JP2711178B2 - Hydraulic drive for civil and construction machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic drive device for civil engineering and construction equipment such as a hydraulic shovel, and in particular, an arm that responds to hydraulic oil of a hydraulic pump via a plurality of pressure compensating valves and a flow control valve. The present invention relates to a hydraulic drive device for a civil engineering / construction machine that divides and supplies a plurality of actuators each including a cylinder and a boom cylinder to perform a combined drive thereof to perform a desired combined operation.

BACKGROUND ART There is a hydraulic shovel as an example of a civil engineering / construction machine that performs a combined drive of a plurality of actuators including an arm cylinder and a boom cylinder to perform a desired combined operation. The hydraulic shovel includes a lower traveling body for moving the hydraulic shovel, an upper revolving body pivotally mounted on the lower traveling body, and a front mechanism including a boom, an arm, and a bucket. Various facilities such as a cab, a prime mover, and a hydraulic pump are mounted on the upper revolving superstructure.
And a front mechanism is attached.

By the way, the hydraulic drive device used for this type of civil engineering and construction equipment has a pump discharge flow rate controlled so that the discharge pressure of the hydraulic pump is higher than the maximum load pressure of the plurality of actuators by a certain value, and the drive of the actuator is controlled. There is a system called a load sensing system that discharges a required flow rate from a hydraulic pump. This load sensing system typically responds to the discharge pressure of a hydraulic pump and the maximum load pressure of a plurality of actuators extracted in a detection line, as described in, for example, JP-A-60-11706. And a pump regulator having a switching cylinder that operates and controls the supply and discharge of pressure oil, and an operation cylinder that is driven by the pressure oil controlled by the switching valve and changes the displacement of the hydraulic pump. I have. The switching valve is provided with a spring for biasing the switching valve in a direction opposite to the pressure difference between the pump discharge pressure and the maximum load pressure. In this pump regulator, when the maximum load pressure rises, the switching valve operates to drive the working cylinder, thereby increasing the displacement of the hydraulic pump, thereby increasing the pump discharge flow rate and increasing the pump discharge pressure. As a result, the pump discharge pressure is controlled to be higher than the maximum load pressure by a specified value determined by the spring.

In a load sensing system, a pressure compensating valve is generally disposed upstream of each flow control valve, so that a differential pressure across the flow control valve is maintained at a specified value determined by a spring of the pressure compensating valve. You. By arranging the pressure compensating valve in this way and maintaining the differential pressure across the flow control valve at a specified value, when a plurality of actuators are driven simultaneously, the differential pressure across the flow control valves for all of the actuators increases. The flow rate is kept at the specified value, so that the flow control can be accurately performed by all the flow control valves irrespective of the fluctuation of the load pressure, and the combined drive of the actuator can be stably performed at a desired drive speed.

Further, in the load sensing system described in JP-A-60-11706, instead of the spring of the pressure compensating valve,
Means are provided for loading the pump discharge pressure and the maximum load pressure in opposition, and the specified value is set by the pressure difference between the two. As described above, the pump discharge pressure and the maximum load pressure are maintained at specified values determined by the spring of the switching valve in the pump regulator. Therefore, the specified value as the target value of the differential pressure across the flow control valve can be set based on the differential pressure between the pump discharge pressure and the maximum load pressure, and stable combined driving of the actuator can be performed as described above.

When the differential pressure is used instead of the spring, the hydraulic pump saturates, and when the discharge flow rate becomes insufficient with respect to the required flow rate, the differential pressure between the pump discharge pressure and the maximum load pressure decreases. Since the same differential pressure is applied to all the pressure compensating valves, the differential pressure across all the flow control valves is uniformly kept at a value smaller than the normal specified value. As a result, when the pump discharge flow rate is insufficient, it is avoided that a large flow rate is preferentially supplied to the actuator on the low load side,
The pump discharge flow is divided at a ratio corresponding to the ratio of the required flow. That is, the pressure compensating valve exerts a branch flow compensating function even when the hydraulic pump is saturated. With this shunt compensation function,
Even when the hydraulic pump is saturated, the drive speed ratio of the plurality of actuators is appropriately controlled, and stable combined drive of the actuators is possible.

In addition, the pressure compensating valve installed so as to exert the shunt compensation function even when the hydraulic pump is saturated,
In this specification, it is referred to as a “shunt compensating valve” for convenience.

However, the above-described conventional hydraulic drive has the following problems.

In the work performed by the hydraulic excavator, in addition to the normal work of excavating earth and sand, the operation of rotating the arm toward the front, that is,
There is a specific operation including an arm cloud operation, for example, a horizontal pulling operation that combines the arm cloud and boom raising, and pulls the tip of the bucket horizontally toward the front to level the ground. In this horizontal pulling operation, first, the tip of the bucket is brought close to the ground by the arm cloud, and after the tip of the bucket touches the ground, the boom is rotated upward while performing arm cloud so that the bucket tip draws a trajectory parallel to the ground It is performed in the procedure of making it.

By the way, in a hydraulic drive of a hydraulic shovel, a hydraulic pump is one of expensive devices, and it is desirable that the capacity of the hydraulic pump be small from the viewpoint of manufacturing cost. It is preferable to set the flow rate to be smaller than the required flow rate of the flow control valve when the arm operation lever is operated at the full stroke. When the horizontal pulling operation is performed in the above-described procedure with the capacity of the hydraulic pump set as described above, the following problems occur.

That is, when the operating lever for the arm is operated to the full stroke in order to increase the operating speed of the arm first, the hydraulic pump reaches the maximum discharge flow rate, the entire flow rate is supplied to the arm cylinder, and the hydraulic pump is saturated. become. From such a state, when the boom operation lever is operated to operate the boom flow control valve for raising the boom, the hydraulic drive device described in Japanese Patent Application Laid-Open No. 60-11706 discloses a hydraulic drive device disclosed in JP-A-60-11706. The branch flow compensating function divides the pump discharge flow at a ratio corresponding to the ratio of the operation amount (required flow) of the operation lever, so that the boom cylinder can be driven. However, at this time, the flow rate supplied to the arm cylinder at the same time decreases, so that the operating speed of the arm cylinder becomes slower, and eventually the boom cylinder must be operated together with such a change in the operating speed of the arm cylinder. It requires careful and difficult operations, resulting in poor operability.

In addition, in order to eliminate the effect of such a change in the operating speed of the arm cylinder, it is possible to operate the arm operation lever with a small operation amount equal to or less than the full stroke in consideration of the flow rate flowing into the boom cylinder in advance. Although it is conceivable, in this case, since the stroke range of the operation lever is narrow, it is difficult to perform a delicate operation, and the operability deteriorates from a different viewpoint from the above.

