A main shaft system of a wind turbine generator

Abstract

The invention discloses a main shaft system of a wind turbine generator, which relates to the technical field of wind power generation, and comprises a fixed shaft, a rotating shaft and two bearings. The rotating shaft sleeve is arranged outside the shaft main body of the fixed shaft, and a disc I and a disc II are arranged outside the rotating shaft sleeve, and a reinforcing rib I is arranged between the disc I and the disc II; a concave structure is arranged at the transition between the shaft main body of the fixed shaft and the disc flange, and a transition ring is arranged in the concave structure, and the transition ring extends axially to the bearing outside the concave structure, and the transition ring and the bearing have an interference fit, and the outer cylindrical surface of the transition ring has an interference fit with the rotating shaft, and the inner cylindrical surface of the transition ring has a clearance fit with the fixed shaft. The rotating shaft sleeve is arranged outside the shaft main body of the fixed shaft, and has a stronger bearing capacity; the rotating shaft adopts a double disc shared reinforcing rib structure, so that the overall rigidity of the shaft system structure is strong, and the structure is simple, the weight is light, and the economy is good; the transition ring is arranged at the concave structure, and on the basis of meeting the structural use requirements, the stress concentration factor of the fixed shaft is greatly reduced, and the use requirements of large MW-class units are met.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a main shaft system of a wind power generator. Background Art

[0002] A wind turbine generator set is mainly composed of blades, hubs, generators, main frames, towers and other components. Wind energy is captured by blades. The roots of the blades are installed on the hub. The rotation of the blades converts wind energy into kinetic energy. The wind energy is transmitted to the generator through the hub, and finally the kinetic energy is converted into electrical energy through the generator.

[0003] The generator is mainly composed of a stator, a rotor, a shaft system and auxiliary components. The stator and rotor realize the conversion of mechanical energy into electrical energy. The shaft system structure is the main load transfer path. During the energy conversion process, the shaft system structure not only bears the torque generated by the rotation of the unit, but also bears various complex alternating loads, such as radial load, axial load, bending moment, etc. These loads are affected by various factors during the operation of the wind turbine and are prone to various faults. Therefore, the safety performance of the shaft system structure plays a decisive role in the normal operation of the wind turbine.

[0004] In addition, as the power of wind turbines gradually increases, the load on the shaft system also increases sharply, and the corresponding shaft system structure size also increases accordingly. At the same time, the intensified market competition requires the unit cost of wind turbines to be lower and lower, while the reliability requirements are getting higher and higher. These factors have put forward higher requirements for the design and manufacture of the shaft system.

[0005] In summary, the function of the main shaft system of a wind turbine is not only to transmit torque, but also to withstand complex alternating loads. Therefore, the shaft system structure of a wind turbine generator set faces the dual challenges of performance and manufacturing cost.

[0006] The utility model patent with publication number CN210343620U discloses a shaft system structure of a direct-drive wind turbine generator, including a fixed shaft engaged on a main frame and a rotating shaft engaged on a wheel hub, an upwind bearing and a downwind bearing supporting the rotation of the rotating shaft are arranged on the outer side of the fixed shaft, the cross section of the side wall of the rotating shaft is a "human" shaped structure, the upwind bearing and the downwind bearing are respectively located at the two ends of the "human" shaped structure, the third end of the "human" shaped structure is engaged on the wheel hub, and extends outward along the third end to form a disc structure located on the outer ring of the rotating shaft; the cross section of the side wall of the fixed shaft is an L-shaped structure, the upwind bearing is located at one end of the fixed shaft, and the other end of the fixed shaft is engaged on the main frame.

[0007] However, the above patent has the following problems:

[0008] 1. The above patent uses two tapered roller bearings of equal size to provide support for the unit. When installing the bearings, the shrink fit method is adopted. The equal size design brings higher requirements to the installation and increases the difficulty of assembly. The bearing span is greater than or equal to 2 times the distance from the mating surface between the rotating shaft and the hub to the mating surface between the fixed shaft and the main frame. The entire shaft system is very long, the overall size is large, and the weight is heavy.

