 3 for rotating a swing body (not shown), and an actuator including a boom cylinder 4 for rotating a boom (not shown).

Further, a flow control valve for controlling the flow of pressure oil supplied from the main hydraulic pump 2 to the swing motor 3, that is, a swing direction control valve 5, and a branch flow compensation for controlling a pressure difference between the front and rear of the swing direction control valve 5 A valve 6, a flow control valve for controlling the flow of the pressure oil supplied from the main hydraulic pump 2 to the boom cylinder 4, that is, a boom directional control valve 7, and a differential pressure between the front and rear of the boom directional control valve 7. And a shunt compensation valve 8.

One of the driving portion 6a of the diverter compensation valve 6 are communicated to the tank, also in the one of the driving section 6a, summed control force of the force by the force and the load pressure of the spring 6c Fa ₁ is the shunt compensation valve given by open, the other drive section 6b, the control force Fa ₂ by the maximum load pressure of the circuit which is led through the pressure and the shuttle valve 9, 10 on the downstream side of the shunt compensation valve 6, the The flow compensating valve 6 is provided so as to close. Similarly, one drive unit 8a of the shunt compensating valve 8 is connected to the tank, and the other drive unit 8a receives a control force Fb _{1 that} is the sum of the force of the spring 8c and the load pressure. The shunt compensation valve 8 is provided so as to be opened, and the other drive unit 8b is provided with the shunt compensation valve 8.
Control force Fb ₂ by the pressure downstream of the pump and the maximum load pressure of the circuit
Is provided such that the shunt compensation valve 8 is closed.

The displacement of the main hydraulic pump 2 is controlled by a control actuator 12 driven by a flow regulating valve 11 which is switched according to the differential pressure between the discharge pressure of the main hydraulic pump 2 and the maximum load pressure of the circuit. Is done.

When the actuator is driven alone, for example, when the swing direction control valve 5 is switched to drive the swing motor 3 to operate a swing body (not shown), the pressure oil discharged from the main hydraulic pump 2 is supplied to the branching compensation valve 6. Is supplied to the turning motor 3 via the turning direction control valve 5. When a change occurs in the load pressure of the turning motor 3, the load pressure is guided to one drive unit 6 a of the shunt compensation valve 6. Thereby, the throttle amount of the branch flow compensating valve 6 is appropriately adjusted, and accordingly, the differential pressure across the turning direction control valve 5 is controlled to be kept constant. That is, the branch flow compensating valve 6 has a function of pressure compensation. This is the same in the diversion compensating valve 8 and the like related to the boom cylinder 4.

In addition, when the actuators are combinedly driven, for example, when the swing motor 3 and the boom cylinder 4 are combinedly driven with different driving pressures, these are operated by operating the swing direction control valve 5 and the boom direction control valve 7. When the required flow rate of the turning direction control valve 5 and the boom direction control valve 7, that is, the total flowable flow rate exceeds the maximum capacity of the main hydraulic pump 2, the self-pressure of each actuator and the maximum load pressure of the circuit are set. As a result, the throttle amounts of the flow compensating valves 6 and 8 are adjusted, and the flow rate guided to the turning direction control valve 5 and the flow rate guided to the boom direction control valve 7 are maintained at a constant flow rate ratio. Is controlled so as not to exceed the maximum capacity of the main hydraulic pump 2, the front-rear differential pressure between the turning directional control valve 5 and the boom directional control valve 7 is kept equal, and discharged from the main hydraulic pump 2. Pressure The shunt to be supplied to the swing motor 3 and the boom cylinder 4, it is possible to achieve combined operation such as turning the boom raising.

<Problems to be Solved by the Invention> Meanwhile, in the above-mentioned conventional hydraulic drive system for civil engineering and construction machinery, one drive unit 6a, 8a of each of the flow compensation valves 6, 8 is connected to a tank. Therefore, the diversion compensating valves 6 and 8 respond to changes in the tank pressure when the return oil from the swing motor 3 or the boom cylinder 4 flows into the tank.
, The driving state changes, and it is difficult to obtain stable control accuracy.

