Conical surface throttling control type electro-hydraulic servo valve and working method

Abstract

The invention belongs to the technical field of mechanical hydraulic pressure, and discloses a conical surface throttling control type electro-hydraulic servo valve and a working method, and the conical surface throttling control type electro-hydraulic servo valve is mainly composed of a linear force motor, a transmission hinge, a torsion bar, a baffle, a throttling frustum, a nozzle, a valve sleeve, a valve element and other parts. The linear force motor drives the torsion bar to drive the baffle to move, the baffle drives the frustum to move and generates throttling change with the nozzle, and therefore pressure difference is generated at the two ends of the valve element to drive the valve element to move. A frustum and nozzle throttling mode is used, so that the oscillation problem caused by air holes is avoided; the first stage adopts a frustum and nozzle variable throttling mode, a gap is small, and internal leakage is small; two-stage throttling control is used, the pressure gain of a hydraulic amplification stage is improved, and then the anti-pollution capacity of the servo valve is improved; the torsion bar is directly driven by the linear force motor, the structure is simple, assembling is easy, and reliability is high. The problems that a traditional electro-hydraulic servo valve is large in pilot inner leakage, weak in anti-pollution capacity, complex in torque motor, large in assembly difficulty, poor in stability and the like are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical hydraulics, and in particular relates to a cone throttling control type electro-hydraulic servo valve and a working method thereof. Background Art

[0002] Electro-hydraulic servo valve is a precision hydraulic control element, mainly used in hydraulic servo control system, widely used in aerospace field. With the vigorous development of aerospace, the demand for servo valves has gradually increased, the important role of servo valves has become more and more obvious, and the demand for upgrading has become more and more intense. At present, the main form of electro-hydraulic servo valve is a two-stage servo valve, and the front drive stage is nozzle-baffle type, jet tube type, and deflector jet type. There are leaks in the front stage and slide valve stage of the two-stage servo valve, so the internal leakage is large; in addition, the torque motor is a precision part, and the existing torque motor part has many parts. The assembly of multiple parts drives the movement of the baffle, which is difficult to assemble and has poor stability; the first-stage throttling of the traditional nozzle-baffle valve is throttled through a fixed throttle hole, which has large leakage and cannot produce a variable pressure difference. It can only rely on the nozzle-baffle part to generate a pressure difference to drive the valve core, so the valve core driving force is small, the pressure gain at the nozzle-baffle is small, and the anti-pollution ability of the valve core is poor; the oil ejected from the traditional nozzle hits the baffle vertically, and due to the fast flow rate of the fluid, cavitation is easy to occur, so the traditional servo valve is prone to oscillation, howling and other problems. Summary of the invention

[0003] Purpose of the present invention:

[0004] In order to solve the shortcomings of existing electro-hydraulic servo valves such as large internal leakage, complex torque motor structure, small valve core driving force, weak anti-pollution ability, and howling, the present invention proposes a conical throttling control electro-hydraulic servo valve and a working method.

[0005] The technical solution of the present invention is as follows:

[0006] On one hand, the present invention designs a cone throttling control type electro-hydraulic servo valve, which includes a linear force motor, a first transmission hinge, a first-stage torsion bar, a transmission rod, a second connecting hinge, a second-stage torsion bar, a second-stage right nozzle, a second-stage baffle, a second-stage left nozzle, a feedback rod, a valve sleeve, a valve core, a first-stage left nozzle, a first-stage baffle, a first-stage right nozzle, a second-stage left cone, a second-stage right cone, a first-stage left cone, and a first-stage right cone;

[0007] The linear force motor is installed on the valve body and fixed by screws; the output rod of the linear force motor acts on the first-stage torsion bar through the first transmission hinge, and the first transmission hinge is connected to the second connection hinge through the transmission rod, thereby transmitting the torque to the second-stage torsion bar;

[0008] The first-stage baffle is fixedly connected to the first-stage torsion bar, and the first-stage left cone and the first-stage right cone are respectively arranged on the left and right sides of the first-stage baffle, and the first-stage left nozzle and the first-stage right nozzle are installed in the corresponding holes of the shell, respectively on the left side of the first-stage left cone and on the right side of the first-stage right cone;

[0009] The second-stage baffle, the second-stage torsion bar and the feedback bar are fixedly connected to form an armature assembly, and the second-stage left cone and the second-stage right cone are respectively arranged on the left and right sides of the second-stage baffle, and the second-stage left nozzle and the second-stage right nozzle are installed in corresponding holes of the housing, respectively on the left side of the second-stage left cone and the right side of the second-stage right cone;

[0010] The valve sleeve is arranged below the plane where the nozzle is located, the valve core is slidably arranged in the valve sleeve, a small ball is arranged at the end of the feedback rod, and the gap of the small ball is inserted into the annular groove of the valve core.

