Mechanical feedback type nozzle-baffle servo valve for restraining prestage vortex street oscillation

Abstract

The invention relates to a mechanical feedback type nozzle-baffle servo valve for inhibiting pre-stage vortex street oscillation, which comprises a torque motor, a pre-stage and a main stage, the torque motor comprises a magnetizer, a baffle, a feedback rod, a coil, an armature and a permanent magnet, the pre-stage comprises a pre-stage valve body, a bushing and a nozzle, and the main stage comprises a main stage valve body and a valve core. Compared with the prior art, the mechanical feedback type nozzle-baffle servo valve for restraining prestage vortex street oscillation is designed from the vortex street oscillation phenomenon of a baffle wake flow area according to the relation between the vortex street oscillation frequency and the width of a flow field, and a lining structure is additionally arranged in the prestage baffle wake flow area of the servo valve; the flow field width of a drainage basin at the bottom of the baffle is limited, the prestage vortex street oscillation phenomenon of the servo valve can be effectively restrained, noise vibration is reduced, and the service life of the electro-hydraulic servo valve is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic control valves, and in particular to a mechanical feedback nozzle-flapper servo valve for suppressing vortex street oscillation of a pre-stage. Background Art

[0002] The electro-hydraulic servo valve is one of the key components that affect the performance of the hydraulic servo system. It is used to connect the electrical and hydraulic parts of the system to achieve the functions of electro-hydraulic conversion and power amplification. Among them, the research on the nozzle-flapper servo valve started earlier. It has fast dynamic response speed, high sensitivity, good linearity, and small temperature and pressure zero drift. It is widely used in CNC machine tools, locomotives, ships, radars, flight devices and other automatic control equipment that require high-precision control. In order to meet the application requirements, the size of the nozzle-flapper servo valve is getting smaller and smaller, the core speed of the pre-stage jet is getting larger and larger, and the high-speed jet is ejected from the nozzle flow. Most of the fluid will flow along the baffle to the wake area and separate at the tail of the baffle to form two rows of vortices. As the Reynolds number of the fluid increases, periodic alternating vortices will be formed on both sides of the baffle, generating flow field pressure pulsation, causing the servo valve pre-stage self-oscillation. The servo valve pre-stage self-oscillation will form high-frequency noise, and due to the alternating stress generated by the oscillation, the spring tube may suffer fatigue fracture, resulting in the failure of the servo valve.

[0003] In order to suppress the self-oscillation phenomenon of the pre-stage of the nozzle-baffle servo valve, Chinese patent CN 206929154 U discloses a servo valve self-oscillation suppression device with an adjustable nozzle baffle distance; Chinese patent CN 207961119 U discloses a nozzle baffle servo valve for suppressing pre-stage cavitation; Chinese patent CN 114893474 B discloses a method for suppressing the self-oscillation of a double nozzle baffle servo valve; the above patents all suppress the oscillation phenomenon of the local flow field between the nozzle and the baffle through structural innovation, but cannot satisfy the suppression of the vortex street oscillation phenomenon in the baffle wake area. Summary of the invention

[0004] The purpose of the present invention is to suppress the problem of damage to the armature assembly caused by vortex oscillation of the pre-stage vortex street of the injection servo valve in the prior art and to provide a mechanical feedback nozzle-baffle servo valve that suppresses the vortex street oscillation of the pre-stage, so as to effectively suppress the vortex street oscillation phenomenon of the pre-stage of the servo valve, reduce noise and vibration, and increase service life.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A mechanical feedback nozzle-flapper servo valve for suppressing vortex street oscillation of a pre-stage comprises a torque motor, a pre-stage and a main stage, wherein the torque motor comprises a magnetic conductor, a baffle, a feedback rod, a coil, an armature and a permanent magnet, the pre-stage comprises a pre-stage valve body, a bushing and a nozzle, and the main stage comprises a main stage valve body and a valve core;

[0007] Two vertically symmetrical magnetic conductors are arranged above the pre-stage valve body, an armature is arranged between the two magnetic conductors, a permanent magnet is arranged between the armature and the magnetic conductor, and two groups of left-right symmetrical coils are arranged between the permanent magnet and the magnetic conductor;

[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 under the baffles. A nozzle is provided at one 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 to form a fixed magnetic field. When the coil is energized, the armature will deflect in the counterclockwise or clockwise direction, thereby driving the baffle to move.

[0010] Furthermore, the torque motor also includes a spring tube, the armature and the spring tube are pressed together, the armature is fixed above the pre-stage valve body through the spring tube, and the spring tube is used to make the armature located in the middle of the upper and lower symmetrical magnetic conductors.

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

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

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

[0014] Furthermore, the main stage further comprises a valve sleeve, which is arranged on the main stage valve body, and the valve sleeve and the main stage valve body are symmetrically provided with two inlet ports, two oil return ports, two control flow ports and corresponding flow channels.

