JPH0289803A - Hydraulically-operated device for civil engineering construction equipment - Google Patents

Abstract

PURPOSE:To stabilize drive of a flow division compensating valve and to improve composite operability by a method wherein a pilot relief pressure having the same opening direction is fed to the drive part of the one of flow division compensating valves, and a control force in a closing direction is exerted on the other drive part. CONSTITUTION:Flow division compensating valves 35-40 are provided on the inflow side of direction control valves 29-34 to control an oil pressure fed to actuators 23-28. An oil pressure from a pilot pump 61a and a relief valve 61b is introduced in an opening direction through a piping 61c to the one drive parts 35a-40a thereof. The pressures of solenoid valves 62a-62f actuated by means of signals (a)-(f) from a controller 59 are introduced in a closing direction to the other drive parts 35b-40b. A signal from a detecting device 53 for a differential pressure between the output oil pressure of a main hydraulic pump 22a and maximum load pressures of the actuators 23-28 is inputted to the controller 59. This constitution stabilizes working of the flow division compensating valves 35-40 despite of a change in a tank pressure, and enables ensurance of excellent control precision and composite operability.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is a system for dividing pressure oil of a main hydraulic pump through a plurality of division compensation valves to each of actuators provided corresponding to the division compensation valves. The present invention relates to a hydraulic drive system for civil engineering and construction machinery that can perform desired combined operations by supplying these actuators and driving these actuators in a combined manner.

<Prior Art> FIG. 6 is a circuit diagram showing a hydraulic drive system for a hydraulic excavator, which is cited as an example of a conventional hydraulic drive system for civil engineering and construction machines of this type.

The hydraulic drive device shown in FIG. 6 includes a prime mover 1, a variable displacement hydraulic pump, that is, a main hydraulic pump 2, which is driven by the prime mover 1, and a turning movement (not shown) that is driven by pressure oil discharged from the main hydraulic pump 2. It is equipped with a turning motor 3 that turns the body, and an actuator including a boom cylinder 4 that turns a boom (not shown).

In addition, the main hydraulic pump 2 controls the flow rate control valve that controls the flow of pressure oil supplied to the swing motor 3, that is, the swing direction control valve 5, and the differential pressure across the swing direction control valve 5. A flow rate control valve that controls the flow of pressure oil supplied from the main hydraulic pump 2 to the boom cylinder 4, that is, a boom directional control valve 7, and a front-back difference between the boom directional control valve 7. A branch compensating valve 8 for controlling pressure is provided.

One driving part 6a of the shunt compensation valve 6 is connected to the tank, and a control force Fal, which is the sum of the force of the spring 6C and the force due to the load pressure, is applied to the one driving part 6a. The other drive part 6b is given a control force Fa2 due to the downstream pressure of this branch compensation valve 6 and the maximum load pressure of the circuit led via the shuttle valve 9.10.
is applied so that the branch compensating valve 6 is closed. Similarly, one drive section 8a of the branch compensating valve 8 is connected to the tank, and this one drive section 8a receives a control force Fb, which is the sum of the force of the spring 8c and the force due to the load pressure. The branch compensation valve 8 is provided to open, and the other drive section 8b
A control force Fb2 based on the pressure on the downstream side of this branch compensating valve 8 and the maximum load pressure of the circuit is applied to close the branch compensating valve 8.

The displacement of the main hydraulic pump 2 is controlled by a control actuator 12 driven by a flow rate regulating valve 11 that 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.

When the actuator is driven independently (1), for example, when the swing direction control valve 5 is switched in order to drive the swing motor 3 to operate a swing structure (not shown), the pressure oil discharged from the main hydraulic ponder 2 is transferred to the branch compensation valve 6. , is supplied to the swing motor 3 via the swing directional control valve 5, but when a change occurs in the load pressure of the swing motor 3, the load pressure is guided to one drive part 6a of the branch compensation valve 6. As a result, the amount of throttling of the branch compensating valve 6 is adjusted as appropriate, and therefore the differential pressure across the swing direction control valve 5 is controlled to be kept constant. That is, the branch compensating valve 6 has a pressure compensating function. This also applies to the branch compensating valve 8 and the like related to the boom cylinder 4.

