WO2015119311A1

WO2015119311A1 - Control valve for construction equipment and control method thereof

Info

Publication number: WO2015119311A1
Application number: PCT/KR2014/001050
Authority: WO
Inventors: 주상규; 강민혁
Original assignee: 볼보 컨스트럭션 이큅먼트 에이비; 주상규; 강민혁
Priority date: 2014-02-07
Filing date: 2014-02-07
Publication date: 2015-08-13

Abstract

Disclosed are a control value for construction equipment for controlling oil flow supplied to a hydraulic actuator from a hydraulic pump by spool switching and a control method thereof. The control valve for construction equipment, according to the present invention, comprises: a valve body having a supply passage and an actuator supply passage formed therein, the supply passage being connected in parallel to a pump passage through which hydraulic oil of a hydraulic pump is supplied and the actuator supply passage being connected to a hydraulic actuator; a spool installed to be switchable in the valve body; and a pilot pressure chamber to which pilot pressure for switching the spool is applied through a pilot port, wherein the spool is switched in a pressing direction of a spool spring when an arbitrary pilot pressure applied to the pilot pressure chamber is lower than a set pressure of the spool spring, maintained in a neutral state when another pilot pressure applied to the pilot pressure chamber is higher than the set pressure of the spool spring, and switched in the opposite direction to the pressing direction of the spool spring when yet another pilot pressure applied to the pilot pressure chamber is higher than the pilot pressure applied in order to maintain the spool in the neutral state.

Description

Control valve for construction machinery and its control method

The present invention relates to a construction machine, and more specifically, to a control valve and a control method for controlling the flow of the flow supplied from the hydraulic pump to the hydraulic actuator by the spool switching.

Control valve for construction machinery according to the prior art shown in Figure 1,

A pump passage 4 through which hydraulic oil of the hydraulic pump 1 is supplied to the valve body 3 of the control valve A in order to control the hydraulic oil flow supplied from the hydraulic pump 1 to the hydraulic actuator 2, Supply passages 5 connected in parallel to the pump passages 4 and

actuator supply passages

6 and 7 connected to the hydraulic actuators 2 are formed.

A check valve C is installed in the passage between the pump passage 4 and the supply passage 5 so as to be openable and openable.

At the time of switching by application of pilot pressure to the

pilot ports

8 and 9, the hydraulic oil of the hydraulic pump 1 is supplied to the hydraulic actuator 2, and at the same time, the hydraulic oil discharged from the hydraulic actuator 2 is supplied to the hydraulic oil tank ( A spool 10 for draining to the valve body 3 is provided in a switchable manner.

According to the above configuration, when a pilot pressure is applied to the pilot port 8, the spool 10 is switched in the right direction in the drawing. By the switching of the spool 10, the supply passage 5 and the one-side actuator supply passage 6 communicate with each other. At this time, the hydraulic oil of the hydraulic pump 1 is supplied to the pump passage 4 to open the check valve (C). Therefore, the hydraulic oil of the hydraulic pump 1 passes through the pump passage 4-the supply passage 5-one actuator supply passage 6 in order and is supplied to the large chamber of the hydraulic actuator 2.

At this time, the hydraulic oil discharged from the small chamber of the hydraulic actuator 2 is returned to the hydraulic oil tank (not shown) through the other actuator supply passage 7-tank passage (11). Therefore, the hydraulic actuator 2 can be extended and driven.

In the conventional control valve A as described above, a separate pilot line is required to apply pilot pressure to the

pilot ports

8 and 9, respectively. Therefore, when several control valves (A) are assembled in the main control valve (MCV), two pilot lines are required for each control valve (A), thus increasing the amount of hydraulic piping used.

On the other hand, when the electromagnetic proportional pressure reducing valve is applied to control the pilot pressure applied to the

pilot ports

8 and 9, the electromagnetic proportional pressure reducing valve is mounted to the

pilot ports

8 and 9, respectively. Due to the increase in the number of parts due to the electromagnetic proportional pressure reducing valve has a problem that the cost cost increases.

Accordingly, an object of the present invention is to provide a control valve for a construction machine and a control method thereof capable of controlling the spool of the control valve in both directions by one electromagnetic proportional pressure reducing valve.

