A wind power generation main shaft system

Abstract

The present invention discloses a wind power generation main shaft system, which belongs to the field of wind power generation, and comprises a wind power main shaft, wherein the wind power main shaft is provided with a main shaft housing, and a conical dynamic and static pressure sliding bearing is provided between the main shaft housing and the wind power main shaft, and an oil inlet channel is provided on the main shaft housing, and the oil inlet channel is connected to the conical dynamic and static pressure sliding bearing. The outer layer of the outer ring of the conical static pressure sliding bearing is a steel ring, the middle part is a copper alloy layer, and the inner layer is a friction coating. The hydraulic system bearing oil of the present invention has two pressures, medium pressure and high pressure. The outer ring of the conical dynamic and static pressure bearing of the present invention is composed of three parts. The outer ring of the bearing is steel, which can increase the rigidity and strength of the entire bearing, and 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, conical dynamic and static pressure sliding bearings are smaller in size and lower in cost.

Description

Technical Field

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

[0008] The technical solution of the present invention is as follows: A wind power generation main shaft system includes a wind turbine main shaft, the wind turbine main shaft outer casing is provided with a main shaft housing, a conical dynamic and static pressure sliding bearing is provided between the main shaft housing and the wind turbine main shaft, an oil inlet channel is provided on the main shaft housing, and the oil inlet channel is connected to the conical dynamic and static pressure sliding bearing.

[0009] The tapered dynamic and static pressure sliding bearing is divided into a bearing inner ring and a bearing outer ring. The outer layer of the bearing outer ring is a steel ring, the middle part is a copper alloy layer, and the inner surface is a friction layer and a coating.

[0010] The tapered dynamic and static pressure sliding bearing is provided with one or more oil inlet chambers and intermediate ring grooves, each oil inlet chamber is connected by the intermediate ring groove, and the oil inlet chamber is connected with the matching clearance between the inner ring and the outer ring of the tapered dynamic and static pressure sliding bearing.

[0011] A disc spring is arranged between the conical dynamic and static pressure sliding bearing and the main shaft housing.

[0012] The outer ring friction surface of the tapered sliding bearing is modified to be concave and slightly arc-shaped.

[0013] The main shaft housing and the ends of the wind turbine main shaft are sealed by an end cover.

[0014] 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, and a first overflow valve is connected between the secondary pressure control valve and the first lubricating oil outlet.

[0015] The secondary pressure control valve is connected to a second lubricating oil outlet, the second lubricating oil outlet is connected to a gear box, and a second overflow valve is connected between the secondary pressure control valve and the second lubricating oil outlet.

[0016] The front end of the wind turbine main shaft is connected with a propeller hub, the main shaft housing is integrated with the mounting bracket, the rear end of the wind turbine main shaft is connected to the planetary frame through bolts and pins, the planetary frame is provided with a planetary shaft, and the planetary shaft is connected to the gear box.

[0017] The bearing capacity of the oil film of the tapered dynamic and static pressure sliding bearing meets the following requirements:

[0018] P=F 2 =F+F 1 ,

[0019] P 1 =Psinβ,

[0020] P 2 =Pcosβ,

[0021] P is the bearing capacity of the oil film of the tapered dynamic and static pressure sliding bearing,

[0022] P 1 is the axial force of the oil film of the tapered hydrostatic sliding bearing,

[0023] P 2 is the radial force of the oil film of the tapered hydrostatic sliding bearing,

[0024] F is the static pressure,

[0025] F 1 is the bearing capacity of the tapered hydrodynamic sliding bearing,

[0026] F 2 is the bearing capacity of the oil film of the tapered hydrostatic sliding bearing,

[0027]

[0028] Where: L is the bearing width; A is the correction factor, A = A 1 A 2 ; A 1 A is the bearing pressure end leakage coefficient, 0.9≤A 1 ≤1.0; A 2 is the bearing elastic deformation correction coefficient, A 2 =1.0; Ψ=e / δ is the relative eccentricity of the bearing; ω is the pressure amplitude, μ is the dynamic viscosity.

