Variable-damping actively controlled squeeze film damper and variable-damping adjustment method thereof

Abstract

This invention relates to a variable-damping, actively controlled extrusion film damper and its variable-damping adjustment method, belonging to the technical field of extrusion film damper structural design for aero-engines. The invention addresses the problem that traditional extrusion film dampers only exhibit optimal damping characteristics at specific excitation frequencies, failing to cover all rotor operating frequencies. This results in poor stability and weak dynamic performance of the rotor system in modern aero-engines operating across multiple critical speeds. The invention comprises a damper outer ring, a cone sleeve, a squirrel cage inner ring, two servo valves, two oil film pressure sensors, and two eddy current displacement sensors. Lubricating oil enters the oil film between the cone sleeve and the squirrel cage inner ring through the two servo valves. The eddy current displacement sensors measure the change in the eddy current position of the squirrel cage inner ring, and the oil film pressure sensors measure the change in oil film pressure. The measurements from the eddy current displacement sensors and the oil film pressure sensors are used as the basis for adjusting the oil supply to the servo valves. This invention is primarily used as a structure for extrusion film dampers in aero-engines.

Description

Technical Field

[0001] This invention belongs to the technical field of aero-engine extrusion film damper structure design, specifically relating to a variable damping active control extrusion film damper and its variable damping adjustment method. Background Technology

[0002] An extrusion film damper is a passive vibration reduction device that utilizes the dissipation effect generated by viscous fluid in extrusion flow to increase system damping. Due to its simple structure and high reliability, extrusion film dampers are widely used in modern aero-engines. A scientifically designed extrusion film damper can effectively isolate structural vibrations and reduce external excitation of the rotor, thereby reducing the impact of rotating components on the supporting structure.

[0003] Traditional extrusion film dampers exhibit optimal damping characteristics only at specific excitation frequencies, failing to cover all rotor operating frequencies. Therefore, research into the structural design of actively controlled extrusion film dampers with variable damping is essential to enabling modern aero-engines to achieve excellent vibration reduction capabilities across the entire power and speed range during operation across multiple critical speeds. This, in turn, improves rotor system stability, extends engine lifespan, and enhances its dynamic performance, aligning with practical needs. Summary of the Invention

[0004] In order to solve the problem that traditional extrusion film dampers only have optimal damping characteristics at specific excitation frequencies and cannot cover all rotor operating frequencies, resulting in poor stability and weak dynamic performance of the rotor system in modern aero engines during operation across multiple critical speeds, this invention provides a variable damping active control extrusion film damper and its variable damping adjustment method.

[0005] A variable-damping, actively controlled extrusion film damper includes an outer ring, a cone sleeve, an inner ring of a squirrel cage, two servo valves, two oil film pressure sensors, and two eddy current displacement sensors. The cone sleeve is fitted onto the inner ring of the squirrel cage, and the outer ring of the damper is fitted onto the cone sleeve. The two servo valves are circumferentially and equidistantly mounted on the outer surface of the outer ring of the damper. The two oil film pressure sensors are symmetrically arranged on both sides of one of the servo valves. Each oil film pressure sensor is mounted on the outer ring of the damper, and the sensing end of each oil film pressure sensor extends to the cone sleeve and the inner ring of the squirrel cage. Within the oil film zone between the rings, two eddy current displacement sensors are installed at the front end of the outer ring of the damper, and each eddy current displacement sensor is correspondingly set with an oil film pressure sensor. The detection end of each eddy current displacement sensor is set with the outer circular wall of the inner ring of the squirrel cage. The lubricating oil enters the oil film between the cone sleeve and the inner ring of the squirrel cage through two servo valves. The change of the eddy current displacement sensor measures the change of the eddy current position of the inner ring of the squirrel cage, and the change of the oil film pressure sensor measures the change of the oil film pressure. The measured values ​​of the eddy current displacement sensor and the oil film pressure sensor are used as the basis for adjusting the oil supply of the servo valve.

[0006] Furthermore, two servo valve mounting blocks are equidistantly arranged circumferentially on the outer ring surface of the damper outer ring. Each servo valve mounting block is integrally formed with the damper outer ring, and each servo valve is installed on one servo valve mounting block. Two No. 1 oil film pressure sensor mounting holes are also machined on the outer ring surface of the damper outer ring, and the two No. 1 oil film pressure sensor mounting holes are symmetrically arranged on both sides of one servo valve mounting block. Two oil return grooves are sequentially machined on the inner ring surface of the damper outer ring along the axial extension direction of the damper outer ring, and each oil return groove is connected to one servo valve mounting block.

[0007] Furthermore, two No. 1 oil passage holes are machined inside the outer ring of the damper, each No. 1 oil passage hole is connected to a servo valve mounting block, and a No. 1 oil return hole is machined on the bottom of each oil return groove, and each oil return groove is connected to the servo valve mounting block through the No. 1 oil return hole.

