CN216131348U

CN216131348U - Wind power gear box adopting asymmetric gear design

Info

Publication number: CN216131348U
Application number: CN202122616871.4U
Authority: CN
Inventors: 黄永平
Original assignee: CSIC Haizhuang Windpower Co Ltd
Current assignee: CSIC Haizhuang Windpower Co Ltd
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2022-03-25
Anticipated expiration: 2031-10-28

Abstract

The utility model discloses a wind power gear box adopting an asymmetric gear design. The input shaft is rotatably arranged in the box body and is connected with the hub of the wind wheel. The multi-split parallel transmission structure is arranged in the box body and is in transmission connection with the input shaft, the multi-split parallel transmission structure comprises a multi-stage gear pair, the multi-stage gear pair adopts asymmetric gears, the tooth profile of the asymmetric gears is provided with a working tooth surface and a non-working tooth surface, the pressure angle of the working tooth surface is larger than that of the non-working tooth surface, and the output shaft is in transmission connection with the multi-split parallel transmission structure. According to the wind power gear box adopting the asymmetric gear design, the pressure angle of the non-working tooth surface is properly reduced, the pressure angle of the working tooth surface is increased, the contact strength, the bending strength, the gluing reliability and the meshing efficiency of the working tooth surface are improved, and finally the performance of the gear box is greatly improved.

Description

Wind power gear box adopting asymmetric gear design

Technical Field

The utility model relates to the technical field of wind power generation, in particular to a wind power gear box adopting an asymmetric gear design.

Background

With the price balance of the wind power market, manufacturers of wind power generation sets are required to continuously reduce the manufacturing cost of the whole machine and put higher requirements on the performance of the set. In the unit construction, the cost and performance of the drive chain directly determine the cost and performance of the unit.

At present, a transmission chain in a traditional wind turbine generator set comprises parts such as a hub, a main shaft bearing, a bearing seat, a gear box, a generator, a coupler and the like, and the gear box is a key for power transmission and conversion. In a conventional wind turbine generator, a wind wheel hub is directly mounted at one end of a main shaft, one or two groups of bearings are arranged on the main shaft and are connected with a rack through a bearing seat, the other end of the main shaft is connected with an input end of a gear box through an input coupler, the gear box is usually of a multi-stage planetary speed-increasing structure, and an output shaft of the gear box is connected with a generator through an output coupler.

The working process is as follows: various loads such as wind wheel thrust, gravity, transverse load, torque and the like transmitted from the hub end are transmitted to the main shaft and act on a main shaft component; the main shaft transmits the thrust, gravity and transverse load of the wind wheel to the frame through a main shaft bearing and a bearing seat, and transmits the torque to a gear box; the gear box increases the low rotating speed and large torque transmitted by the main shaft to high speed and small torque and then transmits the torque to the generator so as to meet the working requirement of the generator.

However, in the existing traditional wind generating set gear box, the tooth profiles of all gear pairs are designed symmetrically, i.e. the tooth profiles of the working tooth surface and the non-working tooth surface are the same in shape and are symmetrically arranged. The wind power gear box mainly operates in a unidirectional mode, reverse working time is short, and the bearing capacity of a working tooth surface is limited due to the symmetrical tooth profile design, but the bearing capacity of a non-working tooth surface is surplus, so that the improvement of the bearing capacity of the wind power gear box is limited, and the performance is further improved. Moreover, the existing wind power gear box adopts a structure mainly based on planetary transmission, wherein the planetary gear still works for gear teeth on two sides in the unidirectional operation of the wind power gear box, namely the gear teeth on two sides are working gear teeth, so that the design of an asymmetric gear with more advanced performance cannot be adopted.

SUMMERY OF THE UTILITY MODEL

On the basis, the wind power gear box adopting the asymmetric gear design is provided aiming at the problem that the gear tooth profile of the gear pair of the existing gear box adopts the symmetric design, and the bearing capacity of the working tooth surface is limited due to the symmetric tooth profile design.

A wind power gearbox of asymmetric gear design comprising:

a box body;

the input shaft is rotatably arranged in the box body, extends out of the box body and is used for being connected with a hub of a wind wheel;

the multi-split parallel transmission structure is arranged in the box body and is in transmission connection with the input shaft, the multi-split parallel transmission structure comprises a multi-stage gear pair, the multi-stage gear pair adopts asymmetric gears, the tooth profile of the asymmetric gears is provided with a working tooth surface and a non-working tooth surface, and the pressure angle of the working tooth surface is larger than that of the non-working tooth surface; and

and the output shaft is rotatably arranged on the box body and is in transmission connection with the multi-shunt parallel transmission structure.