[0009] 2. The above patent adopts two small bearings of equal size, and the bearing and shaft system have weak bearing capacity. As the wind load increases, the bearing and shaft structure cannot meet the use requirements and is not suitable for large MW wind turbines;

[0010] 3. The shaft system design of the above patent has a low degree of integration and only realizes the basic functions of the shaft system, providing support for the unit and bearing wind loads. Summary of the invention

[0011] The present invention aims to provide a main shaft system of a wind turbine generator, which adopts two large single-row tapered roller bearings of different sizes to provide support for the shaft system, and adopts an outer ring rotating structure, and the bearing has a strong bearing capacity, which can meet the use requirements of large MW-class units; at the same time, the two bearings are of different sizes, which provides convenience for the installation of the bearings and reduces the difficulty of bearing assembly. The bearing span is small, which is approximately equal to the distance from the mating surface of the rotating shaft and the hub to the mating surface of the fixed shaft and the main frame, and the overall size is small, the structure is compact, and the weight is light.

[0012] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0013] A main shaft system of a wind turbine generator comprises a fixed shaft engaged on a main frame, a rotating shaft engaged on a wheel hub and two bearings providing support for the shaft system, wherein the fixed shaft comprises a shaft main body and a disc flange, the rotating shaft sleeve is arranged outside the shaft main body of the fixed shaft, a disc I and a disc II are arranged outside the rotating shaft, the disc II is located at one end of the rotating shaft close to the disc flange, the disc I is located in the middle of the rotating shaft, a reinforcing rib I running through the two discs is arranged between the disc I and the disc II, the side of the disc I not provided with the reinforcing rib I is engaged with the wheel hub, the end face of the disc flange of the fixed shaft away from the shaft main body is engaged with the main frame, and two bearings are respectively arranged on the inner circular surfaces at both ends of the rotating shaft The outer cylindrical surface of the bearing is interference fit with the inner cylindrical surface of the rotating shaft, and the inner cylindrical surface of the bearing is respectively interference fit with the outer cylindrical surfaces at both ends of the shaft main body of the fixed shaft, and the outer cylindrical surface of the disc flange part of the fixed shaft close to the shaft main body side is sleeved with a fixed shaft disc, and the fixed shaft disc is engaged with the stator bracket; an inner concave structure is provided at the transition between the shaft main body and the disc flange part of the fixed shaft, and the inner surface of the inner concave structure adopts multiple arcs with an inner fillet R greater than 50°, and the multiple arcs have smooth transitions. A transition ring is arranged in the inner concave structure, and the transition ring extends axially to the bearing outside the inner concave structure, the transition ring is interference fit with the bearing, the outer cylindrical surface of the transition ring is interference fit with the fixed shaft, and the inner cylindrical surface of the transition ring is clearance fit with the fixed shaft.

[0014] The end surface of the fixed shaft body away from the disc flange is provided with a bearing pressing ring engaged with the fixed shaft end face flange, and the bearing pressing ring provides axial preload for the bearing to ensure safe and stable operation of the bearing.

[0015] The end surface of the rotating shaft away from the disc II is provided with a brake disc engaged with the rotating shaft, and the bearing pressure ring is provided with a brake matched with the brake disc to realize the braking function of the shaft system;

[0016] The upper handle of the bearing pressure ring is equipped with a brake protective cover to provide protection for the brake and brake disc;

[0017] The fixed axis disc is provided with reinforcing ribs II for increasing rigidity;

[0018] The two bearings are both single-row tapered roller bearings, the outer diameters of the two bearings are greater than 3 meters, the two bearings are of different sizes, and the difference in outer diameters of the two bearings is less than 100 mm, and the bearing span is smaller than the outer diameter of any one of the bearings; the axial dimension of the entire shaft system is shortened, the structure is compact and light, and the economy of the unit is improved.

[0019] The inner diameter of the bearing on the side away from the fixed axis disc of the two bearings is smaller than the inner diameter of the bearing on the side close to the fixed axis disc. When the bearing is assembled, the fixed axis disc side faces the ground. The downwind bearing is installed first and moved axially to the transition ring through the shaft end away from the axis disc side. The design of this size provides convenience for bearing installation and reduces the difficulty of assembly.

[0020] Wedge-shaped seals for sealing bearing grease are arranged at both ends of the rotating shaft. The wedge-shaped seals are installed between the fixed shaft and the rotating shaft. When the bearing is working, good lubrication must be ensured. The wedge-shaped seals prevent the loss of bearing grease, thus providing a guarantee for good bearing lubrication.

