Two-stage rotary valve servo valve and control method thereof

Abstract

The application provides a two-stage rotary valve servo valve, which comprises an integrated motor assembly, a pilot stage valve core assembly, a power stage valve core assembly and a flow distribution valve body assembly; the integrated motor assembly is used for driving the pilot stage valve core assembly to rotate, the pilot stage valve core assembly is used for driving the power stage valve core assembly to rotate under the driving of the integrated motor assembly and realizing mechanical rotation angle feedback. The pilot stage valve core assembly comprises a pilot stage valve core, a floating side plate, a first sealing ring, a second sealing ring and a third sealing ring. The power stage valve core assembly comprises a power stage valve sleeve, a power stage valve core, a rotary valve blade, a rotary valve center spring, a first floating blade, a second floating blade, a first fixed blade and a second fixed blade. The application adopts a modular design, the flow distribution is in a plane flow distribution mode, better sealing effect is achieved through static pressure support, wear compensation is carried out on both sides of the shaft and the diameter, the servo valve feedback mode is mechanical rotation angle feedback through the rotation angle of the valve core, and fast response and high-precision control are realized.

Description

Technical Field

[0001] This invention relates to the field of fluid transmission and control, specifically to a two-stage rotary servo valve and its control method. Background Technology

[0002] With the continuous development of hydraulic or water-driven mechanical equipment such as engineering machinery, mining machinery, and agricultural machinery, the performance requirements of mechanical products are becoming increasingly demanding. Given the huge market demand both domestically and internationally, it is of great significance to provide a servo valve that is simple in structure, easy to control, has high control precision, is applicable to a wide range of media viscosity, and is suitable for ultra-high pressure and high flow applications.

[0003] Existing servo valves are mainly spool valves. However, firstly, spool valve cores are subject to complex forces and are prone to wear and leakage, resulting in a high failure rate, poor product consistency, and limitations in high-pressure, high-flow-rate applications due to structural constraints. Secondly, most existing servo valves use hydraulic oil as the medium, which significantly reduces efficiency or even causes unstable operation with low-viscosity fluids such as water. Finally, existing digital valve technology has complex feedback loops, often employing multiple mechanical structures to achieve closed-loop control. This complex structure leads to high product costs, large errors, and hinders widespread application. Therefore, research and analysis highlight the urgent need to develop a servo valve suitable for various viscosities and applicable to ultra-high-pressure, high-flow-rate applications. Summary of the Invention

[0004] To address the shortcomings of the prior art, this invention provides a two-stage rotary servo valve and its control method. The servo valve has two stages: a pilot valve core and a power stage valve core. The opening of the power stage rotary valve is precisely controlled by the rotation angle of the pilot valve core, achieving high-precision mechanical rotation angle feedback. A single-rotor valve with a dual-cycle symmetrical design achieves the function of a three-position four-way solenoid directional valve. An axial and radial bidirectional hydrostatic support design achieves bidirectional shaft diameter sealing wear compensation and lubrication, realizing high efficiency, low drive power, high stability, high precision control of the hydraulic valve, and applicability to various viscosity media.

[0005] Specifically, the present invention provides a two-stage rotary servo valve, which includes an integrated motor assembly, a pilot stage valve core assembly, a power stage valve core assembly, and a flow distribution valve body assembly;

[0006] The integrated motor assembly is used to drive the pilot-stage valve core assembly to rotate, and the pilot-stage valve core assembly is used to drive the power-stage valve core assembly to rotate under the drive of the integrated motor assembly, thereby achieving mechanical angle feedback.

[0007] The pilot valve core assembly includes a pilot valve core, a floating side plate, a first sealing ring, a second sealing ring, and a third sealing ring. The pilot valve core is connected to the motor rotation shaft of the integrated motor assembly. The first mounting surface of the floating side plate is connected to the second mounting surface of the motor housing of the integrated motor assembly. The first sealing ring, the second sealing ring, and the third sealing ring are respectively placed in three sealing grooves.

[0008] The power stage valve core assembly includes a power stage valve sleeve, a power stage valve core, rotary valve blades, a rotary valve center spring, a first floating blade, a second floating blade, a first fixed blade, and a second fixed blade. The first mounting surface of the power stage valve sleeve is connected to the second mounting surface of the floating side plate. The inner circumference of the power stage valve sleeve is connected to the power stage valve core. Eight rotary valve blades are evenly distributed on the power stage valve core. The inner circumference of the power stage valve core is connected to the first and second floating blades, which are at 180° intervals, and to the first and second fixed blades, which are also at 180° intervals. The second fixed blade, the first floating blade, the floating side plate, and the... The power stage valve sleeve together constitutes the first pilot fluid cavity; the first fixed vane, the second floating vane, the floating side plate, and the power stage valve sleeve together constitute the second pilot fluid cavity; the first floating vane, the first fixed vane, the floating side plate, and the power stage valve sleeve together constitute the third pilot fluid cavity; the second floating vane, the second fixed vane, the floating side plate, and the power stage valve sleeve together constitute the fourth pilot fluid cavity; the floating side plate, the power stage valve sleeve, the power stage valve core, and eight rotary valve vanes constitute four power fluid cavities, namely the first power fluid cavity, the second power fluid cavity, the third power fluid cavity, and the fourth power fluid cavity;

[0009] The distribution valve body assembly includes a T-port distribution valve body, an A-port distribution valve body, a B-port distribution valve body, a distribution end cap, an A-port pipe connector, a B-port pipe connector, and a T-port pipe connector; the first mounting surface of the T-port distribution valve body is connected to the second mounting surface of the power stage valve sleeve, the first mounting surface of the A-port distribution valve body is connected to the second mounting surface of the T-port distribution valve body, the first mounting surface of the B-port distribution valve body is connected to the second mounting surface of the A-port distribution valve body, the first mounting surface of the distribution end cap is connected to the second mounting surface of the B-port distribution valve body, and the A-port pipe connector, B-port pipe connector, and T-port pipe connector are all mounted on the second mounting surface of the distribution end cap;

[0010] When the motor shaft of the integrated motor assembly rotates, it drives the pilot valve core to rotate. The fluid medium enters the first central hole of the pilot valve core through the P-port pipe joint, the P-port distribution groove, the first sinking distribution groove of the pilot valve core, and the first drainage hole of the pilot valve core, and then enters the first drainage groove of the pilot valve core; at the same time, the fluid medium enters the power stage fluid chamber through the P-port pipe joint and the P-port distribution groove.

[0011] When the pilot valve core rotates, it drives the power valve core to rotate. The first high-pressure fluid medium flowing into the power valve core from the P port connector flows through the A port distribution groove of the A port distribution valve body to the A port connector. The second low-pressure fluid medium flowing into the B port connector enters the power fluid chamber through the B port distribution groove of the B port distribution valve body, and then flows into the T port distribution groove and enters the T port distribution valve body. After that, one low-pressure fluid medium flows out of the T port connector, and the other low-pressure fluid medium sequentially passes through the second sinking distribution groove of the pilot valve core, the second drain hole of the pilot valve core, and enters the second central hole of the pilot valve core, and then enters the second drain groove of the pilot valve core and flows into the pilot valve core.

