JP2001182103A - Control device for construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply add a control valve without the constraint of an installation space, when a hydraulic actuator is mounted additionally. SOLUTION: This control device for the construction machinery has a first hydraulic actuator operated by first control valves 57-60, 62-65 interposed to the first hydraulic-fluid feed passage, a bypass returning a hydraulic fluid which is not fed to the first hydraulic actuator to a tank, the second hydraulic actuator operated by the second control valves interposed to the second hydraulic-fluid feed passage installed part from the first hydraulic-fluid feed passage, and control means 3 (4) controlling a pump flow rate by selecting either one of the first control signal set, on the basis of characteristics being approximately in inverse proportion to the flow rate of the hydraulic fluid in the bypass and the second control signal set, on the basis of characteristics being approximately in direct proportion to an operating-member manipulated variable, and the second control signal is selected, when the control means 3 (4) caused the second hydraulic actuator to operate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a construction machine for controlling a discharge flow rate of hydraulic oil from a hydraulic pump for operating a work machine of a construction machine such as a hydraulic shovel.

[0002]

2. Description of the Related Art Generally, construction machines such as hydraulic excavators are
As shown in FIG. 9, the upper revolving unit 102 and the lower traveling unit 10
0 and a work machine 118. Undercarriage 100
Has a right track 100R and a left track 100L that can be driven independently of each other. On the other hand, the upper revolving unit 102 is provided so as to be rotatable in a horizontal plane with respect to the lower traveling unit 100. For this reason, a traveling hydraulic motor (hydraulic actuator for traveling) as an independent power source is attached to each of the left track 100L and the right track 100R of the lower traveling body 100, and
02 is provided with a turning hydraulic motor (turning hydraulic actuator).

[0003] The working machine 118 is mainly provided with the boom 10.
3, a stick 104, a bucket 108, and the like, and the boom 103 is pivotally attached to the upper swing body 102. Also, at the tip of the boom 103,
Similarly, a stick 104 is rotatably connected in the vertical plane. A boom drive hydraulic cylinder (boom cylinder, boom drive hydraulic actuator) 105 for driving the boom 103 is provided between the upper swing body 102 and the boom 103, and the boom 10
Between the stick 3 and the stick 104, a stick driving hydraulic cylinder (stick cylinder, stick driving hydraulic actuator) for driving the stick 104
106 is provided. Further, between the stick 104 and the bucket 108, a bucket driving hydraulic cylinder (bucket cylinder,
A bucket driving hydraulic actuator 107 is provided. Accordingly, the boom 103 can rotate in the directions of arrows a and b in FIG. 9, the stick 104 can rotate in the directions of arrows c and d in FIG. 9, and the bucket 108 can rotate in the directions of arrows e and f in FIG. Is configured.

The rotation of the boom 103 in the direction of arrow a in FIG. 9 is called boom up, and the rotation in the direction of arrow b in FIG. 9 is called boom down. The rotation of the stick 104 in the direction of arrow c in FIG. 9 is called stick-out, and the rotation of the stick 104 in the direction of arrow d in FIG. 9 is called stick-in. The rotation of the bucket 108 in the direction of arrow e in FIG. 9 is referred to as bucket open, and the rotation of the bucket 108 in the direction of arrow f in FIG. 9 is referred to as bucket-in.

As described later, the cylinders 105 to 107 and the hydraulic motor include a hydraulic pump driven by an engine (mainly a diesel engine), a control valve for a boom, a control valve for a stick, and a control valve for a bucket. Control valve,
A hydraulic circuit including a plurality of control valves such as a turning control valve is connected. Further, the driving operation room 1 of the upper swing body 102
01 is provided with a plurality of operating members such as a left lever, a right lever, a left pedal, and a right pedal for controlling the operation (running, turning, boom turning, stick turning, and bucket turning) of the excavator. ing. Then, the moving amounts of the plurality of control valves are controlled in accordance with the operation of the operation member by the operator, whereby the cylinders 105 to 107 and the hydraulic motor are driven.

In this manner, each of the cylinders 105 to 10
7 is driven to extend and retract, and the boom 103, the stick 104,
Various works such as excavation work are performed by driving the work implement 118 such as the bucket 108 or driving the turning motor to turn the upper turning body 102.
Here, FIG. 10 is a diagram schematically showing a main part of a hydraulic circuit provided in a conventional hydraulic shovel.

[0007] As shown in FIG.
5 to 107 and the hydraulic motors 109L, 109R, and 110 include a plurality (two in this case) of hydraulic pumps 510 driven by an engine (mainly, a diesel engine) 500.
520, a plurality of control valves (supply / discharge control valves) 570-600,
A hydraulic circuit 530 including 620 to 650 is connected.

Then, the operator operates the plurality of operating members 54.
When 0 is operated, the movement amounts of the control valves 570 to 600 and 620 to 650 interposed in the hydraulic circuit 530 are controlled,
As a result, the hydraulic oil from each of the hydraulic pumps 510 and 520 is supplied at a predetermined pressure via the hydraulic circuit 530, and each of the hydraulic cylinders 105 to 10 is supplied according to the supplied hydraulic pressure.
7 and the hydraulic motors 109L, 109R, 110 are driven.

The plurality of operating members 540 are connected to the boom 1
03 is operated when rotating the stick 104, the stick operating member 540b is operated when rotating the stick 104, and the bucket is operated when rotating the bucket 108. 540c, a turning operation member 540d for operating when the upper swing body 102 is turned, and a traveling operation member 540e for operating when the upper turning body 102 is driven.

Here, the hydraulic pumps 510 and 520 discharge the hydraulic oil in the reservoir tank 700 as a predetermined oil pressure. Here, a swash plate rotary piston pump (piston type variable displacement pump, variable discharge amount type piston) is used. pump)
It is configured as These hydraulic pumps 510, 5
20 is a piston (not shown) provided in the hydraulic pump
By changing the stroke amount, the pump discharge flow rate can be adjusted. That is, in these hydraulic pumps 510 and 520, one end of the piston is configured to abut against a swash plate (creep plate: not shown), and the hydraulic oil discharged from the hydraulic pumps 510 and 520 and each control valve The hydraulic fluid on the downstream side of 570 to 600 and 620 to 650 is guided to change the inclination (tilt angle) of the swash plate of the hydraulic pumps 510 and 520, thereby changing the stroke amount of the piston and adjusting the pump discharge flow rate. It is possible to do it.

[0011] The hydraulic circuit 530, as shown in FIG.
The first circuit unit 550 and the second circuit unit 560 are provided. The first circuit unit 550 includes an oil passage 610 connected to the first hydraulic pump 510 and a control valve 5 for a right traveling motor interposed in the oil passage 610 and controlling supply and discharge of hydraulic oil.
70, bucket control valve 580, first boom control valve 5
90, and a supply / discharge control valve such as a second stick control valve 600.

The hydraulic oil from the first hydraulic pump 510 is supplied to the right traveling motor 109R via the oil passage 610 and the right traveling motor control valve 570, and is supplied to the right traveling motor 10R.
9R is driven. The hydraulic oil from the first hydraulic pump 510 is supplied to the bucket driving hydraulic cylinder 107 via the oil passage 610 and the bucket control valve 580, and also via the oil passage 610 and the first boom control valve 590. To the hydraulic cylinder 105 for boom drive, and further to the oil passage 610 and the control valve 60 for the second stick.
0 to the hydraulic cylinders 106 for driving the sticks.
Is driven.

A throttle 810 is provided downstream of the oil passage 610b of the first circuit portion 550, and a control valve 570 is provided.
The bypass flow rate at the position of 600 to the neutral or intermediate movement position is such that the hydraulic oil from the first hydraulic pump 510 is returned to the reservoir tank 700 through the throttle 810. Further, the hydraulic oil on the upstream side (control valve side) of the throttle 810 is guided to the hydraulic pump 510,
The tilt angle of the hydraulic pump 510 is controlled by the pressure of the hydraulic oil.

The second circuit section 560 includes the second hydraulic pump 52
0, and a left traveling motor control valve 620 interposed in the oil passage 660 for controlling the supply and discharge of hydraulic oil.
Swing motor control valve 630, first stick control valve 6
40, and a supply / discharge control valve such as a second boom control valve 650. Then, the hydraulic oil from the second hydraulic pump 520 is supplied to the left traveling motor 109L via the oil passage 660 and the left traveling motor control valve 620, whereby
The left traveling motor 109L is driven.
The hydraulic oil from the second hydraulic pump 520 is supplied to the oil passage 66
0, the swing motor 11 via the swing motor control valve 630
0, whereby the turning motor 110 is driven. Further, the second hydraulic pump 520
Is supplied to the stick driving hydraulic cylinder 106 via the oil passage 660 and the first stick control valve 640, and the boom driving hydraulic pressure is supplied via the oil passage 660 and the second boom control valve 650. The cylinder 105 is supplied to the cylinder 105, whereby the cylinders 105 and 106 are driven.

A throttle 820 is provided downstream of the oil passage 660c of the second circuit section 560, and the control valves 620 to 620 are provided.
The bypass flow rate at the neutral or intermediate moving position 650 returns the hydraulic oil from the second hydraulic pump 520 to the reservoir tank 700 through the throttle 820.
Further, the hydraulic oil on the upstream side (control valve side) of the throttle 820 is guided to the hydraulic pump 520, and the tilt angle of the hydraulic pump 520 is controlled by the pressure of the hydraulic oil. I have.

Further, the second circuit section 5 is provided so that a sufficient hydraulic oil can be supplied to the stick 104 which is important for the operation of the construction machine even when the stick 104 is simultaneously operated with another work machine 118.
60 in addition to the hydraulic oil from the second hydraulic pump 520,
The hydraulic oil from the first hydraulic pump 510 of the circuit section 550 is also supplied to the hydraulic cylinder 106 for driving the stick.

Therefore, the oil passage 660 of the second circuit portion 560
The first stick control valve 640 is interposed in the oil passage 610 of the first circuit unit 550.
Is interposed. Then, the first stick control valve 6
The amount of movement of the second stick control member 6 is controlled in accordance with the amount of movement of the stick operating member 540b.
By controlling the movement amount of 00 in accordance with the operation amount of the stick operation member 540b, supply and discharge of hydraulic oil to and from the stick drive hydraulic cylinder 106 can be performed.

Similarly, in addition to the hydraulic oil from the first hydraulic pump 510 of the first circuit section 550, a sufficient hydraulic oil is supplied to the boom 103 even when operating simultaneously with another working machine 118. Second hydraulic pump 52 of second circuit section 560
Hydraulic oil from 0 is also supplied to the boom drive hydraulic cylinder 105. Therefore, the first circuit unit 55
The first boom control valve 590 is interposed in the zero oil passage 610, and the second boom control valve 650 is interposed in the oil passage 660 of the second circuit portion 560. The amount of movement of the first boom control valve 590 is controlled according to the amount of operation of the boom operating member 540a, and the second boom control valve 650 is controlled.
Is controlled in accordance with the amount of operation of the boom operating member 540a, whereby the boom driving hydraulic cylinder 105 is controlled.
Supply and discharge of hydraulic oil to and from the engine.

A pilot hydraulic circuit having a pilot pump (not shown) and a proportional pressure reducing valve (not shown) is also provided to control the amount of movement of each of the control valves 570 to 600 and 620 to 650 according to the amount of operation of each operation member 540. Each of the control valves 570 to 600, 620 to 650 has a pilot pressure from a pilot pump set to a predetermined pressure by a proportional pressure reducing valve.
To act on.

Incidentally, each of the control valves 570 to 600, 62
Reference numerals 0 to 650 are configured as spool valves, and each is provided with a plurality (here, five) of throttles. For example, as shown in FIG. 11, the swing motor control valve 630 includes oil passages (hydraulic oil supply passages, PC passages) 660 and 66 that communicate the second hydraulic pump 520 and the swing motor 110.
0a and 970, and a C-T interposed in oil passages (operating oil discharge passages, CT passages) 960 and 660b that connect the turning motor 110 and the reservoir tank 700. Restrictor 41, bypass passage restrictor 4 interposed in bypass oil passages (bypass passages) 660 and 660 c communicating between second hydraulic pump 520 and reservoir tank 700.
2 is provided. The hydraulic oil supply passage and the hydraulic oil discharge passage constitute a hydraulic oil supply / discharge passage.

The oil passage 6 which connects the second hydraulic pump 520 and the swing motor 110 by the PC throttle 40 is provided.
The opening area of 60, 660a, 970 [opening area of hydraulic oil supply passage, PC opening area (PC)] is adjusted. In addition, the CT throttle 41 adjusts the opening area of the oil passages 960 and 660b (the opening area of the hydraulic oil discharge passage, the CT opening area (CT)) that connects the turning motor 110 and the reservoir tank 700. . Further, the bypass passage restrictor 4
2, the second hydraulic pump 520 and the reservoir tank 7
The opening areas of the oil passages 660 and 660c that communicate with 00 (the opening area of the bypass passage, the area of the bypass opening (C)) are adjusted.

In FIG. 11, the swing motor control valve 6 is shown.
Although 30 is in the left turning side position, the turning motor control valve 630 is moved upward in FIG. 11 according to the operation amount of the turning motor operation member 540d (the operation member operation amount (A)). By turning the bypass passage restrictor 42 of the swing motor control valve 630 into the bypass passages 660 and 660c, the amount of movement of the swing motor control valve 630 (the control valve movement amount (B)) is adjusted. The motor control valve 630 can be in the neutral position. Further, the swing motor control valve 630 is connected to the swing motor operation member 540d.
FIG. 11 according to the operation amount [operation member operation amount (A)] of FIG.
The control valve 630 for the swing motor is moved to the uppermost position in
Of the P-C restrictor 40 through the P-C passages 660, 660a, 97
0, and the CT throttle 41 of the swing motor control valve 630 is interposed in the CT passages 960 and 660b, thereby moving the swing motor control valve 630 [control valve travel amount (B). ], The turning motor control valve 630 can be set to the right turning side position. When the turning motor control valve 630 is located between the left turning side position and the neutral position or between the neutral position and the right turning side position, it is said to be at the intermediate moving position.

Although the hydraulic circuit for driving the swing motor 110 has been described as an example here, another hydraulic actuator 105 such as a stick driving hydraulic cylinder is used.
To 107, 109R, and 109L are similarly configured. A hydraulic circuit for driving the hydraulic actuators 105 to 107, 109R, 109L, 110 is configured as described above. For example, to operate the turning motor 110 included in these hydraulic actuators, Pump flow control (pump tilt angle control) is performed.

The operating member 5 for the swing motor by the operator
When the operation amount 40A is operated and the operation amount (A) is A0, based on a characteristic indicating the relationship between the operation member operation amount (A) and the control valve movement amount (B) as shown in FIG. Thus, the movement amount (B) of the swing motor control valve 630 as the supply / discharge control valve is set to B0. Next, according to the movement amount B0 of the swing motor control valve 630, the characteristic showing the relationship between the control valve movement amount (B) and the bypass passage opening area (C) as shown in FIG. Based on the swing motor control valve 6
30 has a bypass passage opening area (C) of C0. In this case, the CT opening area (CT) of the swing motor control valve 630 becomes CT0, and the PC opening area (PC)
Becomes PC0.

When the load pressure is constant, FIG.
Based on the characteristic indicating the relationship between the bypass passage opening area (C) and the bypass flow rate (D) as shown in FIG. 2C, the swing motor control is performed according to the bypass passage opening area C0 of the swing motor control valve 630. The flow rate (D) of the hydraulic oil flowing through the bypass passage of the valve 630 (by-pass flow rate) becomes D0. Thereby, the bypass flow rate D is determined based on the characteristic indicating the relationship between the bypass flow rate (D) and the pressure (E) of the hydraulic oil guided to the hydraulic pump 520 as shown in FIG.
0, the pressure (E) of the hydraulic oil guided to the hydraulic pump 520 becomes E0, and the pressure (E) of the hydraulic oil guided to the hydraulic pump 520 and the pump flow rate (pump tilt) as shown in FIG. Angle) (F), the pump tilt angle (pump flow rate) of the hydraulic pump 520 according to the pressure E0 of the hydraulic oil guided to the hydraulic pump 520 based on the characteristic indicating the relationship with the hydraulic pump 520.
(F) is set to F0.

