Pressure servo valve and device adopting same

Abstract

The invention relates to the technical field of mechanical engineering, and provides a pressure servo valve and a device adopting the pressure servo valve.The pressure servo valve comprises a proportional electromagnet, a pilot valve element, a pilot valve sleeve, a pilot spring, a valve body, a main limiting structure, a main valve element and a main spring; the valve body is provided with a first space and a second space, the pilot valve and the main valve element are arranged in the first space and the second space in a sleeved mode respectively, the pilot valve element penetrates through the pilot valve sleeve, one end of the pilot valve element is connected with the proportional electromagnet, and the other end of the pilot valve element is connected with the pilot spring. One end of the main valve element is provided with a main limiting structure, and the other end of the main valve element is connected with the main spring. The pilot level is controlled by the proportional electromagnet and the spring and is matched with spring force feedback of the pilot spring to form a variable throttling opening controlled by linear displacement, and the power level forms a pressure closed loop, so that the main valve element is simple in structure and low in coaxiality requirement, and has the advantages of being good in zero position stability and low in machining cost.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical engineering, and in particular to a pressure servo valve and a device using the pressure servo valve. Background Art

[0002] Pressure servo valves precisely, quickly, and proportionally control the output load pressure based on an 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 two-stage servo valves, with either a nozzle-fender or jet-tube pilot stage. Both types require a torque motor, which is costly and suffers from poor zero-position stability, often leading to pressure deviations.

[0003] The power stage typically uses a spool valve, but the traditional main valve core is typically composed of multiple parts, such as bushings and seals on both sides. This requires multiple coaxiality requirements, is complex to manufacture, and is costly. Therefore, a low-cost pressure servo valve structure with excellent zero-position stability is urgently needed to address the shortcomings of the existing technology. Summary of the Invention

[0004] In view of the defects in the prior art, an object of the present invention is to provide a pressure servo valve and a device using the pressure servo valve.

[0005] According to the present invention, a pressure servo valve is provided, comprising a proportional solenoid, a pilot valve core, a pilot valve sleeve, a pilot spring, a valve body, a main limit structure, a main valve core and a main spring; 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 one end is connected to the proportional solenoid. The other end of the pilot valve core is connected to the pilot spring. The main valve core is arranged in the second space, and a left control chamber and a main valve spring control chamber are formed between the two ends of the main valve core and the valve body, respectively. A main limit structure is arranged in the left control chamber, and the main spring is arranged in the main valve spring control chamber. The end of the main valve core is connected to the main spring. When the proportional solenoid is energized, it can drive the pilot valve core to move in the direction of the pilot spring and thus adjust the oil pressure entering the left control chamber, thereby achieving precise position control of the main valve core.

[0006] Preferably, the interior of the pilot valve sleeve is provided with a first annular groove and a second annular groove, the first annular groove and the second annular groove are arranged at intervals, and an axial groove is provided on the pilot valve core, the axial groove and the first annular groove form a variable throttle port, when the proportional solenoid is energized, the pilot valve core can be driven to move in the direction of the pilot spring and thus the opening of the variable throttle port can be adjusted, thereby adjusting the oil pressure entering the left control chamber and realizing the precise position control of the main valve core.

[0007] Preferably, the valve body is provided with an oil inlet circuit and an oil return circuit, the oil inlet circuit comprising a first oil inlet main pipe and a first oil inlet branch pipe and a second oil inlet branch pipe connected to the end of the first oil inlet main pipe, the end of the first oil inlet branch pipe being connected to the variable throttle port, and the end of the second oil inlet branch pipe being connected to the left control chamber; The oil return circuit includes a first oil return main pipe and a first oil return branch pipe and a second oil return branch pipe connected to the first oil return main pipe. The first oil return branch pipe is connected to the pilot spring chamber, the second oil return branch pipe is connected to the second annular groove, and the first oil return main pipe is connected to the outside.

[0008] Preferably, a filter and a fixed throttle hole are sequentially provided on the first oil inlet main pipe along the direction of oil flow.

[0009] Preferably, a third annular groove is provided on the main valve core and a flow channel is provided 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.

[0010] Preferably, a control oil circuit is provided on the valve body, and the control oil circuit is connected to the third annular groove.

[0011] Preferably, the axial groove on the pilot valve core can be designed to have different widths to match the control of the control oil circuit pressure by the hydraulic bridge composed of the fixed throttle hole and the variable throttle port.

[0012] Preferably, there is a main limit structure on the left side of the main valve core. Under the action of the main spring, the main valve core is initially in contact with the main limit structure. At this time, the third annular groove is connected to the return oil circuit and the pressure control oil circuit.

[0013] Preferably, the pilot valve core and the pilot valve sleeve are in sealed sliding fit.

