Rotor wing speed reducer and helicopter

Abstract

The invention relates to the technical field of aircrafts, in particular to a rotor wing speed reducer and a helicopter. The rotor wing speed reduction device comprises a rotor wing assembly, a power input assembly, a tail transmission assembly and a speed reduction assembly, the rotor wing assembly comprises a rotor wing shaft, the speed reduction assembly comprises a first non-orthogonal face gear and a second non-orthogonal face gear which are arranged on the rotor wing shaft, and the tooth surface diameter of the first non-orthogonal face gear is smaller than that of the second non-orthogonal face gear; the power input assembly comprises a first cylindrical gear connected with the second non-orthogonal face gear in a meshed mode, and the tail transmission assembly comprises a second cylindrical gear connected with the first non-orthogonal face gear in a meshed mode. The design requirement of any front inclination angle of the rotor shaft can be met, the transmission mode of the cylindrical gear and the face gear is adopted, the higher speed ratio of the whole machine is achieved, the transmission ratio is stable, and the power density is effectively improved. And pairing processing is not needed, so that the processing and maintenance cost is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, in particular to a rotor speed reduction device and a helicopter. Background Art

[0002] At present, helicopters are one of the main forces in the field of general aviation. They usually have unique vertical take-off and landing capabilities. They can hover in the air, fly forward, backward, left, and right in any direction, and can take off and land in unprepared places or rooftop platforms. This is irreplaceable by fixed-wing aircraft and other means of transportation. Among them, the helicopter main reducer is one of the main transmission components on the helicopter. It reduces the high-speed, low-torque engine power and converts it into low-speed, high-torque power to transmit to the rotor shaft, and transmits the power to the tail rotor according to the speed and torque requirements. In addition to transmitting power, the helicopter main reducer also directly bears all the forces and torques generated by the rotor and transmits them to the fuselage, playing the role of a central force-bearing component.

[0003] At present, the main reducer of helicopters has high power and transmission ratio. When the rotor shaft is at a forward tilt angle, the input shaft is parallel to the tail shaft, but not orthogonal to the rotor shaft. Therefore, a transmission form of 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, and its transmission ratio is relatively small. As a result, in order to achieve the purpose of a large speed ratio of the main reducer, it is necessary to connect a multi-stage planetary gear system in series after the non-orthogonal bevel gear, and its power density will be limited; (2) Bevel gears are usually manufactured and used in pairs, and the interchangeability of parts is poor. They need to be replaced in pairs, which has high maintenance costs, great difficulty, and long cycles; (3) Due to processing errors and installation errors, the cone top angle cannot overlap, resulting in an unstable transmission ratio, unstable transmission, and prone to fatigue problems; (4) When multiple pairs of bevel gear pairs are meshed at the same time, because the smaller bevel gears need to withstand a large axial force, the axial force on the shaft is large, 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 the present invention is to provide a rotor reduction device and a helicopter to solve the above-mentioned problem that the main reducer of the helicopter in the prior art adopts a transmission form of non-orthogonal bevel gears and planetary gears.

[0005] The present invention discloses a rotor reduction device, including a rotor assembly, a power input assembly, a tail transmission assembly and a reduction assembly, wherein the rotor assembly includes a rotor shaft, the reduction assembly includes a first non-orthogonal face gear and a second non-orthogonal face gear arranged on the rotor shaft from top to bottom, the tooth surface diameter of the first non-orthogonal face gear is smaller than the tooth surface diameter of the second non-orthogonal face gear, the power input assembly includes a first cylindrical gear, the first cylindrical gear is meshed with the second non-orthogonal face gear, and the tail transmission assembly includes a second cylindrical gear, the second cylindrical gear is meshed with the first non-orthogonal face gear.

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

[0007] Optionally, the transmission casing includes a transmission upper casing, and a transmission lower casing connected to the transmission upper casing, a first assembly channel connected to the accommodating chamber is provided between the transmission upper casing and the transmission lower casing, the power input assembly also includes a power input shaft arranged in the first assembly channel, and an input bearing arranged on the power input shaft, the power input shaft is rotatably connected to the transmission upper casing and the transmission lower casing respectively through the input bearing, and the first cylindrical gear is arranged on the inner end of the power input shaft.

