Self-locking dry friction damper for vibration control of aircraft engine rotors

Abstract

The present invention discloses a self-locking dry friction damper for vibration control of aircraft engine rotors, including a driving mechanism, a locking / unlocking mechanism, a damper housing, a dynamic contact disc, a static contact disc, a static contact disc flexible connection sleeve, a rolling bearing, a housing, a rotor shaft stand and a rotor shaft; the static contact disc flexible connection sleeve is fixedly mounted on the rotor shaft stand, the static contact disc flexible connection sleeve is connected to the static contact disc, and is mounted on the rotor shaft through a bearing; the housing is a round tube structure, the housing is fixedly connected to the static contact disc flexible connection sleeve; the dynamic contact disc is connected to the driving mechanism, the driving mechanism is mounted on the damper housing through a bracket, and the locking / unlocking mechanism is mounted on the damper housing corresponding to the driving mechanism. The present invention effectively solves the problem of a sharp decline in the life of piezoelectric ceramics due to severe heating caused by long-term operation, and meets the technical requirements of vibration control of aircraft engine rotors.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine vibration control devices, and in particular relates to a self-locking dry friction damper used for aircraft engine rotor vibration control. Background Art

[0002] The rotor system of an aircraft engine has a complex structure and operates in harsh environments such as high temperature, high pressure, high speed, and alternating loads for a long time. It is not only affected by factors such as airflow excitation, thermal deformation, and assembly structure failure of the engine itself, but its engine blades are also easily damaged by impact from foreign hard objects such as hail, metal fragments, and sand and dust during service. Engine rotor system imbalance, blade loss, and friction failures often occur, making the vibration problem of the engine rotor system particularly prominent. If it cannot be effectively controlled, it can cause serious engine safety accidents in a short period of time, resulting in significant economic losses.

[0003] Existing aircraft engines generally use squeeze film dampers to solve the problem of rotor system vibration control. Squeeze film dampers have a simple structure and good vibration reduction performance, but their oil film stiffness and damping are highly nonlinear. When the rotor eccentricity exceeds the limit, bistable, locked and uncoordinated precession are prone to occur, causing the rotor vibration to increase instead of decrease. In response to the nonlinear vibration problem of the oil film of the squeeze film damper, the elastic ring squeeze film damper divides the oil film into several inner and outer oil film cavities through an elastic ring, which can effectively reduce vibration and improve the nonlinear vibration problem of the oil film stiffness. However, there is currently a lack of corresponding dynamic characteristics of the oil film. Theoretical model, elastic ring processing is difficult and the service life cannot be effectively guaranteed; in recent years, the active vibration control method by introducing external damping has received widespread attention. The patent "An active elastic ring dry friction damper for a rotating mechanical rotor support structure (ZL201911026913.X)" proposes that an electromagnet or piezoelectric actuator drives the friction plate to realize the active vibration control of the rotor system. The patent "An intelligent structural elastic support dry friction damper (ZL201510873150.8)" combines the method of reentrant squirrel cage elastic support and piezoelectric ceramic driving friction plate to control the vibration of the rotor system when it is overcritical. The above two technical methods mainly have the following problems: 1) Piezoelectric actuators and piezoelectric ceramics are in a working state for a long time, and the heat generation is serious and cannot withstand the tensile force. The problem of failure due to heat and tensile load is very prominent, which greatly limits the service life of the damper. 2) Under the vibration excitation of complex frequency components of aircraft engines, the structural service life of elastic rings and reentrant squirrel cage elastic supports needs to be verified. 3) The rotor system of an aircraft engine has a compact structure and limited space. The use of electromagnets to drive friction plates makes the structure of the electromagnet actuator bulky. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a self-locking dry friction damper for vibration control of aircraft engine rotors, which can actively and quickly respond according to the real-time needs of rotor system vibration control, has the function of adjusting the damping capacity of the damper, realizes vibration control within the full speed range of the aircraft engine rotor, can lock and unlock the drive mechanism in time, and effectively solves the problem of severe heat generation due to long-term operation of piezoelectric ceramics, resulting in a sharp decline in lifespan, and meets the technical requirements of aircraft engine rotor vibration control for high life and high reliability of the damper.