Furthermore, since the operability in any of the above cases is deteriorated, the accuracy of the horizontal pulling work is likely to vary, and if it is attempted to prevent such a variation in accuracy, it takes time to work, and the work efficiency is improved. Unlikely.

In the above description, the horizontal pulling operation by the combined operation of the arm cloud operation and the boom raising has been described, but the bucket may be rotated together in the horizontal pulling operation, and when the bucket is also operated in this manner, the arm Since it is necessary to operate three operation levers for the boom and the bucket, the operation becomes more difficult, and the accuracy of the horizontal pulling operation further varies, which tends to lower the working efficiency.

The above is a case where the horizontal pulling work is referred to as an example of the specific work including the arm cloud operation.However, the same problem occurs in the specific work including other arm cloud operations, such as a slope work that forms a slope. is there.

An object of the present invention is to carry out a combined drive of a plurality of actuators without causing a change in the operating speed of an arm cylinder when performing a specific operation including an arm cloud operation, and to sufficiently operate an operating area of an arm operating lever. An object of the present invention is to provide a hydraulic drive device for civil engineering and construction machinery that can be increased in size.

DISCLOSURE OF THE INVENTION In order to achieve the above object, according to the present invention, a plurality of actuators including a hydraulic pump, an arm cylinder and a boom cylinder driven by pressurized oil supplied from the hydraulic pump, and supply to these actuators A plurality of flow control valves including a directional control valve for the arm and a directional control valve for the boom that respectively control the flow of the pressurized oil,
A plurality of diverting compensation valves that respectively control the differential pressures of the flow control valves; and the diverting compensating valves each include a driving unit that sets a target value of the differential pressure of the corresponding flow control valves. In a hydraulic drive for a construction machine, a first means for detecting an arm cloud operation by driving the arm cylinder, and a differential pressure across a flow control valve associated with at least the arm cylinder when the arm cloud operation is detected. And a second means for controlling the driving means of the corresponding shunt compensating valve so as to reduce the target value.

Since the present invention is configured as described above, when a specific work requiring the arm cloud operation is performed,
The first means detects this, and the second means controls the driving means of the corresponding diversion compensating valve so that at least the target value of the differential pressure across the flow control valve associated with the arm cylinder decreases. Thus, the flow rate supplied to the arm cylinder is adjusted to a smaller flow rate than during normal operation, and combined driving without causing a speed change of the arm cylinder is enabled. Further, the ratio of the flow rate passing through the arm flow control valve to the lever stroke is smaller than that in the normal operation, and therefore, the operation area of the lever in which the flow rate can be changed can be made sufficiently large.

Preferably, the second means includes, when the arm cloud operation is detected, a target value of a differential pressure across the flow control valve related to the arm cylinder and a target value of a differential pressure across the flow control valve related to the boom cylinder. The driving means of each of the flow compensating valves is controlled so as to decrease both the target value and the target value.

Also preferably, the second means is operated in accordance with which of a normal operation and a specific operation including an arm cloud operation is performed, and includes means for outputting a corresponding selection signal, wherein the selection signal is an arm operation. When the signal corresponds to a specific operation including a cloud operation, the control of the driving means of the shunt compensation valve is executed.

More preferably, the second means is means for detecting a differential pressure between the discharge pressure of the hydraulic pump and the maximum load pressure of the plurality of actuators, and is set in advance corresponding to a specific operation including an arm cloud operation. The differential pressure and the first
Means for storing a first functional relationship between the differential pressure and the second control force, which is set in advance corresponding to a normal operation, and the arm cloud operation, If not detected, the second control force corresponding to the differential pressure is obtained from the detected differential pressure and the second functional relationship, and the drive of the shunt compensating valve is performed so that the second control force is generated. Means for controlling the means, and when the arm cloud operation is detected, the first control force corresponding to the differential pressure is obtained from the detected differential pressure and the first functional relationship. The driving means of the shunt compensating valve is controlled so as to generate the flow.

Also preferably, the second means calculates a control force to be generated by the drive means of the shunt compensating valve and outputs a corresponding control force signal; and a control calculated based on the control force signal. Control pressure generating means for generating a control pressure according to the force.

Also preferably, the control force generating means includes a pilot hydraulic pressure source and an electromagnetic proportional valve that generates the control pressure based on the hydraulic pressure source.

Also preferably, the flow control valve related to the arm cylinder is a pilot-operated valve driven by pilot pressure, and the first means detects the pilot pressure for driving the arm cylinder in the extension direction. It is.

Also preferably, the driving means of the shunt compensating valve includes a single driving unit for generating a control force to drive the shunt compensating valve in the valve opening direction, and the second means includes a unit for controlling the arm cloud operation. The control force generated by the drive unit when detected is made smaller than usual.

The drive means of the shunt compensation valve may be configured to include a spring that drives the shunt compensation valve in the valve opening direction, and a drive unit that generates a control force and drives the shunt compensation valve in the valve closing direction. In this case, the second means makes a control force generated by the drive unit when the arm cloud operation is detected larger than usual.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a hydraulic shovel equipped with a hydraulic drive device of the present invention.

FIG. 2 is a sectional view showing a horizontal pulling operation performed by the excavator.

FIG. 3 is a schematic diagram of a hydraulic drive device according to one embodiment of the present invention.

FIG. 4 is a diagram showing details of a pump regulator of the hydraulic drive device.

FIGS. 5, 6, and 7 are diagrams showing a functional relationship between the control force stored in the storage unit of the controller of the hydraulic drive device shown in FIG. 3 and the load sensing differential pressure.

FIG. 8 is a flowchart showing a processing procedure in a controller of the hydraulic drive device shown in FIG.

FIG. 9 is a view showing the balance of the forces acting on the drive section of the branch flow compensation valve provided in the hydraulic drive apparatus shown in FIG.

FIG. 10 is a diagram showing characteristics obtained by the hydraulic drive device shown in FIG.

FIG. 11 is a schematic view of a hydraulic drive device according to another embodiment of the present invention.

FIGS. 12, 13, and 14 are diagrams showing a functional relationship between the control force and the load sensing differential pressure stored in the storage unit of the controller of the hydraulic drive device shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 10 by taking a hydraulic shovel as an example of a working machine.

Configuration As shown in FIG. 1, the hydraulic excavator rotates a boom 1, an arm 2, and a bucket 3 constituting a front, a boom cylinder 4 for rotating the boom 1, an arm cylinder 5 for rotating the arm 2, and a bucket 3. It is equipped with a bucket cylinder 6 for moving, and in addition to the usual work of excavating earth and sand,
As shown in FIG. 2, the arm 2 is rotated in the direction of arrow 7 and
The boom 1 is rotated in the direction of the arrow 8 and the tip of the bucket 3 is pulled horizontally in the forward direction as shown by the arrow 9 to level the ground and perform a horizontal pulling operation. The operation of rotating the arm 2 in the direction of the arrow 7 is called an arm cloud operation.

