Pressure compensation valve

Abstract

The utility model belongs to the technical field of hydraulic valves, and discloses a pressure compensation valve which comprises a valve sleeve, a valve element, a valve seat and an elastic unit, the valve sleeve is provided with an oil inlet, an oil return port and a feedback oil port, the valve seat is arranged at one end of the valve sleeve, the valve element is arranged in the valve sleeve in a sliding mode in the axial direction, and the valve element is provided with a first end and a second end. A cavity is formed between the end portion of the first end and the valve seat, an oil passing gap is formed between the peripheral side of the first end and the valve sleeve and communicates with the cavity and the feedback oil port, the first end is provided with a one-way throttling channel communicating with the cavity and the feedback oil port, and a plugging piece is arranged in the one-way throttling channel. The plugging piece is used for controlling one-way flow of hydraulic oil from the cavity to the feedback oil port, and the elastic unit is elastically arranged between the valve sleeve and the second end of the valve element. When the load change is large, the stable rate can still be ensured by applying the pressure compensation valve, and the problem of system jitter caused by pressure step and the like can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic valves, in particular to a pressure compensating valve. Background Art

[0002] Pressure-compensating valves are widely used in construction machinery. For example, in a forklift's descent control circuit, it's desirable to maintain the fork's descent rate constant despite the weight of the cargo. However, since the flow rate through a flow control valve, when the throttle opening is constant, is affected by changes in the load (i.e., the weight of the cargo), the fork's movement rate cannot be maintained constant. Therefore, a pressure-compensating valve is typically installed in series with the flow control valve to compensate for the pressure difference between its front and rear ends, ensuring that the pressure difference between the front and rear ends remains constant despite the weight of the cargo.

[0003] However, when the load suddenly changes and increases, the pressure of the input pressure compensation valve will change in a step, causing the valve core of the pressure compensation valve to change suddenly larger, which in turn causes the output flow to be unstable, resulting in system jitter and other problems.

[0004] Therefore, it is necessary to provide a pressure compensating valve to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide a pressure compensating valve, which can ensure rate stability when the load changes greatly, and can reduce problems such as system jitter caused by pressure steps.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A pressure compensating valve, comprising:

[0008] A valve sleeve, wherein the valve sleeve has an oil inlet, an oil return port and an oil feedback port;

[0009] A valve core and a valve seat, wherein the valve seat is provided at one end of the valve sleeve, and the valve core is slidably provided in the valve sleeve along the axial direction. The valve core has a first end and a second end, a chamber is formed between the end of the first end and the valve seat, an oil gap is defined between the circumference of the first end and the valve sleeve, and the oil gap communicates with the chamber and the feedback oil port. The first end is provided with a one-way throttling passage communicating with the chamber and the feedback oil port, and a blocking member is provided in the one-way throttling passage, and the blocking member is used to control the one-way flow of hydraulic oil from the chamber to the feedback oil port;

[0010] The elastic unit is arranged between the valve sleeve and the second end.

[0011] Preferably, the one-way throttling channel includes a throttling hole, a receiving hole and an oil passage connected in sequence, the throttling hole is connected to the chamber, the oil passage is connected to the feedback oil port, and the sealing member is arranged in the receiving hole, and the sealing member is used to disconnect or connect the throttling hole and the receiving hole.

[0012] Preferably, the valve core is provided with a first oil hole in the axial direction, the valve core is provided with a second oil hole in the radial direction, and the valve core is provided with an annular groove in the circumferential direction. The first oil hole, the second oil hole and the annular groove are connected in sequence to form the oil passage. The first oil hole is connected to the accommodating hole, and the annular groove is connected to the feedback oil port and the oil gap.

[0013] Preferably, the pressure compensating valve further comprises a plug, which is disposed in the first end of the valve core, and the throttling hole and the accommodating hole are opened in the plug.

[0014] Preferably, the plug is detachably connected to the valve core.

[0015] Preferably, the plug is threadedly connected to the valve core.

[0016] Preferably, the diameter of the first end of the valve core is smaller than the inner diameter of the valve sleeve to form the oil-passing gap, and the second end of the valve core is in sliding guide cooperation with the valve sleeve.

[0017] Preferably, the valve core and the valve sleeve are slidingly guided together, and the first end of the valve core is provided with an oil passing groove along the axial direction to form the oil passing gap.

[0018] Preferably, the elastic unit includes an elastic member and a mounting seat, one end of the elastic member abuts against the second end of the valve core, and the other end is arranged on the mounting seat and abuts against the mounting seat, and the mounting seat is fixedly arranged in the valve sleeve.