In addition, when the actuator is driven in a combined manner, for example, when the swing motor 3 and the boom cylinder 4, which have different driving pressures, are driven in combination, the swing direction control valve 5 and the boom direction control valve 7 can be operated to control the swing direction control valve 5 and the boom cylinder 4. When the required flow rate of the directional control valve 5 and the boom directional control valve 7, that is, the total allowable flow rate, is about to exceed the maximum capacity of the main hydraulic pump 2, it is determined by the self pressure of each actuator and the maximum load pressure of the circuit. The amount of restriction of the shunt compensation valve 6.8 is adjusted,
The flow rate guided to the swing directional control valve 5 and the flow rate guided to the boom directional control valve 7 are maintained at a constant flow rate, and the total of these flow rates does not exceed the maximum capacity of the main hydraulic pump 2. The differential pressure between the swing direction control valve 5 and the boom direction control valve 7 is maintained at the same level, and the main hydraulic pump 2
The pressure oil discharged from the pump can be divided and supplied to the swing motor 3 and the boom cylinder 4, thereby realizing combined operations such as swing and boom raising.

<Problems to be Solved by the Invention> By the way, in the above-described conventional hydraulic drive system for civil engineering and construction machinery, one drive section 6a, 8a of each of the flow compensation valves 6.8 is connected to the tank. Therefore, the flow compensation valve 6.
8 changes, and therefore it is difficult to obtain stable control accuracy.

In addition, since the shunt compensating valve 6.8 is driven by the force of the spring 6C18C, variations in manufacturing accuracy tend to occur between the springs 6C18C.
8, and therefore this spring 6C
Due to variations in the manufacturing accuracy of 18C, a situation may arise in which a desired split flow ratio cannot be obtained, and the combined operability may deteriorate.

The present invention has been made in view of the actual situation in the prior art described above, and its purpose is to obtain stable driving of the shunt compensating valves regardless of changes in tank pressure, and to minimize driving errors between the shunt compensating valves. The object of the present invention is to provide a hydraulic drive device for civil engineering and construction machinery that does not cause such problems.

Means for Solving the Problems To achieve this object, the present invention includes a main hydraulic pump, a plurality of actuators driven by pressure oil supplied from the main hydraulic pump, and a plurality of actuators driven by pressure oil supplied to these actuators. The main hydraulic pump is equipped with a flow rate control valve that controls the flow of pressure oil, a branch flow compensation valve that controls the differential pressure across these flow rate control valves, and a flow rate control means that controls the flow rate discharged from the main hydraulic pump. Hydraulic pump pressure oil, shunt compensation valve,
In a hydraulic drive system for civil engineering and construction machinery that supplies flow control valves to each actuator and is capable of combined driving of these actuators, one drive section of each of the flow compensation valves is supplied with flow compensation for these flow control valves. Providing a pilot pressure supply means for supplying the same pilot relief pressure so that the valves operate in the opening direction, and controlling the other driving section of each of the division compensation valves so that these division compensation valves operate in the closing direction. This configuration includes a control force adding means for applying force.

Function> As described above, the hydraulic drive system for civil engineering and construction machinery of the present invention is capable of supplying the same pilot relief pressure to one drive section of each of the plurality of branch compensating valves by the pilot pressure supply means. Because of this, these diverter compensation valves can be driven without being affected by tank pressure in any way.
Therefore, stable driving of the branch compensating valve can be obtained regardless of changes in tank pressure. Further, since the branch flow compensation valves can be driven without intervening spring force, and since the plurality of branch flow compensation valves are driven by the same pilot relief pressure, there is almost no driving error between the branch flow compensation valves.

<Example> Hereinafter, a hydraulic drive system for civil engineering/construction machinery according to the present invention will be explained based on the drawings.

