JP2000309948A - Control apparatus for construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus for construction machinery, which suppresses loss of an engine output by controlling the flow rate of a pump so as not to excessively increase pump delivery pressure at the time of leveling work, to thereby prevent lowering of fuel economy. SOLUTION: The control apparatus for construction machinery comprises hydraulic pumps 51, 52, a plurality of operating members 54, and a control means 1 for controlling flow rates of discharge from the hydraulic pumps 51, 52. The control means 1 includes a boom fine operation determining means 2 for determining whether or not a boom fine operation is carried out based on a manipulated variable of a boom operating member 54a, a stick fine operation-determining means 3 for determining whether or not a stick minute operation is carried out based on a manipulated variable of a stick operating member 54b, a bucket minute operation determining means 4 for determining whether or not a bucket fine operation is carried out based on a manipulated variable of a bucket operating member 54c, and a pump inclining/rotating angle control means 5 for controlling inclining/rotating angles of the hydraulic pumps 51, 52, based on results of the determination of the boom fine operation-determining means 2, the stick fine operation determining means 3, and the bucket fine operation determining means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump provided in a construction machine, which controls a tilt angle of a hydraulic pump, thereby controlling a pump discharge flow rate to control the operation of a hydraulic actuator such as a boom cylinder or a bucket cylinder. The present invention relates to a control device for a construction machine.

[0002]

2. Description of the Related Art Generally, construction machines such as hydraulic excavators are
As shown in FIG. 8, the upper revolving unit 102 and the lower traveling unit 10
0 and a working device 118. Undercarriage 10
0 has a right track 100R and a left track 100L that can be driven independently of each other, while the upper swing body 102 is provided so as to be able to swing in a horizontal plane with respect to the lower running body 100.

[0003] The working device 118 mainly includes a boom 10.
3, a stick 104, a bucket 108, and the like. 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 driving hydraulic cylinder (boom cylinder, hydraulic actuator) 1 for driving the boom 103 is provided between the upper swing body 102 and the boom 103.
05 is provided, and between the boom 103 and the stick 104, a stick driving hydraulic cylinder (stick cylinder,
A hydraulic actuator 106 is provided. Also,
A bucket driving hydraulic cylinder (bucket cylinder, hydraulic actuator) 107 for driving the bucket 108 is provided between the stick 104 and the bucket 108.

Each of the cylinders 105 to 107 has a plurality of control valves such as 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. A hydraulic circuit (not shown) is connected to the hydraulic pump, and hydraulic fluid of a predetermined hydraulic pressure is supplied from each hydraulic valve via each control valve, and the hydraulic pump is driven according to the supplied hydraulic pressure. It has become.

Here, a plurality of control valves are provided with hydraulic oil supply passages (hydraulic pump-cylinder passage, PC) for supplying and discharging hydraulic oil to and from each of the cylinders 105 to 107 and the hydraulic pump.
Passage) and a CT throttle interposed in the hydraulic oil discharge passage (cylinder-tank passage, CT passage), and a bypass passage leading from the hydraulic pump to the reservoir tank. It also has an interposed bypass passage restrictor.

With such a configuration, the boom 103 moves in the directions of arrows a and b in the figure, the stick 104 moves in the directions of arrows c and d in the figure, and the bucket 108 moves in the directions of arrows e and f in the figure. It is configured to be rotatable. The rotation of the boom 103 in the direction of the arrow a in the figure is called boom up, and the rotation in the direction of the arrow b in the figure is called boom down. The rotation of the stick 104 in the direction of the arrow c in the figure is called stick-out, and the rotation of the stick 104 in the direction of the arrow d in the figure is called stick-in. The bucket 108
Rotation in the direction of arrow e in the figure is called bucket open,
Rotation in the direction of arrow f in the figure is called bucket-in.

The driving operation room 101 includes left lever, right lever, and left pedal as operation members for controlling the operation (running, turning, boom turning, stick turning, and bucket turning) of the hydraulic excavator. And a right pedal and the like. Then, for example, when the operator operates these operating members such as levers and pedals, each control valve of the hydraulic circuit is controlled, and each of the cylinders 105 to 107 is driven.
4 and the bucket 108 can be rotated.

A pilot hydraulic circuit is provided to control each control valve. Thereby, boom 1
To operate the 03 and the stick 104, the boom operating member and the stick operating member in the driving operation room 101 are operated, and the pilot hydraulic pressure is applied to the boom control valve and the stick control valve through the pilot oil passage. Then, the control valve for the boom and the control valve for the stick are driven to required positions. Thus, the supply and discharge of hydraulic oil to and from the hydraulic cylinder 105 for driving the boom and the hydraulic cylinder 106 for driving the stick are adjusted, and these cylinders 105 and 106 are driven to expand and contract to required lengths.

As described above, in the hydraulic excavator, the cylinders 105 to 107 are driven to expand and contract and the work devices 118 such as the boom 103, the stick 104, and the bucket 108 are driven to perform various operations such as excavation. It has become. By the way, as one operation in such various operations, for example, there is a so-called leveling operation (leveling operation). In this leveling operation,
The above-described boom-up, stick-in, and bucket-in operations are performed simultaneously.

When the boom-up operation is performed, the boom 103 is driven as follows. That is, when the boom-up operation is performed, the boom 103 can be raised by extending the boom drive hydraulic cylinder 105. In this case, the pilot oil pressure is made to act on the boom control valve through the pilot oil passage. Thereby, the spool position of the boom control valve becomes the boom raising position, and hydraulic oil from the hydraulic pump is supplied to one chamber of the boom driving hydraulic cylinder 105 through the oil passage. On the other hand, hydraulic oil in the other room of the boom drive hydraulic cylinder 105 is discharged to the tank through the oil passage. This allows
While the boom drive hydraulic cylinder 105 extends, the boom 103 is rotated upward as shown by an arrow a in FIG.

When the stick-in operation is performed, the stick 104 is driven as follows. That is, when the stick-in operation is performed, the stick drive hydraulic cylinder 106 may be extended to lower the stick 104. In this case, the pilot oil pressure is made to act on the stick control valve through the pilot oil passage. Thereby, the spool position of the stick control valve becomes the stick lowered position, and the operating oil from the hydraulic pump is supplied to one chamber of the stick driving hydraulic cylinder 106 through the oil passage. On the other hand, hydraulic oil in the other chamber of the stick driving hydraulic cylinder 106 is discharged to the tank through the oil passage. As a result, the stick driving hydraulic cylinder 106 extends while the stick 10
4 is rotated downward as shown by arrow d in FIG.

