JP2551344Y2 - Hydraulic circuit of construction machinery - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit of a construction machine, and more particularly to a hydraulic circuit of a construction machine having a so-called energy saving circuit.

[0002]

2. Description of the Related Art In a construction machine, an actuator is driven through a pilot hydraulic control valve to control a piston.
Lot hydraulic control control valve with pilot hydraulic pressure
When the operating lever of the remote control valve to be controlled is neutral, minimize the discharge of the variable displacement pump,
The maximum pressure of the pilot hydraulic pressure generated when the operating lever is operated is detected by the high pressure selection valve, by directing the highest pressure of the pilot hydraulic pressure to the variable displacement pump, the pilot pressure control for increasing the discharge rate of the variable displacement pump Some have circuits. This pilot hydraulic control circuit
Of the variable displacement pump corresponding to the operation of the actuator
Since the discharge amount is controlled, it is called an energy saving circuit.

[0003] For example, in a pile driver, a pilot hydraulic
Actuator separate from the actuator driven by the control circuit
The hydraulic hammer, which is the
Non-pilot hydraulic control circuit driven by troll valve
May be installed together with the pilot hydraulic control circuit.
The pilot hydraulic control circuit and the non-pilot hydraulic control circuit
Choose a road and use one or the other, depending on the task
I have.

[0004]

[Problem to be solved by the invention] However, in this case
When using the non-pilot hydraulic control circuit,
Controls the displacement of the variable displacement pump in response to the operation of the hammer
Non-pilot hydraulic control
Even when the operating lever of the lube is in the neutral state, it is reconfigured to maximize the discharge of the
The pilot hydraulic control circuit was cut.

Accordingly, the present invention provides a pilot hydraulic control circuit.
And an on-site and a non-pilot hydraulic control circuit, a non-pilot
It is an object of the present invention to provide a hydraulic circuit for a construction machine that can control the discharge amount of a variable displacement pump even when a hydraulic control circuit is selectively used .

[0006]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides an actuation line for a variable displacement pump.
Hydraulic control valve for pilot drive
A pilot hydraulic control circuit having a blanking, the actuator
Non-pilot oil that drives another actuator
And a non-pilot hydraulic control circuit having a pressure control the control valve, the pilot hydraulic control circuit, each path
The variable displacement pump detects the maximum pressure of the pilot oil pressure
A high-pressure selection valve for controlling the discharge amount of
And the non-pilot hydraulic control circuit
In the hydraulic circuit for a construction machine which selectively used, the ejection
Control line from the outgoing line
A center bypass line that passes through the
Connect the non-pilot hydraulic control circuit to the bypass line
The non-pilot hydraulic control circuit includes the center bypass.
Sequence bar to open and close the pass line tank discharge line
And a sequence valve control line.
And a switching valve that operates through the
Branch connection of the self-pressure extraction line to the control valve control line
Discharge from the high pressure selection valve to the variable displacement pump.
In the output control line, the hydraulic pressure of the self-pressure extraction line
An operating pilot hydraulic switching valve is provided and the pilot
The pilot switching from the pilot hydraulic source
Connect the hydraulic pressure supply line and
By raising the pressure, the pilot hydraulic switching valve is set to the high position.
The communication between the pressure selection valve and the variable displacement pump
Switch to the communication between the cut hydraulic pressure source and the variable displacement pump.
It is characterized in that that.

[0007]

[Operation] According to the above configuration, the non-pilot hydraulic control circuit
If using road, pilot hydraulic control
Set the valve to neutral and operate the switching valve to sequence
When the valve is closed, the use of the non-pilot hydraulic control circuit
And the non-pilot hydraulic control circuit boosts the pressure
As a result, the pressure in the self-pressure extracting line rises, thereby switching the pilot hydraulic pressure switching valve so that the line between the pilot hydraulic pressure source and the variable displacement pump communicates with each other. Actuator driven by non-pilot hydraulic control circuit
It increases in response to the operation of the heater .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a hydraulic circuit showing a first embodiment of the present invention.
For example, it is used for a pile driver. This hydraulic circuit
1 is a first variable displacement pump 2 and a second variable displacement pump 3
And it has a door. Discharge line 4 of first variable displacement pump 2
The pilot hydraulic control control valves 5 and 6
A first pilot hydraulic control circuit 7
And each pilot hydraulic control control valve 5, 6
For example, a pair of left and right first actuators (not shown)
) Are respectively driven.

The discharge line 8 of the second variable displacement pump 3 is provided with pilot hydraulic control valves 9 and 1.
A second pilot hydraulic control circuit 11 having
And each pilot hydraulic control control valve 9,
10, a pair of left and right second actuators
(Not shown) are respectively driven.

The pilot hydraulic control valves 5, 6, 9 and 10 are controlled by remote control valves 12, 13, 14 and 15, respectively.
Each remote control valve 12, 13, 14, 15
And each pilot hydraulic control control valve 5, 6,
The pressure oil supplied from the pilot hydraulic pressure source 16 is supplied between the remote control valves 12, 13,
A pilot hydraulic circuit 17 controlled by 14 and 15 is provided.