[0019] Preferably, a receiving cavity is formed at the second end of the valve core, and the elastic member extends into the receiving cavity and abuts against the bottom of the cavity.

[0020] Beneficial effects of the utility model:

[0021] The cam is secured to the cam face and is adapted to engage a plurality of check valves and a plurality of check valves, and the check valves are secured to the cam face and are adapted to engage a plurality of check valves and a plurality of check valves.

[0022] This pressure-compensating valve automatically adjusts the opening of the return port based on system pressure changes, maintaining a constant pressure differential between the front and rear ends of the flow control valve. This ensures smooth operation even when the load changes. In this case, the fork's lowering rate remains stable. When the fork's front end load increases, the fork's lowering rate tends to increase. At this time, the hydraulic oil pressure entering the chamber through the feedback port increases, causing the valve core to move rightward, reducing the opening of the return port. This reduces the hydraulic oil flow at the return port, thus reducing the fork's lowering rate, allowing the fork to continue to descend at a stable rate. When the fork's front end load decreases, the fork's lowering rate tends to decrease. At this time, the hydraulic oil pressure entering the chamber through the feedback port decreases, causing the valve core to move leftward, increasing the opening of the return port. This increases the hydraulic oil flow at the return port, thus increasing the fork's lowering rate, allowing the fork to continue to descend at a stable rate. At this time, most of the hydraulic oil in the chamber flows into the one-way throttling channel and pushes open the blocking piece to flow out of the one-way throttling channel; at the same time, a small part of the hydraulic oil flows out through the oil gap.

[0023] When the load increases, the hydraulic oil flowing into the feedback oil port flows into the chamber through the oil gap, slowing down the flow rate of the hydraulic oil into the chamber, thereby slowing down the rate at which the valve core moves to the right, and thus slowing down the flow change at the return oil port. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a cross-sectional schematic diagram of the pressure compensating valve provided in the first embodiment of the present utility model;

[0025] Figure 2 It is a cross-sectional schematic diagram of the pressure compensation valve provided in the second embodiment of the present utility model.

[0026] In the picture:

[0027] 1. Valve sleeve; 11. Oil inlet; 12. Oil return port; 13. Feedback oil port;

[0028] 2. Valve core; 21. First end; 211. Oil groove; 22. Second end; 23. Accommodation chamber;

[0029] 31. Chamber; 32. Oil gap;

[0030] 4. Sealing parts;

[0031] 51. Elastic member; 52. Mounting seat;

[0032] 61, throttle hole; 62, accommodating hole; 631, first oil hole; 632, second oil hole; 633, annular groove;

[0033] 7. Plug;

[0034] 8. Valve seat. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0036] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0037] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0038] In the description of this embodiment, the terms "upper," "lower," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0039] In a control loop, a pressure compensating valve is typically installed in series with the flow control valve to compensate for the pressure. This ensures that the pressure differential between the front and rear ends of the flow control valve remains constant despite load fluctuations. However, when the load fluctuates significantly, the pressure input to the pressure compensating valve changes dramatically, leading to unstable output flow and, consequently, unstable fork lowering speed.

[0040] In order to solve the above problems, Figure 1 As shown, this embodiment provides a pressure compensating valve, which is arranged at the rear end of the flow control valve. The pressure compensating valve includes a valve sleeve 1, a valve core 2, a valve seat 8 and an elastic unit. The interior of the valve sleeve 1 is hollow, and the valve sleeve 1 has an oil inlet 11, an oil return port 12 and a feedback oil port 13. The feedback oil port 13 is connected to the front end of the flow control valve, and the oil inlet 11 is connected to the rear end of the flow control valve; the valve seat 8 is arranged at one end of the valve sleeve 1, and the valve core 2 is slidably arranged in the valve sleeve 1 along the axial direction. The valve core 2 has A first end 21 and a second end 22, a chamber 31 is formed between the end of the first end 21 and the valve seat 8, an oil gap 32 is provided between the peripheral side of the first end 21 and the valve sleeve 1, the oil gap 32 communicates with the chamber 31 and the feedback oil port 13, the first end 21 is provided with a one-way throttling channel communicated with the chamber 31, a blocking member 4 is provided in the one-way throttling channel, the blocking member 4 is used to control the unidirectional flow of hydraulic oil from the chamber to the one-way throttling channel, the elastic unit is elastically arranged between the valve sleeve 1 and the second end 22 of the valve core 2.

