KR20220167134A - Pressure control valve - Google Patents

Abstract

An objective of the present invention is to provide a pressure control valve capable of stably controlling a higher hydraulic pressure by controlling a movable section of an orifice. According to the embodiments of the present invention, a pressure control valve comprises: a main valve coupled to a hydraulic tank and through which a fluid of a hydraulic system can flow into one side; a pilot valve coupled to the main valve and opened only when the hydraulic pressure is greater than the limit pressure; and an orifice poppet in which a passage having a predetermined diameter is formed on a central axis to control the passing flow rate. The main valve may include a cylindrical main valve body with hollow inside, and a main valve poppet provided inside the main valve body. The orifice poppet may include a damping part exposed to the outside of a front side of the main valve poppet.

Description

Pressure control valve {PRESSURE CONTROL VALVE}

The present invention relates to a pressure control valve, and more particularly, to a pressure control valve capable of controlling a higher hydraulic pressure, including an orifice poppet having a damping unit capable of defining a moving interval.

In general, cranes, construction equipment, or industrial equipment use hydraulic circuit systems for driving various work machines mounted on heavy equipment using pressure oil discharged from a hydraulic pump. The hydraulic oil discharged from the hydraulic pump is supplied to the actuators of each work machine. At this time, the relief valve or pressure control valve provided in the hydraulic circuit system regulates the maximum pressure to protect the entire hydraulic circuit system including the driving source from excessive load. perform the function of

The pressure control valve may perform a function of maintaining the pressure in the circuit below the set value by discharging part or all of the fluid when the pressure in the circuit reaches the set pressure of the valve.

Korean Patent Laid-open Publication No. 10-2005-0081056 discloses a pressure control valve having a pilot poppet and having a variable set pressure as one of the pressure control valves.

The prior art discloses a pressure control valve in which a signal passage is installed inside a piston that pressurizes a pilot poppet spring.

However, in the prior art, when a strong hydraulic pressure is applied instantaneously, the inflow flow rate cannot be controlled, so there is a problem in that the maximum controllable pressure is low.

In addition, since the outer diameter of the piston and the inner diameter of the pilot poppet match, there is a problem in that the occurrence rate of defective products is high during the coupling process.

Furthermore, when the strong hydraulic pressure is strong, flow occurs in the pressure control valve, so that the coupling is released from the hydraulic tank or oil leakage occurs.

An object of the present invention is to provide a pressure control valve capable of stably controlling a higher hydraulic pressure by controlling a movable section of an orifice.

In addition, an object of the present invention is to provide a pressure control valve capable of opening and closing a plurality of passages step by step to prevent flow or vortex generation despite high hydraulic pressure.

Furthermore, an object of the present invention is to provide a pressure control valve capable of reducing production time and production man-hours by integrating a plurality of components.

In order to achieve the above object, a pressure control valve according to an embodiment of the present invention is coupled to a hydraulic tank, the main valve into which the fluid of the hydraulic system can be introduced to one side; a pilot valve coupled to the main valve and opened only when the hydraulic pressure exceeds a limit pressure; and an orifice poppet having a flow path having a predetermined diameter formed on the central axis to control a passing flow rate. The main valve includes a cylindrical main valve body having an empty interior; a main valve poppet provided inside the main valve body; and a first elastic body disposed between the main valve poppet and the pilot valve. The orifice poppet includes a hollow inlet through which fluid is guided; a seating portion connected to the rear of the inlet and having a diameter longer than that of the inlet; and a damping unit connected to the front side of the inlet unit and exposed to the outside of the front side of the main valve poppet. can include

Meanwhile, the main valve poppet may further include a plurality of multi-stage passages having different diameters through which fluid is guided, and the damping part may be formed to have a diameter longer than a diameter of a front side passage of the main valve poppet. there is.

In addition, the orifice poppet may include a seating portion provided to be in contact with an inner circumferential surface of the pilot valve poppet; The main valve poppet may include at least two or more inflow passages having different diameters, and the seat portion may be formed longer than an outer diameter of at least one of the passages of the main valve poppet.

Meanwhile, the passage of the main valve poppet may be sealed by the seating portion when the pressure applied to the orifice poppet is less than or equal to a limit pressure.

At this time, the main valve body may include a first communication hole opened and closed by the main valve poppet; and a second communication hole opened and closed by the pilot valve. Including, the first communication hole may maintain a closed state while the second communication hole is open.

On the other hand, the orifice poppet, the compensation passage communicating the front and rear of the damping unit; Further, the main valve poppet may be formed such that a point in contact with a virtual extension line of the compensation flow path is inclined toward a central axis.

In this case, a plurality of compensation passages may be provided along the circumference of the passage formed at the center of the damping unit.

Further, the plurality of compensating passages may be equally spaced apart in radial and circumferential directions based on the passage formed at the center of the damping unit.

Meanwhile, the fluid guided to the inside of the main valve poppet can be introduced only through the internal passage of the orifice poppet.

Meanwhile, the main valve may include a sealing part provided between the main valve poppet and the pilot valve; A pressure control valve comprising a.

In addition, the main valve poppet may have an inner circumferential surface stepped at least twice, and may include at least two passages having different diameters.

In this case, the first elastic body may be disposed on a stepped surface of the main valve poppet.

Meanwhile, the damping unit may be detachably coupled to the front side of the inlet unit.

On the other hand, according to the present invention, the pressure control valve that operates when the hydraulic pressure rises above the limit pressure in the hydraulic system is coupled to the hydraulic tank, the main valve into which the fluid of the hydraulic system can flow into one side; and a pilot valve coupled to the main valve and opened only when the hydraulic pressure exceeds a limit pressure. The main valve includes a cylindrical main valve body having an empty interior; a main valve poppet provided inside the main valve body; and a first elastic body disposed between the main valve poppet and the pilot valve. The main valve poppet includes: a plurality of passages having different diameters through which fluid is introduced through communication between front and rear; and a damping unit exposed to the outside of the front side of the main valve body. Including, the damping unit may be formed to have a longer diameter than the diameter of the front side of the main valve body.

