Rotor craft and control method thereof

Abstract

The invention belongs to an aircraft structure, and provides a rotor aircraft and a control method thereof in order to solve the technical problem that in an existing rotor aircraft, the prior art still cannot meet the high-performance requirements for main rotor adjustment and power transmission, and the rotor aircraft comprises a fuselage, a tilting assembly, a rotor assembly, a driving assembly and a transmission shaft assembly in the driving assembly. The inner surface of the outer shaft and the outer surface of the inner shaft are each provided with the two spiral grooves with the phase difference of 90 degrees, the multiple rolling pieces are installed at the intersection points of the inner spiral grooves and the outer spiral grooves, and through the structure that the rolling pieces are installed in the spiral grooves, the transmission gap is reduced, and the response speed and the control precision are improved. Due to the design of the two spiral grooves with the phase difference of 90 degrees, transmission between the outer shaft and the inner shaft is stable, and disengagement is avoided. Therefore, the transmission shaft assembly is stable and smooth in transmission, not prone to abrasion and high in transmission precision.

Description

Technical Field

[0001] This application pertains to an aircraft structure, specifically relating to a rotorcraft and its control method. Background Technology

[0002] In the operation of rotorcraft such as helicopters and tiltrotor aircraft, the key to switching between vertical takeoff and landing and cruise flight modes lies in the precise adjustment of the main rotor tilt angle. The power transmission efficiency of the main rotor directly determines the reliability of the tilt angle adjustment and the aircraft's flight performance. However, the current mainstream fixed-shaft or spline telescopic shaft transmission structures have revealed a series of technical problems that urgently need to be solved in practical applications: (1) Insufficient transmission accuracy. The clearance between the traditional fixed shaft and the spline telescopic shaft is relatively large, which cannot meet the stringent requirements of the main rotor tilt angle adjustment for transmission accuracy. This will not only cause obvious vibration during power transmission, but also be accompanied by continuous noise, which will affect the operational stability of the aircraft and exacerbate the fatigue wear of the components.

[0003] (2) Significant contradiction between reversing impact and control accuracy. During the reversing phase of main rotor tilt adjustment, the traditional structure will generate a large impact load. This impact not only disrupts the stability of the flight process, but also interferes with the control accuracy of tilt adjustment, causing the main rotor to be unable to reach the target angle quickly and accurately, thus affecting the response efficiency of flight mode switching.

[0004] (3) High risk of power transmission interruption. Gear transmission is an important part of traditional power transmission, but during the tilting of the main rotor, the gear meshing state is easily affected by the tilt angle change, and disengagement occurs frequently. Once disengagement occurs, it will directly lead to power transmission interruption, which poses a serious threat to the flight safety of the aircraft.

[0005] To address the aforementioned issues, existing technologies have attempted to optimize the system by improving the spline shaft lubrication structure and adding auxiliary support components. However, these solutions only address specific problems locally and cannot meet the high-performance requirements of rotorcraft for main rotor adjustment and power transmission. Summary of the Invention

[0006] This application addresses the technical problem that existing technologies in conventional rotorcraft still cannot meet the high-performance requirements for main rotor adjustment and power transmission, and proposes a rotorcraft and its control method.

[0007] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application proposes a rotorcraft, including a fuselage, a tilting assembly, a rotor assembly, and a drive assembly; both the drive assembly and the tilting assembly are mounted on the fuselage. The drive assembly includes a rotary drive assembly, a telescopic drive assembly, a transmission shaft assembly, and a main shaft; The drive shaft assembly includes an inner shaft and an outer shaft coaxially fitted together, and multiple rolling elements; the inner surface of the outer shaft has two inner helical grooves with a 90° phase difference; the outer shaft is connected to the output end of the rotary drive assembly; the outer surface of the inner shaft has two outer helical grooves with a 90° phase difference; the inner and outer helical grooves rotate in opposite directions, and the inner and outer helical grooves correspond and adapt to each other; the inner shaft is connected to the output end of the telescopic drive assembly. The inner shaft is connected to the main shaft and is used to drive the main shaft to rotate; The rotor assembly is mounted on the output end of the main shaft and the tilt assembly.

[0008] Furthermore, it also includes a cage; the cage is installed between the inner shaft and the outer shaft, and the cage has a rolling element mounting groove, in which the rolling element is installed; The cage is provided with an oil channel for delivering lubricating medium to the rolling elements.