FIG. 1 shows the first hydraulic drive system for civil engineering and construction machinery of the present invention.
It is a circuit diagram showing an example of. This first embodiment is applied to a hydraulic excavator, and includes a prime mover 21, a constant capacity hydraulic pump driven by the prime mover 21, that is, a main hydraulic pump 22a, and a hydraulic oil pump 22a driven by the pressure oil discharged from the main hydraulic pump 22a. a plurality of actuators, namely, a swing motor 23, a left travel motor 24, a right travel motor 25, a boom cylinder 26, and an arm cylinder 2.
7 and a packet cylinder 28. Note that the swing motor 23 drives a swinging body (not shown), the left running motor 24 and the right running motor 25 drive crawlers (not shown),
Boom cylinder 26, arm cylinder 27, and packet cylinder 28.

Each drives a boom, arm, and packet (not shown).

Also, a flow control valve, that is, a swing direction control valve, controls the flow of pressure oil supplied to each of the swing motor 23, left travel motor 24, right travel motor 25, boom cylinder 26, arm cylinder 27, and packet cylinder 28. 29
, left travel direction control valve 30, right travel direction control valve 31,
Boom directional control valve 32, arm directional control well 33, packet directional control valve 34, and branch flow compensation valves 35, 36, 37, 38, 3 provided corresponding to these flow rate control valves.
9.40.

Moreover, the displacement volume of the main hydraulic pump 22a mentioned above is
It is controlled by a flow rate control means, that is, the miscarriage regulating valve 42a, which is driven according to the differential pressure Δpts between the pump pressure led through the pipe line 43a and the maximum load pressure led through the pipe line 44a.

In addition, one of the driving parts 35a to 40a of each of the above-described branch compensation valves 35 to 40 is provided with the branch compensation valves 35 to 40, respectively.
40 is provided with a pilot pressure supply means for supplying the same pilot relief pressure so as to operate in the opening direction,
This pilot pressure supply means includes, for example, a pilot pump 61a, a relief valve 61b that regulates the magnitude of pilot pressure discharged from the pilot pump 61a, and one of the pilot pump 61a and the branch compensation valves 35 to 40. The configuration includes a conduit 61c that communicates with the drive units 35a to 40a.

Furthermore, a control force adding means 52 is provided to the other driving portion 35b to 40b of each of the branch compensating valves 35 to 40, which applies a control force so that the branch compensating valves 35 to 40 operate in the closing direction. The control force adding means 52 includes, for example, a differential pressure detecting device 53 that detects a differential pressure Δpts between the pressure of the pressure oil discharged from the main hydraulic pump 22a and the maximum load pressure of the actuator, and is connected to the differential pressure detecting device 53. and a controller 59 having a storage section 57 that stores the functional relationship between the differential pressure and the control force in advance, an input section 55, a calculation section 56, and an output section 58, and a control force signal output from the controller 59. The other driving portion 35b of the branch compensation valves 35 to 40 provided corresponding to the actuators
40b, and a control pressure generating means 60a for generating a control pressure applied to the control pressure 40b.

The above-mentioned control pressure generating means 60a includes the branch compensation valves 35 to
6 solenoid valves 62 provided corresponding to each of the 40
a, 62b, 62c, 62d, 62e, 62f, the above-mentioned pie four pump 61a that supplies pilot pressure to these solenoid valves 62a to 62f, and the magnitude of the pilot pressure output from this pilot pump 61a. The configuration includes the above-mentioned relief valve 61b that defines the above-mentioned relief valve 61b. Note that the solenoid valve 62a and the drive section 35b of the branch compensation valve 35
is connected to the solenoid valve 62b via the conduit 51a.
~62f and the drive unit 3 of the shunt compensation valves 36 to 40
6b to 40b are connected to each other via conduits 51b to 51f, respectively. In addition, solenoid valves 62a to 6
2f is adapted to be driven in accordance with each of the drive signals a, b, c, d, e, f output from the output section 58 of the controller 59, and the drive section of these solenoid valves 62a is , the return back pressure of the relief valve 61b is received as a common back pressure. Of the components of the control pressure generating means 60a, the parts including the relief valve 61b and the electromagnetic valves 62a to 62f are formed into one horizontal block as shown by the two-dot chain line, and the pipe line 5
The length dimensions of 1a to 51f are set to substantially the same length dimensions. In addition, due to the above-mentioned blocking, the lengths of the pipes 61c connected to one drive section 35a to 40a of each of the branch compensating valves 35 to 40 are also set to approximately the same length.

