Rotor gearbox apparatus and helicopter

Abstract

A rotor gearbox apparatus, and a helicopter. The rotor gearbox apparatus comprises a rotor assembly, a power input assembly, a tail transmission assembly, and a gearbox assembly. The rotor assembly comprises a rotor shaft. The gearbox assembly comprises a first non-orthogonal face gear and a second non-orthogonal face gear arranged on the rotor shaft, a tip diameter of the first non-orthogonal face gear being smaller than a tip diameter of the second non-orthogonal face gear. The power input assembly comprises a first cylindrical gear meshing with the second non-orthogonal face gear, and the tail transmission assembly comprises a second cylindrical gear meshing with the first non-orthogonal face gear.

Description

A rotor speed reduction device and a helicopter Technical Field

[0001] This application relates to the field of aircraft technology, and in particular to a rotor deceleration device and a helicopter. Background Technology

[0002] Helicopters are currently one of the mainstays of general aviation, typically possessing unique vertical takeoff and landing capabilities. They can hover in the air and fly in any direction—forward, backward, left, and right—and can take off and land on unprepared locations or rooftop platforms, capabilities that fixed-wing aircraft and other modes of transportation cannot match. The helicopter's main gearbox is one of the key transmission components. It reduces the high-speed, low-torque engine power and converts it into low-speed, high-torque power, transmitting it to the rotor shaft and then distributing it to the tail rotor and other components according to speed and torque requirements. Besides transmitting power, the helicopter's main gearbox directly bears all the forces and torques generated by the rotor and transmits them to the fuselage, acting as a central load-bearing component.

[0003] Currently, helicopter main reducers have high power and large transmission ratios. When the rotor shaft is tilted forward, the input shaft is parallel to the tail drive shaft but not orthogonal to the rotor shaft. Therefore, a transmission form using non-orthogonal bevel gears and planetary gears is usually used. However, the combination of non-orthogonal bevel gears and planetary gears has obvious disadvantages: (1) The transmission ratio of a single-stage non-orthogonal bevel gear transmission is generally within 3, which is small. To achieve the goal of a large speed ratio in the main reducer, multiple stages of planetary gears must be connected in series after the non-orthogonal bevel gears, which limits the power density; (2) Bevel gears are usually manufactured and used in pairs. The interchangeability of parts is poor, and they need to be replaced in pairs. The maintenance cost is high, difficult, and the cycle is long; (3) Due to machining errors and installation errors, the cone apex angles cannot be coincident, resulting in an unstable transmission ratio, unstable transmission, and easy fatigue problems; (4) When multiple pairs of bevel gears mesh at the same time, the smaller bevel gears need to bear a large axial force, the bearings bear a large axial force, the support structure is complex, and the installation and adjustment are difficult. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of this application is to provide a rotor deceleration device and a helicopter to solve the above-mentioned shortcomings of the transmission form of the helicopter main deceleration unit which uses a non-orthogonal bevel gear and planetary gear combination in the prior art.

[0005] This application discloses a rotor speed reduction device, including a rotor assembly, a power input assembly, a tail drive assembly, and a speed reduction assembly. The rotor assembly includes a rotor shaft. The speed reduction assembly includes a first non-orthogonal surface gear and a second non-orthogonal surface gear arranged sequentially from top to bottom on the rotor shaft. The tooth surface diameter of the first non-orthogonal surface gear is smaller than that of the second non-orthogonal surface gear. The power input assembly includes a first cylindrical gear that meshes with the second non-orthogonal surface gear. The tail drive assembly includes a second cylindrical gear that meshes with the first non-orthogonal surface gear.

[0006] Optionally, the rotor reduction device further includes a transmission housing disposed on the rotor shaft, and the transmission housing rotates relative to the rotor shaft. The interior of the transmission housing forms a closed accommodating chamber, the reduction assembly is located in the accommodating chamber, and the power input assembly and the tail drive assembly are both disposed on the transmission housing.