[0009] Furthermore, the cage includes a plurality of sub-cages; the plurality of sub-cages are evenly distributed along the axial direction.

[0010] Furthermore, the tilting assembly includes a base, a tilting drive, and a tilting disk; The base is mounted on the machine body; The tilting drive is mounted on the base, and its output end is connected to the tilting disk to drive the tilting disk to tilt. The tilting disk is mounted on the outside of the main shaft through a bearing sleeve.

[0011] Furthermore, the tilting assembly also includes a tilting disc telescopic compensation assembly; the tilting drive is a hydraulic drive structure; The tilting disc telescopic compensation assembly includes a hydraulic cylinder holder and a hydraulic cylinder. The hydraulic cylinder holder is mounted on a base, and the hydraulic cylinder is installed inside the hydraulic cylinder holder. A hydraulic rod extending from the hydraulic cylinder is hinged to the tilting disc. The hydraulic rod and the hydraulic cylinder holder are connected by a linear bearing.

[0012] Furthermore, the main shaft and the inner shaft are arranged perpendicularly; A first spherical gear is provided at one end of the main shaft near the inner shaft, and a second spherical gear is provided at one end of the inner shaft near the main shaft; the first spherical gear and the second spherical gear mesh with each other.

[0013] Furthermore, it also includes the bearing housing; The output end of the telescopic drive assembly is provided with a mounting joint, which is sleeved on the outside of the inner shaft, and the mounting joint and the inner shaft are connected by a first angular contact bearing. The bearing housing is sleeved and installed outside the output end of the telescopic drive assembly, and the output end of the telescopic drive assembly is connected to the bearing housing through a second angular contact bearing.

[0014] Furthermore, it also includes a first retaining ring and a second retaining ring; The first snap ring is mounted on the inner shaft, and the second snap ring is mounted on the bearing seat of the second angular contact bearing; the first snap ring and the second snap ring are used to define the axial positions of the first angular contact bearing and the second angular contact bearing, respectively.

[0015] Furthermore, a first limiting step is provided on the inner shaft; a second limiting step is provided on the outer wall of the output end of the second angular contact telescopic drive assembly; The first angular contact bearing is installed between the first limiting step and the first retaining ring; The second angular contact bearing is installed between the second limiting step and the second snap ring.

[0016] Secondly, this application also proposes a control method for the aforementioned rotorcraft, comprising: The inner shaft extends and retracts via a telescopic drive assembly, the outer shaft rotates via a rotation drive assembly, and the rotor assembly tilts via a tilting assembly. Compared with the prior art, this application has the following advantages: This application proposes a rotorcraft, including a fuselage, a tilting assembly, a rotor assembly, and a drive assembly. The drive assembly includes a transmission shaft assembly with two helical grooves, each 90° out of phase, on both the inner and outer surfaces of the outer shaft. Multiple rolling elements are installed at the intersection of the inner and outer helical grooves. This structure, by installing rolling elements within the helical grooves, reduces transmission backlash and improves response speed and control precision. The 90° phase difference between the two helical grooves ensures smooth transmission between the outer and inner shafts, preventing disengagement. Therefore, the transmission shaft assembly proposed in this application provides stable and smooth transmission, is less prone to wear, and offers high transmission precision. It is more suitable for applications requiring high loads, long operating cycles, and high reliability. When the tilting assembly controls the rotor assembly's tilt, the telescopic drive assembly can drive the inner shaft to extend or retract, ensuring stable tilt control and stable rotation of the main shaft, while simultaneously meeting the high-performance requirements for main rotor adjustment and power transmission.

[0017] This application also proposes a control method for a rotorcraft that possesses all the advantages of the aforementioned rotorcraft. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an outer spiral groove on an inner shaft of a transmission shaft assembly embodiment of this application; Figure 2 This is a schematic diagram of an inner spiral groove on an outer shaft of a transmission shaft assembly embodiment of this application; Figure 3 This is a schematic diagram of the installation of the rolling element in an embodiment of the drive shaft assembly of this application; Figure 4 This is a schematic diagram of the sub-cage in an embodiment of the drive shaft assembly of this application; Figure 5 This is a schematic diagram showing the installation of the first angular contact bearing and the second angular contact bearing in an embodiment of the telescopic drive structure of this application; Figure 6 This is a schematic diagram of the tilting assembly and drive shaft assembly in the rotorcraft embodiment of this application; Figure 7 This is a schematic diagram of the tilting disc telescopic compensation assembly in the rotorcraft embodiment of this application.