[0008] Furthermore, four servo valve connection holes are machined at the top edge of the servo valve mounting block. The servo valve is detached and connected to the servo valve mounting block through the four servo valve connection holes and locking bolts. At the center of the top of the servo valve mounting block, there are external oil inlet holes, servo valve outlet holes, servo valve return holes, and external oil return holes respectively. One end of the external oil inlet hole is connected to the outlet end of the external oil supply equipment through an oil pipe, and the other end of the external oil inlet hole is connected to the inlet hole in the servo valve through an oil pipe. One end of the servo valve outlet hole is connected to the outlet hole of the servo valve through an oil pipe, and the other end of the servo valve outlet hole is connected to the inlet end of the first oil outlet hole. One end of the servo valve return hole is connected to the return hole of the servo valve through an oil pipe, and the other end of the servo valve return hole is connected to the outlet end of the first return hole through an oil pipe. One end of the external oil return hole is connected to the drain hole of the servo valve through an oil pipe, and the other end of the external oil return hole is connected to the inlet end of the external oil supply equipment through an oil pipe.

[0009] Furthermore, the No. 1 oil passage is an L-shaped oil passage. One end of the No. 1 oil passage is connected to the side wall of the corresponding servo valve mounting block, and the other end of the No. 1 oil passage is connected to the inner ring surface of the outer ring of the damper. A sealing plug is provided on the end of the No. 1 oil passage that connects to the side wall of the servo valve mounting block.

[0010] Furthermore, two No. 2 oil passage holes are machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve. Each No. 2 oil passage hole is connected to a No. 1 oil passage hole. Two No. 2 oil return hole groups are machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve. Each No. 2 oil return hole group includes two No. 2 oil return holes, and one No. 2 oil return hole in each No. 2 oil return hole group is connected to a return oil groove. Two No. 2 oil film pressure sensor mounting holes are also machined on the outer ring surface of the tapered sleeve. Each No. 2 oil film pressure sensor mounting hole is coaxially connected to a No. 1 oil film pressure sensor mounting hole.

[0011] Furthermore, two sealing ring mounting grooves are machined on the outer ring surface of the cone sleeve along the axial extension direction of the cone sleeve, and the two piston ring mounting grooves are symmetrically arranged on both sides of the mounting holes of the two No. 2 oil film pressure sensors. Each sealing ring mounting groove has a sealing ring, and the cone sleeve is sealed with the outer ring of the damper through the two sealing rings.

[0012] Furthermore, the outer circumference of the inner ring of the squirrel cage is machined with an oil inlet ring groove and two piston ring mounting grooves. The two piston ring mounting grooves are symmetrically arranged on both sides of the oil inlet ring groove. The oil inlet ring groove is connected to two No. 2 oil passage holes. Each piston ring mounting groove contains a piston ring. The inner ring of the squirrel cage is sealed with the cone sleeve through two piston rings.

[0013] Furthermore, the eddy current displacement sensor is mounted on the front end of the damper outer ring via an L-shaped mounting bracket. Two sets of eddy current displacement sensor mounting holes are machined on the front end face of the damper outer ring. Each set of eddy current displacement sensor mounting holes corresponds to a No. 1 oil film pressure sensor mounting hole. The vertical part of the L-shaped mounting bracket is mounted on the front end of the damper outer ring by bolts and mating with a set of eddy current displacement sensor mounting holes. The eddy current displacement sensor is embedded in the horizontal part of the L-shaped mounting bracket.

[0014] A variable damping active control squeeze film damper variable damping adjustment method is specifically implemented through the following steps:

[0015] Step 1: Complete the installation of the specific rotor and the controllable extrusion oil film damper;

[0016] Step 2: The rotor begins to rotate, driving the squirrel cage inner ring in the controllable extrusion oil film damper to vortex;

[0017] Step 3: As the inner ring of the squirrel cage vortexes, the oil film pressure sensor begins to monitor the oil film pressure changes between the inner ring of the squirrel cage and the cone sleeve in real time, and the eddy current displacement sensor monitors the position changes of the inner ring of the squirrel cage in real time. The data acquisition system records the oil film pressure data and the eddy current displacement sensor data as feedback parameters.

[0018] Step 4: When the eddy current displacement sensor detects a change in the eddy current position of the inner ring of the squirrel cage, the PLC control board controls the servo valve that is close to the eddy current position of the inner ring of the squirrel cage to increase the oil supply pressure, while the servo valve that is far from the eddy current position of the inner ring of the squirrel cage supplies oil with a smaller oil supply pressure. This allows for real-time adjustment of the real-time damping performance of the variable damping extrusion oil film damper. For the inner ring of the squirrel cage, which is commonly used in engineering, to perform synchronous circular trajectory motion, the oil supply pressure controlled by the servo valve changes according to a sine law.

