Impeller for a wind turbine

Abstract

A hub (1) for a wind turbine comprises a rear ring (2) having a central axis (X). The hub (1) comprises a front ring (3) having an inner peripheral surface (4). The front ring (3) is arranged coaxially to the rear ring (2) and is associated in a slidable manner with the rear ring (2). The front ring (3) is movable along the central axis (X) and is switchable between a tight configuration and a spaced configuration with respect to the rear ring (2). The hub (1) comprises a plurality of blades (5) connected to the front ring (3) and defining a variable-pitch propeller (6). The blades (5) are adjustable between a minimum pitch when the front ring (3) is in the tight configuration and a maximum pitch when the front ring (3) is in the spaced configuration.

Description

Technical Field

[0001] This invention relates to an impeller for a wind turbine. This invention can also be used in generators for wind power generation. Background Technology

[0002] Equipment known in the prior art for wind energy production includes horizontal-axis wind turbines. These devices include a rotor comprising, for example, three blades. The rotor is connected to a nacelle positioned at the top of a tower. The nacelle is capable of rotating relative to the tower to align itself with the direction of the wind. The rotor shaft is located within the nacelle and is arranged to transmit the rotational motion of the blades to a gearbox. The gearbox transmits the motion to another shaft, known as a high-speed shaft, which drives a generator.

[0003] US1555349A describes a fan constructed for operating a pump. The fan includes a pair of coaxial rings spaced apart from each other and blades radially arranged between the rings, having an arcuate shape. Furthermore, the fan includes a spring connecting the rings, and the spring is configured to contract to bring the rings closer together. Additionally, during spring contraction, the blades reorient, thereby increasing the exposed surface area.

[0004] The downside is that energy production under current technology depends on two factors: wind speed and the actual area of ​​the disk formed by the blades during rotation. To optimize equipment performance, a considerable wind speed is required, which is not present at ground level; therefore, the blades must be mounted at a fairly high altitude. Furthermore, large blades must be used to maximize the actual disk area. Due to these operating conditions, the transportation and installation of the equipment are complex. Summary of the Invention

[0005] In this context, the technical objective of the present invention is to provide an impeller for a wind turbine that overcomes the disadvantages of the prior art.

[0006] In particular, the object of the present invention is to provide an impeller for a wind turbine that maximizes the power generated even when the wind speed is not optimal.

[0007] Another object of the present invention is to provide an impeller for a wind turbine that requires fewer blades to produce the same power.

[0008] The technical tasks and objectives are essentially achieved by the impellers for wind turbines, which include the technical specifications described in one or more of the following technical solutions.

[0009] In particular, the impeller for a wind turbine according to the invention includes a rear ring having a central axis.

[0010] The front ring has an inner circumferential surface and is arranged coaxially relative to the rear ring, and is slidably associated with the rear ring. The front ring can move along the central axis; its configuration relative to the rear ring varies between a compact configuration and a separated configuration.

[0011] Multiple blades are connected to the front ring and define the variable-pitch propeller. The blades can be adjusted between the minimum pitch when the current ring is in a tight configuration and the maximum pitch when the current ring is in a split configuration.

[0012] The shaft extends along a central axis. The shaft includes a rear portion connected to a rear ring and a front portion connected to a front ring. The front portion of the shaft is configured to undergo a translational motion relative to the rear portion to switch the front ring between a tight configuration and a spaced configuration, and has a front cavity extending along the central axis. The rear portion of the shaft is at least partially inserted into the front cavity.

[0013] The front portion includes at least one helical guide disposed on an inner surface. The rear portion includes at least one slider associated with the helical guide and disposed on an outer surface.

