Pressure servo valve and device using pressure servo valve

Abstract

This invention relates to the field of mechanical engineering technology, and provides a pressure servo valve and a device using the pressure servo valve. The pressure servo valve includes a proportional electromagnet, a pilot valve core, a pilot valve sleeve, a pilot spring, a valve body, a main limiting structure, a main valve core, and a main spring. The valve body has a first space and a second space. The pilot valve and the main valve core are respectively fitted into the first space and the second space. The pilot valve core passes through the pilot valve sleeve and is connected at one end to the proportional electromagnet and at the other end to the pilot spring. One end of the main valve core is equipped with the main limiting structure, and the other end of the main valve core is connected to the main spring. In this invention, the pilot stage uses a proportional electromagnet and spring control, and the spring force feedback of the pilot spring forms a variable throttling orifice for linear displacement control. The power stage itself forms a pressure closed loop, which makes the main valve core structure simple, requires less coaxiality, and has the advantages of good zero-position stability and low processing cost.

Description

Technical Field

[0001] This invention relates to the field of mechanical engineering technology, and more specifically, to a pressure servo valve and an apparatus using a pressure servo valve. Background Technology

[0002] Pressure servo valves precisely, quickly, and proportionally control the pressure of the output load based on the input electrical signal. They are widely used in applications requiring extremely high dynamic response and precision in force or pressure control. Pressure servo valves are typically two-stage servo valves, with the pilot stage being either a nozzle-baffle type or a jet tube type. Both types require a torque motor, resulting in high cost and poor zero-position stability, frequently leading to control pressure deviations.

[0003] Power stages typically employ spool valves, but traditional main valve cores usually consist of multiple parts, such as side bushings and seals. These components require high coaxiality, are complex to manufacture, and are costly. Therefore, there is an urgent need to design a low-cost pressure servo valve structure with good zero-position stability to overcome the shortcomings of existing technologies. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of this invention is to provide a pressure servo valve and an apparatus using a pressure servo valve.

[0005] A pressure servo valve according to the present invention includes a proportional electromagnet, a pilot valve core, a pilot valve sleeve, a pilot spring, a valve body, a main limiting structure, a main valve core, and a main spring.

[0006] The valve body has a first space and a second space. The pilot valve sleeve is disposed in the first space and forms a pilot spring cavity with the valve body. The pilot spring is disposed in the pilot spring cavity. The pilot valve core passes through the pilot valve sleeve and is connected at one end to the proportional electromagnet. The other end of the pilot valve core is connected to the pilot spring.

[0007] The main valve core is disposed in the second space and its two ends form a left control cavity and a main valve spring control cavity with the valve body respectively. A main limiting structure is disposed in the left control cavity, and the main spring is disposed in the main valve spring control cavity. The end of the main valve core is connected to the main spring.

[0008] When the proportional electromagnet is energized, it can drive the pilot valve core to move toward the pilot spring, thereby regulating the oil pressure entering the left control chamber and thus enabling precise control of the main valve core position.

[0009] Preferably, the pilot valve sleeve is internally configured with a first annular groove and a second annular groove, which are spaced apart. The pilot valve core is provided with an axial groove, which forms a variable throttle orifice with the first annular groove. When the proportional electromagnet is energized, it can drive the pilot valve core to move toward the pilot spring, thereby adjusting the opening of the variable throttle orifice and thus regulating the oil pressure entering the left control chamber, thereby achieving precise control of the main valve core position.

[0010] Preferably, the valve body is provided with an oil inlet passage and an oil return passage. The oil inlet passage includes a first main oil inlet pipe and a first branch oil inlet pipe and a second branch oil inlet pipe connected to the end of the first main oil inlet pipe. The end of the first branch oil inlet pipe is connected to the variable throttle port, and the end of the second branch oil inlet pipe is connected to the left control chamber.

[0011] The return oil circuit includes a first return oil main pipe and a first return oil branch pipe and a second return oil branch pipe connected to the first return oil main pipe. The first return oil branch pipe is connected to the pilot spring cavity, the second return oil branch pipe is connected to the second annular groove, and the first return oil main pipe is connected to the outside.

[0012] Preferably, a filter and a fixed throttling orifice are sequentially provided on the first oil inlet main pipe along the direction of oil flow.