[0011] Furthermore, in the electro-hydraulic servo valve structure designed as above, the right side of the first-stage right nozzle is connected to the left side of the second-stage left nozzle through an oil channel, and is connected to the left end face of the valve core through the oil channel; the left side of the first-stage left nozzle is connected to the right side of the first-stage right nozzle through an oil channel, and is connected to the right end face of the valve core through the oil channel; the oil supply pressure Ps is connected to the lower side of the first-stage baffle through the oil channel; and the return oil pressure R is connected to the lower side of the second-stage baffle through the oil channel.

[0012] Furthermore, in the electro-hydraulic servo valve structure designed as above, the internal spherical surface roughness of the transmission hinge and the connecting hinge is better than Ra0.1, the transmission clearance between the spherical surface and the shell is 0.001mm~0.003mm, and the spherical surface is nitrided and hardened, and has strong wear resistance.

[0013] Furthermore, in the electro-hydraulic servo valve structure designed as above, the first-stage torsion bar and the first-stage baffle are interference fit, and are fixedly connected at the connection position by laser welding to form a first-stage armature assembly; the second-stage torsion bar and the first-stage and second-stage baffles and the feedback rod are interference fit, and are fixedly connected at the connection position by laser welding to form a second-stage armature assembly.

[0014] Furthermore, the ratio of the nozzle inner hole length L to the aperture D of the first-stage left nozzle, the first-stage right nozzle, the second-stage left nozzle, and the second-stage right nozzle is ≤2, the orifice ensures that the roundness is better than R0.003mm, and the orifice roundness is better than 0.01mm; too large an aspect ratio will affect the output linearity.

[0015] Furthermore, the cone angle P of the second-stage left cone, the second-stage right cone, the first-stage left cone, and the first-stage right cone is in the range of 30 to 45. If it is too large, the pressure gain will be low, which will affect the overall dynamics of the servo valve. The cone roundness is better than 0.01mm, the cone surface roughness is better than Ra0.1, and the contact part between the cone and the baffle has a fillet of R0.1 to 0.3.

[0016] Furthermore, the coaxiality between the outer cone surface of the first-stage left cone and the inner hole of the first-stage left nozzle is better than 0.01 mm; the coaxiality between the other three cones and the nozzle is better than 0.01 mm.

[0017] Furthermore, the first-stage left cone, the first-stage right cone and the first-stage baffle are processed in combination, so as to ensure the consistency of the processing of the two cones. The second-stage left cone, the second-stage right cone and the second-stage baffle are processed in combination.

[0018] Furthermore, when assembling the electro-hydraulic servo valve designed as above, the armature assembly is installed first, the first-stage baffle is fixed, hydraulic oil is passed through the lower side of the first-stage baffle, and then the first-stage left nozzle is installed and slowly pushed forward until the gap formed by the first-stage left nozzle and the first-stage left cone reaches the set flow resistance, that is, the first-stage left nozzle reaches the specified position; the other three nozzles and cones are debugged in the same way.

