Hub assembly, propeller, aircraft

Abstract

This utility model discloses a propeller hub assembly, a propeller, and an aircraft, relating to the field of propeller technology. The propeller hub assembly includes a mounting base, a propeller hub, and a flapping hinge. The mounting base is driven and connected to the output end of a power unit. The end of the propeller hub has two mounting positions for mounting the propeller blades, distributed along a first direction. The propeller hub is mounted on the mounting base via the flapping hinge. A reference straight line is obtained by rotating the first direction along the rotation direction of the propeller hub by an included angle θ. The axis of the flapping hinge is parallel to the reference straight line, and the included angle θ ranges from 10° to 80°. The technical solution provided by this utility model can reduce the cruise drag of the propeller.

Description

Technical Field

[0001] This utility model relates to the field of propeller technology, and in particular to a hub assembly, a propeller, and an aircraft. Background Technology

[0002] In related technologies, semi-rigid rotor hubs used in aircraft typically incorporate flapping hinges and pitch hinges, utilizing cyclic pitch mechanisms to control the blade pitch angle, thereby controlling the magnitude and direction of the rotor's aerodynamic forces. Current semi-rigid rotor hubs, due to the large flapping amplitude of the blades, necessitate that the propeller be positioned high during the design phase—that is, far from the aircraft fuselage—to avoid collisions during flapping. This greater distance results in higher cruise drag for the propeller. Utility Model Content

[0003] The main objective of this invention is to provide a hub assembly, a propeller, and an aircraft designed to reduce the propeller's cruise drag.

[0004] To achieve the above objectives, the present invention proposes a rotor hub assembly for use in the propeller of an aircraft. The aircraft is equipped with a power unit that drives and connects to the propeller. The rotor hub assembly includes:

[0005] Mounting base, driving connection to the output end of the power device;

[0006] The rotor hub has two mounting positions at its end for mounting the rotor blades, and the two mounting positions are distributed along a first direction.

[0007] A flapping hinge, through which the propeller hub is mounted on the mounting base;

[0008] A reference straight line is obtained by rotating the first direction along the rotation direction of the propeller hub by an included angle θ. The axis of the flapping hinge is parallel to the reference straight line, and the included angle θ ranges from 10° to 80°.

[0009] In one embodiment, the two blades are assembled together via the hub and share the flapping hinge.

[0010] In one embodiment, the included angle θ ranges from 30° to 45°.

[0011] In one embodiment, the propeller hub is provided with a pre-cone angle to cause the propeller blades to tilt upwards, and the value of the pre-cone angle ranges from 1° to 8°.

[0012] In one embodiment, the pre-cone angle ranges from 3° to 5°.

[0013] In one embodiment, the suspension point of the propeller hub is set at the same height as the line connecting the centers of gravity of the two propeller blades.

[0014] In one embodiment, the propeller hub assembly further includes a damping structure comprising two damping portions disposed on both sides of the axis of the flapping hinge, the damping portions connecting the propeller hub and the mounting base.

[0015] In one embodiment, the propeller hub is provided with a clearance hole, the mounting base is provided with a rotating shaft portion passing through the clearance hole, the clearance hole is provided with two clearance wall surfaces opposite each other in a direction perpendicular to the axis of the flapping hinge, and the damping portion is at least partially provided at the interval between the clearance wall surfaces and the peripheral side surface of the rotating shaft portion.

[0016] In one embodiment, the clearance hole is provided with two guide walls that are axially opposite to the swing hinge, and the pivot portion is provided with two guide surfaces corresponding to the guide walls, the guide surfaces abutting against the guide walls.

[0017] In one embodiment, the propeller hub is further provided with a first through hole communicating with the clearance hole, the rotating shaft is provided with a second through hole corresponding to the first through hole, and the flapping hinge is installed through the first through hole and the second through hole.

[0018] In one embodiment, the swinging hinge includes a swinging bolt, a swinging nut, and a bushing, the bushing being disposed within the first through hole, and one end of the swinging bolt passing through the bushing and connected to the swinging nut.

[0019] In one embodiment, the swinging hinge further includes a bearing disposed within the second through hole, and the swinging bolt passes through the bearing.

[0020] In one embodiment, the propeller hub includes a first hub housing and a second hub housing connected to each other, and the mounting position is configured to form a hole structure between the first hub housing and the second hub housing.