Here, the case where only the swing motor 110 is operated is described. However, when the other hydraulic actuators 105 to 107, 109R, and 109L are simultaneously operated, the pump tilts of the hydraulic pumps 510 and 520 are performed. In order to control the turning angle, the hydraulic oil in the bypass passage (upstream of the throttles 810 and 820) on the downstream side of each supply / discharge control valve is introduced. ~ 107,109R,
The smallest opening area of the bypass passage opening areas of the respective supply / discharge control valves for controlling the supply / discharge of hydraulic oil to / from 109L and 110 is used.

By the way, in the hydraulic circuit 530 configured as described above, as shown in FIG.
Control valves 570 to 600, 6 that operate according to the operation amount of
20 to 650 are oil passages 610 constituting a bypass passage,
610b, 660, 660c are arranged in series, and the control valves 600, 650 and the tank 70 arranged at the most downstream
Oil passages 610b, 66 forming a bypass passage between
0c (the oil passage on the upstream side of the throttles 810, 820) and the hydraulic pumps 510, 520 are connected. Then, the pump tilt angles (pump flow rates) of the hydraulic pumps 510, 520 are controlled based on the pressure of the hydraulic oil guided from the oil passages 610b, 660c constituting the bypass passage (such as this). Control is called negative flow control).

For example, a plurality of operating members 540 are simultaneously operated, and the respective hydraulic actuators 105 to 107, 109
When simultaneously operating the R, 109L, and 110, the hydraulic oil flowing through the bypass passages 660 and 660c downstream of the supply / discharge control valves is guided to the hydraulic pumps 510 and 520.
The hydraulic pump 510 is controlled so that the pump discharge flow rate of the hydraulic pumps 510, 520 becomes the sum of the required flow rates of the hydraulic actuators 105 to 107, 109R, 109L, 110 to which the hydraulic oil is supplied via the respective supply / discharge control valves. , 520 are controlled.

[0029]

By the way, in a conventional construction machine which performs negative flow control, the above-mentioned hydraulic actuators (for boom, for stick, for bucket, for turning, for traveling) 10
5-107, 109R, 109L, 110 are equipped as standard equipment hydraulic actuators. Also, the standard equipped hydraulic actuators 105 to 107, 109R, 10
In addition to the 9L and 110, an additional hydraulic actuator may be optionally provided. In this case, it is necessary to additionally provide a hydraulic circuit including a supply / discharge control valve for the additional hydraulic actuator in order to supply / discharge hydraulic oil to / from the additional hydraulic actuator.

However, in the case where the pump tilt angle (pump flow rate) is controlled by the negative flow control as described above, when such an additional hydraulic actuator is provided, the position of the supply / discharge control valve for the additional hydraulic actuator is set. There are restrictions. That is, in the case where the pump tilt angle (pump flow rate) is controlled by the negative flow control as described above, the standardly equipped hydraulic actuators 105 to 107, 109R, 109L, 110
Control valves 570 to 600 for controlling the supply and discharge of hydraulic oil to
Oil passages 610 to 620 constitute a bypass passage.
610b, 660, and 660c are arranged in series. Then, each of these control valves 570 to 600, 62
The control valve 60 disposed on the most downstream side of 0 to 650
0,650 and the oil passage between the tank 700 (that is, the oil passage upstream of the throttles 810, 820 disposed downstream of the control valves 570-600, 620-650) 610b, 66.
0c and the hydraulic pumps 510, 520 are connected,
The pump tilt angles (pump flow rates) of the hydraulic pumps 510 and 520 are controlled based on the pressure of the hydraulic oil guided from the oil passages 610b and 660c.

For this reason, the supply / discharge control valves for the additional hydraulic actuators are provided as standard equipped hydraulic actuators 105 to 10.
7, 109R, 109L, and 110 need to be arranged in series with control valves 570 to 600, 620 to 650 that control supply and discharge of hydraulic oil to and from 110. Actually, the installation position of the supply / discharge control valve for the additional hydraulic actuator is shown in FIG.
70 to 600, 620 to 650, downstream of the control valves 600, 650 arranged at the most downstream side, and the throttle 8
It is limited to oil passages 610b and 660c on the upstream side of 10,820. In this case, an oil passage 610b between the control valve 600 and the throttle 810 and the control valve 650 and the throttle 8
The oil passage 610b between the control valve 600 and the restrictor 810 and the control valve 650 and the restrictor 82
It is also necessary to design the oil passage 660c between 0 and 0 so that it can be divided.

The supply / discharge control valve for the additional hydraulic actuator is provided with oil passages 610, 610 constituting a bypass passage.
b, 660 and 660c need to be arranged in series with the control valves 570 to 600 and 620 to 650 for the standard hydraulic actuators. For example, there are a plurality of additional hydraulic actuators, When it is necessary to provide a supply / discharge control valve for an additional hydraulic actuator, it may be difficult to add the supply / discharge control valve due to restrictions on the machine space.

In this case, a supply / discharge control valve for an additional hydraulic actuator is provided as standard equipment.
It is difficult to accurately control the tilting angle of the pump by negative flow control if they are not arranged in series with 70 to 600, 620 to 650, but are dispersed so that the body space can be used effectively. The present invention has been made in view of such a problem, and when an additional hydraulic actuator is provided, the degree of freedom of the installation position of the control valve for the additional hydraulic actuator is increased (the flexibility is increased), and the additional hydraulic pressure is increased. An object of the present invention is to provide a control device for a construction machine, in which a control valve for an actuator can be easily added without being restricted by an installation space.

[0034]

According to a first aspect of the present invention, there is provided a control device for a construction machine according to the present invention, comprising: an operation member which is operated by an operator to output an electric signal; and a hydraulic pressure which discharges hydraulic oil in a tank. A pump, a first hydraulic actuator driven by supplying hydraulic oil discharged from the hydraulic pump through the first hydraulic oil supply passage, and a first hydraulic pressure interposed in the first hydraulic oil supply passage. A first control valve for controlling the supply of hydraulic oil to the actuator, a bypass passage for returning hydraulic oil not supplied to the first hydraulic actuator via the first control valve to the tank, and discharge from the hydraulic pump A second hydraulic actuator driven by supplying the hydraulic oil to be supplied through a second hydraulic oil supply passage provided separately from the first hydraulic oil supply passage;
And a second control valve interposed in the hydraulic oil supply passage for controlling the supply of hydraulic oil to the second hydraulic actuator, and a second control valve which is set based on a characteristic substantially inversely proportional to a flow rate of the hydraulic oil in the bypass passage. And controlling the discharge flow rate of the hydraulic oil from the hydraulic pump by selecting one of the first control signal and a second control signal set based on a characteristic substantially directly proportional to the operation amount of the operation member. Control means for operating the second hydraulic actuator of the operation members when the electric signal is input from the operation member, the control means selects the second control signal, and selects the second control signal from the hydraulic pump. It is characterized in that it is configured to control the discharge flow rate of the hydraulic oil.

According to a second aspect of the present invention, there is provided a control device for a construction machine according to the first aspect, further comprising a bypass passage shutoff valve for interrupting a flow of hydraulic oil returned to the tank through the bypass passage. The means controls the bypass passage cutoff valve so as to shut off the bypass passage when an electric signal is input from the operation member for operating the second hydraulic actuator among the operation members. Thus, the hydraulic oil is used to operate the first and second hydraulic actuators without returning to the tank.

In the control apparatus for a construction machine according to the present invention, the bypass flow rate detecting means for detecting the flow rate of the hydraulic oil in the bypass path is provided in the bypass path downstream of the first control valve. Is established. Further, a bypass passage shutoff valve for shutting off the flow of the hydraulic oil returned to the tank through the bypass passage is provided in the bypass passage on the upstream side of the bypass flow rate detecting means. The control means is configured to select a control signal for reducing the pump flow rate from the first control signal and the second control signal to control the discharge flow rate of the hydraulic oil from the hydraulic pump, and When an electric signal is input from an operation member for operating the second hydraulic actuator, the bypass passage shutoff valve is controlled so as to shut off the bypass passage.

Thus, when an electric signal is input from the operating member for operating the second actuator, the bypass passage is shut off, so that the hydraulic fluid in the bypass passage detected by the bypass flow rate detecting means is detected. The flow rate becomes zero (or near zero), and the pump flow rate set based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage becomes maximum (or near maximum). As a result, the pump flow rate when controlled by the second control signal set based on the characteristic that is substantially directly proportional to the operation amount of the operation member becomes smaller than the pump flow rate when controlled by the first control signal. Therefore, the second control signal is selected by the control means, and the discharge flow rate of the hydraulic oil from the hydraulic pump is controlled based on the second control signal.

In the control apparatus for a construction machine according to the present invention, the bypass flow rate detecting means for detecting the flow rate of the hydraulic oil in the bypass path is provided in the bypass path downstream of the first control valve. You. The control means is configured to select a control signal for reducing the pump flow rate from the first control signal and the second control signal to control the discharge flow rate of the hydraulic oil from the hydraulic pump, and When an electric signal is input from an operation member for operating the second hydraulic actuator, the detection value detected by the bypass flow rate detection unit is set to zero.

In this way, when an electric signal is input from the operating member for operating the second actuator, the detection value detected by the bypass flow rate detecting means is set to zero (or a predetermined value close to zero). In addition, the pump flow rate set based on the characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage becomes the maximum (or near the maximum). As a result, the pump flow rate when controlled by the second control signal set based on the characteristic substantially directly proportional to the operation amount of the operation member becomes smaller than the pump flow rate when controlled by the first control signal. Therefore, the second control signal is selected by the control means, and the discharge flow rate of the hydraulic oil from the hydraulic pump is controlled based on the second control signal.

[0040]

Embodiments of the present invention will be described below with reference to the drawings. First, a construction machine according to the present embodiment will be described. This construction machine is a construction machine (working machine) such as a hydraulic shovel, as described in the related art (see FIG. 9), and includes the upper swing body 102, the lower traveling body 100, and the working machine 118. I have.

The lower running body 100 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper revolving body 102 is
It is provided so as to be pivotable in a horizontal plane with respect to 00. The working machine 118 mainly includes the boom 103 and the stick 1.
04, bucket 108, etc.
Is pivotally attached to the upper swing body 102. A stick 104 is connected to the tip of the boom 103 so as to be rotatable in a vertical plane.

A boom drive hydraulic cylinder (boom cylinder, boom drive hydraulic actuator) 105 for driving the boom 103 is provided between the upper swing body 102 and the boom 103, and the boom 10
Between the stick 3 and the stick 104, a stick driving hydraulic cylinder (stick cylinder, stick driving hydraulic actuator) for driving the stick 104
106 is provided. Further, between the stick 104 and the bucket 108, a bucket driving hydraulic cylinder (bucket cylinder,
A bucket driving hydraulic actuator 107 is provided.

With such a configuration, the boom 1
03 is configured to be rotatable in the directions a and b in the figure, the stick 104 is rotatable in the directions c and d in the figure, and the bucket 108 is configured to be rotatable in the directions e and f in the figure. Here, FIG. 2 is a diagram schematically showing a main part of a hydraulic circuit of such a hydraulic shovel.

As shown in FIG. 2, the left track 10
0L and the right track 100R are provided with traveling motors 109L and 109R as independent power sources, respectively, and the upper revolving unit 102 is used for rotating the upper revolving unit 102 with respect to the lower traveling unit 100. A swing motor 110 is provided. These traveling motors 10
The 9L, 109R and the swing motor 110 are configured as hydraulic motors operated by hydraulic pressure, and as described later, a plurality (two in this case) of hydraulic pumps 51, driven by an engine (mainly, a diesel engine) 50 Hydraulic oil from 52 is supplied at a predetermined pressure via a hydraulic circuit 53, and each hydraulic motor 109L, 109R, 110 is driven in accordance with the hydraulic pressure supplied in this manner.

Here, the hydraulic pumps 51 and 52 discharge the hydraulic oil in the reservoir tank 70 as a predetermined hydraulic pressure. Pump). These hydraulic pumps 51 and 52 can adjust the pump discharge flow rate by changing the stroke amount of a piston (not shown) provided in the hydraulic pump.

That is, in these hydraulic pumps 51 and 52, one end of the piston is configured to abut a swash plate (creep plate: not shown), and the inclination (tilt angle) of the swash plate will be described later. By changing the stroke amount of the piston based on the operation signal from the controller 1 to adjust the pump discharge flow rate.

As described above, the inclination of the swash plate can be changed based on the operation signal from the controller 1.
Since the amount of operation of each operating member 54 by the operator can be taken into account in addition to the pressure of the hydraulic oil in the oil passages constituting the hydraulic circuit, the pressure of the hydraulic oil in the oil passages is derived as in the related art. As compared with the case where the inclination of the swash plate is changed, the driving feeling of the operator can be improved.

The engine 50 can be set by switching the engine speed setting dial by an operator. Here, the maximum engine speed (for example, about 2000 rpm) and the minimum engine speed (for example, about 2000 rpm) are set. (For example, about 1000 rpm). It should be noted that the engine speed is not limited to such a stepwise switching.
It may be one that can be changed smoothly. The total horsepower of the engine 50 is consumed to drive these hydraulic pumps 51 and 52 and a pilot pump 83 described later.

The cylinders 105 to 107 are supplied from a plurality of (two in this case) hydraulic pumps 51 and 52 driven by the engine 50, similarly to the traveling motors 109L and 109R and the turning motor 110. It is driven by the hydraulic pressure of the operating oil. The operation room 101 includes a plurality of left levers, right levers, left pedals, right pedals, and the like for controlling the operation (running, turning, boom turning, stick turning, and bucket turning) of the excavator. An operation member 54 is provided.
These operation members 54 are configured as electric operation members (for example, electric operation levers), and output an electric signal corresponding to the operation amount to a controller (control means) 1 described later.

Further, a plurality of work mode switches are also provided in the driving cab 101, and various modes such as a boom priority mode, a swing priority mode, a leveling mode, and a tamping mode are set according to the operation by the driver. Therefore, the most suitable one can be appropriately selected. In a normal case where such a selection is not made, the operation of the stick 104 is important in the operation of the construction machine, and the operation of the stick 104 needs to be given the highest priority.

When the operator operates these operating members 54, for example, the control valves 57 to 60 and 62 to 65 interposed in the hydraulic circuit 53 are controlled, and the cylinders 105 to 107 and the hydraulic motor are controlled. 109L, 109
R, 110 is driven. Thereby, the upper rotating body 10
2 can be turned, the boom 103, the stick 104, the bucket 108, and the like can be rotated, and the hydraulic excavator can run.

The members operated when rotating the boom 103 include a boom operating member 54a and a stick 10
4 is operated when rotating the bucket 4, the bucket operating member 54 c is operated when rotating the bucket 108, and the upper revolving body 102 is operated when rotating the bucket 108.
The operation member 54 for turning is operated when turning the
d, a driving operation member 5 operated when the vehicle is driven
4e.

Next, the hydraulic circuit 53 for controlling these cylinders will be described. The hydraulic circuit 53
As shown in FIG. 2, a first circuit unit 55 and a second circuit unit 56
And The first circuit portion 55 includes an oil passage 61 connected to the first hydraulic pump 51, a control valve 57 for a right running motor, a control valve 58 for a bucket,
First boom control valve 59, second stick control valve 60
And the like.