[0019] The present invention also proposes a specific working method of the electro-hydraulic servo valve designed as above. The servo valve adopts the conical throttling control electro-hydraulic servo valve designed as above, and the specific working process is: when the linear force motor inputs a positive current, its internal armature generates an electromagnetic force extending outward, and transmits the torque to the first-stage torsion bar through the transmission hinge, and at the same time transmits the torque to the second-stage torsion bar through the transmission rod and the connecting hinge; the first-stage torsion bar drives the first-stage baffle, the first-stage left cone, and the first-stage right cone to move rightward, and the second-stage torsion bar drives the second-stage baffle, the second-stage left cone and the second-stage right cone to move rightward; at this time, the gap formed by the first-stage left cone and the first-stage left nozzle increases, and the gap formed by the first-stage right cone and the first-stage right nozzle increases. Decreases, thus, the pressure on the left side of the first-stage left nozzle increases, and the pressure on the right side of the first-stage right nozzle decreases; the gap formed by the second-stage left cone and the second-stage left nozzle increases, and the gap formed by the second-stage right cone and the second-stage right nozzle decreases, the pressure on the left side of the second-stage left nozzle decreases, and the pressure on the right side of the second-stage right nozzle increases; then, the pressure on the left side of the valve core decreases, and the pressure on the right side of the valve core increases, the valve core moves to the left, and the valve core displacement is fed back to the second-stage torsion bar through the feedback rod, forming force feedback control; finally, the valve core output displacement is proportional to the input signal, and the output flow is proportional to the input valve core displacement, which is manifested as the output flow is proportional to the input signal; similarly, when the linear force motor inputs a negative current, the movement direction of the internal parts of the servo valve is opposite to the above.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1) The first stage hydraulic amplification stage adopts a frustum and nozzle hole variable throttling method, so that the servo valve can achieve the effect of hydraulic amplification of the first and second stages at the same time for the same input signal, so that the pressure gain of the hydraulic amplification stage is greatly improved. Compared with the traditional servo valve with single-stage hydraulic amplification, this servo valve can output a larger power level flow with a small drive motor. In addition, compared with the traditional servo valve, the valve core is driven by 1.5 to 2 times more force, the thrust of shearing excess objects is large, and the servo valve's anti-pollution ability is greatly improved.

[0022] 2) The first-stage hydraulic amplifier adopts a variable throttling method of cone and nozzle hole, with small gap and small leakage in the first stage, avoiding the large leakage problem caused by the fixed aperture throttling hole in the first stage of the traditional servo valve.

[0023] 3) A linear force motor is used to directly drive the torsion bar to drive the movement of the baffle. The driving method is simple and avoids the problems of traditional servo valve torque motors with many parts, difficult assembly, and easy deformation that causes valve zero position changes.

[0024] 4) The variable hydraulic amplifier stage adopts the frustum and nozzle throttling control mode. The hydraulic oil moves along the frustum surface at the outlet nozzle, and is sprayed at a certain angle through the gap formed by the cone surface and the nozzle, and then can hit the baffle at a larger angle, which alleviates the impact of the oil and makes it difficult to form negative pressure near the baffle, thereby reducing the formation of cavitation and improving the stability of the servo valve. It solves the problem of cavitation caused by the oil ejected from the traditional nozzle vertically hitting the baffle, which is easy to cause oscillation, howling and other problems.

[0025] 5) The nozzle arranged according to the present structure only needs to ensure the sharp edge and a certain roundness of the orifice, and the processing difficulty is small. It avoids the problems of the traditional nozzle outlet having a tiny ring, and the high coaxiality requirements of the inner and outer rings, the high processing difficulty, and the low yield rate.

[0026] 6) The elastic element uses a torsion bar. The elastic part of the torsion bar is larger in size, has low precision requirements, and is easy to process. This avoids the use of spring tubes in traditional servo valves. Traditional spring tubes have thin walls, are difficult to process, have high material stiffness requirements, and have short fatigue life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a principle diagram of a cone throttling control type electro-hydraulic servo valve according to an embodiment of the present invention;

[0028] Figure 2 is a nozzle diagram of an embodiment of the present invention;

[0029] Figure 3 It is a partial illustration of a two-stage frustum-nozzle two-stage variable hydraulic amplification stage of an embodiment of the present invention;

[0030] Among them, the linear force motor 1, the transmission hinge 2, the first-stage torsion bar 3, the transmission rod 4, the connecting hinge 5, the second-stage torsion bar 6, the second-stage right nozzle 7, the second-stage baffle 8, the second-stage left nozzle 9, the feedback rod 10, the valve sleeve 11, the valve core 12, the first-stage left nozzle 13, the first-stage baffle 14, the first-stage right nozzle 15, the second-stage left cone 16, the second-stage right cone 17, the first-stage left cone 18, and the first-stage right cone 19. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the present invention is described in detail below in conjunction with the drawings or specific implementation cases of the specification. It should be noted that some but not all of the disclosed examples are shown in the drawings. In fact, many different examples can be described and these examples should not be understood as being limited to the examples set forth herein. On the contrary, these examples are described so that the positive effects of the present invention are more reflected, and any parts not detailed in the text are regarded as known techniques or conventional technical means in the art.