[0021] In one embodiment, the mounting base includes a pivot portion and a mounting portion. The pivot portion is connected to the flapping hinge, and the mounting portion is connected to the lower end of the pivot portion and is used to connect to the output end of the power device. The propeller hub assembly also includes two elastic members. The two ends of the elastic members are respectively connected to the propeller hub and the mounting portion, and the two elastic members are spaced apart along the first direction.

[0022] In one embodiment, the elastic element is configured as a tension spring, one end of which is hooked onto the upper end face of the mounting portion, and the other end is hooked onto the lower end face of the propeller hub.

[0023] In one embodiment, a limiting boss is provided on the peripheral side of the rotating shaft. The limiting boss is located below the propeller hub. A limiting surface is provided on the limiting boss. The lower end surface of the propeller hub can abut against the limiting surface to limit the swing limit position of the propeller hub.

[0024] This utility model also proposes a propeller, including two blades and the aforementioned hub assembly, wherein the two blades are respectively disposed at two mounting positions at the ends of the hub.

[0025] This utility model also proposes an aircraft, including a fuselage, a power unit and the aforementioned propeller, wherein the power unit is located in the fuselage and drives the propeller.

[0026] In one embodiment, the aircraft is configured as a vertical takeoff and landing (VTOL) aircraft.

[0027] The technical solution of this utility model, by setting a flapping adjustment coefficient, can achieve blade pitch angle adjustment without the need for a pitch hinge, and uses adaptive adjustment of the pitch angle to suppress and reduce blade flapping amplitude. On the one hand, the propeller can be positioned as close as possible to the aircraft fuselage during the design phase, thereby reducing the cruise drag caused by the propeller; on the other hand, it can reduce periodic oscillations caused by blade flapping, improve hub life, and enhance flight stability and safety. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a propeller embodiment provided by this utility model;

[0030] Figure 2 for Figure 1 Top view of the embodiment shown;

[0031] Figure 3 for Figure 1 The front view of the embodiment shown;

[0032] Figure 4 for Figure 1 The illustrated embodiment is viewed from the axial perspective of the swing hinge;

[0033] Figure 5 for Figure 4 Sectional view at point AA.

[0034] Explanation of icon numbers:

[0035] 100. Hub assembly; 110. Hub; 111. First hub housing; 112. Second hub housing; 113. Clearance hole; 114. First through hole; 115. Clearance wall; 116. Guide wall; 117. Mounting position; 120. Swinging hinge; 121. Swinging bolt; 122. Swinging nut; 123. Bushing; 124. Bearing; 130. Mounting seat; 131. Shaft; 132. Mounting part; 133. Guide surface; 134. Second through hole; 135. Limiting boss; 136. Limiting surface; 140. Damping structure; 141. Damping part; 150. Elastic element; 200. Blade.

[0036] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0038] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0040] This invention proposes a propeller hub assembly for use in the propeller of an aircraft. The aircraft is equipped with a power device that drives and connects to the propeller, and the propeller can rotate under the output torque of the power device.

[0041] Please see Figures 1 to 5 In one embodiment of the present invention, the propeller hub assembly 100 includes a mounting base 130, a propeller hub 110 and a flapping hinge 120. The mounting base 130 is driven to connect to the output end of the power device. Propeller blades 200 are mounted on both ends of the propeller hub 110. The propeller hub 110 is mounted on the mounting base 130 through the flapping hinge 120.

[0042] Optionally, the two blades 200 are assembled as a single unit via a hub 110 and share a flapping hinge 120. That is, in this embodiment, the two blades 200 are assembled as a single unit via a hub 110 and can perform a unified flapping motion relative to a common flapping hinge 120, resulting in a seesaw configuration (i.e., a semi-rigid configuration) for the propeller. On the one hand, compared to a fully hinged hub 110, the seesaw-type hub 110 of this invention simplifies the construction of the hub assembly 100 by eliminating the flapping hinge and damper, thus reducing the structural complexity of the propeller and lowering its manufacturing and maintenance costs. On the other hand, compared with the all-rigid propeller hub 110, the seesaw-type propeller hub 110 of this utility model has a degree of freedom of swing through the swing hinge 120 to unload aerodynamic forces. Therefore, the rigidity requirement of the blade 200 is lower. Ordinary blades 200 can be directly applied to the propeller hub assembly 100 without special modification, thus making the propeller hub assembly 100 highly versatile.

