阅读说明：本技术 一种具有锥齿轮分路的共轴双旋翼直升机传动装置 (Coaxial dual-rotor helicopter transmission device with bevel gear shunt ) 是由 张玉姣 朱如鹏 李苗苗 张栋林 倪德 王永红 于 2020-05-27 设计创作，主要内容包括：一种具有锥齿轮分路的共轴双旋翼直升机传动装置。本发明涉及共轴双旋翼直升机传动系统构型领域。提出了一种具有锥齿轮分路的共轴双旋翼直升机传动装置,对大功率高速传动系统有着非常重要的意义。本发明的技术方案为：包括输出单元和至少一个功率输入分流单元；所述输出单元包括内旋翼轴27和外旋翼轴28；所述功率输入分流单元包括输入轴1、第一齿轮轴4、第二齿轮轴9、第三齿轮轴10、第四齿轮轴17和第六齿轮轴19。本发明的传动系统构型,可以在中、重型直升机传动系统、舰船传动系统等领域得到广泛的应用。能有效降低整个传动系统的体积和重量,提高系统的稳定性和可靠性。(A coaxial twin rotor helicopter transmission with bevel gear shunts. The invention relates to the field of coaxial dual-rotor helicopter transmission system configurations. The coaxial dual-rotor helicopter transmission device with the bevel gear shunt has very important significance for a high-power high-speed transmission system. The technical scheme of the invention is as follows: the power input shunt unit comprises an output unit and at least one power input shunt unit; the output unit comprises an inner rotor shaft 27 and an outer rotor shaft 28; the power input splitting unit includes an input shaft 1, a first gear shaft 4, a second gear shaft 9, a third gear shaft 10, a fourth gear shaft 17, and a sixth gear shaft 19. The transmission system configuration of the invention can be widely applied in the fields of medium and heavy helicopter transmission systems, ship transmission systems and the like. The volume and the weight of the whole transmission system can be effectively reduced, and the stability and the reliability of the system are improved.)

1. A coaxial twin rotor helicopter transmission with bevel gear shunts comprising an output unit and at least one power input shunt unit;

the output unit comprises an inner rotor shaft (27) and an outer rotor shaft (28) which are coaxial;

the power input split unit comprises an input shaft (1), a first gear shaft (4), a second gear shaft (9), a third gear shaft (10), a fourth gear shaft (17) and a sixth gear shaft (19); the input shaft (1) is linked with the first gear shaft (4), the first gear shaft (4) is simultaneously linked with the second gear shaft (9) and the third gear shaft (10), the rotation directions of the second gear shaft (9) and the third gear shaft (10) are opposite, the second gear shaft (9), the fourth gear shaft (17) and the inner rotor shaft (27) are sequentially linked, and the third gear shaft (10), the sixth gear shaft (19) and the outer rotor shaft (28) are sequentially linked;

the second gear shaft (9) and the third gear shaft (10) are arranged in parallel to the axial direction of the output unit, and the first gear shaft (4) is arranged perpendicular to the axial direction of the output unit;

a first bevel gear (5) and a second bevel gear (6) are fixedly arranged on the first gear shaft (4), and the first bevel gear (5) and the second bevel gear (6) are arranged oppositely; a third bevel gear (7) meshed with the first bevel gear (5) is fixedly arranged on the second gear shaft (9), and a fourth bevel gear (8) meshed with the second bevel gear (6) is fixedly arranged on the third gear shaft (10);

the third bevel gear (7) and the fourth bevel gear (8) are arranged between the first bevel gear (5) and the second bevel gear (6).

2. A coaxial twin-rotor helicopter transmission with bevel gear shunt according to claim 1 characterized by that the input shaft (1) and first gear shaft (4) are linked by a reduction gear set;

the first gear shaft (4), the second gear shaft (9), the fourth gear shaft (17) and the inner rotor shaft (27) are sequentially linked through the speed reduction gear set;

the first gear shaft (4), the third gear shaft (10), the sixth gear shaft (19) and the outer rotor shaft (28) are sequentially linked through the speed reduction gear set;

the reduction ratio of the first gear shaft (4) to the inner rotor shaft (27) is equal to the reduction ratio of the first gear shaft (4) to the outer rotor shaft (28).