[0012] After receiving an electrical signal, the mechanical feedback two-stage rotary servo valve rotates the motor shaft of the integrated motor assembly, which in turn drives the pilot valve core to rotate. The pilot valve core rotates so that the fluid medium flows into the pilot fluid chamber through the drainage holes of the floating blades, driving the power valve core to rotate. If the rotation angle of the power valve core is too large, the high-pressure chamber and the low-pressure chamber are switched. The pressure difference is used to drive the first and second floating blades to rotate the power valve core through the slots until the pilot valve core's first and second drainage slots are adjusted to their initial positions relative to the drainage holes of the floating blades.

[0013] Preferably, the integrated motor assembly includes a motor rotating shaft, a motor rotor, a motor stator, a motor coil, a motor housing, a first valve core retaining ring, a second valve core retaining ring, and a P-port pipe connector; the motor rotor includes a first motor rotor and a second motor rotor, the inner circumference of the motor rotor is fixed to the motor rotating shaft by the first valve core retaining ring and the second valve core retaining ring, the outer circumference of the motor rotor is connected to the motor stator, the motor coil is disposed inside the motor stator, and the P-port pipe connector is disposed inside the motor housing;

[0014] When the integrated motor assembly is working, it supplies power to the coil through the motor terminal. When there is current between the stator and rotor assemblies of the motor, a magnetic field is generated, which causes the rotor assembly to start moving. The rotor assembly is connected to the motor shaft through a spline, thereby driving the motor shaft to rotate.

[0015] Preferably, the motor terminal is mounted on the first mounting surface of the motor end cover, and the motor rotating shaft is fixed in the end cover opening of the second mounting surface of the motor end cover through the first rotary valve bearing and the first bearing retaining ring. The first rotary valve bearing, the first bearing retaining ring, the first mounting surface of the motor housing, and the second mounting surface of the motor end cover are connected.

[0016] Preferably, the pilot stage valve core assembly further includes a first plug and a second plug, wherein the first plug is placed in the first threaded hole of the fourth center hole of the pilot stage valve core, and the second plug is placed in the second threaded hole of the fourth center hole of the pilot stage valve core.

[0017] Preferably, the pilot valve core assembly further includes a second rotary valve bearing, a third rotary valve bearing, a second bearing retaining ring, a third valve core retaining ring, and a fourth valve core retaining ring; the second rotary valve bearing is axially positioned on the motor housing by the second bearing retaining ring and fixed on the pilot valve core by the third and fourth valve core retaining rings, and the third rotary valve bearing is axially positioned and fixed between the pilot valve core and the A-port distribution valve body by a sleeve.

[0018] Preferably, a rotary valve center spring is installed on each rotary valve blade.

[0019] Preferably, the pilot valve core assembly is further provided with a sleeve.

[0020] On the other hand, the present invention also provides a two-stage rotary valve servo valve control method, which includes the following steps:

[0021] S1, Input control commands;

[0022] S2. The integrated motor assembly drives the pilot stage valve core assembly to rotate ±α according to the control command, and the pilot stage valve core assembly further drives the power stage valve core assembly to rotate.

[0023] S3. When the rotation angle of the power stage valve core is too large, by switching the high pressure chamber and the low pressure chamber, under the action of the pressure difference, the first floating vane and the second floating vane drive the power stage valve core to rotate in the opposite direction through the slot until they are adjusted to the initial position of the first and second flow channels of the pilot stage valve core relative to the flow holes of the floating vane, so that the power stage valve core rotates ±α° with the pilot stage valve core.

[0024] Preferably, when the control command is to distribute current between PA and BT:

[0025] The input command rotates the motor by -α°. The electrical control signal generates a magnetic field between the motor stator and the motor rotor through the motor coil, and the interaction generates torque to drive the motor rotor to rotate by -α°, which in turn drives the motor shaft to rotate by -α°, which in turn drives the pilot valve core to rotate by -α°.

[0026] The first pressure oil enters the first sinking distribution groove of the pilot stage valve core through the P-port pipe joint, the P-port distribution groove, and the second P-port distribution groove, and then enters the first central hole of the pilot stage valve core through the first guide hole of the pilot stage valve core, and further enters the first guide groove of the pilot stage valve core. At this time, the pilot stage valve core rotates by -α° to make the first guide groove of the pilot stage valve core connect with the first guide hole of the first floating vane and the first guide hole of the second floating vane. The high-pressure fluid medium in the first guide groove of the pilot stage valve core enters the third pilot stage valve core through the first guide hole of the first floating vane and the first guide hole of the second floating vane. The fluid chamber and the fourth pilot fluid chamber; the second hydraulic oil enters the second central hole of the pilot valve core through the second sinking distribution groove and the second guide hole of the pilot valve core via the T-port pipe joint, and then enters the second guide groove of the pilot valve core. At this time, the pilot valve core rotates -α°, and the second guide groove of the pilot valve core is connected with the fourth guide hole of the first floating blade and the fourth guide hole of the second floating blade. The low-pressure fluid medium in the second guide groove of the pilot valve core enters the first pilot fluid chamber and the second pilot fluid chamber through the fourth guide hole of the first floating blade and the fourth guide hole of the second floating blade.

[0027] When the third and fourth pilot fluid chambers are high-pressure oil chambers, and the first and second pilot fluid chambers are low-pressure oil chambers, the first and second floating vanes drive the power stage valve core to rotate through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chambers.

[0028] Driven by the pilot valve core, the first hydraulic oil enters the first power fluid chamber and the third power fluid chamber through the P-port pipe connector, the P-port distribution groove and the second P-port distribution groove, and then is output to the A-port pipe connector through the A-port first distribution groove and the A-port second distribution groove of the A-port distribution valve body, realizing the flow of PA; at the same time, the second hydraulic oil flows in through the B-port pipe connector, flows through the B-port first distribution groove and the B-port second distribution groove of the B-port distribution valve body, enters the second power fluid chamber and the fourth power fluid chamber, then flows into the T-port first distribution groove, enters the T-port distribution valve body, and then flows out to the T-port pipe connector, realizing the flow of BT;

[0029] If the power stage valve core rotates too much, the first guide groove of the pilot stage valve core will rotate to connect with the second guide hole of the first floating vane and the second guide hole of the second floating vane, and the second guide groove of the pilot stage valve core will connect with the third guide hole of the first floating vane and the third guide hole of the second floating vane. At this time, the third pilot fluid chamber and the fourth pilot fluid chamber become low-pressure oil chambers, and the first pilot fluid chamber and the second pilot fluid chamber become high-pressure oil chambers. Under the action of pressure difference, the first floating vane and the second floating vane drive the power stage valve core to rotate in the opposite direction through the slot until they are adjusted to the initial position of the first guide groove and the second guide groove of the pilot stage valve core relative to the guide holes of the floating vane, so that the power stage valve core rotates -α° with the pilot stage valve core.

[0030] Preferably, when the control command is to distribute current between PB and AT connections:

[0031] The input command rotates by +α°. The electrical control signal generates a magnetic field between the motor stator and the motor rotor through the motor coil, and the interaction generates torque to drive the motor rotor to rotate by +α°, drive the motor shaft to rotate by +α°, and then drive the pilot valve core to rotate by +α°.

[0032] The first pressure oil enters the first sinking distribution groove of the pilot valve core through the P-port pipe joint, the P-port distribution groove and the second P-port distribution groove, and enters the first central hole of the pilot valve core through the first guide hole of the pilot valve core, and then enters the first guide groove of the pilot valve core. At this time, the pilot valve core rotates by +α° to make the first guide groove of the pilot valve core rotate to connect with the second guide hole of the first floating blade and the second guide hole of the second floating blade. The high pressure fluid medium in the first guide groove of the pilot valve core enters the first pilot fluid cavity and the second pilot fluid cavity through the second guide hole of the first floating blade and the second guide hole of the second floating blade.

