A wind turbine beam-shaft separated main load-bearing structure

Abstract

This utility model discloses a wind turbine beam-shaft separated main load-bearing structure. This structure creatively distinguishes between a fixed load-bearing system and a rotary torque transmission system. The fixed load-bearing system, with a fixed load-bearing beam as its core, supports the hub through load-bearing connecting bearings and is specifically responsible for bearing and transmitting all non-torsional loads of the wind turbine to the lower platform. The rotary torque transmission system, with a rotary transmission main shaft as its core, is linked to the hub through a speed-increasing transmission device and is specifically responsible for transmitting the rotational torque of the wind turbine. The two systems are completely independent in mechanical structure and have no direct connection, achieving complete decoupling of load-bearing and torque transmission functions. This utility model fundamentally optimizes the stress state of key load-bearing components, significantly reduces stress concentration, greatly improves fatigue resistance and overall reliability, and at the same time helps to achieve structural lightweighting and reduce manufacturing and maintenance costs.

Description

Technical Field

[0001] This utility model belongs to the field of wind turbine generator structure technology, specifically relating to a structural design for the main load-bearing and transmission system of a horizontal axis wind turbine generator, and in particular a mechanical device for structurally decoupling, dividing the load-bearing and transmission of the complex load and rotational torque borne by the wind turbine. Background Technology

[0002] Traditional mainstream wind turbine generators generally adopt a centralized drivetrain layout of main shaft-bearing-gearbox or main shaft-generator. The core load-bearing and torsion-transmitting component is a single, continuous rotating main shaft. The front end of this main shaft supports the hub via bearings, bearing all aerodynamic, gravitational, and inertial loads from the wind turbine; simultaneously, the main shaft is responsible for transmitting the rotational kinetic energy of the wind turbine backward. This highly integrated design results in an extremely complex stress state for the main shaft, subjecting it to combined tensile, compressive, bending, torsional, and shear forces. This leads to a series of inherent defects: to meet the requirements of combined strength and stiffness, the main shaft has a large diameter and heavy weight, increasing the overall weight and cost of the unit; severe stress concentrations exist at the connections between the main shaft and the hub (such as shaft shoulders and locking threads) and at the connections with the gearbox / generator (such as splines), becoming initiation points for fatigue cracks; the main shaft is subjected to alternating bending stress during rotation, and its fatigue life becomes a key bottleneck restricting the reliability and service life of the unit. Therefore, the industry urgently needs a new type of main load-bearing structure that can fundamentally decouple load and torque and optimize the stress state of key components. Utility Model Content

[0003] This invention overcomes the shortcomings of existing technologies and provides a wind turbine beam-shaft separated main load-bearing structure. It aims to completely solve the problems of poor composite stress, significant stress concentration, limited fatigue life, and bulky structure of traditional integrated main shafts by constructing a static load-bearing system and a dynamic torsion transmission system that are physically and functionally independent.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a wind turbine beam-shaft separated main load-bearing structure, including a lower platform, a fixed load-bearing beam, a rotary transmission main shaft, a hub, a speed-increasing transmission device, a load-bearing connecting bearing, and a platform connecting component.

[0005] This utility model uses the fixed load-bearing beam as its core. The beam is a large, hollow, thin-walled steel structure, preferably with a circular or box-shaped variable cross-section design, and is fixedly arranged along the rotation axis of the wind turbine. The rear root of the beam is fixedly connected to the lower platform via the platform connecting member. This connection method allows for minor centering adjustments of the beam under load, avoiding additional bending moments. The inner ring of the load-bearing connecting bearing is precisely fitted onto the outer cylindrical surface of the front end of the beam. This bearing is preferably a combined bearing capable of simultaneously withstanding large radial forces, bidirectional axial forces, and overturning moments, such as a double-row tapered roller bearing or a three-row cylindrical roller combined bearing.

