A constrained seesaw rotor

Abstract

This utility model discloses a constrained seesaw rotor, including a rotor hub for connecting blades. The rotor hub includes a blade mounting seat fixedly connected to the blades, a rotor hub base rotatably connected to one side of the blade mounting seat, a rotating shaft connecting assembly disposed between the blade mounting seat and the rotor hub base, and an elastic limiting member disposed between the rotor hub base and the blade mounting seat. The blade mounting seat rotates about the rotating shaft connecting assembly as the rotation center, and the elastic limiting member is disposed on both sides of the rotation direction of the blade mounting seat.

Description

Technical Field

[0001] This application relates to the field of flight equipment technology, and more specifically, to a constrained seesaw rotor. Background Technology

[0002] Compound aircraft are a new type of aircraft that combines the technological features of fixed-wing and rotary-wing aircraft, aiming to balance vertical takeoff and landing capabilities with efficient forward flight performance. These aircraft are typically equipped with fixed wings, multiple rotor systems for vertical takeoff and landing, and thrust propellers or jet propulsion devices for forward propulsion.

[0003] In a typical mission profile, the compound aircraft relies on its rotor for primary lift during takeoff and landing, enabling vertical or short takeoff and landing, similar to a helicopter. During cruise, the rotor stops rotating or enters a low-power / feeder mode, with lift primarily provided by the fixed wings, while forward thrust is provided by a thrust propeller or jet engine, achieving a high-speed, high-efficiency fixed-wing flight mode. This design significantly improves flight speed and range, overcoming the limitations of traditional helicopters, which are characterized by low speed and short range.

[0004] However, the transition from vertical takeoff and landing (VTOL) mode to forward cruise mode is the most complex and challenging phase in the operation of a compound aircraft. During this phase, the aircraft is in a low-to-medium speed forward flight state, while the rotor system remains rotating to provide some lift and attitude control. At this time, the rotor's aerodynamic environment is extremely complex, particularly manifested in the asymmetric aerodynamic load phenomenon caused by the asymmetric velocity of the rotor's advancing and retreating sides. This asymmetric load is transmitted through the rotor shaft to the fuselage and wings, inducing forced vibrations throughout the aircraft structure, affecting flight stability and crew comfort, and even causing malfunctions in avionics and sensors. Furthermore, alternating stress subjects critical load-bearing components to high-cycle or low-cycle fatigue states, significantly accelerating crack initiation and propagation, shortening structural lifespan, increasing maintenance costs and accident risks, and further complicating flight control.

[0005] Therefore, those skilled in the art need to improve the existing rotor structure to solve the aforementioned technical problems. Utility Model Content

[0006] The main objective of this application is to provide a constrained seesaw rotor that can reduce the asymmetric bending moment of a compound aircraft during the transition phase, thereby improving the structural safety of the rotor.

[0007] To achieve the above objectives, in a first aspect, this application provides a constrained seesaw rotor, including a rotor hub for connecting blades. The rotor hub includes a blade mounting seat fixedly connected to the blades, a rotor hub base rotatably connected to one side of the blade mounting seat, a rotating shaft connecting assembly disposed between the blade mounting seat and the rotor hub base, and an elastic limiting member disposed between the rotor hub base and the blade mounting seat. The blade mounting seat rotates about the rotating shaft connecting assembly as a rotation center, and the elastic limiting member is disposed on both sides of the rotation direction of the blade mounting seat.

[0008] Optionally, the elastic limiting member can be either rubber or a spring.

[0009] Optionally, the propeller hub further includes a flapping limit block disposed on the propeller mounting seat, and the flapping limit block is disposed on both sides of the propeller mounting seat in the rotation direction.

[0010] Optionally, the propeller hub further includes a flapping limit block disposed on the propeller mounting seat, and the flapping limit block is disposed on both sides of the propeller mounting seat in the rotation direction.

[0011] Optionally, the blade and the blade mounting base are integrally formed, or the blade and the blade mounting base are fixedly connected by blade bolts.

[0012] Optionally, the elastic limiting member is inclinedly disposed between the hub base and the blade mounting seat.

