Compact semi-direct drive wind turbine gearbox multi-branch power split transmission structure

Abstract

The present invention discloses a compact semi-direct drive wind turbine gearbox multi-branch power split transmission structure, including a three-stage planetary gear transmission system, wherein the first-stage planetary gear transmission system is a fixed-axis internal meshing transmission, power is input from its first-stage internal gear ring, and then multiple branches are output through its multiple first-stage external gears; the second-stage planetary gear transmission system is a fixed-axis external meshing transmission, power is input from its multiple second-stage large gears, and then output through its multiple second-stage small gears; the third-stage planetary gear transmission system is a fixed-axis external meshing transmission, power is input from its multiple third-stage large gears, and is output through the third-stage center small gear. The present invention can make full use of the radial space of the original second-stage planetary transmission, and compared with the traditional compact semi-direct drive structure, the bearing capacity of the gearbox transmission is comprehensively enhanced and the transmission power is improved while keeping the space unchanged.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine gearbox transmission, and in particular to a compact semi-direct-drive wind turbine gearbox multi-branch power splitting transmission structure. Background Art

[0002] Figure 1 This is a simplified structural diagram of the gearbox of a traditional compact semi-direct-drive wind turbine generator set. It consists of a two-stage NGW planetary gear transmission system with a total speed ratio of 22-25. The first-stage planetary gear transmission system 03 has a transmission ratio of about 4.5, and the second-stage gear planetary transmission system 09 has a transmission ratio of about 5.5; the hub 04 is connected with the planetary carrier 05 and the inner ring of the main shaft bearing 06 of the first-stage planetary gear transmission system; the outer ring of the main shaft bearing 06 is connected with the box body 07 and the generator housing 08 to form the outermost structure of the wind turbine generator, replacing the nacelle of the traditional structure; the planetary carrier 010 of the second-stage planetary gear transmission system is connected with the sun gear 01 of the first-stage planetary gear transmission system through the spline 02, and the power from the blades is transmitted to the inside of the gearbox through the hub 04, and finally output to the generator by the sun gear 011 of the second-stage planetary gear transmission system;

[0003] On the existing platform, if the radial and axial dimensions of the transmission device are not changed, the main bearing model remains unchanged and can withstand the increased power, in order to increase the power of the wind turbine without changing the existing structure of the gearbox, it is necessary to increase the radial dimensions of each stage of the planetary transmission device. Although the two-stage planetary transmission has sufficient room to play in the radial space, the first-stage planetary transmission device is limited by the inner diameter of the main bearing. Therefore, the load-bearing capacity of the first-stage planetary transmission becomes a shortcoming in increasing power. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings and disadvantages of the prior art. In view of the problem that the power of the generator is limited in the traditional NGW planetary transmission gearbox, a compact semi-direct-drive wind turbine gearbox with multi-branch power split transmission structure is proposed. Under a certain spatial size of the gearbox, the transmission power can be improved and the power generation can be increased, so that the power of the wind turbine can be applied between 2.5MW and 15MW.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present invention is as follows: a multi-branch power split transmission structure of a gearbox of a compact semi-direct-drive wind turbine generator set, comprising a first-stage planetary gear transmission system, a second-stage planetary gear transmission system and a third-stage planetary gear transmission system; the first-stage planetary gear transmission system is a fixed-axis internal meshing transmission system, power is input from its first-stage internal gear ring, and then forms multiple branch outputs through its multiple first-stage external gears, the multiple first-stage external gears are evenly distributed in the first-stage internal gear ring, and are respectively meshed with the first-stage internal gear ring to evenly distribute power, the first-stage internal gear ring is fixedly connected to the hub of the wind turbine generator set, one of the first-stage external gears is installed on the cantilever end of a transmission shaft, the transmission shaft is the first transmission shaft, and is supported on the gearbox body and the bearing seat plate through the first bearing and the second bearing respectively, the bearing seat plate and the gearbox body are integrally formed; the second-stage planetary gear transmission system is a fixed-axis external meshing transmission system, the power output of the first-stage planetary gear transmission system is output by multiple second-stage large gears of the second-stage planetary gear transmission system The gear input is then output through its multiple second-stage small gears, and the second-stage large gears are respectively meshed with the adjacent second-stage small gears to form a split flow. The multiple second-stage large gears and multiple second-stage small gears are evenly distributed around the center of the gear box, and one of the second-stage large gears is installed on the first transmission shaft and is located between the first bearing and the second bearing, and one of the second-stage small gears is installed on the cantilever end of another transmission shaft, which is the second transmission shaft and is supported on the bearing seat plate through the third bearing, and both ends of the second transmission shaft are cantilever ends; the third-stage planetary gear transmission system is a fixed-axis external meshing transmission system, and the power output by the second-stage planetary gear transmission system is input by multiple third-stage large gears of the third-stage planetary gear transmission system, and then output to the generator of the wind turbine generator set through its third-stage center small gear, and the multiple third-stage large gears are evenly meshed around the third-stage center small gear, and one of the third-stage large gears is installed on the other cantilever end of the second transmission shaft, and the third-stage center small gear is located in the center of the gear box and connected to the generator.