In addition, the shunt compensation valves 6 and 8 are driven via the forces of the springs 6c and 8c, and the manufacturing accuracy tends to vary between the springs 6c and 8c. Driving errors are likely to occur, and therefore, a variation in the manufacturing accuracy of the springs 6c and 8c may lead to a situation where a desired split ratio cannot be obtained, and the combined operability may be reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances in the related art, and has as its object to obtain stable driving of a shunt compensating valve regardless of a change in tank pressure, and to reduce a driving error between shunt compensating valves. An object of the present invention is to provide a hydraulic drive device for civil engineering and construction machinery that does not occur.

<Means for Solving the Problems> In order to achieve this object, an invention according to claim (1) of the present invention is driven by a main hydraulic pump and pressure oil supplied from the main hydraulic pump. A plurality of actuators, a flow control valve for controlling the flow of pressure oil supplied to these actuators, a diverting compensation valve for controlling a pressure difference between the front and rear of these flow control valves, and a flow discharged from the main hydraulic pump And a flow control means for controlling the pressure of the main hydraulic pump, and supplies the hydraulic oil of the main hydraulic pump to each of the actuators through the flow dividing compensation valve and the flow control valve, respectively. In the hydraulic drive of the machine, the same pilot relief pressure is applied to one drive of each of the shunt valves so that the shunt valves operate in the opening direction. And a control force adding means for applying a control force to the other drive unit of each of the shunt compensation valves so as to operate the shunt compensation valves in a closing direction. Means are pilot pumps,
The pilot pressure supply means includes a relief valve that regulates the magnitude of the pilot pressure discharged from the pilot pump, and a pipeline that connects the pilot pump and one of the drive units of the branch flow compensation valve. The control force applying means is provided on the side of the pipeline that connects the pilot pump and the other drive units of the respective flow dividing valves.

The invention according to claim (4) of the present invention relates to a main hydraulic pump, a plurality of actuators driven by hydraulic oil supplied from the main hydraulic pump, and a hydraulic oil supplied to these actuators. A flow control valve for controlling the flow;
A flow compensating valve for controlling the pressure difference before and after the flow control valve, and a flow control means for controlling a flow rate discharged from the main hydraulic pump. In the hydraulic drive device of the civil engineering and construction machine, which supplies the actuators to the respective actuators via the valves, and the actuators can be combinedly driven, one of the drive units of the shunt compensation valve has a shunt compensation function. Pilot pressure supply means for supplying the same pilot relief pressure so that the valves operate in the opening direction is provided, and the other drive units of the respective flow division compensating valves are operated so that these diversion compensating valves operate in the closing direction. A control force applying means for applying a control force, wherein the control force applying means controls the pressure of the hydraulic oil discharged from the main hydraulic pump and the actuator A differential pressure detecting device for detecting a differential pressure from the maximum load pressure, a controller connected to the differential pressure detecting device and having a storage unit for storing a functional relationship between the differential pressure and the control force in advance, and a controller output from the controller. Control pressure generating means for generating a control pressure applied to the other drive unit of the shunt compensating valve provided corresponding to the actuator in response to the control force signal.

<Operation> As described above, the same pilot relief pressure is supplied to one drive unit of each of the plurality of branch flow compensating valves by the pilot pressure supply means as described above (the invention according to claims 1 and 4). With such a configuration, these shunt compensating valves can be driven without being affected by the tank pressure at all, and therefore, stable driving of the shunt compensating valves can be obtained irrespective of changes in the tank pressure. In addition, the shunt compensating valve can be driven without the interposition of a spring force, and since a plurality of shunt compensating valves are driven by the same pilot relief pressure, a driving error between the shunt compensating valves hardly occurs.

<Example> Hereinafter, a hydraulic drive device of a civil engineering / construction machine according to the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram showing a first embodiment of a hydraulic drive device for a civil engineering / construction machine according to the present invention. This first embodiment is applied to a hydraulic shovel, and includes a prime mover 21 and this prime mover.
A constant displacement hydraulic pump driven by the main hydraulic pump 22a, a plurality of actuators driven by the hydraulic oil discharged from the main hydraulic pump 22a, that is, a turning motor 23, and a left traveling motor 24; A right traveling motor 25, a boom cylinder 26, an arm cylinder 27, and a bucket cylinder 28 are provided. The swing motor 23 drives a swing body (not shown), the left running motor 24 and the right running motor 25 drive crawler tracks (not shown), and the boom cylinder 26, the arm cylinder 27, and the bucket cylinder 28 Drive the arm and bucket.