Further, when the bucket-in operation is performed, the bucket 108 is driven as follows. That is,
When the bucket-in operation is performed, the bucket 108
Can be closed by extending the bucket driving hydraulic cylinder 107. In this case, the pilot oil pressure is made to act on the bucket control valve through the pilot oil passage. As a result, the spool position of the bucket control valve becomes the bucket closed position, and hydraulic oil from the hydraulic pump is supplied to one chamber of the bucket driving hydraulic cylinder 107 through the oil passage. On the other hand, hydraulic oil in the other chamber of the bucket driving hydraulic cylinder 107 is discharged to the tank through the oil passage.
This causes the bucket 108 to move in the closing direction as shown by the arrow f in FIG. 8 while the bucket driving hydraulic cylinder 107 extends.

In order to ensure the simultaneous operation of the boom 103, the stick 104 and the bucket 108, the pressure of the hydraulic oil discharged from the hydraulic pump is equal to the maximum pressure among the working pressures of these working machines ( (Maximum pressure value). As a technique for securing the pressure of the hydraulic oil, the pump discharge flow rate is slightly increased from the total flow rate of the hydraulic oil supplied to each cylinder, and the excess pump discharge flow rate is reduced by the bypass passage restriction of the control valve to increase the pressure. It is common.

[0014]

However, as described above, the boom 103, the stick 104, and the bucket 108
There is, for example, a leveling operation as an operation for simultaneously operating the, and the leveling operation is performed by a fine operation for each of boom-up, stick-in, and bucket-in. Also, in this case, the load direction of the stick-in and the bucket-in is the direction of falling of the linkage's own weight, so that in these operations, the flow rate of the hydraulic oil discharged from the hydraulic pump is not so necessary, and the pressure of the hydraulic oil is not so large. Not necessary.

In such a leveling operation, in the other operation in which any one of the boom 103, the stick 104, and the bucket 108 is operated without fine operation, the same amount of the operating oil as the flow rate of the operating oil discharged from the hydraulic pump is used. Is supplied, hydraulic fluid of an excessive flow rate is supplied by that amount, and the pump discharge pressure from the hydraulic pump is also excessively increased.

As described above, since the pump flow rate of the hydraulic pump is controlled so that the pump discharge pressure becomes excessive, the output of the engine for driving the hydraulic pump is correspondingly reduced, which leads to deterioration of fuel efficiency. Will be.
The present invention has been made in view of such a problem, and performs pump flow control so that a pump discharge pressure does not excessively increase when a boom, a stick, or a bucket is finely operated during a so-called leveling operation. Accordingly, an object of the present invention is to provide a control device for a construction machine capable of suppressing a loss in engine output and preventing deterioration of fuel efficiency.

[0017]

According to a first aspect of the present invention, there is provided a control apparatus for a construction machine, comprising: a hydraulic pump for discharging hydraulic oil in a tank; a plurality of operating members operated by an operator; Control means for controlling a discharge flow rate from the hydraulic pump, wherein the control means determines whether a boom fine operation has been performed based on an operation amount of a boom operation member among the plurality of operation members. Boom fine operation determining means, stick fine operation determining means for determining whether a stick fine operation has been performed based on the operation amount of the stick operating member of the plurality of operating members, Bucket fine operation determining means for determining whether bucket fine operation has been performed based on the operation amount of the bucket operating member, the boom fine operation determining means, and the stick fine operation determining means. And it is characterized in that based on the determination result of the bucket fine operation determination means and a pump tilting angle control means for tilting angle control of the hydraulic pump.

According to a second aspect of the present invention, there is provided a construction machine control device according to the first aspect, wherein the plurality of operation members output an electric signal in accordance with an operation amount. The control means performs tilt angle control of the hydraulic pump based on electric signals from the plurality of operating members. According to a third aspect of the present invention, there is provided a construction machine control device according to the first aspect, wherein the boom fine operation determining means determines whether or not a boom up fine operation is performed, and The operation determining means is configured to determine whether a stick-in fine operation has been performed, and the bucket fine operation determining means includes:
The pump tilt angle control means is configured to determine whether a bucket-in fine operation has been performed. The boom-up fine operation is performed by the boom fine operation determination means, the stick fine operation determination means, and the bucket fine operation determination means. When it is determined that the stick-in fine operation and the bucket-in fine operation have been performed, the tilt angle control of the hydraulic pump is performed in accordance with electric signals from the boom operating member, the stick operating member, and the bucket operating member. It is characterized by performing.

According to a fourth aspect of the present invention, there is provided a construction machine control device according to the first aspect, wherein the boom fine operation determining means determines whether a boom up fine operation has been performed. The stick fine operation determining means is configured to determine whether a stick-in fine operation has been performed, and the bucket operation determining means is configured to determine whether a bucket-in operation has been performed. The angle control means determines whether the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation have been performed by the boom fine operation determination means, the stick fine operation determination means, and the bucket fine operation determination means. The discharge flow rate from the hydraulic pump is reduced from the discharge flow rate from the hydraulic pump when any of the fine operations is not a fine operation. And characterized by performing the tilting angle control of the hydraulic pump to Suyo.

[0020]

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. 8), and includes the upper swing body 102, the lower traveling body 100, and the working device 118. I have.

The undercarriage 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 device 118 mainly includes the boom 103, the stick 104, the bucket 108, and the like.
Numeral 3 is pivotably attached to the upper swing body 102. Also, a stick 104 is connected to the tip of the boom 103 so as to be rotatable in a vertical plane.

A boom driving hydraulic cylinder (boom cylinder, hydraulic actuator) for driving the boom 103 is provided between the upper swing body 102 and the boom 103.
A stick drive hydraulic cylinder (stick cylinder, hydraulic actuator) 106 for driving the stick 104 is provided between the boom 103 and the stick 104. A bucket driving hydraulic cylinder (bucket cylinder, hydraulic actuator) 107 for driving the bucket 108 is provided between the stick 104 and the bucket 108.
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 relative 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 a plurality (two in this case) of hydraulic pumps 51, which are driven by an engine (mainly a diesel engine) 50, as described later. 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 supplied hydraulic pressure.

Here, the hydraulic pumps 51 and 52 discharge hydraulic oil in the reservoir tank 70 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). 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 against 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 operation member 54 by the operator can be taken into consideration in addition to the pressure of the hydraulic oil in the oil passage that constitutes the hydraulic circuit, the pressure of the hydraulic oil in the oil passage 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 the operator by switching an engine speed setting dial. Here, a maximum engine speed (for example, about 2000 rpm) and a 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 the hydraulic pumps 51 and 52 and a pilot pump 83 described later.

