JP2011132858A - Wind turbine for horizontal shaft type wind power generation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To employ a highly efficient blade shape which cannot be formerly employed due to a strength reason since a plurality of blades are supported in a cantilever style such as a blade shape in which a blade width extends toward a tip side, in a wind turbine for a so-called propeller type horizontal shaft type wind power generation device. <P>SOLUTION: Tips of the plurality of blades 4 attached to a hub 5 toward a radial direction at even angular intervals are connected to one another by an externally-connected rigid ring 6 formed in an annular shape, and the whole body of the wind turbine is constituted like a spoke wheel. As a result, the support style of each blade 4 is a stable both-end support in which base ends are supported by the hub 5 and tips are supported by the externally-connected rigid ring 6. The restriction of the blade shape peculiar to the cantilever style that a tip side needs to be lightened in weight is eliminated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a so-called propeller type windmill having a function of converting wind power into rotational force of a main shaft in a horizontal axis type wind power generator, and particularly, for use in a medium to large scale horizontal axis wind power generator. For suitable windmills.

  Wind turbines for wind power generators are roughly classified into a vertical axis type wind turbine in which the main shaft is arranged in the vertical direction and a horizontal axis type wind turbine in which the main shaft is arranged in the horizontal direction. The mainstream of current windmills is a horizontal axis type having a so-called propeller type blade arrangement. In the horizontal axis type wind turbine, the use of a large diameter wind turbine having a large sweep area is advantageous in terms of efficiency. In fact, the diameter of the wind turbine for the horizontal axis type wind power generator has been steadily increasing.

  However, it must be said that the penetration rate of wind power generation in Japan is low even though the necessity is always asserted from the viewpoint of reducing greenhouse gases. As factors that inhibit the spread of wind power generation, there are physical and social factors.

  The physical obstacles include the narrow and complex land conditions unique to Japan and the complicated and unstable weather environment accompanied by strong winds and lightning strikes, as well as sufficient power generation with a low average wind speed compared to Western Europe. It cannot be obtained. Such wind conditions are a major obstacle to the installation of wind power generation facilities. On the other hand, as a social hindrance factor, the instability of power generation due to weather fluctuations unavoidable for natural energy power generation such as windmills due to the weakness of the power grid in Japan, and instability factors to the power system due to this Can be mentioned.

  In order to disseminate wind power generation in such an environment, it is necessary to consider in advance what kind of wind power generation apparatus is suitable for Japan's land and wind conditions.

  In view of the narrow national land circumstances, it is preferable that the installation area is as small as possible. In addition to the site directly occupied by the foundation structure of the wind power generator, the installation site includes areas where access is effectively restricted. From this, if the ground area for installation is the same, a safe windmill with a larger amount of power generation than that installation area is desired.

  That is, conventionally, in a large-diameter windmill, the plurality of radially arranged blades 1 are supported only by the central hub 3 and are supported in a cantilever manner as a whole (see FIG. 8). . In such a support form of the blade 1, the weight of the blade increases as the wind turbine becomes larger, and the design limit for ensuring the required strength of the cantilever support portion is reached. In particular, the hub 3 and the blade 1 need to adjust the pitch angle (mounting angle) of the blade 1, and therefore, a special and expensive bearing 2 that supports a huge moment load is used. It has become increasingly difficult.

  In addition, in response to a strong request to reduce the weight of the blade based on such circumstances, it is necessary to use a more expensive, lighter and stronger material, and it is necessary to reduce the weight and load at the tip where the weight loss effect is remarkable, Tapered blade shapes are becoming mainstream at the expense of some efficiency. Furthermore, when the blade tip is open in this way, wind turbines are introduced not only because of the loss of efficiency due to the vortex generation of the air flow at the tip, but also because of the risk of the sound generated at the blade tip affecting the private house. It has become an obstruction factor. In addition, such a demand for weight reduction results in the reduction of the rotational inertia of the blades, so that the output of power generation is affected by wind fluctuations, and there is a problem in connection to the power system.

