A mechanical feedback nozzle-poppet servo valve that suppresses pre-stage vortex shedding

Abstract

This invention relates to a mechanical feedback nozzle-baffle servo valve for suppressing vortex oscillation in the pre-stage, comprising a torque motor, a pre-stage, and a main stage. The torque motor includes a magnetic conductor, a baffle, a feedback rod, a coil, an armature, and a permanent magnet. The pre-stage includes a pre-stage valve body, a bushing, and a nozzle. The main stage includes a main-stage valve body and a valve core. Compared with the prior art, this invention addresses the vortex oscillation phenomenon in the baffle wake region. Based on the relationship between the vortex oscillation frequency and the width of the flow field, a mechanical feedback nozzle-baffle servo valve for suppressing vortex oscillation in the pre-stage is designed. A bushing structure is added to the wake region of the baffle in the pre-stage of the servo valve to limit the flow field width at the bottom of the baffle, effectively suppressing vortex oscillation in the pre-stage of the servo valve, reducing noise and vibration, and improving the service life of the electro-hydraulic servo valve.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control valve technology, and in particular to a mechanical feedback nozzle-baffle servo valve for suppressing vortex oscillation in the pre-stage. Background Technology

[0002] Electro-hydraulic servo valves are key components affecting the performance of hydraulic servo systems. They connect the electrical and hydraulic components to achieve electro-hydraulic conversion and power amplification. Among these, nozzle-baffle servo valves were researched earlier and are characterized by fast dynamic response, high sensitivity, good linearity, and minimal temperature and pressure drift. They are widely used in CNC machine tools, locomotives, ships, radar, aircraft, and other automated control equipment requiring high precision. To meet application demands, nozzle-baffle servo valves are becoming increasingly smaller, while the core velocity of the jet in the pre-stage is increasing. The high-speed jet exits from the nozzle, and most of the fluid flows along the baffle towards the wake region, where it separates at the baffle tail, forming two rows of vortices. As the Reynolds number of the fluid increases, periodically alternating vortices form on both sides of the baffle, generating flow field pressure pulsations and causing self-excited oscillations in the servo valve's pre-stage. These self-excited oscillations generate high-frequency noise, and due to the alternating stress caused by the oscillations, the Bourdon tube may experience fatigue fracture, leading to servo valve failure.

[0003] To suppress the self-excited oscillation phenomenon in the pre-stage of a nozzle-baffle servo valve, Chinese patent CN 206929154 U discloses a device for suppressing self-excited oscillation of a servo valve with adjustable nozzle-baffle distance; Chinese patent CN 207961119 U discloses a nozzle-baffle servo valve for suppressing cavitation in the pre-stage; and Chinese patent CN 114893474 B discloses a method for suppressing self-excited oscillation of a dual-nozzle-baffle servo valve. All of these patents suppress the oscillation phenomenon of the local flow field between the nozzle and the baffle through structural innovation, but they cannot meet the requirements for suppressing the vortex oscillation phenomenon in the baffle wake region. Summary of the Invention

[0004] The purpose of this invention is to provide a mechanical feedback nozzle-baffle servo valve that suppresses vortex oscillation in the pre-stage of the nozzle-baffle servo valve, thereby effectively suppressing the vortex oscillation phenomenon in the pre-stage of the servo valve, reducing noise and vibration, and improving service life.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A mechanical feedback nozzle-baffle servo valve for suppressing vortex shedding in the pre-stage includes a torque motor, a pre-stage, and a main stage. The torque motor includes a magnetic conductor, a baffle, a feedback rod, a coil, an armature, and a permanent magnet. The pre-stage includes a pre-stage valve body, a bushing, and a nozzle. The main stage includes a main stage valve body and a valve core.

[0007] The pre-stage valve body is provided with two vertically symmetrical magnetic conductors, an armature is provided between the two magnetic conductors, a permanent magnet is provided between the armature and the magnetic conductors, and two sets of horizontally symmetrical coils are provided between the permanent magnet and the magnetic conductors.

[0008] One end of the feedback rod is connected to the middle of the armature, and the other end of the feedback rod is connected to the valve core in the main valve body. Baffles are provided on both sides of the feedback rod, and bushings are provided below the baffles. A nozzle is provided at the end of the baffle away from the feedback rod.

[0009] The permanent magnet is used to magnetize the upper and lower magnetic conductors into N poles and S poles, forming a fixed magnetic field. When the coil is energized, the armature will deflect in a counterclockwise or clockwise direction, thereby driving the baffle to move.

[0010] Furthermore, the torque motor also includes a spring tube, the armature is press-fitted to the spring tube, the armature is fixed above the pre-stage valve body by the spring tube, and the spring tube is used to position the armature in the middle of the symmetrical magnetic conductors.

