Pressure compensation valve and hydraulic control system

Abstract

The invention belongs to the technical field of hydraulic valves, and discloses a pressure compensation valve and a hydraulic control system. The pressure compensation valve comprises a valve sleeve, a valve seat and a valve element. An oil inlet hole, an oil return hole and a feedback oil hole are formed in the valve sleeve, a connecting corner is arranged on the inner wall of the valve sleeve, and the connecting corner is located between the oil return hole and the feedback oil hole; the valve seat is connected with the valve sleeve; the valve element is slidably arranged in the valve sleeve in the axial direction so as to block or open the oil return hole, the valve element is provided with a first valve element section and a second valve element section, the first valve element section and the valve seat form a first cavity, an oil passing gap is formed between the first valve element section and the valve seat, and the first cavity and the feedback oil hole are communicated through the oil passing gap; a sealing part is arranged between the first valve element section and the second valve element section and can abut against the connecting corner so as to block a gap, between the oil return hole and the feedback oil hole, between the valve sleeve and the valve element. The pressure compensation valve is good in sealing effect, and hydraulic oil leakage is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic valves, and in particular to a pressure compensating valve and a hydraulic control system. Background Art

[0002] Pressure compensation valves are widely used in the field of engineering machinery. For example, after a forklift lifts the cargo to a preset position, it needs to maintain pressure, that is, it will not drop due to its own gravity. However, the pressure compensation valves in the industry generally have the problem of hydraulic oil leakage, resulting in poor hydraulic control effect.

[0003] Therefore, it is necessary to provide a pressure compensation valve and a hydraulic control system to solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide a pressure compensating valve to solve the problems of poor sealing effect between a valve core and a valve sleeve, and difficulty and high cost in machining the sealing structure.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A pressure compensating valve, comprising:

[0007] A valve sleeve, wherein the valve sleeve is provided with an oil inlet hole, an oil return hole, and a feedback oil hole, and an inner wall of the valve sleeve is provided with a connecting corner, and the connecting corner is located between the oil return hole and the feedback oil hole;

[0008] a valve seat connected to the valve sleeve;

[0009] A valve core is slidably arranged in the valve sleeve along the axial direction to block or open the oil return hole, the valve core has a first valve core section and a second valve core section, the first valve core section and the valve seat form a first chamber, an oil gap is provided between the first valve core section and the valve seat, and the oil gap communicates the first chamber with the feedback oil hole; a sealing portion is provided between the first valve core section and the second valve core section, and the sealing portion can abut against the connecting angle to block the gap between the valve sleeve and the valve core between the oil return hole and the feedback oil hole;

[0010] Preferably, the valve sleeve comprises a first body and a second body connected to each other in the axial direction, the inner diameter of the first body is larger than the inner diameter of the second body, and a connection angle is formed at the connection between the first body and the second body.

[0011] Preferably, the diameter of the first valve core section is greater than the diameter of the second valve core section, the first valve core section and the second valve core section are connected via a tapered section, the outer diameter of one end of the tapered section connected to the first valve core section is greater than the outer diameter of one end of the tapered section connected to the second valve core section, the circumferential surface of the tapered section forms the sealing portion, the first valve core section is located in the first main body, and the second valve core section is slidingly guided in cooperation with the second main body.

[0012] Preferably, along the axial direction of the valve core, the oil gap is provided in the form of an annular cavity between the valve core and the valve seat, and a single-side dimension of the oil gap is 0.2-0.5 mm.

[0013] Preferably, it includes an oil passage groove, which is located on the valve seat and / or the valve core. When the oil passage groove is located on the valve seat, the groove wall of the oil passage groove is recessed relative to the inner wall of the valve seat toward a side away from the valve core to form the oil passage gap; when the oil passage groove is located on the valve core, the wall of the oil passage groove is recessed relative to the surface of the valve core toward a side away from the valve seat to form the oil passage gap.

[0014] Preferably, the first valve core section is provided with a one-way throttling channel connected with the first chamber and the feedback oil hole, and a sealing member is provided in the one-way throttling channel, and the sealing member is used to control the one-way flow of the hydraulic oil from the first chamber to the one-way throttling channel.