In one embodiment, the end of the input shaft for connection to the hub is enlarged in diameter to form an input flange.

In one embodiment, the multi-split parallel transmission structure comprises an input gear pair and a parallel-stage gear pair, the input gear pair comprises a first driving wheel, a first driven wheel and a first parallel shaft, the first driving wheel is mounted on the input shaft, the first parallel shaft is rotatably mounted on the box body, the first driven wheel is mounted at one end of the first parallel shaft, a plurality of first driven wheels are distributed around the first driving wheel and are meshed with the first driving wheel, and the first driving wheel and the first driven wheels are both helical gears.

In one embodiment, a first bearing is installed at one end of the first parallel shaft, the first bearings are arranged on two sides of the first driven wheel, and the first bearing on the side, away from the hub, of the first driven wheel is a thrust bearing.

In one embodiment, the parallel-stage gear pair includes a first parallel-stage gear pair and a second parallel-stage gear pair, the first parallel-stage gear is connected to the other end of the first parallel shaft, the first parallel-stage gear pair increases speed and then transmits the increased speed to the second parallel-stage gear pair, the second parallel-stage gear pair reduces the split amount through power confluence, and the output shaft is connected to the second parallel-stage gear pair.

In one embodiment, the first parallel-stage gear pair includes a second driving wheel, a second driven wheel and a second parallel shaft, the second driving wheel is mounted at the other end of the first parallel shaft, the second parallel shaft is rotatably mounted on the box body, the second driven wheel is mounted at one end of the second parallel shaft, and the second driven wheel is meshed with at least one of the second driving wheels.

In one embodiment, the first driven wheel is integrally formed on the first parallel shaft, and the second driven wheel is integrally formed on the second parallel shaft.

In one embodiment, the number of the second driving wheels is a multiple of the number of the second driven wheels, the second driven wheels are located in the area enclosed by the second driving wheels, and each second driven wheel is meshed with a plurality of second driving wheels.

In one embodiment, the second parallel-stage gear pair includes a third driving wheel and a third driven wheel, the third driving wheel is mounted at the other end of the second parallel shaft, the third driven wheel is mounted on the output shaft, and the third driven wheel is meshed with a plurality of the third driving wheels.

In one embodiment, a connecting shaft penetrates through the output shaft, the third driven wheel is integrally formed on the connecting shaft, and the connecting shaft is flexibly connected with the output shaft.

The wind power gear box adopting the asymmetric gear design at least has the following advantages:

(1) by adopting the design of the asymmetric gear, the pressure angle of the non-working tooth surface is properly reduced, the pressure angle of the working tooth surface is increased, the contact strength, the bending strength, the gluing reliability and the meshing efficiency of the working tooth surface are improved, and finally the performance of the gear box is greatly improved.

(2) The gearbox design incorporates the spindle function. The transmission chain of the unit adopting the gear box cancels a separate main shaft component which comprises a main shaft, a main shaft support bearing and a bearing seat structure. The structure of the transmission chain is greatly simplified, the cost is greatly reduced, the installation and debugging of the transmission chain are simplified, and the reliability of the transmission chain is improved.

(3) The input end of the gear box is provided with an input flange. The input coupling is cancelled in the unit transmission chain adopting the gear box, and the hub is directly and rigidly connected with the flange of the input shaft of the gear box. Because no large-scale input coupler is arranged, the structure of the transmission chain is simplified, the risk brought by the coupler is reduced, the cost is also reduced, and the installation of the transmission chain is simplified.

(4) The transmission chain of the unit adopting the gear box has the advantages that the main shaft part and the input coupler are omitted, the length of the transmission chain is greatly shortened, the length of the rack is correspondingly greatly shortened, the weight is greatly reduced, the structural design difficulty of the rack is simplified, the lightweight design of the rack is facilitated, and the cost of the rack is reduced.

(5) The transmission chain of the unit adopting the gear box is free of a main shaft part and an input coupler, and meanwhile, the light weight design of the rack is adopted, so that the weight of the unit is greatly reduced, the hoisting requirement of the whole unit is reduced, and the hoisting cost is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention, the drawings, which are required to be used in the embodiments, will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to actual scale.