At this time, the main valve poppet may include a plurality of compensation passages penetrating the damping unit from front to rear; The main valve body further includes a compensating surface inclined at a point where the fluid discharged through the compensating flow path arrives; may further include.

Meanwhile, the compensating passage may be inclined in a radial direction from the central axis of the damping part from the front to the rear.

In addition, the compensation surface may be inclined to be substantially orthogonal to a virtual extension line of the compensation passage.

According to the present invention, an orifice poppet capable of adjusting the flow rate of the passage is provided, so that flow can be prevented even when the hydraulic pressure rapidly rises.

In addition, according to the present invention, the movement range of the orifice poppet can be physically limited, so that the hydraulic pressure can be normally controlled despite a higher hydraulic pressure.

In addition, according to the present invention, by sequentially discharging the fluid through steps to the outside, it is possible to prevent the occurrence of vortexes.

In addition, according to the present invention, when the orifice poppet is coupled to the main valve poppet, it is possible to minimize the occurrence rate of defective products and reduce production costs.

Furthermore, according to the present invention, it is possible to prevent excessive hydraulic pressure from being applied to the actuator, thereby preventing damage to the actuator and prolonging the life expectancy of the actuator.

1 shows, in particular, a pressure control circuit in a hydraulic circuit according to an embodiment of the present invention.
2 is a perspective view showing a pressure control valve according to an embodiment of the present invention viewed from one side.
3 is a side view showing the pressure control valve according to an embodiment of the present invention viewed from the other side.
4 is a cross-sectional view of a pressure control valve according to an embodiment of the present invention.
5 to 9 are operating state diagrams showing the operation process of the pressure control valve according to an embodiment of the present invention, respectively.
10 is a diagram showing a coupled state in which an orifice poppet is coupled to a main valve poppet according to the first embodiment of the present invention.
11 is a perspective view of an orifice poppet according to a first embodiment of the present invention.
12 is a diagram showing a coupled state in which an orifice poppet is coupled to a main valve poppet according to a second embodiment of the present invention.
13 is a perspective view of an orifice poppet according to a second embodiment of the present invention according to a second embodiment of the present invention.
14 is a diagram and an enlarged view of a coupling state in which an orifice poppet is coupled to a main valve poppet according to a third embodiment of the present invention.
15 is a perspective view of an orifice poppet according to a third embodiment of the present invention.
16 is a schematic cross-sectional view of a main valve in a fourth embodiment of the present invention.
17 is a perspective view of a pilot poppet according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. This is not intended to limit the present invention to specific embodiments, and should be construed as including all changes, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly dictates otherwise.

Unless defined otherwise, all terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries may be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in the present application, interpreted in an ideal or excessively formal meaning. It may not be.

First, with reference to FIG. 1, a hydraulic control system including a pressure control valve according to the present invention will be described.

1 shows, in particular, a pressure control circuit in a hydraulic circuit according to an embodiment of the present invention.

The hydraulic control system 1 according to an embodiment of the present invention includes a power source 100, an actuator 200, a main valve 300, a pilot valve 400, an orifice poppet 500 and a hydraulic tank 600. can include Of course, in addition to the above configuration, configurations for controlling the flow direction of the fluid or controlling the flow rate may be added, but descriptions of the corresponding configurations will be omitted in order to describe the features of the present invention.

First, the power source 100 may include a hydraulic tank 110 and a hydraulic pump 120 .

The hydraulic tank 110 is configured to accommodate the working fluid supplied to the system. In the hydraulic tank 110, the hydraulic tank 110 for supply and the hydraulic tank 600 for recovery may exist as separate configurations or may exist as one configuration.

The hydraulic pump 120 supplies a force for inducing fluid in the hydraulic tank 110 . Various pumps commonly used in the industry can be selected in consideration of the required flow rate, hydraulic pressure, flow rate, and fluid properties.

The actuator 200 refers to a component that converts hydraulic pressure into linear motion.

In general, the actuator 200 may include a cylinder and a piston. A piston is provided inside the cylinder, and when the piston receives pressure from a working fluid, it operates to transform hydraulic pressure into linear motion.

In the present invention, the actuator 200 can transmit a strong pressure by receiving force through a fluid. Therefore, it can be used in heavy construction equipment that requires strong power, such as cranes and excavators.

A hydraulic control system according to an embodiment of the present invention may include a pressure control valve for controlling hydraulic pressure. The pressure control valve may include a main valve 300, a pilot valve 400 and an orifice poppet 500. A detailed description of each configuration will be described later with reference to FIG. 2 or less.

The hydraulic control system according to an embodiment of the present invention may operate the actuator 200 by applying pressure to a working fluid through the hydraulic pump 120 .

When the actuator 200 receives excessive pressure, it may malfunction or be damaged, and its life may be shortened. Therefore, for the stable operation of the actuator 200, the pressure inside the hydraulic control system needs to be maintained below the limit pressure (P _s ).

The pressure control valve may operate when the pressure of the fluid inside the system is higher than the limit pressure (Ps), thereby reducing the pressure.

Specifically, the pressure control valve may maintain a closed state when the pressure of the fluid is less than the limit pressure (Ps). However, when the pressure of the fluid is equal to or greater than the limit pressure (Ps), it operates and can guide a certain amount of fluid to the hydraulic tank 600. Accordingly, the pressure of the working fluid inside the hydraulic system 1 can be reduced.

More specifically, when the hydraulic pressure in the hydraulic system 1 is equal to or greater than the limit pressure Ps, the pilot valve 400 is first opened, and then the main valve 300 is opened to supply the working fluid to the hydraulic tank (in two steps). 600) can be guided. A specific operation process of the pressure control valve will be described later in more detail with reference to FIGS. 5 to 9 .

As described above, the hydraulic control system according to the embodiment of the present invention includes a pressure control valve, and can maintain the hydraulic pressure inside the system below the limit pressure (Ps). Thus, the life expectancy of the actuator 200 can be improved, and malfunction of the actuator 200 can be prevented.

Hereinafter, a detailed configuration of a pressure control valve according to an embodiment of the present invention will be described with reference to FIGS. 2 to 4 .

