A bearing structure for a wind turbine

Abstract

The application discloses a bearing structure for a wind driven generator, which comprises a tower drum, a cabin and a generator, a cabin cooling liquid circulation system is arranged in the cabin, a positioning cabin is arranged in the cabin, a positioning cabin shell is fixed to the inner wall of the generator frame body, a bearing main body and a heat dissipation mechanism are arranged in the positioning cabin, the heat dissipation mechanism comprises a liquid cooling heat dissipation assembly and an air circulation heat dissipation assembly, the liquid cooling heat dissipation assembly is arranged on the bearing outer ring, the air circulation heat dissipation assembly is arranged in the cabin, a clutch mechanism is fixed to one side of the positioning cabin, and a transmission mechanism is used for transmitting power of a main shaft to the air circulation heat dissipation assembly. The cooling liquid of the bearing cooling system is connected with a cabin inner cooling system, so that the equipment occupation is reduced; a cooling groove is arranged, the cooling liquid or cabin outer cooling air is drawn by a negative pressure turbine connected with the main shaft, and then the cooling liquid or the cabin outer cooling air is introduced into the bearing inner ring to be cooled; and a plurality of cooling systems are operated according to the situation, so that the operation cost of the equipment is saved.

Description

Technical Field

[0001] This invention relates to the field of wind turbine components, specifically a bearing structure for wind turbines. Background Technology

[0002] A wind turbine is an electrical device that converts wind energy into mechanical motion, which drives a generator to operate and ultimately outputs electrical current. A wind turbine typically includes a rotor, generator, directional control unit, tower, controller, speed limiting safety mechanism, and energy storage device. The rotor rotates under the influence of wind, converting the kinetic energy carried by the wind into the rotational mechanical energy of the rotor shaft. The generator's main shaft rotates under the drive of the rotor shaft, cutting magnetic field lines and generating electricity.

[0003] Bearings used in the main shaft of wind turbine generators consist of an inner ring and an outer ring, and are commonly classified as rolling bearings or sliding bearings. During power generation, friction generates heat, and the resulting temperature rise affects the bearing's thermal expansion rate, which in turn affects the bearing clearance. In direct-drive wind turbine generators, the generator's air clearance primarily depends on the bearing clearance, meaning the bearing clearance affects power generation efficiency. Furthermore, the bearing clearance has a significant impact on its lifespan; therefore, it must be controlled within a certain range. By controlling the temperature of the bearing's inner ring to maintain its clearance within a specific range, its reliability and lifespan can be improved.

[0004] During the operation of wind turbine generators, if the heat generated by the bearings cannot be dissipated effectively and promptly, the internal temperature of the bearings will gradually rise. On the one hand, excessively high temperatures will cause a decrease in lubricating oil viscosity. Taking rolling bearings as an example, the oil film thickness between the rolling elements and the inner and outer raceways will decrease, potentially leading to tempering, burning, pitting, and surface peeling of internal bearing components. On the other hand, wind turbine generator bearings have large radial dimensions, and the inner ring, outer ring, and cage will experience significant geometric displacement due to thermal deformation, resulting in substantial internal stress. Existing bearing cooling systems typically use air as the cooling medium, which has low cooling efficiency and occupies a large space.

[0005] There are many electronic and mechanical components in the hub and nacelle that generate heat, such as the pitch system, yaw motor, nacelle cabinet, and frequency converter cabinet. If the heat cannot be dissipated in time, excessively high hydraulic oil temperatures will reduce the viscosity of the hydraulic oil, leading to increased hydraulic pump unloading and reduced output. Excessive temperatures will also affect the lifespan of conduits and seals. Current technologies reduce temperature by flowing coolant or airflow through the bearing stator, but this cannot adjust the cooling method according to different speeds. The continuous operation of the cooling system is costly, and air cooling is affected by the nacelle environment, with its effectiveness significantly decreasing at high temperatures. A bearing structure is needed that can adjust to different operating conditions of the generator set, selecting the appropriate cooling method for the current operating state. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a bearing structure for a wind turbine generator. The wind turbine generator set includes a tower, a nacelle, and a generator. The nacelle is equipped with a nacelle coolant circulation system and a positioning compartment. The outer shell of the positioning compartment is fixed to the inner wall of the generator frame. The bearing body and heat dissipation mechanism are installed in the positioning compartment. The heat dissipation mechanism includes a liquid cooling component and an air circulation cooling component. The liquid cooling component is disposed on the outer ring of the bearing, and the air circulation cooling component is disposed inside the nacelle. A clutch mechanism is fixed to one side of the positioning compartment. A transmission mechanism transmits the main shaft power to the air circulation cooling component.

