A passive pitch vertical axis wind turbine

Abstract

This invention discloses a passive pitch vertical axis wind turbine, relating to the technical field of vertical axis wind turbines. It includes a main shaft with blade supports mounted on its outer periphery; multiple blades evenly distributed along the circumference of the main shaft; blade limiting baffles fixed on the blade supports; and a blade angle-of-attack adjustment mechanism, including an adjustable tilting slide bar, an elastic element, and centrifugal claw assemblies. Each blade support is hinged with a tilting slide bar; a centrifugal claw assembly is slidably connected to each tilting slide bar; an elastic element is installed between each centrifugal claw assembly and its corresponding tilting slide bar. When the main shaft rotates, it drives the centrifugal claw assemblies to rotate. Under the action of centrifugal force, each centrifugal claw assembly overcomes the elastic damping force of its corresponding elastic element and slides along the length of its corresponding tilting slide bar, thus contacting the blade surface and driving the blade to rotate to change its angle of attack. This invention effectively improves its self-starting capability, low-wind-speed operating efficiency, and wind energy utilization rate.

Description

Technical Field

[0001] This invention relates to the field of vertical axis wind turbine technology, and in particular to a passive pitch vertical axis wind turbine. Background Technology

[0002] Wind energy is a clean energy source and has become one of the pillars of the global power system. Vertical axis wind turbines are a widely used wind power generation device with great development potential.

[0003] Currently, traditional vertical axis wind turbines are mainly used for power supply in urban and community public facilities, and most of them are drag-type turbines. They directly utilize the thrust of wind on the blades and can typically start up at wind speeds of 3-4 meters per second.

[0004] However, this traditional design has obvious drawbacks: First, its blades are non-streamlined solids, and the blades running against the wind will generate negative torque, which will seriously offset the positive torque generated by the blades running with the wind, causing internal friction in the structure and thus prolonging the start-up time; Second, its rotor blades usually adopt a fixed installation angle, which causes the angle of the blades relative to the wind direction to change continuously during the rotation process, resulting in violent and periodic fluctuations in aerodynamics, affecting operating efficiency and stability.

[0005] Therefore, how to provide a passive pitch vertical axis wind turbine that can effectively improve its self-starting capability, low wind speed operating efficiency and wind energy utilization rate is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention proposes a passive pitch vertical axis wind turbine, which aims to solve at least one of the above-mentioned technical problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a passive pitch vertical axis wind turbine, comprising: A main shaft, on the outer periphery of which a blade support is mounted; Multiple blades are evenly distributed around the main rotating shaft and hinged to the end of the blade support away from the main rotating shaft; the hinge axis of each blade is close to its leading edge and is arranged parallel to the main rotating shaft; blade limiting baffles are fixed on the inner side of the blade support corresponding to the multiple blades. A blade angle-of-attack adjustment mechanism includes an adjustable tilting slide, an elastic element, and a centrifugal claw assembly. Each blade on the blade support is hinged to the main shaft, and the tilting direction of each slide is set along the relative direction between the corresponding blade and the main shaft. A centrifugal claw assembly is slidably connected to each slide along its length. An elastic element for providing elastic damping is installed between each centrifugal claw assembly and the corresponding slide. When the main shaft rotates, it can drive the centrifugal claw assembly to rotate. Under the action of the centrifugal force, each centrifugal claw assembly can overcome the elastic damping force of the corresponding elastic element and slide along the length direction of the corresponding swing slide rod to abut against the blade surface of the corresponding blade, thereby driving the blade to rotate to change its angle of attack.