[0006] The main shaft runs through the fixed load-bearing beam, and its front end is connected to the power input end via the speed-increasing transmission device (preferably a single-stage planetary gear speed-increasing machine). The housing of the speed-increasing transmission device is rigidly connected to the side or rear end face of the hub. The main shaft is connected to the sun gear (also called the intermediate gear), the hub is connected to the planet carrier, and the internal gear ring (also called the outer gear) is fixed. The rear end of the main shaft is connected to the generator or the next stage transmission mechanism. A key feature is that there is no physical connection between the main shaft and the fixed load-bearing beam along the entire force transmission path; they maintain a spatial gap and are mechanically decoupled.

[0007] The hub is the core component connecting the aerodynamic interface (blades) and the mechanical structure interface. It has a large hole at its center that mates with the outer ring of the load-bearing bearing, allowing the entire hub to be "suspended" or "supported" at the front end of the fixed load-bearing beam via this bearing, forming a support relationship that allows it to rotate freely around the beam. Simultaneously, the hub is fixedly connected to the planetary carrier, inputting rotational motion into the speed-increasing device.

[0008] The core working principle of this structure lies in "path separation and dedicated components for specific purposes." When wind acts on the blades, the resulting force and motion are decomposed and transmitted along the following clear path: All non-torsional loads, such as aerodynamic thrust, aerodynamic bending moment, the weight of the blades and hub, rotational centrifugal force, and gyroscopic torque, are ultimately combined and act on the central bearing part of the hub.

[0009] These combined loads (primarily large radial forces, axial forces, and overturning moments) are transmitted through the hub to the outer ring of the load-bearing connection bearing.

[0010] The bearings smoothly transfer these loads to their inner ring and the outer front wall of the fixed load-bearing beam with which they are interference-fitted. Since the beam is fixed and does not rotate, the loads exist in the form of compression, bending, and shear within the beam's cross-section.

[0011] The load is transferred axially to the rear of the beam, passing through the platform connecting components at the rear end of the beam, and ultimately being entirely channeled into the robust lower platform and subsequent tower foundation structure. In this path, all components (except the rolling elements of the bearings) experience no rotational movement, fundamentally avoiding rotational bending fatigue.

[0012] This invention converts the wind energy captured by the wind turbine into pure torque that rotates the hub. This torque drives the planetary carrier, which is fixed to the hub, to rotate. After conversion (usually speed-up) by the internal planetary gear system, the torque is transmitted to the output end. The output end of the speed-up transmission device efficiently inputs the torque into the rotary transmission main shaft. The main shaft transmits the rotational power backward, driving the generator rotor to rotate and generate electricity. In this path, the main shaft ideally only bears torque and almost no lateral bending load from the wind turbine, thus exhibiting excellent torsional stress conditions.

[0013] The fixed load-bearing beam of this invention is only subjected to complex static / dynamic loads, while the rotary transmission main shaft is mainly subjected to torsion. The two perform their respective functions, greatly simplifying and optimizing the stress state.

[0014] This invention eliminates stress concentration sources such as the traditional spindle shoulder, allows for equal strength optimization of the beam cross section, resulting in more uniform stress distribution and significantly improved fatigue strength.

[0015] Specifically, this utility model discloses a wind turbine beam-shaft separated main load-bearing structure, including a lower platform, a fixed load-bearing beam, a rotary transmission main shaft, a hub, and a speed-increasing transmission device. The fixed load-bearing beam is a hollow structural component that is fixedly installed. Its front end is rotatably connected to the hub through a load-bearing connecting bearing, and its rear end is fixedly connected to the lower platform through a platform connecting component. The rotary transmission main shaft and the fixed load-bearing beam are mechanically separated and not directly connected. The power input end of the rotary transmission main shaft is connected to the wheel hub drive through the speed-increasing transmission device.

[0016] Furthermore, the geometric center axis of the fixed load-bearing beam is arranged coaxially with the ideal rotation axis of the wind turbine.

[0017] Furthermore, the load-bearing connecting bearing is a combined slewing bearing capable of simultaneously bearing radial load, axial load, and overturning moment.