According to the disclosed contents to achieve the above and other objects of the present invention, the valve body is formed with a supply passage connected in parallel to the pump passage is supplied with the hydraulic oil of the hydraulic pump, and an actuator supply passage connected to the hydraulic actuator;

The spool which is internally switchable to the valve body, the spool is pressurized in one direction by the spool spring, and in a neutral state when a pilot pressure exceeding the set set pressure of the spool spring is applied in a direction opposite to the pressing direction of the spool spring. To maintain;

And a pilot pressure chamber formed on one side of the valve body and configured to apply a pilot pressure for switching the spool through a pilot port.

When any pilot pressure applied to the pilot pressure chamber is smaller than the set set pressure of the spool spring, one of the pump passage and the actuator supply passage is communicated, and the other of the actuator supply passage is connected to the tank passage. To switch the spool in the pressing direction of the spool spring,

When the other pilot pressure applied to the pilot pressure chamber is greater than the set set pressure of the spool spring, the spool is maintained in a neutral state to block the pump passage and the actuator supply passage,

If another pilot pressure applied to the pilot pressure chamber is greater than the pilot pressure applied to maintain the spool in a neutral state, the other of the pump passage and the actuator supply passage communicates with one another of the actuator supply passage. Provided is a control valve for a construction machine, characterized in that the spool is switched in a direction opposite to the pressing direction of the spool spring to connect one to the tank passage.

It is installed in the first passage between the pilot port and the pilot pressure chamber, and converts the hydraulic oil flowing through the pilot port into a pilot pressure corresponding to the applied electrical signal to apply the converted pilot pressure to the pilot pressure chamber An electromagnetic proportional pressure reducing valve is provided.

An electric operation lever for applying an electrical signal to the electromagnetic proportional pressure reducing valve is used to switch the spool to a predetermined position.

A stopper installed in a second passage between the pilot port and the pilot pressure chamber, the stopper preventing the neutral of the spool from being released by the elastic force of the spool spring when the equipment is turned off;

And a stopper spring elastically biases to press the stopper that presses the end of the spool to an initial state so that the neutral of the spool is maintained even when the starting of the equipment is turned off.

The elastic force of the stopper spring is greater than the elastic force of the spool spring.

According to the disclosed contents to achieve the above and other objects of the present invention, the valve body is formed with a supply passage connected in parallel to the pump passage is supplied with the hydraulic oil of the hydraulic pump, and an actuator supply passage connected to the hydraulic actuator; A spool switchable on the valve body; In the control method of a control valve for a construction machine comprising: a pilot pressure chamber is formed on one side of the valve body and the pilot pressure for switching the spool is applied through a pilot port:

Release the stopping state of the spool when equipment start-up is on;

When any pilot pressure smaller than the set set pressure of the spool spring for pressing the spool in one direction is applied to the pilot pressure chamber, the spool is pressed in the pressing direction of the spool spring to switch to the first position;

Maintain the spool in a neutral state when another pilot pressure greater than the set set pressure of the spool spring is applied to the pilot pressure chamber;

When another pilot pressure greater than the pilot pressure applied to maintain the spool in the neutral state is applied to the pilot pressure chamber, the spool is pressurized in a direction opposite to the pressing direction of the spool spring to switch to the second position. It provides; a control method for a control valve for a construction machine comprising a.

The pilot pressure applied to the pilot pressure chamber to switch the spool to the first position is 0 to 20 kgf / cm 2, and the pilot pressure applied to the pilot pressure chamber to maintain the spool in a neutral state is 20 kg. f / cm 2, and the pilot pressure applied to the pilot pressure chamber for switching the spool to the second position is 20 to 40 kgf / cm 2.

According to the disclosed contents of the present invention having the above-described configuration, as the spool of the control valve is controlled in both directions by one electromagnetic proportional pressure reducing valve, a pilot line or the like for applying the pilot pressure of the operating lever RCV to the control valve or the like. Even if the electronic proportional pressure reducing valve is applied, the number of parts can be reduced.

1 is a schematic view of a control valve for a construction machine according to the prior art,

2 is a schematic view of a control valve for a construction machine according to the disclosed subject matter;

3 is a view of the spool neutral state of the control valve shown in FIG.

