JPH11303814A - Pressurized oil supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set the motion of a hydraulic actuator arbitrarily by changing the supply flow rate of the hydraulic actuator and the flow out flow rate to a tank of a return pressurized oil independently. SOLUTION: The delivery pressurized oil of a hydraulic pimp 1 is supplied to a hydraulic actuator 10 by a meter in selector valve 3 and its return pressurized oil is poured out to a tank 14 by the meter in selector valve 13. The meter in selector valve 3 is switched to the meter out selector valve 13 by the order of a controller independently and a meter in opening area and a mete out opening area can be set independently and arbitrarily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for supplying hydraulic oil discharged from a hydraulic pump to a hydraulic actuator used in a hydraulic system of a construction machine.

[0002]

2. Description of the Related Art A pressure oil supply device disclosed in Japanese Patent Publication No. 6-41764 has been proposed. The pressure oil supply device includes a hydraulic pump, a switching valve, a hydraulic actuator, and a control unit, and controls a meter-in opening area of the switching valve based on an operation command value or the like input to the control unit. With this pressure oil supply device, it is possible to supply discharge pressure oil from a hydraulic pump to a plurality of hydraulic actuators and simultaneously operate hydraulic actuators having different loads.

[0003]

The switching valve of the above-described pressure oil supply device has a pump port, a tank port, a first actuator port and a second actuator port, and one of the pump port and the first and second actuator ports. And the tank port and the other of the first and second actuator ports communicate with each other.
-While being supplied to the hydraulic actuator from one of the second actuator ports, return pressure oil of the hydraulic actuator is discharged to the tank port from the other of the first and second actuator ports.

Because of this, the pump port and the first
Controlling one opening area (meter-in opening area) of the second actuator port and the first and second tank ports
Since the opening area of the actuator port (meter-out opening area) is uniquely determined, the flow rate of the return pressure oil of the hydraulic actuator flowing to the tank is determined according to the flow rate of the pressure oil supplied to the hydraulic actuator.

For example, if the meter-in opening area is enlarged and a large flow is supplied to the hydraulic actuator, the meter-out opening area is large and the return pressure oil of the hydraulic actuator flows into the tank at a large flow rate. If the meter-in opening area is reduced and a small flow rate is supplied to the hydraulic actuator, the meter-out opening area is small and the return pressure oil of the hydraulic actuator flows into the tank at a small flow rate.

For this reason, in the conventional pressure oil supply device, the operation of the hydraulic actuator is determined by the meter-in opening area, and the operation of the hydraulic actuator cannot be arbitrarily set.
On the other hand, the preferable operation of the hydraulic actuator differs depending on the type of driven body to be driven, how to use the driven body, and the like. For example, in the case of a hydraulic actuator (turning hydraulic motor) that turns the upper body of a hydraulic shovel, the flow rate of return pressure oil flowing into the tank is reduced to generate back pressure, so that when the upper body stops, the upper body stops. It is preferable to prevent the vehicle body from turning due to inertial force. In the case of a hydraulic actuator (boom cylinder) that swings the boom of a hydraulic shovel up and down, when the boom swings downward with no load, the hydraulic oil returns. It is preferable that the outflow flow rate to the tank is reduced to generate a back pressure so that the boom does not swing downward by its own weight.

Therefore, an object of the present invention is to provide a pressure oil supply device which can solve the above-mentioned problems.

[0008]

A first aspect of the present invention is a hydraulic pump 1, a hydraulic actuator 10 provided in a discharge circuit of the hydraulic pump 1, and a hydraulic pump 1 and a hydraulic actuator 10. In a pressure oil supply device provided with a meter-in switching valve 3 that controls a meter-in flow rate in accordance with a differential pressure between a pump pressure and a load pressure, a return circuit from the hydraulic actuator 10 to the tank 14 includes the meter-in switching valve 3 Is a pressure oil supply device provided with a meter-out switching valve 13 for controlling an independent meter-out flow rate.

