Pilot-operated overflow valve

Abstract

The utility model discloses a pilot-operated overflow valve, and belongs to the field of overflow valves. The overflow valve comprises a main valve, the main valve is provided with a first oil cavity and a first oil outlet, a first spring supports a first valve element part to plug an oil inlet, and the oil inlet communicates with the first oil cavity through a damping hole of the first valve element; the pilot valve is axially connected with the main valve, the pilot valve is provided with a second oil cavity and a second oil outlet, the second oil cavity is communicated with the first oil cavity through a connecting port, and a second spring supports a second valve element to block the connecting port; the elastic coefficient of the second spring is larger than that of the first spring. The technical problem that an existing pilot-operated type overflow valve cannot adjust sudden change of fluid pressure during small flow is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of overflow valves, and in particular to a pilot-operated overflow valve. Background Technology

[0002] The overflow valve is also called a safety valve, which includes a pilot overflow valve, a direct-acting overflow valve, etc. As the name implies, its function is to ensure the pressure of the fluid in the pipeline and prevent the occurrence of phenomena such as pipe bursts caused by excessive pressure in the pipeline. The overflow valve is equipped with a spring and a valve core to control the movement of the valve core through the fluid pressure difference, and then control the opening or closing of different passages in the valve body to achieve fluid pressure relief.

[0003] However, the current pilot-operated relief valve cannot regulate sudden changes in fluid pressure at low flow rates. Contents of utility model

[0004] The main purpose of the utility model is to provide a pilot-operated relief valve, which aims to solve the technical problem that the current pilot-operated relief valve cannot adjust the sudden change of fluid pressure at a small flow rate.

[0005] To achieve the above purpose, the utility model proposes a pilot-operated relief valve, comprising: a main valve, the main valve is provided with a first oil chamber and a first oil outlet, a first spring supports a first valve core to partially block an oil inlet, and the oil inlet is connected to the first oil chamber through a damping hole of the first valve core;

[0006] Pilot valve, the pilot valve is axially connected to the main valve, the pilot valve is provided with a second oil chamber and a second oil outlet, the second oil chamber is connected to the first oil chamber through a connecting port, and a second spring supports a second valve core to block the connecting port;

[0007] The elastic coefficient of the second spring is greater than the elastic coefficient of the first spring.

[0008] Optionally, in an embodiment of the utility model, the overflow valve further includes a filter screen, and the filter screen is arranged at the oil inlet.

[0009] Optionally, in an embodiment of the utility model, the overflow valve further includes a clamping ring and a gasket, the clamping ring is arranged on the side of the filter screen away from the damping hole, and the gasket is arranged on the side of the filter screen close to the damping hole.

[0010] Optionally, in an embodiment of the present utility model, the second valve core includes a columnar head, and the columnar head extends into the interior of the first spring through the connecting port.

[0011] Optionally, in an embodiment of the present utility model, the second valve core includes a rod body, and the second spring is sleeved on the outer circumference of the rod body and fits with the rod body.

[0012] Optionally, in an embodiment of the present utility model, both the first oil outlet and the second oil outlet are communicated with the fuel tank.

[0013] Optionally, in an embodiment of the present utility model, the aperture of the second oil outlet is larger than that of the first oil outlet, and / or,

[0014] the number of the second oil outlets is more than that of the first oil outlets.

[0015] Optionally, in an embodiment of the present utility model, the axis line of the first valve core is collinear with that of the second valve core.

[0016] Optionally, in an embodiment of the present utility model, the first valve core is provided with a conical cavity which gradually narrows from the oil inlet towards the direction of the first spring, and the damping hole communicates the conical cavity with the first oil cavity.

[0017] Optionally, in an embodiment of the present utility model, the connection port is frustum-shaped, and the blocking section of the second valve core corresponds to the shape of the connection port.