The hydraulic excavator is equipped with the hydraulic drive device of the present embodiment. The hydraulic drive device includes a prime mover 10 and a variable displacement hydraulic pump driven by the prime mover 10, that is, a main pump 11, and a flow of pressure oil supplied from the main pump 11 to the boom cylinder 4. , A boom directional control valve 12, a pressure compensating valve for controlling the pressure difference Pz2-P L2 across the boom directional control valve 12, ie, a diversion compensating valve 13, and a main pump. A flow control valve for controlling the flow of the pressure oil supplied from 11 to the arm cylinder 5, that is, an arm directional control valve 14, and a pressure for controlling the differential pressure Pz 1 -PL 1 of the arm directional control valve 14. Compensating valve,
That is, a flow compensating valve 15, a flow control valve for controlling the flow of pressure oil supplied from the main pump 11 to the bucket cylinder 6, that is, a bucket directional control valve 16, and a front-back difference between the bucket directional control valve 16. A pressure compensating valve for controlling the pressure Pz3-PL3, that is, a diversion compensating valve 17 is provided.

The flow control valve 12 has driving parts 12x, 12y connected to the pilot lines 12p1, 12p2, and the pilot lines 12p1, 12p2.
Is connected to an operating device 12b having an operating lever 12a for a boom. When the operation lever 12a is operated, the operation device 12b outputs a pilot pressure according to the operation amount to one of the pilot lines 12p1 and 12p2 according to the operation direction. The same applies to the flow control valves 14 and 16, and the driving section 14 is connected to the pilot lines 14 p1 and 14 p2 and 16 p1 and 16 p2.
x, 14y and 16x, 16y are connected, and pilot line 14 p1,
14 p2 and 16 p1, 16 p2 are connected to operating devices 14b, 16b having operating levers 14a, 16a for arms and buckets.

Detection flow lines 12c, 14c, 16c for extracting the load pressure of the boom cylinder 4, the arm cylinder 5, and the bucket cylinder 6 are connected to the flow control valves 12, 14, 16 respectively, and transmitted to the detection flow lines 12c, 14c. The higher one of the applied load pressures is selected by the shuttle valve 18 and output to the detection line 18a, and the higher one of the load pressures transmitted to the detection lines 16c and 18a, that is, Shuttle valve with load pressure Pamax
It is selected by 19 and output to the detection pipeline 19a.

The branch flow compensating valves 13, 15, 17 are connected to the load pressures (the pressures at the outlets of the corresponding flow control valves 12, 14, 16) extracted to the detection lines 12c, 14c, 16c via the lines 13a, 15a, 17a. ) Drive units 13x, 15x, 17 to which P L2, P L1, P L3 are guided to urge the diversion compensating valve in the valve opening direction
x and corresponding flow control valves 12, 1 via lines 13b, 15b, 17b
Drive units 13y, 15y, 17y for guiding the pressures Pz2, Pz1, Pz3 on the inlet side of 4, 16 to bias the branch flow compensating valve in the valve closing direction, and the pipelines 13c, 1
Drive units 13d, 15d, and 17 that control pressures Fc2, Fc1, and Fc3, which will be described later, are guided through 5c and 17c, and bias the branch flow compensation valve in the valve opening direction.
d. Drive units 13d, 15d, 17d are flow control valves 12,1
It is for setting the target values of the differential pressures P z2-P L2, P z1-P L1 and P z3-P L3 of the front and rear pressures of 4, 16 and the drive units 13x, 15x, 17
x and 13y, 15y, 17y are for feeding back the differential pressure before and after, and the control pressures Fc2, Fc are supplied to the driving units 13d, 15d, 17d.
By loading 1, Fc3, a corresponding control force is generated in these drive units, and the differential pressure across the flow control valves 12, 14, 16 is maintained at a value determined by the control force.

The main pump 11 has a displacement capacity variable mechanism (hereinafter, represented by a swash plate) 11a, and the amount of displacement (displacement volume) of the swash plate 11a is controlled by a load sensing type pump regulator 22.

As shown in FIG. 2, the pump regulator 22 is connected to the swash plate 11a of the main pump 11 and has an operating cylinder 22a for driving the swash plate 11a.
The bottom side chamber is connected to the pipe line 22b and the tank 20 via the first and second two switching valves 22c and 22d, and is connected to the discharge pipe line 11b of the main pump 11 via 22b. I have.

The first switching valve 22c is a switching valve for load sensing control, and a pump discharge pressure Ps is applied to a driving unit 22e on one side from a pipe 22b, and a detection pipe 19a is applied to a driving unit 22f on the other side.
The maximum load pressure Pamax selected by the shuttle valve 19 via
Is loaded. In addition, a spring 22g is provided on the drive unit 22f side of the switching valve 22c.

Assuming that the maximum load pressure Pamax selected by the shuttle valve 19 is the load pressure of the arm cylinder 5, when the load pressure increases, the switching valve 22c is driven to the left in the drawing, and the switching valve 2
2c connects the bottom chamber of the working cylinder 22a to the tank 20, whereby the working cylinder 22a is driven in the contraction direction, and the tilt amount of the swash plate 11a is increased. As a result, the discharge flow rate of the main pump 11 increases, and the pump discharge pressure Ps increases. When the pump discharge pressure increases, the switching valve 22c is returned to the right side in the figure, and the differential pressure between the pump discharge pressure and the load pressure is changed by the spring 22.
When reaching the specified value determined by g, the switching valve 22c stops,
The driving of the working cylinder 22a also stops. Conversely, when the load pressure decreases, the switching valve 22c is driven rightward in the drawing, and the switching valve 22c
Connects the bottom side chamber of the working cylinder 22a to the conduit 22b, whereby the working cylinder 22a is driven in the extension direction by the pressure receiving area difference between the bottom side chamber and the rod side chamber, and reduces the amount of tilt of the swash plate 11a. As a result, the discharge flow rate of the main pump 11 decreases, and the pump discharge pressure decreases. When the pump discharge pressure decreases, the switching valve 22c is returned to the left in the figure, and when the differential pressure between the pump discharge pressure and the load pressure reaches a specified value determined by the spring 22g, the switching valve 22c stops and the working cylinder 22a
Is also stopped. Thus, the pump discharge pressure is controlled to be higher than the load pressure of the arm cylinder 5 by a specified value determined by the spring 22g.

The second switching valve 22d is a switching valve that performs horsepower limiting control, and is configured as a servo valve that feeds back the tilt position of the swash plate 11a. Thus, when the pump discharge pressure increases and exceeds a predetermined value, the pump discharge flow rate is controlled so that the maximum possible discharge flow rate of the main pump 11 decreases as the discharge pressure increases.