Then, the hydraulic oil from the first hydraulic pump 51 is supplied to the right traveling motor 109R via the oil passage 61 and the right traveling motor control valve 57 to drive the right traveling motor 109R. . Also, the first hydraulic pump 51
Is supplied to the bucket driving hydraulic cylinder 107 via the oil passage 61 and the bucket control valve 58, and the boom driving hydraulic cylinder 105 via the oil passage 61 and the first boom control valve 59. Is supplied to the hydraulic cylinder 106 for driving the stick via the oil passage 61 and the control valve 60 for the second stick, whereby the cylinders 105, 106, and 107 are driven.

The oil passage 61 of the first circuit section 55 is connected to the hydraulic actuators 105 to 105 through the control valves 57 to 60, respectively.
Hydraulic oil not supplied to 107, 109R is supplied to tank 7
An oil passage 61b is provided as a bypass passage returning to zero. Then, as described later, the flow rate of the hydraulic oil flowing through the oil passage 61b is detected, and the discharge flow rate from the hydraulic pump 51 is controlled based on the detected flow rate of the hydraulic oil (negative flow control). I have. That is, the first circuit unit 55 is configured to perform negative flow control as pump flow control.

Here, a throttle 81 is provided in the oil passage 61b on the downstream side of each of the control valves 57 to 60 as a component of the bypass pressure detecting means, and each of the control valves 57 to 60 is in the neutral position or the intermediate movement position. (Position between the both-end moving position and the neutral position), the first hydraulic pump 5
1 is returned to the reservoir tank 70. The pressure in the bypass passage 61b upstream of the throttle 81 is reduced by the throttle 81.
Since the pressure changes in accordance with the flow rate of the working oil flowing through the inside, the pressure in the bypass passage 61b is detected by the pressure sensor 74 as a component of the bypass pressure detecting means, so that the operation flowing in the bypass passage 61b is performed. It detects the flow rate of oil. For this reason, the throttle 81 and the pressure sensor 74 are also referred to as bypass flow rate detecting means.

Here, the flow rate of the hydraulic oil flowing in the bypass passage 61b is detected by detecting the pressure in the bypass passage 61b by the pressure sensor 74. However, the present invention is not limited to this. For example, a bypass passage 61 is provided by a flow sensor (bypass flow rate detecting means).
Alternatively, the flow rate of the hydraulic oil flowing through the inside b may be detected.

The second circuit portion 56 includes an oil passage 66 connected to the second hydraulic pump 52, a left traveling motor control valve 62, a turning motor control valve 63, and a first stick Control valve such as the control valve 64, the second boom control valve 65, and the throttle 82. Then, the operating oil from the second hydraulic pump 52 is supplied to the left traveling motor 109L via the oil passage 66 and the left traveling motor control valve 62, whereby the left traveling motor 109L is driven. I have. The hydraulic oil from the second hydraulic pump 52 is supplied to the swing motor 110 via the oil passage 66 and the swing motor control valve 63, whereby the swing motor 11 is rotated.
0 is driven. Further, the hydraulic oil from the second hydraulic pump 52 is supplied to the stick driving hydraulic cylinder 10 via the oil passage 66 and the first stick control valve 64.
6 and is supplied to a boom drive hydraulic cylinder 105 via an oil passage 66 and a second boom control valve 65, whereby the respective cylinders 105 and 106 are driven.

The oil passage 66 of the second circuit section 56 is connected to the hydraulic actuators 105 and 105 via the control valves 62 to 65.
An oil passage 66c is provided as a bypass passage for returning the hydraulic oil not supplied to the tanks 106, 110, and 109L to the tank 70. Then, as described later, this oil passage 6
The flow rate of the hydraulic oil flowing through the hydraulic pump 6c is detected, and the discharge flow rate from the hydraulic pump 52 is controlled based on the detected flow rate of the hydraulic oil (negative flow control). That is, the second circuit unit 56 is configured to perform negative flow control.

Here, a throttle 82 is provided as a component of the bypass pressure detecting means in the bypass passage 66c downstream of each of the control valves 62 to 65.
When 5 is a neutral position or an intermediate movement position (a position between both end movement positions and the neutral position), the hydraulic oil from the second hydraulic pump 52 is returned to the reservoir tank 70 through the throttle 82. The stop 82 is used by the stop 82.
2, the pressure in the bypass passage 66c on the upstream side changes in accordance with the flow rate of the hydraulic oil in the bypass passage 66c, and the pressure in the bypass passage 66c is used as a pressure sensor as a component of the bypass pressure detecting means. The flow rate of the working oil flowing through the bypass passage 66c is detected by detecting the flow rate at 75. For this reason, the throttle 82 and the pressure sensor 75 are also referred to as bypass flow rate detecting means.

Here, the flow rate of the hydraulic oil flowing in the bypass passage 66c is detected by detecting the pressure in the bypass passage 66c by the pressure sensor 74, but the present invention is not limited to this. For example, a bypass passage 66 is provided by a flow sensor (bypass flow rate detecting means).
Alternatively, the flow rate of the hydraulic oil flowing in c may be detected.

The control valves 57-60, 62-65
Are housed in a control unit (not shown). As described above, in the present embodiment, a sufficient hydraulic oil is supplied to the important stick 104 in the operation of the construction machine even at the time of the simultaneous operation with the other work machine 118.
In addition to the hydraulic oil from the second hydraulic pump 52 of the second circuit section 56, the hydraulic oil from the first hydraulic pump 51 of the first circuit section 55 is also supplied to the stick driving hydraulic cylinder 106.

For this reason, the first stick control valve 64 is interposed in the oil passage 66 of the second circuit portion 56 and the first circuit portion 55
The second stick control valve 60 is interposed in the oil passage 61 of the second stick. The first stick control valve 64 is controlled by the proportional control valves 64a and 64b, and the second stick control valve 60 is controlled by the proportional control valves 60a and 60b.
6 can be supplied and discharged.

Similarly, in addition to the hydraulic oil from the first hydraulic pump 51 of the first circuit section 55, a sufficient hydraulic oil is supplied to the boom 103 even during simultaneous operation with another work machine 118. Hydraulic oil from the second hydraulic pump 52 of the second circuit section 56 is also supplied to the boom drive hydraulic cylinder 105. Therefore, the oil passage 6 of the first circuit portion 55
1 is provided with a first boom control valve 59,
A second boom control valve 65 is interposed in the oil passage 66 of the second boom. Then, the first boom control valve 59 is changed to the proportional control valve 59.
a, 59b, and by controlling the second boom control valve 65 with the proportional control valves 65a, 65b, hydraulic oil can be supplied to and discharged from the boom drive hydraulic cylinder 105.

In this embodiment, the oil passage 6 for supplying and discharging the hydraulic oil to and from the stick driving hydraulic cylinder 106 is provided.
A regeneration valve 76 for a stick is interposed in 7, 68 so that a predetermined amount of hydraulic oil can be regenerated from the hydraulic oil discharge side oil passage to the hydraulic oil supply side oil passage. Similarly, boom regeneration valves 77 are also interposed in oil passages 78 and 79 for supplying and discharging hydraulic oil to and from the hydraulic cylinder 105 for boom drive. A predetermined amount of hydraulic oil can be regenerated.

Here, each control valve 57-60, 62-65
Are configured as spool valves as shown in FIG. 3, and each is provided with a plurality of (here, five) throttles. That is, each of the control valves 57 to 60 and 62 to 65
As shown in the figure, the first hydraulic pump 51 and the second hydraulic pump 5
2, a PC throttle 40 interposed in oil passages (operating oil supply passages, PC passages) 61a and 66a communicating the stick 2 with the stick driving hydraulic cylinder 106, the stick driving hydraulic cylinder 106 and the reservoir tank 70. The CT throttle 41 interposed in the oil passages (hydraulic oil discharge passage, CT passage) 66b, 69 that communicates with the first hydraulic pump 51, the second hydraulic pump 52, and the reservoir tank 70. And a bypass passage restrictor 42 interposed in oil passages (bypass passages) 61b and 66c.

In FIG. 3, the stick control valve 60,
Although 64 is in the stick lowered position, the stick control valves 60 and 64 are moved upward in FIG.
Restriction of bypass passage 42 of control valves 60 and 64 for stick
Are disposed in the bypass passages 61b and 66c, the stick control valves 60 and 64 can be set to the neutral position, and the stick control valves 60 and 64 are
Move the stick control valve 60, 6
The PC throttle 40 of FIG. 4 is interposed in the PC passages 61a and 66a, and the C-
By interposing the T throttle 41 in the CT passages 66b and 69, the stick control valves 60 and 64 can be set to the stick raising position.

In setting the diameters of the apertures 40, 41, and 42, all the operation members 54 are fully operated when the operation members 54 are fully operated in order to secure the interlocking of the working machines 118 such as the boom 103 and the stick 104. Work implement 118 is considered to move. The opening areas of the oil passages 61a and 66a that connect the first hydraulic pump 51 and the second hydraulic pump 52 to the stick driving hydraulic cylinder 106 (opening area of the hydraulic oil supply passage, P− C opening area)
Is adjusted.

The opening area of the oil passages 66b and 69 (opening area of the hydraulic oil discharge passage, opening area of the CT opening) of the oil passages 66b and 69 communicating the stick driving hydraulic cylinder 106 and the reservoir tank 70 is adjusted by the CT throttle 41. You. The oil passages 61 b and 6 connecting the first hydraulic pump 51 and the second hydraulic pump 52 to the reservoir tank 70 by the bypass passage restrictor 42.
The opening area of 6c (the opening area of the bypass passage) is adjusted.

In this embodiment, each of the control valves 57 to 60, 6
2 to 65 are in the neutral position when none of the operation members 54 is operated, and the hydraulic pumps 51 and 5
2 is returned to the tank 70 through the bypass passages 61b and 66c. On the other hand, any one of the operation members 54 is operated by the operator, and the control valves 57 to 60, 62 to 6
For example, when the position 5 is set to an intermediate movement position (a position between the both-end movement position and the neutral position), the bypass passages 61b, 66
The opening area of c is narrowed by the bypass passage restrictor 42, and the flow rate of the hydraulic oil returned to the tank 70 through the bypass passages 61b and 66c is reduced, while the PC restrictor 40 is closed.
The opening area of the hydraulic oil supply passage narrowed by the hydraulic oil supply passage is increased.
Hydraulic oil is supplied to 5 to 107, 109l, 109R, and 110, and the opening area of the hydraulic oil discharge passage narrowed by the CT throttle 41 increases, and the hydraulic oil is discharged to the tank 70 through the hydraulic oil discharge passage. Will be.
Thereby, each hydraulic actuator 105-107, 1
09l, 109R, 110 is supplied with hydraulic oil to each of the hydraulic actuators 105-107, 109l, 109R,
110 is activated. Each hydraulic actuator 10
The flow rates of the hydraulic oil supplied to the control valves 57 to 60, 62 to 6 are controlled in accordance with the operation amounts of the operation members 54 by the operator.
5 is controlled by the amount of movement.

Further, each operation member 54 by the operator
When the control valves 57 to 60 and 62 to 65 are set to the maximum movement positions according to the operation amounts of the bypass passages 61b and 66c,
The opening area of the tank 70 is closed, and the hydraulic oil from the hydraulic pumps 51 and 52 is supplied to the tank 70 through the bypass passages 61b and 66c.
On the other hand, the opening area of the hydraulic oil supply passage narrowed by the PC throttle 40 is maximized, and the hydraulic actuators 105 to 107, 1 are connected through the hydraulic oil supply passage.
The operation oil discharged to the tank 70 through the hydraulic oil discharge passage is maximized while the flow rate of the hydraulic oil supplied to the 09l, 109R, 110 is maximized, and the opening area of the hydraulic oil discharge passage narrowed by the CT throttle 41 is also maximized. The oil flow is also maximum. Thereby, each hydraulic actuator 105-1
07, 109l, 109R, 110 will operate at the fastest operating speed.

In this way, the hydraulic oil from the hydraulic pumps 51 and 52 is supplied to the hydraulic actuators 105 to 107 and 10
9l, 109R, 110, which can also be considered as follows. That is, when the operator operates the operation member 54, the control valves 57-60, 62-65 disposed in the hydraulic oil supply passage move accordingly, and the hydraulic actuators 105-107, 1091, 109
While hydraulic oil is supplied to R and 110, control valves 57 to 6
Hydraulic actuators 105-1 through 0,62-65
07, 109l, 109R and 110 are supplied to the tank 7 through the bypass passages 61b and 66c.
It can be thought that it is returned to 0.

In this embodiment, each control valve 57
As shown in FIG. 2, a pilot pump 83 and proportional pressure reducing valves 57a-60
a, 57b-60b, 62a-65a, 62b-65b
And a pilot hydraulic circuit comprising: In FIG. 2, the pilot pump 83 and the proportional pressure reducing valves 57a to 60a, 57b provided in the pilot hydraulic circuit are shown.
60b, 62a-65a, 62b-65b, and the pilot oil pressure is omitted by omitting the pilot oil passage.
Indicated by.

Here, the proportional pressure reducing valves 57a to 60a, 57
Reference numerals b to 60b, 62a to 65a, and 62b to 65b denote solenoid valves, which are operated by operation signals from the controller 1 described later. As a result, the pilot oil pressure from the pilot pump
Each of the control valves 57-
60, 62-65.

With such a configuration, for example, in order to swing the upper swing body 102, the swing operation member 54 d in the operation room 101 is operated, and the pilot oil pressure P from the pilot pump 83 is applied to a pilot oil passage (not shown). Through this, it acts on the swing motor control valve 63 to move the swing motor control valve 63 to a required position. This allows
Supply and discharge of hydraulic oil to and from the swing motor 110 are adjusted, whereby the swing motor 110 is operated.

For example, to turn the upper swing body 102 rightward, the swing motor 110 may be turned clockwise.
In this case, the pilot oil pressure is applied to the swing motor control valve 63 through the pilot oil passage. This allows
The turning motor control valve 63 is set to the right turning position, and the operating oil from the second hydraulic pump 52 of the second circuit portion 56 is supplied to the oil passage 66.
a, 96, the hydraulic oil in the left oil chamber of the swing motor 110 is supplied to the right oil chamber of the swing motor 110,
The oil is discharged to the reservoir tank 70 through the oil passages 97 and 66b. As a result, the turning motor 110 is turned clockwise, and the upper turning body 102 turns right.

Conversely, in order to turn the upper swing body 102 to the left, the swing motor 110 may be turned to the left. In this case, the pilot oil pressure is applied to the swing motor control valve 63 through the pilot oil passage. As a result, the turning motor control valve 63 is turned to the left turning position, and the operating oil from the second hydraulic pump 52 of the second circuit portion 56 is supplied to the oil passage 66.
a, 97, the hydraulic oil in the right oil chamber of the swing motor 110 is supplied to the left oil chamber of the swing motor 110,
The oil is discharged to the reservoir tank 70 through the oil passages 96 and 66b. As a result, the turning motor 110 is turned counterclockwise, and the upper turning body 102 turns left.

Further, in order to maintain the current state of the upper swing body 102, the pilot hydraulic pressure is applied to the swing motor control valve 63 as appropriate to set the spool position of the swing motor control valve 63 to the neutral position (hydraulic supply / discharge). (Road blocking position).
Accordingly, the supply and discharge of hydraulic oil in each oil chamber of the swing motor 110 is stopped, and the upper swing body 102 is held at the current position.

By the way, various sensors are attached to the construction machine configured as described above, and a detection signal from each sensor is sent to a controller 1 described later. For example, an engine 50 for driving the hydraulic pumps 51 and 52 is provided with an engine speed sensor 71, and a detection signal from the engine speed sensor 71 is sent to a controller 1 described later. The controller 1 performs feedback control so that the actual engine speed becomes the target engine speed set by the engine speed setting dial by the operator.

The first hydraulic pump 5 of the first circuit section 55
On the discharge side of the second hydraulic pump 52 of the first and second circuit units 56, pressure sensors (P
/ S-P1) 72 and a pressure sensor (P / S-P2) 73, and detection signals from these pressure sensors 72, 73 are sent to the controller 1 described later.

