A main shaft system for a large wind turbine generator set

Abstract

The present invention discloses a main shaft system of a large wind turbine generator set, which belongs to the field of wind power generation, including a wind turbine main shaft, a main shaft housing is provided on the wind turbine main shaft, a dynamic and static pressure sliding bearing is provided on the wind turbine main shaft, a main shaft shoulder is provided on the wind turbine main shaft, a main shaft housing is provided on the outside of the dynamic and static pressure sliding bearing, an oil inlet channel and a housing shoulder are provided on the main shaft housing, a thrust pad is provided between the main shaft shoulder and the housing shoulder, and the oil inlet channel is connected with the dynamic and static pressure sliding bearing and the thrust pad. The outer layer of the dynamic and static pressure sliding bearing is a first steel ring, the middle part is a first copper alloy layer, and the inner surface is a first friction layer and a coating. All bearings of the present invention are composite dynamic and static pressure bearings, which are composed of three parts. The outer layer is steel, which can increase the rigidity and strength of the entire bearing, and the copper alloy can reduce the elastic modulus, is easy to deform, and reduces the bearing eccentric load, and has an adaptive function. The use of a two-stage pressure control valve can select a suitable oil pressure according to the size of the wind speed to ensure that the bearing has a suitable bearing capacity.

Description

Technical Field

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

[0002] Wind turbines work outdoors all year round, with harsh working conditions, large temperature and humidity changes, and complex load conditions. Therefore, wind turbine bearings are required to have good impact resistance, sealing and lubricity, long life and high reliability. Wind turbine bearings are important supporting components of wind turbines and play a very important role in the life, performance and reliability of the entire unit.

[0003] The main sources of load on the main shaft in a wind turbine are the gravity load of the wind turbine blades and hub, the deadweight load of the main shaft, the support and thrust force of the main shaft bearing, the inertial load and aerodynamic load of the wind acting on the main shaft through the blades and hub, etc. Therefore, the main shaft needs to bear radial force and axial force generated by wind. In addition, due to the particularity of the working environment of the wind turbine, axial impact will also be generated with the sudden change of wind speed. The inner ring of the wind turbine main shaft bearing is installed with the wind turbine main shaft through an interference fit, and the outer ring of the bearing is fixed on the special support of the frame. The axial force is applied by the shoulder of the main shaft to the end face of the inner ring of the bearing.

[0004] In a running bearing, only a portion of the rollers are under load at the same time, and the area where these rollers are located is called the bearing load zone. The load borne by the bearing and the size of the running clearance will affect the load zone. If the load zone is too small, the rollers are prone to slipping during actual operation.

[0005] The speed of the wind turbine gearbox input shaft is generally 10-20 rpm. Due to the relatively low speed, it is often difficult to form an oil film on the input shaft bearing, which is also the planetary carrier support bearing.

[0006] As the unit capacity and main shaft diameter of wind turbines become larger and larger, and considering the cost-effectiveness of the units, the price of main shaft bearings is very high. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a main shaft system of a large wind turbine generator set.

[0008] The technical solution of the present invention is as follows: A large-scale wind turbine main shaft system includes a wind turbine main shaft and a main shaft housing, wherein the main shaft housing is arranged on the outside of the wind turbine main shaft, the wind turbine main shaft is provided with a main shaft shoulder, the main shaft housing is provided with a housing shoulder, dynamic and static pressure sliding bearings are provided between the wind turbine main shaft and the main shaft housing, the main shaft housing is provided with an oil inlet channel, the oil inlet channel is connected to the dynamic and static pressure sliding bearings, and end covers are provided at the ends of the main shaft housing and the wind turbine main shaft.

[0009] A dynamic and static thrust sliding bearing is arranged between the wind turbine main shaft and the main shaft housing, a thrust washer is arranged between the main shaft shoulder and the housing shoulder, the thrust washer is fixed on the housing shoulder through a pin shaft, and the oil inlet channel is connected to the thrust washer.

