JP2016017463A - Vertical axis wind turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical axis wind turbine having an overspeed prevention structure including a quite simple structure without using any surplus control parts so as to restrict only an axial motion of a blade shaft supporting a blade and a self-rotation of the blade shaft and enabling its manufacturing to be attained in less-expensive manner.SOLUTION: In this invention, one end part of a blade shaft 21 is held at a rotary hub and a blade is fixed to the other end of the blade shaft 21. This blade shaft 21 can be moved in a radial direction due to a centrifugal force accompanied by rotation of the blade and at the same time the blade shaft is twisted around an axis of its radiation direction to cause a wind receiving area of the blade and an effective pitch angle of the blade to be changed and there is provided a restricting structure for restricting a motion of the blade shaft in its radial direction and its self-rotation.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vertical axis wind turbine used for a wind power generator. More specifically, the present invention relates to a vertical axis wind turbine provided with an over-rotation control mechanism that prevents a generator from being damaged due to over-rotation even when a strong wind due to a gust of wind blows.

  The small windmill is useful as a distributed power source because it is useful as a power source in a place where there is no system power source or an emergency power source when the system power source is interrupted in the event of a disaster. However, safety considerations are important because high-speed rotation easily occurs in strong winds, and the cost tends to be high, and it is not widespread. Many recent small wind turbines use electric brakes to reduce the number of rotations at high speeds, but there is a high possibility that an electric circuit will fail during strong winds, and the maximum current of the generator Due to the limitation, the maximum wind speed is about 12 to 14 m / s. Many methods have been proposed for mechanically suppressing the number of rotations when a strong wind blows, but there are many methods with complicated mechanisms and problems with reliability, and they have not been fully put into practical use. However, in general, if the pitch angle of the blade can be passively controlled as the rotation speed increases, the number of rotations can be suppressed even in a strong wind state, and safety is improved. In addition, since the wind speed range in which the wind turbine can be operated is expanded, the capacity of the generator can be reduced, so that the unit price of power generation can be reduced.

  Horizontal wind turbines are the mainstream for large wind turbines, but in the case of small wind turbines, the installation location is often close to the ground surface and the wind direction is disturbed, so there is no dependency on the wind direction (the yaw control mechanism is Unnecessary), vertical axis wind turbines (or vertical axis wind turbines), which can be simple in structure, are often used. Many small vertical axis wind turbines have a fixed pitch system. For example, Patent Document 1 discloses a centrifugal force acting on the whole or a part of a linear blade (both ends are inclined) installed at a position away from the rotation center axis. Has proposed a mechanism to change the pitch angle by passively swinging the blades using the. Also in Patent Document 2, a mechanism for changing the pitch of a blade of a straight blade vertical axis wind turbine by utilizing centrifugal force or the like is proposed. In any method, movable parts such as hinges and elastic bodies such as springs are arranged at a position away from the rotation center axis, and it is necessary to devise in processing such as incorporating these movable parts inside the blade. Yes, in some cases the cost can be high. Also, if they are installed outside the blades, there is a possibility of reducing the efficiency of the windmill because of increased aerodynamic resistance. In the pitch variable mechanism, it is necessary to synchronize the change in the pitch angle of the blades in order to achieve stable windmill rotation. Therefore, it is necessary to use a long link mechanism for synchronizing them, and it is expected that it is difficult to ensure the reliability in long-term operation.

  On the other hand, in a small horizontal axis wind turbine, it is possible to incorporate a mechanical over-rotation control mechanism in the vicinity of the rotation shaft. For example, the helical feathering method shown in FIG. It is. The basis of FIG. 1 of Patent Document 3 is introduced on page 146 of Non-Patent Document 1 together with other methods such as a method using a governor weight and a wind pressure method (sliding hub method). The helical feathering method uses centrifugal force acting on the blade, and the blade moves (slides) in the direction of the centrifugal force (radial direction) and rotates (spins) around the support shaft that supports the blade to increase the pitch angle. As a changing mechanism, a helical (helical) guide groove is used. However, when a plurality of blades are provided, there is no tuning mechanism for making the length from the center of rotation to the center of gravity of each blade the same. Patent Document 3 proposes a pitch variable mechanism and a tuning mechanism using a special hinge joint in order to solve the instability due to sliding in the guide groove, which is a drawback of the helical feathering method. However, it is considered that it is difficult to study the strength in practice. Many proposed methods using governor weights use gears, tuning mechanisms using hinges and links, etc., but the mechanism is already complicated in terms of adding weights. The above-described variable pitch overrotation control mechanism for a horizontal axis wind turbine is desirable in that the mechanism can be disposed near the rotation axis, but the gravity acting on the blade acts in a direction perpendicular to the horizontal wind turbine rotation axis. As the blade rotates, the radial force applied to the blade periodically changes. Therefore, a tuning mechanism is essential for stable operation. In addition, since the method described above only changes the pitch angle of the blade and does not change the wind receiving area, even if a constant rotation speed is obtained during strong wind as a result of over-rotation control, it is the same as in the low rotation speed state. The wind turbine as a whole must be strong enough to withstand the large thrust acting on the area.

  Various types of wind turbine blade structures have been proposed. For example, an H-type Darius wind turbine having a general straight blade and a butterfly type non-linear blade are also known. Furthermore, the blade of the “aluminum circular blade butterfly windmill” manufactured by extrusion and bending of an aluminum alloy as prototyped in Non-Patent Document 2 is superior in terms of cost and structural strength.

JP 2010-127072 A JP 2007-85182 A Japanese Patent Laid-Open No. 2007-9898

Small windmill handbook, Ushiyama Izumi and Mino Masahiro, Power, 4th edition, 1994 Demonstration experiment and performance prediction of aluminum circular wing butterfly wind turbine, Journal of Japan Wind Energy Association, Vol.38, No.1, (Vol.109), (May 2014)

  As described above, in the vertical axis wind turbine, various means have been proposed for controlling the rotation speed of the blade by utilizing the property that the centrifugal force increases as the rotation speed of the blade increases, thereby suppressing over-rotation.

  However, in the examples shown in Patent Documents 1 and 2, since the mechanism is a mechanism for rotating the blade or a part thereof with respect to the blade shaft that supports the blade, the manufacturing is complicated and expensive, and the blade is easily damaged. There is a problem.