[0019] Step 5: Verify the variable damping characteristics of the adjusted controllable extrusion oil film damper to determine whether the above adjustment steps have achieved the expected effect of variable damping.

[0020] The beneficial effects of this application compared to the prior art are:

[0021] This application proposes a variable-damping, actively controlled extrusion film damper. An eddy current displacement sensor monitors the position change of the inner ring in the extrusion film damper in real time and feeds this change back to the control system. Simultaneously, an oil film pressure sensor monitors the oil film pressure signal of the extrusion film damper. The control system then controls two servo valves evenly distributed circumferentially within the controllable extrusion film damper to supply oil at a controlled pressure. Lubricating oil, at a certain pressure, exits the servo valves and enters the oil film through the outer ring and oil holes in the cone sleeve. Within the oil film, it is evenly distributed to the circumferential surface of the squirrel cage extension via an annular oil groove. It then returns to the space between the cone sleeve and the outer ring through the return oil hole in the cone sleeve, subsequently entering the annular oil passage in the outer ring, and finally entering the return oil hole of the servo valve through the return oil hole of the outer ring, ultimately exiting the damper structure. Through this process, the oil supply pressure of the damper can be controlled, thereby controlling the damping characteristics of the damper. Attached Figure Description

[0022] Figure 1 This is a general structural diagram of the variable damping active control squeeze film damper described in this application;

[0023] Figure 2 This is a schematic diagram of the structure of the outer ring of the damper in the variable damping active control squeeze oil film damper described in this application;

[0024] Figure 3 This is a schematic diagram of the cone sleeve in the variable damping active control extrusion oil film damper described in this application;

[0025] Figure 4 This is a schematic diagram of the inner ring of the squirrel cage in the variable damping active control extrusion oil film damper described in this application;

[0026] Figure 5 This is a schematic diagram of the oil film pressure sensor in the variable damping active control extrusion oil film damper described in this application;

[0027] Figure 6 This is a schematic diagram of the servo valve in the variable damping active control extrusion film damper described in this application;

[0028] Figure 7 This is a block diagram of the servo valve transfer function in the variable damping active control extrusion film damper described in this application;

[0029] Figure 8 This is a diagram of the piston ring structure in the variable damping active control extrusion film damper described in this application;

[0030] Figure 9 This is a cross-sectional view of the variable damping active control extrusion film damper described in this application from the oil inlet perspective.

[0031] Figure 10This is a cross-sectional view of the variable damping active control extrusion film damper described in this application from the perspective of oil return:

[0032] Figure 11 This is a cross-sectional view of the variable damping active control extrusion oil film damper described in this application from the perspective of the oil film pressure sensor.

[0033] Figure 12 This is the damping test bench for the variable damping extrusion oil film damper used in this application to verify the oil film damping effect;

[0034] Figure 13 This is the damping test bench for the variable damping extrusion oil film damper used in this application to verify the oil film damping effect;

[0035] The diagram shows: 1. Damper outer ring; 11. Servo valve mounting block; 12. No. 1 oil film pressure sensor mounting hole; 13. Return oil groove; 14. Servo valve connection hole; 15. External oil inlet hole; 16. Servo valve outlet hole; 17. Servo valve return oil hole; 18. External oil return oil hole; 19. No. 1 oil flow hole; 110. No. 1 return oil hole; 2. Cone sleeve; 21. Piston ring mounting groove; 22. No. 2 oil flow hole; 23. No. 2 return oil hole; 24. No. 2 oil film pressure sensor mounting hole; 3. Squirrel cage inner ring; 31. Oil inlet ring groove; 32. Piston ring mounting groove; 4. Servo valve; 5. Oil film pressure sensor; 6. Eddy current displacement sensor; and 7. Piston ring. Detailed Implementation

[0036] Specific implementation method one: Combining Figures 1 to 11 This embodiment describes a variable-damping actively controlled extrusion film damper. The actively controlled extrusion film damper includes an outer ring 1, a cone sleeve 2, a squirrel cage inner ring 3, two servo valves 4, two oil film pressure sensors 5, and two eddy current displacement sensors 6. The cone sleeve 2 is fitted onto the squirrel cage inner ring 3, and the outer ring 1 is fitted onto the cone sleeve 2. The two servo valves 4 are equidistantly mounted circumferentially on the outer surface of the outer ring 1. The two oil film pressure sensors 5 are symmetrically arranged on both sides of one servo valve 4, and are offset at 90°. Each oil film pressure sensor 5 is mounted on the outer ring 1 of the damper. The detection end of the pressure sensor 5 extends into the oil film area between the cone sleeve 2 and the inner ring 3 of the squirrel cage. Two eddy current displacement sensors 6 are installed at the front end of the outer ring 1 of the damper, and each eddy current displacement sensor 6 is correspondingly set with an oil film pressure sensor 5. The detection end of each eddy current displacement sensor 6 is set with the outer circular wall of the inner ring 3 of the squirrel cage. The lubricating oil enters the oil film between the cone sleeve 2 and the inner ring 3 of the squirrel cage through two servo valves 4. The eddy current displacement sensor 6 measures the change in the eddy current position of the inner ring 3 of the squirrel cage, and the oil film pressure sensor 5 measures the change in the oil film pressure. The measured values ​​of the eddy current displacement sensor 6 and the oil film pressure sensor 5 are used as the basis for adjusting the oil supply of the servo valve 4.