The storage unit 57 of the controller 59 stores, for example, the functional relationship between the differential pressure Δpts and the control force F as shown in FIG. A characteristic line in which the control force F decreases proportionally in response to
Corresponding to the branch compensating valves 36 to 40 related to the arm cylinder 27 and the packet cylinder 28, the characteristic lines shown in FIG.
The functional relationships with each other are individually stored. The slope of each characteristic line described above is set in consideration of the combination of actuator speeds suitable for performing various tasks.

Further, in this embodiment, an operation detection means for detecting which actuator is about to be driven is provided, for example, corresponding to each of the directional control valves 29 to 34, and detects the driving of these directional control valves 29 to 34. Drive detectors 80a, 80b, 8 that output signals to the controller 59
0c, 80d, 80e, and 80f are provided.

In the first embodiment configured as described above, when the actuator is driven alone, for example, when the two swing direction control valves are switched in order to drive the swing motor 23, the drive detector 80a It is detected that the two turning direction control valves have been operated, and in response to the signal, the functional relationship shown in FIG. The control force F is determined from the functional relationship and the differential pressure ΔPL5 detected by the differential pressure detection device 53 and inputted to the calculation unit 56 via the input unit 55, and the control signal a corresponding to this control force F is electromagnetic. Valve 62a
output to the drive unit. As a result, the solenoid valve 62a operates by an amount corresponding to the control force F, and the control pressure obtained by appropriately adjusting the pilot pressure by the pilot pump 61a is guided to the other driving part 35b of the branch compensation valve 35 through the pipe 51a.
An attempt is made to operate this branch compensating valve 35 in the closing direction.

However, the pilot pressure from the pilot pump 61a mentioned above is guided as a constant pressure to one driving part 35a of the branch compensating valve 35 through the pipe line 61c so as to oppose the above-mentioned control pressure, and this branch compensating valve 35 is opened. Try to operate in the direction. Therefore, the first branch flow compensation valve 35 has its throttle amount adjusted according to changes in the load pressure of the swing motor 23 and changes in the differential pressure ΔPL5, which is the difference between the discharge pressure of the main hydraulic pump 22a and the load pressure. As a result, the differential pressure across the swing direction control valve 29 is kept constant, and a flow rate corresponding to the operation amount of the swing direction control valve 29 is supplied to the swing motor 23, thereby independently driving the swing motor 23 as desired. In other words, it is possible to make the rotating body (not shown) turn.

Furthermore, during combined drive of the actuator, for example, during combined drive of the swing motor 23 and the boom cylinder 26, signals from the drive detectors 80a and 80d are input to the calculation unit 56 via the input units 55 of the five controllers. The differential pressure ΔP detected by the differential pressure detection device 53 based on the signal of
The control force corresponding to the shunt compensating valve 35 and the control force corresponding to the shunt compensating valve 36 according to Ls are individually determined by the calculation section 56 of the controller 59, and the control force signal a is output from the output section 58 of the five controllers. The control force signal d is output to the solenoid valve 62d, and the control force signal d is output to the solenoid valve 62d.
2a and 62d are driven. Along with this, the shunt compensation valve 35
．． 38, a constant pilot pressure from a pilot pump 61a is introduced to one of the driving parts 35a and 38a, and the other driving part 35b of the branch compensating valve 35 is supplied with a solenoid valve 6.
2a, a control pressure corresponding to the control force F corresponding to the functional relationship shown in FIG. A control pressure is derived in accordance with the control force F corresponding to a characteristic line (not shown) with a different slope, and as a result, the flow compensation valve 35
．． 38 is adjusted appropriately, that is, the amount of restriction of the branch flow compensation valve on the side where the load pressure is lower is adjusted to be larger than the amount of restriction of the flow distribution compensation valve on the side where the load pressure is higher. 35 and the flow rate flowing to the boom directional control valve 38 are controlled such that the flow rate is a predetermined flow rate, and the total of these flow rates does not exceed the displacement volume of the main hydraulic pump 22a. The boom cylinder 26 can be driven in combination, and a desired combination of turning and boom operation can be performed.

Note that the combined actuator drive is not limited to the above-described combination of the swing motor 23 and the boom cylinder 26, and the same operation as described above is performed with any combination of actuators.

