Overflow valve capable of accurately controlling low pressure

Abstract

The utility model discloses an overflow valve capable of accurately controlling low pressure, which relates to the technical field of valves and comprises an oil cylinder, an air cylinder and an air pressure control device, an oil piston is slidably arranged in the oil cylinder, the oil cylinder is divided into a first rod cavity and a first rodless cavity by the oil piston, and an oil inlet is arranged on the inner wall of the first rodless cavity far away from the oil piston. An oil outlet is formed in the peripheral wall of the first rodless cavity; an air piston is slidably arranged in the air cylinder, the air cylinder is divided into a second rod cavity and a second rodless cavity by the air piston, and the air piston and the oil piston are connected through a piston rod; the air pressure control device is connected to the second rod cavity and the second rodless cavity, the air pressure control device is connected with a compressed air source, and the air pressure control device is used for controlling air pressure in the second rod cavity and the second rodless cavity. The hydraulic system can accurately control the pressure of hydraulic oil in the oil cylinder.

Description

TECHNICAL FIELD

[0001] The utility model relates to valve technical field, especially in a kind of overflow valve of precision control low pressure. BACKGROUND

[0002] In prior art, overflow valve is usually used to control the outlet pressure of pump, but for the working condition of flow variation, it is difficult to meet the requirement for opening degree control of electric control proportional ball valve, because when flow suddenly increases or decreases, ball valve opening degree needs to respond quickly to increase or decrease opening degree, to meet the stability of pressure, and ball valve action needs to wait for the transmission time of electrical signal and the time of mechanical component rotation, resulting in large adjustment hysteresis, which leads to unable to accurately control pressure stability. SUMMARY

[0003] The utility model discloses at least one of the technical problems existing in the prior art is solved. To this end, the utility model provides a kind of overflow valve of precision control low pressure, can accurately control the hydraulic oil pressure in oil cylinder.

[0004] According to the utility model first aspect embodiment of a kind of overflow valve of precision control low pressure, it include: oil cylinder, cylinder, air pressure control device, the oil piston is slidably arranged in the oil cylinder, the oil cylinder is separated into first rod cavity and first rodless cavity by the oil piston, the first rodless cavity is opened in the inner wall of the oil piston away from oil inlet, oil outlet is opened in the first rodless cavity wall, the gas piston is slidably arranged in the cylinder, the cylinder is separated into second rod cavity and second rodless cavity by the gas piston, the gas piston and the oil piston are connected by piston rod, the air pressure control device is connected to the second rod cavity and the second rodless cavity, the air pressure control device is connected with compressed air source, and the air pressure control device is used to control the air pressure in the second rod cavity and the second rodless cavity.

[0005] According to the utility model embodiment, a kind of overflow valve of precision control low pressure, at least has the following beneficial effects: when the hydraulic oil pressure of entering oil inlet rises, oil piston moves to the direction close to first rod cavity, so that the area of oil outlet blocked by oil piston becomes smaller, the hydraulic oil flow discharged through oil outlet becomes larger, so that the hydraulic oil pressure in first rodless cavity drops, when the hydraulic oil pressure of entering oil inlet reduces, the pushing force that oil piston receives becomes smaller, oil piston moves to the direction close to first rodless cavity, so that the area of oil outlet blocked by oil piston becomes larger, the hydraulic oil flow discharged through oil outlet becomes smaller, so that the hydraulic oil pressure in first rodless cavity rises. Since the pressure that gas piston receives remains unchanged, when oil piston and gas piston are balanced, the pressure that oil piston receives from hydraulic oil also always equal, i.e. can guarantee that the hydraulic oil pressure in first rodless cavity remains stable.

[0006] According to some embodiments of the present application, the oil cylinder and the air cylinder are connected through a connecting fixed rod.

[0007] According to some embodiments of the present application, the piston rod comprises a first connecting rod and a second connecting rod, the first connecting rod is detachably connected with the second connecting rod, the first connecting rod is connected with the oil piston and partially located in the first rod cavity, and the second connecting rod is connected with the air piston and partially located in the second rod cavity.

[0008] According to some embodiments of the present application, the first rod cavity is provided with a piston end cover on the side away from the first rodless cavity, and the first connecting rod penetrates through the piston end cover.

[0009] According to some embodiments of the present application, the piston end cover is connected with an oil seal, and the oil seal is used for sealing the gap between the piston end cover and the first connecting rod.

