Seesaw type propeller hub structure

Abstract

The utility model relates to a seesaw type propeller hub structure which comprises a base, a propeller clamp and a propeller blade, a main shaft and an amplitude limiting shaft are arranged in the middle of the propeller clamp, the main shaft penetrates through the amplitude limiting shaft, a main propeller bolt is arranged between the propeller clamp and the propeller blade, a gasket is arranged on the outer wall of the main propeller bolt, a balance weight is arranged on the outer surface of the upper end of the propeller clamp, and a balance weight bolt is arranged in the middle of the balance weight. Paddle bushings are arranged in the middles of the paddles, nuts are in threaded connection with the outer walls of the main paddle bolts, cotter pins are arranged in the middles of the main paddle bolts, and power bolts are arranged at the bottom of the base. According to the utility model, the flapping amplitude relative to the rotor propeller shaft is reduced through the variable pitch-flapping coupling, the transient flapping and the steady flapping relative to the propeller shaft are reduced, the flapping function and the variable pitch function are integrated at one hinge point, the number of parts is reduced, and the overall structure is simplified; due to the fact that parts are reduced, the overall weight is lighter, manufacturing is easy, meanwhile, the number of movable parts is smaller, and the reliability and maintainability of a system can be improved.

Description

Technical Field

[0001] This utility model relates to the field of propeller aircraft technology, and in particular to a seesaw-type propeller hub structure. Background Technology

[0002] A propeller aircraft is an aircraft that generates thrust by using a propeller. A propeller is a device that converts the rotational power of an engine into thrust by rotating blades in the air. A propeller usually consists of several blades and a central hub. When the propeller is driven to rotate by the output shaft of the engine, the inclined surfaces of the blades push the air backward, thereby generating a reaction force, i.e., thrust.

[0003] The seesaw rotor hub is a semi-articulated rotor hub design that is widely used in light helicopters and some drones, but existing seesaw rotor hubs have certain inconveniences in use.

[0004] First, existing seesaw-type propellers are mostly of unlimited or limited configurations during use. However, the limited configuration cannot mitigate the problem of rigid collisions between the blades and the limit during the flapping process. Furthermore, when the aircraft is in the horizontal cruise phase, the propeller speed decreases while the aircraft speed increases. The advancing and retreating blades are subjected to different incoming flow velocities, causing the blades to flap. The centrifugal force of the blades cannot overcome the flapping, and the blades are subjected to periodic alternating loads, which will exacerbate the fatigue damage of the blades. At the same time, the aerodynamic changes caused by the flapping will generate unbalanced torques on the aircraft, affecting the stability of the flight attitude.

[0005] Therefore, we propose a seesaw-type propeller hub structure. Utility Model Content

[0006] In view of the existing technology, the existing seesaw-type propellers are mostly of unlimited and limited position structures. However, the limited position structure cannot mitigate the problem of rigid collision between the blades and the limit during the blade flapping process. In addition, when the aircraft is in the horizontal cruise phase, the lift propeller speed decreases while the aircraft speed increases. The leading and trailing blades are subjected to different incoming flow velocities, causing the blades to flap and easily resulting in insufficient lift. This utility model provides a seesaw-type propeller hub structure.

[0007] The technical solution adopted by this utility model is: a seesaw-type propeller hub structure, including a base, a propeller clamp, and a propeller blade. A main shaft and a limiting shaft are provided in the middle of the propeller clamp, the main shaft passes through the limiting shaft, a main propeller bolt is provided between the propeller clamp and the propeller blade, a washer is provided on the outer wall of the main propeller bolt, a counterweight is provided on the upper outer surface of the propeller clamp, a counterweight bolt is provided in the middle of the counterweight, a propeller blade bushing is provided in the middle of the propeller blade, a nut is threadedly connected to the outer wall of the main propeller bolt, a cotter pin is provided in the middle of the main propeller bolt, a power bolt is provided at the bottom of the base, a bolt bushing is provided between the power bolt and the base, and a fuse is fixedly connected to the outer wall of the power bolt.

