Impeller for wind power generation and wind power generation system

Abstract

An object of the present invention is to provide an impeller and a wind power generation system, which can set a plurality of wind power generation devices in a limited area, efficiently generate electricity from the entire area, and can suppress the noise generated by the rotation of the impeller during wind power generation to a small level. The present invention relates to an impeller for wind power generation, which includes: a plurality of blades; and a hub provided with a rotating shaft at the center, and the plurality of blades are arranged at substantially equal intervals in the circumferential direction. The blades are formed to extend while expanding the width toward the outer periphery of the impeller, and a line segment connecting the leading edge and the trailing edge of the blade is inclined at an angle of substantially 10 degrees or more and substantially 20 degrees or less with respect to a plane perpendicular to the rotating shaft of the impeller. When viewed from the front of the impeller, a part of the trailing edge of the blade in front of the rotating direction of the impeller and the leading edge of the blade behind the rotating direction overlap.

Description

Technical Field

[0001] The present invention relates to an impeller for wind power generation that can improve power generation efficiency and has excellent quietness, and a wind power generation system including the impeller for wind power generation. Background Art

[0002] In recent years, due to considerations for the global environment, there has been an increasing focus on power generation devices that utilize clean energy. As one such power generation device, a wind power generation device can be cited. A wind power generation device is a device that rotates an impeller by wind and converts the rotational energy obtained from the rotation of the impeller into electric energy.

[0003] In addition, due to reasons such as an increase in power demand, it is desired to increase the power generation amount of wind power generation devices. For example, in Patent Document 1, a wind power generation device is proposed that has a wind tunnel for collecting wind provided on an impeller in order to increase the power generation amount.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Laid-Open No. 11-182405 Summary of the Invention

[0007] Technical Problem to be Solved by the Invention

[0008] Generally, there is a tendency that the larger the area of the blades of an impeller that withstands wind, or the faster the rotational speed of the impeller, the greater the power generation amount of the wind power generation device. In addition, it is known that when impellers having the same diameter and different numbers of blades are compared with each other, the fewer the number of blades, the faster the rotational speed of the impeller. Therefore, most of the currently mainstream wind power generation devices having an impeller with three blades are designed to have a longer blade diameter in order to increase the blade area. However, if multiple wind power generation devices are to be installed in a limited area, the longer the blade diameter, the fewer the number of wind power generation devices that can be installed, and as a result, the power generation amount obtained from the entire area becomes smaller. In addition, the problem of noise generated by the friction between the blades and the air is also one of the reasons why the installation locations of wind power generation devices are restricted. For these reasons, there is a need for an impeller and a wind power generation system that can install multiple wind power generation devices in a limited area, efficiently generate power from the entire area, and have excellent quietness.

[0009] The present invention has been made in view of the above problems. That is, an object of the present invention is to provide an impeller and a wind power generation system that can efficiently generate power from the entire area even when installed in a limited narrow area. Another object of the present invention is to provide an impeller and a wind power generation system that can suppress the noise generated by the rotation of the impeller during wind power generation to a small level.

[0010] Solution for Solving Technical Problems

[0011] The present invention solves the above problems by any one of the following [1] to [4]. [1] An impeller for wind power generation, comprising: a plurality of blades; and a hub having a rotating shaft provided at the center and arranging the plurality of blades at substantially equal intervals in the circumferential direction. The blades are formed to extend while expanding the width toward the outer periphery of the impeller, and a line segment connecting the leading edge and the trailing edge of the blade is inclined at an angle of approximately 10 degrees or more and approximately 20 degrees or less with respect to a plane perpendicular to the rotating shaft of the impeller. When viewed from the front of the impeller, a part of the trailing edge of the blade in front of the rotating direction of the impeller and the leading edge of the blade behind the rotating direction of the impeller overlap;

