Novel pressure reducing valve with two-stage pressure regulating precision

Abstract

The invention relates to the technical field of pressure reducing valves, and discloses a novel pressure reducing valve with two-stage pressure regulating precision, which comprises a pressure regulating valve assembly, a first-stage cylinder assembly and a second-stage cylinder assembly are sequentially arranged on the right side of the pressure regulating valve assembly, the pressure reducing valve assembly comprises a valve body and a valve core, and an oil supply port P, a pressure outlet A and an oil drainage port T are respectively formed in the side wall of the valve body. A pressure sensor is arranged at the pressure outlet A; the first-stage air cylinder assembly comprises a first-stage cylinder body and a first-stage piston, the second-stage air cylinder assembly comprises a second-stage cylinder body and a second-stage piston, the valve element, the first-stage piston and the second-stage piston are sequentially connected and coaxially arranged, and air sources are introduced into the left side and the right side of the first-stage piston and the left side and the right side of the second-stage piston respectively to control the valve element to move leftwards and rightwards. The oil supply port P, the pressure outlet A and the oil drainage port T are switched to be connected and disconnected, and the stress balance state of the left side and the right side of the valve element is achieved. According to the invention, the pressure can be adjusted from 0ba, the maximum pressure adjustment range is applied to 20bar, and accurate pressure adjustment can be realized in a small pressure range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure reducing valves, and more particularly to a novel pressure reducing valve with two-stage pressure regulating precision. BACKGROUND

[0002] In a hydraulic system, pressure control is a key link to ensure stable operation of the system, and usually requires a proportional pressure reducing valve to reduce the high-pressure oil source provided by the system to the stable pressure required by the terminal to adapt to the differentiated needs of different workstations or actuators. Currently, proportional pressure reducing valves on the market are mainly divided into two structures: pilot type and direct acting type.

[0003] The pilot type proportional pressure reducing valve is composed of a main valve and a pilot valve, and the pressure of the pilot valve is adjusted by the driving armature of an electromagnet, and the main valve core is actuated by the pilot valve to achieve pressure reduction. Although it has a wide pressure regulating range, it can be closed to 0, but it has a large pressure loss when passing through the rated flow, and a large pressure difference is required to meet the terminal flow demand. In addition, since the pre-tightening force of the pilot valve spring needs to be overcome, linear adjustment can only be performed after the pressure exceeds the pre-tightening force, so there is a starting pressure regulating point, and the pressure below this point is in a range that cannot be adjusted, resulting in that the low pressure section cannot be precisely controlled.

[0004] The direct acting type proportional pressure reducing valve directly pushes the moving armature and valve core by the electromagnet to achieve pressure reduction, but its pressure regulating range is small. If you want to expand the pressure regulating range, you need to increase the electromagnetic force or the stiffness of the spring. The pre-compression force of the spring will result in that the low pressure section (less than the starting pressure point) cannot be precisely adjusted, and the precision requirement of the low pressure working condition cannot be met.

[0005] In addition, the existing proportional pressure reducing valve generally has the problem of "conflict between regulating range and low pressure precision": the larger the regulating range, the worse the regulating precision of the low pressure section. Similar to the relationship between the range and precision of a sensor (for example, when measuring 0.5MPa, the measurement result of a 1MPa range sensor is more accurate). This makes it difficult for existing technology to meet the needs in scenarios that require both large-scale pressure regulation and high precision in low pressure sections (such as hydraulic actuator testing, multi-station differential pressure control, etc.). SUMMARY

[0006] Therefore, the present application provides a novel pressure reducing valve with two-stage pressure regulating precision, which can regulate the pressure from 0ba to a maximum pressure regulating range of 20bar, and also achieve precise pressure regulation in a small pressure range.