In the first embodiment configured in this way, the shunt compensation valve 35
Since the same pilot relief pressure is supplied to one drive unit 35a to 40a of each of the actuators 35a to 40 through the conduit 61c, the effect of changes in tank pressure due to oil returned from the actuator, etc. can be compensated for by the shunt flow. Valve 35-40
Therefore, the branch compensation valves 35 to 40 can be stably driven regardless of changes in tank pressure, and excellent control accuracy can be obtained.

Moreover, one drive part 35a-4 of the branch compensation valves 35-40
Diversion compensation valve 35~ without intervening spring force in 0a
40, and these branch compensating valves 35 to 40 are driven by the same pilot relief pressure.
Almost no driving error occurs between the flow compensating valves 35 to 40, a desired flow ratio is obtained, and excellent combined operability is obtained.

Also, the relief valve 61b and the solenoid valves 62a to 62f are connected to one
In addition, the pipes 61c connected to one of the driving parts 35a to 40a of each of the branch compensating valves 35 to 40 are set to have approximately the same length. There is no drive error between the branch compensating valves 35 to 40 due to pressure loss in the passage 61c, and this also provides excellent combined operability.

Furthermore, as described above, the relief valve 61b and the solenoid valve 62a
~62f are blocked as one structure,
The same relief valve 61b is used as the drive part of the solenoid valves 62a to 62f.
In addition, the pipes 51a to 51
Since the length dimensions of f are set to be almost the same, there is no drive error between the solenoid valves 62a to 62f, and therefore each branch compensating valve 35 due to the drive of these solenoid valves 62a to 62f. There is no driving error between the valves 35 to 40, and there is no driving error between the branch compensating valves 35 to 40 due to pressure loss in the pipes 51a to 51f. Provides ease of use.

Note that in the first embodiment, the drive detector 80a
The solenoid valve 62a corresponds to the signal output from ~80f.
It is configured to drive either of ~62f,
Such drive detectors 80a to 80f are not provided, and 6
Only one solenoid valve is provided instead of the two solenoid valves 62a to 62f, and the other drive parts 35b to 35b of the branch compensation valves 35 to 40 are provided.
40b can also be configured to apply the same control pressure to each. With this configuration,
Each direction control valve 29-3 via each branch compensation valve 35-40
Although the dividing ratio of the flow rate supplied to No. 4 is uniquely set, that is, it cannot be changed to an arbitrary dividing ratio depending on the type of work as in the first embodiment described above.
Specific operations such as excavation can be performed with a relatively simple structure.

FIG. 3 is an explanatory diagram showing the main part of the second embodiment of the present invention. In this second embodiment, a main hydraulic pump 22 consisting of a variable displacement hydraulic pump is provided, and a flow rate control means for controlling the flow rate discharged from the main hydraulic pump 22 is provided by displacing the main hydraulic pump 22. The control actuator 41 that controls the volume is driven by the differential pressure Δpts between the pump pressure led through the pipe line 43 and the maximum load pressure led through the pipe line 44 to control the above-mentioned control actuator 41. It is composed of a flow rate N regulating valve 42. The other configurations are the same as those of the first embodiment described above.

Even in the first embodiment configured in this way, the differential pressure ΔP
Control can be performed according to the load sensing compensation pressure determined by the force of the spring that biases the LS, that is, the flow rate adjustment valve 42, and the same effect as in the first embodiment described above can be achieved.

FIG. 4 is an explanatory diagram showing main parts of a third embodiment of the present invention.

This third embodiment also differs from the first embodiment shown in FIG. 1 in the configuration of the flow rate control means for controlling the displacement of the main hydraulic pump 22.

The flow rate control means in this third embodiment is a hydraulic power source 63.
and a solenoid valve 6-1 connected to and connected between the head side and the rod side of the control actuator 11, and a solenoid valve 64 connected to the opening of the tank and connected to the head side of the control actuator 41. and a solenoid valve 65 connected to the side, and a differential pressure Δpts between the pump pressure and the maximum load pressure.
The input section 66 is connected to the differential pressure detection device 53 that detects the
Control device 7 including a calculation section 67, a storage section 68, and six output sections
Contains 0.