  Originally, for the purpose of increasing the efficiency of the windmill and generating a large torque on the main shaft, the blade shape is not the tapered shape that is the mainstream of the current windmill design, but conversely the shape that the blade tip end side is enlarged Is preferred. However, in such a blade shape, when the center of gravity of the blade moves relatively to the tip end side of the blade and the point of action of the load moves to the tip end side, the base portion of the blade that is an attachment portion to the main shaft or the hub A large moment load is applied to the. Therefore, some countermeasure is required for this problem. In addition, when the blade shape is an enlarged tip shape, some contrivance is required for processing the blade tip.

  Next, a technical example aimed at improving conformity to the national and wind conditions of Japan will be used as a reference.

JP-A-3-44229 No. 7-54622

  From the above examination, the present invention assumes a windmill having a diameter corresponding to the scale as a medium-sized or large-scale wind power generation apparatus, and is adopted in a large-diameter windmill within the limit of the diameter of the assumed windmill. By making it possible to adopt high-efficiency blade shapes that could not be achieved by eliminating the limiting factors for adopting the blade shapes, it is possible to efficiently use local winds that are subject to rapid fluctuations. An object is to provide a windmill for a horizontal axis wind power generator. By adopting a highly efficient blade shape, a wind turbine with the same diameter can be expected to improve efficiency by 20% or more compared to the conventional tapered shape.

  A wind turbine for a horizontal axis wind power generator according to the present invention is a wind turbine for a horizontal axis wind power generator in which a plurality of blades are radially arranged on a hub in a radial direction. A high-efficiency shape with good conversion efficiency for conversion to lift is adopted, and the tip portions of a plurality of blades are connected to each other by a ring-shaped circumscribed rigid body ring.

  In the wind turbine having the above-described configuration, tip portions of a plurality of blades arranged radially with respect to the hub are connected to each other by a circumscribed rigid body ring. Prior to attaching the circumscribed rigid ring, each conventional blade is, as it were, cantilevered or cantilever supported by a hub, and the tip side is an unconstrained free end. In this state, lift force, drag force, inertia property, or a combined load of these, and a fluctuating load due to the weight of the rotating blade, all become a concentrated moment load only on the base of the blade. However, as described above, the tips of the plurality of blades are connected to each other by the circumscribed rigid ring, so that the wind turbine as a whole becomes a support mode in which both ends of each blade are freely supported by the hub and the circumscribed rigid ring. Therefore, the moment load at the connection portion of each hub and the circumscribed steel body ring can be made zero. For this reason, it is possible to select a bearing that is very small and inexpensive as the bearing used in this connecting portion. The hub and the circumscribing rigid ring constitute an integrated structure similar to a spoke wheel. Therefore, the external force derived from the wind force acting on the blade is not concentrated on the base of the blade, but distributed throughout the hub and the circumscribed rigid ring, so the restrictions in selecting the blade shape are eliminated, and the efficiency A preferential blade shape can be employed. The circumscribed rigid ring also functions as a member that connects the tip of the blade in a ring shape, so that it does not generate turbulent flow at the tip of the blade, contributing to efficiency improvement, and the ring-like object is in the air The blade is imparted with the effect that no turbulent flow or wind noise is generated even if it rotates. Furthermore, the moment load generated in the blade member is less than half that of a cantilever, making it easy to design in strength and eliminating the need for weight reduction. The material can be used.

  The blade shape of the wind turbine for the horizontal axis wind power generator according to the present invention may be a blade shape in which the blade width increases toward the tip side.

  The blade area is the basis for generating lift, which is the driving force for rotating the windmill. The lift generated in each part of the blade is converted into torque in proportion to the length of the blade as a moment arm at the generation position. In other words, when the same lift force is generated at the base portion and the tip portion of the blade, the lift force generated at the tip portion is converted into a larger torque. Therefore, even when the entire area of the blade is the same, the lift generated in the blade can be more effectively converted into torque by setting the blade shape so that the blade width increases toward the tip of the blade. .

