Pressure filter valve

Abstract

The pressure filter valve comprises a valve body, and a pressure stabilizing cavity and an oil drainage cavity are formed in the valve body; the valve body is provided with an oil inlet and an oil outlet which are communicated with the pressure stabilizing cavity, an oil inlet damper is installed at the position, located at the oil inlet, of the valve body, and an oil outlet damper is installed at the position, located at the oil outlet, of the valve body. The valve body is provided with an oil return opening communicated with the oil drainage cavity. When the pressure fluctuation amplitude is small, hydraulic oil enters the pressure stabilizing cavity through the oil inlet damper and then enters a downstream oil way through the oil outlet damper; when hydraulic oil passes through the containing cavity and the damper, pressure fluctuation is effectively restrained; when the pressure fluctuation amplitude is large, hydraulic oil enters the pressure stabilizing cavity through the damper at the oil inlet, and when the pressure of the pressure stabilizing cavity is larger than the pre-pressure of the spring of the valve element, the valve element moves in the compression direction of the spring, so that the volume of the pressure stabilizing cavity is enlarged, and the pressure fluctuation rate and the peak value conducted to the damper at the oil outlet are effectively restrained.

Description

Technical Field

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

[0002] The pressure filter valve is a type of control valve that reduces the drastic pressure fluctuations in the hydraulic system oil circuit. It plays a role in suppressing pressure fluctuations and stabilizing oil pressure in the hydraulic circuit, thereby effectively reducing system vibration and noise, and extending the service life of various hydraulic components. Its principle is to use damping, volume, energy storage and other methods to eliminate the instantaneous pressure spikes caused by load changes in the system, thereby achieving the effect of pressure filtering.

[0003] Traditional hydraulic system pressure filtering often uses a single damper or liquid bridge type, which can achieve good results for hydraulic systems with relatively stable loads and small pressure fluctuations, but has poor results for conditions with sudden load changes, large actuator flexibility, and periodic high-frequency switching of pressure. Hydraulic systems often produce large vibrations, noise, and great fluctuations in pump source pressure, which are detrimental to the stable operation of the hydraulic system and the service life of components. To this end, we propose a pressure filter valve. Summary of the invention

[0004] The object of the present invention is to provide a pressure filter valve to solve the problems in the prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a pressure filter valve, comprising a valve body, wherein a pressure stabilizing chamber and an oil drain chamber are provided in the valve body; the valve body is provided with an oil inlet and an oil outlet connected to the pressure stabilizing chamber, an oil inlet damper is installed at the oil inlet of the valve body, and an oil outlet damper is installed at the oil outlet of the valve body; the valve body is provided with an oil return port connected to the oil drain chamber.

[0006] Preferably, the valve body is located in the oil inlet chamber and is sequentially installed with a valve core, a pressure regulating rod and an end cover, the pressure regulating rod passes through the end cover, and a sealing ring is installed on the outer side of the pressure regulating rod.

[0007] Preferably, a spring is provided between the valve core and the pressure regulating rod, and two ends of the spring respectively abut against the valve core and the pressure regulating rod.

[0008] Preferably, the sliding sealing portion of the valve core is provided with a plurality of pressure equalizing grooves.

[0009] Preferably, a valve core damper is installed in the middle of the valve core.

[0010] Preferably, a pressure regulating rod locking nut is installed on one end of the pressure regulating rod located at the end cover, and a retaining ring is provided on one side of the pressure regulating rod locking nut of the pressure regulating rod.

[0011] Preferably, it further includes a limiting rod, which is arranged inside the pressure adjusting rod. The limiting rod is threadedly connected to the pressure adjusting rod, and a sealing ring is installed on the outer side of the middle part of the limiting rod.

[0012] Preferably, both ends of the limiting rod extend to the outside of the pressure adjusting rod. One end of the limiting rod is provided with an internal hexagonal socket, and the limiting rod is fixed by a limiting rod locking nut.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The pressure filtering valve is connected in series to the oil circuit. When the pressure fluctuation amplitude is small, the hydraulic oil enters the pressure stabilizing cavity through the inlet damper, and then enters the downstream oil circuit through the outlet damper. When the hydraulic oil passes through the above-mentioned cavities and dampers, the pressure fluctuation will be effectively suppressed.