3. The co-axial twin-rotor helicopter transmission with bevel gear shunt according to claim 1 characterized by that one side of the fourth gear shaft (17) is further equipped with a fifth gear shaft (18) parallel to it, the fifth gear shaft (18) is linked with the second gear shaft (9) and the inner rotor shaft (27) simultaneously, the reduction ratio of the second gear shaft (9) to the fourth gear shaft (17) is equal to the reduction ratio of the second gear shaft (9) to the fifth gear shaft (18), and the reduction ratio of the fourth gear shaft (17) to the inner rotor shaft (27) is equal to the reduction ratio of the fifth gear shaft (18) to the inner rotor shaft (27).

4. The co-axial twin-rotor helicopter transmission with bevel gear shunt according to claim 1 characterized in that one side of the sixth gear shaft (19) is further provided with a seventh gear shaft (20) parallel to it, the seventh gear shaft (20) is simultaneously linked with the third gear shaft (10) and the outer rotor shaft (28), the reduction ratio of the third gear shaft (10) to the sixth gear shaft (19) is equal to the reduction ratio of the third gear shaft (10) to the seventh gear shaft (20), and the reduction ratio of the sixth gear shaft (19) to the outer rotor shaft (28) is equal to the reduction ratio of the seventh gear shaft (20) to the outer rotor shaft (28).

5. The co-axial twin-rotor helicopter transmission with bevel gear shunt according to claim 1 characterized by that in the four-stage dead axle reduction structure between the input shaft (1) to the inner rotor shaft (27), the reduction ratio of the fourth gear shaft (17) to the inner rotor shaft (27) is the largest;

in the four-stage dead axle speed reducing structure between the input shaft (1) and the outer rotor shaft (28), the speed reducing ratio of the sixth gear shaft (19) and the outer rotor shaft (28) is the largest.

6. The co-axial twin rotor helicopter transmission with bevel gear shunt of claim 1 wherein the power input shunt unit has 1-3.

7. A co-axial twin rotor helicopter transmission with bevel gear shunt according to claim 3 or 4 wherein the input shaft and first gear shaft are horizontal and the second gear shaft, third gear shaft, fourth gear shaft, fifth gear shaft, sixth gear shaft, seventh gear shaft, inner rotor shaft and outer rotor shaft are vertical.

8. A co-axial twin-rotor helicopter transmission with bevel gear shunt according to claim 3 or 4 characterized by that the input shaft (1) has a first gear (2) fixed to it and the first gear shaft (4) has a second gear (3) fixed to it;

a third gear (11) is fixedly arranged on the second gear shaft (9), a fourth gear (12) is fixedly arranged on the third gear shaft (10), a fifth gear (13) and a ninth gear (21) are fixedly arranged on the fourth gear shaft (17), a sixth gear (14) and a tenth gear (22) are fixedly arranged on the fifth gear shaft (18), a seventh gear (15) and an eleventh gear (23) are fixedly arranged on the sixth gear shaft (19), and an eighth gear (16) and a twelfth gear (24) are fixedly arranged on the seventh gear shaft (20);

a thirteenth gear (25) is fixedly arranged on the inner rotor wing shaft (27), and a fourteenth gear (26) is fixedly arranged on the outer rotor wing shaft (28);

the first gear (2) is meshed with the second gear (3);

the third gear (11) is meshed with a fifth gear (13) and a sixth gear (14) simultaneously, and the ninth gear (21) and the tenth gear (22) are meshed with a thirteenth gear (25) simultaneously;

the fourth gear (12) is meshed with a seventh gear (15) and an eighth gear (16) simultaneously, and the eleventh gear (23) and the twelfth gear (24) are meshed with a fourteenth gear (26) simultaneously.