[0020] Wherein: 1-rolling element, 2-outer shaft, 3-inner shaft, 4-inner helical groove, 5-outer helical groove, 6-cage, 7-rolling element mounting groove, 8-sub-cage, 9-rotation drive assembly, 10-telescopic drive assembly, 11-first angular contact bearing, 12-second angular contact bearing, 13-first snap ring, 14-second snap ring, 15-bearing housing, 16-first limiting step, 17-second limiting step, 18-mounting joint, 19-rotor of the rotary motor, 20-oil seal, 21-output end of the telescopic drive assembly, 22-tilting assembly, 23-main shaft, 24-base, 25-tilting drive component, 26-tilting disc, 27-bearing, 28-hydraulic cylinder cage, 29-inner shaft support, 31-hydraulic rod, 32-spherical bearing, 34-first spherical gear, 35-second spherical gear, 36-stator and fixing frame of the rotary motor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application 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, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0026] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 mechanical connection or an electrical 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 application according to the specific circumstances.

[0027] Rotary-wing aircraft are widely used in many key fields such as aerospace, civil transportation, emergency rescue, and military operations. Helicopters, with their ability to take off and land vertically without a runway, play an irreplaceable role in urban air traffic, mountain rescue, and emergency medical transport. Tiltrotor aircraft combine the vertical takeoff and landing capabilities of helicopters with the high-speed cruise advantages of fixed-wing aircraft, and are often used for long-range material delivery, long-distance search and rescue, and military reconnaissance missions. In these applications, aircraft need to frequently switch between vertical takeoff and landing and cruise flight modes, and the core of this switching lies in the precise control of the main rotor. As a key component generating lift and propulsion, the reliability of the main rotor's control directly affects the aircraft's flight safety and operational efficiency, all of which depend on a stable and efficient power transmission system. Currently, the industry mainstream uses fixed-shaft or spline telescopic shafts as the main rotor's power transmission structure. These structures have provided basic support for meeting flight requirements in different scenarios in long-term practical applications. However, as the requirements for flight accuracy, stability, and load capacity of aircraft continue to increase, their potential technical shortcomings are gradually becoming apparent.

[0028] In the aforementioned application scenarios, the current mainstream power transmission and tilt adjustment structures reveal numerous problems affecting aircraft performance. Firstly, there is the issue of insufficient transmission precision. A significant clearance exists between the fixed shaft and the spline telescopic shaft during their fit, while main rotor tilt adjustment demands extremely high transmission precision. This clearance leads to noticeable vibration during power transmission, accompanied by continuous noise. Vibration not only disrupts the aircraft's stability during flight, worsening the experience for passengers, but also exacerbates fatigue wear on various components, shortening their lifespan and increasing maintenance frequency and costs. Secondly, the conflict between reversing impact and control precision is significant. During the reversing phase of main rotor tilt adjustment, traditional structures generate substantial impact loads. This impact directly affects flight stability, especially in scenarios with extremely high flight stability requirements, such as emergency rescue, potentially leading to risks such as swaying rescue supplies or shifting medical equipment. Simultaneously, the impact interferes with the control precision of tilt adjustment, preventing the main rotor from quickly and accurately adjusting to the target angle, prolonging flight mode switching time, reducing the aircraft's adaptability to complex environments, and impacting mission execution efficiency. Finally, the risk of power transmission interruption is high. In traditional power transmission systems, gear transmission is an important component. Gear transmission is widely used due to its high transmission efficiency and wide applicability. However, during the tilting of the main rotor, the change in tilt angle will affect the meshing state between gears, which can easily lead to gear disengagement. Once disengagement occurs, power transmission will be directly interrupted. For aircraft in flight, power interruption may cause serious safety accidents such as stall and crash, posing a great threat to the lives of the crew and the safety of the equipment.

[0029] While existing improvement solutions can alleviate some problems to a certain extent, they still have significant limitations and cannot fundamentally meet the high-performance requirements of rotorcraft for main rotor adjustment and power transmission. For example, improving the spline shaft lubrication structure can only improve the problem of insufficient lubrication, but cannot solve the problems of insufficient transmission accuracy and reversing impact; adding auxiliary support structures can reduce vibration to some extent, but it does not improve the risk of power interruption due to gear disengagement. These localized improvement solutions not only fail to address all technical pain points, but may also introduce new failure risks due to compatibility issues between the new structures and the original system. For example, the newly added lubrication storage tank may leak lubricating oil due to machining accuracy issues, and the additional support brackets may increase structural weight, affecting the overall load capacity of the aircraft.