[0007] In order to achieve the above object, the novel two-stage pressure regulating precision pressure reducing valve provided by the application comprises a pressure regulating valve assembly, a first-stage cylinder assembly and a second-stage cylinder assembly are sequentially arranged on the right side of the pressure regulating valve assembly, the pressure reducing valve assembly comprises a valve body and a valve core which is slidably connected in the valve body, a plurality of protruding stop portions are arranged on the side wall of the valve core, the stop portions extend to the side wall of the inner cavity of the valve body, a left end cover and a right end cover are respectively arranged on the left side and the right side of the valve body, an oil supply port P, a pressure outlet A and a drain port T which are in communication with the inner cavity of the valve body are respectively arranged on the side wall of the valve body, and a pressure sensor is arranged at the pressure outlet A.

[0008] The first-stage cylinder assembly comprises a first-stage cylinder body and a first-stage piston arranged in the first-stage cylinder body, the second-stage cylinder assembly comprises a second-stage cylinder body and a second-stage piston arranged in the second-stage cylinder body, the valve core, the first-stage piston and the second-stage piston are sequentially connected and coaxially arranged, and the first-stage cylinder body and the second-stage cylinder body are fixedly connected with the right end cover.

[0009] By respectively introducing the gas source into the left side and the right side of the first-stage piston and the second-stage piston to control the left-right movement of the valve core and switching the on-off of the oil supply port P, the pressure outlet A and the drain port T, the force balance state of the left side and the right side of the valve core is realized.

[0010] Preferably, when the pressure of the pressure outlet A is 0, the pressure reducing valve is in a closed state, the gas source is introduced into the left side of the first-stage piston and the second-stage piston, the first-stage piston and the second-stage piston drive the valve core to move to the right side, at this time, the oil supply port P is blocked and closed by the stop portion on the valve core, the pressure outlet A is in communication with the drain port T, and the oil in the oil supply port P cannot enter the pressure outlet A to generate a force on the valve core, at this time, the pressure of the pressure outlet A is 0.

[0011] Preferably, when the gas source is introduced into the right side of the first-stage piston, the pressure reducing valve is in a small pressure regulating state, the first-stage piston drives the valve core to move to the left side, at this time, the drain port T is blocked and closed by the stop portion on the valve core, the oil supply port P is in communication with the pressure outlet A, and at the same time, the oil in the pressure outlet A acts on the left side of the valve core to generate a rightward force F0, the right side of the valve core is subjected to the leftward thrust F1 of the first-stage piston, when F0 and F1 are unbalanced, the valve core is pushed to move to the right, when the pressure outlet A is in communication with the drain port T, the pressure outlet A will drain oil to the drain port T, then the pressure of the pressure outlet A decreases, the valve core moves to the left again, and such reciprocating movement continues until the two ends of the valve core are in a force balance state.

[0012] Preferably, when the right side of the primary piston and the secondary piston is connected to the air source, the pressure reducing valve is in the large pressure adjustment state, the primary piston pushes the valve core to the left, the oil outlet T is blocked by the stop on the valve core, the oil inlet P is connected to the pressure outlet A, the oil pressure of the pressure outlet A increases, the oil pressure of the pressure outlet A acts on the left side of the valve core to generate a right force F0, the right side of the valve core is subjected to the thrust F1 of the primary piston and the thrust F2 of the secondary piston, when F0 and F1+F2 are unbalanced, the valve core is pushed to move right, the pressure outlet A leaks to the oil outlet T, then the pressure of the pressure outlet A decreases, the valve core moves left again, and so on until the two ends of the valve core are in a force balance state.

[0013] Preferably, F0 is equal to the pressure of the pressure outlet A multiplied by the force area of the valve core.

[0014] Preferably, the left side of the primary piston and the secondary piston is connected to one gas outlet of the two-position five-way directional valve in parallel, the right side of the primary piston and the secondary piston is connected to the other gas outlet of the two-position five-way directional valve in parallel, and the gas inlet of the two-position five-way directional valve is connected to a compressed air source.

[0015] Preferably, a gas proportional pressure reducing valve is arranged on the main pipeline of the primary piston and the secondary piston in parallel, and an electromagnetic on-off valve is arranged on the branch pipeline of the secondary piston.

[0016] Preferably, the two-position five-way directional valve, the gas proportional pressure reducing valve and the electromagnetic on-off valve are connected to a controller.