[0010] According to some embodiments of the present application, the inner diameter of the oil cylinder is greater than the inner diameter of the air cylinder.

[0011] According to some embodiments of the present application, the air pressure control device comprises an adjusting valve and a reversing valve, the second rod cavity is connected with a compressed air source through the reversing valve, the second rodless cavity is connected with the compressed air source through the adjusting valve, the reversing valve has a first state of inputting compressed air into the second rod cavity and a second state of discharging compressed air in the second rod cavity, and the adjusting valve is used for controlling the pressure in the second rodless cavity.

[0012] According to some embodiments of the present application, the second rodless cavity and the second rod cavity are both connected with a pressure sensor.

[0013] According to some embodiments of the present application, the side wall of the first rod cavity is provided with an exhaust port in communication with the outside.

[0014] According to some embodiments of the present application, the compressed air source is a compressed air storage tank, and the compressed air storage tank only outputs compressed air to the air pressure control device, so as to reduce the pressure fluctuation of compressed air during work.

[0015] Additional aspects and advantages of the present application will be given in part in the following description, will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0016] The present application will be further described below in combination with the drawings and embodiments, in which:

[0017] Figure 1A cross section schematic view of the mounting structure of an embodiment of the utility model.

[0018] Reference signs:

[0019] Oil cylinder 100, first rod cavity 110, exhaust port 111, first rodless cavity 120, oil inlet 121, oil outlet 122;

[0020] Oil piston 200;

[0021] Cylinder 300, second rod cavity 310, second rodless cavity 320;

[0022] Gas piston 400;

[0023] Piston rod 500, first connecting rod 510, second connecting rod 520;

[0024] Air pressure control device 600, regulating valve 610, reversing valve 620;

[0025] Fixed rod 700;

[0026] Piston end cover 800, oil seal 810. DETAILED DESCRIPTION

[0027] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0028] In the description of the utility model, it is understood that the orientation description, such as the orientation or position relationship of the upper, lower and the like, is based on the orientation or position relationship shown in the drawings, only for the convenience of describing the utility model and simplifying the description, and is not indicative or implied that the indicated device or element must have a specific orientation, a specific orientation and operation, therefore, it cannot be understood as limiting the utility model.

[0029] In the description of the utility model, multiple means more than two. If there is a description of the first, the second is only used for distinguishing the technical features for the purpose, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0030] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, installation, connection and the like should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.

[0031] Refer toFigure 1As shown, the utility model discloses a kind of overflow valves of accurate control low pressure, comprising: oil cylinder 100, cylinder 300, air pressure control device 600, oil cylinder 100 is slidably provided with oil piston 200, the inside of oil cylinder 100 is separated into first rod cavity 110 and first rodless cavity 120 by oil piston 200, and the gap between oil cylinder 100 and oil piston 200 is sealed by oil piston 200 ring.The inner wall of first rodless cavity 120 far from oil piston 200 is provided with oil inlet 121, so that oil can smoothly enter first rodless cavity 120, and oil inlet 121 is connected with hydraulic pipeline.When it needs to use overflow valve to control oil pump outlet pressure, oil inlet 121 is connected on the outlet pipeline of oil pump, and oil outlet 122 is provided on the peripheral wall of first rodless cavity 120;Oil outlet 122 is used to discharge hydraulic oil in first rodless cavity 120.According to actual situation, the hydraulic oil discharged in oil outlet 122 can be collected by pipeline and sent into oil tank for recycling.Because oil outlet 122 is arranged on the side wall of first rodless cavity 120, when oil piston 200 moves in oil cylinder 100, oil outlet 122 can be shielded, and by changing the flow area of oil outlet 122 being shielded, the flow of hydraulic oil discharged by oil outlet 122 can be controlled.Gas piston 400 is slidably arranged in cylinder 300, and the inside of cylinder 300 is separated into second rod cavity 310 and second rodless cavity 320 by gas piston 400, and gas piston 400 and oil piston 200 are connected by piston rod 500;Air pressure control device 600 is connected with second rod cavity 310 and second rodless cavity 320, air pressure control device 600 is connected with compressed air source, and air pressure control device 600 is used to control the air pressure in second rod cavity 310 and second rodless cavity 320.The pressure difference between second rod cavity 310 and second rodless cavity 320 drives gas piston 400 to move in cylinder 300, and gas piston 400 drives oil piston 200 to move in oil cylinder 100 by piston rod 500.Hydraulic oil enters first rodless cavity 120 from oil inlet 121 and drives oil piston 200 to move towards first rod cavity 110, when oil piston 200 and gas piston 400 are equal in size and opposite in direction, piston rod 500 remains unchanged, when the hydraulic oil pressure entering oil inlet 121 rises, the driving force of oil piston 200 becomes larger, and the driving force of gas piston 400 remains unchanged, so that oil piston 200 moves towards first rod cavity 110, the area of oil outlet 122 being shielded by oil piston 200 becomes smaller, the flow of hydraulic oil discharged through oil outlet 122 becomes larger, the hydraulic oil pressure in first rodless cavity 120 decreases, until the driving force of oil piston 200 and gas piston 400 is equal in size and opposite in direction, oil piston 200 and piston rod 500 remain unchanged.When the hydraulic oil pressure entering the oil inlet 121 decreases, the pushing force on the oil piston 200 decreases, while the force on the gas piston 400 remains unchanged, so the oil piston 200 moves towards the first rodless chamber 120, making the area of the oil outlet 122 blocked by the oil piston 200 larger, and the hydraulic oil flow through the oil outlet 122 smaller, so that the hydraulic oil pressure in the first rodless chamber 120 increases, until the forces on the oil piston 200 and the gas piston 400 are equal in size and opposite in direction, and the oil piston 200 and the piston rod 500 remain in position. Since the pressure on the gas piston 400 remains unchanged, when the forces on the oil piston 200 and the gas piston 400 are balanced, the pressure on the oil piston 200 from the hydraulic oil also remains constant, i.e. the hydraulic oil pressure in the first rodless chamber 120 remains stable.