  The wind turbine for a horizontal axis wind power generator according to the present invention can be configured such that a spoke frame for connecting a hub and a circumscribed rigid ring is disposed between a plurality of adjacent blades.

  With the configuration in which the hub and the circumscribed rigid body ring are connected by a spoke frame that is a dedicated connecting member, the blade can be released from the burden of the connecting member that connects the hub and the circumscribed rigid ring. Therefore, it is possible to adopt a more ideal high-efficiency shape as a blade shape, and it becomes extremely easy to adopt a variable pitch blade with adjustable pitch angle.

  A wind turbine for a horizontal axis wind power generator according to the present invention includes an intermediate ring formed concentrically between a hub and a circumscribed rigid ring, and a blade and a spoke frame, and the intermediate ring and the circumscribed rigid ring. It can be set as the structure arrange | positioned between.

  In the wind turbine configured as described above, the base portions of the plurality of blades and the spoke frame are all attached to the intermediate ring and attached to the hub via the intermediate ring. These members, if there is no intermediate ring, are all attached directly to the hub, resulting in complex stress concentration on the hub and complicating the strength design of the hub, but interposing the intermediate ring By using the intermediate ring to level the load such as the centrifugal force generated by the blade or the rotation of the blade, the hub can be loaded with the load after leveling the total weight, wind load, etc. Hub design can be facilitated.

  The plurality of blades in the wind turbine having the spoke frame in the horizontal axis wind power generator of the present invention can be pitch-adjustable.

  By adopting a blade with adjustable pitch, it is possible to set the angle of attack of the blade that is most likely to obtain lift in accordance with changes in the wind speed. Feathering operation as a countermeasure is also possible. In a wind turbine equipped with a spoke frame, since the spoke frame is responsible for the integration function of the intermediate ring and the circumscribed rigid ring, the structure of connecting the blade to the intermediate ring and the circumscribed rigid ring in a pitch-adjustable manner is also possible. It does not affect the overall strength at all.

  The wind turbine for a horizontal axis wind power generator according to the present invention can be configured to use a circumscribed rigid ring as a flywheel.

  Since the circumscribed rigid body ring is located at the tips of the plurality of blades, it can exert a large rotational inertia action when the windmill rotates. In other words, the circumscribed rigid ring is designed to level the power output by temporarily storing wind energy as mechanical inertia energy and releasing it later as mechanical inertia energy due to its large rotational inertia. And stable operation of the wind turbine can be realized. This solves a social problem in connecting the power generated from the windmill to the power system until now.

  The wind turbine for a horizontal axis wind power generator according to the present invention may be configured such that the circumscribed rigid body ring is surrounded by a reduced diameter portion of a short cylindrical air collecting ring having a reduced diameter portion with a reduced diameter in the middle portion. it can.

  The air collecting ring has a reduced diameter portion with a reduced diameter at the intermediate portion. As a result, the air collecting ring has an overall shape in which the opening portions at both ends expand outward. The wind is introduced into the air collecting ring by the air collecting effect of the opened opening, is accelerated by the venturi effect when passing through the reduced diameter portion, and is smoothly discharged from the other opening. At this time, since the entire windmill is located within the reduced diameter portion, the wind accelerated at each blade can be effectively applied. Moreover, this wind collection ring can generate a negative pressure in the wake part of a windmill by adjusting the shape appropriately. Thereby, the effect | action which attracts | sucks the air from the front of a windmill generate | occur | produces, and more winds can be called in to a windmill and the improvement of further efficiency can be anticipated. Experimentally, there is data that can achieve an efficiency improvement of 2 to 2.5 times.