2 shows a view of the pressure control valve according to an embodiment of the present invention viewed from one side, and FIG. 3 shows a view of the pressure control valve according to an embodiment of the present invention viewed from the other side, and FIG. A cross section of a pressure control valve according to an embodiment of the invention is shown.

2 to 4 , the pressure control valve according to the embodiment of the present invention may include a main valve 300, a pilot valve 400, an orifice poppet 500, and a cover part 700.

The main valve 300 may include a main valve body 310 , a main valve poppet 320 , a first elastic body 330 and a sealing part 340 .

The main valve body 310 may constitute at least a part of the outer shape of the pressure control valve. The main valve body 310 may have a substantially cylindrical shape extending in one direction.

The main valve body 310 may include a front end 311 , a front communication hole 312 , a screw thread 313 , and a rear communication hole 314 .

On the other hand, in the description of the embodiment of the present invention, forward may mean a direction looking at a point where fluid is first introduced into the main valve body 310 based on the pilot valve 400 . Also, it may refer to a direction in which the front end 311 of the main valve body 310 is disposed based on the pilot valve 400 .

Conversely, in the description of the embodiment of the present invention, rear may mean a direction in which the pilot valve 400 is positioned based on the front end 311 of the main valve body 310 .

Therefore, at the front end 311 of the main valve body 310, the flow path may be formed from the front to the rear.

The front end 311 may function as an inlet through which the working fluid initially arrives from the hydraulic circuit to the pressure control valve. The front end 311 may be provided at the front of the pressure control valve. The front end 311 may have a cylindrical configuration with an empty inside.

In an embodiment of the present invention, the inlet portion 510 of the orifice poppet 500 may be formed to protrude more forward than the front end portion 311 . In this case, the fluid inside the hydraulic system 1 may reach the inlet 510 earlier than the front end 311 .

The front communication hole 312 may be formed in a substantially circular shape on an outer circumferential surface of the main valve body 310 . Fluid may be discharged from the inside of the main valve body 310 to the outside through the front communication hole 312 . An operation process of opening/closing the front communication hole 312 will be described later with reference to FIG. 8 .

Referring to FIG. 2 , a plurality of front communication holes 312 may be provided along the outer circumference of the main valve body 310 . The number of front communication holes 312 is selectively variable in consideration of the physical properties of the working fluid in the hydraulic system 1, the set oil pressure, and the flow rate.

A plurality of front communication holes 312 are formed along the outer circumference of the main valve body 310, so that when the front communication holes 312 are opened and the fluid is discharged, directions of flow paths can be maintained in balance. Accordingly, when the front communication hole 312 is opened and the fluid is discharged, it is possible to prevent the flow from occurring or the balance being broken in the pressure control valve due to the repulsive force of the fluid.

The thread 313 is formed on the outer circumferential surface of the main valve body 310, and the pressure control valve may be coupled to the hydraulic tank 600 through the thread 313.

The sealing part 340 may be provided on the rear side of the main valve body 310 .

The sealing unit 340 is provided between the main valve body 310 and the pilot valve 400 to prevent fluid from leaking out of the inner space of the main valve body 310 .

The sealing unit 340 may be a commonly used member for sealing, such as a rubber O-ring or a plastic ring.

The rear communication hole 314 may be connected to the communication hole of the pilot valve 400 . Accordingly, a passage through which the fluid inside the pilot valve 400 is guided to an external space of the pressure control valve may be formed together with the communication hole 440 of the pilot valve 400 .

The main valve poppet 320 is configured to be coupled to the inner circumferential surface of the main valve 300 and may be disposed on the front side of the main valve 300 . The main valve poppet 320 may be formed in an approximate cup shape with a shorter diameter at the front side and a longer diameter toward the rear side.

The main valve poppet 320 may be disposed in an inner space of the main valve body 310 . The main valve poppet 320 is movable forward and backward to open and close the front communication hole 312 .

Specifically, the main valve poppet 320 may have a diameter longer than the diameter of the inlet side of the main valve body 310 and a diameter shorter than the diameter of the rear side of the main valve body 310 . Accordingly, it may be introduced from the rear side of the main valve body 310, and may be engaged by being caught on the front side of the main valve body 310.

A specific shape of the main valve poppet 320 will be described later in detail with reference to FIGS. 10 and 11 .

The first elastic body 330 may be disposed inside the main valve poppet 320 . One side of the first elastic body 330 may contact the inner circumferential surface of the main valve poppet 320 and the other side may be coupled to the pilot valve body 410 . That is, the first elastic body 330 may be provided between the main valve poppet 320 and the pilot valve body 410 .

The first elastic body 330 may prevent the main valve poppet 320 from being moved backward by hydraulic pressure. That is, the main valve poppet 320 may maintain a balanced arrangement in a state in which the hydraulic pressure applied backward is smaller than the elastic force applied forward by the first elastic body 330 .

The pilot valve 400 is coupled to the main valve 300 and can be opened when the hydraulic pressure applied to the front side is greater than or equal to the limit hydraulic pressure Ps.

The pilot valve 400 may include a pilot valve body 410 , a pilot poppet 420 and a second elastic body 430 .

The pilot valve body 410 may form the outer shape of the pilot valve 400 .

The pilot valve body 410 may be formed in an approximate cylindrical shape. Components of the pilot valve 400 may be provided in the inner space of the pilot valve body 410 .

The pilot valve body 410 may be inserted and coupled to the inner circumferential surface of the main valve body 310 . In one embodiment of the present invention, threads may be formed on both sides 315 where the main valve body 310 and the pilot valve body 410 are coupled. In an embodiment in which a screw thread is formed, the main valve body 310 and the pilot valve body 410 may be coupled by being screwed into each other. In this case, the pilot valve body 410 may be integrally coupled to the main valve body 310 in a non-movable manner.

An outer diameter of the pilot valve body 410 may correspond to an inner diameter of the main valve body 310 . Accordingly, leakage of fluid between the main valve body 310 and the pilot valve body 410 can be prevented.

The pilot poppet 420 may be coupled to the front entrance of the pilot valve body 410 . The pilot poppet 420 may be pushed forward by the second elastic body 430 .