[0032] Referring to Figure 1 It can be understood that the oil cylinder 100 and the gas cylinder 300 are connected through the connecting fixed rods 700. The connecting fixed rods 700 are symmetrically arranged, and the two ends of the connecting fixed rods 700 are bolted to the oil cylinder 100 and the gas cylinder 300 respectively. This connection mode not only ensures the overall stability of the device, but also makes the structure more compact and saves installation space.

[0033] Referring to Figure 1 It can be understood that the piston rod 500 includes a first connecting rod 510 and a second connecting rod 520, and the first connecting rod 510 and the second connecting rod 520 are connected by screw threads or buckles. The first connecting rod 510 and the second connecting rod 520 are connected together in a detachable manner, which makes the piston rod 500 easy to replace or repair when needed, greatly improving the maintenance efficiency and service life of the device. The first connecting rod 510 is connected to the oil piston 200 and part of the first connecting rod 510 is located in the first rod chamber 110, and the second connecting rod 520 is connected to the gas piston 400 and part of the second connecting rod 520 is located in the second rod chamber 310.

[0034] Referring to Figure 1 It can be understood that the piston end cover 800 is bolted to the side of the first rod chamber 110 away from the first rodless chamber 120, and the first connecting rod 510 passes through the piston end cover 800. The piston end cover 800 not only prevents the oil piston 200 from coming off the oil cylinder 100, but also ensures the sealing of the inside of the oil cylinder 100, preventing dust and debris from entering the first rod chamber 110. The first connecting rod 510 passes through the piston end cover 800, and the piston end cover 800 guides the first connecting rod 510. This design makes the oil piston 200 more stable during reciprocating motion, thereby improving the performance of the entire overflow valve. At the same time, it also ensures that the sealing of the inside of the oil cylinder 100 is not affected, further enhancing the reliability and service life of the oil cylinder 100.

[0035] Referring to Figure 1 As shown in the figure, it can be understood that the oil seal 810 is connected to the piston end cover 800, and the oil seal 810 is used to seal the gap between the piston end cover 800 and the first connecting rod 510. The oil seal 810 plays a lubricating role, making the first connecting rod 510 move more smoothly, and also ensuring the sealing performance and working reliability of the device.

[0036] Referring to Figure 1 As shown in the figure, it can be understood that the inner diameter of the oil cylinder 100 is greater than the inner diameter of the air cylinder 300. Such a design can make the pressure inside the oil cylinder 100 smaller than the pressure inside the air cylinder 300 in the working state, so as to meet the specific working requirements. In this embodiment, the inner diameter of the oil cylinder 100 is 2 times the inner diameter of the air cylinder 300, and the pressure difference change amount of the gas piston 400 is 4 times the pressure change amount of the first rodless chamber 120. If the adjustment accuracy of the gas pressure control device 600 is ±0.05 MPa, the adjustment accuracy of the hydraulic oil pressure in the first rodless chamber 120 can be controlled to be ±0.013 MPa. By adjusting the pressure difference of the gas piston 400 at both ends of the gas pressure control device 600, the hydraulic oil pressure in the first rodless chamber 120 can be accurately adjusted. Especially when the hydraulic oil pressure in the first rodless chamber 120 is less than 0.2 MPa, accurate control can still be achieved.