[0009] This invention discloses a passive pitch vertical axis wind turbine. When the ambient wind speed reaches the turbine's minimum starting wind speed, the airflow acts on the blades, driving multiple blades to rotate around the main shaft. At this time, due to the low rotational speed, the centrifugal force is small. The centrifugal claw assembly is located on the side away from the blade limiting baffle. Under the action of aerodynamic force, the blades can freely swing to the maximum angle of attack position defined by the blade limiting baffle. This position allows the blades to generate the maximum starting torque, thus efficiently achieving low-wind-speed self-start. After the wind turbine starts, as the main shaft rotational speed increases, the centrifugal claw assembly overcomes the damping force of the elastic element and slides along the swinging slide bar, generating radial movement. The front end of the centrifugal claw assembly abuts against the blade surface, damping the blade's rotation and applying a restoring torque. This torque passively and continuously reduces the blade's angle of attack, smoothly transitioning it from a large angle of attack at startup to a small angle of attack during operation. This adaptive process ensures that the wind turbine maintains a high wind energy utilization rate across a wide speed range. Because the centrifugal claw assembly is constrained by the swing slide, it can only slide along the length of the swing slide. By adjusting the tilt angle of the swing slide, the radial travel of the centrifugal claw assembly and the magnitude of the resistance pressure on the blade surface can be adjusted under the same rotational speed, thereby adapting to different wind speeds and conditions.

[0010] As a further improvement to the above technical solution, the blade angle of attack adjustment mechanism also includes a rocker arm tilt angle adjustment mechanism; the rocker arm tilt angle adjustment mechanism is mounted on the main rotating shaft and its drive end is connected to multiple rocker slides, and can drive multiple rocker slides to swing synchronously to change the tilt angle.

[0011] The beneficial effects of the above technical solution are: the blade angle of attack adjustment mechanism can synchronously adjust the tilt angle of the swing slide, improving the flexibility and consistency of adjustment.

[0012] As a further improvement to the above technical solution, the rocker arm tilt angle adjustment mechanism includes a drive motor, a central gear, a worm gear, a worm, and a worm wheel; The drive motor is coaxially mounted on the main shaft, and the central gear is coaxially mounted on the drive motor shaft. There are multiple worm gears, worms, and worm wheels. The multiple worm gears are evenly distributed circumferentially around the central gear and are all meshed with and driven by the central gear. The rotation axes of the multiple worm gears are all radially arranged along the main shaft. The multiple worm wheels are arranged one-to-one with the multiple blades and rotatably mounted on the blade support. The lower ends of the multiple swinging slide rods are fixedly connected one-to-one with the multiple worm wheels. The multiple worms are meshed with and driven by the multiple worm wheels. The multiple worm gears are coaxially connected to the multiple worms.

[0013] The beneficial effects of the above technical solution are as follows: To adapt to the average wind speed in different geographical locations or seasons, the swing arm tilt angle adjustment mechanism can infinitely adjust the tilt angle of the swing slide, thereby adjusting the system's response characteristics. During operation, the drive motor is started, driving the central gear to rotate, which in turn drives multiple worm gears to rotate, thus synchronously driving multiple worms to rotate. The rotating worms drive the meshing worm wheels to rotate, thereby changing the initial angle of the swing slide and the preload of the elastic element, ultimately adjusting the operating characteristics of the entire passive pitch system to match the optimal wind conditions.

[0014] As a further improvement to the above technical solution, the blade support is provided with a bearing seat; a wheel axle is coaxially fixed on the worm gear, and the wheel axle is rotatably connected in the shaft hole of the bearing seat; a limiting groove is provided on the inner wall of the shaft hole, and a limiting block is fixed on the outer periphery of the wheel axle. The limiting block is movably embedded in the limiting groove to limit the rotation angle range of the wheel axle, thereby limiting the swing angle range of the swinging slide rod.

[0015] As a further improvement to the above technical solution, the blade support is provided with an arc-shaped slide rail structure; the upper end of the swinging slide rod is slidably connected to the arc-shaped slide rail structure.

[0016] The beneficial effects of the above technical solution are: the arc-shaped slide rail structure is used to stabilize the upper end of the swing slide bar, thereby improving the stability of the wind turbine operation.

[0017] As a further improvement to the above technical solution, the arc-shaped slide rail structure is a circular arc groove; the worm gear is located at the center of the arc of the circular arc groove.