[0043] It should be noted that the rotor hub assembly 100 of this utility model is not limited to any particular aircraft type; it can be an eVTOL (Electric Vertical Takeoff and Landing) aircraft, a helicopter, etc. The configuration of an eVTOL includes, but is not limited to, multi-rotor configurations, compound wing configurations, and tiltrotor configurations. Taking a compound wing eVTOL as an example, the aircraft includes a fixed wing and multiple rotors, including a lift rotor. The rotor hub assembly 100 of this utility model can be applied to this lift rotor.

[0044] Please see Figure 2 Optionally, the end of the hub 110 is provided with two mounting positions 117 for mounting the blades 200. The two mounting positions 117 are distributed along a first direction. A reference straight line is obtained by rotating the first direction along the rotation direction of the hub 110 by an included angle θ. The axis of the flapping hinge 120 is parallel to the reference straight line. The included angle θ ranges from 10° to 80°.

[0045] For easier understanding, please refer to Figure 2 The axis MN of the flapping hinge 120 can be considered as being composed of a first ray OM and a second ray ON, respectively located on both sides of the rotation axis at the output end of the power unit. Simultaneously, the first direction PQ can be considered as being composed of a third ray OP and a fourth ray OQ, respectively located on both sides of the rotation axis at the output end of the power unit. The first ray OM is close to the third ray OP and one of its mounting positions 117, while the second ray ON is close to the fourth ray OQ and the other mounting position 117. The angle between the first ray OM and the third ray OP is θ, and the first ray OM is located in front of the third ray OP in the rotation direction of the rotor hub 110. Similarly, the angle between the second ray ON and the fourth ray OQ is also θ, and the second ray ON is located in front of the fourth ray OQ in the rotation direction of the rotor hub 110. That is, when the rotor hub 110 rotates, the first ray OM will pass through the same reference point in both of their directions of travel before the third ray OP, and the second ray ON will pass through the same reference point in both of their directions of travel before the fourth ray OQ.

[0046] That is, when the axis of the flapping hinge 120 and the first direction are projected onto the rotation plane of the hub 110, these two projected lines intersect at an acute angle. This is equivalent to deflecting the flapping hinge 120 by an acute angle based on the conventional flapping hinge 120 in the prior art. Thus, by designing the flapping hinge 120 to be non-perpendicular to the first direction, the propeller can change the pitch angle of the blade 200 while performing flapping motion. Furthermore, since the end of the flapping hinge 120 is located in front of its adjacent mounting position 117, the preceding blade 200 (reference...) Figure 2 The leftmost blade (200) is propelled upwards by a greater aerodynamic force, while the trailing blade (200) (reference) Figure 2 When the rightmost blade (200) flaps downwards due to a smaller aerodynamic force, the upward flapping motion of the advancing blade (200) reduces both its pitch angle and angle of attack. This decrease in angle of attack reduces the aerodynamic force on the advancing blade (200), thus suppressing its upward flapping motion and reducing its amplitude. Similarly, the downward flapping motion of the retreating blade (200) increases both its pitch angle and angle of attack. This increase in angle of attack increases the aerodynamic force on the retreating blade (200), suppressing its downward flapping motion and reducing its amplitude.

[0047] In this embodiment, the included angle θ is defined as the swing adjustment coefficient. The included angle θ is directly proportional to the swing adjustment coefficient; that is, the larger the included angle θ, the larger the swing adjustment coefficient, and vice versa. It can be understood that the larger the included angle θ, the greater the change in pitch angle caused by the swinging motion; the smaller the included angle, the smaller the change in pitch angle caused by the swinging motion. Therefore, in order for the swing hinge 120 to simultaneously achieve two degrees of freedom of movement—swinging and pitch change—and to maintain a good balance between the two, the swing adjustment coefficient, i.e., the included angle θ, cannot be set too large or too small. Preferably, the included angle θ ranges from 30° to 45°, for example, values ​​of 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44° or 45°. In this way, the change in the pitch angle caused by the blade flapping action is sufficient to curb further blade flapping without causing significant changes in the aerodynamic forces acting on the blades that would affect flight control.