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

[0016] Furthermore, the main stage also includes an oil filter, which is arranged in the control flow channel of the main stage valve body. A fixed throttling hole is respectively provided at both ends of the oil filter, and the two fixed throttling holes are respectively connected to the two control flow channels inside the main stage valve body, and 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, and the two nozzles and the planes on both sides of the baffle form two variable throttling holes, and the size of the variable throttling holes is adjusted by deflecting the baffle.

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

[0019] Furthermore, in the above, a plug is provided at one end of the nozzle chamber away from the nozzle.

[0020] Furthermore, the inner side of the bushing near the baffle is processed into a rounded corner, the inner diameter of the bushing is consistent with the inner diameter of the main stage 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 pre-stage valve body by press fitting.

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

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

[0023] The pressure on both ends of the main stage valve core of the present invention depends on the control pressure difference between the control flow channel and the chambers on both sides of the main stage valve core. The control pressure in the control flow channels on both sides depends on the size of the variable throttle hole formed between the nozzle and the baffle. The different sizes of the variable throttle holes on the left and right sides will produce different pressure losses, so that a pressure difference is generated on the left and right sides of the main stage valve core, which drives the movement of the main stage valve core.

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

[0025] Starting from the vortex street oscillation phenomenon in the baffle wake zone, the present invention designs a mechanical feedback nozzle-baffle servo valve for suppressing the pre-stage vortex street oscillation according to the relationship between the vortex street oscillation frequency and the width of the flow field. A bushing structure is added to the pre-stage baffle wake zone of the servo valve to limit the flow field width of the baffle bottom flow domain, which can effectively suppress the pre-stage vortex street oscillation phenomenon of the servo valve, reduce noise and vibration, and increase the service life of the electro-hydraulic servo valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the mechanical feedback nozzle-flapper servo valve in the present invention;

[0027] Figure 2 It is a simulation verification speed cloud diagram of the present invention.

[0028] Explanation of the accompanying figures: 1. magnetic conductor, 2. spring tube, 3. baffle, 4. bushing, 5. sealing ring, 6. feedback rod, 7. oil return throttle hole, 8. oil filter, 9. coil, 10. armature, 11. permanent magnet, 12. nozzle, 13. plug, 14. valve sleeve, 15. valve core, 16. fixed throttle hole. DETAILED DESCRIPTION

[0029] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In conjunction with the accompanying drawings, some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0034] Example 1

[0035] See also Figure 1The present embodiment provides a mechanical feedback nozzle-flapper servo valve for suppressing vortex street oscillation of a pre-stage, a mechanical feedback nozzle-flapper servo valve for suppressing vortex street oscillation of a pre-stage, comprising a torque motor, a pre-stage and a main stage, the torque motor comprising 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 comprising a pre-stage valve body, a bushing 4 and a nozzle 12, the main stage comprising a main stage valve body and a valve core 15;

[0036] Two vertically symmetrical magnets 1 are arranged above the pre-stage valve body, an armature 10 is arranged between the two magnets 1, a permanent magnet 11 is arranged between the armature 10 and the magnets 1, and two groups of left-right symmetrical coils 9 are arranged between the permanent magnet 11 and the magnets 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. The end of the baffle 3 away from the feedback rod 6 is provided with a nozzle 12;

[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 counterclockwise or clockwise, thereby driving the baffle 3 to move.

[0039] In this embodiment, the torque motor further includes a spring tube 2, the armature 10 is pressed 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 make the armature 10 located in the middle of the upper and lower symmetrical magnetic conductor 1.

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

[0041] In this embodiment, the feedback rod 6 is press-fitted into the spring tube 2 through the baffle 3 .

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

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

[0044] In this embodiment, an oil return throttling hole 7 is provided on the valve sleeve 14. The oil return throttling hole 7 is located below the valve core 15. The oil return throttling hole 7 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 arranged in the control flow channel of the main stage valve body. A fixed throttling hole 16 is provided at both ends of the oil filter 8. The two fixed throttling holes 16 are respectively connected to the two control flow channels inside the main stage valve body, and 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 holes, and the size of the variable throttling holes is adjusted by deflecting the baffle 3.

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

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

[0049] In this embodiment, the inner side of the bushing 4 near the baffle 3 is processed into a rounded corner, the inner diameter of the bushing 4 is consistent with the inner diameter of the main stage valve body, the outer diameter of the bushing 4 is consistent with the inner diameter of the pre-stage valve body, and the bushing 4 is connected to the inside of the pre-stage valve body by pressing.

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

[0051] In addition, this embodiment also provides a method for using a mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation, and the specific steps are as follows:

[0052] When the servo valve is in the initial position, the coil 9 is not energized, the armature 10 is not subjected to 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 acting on the baffle 3 cancel each other out, the baffle 3 does not deflect, the pressure losses caused by the variable throttle holes on the left and right sides are the same, the control pressures at both ends of the main-stage valve core 15 are also the same, the main-stage valve core 15 is under balanced force, does not move, and has no load flow.