  Patent Document 3 and Non-Patent Document 1 are examples of suppression of over-rotation with respect to a horizontal axis wind turbine. In this case, the angle formed between the direction of the wind and the direction of the blade is reduced in a strong wind by restricting the support shaft that supports the blade by the spiral groove so as to rotate. However, in the case of a horizontal axis wind turbine, the blade's own weight acts in the direction perpendicular to the rotation axis, so the volume force (centrifugal force + blade's own weight) acting in the radial direction of rotation changes with the rotation direction, There is an imbalance. On the other hand, when this is applied to a vertical axis wind turbine, the blade's own weight acts in a direction parallel to the rotational axis, so the volume force acting in the rotational radius direction is only the centrifugal force, and the rotation occurs when the rotational speed is constant. Regardless of the direction, the radial body force is essentially constant. However, there has been no report on an example in which the methods described in Patent Document 3 and Non-Patent Document 1 are applied to a vertical axis wind turbine. Further, in this configuration, since only the spiral groove is provided, the angle between the direction of the blade and the direction of the wind is reduced simultaneously with the action of the centrifugal force. As a result, there is a problem that even if the wind force is small, the angle between the blade direction and the wind direction becomes small, and the wind force cannot be used effectively. Furthermore, in the structure in which the support shaft of the blade is moved in the direction of the centrifugal force by the centrifugal force in this way, in particular, if the length from the rotation center to the center of gravity of the blade is not the same length among the plurality of blades, However, there is no disclosure of a tuning mechanism for making the length from the center of rotation to the center of gravity of the blade constant among a plurality of blades.

  The present invention has been made in view of such circumstances, and has a very simple structure that only restricts the axial movement of the blade shaft that supports the blade and the rotation of the blade shaft without using extra control components. An object of the present invention is to provide a vertical axis wind turbine having an over-rotation prevention structure that can be manufactured at low cost.

  Another object of the present invention is that when a single windmill has a plurality of blades, the length from the rotation center of each blade to the center of gravity of the blade is not limited even if the blade shaft is regulated by centrifugal force for each blade. Vertically equipped with a tuning mechanism that keeps the movement amount of each blade axis constant so as not to harm the stabilization of the performance as a windmill or reduce the life due to the unbalance of the force received by each blade It is to provide an axial windmill.

  The vertical axis wind turbine according to the present invention includes a rotating hub, a blade shaft that is supported at one end by the rotating hub so as to extend in a radial direction from a rotation center of the rotating hub, and the other end of the blade shaft. A vertical axis wind turbine having a blade attached to the blade, wherein the blade shaft can move in the radial direction by a centrifugal force accompanying the rotation of the blade, and rotates around the radial direction as an axis. A regulation structure is provided so that the effective pitch angle (mounting angle) and the wind receiving area can be changed, and the radial movement and the rotation of the blade shaft are regulated.

  Here, the effective pitch angle (mounting angle) refers to the blade chord length line (relative to the blade cross section) relative to the relative wind in each cross section of the blade mounted on the blade shaft, which varies according to the rotation angle (twist angle) of the blade shaft. This means the set angle of the straight line connecting the edge and the trailing edge.

  Until the blade reaches a predetermined centrifugal force, the blade shaft moves in the radial direction so that the wind receiving area of the blade is maintained at a predetermined area or more, and the blade is centrifuged at the predetermined centrifugal force or more. If the force becomes a force, the blade shaft rotates with the radial movement, the wind receiving area is reduced, and the restriction structure is formed so as to increase the effective pitch angle. Accordingly, it is preferable because wind energy can be used effectively.

  Here, the predetermined area is an area within a range in which a wind receiving area comparable to the maximum wind receiving area is maintained, and refers to an area within a range in which the rotation speed of the blade is maintained. The predetermined area is, for example, in the range of 95 to 100% of the maximum wind receiving area, and more preferably in the range of 98 to 100%.

  The blade shaft moves only in the radial direction until the blade has a predetermined centrifugal force. When the blade has a centrifugal force equal to or greater than the predetermined centrifugal force, the blade shaft rotates with the radial movement. Thus, it is preferable that the regulation structure is formed because wind energy can be effectively used according to the strength of the wind.

  In this specification, the phrase “the blade axis moves only in the radial direction” is used in contrast to the term “spins along with the movement in the radial direction”, and the blade axis is substantially in the radial direction. The part which moves only to the extent that the blade shaft rotates slightly in a range where the rotational speed of the windmill hardly decreases to a predetermined centrifugal force is included. Further, in the embodiment described later, the portion that moves only in the radial direction is shown as a straight portion, but is not limited to a straight portion, and the object of the present invention is, for example, a gently curved portion. You may have another structure in the range which can be achieved.

  The regulating structure guides the movement of the blade shaft in the radial direction and the rotation of the blade shaft, and a guide portion provided on one of the blade shaft and the periphery of the blade shaft; and By providing the blade shaft and an engagement portion that is provided on the other periphery of the blade shaft and engages with the guide portion, the regulation structure can be configured with a simple configuration.

  Of the guide portion, the portion where the blade shaft moves only in the radial direction is a linear portion along the radial direction, and the portion where the blade shaft both moves and rotates in the radial direction is: A rotational speed formed by a spiral part formed continuously with the linear part, and the length of the linear part along the radial direction corresponds to the rated rotational speed of the generator of the vertical axis wind turbine. When the blade rotates, the blade shaft is 30 to 80% of the distance that the blade shaft slides in the radial direction due to the centrifugal force acting on the blade. When the wind speed is low, the blade shaft is twisted. If the wind speed increases while using wind power flowing into the maximum wind receiving area, the twist angle is increased to reduce the wind receiving area to reduce the wind power and the effective pitch angle (mounting angle) It is possible to suppress excessive rotation of the blade by increasing to allowed to reach a stall condition.

  A plurality of blade shafts having the blades are attached to the rotation hub, and a tuning mechanism is provided so that the rotation angles of the blade shafts by rotation are equal. On the other hand, it is preferable because unbalance of the blades due to different rotation radii can be prevented and failure can be prevented in advance.

  A universal joint is connected to one end of the blade shaft, and the tuning mechanism includes a tuning disk provided coaxially with the rotation center of the rotation hub and rotated independently with respect to the rotation hub, A first hinge formed on the tuning disk at a certain radius from the center of the tuning disk and the universal joint may be connected to each other by a link having a certain length.

  A link connecting between the universal joint and the first hinge formed on the tuning disk includes a first link extending in a vertical direction from the universal joint, and a first link at a distal end portion of the first link. A large link with respect to a short movement in the radial direction of the blade shaft by being formed by a second link extending horizontally between the first hinge on the tuning disk via two hinges Since the change in angle can be allowed, it can be formed compact without taking up space.

