Hydraulic control unloading system of wind generating set

Abstract

The utility model relates to the technical field of wind driven generators, in particular to a hydraulic control unloading system of a wind driven generator set. One end of the oil cylinder abuts against a fixed base, and the other end of the oil cylinder abuts against an upper end connecting plate through a reset spring; the two sides, away from the end face of the connecting and fixing base, of the oil cylinder fixedly communicate with the hydraulic pipe, and a guide rod is arranged at the end, away from the oil cylinder, of the hydraulic pipe. Two side walls of the oil cylinder are connected with oil pipes which are provided with electromagnetic flow valves; a push rod cavity is formed between the two hydraulic pipes, a push rod is installed at one end of the push rod cavity, and a pre-tightening spring is arranged between the push rod and the push rod cavity. The end, away from the push rod cavity, of the push rod penetrates through the upper end connecting plate, and movement between the push rod and the upper end connecting plate is limited through a check block. Accurate control and feedback adjustment of the pre-tightening force of the floating end bearing are achieved, meanwhile, the device is easy to install and maintain, and the overall operation stability of the wind generating set can be remarkably improved.

Description

Technical Field

[0001] The utility model relates to the technical field of wind generators, in particular to a hydraulic control unloading system for a wind generator set. Background Art

[0002] With the increasing global emphasis on clean energy, wind power generation has become a vital component of the renewable energy sector. As the core equipment for wind energy conversion, the performance of wind turbines directly impacts the power generation efficiency, equipment lifespan, and maintenance costs of the entire wind farm. However, bearings, as precision core components in the wind turbine main shaft transmission system, are susceptible to severe spalling of the inner and outer raceways under long-term, complex, alternating loads, leading to main shaft system failure [1-2].

[0003] [1] Zhang Liang, Zhang Hao, Cai Guowei. The multiclass fault diagnosis of wind turbine bearing based on multisource signal fusion and deep learning generative model [J]. IEEE Transactions on Instrumentation and Measurement, 2022, 71(6): 3514212.

[0004] [2] Liang Yong. Fatigue life prediction of wind turbine main shaft bearings[D]. Lanzhou: Lanzhou University of Technology, 2013.

[0005] Generally speaking, the service life of the fixed-end bearing in the main shaft drive system is much shorter than the design life of the entire machine. However, the main shaft systems of mainstream doubly-fed wind turbines use spherical roller bearings (SRBs) at both the floating and thrust ends. The failure rate of these bearings is significantly higher than expected. Within a 6-10 year service life, the failure rate of the thrust bearing in wind turbines with this layout can be as high as 20-30%. Therefore, in order to effectively extend the service life of the thrust bearing, it is crucial to reasonably reduce its axial force.

[0006] Current research focuses on passive unloading devices, which are simpler in design and rely primarily on external forces or natural phenomena (such as gravity or springs) to adjust the bearing load. For example, some wind turbines use a dedicated adjustment device to distribute the axial load borne by the thrust bearing to the floating bearing.

[0007] While existing technologies have explored solutions to the problem of excessive axial force on thrust bearings, the passive unloading device, once installed, acts as a permanent force on the floating bearing, causing it to constantly bear the force. This significantly reduces the floating bearing's service life. Therefore, simplifying the design and improving efficiency while ensuring technical reliability remain pressing challenges in current technology. Utility Model Content

[0008] In response to the deficiencies in the prior art, the present invention provides a wind turbine generator set monitoring and constant-pressure axial unloading system. By introducing a combined active and passive unloading method into the main bearing system of the wind turbine generator set, the axial pressure on the thrust bearing is effectively reduced, thereby increasing its service life and the operational stability of the wind turbine generator set. In view of the fact that the existing wind turbine generator set main bearing unloading method requires a long period of time to apply a preload force to the floating end bearing, which significantly increases the working pressure of the floating end bearing and reduces the service life of the floating end bearing, the device structure of the present invention is more practical. By using a reset spring, a preload spring, a hydraulic telescopic device, a pressure sensor, an electromagnetic flow valve and a controller, etc., precise control of the floating end bearing preload force and force feedback adjustment can be achieved. At the same time, the device is also easy to install and maintain, and can significantly improve the overall operational stability of the wind turbine generator set.

