JP2002266748A - Windmill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drag type windmill capable of extremely efficiently providing general energy without spoiling advantages such as rotating performance under weak wind, high torque in a low-speed rotating area, quiet and structural simplicity in rotating. SOLUTION: This windmill 1 is formed by attaching multiple vanes 2 formed of first blades 5 and second blades 6 about a rotary shaft 3 and each of the first and the second blades 5 and 6 is provided with a joining end edge 8, a spiral end edge 7, and an opening end edge 9. The vane 2 is formed by joining the first blade 5 and the second blade 6 at respective joining end edges 8, and respective spiral end edges 7 and 7 of the first and the second blades 5 and 6 are fixed onto the rotary shaft 3 so that the vane 2 is fitted to the rotary shaft 3. This windmill is also characterized in that an opening part 4 for receiving the wind is formed of opening part end edges 9 of the first and the second blades 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a wind power generation facility,
The present invention relates to a wind turbine that can be used as a power source of a pumping facility or the like, and more particularly, to a drag-type wind turbine that has rationally shaped blades formed using a “tangential curved surface” that can be geometrically defined.

[0002]

2. Description of the Related Art A windmill is a device that uses a wind force to rotate a rotating body to obtain kinetic energy, that is, a device that converts natural energy called wind power into rotational energy that can be used as a power source of a machine or the like. There are two types of wind turbines: lift-type wind turbines, such as propeller type, and drag-type wind turbines.

[0003] Propeller type wind turbines are the most widely used type of wind turbines in wind power plants and the like because of their excellent energy conversion efficiency. Particularly, since kinetic energy can be efficiently obtained under a strong wind, it is mainly used in a place where a strong strong wind blows.

FIG. 10 shows a general propeller type wind turbine 100.
Is a simplified illustration of the structure of FIG. In this drawing, 101 is a propeller, and 102 is a rotating shaft held in the horizontal direction.

When the propeller 101 receives the force of the wind, it rotates around the rotation axis 102. In order to obtain the rotational kinetic energy most efficiently in such a propeller type wind turbine, the rotating surface must be oriented in the wind direction. It is necessary to hold the propeller 101 in a direction that is always orthogonal to the propeller 101. Therefore, this type of propeller type windmill 100 includes
Usually, a mechanism (direction control mechanism) capable of changing the direction of the propeller 101 according to a change in the wind direction is provided.

[0006] On the other hand, a drag type windmill has the advantages that it rotates well even in a weak wind, can generate high torque (rotational force) in a low speed rotation range, and has a peripheral speed ratio. Since it does not exceed 1, it is excellent in safety against high winds and quietness. In addition, since wind from all directions can be used, a direction control mechanism or the like which is likely to cause a failure is not required, and the structure of the windmill can be simplified,
As a result, maintenance is extremely easy and economical. For this reason, drag-type wind turbines are used for home-use, small-scale pumping facilities, power generation facilities, and the like in developing countries or regions with weak winds.

FIG. 11 shows a general wind turbine of a drag type.
1 shows a simplified structure of a Savonius type windmill 200. As shown, the Savonius type windmill 200 includes a rotating shaft 207 held substantially vertically, and curved blades 201 and 202 having a circular cross section.

[0008] In this type of drag type wind turbine, when a wind is received from one direction, the blades rotate around a rotation axis due to a "difference in drag (air resistance)" generated between the blades. I have.

More specifically, in FIG. 11, a Savonius type windmill 200 is moved from the near side (ie, in the direction of arrow K).
When the wind blows, the blade 201 on the left side in the figure receives the wind on the opening 201a side, and a force to rotate in the direction of arrow J1 in the figure acts, while the blade on the right side in the figure At 202, the wind is received on the back surface 202b side, and a force to rotate in the direction of arrow J2 in the drawing acts, but the opening 201a side has
Since the effect on the wind is greater than that on the back surface 202b side, the blades 201 and 202 eventually rotate in the direction of the arrow J1.