[0014] This type of impeller for wind turbines solves the technical problem because its design can be optimized for wind speed. In fact, the front ring, which translates along the central axis, alters the blade spacing. This adjusts the angle of airflow incidence, allowing for maximum energy output even at lower wind speeds. Advantageously, the impeller does not require large blades: due to the optimized airflow, it can have a smaller size while producing the same power. Attached Figure Description

[0015] Other features and advantages of the invention will become more apparent from the description of exemplary, non-exclusive, and therefore non-limiting preferred embodiments for wind turbine impellers, as illustrated in the accompanying drawings, in which:

[0016] - Figure 1 This is an exploded perspective view of the impeller according to the present invention;

[0017] - Figure 2 yes Figure 1 Another exploded view of the impeller from different angles;

[0018] - Figure 3 yes Figure 1 and Figure 2 A three-dimensional rear view of the impeller;

[0019] - Figure 4 yes Figure 1 and Figure 2 A cross-sectional side view of the impeller;

[0020] - Figure 5 yes Figure 1 and Figure 2 A three-dimensional front view of the first detailed part of the impeller;

[0021] - Figure 6 yes Figure 5 A three-dimensional rear view of the detailed parts;

[0022] - Figure 7 yes Figure 1 and Figure 2 A three-dimensional view of the second detailed part of the impeller;

[0023] - Figure 8 yes Figure 1 and Figure 2 A magnified front view of the third detail of the impeller;

[0024] - Figure 9 This is a schematic side view of a turbine according to the present invention. Detailed Implementation

[0025] Referring to the accompanying drawings, 1 refers to the impeller for a wind turbine according to the present invention.

[0026] like Figure 3 As shown, the impeller 1 includes a front ring 3 through which airflow enters and a rear ring 2 through which airflow flows outward. The impeller 1 also has a central axis X.

[0027] like Figure 5 As shown, the front ring 3 has a converging portion 30, which has a frustoconical shape for directing airflow toward the interior of the impeller 1. Specifically, the converging portion 30 has an inlet section 31 defined at the leading edge of the front ring 3. The converging portion 30 has an intermediate section 33 located inside the front ring 3 and having a smaller area relative to the inlet section 31. A cylindrical portion 38 is connected to the converging portion 30. The cylindrical portion 38 has the same diameter as the smaller section 33 of the converging portion 30 and extends along the central axis X.

[0028] like Figure 1 As shown, the front ring 3 includes a front portion 39 and a rear wall 50. The front portion 39 has a cylindrical shape and has a diameter substantially the same as the larger section 31 of the converging portion 30. The rear wall 50 includes an inner circumferential surface 4 and an outer circumferential surface 35. The outer circumferential surface 35 has a cylindrical shape and has a diameter substantially the same as the cylindrical portion 38. The inner circumferential surface 4 is opposite to the outer circumferential surface 35. Furthermore, the inner circumferential surface 4 includes a plurality of flat surfaces 25, alternating with intermediate surfaces 34 that may have different geometries, such as portions of cylindrical side surfaces. Figure 6 As shown, the rear wall 50 typically has a dimension L in the direction of the central axis X, which is larger than the dimension D of the front part 39 in the direction of the central axis X.

[0029] It should be noted that, such as Figure 4 As shown, the impeller 1 includes a shaft 7 extending along the central axis X. The shaft 7 includes a rear portion 8 connected to the rear ring 2 and a front portion 9 connected to the front ring 3. Further details of the shaft 7 will be provided later in this specification.

[0030] like Figure 5 As shown, the front ring 3 includes a plurality of front radial elements 21. Each front radial element 21 includes a first end 40 fixed to the front portion 9 of the shaft 7 and a second end 41 connected to a cylindrical portion 38 of the inner circumferential surface 4. Furthermore, as... Figure 6 As shown, each radial element 21 includes a rear edge 42, which is considered to be the edge facing the rear ring 2.

[0031] Now for reference Figure 7 The rear ring 2 shown has a cylindrical shape and includes an inner surface 45. Furthermore, the rear ring 2 extends along a central axis X passing through its center. The front ring 3 is arranged coaxially relative to the rear ring 2. The diameter of the rear ring 2 is larger than the diameter of the rear wall 50 of the front ring 3 and smaller than the diameter of the front portion 39 of the front ring 3.