[0018] Furthermore, the load-bearing connecting bearing is a double-row tapered roller bearing or a three-row cylindrical roller combination bearing.

[0019] Furthermore, the platform connecting component is a hinged mechanism that allows the fixed load-bearing beam to have a small angle adaptive adjustment capability at the rear connection.

[0020] Furthermore, the speed-increasing transmission device is a single-stage planetary gear mechanism, whose housing is fixedly connected to the hub, and whose output end is connected to the rotary transmission main shaft.

[0021] Furthermore, the cross-section of the fixed load-bearing beam is circular or rectangular, and its wall thickness or cross-sectional dimensions vary along the axial direction according to the principle of equal strength or the result of topology optimization.

[0022] Furthermore, the axis of the rotary transmission main shaft coincides with the axis of the fixed load-bearing beam.

[0023] The advantages of this invention compared to existing technologies are as follows: By completely independent mechanically setting the fixed load-bearing beam and the rotary transmission main shaft, and connecting them to the wheel hub through load-bearing bearings and reduction transmission devices respectively, this invention physically decouples the functions of load bearing and torque transmission. The fixed load-bearing beam is specifically designed to bear complex static and dynamic loads, while the rotary transmission main shaft focuses on transmitting torque. This simplifies and clarifies the force distribution on each core component, fundamentally avoiding complex stress states and providing a better foundation for structural design and life assessment.

[0024] Traditional spindles are prone to stress concentration at the hub and transmission connections due to abrupt geometric changes. In this invention, the fixed load-bearing beam transmits loads through large-area bearings, and its cross-section can be smoothly transitioned or optimized for equal strength, resulting in a more uniform stress distribution. Since the rotary transmission spindle does not bear bending loads, the stress level at its connections is also significantly reduced. This improves the overall fatigue resistance of the structure and extends the service life of the core load-bearing components.

[0025] The fixed load-bearing beam is installed statically and bears dynamic loads with relatively slow directional changes, rather than the high-frequency alternating bending stresses experienced by a traditional rotating spindle. This avoids the most unfavorable stress cycle type from a fatigue mechanism perspective, significantly delaying fatigue damage accumulation and improving the reliability and stability of the structure during long-term operation.

[0026] The load of this invention is transferred via a path from the wheel hub to the bearing, then to the fixed load-bearing beam, the platform connector, and finally the lower platform. This is a direct and efficient rigid force transmission path. The rear of the fixed load-bearing beam is connected to the platform via a hinge, providing stable support while releasing installation constraints. This ensures that the load is efficiently and stably transferred to the foundation, improving the overall structural rigidity and operational stability.

[0027] Due to the separation of functions, both the fixed load-bearing beam and the rotary transmission spindle can be designed with precision and optimization for their single dominant force mode, without the need to reserve too much redundancy to undertake additional functions. This creates conditions for the overall lightweighting of the core load-bearing and transmission system, which helps to reduce material consumption and manufacturing costs.

[0028] This utility model's structure naturally forms a static load-bearing module and a dynamic transmission module, facilitating separate pre-assembly, testing, and maintenance. During maintenance, a single module can be operated relatively independently without the need for complete disassembly, thereby reducing maintenance workload and downtime, and improving the maintainability and operational efficiency of the unit.

[0029] In summary, this utility model, through its innovative split-structure design, fundamentally improves the stress distribution mode of the traditional main load-bearing structure of wind turbines. It makes substantial progress in improving reliability, extending service life, optimizing weight control, and enhancing maintainability, and has significant practical value and application prospects. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 This is a schematic diagram of the structure of this utility model.

[0032] Figure 2 This is a side view of the structure of this utility model.

[0033] Figure 3 This is a top view of the structure of this utility model.

[0034] In the diagram: 1 is the lower platform, 2 is the fixed load-bearing beam, 3 is the rotary transmission main shaft, 4 is the load-bearing connecting bearing, 5 is the hub, 6 is the blade, 7 is the platform connecting component, and 8 is the speed-increasing transmission device. Detailed Implementation

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the specific embodiments described.