[0008] Furthermore, both ends of the main shaft are provided with end locking screws on their outer surfaces, the outer walls of the end locking screws are provided with end washers, and an elastic sleeve is provided between the limiting shaft and the propeller clamp.

[0009] Furthermore, the elastic sleeve includes an outer ring, an inner ring, and an elastic damper, with the inner ring located inside the outer ring and the elastic damper fixed between the outer ring and the inner ring.

[0010] Furthermore, the outer wall of the main shaft is provided with a main shaft bushing and a main shaft sleeve, the main shaft bushing is located on one side of the main shaft sleeve, and a bearing is provided between the main shaft and the propeller clamp.

[0011] Furthermore, the propeller clamp has a counterweight bolt hole and a propeller bolt hole in the middle, the counterweight bolt hole is located on one side of the propeller bolt hole, and the propeller clamp has an elastic sleeve hole inside.

[0012] Furthermore, the base has a power bolt hole at its bottom and a limiting hole and a bearing hole on its outer wall, with the limiting hole located on one side of the bearing hole.

[0013] Furthermore, both the limiting shaft and the elastic sleeve have a central hole in their middle portions, and the central hole of the limiting shaft and the central hole of the elastic sleeve have their axes coincident.

[0014] The beneficial effects of this utility model are:

[0015] In this invention, the flapping amplitude relative to the rotor shaft is reduced by variable pitch-flapping coupling, thereby reducing both transient and steady-state flapping relative to the rotor shaft.

[0016] Integrating the waving and pitch-changing functions into a single hinge point reduces the number of parts and simplifies the overall structure; due to the reduction in parts, the overall weight is lighter and easier to manufacture, while fewer moving parts improve the system's reliability and maintainability;

[0017] The rotor clip is designed with a pre-cone angle, which allows the rotor blades to better utilize airflow during rotation, reduce blade flapping motion, and improve the rotor's lift coefficient and efficiency. To a certain extent, it can alleviate the stress on the rotor blades during flight, reduce the bending moment and alternating stress at the blade root, reduce blade fatigue, and extend service life. The pre-cone angle also helps maintain better stability and maneuverability under different flight conditions.

[0018] The suspension height of the propeller clip is at the same height as the center of mass of the propeller blade, which effectively reduces the stress level of the propeller blade in the oscillation direction and the vibration level of the whole machine.

[0019] The compensating torque generated by the elastic sleeve can adjust the constraint stiffness of the blade flapping, which helps to ensure stability during flight. Appropriate constraint stiffness can improve the aerodynamic efficiency of the rotor and generate stable lift and thrust. The forces on the blades are more even during flight, reducing the risk of structural fatigue and damage and extending the service life of the structure.

[0020] The lateral swing angle of the elastic bushing is affected by the length-to-diameter ratio of the structure itself. Different blade swing angles and constraint stiffness can be obtained through design, which solves the problem that the swing angle of the existing seesaw cannot be limited or can be limited but there is rigid collision between the limits.

[0021] Surface contact ball bearings and flange bushings have better load-bearing capacity, reduce wear, and increase propeller life. Similarly, elastic bearings also have good shock absorption performance, which can effectively absorb the vibration and impact generated by rotor rotation, extend the vibration and impact generated by rotor system rotation, and at the same time have a certain degree of flexibility to adapt to small deformations and displacements under different working conditions. Moreover, they do not require frequent lubrication or other maintenance measures during use. Attached Figure Description

[0022] Figure 1 This is an overall structural diagram of the present invention;

[0023] Figure 2 This is a cross-sectional structural diagram of the limiting shaft of this utility model;

[0024] Figure 3 This is a cross-sectional structural diagram of the main shaft of this utility model;

[0025] Figure 4 This is a structural diagram of the propeller clip of this utility model;

[0026] Figure 5 This is a structural diagram of the base of this utility model;

[0027] Figure 6 This is a structural diagram of the elastic sleeve of this utility model.

