Trailing edge flap drive mechanism to adjust rotor cone and dynamic balance and control vibration

Abstract

The present invention belongs to the field of aerospace technology, and relates to a trailing edge flap drive mechanism for adjusting a rotor cone and dynamic balance and controlling vibration. The driver transmits high-frequency dynamic motion to the trailing edge flap through a push-pull rod, and drives the trailing edge flap to perform high-frequency dynamic deflection to change the aerodynamic load and aerodynamic-elastic coupling response of the blade. While the trailing edge flap is performing high-frequency dynamic deflection, the push-pull rod drives the trailing edge flap to change the initial deflection angle through the extension and contraction of a piston rod to change the aerodynamic load and elastic deformation of the blade. The trailing edge flap drive mechanism of the present invention can suppress the passing frequency vibration of the rotor when driving the trailing edge flap to perform high-frequency dynamic deflection. At the same time, the push-pull rod can change the initial deflection angle of the trailing edge flap to actively adjust the rotor cone and reduce the vibration load of the rotor.

Description

Technical Field

[0001] The invention belongs to the field of aerospace technology, and in particular relates to a trailing edge flap driving mechanism for adjusting a rotor cone and dynamic balance and controlling vibration. Background Art

[0002] Helicopters have the characteristics of efficient hovering and low-speed forward flight, and are widely used in military and civilian fields. However, the vibration level of helicopters is generally high, which not only affects the comfort of drivers and passengers, but also seriously affects the reliability of recording equipment and the fatigue life of the airframe structure. The rotor is one of the most important components of a helicopter and the main source of helicopter vibration. On the one hand, because the helicopter rotor works in a complex aerodynamic environment, it needs to face the airflow compression of the forward blades, the dynamic stall and reflow zone of the rearward blades, etc. when flying forward, which causes severe vibration loads on the blades. The vibration load is filtered through the hub to form kn b Ω(k is a positive integer, n b is the number of blades, Ω is the rotor rotation frequency) and is transmitted to the fuselage. On the other hand, due to the errors in the manufacturing and installation of the blades, as well as moisture and wear during use, there are certain differences in the mass and aerodynamic load of each blade, causing the rotor cone to be unbalanced, causing the rotor to generate 1Ω and other non-passing frequency vibration loads during rotation.

[0003] Trailing edge flap rotor is an effective active vibration control technology. The dynamic deflection of the trailing edge flap can actively change the aerodynamic load distribution and aerodynamic-elastic coupling response of the blade, thereby significantly suppressing the vibration of the rotor. Boeing and Sikorsky Helicopters have completed full-scale trailing edge flap rotor wind tunnel tests, while Eurocopter has completed flight tests of trailing edge flap rotors based on BK-117 and EC-145 helicopters, achieving a significant reduction in the vibration load of the rotor passing frequency. In China, institutions such as Nanjing University of Aeronautics and Astronautics and China Helicopter Design Institute have carried out research on trailing edge flap rotors, and have completed wind tunnel tests of scaled models of different sizes, achieving good vibration control effects.

[0004] Existing trailing edge flap rotor vibration control is mostly aimed at rotor passing frequency vibration, while there are relatively few studies on using trailing edge flaps to adjust the rotor cone to suppress the rotor 1Ω and other non-passing frequency vibration loads. The rotor cone adjustment of the current active helicopter models still generally adopts traditional methods such as changing the deflection angle of the trailing edge adjustment plate, the length of the pitch rod, and the blade tip counterweight, which is not only time-consuming and labor-intensive, but also difficult to achieve the optimal adjustment effect under different flight conditions. The deflection of the trailing edge flap can effectively change the rotor aerodynamic load, has the potential to adjust the rotor cone, and can dynamically adjust the rotor cone as the helicopter flight state changes, achieving the optimal adjustment effect under different flight conditions. For the existing trailing edge flap drive mechanism, directly using the driver to change the trailing edge flap neutral position to adjust the rotor cone will affect the effective output range of the driver, thereby reducing the control effect of the trailing edge flap on the passing frequency vibration load. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art, provide a trailing edge flap drive mechanism for adjusting the rotor cone and dynamic balance and controlling vibration, and solve the following problems:

[0006] The helicopter rotor has a vibration load at the passing frequency, and its frequency is usually an integer multiple of the rotor rotation frequency. In this case, the trailing edge flap needs to be dynamically deflected at a higher frequency to generate an additional aerodynamic load of the corresponding frequency to suppress the rotor passing frequency vibration;

[0007] Changing the initial deflection position of the trailing edge flap can change the aerodynamic load of the blade, thereby realizing the function of adjusting the rotor cone. Directly using the piezoelectric driver to control the initial deflection position of the trailing edge flap will reduce the dynamic output amplitude of the piezoelectric driver, thereby reducing the vibration control effect.