[0030] In summary, existing technologies still cannot completely solve core problems such as transmission accuracy, commutation impact, and power interruption, which restricts the application and development of rotorcraft in more complex and demanding scenarios. Therefore, the industry urgently needs a new power transmission and tilt adjustment technology solution that can comprehensively solve the above problems.

[0031] Based on the above, this application proposes a rotorcraft and its control method, which achieves high precision, low impact, and good lubrication while ensuring continuous power transmission.

[0032] As one embodiment of the rotorcraft of this application, it includes a fuselage, a tilting assembly 22, a rotor assembly, and a drive assembly. Both the drive assembly and the tilting assembly 22 are mounted on the fuselage. The drive assembly includes a rotary drive assembly 9, a telescopic drive assembly 10, a transmission shaft assembly, and a main shaft 23. The transmission shaft assembly includes an inner shaft 3 and an outer shaft 2 coaxially fitted together, and multiple rolling elements 1. Two inner helical grooves 4 with a 90° phase difference are formed on the inner surface of the outer shaft 2. The outer shaft 2 is connected to the output end of the rotary drive assembly 9. Two outer helical grooves 5 with a 90° phase difference are formed on the outer surface of the inner shaft 3. The inner helical grooves 4 and outer helical grooves 5 rotate in opposite directions, and the inner helical grooves 4 and outer helical grooves 5 correspond and adapt to each other. The inner shaft 3 is connected to the output end 21 of the telescopic drive assembly. The inner shaft 3 is connected to the main shaft 23 and is used to drive the main shaft 23 to rotate. The rotor assembly is mounted on the main shaft 23 and the output end of the tilting assembly 22.

[0033] It should be noted that the drive assembly simultaneously realizes the transmission of rotational power and the adjustment of axial extension. The rotational drive assembly 9 provides the torque required for the rotor to rotate, and the extension drive assembly 10 adjusts the rotor tilt angle in conjunction with the tilting assembly 22 through axial movement. The transmission shaft assembly, as an intermediate carrier, accurately transmits the two powers to the main shaft 23, ensuring that the power is uninterrupted and the movement is not interfered with.

[0034] like Figure 1The diagram shown is a schematic representation of the outer spiral groove 5 on the inner shaft 3 of an embodiment of the transmission shaft assembly of this application. Figure 2 The diagram shows an inner helical groove 4 on an outer shaft 2 according to an embodiment of the transmission shaft assembly of this application. The inner shaft 3 and the outer shaft 2 are coaxially fitted to ensure that their axes are aligned and to avoid misalignment during movement that could lead to jamming or wear. In this invention, the outer shaft 2 can rotate after receiving power from the rotary drive assembly 9, and the inner helical groove 4 on its inner side will push the rolling element 1 as it rotates. Since the rolling element 1 is in contact with the outer helical groove 5 of the inner shaft 3 at the same time, it will transmit the rotational force of the outer shaft 2 to the inner shaft 3, causing the inner shaft 3 to rotate in the same direction as the outer shaft 2. At the same time, the inner shaft 3 is also connected to the telescopic drive assembly 10. During the rotation in the same direction, the telescopic drive assembly 10 can control the inner shaft 3 to extend or retract along the axial direction, or when the inner shaft 3 is subjected to external force and needs to extend or retract, it can also complete linear motion while maintaining rotation in the same direction, and there will be no situation where the inner shaft 3 and the outer shaft 2 rotate in opposite directions.

