A low noise electro-hydraulic servo valve

Abstract

The present application belongs to the field of mechanical hydraulic pressure, and particularly relates to a low-noise electro-hydraulic servo valve, which comprises a torque motor part arranged on a shell, and a hydraulic pressure amplification stage part, a power stage spool valve part, a wave absorbing device and an air pocket oil supplementing part arranged in the shell; the wave absorbing device of the present application can filter hydraulic pressure pulsation in the bladder, and the different lengths and diameters of the capillary pipes can offset the wave crest and trough of the hydraulic oil pressure pulsation of the output capillary pipe, thereby reducing the fluctuation of the oil supply pressure. The present application innovatively solves the problem of oil supply pressure fluctuation filtering, and the air pocket oil supplementing device of the present application can quickly capture air pockets and rapidly supplement them with high-pressure oil, greatly shortening the air pocket existence time and avoiding the difficult-to-implement measures such as complex structure design, strong sealing and corrosion-resistant materials taken in traditional hydraulic pressure to reduce air pockets.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical hydraulic pressure, and particularly relates to a low-noise electro-hydraulic servo valve. BACKGROUND

[0002] At present, the electro-hydraulic servo valve is widely applied in important fields such as advanced civil aircraft, steel and power generation, and is mainly applied in servo mechanism control systems, and the function accounts for more than 1 / 3 of the system, and strongly supports the development of weapons. At present, the hydraulic servo system requires higher and higher, and the working condition is more and more severe. If there is a high-frequency pulsation component in the system or the external environment, the servo valve will be excited to high-frequency resonance, and when the frequency is high and the amplitude is large, the servo valve will emit a scream, which is commonly known as howling in the industry. The spring tube will fatigue and break within a very short time of howling, causing fatal failure to the hydraulic system. At present, the hydraulic system in the industry can specifically inhibit the howling of the servo valve in some occasions, but cannot completely achieve the howling of the servo valve in all hydraulic systems, which brings hidden troubles to the hydraulic system.

[0003] Relevant research shows that the high-frequency pulsation and howling of the servo valve is directly related to the transient gas cavity formed at the nozzle-damper, the gas cavity causes the damper to resonate, and the resonance of the damper and the resonance of the valve core promote each other, and then once howling, it will not stop voluntarily. SUMMARY

[0004] The technical problem solved by the present application: in order to solve the shortcomings of the existing servo valve high-frequency pulsation and howling, the present application provides a low-noise electro-hydraulic servo valve.

[0005] Technical scheme of the present application

[0006] A low-noise electro-hydraulic servo valve, comprising a torque motor part arranged on a shell, and a hydraulic amplification stage part, a power stage spool part, a wave suppression device, a gas cavity oil supplement part arranged in the shell;

[0007] The torque motor part comprises an upper magnetic conductor, a coil, a permanent magnet, an armature, a lower magnetic conductor, a spring tube and a feedback rod, the permanent magnet is arranged between the upper magnetic conductor and the lower magnetic conductor, the coil is wound on the armature, the upper end of the armature and the feedback rod is installed on the spring tube, and the lower end of the feedback rod is connected with a power valve core of the power stage spool part;

[0008] The hydraulic amplification stage part comprises a left nozzle, a damper, a right nozzle, a left throttle hole part, an oil filter and a right throttle hole part, the left nozzle and the right nozzle are symmetrically arranged in the shell, the damper is arranged between the left nozzle and the right nozzle, the left throttle hole part and the right throttle hole part are respectively sleeved on the left and right ends of the oil filter, and the three parts are jointly arranged in the corresponding oil filter hole of the shell; the left end of the left nozzle and the left end of the left throttle hole part are connected with the left end of the power valve core through the shell oil channel; the right end of the right nozzle and the right end of the right throttle hole part are connected with the right end of the power valve core through the shell oil channel;