[0010] The dynamic and static pressure sliding bearing and the thrust static pressure sliding bearing are both divided into three layers, wherein the outer layer is a first steel ring, the middle part is a first copper alloy layer, and the inner surface is a first friction layer and a coating. The contact surface between the thrust static pressure sliding bearing and the main shaft shoulder is provided with a first friction layer and a coating. The dynamic and static pressure sliding bearing and the thrust static pressure sliding bearing are provided with a plurality of first oil inlet chambers and annular grooves, and the oil inlet chambers are interconnected through the annular grooves. One end of the first oil inlet chamber on the dynamic and static pressure sliding bearing is connected to the fitting clearance between the dynamic and static pressure sliding bearing and the wind turbine main shaft, and the other end is connected to the oil inlet channel. One end of the first oil inlet chamber on the thrust static pressure sliding bearing is connected to the fitting clearance between the thrust static pressure sliding bearing and the wind turbine main shaft, and the other end is connected to the oil inlet channel.

[0011] Two main shaft shoulders are provided on the main shaft housing, and the housing shoulder is located between the two main shaft shoulders. A thrust washer is respectively provided between the main shaft shoulder and the housing shoulder, and the two thrust washers are respectively located on both sides of the main shaft shoulder. The thrust washer is fixed to the housing shoulder through a pin shaft, and the oil inlet channel is connected to the thrust washer. There are two dynamic and static pressure sliding bearings between the wind turbine main shaft and the main shaft housing, which are symmetrically arranged on both sides of the housing shoulder.

[0012] The dynamic and static pressure sliding bearing is a split type, comprising an upper bearing and a lower bearing, and the upper bearing and the lower bearing are connected to each other through bolts and positioning pins.

[0013] The dynamic and static pressure sliding bearing is divided into three layers. The outer layer of the dynamic and static pressure sliding bearing is a first steel ring, the middle part is a first copper alloy layer, and the inner surface is a first friction layer and a coating. The dynamic and static pressure sliding bearing is provided with a first oil inlet cavity and an annular groove. One end of the first oil inlet cavity is connected to the matching clearance between the dynamic and static pressure sliding bearing and the wind turbine main shaft, and the other end is connected to the oil inlet channel.

[0014] The thrust washer is divided into three layers, the outer layer of the thrust washer is a second steel ring, the middle part is a second copper alloy layer, the inner surface is a second friction layer and a coating, and a second oil inlet cavity is provided on the thrust washer, and the second oil inlet cavity is connected to the oil inlet channel.

[0015] The contact surface between the thrust bearing and the main shaft shoulder is modified by a concave micro-arc shape.

[0016] The oil inlet passage is connected to the hydraulic control system, which includes an oil tank, an oil pump, a cooler, an oil filter, a secondary pressure control valve, a first overflow valve and a first lubricating oil outlet. The oil tank is connected to the oil pump, the oil pump is connected to the cooler, the cooler is connected to the oil filter, the oil filter is connected to the secondary pressure control valve, the secondary pressure control valve is connected to the first lubricating oil outlet, the first lubricating oil outlet is connected to the oil inlet passage, a first overflow valve is connected between the secondary pressure control valve and the first lubricating oil outlet, the secondary pressure control valve is connected to the second lubricating oil outlet, the second lubricating oil outlet is connected to the gear box, and a second overflow valve is connected between the secondary pressure control valve and the second lubricating oil outlet.

[0017] The front end of the wind turbine main shaft is connected with a propeller hub, the main shaft housing and the mounting bracket are integrated, the rear end of the wind turbine main shaft is connected to the planetary frame through bolts and pins, and the planetary frame is connected to the gear box.