[0011] As a preferred technical solution, the spring tube is disposed on the axis of the armature.

[0012] Furthermore, the feedback rod is press-fitted into the spring tube via a baffle.

[0013] As a preferred technical solution, the lower end of the feedback rod is spherical and is embedded in the middle groove of the valve core.

[0014] Furthermore, the main stage also includes a valve sleeve, which is disposed on the main stage valve body. The valve sleeve and the main stage valve body are symmetrically arranged with two inlet ports, two return ports, two control ports, and corresponding flow channels.

[0015] Furthermore, the valve sleeve is provided with a return oil throttling hole, which is located below the valve core and serves as the bottom of the pre-stage flow field.

[0016] Furthermore, the main stage also includes an oil filter, which is located in the control flow channel of the main stage valve body. The oil filter has a fixed throttling orifice at each end, and the two fixed throttling orifices are respectively connected to two control flow channels inside the main stage valve body. The two control flow channels are connected to the ports at both ends of the valve core.

[0017] Furthermore, the two nozzles are symmetrically installed on both sides of the baffle by press fitting. The two nozzles and the planes on both sides of the baffle form two variable throttling orifices, and the size of the variable throttling orifices can be adjusted by deflecting the baffle.

[0018] Furthermore, the pre-stage valve body is provided with two symmetrical nozzle chambers, which are symmetrically arranged on both sides of the baffle, and the two nozzles are respectively arranged in one nozzle chamber.

[0019] Furthermore, the nozzle cavity is provided with a plug at the end away from the nozzle.

[0020] Furthermore, the inner side of the bushing near the baffle is machined with rounded corners, the inner diameter of the bushing is consistent with the inner diameter of the main valve body, the outer diameter of the bushing is consistent with the inner diameter of the pre-stage valve body, and the bushing is connected to the inside of the pre-stage valve body by press fitting.

[0021] Furthermore, the bushing is provided with a sealing ring on its exterior to seal against the pre-stage valve body.

[0022] The working principle of this invention is as follows:

[0023] The pressure at both ends of the main valve core of this invention depends on the control pressure difference between the two chambers of the main valve core acting on the control flow channel. The control pressure in the two control flow channels depends on the size of the variable throttling orifice formed between the nozzle and the baffle. Different sizes of the variable throttling orifice on the left and right sides result in different pressure losses, creating a pressure difference between the left and right sides of the main valve core, which drives the movement of the main valve core.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention starts from the vortex oscillation phenomenon in the wake region of a baffle. Based on the relationship between the vortex oscillation frequency and the width of the flow field, a mechanical feedback nozzle-baffle servo valve is designed to suppress vortex oscillation in the pre-stage. A bushing structure is added to the wake region of the baffle in the pre-stage of the servo valve to limit the width of the flow field at the bottom of the baffle, which can effectively suppress the vortex oscillation phenomenon in the pre-stage of the servo valve, reduce noise and vibration, and improve the service life of the electro-hydraulic servo valve. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the mechanical feedback nozzle-baffle servo valve in this invention;

[0027] Figure 2 The simulation verification speed cloud diagram is for this invention.

[0028] Explanation of the attached diagram numbers: 1. Magnetic conductor, 2. Bourdon tube, 3. Baffle, 4. Bushing, 5. Sealing ring, 6. Feedback rod, 7. Return oil throttle orifice, 8. Oil filter, 9. Coil, 10. Armature, 11. Permanent magnet, 12. Nozzle, 13. Plug, 14. Valve sleeve, 15. Valve core, 16. Fixed throttle orifice. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0031] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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 the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] Example 1

[0035] See Figure 1This embodiment provides a mechanical feedback nozzle-baffle servo valve for suppressing vortex oscillation in the pre-stage. The mechanical feedback nozzle-baffle servo valve for suppressing vortex oscillation in the pre-stage includes a torque motor, a pre-stage, and a main stage. The torque motor includes a magnetic conductor 1, a baffle 3, a feedback rod 6, a coil 9, an armature 10, and a permanent magnet 11. The pre-stage includes a pre-stage valve body, a bushing 4, and a nozzle 12. The main stage includes a main stage valve body and a valve core 15.

[0036] The pre-stage valve body is provided with two vertically symmetrical magnetic conductors 1, an armature 10 is provided between the two magnetic conductors 1, a permanent magnet 11 is provided between the armature 10 and the magnetic conductors 1, and two sets of horizontally symmetrical coils 9 are provided between the permanent magnet 11 and the magnetic conductors 1.

[0037] One end of the feedback rod 6 is connected to the middle of the armature 10, and the other end of the feedback rod 6 is connected to the valve core 15 in the main valve body. Baffles 3 are provided on both sides of the feedback rod 6, and bushings 4 are provided below the baffles 3. A nozzle 12 is provided at the end of the baffle 3 away from the feedback rod 6.

