KR20200047934A - Working fluid take out hydraulic circuit for work machine driving - Google Patents

Abstract

Disclosed is a working fluid take-off hydraulic circuit for the operation of an external operation machine, capable of preventing a cylinder from sagging or floating due to an oil leak from a hydraulic take-off valve by using only one single check valve. The working fluid take-off hydraulic circuit includes: an oil supply line supplying working fluids; a first oil discharge line moving the working fluids when a valve is neutral; a second oil discharge line discharging the working fluids supplied through the oil supply line and operating an actuator; a hydraulic take-off valve unit connected to the oil supply line and the second oil discharge line and comprising at least two hydraulic take-off valves connected to each other through the first oil discharge line; at least two actuators connected to a take-off port of each of the hydraulic take-off valves of the hydraulic take-off valve unit through a cylinder line such that the working fluids can flow; and a check valve installed on a discharge side of the second oil discharge line and connected to an input side of the oil supply line through a working pressure supply line.

Description

Hydraulic oil extraction hydraulic circuit for driving external work equipment {WORKING FLUID TAKE OUT HYDRAULIC CIRCUIT FOR WORK MACHINE DRIVING}

The present invention relates to a hydraulic circuit for hydraulic oil extraction applied to a tractor, and in particular, as a power source for operating a working machine attached to the rear of a tractor, hydraulic oil for driving an external working machine to allow the working oil inside the tractor to be taken out and supplied to the working machine. It is related to a take-out hydraulic circuit.

 A work vehicle called a 'tractor' has an advantageous structure and characteristics in carrying out various tasks depending on the purpose by attaching a work machine to the hitch of the aircraft rear end. For example, by attaching a work machine such as a rake, a rotor, a plow, or a harrow to the hitch, various farming operations such as tillage, excavation and pest control, pumping and threshing can be performed. Can be.

The hitch is raised and lowered by the expansion and contraction of the lifting cylinder according to the flow control of the hydraulic oil (working fluid) by the hydraulic control valve operated by the output signal of the controller in response to the operation of the lever around the control unit around the tractor driver's seat. The height of the working machine can be adjusted.

At the rear of the tractor, a hydraulic valve unit for extracting hydraulic oil is provided to extract the hydraulic oil inside the tractor and supply it to the working machine as a power source for operating the working machine. When connecting the working machine, the hydraulic port of the hydraulic valve unit and the actuator of the working machine are connected with a hydraulic cable. In connection with each other, the hydraulic oil of the tractor main body is supplied to the working machine so that the working machine can be operated.

The hydraulic valve unit applied to the tractor for taking out the hydraulic oil is a hydraulic valve that regulates the flow of oil by switching the moving path of the hydraulic oil sent from the hydraulic pump, and as shown in FIG. 1, a plurality of hydraulic outlet valves 100 are stacked. It is configured to be connected to each other to enable fluid flow.

Due to the nature of the hydraulic valve, an oil leak inevitably occurs, and the oil leak causes a sagging or lifting phenomenon of a cylinder connected to each hydraulic outlet valve, which causes serious problems during work or driving.

As a solution to the oil leak problem, a method of applying a check valve 200 for each valve as in FIG. 1 has been proposed, but when a check valve is applied for each valve, the cost increases in proportion to the number of valves (hydraulic outlet valves). Therefore, it is difficult to secure competitiveness in the economic aspect, and as the number of check valves increases, there is a problem in that the device configuration becomes complicated.

Japanese Patent Publication No. 2007-016483 (published on January 25, 2007)

The technical problem to be solved by the present invention is to provide a hydraulic oil extraction hydraulic circuit for driving an external working machine that can prevent the sagging or lifting of a cylinder according to a hydraulic leak valve oil leak using only one check valve.