[0029] The outer ring of the tapered dynamic and static pressure bearing used in the present invention is composed of three parts. The outer ring of the bearing is steel, which can increase the rigidity and strength of the entire bearing. The copper alloy can reduce the elastic modulus, easily deform elastically, reduce the bearing load, and have an adaptive function. The outer ring friction surface of the bearing adopts a concave micro-arc shape, and the oil film is not easy to leak. Compared with rolling bearings, the tapered dynamic and static pressure bearing is smaller in size and lower in cost. The secondary pressure control valve can control the generation of medium pressure and high pressure oil pressure, and can select the appropriate oil pressure according to the wind speed to ensure that the bearing has a suitable bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the present invention;

[0032] Figure 3 It is a schematic diagram of the structure of the present invention;

[0033] Figure 4 yes Figure 3 Side view of;

[0034] Figure 5 It is a schematic diagram of the structure of a tapered dynamic and static pressure sliding bearing;

[0035] Figure 6 It is a schematic diagram of the structure of the outer ring of a tapered dynamic and static pressure sliding bearing;

[0036] Figure 7 It is a schematic diagram of the structure of the outer ring of a tapered dynamic and static pressure sliding bearing;

[0037] Figure 8 It is a schematic diagram of the structure of the inner ring of a tapered dynamic and static pressure sliding bearing;

[0038] Fig. 9 It is a schematic diagram of the structure of the friction surface between the outer ring and the inner ring of a tapered dynamic and static pressure sliding bearing;

[0039] Fig.10 It is a structural diagram of the hydraulic control system;

[0040] Fig.11 It is a schematic diagram of the pressure curve of the oil film of a conical dynamic and static pressure sliding bearing;

[0041] In the figure: 1-wind turbine main shaft, 2-main shaft housing, 3-conical dynamic and static pressure sliding bearing, 4-disc spring, 5-planet carrier, 6-planet shaft, 7-gear box, 8-hub, 9-mounting bracket, 10-end cover, 11-oil inlet channel, 12-steel ring, 13-copper alloy layer, 14-friction layer and coating, 15-bearing inner ring, 16-oil tank, 17-oil pump, 18-cooler, 19-oil filter, 20-secondary pressure control valve, 21-first lubricating oil outlet, 22-first overflow valve, 23-oil inlet chamber, 24-second lubricating oil outlet, 25-second overflow valve, 26-outer ring friction surface, 27-inner ring friction surface, 28-bolt. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with the accompanying drawings:

[0043] like Figure 1-4As shown, a wind power generation main shaft system includes a wind power main shaft 1, wherein the wind power main shaft 1 is provided with a main shaft housing 2, and two conical dynamic and static pressure sliding bearings 3 are provided between the main shaft housing 2 and the wind power main shaft 1, and an oil inlet channel 11 is provided on the main shaft housing 2, and the oil inlet channel 11 is connected to the conical dynamic and static pressure sliding bearings 3. The ends of the main shaft housing 2 and the wind power main shaft 1 are sealed with an end cover 10. A disc spring 4 can be provided between the conical dynamic and static pressure sliding bearings 3 and the main shaft housing 2, and the disc spring 4 plays a role in automatically adjusting the bearing oil gap. The front end of the wind power main shaft 1 is connected with a hub 8, and the main shaft housing 2 is integrated with a mounting bracket 9, and the mounting bracket 9 is a circular flange. The rear end of the wind power main shaft 1 is connected to a planetary frame 5 (for a semi-direct drive unit) through a bolt 28 or a pin shaft, and a planetary shaft 6 is provided on the planetary frame 5, and the planetary shaft 6 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). During assembly, first install the left conical dynamic and static pressure sliding bearing 3 on the wind turbine main shaft 1, then install the main shaft housing 2, then install the right conical dynamic and static pressure sliding bearing 3, and finally install the planet carrier 5. The wind turbine main shaft 1 is a hollow short shaft cast from high-strength ductile iron or high-strength alloy steel, with a large diameter, light weight, and high rigidity. Both ends of the wind turbine main shaft 1 are supported by conical dynamic and static pressure sliding bearings, the outer circle of the bearing is supported on the main shaft housing, and there are disc springs 4 for pre-tightening and vibration reduction. The bearing clearance is determined by design calculations and wind loads.