[0012] [2] The impeller for wind power generation according to [1], wherein the plurality of blades are five in number, and when viewed from the front of the impeller, the blade in front of the rotating direction of the impeller and the blade behind the rotating direction of the impeller do not overlap at the outer peripheral portion of the impeller;

[0013] [3] The impeller for wind power generation according to [1] or [2], wherein the blade is formed of a plate-like material having substantially the same thickness, and the windward side surface is a flat surface;

[0014] [4] A wind power generation system, comprising a wind power generation device, the wind power generation device at least having: a wind tunnel formed with a longitudinal section cut along the central axis being substantially streamlined; an impeller according to any one of [1] to [3], which is disposed in the wind tunnel; and a generator that generates electricity by the rotation of the impeller.

[0015] Advantages of the Invention

[0016] According to the present invention, it is possible to provide an impeller and a wind power generation system that can efficiently generate electricity from the entire area even when installed in a limited narrow area. In addition, according to the present invention, it is possible to provide an impeller and a wind power generation system that can suppress the noise generated by the rotation of the impeller during wind power generation to a small level. Description of the Drawings

[0017] Figure 1 is an example of the front view of the impeller according to the embodiment of the present invention.

[0018] Figure 2 is an example of the side view of the impeller according to the embodiment of the present invention.

[0019] Figure 3 is an example of the front view and the outer peripheral side view of the blade according to the embodiment of the present invention.

[0020] Figure 4This is an example of a partial top view cross-sectional view of a wind power generation device according to an embodiment of the present invention.

[0021] Figure 5 This is a partial cross-sectional view showing an example of the structure of a wind power generation system according to an embodiment of the present invention. Detailed Embodiment

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the drawings and embodiments. In addition, the present invention is not limited to the preferred numerical values or structures described below.

[0023] Figure 1 This is an example of a front view of an impeller according to an embodiment of the present invention. In addition, Figure 2 This is an example of a side view of an impeller according to an embodiment of the present invention. Figure 1 And Figure 2 The impeller 11 shown at least includes a hub 12 and a plurality of blades 13.

[0024] As Figure 1 shown, the impeller 11 is formed such that each of the blades 13a to 13e extends from the side surface of the hub 12 toward the outer peripheral direction of the impeller 11 while expanding the width of the blade. In addition, the blades 13a to 13e are arranged at substantially equal intervals in the circumferential direction of the hub 12 so as to surround the hub 12. In addition, the hub 12 is configured such that its center is the rotation center P of the impeller 11 0 , and at the rotation center P 0 a rotating shaft for transmitting the rotational force of the impeller 11 to the generator can be connected.

[0025] Figure 2 This is an example of a side view of an impeller according to an embodiment of the present invention. As Figure 1 And Figure 2 shown, when viewed from the rotation direction of the blade 13, the blade 13 is inclinedly mounted on the hub 12 such that the trailing edge (rear edge) at the rear is located on the downwind side of the leading edge (front edge) at the front. In addition, the width of the blade 13 is formed in a substantially fan shape in which the width of the end edge in the outer peripheral direction of the impeller 11 is wider than the width near the portion where the blade 13 is connected to the hub 12.

[0026] There is no particular limitation on the number of blades 13 of the impeller 11. For example, it is preferably 3 to 5. If the number of blades 13 is less than 3, the amount of wind borne by the blades 13 as a whole becomes smaller, and the power generation efficiency decreases. In addition, since the number of blades for transmitting the energy of the wind to the hub is too small, the torque required to drive the generator cannot be obtained sufficiently, and the power generation efficiency decreases. On the other hand, if the number of blades 13 is 6 or more, the vortices of the wind generated by the friction between the blades 13 and the air increase, and the noise increases. In addition, compared with the case of 3 to 5 blades, although a larger torque can be obtained, the rotational speed of the impeller tends to decrease rapidly. Therefore, the efficiency of converting the wind power into the rotational force of the impeller 11 also deteriorates, and the power generation efficiency decreases. In addition, since the mass of the entire impeller also becomes heavier, the structural load on the hub 12 and the rotating shaft 2 also becomes larger, which has an adverse effect on the durability of the impeller 11.

