High frequency pulsation filter type electro-hydraulic servo valve

Abstract

The present application belongs to the field of mechanical hydraulic pressure, and particularly relates to a high-frequency pulsation filtering type electro-hydraulic servo valve, which comprises a torque motor part, a hydraulic pressure amplification stage part, a power stage spool valve part, a turbine pressure compensation part, a pulsation filtering part and a shell; the torque motor part is installed on the upper side of the shell, and the hydraulic pressure amplification stage part, the power stage spool valve part, the turbine pressure compensation part and the pulsation filtering part are all installed in the shell; the present application can guarantee that the servo valve does not howl in all hydraulic systems, can slow down the internal pressure fluctuation of the servo valve, and thus effectively avoids high-frequency oscillation of the servo valve.

Description

Technical Field

[0001] The invention belongs to the field of mechanical hydraulics, and in particular relates to a high-frequency pulsation filtering type electro-hydraulic servo valve. Background Art

[0002] Currently, electro-hydraulic servovalves are widely used in advanced civil aircraft, steel, power generation and other important fields. They are mainly used in servo mechanism control systems. Their functions account for more than 1 / 3 of the system and strongly support the development of weapons. At present, the requirements for hydraulic servo systems are becoming increasingly higher, and the operating conditions are becoming more and more severe. If there are high-frequency pulsating components in the system or the external environment, the servo valve will be stimulated to resonate at high frequencies. When the frequency is high and the amplitude is large, the servo valve will scream, commonly known as howling within the industry. If the howling continues for a short time, the spring tube will fatigue and fracture, causing fatal failure to the hydraulic system. At present, the hydraulic system in the industry can specifically suppress the servo valve from howling in certain situations, but it cannot completely prevent the servo valve from howling in all hydraulic systems, which brings hidden dangers to the hydraulic system.

[0003] Relevant research shows that the high-frequency pulsation and howling of the servo valve are directly related to the transient cavitation formed at the nozzle-baffle. The cavitation causes the baffle to resonate, and the resonance of the baffle and the resonance of the valve core promote each other. Once the howling occurs, it will not stop actively. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of high-frequency pulsation and howling of the existing servo valve. The present invention proposes a high-frequency pulsation filter type electro-hydraulic servo valve.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-frequency pulsation filter type electro-hydraulic servo valve, comprising a torque motor, a hydraulic amplifier stage, a power stage slide valve, a turbine pressure compensation section, a pulsation filter section, and a housing; the torque motor is mounted on the upper side of the housing, and the hydraulic amplifier stage, the power stage slide valve, the turbine pressure compensation section, and the pulsation filter section are all mounted within the housing;

[0007] The torque motor is mounted on the housing and includes an upper magnet, a coil, a permanent magnet, an armature, a lower magnet, a spring tube, and a feedback rod. The permanent magnet is mounted between the upper and lower magnets, the coil is wound around the armature, the armature and the upper end of the feedback rod are mounted on the spring tube, and the lower end of the feedback rod is connected to the power valve core of the power stage slide valve.

[0008] The hydraulic amplification stage includes a left nozzle, a baffle, a right nozzle, a left throttle orifice component, an oil filter, and a right throttle orifice component. The left and right nozzles are symmetrically mounted on the housing, with the baffle positioned between the left and right nozzles. The left and right throttle orifice components are respectively sleeved on the left and right ends of the oil filter. The three components are collectively installed in the corresponding oil filter holes in the housing.

[0009] The power stage slide valve part includes a valve sleeve and a power valve core; the power valve core is installed in the valve sleeve and is installed in the valve sleeve hole of the housing together;

[0010] The turbine compensating pressure part includes a left turbine, a left bearing, a right bearing, and a right turbine. The left turbine is interference-mounted in the inner hole of the left bearing and is interference-mounted in the left hole of the baffle. The shaft of the right turbine is interference-mounted in the inner hole of the right bearing and is interference-mounted in the right hole of the baffle. The left turbine is coaxial with the left nozzle, and the right turbine is coaxial with the right nozzle.

