A centrifugal pitch structure for wind turbines

Abstract

This invention belongs to the technical field of wind power generation equipment, and particularly relates to a centrifugal pitch control structure for a wind turbine. The invention provides a centrifugal pitch control structure for a wind turbine, which, by setting pitch control actuators and synchronization components on the hub housing, achieves the following: 1. Radial centrifugal outward load is absorbed and transmitted to the hub housing by the guide structure in the pitch control actuator, and the pitch shaft only rotates around its own axis without generating radial displacement, eliminating the coupling interference between pitch control action and centrifugal outward force; 2. The synchronization component within the enclosed cavity forms a mechanical closed-loop linkage between the pitch control actuators, forcing each blade to maintain angular synchronization. The entire structure relies solely on the physical balance between centrifugal force and elastic restoring force to achieve passive adaptive pitch control.

Description

Technical Field

[0001] This invention belongs to the technical field of wind power generation equipment, and particularly relates to a centrifugal pitch structure for a wind turbine generator. Background Technology

[0002] As the core equipment for converting wind energy into electrical energy, wind turbines utilize pitch control technology to regulate aerodynamic power and limit maximum speed in order to cope with drastic fluctuations in natural wind speed and prevent overspeed damage. Currently, wind turbine pitch systems are mainly divided into active pitch systems (such as electric or hydraulic pitch) that rely on external power sources and passive centrifugal pitch systems that rely on their own rotational inertia. Compared to the disadvantages of active pitch systems, such as complex structure and high maintenance costs, passive centrifugal pitch structures directly utilize the centrifugal force generated by the rotation of the wind turbine as a power source, providing a purely mechanical response without the need for external energy input or complex electrical control. This results in significant advantages such as simplified structure, timely response, and reliable operation, making it widely used in various small and medium-sized wind turbines and off-grid wind turbines.

[0003] For example, Chinese invention patent with publication number CN101699061B and publication date of November 7, 2012 discloses a centrifugal pitch structure for a wind turbine. In this structure, the blade shaft is fitted with a sleeve seat, and a spiral groove is provided on the circumferential surface of the blade shaft, which is also fitted with a compression spring. When the wind speed increases, the blade itself is thrown outward as a centrifugal mass block. The spiral groove on the blade shaft slides relative to the spiral bearing, causing the blade shaft to slide outward while rotating outward, thereby changing the angle of attack.

[0004] However, this centrifugal pitch control structure still has at least the following shortcomings in actual use, which are the technical problems that this invention aims to solve: 1. When the blades change pitch, the blade shaft and the entire blade assembly slides radially outward, which not only changes the rotation radius of the wind turbine and affects aerodynamic stability, but also the huge centrifugal pull from the outward swing of the blades is entirely borne by the main bearing and the helical groove mating surface. Under continuous high-frequency alternating loads, the helical drive surface is prone to wear and breakage, posing a high risk of mechanical failure; 2. Each blade relies solely on its own centrifugal force and spring to perform pitch control in isolation, lacking mandatory mechanical synchronization constraints between the pitch control components. Under complex gust wind shear conditions, the inconsistent deflection angles of the blades can easily cause aerodynamic imbalance in the wind turbine.

[0005] Therefore, in summary, there is an urgent need for a new type of centrifugal pitch control structure for wind turbines that can avoid radial movement of the blade shaft during pitch control and maintain consistent pitch angles between blades. Summary of the Invention

[0006] This invention provides a centrifugal pitch control structure for wind turbines. By setting pitch control actuators and synchronization components on the hub housing, the following are achieved: 1. The radial centrifugal outward load is absorbed and transmitted to the hub housing by the guide structure in the pitch control actuator, and the pitch shaft only rotates around its own axis without generating radial displacement, thus eliminating the coupling interference between the pitch control action and the centrifugal outward force; 2. The synchronization component in the enclosed cavity forms a mechanical closed-loop linkage between the pitch control actuators, forcing each blade to maintain angular synchronization. The entire structure achieves passive adaptive pitch control solely by relying on the physical balance between centrifugal force and elastic restoring force.