[0027] As the number of blades 13, 5 is particularly preferred. When the number of blades 13 is 5, a larger torque sufficient to drive the generator can be obtained compared with the case of 4 blades. In addition, although the wind-receiving area of each blade becomes smaller, the wind-receiving area of the entire impeller can be increased. Therefore, the wind power can be converted into rotational force with high efficiency. In a structure where the number of blades is 4 or less, when it is necessary to ensure the same wind-receiving area as in the case of 5 blades, it is necessary to design to increase the blade width to increase the mass of the blade or increase the diameter of the blade. If the blade width is increased to increase the mass of the blade, the structural load on the hub 12 also becomes larger, which has an adverse effect on the durability of the impeller 11. If it is designed to increase the diameter of the blade, the number of installed wind power generation devices decreases, and as a result, the power generation amount obtained from the entire area decreases.

[0028] When the number of blades 13 is 5, a relatively high power generation efficiency can also be obtained compared with the case where the number of blades is 6 or more. When the number of blades is 5, the wind-receiving area of each blade can be increased compared with the case where the number of blades is 6 or more. In addition, conversely, when ensuring a space between the blades to allow the wind to pass from the front to the rear of the impeller, a sufficient space can also be ensured compared with the case of 6 or more blades. When the space between two adjacent blades is narrow, the impeller itself may block the air flow, or the vortices of the wind generated by the friction between the impeller and the air may stay in place for a long time, so the flow of the wind flowing in from the front of the impeller may stall, and the rotational efficiency of the impeller decreases. As a result, the power generation efficiency decreases.

[0029] By adopting the structure with 5 blades 13 of the impeller 11, while obtaining sufficient torque required for power generation, the flow of the wind passing through the blades will not stall, and power generation can be carried out while maintaining a relatively high rotational efficiency. In addition, since it does not obstruct the flow of air, the generation of wind vortices can also be suppressed, so the noise can be suppressed to a relatively low level. In addition, since the number of blades is limited to 5, the load exerted on the rotating shaft 2 by the overall mass of the impeller 11 can be reduced, and the impeller 11 has the advantage of being not easily damaged. Furthermore, compared with the case where the number of blades 13 is 6 or more, the manufacturing cost can be suppressed.

[0030] Next, use Figure 1 and Figure 2 to explain the inclination angles of the respective blades 13. As Figure 2 shown, when viewed from the rotation direction of the blade 13a, each blade 13 including the blade 13a in the present embodiment is inclinedly mounted on the hub 12 in such a manner that the rear edge (trailing edge 15b) is located on the leeward side of the front edge (leading edge 15a). Here, on the plane perpendicular to the rotating shaft 2a, the radius from the rotation center P 0 of the impeller 11 to the outer peripheral edge located at the outermost periphery of the impeller 11 is defined as R, and the intersections of the circumference of the circle with a radius of 1 / 4R with the leading edge 15a and the trailing edge 15b of the blade 13a are respectively set as P 2 , P 3 . In addition, if the inclination angle of the line segment P 2 connecting P 3 and P 2 P 3 with respect to the plane perpendicular to the rotating shaft 2a is defined as θ, the inclination angle θ is preferably 10 degrees or more, more preferably 12 degrees or more. In addition, the inclination angle θ is preferably 20 degrees or less, more preferably 18 degrees or less. When the inclination angle θ is in the range of 14.5 degrees or more and 15.5 degrees or less, when the blade is subjected to wind, the wind force can be converted into rotational force most efficiently. On the other hand, if the inclination angle θ is greater than 20 degrees, the vibration of the blade when subjected to wind becomes larger, the noise increases, and at the same time, turbulence is also generated. In addition, if the inclination angle θ is less than 10 degrees, the blade itself becomes a resistance that obstructs the flow of wind, the wind speed is greatly reduced, so the rotational speed of the blade drops sharply, and the power generation efficiency also decreases.