Further, the downstream side of each of the control valves 57 to 60 of the oil passage 61 as one bypass passage from the hydraulic pump 51 of the first circuit portion 55 to the tank 70 and the second circuit portion 56
A pressure sensor (P / S-N1) 74 as a component of a bypass pressure detecting means is provided downstream of each of the control valves 62 to 65 of an oil passage 66 as one bypass passage leading from the hydraulic pump 51 to the tank 70 of FIG. , Pressure sensor (P / S
-N2) 75, and these pressure sensors 7
The detection signals from 4, 75 are sent to a controller 1 described later.

Further, a pressure sensor (P / S−P) is provided in an oil passage for supplying and discharging hydraulic oil to and from the hydraulic cylinder 105 for boom drive.
BMd) 80 is provided so that the pressure sensor 80 can detect the rod-side pressure (load pressure) of the boom drive hydraulic cylinder 105. And
The detection signal from the pressure sensor 80 is sent to the controller 1 described later.

In the present embodiment, the controller 1 is provided to control the construction machine configured as described above. The controller 1 includes the sensors 71 to 71 described above.
The first hydraulic pump 51, the second hydraulic pump 5 based on the detection signals from 75 and 80 and the electric signal from the operation member 54.
2, each regeneration valve 76, 77, each control valve 57-60, 62-
By outputting an operation signal to the first and second hydraulic pumps 65, 65, the tilt angle control of the first hydraulic pump 51 and the second hydraulic pump 52 and the control valves 57
60, 62 to 65, the position control of each of the regeneration valves 76 and 77, and the like.

Here, as shown in FIG. 1, the controller 1 has a function of processing an electric signal from each operation member 54 in order to control the tilt angles of the first and second hydraulic pumps 51 and 52. Operating member signal processing means 2; first hydraulic pump tilt angle control means 3 as a function of controlling the tilt angle of the first hydraulic pump 51; and a function of controlling the tilt angle of the second hydraulic pump 52 Second hydraulic pump tilt angle control means 4
And is provided. Since the first hydraulic pump tilt angle control means 3 and the second hydraulic pump tilt angle control means 4 both control the discharge flow rate from the hydraulic pump, they are also referred to as pump flow rate control means.

The operation member signal processing means 2 includes, as shown in FIG. 1, the operation members 54a to 54d, 54e-
When the R and 54e-L are operated, each operation member 54a
The moving amounts of the control valves 57 to 60, 62 to 65 are set based on the electric signals corresponding to the operation amounts of the control valves 57 to 60, 62 to 65, and to be described later. It outputs a control signal to the operating member corresponding tilt angle setting means 6, 11.

The operating member signal processing means 2 comprises a plurality of hydraulic actuators 105 to 107, 109R, 109
When L and 110 are operated at the same time, it functions to set the speed balance (flow distribution) between the hydraulic actuators. Here, the flow rate distribution depends on the operation pattern of the plurality of operation members 54a to 54d, 54e-R, and 54e-L and the operation amount of each hydraulic actuator 10 according to the operation amount.
The speed balance (flow rate balance) of 5-107109R, 109L, 110 is set with priority. The priority can be set arbitrarily. For example, boom 1
03, the stick 104, and the bucket 108, when all the operation members are fully operated to operate simultaneously,
The pump discharge flow rate is the maximum flow rate, and the flow rate balance may be set to 50% for the boom, 30% for the stick, and 20% for the bucket.

The first hydraulic pump tilt angle control means 3 is the same as that shown in FIG.
As shown in the figure, the tilt angle setting means 5 corresponding to the bypass pressure,
Operating member corresponding tilt angle setting means 6, speed corresponding pump tilt angle setting means 7, and allowable horsepower corresponding tilt angle setting means 8
And a minimum value selecting means 9 for outputting a pump tilt angle control signal Fp1 to the first hydraulic pump 51.

Among these, the bypass pressure-dependent tilt angle setting means 5 sets the pump tilt angle based on the bypass pressure detection signal. As shown in FIG. 4, the tilt angle setting means 5 corresponding to the bypass pressure detects the pressure of the hydraulic oil in the bypass passage 61b of each of the control valves 57 to 60 which operates according to the operation amount of each of the operation members 54. An output signal (E) is inputted from the pressure sensor 74 as the bypass pressure detecting means 81, 74 which performs the pump tilt angle (pump flow rate) based on a characteristic inversely proportional to the output signal (E). ), A first control signal F-1 as a pump tilt angle control signal is set and output to the speed control corresponding tilt angle setting means 7.

The pump tilt angle control (pump flow rate control) performed on the basis of the characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage 61b is called negative flow control. Here, the substantially inversely proportional characteristic includes not only a curved characteristic as a general inversely proportional characteristic but also, for example, a characteristic that changes linearly. This characteristic is a characteristic of the hydraulic oil in the bypass passage 61b. Any characteristics may be used as long as the pump tilt angle decreases as the pressure increases.

Here, the bypass pressure detecting means 81, 74
Is constituted by a diaphragm 81 and a pressure sensor 74 located upstream of the diaphragm 81. As shown in FIG.
The output signal (E) of the pressure sensor 74 that changes in proportion to the passing flow rate (the sum of the bypass flow rates) (D). The aperture area of the stop 81 is set in advance as a fixed value.

As described above, the bypass pressure detecting means is constituted by the throttle 81 and the pressure sensor 74 because, as described above, the bypass passage throttles 42 of the control valves 57 to 60 are connected in series to the oil passage 61b. When the plurality of operating members 54 are simultaneously operated, the bypass flow rate becomes a sum (D) which is sequentially reduced by each of the control valves 57 to 60, and the sum is (D) to the throttle 81 located downstream of the bypass passage 61b. Since the flow rate is increased, the upstream pressure of the throttle 81 increases as the passing flow rate (the sum of the bypass flow rates) D of the throttle 81 increases, while the passing flow rate of the throttle 81 (the sum of the bypass flow rates) increases. When D decreases, the upstream pressure of the throttle 81 decreases, and the upstream pressure of the throttle 81 that increases or decreases in accordance with the flow rate of the throttle 81 in this manner is detected by the pressure sensor 74. In order to detect.

The tilt angle setting means 6 corresponding to the operation member is provided in FIG.
As shown in (1), control signals (operation amounts of the operation members 54) of the control valves 57 to 60 from the operation member signal processing means 2 are input. The necessary flow rate (necessary pump tilt angle) to be supplied to each of the actuators 105 to 107, 109R through each of the control valves 57 to 60 is based on the characteristic directly proportional to the control signal (the operation amount of each operation member 54) of the valves 57 to 60. This is set as a second control signal F-1 as a pump tilt angle control signal based on the operation member operation amount and output to the speed control corresponding tilt angle setting means 7.

The pump tilt angle control (pump flow rate control) performed based on the characteristic that is substantially directly proportional to the operation amount of the operation member 54 as described above is referred to as positive flow control. Here, the substantially directly proportional characteristic includes not only a linear characteristic as a general directly proportional characteristic but also, for example, a characteristic that changes in a curved shape, and this characteristic increases as the operation amount of the operation member 54 increases. Any characteristics may be used as long as the tilt angle becomes large.

The control signals of the control valves 57 to 60 from the operation member signal processing means 2 (the operation amounts of the operation members 54).
Are, for example, a plurality of hydraulic actuators 105 to 107,
As described above, since the optimal flow distribution is performed by the operating member signal processing means 2 when the 109Rs are simultaneously operated, the control signal corresponding to this flow distribution is transmitted to the operating member corresponding tilt. This is input to the angle setting means 6.

Here, the required flow rate characteristics that are directly proportional to the control signals of the control valves 57 to 60 (the operation amounts of the operation members 54) are set for each of the control valves 57 to 60 as shown in FIG. I have. When a plurality of operation members 54 are operated and control signals to the control valves 57 to 60 are set, required flow rates to be supplied to the control valves 57 to 60 are obtained based on characteristics directly proportional to the control signals. By adding these, the hydraulic pump 5
Pump flow to be discharged by (1) (pump tilt angle) F-
1 is calculated.

The speed-dependent pump tilt angle setting means 7 comprises:
A speed corresponding control signal F1level is set as a pump tilt angle control signal to control the pump tilt angle of the first hydraulic pump 51 for speed control of each of the actuators 105 to 107, 109R. Here, the speed corresponding control signal F1level is controlled according to the amount of operation of each operation member 54 in order to control the speed of each of the hydraulic actuators 105 to 107, 109R under a load condition (pump operation condition) equal to or less than the allowable horsepower. This is a pump tilt angle control signal for controlling the tilt angle (pump flow rate).

Here, as shown in FIG. 6, the speed-dependent pump tilt angle setting means 7 includes a minimum signal selecting means 20.
Required tilt angle comparing means 21 and minimum signal output means 22
And a predetermined value setting means 23, and a required tilt angle output means 24. The speed corresponding control signal F1level is set as a pump tilt angle control signal for controlling the speed of the actuator. 9 is output.

The minimum signal selecting means 20 receives the first control signal F from the bypass pressure corresponding tilt angle setting means 5 as the bypass flow rate based pump tilt angle control signal.
-1 and a second control signal F-1 as a pump tilt angle control signal based on the operating member operation amount from the operating member corresponding tilt angle setting means 6, one of two control signals. This is for selecting a control signal.

The first control signal F-1 is a pump tilt angle control for controlling the pump tilt angle (negative flow control) based on a characteristic inversely proportional to the pressure of the hydraulic oil in the bypass passage 61b. The second control signal F-1 is a pump tilt angle control signal for controlling the pump tilt angle based on a characteristic that is directly proportional to the operation amount of the operation member 54 (positive flow control). Since the signal selection means 20 selects one of the negative flow control and the positive flow control, it is also referred to as a negative control / positive control selection means.

In this case, the minimum signal selecting means 20 outputs the first control signal F from the bypass pressure corresponding tilt angle setting means 5.
-1 is compared with the second control signal F-1 from the operation member corresponding tilt angle setting means 6, and the smaller control signal is output to the minimum signal output means 21 as the minimum control signal Fmin. ing. That is, the minimum signal selecting means 20
When the second control signal F-1 based on the operation member operation amount is smaller than the first control signal F-1 based on the bypass flow rate (F-1 <F-1), the operation member operation amount-based The second control signal F-1 is changed to the minimum control signal Fmin.
When the second control signal F-1 based on the operation member operation amount is larger than the first control signal F-1 based on the bypass flow rate (F-1).
> F-1), the first control signal F-1 based on the bypass flow rate is output to the minimum signal output means 21 as the minimum control signal Fmin.

More specifically, the minimum signal selecting means 20 is based on a characteristic diagram showing the relationship between the load pressure of the working machine (hydraulic actuator) and the working machine speed (working speed) as shown in FIG. By performing the pump tilt angle control, the first control signal F-1 and the second control signal F-1
The pump tilt angle (pump flow rate) is controlled using the control signal for reducing the pump tilt angle (the control signal for reducing the pump flow rate).

As a result, as shown in FIG. 7 (c), when the load pressure decreases, the first control signal F-1 changes in a direction to increase the pump tilt angle, but the second control signal F-1 Since -1 is constant irrespective of the fluctuation of the load pressure,
A signal that reduces the pump tilt angle [ie, the second control signal F
-1] is selectively used. Therefore, when the load pressure decreases, the maximum work machine speed (pump flow rate) does not fluctuate even if the load pressure fluctuates because it is controlled by the second control signal F-1.

On the other hand, as shown in FIG. 7 (c), when the load pressure increases, the first control signal F-1 changes in a direction to decrease the pump tilt angle, while the second control signal F-
1 is constant irrespective of the variation of the load pressure, the first control signal F-1 is smaller than the second control signal F-1, and the signal in which the pump tilt angle is small [namely, the first control signal F-1] Control signal F-1] is selectively used. Therefore, the working machine speed decreases as the load pressure increases,
There is an advantage that the operator can sense the magnitude of the load (load-sensitive feeling).

As described above, the pump tilt angle control is performed based on the characteristics as shown in FIG.
For the following reasons. Here, FIG. 7A shows the load (load pressure applied to the working machine) W and the working machine when the pump tilt angle control is performed using the first control signal F-1 which is inversely proportional to the bypass flow rate. It is a figure which shows the relationship with speed (pump tilt angle, pump flow rate). In FIG. 7A, the broken line indicates the expected speed of the working machine according to the operation amount of the operation member 54.

As described above, the bypass flow rate fluctuates under the influence of the load pressure.
The pump flow rate (pump tilt angle) controlled based on the control signal F-1 of FIG. Therefore, the relationship between the work pressure and the load pressure is shown in FIG.
As shown in (a), the working machine speed (pump tilt angle, pump flow rate) constantly fluctuates with the fluctuation of the load pressure.

Therefore, in a working machine in which the load pressure fluctuates easily (for example, a turning system mainly composed of an inertial load), the working machine speed also fluctuates. Easy to do. In other words, a change in the pump flow rate (pump tilt angle) controlled by a signal based on the bypass flow rate, which fluctuates according to the load pressure, promotes the hunting phenomenon.

On the other hand, when the pump tilt angle control is performed using the first control signal F-1 inversely proportional to the bypass flow rate as described above, the viscous load whose load pressure changes relatively stably is mainly used. In the excavation work or the like, when the load W increases, the speed of the work machine decreases, and there is an advantage that the operator can sense the magnitude of the load (load-sensitive feeling).

On the other hand, the relationship between the load pressure and the work implement speed when the second control signal F-1 which is directly proportional to the operation amount of each operation member 54 is used is as shown in FIG. 7B. That is, the pump flow rate (pump tilt angle) is controlled based on the signal from each operation member 54 and is independent of the fluctuation of the load pressure. Therefore, the working machine speed (pump flow rate) is shown in FIG. As shown, it is constant within the allowable horsepower range.

In this case, since there is no influence of the fluctuation of the load pressure, problems such as a sudden change in the working machine speed and hunting do not occur, but on the other hand, the operator can sense the magnitude of the load (load-sensitive feeling). There is no advantage. For this reason, in this embodiment, in order to be able to enjoy both the advantages of the positive flow control and the advantages of the negative flow control, FIG.
The pump tilt angle control is performed based on the characteristics shown in FIG.

As a result, it is possible to suppress a rapid increase in the working machine speed due to the decrease in the load W and a hunting phenomenon induced by the increase, and to ensure a load-sensitive feeling as the load W increases. You can do it. Such control is used for controlling the pump tilt angle under the condition that each operating member 54 is fixed at a constant value near the middle position of the operating range for the purpose of obtaining a medium working machine speed. Are suitable.

The required tilt angle comparing means 21 receives the second control signal F-1 based on the operating member operation amount from the operating member corresponding tilt angle setting means 6 and the predetermined value set by the predetermined value setting means 23. F1 allow, and outputs the comparison result to the minimum signal output means 22 and the required tilt angle output means 24. Thereby, what kind of work the operator is requesting is determined, and the control signal Fmin selected by the minimum signal selecting means 20 and
Any one of the second control signal F-1 and the second control signal F-1 set by the operating member corresponding tilt angle setting means 6 is used as the pump tilt angle control signal.

Since the second control signal F-1 based on the operation member operation amount is equivalent to the pump tilt angle corresponding to the operation amount of the operation member 54 by the operator, the required tilt angle requested by the operator is obtained. A pump tilt angle control signal corresponding to the shift angle is obtained. Here, the required tilt angle comparing means 21
Is that the second control signal F-1 from the operation member corresponding tilt angle setting means 6 is larger than the predetermined value F1allow set by the predetermined value setting means 23 (F-1> F1all).
ow), the result of the determination is output to the minimum signal output means 22, while the predetermined value F1allow set by the predetermined value setting means 23 is controlled by the second control from the operation member corresponding tilt angle setting means 6. If it is determined that the signal is larger than the signal F-1 (F-1 <F1allow), the result of the determination is output to the required tilt angle output means 24.