  According to the present invention, when the wind force increases and the rotation speed of the blade increases while moving the blade shaft in the axial direction by using the centrifugal force received by the blade, the blade rotates together with the blade shaft. When the effective pitch angle (mounting angle) is increased and the wind receiving area is decreased, and the wind force is not so large, even if the blade shaft moves in the axial direction, the blade shaft itself does not rotate ( Do not twist). Therefore, when the wind force is small, even if the blade shaft moves in the axial direction of the blade shaft due to centrifugal force, the blade tilts and the effective pitch angle (mounting angle) increases and a part of the blade is stalled. In addition, the wind force flowing into the maximum wind receiving area can be efficiently used without reducing the wind receiving area. That is, with respect to an increase in the rotation speed of the blade until the rotation speed becomes close to the excessive rotation speed, it is possible to receive the wind flowing into the maximum wind receiving area and efficiently rotate the windmill to generate power. On the other hand, when a constant centrifugal force close to over-rotation is generated, the blade shaft can be rotated by, for example, a restricting structure of the blade shaft and a cover provided around the blade shaft. Therefore, the effective pitch angle (mounting angle) increases, a part of the blade is stalled, and the wind receiving area is also reduced. As a result, the number of rotations of the blade is not increased and the centrifugal force is not increased. Therefore, even in the case of a strong wind that causes the conventional windmill to over-rotate, a stable blade rotation speed can be obtained before the over-rotation.

  In other words, until the predetermined wind force, the blade shaft moves only in the axial direction, receives the wind force flowing into the maximum wind receiving area, and the wind force becomes stronger than the predetermined wind force, and the situation becomes a conventional overspeed. When the blade is tilted, the effective pitch angle (mounting angle) is increased, and a part of the blade is stalled. In addition, when the wind force becomes even stronger, the blade inclination (twist) becomes even larger, and in the extreme case, the blade tilts 90 degrees (twist), so that no matter how strong the wind is, the wind force is hardly received. , Stable rotation of the blade can be maintained in front of it.

  If a restricting structure including a guide portion and an engagement portion as shown in claim 4 is adopted, it is only necessary to adjust the moving length of the guide portion only in the axial direction of the blade shaft. It is applicable also to the generator which has such a power generation capability. As a result, an optimal wind power generator can be manufactured at a low cost according to the installation location or the strength of the wind depending on the topography. That is, when the output of the generator is increased, the cost increases rapidly. However, as shown in Non-Patent Document 2, for example, the blade can be manufactured at a very low cost when formed by extrusion of aluminum or the like. In places where the wind is not so strong, it is possible to efficiently generate power using a wind turbine having a large radius with a generator having a small power generation capacity. Moreover, by installing many generators with such a small power generation capability, the total power generation cost can be reduced. On the other hand, in places with a lot of strong winds, it is efficient to generate electricity using as much wind as possible using a generator with high power generation capacity. In any case, by combining the movement of the blade shaft only in the axial direction and the rotation of the blade shaft of the present invention, over-rotation can be prevented without impairing the power generation capacity.

  In addition, by providing a tuning mechanism, there is a variation in aerodynamic force (area force) acting on the blade surface depending on the rotational azimuth angle of the windmill, and aerodynamic imbalance based on manufacturing errors of members used in the windmill. However, the movement amount of the blade shaft in the axial direction and the inclination angle (twist angle) of the blade are synchronized. That is, even if one of the plurality of blades receives a strong aerodynamic force to incline the blade, it does not change unless the other blades receive such a strong aerodynamic force, and the overall centrifugal force does not change. In addition, there is no unbalanced movement by the blade. As a result, stable rotation can be obtained.

It is explanatory drawing of the overspeed control part of one Embodiment of this invention. In the plan view of an embodiment of the wind turbine according to the present invention, only a mounting portion for four blades is shown, and one blade shaft has no twist by removing the surrounding cover (guide portion). It is a figure which shows the case where it twists about 37 degree | times. It is the perspective view seen from the front side when the blade of the windmill of FIG. 2 is made into one sheet. It is a figure explaining the wind-receiving area of the windmill of FIG. It is a figure explaining an effective pitch angle. It is a figure which shows the relationship of the effective pitch angle with respect to a twist angle. It is a figure which shows the relationship of the blade rotation speed with respect to the wind speed of the windmill shown by FIGS. 1-4, and the relationship of the centrifugal force, the twist angle, and the blade axis | shaft movement amount with respect to the rotation speed. It is a top view of the blade part of the windmill shown by FIGS. It is an illustration of the blade shape used for this invention. This is the shape when the twist angle when using a butterfly blade is changed. It is the same front and plane explanatory drawing as FIG. It is a figure which shows the relationship of the rotation speed with respect to the wind speed and twist angle of the windmill formed by this invention (however, the linear movement part in which a twist angle becomes 0 degree is not included). It is a figure which shows the rotation speed dependence of a twist angle and a wind receiving area. It is a figure which shows the electric power generation characteristic [cutout: 15m / s] of a windmill (diameter: 3.1m) without an overspeed control mechanism. It is a figure which shows the electric power generation characteristic [cutout: 70 m / s or more] of a windmill (diameter: 3.1 m) with an overspeed control mechanism. It is a figure which shows the comparison of the power curve with the case where there is overspeed control and there is no. It is a figure which predicts annual electric power generation amount on the assumption that a wind speed appearance rate follows Rayleigh distribution.

  An embodiment of a vertical axis wind turbine according to the present invention will be described with reference to the drawings. The vertical axis wind turbine according to the present invention has a rotation center (axis C) of the rotation hub 11 (see FIGS. 2 to 3), as shown in FIG. One end portion side of the blade shaft 21 is held on the rotating hub 11 so as to extend in the radial direction from the blade shaft 21, and a blade 22 (see FIG. 3) is attached to the other end portion of the blade shaft 21. In the present invention, the blade shaft 21 can move in the radial direction of the rotating hub 11 due to the centrifugal force associated with the rotation of the blade 22, and rotates (twists) around the radial direction as an axis to receive wind from the blade 22. It is attached so that the area and the effective pitch angle can be changed. That is, the vertical axis wind turbine of the present invention is provided with a restriction structure that restricts the movement and rotation of the blade shaft 21 in the radial direction of the rotating hub 11, and the movement of the blade shaft 21 in the radial direction by this restriction structure. And rotation (twist) is regulated. In the example shown in FIG. 1, the blade shaft 21 moves only in the radial direction until the blade 22 has a predetermined centrifugal force, and when the blade 22 has a centrifugal force equal to or greater than the predetermined centrifugal force, the blade shaft 21 has a radius. The restricting structure is formed so as to rotate along with the movement of the direction. In the present specification, the “radial direction” means a direction away from the rotation center of the rotation hub 11 or a direction approaching the rotation center on the rotation surface of the rotation hub 11.