[0031] Each blade 13 including the blade 13a in the present embodiment is configured such that the inclination angle θ of the line segment P 2 P 3 is defined in such a manner that the rear edge (trailing edge 15b) is located on the leeward side of the front edge (leading edge 15a), but the line segment P 2 P 3 can also be positioned in such a way that the inclination angle θ is reversed by 180 degrees.. In this case, the rotation direction of the impeller is opposite to that of the impeller 11 in the present embodiment. In addition, the points P 2 , P 3 in the present embodiment are defined as the intersection points of the circumference of a circle with a radius of 1 / 4R centered on the rotation center P 0 and the leading edge 15a and the trailing edge 15b of the blade 13a. However, the points P 2 , P 3 can be any points as long as they are on the leading edge 15a and the trailing edge 15b of the blade 13a, respectively.

[0032] Next, Figure 1 and Figure 3 are used to describe the shape of each blade 13 of the impeller 11. Each blade 13 of the impeller 11 in the present embodiment ensures the area of the blade required to generate a specified power by adopting a structure in which the blade width gradually expands toward the outer periphery of the impeller 11. In Figure 1 , the width of each blade 13 is formed such that the width of the end edge in the outer peripheral direction of the impeller 11 is wider than the width near the portion where the blade 13 is connected to the hub 12, and has a substantially fan-shaped shape. In addition, the shape of the blade 13 is not particularly limited. However, as Figure 1 shows, when observing the blade 13a from the front, it is preferably formed such that the intersection point P 1 of the straight lines respectively extending the leading edge 15a and the trailing edge 15b of the blade 13a is located in a region on the opposite side of the rotation center P 0 from the outer peripheral edge 15d of the blade. By adopting such a structure, even near the portion where the blade 13a is connected to the hub 12, it is possible to ensure that the area of the blade 13 exposed to the wind is large. In addition, the area of the entire impeller 11 exposed to the wind can be increased, and the power generation efficiency can be further improved.

[0033] Figure 3 is an example of the front view and the outer peripheral side view of the blade according to the embodiment of the present invention. As Figure 3 shows, the blade 13a is preferably in the shape of a single plate formed by processing a thin plate-like member into a planar shape with substantially the same thickness. That is, when observing the blade 13a from the outer peripheral edge 15d side of the blade 13a, as shown in the outer peripheral side view 15e of the outer peripheral edge 15d, it is preferably formed such that the thickness is substantially the same throughout. In addition, the shape of the wind-receiving portion (the region surrounded by the leading edge 15a, the trailing edge 15b, and the outer peripheral edge 15d) of the blade 13a is preferably planar. The material of the blade 13a is not particularly limited as long as it is a thin plate-like member. However, considering ease of processing, light weight, strength, etc., FRP is preferred.

[0034] In this embodiment, the material of the blade 13a is a thin plate-like component. Therefore, the air resistance during rotation is small, and the wind is not likely to be disturbed when passing through the blade 13a. As a result, the rotation efficiency of the impeller 11 can be improved. In addition, since the shapes of the blades 13a to 13e are plate shapes with substantially the same overall thickness of the blades, compared with the blades having a streamline shape and curved outward in the peripheral direction as in the past, the processing during manufacturing is easy, and the manufacturing cost of each blade can be suppressed.

