1. A load-sensitive overflow valve is characterized by comprising a valve body (1), a valve seat (4), a valve core (5), a spring (8), a push rod (9), a piston cylinder (10), a piston rod (11) and an end cover (12);

an inner hole along the axial direction of the valve body (1) is formed in the valve body (1), the valve seat (4), the valve core (5) and the spring (8) are sequentially arranged in the inner hole, the valve seat (4) is in interference connection with the valve body (1), a channel coaxial with the inner hole of the valve body (1) is formed in the center of the valve seat (4), and the valve core (5) is tightly pressed on the valve seat (4) through the spring (8);

one end where the valve seat (4) is located is taken as a first end of the valve body (1), one end far away from the valve seat (4) is taken as a second end of the valve body (1), the piston cylinder (10) is connected to the second end of the valve body (1), two ends of the ejector rod (9) are respectively connected to the spring (8) and the piston rod (11), the axial movement of the piston rod (11) and the ejector rod (9) in the piston cylinder (10) and the valve body (1) changes the pressing force of the spring (8) on the valve core (5), and the end cover (12) is connected with the piston cylinder (10);

the first end of the valve body (1) is connected with a system oil duct, a cavity A is formed between the system oil duct and a channel in the center of the valve seat (4), hydraulic oil flows into the cavity A from the system oil duct, an oil port B is formed in the valve body (1), the cavity A is not communicated with the oil port B when the valve core (5) is tightly attached to the valve seat (4), the cavity A is communicated with the oil port B through a gap when the gap is formed between the valve core (5) and the valve seat (4), and the hydraulic oil flows out from the oil port B;

form the C chamber between the hole of spring (8), ejector pin (9) and valve body (1), form the D chamber between ejector pin (9) and piston cylinder (10), form the E chamber between piston rod (11) and piston cylinder (10), A chamber and C chamber intercommunication, C chamber and E chamber intercommunication, the area of action of C intracavity hydraulic oil to ejector pin (9) equals the area of action of E intracavity hydraulic oil to piston rod (11), be equipped with trompil I on piston cylinder (10), the D chamber is through trompil I intercommunication external, forms the F chamber between piston rod (11) and end cover (12), and pressure medium acts on piston rod (11) in the F intracavity.

2. The load-sensitive overflow valve of claim 1, characterized in that a hole G is arranged in the valve body (1), and the cavity A and the cavity C are communicated through the hole G in the valve body (1).

3. The load-sensitive overflow valve according to claim 1, wherein the valve body (1) is provided with an opening, the piston cylinder (10) is provided with an opening, a pipeline H is connected with the openings of the valve body (1) and the piston cylinder (10), and the cavity C is communicated with the cavity E through the pipeline H.

4. The load-sensitive overflow valve according to claim 1, wherein the end cap (12) is screwed with the piston cylinder (10), the piston rod (11) reciprocates relative to the end cap (12) under the action of a pressure medium, and a first sealing ring and a second sealing ring are sequentially arranged on a connecting section of the end cap (12) and the piston rod (11) along the axial direction of the piston rod (11), the first sealing ring is used for sealing the cavity E, and the second sealing ring is used for sealing the cavity F.

5. The load-sensitive overflow valve according to claim 4, wherein the end cap (12) is provided with a pressure relief groove at a position between the first sealing ring and the second sealing ring, and the end cap (12) is further provided with a leakage port J, and the leakage port J is communicated with the pressure relief groove.

6. The load-sensitive overflow valve of claim 5, wherein a pressure switch alarm is externally connected to the leakage port J.

7. A load-sensitive overflow valve according to claim 1 characterised in that the valve seat (4) is mounted in the bore of the valve body (1) by means of a seat nut (2) and a locknut (3).

8. The load-sensitive overflow valve of claim 1, wherein the shape of the end surface of the valve core (5) contacting the valve seat (4) is a conical surface, and the shape of the end surface of the valve core (5) is matched with the shape of the valve seat (4).

9. The load-sensitive overflow valve according to claim 1, characterized by further comprising a valve core sleeve (6), wherein the outer circle of the valve core sleeve (6) is in interference fit with the inner hole of the valve body (1), the inner hole of the valve core sleeve (6) is in clearance fit with the outer circle of the valve core (5), and the valve core (5) reciprocates along the valve core sleeve (6).

10. A load-sensitive overflow valve according to claim 1, characterised in that the spring (8) presses on the valve element (5) via the spring seat (7) and thereby presses the valve element (5) against the valve seat (4).