[0009] The power stage spool part comprises a valve sleeve and a power spool; the power spool is installed in the valve sleeve, and both are installed in the valve sleeve hole of the housing;

[0010] The wave breaking device comprises an oil inlet hole component, a bladder, an oil outlet hole component, a connecting plate, and capillary pipes; the lower end of the oil inlet hole component is connected with the housing and communicates with the oil inlet cavity Ps; the upper end of the oil inlet hole component is connected with the bladder; the upper end of the bladder is connected with the oil outlet hole component; the upper end of the oil outlet hole component is connected with the connecting plate; the upper end of the connecting plate is connected with a plurality of capillary pipes with different lengths and diameters.

[0011] The air pocket oil supplementing part comprises a left air pocket collecting nozzle, a left spring, a left oil supplementing spool, a left oil supplementing nozzle, a right oil supplementing nozzle, a right oil supplementing spool, a right spring, and a right air pocket collecting nozzle; the left oil supplementing spool is slidably installed in the left hole of the housing; the left spring is sleeved in the right end cylinder of the left oil supplementing spool; the right side of the left spring is abutted against the left air pocket collecting nozzle fixed in the left hole; the left air pocket collecting nozzle is a through structure; the left side of the left spring is abutted against the right end surface of the right shoulder of the left oil supplementing spool; the left end of the left oil supplementing spool is connected with the overflow cavity through an oil channel; the right end of the left oil supplementing spool is connected with the left side cavity of the left oil supplementing nozzle; the right side of the left oil supplementing nozzle is connected with the overflow cavity; the nozzle cavity of the left oil supplementing nozzle is connected with the thin rod cavity of the left oil supplementing spool through an oil channel; the opening degree of the nozzle cavity and the thin rod cavity is controlled by the displacement of the left oil supplementing spool; the lower side of the left oil supplementing nozzle is connected with the thin rod cavity of the left oil supplementing spool through an oil channel; the upper side of the left oil supplementing nozzle is connected with the overflow cavity; the right oil supplementing spool is slidably installed in the right hole of the housing; the right spring is sleeved in the left end cylinder of the right oil supplementing spool; the left side of the right spring is abutted against the right air pocket collecting nozzle fixed in the right hole; the right air pocket collecting nozzle is a through structure; the right side of the right spring is abutted against the left end surface of the left shoulder of the right oil supplementing spool; the right end of the right oil supplementing spool is connected with the overflow cavity through an oil channel; the left end of the right oil supplementing spool is connected with the right side cavity of the right oil supplementing nozzle; the left side of the right oil supplementing nozzle is connected with the overflow cavity; the nozzle cavity of the right oil supplementing nozzle is connected with the thin rod cavity of the right oil supplementing spool through an oil channel; the opening degree of the nozzle cavity and the thin rod cavity is controlled by the displacement of the right oil supplementing spool; the lower side of the right oil supplementing nozzle is connected with the thin rod cavity of the right oil supplementing spool through an oil channel; the upper side of the right oil supplementing nozzle is connected with the overflow cavity.

[0012] Further, the oil channel of the oil inlet cavity Ps1 is connected to the oil channel of the installed oil filter; the right side of the left nozzle and the left side of the right nozzle communicate with the overflow cavity.

[0013] Further, the hole diameter of the oil inlet hole component is larger than the hole diameter of the oil outlet hole component; the outer diameter of the bladder is 2 / 3-3 / 4 of the hole diameter of the oil inlet channel.

[0014] Further, there are holes with different sizes on the connecting plate; the capillary pipes are welded to the connecting plate, and the pipe diameter of the capillary pipes is the same as the hole diameter of the corresponding holes of the connecting plate; the capillary pipes are a group of soft pipes with different lengths and diameters.

[0015] Further, the left oil supplementing valve core and the right oil supplementing valve core have a cylinder degree of 0.001 mm and a roughness of Ra0.1, and the outer diameter is 1 / 5-1 / 6 of the outer diameter of the power valve core.

