Hydraulic control unloading system of wind generating set

Abstract

The invention 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 invention relates to the technical field of wind power generators, in particular to a hydraulic control unloading system for a wind power generator set. Background Art

[0002] With the increasing attention paid to clean energy around the world, wind power generation has become an important part of the renewable energy sector. As the core equipment for realizing wind energy conversion, the performance of wind turbines directly affects the power generation efficiency, equipment life and maintenance costs of the entire wind farm. However, as the precision core components of the wind turbine main shaft transmission system, bearings are prone to severe spalling of the inner and outer raceways under long-term complex alternating loads, leading to failure of the main shaft system [1-2].

[0003] [1] ZhangLiang, ZhangHao, CaiGuowei. The multiclass fault diagnosis of windturbine bearing based on multisource signal fusion and deep learning generative model [J]. IEEE Transactionson 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 transmission system is much lower than the design life of the whole machine. However, the main shaft system of mainstream doubly-fed wind turbines uses spherical roller bearings (SRB) at both the floating end and the thrust end. The failure rate of these bearings is significantly higher than expected. Within the service life of 6-10 years, the failure rate of thrust bearings in wind turbines with this layout is as high as 20-30%. Therefore, in order to effectively increase the service life of the thrust bearing, it is crucial to reasonably reduce its axial force.

[0006] At present, the research is mainly on passive unloading devices, which are simpler in design and mainly rely on external forces or natural phenomena (such as gravity, springs, etc.) to adjust the bearing load. For example, some wind turbines share the axial load borne by the thrust bearing to the floating end bearing by setting up a special adjustment device.

[0007] Although the existing technology has explored the solution to the problem of excessive axial force on thrust bearings to a certain extent, after the passive unloading device is installed, it is equivalent to always acting on the floating end bearing device, making it always bear the force, which also greatly reduces the service life of the floating end bearing. Therefore, how to simplify the design and improve efficiency while ensuring technical reliability is still a problem that needs to be solved in the current technology. Summary of the invention

[0008] In view of 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 combination of active and passive unloading methods into the main bearing system of the wind turbine generator set, the axial pressure on the thrust bearing can be effectively reduced, thereby increasing its service life and the operating stability of the wind turbine generator set. In view of the existing wind turbine generator set main bearing unloading method, which requires a long period of time to apply a preload force to the floating end bearing, 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, and the precise control of the floating end bearing preload force and force feedback adjustment can be achieved through the application of a reset spring, a preload spring, a hydraulic telescopic device, a pressure sensor, an electromagnetic flow valve and a controller. At the same time, the device is also easy to install and maintain, and can significantly improve the overall operating stability of the wind turbine generator set.

[0009] To achieve the above object, 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 through 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 a guide rod is provided at one end of the hydraulic pipe away from the oil cylinder, and a return spring is installed on the guide rod;

[0011] The two side walls of the oil cylinder are connected with 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 stopper.

[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-matched 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 abuts against the oil cylinder.

[0023] Advantages of the present invention:

[0024] 1)Automated preload adjustment

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

[0026] 2) Accurate unloading force response control

[0027] The pressure sensor is used to monitor the unloading force applied by the unloading system in real time, and the pressure signal of the pressure sensor on the guide rod is transmitted to the main controller, so that the hydraulic expansion device can accurately respond and apply unloading force to the floating end bearing, and can also adjust the force applied by the top plate to the floating end bearing. This precise control helps to maintain the smooth operation of the system and avoid damage to the bearing due to excessive or insufficient pressure.

[0028] 3) Effective implementation of unloading function

[0029] By controlling the extension and retraction of the hydraulic expansion device, when the axial force reaches the set value, the appropriate reaction force can be automatically applied to the floating end bearing, thereby effectively realizing the unloading function. This technology not only effectively reduces the load on the floating end 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 to automatically maintain the fixed working state of the hydraulic telescopic 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 telescopic 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 telescopic device.

[0032] 5) Simplified structural design

[0033] The present invention adopts the linkage control of the hydraulic expansion device and the pressure sensor, does not require complex mechanical adjustment devices or manual adjustment components, and greatly simplifies the system structure. The 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] The 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 failure 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 A structural schematic diagram of a hydraulic control unloading system for a wind turbine generator set provided by the present invention;

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

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

[0041] Figure 4 A side view of a hydraulic pipe provided by the present invention;

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

[0043] Figure 6 A cross-sectional view of a push rod cavity and a push rod provided by the present invention;