9. The co-axial twin rotor helicopter transmission of claim 1 where the first, second, third, fourth, fifth, sixth, seventh and eighth gears are spur gears, the first, second, third and fourth bevel gears are spiral bevel gears and the ninth, tenth, eleventh, twelfth, thirteenth and fourteenth gears are bevel or spur gears.

Technical Field

The invention relates to the field of coaxial dual-rotor helicopter transmission system configurations, in particular to a coaxial dual-rotor helicopter transmission device with a bevel gear shunt, which is a transmission configuration of a main reducer of a coaxial dual-rotor helicopter, wherein the transmission configuration utilizes the bevel gear shunt to complete reversing and speed reduction and realize coaxial reversion.

Background

The helicopter transmission system, together with the engine and the rotor system, is called three key moving parts of the helicopter, and is used for transmitting the output power and the output rotating speed of the engine to the rotor, the tail rotor and accessories according to a certain proportion. The transmission system of the coaxial dual-rotor helicopter is more complex than that of a single-rotor helicopter, because one engine of the coaxial dual-rotor helicopter needs to simultaneously drive the upper and lower rotors to rotate in the same speed and in opposite directions so as to achieve self torque balance, the rotating speed precision is strictly controlled, and the complexity of the transmission device is undoubtedly increased.

At present, the typical configuration of a coaxial dual-rotor helicopter transmission system is mainly a closed differential planetary gear train coaxial configuration designed by Russian Moov design office, and is characterized in that no matter the former stages adopt 'parallel operation and then reversing', 'reversing first and then parallel operation', or 'reversing simultaneously and parallel operation', the last stage adopts a closed differential planetary gear train. The configuration is widely applied to a main speed reducer of a Russian Ka series helicopter, such as a helicopter main speed reducer of Ka-28, Ka-50 and the like. But because of the problems of structural strength, efficiency and the like of the planetary gear transmission, the transmission is small; meanwhile, the planet wheel not only has revolution but also has rotation, so the structure is complex, the service working condition of the support bearing is complex, the bearing is easy to damage, and the closed differential planetary gear train has difficult gear matching, complex structure, high requirement on manufacturing precision and difficult manufacturing and installation.

In contrast, the national intellectual property office published a chinese patent invention entitled "a bevel gear-cylindrical gear two-power split coaxial dual-rotor transmission", with application number "201910011019.9", in 2019, 5, 3, month, and year, in which two-way transmission and power split are achieved by simultaneously engaging two bevel gears having the same axis with one input bevel gear; however, in the structural layout of such a transmission, a large space needs to be left in the up-down direction, i.e. the axial direction of the two coaxial power output shafts, so as to facilitate the arrangement of the input bevel gear; therefore, the defects of large volume, complex design layout and the like of the transmission device are brought.

In addition, the transmission device has extremely high requirements on the structural stability of the power input shaft, more supporting points are required to be provided for the power input shaft, the difficulty and the complexity of the design layout are further increased, and the overall volume of the transmission device is difficult to reduce.

Meanwhile, the transmission device is characterized in that one bevel gear is meshed with two bevel gears simultaneously, the upper layer gear and the lower layer gear are both bevel gears (usually vertically mounted at 90 degrees), the structure has very high requirements on the meshing clearance between the teeth, the mounting needs to be repeatedly disassembled and adjusted to achieve the optimal meshing state, a large number of tools and fixture measuring tools need to be used for auxiliary matching, the assembling workload and the assembling difficulty of the gears are increased undoubtedly, the mounting efficiency is reduced, and otherwise the gears can be prematurely damaged due to eccentricity or poor meshing. This places high demands on the manufacture and installation of bevel gears, especially in aeronautical structures, which are difficult to achieve given the high precision manufacturing and installation standards.

Disclosure of Invention

Aiming at the problems, the invention provides a coaxial dual-rotor helicopter transmission device with a bevel gear shunt, wherein four-stage speed reduction adopts a fixed-axis gear train, the technology is mature, and the reliability is high; meanwhile, the transmission device has the advantages of compact structure, convenience in layout, no movement interference and the like on the whole through the improvement of the structure of the transmission device.

