JPH11294406A - Hydraulic circuit control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform simultaneous control of a plurality of actuators by a single variable pump and to shorten the molding cycle of an injection molder. SOLUTION: This control device comprises a variable pump 11; a plurality of actuators; control valves disposed corresponding to the respective actuators and controlling an oil pressure fed to the actuator; a variable pump control valve 81 to control an amount of oil discharged from the variable pump 11; and a valve opening control means to control the valve openings of the control valve and the variable pump control valve 81 independently from each other. In this case, since the valve openings of each control valve and the variable pump control valve 81 independently from each other, a plurality of the actuators are simultaneously actuated. This constitution shortens the molding cycle of an injection molder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit control device.

[0002]

2. Description of the Related Art Conventionally, there has been provided a hydraulic circuit in which a single variable pump can be operated to operate a plurality of actuators in order to drive a construction machine. In this case, since there is no need to provide a pump for each actuator, the cost of the hydraulic circuit can be reduced, and the energy efficiency can be improved.

FIG. 2 is a hydraulic circuit diagram of a conventional hydraulic circuit control device. In the figure, 11 is a variable pump, 12 is an oil tank connected to the suction side of the variable pump 11, and the variable pump 11 sucks oil from the oil tank 12 and changes the angle of the built-in swash plate 11a. By changing, an arbitrary amount of oil can be discharged.

A swash plate drive cylinder 13 is provided so that the angle of the swash plate 11a can be changed. The swash plate drive cylinder 13 has a cylinder body 14 and a piston 15 disposed slidably (slidably) within the cylinder body 14, and the inside of the cylinder body 14 is partitioned by the piston 15. First and second oil chambers 17 and 18 are formed. And the piston 15
A rod 21 is protruded toward the first oil chamber 17 from the cylinder body 14.
3 is connected. A rod 22 projects from the piston 15 toward the second oil chamber 18, and the rod 22 is connected to the swash plate 11 a outside the cylinder body 14.

[0005] An oil passage L-1 is provided on the discharge side of the variable pump 11.
Are connected, and the oil passages L-2 and L-3 are branched at a point q1. The variable pump 11 is provided with oil passages L-1, L-
2 and is connected to the load pressure compensating valve 26 via the oil passages L-1 and L-3. The load pressure compensating valve 25 sets the oil pressure supplied through the oil passages L-1 and L-2 to a predetermined value, and then sets the oil pressure in the oil passage L-4.
Is supplied to the manual switching valve 31 via the The manual switching valve 31
Drives the first cylinder 35 based on the supplied hydraulic pressure. Further, the load pressure compensating valve 26 is provided with oil passages L-1, L
After making the oil pressure supplied through -3 a predetermined value, the oil pressure is supplied to the manual switching valve 32 through an oil passage L-5. The manual switching valve 32 is operated by the second cylinder 4 based on the supplied hydraulic pressure.
5 is driven.

The first cylinder 35 has a cylinder body 36 and a piston 37 slidably disposed in the cylinder body 36, and the inside of the cylinder body 36 is partitioned by the piston 37. The piston 3
Reference numeral 7 denotes a head 38 and a rod 39. A first oil chamber 40 is formed on the head 38 side of the cylinder body 36, and a second oil chamber 41 is formed on the rod 39 side.

On the other hand, the second cylinder 45 has a cylinder body 46 and a piston 47 slidably disposed in the cylinder body 46, and the inside of the cylinder body 46 is partitioned by the piston 47. You. The piston 47 includes a head 48 and a rod 49, and a first oil chamber 50 is provided on the head 48 side in the cylinder body 46.
Second oil chambers 51 are formed on the rod 49 side, respectively.

The manual switching valve 31 is connected to an oil passage L-4.
, The oil tank 12 via an oil passage L-6, the second oil chamber 41 via an oil passage L-7, and the first oil chamber 41 via an oil passage L-8. Connected to oil chamber 40, lever b
Are selectively operated to obtain the position A, the position B, and the position N. Then, when the manual switching valve 31 is placed at the position A by operating the lever b, the oil passages L-4 and L-8 and the oil passages L-6 and L-7 are communicated with each other. Oil chamber 4
0 is supplied with oil, the oil is drained from the second oil chamber 41, and the piston 37 is moved to the left in the figure.
When the lever b is operated to place the manual switching valve 31 at the position B, the distance between the oil passages L-4 and L-7 and the oil passage L-
6, L-8 are communicated, oil is supplied to the second oil chamber 41, oil is drained from the first oil chamber 40, and the piston 37 is moved rightward in the figure. Further, when the lever b is operated to place the manual switching valve 31 at the position N, the oil passages L-4, L-6, L-7, and L-8 are shut off from each other, and the position of the piston 37 is maintained. You.