[0018] As a further improvement to the above technical solution, the centrifugal claw assembly includes a slider, a weight box, and claws; the lower end of the swinging slide is hinged to the blade support; the slider is slidably connected to the swinging slide; the elastic element is a spring with one end fixed to the swinging slide and the other end fixedly connected to the slider; the weight box is connected to the side of the slider away from the main rotating shaft and its inner cavity is a mass block receiving cavity; the claws are fixed to the weight box and can abut against the blade surface of the corresponding blade.

[0019] The beneficial effects of the above technical solution are: the slider, the weight box, the claw, and the elastic element together constitute the spring-mass system; the mass block receiving cavity of the weight box can be filled with mass blocks to change the mass configuration of the spring-mass system, thereby allowing the overall inertia to be flexibly adjusted as needed.

[0020] As a further improvement to the above technical solution, the blade limiting baffle and the corresponding blade are arranged radially at intervals along the main rotating shaft. When the blade rotates to a preset swing angle α, the blade limiting baffle can abut against the blade surface of the corresponding blade, thereby restricting the rotation of the corresponding blade.

[0021] The beneficial effects of the above technical solution are as follows: the blade limiting baffle is used to limit the maximum angle of attack position of the blade, which is determined by a preset swing angle α. When the ambient wind speed reaches the minimum starting wind speed of the wind turbine, the blade can swing freely under the action of aerodynamic force. When the inner surface of the blade abuts against the blade limiting baffle, it swings to the maximum angle of attack position. In addition, the blade limiting baffle can also prevent the blade from reducing efficiency or even flipping over when the blade accelerates its rotation.

[0022] As a further improvement to the above technical solution, the preset swing angle α is 40 degrees.

[0023] The beneficial effect of the above technical solution is that when the preset swing angle α is set to 40 degrees, the blade limiting baffle limits the maximum angle of attack formed by the blade swing to 40 degrees.

[0024] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a passive pitch vertical axis wind turbine, which has the following advantages and beneficial effects.

[0025] 1. Self-starting: When starting, the blades can swing freely under the action of airflow, automatically adjust to the optimal angle of attack, generate the maximum starting torque, and realize self-starting at low wind speed.

[0026] 2. Adaptive operation: After startup, the system can passively and smoothly adjust the blade angle of attack. Its inherent damping characteristics can effectively suppress disturbances and ensure continuous and controllable changes in the angle of attack, thereby improving efficiency while ensuring operational stability.

[0027] 3. Overspeed protection: The maximum angle of attack of the blades is limited by the blade limit baffle to prevent efficiency loss and structural risks at high speeds; when the speed increases further, the system will automatically reduce the angle of attack to achieve natural speed limiting.

[0028] 4. Adaptability to different working conditions: The swing arm tilt adjustment mechanism can achieve stepless gear adjustment, and the spring-mass system can change the mass configuration parameters, so that the wind turbine can flexibly adapt to different wind speed environments.

[0029] 5. Dynamic Operational Stability: The spring-mass system provides the blades with rotational speed-dependent elastic recovery. During normal operation, the blade angle of attack quickly stabilizes at a dynamic equilibrium position under the combined action of centrifugal force and spring force, without continuous oscillation. The blade limit baffles only provide extreme limits for startup and overspeed, and do not interfere with the stability of normal operation. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0031] Figure 1 This invention provides a schematic diagram of the overall structure of a passive pitch vertical axis wind turbine.

[0032] Figure 2 A front view schematic diagram of a passive pitch vertical axis wind turbine according to the present invention.

[0033] Figure 3 A top view schematic diagram of a passive pitch vertical axis wind turbine according to the present invention.

[0034] Figure 4 A bottom view of a passive pitch vertical axis wind turbine according to the present invention.

[0035] Figure 5 This invention provides a cross-sectional schematic diagram of a passive pitch vertical axis wind turbine along the main shaft axis (showing the structure of the blade angle of attack adjustment mechanism).

[0036] Figure 6 This invention provides a partial three-dimensional schematic diagram of the blade angle-of-attack adjustment mechanism for a passive pitch vertical axis wind turbine.

[0037] Figure 7 This invention provides a schematic diagram of the structure of a passive pitch vertical axis wind turbine when the leading edge of the blade abuts against the blade limiting baffle.