[0041] This pressure compensating valve can automatically adjust the opening of the oil return port 12 according to changes in the system pressure, thereby maintaining a constant pressure difference between the front and rear ends of the flow control valve. Even when the load changes, it can ensure smooth operation. In this embodiment, it also ensures a stable lowering rate of the fork.

[0042] In this embodiment, if Figure 1As shown, the valve seat 8 is arranged at the left end of the valve sleeve 1, the oil inlet 11 is located at the right end of the valve sleeve 1, and the feedback oil port 13 and the return oil port 12 are sequentially opened on the circumference of the valve sleeve 1 from left to right. The valve core 2 slides axially to change the area of ​​the blocked return oil port 12 to change the opening of the return oil port 12. Assuming that the front-end pressure of the flow control valve is F1 and the rear-end pressure is F2, the hydraulic oil can flow into the pressure compensation valve from the feedback oil port 13 and into the chamber 31 through the oil gap 32. Since the feedback oil port 13 of this pressure compensation valve is connected to the front end of the flow control valve, the pressure generated by the hydraulic oil in the chamber 31 on the first end 21 of the valve core 2 is F1; the hydraulic oil flows into the valve sleeve 1 through the oil inlet 11. At this time, the pressure generated by the hydraulic oil in the valve sleeve 1 on the second end 22 of the valve core 2 is F2, and part of the hydraulic oil can flow out through the return oil port 12. Since the elastic unit is elastically arranged between the valve sleeve 1 and the second end 22 of the valve core 2, assuming that the elastic force of the elastic unit is F', it can be understood that: F'+F2=F1, that is, F'=F1-F2.

[0043] When the load at the front end of the fork increases, the fork's descending rate tends to increase. At this time, F1 increases, causing the pressure of the hydraulic oil entering the chamber 31 from the feedback oil port 13 to increase, thereby causing the valve core 2 to move to the right to reduce the opening of the return oil port 12, thereby reducing the hydraulic oil flow at the return oil port 12, and thus reducing the fork's descending rate, so that the fork can still descend at a stable rate.

[0044] When the load on the fork's front end decreases, the fork's descent rate tends to slow. At this point, F1 decreases, reducing the hydraulic oil pressure entering chamber 31 from feedback port 13. This in turn causes valve spool 2 to move leftward, widening the opening of oil return port 12. This increases the flow of hydraulic oil at oil return port 12, increasing the fork's descent rate and maintaining a stable rate of descent. At this point, most of the hydraulic oil in chamber 31 flows into the one-way throttle passage, pushing open the blocking member 4 and allowing it to flow out of the one-way throttle passage. Simultaneously, a small amount of hydraulic oil flows out through oil gap 32.

[0045] When the load increases, the hydraulic oil flowing into the feedback oil port 13 flows into the chamber 31 through the oil gap 32, which slows down the flow rate of the hydraulic oil into the chamber 31, thereby slowing down the rate at which the valve core 2 moves to the right, and further slowing down the flow change at the return oil port 12.

[0046] Specifically, if Figure 1As shown, the one-way throttling channel includes a throttling hole 61, a receiving hole 62 and an oil passage that are connected in sequence. The throttling hole 61 is connected to the chamber 31, and the oil passage is connected to the feedback oil port 13. The blocking member 4 is arranged in the receiving hole 62. The blocking member 4 can open the throttling hole 61 after blocking, so that the throttling hole 61 and the oil passage are disconnected or connected. When the hydraulic oil in the chamber 31 flows out of the one-way throttling channel, the hydraulic oil first enters the throttling hole 61, and then flows out of the receiving hole 62 when the blocking member 4 is pushed open, and then flows into the oil passage and is discharged through the feedback oil port 13. The design of the throttling hole 61 can limit the flow rate of the hydraulic oil, thereby playing a throttling role; the setting of the blocking member 4 ensures the one-way flow of the hydraulic oil, that is, the hydraulic oil can only flow from the throttling hole 61 to the oil passage, and cannot flow in the opposite direction.

[0047] In this embodiment, the blocking member 4 is a steel ball. As a common mechanical component, the steel ball has the advantages of high hardness, good wear resistance, strong corrosion resistance, and long service life. Using the steel ball as the blocking member 4 in the one-way throttling channel can effectively control the opening and closing of the channel and realize the one-way flow of hydraulic oil.