In addition, at least a portion of the front end 421 of the pilot poppet 420 may be exposed to the outside of the pilot valve body 410 . Therefore, referring to FIG. 5 , the front end 421 of the pilot poppet 420 may be pushed backward by the fluid accommodated in the inner space of the main valve poppet 320 .

Furthermore, the frontmost side of the front end 421 of the pilot poppet 42 may be formed in a hemispherical shape.

The front end 421 of the pilot poppet 420 may be pushed backward by a fluid while being exposed to the outside. Therefore, the frontmost side 421a of the front end 421 is formed in a hemispherical shape, and the pressure transmitted from all directions can be dispersed to prevent the flow.

The second elastic body 430 is disposed behind the pilot poppet 420. In addition, the second elastic body 430 may be combined with the first cover 710 that is drawn into and coupled to the rear side of the pilot valve 400 . That is, the second elastic body 430 is disposed between the pilot poppet 420 and the first cover 710 to press the pilot poppet 420 forward.

The elastic force of the second elastic body 430 may set the operating standard pressure of the pressure control valve. That is, the start of operation of the pressure control valve is determined by the elastic force of the second elastic body 430 . In the present invention, the second elastic body 430 may be compressed when the hydraulic pressure is equal to or greater than the limit pressure (Ps).

The orifice poppet 500 is disposed on the flow path to set the maximum flow rate flowing into the inner space of the main valve poppet 320 .

The orifice poppet 500 may have a flow path penetrating the front and rear sides. Depending on the cross-sectional area of the passage formed in the orifice poppet 500, the maximum flow rate that can pass can be set. The working fluid may flow into the inner space of the main valve poppet 320 through the passage of the orifice poppet 500 .

In the embodiment of the present invention, the front side of the orifice poppet 500 is disposed on the flow side of the hydraulic system, and a part of the rear side may be provided in the inner space of the main valve poppet 320. The hydraulic pressure formed at the front side of the orifice poppet 500 may be the same as the hydraulic pressure measured between the main valve body 510 and the main valve poppet 520 .

The specific shape of the orifice poppet 500 will be described in detail with reference to FIG. 10 and below.

The cover part 700 is provided at the rear of the pressure control valve and can prevent the working fluid from leaking to the rear of the pressure control valve.

The cover unit 700 may include a first cover 710 and a second cover 720 .

At least a portion of the first cover 710 may be inserted into and coupled to the inner circumferential surface of the pilot valve 400 .

An empty cylindrical hole into which the second elastic body 430 can be inserted may be formed on the front side of the first cover 710 . In order to prevent the second elastic body 430 from falling off, the diameter of the hole may be formed to correspond to the diameter of the second elastic body 430 .

The second cover 720 may be provided at the rear of the pressure control valve. The second cover 720 may prevent the fluid flowing in the inner space of the pressure control valve from leaking to the outside.

Meanwhile, referring to FIG. 4 , the hydraulic pressure measured at the inlet of the main valve body 310 is P1, the hydraulic pressure measured in the inner space between the main valve poppet 320 and the pilot poppet 420 is P2, and the pilot valve Hydraulic pressure measured in the inner space of the body 410 may be defined as P3. Hereinafter, in FIGS. 5 to 9 , P1 , P2 , and P3 denote hydraulic pressures of the aforementioned spaces, respectively.

Referring to FIGS. 5 to 9 , the operation process of the pressure control valve according to an embodiment of the present invention will be described in detail.

5 to 9 each show the operation process of the pressure control valve according to an embodiment of the present invention. For convenience of description, the disposition states of the pressure control valves shown in FIGS. 5 to 9 will be defined as first to fifth states, respectively.

5 shows a first state, which is a state before the pressure control valve operates.

Referring to FIG. 5 , the working fluid guided toward the pressure control valve through the power source 100 flows into the inner space of the main valve body 310 through the front end of the main valve 300 and the orifice poppet 500. .

In the first state, the inlet hydraulic pressure P1 of the main valve body 310 is maintained equal to the internal hydraulic pressure P2 of the main valve poppet 320 . (P1 = P2) Also, the internal oil pressure P2 of the main valve poppet 320 is maintained at a state smaller than the limit pressure Ps. (P1 = P2 < Ps) Therefore, the pilot poppet 420 is pressed forward and fixed.

In the first state, all communication holes of the pressure control valve may remain closed. That is, the front communication hole 312 and the rear communication hole 314 of the main valve 300 and the communication hole 440 of the pilot valve 400 may all remain closed.

6 shows a second state in which the pressure control valve is started to operate.

Referring to FIG. 6 , in the pressure control valve according to an embodiment of the present invention, when the second state starts, the pilot poppet 420 may move backward by a predetermined interval.

Specifically, the hydraulic pressure P2 in the inner space of the main valve poppet 320 presses the front end 421 of the pilot poppet 420 backward. When the hydraulic pressure P2 is greater than the limit pressure Ps, the front end 421 of the pilot poppet 420 may be spaced backward. That is, when the hydraulic pressure P2 received by the front end 421 of the pilot poppet 420 is greater than the elastic force of the second elastic body 430 pressing the rear end of the pilot poppet 420, the pilot poppet 420 ) can move backwards.

The pilot poppet 420 may include a main plate portion 424 formed in an approximate disk shape, and a plurality of bent surfaces 425 formed along an outer circumference of the main plate portion 424 . (See Fig. 15)

The diameter of the main plate part 424 may correspond to the diameter of the inner circumferential surface of the pilot valve body 410 . Thus, the pilot poppet 420 can be coupled to the inner circumferential surface of the pilot valve body 410 without any play.

The bent surface 425 may be recessed by a predetermined width toward the central axis of the pilot poppet 420 .

Therefore, in a state where the pilot poppet 420 is coupled to the inner circumferential surface of the pilot valve body 410, a flow path through which fluid can be guided can be formed between the bent surface 425 and the pilot valve body 410. there is.

The passage is closed when the pilot poppet 420 is pushed forward by the second elastic body 430 . Specifically, when the pilot poppet 420 is pressed forward by the second elastic body 430, the inclined portion 422 and the front entrance of the pilot valve body 410 are hermetically coupled.