[0032] See attached Figures 1 to 3 The present invention specifically designs a cone throttling control type electro-hydraulic servo valve, including a linear force motor 1, a first transmission hinge 2, a first-stage torsion bar 3, a transmission rod 4, a second connecting hinge 5, a second-stage torsion bar 6, a second-stage right nozzle 7, a second-stage baffle 8, a second-stage left nozzle 9, a feedback rod 10, a valve sleeve 11, a valve core 12, a first-stage left nozzle 13, a first-stage baffle 14, a first-stage right nozzle 15, a second-stage left cone 16, a second-stage right cone 17, a first-stage left cone 18, and a first-stage right cone 19;

[0033] The linear force motor 1 is installed on the valve body and fixed by screws; the output rod of the linear force motor 1 acts on the first-stage torsion bar 3 through the first transmission hinge 2, and the first transmission hinge 2 is connected to the second connecting hinge 5 through the transmission rod 4, thereby transmitting the torque to the second-stage torsion bar 6.

[0034] The first-stage baffle 14 is fixedly connected to the first-stage torsion bar 3. A first-stage left cone 18 and a first-stage right cone 19 are respectively arranged on the left and right sides of the first-stage baffle 14. The first-stage left nozzle 13 and the first-stage right nozzle 15 are installed in corresponding holes of the shell, respectively on the left side of the first-stage left cone 18 and on the right side of the first-stage right cone 19.

[0035] The second-stage baffle 8, the second-stage torsion bar 6 and the feedback rod 10 are fixedly connected to form an armature assembly. The second-stage left cone 16 and the second-stage right cone 17 are respectively arranged on the left and right sides of the second-stage baffle 8. The second-stage left nozzle 9 and the second-stage right nozzle 7 are installed in the corresponding holes of the shell, respectively on the left side of the second-stage left cone 16 and the right side of the second-stage right cone 17.

[0036] The valve sleeve 11 is arranged below the plane where the nozzle is located, the valve core 12 is slidably arranged in the valve sleeve 11, and a small ball is arranged at the end of the feedback rod 10, and the small ball gap is inserted into the annular groove of the valve core 12.

[0037] Based on the structural design of the above-mentioned electro-hydraulic servo valve, in an implementable case, the right side of the first-stage right nozzle 15 is connected to the left side of the second-stage left nozzle 9 through an oil channel, and is connected to the left end face of the valve core 12 through the oil channel; the left side of the first-stage left nozzle 13 is connected to the right side of the first-stage right nozzle 15 through an oil channel, and is connected to the right end face of the valve core 12 through the oil channel; the oil supply pressure Ps is connected to the lower side of the first-stage baffle 14 through the oil channel; the return oil pressure R is connected to the lower side of the second-stage baffle 8 through the oil channel.

[0038] Based on the structural design of the above-mentioned electro-hydraulic servo valve, in an implementable case, the internal spherical surface roughness of the transmission hinge 2 and the connecting hinge 5 is better than Ra0.1, the transmission clearance between the spherical surface and the shell is 0.001mm~0.003mm, and the spherical surface is nitrided and hardened, with strong wear resistance.

[0039] Based on the structural design of the above-mentioned electro-hydraulic servo valve, in an practicable case, the first-stage torsion bar 3 and the first-stage baffle 14 are interferingly fitted, and are fixedly connected at the connection position by laser welding to form a first-stage armature assembly; the second-stage torsion bar 6 and the first-stage second-stage baffle 8 and the feedback rod 10 are interferingly fitted, and are fixedly connected at the connection position by laser welding to form a second-stage armature assembly;

[0040] Based on the structural design of the above-mentioned electro-hydraulic servo valve, in the feasible cases, the ratio of the nozzle inner hole length L to the aperture D of the first-stage left nozzle 13, the first-stage right nozzle 15, the second-stage left nozzle 9, and the second-stage right nozzle 7 is ≤2, the orifice ensures that the roundness is better than R0.003mm, and the orifice roundness is better than 0.01mm; too large an aspect ratio will affect the output linearity.