The technical scheme of the invention is as follows: the power input shunt unit comprises an output unit and at least one power input shunt unit;

the output unit comprises coaxial inner and outer rotor shafts 27, 28;

the power input split unit comprises an input shaft 1, a first gear shaft 4, a second gear shaft 9, a third gear shaft 10, a fourth gear shaft 17 and a sixth gear shaft 19; the input shaft 1 is linked with the first gear shaft 4, the first gear shaft 4 is simultaneously linked with the second gear shaft 9 and the third gear shaft 10, the rotation directions of the second gear shaft 9 and the third gear shaft 10 are opposite, the second gear shaft 9, the fourth gear shaft 17 and the inner rotor shaft 27 are sequentially linked, and the third gear shaft 10, the sixth gear shaft 19 and the outer rotor shaft 28 are sequentially linked.

The second gear shaft 9 and the third gear shaft 10 are arranged in parallel to the axial direction of the output unit, and the first gear shaft 4 is arranged perpendicular to the axial direction of the output unit;

a first bevel gear 5 and a second bevel gear 6 are fixedly arranged on the first gear shaft 4, and the first bevel gear 5 and the second bevel gear 6 are oppositely arranged; a third bevel gear 7 meshed with the first bevel gear 5 is fixedly arranged on the second gear shaft 9, and a fourth bevel gear 8 meshed with the second bevel gear 6 is fixedly arranged on the third gear shaft 10;

the third bevel gear 7 and the fourth bevel gear 8 are arranged between the first bevel gear 5 and the second bevel gear 6.

Further, the input shaft 1 and the first gear shaft 4 are linked through a reduction gear set;

the first gear shaft 4, the second gear shaft 9, the fourth gear shaft 17 and the inner rotor shaft 27 are linked through a reduction gear set in sequence;

the first gear shaft 4, the third gear shaft 10, the sixth gear shaft 19 and the outer rotor shaft 28 are linked through a reduction gear set in sequence;

the reduction ratio of the first gear shaft 4 to the inner rotor shaft 27 is equal to the reduction ratio of the first gear shaft 4 to the outer rotor shaft 28.

Further, a fifth gear shaft 18 parallel to the fourth gear shaft 17 is further disposed on one side of the fourth gear shaft 17, the fifth gear shaft 18 is simultaneously linked with the second gear shaft 9 and the inner rotor shaft 27, a reduction ratio of the second gear shaft 9 to the fourth gear shaft 17 is equal to a reduction ratio of the second gear shaft 9 to the fifth gear shaft 18, and a reduction ratio of the fourth gear shaft 17 to the inner rotor shaft 27 is equal to a reduction ratio of the fifth gear shaft 18 to the inner rotor shaft 27.

Furthermore, a seventh gear shaft 20 parallel to the sixth gear shaft 19 is further disposed on one side of the sixth gear shaft 19, the seventh gear shaft 20 is simultaneously linked with the third gear shaft 10 and the outer rotor shaft 28, the reduction ratio of the third gear shaft 10 to the sixth gear shaft 19 is equal to the reduction ratio of the third gear shaft 10 to the seventh gear shaft 20, and the reduction ratio of the sixth gear shaft 19 to the outer rotor shaft 28 is equal to the reduction ratio of the seventh gear shaft 20 to the outer rotor shaft 28.

Further, in the four-stage dead axle speed reduction structure between the input shaft 1 and the inner rotor shaft 27, the speed reduction ratio between the fourth gear shaft 17 and the inner rotor shaft 27 is the largest;

in the four-stage dead axle speed reduction structure between the input shaft 1 and the outer rotor shaft 28, the speed reduction ratio between the sixth gear shaft 19 and the outer rotor shaft 28 is the largest.

Further, the number of the power input shunt units is 1-3.

Further, the input shaft and the first gear shaft are horizontal, and the second gear shaft, the third gear shaft, the fourth gear shaft, the fifth gear shaft, the sixth gear shaft, the seventh gear shaft, the inner rotor shaft and the outer rotor shaft are vertical.