[0007] Preferably, the liquid cooling heat dissipation assembly includes a cooling ring and a cooling pipe, with one end face of the cooling ring fitted and fixed to the outer wall of the bearing outer ring, and a cooling groove provided on the other end face of the cooling ring.

[0008] Preferably, the length of the cooling pipe is at least a portion of the inner circumference of the outer ring of the bearing. The cooling pipe is arranged in a spiral shape, gradually opening from the inside to the outside. The cooling pipe is fixed in the cooling groove. The pipe end connected to the inner ring is the input port, and the pipe end connected to the outer ring is the output port. The input port and the output port are respectively connected to the engine compartment coolant circulation system.

[0009] Preferably, a plurality of cooling pipes and manifolds disposed at both ends of the plurality of cooling pipes converge in parallel into the same input port and output port. The cooling groove is disposed on the side of the cooling ring that fits against the outer ring of the bearing. The cooling ring is fixed between the cooling ring and the side wall of the outer ring of the bearing, and the cooling ring is fixed to the outer ring of the bearing using bolts.

[0010] Preferably, the air circulation heat dissipation assembly includes a bearing inner ring, a guide groove, a side cover plate, a through-hole, a flow hole, and a negative pressure assembly. The inner sidewalls on both sides of the bearing inner ring are provided with curved guide grooves, which are arranged in a semi-circular manner. A through-hole is provided at the bottom of the guide groove. Side cover plates are provided on both sides of the bearing inner ring and are fixedly installed on the two side walls of the bearing inner ring. The flow hole is located at the top of the side cover plate.

[0011] Preferably, the flow hole on the side cover plate near the cooling ring is an inlet hole, used to introduce cooling air into the guide groove to cool the bearing inner ring, and the flow hole on the side cover plate away from the cooling ring is an outlet hole, used to introduce hot air into the positioning chamber and outside the positioning chamber.

[0012] Preferably, the negative pressure assembly includes a fan wheel, a fan shaft, and a power gear. The fan wheel is disposed inside the positioning chamber, near the output port, and the fan shaft is rotatably disposed on the end face of the positioning chamber.

[0013] Preferably, the main shaft of the generator is sleeved on the inner ring of the bearing, and a drive gear is sleeved on the main shaft. The clutch mechanism includes a clutch controller, a clutch shaft, and a transmission gear set. The clutch controller is fixedly installed in the generator compartment to control the clutch shaft to slide to a set position. The transmission gear set is sleeved on the clutch shaft. The transmission gear set includes an input gear and an output gear. The input gear meshes with the drive gear, and the output gear meshes with the power gear.

[0014] Preferably, the outer ring and inner ring of the bearing are provided with a plurality of temperature sensors for real-time temperature monitoring.