[0035] Next, Figure 1 Two adjacent blades 13a and 13b among the respective blades 13a to 13e of the impeller 11 will be described. The impeller 11 is preferably configured such that, when viewed from the front of the impeller 11, the blade 13a in front of the rotation direction of the impeller 11 and the blade 13b behind the rotation direction do not overlap in the outer peripheral portion of the impeller 11. That is, in the relationship between two adjacent blades, it is preferable to ensure a predetermined space between the trailing edge 15b of the blade 13a and the leading edge 15c of the blade 13b. When the impeller 11 rotates under the action of wind, between the respective blades 13, vortices of wind are generated due to the friction between the blades and the air. The vortices of wind generated by the blade 13a in front of the rotation direction will interfere with the rotational movement of the blade 13b that comes later, resulting in a decrease in the rotation efficiency of the impeller 11 itself. Therefore, by providing a predetermined space between the adjacent blades, it is easy for the vortices and turbulence of the wind generated between the blades to escape in the downwind direction, and the mutual interference between the adjacent blades in the rotation direction of the impeller can be suppressed. In addition, by mutually ensuring a predetermined space between the respective blades 13 of the impeller 11, it is possible to prevent the flow of the wind passing through the impeller 11 from being disturbed and the air from staying behind, and it is also possible to prevent the amount of air flowing into the impeller 11 from decreasing and the wind from stalling. Therefore, the rotation efficiency of the entire impeller 11 can be improved.

[0036] However, on the other hand, if only the space between the adjacent blades 13a and 13b is enlarged, the wind-receiving area of the entire impeller 11 becomes narrow, and the efficiency of converting the wind force into the rotational energy of the impeller decreases. Therefore, it is preferably configured such that, when viewed from the front of the impeller, a part of the trailing edge 15b of the adjacent blade 13a and the leading edge 15c of the blade 13b located behind the rotation direction overlap. By adopting such a structure, the wind-receiving area of the blades of the entire impeller 11 can be increased. Therefore, even if the diameter of the blade 13 is not increased, the wind force can be efficiently converted into the rotational energy of the impeller.

[0037] The overlapping region 14 between the trailing edge 15b of the blade 13a and the leading edge 15c of the blade 13b of the impeller 11 is preferably a portion close to the hub 12. The overlapping region 14 of the two blades is on a plane perpendicular to the rotation axis, and from the rotation center P of the impeller 11 0When the radius to the outer peripheral edge at the outermost periphery of the impeller 11 is defined as R, it is preferably included in the region surrounded by a circle with a radius of 1 / 2R, and more preferably included in the region surrounded by a circle with a radius of 1 / 3R. By adopting such a structure, the mutual interference between adjacent blades can be suppressed, the wind flowing into the impeller 11 can be prevented from stalling, and at the same time, the overall impeller 11 can increase the wind receiving area, so that the wind power can be efficiently converted into the rotational energy of the impeller. In addition, through such a structure, the generation of wind vortices can be suppressed and noise can be suppressed, and at the same time, effective power generation can be carried out.

[0038] Figure 4 is an example of a partial top view cross-sectional view of a wind power generation device using the impeller 11 according to an embodiment of the present invention. As Figure 4 shown, the wind power generation device 5 using the impeller 11 includes an impeller 11, a rotating shaft 2, a spur gear 3, a planetary gear 4, and a generator 8. The impeller 11 of the present invention is connected to one end of the rotating shaft 2 in such a way that its rotation center overlaps with the rotation center of the rotating shaft 2. Here, the rotating shaft 2 is connected to a spur gear 3 for transmitting the rotational force to the generator 8 on the other end side thereof. In addition, when the impeller 11 is subjected to wind, the rotating shaft 2 rotates together with the impeller 11, and the rotational energy is transmitted to the generator 8. In addition, in the generator 8, the rotational energy is converted into electric energy and collected to a power collection device through a power collection cable or the like connected to the generator 8.

[0039] The planetary gear 4 is provided on the rotating shaft 2 and functions to generate a sufficiently large torque required for power generation even at the high-speed rotation of a small-diameter impeller. Through such a structure, the wind power can be efficiently converted into the rotational energy of the impeller, and more efficient power generation can be carried out.