[0048] In this way, the pitch angle of the blade 200 can be adjusted without setting a pitch hinge, and the flapping amplitude of the blade 200 can be suppressed and reduced by means of adaptive adjustment of the pitch angle. On the one hand, the propeller can be set as close as possible to the aircraft fuselage during the design stage, thereby reducing the cruise drag caused by the propeller; on the other hand, it can reduce the periodic oscillation caused by the flapping of the blade 200, improve the life of the hub 110, and enhance flight stability and safety.

[0049] In this embodiment, by retaining the flapping hinge 120 and saving the oscillating hinge and pitch hinge, the structural complexity and weight of the propeller can be significantly reduced, as well as the manufacturing cost and subsequent maintenance cost of the propeller. On this basis, the root bending moment unloading function caused by uneven aerodynamic loads of the eVTOL propeller can be met.

[0050] Optionally in this embodiment, the rotor hub 110 is provided with a pre-cone angle to cause the rotor blades 200 to tilt upwards. The value of the pre-cone angle ranges from 1° to 8°. It should be noted that the pre-cone angle refers to the angle between the line connecting the midpoint of the end face of the rotor hub 110 and the center point of the entire structure, and the horizontal plane when the hub is stationary. Figure 3The included angle β is shown. Since the chord line of blade 200 is approximately parallel to the line connecting the midpoint of the end face of the hub and the overall center point, when the hub 110 has the aforementioned pre-cone angle, the blade 200 will extend upwards in the direction from the blade root to the blade tip. After the hub 110 rotates once, the chord line of blade 200 can form a cone with the cone angle pointing downwards. This increases the bending moment of centrifugal force on the blade root, and uses this bending moment to balance the bending moment of lift force on the blade 200, thereby achieving the unloading effect of centrifugal force on the blade 200 relative to the aerodynamic force on the blade 200. In other words, it unloads the blade 200 within the flapping surface, thus reducing the risk of premature failure of the blade 200 due to material fatigue. Of course, in other embodiments, the pre-cone angle can also be other ranges, such as zero degrees or -10° to -1°. When the pre-cone angle is negative, it means that the line connecting the midpoint of the end face of the rotor hub and the center point of the whole extends downward in the direction from the rotor root to the rotor tip.

[0051] It is understood that the pre-cone angle in this embodiment should not be too large or too small. An excessively large pre-cone angle will cause the bending moment of the centrifugal force on the blade root to be too large, resulting in the centrifugal force bending moment significantly exceeding the lift bending moment, which is clearly counterproductive. An excessively small pre-cone angle will result in insufficient bending moment of the centrifugal force on the blade root, leading to insufficient unloading effect of the centrifugal force. Preferably, the pre-cone angle is in the range of 3° to 5°, for example, 3°, 4°, or 5°. This allows for a better balance between the bending moment of the centrifugal force on the blade root and the bending moment of the lift on the blade root, thereby achieving effective unloading of the blade 200 within the flapping surface without generating additional load. Of course, other values ​​can be used in other embodiments, such as 6° or 7°.

[0052] Optionally in this embodiment, the suspension point of the rotor hub 110 is set at the same height as the line connecting the centers of gravity of the two rotor blades 200. That is, when the rotor hub 110 is in a horizontal position, i.e., when the first direction extends horizontally, the suspension point of the rotor hub 110 and the center of gravity of the rotor blades 200 are on the same horizontal plane. In this embodiment, since the suspension point is located on the axis of the flapping hinge 120, the line connecting the centers of gravity of the two rotor blades 200 passes through the flapping hinge 120. It should be noted that there is a height difference between the intersection point of the suspension point and the chord line of the two rotor blades 200, and this height difference is the suspension height. It can be understood that in this embodiment, the value of the suspension height can be adjusted according to different design needs, as long as the suspension point and the center of gravity of the rotor blades 200 are at the same height. Thus, by setting the pre-cone angle and connecting the center of gravity of the two blades 200 through the flapping hinge 120, the first-order harmonic Coriolis force caused by the pre-cone angle can be eliminated, reducing the excessive alternating load transmitted to the aircraft body, thereby improving the frequency and amplitude of vibration.

[0053] Please see Figure 2Optionally, in this embodiment, the rotor hub assembly 100 further includes a damping structure 140, which includes two damping parts 141. The two damping parts 141 are respectively disposed on both sides of the axis of the flapping hinge 120, and the damping parts 141 connect the rotor hub 110 and the mounting base 130. Specifically, the distribution direction of the two damping parts 141 is in the same direction as the flapping motion, so that the damping parts 141 can provide a damping effect during the flapping of the rotor blade 200, thereby reducing the flapping amplitude and improving vibration and noise problems.