[0008] Traditional trailing edge flap support solutions mostly use radial bearings and thrust bearings. The bearing clearance will significantly affect the deflection movement of the trailing edge flap, and the strong centrifugal force during the rotation of the rotor will cause the bearing lubricant or grease to be thrown out, causing the deflection friction of the trailing edge flap to increase.

[0009] In order to achieve the purpose of the present invention, the present invention will be implemented by adopting the following technical solutions.

[0010] A trailing edge flap driving mechanism for adjusting rotor cone and dynamic balance and controlling vibration comprises a driver, a push-pull rod, a push-pull rod flexible hinge, a trailing edge flap, a fixing frame and a flap flexible hinge, wherein:

[0011] The fixing frame is arranged inside the blade;

[0012] The front end of the trailing edge flap is connected to the rear end of the fixed frame through a bearing;

[0013] The driver is arranged in the fixed frame, the front end of the driver is fixedly connected to the front frame of the fixed frame, and the rear end of the driver is fixedly connected to the fixed end of the push-pull rod capable of reciprocating in the center hole of the rear frame of the fixed frame;

[0014] The front end of the trailing edge flap is connected to the rear end of the fixed frame through a bearing and a flap flexible hinge; wherein the flap flexible hinge is used to limit the deflection angle of the trailing edge flap in high-frequency dynamic deflection around the fixed axis;

[0015] The piston rod of the push-pull rod is fixedly connected to the front end of the trailing edge flap through a push-pull rod flexible hinge; wherein the push-pull rod flexible hinge is used to reduce the bending moment brought to the push-pull rod by the movement of the trailing edge flap around the fixed axis;

[0016] The driver transmits the generated high-frequency dynamic motion to the trailing edge flap through the push-pull rod, driving the trailing edge flap to dynamically deflect at high frequency to change the aerodynamic load and aerodynamic-elastic coupling response of the blade, so as to actively control the passing frequency vibration of the rotor; while the trailing edge flap is dynamically deflected at high frequency, the push-pull rod can actively control the telescopic motion of the piston rod, driving the trailing edge flap to change the initial deflection angle to change the aerodynamic load and elastic deformation of the blade, so as to achieve active adjustment of the rotor cone and dynamic balance.

[0017] As a preferred solution of the present invention, the driver includes a piezoelectric stack and a displacement amplification frame, wherein the left and right ends of the displacement amplification frame are respectively fixedly connected to the left and right ends of the piezoelectric stack, the front end of the displacement amplification frame is fixedly connected to the front frame of the fixed frame, and the rear end of the displacement amplification frame is fixedly connected to the front end of the fixed end of the push-pull rod; wherein:

[0018] The piezoelectric stack is used to generate high-frequency vibrations;

[0019] The displacement amplification frame is used to change the direction of the high-frequency vibration generated by the piezoelectric stack and amplify the output as a dynamic linear displacement to be transmitted to the push-pull rod.

[0020] As a preferred embodiment of the present invention, the push-pull rod includes a fixed end, a piston rod, a piston sleeve, a nut, a driving gear, a motor, a first driven gear, a second driven gear, a thrust bearing, a rear cover, an angular contact bearing, a cylinder body and a screw shaft; wherein:

[0021] The shaft piece of the thrust bearing is fixedly connected to the front end of the screw shaft, and the seat piece of the thrust bearing is fixedly connected to the fixed end;

[0022] The output shaft of the motor and the shaft hole of the driving gear are interference fit;

[0023] The driving gear is meshed with a first driven gear arranged on the rear cover, the first driven gear is meshed with a second driven gear, and the shaft hole of the second driven gear is interference fit with the front end of the screw shaft;