[0011] The pulsation filter part includes a left filter upper spring, a left filter piston, a left filter lower spring, a right filter lower spring, a right filter piston, and a right filter upper spring; the left filter piston is slidably installed in the hole of the housing, the left filter upper spring is sleeved in the upper end cylinder of the left filter piston, the upper side presses on the inner wall of the housing hole, and the lower side presses on the shoulder end surface of the left filter piston; the left filter lower spring is sleeved in the lower end cylinder of the left filter piston, the lower side presses on the inner wall of the housing hole, and the upper side presses on the shoulder end surface of the left filter piston; the right filter piston is slidably installed in the hole of the housing, the right filter upper spring is sleeved in the upper end cylinder of the right filter piston, the upper side presses on the inner wall of the housing hole, and the lower side presses on the shoulder end surface of the right filter piston; the right filter lower spring is sleeved in the lower end cylinder of the right filter piston, the lower side presses on the inner wall of the housing hole, and the upper side presses on the shoulder end surface of the right filter piston;

[0012] The left end of the left nozzle, the left end of the left throttle component and the upper end of the left filter piston are connected through the housing oil channel; the right end of the right nozzle, the right end of the right throttle component and the upper end of the right filter piston are connected through the housing oil channel; the left end of the power valve core and the lower end of the left filter piston, and the right end of the power valve core and the lower end of the right filter piston (20) are respectively connected through the housing oil channel.

[0013] Furthermore, the oil passage of the housing Ps is connected to the oil passage where the oil filter is installed; the oil passages on the right side of the left nozzle and the left side of the right nozzle are both in communication with the cavity R.

[0014] Furthermore, the left turbine blade of the left turbine and the right turbine blade of the right turbine are symmetrical in curved surface, the flatness of the left turbine end face and the right turbine end face are both 0.002 mm, the diameter of the left turbine end face is 2 to 3 times the diameter of the left nozzle aperture, and the diameter of the right turbine end face is 2 to 3 times the diameter of the right nozzle aperture.

[0015] Furthermore, after the left turbine is installed on the baffle, the perpendicularity between the left turbine end face and the left nozzle hole axis is 0.005mm, and the coaxiality between the left turbine and the left nozzle hole axis is 0.02mm; after the right turbine is installed on the baffle, the perpendicularity between the right turbine end face and the right nozzle hole axis is 0.005mm, and the coaxiality between the right turbine and the right nozzle hole axis is 0.02mm.

[0016] Furthermore, the cylindrical diameters of the left filter piston and the right filter piston are no greater than 1 / 5 of the diameter of the power valve core.

[0017] Furthermore, the cylindricity of the left filter piston and the right filter piston cylinder is 0.001 mm, the surface roughness is Ra0.1, and the clearance between the cylinder and the hole of the housing is 0.005-0.010 mm.

[0018] Furthermore, the square root of the ratio of the combined stiffness of the left filter upper spring and the left filter lower spring to the weight of the left filter piston is equal to 0.6 to 0.8 times the system pulsation frequency; the square root of the ratio of the combined stiffness of the right filter upper spring and the right filter lower spring to the weight of the right filter piston is equal to 0.6 to 0.8 times the system pulsation frequency.

[0019] Furthermore, the shaft core diameter of the left turbine end face is smaller than 1 / 5 of the left nozzle aperture; the shaft core diameter of the right turbine end face is smaller than 1 / 5 of the right nozzle aperture.