[0054] Optionally, the distribution direction of the two damping portions 141 is perpendicular to the axis of the flapping hinge 120. In this way, under the condition of equal flapping amplitude, the elastic deformation of the two damping portions 141 can reach its maximum, thereby maximizing the damping force of the damping structure 140 acting on the rotor hub 110. Of course, in other embodiments, the distribution direction of the two damping portions 141 may intersect but not be perpendicular to the axis of the flapping hinge 120.

[0055] Optionally, the damping portion 141 is configured as a damping block, and the damping structure 140 includes two separate damping blocks, which are spaced apart on both sides of the axis of the flapping hinge 120. The material of the damping blocks is not specifically limited, and includes, but is not limited to, rubber or silicone. The damping properties of rubber help absorb high-frequency vibrations. Thus, individual damping blocks are easier to manufacture and mold, and easier to assemble onto the rotor hub 110. Of course, in other embodiments, the damping structure 140 can also be a ring-shaped damping ring block, with the two opposite sidewalls of the damping ring block forming the two damping portions 141.

[0056] Please refer to the following: Figure 5 In this embodiment, optionally, the rotor hub 110 is provided with a clearance hole 113, and the mounting base 130 is provided with a rotating shaft portion 131 passing through the clearance hole 113. The clearance hole 113 is provided with two clearance wall surfaces 115 facing each other in a direction perpendicular to the axis of the swing hinge 120. The damping portion 141 is at least partially provided at the interval between the clearance wall surface 115 and the peripheral side surface of the rotating shaft portion 131. Thus, during the swinging of the rotor blade 200, the interval between the peripheral side surface of the rotating shaft portion 131 and the clearance wall surface 115 will change, thereby causing the damping portion 141 to be deformed under pressure, so as to achieve a damping effect on the swinging motion. Of course, in other embodiments, the upper end face of the rotor hub 110 may be provided with a damping platform, and the portion of the rotating shaft portion 131 extending out of the upper end face of the rotor hub 110 may be spaced apart from the damping platform, with the damping portion 141 provided at the interval.

[0057] Please see Figures 2 to 5Optionally, in this embodiment, the clearance hole 113 is provided with two guide walls 116 that are axially opposite to each other on the flapping hinge 120, and the rotating shaft portion 131 is provided with two guide surfaces 133 corresponding to the guide walls 116, with the guide surfaces 133 abutting against the guide walls 116. Thus, the guide surfaces 133 and 116 cooperate with each other to guide the blade 200 during flapping, making the flapping motion smoother and more stable. Of course, in other embodiments, the guide walls 116 and 133 may not be provided.

[0058] Please see Figure 2 Optionally, in this embodiment, the cross-sectional shape of both the rotating shaft portion 131 and the clearance hole 113 is approximately oval, with the oval length of the clearance hole 113 being greater than the oval length of the rotating shaft portion 131, and the oval width of the clearance hole 113 being equal to the oval width of the rotating shaft portion 131. Of course, in other embodiments, the cross-sectional shape of the rotating shaft portion 131 and the clearance hole 113 can also be other shapes, such as rectangles or hexagons.

[0059] Please see Figure 5 Optionally, in this embodiment, the propeller hub 110 is further provided with a first through hole 114 connecting the clearance hole 113, and the rotating shaft part 131 is provided with a second through hole 134 corresponding to the first through hole 114. The flapping hinge 120 is installed through the first through hole 114 and the second through hole 134. Thus, the structure is simple and easy to implement.

[0060] Please see Figure 5 Optionally in this embodiment, the swing hinge 120 includes a swing bolt 121, a swing nut, and a bushing 123. The bushing 123 is disposed within the first through hole 114, and one end of the swing bolt 121 passes through the bushing 123 and is connected to the swing nut. Thus, by utilizing the good self-lubricating properties of the bushing 123, direct contact between the swing bolt 121 and the first through hole 114 can be avoided, reducing friction and energy loss, improving the structural stability of the swing hinge 120, and extending the service life of the swing hinge 120.