[0037] Referring to Figure 1 As shown in the figure, it can be understood that the gas pressure control device 600 includes an adjusting valve 610 and a reversing valve 620, and both the adjusting valve 610 and the reversing valve 620 are driven by electricity. The second rodless chamber 320 is connected to the compressed air source through the adjusting valve 610, and the second rodless chamber 320 is connected to the compressed air source through the adjusting valve 610. The reversing valve 620 has a first state of inputting compressed air into the second rodless chamber 310 and a second state of discharging compressed air from the second rodless chamber 310. In normal working state, the reversing valve 620 is in the first state to provide compressed air to the second rodless chamber 310, and the compressed air in the second rodless chamber 310 provides driving force for the movement of the gas piston 400 to the second rodless chamber 320. When the pressure in the first rodless chamber 120, i.e. the pressure at the outlet of the oil pump, needs to be quickly unloaded, the reversing valve 620 is switched to the second state, so that the second rodless chamber 310 is directly connected to the atmosphere, and the pressure in the second rodless chamber 310 is quickly reduced, so that the gas piston 400 moves towards the second rodless chamber 310, thereby driving the oil piston 200 to quickly close the oil outlet 122. The adjusting valve 610 is used to control the pressure in the second rodless chamber 320, so as to control the pressure in the first rodless chamber 120.

[0038] Referring to Figure 1As shown, it can be understood that in order to further improve the accuracy and reliability of the system, the second rodless cavity 320 and the second rod cavity 310 are both connected with pressure sensors. The pressure sensors can monitor the pressure changes in the second rodless cavity 320 and the second rod cavity 310 in real time, measure the pressure difference in the second rodless cavity 320 and the second rod cavity 310 through the pressure sensors, provide accurate feedback information, realize feedback control of the regulating valve 610, and the feedback control logic of the regulating valve 610 is prior art, so it will not be described in detail. Through feedback control, the pressure difference in the second rodless cavity 320 and the second rod cavity 310 can be stably controlled at the preset value. This real-time monitoring and feedback mechanism enables the entire system to automatically adjust according to the actual working conditions, ensuring efficient and stable operation.

[0039] Referring to Figure 1 As shown, it can be understood that the first rod cavity 110 side wall is provided with an exhaust port 111 communicating with the outside. The design of the exhaust port 111 is to exhaust the gas in the cavity when the oil piston 200 moves, so that the pressure in the first rod cavity 110 is always equal to the atmospheric pressure. The air pressure in the first rod cavity 110 remains unchanged during the movement of the oil piston 200, which not only ensures the stability of the force of the oil piston 200, but also avoids potential risks caused by excessive pressure, improving the safety of the entire device.

[0040] Referring to Figure 1 As shown, it can be understood that the compressed air source is a compressed air storage tank, which only outputs compressed air to the air pressure control device 600. This can reduce the impact of air source pressure fluctuations during operation, improving the stability and reliability of the entire system. The design of the compressed air storage tank not only ensures stable supply of the air source, but also further improves the accuracy of the entire system by reducing pressure fluctuations.

[0041] Working principle: when the hydraulic oil pressure entering the oil inlet 121 increases, the pushing force of the oil piston 200 will become larger, the adjusting valve 610 and the reversing valve 620 control the compressed air pressure in the second rod cavity 310 and the second rodless cavity 320, so that the force of the gas piston 400 remains unchanged, so the oil piston 200 moves to the first rod cavity 110 direction, so that the area of the oil outlet 122 is blocked by the oil piston 200 becomes smaller, through the oil outlet 122 discharge to the hydraulic oil flow becomes larger, so that the hydraulic oil pressure in the first rodless cavity 120 decreases, the pushing force of the oil piston 200 gradually decreases, until when the oil piston 200 and the gas piston 400 force is equal in size and opposite direction, the oil piston 200 and the piston rod 500 remain unchanged. When the hydraulic oil pressure entering the oil inlet 121 decreases, the pushing force of the oil piston 200 will become smaller, while the force of the gas piston 400 remains unchanged, so the oil piston 200 moves to the first rodless cavity 120 direction, so that the area of the oil outlet 122 is blocked by the oil piston 200 becomes larger, through the oil outlet 122 discharge to the hydraulic oil flow becomes smaller, so that the hydraulic oil pressure in the first rodless cavity 120 increases, the pushing force of the oil piston 200 gradually increases, until when the oil piston 200 and the gas piston 400 force is equal in size and opposite direction, the oil piston 200 and the piston rod 500 remain unchanged. Because the pressure of the gas piston 400 remains unchanged, when the oil piston 200 and the gas piston 400 force balance, the pressure of the oil piston 200 from the hydraulic oil is always equal, that is, it can guarantee that the hydraulic oil pressure in the first rodless cavity 120 remains stable.