[0035] The outer helical groove 5 of the inner shaft 3 and the inner helical groove 4 of the outer shaft 2 are paired and rotate in the same direction. Their helical parameters are perfectly matched, which not only forms a rolling channel to accommodate the rolling element 1, but also ensures that the rotational force is transmitted in the same direction. When the outer shaft 2 rotates, the inner helical groove 4 pushes the rolling element 1 to roll in the channel, and the rolling element 1 will generate a thrust in the same direction on the outer helical groove 5. This thrust can be decomposed into two components: one is a component along the circumference of the inner shaft 3, which drives the inner shaft 3 to rotate in the same direction as the outer shaft 2; the other is a component along the axis of the inner shaft 3, which, with the cooperation of the telescopic drive assembly 10, drives the inner shaft 3 to perform linear telescopic motion. Conversely, when the inner shaft 3 needs to be telescopicated by external force, the outer helical groove 5 will push the rolling element 1 to roll, which in turn drives the inner helical groove 4 of the outer shaft 2 to rotate in the same direction, ensuring that the inner shaft 3 and the outer shaft 2 always rotate in the same direction and will not be in opposite directions. Throughout the entire operation, the rolling element 1 not only converts the sliding friction between the inner shaft 3 and the outer shaft 2 into rolling friction, reducing resistance, but also accurately transmits the rotation direction, ensuring that the inner shaft 3 and the outer shaft 2 rotate in the same direction.

[0036] In terms of motion accuracy, since the inner shaft 3 and outer shaft 2 always rotate in the same direction, the entire transmission structure will not experience accuracy deviations due to conflicting rotational directions during the combined motion of rotation and linear extension, meeting the requirements of high-precision equipment. Regarding power transmission efficiency, the characteristic of the rolling element 1 converting sliding friction into rolling friction, combined with the absence of reverse force loss during rotation in the same direction, improves overall transmission efficiency. The direct power transmission between the inner shaft 3 and outer shaft 2 and the rolling element 1 also reduces intermediate transmission links, further lowering power loss. Furthermore, the double-helix groove design with a 90° phase difference evenly distributes the pressure on the rolling element 1, reducing localized wear and thus effectively extending its service life.

[0037] In some embodiments of this application, the drive shaft assembly further includes a retainer 6, which is installed between the inner shaft 3 and the outer shaft 2. The retainer 6 has a rolling element mounting groove 7, in which the rolling element 1 is installed. The retainer 6 is installed between the inner shaft 3 and the outer shaft 2, and its main function is to position the rolling element 1 and provide a lubrication channel. First, the rolling element mounting groove 7 on the retainer 6 accommodates each rolling element 1 individually, preventing multiple rolling elements 1 from colliding and squeezing at the intersection of the inner spiral groove 4 and the outer spiral groove 5. This ensures that each rolling element 1 can roll smoothly on a preset trajectory, especially when the inner shaft 3 and the outer shaft 2 rotate in the same direction, preventing transmission jamming caused by centrifugal force offset of the rolling element 1. In addition, the retainer 6 itself provides a lubrication channel. When the rolling element 1 rolls in the rolling element mounting groove 7, the retainer 6 slowly releases lubricating oil or grease, evenly coating the contact surface between the rolling element 1 and the spiral groove, continuously reducing frictional resistance and preventing damage to parts caused by dry friction. Figure 3 The diagram shown is a schematic representation of the installation of the rolling element 1 in an embodiment of the drive shaft assembly of this application. Figure 4 The diagram shown is a schematic representation of the sub-cage 8 in an embodiment of the drive shaft assembly of this application. In practical applications, to further reduce weight, the cage 6 may include multiple sub-cages 8, which are evenly spaced along the axial direction. It should be noted that the number and size of the sub-cages 8 can be adjusted according to actual processing and usage needs, thereby reducing weight and enabling the structure of this application to have a wider range of applications.

[0038] In some embodiments of this application, the rolling element 1 may be a ball bearing. It may also be replaced with other rolling element structures depending on the actual situation, and the material may be adjusted according to usage requirements.

[0039] In this application, the inner shaft 3 is connected to the main shaft 23, and the rotor assembly is installed on the output end of the main shaft 23 and the tilting assembly 22. After the rotation drive assembly 9 drives the inner shaft 3 to rotate, the main shaft 23 drives the rotor assembly to rotate, and the tilting assembly 22 can adjust the tilt of the rotor assembly.

[0040] In some embodiments of this application, the tilting assembly 22 includes a base 24, a tilting drive 25, and a tilting disk 26. The base 24 is mounted on the fuselage, and the tilting drive 25 is mounted on the base 24. The output end of the tilting drive 25 is connected to the tilting disk 26 to drive the tilting disk 26 to tilt. The tilting disk 26 is mounted on the outside of the main shaft 23 via a bearing 27. The tilting assembly 22 achieves tilt angle adjustment of the rotor assembly without affecting the rotational power transmission of the main shaft 23. The base 24 serves as a fixed foundation, providing a stable mounting platform for the tilting drive 25. The output torque of the tilting drive 25 drives the tilting disk 26 to rotate around the tilting axis. The tilting disk 26 is fitted with the main shaft 23 via the bearing 27, allowing it to tilt with the tilting drive 25 while also allowing the main shaft 23 to rotate independently at high speed. Finally, through the connection between the tilting disk 26 and the rotor assembly, the tilt angle of the rotor assembly is changed.