  The entire configuration of the wind turbine according to the present invention is the portion of the rotating hub 11 formed so that the four blades 22 are attached in FIG. 2 (the blade 22 is omitted and only the blade attachment portion 22a is shown). FIG. 3 is a plan explanatory view, and FIG. 3 is a perspective explanatory view in which one blade 22 is provided. Each blade shaft 21 does not rotate (twist angle is 0), and the blade shaft 21 rotates about 37 degrees (hereinafter referred to as “rotation angle”). The rotation hub 11 is fixed to the generator 31 and the blades 22 are attached to the rotation hub 11 via an appropriate number of blade shafts 21 as shown in the state of a twist angle of 37 degrees). Yes. When the blade 22 receives wind and rotates, the rotating hub 11 is rotated, whereby the central axis of the generator 31 rotates to generate power.

  In the example shown here, two frames 12 fixed to the rotating hub 11 (in FIG. 1, the rotating hub 11 is omitted, but the lower side of the two frames 12 is the rotating hub. The blade shaft 21 is held in the through-hole 12a (fixed to the blade 11) so as to slide in the radial direction of the rotating hub 11 and rotate (spin) around the radial direction. When the wind 22 receives wind, the rotating hub 11 itself rotates about the axis C.

  Further, the regulation structure described above guides the movement of the blade shaft 21 in the radial direction and the rotation of the blade shaft 21, and a guide portion provided around one of the blade shaft 21 and the blade shaft 21. And an engagement portion that is provided on the other side of the blade shaft 21 and around the blade shaft 21 and engages with the guide portion. The periphery of the blade shaft 21 here is not limited to the one that completely covers the periphery of the blade shaft 21, and may be at least a part in the circumferential direction and the axial direction around the blade shaft 21. In the present embodiment, the guide portion is provided between the two frames 12 around the blade shaft 21, for example, a cover 13 formed in a cylindrical shape (indicated by a two-dot chain line in FIG. 1). The guide groove 13a formed in FIG. 1 (only the outer shape is shown by a two-dot chain line in FIG. 1, the guide groove 13a is shown in a plan view projected, and in FIGS. The engagement portion is shown as a pin 24 that protrudes outward from the outer periphery of the blade shaft 21 and engages with the guide groove 13 a of the cover 13. .

  The restricting structure is configured such that the guide shaft and the engaging portion engage with each other, and the blade shaft 21 moves in the radial direction and rotates by the centrifugal force accompanying the rotation of the blade 22. Thus, the structure is not limited to the embodiment shown in FIG. Therefore, for example, a structure in which the guide groove is provided on the blade shaft 21 side and the pin is provided on the inner surface of the cover 13 may be used, and even if the guide groove and the pin are not fitted, for example, the protrusions are in contact with each other. Various structures such as a shift structure can be employed. In the example shown in FIG. 1, a flange portion 23 is formed on the blade shaft 21, and a pin 24 is formed on the outer peripheral surface of the flange portion 23. In the present embodiment, the cover 13 fixed to the rotating hub 11 is provided so as to cover at least a part of the blade shaft 21, but the cover 13 is optional in the present invention. Any structure other than the cover 13 may be used as long as it has a guide part or an engaging part.

  In the example shown in FIG. 1, an elastic body 25 such as a spring member is interposed so as to wind the blade shaft 21 between the flange portion 23 and one frame 12. The aforementioned cover 13 is provided, for example, as a cylindrical tube so as to cover the periphery of the elastic body 25, and the aforementioned guide groove 13 a is formed in the cover 13. In the example shown in FIG. 1, a thrust bearing 26 is inserted between the other end of the elastic body 25 and the frame 12. The elastic body 25 has a centrifugal force that increases due to the rapid rotation around the rotation center (axis C) of the blade 22, and the blade shaft 21 slides in the radial direction of the rotating hub 11, and then the wind force weakens and the blade 22 This is for automatically returning the blade shaft 21 to the original state when the rotational force is reduced. Therefore, the elastic body 25 does not need to be formed by a compression spring, as shown in FIG. 1, and may be an elastic body such as a simple columnar rubber that has been hollowed out at the center. Other types such as a tension spring that pulls from one end of the blade shaft 21 may be used. In short, the elasticity of the blade shaft 21 that has been slid in the radial direction by a large centrifugal force is restored when the large centrifugal force is eliminated. Any body is acceptable. Since the elastic body 25 is inserted, the sliding of the blade shaft 21 in the radial direction is governed by the magnitude relationship between the centrifugal force F and the restoring force Q of the elastic body 25. That is, in a state where the centrifugal force F is larger than the restoring force Q of the elastic body 25 (FQ> 0), the blade shaft 21 slides in the radial direction so that the distance from the rotation center (axis C) increases. Conversely, when the centrifugal force F is smaller than the restoring force Q of the elastic body 25 (FQ <0), the blade shaft 21 slides in the radial direction so that the distance from the rotation center (axis C) becomes small. Thus, when the centrifugal force F and the restoring force Q of the elastic body 25 are in the same state (F = Q), the movement in the radial direction stops.

  In the present invention, the movement of the blade shaft 21 due to this restricting structure is depicted as a straight line portion 13a1 and a spiral portion 13a2 of the guide groove 13a (in FIG. 1, which is depicted as an oblique straight line, but in a projection view). Therefore, the guide groove 13a is actually formed in the cylindrical cover 13 so as to rotate in the circumferential direction and also advance in the axial direction, so that it is a spiral guide groove). There is a feature. When the blade 22 rotates fast with strong wind power, the pin 24 fitted to the linear portion 13a1 also increases the centrifugal force received by the blade 22, and the blade shaft 21 slides in the radial direction of the rotating hub 11 by the centrifugal force. Have been guided. Then, the centrifugal force F becomes larger than a certain centrifugal force (for example, in FIG. 6, about 4,500 N of the centrifugal force corresponding to the rotational speed of 190 rpm at a wind speed of 10 m / s), and the above-mentioned centrifugal force F is the restoring force Q of the elastic body 25. In a larger state (FQ> 0), the pin 24 advances into the guide groove 13a2 in the spiral portion, and the blade shaft 21 not only moves in the radial direction but also rotates (rotates) about the axis of the blade shaft 21. . When the blade shaft 21 rotates (twist), the wind receiving area by the blade 22 is reduced and the effective pitch angle is increased, and the rotational force generated by the blade 22 is weakened even when a strong wind is blown. As a result, the centrifugal force F and the restoring force Q of the elastic body 25 are balanced (F = Q), and an appropriate rotational speed is maintained according to the wind speed.