According to the first aspect, the meter-in opening area and the meter-out area opening are independently controlled, and the supply flow rate to the hydraulic actuator 10 and the return flow rate flowing out to the tank 14 can be arbitrarily changed. The operation of the hydraulic actuator 10 can be set arbitrarily. For example, it can be set to perform an operation suitable for the type of the driven body, the usage of the driven body, and the like.

According to a second aspect of the present invention, a hydraulic pump 1, a hydraulic actuator provided in a discharge circuit of the hydraulic pump 1 for operating a working machine, and a meter-in flow rate provided between the hydraulic pump 1 and the hydraulic actuator are controlled. In a pressure oil supply device comprising a meter-in switching valve 3 and a meter-out switching valve 13 provided in a return circuit from the hydraulic actuator to the tank 14 for controlling a meter-out flow rate independently of the meter-in switching valve 3, Switching valve 3
Means for controlling the meter-in opening area according to the differential pressure between the pump pressure and the load pressure and the work content;
And a means for controlling the pressure oil independently according to the work content.

According to the second invention, the meter-in switching valve 3
Of the meter-out switching valve 13 is controlled independently of the meter-in switching valve 3 in accordance with the work content. Thereby, the meter-in flow rate and the meter-out flow rate according to the work content of the work machine can be obtained independently, so that the operation of the work machine can be adapted to the work content.

In a third aspect based on the second aspect, the work content includes a type of work, an operation amount of an operation lever for outputting a signal for operating the hydraulic actuator, a posture of the work implement, and a load of the hydraulic actuator. It is a pressure oil supply device that is at least one of pressure and the like.

According to the third aspect, the meter-in flow rate and the meter-out flow rate can be independently controlled according to the type of work, the operation amount of the operation lever, the posture of the work implement, and the load pressure of the hydraulic actuator. The operation can be adapted to the type of work, the operation amount of the operation lever, the posture of the work implement, the load pressure of the hydraulic actuator, and the like.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG.
A meter-in switching valve 3 is provided in the discharge path 2 of the first embodiment. The meter-in switching valve 3 includes a pump port 4 and first and second actuator ports 5 and 6. The meter-in switching valve 3 is held by a spring 7 at a neutral position A that shuts off each port. The operation is switched to the first position B, and the operation is switched to the second position C by the pressure oil acting on the second pressure receiving portion 9.

When the meter-in switching valve 3 is at the first position B, the pump port 4 communicates with the first actuator port 5, and when the meter-in switching valve 3 is at the second position C, the pump port 4 communicates with the second actuator port 6. This opening area is the first and second
It is proportional to the pressure acting on the pressure receiving parts 8 and 9.

The first and second actuator ports 5,
Reference numeral 6 denotes a first chamber 11 and a second chamber 12 of the hydraulic actuator 10.
Connected to each other. This hydraulic actuator 10
The first and second chambers 11 and 12 are connected to a tank 14 by a meter-out switching valve 13.

The meter-out switching valve 13 has first and second
It has return ports 15 and 16 and a tank port 17, and is held at a neutral position A where each port is shut off by a spring 18.
The second position C is set with the pressure oil of 0.

When the meter-out switching valve 13 is at the first position B, the first return port 15 communicates with the tank port 17, and when at the second position C, the second return port 16 communicates with the tank port 17. The opening area is proportional to the pressure acting on the first and second pressure receiving portions 19 and 20.

A pump pressure sensor 21 for detecting the pressure of the pressure oil discharged from the hydraulic pump 1 (hereinafter referred to as a pump pressure), a first meter-in pressure sensor 22 for detecting the pressure of the output pressure oil of the first actuator port 5, and a second meter. A second meter-in pressure sensor 23 for detecting the output pressure oil of the actuator port 6 and a meter-out pressure sensor 24 for detecting the pressure of the output pressure oil of the tank port 17 are provided. Hydraulic pump 1
A discharge valve 2 is provided with a relief valve 25 and a bleed valve 26.