Returning to FIG. 3, the hydraulic drive device of the present embodiment also includes a sensor for detecting the operation of the arm cylinder 5 in the extension direction, that is, the arm cloud operation, for example, the directional control valve 14 for the arm.
The arm cloud sensor 21 that detects a pilot pressure applied to the drive unit 14y and outputs an arm cloud detection signal Y, and a load that is a differential pressure between the pump discharge pressure Ps and the maximum load pressure Pamax among the load pressures of the actuators. Differential pressure sensor 23 that detects sensing differential pressure ΔP LS,
For example, there is provided a selection device 24 that is operated in accordance with a normal operation such as an excavation operation of earth and sand or a specific operation including an arm cloud operation, for example, a horizontal pulling operation, and outputs a corresponding selection signal X.

Further, the hydraulic drive device receives the detection signals Y and ΔP LS from the sensors 21 and 23 and the selection signal X from the selection device 24, and based on these signals, drives the shunt compensation valves 13, 15, and 17 based on these signals.
13d, 15d, controller 30 to calculate the control force F1, F2, F3 to be generated by 17d, and output a corresponding control force signal,
Control pressure generating means 31 for generating control pressures Fc1, Fc2, and Fc3 according to the control force calculated based on the control force signal is provided.

The controller 30 has an input unit 26, a storage unit 27, a calculation unit 28, and an output unit 29. The control pressure generating means 31 is driven in synchronization with the electromagnetic proportional valves 32, 33, and 34 connected to the drive units 13d, 15d, and 17d of the branch flow compensating valves 13, 15, and 17, respectively, and is driven in synchronization with the main pump 11. A pilot pump 35 that supplies pressure oil to each of the proportional valves 32, 33, and 34 is provided.

The arm cloud sensor 21, the differential pressure sensor 23, and the selection device 24 described above are connected to the input unit 26 of the controller 30, and the arm cloud signal Y, the load sensing differential pressure signal ΔP LS, and the selection signal X are input thereto. As shown in FIG. 5, the storage unit 27 stores a load sensing differential pressure ΔP LS set in advance corresponding to the branch flow compensating valve 15 related to the arm cylinder 5 and a control force F1 for controlling the branch flow compensating valve 15.
As shown in FIG. 6, a load sensing differential pressure ΔP LS set in advance corresponding to the shunt compensation valve 13 related to the boom cylinder 4 and a control force F2 for controlling the shunt compensation valve 13 as shown in FIG. And a functional relationship between a load sensing differential pressure ΔP LS set in advance corresponding to the bucket cylinder 6 and a control force F3 for controlling the shunt compensation valve 17 as shown in FIG. ing.

In FIG. 5, FIG. 6 and FIG. 7, characteristic lines 39, 40 and 41 shown by solid lines indicate specific operations including arm cloud operation,
That is, it is the first functional relationship set in relation to the arm cloud operation of the horizontal pulling operation, and the characteristic lines 36, 37,
Reference numeral 38 denotes a second functional relationship set in relation to the normal work, and characteristic lines 42, 43, and 44 indicated by dashed lines indicate a third functional relationship set in relation to the arm dump operation of the horizontal pulling work. .

In this embodiment, the control force F generated by the driving units 15d, 13d, 17d
Since 1, F2 and F3 act in the valve opening direction, the relationship is set such that the control forces F1, F2 and F3 decrease as the load sensing differential pressure ΔPLS decreases. Further, when the arm dumping operation of the horizontal pulling operation is performed, the direction control valve for the arm is used.
14.Boom directional control valve 12 and bucket directional control valve
The slopes of the characteristic lines 42, 43, and 44 showing the third functional relationship are set to be large so that the target value of the differential pressure of 16 becomes the maximum and the flow rate for driving each actuator at the maximum speed can be supplied. During normal operation, the target value of the differential pressure across the directional control valves 14, 12, 16 is slightly smaller than its maximum target value, and the flow rate at which each actuator is driven at a speed slightly smaller than its maximum speed. The slopes of the characteristic lines 36, 37, and 38 indicating the second functional relationship are set to be relatively large but slightly smaller than the slopes of the characteristic lines 42, 43, and 44 indicating the third functional relationship so that can be supplied. In addition, the target value of the differential pressure across the directional control valves 14, 12, 16 is minimized during the arm cloud operation of the horizontal pulling operation, and at least the arm cylinder 5 has at least the arm cylinder 5 at the time of combined driving with the boom cylinder 4 and the bucket cylinder 6. By other actuators The slopes of the characteristic lines 39, 40, 41 showing the first functional relationship are the same as those of the characteristic lines 36, 37, 38 showing the second functional relationship, so that a moderately large flow rate can be supplied within a range in which the speed does not change. It is set smaller than the slope.

Further, the control force signal output from the output unit 29 of the controller 30 is given to each drive unit of the electromagnetic proportional valves 32, 33, and.

Operation The operation of the embodiment configured as described above will be described below with reference to the flowchart shown in FIG.

It is now assumed that the selection device 24 has selected a normal operation such as excavation of earth and sand. Along with this, the controller 30 performs the processing shown in FIG. That is, first, the procedure S1
, The load sensing differential pressure signal ΔP LS output from the differential pressure sensor 23, the selection signal X output from the selection device 24, and the detection signal Y output from the arm cloud sensor 21 Operation unit via input unit 26
Read to 28. Next, the procedure proceeds to step S2, where the calculation unit 28 determines whether or not the selection signal X corresponds to the horizontal pulling operation. Now, it is normal work, so this judgment is not satisfied,
Move on to step S3. In this step S3, the storage unit of the controller 30
27, the characteristic line 36 of the normal operation corresponding to the shunt compensation valve 15 of the arm cylinder 5 in FIG. 5, and the shunt compensation valve of the boom cylinder 4 in FIG. The characteristic line 37 of the normal operation corresponding to 13 and the characteristic line 38 of the normal operation corresponding to the shunt compensating valve 17 of the bucket cylinder 6 in FIG. 7 are read out to the calculation unit 28, and the load sensing differential pressure ΔP LS Are obtained for the control forces F1, F2, F3.