[0007] The technical solution adopted by the present invention to solve the above problems is: a centrifugal pitch structure for a wind turbine, comprising: a hub shell, which forms a closed cavity inside and has an outer peripheral sidewall, the rotation center line of the hub shell is defined as axial, and the direction perpendicular to the axial direction is defined as radial; a plurality of pitch actuators are circumferentially spaced along the outer peripheral sidewall, each pitch actuator comprising: a pitch shaft rotatably passing through the outer peripheral sidewall and extending outward along the radial direction to connect to the wind turbine blades, and the inner end of the shaft extending into the closed cavity; a radial guide rod fixed to the outer peripheral sidewall and extending radially; a centrifugal sleeve slidably sleeved on the portion of the pitch shaft extending out of the hub shell and slidingly engaged with the radial guide rod; a limiting stop provided at the outer end of the radial guide rod; and a pre-compressed stop abutting between the limiting stop and the centrifugal sleeve to apply a radially inward restoring force to the centrifugal sleeve. The system includes an elastic reset element and a helical transmission pair disposed between the centrifugal sleeve and the pitch shaft; a synchronization assembly disposed within the enclosed cavity, comprising: an axial limiting rod extending along the axial direction, a synchronization plate slidably engaged with the axial limiting rod and constrained to move only along the axial direction, a shaft connecting plate fixedly disposed at the inner end of each pitch shaft, and a plurality of hinged connecting rods hinged at both ends to the synchronization plate and the corresponding shaft connecting plate, respectively; wherein, when the centrifugal sleeve moves radially outward against the radial inward reset force of the elastic reset element under the action of the centrifugal force generated by the rotation of the hub housing, the helical transmission pair converts the radial movement of the centrifugal sleeve into the rotation of the pitch shaft around its own axis, thereby driving the wind turbine blades to pitch, and the rotation of each pitch shaft drives the corresponding shaft connecting plate to swing, and drives the synchronization plate to translate along the axial direction through each of the hinged connecting rods, so that each pitch shaft maintains angular synchronization.

[0008] A further preferred technical solution is that: the hub housing includes a hollow housing, and a front end cover and a rear end cover respectively enclosed at both ends of the hollow housing along the axial direction, the hollow housing, the front end cover and the rear end cover together enclose the closed cavity, and the outer peripheral sidewall of the hollow housing is provided with a plurality of mounting holes spaced apart circumferentially for the pitch shaft to pass through.

[0009] A further preferred technical solution is that the helical transmission pair includes a helical groove formed on the inner wall of the centrifugal sleeve, and a guide protrusion fixedly disposed on the outer wall of the pitch shaft and slidably engaged in the helical groove.

[0010] A further preferred technical solution is that: the centrifugal sleeve is a stepped sleeve, and the centrifugal sleeve is provided with a shaft hole for the pitch shaft to pass through, a guide hole for the radial guide rod to slide, and a receiving groove communicating with the guide hole to accommodate the elastic reset member; an abutting step surface is formed in the receiving groove, one end of the elastic reset member abuts the abutting step surface, and the other end abuts the limiting stop.

[0011] A further preferred technical solution is that: the length of the radial guide rod is greater than the height of the centrifugal sleeve along the radial direction; the limiting stop includes a baffle disposed at the outer end of the radial guide rod, and a fastener for limiting and fixing the baffle to the radial guide rod.

[0012] A further preferred technical solution is that the fastener is threaded to the end of the radial guide rod, and is used to adjust the position of the baffle along the radial direction to adjust the pre-compression of the elastic reset member.

[0013] A further preferred technical solution is that: at least two axial limiting rods are provided and extend along the axial direction, and the synchronous plate is slidably sleeved through and connected to the outside of each of the axial limiting rods.

[0014] A further preferred technical solution is that the extension direction of the shaft connecting plate is perpendicular to the axis of the pitch shaft, so as to form an eccentric crank driven by the pitch shaft in the closed cavity.

[0015] A further preferred technical solution is that: each of the hinged connecting rods is fixedly provided with a fisheye bearing joint at both ends, and the hinged connecting rods form a multi-degree-of-freedom ball hinge with the synchronization plate and the corresponding rotating shaft connecting plate respectively through the fisheye bearing joints at both ends.

[0016] A further preferred technical solution is that the elastic reset element is a cylindrical helical compression spring.

[0017] The technical effects and advantages of this invention are as follows: 1. A fixed radial guide rod is set up to exclusively bear the high-speed outward sliding of the centrifugal sleeve. Through a non-fixed power conversion with the pitch shaft via a helical transmission pair, the radial centrifugal pull of up to several tons is completely transferred to the guide rod and the hub housing. This ensures that the pitch shaft only bears pure rotational torque during pitch adjustment, avoiding the off-center wear of the support bearings caused by centrifugal pull. This reduces the initial starting frictional resistance of the system, making the wind turbine's response to wind speed changes smoother and more sensitive, and significantly extending the fatigue life of the pitch shaft system under alternating heavy loads. 2. A constraint network composed of axial limit rods, synchronous plates, and hinged connecting rods is used to forcefully close and lock the originally isolated pitch actuators in mechanical space. When any blade... When the blades deflect, all their power is concentrated at the central synchronization plate and forcibly distributed to the remaining blades at the same amplitude. When facing severe conditions such as complex and turbulent gusts of wind shear, local turbulence, or even uneven stress caused by blade icing, this forced synchronization mechanism can ensure that all blades maintain an absolutely consistent windward angle, effectively avoiding severe aerodynamic noise, destructive mechanical resonance, and tower fatigue failure caused by aerodynamic imbalance of the wind turbine. 3. By utilizing the pull-limiting structure of the internal frame, while providing synchronization function, the radial outward movement degree of freedom of the pitch shaft is reliably constrained, preventing it from slipping and detaching in extreme winds. Moreover, it relies on the physical balance between the centrifugal force of the wind turbine's own rotation and the internal elastic restoring force for self-feedback adjustment, eliminating the need for servo motors, hydraulic pump stations, or easily damaged electronic control slip rings, thus simplifying the overall structure of the wind turbine nacelle. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a perspective view of the present invention.