4 is a view of a state in which the spool of the control valve shown in FIG. 2 is switched in one direction;

5 is a view showing a state in which the spool of the control valve shown in FIG. 2 is switched in another direction;

6 is a flowchart of a control valve control method for a construction machine according to the disclosed contents of the present invention.

One; Hydraulic pump

3; Valve body

5; Supply passage

7; Actuator supply passage

9; Pilot port

11; Tank passage

13; Pilot port

15; The first passage

17; Electronic proportional pressure reducing valve

19; Stopper spring

Hereinafter, a control valve for a construction machine and a control method thereof according to the disclosed contents will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic view of a control valve for a construction machine according to the disclosure of the present invention, Figure 3 is a view of the spool neutral state of the control valve shown in Figure 2, Figure 4 is a spool of the control valve shown in Figure 2 5 is a view of a state switched in one direction, Figure 5 is a view of a state in which the spool of the control valve shown in Figure 2 is switched in another direction, Figure 6 is a control valve control method for a construction machine according to the disclosure of the present invention Is a flow chart.

2 to 5, a control valve for a construction machine according to the disclosure of the present invention,

actuator supply passages

6 and 7 connected to the hydraulic actuators 2 are formed.

When switched by the pilot pressure applied through the pilot port 13 to the pilot pressure chamber 12 formed on one side of the valve body 3, the supply passage 5 and the actuator supply passage (6 or 7) Is communicated with the valve body (3).

The spool 10 is pressurized in one direction by the spool spring 18, and the pilot pressure exceeding a preset set pressure of the spool spring 18 is opposite to the pressing direction of the spool spring 18. When applied to the seal 12 will maintain a neutral state.

The pilot pressure chamber 12 communicates with the pilot port 13 through which the hydraulic oil flows through the second passage 14 communicating with the pilot port 13.

An electromagnetic proportional pressure reducing valve 17 for converting the hydraulic oil flowing through the pilot port 13 into a pilot pressure corresponding to an applied electrical signal to apply the converted pilot pressure to the pilot pressure chamber 12 is provided. The first passage 15 between the port 13 and the pilot pressure chamber 12 is provided.

At this time, an electric operation lever (referring to RCV not shown) for applying an electrical signal to the electromagnetic proportional pressure reducing valve 17 may be used to switch the spool to a predetermined position.

A stopper 16 is provided between the pilot port 13 and the pilot pressure chamber 12 to prevent the neutral of the spool 10 from being released by the elastic force of the spool spring 18 when the equipment is turned off. It is installed to be switchable in the second passage (14).

And a stopper spring 19 which elastically biases to press the stopper 16 which presses one end of the spool 10 so as to maintain the neutrality of the spool 10 even when the starting of the equipment is turned off. can do. At this time, the elastic force of the stopper spring 19 is greater than the elastic force of the spool spring 18.

When any pilot pressure (0 to 20 kgf / cm 2) applied to the pilot pressure chamber 12 is smaller than the set set pressure of the spool spring 18, the pump passage 4 and the actuator supply passage ( 6,7) to communicate with the other one of the actuator supply passage (6,7) to the tank passage (11) to switch the spool 10 in the pressing direction of the spool spring (18) Become,

When the other pilot pressure (20 kgf / cm 2) applied to the pilot pressure chamber 12 is greater than the set set pressure of the spool spring 18, the pump passage 4 and the actuator supply passages 6, 7. ) To keep the spool 10 in a neutral state,

Another pilot pressure (20-40 kgf / cm 2) applied to the pilot pressure chamber 12 is greater than the pilot pressure (20 kgf / cm 2) applied to keep the spool 10 in a neutral state. In this case, the spool (s) for communicating the other of the pump passage (4) and the actuator supply passage (6,7) and any one of the actuator supply passage (6,7) to the tank passage (11) 10) is switched in the direction opposite to the pressing direction of the spool spring (18).

In the figure, reference numeral a denotes a center bypass flow path for returning the working oil in the pump passage 4 to the working oil tank when the spool 10 is neutral.

According to the above-described configuration, as shown in Figure 2, the stopper 16 is subjected to the elastic force of the stopper spring 19 in the state that the start of the equipment (OFF) OFF. At this time, the elastic force of the stopper spring 19 to elastically support the stopper 16 is relatively greater than the elastic force of the spool spring 18 to elastically support the spool 10.