[0018] The dynamic and static pressure sliding bearing and thrust bearing of the present invention are composite bearings composed of three parts. The outer layer is steel, which can increase the rigidity and strength of the entire bearing. The copper alloy can reduce the elastic modulus, facilitate elastic deformation, reduce the bearing eccentric load, and have an adaptive function. Compared with rolling bearings, the dynamic and static pressure sliding bearings are smaller in size and lower in cost. The secondary pressure control valve can control the generation of medium pressure and high pressure oil pressures, and can select the appropriate oil pressure according to the size of the wind speed. When the wind speed is low, medium pressure oil is used, and when the wind speed is high, high pressure oil is used to ensure that the bearing has a suitable bearing capacity. The bearing capacity of the dynamic and static pressure bearing is greater than that of the rolling bearing, and the installation size is smaller than that of the rolling bearing. The cost is lower than that of the rolling bearing, and the use of imported bearings can be avoided, so that the bearings are domestically produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] Figure 2 It is a schematic diagram of the structure of the present invention;

[0021] Figure 3 It is a schematic diagram of the structure of the present invention;

[0022] Figure 4 yes Figure 2 Side view of

[0023] Figure 5 It is a load diagram of an existing single dynamic and static pressure sliding bearing;

[0024] Figure 6 It is a schematic diagram of the load of the dynamic and static pressure sliding bearing of the present invention;

[0025] Figure 7 It is a structural schematic diagram of the thrust static pressure sliding bearing of the present invention;

[0026] Figure 8 It is a structural schematic diagram of the dynamic and static pressure sliding bearing of the present invention;

[0027] Fig. 9 It is a schematic diagram of the structure of the thrust washer;

[0028] Fig.10 It is the stress deformation diagram of the existing thrust washer;

[0029] Fig.11 It is a schematic diagram of the modification of the thrust pad of the present invention;

[0030] Fig.12 It is a schematic diagram of the structure of the integrated spindle housing;

[0031] Fig.13 It is a schematic diagram of the structure of the split spindle housing;

[0032] Fig.14 It is a schematic diagram of the structure of the split spindle housing;

[0033] Fig.15 It is a structural diagram of the hydraulic control system;

[0034] In the figure: 1-wind turbine main shaft, 2-main shaft housing, 3-dynamic and static pressure sliding bearing, 4-thrust pad, 5-planet carrier, 6-planet shaft, 7-gear box, 8-hub, 9-mounting bracket, 10-end cover, 11-oil inlet channel, 12-main shaft shoulder, 13-housing shoulder, 14-first steel ring, 15-first copper alloy layer, 16-first friction layer and first coating, 17-first oil inlet chamber, 18-second steel ring, 19-second copper alloy Gold layer, 20-second friction layer and second coating, 21-second oil inlet chamber, 22-oil tank, 23-oil pump, 24-cooler, 25-oil filter, 26-secondary pressure control valve, 27-first lubricating oil outlet, 28-first overflow valve, 29-second lubricating oil outlet, 30-second overflow valve, 31-thrust static pressure sliding bearing, 32-upper bearing, 33-lower bearing, 34-upper shell, 35-lower shell, 36-bolts. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings:

[0036] like Figure 1 , Figure 2 , Figure 4 , Figure 5As shown, a large-scale wind power generation main shaft system includes a wind power main shaft 1 and a main shaft housing 2, wherein the main shaft housing 2 is arranged on the outside of the wind power main shaft 1, the wind power main shaft 1 is provided with a main shaft shoulder 12, the main shaft housing 2 is provided with a housing shoulder 13, a dynamic and static pressure sliding bearing 3 is provided between the wind power main shaft 1 and the main shaft housing 2, an oil inlet channel 11 is provided on the main shaft housing 2, the oil inlet channel 11 is connected to the dynamic and static pressure sliding bearing 3, end covers 10 are provided at the ends of the main shaft housing 2 and the wind power main shaft 1, a thrust static pressure sliding bearing 31 is provided between the wind power main shaft 1 and the main shaft housing 2, a thrust washer 4 is provided between the main shaft shoulder 12 and the housing shoulder 13, the thrust washer 4 is fixed to the housing shoulder 13 by a pin, and the oil inlet channel 11 is connected to the thrust washer 4.