[0024] The rear end of the rear cover is fixedly connected to the front end of the cylinder body;

[0025] The inner ring of the angular contact bearing is interference fit with the screw shaft, and the outer ring of the angular contact bearing is interference fit with the rear cover;

[0026] The nut is threadably matched with the screw shaft;

[0027] The threaded hole of the piston rod is threadably matched with the screw shaft, and the front end of the piston rod abuts against the rear end of the nut;

[0028] The outer wall of the piston sleeve is slidably matched with the inner wall of the cylinder body, and the inner wall of the piston sleeve is interference matched with the rear end of the nut and the front end of the piston rod.

[0029] As a preferred embodiment of the present invention, the connection structure between the front end of the trailing edge flap and the rear end of the fixed frame includes: a bearing, a flap pressing block, a fixed frame pressing block, a mounting platform, a bearing seat and a fixed shaft, wherein:

[0030] The rear end of the fixing frame is provided with the mounting platform;

[0031] The bearing seat is fixed on the outer side of the mounting platform, the bearing hole of the bearing seat is interference fit with the outer ring of the bearing, and the inner ring of the bearing is interference fit with the fixed shaft at the front end of the trailing edge flap;

[0032] The front end of the flap flexible hinge is fixed to the inner side of the mounting platform by the fixing frame pressing block, and the rear end of the flap flexible hinge is fixed to the front end of the trailing edge flap by the flap pressing block.

[0033] Beneficial effects: 1. By changing the length of the push-pull rod, the neutral position of the trailing edge flap can be adjusted independently relative to the driver, and the vibration control effect of the trailing edge flap will not be reduced due to affecting the effective output range of the driver, so that the trailing edge flap rotor has the ability to suppress the rotor passing frequency vibration load and the ability to adjust the rotor cone;

[0034] 2. Within the entire flight envelope, the push-pull rod length can be adjusted in real time, so as to achieve the optimal rotor cone adjustment effect under different flight conditions, and significantly suppress the rotor 1 / rev and other non-passing frequency vibration loads;

[0035] 3. Flexible hinges are used between the push-pull rod and the trailing edge flap, and between the trailing edge flap and the blade instead of the traditional mechanical hinges, avoiding the influence of the gap of the mechanical hinge on the deflection of the trailing edge flap, and simplifying the maintenance requirements and workload of the trailing edge flap drive mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0037] Figure 2 It is a schematic diagram of the drive components;

[0038] Figure 3 It is a schematic diagram of a fixed frame structure;

[0039] Figure 4 It is a schematic diagram of the trailing edge flap structure;

[0040] Figure 5 It is a cross-sectional view of a variable length push-pull rod;

[0041] Reference numerals:

[0042] 1. Driver; 2. Push-pull rod; 3. Push-pull rod flexible hinge; 4. Trailing edge flap; 5. Bearing; 6. Flap pressure block; 7. Fixed frame pressure block; 8. Mounting platform; 9. Fixed frame; 10. Displacement amplification frame; 11. Piezoelectric stack; 12. Bearing seat; 13. Flap flexible hinge; 14. Fixed shaft; 15. Fixed end; 16. Piston rod; 17. Piston sleeve; 18. Nut; 19. Driving gear; 20. Motor; 21. First driven gear; 22. Second driven gear; 23. Thrust bearing; 24. Rear cover; 25. Angular contact bearing; 26. Cylinder body; 27. Screw shaft. DETAILED DESCRIPTION

[0043] The present invention will be further described with reference to the accompanying drawings and embodiments.