[0048] Specifically, if Figure 1 As shown, the valve core 2 has a first oil hole 631 axially defined, a second oil hole 632 radially defined, and an annular groove 633 circumferentially defined. The first oil hole 631, the second oil hole 632, and the annular groove 633 are sequentially connected to form an oil passage. The first oil hole 631 communicates with the accommodating hole 62, and the annular groove 633 communicates with the feedback oil port 13 and the oil gap 32, respectively. The interaction of the first axial oil hole 631, the second radial oil hole 632, and the annular groove 633 allows hydraulic oil to flow more smoothly within the oil passage, reducing oil flow resistance and pressure loss.

[0049] In this embodiment, if Figure 1 As shown, the pressure-compensating valve also includes a plug 7, which is disposed within the first end 21 of the valve core 2. The throttle hole 61 and the receiving hole 62 are defined within the plug 7. As an independent component, the plug 7 can be precision-machined separately to ensure the dimensional accuracy of the throttle hole 61 and the receiving hole 62, and to facilitate the placement of the sealing member 4 within the receiving hole 62. If the throttle hole 61 or the receiving hole 62 becomes clogged during use, only the plug 7 needs to be replaced, without having to replace the entire valve core 2. Placing the plug 7 behind the valve core 2 to form a one-way throttling channel reduces processing costs, assembly difficulty, and maintenance costs.

[0050] In an optional embodiment, Figure 1As shown, the valve core 2 is provided with a receiving groove, and the plug 7 is received in the receiving groove and is threadedly connected to the valve core 2. Through the threaded connection, the plug 7 can be tightly fixed in the receiving groove of the valve core 2, and is not easy to loosen or fall off; the threaded connection is also convenient for maintenance and replacement. If the plug 7 or the valve core 2 is worn, or the throttle hole 61 or the receiving hole 62 in the plug 7 is clogged during use, the plug 7 can be easily unscrewed to replace the new plug 7 or valve core 2, thereby improving maintenance efficiency. It should be noted that in other embodiments, the plug 7 can also be set in the valve core 2 by being fixed by a clamp or a locking member, and this embodiment does not limit this.

[0051] In some embodiments, the diameter of the first end 21 of the valve core 2 is smaller than the inner diameter of the valve sleeve 1, forming an oil gap 32 between the outer wall of the first end 21 of the valve core 2 and the inner wall of the valve sleeve 1. The diameter of the second end 22 of the valve core 2 is slightly smaller than the inner diameter of the valve sleeve 1 to allow the valve core 2 to slide and guide with the valve sleeve 1. "Slightly smaller" here means that the difference between the inner diameter of the valve sleeve 1 and the diameter of the second end 22 of the valve core 2 is kept within the tolerance range of 1-2 mm. By making the diameter of the first end 21 of the valve core 2 smaller than the valve sleeve 1, an oil gap 32 is formed between the valve sleeve 1 and the valve core 2, ensuring that hydraulic oil can flow into the chamber 31 or out through the oil gap 32. By making the diameter of the second end 22 of the valve core 2 slightly smaller than the inner diameter of the valve sleeve 1, the valve core 2 can only slide axially when sliding, without shaking, thereby reducing collision or wear between the valve core 2 and the valve sleeve 1 and extending the service life of the pressure compensating valve.

[0052] In other embodiments, see Figure 2 The diameter of the valve core 2 is slightly smaller than the inner diameter of the valve sleeve 1, allowing the valve core 2 to slide and guide with the valve sleeve 1. An oil passage groove is axially defined at the first end 21 of the valve core 2 to form an oil passage gap 32. By making the diameter of the valve core 2 slightly smaller than the inner diameter of the valve sleeve 1, the valve core 2 can only slide axially without shaking, thereby reducing collision or wear with the valve sleeve 1 and extending the service life of the pressure compensating valve. The oil passage groove is circumferentially defined at the first end 21 of the valve core 2 to form an oil passage gap 32 between the valve sleeve 1 and the valve core 2, ensuring that hydraulic oil can flow into the chamber 31 or out through the oil passage gap 32.

[0053] Specifically, if Figure 1As shown, the elastic unit includes an elastic member 51 and a mounting seat 52. One end of the elastic member 51 abuts against the second end 22 of the valve core 2, and the other end is disposed on and abuts against the mounting seat 52. The mounting seat 52 is fixedly disposed within the valve sleeve 1, and is located near the end of the valve sleeve 1 near the oil inlet 11. The elastic member 51 ensures that the valve core 2 can move to the corresponding position when subjected to different pressures, thereby changing the area of ​​the oil return port 12 blocked. The mounting seat 52 provides stable support for the elastic member 51, allowing the elastic member 51 to abut against the valve sleeve 1 through the mounting seat 52.