[0061] Optionally, the flapping hinge 120 also includes a bearing 124, which is disposed within the second through hole 134, and the flapping bolt 121 passes through the bearing 124. In this way, rolling friction is used instead of sliding friction by utilizing the bearing 124, reducing friction and mechanical losses. Furthermore, the bearing 124 is responsible for bearing the variable operating load caused by sudden changes in the speed of the blade 200, providing good maintainability. Of course, in other embodiments, only one of the bushing 123 and the bearing 124 may be provided, or neither may be provided.

[0062] Please see Figure 5Optionally, in this embodiment, two bearings 124 are provided, with the two bearings 124 respectively located at opposite ends of the second through hole 134. This paired arrangement of bearings 124 helps maintain the stability and coaxiality of the swing bolt 121, thereby reducing vibration and oscillation, and improving the mechanical efficiency of the swing hinge 120. It is worth mentioning that the swing hinge 120 shared by the two blades 200 does not bear centrifugal force but only transmits tension and rotor torque, which reduces the load on the bearing 124, thereby extending the service life of the bearing 124.

[0063] Please see Figure 1 and Figure 5 Optionally in this embodiment, the propeller hub 110 includes a first hub shell 111 and a second hub shell 112 connected together, and the mounting position 117 is configured as a hole structure formed between the first hub shell 111 and the second hub shell 112. Specifically, the opening of the mounting position 117 is located on the end face of the propeller hub 110, the first hub shell 111 and the second hub shell 112 are connected by fasteners such as bolts, and the propeller blade 200 is sandwiched between the first hub shell 111 and the second hub shell 112. Thus, the structure is simple and easy to implement. Of course, in other embodiments, the mounting position 117 can also be a plate-like structure or the like located at the end of the propeller hub 110.

[0064] Optionally in this embodiment, the first hub housing 111 and the second hub housing 112 are provided with mounting grooves (not shown in the drawings), and the damping block is disposed in the mounting grooves of the first hub housing 111 and the second hub housing 112. Specifically, the damping block can be placed directly in the mounting groove, or it can be glued to the mounting groove with an adhesive.

[0065] Please see Figures 3 to 5 Optionally, in this embodiment, the mounting base 130 includes a rotating shaft portion 131 and a mounting portion 132. The rotating shaft portion 131 is connected to the flapping hinge 120, and the mounting portion 132 is connected to the lower end of the rotating shaft portion 131 and is used to connect to the output end of the power device. The propeller hub assembly 100 also includes two elastic members 150. The two ends of the elastic members 150 are respectively connected to the propeller hub 110 and the mounting portion 132. The two elastic members 150 are spaced apart along a first direction and are respectively disposed on both sides of the axis of the flapping hinge 120. In this way, by utilizing the damping effect of the elastic members 150 in the flapping motion of the propeller blade 200, the flapping amplitude can be reduced, and the vibration and noise reduction effects can be achieved. At the same time, the vibration and operability of the propeller can also be improved. It can be understood that in the embodiment where the propeller hub assembly 100 is provided with a damping portion 141, the elastic members 150 can also play the role of adjusting the flapping damping of the propeller system. Of course, in other embodiments, the elastic members 150 may not be provided.

[0066] It is worth mentioning that in embodiments where the hub assembly 100 is applied to a lift rotor with a compound airfoil configuration or a tiltrotor configuration, since the lift rotor does not rotate in the aircraft's cruise mode, the propeller is in a feathered state. However, the blade 200 is easily affected by airflow and may pitch up or tilt. Furthermore, when the blade 200 pitches in a feathered state, it causes the hub 110 to pitch relative to the axis of the flapping hinge 120. In this embodiment, two elastic members 150 are respectively disposed on both sides of the axis of the flapping hinge 120. One elastic member 150 is connected to one end of the hub 110, and the other elastic member 150 is connected to the other end of the hub 110. When the blade 200 pitches in a feathered state, the elastic deformation of the elastic member 150 near the upward-tilting blade 200 is further increased. This allows the elastic force of the elastic member 150 acting on the hub 110 to suppress the tilting tendency of the upward-tilting blade 200. In this way, the two elastic elements 150 pull the propeller blades 200 on the two mounting positions 117 respectively, which can improve the problem of the propeller blades 200 pitching up or tailing up due to airflow. That is, it can limit the propeller's waving amplitude in cruise mode. Correspondingly, the propeller can be set as close as possible to the aircraft fuselage during the design stage, thereby reducing the cruise drag caused by the propeller.