[0017] Preferably, the opening position of the stop on the valve core is provided with a circular arc notch, so that there is a transition opening when the valve core is opened and closed, avoiding impact when the valve core is opened or closed at the valve port position, and realizing stable output pressure.

[0018] Preferably, a plug and connecting block assembly is arranged below the valve body, and the oil inlet P and the pressure outlet A penetrate through the plug and connecting block assembly.

[0019] According to the above technical solution, compared with the prior art, the novel two-stage pressure regulating precision pressure reducing valve provided by the present application has the following beneficial effects:

[0020] 1. According to the present application, the valve core and the two-stage piston are coaxially connected and form a force balance mechanism through the cooperative design of the pressure regulating valve assembly and the primary and secondary cylinder assemblies, not only can the pressure be adjusted from 0 bar, but also can cover the maximum range of 20 bar, solving the problem that the traditional pressure reducing valve cannot be adjusted or has insufficient precision in the low pressure section, and at the same time, the valve core can be automatically adjusted through dynamic balance when the flow or load changes, ensuring stable pressure output.

[0021] 2、The present application only drives the valve core on the right side of the first-stage piston through the ventilation in the low-pressure adjustment state, and realizes the adjustment by using the dynamic balance between the oil pressure on the left side of the valve core and the thrust of the first-stage piston, and the thrust controllable range is smaller due to the participation of the single-stage piston, which effectively improves the adjustment accuracy of the low-pressure section; the two-stage pistons are ventilated at the same time in the high-pressure adjustment state, the thrust is superimposed to expand the stress range, which ensures the adjustment capacity of the high-pressure section, and the two form a segmented precise adjustment mechanism, which takes into account the wide range and high precision;

[0022] 3、The present application realizes the automation and intelligentization of pressure adjustment through the connection design of the first-stage and second-stage pistons, two-position five-way directional valve, gas proportional pressure reducing valve, electromagnetic on-off valve and controller, the working state of the first-stage / two-stage piston can be quickly switched through the on-off of the electromagnetic on-off valve, and the pressure adjustment of the gas proportional pressure reducing valve, so that the device can flexibly adapt to the pressure demand under different working conditions and reduce manual intervention;

[0023] 4、The present application forms a transition opening in the valve core opening and closing process through the arc-shaped notch structure of the valve core stop, avoids the pressure impact caused by the sudden opening and closing of the valve port, reduces the pressure fluctuation, makes the output pressure more stable, especially improves the accuracy when adjusting in the low-pressure section, and the calculation method of F0 provides a theoretical basis for quantitative control of pressure adjustment, which is convenient for presetting the target pressure through the gas circuit parameters, and improves the controllability and consistency of the adjustment. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating labor under the premise of providing the drawings.

[0025] Figure 1 It is a schematic diagram of the new two-stage pressure regulating precision pressure reducing valve connected with the gas circuit control part of the present application;

[0026] Figure 2 It is a schematic diagram of the overall structure of the new two-stage pressure regulating precision pressure reducing valve of the present application;

[0027] Figure 3 It is an enlarged view of the valve core of the present application;

[0028] Figure 4 It is a force balance relationship diagram of the valve core of the present application;

[0029] Figure 5 It is a pressure regulation cycle test curve diagram of the present application.

[0030] Explanation of reference signs: 1 - pressure reducing valve assembly, 2 - compressed air source, 3 - two-position five-way directional control valve, 4 - gas proportional pressure reducing valve, 5 - electromagnetic on-off valve, 6 - pressure sensor, 7 - primary cylinder assembly, 8 - secondary cylinder assembly; 9 - circular arc type notch