[0010]

SUMMARY OF THE INVENTION A propeller type windmill is
As described above, energy conversion can be performed efficiently under strong winds, but the conversion efficiency decreases under weak winds, so that areas where strong winds are blowing stably (more specifically, Where the average annual wind speed exceeds 5 m / sec).

When the rotation speed of the windmill increases, noise caused by wind noise may become a problem, and it is not suitable for use in a living area from the viewpoint of safety. Furthermore, a directional control mechanism and a safety device for stopping the operation of the wind turbine when the wind speed exceeds a specified level are required, so that the structure is complicated, and the manufacturing cost, the maintenance cost, and the maintenance work are easy. There is a problem in such points.

On the other hand, the Savonius type wind turbine 200 as shown in FIG. 11 has a disadvantage that the energy conversion efficiency is not so high as compared with the propeller type wind turbine. Also, in order to eliminate such disadvantages, those with an increased number of blades, those in which the blades are stacked up and down to form a multi-stage system, those in which the blades are twisted to eliminate the dead point of torque, etc. Various types of improved Savonius type wind turbines have been devised, but all of them can be expected to slightly improve performance, but they lose the simplicity of structure, which is the original advantage of drag type wind turbines. I have.

Further, in the Savonius type windmill, if the shape on the back side can be configured so as to minimize the drag against the wind, it is possible to smoothly rotate the wind turbine. Is often formed into a curved surface. For example, a curved surface is formed by processing a plate-shaped material such as a plywood or a metal plate (particularly, considering aerodynamic characteristics and the like, a reasonable and precise Form a curved surface designed based on calculations based on design values.)
Is often difficult.

More specifically, in order to form a curved surface that draws a delicate curve by processing a plate-like material, it is necessary to manufacture a "mold" in advance, and the number of working steps is large. In addition, the manufacturing cost increases.

The present invention has been made in order to solve such a problem, and it is possible to easily and economically manufacture a drag type wind turbine without using a "type". Regardless, it has blades that have a reasonable and subtle curved surface shape, and the drag type windmill has been equipped with low wind speed, high torque in the low speed rotation range, quietness during rotation, structure It is an object of the present invention to provide a drag type wind turbine capable of efficiently obtaining rotational energy having high versatility without impairing advantages such as simplicity of the wind turbine.

[0016]

A wind turbine according to the present invention comprises a plurality of blades formed by a first blade and a second blade mounted around a rotation axis. Blade has a joining edge, a spiral edge, and an edge for an opening, respectively, and the blade has a first blade and a second blade at each joining edge. The first and second blades are fixed on the rotating shaft so that the blades are attached to the rotating shaft.
By the opening edges of the first and second blades,
An opening for receiving the wind is formed.

In the case where the surface of the first blade and / or the surface of the second blade forms a tangential curved surface, a blade having a reasonable shape is required to have a “mold”. Without using a flat member, and
It can be manufactured economically.

Alternatively, the wind turbine according to the present invention can be constructed by attaching a plurality of blades formed by stretching a cloth material to a frame around the rotation axis instead of the blades. In this case, the structure can be simplified. It can be.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a wind turbine according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a wind turbine 1 according to a first embodiment of the present invention, and FIG. 2 is a plan view thereof. As shown in these figures, this wind turbine 1 basically has three blades 2a, 2a.
b, 2 c and the rotating shaft 3.

As shown, the three blades 2a to 2c are all oriented in the same direction around the rotation axis 3, and
Each is equally spaced. When the windmill 1 receives wind from a certain direction, the windmill 1 receives the wind at the opening 4 of any one of the blades 2, and a specific direction (R direction in FIGS. 1 and 2) is generated by the force of the wind.
It is designed to rotate.