[0016] Further, the left gas cavity collecting nozzle has a diameter 3 times larger than that of the left oil supplementing nozzle.

[0017] Further, the distance between the left gas cavity collecting nozzle and the left oil supplementing nozzle is not greater than 0.2 mm, and the distance between the left gas cavity collecting nozzle and the lower side of the left nozzle is not greater than 0.5 mm.

[0018] Further, the right gas cavity collecting nozzle has a diameter 3 times larger than that of the right oil supplementing nozzle.

[0019] Further, the distance between the right gas cavity collecting nozzle and the right oil supplementing nozzle is not greater than 0.2 mm, and the distance between the right gas cavity collecting nozzle and the lower side of the right nozzle is not greater than 0.5 mm.

[0020] Beneficial effects

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

[0022] 1) The wave absorbing device is invented, which has a small volume and a simple structure, and can filter hydraulic pulsation in the bladder, and can offset the wave peak and wave trough of the output capillary tube by changing the length and diameter of the capillary tube, thereby reducing the fluctuation of the oil supply pressure. The present application innovatively solves the problem of oil supply pressure fluctuation filtering;

[0023] 2) The gas cavity oil supplementing device is invented, which can quickly capture the gas cavity and quickly supplement it with high-pressure oil, greatly shortening the time of the gas cavity and avoiding the complex structure design, strong sealing and corrosion-resistant materials in the traditional hydraulic system;

[0024] 3) The wave absorbing device is applied to the servo valve for the first time, which can realize high-frequency filtering of the input oil pressure pulsation of the front end, and the movement of the components in the servo valve is stable, without high-frequency pulsation and fatigue damage, thereby avoiding the high-frequency pulsation of the output flow and pressure of the servo valve and improving the output stability;

[0025] 4) The gas cavity oil supplementing device is applied to the servo valve for the first time, which can offset the gas cavity at the nozzle, thereby avoiding the resonance of the armature assembly and the generation of whistling. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a low-noise electro-hydraulic servo valve principle diagram of an embodiment of the present application;

[0027] Figure 2 is a wave absorbing device structure diagram of an embodiment of the present application;

[0028] Figure 3Fig. 1 is a structural diagram of a capillary tube and a connecting plate;

[0029] Wherein, 1, upper magnetic conductor, 2, coil, 3, permanent magnet, 4, armature, 5, lower magnetic conductor, 6, baffle, 7, left nozzle, 8, left air pocket collecting nozzle, 9, left spring, 10, left oil supplement valve core, 11, left oil supplement nozzle, 12, left throttle hole component, 13, oil filter, 14, valve sleeve, 15, power valve core, 16, wave absorbing device, 17, feedback rod, 18, right throttle hole component, 19, right oil supplement nozzle, 20, right oil supplement valve core, 21, right spring, 22, right air pocket collecting nozzle, 23, right nozzle, 24, shell, 25, spring tube; 16A, oil inlet hole component, 16B, skin bag, 16C, oil outlet hole component, 16D, connecting plate, 16E, capillary tube. DETAILED DESCRIPTION

[0030] The features and illustrative embodiments of various aspects of the present application will be described below in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without some or all of these specific details. The description of the embodiments is merely intended to provide a better understanding of the present application by showing examples of the present application. The present application is in no way limited to any particular set of details disclosed below, but covers any modifications, substitutions, and refinements of structure, method, device, etc. without departing from the spirit of the present application. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessary obscuring of the present application.

[0031] It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict, and each embodiment can be mutually referenced and quoted. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] Reference Figure 1 The present application provides a low-noise electro-hydraulic servo valve, which comprises a torque motor part, a hydraulic amplification stage part, a power stage spool valve part, a wave absorbing device, and an air pocket oil supplement part.