[0031] 1.1 - left end cover, 1.2 - valve body, 1.3 - first plug, 1.4 - adjustable flow port, 1.5 - valve core, 1.6 - second plug, 1.7 - oil drain port T, 1.8 - right end cover, 1.9 - first sealing ring, 1.10 - plug and connecting block assembly, 1.11 - oil supply port P, 1.12 - second sealing ring, 1.13 - pressure outlet A, 1.14 - pressure sensor, 1.15 - third sealing ring, 1.16 - mounting block, 1.17 - connecting bolt, 2.1 - primary cylinder body, 2.2 - primary piston, 3.1 - cylinder connecting rod, 3.2 - secondary piston, 3.3 - secondary cylinder body. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] Please refer to the drawings Figures 1-5 The novel two-stage pressure regulating precision pressure reducing valve disclosed in the present application comprises a pressure regulating valve assembly 1, a primary cylinder assembly 7, a secondary cylinder assembly 8, a gas circuit control part, an electrical control part and five parts, adopts force transmission control, and is accurately adjusted through the principle of mechanical balance.

[0034] As Figure 1 , Figure 2 shown, the pressure regulating valve assembly 1 comprises a valve body 1.2, a valve core 1.5, a left end cover 1.1, a right end cover 1.8 and a sealing ring.

[0035] The valve core 1.5 is slidingly connected to the inside of the valve body 1.2 and connected with the cylinder (the primary cylinder assembly 7 and the secondary cylinder assembly 8) in a floating connection form, so that the valve core 1.5 is coaxial with the valve hole of the pressure reducing valve, avoiding different axes among the valve core 1.5, the valve hole and the cylinder piston due to the installation size error of the cylinder. Several equalizing grooves are arranged on the valve core 1.5, and the medium can enter and fill the equalizing grooves, thereby reducing the resistance when the valve core 1.5 moves, and better allowing the valve core 1.5 to be coaxial with the valve hole.

[0036] The side wall of the valve body 1.2 is provided with an oil supply port P1.11, a pressure outlet A1.13 and a drain port T1.7, which are in communication with the inner cavity of the valve body 1.2, and the pressure outlet A1.13 is provided with a pressure sensor 1.14. The side wall of the valve core 1.5 is provided with a plurality of protruding stop portions, which extend to the side wall of the inner cavity of the valve body 1.2.

[0037] The side wall of the valve body 1.2 is provided with a plurality of adjustable flow ports 1.4, and the first plug 1.3 and the second plug 1.6 are arranged in the adjustable flow ports 1.4, respectively. The left end cover 1.1 and the right end cover 1.8 are arranged on the left and right sides of the valve body 1.2, respectively, and the first sealing ring 1.9 and the third sealing ring 1.15 are arranged on the left and right sides of the valve body 1.2, respectively, to ensure the sealing effect. The lower portion of the valve body 1.2 is provided with a plug and connecting block assembly 1.10, the oil supply port P1.11 and the pressure outlet A1.13 penetrate the plug and connecting block assembly 1.10, and the second sealing ring 1.12 is arranged between the valve body 1.2 and the plug and connecting block assembly 1.10.

[0038] The primary cylinder assembly 7 and the secondary cylinder assembly 8 are connected to the right side of the pressure regulating valve assembly 1 in sequence. The primary cylinder assembly 7 includes a primary cylinder body 2.1 and a primary piston 2.2 arranged inside the primary cylinder body 2.1. The secondary cylinder assembly 8 includes a secondary cylinder body 3.3 and a secondary piston 3.2 arranged inside the secondary cylinder body 3.3. The valve core 1.5, the primary piston 2.2 and the secondary piston 3.2 are connected in sequence and arranged coaxially. The primary cylinder body 2.1 and the secondary cylinder body 3.3 are fixedly connected with the right end cover 1.8, and the secondary cylinder body 3.3 is fixedly connected with the right end cover 1.8 through the cylinder connecting piece 3.1.

[0039] The valve core 1.5 is connected with the primary piston 2.2 through the connecting bolt 1.17, and the mounting block 1.16 for bearing the connecting bolt 1.17 is arranged on the right side of the valve body 1.2 to guide the movement of the valve core 1.5, the primary piston 2.2 and the secondary piston 3.2.