FIG. 3 is a perspective view of the blade 2 used in the wind turbine 1 shown in FIGS. 1 and 2, and FIG. 4 is a plan view thereof. As is clear from FIG. 3, the blade 2
It is composed of a first blade 5 and a second blade 6. Each of the first blade 5 and the second blade 6 has a helical edge 7, a joining edge 8, and an opening edge 9, respectively, and is a curved surface having these as an outer peripheral line. 10.

The first blade 5 and the second blade 6 are mirror-reflected with respect to each other with respect to a horizontal plane.
The blade 2 is configured. The blades 2 are attached to the rotating shaft 3 by fixing the spiral edges 7, 7 shown in FIG. 3 on the outer peripheral surface of the rotating shaft 3 shown in FIGS. 1 and 2.

In addition, by attaching the blade 2 to the rotating shaft 3 in this manner, the opening edge 9 of the blade 2,
9 (and a part of the rotating shaft 3) forms an opening 4 around the rotating shaft 3 for receiving the wind.

The curved surfaces 10 constituting the first blade 5 and the second blade 6, respectively, are configured to form "tangential curved surfaces". The “tangential curved surface” is one of the curved surfaces that can be geometrically defined, and is particularly important for understanding the structure of the blade 2 in the present embodiment, and will be described in detail below.

The tangent curved surface is a helical line C1, shown in FIG.
It is a curved surface configured with the straight line C2 and the involute curve C3 as the outer peripheral lines. Among these lines, the helix line C1 is a line segment existing on the outer peripheral surface of the cylinder S having a diameter d1 and a height d2, and is a point A and a point B shown in FIG.
Is a line connecting the shortest distance in a predetermined circumferential direction. still,
Point A is an arbitrary point present on the outer circumferential circle of the upper surface S1 of the column S, and point B is a point present at an arbitrary position on the outer circumferential circle of the bottom surface S2.

The straight line C2 is a line connecting the points E and A shown in FIG. 5, and the length thereof is the same as the helix line C1. The point E is a point existing on the same plane Q as the bottom surface S2 of the cylinder S, and a point on a tangent line G (tangent line of the outer peripheral circle of the bottom surface S2) passing through a point F located vertically below the point A. It is.

The involute curve C3 is a curve existing on the same plane Q as the bottom surface S2 of the cylinder S, and is a line connecting the points E and B according to a certain rule. Here, how to draw the involute curve C3 will be described. First, a yarn H having the same length as the helix line C1 is prepared.
It arrange | positions on the winding line C1. Then, as shown in FIG. 6, the thread H is released from the cylinder S in order from the point B side. The release of the thread H is such that the end point H1 on the point B side always moves on the plane Q, and the portion released from the cylinder S is
It is always performed as a straight line as a tangent to the cylinder S.

In this manner, when the yarn H is released from the point B until the end point H1 intersects the tangent line G, the end point H
The locus (curve) drawn on the plane Q by 1 is the involute curve C3. In the process of the release, the curved surface that the yarn H continuously draws in the space is a “tangential curved surface”.

In the present embodiment, the first blade 5
And the curved surface 10 configuring the second blade 6 respectively,
It is configured to form the “tangential curved surface” as described above. In addition, the first and the second shown in FIGS.
The helical edges 7 of the blades 5 and 6 correspond to the helix line C1 shown in FIG. 5, and similarly, the opening edges 9 and the joining edges 9 of the first and second blades 5 and 6. The edge 8 is shown in FIG.
, And an involute curve C3.

The wind turbine 1 according to the present embodiment has the following configuration, but has the following advantages as compared with the conventional Savonius type wind turbine. First, the first advantage is that the blade 2 exhibiting a reasonable curved shape can be easily manufactured from a single plate-like material without using a “mold”. The second advantage is that since the rear side of the blade 2 is wedge-shaped, the drag to be applied to the blade 2 is effectively reduced when the rear side is directed to the windward direction. It is possible to make it.

