阅读说明：本技术 液压控制阀及液压控制系统 (Hydraulic control valve and hydraulic control system ) 是由 松本哲 于晓晨 朱彪 郑诗强 杨密密 于 2020-11-27 设计创作，主要内容包括：本发明提供了一种液压控制阀及液压控制系统,其中,液压控制阀包括：阀体,阀体上设置有进油口、排油口、第一工作油口以及第二工作油口；第一阀芯,可移动地设置在阀体内,第一阀芯内设置有容纳腔,第一阀芯的侧壁上设置有与容纳腔连通的第一通孔、第二通孔和第三通孔；第二阀芯,可移动地设置在容纳腔内,第二阀芯具有使第二通孔和第三通孔连通的连通位置以及使第二通孔和第三通孔隔离的隔离位置。本发明的技术方案解决了现有技术中的液压系统结构复杂,安装局限大以及成本高的缺陷。(The invention provides a hydraulic control valve and a hydraulic control system, wherein the hydraulic control valve comprises: the oil inlet, the oil outlet, the first working oil port and the second working oil port are formed in the valve body; the first valve core is movably arranged in the valve body, an accommodating cavity is formed in the first valve core, and a first through hole, a second through hole and a third through hole which are communicated with the accommodating cavity are formed in the side wall of the first valve core; and the second valve core is movably arranged in the accommodating cavity and has a communication position for communicating the second through hole with the third through hole and an isolation position for isolating the second through hole from the third through hole. The technical scheme of the invention overcomes the defects of complex structure, large installation limit and high cost of the hydraulic system in the prior art.)

1. A hydraulic control valve, comprising:

the hydraulic control valve comprises a valve body (10), wherein an oil inlet (11), an oil discharge port (12), a first working oil port (13) and a second working oil port (14) are formed in the valve body (10), the first working oil port (13) is used for being communicated with a rodless cavity of a controlled cylinder body, and the second working oil port (14) is used for being communicated with a rod cavity of the controlled cylinder body;

the first valve core (20) is movably arranged in the valve body (10), the first valve core (20) is provided with a first position enabling the first working oil port (13) to be communicated with the oil discharge port (12) and enabling the second working oil port (14) to be communicated with the oil inlet (11), and a second position enabling the first working oil port (13) to be communicated with the oil inlet (11) and enabling the second working oil port (14) to be communicated with the oil discharge port (12), an accommodating cavity (30) is arranged in the first valve core (20), and a first through hole (21), a second through hole (22) and a third through hole (23) which are communicated with the accommodating cavity (30) are arranged on the side wall of the first valve core (20);

a second valve core (40) movably disposed in the accommodation chamber (30), the second valve core (40) having a communication position in which the second through hole (22) and the third through hole (23) communicate and an isolation position in which the second through hole (22) and the third through hole (23) are isolated,

when the first valve core (20) is located at the second position, the first through hole (21) is communicated with the first working oil port (13), the second through hole (22) is communicated with the second working oil port (14), and the third through hole (23) is communicated with the oil discharge port (12), so that the pressure of the rodless cavity in the controlled cylinder is communicated with the accommodating cavity (30), and the second valve core (40) is driven to move from the isolation position to the communication position.

2. A hydraulic control valve according to claim 1, characterized in that a flow groove (41) is provided in a side wall of the second spool (40), the second through hole (22) and the third through hole (23) both communicate with the flow groove (41) when the second spool (40) is in the communication position, and the second through hole (22) and/or the third through hole (23) are misaligned with the flow groove (41) when the second spool (40) is in the isolation position.

3. The hydraulic control valve according to claim 2, wherein the third through hole (23) is plural, and the plural third through holes (23) are provided at intervals in the axial direction of the first spool (20), wherein at least one third through hole (23) of the plural third through holes (23) communicates with the overflow groove (41) when the second spool (40) is in the communication position.

4. A hydraulic control valve according to claim 3, characterized in that the aperture of the plurality of third through holes (23) is gradually increased in a direction away from the second through holes (22).

5. The hydraulic control valve according to claim 1, wherein the second spool (40) divides the housing chamber (30) into a first section (31) and a second section (32), the first through hole (21) communicates with the first section (31), the second spool (40) includes a first force-receiving surface (42) facing the first section (31) and a second force-receiving surface (43) facing the second section (32), the second spool (40) further includes a communication hole (44), the communication hole (44) communicates the first section (31) and the second section (32), wherein an area of the first force-receiving surface (42) is larger than an area of the second force-receiving surface (43).