[0007] Optionally, the transmission housing includes an upper transmission housing and a lower transmission housing connected to the upper transmission housing. A first assembly channel communicating with the accommodating cavity is provided between the upper transmission housing and the lower transmission housing. The power input assembly also includes a power input shaft disposed in the first assembly channel and an input bearing disposed on the power input shaft. The power input shaft is rotatably connected to the upper transmission housing and the lower transmission housing respectively through the input bearing. The first cylindrical gear is disposed on the inner end of the power input shaft.

[0008] Optionally, the outer end of the power input shaft extends out of the transmission housing along the first assembly channel, and an input flange is provided on the outer end of the power input shaft.

[0009] Optionally, the upper transmission box is provided with a second assembly channel communicating with the accommodating cavity. The tail transmission assembly further includes a tail transmission output shaft disposed in the second assembly channel and an output bearing disposed on the tail transmission output shaft. The tail transmission output shaft is rotatably connected to the upper transmission box through the output bearing. The second cylindrical gear is disposed on the inner end of the tail transmission output shaft.

[0010] Optionally, the outer end of the tail transmission output shaft extends out of the upper transmission box along the second assembly channel, and an output flange is provided on the outer end of the tail transmission output shaft.

[0011] Optionally, the top of the upper transmission half-box is provided with a top guide cylinder that cooperates with the rotor shaft, and the bottom of the lower transmission half-box is provided with a bottom guide cylinder that cooperates with the rotor shaft. The rotor assembly also includes a top rotor bearing and a bottom rotor bearing disposed on the rotor shaft. The rotor shaft is rotatably connected to the top guide cylinder through the top rotor bearing, and the rotor shaft is rotatably connected to the bottom guide cylinder through the bottom rotor bearing.

[0012] Optionally, the second non-orthogonal gear includes a first gear ring, a first transmission ring located below the first gear ring, and a connecting arm connecting the first gear ring and the first transmission ring. A plurality of first gear teeth are arranged circumferentially on the top surface of the first gear ring, and the first gear teeth are non-orthogonal to the central axis of the first gear ring in the horizontal direction.

[0013] The inner diameter of the first transmission ring is smaller than the inner diameter of the first gear ring. A first connecting seat is provided on the shaft wall of the rotor shaft. The first connecting seat is connected to the top surface of the first transmission ring. A plurality of connecting arms are provided along the circumference of the first transmission ring.

[0014] Optionally, the first non-orthogonal gear includes a second gear ring and a second transmission ring located below the second gear ring. The inner diameter of the second transmission ring is smaller than the inner diameter of the second gear ring, and the second gear ring is disposed on the top surface of the second transmission ring. A plurality of second gear teeth are arranged circumferentially on the top surface of the second gear ring, and the second gear teeth are non-orthogonal to the central axis of the second gear ring in the horizontal direction.

[0015] A second connecting seat is provided on the shaft wall of the rotor shaft above the first connecting seat, and the second connecting seat is connected to the bottom surface of the second transmission ring.

[0016] This application also discloses a helicopter employing the aforementioned rotor deceleration device, the helicopter comprising a fuselage and the rotor deceleration device disposed on the fuselage.

[0017] Compared with the prior art, the rotor deceleration device and helicopter provided in this application have the following advantages:

[0018] By installing a power input assembly, a tail rotor assembly, and a reduction assembly on the rotor shaft, and utilizing the meshing connection between a first cylindrical gear and a second non-orthogonal surface gear, the input power is transmitted to the second non-orthogonal surface gear. The second non-orthogonal surface gear then drives the rotor shaft to rotate, thus reducing and reversing the high-speed, low-torque input power into low-speed, high-torque power transmitted to the rotor shaft. Furthermore, the meshing connection between the second cylindrical gear and the first non-orthogonal surface gear, along with the coaxial transmission of the first and second non-orthogonal surface gears, further transmits the input power to the second cylindrical gear, which then outputs it to components such as the tail rotor. Because the tooth diameter of the first non-orthogonal surface gear is small, the input speed can be further reduced. Through two reductions, the tail rotor achieves greater torque and a lower speed, allowing for optimized power distribution between the rotor shaft and the tail rotor. Therefore, applying non-orthogonal surface gears to the main gearbox of helicopters allows for adjustable transmission angles, meeting the design requirements of arbitrary forward tilt angles of the rotor shaft. The use of both cylindrical and surface gears enables a higher overall speed ratio, ensuring stable transmission and effectively improving power density. Furthermore, it eliminates the need for mating machining, significantly reducing processing and maintenance costs. Attached Figure Description