Therefore, in the state that the start of the equipment (OFF) (OFF), the end of the spool 10 by the stopper 16 is pressed, so that the spool 10 can maintain a neutral state.

As shown in FIGS. 3 and 6, in the state in which the start of the equipment is turned on (S10), when the hydraulic oil (40 kgf / cm 2) is supplied to the pilot port 13, the first The stopper 16 provided in the passage 15 is pressurized to switch to the left in the drawing. As a result, the stopper 16 may be disengaged from one end of the spool 10 (that the stopper 16 is disengaged from the stroke section of the spool 10 so that the stopping state of the spool 10 is released). (S20).

At this time, when operating the electric operation lever (not shown), an electrical signal corresponding to the operation amount is applied to the electromagnetic proportional pressure reducing valve 17. Therefore, the electromagnetic proportional pressure reducing valve 17 reduces the hydraulic oil flowing through the pilot port 13 and introduced into the second passage 14 to a predetermined set pressure (for example, 20 kgf / cm 2). The reduced pilot pressure is applied to the pilot pressure chamber 12. At this time, if the secondary pilot pressure applied to the pilot pressure chamber 12 is greater than the set pressure of the spool spring 18, the process proceeds to S40, and the secondary pilot pressure applied to the pilot pressure chamber 12 is the spool spring ( If it is smaller than the set pressure of 18), proceed to S20.

As in S40, when the secondary pilot pressure applied to the pilot pressure chamber 12 is greater than the set pressure of the spool spring 18, the spool 10 can maintain a neutral state (S40).

On the other hand, the case where the hydraulic actuator is extended and driven will be described.

As shown in FIGS. 4 and 6, an electric signal corresponding to the manipulated amount is applied to the electromagnetic proportional pressure reducing valve 17 as the electric operation lever is operated to extend and drive the hydraulic actuator 2. As a result, the electromagnetic proportional pressure reducing valve 17 converts the hydraulic oil flowing into the second passage 14 into the secondary pilot pressure and converts the secondary pilot pressure (eg, 20 to 20) into the pilot pressure chamber 12. 40 kgf / cm 2) is applied. At this time, since the secondary pilot pressure applied to the pilot pressure chamber 12 exceeds the elastic force of the spool spring 18 supporting the spool 10, the spool 10 is switched in the right direction in the drawing ( The spool 10 is switched to the second position) (S60).

By the switching of the spool 10, the supply passage 5 and the one-side actuator supply passage 6 communicate with each other. At this time, the check valve (C) is opened by the hydraulic oil supplied from the hydraulic pump (1) to the pump passage (4). Therefore, the hydraulic oil of the hydraulic pump 1 passes through the pump passage 4-the supply passage 5-the actuator supply passage 6 and is supplied to the large chamber of the hydraulic actuator 2. At this time, the hydraulic oil discharged from the small chamber of the hydraulic actuator 2 is returned to the hydraulic oil tank (not shown) through the actuator supply passage 7-tank passage (11).

Thus, the hydraulic actuator 2 can be extended and driven.

On the other hand, a case where the hydraulic actuator is driven to shrink.

As shown in Figs. 5 and 6, an electric signal corresponding to the operation amount is applied to the electromagnetic proportional pressure reducing valve 17 as the electric operation lever is operated to shrink and drive the hydraulic actuator 2. Accordingly, the electromagnetic proportional pressure reducing valve 17 converts the hydraulic oil flowing into the second passage 14 into the secondary pilot pressure and converts the secondary pilot pressure (eg, 0 to 0) into the pilot pressure chamber 12. 20 kgf / cm 2) is applied. At this time, since the secondary pilot pressure applied to the pilot pressure chamber 12 is smaller than the elastic force of the spool spring 18 supporting the spool 10, the spool 10 is switched to the left in the drawing (spool). (10) is switched to the first position) (S70).

By switching of the spool 10, the supply passage 5 and the other actuator supply passage 7 communicate with each other. At this time, the check valve (C) is opened by the hydraulic oil supplied from the hydraulic pump (1) to the pump passage (4). Therefore, the hydraulic oil of the hydraulic pump 1 passes through the pump passage 4-the supply passage 5-the other actuator supply passage 7 in order and is supplied to the small chamber of the hydraulic actuator 2. At this time, the hydraulic oil discharged from the large chamber of the hydraulic actuator 2 is returned to the hydraulic oil tank (not shown) through the one-side actuator supply passage 6-tank passage (11).