[0009] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is a hydraulic control unloading system for a wind turbine generator set, comprising an oil cylinder, one end of which is tightly connected to a fixed base, and the other end of which is abutted against an upper connecting plate via a return spring;

[0010] The two sides of the oil cylinder away from the end surface of the fixed base are fixedly connected to the hydraulic pipe, and the end of the hydraulic pipe away from the oil cylinder is provided with a guide rod, and a return spring is installed on the guide rod;

[0011] The two side walls of the oil cylinder are connected to oil pipes, and electromagnetic flow valves are installed on the oil pipes;

[0012] A push rod cavity is provided between the two hydraulic pipes, a push rod is installed at one end of the push rod cavity, and a preload spring is provided between the push rod and the push rod cavity;

[0013] One end of the push rod away from the push rod cavity passes through the upper end connecting plate, and the movement between the push rod and the upper end connecting plate is limited by a stop block.

[0014] Furthermore, a pressure sensor is provided on the end surface of the guide rod away from the hydraulic pipe.

[0015] Furthermore, the push rod is clearance-fitted with the upper end connecting plate.

[0016] Furthermore, the guide rod is fixedly connected to the piston in the hydraulic pipe.

[0017] Furthermore, a controller is provided on the side wall of the oil cylinder.

[0018] Furthermore, the return spring is connected to the upper end connecting plate and the guide rod via a slot.

[0019] Furthermore, the preload spring is connected to the push rod and the push rod cavity via a slot.

[0020] Furthermore, the electromagnetic flow valve is installed near one end of the oil cylinder.

[0021] Furthermore, the electromagnetic flow valve is fixed on the oil cylinder.

[0022] Furthermore, under the action of the preload spring, one end of the push rod cavity rests against the oil cylinder.

[0023] Advantages of this utility model:

[0024] 1) Automatic preload adjustment

[0025] By utilizing the compression effect of the spring to apply a preliminary preload force to the floating end bearing, the utility model realizes automatic adjustment of the bearing unloading force, avoids the trouble of manual adjustment of the preload force in the traditional method, and improves the automation level and operation efficiency of the device.

[0026] 2) Accurate unloading force response control

[0027] A pressure sensor monitors the unloading system's unloading force in real time. The pressure signal from the pressure sensor on the guide rod is transmitted to the main controller, enabling the hydraulic expansion mechanism to accurately respond and apply unloading force to the floating bearing. This precise control also adjusts the force applied by the top plate to the floating bearing. This precise control helps maintain smooth system operation and prevents bearing damage caused by excessive or insufficient pressure.

[0028] 3) Effective implementation of unloading function

[0029] By controlling the expansion and contraction of the hydraulic expansion mechanism, an appropriate reaction force is automatically applied to the floating bearing when the axial force reaches the set value, effectively achieving unloading. This technology not only effectively reduces the load on the floating bearing, but also extends the service life of the equipment and reduces maintenance costs.

[0030] 4) Efficiency of feedback control system

[0031] When the pressure sensor on the guide rod surface detects the corresponding pressure value, the electromagnetic flow valve is closed through the feedback signal controller, automatically maintaining the fixed working state of the hydraulic expansion and contraction device. This precise feedback control mechanism ensures the stability and reliability of the equipment and reduces the error of human operation. At the same time, if the axial force on the floating end bearing does not reach the preset value of the pressure sensor, the hydraulic expansion and contraction device will be closed. The reaction force of the reset spring plus the axial force exerted by the wind wheel on the floating end bearing will automatically reset the hydraulic expansion and contraction device.

[0032] 5) Simplified structural design

[0033] This new design utilizes a hydraulic expansion and contraction mechanism linked to a pressure sensor, eliminating the need for complex mechanical adjustment devices or manual adjustment components, significantly simplifying the system structure. This simplified design not only reduces production and maintenance costs, but also improves the overall reliability and ease of use of the system.

[0034] 6) Improve the adaptability and flexibility of the system

[0035] This device can automatically adjust the applied force according to different working conditions, has a wide range of adaptability, can effectively respond to different load changes and working conditions, and enhances the adaptability and flexibility of the system.