The first and second pilot hydraulic control circuits 7,
The pilot hydraulic circuit 17 associated with 11 is provided with a high-pressure selection valve 18,
Each remote control valve 12, 13, 14, 15
By detecting the maximum pressure of the pilot hydraulic pressure generated by the above operation, and guiding the maximum pressure of the pilot hydraulic pressure to the first variable displacement pump 2 and the second variable displacement pump 3, the first variable displacement pump 2 and the second variable displacement The discharge amount of the pump 3 is controlled.

The discharge line 4 of the first variable displacement pump 2 is provided with a center bypass line 19 passing through pilot hydraulic control valves 5 and 6 .
A non-pilot hydraulic system is connected to the center bypass line 19.
The control circuit 20 is connected. This non-pilot hydraulic system
The control circuit 20 is, for example, a hydraulic
It drives a hammer (not shown).
The pilot hydraulic control circuits 7 and 11 are used selectively.
You.

[0014] The non-pilot hydraulic control circuit 20, Se
Open the tank discharge line 21 of the intermediate bypass line 19
A sequence valve 22 to be closed;
2 via the sequence valve control line 23
A switching valve 24 is provided to control the sequence valve.
The self-pressure extraction line 25 is branched and connected to the line 23,
Non-pyro into the C port at the end of the bypass line 19
Via a hydraulic control valve (not shown)
The third actuator, the hydraulic hammer, is connected
You.

The switching valve 24 is operated by an operation system independent of the pilot hydraulic circuit 17.
Ru is actuated by the operation lever or the like through a link mechanism.
When the switching valve 24 is open, the center bypass line
Pressure oil from the in 19 via the sequence valve 22
To the tank from the T port of the tank discharge line 21
ing. Then, the switching valve 24 is switched and closed.
Accordingly, the pressure oil from the C port is supplied to the hydraulic hammer is closed shea Kensubarubu 22.

[0016] The high pressure selected from the valve 18 the first and second
In the discharge amount control line 26 to the variable displacement pumps 2 and 3 ,
Pilot operated by hydraulic pressure of self-pressure extraction line 25
A hydraulic pressure switching valve 27 is provided to switch the pilot hydraulic pressure.
A valve from the pilot hydraulic source 16
G hydraulic pressure supply line 28 is connected.

The pilot hydraulic switching valve 27 is
Depending on the step-up of his own takeout line 25, the high-pressure selection valve
18 and communication between the first and second variable displacement pumps 2 and 3 are blocked.
The pilot hydraulic pressure source 16 and the first and second variable displacements
The operation is switched to the communication with the pumps 2 and 3.

With such a configuration, the non-pyro
When the oil pressure control circuit 20 is used, the pilot oil
Neutralize pressure control control valves 5, 6, 9, and 10
By operating the switching valve 24, the sequence valve 22
When closed, use of the non-pilot hydraulic control circuit 20 is reduced.
Pressure oil is supplied to the hydraulic hammer from the C port.
As a result, the non-pilot hydraulic control circuit 20
Then, the self-pressure extracting line 25 is boosted,
The pilot hydraulic pressure switching valve 27 is switched
G hydraulic pressure source 16 and first and second variable displacement pumps 2 and 3
Communicate.

As a result, the pilot hydraulic pressure is guided to the first and second variable displacement pumps 2 and 3, and the discharge amounts of the first and second variable displacement pumps 2 and 3 are driven by the non-pilot hydraulic control circuit 20 . Increases in response to the operation of the hydraulic hammer . Therefore, even if the non-pilot hydraulic control circuit 20 that is not controlled by the pilot hydraulic pressure is provided,
Controls the discharge rate of the variable displacement pumps 2 and 3 and provides a hydraulic circuit
1 can be an energy-saving circuit.

FIG. 2 shows a second embodiment of the present invention.
Then, the pressure switch 30 is connected to the self- pressure extracting line 25.
The pressure switch 30 and the solenoid type
With the same configuration as in the first embodiment except that an electric circuit 32 is connected between the pilot pressure switching valve 31 and the pilot pressure switching valve 31, the self-pressure extracting line 25 is switched by switching the switching valve 24.
When the pressure is increased, the pressure switch 30 is actuated to switch the solenoid type pilot hydraulic pressure switching valve 31 to communicate the pilot hydraulic pressure source 16 with the first and second variable displacement pumps 2 and 3, and the first and second variable displacement pumps 2 and 3 To increase the discharge amounts of the first and second variable displacement pumps 2 and 3 as in the first embodiment .

In each of the above embodiments, the hydraulic circuit of the pile driver has been described. However, the present invention is also applicable to construction machines having a hydraulic circuit of a crane.