On the other hand, the manual switching valve 32 is connected to an oil passage L-5.
, The oil tank 12 via the oil passage L-11, and the second oil chamber 51 via the oil passage L-12.
Is connected to the first oil chamber 50 via the oil passage L-13,
The position A, the position B, and the position N are taken by selectively operating the lever b. When the manual switching valve 32 is moved to the position A by operating the lever b, the oil passages L-5, L-
13 and between the oil passages L-11 and L-12, oil is supplied to the first oil chamber 50, oil is drained from the second oil chamber 51, and the piston 47 is moved leftward in the figure. It is moved to. When the lever b is operated to place the manual switching valve 32 at the position B, the oil passages L-5, L-12
And the oil passages L-11 and L-13 are communicated, oil is supplied to the second oil chamber 51, oil is drained from the first oil chamber 50, and the piston 47 moves rightward in the figure. Moved. Further, when the lever b is operated to place the manual switching valve 32 at the position N, the oil passages L-5, L-11, L
-12 and L-13 are shut off from each other, and the position of the piston 47 is maintained.

Restrictions 54 and 55 are provided in the manual switching valves 31 and 32, respectively.
The pilot pressure can be taken out from the downstream side through pilot oil passages M-1 and M-2, respectively. The pilot oil passages M-1 and M-2 are connected to the first oil chamber 17 via a shuttle valve 53 and a pilot oil passage M-3. Further, from the oil passage L-1 to the pilot oil passage M-
The pilot pressure can be extracted via 4. Further, pilot oil passage M-4 is connected to second oil chamber 18.

Accordingly, in the swash plate drive cylinder 13, the pilot pressure extracted through the pilot oil passages M-1 to M-3 and the pilot pressure extracted through the pilot oil passage M-4 are used. When the piston 15 is moved in the left-right direction in the figure, for example, in the direction of arrow A, the amount of oil discharged by the variable pump 11 increases.

[0012]

However, in the conventional hydraulic circuit control device, the manual switching valve 3 is not provided.
Because of the use of Nos. 1 and 32, they cannot be applied to an injection molding machine that performs automatic operation according to an electric signal. Further, even if the present invention can be applied to an injection molding machine, it is not possible to simply operate a plurality of actuators, simultaneously perform the control of each actuator, and accurately operate each actuator at a set speed.

An object of the present invention is to solve the problems of the conventional hydraulic circuit control apparatus and to provide a hydraulic circuit control apparatus capable of simultaneously controlling a plurality of actuators by one variable pump. .

[0014]

For this purpose, in the hydraulic circuit control device according to the present invention, a variable pump, a plurality of actuators, and hydraulic pressures provided to the actuators are provided in correspondence with the respective actuators. A control valve for controlling, a variable pump control valve for controlling an amount of oil discharged from the variable pump, and a valve opening control means for independently controlling the valve opening of each of the control valves and the variable pump control valve. Having.

Another hydraulic circuit control device according to the present invention further includes a pressure sensor for detecting a discharge pressure of the variable pump and a hydraulic pressure in an oil chamber of each of the actuators. Then, the valve opening control means controls the valve opening based on the discharge pressure and each hydraulic pressure. In still another hydraulic circuit control device of the present invention, further, a fixed pump for discharging oil supplied to the variable pump control valve, and excess oil other than oil supplied to the variable pump control valve, Oil adjusting means for joining the oil supplied to the control valve.

In still another hydraulic circuit control device according to the present invention, a swash plate position detector for detecting a swash plate position of the variable pump, and an oil amount set corresponding to the swash plate position are provided. Discharge amount limiting means for reducing the valve opening of the control valve corresponding to the actuator selected in advance when the limit value is exceeded.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this case, a case where the hydraulic circuit control device is applied to an injection molding machine will be described. FIG. 1 is a hydraulic circuit diagram of a hydraulic circuit control device according to an embodiment of the present invention. In the figure, 11 is a variable pump, 12 is an oil tank connected to the suction side of the variable pump 11, and the variable pump 11 sucks oil from the oil tank 12 and changes the angle of the built-in swash plate 11a. By changing, an arbitrary amount of oil can be discharged.