[0033] The second hydraulic oil enters the second central hole of the pilot valve core through the second sinking distribution groove and the second guide hole of the pilot valve core via the T-port pipe joint, and then enters the second guide groove of the pilot valve core. At this time, the pilot valve core rotates +α°, and the second guide groove of the pilot valve core connects with the third guide hole of the first floating vane and the third guide hole of the second floating vane. The low-pressure fluid medium in the second guide groove of the pilot valve core enters the third pilot fluid chamber and the fourth pilot fluid chamber through the third guide hole of the first floating vane and the third guide hole of the second floating vane.

[0034] When the third and fourth pilot fluid chambers are low-pressure oil chambers, and the first and second pilot fluid chambers are high-pressure oil chambers, the first and second floating vanes drive the power stage valve core to rotate through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chambers.

[0035] Driven by the pilot valve core, the first hydraulic oil enters the second power fluid chamber and the fourth power fluid chamber through the P-port pipe connector, the P-port distribution groove and the second P-port distribution groove, flows into the T-port first distribution groove and the T-port first distribution groove into the T-port distribution valve body, and then flows out to the T-port pipe connector, realizing the flow of PB; at the same time, the second hydraulic oil flows in through the B-port pipe connector, flows through the B-port first distribution groove and the B-port second distribution groove of the B-port distribution valve body, enters the first power fluid chamber and the third power fluid chamber, and is output to the A-port pipe connector through the A-port first distribution groove and the A-port second distribution groove of the A-port distribution valve body, realizing the flow of AT;

[0036] If the power stage valve core rotates too much, causing the first guide groove of the pilot stage valve core to rotate to connect with the first guide hole of the first floating vane and the first guide hole of the second floating vane, and the second guide groove of the pilot stage valve core to connect with the fourth guide hole of the first floating vane and the fourth guide hole of the second floating vane, then the third and fourth pilot fluid chambers become high-pressure oil chambers, and the first and second pilot fluid chambers become low-pressure oil chambers. Under the action of the pressure difference, the first and second floating vanes drive the power stage valve core to rotate in the opposite direction through the slots until they are adjusted to the initial positions of the first and second guide grooves of the pilot stage valve core relative to the guide holes of the floating vanes, thus achieving a final rotation of +α° with the pilot stage valve core.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] (1) This invention proposes a mechanical feedback two-stage rotary servo valve. The servo valve adopts a modular design, and sequentially integrates a motor assembly, a pilot stage valve core assembly, a power stage valve core assembly, and a flow distribution valve body assembly. It adopts a rotary valve core structure, and the flow distribution is a planar flow distribution method. The servo valve feedback method is mechanical rotation feedback through the valve core rotation angle. The valve body has low processing difficulty, faster response speed, and more accurate feedback, and can be applied to applications with higher pressure and higher flow.

[0039] (2) The power valve core assembly of the present invention uses a single rotary valve to realize the function of a three-position four-way directional valve. The power rotary valve adopts a double-cycle symmetrical design and adopts axial and radial bidirectional hydrostatic support, thereby improving the stress state of the valve core, reducing the vibration of the valve core, and improving the stability of the valve core. Secondly, the hydrostatic support on both sides of the rotary valve shaft can effectively prevent fluid medium leakage and valve core wear, and ensure the sealing between the valve core and the valve seat. In addition, the hydrostatic support can reduce the friction between the valve core and the valve seat, thereby reducing the dynamic friction of the valve core, improving the response speed of the valve core, and reducing the driving torque and driving cost.

[0040] (3) This invention proposes for the first time a control method that allows the power stage valve core to follow the rotation angle of the pilot stage valve core, effectively overcoming problems such as large frictional torque caused by bidirectional hydrostatic support. The proposed control correction method is as follows: if the rotation angle of the power stage valve core is too large, the first and second guide grooves of the pilot stage valve core are reversed with the floating vane holes, realizing the interchange of the high-pressure and low-pressure oil chamber positions of the first, second, third, and fourth pilot fluid chambers. Under the action of the pressure difference, the rotation angle of the main valve core is adjusted to be consistent with the rotation angle of the pilot stage valve core, thus achieving high-precision rotation angle following control of the power stage valve core.

[0041] (4) The structure of this invention has a wide range of applications and can be applied to a variety of fields. The servo valve has a simple structure and small size, and has great innovation and promotion value, with a bright application prospect. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the mechanical feedback two-stage rotary valve servo valve of the present invention;

[0043] Figure 2 This is a cross-sectional view of the mechanical feedback two-stage rotary valve servo valve of the present invention.

[0044] Figure 3 This is a radial sectional view of the motor housing of the present invention;

[0045] Figure 4 This is a schematic diagram of the structure of the floating side plate of the present invention;

[0046] Figure 5 This is a schematic diagram of the pilot stage valve core of the present invention;

[0047] Figure 6 This is a schematic diagram of the power stage valve core of the present invention;

[0048] Figure 7a This is a radial cross-sectional view of the first drainage hole of the floating blade of the present invention; Figure 7b This is a radial cross-sectional view of the second drainage hole of the floating blade of the present invention; Figure 7c This is a radial cross-sectional view of the third drainage hole of the floating blade of the present invention; Figure 7d This is a radial cross-sectional view of the fourth drainage hole of the floating blade of the present invention;

[0049] Figure 8 This is a radial sectional view of the T-port flow distribution valve body of the present invention;

[0050] Figure 9 This is a radial sectional view of the A-port flow distribution valve body of the present invention;

[0051] Figure 10 This is a radial sectional view of the B-port flow distribution valve body of the present invention;

[0052] Figure 11 This is a schematic diagram of the structure of the second mounting surface of the distribution end cap of the present invention;

[0053] Figure 12 This is a hydraulic working principle diagram of a mechanical feedback two-stage rotary servo valve and its control method according to the present invention.

[0054] The main reference numerals are as follows:

[0055] 1-Motor wiring port, 2-Motor end cover, 3-Motor rotating shaft, 4-Motor first rotor, 5-Motor second rotor, 6-Motor stator, 7-Motor coil, 8-Motor housing, 9-Pilot valve core, 901-Second threaded hole of the fourth center hole of the pilot valve core, 902-Second recessed distribution groove of the pilot valve core, 903-Second drainage groove of the pilot valve core, 904-First drainage groove of the pilot valve core, 905-First recessed distribution groove of the pilot valve core, 906-Third recessed distribution groove of the pilot valve core, 907-Fourth recessed distribution groove of the pilot valve core, 908-First threaded hole of the fourth center hole of the pilot valve core, 909-Second drainage hole of the pilot valve core, 9 10-Pilot stage valve core second center hole, 911-Pilot stage valve core first drain hole, 912-Pilot stage valve core first center hole, 10-First plug, 11-Second plug, 12-Floating side plate, 13-Power stage valve sleeve, 14-Power stage valve core, 15-Rotating valve vane, 16-Rotating valve center spring, 17-First floating vane, 1701-First floating vane first drain hole, 1702-First floating vane second drain hole, 1703-First floating vane third drain hole, 1704-First floating vane fourth drain hole, 18-First fixed vane, 19-T-port distribution valve body, 20-A-port distribution valve body, 21-B-port distribution valve body, 22-Distribution... Flow end cap, 2301-First rotary valve bearing, 2302-Second rotary valve bearing, 2303-Third rotary valve bearing, 2401-First bearing retaining ring, 2402-Second bearing retaining ring, 2501-First valve core retaining ring, 2502-Second valve core retaining ring, 2503-Third valve core retaining ring, 2504-Fourth valve core retaining ring, 2601-First sealing ring, 2602-Second sealing ring, 2603-Third sealing ring, 27-First pilot fluid cavity, 28-First power fluid cavity, 29-First distribution groove at port B, 30-First distribution groove at port A, 31-Second distribution groove at port B, 32-Second distribution groove at port A, 33-First distribution groove at port T, 34- 35-T-port second distribution channel, 36-B-port pipe connector, 37-T-port pipe connector, 38-first P-port distribution channel, 39-second P-port distribution channel, 40-sleeve, 41-A-port pipe connector, 42-second pilot fluid cavity, 43-third pilot fluid cavity, 44-fourth pilot fluid cavity, 45-second floating blade, 4501-first drainage hole of second floating blade, 4502-second drainage hole of second floating blade, 4503-third drainage hole of second floating blade, 4504-fourth drainage hole of second floating blade, 46-second fixed blade, 47-second power fluid cavity, 48-third power fluid cavity, 49-fourth power fluid cavity. Detailed Implementation

