Two drag-type windmills having contact point on rotation track of blade and synchronizing blade rotation

Abstract

To provide a drag-type windmill that increases utilization efficiency of wind force.SOLUTION: A drag-type windmill comprises a blade freely rotatable around a rotational axis perpendicular to a wind direction. Front and back sides in a rotational direction of the blade assume a shape in which drags generated by a wind are different from each other. The two drag-type windmills are provided. Rotation tracks of both the blades have a contact point. Rotations of both the blades are synchronized with each other so that both the blades can be rotated upwind in a position of the contact point and so that the one blade can be located to leeward of the other blade.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drag wind turbine. [Background technology]

[0002] Conventional drag-type wind turbines rotate around an axis perpendicular to the wind direction, and receive wind on both the blades that face downwind and the blades that face upwind against the wind. The difference in drag caused by the difference in the shape of the front and back surfaces of the blades in the direction of rotation is used as output torque, which limits the efficiency of wind power utilization. Summary of the Invention [Problem to be solved by the invention]

[0003] To provide a drag-type wind turbine with improved wind power utilization efficiency. [Means for solving the problem]

[0004] To achieve the above object, two drag-type wind turbines have blades that can rotate freely around a rotation axis that is perpendicular to the wind direction, and the front and back surfaces of the blades in the direction of rotation have shapes that create different drag forces due to the wind. In this drag-type wind turbine, there are two such drag-type wind turbines, and the rotational orbits of both blades have a contact point, and at the point of contact both blades rotate upwind and one blade is located downwind of the other, so the rotation of both blades is synchronized. [Effects of the Invention]

[0005] When the blades of the two drag-type wind turbines rotate upwind, they overlap in the front-to-back direction of the wind direction, so the area of ​​the blades facing upwind, which receives the wind and generates rotational torque, is reduced to about half that of conventional devices, providing a drag-type wind turbine with improved wind power utilization efficiency. [Brief explanation of the drawings]

[0006] [Figure 1]Principle diagram [Figure 2] An example of combining multiple wedge-shaped devices in which the rotating blades split the wind into upper and lower sections. DETAILED DESCRIPTION OF THE INVENTION

[0007] A feather is a surface-like object that interacts with the wind. A drag-type wind turbine is a wind turbine that receives wind on blades that can rotate freely around an axis of rotation perpendicular to the wind direction, and outputs the difference in drag caused by the difference in the shape of the front and back sides of the blades in the direction of rotation as rotational torque.

[0008] The rotational orbits of both blades have a point of contact with each other means that the rotational orbits of at least one point on the surface of each blade of the two drag-type wind turbines around the rotation axis have a point of contact with each other. At the point of contact, most of the rotational trajectories of the surfaces of both wings intersect, causing one wing to be downwind of the other. However, this does not mean that the entire cross section of the rotational trajectories of the surfaces of both wings intersect; rather, the rotational trajectories of many points on the surfaces of both wings are in contact with each other; this is strictly defined as the rotational trajectories of at least one point on the surfaces of both wings being in contact with each other.

[0009] Unlike ordinary drag-type wind turbines, this configuration has directionality, so it must always be pointed upwind, just like a horizontal axis wind turbine. In the figure, the pointing axis rotates together with the arrow blades that rotate downwind due to wind force, and this is achieved by a mechanism that aligns the inclination of the gimbal with the wind direction at its diagonal cut surface, but it is also possible to use a pointing axis that holds the rotating shafts of two drag-type wind turbines that are tilted relatively to the wind direction and rotates toward the wind direction, and the present invention is not limited to these mechanisms, and since this is existing technology, details will be omitted. Incidentally, excessive rotation can be prevented by intentionally moving the direction of the pointing axis away from the wind direction. As another embodiment of directionality, taking the hemispherical wing shape of Figure 1 as an example, if the hemisphere is further divided into two halves, top and bottom, to form a quarter sphere, and a windmill with the wing shape of the upper half is placed on top and a windmill with the wing shape of the lower half is placed on the bottom, a force will be generated in the upwind position for the upper half of the wing to be downwards and in the lower half for the wing to be upwards, causing the wing to overlap, and in the downwind position the opposite force will be generated, causing the wing to separate, making it possible to create an omnidirectional device. The shape of the blade surfaces of the two drag-type wind turbines is preferably a fan shape of about 45 degrees due to the inclination angle. It is also possible to have two or more drag-type wind turbine blades with contact points on their rotational orbits. Although less efficient, it is also possible to use two parallel rotating shafts that rotate in opposite directions.