[0044] As embodiment 1 of the present invention, Figures 1 to 5 As shown, a trailing edge flap drive mechanism for adjusting the rotor cone and dynamic balance and controlling vibration, the drive mechanism includes a driver 1, a push-pull rod 2, a push-pull rod flexible hinge 3, a trailing edge flap 4, a fixing frame 9 and a flap flexible hinge 13, wherein:

[0045] The fixing frame 9 is arranged inside the blade and is used to fix the driver;

[0046] The front end of the trailing edge flap 4 is connected to the rear end of the fixing frame 9 through a bearing 5;

[0047] The driver 1 is arranged in the fixed frame 9, the front end of the driver 1 is fixedly connected to the front frame of the fixed frame 9, and the rear end of the driver 1 is fixedly connected to the fixed end 15 of the push-pull rod 2 which can reciprocate in the center hole of the rear frame of the fixed frame 9;

[0048] The front end of the trailing edge flap 4 is connected to the rear end of the fixed frame 9 through a bearing 5 and a flap flexible hinge 13; wherein the flap flexible hinge 13 is used to limit the deflection angle of the trailing edge flap 4 around the fixed axis 14 during high-frequency dynamic deflection;

[0049] The piston rod 16 of the push-pull rod 2 is fixedly connected to the front end of the trailing edge flap 4 through the push-pull rod flexible hinge 3; wherein the push-pull rod flexible hinge 3 is used to reduce the bending moment brought to the push-pull rod by the movement of the trailing edge flap 4 around the fixed axis 14;

[0050] The driver 1 transmits the generated high-frequency dynamic motion to the trailing edge flap 4 through the push-pull rod 2, driving the trailing edge flap 4 to dynamically deflect at high frequency to change the aerodynamic load and aerodynamic-elastic coupling response of the blade, so as to actively control the passing frequency vibration of the rotor; while the trailing edge flap 4 is dynamically deflected at high frequency, the push-pull rod 2 can actively control the telescopic motion of its piston rod 16 to drive the trailing edge flap 4 to change the initial deflection angle to change the aerodynamic load and elastic deformation of the blade, so as to realize active adjustment of the rotor cone and dynamic balance.

[0051] As embodiment 2 of the present invention, Figure 1 and Figure 2 As shown, the driver 1 includes a piezoelectric stack 11 and a displacement amplification frame 10, wherein the left and right ends of the displacement amplification frame 10 are fixedly connected to the left and right ends of the piezoelectric stack 11 respectively, the front end of the displacement amplification frame 10 is fixedly connected to the front frame of the fixed frame 9, and the rear end of the displacement amplification frame 10 is fixedly connected to the front end of the fixed end 15 of the push-pull rod 2; wherein:

[0052] The piezoelectric stack 11 is used to generate high-frequency vibration;

[0053] The displacement amplification frame 10 is used to change the direction of the high-frequency vibration generated by the piezoelectric stack 11 and amplify the output as a dynamic linear displacement to be transmitted to the push-pull rod 2.

[0054] As embodiment 3 of the present invention, Figure 5 As shown, the push-pull rod 2 includes a fixed end 15, a piston rod 16, a piston sleeve 17, a nut 18, a driving gear 19, a motor 20, a first driven gear 21, a second driven gear 22, a thrust bearing 23, a rear cover 24, an angular contact bearing 25, a cylinder body 26 and a screw shaft 27; wherein:

[0055] The shaft piece of the thrust bearing 23 is fixedly connected to the front end of the screw shaft 27, and the seat piece of the thrust bearing 23 is fixedly connected to the fixed end 15;

[0056] The output shaft of the motor 20 is interference-fitted with the shaft hole of the driving gear 19;

[0057] The driving gear 19 is meshed with a first driven gear 21 provided on the rear cover 24, the first driven gear 21 is meshed with a second driven gear 22, and the shaft hole of the second driven gear 22 is interference fit with the front end of the screw shaft 27;

[0058] The rear end of the rear cover 24 is fixedly connected to the front end of the cylinder body 26;

[0059] The inner ring of the angular contact bearing 25 is interference fit with the screw shaft 27, and the outer ring of the angular contact bearing 25 is interference fit with the rear cover 24;

[0060] The nut 18 is threadedly matched with the screw shaft 27;

[0061] The threaded hole of the piston rod 16 is threadedly matched with the screw shaft 27, and the front end of the piston rod 16 abuts against the rear end of the nut 18;

[0062] The outer wall of the piston sleeve 17 is slidably matched with the inner wall of the cylinder body 26 , and the inner wall of the piston sleeve 17 is interference matched with the rear end of the nut 18 and the front end of the piston rod 16 .