[0056] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0057] This invention provides a mechanical feedback two-stage rotary servo valve, wherein the mechanical feedback two-stage rotary servo valve is as follows: Figures 1 to 12 As shown, the mechanical feedback two-stage rotary servo valve has an integrated motor assembly, a pilot stage valve core assembly, a power stage valve core assembly, and a flow distribution valve body assembly arranged sequentially along the central axis of the valve body.

[0058] The integrated motor assembly is used to drive the pilot valve core rotation, including motor terminal 1, motor end cover 2, motor rotating shaft 3, motor first rotor 4, motor second rotor 5, motor stator 6, motor coil 7, motor housing 8, first rotary valve bearing 2301, first bearing retaining ring 2401, first valve core retaining ring 2501, second valve core retaining ring 2502, and P-port pipe connector 37. The motor terminal 1 is installed on the first mounting surface of the motor end cover 2. The motor rotating shaft 3 is fixed inside the end cover opening of the second mounting surface of the motor end cover 2 by the first rotary valve bearing 2301 and the first bearing retainer 2401. The first rotor 4 and the second rotor 5 of the motor form the motor rotor. The inner ring of the motor rotor is fixed on the motor rotating shaft 3 by the first valve core retainer 2501 and the second valve core retainer 2502 respectively. The outer circumference of the motor rotor is installed concentrically with the motor stator 6. The motor coil 7 is located inside the motor stator 6. The first mounting surface of the motor housing 8 is connected to the second mounting surface of the motor end cover 2. The P-port pipe connector 37 is fixed to the outside of the motor housing 8 by bolts.

[0059] When the integrated motor assembly is working, it supplies power to the coil 7 through the motor terminal 1. When there is current between the motor stator 6 and the motor rotor, a magnetic field is generated. Under the interaction of the electromagnetic fields, a torque is generated, which causes the motor rotor to start moving. The motor rotor is connected to the motor rotating shaft 3 through a spline, thereby driving the motor rotating shaft 3 to rotate.

[0060] The pilot-stage valve core assembly is used to drive the power stage valve core 14 to rotate, achieving high-precision mechanical angle feedback. It includes a pilot-stage valve core 9, a floating side plate 12, a first plug 10, a second plug 11, a second rotary valve bearing 2302, a third rotary valve bearing 2303, a second bearing retaining ring 2402, a third valve core retaining ring 2503, a fourth valve core retaining ring 2504, a first sealing ring 2601, a second sealing ring 2602, a third sealing ring 2603, and a sleeve 40. The second fixed blade 46 and the first floating... The blade 17, the floating side plate 12, and the power stage valve sleeve 13 together form the first pilot fluid cavity 27. The first fixed blade 18, the second floating blade 45, the floating side plate 12, and the power stage valve sleeve 13 together form the second pilot fluid cavity 42. The first floating blade 17, the first fixed blade 18, the floating side plate 12, and the power stage valve sleeve 13 together form the third pilot fluid cavity 43. The second floating blade 45, the second fixed blade 46, the floating side plate 12, and the power stage valve sleeve 13 together form the fourth pilot fluid cavity 44. The pilot valve core 9 is connected to the motor rotating shaft 3 via a spline. The first mounting surface of the floating side plate 12 is connected to the second mounting surface of the motor housing 8. The first screw plug 10 is placed in the first threaded hole 908 of the fourth center hole of the pilot valve core. The second screw plug 11 is placed in the second threaded hole 901 of the fourth center hole of the pilot valve core. The second rotary valve bearing 2302 is axially positioned on the motor housing 8 via the second bearing retainer 2402. It is axially positioned and fixed on the pilot valve core 9 via the third valve core retainer 2503 and the fourth valve core retainer 2504. The first sealing ring 2601, the second sealing ring 2602, and the third sealing ring 2603 are placed in the three sealing grooves of the pilot valve core 9. The third rotary valve bearing 2303 is axially positioned and fixed between the pilot valve core 9 and the A-port distribution valve body 20 via the sleeve 40.

[0061] The power stage valve core assembly includes a power stage valve sleeve 13, a power stage valve core 14, a rotary valve vane 15, a rotary valve center spring 16, a first floating vane 17, a first fixed vane 18, a second floating vane 45, and a second fixed vane 46. The first mounting surface of the power stage valve sleeve 13 is connected to the second mounting surface of the floating side plate 12, and the inner circumference is connected to the power stage valve core 14. Eight rotary valve blades 15 are distributed on the power stage valve core 14. Each rotary valve blade 15 is equipped with a rotary valve center spring 16. The inner circumference of the power stage valve core 14 is connected to two floating blades 17 and 45 and two fixed blades 18 and 46 that are 180° apart. The rotary valve blades 15, the rotary valve center spring 16 and the power stage valve core 14 form the radial hydrostatic support volume cavity of the power stage valve core 14. The floating side plate 12, the power stage valve sleeve 13, the power stage valve core 14 and the eight rotary valve blades 15 respectively form the first power fluid cavity 28, the second power fluid cavity 47, the third power fluid cavity 48 and the fourth power fluid cavity 49.

[0062] The distribution valve body assembly includes a T-port distribution valve body 19, an A-port distribution valve body 20, a B-port distribution valve body 21, a distribution end cap 22, an A-port pipe connector 41, a B-port pipe connector 35, and a T-port pipe connector 36. The first mounting surface of the T-port distribution valve body 19 is connected to the second mounting surface of the power stage valve sleeve 13. The first mounting surface of the A-port distribution valve body 20 is connected to the second mounting surface of the T-port distribution valve body 19. The first mounting surface of the B-port distribution valve body 21 is connected to the second mounting surface of the A-port distribution valve body 20. The first mounting surface of the distribution end cap 22 is connected to the second mounting surface of the B-port distribution valve body 21. The A-port pipe connector 41, the B-port pipe connector 35, and the T-port pipe connector 36 are mounted on the second mounting surface of the distribution end cap 22.

