A full-scale test machine and test method for a semi-direct-drive offshore wind turbine 1-1 transmission chain

Abstract

The application provides a full-size test machine and a test method for a 1:1 transmission chain of an offshore semi-direct-drive wind turbine 1, which comprises a concrete base, a bend seat fixed on the concrete base and simulating a wind turbine cabin, a generator mounting seat fixed at one end of the bend seat, and an angle between a central axis of the generator mounting seat and a horizontal plane being 8 degrees; a bearing mounting seat coaxially connected at one end of the generator mounting seat, a test bearing mounted on the bearing mounting seat, an inner ring of the test bearing being connected with a joint, and the joint being connected with a connecting sleeve assembly for simulating a main shaft of the wind turbine at a 1:1 ratio. The application adopts a transmission chain structure with a 1:1 ratio of an actual unit, completely reproduces an actual structure from a hub to a generator of the offshore semi-direct-drive wind turbine, truly restores an assembly relationship and a load transmission path of the transmission chain, completely eliminates data deviation caused by a reduced-scale model test, and is highly consistent with an actual operation condition in a test result, and reliability is significantly better than that of an existing reduced-scale test method.

Description

Technical Field

[0001] This invention belongs to the field of wind power equipment performance testing technology, specifically relating to a full-size testing machine and testing method for a 1:1 transmission chain of an offshore semi-direct drive wind turbine. Background Technology

[0002] The drive train (including main bearing, hub interface, medium speed gearbox and generator) of offshore semi-direct drive wind turbine is the core component of the unit. Its reliability directly affects the unit's service life and maintenance costs. As offshore wind power develops towards high power and long life, it is of great engineering significance to conduct full performance verification and life assessment of the drive train before the unit is put into actual operation.

[0003] However, existing testing devices for semi-direct drive transmission chains are mostly scaled-down models or discrete tests targeting only a single component. They cannot accurately reproduce the operating conditions of a 1:1 full-size main bearing and hub drive system under complex marine loads. This results in large deviations between test conditions and actual operating conditions, and insufficient reliability of verification results. Furthermore, existing devices apply loads in a single way, failing to simulate multi-dimensional loads such as axial force, radial force, and overturning moment. This makes it difficult to reproduce the real wind conditions where alternating and impact loads coexist at sea, and thus cannot provide reliable data support for transmission chain design optimization, fault prediction, and life assessment. Summary of the Invention

[0004] This invention provides a full-scale test machine and test method for a 1:1 transmission chain of a semi-direct drive offshore wind turbine, which solves the problems mentioned in the background art, such as existing test devices being mostly scaled-down models or single-component discrete tests, failing to truly reproduce the operating state of the 1:1 full-scale main bearing and hub transmission system under complex offshore loads, large deviations between test conditions and actual conditions, and lack of multi-dimensional load coupling simulation.

[0005] The technical solution adopted in this invention is: a full-size test machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine, including a concrete base, on which a 1:1 simulated wind turbine nacelle elbow seat is fixed, and a generator mounting seat is fixed at one end of the elbow seat, with the central axis of the generator mounting seat having an angle of 8° with the horizontal plane.

[0006] One end of the generator mounting base is coaxially connected to a bearing mounting base, on which a test bearing is mounted. The inner ring of the test bearing is connected to a joint, and the other end of the joint is connected to a connecting sleeve assembly for simulating the main shaft of a 1:1 wind turbine generator. The end of the connecting sleeve assembly is connected to an outer sleeve, and a test bearing is set at each of the front and rear ends inside the outer sleeve. The outer ring of the test bearing is fixed to the inner wall of the outer sleeve, and the inner ring is fitted on the outer periphery of the end of the connecting sleeve assembly. The outer sleeve is used to transfer the applied load to the connecting sleeve assembly.

[0007] The end of the outer sleeve is connected to a loading device, which is used to apply axial force, vertical force and horizontal force load to the connecting sleeve assembly;

[0008] It also includes drive components disposed on both radial sides of the connecting sleeve assembly and used to drive the connecting sleeve assembly to rotate.

[0009] The connecting sleeve assembly includes a first connecting sleeve, a second connecting sleeve, and a third connecting sleeve connected in series coaxially. One end of the first connecting sleeve is connected to the connector, and the end of the third connecting sleeve extends into the outer sleeve and mates with the inner ring of the test bearing.