[0020] Figure 2 for Figure 1 A 3D view of the hidden wheel hub shell.

[0021] Figure 3 This is a side cross-sectional view of the present invention.

[0022] Figure 4 for Figure 3 A cross-sectional perspective view.

[0023] Figure 5 This is a top cross-sectional view of the present invention.

[0024] Figure 6This is a three-dimensional structural view of the synchronization component in this invention.

[0025] The meanings of the markings in the diagram are as follows: 1. Hub housing; 2. Pitch actuator assembly; 3. Synchronization assembly; Hollow shell 11, front end cover 12, rear end cover 13, mounting hole 14, pitch shaft 21, radial guide rod 22, centrifugal sleeve 23, limit stop 24, elastic reset part 25, spiral groove 26, guide protrusion 27, axial limit rod 31, synchronization plate 32, shaft connecting plate 33, hinged connecting rod 34, fisheye bearing joint 35; Shaft hole 231, guide hole 232, receiving groove 233, abutting step surface 234, baffle 241, fastener 242. Detailed Implementation

[0026] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0027] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc., mentioned or possibly mentioned in this specification are defined relative to the structure shown in the accompanying drawings. The terms "inner" and "outer" refer to the direction toward or away from the geometric center of a specific component, respectively. These are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0028] As attached Figure 1-6As shown, a centrifugal pitch structure for a wind turbine includes: a hub housing 1, which forms a closed cavity inside and has an outer peripheral sidewall; the rotation center line of the hub housing 1 is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction; a plurality of pitch actuators 2 are circumferentially spaced along the outer peripheral sidewall, each pitch actuator 2 including: a pitch shaft 21 rotatably passing through the outer peripheral sidewall, extending outward along the radial direction to connect to the wind turbine blades, and having its inner end extending into the closed cavity; and a fixed pitch shaft 21. A radial guide rod 22 fixed to the outer peripheral sidewall and extending radially; a centrifugal sleeve 23 slidably sleeved on the portion of the pitch shaft 21 extending out of the hub housing 1 and slidably engaged with the radial guide rod 22; a limiting stop 24 disposed at the outer end of the radial guide rod 22; an elastic reset member 25 sleeved on the radial guide rod 22 and in a pre-compressed state abutting between the limiting stop 24 and the centrifugal sleeve 23 to apply a radially inward reset force to the centrifugal sleeve 23; and a centrifugal sleeve 23 disposed on the outer peripheral sidewall and extending radially along the radial direction; a centrifugal sleeve 23 slidably sleeved on the radial guide rod 22 and abutting between the limiting stop 24 and the centrifugal sleeve 23 to apply a radially inward reset force to the centrifugal sleeve 23; and a centrifugal sleeve 23 slidably sleeved on the outer peripheral sidewall and extending radially along the radial direction; ... A helical drive pair between the centrifugal sleeve 23 and the pitch shaft 21; a synchronization assembly 3, disposed within the enclosed cavity, includes: an axial limiting rod 31 extending along the axial direction; a synchronization plate 32 slidably engaged with the axial limiting rod 31 and constrained to move only along the axial direction; shaft connecting plates 33 respectively fixedly disposed at the inner ends of each pitch shaft 21; and multiple hinged connecting rods 34 with their two ends respectively hinged to the synchronization plate 32 and the corresponding shaft connecting plate 33; wherein, the centrifugal sleeve 23 When the hub housing 1 moves radially outward under the centrifugal force generated by its rotation, overcoming the radial inward reset force of the elastic reset member 25, the helical transmission pair converts the radial movement of the centrifugal sleeve 23 into the rotation of the pitch shaft 21 around its own axis, thereby driving the wind turbine blades to pitch. The rotation of each pitch shaft 21 drives the corresponding shaft connecting plate 33 to swing, and drives the synchronization plate 32 to translate along the axial direction through each hinged connecting rod 34, so that each pitch shaft 21 maintains angular synchronization.