[0063] The pilot valve core 9 in the pilot valve core assembly is connected to the motor rotating shaft 3 via a spline. When the motor rotating shaft 3 rotates, it drives the pilot valve core 9 to rotate. At the same time, the fluid medium enters the first sinking distribution groove 905, the first guide hole 911, and the first center hole 912 of the pilot valve core sequentially through the P-port pipe joint 37, the P-port distribution groove 38, and the second P-port distribution groove 39, and then enters the first guide groove 904 of the pilot valve core. The second pressure oil is introduced through the T-port second distribution groove 34, flows sequentially to the second sinking distribution groove 902, the second guide hole 909 of the pilot valve core, and enters the second center hole 910 of the pilot valve core, and then enters the second guide groove 903 of the pilot valve core and flows into the corresponding pilot fluid chamber. When the pilot valve core 9 rotates under the drive of the integrated motor (currently analyzed as counterclockwise rotation; clockwise rotation is similar and will not be described here), the first guide groove 904 of the pilot valve core rotates to connect with the first guide hole 1701 of the first floating blade and the first guide hole 4501 of the second floating blade. At this point, the high-pressure fluid medium in the first guide groove 904 of the pilot valve core enters the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 through the first guide hole 1701 of the first floating blade 17 and the first guide hole 4501 of the second floating blade 45. Simultaneously, the second guide groove 903 in the pilot valve core rotates to connect with the fourth guide hole of the first floating blade. The first floating vane 1704 and the second floating vane 4504 are connected. The low-pressure fluid medium in the second flow channel 903 of the pilot stage valve core enters the first pilot fluid chamber 27 and the second pilot fluid chamber 42 through the first floating vane 4504 and the second floating vane 4504. At this time, the first floating vane 17 and the second floating vane 45, under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chamber, push the power stage valve core 14 to rotate counterclockwise through the slot until the first flow channel 904 of the pilot stage valve core separates from the first floating vane 1701 and the second floating vane 4501. In summary, the power stage valve core 14 is controlled to follow the angle of the pilot stage valve core 9.

[0064] The function of each valve body in the distribution valve assembly is to distribute flow to each pipe interface as the power stage valve core 14 rotates. When the pilot stage valve core 9 rotates counterclockwise, it drives the power stage valve core 14 to rotate counterclockwise (the analysis is similar for the pilot valve's counterclockwise rotation, and clockwise rotation will not be described here). The P-port pipe connector 37 flows into the power stage valve core 14, and through the P-port distribution groove 38 and the second P-port distribution groove 39, flows to the first power fluid chamber 28 and the third power fluid chamber 28 of the power stage valve core 14, respectively. The fluid flows from the A-port first distribution channel 30 and the A-port second distribution channel 32 of the A-port distribution valve body 20 to the A-port pipe joint 41. The low-pressure fluid medium flows in through the B-port pipe joint 35, passes through the B-port first distribution channel 29 and the B-port second distribution channel 31 of the B-port distribution valve body 21, enters the second power fluid chamber 47 and the fourth power fluid chamber 49, and then flows into the T-port first distribution channel 33 and the T-port first distribution channel 34, enters the T-port distribution valve body 19, and exits through the T-port pipe joint 36. In summary, this achieves PA and BT connection control of the rotary valve.

[0065] After receiving an electrical signal, the two-stage rotary servo valve with mechanical feedback first generates a magnetic field between the motor stator 6 and the motor rotors 4 and 5 through the motor coil 7. The interaction of these magnetic fields generates torque, driving the motor rotor to rotate. This, in turn, drives the motor shaft 3 to rotate. The motor shaft 3, connected by a spline, then drives the pilot valve core 9 to rotate. The rotation of the pilot valve core 9 allows the high-pressure fluid medium from the P-port connector 37 and the low-pressure fluid medium from the T-port connector 36 to flow into the pilot fluid chamber through the drainage holes of the floating vanes 17 and 45. The pressure difference then drives the power valve core 14 to rotate, thus achieving two-stage mechanical rotational feedback. The integrated motor controls the rotation angle, which is the rotation angle of the pilot valve core 9, and ultimately controls the final rotation angle of the power valve core 14, thereby achieving flow and pressure control at the rotary valve orifice.

[0066] In summary, a two-stage rotary valve enables combined on / off control of pressure port P, pressure port T, hydraulic port A, and hydraulic port B. When the valve core rotates counterclockwise, pressure port P connects to hydraulic port A, and hydraulic port B connects to pressure port T. When rotated clockwise, pressure port P connects to hydraulic port B, and pressure port T connects to hydraulic port A.

[0067] On the other hand, the present invention provides a control method for a two-stage rotary servo valve, which includes the following steps:

[0068] S1, Input control commands;

[0069] S2. The integrated motor assembly drives the pilot stage valve core assembly to rotate ±α according to the control command, and the pilot stage valve core assembly further drives the power stage valve core assembly to rotate.

[0070] S3. When the rotation angle of the power stage valve core is too large, by switching the high-pressure chamber and the low-pressure chamber, under the action of the pressure difference, the first and second floating vanes drive the power stage valve core to rotate in opposite directions through the slots until they are adjusted to the initial positions of the first and second flow channels of the pilot stage valve core relative to the flow holes of the floating vanes, so that the power stage valve core rotates ±α° with the pilot stage valve core. A rotation of +α° of the pilot stage valve core performs an opening action or enhances the flow distribution between PB and AT; a rotation of -α° of the pilot stage valve core performs a closing action or enhances the flow distribution between PA and BT.

[0071] The mechanical feedback two-stage rotary servo valve and its control method in this embodiment are described below. The specific control method is as follows:

[0072] When the control command is to connect PA and BT for flow distribution: rotate counterclockwise by α°, i.e., rotate by -α° (at which time the flow rate is XL / min) for detailed analysis (the relationship between the rotation angle and the flow rate is determined by the specific size and structure of the rotary valve, and no limitation or constraint is imposed here).

[0073] The pilot valve rotation angle control process is as follows: The input command to rotate counterclockwise by α° is generated by the electric control signal through the motor coil 7 between the motor stator 6 and the motor rotors 4 and 5, and the interaction generates torque to drive the motor rotor to rotate counterclockwise by α°. The motor rotor is connected to the motor rotating shaft 3 through a spline, which in turn drives the motor rotating shaft 3 to rotate counterclockwise by α°. The motor rotating shaft 3 is connected to the pilot valve core 9 through a spline, which in turn drives the pilot valve core 9 to rotate counterclockwise by α°.

[0074] The high-pressure chamber of the pilot valve is controlled as follows: the first pressure oil enters the first sinking distribution groove 905 of the pilot valve core through the P-port pipe joint 37, the P-port distribution groove 38 and the second P-port distribution groove 39, and enters the first central hole 912 of the pilot valve core through the first guide hole 911 of the pilot valve core, and then enters the first guide groove 904 of the pilot valve core. At this time, the pilot valve core 9 rotates counterclockwise by α° to make the first guide groove 904 of the pilot valve core rotate to connect with the first guide hole 1701 of the first floating blade and the first guide hole 4501 of the second floating blade. The high-pressure fluid medium in the first guide groove 904 of the pilot valve core enters the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 through the first guide hole 1701 of the first floating blade 17 and the first guide hole 4501 of the second floating blade 45.

[0075] The low-pressure chamber of the pilot valve is controlled as follows: The second hydraulic oil enters the second central hole 910 of the pilot valve core through the second sinking distribution groove 902 and the second guide hole 909 of the pilot valve core via the T-port pipe joint 36, and then enters the second guide groove 903 of the pilot valve core. At this time, the pilot valve core 9 rotates counterclockwise by α°, and the second guide groove 903 of the pilot valve core is connected with the fourth guide hole 1704 of the first floating vane and the fourth guide hole 4504 of the second floating vane. The low-pressure fluid medium in the second guide groove 903 of the pilot valve core enters the first pilot fluid chamber 27 and the second pilot fluid chamber 42 through the fourth guide hole 1704 of the first floating vane and the fourth guide hole 4504 of the second floating vane.