[0006] Furthermore, the cantilever end of the second transmission shaft on which the third-stage large gear is mounted extends into the housing of the generator, so that the third-stage large gear and the third-stage central small gear are located inside the housing of the generator.

[0007] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0008] 1. The original first-stage NGW planetary transmission of the traditional compact semi-direct-drive wind turbine gearbox: The planetary transmission is divided into the internal meshing of the planetary gear and the inner ring gear and the external meshing of the planetary gear and the sun gear. Based on the principle of NGW transmission, the load-bearing capacity of the internal meshing is about 2.3 times that of the external meshing (based on the commonly used speed ratio and considering the influence of different materials of commonly used internal and external meshing gears), and the load-bearing capacity of the external meshing sun gear and / or the external meshing planet gear is the weak link of the planetary transmission (especially the external meshing sun gear). At the same time, due to the bidirectional meshing of the planetary gear teeth, the bending load-bearing capacity of the planetary gear is reduced by 30%.

[0009] Based on this, the present invention removes the sun gear from the first-stage transmission system and fixes the planet carrier. At this time, the planetary transmission is changed to the internal meshing of the fixed-axis transmission, and the planetary gear (i.e., the first-stage external gear of the transmission structure) becomes one-way meshing. Then, the inner gear ring is connected to the wheel hub to become the input part, and the planetary gear becomes the output part. In this way, the carrying capacity of the transmission is comprehensively enhanced, which provides the possibility for increasing the power. Under the condition of meeting the strength, the width and number of the planetary gear teeth can be reduced, and the first-stage transmission ratio can be increased.

[0010] 2. Since the first stage of this transmission structure is a fixed-shaft internal meshing transmission, the speed increase ratio is smaller than the original NGW planetary transmission under the condition of meeting the gear strength. If the gearbox is made into a 2-stage transmission, the total transmission speed of the gear is relatively small, so one more gear transmission is made, so that the gearbox has a total of 3 gear transmissions to achieve the required total transmission ratio. The next two stages are fixed-shaft external meshing transmissions, and the power is finally collected on the third-stage center pinion, which is directly connected to the generator, so that the transmission power is increased while keeping the space unchanged, so that the power of the wind turbine generator can be applied between 2.5MW and 15MW.

[0011] 3. The design of the present invention makes full use of the radial space of the original second-stage planetary transmission of the traditional compact semi-direct drive wind turbine gearbox, and designs a three-stage parallel shaft transmission structure (including 1-stage internal meshing and 2-stage external meshing), each stage including multi-path transmission. The appropriate speed ratio matching and structural type are selected from the perspective of gear strength and space, so as to achieve the purpose of increasing power and keeping the total transmission ratio unchanged within the original space, and provide a new transmission type for the design of the transmission gearbox for wind power generation. The above transmission routes form a multi-branch power shunt transmission structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the structure of a traditional compact semi-direct drive wind turbine gearbox.

[0013] Figure 2 This is a schematic diagram of the multi-branch power split transmission structure of the gearbox of the compact semi-direct-drive wind turbine generator set according to the present invention.

[0014] Figure 3 This is a schematic diagram of the spatial layout structure of the first-stage gear transmission system.

[0015] Figure 4 This is a schematic diagram of the spatial layout structure of the second-stage gear transmission system.

[0016] Figure 5 This is a schematic diagram of the spatial layout structure of the third-stage gear transmission system. DETAILED DESCRIPTION

[0017] The present invention will be further described below in conjunction with specific embodiments.

[0018] See also Figure 2 As shown, the compact semi-direct drive wind turbine generator gearbox multi-branch power split transmission structure provided in this embodiment includes a first-stage planetary gear transmission system, a second-stage planetary gear transmission system and a third-stage planetary gear transmission system.