[0015] Preferably, the cooling medium flowing out of the cabin coolant circulator flows into the inlet of the liquid cooling heat dissipation component through the cooling pipe, and the other path flows through the transmission pipe to liquid cool the heat-generating components in the cabin. After the two cooling media have completed cooling, they flow back into the cabin coolant circulator.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: the coolant of the bearing cooling system is connected to the cooling system inside the engine compartment, reducing equipment occupation; the air cooling of the inner bearing fully utilizes the cooling effect of the coolant, achieving cooling of both the outer and inner rings of the bearing; the inner ring of the bearing is provided with cooling grooves, and depending on the situation, coolant or cooling air from outside the engine compartment is drawn into the inner ring of the bearing by a negative pressure turbine connected to the main shaft for heat dissipation; the operation of the air cooling mechanism of the inner ring of the bearing is controlled by a clutch device, reducing losses and enabling multiple cooling systems to operate individually or in combination as needed, saving equipment operating costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be discussed below. Obviously, the technical solutions described in conjunction with the accompanying drawings are only some embodiments of the present invention. For those skilled in the art, other embodiments and their accompanying drawings can be obtained based on the embodiments shown in these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of a bearing structure for a wind turbine generator according to the present invention.

[0019] Figure 2 This is a schematic diagram of the internal heat dissipation structure of a bearing structure for a wind turbine generator according to the present invention.

[0020] Figure 3 This is a schematic diagram showing the relative positions of the air-cooled heat dissipation mechanism of a bearing structure for a wind turbine generator according to the present invention.

[0021] Figure 4 This is a schematic diagram showing the location of the liquid cooling mechanism of a bearing structure for a wind turbine generator according to the present invention.

[0022] Figure 5 This is a schematic cross-sectional view of the bearing installation state of a bearing structure for a wind turbine generator according to the present invention.

[0023] Figure 6 This is a schematic diagram of the front structure of the inner bearing of a wind turbine bearing structure according to the present invention.

[0024] Figure 7 This is a schematic diagram of the back structure of the inner bearing of a wind turbine bearing structure according to the present invention.

[0025] Figure 8 This is a schematic cross-sectional view of the inner bearing structure of a bearing structure for a wind turbine generator according to the present invention.

[0026] Figure 9 This is a schematic diagram of the inner bearing structure guide groove of a bearing structure for a wind turbine generator according to the present invention.

[0027] In the diagram: 1-Positioning chamber, 2-Main shaft, 3-Bearing inner ring, 31-Guide groove, 32-Pass through port, 33-Side cover plate, 34-Inlet hole, 35-Outlet hole, 36-Heat dissipation fins, 4-Bearing outer ring, 41-Cooling ring, 42-Cooling pipe, 43-Input port, 44-Output port, 45-Clamp, 5-Clutch controller, 6-Fan wheel, 61-Fan shaft, 62-Power gear, 7-Clutch shaft, 71-Input gear, 72-Output gear, 73-Drive gear. Detailed Implementation

[0028] The technical solutions of various 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 described in 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.

[0029] The embodiments of this invention are based on wind turbine generator sets, which include a tower, a nacelle, a hub with wind turbine blades, a generator, and bearings. The nacelle is located at the top of the tower, the hub is located at the front end of the nacelle, and the generator is housed inside the nacelle. The hub is connected to the generator's main shaft 2 via a transmission connection. Each bearing includes an outer bearing ring 4 and an inner bearing ring 3, and the hub rotates via the bearing. For internal rotor type wind turbine generator sets, the outer bearing ring 4 is connected to the generator's stator, and the inner bearing ring 3 is connected to the generator's rotor. A conventional nacelle coolant circulation system is provided within the nacelle.

[0030] Based on such Figures 1 to 9 The bearing structure for a wind turbine generator of the present invention includes: a positioning compartment 1, which is fixedly disposed inside the generator, and the outer shell of the positioning compartment 1 is fixed to the inner wall of the generator frame. The bearing body and heat dissipation mechanism are installed inside the positioning compartment 1; the heat dissipation mechanism includes a liquid cooling heat dissipation component disposed on the outer ring 4 of the bearing; the heat dissipation mechanism also includes an air circulation heat dissipation component disposed inside the nacelle; a clutch mechanism fixed to one side of the positioning compartment 1; and a transmission mechanism that transmits power from the main shaft 2 to the air circulation heat dissipation component.