[0076] The pilot valve rotation process is as follows: when the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 are high-pressure oil chambers, and the first pilot fluid chamber 27 and the second pilot fluid chamber 42 are low-pressure oil chambers, the first floating vane 17 and the second floating vane 45 drive the power stage valve core 14 to rotate counterclockwise through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chamber.

[0077] The working process of the power stage valve core is as follows: Under the drive of the pilot stage valve core 9, the first hydraulic oil enters the first power fluid chamber 28 and the third power fluid chamber 48 through the P port pipe joint 37, the P port distribution groove 38 and the second P port distribution groove 39, and then is output to the A port pipe joint 41 through the A port first distribution groove 30 and the A port second distribution groove 32 of the A port distribution valve body 20, realizing the flow of PA; at the same time, the second hydraulic oil flows in through the B port pipe joint 35, passes through the B port first distribution groove 29 and the B port second distribution groove 31 of the B port distribution valve body 21 and enters the second power fluid chamber 47 and the fourth power fluid chamber 49, and then flows into the T port first distribution groove 33 and the T port first distribution groove 34 and enters the T port distribution valve body 19, and then flows out to the T port pipe joint 36, realizing the flow of BT.

[0078] The control angle correction process is as follows: If the power stage valve core rotates too counterclockwise, the first guide groove 904 of the pilot stage valve core will rotate to connect with the second guide hole 1702 of the first floating blade and the second guide hole 4502 of the second floating blade, and the second guide groove 903 of the pilot stage valve core will connect with the third guide hole 1703 of the first floating blade and the third guide hole 4503 of the second floating blade. At this time, the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 become low-pressure oil chambers, and the first pilot fluid chamber 27 and the second pilot fluid chamber 42 become high-pressure oil chambers. The positions of the high-pressure and low-pressure oil chambers are interchanged. Under the action of the pressure difference, the first floating blade 17 and the second floating blade 45 drive the power stage valve core 14 to rotate clockwise through the slot until it is adjusted to the initial position of the first guide groove 904 and the second guide groove 903 of the pilot stage valve core relative to the guide holes of the floating blades. This means that the power stage valve core 14 eventually rotates counterclockwise by α° with the pilot stage valve core 9. For example, the motor first drives the pilot valve core to rotate 5 degrees clockwise. The pilot valve core connects the vane drain hole, and the oil enters the high-pressure chamber to drive the power stage valve core to rotate until it returns to the position where the drain hole is not connected. This is equivalent to the power stage valve core also rotating 5 degrees clockwise, returning to the initial position relative to each drain hole, thereby achieving the purpose of adjusting the target angle.

[0079] When the control command is to distribute the flow between PB and AT: a detailed analysis is performed by rotating clockwise by α°, i.e., rotating by +α° (at which point the flow rate is XL / min) (the relationship between the rotation angle and the flow rate is determined by the specific dimensions and structure of the rotary valve, and no limitations are imposed here).

[0080] The pilot valve rotation angle control process is as follows: The input command to rotate clockwise by α° is an electrical control signal that generates a magnetic field between the motor stator 6 and the motor rotors 4 and 5 through the motor coil 7. The magnetic field interacts with the motor coil to generate torque, which drives the motor rotor to rotate clockwise by α°. The motor rotor is connected to the motor rotating shaft 3 through a spline, which in turn drives the motor rotating shaft 3 to rotate clockwise by α°. The motor rotating shaft 3 is connected to the pilot valve core 9 through a spline, which in turn drives the pilot valve core 9 to rotate clockwise by α°.

[0081] The high-pressure chamber of the pilot valve is controlled as follows: The first pressure oil enters the first sinking distribution groove 905 of the pilot valve core through the P-port pipe joint 37, the P-port distribution groove 38 and the second P-port distribution groove 39, and enters the first central hole 912 of the pilot valve core through the first guide hole 911 of the pilot valve core, and then enters the first guide groove 904 of the pilot valve core. At this time, the pilot valve core 9 rotates clockwise by α° to make the first guide groove 904 of the pilot valve core rotate to connect with the second guide hole 1702 of the first floating blade and the second guide hole 4502 of the second floating blade. The high-pressure fluid medium in the first guide groove 904 of the pilot valve core enters the first pilot fluid chamber 27 and the second pilot fluid chamber 42 through the second guide hole 1702 of the first floating blade and the second guide hole 4502 of the second floating blade.

[0082] The low-pressure chamber of the pilot valve is controlled as follows: The second hydraulic oil enters the second central hole 910 of the pilot valve core through the second sinking distribution groove 902 and the second guide hole 909 of the pilot valve core via the T-port pipe joint 36, and then enters the second guide groove 903 of the pilot valve core. At this time, the pilot valve core 9 rotates clockwise by α°, and the second guide groove 903 of the pilot valve core is connected with the third guide hole 1703 of the first floating vane and the third guide hole 4503 of the second floating vane. The low-pressure fluid medium in the second guide groove 903 of the pilot valve core enters the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 through the third guide hole 1703 of the first floating vane and the third guide hole 4503 of the second floating vane.

[0083] The pilot valve rotation process is as follows: when the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 are low-pressure oil chambers, and the first pilot fluid chamber 27 and the second pilot fluid chamber 42 are high-pressure oil chambers, the first floating vane 17 and the second floating vane 45 drive the power stage valve core 14 to rotate clockwise through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chamber.

[0084] The working process of the power stage valve core is as follows: Under the drive of the pilot stage valve core 9, the first hydraulic oil enters the second power fluid chamber 47 and the fourth power fluid chamber 49 through the P port pipe joint 37, the P port distribution groove 38 and the second P port distribution groove 39, flows into the T port first distribution groove 33 and the T port first distribution groove 34 and enters the T port distribution valve body 19, and then flows out to the T port pipe joint 36 to realize the flow of PB; at the same time, the second hydraulic oil flows in through the B port pipe joint 35, passes through the B port first distribution groove 29 and the B port second distribution groove 31 of the B port distribution valve body 21 and enters the first power fluid chamber 28 and the third power fluid chamber 48, and is output to the A port pipe joint 41 through the A port first distribution groove 30 and the A port second distribution groove 32 of the A port distribution valve body 20 to realize the flow of AT;

[0085] The control angle correction process is as follows: If the power stage valve core rotates too much clockwise, the first guide groove 904 of the pilot stage valve core will rotate to connect with the first guide hole 1701 and the first guide hole 4501 of the first floating blade, and the second guide groove 903 of the pilot stage valve core will connect with the fourth guide hole 1704 and the fourth guide hole 4504 of the first floating blade. At this time, the third pilot fluid chamber 43 and the fourth pilot fluid chamber 44 become high-pressure oil chambers, and the first pilot fluid chamber 27 and the second pilot fluid chamber 42 become low-pressure oil chambers. The positions of the high-pressure and low-pressure oil chambers are interchanged. Under the action of the pressure difference, the first floating blade 17 and the second floating blade 45 drive the power stage valve core 14 to rotate counterclockwise through the slot until it is adjusted to the initial position of the first guide groove 904 and the second guide groove 903 of the pilot stage valve core relative to the guide holes of the floating blades. This means that the power stage valve core 14 finally rotates clockwise by α° with the pilot stage valve core 9.

