Sandwich-rim and double-layer-blade wind turbine rotor

Abstract

A sandwich-rim and double-layer-blade wind turbine rotor, comprising a rim (1) and a plurality of groups of blades arranged on the circumference of the rim by means of blade brackets (2). The rim (1) is of a sandwich type formed by an inner panel (11), a middle core plate (12) and an outer panel (13), and conical corners are formed at two side edges of the rim (1). Each blade comprises an inner blade (4) and an outer blade (3). A plurality of double-output-shaft pitch control motors (8) are circumferentially and evenly arranged at the middle of a sealed cavity between the inner panel (11) and the outer panel (13) and are each used for driving the inner blade (4) and the outer blade (3) to perform linked pitch control; and by means of reinforcing plates (14) provided inside the rim (1), slings (18) and stay cables (6), the rim (1) is connected to disc-shaped flanges (7) mounted on both sides of a rotor hub (20). The wind turbine rotor effectively utilizes the rim (1) for the arrangement of inner and outer blades, facilitates synchronous control and adjustment of blade pitch, reduces the wind shielding area of the rim (1), improves the torque and working efficiency of the rotor, improves the reliability and structural strength of the rotor, and is suitable for being used in various wind power generation sites.

Description

A sandwich-type rim double-blade wind turbine impeller Technical Field

[0001] The present invention relates to a wind power generation device, in particular to a sandwich-type rim double-blade wind power generator impeller, which is suitable for horizontal axis wind power generators to be used in various wind power generation sites. Background Art

[0002] Currently, the impellers of large, medium, and small horizontal-axis wind turbines, which are widely used and powered by wind energy, mostly utilize a three-blade structure mounted on the hub. While the overall impeller blade area is considerable, the area at the blade tip distal to the central axis is limited, failing to fully utilize the principle of leverage. The torque of the impeller as a whole is low, and the blades are only connected to the hub at the root end. This results in poor mechanical strength, particularly for large and medium-sized single-support structures, which can easily cause blade breakage and low impeller torque. As the capacity of individual units increases, the torque generated by three-blade impellers is low, making it difficult to meet the needs of larger wind turbines. Three-blade impellers also present challenges such as difficulty in blade manufacturing, high costs, and difficulty in transportation and hoisting.

[0003] In response to the problems of poor mechanical strength, great implementation difficulty and poor practicality of existing large and medium-sized wind turbines, the inventors have provided a variety of improved full-blade tip impellers with a truss structure formed by flanges, inclined cables and rims. Among them, the patent document with publication number CN110005575A provides a full-blade tip impeller dual-drive high-efficiency wind turbine, whose impeller structure includes: the inner side of the rim of the full-blade tip impeller is fixedly connected to the double-disc flange at the front end of the main shaft through an inclined cable, and the disc-shaped openings of the double-disc flanges face outward respectively. The impeller adopts a V-shaped rim in cross section, and a sealed cavity formed between the rim and the sealing plate is provided with a pitch motor. The transmission end of the pitch motor is connected to the blade bracket, and the blade bracket is hinged to the blade. The blade bracket slides in the arc-shaped guide rail using a lower end limit slider, and the outside of the rim is hinged with an electric push rod that drives the blade to flip longitudinally. While this improves the efficiency of horizontal-axis wind turbine rotors in utilizing wind energy, it still suffers from the following drawbacks: 1. Due to the V-shaped rim, only one layer of blades can be mounted on the outer edge of the rim, resulting in an insufficient number of blades, resulting in low wind energy utilization efficiency; 2. Adjusting the blade direction is difficult; 3. The V-shaped rim increases the windshield area; and 4. The truss-shaped rim creates significant wind resistance during rotation. Therefore, further improvements and structural optimization are urgently needed to further enhance the reliability and efficiency of the impeller.

