KR100998611B1 - Holding Valve for Heavy Construction Equipment - Google Patents

Abstract

The present invention relates to a holding valve for construction equipment, comprising a pilot signal pressure port and a plurality of drain passages, and a holding valve block disposed between a work device actuator and a directional valve; A holding poppet for forming a back chamber holding a high-pressure hydraulic oil provided from a tank side return flow path of the directional valve and temporarily limiting the high load of the work device actuator; A piston for forming a pilot pressure chamber therein and sliding the inside of the pilot pressure chamber when an external pilot pressure signal is applied to release the load; A spool having a spool seat on one side and holding the load in the valve block; A sleeve having a bore for slidingly supporting the spool and a bore seat portion formed at one side of the bore, the sleeve being installed inside the valve block; A plug having a flow passage communicating with a back chamber inside the holding poppet, the plug being installed at a lower end of the sleeve adjacent to the load pressure port; According to the present invention, characterized in that it comprises a resilient member between the plug and the spool sheet portion, the elastic member supporting one side of the spool sheet portion to be seated in the bore sheet portion, Since the spool is structurally supported through the elastic member inside the plug coupled to the sleeve without the need for a double nut or a spool guide, it is possible to significantly reduce cost as well as to increase assemblability.

In addition, it is possible to improve the structural stability through the screw fastening of the plug according to the invention.

Construction equipment, holding valve, plug, directional valve,

Description

Holding Valve for Heavy Construction Equipment

The present invention relates to a holding valve for heavy equipment, and more particularly to a holding valve for construction equipment improved to improve the assembly stability of the holding valve as well as to improve the structural stability of the holding valve.

Under construction equipment such as excavators or loaders can easily perform excavation and loading work according to the operation of the working device of the boom, arm, and bucket. In general, the holding valve for heavy construction equipment is to control the hydraulic pressure of the work device actuator to prevent the natural fall phenomenon due to the leakage of hydraulic fluid at the work device neutral position such as the arm and to perform the flow control valve function when the work device is driven. Used in circuits.

As shown in FIG. 1, the conventional holding valve directionally changes the flow rate P1 of the internal back pressure chamber 2a of the poppet 2 while sliding inside the valve block 1, the sleeve 4, and the sleeve 4. A spool 5 for draining to the return flow path C2 of the valve 10, a spring 6 for elastically supporting sliding movement of the spool 5, a spool guide 9, the spool 5, and a spring 6. ) And a piston (8) for receiving the external pilot signal pressure Pi applied to the pilot port (3) and applying a force perpendicular to the spool (5). Reference numeral 8a denotes a piston pressure chamber formed inside the piston 8, 14 denotes a drain flow path for preventing back pressure of the piston 8, and 15 denotes a poppet spring that elastically supports the poppet 2. .

Typically, the holding valve is connected between the actuator (not shown) and the direction control valve (C) for a work device including a boom or an arm cylinder, and the spool 5 is seated on the sleeve 4 when the holding function is performed. Therefore, leakage of oil from the flow path C1 side applied to the sheet portion of the poppet 2 due to the internal pressure P1 of the poppet 21 is suppressed to C2. This prevents free fall of the boom and the cylinder. On the other hand, when the holding function is released, the piston 8 pushes the spool 5 downward in the drawing by the external pilot signal pressure inputted to the pilot port Pi, so that the back pressure chamber 2a inside the poppet 2 is released. Flow rate P1 is drained through the check valve 12 and the flow path 13.

Ultimately, as the flow rate inside the poppet 2 is drained, the pressure of P1 is lowered so that the acting force of P1 is smaller than the acting force of C1 on the contrary. At this time, the opening of the poppet is made so that the flow rate of C1 flows to C2 so that the held boom or arm cylinder is extended or contracted.

However, the conventional holding valve for construction equipment has a problem that the spool is fixed to the outside of the sleeve by the fixed double nut, the assembly and structural stability is poor.

In order to solve the above problems, an object of the present invention is to provide a holding valve for construction equipment that can improve the assembly as well as cost reduction by removing the double nut or spool guide element that has been required for the conventional holding function. .