[0015] Preferably, the one-way throttling channel includes a throttling hole, a accommodating chamber and an oil passage which are connected in sequence, the other end of the throttling hole is connected to the first chamber, the other end of the oil passage is connected to the feedback oil hole, and the sealing member is arranged in the accommodating chamber, and the sealing member is used to disconnect or connect the throttling hole with the accommodating chamber.

[0016] Preferably, the oil passage comprises a first oil passage hole, a second oil passage hole and an annular groove which are connected in sequence; the first oil passage hole is arranged along the axial direction of the valve core, the second oil passage hole is arranged along the radial direction of the valve core, the annular groove is arranged along the circumferential direction of the valve core, and the other end of the first oil passage hole is connected to the accommodating cavity, and the annular groove is connected to both the feedback oil hole and the oil passage gap.

[0017] Preferably, the pressure compensation valve further comprises a plug, wherein the plug is arranged in the first valve core section of the valve core, and the throttling hole and the accommodating chamber are both opened in the plug.

[0018] Another object of the present invention is to provide a hydraulic control system so that the load will not shake when maintained at a certain height, thereby improving the hydraulic control effect.

[0019] To achieve this object, the present invention adopts the following technical solutions:

[0020] A hydraulic control system, comprising:

[0021] A lifting cylinder and a lifting module for controlling the lifting cylinder to perform lifting actions, wherein the lifting module comprises an oil inlet and an oil outlet, and a solenoid valve is arranged between the oil inlet and the oil inlet end of the lifting cylinder;

[0022] A proportional flow valve and a pressure compensating valve as claimed in claim are sequentially arranged between the oil inlet end of the lifting cylinder and the oil outlet, the oil inlet hole of the pressure compensating valve is connected to the proportional flow valve, the oil return hole is connected to the oil outlet, and the feedback oil hole is connected to the oil inlet end of the lifting cylinder.

[0023] Beneficial effects of the present invention:

[0024] The invention discloses a pressure compensating valve. The pressure compensating valve comprises a valve sleeve, a valve seat and a valve core. The valve sleeve is provided with an oil inlet hole, an oil return hole and a feedback oil hole. The inner wall of the valve sleeve is provided with a connecting angle, and the connecting angle is located between the oil return hole and the feedback oil hole; the valve seat is connected to the valve sleeve; the valve core is slidably arranged in the valve sleeve along the axial direction to block or open the oil return hole, and the valve core has a first valve core section and a second valve core section, the first valve core section and the valve seat form a first chamber, and there is an oil gap between the first valve core section and the valve seat, and the oil gap connects the first chamber and the feedback oil hole; a sealing part is provided between the first valve core section and the second valve core section, and the sealing part can abut against the connecting angle to block the gap between the valve sleeve and the valve core between the oil return hole and the feedback oil hole.

[0025] In this pressure compensating valve, when hydraulic oil enters from the feedback oil hole, it pushes the valve core to move from left to right. When the valve core moves to the point where the sealing part abuts the connecting corner, the sealing part and the connecting corner can form a cone seal, thereby effectively sealing the gap between the valve core and the valve sleeve between the return oil hole and the feedback oil hole, thereby effectively avoiding hydraulic oil leakage, and thus producing a good sealing effect. In addition, the processing difficulty and cost are low, and it is easy to produce and use.

[0026] The present invention also discloses a hydraulic control system, including a lifting cylinder and a lifting module for controlling the lifting cylinder to perform lifting actions, the lifting module including an oil inlet and an oil outlet, and an electromagnetic valve is arranged between the oil inlet and the oil inlet end of the lifting cylinder; a proportional flow valve and a pressure compensation valve as described in the claim are arranged in sequence between the oil inlet end of the lifting cylinder and the oil outlet.

[0027] In this hydraulic control system, the pressure compensation valve has a sealing portion, which can strictly form a cone seal with the connecting corner, thereby avoiding leakage of hydraulic oil, and further making the hydraulic system have good stability when maintaining the load, thereby improving the control effect of the hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a sectional view of the sealing state of the pressure compensation valve provided by the present invention;

[0029] Figure 2 is a cross-sectional view of the working state of the pressure compensation valve provided by the present invention;

[0030] Figure 3 It is a schematic diagram of lifting cargo by a hydraulic control system provided by the present invention;

[0031] Figure 4 It is a schematic diagram of the hydraulic control system provided by the present invention for maintaining load.