[0004] To summarize, the above-mentioned wind turbine impellers generally have the following problems: the rim can only be used to install a layer of blades on the outer edge of the rim, the impeller torque is small, the reliability is poor, the full-tip impeller blade installation space is small, the number of blades is insufficient, the rim is directly connected to the inclined cable instead of being connected at multiple points through multiple slings, the reliability is difficult to guarantee, the implementation is difficult, the cost is high, the efficiency is low, and the manufacturing is difficult. In addition, according to theoretical calculations, the torque generated by the blade tip of the same unit area on the impeller is much greater than that of the middle and root of the blade. Therefore, the impeller of the existing technology is inefficient and does not meet the wind load requirements of high-efficiency wind turbines. Summary of the Invention

[0005] The purpose of the present invention is to provide a sandwich rim double-layer blade wind turbine impeller, which solves the problems that the existing wind turbine impellers and full-tip impellers can only install one layer of blades on the outer edge of the rim, the overall area of ​​the blades is small, the number and reliability are difficult to guarantee, the implementation is difficult, the cost is high, the efficiency is low, the wind resistance of the rim of the truss structure is large when it rotates, and the structure is bulky, as well as the problem of low work efficiency caused by the difficulty in increasing the impeller torque. It more effectively utilizes the sandwich rim to set the double-layer blades inside and outside the rim and the improved rim structure, reduces the windshield area of ​​the rim, and improves the strength and work efficiency of the impeller.

[0006] The technical solution adopted by the present invention is: the sandwich rim double-blade wind turbine impeller includes a rim and a plurality of blades evenly distributed around the rim circumference through a blade bracket. The technical key points are: the rim includes a sandwich rim with sealed edges consisting of an inner panel, a middle core plate and an outer panel, and the edges on both sides of the rim are formed with conical angles. The blades include inner blades and outer blades, the inner blades are arranged outside the inner panel of the rim through a blade bracket, and the outer blades are arranged outside the outer panel of the rim through a blade bracket. The sealed cavity between the inner panel and the outer panel is in the middle. Multiple double-shaft variable-pitch motors are evenly distributed along the circumference. The drive shafts at both ends of the double-shaft variable-pitch motors can pass through the through holes of the inner panel and the outer panel respectively, and be connected to the center of the bottom beam of the blade bracket, so as to drive the inner blades and the outer blades to change the pitch in a linked manner; the limit sliders connected on both sides of the bottom of the blade bracket are arranged in the arc guide rails of the rim panel on the same level, and the inner panel and the outer panel are hinged to the edges of the blade bracket on both sides through the electric push rods that auxiliary supports to push the blades to rotate; the rim is connected to the dish-shaped flanges installed on both sides of the impeller hub through the built-in reinforcement plate through the sling and the inclined cable.

[0007] The reinforcing plates are multiple reinforcing plates fixedly installed between the rim panel and the core plate. The reinforcing plates are connected to one end of the sling. The other end of the sling passes through the inner panel of the rim and is plugged into one end of the inclined cable. The other end of the inclined cable is cross-connected to the two disc-shaped flanges.

[0008] The ball head at the front end of the electric push rod is installed in the ball seats on the edges of both sides of the blade bracket, and the earrings with joint bearings at the tail end of the electric push rod are connected to the earring base on the rim panel at the same level through a pin shaft.

[0009] The inner panel and the outer panel are provided with guide rail mounting plates with flat outer surfaces for mounting the arc-shaped guide rails.