[0028] The markings in the diagram are as follows: 1. Base; 2. Propeller clamp; 3. Propeller blade; 4. Main shaft; 5. Blowout limiting shaft; 6. Main propeller bolt; 7. Washer; 8. Counterweight; 9. Counterweight bolt; 10. Propeller blade bushing; 11. Nut; 12. Cotter pin; 13. Power bolt; 14. Bolt bushing; 15. Fuse; 16. End locking screw; 17. End washer; 18. Elastic sleeve; 181. Outer ring; 182. Inner ring; 183. Elastic damping; 19. Main shaft bushing; 20. Main shaft sleeve; 21. Bearing; 22. Counterweight bolt hole; 23. Propeller blade bolt hole; 24. Elastic sleeve hole; 25. Power bolt hole; 26. Blowout limiting hole; 27. Bearing hole. Detailed Implementation

[0029] In the description of this utility model, it should be noted that the terms "front", "up", "down", "left", "right", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] The following is in conjunction with the appendix Figures 1-6 The present invention will be further described below.

[0032] In order to solve the problems existing in the background technology, this application proposes the following technical solution: a seesaw type propeller hub structure.

[0033] The specific technical solution includes a base 1, a propeller clamp 2, and a propeller blade 3. A main shaft 4 and a limiting shaft 5 are located in the middle of the propeller clamp 2, with the main shaft 4 passing through the limiting shaft 5. A main propeller bolt 6 is located between the propeller clamp 2 and the propeller blade 3. A washer 7 is located on the outer wall of the main propeller bolt 6. A counterweight 8 is located on the upper outer surface of the propeller clamp 2, and a counterweight bolt 9 is located in the middle of the counterweight 8. A propeller bushing 10 is located in the middle of the propeller blade 3. A nut 11 is threaded onto the outer wall of the main propeller bolt 6, and a cotter pin 12 is located in the middle of the main propeller bolt 6. The bottom of the base 1... A power bolt 13 is provided, and a bolt bushing 14 is provided between the power bolt 13 and the base 1. A fuse 15 is fixedly connected to the outer wall of the power bolt 13. The base 1 mainly transmits the power output of the motor (engine) to drive the rotor to rotate and transmits the lift generated by the rotation of the rotor to the fuselage. The bottom of the base 1 is connected to the rotor of the power motor or the output shaft of the engine by bolts. The top of the base 1 has four lugs, two of which are opposite to each other and are fitted with bearings 21 and connected to the main shaft 4. The other two opposite lugs are fitted with limiting shafts 5.

[0034] Furthermore, end locking screws 16 are provided on the outer surfaces of both ends of the main shaft 4, and end washers 17 are provided on the outer walls of the end locking screws 16. An elastic sleeve 18 is provided between the limiting shaft 5 and the propeller clamp 2. The elastic sleeve 18 includes an outer ring 181, an inner ring 182, and an elastic damper 183. The inner ring 182 is located inside the outer ring 181, and the elastic damper 183 is fixedly installed between the outer ring 181 and the inner ring 182. The elastic sleeve 18 is composed of the inner ring 182, the outer ring 181, and the elastic damper 183 in the middle. The elastic sleeve 18 has radial, axial, torsional, and lateral deflection functions. The elastic sleeve 18 has an opening in the middle, but still has radial and lateral deflection characteristics. This design mainly utilizes the lateral deflection characteristics of the elastic sleeve 18. The elastic body of the elastic sleeve 18 can be freely designed to meet the constraint stiffness under different conditions.

[0035] Furthermore, both the limiting shaft 5 and the elastic sleeve 18 have a central hole in the middle, and the central hole of the limiting shaft 5 and the central hole of the elastic sleeve 18 have their axes coincident.