[0036] 7) Reduce failure rate and maintenance costs

[0037] Through precise pressure control and automatic unloading function, the system can avoid mechanical failures caused by overload or unbalanced load, thereby reducing the failure rate and maintenance frequency of the equipment and saving maintenance costs in long-term operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a structural diagram of the hydraulic control unloading system of the wind turbine generator set provided by the utility model;

[0039] Figure 2 A bottom view of the hydraulic control unloading system of a wind turbine generator set provided by the utility model;

[0040] Figure 3 A schematic diagram of the structure of the hydraulic pipe provided by the utility model;

[0041] Figure 4 A side view of the hydraulic pipe provided by the utility model;

[0042] Figure 5 A schematic diagram of the structure of the oil cylinder provided by the utility model;

[0043] Figure 6 A cross-sectional view of the push rod cavity and the push rod provided by the utility model;

[0044] Among them: upper end connecting plate 1, return spring 2, push rod 3, guide rod 4, block 5, oil pipe 6, electromagnetic flow valve 7, connecting fixed seat 8, oil cylinder 9, hydraulic pipe 10, push rod cavity 11, controller 12, pressure sensor 13, preload spring 14. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0046] The technical solution of the present invention is primarily used for axial unloading of the main shaft system in a wind turbine generator set, particularly to address the adverse effects of the axial force generated by the rotating rotor on the service life of the thrust bearing during wind turbine operation. However, the present invention applies a certain unloading force to the floating bearing, allowing the floating bearing to bear a portion of the axial load, thereby achieving effective axial unloading and reducing the excessive axial force borne by the thrust bearing during operation. Furthermore, the axial force borne by the floating bearing can be monitored in real time. A pressure sensor feeds back a signal to a controller, which in turn controls the electromagnetic flow valve to cause the hydraulic preload device to extend and retract forward, applying a certain unloading force to the floating bearing, thereby preventing premature failure of the floating bearing due to excessive axial load. Furthermore, the present invention effectively extends the service life of the thrust bearing and prevents premature wear and failure of the thrust bearing due to excessive axial force. The application of this technical solution can significantly improve the operational stability of the wind turbine, reduce maintenance costs, extend the service life of the thrust bearing, and enhance the economic benefits and reliability of the wind turbine generator set.

[0047] like Figures 1-6 As shown, this embodiment provides a hydraulic control unloading system for a wind turbine generator set, comprising a cylinder 9, one end of the cylinder 9 (attached Figure 1 The middle right end) is tightly connected to the fixed base 8, and the other end is in contact with the upper connecting plate 1 through the return spring 2; the bottom of the fixed base 8 is connected to the stop ring installed on the bearing seat by bolts to achieve the function of connecting the fixed base 8, and the top of the fixed base 8 (i.e. the attached Figure 1 The left end) is pressed against the bottom of the oil cylinder 9, and its main function is to fix the constant pressure axial unloading system;

[0048] The two sides of the oil cylinder 9 away from the end surface connected to the fixed base 8 are fixedly connected to the hydraulic pipe 10. A guide rod 4 is provided at the end of the hydraulic pipe 10 away from the oil cylinder 9, and a return spring 2 is installed on the guide rod 4; a push rod cavity 11 is provided between the two hydraulic pipes 10, and a push rod 3 is installed at one end of the push rod cavity 11. A preload spring 14 is provided between the push rod 3 and the push rod cavity 11;

[0049] One end of the oil cylinder 9 is pressed against the fixed base 8, and the other end is adapted to the hydraulic pipe 10 and fixedly connected to the push rod cavity 11; the push rod cavity 11 is located between the two hydraulic pipes 10, and the hydraulic pipe 10 is fixed and sealed to the oil cylinder 9. When the hydraulic oil is pressed into one end of the hydraulic pipe 10, the hydraulic oil pushes the piston in the hydraulic pipe 10 to generate thrust, thereby causing the return spring 2 to press against the upper end connecting plate 1;

[0050] Oil pipes 6 are connected to the two side walls of the oil cylinder 9, and their main function is to store oil. The two oil pipes 6 are fixedly connected to the electromagnetic flow valve 7 at one end corresponding to the oil cylinder 9, and the hydraulic energy is converted into mechanical energy at the appropriate time through the control of the electromagnetic flow valve 7; an electromagnetic flow valve 7 is installed on each oil pipe 6, and there are two in total, and their outer ends are fixedly connected to the two sides of one side wall of the oil cylinder 9 respectively, so that the two electromagnetic flow valves 7 can replenish oil and drain oil to the oil cylinder 9 at the same flow rate. When the set value is reached, the controller controls the electromagnetic flow valve 7. At this time, the amount of oil entering the oil cylinder and the amount of oil draining out of the oil cylinder are the same, so that the amount of oil originally stored in the oil cylinder 9 remains unchanged, thereby ensuring that the position of the guide rod 4 remains unchanged;

[0051] One end of the push rod 3 away from the push rod cavity 11 passes through the upper end connecting plate 1 , and the movement between the push rod 3 and the upper end connecting plate 1 is limited by a stopper.