[0010] The present invention has the following advantages and positive effects: since the rim of a sandwich-type rim double-blade wind turbine impeller is made of an inner panel, a middle core panel, and an outer panel, the inner and outer panels are sealed together, and the edges of the rim are formed with tapered angles on both sides, multiple sets of blades can be installed on both the inner and outer panels of the rim through blade brackets, greatly increasing the number of blades provided. The tapered angles on both sides of the rim are formed to change the direction of airflow according to the shape of the resistance body encountered. The taper of the windward surface of the rim has the effect of gathering and guiding wind, which can significantly enhance the wind tunnel effect of the rim. At the same time, the rim structure has the advantages of high strength, simple construction, light weight, and a small windshield area, and improves reliability. The design concept of the present invention is based on the principle of leverage. In particular, the impeller system can rotate about the impeller axis, which is equivalent to a sandwich-type rim double-blade wind turbine impeller with the axis as the fulcrum, the rim radius as the force-saving lever, and multiple small blades evenly distributed inside and outside the rim as the power source. This significantly increases the overall area of ​​the blade tips and improves the impeller torque by leveraging the principle of leverage. Multiple dual-shaft pitch motors are evenly spaced along the circumference of the sealed cavity between the inner and outer panels. The motors' shafts extend through holes in the inner and outer panels, connecting to the center of the blade support's bottom crossbeam, which drives the coordinated pitch of the inner and outer blades. This effectively utilizes the interlayer space between the inner and outer panels to house the dual-shaft pitch motors, enabling synchronized pitching of the inner and outer blades on the wheel rim. Limiting sliders attached to the blade support's bottom side slide within curved guide rails on the same level of the wheel rim panel, providing multiple limiting support points between the blades and the panel and enhancing the stability of the inner and outer blades' rotation. The inner and outer panels are hinged to the blade support's edges via auxiliary support levers that propel the blades, providing both pitch control and blade support while also preventing blades from falling and ensuring their safety. The wheel rim is connected to the disc-shaped flange via internal reinforcement plates via slings and diagonal cables, increasing the wheel rim's load capacity and reliability. To sum up, the use of inner and outer double-layer blade design increases the blade installation space, lowers the starting wind speed, and improves the wind power generation efficiency. The blades are miniaturized and lightweight, which is convenient for manufacturing, transportation, and lifting, greatly reducing the manufacturing cost. The effective use of the rim to set the inner and outer blades makes it easy to synchronously control and adjust the blade pitch, reducing the rim windshield area, improving the impeller torque and working efficiency, increasing the reliability and structural strength of the impeller, and improving safety. It is safe, reliable, and has a reasonable design and can be used in a variety of wind power generation sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described below with reference to the accompanying drawings.

[0012] FIG1 is a schematic structural diagram of an embodiment of the present invention;

[0013] FIG2 is a longitudinal sectional view of FIG1;

[0014] FIG3 is an enlarged view of portion A of FIG2 ;

[0015] FIG4 is an enlarged view of portion B of FIG2 ;

[0016] 5 is a side view of the inner blades and outer blades in the installation state according to an embodiment of the present invention;

[0017] FIG6 is a top view of FIG5;

[0018] FIG7 is a schematic diagram of the overall structure of the present invention in a pitch state;

[0019] FIG8 is a side view of the inner blades and outer blades in a pitch state according to an embodiment of the present invention;

[0020] FIG. 9 is a top view of FIG. 8 .

[0021] Explanation of the serial numbers in the figure: 1 wheel rim, 2 blade bracket, 3 outer blade, 4 inner blade, 5 electric push rod, 6 inclined cable, 7 disc flange, 8 double-shaft pitch motor, 81 transmission shaft, 9 limit slider, 10 curved guide rail, 11 inner panel, 12 core plate, 13 outer panel, 14 reinforcement plate, 15 tapered corner, 16 earring base, 17 ball seat, 18 sling, 19 reinforcement ring, 20 hub, 21 guide rail mounting plate. DETAILED DESCRIPTION

[0022] 1 to 9 , the specific structure of the present invention is described in detail. The present invention is an improvement based on the technical solutions of the “full-tip wind turbine” with publication number CN103147926B and the “full-tip impeller dual-drive high-efficiency wind turbine” with publication number CN110030147A.

[0023] As shown in Figures 1 and 2, a sandwich-type rim double-blade wind turbine impeller comprises a rim 1 and multiple blades mounted via a blade support 2. The rim 1 is connected to disc-shaped flanges 7 mounted on either side of the impeller hub via slings 18 and stay cables 6. As shown in Figures 2 and 3, the rim 1 is assembled from an inner panel 11, a core panel 12, and an outer panel 13. The inner and outer panels 11 and 13 are sealed together at their edges to form a sandwich structure. A sealed cavity is defined between the inner and outer panels 11 and 13, with the core panel 12 positioned within the sealed cavity. Bent tips can be provided at the connecting portion of the inner and outer panels 11 and 13, creating tapered corners 15 on both sides of the rim, giving the rim a fusiform cross-section. The bend angle varies depending on the core panel layer and thickness. This design enhances rim strength while reducing the rim's windshield area. For example, a 1:1.5 taper can be formed when the inner and outer panels are bent and intersected. The rim can be designed according to the bearing capacity of the impeller rim, and the core plate can be selected with different levels of resistance and different shapes; the number and area of ​​the blades can be increased or decreased according to the size of the wheel diameter.

