WO2020060063A1

WO2020060063A1 - Spiral blade having improved injection moldability and spiral blade unit having the same

Info

Publication number: WO2020060063A1
Application number: PCT/KR2019/011056
Authority: WO
Inventors: Joon Ho Baek; Marinus Mieremet; Heung Guen YANG; Yong Joo Chun; Myoung Gon Kim
Original assignee: Esco Rts Co., Ltd.
Priority date: 2018-09-19
Filing date: 2019-08-29
Publication date: 2020-03-26

Abstract

Disclosed is a spiral blade configured such that a spiral blade having a spiral plate portion formed on the outer peripheral surface of a divided shaft and having an excellent quality can be fabricated through injection molding without generating an undercut, thereby substantially improving the productivity of a spiral blade unit. The spiral blade includes: a root portion fixed to a rotating shaft; a spiral plate portion molded spirally and a partial shaft portion formed integrally along the root portion. The range of angle at which the root portion of the spiral plate portion is connected around an outer peripheral surface of the partial shaft portion is equal to or larger than a 240° range and is equal to or smaller than a 350° range.

Description

SPIRAL BLADE HAVING IMPROVED INJECTION MOLDABILITY AND SPIRAL BLADE UNIT HAVING THE SAME

Various types of wind power generators are known. The present invention relates to improvement of spiral blades that can be appropriately used for such a wind power generator and a spiral blade unit having such blades.

In general, a wind power generator includes a blade unit having a rotating shaft and multiple blades coupled to the rotating shaft and arranged around the rotating shaft so as to obtain rotational power from wind.

A spiral blade unit having spirally configured blades has a complicated shape and has multiple (preferably three) blades attached to the outer peripheral surface of the rotating shaft. This arrangement structure makes it very difficult to integrally fabricate the entire unit through injection molding or casting. Accordingly, individual spiral blades are fabricated separately from the rotating shaft, and then firmly fixed to the outer peripheral surface of the rotating shaft at a predetermined angular interval, thereby obtaining a spiral blade unit. If necessary, spiral blades are formed integrally with divided rotating shafts, and then coupled to each other through the divided rotating shafts, thereby obtaining a spiral blade unit. However, fabrication through injection molding is very difficult in this case as well, because each spiral blade is formed to have a spiral plate portion wound around the outer peripheral surface of a divided shaft.

The present invention relates to improvement of spiral blades used to manufacture such a spiral blade unit, and spiral blade units having such spiral blades.

A comparison between a spiral blade unit having spiral blades applied thereto and a blade unit having normal blades applied thereto shows that, since the ratio of the area that receives wind within the rotating area of each blade of the spiral blade unit is much larger than that of the blade unit, each blade of the spiral blade unit may undergo bending deformation when receiving a strong wind, and the imbalance between forces acting on respective blades may cause severe vibrations, thereby fracturing the blades. In an attempt to solve such problems, inventors of the present invention developed and patented an approach to connect spiral blades by using blade connectors.

Prior art documents of the present invention in this regard include Korean Registered Patent No. 10-1592289 (SPIRAL BLADE UNIT AND METHOD FOR MANUFACTURING SAME), Korean Registered Patent No. 10-1578745 (SPIRAL BLADE UNIT, WIND POWER GENERATOR, AND BLADE CONNECTOR FOR SPIRAL BLADE UNIT), and Korean Registered Patent No. 10-1612238 (SPIRAL BLADE UNIT AND WIND POWER GENERATOR), which were developed and patented by inventors the present invention (Jun-ho Baek, Mieremet Mariners, et al.).

In the above prior art documents, separate inclined members are employed besides washers and nuts, in order to fix connecting members to spiral blades, and the separate inclined members have inclined surfaces formed thereon so as to compensate for inclination resulting from curved surfaces of the spiral blades.

The conventional inclined members have surfaces configured to make surface contact with spiral blades, and the surfaces need to be formed to match with surfaces of the spiral blades. Such inclined members are very difficult to manufacture because the surfaces of the spiral blades are curved, not planar.

There is another problem in that, since the surface of a spiral blade has a different curved shape depending on the position, individual inclined members having different shapes of curved surfaces, depending on the installation position, need to be fabricated separately, thereby substantially increasing the manufacturing cost.

The surface of an inclined member, which is to contact the surface of a spiral blade, may be formed in a planar shape because the area of contact with the spiral blade is not large. However, such formation may degrade the performance of firmly connecting and supporting spiral blades, and may result in concentrated application of load to narrow parts of the spiral blades, or may cause gaps formed between edges of the inclined members and the spiral blades, thereby causing noise generation.