[0010] The structure in which the rotation of both blades is synchronized so that one blade is located downwind of the other can be realized by a structure in which the rotation of the rotating shafts of the two drag-type wind turbines that hold each blade is synchronized. In the figure, the blades of the two drag-type wind turbines are connected to the same output rotating shaft by a gimbal similar to a universal joint that can transmit rotation even when the angle changes, and the inclined surface of the gimbal is configured to face the wind direction, but any structure that can synchronize the rotation of the rotating shafts of the two drag-type wind turbines while maintaining the relative angle of the rotating shafts of the two wind turbines, such as a structure in which gears on each of the rotating shafts that are inclined relative to each other, is sufficient; the mechanism is not limited to these. Furthermore, friction associated with mechanical mechanisms creates a rotational load and makes it difficult to start from no wind, so a mechanism that minimizes the rotational load as much as possible, such as using the attraction and repulsion of magnets, is desirable, but these are all existing technologies and details will be omitted.

[0011] To explain the principle, Figure 1 shows a typical drag-type wind turbine as a paddle-type turbine with the surface of the blade facing the direction of rotation being hemispherical, but the shape of the blade is not limited to this shape, as with general drag-type wind turbines, as long as the surface facing the direction of rotation has less wind resistance than the surface facing the opposite direction of rotation. Furthermore, since the blades on the lee side of the other wind turbine blades have less wind resistance, the efficiency remains the same even if they have a shape closer to a flat plate, and in fact the resistance can be reduced by moving closer to the blades on the upwind side. Unlike conventional drag-type wind turbines, this configuration does not allow for the area of ​​the blades to be increased by widening the width of the blades in the direction of the rotation axis. Therefore, in one embodiment, this configuration is placed above and below as shown in Figure 2, and the upper and lower wind turbines rotate in opposite directions to increase the area of ​​the blades. It is desirable to design the shape of the blades so that there is little space between the upper and lower blades, and the remaining space can be reduced by making the rotation axis in that area thicker, and the wind in that area can be guided to the blades. Furthermore, as shown in Figure 2, if the convex surface of the blade facing the direction of rotation is shaped like a wedge that allows wind to escape up and down, the wedge-shaped surface of the blade rotating toward the wind will split the wind into upper and lower parts, and the blades rotating toward the downwind side of the counter-rotating wind turbines placed above and below will receive the wind, further improving the efficiency of wind utilization. Efficiency can be further increased by synchronizing the rotation of the wind turbines placed above and below each other. If the outer circumferential edge of the wedge-shaped blade surface is inclined outward rather than up and down, rotational torque can be obtained by the Coanda effect at the position where the blade receives wind from the outer circumferential edge direction. If the blade surface is extended on the opposite side of the axis of rotation, a Savonius effect can be achieved. The number of blades must be at least two, positioned symmetrically about the axis of rotation, but may be more than that. Although this configuration is called a windmill, it can also be implemented as a watermill. [Explanation of symbols]

[0012] 1 pedestal 2 Output rotating shaft 3 Directional axis 4 Directional Fletching 5 birds 6. Gimbal

Claims

[Claim 1] In a drag-type wind turbine, which has blades that can rotate freely around a rotation axis perpendicular to the wind direction, and the front and back surfaces of the blades in the rotation direction have a shape that generates different drag due to the wind, The two drag type wind turbines are provided with two such drag type wind turbines, and the rotational orbits of both blades have a point of contact, and at the point of contact both blades rotate upwind and the rotation of both blades is synchronized so that one blade is located downwind of the other blade.

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