[0024] As shown in Figures 2 and 3, the impeller rim adopts inner and outer double-layer full-tip blades, including inner blades 4 and outer blades 3. The inner blades 4 are evenly distributed along the outside of the rim inner panel 11 through the blade bracket 2, and the outer blades 3 are evenly distributed along the outside of the rim outer panel 13 through the blade bracket, so that the inner blades and the outer blades are arranged in pairs. The blade bracket 2 mainly adopts a bottom beam set at the bottom of the blade, and can also be connected with semi-enclosed side brackets on both sides to facilitate connection and fixation and increase stability.

[0025] As shown in Figure 3, multiple dual-shaft variable pitch motors 8 are evenly distributed along the circumference of the center portion of the sealed cavity of the wheel rim. The ends of the two drive shafts 81 of the dual-shaft variable pitch motors pass through the through holes of the inner panel 11 and the outer panel 13, respectively, and connect to the center portion of the bottom crossbeam of the blade bracket 2. The dual-shaft variable pitch motors 8 drive the inner blades 4 and the outer blades 3 synchronously, forming a linked variable pitch. Limiting sliders 9 are connected to both sides of the bottom crossbeam of the blade bracket 2. An arcuate guide rail 10 is provided on the wheel rim panel at the same level as the limiting slider 9. The shape of the arcuate guide rail is the same as the arcuate trajectory of the limiting slider driven by the blade bracket. The sliding end of the limiting slider 9 is set within the arcuate guide rail 10. The inner panel 11 and the outer panel 13 are hinged to the edges of the blade bracket 2 on both sides through the electric push rod 5. An electric push rod can be hinged on each side of the blade bracket, and the tail of the electric push rod is set on one side of the corresponding rotation direction of the inner panel and the outer panel. The electric push rod auxiliary support promotes the rotation of the blade. The electric push rod plays the dual role of assisting pitch control and supporting the blade, while preventing the blade from falling off and ensuring safety. Specifically, the ball head at the front end of the electric push rod 5 can be installed in the ball seat 17 on the edge of the blade bracket 2 on both sides. The earring with a joint bearing at the tail of the electric push rod is connected to the earring base 16 on the same level of the rim panel through a pin shaft, which makes it easy to flexibly control the electric push rod to push the blade to rotate. Multiple reinforcement plates 14 are set in the rim sealing cavity. The reinforcement plates 14 are connected to the disc flanges 7 installed on both sides of the impeller hub through slings 18 and inclined cables 6. Specifically, multiple reinforcement plates 14 can be fixedly installed between the rim panel and the core panel 12. The reinforcement plates are used to connect the slings and increase the tensile strength of the rim. The reinforcement plates 14 are connected to one end of the sling 18, and the other end of the sling passes through the inner panel of the rim and plugs into one end of the diagonal cable. In this embodiment, at least three slings are used to pass through the inner panel and plug into one end of the diagonal cable. Two disc-shaped flanges 7 are fixedly connected through the hub 20 and the reinforcement ring 19. The other ends of the diagonal cables are connected to the two disc-shaped flanges 7 mounted on the hub 20, and radially cross-pushing to form the sandwich-rim double-blade wind turbine impeller. The structure using slings and diagonal cables is simple in structure and highly reliable. The diagonal cables also replace the transition support function of the root and middle of the traditional impeller blades, increasing the mechanical strength of the impeller body. The rim formed by the sandwich panel between the two panels has the advantages of large blade installation space, high structural strength, light weight, and a small windshield area.

[0026] As shown in Figures 4 to 9, as a further improvement, a guide rail mounting plate 21 can be provided on the outside of the inner panel 11 and the outer panel 13. The outer surface of the guide rail mounting plate is a flat surface, which is used to install the arc guide rail 10 so that the bottom of the arc guide rail is at the same height, which can compensate for the circular arc surface formed on the rim surface causing the bottom of the arc guide rail to form a curved surface, and the limit slider can slide on the arc guide rail.