[0040] A torque limiter is connected to the generator 8 and has a function of decelerating the rotational speed when the load applied to the wind power generation device 5 reaches a specified value or more. That is, it has a function of preventing the over-rotation of the rotating shaft 2 and the impeller 11 connected thereto. When the wind is strong and the rotating shaft 2 exceeds the specified rotational speed, an excessive load is also applied to the generator 8 connected to the spur gear 3, and there is a tendency for the motor provided inside the generator 8 to be damaged more easily. However, by providing a torque limiter, the possibility of damage to the generator 8 can be reduced. In addition, by preventing over-rotation, the friction between the air and the blade 13 can be reduced, and noise can be suppressed. It should be noted that in the present embodiment, the impeller 11 of the present invention is used for the wind power generation device 5 provided with a torque limiter, but it can also be used for a power generation device not provided with a torque limiter.

[0041] The wind power generation device 5 using the impeller 11 according to the embodiment of the present invention is preferably provided in a specified wind tunnel.

[0042] Figure 5 This is an example of a partial cross-sectional view of a wind power generation device 5 using an impeller 11 according to an embodiment of the present invention. In this specification, "substantially streamlined" refers to a shape in which the shape of the inner peripheral edge portion in the longitudinal cross-section of the wall of the wind tunnel is deformed within a range that can achieve the purpose, and the purpose is to increase the speed of the wind flowing into the interior from the air intake side of the wind tunnel without generating turbulence inside the wind tunnel. In addition, "substantially streamlined" also includes a shape in which the shape of the outer peripheral edge portion in the longitudinal cross-section of the wall of the wind tunnel is deformed within a range that can achieve the purpose, and the purpose is to prevent the generation of vortices on the outer peripheral surface. As an example of such a deformation, there may be a case where the shape of the outer peripheral edge portion in the longitudinal cross-section of the wall of the wind tunnel is streamlined in a part from the front end portion to the rear end portion of the wind tunnel. In addition, "substantially streamlined" also includes a shape in which the shape of the outer peripheral edge portion in the longitudinal cross-section of the wall of the wind tunnel is formed into a straight line shape.

[0043] The wind tunnel 6 includes at least a front end portion 61 that forms an air intake, a minimum inner diameter portion 62 where the inner diameter of the wind tunnel 6 is the smallest, and a rear end portion 63 that forms an exhaust port. The inner diameter of the wind tunnel 6 is configured to gradually decrease from the front end portion 61 to the minimum inner diameter portion 62 and gradually increase from the minimum inner diameter portion 62 to the rear end portion 63. That is, a part of the inner wall of the wind tunnel 6 bulges toward the central axis 64 of the wind tunnel, and a minimum inner diameter portion 62 with the smallest inner diameter of the wind tunnel is formed between the air intake and the exhaust port. In this way, the wind tunnel 6 is configured to have a substantially streamlined longitudinal cross-section along the central axis 64, thereby enabling the wind flowing into the interior of the wind tunnel 6 from the air intake of the wind tunnel to be accelerated, and improving the power generation amount and power generation efficiency. In addition, by accelerating the wind inside the wind tunnel, it is not necessary for the blades of the impeller to obtain lift by themselves, so sufficient power generation performance can be obtained even if the blades are not in the streamline shape or the shape that bends toward the outer peripheral direction as in the past.

[0044] The wind power generation device 5 is fixed to the upper part of a support column 7, and the support column 7 is fixed to a support plate (not shown). The support plate is a plate for supporting the wind tunnel 6 and the support column 7, and is buried near the bottom of the wind tunnel 6 in an integrated manner with the wind tunnel 6. In addition, the support plate is provided with feet (not shown) that pass through the bottom of the wind tunnel and face downward, and the wind tunnel 6 and the wind power generation device 5 are fixed by fixing the feet to a specified installation surface.

[0045] The impeller 11 is arranged on the air intake side of the support column 7. With such a structure, it is possible to generate the turbulence of the wind flow caused by the support column 7 at a position sufficiently far from the impeller 11, so that the reduction of the acceleration effect near the impeller 11 can be suppressed.