[0052] In another embodiment of the present application, reference Figure 3 and Figure 4 A pressure sensor is provided on the end face of the guide rod 4 away from the hydraulic pipe 10. There are two pressure sensors 13, which are fixedly connected to the guide rod 4 respectively. Their main function is to monitor the force when the unloading force is applied to ensure the accuracy of the unloading force application.

[0053] In another embodiment of the present application, reference Figure 6 The upper connecting plate 1 and the push rod 3 are clearance-fitted. The push rod 3 is installed in the push rod cavity 11, and the bottom cooperates with the preload spring 14. Its main function is to provide a preload force to the floating end bearing by cooperating with the preload spring 14 when the device is not started, so as to ensure the stability and reliability of the bearing under normal working conditions.

[0054] When the push rod 3 is subjected to axial force, it compresses the return spring 2 and the preload spring 14 and allows them to touch the pressure sensor 13 on the guide rod 4 .

[0055] In another embodiment of the present application, the guide rod 4 is fixedly connected to the piston in the hydraulic pipe 10 and can be extended and retracted to compress and release the return spring 2, thereby achieving the function of adjusting the unloading force.

[0056] In another embodiment of the present application, reference Figure 2 A controller 12 is provided on the side wall of the oil cylinder 9. The controller 12 is fixed to the side wall of the upper connecting plate 1 (oil cylinder 9). Its main function is to electrically connect the compression device, the pressure sensor 13 and the electromagnetic flow valve 7. The controller 12 sends a control signal according to the preset compression accuracy and the compression amount and real-time unloading force transmitted by the pressure sensor 13, and automatically controls the compression and extension of the hydraulic telescopic device.

[0057] In another embodiment of the present application, the reset spring 2 is connected to the guide rod 4 and the upper end connecting plate 1 by a slot, and its main function is to reset the guide rod 4 in the hydraulic telescopic device.

[0058] In another embodiment of the present application, the preload spring 14 is connected to the push rod 3 and the push rod cavity 11 via a slot, and its main function is to achieve preliminary unloading of the outer ring of the floating end bearing.

[0059] In another embodiment of the present application, under the action of the preload spring 14, one end of the push rod chamber 11 rests on the oil cylinder 9. The main function of the push rod chamber 11 is to provide guidance and support for the stable movement of the push rod 3. At the same time, it also supports the function of the preload spring 14 to achieve preload of the floating end bearing.

[0060] In another embodiment of the present application, the electromagnetic flow valve 7 is installed near one end of the oil cylinder 9 and fixed on the oil cylinder 9 .

[0061] Working principle:

[0062] 1) Initial unloading force is applied to the floating end bearing:

[0063] The outer ring of the floating end bearing of this device is not provided with a flange. Therefore, a set of springs is first used to apply an initial preload force to the floating end bearing. By compressing the preload spring 14, it is ensured that the bearing can withstand a certain axial force in the initial state. The initial preload force applied to the floating end bearing helps to provide conditions for the normal operation of the subsequent hydraulic telescopic device.

[0064] 2) The floating end bearing is subjected to axial force and triggers the pressure sensor:

[0065] When the floating end bearing is subjected to axial force, the upper end connecting plate 1 is pushed inward, and this movement causes the upper end connecting plate 1 to touch the pressure sensor 13 on the guide rod 4;

[0066] 3) Signal transmission of pressure sensor 13:

[0067] After the pressure sensor 13 is compressed, it detects the change of the axial force in real time and transmits the pressure signal of this change to the controller 12. The controller 12 processes these signals and responds to them. According to the set control logic, it activates the electromagnetic flow valve 7 control system.

[0068] 4) Control of hydraulic telescopic device:

[0069] The controller 12 controls the electromagnetic flow valve 7 to adjust the working state of the hydraulic system according to the signal of the pressure sensor 13, and provides appropriate oil pressure to the oil cylinder 9. The electromagnetic flow valve 7 controls the flow of oil, thereby controlling the expansion and contraction of the hydraulic pipe 10.

[0070] When the oil cylinder 9 receives oil, the hydraulic pipe 10 begins to extend, controlling the guide rod 4 to press against the upper connecting plate 1 and exerting an axial force in the opposite direction on the floating bearing. This unloads the bearing through the hydraulic expansion and contraction device, reducing the axial load on the thrust bearing. At this time, the extension of the hydraulic expansion and contraction device is proportional to the axial force, thereby accurately controlling the load on the floating bearing.