[0020] Furthermore, the proportion of the solid part of the left turbine end surface on the circumference of the left nozzle outlet to the circumference of the left nozzle outlet is ≥60%, and the proportion of the solid part of the right turbine end surface on the circumference of the right nozzle outlet is ≥60%.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1) The main cause of nozzle-flapper servo valve whistling is the high hydraulic flow rate at the nozzle, which leads to negative pressure near the nozzle. Negative pressure vaporizes the hydraulic oil, which in turn generates cavitation. The generation and elimination of cavitation will produce high-frequency oscillations. Traditional servo valves cannot solve the cavitation problem near the nozzle. The patented invention invents a turbine pressure compensation mechanism. The faster the oil speed, the faster the turbine rotates, which can spread the pressurized oil to the periphery of the nozzle, quickly compensating for the negative pressure, avoiding the generation of cavitation, and thus avoiding high-frequency oscillation of the servo valve.

[0023] 2) Invented a spring-piston hydraulic filter, a simple, compact mechanism that effectively isolates the vibrations between components in a hydraulic system;

[0024] 3) The nozzle chamber and valve core of a traditional servo valve are directly connected by an oil channel. When the servo valve whistles, both the baffle and the valve core oscillate at high frequency. The baffle oscillation brings pressure fluctuations in the nozzle chamber, thereby promoting high-frequency oscillation of the valve core. The oscillation of the valve core then brings pressure fluctuations in the nozzle chamber. The baffle and the valve core promote each other's oscillations, and the oscillations cannot converge, resulting in continuous oscillation of the servo valve. The patent of this invention uses a spring-piston hydraulic filter for the servo valve. The pressure fluctuations caused by the oscillation of the baffle can be filtered, and the filtered pressure reduces the effect of the oscillation of the valve core; the pressure fluctuations caused by the high-frequency oscillation of the valve core can be filtered, and then the pressure fluctuations of the baffle are filtered, thereby reducing the fluctuations of the baffle. Furthermore, when there is high-frequency pulsation in the system pressure, the fluctuations of the baffle and the valve core reduce each other. This filter can reduce the pressure fluctuations inside the servo valve, thereby effectively avoiding high-frequency oscillations in the servo valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of a high-frequency pulsation filter type electro-hydraulic servo valve according to an embodiment of the present invention;

[0026] Figure 2 This is a structural diagram of a left turbine according to an embodiment of the present invention;

[0027] Figure 3 This is a structural diagram of the right turbine according to an embodiment of the present invention;

[0028] Figure 4 This is a structural diagram of a left nozzle according to an embodiment of the present invention;

[0029] Figure 5 This is a structural diagram of the right nozzle of an embodiment of the present invention;

[0030] Among them, 1. upper magnetic conductor, 2. coil, 3. permanent magnet, 4. armature, 5. lower magnetic conductor, 6. spring tube, 7. left nozzle, 8. baffle, 9. left turbine, 10. left bearing, 11. left throttle hole component, 12. oil filter, 13. left filter upper spring, 14. left filter piston, 15. left filter lower spring, 16. valve sleeve, 17. power valve core, 18. feedback lever, 19. right filter lower spring, 20. right filter piston, 21. right filter upper spring, 22. right throttle hole component, 23. right bearing, 24. right turbine, 25. right nozzle, 26. housing, 9A, left turbine blade, 9B, left turbine end face, 9C, left turbine end face diameter, 24A, right turbine blade, 24B, right turbine end face, 24C, right turbine end face diameter. DETAILED DESCRIPTION

[0031] In order to more intuitively and clearly describe the structural principles and working methods in the examples of the present invention, the embodiments will be introduced below in conjunction with relevant drawings. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] See attached Figure 1 The present invention provides a high-frequency pulsation filter type electro-hydraulic servo valve, which includes a torque motor part, a hydraulic amplifier part, a power stage slide valve part, a turbine pressure compensation part, a pulsation filter part, and a housing 26; the torque motor part is mounted on the upper side of the housing, and the hydraulic amplifier part, the power stage slide valve part, the turbine pressure compensation part, and the pulsation filter part are all mounted in the housing;

[0033] The torque motor is mounted on the housing 26 and includes an upper magnet 1, a coil 2, a permanent magnet 3, an armature 4, a lower magnet 5, a spring tube 6, and a feedback rod 18. The permanent magnet 3 is disposed between the upper magnet 1 and the lower magnet 5. The coil 2 is wound around the armature 4. The armature 4 and the upper end of the feedback rod 18 are mounted on the spring tube 6. The lower end of the feedback rod is connected to the power valve core 17 of the power stage slide valve.