Next, the procedure proceeds to step S4 in FIG. 8, where the control force signals corresponding to the control forces F1, F2, and F3 obtained in step S3 are output from the output unit 29 to the drive units of the electromagnetic proportional valves 33, 32, and. In response to this, the electromagnetic proportional valves 33, 32, and 34 are opened appropriately, and the pilot pressure discharged from the pilot pump 35 is applied to these electromagnetic proportional valves 33, 3
Control pressure F c1, F by changing the size according to the opening of 2,34
Drive units 15d, 13d, 17 of the shunt compensation valves 15, 13, 17 as c2, F c3
d, these branch flow compensating valves 15, 13, 17 are driven in the valve opening direction by the aforementioned control forces F1, F2, F3. At this time, for example, a combined operation of a boom, an arm, and a bucket is intended,
When the operating levers 12a, 14a, 16a of the boom directional control valve 12, the arm directional control valve 14, and the bucket directional control valve 16 are operated, the flow rate discharged from the main pump 11 causes these diverting compensation valves 13, 15, 17, the boom cylinder 4, the arm cylinder 5, and the bucket cylinder 6 via the boom directional control valve 12, the arm directional control valve 14, and the bucket directional control valve 16.
The cylinders 4, 5, and 6 are operated to perform a combined drive of the boom, the arm, and the bucket, thereby performing a normal operation such as excavation of earth and sand.

At this time, for example, referring to FIG.
Considering the balance of the forces acting on the driving units 15x, 15y and 15d of the shunt compensation valve 15 according to the present invention, the pressure receiving area of the driving unit 15x is a L1, the pressure receiving area a z1 of the driving unit 15y, and the pressure receiving area of the driving unit 15d are If a s1 is assumed, the balance is P L1 · a L1 + F c1 · a s1 = P zl · a z1 (1) Here, for convenience, assuming that aL1 = az1 = as1, the pressure difference Pz1-PL1 across the arm directional control valve 14 becomes Pz1-PL1 = Fc1 (2). Here, the control pressure F c1 is a control pressure corresponding to the control force F1, that is, a control pressure that satisfies the characteristic line 36 of the second functional relationship. If the gradient of the characteristic line 36 is a proportional constant α, The expression (2) is expressed as the following expression (3).

P z1−P L1 = α · ΔP LS (3) Similarly, the balance of the forces acting on the drive units 13x, 13y, and 13d of the shunt compensating valve 13 related to the boom cylinder 4 is determined by setting the pressure receiving area of the drive unit 13x to a L2 , The pressure receiving area a z2 of the driving unit 13y, the driving unit 13d
If the pressure receiving area of the boom directional control valve 12 is assumed to be a s2, P L2 · a L2 + F c2 · a s2 = P z2 · a z2 (4) The differential pressure P z2 −P L2 becomes P z2 −P L2 = F c2 (5). If the gradient of the characteristic line 37 in FIG. 6 is a proportional constant β, P z2 −P L2 = β · ΔP LS (6)

Further, the balance of the forces acting on the driving portions 17x, 17y, 17d of the branch flow compensating valve 17 relating to the bucket cylinder 6 is such that the pressure receiving area of the driving portion 17x is a L3, the pressure receiving area a z3 of the driving portion 17y, and the driving portion 17d.
Assuming that the pressure receiving area is a s3, P L3 · a L3 + F c3 · a s3 = P z3 · a z3 (7) For convenience, if a L3 = a z3 = a s3, the bucket directional control valve 16 The differential pressure P z3 -P L3 becomes P z3 -P L3 = F c3 (8). If the gradient of the characteristic line 38 in FIG. 7 is a proportional constant γ, P z3 −P L3 = γ · ΔP LS (9)

Here, generally, assuming that the flow rate passing through the directional control valve is Q, the opening area thereof is A, the differential pressure across the direction is ΔP, and the proportionality constant is K, There is a relationship.

Therefore, the flow rates passing through the arm directional control valve 14, the boom directional control valve 12, and the bucket directional control valve 16 are Q1, Q2, and Q3, the opening areas are A1, A2, and A3, respectively, and the proportional constants are K1 and K1, respectively. Assuming K2 and K3, for the arm directional control valve 14, Regarding the boom directional control valve 12, Regarding the bucket directional control valve 16, Holds. From the above equations (11), (12), and (13), the ratio of the flow rates passing through the arm directional control valve 14, the boom directional control valve 12, and the bucket directional control valve 16, that is, the arm cylinder 5, the boom cylinder 4 , The split ratio, which is the ratio of the flow rates supplied to the bucket cylinders 6, Becomes Here, K1, K2, K3 and α, β, γ are constant, and A1, A2, A3 are also constant if the lever strokes of the operating levers 12a, 14a, 16a are constant. The shunt ratio Q1 / Q2 / Q3 is constant.

That is, in the combined drive of the boom 1, the arm 2, and the bucket 3, a stable flow rate can be supplied to each of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 without being affected by the load fluctuation of another actuator. A good composite drive can be realized at a speed corresponding to the lever stroke of the operating levers 14a, 12a, 16a. Note that the relationship between the operating speed of the arm cylinder 5 and the lever stroke of the operation lever 14a during the normal operation is, for example, a characteristic line 50 shown by a broken line in FIG.
become that way. In FIG. 10, Lm is an arm directional control valve 14 at which the operating speed of the arm cylinder 5 is maximized.
, Ie, the lever stroke corresponding to the maximum opening area.

Returning to FIG. 8, assuming that the selection device 24 has selected the specific work including the arm cloud operation, that is, the horizontal pulling work, the determination in step S2 in FIG. 8 is satisfied, so the flow proceeds to step S5. In this step S5, the arithmetic unit 28 of the controller 30 determines whether or not the detection signal Y of the arm cloud is input. Now, a pilot pressure of a level according to the operation amount of the operation lever 14a is temporarily supplied to the drive unit 14y of the arm direction control valve 14, and the detection signal Y from the arm cloud sensor 21 is supplied.
Is output, the determination at step S5 is satisfied, and the routine goes to step S6.

In this step S6, the first functional relationship stored in the storage unit 27, that is, the characteristic line 39 at the time of arm cloud operation of the horizontal pulling operation corresponding to the shunt compensation valve 15 related to the arm cylinder 5 in FIG. 6, the characteristic line 40 of the horizontal pulling operation corresponding to the branch flow compensating valve 13 related to the boom cylinder 4 in FIG. 6 during the arm cloud operation, and the horizontal pulling operation corresponding to the branch flow compensating valve 17 related to the bucket cylinder 6 in FIG. The characteristic line 41 at the time of the arm cloud operation is read out to the calculation unit 28, and the control forces F1, F2, F3 corresponding to the load sensing differential pressure ΔP LS are obtained. The control forces F1, F2, and F3 at this time are, as is apparent from FIGS.
The value is smaller than 1, F2, F3.