Background

In the field of hydraulic control, an overflow valve is an indispensable component in a hydraulic system and has the functions of protecting each element in the hydraulic system, maintaining the working pressure of the hydraulic system and preventing the working pressure from being too high so as to avoid damaging each component.

In a hydraulic system, an application scenario with a large-range change of system load exists, high-pressure overflow is mainly performed through a set overflow valve, and the overflow pressure of the high-pressure overflow valve is higher than the pressure required when the load is maximum. However, when the load is small, the system pressure is small, and as the parameters of the overflow valve are set, the parameters cannot be changed, the actual system pressure still rises to the set high pressure of the overflow valve, so that great energy waste is caused. The wasted energy is converted into heat energy, so that the temperature of the system is rapidly increased, the burden of a cooling system is increased, and the energy is wasted again. And the hydraulic system always works under the working conditions of high temperature and high pressure, and the service life of a sealing element, an element and the like are all affected badly.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a load-sensitive overflow valve, wherein the pretightening force acting on a valve core changes along with the load pressure, so that the opening pressure of the overflow valve is in positive correlation with the change of the load of a hydraulic system, the opening pressure and the load are kept in a smaller pressure difference range, and the overflow valve can automatically adjust the opening pressure of the valve core according to the system load, thereby achieving the purposes of saving energy, protecting a system sealing element and prolonging the service life of system elements and parts.

The purpose of the invention can be realized by the following technical scheme:

a load-sensitive overflow valve comprises a valve body, a valve seat, a valve core, a spring, an ejector rod, a piston cylinder, a piston rod and an end cover;

an inner hole along the axial direction of the valve body is formed in the valve body, the valve seat, the valve core and the spring are sequentially arranged in the inner hole, the valve seat is in interference connection with the valve body, a channel coaxial with the inner hole is formed in the center of the valve seat, and the valve core is tightly pressed on the valve seat through the spring;

the end where the valve seat is located is taken as a first end of the valve body, the end far away from the valve seat is taken as a second end of the valve body, the piston cylinder is connected to the second end of the valve body, two ends of the ejector rod are respectively connected to the spring and the piston rod, the axial movement of the piston rod and the ejector rod in the piston cylinder and the valve body changes the pressing force of the spring on the valve core, and the end cover is connected with the piston cylinder;

the first end of the valve body is connected with a system oil duct, a cavity A is formed between the system oil duct and a channel in the center of the valve seat, hydraulic oil flows into the cavity A from the system oil duct, an oil port B is formed in the valve body, the hydraulic oil exerts pressure on the valve element, when the pressure is small, the valve element is tightly attached to the valve seat, the cavity A is not communicated with the oil port B, when the pressure is large, a gap is formed between the valve element and the valve seat, the cavity A is communicated with the oil port B, and the hydraulic oil flows out from the oil port B;

a C cavity is formed among the spring, the ejector rod and an inner hole of the valve body, a D cavity is formed among the ejector rod and the piston cylinder, an E cavity is formed among the piston rod and the piston cylinder, the A cavity is communicated with the C cavity, the C cavity is communicated with the E cavity, the action area of hydraulic oil in the C cavity on the ejector rod is equal to that of hydraulic oil in the E cavity on the piston rod, an opening I is formed in the piston cylinder, the D cavity is communicated with the outside through the opening I, an F cavity is formed between the piston rod and the end cover, a pressure medium in direct proportion to a load acts on the upper end of the piston rod through the F cavity, when the load is increased, the pressure of the pressure medium acting on the piston rod is increased, and the pressure for opening the overflow valve is increased; when the load becomes smaller, the pressure of the pressure medium acting on the piston rod becomes smaller, and the pressure for opening the overflow valve is reduced.

Preferably, the cavity A, the cavity C and the cavity E are communicated, and the acting area of the hydraulic oil in the cavity C on the ejector rod is equal to the acting area of the hydraulic oil in the cavity E on the piston rod, so that the upward acting force and the downward acting force acting on the ejector rod and piston rod combined body can be mutually offset no matter how the system pressure fluctuates, and the fluctuation of the system pressure can be shielded outside.

Preferably, a pore passage G is arranged in the valve body, and the cavity A and the cavity C are communicated through the pore passage G in the valve body.

Preferably, the valve body is provided with an opening, the piston cylinder is provided with an opening, the pipeline H is connected with the openings on the valve body and the piston cylinder, and the cavity C is communicated with the cavity E through the pipeline H.

Preferably, the cavity D is communicated with a normal-pressure oil tank through an opening I.

Preferably, the end cover is in threaded connection with the piston cylinder, the piston rod reciprocates relative to the end cover under the action of pressure media, a first sealing ring and a second sealing ring are sequentially arranged on a connecting section of the end cover and the piston rod along the axial direction of the piston rod, the first sealing ring is used for sealing the cavity E, and the second sealing ring is used for sealing the cavity F.