[0041] like Figure 6 The diagram shown is a structural schematic of the tilting assembly 22 and the drive shaft assembly in an embodiment of the rotorcraft of this application. Figure 7 The diagram shown is a structural schematic of the tilt disk telescopic compensation assembly in an embodiment of the rotorcraft of this application. The tilt drive 25 is a hydraulic drive structure, and the tilt assembly 22 also includes the tilt disk telescopic compensation assembly. The tilt disk telescopic compensation assembly includes a hydraulic cylinder holder 28 and a hydraulic cylinder. The hydraulic cylinder holder 28 is mounted on the base 24, and the hydraulic cylinder is installed inside the hydraulic cylinder holder 28. The hydraulic rod 31 extending from the hydraulic cylinder is hinged to the tilt disk 26, and the hydraulic rod 31 and the hydraulic cylinder holder 28 are connected by a linear bearing. It should be noted that the hinge between the hydraulic rod 31 and the tilt disk 26 can be achieved by a spherical bearing 32, and the selection of the spherical bearing 32 can be adjusted according to actual usage requirements. The tilting disc telescopic compensation assembly addresses the positional changes of the tilting disc 26 during tilting. When the tilting drive 25 drives the tilting disc 26 to rotate around the tilting axis, the tilting disc 26 will experience axial or radial positional displacement. At this time, the hydraulic cylinder, through the extension and retraction of the hydraulic rod 31, in conjunction with the hinge structure with the tilting disc 26, compensates for this displacement in real time, preventing the tilting disc 26 from jamming or experiencing additional stress due to positional deviation. The tilting disc telescopic compensation assembly can control the angle of the tilting disc 26, and the linear bearing can share the lateral force of the hydraulic cylinder. The linear bearing between the hydraulic rod 31 and the hydraulic cylinder cage 28 ensures that the hydraulic rod 31 slides in a fixed direction during extension and retraction, improving the stability and accuracy of the compensation action.

[0042] The main shaft 23 and the inner shaft 3 are arranged perpendicularly. A first spherical gear 34 is located at the end of the main shaft 23 near the inner shaft 3, and a second spherical gear 35 is located at the end of the inner shaft 3 near the main shaft 23. The first spherical gear 34 and the second spherical gear 35 mesh with each other. To ensure the installation stability of the inner shaft 3, an inner shaft bracket 29 can also be provided to mount the inner shaft 3. The perpendicular arrangement of the main shaft 23 and the inner shaft 3 solves the power transmission problem of spatially intersecting shafts. The tooth surface of the spherical gear is designed as a spherical surface, which can achieve a larger deflection angle compared with ordinary cylindrical gears. When the tilting component 22 drives the main shaft 23 to tilt, the first spherical gear 34 deflects with the main shaft 23, and the second spherical gear 35 can adaptively adjust its position through the meshing of the spherical tooth surfaces to ensure stable meshing during the deflection process and to prevent interruption of power transmission. At the same time, the meshing method of the spherical gears can absorb the installation deviation between the main shaft 23 and the inner shaft 3, improving the transmission fault tolerance. The hydraulic cylinder solves the problem that when the tilting disc 26 tilts, the trajectory of the first spherical gear 34 is arc-shaped, thus disengaging from the second spherical gear 35, ensuring that the movement trajectory of the first spherical gear 34 is a straight line when tilting.

[0043] This invention achieves a shock-free combination of power transmission and axial extension through a designed drive shaft assembly. Uninterrupted power transmission during tilting is achieved via spherical gears and hydraulic compensation, offering advantages such as high transmission precision, excellent lubrication, and strong reliability. It is particularly suitable for vertical takeoff and landing (VTOL) aircraft, such as tiltrotor aircraft and compound-wing UAVs. During VTOL, the main rotor surface is parallel to the fuselage, providing lift. During cruise, the main rotor tilts backward, utilizing the airflow to generate thrust, achieving efficient flight.