[0044] Among them: upper end connecting plate 1, return spring 2, push rod 3, guide rod 4, stopper 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0046] The technical solution of the present invention is mainly used for axial unloading of the main shaft system in a wind turbine generator set, especially to solve the problem that the axial force generated by the rotation of the wind wheel during the operation of the wind turbine generator set has an adverse effect on the working life of the thrust bearing. However, the present invention applies a certain unloading force to the floating end bearing, so that the floating end bearing bears part of the axial load and thus achieves effective axial unloading, thereby reducing the excessive axial force borne by the thrust bearing during operation, and can also monitor the axial force borne by the floating end bearing in real time, and feedback the signal of the controller through the pressure sensor, thereby controlling the electromagnetic flow valve to make the hydraulic preload device extend forward to apply a certain unloading force to the floating end bearing, thereby avoiding the premature failure of the floating end bearing due to excessive axial load. At the same time, the present invention can also effectively extend the operating life of the thrust bearing, and also avoid the premature wear and failure of the thrust bearing due to excessive axial force. Through the application of this technical solution, the operating stability of the wind turbine generator set can be significantly improved, the maintenance cost can be reduced, the service life of the thrust bearing can be extended, and the economic benefits and reliability of the wind turbine generator set can be improved.

[0047] like Figure 1-Figure 6 As shown, this embodiment provides a hydraulic control unloading system for a wind turbine generator set, including 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 connected to the upper connecting plate 1 through the reset 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 (that is, 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 of the fixed base 8 are fixedly connected with the hydraulic pipe 10, and a guide rod 4 is provided at one 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, 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;

[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 chamber 11; the push rod chamber 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 port of the hydraulic pipe 10, the hydraulic oil will push 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 one end of the oil cylinder 9, and the hydraulic energy is converted into mechanical energy at an 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 from the oil cylinder 9 under the same flow rate. When the set value is reached, the controller controls the electromagnetic flow valve 7, and at this time, the amount of oil entering the oil cylinder and the amount of oil draining from 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 surface 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-matched, the push rod 3 is installed in the push rod cavity 11, and the bottom is matched with the preload spring 14; its main function is that when the device is not started, the push rod 3 provides a preload force to the floating end bearing through the cooperation with the preload spring 14 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 abuts against 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, while also supporting 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 the device is not provided with a flange. Therefore, a group of springs are first used to apply a preliminary preload force to the floating end bearing. The preload spring 14 is compressed to ensure that the bearing can withstand a certain axial force in the initial state. The preliminary preload force is applied to the floating end bearing. This preliminary preload force 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 an axial force, the upper end connecting plate 1 is pushed to move 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 the change to the controller 12. The controller 12 processes these signals and responds to them. According to the set control logic, the electromagnetic flow valve 7 control system is activated.

[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 the oil, the hydraulic pipe 10 begins to extend, controlling the guide rod 4 to support the upper end connecting plate 1 and applying an axial force in the opposite direction to the floating end bearing. In this way, the bearing can be unloaded through the hydraulic expansion and contraction device, reducing the axial load borne by the thrust bearing. At this time, the extension amount of the hydraulic expansion and contraction device is proportional to the axial force, thereby accurately controlling the load of the floating end bearing;

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

[0072] Another pressure sensor 13 is installed on the surface of the guide rod 4 to monitor the pressure applied by the guide rod 4. When the pressure of the pressure sensor 13 reaches a preset response value, the pressure sensor 13 sends a feedback signal to the controller 12. The controller 12 controls the electromagnetic flow valve 7 to close according to the feedback signal, stops the oil supply, and maintains the fixed working state of the oil cylinder 9. At this time, the guide rod 4 always supports the outer ring of the floating end bearing to ensure that the bearing works under a stable load.

[0073] During the whole process, the system automatically adjusts the expansion and contraction of the hydraulic expansion device according to the change of the axial force on the floating end bearing, keeping the load of the floating end bearing in the ideal range. After each working cycle, the system automatically resets, releases the load on the floating end bearing, and prepares to enter the next working cycle. The hydraulic expansion device automatically releases the oil pressure to return to the initial state, ensuring that the system can start smoothly and avoid losses. Through this control, the system can maintain stability and efficiency for a long time without manual intervention during operation;

[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] The device forms a closed-loop control system by combining the pressure sensor 13, the oil cylinder 9, the hydraulic pipe 10 and the electromagnetic flow valve 7. Specifically, it applies appropriate unloading force on the floating end bearing through the preliminary spring preload and the precise adjustment of the hydraulic system. At the same time, the pressure signal fed back by the pressure sensor 13 can also control the hydraulic expansion device to prevent it from always pressing against the outer ring of the floating end bearing, which also ensures that the system can automatically adjust and maintain a stable working state, thereby achieving precise control of the bearing force.

[0076] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that 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 comprises an oil cylinder (9), one end of which is tightly connected to a fixed base (8), and the other end of which is in contact with an upper connecting plate (1) via 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 a guide rod (4) is provided at one end of the hydraulic pipe (10) 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 chamber (11) is provided between the two hydraulic pipes (10), a push rod (3) is installed at one end of the push rod chamber (11), and a preload spring (14) is provided between the push rod (3) and the push rod chamber (11); 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.

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-matched with the upper end connecting plate (1).

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

7. The hydraulic control unloading system of a 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 of a 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 of a 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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