Preferably, the end cover is provided with a pressure relief groove at a position between the first sealing ring and the second sealing ring, and the end cover is further provided with a leakage port J which is communicated with the pressure relief groove.

Preferably, a pressure switch alarm device is connected outside the leakage port J.

Preferably, the valve seat is installed in the inner hole of the valve body through a valve seat nut and a locknut, and the valve seat nut and the locknut are used for axially positioning the valve seat.

Preferably, the shape of the end face of the valve core, which is in contact with the valve seat, is a conical surface, and the shape of the end face of the valve core is matched with the shape of the valve seat.

Preferably, the valve core sleeve is arranged in an inner hole of the valve body, the outer circle of the valve core sleeve is in interference fit with the inner hole of the valve body, the inner hole of the valve core sleeve is in clearance fit with the outer circle of the valve core, the valve core reciprocates along the valve core sleeve, and the valve core sleeve plays an axial guide role on the valve core.

Preferably, the spring is pressed against the valve element by a spring seat, thereby pressing the valve element against the valve seat.

Compared with the prior art, the invention has the following beneficial effects:

(1) the pretightening force acting on the valve core changes along with the load, so that the opening pressure of the overflow valve is in positive correlation with the change of the load of a hydraulic system, the opening pressure and the pressure required by the load are kept in a smaller pressure difference range, and the overflow valve can automatically adjust the opening pressure of the valve core according to the change of the load, thereby achieving the purposes of saving energy, protecting a system sealing element and prolonging the service life of system elements and parts.

(2) The design of the mutually communicated cavity A, cavity C and cavity E, the action area of the hydraulic oil in the cavity C on the ejector rod is equal to the action area of the hydraulic oil in the cavity E on the piston rod, and the upward and downward acting forces acting on the ejector rod and piston rod assembly can be mutually offset no matter how the system pressure fluctuates, so that the pressure balance design can shield the influence of the system pressure fluctuation on the overflow valve.

(3) Two sealing rings on the end cover are used for sealing the E cavity and the F cavity, a pressure relief groove is formed between the two sealing rings, the pressure of hydraulic oil in the E cavity or the pressure medium in the F cavity during leakage can be converted into normal pressure, the pressure medium and the hydraulic oil are prevented from being polluted by each other due to the fact that the hydraulic oil flows into the opposite cavity, a leakage opening J on the pressure relief groove is externally connected with a pressure switch alarm device, the alarm can be timely given when leakage occurs, and the purposes of series cavity isolation and leakage detection are achieved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

reference numerals: 1. the valve comprises a valve body, 2, a locknut, 3, a valve seat nut, 4, a valve seat, 5, a valve core, 6, a valve core sleeve, 7, a spring seat, 8, a spring, 9, an ejector rod, 10, a piston cylinder, 11, a piston rod, 12 and an end cover.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. Parts are exaggerated in the drawing where appropriate for clarity of illustration.

In the description of the embodiments of the present application, it is to be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, refer to the orientation or positional relationship as shown in the drawings, or as conventionally placed in use of the product of the application, or as conventionally understood by those skilled in the art, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be considered as limiting the present application.

Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Example 1:

a load-sensitive overflow valve is shown in figure 1 and comprises a valve body 1, a valve seat nut 2, a locknut 3, a valve seat 4, a valve core 5, a valve core sleeve 6, a spring seat 7, a spring 8, an ejector rod 9, a piston cylinder 10, a piston rod 11 and an end cover 12.

An inner hole along the axial direction of the valve body 1 is formed in the valve body 1, the valve seat 4, the valve core 5 and the spring 8 are sequentially arranged in the inner hole, the valve seat 4 is in interference connection with the valve body 1, a channel coaxial with the inner hole of the valve body 1 is formed in the center of the valve seat 4, and the valve seat 4 is axially positioned and prevented from being loosened through the valve seat nut 2 and the locknut 3. The valve core sleeve 6 plays an axial guiding role for the valve core 4, the spring 8 is pressed on the valve core 5 through the spring seat 7, and the opening pressure of the valve core 5 is determined by the pressing force of the spring 8. The shape of the end face of the valve core 5 contacting the valve seat 4 is a conical surface, and the shape of the end face of the valve core 5 is matched with the shape of the inner round orifice of the valve seat 4. The excircle of the valve core sleeve 6 is in interference fit with the inner hole of the valve body 1, the inner hole of the valve core sleeve 6 is in clearance fit with the excircle of the valve core 5, the valve core 5 reciprocates along the valve core sleeve 6, and the valve core sleeve 6 plays an axial guide role on the valve core 5.