As described above, the second control signal F-1 corresponding to the tilt angle required by the operator is set to the predetermined value F1allow.
In the following cases, the second control signal F-1 is selected regardless of the first control signal F-1 because the second control signal F-1 is selected by the hydraulic actuator 105. Speed control signal F11 as a pump tilt angle control signal for speed control of 107, 109R
By performing pump tilt angle (pump flow rate) control as an ever, it is possible to suppress a change in work machine speed (work speed) due to pump control due to a load change in a fine operation range. is there. That is, the second control signal F-1 based on the operation member operation amount is independent of the fluctuation of the load pressure of the work implement (hydraulic actuator).
If the operation amount of the operation member is constant, the load W is constant even if it fluctuates. Therefore, by performing the pump tilt angle control using the second control signal F-1, as shown in FIG. 7D. Thus, even if the load W fluctuates, the work machine speed (pump flow rate,
The pump tilt angle) can be kept constant, and a change in the working machine speed (work speed) caused by the pump tilt angle control due to the load fluctuation in the fine operation range can be suppressed. In FIG. 7D, a broken line indicates a predetermined value F1all.
It shows the working machine speed with respect to the load W when the pump tilt angle control is performed using ow as the pump tilt angle control signal.

This is suitable for a case where the operation members (hydraulic actuators) are fixed at a constant speed within an operation range equal to or less than a predetermined value and a work machine (hydraulic actuator) is operated at a very low speed such as a suspending operation and the speed does not change. ing. By the way, the predetermined value setting means 23 determines the pump tilt angle (pump flow rate) as shown in FIG.
Of the pump discharge pressure (allowable pump flow rate) F1w at the allowable maximum pressure point Pmax of the pump discharge pressure in the allowable horsepower characteristic (horsepower limit allowable value) W1 of the following formula (1). Predetermined value F1allo
w is set. The predetermined value F1 allow
Is set in advance.

Here, the pump allowable tilt angle (pump allowable flow rate) F1w is obtained by the following equation. F1w = W1 ÷ Pmax As described above, the predetermined value F1allow is set as a value corresponding to an arbitrary pump tilt angle equal to or smaller than the pump allowable tilt angle F1w because the pump control accompanying the load fluctuation in the fine operation range. This is to suppress a change in the working machine speed due to the above.

The setting of the predetermined value F1allow is not limited to this, and can be arbitrarily set according to the characteristics of various working machines (tools). The minimum signal output unit 22 outputs the minimum control signal Fmin from the minimum signal selection unit 20 to the minimum value selection unit 9 in accordance with the result of the determination by the required tilt angle comparison unit 21. That is,
The minimum signal output unit 22 permits the output of the minimum control signal Fmin from the minimum signal selection unit 20 to the minimum value selection unit 9 according to the result of the determination by the required tilt angle comparison unit 21.

For this reason, the second control signal F-1 based on the operation member operation amount is larger than the predetermined value F1allow by the required tilt angle comparison means 21 (F-1> F1allow). Is determined, the result of the determination is input. When this signal is input, the minimum control signal Fmin from the minimum signal selecting means 20 is set to a speed corresponding to the speed control of the actuator. The control signal F1level is output to the minimum value selecting means 9.

In the required tilt angle output means 24, the predetermined value F1allow is larger than the second control signal F-1 based on the operating member operation amount by the required tilt angle comparing means 21 (F
-1 <F1allow), the result of the determination is input, and in response to this, the second control signal F-1 based on the operation member operation amount is changed to a speed-related control signal F1level for controlling the speed of the actuator. Is output to the minimum value selecting means 9.

The allowable horsepower corresponding tilt angle setting means 8 sets an allowable horsepower corresponding control signal F1power based on the allowable horsepower limit as a pump tilt angle control signal for controlling the tilt angle of the first hydraulic pump 51. And outputs the allowable horsepower corresponding control signal F1power to the minimum value selecting means 9 described later. Here, the permissible horsepower restriction-based control signal F1power based on the permissible horsepower restriction is a pump tilt angle control signal of an upper limit that is limited according to the permissible horsepower of the engine 50 that drives the first hydraulic pump 51. In other words, the allowable horsepower corresponding control signal F1power based on the allowable horsepower limit is obtained by controlling the pump tilt angle of the first hydraulic pump 51 in accordance with the speed corresponding control signal F1level selected by the speed corresponding pump tilt angle setting means 7. A pump tilt angle control signal for controlling the pump tilt angle (pump flow rate) so that the load W applied to the engine 50 for driving the first hydraulic pump 51 does not exceed the allowable horsepower of the engine 50.

Therefore, the allowable horsepower corresponding tilt angle setting means 8
As shown in FIG. 8, an allowable horsepower storage unit 8A that stores a preset allowable horsepower based on the engine horsepower of the engine 50 that drives the first hydraulic pump 51, and an allowable horsepower corresponding tilt angle calculation unit 8B, and a pump discharge pressure signal detected by the pressure sensor 72 is input to the allowable horsepower corresponding tilt angle calculation unit 8B.

Then, the allowable horsepower corresponding tilt angle calculating section 8B
Is the allowable horsepower W1 from the pump allowable horsepower storage unit 8A,
Based on the pump discharge pressure P1 from the pressure sensor 72, an allowable horsepower limit-based control signal (allowable flow rate control signal) F1power based on the allowable horsepower limit is calculated by the following equation. F1power = W1 ÷ P1 The allowable horsepower limit-based allowable horsepower-based control signal F1power calculated in this manner is an allowable horsepower-based control signal F1power as shown in FIG.
This is represented as a characteristic diagram in which r is associated with the pump discharge pressure P1. Note that, in the characteristic diagram shown in FIG. 8, the straight line portion indicated by the symbol A indicates the maximum tilt angle (maximum discharge flow rate) of the pump.

The minimum value selecting means 9 includes a speed-dependent control signal F1level set by the speed-dependent pump tilt angle setting means 7 and an allowable horsepower-dependent control signal F1power set by the allowable horsepower tilt angle setting means 8. And selects a control signal that reduces the pump tilt angle (a control signal that decreases the pump flow rate), sets this as the final pump tilt angle control signal Fp1, and sets the first hydraulic pump 51 Output to

The second hydraulic pump tilt angle control means 4 is configured in the same manner as the first hydraulic pump tilt angle control means 3 described above. In other words, the second hydraulic pump tilt angle control means 4 is configured as shown in FIG.
As shown in FIG.
An operating member corresponding tilt angle setting means 11, a speed corresponding pump tilt angle setting means 12, an allowable horsepower corresponding tilt angle setting means 13, and a minimum value selecting means 14,
It outputs the pump tilt angle control signal Fp2 to the second hydraulic pump 52.

The bypass pressure setting tilt angle setting means 10 sets the pump tilt angle based on the bypass pressure detection signal. The bypass pressure setting tilt angle setting means 5 is shown in FIG. Thus, the bypass passage 6 of each of the control valves 62 to 65 that operates according to the operation amount of each of the operation members 54
The output signal (E) from the pressure sensor 75 as the bypass pressure detecting means 82, 75 for detecting the pressure of the hydraulic oil in 6c.
The pump tilt angle (pump flow rate) is determined based on a characteristic inversely proportional to the output signal (E).
The first control signal F-2 is set as a pump tilt angle control signal to control the tilt angle, and is output to the speed control corresponding tilt angle setting means 12.

The pump tilt angle control (pump flow rate control) performed on the basis of the characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage 66c is called negative flow control. Here, the characteristic that is approximately inversely proportional includes not only a curved characteristic as a general inverse proportional characteristic but also, for example, a characteristic that changes linearly, and this characteristic is a characteristic of the hydraulic oil in the bypass passage 66c. What is necessary is just a characteristic in which the pump tilt angle decreases as the pressure increases.

Here, the bypass pressure detecting means 82, 75
Is constituted by a diaphragm 82 and a pressure sensor 75 located upstream of the diaphragm 82. As shown in FIG.
The output signal (E) of the pressure sensor 75 that changes in proportion to the passing flow rate (the sum of the bypass flow rates) (D). The aperture area of the stop 82 is set in advance as a fixed value.

As described above, the bypass pressure detecting means is constituted by the throttle 82 and the pressure sensor 75. As described above, the bypass passage throttles 42 of the control valves 62 to 65 are connected in series to the oil passage 66c. When the plurality of operating members 54 are simultaneously operated, the bypass flow rate becomes a sum (D) which is sequentially reduced by each of the control valves 62 to 65 to the throttle 82 located downstream of the bypass passage 66c. Since the inflow is performed, the upstream pressure of the throttle 82 increases as the passing flow rate (the sum of the bypass flow rates) D of the throttle 82 increases, while the passing flow rate of the throttle 82 (the sum of the bypass flow rates) increases. When D decreases, the pressure on the upstream side of the throttle 82 decreases, and the pressure on the upstream side of the throttle 82, which increases or decreases in accordance with the flow rate through the throttle 82, is detected by the pressure sensor 75. In order to detect.

As shown in FIG. 5, the control signal for each of the control valves 62 to 65 (the operation amount of each of the operation members 54) from the operation member signal processing means 2 is input to the operation member corresponding tilt angle setting means 11, as shown in FIG. These control signals are used to control each of the control valves 62 to 65 based on a characteristic that is directly proportional to the control signal of each of the control valves 62 to 65 (the operation amount of each of the operation members 54).
The required flow rate (required pump tilt angle) to be supplied to each of the actuators 106, 109L, and 110 is obtained as a second control signal F-2 as a pump tilt angle control signal based on the operation member operation amount. Is output to the speed control corresponding tilt angle setting means 12.

Note that the pump tilt angle control (pump flow rate control) performed based on the characteristic substantially directly proportional to the operation amount of the operation member 54 is called positive flow control. Here, the substantially directly proportional characteristic includes not only a linear characteristic as a general directly proportional characteristic but also, for example, a characteristic that changes in a curved shape, and this characteristic increases as the operation amount of the operation member 54 increases. Any characteristics may be used as long as the tilt angle becomes large.

The control signals of the control valves 62 to 65 from the operation member signal processing means 2 (the operation amounts of the operation members 54).
Is, for example, a plurality of hydraulic actuators 106 and 109
When L and 110 are operated simultaneously, as described above,
Since the optimal flow distribution is performed by the operation member signal processing means 2, a control signal corresponding to the flow distribution is input to the operation member corresponding tilt angle setting means 11.

Here, the required flow rate characteristics that are directly proportional to the control signals of the control valves 62 to 65 (the operation amounts of the operation members 54) are set for each of the control valves 62 to 65 as shown in FIG. I have. Then, when a plurality of operation members 54 are operated to set control signals to the control valves 62 to 65, a required flow rate to be supplied to the control valves 62 to 65 is obtained based on a characteristic directly proportional to the control signal. By adding these, the hydraulic pump 5
2. Pump flow rate (pump tilt angle) F-
2 is calculated.

Speed-dependent pump tilt angle setting means 12
Sets the speed corresponding control signal F2level as a pump tilt angle control signal in order to control the pump tilt angle of the second hydraulic pump 52 for speed control of each of the actuators 106, 109L, 110. Here, in order to control the speed of each of the hydraulic actuators 106, 109L, 110 under a load condition (pump operating condition) that is equal to or less than the allowable horsepower, the speed corresponding control signal F2level corresponds to the pump amount corresponding to the operation amount of each operation member 54. This is a pump tilt angle control signal for controlling the tilt angle (pump flow rate).

Here, as shown in FIG. 6, the speed-dependent pump tilt angle setting means 12 is provided with a minimum signal selecting means 20.
Required tilt angle comparing means 21 and minimum signal output means 22
And a predetermined value setting means 23 and a required tilt angle output means 24, and sets a speed corresponding control signal F2level as a pump tilt angle control signal for controlling the speed of the actuator, and sets a minimum value selecting means. 14.

The minimum signal selection means 20 receives the first control signal F as the bypass flow rate-based pump displacement angle control signal from the bypass pressure corresponding displacement angle setting means 10.
-2 and a second as a pump tilt angle control signal based on the operation member operation amount from the operation member corresponding tilt angle setting means 11.
One control signal is selected from the two control signals of the control signal F-2.

Note that the first control signal F-2 is a pump tilt angle control for controlling the pump tilt angle (negative flow control) based on a characteristic that is inversely proportional to the flow rate of the hydraulic oil in the bypass passage 66c. The second control signal F-2 is a pump tilt angle control signal for controlling the pump tilt angle based on a characteristic that is directly proportional to the operation amount of the operation member 54 (positive flow control). Since the signal selection means 20 selects one of the negative flow control and the positive flow control, it is also referred to as a negative control / positive control selection means.

Here, the minimum signal selecting means 20 includes a first control signal F-2 from the bypass pressure setting tilt angle setting means 10 and a second control signal from the operating member corresponding tilt angle setting means 11. Compared with F-2, the smaller control signal is output to the minimum signal output means 21 as the minimum control signal Fmin. That is, the minimum signal selecting means 20 outputs the second control signal F-
2 is smaller than the first control signal F-2 based on the bypass flow rate (F-2 <F-2), the second control signal F-2 based on the operation member operation amount is changed to the minimum control signal Fm.
in to the minimum signal output means 21 when the second control signal F-2 based on the operation member operation amount is larger than the first control signal F-2 based on the bypass flow rate (F
-2> F-2), the first control signal F-2 based on the bypass flow rate is output to the minimum signal output means 21 as the minimum control signal Fmin.

More specifically, the minimum signal selecting means 20 is based on a characteristic diagram showing the relationship between the load pressure of the working machine (hydraulic actuator) and the working machine speed (working speed) as shown in FIG. By performing the pump tilt angle control, the first control signal F-2 and the second control signal F-2 are controlled.
The pump tilt angle (pump flow rate) is controlled using the control signal for reducing the pump tilt angle (the control signal for reducing the pump flow rate).

As a result, as shown in FIG. 7C, when the load pressure decreases, the first control signal F-2 changes in a direction to increase the pump tilt angle, but the second control signal F-2 changes. -2 is constant irrespective of the fluctuation of the load pressure,
A signal that reduces the pump tilt angle [ie, the second control signal F
-2] is selectively used. Accordingly, when the load pressure decreases, the maximum work machine speed (pump flow rate) does not change even if the load pressure changes because the control is performed by the second control signal F-2.

On the other hand, as shown in FIG. 7 (c), when the load pressure increases, the first control signal F-2 changes in a direction to decrease the pump tilt angle, but the second control signal F-
2 is constant irrespective of the change in load pressure, the first control signal F-2 becomes smaller than the second control signal F-2, and the signal in which the pump tilt angle becomes small [ie, the first control signal F-2 becomes smaller. Is selectively used. Therefore, the working machine speed decreases as the load pressure increases,
There is an advantage that the operator can sense the magnitude of the load (load-sensitive feeling).

As described above, the pump tilt angle control is performed based on the characteristics as shown in FIG.
For the following reasons. Here, FIG. 7A shows the load (load pressure applied to the working machine) W and the working machine when the pump tilt angle control is performed using the first control signal F-2 which is inversely proportional to the bypass flow rate. It is a figure which shows the relationship with speed (pump tilt angle, pump flow rate). In FIG. 7A, the broken line indicates the expected speed of the working machine according to the operation amount of the operation member 54.

As described above, since the bypass flow rate fluctuates under the influence of the load pressure, the first flow rate based on the bypass flow rate is changed.
The pump flow rate (pump tilt angle) controlled based on the control signal F-2 of FIG. Therefore, the relationship between the work pressure and the load pressure is shown in FIG.
As shown in (a), the working machine speed (pump tilt angle, pump flow rate) constantly fluctuates with the fluctuation of the load pressure.

Therefore, in a working machine in which the load pressure fluctuates easily (for example, a turning system mainly composed of an inertial load), the working machine speed also fluctuates, and as a result, problems such as hunting occur. Easy to do. In other words, a change in the pump flow rate (pump tilt angle) controlled by a signal based on the bypass flow rate, which fluctuates according to the load pressure, promotes the hunting phenomenon.