[0018] Compared with the prior art, the present utility model can at least achieve the following beneficial effects. The overflow valve proposed in this solution has three working states. When the oil fluid enters the first oil cavity of the main valve through the damping hole, the pressure of the oil fluid flowing through the damping hole decreases, resulting in a pressure difference on both sides of the first valve core. When the pressure difference on both sides of the first valve core is small, the first valve core will not move, and the oil fluid overflows from the first oil outlet; when the pressure of the oil fluid increases to a certain extent, the pressure difference on both sides of the first valve core increases, causing the first valve core to move under the action of the pressure difference, and the first valve core no longer blocks the oil inlet, that is, the oil fluid can directly enter the first oil cavity and then flow out from the first oil outlet to complete the overflow; when the oil fluid pressure increases again, the oil fluid in the first oil cavity pushes the second valve core, and the first oil cavity is communicated with the second oil cavity, and part of the oil fluid can enter the second oil cavity at this time and complete the overflow through the second oil outlet. In summary, when the flow rate of the oil fluid is small, the oil fluid can complete the overflow through the path of damping hole - first oil cavity - first oil outlet, and when there is a pressure mutation when the oil fluid flow rate is small, the pressure of the oil fluid can also be adjusted by the movement of the first valve core, solving the technical problem that the current pilot-operated overflow valve cannot adjust the fluid pressure mutation at small flow rates.

[0019] In addition, by setting the elastic coefficient of the second spring to be greater than that of the first spring and the second valve core blocking the connection port under normal conditions, this solution realizes the dynamic adjustment of oil fluids with different pressures. Description of the Drawings

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0021] Figure 1 It is the left view of an embodiment of the pilot-operated relief valve of the present invention;

[0022] Figure 2 For Figure 1 The sectional view taken along A-A in

[0023] Figure 3 It is the three-dimensional view of the pilot-operated relief valve of the present invention.

[0024] Explanation of the reference numerals in the drawings:

[0025] 100, main valve; 110, first oil chamber; 120, first oil outlet; 130, first spring; 140, first spool; 141, conical cavity; 142, damping hole; 200, pilot valve; 210, second oil chamber; 220, second oil outlet; 230, second spring; 240, second spool; 241, columnar head; 242, plugging section; 243, rod body; 300, oil inlet; 400, connection port; 500, filter screen; 600, gasket; 700, snap ring;

[0026] The realization, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. Specific embodiments

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0029] In the present utility model, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0030] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or the solution where A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0031] Referring to Figures 1 to 3 , the present utility model provides a pilot-operated relief valve, and the relief valve includes:

[0032] A main valve 100, a first oil chamber 110 and a first oil outlet 120 are formed on the side wall of the main valve 100. A first spring 130 supports a first spool 140 to partially block an oil inlet 300, and the oil inlet 300 communicates with the first oil chamber 110 through a damping hole 142 of the first spool 140;

[0033] A pilot valve 200, the pilot valve 200 is axially connected to the main valve 100. The pilot valve 200 is provided with a second oil chamber 210 and a second oil outlet 220. The second oil chamber 210 communicates with the first oil chamber 110 through a connection port 400, and a second spring 230 supports a second spool 240 to block the connection port 400;

[0034] The elastic coefficient of the second spring 230 is greater than that of the first spring 130.

[0035] The overflow valve has three working states. When the oil fluid enters the first oil chamber 110 of the main valve 100 through the damping hole 142, the pressure of the oil fluid flowing through the damping hole 142 decreases, resulting in a pressure difference on both sides of the first valve core 140. When the pressure difference on both sides of the first valve core 140 is small, the first valve core 140 will not move, and the oil fluid overflows at the first oil outlet 120. When the pressure of the oil fluid increases to a certain extent, the pressure difference on both sides of the first valve core 140 increases, causing the first valve core 140 to move under the action of the pressure difference. The first valve core 140 no longer blocks the oil inlet 300, that is, the oil fluid can directly enter the first oil chamber 110 and then flow out from the first oil outlet 120 to complete the overflow. When the oil fluid pressure increases again, the oil fluid in the first oil chamber 110 pushes the second valve core 240, and the first oil chamber 110 is connected to the second oil chamber 210. At this time, part of the oil fluid can enter the second oil chamber 210 and complete the overflow through the second oil outlet 220. In summary, when the flow rate of the oil fluid is small, the oil fluid can complete the overflow through the path of the damping hole 142 - the first oil chamber 110 - the first oil outlet 120. When the pressure of the oil fluid changes suddenly when the flow rate is small, the pressure of the oil fluid can also be adjusted by the movement of the first valve core 140, solving the technical problem that the current pilot-operated overflow valve cannot adjust the sudden change of fluid pressure at small flow rates.