As shown in FIG. 2, the output pressure oil of the electromagnetic proportional pressure control valve 30 is supplied to each of the pressure receiving portions. Each electromagnetic proportional pressure control valve 30 outputs a pressure proportional to the amount of current supplied to the solenoid 31. Each solenoid 31 is connected to a controller 32
Is controlled.

The operation direction and operation stroke of the operation lever 33 are detected by a potentiometer 34, and the detected signals are input to the controller 32 as an operation direction command and an operation amount command value. The pressure detected by each pressure sensor is input to the controller 32.

The controller 32 includes a meter-in opening area control unit 35 and a meter-out opening area control unit 36. The meter-in opening area control unit 35 calculates a desired meter-in opening area based on the manipulated variable command value, the detected pressure of each pressure sensor, the content of work, and the like, calculates an energization amount corresponding to the meter-in opening area, and calculates the calculated energization. An electromagnetic proportional pressure control valve 3 for supplying a pressure to the first or second pressure receiving portion 8, 9 of the meter-in switching valve 3 based on an operation direction command.
The solenoid 31 of 0 is energized.

The meter-out opening area controller 36 controls the first and second meter-out switching valves 13 based on an operation direction command.
It is determined which of the two electromagnetic proportional pressure control valves 30 that outputs pressure oil to the second pressure receiving units 19 and 20 is to be energized, and a meter-out opening area is calculated in accordance with an operation amount command value, work content, and the like. An amount of current corresponding to the calculated meter-out opening area is calculated, and the calculated amount of current is supplied to the solenoid 31.

The output pressure of the electromagnetic proportional pressure control valve 30 is proportional to the amount of current supplied to the solenoid 31, and the meter-in switching valve 3,
Since the opening area of the meter-out switching valve 13 is proportional to the pressure of the pressure receiving portion, the opening areas of the meter-in switching valve 3 and the meter-out switching valve 13 are proportional to the amount of current supplied to the solenoid 31.

The meter-in opening area control section 35 has a plurality of control functions. Next, the first control function will be described.
First, the pump pressure P detected by the pump pressure sensor 21
₀ (meter-in upstream pressure) and the hydraulic actuator 1 detected by the first or second meter-in pressure sensors 22 and 23
Q = c in accordance with the flow rate Q set differential pressure of the load pressure P ₁ 0
From the formula of A square root (P ₀ −P ₁ ), the meter-in opening area A
Is calculated. The set flow rate Q is the discharge amount of the hydraulic pump 1 in this case. When the input operation amount command value is the maximum (operation lever full stroke), the set flow rate is reduced as the operation amount instruction value decreases with the discharge amount of the hydraulic pump 1.

An amount of current corresponding to the meter-in opening area calculated as described above is calculated, and the calculated amount of current is calculated as
Power is supplied to the solenoid 31 of the electromagnetic proportional pressure control valve 30 that supplies pressure oil to one of the second pressure receiving portions 8 and 9.

As described above, the first control function controls the meter-in opening area of the meter-in switching valve 3 according to the differential pressure between the pump pressure and the load pressure, and also controls the operation amount of the operation lever 33. The first control function is the operation lever 33
Select when is operated alone.

The meter-out opening area control unit 36 also has a plurality of control functions, and selects the first control function when the meter-in opening area control unit 35 selects the first control function. The first of the meter-out opening area control unit 36
The control function of (1) energizes the solenoid 31 of the electromagnetic proportional pressure control valve 30 with an amount of electricity proportional to the manipulated variable command value as shown by the solid line in FIG. 3, and sets the meter-out opening area to a size corresponding to the manipulated variable command value. .

Next, the second control function of the meter-in opening area control unit 35 and the meter-out opening area control unit 36 will be described. For example, the hydraulic actuator 10 is a cylinder for a boom of a hydraulic shovel, and the meter-in switching valve 3
When the boom cylinder is retracted by supplying the pressurized oil to the first chamber 11 by contracting the boom cylinder and setting the
It is determined whether the pressure detected by the meter-in pressure sensor 22 (load pressure of the boom cylinder) is lower or higher than a set pressure.
If it is lower, the meter-in opening area control unit 35 selects the second control function, and the meter-out opening area control unit 36 selects the second control function. If it is higher, the above-described first control function is selected.