6. The hydraulic control valve according to claim 1, characterized in that an elastic member (50) is provided between the second spool (40) and the first spool (20), and the elastic member (50) applies an elastic force to the second spool (40) in a direction toward the first through hole (21).

7. A hydraulic control valve according to claim 6, characterized in that the end of the first spool (20) is provided with a blocking piece (60), the elastic piece (50) is a spring, and both ends of the spring are respectively arranged in abutment with the second spool (40) and the blocking piece (60).

8. A hydraulic control valve according to claim 7, characterized in that a guide arrangement (70) is provided between the second valve spool (40) and the block piece (60).

9. A hydraulic control valve according to claim 1, characterized in that the inner wall of the first spool (20) is provided with a positioning step (24), and the second spool (40) abuts the positioning step (24) when the second spool (40) is in the isolating position.

10. A hydraulic control system, characterized by comprising a hydraulic control valve (100), the hydraulic control valve (100) being the hydraulic control valve of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of hydraulic control, in particular to a hydraulic control valve and a hydraulic control system.

Background

Two directional control valves are arranged in heavy machinery to control one oil cylinder simultaneously, wherein one directional control valve controls oil inlet and oil outlet of a rod cavity and a rodless cavity of the oil cylinder, and the other directional control valve is a flow regeneration valve. The principle of flow regeneration is as follows: when engineering machinery (such as an excavator) works, when a rod cavity in an oil cylinder descends, the oil pressure of the rodless cavity is very high under the action of gravity, and the rodless cavity is communicated with the rod cavity through an external mechanism device or a mechanism device inside a multi-way valve, so that the oil supply of high-pressure oil in the rodless cavity to the rod cavity is realized, namely, the flow regeneration function is realized, the air suction problem of the rod cavity caused by too high speed is prevented, and the flow is saved at the same time.

However, when the oil cylinder is in heavy load operation, the oil hydraulic pressure of the rodless cavity of the oil cylinder is greater than the pressure of the rod cavity of the oil cylinder, so that the flow regeneration valve in the directional control valve does not work. The oil return area of the rod cavity is small, so that the oil return speed of the rod cavity of the oil cylinder is low, and the oil cylinder is weak in action. In order to solve the problem of weak action of the oil cylinder, in some hydraulic control systems in the prior art, an external valve block (or a cartridge valve) is additionally arranged on an oil return path of a rod cavity of the oil cylinder, so that the oil return speed of the rod cavity is increased, and the action force of the oil cylinder is increased.

However, the above technical solutions have the following problems: the external valve block can only control the oil return of the small cavity of the first oil cylinder independently, namely, the oil return control of the small cavity of the oil cylinder is carried out one by one, if the second oil cylinder also needs the function, another external valve block (or cartridge valve) needs to be additionally arranged, and the like, the more the oil cylinders which need the function are, the more the external valve blocks are added. The external valve block has certain limitation on machinery with limited installation space, and the external valve block (or the oil return control valve) needs to be externally connected with a pipeline to carry out signal transmission and oil discharge, so that the piping difficulty is increased. And each external valve block (or oil return control valve) needs to be controlled by an electromagnetic proportional pressure reducing valve, and the electromagnetic proportional pressure reducing valves on the market at present have imperfect performance and high cost, thereby increasing the cost to a certain extent.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to overcome the defects of complicated structure, large installation limitation and high cost of the hydraulic system in the prior art, so as to provide a hydraulic control valve and a hydraulic control system.

In order to solve the above technical problem, the present invention provides a hydraulic control valve including: the valve body is provided with an oil inlet, an oil discharge port, a first working oil port and a second working oil port, the first working oil port is used for being communicated with a rodless cavity of the controlled cylinder body, and the second working oil port is used for being communicated with a rod cavity of the controlled cylinder body; the first valve core is movably arranged in the valve body and provided with a first position enabling the first working oil port to be communicated with the oil discharge port and the second working oil port to be communicated with the oil inlet and a second position enabling the first working oil port to be communicated with the oil inlet and the second working oil port to be communicated with the oil discharge port, an accommodating cavity is formed in the first valve core, and a first through hole, a second through hole and a third through hole which are communicated with the accommodating cavity are formed in the side wall of the first valve core; the second valve core is movably arranged in the containing cavity and provided with a communicating position enabling the second through hole to be communicated with the third through hole and an isolating position enabling the second through hole to be isolated from the third through hole, wherein when the first valve core is located at the second position, the first through hole is communicated with the first working oil port, the second through hole is communicated with the second working oil port, and the third through hole is communicated with the oil discharge port, so that the pressure of the rodless cavity in the controlled cylinder body is communicated with the containing cavity, and the second valve core is driven to move to the communicating position from the isolating position.