FIG. 1 is a schematic diagram of a gearbox connecting hub and generator using a multi-split parallel transmission configuration according to an embodiment;

FIG. 2 is a schematic diagram of a multi-split parallel transmission structure of a gearbox according to an embodiment;

FIG. 3 is a schematic view of another perspective of the multi-split parallel transmission configuration of the gearbox of FIG. 2;

FIG. 4 is a schematic structural view of an asymmetric gear tooth profile according to an embodiment

FIG. 5 is a front view of the gearbox of FIG. 1 utilizing a multiple split parallel transmission configuration;

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5;

FIG. 7 is a cross-sectional view taken along line B-B of FIG. 5;

fig. 8 is a cross-sectional view taken along line C-C of fig. 5.

Reference numerals:

10-wheel hub, 20-gear box, 202-working tooth surface, 204-non-working tooth surface, 21-box, 22-input shaft, 221-support bearing, 222-input flange, 223-connecting boss, 23-input gear pair, 231-first driving wheel, 232-first driven wheel, 233-first parallel shaft, 234-first bearing, 24-parallel stage gear pair, 241-second driving wheel, 242-second driven wheel, 243-second parallel shaft, 244-third driving wheel, 245-third driven wheel, 246-connecting sleeve, 25-output shaft, 26-connecting shaft, 27-spline, 30-generator and 40-frame.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather construed as embodying the utility model in accordance with the principles of the utility model.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model.

Referring to fig. 1, in an embodiment, a wind turbine gearbox 20 with an asymmetric gear design is used to connect a hub 10 and a generator 30, so as to increase the low rotation speed and the large torque of the hub 10 to a high speed and a small torque, and then transmit the high speed and the small torque to the generator 30.

Referring to fig. 2 and 3, in one embodiment, the wind power gearbox 20 adopting an asymmetric gear design includes a box 21, an input shaft 22, a multi-split parallel transmission structure and an output shaft 25.

The input shaft 22 is rotatably mounted in the housing 21, and the input shaft 22 extends out of the housing 21 for connection with the hub 10 of the wind wheel. Specifically, the input shaft 22 is provided with support bearings 221 at intervals, and the support bearings 221 are mounted on the box body 21, so that the input shaft 22 can be rotatably mounted in the box body 21. One end of the input shaft 22 gradually increases in diameter in a direction away from the case 21 and is formed with an input flange 222, and the input flange 222 is rigidly connected to the hub 10 by bolts, so that the input shaft 22 is connected to the hub 10.

Referring to fig. 4, the multi-split parallel transmission structure is installed in the box 21, and the multi-split parallel transmission structure is in transmission connection with the input shaft 22. The multi-split parallel transmission structure is used for realizing speed-increasing transmission, low-speed large torque transmitted from the input shaft 22 is subjected to multi-split power, multi-stage speed increasing, and finally power confluence is carried out and is transmitted to the generator 30 through the output shaft 25. The multi-split parallel transmission structure comprises a multi-stage gear pair, and the multi-stage gear pair adopts asymmetric gears. The asymmetric gear profile has a working flank 202 and a non-working flank 204, the pressure angle of the working flank 202 being greater than the pressure angle of the non-working flank 204.

The radius of curvature of the tooth profile is increased by increasing the pressure angle of the working tooth surface 202, so that the contact stress of the tooth surface is reduced, and the contact strength is improved; the bending moment of the gear teeth under load is reduced, the bending stress is reduced, and the bending strength is improved; the sliding between the tooth surfaces is reduced, the friction loss is reduced, the efficiency is improved, the gluing risk is reduced, and the gluing safety is improved. Ultimately, the durability of the working tooth surface 202 is improved, resulting in lighter weight or greater reliability. For the non-working tooth surface 204, the width of the tooth top can be increased by reducing the pressure angle, the reduction of the tooth top caused by increasing the pressure angle of the working tooth surface 202 is compensated, the tooth top is kept to have a certain thickness, and the collapse damage in the working process is avoided; meanwhile, the non-working tooth surface 204 works in the reverse running, and since the working time is short, the proper reduction of the contact and bending strength does not affect the running reliability.

Referring to fig. 2 and fig. 3 again, in one embodiment, the multi-split parallel transmission structure includes an input gear pair 23 and a parallel gear pair 24, the input gear pair 23 is connected to the input shaft 22, the parallel gear pair 24 is connected to the input gear pair, the output shaft 25 is connected to the parallel gear pair 24, and the output shaft 25 extends out of the box 21 and is connected to the generator 30.