[0031] The liquid cooling heat dissipation component is connected to an external radiator via a cooling medium transmission pipeline, and the outlet of the liquid cooling heat dissipation component is connected to the inlet of the external radiator via the same pipeline, forming a cooling medium circulation loop. The cooling medium transmission pipeline includes a cooling pipe 42.

[0032] It should be noted that the "liquid cooling" referred to in this invention refers to cooling using a liquid cooling medium.

[0033] The existing technology uses an in-cabin liquid cooling system to liquid cool heat-generating components within the motor compartment. This invention utilizes the cooling medium of the aforementioned in-cabin liquid cooling system. Specifically, the cooling medium flowing from the external radiator of the in-cabin liquid cooling system is used not only to liquid cool heat-generating components within the motor compartment but also to liquid cool the bearing, simultaneously providing non-contact circulating heat dissipation to the inner ring 3 of the bearing. The location of the liquid cooling heat dissipation component is not limited to the outer surface of the outer ring 4 of the bearing; it can absorb heat simply by being attached to the outer ring of the bearing.

[0034] In this embodiment, the liquid cooling heat dissipation assembly includes a cooling ring 41 and a cooling pipe 42. The outer surface of the cooling ring 41 is a smooth plane, and the cooling ring 41 is annular. One end face of the cooling ring 41 is fixed to the outer wall of the bearing outer ring 4, and the other end face of the cooling ring 41 is provided with a cooling groove for placing and fixing the cooling pipe 42. The length of the cooling pipe 42 is at least a portion of the inner circumference of the bearing outer ring 4. The cooling pipe 42 is spirally arranged from the inside to the outside in a vortex shape, and the outer wall of the cooling pipe 42 is fixed in the cooling groove by a clamp 45. The pipe port of the cooling pipe 42 connected to the inner ring is the inlet 43, and the pipe port connected to the outer ring is the outlet 44. The inlet 43 and the outlet 44 are respectively connected to the engine compartment coolant circulation system.

[0035] Additionally, the cooling ring 41 may include a plurality of cooling pipes 42 separated from each other and manifolds disposed at both ends of the plurality of cooling pipes 42, so as to remove heat by means of a cooling medium flowing in the cooling ring 41. That is, the number of cooling pipes 42 may be multiple and converge in parallel into the same inlet 43 and outlet 44, but is not limited thereto. The cooling groove may also be disposed on the side of the cooling ring 41 that is in contact with the outer ring 4 of the bearing. The cooling ring 41 may be fixed between the cooling ring 41 and the side wall of the outer ring 4 of the bearing, and the cooling ring 41 may be fixed to the outer ring 4 of the bearing with bolts, but is not limited thereto.

[0036] The air circulation cooling assembly includes a bearing inner ring 3, a guide groove 31, a side cover plate 33, a through-hole 32, a flow hole, and a negative pressure assembly. The inner walls of both sides of the bearing inner ring 3 are provided with curved guide grooves 31, which are arranged in a semi-circular manner. The bottom of each guide groove 31 has a through-hole 32 for airflow. Side cover plates 33 are provided on both sides of the bearing inner ring 3 and are fixedly mounted on the two side walls of the bearing inner ring 3.

[0037] The side cover plate 33 has a flow hole at its top. Specifically, the flow hole on the side cover plate 33 closest to the cooling ring 41 is an inlet hole 34, used to introduce cooling air into the guide groove 31 to cool the bearing inner ring 3. The flow hole on the side cover plate 33 furthest from the cooling ring 41 is an outlet hole 35, used to guide hot air into the positioning chamber 1 and outside the positioning chamber 1.

[0038] The negative pressure assembly includes a fan wheel 6, a fan shaft 61, and a power gear 62. The fan wheel 6 is disposed inside the positioning chamber 1, near the output port 44. The fan shaft 61 is rotatably mounted on the end face of the positioning chamber 1.

[0039] Preferably, the outer surface of the side cover plate 33 may also be provided with a symmetrically formed heat dissipation fin structure 36. This can achieve conductive heat dissipation, allowing the cooling medium to fully exert its cooling effect.