Also, the swing motor 23, the left traveling motor 24, the right traveling motor
25, a boom cylinder 26, an arm cylinder 27, a flow control valve for controlling the flow of the pressure oil supplied to each of the bucket cylinder 28, that is, a turning direction control valve 29, a left running direction control valve 30, and a right running direction. Direction control valve 31, boom direction control valve 32, arm direction control valve 33, bucket direction control valve 34
And diversion compensating valves 35, 36, 37, 38, 39, 40 provided corresponding to these flow control valves.

Also, the displacement of the main hydraulic pump 22a described above is:
The flow rate is controlled by flow control means, that is, a flow control valve 42a, which is driven in accordance with a pressure difference ΔP _LS between a pump pressure guided through the pipe 43a and a maximum load pressure guided through the pipe 44a.

Further, a pilot pressure supply means for supplying the same pilot relief pressure to one of the driving units 35a to 40a of each of the above-mentioned diversion compensating valves 35 to 40 so that these diversion compensating valves 35 to 40 operate in the opening direction. The pilot pressure supply means includes, for example, a pilot pump 61a, a relief valve 61b for defining the magnitude of the pilot pressure discharged from the pilot pump 61a, and a pilot pump 6
1a and one drive unit 35a-4 of each of the branch flow compensating valves 35-40
0a and a pipeline 61c communicating therewith.

Further, the other drive unit of each of the shunt compensation valves 35 to 40
35b to 40b are provided with a control force adding means 52 for giving a control force so that these branch flow compensating valves 35 to 40 operate in the closing direction.The control force adding means 52 is, for example, a main hydraulic pump.
A differential pressure detecting device 53 for detecting a differential pressure ΔP _LS between the pressure of the pressure oil discharged from the nozzle 22a and the maximum load pressure of the actuator, and a function of the differential pressure and the control force which is connected to the differential pressure detecting device 53 in advance. A storage unit 57 for storing the relationship, an input unit 55, and a calculation unit
56, a controller 59 having an output unit 58, and a control pressure applied to the other driving units 35b to 40b of the flow dividing compensation valves 35 to 40 provided corresponding to the actuators in accordance with the control force signal output from the controller 59. And a control pressure generating means 60a for generating pressure.

The above-described control pressure generating means 60a is provided with a shunt compensation valve 35-40.
Six solenoid valves 62a, 62 provided corresponding to each of
b, 62c, 62d, 62e, 62f and the above-described pilot pump 61a for supplying a pilot pressure to these solenoid valves 62a to 62f.
And the above-described relief valve 61b that regulates the magnitude of the pilot pressure output from the pilot pump 61a. The solenoid valve 62a and the drive unit 35b of the shunt compensating valve 35 are connected via a pipe 51a, and likewise the solenoid valve
Each of 62b-62f and the drive units 36b-4 of the branch flow compensating valves 36-40
0b is communicated with each of the pipes 51b to 51f. In addition, the solenoid valves 62a to 62f output drive signals a, b, c, d, e, and
The solenoid valve 62a is driven in accordance with each of the pressures f, and the drive section of the solenoid valve 62a receives the return back pressure of the relief valve 61b as a common back pressure. Of the components of the control pressure generating means 60a, the portion including the relief valve 61b and the solenoid valves 62a to 62f is formed in one block structure as shown by a two-dot chain line. The lengths of 51a to 51f are set to substantially the same length. In addition, along with the above-described block, the length of the pipe 61c connected to one of the driving units 35a to 40a of each of the flow dividing compensating valves 35 to 40 is also set to substantially the same length.

And, the storage unit 57 of the controller 59, for example, the functional relationship between the differential pressure [Delta] P _LS as shown in FIG. 2 corresponds to the control force F to shunt compensation valve 35 according to the swing motor 23, i.e. the differential pressure [Delta] P _LS A characteristic line in which the control force F decreases in proportion to the increase of the left traveling motor 24, although not shown, is stored.
Right running motor 25, boom cylinder 26, arm cylinder 2
7, the characteristic lines having slopes different from the characteristic lines shown in FIG. 2 corresponding to the flow dividing compensating valves 36 to 40 relating to the bucket cylinder 28, that is, the functional relationship between the differential pressure ΔP _LS and the control force F are individually It is remembered. The inclination of each characteristic line described above is set in consideration of a combination of actuator speeds suitable for performing various operations.