When the blade shaft 21 rotates (twists), the wind receiving area decreases, and the effective pitch angle increases accordingly. The reason why the rotational force is weakened when the blade shaft 21 is twisted will be described. First, as shown in FIG. 4A, a front view of a wind turbine having four blades 22 (viewed from the front of FIG. 3), the area surrounded by the blades 22 on both sides (parts indicated by dots) ) A ₀ is the wind receiving area (maximum state) when the twist angle is 0 degree. The wind receiving area is not limited to the four blades 22 but is defined by the projected area of the portion to be swept when the single blade rotates around the axis C, that is, the sweep area. Since the blade 22 is fixed to the blade shaft 21 with a structure as shown in FIG. 4, when the blade shaft 21 rotates (twist), for example, forward, the circular shape becomes elliptical when viewed from the front. FIG. 4B shows a front view of a similar windmill when the blade shaft 21 rotates about 37 degrees (twist angle 37 degrees). As apparent from FIG. 4B, when viewed from the front, the shape of the blade 22 changes from a circle to an ellipse, and the projected area when the windmill rotates correspondingly decreases, and the area is A. When the twist angle of the blade shaft 21 is η, the wind receiving area A is A = A ₀ cos η, and the wind receiving area A changes according to the twist angle η as shown in FIG.

  When the blade shaft 21 is twisted, the effective pitch angle θ is also changed, and the rotational force of the windmill is weakened. The effective pitch angle means a set angle of a blade chord length line (a straight line connecting the leading edge and the trailing edge of the blade section) with respect to relative wind in each section of the blade 22, and in the present invention, the blade 22 having a twist angle η is used. The blade chord length line in a certain cross section is defined as an angle formed by a straight line projected on a plane including the orbit circle drawn by rotating the section around the rotation center axis C and the tangent line of the orbit circle. For example, as shown in FIG. 5C, if the distance from the center of the blade shaft 21 to the cross section of the blade 22 is z, and the blade 22 is twisted by an angle η, the effective pitch angle θ is

Given in. On the other hand, when the effective pitch angle θ is increased, the reason why the rotational force is weakened is, for example, in FIGS. 5 (a) and 5 (b). As shown in FIG. 5A, when the inclination of the blade 22 is small and the effective pitch angle θ is small, the blade 22 receives almost no aerodynamic resistance from the wind. On the other hand, as shown in FIG. 5B, when the inclination of the blade 22 is increased and the effective pitch angle θ is increased, the wind flow is separated from the blade 22 and the aerodynamic resistance is increased. As a result, the rotational force of the windmill is weakened. As a result, when the blade 22 is twisted, the output (the number of rotations) is suppressed by both the reduction of the wind receiving area and the increase of the effective pitch angle θ. As shown in the above formula (1) of the effective pitch angle with respect to the twist angle, the effective pitch angle θ increases as the twist angle η increases, but z = 0.275 m, FIG. 5A shows a graph of the effective pitch angle formed when the cross section of the blade 22 at the position of r = 1.389 m (z / r = 0.2) is inclined by the twist angle η. ing.

On the other hand, when the wind speed increases, the force to rotate the blade 22 by receiving wind is generally the force that the blade 22 receives as shown by a curve (broken line) without control in FIG. Increases monotonously and the rotational peripheral speed v (m / s) increases (the rotational speed N (rpm) increases) (the rotational speed N and the rotational peripheral speed v have a proportional relationship: v = 2πrN / 60). Accordingly, the centrifugal force F becomes F = mv ² / r = π ² mrN based on the rotational peripheral speed v or the rotational speed N of the blade 22, the mass m of the blade 22, and the distance r from the center of rotation to the center of gravity of the blade. ^It is obtained from 2/900. Therefore, as shown in FIG. 6B, the value of the centrifugal force F is determined with respect to the rotational speed N (rpm) of the blade 22. Therefore, it is necessary to control the rotational speed so as not to exceed a certain value depending on the specification of the generator, but the control structure of the present invention, for example, the curve with the control (solid line) in FIG. Thus, the number of rotations can be controlled by centrifugal force. 6B shows not only the centrifugal force F with respect to the rotational speed N of the blade 22, but also an example of a change in the twist angle η due to the rotation of the blade shaft 21 due to the increase in the centrifugal force, and the blade shaft 21 at that time. A change example of the movement amount d in the radial direction is also shown.

  The present invention is characterized in that the movement of the blade shaft 21 by the above-described restricting structure using the centrifugal force F is controlled by a linear linear motion and a spiral motion. That is, in the present invention, when the strong wind is used effectively in a strong wind region, the blade shaft 21 is moved until a centrifugal force corresponding to the rotational speed N when the wind speed is about 10 to 12 m / s. Is restricted to a linear motion in the radial direction, and on the other hand, the wind speed is 5 in the case of a wind power generator that reduces the unit price of power generation in a low wind area or by effectively using the weak wind to increase the equipment utilization rate. The movement of the blade shaft 21 is restricted to a linear motion in the radial direction until a centrifugal force corresponding to the rotational speed N at about -7 m / s is reached. In other words, about 30 to 80%, preferably about 40 to 70% of the centrifugal force corresponding to the rated allowable rotational speed determined by the generator, in other words, the rotational speed corresponding to the rated rotational speed determined by the generator, for example. When the blade rotates by a number, the length a is 30 to 80%, preferably about 40 to 70% of the distance that the blade shaft slides in the radial direction due to the centrifugal force acting on the blade (see FIG. 1B). ) As a straight portion, the straight portion 13a1 of the guide groove 13a is formed so as to move only in the radial direction up to the distance, and when the centrifugal force becomes larger than that, the blade shaft 21 moves in addition to the axial movement. The pin 24 is rotated in the circumferential direction, that is, spirally guided to the guide groove 13a, so that the blade shaft 21 rotates around the blade shaft 21. There. In short, in the present invention, the length a of the linear portion 13a1 of the guide groove 13a that moves only in the axial direction is matched with the wind condition (expected average wind speed) of the place where the present invention is applied or the range of wind speeds that are effectively used. Adjust. When the centrifugal force F reaches a centrifugal force at a rotational speed corresponding to a predetermined wind speed determined for the above purpose, the guide groove 13a is in the circumferential direction of the blade shaft 21, that is, the guide groove 13a shown in FIG. By being formed so as to move also in the oblique groove 13a2 in the projected view, the wind force becomes strong, and when the force becomes larger than the predetermined centrifugal force, the blade shaft 21 is rotated (spinned) to receive the wind. It is formed so as to reduce the area and reduce the rotational force. When the blade shaft 21 rotates, the wind receiving area decreases, and as described above, the effective pitch angle increases and the rotational force decreases as described above.