[0019] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0020] Figure 1 is a schematic diagram of the overall structure of the rotor deceleration device provided in the embodiment of this application;

[0021] Figure 2 is a schematic diagram of the internal structure of the rotor deceleration device provided in the embodiment of this application.

[0022] The labels for the attached figures are as follows:

[0023] 1. Rotor assembly; 11. Rotor shaft; 111. First connecting seat; 112. Second connecting seat; 2. Power input assembly; 21. First cylindrical gear; 22. Power input shaft; 23. Input bearing; 24. Input flange; 3. Tail drive assembly; 31. Second cylindrical gear; 32. Tail drive output shaft; 33. Output bearing; 34. Output flange; 4. Reduction assembly; 41. First non-orthogonal gear; 411. Second gear ring; 412. Second transmission ring; 42. Second non-orthogonal gear; 421. First gear ring; 422. First transmission ring; 423. Connecting arm; 5. Transmission housing; 51. Upper transmission housing; 52. Lower transmission housing; 53. Top rotor bearing; 54. Bottom rotor bearing; 6. Shaft upper housing; 7. Shaft lower housing; 8. Shaft bearing. Embodiments of the present invention

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

[0025] This application discloses a rotor speed reduction device, as shown in Figures 1 and 2, including a rotor assembly 1, a power input assembly 2, a tail drive assembly 3, and a speed reduction assembly 4. The rotor assembly 1 includes a rotor shaft 11. The speed reduction assembly 4 includes a first non-orthogonal gear 41 and a second non-orthogonal gear 42, sequentially arranged from top to bottom on the rotor shaft 11. The tooth diameter of the first non-orthogonal gear 41 is smaller than the tooth diameter of the second non-orthogonal gear 42. The power input assembly 2 includes a first cylindrical gear 21, which meshes with the second non-orthogonal gear 42. The tail drive assembly 3 includes a second cylindrical gear 31, which meshes with the first non-orthogonal gear 41.

[0026] Through the implementation of the above-described rotor reduction device embodiment, a power input component 2, a tail drive component 3, and a reduction component 4 are arranged on the rotor shaft 11. The input power is transmitted to the second non-orthogonal surface gear 42 via the meshing connection of the first cylindrical gear 21 and the second non-orthogonal surface gear 42. The second non-orthogonal surface gear 42 then drives the rotor shaft 11 to rotate, thereby reducing and reversing the high-speed, low-torque input power into low-speed, high-torque power transmitted to the rotor shaft 11. Furthermore, the meshing connection between the second cylindrical gear 31 and the first non-orthogonal surface gear 41, and the coaxial transmission of the first non-orthogonal surface gear 41 and the second non-orthogonal surface gear 42, allows the first non-orthogonal surface gear 41 to continue transmitting the input power to the second cylindrical gear 31, which then outputs the power to components such as the tail rotor. Since the tail rotor typically doesn't require the same high rotational speed as the main rotor, a first-stage reduction gear (combined with the first cylindrical gear 21 and the second non-orthogonal gear 42) and a second-stage reduction gear (combined with the second cylindrical gear 31 and the first non-orthogonal gear 41) are used. These two reductions allow the tail rotor to achieve greater torque and higher rotational speed. Simultaneously, the smaller tooth diameter of the first non-orthogonal gear 41 allows it to handle lower power output, further reducing the rotational speed of the tail rotor. This enables optimized power distribution between the main rotor shaft 11 and the tail rotor, effectively improving the drive efficiency of both components.