[0010] The drive assembly includes a motor and a reducer fixed to the ground. A drive gear is mounted on the output shaft of the reducer. A gear ring is fixed to the outer periphery of the second connecting sleeve. The drive gear and the gear ring mesh with each other. The motor drives the connecting sleeve assembly to rotate around its central axis through the reducer.

[0011] The loading device includes an axial loading unit, which includes four axial cylinders arranged axially along the connecting sleeve assembly. The four axial cylinders are evenly distributed relative to the center of the outer sleeve. One end of each axial cylinder is fixed to the concrete base, and the other end is connected to the end face of the outer sleeve, for applying axial load to the connecting sleeve assembly.

[0012] The loading device also includes a vertical loading unit, which includes five vertical cylinders arranged in a vertical direction. The five vertical cylinders are divided into two groups, one group containing three vertical cylinders and the other group containing two vertical cylinders. The piston rod end of each vertical cylinder is connected to the outer wall of the outer sleeve and is used to apply vertical bending moment and radial force to the connecting sleeve assembly.

[0013] The loading device further includes a horizontal loading unit, which includes two horizontal cylinders arranged in a horizontal direction. The two horizontal cylinders are located on one side of the outer sleeve, and the piston rod end of each horizontal cylinder is connected to the outer wall of the outer sleeve to apply a horizontal bending moment and a radial force to the connecting sleeve assembly.

[0014] The concrete base is also provided with a bottom fixture and a connecting fixture. The bottom fixture is fixed to the upper surface of the concrete base and is used to support and fix the connecting fixture. The connecting fixture is located between the elbow seat and the bottom fixture, and its upper surface is inclined at an angle of 8°.

[0015] The bearing mounting base, elbow mounting base, and generator mounting base are all equipped with sensor mounting interfaces for installing vibration sensors, temperature sensors, strain sensors, and torque sensors to monitor the operating status of the test bearing and the auxiliary bearing in real time.

[0016] This application also provides a test method for a 1:1 full-scale test machine for the drive train of an offshore semi-direct drive wind turbine, which is applied to the above-mentioned test machine and includes the following steps:

[0017] Step 1: Assembly and pre-commissioning: Install the connecting sleeve assembly, test bearing, outer sleeve and auxiliary bearing coaxially on the elbow seat according to the actual fan assembly standard, calibrate the vibration, temperature, strain and torque sensors, and run the test under no-load to confirm that each component rotates smoothly, coaxiality and signal transmission are normal.

[0018] Step 2: Setting Operating Parameters: Based on the actual operating environment of the target offshore wind turbine, set the input speed and torque of the drive components to simulate different wind speed levels; set the axial force, vertical force and horizontal force load parameters through the axial loading unit, vertical loading unit and horizontal loading unit respectively to simulate the aerodynamic load of the offshore wind turbine; set the alternating load frequency, impact load intensity and number of test cycles.

[0019] Step 3: No-load performance calibration: Start the drive assembly and run it without load according to the set speed gradient. Collect the operating temperature, vibration amplitude, no-load torque of the connecting sleeve assembly and coaxiality deviation data of the test bearing and the auxiliary bearing, and establish a no-load reference data model.

[0020] Step 4: Multi-condition load test: While maintaining stable operation of the drive assembly, start the axial loading unit, vertical loading unit and horizontal loading unit in sequence, and apply static load, alternating load and impact load individually and in combination to simulate four typical marine conditions: low wind speed steady state, high wind speed turbulence, extreme gusts and sudden load. Collect the load distribution of the test bearing, stress and strain of the connecting sleeve assembly, torque transmission efficiency of the transmission chain and vibration and temperature data of the components in real time throughout the process.

[0021] Step 5: Fatigue life cycle test: Based on the load spectrum of the target wind turbine's entire life cycle, set the alternating load cycle parameters, perform long-term cyclic loading on the transmission chain, and periodically collect data on the wear of the test bearings and auxiliary bearings, lubrication status, fatigue deformation of the connecting sleeve assembly, and performance degradation of the transmission chain.

[0022] Step Six: Shutdown and Data Processing: After completing all working condition tests, gradually unload the loads of each loading unit and reduce the speed to stop the machine. Organize and analyze the collected data, evaluate the load adaptability, transmission efficiency and fatigue life of the test bearings, auxiliary bearings and connecting sleeve assemblies, and generate a test report.

[0023] Step 7: Post-test component inspection: Disassemble the connecting sleeve assembly, test bearing and auxiliary bearing, conduct visual inspection and dimensional accuracy re-measurement, analyze the wear and deformation patterns of each component under load, and verify the effectiveness of the test method.