[0040] Several temperature sensors are installed on the outer ring 4 and the inner ring 3 of the bearing to monitor the temperature of the inner ring 3 in real time, thereby controlling the flow rate of the coolant and the amount of cooling, and achieving temperature control. The temperature sensors are evenly distributed on the sidewall of the outer ring 4 at 90-degree intervals.

[0041] For different operating states of the wind turbine generator set, the temperature sensor mentioned above can be replaced with a speed sensor that detects the rotational speed of the main shaft 2, and the heat dissipation mode can be switched by monitoring the rotational speed of the main shaft 2.

[0042] The main shaft 2 of the generator is sleeved on the inner ring 3 of the bearing. A drive gear 73 is sleeved on the main shaft 2.

[0043] The clutch mechanism includes a clutch controller 5, a clutch shaft 7, and a transmission gear set. The clutch controller 5 is fixedly installed in the generator compartment to control the clutch shaft 7 to slide to a set position. The transmission gear set is sleeved on the clutch shaft 7. The transmission gear set includes an input gear 71 and an output gear 72. The input gear 71 meshes with the drive gear 73, and the output gear 72 meshes with the power gear 62.

[0044] According to the bearing structure of the aforementioned embodiment of the present invention, in the operating state: State 1, when the rotational speed is low, the inner ring 3 of the bearing is a relatively high temperature zone. When the value obtained by the temperature sensor reaches a certain level, the clutch controller 5 controls the clutch shaft 7 to move and engage the output gear 72 with the power gear 62, so that the fan wheel 6 rotates to form a negative pressure state on one side, accelerating the air in the engine compartment to cool the inner ring 3 of the bearing through the guide groove 31 and flow out from the outlet hole 35, thereby achieving local cooling.

[0045] In state 2, as the rotational speed increases, the temperature of the outer ring 4 of the bearing also rises. Cooling medium from the engine compartment coolant circulation system is connected via a controlled valve; part of it enters the engine compartment liquid cooling system, and part enters the cooling pipe 42. The cooling medium flows through the cooling pipe 42, carrying away the heat generated by the bearing. The cooled water then flows out of the cooling pipe 42 and returns to the external radiator along with the cooling water from the engine compartment liquid cooling system for further cooling. The inner ring 3 of the bearing dissipates heat through heat conduction with the outer ring 4 via liquid cooling. At this time, the temperature of the inner ring 3 decreases, the clutch controller 5 disengages from the clutch shaft 7, the power gear 62 disengages, the fan shaft 61 loses power, the fan wheel 6 stops rotating, reducing operating time, increasing service life, and reducing the load on the main shaft 2.

[0046] In state 3, when the set temperature of the generator main shaft 2 exceeds the set value, the clutch controller 5 is reactivated to control the clutch shaft 7 to move and re-engage the output gear 72 with the power gear 62. This causes the fan wheel 6 to rotate, creating a negative pressure state on one side, which accelerates the air in the engine compartment. The air is then cooled by the airflow through the guide groove 31 and flows out through the outlet hole 35. The low-temperature gas near the cooling pipe 42 is drawn into the guide groove 31, achieving a combined cooling effect of direct convection and heat conduction on the bearing inner ring 3, providing sufficient cooling.