In an attempt to solve the above-mentioned problems, it may be envisioned to integrally form a protrusion-type inclined portion, which has an inclined surface, on the surface of a spiral blade instead of fabricating a separate inclined member. However, such an approach is unprecedented in the technical field of the present invention, and thus there is a need for research and inventive endeavors to make the same concrete and practical.

The present inventors continued research on fabricating high-quality spiral blades having divided shafts through injection molding, in order to improve the productivity of spiral blades and spiral blade units, and found as a result a problem in that undercuts occurred in root portions or the like of spiral plate portions during injection molding.

An object of the present invention is to provide a spiral blade configured such that, when a spiral blade having a divided shaft is injection-molded, it is possible to prevent an undercut from occurring to the root portion or the like of the spiral plate portion.

Another object of the present invention is to provide a spiral blade which has a spiral plate portion formed around a divided shaft, and which has excellent injection moldability, and a spiral blade unit employing the same.

Another object of the present invention is to provide a spiral blade and a spiral blade unit employing the same, wherein the spiral blade can be fabricated through injection molding such that a spiral plate portion is formed around a spilt shaft, and the thickness thereof can be easily adjusted according to the position of the spiral plate portion.

Another object of the present invention is to add the function of an inclined member for safely fixing a connecting member, disclosed in the prior art, to a blade itself.

Another object of the present invention is to ensure that, when a connecting member and a spiral blade are fixed to each other, a fastener and the spiral blade make surface contact, thereby preventing fracture due to stress concentration, wear, and the like, and improving the stability and durability of the spiral blade.

Another object of the present invention is to provide spiral blades which can be firmly connected to each other and supported through blade connectors, without separate inclined members, and a spiral blade unit having such blades.

Another object of the present invention is to provide spiral blades and a spiral blade unit having the same, wherein each spiral blade has a connecting member fixing portion integrally formed on the surface so as to replace a conventional inclined member, and degradation of performance of the spiral blade unit due to discontinuity of the spiral surface can be minimized.

Another object of the present invention is to provide spiral blades and a spiral blade unit having the same, wherein the configuration of connecting member fixing portions formed integrally on the surface of the spiral blades is optimized such that air resistance due to installation of the connecting member fixing portions is minimized, and multiple spiral blades are firmly connected such that no shape change of the spiral blades occurs.

Another object of the present invention is to provide spiral blades and a spiral blade unit having same, wherein the spiral blades are easy to fabricate and can remain firmly fixed to a rotating shaft.

A spiral blade according to the present invention has a root portion fixed to a rotating shaft and a spiral plate portion formed spirally so as to be positioned away from the root portion in a radial direction of the rotating shaft such that rotational power can be obtained from a fluid flowing in a longitudinal direction of the rotating shaft, the spiral plate portion having a spiral surface formed thereon, the spiral blade comprising; a partial shaft portion formed integrally along the root portion so as to constitute a part of the rotating shaft, wherein the range of angle at which the root portion of the spiral plate portion is connected around an outer peripheral surface of the partial shaft portion is equal to or larger than a 240° range and is equal to or smaller than a 350° range.

Preferably, the range of angle at which the root portion of the spiral plate portion is connected around the outer peripheral surface of the partial shaft portion is equal to or larger than a 270° range and is equal to or smaller than a 330° range.

Preferably, an inflection connecting portion is formed on a leading edge side of the spiral plate portion so as to be bent from a spiral shape toward a center of the rotating shaft and to be connected to the partial shaft portion such that the range of angle at which the root portion of the spiral plate portion is connected to the outer peripheral surface of the partial shaft portion is reduced.

Preferably, the partial shaft portion has a non-circular section groove formed near a center portion of the rotating shaft, and the outer peripheral surface of the partial shaft portion has a straight portion and a twist portion along the longitudinal direction of the partial shaft portion.

Preferably, the spiral blade includes multiple connecting member fixing portions arranged at an interval along a leading edge of the spiral plate portion and formed integrally with the spiral plate portion so as to protrude from the spiral surface toward at least one of front and rear directions; holes are bored in protruding parts of the connecting member fixing portions such that a connecting member passes therethrough; and the connecting member fixing portions have surface-contact fastening surfaces formed thereon such that fasteners can be fixed to the connecting member while making surface contact with the front and rear surfaces around the holes.