Next, proceeding to step S4, from the output unit 29, the electromagnetic proportional valves 33, 32,
Control force signals corresponding to the control forces F1, F2, F3 are output to each of the 34 drive units. In response, the proportional solenoid valves 33, 3
2, 34 are opened appropriately, and the pilot pressure discharged from the pilot pump 35 changes its magnitude in accordance with the degree of opening of these electromagnetic proportional valves 33, 32, 34 to control pressures Fc1, Fc2, Fc3. To the drive parts 15d, 13d, 17d of the shunt compensating valves 15, 13, 17 and these shunt compensating valves 15, 13, 17 are opened in the valve opening direction with a smaller control force F1, F2, F3 than during normal operation. Driven. Accordingly, the target value of the differential pressure between the front and rear of the arm directional control valve 14, the boom directional control valve 12, and the bucket directional control valve 16 set by the branch flow compensating valves 15, 13, 17 is controlled by the control forces F1, F2, F3. , And each of the flow rates passing through the directional control valves 14, 12, 16 becomes smaller than that in the normal operation. In other words, in the above equations (11), (12), and (13), the proportional constants α, β, and γ are represented by the characteristic lines 3 in FIGS.
The flow rates Q1, Q2, and Q3 passing through the directional control valves 14, 12, 16 also become smaller than those in the normal operation. From equation (14), a constant shunt ratio Q1 corresponding to the proportional constants α, β, γ corresponding to the slopes of the characteristic lines 39, 40, 41
/ Q2 / Q3 is obtained.

Here, the gradients (proportional constants) of the characteristic lines 39, 40, 41 shown in FIGS. 5 to 7 are determined by the arm directional control valve 14, the boom directional control valve 12, and the bucket during the arm cloud operation of the horizontal pulling operation. Of the required flow rate of the directional control valve 16
Is set to be smaller than the maximum discharge flow rate.
By setting the gradients of the characteristic lines 39, 40, and 41 in this manner, the operating speeds of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 are slower than those in the normal operation, but the operation lever 14a for the arm is operated. Even if the boom cylinder 4 and / or the bucket cylinder 6 is driven together with the arm cloud after the arm cloud is operated by operating the full stroke, even if the boom cylinder 4 and / or the bucket cylinder 6 is combinedly driven, the operating speed of the arm cylinder 5 is reduced. There is no change, and stable horizontal pulling work can be performed. Note that the operation speed of the arm cylinder 5 and the operation lever
The relationship between a and the lever stroke is as shown by the characteristic line 51 in FIG.

If the determination in step S5 in FIG. 8 is not satisfied, this is the time of the arm dumping operation of the horizontal pulling operation, and the process proceeds to step S7.

In this step S7, the third functional relationship stored in the storage unit 27, that is, the characteristic line 42 at the time of the arm dumping operation of the horizontal pulling operation corresponding to the shunt compensation valve 15 related to the arm cylinder of FIG. Dividing flow compensating valve according to boom cylinder 4 in FIG.
13 and the characteristic line 43 at the time of the arm dump operation of the horizontal pulling operation, and the shunt compensation valve related to the bucket cylinder 6 in FIG.
The characteristic line 44 at the time of the arm dump operation of the horizontal pulling operation corresponding to 17 is read out to the arithmetic unit, and the load sensing differential pressure Δ
Control forces F1, F2, F3 corresponding to PLS are determined. At this time, the control forces F1, F2, and F3 have larger values than F1, F2, and F3 on the characteristic lines 36, 37, and 38 during the normal operation, as is clear from FIGS.

Next, proceeding to step S4, from the output unit 29, the electromagnetic proportional valves 33, 32,
A control force signal corresponding to the control force F1, F2, F3 is output to each of the drive units 34, and correspondingly, the electromagnetic proportional valves 33, 3
From 2,34, the control pressure F c1, F of magnitude corresponding to the control force signal
c2, Fc3 are output, and the drive units 15d,
13d and 17d have a greater control force F in the valve opening direction than during normal operation.
1, F2 and F3 occur. As a result, the shunt compensation valves 15, 13, 17
The target value of the differential pressure across the directional control valve 14, the boom directional control valve 12, and the bucket directional control valve 16 set by the control becomes larger as the control forces F1, F2, and F3 increase. Each of the flow rates passing through the valves 14, 12, and 16 has a smaller opening area than that in the normal operation when the opening area is the same.

By the way, the operation of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 during the arm dumping operation of the horizontal pulling operation is a contraction operation in which pressurized oil is supplied to the rod side cylinder chamber, and the effective pressure receiving area of the rod side cylinder chamber is It is about half of the effective pressure receiving area of the bottom cylinder chamber. For this reason, directional control valves for arms, booms and buckets
The characteristics of the opening area with respect to the lever strokes of 14, 12, and 16 are set so that the maximum opening is about half that of the opening characteristics when these cylinders 5, 4, and 6 are driven in the extension direction. . In the arm dump operation, most of the operation is solely driven by the arm cylinder 6, and the ratio of the combined driving of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 is extremely small.

Therefore, the target value of the differential pressure across the flow control valves 14, 12, 16 set by the diverting compensation valves 15, 13, 17 is the control force F1, F2,
Even if it increases in accordance with the increase in F3, the flow rate passing through the directional control valves 14, 12, 16 is actually smaller than that during normal operation. However, the operating speeds of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 are higher than in the normal operation.

In other words, in the above equations (11), (12), and (13), the proportional constants α, β, and γ are the characteristic lines 42, 4 in FIGS.
3,43, and the opening areas A1, A2, A3 decrease when the lever stroke is the same, and as a result, the flow rates Q1, Q2, Q3 passing through the directional control valves 14, 12, 16 Each is smaller than during normal work. Further, from equation (14), constant shunt ratios Q1 / Q2 / Q3 corresponding to the proportional constants α, β, γ corresponding to the slopes of the characteristic lines 42, 43, 44 can be obtained.

Thus, the actuator including the arm cylinder 5 operates at a relatively high speed, and performs an arm dump operation.
Note that the relationship between the operating speed of the arm cylinder 5 and the lever stroke of the operation lever 14a during the arm dumping operation in the horizontal pulling operation is as shown by a characteristic line 52 in FIG.

Effect In the embodiment configured as described above, the first functional relationship indicated by the characteristic lines 39, 40, and 41 in FIGS. 5, 6, and 7 is set in the storage unit 27 of the controller 30 as described above. At this time, by considering in advance the flow rates supplied to the actuators other than the arm cylinder 5, that is, the boom cylinder 4 and the bucket cylinder 6 along with the arm cloud operation of the horizontal pulling operation, the arm of the horizontal pulling operation The combined driving of the arm cylinder 5, the boom cylinder 4, and the bucket cylinder 6 can be performed without causing a change in the operation speed of the arm cylinder 5 during cloud operation.