The cylinders 105 to 107 are also supplied from a plurality (two in this case) of 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 working 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.

When the operator operates these operating members 54, the control valves 57 to 60 and 62 to 65 interposed in the hydraulic circuit 53 are controlled to control the cylinders 105 to 107 and the hydraulic motor. 109L, 109
R, 110 is driven. Thereby, the upper swing 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 member operated when rotating the boom 103 is referred to as a boom operating member 54a, and the member operated when rotating the stick 104 is referred to as a stick operating member 54b. What is operated in this case is called a bucket operating member 54c. Next, a hydraulic circuit 53 for controlling each of these cylinders will be described.

As shown in FIG. 2, the hydraulic circuit 53
A circuit section 55 and a second circuit section 56 are provided. this house,
The first circuit unit 55 includes an oil passage 61 connected to the first hydraulic pump 51, a right travel motor control valve 57, a bucket control valve 58, and a first boom control valve 5 interposed in the oil passage 61.
9, and a control valve such as the second stick control valve 60.

Then, the hydraulic oil from the first hydraulic pump 51 is supplied to the right traveling motor 109R through 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.

A throttle (a throttle with a relief valve) 81 is provided on the downstream side of the oil passage 61 of the first circuit portion 55, and hydraulic oil from the first hydraulic pump 51 is supplied to the reservoir tank 70 through the throttle 81. To return to The second circuit portion 56 includes an oil passage 66 connected to the second hydraulic pump 52, and a left traveling motor control valve 6 interposed in the oil passage 66.
2, control valves such as a control valve 63 for a swing motor, a control valve 64 for a first stick, a control valve 65 for a second boom, and a throttle 82
And is provided.

Then, the hydraulic 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. It has become. Also, the second
Hydraulic oil from the hydraulic pump 52 is supplied to the turning motor 110 via the oil passage 66 and the turning motor control valve 63, whereby the turning motor 110 is driven. Further, the hydraulic oil from the second hydraulic pump 52 is supplied to the stick driving hydraulic cylinder 106 via the oil passage 66 and the first stick control valve 64, and the oil passage 66 and the second boom control valve 65. , And is supplied to the boom driving hydraulic cylinder 105, whereby the respective cylinders 105 and 106 are driven.

A throttle (throttle with a relief valve) 82 is provided on the downstream side of the oil passage 66 of the second circuit portion 56, and through this throttle 82, hydraulic oil from the second hydraulic pump 52 is supplied to the reservoir tank 70. To return to The control valves 57 to 60 and 62 to 65 are housed in a control unit (not shown).

As described above, in the present embodiment, the stick 104 important for the operation of the construction machine is attached to the other working machine 11.
In addition to the hydraulic oil from the second hydraulic pump 52 of the second circuit portion 56, the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 Hydraulic oil 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 control valve 64 for the first stick is controlled by the proportional control valves 64a and 64b, and the control valve 60 for the second stick 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 at the time of simultaneous operation with another working 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 the present embodiment, the oil passage 6 for supplying and discharging the hydraulic oil to and from the hydraulic cylinder 106 for driving the stick is provided.
A regeneration valve 76 for 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 the 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 (here, five) of 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 8 interposed in oil passages (hydraulic 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 first hydraulic pump 51, the second hydraulic pump 52, and the reservoir tank 70 communicate with the CT throttle 9 interposed in oil passages (hydraulic oil discharge passages, CT passages) 66b and 69 that communicate with the first hydraulic pump 51 and the second hydraulic pump 52. Passage restrictor 1 interposed in oil passages (bypass passages) 61b, 66c
0.

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.
Bypass passage throttle 10 for stick control valves 60 and 64
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 8 of FIG. 4 is interposed in the PC passages 61a and 66a, and the CT of the stick control valves 60 and 64 is controlled.
By interposing the throttle 9 in the CT passages 66b and 69,
The stick control valves 60 and 64 can be in the stick raising position.

In setting the diameters of the apertures 8, 9, and 10, the working device 1 such as the boom 103 or the stick 104 is used.
In order to ensure the interlocking of the operation members 18, it is considered that all the working devices 118 move when each operation member 54 is fully operated. 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 (the opening area of the working oil discharge passage, the 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 9. You. The first hydraulic pump 51, the second hydraulic pump 5
Oil passages 61b, 66 communicating the reservoir 2 and the reservoir tank 70.
The opening area of c (the opening area of the bypass passage) is adjusted.

In this embodiment, as shown in FIG. 2, the pilot pump 83 and the proportional pressure reducing valves 57a-60 are controlled to control the control valves 57-60 and 62-65.
a, 57b-60b, 62a-65a, 62b-65b
And a pilot hydraulic circuit including: 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 an operation signal 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, the boom 10
3 is operated by operating the boom operating member 54a in the operation room 101 to cause the pilot oil pressure P from the pilot pump 83 to act on the boom control valves 59 and 65 through a pilot oil passage (not shown). The boom control valves 59 and 65 are moved to required positions. Thereby, the supply and discharge of the hydraulic oil of the boom drive hydraulic cylinder 105 is adjusted, and these cylinders 105 are driven to expand and contract to a required length, whereby the boom 103 is operated.

For example, to rotate the boom 103 downward (boom down), the boom drive hydraulic cylinder 10
5 may be contracted. In this case, the pilot oil pressure is applied to the first boom control valve 59 through the pilot oil passage. As a result, the spool position of the first boom control valve 59 becomes the boom lower rotation position (boom down position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 flows through the oil passages 95 and 79. , And is supplied to one chamber of the boom drive hydraulic cylinder 105 and supplied to one chamber of the boom drive hydraulic cylinder 105. On the other hand, the hydraulic oil in the other chamber of the boom drive hydraulic cylinder 105 is supplied to the oil passages 78 and 6.
After that, it is discharged to the reservoir tank 70. Thereby, while the boom drive hydraulic cylinder 105 contracts,
The boom 103 is rotated downward as shown by the arrow b in FIG.