[0021] The fixed shaft is provided with a grease removal maintenance hole, the rotating shaft is provided with a waist-shaped hole for bearing maintenance along the circumferential direction, and an easily detachable cover plate is provided on the waist-shaped hole.

[0022] Beneficial effects of the present invention:

[0023] 1. In the present invention, two large-sized but unequal-sized single-row tapered roller bearings are selected, and an outer ring rotating structure is adopted. Compared with the traditional bearing inner ring rotating structure, when the bearing size and bearing span are the same, the outer ring rotating structure has a stronger bearing capacity, which not only meets the use requirements of large MW units, but also further reduces costs and improves the safety and economy of the structure.

[0024] 2. In the present invention, the shaft system structure close to one side of the rotating shaft disc I is all located inside the hub, which reasonably utilizes the internal space of the hub, making the unit structure more compact, greatly shortening the installation distance from the hub center to the main frame, reducing the force generated by the blade load on the yaw bearing, and making the structure of the entire unit more compact, lower in cost, and better in economy.

[0025] 3. In the present invention, the rotating shaft adopts a double-disc common reinforcing rib I structure, which is simple, light, and rigid. Under the action of wind load, its deformation is small, ensuring the safe and stable operation of the bearing. At the same time, it reduces the deformation of the air gap of the generator, reduces the risk of stator-rotor collision, and improves the stability of the air gap of the generator. Further, the uniformity of the air gap of the generator is increased, reducing the risk of generator vibration caused by uneven air gap. Or when designing the generator, under the condition of meeting the electromagnetic performance, the air gap value can be further reduced, reducing the amount of effective materials such as copper and magnetic steel, and improving the economic efficiency of the generator.

[0026] 4. In the present invention, the transition between the fixed shaft body and the flange disc structure adopts a concave structure with multiple large R smooth arc transitions, and a transition ring is provided at the concave structure. Due to the sudden change in the cross section at the transition between the fixed shaft body and the flange disc structure, stress concentration will occur under the action of wind load. A large stress concentration coefficient will cause the stress of the shaft system to exceed the standard. Traditional methods for reducing the stress concentration coefficient include using fillets, smooth transition curves, etc. The larger the fillet radius, the smoother the smooth transition, and the smaller the stress concentration coefficient. The cleverness of the present invention lies in the use of a concave multi-segment large R smooth arc transition structure plus a transition ring structure, which not only reduces the stress concentration coefficient of the shaft system structure, but also provides axial support for the bearing, ensuring the basic function of the shaft system structure. Only using a concave multi-segment large R smooth arc transition structure can reduce the stress concentration coefficient of the shaft system, but cannot provide axial support for the bearing and cannot ensure the stable operation of the bearing. The structural design of the concave small fillet can meet the function of providing axial support for the bearing, but cannot effectively reduce the stress concentration coefficient. Therefore, the ingenious design of the structure not only ensures that the stress level of the shafting structure meets the requirements, but also provides effective support for the bearings, meeting the use requirements of large MW-class units.

[0027] 5 In the present invention, the shaft system structure adopts a highly integrated design. A locking seat is designed on the second disc of the rotating shaft. Multiple locking seats are evenly arranged along the circumference of the second disc of the rotating shaft. Under the action of the hydraulic system, the locking pin extends axially to the locking seat, realizing the locking function of the unit. At the same time, a brake disc for braking the unit is arranged on the side of the rotating shaft close to the hub, and a brake engaged on the bearing pressure ring. Under the action of the hydraulic system, the brake pad and the brake disc are braked by friction, realizing the braking function of the unit.

[0028] 6. The shaft system structure of the present invention adopts two large bearing designs and an outer ring rotating structure. The bearing has a strong load-bearing capacity and meets the use requirements of large-power units. The rotating shaft adopts a double-disc single-rib I structure, which greatly improves the overall stiffness of the shaft system, reduces the deformation of the unit under wind load, improves the stability of the generator air gap, and reduces the risk of stator and rotor rubbing. At the same time, the generator air gap is more uniform, reducing the risk of vibration. Further, the use of effective materials such as generator magnets and copper can be reduced, greatly improving the economy of the unit. The fixed shaft adopts a transition ring to increase the concave structure of R, which reduces the stress concentration factor of the shaft system and meets the use requirements of large MW-class units. Furthermore, the locking and braking structures are centrally designed on the shaft system structure, and the overall structural design of the unit is compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of the main shaft system of the wind turbine generator in the present invention.