[0032] The rear ring 2 includes a plurality of rear radial elements 23. Each rear radial element 23 includes a first end 43 fixed to the rear portion 8 of the shaft 7 and a second end 44 connected to the inner surface 45 of the rear ring 2. Furthermore, each radial element 23 includes a groove 24, as shown in detail... Figure 8 The distance between two consecutive radial elements is greater than the width of slot 24.

[0033] like Figure 1 As shown, the impeller 1 includes a plurality of blades 5, preferably eight, connected to the front ring 3. The number of front radial elements 21 and rear radial elements 23 corresponds to the number of blades 5. The blades 5 define a variable-pitch propeller 6. Figure 1 As shown, each blade 5 has an outer edge 26, an inner edge 20, and a leading edge 22. The outer edge 26 contacts a corresponding flat surface 25 of the inner circumferential surface 4. The inner edge 20 contacts the impeller shaft 7. The leading edge 22 is considered to be the edge of each blade 5 closest to the inlet of the incident airflow. The leading edge 22 of each blade 5 is hinged to a corresponding trailing edge 42 of the front radial element 21.

[0034] More specifically, each blade has a body 47 and a tail 46. The tail 46 forms an angle with the body 47. Each tail 46 is inserted into a corresponding slot 24 of the rear radial element 23. Furthermore, as... Figure 1 As shown, the tail 46 has an intermediate edge 37 that is considered to be between the tail 46 and the body 47 of the blade 5 and a rear edge 32 opposite to the front edge 22.

[0035] It should be noted that the front part 9 and the rear part 8 of shaft 7 have a front cavity 10 and a rear cavity 15, respectively, as shown in the figure. Figure 1and Figure 7 As shown. The front cavity 10 and the rear cavity 15 extend along the central axis X. The rear portion 8 of the shaft 7 is at least partially inserted into the front cavity 10.

[0036] It should be noted that, such as Figure 6 As shown, the front portion 9 of the shaft 7 has an inner surface 12, on which at least one helical guide portion 11 is included. Figure 7 As shown, the rear portion 8 includes an outer surface 14 on which at least one slider 13 is provided, the slider being associated with the helical guide portion 11 of the front portion 9. Figure 5 As shown, the front portion 9 has an outer surface 18 on which a plurality of flat surfaces 19 are provided. The flat surfaces 19 of the front portion 9 alternate with side surfaces 36, which may have different geometries, such as portions of the cylinder side surface. Furthermore, each flat surface 19 of the front portion 9 contacts a corresponding inner edge 20 of the blade 5, such as... Figure 1 As shown.

[0037] It should be noted that the front ring 3 is slidably associated with the rear ring 2 and switches between a compact configuration and a spaced configuration relative to the rear ring 2 along the central axis X. Indicatively, the maximum travel of the front ring 3 relative to the rear ring 2 is on the order of 10 cm along the central axis X. When the configuration of the front ring 3 is changed in a reversible manner, the rear ring 2 is inserted between the rear wall 50 and the front portion 39. Furthermore, by changing the configuration of the front ring 3, the orientation of the blade 5 can be adjusted between the minimum spacing when the current ring 3 is in a compact configuration and the maximum spacing when the current ring 3 is in a spaced configuration.

[0038] When the current ring 3 changes its configuration, the blades 5 are adjusted. The hinge between each leading edge 22 of the blade 5 and the corresponding trailing edge 42 of the leading radial element 21 allows the body 47 of the blade 5 to tilt, thereby changing the propeller 6 pitch and optimizing the airflow. When the blades 5 are adjusted, the outer edge 26 and the inner edge 20 slide on the corresponding flat surfaces 25 of the inner circumferential surface 4 and 19 of the front portion 9, respectively. The edges 26 and 20 slide in the same direction and maintain contact with the corresponding flat surfaces 25 and 19. In addition, each tail portion 46 of the blade 5 can slide into a corresponding groove 24 located in the portion between the middle edge 37 and the trailing edge 32.

[0039] It should be noted that the front portion 9 of the shaft 7 is configured to translate rotatably relative to the rear portion 8, thereby reversibly switching the front ring 3 between the compact and split configurations. Advantageously, controlled translation of the rear portion 8, and thus the front ring 3, is achieved by associating the slider 13 of the rear portion 8 with the corresponding helical guide 11 of the front portion 9. Furthermore, during the switching of the front ring 3 between the compact and split configurations, each inner edge 20 can slide along the flat surface 19 of the front portion 9.