[0015] 2. When the pressure fluctuation amplitude is large, the hydraulic oil enters the pressure stabilizing cavity through the inlet damper. When the pressure in the pressure stabilizing cavity is greater than the pre-pressure of the valve core spring, the valve core moves in the direction of spring compression, thereby expanding the volume of the pressure stabilizing cavity. In this way, the pressure fluctuation rate and peak value transmitted to the outlet damper will be effectively suppressed.

[0016] 3. An optional damper is provided on the valve core. When selected, an effective liquid bridge circuit is formed between the inlet, outlet and pressure stabilizing cavity, which can more effectively stabilize the pressure fluctuation.

[0017] 4. A pressure adjusting rod is provided, and the pressure at which the valve core starts to move can be set.

[0018] 5. A limiting rod is provided to limit the maximum displacement of the valve core, so that the suppression of the pressure fluctuation will not overly affect the response speed of the system.

[0019] 6. A pre-pressure spring is provided to set the starting pressure of the valve core and facilitate the reset of the valve core for repeated operation. Description of the Drawings

[0020] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation to the present invention. In the drawings:

[0021] Figure 1 is the structural schematic diagram of the present invention;

[0022] Figure 2 is the structural schematic diagram of the valve core of the present invention;

[0023] Figure 3 is the structural schematic diagram of the pressure adjusting rod of the present invention.

[0024] In the figure: 1. Limit rod; 2. Limit rod lock nut; 3. Retaining ring; 4. Pressure adjusting rod; 5. Pressure adjusting rod lock nut; 6. End cover; 7. Valve body; 8. Sealing ring; 9. Spring; 10. Spool; 11. Spool damper; 12. Oil outlet damper; 13. Oil inlet damper; 21. Oil inlet; 22. Oil outlet; 23. Oil return port; 31. Pressure stabilizing chamber; 32. Oil drain chamber. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention.

[0026] Please refer to Figures 1 - 3 , in an embodiment of the present invention, a pressure filter valve includes a valve body 7, and a pressure stabilizing chamber 31 and an oil drain chamber 32 are defined in the valve body 7; the valve body 7 is provided with an oil inlet 21 and an oil outlet 22 that communicate with the pressure stabilizing chamber 31, an oil inlet damper 13 is installed at the oil inlet 21 of the valve body 7, and an oil outlet damper 12 is installed at the oil outlet 22 of the valve body 7; the valve body 7 is provided with an oil return port 23 that communicates with the oil drain chamber 32.

[0027] Refer to Figure 1 , there are two stepped cavities, namely a pressure stabilizing chamber 31 and an oil drain chamber 32, in the valve body 7. The pressure stabilizing chamber 31 is an empty cavity, providing a fixed effective volume for the pressure filtering function of the valve. A spool 10 is arranged in the oil drain chamber 32, and a sliding seal is formed between it and the inner wall of the oil drain chamber 32 through clearance fit. At the same time, an oil seal is formed between the oil drain chamber 32 and the piston part of the pressure adjusting rod 4 by means of a sealing ring. Threads are provided at the outermost part of the oil drain chamber 32 for installing the end cover 6.

[0028] Refer to Figure 1, the valve body 7 is connected to the external oil circuit through the oil inlet 21, the oil outlet 22 and the oil return port 23. An oil inlet damper 13 is provided in the oil inlet 21, and a damping hole is opened thereon. An oil outlet damper 12 is provided in the oil outlet 22, and a damping hole is also opened thereon. The sizes of the two damping holes are selected according to the pressure and flow characteristics of the hydraulic system. The oil return port 23 is connected to the oil tank through an external oil circuit, and its function is to drain the oil in the spring cavity back to the oil tank without pressure, ensuring that the spool 10 is only subjected to the force of the spring 9 on the side of the oil drain cavity 32. The valve body 7 is sequentially installed with a spool 10, a pressure adjustment rod 4 and an end cover 6 in the oil drain cavity 32. The pressure adjustment rod 4 penetrates the end cover 6. A pressure adjustment rod locking nut 5 is installed at one end of the pressure adjustment rod 4. A retaining ring 3 is provided on one side of the pressure adjustment rod 4 relative to the pressure adjustment rod locking nut 5. A sealing ring 8 is installed on the outer side of the pressure adjustment rod 4. A spring 9 is provided between the spool 10 and the pressure adjustment rod 4. Both ends of the spring 9 abut against the spool 10 and the pressure adjustment rod 4 respectively. A plurality of pressure equalizing grooves are opened on the sliding sealing part of the spool 10. A spool damper 11 is installed in the middle of the spool 10.