[0038] The permanent magnet 11 is used to magnetize the upper and lower magnetic conductors 1 into N poles and S poles to form a fixed magnetic field. When the coil 9 is energized, the armature 10 will deflect in a counterclockwise or clockwise direction, thereby driving the baffle 3 to move.

[0039] In this embodiment, the torque motor further includes a spring tube 2, the armature 10 is press-fitted together with the spring tube 2, the armature 10 is fixed above the pre-stage valve body through the spring tube 2, and the spring tube 2 is used to position the armature 10 in the middle of the symmetrical magnetic conductors 1.

[0040] In this embodiment, the spring tube 2 is disposed on the axis of the armature 10.

[0041] In this embodiment, the feedback rod 6 is pressed into the inside of the spring tube 2 by the baffle 3.

[0042] In this embodiment, the lower end of the feedback rod 6 is spherical and is embedded in the middle groove of the valve core 15.

[0043] In this embodiment, the main stage also includes a valve sleeve 14, which is disposed on the main stage valve body. The valve sleeve 14 and the main stage valve body are symmetrically arranged with two inlet ports, two return ports, two control ports, and corresponding flow channels.

[0044] In this embodiment, the valve sleeve 14 is provided with a return oil throttling hole 7, which is located below the valve core 15 and serves as the bottom of the pre-stage flow field.

[0045] In this embodiment, the main stage also includes an oil filter 8, which is disposed in the control flow channel of the main stage valve body. The oil filter 8 has a fixed throttling orifice 16 at each end, and the two fixed throttling orifices 16 are respectively connected to two control flow channels inside the main stage valve body. The two control flow channels are connected to the ports at both ends of the valve core 15.

[0046] In this embodiment, the two nozzles 12 are symmetrically installed on both sides of the baffle 3 by press fitting. The two nozzles 12 and the planes on both sides of the baffle 3 form two variable throttling orifices, and the size of the variable throttling orifices is adjusted by deflecting the baffle 3.

[0047] In this embodiment, the pre-stage valve body is provided with two symmetrical nozzle chambers, which are symmetrically arranged on both sides of the baffle 3, and the two nozzles 12 are respectively arranged in one nozzle chamber.

[0048] In this embodiment, a plug 13 is provided at the end of the nozzle cavity away from the nozzle 12.

[0049] In this embodiment, the inner side of the bushing 4 near the baffle 3 is machined with rounded corners. The inner diameter of the bushing 4 is the same as the inner diameter of the main valve body, and the outer diameter of the bushing 4 is the same as the inner diameter of the pre-stage valve body. The bushing 4 is connected to the inside of the pre-stage valve body by press fitting.

[0050] In this embodiment, the bushing 4 is provided with a sealing ring 5 to seal between itself and the pre-stage valve body.

[0051] Furthermore, this embodiment also provides a method for using a mechanical feedback nozzle-baffle servo valve to suppress vortex shedding in the pre-stage, the specific steps of which are as follows:

[0052] When the servo valve is in the initial position, the coil 9 is not energized, the armature 10 is not under force, the baffle 3 is located in the middle of the left and right nozzles 12, the forces of the oil ejected from the left and right nozzles 12 on the baffle 3 cancel each other out, the baffle 3 does not deflect, the pressure loss generated by the variable throttling orifices on the left and right sides is the same, the control pressure at both ends of the main valve core 15 is also the same, the main valve core 15 is under balanced force, does not move, and has no load flow.

[0053] When the currents flowing through the left and right coils 9 are different, and the current in the left coil 9 is greater than that in the right coil 9, the electromagnetic torque generated by the left coil 9 is greater than that on the right. This causes the armature 10 to rotate clockwise, causing the baffle 3 to shift to the left. As a result, the distance between the baffle 3 and the two nozzles 12 is different. The variable throttle orifice on the left becomes smaller, and the variable throttle orifice on the right becomes larger. The hydraulic resistance of the two variable throttle orifices changes, resulting in a smaller pressure loss and higher pressure on the left and a larger pressure loss and lower pressure on the right. Consequently, the control pressure on the main valve core 15 on the left is less than that on the right, pushing the main valve core 15 to move to the right and driving the load to run. At the same time, the armature 10 deflects, causing the feedback rod 6 pressed on the armature 10 to also shift to the left, resulting in deformation and generating a counterclockwise feedback torque. Simultaneously, the movement of the valve core 15 causes the deformation of the feedback rod to increase, resulting in a correspondingly larger feedback torque. When the feedback torque generated by the two is superimposed and transmitted to the baffle 3, and is balanced with the electromagnetic torque generated by the torque motor, the valve core 15 is in the predetermined position, the baffle 3 is in the balanced state, and the required load flow and pressure are output, and the servo valve is in the predetermined working state.