[0027] The working process and principle of the present invention are as follows: the sandwich-rim double-blade wind turbine impeller is a rim made of a sandwich panel between inner and outer panels. Multiple sets of blades can be installed on both the inner and outer panels of the rim through blade brackets. The design concept of the present invention is based on the principle of leverage, especially the impeller system can rotate around the coaxial line, which is equivalent to using the axis as the fulcrum, the rim radius as a force-saving lever, and multiple small blades evenly distributed inside and outside the rim as the power. The sandwich-rim double-blade wind turbine impeller significantly increases the overall area of ​​the blade tip and uses the principle of leverage to increase the impeller torque. The edges of both ends of the rim panel are provided with angled corners. The angle of the angle varies according to the thickness of the core panel layer, and is based on the taper formed by the intersection of the angles of the two panels. This design scheme enhances the strength of the rim and reduces the windshield area of ​​the rim. A sealed cavity is defined between the inner and outer panels of the rim. A dual-shaft pitch motor is located in the center of this sealed cavity. The drive shafts of the dual-shaft pitch motor pass through the inner and outer panels and connect to the blade brackets that drive the blade pitch, achieving synchronized pitch control for both blades. Multiple reinforcement plates are fixed between the inner and outer panels and the core plate to connect to the sling cables, increasing the rim's tensile strength. The sling cables pass through the inner panels and connect to one end of the diagonal cable. The other ends of the diagonal cables connect to two disc-shaped flanges mounted on the hub, radially pulling each other together to form the sandwich-style, double-bladed wind turbine impeller. This structure is simple and highly reliable. The diagonal cables also replace the transitional support at the blade root and mid-blade, increasing the mechanical strength of the impeller. The rim, formed by the inner and outer panels and the core plate, offers high structural strength, light weight, and a small windshield area. The rim can be manufactured in sections and assembled on-site using connectors, simplifying transportation, lifting, and manufacturing. The double-layer blades, mounted on the inner and outer panels of the rim via blade brackets, are positioned essentially identically to the blade tips of existing three-blade impellers. This eliminates the aerodynamically inefficient root and the less aerodynamically efficient middle of the blade, emphasizing the use of the entire blade tip. This leverages the principle of leverage and significantly improves impeller torque. The double-layer blade design increases blade installation space, reduces starting wind speeds, and improves wind turbine efficiency. The blades are compact and lightweight, making them easier to manufacture, transport, and hoist, significantly reducing manufacturing costs. Multiple reinforcement plates are fixed between the inner and outer panels of the rim and the core plate. Each reinforcement plate is connected to a sling, and each group of at least three slings intersects and is plugged into one end of the inclined cable. The other end of the inclined cable is radially cross-connected to two disc-shaped flanges installed on the hub. The slings connected by multiple reinforcement plates increase the rim load capacity. The disc-shaped ports of the two disc-shaped flanges face outwards. The purpose of using butterfly flanges is: 1. to bypass the protruding position at the front end of the nacelle, and 2. to increase the inclined angle of the inclined cable to further enhance the strength of the wheel body.An electric push rod is arranged between the blade and the rim panel at the same level, and the ball head end of the electric push rod is installed in the ball seat on the blade. The tail of the electric push rod has an earring with a joint bearing and the earring base on the rim panel at the same level is connected through a pin shaft. The electric push rod plays a dual role of assisting pitch change and blade support, while preventing the blade from falling off and ensuring safety. The bottom of the blade bracket is provided with a downward-set limit slider, and the other end of the limit slider is embedded in an arc-shaped guide rail installed on the surface of the rim panel at the same level. The curvature of the guide rail is the same as the lateral rotation curvature of the blade bracket, so multiple connection points are added between the blade and the rim panel, and the edges at both ends of the rim panel are provided with angles. The angles and angles are different according to the thickness of the core board layer, and the taper is formed by the intersection of the angles of the two panels. This design enhances the strength of the rim and reduces the windshield area of ​​the rim. Suitable for use in high wind speed areas at sea and on land, this safe and reliable device features a rational design with fully synchronized double-blade pitch control. Its simple structure makes installation and adjustment easy, ensuring safe and reliable operation and extending the lifespan of the entire unit. Its lightweight design fundamentally addresses the issues of existing wind turbine impellers, such as the lack of blade tips, which fail to fully utilize the lever principle, resulting in low impeller torque. Furthermore, the connection between the blade root and the hub is weak, addressing the difficulties of manufacturing, transporting, and hoisting large blades, as well as low impeller efficiency. According to theoretical calculations, the torque generated by the blade tip per unit area is much greater than that generated by the blade mid-section and root. Therefore, a single impeller can drive two generators, significantly increasing torque despite the same impeller diameter.