[0029] Refer to Figure 1 and Figure 2 , the spool 10 cooperates with the inner wall of the oil drain cavity 32 of the valve body 1 to form a sliding seal. A plurality of pressure equalizing grooves are opened on the sliding sealing part of the spool 10, which can effectively prevent the spool from jamming. At the same time, a damper 11 is provided as an optional component at the end, and a damping hole is opened thereon.

[0030] Refer to Figure 1 and Figure 3 , the pressure adjustment rod 4 is a component for adjusting the preloading pressure of the spring. One end is in the form of a piston, and a sealing ring 8 is provided thereon to prevent the oil in the oil drain cavity 32 from leaking to the outside. At the same time, there is a boss on the piston as the installation surface for one end of the spring 9. The middle section of the pressure adjustment rod 4 is threaded and cooperates with the end cover 6 to adjust the preloading pressure of the spring 9. The other end of the pressure adjustment rod 4 is provided with a retaining ring 3 to limit the maximum stroke of the pressure adjustment rod 4. The outermost part is hexagonal for convenient adjustment with a wrench. At the same time, a light hole and a thread are opened inside the pressure adjustment rod 4 for the installation and sealing of the limiting rod 1. A locking nut 5 is provided on the outer side of the pressure adjustment rod 4 to fix the position of the pressure adjustment rod 4 and prevent it from moving due to hydraulic shock.

[0031] Refer to Figure 1, The limit rod 1 is arranged inside the pressure regulating rod 4 and is connected to it by threads. At the same time, it is sealed by a sealing ring to prevent the oil in the oil leakage chamber 32 from leaking to the outside of the valve along the thread gap. One end of the limit rod 1 is provided with an internal hexagonal socket for adjusting the maximum distance between the limit rod 1 and the valve core 10. At the same time, after the position of the limit rod is fixed, it is fixed by a locking nut 2 to prevent the limit rod 1 from moving due to hydraulic shock. The limit rod 1 is arranged inside the pressure regulating rod 4, the limit rod 1 is connected to the pressure regulating rod 4 by threads, a sealing ring 8 is installed on the outer side of the middle part of the limit rod 1, both ends of the limit rod 1 extend to the outside of the pressure regulating rod 4, one end of the limit rod 1 is provided with an internal hexagonal socket, and the limit rod 1 is fixed by a limit rod locking nut 2.

[0032] Refer to Figure 1 , The end cover 6 is arranged on the outside of the valve and is fixedly connected to the valve body 7 by threads. The internal threads are used to install the pressure regulating rod 4. The spring 9 is arranged between the valve core 10 and the piston side of the pressure regulating rod 4. It is a compression spring. After installation, it has a certain pre-pressure, and the pre-pressure can be adjusted through the pressure regulating rod 4.