Further, a first gear 2 is fixedly arranged on the input shaft 1, and a second gear 3 is fixedly arranged on the first gear shaft 4;

a third gear 11 is fixedly arranged on the second gear shaft 9, a fourth gear 12 is fixedly arranged on the third gear shaft 10, a fifth gear 13 and a ninth gear 21 are fixedly arranged on the fourth gear shaft 17, a sixth gear 14 and a tenth gear 22 are fixedly arranged on the fifth gear shaft 18, a seventh gear 15 and an eleventh gear 23 are fixedly arranged on the sixth gear shaft 19, and an eighth gear 16 and a twelfth gear 24 are fixedly arranged on the seventh gear shaft 20;

a thirteenth gear 25 is fixedly arranged on the inner rotor shaft 27, and a fourteenth gear 26 is fixedly arranged on the outer rotor shaft 28;

the first gear 2 is meshed with the second gear 3;

the third gear 11 meshes with a fifth gear 13 and a sixth gear 14 simultaneously, and the ninth gear 21 and the tenth gear 22 mesh with a thirteenth gear 25 simultaneously;

the fourth gear 12 meshes with the seventh gear 15 and the eighth gear 16 at the same time, and the eleventh gear 23 and the twelfth gear 24 meshes with the fourteenth gear 26 at the same time.

Further, the first gear, the second gear, the third gear, the fourth gear, the fifth gear, the sixth gear, the seventh gear and the eighth gear are straight gears, the first bevel gear, the second bevel gear, the third bevel gear and the fourth bevel gear are spiral bevel gears, and the ninth gear, the tenth gear, the eleventh gear, the twelfth gear, the thirteenth gear and the fourteenth gear are herringbone gears or cylindrical gears.

The invention has the beneficial effects that:

the transmission system of the invention adopts simple ordinary gear train transmission, and is easy to realize technically. The first-stage reduction transmission is in a cylindrical gear transmission form, the arrangement mode of a reduction gear of a tail transmission system and an engine is well considered, meanwhile, the outline of a main speed reducer device is relatively flat, the flat main speed reducer can improve the installation position of the flat main speed reducer, and the space in a cabin of the helicopter is increased. The transmission system configuration of the invention can be widely applied in the fields of medium and heavy helicopter transmission systems, ship transmission systems and the like.

The bevel gear transmission system has bevel gear shunt transmission, realizes primary power shunt through the triple gear shaft, reduces the load of each path of bevel gear transmission system, reduces the gear structure limited by bearing capacity and reduces weight. Meanwhile, four-stage reduction transmission is multi-branch fixed shaft transmission, and the transmission ratio is large, so that the volume and the weight of the whole transmission system can be effectively reduced, and the stability and the reliability of the system are improved.

The third stage of the invention adopts cylindrical gear power split transmission, and after power split of bevel gear split transmission, secondary split of input power is realized, and each branch load of a transmission system is effectively reduced.

Drawings

Fig. 1 is a first schematic structural diagram according to a first embodiment of the present invention;

FIG. 2 is a second schematic structural diagram according to a first embodiment of the present invention;

FIG. 3 is a top view of a first embodiment of the present invention;

FIG. 4 is a sectional view taken along line B-B of FIG. 3;

FIG. 5 is a first schematic structural diagram according to a second embodiment of the present invention;

FIG. 6 is a second schematic structural diagram according to a second embodiment of the present invention;

FIG. 7 is a first schematic structural diagram according to a third embodiment of the present invention;

FIG. 8 is a second schematic structural diagram according to a third embodiment of the present invention;

in the figure, 1 is an input shaft, 2 is a first gear, 3 is a second gear, 4 is a first gear shaft, 5 is a first bevel gear, 6 is a second bevel gear, 7 is a third bevel gear, 8 is a fourth bevel gear, 9 is a second gear shaft, 10 is a third gear shaft, 11 is a third gear, 12 is a fourth gear, 13 is a fifth gear, 14 is a sixth gear, 15 is a seventh gear, 16 is an eighth gear, 17 is a fourth gear shaft, 18 is a fifth gear shaft, 19 is a sixth gear shaft, 20 is a seventh gear shaft, 21 is a ninth gear, 22 is a tenth gear, 23 is an eleventh gear, 24 is a twelfth gear, 25 is a thirteenth gear, 26 is a fourteenth gear, 27 is an inner rotor shaft, and 28 is an outer rotor shaft.