Preferably, the surface-contact fastening surfaces include planar surfaces or spherical surfaces, and a hole is formed in a leading edge of the spiral plate portion between the connecting member fixing portions arranged at an interval such that the connecting member passes therethrough.

The connecting member fixing portions may be formed in cap shapes such that one of the front and rear surfaces thereof is convex and the other thereof is concave, or both the front and rear surfaces thereof may be convex, may have identical shapes, and may be arranged in opposite directions.

If necessary, the connecting member fixing portions may be arranged so as to be elongated in the circumferential direction, instead of in the radial direction, and to be inclined in the circumferential direction.

A hole may be formed in at least one part between both ends of the root portion such that a band passes therethrough so as to bind partial shaft portions of multiple spiral blades.

Preferably, the partial shaft portion is formed in a 120° angle range in a shape obtained by equally dividing the rotating shaft into three, and the non-circular section groove is a V-shaped non-circular section groove having an angle of 120° between inner peripheral surfaces thereof.

A spiral blade unit according to the present invention includes at least two spiral blades according to the present invention, which are coupled to each other through partial shaft portions.

Preferably, the spiral blade unit includes: A connecting member inserted into holes of connecting member fixing portions, which are arranged on a same straight line, of the at least two spiral blades; and multiple fasteners coupled to the connecting members from front and rear surfaces of the at least two spiral blades, respectively, and configured to maintain surface contact with surface-contact fastening surfaces of the connecting member fixing portions arranged on the same straight line such that the spiral blades are fixed and prevented from moving with regard to the connecting member.

Preferably, the three spiral blades are configured to be coupled to each other through the partial shaft portions, and the surface-contact fastening portions arranged on the same straight line are arranged in parallel to each other.

Preferably, the fasteners include washers coupled to outer peripheral surfaces of the connecting members, and nuts coupled to threads formed on the connecting members so as to pressurize the washers toward the surface-contact fastening surfaces.

A non-circular section hole may be formed inside the partial shaft portions coupled to each other, and a non-circular section shaft member may be coupled to the non-circular section hole.

According to the present invention, it is possible to fabricate a high-quality spiral blade having a spiral plate portion formed on the outer peripheral surface of a divided shaft through injection molding, thereby substantially improving the productivity of a spiral blade unit.

According to the present invention, it is possible to produce a large amount of spiral blades having spiral plate portion formed on the outer peripheral surface of divided shaft (hereinafter, referred to as partial shaft portion) through injection molding, and the thickness of the spiral blades can be appropriately adjusted according to the position of the spiral plate portions, thereby enabling mass production of optimized spiral blade units.

According to the present invention, the time and cost to fabricate separate inclined members can be reduced, and connecting member fixing portions can be formed according to a blade manufacturing method and optimized for spiral blades such that spiral blades are firmly connected to each other.

According to the present invention, air resistance resulting from formation of connecting member fixing portions can be minimized.

According to the present invention, spiral blades can be firmly connected to each other, and the spiral blades can remain firmly coupled to a rotating shaft.

The above and other aspects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an enlarged perspective view illustrating an example of a spiral blade according to the present invention;

FIG. 2 is an enlarged perspective view of the spiral blade illustrated in FIG. 1, seen from the rear surface;

FIG. 3 is an enlarged view of a connecting member fixing portion, seen from a side surface, and FIG. 4 is an enlarged view of the connecting member fixing portion, seen from another side surface;

FIG. 5 is a side view of a spiral blade unit according to the present invention, which has three spiral blades illustrated in FIG. 1 installed around a rotating shaft at an interval of 120°;

FIG. 6 is a side view of a spiral blade unit according to the present invention, wherein spiral blades illustrated in FIG. 5 are connected to each other by using connecting members and fasteners;

FIG. 7 is an enlarged perspective view illustrating a state in which a connecting member is fixed to a connecting member fixing portion through a fastener, seen from the front surface, and FIG. 8 is an enlarged perspective view illustrating a state in which the connecting member is fixed to the connecting member fixing portion through the fastener, seen from the rear surface;

FIG. 9 is an enlarged perspective view illustrating another example of the spiral blade according to the present invention;

FIG. 10 is an enlarged perspective view of the spiral blade illustrated in FIG. 9, seen from the rear surface;

FIG. 11 is an enlarged perspective view of the spiral blade illustrated in FIG. 9, seen from the front surface;