Therefore, it is possible to shrink-drive the hydraulic actuator 2.

Herein, while the present invention has been described with reference to the preferred embodiments, those skilled in the art will variously modify the present invention without departing from the spirit and scope of the invention as set forth in the claims below. And can be changed.

According to the present invention having the above-described configuration, by controlling the spool of the control valve in both directions by one electromagnetic proportional pressure reducing valve there is an effect that can reduce the number of parts to reduce the cost cost.

Claims

A valve body having a supply passage connected in parallel to a pump passage to which hydraulic oil of the hydraulic pump is supplied, and an actuator supply passage connected to the hydraulic actuator;

The spool which is internally switchable to the valve body, the spool is pressurized in one direction by the spool spring, and in a neutral state when a pilot pressure exceeding the set set pressure of the spool spring is applied in a direction opposite to the pressing direction of the spool spring. To maintain;

And a pilot pressure chamber formed on one side of the valve body and configured to apply a pilot pressure for switching the spool through a pilot port.

When any pilot pressure applied to the pilot pressure chamber is smaller than the set set pressure of the spool spring, one of the pump passage and the actuator supply passage is communicated, and the other of the actuator supply passage is connected to the tank passage. To switch the spool in the pressing direction of the spool spring,

When the other pilot pressure applied to the pilot pressure chamber is greater than the set set pressure of the spool spring, the spool is maintained in a neutral state to block the pump passage and the actuator supply passage,

If another pilot pressure applied to the pilot pressure chamber is greater than the pilot pressure applied to maintain the spool in a neutral state, the other of the pump passage and the actuator supply passage communicates with one another of the actuator supply passage. And the spool is switched in a direction opposite to the pressing direction of the spool spring so as to communicate one with the tank passage.
The method of claim 1,

It is installed in the first passage between the pilot port and the pilot pressure chamber, and converts the hydraulic oil flowing through the pilot port into a pilot pressure corresponding to the applied electrical signal to apply the converted pilot pressure to the pilot pressure chamber A control valve for a construction machine, characterized by having an electromagnetic proportional pressure reducing valve.
The method of claim 2,

An electric operation lever for applying an electrical signal to the electromagnetic proportional pressure reducing valve is used to switch the spool to a predetermined position.
The method of claim 1,

A stopper installed in a second passage between the pilot port and the pilot pressure chamber, the stopper preventing the neutral of the spool from being released by the elastic force of the spool spring when the equipment is turned off;

And a stopper spring configured to elastically bias the pressing of the stopper that presses the end of the spool to maintain the neutral of the spool even when the starting of the equipment is turned off.
The method of claim 4, wherein

The elastic force of the stopper spring is greater than the elastic force of the spool spring control valve for a construction machine.
A valve body having a supply passage connected in parallel to a pump passage to which hydraulic oil of the hydraulic pump is supplied, and an actuator supply passage connected to the hydraulic actuator; A spool switchable on the valve body; In the control method of a control valve for a construction machine comprising: a pilot pressure chamber is formed on one side of the valve body and the pilot pressure for switching the spool is applied through a pilot port:

Release the stopping state of the spool when equipment start-up is on;

When any pilot pressure smaller than the set set pressure of the spool spring for pressing the spool in one direction is applied to the pilot pressure chamber, the spool is pressed in the pressing direction of the spool spring to switch to the first position;

When another pilot pressure greater than the set set pressure of the spool spring is applied to the pilot pressure chamber, the spool is kept in a neutral state;

When another pilot pressure greater than the pilot pressure applied to maintain the spool in the neutral state is applied to the pilot pressure chamber, the spool is pressurized in a direction opposite to the pressing direction of the spool spring to switch to the second position. Control method of a control valve for a construction machine, characterized in that.
The method of claim 6,

The pilot pressure applied to the pilot pressure chamber to switch the spool to the first position is 0 to 20 kgf / cm 2, and the pilot pressure applied to the pilot pressure chamber to maintain the spool in a neutral state is 20 kg. and a pilot pressure applied to the pilot pressure chamber for switching the spool to the second position is 20 to 40 kgf / cm 2.