[0063] As embodiment 4 of the present invention, Figures 1 to 4 As shown, the connection structure between the front end of the trailing edge flap 4 and the rear end of the fixed frame 9 includes: a bearing 5, a flap pressing block 6, a fixed frame pressing block 7, a mounting platform 8, a bearing seat 12 and a fixed shaft 14, wherein:

[0064] The rear end of the fixing frame 9 is provided with the mounting platform 8;

[0065] The bearing seat 12 is fixed on the outer side of the mounting platform 8, the bearing hole of the bearing seat 12 is interference fit with the outer ring of the bearing 5, and the inner ring of the bearing 5 is interference fit with the fixed shaft 14 at the front end of the trailing edge flap 4;

[0066] The front end of the flap flexible hinge 13 is fixed to the inner side of the mounting platform 8 by the fixing frame pressing block 7 , and the rear end of the flap flexible hinge 13 is fixed to the front end of the trailing edge flap 4 by the flap pressing block 6 .

[0067] As embodiment 5 of the present invention, Figures 1 to 5As shown, the driver 1 adopts a piezoelectric driver, which consists of a displacement amplification frame 10 and a piezoelectric stack 11. When the driving voltage increases, the piezoelectric stack 11 can be slightly extended. Under the displacement amplification effect of the displacement amplification frame 10, the output end of the driver 1 moves toward the fixed end, and the displacement amplification frame 10 stores elastic potential energy; when the driving voltage decreases, the displacement amplification frame 10, under the action of the elastic restoring force, makes the output end of the driver 1 move away from the fixed end; the dynamic reciprocating motion of the output end of the driver 1 can be realized by dynamically changing the driving voltage; the push-pull rod 2 is a screw nut structure, and the motor 20 drives the screw shaft 27 to rotate, thereby driving the nut 18, the piston 17 and the piston rod 16 to telescopic movement, and the telescopic direction not only has high rigidity, but also has self-locking ability, can withstand the external load applied by the driver 1 and the trailing edge flap 4 and keep its own length from passive deformation; the push-pull rod flexible hinge 3 and the flap flexible hinge 13 adopt a thin sheet structure of metal material or composite material, which has the characteristics of low bending rigidity and high shear strength.

[0068] As embodiment 6 of the present invention, Figure 1 and Figure 2 As shown, the drive mechanism provided by the present invention is applied to the connection and fixing scheme on the helicopter blade. Based on the drive mechanism, the fixing frame 9 is fixed to the blade by bonding and winding process, and provides a mounting platform 8 for fixing the driver 1 and the trailing edge flap 4. During the rotation of the rotor, the centrifugal load of the driver 1 and the push-pull rod 2 is transmitted to the fixing frame 9 through bolts and grooves at the fixed end of the driver 1, and then transmitted to the blade; the centrifugal load of the trailing edge flap 4 is transmitted to the mounting platform 8 of the fixing frame 9 through the shearing action of the flap flexible hinge 13, and then transmitted to the blade.

[0069] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A trailing edge flap drive mechanism for adjusting a rotor cone and dynamic balance and controlling vibration, the drive mechanism comprising a driver (1), a push-pull rod (2), a push-pull rod flexible hinge (3), a trailing edge flap (4), a fixing frame (9) and a flap flexible hinge (13), wherein: The fixing frame (9) is arranged inside the blade and is used to fix the driver; The front end of the trailing edge flap (4) is connected to the rear end of the fixed frame (9) via a bearing (5); The driver (1) is arranged in a fixed frame (9), the front end of the driver (1) is fixedly connected to the front frame of the fixed frame (9), and the rear end of the driver (1) is fixedly connected to the fixed end (15) of a push-pull rod (2) capable of reciprocating in a central hole of the rear frame of the fixed frame (9); Features: The front end of the trailing edge flap (4) is connected to the rear end of the fixed frame (9) via a bearing (5) and a flap flexible hinge (13); wherein the flap flexible hinge (13) is used to limit the deflection angle of the trailing edge flap (4) in high-frequency dynamic deflection around a fixed axis (14); The piston rod (16) of the push-pull rod (2) is fixedly connected to the front end of the trailing edge flap (4) via a push-pull rod flexible hinge (3); wherein the push-pull rod flexible hinge (3) is used to reduce the bending moment caused to the push-pull rod by the movement of the trailing edge flap (4) around the fixed axis (14); The driver (1) transmits the generated high-frequency dynamic motion to the trailing edge flap (4) via the push-pull rod (2), driving the trailing edge flap (4) to perform high-frequency dynamic deflection to change the aerodynamic load and aerodynamic-elastic coupling response of the blade, so as to actively control the passing frequency vibration of the rotor; while the trailing edge flap (4) is performing high-frequency dynamic deflection, the push-pull rod (2) can actively control the telescopic motion of the piston rod (16), driving the trailing edge flap (4) to change the initial deflection angle, so as to change the aerodynamic load and elastic deformation of the blade, so as to achieve active adjustment of the rotor cone and dynamic balance.