According to an embodiment of the present invention as a solution to the problem,

An oil supply line to which hydraulic oil is supplied;

A first drain line through which hydraulic oil flows when the valve is neutral;

A second exhaust line through which the operating oil supplied through the oil supply line and driving the actuator is discharged;

A hydraulic outlet valve unit composed of two or more hydraulic outlet valves connected to the oil supply line and the second exhaust line and interconnected through the first exhaust line;

Two or more actuators connected in a cylinder line to allow hydraulic fluid to flow to and from the outlet side of each hydraulic outlet valve constituting the hydraulic outlet valve unit; And

It is installed on the discharge side of the second oil supply line and a check valve connected to the operating pressure supply line to the input side of the oil supply line; provides a hydraulic circuit for operating oil extraction for driving an external working machine comprising a.

Here, the check valve is operated at a pilot pressure of the oil supply line, which is transmitted through the working pressure supply line when one of the two or more hydraulic outlet valves is switched to the actuator operating side. When it is opened, and when all of the hydraulic outlet valves are switched to the neutral side, it may be configured to be restored in a direction to close the discharge side flow path of the second exhaust line by the restoring force of the inner spring.

Preferably, the check valve may be a pressure check valve in which a pressure chamber communicating with the operating pressure supply line is formed.

In this case, when the pilot pressure greater than the reaction force of the inner spring is applied to the pressure chamber, the check valve is moved in the axial direction so that the input side and output side flow paths of the valve body are connected to the hydraulic fluid by the internal flow path of the spool. It can be configured to be.

In addition, the two or more hydraulic outlet valves may be connected in parallel to the oil supply line and the second oil discharge line, and may be installed in series on the first oil discharge line.

According to the hydraulic oil extraction hydraulic circuit according to an embodiment of the present invention, a simple change of the position of a part of the hydraulic line and the position of the check valve causes the cylinder to sag due to the oil leak of the hydraulic circuit in the neutral state of the valve even with only one check valve. Alternatively, a hydraulic circuit that can effectively prevent lifting can be constructed.

That is, a single check valve is applied to the discharge side of the second drain line that returns the oil to the oil tank by joining the hydraulic oil that drives each actuator, and the hydraulic line is operated so that the check valve can be operated according to the pressure acting on the oil supply line. It is possible to effectively prevent oil leakage in the circuit by simple configuration, and it is a conventional problem with low cost and simple hydraulic circuit configuration (increased cost and complicated hydraulic circuit by using multiple check valves to solve oil leakage) Can solve it.

1 is a hydraulic circuit diagram of hydraulic oil extraction for driving an external working machine according to the prior art.
Figure 2 is a hydraulic circuit for hydraulic oil extraction for driving an external work machine according to an embodiment of the present invention.
3 is a detailed view of the 'I' part in which the check valve is arranged in FIG. 2;
4 to 6 is an operational state diagram of the present invention.

Hereinafter, a preferred embodiment of the present invention will be described in detail.

Terms used in the specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, or that one or more other features or It should be understood that the presence or addition possibilities of numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

Further, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components.

In addition, terms such as “… unit”, “… unit”, and “… module” described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. Can be.

In the description with reference to the accompanying drawings, the same reference numerals will be assigned to the same components, and redundant description thereof will be omitted. In the following description, when it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

2 is a hydraulic circuit diagram of a hydraulic circuit for lifting and floating a work machine for a work vehicle according to an embodiment of the present invention.

Referring to FIG. 2, the hydraulic circuit according to the present invention is a hydraulic oil extraction hydraulic circuit applied to the hydraulic oil extraction side of the tractor rear end so that hydraulic oil inside the tractor can be used as a power source for operating a work machine attached to the tractor rear end. , A first drain line, a second drain line, a hydraulic outlet valve unit, an actuator, and a check valve.

The hydraulic outlet valve unit is connected to a hydraulic pump that generates and supplies hydraulic pressure through the oil supply line. The hydraulic take-off valve unit is composed of two or more hydraulic take-off valves of a stacked type. Each hydraulic outlet valve is connected to form a parallel arrangement between the oil supply line and the second oil discharge line, and is coupled to form a series connection with each other through a first oil discharge line.