On the other hand, when the pump tilt angle control is performed using the first control signal F-2 inversely proportional to the bypass flow rate as described above, the viscous load whose load pressure changes relatively stably is mainly used. In the excavation work or the like, when the load W increases, the speed of the work machine decreases, and there is an advantage that the operator can sense the magnitude of the load (load-sensitive feeling).

On the other hand, the relationship between the load pressure and the working machine speed when the second control signal F-2 which is directly proportional to the operation amount of each operation member 54 is used is as shown in FIG. 7B. That is, the pump flow rate (pump tilt angle) is controlled based on the signal from each operation member 54 and is independent of the fluctuation of the load pressure. Therefore, the working machine speed (pump flow rate) is shown in FIG. As shown, it is constant within the allowable horsepower range.

In this case, since there is no influence of the fluctuation of the load pressure, problems such as a sudden change of the working machine speed and hunting do not occur, but on the other hand, the operator can sense the magnitude of the load (load-sensitive feeling). There is no advantage. For this reason, in this embodiment, in order to be able to enjoy both the advantages of the positive flow control and the advantages of the negative flow control, FIG.
The pump tilt angle control is performed based on the characteristics shown in FIG.

As a result, it is possible to suppress a rapid increase in the speed of the working machine as the load W decreases and a hunting phenomenon induced thereby, and to secure a load-sensitive feeling as the load W increases. You can do it. Such control is used for controlling the pump tilt angle under the condition that each operating member 54 is fixed at a constant value near the middle position of the operating range for the purpose of obtaining a medium working machine speed. Are suitable.

The required tilt angle comparing means 21 is provided with the second operation amount base based on the operating member operation amount from the operating member corresponding tilt angle setting means 11.
Is compared with the predetermined value F2allow set by the predetermined value setting means 23, and the result of the comparison is output to the minimum signal output means 22 and the required tilt angle output means 24. Thus, it is determined what kind of work the operator is requesting, and the control signal Fmin selected by the minimum signal selecting means 20 is determined.
One of the control signal and the second control signal F-2 set by the operation member corresponding tilt angle setting means 11 is used as the pump tilt angle control signal.

Since the second control signal F-2 based on the operation member operation amount is equivalent to the pump tilt angle corresponding to the operation amount of the operation member 54 by the operator, the required inclination required by the operator is required. A pump tilt angle control signal corresponding to the shift angle is obtained. Here, the required tilt angle comparing means 21
Is that the second control signal F-2 from the operating member corresponding tilt angle setting means 11 is larger than the predetermined value F2allow set by the predetermined value setting means 23 (F-2> F2al).
If it is determined as “low”, the result of the determination is output to the minimum signal output means 22, while the predetermined value F2allow set by the predetermined value setting means 23 is controlled by the second control from the operation member corresponding tilt angle setting means 11. When it is determined that the signal is larger than the signal F-2 (F-2 <F2allow), the result of the determination is output to the required tilt angle output means 24.

As described above, the second control signal F-2 corresponding to the tilt angle required by the operator is set to the predetermined value F2allow.
In the following case, the second control signal F-2 is selected regardless of the first control signal F-2 because the second control signal F-2 is selected by the hydraulic actuator 106. , 109L, and 110L, a speed-related control signal F21 as a pump tilt angle control signal for speed control
By performing pump tilt angle (pump flow rate) control as an ever, it is possible to suppress a change in work machine speed (work speed) due to pump control due to a load change in a fine operation range. is there. That is, the second control signal F-2 based on the operation member operation amount is independent of the change in the load pressure of the work implement (hydraulic actuator).
If the operation amount of the operation member is constant, it is constant even if the load W fluctuates. Therefore, by performing pump tilt angle control using the second control signal F-2, it is shown in FIG. 7D. Thus, even if the load W fluctuates, the work machine speed (pump flow rate,
The pump tilt angle) can be kept constant, and a change in the working machine speed (work speed) caused by the pump tilt angle control due to the load fluctuation in the fine operation range can be suppressed. In FIG. 7D, a broken line indicates a predetermined value F2all.
It shows the working machine speed with respect to the load W when the pump tilt angle control is performed using ow as the pump tilt angle control signal.

This is suitable for the case where each operating member 54 is fixed at an operating range equal to or less than a predetermined value and a work machine (hydraulic actuator) is operated at a very low speed such as a suspending operation and the speed does not change. ing. By the way, the predetermined value setting means 23 determines the pump tilt angle (pump flow rate) as shown in FIG.
Of the pump discharge pressure (allowable pump flow rate) F2w at the allowable maximum pressure point Pmax of the pump discharge pressure in the allowable horsepower characteristic (horsepower limit allowable value) W2 of the above (corresponding to an arbitrary pump tilt angle (predetermined tilt angle)). Predetermined value F2 allo
w is set. Note that the predetermined value F2allow
Is set in advance.

Here, the pump allowable tilt angle (pump allowable flow rate) F2w is obtained by the following equation. F2w = W2 ÷ Pmax As described above, the predetermined value F2allow is set as a value corresponding to an arbitrary pump tilt angle equal to or smaller than the pump allowable tilt angle F2w because the pump control accompanying the load fluctuation in the fine operation range. This is to suppress the change in the speed of the working machine due to the above.

The setting of the predetermined value F2allow is not limited to this, and can be arbitrarily set according to the characteristics of various working machines (tools). The minimum signal output unit 22 outputs the minimum control signal Fmin from the minimum signal selection unit 20 to the minimum value selection unit 14 according to the result of the determination by the required tilt angle comparison unit 21. That is, the minimum signal output unit 22 permits the output of the minimum control signal Fmin from the minimum signal selection unit 20 to the minimum value selection unit 14 according to the result of the determination by the required tilt angle comparison unit 21.

For this reason, the second control signal F-2 based on the operation member operation amount is larger than the predetermined value F2allow (F-2> F2allow) by the required tilt angle comparing means 21 to the minimum signal output means 22. Is determined, the result of the determination is input. When this signal is input, the minimum control signal Fmin from the minimum signal selecting means 20 is set to a speed corresponding to the speed control of the actuator. The control signal is output to the minimum value selecting means 14 as a control signal F2level.

In the required tilt angle output means 24, the predetermined value F2allow is larger than the second control signal F-2 based on the operation member operation amount by the required tilt angle comparison means 21 (F
-2 <F2allow), the result of the determination is input, and in response to this, the second control signal F-2 based on the operation member operation amount is changed to a speed-related control signal F2level for controlling the speed of the actuator. Is output to the minimum value selecting means 14.

The permissible horsepower corresponding tilt angle setting means 13 sets the second
An allowable horsepower limit-based control signal F2power is set as a pump tilt angle control signal for controlling the tilt angle of the hydraulic pump 52, and the allowable horsepower corresponding control signal F2power is set to a minimum value selection unit 14 described later. Output to Here, the allowable horsepower corresponding control signal F2power based on the allowable horsepower limit is set to the second hydraulic pump 5
2 is an upper limit pump tilt angle control signal that is limited according to the allowable horsepower of the engine 50 that drives the engine 2. That is, the allowable horsepower corresponding control signal F2power based on the allowable horsepower restriction
When the pump tilt angle of the second hydraulic pump 52 is controlled in accordance with the speed corresponding control signal F2level selected by the speed corresponding pump tilt angle setting means 12, the engine 50 that drives the second hydraulic pump 52 This is a pump tilt angle control signal for controlling the pump tilt angle (pump flow rate) so that the load W does not exceed the allowable horsepower of the engine 50.

For this reason, the allowable horsepower corresponding tilt angle setting means 1
8, an allowable horsepower storage unit 8A that stores a preset allowable horsepower based on the engine horsepower of the engine 50 that drives the second hydraulic pump 52, as shown in FIG. And a pump discharge pressure signal detected by the pressure sensor 73 is input to the allowable horsepower corresponding tilt angle calculation unit 8B.

Then, the allowable horsepower corresponding tilt angle calculating section 8B
Is the allowable horsepower W2 from the pump allowable horsepower storage unit 8A,
Based on the pump discharge pressure P2 from the pressure sensor 73, an allowable horsepower limit-based control signal (allowable flow rate control signal) F2power based on the allowable horsepower limit is calculated by the following equation. F2power = W2 ÷ P2 The allowable horsepower limit-based allowable horsepower-based control signal F2power calculated in this manner is an allowable horsepower-based control signal F2power as shown in FIG.
This is represented as a characteristic diagram in which r is associated with the pump discharge pressure P2. Note that, in the characteristic diagram shown in FIG. 8, the straight line portion indicated by the symbol A indicates the maximum tilt angle (maximum discharge flow rate) of the pump.

The minimum value selecting means 14 comprises a speed-dependent control signal F2level set by the speed-dependent pump tilt angle setting means 12 and an allowable horsepower-dependent control signal F2pow set by the allowable horsepower tilt angle setting means 13.
er, a control signal that reduces the pump tilt angle (a control signal that reduces the pump flow rate) is selected and set as the final pump tilt angle control signal Fp2,
The output is to the second hydraulic pump 52.

Although the description has been made here assuming that the pump flow rate and the pump tilt angle correspond to each other, the conversion of the pump flow rate and the pump tilt angle is performed by the engine speed sensor (engine speed detecting means) 71. This is performed by the controller 1 based on the detected engine speed. By the way, in this embodiment, as described above, the hydraulic actuators 105 to 107, 109R, 109L, and 110 are provided as standard hydraulic actuators (first hydraulic actuators).
As shown in FIG. 2,
These standard hydraulic actuators 105-107,
Optional hydraulic actuator (second hydraulic actuator) 1 in addition to 109R, 109L, 110
005,1006. In FIG. 2,
Although the additional hydraulic actuator 1005 is shown as a hydraulic cylinder and the additional hydraulic actuator 1006 is shown as a hydraulic motor, the additional hydraulic actuator is not limited to these.

In addition to the hydraulic circuit for supplying and discharging the hydraulic oil to and from the standard equipped hydraulic actuators 105 to 107, 109R, 109L and 110 as described above, the hydraulic oil is supplied to the additional hydraulic actuators 1005 and 1006. A hydraulic circuit including supply / discharge control valves 1001 and 1002 for additional hydraulic actuators for supplying / discharging is additionally provided.

First, the standard hydraulic actuator will be described. Standard equipped hydraulic actuator 105-10
In the hydraulic circuit (standard hydraulic circuit) for supplying and discharging the hydraulic oil to and from the hydraulic pumps 7, 109R, 109L, 110, the hydraulic pumps 51, 52 and the standard hydraulic actuators 105 to 107, 109R, 109L, Reference numeral 110 denotes an oil passage (first hydraulic oil supply passage, hydraulic oil supply / discharge passage) 61,
66, and operating members (first operating members, operating members for hydraulic actuators as standard equipment) 54a to 54a.
Each control valve (first control valve, control valve for a standard hydraulic actuator) 57 to 57 interposed in the oil passages 61, 66 based on electric signals corresponding to the operation amounts of the 54d, 54e-R, 54e-L. By controlling the amount of movement of each of the hydraulic actuators 105 to 107, 109R,
The supply and discharge of hydraulic oil to and from 109L and 110 are controlled. Also, the first control valves 57-60, 62-65
Flow rate detecting means 74, 8 to detect the flow rate of the hydraulic oil in the oil passages (bypass paths) 61b, 66c on the downstream side of
1,75,82 are also provided.

Further, the hydraulic pump 5
As described above, the pump tilt angle control of the first and second pumps 52 is based on the characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passages 61b and 66c detected by the bypass flow rate detectors 74, 81, 75 and 82. A control signal for controlling the pump flow rate based on a characteristic that is substantially directly proportional to the first control signal for controlling the pump flow rate and the operation amounts of the standard-equipped hydraulic actuator operation members 54a to 54d, 54e-R, and 54e-L. By selecting one of the second control signals, the discharge flow rate of the hydraulic oil from the hydraulic pumps 51 and 52 is controlled.

On the other hand, as for the additional hydraulic actuator, as shown in FIG. 2, a hydraulic circuit (additional hydraulic circuit) for supplying and discharging hydraulic oil to and from the additional hydraulic actuator is provided as standard equipped hydraulic actuators 105 to 107,
It is provided separately from a standard equipment hydraulic circuit for supplying and discharging hydraulic oil to and from 109R, 109L, and 110. That is, the hydraulic pumps 51 and 52 and the additional hydraulic actuator 1
005 and 1006, as shown in FIG. 2, hydraulic pumps 51 and 52 and hydraulic actuators 105 to 10 as standard equipment.
7, 109R, 109L, 110, oil passage 6
Control valves 57 to 60, 62 to 65 interposed in 1, 66
Are connected via additional hydraulic actuator oil passages (second hydraulic oil supply passage, hydraulic oil supply / discharge passage) 1007 and 1008 branched from the upstream side (directly downstream of the hydraulic pump) of the oil pump. Control valves for additional hydraulic actuators (second control valve, supply / discharge control valve for additional hydraulic actuators) 100 for controlling supply / discharge of hydraulic oil to / from additional hydraulic actuators 1005 and 1006
1,1002 are interposed.

Then, the additional hydraulic actuator 100
5, 1006, the additional hydraulic actuator oil passages 1007, 100 are operated based on electric signals corresponding to the operation amounts of the additional hydraulic actuator operation members (second operation members) 54f, 54g operated by the operator.
Supply / discharge control valve 1 for additional hydraulic actuator interposed in 8
The amount of movement of 001 and 1002 is controlled, and the supply and discharge of hydraulic oil to and from the additional hydraulic actuators 1005 and 1006 are controlled. Note that reference numerals 1001a and 1001
Reference numerals 01b, 1002a, and 1002b denote proportional pressure reducing valves (solenoid valves) for controlling the supply / discharge control valves 1001 and 1002 for the additional hydraulic actuator, respectively. 5
Proportional pressure reducing valve 57 for controlling 7 to 60, 62 to 65
a to 60a, 57b to 60b, 62a to 65a, 62b
To 65b.

Unlike the hydraulic circuit for supplying and discharging hydraulic oil to and from the above-mentioned standard hydraulic actuators 105 to 107, 109R, 109L and 110, the hydraulic circuit is provided via supply and discharge control valves 1001 and 1002 for additional hydraulic actuators. There is no bypass passage for returning hydraulic oil not supplied to the additional hydraulic actuators 1005 and 1006 to the tank 70, and the additional hydraulic actuator oil passage 1
No bypass flow rate detecting means for detecting the flow rate of hydraulic oil downstream of the supply / discharge control valves 1001 and 1002 for additional hydraulic actuators interposed in 007 and 1008 is provided. That is, the additional hydraulic actuators 1005, 1
The hydraulic circuit for supplying and discharging hydraulic oil to and from 006 is not designed to perform negative flow control. This allows the supply / discharge control valve 1 for the additional hydraulic actuator to perform negative flow control.
001 and 1002 do not need to be installed in series with the supply / discharge control valves 57 to 60 and 62 to 65 for the standard hydraulic actuators.
This increases the degree of freedom of the installation position of the supply / discharge control valves 1001 and 1002 for additional hydraulic actuators for controlling the supply / discharge of hydraulic oil to / from the hydraulic pump. In order to operate the additional hydraulic actuators 1005 and 1006, positive flow control can be performed as pump flow control, as described later.

The bypass passage 6 of the standard hydraulic circuit
1b and 66c have throttles 81 and 8 as bypass flow rate detecting means interposed in the bypass passages 61b and 66c.
2, a bypass passage 61 as shown in FIG.
b, 66c are additionally provided with bypass passage shutoff valves (control valve, electromagnetic switching valve, bypass passage communication shutoff switching valve) 1003, 1004 for shutting off the flow of the hydraulic oil in 66c. When the additional hydraulic actuator operation members (second operation members) 54f and 54g are operated by the operator and their electric signals (operation signals) are input, based on the control signals output from the controller 1, These bypass passage shutoff valves 1003, 1004 shut off the bypass passages 61b, 66c of the standard hydraulic circuit, and prevent the hydraulic oil from returning to the tank 70 through the bypass passages 61b, 66c.