[0036] Reference Figure 3 , Figure 4 and Figure 5As shown, the outer wall of the main shaft 4 is provided with a main shaft bushing 19 and a main shaft sleeve 20. The main shaft bushing 19 is located on one side of the main shaft sleeve 20. A bearing 21 is provided between the main shaft 4 and the propeller clamp 2. The middle part of the propeller clamp 2 is provided with a counterweight bolt hole 22 and a blade bolt hole 23. The counterweight bolt hole 22 is located on one side of the blade bolt hole 23. An elastic sleeve hole 24 is opened inside the propeller clamp 2. A power bolt hole 25 is provided at the bottom of the base 1. The outer wall of the base 1 is provided with a limiting hole 26 and a bearing hole 27. The limiting hole 26 is located on one side of the bearing hole 27. The propeller clamp 2 mainly bears the centrifugal force of the rotor rotation and transmits the lift to the base 1. An elastic sleeve 18 is installed inside the propeller clamp 2. A limiting shaft 5 is installed inside the elastic sleeve 18 and passes through the lug hole of the base 1. The two components are installed in the middle of the lugs of the base 1 and connected to the base 1 via the main shaft 4. The main shaft 4 passes through the elastic sleeve 18 and the limiting shaft 5. The propeller clamp 2 and the base 1 are positioned in the axial direction of the main shaft 4 by the sleeve. The two ends of the propeller clamp 2 are bolted to the propeller blades 3. The structure at the connection position between the propeller clamp 2 and the propeller blades 3 is designed with a pre-cone angle. The structure of the propeller clamp 2 itself ensures that the axis of the main shaft 4 and the center of mass of the propeller blades 3 are at the same height. A counterweight 8 is installed on the propeller clamp 2. The main shaft 4 is installed between a pair of lug holes in the base 1. The main shaft 4 is sequentially equipped with a first bearing, a first sleeve, the propeller clamp 2, a second sleeve, a second bearing, a shaft end washer, and a shaft end locking screw. The centering and positioning of the propeller clamp 2 is achieved by the sleeve. A peelable adjustable washer is designed between the sleeve and the propeller clamp 2. The positioning of the propeller clip 2 is adjusted accordingly. The load of the rotor rotation can be converted into axial and radial loads along the main shaft 4, as well as circumferential rotation. The axial load is transmitted to the sleeve, bearing 21, and base 1 through the propeller clip 2. The radial load is borne by the main shaft 4. The circumferential rotation is achieved by the movement of the inner and outer rings of the bearings 21 at both ends. The limiting shaft 5 is installed between the other pair of lug holes of the base 1. The limiting shaft 5 passes through the inner ring 182 of the elastic sleeve 18. The axis of the central hole of the limiting shaft 5 coincides with the axis of the central hole of the elastic sleeve 18 to avoid structural interference with the main shaft 4. The main shaft 4 can pass through the central hole. The axis of the limiting shaft 5 can be arranged at any angle in space with the axis of the main shaft 4, but considering that the compensating torque generated by the elastic sleeve 18 is the actual effect of limiting the circumferential swing of the main shaft 4, Ideally, the axis of the limiting shaft 5 should be perpendicular to the axis of the main shaft 4. Alternatively, if the spatial structure makes it impossible for the axes of the limiting shaft 5 and the main shaft 4 to be in the same plane, the axis of the limiting shaft 5 can be translated. However, the lateral deflection of the elastic sleeve 18 will cause displacement. A parallelogram mechanism can be used, i.e., adding a connecting rod to prevent the elastic sleeve 18 from displacing, which can achieve the same effect. The first bearing and the second bearing are respectively installed in a pair of lug holes in the base 1, and are positioned radially through the hole-shaft fit, and axially through the shoulder and sleeve. The pair of bearings 21 are used together to mainly bear the lift of the rotor system and the torque generated by rotation. The bearings 21 need to bear radial load and axial load. The preferred bearings are elastic bearings 21, surface contact radial joint bearings 21, and flange bushings.