[0005] The technical solution adopted by the present invention is: a self-locking dry friction damper for vibration control of aircraft engine rotors, comprising a driving mechanism, a locking / unlocking mechanism, a damper housing, a dynamic contact disc, a static contact disc, a flexible connecting sleeve of the static contact disc, a rolling bearing, a housing, a rotor shaft stand and a rotor shaft; the flexible connecting sleeve of the static contact disc is fixedly mounted on the rotor shaft stand, and the flexible connecting sleeve of the static contact disc is coaxially connected to the static contact disc; the flexible connecting sleeve of the static contact disc is mounted on the rotor shaft through a bearing; the housing is a circular tube structure, and the housing is fixedly connected to the flexible connecting sleeve of the static contact disc; the dynamic contact disc is arranged close to the static contact disc; the dynamic contact disc is connected to the driving mechanism, and the dynamic contact disc can contact the static contact disc under the action of the driving mechanism; the driving mechanism is mounted on the damper housing through a bracket, and the locking / unlocking mechanism is mounted on the damper housing corresponding to the driving mechanism, and can lock or unlock the dynamic contact disc.

[0006] In the above-mentioned self-locking dry friction damper for aircraft engine rotor vibration control, the shell includes an upper shell with a semi-circular cross-section and a lower shell with a semi-circular cross-section, a limit groove is provided on the cross-section of the lower shell, and a limit block is provided on the cross-section of the upper shell, and the limit block is placed in the limit groove; the lower shell and the upper shell are connected to form a tubular structure.

[0007] In the above-mentioned self-locking dry friction damper for controlling vibration of an aircraft engine rotor, an oil filling hole is provided on the upper shell.

[0008] In the above-mentioned self-locking dry friction damper for aircraft engine rotor vibration control, the dynamic contact disk is connected to four drive mechanisms, and the four drive mechanisms are evenly arranged along the circumferential direction; the drive mechanism includes a bracket, piezoelectric ceramics, a double hinge mechanism and a drive ring, the double hinge mechanism is a frame structure surrounded by two connecting plates and two hinge plates, the connecting plates are flat plates, the two connecting plates are arranged in parallel, the hinge plates are arc-shaped or obtuse-angle structures, and the angles of the hinge plate assemblies are arranged opposite to each other; a hinge is provided in the middle of the hinge plate; the two ends of the piezoelectric ceramics are respectively connected to the two connecting plates; the hinge of one hinge plate is fixedly connected to the damper housing through the bracket, and the hinge of the other hinge plate is connected to the dynamic contact disk through the drive ring.

[0009] In the above-mentioned self-locking dry friction damper for aircraft engine rotor vibration control, a locking / unlocking mechanism is respectively provided corresponding to the four driving mechanisms; the locking / unlocking mechanism includes a guide hole, a cover plate, an electromagnetic suction cup, a compression spring and an actuator slider; the guide hole is arranged on the damper housing, the actuator slider and the electromagnetic suction cup are placed in the guide hole, and the actuator slider and the guide hole are clearance-matched; the center line of the compression spring is perpendicular to the rotor shaft axis, one end of the compression spring contacts the electromagnetic suction cup, and the other end of the compression spring contacts the actuator slider, the electromagnetic suction cup is mounted on the cover plate, and the cover plate is mounted at the outer port of the guide hole, a plurality of equidistantly arranged rectangular protrusions are provided on the surface of the actuator slider facing the drive ring, and a plurality of equidistantly arranged rectangular grooves are provided on the surface of the drive ring facing the actuator slider; the spacing between adjacent rectangular protrusions is equal to the spacing between adjacent rectangular grooves.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] 1. The present invention is provided with a driving mechanism and a locking / unlocking mechanism. After the dynamic and static contact disks are in contact to achieve the vibration reduction effect, the driving mechanism can be self-locked through the cooperation of the driving ring and the execution slider, so that the piezoelectric ceramic can still maintain the vibration reduction function after the power is turned off. After the vibration reduction is completed, the driving mechanism is unlocked by the locking / unlocking mechanism, and the piezoelectric ceramic can reset itself, effectively solving the problem of a sharp decline in the life of the piezoelectric ceramic due to severe heating caused by long-term work. At the same time, the double hinge mechanism can amplify the output displacement of the piezoelectric ceramic, realize the function of adjusting the vibration reduction capacity of the present invention according to actual needs, and can also convert the direction of the output force of the piezoelectric ceramic to prevent it from being subjected to irreversible tensile force.

[0012] 2. The drive mechanism and locking / unlocking mechanism of the present invention have good assembly properties while ensuring sufficiently large vibration reduction capacity. At the same time, the present invention can be activated to reduce vibration at the early stage of a potential fault such as friction in the aircraft engine rotor to prevent the fault from rapidly deteriorating. In addition, when the rotor eccentricity exceeds the limit, the present invention and the oil film vibration reduction can work together, which greatly compensates for the problem of insufficient vibration reduction capacity caused by the nonlinearity of the oil film, so that the present invention can achieve vibration control within the full speed range of the aircraft engine rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the present invention.