[0029] In this embodiment, the centrifugal pitch structure of the wind turbine includes the hub housing 1, the pitch actuator 2, and the synchronization assembly 3. Specifically, the hub housing 1 is generally a hollow drum-shaped or polygonal cylindrical structure with a closed cavity inside to accommodate components. The hub housing 1 is located at the front end of the wind turbine nacelle, and its rear end face is fixed to the generator rotor or main drive shaft of the wind turbine by flanges and high-strength bolts. Its own rotation center line is coaxial with the wind turbine main shaft, and the direction of this rotation center line is defined as the axial direction, and the radial direction perpendicular to this axial direction is defined as the radial direction. The outer peripheral sidewall of the hub housing 1 serves as the load-bearing base, responsible for the initial transfer of the aerodynamic load of the entire machine to mechanical energy. Specifically, the hub housing 1 includes a hollow housing 11, and a front cover 12 and a rear cover 13 respectively enclosed at both ends of the hollow housing 11 along the axial direction. The hollow housing 11, the front cover 12, and the rear cover 13 together form the closed cavity. Multiple mounting holes 14 are spaced circumferentially on the outer peripheral sidewall of the hollow housing 11 for the corresponding passage of the pitch shaft 21. The hollow housing 11 is a straight cylindrical or drum-shaped casting with openings at both ends. The front cover 12 and the rear cover 13 have a disc-shaped sealing plate structure. The front cover 12 is fixedly fitted onto the windward opening of the hollow housing 11 along the axial direction, and the rear cover 13 is fixedly fitted onto the leeward opening. The edges of the three are fixedly connected by flange faces and countersunk screws arranged in a ring array, together forming a complete closed cavity. The mounting holes 14 are circular holes penetrating the outer peripheral sidewall of the hollow housing 11. The pitch shaft 21 rotates through the corresponding mounting hole 14 via the bearing housing flange. To ensure the internal protection level of the enclosed cavity, an O-ring rubber seal is also provided at the flange mating surface of the hub housing 1 to prevent external moisture and salt spray from entering.

[0030] Furthermore, the pitch actuator 2 is the core component for adjusting the windward angle, and its overall shape is a reciprocating sliding and rotating composite transmission module protruding radially outward. Multiple pitch actuators 2 are arranged in a ring array along the outer peripheral sidewall of the hub housing 1, with a common array size of three, corresponding to a three-bladed wind turbine configuration. Specifically, the pitch actuator 2 includes the pitch shaft 21, the radial guide rod 22, the centrifugal sleeve 23, the limiting stop 24, the elastic reset member 25, and the helical transmission pair. The pitch shaft 21 is rotatably mounted on the outer peripheral sidewall of the hub housing 1 via a combination of deep groove ball bearings and thrust roller bearings, extending radially. Its outer end extends outward and is fixedly connected to the wind turbine blades, while its inner end extends into the enclosed cavity and is fixedly connected to the shaft connecting plate 33. The outer shaft section maintains a fit with the centrifugal sleeve 23. The radial guide rod 22 is a smooth, slender cylindrical shaft arranged parallel to the pitch shaft 21 and extending radially outward. The inner base of the radial guide rod 22 is rigidly fixed to the outer surface of the outer peripheral sidewall of the hollow shell 11 near the mounting hole 14 via a flange base and high-strength bolts. Its outer cylindrical surface forms a sliding fit with the guide hole of the centrifugal sleeve 23, ensuring that the centrifugal sleeve 23 can only move radially linearly. The centrifugal sleeve 23 is a thick-walled metal cylinder with irregularly shaped holes inside. It is radially fitted onto the part of the pitch shaft 21 that extends out of the shell and the outside of the radial guide rod 22. It engages with the radial guide rod 22 through the internal guide hole, and simultaneously engages with the pitch shaft 21 through the inner hole. The limiting stop 24 is a disc-shaped or square solid stop located at the outermost end of the radial guide rod 22 furthest from the outer peripheral sidewall. It is used to prevent the centrifugal sleeve 23 and the elastic reset member 25 from detaching from the guide rod and flying out under extreme centrifugal force, while providing a reverse force support point for the elastic reset member 25. The elastic reset member 25 is a hollow, helical, wound elastic body, preferably a cylindrical helical compression spring, sleeved on the outer cylindrical surface of the radial guide rod 22. Its two ends abut against the inner end face of the limiting stop 24 and the outer end face of the opposing centrifugal sleeve 23, respectively. During initial installation, it is in a pre-compressed deformation state, used to apply a continuous radial inward reset force to the centrifugal sleeve 23, setting the critical speed threshold for pitch start-up, and pushing the centrifugal sleeve 23 back to its original position after the wind speed decreases. The helical drive pair is located between the inner wall surface of the centrifugal sleeve 23 and the outer wall surface of the pitch shaft 21, used to forcibly convert the radial outward displacement of the centrifugal sleeve 23 into the rotational motion of the pitch shaft 21 around its own axis.

