A variable-pitch shaftless twin-rotor ducted device

Abstract

The present invention discloses a variable-pitch shaftless twin-rotor ducted device, comprising a duct, wherein an upper rotor assembly without a rotor shaft, a moving ring and a fixed ring assembly, and a lower rotor assembly without a rotor shaft are sequentially distributed axially inside the duct; the upper rotor assembly comprises a multi-pole stator mounted inside the duct, connected to a rotor via a fixed bearing, and rotatably connected to blades in the circumferential direction of the rotor; the moving ring and fixed ring assembly comprises a fixed ring mounted inside the duct and capable of sliding axially, connected to the moving ring via a large bearing, and provided with a pull rod interface in the circumference of the fixed ring, which extends through an opening in the outer wall of the duct; the blades are provided with a variable-pitch rocker arm at their tips, which is connected to the moving ring via a variable-pitch pull rod. The present invention enables the upper and lower rotors to reliably achieve variable pitch motion, timely adjusts the collective pitch angle of the blades, enables the blades to operate in an optimal posture, and improves rotor efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of vertical take-off and landing aircraft, and relates to a variable-pitch shaftless twin-rotor ducted device. Background Art

[0002] A ducted rotor is a power device in which a duct surrounds the rotor. Compared with a shafted ducted rotor, the chord length of the blade section of a shaftless ducted rotor near the duct wall is longer. At the same time, since the shaftless ducted rotor has no centerbody structure, it does not interfere with the rotor flow field, and the effective rotor diameter can be longer, thus greatly improving the aerodynamic performance of the rotor.

[0003] The shaftless rim propulsion in the shipbuilding field ([1] Yu Zhimin, Wang Renzhong, Meng Xiangquan. Design of underwater probe based on combined unpowered propulsion and shaftless rim propulsion [J]. Ship Science and Technology, 2017, 39(23): 26-29) and the shaftless ducted rotor of Nanjing University of Aeronautics and Astronautics ([2] Shen Suiyuan, Zhu Qinghua, Zeng Jianan. Numerical study on aerodynamic characteristics of shaftless ducted rotor [J]. Journal of Aerospace Power, 2019, 34(9)) have been studied. The shaftless ducted rotor structure fixes the motor stator in the duct and combines the rotor with the rotor at the blade tip. The rotor and rotor blades rotate through the electromagnetic action of the motor.

[0004] The current shaftless ducted rotor structure has no pitch-changing mechanism, and the aerodynamic environment in which the rotor blades are located is complex during actual use. Especially when the rotor speed needs to change frequently to control the aircraft's attitude, the blades cannot operate at the optimal attitude. Summary of the Invention

[0005] Purpose of the Invention: To provide a variable-pitch shaftless twin-rotor ducted device. This invention enables the upper and lower rotors to reliably achieve variable pitch motion, timely adjusting the collective pitch angle of the blades to ensure the blades operate in the optimal posture, thereby improving rotor efficiency.

[0006] Technical solution: A variable-pitch shaftless twin-rotor duct device, comprising a duct, on the inside of which are distributed axially an upper rotor assembly without a rotor shaft, a moving ring and a fixed ring assembly, and a lower rotor assembly without a rotor shaft; the upper rotor assembly comprises a multi-pole stator mounted on the inside of the duct, the multi-pole stator being connected to the rotor via a fixed bearing, the rotor being circumferentially rotatably connected to a blade; the moving ring and the fixed ring assembly comprising a fixed ring mounted on the inside of the duct and capable of sliding axially, the fixed ring being connected to the moving ring via a large bearing, a pull rod interface being circumferentially provided with the fixed ring, the pull rod interface extending through an opening on the outer wall of the duct; the tip of the blade is provided with a pitch-changing rocker arm, the pitch-changing rocker arm being connected to the moving ring via a pitch-changing pull rod.

[0007] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the tip of the blade is rotatably connected to the rotor.

[0008] In the aforementioned variable-pitch shaftless twin-rotor ducted device, one end of the variable-pitch rocker arm close to the leading edge of the blade is hinged to the variable-pitch pull rod.

[0009] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the blades are rotatably connected to the rotor via an axial hinge; the axial hinge is composed of a shaft neck, a radial bearing and a thrust bearing, and the shaft neck and the blades are fixedly connected by blade bolts; two radial bearings are installed at the rear end of the shaft neck to realize the variable pitch movement of the blades relative to the rotor while transmitting the lift and bending moment of the blades; at the same time, a thrust bearing is also installed at the rear end of the shaft neck to transmit the centrifugal force of the blades to the rotor.

[0010] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the upper and lower rotor assemblies have the same structure; the rotation axes of the blades of the upper and lower rotor assemblies coincide, and the rotation directions are opposite, and the counter-torques generated by each cancel each other out.

[0011] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the duct lip shape is designed according to aerodynamic requirements.

[0012] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the upper rotor assembly has three blades.

[0013] In the aforementioned variable-pitch shaftless twin-rotor ducted device, the moving ring and stationary ring assembly can adjust the collective pitch angles of the upper and lower rotor assembly blades simultaneously and in the same direction through the pitch rod.