[0036] In addition, in this solution, by setting the elastic coefficient of the second spring 230 to be greater than that of the first spring 130 and the second valve core 240 blocking the connection port 400 under normal conditions, the dynamic adjustment of oil fluid with different pressures is realized.

[0037] Since the function of the second valve core 240 is to relieve pressure and overflow the oil fluid when the oil fluid pressure is high, and at this time, rapid pressure relief of the oil fluid is required. Therefore, the aperture of the second oil outlet 220 is set to be larger than that of the first oil outlet 120 and the number of the second oil outlets 220 is more than that of the first oil outlets 120 to achieve rapid pressure relief of the oil fluid when the oil fluid pressure is too high.

[0038] A conical cavity 141 is formed in the first valve core 140. When the first valve core 140 does not move, the conical cavity 141 can guide the oil fluid entering the first oil chamber 110 and lead the oil fluid to enter the first oil chamber 110 through the damping hole 142.

[0039] The second valve core 240 has a columnar head 241, a rod body 243 and a blocking section 242. The columnar head 241 extends into the first spring 130 to provide preventive limitation to the first spring 130. The rod body 243 is used to sleeved with the second spring 230. The structure of the blocking section 242 corresponds to the shape of the connection port 400. The connection port 400 is frustum-shaped, and the blocking section 242 is also a frustum structure. The structures of the connection port 400 and the blocking section 242 both gradually narrow from the direction of the second spring 230 towards the first spring 130.

[0040] In a connection mode, the first oil outlet 120 and the second oil outlet 220 of the overflow valve are both connected to the fuel tank. In this connection mode, the oil pressure in the first oil chamber 110 and the second oil chamber 210 is zero in real time. When the first spool 140 does not move, the pressure difference on both sides of the first spool 140 is the oil pressure. When the second spool 240 does not move, the pressure difference on both sides of the second spool 240 is also the oil pressure. This connection mode enables the first spool 140 and the second spool 240 to respond quickly to changes in oil pressure. The overflow valve can generate structural dynamic changes in a timely manner according to changes in oil pressure to complete pressure relief and overflow.

[0041] Furthermore, the second spool 240 is designed to have a columnar head 241, and the columnar head 241 extends into the first spring 130. The outer periphery of the first spring 130 abuts against the wall of the first oil chamber 110 to provide a certain limit to the spring. In addition, in order to prevent the first spring 130 from shaking in the first oil chamber 110, resulting in the first spring 130 not being normally squeezed by the first spool 140, the columnar head 241 is provided to produce a preventive limiting effect on the first spring 130, that is, to limit the shaking amplitude of the first spring 130. Similarly, the second spring 230 is sleeved on the rod body 243 of the second spool 240 and fits with the rod body 243, which can prevent the second spring 230 from shaking and make it stably arranged in the second oil chamber 210.

[0042] Since the position movement of the first spool 140 and the second spool 240 of the pilot-operated overflow valve is realized through the elastic deformation of the spring, if debris in the oil enters the pilot-operated overflow valve and prevents the first spool 140 or the second spool 240 from resetting, causing the inlet port 300 to be directly connected to the first oil chamber 110 at all times or the first oil chamber 110 to be connected to the second oil chamber 210 at all times, the overflow valve will lose its function of dynamically regulating the oil pressure. For this reason, a filter screen 500 is provided at the inlet port 300 to prevent debris from entering the overflow valve.

[0043] During the working process, as the oil pressure changes, the first spool 140 will be continuously driven by the first spring 130 to move. Therefore, the first spool 140 will inevitably impact the filter screen 500. Since the first spool 140 has a conical cavity 141, the first spool 140 will generate a large pressure on the filter screen 500 when it impacts the filter screen 500. Repeated impacts will cause the filter screen 500 to deform and fail. To extend the service life of the filter screen 500, a gasket 600 is provided between the filter screen 500 and the first spool 140. The first spool 140 first impacts the gasket 600. After the gasket 600 absorbs part of the impact energy, it is then transmitted to the filter screen 500. Moreover, the contact area between the gasket 600 and the filter screen 500 is large, and the pressure generated by the gasket 600 on the filter screen 500 is small, which can effectively weaken the deformation of the filter screen 500.