The second control function of the meter-out opening area control unit 36 is as follows. When the operation lever 33 is operated at full stroke and the maximum operation amount command value is input, the maximum energization amount is reduced as shown by the dotted line in FIG. 3 to reduce the meter-out opening area. Meter-in opening area controller 3
The second control function of No. 5 is as follows. Operation lever 33
Is operated at full stroke to reduce the set flow rate when the maximum manipulated variable command value is input, thereby reducing the meter-in opening area.

As described above, when the pressure of the chamber (first chamber 11) for reducing the boom cylinder is lower than the set pressure, that is, when the boom is swung downward with no load, the meter-out opening area is reduced. Since the pressure becomes smaller and a back pressure is generated in the chamber (second chamber 12) extending the boom cylinder, it is possible to prevent a vacuum from being generated in the reduced chamber.

When the pressure of the chamber (first chamber 11) for reducing the boom cylinder is higher than the set pressure, that is, when the boom is swung downward while the bucket is pressed against the ground and excavated, the meter-in opening area is set. And the meter-out opening area increases, and the pressure oil in the chamber (the second chamber 12) extending the boom cylinder flows out smoothly to the tank, and no back pressure is generated in that chamber, so that it is supplied to the shrinking chamber. Since the boom swings downward with a force corresponding to the pressure of the pressurized oil, the excavating force is large.

As described above, the meter-in opening area of the meter-in switching valve 3 and the meter-out opening area of the meter-out switching valve 13 are controlled independently of each other. The flow rate of the return pressure oil can be set arbitrarily and independently, and the operation of the hydraulic actuator can be set arbitrarily.

Next, a case where other control functions of the meter-in opening area control unit 35 and the meter-out opening area control unit 36 are applied to a hydraulic system of a hydraulic shovel will be described as an example. As shown in FIG. 4, an upper vehicle body 42 is attached to a lower vehicle body 41 having left and right traveling bodies 40 so as to be pivotable by a hydraulic motor 43 for turning, and a boom 44 is vertically moved by a boom cylinder 45 to the upper vehicle body 42. It is mounted swingably.
An arm 46 is attached to the boom 44 by an arm cylinder 47 so as to be swingable up and down. A bucket 48 is attached to the arm 46 by a bucket cylinder 49 so as to swing up and down. The left and right traveling bodies 40 travel by the left and right traveling hydraulic motors 50 and 51.

The turning angle of the upper body 42 is detected by a turning angle sensor 52, and the angle of the boom 44 is
3, the angle of the arm 46 is detected by the arm angle sensor 54.
The angle of the bucket 48 is detected by the bucket angle sensor 5
5 is detected.

As shown in FIG. 5, the boom switching valve 56,
The arm switching valve 57, the bucket switching 58, the turning switching valve 59, the left traveling switching valve 60, and the right traveling switching valve 61 are formed by the meter-in switching valve 3 and the meter-out switching valve 13, respectively. The valve 3 and the meter-out switching valve 13 are the same as those shown in FIG.

The pump port 4 of each meter-in switching valve 3 is connected in parallel to the discharge path 2 of the hydraulic pump 1, and the tank port 17 of each meter-out switching valve 13 is connected in parallel to the tank 14. The output pressure of the electromagnetic proportional pressure control valve 30 is supplied to each pressure receiving portion of each of the meter-out switching valves 3 and 13 as shown in FIG.

As shown in FIG. 6, the operating lever 7 for the boom is used.
0, arm operation lever 71, bucket operation lever 7
2, turning operation lever 73, left traveling operation lever 74,
When the right travel operation lever 75 is operated, the operation direction command and the operation amount command value are output from the potentiometer 34 to the controller 3.
2 is input. A plurality of work modes are input to the controller 32 from a plurality of different mode switches 76, 77, 78.