[0014] Figure 2 It is a schematic structural diagram of the driving mechanism and the locking / unlocking mechanism of the present invention when it is in a non-working state.

[0015] Figure 3 for Figure 2 Enlarged view of point I in the middle.

[0016] Figure 4It is a schematic diagram of assembling the piezoelectric ceramic and double hinge mechanism of the present invention.

[0017] Figure 5 It is a schematic structural diagram of the driving mechanism and the locking / unlocking mechanism of the present invention when it is in a driving state.

[0018] Figure 6 It is a schematic structural diagram of the driving mechanism and the locking / unlocking mechanism of the present invention when they are in a locked state.

[0019] In the figure: 1 lower shell, 2 limiting groove, 3 rotor shaft, 4 rotor shaft stand, 5 static contact plate flexible connecting sleeve, 6 upper shell, 7 bearing, 8 oil filling hole, 9 static contact plate, 10 electromagnetic suction cup wire, 11 piezoelectric ceramic wire, 12 locking / unlocking mechanism, 13 dynamic contact plate, 14 driving mechanism, 15 damper shell, 16 damper stand.

[0020] 12-1 actuator slider, 12-2 compression spring, 12-3 electromagnetic suction cup, 12-4 cover plate, 14-1 bracket, 14-2 piezoelectric ceramic, 14-3 double hinge mechanism, 14-4 driving ring. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] like Figure 1 As shown, the present invention includes a shell, a limiting groove 2, a rotor shaft 3, a rotor shaft stand 4, a static contact disc flexible connecting sleeve 5, a rolling bearing 7, an oil filling hole 8, a static contact disc 9, an electromagnetic suction cup wire 10, a piezoelectric ceramic wire 11, a locking / unlocking mechanism 12, a dynamic contact disc 13, a driving mechanism 14, a damper shell 15 and a damper stand 16.

[0023] The flexible connection sleeve 5 of the static contact disc is fixedly mounted on the rotor shaft stand 4, and the flexible connection sleeve 5 of the static contact disc is coaxially connected with the static contact disc 9; the flexible connection sleeve 5 of the static contact disc is mounted on the rotor shaft 3 through the bearing 7 at the end facing the static contact disc 9. The shell comprises an upper shell 6 with a semi-circular cross section and a lower shell 1 with a semi-circular cross section, a limit groove 2 is provided on the cross section of the lower shell 1, and a limit block is provided on the cross section of the upper shell 6, and the limit block is placed in the limit groove 2 to achieve axial positioning between the upper shell 6 and the lower shell 1. The lower shell 1 and the upper shell 6 are connected to form a tubular structure by bolts. The upper shell 6 and the lower shell 1 are fixedly connected to the flexible connection sleeve 5 of the static contact disc and the rotor shaft stand 4 respectively by bolts. The upper shell 6 is provided with an oil filling hole 8 to ensure that the three parts of the flexible connection sleeve 5 of the static contact disc, the upper shell 6 and the lower shell 1 are filled with oil film. The dynamic contact disc 13 is arranged close to the static contact disc 9.

[0024] The moving contact plate 13 is connected to four driving mechanisms 14, and the four driving mechanisms 14 are evenly arranged along the circumferential direction. Figure 2 As shown, the driving mechanism 14 includes a bracket 14-1, a piezoelectric ceramic 14-2, a double hinge mechanism 14-3 and a driving ring 14-4. The right end of the double hinge mechanism 14-3 is connected to the bracket 14-1 by bolts, and the bracket 14-1 is fixed to the damper housing 15 by bolts. The left end of the double hinge mechanism 14-3 is fixedly connected to the driving ring 14-4, and the driving ring 14-4 is fixedly connected to the dynamic contact plate 13. The piezoelectric ceramic 14-2 is connected to the inner side of the double hinge mechanism 14-3 to achieve pre-tightening while protecting the piezoelectric ceramic to prevent it from being subjected to tensile force that may cause irreversible damage.