[0044] The impact of the first spool 140 on the filter screen 500 may also cause the filter screen 500 to fall off. To strengthen the fixation of the filter screen 500, a snap ring 700 is provided to limit the filter screen 500. The snap ring 700 can deform to a certain extent. During installation, the snap ring 700 is squeezed to make it enter the overflow valve, filling the space between the filter screen 500 and the oil inlet 300. After the snap ring 700 is installed, its shape is restored and it firmly fills the space between the filter screen 500 and the oil inlet 300, completing the fixation of the filter screen 500.

[0045] In addition, in this pilot-operated overflow valve, the main valve 100 and the pilot valve 200 are axially connected, that is, the main valve 100 and the pilot valve 200 are of an integrated structure, which is different from the traditional pilot-operated overflow valve. In the traditional pilot-operated overflow valve, the main valve 100 and the pilot valve 200 are of a split structure. The valve body of this structure is complex to cast and the oil flow path is long, which will cause an increase in the oil flow loss along the way, thereby affecting the overall efficiency of the machine. The overflow valve proposed in this solution reduces the oil passage for casting and processing, reduces the oil flow loss along the way, and thus improves the overall efficiency of the machine.

[0046] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the description and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A pilot-operated relief valve, characterized in that: The relief valve comprises: A main valve (100), wherein the main valve (100) is provided with a first oil chamber (110) and a first oil outlet (120), a first spring (130) supports a first valve core (140) to partially block an oil inlet (300), and the oil inlet (300) is connected to the first oil chamber (110) through a damping hole (142) of the first valve core (140); A pilot valve (200), the pilot valve (200) is axially connected to the main valve (100), the pilot valve (200) is provided with a second oil chamber (210) and a second oil outlet (220), the second oil chamber (210) is connected to the first oil chamber (110) through a connecting port (400), and a second spring (230) supports a second valve core (240) to block the connecting port (400); The elastic coefficient of the second spring (230) is greater than the elastic coefficient of the first spring (130).

2. The pilot-operated relief valve according to claim 1, characterized in that: The overflow valve further comprises a filter screen (500), and the filter screen (500) is arranged at the oil inlet (300).

3. The pilot-operated relief valve according to claim 2, characterized in that: The overflow valve further comprises a snap ring (700) and a gasket (600), wherein the snap ring (700) is arranged on a side of the filter screen (500) away from the damping hole (142), and the gasket (600) is arranged on a side of the filter screen (500) close to the damping hole (142).

4. The pilot-operated relief valve according to claim 1, characterized in that: The second valve core (240) comprises a columnar head (241), and the columnar head (241) passes through the connecting port (400) and extends into the interior of the first spring (130).

5. The pilot-operated relief valve according to claim 1, characterized in that: The second valve core (240) comprises a rod body (243), and the second spring (230) is sleeved on the outer circumference of the rod body (243) and fits closely to the rod body (243).

6. The pilot-operated relief valve according to claim 1, characterized in that: The first oil outlet (120) and the second oil outlet (220) are both connected to the oil tank.

7. The pilot-operated relief valve according to claim 1, characterized in that: The aperture of the second oil outlet (220) is larger than the aperture of the first oil outlet (120), and / or, The number of the second oil outlets (220) is greater than the number of the first oil outlets (120).

8. The pilot-operated relief valve according to claim 1, characterized in that: The axis center line of the first valve core (140) and the axis center line of the second valve core (240) are collinear.

9. The pilot-operated relief valve according to claim 1, characterized in that: The first valve core (140) is provided with a tapered cavity (141), the tapered cavity (141) is gradually tightened from the oil inlet (300) toward the first spring (130), and the damping hole (142) connects the tapered cavity (141) and the first oil cavity (110).

10. The pilot-operated relief valve according to claim 1, characterized in that: The connecting port (400) is in the shape of a truncated cone, and the blocking section (242) of the second valve core (240) corresponds to the shape of the connecting port (400).

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