[0024] In step four, real-time temperature threshold monitoring is implemented for each loading unit. When the temperature of the test bearing or the auxiliary bearing exceeds the warning value, the protection shutdown procedure is automatically triggered.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention adopts a transmission chain structure with a 1:1 scale to the actual unit, completely replicating the actual structure of the offshore semi-direct drive wind turbine from the hub to the generator, truly restoring the assembly relationship and load transmission path of the transmission chain, completely eliminating the data deviation caused by scaled-down model tests, and the test results are highly consistent with the actual operating conditions, with reliability significantly better than existing scaled-down test methods.

[0027] The loading device of the present invention includes an axial loading unit, a vertical loading unit, and a horizontal loading unit, which can realize the independent and coordinated application of axial force, radial force, and overturning moment. It supports multiple combined loading modes of static load, alternating load, and impact load, and can realistically reproduce various typical working conditions such as low wind speed steady state, high wind speed turbulence, and extreme gusts at sea, providing a complete load simulation capability for fatigue life testing and extreme working condition verification of transmission chains.

[0028] The generator mounting base of this invention has an angle of 8° between its central axis and the horizontal plane, which is consistent with the actual installation state of a semi-direct drive offshore wind turbine. This can accurately reproduce the asymmetric gravity component and load distribution characteristics of the transmission chain under inclined conditions, and avoid the test errors caused by installation deviations in existing horizontally arranged test devices.

[0029] The test method of this invention covers seven standardized steps: assembly and debugging, no-load calibration, multi-condition load coupling test, fatigue life cycle test, and post-test component inspection. The test process is complete, and the data acquisition covers multiple dimensions such as vibration, temperature, strain, and torque, which can provide complete and accurate data support for transmission chain design optimization, performance verification, and fault prediction. Attached Figure Description

[0030] Figure 1 This is a structural view of the present invention;

[0031] Figure 2 This is a partial enlarged view of the present invention.

[0032] in:

[0033] 1. Concrete base; 2. Bottom fixture; 3. Connecting fixture; 4. Elbow seat; 5. Generator mounting base; 6. Fixed plate; 7. Test bearing; 8. Locking plate; 9. Movable plate; 10. Joint; 11. First connecting sleeve; 12. Second connecting sleeve; 13. Third connecting sleeve; 14. Outer sleeve; 15. Axial cylinder; 16. Vertical cylinder; 17. Horizontal cylinder. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] As shown in the figure, a full-scale test machine for a 1:1 drivetrain of a semi-direct-drive offshore wind turbine includes a concrete base 1. A 1:1 scale model of a wind turbine nacelle, simulating an elbow seat 4, is fixed to the concrete base 1. A generator mounting base 5 is fixed to one end of the elbow seat 4. The central axis of the generator mounting base 5 forms an angle of 8° with the horizontal plane. Specifically, to achieve the installation and fixation of the elbow seat 4, a bottom fixture 2 and a connecting fixture 3 are also provided on the concrete base 1. The bottom fixture 2 is fixed to the upper surface of the concrete base 1 for supporting and fixing. The connecting fixture 3 is positioned between the elbow seat 4 and the bottom fixture 2. Its upper surface is inclined at an angle of 8°. The elbow seat 4 is a right-angle elbow structure with its two ends having perpendicular central axes. One end is fixedly connected to the connecting fixture 3 by bolts, while the other end extends along the axis of the generator mounting base 5, so that the central axis of the generator mounting base 5 forms an 8° angle with the horizontal plane, thereby replicating the actual spatial installation posture of the offshore semi-direct drive wind turbine nacelle in a 1:1 ratio.

[0036] One end of the generator mounting base 5 is coaxially connected to a bearing mounting base, on which a test bearing 7 is mounted. In this example, the bearing mounting base includes a fixed plate 6, a locking plate 8, and a movable plate 9. The locking plate 8 and the movable plate 9 are coaxial and interlocked. The test bearing 7 is located between the fixed plate 6 and the locking plate 8. The test bearing 7 is a double-row tapered slewing bearing. Its outer ring is fixedly connected to the locking plate 8, the fixed plate 6, and the generator mounting base 5 by bolts, so that the outer ring of the test bearing 7 always remains fixed. The inner ring of the test bearing 7 is connected to the movable plate 9 and the connector 10 by bolts. After the connector 10 rotates, it can drive the inner ring of the test bearing 7 to rotate relative to the outer ring, thereby simulating the working state of the bearing.