[0014] Beneficial effects: The transmission shaft and speed change mechanism of a conventional coaxial twin-rotor helicopter account for about 15% of the total weight of the machine. The variable-pitch shaftless twin-rotor ducted device of the present invention eliminates the transmission shaft and speed change mechanism of the conventional rotor, has a compact structure, and effectively reduces weight, vibration and noise.

[0015] In actual use, rotor blades operate in a complex aerodynamic environment, and rotor speed frequently changes to control the aircraft's attitude. The present invention's axial hinge design and the dynamic-ring-static-ring structure of the upper and lower rotors enable reliable pitch-change motion for both blades, allowing for timely adjustment of the collective pitch angle to optimize blade operation and improve rotor efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a variable-pitch shaftless twin-rotor duct.

[0017] Figure 2 Schematic diagram of the internal structure of the variable-pitch shaftless twin-rotor culvert.

[0018] Figure markings: 01-duct; 02-upper rotor assembly; 03-lower rotor assembly; 04-moving ring and fixed ring assembly; 05-multi-pole stator; 06-rotor; 07-fixed bearing; 08-shaft journal; 09-radial bearing; 10-thrust bearing; 11-pitch rocker arm; 12-blade; 13-fixed ring; 14-large bearing; 15-moving ring; 16-pitch rod; 17-rod interface; 18-outer wall opening. DETAILED DESCRIPTION

[0019] Example 1. A variable-pitch shaftless twin-rotor ducted device, Figure 1-Figure 2 It is mainly composed of a duct, an upper rotor without a rotor shaft, a lower rotor without a rotor shaft, and a moving ring and a stationary ring assembly.

[0020] Ducted rotors eliminate tip vortices, increase airflow, and generate additional lift. The duct serves as a relatively static component, connected to the aircraft fuselage. The upper and lower rotors have identical diameters, coincident rotational axes, and rotate in opposite directions, offsetting the reaction torques generated by each rotor. The rotating and stationary ring assemblies transmit collective pitch control to the upper and lower rotors via the pitch lever and pitch rocker arm, altering the aerodynamic angle of attack of the upper and lower rotor blades.

[0021] The shape of the duct lip and other parts is designed according to aerodynamic requirements. The inner side is designed with interfaces for installing the upper and lower rotors and the moving and stationary ring components, and the outer side can be connected according to the aircraft structure requirements.

[0022] The upper and lower rotors share the same shaftless structure, primarily consisting of a multi-pole stator, a rotating ring, a fixed bearing, an axial hinge, a variable-pitch rocker arm, and blades. The multi-pole stator is fixed to a mounting interface inside the duct and remains stationary relative to the duct. The rotating ring houses an integrated electric motor rotor, which generates an electromagnetic effect with the multi-pole stator fixed inside the duct, driving the rotating ring and rotor blades. In this example, the rotating ring features three mounting slots for the axial hinge and blades. A fixed bearing, located between the multi-pole stator and the rotating ring, enables relative rotational motion between the two, while also transmitting lift to the rotor. The axial hinge in this example consists of a journal, a radial bearing, and a thrust bearing. The journal is fixedly connected to the blades via blade bolts. Two radial bearings are mounted at the rear end of the journal, enabling variable-pitch motion of the blades relative to the rotating ring while transmitting lift and bending moment. A thrust bearing is also mounted at the rear end of the journal, transferring the centrifugal force of the blades to the rotating ring. The pitch rocker arm is fixedly connected to the journal in the axial hinge. It receives control motion from the rotating and stationary rings via the pitch rod, driving the axial hinge and the blades to change pitch. The blades generate lift and execute control commands, and their tips have a connection to the journal.

[0023] The moving and fixed ring assembly consists of a fixed ring, a large bearing, a moving ring, and a pitch rod. The fixed ring engages with an interface on the inside of the duct and can slide up and down along the duct axis. A rod interface 17 is located on the outside of the fixed ring, extending through an opening in the outer wall of the duct. It can be connected to a servo or control linkage mechanism, receiving control commands to slide up and down. The large bearing is located between the fixed ring and the moving ring, enabling the moving ring to rotate relative to the fixed ring. The outside of the moving ring engages with the large bearing and slides up and down following the fixed ring and the large bearing. The inside of the moving ring has an interface for the pitch rod, which connects to the pitch rocker interface of the upper and lower rotors through the pitch rod, allowing the upper and lower rotors to change pitch simultaneously.

[0024] Example 2. A variable-pitch shaftless twin-rotor ducted device, Figure 1-Figure 2 It is mainly composed of a duct 01, an upper rotor assembly without a rotor shaft 02, a lower rotor assembly without a rotor shaft 03 and a moving ring and a stationary ring assembly 04.

[0025] The lip and other external features of duct 01 are designed to meet aerodynamic requirements. Its interior features interfaces for mounting the upper rotor assembly 02, lower rotor assembly 03, and the dynamic and static ring assemblies 04. As a relatively static component, the exterior of duct 01 can be connected to the aircraft's structural requirements.