[0019] The first-stage planetary gear transmission system is a fixed-axis internal meshing transmission system, in which power is inputted by its first-stage internal gear ring 1, and then outputted through a branches formed by its a first-stage external gears 2, where a=3, 4, 5..., and the a first-stage external gears 2 are evenly distributed in the first-stage internal gear ring 1, and mesh with the first-stage internal gear ring 1 respectively, so as to evenly distribute power. The first-stage internal gear ring 1 is connected to the hub 11 of the wind turbine generator set by bolts, and one of the first-stage external gears 2 is mounted on the cantilever end of a transmission shaft 10, which is the first transmission shaft, and is supported on the gear box body 12 and the bearing seat plate 14 respectively through the first bearing 9 and the second bearing 13, and the bearing seat plate 14 is fixed to the gear box body 12 as a whole.

[0020] The spatial arrangement structure of the first-stage planetary gear transmission system is shown in Figure 3 As shown (taking a=3 as an example), number 1 is an inner gear ring; numbers 2-1, 2-2, and 2-3 are three first-stage outer gears, which are evenly distributed in the first-stage inner gear ring 1 and mesh with the first-stage inner gear ring 1 respectively, and the power is evenly distributed in these three paths. Numbers 3-1, 3-2, and 3-3 indicated by dotted lines are three second-stage large gears, which are located on the same transmission shaft 10 as the first-stage outer gear 2.

[0021] The second-stage planetary gear transmission system is a fixed-axis external meshing transmission system. The power output by the first-stage planetary gear transmission system is input by the b second-stage large gears 3 of the second-stage planetary gear transmission system, and then output by the c second-stage small gears 4. The second-stage large gears 3 are respectively meshed with the adjacent second-stage small gears 4 to form a split flow. The b second-stage large gears 3 and the c second-stage small gears 4 are evenly distributed around the center of the gear box, and one of the second-stage large gears 3 is installed on the first transmission shaft and is located between the first bearing 9 and the second bearing 13. One of the second-stage small gears 4 is installed on the cantilever end of another transmission shaft 8. The transmission shaft 8 is the second transmission shaft and is supported on the bearing seat plate 14 through the third bearing 7. Both ends of the second transmission shaft are cantilever ends.

[0022] The spatial arrangement structure of the second-stage planetary gear transmission system is shown in Figure 4 As shown (taking b=3, c=3 as an example), serial numbers 3-1, 3-2, and 3-3 are three second-stage large gears, and serial numbers 4-1, 4-2, and 4-3 are three second-stage small gears, which are evenly distributed around the center of the gearbox. The second-stage large gear 3 is meshed with two adjacent second-stage small gears 4 to form a split flow, each transmitting half of the power; and the second-stage small gear 4 bears the power and speed transmitted by the two connected second-stage large gears, and the power is transmitted to the third-stage large gear after the power is combined, so the second-stage transmission forms 3 input branches and 3 output branches; serial numbers 5-1, 5-2, and 5-3 indicated by dotted lines are three third-stage large gears, which are respectively located on the same transmission shaft 8 as the second-stage small gears. The above arrangement of the transmission route makes full use of the space.

[0023] The third-stage planetary gear transmission system is a fixed-axis external meshing transmission system. The power output by the second-stage planetary gear transmission system is input by d third-stage large gears 5 of the third-stage planetary gear transmission system, and then output to the generator of the wind turbine generator set through its third-stage center pinion 6. The d third-stage large gears 5 are evenly meshed around the third-stage center pinion 6, one of the third-stage large gears 5 is installed on the other cantilever end of the second transmission shaft, and the third-stage center pinion 6 is located at the center of the gear box and connected to the generator.

[0024] The spatial arrangement structure of the third-stage planetary gear transmission system is shown in Figure 5 As shown (taking d=3 as an example), serial numbers 5-1, 5-2, and 5-3 are three third-stage gearwheels, serial number 6 is a third-stage central pinion, and serial number 15 is the housing of the generator. The cantilever end of the second transmission shaft on which the third-stage gearwheel is mounted extends into the housing 15 of the generator, so that the three third-stage gearwheels and the third-stage central pinion 6 are located in the housing 15 of the generator. The three third-stage transmission gearwheels 5-1, 5-2, and 5-3 are meshed with the third-stage central pinion 6 at the same time, and a total of three branches input power, and the power is converged and output at the third-stage central pinion 6.

[0025] In addition, the gearbox adopts a multi-branch power split transmission structure. Due to manufacturing and assembly errors, there is bound to be uneven power distribution in each branch. Therefore, this embodiment adopts a method of reducing the rigidity and increasing the flexibility of one gear in each meshing pair to solve this problem, that is, adopting a flexible pin structure, specifically, adopting a cantilever beam in the gear assembly, see Figure 2 As shown, the first-stage external gear 2 is mounted on the cantilever end of the first transmission shaft, the second-stage small gear 4 is mounted on the cantilever end of the second transmission shaft, and the third-stage large gear 5 is mounted on the other cantilever end of the second transmission shaft.