[0033] The torque motor part is arranged on the shell 24 and comprises an upper magnetic conductor 1, a coil 2, a permanent magnet 3, an armature 4, a lower magnetic conductor 5, a spring tube 25, and a feedback rod 17. The permanent magnet 3 is arranged between the upper magnetic conductor 1 and the lower magnetic conductor 5. The coil 2 is wound on the armature 4. The armature 4 and the upper end of the feedback rod 17 are installed on the spring tube 25. The lower end of the feedback rod is connected with the power valve core 15 of the power stage spool valve part.

[0034] The hydraulic amplification stage part comprises a left nozzle 7, a baffle 6, a right nozzle 23, a left throttle hole part 12, an oil filter 13, a right throttle hole part 18, the left nozzle 7 and the right nozzle 23 are symmetrically installed on the shell, the baffle 6 is arranged between the left nozzle 7 and the right nozzle 23, the left throttle hole part 12 and the right throttle hole part 18 are respectively sleeved on the left end and the right end of the oil filter 13, and the three parts are jointly arranged in the oil filter hole of the shell 24;

[0035] The left end of the left nozzle 7, the left end of the left throttle hole part 12 and the left end of the power valve core 15 are connected through the oil channel of the shell 24; the right end of the right nozzle 23, the right end of the right throttle hole part 18 and the right end of the power valve core 15 are connected through the oil channel of the shell 24;

[0036] The power stage spool part comprises a valve sleeve 14 and a power valve core 15; the power valve core 15 is installed in the valve sleeve 14 and is jointly arranged in the valve sleeve hole of the shell 24;

[0037] The wave elimination device comprises an oil inlet hole part 16A, a bladder 16B, an oil outlet hole part 16C, a connecting plate 16D and a capillary pipe 16E; the lower end of the oil inlet hole part 16A is connected with the shell 24 and communicates with the oil inlet cavity Ps, the upper end of the oil inlet hole part 16A is connected with the bladder 16B, the upper end of the bladder 16B is connected with the oil outlet hole part 16C, the upper end of the oil outlet hole part 16C is connected with the connecting plate 16D, and the upper end of the connecting plate 16D is connected with a plurality of capillary pipes 16E which are different in length and pipe diameter;

[0038] The air cavity oil supplementing part comprises a left air cavity collecting nozzle 8, a left spring 9, a left oil supplementing valve core 10, a left oil supplementing nozzle 11, a right oil supplementing nozzle 19, a right oil supplementing valve core 20, a right spring 21 and a right air cavity collecting nozzle 22;

[0039] The left oil supplementing valve core 10 is slidably installed in the left hole of the shell 24, the left spring 9 is sleeved in the right end cylinder of the left oil supplementing valve core 10, the right side of the left spring 9 is abutted against the left air cavity collecting nozzle 8 which is fixed in the left hole, the left air cavity collecting nozzle 8 is a through structure, and the left side of the left spring 9 is abutted against the right end face of the right protruding shoulder of the left oil supplementing valve core 10; the left end of the left oil supplementing valve core 10 is connected with the overflow cavity through the oil channel, and the right end is connected with the left side cavity of the left oil supplementing nozzle 11; the right side of the left oil supplementing nozzle 11 is connected with the overflow cavity, the left nozzle cavity and the thin rod cavity of the left oil supplementing valve core 10 are connected through the oil channel, and the opening degree of the left nozzle cavity and the thin rod cavity of the left oil supplementing valve core 10 is controlled by the displacement of the left oil supplementing valve core 10; the lower side of the left oil supplementing nozzle 11 is connected with the thin rod cavity of the left oil supplementing valve core 10 through the oil channel, and the upper side is connected with the overflow cavity;