[0025] A locking / unlocking mechanism 12 is provided corresponding to each of the four driving mechanisms 14. Figure 2 and Figure 3 As shown, the locking / unlocking mechanism 12 includes a guide hole, a cover plate 12-4, an electromagnetic suction cup 12-3, a compression spring 12-2 and an execution slider 12-1; the guide hole is arranged on the damper housing, the execution slider 12-1 and the electromagnetic suction cup 12-3 are placed in the guide hole, and the execution slider 12-1 is in clearance with the guide hole. The center line of the compression spring 12-2 is perpendicular to the axis of the rotor shaft 3, one end of the compression spring 12-2 is in contact with the electromagnetic suction cup 12-3, and the other end of the compression spring 12-2 is in contact with the execution slider 12-1. The electromagnetic suction cup 12-3 is mounted on the cover plate 12-4, and the cover plate 12-4 is mounted at the outer port of the guide hole. A plurality of equidistantly arranged rectangular protrusions are provided on the surface of the execution slider 12-1 facing the drive ring 14-4, and a plurality of equidistantly arranged rectangular grooves are provided on the surface of the drive ring 14-4 facing the execution slider 12-1; the spacing between adjacent rectangular protrusions is equal to the spacing between adjacent rectangular grooves, and the rectangular protrusions can be embedded in the rectangular grooves, and their contact state is as shown in FIG. Figure 3 As shown. The actuator slider 12-1 contacts or separates with the drive ring 14-4 according to actual needs, ensuring that the present invention has a sufficiently large vibration reduction capacity and good assembly performance. The wire 11 of the drive mechanism 14 and the wire 10 of the locking / unlocking mechanism 12 are directly led out through holes punched in the damper housing 15.

[0026] Under the action of the driving mechanism 14, the dynamic contact disk 13 can contact the static contact disk 9. When a vibration fault with a small amplitude but great potential harm such as rubbing occurs in the rotor system of the aircraft engine, the present invention can be activated to reduce vibration. When an eccentricity exceeding limit fault occurs in the rotor system, part of the vibration mechanical energy of the rotor shaft 3 is dissipated through oil film vibration reduction, and the other part of the vibration mechanical energy is dissipated through friction heat energy between the dynamic contact disk 13 and the static contact disk 9.

[0027] The double hinge mechanism 14-3 is a frame structure surrounded by two connecting plates and two hinge plates. The connecting plates are flat plates, and the two connecting plates are arranged in parallel. The hinge plates are arc-shaped or obtuse-angle structures, and the angles of the hinge plate assemblies are arranged opposite to each other. The hinge plates are provided with long grooves arranged along the center line of the hinge plates. A hinge is provided in the middle of the hinge plates for connecting the bracket 14-1 or the drive ring 14-4. The two ends of the piezoelectric ceramic 14-2 are connected to the two connecting plates respectively. Its output displacement is related to the length, width, thickness, inclination angle, elastic modulus, axial stiffness, rotational stiffness, piezoelectric ceramic structure size and elastic constant of its own hypotenuse. The structure is as follows: Figure 4 As shown, the double hinge mechanism 14-3 can not only amplify the output displacement of the piezoelectric ceramic to facilitate the locking and unlocking functions and the adjustment of the vibration reduction capacity of the present invention, but also convert the direction of the output force of the piezoelectric ceramic, thereby protecting the piezoelectric ceramic from the tensile force that may cause irreversible damage.

[0028] When the present invention is in a non-working state, Figure 2 , 3 As shown, the piezoelectric ceramic 14-2 and the electromagnetic suction cup 12-3 are not energized, the dynamic contact plate 13 and the static contact plate 9 maintain a certain distance, and the compression spring 12-2 generates pressure on the actuator slider 12-1, so that the series of convex micro-rectangular grooves at the lower end of the actuator slider 12-1 are precisely matched with the series of concave micro-rectangular grooves on the plane of the driving ring 14-4, and there is a certain initial gap between the upper end of the actuator slider 12-1 and the electromagnetic suction cup 12-3.

[0029] like Figure 5 As shown, when the present invention is in a driving state, if a potentially harmful fault such as friction in the rotor system or a rotor eccentricity exceeding the limit fault is detected and the present invention needs to be started, the electromagnetic suction cup 12-3 is first energized, and the execution slider 12-1 overcomes the compression spring 12-2 and moves upward to fit the electromagnetic suction cup 12-3 under the suction force of the electromagnetic suction cup 12-3, and then different types of voltage signals are sent to the piezoelectric ceramic 14-2 according to the vibration reduction requirements of the rotor system fault, so that the piezoelectric ceramic 14-2 expands and drives the moving contact disk 13 to move to the left and fit the static contact disk 9. The static contact disk 9 rubs against the moving contact disk 13 under the excitation of the rotor, and dissipates the vibration mechanical energy in the form of frictional heat energy to achieve the purpose of vibration reduction.

