JP2001073925A - Windmill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start of rotation of a windmill by only wind force without necessitating other starting means by connecting a shaft which is disposed in parallel with a main shaft of the windmill in blades for receiving wind, to a wind receiving plate disposed adjacently to the blades by power transmitting means, in a vertical shaft windmill having a rotary shaft which is disposed perpendicularly to wind. SOLUTION: A vertical shaft windmill has a pair of blades 3 disposed symmetrically to a main shaft 1, the both blades 3 are supported around the main shat 1 freely to turn by upper and lower arms 2a, 2b. A gear 6 is fixed to an upper end of each blade 3, a gear 8 is fixed to a shaft 10 of a dog vane plate 4 disposed on a tip end of a bending part of each end of the arm 2a, and the gears 6, 8 are interlocked with each other through a belt 9. Namely, when an angle of the dog vane plate 4 is changed by receiving wind force, the blade 3 is interlocked so as to rotate at only a half-angle in the rotational direction, the blade 3 is rotated so as to receive wind at a proper angle at all times, and the main shaft 1 is rotated by turning of the blade 3 receiving wind.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind turbine used for wind power generation and the like, and more particularly to a wind turbine having a rotation axis perpendicular to the wind.

[0002]

2. Description of the Related Art There are two types of wind turbines that convert wind energy into rotational energy, such as a propeller-type horizontal axis type in which the axis of rotation is parallel to the wind, a Savonius type, a Darius type, etc. There is a vertical axis type with. The former high-speed propeller-type wind turbine has a high efficiency of converting wind energy into rotational energy, that is, high wind turbine efficiency, and is already widely used for wind power generation. The need to provide a mechanism that rotates the entire machine in the direction of the wind always increases costs. Further, it becomes difficult to quickly change the direction of the wind turbine when the wind turbine is large, and there is a problem that the efficiency of the wind turbine is reduced when the wind direction changes frequently.

[0003] The vertical axis type windmill does not need to move the rotating shaft depending on the wind direction, so there is no problem as described above, and it is structurally advantageous such that the power generator can be placed under the windmill. A windmill utilizing drag, such as the Savonius type, has a low efficiency and is not practical, whereas a Darrieus type windmill utilizing lift has high efficiency and has been practically used in some cases.

[0004]

A Darrieus-type wind turbine generates a large torque when rotating at high speed, and exhibits high wind turbine efficiency. However, on the other hand, the torque at the time of low-speed rotation is extremely small, and hardly any torque is generated, especially at rest, so that it cannot start rotating spontaneously due to the wind. For this reason, there is a particular inconvenience that another windmill, a motor, and the like must be used to start the windmill, which hinders the popularization of the Darius type.

[0005]

The wind turbine according to the present invention is a vertical axis wind turbine having a rotation axis perpendicular to the wind, similarly to the Darrieus type wind turbine, and the blade receiving the wind has a predetermined distance from the main axis (rotation axis) of the wind turbine. At a distance so that it is rotatable about an axis parallel to the main axis, the axis of the blade is
It is connected to a weather vane installed adjacent to the blade by power transmission means, the blade rotates by half the angle of rotation of the weather vane, and the line connecting the main axis of the windmill and the blade is perpendicular to the line. Then, the adjacent blade and the weather vane are connected so as to be vertical or parallel.

Thus, even when wind comes into contact with the blade from almost any direction, the angle of the blade is changed by the weather vane, and torque is always efficiently generated in one rotation direction. Also, the weather vane installed next to the blade,
Since the angle is changed according to the relative wind speed that changes according to the moving speed of the blade due to the rotation of the windmill, an effective torque is generated regardless of the magnitude of the rotation speed of the windmill.

[0007]

FIG. 1 is a perspective view showing an example of a wind turbine according to the present invention having two blades, and FIG. 2 is a plan view seen from above. This windmill is a vertical axis windmill having the main shaft 1 as a rotation axis. The two units including the blade 3, the weather vane 4, the gear 6, and the like arranged symmetrically with respect to the main shaft 1 are completely equivalent, and are held by upper and lower arms 2a and 2b.