[0037] The active control extrusion oil film damper provided in this application can adjust the oil supply pressure through a servo valve based on the oil film pressure change detected by the oil film pressure sensor, thereby actively controlling the damping of the extrusion oil film damper structure to achieve the effect of reducing the vibration amplitude of the aero-engine and optimizing the dynamic performance under multiple operating conditions. Flanges for machining are respectively provided on the squirrel cage inner ring 3 and the cone sleeve 2. The bolt hole positions at the flanges of the squirrel cage inner ring 3 and the cone sleeve 2 are matched to facilitate fixing in the aero-engine rotor structure. An oil film gap with a thickness of 0.2mm is provided between the extension of the squirrel cage inner ring 3 and the cone sleeve 2.

[0038] Specific Implementation Method Two: Combining Figures 1 to 11 This embodiment differs from specific embodiment one in that two servo valve mounting blocks 11 are equidistantly spaced along the circumferential direction on the outer ring surface of the damper outer ring 1. Each servo valve mounting block 11 is integrally formed with the damper outer ring 1, and each servo valve 4 is mounted on one servo valve mounting block 11. Two No. 1 oil film pressure sensor mounting holes 12 are also machined on the outer ring surface of the damper outer ring 1, and the two No. 1 oil film pressure sensor mounting holes 12 are symmetrically arranged on both sides of one servo valve mounting block 11. Two oil return grooves 13 are sequentially machined along the axial direction of the damper outer ring 1 on the inner ring surface of the damper outer ring 1, and each oil return groove 13 is connected to one servo valve mounting block 11. Other components and connections are the same as in specific embodiment one.

[0039] Specific implementation method three: Combining Figures 1 to 11 This embodiment differs from Specific Embodiment Two in that two No. 1 oil passage holes 19 are machined inside the outer ring 1 of the damper. Each No. 1 oil passage hole 19 is connected to a servo valve mounting block 11. A No. 1 oil return hole 110 is machined on the bottom of each oil return groove 13, and each oil return groove 13 is connected to the servo valve mounting block 11 through the No. 1 oil return hole 110. Other components and connection methods are the same as in Specific Embodiment Two.

[0040] Specific implementation method four: Combination Figures 1 to 11This embodiment differs from Specific Embodiment Three in that four servo valve connection holes 14 are machined at the top edge of the servo valve mounting block 11. The servo valve 4 is detachably connected to the servo valve mounting block 11 through the four servo valve connection holes 14 and locking bolts. An external oil inlet hole 15, a servo valve outlet hole 16, a servo valve return hole 17, and an external oil return hole 18 are machined at the center of the top of the servo valve mounting block 11. One end of the external oil inlet hole 15 is connected to the outlet end of an external oil supply device via an oil pipe. The other end of the external oil inlet hole 15... One end of the servo valve is connected to the oil inlet of the servo valve 4 via an oil pipe. One end of the servo valve outlet 16 is connected to the oil outlet of the servo valve 4 via an oil pipe. The other end of the servo valve outlet 16 is connected to the oil inlet of the first oil outlet 19. One end of the servo valve return 17 is connected to the return port of the servo valve 4 via an oil pipe. The other end of the servo valve return 17 is connected to the oil outlet of the first return 110 via an oil pipe. One end of the external oil return 18 is connected to the drain port of the servo valve 4 via an oil pipe. The other end of the external oil return 18 is connected to the oil inlet of the external oil supply equipment via an oil pipe. Other components and connections are the same as in specific embodiment three.

[0041] As described in conjunction with specific embodiments two to four, the outer ring 1 of the damper has a servo valve mounting block 11 designed for installing the servo valve 4. The servo valve mounting block 11 is machined with holes corresponding to the positions of the servo valve oil holes, as well as oil grooves and oil holes for lubricating oil flow. Through the oil circuit formed by the external oil inlet hole 15, the servo valve outlet hole 16, the servo valve return hole 17, and the external oil return hole 18, the oil can enter the servo valve 4 from the external oil supply device, then enter the oil circuit in the damper through the servo valve 4, and finally return to the external oil supply device through the servo valve 4, thus realizing the circulation of the oil.