[0046] If the flow of the wind after passing through the impeller becomes turbulent due to, for example, the wake generated behind the blade 13 or the strut 7, or the Karman vortex generated when the wind separates from the surface of the strut, a velocity component other than the traveling direction is generated in the wind, and the flow of the wind slows down behind the impeller inside the wind tunnel. In such a case where such wind turbulence occurs, even if the cross-sectional shape of the wind tunnel is substantially streamline, it is not possible to sufficiently increase the speed of the wind flowing into the inside of the wind tunnel 6 from the suction port, and it may not be possible to obtain the expected high power generation efficiency. Therefore, it is preferable to minimize the influence of such wind turbulence on the power generation efficiency as much as possible.

[0047] In addition, the impeller 11 is preferably arranged such that the wind-facing surface of the blade 13 faces the front end portion 61 on the suction port side. With such a structure, the impeller 11 can efficiently receive the wind that has flowed into the inside of the wind tunnel from the suction port and has increased in speed, and the power generation amount and the power generation efficiency can be improved.

[0048] In addition, the impeller 11 is preferably arranged such that the rotation axis 2 of the impeller 11 is along the central axis 64 of the wind tunnel 6 inside the wind tunnel 6. With such a structure, the impeller 11 can efficiently receive the wind that has flowed into the inside of the wind tunnel from the suction port and has increased in speed, and the power generation amount and the power generation efficiency can be improved.

[0049] Furthermore, when the rotation radius of the blade 13 of the impeller 11 is R, the inner diameter of the minimum inner diameter portion 62 of the wind tunnel 6 is preferably 3R or less, more preferably 2.6R or less, and further preferably 2.2R or less within the range of not becoming 2R or less. With such a structure, the wind flowing into the inside of the wind tunnel from the suction port can be multiplied / speeded up most efficiently near the impeller 11, and the power generation amount and the power generation efficiency can be improved.

[0050] Explanation of reference numerals

[0051] 11... impeller, 12... hub, 13... blade, 2... rotation axis, 3... spur gear, 31... shaft, 4... planetary gear, 5... wind power generation device, 6... wind tunnel, 61... front edge, 62... minimum inner diameter portion, 63... rear end portion, 64... wind tunnel central axis, 65... collecting cable, 7... strut, 8... generator, 9... torque limiter.

Claims

1. An impeller for wind power generation, comprising: a plurality of blades; and a hub having a rotating shaft provided at the center and the plurality of blades circumferentially arranged at equal intervals, the blades being formed to extend while expanding in width toward the outer periphery of the impeller, the length of a line segment connecting the intersection of lines respectively extending the leading edge and the trailing edge of the blade and the intersection of the leading edge of the blade and the outer peripheral edge being different from the length of a line segment connecting the intersection of lines respectively extending the leading edge and the trailing edge of the blade and the intersection of the trailing edge of the blade and the outer peripheral edge, the line segment connecting the leading edge and the trailing edge of the blade being inclined at 10 degrees or more and 20 degrees or less with respect to a plane perpendicular to the rotating shaft of the impeller, when viewed from the front of the impeller, a part of the trailing edge of the blade in front of the rotation direction of the impeller overlaps with the leading edge of the blade behind the rotation direction.

2. The impeller for wind power generation according to claim 1, wherein, the plurality of blades are five in number, when viewed from the front of the impeller, the blade in front of the rotation direction of the impeller and the blade behind the rotation direction do not overlap at the outer peripheral portion of the impeller.

3. The impeller for wind power generation according to claim 1 or 2, wherein, the blades are formed of a plate-like material having an equal thickness, and the windward side surface is a plane.

4. A wind power generation system, comprising a wind power generation device, the wind power generation device at least having: a wind tunnel formed with a streamline-shaped longitudinal section cut along a central axis; the impeller according to any one of claims 1 to 3, disposed in the wind tunnel; and a generator for generating electricity by the rotation of the impeller.

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