[0040] The right oil supplement valve core 20 is slidingly installed in the right hole of the shell 24, the right spring 21 is sleeved on the left end cylinder of the right oil supplement valve core 20, the left side of the right spring 21 is abutted against the right air pocket collecting nozzle 22 fixed in the right hole, the right air pocket collecting nozzle 22 is a through structure, and the right side of the right spring 21 is abutted against the left end face of the left protruding shoulder of the right oil supplement valve core 20; the right end of the right oil supplement valve core 20 is connected with the overflow cavity through an oil channel, and the left end is communicated with the right side cavity of the right oil supplement nozzle 19; the left side of the right oil supplement nozzle 19 is connected with the overflow cavity, the right nozzle cavity is communicated with the thin rod cavity of the right oil supplement valve core 20 through an oil channel, and the opening degree of the right nozzle cavity and the thin rod cavity of the right oil supplement valve core 20 is controlled by the displacement of the right oil supplement valve core 20; the lower side of the right oil supplement nozzle 19 is connected with the thin rod cavity of the right oil supplement valve core 20 through an oil channel, and the upper side is connected with the overflow cavity; the oil inlet cavity Ps1 is connected with the oil channel of the installed oil filter 13; the right side of the left nozzle 7 and the left side of the right nozzle 23 are communicated with the overflow cavity.

[0041] In the application, the hole diameter of the oil inlet hole part 16A is larger than the hole diameter of the oil outlet hole part 16C; in this way, the inside of the bladder 16B can retain a certain pressure, and the bladder 16B can absorb a certain pressure fluctuation.

[0042] The outer diameter of the bladder 16B is 2 / 3-3 / 4 of the hole diameter of the oil inlet channel; in this way, when the bladder 16B is inflated by pressure, the oil inlet channel cannot restrict the deformation of the bladder 16B.

[0043] There are holes with different sizes on the connecting plate 16D, the capillary channel 16E is welded to the connecting plate 16D, and the hole diameter of the capillary channel 16E is the same as the hole diameter of the corresponding hole of the connecting plate 16D; the capillary channel 16E is a group of hoses with different lengths and hole diameters; in this way, the phase of the hydraulic oil pulsation of each capillary channel 16E is delayed differently, the amplitude is attenuated, the wave crest and the wave trough of the output multiple beam pulsation pressure waves interfere with and offset each other, and filtering is formed.

[0044] In the application, the roundness of the left oil supplement valve core 10 and the right oil supplement valve core 20 is 0.001 mm, and the roughness is Ra0.1; in this way, the left oil supplement valve core 10 can move smoothly in the left hole of the shell 22, and the valve core has good wear resistance and long service life.

[0045] The outer diameter is 1 / 5-1 / 6 of the outer diameter of the power valve core 15; in this way, a very small flow can be used to quickly drive the left oil supplement valve core 10 and the right oil supplement valve core 20, and the movement speed is fast, which is beneficial to quickly supplement the air pocket.

[0046] The hole diameter of the left air pocket collecting nozzle 8 is 3 times larger than the hole diameter of the left oil supplement nozzle 11, and the hole diameter of the right air pocket collecting nozzle 22 is 3 times larger than the hole diameter of the right oil supplement nozzle 19; in this way, the left air pocket collecting nozzle 8 and the right air pocket collecting nozzle 22 can more efficiently collect the air pocket, and the left oil supplement nozzle 11 and the right oil supplement nozzle 19 can accurately and quickly supplement the pressure of the air pocket.

[0047] The distance between the left air pocket collecting nozzle 8 and the left oil supplementing nozzle 11 is not greater than 0.2 mm, and the distance between the right air pocket collecting nozzle 22 and the right oil supplementing nozzle 19 is not greater than 0.2 mm; thus, after the left oil supplementing nozzle 11 and the right oil supplementing nozzle 19 supplement pressure to make the air pocket disappear, the left air pocket collecting nozzle 8 and the right air pocket collecting nozzle 22 can quickly accept the change of the air pocket, and the air pocket oil supplementing part avoids performing excessive oil supplementing.