[0037] To ensure that those skilled in the art can fully understand the technical solution, this application provides the following overall overview:

[0038] When the propeller blades flap, the propeller clamp oscillates around the main shaft. The outer ring of the elastic sleeve inside the propeller clamp oscillates along with the propeller clamp. Since the inner ring of the elastic sleeve is connected to the limiting shaft, and the limiting shaft is connected to the base and does not oscillate, the inner and outer rings of the elastic sleeve deflect laterally. The deformation of the elastic sleeve generates a compensating torque, which can adjust the constraint stiffness of the propeller blade flapping. The propeller clamp flapping motion stops when the elastic sleeve can no longer deflect laterally, thus preventing excessive propeller blade flapping. Mechanical limit switches can also be added to prevent excessive propeller blade flapping. The bearing is installed in the hole at the top of the fixed base and mainly bears the load and bending moment caused by the propeller rotation. Surface contact type spherical bearings or flange bushings are preferred, as they have better axial load and bending moment bearing capacity than deep groove ball bearings. Elastic bearings can also be selected. Compared with sliding bearings and rolling bearings, they do not require lubrication, reducing maintenance. At the same time, elastic bearings have no metal contact and friction, resulting in a longer service life and enhanced corrosion resistance, which also improves the reliability of the system in harsh environments.

[0039] All standard parts used in this utility model can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art. In addition, the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0040] Although embodiments of the present invention have been shown and described, the scope of the present invention will be defined by the appended claims and their equivalents for those skilled in the art.

Claims

1. A seesaw paddle hub structure, characterized by, The utility model provides a kind of paddle, including base (1), paddle clamp (2) and paddle blade (3), the middle part of paddle clamp (2) is provided with main shaft (4) and limit amplitude shaft (5), main shaft (4) penetrates limit amplitude shaft (5), paddle clamp (2) and paddle blade (3) between being provided with main paddle bolt (6), the outer wall of main paddle bolt (6) is provided with washer (7), the upper end outer surface of paddle clamp (2) is provided with counterweight (8), the middle part of counterweight (8) is provided with counterweight bolt (9), the middle part of paddle blade (3) is provided with paddle blade bushing (10), the outer wall of main paddle bolt (6) is threadedly connected with nut (11), the middle part of main paddle bolt (6) is provided with split pin (12), the bottom of base (1) is provided with power bolt (13), power bolt (13) and base (1) between being provided with bolt bushing (14), the outer wall of power bolt (13) is fixedly connected with fuse (15).

2. A seesaw paddle hub structure according to claim 1, characterized in that, The outer surface of both ends of main shaft (4) is provided with end locking screw (16), the outer wall of end locking screw (16) is provided with end washer (17), limit amplitude shaft (5) and paddle clamp (2) between being provided with elastic sleeve (18).

3. A seesaw paddle hub structure according to claim 2, characterized in that The elastic sleeve (18) includes outer ring (181), inner ring (182) and elastic damping (183), the inner ring (182) is located inside the outer ring (181), and the elastic damping (183) is fixed between the outer ring (181) and the inner ring (182).

4. A seesaw paddle hub structure according to claim 1, characterized in that, The outer wall of main shaft (4) is provided with main shaft bushing (19) and main shaft sleeve (20), the main shaft bushing (19) is located on one side of the main shaft sleeve (20), and the main shaft (4) and the paddle clamp (2) are provided with bearing (21).

5. A seesaw paddle hub structure according to claim 1, characterized in that, The middle part of paddle clamp (2) is provided with counterweight bolt hole (22) and paddle bolt hole (23), the counterweight bolt hole (22) is located on one side of the paddle bolt hole (23), and the elastic sleeve hole (24) is formed in the paddle clamp (2).

6. A seesaw paddle hub structure according to claim 1, characterized in that, The bottom of base (1) is provided with power bolt hole (25), the outer wall of base (1) is provided with limit amplitude hole (26) and bearing hole (27), and the limit amplitude hole (26) is located on one side of the bearing hole (27).

7. A seesaw paddle hub structure according to claim 2, characterized in that, The middle part of limit amplitude shaft (5) and elastic sleeve (18) is provided with a hole, and the hole axis of limit amplitude shaft (5) coincides with that of elastic sleeve (18).

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