[0071] 5) Feedback control and fixed state retention and reset:

[0072] Another pressure sensor 13 is mounted on the surface of the guide rod 4 to monitor the pressure applied by the guide rod 4. When the pressure of this pressure sensor 13 reaches a preset response value, the pressure sensor 13 sends a feedback signal to the controller 12. Based on the feedback signal, the controller 12 controls the electromagnetic flow valve 7 to close, stopping the oil supply and maintaining the fixed working state of the oil cylinder 9. At this time, the guide rod 4 always presses against the outer ring of the floating end bearing, ensuring that the bearing operates under a stable load.

[0073] Throughout the entire process, the system automatically adjusts the hydraulic expansion and contraction of the hydraulic expansion mechanism based on the axial force acting on the floating bearing, maintaining the floating bearing load within the ideal range. At the end of each operating cycle, the system automatically resets, releasing the floating bearing load and preparing for the next operating cycle. The hydraulic expansion mechanism automatically releases oil pressure to return to its initial state, ensuring a smooth system startup and minimizing losses. This control ensures that the system operates without human intervention, maintaining long-term stability and efficiency.

[0074] However, in order to prevent the hydraulic telescopic device from applying axial force to the floating end bearing for a long time and causing fatigue damage to it, when the axial force borne by the floating end bearing is lower than its set minimum value, the cylinder 9 will stop working, and the return spring 2 will help the guide rod 4 to reset.

[0075] This device combines a pressure sensor 13, a hydraulic cylinder 9, a hydraulic pipe 10, and an electromagnetic flow valve 7 to form a closed-loop control system. Specifically, it applies an appropriate unloading force to the floating bearing through initial spring preload and precise adjustment of the hydraulic system. Simultaneously, the pressure signal fed back by the pressure sensor 13 controls the hydraulic expansion mechanism to prevent it from constantly pressing against the outer ring of the floating bearing. This ensures that the system automatically adjusts and maintains a stable operating state, thereby achieving precise control of bearing force.

[0076] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic control unloading system for a wind turbine generator set, characterized in that : It includes an oil cylinder (9), one end of the oil cylinder (9) is tightly connected to the fixed base (8), and the other end is in contact with the upper end connecting plate (1) through a return spring (2); The two sides of the oil cylinder (9) away from the end surface connected to the fixed base (8) are fixedly connected to the hydraulic pipe (10), and the hydraulic pipe (10) is provided with a guide rod (4) at one end away from the oil cylinder (9), and a return spring (2) is installed on the guide rod (4); The two side walls of the oil cylinder (9) are connected with oil pipes (6), and an electromagnetic flow valve (7) is installed on the oil pipes (6); A push rod cavity (11) is provided between the two hydraulic pipes (10), a push rod (3) is installed at one end of the push rod cavity (11), and a preload spring (14) is provided between the push rod (3) and the push rod cavity (11); One end of the push rod (3) away from the push rod cavity (11) passes through the upper end connecting plate (1), and movement between the push rod (3) and the upper end connecting plate (1) is limited by a stopper.

2. The hydraulic control unloading system of a wind turbine generator set according to claim 1 is characterized in that A pressure sensor (13) is provided on the end surface of the guide rod (4) away from the hydraulic pipe (10).

3. The hydraulic control unloading system of a wind turbine generator set according to claim 1 is characterized in that The push rod (3) is clearance-fitted with the upper end connecting plate (1).

4. The hydraulic control unloading system for wind turbine generator set according to claim 1 is characterized in that The guide rod (4) is fixedly connected to the piston in the hydraulic pipe (10).

5. The hydraulic control unloading system for wind turbine generator set according to claim 1 is characterized in that A controller (12) is provided on the side wall of the oil cylinder (9).

6. The hydraulic control unloading system for wind turbine generator set according to claim 1 is characterized in that The return spring (2) is connected to the upper end connecting plate (1) and the guide rod (4) via a slot.

7. The hydraulic control unloading system for wind turbine generator set according to claim 1 is characterized in that The preload spring (14) is connected to the push rod (3) and the push rod cavity (11) via a slot.

8. The hydraulic control unloading system for wind turbine generator set according to claim 1 is characterized in that The electromagnetic flow valve (7) is installed near one end of the oil cylinder (9).

9. The hydraulic control unloading system for wind turbine generator set according to claim 8, characterized in that The electromagnetic flow valve (7) is fixed on the oil cylinder (9).

10. The hydraulic control unloading system of a wind turbine generator set according to claim 1, characterized in that Under the action of the preload spring (14), one end of the push rod cavity (11) abuts against the oil cylinder (9).

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