[0054] This invention, through research, discovered that when the ratio of the width of the baffle 3 to the diameter of the pre-stage flow field at the bottom of the baffle 3 reaches a certain size, the larger the ratio, the less likely the pre-stage is to experience vortex street oscillations, until they cease altogether. When fluid flows in through the control channel and is injected into the pre-stage flow field from the nozzles 12 on both sides, it flows downwards along the baffle 3. Upon reaching the bottom of the baffle 3, separation vortices will form. However, due to the presence of the bushing 4, the diameter of the flow channel at the bottom of the baffle 3 decreases, and the effect of the bushing 4 wall on the fluid is enhanced, resulting in excessive fluid energy loss, weakened vortex effect, and reduced interaction between the separation vortices on both sides. Therefore, vortex streets cannot form, and the fluid flows directly downstream. Figure 2 As shown, this effectively suppresses the vortex oscillation phenomenon in the servo valve's pre-stage, reduces noise and vibration, and improves the service life of the electro-hydraulic servo valve.

[0055] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage, characterized in that, It includes a torque motor, a pre-stage and a main stage. The torque motor includes a magnetic conductor (1), a baffle (3), a feedback rod (6), a coil (9), an armature (10) and a permanent magnet (11). The pre-stage includes a pre-stage valve body, a bushing (4) and a nozzle (12). The main stage includes a main stage valve body and a valve core (15). The pre-stage valve body is provided with two vertically symmetrical magnetic conductors (1), an armature (10) is provided between the two magnetic conductors (1), a permanent magnet (11) is provided between the armature (10) and the magnetic conductors (1), and two sets of horizontally symmetrical coils (9) are provided between the permanent magnet (11) and the magnetic conductors (1). One end of the feedback rod (6) is connected to the middle of the armature (10), and the other end of the feedback rod (6) is connected to the valve core (15) in the main valve body. Baffles (3) are provided on both sides of the feedback rod (6), and bushings (4) are provided below the baffles (3). A nozzle (12) is provided at the end of the baffle (3) away from the feedback rod (6). The permanent magnet (11) is used to magnetize the upper and lower magnetic conductors (1) into N poles and S poles to form a fixed magnetic field. When the coil (9) is energized, the armature (10) will deflect in the counterclockwise or clockwise direction, thereby driving the baffle (3) to move. The inner side of the bushing (4) near the baffle (3) is machined with rounded corners. The inner diameter of the bushing (4) is consistent with the inner diameter of the main valve body. The outer diameter of the bushing (4) is consistent with the inner diameter of the pre-stage valve body. The bushing (4) is connected to the inside of the pre-stage valve body by press fitting.

2. The mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 1, characterized in that, The torque motor also includes a spring tube (2), the armature (10) is press-fitted together with the spring tube (2), the armature (10) is fixed above the pre-stage valve body through the spring tube (2), and the spring tube (2) is used to position the armature (10) in the middle of the symmetrical magnetic conductors (1).

3. The mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 2, characterized in that, The feedback rod (6) is pressed into the spring tube (2) by the baffle (3).

4. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 1, characterized in that, The main stage also includes a valve sleeve (14), which is disposed on the main stage valve body. The valve sleeve (14) and the main stage valve body are symmetrically arranged with two inlet ports, two return ports, two control ports and corresponding flow channels.

5. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 4, characterized in that, The valve sleeve (14) is provided with a return oil throttling hole (7), which is located below the valve core (15) and serves as the bottom of the pre-stage flow field.

6. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 4, characterized in that, The main stage also includes an oil filter (8), which is located in the control flow channel of the main stage valve body. The oil filter (8) has a fixed throttling orifice (16) at each end. The two fixed throttling orifices (16) are respectively connected to two control flow channels inside the main stage valve body. The two control flow channels are connected to the ports at both ends of the valve core (15).

7. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 1, characterized in that, The two nozzles (12) are symmetrically installed on both sides of the baffle (3) by press fitting. The two nozzles (12) and the planes on both sides of the baffle (3) form two variable throttling orifices, and the size of the variable throttling orifices is adjusted by deflecting the baffle (3).

8. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 1, characterized in that, The pre-stage valve body is provided with two symmetrical nozzle chambers, which are symmetrically arranged on both sides of the baffle (3), and the two nozzles (12) are respectively arranged in one nozzle chamber; a plug (13) is provided at the end of the nozzle chamber away from the nozzle (12).

9. A mechanical feedback nozzle-baffle servo valve for suppressing vortex shear in the pre-stage as described in claim 1, characterized in that, The bushing (4) is provided with a sealing ring (5) that seals with the pre-stage valve body.

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