[0032] In the figure:

[0033] 10. Valve sleeve; 11. Oil inlet hole; 12. Oil return hole; 13. Feedback oil hole; 14. Connection angle; 15. First body; 16. Second body;

[0034] 20. Valve seat;

[0035] 30. valve core; 31. first valve core section; 32. second valve core section; 33. sealing portion; 34. accommodating chamber;

[0036] 41. first chamber; 42. oil gap; 43. second chamber;

[0037] 51, throttle hole; 52, accommodating chamber; 53, oil passage; 531, first oil passage hole; 532, second oil passage hole; 533, annular groove;

[0038] 60. Blocking parts;

[0039] 70. Plug;

[0040] 80. elastic structure; 81. elastic member; 82. mounting member;

[0041] 100. Lifting cylinder;

[0042] 200, solenoid valve;

[0043] 300, proportional flow valve;

[0044] 400. Filter. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0046] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0048] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0049] When a forklift lifts cargo, a proportional valve is usually connected in series with a pressure compensation valve to achieve pressure compensation of the proportional valve, so that the pressure difference between the front and rear ends does not change due to the weight of the load. However, when the load is maintained at a preset height, the gap between the valve core and the valve sleeve will cause hydraulic oil to leak from the gap. If the method of reducing the matching gap between the valve core and the valve sleeve is adopted to ensure sealing, the processing difficulty is large, which greatly increases the manufacturing cost.

[0050] To solve the above problems, Figure 1-Figure 2As shown, this embodiment provides a pressure compensating valve, which is arranged at the rear end of the proportional valve, and the pressure compensating valve includes a valve sleeve 10, a valve seat 20, a valve core 30 and an elastic structure 80; wherein the valve sleeve 10 has an oil inlet hole 11, an oil return hole 12, and a feedback oil hole 13, and the inner wall of the valve sleeve 10 is provided with a connecting corner 14, and the connecting corner 14 is located between the oil return hole 12 and the feedback oil hole 13; the valve seat 20 is connected to the valve sleeve 10; the valve core 30 is slidably arranged in the valve sleeve 10 along the axial direction to block or open the oil return hole 12, and the valve core 30 has a There are a first valve core section 31 and a second valve core section 32, the first valve core section 31 and the valve seat 20 form a first chamber 41, there is an oil gap 42 between the first valve core section 31 and the valve seat 20, the oil gap 42 connects the first chamber 41 and the feedback oil hole 13; a sealing portion 33 is provided between the first valve core section 31 and the second valve core section 32, the sealing portion 33 can abut against the connecting corner 14 to seal the gap between the valve sleeve 10 and the valve core 30 between the return oil hole 12 and the feedback oil hole 13; the elastic structure 80 is provided between the valve sleeve 10 and the second valve core section 32.

[0051] The valve core 30 of this pressure compensation valve is provided with a sealing portion 33. When the hydraulic oil enters through the feedback oil hole 13 and pushes the valve core 30 to move from left to right, the sealing portion 33 will abut against the connecting corner 14, thereby preventing the hydraulic oil entering from the feedback oil hole 13 from flowing out through the return oil hole 12, producing a good sealing effect, so that when the load is maintained, there will be no problem of hydraulic oil leakage.

[0052] Taking a forklift as an example, when the forklift's cargo fork is lifted or lowered, the hydraulic oil usually passes through the one-way valve, solenoid valve or proportional valve in sequence to reach the lifting cylinder, and pushes the cylinder to lift the goods. When the goods are held, the dead weight of the goods acts on the cylinder, generating hydraulic pressure in the oil chamber of the cylinder, and the hydraulic oil in the oil chamber is cut off by the one-way valve, proportional valve and pressure compensation valve, thereby ensuring that the goods are stable in the raised position. When the goods need to be lowered, the solenoid valve is energized, the hydraulic oil returns to the oil tank to complete the lowering action, the proportional valve controls the current to control the lowering speed, and the pressure compensation valve can keep the pressure difference at the opening of the proportional valve basically constant, thereby making the lowering speed unaffected by the load. However, the pressure compensation valve is usually a sliding valve structure, and there will inevitably be a problem of hydraulic oil leakage from the oil return hole 12. In this embodiment, the sealing portion 33 used is abutted against the connecting corner 14, ensuring a good sealing effect, and at the same time, there is no need to use the method of reducing the matching gap between the valve core 30 and the valve sleeve 10 to solve the sealing problem, thereby reducing the overall processing difficulty.