[0067] Please see Figures 3 to 5 Optionally, the elastic element 150 is configured as a tension spring, with one end hooked onto the upper end face of the mounting portion 132 and the other end hooked onto the lower end face of the propeller hub 110. It should be noted that... Figure 1 , Figures 3 to 5 The tension spring in the diagram is in its natural state, which is why its upper end is not connected to the propeller hub 110 in the illustration. In the actual product, the upper end of the tension spring is connected to the propeller hub 110. This results in a simple and easy-to-implement structure. Furthermore, the spring's elastic properties help support the propeller hub 110 and reduce the impact of low-frequency vibrations. Of course, in other embodiments, the elastic element 150 can also be a compression spring, a spring sheet, or a rubber body, etc.

[0068] It is worth mentioning that in embodiments where the rotor hub assembly 100 is equipped with both an elastic element 150 and a damping structure 140, this combination of the elastic element 150 and the damping structure 140 provides shock absorption and buffering throughout the flapping motion, enhancing the linearity of propeller control, filtering out high and low frequency vibrations, reducing noise, and improving reliability. When the aircraft enters cruise mode, the blades 200 generate flapping motion due to the influence of the incoming flow. The elastic element 150 limits the distance between the lower end face of the rotor hub 110 and the mounting portion 132 and provides restoring force. At the same time, since the flapping torque generated during cruise is not very large, the damping portion 141 provides support force to the shaft portion 131 to keep the flapping amplitude of the blades 200 from exceeding the rated value, reducing the additional drag caused by the blades 200, thereby improving flight time.

[0069] Please see Figures 3 to 5 Optionally, in this embodiment, a limiting boss 135 is provided on the peripheral side of the rotating shaft 131. The limiting boss 135 is located below the propeller hub 110. A limiting surface 136 is provided on the limiting boss 135. The lower end surface of the propeller hub 110 can abut against the limiting surface 136 to limit the swing limit position of the propeller hub 110.

[0070] Specifically, when the rotor hub 110 flaps, its lower end face gradually approaches the limiting surface 136. Due to the combined action of the damping part 141 and the elastic element 150, the lower end face of the rotor hub 110 will not contact the limiting surface 136 during uniform flapping. However, when the propeller encounters a gust of wind or other sudden load changes, the rotor hub 110 may experience a certain acceleration, leading to an increased flapping amplitude. In this case, the lower end face of the rotor hub 110 will approach and contact the limiting surface 136, thus achieving mechanical protection and improving flight stability and safety. Secondly, by directly constructing the limiting surface 136 using the structure of the pivot part 131, the structure of the rotor hub assembly 100 can be simplified, reducing the number of components and structural weight, and lowering its manufacturing cost. Of course, in other embodiments, the limiting boss 135 and the limiting surface 136 may not be provided on the rotating shaft 131. For example, a wave limiter composed of a wave limiting bolt and an elastic filling material may be provided on the mounting base 130, and the elastic material of the wave limiter may be used for buffering, shock absorption and limiting.

[0071] This utility model also proposes a propeller, which includes two blades and the aforementioned hub assembly. The specific structure of the hub assembly is as described in the above embodiments. Since this propeller adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here. Specifically, the two blades are respectively disposed at both ends of the hub. The hub end has two mounting positions, and the two mounting positions and the two blades are distributed along a first direction, with the blades connected to the mounting positions.

[0072] This utility model also proposes an aircraft, such as an electric vertical takeoff and landing (EVTOL) aircraft, which includes a fuselage, a power unit, and the aforementioned propeller. The specific structure of the propeller is as described in the above embodiments. Since this aircraft adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here. The power unit is located on the fuselage and drives the propeller. Specifically, the output end of the power unit extends out of the fuselage and is connected to the mounting base of the propeller hub.

[0073] Optionally, the aircraft includes a fixed wing and multiple rotors, the multiple rotors including lifting rotors, and the lifting rotors including a power unit and the aforementioned propeller. The power unit may be an electric motor or an engine, etc.