[0034] The hydraulic amplification stage includes a left nozzle 7, a baffle 8, a right nozzle 25, a left throttle component 11, an oil filter 12, and a right throttle component 22. The left nozzle 7 and the right nozzle 25 are symmetrically mounted on the housing, with the baffle 8 positioned between the left and right nozzles 7 and 25. The left throttle component 11 and the right throttle component 22 are respectively mounted on the left and right ends of the oil filter 12. The three components are collectively mounted in the corresponding oil filter holes of the housing 26.

[0035] The power stage slide valve portion includes a valve sleeve 16 and a power valve core 17; the power valve core 17 is installed in the valve sleeve 16 and together is installed in the valve sleeve hole of the housing 26;

[0036] The turbine booster section includes a left turbine 9, a left bearing 10, a right bearing 23, a right turbine 24, and a baffle 8. The left turbine 9 is interference-fitted into the inner hole of the left bearing 10, and both are interference-fitted into the left hole of the baffle 8. The shaft of the right turbine 24 is interference-fitted into the inner hole of the right bearing 23, and both are interference-fitted into the right hole of the baffle 8. The left turbine 9 is coaxial with the left nozzle 7, and the right turbine 24 is coaxial with the right nozzle 25.

[0037] The pulsation filter part includes the left filter upper spring 13, the left filter piston 14, the left filter lower spring 15, the right filter lower spring 19, the right filter piston 20, and the right filter upper spring 21;

[0038] The left filter piston 14 is slidably mounted in the hole of the housing 26. The left filter upper spring 13 is sleeved in the upper end cylinder of the left filter piston 14, with the upper side pressing against the housing and the lower side pressing against the shoulder end surface of the left filter piston 14. The left filter lower spring 15 is sleeved in the lower end cylinder of the left filter piston 14, with the lower side pressing against the housing and the upper side pressing against the shoulder end surface of the left filter piston 14.

[0039] The right filter piston 20 is slidably installed in the hole of the housing 26. The right filter upper spring 21 is sleeved in the upper end cylinder of the right filter piston 20, with the upper side pressing against the housing and the lower side pressing against the shoulder end surface of the right filter piston 20. The right filter lower spring 19 is sleeved in the lower end cylinder of the right filter piston 20, with the lower side pressing against the housing and the upper side pressing against the shoulder end surface of the right filter piston 20.

[0040] The left end of the left nozzle 7 and the left end of the left throttle component 11 are connected to the upper end of the left filter piston 14 through the oil passage of the housing 26; the right end of the right nozzle 25 and the right end of the right throttle component 22 are connected to the upper end of the right filter piston 20 through the oil passage of the housing 26;

[0041] The left end of the power valve core 17 is connected to the lower end of the left filter piston 14, and the right end of the power valve core 17 is connected to the lower end of the right filter piston 20 through the oil passage of the housing 26;

[0042] The oil passage of the housing 26Ps is connected to the oil passage where the oil filter 12 is installed; the right side of the left nozzle 7 and the left side of the right nozzle 25 are in communication with the cavity R.

[0043] In the present invention, the left turbine blade 9A and the right turbine blade 24A are symmetrical in curved surface, ensuring that when the left nozzle 7 and the right nozzle 25 eject oil at high speed, the left turbine 9 and the right turbine 24 rotate in the same direction, which is conducive to the left and right turbines compensating for the air pockets near the baffle.

[0044] The flatness of the left turbine end face 9B and the right turbine end face 24B are both 0.002mm. The high-precision flatness can ensure the balance of hydraulic pressure between the internal blades of the left turbine 9 and the right turbine 24, avoiding the shock caused by the hydraulic force.