  A wind turbine for a horizontal axis wind power generator according to the present invention is a circumscribed rigid body formed in an annular shape in a wind turbine for a horizontal axis wind power generator in which a plurality of blades are radially arranged on a hub in a radial direction. By connecting the tips of a plurality of blades to each other by a ring, the entire wind turbine is configured as a hub, a plurality of blades, and a circumscribed rigid ring as a strong structure like a spoke wheel having a plurality of blades as spoke members. In addition, since the configuration in which the tip portion of each blade is surrounded by a circumscribed rigid ring is realized, it is efficient that the blade cannot be employed in a conventional wind turbine in which the blade is fixed to the hub in an independent state. For example, the blade shape can be adopted without revealing the problem of wind noise and low frequency noise from the blade tip. Therefore, it is possible to provide a wind turbine suitable for use in a medium-sized or large-scale horizontal axis wind power generator capable of efficiently using local winds that are fluctuating rapidly. Furthermore, since the circumscribed rigid ring can level the rotational fluctuation of the windmill by an effective rotational inertia action, a wind power generator having a stable output can be realized even in an installation environment where the wind speed fluctuates.

It is a front view showing typically a 1st embodiment of a windmill of the present invention. It is AA arrow sectional drawing of FIG. 1 which concerns on the said embodiment. It is a front view which shows typically 2nd Embodiment of the windmill of this invention. It is a BB arrow directional cross-sectional view of FIG. 3 which concerns on the said embodiment. It is a front view which shows typically 3rd Embodiment of the windmill of this invention. It is CC sectional view taken on the line of FIG. 5 which concerns on the said embodiment. It is a principal part enlarged view which shows typically 4th Embodiment of the windmill of this invention. It is a front view which shows the conventional windmill typically.

  Hereinafter, a wind turbine for a horizontal axis wind power generator according to an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description of the embodiment, the center axis S will be described from the standpoint of the wind turbine component, but the center axis S is a member that can be considered as a wind turbine mounting member. Take note.

(First embodiment)
The windmill includes at least a central axis S, a hub 5 that is externally fitted to the central axis S and is configured to be fixed or rotatable to the central axis S, a plurality of blades 4, and an annular circumscribed rigid ring 6. And with spoke frames 7 as required (FIGS. 1 and 2). The hub 5 is attached to the central axis S, and the plurality of blades 4 are radially attached to the hub 5 at equal angular intervals in the radial direction of the central axis S. Further, the circumscribed rigid ring 6 is attached to the blades 4 in such a manner that the tips of the plurality of blades 4 are connected to each other.

  The central shaft S can be a mounting member for the hub 5 and at the same time a torque transmission member. There is no specific requirement for the central axis S in the present invention, and it is sufficient that the central axis S has a general solid axial shape or a hollow tubular shape. The central shaft S may be configured such that a shaft joint having an elastic element, a play element, a telescopic element, or a free element is interposed in the middle.

  The hub 5 is a member for expanding the outer diameter of the central axis S, and at the same time, an attachment member for the plurality of blades 4. Due to the presence of the hub 5, it is possible to adopt a convenient assembling procedure for assembling the plurality of blades 4 to the hub 5 in advance and assembling the hub 5 having the necessary number of blades 4 to the main shaft S.

  In general, large wind turbines in recent years include three blades 4. Regarding the number of blades 4..., Three blades are conventionally reasonable. This point is the same in this embodiment, but different numbers of blades are not necessarily deviated from the technical idea of the present invention. It is possible to provide. Each blade 4 is a surface member having a blade function for converting wind power into lift. Each blade 4 has a shape in which the blade width increases from the base side attached to the hub 5 toward the tip side, and is provided with a twist angle necessary for effectively capturing wind. Note that the twist angle can be made almost zero by selecting an appropriate degree of spread of the blade width. In this case, the manufacturing cost of the blade is greatly reduced.