Further, in this embodiment, work detecting means for detecting which actuator is to be driven, for example, provided in correspondence with each of the directional control valves 29 to 34, and detects the drive of these directional control valves 29 to 34. Drive detectors 80a, 80b, 80c, 80d, 80e, 8
0f is provided.

In the first embodiment configured as described above, when the actuator is driven alone, for example, when the turning direction control valve 29 is switched to drive the turning motor 23, the drive detector 80a turns Operating direction control valve 29 is detected, and controller 59 responds to the signal.
2 is read out by the storage unit 57 of FIG. 2, and the operation unit 56 and the functional relationship of FIG.
The control force F is determined from the differential pressure ΔP _LS detected by 53 and input to the calculation unit 56 via the input unit 55, and a control signal a corresponding to the control force F is output to the drive unit of the solenoid valve 62a. Is done. As a result, the solenoid valve 62a operates by an amount corresponding to the braking force F, and the control pressure obtained by appropriately adjusting the pilot pressure by the pilot pump 61a is guided to the other drive unit 35b of the branch flow compensating valve 35 via the conduit 51a. The shunt compensation valve 35 is to be operated in the closing direction. However, the pilot pressure by the pilot pump 61a is set
The control flow is guided to one drive unit 35a of the shunt compensating valve 35 to oppose the above-described control pressure, and attempts to operate the shunt compensating valve 35 in an opening direction. Therefore, the shunt compensation valve 35
Changes in the load pressure of the swing motor 23 and the main hydraulic pump 22a
The throttle amount is adjusted in accordance with the change in the differential pressure ΔP _LS which is the difference between the discharge pressure of the directional control valve 29 and the load pressure. The flow rate according to the operation amount of the direction control valve 29 is supplied to the swing motor 23, and the desired swing motor 23 can be driven independently, that is, the swing body (not shown) can be swung.

In addition, during combined driving of the actuator, for example, during combined driving of the swing motor 23 and the boom cylinder 26, signals from the drive detectors 80a and 80d receive signals from the input unit 55 of the controller 59.
And the control force corresponding to the shunt compensation valve 35 according to the differential pressure ΔP _LS detected by the differential pressure detecting device 53 based on these signals, and the control force corresponding to the shunt compensation valve 36. The control force is individually obtained by the calculation unit 56 of the controller 59,
The control force signal a is output from the output unit 58 of the controller 59 to the solenoid valve 62.
a, the control force signal d is output to the solenoid valve 62d, and these solenoid valves 62a, 62d are driven. Along with this, a pilot pressure, which is a constant pressure by the pilot pump 61a, is guided to one of the driving portions 35a, 38a of the branch flow compensating valves 35, 38,
A control pressure corresponding to the control force F corresponding to the functional relationship in FIG. 2 is guided to the other drive unit 35b of the shunt compensation valve 35 via the solenoid valve 62a, and is applied to the other drive unit 38b of the shunt compensation valve 38. Is the solenoid valve 6
A control pressure corresponding to a control force F corresponding to a characteristic line (not shown) having a slope different from the functional relationship in FIG. 2 is led through 2d, whereby the throttle amounts of the branching compensation valves 35 and 38 are appropriately adjusted. That is, the throttle amount of the branch flow compensating valve on the side where the load pressure is small is adjusted so as to be larger than the throttle amount of the branch flow compensating valve on the side where the load pressure is large, and the flow amount flowing through the turning direction control valve 35 and the boom The flow rate to the directional control valve 38 is a predetermined flow rate ratio, and the sum of these flow rates is
Control is performed so as not to exceed the displacement of a, and the combined drive of the swing motor 23 and the boom cylinder 26 can be performed, so that the desired combined swing and boom operation can be performed.

The combined driving of the actuators is not limited to the combination of the swing motor 23 and the boom cylinder 26 described above, and the same operation as described above is performed regardless of the combination of the actuators.

In the first embodiment configured as described above, the shunt compensating valve 35
The same pilot relief pressure is supplied to one of the drive units 35a to 40a via the pipe 61c, so that the influence of the change in tank pressure due to the return oil from the actuator is compensated. This does not affect the driving of the valves 35 to 40, so that the shunt compensation valves 35 to 40 can be driven stably irrespective of changes in the tank pressure, and excellent control accuracy can be obtained.