[0036] See Figure 1 , Figure 2 and Figure 3 In a preferred embodiment of this utility model: The lower platform 1 is the supporting base for the wind turbine nacelle.

[0037] The fixed load-bearing beam 2 is a hollow frustum-shaped structure forged or welded from high-strength alloy steel, with the larger end at the rear. It is bolted to the lower platform 1 via a flange-type platform connecting component 7. The smaller end of the fixed load-bearing beam 2 is at the front, and its outer cylindrical surface is ground to accommodate the load-bearing connecting bearing 4.

[0038] The load-bearing connecting bearing 4 is a double-row tapered roller bearing, with its inner ring mounted on the front end of the fixed load-bearing beam 2 and its outer ring mounted in the center hole of the hub 5.

[0039] The hub 5 is a cast steel component, and its outer edge is connected by three blades 6 with bolts. The right end face of the hub 5 is rigidly connected to the planetary carrier of the speed-increasing transmission device 8 (in this example, a first-stage planetary speed-increasing machine) by bolts, as shown in the figure.

[0040] The output end of the sun gear of the speed-increasing transmission device 8 is connected to the front end of the rotary transmission main shaft 3 via a high-strength spline. The rear end of the main shaft 3 is connected to a generator.

[0041] The rotary transmission main shaft 3 is located inside the fixed load-bearing beam 2, and its axis is parallel to and at a certain distance from the axis of the fixed load-bearing beam 2. One end of the rotary transmission main shaft 3 is connected to the hub 5 through the speed-increasing transmission device 8, and the other end of the rotary transmission main shaft 3 is connected to the generator through a two-stage or three-stage speed-increasing mechanism.

[0042] During unit operation, the wind turbine load is borne by the fixed load-bearing beam 2 through the load-bearing connecting bearing 4; the rotation of the wind turbine drives the planetary carrier of the planetary speed increaser 8 to rotate through the hub 5, and after being speed-increased by gears, it is output through the rotary transmission main shaft 3. The fixed load-bearing beam 2 and the rotary transmission main shaft 3 are completely independent in structure and mechanical transmission.

[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A wind turbine beam-shaft separated main load-bearing structure, comprising a lower platform (1), a fixed load-bearing beam (2), a rotary transmission main shaft (3), a hub (5), and a speed-increasing transmission device (8), characterized in that: The fixed load-bearing beam (2) is a hollow structural component that is fixedly installed. Its front end is rotatably connected to the hub (5) through a load-bearing connecting bearing (4), and its rear end is fixedly connected to the lower platform (1) through a platform connecting component (7). The rotary transmission main shaft (3) and the fixed load-bearing beam (2) are mechanically separated and not directly connected. The power input end of the rotary transmission main shaft (3) is connected to the wheel hub (5) through the speed-increasing transmission device (8).

2. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The geometric center axis of the fixed load-bearing beam (2) is arranged coaxially with the ideal rotation axis of the wind turbine.

3. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The load-bearing connecting bearing (4) is a combined slewing bearing capable of simultaneously bearing radial load, axial load and overturning moment.

4. The fan beam shaft disconnect primary load carrying structure of claim 3, wherein: The load-bearing connecting bearing (4) is a double-row tapered roller bearing or a three-row cylindrical roller combination bearing.

5. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The platform connecting component (7) is a hinge mechanism that allows the fixed load-bearing beam (2) to have a small angle adaptive adjustment capability at the rear end connection.

6. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The speed-increasing transmission device (8) is a first-stage planetary gear mechanism, whose housing is fixedly connected to the hub (5), and whose output end is connected to the rotary transmission main shaft (3).

7. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The cross-section of the fixed load-bearing beam (2) is circular or rectangular, and its wall thickness or cross-sectional dimensions vary along the axial direction according to the principle of equal strength or the result of topology optimization.

8. The fan beam shaft disconnect primary load carrying structure of claim 1, wherein: The axis of the rotary transmission main shaft (3) coincides with the axis of the fixed load-bearing beam (2).

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