One feature of the present invention for achieving the above object of the present invention,

A holding valve block having a pilot signal pressure port and a plurality of drain flow paths, the holding valve block being disposed between the work device actuator and the directional valve;

A holding poppet for forming a back chamber holding a high-pressure hydraulic oil provided from a tank side return flow path of the directional valve and temporarily limiting the high load of the work device actuator;

A piston for forming a pilot pressure chamber therein and sliding the inside of the pilot pressure chamber when an external pilot pressure signal is applied to release the load;

A spool having a spool seat on one side and holding the load in the valve block;

A sleeve having a bore for slidingly supporting the spool and a bore seat portion formed at one side of the bore, the sleeve being installed inside the valve block;

A plug having a flow passage communicating with a back chamber inside the holding poppet, the plug being installed at a lower end of the sleeve adjacent to the load pressure port; And

It is provided between the inside of the plug and the spool seat portion, the elastic member for supporting one side of the spool seat portion so that the spool seat portion is seated in the bore seat portion; to provide a holding valve for construction equipment comprising a.

Another characteristic of the present invention is that the drain flow passage includes a first drain flow passage for releasing the high load pressure formed in the holding poppet inside the opening of the bore seat portion in the sleeve, the check valve on one side of the first drain flow passage To provide a holding valve for construction equipment is installed.

Another feature of the present invention is that the drain passage is formed on one side of the pilot pressure chamber to provide a holding valve for construction equipment for preventing back pressure of the piston.

Another feature of the present invention is to provide a holding valve for construction equipment, the elastic member is composed of a spring.

The holding valve for construction equipment according to the present invention is constructed through a plug inner elastic member structurally coupled to a sleeve without the need for a double nut or a spool guide, thereby greatly reducing cost as well as assembling and stability. .

Hereinafter, with reference to the accompanying drawings in detail the holding valve for construction equipment according to an embodiment of the present invention.

1 is a cross-sectional view schematically showing a holding valve for construction equipment connected to a conventional direction switching valve, Figure 2 is a cross-sectional view schematically showing a holding valve for construction equipment according to an embodiment of the present invention, Figure 3 3A is a cross-sectional view of the sleeve according to the present invention, FIG. 3B is a side view of the spool, and FIG. 3C is an assembly in which the spool is seated inside the sleeve by a plug. It is sectional drawing which shows the state.

The holding valve for heavy equipment according to the present invention includes a pilot signal pressure port 3 and a plurality of drain flow paths 13 and 14, and an actuator (not shown) for a work device including a boom cylinder and an arm cylinder. In the holding valve block for construction equipment including a holding valve block 20 is installed between the direction switching valve (C), performing a holding function to prevent free fall of the working device,

A holding poppet for forming a back chamber 22a for holding a high-pressure hydraulic oil provided from the tank side return flow path 11 of the directional valve C and temporarily limiting the high load at which the work device actuator descends. (22);

A pilot pressure chamber (28a) formed therein, and a piston (28) for sliding inside the pilot pressure chamber (28a) when an external pilot pressure signal is applied to release the high load;

A spool seat portion 25a on one side, the spool 25 holding the high load in the holding valve block 20;

A bore 29 supporting the spool 25 so as to be able to slide and a bore seat portion 29a formed at one side of the bore 29, and a sleeve 24 installed inside the holding valve block 20; ;

A plug 30 having a flow path 31 in communication with the back chamber 22a in the holding poppet 22 and installed at a lower end of the sleeve 26 so as to be adjacent to the back chamber 22a; And

An elastic member is installed between the inside of the plug 30 and the spool sheet portion 25a and supports one side of the spool sheet portion 25a so that the spool sheet portion 25a is seated on the bore sheet portion 29a. (26); is configured to include.

In the configuration of the present invention, one of the drain flow passage 13 for releasing the high load pressure formed in the holding poppet 22 in the opening of the bore seat portion 29a in the sleeve 24 It comprises a, and the check valve 12 is installed on one side of the first drain (13) flow path.

The other one of the drain flow paths is formed at one side of the pilot pressure chamber 28a to form a flow path that prevents back pressure of the piston 28.

The elastic member 26 is composed of a spring, the external pilot signal pressure is introduced from the pilot port 23 so that the piston 28 is spooled to the back pressure chamber 22a of the holding poppet 22. An elastic force opposite the force for pressing the upper portion is provided under the spool 25. Accordingly, in the spool 25, the spool seat portion 25a and the bore seat portion 29a of the sleeve 24 are closed, and the hydraulic pressure in the holding poppet 22 is held in the back pressure chamber 22a.

In the configuration of the holding poppet 22 according to the embodiment of the present invention, the orifice 22b is formed on the upper portion of the holding poppet 22 to communicate with the hydraulic pressure is the same as in the prior art.