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

[0009] Optionally, a second assembly channel connected to the accommodating chamber is provided on the transmission upper half box, and the tail transmission assembly also includes a tail transmission output shaft arranged in the second assembly channel, and an output bearing arranged on the tail transmission output shaft, the tail transmission output shaft is rotatably connected to the transmission upper half box through the output bearing, and the second cylindrical gear is arranged 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 transmission upper half box along the second assembly channel, and an output flange is provided on the outer end of the tail transmission output shaft.

[0011] Optionally, a top guide cylinder cooperating with the rotor shaft is provided at the top of the transmission upper half box, and a bottom guide cylinder cooperating with the rotor shaft is provided at the bottom of the transmission lower half box, and the rotor assembly also includes a top rotor bearing and a bottom rotor bearing provided on the rotor shaft, and the rotor shaft is rotatably connected to the top guide cylinder via the top rotor bearing, and the rotor shaft is rotatably connected to the bottom guide cylinder via the bottom rotor bearing.

[0012] Optionally, the second non-orthogonal face 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 in a non-orthogonal structure with 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 arranged 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 arranged along the circumference of the first transmission ring.

[0013] Optionally, the first non-orthogonal face 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 arranged 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 in a non-orthogonal structure with the central axis of the second gear ring in the horizontal direction; A second connection seat is arranged on the shaft wall of the rotor shaft above the first connection seat, and the second connection seat is connected to the bottom surface of the second transmission ring.

[0014] The present invention also discloses a helicopter, which adopts the above-mentioned rotor reduction device. The helicopter comprises an airframe and the rotor reduction device arranged on the airframe.

[0015] Compared with the prior art, the rotor speed reduction device and the helicopter provided by the embodiments of the present invention have the following beneficial effects: By arranging a power input assembly, a tail transmission assembly and a reduction assembly on the rotor shaft, the input power is transmitted to the second non-orthogonal face gear by meshing the first cylindrical gear with the second non-orthogonal face gear, and the second non-orthogonal face gear drives the rotor shaft to rotate, so as to reduce the input power with high speed and small torque, and convert it into low speed and large torque power to be transmitted to the rotor shaft. And by meshing the second cylindrical gear with the first non-orthogonal face gear, and the coaxial transmission of the first non-orthogonal face gear and the second non-orthogonal face gear, the input power is further transmitted to the second cylindrical gear, and the second cylindrical gear outputs it to the tail rotor and other components. Since the tooth surface diameter of the first non-orthogonal face gear is small, the input speed can be further reduced, and the tail rotor part has a larger torque and a lower speed through two reductions, thereby allowing the power requirements of the rotor shaft and the tail rotor to be optimally distributed. Therefore, the non-orthogonal face gear is applied to the main reducer of the helicopter. Its transmission angle is adjustable, which can meet the design requirements of any forward tilt angle of the rotor shaft. The transmission method of cylindrical gears and face gears is adopted to achieve a larger speed ratio of the whole machine. Its transmission ratio is stable and the power density is effectively improved. There is no need for paired processing, which greatly reduces the processing and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which: Figure 1 A schematic diagram of the overall structure of a rotor speed reduction device provided in an embodiment of the present invention; Figure 2 A schematic diagram of the internal structure of a rotor reduction gear provided in an embodiment of the present invention.

[0017] The reference numerals in the figures are: 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 transmission assembly; 31. Second cylindrical gear; 32. Tail transmission output shaft; 33. Output bearing; 34. Output flange; 4. Speed ​​reduction assembly; 41. First non-orthogonal face gear; 411. Second gear ring; 412. Second transmission ring; 42. Second non-orthogonal face gear; 421. First gear ring; 422. First transmission ring; 423. Connecting arm; 5. Transmission casing; 51. Transmission upper casing; 52. Transmission lower casing; 53. Top rotor bearing; 54. Bottom rotor bearing; 6. Shaft upper casing; 7. Shaft lower casing; 8. Shaft bearing. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0019] The present invention discloses a rotor speed reduction device, such as Figure 1 and Figure 2 As shown, it includes a rotor assembly 1, a power input assembly 2, a tail transmission assembly 3 and a reduction assembly 4. The rotor assembly 1 includes a rotor shaft 11, and the reduction assembly 4 includes a first non-orthogonal face gear 41 and a second non-orthogonal face gear 42 arranged on the rotor shaft 11 from top to bottom, and the tooth surface diameter of the first non-orthogonal face gear 41 is smaller than the tooth surface diameter of the second non-orthogonal face gear 42. The power input assembly 2 includes a first cylindrical gear 21, and the first cylindrical gear 21 is meshed and connected with the second non-orthogonal face gear 42. The tail transmission assembly 3 includes a second cylindrical gear 31, and the second cylindrical gear 31 is meshed and connected with the first non-orthogonal face gear 41.