Optionally, a flow through groove is formed in the side wall of the second valve core, when the second valve core is located at a communicating position, the second through hole and the third through hole are both communicated with the flow through groove, and when the second valve core is located at an isolating position, the second through hole and/or the third through hole are/is staggered with the flow through groove.

Optionally, the number of the third through holes is multiple, and the multiple third through holes are arranged at intervals along the axial direction of the first valve core, wherein when the second valve core is in the communication position, at least one of the multiple third through holes is communicated with the overflowing groove.

Optionally, the apertures of the plurality of third through holes gradually increase in a direction away from the second through holes.

Optionally, the second valve core divides the accommodating cavity into a first section and a second section, the first through hole is communicated with the first section, the second valve core comprises a first stress surface facing the first section and a second stress surface facing the second section, the second valve core further comprises a communication hole which is communicated with the first section and the second section, and the area of the first stress surface is larger than that of the second stress surface.

Optionally, an elastic member is provided between the second spool and the first spool, and the elastic member applies an elastic force to the second spool in a direction toward the first through hole.

Optionally, a blocking piece is arranged at an end of the first valve core, the elastic piece is a spring, and two ends of the spring are respectively abutted against the second valve core and the blocking piece.

Optionally, a guide structure is arranged between the second valve core and the blocking piece.

Optionally, a positioning step is provided on an inner wall of the first valve element, and when the second valve element is in the isolation position, the second valve element abuts against the positioning step.

The invention also provides a hydraulic control system which comprises the hydraulic control valve.

The technical scheme of the invention has the following advantages:

by utilizing the technical scheme of the invention, when the controlled oil cylinder works under a heavy load, the first valve core is positioned at the second position, at the moment, the first working oil port is communicated with the oil inlet so as to enable the rodless cavity of the controlled oil cylinder to feed oil, and the second working oil port is communicated with the oil outlet so as to enable the rodless cavity of the controlled oil cylinder to discharge oil. Meanwhile, the first through hole is communicated with the first working oil port, so that hydraulic oil in the rodless cavity enters the accommodating cavity, and the second valve core is pushed to move to the communication position. After the second valve core is located at the communication position, the second valve core communicates the second through hole with the third through hole, so that hydraulic oil in the rodless cavity can be discharged from the second working oil port, the second through hole, the third through hole and the oil discharge port, an additional oil discharge channel is also added, the oil return speed is accelerated, and the action force of the oil cylinder is enhanced. The technical effect of increasing the oil discharge channel with the rod cavity is achieved only by improving the control valve of the controlled oil cylinder, and then an external valve block or a cartridge valve does not need to be additionally added in the hydraulic control system, so that the structure of the hydraulic control system is simplified, the cost is reduced, and the limitation caused by the installation space of equipment is reduced. Therefore, the technical scheme of the invention overcomes the defects of complex structure, large installation limit and high cost of the hydraulic system in the prior art.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 shows a schematic of the construction of a hydraulic control valve of the present invention;

FIG. 2 shows a schematic structural view of the left side of the hydraulic control valve of FIG. 1;

FIG. 3 shows a schematic diagram of the construction of the right side of the hydraulic control valve of FIG. 1;

FIG. 4 is a schematic view showing the structure of a third through hole of the hydraulic control valve of FIG. 1; and

fig. 5 shows a schematic configuration of the hydraulic control system of the present invention.

Description of reference numerals:

10. a valve body; 11. an oil inlet; 12. an oil discharge port; 13. a first working oil port; 14. a second working oil port; 20. a first valve spool; 21. a first through hole; 22. a second through hole; 23. a third through hole; 24. Positioning a step; 30. an accommodating chamber; 31. a first stage; 32. a second stage; 40. a second valve core; 41. A flow through groove; 42. a first force-bearing surface; 43. a second force-bearing surface; 44. a communicating hole; 50. an elastic member; 60. a blocking member; 70. a guide structure; 100. a hydraulic control valve; 200. a hydraulic pump; 300. a directional control valve; 400. a bypass valve; 500. a hydraulic cylinder; 600. a pilot control handle; 700. and the interface overflow valve.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; 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 meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