[0013] Optionally, the pivot connection assembly includes a flapping shaft disposed between the blade mounting base and the blade hub base, a needle roller bearing housing fixedly connected to the blade hub base, a needle roller bearing and a thrust bearing housed in the needle roller bearing housing, a bearing retainer ring disposed between the thrust bearing and the needle roller bearing, and a flapping shaft bolt screwed onto the flapping shaft.

[0014] Optionally, the inner diameter of the needle roller bearing, the thrust bearing, and the thrust bearing are all equal to the outer diameter of the swing shaft.

[0015] Optionally, the constrained seesaw rotor also includes a rotor shaft fixedly connected to the rotor hub.

[0016] The present invention provides a constrained seesaw rotor, which has the following advantages compared with the prior art: First, the rotating shaft connection assembly rotatably connects the blade mounting seat and the rotor hub base together. The blade mounting seat rotates relative to the rotating shaft connection assembly, so that a degree of freedom of flapping motion is formed between the blade mounting seat and the rotor hub base. This degree of freedom immediately releases the asymmetric bending moment of the blade mounting seat caused by aerodynamics, reduces the bending moment load transmitted from the rotor hub and blades to the rotor shaft, and is beneficial to reducing vibration and improving fatigue life of the aircraft. Secondly, by setting the elastic limiting member between the rotor hub base and the rotor blade mounting base, one end of the elastic limiting member is connected to one side of the rotor blade mounting base, and the other end of the elastic limiting member is connected to the rotor hub base. Under the action of the elastic force of the elastic limiting member, the angle between the rotor blade mounting base and the rotor hub base during the flapping motion is limited, which can reduce the flapping angle of the rotor. Finally, the flapping limit blocks are provided on both sides of the blade mounting base in the direction of rotation. When the flapping angle of the rotor hub base is too large, the flapping limit blocks abut against the blade mounting base. By using the flapping limit blocks, the angle of the blade mounting base during the flapping motion is limited so as not to increase further. This prevents the blade mounting base and the blade from being within the controlled range, further ensuring that the rotor flapping delivery is within the controlled range and ensuring that the rotor does not interfere with other structures of the fuselage. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 Yes: A schematic diagram of this composite aircraft; Figure 2 Yes: A schematic diagram of the lateral structure of the rotor in this composite aircraft; Figure 3 Yes: A schematic diagram of the longitudinal structure of the rotor in this composite aircraft; Figure 4 Yes: A schematic diagram of the propeller hub structure in this utility model; Figure 5 Yes: Schematic diagram of the exploded structure of the propeller hub; Figure 6 Yes: A cross-sectional structural diagram of the propeller hub.

[0018] The components are: 1 rotor; 2 rotor hub; 3 rotor blade; 4 rotor shaft; 21 rotor blade mounting base; 22 rotor hub base; 23 shaft connection assembly; 24 elastic limiter; 25 flapping limiter block; 26 rotor blade bolt; 211 flapping shaft; 231 needle roller bearing housing; 232 needle roller bearing; 233 thrust bearing; 234 bearing retaining ring; 235 flapping shaft bolt. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] In addition, the term "multiple" should mean two or more.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figures 1-6 As shown, a constrained seesaw rotor 1 includes a rotor hub 2 for connecting blades 3, and a rotor shaft 4 fixedly connected to the rotor hub 2.

[0026] The propeller hub 2 includes a propeller mounting base 21 fixedly connected to the propeller blade 3, a propeller hub base 22 rotatably connected to one side of the propeller mounting base 21, a rotating shaft connecting assembly 23 disposed between the propeller mounting base 21 and the propeller hub base 22, an elastic limiting member 24 disposed on the propeller hub base 22 and between the propeller mounting base 21, and a waving limiting block 25 disposed on the propeller mounting base 21.

[0027] The blade mounting base 21 is provided with a blade mounting groove and a shaft mounting hole to realize the connection between the blade mounting base 21, the blade 3, and the hub base 22. The blade mounting groove and the shaft mounting hole are existing technologies and will not be described in detail here.