The operation modes include 45-degree loading, 90-degree loading, 135-degree loading, 180-degree loading, and deep groove loading. 45 degree loading means boom 44, arm 46,
After excavating the bucket 46 by swinging the bucket 46 up and down, the upper body 42 is turned 45 degrees while swinging the boom 44 upward to a loading position such as a bed of a dump truck, and the earth and sand in the bucket is discharged to dump. This is a work mode in which the upper body 42 is again turned 45 degrees in the opposite direction after loading on the truck bed and the boom 44 is swung downward to set the excavation position. 90 degree loading, 135 degree loading, 1
The 80-degree loading is a work mode in which the upper vehicle body 42 turns 90, 135, and 180 degrees while swinging the boom 44 up and down as described above.

The 45 degree loading operation mode is the controller 3
When the signal is input to the controller 2 and the turning signal is input to the controller 32 from the boom operation lever 70 and the turning signal from the turning operation lever 73, the meter-in opening area control unit 35 selects the third control function. The third control function is as follows. Electromagnetic proportional pressure control valve 30 that outputs pressure oil to meter-in switching valve 3 of boom switching valve 56
As shown in FIG. 7, the maximum energizing amount to the solenoid 31 (the energizing amount when the operating lever is operated at a full stroke) I-1 is large, and electromagnetic pressure is output to the meter-in switching valve 3 of the switching valve 59 for turning. As shown in FIG. 8, the maximum energization amount (the energization amount when the operation lever is operated by a full stroke) I-2 to the solenoid 31 of the proportional pressure control valve 30 is reduced. That is, the ratio of the supply flow rate _{Q 2} of the supply flow rate to _{Q 1} to the boom cylinder 45 to the swing hydraulic motor _{43 (Q 2 / Q 1)} , namely to reduce the flow rate distribution ratio.

The meter-out opening area control section 36 selects the first control function and the second control function, and switches the boom switching valve 5.
6 is controlled by the first control function, and the meter-out switching valve 13 of the turning switching valve 59 is controlled by the second control function.
Is controlled by the control function.

As a result, the meter-in opening area of the boom switching valve 56 becomes larger than the meter-in opening area of the turning switching valve 59, so that a large amount of pressure oil is supplied to the boom cylinder 45, and Since the supply flow rate is reduced, the boom raising speed is high and the turning speed is low.

Therefore, the boom 44 rises to a predetermined height while the upper body 42 turns 90 degrees.

Meter-out switching valve 1 of the switching valve 59 for turning
Solenoid 3 of the electromagnetic proportional control valve 30 that outputs pressure oil to the solenoid 3
1, the amount of electricity is small, and the meter-out opening area is small.
As a result, the return pressure oil of the turning hydraulic motor 43 is throttled by the meter-out switching valve 13 to generate back pressure, and when the turning operation lever 73 is returned to the neutral position, the turning hydraulic motor 4
3 stops immediately and does not turn due to inertial force. When the earth and sand in the bucket 48 are loaded on the bed of the dump truck, and the boom operation lever 70 and the turning operation lever 73 are operated in the opposite directions to the above, a boom lowering signal and a turning signal are input to the controller 32. As a result, the meter-in opening area control unit 35 selects the third control function in the same manner as described above, controls the amount of electricity in the same manner as described above, and increases the boom lowering speed and the turning speed.

The meter-out control section selects the first control function. That is, in this case, since there is no earth and sand in the bucket 48 and the weight of the revolving structure is light and the inertia is small, the energization of the solenoid 31 of the electromagnetic proportional pressure reducing valve 30 is performed so as to increase the meter-out opening area of the reversing switching valve 59. Increase the amount.