As shown in fig. 1 to 3, the hydraulic control valve in the present embodiment includes a valve body 10, a first spool 20, and a second spool 40. The respective structures are described in detail below:

as shown in fig. 1 to 3, the valve body 10 is provided with an oil inlet 11, an oil discharge port 12, a first working oil port 13, and a second working oil port 14. The first working oil port 13 is used for communicating with a rodless cavity of the controlled cylinder body, and the second working oil port 14 is used for communicating with a rod cavity of the controlled cylinder body. Specifically, the oil inlet 11 is connected to an oil pump, the oil discharge port 12 is connected to a tank, and the oil inlet 11 and the oil discharge port 12 are also referred to as a "P" port and a "T" port in the related art. In order to facilitate the illustration of the structure of the valve core, only partial structures of two ends of the valve body 10 of the control valve are illustrated in this embodiment, it should be noted that the valve body of the hydraulic control valve is the prior art, and the structure of the valve body of the hydraulic control valve in chinese patent with publication No. CN102947599 can be referred to, so that those skilled in the art can understand the structure of the valve body 10 in this embodiment. Further, the first working oil port 13 is communicated with a rodless cavity of the controlled oil cylinder and used for oil feeding or oil discharging of the rodless cavity, and the second working oil port 14 is communicated with a rod cavity of the controlled oil cylinder and used for oil feeding or oil discharging of the rod cavity. Rodless and rod chambers are also referred to in the art as "large chambers" and "small chambers".

The first valve spool 20 is movably disposed in the valve body 10, and the first valve spool 20 has a first position at which the first working port 13 communicates with the oil discharge port 12 and the second working port 14 communicates with the oil inlet 11, and a second position at which the first working port 13 communicates with the oil inlet 11 and the second working port 14 communicates with the oil discharge port 12. An accommodating cavity 30 is arranged in the first valve core 20, and a first through hole 21, a second through hole 22 and a third through hole 23 which are communicated with the accommodating cavity 30 are arranged on the side wall of the first valve core 20. Specifically, the first valve core 20 can slide in the valve body, and a channel is arranged on the outer wall of the first valve core 20, so that the communication state of the oil inlet 11, the oil discharge port 12, the first working oil port 13 and the second working oil port 14 can be changed when the first valve core 20 is located at different positions. When the first valve core 20 is in the first position, the first working oil port 13 is communicated with the oil discharge port 12, and the second working oil port 14 is communicated with the oil inlet 11, so that oil is fed into the rod cavity, oil is discharged from the rodless cavity, and the push rod of the oil cylinder retracts. When the first valve core 20 is at the second position, the first working oil port 13 is communicated with the oil inlet 11 and the second working oil port 14 is communicated with the oil outlet 12, at the moment, oil is fed into the rodless cavity, oil is discharged from the rod cavity, and the push rod of the oil cylinder extends out. In fig. 1, the position of the first spool 20 is the second position. The first valve core 20 in this embodiment is a hollow structure, i.e. forms the above-mentioned accommodating cavity 30, and the side wall of the first valve core 20 is provided with a first through hole 21, a second through hole 22 and a third through hole 23, the functions of which will be described below.

The second valve spool 40 is movably disposed in the accommodation chamber 30, and the second valve spool 40 has a communication position where the second through hole 22 and the third through hole 23 communicate, and an isolation position where the second through hole 22 and the third through hole 23 are isolated. When the first valve core 20 is at the second position, the first through hole 21 is communicated with the first working oil port 13, the second through hole 22 is communicated with the second working oil port 14, and the third through hole 23 is communicated with the oil discharge port 12, so that the pressure of the rodless cavity in the controlled cylinder is communicated with the accommodating cavity 30, and the second valve core 40 is driven to move from the isolation position to the communication position. Specifically, the second valve core 40 slides in the accommodation chamber 30, and can communicate or isolate the second through hole 22 and the third through hole 23 of the first valve core 20 during the sliding. When the second valve core 40 is in the second position, that is, when the cylinder rod extends as described above, the first through hole 21 is communicated with the first working oil port 13, the second through hole 22 is communicated with the second working oil port 14, and the third through hole 23 is communicated with the oil discharge port 12. In the above-described communication state, the hydraulic oil of the rodless chamber of the controlled cylinder can enter the accommodating chamber 30 along the first working oil port 13 and the first through hole 21. The pressure provided by the hydraulic oil entering the receiving chamber 30 drives the second spool 40 to slide, thereby moving the second spool 40 from the isolation position to the communication position. When the second valve spool 40 is in the communication position, it is possible to provide an additional oil return passage to the rod chamber of the controlled cylinder. Specifically, on the one hand, the oil return of the hydraulic oil in the rod cavity is realized through the passage between the valve body 10 and the first valve core 20, and on the other hand, the oil return of the hydraulic oil in the rod cavity can also be realized through the second working oil port 14, the second through hole 22, the third through hole 23 and the oil discharge port 12, that is, the hydraulic oil in the rod cavity returns oil through two passages at the same time, so that the oil return speed of the rod cavity is increased, and the action force of the oil cylinder is improved. It should be noted that, when the first valve spool 20 is not in the second position, the first through hole 21 is not communicated with the first working fluid port 13, so that the second valve spool 40 is not in the communication position and separates the second through hole 22 from the third through hole 23, thereby not affecting other actions of the cylinder.