[0037] like Figure 7 , Figure 8 As shown, the dynamic and static pressure sliding bearing 3 and the thrust static pressure sliding bearing 31 are divided into three layers, wherein the outer layer is a first steel ring 14, the middle part is a first copper alloy layer 15, and the inner surface is a first friction layer and a coating 16. The contact surface between the dynamic and static pressure sliding bearing 3 and the main shaft shoulder 12 is provided with a first friction layer and a coating 16. The dynamic and static pressure sliding bearing 3 and the thrust static pressure sliding bearing 31 are provided with a first oil inlet chamber 17 and an annular groove. One end of the first oil inlet chamber 17 on the dynamic and static pressure sliding bearing 3 is connected to the fitting clearance between the dynamic and static pressure sliding bearing 3 and the wind turbine main shaft 1, and the other end is connected to the oil inlet channel 11. One end of the first oil inlet chamber 17 on the thrust static pressure sliding bearing 31 is connected to the fitting clearance between the thrust static pressure sliding bearing 31 and the wind turbine main shaft 1, and the other end is connected to the oil inlet channel 11. The wind turbine main shaft 1 is an integral hollow casting. Both ends of the wind turbine main shaft 1 are supported by dynamic and static thrust radial dynamic and static pressure sliding bearings and dynamic and static pressure radial sliding bearings, as well as low-speed thrust bearings to support radial and axial forces. The outer circle of the bearing is supported on the main shaft housing 2. The thrust bearing 4 is between the main shaft shoulder 12 and the main shaft housing shoulder 13. The gap between the thrust bearing 4 is determined by design calculations and wind loads. The input flange end of the wind turbine main shaft 1 is sealed with an end cover. Fig.12 As shown, the spindle housing 2 is of an integrated type.

[0038] The front end of the wind turbine main shaft 1 is connected to a hub 8, the main shaft housing 2 and the mounting bracket 9 are integrated, and the mounting bracket 9 is a circular flange. The rear end of the wind turbine main shaft 1 is connected to the planetary frame 5 through bolts 17 or pins (for semi-direct drive units), and the planetary frame 5 is provided with a planetary shaft 6, which is connected to a gear box 7, and the gear box 7 is connected to a generator. The rear end of the wind turbine main shaft 1 is connected to the generator flange (for direct drive units).

[0039] like Figure 1 , Figure 3 , Figure 4 , Figure 5 As shown, a large-scale wind power generation main shaft system includes a wind power main shaft 1 and a main shaft housing 2, wherein the main shaft housing 2 is arranged outside the wind power main shaft 1, the wind power main shaft 1 is provided with a main shaft shoulder 12, the main shaft housing 2 is provided with a housing shoulder 13, a dynamic and static pressure sliding bearing 3 is provided between the wind power main shaft 1 and the main shaft housing 2, an oil inlet channel 11 is provided on the main shaft housing 2, and the oil inlet channel 11 is connected to the dynamic and static pressure sliding bearing 3, and the ends of the main shaft housing 2 and the wind power main shaft 1 are provided with end covers 10, the Two main shaft shoulders 12 are arranged on the main shaft housing 2, and the housing shoulder 13 is located between the two main shaft shoulders 12. A thrust washer 4 is respectively arranged between the main shaft shoulder 12 and the housing shoulder 13, and the two thrust washer 4 are respectively located on both sides of the main shaft shoulder 13. The thrust washer 4 is fixed on the housing shoulder 13 by a pin shaft, and the oil inlet channel 11 is connected to the thrust washer 4. There are two dynamic and static pressure sliding bearings 3 between the wind turbine main shaft 1 and the main shaft housing 2, which are respectively arranged on both sides of the housing shoulder 13 symmetrically. The wind turbine main shaft 1 is an integral hollow casting, and both ends of the wind turbine main shaft 1 are supported by dynamic and static pressure radial sliding bearings and low-speed thrust washer to support radial force and axial force. The outer circle of the bearing is supported on the main shaft housing 2, and the thrust washer 4 is between the main shaft shoulder 12 and the housing shoulder 13. The thrust washer gap is determined by design calculation and wind load; the input flange end of the wind turbine main shaft is sealed with an end cover. The spindle housing 2 is an integrated type. When assembling, first install the dynamic and static pressure sliding bearing on the left side, which is a split type, then install the thrust pad, then install the spindle housing, and finally install the dynamic and static pressure sliding bearing and the planet carrier on the right side in sequence, which is an integrated type. As shown in Figure 13, the spindle housing 2 is a split type, including an upper housing 34 and a lower housing 35, which are connected to each other by bolts, and the split spindle housing can ensure the assembly of the spindle housing 2.