[0038] In the diagram: 1. Main shaft; 11. Blade support; 111. Shaft seat; 1111. Limiting groove; 112. Arc-shaped slide rail structure; 2. Blade; 21. Blade shaft; 3. Blade angle of attack adjustment mechanism; 31. Swinging slide bar; 32. Elastic element; 33. Centrifugal claw assembly; 331. Slider; 332. Weight box; 3321. Mass block receiving cavity; 333. Claw; 34. Swing bar tilt angle adjustment mechanism; 341. Drive motor; 342. Central gear; 343. Worm gear; 344. Worm; 345. Worm wheel; 3451. Wheel and axle; 3452. Limiting block; 346. Fixed support; 4. Blade limiting baffle. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] According to embodiments of the present invention, such as Figures 1 to 7As shown, a passive pitch vertical axis wind turbine includes: a main shaft 1, multiple blades 2, and a blade angle of attack adjustment mechanism 3.

[0044] A blade support 11 is installed on the outer periphery of the main shaft 1.

[0045] Multiple blades 2 are evenly distributed around the main rotating shaft 1 and are all hinged to the end of the blade support 11 away from the main rotating shaft 1; the hinge shaft of each blade 2 is close to its leading edge and is set parallel to the main rotating shaft 1; blade limiting baffles 4 are fixed on the inner side of the blade support 11 corresponding to the multiple blades 2.

[0046] The blade angle of attack adjustment mechanism 3 includes an adjustable tilting slide bar 31, an elastic element 32, and a centrifugal claw assembly 33; a tilting slide bar 31 is hinged to each blade 2 and the main rotating shaft 1 on the blade support 11, and the tilting direction of each tilting slide bar 31 is set along the relative direction between the corresponding blade 2 and the main rotating shaft 1; a centrifugal claw assembly 33 is slidably connected to each tilting slide bar 31 along its length direction; an elastic element 32 for providing elastic damping is installed between each centrifugal claw assembly 33 and the corresponding tilting slide bar 31.

[0047] When the main shaft 1 rotates, it can drive the centrifugal claw assembly 33 to rotate. Under the action of the centrifugal force, each centrifugal claw assembly 33 can overcome the elastic damping force of the corresponding elastic element 32 and slide along the length direction of the corresponding swing slide bar 31 to abut against the blade surface of the corresponding blade 2, thereby driving the blade 2 to rotate to change its angle of attack.

[0048] In this embodiment, when a passive pitch vertical axis wind turbine is in operation, and the ambient wind speed reaches the minimum starting wind speed of the wind turbine, the airflow acts on the blades 2, driving multiple blades 2 to rotate around the main shaft 1. At this time, due to the low rotation speed, the centrifugal force is very small. At this time, the centrifugal claw assembly 33 is located on the side of the blade limiting baffle 4 away from the blades 2. Under the action of aerodynamic force, the blades 2 can swing freely to a larger angle of attack position limited by the blade limiting baffle 4. This position can enable the blades to generate the maximum starting torque, thereby efficiently achieving low wind speed self-start. After the wind turbine starts, as the rotational speed of the main shaft 1 increases, the centrifugal claw assembly 33, due to centrifugal force, overcomes the damping force of the elastic element 32 and slides along the swing slide bar 31, generating radial movement. The front end of the centrifugal claw assembly 33 abuts against the outer surface of the blade 2, achieving rotational damping of the blade 2 and applying a restoring torque to the blade 2. This torque passively and continuously reduces the angle of attack of the blade 2, allowing it to smoothly transition from the large angle of attack at startup to the small angle of attack during operation. This adaptive process ensures that the wind turbine can maintain a high wind energy utilization rate over a wide range of rotational speeds. Since the centrifugal claw assembly 33 is constrained by the swing slide bar 31, it can only slide along the length of the swing slide bar 31. By adjusting the tilt angle of the swing slide bar 31, the radial travel of the centrifugal claw assembly 33 and the magnitude of the resistance force on the outer surface of the blade 2 under the same rotational speed conditions can be adjusted, thereby adapting to different wind speeds and conditions.