According to the above structure, with the technical solution of this embodiment, when the controlled cylinder is in heavy load operation, the first valve core 20 is in the second position, at this time, the first working oil port 13 is communicated with the oil inlet 11 to enable the rod cavity of the controlled cylinder to feed oil, and the second working oil port 14 is communicated with the oil outlet 12 to enable the rod cavity of the controlled cylinder to discharge oil. Meanwhile, the first through hole 21 is communicated with the first working oil port 13, so that the hydraulic oil in the rodless chamber enters the accommodating chamber 30 and pushes the second spool 40 to move to the communication position. After the second valve core 40 is in the communication position, the second through hole 22 and the third through hole 23 are communicated by the second valve core 40, so that the hydraulic oil in the rodless cavity can be discharged from the second working oil port 14, the second through hole 22, the third through hole 23 and the oil discharge port 12, an additional oil discharge channel is also added, the oil return speed is increased, and the cylinder action force is enhanced. The technical effect of increasing the oil discharge channel with the rod cavity is achieved only by improving the control valve of the controlled oil cylinder, and then an external valve block or a cartridge valve does not need to be additionally added in the hydraulic control system, so that the structure of the hydraulic control system is simplified, the cost is reduced, and the limitation caused by the installation space of equipment is reduced. Therefore, the technical scheme of the embodiment overcomes the defects of complex structure, large installation limit and high cost of the hydraulic system in the prior art.

As shown in fig. 3, in the solution of the present embodiment, a flow passing groove 41 is provided on a side wall of the second valve core 40, when the second valve core 40 is in the communication position, both the second through hole 22 and the third through hole 23 are communicated with the flow passing groove 41, and when the second valve core 40 is in the isolation position, the second through hole 22 and/or the third through hole 23 are misaligned with the flow passing groove 41. Specifically, the above-described relief groove 41 is formed concavely in the surface of the second valve body 40, and the relief groove 41 extends in the axial direction of the second valve body 40. Fig. 3 shows the second valve spool 40 in the isolated position, where only the second through-hole 22 corresponds to the transfer groove 41, and the third through-hole 23 is engaged with the inner wall of the second valve spool 40, so that the second through-hole 22 is disconnected from the third through-hole 23. When the second valve core 40 moves rightwards to an open position, the second through hole 22 and the third through hole 23 are both communicated with the overflowing groove 41, at the moment, the second through hole 22 is communicated with the third through hole 23, and therefore return oil of the rodless cavity can flow back to the oil tank through the second through hole 22 and the third through hole 23. It should be noted that when the second valve core 40 is at the isolation position, the overflow groove 41 may be misaligned with the second through hole 22, or the overflow groove 41 may be misaligned with both the second through hole 22 and the third through hole 23.

As shown in fig. 3 and 4, in the solution of the present embodiment, the number of the third through holes 23 is plural, and the plural third through holes 23 are provided at intervals in the axial direction of the first valve body 20. Wherein at least one third through hole 23 of the plurality of third through holes 23 is in communication with the transfer groove 41 when the second valve spool 40 is in the communication position. Particularly, the structure has the technical effect of automatically controlling the oil return amount of the rod cavity of the oil cylinder. In the prior art of the oil return control valve, the control mode is that a sensor detects the pressure of a rodless cavity of an oil cylinder and feeds the pressure back to a controller, and then the controller detects that the pressure of the rodless cavity reaches a fixed value and sends a signal to an electromagnetic valve to control the movement of the oil return control valve. The control mode of the oil return valve is complicated, and elements such as a battery valve, a sensor, a rubber tube, a wire harness and the like are additionally arranged, so that the cost of the system is increased; and the failure rate of the electromagnetic valve, the sensor, the wire harness and the like is high, and the troubleshooting is not easy. In the present embodiment, as can be seen from fig. 3 and 4, as the distance of the second valve core 40 moving to the right is different, the number of the second through holes 22 and the third through holes 23 communicating with each other is also different, and thus the oil return amount of the rod chamber of the cylinder is also different. The moving distance of the second valve core 40 is determined according to the pressure (i.e. pilot pressure) of the rodless cavity of the cylinder, the second valve core 40 gradually moves rightwards along with the change of the pilot pressure, and at the moment, the effective opening areas of the third through holes 23 change along with the movement of the lifting valve core, so that the oil return amount of the rodless cavity of the cylinder is controlled. Through the design of above-mentioned combination hole mode can effectually solve the problem among the above-mentioned prior art, rationally improve hydro-cylinder action strength.