[0044] like Figure 5-9 As shown, the conical dynamic and static pressure sliding bearing 3 is a low-speed conical dynamic and static pressure sliding bearing. The conical dynamic and static pressure sliding bearing 3 is divided into a bearing inner ring and a bearing outer ring. The bearing inner ring and the bearing outer ring are used in conjunction with each other. The outer layer of the bearing outer ring is a steel ring 12, the middle part is a copper alloy layer 13, and the inner surface is a friction layer and a coating 14. 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 bearing inner ring is made of alloy steel. The specific scheme of the inner surface of the bearing outer ring 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 ring of the bearing is made of steel to increase the rigidity and strength of the entire bearing, and the copper alloy is used to reduce the elastic modulus, facilitate elastic deformation, reduce the bearing load, and have adaptive functions. The tapered dynamic and static pressure bearing can withstand axial and radial forces.

[0045] One or more oil inlet chambers 15 and intermediate ring grooves are provided on the outer ring of the tapered dynamic and static pressure sliding bearing 3. The oil inlet chambers 15 are interconnected through the intermediate ring grooves. The oil inlet chambers 15 are connected to the matching clearance between the inner ring and the outer ring of the tapered dynamic and static pressure sliding bearing 3.

[0046] Advantages of using a composite bearing structure: relative to radial cylindrical bearings, when the main shaft is subjected to bending moment, the cylindrical bearing is subjected to eccentric load, the gap between the main shaft and the bearing is larger on one side and smaller on the other side, high-pressure oil is easy to leak, oil film pressure is not easy to establish, and energy consumption is also high; the middle layer of the bearing outer ring of the present invention is copper alloy, which has a relatively small elastic modulus and is easy to deform elastically, thereby reducing the eccentric load of the bearing.

[0047] The outer ring friction surface 26 of the tapered sliding bearing 3 is modified by a concave micro-arc shape. The arc shape is designed according to the optimal value of the bearing deformation. The bearing will deform after being loaded, and the internal oil film also needs space. After the bearing is loaded and deformed, it is just in a straight line, and the internal oil film is not easy to leak out.

[0048] Large rolling bearings are very expensive, while hydrostatic sliding bearings are much cheaper. Using tapered hydrostatic sliding bearings can save space and are smaller than rolling bearings, making the overall volume of the main shaft system small. They can share the same hydraulic system with the wind turbine gearbox.

[0049] like Fig.10As shown, the oil inlet passage 11 is connected to the hydraulic control system, and the hydraulic control system includes an oil tank 16, an oil pump 17, a cooler 18, an oil filter 19, a secondary pressure control valve 20, a first overflow valve 22 and a first lubricating oil outlet 21. The oil tank 16 is connected to the oil pump 17, the oil pump 17 is connected to the cooler 18, the cooler 18 is connected to the oil filter 19, the oil filter 19 is connected to the secondary pressure control valve 20, the secondary pressure control valve 20 is connected to the first lubricating oil outlet 21, the first lubricating oil outlet 21 is connected to the oil inlet passage 11, and a first overflow valve 22 is connected between the secondary pressure control valve 20 and the first lubricating oil outlet 21. The hydraulic control system can use the wind turbine 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, and the filter is the same as the conventional wind turbine filter. The secondary pressure control valve is electronically controlled and meets the wind turbine standard. 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 the bearings are lubricated with medium-pressure oil at low wind speeds. Each lubricating oil port at the oil outlet of the control valve is throttled and has a relief 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 20 will produce high-pressure oil to enter the oil inlet cavity of the conical dynamic and static pressure sliding bearing 3 through the oil inlet channel 11, and then enter the outer ring of the bearing and the inner ring of the bearing to form an oil film to play a role in 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 clearance between the outer ring of the bearing and the inner ring of the bearing is of appropriate size, which can prevent slipping during operation and reduce energy consumption. The secondary pressure control valve 20 is connected to the second lubricating oil outlet 24, and the second lubricating oil outlet 24 is connected to the gear box 7. A second overflow valve 25 is connected between the secondary pressure control valve 20 and the second lubricating oil outlet 24. The second overflow valve 25 can also generate low-pressure oil to lubricate the bearings and gears of the gear box 7 when the unit is operating normally.