[0013] Preferably, the main valve core is provided with a third annular groove and has a flow channel inside, one end of the flow channel is connected to the third annular groove, and the other end of the flow channel is connected to the main valve spring control chamber.

[0014] Preferably, the valve body is provided with a control oil circuit, which is connected to the third annular groove.

[0015] Preferably, the axial grooves on the pilot valve core can be designed with different widths to match the control of the control oil circuit pressure by the hydraulic bridge circuit composed of the fixed throttle orifice and the variable throttle port.

[0016] Preferably, the main valve core has a main limiting structure on the left side. Under the action of the main spring, the main valve core is initially positioned at the point of contact and abutment with the main limiting structure. At this time, the third annular groove connects the return oil circuit and the pressure control oil circuit.

[0017] Preferably, the pilot valve core and the pilot valve sleeve are in a sealed sliding fit.

[0018] According to the present invention, an apparatus employing a pressure servo valve is provided, wherein the pressure servo valve is used.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The pilot stage in this invention uses a proportional electromagnet with spring control. The low-cost proportional electromagnet, combined with the spring force feedback of the pilot spring, forms a variable throttle orifice for linear displacement control. The power stage itself forms a pressure closed loop, eliminating the need for closed-loop control through load-side sensors. This results in a simple main valve core structure, fewer coaxiality requirements, and advantages such as good zero-position stability and low processing cost. Attached Figure Description

[0021] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0022] Figure 1 This is a schematic cross-sectional view of the structure of the present invention.

[0023] The diagram shows:

[0024] Proportional electromagnet 1;

[0025] Pilot valve core 2;

[0026] Pilot valve sleeve 3;

[0027] First annular groove 4;

[0028] Second annular groove 5;

[0029] Axial groove 6;

[0030] Pilot spring 7;

[0031] Pilot spring cavity 8;

[0032] Fixed throttling orifice 9;

[0033] Valve body 10;

[0034] Left control cavity 11;

[0035] Filter 12;

[0036] Main limiting structure 13;

[0037] Main valve core 14;

[0038] Third annular groove 141;

[0039] Flow channel 15;

[0040] Main valve spring control chamber 16;

[0041] Main spring 17;

[0042] Oil inlet line 200;

[0043] First oil inlet main pipe 201;

[0044] First oil inlet manifold 202;

[0045] Second oil inlet pipe 203;

[0046] Return oil line 300;

[0047] First oil return main pipe 301;

[0048] First return oil distribution pipe 302;

[0049] Second return oil distribution pipe 303;

[0050] Control the oil circuit 400. Detailed Implementation

[0051] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0052] This invention provides a pressure servo valve, including a proportional electromagnet 1, a pilot valve core 2, a pilot valve sleeve 3, a pilot spring 7, a valve body 10, a main limiting structure 13, a main valve core 14, and a main spring 17; the valve body 10 has a first space and a second space, the pilot valve sleeve 3 is disposed in the first space and forms a pilot spring cavity 8 between it and the valve body 10, the pilot spring 7 is disposed in the pilot spring cavity 8, the pilot valve core 2 passes through the pilot valve sleeve 3 and is connected at one end to the proportional electromagnet 1, and the other end of the pilot valve core 2 is connected to the pilot spring 7.

[0053] Furthermore, the main valve core 14 is disposed in the second space and its two ends form a left control chamber 11 and a main valve spring control chamber 16 between the valve body 10, respectively. A main limiting structure 13 is disposed in the left control chamber 11. The main limiting structure 13 is used to limit the stroke of the main valve core 14 moving toward the left control chamber 11. The main spring 17 is disposed in the main valve spring control chamber 16. The end of the main valve core 14 is connected to the main spring 17. The main spring 17 is used to provide elastic damping when the main valve core 14 moves toward the main valve spring control chamber 16.

[0054] The pilot valve sleeve 3 is internally configured with a first annular groove 4 and a second annular groove 5, which are arranged at intervals. The pilot valve core 2 is provided with an axial groove 6. The right side of the axial groove 6 and the left side of the first annular groove 4 form a variable throttle orifice. When the pilot valve core 2 slides in the pilot valve sleeve 3, the axial groove 6 and the first annular groove 4 may not be connected, may be fully connected, or may only be partially connected, thereby making the hydraulic flow of the variable throttle orifice adjustable.