Here, in order to more specifically explain these advantages, an example of a method of manufacturing the wind turbine 1 in the present embodiment will be described. First, feather 2 to be made
Size and shape are determined. The blades 2 are formed by joining the first blade 5 and the joining edges 8,
The first blade 5 and the second blade 6 are formed by joining the spiral edge 7, the joining edge 8, and the opening edge 9 with the outer peripheral line. Each of the curved surfaces 10 is formed.

Therefore, the size and shape of the blade 2 are as shown in FIG.
And the length dimension of the spiral edge 7, the joining edge 8, and the opening edge 9 of the first blade 5 (or the second blade 6) shown in FIG. Blade 5 and second
Can be determined by defining basic factors such as the angle (2θ) of the internal angle at the joint portion of the opening edges 9, 9 of the blade 6, and the radius (Y) of the helix of the spiral edge 7. . The “radius of the helix” as used herein refers to the radius of a circle formed by projecting the helix on a horizontal plane. For example, in FIG. 4 showing a plan view of the blade 2, the spiral edge 7 is drawn. This refers to the radius Y of the arc line.

These basic elements are, of course,
The size and size of the windmill desired by the maker can be arbitrarily determined depending on the shape, but in the present embodiment, among the basic elements thereof, so that the rotation energy can be obtained most efficiently by the rotation of the windmill. The “angle (2θ) of the inner angle at the joint of the opening edges 9, 9” is set to “70 °”. The reason is that when this angle is set to 70 ° (more precisely, 70.528 ° (± 5 °)), it is theoretically considered that the torque obtained by the rotation of the windmill becomes maximum. . Hereinafter, the theoretical basis for setting this angle to 70 ° will be described.

First, the amount of wind received by the blades 2 of the wind turbine 1 at the openings 4 is uniform. For example, a plane forming the openings 4 (the two opening edges 9 and 9 and the rotating shaft 3). The amount of wind received at a position near the joining edge 8 in the isosceles triangular plane formed by the
The length of the opening edge 9 is assumed to be “1”, and the angle of the inner angle at the joint of the opening edges 9 is “2θ”. ", The area" A "of the opening 4 can be represented by the following" Formula 1 ".

[0035]

(Equation 1)

Next, the first moment of the plane forming the opening 4 is calculated, and the torque "M" is obtained by the following equation.

[0037]

(Equation 2)

Then, when the above-mentioned “Equation 2” is differentiated by “θ” and the limit value is obtained, the following is obtained.

[0039]

(Equation 3)

[0040]

(Equation 4)

Of the solutions thus obtained, “θ”
Should be larger than 0 and smaller than π / 2, so the first solution is adopted. Then, when the approximate value is calculated, the following expression is obtained.

[0042]

(Equation 5)

As in the above “Equation 5”, “θ” is 35.2.
When the angle is set to 64 ° (that is, the angle “2θ” of the inner angle at the joining portion of the opening edges 9, 9 is set to 70.528 °)
It is considered that the torque of the wind turbine 1 is maximized.

In the present embodiment, the angle (2θ) of the inner angle at the joint of the opening edges 9 is set to 70 ° (± 5 °) based on such a theoretical basis. I have. When the design of the blade 2 is completed by setting the dimensions of the other basic elements in addition to the setting of the angle of the inner angle, the first blade constituting the blade 2 is then set based on the design value. 5 and the second blade 6 are manufactured.

Incidentally, the "tangential curved surface" constituting the first blade 5 and the second blade 6 according to the present embodiment.
Is known as a fact that has been mathematically proven to be "extensible". This "developable surface" is a curved surface that can be developed into a flat surface. Considering that the "tangent surface" is a "developable surface", on the contrary, the "tangent surface" is a flat material. Can be easily formed by curving.

As described above, the first blade 5 and the second blade 6 according to the present embodiment
Are configured to form a "tangential surface",
By simply bending a single plate-shaped material cut into a predetermined shape, it can be easily formed without the need for a “mold”.