[0040] The front end of the wind turbine main shaft 1 is connected to a hub 8, the main shaft housing 2 and the mounting bracket 9 are integrated, and the mounting bracket 9 is a circular flange. The rear end of the wind turbine main shaft 1 is connected to the planetary frame 5 through bolts 17 or pins (for semi-direct drive units), and the planetary frame 5 is provided with a planetary shaft 6, which is connected to a gear box 7, and the gear box 7 is connected to a generator. The rear end of the wind turbine main shaft 1 is connected to the generator flange (for direct drive units).

[0041] like Figure 7As shown, the thrust static pressure sliding bearing 31 is divided into three layers. The outer layer of the thrust static pressure sliding bearing 31 is the first steel ring 14, the middle part is the first copper alloy layer 15, and the inner surface is the first friction layer and coating 16. The first friction layer and coating 16 are provided on the contact surface between the thrust static pressure sliding bearing 31 and the main shaft shoulder 12. The friction layer is made of friction material, such as babbitt alloy, polytetrafluoroethylene, composite material, etc.; the coating is a coating that increases friction performance, such as molybdenum-based materials (molybdenum disulfide), polytetrafluoroethylene, etc., which are used to prevent wear caused by excessive friction when the oil film is too thin, or when the hydraulic system fails, it can play a role in protecting the friction layer. The specific scheme of the inner surface of the thrust static pressure sliding bearing 31 can be: 1. Aluminum-zinc alloy is the friction material, molybdenum-based material is the coating or polytetrafluoroethylene is the coating; 2. Babbitt alloy is the friction material, and polytetrafluoroethylene is the coating. The outer part of the bearing is made of steel to increase the rigidity and strength of the entire bearing. The copper alloy is used to reduce the elastic modulus, facilitate elastic deformation, reduce the bearing load, and have an adaptive function.

[0042] like Figure 8 As shown, the dynamic and static pressure sliding bearing 3 is divided into three layers, the outer layer of the dynamic and static pressure sliding bearing 3 is the first steel ring 14, the middle part is the first copper alloy layer 15, and the inner surface is the first friction layer and coating 16. The friction layer is made of friction material, such as babbitt alloy, polytetrafluoroethylene, composite material, etc.; the coating is a coating that increases friction performance, such as molybdenum-based materials (molybdenum disulfide), polytetrafluoroethylene, etc., which is used to prevent wear caused by excessive friction when the oil film is too thin, or when the hydraulic system fails, it can play a role in protecting the friction layer. The specific scheme of the inner surface of the dynamic and static pressure sliding bearing 3 can be: 1. Aluminum-zinc alloy is the friction material, molybdenum-based material is the coating or polytetrafluoroethylene is the coating; 2. Babbitt alloy is the friction material, and polytetrafluoroethylene is the coating. The outer part of the bearing is steel to increase the rigidity and strength of the entire bearing, and the copper alloy is to reduce the elastic modulus, easy elastic deformation, reduce the bearing load, and have an adaptive function.

[0043] The static and dynamic sliding bearing 3 is provided with a plurality of first oil inlet chambers and annular grooves, and the oil inlet chambers are interconnected through the annular grooves. One end of the first oil inlet chamber is connected to the matching clearance between the static and dynamic sliding bearing 3 and the wind turbine main shaft 1, and the other end is connected to the oil inlet channel 11. The static and dynamic sliding bearing 3 adopts a low-speed static and dynamic radial static and dynamic sliding bearing, and has a plurality of oil inlet chambers, which can cope with bending moments and forces in different directions. Because of the uncertainty of wind direction, the size and direction of the load are also uncertain, and medium oil pressure is used at high wind speed and medium oil pressure is used at low wind speed.