[0041] Based on the structural design of the above electro-hydraulic servo valve, in the feasible cases, the cone angle P of the second-stage left cone 16, the second-stage right cone 17, the first-stage left cone 18, and the first-stage right cone 19 is in the range of 30-45. Too large a cone angle will result in low pressure gain and affect the overall dynamics of the servo valve. The cone roundness is better than 0.01mm, the cone surface roughness is better than Ra0.1, and the contact part between the cone and the baffle is guaranteed to have a fillet of R0.1-0.3.

[0042] Based on the structural design of the above-mentioned electro-hydraulic servo valve, in an implementable case, the coaxiality between the outer cone surface of the first-stage left cone 18 and the inner hole of the first-stage left nozzle 13 is better than 0.01 mm; the coaxiality between the remaining three cones and the nozzle is better than 0.01 mm.

[0043] Based on the structural design of the above electro-hydraulic servo valve, in an practicable case, the first-stage left cone 18, the first-stage right cone 19 and the first-stage baffle 14 are processed in combination, so as to ensure the consistency of the processing of the two cones. The second-stage left cone 16, the second-stage right cone 17 and the second-stage baffle 8 are processed in combination.

[0044] Based on the structural design of the above electro-hydraulic servo valve, in the feasible case, the assembly process is as follows: first install the armature assembly, fix the first-stage baffle 14, pass hydraulic oil under the first-stage baffle 14, then install the first-stage left nozzle 13, and slowly push it forward until the gap formed by the first-stage left nozzle 13 and the first-stage left cone 18 reaches the set flow resistance, that is, the first-stage left nozzle 13 reaches the specified position. The other three nozzles and cones are debugged in the same way.

[0045] The conical throttling control type electro-hydraulic servo valve designed as above has a specific working method as follows: when the linear force motor 1 inputs a positive current, its internal armature generates an electromagnetic force extending outward, and transmits the torque to the first-stage torsion bar 3 through the transmission hinge 2, and at the same time transmits the torque to the second-stage torsion bar 6 through the transmission rod 4 and the connecting hinge 5; the first-stage torsion bar 3 drives the first-stage baffle 14, the first-stage left cone 18, and the first-stage right cone 19 to move rightward, and the second-stage torsion bar 6 drives the second-stage baffle 8, the second-stage left cone 16 and the second-stage right cone 17 to move rightward; at this time, the first-stage left cone 18 and the first-stage left nozzle 13 form a The gap between the first-stage right cone 19 and the first-stage right nozzle 15 increases, and the gap between the first-stage right cone 19 and the first-stage right nozzle 15 decreases, so that the pressure on the left side of the first-stage left nozzle 13 increases, and the pressure on the right side of the first-stage right nozzle 15 decreases; the gap between the second-stage left cone 16 and the second-stage left nozzle 9 increases, and the gap between the second-stage right cone 17 and the second-stage right nozzle 7 decreases, the pressure on the left side of the second-stage left nozzle 9 decreases, and the pressure on the right side of the second-stage right nozzle 7 increases; then, the pressure on the left side of the valve core 12 decreases, and the pressure on the right side of the valve core 12 increases, the valve core 12 moves to the left, and the valve core displacement is fed back to the second-stage torsion bar 6 through the feedback rod 10, forming a force feedback control. Finally, the output displacement of the valve core is proportional to the input signal, and the output flow is proportional to the input valve core displacement, which is expressed as the output flow is proportional to the input signal. Similarly, when the linear force motor 1 inputs a negative current, the movement direction of the internal parts of the servo valve is opposite to the above.