[0042] Specific Implementation Method Five: Combining Figures 1 to 11 This embodiment differs from Specific Embodiment Four in that the first oil passage 19 is an L-shaped oil passage. One end of the first oil passage 19 is connected to the side wall of the corresponding servo valve mounting block 11, and the other end of the first oil passage 19 is connected to the inner ring surface of the damper outer ring 1. A sealing plug is provided on the end of the first oil passage 19 that connects to the side wall of the servo valve mounting block 11. Other components and connection methods are the same as in Specific Embodiment Four.

[0043] In this embodiment, the first oil passage 19 is an L-shaped oil passage to facilitate the processing of the oil passage. Due to the arrangement of the hole system, the first oil passage 19 and the second oil passage 22 are not coaxially arranged. In order to ensure that the oil can diffuse from the middle to both sides to form the final oil film, the servo valve outlet 16 is connected to the horizontal part of the first oil passage 19 and flows through the vertical part of the first oil passage 19 to the second oil passage 22, and finally enters the oil inlet ring groove 31 along the second oil passage 22. As the oil diffuses in the oil inlet ring groove 31 into the oil film gap, it finally forms an oil film.

[0044] Specific Implementation Method Six: Combination Figures 1 to 11 This embodiment differs from specific embodiment five in that two second-order oil passage holes 22 are machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve 2. Each second-order oil passage hole 22 is correspondingly connected to a first-order oil passage hole 19. Two sets of second-order oil return holes are also machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve 2. Each set of second-order oil return holes includes two second-order oil return holes 23, and one second-order oil return hole 23 in each set is correspondingly connected to a return groove 13. Two second-order oil film pressure sensor mounting holes 24 are also machined on the outer ring surface of the tapered sleeve 2, and each second-order oil film pressure sensor mounting hole 24 is coaxially corresponding to a first-order oil film pressure sensor mounting hole 12. Other components and connection methods are the same as in specific embodiment five.

[0045] Specific implementation method seven: Combining Figures 1 to 11 This embodiment differs from specific embodiment six in that two sealing ring mounting grooves 21 are machined on the outer ring surface of the cone sleeve 2 along the axial direction of the cone sleeve 2. The two piston ring mounting grooves 21 are symmetrically arranged on both sides of the two second oil film pressure sensor mounting holes 24. Each sealing ring mounting groove 21 contains a sealing ring, and the cone sleeve 2 is sealed to the damper outer ring 1 through the two sealing rings. Other components and connection methods are the same as in specific embodiment six.

[0046] As described in Specific Embodiments Six and Seven, the cone sleeve 2 has two holes machined on its outer ring surface for installing oil film pressure sensors and related inlet and outlet oil holes, which are used for the flow of lubricating oil between the outer ring of the servo valve and damper and the inner ring of the squirrel cage. At the same time, the cone sleeve structure has a flange structure that matches the inner ring of the squirrel cage, which facilitates the installation and fixation of the variable damping controllable extrusion oil film damper structure in the aero-engine rotor system. The sealing ring is used to increase the sealing performance of the damper and prevent oil leakage.

[0047] Specific implementation method eight: Combination Figures 1 to 11This embodiment differs from specific embodiment seven in that the outer circumference of the inner ring 3 of the squirrel cage is machined with an oil inlet ring groove 31 and two piston ring mounting grooves 32. The two piston ring mounting grooves 32 are symmetrically arranged on both sides of the oil inlet ring groove 31. The oil inlet ring groove 31 is connected to two second oil passage holes 22. Each piston ring mounting groove 32 contains a piston ring 7. The inner ring 3 of the squirrel cage is sealed to the cone sleeve 2 through the two piston rings 7. Other components and connection methods are the same as in specific embodiment seven.

[0048] In this embodiment, the squirrel cage inner ring 3 is divided into a flange part, a squirrel cage bar part, and a damper inner ring part. The flange part is used to fix the squirrel cage and the entire variable damping active control variable damping extrusion oil film damper. The squirrel cage bar part is used to provide flexible support stiffness in the rotor support structure. The damper inner ring part is used for the inner wall of the oil film of the variable damping extrusion oil film damper. The damper inner ring part has an circumferential oil supply groove for evenly distributing lubricating oil and a circumferential annular groove for installing piston rings, and the piston ring 7 achieves a seal with the cone sleeve 2.

[0049] Specific Implementation Method Nine: Combining Figures 1 to 11 This embodiment differs from specific embodiment eight in that the eddy current displacement sensor 6 is mounted on the front end of the damper outer ring 1 via an L-shaped mounting bracket. Two sets of eddy current displacement sensor mounting holes are machined on the front end face of the damper outer ring 1, with each set corresponding to a No. 1 oil film pressure sensor mounting hole 12. The vertical part of the L-shaped mounting bracket is mounted on the front end of the damper outer ring 1 via bolts that engage with one set of eddy current displacement sensor mounting holes. The eddy current displacement sensor 6 is embedded in the horizontal part of the L-shaped mounting bracket. Other components and connection methods are the same as in specific embodiment eight.