  FIG. 1 shows the movement of the blade shaft 21 by the regulating structure that regulates the mutual relationship between the guide groove 13a of the cover 13 and the blade shaft 21 when the centrifugal force of the blade 22 gradually increases. Is shown. That is, FIG. 1A shows a state where the centrifugal force of the blade 22 is small and the blade shaft 21 hardly moves, that is, a state where the windmill is stopped or rotating at a slight speed. There is no state.

  Next, as the wind speed increases and the rotation of the wind turbine rotor becomes a medium speed rotation state, when the blade shaft 21 moves outward in the radial direction of the rotating hub 11 due to an increase in centrifugal force, 1 (b), the centrifugal force F increases, and the blade shaft 21 moves in the radial direction with respect to the central axis C of the rotating hub 11 (see FIG. 2) by the centrifugal force, that is, in the axial direction of the blade shaft 21. A state in which the blade shaft 21 is slid is shown. In this state, since the guide groove 13a formed in the cover 13 is the straight portion 13a1, the blade shaft 21 is restricted so as to move only in the axial direction and not in the circumferential direction of the blade shaft 21. . In other words, the pin 24 fitted into the guide groove 13a is restricted by the linear portion 13a1 of the guide groove 13a and moves only in the axial direction of the blade shaft 21. At this time, the elastic body 25 is compressed by the flange portion 23 fixed to the blade shaft 21. That is, the blade shaft 21 moves to a position where the restoring force Q and the centrifugal force F of the elastic body 25 are balanced (F = Q).

  Further, when the centrifugal force F is larger than the restoring force Q of the elastic body 25 (F> Q), as shown in FIG. 1C, the blade shaft is guided by the spiral portion 13a2 of the guide groove 13a. 21 is regulated so as to rotate (twist) with respect to the axis of the blade shaft 21. Therefore, the pin 24 moves along the spiral portion 13a2 of the guide groove 13a, whereby the blade shaft 21 slides in the axial direction while rotating around the axis. The rotation (twist) about the axis rotates the blade 22 or the arm attached to the blade shaft 21, and changes the twist angle η and the effective pitch angle θ of the blade 22. When there is a change in the twist angle η and the effective pitch angle θ, the elastic body 25 contracts in the axial direction and also rotates around the blade shaft 21. As described above, the thrust bearing 26 is inserted between the elastic body 25 and the frame 12. Even when the pin 24 moves along the spiral guide groove 13a2 as described above, the plurality of horizontal links 17 to be described later have a constant movement with respect to a constant movement of the blade shaft 21 coupled thereto. When the horizontal links 17 are connected by the tuning disk 19, the twist angles of all the blades 22 change by the same angle, and the balanced twist angle changes (resulting in effective pitch). The change in angle is also uniform). If the twist angle increases, the wind receiving area by the blade 22 decreases, and at the same time the effective pitch angle increases, the rotational force that rotates the blade 22 decreases as described above, and the rotation speed stops increasing. The centrifugal force F also stops increasing. As a result, even if the wind speed is high, the centrifugal force is suppressed, and the blade shaft 21 stops at a position balanced with the restoring force Q of the elastic body 25. The state in which the blade 22 rotates (twisted) is shown in FIGS. 2 to 4B with a twist angle of about 37 degrees.

  In the schematic diagram shown in FIG. 1, a tuning mechanism is further shown. In this tuning mechanism, when the length from the rotation center to the center of gravity of the blade 22 is, for example, four blades 22 with one windmill, the extension (movement) of each blade shaft 21 in the axial direction is the same. It means a mechanism to do so. That is, when there are a plurality of blades 22, the wind received by each blade 22 may differ depending on factors such as the position of each blade 22 with respect to the wind direction. In particular, in the case of a vertical axis wind turbine, compared to a horizontal axis wind turbine, the wind received between the blades is often different depending on the direction of the wind (for example, when one blade is located on the windward side, There is a blade located). In this way, the blade 22 that has received a strong wind momentarily increases its rotational force, acts to increase its rotational speed, and also increases the force in the centrifugal force direction (due to the aerodynamic force acting on the blade surface). However, it is tuned by the tuning mechanism so as to have a length from the rotation center of the other blade 22 to the center of gravity of the blade 22. This is because if the length from the center of rotation to the center of gravity of the blade 22 becomes longer, the force received by the entire wind turbine rotor becomes unbalanced, and the adverse effect on the generator increases.

  In the example shown in FIG. 1, one end side of the blade shaft 21 is rotatably held by a universal joint 14, and a vertical link 15 is fixed to the universal joint 14, and the vertical link 15 is connected via a hinge (link connecting portion) 16. The first hinge (link connection) provided on the tuning disk 19 provided at a fixed distance (same radius) from the center of the tuning disk 19 connected to the horizontal link 17 and held concentrically with the rotating hub 11. Part) 18. That is, the length to the second hinge 16 connected to the vertical link 15 of the horizontal link 17 is provided with the tuning disk 19 provided so as to be rotatable independently of the windmill rotor, with the windmill rotor rotation shaft 32 as the rotation center axis C. The vertical link 15 is not related to the position in the horizontal direction, and the vertical length to the universal joint 14 where one end of the blade shaft 21 is held is constant (the vertical link is always Keep vertical). Therefore, when the blade shaft 21 slides in the axial direction, the universal joint 14 also moves in the radial direction of the rotating hub 11, but the tuning disk 19 rotates and the second hinge 16 is always vertically above the universal joint. is there. The distance from the center of the tuning disk 19 to the first hinge 18 and the length of the horizontal link 17 are constant, and the angle between the straight line connecting the center of the tuning disk 19 and the first hinge 18 and the horizontal link 17 is It is uniquely determined by the rotation angle of the tuning disk 19. Accordingly, the horizontal distance between the rotation center axis C and the second hinge 16, that is, the horizontal distance between the rotation center axis C and the universal joint 14, and further the horizontal distance from the rotation center axis C to the center of gravity of the blade 22 is determined by the tuning disk 19. It is uniquely determined by the rotation angle.