Detailed Description

In order to clearly explain the technical features of the present patent, the following detailed description of the present patent is provided in conjunction with the accompanying drawings.

The present invention, as shown in fig. 1-8, includes an output unit and at least one power input shunting unit;

the output unit comprises coaxial inner and outer rotor shafts 27, 28; the inner rotor shaft 27 is connected with an upper rotor, the outer rotor shaft 28 is connected with a lower rotor, the outer rotor shaft 28 is sleeved outside the inner rotor shaft 27 and keeps the same axle center, and therefore a coaxial double-rotor structure is formed;

the power input splitting unit comprises an input shaft 1, a first gear shaft 4, a second gear shaft 9, a third gear shaft 10, a fourth gear shaft 17, a fifth gear shaft 18, a sixth gear shaft 19 and a seventh gear shaft 20; the input shaft 1 is linked with the first gear shaft 4, the first gear shaft 4 is linked with the second gear shaft 9 and the third gear shaft 10 at the same time, the rotation directions of the second gear shaft 9 and the third gear shaft 10 are opposite, the second gear shaft 9, the fourth gear shaft 17 (or the fifth gear shaft 18) and the inner rotor shaft 27 are linked in sequence, and the third gear shaft 10, the sixth gear shaft 19 (or the seventh gear shaft 20) and the outer rotor shaft 28 are linked in sequence.

The second gear shaft 9 and the third gear shaft 10 are arranged in parallel to the axial direction of the output unit, and the first gear shaft 4 is arranged perpendicular to the axial direction of the output unit and is positioned below the side of the output unit;

a first bevel gear 5 and a second bevel gear 6 are fixedly arranged on the first gear shaft 4, the first bevel gear 5 and the second bevel gear 6 are oppositely arranged, and a space is reserved between the first bevel gear 5 and the second bevel gear 6; a third bevel gear 7 meshed with the first bevel gear 5 is fixedly arranged on the second gear shaft 9, and a fourth bevel gear 8 meshed with the second bevel gear 6 is fixedly arranged on the third gear shaft 10;

the third bevel gear 7 and the fourth bevel gear 8 are arranged between the first bevel gear 5 and the second bevel gear 6.

Therefore, through the optimized design of the structure, the scheme has the following advantages that:

the output unit of the scheme occupies a smaller space in the axial direction, so that the size of the transmission device can be obviously reduced, meanwhile, the configuration enables the outline of a main speed reducer device of the whole transmission system to be flat, the flat main speed reducer can improve the installation position of the flat main speed reducer device, and the space in a helicopter cabin is increased, and therefore the defects that the size of the transmission device in the prior art is difficult to further reduce, the size of the transmission device is large, the design layout is complex and the like are effectively overcome.

The structure realizes speed reduction and reversing through the shunt transmission of the bevel gears in the first gear shaft 4, enables the inner rotor shaft and the outer rotor shaft to coaxially reverse, realizes power shunting for the first time to the second gear shaft 9 and the third gear shaft 10, effectively reduces the volume and the quality of subsequent transmission gear design, and improves the stability and the reliability of a system. Meanwhile, the third-stage transmission of the structure realizes secondary power splitting, and the adopted torque splitting transmission structure can realize the large transmission ratio of the last-stage speed reduction, so that the design quality of the main speed reducer is greatly reduced, and the requirement on the large power-weight ratio of an aviation transmission system is very important.