[0027] As described above, this embodiment applies non-orthogonal surface gears to the main reduction system of a helicopter. Utilizing the adjustable transmission angle of these gears, they can be flexibly arranged to meet the design requirements of any forward tilt angle of the rotor shaft 11. Employing a transmission method combining cylindrical and surface gears, the maximum transmission ratio can reach 20, achieving a higher overall speed ratio for the entire aircraft. This ensures stable transmission ratios in the rotor reduction device of this embodiment, effectively improving power density. Furthermore, since the non-orthogonal surface gears and cylindrical gears can be machined separately and used interchangeably, damage to the cylindrical gears only requires individual replacement, eliminating the need for paired replacements, resulting in low repair costs and short cycles. Moreover, the meshing of the non-orthogonal surface gears and cylindrical gears results in a high degree of tooth surface overlap, smooth operation, and significantly reduced gear contact stress and bending stress. Additionally, the higher axial degree of freedom of the cylindrical gears greatly reduces the difficulty of gear installation and adjustment.

[0028] Furthermore, the rotor reduction gear also includes a transmission housing 5 mounted on the rotor shaft 11, and the transmission housing 5 rotates relative to the rotor shaft 11. The interior of the transmission housing 5 forms a closed accommodating chamber, the reduction assembly 4 is located in the accommodating chamber, and the power input assembly 2 and the tail drive assembly 3 are both mounted on the transmission housing 5.

[0029] Through the implementation of the above-described rotor reduction device embodiment, the transmission housing 5 is used to position and protect the reduction assembly 4, the power input assembly 2, and the tail drive assembly 3, ensuring smooth transmission between them and reducing the impact of external factors on the transmission reduction. Furthermore, the transmission housing 5 rotates relative to the rotor shaft 11 to fix the transmission housing 5, enabling the rotor shaft 11 to rotate stably after being driven by the reduction assembly 4.

[0030] Furthermore, the transmission housing 5 includes an upper transmission housing 51 and a lower transmission housing 52 connected to the upper transmission housing 51. A first assembly channel communicating with the receiving chamber is provided between the upper transmission housing 51 and the lower transmission housing 52. The power input assembly 2 also includes a power input shaft 22 disposed in the first assembly channel and an input bearing 23 disposed on the power input shaft 22. The power input shaft 22 is rotatably connected to the upper transmission housing 51 and the lower transmission housing 52 respectively through the input bearing 23, and a first cylindrical gear 21 is disposed on the inner end of the power input shaft 22.

[0031] Through the implementation of the above-described rotor reduction gear embodiment, the transmission housing 5 is divided into an upper transmission housing 51 and a lower transmission housing 52, which facilitates the disassembly and assembly of the reduction assembly 4, the power input assembly 2, and the tail drive assembly 3, and facilitates the maintenance and replacement of related components. The power input shaft 22 directly connects to the output shaft of the engine or other drive mechanism, allowing the power input shaft 22 to adapt to different types of input power. The input bearing 23 on the power input shaft 22 ensures smooth rotation after receiving input power, avoiding wear caused by contact with the upper and lower transmission housings 51 and 52, and also reducing vibration and noise during transmission. By setting the first cylindrical gear 21 on the inner end of the power input shaft 22, the power input shaft 22 transmits the input power to the second non-orthogonal gear 42 through the first cylindrical gear 21.

[0032] Furthermore, the outer end of the power input shaft 22 extends out of the transmission housing 5 along the first assembly channel, and an input flange 24 is provided on the outer end of the power input shaft 22.

[0033] Through the implementation of the above-described rotor reduction gear embodiment, the input flange 24 allows the power input shaft 22 to be more easily connected to or disconnected from external components, such as the engine output shaft, facilitating installation, disassembly, and maintenance. The input flange 24 provides a robust connection point capable of withstanding high torque and dynamic loads, enhancing the structural strength of the entire transmission system and adapting to different engine output shaft specifications, thus improving the system's versatility and flexibility.