In one embodiment, the input gear pair 23 includes a first driving pulley 231, a first driven pulley 232 and a first parallel shaft 233, the first driving pulley 231 is mounted at the middle of the input shaft 22, and the first driving pulley 231 is located in the casing 21. Specifically, the input shaft 22 is provided with a connecting boss 223, and the first driving wheel 231 is mounted on the connecting boss 223 through a bolt, so that the first driving wheel 231 is mounted on the input shaft 22. The first parallel shaft 233 is rotatably installed on the case 21, the first driven pulley 232 is installed at one end of the first parallel shaft 233, the plurality of first driven pulleys 232 are distributed around the first driving pulley 231 and engaged with the first driving pulley 231, and both the first driving pulley 231 and the first driven pulley 232 are helical gears.

Referring to fig. 4 and 5, in one embodiment, the number of the first driven wheels 232 is at least two, and preferably an even number. Specifically, in the present embodiment, the number of the first driven wheels 232 is 8. The first driven wheels 232 may be evenly distributed around the input shaft 22 or unevenly distributed, as desired. In this embodiment, the first driven wheels 232 are uniformly distributed around the input shaft 22, so as to ensure uniform stress on the first driving wheels 231.

On the basis of the above embodiment, further, the first parallel shafts 233 are parallel to the input shaft 22, the number of the first parallel shafts 233 is the same as the number of the first driven wheels 232, a plurality of the first parallel shafts 233 are distributed around the input shaft 22, and one first driven wheel 232 is mounted on each first parallel shaft 233. The first parallel shaft 233 is provided with a first bearing 234, and the first bearing 234 is mounted on the case 21, so that the first parallel shaft 233 is rotatably mounted in the case 21. First bearings 234 are arranged on two opposite sides of the first driven wheel 232, and the first bearing 234 on the side, away from the hub 10, of the first driven wheel 232 is used for bearing thrust so as to bear axial thrust of the first driven wheel 232 and transmit the axial thrust to the box body 21.

Wherein, the load that the wind wheel produced all acts on wheel hub 10, because wheel hub 10 is directly connected with the input shaft 22 rigid of gear box 20, wind wheel thrust, gravity, moment of torsion, the horizontal load from wheel hub 10 are all transmitted to input shaft 22. The input shaft 22 transmits the torque to the first driving wheel 231 installed at the middle portion thereof, and the first driving wheel 231 is simultaneously engaged with the plurality of first driven wheels 232, thereby achieving power split transmission and speed increase transmission.

Because the input gear pair 23 adopts the helical gear design, axial forces with the same magnitude and opposite directions are generated on the first driving wheel 231 and the first driven wheel 232 during meshing, and by selecting a proper helical angle, most or all of the axial forces on the first driving wheel 231 and the wind wheel thrust transmitted by the input shaft 22 can be offset, so that the load borne by the support bearing 221 is greatly reduced. The weight of hub 10, the lateral loads and a small part of the remaining rotor thrust are transmitted to casing 21 via support bearings 221 at both ends of input shaft 22 and further to frame 40. The axial force borne by the first driven wheel 232 is transmitted to the thrust bearings, and since the first driven wheel 232 is in multi-split transmission and the number of the thrust bearings is correspondingly multiple, each thrust bearing only bears part of the axial force, and the axial force is transmitted to the box body 21 after being dispersedly borne by the thrust bearing and is transmitted to the frame 40 through the box body 21.

In one embodiment, the parallel gear pair 24 includes a first parallel gear pair and a second parallel gear pair, the first parallel gear pair is connected to the other end of the first parallel shaft 233, the first parallel gear pair is accelerated and then transmitted to the second parallel gear pair, the second parallel gear pair reduces the split amount by power convergence, and the output shaft 25 is connected to the second parallel gear pair.

In addition to the above embodiments, the first parallel-stage gear pair further includes a second driving wheel 241, a second driven wheel 242 and a second parallel shaft 243. The second driving pulley 241 is mounted to the other end of the first parallel shaft 233, and the first driven pulley 232 and the second driving pulley 241 are respectively located at both ends of the first parallel shaft 233. A second parallel shaft 243 is rotatably installed in the case 21, a second driven pulley 242 is installed at one end of the second parallel shaft 243, and the second driven pulley 242 is engaged with at least one second driving pulley 241. The second parallel stage gear pair includes a third primary pulley 244 and a third secondary pulley 245. A third driving pulley 244 is mounted on the other end of the second parallel shaft 243, a third driven pulley 245 is mounted on the output shaft 25, and the third driven pulley 245 is simultaneously meshed with the plurality of third driving pulleys 244.