The end where the valve seat 4 is located is used as a first end of the valve body 1, the end far away from the valve seat 4 is used as a second end of the valve body 1, the piston cylinder 10 is connected to the second end of the valve body 1, two ends of the ejector rod 9 are respectively connected to the spring 8 and the piston rod 11, the axial movement of the piston rod 11 and the ejector rod 9 in the piston cylinder 10 and the valve body 1 determines the pressing force of the spring 8 on the valve core 5, and the end cover 12 is connected with the piston cylinder 10.

The first end of the valve body 1 is connected with a system oil duct, a cavity A is formed between the system oil duct and a channel in the center of the valve seat 4, hydraulic oil flows into the cavity A from the system oil duct, an oil port B is formed in the valve body 1, when the valve core 5 is tightly attached to the valve seat 4, the cavity A is not communicated with the oil port B, and when a gap is opened between the valve core 5 and the valve seat 4, the hydraulic oil overflows from the cavity A to the oil port B and flows out.

Spring 8, form the C chamber between the hole in ejector pin 9 and the valve body 1, form the D chamber between ejector pin 9 and the piston cylinder 10, form the E chamber between piston rod 11 and the piston cylinder 10, A chamber and C chamber intercommunication, the effective area of C intracavity hydraulic oil to ejector pin 9 equals the effective area of E intracavity hydraulic oil to piston rod 11, be equipped with trompil I on the piston cylinder 10, the D chamber is through trompil I intercommunication external, form the F chamber between piston rod 11 and the end cover 12, pressure medium proportional with the load acts on piston rod 11 top.

In this embodiment, the C chamber is communicated with the E chamber, the annular cross-sectional area of the E chamber is equal to the cross-sectional area of the long rod of the ejector rod 9, the end protruding parts of the ejector rod 9 and the piston rod 11 are not considered, and the cross sections of the ejector rod 9 and the piston rod 11 are the same, so that the acting area of the hydraulic oil in the C chamber on the ejector rod 9 is equal to the acting area of the hydraulic oil in the E chamber on the piston rod 11.

The volume and the processing cost of overflow valve are considered in this application, are equipped with pore G in valve body 1, and A chamber and C chamber communicate through pore G in the valve body 1. The valve body 1 is provided with an opening, the piston cylinder 10 is provided with an opening, the pipeline H is connected with the openings on the valve body 1 and the piston cylinder 10, and the cavity C is communicated with the cavity E through the pipeline H. In other embodiments, the chamber a, the chamber C and the chamber E may be connected in other ways.

The D cavity is arranged between the C cavity and the E cavity, and hydraulic oil in the C cavity and the E cavity can leak from a gap between the piston rod 11 and the piston cylinder 10 in a micro-seepage mode, so that in the embodiment, the D cavity is communicated with a normal-pressure oil tank through the opening I to collect the hydraulic oil, and in other embodiments, the D cavity can be directly communicated with outside air.

As shown in fig. 1, the top rod 9 is matched with the piston rod 11, the piston rod 11 is matched with the piston rod 10 and the end cover 12, the lower end of the piston rod 11 is pressed on the upper end face of the top rod 9, the end cover 12 is matched with an inner hole of the piston cylinder 10, the end cover 12 is in threaded connection with the piston cylinder 10, and the end cover 12 is connected with a flange of the piston cylinder 10 through a bolt.

The valve core 5 is pressed on the valve seat 4 by the spring 8, the pre-tightening force of the spring 8 is derived from the force exerted on the spring 8 by the ejector rod 9 and the piston rod 11, and the force exerted on the spring 8 by the ejector rod 9 and the piston rod 11 is derived from the pressure of hydraulic oil in the cavity E and the cavity F. When hydraulic oil flows into the oil passage of the system, if the acting force of the hydraulic oil on the valve core 5 is smaller than or equal to the pre-tightening force of the spring 8 on the valve core 5, the valve core 5 cannot be jacked open, and if the acting force of the hydraulic oil is larger than the pre-tightening force of the spring 8, the valve core 5 is jacked open and flows into the oil return tank from the oil port B.