Each hydraulic outlet valve regulates the flow of hydraulic oil that the hydraulic pump delivers at a predetermined pressure according to an input of an operation signal from the outside. Specifically, the internal flow path is changed according to an operation signal input from the outside to control the operation or stop of the actuator, or the hydraulic oil supplied through the oil supply line is to be returned to the oil tank side through the first oil supply line as it is. Make it possible.

Each hydraulic take-off valve is a solenoid type that is switched and driven by the input of an electric signal from the outside or a manual type (MANUAL TYPE) direction change valve that controls the flow of hydraulic oil by moving the spool in the axial direction with an operating lever. Can be Preferably, it may be a 6PORT 3WAY valve having one input port (P) and one drain port (R) and two output ports (A, B) and neutral ports (C1, C2).

According to the position of the internal spool (SPOOL) according to the input of the operating signal (or operating force), the hydraulic outlet valve is supplied with hydraulic fluid in the direction of extending the actuator, for example, hydraulic fluid is supplied in the direction of contracting the hydraulic cylinder, Alternatively, the position may be controlled for a total of three directions, such as neutral position switching to allow the supplied hydraulic oil to be drained through the first drain line as it is.

When one of the plurality of hydraulic outlet valves is switched to the actuator extension side, the hydraulic oil supplied through the oil supply line moves through the P port and A port of the hydraulic outlet valve to the extension side hydraulic chamber of the actuator controlled by the hydraulic outlet valve. The hydraulic oil of the opposite hydraulic chamber is drained to the oil tank side through the second drain line through the B port and the R port.

Conversely, when one of the plurality of hydraulic outlet valves is switched to the actuator contraction side, the hydraulic oil supplied through the oil supply line passes through the P port and the B port of the hydraulic outlet valve and the extension side hydraulic pressure of the actuator controlled by the hydraulic outlet valve. It is moved to the seal, and the hydraulic oil of the opposite hydraulic chamber is drained to the oil tank through the second drain line through the A port and the R port.

The refueling line connected to the hydraulic pump may be configured to be branched to the intermediate intermediate hydraulic take-off valve so that the hydraulic oil can be supplied to each hydraulic take-off valve individually, and the first drainage connecting each hydraulic take-off valve in series. The line may be configured to be connected to the oil supply line and to continuously connect the neutral ports of each hydraulic outlet valve in a straight line.

As described above, when the hydraulic outlet valve is operated on the actuator operation (cylinder rise or fall) side, the hydraulic oil supplied to the hydraulic outlet valve through the oil supply line is supplied to the actuator controlled by the hydraulic outlet valve through the cylinder line, When all hydraulic outlet valves are operated on the neutral side, the hydraulic oil supplied to the oil supply line is drained into the oil tank as it is through the first oil drain line.

The second oil drain line forms a hydraulic movement path through which the hydraulic oil discharged from the hydraulic chamber opposite to the operating direction when the actuator is operated can be drained to the oil tank side. Specifically, when one of the plurality of hydraulic outlet valves is operated on the actuator operating side, it guides the oil tank side movement of the hydraulic oil exiting the hydraulic chamber opposite to the operating direction of the actuator under the control of the operated hydraulic outlet valve.

The second oil drain line includes an individual oil drain line and an individual oil drain line extending from the drain port (R port) of each oil hydraulic drain valve so that the hydraulic oil individually drained from each hydraulic oil drain valve can be joined and drained to the oil tank side. It may be composed of a main oil line connected to one, wherein the discharge end of the main oil line is connected to the discharge side of the first oil line.

The actuator is connected in a cylinder line to enable hydraulic fluid flow to the outlet side ports (A and B ports) of each hydraulic outlet valve constituting the hydraulic outlet valve unit. At this time, the actuator may be a hydraulic cylinder that is telescopically driven by hydraulic oil. Preferably, it may be a known double acting cylinder in which two hydraulic chambers are opposed to each other with an inner piston as a boundary.

As illustrated in the drawing, the hydraulic cylinder applied to the actuator is not limited to three. That is, it is of course possible to be composed of three or more, and in this case, it is natural that the hydraulic outlet valve unit should be provided with hydraulic outlet valves in the number corresponding to the hydraulic cylinder.