Hereinafter, the operation principle of the holding valve for construction equipment according to an embodiment of the present invention in detail.

When the holding valve according to the present invention performs a holding function to prevent the free fall of the working device, for example, the boom or the arm cylinder, as shown in Figure 2, the back pressure chamber 22a inside the holding poppet 22 ) Although the pressure of the pressure P1 and the actuator side pressure C1 for the work device is the same through the orifice 22b, the holding poppet 22 is closed, that is, the tank returned from the actuator side for the work device because the hydraulic pressure area is relatively large on the P1 side. The side flow passage 11 is closed by the seat portion of the holding poppet 22, whereby a working device such as a boom or an arm can be held in a holding state without free fall.

On the other hand, when the holding function is to be released to drive a work tool such as a boom or an arm, when the preset pilot pressure Pi is applied to the piston 28, the piston 28 descends and the upper portion of the spool 25 is lowered. Pushing force is down.

At this time, when the pilot pressure Pi is increased to overcome the elastic force of the elastic member 26 which elastically supports the spool seat portion 25a by the plug 30 at the lower portion of the sleeve 24, the spool 25 is lower in the drawing. It slides along the bore 29, and the flow path inside the sleeve 24 opens so that it may communicate with the back pressure chamber 22a of the poppet 22. As shown in FIG. At this time, the flow path inside the sleeve 24 is connected to the valve seat formed while the flow path 31 and the spool seat portion 25a and the bore seat portion 29a of the spool 25 penetrated through the plug 30 are separated from each other. do.

That is, when the holding function is released, the hydraulic pressure of the actuator port for the work device, which is formed in the back pressure chamber 22a inside the holding poppet 22, causes the flow path 31 of the plug 30, the check valve 14 and the first drain. It drains to the hydraulic tank side via the flow path 13.

Ultimately, the seating state of the holding poppet 22 is opened by the force acting on the holding poppet outside C1 as the back pressure chamber 22a pressure P1 inside the holding poppet 22 is dropped, so that the high load pressure on the actuator port side of the work device is increased. This will be released.

On the other hand, the plug 30 according to the present invention is screwed to the lower portion of the sleeve 24 without having to configure a double nut or a spool guide element, thereby improving structural stability.

1 is a cross-sectional view schematically showing a holding valve for construction equipment connected to a conventional direction switching valve,

Figure 2 is a cross-sectional view schematically showing a holding valve for construction equipment according to an embodiment of the present invention,

Figure 3 shows the coupling state of the sleeve and the holding valve for the valve according to the invention, Figure 3a is a cross-sectional view of the sleeve according to the invention,

3b is a side view of the spool,

3c is a cross-sectional view showing an assembled state in which a spool is seated inside a sleeve by a plug;

Description of the Related Art

20: holding valve

21: valve block

24: sleeve

25: spool

25a: Spool seat

26: elastic member

29: bore

29a: bore seat

30: plug

Claims (4)

A holding valve block having a pilot signal pressure port and a plurality of drain flow paths, the holding valve block being disposed between the work device actuator and the directional valve; A holding poppet for forming a back chamber holding a high-pressure hydraulic oil provided from a tank side return flow path of the directional valve and temporarily limiting the high load of the work device actuator; A piston for forming a pilot pressure chamber therein and sliding the inside of the pilot pressure chamber when an external pilot pressure signal is applied to release the high load; A spool having a spool seat on one side and holding the high load in the holding valve block; A sleeve having a bore for slidingly supporting the spool and a bore seat portion formed at one side of the bore, the sleeve being installed inside the holding valve block; A plug having a flow passage communicating with a back chamber inside the holding poppet, the plug being installed at a lower end of the sleeve to be adjacent to the back chamber; And And an elastic member installed between the plug and the spool seat, the elastic member supporting one side of the spool seat so that the spool seat is seated in the bore seat. The method according to claim 1, The drain flow passage includes a first drain flow passage for releasing the high load pressure formed in the holding poppet when the bore seat portion inside the sleeve is opened, and a check valve is provided at one side of the first drain flow passage. Holding valve for heavy construction equipment. The method according to claim 1, The drain flow passage is formed on one side of the pilot pressure chamber to prevent the back pressure of the piston holding valve for construction equipment. The method according to claim 1, Holding valve for heavy construction equipment, characterized in that the elastic member is composed of a spring.

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