[0034] Furthermore, the upper transmission housing 51 is provided with a second assembly channel communicating with the accommodating cavity. The tail transmission assembly 3 also includes a tail transmission output shaft 32 disposed in the second assembly channel, and an output bearing 33 disposed on the tail transmission output shaft 32. The tail transmission output shaft 32 is rotatably connected to the upper transmission housing 51 via the output bearing 33, and the second cylindrical gear 31 is disposed on the inner end of the tail transmission output shaft 32.

[0035] Through the implementation of the above-described rotor reduction gear embodiment, the tail rotor output shaft 32 is directly connected to the tail rotor section. By setting the second cylindrical gear 31 on the inner end of the tail rotor output shaft 32, the tail rotor output shaft 32 transmits power to the tail rotor section through the meshing transmission of the second cylindrical gear 31 and the first non-orthogonal surface gear 41. Furthermore, the output bearing 33 installed on the tail rotor output shaft 32 ensures smooth rotation after receiving power transmission, avoids wear caused by contact with the upper transmission housing 51, and reduces vibration and noise during transmission.

[0036] Furthermore, the outer end of the tail transmission output shaft 32 extends out of the upper transmission half box 51 along the second assembly channel, and an output flange 34 is provided on the outer end of the tail transmission output shaft 32.

[0037] Through the implementation of the above-described rotor reduction gear embodiment, the output flange 34 allows for easier connection or disconnection of the tail rotor output shaft 32 from the tail rotor section, facilitating installation, disassembly, and maintenance. Furthermore, the output flange 34 provides a robust connection point capable of withstanding high torque and dynamic loads, thereby enhancing the structural strength of the entire transmission system.

[0038] Furthermore, the top of the upper transmission half-box 51 is provided with a top guide cylinder that mates with the rotor shaft 11, and the bottom of the lower transmission half-box 52 is provided with a bottom guide cylinder that mates with the rotor shaft 11. The rotor assembly 1 also includes a top rotor shaft 11 bearing and a bottom rotor shaft 11 bearing disposed on the rotor shaft 11. The rotor shaft 11 is rotatably connected to the top guide cylinder through the top rotor shaft 11 bearing, and the rotor shaft 11 is rotatably connected to the bottom guide cylinder through the bottom rotor shaft 11 bearing.

[0039] Through the implementation of the above-described rotor speed reduction device embodiment, the top and bottom guide cylinders provide precise guidance for the installation of the rotor shaft 11. Furthermore, the top and bottom rotor shaft bearings on the rotor shaft 11, along with the cooperation of the guide cylinders and bearings, control the movement trajectory of the rotor shaft 11, preventing deviation during rotation, ensuring smooth and accurate rotor rotation, and avoiding wear caused by axial or radial movement of the rotor shaft 11.

[0040] Furthermore, the second non-orthogonal gear 42 includes a first gear ring 421, a first transmission ring 422 located below the first gear ring 421, and a connecting arm 423 connecting the first gear ring 421 and the first transmission ring 422. Multiple first teeth are arranged circumferentially on the top surface of the first gear ring 421, and these first teeth are non-orthogonal to the central axis of the first gear ring 421 in the horizontal direction. The inner diameter of the first transmission ring 422 is smaller than the inner diameter of the first gear ring 421. A first connecting seat 111 is provided on the shaft wall of the rotor shaft 11, and the first connecting seat 111 is connected to the top surface of the first transmission ring 422. Multiple connecting arms 423 are arranged circumferentially along the first transmission ring 422.