[0053] When the currents passing through the left and right coils 9 are different, when the current of the left coil 9 is greater than that of the right coil 9, the electromagnetic torque generated by the left coil 9 is greater than that of the right, causing the armature 10 to rotate clockwise and the baffle 3 to shift to the left, so that the distances between the baffle 3 and the two nozzles 12 are different, the left variable throttle hole becomes smaller, and the right variable throttle hole becomes larger, and the liquid resistance of the two variable throttle holes changes, so that the pressure loss on the left is small and the pressure is large, and the pressure loss on the right is large and the pressure is small, so that the control pressure on the left side of the main-stage valve core 15 is smaller than the control pressure on the right side, pushing the main-stage valve core 15 to move rightward, driving the load to operate, and at the same time, the armature 10 deflects, driving the feedback rod 6 pressed on the armature 10 to shift to the left, deform, and generate a counterclockwise feedback torque. At the same time, the movement of the valve core 15 causes the feedback rod to deform larger, and the feedback torque is correspondingly larger. When the feedback torque generated by the two is superimposed and transmitted to the baffle 3, and balanced with the electromagnetic torque generated by the torque motor, the valve core 15 is in a predetermined position, and the baffle 3 is in a balanced state. At this time, the required load flow and pressure are output, and the servo valve is in a predetermined working state.

[0054] Through research, the present invention has found 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 will have vortex street oscillation, until it no longer occurs. When the fluid flows in through the control flow channel and is injected into the pre-stage flow field from the nozzles 12 on both sides, it will flow downward along the baffle 3. When it flows to the bottom of the baffle 3, a separation flow will occur to form a separation vortex. However, due to the presence of the bushing 4, the diameter of the flow channel at the bottom of the baffle 3 is reduced, and the effect of the bushing 4 wall on the fluid is enhanced, resulting in excessive fluid energy loss, weakened vortex effect, and weakened interaction between the separation vortices on both sides. A vortex street cannot be formed, and it flows directly downstream, such as Figure 2 As shown, the vortex street oscillation phenomenon of the pre-stage of the servo valve is effectively suppressed, the noise and vibration are reduced, and the service life of the electro-hydraulic servo valve is prolonged.

[0055] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and 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 present invention should be within the scope of protection of the present invention.

Claims

1. A mechanical feedback nozzle-flapper servo valve for suppressing vortex oscillation of the pre-stage, characterized in that: The invention comprises a torque motor, a pre-stage and a main stage, wherein the torque motor comprises 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 comprises a pre-stage valve body, a bushing (4) and a nozzle (12), and the main stage comprises a main stage valve body and a valve core (15); Two vertically symmetrical magnetic conductors (1) are arranged above the pre-stage valve body, an armature (10) is arranged between the two magnetic conductors (1), a permanent magnet (11) is arranged between the armature (10) and the magnetic conductor (1), and two groups of left-right symmetrical coils (9) are arranged between the permanent magnet (11) and the magnetic conductor (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), a bushing (4) is provided below the baffle (3), and a nozzle (12) is provided at one 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.

2. A mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 1, characterized in that: The torque motor further comprises a spring tube (2), the armature (10) and the spring tube (2) are pressed together, the armature (10) is fixed above the pre-stage valve body through the spring tube (2), and the spring tube (2) is used to make the armature (10) located in the middle of the upper and lower symmetrical magnetic conductor (1).

3. A mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 2, characterized in that: The feedback rod (6) is pressed into the interior of the spring tube (2) through a baffle (3).

4. A mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 1, characterized in that: The main stage further comprises a valve sleeve (14), wherein the valve sleeve (14) is arranged on the main stage valve body, and the valve sleeve (14) and the main stage valve body are symmetrically provided with two inlet ports, two oil return ports, two control flow ports and corresponding flow channels.

5. A mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 4, characterized in that: An oil return throttling hole (7) is provided on the valve sleeve (14), and the oil return throttling hole (7) is located below the valve core (15). The oil return throttling hole (7) serves as the bottom of the pre-stage flow field.

6. A mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 4, characterized in that: The main stage further comprises an oil filter (8), the oil filter (8) being arranged in the control flow passage of the main stage valve body, and a fixed throttle hole (16) being respectively arranged at both ends of the oil filter (8), the two fixed throttle holes (16) being respectively connected to the two control flow passages inside the main stage valve body, and the two control flow passages being in communication with ports at both ends of the valve core (15).

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

8. The mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 1, characterized in that: The pre-stage valve body is provided with two symmetrical nozzle cavities, the two nozzle cavities are symmetrically arranged on both sides of the baffle (3), and the two nozzles (12) are respectively arranged in one nozzle cavity; a plug (13) is provided at one end of the nozzle cavity away from the nozzle (12).

9. The mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 1, characterized in that: The inner side of the bushing (4) near the baffle (3) is processed into a rounded corner, the inner diameter of the bushing (4) is consistent with the inner diameter of the main stage valve body, the outer diameter of the bushing (4) is consistent with the inner diameter of the pre-stage valve body, and the bushing (4) is connected to the pre-stage valve body by press-fitting.

10. The mechanical feedback nozzle-flapper servo valve for suppressing pre-stage vortex oscillation according to claim 1, characterized in that: The outside of the bushing (4) is provided with a sealing ring (5) for sealing with the pre-stage valve body.

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