In view of the above, the windmill 1 in the present embodiment is formed by cutting a flat wooden plate and attaching it to a predetermined position on the outer peripheral surface of the rotating shaft 3 so as to be curved. A plurality of blades 2 are formed by forming a first blade 5 and a second blade 6 having curved surfaces on the outer peripheral surface of the rotating shaft 3 and joining them at joining edges 8, 8. Is formed.

Specifically, first, the first
The figure which shows the state which unfolded the blade 5 on a plane was drawn, and according to this figure, a flat wooden board material is cut | disconnected. Next, the cut wooden board is attached at a predetermined position on the outer peripheral surface of the rotating shaft 3. When attaching the wooden plate 5a to the rotating shaft 3,
As shown in FIG. 7, a target mounting position X of the wooden plate is specified in advance on the outer peripheral surface of the rotating shaft 3 based on the design value, and the upper arc portion 7a of the wooden plate 5a is moved along the target position X. Then, the first blade 5 is formed on the rotating shaft 3. At this time, if the display of the target position X is as designed, the wooden board 5a is to be mounted on the rotating shaft 3 in a curved state, and the curved surface should be a "tangential curved surface". is there.

After forming the first blade 5 having a tangential curved surface on the rotating shaft 3 in this manner, the second blade 6 is formed below the first blade 5 according to the same procedure. . And each joining edge 8,8
Can be easily manufactured, as shown in FIG. 1, a wind turbine 1 in which a plurality of blades 2 are formed around a rotation axis 3.

The mounting of the wooden plate 5a on the rotating shaft 3 does not necessarily mean that the entire arc-shaped portion 7a has to be fixed on the rotating shaft 3. For example, both ends of the arc-shaped portion 7a are required. Only 30 and 31 (see FIG. 7) may be fixed on the rotating shaft 3. Also, the first blade 5
And the joining edges 8, 8 of the second blade 6 are
As described above, this may be performed after the wooden plate is attached to the rotating shaft 3. However, the two wooden plates to form the first blade 5 and the second blade 6 are partially joined to each other, and then Thus, it may be mounted on the rotating shaft 3.

The first blade 5 and the second blade 6 in this embodiment are formed of a flat wooden plate as described above, but have sufficient strength to ensure the function as the blade of the wind turbine. And a flexible material that is easily deformed into a curved surface, for example, can be formed using a plastic plate or a metal plate.

Further, in the present embodiment, three blades 2 are mounted around the rotation shaft 3, but four or more blades 2 may be mounted. In addition, the wind received at the opening 4 is configured to pass through the blades 2 and the rotating shaft 3 and pass to the opposite side, so that the blades 2 other than the blades 2 receiving the wind also apply thrust. A structure (a so-called “cross-flow type” structure) can also be used.

In this embodiment, the blade 2 is attached to the rotating shaft 3 by fixing the spiral edge 7 directly on the outer peripheral surface of the rotating shaft 3. However, you may comprise so that it may be indirectly attached to the rotating shaft 3 via a fixture etc. In this case, the outer peripheral surface of the rotating shaft 3 may be formed by a curved surface that does not necessarily match the curvature of the spiral edge 7.

As described above, the wind turbine according to the present embodiment has blades exhibiting an ideal curved surface shape in consideration of air resistance and the like.
Without using a "mold", it can be manufactured faithfully and easily with design values. Therefore, the manufacturing process can be simplified, and it is possible to flexibly cope with a change in the design of the wind turbine and the like. Further, the efficiency can be improved without a complicated additional device. In addition, even under strong wind, the wind can escape and the vehicle can be driven safely.

Next, a wind turbine according to a second embodiment of the present invention will be described. The windmill according to the present embodiment is characterized in that a cloth material is used as a material forming the blade. FIG. 8 shows a windmill 31 according to the present embodiment. This windmill 31 basically has three blades 32a,
32b, 32c, the rotating shaft 33, and three fixtures 40
a, 40b, and 40c.