[0042] The above embodiment of the utility model is described in detail in combination with the drawings, but the utility model is not limited to the above embodiment, within the knowledge range possessed by ordinary skilled in the art, various changes can be made without departing from the purpose of the utility model.

Claims

1. A relief valve capable of precisely controlling low pressure, characterized in that, include: A hydraulic cylinder (100) is provided with a sliding piston (200). The hydraulic cylinder (100) is divided into a first rod chamber (110) and a first rodless chamber (120) by the piston (200). An oil inlet (121) is provided on the inner wall of the first rodless chamber (120) away from the piston (200), and an oil outlet (122) is provided on the peripheral wall of the first rodless chamber (120). A cylinder (300) is provided with a piston (400) slidably disposed inside the cylinder (300). The cylinder (300) is divided into a second rod chamber (310) and a second rodless chamber (320) by the piston (400). The piston (400) and the oil piston (200) are connected by a piston rod (500). A pneumatic control device (600) is connected to the second rod chamber (310) and the second rodless chamber (320). The pneumatic control device (600) is connected to a compressed air source and is used to control the pneumatic pressure in the second rod chamber (310) and the second rodless chamber (320).

2. The relief valve capable of precisely controlling low pressure according to claim 1, characterized in that: The hydraulic cylinder (100) and the pneumatic cylinder (300) are connected by a connecting rod (700).

3. The relief valve capable of precisely controlling low pressure according to claim 1, characterized in that: The piston rod (500) includes a first connecting rod (510) and a second connecting rod (520). The first connecting rod (510) and the second connecting rod (520) are detachably connected. The first connecting rod (510) is connected to the oil piston (200) and is partially located in the first rod chamber (110). The second connecting rod (520) is connected to the gas piston (400) and is partially located in the second rod chamber (310).

4. The relief valve capable of precisely controlling low pressure according to claim 3, characterized in that: A piston end cap (800) is provided on the side of the first rod chamber (110) away from the first rodless chamber (120), and the first connecting rod (510) passes through the piston end cap (800).

5. The relief valve capable of precisely controlling low pressure according to claim 4, characterized in that: The piston end cap (800) is connected to an oil seal (810), which is used to seal the gap between the piston end cap (800) and the first connecting rod (510).

6. The relief valve capable of precisely controlling low pressure according to claim 1, characterized in that: The inner diameter of the hydraulic cylinder (100) is larger than the inner diameter of the pneumatic cylinder (300).

7. The relief valve capable of precisely controlling low pressure according to claim 6, characterized in that: The air pressure control device (600) includes a regulating valve (610) and a reversing valve (620). The second rod chamber (310) is connected to a compressed air source through the reversing valve (620), and the second rodless chamber (320) is connected to a compressed air source through the regulating valve (610). The reversing valve (620) has a first state of inputting compressed air into the second rod chamber (310) and a second state of discharging compressed air from the second rod chamber (310). The regulating valve (610) is used to control the pressure in the second rodless chamber (320).

8. The relief valve capable of precisely controlling low pressure according to claim 7, characterized in that: Both the second rodless chamber (320) and the second rod chamber (310) are connected to pressure sensors.

9. The relief valve capable of precisely controlling low pressure according to claim 1, characterized in that: The first rod cavity (110) has an exhaust port (111) on its side wall that communicates with the outside.

10. The relief valve capable of precisely controlling low pressure according to claim 1, characterized in that: The compressed air source is a compressed air storage tank, which only outputs compressed air to the air pressure control device (600) to reduce the pressure fluctuation of the compressed air during operation.

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