Conversely, to rotate the boom 103 upward (boom up), the boom drive hydraulic cylinder 10
5 may be extended. In this case, the pilot oil pressure is caused to act on the first boom control valve 59 and the second boom control valve 65 through the pilot oil passage. Thereby, the first
The spool positions of the boom control valve 59 and the second boom control valve 65 become the boom upper rotation position (boom up position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 is supplied to the oil passage 95. , 78, and is supplied to one chamber of the boom driving hydraulic cylinder 105, and the hydraulic oil from the second hydraulic pump 52 of the second circuit portion 56 is supplied to the oil passages 66a, 90, 7
After that, the boom drive hydraulic cylinder 105 is supplied to another chamber. On the other hand, the boom drive hydraulic cylinder 10
The hydraulic oil in one room of the fifth oil passage 79, 91, 66b or
The oil is discharged to the reservoir tank 70 through the oil passages 79 and 69. As a result, the boom 103 is rotated upward as indicated by an arrow a in FIG. 8 while the boom drive hydraulic cylinder 105 is extended.

Further, the boom drive hydraulic cylinder 105
In order to maintain the current state, the pilot hydraulic pressure is applied to the first boom control valve 59 and the second boom control valve 65 as appropriate, and the first boom control valve 59 and the second boom control valve 65 are controlled.
Set the position of each spool to the neutral position (hydraulic supply / discharge path cutoff position)
What should I do? Thus, the supply and discharge of hydraulic oil in each oil chamber of the boom drive hydraulic cylinder 105 is stopped, and the boom 103 is held at the current position.

In order to operate the stick 104, for example, the operating member 54 in the operation room 101 is operated, and the pilot oil pressure P from the pilot pump 83 is passed through a pilot oil passage (not shown) to control the stick control valve 60, 64 to control the stick control valves 60, 6
4 is driven to a required position. This allows
The supply and discharge of the hydraulic oil for the stick driving hydraulic cylinder 106 is adjusted, and these cylinders 105 and 106 are driven to expand and contract to a required length, whereby the stick 104 is operated.

For example, to rotate the stick 104 inward (stick-in), the stick driving hydraulic cylinder 106 may be extended. In this case, the pilot oil pressure is applied to the second stick control valve 60 through the pilot oil passage. As a result, the spool position of the second stick control valve 60 becomes the stick inner rotation position (stick-in position), and the operating oil from the first hydraulic pump 51 of the first circuit portion 55 flows through the oil passages 61 and 67. After that, it is supplied to one chamber of the stick driving hydraulic cylinder 106. On the other hand, the stick driving hydraulic cylinder 1
06, the hydraulic oil in the other chamber is discharged to the reservoir tank 70 via the oil passages 68, 69. As a result, while the stick driving hydraulic cylinder 106 extends, the stick 1
04 is rotated inward as indicated by arrow d in FIG.

Conversely, to rotate the stick 104 outward (stick out), the stick driving hydraulic cylinder 106 may be contracted. In this case, the pilot oil pressure is applied to the second stick control valve 60 through the pilot oil passage. As a result, the spool position of the second stick control valve 60 becomes the stick outside rotation position (stick out position), and the hydraulic oil from the first hydraulic pump 51 of the first circuit portion 55 flows through the oil passages 61 and 68. After that, it is supplied to another chamber of the stick driving hydraulic cylinder 106. On the other hand, the stick driving hydraulic cylinder 1
Hydraulic oil in one room of 06 is discharged to the reservoir tank 70 through the oil passages 67 and 69. As a result, while the stick driving hydraulic cylinder 106 contracts, the stick 1
04 is rotated outward as shown by arrow c in FIG.

Further, the stick driving hydraulic cylinder 1
In order to maintain the current state of 06, the pilot oil pressure is applied to the second stick control valve 60 as appropriate, and the position of each spool of the second stick control valve 60 is set to the neutral position (the hydraulic supply / discharge path shutoff position). do it. Thus, the supply and discharge of hydraulic oil in each oil chamber of the stick driving hydraulic cylinder 106 is stopped, and the stick 104 is held at the current position.

In order to operate the bucket 108, for example, the bucket operating member 54c in the operation room 101 is operated.
, The pilot oil pressure P from the pilot pump 83 is applied to the bucket control valve 58 through a pilot oil passage (not shown) to move the bucket control valve 58 to a required position. Thereby, the supply and discharge of the hydraulic oil of the bucket driving hydraulic cylinder 107 is adjusted, and these cylinders 107 are driven to expand and contract to a required length.
The bucket 108 is operated.

For example, to rotate the bucket 108 inward (bucket-in), the bucket driving hydraulic cylinder 107 may be extended. In this case, the pilot hydraulic pressure is applied to the bucket control valve 58 through the pilot oil passage. Thereby, the spool position of the bucket control valve 58 is shifted to the bucket inner rotation position (bucket-in position).
Thus, the hydraulic oil from the first hydraulic pump 51 of the first circuit section 55 is supplied to one chamber of the bucket driving hydraulic cylinder 107 through the oil passages 61 and 92. On the other hand, hydraulic oil in the other chamber of the bucket driving hydraulic cylinder 107 is discharged to the reservoir tank 70 through the oil passages 93 and 69. As a result, the bucket driving hydraulic cylinder 107 is extended, and the bucket 108 is rotated inward as shown by an arrow f in FIG.

Conversely, to rotate the bucket 108 outward (bucket open), the bucket driving hydraulic cylinder 107 may be contracted. In this case, the pilot oil pressure is supplied to the bucket control valve 58 through the pilot oil passage.
To act on. As a result, the spool position of the bucket control valve 58 becomes the bucket outside rotation position (bucket open position), and the first hydraulic pump 51 of the first circuit portion 55
Is supplied to another chamber of the bucket driving hydraulic cylinder 107 through the oil passages 94 and 93. On the other hand,
The hydraulic oil in one chamber of the bucket driving hydraulic cylinder 107 is discharged to the reservoir tank 70 through the oil passages 92 and 69. Thereby, the bucket driving hydraulic cylinder 107
While contracting, the bucket 108 is rotated outward as shown by an arrow e in FIG.

Further, the bucket driving hydraulic cylinder 10
7, the pilot hydraulic pressure is applied to the bucket control valve 58 as appropriate to control the bucket control valve 58.
May be set to the neutral position (the hydraulic supply / discharge path shutoff position). Thereby, the supply and discharge of the hydraulic oil in the oil chamber of the bucket driving hydraulic cylinder 107 is stopped, and the bucket 108 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 operator with the engine speed setting dial.

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 portions 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.