[0030] like Figure 6As shown, when the present invention is in a locked state, because the piezoelectric ceramic 14-2 is prone to failure due to heat generation due to long-term operation, the drive mechanism 14 needs to be locked after the moving contact disk 13 and the static contact disk 9 are fitted together. First, the electromagnetic suction cup 12-3 is powered off, and the execution slider 12-1 automatically resets under the pressure of the compression spring 12-2. The drive ring 14-4 with a rectangular groove and the execution slider 12-1 with a rectangular protrusion are precisely matched again to achieve locking. The driving voltage signal of the piezoelectric ceramic 14-2 is canceled, and the present invention is still in a normal working state. When the vibration reduction demand of the rotor system ends, it is only necessary to power on the electromagnetic suction cup 12-3, and the execution slider 12-1 is lifted upward under the suction force of the electromagnetic suction cup 12-3. The moving contact disk 13 can be separated from the static contact disk 9 under the natural pulling force of the double hinge mechanism 14-3. Finally, the electromagnetic suction cup 12-3 is powered off to restore the present invention to the state as shown. Figure 2 Non-operating state shown.

Claims

1. A self-locking dry friction damper for vibration control of an aircraft engine rotor, characterized in that: It includes a driving mechanism, a locking / unlocking mechanism, a damper housing, a dynamic contact disc, a static contact disc, a flexible connecting sleeve of the static contact disc, a rolling bearing, a housing, a rotor shaft stand and a rotor shaft; the flexible connecting sleeve of the static contact disc is fixedly mounted on the rotor shaft stand, and the flexible connecting sleeve of the static contact disc is coaxially connected to the static contact disc; the flexible connecting sleeve of the static contact disc is mounted on the rotor shaft through a bearing; the housing is a circular tube structure, and the housing is fixedly connected to the flexible connecting sleeve of the static contact disc; the dynamic contact disc is arranged close to the static contact disc; the dynamic contact disc is connected to the driving mechanism, and the dynamic contact disc can contact the static contact disc under the action of the driving mechanism; the driving mechanism is mounted on the damper housing through a bracket, and the locking / unlocking mechanism is mounted on the damper housing corresponding to the driving mechanism, and can lock or unlock the dynamic contact disc; The shell comprises an upper shell with a semi-circular cross section and a lower shell with a semi-circular cross section, a limit groove is provided on the cross section of the lower shell, a limit block is provided on the cross section of the upper shell, and the limit block is placed in the limit groove; the lower shell and the upper shell are connected to form a tubular structure; The moving contact disk is connected to four driving mechanisms, and the four driving mechanisms are evenly arranged along the circumferential direction; the driving mechanism includes a bracket, a piezoelectric ceramic, a double hinge mechanism and a driving ring, the double hinge mechanism is a frame structure surrounded by two connecting plates and two hinge plates, the connecting plates are flat plates, the two connecting plates are arranged in parallel, the hinge plates are arc-shaped or obtuse-angle structures, and the angles of the hinge plate assemblies are arranged opposite to each other; a hinge is provided in the middle of the hinge plate; the two ends of the piezoelectric ceramic are respectively connected to the two connecting plates; the hinge of one hinge plate is fixedly connected to the damper housing through the bracket, and the hinge of the other hinge plate is connected to the moving contact disk through the driving ring; A locking / unlocking mechanism is provided corresponding to each of the four driving mechanisms; the locking / unlocking mechanism comprises a guide hole, a cover plate, an electromagnetic suction cup, a compression spring and an execution slider; the guide hole is arranged on the damper housing, the execution slider and the electromagnetic suction cup are placed in the guide hole, and the execution slider and the guide hole are clearance-matched; the center line of the compression spring is perpendicular to the rotor shaft axis, one end of the compression spring contacts the electromagnetic suction cup, and the other end of the compression spring contacts the execution slider, the electromagnetic suction cup is mounted on the cover plate, and the cover plate is mounted on the outer port of the guide hole, a plurality of equidistantly arranged rectangular protrusions are provided on the surface of the execution slider facing the drive ring, and a plurality of equidistantly arranged rectangular grooves are provided on the surface of the drive ring facing the execution slider; the spacing between adjacent rectangular protrusions is equal to the spacing between adjacent rectangular grooves.

2. The self-locking dry friction damper for aircraft engine rotor vibration control according to claim 1, characterized in that: The upper shell is provided with an oil filling hole.

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