[0053] In addition, if Figure 1-Figure 2As shown, the valve sleeve 10 includes a first body 15 and a second body 16 connected to each other in the axial direction, the inner diameter of the first body 15 is larger than the inner diameter of the second body 16, and the connection between the first body 15 and the second body 16 forms a connection corner 14, that is, the connection corner 14 is a step structure formed by connecting the first body 15 and the second body 16. This structure can simplify the internal structure of the valve sleeve 10, and there is no need to set it separately in the valve sleeve 10. It only needs to form the first body 15 and the second body 16 of different diameters in one piece to form the corresponding connection corner 14, thereby reducing the overall manufacturing and use costs.

[0054] In addition, if Figure 1-Figure 2 As shown, the diameter of the first valve core section 31 is greater than the diameter of the second valve core section 32, the first valve core section 31 and the second valve core section 32 are connected through a tapered section, the outer diameter of the end of the tapered section connected to the first valve core section 31 is greater than the outer diameter of the end of the tapered section connected to the second valve core section 32, and the circumferential surface of the tapered section forms a sealing portion 33. The valve core 30 is coaxially arranged with the valve sleeve 10, the first valve core section 31 is located (slidingly arranged) in the first body 15, and the second valve core section 32 is slidingly guided with the second body 16.

[0055] By setting a conical section to connect the first valve core section 31 and the second valve core section 32, not only the overall structure can be simplified, but also a flat sealing portion 33 can be formed, so that the sealing effect of the abutment with the connection corner 14 is better. It should be noted here that in this embodiment, the sealing portion 33 is a sealing slope, and the sealing slope can abut against the connection corner 14 and form a cone seal. By making the second valve core section 32 and the second body 16 slide and guide, the second valve core section 32 can only slide along the axial direction of the valve sleeve 10, and no sliding will occur, thereby reducing the collision or wear of the valve core 30 and the valve sleeve 10, extending the service life of the pressure compensation valve, and ensuring a good use effect. It should be noted here that the diameter of the second valve core section 32 of the valve core 30 can be slightly smaller than the inner diameter of the second body 16, that is, the difference between the inner diameter of the valve sleeve 10 and the diameter of the second valve core section 32 of the valve core 30 is kept within the tolerance range of 0.01-0.02 mm.

[0056] like Figure 1-Figure 2 As shown, along the axial direction of the valve core 30, the oil gap 42 is an annular cavity disposed between the valve core 30 and the valve seat 20, and the single-side size of the oil gap 42 is 0.2-0.5 mm. That is, the diameter of the first valve core section 31 is 0.4-1 mm smaller than the inner diameter of the first body 15 (0.2-0.5 mm on one side), so that the oil gap 42 is naturally formed between the two, thereby simplifying the overall structure and ensuring that the hydraulic oil can smoothly flow from the oil gap 42 into the first chamber 41 or flow out through the oil gap 42.

[0057] In addition, in other embodiments, the pressure compensation valve further includes an oil passage groove, which is located at the valve seat 20 and / or the valve core 30. When the oil passage groove is located at the valve seat 20, the inner wall of the groove wall of the oil passage groove and the valve seat 20 are recessed toward the side away from the valve core 30 to form an oil passage gap 42; when the oil passage groove is located at the valve core 30, the wall of the oil passage groove is recessed toward the side away from the valve seat 20 relative to the surface of the valve core 30 to form an oil passage gap 42. The oil passage gap 42 formed by this structure can be a groove extending along the axial direction of the valve core 30, or an annular gap. Regardless of the structure, it can ensure that the hydraulic oil flows in the oil passage gap 42, and according to actual needs, it can be selected to have an oil passage groove only in the valve seat 30, or an oil passage groove only in the valve core 30, or a structure in which the oil passage groove is simultaneously provided in the valve seat 20 and the valve core 30, which is not limited in this embodiment.