[0086] In summary, the above control method achieves precise mechanical angle feedback in this invention. When an input command is given to rotate ±α°, the power stage valve core 14 can be synchronously rotated with the pilot stage valve core 9, thereby enabling the control of the valve core opening by controlling the rotation signal of the integrated motor, and realizing closed-loop mechanical angle control of the rotary valve.

[0087] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A two-stage rotary servo valve, characterized in that: It includes an integrated motor assembly, a pilot stage valve core assembly, a power stage valve core assembly, and a flow distribution valve body assembly; The integrated motor assembly is used to drive the pilot-stage valve core assembly to rotate, and the pilot-stage valve core assembly is used to drive the power-stage valve core assembly to rotate under the drive of the integrated motor assembly, thereby achieving mechanical angle feedback. The pilot valve core assembly includes a pilot valve core, a floating side plate, a first sealing ring, a second sealing ring, and a third sealing ring. The pilot valve core is connected to the motor rotation shaft of the integrated motor assembly. The first mounting surface of the floating side plate is connected to the second mounting surface of the motor housing of the integrated motor assembly. The first sealing ring, the second sealing ring, and the third sealing ring are respectively placed in three sealing grooves. The power stage valve core assembly includes a power stage valve sleeve, a power stage valve core, rotary valve blades, a rotary valve center spring, a first floating blade, a second floating blade, a first fixed blade, and a second fixed blade. The first mounting surface of the power stage valve sleeve is connected to the second mounting surface of the floating side plate. The inner circumference of the power stage valve sleeve is connected to the power stage valve core. Eight rotary valve blades are evenly distributed on the power stage valve core. The inner circumference of the power stage valve core is connected to the first and second floating blades, which are at 180° intervals, and to the first and second fixed blades, which are also at 180° intervals. The second fixed blade, the first floating blade, the floating side plate, and the... The power stage valve sleeve together constitutes the first pilot fluid cavity; the first fixed vane, the second floating vane, the floating side plate, and the power stage valve sleeve together constitute the second pilot fluid cavity; the first floating vane, the first fixed vane, the floating side plate, and the power stage valve sleeve together constitute the third pilot fluid cavity; the second floating vane, the second fixed vane, the floating side plate, and the power stage valve sleeve together constitute the fourth pilot fluid cavity; the floating side plate, the power stage valve sleeve, the power stage valve core, and eight rotary valve vanes constitute four power fluid cavities, namely the first power fluid cavity, the second power fluid cavity, the third power fluid cavity, and the fourth power fluid cavity; The distribution valve body assembly includes a T-port distribution valve body, an A-port distribution valve body, a B-port distribution valve body, a distribution end cap, an A-port pipe connector, a B-port pipe connector, and a T-port pipe connector; the first mounting surface of the T-port distribution valve body is connected to the second mounting surface of the power stage valve sleeve, the first mounting surface of the A-port distribution valve body is connected to the second mounting surface of the T-port distribution valve body, the first mounting surface of the B-port distribution valve body is connected to the second mounting surface of the A-port distribution valve body, the first mounting surface of the distribution end cap is connected to the second mounting surface of the B-port distribution valve body, and the A-port pipe connector, B-port pipe connector, and T-port pipe connector are all mounted on the second mounting surface of the distribution end cap; When the motor shaft of the integrated motor assembly rotates, it drives the pilot valve core to rotate. The fluid medium enters the first central hole of the pilot valve core through the P-port pipe joint, the P-port distribution groove, the first sinking distribution groove of the pilot valve core, and the first drainage hole of the pilot valve core, and then enters the first drainage groove of the pilot valve core; at the same time, the fluid medium enters the power stage fluid chamber through the P-port pipe joint and the P-port distribution groove. When the pilot valve core rotates, it drives the power valve core to rotate. The first high-pressure fluid medium flowing into the power valve core from the P port connector flows through the A port distribution groove of the A port distribution valve body to the A port connector. The second low-pressure fluid medium flowing into the B port connector enters the power fluid chamber through the B port distribution groove of the B port distribution valve body, and then flows into the T port distribution groove and enters the T port distribution valve body. After that, one low-pressure fluid medium flows out of the T port connector, and the other low-pressure fluid medium sequentially passes through the second sinking distribution groove of the pilot valve core, the second drain hole of the pilot valve core, and enters the second central hole of the pilot valve core, and then enters the second drain groove of the pilot valve core and flows into the pilot valve core. After receiving an electrical signal, the mechanical feedback two-stage rotary servo valve rotates the motor shaft of the integrated motor assembly, which in turn drives the pilot valve core to rotate. The pilot valve core rotates so that the fluid medium flows into the pilot fluid chamber through the drainage holes of the floating blades, driving the power valve core to rotate. If the rotation angle of the power valve core is too large, the high-pressure chamber and the low-pressure chamber are switched. The pressure difference is used to drive the first and second floating blades to rotate the power valve core through the slots until the pilot valve core's first and second drainage slots are adjusted to their initial positions relative to the drainage holes of the floating blades.

2. The two-stage rotary servo valve according to claim 1, characterized in that: The integrated motor assembly includes a motor rotating shaft, a motor rotor, a motor stator, a motor coil, a motor housing, a first valve core retaining ring, a second valve core retaining ring, and a P-port pipe connector; the motor rotor includes a first motor rotor and a second motor rotor, the inner circumference of the motor rotor is fixed to the motor rotating shaft by the first valve core retaining ring and the second valve core retaining ring, the outer circumference of the motor rotor is connected to the motor stator, the motor coil is disposed inside the motor stator, and the P-port pipe connector is disposed inside the motor housing; When the integrated motor assembly is working, it supplies power to the coil through the motor terminal. When there is current between the stator and rotor assemblies of the motor, a magnetic field is generated, which causes the rotor assembly to start moving. The rotor assembly is connected to the motor shaft through a spline, thereby driving the motor shaft to rotate.

3. The two-stage rotary servo valve according to claim 1, characterized in that: The motor terminal is installed on the first mounting surface of the motor end cover. The motor rotating shaft is fixed in the end cover opening of the second mounting surface of the motor end cover through the first rotary valve bearing and the first bearing retaining ring. The first rotary valve bearing, the first bearing retaining ring, the first mounting surface of the motor housing, and the second mounting surface of the motor end cover are connected.

4. The two-stage rotary servo valve according to claim 1, characterized in that: The pilot stage valve core assembly also includes a first plug and a second plug, wherein the first plug is placed in the first threaded hole of the fourth center hole of the pilot stage valve core, and the second plug is placed in the second threaded hole of the fourth center hole of the pilot stage valve core.

5. The two-stage rotary servo valve according to claim 1, characterized in that: The pilot valve core assembly also includes a second rotary valve bearing, a third rotary valve bearing, a second bearing retaining ring, a third valve core retaining ring, and a fourth valve core retaining ring; the second rotary valve bearing is axially positioned on the motor housing by the second bearing retaining ring and fixed on the pilot valve core by the third and fourth valve core retaining rings, and the third rotary valve bearing is axially positioned and fixed between the pilot valve core and the A-port distribution valve body by a sleeve.

6. The two-stage rotary servo valve according to claim 1, characterized in that: Each rotary valve blade is equipped with a rotary valve center spring.

7. The two-stage rotary servo valve according to claim 1, characterized in that: The pilot valve core assembly is also provided with a sleeve.