FIG. 12 is an enlarged view of an example of the connecting member fixing portion, and FIG. 13 is an enlarged view of another example of the connecting member fixing portion;

FIG. 14 is a side view of a spiral blade unit according to the present invention, wherein the spiral blades illustrated in FIG. 9 are coupled through partial shaft portions;

FIG. 15 is a side view of a spiral blade unit according to the present invention, wherein spiral blades are connected by using multiple connecting members and fasteners;

FIG. 16 is a perspective view illustrating a variant example of the spiral blade illustrated in FIG. 9;

FIG. 17 illustrates another example of the connecting member fixing portion, and FIG. 18 illustrates another example of the connecting member fixing portion;

FIG. 19 is an enlarged perspective view illustrating another example of the spiral blade according to the present invention;

FIG. 20 is an enlarged front view of the spiral blade illustrated in FIG. 19;

FIG. 21 is a perspective view of a spiral blade unit obtained by assembling three spiral blades illustrated in FIG. 19 and non-circular section shaft members;

FIG. 22 is a front view of the spiral blade unit illustrated in FIG. 21;

FIGS. 23A to 23F are side perspective views of the spiral blade illustrated in FIG. 19, which is rotated sequentially by 60 degrees; and

FIG. 24 illustrates another example of the partial shaft portion and the non-circular section shaft member, and FIG. 25 illustrates still another example of the partial shaft portion and the non-circular section shaft member.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an enlarged perspective view illustrating an example of a spiral blade according to the present invention. FIG. 2 is an enlarged perspective view of the spiral blade illustrated in FIG. 1, seen from the rear surface. FIG. 3 is an enlarged view of a connecting member fixing portion, seen from a side surface, and FIG. 4 is an enlarged view of the connecting member fixing portion, seen from another side surface. FIG. 5 is a side view of a spiral blade unit according to the present invention, which has three spiral blades illustrated in FIG. 1 installed around a rotating shaft at an interval of 120°. FIG. 6 is a side view of a spiral blade unit according to the present invention, wherein spiral blades illustrated in FIG. 1 are connected to each other by using connecting members and fasteners. FIG. 7 is an enlarged perspective view illustrating a state in which a connecting member is fixed to a connecting member fixing member through a fastener, seen from the front surface, and FIG. 8 is an enlarged perspective view illustrating a state in which the connecting member is fixed to the connecting member fixing member through the fastener, seen from the rear surface.

As can be understood from FIG. 1 to FIG. 8, the spiral blade 110 according to the present invention includes a root portion 111 for fixing the same to a rotating shaft 130, and a spiral plate portion 112 molded spirally so as to be positioned away from the root portion 111 in the radial direction of the rotating shaft such that rotational power can be obtained from a fluid flowing in the longitudinal direction of the rotating shaft 130, the spiral plate portion 112 having spiral surfaces 112a formed on the front and rear surfaces thereof, respectively.

Preferably, the root portion 111 is formed to have a portion 111a connected to the rotating shaft 130 straightly, and a portion 111b connected thereto while winding spirally along the circumference of the rotating shaft 130.

The spiral blade 110 has multiple connecting member fixing portions 120 formed at an interval along the leading edge thereof such that spiral blades 110 installed on a rotating shaft 130 can be connected to each other.

The connecting member fixing portions 120 are formed integrally with the spiral plate portion 112 so as to protrude from the spiral surface 112a toward at least one of the front and rear directions. Each connecting member fixing portion 120 has a hole 121 formed at a protruding part thereof such that a connecting member 150 passes through the same, and has surface-contact fastening surfaces 122 formed on the front and rear surfaces around the hole 121 such that fasteners 160 can be fixed to the connecting member 150 while fasteners 160 make surface contact therewith. The surface-contact fastening surfaces 122 are preferably formed to be planar. If necessary, the surface-contact fastening surfaces 122 may be formed as spherical surfaces or cylindrical surfaces, for example, but such a shape may make manufacturing difficult and increase the manufacturing cost because the corresponding surfaces of the fasteners 160 also need to be formed in the same shape.

Nuts 162 and washers 164 are used as the fasteners 160. The nuts 162 are screw-coupled to a thread 152 formed on the outer peripheral surface of the connecting member 150. The washers 164 are installed to contact the surface-contact fastening surfaces 122 and are forced toward the surface-contact fastening surfaces 122 by the nuts 162. Flat washers are used as the washers 164 so as to conform to the planar surface-contact fastening surfaces 122.