[0054] In this embodiment, the elastic member 51 is a spring.

[0055] Specifically, a mounting seat hole is formed through the mounting seat 52 so that the hydraulic oil can flow from the oil inlet 11 into the valve sleeve 1, that is, the hydraulic oil flowing in from the oil inlet 11 can flow into the valve sleeve 1 through the mounting seat hole, ensuring that the hydraulic oil can flow from the oil inlet 11 into the valve sleeve 1 without hindrance.

[0056] Specifically, if Figure 1 As shown, the second end 22 of the valve core 2 defines an accommodating chamber 23. An elastic member 51 (spring) extends into the accommodating chamber 23 and abuts against the bottom of the chamber 23. By providing the accommodating chamber 23 within the valve core 2 to house the elastic member 51 (spring), the external dimensions of the entire pressure-compensating valve can be significantly reduced, making the entire structure of the pressure-compensating valve more compact.

[0057] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A pressure compensating valve, characterized in that: include: A valve sleeve (1), wherein the valve sleeve (1) has an oil inlet (11), an oil return port (12) and a feedback oil port (13); A valve core (2) and a valve seat (8), wherein the valve seat (8) is arranged at one end of the valve sleeve (1), and the valve core (2) is slidably arranged in the valve sleeve (1) along the axial direction. The valve core (2) has a first end (21) and a second end (22), a chamber (31) is formed between the end of the first end (21) and the valve seat (8), an oil gap (32) is provided between the peripheral side of the first end (21) and the valve sleeve (1), and the oil gap (32) communicates with the chamber (31) and the feedback oil port (13), and the first end (21) is provided with a one-way throttling channel communicating with the chamber (31) and the feedback oil port (13), and a blocking member (4) is provided in the one-way throttling channel, and the blocking member (4) is used to control the one-way flow of hydraulic oil from the chamber (31) to the feedback oil port (13); An elastic unit is arranged between the valve sleeve (1) and the second end (22).

2. The pressure compensating valve according to claim 1, characterized in that The one-way throttling channel comprises a throttling hole (61), a receiving hole (62) and an oil passage which are connected in sequence. The throttling hole (61) is connected to the chamber (31), and the oil passage is connected to the feedback oil port (13). The blocking member (4) is arranged in the receiving hole (62), and the blocking member (4) is used to disconnect or connect the throttling hole (61) and the receiving hole (62).

3. The pressure compensating valve according to claim 2, characterized in that The valve core (2) is provided with a first oil hole (631) in the axial direction, a second oil hole (632) in the radial direction, and an annular groove (633) in the circumferential direction. The first oil hole (631), the second oil hole (632) and the annular groove (633) are connected in sequence to form the oil passage. The first oil hole (631) is connected to the accommodating hole (62), and the annular groove (633) is connected to the feedback oil port (13) and the oil gap (32).

4. The pressure compensating valve according to claim 3, characterized in that The pressure compensation valve further comprises a plug (7), wherein the plug (7) is arranged in the first end (21) of the valve core (2), and the throttle hole (61) and the accommodating hole (62) are opened in the plug (7).

5. The pressure compensating valve according to claim 4, characterized in that: The plug (7) is detachably connected to the valve core (2).

6. The pressure compensating valve according to claim 5, characterized in that The plug (7) is threadedly connected to the valve core (2).

7. The pressure compensating valve according to claim 1, characterized in that The diameter of the first end (21) of the valve core (2) is smaller than the inner diameter of the valve sleeve (1) to form the oil-passing gap (32), and the second end (22) of the valve core (2) is in sliding guide cooperation with the valve sleeve (1).

8. The pressure compensating valve according to claim 1, wherein: The valve core (2) and the valve sleeve (1) are slidably guided and matched, and the first end (21) of the valve core (2) is provided with an oil passage groove (211) along the axial direction to form the oil passage gap (32).

9. The pressure compensating valve according to claim 1, characterized in that The elastic unit comprises an elastic member (51) and a mounting seat (52); one end of the elastic member (51) abuts against the second end (22) of the valve core (2); the other end is arranged on the mounting seat (52) and abuts against the mounting seat (52); the mounting seat (52) is fixedly arranged in the valve sleeve (1).

10. The pressure compensating valve according to claim 9, characterized in that The second end (22) of the valve core (2) is provided with an accommodating cavity (23), and the elastic member (51) extends into the accommodating cavity (23) and abuts against the bottom of the accommodating cavity (23).

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