The check valve is installed on the discharge side of the second drain line just before the second drain line joins the first drain line. The check valve may be configured to open and close the flow path formed by the second oil drain line to control the movement of the hydraulic oil, but is connected to the input side of the oil supply line with an operating pressure supply line to open the flow path with pilot pressure acting on the oil supply line. have.

3 is a detailed view of a 'I' part in which the check valve is installed in FIG. 2.

Referring to FIG. 3, the check valve 40 is operated at the pilot pressure of the oil supply line transmitted through the operating pressure supply line when one of the hydraulic outlet valves is switched to the actuator operating side, and the second oil drain line It is restored in the direction of opening the discharge side flow path of, and closing the discharge side flow path of the second exhaust line by the restoring force of the inner spring when the hydraulic outlet valves are all switched to the neutral side.

The check valve 40 may be a pressure check valve 40 having a hydraulic chamber 401 communicating with the working pressure supply line S. Specifically, when a pilot pressure greater than the spring 404 reaction force acts on the hydraulic chamber 401 through the operating pressure supply line S, the spool 402 is moved in the axial direction so that the flow path formed in the spool 402 is a valve. It may be configured to connect the input side and the output side of the body 400 so as to be able to move the hydraulic fluid.

Depending on the switching state of the valve of the hydraulic take-off valve unit, a force greater than the reaction force of the spring 404 acts on the hydraulic chamber of the check valve 40, or a force relatively smaller than the reaction force of the spring 404 acts. That is, the check valve 40 may be switched to the open or closed position according to the spring 404 reaction force according to the valve switching state of the hydraulic take-off valve unit and the magnitude of the force acting on the hydraulic chamber.

When one of the plurality of hydraulic outlet valves is switched to the actuator operating position, the hydraulic circuit on the hydraulic oil supply side constitutes a closed circuit, so that the hydraulic chamber 401 of the check valve 40 has a relatively greater force than the spring 404 reaction force. This action is performed, and accordingly, the check valve 40 is switched to the open position, thereby allowing the movement of the hydraulic oil discharged from the actuator to the oil tank side.

On the other hand, when all hydraulic outlet valves are in a neutral position, the pilot pressure acting on the hydraulic chamber 401 is spring 404 as the hydraulic circuit is configured to drain to the oil tank through the first drain line. Not large enough to overcome the reaction force, the check valve 40 remains closed, and accordingly the movement of the hydraulic oil in the actuator to the oil tank side is blocked.

The operation of the present invention will be schematically described with reference to FIGS. 4 to 6.

4 to 6 is an operating state diagram showing the flow of hydraulic oil according to the switching state of the hydraulic outlet valve unit, among the three hydraulic outlet valves constituting the hydraulic outlet valve unit, the hydraulic outlet valve (hereinafter referred to as 'second hydraulic outlet valve' Let's take a look at the flow of hydraulic oil, the actuator operation, and the opening and closing state of the check valve when the actuator rises and falls, and all hydraulic outlet valves are switched to the neutral side.

First, looking at the case where the second hydraulic outlet valve is switched to the actuator rising side as shown in FIG. 4, the second hydraulic outlet valve is switched to the actuator rising side, and at the same time, a closed circuit is constructed, and accordingly, it is checked through the operating pressure supply line. The pilot valve acting on the valve opens the check valve and allows the flow of hydraulic fluid through the second drain line.

With the opening of the check valve, the flow of hydraulic oil through the second oil drain line is allowed, and the hydraulic oil supplied to the second hydraulic outlet valve through the oil supply line is moved to the hydraulic chamber on the rising side of the actuator via P port and A port, The hydraulic oil filled in the opposite hydraulic chamber is drained into the oil tank 50 by sequentially passing through the B port and the R port, the second drain line and the first drain line.

Conversely, when the second hydraulic outlet valve is switched to the actuator lower side as shown in FIG. 5, the closed circuit is configured simultaneously with switching of the actuator lower side of the second hydraulic outlet valve, and similarly acts on the check valve through the operating pressure supply line. At the pilot pressure, the check valve is opened and the flow of hydraulic oil through the second drain line is allowed.