The process of increasing the speed of the low-speed large torque to the high-speed small torque by the gearbox 20 is specifically as follows: the first driving wheel 231 drives the first driven wheel 232 to rotate, and since the first driving wheel 231 is meshed with the plurality of first driven wheels 232, the first driven wheels 232 can be accelerated, so that the first-time acceleration transmission is realized.

The first parallel shaft 233 then transmits torque to the second drive wheel 241, and the second drive wheel 241 drives the second driven wheel 242 in rotation. A second step-up drive is achieved in that each secondary driven pulley 242 engages at least one secondary drive pulley 241.

Finally, the second parallel shaft 243 transfers the torque to the third driving wheel 244, and the third driving wheel 244 drives the third driven wheel 245, and thus the output shaft 25. A third step-up drive is achieved because the third driven pulley 245 engages the plurality of third drive pulleys 244. The gear box 20 realizes the speed increase from low rotating speed and large torque to high speed and small torque through three times of speed increasing transmission.

Referring to fig. 3 and 6, in addition to the above embodiment, the number of the second driving wheels 241 is the same as the number of the first driven wheels 232, and each second driving wheel 241 is installed on the corresponding first parallel shaft 233. In this embodiment, the number of the second driving wheels 241 is 8. The number of the second driving wheels 241 is a multiple of the number of the second driven wheels 242, the second driven wheels 242 are located within a circumferential range surrounded by the second driving wheels 241, so that the second driven wheels 242 are conveniently meshed with the second driving wheels 241, and each second driven wheel 242 is meshed with a plurality of second driving wheels 241, thereby realizing speed-increasing transmission.

Specifically, in the present embodiment, the number of the second driving wheels 241 is twice as many as the number of the second driven wheels 242, that is, the number of the second driven wheels 242 is 4, and each of the second driven wheels 242 engages with two adjacent second driving wheels 241. It is understood that in other embodiments, the number of the second driving wheels 241 may be 1 times the number of the second driven wheels 242, the second driven wheels 242 are engaged with the second driving wheels 241 individually, or the number of the second driving wheels 241 and the number of the second driven wheels 242 are 1 times, 2 times or 3 times respectively according to different circumferential distribution positions, as long as each second driven wheel 242 can be normally engaged with the second driving wheel 241.

Referring also to fig. 7, in one embodiment, the second parallel shafts 243 are rotatably mounted in the housing 21 by bearings, the number of the second parallel shafts 243 is the same as that of the second driven pulleys 242, and one second driven pulley 242 is mounted on each second parallel shaft 243. The second parallel axis 243 is parallel to the first parallel axis 233, and the second parallel axis 243 is located between the first parallel axis 233 and the input shaft 22. The number of the third driving wheels 244 is the same as that of the second parallel shafts 243, and the second driven wheels 242 and the third driving wheels 244 are respectively installed at two ends of the second parallel shafts 243. In the present embodiment, the number of the third driving pulleys 244 is 4.

In one embodiment, the first driven wheel 232 is integrally formed on the first parallel shaft 233, the second driven wheel 242 is integrally formed on the second parallel shaft 243, and the first parallel shaft 233 and the second parallel shaft 243 are both gear shafts, so that the installation process is simple and the structure is compact. The third driving pulley 244 surrounds the third driven pulley 245, and a plurality of the third driving pulleys 244 are engaged with the third driven pulley 245. In the present embodiment, 4 third driving wheels 244 are engaged with the third driven wheels 245.

In one embodiment, a connecting sleeve 246 is disposed on the second parallel shaft 243, and the third driving wheel 244 is mounted on the connecting sleeve 246 by bolts, so that the third driving wheel 244 is mounted on the second parallel shaft 243. The output shaft 25 is rotatably mounted on the box body 21, a connecting shaft 26 penetrates through the output shaft 25, a third driven wheel 245 is integrally formed on the connecting shaft 26, and the connecting shaft 26 is flexibly connected with the output shaft 25. The connection shaft 26 and the output shaft 25 are flexibly connected, so that the output shaft 25 can be angularly or radially offset relative to the connection shaft 26, and the connection of the output shaft 25 and the generator 30 and the uniform load of the third driven wheel 245 are facilitated. Specifically, the connecting shaft 26 is flexibly connected to the output shaft 25 by a spline 27.