At this time, when the hydraulic pressure P2 for pressing the pilot poppet 420 backward is stronger than the forward elastic force of the second elastic body 430, the pilot poppet 420 moves backward by a predetermined distance, Accordingly, the front side inlet of the pilot valve body 410 may be opened.

The fluid accommodated in the inner space of the main valve poppet 320 may be guided rearward when the front inlet of the pilot valve body 410 is opened. The fluid passing through the front side inlet is guided to the passage between the aforementioned pilot poppet 420 and the inner circumferential surface of the pilot valve body 410 and flows out of the pressure control valve. In this way, a state in which the flow path through which fluid passes through the pilot poppet 420 and is guided to the outside of the pressure control valve is opened may be defined as a state in which the pilot valve 400 is opened.

FIG. 7 shows a third state in which fluid discharge through the pilot valve 400 is finished.

In the second state, when fluid flows from the inside of the pilot valve 400 to the outside through the communication hole 440, a large amount of fluid flows from the inside of the main valve poppet 320 to the pilot valve 400 momentarily. do. At this time, since the amount of fluid flowing into the main valve poppet 320 is controlled to a certain amount or less that can pass through the flow path of the orifice poppet 500, the inner space of the main valve poppet 320 is the fluid flowing out of the poppet 320. Since the speed is higher than that of , the amount of fluid accommodated in the inner space is reduced. Accordingly, the hydraulic pressure P2 in the inner space of the main valve poppet 320 rapidly decreases.

When the hydraulic pressure P2 in the inner space of the main valve poppet 320 drops below the limit pressure Ps, the pressure applied to the rear of the pilot poppet 420 becomes stronger than the pressure applied to the front. That is, the elastic force of the second elastic body 430 that presses the pilot poppet 420 from the rear becomes stronger than the hydraulic pressure P2. Accordingly, the net force applied to the pilot poppet 420 is directed forward, and accordingly, the pilot poppet 420 moves forward. When the pilot poppet 420 moves forward, the inlet of the pilot valve 400 is closed.

8 illustrates a fourth state in which the main valve poppet 320 moves backward and the main valve 300 is opened. When the internal hydraulic pressure P2 of the main valve poppet 320 drops in the third state, the inlet hydraulic pressure P1 of the main valve body 310 becomes higher than the internal hydraulic pressure P2 of the main valve poppet.

In an embodiment of the present invention, the pilot valve body 410 may be unmovably and integrally coupled to the main valve body 310 . Therefore, even if the internal hydraulic pressure P2 of the main valve poppet 320 is lower than the internal hydraulic pressure P3 of the pilot valve 400, the pilot valve body 410 does not move.

On the other hand, the main valve poppet 320 is movably provided inside the main valve body 310, so that when the inlet hydraulic pressure P1 of the main valve body 310 is higher than the internal hydraulic pressure P2 of the main valve poppet, The main valve poppet 320 may move rearward.

The main valve poppet 320 may be pushed forward by the first elastic body 330 supported by the pilot valve 400 .

Therefore, when the pressure difference between the inlet hydraulic pressure P1 of the main valve body 310 and the internal hydraulic pressure P2 of the main valve poppet 320 is greater than the elastic force of the first elastic body 330, the main valve body 310 A net force toward the rear may occur.

When the main valve poppet 320 moves backward, the front communication hole 312 of the main valve body 310 may be opened.

Specifically, in a state where the main valve poppet 320 is disposed in the front, the front communication hole 312 of the main valve body 310 is closed by the outer circumferential surface of the main valve poppet 320 . When the main valve poppet 320 moves backward, the front communication hole 312 of the main valve body 310 is opened. Accordingly, a flow path through which the fluid introduced into the inlet of the main valve 300 is directly discharged to the external space through the front communication hole 312 may be formed. For example, the external space may be an internal space of the hydraulic tank 600. A state in which the front communication hole 312 is opened and a flow path through which fluid is guided to the outside is formed may be defined as an open state of the main valve 300 .

9 shows a fifth state in which the main valve body 310 moves forward again.

In the fourth state, when fluid is discharged from the inlet of the main valve 300 through the communication hole, the hydraulic pressure P1 at the front of the main valve drops. When the hydraulic pressure P1 at the front end of the main valve 300 drops and becomes lower than the internal hydraulic pressure P2 of the main valve poppet 320 and the elastic force of the first elastic body 330, the main valve poppet 320 is forced forward. this works

The main valve poppet 320 disposed to be movable forward and backward moves forward by a net force. Accordingly, the front communication hole 312 of the main valve body 310 opened in the fourth state may be closed again.

When the main valve 300 is closed, the hydraulic pressure P1 at the front end of the main valve 300 drops to a state lower than the limit hydraulic pressure Ps. Therefore, the hydraulic pressure of the hydraulic system 1 can be maintained below the limit hydraulic pressure.

In addition, since the hydraulic pressure is gradually lowered through several steps, it is possible to prevent flow or vortex of the fluid from occurring in the pressure control valve.

Hereinafter, a specific shape of the orifice poppet 500 and a coupling structure with the main valve poppet 320 according to embodiments of the present invention will be described with reference to FIGS. 10 to 15 .

10 shows a state in which the orifice poppet 500 is coupled to the main valve poppet 320 according to the first embodiment of the present invention, and FIG. 11 shows the orifice poppet 500 according to the first embodiment of the present invention 12 shows a state in which the orifice poppet 500 is coupled to the main valve poppet 320 according to the second embodiment of the present invention, and FIG. 13 shows a state in which the orifice poppet 500 according to the second embodiment of the present invention An orifice poppet 500 according to the second embodiment of the present invention is shown, and FIG. 14 shows a state in which the orifice poppet 500 is coupled to the main valve poppet 320 according to the third embodiment of the present invention. 15 shows an orifice poppet 500 according to a third embodiment of the present invention.

First, referring to FIGS. 10 and 11 , the main valve poppet 320 according to the first embodiment of the present invention may have multi-stage passages having different diameters on an inner circumferential surface.

Specifically, the main valve poppet 320 may have a first flow path 321 to a fifth flow path 325 having different diameters from the front side to the rear side.