[0030] Figure 2 It is a schematic diagram of the concave structure of the main shaft system of the wind turbine generator in the present invention.

[0031] Figure 3 The figure is a schematic diagram of the brake structure of the main shaft system of the wind turbine generator in the present invention.

[0032] Among them, 1. fixed shaft; 2. rotating shaft; 3. bearing; 4. main frame; 5. wheel hub; 6. stator bracket; 7. disc I; 8. disc II; 9. shaft body; 10. disc flange; 11. reinforcing rib I; 12. concave structure; 13. transition ring; 14. bearing pressure ring; 15. brake disc; 16. brake; 17. wedge seal; 18. brake protective cover. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] like Figure 1-3The embodiment shown provides a main shaft shaft system of a wind turbine generator, including a fixed shaft 1 engaged on a main frame 4, a rotating shaft 2 engaged on a hub 5, and two bearings 3 providing support for the shaft system, wherein the fixed shaft 1 includes a shaft body 9 and a disc flange 10, the rotating shaft 2 is sleeved on the outside of the shaft body 9 of the fixed shaft 1, and a disc I7 and a disc II8 are arranged on the outer side of the rotating shaft 2, the disc II8 is located at one end of the rotating shaft 2 close to the disc flange 10, and the disc I7 is located in the middle of the rotating shaft 2, and a reinforcing rib I11 is arranged between the disc I7 and the disc II8 and passes through the two discs, and the side of the disc I7 without the reinforcing rib I11 is engaged with the hub 5, and the end face of the disc flange 10 of the fixed shaft 1 away from the shaft body 9 is engaged with the main frame 4, and the two bearings 3 are respectively arranged on both sides of the rotating shaft 2 The inner circular surface of the end, the outer circular surface of the bearing 3 and the inner circular surface of the rotating shaft 2 are interference fit, the inner circular surface of the bearing 3 are respectively interference fit with the outer circular surfaces at both ends of the shaft main body 9 of the fixed shaft 1, and the outer circular surface of the disc flange part 10 of the fixed shaft 1 close to the shaft main body 9 is sleeved with a fixed shaft disc, and the fixed shaft disc is engaged with the stator bracket 6; a concave structure 12 is provided at the transition between the shaft main body 9 and the disc flange part 10 of the fixed shaft 1, and the inner surface of the concave structure 12 adopts multiple sections of arcs with an inner fillet R greater than 50°, and the multiple sections of arcs are smoothly transitioned. A transition ring 13 is arranged in the concave structure 12, and the transition ring 13 extends axially to the bearing 3 outside the concave structure, the transition ring 13 and the bearing 3 are interference fit, the outer circular surface of the transition ring 13 and the fixed shaft 1 are interference fit, and the inner circular surface of the transition ring 13 and the fixed shaft 1 are clearance fit.

[0036] In this embodiment, the main shaft shaft system adopts an outer ring rotating structure. When the main shaft size and bearing span are the same, the outer ring rotating structure has a stronger bearing capacity, which meets the use requirements of large MW units; the rotating shaft 2 adopts a double-disc shared reinforcing rib I11 structure, which makes the overall rigidity of the shaft system structure strong, simple in structure, light in weight, and economical. The transition between the fixed shaft 1 body and the flange disc structure adopts a concave structure 12 with multiple large R smooth arc transitions, and a transition ring 13 is set at the concave structure 12. On the basis of meeting the structural use requirements, the stress concentration factor of the fixed shaft 1 is greatly reduced, meeting the use requirements of large MW units.

[0037] The main shaft system of a wind turbine generator is an important component for converting wind energy into electrical energy. When the wind turbine generator set is working, the wind load is transmitted to the rotating shaft 2 through the blades and the hub 5, and then to the fixed shaft 1 and the main frame 4 through the bearing 3. The wind load drives the rotating parts of the generator to rotate, and completes the conversion of mechanical energy to electrical energy at the air gap of the generator. The rotating shaft 2 provides support for the rotating parts of the unit such as the hub 5 and the rotor bracket, and at the same time bears the effect of wind load; the fixed shaft 1 is connected to the main frame 4 to provide support for the stator bracket 6 and the bearing 3 of the generator; two single-row tapered roller bearings are located between the fixed shaft 1 and the rotating shaft 2, which ensures the rotation accuracy of the shaft and reduces the friction and wear between the rotating parts and the stationary parts of the unit. The main shaft system of a wind turbine generator not only bears the effect of wind load, but also provides support for various parts of the generator, and is an important part of the wind turbine set.