  In addition, the blade shape in which the blade width expands toward the tip side is not only a shape in which the blade width per unit length of the blade is proportionally expanded at a constant expansion rate, but the expansion rate may change midway And the case of enlarging. Further, the blade shape whose blade width increases toward the tip side is merely an example of the blade shape that is a highly efficient shape referred to in the present invention, and a highly efficient blade shape that is tapered from another design viewpoint is adopted. It is also possible. Accordingly, the present invention naturally includes tip support of the tapered blade by the circumscribed rigid ring 6. Further, the high efficiency of the blade 4 includes those in which the leading edge and the trailing edge of the blade are rounded, and conventional means for forming the cross-sectional shape into a shallow bow shape. The blades 4... In this form can be manufactured at low cost, whether they are made of reinforced resin or metal. As the structure of the blades 4 in a relatively large-diameter wind turbine, a structure in which an exterior plate is attached to a framework of a rib structure similar to an aircraft wing can be employed.

  The circumscribed rigid ring 6 is a structural member unique to the present invention. The circumscribed rigid ring 6 is an annular member having a diameter circumscribing the tips of the plurality of blades 4. The circumscribed rigid ring 6 can be made of a hollow or solid resin or metal, and need not be integral with any material. For example, a circle formed by 1/3 arc unit of the whole circle may be connected to form an annular shape. However, attention should be paid to the balance in rotational motion.

  The spoke frames 7 are force-bearing members that are arranged in such a manner that the hub 5 and the circumscribed rigid body ring 6 are connected to each other at an angular intermediate position between the three blades 4 attached at an angular interval of 120 degrees. The requirement for the spoke frame 7 is that the wind draft is good. For this reason, the spoke frame 7 can achieve its purpose by arranging a pipe frame structure made of a strong thin steel pipe material such as high tension steel or a wire rope in a spoke shape. As a specific example, two sets of spokes 7A, 7A, which are one set via two horizontal bars 7B, 7B, are allocated and arranged at equal angles between adjacent blades 4, 4, and two sets of spokes 7A, 7A is connected by connecting pipes 7C and 7C.

  Since the circumscribed rigid ring 6 in the present embodiment has a large rotational inertia due to its own weight and rotational radius, it can be used as a flywheel. And no special work is required for this purpose. In other words, this object can be achieved by omission of making no effort to reduce the weight of the circumscribed rigid ring 6. On the other hand, when the inertia component becomes excessive due to the large diameter of the windmill, measures for reducing the material and structure of the circumscribed rigid ring 6 are necessary. For example, the use of a resin material, the use of a lightweight high-strength metal material such as ultra-super duralumin, and the appropriate blanking process.

(Second Embodiment)
The wind turbine for a horizontal axis wind power generator according to the present invention can include an intermediate ring 9 in addition to the circumscribed rigid ring 6 (FIGS. 3 and 4). The intermediate ring 9 is arranged concentrically about the main axis S between the hub 5 and the circumscribed rigid ring 6. The intermediate ring 9 has a smaller diameter than the circumscribed rigid ring 6, but has the same structure as the circumscribed rigid ring 6. The functions to be borne by the intermediate ring 9 are a function as an attachment member at one end of the three blades 8... And the three spoke frames 7 and dispersion of concentrated stress on the hub 5.

  Further, the intermediate ring 9 itself is connected to the hub 5 via three substantially frustoconical support members 11, whose outer shape is adjusted so as to reduce wind resistance. The three support members 11 are distributed at equal angular intervals corresponding to the attachment positions of the three blades 4 to the intermediate ring 9. Each support member 11 abuts on the hub 5 with a wide bottom area and functions so that stress concentration on the hub 5 does not occur. As for the connection between the intermediate ring 9 and the hub 5, an appropriate connection means can be adopted according to the size of the inner area of the intermediate ring 9. Further, although the support member 11 depends on the space relationship between the hub 5 and the intermediate ring 9, it is possible to contribute to an improvement in the efficiency of the windmill by making the shape into a blade shape. In any case, it can be said that this is a form in which the stress concentration on the hub 5 is less.

(Third embodiment)
The wind turbine for a horizontal axis wind power generator according to the present invention can include a wind collecting ring 13 outside the circumscribed rigid ring 6 (FIGS. 5 and 6).