[0028] The rotor hub base 22 is used to install the blade mounting seat 21, and the rotor hub base 22 is provided with a rotor shaft 4. The rotor shaft 4 is installed on the aircraft with other structures such as motors or transmission structures. In this embodiment, the rotor hub base 22 is provided with a rotating shaft mounting hole, and the rotating shaft connecting assembly 23 can pass through the rotating shaft mounting hole to realize the rotational connection between the rotor hub base 22 and the blade mounting seat 21.

[0029] The rotating shaft connection assembly 23 includes a flapping shaft 211 disposed between the blade mounting seat 21 and the hub base 22, a needle roller bearing seat 231 fixedly connected to the hub base 22, a needle roller bearing 232 and a thrust bearing 233 housed in the needle roller bearing seat 231, a bearing retaining ring 234 disposed between the thrust bearing 233 and the needle roller bearing 232, and a flapping shaft bolt 234 screwed onto the flapping shaft 21. The waving shaft 211 is fixedly connected to the blade mounting base 21, and the free end of the waving shaft 211 is inserted into the needle roller bearing housing 231. The needle roller bearing 232 and the thrust bearing 233 are both sleeved on the waving shaft 211 to facilitate the rotation of the waving shaft 211 and the blade mounting base 21. The bearing retaining ring 234 is disposed between the needle roller bearing 232 and the thrust bearing 233 to prevent the needle roller bearing 232 and the thrust bearing 233 from colliding and interfering with each other. The waving shaft bolt 234 is screwed onto the waving shaft 21, and the free end of the waving shaft bolt 234 closes the opening of the needle roller bearing housing 231, restricting the position of the needle roller bearing 232, the thrust bearing 233, and the bearing retaining ring 234 within the needle roller bearing housing 231. The inner diameters of the needle roller bearing 232, the thrust bearing 233, and the thrust bearing 233 are all equal to the outer diameter of the swing shaft 211, so as to stabilize the positions of the needle roller bearing 232, the thrust bearing 233, and the thrust bearing 233 on the swing shaft 211. Moreover, the connection between the swing shaft 211 and the blade mounting base 21 is either a threaded connection or welding, thereby achieving a fixed connection between the swing shaft 211 and the blade mounting base 21.

[0030] During operation, the rotating shaft connection assembly 23 rotatably connects the blade mounting seat 21 and the rotor hub base 22 together. The blade mounting seat 21 rotates around the rotating shaft connection assembly 23 as the rotation center, which forms a degree of freedom of flapping motion between the blade mounting seat 21 and the rotor hub base 22. This degree of freedom immediately releases the asymmetric bending moment of the blade mounting seat 21 caused by aerodynamics, reducing the bending moment load transmitted from the rotor hub 2 and blade 3 to the rotor shaft, which is beneficial to reducing vibration and improving fatigue life of the aircraft.

[0031] The elastic limiting member 24 can be any one of rubber or spring. The elastic limiting member 24 is disposed between the propeller hub base 22 and the propeller mounting seat 21. In this embodiment, there are two elastic limiting members 24, and the elastic limiting members 24 are disposed on both sides of the rotation direction of the propeller mounting seat 21. One end of the elastic limiting member 24 is connected to one side of the propeller mounting seat 21, and the other end of the elastic limiting member 24 is connected to the propeller hub base 22. Under the action of the elastic force of the elastic limiting member 24, the angle between the propeller mounting seat 21 and the propeller hub base 22 during the swinging movement is limited. The elastic limiting member 24 is inclinedly disposed between the propeller hub base 22 and the propeller mounting seat 21. The fixed connection structure between the elastic limiting member 24, the propeller hub base 22, and the propeller mounting seat 21 is prior art and will not be described in detail here. When the blade mounting base 21 is rotated under force, it is also tilted to facilitate the transmission of force to the elastic limiting member 24. When the rotor hub 2 is not under force, the elastic limiting member 24 does not deform, and the blade mounting base 21 remains horizontal. When the rotor hub 2 is under force, one side of the elastic limiting member 24 is stretched, and the other side is compressed, thereby generating a restoring elastic torque between the rotor hub base 22 and the blade mounting base 21 to prevent the rotor flapping angle from being too large. In addition, in the utility model, the elastic limiting member 24 has two implementations. In the first implementation, one end of the elastic limiting member 24 is connected to the bottom of the blade mounting base 21, and the other end of the elastic limiting member 24 is connected to the blade hub base 22. In the second implementation, one end of the elastic limiting member 24 is connected to the side of the blade hub base 22 near the rotating shaft connecting assembly 23, and the other end of the elastic limiting member 24 is connected to the blade mounting base 21.