As a result, the hydraulic oil can be efficiently supplied to the standard hydraulic actuators 105 to 107, 109R, 109L, 110 and the additional hydraulic actuators 1005, 1006.
Thus, operability of the additional hydraulic actuators 1005 and 1006 and the additional hydraulic actuators 1005 and 1006 is ensured.

On the other hand, if the additional hydraulic actuator operation members (second operation members) 54f and 54g are not operated by the operator and their electric signals (operation signals) are not input, the bypass passage cutoff valve 1003 , 10
04 is not activated and bypass passage 6 of the standard hydraulic circuit
1b and 66c are communicated. Here, the case where two hydraulic actuators are additionally provided is described, but the number of additional hydraulic actuators is not limited to this.

The two hydraulic actuators 100
When additional equipment is provided, the supply and discharge control valves 1001 and 10 for additional hydraulic actuators for controlling the supply and discharge of hydraulic oil to and from the additional hydraulic actuators 1005 and 1006
02 is interposed in each of the additional hydraulic actuator oil passages 1007, 1008 connected to each of the hydraulic pumps 51, 52, respectively, and hydraulic oil is supplied from either one of the hydraulic pumps 51, 52. As described above, an oil passage for an additional hydraulic actuator may be connected to one of the hydraulic pumps 51 and 52, and a plurality of supply / discharge control valves for the additional hydraulic actuator may be interposed in the oil passage for the additional hydraulic actuator. . In other words, it is not necessary to interpose one additional hydraulic actuator supply / discharge control valve in each of the additional hydraulic actuator oil passages connected to each of the hydraulic pumps 51 and 52. A plurality of supply / discharge control valves for additional hydraulic actuators may be interposed in the oil passage.

By the way, as shown in FIG. 1, in addition to the above-described configuration (the configuration for controlling the standard hydraulic actuator), the controller 1 controls the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator. Operation signal [supply / discharge control valve 1001 (1
002) proportional pressure reducing valves 1001a, 1001b (100
2a, 1002b) and a function of controlling the pump tilt angle of the hydraulic pump 51 (52) according to the operation amount of the additional hydraulic actuator operating member 54f (54g).

For this reason, as shown in FIG. 1, an electric signal from the additional hydraulic actuator operating member 54f (54g) is also inputted to the operating member signal processing means 2 of the controller 1. The operation member signal processing means 2
The additional hydraulic actuator operating member 54f (54
The processing of the electric signal from g) is performed by using the above-described standard operating hydraulic actuator operating members 54a to 54d, 54e-R, 5
Processing is performed in the same manner as the electric signal from 4e-L.

In this embodiment, as shown in FIG. 1, the operation signal from the additional hydraulic actuator operating member 54f (54g) is processed by the operating member signal processing means 2 to generate a control signal F _54f (F _54g ). And these control signals F
_{Based on 54f} (F _54g ), control of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator, control of the bypass passage cutoff valve 1003 (1004), and the hydraulic pump 51
In order to perform the pump tilt angle control of (52), the proportional pressure reducing valves 1001a, 1001b (1002a, 1002) of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator are used.
b), bypass passage cutoff valve 1003 (1004), first and second hydraulic pump tilt angle control means 3 (4) operating member corresponding tilt angle setting means 6 (11), and speed control corresponding tilt angle setting means 7 (12), each control signal F _54f (F _54g ) is output.

That is, the operating member 54f (5) for the additional hydraulic actuator processed by the operating member signal processing means 2
4g) The control signal (control amount) F of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator according to the operation amount
_54f (F _{54 g),} the operation for standard hydraulic actuators described above member 54a~54d, 54e-R, 54e- L of the operation amount in accordance with the standard hydraulic actuator supply and discharge control valves 57 to 60 (62 to 65) The first hydraulic pump tilt angle control means 3 of the controller 1
And the tilt angle setting means 6 (11) corresponding to the operating member provided in the second hydraulic pump tilt angle control means 4.

The tilt angle setting means 6 corresponding to the operation member
As shown in FIG. 5, the control signal F _54f (F _54g ) of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator according to the operation amount of the operation member 54f (54g) for the additional hydraulic actuator is also provided in (11). Taking into account, for example, the supply / discharge control valves 57 to 60 (62 to 6
5) Control amount and supply / discharge control valve 1 for additional hydraulic actuator
001 (1002) control amount], and a pump tilt angle control signal (a pump tilt angle control signal based on an operation member operation amount, a second control signal) F-1 (F-2) is set. Is output to the speed control corresponding tilt angle setting means 7 (12).

Further, the tilt angle setting means 7 corresponding to the speed control is provided.
In (12), in addition to the above-described configuration, as shown in FIG. 6, a control signal selection means 25 for additional equipment is also provided, and the control signal from the minimum signal output means 22 and the tilt angle corresponding to the operation member are provided. Second control signal F from setting means 6 (11)
-1 (F-2), and outputs it to the minimum value selection means 9 (14) as a speed-corresponding control signal F1level (F2level) for controlling the speed of the actuator. It has become. In addition, the control signal selection means 25 corresponding to additional equipment,
When operating the additional hydraulic actuators 1005 and 1006 (additional hydraulic actuator operating members 54f and 5
4g), a second control signal F for performing positive flow control.
Since it selects -1 (F-2), it is also referred to as positive control selection means (positive control switching means).

Here, control signal selecting means 2 for additional equipment
5 includes an additional hydraulic actuator operating member 54f (5
4g), an operation signal (electric signal) output when the operation is performed is input, and one of the control signals described above is selected based on the operation signal. . That is, the control signal selecting means 25 for additional equipment is provided with the additional hydraulic actuator 1005 (1006).
Is activated, that is, when the operation signal from the additional hydraulic actuator operation member 54f (54g) is input (operation signal ON), the second from the operation member corresponding tilt angle setting means 6 (11). Control signal F-1 (F-2)
Is selected and the speed-dependent control signal F1level is selected.
(F2 level) is output to the minimum value selection means 9 (14).

In this case, the control signal (first tilt angle control signal) from the tilt angle setting means 5 (10) corresponding to the bypass pressure.
F-1 (F-2) is ignored, and when the additional hydraulic actuator operation member 54f (54g) is operated, the control signal (second tilt) from the operation member corresponding tilt angle setting means 6 (11) is provided. Angle control means 7 (12) based on only the angle control signal) F-1 (F-2).
Is set, and the tilt angle control of the hydraulic pump 51 (52) is performed. Thereby, the additional hydraulic actuator 1
When the additional hydraulic actuator operating member 54f (54g) is operated to operate 005 (1006), positive flow control is performed.

In such a control, the operation members 54f (54g) for the additional hydraulic actuators are provided with the operation members 54a to 54d, 54e-R, 54e-L for the actuators as standard equipment.
In addition, even when operated independently, the operation member 54f (54g) for the additional hydraulic actuator and the operation members 54a to 54d, 54e-R, and 54e for the standard equipment actuator are provided.
The same applies when -L is operated simultaneously.
That is, the additional hydraulic actuator 1005 (1006)
Is activated, positive flow control is always performed within the allowable horsepower range.

On the other hand, additional hydraulic actuator 1005
When (1006) is not operated, that is, when the operation signal from the additional hydraulic actuator operation member 54f (54g) is not input (operation signal OFF), the control signal from the minimum signal output means 22 is selected, and This is output to the minimum value selecting means 9 (14) as a speed corresponding control signal F1level (F2level).

In this case, the operation member corresponding tilt angle setting means 6
Control signal (second tilt angle control signal) F from (11)
-1 (F-2) or the control signal (first tilt angle control signal) F-1 (F-2) from the bypass pressure corresponding tilt angle setting means 5 (10). The tilt angle setting means 7 (12) corresponding to the speed control based on the signal
Is set, and the tilt angle control of the hydraulic pump 51 (52) is performed. Thereby, the additional hydraulic actuator 1
When 005 (1006) is not operated, either positive flow control or negative flow control is performed.

Therefore, according to the control device of this construction machine, as described above, the operation in the bypass passage 61b (66c) on the downstream side of the supply / discharge control valves 57-60 (62-65) for the standard hydraulic actuators. A first control signal F- 1 (F- 1) is set based on a characteristic substantially inversely proportional to the oil flow rate.
-2) and the operating member 54 for the standard equipped hydraulic actuator
a to 54d, 54e-R, and 54e-L, a second control signal F- set based on a characteristic substantially directly proportional to the operation amount.
1 (F-2) to control the discharge flow rate of the hydraulic oil from the hydraulic pump 51 (52) by selecting one of the control signals. Further, when the additional hydraulic actuator is operated, Control amount F of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator according to the operation amount of the operation member 54f (54g) for the additional hydraulic actuator.
_The pump displacement angle control signal (second displacement angle control signal) F-1 (F-2) that also takes into account _54f (F _54g ) is selected, and the discharge flow rate of the hydraulic oil from the hydraulic pump 51 (52) is selected. Since the control (positive flow control) is performed, when the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator that controls the supply / discharge of the hydraulic oil to / from the additional hydraulic actuator 1005 (1006) is negative, Supply / discharge control valve 1001 (1002) for additional hydraulic actuator to enable flow control
Standard supply / discharge control valves for hydraulic actuators 57-60
(62-65), there is no need to install them in series, and the position of the supply / discharge control valve 1001 (1002) for the additional hydraulic actuator is increased (the flexibility is increased). There is an advantage that the control valve can be easily installed. As a result, there is an advantage that flexibility when installing a hydraulic actuator as an option is significantly improved.

Next, a first modification of the above-described embodiment will be described. In the first modification, instead of the above-described embodiment, the installation position of the bypass passage cutoff valve 1003 (1004) is set on the downstream side of the throttle 81 (82) as the bypass flow rate detecting means and the pressure sensor 74 (75). The throttle 81 (82) as these bypass flow rate detecting means
Upstream of the pressure sensor 74 (75), that is, the supply / discharge control valves 57-60 (62-6
5) and throttle 81 (82) as bypass flow rate detecting means
Between the pressure sensor 74 and the pressure sensor 74 (the position indicated by the arrow X in FIG. 2).
Is different. That is, in the first modified example, when the additional hydraulic actuator 1005 (1006) is operated, the additional hydraulic actuator 1005 (1006) is actuated based on a characteristic that is substantially directly proportional to the operation amount of the standard equipment hydraulic actuator operation members 54a to 54d, 54e-R, and 54e-L. Control signal (second
The control signal F-1 (F-2) is selected by providing a bypass passage cutoff valve 1003 (1004) in a hardware manner.

The other configuration is the same as that of the above-described embodiment, and the description thereof is omitted here. As described above, in the first modified example, the supply / discharge control valves 57 to 60 (62 to 65) for the standard equipment hydraulic actuator are provided.
In order to dispose the bypass passage cutoff valve 1003 (1004) between the hydraulic fluid actuator operating member 54f (54g) and the bypass flow rate detecting means 81, 74 (82, 75) (the position indicated by the arrow X in FIG. 2). ) Is operated, the flow of hydraulic oil into the bypass flow rate detecting means 74, 81 (75, 82) is cut off by the bypass passage cutoff valve 1003 (1004), and the bypass flow rate detecting means 74, 81
The pressure of the hydraulic oil detected by (75, 82) becomes zero (or near zero).

Here, the bypass flow rate detecting means 81 (8
When the flow rate of the hydraulic oil detected by 2) is zero (or near zero), as shown in FIG. 4, the tilt angle setting means 5 (10) corresponding to the bypass pressure makes the hydraulic circuit for the hydraulic actuator for the standard equipment hydraulic actuator. The first control signal F-1 (F-2), which is set based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage 61b (66c), is the maximum pump discharge flow rate (or the pump discharge flow rate near the maximum). ).

Then, as shown in FIG. 6, a control signal F-1 from the tilt angle setting means 5 (10) corresponding to the bypass pressure is provided.
(F-2) is a tilt angle setting means 7 (1) corresponding to speed control.
When input to the minimum signal selecting means 20 of 2), F-1
Since the relationship of <F-1 (F-2 <F-2) is satisfied, in the minimum signal selecting unit 20, each of the operating members 54a to 54d and 5 is operated by the operating member corresponding tilt angle setting unit 6 (11).
Selecting a control signal (second control signal) F-1 (F-2) set on the basis of a characteristic that is substantially directly proportional to the manipulated variables of 4e-R, 54e-L, 54f, and 54g as the control signal Fmin. [Fmin = F-1 (F−
2)]. That is, the tilt angle setting means 5 corresponding to the bypass pressure
The control signal (first control signal) F-1 from (10)
(F-2) is ignored, and the tilt angle setting means 6 corresponding to the operation member is set.
Control signal (second tilt angle control signal) F from (11)
Based on -1 (F-2), the pump tilt angle control of the hydraulic pump 51 (52) is performed (positive flow control).

For this reason, in the first modification, it is not necessary to provide the control signal selecting means 25 for additional equipment in the tilt angle setting means 7 (12) for speed control. In this case, of course, the additional hydraulic actuator operating member 5
4f (54g) and the tilt angle setting means 6 (1
There is no need to provide a signal line from 1) to the control signal selecting means 25 for additional equipment.

Therefore, according to the first modified example, the hydraulic actuators 105 to 107, 109R, 1
09L, 110, and an additional hydraulic actuator 10
05 (1006), the supply / discharge control valves 57 to 60 (62 to 6) for the hydraulic actuators provided as standard upstream of the bypass flow rate detecting means 81, 74 (82, 75).
5) and bypass flow rate detecting means 81, 74 (82, 75)
Between the additional hydraulic actuator 1005 (100
6) The bypass passage shutoff valves 1003 (1004) which are configured more compactly and are relatively easy to install are provided.
4) is added. The operating member for hydraulic actuator 54f (54
g) by simply configuring the controller 1 so that it can be operated in the same manner as that of the above-described embodiment based on the electric signal from the additional hydraulic actuator 1005 (1).
006) (including simultaneous operation with the standard hydraulic actuator), that is, when the additional hydraulic actuator operating member 54f (54g) is operated and its electric signal is input, the positive flow control is performed. Is performed, thereby increasing the degree of freedom of the arrangement position of the supply / discharge control valves 57 to 60 (62 to 65) for the additional hydraulic actuators, similarly to the above-described embodiment (flexibility). Will increase). As a result, there is an advantage that flexibility when installing a hydraulic actuator as an option is significantly improved.

Next, a second modification of the above-described embodiment will be described. The second modified example is different from the above-described embodiment in that when the bypass pressure corresponding tilt angle setting means 5 (10) receives an electric signal from the additional hydraulic actuator operating member 54f (54g), The control signal (first control signal) F-1 (F-2) to be output to the speed control corresponding tilt angle setting means 7 (12) is set to a control signal that maximizes the pump tilt angle. Is different. That is, in the second modification, the additional hydraulic actuator 10
05 (1006), the operating members 54a to 54d, 54e-R,
A control signal (second control signal) F-1 (F-F) set based on a characteristic substantially directly proportional to the operation amount of the 54e-L.
In order to select 2), the program is partially modified to respond to software. The installation positions of the bypass cutoff valves 1003 and 1004 are the same as those in the above-described embodiment [bypass flow rate detecting means 81, 74 (82,
75) on the downstream side].