[0020] Through the implementation of the above rotor reduction device embodiment, a power input assembly 2, a tail transmission assembly 3 and a reduction assembly 4 are arranged on the rotor shaft 11, and the first cylindrical gear 21 is meshed and connected with the second non-orthogonal face gear 42, so that the input power can be transmitted to the second non-orthogonal face gear 42, and the second non-orthogonal face gear 42 drives the rotor shaft 11 to rotate, so as to reduce the input power of high speed and small torque, and convert it into low speed and large torque power to be transmitted to the rotor shaft 11. And by meshing and connecting the second cylindrical gear 31 with the first non-orthogonal face gear 41, and the coaxial transmission of the first non-orthogonal face gear 41 and the second non-orthogonal face gear 42, the first non-orthogonal face gear 41 continues to transmit the input power to the second cylindrical gear 31, and the second cylindrical gear 31 outputs it to the tail rotor and other components. Since the tail rotor usually does not need as high a rotation speed as the rotor, the first cylindrical gear 21 and the second non-orthogonal face gear 42 form a first-stage reduction, and the second cylindrical gear 31 and the first non-orthogonal face gear 41 form a second-stage reduction. The tail rotor part has a larger torque and a higher rotation speed through two reductions. At the same time, the first non-orthogonal face gear 41 has a smaller tooth surface diameter and can bear a smaller power output, so that the rotation speed of the output tail rotor part can be further reduced, thereby allowing the power requirements of the rotor shaft 11 and the tail rotor to be optimally distributed, effectively improving the driving efficiency of the rotor shaft 11 and the tail rotor part.

[0021] As described above, the embodiment of the present invention applies non-orthogonal face gears to the main reduction system of the helicopter. The transmission angle of the non-orthogonal face gears is adjustable and can be flexibly arranged to meet the design requirements of any forward inclination angle of the rotor shaft 11. The transmission method of cylindrical gears and face gears is adopted, and its maximum transmission ratio can reach 20, so as to achieve a larger speed ratio of the whole machine, so that the transmission ratio of the rotor reduction device of the embodiment of the present invention is stable, and the power density is effectively improved. At the same time, since the non-orthogonal face gears and cylindrical gears can be processed separately, they can be used together. Therefore, if the cylindrical gears are damaged, only a single replacement is required, and there is no need to replace them in pairs, and the rework cost is low and the cycle is short. Furthermore, the meshing of the non-orthogonal face gears and the cylindrical gears has a large tooth surface overlap, stable operation, and significantly reduces the gear contact stress and bending stress. In addition, the axial degree of freedom of the cylindrical gears is relatively high, which can greatly reduce the difficulty of gear installation and adjustment.

[0022] Furthermore, the rotor reduction device further includes a transmission case 5 disposed on the rotor shaft 11, and the transmission case 5 rotates relative to the rotor shaft 11. The interior of the transmission case 5 forms a closed accommodation chamber, the reduction assembly 4 is located in the accommodation chamber, and the power input assembly 2 and the tail transmission assembly 3 are both disposed on the transmission case 5.

[0023] Through the implementation of the above rotor reduction device embodiment, the transmission case 5 is used to position and protect the reduction assembly 4, the power input assembly 2 and the tail transmission assembly 3, so as to ensure smooth transmission between the reduction assembly 4, the power input assembly 2 and the tail transmission assembly 3, and reduce the influence of external factors on the transmission reduction. In addition, the transmission case 5 is used to rotate relative to the rotor shaft 11, so that the transmission case 5 is fixed, so that the rotor shaft 11 can rotate stably after being driven by the reduction assembly 4.

[0024] Further, the transmission casing 5 includes a transmission upper casing 51 and a transmission lower casing 52 connected to the transmission upper casing 51. A first assembly channel communicating with the accommodating chamber is provided between the transmission upper casing 51 and the transmission lower casing 52, and the power input assembly 2 also includes a power input shaft 22 provided in the first assembly channel, and an input bearing 23 provided on the power input shaft 22. The power input shaft 22 is rotationally connected to the transmission upper casing 51 and the transmission lower casing 52 respectively through the input bearing 23, and the first cylindrical gear 21 is provided on the inner side end of the power input shaft 22.