[0050] Specific Implementation Method Ten: Combining Figures 1 to 13 This embodiment describes a variable damping adjustment method for an actively controlled, variable-damping squeeze film damper. The adjustment method is implemented through the following steps:

[0051] Step 1: Complete the installation of the specific rotor and the controllable extrusion oil film damper;

[0052] Step 2: The rotor starts to rotate, driving the squirrel cage inner ring 3 in the controllable extrusion oil film damper to vortex;

[0053] Step 3: As the inner ring 3 of the squirrel cage oscillates, the oil film pressure sensor 5 begins to monitor the oil film pressure change between the inner ring 3 of the squirrel cage and the cone sleeve 2 in real time, and the eddy current displacement sensor 6 monitors the position change of the inner ring 3 of the squirrel cage in real time. The data acquisition system records the oil film pressure data and the eddy current displacement sensor data as feedback parameters.

[0054] Step 4: When the eddy current displacement sensor 6 detects a change in the eddy position of the inner ring 3 of the squirrel cage, the PLC control board controls the servo valve 4, which is close to the eddy position of the inner ring 3 of the squirrel cage, to increase the oil supply pressure, while the servo valve 4, which is far from the eddy position of the inner ring 3 of the squirrel cage, supplies oil with a smaller oil supply pressure. This allows for real-time adjustment of the real-time damping performance of the variable damping extrusion oil film damper. For the inner ring 3 of the squirrel cage, which is commonly used in engineering, to perform synchronous circular trajectory motion, the oil supply pressure controlled by the servo valve 4 changes according to a sine law.

[0055] Step 5: Verify the variable damping characteristics of the adjusted controllable extrusion oil film damper to determine whether the above adjustment steps have achieved the expected effect of variable damping.

[0056] In this embodiment, the servo valve type used is a nozzle-baffle electro-hydraulic flow servo valve. The working principle of the servo valve is to control the valve opening by input current, thereby controlling the input flow rate and pressure. The servo valve transfer function block diagram is shown below. Figure 7 As shown, in Figure 7 In this context, i represents the input current, and K... t K represents the electromagnetic torque coefficient of the torque motor in the servo valve. an ω represents the overall stiffness of the torque motor. mf J represents the natural frequency of the torque motor. an This represents the moment of inertia of the armature assembly. B represents the relative damping coefficient of a torque motor. a The torque motor's viscous damping coefficient is represented by s; the Laplace operator is represented by θ; the baffle deflection angle is represented by r; and the distance from the center of rotation to the center of the nozzle is represented by x. f Indicates the baffle displacement; K q Indicates the pre-stage flow gain; A v Indicates the valve core end area; x v Indicates valve core displacement; K f Let be the feedback rod stiffness; b is the distance from the center of the ball to the center of the nozzle. Therefore, the closed-loop transfer function of the servo valve can be obtained as:

[0057]

[0058] Equation (1) shows the transfer function representing the relationship between the input current and the valve opening. The valve opening and the output flow rate have a linear relationship, while the relationship between the output flow rate and the output pressure is as follows:

[0059]

[0060] In equation (2), Q represents the actual flow rate of the servo valve. N ΔP represents the rated flow rate of the servo valve, and ΔP represents the actual pressure drop at each throttling edge of the servo valve. NThis indicates the rated pressure drop of the servo valve. By combining equations (1) and (2), the relationship between the input current and output pressure of the servo valve can be established. Based on this relationship, the output pressure of the servo valve can be controlled by the controller through the input current, thereby controlling the damping characteristics of the damper.

[0061] During the operation of the variable damping extrusion film damper, the rotor's whirl motion causes periodic changes in the flow between the oil film gaps. Backflow in the high-pressure region and cavitation in the low-pressure region alternate, and the flow state is significantly affected by the oil supply and end-seal leakage, thus directly determining the damping and vibration reduction characteristics of the extrusion film damper. Therefore, this invention integrates the oil supply and return of the servo valve with the main structure of the extrusion film damper through a squirrel cage, outer ring, and cone sleeve structure to achieve better active control dynamic response characteristics. The displacement signal of the inner ring of the damper and the pressure signal of the damper's oil film are used as feedback parameters for the controller. By adjusting the servo valve's oil supply pressure at different positions and times, the dynamic performance of the damper can be adjusted, effectively reducing the cavitation area, optimizing the damper's damping performance, achieving real-time control of the damper's damping characteristics, and reducing the rotor vibration amplitude.