[0041] Through the implementation of the above-described rotor reduction device embodiment, since the first cylindrical gear 21 and the second non-orthogonal surface gear 42 mesh to form a first-stage reduction, the input power is transmitted to the second non-orthogonal surface gear 42, which in turn drives the rotor shaft 11 to rotate and continue transmitting power upward. Therefore, the power transmission direction of the entire rotor reduction device is from bottom to top. The top surface of the first transmission ring 422 is connected to the first connecting seat 111 on the rotor shaft 11 to ensure that the power can be effectively transmitted from bottom to top to the rotor shaft 11, thereby effectively improving the transmission efficiency. The structure of the second non-orthogonal gear 42 allows the first cylindrical gear 21 to transmit the input power sequentially along the first gear ring 421, connecting arm 423, and first transmission ring 422 to the rotor shaft 11. Since the inner diameter of the first transmission ring 422 is smaller than that of the first gear ring 421, the rotational speed transmitted to the rotor shaft 11 can be further reduced, thereby optimizing the transmission efficiency of the second non-orthogonal gear 42. This ensures that the second non-orthogonal gear 42 can reduce and reverse the high-speed, low-torque input power into low-speed, high-torque power transmitted to the rotor shaft 11. The multiple connecting arms 423 provide a stable connection and transmission structure between the first gear ring 421 and the first transmission ring 422.

[0042] Furthermore, the first non-orthogonal gear 41 includes a second gear ring 411 and a second transmission ring 412 located below the second gear ring 411. The inner diameter of the second transmission ring 412 is smaller than the inner diameter of the second gear ring 411, and the second gear ring 411 is disposed on the top surface of the second transmission ring 412. Multiple second gear teeth are arranged circumferentially on the top surface of the second gear ring 411, and the second gear teeth are non-orthogonal to the central axis of the second gear ring 411 in the horizontal direction. A second connecting seat 112 is disposed on the shaft wall of the rotor shaft 11 above the first connecting seat 111, and the second connecting seat 112 is connected to the bottom surface of the second transmission ring 412.

[0043] Through the implementation of the above-described rotor reduction device embodiment, the bottom surface of the second transmission ring 412 is connected to the second connecting seat 112 on the rotor shaft 11 to ensure that power can be effectively transmitted from bottom to top to the second cylindrical gear 31, thereby effectively improving transmission efficiency. Compared to the structural difference between the first non-orthogonal surface gear 41 and the second non-orthogonal surface gear 42, since the first non-orthogonal surface gear 41 directly transmits the input power to the second cylindrical gear 31, and the second cylindrical gear 31 outputs it to components such as the tail rotor, the second gear ring 411 of the first non-orthogonal surface gear 41 is directly integrally formed with the second transmission ring 412 to ensure transmission efficiency.

[0044] Preferably, the rotor assembly 1 further includes an upper shaft housing 6 and a lower shaft housing 7 sequentially sleeved on the rotor shaft 11 from top to bottom. The upper shaft housing 6 is connected to the lower shaft housing 7, and the lower shaft housing 7 is connected to the top guide cylinder at the top of the upper transmission housing 51. A shaft bearing 8 is also provided on the rotor shaft 11 so that the rotor shaft 11 is rotatably connected to the upper shaft housing 6 and the lower shaft housing 7 respectively through the shaft bearing 8.

[0045] This application also discloses a helicopter that employs the aforementioned rotor speed reduction device. The helicopter includes a fuselage and a rotor speed reduction device mounted on the fuselage.

[0046] By implementing the helicopter described above, the rotor speed reduction device can effectively improve the helicopter's flight efficiency, enabling the helicopter in the application embodiment to obtain higher lift at the same power.

[0047] It should be understood that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims.

Claims

1. A rotor speed reduction device, characterized in that: The rotor reduction device includes a rotor assembly, a power input assembly, a tail drive assembly, and a reduction assembly. The rotor assembly includes a rotor shaft. The reduction assembly includes a first non-orthogonal surface gear and a second non-orthogonal surface gear arranged sequentially from top to bottom on the rotor shaft. The tooth surface diameter of the first non-orthogonal surface gear is smaller than that of the second non-orthogonal surface gear. The power input assembly includes a first cylindrical gear that meshes with the second non-orthogonal surface gear. The tail drive assembly includes a second cylindrical gear that meshes with the first non-orthogonal surface gear.