In this state, the hydraulic oil supplied to the second hydraulic take-off valve through the lubrication line is moved to the hydraulic chamber on the lower side of the actuator through P ports and B ports, and the hydraulic oil filled in the opposite hydraulic chambers is A port, R port, and second drain The line and the first drain line are sequentially drained to the oil tank 50.

On the other hand, when all hydraulic outlet valves are switched to the neutral position, as shown in Fig. 6, the neutral ports of all valves are connected to each other, so that the operating oil supplied through the oil supply line is drained into the oil tank through the first oil drain line as it is. Therefore, the check valve is kept closed so that the flow of hydraulic oil through the second drain line is blocked and oil leakage is prevented.

According to the hydraulic oil extraction hydraulic circuit according to an embodiment of the present invention as described above, a simple change to change the position of a part of the hydraulic line and the position of the check valve causes the oil leakage (LEAK) of the hydraulic circuit in the neutral state of the valve even with only one check valve. It is possible to construct a hydraulic circuit that can effectively prevent the sagging or lifting of the cylinder.

That is, a single check valve is applied to the discharge side of the second drain line that returns the oil to the oil tank by joining the hydraulic oil that drives each actuator, and the hydraulic line is operated so that the check valve can be operated according to the pressure acting on the oil supply line. It is possible to effectively prevent oil leakage in the circuit by simple configuration, and it is a conventional problem with low cost and simple hydraulic circuit configuration (increased cost and complicated hydraulic circuit by using multiple check valves to solve oil leakage) Can solve it.

In the above detailed description of the present invention, only specific embodiments thereof have been described. However, it should be understood that the present invention is not limited to the specific forms mentioned in the detailed description, but rather includes all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. Should be.

10: hydraulic pump
15: Directional control valve
20: floating changeover valve
30: hydraulic cylinder
40: check valve
50: oil tank
60: relief valve
P: Oil supply line
S: Operating pressure supply line
T: Exhaust line
T1: Return line

Claims (5)

Oil supply line to which hydraulic oil is supplied;
A first drain line through which hydraulic oil flows when the valve is neutral;
A second exhaust line through which the operating oil supplied through the oil supply line and driving the actuator is discharged;
A hydraulic outlet valve unit composed of two or more hydraulic outlet valves connected to the oil supply line and the second exhaust line and interconnected through the first exhaust line;
Two or more actuators connected in a cylinder line to allow hydraulic fluid to flow to a port on the outlet side of each hydraulic outlet valve constituting the hydraulic outlet valve unit; And
And a check valve installed on the discharge side of the second oil drain line and connected to an operating pressure supply line on the input side of the oil supply line.
According to claim 1,
The check valve,
When one of the two or more hydraulic outlet valves is switched to the actuator operating side, it is operated at the pilot pressure of the oil supply line transmitted through the operating pressure supply line to open the outlet side flow path of the second exhaust line,
When all of the hydraulic outlet valves are switched to the neutral side, the hydraulic oil extraction hydraulic circuit for driving an external working machine is characterized in that it is configured to be restored in a direction to close the discharge side flow path of the second exhaust line by the restoring force of the inner spring.
According to claim 2,
The check valve is a hydraulic pressure extraction circuit for driving an external working machine, characterized in that the pressure check valve formed inside the pressure chamber communicating with the operating pressure supply line.
The method of claim 3,
In the check valve, when a pilot pressure greater than the reaction force of the inner spring is applied to the pressure chamber, the spool is moved in the axial direction so that the input side and output side flow paths of the valve body can be movably connected by the inner flow path of the spool. Hydraulic oil extraction circuit for driving external work, characterized in that configured to be.
According to claim 1,
The two or more hydraulic outlet valves are connected to the oil supply line and the second exhaust line in parallel, the hydraulic oil extraction hydraulic circuit for driving an external working machine, characterized in that arranged in series on the first exhaust line.

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