8. A control method for the two-stage rotary servo valve as described in claim 1, characterized in that: It includes the following steps: S1, Input control commands; S2. The integrated motor assembly drives the pilot stage valve core assembly to rotate ±α according to the control command, and the pilot stage valve core assembly further drives the power stage valve core assembly to rotate. S3. When the rotation angle of the power stage valve core is too large, by switching the high pressure chamber and the low pressure chamber, under the action of the pressure difference, the first floating vane and the second floating vane drive the power stage valve core to rotate in the opposite direction through the slot until they are adjusted to the initial position of the first and second flow channels of the pilot stage valve core relative to the flow holes of the floating vane, so that the power stage valve core rotates ±α° with the pilot stage valve core.

9. The two-stage rotary servo valve control method according to claim 8, characterized in that: When the control command is to distribute current between PA and BT: The input command rotates the motor by -α°. The electrical control signal generates a magnetic field between the motor stator and the motor rotor through the motor coil, and the interaction generates torque to drive the motor rotor to rotate by -α°, which in turn drives the motor shaft to rotate by -α°, which in turn drives the pilot valve core to rotate by -α°. The first pressure oil enters the first sinking distribution groove of the pilot stage valve core through the P-port pipe joint, the P-port distribution groove, and the second P-port distribution groove, and then enters the first central hole of the pilot stage valve core through the first guide hole of the pilot stage valve core, and further enters the first guide groove of the pilot stage valve core. At this time, the pilot stage valve core rotates by -α° to make the first guide groove of the pilot stage valve core connect with the first guide hole of the first floating vane and the first guide hole of the second floating vane. The high-pressure fluid medium in the first guide groove of the pilot stage valve core enters the third pilot fluid through the first guide hole of the first floating vane and the first guide hole of the second floating vane. The second hydraulic oil enters the pilot stage valve core's second central hole through the pilot stage valve core's second sinking distribution groove and the pilot stage valve core's second guide hole via the T-port pipe joint, and then enters the pilot stage valve core's second guide groove. At this time, the pilot stage valve core rotates -α°, and the pilot stage valve core's second guide groove connects with the first floating vane's fourth guide hole and the second floating vane's fourth guide hole. The low-pressure fluid medium in the pilot stage valve core's second guide groove enters the first pilot fluid cavity and the second pilot fluid cavity through the first floating vane's fourth guide hole and the second floating vane's fourth guide hole. When the third and fourth pilot fluid chambers are high-pressure oil chambers, and the first and second pilot fluid chambers are low-pressure oil chambers, the first and second floating vanes drive the power stage valve core to rotate through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chambers. Driven by the pilot valve core, the first hydraulic oil enters the first power fluid chamber and the third power fluid chamber through the P-port pipe connector, the P-port distribution groove and the second P-port distribution groove, and then is output to the A-port pipe connector through the A-port first distribution groove and the A-port second distribution groove of the A-port distribution valve body, realizing the flow of PA; at the same time, the second hydraulic oil flows in through the B-port pipe connector, flows through the B-port first distribution groove and the B-port second distribution groove of the B-port distribution valve body, enters the second power fluid chamber and the fourth power fluid chamber, then flows into the T-port first distribution groove, enters the T-port distribution valve body, and then flows out to the T-port pipe connector, realizing the flow of BT; If the power stage valve core rotates too much, the first guide groove of the pilot stage valve core will rotate to connect with the second guide hole of the first floating vane and the second guide hole of the second floating vane, and the second guide groove of the pilot stage valve core will connect with the third guide hole of the first floating vane and the third guide hole of the second floating vane. At this time, the third pilot fluid chamber and the fourth pilot fluid chamber become low-pressure oil chambers, and the first pilot fluid chamber and the second pilot fluid chamber become high-pressure oil chambers. Under the action of pressure difference, the first floating vane and the second floating vane drive the power stage valve core to rotate in the opposite direction through the slot until they are adjusted to the initial position of the first guide groove and the second guide groove of the pilot stage valve core relative to the guide holes of the floating vane, so that the power stage valve core rotates -α° with the pilot stage valve core.

10. The two-stage rotary servo valve control method according to claim 8, characterized in that: When the control command is to allocate current between PB connection and AT connection: The input command rotates by +α°. The electrical control signal generates a magnetic field between the motor stator and the motor rotor through the motor coil, and the interaction produces a torque that drives the motor rotor to rotate by +α°, drives the motor shaft to rotate by +α, and then drives the pilot valve core to rotate by +α°. The first pressure oil enters the first sinking distribution groove of the pilot valve core through the P-port pipe joint, the P-port distribution groove and the second P-port distribution groove, and enters the first central hole of the pilot valve core through the first guide hole of the pilot valve core, and then enters the first guide groove of the pilot valve core. At this time, the pilot valve core rotates by +α° to make the first guide groove of the pilot valve core rotate to connect with the second guide hole of the first floating blade and the second guide hole of the second floating blade. The high pressure fluid medium in the first guide groove of the pilot valve core enters the first pilot fluid cavity and the second pilot fluid cavity through the second guide hole of the first floating blade and the second guide hole of the second floating blade. The second hydraulic oil enters the second central hole of the pilot valve core through the second sinking distribution groove and the second guide hole of the pilot valve core via the T-port pipe joint, and then enters the second guide groove of the pilot valve core. At this time, the pilot valve core rotates +α°, and the second guide groove of the pilot valve core connects with the third guide hole of the first floating vane and the third guide hole of the second floating vane. The low-pressure fluid medium in the second guide groove of the pilot valve core enters the third pilot fluid chamber and the fourth pilot fluid chamber through the third guide hole of the first floating vane and the third guide hole of the second floating vane. When the third and fourth pilot fluid chambers are low-pressure oil chambers, and the first and second pilot fluid chambers are high-pressure oil chambers, the first and second floating vanes drive the power stage valve core to rotate through the slot under the pressure difference between the high-pressure fluid medium and the low-pressure fluid medium in the pilot fluid chambers. Driven by the pilot valve core, the first hydraulic oil enters the second power fluid chamber and the fourth power fluid chamber through the P-port pipe connector, the P-port distribution groove and the second P-port distribution groove, flows into the T-port first distribution groove and the T-port first distribution groove into the T-port distribution valve body, and then flows out to the T-port pipe connector, realizing the flow of PB; at the same time, the second hydraulic oil flows in through the B-port pipe connector, flows through the B-port first distribution groove and the B-port second distribution groove of the B-port distribution valve body, enters the first power fluid chamber and the third power fluid chamber, and is output to the A-port pipe connector through the A-port first distribution groove and the A-port second distribution groove of the A-port distribution valve body, realizing the flow of AT; If the power stage valve core rotates too much, causing the first guide groove of the pilot stage valve core to rotate to connect with the first guide hole of the first floating vane and the first guide hole of the second floating vane, and the second guide groove of the pilot stage valve core to connect with the fourth guide hole of the first floating vane and the fourth guide hole of the second floating vane, then the third and fourth pilot fluid chambers become high-pressure oil chambers, and the first and second pilot fluid chambers become low-pressure oil chambers. Under the action of the pressure difference, the first and second floating vanes drive the power stage valve core to rotate in the opposite direction through the slots until they are adjusted to the initial positions of the first and second guide grooves of the pilot stage valve core relative to the guide holes of the floating vanes, thus achieving a final rotation of +α° with the pilot stage valve core.

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