[0049] In some embodiments, the blade angle of attack adjustment mechanism 3 further includes a rocker arm tilt angle adjustment mechanism 34; the rocker arm tilt angle adjustment mechanism 34 is mounted on the main rotating shaft 1 and its drive end is connected to a plurality of swinging slide rods 31, and can drive the plurality of swinging slide rods 31 to swing synchronously to change the tilt angle.

[0050] The blade angle of attack adjustment mechanism 3 can synchronously adjust the tilt angle of the swing slide bar 31, improving the flexibility and consistency of adjustment.

[0051] In some embodiments, the rocker arm tilt adjustment mechanism 34 includes a drive motor 341, a central gear 342, a worm gear 343, a worm 344, and a worm wheel 345; The drive motor 341 is coaxially mounted on the main shaft 1, and the central gear 342 is coaxially mounted on the shaft of the drive motor 341. There are multiple worm gears 343, worms 344, and worm wheels 345. The multiple worm gears 343 are evenly distributed around the central gear 342 and are all meshed with the central gear 342 for transmission. The rotation axes of the multiple worm gears 343 are all arranged radially along the main shaft 1. The multiple worm wheels 345 are arranged one-to-one with the multiple blades 2 and are rotatably mounted on the blade support 11. The lower ends of the multiple swinging slide rods 31 are fixedly connected one-to-one with the multiple worm wheels 345. The multiple worms 344 are meshed with the multiple worm wheels 345 for transmission. The multiple worm gears 343 are coaxially connected with the multiple worms 344 for transmission.

[0052] To adapt to average wind speeds in different geographical locations or seasons, the sway bar tilt adjustment mechanism 34 can infinitely adjust the tilt angle of the sway bar 31, thereby adjusting the system's response characteristics. During operation, the drive motor 341 is started, driving the central gear 342 to rotate, which in turn drives multiple worm gears 343 to rotate, thus synchronously driving multiple worms 344 to rotate. The rotating worms 344 drive the meshing worm wheels 345 to rotate, thereby changing the initial angle of the sway bar 31 and the preload of the elastic element 32, ultimately adjusting the operating characteristics of the entire passive pitch system to match optimal wind conditions.

[0053] Specifically, the lower part of the main shaft 1 has a mounting cavity, the drive motor 341 is coaxially mounted in the mounting cavity of the main shaft 1, and the worm gear 343 is rotatably mounted on the inner peripheral wall of the mounting cavity of the main shaft 1; a fixed support 346 is mounted at the bottom of the blade support 11; the worm 344 is rotatably mounted on the fixed support 346; one end of the worm 344 extends radially along the main shaft 1 and movably passes through its outer wall and is coaxially fixed with the worm gear 343.

[0054] Specifically, the preferred transmission ratio between the worm gear 344 and the worm wheel 345 is 20:1 to 50:1.

[0055] In some embodiments, the blade support 11 is provided with a bearing seat 111; a wheel axle 3451 is coaxially fixed on the worm gear 345, and the wheel axle 3451 is rotatably connected in the shaft hole of the bearing seat 111; a limiting groove 1111 is provided on the inner wall of the shaft hole, and a limiting block 3452 is fixed on the outer periphery of the wheel axle 3451. The limiting block 3452 is movably embedded in the limiting groove 1111 to limit the rotation angle range of the wheel axle 3451, thereby limiting the swing angle range of the swing slider 31.

[0056] Specifically, the lower ends of multiple swing rods 31 are inserted radially into multiple worm gears 345 and fixedly connected to the wheel axle 3451 to improve connection stability. The tilt angle θ of the swing rods 31 is 0-90 degrees.

[0057] In some embodiments, the blade support 11 is provided with an arc-shaped slide rail structure 112; the upper end of the swing rod 31 is slidably connected to the arc-shaped slide rail structure 112.

[0058] The arc-shaped slide rail structure 112 is used to stabilize the upper end of the swing slide bar 31 and improve the stability of the wind turbine operation.