[0025] Through the implementation of the above rotor speed reduction device embodiment, the transmission casing 5 is divided into a transmission upper casing 51 and a transmission lower casing 52, so as to facilitate the disassembly and assembly of the speed reduction assembly 4, the power input assembly 2 and the tail transmission assembly 3, and facilitate the maintenance and replacement of related components. The power input shaft 22 is directly connected to the output shaft of the driving mechanism such as the engine, allowing the power input shaft 22 to adapt to different types of input power, and using the input bearing 23 set on the power input shaft 22, it is ensured that the power input shaft 22 rotates smoothly after receiving the input power, and avoids the wear caused by contact with the transmission upper casing 51 and the transmission lower casing 52, and can also reduce the vibration and noise during the transmission process. By setting the first cylindrical gear 21 on the inner side end of the power input shaft 22, the power input shaft 22 can transmit the input power to the second non-orthogonal face gear 42 through the first cylindrical gear 21.

[0026] Furthermore, the outer end of the power input shaft 22 extends out of the transmission casing 5 along the first assembly channel, and an input flange 24 is provided on the outer end of the power input shaft 22 .

[0027] Through the implementation of the above rotor reduction device embodiment, the power input shaft 22 can be more easily connected or disconnected with external components, such as the engine output shaft, by using the input flange 24, so as to facilitate installation, disassembly and maintenance. The input flange 24 provides a solid connection point that can withstand high torque and dynamic loads, can enhance the structural strength of the entire transmission system, and can adapt to engine output shafts of different specifications, thereby improving the versatility and flexibility of the system.

[0028] Furthermore, a second assembly channel communicating with the accommodating chamber is provided on the transmission upper half case 51. 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 transmission upper half case 51 through the output bearing 33, and the second cylindrical gear 31 is disposed on the inner side end of the tail transmission output shaft 32.

[0029] Through the implementation of the above rotor speed reduction device embodiment, the tail transmission output shaft 32 is directly connected to the tail rotor part, and the second cylindrical gear 31 is set on the inner side end of the tail transmission output shaft 32, so that the tail transmission output shaft 32 can output power to the tail rotor part through the meshing transmission of the second cylindrical gear 31 and the first non-orthogonal face gear 41. The output bearing 33 set on the tail transmission output shaft 32 is used to ensure that the tail transmission output shaft 32 rotates smoothly after receiving power transmission, and avoids wear caused by contact with the transmission upper half box 51, and can also reduce vibration and noise during the transmission process.

[0030] Furthermore, the outer end of the tail transmission output shaft 32 extends out of the transmission upper 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 .

[0031] By implementing the above rotor reduction device embodiment, the output flange 34 is used to make it easier for the tail transmission output shaft 32 to be connected or disconnected from the tail rotor part, so as to facilitate installation, disassembly and maintenance. The output flange 34 provides a strong connection point that can withstand high torque and dynamic load to enhance the structural strength of the entire transmission system.

[0032] Furthermore, a top guide cylinder matched with the rotor shaft 11 is provided at the top of the transmission upper half box 51, and a bottom guide cylinder matched with the rotor shaft 11 is provided at the bottom of the transmission lower half box 52. The rotor assembly 1 also includes a top rotor shaft 11 bearing and a bottom rotor shaft 11 bearing provided 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.

[0033] By implementing the above rotor speed reduction device embodiment, the top guide cylinder and the bottom guide cylinder are arranged to provide accurate guidance for the installation of the rotor shaft 11. And by using the top rotor shaft 11 bearing and the bottom rotor shaft 11 bearing arranged on the rotor shaft 11, through the cooperation of the guide cylinder and the bearing, the motion trajectory of the rotor shaft 11 is controlled to prevent the rotor shaft 11 from deflecting during the rotation process, ensure the smooth and accurate rotation of the rotor, and avoid the wear of the rotor shaft 11 caused by axial or radial movement.

[0034] Furthermore, the second non-orthogonal face 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. A plurality of first gear teeth are arranged circumferentially on the top surface of the first gear ring 421, and the first gear teeth are in a non-orthogonal structure with 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, and 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. Among them, a plurality of connecting arms 423 are provided along the circumference of the first transmission ring 422.