[0022]

[Effects of the Invention] As described above, the present invention provides a pump for driving an actuator in a discharge line of a variable displacement pump.
A pilot hydraulic control circuit having a lot hydraulic control control valve, and an actuator separate from the actuator.
Non-pilot hydraulic control bar to drive eta
And a non-pilot hydraulic control circuit having a lube, pies
The maximum pressure of each pilot hydraulic pressure is applied to the lot hydraulic control circuit.
High pressure selection bar that detects and controls the discharge rate of the variable displacement pump
A pilot oil pressure control circuit and non-pilot oil
In the hydraulic circuit of construction machinery that selectively uses the pressure control circuit, the pilot hydraulic control
A center bypass line that passes through the
Non-pilot hydraulic control circuit connected to the bypass line
The non-pilot hydraulic control circuit has a center bypass
Sequence valve that opens and closes the line tank discharge line
And the sequence valve is connected to a sequence valve control line.
And a switching valve that operates through the
Branch connection of the self-pressure extraction line to the
Discharge rate control line from selection valve to variable displacement pump
The pilot operated by the hydraulic pressure of the self-pressure extraction line
A hydraulic switching valve, and the pilot hydraulic switching valve
The pilot hydraulic supply line from the pilot hydraulic source
And the pressure rise of the self-pressure extraction line
High pressure selector valve and variable displacement pump
Communication between the pilot hydraulic power source and the variable displacement pump.
Switching operation, so that non-pilot oil
When using a pressure control circuit, the pilot hydraulic control
Set the troll valve to neutral and operate the switching valve to
Non-pilot hydraulic control when sequence valve is closed
Circuit can be used and the non-pilot hydraulic control circuit
By increasing the pressure, the self-pressure extraction line
The pilot hydraulic pressure switching valve is switched, and the line between the pilot hydraulic pressure source and the variable displacement pump communicates. Is
Increases in response to actuation of the actuator .

Therefore, even if a non-pilot hydraulic control circuit which is not controlled by the pilot hydraulic pressure is provided, the discharge amount of the variable displacement pump can be controlled, and the entire hydraulic circuit can be an energy saving circuit. In addition, the non-pilot hydraulic control circuit
Provide a sequence valve and a switching valve on the
The pilot oil is increased by increasing the self-pressure of the lot hydraulic control circuit.
Since the pressure switching valve is switched, use a valve with a simple structure
The discharge amount control circuit can be used. Also non-pie
Lot of variable displacement pump by self pressure of hydraulic control circuit
Responsiveness is good because the discharge amount is controlled.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram showing a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic circuit, 2 ... 1st variable displacement pump, 3 ... 2nd variable displacement pump, 4 ... Discharge line of 1st variable displacement pump,
5, 6, 9, 10 ... pilot hydraulic pressure control control valve, 7, 11 ... pilot hydraulic pressure control circuit, 12, 1
3, 14, 15, ... remote control valve, 16 ...
Pilot hydraulic source, 17 ... Pilot hydraulic circuit, 18 ...
High pressure selection valve, 19 ... Center bypass line, 20
... non-pilot hydraulic control circuit, 21 ... tank discharge line
, 22 ... sequence valve, 23 ... sequence valve
Control line, 24: Switching valve, 25: Self pressure extraction line
In, 26 ... Discharge amount control line, 27 ... Pilot oil pressure
Switching valve, 28 ... pilot hydraulic supply line, 30 ...
Pressure switch, 31 ... Solenoid type pilot oil
Pressure switching valve, 32 ... electric circuit

Claims (1)

(57) [Scope of request for utility model registration] An activator is provided in a discharge line of a variable displacement pump.
Hydraulic control valve for pilot drive
A pilot hydraulic control circuit having a blanking, the actuator
Non-pilot oil that drives another actuator
And a non-pilot hydraulic control circuit having a pressure control the control valve, the pilot hydraulic control circuit, each path
The variable displacement pump detects the maximum pressure of the pilot oil pressure
A high-pressure selection valve for controlling the discharge amount of
And the non-pilot hydraulic control circuit
In the hydraulic circuit for a construction machine which selectively used, the ejection
Control line from the outgoing line
A center bypass line that passes through the
Connect the non-pilot hydraulic control circuit to the bypass line
The non-pilot hydraulic control circuit includes the center bypass.
Sequence bar to open and close the pass line tank discharge line
And a sequence valve control line.
And a switching valve that operates through the
Branch connection of the self-pressure extraction line to the control valve control line
Discharge from the high pressure selection valve to the variable displacement pump.
In the output control line, the hydraulic pressure of the self-pressure extraction line
An operating pilot hydraulic switching valve is provided and the pilot
The pilot switching from the pilot hydraulic source
Connect the hydraulic pressure supply line and
By raising the pressure, the pilot hydraulic switching valve is set to the high position.
The communication between the pressure selection valve and the variable displacement pump
Switch to the communication between the cut hydraulic pressure source and the variable displacement pump.
The hydraulic circuit for a construction machine, characterized in that that.