[0059] In some embodiments, the arc-shaped slide rail structure 112 is an arc-shaped slide groove; the worm gear 345 is located at the center of the arc of the arc-shaped slide groove.

[0060] Specifically, the arc-shaped slide rail structure 112 is a quarter-circle arc slide groove.

[0061] In some embodiments, the centrifugal claw assembly 33 includes a slider 331, a weight box 332, and a claw 333; the lower end of the swinging slide bar 31 is hinged to the blade support 11; the slider 331 is slidably connected to the swinging slide bar 31; the elastic element 32 is a spring with one end fixed to the swinging slide bar 31 and the other end fixedly connected to the slider 331; the weight box 332 is connected to the side of the slider 331 away from the main rotating shaft 1 and its inner cavity is a mass block receiving cavity 3321; the claw 333 is fixed to the weight box 332 and can abut against the blade surface of the corresponding blade 2.

[0062] The slider 331, the weight box 332, the claw 333, and the elastic element 32 together constitute the spring-mass system; the mass block receiving cavity 3321 of the weight box 332 can be filled with mass blocks to change the mass configuration of the spring-mass system, thereby flexibly adjusting the overall inertia as needed.

[0063] Specifically, the weight box 332 is equipped with a lid, which is used to open and close the entrance of the mass block receiving cavity 3321.

[0064] In some embodiments, a mass block assembly is also included; the mass block receiving cavity 3321 is a rectangular or circular cavity with an open top, which is closed by a lid. The mass block assembly can be inserted into the mass block receiving cavity 3321 through its open top; the mass block assembly includes multiple cylindrical mass blocks of different diameters, which can be coaxially fitted and nested sequentially, allowing for flexible adjustment of the mass block assembly's mass as needed. The outer periphery of the cylindrical mass block with the largest diameter matches the inner periphery of the mass block receiving cavity 3321. In use, the cylindrical mass blocks are assembled sequentially from largest to smallest diameter, with the number of cylindrical mass blocks selected as needed. After the lid closes the open top of the mass block receiving cavity 3321, the bottom of the lid presses against the top of the mass block assembly, ensuring the mass block assembly is stably installed in the mass block receiving cavity 3321, thus preventing displacement of the mass block assembly during wind turbine rotation and affecting operational stability.

[0065] In some embodiments, the blade limiting baffle 4 and the corresponding blade 2 are arranged radially at intervals along the main rotating shaft 1. When the blade 2 rotates to a preset swing angle α, the blade limiting baffle 4 can abut against the blade surface of the corresponding blade 2, thereby restricting the rotation of the corresponding blade 2.

[0066] The blade limiting baffle 4 is used to limit the maximum angle of attack of the blade 2. The maximum angle of attack is determined by a preset swing angle α. When the ambient wind speed reaches the minimum starting wind speed of the wind turbine, the blade 2 can swing freely under the action of aerodynamic force. When the inner surface of the blade 2 abuts against the blade limiting baffle 4, it swings to the position of the maximum angle of attack. In addition, the blade limiting baffle 4 can also prevent the blade from reducing efficiency or even flipping over when the blade accelerates its rotation.

[0067] In some embodiments, the preset swing angle α is 40 degrees.

[0068] Specifically, the blade support 11 includes multiple upper cantilever supports and multiple lower cantilever supports arranged radially along the main rotating shaft 1. The upper cantilever supports are evenly distributed circumferentially along the main rotating shaft 1, with one end fixed to the outer peripheral wall of the main rotating shaft 1 and the other end serving as the upper hinge end of the blade. Multiple lower cantilever supports are arranged below the upper cantilever supports, with one end fixed to the outer peripheral wall of the main rotating shaft 1 and the other end serving as the lower hinge end of the blade. The upper and lower ends of the blade 2 are rotatably connected to the other ends of the corresponding upper and lower cantilever supports via blade rotating shafts 21. The length direction of the blade 2 is parallel to the main rotating shaft 1. The blade 2 can swing freely within a certain angle range around the blade rotating shaft 21. A blade limiting baffle 4 is fixedly installed at the other end of the upper cantilever support and corresponds to the inner side of the corresponding blade 2, used to limit the maximum swing angle of the blade 2 and prevent excessive overturning. A bearing seat 111 is fixed at the other end of the lower cantilever support and corresponds to the inner side of the corresponding blade 2. An arc-shaped slide rail structure 112 is formed on the lower cantilever support.