FIG. 3 is an enlarged view of the vicinity of the blade in FIG. The blade 3 is fixed to a gear 6 and is rotatable about a shaft 7. The weather vane 4 is connected to a gear 8 through a shaft 10. Further, the gear 6 and the gear 8 are linked via a belt 9. Here, the number of teeth of the gear 6 is double that of the gear 8, and as a result, if the angle of the weather vane 4 changes, the blades 3 are linked so as to rotate by half the angle in the same rotation direction. The weight 5 on the opposite side of the weather vane 4 prevents the wind vane from changing its angle under the influence of the centrifugal force during rotation of the windmill. It has been adjusted to be.

Next, the force acting on the blade 3 in the case of receiving winds from various directions will be described with reference to FIG. In the figure, the wind speed is indicated by a white arrow, and the force is indicated by a black arrow. FIGS. 4A and 4C show the case where the wind velocity vector is perpendicular to the line connecting the main shaft and the blade. At this time, since the weather vane is rotated by 180 degrees, the blade is rotated by 90 degrees by the mechanism described above. According to the conditions shown in the claims, in FIG. Parallel to the vector,
(B) is vertical. This is the condition for a windmill rotating clockwise.

In FIG. 1A, a drag for generating a counterclockwise torque acts on the blade 3, but this is a condition where the drag received from the wind is the smallest, and this torque is slight.

In (B), the weather vane 4 faces in a direction rotated 90 degrees counterclockwise from (A), and the blade 3 turns 45 degrees in the same direction. As a result, a lift and a drag act on the blade 3, and a particularly effective clockwise torque is generated by the lift.

In (C), as described above, the blade 3 is perpendicular to the wind speed vector, and receives a large drag to generate a clockwise torque.

Finally, in (D), the weather vane 4 is rotated 90 degrees counterclockwise from (C), and the blade 3 is moved in the same direction.
Turn 5 degrees. As a result, a lift and a drag act on the blade 3, and a particularly effective clockwise torque is generated by the lift.

The above description has been made under the conditions of the four wind directions. However, except for the case where the condition is actually close to (A),
For winds from most directions, the blades 3 generate a clockwise torque. As described above, in the wind turbine of the present invention, by changing the angle of the blade in conjunction with the weather vane adjacent to the blade, torque in the same rotational direction is effectively generated.

The vertical axis wind turbine of the present invention has two different rotation modes. One is a low-speed rotation mode when the blade speed rω (r: rotation radius of the blade, ω: angular speed) is smaller than the wind speed V (V is the wind speed viewed from the stationary system, not the relative wind speed received by the blade). It is. FIG. 5 shows the state of the rotation of the windmill, the angle of the blade, and the force acting on the blade in this mode. Arrow d indicates the direction of rotation.
In the low-speed rotation mode, the windmill rotates using both drag and lift received from the wind. In the drawing, when the position of the blade is represented by a rotation angle θ, a clockwise torque is generated at any other position except that a weak torque that hinders rotation is generated near θ = 0. As a result, the present vertical axis wind turbine has a feature of smoothly starting and accelerating to a high speed rotation at a stationary time and at a low speed rotation, and this point is definitely different from a Darrieus type wind turbine.

Accelerate in low-speed rotation mode, blade speed r
When ω exceeds the wind speed V, the windmill shifts to the high-speed rotation mode. FIG. 6 shows the state of the rotation of the windmill, the angle of the blade, and the force acting on the blade in the high-speed rotation mode. In most parts except where the blade position is around θ = 0 and 180 degrees,
A large lift acts on the blade, and a part of this acts as torque. As described above, in the high-speed rotation mode, the present windmill is a lift windmill that rotates by using lift, like the Darrieus windmill. In this mode, the wind turbine further accelerates, and the blade speed reaches several times the wind speed V or more.

The vertical axis wind turbine according to the present invention can be used in the above-described low-speed rotation mode. However, in order to increase the efficiency of the wind turbine at low-speed rotation, the blade width is increased to increase the area for receiving wind. Need to be taken. This is not a big problem for small wind turbines, but it is disadvantageous in increasing the size of wind turbines for practical wind power generation in terms of strengthening the structure that supports the weight of the blades and countermeasures against strong winds.