Further, at the time of the arm cloud of the horizontal pulling operation and at the time of the arm dump of the horizontal pulling operation, the direction control valve for the arm is changed by changing the differential pressure P z1-P L1 of the arm directional control valve 14 by the control F1 of the shunt compensation valve 15. The magnitude of the flow rate Q1 passing through 14 can be changed, as shown in FIG.
In each of the normal operation, the arm pulling operation of the horizontal pulling operation, and the arm dumping operation of the horizontal pulling operation, the lever strokes at which the operating speed of the arm cylinder 5 is maximized, that is, the arm directional control valve 14 Lm can be made equal to Lm until the maximum opening area is obtained. Therefore, the operation area of the lever that can change the flow rate during the horizontal operation of the arm cloud can be made sufficiently large to have the same operation area as that of the normal operation, and the fine operation during this arm cloud operation can be performed. , And excellent operability can be obtained without giving an uncomfortable feeling to the operator when the arm cylinder 5 is combined with another actuator. As a result, the accuracy of the horizontal pulling operation can be relatively easily secured, the number of careful operations required for improving the accuracy is reduced, and the efficiency of the horizontal pulling operation can be improved.

Furthermore, the operating speed of the arm cylinder 5 is increased during the arm dumping operation of the horizontal pulling operation, so that the arm cylinder 5 can be brought into a standby state for the next arm cloud operation in a short time, thereby improving the working efficiency. Can be done.

Another Embodiment Another embodiment of the present invention will be described with reference to FIGS. 11 to 14. In the figure, the same reference numerals are given to members equivalent to the members shown in FIG. In the present embodiment, the configurations of the branch flow compensating valve and the pump regulator are changed.

In FIG. 11, the flow compensating valves 13A, 15A, and 17A are provided with a differential pressure Pz2-P L between the flow control valves 12, 14, and 16 similarly to the embodiment of FIG.
2, the drive units 13x, 15x, 17x and the drive units 13y, 15y, 1 as means for feeding back P z1-P L1 and P z3-P L3
Has 7y. Further, the branch flow compensating valves 13A, 15A, and 17A are provided with differential pressures P z2-P L2, P z1-P L1 and P z1 of the flow control valves 12, 14, and 16, respectively.
As means for setting the target value of z3-P L3, springs 13e, 15e, 17 for urging the shunt compensating valve with a constant force F in the valve opening direction are used.
e, and control pressures F c2, F described below via lines 13c, 15c, 17c.
Drive units 13f, 15f, and 17f are provided for guiding c1 and Fc3 and biasing the branch flow compensating valve in the valve closing direction. By applying the control pressures Fc2, Fc1, and Fc3 to the driving units 13f, 15f, and 17f, the corresponding driving forces F2, F1, and F3 are generated in these driving units, and the shunt compensation valves 15A, 13A, and 17A are generated. Is urged in the valve-opening direction by the control force of F-F1, F-F2, F-F3.As a result, the differential pressure across the flow control valves 12, 14, 16 is controlled by the control force F-F1, F-F2, It is kept at the value determined by F-F3.

The storage unit 27A of the controller 30A stores a functional relationship shown in FIGS. 12 to 14 instead of the functional relationship between the control forces F1, F2, F3 and the load sensing differential pressure ΔP LS shown in FIGS. Is stored.

In FIGS. 12, 13, and 14, characteristic lines 39A, 40A, and 41A indicated by solid lines indicate specific operations including the arm cloud operation, that is, the first line set in relation to the arm cloud operation of the horizontal pulling operation. And a characteristic line 36 indicated by a broken line.
A, 37A, and 38A are the second functional relationships set in relation to the normal work, and the characteristic lines 42A, 43A, and 44A indicated by dashed lines are the third functional relations set in relation to the arm dump operation of the horizontal pulling work. It is a functional relationship.

In this embodiment, the control force F generated by the driving units 15f, 13f, 17f
Since 1, F2, and F3 act in the valve closing direction opposite to the drive units 15d, 13d, and 17d of the first embodiment, the load sensing differential pressure ΔP
The functional relationship is such that the control forces F1, F2, F3 increase as the LS decreases. Also, when the arm dumping operation of the horizontal pulling operation is performed, the target value of the pressure difference between the front and rear of the directional control valve 14 for the arm, the directional control valve 12 for the boom, and the directional control valve 16 for the bucket becomes maximum, and each actuator is moved to the maximum speed. The slopes of the characteristic lines 42A, 43A, and 44A indicating the third functional relationship are set small so that the flow rate driven by the directional control valves can be supplied. The characteristic line 36A representing the second functional relationship is such that the pressure target value is slightly less than its maximum target value, and a flow rate for driving each actuator at a speed slightly less than its maximum speed can be supplied. , 37A and 38A are slightly larger than the slopes of the characteristic lines 42, 43 and 44 showing the third functional relationship, but are set relatively small. The target value of the differential pressure before and after The first functional relationship is shown so that a moderately large flow rate can be supplied to at least the arm cylinder 5 in a range that does not cause a speed change by another actuator in the combined driving with the boom cylinder 4 and the bucket cylinder 6. The slopes of the characteristic lines 39A, 40A, 41A are set to be larger than the slopes of the characteristic lines 36A, 37A, 38A indicating the second functional relationship.

The control force signal output from the output unit 29 of the controller 30 is provided to each drive unit of the electromagnetic proportional valves 32, 33, and.

On the other hand, in the present embodiment, the main pump 11A is a fixed displacement hydraulic pump, and the discharge line 11b of the main pump 11A is connected to the tank 40 via the unload valve 22A. The unload valve 22A has opposing driving parts 22x, 22y and a spring 22h for setting an unloading pressure.The driving part 22x is loaded with a pump discharge pressure Ps via a pipe 22b, and the driving part 22y is Detection line 1
The maximum load pressure Pamax is led via 9a.

Also in the present embodiment configured as described above, the pump discharge pressure is controlled by the function of the unload valve 22A so as to be higher than the load pressure appearing in the detection line 19a by the specified value determined by the spring 22h. The load sensing system can be configured similarly to the embodiment.

Further, the springs 15e, 13c when the control pressures Fc1, Fc2, Fc3 are applied to the driving portions 15f, 13f, 17f of the branch flow compensating valves 15A, 13A, 17A.
The control forces in the valve opening direction that the e, 17e and the drive units 15f, 13f, 17f exert on the diverting compensation valve are F-F1, F-F2, F-F3, and F is constant;
Since F1, F2, and F3 are set as shown in FIGS. 12 to 14, the valve opening direction is smaller in the horizontal pulling work arm cloud operation than in the normal work, similarly to the first embodiment. Control forces F-F1, F-F2, F-F3 are set, and during the arm dump operation, the control forces F-F1, F-F2, F-F3 in the valve opening direction are set slightly larger than those during normal operation, Therefore, the same effects as in the embodiment of FIG. 1 can be obtained during the horizontal pulling operation.

In the above embodiment, the sensor 21 that detects the pilot pressure is used to detect the arm cloud operation.However, the sensor that detects the movement of the operation lever 14a or the movement of the direction control valve detects the arm cloud operation. You may.