The three blades 32a to 32c are all arranged around the rotation axis 33 in the same direction and at equal intervals, similarly to the wind turbine 1 in the first embodiment. When the wind turbine 31 receives wind from a certain direction, it rotates in a specific direction (the direction of R in FIG. 8).

The blades 32a to 32c are connected to the first blade 3
5 and a second blade 36. First blade 35 and second blade 36
Are mirror images of each other with respect to a horizontal plane as in the first embodiment. In each case, the spiral edge 7, the joining edge 8, and the opening edge 9 are It is constituted by a tangent curved surface as an outer peripheral line.

The fixing members 40a to 40c are made of a metal having a sufficient strength as a member for fixing the blade 32 of the wind turbine 31 and having a small deflection (or a known material corresponding thereto). And these fixtures 40a-4
0c has a shape having three vertices as shown in the present embodiment, and has a structure capable of fixing the blades 32a to 32c at each of the vertices. I have.

More specifically, the fixture 40a and the fixture 40c fix the upper end and the lower end of each of the blades 32a to 32c to the rotating shaft 33, respectively.
b is configured to fix one end of the joining edge 8 of the blades 32 a to 32 c to the rotating shaft 33.

The first blade 35 and the second blade 36 in this embodiment are made of a cloth material, and the outer periphery thereof (spiral edge 7, joining edge 8,
In addition, by forming the opening edge 9) with a frame and a wire, the structure is such that a special three-dimensional shape of a tangential curved surface can be maintained. Hereinafter, the structure will be specifically described.

As the cloth material used in the present embodiment, natural fibers, synthetic fibers, nonwoven fabrics, plastic films (or sheets) and the like can be used. It is desirable to use a cloth material having sufficient strength and durability to ensure the function. In particular, since windmills are used outdoors,
It is desirable to use a material having excellent weather resistance, such as a tent or a canvas, and it is more desirable to apply a fluorine process to the surface of the fabric to be used so as to obtain higher weather resistance.

FIG. 9 shows the structure of the first blade 35 together with the structure of the rotating shaft 33 and the fixture 40 and the like in detail. In this figure, reference numeral 41 denotes an opening edge 9.
The straight frame 42 for fixing the first blade 35 at the first edge 3 at the joining edge 8
5 is an involute frame for fixing 5.
The straight frame 41 and the involute frame 42 are made of a metal having a sufficient strength as a member constituting a blade of a windmill and having a small deflection (or a known material corresponding thereto). Also, 43
Is a wire for fixing the first blade 35 at the spiral edge 7.

The first blade 35 has a spiral edge 7,
In addition, blind holes are provided in the entire length of the opening edge 9, and each blind hole has a structure that allows the wire 43 and the straight frame 41 to pass through the blind hole. Has become.

The involute frame 42 has a shape conforming to the joining edge 8 in order to fix the first blade 35 at the joining edge 8. Note that in FIG.
2a is the tip of the involute frame 42,
42b is the base end. The involute frame 42 is attached to the fixture 40b at the base end 42b as shown.

The straight frame 41 has a linear shape, passes through a blind hole provided at the opening edge 9, and has one end connected to the fixture 40a and the other end. The part is attached to the end 42 a of the involute frame 42.

The wire 43 passes through the blind hole provided at the spiral edge 7, and one end is connected to the fixture 40 a and the other end is connected to the base end 42 b of the involute frame 42. It is attached. Wire 43
Is made of a flexible metal (or a known material corresponding thereto) having a sufficient strength as a member constituting the blade of the wind turbine, so that the shape of the spiral edge 7 of the first blade 35 is And the fixture 40 is bent in that state.
a, 40b.

As described above, the first blade 35 of the wind turbine 31 according to the present embodiment is configured such that the cloth material cut into a predetermined shape is formed of the wire 43 held between the fixtures 40a and 40b, and the fixture 43. A straight frame 41 and an involute frame 4 having one end fixed to each of 40a and 40b
By being stretched between the two, the structure is fixed around the rotation axis 33 and can maintain a special three-dimensional shape of a tangential curved surface.