A swash plate drive cylinder 13 is provided so that the angle of the swash plate 11a can be changed. The swash plate drive cylinder 13 has a cylinder body 14 and a piston 15 slidably disposed in the cylinder body 14, and the inside of the cylinder body 14 is partitioned by the piston 15, and 2 oil chambers 17, 1
8 are formed. Then, a rod 21 is projected from the piston 15 to the first oil chamber 17 side, and the rod 21
Is connected to a swash plate position detector 61 outside the cylinder body 14. Further, the second oil chamber 18 from the piston 15
A rod 22 is projected to the side, and the rod 22 is connected to the swash plate 11 a outside the cylinder body 14.

The swash plate position detector 61 detects the position of the swash plate 11a, that is, the position of the swash plate, and when the amount of oil set corresponding to the swash plate position exceeds the limit value, will be described later. Mold opening / closing cylinder 73 as a first actuator and ejector cylinder 7 as a second actuator
4. The amount of oil supplied to one of the four selected in advance is reduced. For this purpose, when a detection signal generated by the swash plate position detector 61 is sent to the control device 85, the discharge amount limiting means (not shown) of the control device 85 sends a signal to the solenoids a of the mold opening / closing cylinder 73 and the ejector cylinder 74. One of the supplied valve opening commands V ₁ and V ₂ is reduced, and each valve opening of a mold opening / closing control valve 71 as a first control valve and an ejector control valve 72 as a second control valve, which will be described later. Smaller.

An oil passage L-21 is connected to the discharge side of the variable pump 11, and the oil passage L-2 is connected at a point q1.
2. L-23 branches. And the variable pump 11
Is a mold opening / closing control valve 71 through oil passages L-21 and L-22.
Connected to the ejector control valve 72 via oil passages L-21 and L-23. A fixed pump 62 sucks oil from the oil tank 12 and discharges a fixed amount of oil. An oil passage L-18 is connected to the discharge side of the fixed pump 62. The fixed pump 62 is connected to a relief valve 63 as an oil adjusting means via the oil passage L-18, and an oil passage L-19. Is connected to the oil passage L-22. The relief valve 63
The hydraulic pressure is discharged from the fixed pump 62 to the oil passage L-18 and supplied to the variable pump control valve 81 via the oil passage L-33 to a predetermined value. The oil is discharged to the oil passage L-19 and merges with the oil supplied to the mold opening / closing control valve 71 via the oil passage L-22.

The mold opening / closing control valve 71 is arranged in correspondence with the mold opening / closing cylinder 73, and the ejector control valve 72 is arranged in correspondence with the ejector cylinder 74, and controls the supplied hydraulic pressure to be controlled. Hydraulic pressure is supplied to the mold opening / closing cylinder 73 and the ejector cylinder 74 to be operated. The mold opening / closing cylinder 73 has a cylinder main body 36 and a piston 37 slidably disposed in the cylinder main body 36, and the inside of the cylinder main body 36 is partitioned by the piston 37. The piston 37 includes a head 38 and a rod 39, and a first oil chamber 40 is provided on the head 38 side in the cylinder body 36.
Second oil chambers 41 are formed on the rod 39 side, respectively.

On the other hand, the ejector cylinder 74 has a cylinder body 46 and a piston 47 slidably disposed in the cylinder body 46.
The inside of the cylinder body 46 is defined by 7. The piston 47 includes a head 48 and a rod 49, and a first oil chamber 50 is provided on the head 48 side in the cylinder body 46.
However, second oil chambers 51 are formed on the rod 49 side in the cylinder body 46, respectively.

The mold opening / closing control valve 71 is provided with an oil passage L-
22, the variable pump 11 and the oil passages L-22, L-1
9, a relief valve 63, an oil tank 12 via an oil passage L-26, and a second oil chamber 41 via an oil passage L-27.
Is connected to the first oil chamber 40 via an oil passage L-28,
Positions A, B, and N are taken by selectively driving the solenoid a.