[0058] In addition, if Figure 1-Figure 2 As shown, the first valve core section 31 is provided with a one-way throttling channel connected with the first chamber 41 and the feedback oil hole 13, and a plugging member 60 is provided in the one-way throttling channel, and the plugging member 60 is used to control the one-way flow of hydraulic oil from the first chamber 41 to the one-way throttling channel. This structure can adjust the opening of the oil return hole 12 according to the change of system pressure, thereby maintaining a constant pressure difference between the front and rear ends of the proportional valve, and ensuring the stability of the operation even when the load changes.

[0059] In this embodiment, if Figure 1-Figure 2As shown, the diameter of the first valve core section 31 is greater than the diameter of the second valve core section 32, and the outer periphery of the first valve core section 31 and the inner wall of the first main body 15 of the valve sleeve 10 form a second chamber 43, and the second chamber 43 is connected to the oil gap 42 through the annular groove 533 (the second chamber 43 is located on the right side of the oil gap 42). The valve seat 20 is arranged at the left end of the valve sleeve 10, the oil inlet hole 11 is arranged at the right end of the valve sleeve 10, the oil return hole 12 and the feedback oil hole 13 are both opened in the circumferential direction of the valve sleeve 10, and the feedback oil hole 13 is located on the left side of the oil return hole 12. The valve core 30 can change the area of ​​the oil return hole 12 blocked in the axial direction to change the opening of the oil return hole 12. When the hydraulic oil passes through the feedback oil hole 13, it will first enter the second chamber 43, and then enter the first chamber 41 through the oil gap 42 and act on the left end of the valve core 30. Assuming that the front end pressure of the proportional valve is F1 and the rear end pressure is F2, the hydraulic oil can flow into the pressure compensation valve from the feedback oil hole 13, and flow into the first chamber 41 through the oil gap 42. Since the feedback oil hole 13 of the pressure compensation valve is connected to the front end of the flow meter, the pressure generated by the hydraulic oil in the first chamber 41 on the first valve core section 31 is F1 at this time; as the hydraulic oil flows into the valve sleeve 10 from the oil inlet hole 11, the hydraulic oil in the valve sleeve 10 will generate a pressure F2 on the second valve core section 32 of the valve core 30, and the remaining part of the hydraulic oil can flow out from the return oil hole 12. Since the elastic structure is arranged between the valve sleeve 10 and the second valve core section 32, it is assumed that the elastic force generated by the elastic structure is F3. It can be understood that when the pressure compensation valve is in a balanced state, F1=F2+F3.

[0060] When the front end load of the fork increases, the descending speed of the fork will also tend to increase. At this time, F1 increases, which increases the flow of hydraulic oil entering the first chamber 41 from the feedback oil hole 13, thereby causing the valve core 30 to move to the right to reduce the opening of the return oil hole 12, thereby reducing the amount of hydraulic oil passing through the return oil hole 12, thereby reducing the descending rate of the fork, that is, ensuring that the fork can still descend at a stable rate.

[0061] When the front-end load of the fork becomes smaller, the descending rate of the fork will also tend to decrease. At this time, F1 becomes smaller, which makes the flow of hydraulic oil entering the first chamber 41 from the feedback oil hole 13 smaller, and then the valve core 30 moves to the left to increase the opening of the return oil hole 12, and then the amount of hydraulic oil passing through the return oil hole 12 increases, so that the descending rate of the fork increases, that is, to ensure that the fork can still descend at a stable rate. At this time, part of the hydraulic oil in the first chamber 41 flows out through the oil gap 42, and part of the hydraulic oil flows into the one-way throttling channel, and breaks the blocking member 60 to flow out from the one-way throttling channel.

[0062] When the load increases, the hydraulic oil flowing in from the feedback oil hole 13 flows into the first chamber 41 through the oil gap 42, thereby slowing down the flow rate of the hydraulic oil flowing into the first chamber 41, thereby slowing down the movement speed of the valve core 30 to the right, and further slowing down the flow change at the return oil hole 12.