Further, the shunt compensation valves 35 to 40 can be driven without interposing a spring force in one of the driving portions 35a to 40a of the shunt compensation valves 35 to 40, and the shunt compensation valves 35 to 40 are driven by the same pilot relief pressure. Since 40 is driven, the shunt compensation valve 35-40
A desired split ratio can be obtained with almost no drive error between each other, and excellent combined operability can be obtained.

In addition, the relief valve 61b and the solenoid valves 62a to 62f are blocked as one structure, and each of the branching compensation valves 35 to
Each pipeline connected to one of the drive units 35a to 40a of 40
Since the length of 61c is set to substantially the same length, there is no drive error between the respective shunt compensating valves 35 to 40 due to the pressure loss of the line 61c, which also provides an excellent composite. Operability is obtained.

Further, as described above, the relief valve 61b and the solenoid valves 62a-62
f is blocked as one structure, and the solenoid valve 6
Since the same back pressure of the relief valve 61b is applied to the drive units 2a to 62f, and the lengths of the conduits 51a to 51f are set to be substantially equal, the distance between the solenoid valves 62a to 62f is reduced. No drive errors occur and therefore these solenoid valves
There is no drive error between the respective flow shunt valves 35 to 40 due to the driving of the 62a to 62f, and a drive error between the respective flow shunt valves 35 to 40 due to the pressure loss of the pipelines 51a to 51f. Without these, excellent composite operability can also be obtained.

In the first embodiment, the drive detector 80a
Solenoid valves 62a to 62f corresponding to the signals output from
Are driven, but such drive detectors 80a to 80f are not provided, and the six electromagnetic valves 62a
6262f is simply provided with one solenoid valve, and the shunt compensation valve 3
The same control pressure can be applied to each of the other driving units 35b to 40b of 5 to 40. In the case of such a configuration, the split ratio of the flow rates supplied to the respective directional control valves 29 to 34 via the respective split flow compensation valves 35 to 40 is uniquely set, that is, the first embodiment described above. Although it is not possible to change the shunt ratio according to the type of operation as in the example, it is possible to perform a specific operation such as excavation with a relatively simple structure.

FIG. 3 is an explanatory view showing a main part of a second embodiment of the present invention. In the second embodiment, a main hydraulic pump 22 comprising a variable displacement hydraulic pump is provided, and a flow control means for controlling a flow rate discharged from the main hydraulic pump 22 is provided with a displacement of the main hydraulic pump 22. The control actuator 41 is controlled by a pressure difference ΔP _LS between a pump pressure guided through a pipe 43 and a maximum load pressure guided through a pipe 44 to control the control actuator 41 described above. It is constituted by a flow control valve 42 to be controlled. Other configurations are the same as those of the first embodiment. Also in the first embodiment configured as described above, it is possible to perform control in accordance with the differential pressure ΔP _LS, that is, the load sensing compensation pressure determined by the force of the spring that biases the flow regulating valve 42. The same effect as that of the first embodiment is obtained.

FIG. 4 is an explanatory view showing a main part of a third embodiment of the present invention.

Also in the third embodiment, the configuration of the flow control means for controlling the displacement of the main hydraulic pump 22 is different from that of the first embodiment shown in FIG. The flow control means in the third embodiment includes an electromagnetic valve 64 connected to a hydraulic pressure source 63 and communicated between the head side and the rod side of the control actuator 41, and a solenoid valve 64 and a tank. And a solenoid valve 65 connected to the head side of the control actuator 41, and connected to a differential pressure detecting device 53 for detecting a differential pressure ΔP _LS between the pump pressure and the maximum load pressure. Control device including unit 66, arithmetic unit 67, storage unit 68, and output unit 69
Includes 70 and.

In this flow control means, the storage unit 68 of the control device 70 corresponds to the differential pressure between the desired pump pressure and the maximum load pressure in advance, that is, the spring pressure of the spring for urging the flow control valve 42a of FIG. The differential pressure is set, and the set differential pressure is compared with a value detected by the differential pressure detecting device 53 in an arithmetic unit 67, and a drive signal corresponding to the difference is obtained in the arithmetic unit 67. The output unit 69 selectively outputs to the drive units of the solenoid valves 64 and 65.