It should be noted that, since the number of the third through holes 23 in the present embodiment is plural, the above-mentioned communication position does not mean that the second valve body 40 is only at a stationary position, but is a continuous position formed along a path through which the plurality of third through holes 23 pass.

As shown in fig. 4, in the solution of the present embodiment, the hole diameters of the plurality of third through holes 23 gradually increase in a direction away from the second through hole 22. Specifically, as can be seen from fig. 4, the diameters of the plurality of third through holes 23 gradually increase in the left-to-right direction, forming a combined hole structure. In this embodiment, the third through holes 23 are three, and the sizes of the apertures of the third through holes 23 are sequentially arranged from small to large. The oil in the rodless cavity of the oil cylinder of the embodiment is used as a pilot, the opening and the movement of the second valve core 40 are accurately controlled through the pressure reduction effect of the second valve core 40, namely after the oil pressure in the rodless cavity of the oil cylinder reaches the opening pressure of the second valve core 40, at this time, along with the continuous increase or decrease of the oil pressure in the rodless cavity of the oil cylinder, the displacement of the second valve core 40 is continuously increased or decreased, namely different oil pressure forces correspond to different strokes of the second valve core 40, and at this time, the effective areas (i.e., the areas exposed by the combined holes) of the plurality of third through holes 23 are continuously changed according to the pressure in the rod cavity of the oil cylinder, so as to control the amount of the oil returned by the rod cavity of the oil cylinder, namely, the back pressure of the oil returned.

As shown in fig. 3, in the present embodiment, the second valve core 40 divides the accommodation chamber 30 into the first section 31 and the second section 32, and the first through hole 21 communicates with the first section 31. The second valve element 40 includes a first force-receiving surface 42 facing the first stage 31 and a second force-receiving surface 43 facing the second stage 32, and the second valve element 40 further includes a communication hole 44, the communication hole 44 communicating the first stage 31 and the second stage 32. Wherein the area of the first force-bearing surface 42 is larger than the area of the second force-bearing surface 43. Specifically, when the first spool 20 is in the first position, the hydraulic oil in the rodless chamber of the cylinder flows into the accommodating chamber 30, and the hydraulic oil flows into the first section 31 first and then flows into the second section 32 through the communication hole 44. At this time, both the left and right ends of the second spool 40 are pushed by the hydraulic oil, but the second spool 40 moves to the right (i.e., toward the communication position) because the first force receiving surface 42 has a larger area than the second force receiving surface 43. The above structure is provided for the purpose of enhancing the control of the moving stroke of the second valve spool 40, specifically: under a heavy-load working condition, the pressure of the rod cavity of the oil cylinder is higher, and the pilot pressure for pushing open the second valve core 40 is higher, at this time, if the acting force of the hydraulic oil in the rod cavity of the oil cylinder is completely acted on the left side of the second valve core 40, the second valve core 40 can be instantly and completely opened (namely instantly moved to the right to the limit position) under the action of the pressure of the rod cavity of the oil cylinder, and the control of the second valve core 40 is extremely difficult. In order to better control the movement of the second valve core 40, the quantity of oil returned by the rod cavities of the oil cylinder is reasonably controlled, and the working force of the oil cylinder is improved. In the present embodiment, as shown in fig. 3, the first small chamber is provided at the left side of the second valve element 40, the effective area at the left side of the second valve element is a1 (i.e. the effective area of the first force-bearing surface 42), the high-pressure oil in the rod chamber of the oil cylinder is acted on from the first through hole 21, and because the pressure of this part of the oil is high (assumed to be P1), if the part of the oil is directly acted on the left end of the second valve element 40, the second valve element 40 is opened in a full stroke, and the control is not performed. In order to enhance the stroke control of the second valve member 40, the second valve member 40 has a communication hole 44 formed therein and a second small chamber formed therein, and the effective area of the second small chamber is a2 (i.e., the effective area of the second force receiving surface 43). The opening pressure of the second valve spool 40 is P1 × (a1-a2), i.e., the pre-load of a spring (described below), which is much less than P1 × a 1. At this time, the displacement of the second valve core 40 can be accurately controlled by adjusting the area difference between the a1 and the a2, and further the exposed area of the combination hole (the third through holes 23) can be controlled, so that the oil quantity of the oil returned from the rod cavity can be controlled, and the action force of the oil cylinder can be better controlled. Compared with the traditional external valve block, the structure saves a control valve block, an electromagnetic valve, a sensor, a rubber tube and the like, greatly reduces the cost, saves the space and has higher practical significance.