[0037] The inner ring of the test bearing 7 is connected to a joint 10. The other end of the joint 10 is connected to a connecting sleeve assembly for simulating the main shaft of a 1:1 wind turbine generator. The end of the connecting sleeve assembly is connected to an outer sleeve 14. A test bearing is provided at each of the front and rear ends of the outer sleeve 14. The outer ring of the test bearing is fixed to the inner wall of the outer sleeve 14, and the inner ring is fitted on the outer periphery of the end of the connecting sleeve assembly. The outer sleeve 14 is used to transfer the applied load to the connecting sleeve assembly. The end of the outer sleeve 14 is connected to a loading device, which is used to apply axial force, vertical force and horizontal force load to the connecting sleeve assembly. It also includes a drive assembly provided on both radial sides of the connecting sleeve assembly for driving the connecting sleeve assembly to rotate.

[0038] The connecting sleeve assembly includes a first connecting sleeve 11, a second connecting sleeve 12, and a third connecting sleeve 13 connected in series coaxially. One end of the first connecting sleeve 11 is connected to the connector 10, and the end of the third connecting sleeve 13 extends into the outer sleeve 14 and mates with the inner ring of the test bearing. The three connecting sleeves are connected in series to form a transmission shaft system for simulating the main shaft of a 1:1 wind turbine generator. The segmented series structure design facilitates the individual processing, manufacturing, and assembly of each connecting sleeve, reducing the manufacturing difficulty of the full-size main shaft. Furthermore, individual connecting sleeves can be replaced or adjusted as needed under different testing requirements, providing good maintenance convenience and universal adaptability.

[0039] The drive assembly includes a motor and a reducer fixed to the ground. A drive gear is mounted on the output shaft of the reducer, and a gear ring is fixed to the outer circumference of the second connecting sleeve 12. The drive gear meshes with the gear ring, and the motor drives the connecting sleeve assembly to rotate around its central axis through the reducer. The drive assembly is fixed to the ground, ensuring structural stability and minimizing vibration interference. By adjusting the motor's output speed through the reducer, the rotational speed and input torque of the connecting sleeve assembly can be precisely controlled, thus simulating the power input of the wind turbine to the transmission chain under different wind speed levels. The gear and gear ring meshing transmission method offers high transmission efficiency and strong load-bearing capacity, meeting the requirements for high-torque rotational drive of a full-size transmission chain. Furthermore, positioning the drive gear at the second connecting sleeve 12 ensures that the point of application of the driving force is located in the central region of the connecting sleeve assembly, reducing the additional load impact of the driving force on the bearings at both ends of the connecting sleeve assembly and ensuring the accuracy of the test data.

[0040] The loading device includes an axial loading unit, which comprises four axial cylinders 15 arranged axially along the connecting sleeve assembly. The four axial cylinders 15 are evenly distributed relative to the center of the outer sleeve 14. One end of each axial cylinder 15 is fixed to the concrete base 1, and the other end is connected to the end face of the outer sleeve 14, for applying axial load to the connecting sleeve assembly. The four axial cylinders 15 are evenly distributed circumferentially to ensure that the axial load is evenly transmitted to the connecting sleeve assembly along the end face of the outer sleeve 14, avoiding additional bending moment caused by load offset, and ensuring the accuracy and stability of axial loading. The fixed end of the axial cylinder 15 is anchored to the concrete base 1, providing sufficient reaction force support to meet the large axial load application requirements of the full-scale transmission chain test, and realistically simulating the axial loading condition of the transmission chain main bearing by the thrust of an offshore wind turbine.

[0041] The loading device also includes a vertical loading unit, which comprises five vertical cylinders 16 arranged vertically. These five cylinders are divided into two groups: one group containing three cylinders closer to the axial loading unit, and the other group containing two cylinders. The piston rod end of each cylinder 16 is connected to the outer wall of the outer sleeve 14, and is used to apply vertical bending moment and radial force to the connecting sleeve assembly. By dividing the five cylinders 16 into two groups and arranging them at intervals along the axial direction of the connecting sleeve assembly, different magnitudes of vertical bending moment can be generated on the connecting sleeve assembly by adjusting the load magnitude and direction of the two groups of cylinders 16, realistically simulating the overturning bending moment condition generated by the aerodynamic load of an offshore wind turbine on the main shaft. Simultaneously, the differentiated loading of the two groups of cylinders also enables precise control of the radial force distribution at different positions along the axial direction of the connecting sleeve assembly, significantly improving the simulation accuracy and flexibility of the vertical working condition.