When the solenoid a is driven to place the mold opening / closing control valve 71 at the position A, the oil passages L-22, L-2
8, and between the oil passages L-26 and L-27,
Oil is supplied to the first oil chamber 40, oil is drained from the second oil chamber 41, and the piston 37 is moved leftward in the drawing to close the mold. When the solenoid a is driven to place the mold opening / closing control valve 71 at the position B, the oil passage L
-22, L-27 and the oil passages L-26, L-28 are communicated, oil is supplied to the second oil chamber 41, oil is drained from the first oil chamber 40, and the piston 37 Is moved rightward (in the direction of arrow B) in the figure to open the mold. Further, when the solenoid a is driven to place the mold opening / closing control valve 71 at the position N, the oil passages L-22, L-2
6, L-27 and L-28 are shut off from each other and the piston 3
7 is maintained.

On the other hand, the ejector control valve 72 is connected to the variable pump 11 via the oil passage L-23 and the oil passages L-22 and L-22.
-19, a relief valve 63, an oil tank 12 via an oil passage L-29, and a second oil chamber 5 via an oil passage L-30.
1 is connected to the first oil chamber 50 via an oil passage L-31, and takes a position A, a position B and a position N by selectively driving the solenoid a.

When the ejector control valve 72 is moved to the position A by driving the solenoid a, the oil passages L-23 and L
−31 and the oil passages L-29 and L-30 are communicated, oil is supplied to the first oil chamber 50, oil is drained from the second oil chamber 51, and the piston 47 is moved to the left in FIG. (In the direction of arrow C), and ejecting by an ejector pin (not shown) is performed. When the solenoid a is driven to place the ejector control valve 72 at the position B, the oil passages L-23 and L-30, and the oil passages L-29 and L
-31 are communicated, oil is supplied to the second oil chamber 51, oil is drained from the first oil chamber 50, and the piston 4
7 is moved to the right in the figure, and the ejector pin is retracted. Further, when the solenoid a is driven to place the ejector control valve 72 at the position N, the oil passages L-23, L-29, L-30, and L-31 are shut off from each other, and the position of the piston 47 is maintained. You.

A variable pump control valve 81 is provided for controlling the amount of oil discharged from the variable pump 11 by operating the swash plate drive cylinder 13, that is, the discharge amount. The variable pump control valve 81 connects the first oil chamber 17 via an oil passage L-35, the second oil chamber 18 via an oil passage L-32, and the oil passages L-33 and L-18. Fixed pump 62 via the oil passage L-34 and the oil tank 1 via the oil passage L-34.
2, the position A, the position B and the position N are taken by selectively driving the solenoid a.

When the solenoid a is driven to place the variable pump control valve 81 at the position A, the oil passages L-35, L-35
−33, and between the oil passages L-32 and L-34, oil is supplied to the first oil chamber 17, oil is drained from the second oil chamber 18, and the piston 15 is moved to the right in the figure. (In the direction of arrow A) to increase the discharge amount. When the solenoid a is driven to place the variable pump control valve 81 at the position B, the oil passages L-35, L-34
And the oil passages L-32 and L-33 are communicated, oil is supplied to the second oil chamber 18, oil is drained from the first oil chamber 17, and the piston 15 is moved to the left in the figure. By being moved, the discharge amount is reduced. Further, when the solenoid a is driven to place the variable pump control valve 81 at the position N, the oil passages L-32, L-33, L-34, L-
35 are shut off from each other, and the position of the piston 15 is maintained.

As described above, the variable pump control valve 81 supplies the hydraulic pressure discharged from the fixed pump 62 and adjusted by the relief valve 63 to the swash plate drive cylinder 13 to operate the swash plate drive cylinder 13. . by the way,
In order to control the variable pump control valve 81, the mold opening / closing cylinder 73, and the ejector cylinder 74, an oil passage L-2
1 has a pressure sensor 91 and the second oil chamber 41 has a pressure sensor 9.
2, a pressure sensor 93 is provided in the first oil chamber 40, a pressure sensor 94 is provided in the second oil chamber 51, and a pressure sensor 95 is provided in the first oil chamber 50. And the pressure sensor 9
Discharge pressure of the variable pump 11 by 1, that is, oil pressure P ₀ is detected in the oil passage L-21, the pressure sensor 92 to 95, the second hydraulic P ₁₁ in the oil chamber 41, a first The oil pressure P ₁₂ in the oil chamber 40, the oil pressure P ₂₁ in the second oil chamber 51, and the oil pressure P ₂₂ in the first oil chamber 50 are detected and sent to the control device 85.