[0063] Specifically, Figure 1-Figure 2 As shown, the one-way throttling channel includes a throttling hole 51, a receiving chamber 52 and an oil passage 53 connected in sequence. The other end of the throttling hole 51 is connected to the first chamber 41, and the other end of the oil passage 53 is connected to the feedback oil hole 13. The blocking member 60 is arranged in the receiving chamber 52. The blocking member 60 is used to disconnect or connect the throttling hole 51 with the receiving chamber 52. When the hydraulic oil in the first chamber 41 flows out from the one-way throttling channel, the hydraulic oil first enters the throttling hole 51, and then pushes the blocking member 60 away from the connection between the throttling hole 51 and the receiving chamber 52, so that the hydraulic oil enters the oil passage 53 through the receiving chamber 52, and finally is discharged from the feedback oil hole 13 through the oil passage 53. The setting of the throttling hole 51 can limit the flow rate of the hydraulic oil, thereby playing a good throttling role. The setting of the blocking member 60 ensures that the hydraulic oil can only flow in one direction and cannot enter the throttling hole 51 from the oil passage 53.

[0064] It should be noted that, in this embodiment, the blocking member 60 is a steel ball. The steel ball has a simple structure, is easy to produce, and has the characteristics of high hardness, good wear resistance and corrosion resistance. The steel ball is selected to block the one-way throttling channel, which is not only easy to install, but also has a good one-way flow effect.

[0065] In addition, if Figure 1-Figure 2 As shown, the oil passage 53 includes a first oil passage hole 531, a second oil passage hole 532 and an annular groove 533 which are connected in sequence; the first oil passage hole 531 is arranged along the axial direction of the valve core 30, the second oil passage hole 532 is arranged along the radial direction of the valve core 30, and the annular groove 533 is arranged along the circumferential direction of the valve core 30. The other end of the first oil passage hole 531 is connected to the accommodating chamber 52, and the annular groove 533 is connected to the feedback oil hole 13 and the oil passage gap 42. This arrangement enables the first oil passage hole 531 opened in the axial direction to cooperate with the second oil passage hole 532 opened in the radial direction and the annular groove 533 arranged along the outer circumference, which not only simplifies the overall structure, but also enables the hydraulic oil to flow smoothly in the oil passage 53 without generating excessive pressure loss and flow resistance, thereby ensuring a good use effect.

[0066] In addition, if Figure 1-Figure 2As shown, the pressure compensation valve further includes a plug 70, which is disposed on the first valve core section 31 of the valve core 30, and the throttle hole 51 and the accommodating chamber 52 are both provided in the plug 70. As an independent part, the plug 70 can be individually precision machined to ensure the dimensional accuracy of the throttle hole 51 and the accommodating chamber 52, and it is more convenient to place the plugging member 60 in the accommodating chamber 52; if the throttle hole 51 and the accommodating chamber 52 are blocked or other problems, it is only necessary to directly replace the plug 70 without replacing the entire valve core 30; at the same time, it also reduces the processing cost and assembly difficulty, and facilitates subsequent maintenance and replacement.

[0067] It should be noted here that, in this embodiment, Figure 1-Figure 2 As shown, the valve core 30 is provided with a receiving groove, the receiving groove is used to receive the plug 70, and the inner wall of the receiving groove is provided with a thread, and the plug 70 can be threadedly connected to the receiving groove of the valve core 30. Through the threaded connection, the plug 70 can be stably fixed in the receiving groove of the valve core 30, and is not easy to loosen or fall off; and the threaded connection is also convenient for subsequent maintenance and replacement. If problems such as blockage occur, the plug 70 can be easily removed to facilitate the replacement or repair of parts and improve maintenance efficiency. It is further explained that in other embodiments, the plug 70 can also be fixed by clamping or by a locking member, and no other limitations are made in this embodiment.

[0068] In addition, if Figure 1-Figure 2 As shown, the elastic structure 80 also includes an elastic member 81 and a mounting member 82. The mounting member 82 is disposed in the valve sleeve 10. One end of the elastic member 81 abuts against the second valve core section 32, and the other end is connected to or abuts against the mounting member 82. The elastic member 81 can ensure that the valve core 30 can move to a desired position under different pressures, thereby changing the size of the sealing area of ​​the oil return hole 12; the mounting member 82 provides a stable support effect for the elastic member 81, and also facilitates the installation of the elastic member 81.