  If there are a plurality of blades 22, the same number of similar mechanisms are prepared, and one end of these horizontal links 17 is coupled to the same tuning disk 19 so as to be rotationally symmetric with respect to the rotor rotation axis. In this case, even if there is a slight difference in the centrifugal force acting on each of the plurality of blade shafts 21, the rotation angle of the tuning disk 19 is common to the plurality of mechanisms, and thus differs among the plurality of blade shafts 21. The operation is limited, and the movement amounts of the plurality of blade shafts 21 are the same. Even when the blade shaft 21 rotates around the shaft, the universal joint 14 undergoes both radial movement and rotational movement at the same time as the blade shaft 21, but the side coupled to the horizontal link 17 is connected by the universal joint 14. Since the rotational movement is suppressed, the two different movements can be smoothly combined. As is apparent from FIGS. 2A and 2B, the movement of the horizontal link 17 occurs when the blade shaft 21 from which the cover 13 has been removed slides outward in the radial direction (FIG. 2A). The first hinge (link connecting portion) 18 with the tuning disk 19 is almost directly below the figure, whereas the first hinge (link connecting portion) 18 when the twist angle is about 37 degrees is the blade The position is drawn in the direction of the shaft 21. Moreover, it can be seen that all of the horizontal links 17 connected to the four blade shafts 21 have the same positional relationship and are synchronized.

  Next, further description will be made based on a specific structure. FIGS. 2 to 3 and FIG. 7 are respectively a diagram (a) of a low wind speed state (state without twist) and a high wind speed state (a twist angle of about 37 degrees) in an example in which a wind turbine is constituted by four blades 22. 2 (b), FIG. 2 is a perspective view of the vicinity of the rotating hub 11, FIG. 3 is a perspective view from the front side in which only one blade 22 is provided, and FIG. FIG. 2 to 3, reference numeral 22a denotes a blade mounting portion.

  FIG. 8 shows four types of blade shapes of a vertical axis wind turbine applicable to the over-rotation control mechanism with a tuning mechanism of the present invention. (A) is one in which a horizontal arm is attached in the vicinity of the center of the straight blade in the span direction, and is usually called an H-type Darrieus windmill. (B) is a case of a non-linear blade, and a plurality of arms are assumed. However, if the connecting portion with the blade shaft is integrated and can be connected to the blade shaft, the over-rotation control is performed. The mechanism becomes applicable. Of course, one structure may be used as long as the blade does not vibrate. Although (c) is a butterfly blade, in this case, since there is no arm, the blade may be directly coupled to the blade shaft with an appropriate connecting member. (D) is a special case of the butterfly blade, but the case where the outline of the blade is almost circular is equivalent to the case of the prototype of Non-Patent Document 2 described above. It is desirable to mount any blade (and the structure with an arm) so that the center of gravity is on the extension line of the blade shaft. Further, in any blade shape, the twist angle is generated, thereby reducing the wind receiving area and obtaining an output suppressing effect. In addition, in order to obtain an aerodynamic resistance increasing effect, the twist angle is 0 degree. In the state, when the portion having the blade-shaped cross section is horizontal, the aerodynamic resistance increases rapidly when the twist angle changes, so that a large over-rotation control effect is easily obtained. From this point of view, the circular butterfly blade (d) is considered optimal. Even when the arm section as shown in (a) or (b) is provided, if the cross section of the arm is a blade type, the resistance is low when the twist angle is 0 degree, and the twist angle is large. A large overspeed control effect can be expected.

  Examples of the actual shape of such a circular butterfly blade are shown in FIGS. That is, FIG. 9 is a perspective view when the four blades have twist angles η of 0 degrees, 15 degrees, 30 degrees, and 45 degrees, respectively, and FIG. 10 is a front view (left side) and a plan view ( In both figures, when (a) has a twist angle of 0 degree, (b) has a twist angle of 15 degrees, (c) has a twist angle of 30 degrees, and (d) has a twist angle of 45 degrees. The shape of the case.

  Next, assuming a 3.1m diameter vertical axis wind turbine equipped with four circular butterfly blades, a comparison of expected output characteristics with and without the over-rotation control mechanism with tuning mechanism of the present invention was made. The results will be described.

  The diameter of one circular blade of the windmill assumed here is 1.1 m, and the center of gravity of the blade is located about 1 m from the windmill rotation axis C. The material of the blade is not particularly limited as long as the structural strength can be secured, but here it is assumed that an aluminum alloy is used, and the weight of one blade is 11.5 kg. As shown in FIG. 1, the periphery of a part of the blade shaft 21 is covered with a cylindrical cover 13 (diameter 90 mm). Although the generator is not shown in FIG. 1, it is assumed that the rated output is 1320 W and the maximum rotational speed (rated rotational speed) is 270 rpm. The elastic body 25 that is an element of the over-rotation control mechanism is a compression coil spring having a spring constant of 300 N / mm. In this case, as shown in FIG. 6B, when the rotational speed reaches 270 rpm, the displacement of the coil spring becomes about 30 mm, and the shape of the guide groove 13a of the over-rotation control mechanism so that the twist angle thereby becomes about 37 degrees. It was. However, the length a of the straight portion 13a1 is 15 mm, and when the wind speed is about 10 m / s or less, the pin 24 is in the straight portion and the twist angle remains 0 degree. It is assumed that the pin 24 moves along the spiral guide groove 13a2 from around the wind speed exceeding 10 m / s, and a twist angle is generated to suppress output.

  As a result of carrying out a simulation using this regulating structure, the relationship between the rotational speed (rpm) of the blade 22 with respect to the wind speed and the rotational speed with respect to the twist angle η (°) is shown in FIGS. Even if the wind speed increases and approaches 70 m / s, the number of rotations does not increase, but is within the rating, and when the wind speed increases, there is no need to stop the generator.

FIG. 12 shows the rotational speed dependence of the twist angle η and the wind receiving area A of the wind turbine obtained based on the characteristic prediction. Up to a rotation speed of 190 rpm, the twist angle is maintained at 0 degree. When the rotation speed is higher than that, the twist angle increases in proportion to the rotation speed. On the other hand, the wind receiving area gradually decreases as the twist angle increases, and in the state where the rotation speed is 260 rpm, the wind receiving area is reduced by about 15% with respect to the original wind receiving area (A ₀ = 3.154 m ² ) (wind receiving area: A = 2.675 m ² ).

  FIG. 13 is a prediction of power generation characteristics when the overspeed control is not performed. It is predicted that the rated output 1320W of the generator will be reached at a wind speed slightly exceeding 14 m / s. It is assumed that the windmill without the over-rotation control mechanism suppresses rotation by an electric brake and temporarily stops the blade when the maximum rotation speed of the generator reaches 270 rpm. In FIG. 13, P indicates the output characteristics (power generation characteristics) of the generator, and a group of curves taking the wind speed as a parameter indicates the output characteristics of the windmill at that wind speed.