[0062] Step 5 in this embodiment is to test the variable damping characteristics of the active control extrusion oil film damper provided in this application. The test requires the use of a variable damping extrusion oil film damper damping test bench, such as... Figure 12 and Figure 13 As shown, the variable damping extrusion film damper damping test bench uses orthogonal excitation rods to orthogonally excite the variable damping extrusion film damper. Force and load sensors at corresponding positions measure the force and load at the orthogonal positions, and the corresponding damping is calculated to verify and adjust the variable damping adjustment effect of the variable damping extrusion film damper. The specific verification principle involves placing the controllable extrusion film damper to be verified on the prepared test bench and orthogonally arranging the excitation rods. The combination of the excitation amplitude and phase of the orthogonal excitation rods can simulate different squirrel cage vortex patterns in actual use. Force and displacement sensors relative to the excitation rod positions measure the force and displacement data during excitation. Based on the vortex pattern and the corresponding force and displacement data, and according to c = F / v (where c represents damping, F represents excitation force, and v represents excitation velocity), the corresponding damping characteristics can be calculated, thus verifying the variable damping performance of the controllable extrusion film damper.

[0063] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A variable-damping actively controlled extrusion film damper, characterized in that: The active control squeezing oil film damper includes a damper outer ring (1), a cone sleeve (2), a squirrel cage inner ring (3), two servo valves (4), two oil film pressure sensors (5), and two eddy current displacement sensors (6). The cone sleeve (2) is fitted onto the squirrel cage inner ring (3), and the damper outer ring (1) is fitted onto the cone sleeve (2). The two servo valves (4) are equidistantly mounted on the outer circumferential surface of the damper outer ring (1). The two oil film pressure sensors (5) are symmetrically arranged on both sides of one servo valve (4), and the two oil film pressure sensors (5) are offset at 90°. Each oil film pressure sensor (5) is mounted on the damper outer ring (1), and the detection end of each oil film pressure sensor (5) extends to the cone sleeve (2). In the oil film area between the cone sleeve (2) and the inner ring (3) of the squirrel cage, two eddy current displacement sensors (6) are installed at the front end of the outer ring (1) of the damper, and each eddy current displacement sensor (6) is set with an oil film pressure sensor (5). The detection end of each eddy current displacement sensor (6) is set with the outer circular wall of the inner ring (3) of the squirrel cage. The lubricating oil enters the oil film between the cone sleeve (2) and the inner ring (3) of the squirrel cage through two servo valves (4). The eddy current displacement sensor (6) measures the change of the eddy current position of the inner ring (3) of the squirrel cage, and the oil film pressure sensor (5) measures the change of the oil film pressure. The measured values ​​of the eddy current displacement sensor (6) and the oil film pressure sensor (5) are used as the basis for adjusting the oil supply of the servo valve (4). When the eddy current displacement sensor (6) detects a change in the eddy position of the inner ring (3) of the squirrel cage, the PLC control board controls the servo valve (4) that is close to the eddy position of the inner ring (3) of the squirrel cage to increase the oil supply pressure, while the servo valve (4) that is far from the eddy position of the inner ring (3) of the squirrel cage supplies oil with a smaller oil supply pressure, thereby adjusting the real-time damping performance of the active control extrusion oil film damper in real time.

2. The variable damping actively controlled extrusion film damper according to claim 1, characterized in that: Two servo valve mounting blocks (11) are equidistantly arranged on the outer ring surface of the damper outer ring (1) along the circumferential direction. Each servo valve mounting block (11) is integrally formed with the damper outer ring (1). Each servo valve (4) is installed on a corresponding servo valve mounting block (11). Two No. 1 oil film pressure sensor mounting holes (12) are also machined on the outer ring surface of the damper outer ring (1). The two No. 1 oil film pressure sensor mounting holes (12) are symmetrically arranged on both sides of a servo valve mounting block (11). Two oil return grooves (13) are sequentially machined on the inner ring surface of the damper outer ring (1) along the axial extension direction of the damper outer ring (1). Each oil return groove (13) is connected to a servo valve mounting block (11).

3. The variable damping actively controlled extrusion film damper according to claim 2, characterized in that: Two No. 1 oil passage holes (19) are machined inside the outer ring (1) of the damper. Each No. 1 oil passage hole (19) is connected to a servo valve mounting block (11). A No. 1 oil return hole (110) is machined on the bottom of each oil return groove (13), and each oil return groove (13) is connected to the servo valve mounting block (11) through the No. 1 oil return hole (110).

4. The variable damping actively controlled extrusion film damper according to claim 3, characterized in that: Four servo valve connection holes (14) are machined at the top edge of the servo valve mounting block (11). The servo valve (4) is detached and connected to the servo valve mounting block (11) through the four servo valve connection holes (14) and locking bolts. At the center of the top of the servo valve mounting block (11), an external oil inlet hole (15), a servo valve outlet hole (16), a servo valve return hole (17), and an external oil return hole (18) are machined respectively. One end of the external oil inlet hole (15) is connected to the oil outlet of an external oil supply device through an oil pipe, and the other end of the external oil inlet hole (15) is connected to the servo valve (4) through an oil pipe. The oil inlet of the servo valve is connected to the oil outlet of the servo valve (4) through an oil pipe. The other end of the oil outlet of the servo valve (16) is connected to the oil inlet of the first oil outlet (19). One end of the oil return hole of the servo valve (17) is connected to the oil return hole of the servo valve (4) through an oil pipe. The other end of the oil return hole of the servo valve (17) is connected to the oil outlet of the first oil return hole (110) through an oil pipe. One end of the external oil return hole (18) is connected to the oil drain hole of the servo valve (4) through an oil pipe. The other end of the external oil return hole (18) is connected to the oil inlet of the external oil supply equipment through an oil pipe.