[0042] The loading device also includes a horizontal loading unit, which comprises two horizontal cylinders 17 arranged horizontally. The two horizontal cylinders 17 are located on one side of the outer sleeve 14, and the piston rod end of each horizontal cylinder 17 is connected to the outer wall of the outer sleeve 14. These cylinders are used to apply horizontal bending moments and radial forces to the connecting sleeve assembly. The horizontal loading unit cooperates with the vertical loading unit to achieve independent application and coupled loading of vertical and horizontal loads, thereby generating a combined bending moment and radial force in any direction on the connecting sleeve assembly. This fully replicates the multi-dimensional and complex load state experienced by the drive train main shaft under marine wind conditions, providing realistic and reliable load input conditions for drive train fatigue life assessment and extreme condition verification.

[0043] The bearing mounting base, elbow base 4, and generator mounting base 5 are all equipped with sensor mounting interfaces for installing vibration sensors, temperature sensors, strain sensors, and torque sensors to monitor the operating status of the test bearing 7 and the auxiliary bearing in real time. By reserving sensor mounting interfaces in the above-mentioned key locations, comprehensive and real-time data acquisition of vibration amplitude, operating temperature, stress and strain, and torque transmission efficiency of each key component of the transmission chain can be achieved, realizing continuous monitoring of the operating status of the test bearing 7 and the auxiliary bearing. When the component temperature or vibration amplitude exceeds the warning threshold, the protection shutdown procedure can be triggered in time to ensure the safety of the test process. At the same time, the comprehensive analysis of multi-dimensional sensor data can provide complete and reliable data support for fault prediction, performance evaluation, and design optimization of the transmission chain.

[0044] In addition, to facilitate the debugging and support of the entire testing machine, an adjustable support seat is set on the radial side of the connecting sleeve assembly. This is used to center and calibrate the connecting sleeve assembly during the installation and debugging phase, eliminate the cumulative coaxiality error of the three-section series structure and the gravity sagging effect caused by the 8° tilt installation, and ensure the precise centering of the transmission chain axis under test conditions.

[0045] This application also provides a test method for a 1:1 full-scale test machine for the drive train of an offshore semi-direct drive wind turbine, which is applied to the above-mentioned test machine and includes the following steps:

[0046] Step 1: Assembly and pre-commissioning: Install the connecting sleeve assembly, test bearing 7, outer sleeve 14 and auxiliary bearing coaxially on the elbow seat 4 according to the actual fan assembly standard, calibrate the vibration, temperature, strain and torque sensors, and run the test under no-load to confirm that each component rotates smoothly, has coaxiality and normal signal transmission.

[0047] Step 2: Setting Operating Parameters: Based on the actual operating environment of the target offshore wind turbine, set the input speed and torque of the drive components to simulate different wind speed levels; set the axial force, vertical force and horizontal force load parameters through the axial loading unit, vertical loading unit and horizontal loading unit respectively to simulate the aerodynamic load of the offshore wind turbine; set the alternating load frequency, impact load intensity and number of test cycles.

[0048] Step 3: No-load performance calibration: Start the drive assembly and run it without load according to the set speed gradient. Collect the operating temperature, vibration amplitude, no-load torque of the connecting sleeve assembly and coaxiality deviation data of the test bearing 7 and the auxiliary bearing, and establish a no-load reference data model.

[0049] Step 4: Multi-condition load test: While maintaining stable operation of the drive assembly, start the axial loading unit, vertical loading unit and horizontal loading unit in sequence, and apply static load, alternating load and impact load individually and in combination to simulate four typical marine conditions: low wind speed steady state, high wind speed turbulence, extreme gusts and sudden load. Collect load distribution of test bearing 7, stress and strain of connecting sleeve assembly, torque transmission efficiency of transmission chain and vibration temperature of components in real time throughout the process.

[0050] Step 5: Fatigue life cycle test: Based on the load spectrum of the target wind turbine's entire life cycle, set the alternating load cycle parameters, perform long-term cyclic loading on the transmission chain, and periodically collect data on the wear amount, lubrication status, fatigue deformation of the connecting sleeve assembly, and performance degradation of the transmission chain of the test bearing 7 and the auxiliary bearing;

[0051] Step Six: Shutdown and Data Processing: After completing all working condition tests, gradually unload the loads of each loading unit and reduce the speed to stop the machine. Organize and analyze the collected data, evaluate the load adaptability, transmission efficiency and fatigue life of the test bearing 7, the auxiliary bearing and the connecting sleeve assembly, and generate a test report.