[0044] Furthermore, this application integrates the rotary drive, telescopic drive, and transmission shaft into one unit, eliminating the need for additional transmission intermediaries, reducing power transmission links, and improving overall drive efficiency. The targeted connection between the rotary drive assembly 9 and the outer shaft 2, and the telescopic drive assembly 10 and the inner shaft 3, ensures precise power transmission. The inner shaft 3 can simultaneously achieve unidirectional rotation and linear telescopic extension, meeting the needs of complex motion.

[0045] As an example, the outer shaft 2 is connected to the rotary drive assembly 9, which uses a rotary motor. The rotor 19 of the rotary motor is installed in the stator and fixed frame 36 of the rotary motor. The rotary motor drives the outer shaft 2 to rotate. The telescopic drive assembly 10 uses a hydraulic telescopic assembly to push the inner shaft 3 to move axially.

[0046] like Figure 5The diagram shows the installation of the first angular contact bearing 11 and the second angular contact bearing 12 in an embodiment of the telescopic drive structure of this application. As an example, it also includes a bearing housing 15, a first retaining ring 13, and a second retaining ring 14. The output end 21 of the telescopic drive assembly is provided with a mounting joint 18, which is sleeved on the outside of the inner shaft 3. The mounting joint 18 and the inner shaft 3 are connected via the first angular contact bearing 11. The bearing housing 15 is sleeved on the outside of the output end 21 of the telescopic drive assembly, and the output end 21 of the telescopic drive assembly is connected to the bearing housing 15 via the second angular contact bearing 12. Furthermore, to ensure the axial positioning of the first angular contact bearing 11 and the second angular contact bearing 12, the inner shaft 3 is provided with a first limiting step 16, and the outer wall of the output end 21 of the second angular contact telescopic drive assembly is provided with a second limiting step 17. The first angular contact bearing 11 is installed between the first limiting step 16 and the first retaining ring 13, and the second angular contact bearing 12 is installed between the second limiting step 17 and the second retaining ring 14. An oil seal 20 is provided at one end of the bearing housing 15 near the telescopic drive assembly 10.

[0047] The mounting joint 18 is fitted onto the outside of the inner shaft 3, serving as a transition between the output end 21 of the telescopic drive assembly and the inner shaft 3. The first angular contact bearing 11 between the mounting joint 18 and the inner shaft 3 allows the inner shaft 3 to rotate freely within the mounting joint 18 while also bearing the radial and axial loads generated during the telescopic extension and retraction of the inner shaft 3. The second angular contact bearing 12 between the output end 21 of the telescopic drive assembly and the bearing housing 15 can also bear radial and axial loads, ensuring smooth relative rotation between the bearing housing 15 and the output end of the telescopic drive assembly 10. To achieve axial positioning of the angular contact bearing 27, the first limiting step 16 on the inner shaft 3 provides one-end support for the first angular contact bearing 11. After the first retaining ring 13 is engaged in the retaining groove of the inner shaft 3, it presses against the first angular contact bearing 11 from the other end, fixing it between the first limiting step 16 and the first retaining ring 13. The second limiting step 17 on the outer wall of the output end of the telescopic drive assembly 10 supports one end of the second angular contact bearing 12. The second retaining ring 14 is engaged with the retaining groove of the bearing housing 15, fixing the second angular contact bearing 12 from the other end and preventing the bearing 27 from moving axially. The oil seal 20 of the bearing housing 15 near the end of the telescopic drive assembly 10, together with the dust cover, can seal the internal space of the bearing housing 15 to prevent internal lubricating oil leakage, while blocking external dust and moisture from entering, thus preventing wear of the bearing 27.

[0048] In addition, this application also proposes a control method for the above-mentioned rotorcraft, which may include: The inner shaft 3 is extended and retracted by the telescopic drive assembly 10, the outer shaft 2 is rotated by the rotation drive assembly 9, and the rotor assembly is tilted by the tilting assembly 22, thereby completing the corresponding drive.