[0048] The distance between the left air pocket collecting nozzle 8 and the lower side of the left nozzle 7 is not greater than 0.5 mm, and the distance between the right air pocket collecting nozzle 22 and the lower side of the right nozzle 23 is not greater than 0.5 mm; thus, the left air pocket collecting nozzle 8 and the right air pocket collecting nozzle 22 can collect the air pocket more efficiently.

[0049] The working principle of the low-noise electro-hydraulic servo valve is that the input oil supply pressure Ps of the hydraulic pump servo valve is filtered by the wave elimination device to form a stable pressure, and the stable pressure is supplied to the hydraulic amplification stage and the power stage spool valve. When the coil 2 inputs a positive current, the armature 4 is rotated counterclockwise around the spring tube 25 rotation center under the action of the electromagnetic force, drives the baffle 6 to deflect to the right, and then the left side pressure of the left nozzle 7 is reduced, the right side pressure of the right nozzle 23 is increased, the air pocket oil supplementing part compensates the air pocket, the left side pressure fluctuation of the left nozzle 7 and the right side pressure fluctuation of the right nozzle 23 are reduced, and the stable hydraulic pressure acts on the left and right end faces of the power valve core 15, so that the power valve core 15 moves to the left, the high-pressure oil is output through the opening of the power valve core 15 and the valve sleeve 16, and in addition, the displacement of the power valve core 15 is transmitted to the spring tube 25 through the feedback rod 18, so that force balance is finally realized, 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 the above. The servo valve also comprises a wave elimination device and an air pocket oil supplementing part, and the working process is as follows:

[0050] The working principle of the wave elimination device is that the hydraulic oil with high-frequency pulsation passes through the wave elimination device to flow out, and is filtered through four filters, and the specific process is as follows,

[0051] ①, the throttle hole of the oil inlet hole part 16A enters the rubber bag 16B, and is filtered for the first time;

[0052] ②, the rubber bag 16B deforms under pressure, and the rubber bag 16B is a rubber product with a very low response frequency, so that the high-frequency pulsation component can be filtered for the second time;

[0053] ③, the hydraulic oil enters the throttle hole of the oil outlet hole part 16C, and the high-frequency pulsation component can be filtered for the third time;

[0054] ④、Hydraulic oil into the connecting plate 16D hole small hole, and then into the capillary channel 16E, capillary channel 16E is a group of thin-walled hose, and long and short, the phase of the hydraulic oil pulse from each capillary channel 16E is delayed, the amplitude is attenuated, and finally output multiple beam pulse pressure wave peak and trough interfere with each other, mutual offset, forming the fourth filter.

[0055] Finally, the effect of the pulsating pressure oil into a smooth pressure oil is realized, the servo valve works smoothly, and the noise is reduced.

[0056] Wherein, the air pocket oil supplement part working principle:

[0057] When the left nozzle 7 sprays high-speed oil or oil with a certain amount of gas, it is easy to produce an air pocket near the left nozzle 7, the air pocket is extremely low negative pressure, at this time the left air pocket collecting nozzle 8 can capture the negative pressure, the pressure value is introduced to the right end of the left oil supplement valve core 10, the pressure of the left end of the left oil supplement valve core 10 is much higher than that of the right end, the left oil supplement valve core 10 moves rapidly to the right, the left nozzle cavity and the left oil supplement valve core 10 thin rod cavity are communicated, the hydraulic oil in the left nozzle cavity flows rapidly into the left oil supplement nozzle 11 through the oil way, the left oil supplement nozzle 11 sprays high-pressure oil, rapidly supplements the air pocket, the air pocket disappears, the pressure of the right end of the left oil supplement valve core 10 recovers rapidly to the overflow cavity pressure, the left oil supplement valve core 10 returns rapidly to the initial position, and the left nozzle cavity and the left oil supplement valve core 10 thin rod cavity are communicated and closed.