In the overflow valve provided by the application, the automatic pressure regulating function of the adaptive variable-load hydraulic system is mainly realized by the cavity C and the parts above. Because the cavity A, the cavity C and the cavity E are communicated, and the annular area of the cavity E is equal to the long rod sectional area of the ejector rod 9 with the cavity C (namely the actual action area of the hydraulic oil in the cavity C on the ejector rod 9), the upward acting force and the downward acting force of the cavity E on the combination body of the ejector rod 9 and the piston rod 11 can be mutually offset no matter how the system pressure fluctuates, so that the fluctuation of the system pressure can be shielded. If the E cavity is not designed to offset the pressure of the C cavity, when the system pressure changes, the upward acting force of the C cavity on the ejector rod 9 changes, the pressing force of the ejector rod 9 on the spring 8 changes, so that the opening pressure of the overflow valve changes, and the direction of the change of the opening pressure is opposite to the actual demand direction of the system, so that the normal operation of the system is influenced. Therefore, the pressure balance design can effectively shield the influence of system pressure fluctuation on the overflow valve.

Through the design of this application, can effectively shield the influence of system's pressure fluctuation to the overflow valve, make ejector pin 9 and the final pressure that receives of piston rod 11 combination only come from the F chamber, the pressure that the spring 8 upper end packing force acted on the top of piston rod 11 for F chamber pressure promptly. The pressure of the pressure medium is in direct proportion to the load, when the load is increased, the pressure of the pressure medium acting on the piston rod 11 is increased, the acting force pressing the top of the spring 8 is also increased, the pretightening force of the spring 8 acting on the valve core 5 through the spring seat 7 is also increased, and the opening pressure (A cavity pressure) required by the valve core 5 is increased immediately. Conversely, when the load becomes smaller, the pressure of the pressure medium acting on the piston rod 11 becomes smaller, and the opening pressure (a chamber pressure) required for the valve element 5 decreases. Therefore, the opening pressure of the overflow valve is positively correlated with the change of the load of the hydraulic system, and the opening pressure and the load are kept in a smaller pressure difference range, thereby achieving the purposes of saving energy, protecting a system sealing element and prolonging the service life of system elements and parts.

The spring 8 is arranged between the spring seat 7 and the ejector rod 9, one function is to transmit the pressing force of the upper ejector rod 9 to the valve core 5, and the other function is to buffer. When the pressure of the system changes rapidly, the valve core 5 has high movement speed and short stroke, and due to the buffer action in the middle of the spring, the speed of the ejector rod 9 and the piston 11 is reduced, the stroke is reduced, the abrasion of the dynamic seal is reduced, the leakage risk is reduced, and the influence of the friction force of the dynamic seal on the pressure control is reduced.

As shown in fig. 1, the piston rod 11 reciprocates relative to the end cap 12, and along the axial direction of the piston rod 11, a first sealing ring and a second sealing ring are sequentially arranged at the connecting section of the end cap 12 and the piston rod 11, the first sealing ring is used for sealing the cavity E, and the second sealing ring is used for sealing the cavity F. The end cover 12 is provided with a pressure relief groove at a position between the first sealing ring and the second sealing ring, and the end cover 12 is further provided with a leakage port J which is communicated with the pressure relief groove. When the hydraulic oil pump works normally, the pressure medium in the cavity F at the upper end and the hydraulic oil in the cavity E at the lower end cannot leak. However, when the first sealing ring or the second sealing ring leaks due to various reasons, the pressure relief groove can convert the pressure of the hydraulic oil in the cavity E or the pressure medium in the cavity F during leakage into normal pressure, and the pressure medium and the hydraulic oil are prevented from being polluted by each other due to the fact that the hydraulic oil flows into the opposite cavity, so that the purity of the upper pressure medium and the purity of the lower hydraulic oil are guaranteed. The leakage opening J is externally connected with a pressure switch alarm device, when leakage occurs, the pressure switch alarm device sends alarm information, and workers can disassemble and inspect to determine reasons and repair in time so as to avoid influencing a hydraulic system.

Traditional overflow valve, in order to guarantee hydraulic system's commonality under the different load circumstances, its cracking pressure can be slightly higher than the highest load usually, no matter the load size, hydraulic system all need maintain fixed high-pressure operation, and unnecessary energy becomes the heat and gets into the system, causes the system temperature to rise rapidly, then just needs to dispose powerful cooling system, and its purchase cost and running cost are all higher. Meanwhile, the hydraulic system always works under the working conditions of high temperature and high pressure, and the service life of a sealing element and an element and the like are all affected badly.

The overflow valve provided by the application can automatically adjust the opening pressure of the valve core 5 according to the load, does not need to maintain fixed high pressure, effectively solves energy waste, reduces the power of a cooling system, and saves energy; meanwhile, the heating value of the oil system can be reduced, unnecessary high pressure in the system is avoided, and the service life of a sealing element and an element is prolonged. Thereby reducing the manufacturing cost and the operation cost of the system on the whole and prolonging the service life of the whole machine.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.