A pressure sensor (P / P) is provided downstream of each of the control valves 57 to 60 of the oil passage 61 of the first circuit portion 55 and each of the control valves 62 to 65 of the oil passage 66 of the second circuit portion 56. S
-N1) 74 and a pressure sensor (P / S-N2) 75, and detection signals from these pressure sensors 74 and 75 are sent to the 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 driving.
BMd) 80 is provided, and 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 this embodiment, a 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 hydraulic pump 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, position control of each of the regeneration valves 76 and 77, and the like.

The tilt angle control of the first hydraulic pump 51 and the second hydraulic pump 52 by the controller 1
Negative flow control is performed based on detection signals from respective pressure sensors 74 and 75 provided on the downstream side of the bypass passage 61b of the circuit portion 55 and on the downstream side of the bypass passage 66c of the second circuit portion 56. ing. Since the negative flow control is performed based on the pressure detected by the pressure sensors 74 and 75, the pressure detected by the pressure sensors 74 and 75 is also referred to as a negative control pressure.

Here, the negative flow control (electronic negative flow control system)
This means a pump flow rate control having a negative characteristic such that the pump discharge flow rate is reduced when the pressure on the downstream side of the bypass passages 61b and 66c increases. Here, the negative flow control is performed by controlling the operation amount of each operation member 54, that is, the flow rate control in which the pump discharge flow rate is controlled according to the negative control pressure, and the load pressure applied to the actuator, that is, the pump discharge flow rate in accordance with the pump discharge pressure. Controlled horsepower control is divided into.

Among them, the flow rate control can control the speed of the actuator (each cylinder) within the allowable horsepower. That is, the pump discharge flow rate can be controlled in accordance with the operation amount of each operation member 54, that is, the negative control pressure.
The speed of the actuator can be controlled. By the way, when each operation member 54 is fully operated and the pump discharge flow rate is maximum and the actuator speed is maximum, the pump discharge flow rate (that is, the actuator speed) is determined by the following equation.

Pump discharge flow rate Q = allowable horsepower W / pump discharge pressure P In this state, if the load pressure applied to the actuator changes, the pump discharge pressure P also changes, and the pump discharge flow rate Q also changes according to the above equation. Therefore, this also causes the speed of the actuator to fluctuate. As described above, the pump discharge flow rate Q is not controlled according to the operation amount of each operation member 54, but is controlled according to the load pressure applied to the actuator, that is, the pump discharge pressure P. Is called horsepower control in a state where the control depends on the allowable horsepower W of the engine 50 that drives the first hydraulic pump 51 and the second hydraulic pump 52.

When such horsepower control is performed, the actual speed of the actuator is determined by the magnitude of the load pressure even if the operator fully operates each operating member 54 and requests the maximum speed of the actuator. become. In this case, the horsepower of the engine 50 becomes the allowable maximum value. Further, for example, when a plurality of actuators are simultaneously operated, even if each operation member 54 is not fully operated, the hydraulic oil is supplied to each actuator, the negative control pressure decreases, and the required flow rate decreases. When the flow exceeds the allowable flow rate determined by the allowable horsepower, the pump tilt angle control is performed so that the allowable flow rate in the horsepower control is obtained.

When the operating member 54 is in the neutral position, that is, when the operator is not operating the operating member 54, the working machine 118 does not perform any work and there is no need to drive the actuator. The pump discharge flow from 52 is desirably zero. For this reason, in this embodiment, each control valve 57-60, 62-65.
Is an open center (spool neutral position and bypass passage 6
1b and 66c are open), and when the operating member 54 is in the neutral position, the hydraulic pump 5
Hydraulic oil supplied from the first and the second passages 52,
It returns to the reservoir tank 70 through 66c.

Thus, when the operating member 54 is at the neutral position, the pressure immediately upstream of the throttles 81, 82 disposed downstream of the bypass passages 61b, 66c increases, and the variable displacement is controlled by the negative flow control. The pump discharge flow rate from the hydraulic pumps 51 and 52 is controlled to decrease. On the other hand, when the operation member 54 is operated, an amount of hydraulic oil corresponding to the operation amount is supplied to each actuator (cylinder or the like), and the remaining hydraulic oil returns to the reservoir tank 70 through the bypass passages 61b and 66c. It has become.

As described above, the throttles (orifices) 81, 82 are provided downstream of the bypass passages 61b, 66c.
Is provided. The pressure sensors 7 are provided in the bypass passages 61b, 66c immediately upstream of the throttles 81, 82.
4, 75 are interposed, and the tilt angles of the hydraulic pumps 51, 52 are controlled based on the pressures immediately upstream of the throttles 81, 82 detected by the pressure sensors 74, 75. .

When the operator operates the operation member 54, the control valves 57 to 6 are controlled according to the operation amount of the operation member 54.
0, 62 to 65 move to bypass passages 61b, 66c.
And the flow rate of the hydraulic oil flowing through the bypass passages 61b and 66c decreases. However, since the diameters of the throttles 81 and 82 are constant, the pressure immediately upstream of the throttles 81 and 82 by the reduced flow rate, that is, the pressure is reduced. The pressure detected by the pressure sensors 74 and 75 decreases, and the tilting angle control of the variable displacement hydraulic pumps 51 and 52 is performed so that the pump discharge flow rate increases in accordance with the reduced pressure.

This means that the pump discharge flow rate is controlled to increase in accordance with the operator's request, that is, the amount of operation of the operation member 54 by the operator. Hydraulic pump 5
This means that the speed of the actuator (each cylinder) can be controlled by controlling the pump discharge flow rate from the pumps 1 and 52.

Here, basic pump tilt angle control in negative flow control by the controller 1 will be described. That is, the controller 1 reads the operating oil pressures (negative control pressures) P _N1 and P _N2 detected by the pressure sensors 74 and 75 and correlates the negative control pressure P _N with the required flow rate Q _N as shown in FIG. The required flow rate Q corresponding to the negative control pressures P _N1 and P _N2 read from the map
_N1, Q _N2 is (specifically required flow rate Q _N1, the pump tilting angle corresponding to Q _N2 V _N1, V _N2) so as to set the.
The required flow rate refers to a flow rate required in negative flow control. Further, the required flow rate Q _N1 (specifically required flow Q corresponding to the negative control pressure P _N1 in FIG
_N1, shows the pump tilting angle V _N1) only the corresponding to.