[0058] When the right nozzle 23 sprays high-speed oil or oil with a certain amount of gas, it is easy to produce an air pocket near the right nozzle 23, the air pocket is extremely low negative pressure, at this time the right air pocket collecting nozzle 22 can capture the negative pressure, the pressure value is introduced to the left end of the right oil supplement valve core 20, the pressure of the left end of the right oil supplement valve core 20 is much higher than that of the right end, the right oil supplement valve core 20 moves rapidly to the left, the right nozzle cavity and the right oil supplement valve core 20 thin rod cavity are communicated, the hydraulic oil in the right nozzle cavity flows rapidly into the right oil supplement nozzle 19 through the oil way, the right oil supplement nozzle 19 sprays high-pressure oil, rapidly supplements the air pocket, the air pocket disappears, the pressure of the left end of the right oil supplement valve core 20 recovers rapidly to the overflow cavity pressure, the right oil supplement valve core 20 returns rapidly to the initial position, and the left nozzle cavity and the right oil supplement valve core 20 thin rod cavity are communicated and closed.

[0059] This process can quickly eliminate the air pocket near the left nozzle 7 and the right nozzle 23, avoid the huge pressure fluctuation and noise caused by the death process of the air pocket, and further avoid the high-frequency oscillation of the baffle, so that the left and right pressures transmitted to the power valve core 15 do not contain pulsation components, the power valve core 15 moves stably, and the servo valve howling problem is solved.

[0060] It should be pointed out that the above examples are only used to illustrate the technical solutions of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application.

Claims

1. A low noise electro-hydraulic servo valve characterized by, The torque motor part is arranged on the shell, and the hydraulic amplification stage part, the power stage spool part, the wave absorbing device and the air cavity oil supplement part are arranged in the shell; The torque motor part comprises an upper magnetic conductor, a coil, a permanent magnet, an armature, a lower magnetic conductor, a spring tube and a feedback rod, the permanent magnet is arranged between the upper magnetic conductor and the lower magnetic conductor, the coil is wound on the armature, the armature and the upper end of the feedback rod are installed on the spring tube, and the lower end of the feedback rod is connected with the power valve core of the power stage spool part; The hydraulic amplification stage part comprises a left nozzle, a baffle, a right nozzle, a left throttle hole component, an oil filter and a right throttle hole component, the left nozzle and the right nozzle are symmetrically arranged in the shell, the baffle is arranged between the left nozzle and the right nozzle, the left throttle hole component and the right throttle hole component are respectively sleeved on the left end and the right end of the oil filter, and the three parts are jointly arranged in the oil filter hole of the shell; the left end of the left nozzle and the left end of the left throttle hole component are connected with the left end of the power valve core through the oil channel of the shell; the right end of the right nozzle and the right end of the right throttle hole component are connected with the right end of the power valve core through the oil channel of the shell; The power stage spool part comprises a valve sleeve and a power valve core, the power valve core is arranged in the valve sleeve, and the valve sleeve and the power valve core are jointly arranged in the valve sleeve hole of the shell; The wave absorbing device comprises an oil inlet hole component, a rubber bag, an oil outlet hole component, a connecting plate and a capillary pipeline, the lower end of the oil inlet hole component is connected with the shell and communicates with an oil inlet cavity Ps, the upper end of the oil inlet hole component is connected with the rubber bag, the upper end of the rubber bag is connected with the oil outlet hole component, the upper end of the oil outlet hole component is connected with the connecting plate, and the upper end of the connecting plate is connected with a plurality of capillary pipelines with different lengths and diameters; The air cavity oil supplement part comprises a left air cavity collecting nozzle, a left spring, a left oil supplement valve core, a left oil supplement nozzle, a right oil supplement nozzle, a right oil supplement valve core, a right spring and a right air cavity collecting nozzle, the left oil supplement valve core is slidably arranged in the left hole of the shell, the left spring is sleeved on the right end of the left oil supplement valve core, the right side of the left spring is abutted against the left air cavity collecting nozzle fixed in the left hole, the left air cavity collecting nozzle is a through structure, and the left side of the left spring is abutted against the right end surface of the right shoulder of the left oil supplement valve core; the left end of the left oil supplement valve core is connected with an overflow cavity through an oil channel, and the right end is connected with the left side cavity of the left oil supplement nozzle; the right side of the left oil supplement nozzle is connected with the overflow cavity, the left nozzle cavity and the thin rod cavity of the left oil supplement valve core are connected through the oil channel, and the opening degree of the left nozzle cavity and the thin rod cavity of the left oil supplement valve core is controlled through the displacement of the left oil supplement valve core; the lower side of the left oil supplement nozzle is connected with the thin rod cavity of the left oil supplement valve core through the oil channel, and the upper side is connected with the overflow cavity; the right oil supplement valve core is slidably arranged in the right hole of the shell, the right spring is sleeved on the left end of the right oil supplement valve core, the left side of the right spring is abutted against the right air cavity collecting nozzle fixed in the right hole, the right air cavity collecting nozzle is a through structure, and the right side of the right spring is abutted against the left end surface of the left shoulder of the right oil supplement valve core; the right end of the right oil supplement valve core is connected with the overflow cavity through the oil channel, and the left end is connected with the right side cavity of the right oil supplement nozzle; the left side of the right oil supplement nozzle is connected with the overflow cavity, the right nozzle cavity and the thin rod cavity of the right oil supplement valve core are connected through the oil channel, and the opening degree of the right nozzle cavity and the thin rod cavity of the right oil supplement valve core is controlled through the displacement of the right oil supplement valve core; the lower side of the right oil supplement nozzle is connected with the thin rod cavity of the right oil supplement valve core through the oil channel, and the upper side is connected with the overflow cavity.