[0033] Valve core, arranged inside the valve body, forms a clearance fit seal with the inner cavity of the valve body. There are multiple equalizing grooves on it, which is more conducive to the smooth movement of the valve core inside the valve body and forms an effective seal. One end of it is affected by hydraulic pressure, and the other end is affected by spring force. When the hydraulic pressure exceeds the spring pre-pressure, the valve core will move in the direction of spring compression until the force balance is reached; Pressure regulating rod, one end of which compresses the spring and forms a movable radial seal with the valve body through a seal. The other end is in the form of a screw rod, which can adjust the pre-compression force of the spring through the screwing thread on the end cover and can be locked and positioned through a locking nut; End cover, fixed to the valve body by threads, and at the same time, internal threads are machined in the middle to cooperate with the pressure regulating rod to form an adjusting mechanism; Limit rod, installed inside the pressure regulating rod, used to mechanically adjust and limit the maximum stroke of the valve core; Pressure stabilizing cavity, arranged between the valve core and the inlet and outlet ports, can receive the oil from the inlet port. At the same time, when the oil pressure reaches the value that enables the valve core to move, it obtains a variable volume to receive the oil, and on the other hand, the oil is discharged through the outlet port; Oil leakage cavity, arranged between the valve core and the piston of the pressure regulating rod, with a valve core spring inside, and at the same time is communicated with the oil return port, so that one side of the valve core spring is not affected by hydraulic pressure and only bears the spring force; Spring, arranged inside the oil leakage cavity, connected to the valve core and the pressure regulating rod, used for the reset of the valve core and the setting of the opening pressure. When installed, it has a certain pre-compression amount, and the variable compression amount can be adjusted through the pressure regulating rod to complete the setting of the valve core opening pressure. After the pressure stabilizing cavity reaches the opening pressure, the pressure in the pressure stabilizing cavity is linearly proportional to the displacement of the valve core, and the size of this ratio is determined by the spring stiffness; Damper, arranged in the inlet and outlet ports and the valve core, with damping holes inside, and the size of the damping port or the blockage can be set according to different operating conditions.

[0034] Through the above technical solution, when the pressure filter valve is working properly, the hydraulic oil flows into the valve body from the oil inlet and enters the pressure stabilizing cavity through the damper. When the pressure in the pressure stabilizing cavity is lower than the pressure set by the spool through the preloading spring, the oil flows out of the valve body through the damper at the oil outlet; when the pressure in the pressure stabilizing cavity is greater than the pressure set by the spool through the preloading spring, the spool moves towards the spring side until a force balance state is reached. During this process, the volume of the pressure stabilizing cavity increases, so the amount of hydraulic oil flowing into the pressure stabilizing cavity from the oil inlet is greater than the flow rate of the oil flowing out of the pressure stabilizing cavity at the oil outlet. After the spool reaches the force balance state and remains relatively stationary, the amount of hydraulic oil flowing through the oil inlet and outlet resumes to be equal. Through the above process, when there is a sudden increase in pressure at the oil inlet, the pressure at the oil outlet will increase gradually, and the rate of increase depends on the stiffness of the preloading spring. Thus, when there is a sudden pressure spike at the oil inlet, that is, when the pressure suddenly increases and then rapidly recovers, under the regulation of this pressure filter valve, the pressure fluctuation at the oil outlet will be effectively suppressed and will not be transmitted to the downstream oil circuit, which is very necessary in the pilot oil circuit of a load sensing system. It can effectively reduce the fluctuation of the hydraulic pump source, thereby effectively reducing the abnormal vibration and noise of the hydraulic system and prolonging the service life of hydraulic components.

[0035] The damping holes in the dampers at the oil inlet and outlet need to be determined according to the specific conditions of the pilot oil circuit (considering factors such as flow rate range, pressure range, etc.) and are detachable and replaceable components. This damper group is for initially buffering the oil circuit pressure. That is, when the hydraulic oil pressure fluctuation is not very severe, relying on the combined action of the dampers at the oil inlet and outlet and the pressure stabilizing cavity, the stable buffering of the pilot oil circuit pressure can be achieved.

[0036] The spool damper is an optional component. When spool damping is not required, a component without holes can be selected, which is equivalent to blocking this oil circuit; when spool damping is required, a damper with a damping hole of appropriate size can be selected and installed here. The advantage of using the spool damper is that part of the hydraulic oil in the pressure stabilizing cavity can flow into the drain cavity through this damping hole and then directly flow back to the fuel tank through the oil return port. In this way, together with the dampers at the oil inlet and outlet, it forms a liquid bridge, which is more conducive to the pressure at the oil outlet reaching a stable state quickly.