The 90-degree loading operation mode is the controller 3
2 is input to the meter-in opening area control unit 35.
9, the maximum current I-1 to the solenoid 31 of the electromagnetic proportional pressure control valve 30, which outputs pressure oil to the meter-in switching valve 3 of the boom switching valve 56, is slightly reduced as shown in FIG. As shown in FIG. 10, the meter-in opening area is slightly reduced to reduce the maximum energization amount I-2 to the solenoid 31 of the electromagnetic proportional pressure control valve 30 that outputs pressure oil to the meter-in switching valve 3 of the turning switching valve 59. Increase the meter-in opening area slightly. That is, the above-mentioned flow distribution ratio is slightly increased. As a result, the boom ascent speed is slightly slower and the turning speed is slightly faster.

When the 135-degree loading operation mode is input to the controller 32, the meter-in opening area control section 35 selects the fifth control function, and the two electromagnetic proportional pressure control valves 30 are selected.
Assuming that the maximum energization amount to the solenoid 31 is the same, the above-mentioned flow distribution ratio is set to 1. As a result, the energization amount of the solenoid 31 of each electromagnetic proportional pressure control valve 30 is determined so that the boom raising speed is medium speed and the turning speed is medium speed.

When the lifting signal from the boom operation lever 70 and the turning signal from the turning operation lever 73 are input to the controller 32 while the 180-degree loading operation mode is input to the controller 32, the meter-in opening area control unit 35 Selects the sixth control function, and reduces the maximum energization amount I-1 of the solenoid 31 of the electromagnetic proportional pressure control valve 30 that outputs pressure oil to the meter-in switching valve 3 of the boom switching valve 56 as shown in FIG. , An electromagnetic proportional pressure control valve 30 that outputs pressure oil to the meter-in switching valve 3 of the turning switching valve 59
The maximum energization amount I-2 to the solenoid 31 is increased as shown in FIG.

As a result, the meter-in opening area of the swing switching valve 59 becomes larger than the meter-in opening area of the boom switching valve 56, and a small amount of pressure oil is supplied to the boom cylinder 45. Since the supply flow rate is large, the boom raising speed is low and the turning speed is high.

Therefore, the upper vehicle body 42 is
The vehicle turns 0 degrees, and the boom 44 rises to a predetermined height during the rotation. The same applies to the case of turning in the opposite direction.

The deep groove loading operation is performed by the boom 44 and the arm 4
6 is pivoted downward to excavate a portion of the traveling body 40 below the ground contact surface with a bucket 48, and then the boom 44 and the arm 46 are excavated.
Is a work mode in which the upper body 42 is swung while swinging upward, and the bucket 48 is moved to the loading position described above. In this case, the meter-in opening area control unit 35
And select the control function as follows: In other words, in this operation, the rising and lowering distances of the boom 44 and the arm 46 are long, so the solenoid of the electromagnetic proportional pressure control valve 30 that supplies pressure oil to the meter-in switching valve 3 of the boom switching valve 56 and the arm switching valve 57 is used. The boom cylinder 45 and the arm cylinder 47 are quickly expanded and contracted by increasing the maximum energization amount to the 31 and the meter-in opening area thereof, and pressurized oil is supplied to the meter-in switching valve 3 of the swing switching valve 59. The maximum energization amount to the solenoid 31 of the electromagnetic proportional pressure control valve 30 is reduced, the meter-in opening area is reduced, and the rotation speed of the turning hydraulic motor 43 is reduced. That is, the supply flow rate Q ₁ to the boom cylinder 45 + the supply flow rate Q ₂ to the arm cylinder 47 and the turning hydraulic motor 43
Distribution ratio (Q ₁ + Q ₂ ) / Q ₃ of the supply flow rate Q _{3 to} the fuel cell is increased.

More specifically, the posture of a working machine such as a boom, an arm or a bucket, that is, the position of the bucket 48 is determined based on the swing angle of the boom 44 and the arm 46 below the detection angle of the boom angle sensor 53 and the arm angle sensor 54. The excavation position (groove depth) is calculated, and the flow rate distribution ratio (Q ₁ + Q) is determined according to the depth of the groove.
₂ ) Select / Q ₃ to set the meter-in opening area of the boom switching valve 56, the arm switching valve 57, and the turning switching 59.