[0045] The left turbine end face diameter 9C is 2 to 3 times the diameter of the left nozzle 7, and the right turbine end face diameter 24C is 2 to 3 times the diameter of the right nozzle 25. This allows the jets from the left nozzle 7 and the right nozzle 25 to fully act on the left turbine end face 9B and the right turbine end face 24B, allowing the baffle to effectively adjust the pressure gain and flow gain of the hydraulic amplifier stage, improving work efficiency.

[0046] In the present invention, after the left turbine 9 is mounted on the baffle 8, the perpendicularity between the left turbine end face 9B and the axis of the left nozzle 7 hole is 0.005mm, and the coaxiality between the left turbine 9 and the axis of the left nozzle 7 hole is 0.02mm. After the right turbine 24 is mounted on the baffle 8, the perpendicularity between the right turbine end face 24B and the axis of the right nozzle 25 hole is 0.005mm, and the coaxiality between the right turbine 24 and the axis of the right nozzle 25 hole is 0.02mm. This ensures that the hydraulic forces acting on the left turbine blades 9A and the right turbine blades 24A are balanced, and the eccentric forces of the left turbine 9 and the right turbine 24 are minimal, resulting in smooth movement of the left turbine 9 and the right turbine 24.

[0047] In the present invention, the cylindrical diameter of the left and right filter pistons 14, 20 is no greater than one-fifth the diameter of the power valve core 17. The flow rate required for the movement of the left and right filter pistons 14, 20 is very small, ensuring that the hydraulic pressure at the upper ends of the left and right filter pistons 14, 20 is quickly transmitted to the two end surfaces of the power valve core 17 without affecting the response frequency of the power valve core 17. Consequently, the configuration of the left and right filter pistons 14, 20 does not affect the normal bandwidth of the servo valve.

[0048] In the present invention, the cylindrical cylindricity of the left filter piston 14 and the right filter piston 20 is 0.001mm, the surface roughness is Ra0.1, and the clearance with the housing hole is 0.005-0.010mm. This ensures that the left filter piston 14 and the right filter piston 20 can move smoothly in the housing hole 26, and has good wear resistance and long service life.

[0049] In the present invention, the square root of the ratio of the combined stiffness of the left filter upper spring 13 and the left filter lower spring 15 to the weight of the left filter piston 14 is equal to 0.6 to 0.8 times the system pulsation frequency; and the square root of the ratio of the combined stiffness of the right filter upper spring 21 and the right filter lower spring 19 to the weight of the right filter piston 20 is equal to 0.6 to 0.8 times the system pulsation frequency. This ensures that the pulsation filtering mechanism effectively attenuates the amplitude at the system pulsation frequency, thereby significantly reducing the amplitude of the resonant pulsation and the energy of the pulsation, thereby improving the stability of the servo valve.

[0050] In the present invention, the left turbine end face axial core diameter 9D is less than 1 / 5 of the aperture of the left nozzle 7; and the right turbine end face axial core diameter 24D is less than 1 / 5 of the aperture of the right nozzle 25. This ensures that the jets from the left nozzle 7 and the right nozzle 25 act on a larger area of ​​the left turbine blade 9A and the right turbine blade (24A), allowing the left turbine 9 and the right turbine 24 to have a higher rotation speed and better compensate for cavitation near the baffle.

[0051] In the present invention, the substantial portion of the left turbine end surface 9B on the circumference of the left nozzle 7 outlet accounts for ≥60% of the circumference of the left nozzle 7 outlet, and the substantial portion of the right turbine end surface 24B on the circumference of the right nozzle 25 outlet accounts for ≥60% of the circumference of the right nozzle 25 outlet. This allows the jets from the left nozzle 7 and the right nozzle 25 to act on both the left turbine end surface 9B and the right turbine end surface 24B, ensuring sufficient jet area for both surfaces. This allows the baffle to effectively adjust the pressure gain and flow gain of the hydraulic amplifier stage, thereby improving operating efficiency.