  FIG. 14 shows the prediction of power generation characteristics when the over-rotation control mechanism with a tuning mechanism of the present invention is operated. When the wind speed is 10 m / s or less where the pin 24 is in the straight portion 13a1 of the guide groove 13, the curve (characteristic curve) indicating the output characteristics of the windmill is almost the same as that without control in FIG. However, when the wind speed exceeds 10 m / s, the overspeed control functions, the maximum value of the characteristic curve of the wind turbine at each wind speed is suppressed to a small value, and even if the wind speed exceeds 15 m / s, the generator generates power. It has a curve P indicating characteristics and an intersection (operating point). According to theoretical prediction, even at a wind speed of 67 m / s, there is an intersection (operating point) with the power generation characteristic P of the generator, and power generation can be continued if the structural strength of the windmill can withstand strong winds. In FIG. 14, the characteristic curve of the wind turbine when the wind speed is 70 m / s and the twist angle is 35 degrees is indicated by a dotted line Q. In this state, the windmill cannot generate sufficient rotational force, and the intersection (operating point) with the power generation characteristic P of the generator is in a low rotational speed state of about 200 rpm. This means that if the maximum value of the twist angle is adjusted to 35 degrees or more by adjusting the characteristics of the compression coil spring or the shape of the guide groove, over-rotation control is possible even in a strong wind condition of 70 m / s or more. Means.

  FIG. 15 shows the power curves of two wind turbines, R with and without overspeed control. For convenience of calculation, in the case of over-rotation control, it was assumed that the generated power was a constant value (980.8 W) at a wind speed of 18 m / s. Moreover, since the wind speed appearance rate can be regarded as 0 at wind speeds of 31 m / s or higher, it is assumed that power generation at 31 m / s or higher is not performed (P = 0). That is, the cutout wind speed is 31 m / s. The cutout wind speed without control is 15 m / s.

  FIG. 16 is a comparison of annual power generation predictions of two wind turbines having the power curve shown in FIG. 15 when it is assumed that the wind speed appearance rate follows the Rayleigh distribution. When the annual average wind speed is 6 m / s or less, the amount of power generated by the wind turbine without S is slightly increased, but the difference is negligible. However, at wind speeds of 7 m / s or higher, the power generation amount of the wind turbine with overspeed control R is greater than that without control.

  Therefore, it can be said that the over-rotation control mechanism with a tuning mechanism of the present invention is effective in, for example, a region or mountainous region where the average wind speed is high in the polar region, or a remote island with a high typhoon passage rate.

  It should be noted that sudden winds may blow even in relatively mild wind conditions, so it goes without saying that using this windmill can be used with confidence because of improved safety. Further, as seen in the power curve of FIG. 15, the controlled R wind turbine can use a generator with a small rated output relative to the rated output of the uncontrolled S wind turbine, which has the merit of reducing costs. is there. The strong wind countermeasures and safety improvements will enable the provision of highly reliable small wind power generators.

DESCRIPTION OF SYMBOLS 11 Rotating hub 12 Frame 12a Through-hole 13 Cover 14 Universal joint 15 Vertical link 16 2nd hinge 17 Horizontal link 18 1st hinge 19 Tuning disk 21 Blade shaft 22 Blade 22a Blade attachment part 23 Flange part 24 Pin 25 Elastic body 26 Thrust bearing 31 Generator 32 Rotor rotating shaft

Claims (8)

A vertical having a rotating hub, a blade shaft that is held at one end by the rotating hub so as to extend in a radial direction from a rotation center of the rotating hub, and a blade that is attached to the other end of the blade shaft. An axial windmill,
The blade shaft can be moved in the radial direction by centrifugal force accompanying the rotation of the blade, and mounted so that the effective pitch angle and the wind receiving area of the blade can be changed by rotating around the radial direction as an axis. And
A vertical axis wind turbine comprising a restricting structure that restricts the radial movement and the rotation of the blade shaft. Until the blade reaches a predetermined centrifugal force, the blade shaft moves in the radial direction so that the wind receiving area of the blade is maintained at a predetermined area or more, and the blade is centrifuged at the predetermined centrifugal force or more. 2. The vertical structure according to claim 1, wherein when the force becomes a force, the blade shaft rotates with the radial movement to reduce the wind receiving area and increase the effective pitch angle. 3. Axial windmill. The blade shaft moves only in the radial direction until the blade has a predetermined centrifugal force. When the blade has a centrifugal force equal to or greater than the predetermined centrifugal force, the blade shaft rotates with the radial movement. The vertical axis wind turbine according to claim 2, wherein the restriction structure is formed as described above. The regulating structure guides the movement of the blade shaft in the radial direction and the rotation of the blade shaft, and a guide portion provided on one of the blade shaft and the periphery of the blade shaft; and The vertical axis wind turbine according to any one of claims 1 to 3, further comprising an engagement portion that is provided on the other of the blade shaft and the periphery of the blade shaft and engages with the guide portion. Of the guide portion, the portion where the blade shaft moves only in the radial direction is a linear portion along the radial direction, and the portion where the blade shaft both moves and rotates in the radial direction is: A rotational speed formed by a spiral part formed continuously with the linear part, and the length of the linear part along the radial direction corresponds to the rated rotational speed of the generator of the vertical axis wind turbine. The vertical axis wind turbine according to claim 4, wherein the blade axis is 30 to 80% of a distance in which the blade shaft slides in the radial direction by a centrifugal force acting on the blade when the blade rotates. 6. The rotating hub is provided with a plurality of blade shafts having the blades, and a tuning mechanism is provided so that rotation angles of the respective blade shafts by rotation are equal. The vertical axis windmill described in 1. A universal joint is connected to one end of the blade shaft, and the tuning mechanism includes a tuning disk provided coaxially with the rotation center of the rotation hub and rotated independently with respect to the rotation hub, The vertical axis wind turbine according to claim 6, wherein a first hinge formed on a constant radius from the center of the tuning disk and the universal joint are connected by a link having a predetermined length. A link connecting between the universal joint and the first hinge formed on the tuning disk includes a first link extending in a vertical direction from the universal joint, and a first link at a distal end portion of the first link. The vertical axis windmill according to claim 7, wherein the vertical axis windmill is formed by a second link extending in a horizontal direction between the first hinge on the tuning disk via two hinges.