In the above description, the capacity (discharge amount per rotation) of the hydraulic pump 1 may be controlled based on the highest load pressure among the load pressures of the hydraulic actuators. The operation amounts of the respective operation levers may be totalized, and the control may be performed based on the total operation amount.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a controller.

FIG. 3 is a table showing a relationship between an operation amount of an operation lever and a current supply amount.

FIG. 4 is a side view of the hydraulic excavator.

FIG. 5 is a hydraulic circuit diagram of the hydraulic shovel.

FIG. 6 is an explanatory diagram of a controller.

FIG. 7 is a table showing a relationship between an operation amount of an operation lever and an energization amount.

FIG. 8 is a table showing a relationship between an operation amount of an operation lever and an energization amount.

FIG. 9 is a table showing a relationship between an operation amount of an operation lever and a current supply amount.

FIG. 10 is a table showing a relationship between an operation amount of an operation lever and an energization amount.

FIG. 11 is a table showing a relationship between an operation amount of an operation lever and an energization amount.

FIG. 12 is a table showing a relationship between an operation amount of an operation lever and a current supply amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hydraulic pump 3 ... Meter-in switching valve 4 ... Pump port 5 ... 1st actuator port 6 ... 2nd actuator port 10 ... Hydraulic actuator 13 ... Meter-out switching valve 15 ... 1st return port 16 ... 2nd return port 17 ... Tank Port 30 ... Electromagnetic proportional pressure control valve 31 ... Solenoid 32 ... Controller 33 ... Operation lever 34 ... Potentiometer 35 ... Meter-in opening area control unit 36 ... Meter-out opening area control unit 42 ... Upper body 43 ... Hydraulic motor for turning 44 ... Boom 45 ... Boom cylinder 46 ... Arm 47 ... Arm cylinder 48 ... Bucket 49 ... Bucket cylinder 50 ... Left running hydraulic motor 51 ... Right running hydraulic motor 52 ... Slewing angle sensor 53 ... Boom angle sensor 54 ... Arm angle sensor 55 … Bucket angle sensor 56… Switching valve for boom 57 ... Switching valve for arm 58 ... Switching valve for bucket 59 ... Switching valve for turning 60 ... Switching valve for left running 61 ... Switching valve for right running 70 ... Operation lever for boom 71 ... Operation lever for arm 72 ... Bucket operating lever 73 ... Turning operating lever 74 ... Left running operating lever 75 ... Right running operating lever 76 ... Mode switch 77 ... Mode switch 78 ... Mode switch

Claims (3)

[Claims] A hydraulic pump (1) and a hydraulic actuator (1) provided in a discharge circuit of the hydraulic pump (1).
0), the hydraulic pump (1) and the hydraulic actuator (1
0), provided with a meter-in switching valve (3) for controlling the meter-in flow rate according to the differential pressure between the pump pressure and the load pressure, wherein the hydraulic actuator (10) to the tank (14) In the return circuit to the meter-out switching valve (1) for controlling the meter-out flow rate independent of the meter-in switching valve (3)
3) A pressure oil supply device provided with 3). 2. A hydraulic pump (1), a hydraulic actuator provided in a discharge circuit of the hydraulic pump (1) for operating a working machine, and a meter-in flow rate provided between the hydraulic pump (1) and the hydraulic actuator. A meter-in switching valve (3) to be controlled and a meter-out switching valve (13) provided in a return circuit from the hydraulic actuator to the tank (14) to control a meter-out flow rate independently of the meter-in switching valve (3). In the pressure oil supply device provided, the meter-in opening area of the meter-in switching valve (3) is
Means for controlling in accordance with the differential pressure between the pump pressure and the load pressure and the work content; and controlling the meter-out opening area of the meter-out switching valve (13) in accordance with the work content independently of the meter-in switching valve (3). A pressure oil supply device comprising means. 3. The work content is at least one of a work type, an operation amount of an operation lever for outputting a signal for operating a hydraulic actuator, a posture of a work implement, a load pressure of a hydraulic actuator, and the like. 2. The pressure oil supply device according to 2.