Thirdly, the first bevel gear 5 and the second bevel gear 6 are oppositely arranged, and the third bevel gear 7 and the fourth bevel gear 8 are arranged between the first bevel gear 5 and the second bevel gear 6; therefore, more and larger space can be reserved between the first bevel gear 5 and the second bevel gear 6, so that the difficulty of the design and layout of the whole structure is further reduced, and particularly for the requirement of high-precision installation standard in aviation devices, the structure has higher practicability and feasibility, and can be used for transmission systems of medium and heavy helicopters with large input power.

Fourth, because first bevel gear 5, second bevel gear 6, third bevel gear 7, fourth bevel gear 8 have the machining error who is allowed usually in the time of the reality, consequently, because the existence of longer first gear shaft 4 this moment, will make this case can play good flexible cushioning effect with the help of the elastic deformation of first gear shaft 4 small-amplitude in the power transmission process to be favorable to all carrying, finally make the atress of two way bevel gear transmission more even, stability is better, life is longer.

The input shaft 1 and the first gear shaft 4 are linked through a reduction gear set;

the first gear shaft 4, the second gear shaft 9, the fourth gear shaft 17 (or the fifth gear shaft 18) and the inner rotor shaft 27 are linked through a speed reduction gear set in sequence; thus, a four-stage dead axle speed reduction structure is formed between the input shaft 1 and the inner rotor shaft 27;

the first gear shaft 4, the third gear shaft 10, the sixth gear shaft 19 (or the seventh gear shaft 20) and the outer rotor shaft 28 are sequentially linked through a speed reduction gear set; thus, a four-stage dead axle speed reduction structure is formed between the input shaft 1 and the outer rotor shaft 28;

the reduction ratio of the first gear shaft 4 to the inner rotor shaft 27 is equal to the reduction ratio of the first gear shaft 4 to the outer rotor shaft 28. Therefore, the inner rotor and the outer rotor finally realize the same-speed reverse rotation by matching with the second gear shaft 9 and the third gear shaft 10 with opposite rotation directions so as to achieve the torque balance of the helicopter.

A fifth gear shaft 18 parallel to the fourth gear shaft 17 is further arranged on one side of the fourth gear shaft 17, the fifth gear shaft 18 is simultaneously linked with the second gear shaft 9 and the inner rotor shaft 27, the reduction ratio of the second gear shaft 9 to the fourth gear shaft 17 is equal to the reduction ratio of the second gear shaft 9 to the fifth gear shaft 18, and the reduction ratio of the fourth gear shaft 17 to the inner rotor shaft 27 is equal to the reduction ratio of the fifth gear shaft 18 to the inner rotor shaft 27. Therefore, the third-stage speed reduction transmission structure between the input shaft 1 and the inner rotor shaft 27 is power split transmission, so that the volume and the mass of the transmission gear between the second gear shaft 9 and the inner rotor shaft 27 are effectively reduced.

A seventh gear shaft 20 parallel to the sixth gear shaft 19 is further arranged on one side of the sixth gear shaft 19, the seventh gear shaft 20 is simultaneously linked with the third gear shaft 10 and the outer rotor shaft 28, the reduction ratio of the third gear shaft 10 to the sixth gear shaft 19 is equal to the reduction ratio of the third gear shaft 10 to the seventh gear shaft 20, and the reduction ratio of the sixth gear shaft 19 to the outer rotor shaft 28 is equal to the reduction ratio of the seventh gear shaft 20 to the outer rotor shaft 28. Therefore, the third-stage speed reduction transmission structure between the input shaft 1 and the outer rotor shaft 28 is power split transmission, so that the volume and the weight of the transmission gear between the third gear shaft 10 and the outer rotor shaft 28 are effectively reduced.

In the four-stage dead axle speed reducing structure between the input shaft 1 and the inner rotor shaft 27, the speed reducing ratio of the fourth gear shaft 17 and the inner rotor shaft 27 is the largest;

in the four-stage dead axle speed reduction structure between the input shaft 1 and the outer rotor shaft 28, the speed reduction ratio between the sixth gear shaft 19 and the outer rotor shaft 28 is the largest. Therefore, the transmission ratio of the last stage in the two sets of four-stage dead axle speed reducing structures is the largest, the weight of a transmission system is favorably reduced, and the four-stage dead axle speed reducing structure has very important significance on a high-power high-speed transmission system.