On the other hand, the controller 1 has a pressure sensor 7
2, 73 detected pump discharge pressure P_P1, P_P2To
Read the pump discharge pressure P_PAnd allowable flow rate Q_PAnd relationship
From the map as shown in FIG.
Discharge pressure P_P1, P_P2Flow rate Q corresponding to_P1, Q_P2(Ingredients
Allowable flow rate Q_P1, Q_P2Tilt angle V corresponding to
_P1, V_P2) Is set. The allowable flow
The amount is determined by driving the first hydraulic pump 51 and the second hydraulic pump 52.
Pump discharge flow according to the allowable horsepower of the moving engine 50
Say. In FIG. 5, the pump discharge pressure P_P1Permission corresponding to
Capacity Q_P1(Specifically, the allowable flow rate Q_P1Pump equivalent to
Tilt angle V_P1) Only.

Then, the controller 1 executes the above-described request flow.
Quantity Q_N1, Q_N2And allowable flow rate Q_P1, Q_P2Compare with
Pump flow (required flow Q_N1, Q_N2Or allowable flow rate
Q_P1, Q _P2) So that the pump tilt angle (pump tilt angle)
V_N1, V_N2Or pump tilt angle V_P1, V_P2) And set
The first hydraulic pump 51 and the second hydraulic pump 51
The output is to the hydraulic pump 52.

Next, the basic operation of the pump tilt angle control in the negative flow control by the controller 1 will be described with reference to the flowchart of FIG. That is, first, at step S10, the negative control pressures P _N1 and P _N2 are read, and at step S20, the pump discharge pressures P _P1 and P _P2 are read.

Next, in step S30, in step S10
Loaded negative control pressure P_N1, P_N2Required flow rate corresponding to
Q_N1, Q_N2Is calculated from the map of FIG.
Pump discharge pressure read in step S20 in step 40
P_P1, P_P2Flow rate Q corresponding to_P1, Q_P2To the map in FIG.
Calculated from the Then, in step S50, the required flow rate Q
_N1, Q_N2Is the allowable flow rate Q_P1, Q_P2Is smaller than
As a result of this determination, the required flow rate Q_N1, Q_N2Is the allowable flow rate
Q_P1, Q _P2If it is determined to be smaller than
Proceeding to S60, the required flow rate Q_N1, Q _N2As the pump flow rate
Set and return. Thereby, the first hydraulic pump 5
The tilt angle of the first and second hydraulic pumps 52 is equal to the required flow rate Q._N1, Q
_N2Is set so as to have a tilt angle corresponding to.

On the other hand, if it is determined that the required flow rates Q _N1 , Q _N2 are equal to or _larger than the allowable flow rates Q _P1 , Q _P2 , the process proceeds to step S
The routine proceeds to 70, where the allowable flow rates Q _P1 and Q _P2 are set as pump flow rates, and the routine returns. Thereby, the first hydraulic pump 51
And the tilt angle of the second hydraulic pump 52 is set to the allowable flow rate Q _P1 , Q _P2
Is set so as to have a tilt angle corresponding to. The control device for a construction machine according to the present embodiment is configured as described above,
Various controls are performed by the controller 1. In this embodiment, if the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are performed simultaneously during the so-called leveling operation, the pump flow in the normal negative flow control is controlled. Pump flow control different from control is performed.

Next, a description will be given of the pump flow rate control when the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are simultaneously performed during the leveling operation, which is a feature of the control device for the construction machine according to the present embodiment. I do. Here, FIG. 1 is a control block diagram for explaining pump flow rate control by the control device of the construction machine according to the present embodiment.

In this embodiment, as shown in FIG. 1, the controller 1 includes a boom-up fine operation determining means (boom fine operation determining means) 2, a stick-in fine operation determining means (stick fine operation determining means) 3, , Bucket-in fine operation determining means (bucket fine operation determining means) 4 and pump tilt angle control means 5. Among them, the boom-up fine operation determination means 2 includes a boom operation member 54a.
It is determined whether or not the fine operation of the boom-up operation has been performed based on the electric signal corresponding to the operation amount of the above operation, and the determination result is output to the pump tilt angle control means 5.

The stick-in fine operation determining means 3 determines whether or not a fine operation of the stick-in has been performed based on an electric signal corresponding to the operation amount of the stick operating member 54b. A signal is output to the angle control means 5. Bucket-in fine operation determination means 4
Determines whether or not the bucket-in fine operation has been performed based on an electric signal corresponding to the operation amount of the bucket operation member 54c, and outputs a result of the determination to the pump tilt angle control means 5 It is.

The pump tilt angle control means 5 includes a boom-up fine operation, a stick-in fine operation, and a stick-in fine operation based on signals from the boom-up fine operation determination means 2, the stick-in fine operation determination means 3, and the bucket-in fine operation determination means 4. And when it is determined that the bucket-in fine operation has been performed simultaneously, the operation amounts of the boom operation member 54a, the stick operation member 54b, and the bucket operation member 54c are adjusted so that the optimum pump flow rate in this operation pattern is obtained. The pump tilt angles of the hydraulic pumps 51 and 52 are controlled based on the electrical signal to be generated.

Specifically, in this embodiment, the pump tilt angle control means 5 controls the tilt angles of the hydraulic pumps 51 and 52 as follows. The pump tilt angle control means 5 basically controls the tilt angles of the hydraulic pumps 51 and 52 by negative flow control. In this negative flow control, the operation member 54 for the boom is used.
a, when the stick operating member 54b and the bucket operating member 54c are operated, these operating members 54a, 54
4b, 54c, the control valves 58 to 60, 6
4 and 65, the hydraulic oil is supplied to the boom drive hydraulic cylinder 105, the stick drive hydraulic cylinder 106, and the bucket drive hydraulic cylinder 107. Therefore, these control valves 58 to 60, 64, The pressure of the hydraulic oil on the downstream side of the pressure sensor 65 (the pressure of the hydraulic oil in the bypass passages 61b and 66c) is reduced.
The tilt angles of the hydraulic pumps 51 and 52 are controlled so that the pump discharge flow rate is increased by being detected by the control unit 5 and used in negative flow control.

For this reason, the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are simultaneously performed. In the case of the so-called leveling operation, the hydraulic pumps 51 and 52 are tilted so that the excessive pump discharge flow rate is obtained. The turning angle control is performed. Therefore, in the present embodiment, the pump tilt angle control means 5 performs the boom-up fine operation,
If it is determined that the stick-in fine operation and the bucket-in fine operation have been performed simultaneously, the boom operation member 54
a, based on electric signals from the stick operating member 54b and the bucket operating member 54c, the pump discharge flow rate is reduced in accordance with the operation amounts of the boom operating member 54a, the stick operating member 54b and the bucket operating member 54c. The pump tilt angles of the hydraulic pumps 51 and 52 are controlled.