[0031] Furthermore, the synchronization component 3 is completely enclosed and hidden inside the closed cavity of the hub housing 1, centrally located on the main axis, to absorb the asymmetrical impact of local gusts on individual blades, and to ensure that all wind turbine blades maintain an absolutely consistent pitch deflection angle under any operating condition through rigid constraints. Specifically, the synchronization component 3 includes the axial limiting rod 31, the synchronization plate 32, the shaft connecting plate 33, and the hinged connecting rod 34. The axial limiting rod 31 is a smooth, long cylindrical straight rod with a finely ground surface, extending parallel to the rotation center line of the hub housing 1, located in the central region of the closed cavity, and its two ends are fixed to the inner walls of the front end cover 12 and the rear end cover 13 by bolts, to restrict the degree of freedom of movement of the synchronization plate 32 within the cavity, allowing it to only perform pure linear translation along the axial direction. The synchronization plate 32 is a polygonal or circular flat plate with multiple peripheral hinge holes and a central guide hole. It is centrally suspended and arranged perpendicular to the axial direction inside the closed cavity. Its central hole is slidably mounted on the axial limiting rod 31. The holes arranged around the periphery of the synchronization plate 32 are connected to one end of each of the hinged connecting rods 34 through hinge pins. This is used to synchronously absorb or distribute axial push-pull displacements outward, forcibly ensuring the consistency of the actions of each pitch actuator 2. The shaft connecting plate 33 is a plate-shaped or rod-shaped structure with an eccentric lever arm. It is located on the innermost end face of the pitch shaft 21 that extends into the closed cavity. Its center is fixedly mounted on the pitch shaft 21 through a spline or flat key. The hole at the extended eccentric end is hinged to the outer end of the hinge connecting rod 34. This is used to convert the fixed-axis rotational motion of the pitch shaft 21 into a spatial arc swing at its outer eccentric hinge point. The hinged connecting rod 34 is a connecting rod entity with hole joints at both ends, and it is obliquely inserted between the synchronization plate 32 and the rotating shaft connecting plate 33. The two ends of the hinged connecting rod 34 are respectively hinged to the periphery of the synchronization plate 32 and the eccentric end of the corresponding rotating shaft connecting plate 33 via pins, to complete the power traction and push-pull transmission between spatial circular motion and axial linear motion. In some modified versions, the middle part of the hinged connecting rod 34 is also designed with an adjusting sleeve containing positive and negative threads for fine-tuning the initial effective length of the connecting rod.

[0032] Finally, the working principle of the centrifugal pitch structure of the wind turbine is as follows: As the ambient wind speed gradually increases, the wind energy captured by the turbine blades increases, causing the rotational speed of the hub housing 1 to continuously increase around the axial direction. The centrifugal sleeve 23 installed on the outer periphery then performs circular motion and generates a radial centrifugal force proportional to the square of the rotational speed. When the rotational speed of the hub housing 1 is lower than the preset speed, the pre-compression reset force of the elastic reset member 25 is greater than the centrifugal force on the centrifugal sleeve 23. The centrifugal sleeve 23 remains in its initial position on the radially inner side, the turbine blades maintain the optimal wind-catching angle, and the system does not produce pitch control. When the rotational speed of the hub housing 1 reaches or exceeds the preset speed, the centrifugal sleeve 23 remains in its initial position on the radially inner side, the turbine blades maintain the optimal wind-catching angle, and the system does not produce pitch control. When the preset speed is exceeded, the centrifugal outward pulling force generated by the centrifugal sleeve 23 overcomes the radial inward restoring force applied by the elastic restoring member 25. The centrifugal sleeve 23 slides linearly outward along the radial guide rod 22, and simultaneously compresses the elastic restoring member 25. During the outward sliding process of the centrifugal sleeve 23, the helical drive pair forms a geometric constraint between the centrifugal sleeve 23 and the pitch shaft 21, converting the radial linear displacement of the centrifugal sleeve 23 into the rotation of the pitch shaft 21 around its own axis. The outer end of the pitch shaft 21 then drives the wind turbine blades to change the pitch angle, realizing aerodynamic unloading and force relief. When any of the pitch shafts 21 rotates around its axis, the shaft connecting plate 33 fixed to its inner end oscillates eccentrically within the enclosed cavity. Its hinge portion, deviating from the axis of the pitch shaft 21, moves along a spatial arc trajectory. This hinge portion, through the connecting rod 34, transmits the push-pull force axially to the synchronizing plate 32, driving the synchronizing plate 32 to translate axially along the axial guide 31. The axial translation of the synchronizing plate 32, in the opposite direction, through the remaining connecting rods 34, forces the remaining sets of shaft connecting plates 33 to oscillate at the same angle, thereby ensuring that even if a single turbine blade experiences abnormal force due to gusts... All the pitch shafts 21 can maintain angle synchronization; when the ambient wind speed drops, the overall speed of the wind turbine decreases, the centrifugal force generated by the centrifugal sleeve 23 decreases, the compressed elastic reset member 25 releases variable force energy, its radial inward reset force is greater than the centrifugal force, pushing the centrifugal sleeve 23 to slide back inward along the radial guide rod 22; the reverse linear sliding passes through the helical transmission pair again, driving the pitch shaft 21 to rotate in the opposite direction, so that the wind turbine blades return to the initial optimal wind-catching angle; at the same time, the synchronization plate 32 also returns to its initial position under the thrust of the reverse connecting rod, and the system enters the standby state, ready to meet the next wind speed fluctuation cycle.