[0040] The gas path control part includes a compressed air source 2, a two-position five-way directional control valve 3, a gas proportional pressure reducing valve 4 and an electromagnetic on-off valve 5. The electrical control part is a controller (PLC), and the control type can be 4-20 mA or 0-10 mA. The electrical control part is connected to and controls the gas path control part.

[0041] The left sides of the primary piston 2.2 and the secondary piston 3.2 are connected in parallel and then connected to one gas outlet hole of the two-position five-way directional control valve 3. The right sides of the primary piston 2.2 and the secondary piston 3.2 are connected in parallel and then connected to another gas outlet hole of the two-position five-way directional control valve 3. The compressed air source 2 is connected to the gas inlet hole of the two-position five-way directional control valve 3. The gas proportional pressure reducing valve 4 is arranged on the main pipeline after the primary piston 2.2 and the secondary piston 3.2 are connected in parallel. The electromagnetic on-off valve 5 is arranged on the branch pipeline of the secondary piston 3.2.

[0042] The working principle of the present application is:

[0043] The first and second stage cylinders are used as the actuator, and the gas proportional pressure reducing valve 4 is used to adjust the pressure of 0-5 bar (or about 6 bar) to push the piston of the cylinder, and the piston of the cylinder is mechanically connected with the spool 1.5 of the pressure reducing valve assembly 1.

[0044] The force F0 acting on the spool 1.5 is the product of the pressure of the pressure reducing valve outlet A1.13 and the area of the spool 1.5, and the force F1 (or F1+F2) of the cylinder piston is the product of the input pressure of the gas proportional pressure reducing valve 4 and the effective pressure receiving area of the first stage piston 2.2 (or the first stage piston 2.2+the second stage piston 3.2), and the balance between F1 and F0 is achieved.

[0045] When F0 is greater than F1, the spool 1.5 is pushed to move in the direction of opening the oil drain port T1.7, the opening degree of the oil supply port P1.11 is closed, and the opening degree of the oil drain port T1.7 is opened larger, so that the pressure is reduced, and F0 is reduced accordingly.

[0046] When F0 is less than F1, the spool 1.5 is pushed to move in the direction of opening, the opening degree of the oil drain port T1.7 is closed, and the opening degree of the oil supply port P1.11 is opened larger, so that the pressure is increased, and F0 is increased accordingly.

[0047] The force acting on the spool 1.5 is always balanced with the force of the cylinder piston, and as long as the spool 1.5 is unbalanced on both sides, the spool 1.5 will be pushed to move, the opening degree of the oil supply port P1.11 will be larger, and the opening degree of the oil drain port T1.7 will be closed or the opening degree of the oil supply port P1.11 will be closed and the opening degree of the oil drain port T1.7 will be larger, so as to realize automatic dynamic balance, so when the flow demand changes or the load changes, as long as the force at the cylinder piston remains unchanged, the outlet pressure of the pressure reducing valve will be adjusted adaptively to maintain stable pressure.

[0048] Working condition one, the pressure of the outlet A1.13 is 0, the pressure reducing valve is in the closed state, the two-position five-way directional valve 3 is not powered, and the gas source is respectively introduced into the left side of the first stage piston 2.2 and the second stage piston 3.2, the first stage piston 2.2 and the second stage piston 3.2 push the spool 1.5 to move to the right until the limit, at this time the oil supply port P1.11 is blocked and closed by the stop portion on the spool 1.5, the outlet A1.13 is connected with the oil drain port T1.7, and the oil cannot enter the outlet A1.13 from the oil supply port P1.11 to generate force on the spool 1.5, although the P port pressure is large, the outlet A1.13 will maintain the pressure of 0.