[0046] In the conical throttling control type electro-hydraulic servo valve designed by the present invention, the first-stage hydraulic amplifier adopts a variable throttling method of a cone and a nozzle hole, so that the servo valve can realize the hydraulic amplification of the first and second stages at the same time for the same input signal, so that the pressure gain of the hydraulic amplifier part is greatly improved. Compared with the traditional servo valve with single-stage hydraulic amplification, the servo valve can output a larger power level flow using a small drive motor. In addition, compared with the traditional servo valve, the valve core is subjected to a driving force 1.5 to 2 times greater, the thrust of shearing excess material is large, and the anti-pollution ability of the servo valve is greatly improved. In addition, the variable hydraulic amplifier adopts a cone and nozzle throttling control method, and the hydraulic oil moves along the cone surface at the outlet nozzle, and is sprayed at a certain angle through the gap formed by the cone surface and the nozzle, and then can hit the baffle at a larger angle, which alleviates the impact of the oil, and it is not easy to form a negative pressure near the baffle, thereby reducing the formation of cavitation, and improving the stability of the servo valve. The oil ejected from the traditional nozzle vertically hits the baffle to produce cavitation, which is easy to cause oscillation, howling and other problems.

[0047] The above specific implementation methods or cases are only used to explain the technical solutions of the present invention, and are not intended to limit the present application. Any parts not described in detail are deemed to be conventional technical means or common knowledge in the field. It can be understood by ordinary technicians in this field that: based on the design concept of the present application, the technical solutions recorded in the aforementioned implementation methods should be adaptively modified, or some or all of the technical features therein should be replaced by equivalents. These modifications, equivalent replacements, and adaptively improved technical solutions do not depart from the technical essence of the present invention and should all be covered within the protection scope of the present application.

Claims

1. A cone throttling control type electro-hydraulic servo valve, characterized in that: The invention comprises a linear force motor (1), a first transmission hinge (2), a first-stage torsion bar (3), a transmission rod (4), a second connection hinge (5), a second-stage torsion bar (6), a second-stage right nozzle (7), a second-stage baffle (8), a second-stage left nozzle (9), a feedback rod (10), a valve sleeve (11), a valve core (12), a first-stage left nozzle (13), a first-stage baffle (14), a first-stage right nozzle (15), a second-stage left cone (16), a second-stage right cone (17), a first-stage left cone (18), and a first-stage right cone (19); The linear force motor (1) is mounted on the valve body and fixed by screws; the output rod of the linear force motor (1) acts on the first-stage torsion bar (3) through the first transmission hinge (2); the first transmission hinge (2) is connected to the second connection hinge (5) through the transmission rod (4), thereby transmitting the torque to the second-stage torsion bar (6); The first-stage baffle (14) is fixedly connected to the first-stage torsion bar (3), and a first-stage left cone (18) and a first-stage right cone (19) are respectively arranged on the left and right sides of the first-stage baffle (14), and the first-stage left nozzle (13) and the first-stage right nozzle (15) are installed in corresponding holes of the shell, respectively on the left side of the first-stage left cone (18) and on the right side of the first-stage right cone (19); The second-stage baffle (8), the second-stage torsion bar (6) and the feedback rod (10) are fixedly connected to form an armature assembly, and a second-stage left cone (16) and a second-stage right cone (17) are respectively arranged on the left and right sides of the second-stage baffle (8), and the second-stage left nozzle (9) and the second-stage right nozzle (7) are installed in corresponding holes of the housing, respectively on the left side of the second-stage left cone (16) and on the right side of the second-stage right cone (17); The valve sleeve (11) is arranged below the plane where the nozzle is located, the valve core (12) is slidably arranged in the valve sleeve (11), and a small ball is arranged at the end of the feedback rod (10), and the small ball gap is inserted into the annular groove of the valve core (12).

2. A cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: The right side of the first-stage right nozzle (15) is connected to the left side of the second-stage left nozzle (9) through an oil passage, and is connected to the left end face of the valve core (12) through the oil passage; the left side of the first-stage left nozzle (13) is connected to the right side of the first-stage right nozzle (15) through an oil passage, and is connected to the right end face of the valve core (12) through the oil passage; the oil supply pressure Ps is connected to the lower side of the first-stage baffle (14) through the oil passage; and the return oil pressure R is connected to the lower side of the second-stage baffle (8) through the oil passage.

3. A cone throttling control type electro-hydraulic servo valve according to claim 2, characterized in that: The ratio of the nozzle inner hole length L to the aperture D of the first-stage left nozzle (13), the first-stage right nozzle (15), the second-stage left nozzle (9), and the second-stage right nozzle (7) is ≤2, the aperture corner radius is better than R0.003mm, and the aperture roundness is better than 0.01mm; too large an aspect ratio will affect the output linearity.