[0052] Step 7: Post-test component inspection: Disassemble the connecting sleeve assembly, test bearing 7 and accompanying bearing, conduct visual inspection and dimensional accuracy re-measurement, analyze the wear and deformation patterns of each component under load, and verify the effectiveness of the test method.

[0053] In step four, real-time temperature threshold monitoring is implemented for each loading unit. When the temperature of the test bearing 7 or the auxiliary bearing exceeds the warning value, the protection shutdown procedure is automatically triggered.

[0054] Specifically, the following test object is a wind turbine generator main shaft bearing with an outer diameter of 3587mm, an inner diameter of 2680mm, and a height of 612mm. The testing machine and testing method of this invention are used, and the specific steps are as follows:

[0055] 1. Assembly and Commissioning: The main shaft bearing and test bearings are coaxially installed on the designated fixture according to the actual fan assembly standards. The meshing of gears and gear rings between the drive assembly and the connecting sleeve assembly is completed, as well as the connection of each loading unit to the outer sleeve end face and outer wall. Pressure sensors, torque and speed sensors, laser displacement sensors, temperature sensors, and acceleration sensors are calibrated to ensure that all sensors are within their qualified calibration period, and that the input load error and average output speed error do not exceed ±5%. Before formal commissioning, a compensating loading force is set according to the self-weight of the shaft connection fixture to ensure that the bearings are in a stress-free state. Static lubrication cleaning is performed for 36 hours, followed by dynamic lubrication cleaning for 24 hours to remove contaminants from the pipelines and bearings, providing a clean lubrication environment for subsequent tests.

[0056] 2. Operating Parameter Settings: Based on the actual operating environment of the wind turbine, the input speed range of the drive component is set to 2–12 rpm, covering low wind speed to rated wind speed conditions; the maximum axial force is set to 2064.8 kN, the maximum radial force is set to 3299.38 kN, and the maximum overturning moment is set to 31173.966 kN·m, simulating the multi-dimensional loading of the main shaft bearing by the aerodynamic load of the offshore wind turbine; at the same time, the alternating load frequency, impact load intensity, and number of test cycles for each stage are set, and the automatic computer recording frequency is determined to be 1 time / min, while the manual recording frequency is set according to the requirements of each test stage.

[0057] 3. No-load performance calibration: After flushing, start the drive assembly and run it under no-load at speeds of 2 rpm, 6 rpm, and 12 rpm. Real-time data collection is performed on the operating temperature, vibration amplitude, no-load torque of the connecting sleeve assembly, and coaxiality deviation of the test bearing and the auxiliary bearing. A no-load baseline data model is established as a reference for comparing test data in subsequent stages. During no-load operation, observe the hydraulic lines for leaks and the test bench for abnormal noises. Only after confirming smooth operation of all components can the formal loading test stage begin.

[0058] 4. Conduct running-in and accelerated fatigue loading tests, gradually increasing the load from low load and low speed conditions, and finally running continuously for approximately 2895 hours at rated load and speed of 12 rpm to complete the entire accelerated fatigue test process. Throughout the test, core data such as bearing inner and outer ring temperatures, vibration amplitude, rotational torque, lubricating oil temperature and cleanliness, and bearing displacement in all directions were collected in real time. The machine was stopped at 50h, 100h, and 150h of operation, and the internal condition of the bearing was observed and photographed using an endoscope through the viewing hole. After 150h, observations and records were made every 250h of operation to monitor changes in the operating status of the bearing raceway, rolling elements, and cage.

[0059] 5. Start-up and Idle Operation Tests: After the fatigue loading test, start-up, emergency stop, and idle operation tests were conducted sequentially. The start-up and emergency stop tests consisted of 1500 cycles, each simulating the entire process of the fan starting from a standstill, stabilizing at rated speed, and then decelerating to a stop, including an emergency stop. The idle operation test consisted of 4000 cycles, simulating alternating forward and reverse start-up and stop conditions of the bearing at low speeds. During both tests, the bearing temperature and vibration were monitored in real time. At specified operating time points, the machine was stopped, and the internal condition of the bearing was observed using an endoscope and photographed.