[0049] Condition two, small pressure regulation: two five-way directional valve 3 is powered, pressure source from compressed air source 2 to the gas proportional pressure reducing valve 4 and the first cylinder assembly 7, electromagnetic switch valve 5 is not powered to be in the closed state, the gas proportional pressure reducing valve out of the gas pressure only into the right side of the first piston 2.2, the first piston 2.2 is forced to push the valve core 1.5 to the left movement, at this time the oil drain port T1.7 is blocked by the stop portion on the valve core 1.5, the oil supply port P1.11 is connected with the pressure outlet A1.13, and the oil in the pressure outlet A1.13 is discharged through the pressure reducing valve and acts on the left side of the valve core 1.5, so that a right force F0 is generated, F0 is equal to the pressure of the pressure outlet A1.13 multiplied by the force area of the valve core 1.5, the right side of the valve core 1.5 is subjected to the left thrust F1 of the first piston 2.2, since F0 and F1 need to be balanced, when F0 and F1 are unbalanced, the valve core 1.5 will be pushed to move right, when the pressure outlet A1.13 is connected with the oil drain port T1.7, the pressure outlet A1.13 will discharge oil to the oil drain port T1.7, and then the pressure of the pressure outlet A1.13 decreases, the valve core 1.5 moves left again, and the valve core 1.5 moves left again. The back and forth movement is until the two ends of the valve core 1.5 are in a force balance state.

[0050] Condition three, large pressure regulation: two five-way directional valve 3 is powered, pressure source flows to the gas proportional pressure reducing valve 4, the first cylinder assembly 7 and the second cylinder assembly 8, and the electromagnetic switch valve 5 is powered to be in the open state, the gas proportional pressure reducing valve 4 out of the gas pressure flows to the right side of the first piston 2.2 and the second piston 3.2, the first piston 2.2 is forced to push the valve core 1.5 to the left movement, the oil drain port T1.7 is blocked by the stop portion on the valve core 1.5, and the oil supply port P1.11 is connected with the pressure outlet A1.13, the oil pressure of the pressure outlet A1.13 increases, the oil pressure of the pressure outlet A1.13 acts on the left side of the valve core 1.5, so that a force F0 is generated, and the right side of the valve core 1.5 is subjected to the thrust F1 of the first piston 2.2 and the thrust F2 of the second piston. Since F0 and F1+F2 need to be balanced, when F0 and F1+F2 are unbalanced, the valve core 1.5 will be pushed to move right, the pressure outlet A1.13 will discharge oil to the oil drain port T1.7, and then the pressure of the pressure outlet A1.13 decreases, the valve core 1.5 moves left again, and the valve core 1.5 moves left again. The back and forth movement is until the two ends of the valve core 1.5 are in a force balance state.

[0051] As shown in Figure 3 In order to further optimize the above technical scheme, the opening position of the valve core 1.5 is provided with a circular arc type notch 9, which is used to reduce the pressure fluctuation and realize stable output pressure when the valve core 1.5 is opened and closed.

[0052] The pressure reducing valve provided by the application has a two-stage pressure regulating mode, is divided into two regulating ranges, can realize higher accuracy for small pressure range, and can also ensure large-range pressure regulating accuracy, wherein in order to realize more accurate regulating effect, the gas proportional pressure reducing valve 4 with an accuracy of ±0.5% is adopted, the gas proportional pressure reducing valve 4 has high sensitivity, good linearity, and meets the requirements of pilot control, and the accuracy parameters of the gas proportional pressure reducing valve 4 are shown in Table 1.

[0053] Table 1: Parameters of the gas proportional pressure reducing valve

[0054] Linearity Within ± 1% F.S. Hysteresis Within 0.5% F.S. Repeatability Within ± 0.5% F.S. Sensitivity Within 0.2% F.S. Temperature characteristics Within ± 0.12% F.S. / °C

[0055] As shown in Figure 4 the force balance principle of the valve core 1.5, wherein S0 is the force area of the valve core 1.5, P0 is the outlet pressure of the pressure reducing valve, F0 is the force acting on the valve core 1.5 by the outlet pressure, S1 is the effective area of the primary cylinder, P1 is the pressure output by the gas proportional pressure reducing valve 4, F1 is the force acting on the piston of the primary cylinder by the primary cylinder, S2 is the effective area of the secondary cylinder, and F2 is the force acting on the piston of the secondary cylinder by the secondary cylinder.