[0069] Specifically, there can be two, three, or four blades.

[0070] In some embodiments, the operation of a passive pitch vertical axis wind turbine is as follows: Start-up phase: When the ambient wind speed reaches the minimum start-up wind speed of the wind turbine, the airflow acts on the blades 2, driving the four blades 2 to rotate around the main shaft 1. At this time, due to the low rotation speed, the centrifugal force is very small, and the blades 2 can swing freely to the maximum angle of attack position limited by the blade limiting baffle 4 under the action of aerodynamic force. This position enables the blades to generate the maximum starting torque, thereby efficiently achieving low wind speed self-start.

[0071] Operation and Adaptive Pitch Phase: After the wind turbine starts, as the rotational speed of the main shaft 1 increases, the radial motion of the centrifugal claw assembly 33 due to centrifugal force is transmitted through the swing slide 31 and overcomes the tension of the spring. The claws 333 at the front end of the centrifugal claw assembly 33 abut against the outer surface of the blade 2 to dampen the blade 2, thereby applying a restoring torque to the blade 2. This torque passively and continuously reduces the angle of attack of the blade, allowing it to smoothly transition from the large angle of attack at startup to the small angle of attack during operation. This adaptive process ensures that the wind turbine can maintain a high wind energy utilization rate over a wide range of rotational speeds.

[0072] Overspeed protection and limiting: When the wind turbine speed increases abnormally, the blade limiting baffle 4 prevents the blade 2 from turning too much through mechanical limiting, effectively avoiding the efficiency reduction and structural risks caused by the deterioration of aerodynamic performance, and ensuring the reliability of operation.

[0073] Gear Adjustment Operation: To adapt to average wind speeds in different geographical locations or seasons, the system's response characteristics can be adjusted via the swashplate tilt adjustment mechanism 34. Specifically, the drive motor 341 is started, driving the central gear 342 and worm gear 343 to rotate. The central gear 342 meshes with the worm gears 343 in four directions, and the worm gears 343 are keyed to the worms 344, thereby driving the four worms 344 to rotate synchronously. The rotation of the worms 344 drives the meshing worm wheel 345 to rotate, thus changing the initial angle of the swashplate 31 and the preload of the spring, ultimately adjusting the operating characteristics of the entire passive pitch system to match optimal wind conditions.

[0074] Dynamic stability design: By matching the mass weight, spring stiffness, and damping settings, the system's natural frequency avoids the main excitation source and remains in an overdamped or critically damped state. This ensures that the blade angle of attack decreases continuously and smoothly with increasing speed, with each stable speed corresponding to a unique equilibrium angle of attack, thus eliminating unstable oscillations during operation.

[0075] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0076] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A passive variable-pitch vertical axis wind turbine characterised in that, include: Main shaft (1), with a blade support (11) installed on the outer periphery of the main shaft (1); Multiple blades (2) are evenly distributed around the main rotating shaft (1) and hinged to the end of the blade support (11) away from the main rotating shaft (1); the hinge axis of each blade (2) is close to its leading edge and is arranged parallel to the main rotating shaft (1); blade limiting baffles (4) are fixed on the inner side of the blade support (11) corresponding to the multiple blades (2). The blade angle of attack adjustment mechanism (3) includes an adjustable tilting slide bar (31), an elastic element (32), and a centrifugal claw assembly (33). The blade support (11) is hinged to each blade (2) and the main shaft (1). The swing direction of each swing slide bar (31) is set along the relative direction between the corresponding blade (2) and the main shaft (1). The centrifugal claw assembly (33) is slidably connected to each swing slide bar (31) along its length. The elastic element (32) for providing elastic damping is installed between each centrifugal claw assembly (33) and the corresponding swing slide bar (31). When the main shaft (1) rotates, it can drive the centrifugal claw assembly (33) to rotate. Under the action of the centrifugal force, each centrifugal claw assembly (33) can overcome the elastic damping force of the corresponding elastic element (32) and slide along the length direction of the corresponding swing slide (31) to abut against the blade surface of the corresponding blade (2), thereby driving the blade (2) to rotate to change its angle of attack.