First, the first flow path 321 is provided at the foremost side of the main valve poppet 320 and can function as an inlet through which fluid flows into the main valve poppet 320 .

In the first embodiment, the second flow path 322 may be formed with a smaller diameter than the diameter of the first flow path 321 . Therefore, on the flow path leading from the first flow path 321 to the second flow path 322, the flow path may be substantially narrower. Accordingly, the hydraulic pressure applied to the orifice poppet 500 is lowered, so that the orifice poppet 500 can be prevented from being separated or deformed.

The second passage 322 may have a diameter corresponding to the outer diameter of the orifice poppet 500 . Accordingly. It is possible to prevent the working fluid from leaking between the second flow path 322 and the outer circumferential surface of the orifice poppet 500 .

The third flow path 323 and the fourth flow path 324 are formed to be stepped, so that the first spring can be seated on the stepped surface. (See FIG. 4 ) Therefore, it is possible to prevent the first elastic body 330 from being detached from the disposed position.

The fifth flow passage 325 may form an internal space together with the pilot valve 400 drawn therein. (See Fig. 4)

The diameter of the fifth flow path 325 is formed to correspond to the diameter of the pilot valve body 410, so that the pilot valve body 410 can be inserted into and coupled thereto.

Referring to FIG. 11 , an orifice poppet 500 according to an embodiment of the present invention may be formed in a substantially cylindrical shape with a hole formed on a central axis.

First, the front side of the orifice poppet 500 may be provided with a hollow inlet 510 having a communication hole formed on a central axis to allow fluid to flow therein. The inner diameter of the inlet 510 may be selected according to the flow rate and flow rate required by the pressure control valve, and the nature of the working fluid.

An inner diameter of the inlet portion 510 may be shorter than a diameter of the second passage 322 of the main valve poppet 320 . Accordingly, the maximum flow rate of the fluid flowing into the main valve poppet 320 may be adjusted to a predetermined flow rate or less.

The orifice poppet 500 may further include a seating portion 520 extending from the inlet portion 510 to have a longer outer diameter by a predetermined length.

Referring to FIG. 11 , the seating portion 520 may have a rear diameter longer than a front diameter. That is, the outer circumferential surface of the seating portion 520 may be inclined so that the diameter becomes wider from the front to the rear.

The diameter of the seating portion 520 may be longer than that of the second passage 322 . That is, both the front diameter and the rear diameter of the seat portion 520 may be formed to be longer than the diameter of the second passage 322 .

The orifice poppet 500 may be pushed forward by the first elastic body 330 . Accordingly, the seating portion 520 may close the rear side of the second passage 322 . Accordingly, it is possible to prevent the working fluid from flowing into the inner space of the main valve poppet 320 through the second passage 322 .

An outlet 530 through which fluid flows out into an inner space of the main valve poppet 320 may be formed at a rear side of the orifice poppet 500 .

The outflow part 530 may be formed in a substantially cylindrical shape connected to the rear side of the seating part 520 .

The outer diameter of the outlet part 530 may be longer than the outer diameter of the inlet part and shorter than the outer diameter of the seating part. For example, referring to FIG. 10 , the outer diameter of the front side of the outlet 530 may be longer than the outer diameter of the rear side. Accordingly, separation of the first elastic body 330 coupled to surround the outer circumference of the outlet 530 can be prevented.

Referring to FIGS. 10 and 11 , the passage formed inside the outlet 530 may have a larger diameter going from the front to the rear. More specifically, the internal passage of the outlet 530 may be formed in a funnel shape inclined to be wider toward the rear outlet.

Accordingly, it is possible to prevent the flow direction of the fluid flowing out through the orifice poppet 500 from concentrating toward the rear.

Furthermore, despite the change in the amount of fluid flowing out through the orifice poppet 500, the balance of the amount of fluid in the inner space of the main valve poppet 320 can be maintained. In addition, the generation of vortex of fluid in the inner space of the main valve poppet 320 can be suppressed.

12 and 13, in the second embodiment of the present invention, the pilot poppet 500 may further include a damping unit 540. Hereinafter, in the description of the second embodiment, the main valve poppet 320 ) and the omitted description of the pilot poppet 500 will be borrowed from the description described above in the first embodiment.

The damping part 540 may be formed by being connected to the front side of the inlet part 510 . That is, in the second embodiment of the present invention, the damping unit 540 may be disposed at the front of the pressure control valve.

A flow path may be formed at the center of the damping unit 540 . Accordingly, the fluid introduced from the front of the damping unit 540 may be guided to the outlet 530 via the inlet 510 .

The damping part 540 may have a diameter longer than that of the inlet part 510 . The diameter D1 of the damping part 540 may correspond to the diameter D2 of the first passage 321 .

Specifically, the diameter D1 of the damping part 540 may be equal to or longer than the diameter D2 of the first passage 321 .

Accordingly, even when the orifice poppet 500 is pressed from the front side and moves backward, it is possible to prevent the damping unit 540 from moving backward beyond the point where it meets the first flow path 321 .

When the orifice poppet 500 moves backward by a predetermined distance or more, a large amount of fluid may be introduced between the seating portion 520 and the fourth flow path 324 . In this case, the flow rate controlled by the pressure control valve may be exceeded and the function may be lost.

In the second embodiment of the present invention, the limit movement distance of the orifice poppet 500 may be defined by the damping unit 540 . Accordingly, even if the internal hydraulic pressure of the hydraulic system 1 is instantaneously strong, it is possible to prevent the orifice poppet 500 from falling off. That is, the pressure control valve has an effect of increasing the controllable limit pressure (Ps).

The damping part 540 may be detachably coupled to the inlet part 510 . If the damping part 540 is formed in front of the inlet part 510, a problem may occur in coupling between the orifice poppet 500 and the main valve poppet 320. That is, a problem may occur that the orifice poppet 500 cannot be simply inserted and coupled at the rear of the main valve poppet 320 as in the first embodiment.

The damping unit 540 is detachably coupled to the front of the inlet unit 510, and after coupling the orifice poppet 500 excluding the damping unit 540 to the main valve poppet 320 in the production process, the damping unit 540 ) to the inlet 510 to prevent problems in the production process.