When an operation device (not shown) is operated to input various commands such as a mold opening speed command R ₁₁ and an ejector ejection speed command R ₂₂ to the control device 85, the command and the hydraulic pressure P ₀ are input. , P ₁₁ , P ₁₂ , P ₂₁ , and P ₂₂ , valve opening commands V ₁ , V ₂ , and V _{0 of} the mold opening / closing control valve 71, the ejector control valve 72, and the variable pump control valve 81 are calculated, respectively. The valve opening commands V ₁ , V ₂ , and V ₀ are output to the respective solenoids a of the mold opening / closing control valve 71, the ejector control valve 72, and the variable pump control valve 81, and the mold opening / closing control valve 71, the ejector control valve 72 And each valve opening of the variable pump control valve 81 is controlled.

Therefore, the mold opening / closing control valve 71 and the ejector control valve 72 can be controlled simultaneously and independently of each other. For example, the mold opening in the mold clamping device and the protrusion by the ejector pin can be performed simultaneously.
The molding cycle of the injection molding machine can be shortened. Next, a case where the mold opening and the protrusion by the ejector pin are performed simultaneously will be described.

FIG. 3 is a diagram showing a procedure of a first valve opening command calculation process according to the embodiment of the present invention. FIG. 4 is a diagram showing a second valve opening command calculation process according to the embodiment of the present invention. FIG. 5 is a diagram illustrating a procedure of an operation, and FIG. 5 is a diagram illustrating a procedure of an operation of a third valve opening command calculation process in the embodiment of the present invention. The amount of oil discharged from the variable pump 11 (FIG. 1) and supplied to the second oil chamber 41 of the mold opening / closing cylinder 73 is controlled by a mold opening / closing control valve 71, and the mold opening speed corresponding to the amount of oil is controlled. in but mold opening is performed, the discharge pressure of the amount of the oil is variable pump 11, i.e., the square root of the difference between the hydraulic pressure P ₁₁ in the hydraulic P ₀ in the oil passage L-21 in the second oil chamber 41 Proportional. Therefore, as shown in FIG. 3, the mold opening speed command R ₁₁ is input to the control unit 85, not shown, of the control device 85 calculating means reads the pressure P _0, P _11, the mold opening speed command R _{Based on 11} and the oil pressures P ₀ and P ₁₁ , a valve opening command V ₁ V ₁ = K ₁ · R ₁₁ / √ (P ₀ −P ₁₁ ) is calculated. Here, K ₁ is a constant.

The valve opening control means (not shown) of the control device 85 transmits the valve opening command V ₁ to the mold opening / closing control valve 71.
Is output to the solenoid a. Similarly, the amount of oil discharged from the variable pump 11 and supplied to the first oil chamber 50 of the ejector cylinder 74 is controlled by an ejector control valve 72, and the ejection is performed at an ejector speed corresponding to the amount of oil. dividing, but the amount of the oil is proportional to the square root of the difference between the pressure P ₂₂ the hydraulic P ₀ in the oil passage L-21 in the first oil chamber 50. Therefore, as shown in FIG.
When the ejector protrusion the speed command R ₂₂ is inputted to 5, wherein the calculating means reads the pressure P _0, P _22, based on the ejector protrudes speed command R ₂₂ and hydraulic P _0, P _22, the valve opening degree command V Calculate ₂ V ₂ = K ₂ · R ₂₂ / √ (P ₀ -P ₂₂ ). Here, K ₂ is a constant.

Then, the valve opening control means outputs the valve opening command V ₂ to the solenoid a of the ejector control valve 72. Further, the variable pump 11 is controlled by a variable pump control valve 81, and the hydraulic pressure P ₀ in the oil passage L-21 is controlled.
But from any higher of the second oil chamber pressure P ₁₁ in the 41 and the first hydraulic P ₂₂ in the oil chamber 50, that set to be higher by a preset additional hydraulic P _A preferable. Therefore, as shown in FIG. 5, the calculating means reads the pressure _{P 0, P 11, P 22} , based on the ejector protrudes speed command R ₂₂ and hydraulic _{P 0, P 11, P 22} ,
Pump pressure command P _OR for operating the variable pump 11
Is calculated. In this case, if it is P _11> P _22, it becomes _{P OR = P 11 + P A} , when is a P _22> P _11, becomes _{P OR = P 22 + P A} .

Subsequently, a valve opening command V ₀ V ₀ = K ₀ (P _OR -P ₀ ) is calculated based on the pump pressure command P _OR . Here, K ₀ is a constant. Then, the valve opening control means outputs the valve opening command V ₀ to the solenoid a of the variable pump control valve 81.