[0069] It should be noted that, in this embodiment, the elastic member 81 is a spring. The structure of the spring is simple and inexpensive, and is easy to produce and manufacture, which is conducive to reducing costs. In addition, the mounting member 82 is provided with a through hole along its axial direction, so that the hydraulic oil entering from the oil inlet hole 11 can enter the valve sleeve 10 through the through hole, thereby ensuring the subsequent hydraulic effect.

[0070] In addition, if Figure 1-Figure 2 As shown, the second valve core section 32 of the valve core 30 is provided with an accommodating cavity 34, and at least a portion of the elastic member 81 extends into the accommodating cavity 34 and abuts against the bottom of the accommodating cavity 34. By providing the accommodating cavity 34 inside the valve core 30 to accommodate the elastic member 81, not only the external dimensions of the entire pressure compensation valve can be reduced, but also the compactness of the internal structure of the valve body can be ensured.

[0071] like Figure 3-Figure 4As shown, the present embodiment further provides a hydraulic control system, which includes a lifting cylinder 100 and a lifting module for controlling the lifting cylinder 100 to perform lifting actions, the lifting module includes an oil inlet and an oil outlet, and a solenoid valve 200 is arranged between the oil inlet and the oil inlet end of the lifting cylinder 100; a proportional flow valve 300 and the above-mentioned pressure compensation valve are arranged in sequence between the oil inlet end and the oil outlet of the lifting cylinder 100, the oil inlet hole 11 of the pressure compensation valve is connected to the proportional flow valve 300, the oil return hole 12 is connected to the oil outlet, and the feedback oil hole 13 is connected to the oil inlet end of the lifting cylinder 100.

[0072] like Figure 3 As shown, when the cargo needs to be lifted, the hydraulic oil at the oil inlet (P port) reaches the lifting cylinder 100 through the solenoid valve 200, thereby completing the lifting action. When the cargo needs to be lowered, the proportional flow valve 300 is energized, and the hydraulic oil in the lifting cylinder 100 returns to the oil tank through the proportional flow valve 300 and the pressure compensation valve through the oil outlet (T port), thereby completing the lowering action. In this process, the proportional flow valve 300 can control the lowering speed of the cargo by controlling the current; the pressure compensation valve can maintain the pressure difference of the proportional flow valve 300 constant through the above structure, so that the lowering speed is not affected by the load weight, thereby ensuring the stability of the lowering process.

[0073] like Figure 4 As shown, when it is necessary to keep the load at a certain height, the hydraulic oil of the lifting cylinder 100 is cut off by the proportional flow valve 300, the pressure compensation valve and the solenoid valve 200 in the closed state; the pressure compensation valve has a sealing portion 33, which can strictly form a cone seal with the connecting corner 14, thereby avoiding leakage of the hydraulic oil, and thus making the hydraulic system have good stability when holding the load. At the same time, since the pressure compensation valve has a one-way throttling channel, it can also maintain the stability of the positive valve core 30 during pressure compensation, and the use effect is good.

[0074] It should be noted here that, in this embodiment, a filter screen 400 is also provided between the solenoid valve 200 and the proportional flow valve 300. The filter screen 400 can effectively filter out fine impurities in the hydraulic oil, thereby preventing the fine impurities from clogging small holes or flow channels, and also preventing damage to other equipment during the circulation process, thereby ensuring good hydraulic circulation and extending the service life of the equipment.

[0075] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A pressure compensating valve, characterized in that: include: A valve sleeve (10), the valve sleeve (10) having an oil inlet hole (11), an oil return hole (12), and a feedback oil hole (13); an inner wall of the valve sleeve (10) is provided with a connecting corner (14), and the connecting corner (14) is located between the oil return hole (12) and the feedback oil hole (13); A valve seat (20) connected to the valve sleeve (10); A valve core (30) is slidably arranged in the valve sleeve (10) along the axial direction to block or open the oil return hole (12). The valve core (30) has a first valve core section (31) and a second valve core section (32). The first valve core section (31) and the valve seat (20) form a first chamber (41). An oil gap (42) is provided between the first valve core section (31) and the valve seat (20). The oil gap (42) communicates with the first chamber (41) and the feedback oil hole (13). A sealing portion (33) is provided between the first valve core section (31) and the second valve core section (32). The sealing portion (33) can abut against the connecting corner (14) to block the gap between the valve sleeve (10) and the valve core (30) between the oil return hole (12) and the feedback oil hole (13).