[0049] The above are merely preferred embodiments of this application and are 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 rotorcraft, comprising a fuselage, a tilting assembly (22), a rotor assembly, and a drive assembly; characterized in that: Both the drive assembly and the tilting assembly (22) are mounted on the fuselage; The drive assembly includes a rotary drive assembly (9), a telescopic drive assembly (10), a transmission shaft assembly, and a main shaft (23); The drive shaft assembly includes an inner shaft (3) and an outer shaft (2) coaxially fitted together, and a plurality of rolling elements (1); the inner surface of the outer shaft (2) is provided with two inner spiral grooves (4) with a phase difference of 90°; the outer shaft (2) is connected to the output end of the rotary drive assembly (9); the outer surface of the inner shaft (3) is provided with two outer spiral grooves (5) with a phase difference of 90°; the inner spiral grooves (4) and the outer spiral grooves (5) have opposite rotation directions, and the inner spiral grooves (4) and the outer spiral grooves (5) are corresponding and adapted to each other; the inner shaft (3) is connected to the output end (21) of the telescopic drive assembly; The inner shaft (3) is connected to the main shaft (23) and is used to drive the main shaft (23) to rotate; The rotor assembly is mounted on the output end of the main shaft (23) and the tilt assembly (22).

2. The rotorcraft according to claim 1, characterized in that, It also includes a retainer (6); the retainer (6) is installed between the inner shaft (3) and the outer shaft (2), and the retainer (6) has a rolling element mounting groove (7), in which the rolling element (1) is installed; The cage (6) is provided with an oil channel for conveying lubricating medium to the rolling element (1).

3. A rotorcraft according to claim 2, characterized in that, The cage (6) includes a plurality of sub-cages (8); the plurality of sub-cages (8) are evenly distributed along the axial direction.

4. A rotorcraft according to claim 1, characterized in that, The tilting assembly (22) includes a base (24), a tilting drive (25), and a tilting disk (26); The base (24) is mounted on the machine body; The tilt drive (25) is mounted on the base (24), and the output end of the tilt drive (25) is connected to the tilt disk (26) to drive the tilt disk (26) to tilt; the tilt disk (26) is mounted on the outside of the main shaft (23) through a bearing (27).

5. A rotorcraft according to claim 4, characterized in that, The tilting assembly (22) also includes a tilting disc telescopic compensation assembly; the tilting drive (25) is a hydraulic drive structure; The tilting disc telescopic compensation assembly includes a hydraulic cylinder holder (28) and a hydraulic cylinder. The hydraulic cylinder holder (28) is mounted on the base (24), and the hydraulic cylinder is mounted inside the hydraulic cylinder holder (29). The hydraulic rod (31) extending from the hydraulic cylinder is hinged to the tilting disc (26). The hydraulic rod (31) and the hydraulic cylinder holder (28) are connected by a linear bearing.

6. A rotorcraft according to claim 5, characterized in that, The main shaft (23) and the inner shaft (3) are arranged perpendicularly; The main shaft (23) is provided with a first spherical gear (34) at one end near the inner shaft (3), and the inner shaft (3) is provided with a second spherical gear (35) at one end near the main shaft (23); the first spherical gear (34) and the second spherical gear (35) mesh with each other.

7. A rotorcraft according to claim 1, characterized in that, It also includes the bearing housing (15); The output end (21) of the telescopic drive assembly is provided with a mounting joint (18), which is sleeved on the outside of the inner shaft (3). The mounting joint (18) and the inner shaft (3) are connected by a first angular contact bearing (11). The bearing housing (15) is sleeved and installed outside the output end (21) of the telescopic drive assembly. The output end (21) of the telescopic drive assembly and the bearing housing (15) are connected by a second angular contact bearing (12).

8. A rotorcraft according to claim 7, characterized in that, It also includes a first retaining ring (13) and a second retaining ring (14); The first snap ring (13) is mounted on the inner shaft (3), and the second snap ring (14) is mounted on the bearing (27) seat of the second angular contact bearing (12); the first snap ring (13) and the second snap ring (14) are used to define the axial positions of the first angular contact bearing (11) and the second angular contact bearing (12), respectively.

9. A rotorcraft according to claim 8, characterized in that, The inner shaft (3) is provided with a first limiting step (16); the outer wall of the output end (21) of the second angular contact telescopic drive assembly is provided with a second limiting step (17); The first angular contact bearing (11) is installed between the first limiting step (16) and the first retaining ring (13); The second angular contact bearing (12) is installed between the second limiting step (17) and the second snap ring (14).

10. A control method for a rotorcraft according to any one of claims 1 to 9, characterized in that, include: The inner shaft (3) is extended and retracted by the telescopic drive assembly (10), the outer shaft (2) is rotated by the rotation drive assembly (9), and the rotor assembly is tilted by the tilt assembly (22).

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