[0044] like Figure 7-Figure 9As shown, the thrust washer 4 adopts a cylindrical low-speed dynamic and static pressure thrust washer, and the thrust washer 4 is divided into three layers. The outer layer of the thrust washer 4 is a second steel ring 18, the middle part is a second copper alloy layer 19, and the inner surface is a second friction layer and a coating 20. The thrust washer 4 is provided with a second oil inlet cavity 21, and the second oil inlet cavity 21 is connected to the oil inlet channel 11. Steel can increase the rigidity and strength of the thrust washer 4, and the copper alloy can reduce the elastic modulus, facilitate elastic deformation, reduce eccentric load, have adaptive function, and have better bearing capacity. The existing thrust washer 4 is usually made of steel, with poor adaptive ability and weak bearing capacity.

[0045] The contact surface between the thrust pad 4 and the spindle shoulder 12 is modified by a concave micro-arc shape. Fig.10 As shown in the figure, when the thrust washer body is made entirely of steel, during operation, under static pressure, due to the relatively small fulcrum area, the thrust washer working surface is convex, that is, high in the middle and low on both sides, high-pressure oil is easy to leak, oil film pressure is not easy to establish, and energy consumption is also large. Fig.11 As shown in the figure, when the thrust washer body is made of copper alloy and steel composite, when working, under static pressure, due to the relatively large pressure in the middle and low pressure around, the elastic modulus of the copper alloy is low, the middle part is relatively deformed, and the surrounding parts are relatively deformed; at the same time, the contact surface is modified by a concave micro-arc. Then the thrust washer working surface is concave, that is, high in the middle and low on both sides, high-pressure oil is not easy to leak, oil film pressure is easy to establish, and energy consumption is also small.

[0046] like Fig.15As shown, the oil inlet passage 11 is connected to the hydraulic control system, which includes an oil tank 22, an oil pump 23, a cooler 24, an oil filter 25, a secondary pressure control valve 26 and a lubricating oil outlet 27. The oil tank 22 is connected to the oil pump 23, the oil pump 23 is connected to the cooler 24, the cooler 24 is connected to the oil filter 25, the oil filter 25 is connected to the secondary pressure control valve 26, the secondary pressure control valve 26 is connected to the lubricating oil outlet 27, the lubricating oil outlet 27 is connected to the oil inlet passage 11, and an overflow valve 28 is connected between the secondary pressure control valve 26 and the lubricating oil outlet 27. The hydraulic control system can use the wind power gearbox as the oil pool, or an external oil tank, a high-pressure gear pump as the oil pump, an air-cooled or water-cooled cooler, a conventional filter, and an electronically controlled secondary pressure control valve that complies with wind power standards. The secondary pressure control valve controls two oil pressures (high pressure and medium pressure), and produces a high-pressure oil and a medium-pressure oil at the oil inlet of the control valve, which are used to provide dynamic and static pressure bearings when the wind turbine is started or working; the bearings are lubricated with high-pressure oil at high wind speeds and with medium-pressure oil at low wind speeds. Each lubricating oil port at the oil outlet of the control valve is equipped with a throttling and overflow valve to produce a low-pressure oil to lubricate the bearings and gears of the gearbox when the unit is operating normally. When the wind turbine is affected by high wind speed, the secondary pressure control valve 26 will generate high-pressure oil, which will enter the first oil inlet chamber 17 of the dynamic and static pressure sliding bearing 3 and the second oil inlet chamber 21 of the thrust washer 4 through the oil inlet channel 11, and then enter the dynamic and static pressure sliding bearing and the wind turbine main shaft 1, and the thrust bearing 4 and the wind turbine main shaft 1 to form an oil film to play the role of impact resistance and lubrication. When the wind turbine is affected by low wind speed, the secondary pressure control valve 20 will generate medium-pressure oil, so that the matching clearance between the outer ring of the bearing and the inner ring of the bearing is of appropriate size, reducing energy consumption. The overflow valve 28 generates low-pressure oil to lubricate the bearings and gears of the gearbox when the unit is operating normally.