Then, the wind turbine 31 in this embodiment is
As shown in FIG. 8, the blades 32 a to 32 c are formed around the rotation axis 33 by the first blade 35 and the second blade 36 having a substantially similar structure, and
With such a structure, the same effect as that of the wind turbine 1 of the first embodiment can be expected.

Further, according to the present embodiment, when attaching the cloth material to the rotating shaft 33, a special three-dimensional shape called a tangential curved surface is inevitably formed. After forming, it is not necessary to attach to the rotating shaft 33, so that the manufacturing process can be simplified. Also,
The cloth material used as a material for the blades constituting the blades 32 is light, has excellent forming workability, and is easy to obtain a large material. Therefore, the cloth material is suitable for manufacturing large-sized blades. It is possible to cope with an increase in the size of the device.

[0070]

According to the present invention, a windmill blade having a reasonable three-dimensional shape can be obtained from a commercially available flat material such as plywood, plastic plate, or plywood without the need for a "mold". Can be produced. Therefore, it is possible to expect an effect that the windmill can be easily manufactured at low cost.

Further, since it is a drag type windmill, it has advantages such as rotation in a weak wind, high torque in a low speed rotation range, and simplicity of the structure. It is possible to In addition, it has high quietness during rotation, and can be used in a residential area of people.

Further, by using cloth as a material for the blades of the wind turbine, it is possible to reduce the weight of the blades and improve the rotation efficiency of the wind turbine. Also, unlike other materials,
Since a curved surface is not required to be deformed when manufacturing the blade, the blade can be manufactured easily. Also, if it is cloth,
It is particularly useful for large size windmills because large size materials are readily available and do not require curved surface processing.

[Brief description of the drawings]

FIG. 1 is a perspective view of a wind turbine 1 according to a first embodiment of the present invention.

FIG. 2 is a plan view of the wind turbine 1 of FIG.

FIG. 3 is a perspective view of a blade 2 of the wind turbine 1 of FIG.

FIG. 4 is a plan view of the blade 2 of FIG. 3;

FIG. 5 is an explanatory diagram of a “tangential curved surface” defined geometrically.

FIG. 6 is an explanatory diagram of a “tangential curved surface” defined geometrically.

FIG. 7 is an explanatory view of a method of manufacturing the wind turbine 1 of FIG.

FIG. 8 is a perspective view of a windmill 31 according to a second embodiment of the present invention.

FIG. 9 is a structural diagram of a wind turbine 31 of FIG.

FIG. 10 is a perspective view of a conventional propeller type wind turbine 100.

FIG. 11 is a perspective view of a conventional Savonius type windmill 200.

[Explanation of symbols]

 1: wind turbine, 2a, 2b, 2c: blade, 3: rotating shaft, 4: opening, 5: first blade, 6: second blade, 7: spiral edge, 8: joining edge, 9: edge for opening, 10: curved surface, 30, 31: end, 32a, 32b, 32c: blade, 33: rotating shaft, 35: first blade, 36: second blade, 40a, 40b, 40c: Fixing tool, 41: Straight frame, 42: Involute frame, 43: Wire,

Claims (3)

[Claims] 1. A windmill comprising a plurality of blades formed by a first blade and a second blade attached around a rotation axis, wherein the first and second blades are connected to a joining edge. A helical edge and an edge for an opening, respectively, wherein the blade is formed by joining a first blade and a second blade at each joining edge. And by fixing each spiral edge of the second blade on the rotation axis, the blade is attached to the rotation axis. By the opening edge of the first and second blades,
A windmill having an opening for receiving wind. 2. The wind turbine according to claim 1, wherein a surface of the first blade and / or the second blade forms a tangential curved surface. 3. A windmill comprising a plurality of blades formed by stretching a cloth material on a frame, the plurality of blades being attached around a rotation axis, wherein the surface of the cloth material stretched on the frame forms a tangential curved surface. A windmill characterized by the following.