In this embodiment, the connecting member fixing portions 120 is formed in a cap shape that is hemispherical in which one of the front and rear surfaces of the connecting member fixing portions 120 is convex, and the other thereof is concave. This is for the purpose of stably fixing the spiral blade 110. The hemispherical shape (cap shape) enables absorption of a shape error occurring when the same is manufactured by using FRP in such a hand lay-up method, for example, and facilitates the molding process. If necessary, the connecting member fixing portions 120 may be formed in triangular/quadrangular/pentagonal column shapes, instead of the cap shape, although many vortexes may occur due to the air flow, and the side surfaces of the connecting member fixing portions 120 between the surface-contact fastening surfaces 122 and the spiral surface 112a may be formed in changed shapes, such as curved surfaces or straight shapes, instead of the spherical shapes.

When the spiral blade 110 is fabricated by using FRP, the connecting member fixing portions 120 need to be formed in hemispherically round shapes in intaglio/relief, because the spiral blade 110 has a constant thickness. Surface-contact fastening surfaces 122 having planar surfaces are preferably formed on the connecting member fixing portions 120 formed in round shapes. Instead of the hemispherical shapes, the connecting member fixing portions 120 may be formed in elliptical shapes or in diamond shapes such that one side thereof or both sides thereof are convex. The same applies to the spiral blade 110 fabricated in an injection molding type (described later).

When the spiral blade 110 is fabricated by using FRP, the same may be formed in a hand lay-up method, which makes thickness adjustment or local shape change difficult. Accordingly, the hemispherical cap shape as illustrated in FIG. 1 to FIG. 6 is the most appropriate shape to overcome this problem.

Each connecting member fixing portion 120 in this embodiment is shaped such that the outer side thereof is high, and the height gradually decreases toward the center portion at which the rotating shaft 130 exists. If necessary, the connecting member fixing portions 120 may also be formed in polygonal (for example, triangular, quadrangular, or pentagonal) column shapes instead of the cap shapes, but much vortex may then occur due to the air flow. The shape or angle of the connecting member fixing portions 120 may be changed within a predetermined range.

Since the connecting member fixing portions 120 need to be able to secure stability related to fixing parts of the connecting member 150, the connecting member fixing portions 120 are required to be shaped so as to disperse stress resulting from fastening between the connecting member 150 having a thread 152 formed thereon and the nuts 162. If the shape of the spiral blade 110 is partially changed into an inappropriate shape in order to adjust only the angle of inclination for this reason, stress may concentrate, thereby posing a danger of fracture. If the shape is changed too widely, the aerodynamic characteristics may be affected. Accordingly, the connecting member fixing portions 120 preferably have the shapes as illustrated in the drawings according to the embodiments of the present invention, in order to disperse stress.

In general, when the spiral blade 110 is fabricated by using FRP, detailed adjustment is difficult due to shape errors, but, when fabricated in an injection molding type, the same can be easily formed through various adjustments such as thickness change for stress distribution, protrusion inclining, and the like.

When the spiral blade 110 is fabricated in an injection molding, the thickness of the spiral blade or a local shape can be formed by a mold such that a more stable shape can be designed through optimization.

In addition, the material characteristics are inferior in the case of injection molding that employs thermoplastic resin, compared with the case of FRP fabrication that employs thermosetting resin. However, when the injection molding is used, optimization can be done by reinforcing the thickness of the inside of the spiral blade, on which stress concentrates, and by reducing the thickness of other parts on which less stress concentrates. Moreover, the injection molding-type manufacturing enables mass production such that the manufacturing cost is reduced, and uniformity of the spiral blade is secured. Accordingly, the rotational balance of the final product is better than those manufactured by using FRP.

If necessary, the protruding direction of the connecting member fixing portions 120 may be changed to the opposite direction. In addition, the connecting member fixing portions 120 may be formed such that both the front and rear surfaces thereof are convex, but such formation requires multiple processes and consumes a large amount of materials.

The spiral plate portion 112 between two connecting member fixing portions 120 on both outside has at least a through-hole 120a formed therein such that a connecting member 150 passes through the same. The through-hole 120a is also formed along the leading edge of the spiral plate portion 112. The reason the through-hole 120a is formed in this manner is as follows: when connecting member fixing portions 120 coupled to both ends of the connecting member 150 are stably fixed, rigidity of the spiral blade 110 is secured to some extent, and the spiral blade 110 in the middle accordingly receives little force. In addition, the spiral surface 112a of the portion in which the through-hole 120a is formed is close to a planar surface that is almost parallel to a surface-contact fastening surface 122, and manufacturing processes in the factory can be reduced when FRP is used for manufacturing. Obviously, a connecting member fixing portion 120 may be formed on the portion in which the through-hole 120a is formed in a shape as described above.