[0060] 6. Ultimate Load Test: At a speed of 12 rpm, 16 ultimate load conditions were applied sequentially, each lasting 300 seconds, completing one full cycle to comprehensively verify the bearing's load-bearing capacity and structural reliability under extreme wind conditions. Throughout the test, manual recording was performed every 5 minutes. Before and after the test, an endoscope was used to observe the internal condition of the bearing and photographs were taken to ensure that the bearing showed no cracks, abnormal deformation, or other failure phenomena under ultimate load conditions.

[0061] 7. Shutdown and Data Processing: After completing all working condition tests, gradually unload the loads of each loading unit and reduce the speed to zero before stopping the machine; systematically organize and analyze the bearing temperature, vibration, torque, displacement, and oil condition data collected throughout the test, evaluate the load adaptability, transmission efficiency, and fatigue life of the spindle bearing, and issue interim test reports at the 5th, 15th, and 25th years of the accelerated fatigue test, respectively, and issue special reports after the start-stop + emergency stop and idling tests.

[0062] 8. Post-test component inspection: After shutdown, disassemble the components and clean them thoroughly. Perform a visual inspection on the contact condition of the inner and outer ring raceways, the integrity of the rolling element surfaces, and the wear and deformation of the cage. Analyze the wear and deformation patterns of each component under load. Re-measure the bearing starting torque, axial clearance, end face runout, raceway angle, and hardened layer depth, and perform magnetic particle testing on the inner and outer ring raceways. The inspection results must meet the Class I qualification standard to verify the effectiveness of the test method and the accuracy of the test results of this invention.

[0063] Experimental results show that this method can accurately obtain the full-condition performance data of the main shaft bearing, truly reflect the operating status of the bearing under complex loads at sea, and the reliability of the test data is significantly better than that of the traditional scaled-down test method. It can provide reliable data support for the design optimization and life assessment of the main shaft bearing of offshore semi-direct drive wind turbine.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A full-scale testing machine for a 1:1 drive train of an offshore semi-direct drive wind turbine, characterized in that, Includes a concrete base (1), on which a 1:1 simulated wind turbine nacelle elbow seat (4) is fixed, and a generator mounting seat (5) is fixed at one end of the elbow seat (4), with the central axis of the generator mounting seat (5) at an angle of 8° to the horizontal plane. One end of the generator mounting base (5) is coaxially connected to a bearing mounting base, and a test bearing (7) is installed on the bearing mounting base. The inner ring of the test bearing (7) is connected to a joint (10). The other end of the joint (10) is connected to a connecting sleeve assembly for 1:1 simulation of the main shaft of the wind turbine generator. The end of the connecting sleeve assembly is connected to an outer sleeve (14). A test bearing is provided at each of the front and rear ends of the outer sleeve (14). The outer ring of the test bearing is fixed to the inner wall of the outer sleeve (14). The inner ring is fitted on the outer periphery of the end of the connecting sleeve assembly. The outer sleeve (14) is used to transfer the load to the connecting sleeve assembly. The end of the outer sleeve (14) is connected to a loading device, which is used to apply axial force, vertical force and horizontal force load to the connecting sleeve assembly; It also includes drive components disposed on both radial sides of the connecting sleeve assembly and used to drive the connecting sleeve assembly to rotate.

2. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: The connecting sleeve assembly includes a first connecting sleeve (11), a second connecting sleeve (12), and a third connecting sleeve (13) connected in series on the same axis. One end of the first connecting sleeve (11) is connected to the connector (10), and the end of the third connecting sleeve (13) extends into the outer sleeve (14) and mates with the inner ring of the test bearing.

3. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 2, characterized in that: The drive assembly includes a motor and a reducer fixed to the ground. A drive gear is mounted on the output shaft of the reducer. A gear ring is fixed on the outer periphery of the second connecting sleeve (12). The drive gear meshes with the gear ring. The motor drives the connecting sleeve assembly to rotate around its central axis through the reducer.

4. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: The loading device includes an axial loading unit, which includes four axial cylinders (15) arranged axially along the connecting sleeve assembly. The four axial cylinders (15) are evenly distributed relative to the center of the outer sleeve (14). One end of each axial cylinder (15) is fixed to the concrete base (1), and the other end is connected to the end face of the outer sleeve (14) for applying axial load to the connecting sleeve assembly.

5. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: The loading device also includes a vertical loading unit, which includes five vertical cylinders (16) arranged in the vertical direction. The five vertical cylinders (16) are divided into two groups, one group containing three vertical cylinders (16) and the other group containing two vertical cylinders (16) closer to the axial loading unit. The piston rod end of each vertical cylinder (16) is connected to the outer wall of the outer sleeve (14) for applying vertical bending moment and radial force to the connecting sleeve assembly.

6. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: The loading device also includes a horizontal loading unit, which includes two horizontal cylinders (17) arranged in the horizontal direction. The two horizontal cylinders (17) are located on one side of the outer sleeve (14). The piston rod end of each horizontal cylinder (17) is connected to the outer wall of the outer sleeve (14) to apply horizontal bending moment and radial force to the connecting sleeve assembly.

7. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: The concrete base (1) is also provided with a bottom fixture (2) and a connecting fixture (3). The bottom fixture (2) is fixed to the upper surface of the concrete base (1) and is used to support and fix the connecting fixture (3). The connecting fixture (3) is located between the elbow seat (4) and the bottom fixture (2), and its upper surface is inclined at an angle of 8°.

8. The full-scale testing machine for a 1:1 transmission chain of a semi-direct drive offshore wind turbine as described in claim 1, characterized in that: Sensor mounting interfaces are reserved on the bearing mounting base, elbow base (4) and generator mounting base (5) for installing vibration sensors, temperature sensors, strain sensors and torque sensors to monitor the operating status of the test bearing (7) and the accompanying bearing in real time.

9. A test method for a full-scale test machine for a 1:1 drive train of an offshore semi-direct drive wind turbine, wherein the test machine described in any one of claims 1-8 is used, characterized in that, Includes the following steps: Step 1: Assembly and pre-commissioning: Install the connecting sleeve assembly, test bearing (7), outer sleeve (14) and auxiliary bearing coaxially on the elbow seat (4) according to the actual fan assembly standard, calibrate the vibration, temperature, strain and torque sensors, run under no-load test, and confirm that each component rotates smoothly, coaxiality and signal transmission are normal. Step 2: Setting Operating Parameters: Based on the actual operating environment of the target offshore wind turbine, set the input speed and torque of the drive components to simulate different wind speed levels; set the axial force, vertical force and horizontal force load parameters through the axial loading unit, vertical loading unit and horizontal loading unit respectively to simulate the aerodynamic load of the offshore wind turbine; set the alternating load frequency, impact load intensity and number of test cycles. Step 3: No-load performance calibration: Start the drive assembly and run it without load according to the set speed gradient. Collect the operating temperature, vibration amplitude, no-load torque of the connecting sleeve assembly and coaxiality deviation data of the test bearing (7) and the accompanying bearing, and establish a no-load reference data model. Step 4: Multi-condition load test: Keep the drive components running stably, start the axial loading unit, vertical loading unit and horizontal loading unit in sequence, apply static load, alternating load and impact load individually and in combination step by step, simulate four typical marine conditions: low wind speed steady state, high wind speed turbulence, extreme gusts and sudden load, and collect the load distribution of the test bearing (7), stress and strain of the connecting sleeve components, torque transmission efficiency of the transmission chain and vibration temperature data of the components in real time throughout the process; Step 5: Fatigue life cycle test: Based on the load spectrum of the target wind turbine's entire life cycle, set the alternating load cycle parameters, perform long-term cyclic loading on the transmission chain, and periodically collect data on the wear amount, lubrication status, fatigue deformation of the connecting sleeve assembly and performance decay of the transmission chain of the test bearing (7) and the accompanying bearing; Step 6: Shutdown and data processing: After completing all working condition tests, gradually unload the load of each loading unit and stop the machine at a reduced speed. Organize and analyze the collected data, evaluate the load adaptability, transmission efficiency and fatigue life of the test bearing (7), the accompanying bearing and the connecting sleeve assembly, and generate a test report. Step 7: Post-test component inspection: Disassemble the connecting sleeve assembly, test bearing (7) and accompanying bearing, conduct appearance inspection and dimensional accuracy re-measurement, analyze the wear and deformation law of each component under load, and verify the effectiveness of the test method.

10. The test method for a full-scale test machine for a 1:1 transmission chain of an offshore semi-direct drive wind turbine as described in claim 9, characterized in that: In step four, real-time temperature threshold monitoring is implemented for each loading unit. When the temperature of the test bearing (7) or the accompanying bearing exceeds the warning value, the protection shutdown procedure is automatically triggered.

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