It should be noted that the essence of the above structure is that the communication hole 44 is provided to allow the hydraulic oil to simultaneously press the left side and the right side of the second valve core 40, and the difference between the force-receiving area on the left side (i.e. the first force-receiving surface 42) and the force-receiving area on the right side (i.e. the second force-receiving surface 43) of the second valve core 40 is designed to control the moving speed of the second valve core 40. Therefore, those skilled in the art can design other modified structures based on the above principle on the structure of the present embodiment, and the structure is not limited to the above-mentioned structures of the first chamber and the second chamber.

As shown in fig. 3, in the present embodiment, an elastic member 50 is provided between the second spool 40 and the first spool 20, and the elastic member 50 applies an elastic force to the second spool 40 in a direction toward the first through hole 21. Specifically, the elastic member 50 functions such that, when the first through hole 21 is not communicated with the first hydraulic port 13, that is, the left end of the second valve spool 40 is not driven by the hydraulic oil, the elastic force of the elastic member 50 drives the second valve spool 40 to move from the communication position to the isolation position and maintain the position. Specifically, when the first spool 20 is not in the second position, the second through hole 22 and the third through hole 23 need to be disconnected, and further, the second through hole 22 and the third through hole 23 need to be prevented from being communicated with each other and affecting other control operations of the hydraulic control valve. Further, the elastic pre-load force of the elastic element is designed to be the opening pressure of the second valve spool 40, i.e. P1 × (a1-a2) (i.e. the pressure of the rodless chamber of the cylinder multiplied by the difference between the first force-bearing surface 42 and the second force-bearing surface 43).

As shown in fig. 1 and 3, in the present embodiment, the end portion of the first valve body 20 is provided with the blocking piece 60, the elastic piece 50 is a spring, and both ends of the spring are respectively provided in contact with the second valve body 40 and the blocking piece 60. Specifically, the stopper 60 is a plug provided at the right end of the first valve body 20, and a spring is provided in the second section 32 of the accommodating chamber 30, and the spring applies an elastic force toward the left side toward the second valve body 40.

As shown in fig. 3, in the solution of the present embodiment, a guiding structure 70 is provided between the second spool 40 and the blocking member 60. Specifically, the guide structure 70 functions to ensure that the second valve spool 40 can move along a predetermined linear trajectory. The specific structure of this embodiment is that the plugging member 60 is provided with a convex pillar, the right end of the second valve core 40 is provided with a concave recess, the convex pillar is sleeved in the concave recess, that is, the convex pillar and the concave recess form the above-mentioned guiding structure 70. Further, the space in the recess also forms the above-described second small chamber, that is, the above-described communication hole 44 communicates with the recess on the right side of the second valve body 40.

As shown in fig. 3, in the present embodiment, the inner wall of the first valve body 20 is provided with a positioning step 24, and when the second valve body 40 is at the isolation position, the second valve body 40 abuts against the positioning step 24. Specifically, the above-described blocking piece 60 and the positioning step 24 together define the movement range of the second valve spool 40.