[0033] The beneficial effects of the centrifugal pitch structure of the wind turbine are as follows: First, the radial guide rod 22 is used to support the sliding of the centrifugal sleeve 23, and it is non-fixedly connected to the pitch shaft 21 through the helical transmission pair. This allows the huge radial centrifugal outward force to be completely separated onto the radial guide rod 22 and the outer shell. The pitch shaft 21 only bears pure torque, thereby avoiding the severe bearing wear caused by the centrifugal tension on the pitch shaft 21, and improving the smoothness of the pitch operation and the mechanical life of the whole machine. Second, the synchronization assembly 3, composed of the axial guide 31, the synchronization plate 32, each of the shaft connecting plates 33 and each of the hinged connecting rods 34, forms a mechanical closed-loop linkage between the multiple pitch execution components 2 that originally responded independently. When any blade has a pitch angle deviation trend due to gust wind shear or other operating conditions, the synchronization plate 32 forcibly constrains the other blades to follow synchronously through the hinged connecting rods 34, avoiding wind turbine aerodynamic imbalance and structural vibration caused by inconsistent pitch angles of each blade.

[0034] The helical drive pair includes a helical groove 26 formed on the inner wall of the centrifugal sleeve 23, and a guide protrusion 27 fixedly disposed on the outer wall of the pitch shaft 21 and slidably fitted in the helical groove 26.

[0035] In this embodiment, the spiral groove 26 is a deep spiral groove or inclined groove with a constant lead machined on the inner cylindrical wall of the centrifugal sleeve 23. The guide protrusion 27 is a block-shaped or cylindrical solid, and the root of the guide protrusion 27 is fixedly installed on the outer wall of the middle section of the pitch shaft 21 by interference fit or welding. The top protruding part of the guide protrusion 27 is precisely embedded in the corresponding spiral groove 26, and the sidewalls of the two form a sliding transmission fit with planar or line contact. In order to reduce sliding resistance, the guide protrusion 27 can preferably adopt a cam bearing seat structure with embedded needle rollers to achieve rolling friction.

[0036] The centrifugal sleeve 23 is a stepped sleeve. The centrifugal sleeve 23 has a shaft hole 231 through which the pitch shaft 21 passes, a guide hole 232 for the radial guide rod 22 to slide, and a receiving groove 233 that communicates with the guide hole 232 to accommodate the elastic reset member 25. An abutting stepped surface 234 is formed in the receiving groove 233. One end of the elastic reset member 25 abuts against the abutting stepped surface 234, and the other end abuts against the limiting stop member 24.

[0037] In this embodiment, the centrifugal sleeve 23 has three internal cavities of different diameters machined radially from the inside to the outside. The shaft hole 231 penetrates the base of the centrifugal sleeve 23 and is slidably fitted onto the outer wall of the pitch shaft 21. The central axis of the guide hole 232 is parallel to the central axis of the shaft hole 231, and is disposed on the centrifugal sleeve 23, avoiding the shaft hole 231, for inserting the radial guide rod 22. The receiving groove 233 is the radially outward enlarged portion of the guide hole 232, forming a blind-end annular space. The abutting step surface 234 is formed on the annular end face at the junction of the bottom of the receiving groove 233 and the guide hole 232. The inner end of the elastic reset member 25 directly presses against the abutting step surface 234.

[0038] The length of the radial guide rod 22 is greater than the height of the centrifugal sleeve 23 along the radial direction; the limiting stop 24 includes a baffle 241 disposed at the outer end of the radial guide rod 22, and a fastener 242 that limits and fixes the baffle 241 to the radial guide rod 22.