2. The rotor speed reduction device according to claim 1, characterized in that: The rotor reduction gear also includes a transmission housing mounted on the rotor shaft, and the transmission housing rotates relative to the rotor shaft. The interior of the transmission housing forms a closed accommodating chamber, the reduction assembly is located in the accommodating chamber, and the power input assembly and the tail drive assembly are both mounted on the transmission housing.

3. The rotor speed reduction device according to claim 2, characterized in that: The transmission housing includes an upper transmission housing and a lower transmission housing connected to the upper transmission housing. A first assembly channel communicating with the accommodating cavity is provided between the upper transmission housing and the lower transmission housing. The power input assembly also includes a power input shaft disposed in the first assembly channel and an input bearing disposed on the power input shaft. The power input shaft is rotatably connected to the upper transmission housing and the lower transmission housing respectively through the input bearing. The first cylindrical gear is disposed on the inner end of the power input shaft.

4. The rotor speed reduction device according to claim 3, characterized in that: The outer end of the power input shaft extends out of the transmission housing along the first assembly channel, and an input flange is provided on the outer end of the power input shaft.

5. The rotor speed reduction device according to claim 3, characterized in that: The upper half of the transmission box is provided with a second assembly channel communicating with the accommodating cavity. The tail transmission assembly also includes a tail transmission output shaft provided in the second assembly channel and an output bearing provided on the tail transmission output shaft. The tail transmission output shaft is rotatably connected to the upper half of the transmission box through the output bearing. The second cylindrical gear is provided on the inner end of the tail transmission output shaft.

6. The rotor speed reduction device according to claim 5, characterized in that: The outer end of the tail transmission output shaft extends out of the upper half of the transmission box along the second assembly channel, and an output flange is provided on the outer end of the tail transmission output shaft.

7. The rotor speed reduction device according to claim 3, characterized in that: The upper half of the transmission box is provided with a top guide cylinder that cooperates with the rotor shaft, and the lower half of the transmission box is provided with a bottom guide cylinder that cooperates with the rotor shaft. The rotor assembly also includes a top rotor bearing and a bottom rotor bearing provided on the rotor shaft. The rotor shaft is rotatably connected to the top guide cylinder through the top rotor bearing, and the rotor shaft is rotatably connected to the bottom guide cylinder through the bottom rotor bearing.

8. The rotor speed reduction device according to claim 1, characterized in that: The second non-orthogonal gear includes a first gear ring, a first transmission ring located below the first gear ring, and a connecting arm connecting the first gear ring and the first transmission ring. A plurality of first gear teeth are arranged circumferentially on the top surface of the first gear ring, and the first gear teeth are non-orthogonal to the central axis of the first gear ring in the horizontal direction. The inner diameter of the first transmission ring is smaller than the inner diameter of the first gear ring. A first connecting seat is provided on the shaft wall of the rotor shaft. The first connecting seat is connected to the top surface of the first transmission ring. A plurality of connecting arms are provided along the circumference of the first transmission ring.

9. The rotor speed reduction device according to claim 8, characterized in that: The first non-orthogonal gear includes a second gear ring and a second transmission ring located below the second gear ring. The inner diameter of the second transmission ring is smaller than the inner diameter of the second gear ring, and the second gear ring is disposed on the top surface of the second transmission ring. A plurality of second gear teeth are arranged circumferentially on the top surface of the second gear ring, and the second gear teeth are non-orthogonal to the central axis of the second gear ring in the horizontal direction. A second connecting seat is provided on the shaft wall of the rotor shaft above the first connecting seat, and the second connecting seat is connected to the bottom surface of the second transmission ring.

10. A helicopter, characterized in that, The rotor deceleration device according to any one of claims 1-9 is used: the helicopter includes a fuselage and the rotor deceleration device disposed on the fuselage.

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