  The air collecting ring 13 is a short cylindrical ring member having a reduced diameter portion 13D formed by a tapered surface whose openings at both ends expand outward and having a diameter narrowed at an intermediate portion. The inner diameter of the reduced diameter portion 13D of the air collecting ring 13 is set to be slightly larger than the outer diameter of the circumscribed rigid body ring 6, and is fixedly installed on the support base 14 so as to surround the circumscribed rigid body ring 6 by the reduced diameter portion 13D. It is done. The support base 14 is normally supported by a yaw control mechanism. That is, the air collecting ring 13 does not rotate with the windmill, but can follow the wind direction change with the windmill. FIG. 6 schematically illustrates the air collecting ring 13, and the inner wall surface of the air collecting ring 13 preferably has a smooth curved surface configuration.

  In addition to the basic action of collecting and increasing the wind speed, the wind collecting ring 13 avoids direct lightning strikes on the windmill, lowers the wind turbine operating noise due to the enclosure effect, and uses an appropriate net member for the opening. By blocking, it is possible to exhibit derivative functions such as avoiding foreign flying objects and capturing falling objects from the windmill when an accident occurs.

(Fourth embodiment)
Among the wind turbines for the horizontal axis type wind power generator of the present invention, any one having the spoke frame 7 can employ a variable pitch blade 8 capable of pitch driving (FIG. 7).

The variable pitch blade 8 includes support shafts 8J and 8J at the distal end portion and the proximal end portion of the blade. Supporting shaft 8J of the tip is assembled via a radial bearing X ₁ circumscribed rigid ring 6, also, the support shaft 8J proximal end, the hub 5 or the intermediate ring via a radial thrust composite bearing X ₂ 9 Assembled into. Pitch driving for the variable pitch blade 8 is performed by driving the support shaft 8J on the base end side by a pitch driving mechanism (not shown). The pitch drive mechanism is normally housed in the hub 5 and can be connected to the variable pitch blade 8 using an extension shaft as required. Since the variable pitch blade 4 is configured to support both the distal end portion and the proximal end portion, no momentary load is applied to the radial support bearing X ₁ and the radial / thrust composite bearing X _2. A smooth pitch driving operation can be realized by a pitch driving mechanism that generates a small amount of torque and has a small output.

S central axis,
4 blades,
5 Hub,
6 circumscribed rigid body ring,
7 spoke frame,
8 Variable pitch blade

Claims (7)

In a wind turbine for a horizontal axis wind power generator in which a plurality of blades are radially arranged on a hub in a radial direction,
As the blade shape of the blade, a high-efficiency shape with good conversion efficiency for converting wind power into lift is adopted, and the tip portions of a plurality of blades are connected to each other by a ring-shaped circumscribed rigid ring. Wind turbine for horizontal axis wind power generator.   2. The wind turbine for a horizontal axis wind power generator according to claim 1, wherein the blade shape is a blade shape in which a blade width increases toward a tip portion.   The spoke frame for connecting the hub and the circumscribed rigid body ring is disposed between the plurality of blades adjacent to each other, wherein the spoke frame is used for the horizontal axis wind power generator according to claim 1 or 2. Windmill.   An intermediate ring formed annularly between the hub and the circumscribed rigid ring is disposed concentrically, and the plurality of blades or / and the spoke frame are disposed between the intermediate ring and the circumscribed rigid ring. The wind turbine for a horizontal axis wind power generator according to any one of claims 1 to 3, wherein the wind turbine is a wind turbine.   The wind turbine for a horizontal axis wind power generator according to claim 3 or 4, wherein the plurality of blades are adjustable in pitch.   The wind turbine for a horizontal axis wind power generator according to any one of claims 1 to 5, wherein the circumscribed rigid body ring is used as a flywheel.   7. The circumscribed rigid body ring is surrounded by a reduced diameter portion of a short cylindrical air collecting ring having a reduced diameter portion with a reduced diameter at an intermediate portion. Wind turbine for horizontal axis wind power generator.

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