2. The pressure compensating valve according to claim 1, characterized in that: The valve sleeve (10) comprises a first body (15) and a second body (16) which are connected to each other in the axial direction, the inner diameter of the first body (15) is larger than the inner diameter of the second body (16), and a connection angle (14) is formed at the connection between the first body (15) and the second body (16).

3. The pressure compensating valve according to claim 2, characterized in that: The diameter of the first valve core section (31) is greater than the diameter of the second valve core section (32); the first valve core section (31) and the second valve core section (32) are connected via a conical section; the outer diameter of one end of the conical section connected to the first valve core section (31) is greater than the outer diameter of one end of the conical section connected to the second valve core section (32); the circumferential surface of the conical section forms the sealing portion (33); the first valve core section (31) is located in the first main body (15); and the second valve core section (32) is slidably guided in cooperation with the second main body (16).

4. The pressure compensating valve according to claim 3, characterized in that: Along the axial direction of the valve core (30), the oil gap (42) is arranged in the form of an annular cavity between the valve core (30) and the valve seat (20), and the single-side size of the oil gap (42) is 0.2-0.5 mm.

5. The pressure compensating valve according to claim 3, characterized in that: The invention comprises an oil passage groove, wherein the oil passage groove is located on the valve seat (20) and / or the valve core (30). When the oil passage groove is located on the valve seat (20), the groove wall of the oil passage groove is recessed relative to the inner wall of the valve seat (20) toward a side away from the valve core (30) to form the oil passage gap (42); when the oil passage groove is located on the valve core (30), the wall of the oil passage groove is recessed relative to the surface of the valve core (30) toward a side away from the valve seat (20) to form the oil passage gap (42).

6. The pressure compensating valve according to claim 1, characterized in that: The first valve core section (31) is provided with a one-way throttling channel connected to the first chamber (41) and the feedback oil hole (13), and a blocking member (60) is provided in the one-way throttling channel, and the blocking member (60) is used to control the one-way flow of hydraulic oil from the first chamber (41) to the one-way throttling channel.

7. The pressure compensating valve according to claim 6, characterized in that: The one-way throttling passage comprises a throttling hole (51), a receiving chamber (52) and an oil passage (53) which are connected in sequence. The other end of the throttling hole (51) is connected to the first chamber (41), and the other end of the oil passage (53) is connected to the feedback oil hole (13). The blocking member (60) is arranged in the receiving chamber (52), and the blocking member (60) is used to disconnect or connect the throttling hole (51) and the receiving chamber (52).

8. The pressure compensating valve according to claim 7, characterized in that: The oil passage (53) comprises a first oil passage hole (531), a second oil passage hole (532) and an annular groove (533) which are connected in sequence; the first oil passage hole (531) is arranged along the axial direction of the valve core (30), the second oil passage hole (532) is arranged along the radial direction of the valve core (30), the annular groove (533) is arranged along the circumferential direction of the valve core (30), and the other end of the first oil passage hole (531) is connected to the accommodating chamber (52), and the annular groove (533) is connected to both the feedback oil hole (13) and the oil passage gap (42).

9. The pressure compensating valve according to claim 8, characterized in that: The pressure compensation valve further comprises a plug (70), wherein the plug (70) is arranged in the first valve core section (31) of the valve core (30), and the throttle hole (51) and the accommodating chamber (52) are both opened in the plug (70).

10. A hydraulic control system, characterized in that: include: A lifting cylinder (100) and a lifting module for controlling the lifting cylinder (100) to perform lifting actions, wherein the lifting module comprises an oil inlet and an oil outlet, and a solenoid valve (200) is arranged between the oil inlet and the oil inlet end of the lifting cylinder; A proportional flow valve (300) and a pressure compensation valve as described in any one of claims 1 to 9 are sequentially arranged between the oil inlet end and the oil outlet of the lifting cylinder (100); the oil inlet hole (11) of the pressure compensation valve is connected to the proportional flow valve (300), the oil return hole (12) is connected to the oil outlet, and the feedback oil hole (13) is connected to the oil inlet end of the lifting cylinder (100).

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