[0050] like Fig.11 As shown, the bearing capacity of the oil film of the tapered dynamic and static pressure sliding bearing 3 satisfies:

[0051] P=F 2 =F+F 1 ,

[0052] P 1 =Psinβ,

[0053] P 2 =Pcosβ,

[0054] P is the bearing capacity of the oil film of the tapered dynamic and static pressure sliding bearing,

[0055] P 1 is the axial force of the oil film of the tapered hydrostatic sliding bearing,

[0056] P 2 is the radial force of the oil film of the tapered hydrostatic sliding bearing,

[0057] F is the static pressure,

[0058] F 1 is the bearing capacity of the tapered hydrodynamic sliding bearing,

[0059] F 2 is the bearing capacity of the oil film of the tapered hydrostatic sliding bearing,

[0060]

[0061] Where: L is the bearing width; A is the correction factor, A = A 1 A 2 ; A 1 A is the bearing pressure end leakage coefficient, 0.9≤A 1 ≤1.0; A 2 is the bearing elastic deformation correction coefficient, A 2 =1.0; Ψ=e / δ is the relative eccentricity of the bearing; ω is the pressure amplitude, μ is the dynamic viscosity.

Claims

1. A wind power generation main shaft system, comprising a wind power generation main shaft (1), Features: The wind turbine main shaft (1) is provided with a main shaft housing (2) on its outer shell, a conical dynamic and static pressure sliding bearing (3) is provided between the main shaft housing (2) and the wind turbine main shaft (1), an oil inlet passage (11) is provided on the main shaft housing (2), the oil inlet passage (11) is connected to the conical dynamic and static pressure sliding bearing (3), the conical dynamic and static pressure sliding bearing (3) is divided into a bearing inner ring and a bearing outer ring, the outer layer of the bearing outer ring is a steel ring (12), the middle part is a copper alloy layer (13), and the inner surface is a friction layer and a coating (1 4), an oil inlet cavity (23) and an intermediate ring groove are provided on the bearing outer ring of the tapered dynamic and static pressure sliding bearing (3), the oil inlet cavity (23) and the intermediate ring groove are communicated, the oil inlet cavity (23) is communicated with the matching clearance between the bearing inner ring and the bearing outer ring of the tapered dynamic and static pressure sliding bearing (3), the oil inlet passage (11) is connected to a hydraulic control system, the hydraulic control system comprises an oil tank (16), an oil pump (17), a cooler (18), an oil filter (19), a secondary pressure control valve (20), a relief valve (22) and a first lubricating oil outlet (21), the oil tank (16) is connected to an oil pump (17), the oil pump (17) is connected to a cooler (18), the cooler (18) is connected to an oil filter (19), the oil filter (19) is connected to a secondary pressure control valve (20), the secondary pressure control valve (20) is connected to the first lubricating oil outlet (21), the first lubricating oil outlet (21) is connected to the oil inlet passage (11), the secondary pressure control valve (20) is connected to the first A first overflow valve (22) is connected between the first lubricating oil outlet (21), the second pressure control valve (20) can control the generation of two oil pressures, medium pressure and high pressure, the second pressure control valve (20) is connected to the second lubricating oil outlet (24), the second lubricating oil outlet (24) is connected to the gear box (7), a second overflow valve (25) is connected between the second pressure control valve (20) and the second lubricating oil outlet (24), the high pressure oil is used to lubricate the bearing at high wind speed, and the medium pressure oil is used to lubricate the bearing at low wind speed.

2. A wind power generation main shaft system as claimed in claim 1, Features: A disc spring (4) is provided between the conical dynamic and static pressure sliding bearing (3) and the main shaft housing (2).

3. A wind power generation main shaft system as claimed in claim 1, Features: The outer ring friction surface (26) of the tapered dynamic and static pressure sliding bearing (3) is modified by a concave micro-arc shape.

4. A wind power generation main shaft system as claimed in claim 1, Features: End covers (10) are provided at the ends of the main shaft housing (2) and the wind turbine main shaft (1).

5. A wind power generation main shaft system as claimed in claim 1, Features: 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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