2. A passive variable-pitch vertical axis wind turbine according to claim 1, characterised in that, The blade angle of attack adjustment mechanism (3) further includes a rocker arm tilt angle adjustment mechanism (34); the rocker arm tilt angle adjustment mechanism (34) is mounted on the main rotating shaft (1) and its drive end is connected to multiple rocker slides (31), and can drive multiple rocker slides (31) to swing synchronously to change the tilt angle.

3. A passive variable-pitch vertical axis wind turbine according to claim 2, characterised in that, The rocker arm tilt adjustment mechanism (34) includes a drive motor (341), a central gear (342), a worm gear (343), a worm (344), and a worm wheel (345). The drive motor (341) is coaxially mounted on the main shaft (1), and the central gear (342) is coaxially mounted on the shaft of the drive motor (341); there are multiple worm gears (343), worms (344), and worm wheels (345); the multiple worm gears (343) are evenly distributed around the central gear (342) and are all meshed with the central gear (342) for transmission; the rotation axes of the multiple worm gears (343) are all The main shaft (1) is radially arranged; a plurality of worm gears (345) are arranged and rotatably mounted on the blade support (11) corresponding to a plurality of blades (2); the lower ends of a plurality of swing slide rods (31) are fixedly connected to a plurality of worm gears (345) corresponding to a plurality of blades (2); a plurality of worms (344) are meshed and driven by a plurality of worm gears (345) corresponding to a plurality of worms (345); a plurality of worm gears (343) are coaxially driven by a plurality of worms (344).

4. A passive variable-pitch vertical axis wind turbine according to claim 3, wherein, The blade support (11) is provided with a bearing seat (111); a wheel axle (3451) is coaxially fixed on the worm gear (345), and the wheel axle (3451) is rotatably connected in the shaft hole of the bearing seat (111); the inner wall of the shaft hole is provided with a limiting groove (1111), and a limiting block (3452) is fixed on the outer periphery of the wheel axle (3451). The limiting block (3452) is movably embedded in the limiting groove (1111) to limit the rotation angle range of the wheel axle (3451), thereby limiting the swing angle range of the swinging slide bar (31).

5. A passive pitch vertical axis wind turbine according to claim 3, characterized in that, The blade support (11) is provided with an arc-shaped slide rail structure (112); the upper end of the swing slide rod (31) is slidably connected to the arc-shaped slide rail structure (112).

6. A passive pitch vertical axis wind turbine according to claim 5, characterized in that, The arc-shaped slide rail structure (112) is an arc-shaped slide groove; the worm gear (345) is located at the center of the arc of the arc-shaped slide groove.

7. A passive pitch vertical axis wind turbine according to claim 1, characterized in that, The centrifugal claw assembly (33) includes a slider (331), a weight box (332), and claws (333); the lower end of the swinging slide (31) is hinged to the blade support (11); the slider (331) is slidably connected to the swinging slide (31); the elastic element (32) is a spring with one end fixed to the swinging slide (31) and the other end fixedly connected to the slider (331); the weight box (332) is connected to the side of the slider (331) away from the main rotating shaft (1) and its inner cavity is a mass block receiving cavity (3321); the claws (333) are fixed to the weight box (332) and can abut against the blade surface of the corresponding blade (2).

8. A passive pitch vertical axis wind turbine according to claim 1, characterized in that, The blade limiting baffle (4) and the corresponding blade (2) are arranged radially at intervals along the main rotating shaft (1). When the blade (2) rotates to a preset swing angle α, the blade limiting baffle (4) can abut against the blade surface of the corresponding blade (2), thereby restricting the rotation of the corresponding blade (2).

9. A passive pitch vertical axis wind turbine according to claim 8, characterized in that, The preset swing angle α is 40 degrees.

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