As described above, the oil discharged by one variable pump 11 is simultaneously and independently supplied to the mold opening / closing cylinder 73 and the ejector cylinder 74, and the mold opening / closing cylinder 73 and the ejector cylinder 74 are simultaneously operated. It can control the mold opening speed of the clamping device, and control the ejection speed of the ejector pin of the ejector device, and operate the mold clamping device accurately at the set mold opening speed,
The ejector device can be operated accurately at the set ejection speed. Therefore, the molding cycle can be shortened.

The valve opening commands V ₁ , V ₂ , and V ₀ are output to the solenoids a of the mold opening / closing control valve 71, the ejector control valve 72, and the variable pump control valve 81, respectively.
Since each mold opening / closing control valve 71, the ejector control valve 72, and the variable pump control valve 81 are electrically operated, the control accuracy of each mold opening / closing control valve 71, the ejector control valve 72, and the variable pump control valve 81 is controlled. Can be higher.

In the present embodiment, the mold opening / closing cylinder 73 and the ejector cylinder 74 are used as actuators.
However, not only three or more hydraulic cylinders can be used, but also a hydraulic motor can be used in addition to the hydraulic cylinders. Further, in the present embodiment, the case where the mold opening and the ejection of the ejector pin are performed at the same time is described.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0040]

According to the present invention, as described above, in the hydraulic circuit control device, the variable pump, the plurality of actuators, and the hydraulic pressures provided to the actuators are provided in correspondence with the respective actuators. A control valve for controlling, a variable pump control valve for controlling an amount of oil discharged from the variable pump, and a valve opening control means for independently controlling the valve opening of each of the control valves and the variable pump control valve. Having.

In this case, the valve opening of each control valve and the variable pump control valve is controlled independently, so that a plurality of actuators can be operated simultaneously. Therefore, the molding cycle of the injection molding machine can be shortened. The other hydraulic circuit control device of the present invention further includes a pressure sensor for detecting a discharge pressure of the variable pump and a hydraulic pressure in an oil chamber of each actuator.

The valve opening control means controls the valve opening based on the discharge pressure and each oil pressure. in this case,
Since the actuator can be operated electrically, control accuracy can be increased.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulic circuit control device according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a conventional hydraulic circuit control device.

FIG. 3 is a diagram showing a procedure of an operation of a first valve opening command calculation process in the embodiment of the present invention.

FIG. 4 is a diagram showing a procedure of an operation of a second valve opening command calculation process in the embodiment of the present invention.

FIG. 5 is a diagram showing a procedure of an operation of a third valve opening command calculation process in the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Variable pump 11a Swash plate 61 Swash plate position detector 62 Fixed pump 63 Relief valve 71 Type opening / closing control valve 72 Ejector control valve 73 Type opening / closing cylinder 74 Ejector cylinder 81 Variable pump control valve 85 Controller 91-95 Pressure sensor P ₀ , _{P 11, P 12, P 21} , P 22 hydraulic V _0, V _1, V ₂ valve opening instruction

Claims (4)

[Claims] (A) a variable pump, (b) a plurality of actuators, (c) a control valve disposed to correspond to each of the actuators, and controlling a hydraulic pressure supplied to the actuators; A) a variable pump control valve for controlling the amount of oil discharged from the variable pump; and (e) a valve opening control means for independently controlling the valve opening of each of the control valve and the variable pump control valve. A hydraulic circuit control device, characterized in that: (A) a pressure sensor for detecting a discharge pressure of the variable pump and a hydraulic pressure in an oil chamber of each of the actuators; and (b) the valve opening control means controls the discharge pressure and each of the hydraulic pressures. The hydraulic circuit control device according to claim 1, wherein the valve opening is controlled based on: 3. A fixed pump that discharges oil supplied to the variable pump control valve, and (b) surplus oil other than oil supplied to the variable pump control valve is supplied to the control valve. And oil adjusting means for joining the oil to be mixed.
2. The hydraulic circuit control device according to claim 1. 4. A swash plate position detector for detecting a swash plate position of the variable pump, and (b) when an oil amount set corresponding to the swash plate position exceeds a limit value. 2. The hydraulic circuit control device according to claim 1, further comprising discharge amount limiting means for reducing a valve opening of a control valve corresponding to a previously selected actuator.