[0074] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A propeller hub assembly, characterized in that, include: Mounting base, driven by the output end of the aircraft's power unit; The rotor hub has two mounting positions at its end for mounting rotor blades, and the two mounting positions are distributed along a first direction. A flapping hinge, through which the propeller hub is mounted on the mounting base; A reference straight line is obtained by rotating the first direction along the rotation direction of the propeller hub by an included angle θ. The axis of the flapping hinge is parallel to the reference straight line, and the included angle θ ranges from 10° to 80°.

2. The propeller hub assembly as claimed in claim 1, characterized in that, The two blades are assembled together via the hub and share the flapping hinge.

3. The propeller hub assembly as described in claim 1, characterized in that, The included angle θ ranges from 30° to 45°.

4. The propeller hub assembly as claimed in claim 1, characterized in that, The propeller hub is provided with a pre-cone angle to make the propeller blades tilt upwards, and the value of the pre-cone angle ranges from 1° to 8°.

5. The propeller hub assembly as described in claim 4, characterized in that, The value of the pre-cone angle ranges from 3° to 5°; And / or, the suspension point of the propeller hub is set at the same height as the line connecting the centers of gravity of the two propeller blades.

6. The propeller hub assembly as claimed in claim 1, characterized in that, The propeller hub assembly also includes a damping structure, which includes two damping parts disposed on both sides of the axis of the flapping hinge, and the damping parts connect the propeller hub and the mounting base.

7. The propeller hub assembly as claimed in claim 6, characterized in that, The propeller hub is provided with a clearance hole, the mounting base is provided with a rotating shaft portion passing through the clearance hole, the clearance hole is provided with two clearance walls opposite each other in a direction perpendicular to the axis of the flapping hinge, and the damping portion is at least partially provided at the interval between the clearance wall surface and the peripheral surface of the rotating shaft portion.

8. The propeller hub assembly as claimed in claim 7, characterized in that, The clearance hole is provided with two guide walls that are opposite each other in the axial direction of the swing hinge, and the rotating shaft is provided with two guide surfaces corresponding to the guide walls, the guide surfaces abutting against the guide walls.

9. The propeller hub assembly as claimed in claim 7, characterized in that, The propeller hub is also provided with a first through hole that connects to the clearance hole, and the rotating shaft is provided with a second through hole corresponding to the first through hole. The flapping hinge is installed through the first through hole and the second through hole.

10. The propeller hub assembly as claimed in claim 9, characterized in that, The swinging hinge includes a swinging bolt, a swinging nut, and a bushing. The bushing is disposed in the first through hole, and one end of the swinging bolt passes through the bushing and is connected to the swinging nut.

11. The propeller hub assembly as claimed in claim 10, characterized in that, The swinging hinge also includes a bearing, which is disposed in the second through hole, and the swinging bolt passes through the bearing.

12. The propeller hub assembly as claimed in any one of claims 1 to 11, characterized in that, The propeller hub includes a first hub shell and a second hub shell connected to each other, and the mounting position is configured as a hole structure formed between the first hub shell and the second hub shell.

13. The propeller hub assembly as claimed in any one of claims 1 to 11, characterized in that, The mounting base includes a pivot portion and a mounting portion. The pivot portion is connected to the flapping hinge, and the mounting portion is connected to the lower end of the pivot portion and is used to connect to the output end of the power device. The propeller hub assembly also includes two elastic members. The two ends of the elastic members are respectively connected to the propeller hub and the mounting portion. The two elastic members are spaced apart along the first direction and are respectively disposed on both sides of the axis of the flapping hinge.

14. The propeller hub assembly as claimed in claim 13, characterized in that, The elastic element is configured as a tension spring, one end of which is hooked onto the upper end face of the mounting part, and the other end is hooked onto the lower end face of the propeller hub. And / or, the peripheral side of the rotating shaft is provided with a limiting boss, the limiting boss is located below the propeller hub, the limiting boss is provided with a limiting surface, and the lower end surface of the propeller hub can abut against the limiting surface to limit the swing limit position of the propeller hub.

15. A propeller, characterized in that, It includes two blades and a hub assembly as described in any one of claims 1 to 14, wherein the two blades are respectively disposed at two mounting positions at the ends of the hub.

16. An aircraft, characterized in that, It includes a body, a power unit, and a propeller as described in claim 15, wherein the power unit is disposed in the body and drives a mounting base connected to the propeller.

17. The aircraft as claimed in claim 16, characterized in that, The aircraft is configured as an electric vertical takeoff and landing (EVTOL) aircraft.

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