The number of the power input shunt units is 1-3.

A first embodiment of the present invention is shown in fig. 1-2, having a power input splitting cell.

A second embodiment of the present invention is shown in fig. 5-6, having two power input splitting cells symmetrically disposed along the inner rotor axis.

A first embodiment of the present invention is shown in fig. 7-8, having three power input splitter units evenly distributed along the thirteenth gear axis.

The input shaft and the first gear shaft are horizontal, and the second gear shaft, the third gear shaft, the fourth gear shaft, the fifth gear shaft, the sixth gear shaft, the seventh gear shaft, the inner rotor shaft and the outer rotor shaft are vertical.

A first gear 2 is fixedly arranged on the input shaft 1, a second gear 3, a first bevel gear 5 and a second bevel gear 6 are fixedly arranged on the first gear shaft 4, and the first bevel gear 5 and the second bevel gear 6 are symmetrically arranged;

a third bevel gear 7 and a third gear 11 are fixedly arranged on the second gear shaft 9, a fourth bevel gear 8 and a fourth gear 12 are fixedly arranged on the third gear shaft 10, a fifth gear 13 and a ninth gear 21 are fixedly arranged on the fourth gear shaft 17, a sixth gear 14 and a tenth gear 22 are fixedly arranged on the fifth gear shaft 18, a seventh gear 15 and an eleventh gear 23 are fixedly arranged on the sixth gear shaft 19, and an eighth gear 16 and a twelfth gear 24 are fixedly arranged on the seventh gear shaft 20;

a thirteenth gear 25 is fixedly arranged on the inner rotor shaft 27, and a fourteenth gear 26 is fixedly arranged on the outer rotor shaft 28;

the first gear 2 is meshed with the second gear 3;

the first bevel gear 5 is meshed with a third bevel gear 7, the third gear 11 is meshed with a fifth gear 13 and a sixth gear 14 simultaneously, and the ninth gear 21 and the tenth gear 22 are meshed with a thirteenth gear 25 simultaneously;

the second bevel gear 6 meshes with a fourth bevel gear 8, the fourth gear 12 meshes with a seventh gear 15 and an eighth gear 16 simultaneously, and the eleventh gear 23 and the twelfth gear 24 mesh with a fourteenth gear 26 simultaneously.

Firstly, a first-stage cylindrical gear transmission fixed-shaft speed reduction structure is formed by a first gear 2 and a second gear 3 which are meshed.

And secondly, a second-stage bevel gear shunt transmission dead axle speed reducing structure is formed by the meshed first bevel gear 5 and third bevel gear 7, and the second bevel gear 6 and fourth bevel gear 8.

And thirdly, a third gear 11 driven by the first path of bevel gear branch is meshed with a fifth gear 13 and a sixth gear 14 simultaneously, or a fourth gear 12 driven by the second path of bevel gear branch is meshed with a seventh gear 15 and an eighth gear 16 simultaneously to form a third-stage cylindrical gear power-split transmission dead axle reduction structure.

Fourthly, a ninth gear 21 and a tenth gear 22 which are driven by the first path of bevel gear branch are meshed with a thirteenth gear 25 at the same time, or an eleventh gear 23 and a twelfth gear 24 which are driven by the second path of bevel gear branch are meshed with a fourteenth gear 26 at the same time to form a fourth-stage cylindrical gear parallel-driving transmission dead axle speed reduction structure, and the speed reduction ratio of the first stage is the largest.

The first gear, the second gear, the third gear, the fourth gear, the fifth gear, the sixth gear, the seventh gear and the eighth gear are straight gears, the first bevel gear, the second bevel gear, the third bevel gear and the fourth bevel gear are spiral bevel gears, and the ninth gear, the tenth gear, the eleventh gear, the twelfth gear, the thirteenth gear and the fourteenth gear are herringbone gears or cylindrical gears.

While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

In the description of the present invention, it should be noted that the terms "top", "bottom", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.