[0040] It should be noted that, such as Figure 1 and Figure 4 As shown, the impeller 1 includes an actuator 16 inserted into the front chamber 10 and the rear chamber 15. The actuator 16 includes a fixed end 17 inserted into the rear chamber 15 of the rear portion 8 and a movable end 18 inserted into the front chamber 10 of the front portion 9. In use, the actuator 16 is switched and operated between a contracted configuration (for switching the front ring 3 to a tight configuration) and an extended configuration (for switching the front ring 3 to a split configuration).

[0041] It should be noted that, such as Figure 9 As shown, the impeller 1 can be connected to a wind turbine 27, which includes a frame 28, a transmission 29, and an alternator 49. Specifically, the transmission 29 may include a rotor shaft 48. The rear ring 2 is fixed along the central axis X and connected to the transmission 29.

Claims

1. An impeller (1) for a wind turbine, comprising: - Rear ring (2), with a central axis (X); - A front ring (3) having an inner circumferential surface (4); the front ring (3) is arranged coaxially with respect to the rear ring (2); the front ring (3) is slidably associated with the rear ring (2) and is movable relative to the rear ring (2) along the central axis (X) between a compact configuration and a separated configuration; - Multiple blades (5) are connected to the front ring (3) and define a variable-pitch propeller (6), the blades (5) being adjustable between a minimum pitch when the front ring (3) is in the tight configuration and a maximum pitch when the front ring (3) is in the split configuration; - A shaft (7) extending along the central axis (X); the shaft (7) includes a rear portion (8) connected to the rear ring (2) and a front portion (9) connected to the front ring (3); the front portion (9) of the shaft (7) is configured to undergo a translational motion relative to the rear portion (8) to allow the front ring (3) to switch between the tight configuration and the separated configuration; the front portion (9) of the shaft (7) has a front cavity (10) extending along the central axis (X); the rear portion (8) of the shaft (7) is at least partially inserted into the front cavity (10). The front portion (9) has an inner surface (12), the rear portion (8) includes an outer surface (14), the front portion (9) includes at least one helical guide portion (11) disposed on the inner surface (12); the rear portion (8) includes at least one slider (13) associated with the helical guide portion (11) and disposed on the outer surface (14).

2. The impeller according to claim 1, characterized in that, The rear portion (8) of the shaft (7) has a rear cavity (15) extending along the central axis (X); the impeller (1) includes an actuator (16) inserted into the front cavity (10) and the rear cavity (15); the actuator (16) includes a fixed end (17) connected to the rear ring (2) and a movable end (18) connected to the front ring (3); the actuator (16) can be operated to reversibly switch the rings (2, 3) between the compact configuration and the separated configuration.

3. The impeller according to claim 1, characterized in that, The front portion (9) has an outer surface (18); the outer surface (18) of the front portion (9) has a plurality of flat surfaces (19); each blade (5) has an inner edge (20) that contacts the corresponding flat surface (19) of the front portion (9).

4. The impeller according to claim 1, characterized in that, The front ring (3) includes a plurality of front radial elements (21) connected to the front portion (9); each blade (5) has a front edge (22) hinged to the corresponding front radial element (21).

5. The impeller according to claim 1, characterized in that, The rear ring (2) includes a plurality of rear radial elements (23); each rear radial element (23) has a corresponding groove (24); each blade (5) is slidably inserted into the corresponding groove (24).

6. The impeller according to claim 1, characterized in that, The inner circumferential surface (4) of the front ring (3) has a plurality of flat surfaces (25); each blade (5) has an outer edge (26) that contacts a corresponding flat surface (25) of the inner circumferential surface (4).

7. A wind turbine (27) comprising a frame (28), a transmission (29) and an impeller (1) according to claim 1; the rear ring (2) of the impeller (1) is connected to the transmission (29) and fixed along the central axis (X).

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