Referring to FIGS. 14 and 15 , in the third embodiment of the present invention, a compensation passage 541 may be formed in the damping part 540 of the orifice poppet 500 .

Specifically, a plurality of compensation passages 541 penetrating the rear surface from the front surface of the damping unit 540 may be formed. A plurality of compensation passages 541 may be provided along the outer circumference of the passage formed at the center of the damping unit 540 .

Intervals between the compensation passages 541 may be formed identically to each other. Accordingly, rotational clearance of the orifice poppet 500 due to the inflowing fluid can be prevented.

Referring to FIG. 14 , the compensation passage 541 may be formed away from the central axis in a radial direction from the front to the rear. That is, the compensation passage 541 may be formed inclined from the axis toward the outer circumference. Accordingly, the fluid passing through the compensation passage 541 may flow out in a direction away from the central axis.

In particular, referring to the enlarged view of FIG. 14 , the fluid flowing out through the compensation passage 541 may meet the inclined surface 321a of the first passage 321 . Accordingly, the damping unit 540 may be pushed forward again by the repulsive force generated by the fluid colliding with the inclined surface 321a.

In particular, when the orifice poppet 500 is moved rearward as the hydraulic pressure formed at the front side of the orifice poppet 500 increases, the distance between the outlet of the compensating passage 541 and the inclined surface 321a becomes shorter.

When the distance between the outlet of the compensation passage 541 and the inclined surface 321a becomes shorter, the fluid discharged from the compensation passage 541 collides with the inclined surface 321a and returns to a stronger reaction force. Accordingly, the damping unit 540 is more strongly pressed toward the front. Therefore, the effect of the damping unit 540 to prevent the orifice poppet 500 from being pushed backward despite strong pressurization can be further improved by the compensating passage 541 .

16 shows a schematic cross-sectional view of a main valve 300 in a fourth embodiment of the present invention.

In the fourth embodiment of the present invention, the main valve poppet 320 may further include a damping part 327 and a compensation passage 327 .

That is, in the fourth embodiment of the present invention, the main valve poppet 320 may be integrally formed with the orifice poppet 500 described above in the third embodiment.

The damping unit 327 may be provided in a disk shape having a predetermined thickness and having a diameter longer than the inner diameter of the front end 310 of the main valve body 310 .

The damping unit 327 may contact the front end 310 when the main valve poppet 320 moves backward, thereby limiting the rearward movement distance of the main valve poppet 320 .

The distance between the damping part 327 and the front end part 310 is preferably designed to be moved to a position where the front communication hole 312 is opened in the aforementioned front communication hole opening step (fourth step, see FIG. 8). Do. Accordingly, in a state in which the damping part 327 and the front end part 310 are in physical contact, the main valve poppet 320 moves backward, and the front communication hole 312 can be opened.

The compensation passage 328 may be formed at a predetermined distance from the central axis of the damping part 327 in a radial direction. A plurality of compensation passages 328 penetrating from the front surface to the rear surface of the damping unit 327 may be formed. A plurality of compensation passages 328 may be provided along the outer circumference of the passage formed at the center of the damping part 327 .

Intervals between the compensation passages 328 may be formed to be the same as each other. Accordingly, it is possible to prevent rotational clearance of the main valve poppet 320 due to the fluid flowing into the compensation passage 328 .

The diameter D3 of the passage formed at the center of the damping unit 327 may be selectively formed in consideration of various environments such as the nature of the working fluid of the hydraulic system 1, hydraulic pressure, and design values of pressure control valves.

The diameter D3 of the passage of the damping part 327 may be the same as that of the first passage 321 . Accordingly, it is possible to control the amount of fluid flowing into the inside, and to prevent a bottle-neck phenomenon that may occur when the fluid is guided from the flow path of the damping unit 327 to the first flow path 321. there is.

As described above, in the fourth embodiment of the present invention, since the orifice-integrated main valve body 320 is provided, design can be simplified, operation stability can be improved, and manufacturing time and cost can be reduced.

17 shows a pilot poppet 420 according to an embodiment of the present invention.

Referring to FIG. 17 , a pilot poppet 420 according to embodiments of the present invention may include a front end part 421, an inclined part 422, a main plate part 424, and a rear end part 423.

The front end 421 is formed in a cylindrical shape and may be introduced into the front entrance of the pilot valve body 410 . Accordingly, at least a portion of the front end 421 may be disposed outside the pilot valve body 410 . (See FIG. 4 ) That is, at least a portion of the front end portion 421 may be disposed in the inner space of the main valve poppet 320 .

The front end 421a of the front end 421 may be formed in a hemispherical shape. As described above, the front end of the front end 421 may be disposed in the inner space of the main valve poppet 320 . Therefore, even if a strong hydraulic pressure is instantaneously applied from the inside of the main valve poppet 320, flow can be prevented by canceling it.

The inclined portion 422 is connected to the front end portion 421, and may be inclined to have a wider diameter on the rear side than on the front side.

The inclined portion 422 may be coupled to the inlet of the pilot valve body 410 . The inclined portion 422 may have a wider cross section on the rear side to seal the inlet of the pilot valve body 410 .

The main plate portion 424 is provided in a substantially disc shape and may be coupled to the inner circumferential surface of the pilot valve body 410 .

Referring to FIG. 17 , the main plate portion 424 may have a thickness in an axial direction greater than a thickness in a circumferential direction. That is, the main plate portion 424 may be formed inclined from the axis toward the circumference. Accordingly, the fluid flowing into the center of the main plate portion 424 can naturally flow in the radial direction along the inclination of the main plate portion 424 . Accordingly, according to the shape of the main plate part 424, the pilot poppet 420 distributes the hydraulic pressure in the radial direction, thereby preventing the generation of flow.

The rear end 423 is formed in a cylindrical shape, and the second elastic body 430 may be coupled thereto. The diameter of the rear end 423 may be formed to correspond to the diameter of the second elastic body 430 . Accordingly, the rear end 423 can prevent the second elastic body 430 from being separated from the disposed position.

The pilot poppet 420 according to an embodiment of the present invention may further include a bent surface 425 .