[0026] Since the cantilever beam structure will deform greatly after being stressed, it is easy to cause uneven stress on the width of the gear on it. Therefore, the above gear is designed into a special structure. After assembly, the cantilever beam end is formed in the opposite direction of the cantilever beam, forming a total of 2 cantilever structures, namely the so-called flexible pin structure. Figure 2 As shown, the first-stage external gear 2 forms a flexible pin structure with the first transmission shaft, the second-stage pinion 4 forms a flexible pin structure with the cantilever end of the second transmission shaft, and the third-stage large gear 5 forms a flexible pin structure with the other end of the second transmission shaft. When a tangential force is applied to the gear, the angular winding caused by the bending of the transmission shaft can be offset by the angular winding caused by the bending of the gear from the other end in the opposite direction. The normal force causes the flexible pin to tilt downward, while the reaction torque causes the flexible pin to tilt upward. The two opposite tilts will be offset, so that the planetary gear does not tilt as a whole, and the force is not unbalanced. Each gear moves in parallel, and the load is evenly distributed between each tooth width.

[0027] In summary, the compact semi-direct-drive wind turbine gearbox multi-branch power split transmission structure provided by the present invention can improve the transmission power while keeping the space unchanged, compared with the original compact semi-direct-drive drive structure, and provides a solution to the limited transmission power of the traditional compact semi-direct-drive wind turbine gearbox structure, which is worthy of promotion.

[0028] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Compact semi-direct drive wind turbine gearbox multi-branch power split transmission structure, including the first stage planetary gear transmission system and the second stage planetary gear transmission system, Features: The invention also comprises a third-stage planetary gear transmission system; the first-stage planetary gear transmission system is a fixed-axis internal meshing transmission system, wherein power is inputted from its first-stage internal gear ring (1) and then outputted through its plurality of first-stage external gears (2) to form a plurality of branches, wherein the plurality of first-stage external gears (2) are evenly distributed in the first-stage internal gear ring (1) and respectively mesh with the first-stage internal gear ring (1) to evenly distribute power, wherein the first-stage internal gear ring (1) is fixedly connected to the hub (11) of the wind turbine generator set, and the plurality of first-stage external gears (2) are respectively mounted on the cantilever ends of a plurality of first transmission shafts (10) and are connected to the first transmission shafts (10) via first bearings ( 9) and the second bearing (13) are supported on the gear box (12) and the bearing seat plate (14), respectively; the bearing seat plate (14) and the gear box (12) are fixed as a whole; the second-stage planetary gear transmission system is a fixed-axis external meshing transmission system; the power output by the first-stage planetary gear transmission system is input by a plurality of second-stage large gears (3) of the second-stage planetary gear transmission system, and then output through a plurality of second-stage small gears (4) thereof; the second-stage large gears (3) are respectively meshed with the second-stage small gears (4) adjacent thereto to form a split flow; the plurality of second-stage large gears (3) and the plurality of second-stage small gears (4) surround the second-stage large gears (3) and the plurality of second-stage small gears (4) The plurality of second-stage large gears (3) are evenly distributed around the center of the gearbox, and are respectively mounted on the plurality of first transmission shafts (10) and are located between the first bearing (9) and the second bearing (13); the plurality of second-stage small gears (4) are respectively mounted on the cantilever ends of the plurality of second transmission shafts (8) and are supported on the bearing seat plate (14) through the third bearing (7); both ends of the second transmission shaft (8) are cantilever ends; the third-stage planetary gear transmission system is a fixed-axis external meshing transmission system, and the power output by the second-stage planetary gear transmission system is transmitted by the plurality of third-stage large gears (5) of the third-stage planetary gear transmission system. The third-stage gear (5) is inputted and then outputted to the generator of the wind turbine generator set through its third-stage center pinion (6); the plurality of third-stage gears (5) are evenly meshed around the third-stage center pinion (6); the plurality of third-stage gears (5) are respectively mounted on the other cantilever ends of the plurality of second transmission shafts (8); the third-stage center pinion (6) is located at the center of the gearbox and is connected to the generator; the cantilever end of the second transmission shaft (8) on which the third-stage gear (5) is mounted extends into the housing (15) of the generator, so that the third-stage gear (5) and the third-stage center pinion (6) are located within the housing (15) of the generator.

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