[0038] Example 2

[0039] The difference between this embodiment and the first embodiment is that, in this embodiment, the end surface of the shaft main body 9 of the fixed shaft 1 away from the disc flange 10 is provided with a bearing pressing ring 14 engaged with the end surface flange of the fixed shaft 1, and the rest of the structure is the same as that of the first embodiment.

[0040] In this embodiment, the bearing pressing ring 14 provides axial preload for the bearing to ensure safe and stable operation of the bearing.

[0041] Example 3

[0042] The difference between this embodiment and embodiment 1 is that, in this embodiment, Figure 3 As shown, the end surface of the rotating shaft 2 away from the disc II 8 is provided with a brake disc 15 engaged with the rotating shaft 2, and the bearing pressure ring 14 is engaged with a brake 16 matched with the brake disc 15. The rest of the structure is the same as that of embodiment 1.

[0043] In this embodiment, the brake disc 15 and the brake 16 are provided to realize the braking function of the shaft system, thereby realizing the braking of the wind turbine generator set.

[0044] Example 4

[0045] The present embodiment is different from the first embodiment in that, in the present embodiment, a reinforcing rib II for increasing rigidity is provided on the fixed-axis circular disc; the rest of the structure is the same as that of the first embodiment.

[0046] In this embodiment, reinforcing ribs II are provided on the fixed-axis disc to increase the rigidity of the fixed-axis disc and meet the rigidity requirement of the generator set.

[0047] Example 5

[0048] Compared with Example 1, the present embodiment is different in that, in the present embodiment, the bearings 3 are all single-row tapered roller bearings, the outer diameters of the two bearings 3 are greater than 3 meters, the two bearings 3 are of different sizes, and the difference in the outer diameters of the two bearings 3 is less than 100 mm, and the span of the bearings 3 is smaller than the outer diameter of any one of the bearings 3; the inner diameter of the bearing 3 on the side away from the fixed axis disc of the two bearings 3 is smaller than the inner diameter of the bearing 3 on the side close to the fixed axis disc, and the rest of the structure is the same as that of Example 1.

[0049] In this embodiment, the axial dimension of the entire shaft system is shortened by the structure of the bearing 3, the structure is compact and light, and the economy of the unit is improved; when the bearing 3 is assembled, the fixed axis disc side faces the ground, the downwind bearing 3 is installed first and moved axially to the transition ring 13 through the shaft end away from the axis disc side. The design of this size facilitates the installation of the bearing 3 and reduces the difficulty of assembly.

[0050] Example 6

[0051] The difference between this embodiment and embodiment 1 is that in this embodiment, wedge-shaped seals 17 for sealing bearing grease are provided at both ends of the rotating shaft 2, and the wedge-shaped seals 17 are installed between the fixed shaft 1 and the rotating shaft 2. The rest of the structure is the same as that of embodiment 1.

[0052] In this embodiment, when the bearing 3 is working, good lubrication must be ensured. By arranging a wedge-shaped seal to prevent the loss of grease of the bearing 3, good lubrication of the bearing 3 is guaranteed.

[0053] Example 7

[0054] Compared with Example 1, the present embodiment is different in that, in the present embodiment, a brake protective cover 18 is provided on the bearing pressure ring 14, a grease removal maintenance hole is provided on the fixed shaft 1, a waist-shaped hole for bearing 3 maintenance is provided along the circumferential direction of the rotating shaft 2, and an easily removable cover plate is provided on the waist-shaped hole; the rest of the structure is the same as that of Example 1.

[0055] In this embodiment, a brake protective cover 18 is provided to provide protection for the brake 16 and the brake disc 15 to prevent foreign matter from entering and causing damage to the brake components and the brake disc 15. The waist-shaped hole is provided at the oil chamber baffle of the rotating shaft 2. By providing a grease removal maintenance hole and a waist-shaped hole, maintenance of the shaft system is facilitated. An easily removable cover is provided on the waist-shaped hole for easy opening and closing during maintenance.