According to the above structure, the hydraulic control valve in the embodiment has the characteristics and advantages that: in the embodiment, when the oil cylinder extends out, the oil in the small cavity of the oil cylinder is regenerated to the large cavity by utilizing the self-weight condition, the oil return back pressure of the small cavity is higher, namely the oil return area is smaller; when the load is large, the back pressure of the large cavity of the oil cylinder rises, and the oil return area of the small cavity is small, so that the oil cylinder cannot act forcedly. The direction control valve is changed into a hollow structure, two groups of small holes (a second through hole 22 and a third through hole 23) are additionally arranged on the side surface of a first valve core 20 of the direction control valve to realize the communication between a rod cavity of the oil cylinder and an oil return oil passage, namely, the oil in the rod cavity of the oil cylinder is accelerated to be quickly reserved in the oil return oil passage of the valve body through an internal hollow valve core (the first valve core 20), the action force of the oil cylinder is increased, and the requirement of the actual working condition is met; a second valve core 40 of the poppet valve core is arranged in the hollow valve core, and the purpose of the second valve core is to control the on-off of the two groups of small holes; the other end of the hollow valve core is communicated with the rodless cavity of the oil cylinder through the additionally arranged small hole (the first through hole 21), namely when the load is increased, the pressure of the rodless cavity of the oil cylinder is increased along with the increase of the load, the pressure oil in the rodless cavity of the oil cylinder enters the hollow valve core through the small hole (the first through hole 21) at the position and acts on the head of the second valve core 40, when the pressure of the oil at the position reaches the set pressure of the spring at the tail part of the second valve core 40, the second valve core 40 is pushed away, and the oil in the rod cavity of the oil cylinder. The mode realizes that the oil cylinder rod cavity accelerates oil return, meets the requirement of improving the strength of the oil cylinder, does not need modes such as an external valve block connecting pipe and the like to realize the oil return speed of the oil cylinder, saves an external control valve block, a solenoid valve, a sensor, a rubber pipe and the like, saves space, and has practical significance

The embodiment further provides a hydraulic control system, which includes the hydraulic control valve 100, and the hydraulic control valve 100 is the hydraulic control valve described above. The working principle of the hydraulic control system in this embodiment is explained below:

in the present embodiment, as can be seen from fig. 5, the schematic diagram of the engineering machine mainly includes a positive flow system working apparatus composed of a hydraulic pump, a first directional control valve (i.e., the hydraulic control valve 100), a second directional control valve (i.e., the directional control valve 300), a bypass valve 400, a hydraulic cylinder 500, a pilot control handle 600, and a plurality of interface relief valves 700. In the working device of the embodiment, when the pilot control handle 600 makes the extending action of the rod cavity of the oil cylinder, the pilot hydraulic oil is transmitted to the two directional control valves, the two directional control valves move rightwards, and the valve cores of the two directional control valves act leftwards. At the same time, corresponding signals are transmitted to the bypass valve 400 at the same time, the valve core of the bypass valve 400 is closed, the oil provided by the hydraulic pump does not return to the oil tank through all the directional control valves, and the oil provided by the hydraulic pump enters the oil cylinder to provide power for the action of the hydraulic pump. At this time, oil is fed into a rodless cavity of the oil cylinder, an oil return tank of the oil cylinder with a rod cavity is provided, due to the gravity action of a piston rod and the fact that the oil return area of the rod cavity is small, the oil return backpressure of the oil cylinder with the rod cavity is high, in order to fully utilize the energy, the flow regeneration one-way valve is arranged in the second direction control valve, and at this time, the oil in the rod cavity of the oil cylinder is regenerated into the rodless cavity of the oil cylinder through the flow regeneration valve, so that the energy is recycled.

When the oil cylinder extends out and the external load is continuously increased, (with reference to fig. 1) because the oil return area of the rod cavity of the oil cylinder is relatively small, the oil return speed of the rod cavity of the oil cylinder is relatively low, so that the oil cylinder is powerless in action, at the moment, the oil pressure of the rodless cavity of the oil cylinder is continuously increased along with the increase of the external load, the pressure can be transmitted to the head of the second valve core 40 through the first through hole 21 formed in the first valve core 20 and the accommodating cavity 30 in the first valve core 20, and the function of the pressure is similar to that of pilot control pressure. When the pressure of the rodless cavity of the oil cylinder reaches the set pressure of the spring, the second valve core 40 is opened, at the moment, one part of oil in the rod cavity returns to the oil return channel through the external groove of the first valve core 20, and the other part of the oil returns to the oil return channel through the second through hole 22 and the combination hole (the combination hole comprises three third through holes 23) on the side surface of the first valve core 20. Namely, the oil in the rodless cavity of the oil cylinder is used as a pilot, the opening and the movement of the lifting valve core are accurately controlled through the pressure reduction effect of the second valve core 40, namely after the oil pressure in the rodless cavity of the oil cylinder reaches the opening pressure of the second valve core 40, at this time, along with the continuous increase or decrease of the oil pressure in the large cavity of the oil cylinder, the displacement of the movement of the second valve core 40 is continuously increased or decreased, namely, different oil pressure forces correspond to different strokes of the second valve core 40, and at this time, the effective areas (namely, the areas exposed out of the combined holes) of the three third through holes 23 are continuously changed according to the pressure in the rod cavity of the oil cylinder, so that the amount of the oil returned by the rod cavity of the oil cylinder is controlled, namely, the back pressure.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.