[0032] The waving limit block 25 is used to limit the rotation position of the blade mounting base 21. The waving limit block 25 is provided on both sides of the rotation direction of the blade mounting base 21. The height of the waving limit block 25 is less than the height of the elastic limit member 24, and a height difference is formed between the waving limit block 25 and the elastic limit member 24. When the waving angle of the hub base 22 is too large, the waving limit block 25 abuts against the blade mounting base 21. The waving limit block 25 is used to limit the angle of the blade mounting base 21 during the waving motion so that it will not increase further, thereby preventing the blade mounting base 21 and the blade 3 from being within the controlled range.

[0033] The blade 3 is an airfoil mounted on an aircraft rotor or engine shaft, converting power into aerodynamics through high-speed rotation. Its structure includes the blade body, blade root, and blade tip, with its leading edge aligned with the engine's rotation direction, resembling an airfoil. The blade 3 is a prior art technology. The blade 3 is fixedly connected to the blade mounting base 21, wherein the blade 3 and the blade mounting base 21 are integrally formed, or the blade and the blade mounting base 21 are fixedly connected by blade bolts 26, ensuring the stable position of the blade 3 on the blade mounting base 21.

[0034] The rotor shaft 4 is an important rotating shaft connecting the rotor and the fuselage. The rotor shaft 4 can be installed on the aircraft through other structures such as motors or transmission structures. The rotor shaft 4 and the rotor hub base 22 are integrally formed. When the rotor shaft 4 rotates, the rotor shaft 4 synchronously drives the rotor hub 2 and the rotor blades 3 to rotate. The rotor shaft 4 is a prior art and will not be described in detail here.

[0035] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A tethered seesaw rotor characterized by: The device includes a rotor hub for connecting rotor blades. The rotor hub includes a rotor blade mounting base fixedly connected to the rotor blades, a rotor hub base rotatably connected to one side of the rotor blade mounting base, a rotating shaft connecting assembly disposed between the rotor blade mounting base and the rotor hub base, and an elastic limiting member disposed between the rotor hub base and the rotor blade mounting base. The rotor blade mounting base rotates about the rotating shaft connecting assembly as a rotation center, and the elastic limiting member is disposed on both sides of the rotor blade mounting base in the direction of rotation.

2. A tethered seesaw rotor as in claim 1, wherein: The elastic limiting element can be either rubber or a spring.

3. A constrained seesaw rotor as described in claim 1, characterized in that: The propeller hub also includes a flapping limit block disposed on the propeller mounting base, and the flapping limit block is disposed on both sides of the propeller mounting base in the direction of rotation.

4. A tethered seesaw rotor as in claim 3, wherein: The height of the waving limiting block is less than the height of the elastic limiting member.

5. A tethered seesaw rotor as in claim 1, wherein: The blade and the blade mounting base are integrally formed, or the blade and the blade mounting base are fixedly connected by blade bolts.

6. A tethered seesaw rotor as in claim 1, wherein: The elastic limiting member is inclinedly disposed between the propeller hub base and the propeller mounting seat.

7. A tethered seesaw rotor as in claim 1, wherein: The rotating shaft connection assembly includes a flapping shaft disposed between the blade mounting base and the blade hub base, a needle roller bearing housing fixedly connected to the blade hub base, a needle roller bearing and a thrust bearing housed in the needle roller bearing housing, a bearing retainer ring disposed between the thrust bearing and the needle roller bearing, and a flapping shaft bolt screwed onto the flapping shaft.

8. A tethered seesaw rotor as in claim 7, wherein: The inner diameter of the needle roller bearing, the thrust bearing, and the thrust bearing are all equal to the outer diameter of the swing shaft.

9. A constrained seesaw rotor as described in claim 1, characterized in that: The constrained seesaw rotor also includes a rotor shaft fixedly connected to the rotor hub.

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