When the pump tilt angle control of the hydraulic pumps 51 and 52 is performed as described above, for example, the boost pressure (the differential pressure between the pump discharge pressures of the hydraulic pumps 51 and 52 and the load pressure) becomes a predetermined pressure (approximately). 100 kgf / cm ² ). Therefore, the pump is tilted based on electric signals from the boom operating member 54a, the stick operating member 54b, and the bucket operating member 54c so that the pump discharge pressure becomes higher than the load pressure by a predetermined pressure (about 100 kgf / cm ² ). The turning angle control may be performed.

In order to ensure the simultaneous operability of the boom 103, the stick 104 and the bucket 108, the pressure of the hydraulic oil discharged from the hydraulic pumps 51 and 52 is determined based on the operating pressure of the working machine 118. It is necessary to set the maximum pressure (maximum pressure value). For this reason, the control balance of the negative flow control described above is also set such that the pump discharge flow rate is slightly larger than the total flow rate of the hydraulic oil supplied to each of the cylinders 105 to 107, and the surplus pump discharge flow rate is reduced by the bypass passage throttle of each control valve. It is set to increase the pressure by squeezing.

On the other hand, based on signals from the boom-up fine operation determining means 2, the stick-in fine operation determining means 3, and the bucket-in fine operation determining means 4, the pump tilt angle control means 5 performs the boom-up fine operation, If it is determined that the fine operation and the bucket-in fine operation are not performed at the same time, it is determined that the other operation is to operate any of the boom 103, the stick 104, and the bucket 108 without performing the fine operation. Hydraulic pumps 51, 5 so that the optimal pump flow rate in control is obtained.
2 is for controlling the pump flow rate.

Here, the normal negative flow control means that, as described above, the control valves 57 to 60 and 62 to 65 operate according to the operation amounts of the operation members 54, and the bypass oil passages 61b and 66c The pressure (negative control pressure) generated by the change in the flow rate of the hydraulic oil is determined by the pressure sensors
5 to control the pump tilt angle of the hydraulic pumps 51 and 52 to perform pump flow control. In this case, the pump tilt angle control based on the electric signals from the boom operation member 54a, the stick operation member 54b, and the bucket operation member 54c is not performed.

When the pump tilt angles of the hydraulic pumps 51 and 52 are controlled as described above, the boost pressure becomes, for example, a predetermined pressure (about 150 to 200 kgf / cm ² ).
Therefore, the pump tilt angle control can be performed such that the pump discharge pressure is higher than the load pressure by a predetermined pressure (about 150 to 200 kgf / cm ² ). Here, in the negative flow control, the required pump flow rate also differs depending on the difference in the lever pattern and the difference in the operation amount.

For example, as a difference between the operation patterns of the operation member 54, when the boom-up and the stick-out are linked, the boost pressure is set to a predetermined pressure (about 200 kgf / c).
m ² ), and when linking boom up and bucket out, the pump flow rate is such that the boost pressure becomes a predetermined pressure (about 150 kgf / cm ² ).

On the other hand, differences in the operation amount of the operation member 54 include, for example, a boom-up fine operation, a stick-in operation (operation of about 50 to 100% of the total operation amount) and a bucket-in operation (the total operation amount About 50-100%
When this operation is performed, the operation corresponds to excavation work using the stick 104 and the bucket 108, and the pump discharge pressure is a pressure balanced with the excavation load. In this case, since no boost pressure is generated, a pump flow rate corresponding to the operation amount of the operation member 54 is supplied to secure productivity.

The control device for a construction machine according to the present embodiment is configured as described above, and operates as shown in the flowchart of FIG. 7 in order to perform optimum pump flow control during so-called leveling work. That is, in step A10, an electric signal from each operation member 54 is read, and
Go to 20.

In step A20, it is determined by the boom-up fine operation determining means 2 whether or not the boom-up fine operation has been performed based on the operation amount of the boom operating member 54a. As a result of the determination, when it is determined that the boom-up fine operation has been performed, the process proceeds to step A30, and the stick-in fine operation determination unit 3 performs the fine operation of the stick-in based on the operation amount of the stick operating member 54b. It is determined whether it has been done.

As a result of the determination, when it is determined that the stick-in fine operation has been performed, the process proceeds to step A40, and the bucket-in fine operation determining means 4 further determines whether the bucket-in operation has been performed based on the operation amount of the bucket operating member 54c. It is determined whether or not the fine operation has been performed. If it is determined that the bucket-in fine operation has been performed, the process proceeds to step A50, and the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are simultaneously performed. Done
Since it is considered to be a so-called leveling operation, the leveling operation (boom /
The pump tilt angle control is performed according to the operation amounts of the boom operation member 54a, the stick operation member 54b, and the bucket operation member 54c so that the optimum pump flow rate (at the time of fine operation of the stick / bucket) is obtained, and the process returns.

On the other hand, if it is determined in step A20 that the boom-up fine operation determining means 2 has not performed the boom-up fine operation, the stick-in fine operation determining means 3 has performed the stick-in fine operation determining means 3 in step A30. If it is determined that no bucket-in fine operation is performed by the bucket-in fine operation determining means 4 in step A40, it is determined that the leveling work is not performed in any case. The process proceeds to step A60, in which the pump tilt angle control is performed so that the optimum pump flow rate in the normal negative flow control is obtained, and the process returns.

Here, Table 1 below shows the measurement results of fuel efficiency when the optimum pump flow rate control is performed during the leveling operation. Table 1 shows the measurement results when 10 cycles of the leveling operation (leveling operation) were performed.

[0098]

[Table 1] As shown in Table 1, when the optimum pump flow rate control according to the present embodiment is performed, the fuel efficiency during the leveling operation can be improved by about 25% as compared with the conventional pump flow rate control. The bucket operating member 54c
When the stick or the stick operating member 54b is fully operated, the fuel efficiency is almost the same as in the conventional case.

Therefore, according to the present embodiment, the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are performed based on the operation amounts of the boom operating member 54a, the stick operating member 54b, and the bucket operating member 54c. If performed at the same time, it is determined that the operation is a so-called leveling operation, and the engine that drives the hydraulic pumps 51 and 52 to perform the tilting angle control of the hydraulic pumps 51 and 52 so that the optimum pump flow rate is obtained in the leveling operation. 5
There is an advantage that the output loss of 0 can be suppressed, and the fuel consumption can be improved.