[0056] Through analysis of the force balance relationship of the structure in the figure, the force balance relationship of the valve core 1.5 is that the force at the left end is balanced with the force at the right end, and if the forces are unbalanced, the valve core 1.5 will move until the forces are balanced, and the force relationship is F0=F1+F2.

[0057] When the small pressure regulating range is used, only the primary cylinder assembly 7 can be used to act and push the primary piston 2.2 by selecting the gas circuit, the balance relationship is P0*S0=P1*S1, the relationship between the outlet pressure P0 of the outlet port A1.13 and the regulating pressure P1 of the gas proportional pressure reducing valve 4 is P0=P1(S1 / S0), which belongs to a linear function and a proportional relationship, the proportional coefficient is directly related to the size of the valve core 1.5 and the cylinder diameter of the primary cylinder assembly 7, and the relationship of the proportional coefficient is calculated during design.

[0058] When the large pressure regulating range is used, the primary cylinder assembly 7 and the secondary cylinder assembly 8 act at the same time, the balance relationship is P0*S0=P1*S1+P1*S2, and the relationship between the outlet pressure P0 of the outlet port A1.13 and the regulating pressure P1 of the gas proportional pressure reducing valve 4 is P0=P1((S1+S2) / S0), which belongs to a linear function and a proportional relationship, the proportional coefficient is directly related to the size of the valve core 1.5 and the cylinder diameter of the primary cylinder assembly 7 and the secondary cylinder assembly 8, and the relationship of the proportional coefficient is calculated during design.

[0059] As shown in Figure 5The pressure regulating cycle test of the gas proportional pressure reducing valve is shown, the gas pressure of the gas proportional valve is changed from 0 bar-3 bar-0 bar, the red line in the figure is the output pressure of the gas proportional pressure reducing valve, and a pressure curve diagram in a pressure regulating range of 1.5 bar-12.5 bar is shown.

[0060] The above description of disclosed embodiments enables one of ordinary skill in the art to make and use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A novel pressure reducing valve with two-stage pressure regulation accuracy, characterized in that, The system includes a pressure regulating valve assembly (1), on the right side of which a first-stage cylinder assembly (7) and a second-stage cylinder assembly (8) are arranged in sequence. The pressure reducing valve assembly (1) includes a valve body (1.2) and a valve core (1.5) slidably connected inside the valve body (1.2). The side wall of the valve core (1.5) is provided with several protruding stop portions, which extend to the side wall of the inner cavity of the valve body (1.2). The left and right sides of the valve body (1.2) are respectively provided with a left end cap (1.1) and a right end cap (1.8). The side wall of the valve body (1.2) is respectively provided with an oil supply port P (1.11), a pressure outlet A (1.13) and an oil drain port T (1.7) communicating with the inner cavity of the valve body (1.2). A pressure sensor (1.14) is provided at the pressure outlet A (1.13). The first-stage cylinder assembly (7) includes a first-stage cylinder body (2.1) and a first-stage piston (2.2) disposed inside the first-stage cylinder body (2.1). The second-stage cylinder assembly (8) includes a second-stage cylinder body (3.3) and a second-stage piston (3.2) disposed inside the second-stage cylinder body (3.3). The valve core (1.5), the first-stage piston (2.2) and the second-stage piston (3.2) are sequentially connected and coaxially arranged. The first-stage cylinder body (2.1) and the second-stage cylinder body (3.3) are respectively fixedly connected to the right end cover (1.8). By supplying air to the left and right sides of the first-stage piston (2.2) and the second-stage piston (3.2) respectively, the valve core (1.5) can be moved left and right. The on / off state between the oil supply port P (1.11), the pressure outlet port A (1.13) and the oil drain port T (1.7) can be switched to achieve the force balance state of the left and right sides of the valve core (1.5).

2. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, When the pressure at outlet A (1.13) is 0, the pressure reducing valve is in the closed state, and air is supplied to the left side of the first-stage piston (2.2) and the second-stage piston (3.2). The first-stage piston (2.2) and the second-stage piston (3.2) are driven by the force to move the valve core (1.5) to the right. At this time, the oil supply port P (1.11) is blocked and closed by the stop part on the valve core (1.5). The outlet A (1.13) is connected to the drain port T (1.7). The oil from the oil supply port P (1.11) cannot enter the outlet A (1.13) to exert force on the valve core (1.5). At this time, the pressure at outlet A (1.13) is 0.

3. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, When the air source is supplied to the right side of the first-stage piston (2.2), the pressure reducing valve is in a low-pressure regulation state. The first-stage piston (2.2) is pushed by the force to move the valve core (1.5) to the left. At this time, the oil drain port T (1.7) is blocked and closed by the stop on the valve core (1.5). The oil supply port P (1.11) is connected to the pressure outlet port A (1.13). At the same time, the oil in the pressure outlet port A (1.13) acts on the left side of the valve core (1.5) through the pressure reducing valve, generating a rightward force F0. The right side of valve core (1.5) is pushed to the left by the first-stage piston (2.2) with force F1. When F0 and F1 are unbalanced, valve core (1.5) will be pushed to the right. When the pressure outlet A (1.13) is connected to the oil drain port T (1.7), the pressure outlet A (1.13) will drain oil into the oil drain port T (1.7). Then the pressure at the pressure outlet A (1.13) drops, and valve core (1.5) moves to the left again. This back-and-forth motion continues until both ends of valve core (1.5) are in a state of force balance.

4. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, When air is supplied to the right side of the first-stage piston (2.2) and the second-stage piston (3.2), the pressure reducing valve is in a high-pressure regulation state. The first-stage piston (2.2) is forced to push the valve core (1.5) to move to the left. The oil drain port T (1.7) is blocked and closed by the stop on the valve core (1.5). The oil supply port P (1.11) is connected to the pressure outlet port A (1.13). The oil pressure at the pressure outlet port A (1.13) increases, and the oil pressure at the pressure outlet port A (1.13) acts on the valve core (1.5). A force F0 is generated to the right on the left side. The right side of the valve core (1.5) is subjected to the thrust F1 of the first-stage piston (2.2) and the thrust F2 of the second-stage piston. When F0 is not balanced with F1+F2, the valve core (1.5) will be pushed to the right. The pressure outlet A (1.13) will drain oil to the oil drain port T (1.7). Then the pressure at the pressure outlet A (1.13) drops, and the valve core (1.5) moves to the left again. This back-and-forth motion continues until the two ends of the valve core (1.5) are in a state of force balance.

5. The novel pressure-reducing valve with two-stage pressure regulation accuracy according to claim 3 or 4, characterized in that, The F0 is equal to the pressure at the outlet A (1.13) multiplied by the force-bearing area of ​​the valve core (1.5).

6. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, The left side of the first-stage piston (2.2) and the second-stage piston (3.2) are connected in parallel to one outlet of the two-position five-way directional valve (3), and the right side of the first-stage piston (2.2) and the second-stage piston (3.2) are connected in parallel to the other outlet of the two-position five-way directional valve (3). The inlet of the two-position five-way directional valve (3) is connected to a compressed air source (2).

7. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 6, characterized in that, A gas proportional pressure reducing valve (4) is installed on the main pipeline after the first-stage piston (2.2) and the second-stage piston (3.2) are connected in parallel, and an electromagnetic switch valve (5) is installed on the branch pipeline of the second-stage piston (3.2).

8. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 7, characterized in that, The two-position five-way reversing valve (3), the air proportional pressure reducing valve (4), and the electromagnetic switch valve (5) are all connected to the controller.

9. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, The valve core (1.5) has an arc-shaped notch at the opening position of the stop part, so that there is a transition opening when the valve core (1.5) opens and closes, avoiding the impact of the valve core (1.5) when it opens or closes at the valve port position, and achieving stable output pressure.

10. The novel pressure reducing valve with two-stage pressure regulation accuracy according to claim 1, characterized in that, A plug and connecting block assembly (1.10) is provided below the valve body (1.2), and the oil supply port P (1.11) and the pressure outlet port A (1.13) pass through the plug and connecting block assembly (1.10).

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