[0014] According to the present invention, a device using a pressure servo valve is provided, which uses the pressure servo valve.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The pilot stage in the present invention is controlled by a proportional electromagnet and a spring. The low-cost proportional electromagnet is combined with the spring force feedback of the pilot spring to form a variable throttle for linear displacement control. The power stage itself forms a pressure closed loop, and there is no need for closed-loop control through a load-end sensor. This makes the main valve core structure simple, with fewer coaxiality requirements, and has the advantages of good zero-position stability and low processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings: Figure 1 It is a schematic diagram of the structural cross-section of the present invention.

[0017] The figure shows: Proportional solenoid 1; Pilot valve core 2; Pilot valve sleeve 3; First annular groove 4; Second annular groove 5; Axial groove 6; Pilot spring 7; pilot spring chamber 8; Fixed throttle hole 9; Valve body 10; left control chamber 11; filter 12; Main limiting structure 13; Main valve core 14; third annular groove 141; Runner 15; Main valve spring control chamber 16; Main spring 17; Oil inlet line 200; First oil inlet main 201; First oil inlet branch pipe 202; Second oil inlet branch pipe 203; Oil return line 300; The first oil return main 301; First oil return branch pipe 302; Second oil return branch pipe 303; Control oil circuit 400. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0019] The present invention provides a pressure servo valve, including a proportional solenoid 1, a pilot valve core 2, a pilot valve sleeve 3, a pilot spring 7, a valve body 10, a main limit 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 arranged in the first space and forms a pilot spring cavity 8 between the pilot valve sleeve 3 and the valve body 10, the pilot spring 7 is arranged in the pilot spring cavity 8, the pilot valve core 2 passes through the pilot valve sleeve 3 and one end is connected to the proportional solenoid 1, and the other end of the pilot valve core 2 is connected to the pilot spring 7.

[0020] Furthermore, the main valve core 14 is arranged in the second space and forms a left control chamber 11 and a main valve spring control chamber 16 between its two ends and the valve body 10 respectively. A main limit structure 13 is arranged in the left control chamber 11. The main limit structure 13 is used to provide a limit for the stroke of the main valve core 14 moving toward the left control chamber 11. The main spring 17 is arranged 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.

[0021] The interior of the pilot valve sleeve 3 is provided with a first annular groove 4 and a second annular groove 5, and the first annular groove 4 and the second annular groove 5 are arranged at intervals. An axial groove 6 is provided on the pilot valve core 2, and the right side of the axial groove 6 and the left side of the first annular groove 4 form a variable throttle. 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 adjustable.

[0022] A third annular groove 141 is provided on the main valve core 14 and a flow channel 15 is provided 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 solenoid 1 is energized, it can drive the pilot valve core 2 to move in the direction of the pilot spring 7 and thus can adjust the opening of the variable throttle port and then can adjust the oil pressure entering the left control chamber 11, so as to realize the precise position control of the main valve core 14.

[0023] like Figure 1As shown, the valve body 10 is also provided with an oil inlet circuit 200, an oil return circuit 300 and a control oil circuit 400. The oil inlet circuit 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. A filter 12 and a fixed throttle hole 9 are sequentially provided on the first oil inlet main pipe 201 along the direction of oil flow. 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 oil return circuit 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, the second oil return branch pipe 303 is connected to the second annular groove 5, and the first oil return main pipe 301 is connected to the outside.

[0024] It should be noted that the width of the axial groove 6 on the pilot valve core 2 is determined by the control characteristics of the hydraulic bridge circuit formed by the fixed throttle hole 9 and the variable throttle orifice, thereby controlling the pressure in the control oil circuit 400. A larger variable throttle orifice means more oil flows from the first oil inlet branch pipe 202 through the variable throttle orifice, the axial groove 6, and the second annular groove 5, and into the second oil return branch pipe 303. At this point, the pressure of the oil entering the second oil inlet branch pipe 203 is lower than that of the first oil main inlet pipe 201. Therefore, the oil pressure in the second oil inlet branch pipe 203 can be adjusted by adjusting the size of the variable throttle orifice.

[0025] like Figure 1 As shown, there is a main limit structure 13 on the left side of the main valve core 14. Under the action of the main spring 17, the main valve core 14 is initially in contact with the main limit structure 13. At this time, the third annular groove 141 connects the return oil circuit 300 and the control oil circuit 400.

[0026] The present invention also provides a device using a pressure servo valve, which can be a variety of equipment, for example, the device can be an injection molding machine, a press, a CNC machine tool, a material testing machine, and for another example, the device can also be an aircraft landing gear retraction system; for another example, the device can also be a variable pitch system in a wind turbine, a steering gear control system in a ship, and can also be a rolling mill, continuous casting machine and other devices, all of which can achieve precise control.