[0039] In this embodiment, the effective physical length of the radial guide rod 22 is greater than the radial height of the centrifugal sleeve 23, and the difference between the two constitutes the safe travel distance for the centrifugal sleeve 23 to slide outward in the radial direction. The baffle 241 is a disc with a central through hole. The central hole of the baffle 241 is fitted onto the outermost end of the radial guide rod 22. The fastener 242 (such as a nut or pin) locks the back of the baffle 241 from the outside, limiting and fixing it so that it cannot fall off. In this embodiment, when the wind turbine is sent to different wind resource areas (such as the Inner Mongolian grassland with high wind speed and the inland hills with low wind speed), in order to match the optimal rated power generation speed of different sites, it is necessary to change the starting trigger threshold of the blade action. Furthermore, the fastener 242 is threaded to the end of the radial guide rod 22 to adjust the position of the baffle 241 along the radial direction, thereby adjusting the pre-compression of the elastic reset member 25. Specifically, the outermost end of the radial guide rod 22 is machined with a certain length of external thread, and the fastener 242 corresponds to a locking nut with internal threads. The fastener 242 and the end of the radial guide rod 22 form a helical relative movement engagement. By tightening the fastener 242, the absolute spatial position of the baffle 241 in the radial direction can be steplessly changed. As the baffle 241 rotates inward or outward, the elastic reset member 25, which is sandwiched between the baffle 241 and the centrifugal sleeve 23, is further compressed or released, changing its static initial deformation (i.e., pre-compression amount), greatly expanding the site adaptability of the same type of fan. Alternatively, the equivalent purpose of changing the pre-compression amount can be achieved by inserting different numbers of open adjusting shims inside the baffle 241.

[0040] At least two axial limiting rods 31 are provided and extend along the axial direction. The synchronous plate 32 is slidably sleeved through and connected to the outside of each axial limiting rod 31.

[0041] In this embodiment, the number of axial limiting rods 31 is at least two (preferably two or three parallel ones). All axial limiting rods 31 extend parallel to the rotation center axis of the hub housing 1 and are evenly distributed across the spatial cross-section. The synchronizing plate 32 is machined with multiple through guide holes through which each of the axial limiting rods 31 passes. The entire surface of the synchronizing plate 32 is penetrated by these spatially arrayed axial limiting rods 31, forming multi-point sliding support. This avoids the circumferential torsion of the synchronizing plate 32, enabling it to maintain extremely high precision linear translation even under severe off-center loads, thus preventing system jamming.

[0042] The extension direction of the shaft connecting plate 33 is perpendicular to the axis of the pitch shaft 21, so as to form an eccentric crank driven by the pitch shaft 21 in the closed cavity.