[0056] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A main shaft system of a wind turbine generator, characterized in that: The invention comprises a fixed shaft (1) engaged with a main frame (4), a rotating shaft (2) engaged with a wheel hub (5), and two bearings (3) for supporting the shaft system. The fixed shaft (1) comprises a shaft body (9) and a disc flange (10). The rotating shaft (2) is sleeved on the outside of the shaft body (9) of the fixed shaft (1). The rotating shaft (2) is provided with a disc I (7) and a disc II (8) on its outer sleeve. The disc II (8) is located at one end of the rotating shaft (2) close to the disc flange (10). The disc I (7) is located in the middle of the rotating shaft (2). A reinforcing rib I (11) is provided between the disk I (7) and the disk II (8) and passes through the two disks. The side of the disk I (7) not provided with the reinforcing rib I (11) is engaged with the hub (5). The end surface of the disk flange portion (10) of the fixed shaft (1) away from the shaft main body portion (9) is engaged with the main frame (4). Two bearings (3) are respectively provided on the inner circumferential surfaces at both ends of the rotating shaft (2). The outer circumferential surfaces of the bearings (3) are interference fit with the inner circumferential surfaces of the rotating shaft (2). The inner circumferential surfaces of the bearings (3) are respectively engaged with the shaft of the fixed shaft (1). The outer circumferential surfaces at both ends of the main body (9) are interference fit, and the outer circumferential surface of the disc flange part (10) of the fixed shaft (1) close to the shaft main body (9) is sleeved with a fixed shaft disc, and the fixed shaft disc is engaged with the stator bracket (6); an inner concave structure (12) is provided at the transition between the shaft main body (9) and the disc flange part (10) of the fixed shaft (1), and the inner surface of the inner concave structure (12) adopts multiple sections of circular arcs with an inner fillet R greater than 50°, and the multiple sections of circular arcs are smoothly transitioned, and a transition ring (13) is provided in the inner concave structure (12), and the transition ring (13) The axial direction extends to the bearing (3) outside the inner concave structure, the transition ring (13) and the bearing (3) are interference fit, the outer cylindrical surface of the transition ring (13) and the fixed shaft (1) are interference fit, and the inner cylindrical surface of the transition ring (13) and the fixed shaft (1) are clearance fit; the two bearings (3) are both single-row tapered roller bearings, the outer diameters of the two bearings (3) are greater than 3 meters, the two bearings (3) are of different sizes, and the difference in the outer diameters of the two bearings (3) is less than 100 mm, and the span of the bearings (3) is less than the outer diameter of any one of the bearings (3).

2. A main shaft system of a wind turbine generator according to claim 1, characterized in that: The end surface of the fixed shaft (1) shaft body (9) away from the disc flange (10) is provided with a bearing pressing ring (14) engaged with the end surface flange of the fixed shaft (1).

3. A main shaft system of a wind turbine generator according to claim 2, characterized in that: The end surface of the rotating shaft (2) away from the disc II (8) is provided with a brake disc (15) engaged with the rotating shaft (2), and the bearing pressure ring (14) is provided with a brake (16) matched with the brake disc (15).

4. A main shaft system of a wind turbine generator according to claim 3, characterized in that: The upper handle of the bearing pressing ring (14) is provided with a brake protection cover (18).

5. The main shaft system of a wind turbine generator according to claim 1, characterized in that: The fixed axis disc is provided with reinforcing ribs II for increasing rigidity.

6. The main shaft system of a wind turbine generator according to claim 1, characterized in that: Of the two bearings (3), the inner diameter of the bearing (3) on the side away from the fixed axis disc is smaller than the inner diameter of the bearing (3) on the side close to the fixed axis disc.

7. The main shaft system of a wind turbine generator according to claim 1, characterized in that: Wedge-shaped seals (17) for sealing bearing grease are provided at both ends of the rotating shaft (2), and the wedge-shaped seals (17) are installed between the fixed shaft (1) and the rotating shaft (2).

8. The main shaft system of a wind turbine generator according to claim 1, characterized in that: The fixed shaft (1) is provided with a grease removal maintenance hole, the rotating shaft (2) is provided with a waist-shaped hole for inspecting the bearing (3) along the circumferential direction, and an easily removable cover plate is provided on the waist-shaped hole.

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