Also, the target value of the differential pressure across the directional control valves 12, 14, 16 for the arm, boom, and bucket set by the shunt compensating valve during the horizontal dumping operation is maximized. Although a small front-back differential pressure is set in the present invention, the present invention is not limited to this, so that the same maximum front-back differential pressure is set during both normal work and horizontal pulling arm dump. Is also good.

Further, although the above description includes the three combined operations of the boom, the arm, and the bucket, the horizontal pulling operation can be performed by the two combined operations of the boom and the arm in the same manner as in the above embodiment. .

INDUSTRIAL APPLICABILITY According to the present invention, in a combined operation for performing a specific operation requiring an arm cloud operation, a combined drive can be performed without causing a change in the operating speed of an arm cylinder, and a directional control valve for an arm The operation area of the lever that can change the flow rate of the arm can be made sufficiently large, and the fine operation of the arm cloud operation becomes easy. Therefore, the operability is improved as compared with the related art, and the specific work can be performed with high accuracy without requiring special cautious operation, which has an effect of improving the efficiency of the specific work.

Continuation of the front page (72) Inventor Yusuke Kajita 4929-9 Tsurumuma, Kunitachi-cho, Tsuchiura-city, Ibaraki Pref. Kawaharaba Apartment 101 (56) References JP-A-58-11235 (JP, A) JP-A-60-11706 (JP, A) International Publication 90/683 (WO, A1) International Publication 90/2268 (WO, A1) European Publication 326150 (EP, A1)

Claims (9)

(57) [Claims] 1. A hydraulic pump (11, 11A), a plurality of actuators (4-6) including an arm cylinder (5) and a boom cylinder (4) driven by pressure oil supplied from the hydraulic pump, A plurality of flow control valves (12, 14, 16) including an arm directional control valve (14) and a boom directional control valve (12) for controlling the flow of hydraulic oil supplied to these actuators, respectively; A plurality of flow compensating valves (13, 15, 17;
A, 15A, 17A), and each of the branch flow compensating valves has a driving means (13d, 15d, 17d; 13e, 13f, 15e, 15f, 17e, 17f), wherein a first means (21) for detecting an arm cloud operation by driving the arm cylinder (5); and , At least a corresponding flow dividing compensation valve (15; 1) for decreasing the target value of the differential pressure across the flow control valve (14) related to the arm cylinder.
5A) the second means (24, 24) for controlling the driving means (15d; 15f).
30,31; 24,30A, 31) and a hydraulic drive device for civil engineering and construction machinery. 2. A hydraulic drive system for a civil engineering and construction machine according to claim 1, wherein said second means (24, 30, 31; 24,
30A, 31) are provided with a flow control valve (1) related to the arm cylinder (5) when the arm cloud operation is detected.
Each of the diversion compensating valves (15, 13; 15A, 15A, 15A, 15B) reduces both the target value of the differential pressure before and after 4) and the target value of the differential pressure of the flow control valve (12) related to the boom cylinder (4). 13A)
A hydraulic drive device for civil engineering and construction machinery, characterized by controlling the drive means (15d, 13d; 15f, 13f). 3. The hydraulic drive system for a civil engineering and construction machine according to claim 1, wherein said second means (24, 30, 31; 24,
30A, 31) includes means (24) that is operated in accordance with which of a normal operation and a specific operation including an arm cloud operation is performed, and outputs a corresponding selection signal, wherein the selection signal is output when the arm cloud operation is performed. And c) controlling the driving means (15d, 13d; 15f, 13f) of the shunt compensation valve (15, 13; 15A; 13A) when the signal is a signal corresponding to a specific operation including・ Hydraulic drive for construction machinery. 4. The hydraulic drive system for civil engineering and construction machinery according to claim 1, wherein said second means includes a discharge pressure of said hydraulic pump (11; 11A) and said plurality of actuators (4-6). ) Means for detecting the pressure difference from the maximum load pressure (1)
8,19,19a), and a first functional relationship between the differential pressure and a first control force which are set in advance corresponding to a specific operation including an arm cloud operation, and which is set in advance in correspondence with a normal operation. Means (27, 30: 27A, 30A) for storing a second functional relationship between the differential pressure and a second control force, wherein when the arm cloud operation is not detected, the detected differential pressure And the second
The second control force according to the differential pressure is obtained from the functional relationship of the above formulas, and the driving means (15d, 13d) of the shunt compensating valve (15, 13; 15f, 13f), and when the arm cloud operation is detected, the first control force corresponding to the differential pressure is obtained from the detected differential pressure and the first functional relationship. Drive means (15, 13A; 15A, 13A) for the diversion compensating valves (15, 13;
d, 13d; 15f, 13f). 5. A hydraulic drive system for a civil engineering and construction machine according to claim 1, wherein said second means comprises a drive means (15d, 13d) for said diversion compensation valve (15, 13; 15A, 13A). ; 15f, 13f)
(30; 30A) for calculating a control force to be generated by the controller and outputting a corresponding control force signal, and a control pressure generating means for generating a control pressure corresponding to the calculated control force based on the control force signal (31) A hydraulic drive device for a civil engineering / construction machine, comprising: 6. A hydraulic drive system for a civil engineering and construction machine according to claim 5, wherein said control force generating means includes a pilot hydraulic source (35) and an electromagnetic source for generating said control pressure based on said hydraulic source. A hydraulic drive system for civil engineering and construction machinery, comprising: a proportional valve (32, 33, 34). 7. A hydraulic drive system for civil engineering and construction machinery according to claim 1, wherein the flow control valve (14) related to said arm cylinder (5) is a pilot-operated valve driven by pilot pressure. And a first means for detecting the pilot pressure for driving the arm cylinder in the extension direction (21). 8. A hydraulic drive system for a civil engineering / construction machine according to claim 1, wherein said drive means for said diverting compensation valve (13, 15, 17) generates a control force to control said diverting compensation valve. The second means (30, 31) includes a single drive unit (13d, 15d, 17d) that drives in the valve opening direction, and the second unit (30, 31) performs control generated by the drive unit when the arm cloud operation is detected. Hydraulic drive for civil engineering and construction machinery, characterized in that the force is smaller than usual. 9. The hydraulic drive system for civil engineering and construction equipment according to claim 1, wherein said branching compensation valve (13A, 15A, 17
The driving means (A) includes a spring (13e, 15e, 17e) for driving the flow dividing compensating valve in the valve opening direction, and a driving unit (13f, 13f, 13g for generating a control force and driving the flow dividing compensating valve in the valve closing direction. 15f, 17f), wherein the second means (30A, 31) increases the control force generated by the drive unit when the arm cloud operation is detected, as compared with normal. Hydraulic drive for construction machinery.