[0052] The working principle of the high-frequency pulsation filter type electro-hydraulic servo valve of the present invention is as follows: the hydraulic pump servo valve inputs the oil supply pressure Ps. When the coil 2 inputs a positive current, the armature 4 is affected by the electromagnetic force and moves counterclockwise around the rotation center of the spring tube 6, driving the baffle 8 and the left and right turbine pressure-compensating parts to deflect to the right, thereby reducing the pressure on the left side of the left nozzle 7 and increasing the pressure on the right side of the right nozzle 25. The left and right pulsation filter parts respectively transmit the corresponding pressure downward to the power valve core 17, and the power valve core 17 moves to the left. The high-pressure oil outputs pressure and flow through the opening of the power valve core 17 and the valve sleeve 16. In addition, the displacement of the power valve core 17 transmits the force to the spring tube 6 through the feedback rod 18, and finally achieves force balance, and the valve core stops at the specified position. Similarly, when the coil 2 inputs a negative current, the movement direction of the internal parts of the servo valve is opposite to that described above. This servo valve also includes a turbine pressure-compensating part and a pulsation filter part, and its working process is as follows:

[0053] Turbine pressure compensation: The high hydraulic flow rate at the outlet of the left nozzle 7 and the right nozzle 25 causes negative pressure near the nozzle. This negative pressure vaporizes the hydraulic oil, which in turn creates cavitation. The generation and elimination of cavitation produces high-frequency oscillations. A turbine pressure compensation mechanism is installed at the nozzle. The faster the oil flow rate, the faster the turbine rotates, which can spread the pressurized oil to the periphery of the nozzle, quickly compensating for the negative pressure, avoiding the generation of cavitation, and thus preventing high-frequency oscillation of the servo valve.

[0054] Pulsation filtering: A spring-piston hydraulic filter is placed between the two nozzles and the power valve core 17. This filters pressure fluctuations caused by flapper oscillation, which in turn mitigates the effect of the filtered pressure on the valve core oscillation. High-frequency pressure fluctuations from the valve core are also filtered, which in turn filters pressure fluctuations from the flapper, thereby mitigating flapper fluctuations. Furthermore, when high-frequency system pressure pulsates, the flapper and valve core mutually mitigate fluctuations. This filter reduces pressure fluctuations within the servo valve, effectively preventing high-frequency oscillations.

[0055] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. A high-frequency pulsation filter type electro-hydraulic servo valve, characterized in that: It includes a torque motor part, a hydraulic amplifier stage part, a power stage slide valve part, a turbine pressure compensation part, a pulsation filter part and a housing; the torque motor part is installed on the upper side of the housing, and the hydraulic amplifier stage part, the power stage slide valve part, the turbine pressure compensation part and the pulsation filter part are all installed in the housing; The torque motor part includes an upper magnet, a coil, a permanent magnet, an armature, a lower magnet, a spring tube, and a feedback rod. The permanent magnet is arranged between the upper and lower magnets, the coil is wound around the armature, the armature and the upper end of the feedback rod are mounted on the spring tube, and the lower end of the feedback rod is connected to the power valve core of the power stage slide valve part. The hydraulic amplification stage includes a left nozzle, a baffle, a right nozzle, a left throttle orifice component, an oil filter, and a right throttle orifice component. The left and right nozzles are symmetrically mounted on the housing, with the baffle positioned between the left and right nozzles. The left and right throttle orifice components are respectively sleeved on the left and right ends of the oil filter. The three components are collectively installed in the corresponding oil filter holes in the housing. The power stage slide valve part includes a valve sleeve and a power valve core; the power valve core is installed in the valve sleeve and is installed in the valve sleeve hole of the housing together; The turbine compensating pressure part includes a left turbine, a left bearing, a right bearing, and a right turbine. The left turbine is interference-mounted in the inner hole of the left bearing and is interference-mounted in the left hole of the baffle. The shaft of the right turbine is interference-mounted in the inner hole of the right bearing and is interference-mounted in the right hole of the baffle. The left turbine is coaxial with the left nozzle, and the right turbine is coaxial with the right nozzle. The pulsation filter part includes a left filter upper spring, a left filter piston, a left filter lower spring, a right filter lower spring, a right filter piston, and a right filter upper spring; the left filter piston is slidably installed in the hole of the housing, the left filter upper spring is sleeved in the upper end cylinder of the left filter piston, the upper side presses on the inner wall of the housing hole, and the lower side presses on the shoulder end surface of the left filter piston; the left filter lower spring is sleeved in the lower end cylinder of the left filter piston, the lower side presses on the inner wall of the housing hole, and the upper side presses on the shoulder end surface of the left filter piston; the right filter piston is slidably installed in the hole of the housing, the right filter upper spring is sleeved in the upper end cylinder of the right filter piston, the upper side presses on the inner wall of the housing hole, and the lower side presses on the shoulder end surface of the right filter piston; the right filter lower spring is sleeved in the lower end cylinder of the right filter piston, the lower side presses on the inner wall of the housing hole, and the upper side presses on the shoulder end surface of the right filter piston; The left end of the left nozzle, the left end of the left throttle component and the upper end of the left filter piston are connected through the housing oil channel; the right end of the right nozzle, the right end of the right throttle component and the upper end of the right filter piston are connected through the housing oil channel; the left end of the power valve core and the lower end of the left filter piston, and the right end of the power valve core and the lower end of the right filter piston (20) are respectively connected through the housing oil channel.