[0027] The pilot stage in this invention utilizes a low-cost proportional electromagnet 1, coupled with spring force feedback from a pilot spring 7, to form a variable throttle with linear displacement control, replacing the less stable nozzle-flap valves and jet tube valves. The present invention can utilize the proportional electromagnet 1 because pressure servo valves differ fundamentally from flow servo valves. Their dynamic performance is closely related to the volume of the load chamber. The power stage itself forms a closed-loop pressure loop, eliminating the need for closed-loop control via a load-side sensor. Therefore, the high-frequency displacement of the valve core is determined by the load, not the pilot valve. Even though conventional pressure servo valves utilize high-frequency-response nozzle-flap valves and jet tube valves, their load dynamic characteristics are still relatively low, wasting their high-frequency advantages. Therefore, replacing these valves with the proportional electromagnet 1 can still meet the requirements of pressure servo valves. The power stage optimizes the traditional main valve core structure by eliminating unnecessary bushing structures that require coaxiality, thereby reducing costs.

[0028] The working principle of the present invention is as follows: When the input current is supplied to the proportional solenoid 1, the thrust generated by the proportional solenoid 1 on the pilot valve core 2 and the elastic force feedback of the pilot spring 7 jointly determine the displacement of the pilot valve core 2. The working edges of the pilot valve core 2 and the pilot valve sleeve 3 form a pilot variable throttle. The fixed throttle hole 9 and the pilot variable throttle hole form a hydraulic bridge circuit, forming a linearly controllable pilot control pressure behind the fixed throttle hole 9 and acting 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 to form a force balance with the pilot control pressure, thereby achieving output pressure control. The present invention solves the problems of the traditional pressure servo valve main valve having a complex structure and high processing difficulty, and also solves the problem that the traditional pressure servo valve is prone to zero position offset after use.

[0029] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and 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, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0030] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A pressure servo valve, characterized in that: It includes a proportional solenoid (1), a pilot valve core (2), a pilot valve sleeve (3), a pilot spring (7), a valve body (10), a main limit 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 arranged in the first space and forms a pilot spring chamber (8) with the valve body (10), the pilot spring (7) is arranged in the pilot spring chamber (8), the pilot valve core (2) passes through the pilot valve sleeve (3) and one end is connected to the proportional solenoid (1), and the other end of the pilot valve core (2) is connected to the pilot spring (7); The main valve core (14) is arranged in the second space and forms a left control chamber (11) and a main valve spring control chamber (16) between its two ends and the valve body (10), a main limit structure (13) is arranged in the left control chamber (11), the main spring (17) is arranged in the main valve spring control chamber (16), and the end of the main valve core (14) is connected to the main spring (17); When the proportional solenoid (1) is energized, it can drive the pilot valve core (2) to move in the direction of the pilot spring (7), thereby adjusting the oil pressure entering the left control chamber (11), thereby achieving precise position control of the main valve core (14).

2. The pressure servo valve according to claim 1, characterized in that: The interior of the pilot valve sleeve (3) is provided with a first annular groove (4) and a second annular groove (5), the first annular groove (4) and the second annular groove (5) are arranged at intervals, and the pilot valve core (2) is provided with an axial groove (6), the axial groove (6) and the first annular groove (4) form a variable throttle. When the proportional electromagnet (1) is energized, the pilot valve core (2) can be driven to move in the direction of the pilot spring (7), thereby regulating the opening of the variable throttle, thereby regulating the oil pressure entering the left control chamber (11), and realizing the precise position regulation of the main valve core (14).

3. The pressure servo valve according to claim 2, characterized in that: The valve body (10) is provided with an oil inlet circuit (200) and an oil return circuit (300). The oil inlet circuit (200) comprises a first oil inlet main pipe (201), a first oil inlet branch pipe (202) and a second oil inlet branch pipe (203) connected to the ends 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 oil return circuit (300) comprises a first oil return main pipe (301), a first oil return branch pipe (302) and a second oil return branch pipe (303) connected to the first oil return main pipe (301), wherein the first oil return branch pipe (302) is connected to the pilot spring chamber (8), the second oil return branch pipe (303) is connected to the second annular groove (5), and the first oil return main pipe (301) is connected to the outside.

4. The pressure servo valve according to claim 3, characterized in that: A filter (12) and a fixed throttle hole (9) are sequentially provided on the first oil inlet main pipe (201) along the direction of oil flow.

5. The pressure servo valve according to claim 4, 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).

6. The pressure servo valve according to claim 5, characterized in that: A control oil circuit (400) is provided on the valve body (10), and the control oil circuit (400) is connected to the third annular groove (141).

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

8. The pressure servo valve according to claim 6, characterized in that: A main limiting structure (13) is provided on the left side of the main valve core (14). Under the action of the main spring (17), the main valve core (14) is initially in contact with the main limiting structure (13). At this time, the third annular groove (141) is connected to the return oil circuit (300) and the pressure control oil circuit (400).

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

10. A device using a pressure servo valve, characterized in that: The pressure servo valve according to any one of claims 1 to 9 is used.

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