[0026] The upper rotor assembly 02 adopts a shaftless design and is mainly composed of a multi-pole stator 05, a rotor 06, a fixed bearing 07, an axial hinge, a pitch rocker arm 11, and blades 12. The multi-pole stator 05 is fixed to the mounting interface on the inside of the duct 01 and is stationary relative to the duct 01. The rotor 06 is integrated with the electric motor rotor, which can generate an electromagnetic effect with the multi-pole stator 05 fixed on the inside of the duct 01, driving the rotor 06 and the rotor blades 12 to rotate. In this example, three mounting slots are provided in the rotor 06 to install the axial hinge and blades 12. The fixed bearing 07 is located between the multi-pole stator 05 and the rotor 06, realizing the relative rotational motion of the multi-pole stator 05 and the rotor 06, while transmitting the lift of the rotor. The axial hinge in this example is composed of a journal 08, a radial bearing 09, and a thrust bearing 10. The journal 08 is fixedly connected to the blade 12 via blade bolts. Two radial bearings 09 are installed at the rear end of the journal to achieve pitch-changing motion of the blade 12 relative to the rotor 06 while transmitting the blade lift and bending moment. At the same time, a thrust bearing 10 is installed at the rear end of the journal 08 to transmit the centrifugal force of the blade 12 to the rotor 06. The pitch-changing rocker arm 11 is fixedly connected to the journal 08 in the axial hinge and can receive the manipulation movement of the dynamic ring and fixed ring assembly 04 through the pitch-changing pull rod 16, and drive the axial hinge and the blade 12 to change pitch. The blade 12 generates lift and executes manipulation commands, and has a connection interface with the journal 08 at the blade tip.

[0027] The structure of the lower rotor assembly 03 is the same as that of the upper rotor assembly 02. The two have the same diameter, the rotation axis coincides, and the rotation directions are opposite. The counter-torques generated by the two rotors cancel each other out.

[0028] The rotating and fixed ring assembly 04 consists of a fixed ring 13, a large bearing 14, a rotating ring 15, and a pitch control rod 16. The fixed ring 13 engages with an interface on the inside of the duct 01, allowing it to slide up and down along the duct's axis. A rod interface 17 extends from the outside of the fixed ring 13 through an opening in the outer wall of the duct 01. This interface connects to a servo or control linkage mechanism, responding to control commands to slide up and down. The large bearing 14 is located between the fixed ring 13 and the rotating ring 15, enabling the rotating ring 15 to rotate relative to the fixed ring 13. The outer side of the rotating ring 15 engages with the large bearing 14, sliding up and down along with the fixed ring 13 and the large bearing 14. The inner side of the rotating ring 15 has an interface for the pitch control rod 16, which connects to the pitch control rocker arms 11 of the upper and lower rotor assemblies 02 and 03, enabling simultaneous pitch control of the upper and lower rotor assemblies 02 and 03.

Claims

1. A variable-pitch shaftless twin-rotor ducted device, characterized in that: The duct comprises an upper rotor assembly without a rotor shaft, a moving ring and a fixed ring assembly, and a lower rotor assembly without a rotor shaft, which are sequentially distributed along the axial direction on the inner side of the duct; the upper rotor assembly comprises a multi-pole stator installed on the inner side of the duct, which is connected to the rotor through a fixed bearing, and the rotor is connected to the blade in the circumferential direction; the moving ring and the fixed ring assembly comprises a fixed ring installed on the inner side of the duct and capable of sliding along the axial direction, which is connected to the moving ring through a large bearing, and a pull rod interface is provided on the circumference of the fixed ring, which extends through the outer wall opening of the duct; the tip of the blade is provided with a pitch rocker arm, which can change the pitch of the blade. The pitch rocker arm is connected to the dynamic ring through the pitch rod; the blade is connected to the rotor through the axial hinge; the axial hinge consists of a shaft neck, a radial bearing and a thrust bearing, and the shaft neck and the blade are fixedly connected by blade bolts; two radial bearings are installed at the rear end of the shaft neck to realize the pitch movement of the blade relative to the rotor while transmitting the lift and bending moment of the blade; at the same time, a thrust bearing is also installed at the rear end of the shaft neck to transmit the centrifugal force of the blade to the rotor; the structure of the upper and lower rotor assemblies is the same; the rotation axes of the blades of the upper and lower rotor assemblies coincide, and the rotation directions are opposite, and the counter-torques generated by each offset each other.

2. The variable pitch shaftless twin-rotor ducted device according to claim 1, characterized in that: The tip of the blade is rotatably connected to the rotor.

3. The variable pitch shaftless twin-rotor ducted device according to claim 1, characterized in that: One end of the pitch-changing rocker arm close to the leading edge of the blade is hinged to the pitch-changing pull rod.

4. The variable pitch shaftless twin-rotor ducted device according to claim 1, characterized in that: The lip shape of the duct is designed according to aerodynamic requirements.

5. The variable pitch shaftless twin-rotor ducted device according to claim 1, characterized in that: The upper rotor assembly has three blades.

6. The variable pitch shaftless twin-rotor ducted device according to claim 1, characterized in that: The moving ring and the stationary ring assembly can adjust the collective pitch angles of the upper and lower rotor assembly blades simultaneously and in the same direction through the pitch-changing pull rod.

Images