Further, if the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are simultaneously performed based on the operation amounts of the boom operation member 54a, the stick operation member 54b, and the bucket operation member 54c, the leveling operation is performed. It is determined that the operation is performed, and the tilt angle control of the hydraulic pumps 51 and 52 is performed according to the operation amounts of the boom operation member 54a, the stick operation member 54b, and the bucket operation member 54c so that the pump discharge pressure does not excessively increase. Hydraulic pump 5 so as to reduce the pump discharge flow rate.
In order to control the tilt angles of the hydraulic pumps 51 and 5,
There is an advantage that output loss of the engine 50 that drives the engine 2 can be suppressed, and consequently fuel efficiency can be improved.

In the above embodiment, the case where the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are performed has been described. However, the present invention is not limited to this. ),
The present invention can be similarly applied to the case where the stick-out fine operation (stick fine operation) and the bucket open fine operation (bucket fine operation) are performed.

In this case, the boom fine operation determining means 2 is configured to determine whether the boom down fine operation has been performed based on the operation amount of the boom operation member 54a.
The stick fine operation determining means 3 is configured to determine whether a stick-out fine operation has been performed based on the operation amount of the stick operating member 54b,
The bucket fine operation determination means 4 includes a bucket operation member 54.
It is configured to determine whether the bucket open fine operation has been performed based on the operation of c. Then, the pump tilt angle control means 5 performs tilt angle control of the hydraulic pumps 51 and 52 based on the determination results of the boom fine operation determination means 2, the stick fine operation determination means 3, and the bucket fine operation determination means 4. become.

In the above-described embodiment, the case where the present invention is applied to the control device of the construction machine which performs the negative flow control is described. However, the present invention is applied to the control device of the construction machine which performs the positive flow control. You may.

[0104]

As described in detail above, claims 1, 2, 3
According to the control device for a construction machine of the present invention described above, the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation are simultaneously performed based on the operation amounts of the boom operating member, the stick operating member, and the bucket operating member. If this is the case, it is determined that it is a so-called leveling operation, and in order to perform the tilt angle control of the hydraulic pump so that the optimum pump flow rate is obtained in this leveling operation, suppress the output loss of the engine that drives the hydraulic pump. Therefore, there is an advantage that fuel efficiency can be improved.

According to the control apparatus for a construction machine of the present invention, the boom-up fine operation and the stick-in fine operation are performed based on the operation amounts of the boom operating member, the stick operating member, and the bucket operating member. If the operation and the bucket-in fine operation are performed at the same time, it is determined that the operation is a leveling operation, and the operation amount of the operating member for the boom, the operating member for the stick, and the operating member for the bucket is adjusted so that the pump discharge pressure does not excessively increase. Since the tilt angle of the hydraulic pump is controlled so as to reduce the pump discharge flow rate, there is an advantage that the output loss of the engine that drives the hydraulic pump can be suppressed, and the fuel consumption can be improved.

[Brief description of the drawings]

FIG. 1 is a control block diagram for explaining tilt angle control of a hydraulic pump 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 diagram showing a relationship between a required flow rate of negative flow control and a negative control pressure in the control device for a construction machine according to one embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between an allowable flow rate of negative flow control and a pump discharge pressure in the control device for a construction machine according to one embodiment of the present invention.

FIG. 6 is a flowchart for explaining negative flow control in the control device for the construction machine according to the embodiment of the present invention.

FIG. 7 is a flowchart for explaining pump tilt angle control in the control device for a construction machine according to one embodiment of the present invention.

FIG. 8 is a schematic perspective view showing a conventional construction machine.

[Explanation of symbols]

Reference Signs List 1 controller (control means) 2 boom-up fine operation determination means (boom fine operation determination means) 3 stick-in fine operation determination means (stick fine operation determination means) 4 bucket-in fine operation determination means (bucket fine operation determination means) 5 pump Tilt angle control means 51 First hydraulic pump 52 Second hydraulic pump 54 Operating member 54a Operating member for boom 54b Operating member for stick 54c Operating member for bucket 72, 73, 74, 75 Pressure sensor 103 Boom 104 Stick 108 Bucket

Claims (4)

[Claims] 1. A hydraulic pump for discharging hydraulic oil in a tank, a plurality of operating members operated by an operator, and control means for controlling a discharge flow rate from the hydraulic pump, wherein the control means comprises: Boom fine operation determining means for determining whether or not a boom fine operation has been performed based on the operation amount of the boom operating member of the plurality of operating members; and operating the stick operating member of the plurality of operating members. Stick fine operation determining means for determining whether a stick fine operation has been performed based on the amount; and determining whether a bucket fine operation has been performed based on an operation amount of a bucket operating member of the plurality of operating members. Bucket hydraulic operation determining means; and a hydraulic pump of the hydraulic pump based on the determination results of the boom fine operation determining means, the stick fine operation determining means, and the bucket fine operation determining means. Characterized in that it comprises a pump tilting angle control means for rotating angle control, construction machine control system. 2. The hydraulic pump according to claim 2, wherein the plurality of operating members output an electric signal in accordance with an operation amount, and the control unit controls the hydraulic pump based on the electric signals from the plurality of operating members. The control device for a construction machine according to claim 1, wherein tilt angle control is performed. 3. The boom fine operation determining means is configured to determine whether a boom-up fine operation has been performed, and the stick fine operation determining means determines whether a stick-in fine operation has been performed. The bucket fine operation determination means is configured to determine whether a bucket-in fine operation has been performed, and the pump tilt angle control means includes a boom fine operation determination means,
The boom operating member, the stick operating member, and the bucket when the stick fine operation determining means and the bucket fine operation determining means determine that the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation have been performed. 3. The control device for a construction machine according to claim 2, wherein the tilt angle control of the hydraulic pump is performed in accordance with an electric signal from the operating member. 4. The system according to claim 1, wherein said boom fine operation determining means determines whether a boom up fine operation has been performed, and said stick fine operation determining means determines whether a stick-in fine operation has been performed. The bucket operation determination means is configured to determine whether a bucket-in operation has been performed, and the pump tilt angle control means includes the boom fine operation determination means,
When the stick fine operation determining means and the bucket fine operation determining means determine that the boom-up fine operation, the stick-in fine operation, and the bucket-in fine operation have been performed, the discharge flow rate from the hydraulic pump is determined by the fine operation. The control device for a construction machine according to claim 1, wherein the tilt angle control of the hydraulic pump is performed so as to reduce the discharge flow rate from the hydraulic pump when any of the operations is not a fine operation.