Claims

1. A main shaft system of a large wind turbine generator set, comprising a wind turbine main shaft (1) and a main shaft housing (2), characterized in that: The main shaft housing (2) is arranged outside the wind turbine main shaft (1); the wind turbine main shaft (1) is provided with a main shaft shoulder (12); the main shaft housing (2) is provided with a housing shoulder (13); a dynamic and static pressure sliding bearing (3) is provided between the wind turbine main shaft (1) and the main shaft housing (2); an oil inlet passage (11) is provided on the main shaft housing (2); the oil inlet passage (11) is connected to the dynamic and static pressure sliding bearing (3); end covers (10) are provided at the ends of the main shaft housing (2) and the wind turbine main shaft (1); a thrust static pressure sliding bearing (31) is provided between the wind turbine main shaft (1) and the main shaft housing (2); the dynamic and static pressure sliding bearing (3) and the thrust static pressure sliding bearing (31) are respectively arranged on both sides of the housing shoulder (13); A thrust washer (4) is provided between the main shaft shoulder (12) and the housing shoulder (13), and the thrust washer (4) is fixed to the housing shoulder (13) by a pin shaft. The oil inlet passage (11) is connected to the thrust washer (4). The dynamic and static pressure sliding bearing (3) and the thrust and static pressure sliding bearing (31) are both divided into three layers, wherein the outer layer is a first steel ring (14), the middle part is a first copper alloy layer (15), and the inner surface is a first friction layer and a coating (16). The first friction layer and the coating (16) are provided on the contact surface between the thrust and static pressure sliding bearing (31) and the main shaft shoulder (12). The dynamic and static pressure sliding bearing (3) and the thrust and static pressure sliding bearing (31) are provided with a plurality of first oil inlet chambers (17) and annular grooves. One end of the first oil inlet chamber (17) on the bearing (3) is connected to the matching clearance between the dynamic and static pressure sliding bearing (3) and the wind turbine main shaft (1), and the other end is connected to the oil inlet passage (11); one end of the first oil inlet chamber (17) on the thrust static pressure sliding bearing (31) is connected to the matching clearance between the thrust static pressure sliding bearing (31) and the wind turbine main shaft (1), and the other end is connected to the oil inlet passage (11); the oil inlet passage (11) is connected to a hydraulic control system, and the hydraulic control system comprises an oil tank (22), an oil pump (23), a cooler (24), an oil filter (25), a secondary pressure control valve (26), a first overflow valve (28) and a first lubricating oil outlet (27); the oil tank (22) and the oil pump (23) are connected to each other. The oil pump (23) is connected to a cooler (24), the cooler (24) is connected to an oil filter (25), the oil filter (25) is connected to a secondary pressure control valve (26), the secondary pressure control valve (26) is connected to a first lubricating oil outlet (27), the first lubricating oil outlet (27) is connected to an oil inlet passage (11), a first overflow valve (28) is connected between the secondary pressure control valve (26) and the first lubricating oil outlet (27), the secondary pressure control valve (26) is connected to a second lubricating oil outlet (29), the second lubricating oil outlet (29) is connected to a gear box (7), and a second overflow valve (30) is connected between the secondary pressure control valve (26) and the second lubricating oil outlet (29),The dynamic and static pressure sliding bearing (3) is of a split type, comprising an upper bearing (32) and a lower bearing (33), and the upper bearing (32) and the lower bearing (33) are connected to each other by bolts.

2. A main shaft system for a large wind turbine generator set as claimed in claim 1, characterized in that: The thrust washer (4) is divided into three layers. The outer layer of the thrust washer (4) is a second steel ring (18), the middle part is a second copper alloy layer (19), and the inner surface is a second friction layer and a coating (20). The thrust washer (4) is provided with a second oil inlet cavity (21), and the second oil inlet cavity (21) is connected to the oil inlet channel (11).

3. A main shaft system for a large wind turbine generator set as claimed in claim 2, characterized in that: The contact surface between the thrust washer (4) and the main shaft shoulder (12) is modified by a concave micro-arc shape.

4. A main shaft system for a large wind turbine generator set as claimed in claim 1, characterized in that: The front end of the wind turbine main shaft (1) is connected to a propeller hub (8), the main shaft housing (2) and the mounting bracket (9) are integrated, the rear end of the wind turbine main shaft (1) is connected to a planetary frame (5) via bolts and pins, and the planetary frame (5) is connected to a gear box (7).

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