[0055] The main valve core 14 is provided with a third annular groove 141 and has a flow channel 15 inside. One end of the flow channel 15 is connected to the third annular groove 141, and the other end of the flow channel 15 is connected to the main valve spring control chamber 16. When the proportional electromagnet 1 is energized, it can drive the pilot valve core 2 to move toward the pilot spring 7, thereby adjusting the opening of the variable throttle orifice and regulating the oil pressure entering the left control chamber 11, thus achieving precise control of the position of the main valve core 14.

[0056] like Figure 1 As shown, the valve body 10 is also equipped with an oil inlet passage 200, an oil return passage 300, and a control passage 400. The oil inlet passage 200 includes a first oil inlet main pipe 201 and a first oil inlet branch pipe 202 and a second oil inlet branch pipe 203 connected to the end of the first oil inlet main pipe 201. Along the direction of oil flow, a filter 12 and a fixed throttling orifice 9 are sequentially arranged on the first oil inlet main pipe 201. The end of the first oil inlet branch pipe 202 is connected to a variable throttling orifice, and the end of the second oil inlet branch pipe 203 is connected to the left control chamber 11. The oil return passage 300 includes a first oil return main pipe 301 and a first oil return branch pipe 302 and a second oil return branch pipe 303 connected to the first oil return main pipe 301. The first oil return branch pipe 302 is connected to the pilot spring chamber 8, and the second oil return branch pipe 303 is connected to the second annular groove 5. The first oil return main pipe 301 is connected to the outside.

[0057] It should be noted that the width of the axial groove 6 on the pilot valve core 2 depends on the control characteristics of the hydraulic bridge circuit composed of the fixed throttle orifice 9 and the variable throttle port, thereby controlling the pressure of the control oil circuit 400. The larger the variable throttle port, the more oil enters the second return oil branch pipe 303 from the first oil inlet branch pipe 202 through the variable throttle port, the axial groove 6, and the second annular groove 5. At this time, the pressure of the oil entering the second oil inlet branch pipe 203 is lower than that of the first oil inlet main pipe 201. Therefore, the hydraulic pressure of the oil in the second oil inlet branch pipe 203 can be adjusted by adjusting the size of the variable throttle port.

[0058] like Figure 1 As shown, there is a main limiting structure 13 on the left side of the main valve core 14. Under the action of the main spring 17, the initial position of the main valve core 14 is in contact with the main limiting structure 13. At this time, the third annular groove 141 connects the return oil circuit 300 and the control oil circuit 400.

[0059] The present invention also provides a device using a pressure servo valve. The device can be a variety of equipment, such as an injection molding machine, a press, a CNC machine tool, a material testing machine, an aircraft landing gear retraction system, a pitch control system in a wind turbine, a ship's steering gear control system, a rolling mill, a continuous casting machine, etc., all of which can achieve precise control.

[0060] In this invention, the pilot stage employs a low-cost proportional electromagnet 1 paired with a pilot spring 7 to form a linear displacement-controlled variable throttling orifice, replacing the less stable nozzle-baffle valve and jet valve. The reason this invention can use the proportional electromagnet 1 is that pressure servo valves and flow servo valves are fundamentally different; their dynamic performance is closely related to the load chamber volume. Their power stage itself forms a pressure closed loop, eliminating the need for closed-loop control via a load-side sensor. Therefore, the high-frequency displacement of their valve core depends on the load, not the pilot valve. Even if traditional pressure servo valves use high-frequency-response nozzle-baffle valves and jet valves, their load dynamic characteristics remain low, wasting the high-frequency advantages of these valves. Therefore, replacing nozzle-baffle valves and jet valves with the proportional electromagnet 1 still meets the requirements of pressure servo valves. The power stage optimizes the traditional main valve core structure by eliminating unnecessary bushing structures with coaxiality requirements, thus reducing costs.

[0061] The working principle of this invention is as follows:

[0062] When the input current is supplied to the proportional electromagnet 1, the proportional electromagnet 1 generates a thrust on the pilot valve core 2, which, together with the spring force feedback of the pilot spring 7, determines the displacement of the pilot valve core 2. The working sides of the pilot valve core 2 and the pilot valve sleeve 3 form a pilot variable throttle orifice. The fixed throttle orifice 9 and the pilot variable throttle orifice form a hydraulic bridge circuit. A linearly controllable pilot control pressure is formed on the rear side of the fixed throttle orifice 9 and acts on the left end of the main valve core 14. The final control pressure acts on the right end of the main valve core 14 and forms a force balance with the pilot control pressure, thereby achieving control of the output pressure. This invention solves the problems of complex main valve structure and high processing difficulty in traditional pressure servo valves, and also solves the problem of easy zero-position deviation after use in traditional pressure servo valves.