2. A trailing edge flap drive mechanism for adjusting rotor cone and dynamic balance and controlling vibration according to claim 1, characterized in that: The driver (1) comprises a piezoelectric stack (11) and a displacement amplification frame (10), wherein the left and right ends of the displacement amplification frame (10) are respectively fixedly connected to the left and right ends of the piezoelectric stack (11), the front end of the displacement amplification frame (10) is fixedly connected to the front frame of the fixed frame (9), and the rear end of the displacement amplification frame (10) is fixedly connected to the front end of the fixed end (15) of the push-pull rod (2); wherein: The piezoelectric stack (11) is used to generate high-frequency vibration; The displacement amplification frame (10) is used to change the direction of the high-frequency vibration generated by the piezoelectric stack (11) and amplify the output as a dynamic linear displacement to be transmitted to the push-pull rod (2).

3. A trailing edge flap drive mechanism for adjusting rotor cone and dynamic balance and controlling vibration according to claim 1, characterized in that: The push-pull rod (2) comprises a fixed end (15), a piston rod (16), a piston sleeve (17), a nut (18), a driving gear (19), a motor (20), a first driven gear (21), a second driven gear (22), a thrust bearing (23), a rear cover (24), an angular contact bearing (25), a cylinder body (26) and a screw shaft (27); wherein: The shaft piece of the thrust bearing (23) is fixedly connected to the front end of the screw shaft (27), and the seat piece of the thrust bearing (23) is fixedly connected to the fixed end (15); The output shaft of the motor (20) is interference-fitted with the shaft hole of the driving gear (19); The driving gear (19) meshes with a first driven gear (21) provided on the rear cover (24), the first driven gear (21) meshes with a second driven gear (22), and the shaft hole of the second driven gear (22) is interference-fitted with the front end of the screw shaft (27); The rear end of the rear cover (24) is fixedly connected to the front end of the cylinder body (26); The inner ring of the angular contact bearing (25) is in interference fit with the screw shaft (27), and the outer ring of the angular contact bearing (25) is in interference fit with the rear cover (24); The nut (18) is threadably matched with the screw shaft (27); The threaded hole of the piston rod (16) is threadably matched with the screw shaft (27), and the front end of the piston rod (16) abuts against the rear end of the nut (18); The outer wall of the piston sleeve (17) is slidably matched with the inner wall of the cylinder body (26), and the inner wall of the piston sleeve (17) is interference matched with the rear end of the nut (18) and the front end of the piston rod (16).

4. A trailing edge flap drive mechanism for adjusting rotor cone and dynamic balance and controlling vibration according to claim 1, characterized in that: The connection structure between the front end of the trailing edge flap (4) and the rear end of the fixed frame (9) comprises: a bearing (5), a flap pressing block (6), a fixed frame pressing block (7), a mounting platform (8), a bearing seat (12) and a fixed shaft (14), wherein: The rear end of the fixing frame (9) is provided with the mounting platform (8); The bearing seat (12) is fixed on the outside of the mounting platform (8), the bearing hole of the bearing seat (12) is interference fit with the outer ring of the bearing (5), and the inner ring of the bearing (5) is interference fit with the fixed shaft (14) at the front end of the trailing edge flap (4); The front end of the flap flexible hinge (13) is fixed to the inner side of the mounting platform (8) by means of the fixing frame pressing block (7), and the rear end of the flap flexible hinge (13) is fixed to the front end of the trailing edge flap (4) by means of the flap pressing block (6).

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