According to the wind power gear box 20 adopting the asymmetric gear design, the main shaft function is integrated in the structural design of the gear box. The gear box input shaft 22 performs a main shaft function, the gear box input shaft 22 support bearing 221 performs a main shaft bearing function, and the gear box body 21 performs a bearing seat function. Therefore, in the unit transmission chain using the novel gear box, a main shaft bearing and a main shaft bearing seat are not required to be independent. The input shaft 22 is provided with an input flange 222, and in a unit transmission chain using the novel gearbox, an input coupling is not needed, and the wind wheel hub 10 is directly and rigidly mounted on the input flange 222 of the input shaft 22. The input gear pair 23 adopts a helical gear structure, and the meshing axial force is opposite to the wind wheel thrust direction from the hub 10 and directly acting on the input shaft 22 and is close to the wind wheel thrust direction by selecting reasonable parameters, so that the offsetting effect is generated. The support bearing 221 of the input shaft 22, which performs the function of a main shaft bearing, is thus not subjected to the operational thrust of the rotor or is subjected to only a small thrust. All gear pairs adopt asymmetric gear design, so that the contact strength, the bending strength, the gluing reliability and the meshing efficiency of the gears are improved, and finally, the performance of the gear box is greatly improved.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; while the utility model has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention, and they should be construed as being included in the following claims and description.

Claims

1. The utility model provides an adopt wind-powered electricity generation gear box of asymmetric gear design which characterized in that includes:

a box body;

2. The wind power gearbox of claim 1, wherein the end of the input shaft for connection to the hub is enlarged in diameter to form an input flange.

3. The wind power gearbox adopting the asymmetric gear design as claimed in claim 2, wherein the multi-split parallel transmission structure comprises an input gear pair and a parallel stage gear pair, the input gear pair comprises a first driving wheel, a first driven wheel and a first parallel shaft, the first driving wheel is mounted on the input shaft, the first parallel shaft is rotatably mounted on the box body, the first driven wheel is mounted at one end of the first parallel shaft, the first driven wheels are distributed around the first driving wheel and meshed with the first driving wheel, and the first driving wheel and the first driven wheels are both helical gears.

4. The wind power gearbox adopting the asymmetric gear design as defined in claim 3, wherein a first bearing is installed at one end of the first parallel shaft, the first bearings are respectively installed at two sides of the first driven wheel, and the first bearing at one side of the first driven wheel far away from the hub is a thrust bearing.

5. The wind power gearbox adopting the asymmetric gear design as claimed in claim 3, wherein the parallel stage gear pair comprises a first parallel stage gear pair and a second parallel stage gear pair, the first parallel stage gear is connected with the other end of the first parallel shaft, the first parallel stage gear pair is accelerated and then transmitted to the second parallel stage gear pair, the second parallel stage gear pair reduces the split number through power confluence, and the output shaft is connected with the second parallel stage gear pair.

6. The wind power gearbox adopting an asymmetric gear design as claimed in claim 5, wherein the first parallel-stage gear pair comprises a second driving wheel, a second driven wheel and a second parallel shaft, the second driving wheel is mounted at the other end of the first parallel shaft, the second parallel shaft is rotatably mounted on the box body, the second driven wheel is mounted at one end of the second parallel shaft, and the second driven wheel is meshed with at least one second driving wheel.

7. The wind power gearbox of claim 6, wherein said first driven pulley is integrally formed on said first parallel shaft and said second driven pulley is integrally formed on said second parallel shaft.

8. The wind power gearbox adopting an asymmetric gear design as defined in claim 6, wherein the number of the second driving wheels is a multiple of the number of the second driven wheels, the second driven wheels are located in an area enclosed by the second driving wheels, and each second driven wheel is meshed with a plurality of the second driving wheels.

9. The wind power gearbox adopting an asymmetric gear design as claimed in claim 6, wherein the second parallel stage gear pair includes a third driving wheel and a third driven wheel, the third driving wheel is mounted at the other end of the second parallel shaft, the third driven wheel is mounted on the output shaft, and the third driven wheel is meshed with the plurality of third driving wheels.

10. The wind power gearbox adopting the asymmetric gear design as defined in claim 9, wherein a connecting shaft penetrates through the output shaft, the third driven wheel is integrally formed on the connecting shaft, and the connecting shaft is flexibly connected with the output shaft.