In this flow rate control means, in the storage section 68 of the control device 70,
The differential pressure between the desired pump pressure and the maximum load pressure, that is, the differential pressure corresponding to the spring force of the spring that biases the flow rate regulating valve 42a in FIG. A calculation unit 67 compares the value detected at 53 with the value detected by the calculation unit 67, and a drive signal corresponding to the difference is determined by the calculation unit 67. This drive signal is sent from the output unit 69 to the solenoid valve 64.65.
is selectively output to the drive unit.

Here, if the differential pressure Δpt detected by the differential pressure detection device 53 is
When s is larger than the set differential pressure, a signal is output from the control device 70 to the drive section of the solenoid valve 64, and the solenoid valve 6.
4 is switched to the lower position, and pressure oil from the hydraulic source 63 is supplied to both the head side and the rod side of the control actuator 711. At this time, due to the difference in pressure receiving area 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 figure, and the main hydraulic pump 2
The displacement volume is changed so that the flow rate discharged from 2 is reduced, and the differential pressure Δpts is controlled to be small so that it approaches the set differential pressure. Further, when the differential pressure ΔPts detected by the differential pressure detection device 53 is smaller than the set differential pressure, the control device 7o outputs a signal 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, pressure oil from the hydraulic source 63 is supplied to the rod side of the control actuator 41, the piston of the control actuator 41 moves to the right in the figure, and the main hydraulic pump 22 The displacement volume is changed so that the flow rate discharged from the pump is increased, and the differential pressure Δpts is greatly controlled so as to approach the set differential pressure. The other configurations are the same as those of the first embodiment described above.

Even in the second embodiment configured in this manner, control using the load sensing compensation pressure can be performed in the same way as in the first embodiment, and the same effects as in the first embodiment can be achieved.

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

This fourth embodiment also differs from the first and second embodiments in the configuration of the flow rate control means for controlling the displacement of the main hydraulic pump 22. The flow control means in this third embodiment includes, for example, a hydraulic power source 63, electromagnetic valves 64 and 65, an input section 66, and a calculation section 6, which are the same as those in the second embodiment described above.
7. It is equipped with a discharge amount control means for controlling the discharge amount of the main hydraulic pump 22, which is composed of a control device 70 including a storage section 68 and an output section 69, and detects a tilt angle that determines the displacement of the main hydraulic pump 22. , a tilt angle detector 71 that outputs a tilt angle signal to the input section 66 of the control device 70, and a signal that commands the target miscarriage of the main hydraulic pump 22, that is, the target tilt angle, to the input section 66 of the control device 70. A command device 72 is provided.

In this flow rate control means, the value of the command signal generated by the operation of the discussion device 72 and the value detected by the tilt angle detector 71 are compared in the arithmetic unit 67 of the control device 70, and a drive signal is generated according to the difference. is selectively output from the output section 69 to the driving section of the electromagnetic valves 64 and 65, and a flow rate corresponding to the operation amount of the command device 72 is output from the main hydraulic pump 22. The other configurations are the same as those of the first embodiment described above.

In this fourth embodiment, FElt of the main hydraulic pump 22 can be determined without depending on the load sensing compensation pressure. The effect of the pond is the same as in the first embodiment.

<Effects of the Invention> The hydraulic drive system for civil engineering and construction machinery of the present invention is configured as described above, so that stable drive of the diversion compensation valve can be obtained regardless of changes in tank pressure, and therefore, It is possible to ensure excellent control accuracy, and there is almost no drive error between the branch compensating valves, so it has excellent combined operability.