Here, the differential pressure ΔP _LS temporarily detected by the differential pressure detecting device 53
Is larger than the set differential pressure, a signal is output from the control device 70 to the drive unit of the solenoid valve 64, the solenoid valve 64 is switched to the lower position, and the pressure oil of the hydraulic power source 63 is moved to the head side of the control actuator 41. And the rod side. At this time, due to the pressure receiving area difference between the head side and the rod side of the control actuator 41, the piston of the control actuator 41 moves to the left in the drawing, and the displacement is changed so that the flow rate discharged from the main hydraulic pump 22 decreases. And the differential pressure ΔP _LS
Is controlled so as to approach the set differential pressure. When the differential pressure ΔP _LS detected by the differential pressure detecting device 53 is smaller than the set differential pressure, a signal is output from the control device 70 to the drive section of the solenoid valve 65, and the solenoid valve 65 is switched to the lower position. ,
The head side of the control actuator 41 communicates with the tank, the pressure oil of the hydraulic pressure source 63 is supplied to the rod side of the control actuator 41, the piston of the control actuator 41 moves rightward in the drawing, and the main hydraulic pump 22 The displacement is changed so that the flow rate discharged from the nozzle increases, and the pressure difference ΔP _LS is controlled so as to approach the set pressure difference. Other configurations are the same as those of the first embodiment.

In the second embodiment configured as described above, control by the load sensing compensation pressure can be performed in the same manner as in the first embodiment, and an effect equivalent to that of the first embodiment can be obtained.

FIG. 5 is an explanatory view showing a main part of a fourth embodiment of the present invention.

This fourth embodiment also differs from the first and second embodiments in the configuration of the flow control means for controlling the displacement of the main hydraulic pump 22. The flow control means in the third embodiment includes, for example, a hydraulic source 63, solenoid valves 64 and 65, an input unit 66, a calculation unit 67, and a storage unit equivalent to those in the second embodiment.
68, a main hydraulic pump including a control device 70 including an output unit 69
Displacement amount detection means for controlling the discharge amount of the main pump 22, detecting a displacement angle that determines the displacement of the main hydraulic pump 22, and outputting a displacement angle signal to the input unit 66 of the control device 70. And a command device 72 for outputting a signal for commanding the target flow rate of the main hydraulic pump 22, that is, the target tilt angle, to the input unit 66 of the control device 70.

In this flow control means, the value of the command signal by the operation of the command device 72 and the value detected by the tilt angle detector 71 are controlled by the control device.
The calculation unit 67 of 70 compares the signals, and a drive signal corresponding to the difference is selectively output from the output unit 69 to the drive units of the solenoid valves 64 and 65,
The flow rate according to the operation amount of the command device 72 is output from the main hydraulic pump 22. Other configurations are the same as those of the first embodiment.

In the fourth embodiment, the flow rate of the main hydraulic pump 22 can be determined without depending on the load sensing compensation pressure. Other effects are the same as those of the first embodiment.

<Effect of the Invention> The hydraulic drive device for civil engineering and construction machinery of the present invention is configured as described above, so that a stable drive of the shunt compensating valve can be obtained irrespective of a change in the tank pressure. Excellent control accuracy can be ensured, and there is almost no drive error between the shunt compensating valves, so it has excellent combined operability.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a hydraulic drive system for a civil engineering and construction machine according to the present invention.
FIG. 2 is a circuit diagram showing an embodiment of FIG.
FIG. 3 is a diagram showing a functional relationship set corresponding to a shunt compensating valve relating to a turning direction control valve provided in the second embodiment; FIG. 3 is an explanatory diagram showing a main part of a second embodiment of the present invention; FIG. 4 is an explanatory view showing a main part of a third embodiment of the present invention, FIG. 5 is an explanatory view showing a main part of a fourth embodiment of the present invention, and FIG. It is a circuit diagram showing a hydraulic drive. 21 ... Motor, 22, 22a ... Main hydraulic pump, 23 ... Swing motor, 24 ... Left running motor, 25 ... Right running motor, 26
... boom cylinder, 27 ... arm cylinder, 28 ... bucket cylinder, 29 ... turning direction control valve, 30 ... left traveling direction control valve, 31 ... right traveling direction control valve, 32 ... Directional control valve for boom, 33 ... Directional control valve for arm, 34 ...
Bucket directional control valve, 35, 36, 37, 38, 39, 40 ... Dividing compensation valve, 35a, 36a, 37a, 38a, 39a, 40a ... One drive unit, 35b, 36b, 37b, 38b, 39b 40b, the other drive unit, 41, a control actuator, 42, 42a, a flow control valve, 43a, 44, 44a, 51a, 51b, 51c, 51d, 51e, 51f,
61c ... pipeline, 52 ... control force applying means, 53 ... differential pressure detecting device, 55, 66 ... input unit, 56, 67 ... arithmetic unit, 57, 68 ...
... storage unit, 58, 69 ... output unit, 59 ... controller, 60
a …… Control pressure generator, 61a …… Pilot pump, 61
b ... Relief valve, 62a, 62b, 62c, 62d, 62e, 62f, 6
4, 65: Solenoid valve, 63: Hydraulic source, 70: Control device, 71
…… Tilt angle detector, 72 …… Command device, 80a, 80b, 80c, 8
0d, 80e, 80f: Drive detector.