The bent surface 425 may be formed to be curved toward an axis at the outer circumference of the main plate portion 424 .

The bent surface 425 may function as a passage inside the pilot valve 400 . That is, by forming an empty space between the inner circumferential surface of the pilot valve body 410 and the main plate 424, the fluid can be guided into the empty space.

A plurality of bending surfaces 425 may be provided along the circumference of the main plate portion 424 . When a plurality of bending surfaces 425 are provided, fluid passing through the main plate 424 may be divided into a plurality of passages and guided. Therefore, the hydraulic pressure is substantially equally distributed, and the fluid is guided only to one side, so that the arrangement angle of the pilot poppet 420 is prevented from being changed.

Although specific embodiments of the present invention have been described and shown above, the present invention is not limited to the described embodiments, and those skilled in the art may modify variously to other specific embodiments without departing from the spirit and scope of the present invention. And can be modified, it will be understood that such modifications also fall within the scope of the present invention. Therefore, the scope of the present invention will not be determined by the described embodiments, but will be determined by the technical ideas described in the claims.

1: hydraulic system
100: power source 110: hydraulic tank
120: hydraulic pump
200: actuator
300: first valve 310: main valve body
312: front communication hole 314: rear communication hole
320: main valve poppet 330: first elastic body
400: pilot valve 410: pilot valve body
420, 450: pilot valve poppet 421, 451: front end
422, 452: inclined portion 425: bent surface
440: pilot valve communication hole 455: communication hole
500: orifice 600: hydraulic tank
700: cover part

Claims (18)

In the pressure control valve that operates when the hydraulic pressure rises above the limit pressure in the hydraulic system,
A main valve coupled to a hydraulic tank and into which fluid of the hydraulic system is introduced to one side;
a pilot valve coupled to the main valve and opened only when the hydraulic pressure exceeds a limit pressure; and
An orifice poppet having a passage having a predetermined diameter formed on the central axis to control the passing flow rate; and
The main valve,
Cylindrical main valve body with hollow inside;
a main valve poppet 320 provided inside the main valve body; and
A first elastic body 330 disposed between the main valve poppet and the pilot valve;
The orifice poppet,
A hollow inlet 510 through which fluid is guided;
a seating portion 520 connected to the rear of the inlet and having a diameter longer than that of the inlet; and
A pressure control valve comprising: a damping unit 540 connected to the front of the inlet and exposed to the outside of the front side of the main valve poppet. According to claim 1,
The main valve poppet,
Further comprising a plurality of multi-stage flow passages having different diameters through which the fluid is guided,
The damping part,
A pressure control valve formed to have a longer diameter than a diameter of a passage on a front side of the main valve poppet. According to claim 1,
The orifice poppet,
a seating portion provided to be in contact with an inner circumferential surface of the pilot valve poppet;
Including more,
The main valve poppet,
Including at least two or more inflow channels having different diameters,
the attachment part,
The pressure control valve, characterized in that formed longer than the outer diameter of at least one of the flow path of the main valve poppet. According to claim 3,
The passage of the main valve poppet,
The pressure control valve, characterized in that when the pressure applied to the orifice poppet is less than the limit pressure, it is sealed by the seating portion. According to claim 1,
The main valve body,
a first communication hole opened and closed by the main valve poppet; and
A second communication hole opened and closed by the pilot valve;
The first communication hole,
The pressure control valve, characterized in that the second communication hole is closed from the open state. According to claim 2,
The orifice poppet,
It further includes; a compensation passage communicating the front and rear of the damping unit;
The main valve poppet,
The pressure control valve, characterized in that the point in contact with the virtual extension of the compensation passage is formed inclined toward the central axis. According to claim 1,
The pressure control valve, characterized in that the fluid guided to the inside of the main valve poppet necessarily flows only through the inner passage of the orifice poppet. According to claim 1,
The main valve,
a sealing part provided between the main valve poppet and the pilot valve;
A pressure control valve comprising a. According to claim 1,
The main valve poppet,
A pressure control valve, characterized in that the inner circumferential surface is formed stepwise at least twice, and at least two passages having different diameters are provided. According to claim 9,
The first elastic body,
The pressure control valve, characterized in that disposed on the stepped surface of the main valve poppet. According to claim 1,
The damping part,
A pressure control valve, characterized in that detachably coupled to the front side of the inlet. According to claim 1,
The orifice poppet,
An outlet connected to the rear surface of the seating portion and discharging the fluid introduced through the inlet; further comprising:
The outflow part,
A pressure control valve provided in an inner space of the main valve poppet to guide fluid into the main valve poppet. According to claim 11,
The main valve poppet,
A pressure control valve, characterized in that the diameter of the inner passage is longer than the outer diameter of the inlet. According to claim 11,
The pressure control valve, characterized in that the inner flow path of the outlet is formed in a funnel shape having a diameter wider at the rear than at the front. In the pressure control valve that operates when the hydraulic pressure rises above the limit pressure in the hydraulic system,
A main valve coupled to a hydraulic tank and into which fluid of the hydraulic system is introduced to one side; and
A pilot valve coupled to the main valve and opened only when the hydraulic pressure is greater than or equal to a limit pressure;
The main valve,
Cylindrical main valve body with hollow inside;
a main valve poppet provided inside the main valve body; and
A first elastic body disposed between the main valve poppet and the pilot valve;
The main valve poppet,
a plurality of passages having different diameters through which fluid flows through communication between the front and rear; and
Including; damping portion exposed to the outside of the front side of the main valve body,
The damping part,
The pressure control valve, characterized in that formed to have a longer diameter than the front side diameter of the main valve body. According to claim 15,
The main valve poppet,
It further includes; a plurality of compensation passages penetrating the damping unit from the front to the rear;
The main valve body,
The pressure control valve further comprising a compensating surface inclined at a point where the fluid discharged through the compensating passage reaches. According to claim 16,
As for the compensation flow,
The pressure control valve, characterized in that formed inclined in a radial direction from the central axis of the damping part from the front to the rear. According to claim 17,
The compensation surface is
A pressure control valve formed inclined to be substantially orthogonal to a virtual extension of the compensation passage.

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