Here, the tilt angle setting means 5 (10) corresponding to the bypass pressure is provided with the operating member 5 for the additional hydraulic actuator.
4f (54g) is operated and, when the electric signal is input, a control signal (first control signal) F-1 (F-F) output to the speed control corresponding tilt angle setting means 7 (12).
In order to set a control signal that maximizes the pump tilt angle as 2), instead of the output signal (detected value) from the pressure sensor 74 (75) as the bypass flow rate detecting means, the output signal is used. It is configured as having a function of setting to zero. The tilt angle setting means 5 (10) corresponding to the bypass pressure sets the output signal set to zero in this way as the output signal of the pressure sensor 74 (75) as the virtual bypass flow rate detecting means, as described above. Similarly to the embodiment (see FIG. 4), the first control signal F-1 based on a characteristic that is substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage 61b (66c) of the hydraulic circuit for the standard equipment hydraulic actuator.
(F-2) is set.

Therefore, an electric signal (operation signal) from the additional hydraulic actuator operation member 54f (54g) is input to the bypass pressure corresponding tilt angle setting means 5 (10). Here, when operating the additional hydraulic actuator 1005 (1006),
To ensure that the second control signal F-1 (F-2) from the operation member corresponding tilt angle setting means 6 (11) is selected and to simplify the control, the pressure sensor 74 is used. Instead of the output signal from (75), the output signal is set to zero, whereby the bypass pressure corresponding tilt angle setting means 5 (10) allows the bypass passage 61b (66c) of the hydraulic circuit for hydraulic actuator for standard equipment to be provided. The first control signal F-1 (F-2), which is set based on a characteristic that is substantially inversely proportional to the flow rate of the working oil in the inside, is changed to a control signal at which the maximum pump discharge flow rate (or the pump discharge flow rate close to the maximum) becomes However, the setting of the output signal from the pressure sensor 74 (75) is not limited to this, and at least the second signal from the operating member corresponding tilt angle setting means 6 (11) is set.
Of the control signal F-1 (F-2) from the first control signal F-
1 (F-2) as long as it can be made smaller,
For example, instead of the output signal from the pressure sensor 74 (75), the output signal may be set to a predetermined value near zero.

This is done for the following reason. That is, when the installation position of the bypass cutoff valve 1003 (1004) is installed at the same position as the above-described embodiment (the position downstream of the bypass flow rate detection means 81, 74 (82, 75)), the operating member for the additional hydraulic actuator is used. 54f
(54g) is operated and an electric signal is inputted, the bypass passage 61b (66c) is closed by the bypass passage cutoff valve 1003 (1004), and the detected value from the pressure sensor 74 (75) as the bypass flow rate detecting means is detected. Becomes high, and becomes substantially equal to the pump discharge pressure. If the output value from the pressure sensor 74 (75) corresponding to such a high pressure state is used as it is,
As shown in FIG. 4, the tilt angle setting means 5 corresponding to the bypass pressure is provided.
The first control signal F-1 (F-2) from (10) is a control signal (control amount) that minimizes the pump tilt angle.

Then, as shown in FIG. 6, such a first control signal F-1 (F-2) is directly input to the minimum signal selection means 20 of the speed control corresponding tilt angle setting means 7 (12). Then, F-1 <F-1 (F-2 <
F-2) holds, and the minimum signal selecting means 20 converts the first control signal F-1 (F-2) from the bypass pressure corresponding tilt angle setting means 5 (10) into the control signal Fmi.
n [Fmin = F−1 (F
-2)].

In this case, the additional hydraulic actuator 1005
Since the intended purpose of performing positive flow control when activating (1006) cannot be achieved, in the second modified example, the bypass pressure corresponding tilt angle setting means 5 (10) is When the additional hydraulic actuator operating member 54f (54g) is operated and its electric signal is input, instead of the output signal from the pressure sensor 74 (75) as the bypass flow rate detecting means,
It is configured to have a function of setting the output signal to zero (or a predetermined value near zero).

The other configuration is the same as that of the above-described embodiment, and the description thereof is omitted here. As described above, in the second modified example, the additional hydraulic actuator operation member 54f (54g) is operated, and the electric signal thereof is transmitted to the bypass pressure corresponding tilt angle setting means 5 (1).
0), the output signal from the pressure sensor 74 (75) as the bypass flow rate detecting means becomes zero (or zero) by the bypass pressure corresponding tilt angle setting means 5 (10). (A predetermined value near zero), and the output signal set to zero in this way is used as an output signal of the pressure sensor 74 (75) as a virtual bypass flow rate detecting means, as a bypass passage of a hydraulic circuit for a hydraulic actuator for standard equipment. 61b (66c), the first control signal F-1 (F
-2), the first control signal F-1
(F-2) is set as a control signal that maximizes the pump tilt angle (see FIG. 4).

Then, as shown in FIG. 6, the first control signal F from the tilt angle setting means 5 (10) corresponding to the bypass pressure is set.
When -1 (F-2) is input to the minimum signal selecting means 20 of the speed control corresponding tilt angle setting means 7 (12),
−1 <F−1 (F−2 <F−2) holds, and the minimum signal selection unit 20 sets the second control signal F set by the operation member corresponding tilt angle setting unit 6 (11).
-1 (F-2) is selected as the control signal Fmin [Fmin = F-1 (F-2)]. In other words, the first control signal F-1 (F-2) from the bypass pressure-dependent tilt angle setting means 5 (10) is ignored, and the second control signal from the operating member-dependent tilt angle setting means 6 (11) is ignored. Based on the control signal F-1 (F-2), the hydraulic pump 51 (5
The pump tilt angle control of 2) is performed (positive flow control).

For this reason, in the second modification, it is not necessary to provide the control signal selecting means 25 for additional equipment in the tilt angle setting means 7 (12) for speed control. In this case, of course, the additional hydraulic actuator operating member 5
4f (54g) and the tilt angle setting means 6 (1
There is no need to provide a signal line from 1) to the control signal selecting means 25 for additional equipment.

Therefore, according to the second modification, the hydraulic actuators 105 to 107, 109R, 1
09L, 110, and an additional hydraulic actuator 10
05 (1006), the bypass pressure corresponding tilt angle setting means 5 (10) is changed to a bypass when the additional hydraulic actuator operating member 54f (54g) is operated and its electric signal is input. Instead of the output signal from the pressure sensor 74 (75) as the flow rate detecting means, the additional hydraulic actuators 1005, 1006 are provided only by having a function of making the output signal zero (or a predetermined value near zero). Is activated (including the case of simultaneous operation with the standard hydraulic actuator), so that the positive flow control can be performed as in the above-described embodiment. Discharge control valves 57-60 (62-6
The degree of freedom of the arrangement position of 5) is increased (flexibility is increased). As a result, there is an advantage that flexibility when installing a hydraulic actuator as an option is significantly improved.

In the above-described embodiment, the description has been made assuming that the standard-equipped hydraulic actuator and the additional hydraulic actuator are provided in advance. Includes the case where additional equipment is installed.

[0199]

As described above in detail, according to the control apparatus for a construction machine according to the first aspect of the present invention, the control apparatus is set based on the characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage. One of the first control signal and the second control signal set based on the characteristic substantially directly proportional to the operation amount of the operation member is selected to control the discharge flow rate of the hydraulic oil from the hydraulic pump. Further, when the second hydraulic actuator is operated, the second control signal is selected to control the discharge flow rate of the hydraulic oil from the hydraulic pump. When the second hydraulic actuator is additionally provided, the second control valve for controlling the supply of the hydraulic oil to the second hydraulic actuator is disposed in substantially inverse proportion to the flow rate of the hydraulic oil in the bypass passage. To the characteristics Therefore, it is not necessary to install the second control valve in series with the first control valve so that the pump flow rate can be controlled, so that the degree of freedom in the arrangement position of the second control valve increases (the flexibility increases). Therefore, there is an advantage that the second control valve can be easily installed.

According to the control device for a construction machine according to the present invention, when the second hydraulic actuator is operated, the bypass passage is shut off by the bypass passage shutoff valve. Is not returned, whereby the hydraulic oil can be efficiently supplied to the first hydraulic actuator and the second hydraulic actuator, and there is an advantage that the operability of the first and second hydraulic actuators can be secured.

According to the control device for a construction machine according to the third aspect of the present invention, when the second hydraulic actuator is operated, the bypass passage is shut off by the bypass passage shut-off valve, whereby the second passage is shut off. Since the control signal is selected to control the discharge flow rate of the hydraulic oil from the hydraulic pump, for example, when an optional second hydraulic actuator is additionally provided, the second hydraulic actuator is used. The degree of freedom of the arrangement position of the second control valve for controlling the supply of the hydraulic oil to the oil increases (the flexibility increases),
There is an advantage that the second control valve can be easily installed.

According to the control device for a construction machine of the present invention, when the second hydraulic actuator is operated, the detection value detected by the bypass flow rate detection means is set to zero to thereby reduce the second hydraulic actuator. Since the control signal is selected to control the discharge flow rate of the hydraulic oil from the hydraulic pump, for example, when an optional second hydraulic actuator is additionally provided, the second hydraulic actuator is used. Since the degree of freedom in the arrangement position of the second control valve for controlling the supply of hydraulic oil to the control valve increases (the flexibility increases), there is an advantage that the second control valve can be easily installed.

[Brief description of the drawings]

FIG. 1 is a control block diagram for explaining pump tilt angle control in a control device for a construction machine according to an embodiment of the present invention.

FIG. 2 is an overall configuration diagram of a control device for a construction machine according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining a control valve of the control device for the construction machine according to the embodiment of the present invention.

FIG. 4 is a block diagram for explaining a bypass pressure corresponding tilt angle setting means in the control device for the construction machine according to the embodiment of the present invention.

FIG. 5 is a block diagram for explaining an operation member corresponding tilt angle setting means in the control device for the construction machine according to the embodiment of the present invention.

FIG. 6 is a block diagram for explaining a tilt angle setting unit corresponding to speed control in the control device for a construction machine according to one embodiment of the present invention.

FIG. 7 shows the relationship between the load W and the working machine speed (pump tilt angle) when performing the pump tilt angle control by the speed control-compatible tilt angle setting means in the control device for the construction machine according to the embodiment of the present invention. 7A and 7B are diagrams showing the relationship, wherein FIG. 7A shows a case where the pump tilt angle control is performed based on a characteristic inversely proportional to the bypass flow rate, and FIG. When performing control, (c)
When pump tilt angle control is performed by selectively using a characteristic inversely proportional to the bypass flow rate and a characteristic proportional to the operation member operation amount, (d) is based on a required tilt angle smaller than a predetermined value. The case where the pump tilt angle control is performed is shown.

FIG. 8 is a block diagram for explaining an allowable horsepower corresponding tilt angle setting means in the control device for the construction machine according to the embodiment of the present invention.

FIG. 9 is a schematic perspective view showing a general construction machine.

FIG. 10 is an overall configuration diagram of a conventional construction machine control device.

FIG. 11 is a schematic diagram for explaining pump tilt angle control in a conventional construction machine control device.

12A and 12B are diagrams for explaining pump tilt angle control in a conventional construction machine control device, wherein FIG. 12A is a diagram illustrating a relationship between an operation member operation amount and a control valve movement amount, and FIG. Is a diagram showing the relationship between the control valve movement amount and the control valve opening area, (c)
FIG. 4 is a diagram showing a relationship between a bypass oil passage opening area and a bypass flow rate, FIG. 4D is a diagram showing a relationship between a bypass flow rate and an output signal of a bypass pressure detecting means, and FIG. The figure which shows the relationship with a flow rate (pump tilt angle) is each shown.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Controller (control means) 2 Operating member signal processing means 3 First hydraulic pump tilt angle control means 4 Second hydraulic pump tilt angle control means 5, 10 Bypass pressure corresponding tilt angle setting means 6, 11 Tilt corresponding to operating member Shift angle setting means 7,12 Speed control compatible tilt angle setting means 8,13 Allowable horsepower compatible tilt angle setting means 8A Allowable horsepower storage section 8B Allowable horsepower compatible tilt angle calculation section 9,14 Minimum value selecting means 20 Minimum signal Selection means 21 required displacement angle comparison means 22 minimum signal output means 23 predetermined value setting means 24 required displacement angle output means 25 additional equipment corresponding control signal selection means 51 first hydraulic pump 52 second hydraulic pump 54a-54d, 54e- R, 54e-L Operating member (operating member for standard equipped hydraulic actuator, first operating member) 54f, 54g Operating member (additional hydraulic actuator) Operating member, second operating member) 57-60, 62-65 Control valve (first control valve, supply / discharge control valve for standard equipped hydraulic actuator) 61,66 Oil passage (standard equipped hydraulic actuator oil passage, (1) Hydraulic oil supply passage 61b, 66c Bypass passage 71 Engine speed sensor 72, 73 Pressure sensor 74, 75 Pressure sensor (bypass pressure detecting means, bypass flow rate detecting means) 81, 82 Throttle (bypass pressure detecting means, bypass flow rate) Detection means) 105 to 107, 109R, 109L, 110 Hydraulic actuator (standard equipped hydraulic actuator, first hydraulic actuator) 1001, 1002 Control valve (second control valve, supply / discharge control valve for additional hydraulic actuator) 1003, 1004 Bypass passage shutoff valve 1005, 1006 Hydraulic actuator (additional oil Actuator, a second hydraulic actuator) 1007, 1008 oil passage (oil passage for additional hydraulic actuator, a second hydraulic fluid supply passage))

Claims (4)

[Claims] An operating member that is operated by an operator to output an electric signal; a hydraulic pump that discharges hydraulic oil in a tank; and a hydraulic oil that is discharged from the hydraulic pump is supplied through a first hydraulic oil supply passage. A first hydraulic actuator that is driven by the first hydraulic actuator; a first control valve that is interposed in the first hydraulic oil supply passage and controls supply of hydraulic oil to the first hydraulic actuator; A bypass passage for returning hydraulic oil not supplied to the first hydraulic actuator via the first control valve to the tank; and a hydraulic oil discharged from the hydraulic pump separately from the first hydraulic oil supply passage. A second hydraulic actuator driven by being supplied through a second hydraulic oil supply passage provided, and a second hydraulic actuator interposed in the second hydraulic oil supply passage, for supplying hydraulic oil to the second hydraulic actuator. A second control valve for controlling the supply, a first control signal set based on a characteristic substantially inversely proportional to the flow rate of the hydraulic oil in the bypass passage, and a characteristic substantially proportional to the operation amount of the operation member. Control means for selecting one of the second control signals set based on the control signal to control the discharge flow rate of the hydraulic oil from the hydraulic pump, wherein the control means includes: When an electric signal is input from an operation member for operating the second hydraulic actuator, the second control signal is selected to control a discharge flow rate of hydraulic oil from the hydraulic pump. A control device for a construction machine. A bypass passage shutoff valve for shutting off a flow of hydraulic oil returned to the tank through the bypass passage, wherein the control means operates the second hydraulic actuator of the operation member. The control device for a construction machine according to claim 1, wherein the bypass passage shutoff valve is controlled so that the bypass passage is shut off when an electric signal is input from a member. 3. A bypass flow rate detecting means disposed in the bypass passage downstream of the first control valve for detecting a flow rate of hydraulic oil in the bypass passage; A bypass passage shutoff valve disposed in the bypass passage for shutting off a flow of hydraulic oil returned to the tank through the bypass passage, wherein the control means comprises: the first control signal and the second control signal. A control signal for reducing the pump flow rate is selected to control the discharge flow rate of hydraulic oil from the hydraulic pump, and an electric signal from an operation member for operating the second hydraulic actuator among the operation members 2. The control device for a construction machine according to claim 1, wherein the control unit controls the bypass passage shutoff valve so that the bypass passage is shut off when the control signal is input. 4. A bypass flow rate detecting means disposed in the bypass passage downstream of the first control valve for detecting a flow rate of hydraulic oil in the bypass passage, wherein the control means comprises: And controlling the discharge flow rate of hydraulic oil from the hydraulic pump by selecting a control signal for reducing the pump flow rate from the control signal and the second control signal. 2. The control of a construction machine according to claim 1, wherein when an electric signal is input from an operating member for operating the hydraulic actuator, a detection value detected by the bypass flow rate detection unit is set to zero. apparatus.