Claims (6)

(57) [Claims] 1. A main hydraulic pump, a plurality of actuators driven by hydraulic oil supplied from the main hydraulic pump, a flow control valve for controlling a flow of hydraulic oil supplied to the actuators, And a flow control means for controlling a flow rate discharged from the main hydraulic pump, wherein the hydraulic oil of the main hydraulic pump is supplied to the flow control valve and the flow control valve. In the hydraulic drive device of the civil engineering / construction machine capable of supplying a combined drive of these actuators to each of the actuators through each of Pressure supply means for supplying the same pilot relief pressure so as to operate in the opening direction, and the other drive of each of the shunt compensation valves is provided. The moving part is provided with a control force applying means for giving a control force so that these branch flow compensating valves operate in the closing direction. The pilot pressure supply means includes a pilot pump, and a magnitude of a pilot pressure discharged from the pilot pump. The pilot pump included in the pilot pressure supply means, and a relief valve that regulates the flow rate of the pilot pump. A hydraulic drive device for a civil engineering / construction machine, wherein the control force applying means is provided on a pipe side communicating with each of the other drive units. 2. The flow rate discharged from the main hydraulic pump is
The civil engineering / construction machine according to claim 1, further comprising a flow control means for controlling the pressure in accordance with a pressure difference between a pressure of the hydraulic oil discharged from the main hydraulic pump and a maximum load pressure of the actuator. Hydraulic drive. 3. A commanding device for commanding a target flow rate of the main hydraulic pump, wherein the flow rate control means controls a discharge rate of the main hydraulic pump in accordance with a signal output from the commanding device. The hydraulic drive device for a civil engineering / construction machine according to claim 1, further comprising: 4. A main hydraulic pump, a plurality of actuators driven by pressurized oil supplied from the main hydraulic pump, a flow control valve for controlling a flow of the pressurized oil supplied to these actuators, And a flow control means for controlling a flow rate discharged from the main hydraulic pump, wherein the hydraulic oil of the main hydraulic pump is supplied to the flow control valve and the flow control valve. In the hydraulic drive device of the civil engineering / construction machine capable of supplying a combined drive of these actuators to each of the actuators through each of Pressure supply means for supplying the same pilot relief pressure so as to operate in the opening direction, and the other drive of each of the shunt compensation valves is provided. The moving portion is provided with control force adding means for giving a control force so that these branch flow compensating valves operate in the closing direction, and the control force adding means is configured to control the pressure of the pressure oil discharged from the main hydraulic pump and the pressure of the actuator. A differential pressure detecting device that detects a differential pressure between the maximum load pressure and a controller that is connected to the differential pressure detecting device and has a storage unit that stores a functional relationship between the differential pressure and the control force in advance; Control pressure generating means for generating a control pressure applied to the other drive unit of the shunt compensating valve provided corresponding to the actuator in accordance with the control force signal provided by the actuator. . 5. The control pressure generating means includes a pilot pump, and an electromagnetic valve arranged between the pilot pump and a driving portion of the flow compensating valve and operated in accordance with a control signal output from a controller. The hydraulic drive device for a civil engineering / construction machine according to claim 4, wherein: 6. The apparatus according to claim 5, wherein a plurality of the solenoid valves are provided corresponding to each of the plurality of flow compensating valves.
Hydraulic drive for civil engineering and construction machinery as described.