[0028] As shown in Figures 4 to 9, when the sandwich-type rim double-blade wind turbine impeller of the present invention is in operation, the drive shaft of the dual-shaft variable-pitch motor is controlled to rotate, causing the windward surfaces of the inner blades 4 and outer blades 3 to rotate from the tangential direction of the rim circumference to the axial direction of the rim, with a rotation angle range of 0 to 60 degrees. At the same time, the electric push rod 5 can be controlled to retract and pull the inner and outer blades to rotate synchronously, assisting in supporting the inner and outer blades. The limit slider slides along the arc guide rail to assist in limiting the position and maintain the stability of the inner and outer blades. If the windward surfaces of the inner and outer blades are adjusted to return to their initial positions, the shaft of the dual-shaft variable-pitch motor can be controlled to rotate in the opposite direction, and the electric push rod can be controlled to stretch and push the inner and outer blades to rotate synchronously. The manufacturing process of the rim can adopt a segmented manufacturing method of outer panels, inner panels, and intermediate sandwich panels, and the rim is assembled on site using connectors to form the entire rim.

[0029] In summary, the purpose of the present invention is achieved.

Claims

1. A sandwich-type rim double-blade wind turbine impeller, comprising: The invention comprises a wheel rim and a plurality of blades arranged on the circumference of the wheel rim through a blade bracket, characterized in that: the wheel rim comprises a sandwich wheel rim with edges sealed and connected by an inner panel, a middle core panel and an outer panel, and the edges on both sides of the wheel rim are formed with conical angles, the blades comprise inner blades and outer blades, the inner blades are arranged on the outside of the inner panel of the wheel rim through a blade bracket, and the outer blades are arranged on the outside of the outer panel of the wheel rim through a blade bracket, and a plurality of double-output shaft pitch motors are evenly arranged along the circumference at the middle position of the sealed cavity between the inner panel and the outer panel, and the transmission shafts at both ends of the double-output shaft pitch motor can pass through the through holes of the inner panel and the outer panel respectively, and connect to the central part of the cross beam at the bottom of the blade bracket, so as to drive the inner blades and the outer blades to change pitch in linkage; the limit sliders connected on both sides of the bottom of the blade bracket are arranged in the arc guide rails of the wheel rim panel at the same level, and the inner panel and the outer panel are hinged to the edges on both sides of the blade bracket through an electric push rod that auxiliary supports and drives the blades to rotate; the wheel rim is connected to the disc flanges installed on both sides of the impeller hub through a sling and a diagonal cable by using an internal reinforcement plate.

2. The sandwich-type rim double-blade wind turbine impeller according to claim 1, characterized in that: The reinforcing plates are multiple reinforcing plates fixedly installed between the rim panel and the core plate. The reinforcing plates are connected to one end of the sling, and the other end of the sling passes through the inner panel of the rim and is plugged into one end of the inclined cable. The other end of the inclined cable is cross-connected to the two disc-shaped flanges.

3. The sandwich-type rim double-blade wind turbine impeller according to claim 1, characterized in that: The ball head at the front end of the electric push rod is installed in the ball seats at the edges of both sides of the blade bracket, and the earrings with joint bearings at the tail of the electric push rod are connected to the earring bases on the rim panel at the same level through pins.

4. The sandwich-type rim double-blade wind turbine impeller according to claim 1, characterized in that: The inner panel and the outer panel are provided with guide rail mounting plates whose outer surfaces are flat surfaces for mounting the arc-shaped guide rails.

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