[0043] In this embodiment, the direction of the plate surface or main extension arm of the shaft connecting plate 33 is defined as being orthogonal to the central axis of the pitch shaft 21. The suspended outer edge of the vertically fixed shaft connecting plate 33 serves as the force output point. The overall shape forms an eccentric crank mechanism within the closed cavity, with the pitch shaft 21 as the center of rotation and the length of the shaft connecting plate 33 as the eccentric radius. When faced with extremely large blade pitch drag torque (such as increased inertia and steep increase in aerodynamic damping due to icing), the longest vertical lever arm of this orthogonal eccentric crank structure can effectively utilize the lever principle to drive the pitch shaft 21 with minimal push and pull force, thereby efficiently converting and amplifying the pure torsional motion of the pitch shaft 21 into an eccentric push and pull displacement at the end. Furthermore, each of the hinged connecting rods 34 is fixedly provided with a fisheye bearing joint 35 at both ends. The hinged connecting rod 34 forms a multi-degree-of-freedom ball joint with the synchronization plate 32 and the corresponding rotating shaft connecting plate 33 respectively through the fisheye bearing joints 35 at both ends. Specifically, the fisheye bearing joint 35 (i.e., rod end joint bearing) is installed and fixed at both ends of the hinged connecting rod 34. The inner ring of the fisheye bearing joint 35 has a section of inner convex spherical surface, and the outer ring has a covering outer concave spherical surface. When the hinged connecting rod 34 is fixed with the synchronization plate 32 and the rotating shaft connecting plate 33 by pin insertion, the fisheye bearing joints 35 at both ends form two multi-degree-of-freedom ball joint pairs. This allows the hinged connecting rod 34 to not only transmit axial tension and compression, but also to adaptively twist and wobble in three-dimensional space like a human joint. This compensates for and absorbs the three-dimensional spatial deviation difference between the arc trajectory and the straight trajectory, fundamentally eliminating the risk of spatial motion lock of the rigid connecting rod.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A centrifugal pitch structure for a wind turbine generator, characterized in that, include: The hub housing has a closed cavity inside and an outer peripheral sidewall. The direction of the rotation center line of the hub housing is defined as the axial direction, and the direction perpendicular to the axial direction is defined as the radial direction. Multiple pitch actuators are circumferentially spaced along the outer peripheral sidewall. Each pitch actuator includes: a pitch shaft that rotatably passes through the outer peripheral sidewall and extends radially outward to connect to the wind turbine blades, with its inner end extending into the enclosed cavity; a radial guide rod fixed to the outer peripheral sidewall and extending radially; a centrifugal sleeve slidably sleeved on the portion of the pitch shaft extending out of the hub housing and slidingly engaged with the radial guide rod; a limiting stop at the outer end of the radial guide rod; an elastic reset member sleeved on the radial guide rod and in a pre-compressed state abutting between the limiting stop and the centrifugal sleeve to apply a radially inward reset force to the centrifugal sleeve; and a helical drive pair disposed between the centrifugal sleeve and the pitch shaft. The synchronization assembly, disposed within the enclosed cavity, includes: an axial limiting rod extending along the axial direction; a synchronization plate that slides with the axial limiting rod and is constrained to move only along the axial direction; a shaft connecting plate that is fixedly disposed at the inner end of each of the pitch shafts; and a plurality of hinged connecting rods that are hinged at both ends to the synchronization plate and the corresponding shaft connecting plate, respectively. When the centrifugal sleeve moves radially outward against the radial inward reset force of the elastic reset member under the centrifugal force generated by the rotation of the hub housing, the helical transmission pair converts the radial movement of the centrifugal sleeve into the rotation of the pitch shaft around its own axis, thereby driving the wind turbine blades to pitch. The rotation of each pitch shaft drives the corresponding shaft connecting plate to swing, and drives the synchronization plate to translate along the axial direction through each hinged connecting rod, so that each pitch shaft keeps the angle synchronized.

2. The wind turbine centrifugal pitch structure according to claim 1, characterized in that, The hub housing includes a hollow housing, and a front end cover and a rear end cover respectively enclosed at both ends of the hollow housing along the axial direction. The hollow housing, the front end cover and the rear end cover together enclose the closed cavity. The outer peripheral sidewall of the hollow housing is provided with a plurality of mounting holes spaced apart circumferentially for the corresponding passage of the pitch shaft.

3. The wind turbine centrifugal pitch structure according to claim 1, characterized in that, The helical drive pair includes a helical groove formed on the inner wall of the centrifugal sleeve, and a guide protrusion fixedly disposed on the outer wall of the pitch shaft and slidably fitted within the helical groove.

4. The centrifugal pitch structure for wind turbine generators according to claim 1, characterized in that, The centrifugal sleeve is a stepped sleeve. The centrifugal sleeve has a shaft hole through which the pitch shaft passes, a guide hole for the radial guide rod to slide, and a receiving groove communicating with the guide hole to accommodate the elastic reset member. An abutting stepped surface is formed in the receiving groove. One end of the elastic reset member abuts the abutting stepped surface, and the other end abuts the limiting stop.

5. The centrifugal pitch structure for a wind turbine generator according to claim 4, characterized in that, The length of the radial guide rod is greater than the height of the centrifugal sleeve along the radial direction; the limiting stop includes a baffle disposed at the outer end of the radial guide rod, and fasteners that limit and fix the baffle to the radial guide rod.

6. The centrifugal pitch structure for a wind turbine generator according to claim 5, characterized in that, The fastener is threaded to the end of the radial guide rod and is used to adjust the position of the baffle along the radial direction to adjust the pre-compression of the elastic reset member.

7. The centrifugal pitch structure for a wind turbine generator according to claim 1, characterized in that, At least two axial limiting rods are provided and extend along the axial direction, and the synchronization plate is slidably sleeved through and connected to the outside of each axial limiting rod.

8. The wind turbine centrifugal pitch structure according to claim 1, characterized in that, The extension direction of the shaft connecting plate is perpendicular to the axis of the pitch shaft, so as to form an eccentric crank driven by the pitch shaft within the enclosed cavity.

9. The centrifugal pitch structure for a wind turbine generator according to claim 8, characterized in that, Each of the hinged links is fixed with a fisheye bearing joint at both ends. The hinged link forms a multi-degree-of-freedom ball hinge with the synchronization plate and the corresponding rotating shaft connecting plate through the fisheye bearing joints at both ends.

10. The wind turbine centrifugal pitch structure according to claim 1, characterized in that, The elastic reset element is a cylindrical helical compression spring.

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