[Brief explanation of drawings]

FIG. 1 shows the first hydraulic drive system for civil engineering and construction machinery of the present invention.
FIG. 2 is a circuit diagram showing an embodiment of the first embodiment shown in FIG.
FIG. 3 is an explanatory diagram showing the main parts of the second embodiment of the present invention, and FIG. FIG. 4 is an explanatory diagram showing the main part of the third embodiment of the present invention, FIG. 5 is an explanatory diagram showing the main part of the fourth embodiment of the invention, and FIG. 6 is a diagram showing the main part of the fourth embodiment of the present invention. It is a circuit diagram showing a hydraulic drive device. 21... Prime mover, 22.22a... Main hydraulic pump, 23... Swing motor, 24...
...Left travel motor, 25...Right travel motor,
26...Boom cylinder, 27...Arm cylinder, 28...Packet cylinder, 2
1...Direction control valve for turning, 30...Direction control valve for left travel, 31...Direction control valve for right travel, 32...For boom Directional control valve, 33...
...Arm directional control valve, 34...Packet directional control valve, 35.36.37.38.39.40.
...Diversion compensation valve, 35a, 36a, 37a, 38
a, 39a, 40 a ----- One drive section, 3
5b, 36b, 37b, 38b, 39b, 40b...
...Other drive unit, 41...Control actuator, 42.42a...Flow rate adjustment valve, 43a
, 44.44a, 51a, 51b, 51c, 51d, 5
1e, 51f, 61C...Pipeline, 52...
... Control force adding means, 53... Differential pressure detection device,
55.66... Input section, 56.67...
- Arithmetic unit, 57.68... Storage unit, 58.69
...output section, five ...controllers,
60a... Control pressure generator, 61a...
・・Pilot pump, 6 l b ・・・・Relief valve, 62a, 62b, 62c, 62d, 62e, 62
f, 64.65--Solenoid valve, 63...Hydraulic pressure source, 70...Control device, 71...Tilt angle detector, 72...・Command device, 80a, 80b,
80c, 80d, 80e, 80f ・=-Drive detector. Figure 2 Figure 4 6d Figure 5 Figure 6

Claims (7)

[Claims] (1) A main hydraulic pump, a plurality of actuators driven by pressure oil supplied from this main hydraulic pump, a flow rate control valve that controls the flow of pressure oil supplied to these actuators, and their flow rates. It is equipped with a diversion compensation valve that controls the differential pressure before and after the control valve, and a flow rate control means that controls the flow rate discharged from the main hydraulic pump. In a hydraulic drive system for civil engineering and construction machinery that is capable of combined driving of these actuators by supplying power to each of the above actuators through A pilot pressure supply means is provided for supplying the same pilot relief pressure so as to operate in the same direction, and a control force is applied to the other drive section of each of the branch compensating valves so that the branch compensating valves operate in the closing direction. A hydraulic drive device for civil engineering and construction machinery, characterized in that it is provided with means for applying control force. (2) A flow rate control means for controlling the flow rate discharged from the main hydraulic pump according to the pressure difference between the pressure of the pressure oil discharged from the main hydraulic pump and the maximum load pressure of the actuator. A hydraulic drive device for civil engineering/construction machinery according to claim (1). (3) The flow rate control means includes a command device that commands a target flow rate of the main hydraulic pump, and a discharge amount control means that controls the discharge amount of the main hydraulic pump in accordance with a signal output from the command device. A hydraulic drive device for civil engineering/construction machinery according to claim (1). (4) The pilot pressure supply means is a pilot pump,
Claim (1) characterized in that it includes a relief valve that regulates the magnitude of the pilot pressure discharged from the pilot pump, and a pipe line that connects the pilot pump and the drive section of one of the branch compensating valves. 1) Hydraulic drive device for civil engineering and construction machinery described above. (5) the control force adding means is connected to a differential pressure detection device that detects a differential pressure between the pressure of the pressure oil discharged from the main hydraulic pump and the maximum load pressure of the actuator, and the differential pressure detection device;
A controller has a memory unit that stores the functional relationship between differential pressure and control force in advance, and a control force signal output from the controller is applied to the other drive unit of the shunt compensation valve provided corresponding to the actuator. 2. The hydraulic drive system for civil engineering and construction machinery according to claim 1, further comprising a control pressure generating means for generating a control pressure. (6) The control pressure generating means includes a pilot pump and a solenoid valve that is disposed between the pilot pump and the drive section of the branch compensation valve and operates in response to a control force signal output from the controller. A hydraulic drive device for civil engineering/construction machinery according to claim (5). (7) The hydraulic drive system for civil engineering and construction machinery according to claim (6), characterized in that a plurality of solenoid valves are provided corresponding to each of the plurality of branch compensation valves.