4. The cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: The internal spherical surface roughness of the transmission hinge (2) and the connecting hinge (5) is better than Ra0.1, the transmission clearance between the spherical surface and the shell is 0.001mm-0.003mm, and the spherical surface is nitrided and hardened, so it has strong wear resistance.

5. The cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: The first-stage torsion bar (3) and the first-stage baffle (14) are interference-fitted and fixedly connected at the connection position by laser welding to form a first-stage armature assembly; the second-stage torsion bar (6) and the first-stage and second-stage baffles (8) and the feedback rod (10) are interference-fitted and fixedly connected at the connection position by laser welding to form a second-stage armature assembly.

6. The cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: The cone angle P of the second-stage left cone (16), the second-stage right cone (17), the first-stage left cone (18), and the first-stage right cone (19) is in the range of 30 to 45. If it is too large, the pressure gain will be low, which will affect the overall dynamics of the servo valve. The cone roundness is better than 0.01 mm, the cone surface roughness is better than Ra0.1, and the contact part between the cone and the baffle has a fillet of R0.1 to 0.

3.

7. The cone throttling control type electro-hydraulic servo valve according to claim 6, characterized in that: The coaxiality between the outer cone surface of the first-stage left cone (18) and the inner hole of the first-stage left nozzle (13) is better than 0.01 mm; the coaxiality between the other three cones and the nozzle is better than 0.01 mm.

8. The cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: The first-stage left cone (18), the first-stage right cone (19) and the first-stage baffle (14) are processed in combination, thus ensuring the consistency of the processing of the two cones; the second-stage left cone (16), the second-stage right cone (17) and the second-stage baffle (8) are processed in combination.

9. The cone throttling control type electro-hydraulic servo valve according to claim 1, characterized in that: During assembly, the armature assembly is first installed, the first-stage baffle (14) is fixed, hydraulic oil is passed through the lower side of the first-stage baffle (14), and then the first-stage left nozzle (13) is installed and slowly pushed forward until the gap formed by the first-stage left nozzle (13) and the first-stage left cone (18) reaches the set flow resistance, that is, the first-stage left nozzle (13) reaches the specified position; the other three nozzles and cones are debugged in the same way.

10. The cone throttling control type electro-hydraulic servo valve according to any one of claims 1 to 9, characterized in that: The working method of the electro-hydraulic servo valve is as follows: when a positive current is input to the linear force motor (1), the armature inside the linear force motor (1) generates an electromagnetic force extending outward, and transmits the torque to the first-stage torsion bar (3) through the transmission hinge (2), and transmits the torque to the second-stage torsion bar (6) through the transmission rod (4) and the connecting hinge (5); the first-stage torsion bar (3) drives the first-stage baffle plate (14), the first-stage left cone (18), and the first-stage right cone (19) to move rightward, and the second-stage torsion bar (6) drives the second-stage baffle plate (8), the second-stage left cone (16), and the second-stage right cone (17) to move rightward; at this time, the gap formed by the first-stage left cone (18) and the first-stage left nozzle (13) increases, and the gap formed by the first-stage right cone (19) and the first-stage right nozzle (15) decreases, so that the first-stage left nozzle (13) The pressure on the left side increases, and the pressure on the right side of the first-stage right nozzle (15) decreases; the gap formed by the second-stage left cone (16) and the second-stage left nozzle (9) increases, and the gap formed by the second-stage right cone (17) and the second-stage right nozzle (7) decreases, the pressure on the left side of the second-stage left nozzle (9) decreases, and the pressure on the right side of the second-stage right nozzle (7) increases; then, the pressure on the left side of the valve core (12) decreases, and the pressure on the right side of the valve core (12) increases, the valve core (12) moves to the left, and the displacement of the valve core is fed back to the second-stage torsion bar (6) through the feedback rod (10), forming force feedback control; finally, the output displacement of the valve core is proportional to the input signal, and the output flow is proportional to the input valve core displacement, which is manifested as the output flow is proportional to the input signal; similarly, when the linear force motor (1) inputs a negative current, the movement direction of the internal parts of the servo valve is opposite to the above.

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