[0047] According to an embodiment of the present invention, the bearing mechanism can achieve mixed cooling of the inner bearing ring 3 and the outer bearing ring 4 according to different operating states of the wind turbine generator set. Combining the nacelle cooling with the cooling mechanisms of the inner and outer bearing rings, and activating the appropriate cooling method when needed, helps to extend the service life of the equipment, reduce operating costs, and save space for installation equipment.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims, not by the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A bearing structure for a wind turbine generator, the wind turbine generator set including a tower, a nacelle and a generator, wherein the nacelle is equipped with a nacelle coolant circulation system, characterized in that: It also includes a positioning compartment (1), the outer shell of which is fixed to the inner wall of the generator frame. The bearing body and heat dissipation mechanism are installed inside the positioning compartment (1). The heat dissipation mechanism includes a liquid cooling heat dissipation component and an air circulation heat dissipation component. The liquid cooling heat dissipation component is located on the outer ring (4) of the bearing. The liquid cooling heat dissipation component includes a cooling ring (41) and a cooling pipe (42). One end face of the cooling ring (41) is attached to and fixed to the outer wall of the outer ring (4) of the bearing. The other end face of the cooling ring (41) is provided with a cooling groove. The air circulation heat dissipation component is located inside the engine compartment. The length of the cooling pipe (42) is at least a portion of the inner circumference of the outer ring (4) of the bearing. The tube (42) is arranged in a spiral shape, gradually opening from the inside to the outside. The cooling tube (42) is fixed in the cooling groove. The tube end of the cooling tube (42) connected to the inner ring is the input port (43), and the tube end connected to the outer ring is the output port (44). The input port (43) and the output port (44) are respectively connected to the engine compartment coolant circulation system. The clutch mechanism is fixed on one side of the positioning compartment (1). The transmission mechanism transmits the power of the main shaft (2) to the air circulation heat dissipation assembly. The air circulation heat dissipation assembly includes the bearing inner ring (3), the guide groove (31), the side cover plate (33), the through port (32), the flow hole and the negative pressure assembly. The inner walls on both sides of the bearing inner ring (3) are provided with curved guide grooves (31), which are arranged in a semi-circular manner. The bottom of the guide grooves (31) is provided with a through-hole (32). Side cover plates (33) are provided on both sides of the bearing inner ring (3). The side cover plates (33) are fixedly arranged on both sides of the bearing inner ring (3). The flow holes are provided on the top of the side cover plates (33). The flow holes on the side cover plates (33) near the cooling ring (41) are inlet holes (34) for introducing cooling air into the guide grooves (31) to cool the bearing inner ring (3). The flow holes on the side cover plates (33) away from the cooling ring (41) are... The hole is an outlet hole (35) used to introduce hot air into the positioning chamber (1) and outside the positioning chamber (1). The negative pressure assembly includes a fan wheel (6), a fan shaft (61) and a power gear (62). The fan wheel (6) is located inside the positioning chamber (1) near the output port (44). The fan shaft (61) is rotatably located on the end face of the positioning chamber (1). The main shaft (2) of the generator is sleeved on the inner ring (3) of the bearing. A drive gear (73) is sleeved on the main shaft (2). The clutch mechanism includes a clutch controller (5), a clutch shaft (7) and a transmission gear set. The clutch controller (5) is fixedly located inside the generator compartment to control the clutch shaft (7) to slide to a set position.The clutch shaft (7) is fitted with the transmission gear set, which includes an input gear (71) and an output gear (72). The input gear (71) meshes with the drive gear (73), and the output gear (72) meshes with the power gear (62).

2. The bearing structure for a wind turbine generator according to claim 1, characterized in that: A plurality of cooling pipes (42) and manifolds disposed at both ends of the plurality of cooling pipes (42) are connected in parallel to the same inlet (43) and outlet (44). The cooling groove is disposed on one side of the cooling ring (41) that fits against the outer ring (4) of the bearing. The cooling ring (41) is fixed between the cooling ring (41) and the side wall of the outer ring (4) of the bearing. The cooling ring (41) is fixed to the outer ring (4) of the bearing using bolts.

3. The bearing structure for a wind turbine generator according to claim 2, characterized in that: Several temperature sensors are provided on the outer ring (4) and inner ring (3) of the bearing to monitor the temperature in real time.

4. The bearing structure for a wind turbine generator according to claim 3, characterized in that: The cooling medium flowing out of the cabin coolant circulator flows into the inlet of the liquid cooling heat dissipation component through the cooling pipe (42) and into the cabin coolant circulator through the transmission pipe. After cooling is completed, the two cooling media flow into the cabin coolant circulator.

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