2. A low noise electro-hydraulic servo valve as claimed in claim 1, characterized in that The oil channel of the oil inlet cavity Ps1 is connected to the oil channel of the installed oil filter, and the right side of the left nozzle and the left side of the right nozzle communicate with the overflow cavity.

3. A low noise electro-hydraulic servo valve as claimed in claim 1, wherein, The hole diameter of the oil inlet hole part is greater than that of the oil outlet hole part; the outer diameter of the bladder is 2 / 3-3 / 4 of the hole diameter of the oil inlet channel.

4. A low noise electro-hydraulic servo valve as claimed in claim 1, wherein, Different-sized holes are formed on the connecting plate, the capillary pipe is welded to the connecting plate, and the pipe diameter of the capillary pipe is the same as the hole diameter of the corresponding hole of the connecting plate; the capillary pipe is a group of hoses with different lengths and different hole diameters.

5. A low-noise electro-hydraulic servo valve according to claim 1, characterized in that: The left oil supplement valve core and the right oil supplement valve core have a cylindricity of 0.001 mm and a roughness of Ra0.1, and the outer diameters of the left oil supplement valve core and the right oil supplement valve core are 1 / 5-1 / 6 of the outer diameter of the power valve core.

6. A low noise electro-hydraulic servo valve as claimed in claim 1, wherein, The hole diameter of the left gas pocket collecting nozzle is 3 times greater than that of the left oil supplement nozzle.

7. A low noise electro-hydraulic servo valve as claimed in claim 6, characterised in that, The distance between the left gas pocket collecting nozzle and the left oil supplement nozzle is not greater than 0.2 mm, and the distance between the left gas pocket collecting nozzle and the lower side of the left nozzle is not greater than 0.5 mm.

8. A low noise electro-hydraulic servo valve as claimed in claim 1, wherein, The hole diameter of the right gas pocket collecting nozzle is 3 times greater than that of the right oil supplement nozzle.

9. A low-noise electro-hydraulic servo valve according to claim 8, characterized in that: The distance between the right gas pocket collecting nozzle and the right oil supplement nozzle is not greater than 0.2 mm, and the distance between the right gas pocket collecting nozzle and the lower side of the right nozzle is not greater than 0.5 mm.

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