2. A high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The oil passage of the housing Ps is connected to the oil passage where the oil filter is installed; the oil passages on the right side of the left nozzle and on the left side of the right nozzle are both in communication with the cavity R.

3. A high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The left turbine blade of the left turbine and the right turbine blade of the right turbine are symmetrical in surface, the flatness of the left turbine end face and the right turbine end face are both 0.002mm, the diameter of the left turbine end face is 2 to 3 times the diameter of the left nozzle aperture, and the diameter of the right turbine end face is 2 to 3 times the diameter of the right nozzle aperture.

4. A high-frequency pulsation filter type electro-hydraulic servo valve as claimed in claim 3, characterized in that: After the left turbine is installed on the baffle, the perpendicularity between the left turbine end face and the left nozzle hole axis is 0.005mm, and the coaxiality between the left turbine and the left nozzle hole axis is 0.02mm; after the right turbine is installed on the baffle, the perpendicularity between the right turbine end face and the right nozzle hole axis is 0.005mm, and the coaxiality between the right turbine and the right nozzle hole axis is 0.02mm.

5. The high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The cylindrical diameters of the left filter piston and the right filter piston are no greater than 1 / 5 of the diameter of the power valve core.

6. A high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The cylindricity of the left filter piston and the right filter piston cylinder is 0.001 mm, the surface roughness is Ra0.1, and the matching clearance with the hole of the housing is 0.005-0.010 mm.

7. The high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The square root of the ratio of the combined stiffness of the left filter upper spring and the left filter lower spring to the weight of the left filter piston is equal to 0.6 to 0.8 times the system pulsation frequency; the square root of the ratio of the combined stiffness of the right filter upper spring and the right filter lower spring to the weight of the right filter piston is equal to 0.6 to 0.8 times the system pulsation frequency.

8. The high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The shaft core diameter of the left turbine end face is smaller than 1 / 5 of the left nozzle aperture; the shaft core diameter of the right turbine end face is smaller than 1 / 5 of the right nozzle aperture.

9. The high-frequency pulsation filter type electro-hydraulic servo valve according to claim 1, characterized in that: The proportion of the solid part of the left turbine end face on the circumference of the left nozzle outlet to the circumference of the left nozzle outlet is greater than or equal to 60%, and the proportion of the solid part of the right turbine end face on the circumference of the right nozzle outlet is greater than or equal to 60%.

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