5. The variable damping actively controlled extrusion film damper according to claim 4, characterized in that: The No. 1 oil passage (19) is an L-shaped oil passage. One end of the No. 1 oil passage (19) is connected to the side wall of the corresponding servo valve mounting block (11), and the other end of the No. 1 oil passage (19) is connected to the inner ring surface of the outer ring (1) of the damper. A sealing plug is provided on the end of the No. 1 oil passage (19) connected to the side wall of the servo valve mounting block (11).

6. The variable damping actively controlled extrusion film damper according to claim 5, characterized in that: Two No. 2 oil passage holes (22) are machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve (2). Each No. 2 oil passage hole (22) is connected to the No. 1 oil passage hole (19). Two No. 2 oil return hole groups are machined at equal intervals along the circumference on the outer ring surface of the tapered sleeve (2). Each No. 2 oil return hole group includes two No. 2 oil return holes (23). In each No. 2 oil return hole group, one No. 2 oil return hole (23) is connected to one oil return groove (13). Two No. 2 oil film pressure sensor mounting holes (24) are also machined on the outer ring surface of the tapered sleeve (2). Each No. 2 oil film pressure sensor mounting hole (24) is coaxially connected to one No. 1 oil film pressure sensor mounting hole (12).

7. The variable damping actively controlled extrusion film damper according to claim 6, characterized in that: Two sealing ring mounting grooves (21) are machined on the outer ring surface of the cone sleeve (2) along the axial direction of the cone sleeve (2), and the two sealing ring mounting grooves (21) are symmetrically arranged on both sides of the two No. 2 oil film pressure sensor mounting holes (24). Each sealing ring mounting groove (21) has a sealing ring, and the cone sleeve (2) is sealed with the outer ring (1) of the damper through the two sealing rings.

8. The variable damping actively controlled squeeze film damper according to claim 6, characterized in that: The outer circumference of the inner ring (3) of the squirrel cage is machined with an oil inlet ring groove (31) and two piston ring mounting grooves (32). The two piston ring mounting grooves (32) are symmetrically arranged on both sides of the oil inlet ring groove (31). The oil inlet ring groove (31) is connected to two No. 2 oil passage holes (22). Each piston ring mounting groove (32) is provided with a piston ring (7). The inner ring (3) of the squirrel cage is sealed with the cone sleeve (2) through the two piston rings (7).

9. The variable damping actively controlled extrusion film damper according to claim 5, characterized in that: The eddy current displacement sensor (6) is mounted on the front end of the damper outer ring (1) via an L-shaped mounting bracket. Two sets of eddy current displacement sensor mounting holes are machined on the front end face of the damper outer ring (1). Each set of eddy current displacement sensor mounting holes corresponds to a No. 1 oil film pressure sensor mounting hole (12). The vertical part of the L-shaped mounting bracket is mounted on the front end of the damper outer ring (1) by bolts and a set of eddy current displacement sensor mounting holes. The eddy current displacement sensor (6) is embedded in the horizontal part of the L-shaped mounting bracket.

10. A method for adjusting the variable damping of an actively controlled extrusion film damper based on any one of claims 1 to 9, characterized in that: The adjustment method is specifically implemented through the following steps: Step 1: Complete the installation of the specific rotor and the active control squeezing oil film damper; Step 2: The rotor begins to rotate, driving the squirrel cage inner ring (3) in the active control squeezing oil film damper to vortex; Step 3: As the inner ring (3) of the squirrel cage eddies, the oil film pressure sensor (5) begins to monitor the oil film pressure change between the inner ring (3) of the squirrel cage and the cone sleeve (2) in real time, and the eddy current displacement sensor (6) monitors the position change of the inner ring (3) of the squirrel cage in real time. The data acquisition system records the oil film pressure data and the eddy current displacement sensor data as feedback parameters. Step 4: When the eddy current displacement sensor (6) detects a change in the eddy position of the inner ring (3) of the squirrel cage, the servo valve (4) that is close to the eddy position of the inner ring (3) of the squirrel cage increases the oil supply pressure through the PLC control board, while the servo valve (4) that is far from the eddy position of the inner ring (3) of the squirrel cage supplies oil with a smaller oil supply pressure, thereby adjusting the real-time damping performance of the active control extrusion oil film damper in real time. Step 5: Verify the variable damping characteristics of the adjusted active control extrusion film damper to determine whether the above steps have achieved the expected effect of variable damping.

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