[0035] Through the implementation of the above-mentioned rotor reduction device embodiment, the first cylindrical gear 21 is meshed with the second non-orthogonal face gear 42 to form a first-stage reduction, so as to transmit the input power to the second non-orthogonal face gear 42, and the second non-orthogonal face gear 42 drives the rotor shaft 11 to rotate and continue to transmit power upward. Therefore, the power transmission direction of the entire rotor reduction device is from bottom to top. The first connecting seat 111 on the rotor shaft 11 is connected to the top surface of the first transmission ring 422 to ensure that the power can be effectively transmitted from bottom to top to the rotor shaft 11, effectively improving the transmission efficiency. And by utilizing the structure of the second non-orthogonal face gear 42, the first cylindrical gear 21 transmits the input power to the rotor shaft 11 in sequence along the first gear ring 421, the connecting arm 423 and the first transmission ring 422. Since the inner diameter of the first transmission ring 422 is smaller than the inner diameter of the first gear ring 421, the rotation speed transmitted to the rotor shaft 11 can be further reduced, thereby optimizing the transmission efficiency of the second non-orthogonal face gear 42, so as to meet the second non-orthogonal face gear 42 to decelerate the input power of high speed and small torque, and convert it into low speed and large torque power to transmit to the rotor shaft 11. Among them, by utilizing the setting of multiple connecting arms 423, a stable connection and transmission structure is provided between the first gear ring 421 and the first transmission ring 422.

[0036] Furthermore, the first non-orthogonal face 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 arranged on the top surface of the second transmission ring 412. A plurality of second gear teeth are arranged circumferentially on the top surface of the second gear ring 411, and the second gear teeth are in a non-orthogonal structure with the central axis of the second gear ring 411 in the horizontal direction. A second connecting seat 112 is arranged 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.

[0037] Through the implementation of the above rotor reduction device embodiment, the second connection seat 112 on the rotor shaft 11 is used to connect the bottom surface of the second transmission ring 412 to ensure that the power can be effectively transmitted from bottom to top to the second cylindrical gear 31, effectively improving the transmission efficiency. Compared with the difference in structure with the second non-orthogonal face gear 42, since the first non-orthogonal face gear 41 directly transmits the input power to the second cylindrical gear 31, and the second cylindrical gear 31 outputs it to the tail rotor and other components. Therefore, the second gear ring 411 of the first non-orthogonal face gear 41 is directly integrated with the second transmission ring 412 to ensure transmission efficiency.

[0038] Preferably, the rotor assembly 1 further comprises an upper shaft casing 6 and a lower shaft casing 7 which are sequentially sleeved on the rotor shaft 11 from top to bottom, the upper shaft casing 6 is connected to the lower shaft casing 7, and the lower shaft casing 7 is connected to the top guide cylinder at the top of the transmission upper half casing 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 casing 6 and the lower shaft casing 7 through the shaft bearing 8.

[0039] The invention also discloses a helicopter, which adopts the above-mentioned rotor reduction device. The helicopter comprises a body and the rotor reduction device arranged on the body.

[0040] Through the implementation of the above-mentioned helicopter, the flight efficiency of the helicopter can be effectively improved by using the rotor reduction device, so that the helicopter of the embodiment of the invention can obtain higher lift under the same power.

[0041] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

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

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

3. The rotor speed reduction device according to claim 2, characterized in that: The transmission casing includes a transmission upper casing and a transmission lower casing connected to the transmission upper casing, a first assembly channel connected to the accommodating chamber is provided between the transmission upper casing and the transmission lower casing, the power input assembly also includes a power input shaft arranged in the first assembly channel, and an input bearing arranged on the power input shaft, the power input shaft is rotatably connected to the transmission upper casing and the transmission lower casing respectively through the input bearing, and the first cylindrical gear is arranged 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 casing along the first assembly channel, and an input flange is arranged on the outer end of the power input shaft.

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

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

8. The rotor speed reduction device according to claim 1, characterized in that: The second non-orthogonal face 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 in a non-orthogonal structure with 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 arranged 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 arranged 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 face 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 arranged 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 in a non-orthogonal structure with the central axis of the second gear ring in the horizontal direction; A second connection seat is arranged on the shaft wall of the rotor shaft above the first connection seat, and the second connection seat is connected to the bottom surface of the second transmission ring.

10. A helicopter, characterized in that: The rotor reduction device according to any one of claims 1 to 9 is adopted: the helicopter comprises an airframe, and the rotor reduction device arranged on the airframe.

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