[0037] The working principle of the present invention is as follows: When the pressure filter valve is working, hydraulic oil enters the valve through the oil inlet 21, and after passing through the oil inlet damper 13, it flows into the pressure stabilizing chamber 31. When the oil circuit pressure is not high, the pressure in the pressure stabilizing chamber is not sufficient to push the valve core 10, and the oil flows through the damper 12 at the oil outlet 22 into the downstream oil circuit. After the hydraulic oil passes through two damping holes and a cavity, the pressure fluctuation will be effectively suppressed, and the pressure of the oil flowing out of the oil outlet 22 is more stable than the pressure at the oil inlet 21. When the oil circuit pressure is high, the pressure in the pressure stabilizing chamber exceeds the pre-pressure of the spring 9 on the other side of the valve core 10, and the valve core 10 is pushed towards the spring side, so that the volume of the pressure stabilizing chamber increases. In this way, a part of the oil flowing into the pressure stabilizing chamber 31 replenishes the cavity, and the other part flows through the damper 12 at the oil outlet 22 into the downstream oil circuit. The pressure of the oil after the above process will also be effectively suppressed. In addition, a damping device 11 that can be optionally installed is provided inside the valve core 10, and damping holes can be opened inside. When the oil circuit requires a more stable transition pressure, this damping device can be used. In this way, a part of the oil in the pressure stabilizing chamber will flow through this damping hole into the oil drain chamber 32. In this way, a liquid bridge is formed by the oil inlet damper 13, the oil outlet damper 12 and the valve core damper 11, and a stable liquid flow can be formed in the oil circuit. In this way, the peak value of the pressure fluctuation of the oil flowing out of the oil outlet 22 will be greatly reduced, and the pressure change will be more stable. For the above-mentioned pre-pressure of the valve core, it can be adjusted according to the system requirements through the pressure adjusting rod 4, and fixed and locked by the lock nut 5 after the adjustment is completed. For the moving stroke of the valve core in the valve body, it can be set through the limit rod 1, and fixed and locked by the lock nut 2 after the adjustment is completed. Limiting the maximum stroke of the valve core is mainly to control the maximum volume of the pressure stabilizing chamber, so that the response speed of the oil circuit pressure conduction can be effectively adjusted.

[0038] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pressure filter valve, comprising a valve body (7), characterized in that: A pressure stabilizing chamber (31) and an oil drain chamber (32) are formed in the valve body (7); an oil inlet (21) and an oil outlet (22) communicating with the pressure stabilizing chamber (31) are formed in the valve body (7), an oil inlet damper (13) is installed at the oil inlet (21) of the valve body (7), and an oil outlet damper (12) is installed at the oil outlet (22) of the valve body (7); a return oil port (23) communicating with the oil drain chamber (32) is formed in the valve body (7).

2. The pressure filtering valve according to claim 1, wherein: A valve core (10), a pressure adjusting rod (4) and an end cover (6) are sequentially installed in the oil drain chamber (32) of the valve body (7), the pressure adjusting rod (4) penetrates through the end cover (6), and a sealing ring (8) is installed on the outer side of the pressure adjusting rod (4).

3. A pressure filter valve according to claim 2, characterized in that: A spring (9) is arranged between the valve core (10) and the pressure adjusting rod (4), and two ends of the spring (9) respectively abut against the valve core (10) and the pressure adjusting rod (4).

4. A pressure filtering valve according to claim 2, wherein: A plurality of pressure equalizing grooves are formed in the sliding sealing part of the valve core (10).

5. The pressure filter valve according to claim 2, wherein: A valve core damper (11) is installed in the middle of the valve core (10).

6. The pressure filtering valve according to claim 2, characterized in that: A pressure adjusting rod locking nut (5) is installed at one end of the pressure adjusting rod (4) located at the end cover (6), and a retaining ring (3) is arranged on one side of the pressure adjusting rod (4) located at the pressure adjusting rod locking nut (5).

7. A pressure filter valve according to claim 2, characterized in that: The device further includes a limiting rod (1), the limiting rod (1) is arranged in the pressure adjusting rod (4), the limiting rod (1) is in threaded connection with the pressure adjusting rod (4), and a sealing ring (8) is installed on the outer side of the middle of the limiting rod (1).

8. A pressure filter valve according to claim 7, characterized in that: Both ends of the limiting rod (1) extend to the outside of the pressure adjusting rod (4), an internal hexagon is arranged at one end of the limiting rod (1), and the limiting rod (1) is fixed by a limiting rod locking nut (2).

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