[0063] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0064] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A pressure servo valve, characterized in that, It includes a proportional electromagnet (1), a pilot valve core (2), a pilot valve sleeve (3), a pilot spring (7), a valve body (10), a main limiting structure (13), a main valve core (14), and a main spring (17). The valve body (10) has a first space and a second space. The pilot valve sleeve (3) is disposed in the first space and forms a pilot spring cavity (8) between it and the valve body (10). The pilot spring (7) is disposed in the pilot spring cavity (8). The pilot valve core (2) passes through the pilot valve sleeve (3) and is connected at one end to the proportional electromagnet (1). The other end of the pilot valve core (2) is connected to the pilot spring (7). The main valve core (14) is disposed in the second space and its two ends form a left control cavity (11) and a main valve spring control cavity (16) between the valve body (10) and its two ends, respectively. A main limiting structure (13) is disposed in the left control cavity (11), and the main spring (17) is disposed in the main valve spring control cavity (16). The end of the main valve core (14) is connected to the main spring (17). When the proportional electromagnet (1) is energized, it can drive the pilot valve core (2) to move toward the pilot spring (7), thereby regulating the oil pressure entering the left control chamber (11) and thus enabling precise control of the position of the main valve core (14). The pilot valve sleeve (3) is internally configured with a first annular groove (4) and a second annular groove (5), which are spaced apart. The pilot valve core (2) is provided with an axial groove (6), which forms a variable throttle orifice with the first annular groove (4). When the proportional electromagnet (1) is energized, it can drive the pilot valve core (2) to move toward the pilot spring (7), thereby adjusting the opening of the variable throttle orifice and thus adjusting the oil pressure entering the left control chamber (11), thereby achieving precise control of the position of the main valve core (14). The valve body (10) is provided with an oil inlet passage (200) and an oil return passage (300). The oil inlet passage (200) includes a first oil inlet main pipe (201) and a first oil inlet branch pipe (202) and a second oil inlet branch pipe (203) connected to the end of the first oil inlet main pipe (201). The end of the first oil inlet branch pipe (202) is connected to the variable throttle port, and the end of the second oil inlet branch pipe (203) is connected to the left control chamber (11). The return oil circuit (300) includes a first return oil main pipe (301) and a first return oil branch pipe (302) and a second return oil branch pipe (303) connected to the first return oil main pipe (301). The first return oil branch pipe (302) is connected to the pilot spring cavity (8), and the second return oil branch pipe (303) is connected to the second annular groove (5). The first return oil main pipe (301) is connected to the outside.

2. The pressure servo valve according to claim 1, characterized in that, Along the direction of oil flow, the first oil inlet pipe (201) is sequentially provided with a filter (12) and a fixed throttling hole (9).

3. The pressure servo valve according to claim 2, characterized in that, The main valve core (14) is provided with a third annular groove (141) and has a flow channel (15) inside. One end of the flow channel (15) is connected to the third annular groove (141), and the other end of the flow channel (15) is connected to the main valve spring control chamber (16).

4. The pressure servo valve according to claim 3, characterized in that, The valve body (10) is provided with a control oil passage (400), which is connected to the third annular groove (141).

5. The pressure servo valve according to claim 4, characterized in that, The axial groove (6) on the pilot valve core (2) can be designed with different widths to match the control of the control oil circuit (400) pressure by the hydraulic bridge circuit composed of the fixed throttle orifice (9) and the variable throttle orifice.

6. The pressure servo valve according to claim 4, characterized in that, The main valve core (14) has a main limiting structure (13) on the left side. Under the action of the main spring (17), the main valve core (14) is initially positioned at the point of contact and abutment with the main limiting structure (13). At this time, the third annular groove (141) connects the return oil circuit (300) and the pressure control oil circuit (400).

7. The pressure servo valve according to claim 1, characterized in that, The pilot valve core (2) and the pilot valve sleeve (3) are in a sealed sliding fit.

8. A device employing a pressure servo valve, characterized in that, The pressure servo valve according to any one of claims 1 to 7 is used.

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