On the other hand, in the high-speed rotation mode, the maximum windmill efficiency can be obtained with a blade having a relatively small width, which is advantageous for increasing the size. The vertical axis wind turbine of the present invention is mainly used in a high-speed rotation mode.

In the high-speed rotation mode, the vertical axis wind turbine of the present invention is completely a lift wind turbine. At this time, in order to generate a larger lift force on the blade, it is more preferable that the cross-sectional shape of the blade is asymmetrical 3s than the shape 3 in FIG. 7 and that the rounded side faces the windward side. However, in the embodiment shown in FIG. 3, since it is uncertain which side of the blade faces upwind, FIG.
Not suitable for using asymmetric blades. When using an asymmetric blade such as 3s, as shown in FIG. 8, a pin 11 for restricting the movement of the weather vane 4 is introduced,
The range in which the blade moves can be limited. Although the torque in the low-speed rotation mode is slightly reduced by restricting the movement of the blade, the low-speed rotation mode is transient, and the side effect of slightly slowing down the acceleration is not a major problem. The windmill efficiency in the rotation mode is important.

In the present invention, the power transmission means for connecting the weather vane and the blade is not limited to a combination of a gear and a belt as in the above-described embodiment. Other forms may be used as long as they have the same function. FIG. 9 shows an example of a combination of three gears.

The number of blades of the vertical axis wind turbine according to the present invention is:
In the minimum case, it operates even with one sheet. However,
Since a single-blade windmill has poor symmetry, it is necessary to balance by adding a weight to the opposite side of the blade in order to avoid unnecessary vibration and distortion due to rotation. This problem can be avoided by a wind turbine in which a plurality of blades are arranged in a symmetric position, but torque fluctuation is still large in a wind turbine having two blades as shown in FIGS. In this regard, it is more preferable to use a wind turbine using three or four blades, which greatly reduces torque fluctuation.

[0022]

The vertical axis wind turbine of the present invention does not require any other wind turbine or starting means, and starts rotating only by wind power alone, smoothly accelerates to high speed rotation, and has a high wind turbine efficiency. Works as

[Brief description of the drawings]

FIG. 1 is a perspective view of an example of a vertical axis wind turbine according to the present invention.

FIG. 2 is a plan view of the vertical axis wind turbine of FIG. 1 as viewed from above.

FIG. 3 is an enlarged view around a blade and a weather vane.

FIG. 4 is a diagram illustrating a wind direction of a wind hitting a blade and a force acting on a windmill. Wind speed vectors are indicated by outline arrows, and force vectors are indicated by black arrows.

FIG. 5 is a diagram illustrating an operation in a low-speed rotation mode. Wind speed vectors are indicated by outline arrows, and force vectors are indicated by black arrows.

FIG. 6 is a diagram illustrating an operation in a high-speed rotation mode. Wind speed vectors are indicated by outline arrows, and force vectors are indicated by black arrows.

FIG. 7 is a cross-sectional view of two different types of blades.

FIG. 8 is a diagram illustrating a modified portion for using an asymmetric blade 3s.

FIG. 9 is a diagram showing an example in which three gears are used as power transmission means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main axis (rotation axis) of windmill 2a, 2b ... Arm 3 ... Blade 3s ... Asymmetric blade 4 ... Weather vane 5 ... Weight to balance 6,12 ... Blade Gears fixed to 3 7 ... Blade shafts 8 and 13 ... Gears fixed to weather vane 4 9 ... Belt 10 ... Shafts of weather vane 4 11 ... Movement of weather vane 4 14 ... Gear d ... Rotation direction of windmill

Claims (1)

[Claims] 1. A vertical axis wind turbine having at least one or more blades, wherein the blades are installed at a predetermined distance from a main axis and rotatable about an axis parallel to the main axis, The axis of the blade is a weather vane installed adjacent to each blade, and a line connecting the main axis of the windmill and the blade, with the blade rotating by half the rotation angle of the wind vane by the power transmission means. A vertical axis windmill characterized in that when the weather vane is vertical, adjacent blades and the weather vane are connected to be vertical or parallel.