Although it is assumed in this embodiment that three through-holes 120a are formed, only one through-hole 120a may be formed if necessary, and more connecting member fixing portions 120 may be formed instead of the through-holes 120a. Fasteners 160 are coupled to parts in which the through-holes 120a are formed.

Three spiral blades 110 according to the present invention, as described above, are preferably installed at a predetermined angular interval along the circumference of the rotating shaft 130, as illustrated in FIG. 5.

If necessary, two or four spiral blades 110 may be installed along the along the circumference of the rotating shaft 130.

Referring to FIG. 6, the spiral blade unit 100 according to the present invention includes a rotating shaft 130, three spiral blades 110, multiple connecting members 150, and multiple fasteners 160.

Respective spiral blades 110 have root portions 111 fixed to the rotating shaft 130 at a predetermined angular interval, and connecting members 150 are inserted into holes 121 of connecting member fixing portions 120, which are arranged on the same straight line, of respective spiral blades 110. In this state, the connecting members 150 are fixed to the spiral blades 110 through fasteners 160 on both the front and rear surfaces of the spiral blades 110.

In the present invention, fasteners 160 are coupled to connecting members 150 from the front and rear surfaces of at least two spiral blades 110, respectively, so as to fix the spiral blades 110 while maintaining surface contact with surface-contact fastening surfaces 122 of the connecting member fixing portions 120, which are arranged on the same straight line, such that the same do not move relative to the connecting members 150.

The spiral blades 110 are shaped such that the same are formed spirally along the circumference of the rotating shaft with varying angles with respect to the rotating shaft. Accordingly, there are three points of contact between the spiral blades 110 and the connecting members 150, which are configured straightly, in this embodiment. In addition, respective spiral blades 110 have different angles defined by the spiral surfaces 112a of the spiral blades 110 at respective contact points. As a result, the surface-contact fastening surfaces 122 of the connecting member fixing portions 120 need to be formed substantially perpendicularly to the connecting members 150.

In this regard, the surface-contact fastening surfaces 122 of the connecting member fixing portions 120, which are arranged on the same straight line, of respective spiral blades 110 are parallel to each other. Errors may occur during actual fabrication, but the error range is preferably about ±5°.

In addition, if necessary, a connecting member 150 may be inserted into a hole 121 of a connecting member fixing portion 120 of a spiral blade 110 and into a through-hole 120a of another spiral blade 110, and a fastener 160 may be coupled to the connecting member 150 such that multiple spiral blades 110 can be connected and fixed to each other through the connecting member 150.

Although FIG. 5 and FIG. 6 illustrate three spiral blades 110 installed on the rotating shaft 130, two or four spiral blades 110 may be installed around the rotating shaft 130 as needed. Five spiral blades 110 may be installed around the rotating shaft 130 in a special case. The same applies to spiral blade units according to embodiments described later.

As illustrated in FIG. 7 and FIG. 8, the connecting member 150 has a thread 152 formed on the outer peripheral surface thereof. The connecting member 150 is inserted into a hole 121. The fastener 160 includes nuts 162 coupled to the thread 152 formed on the outer peripheral surface of the connecting member 150 and washers 164 coupled to the outer peripheral surface of the connecting member 150 on the front and rear surfaces of the spiral blade 110, respectively. The washers 164 on both the front and rear surfaces are pressurized by the nuts 162, respectively, while making surface contact with a surface-contact fastening surface 122, thereby holding the surface-contacting fastening surface 122.

FIG. 9 is an enlarged perspective view illustrating another example of the spiral blade according to the present invention. FIG. 10 is an enlarged perspective view of the spiral blade illustrated in FIG. 9, seen from the rear surface. FIG. 11 is an enlarged perspective view of the spiral blade illustrated in FIG. 9, seen from the front surface. FIG. 12 is an enlarged view of an example of the connecting member fixing portion, and FIG. 13 is an enlarged view of another example of the connecting member fixing portion. FIG. 14 is a side view of a spiral blade unit according to the present invention, wherein the spiral blades illustrated in FIG. 9 are coupled through partial shaft portions. FIG. 15 is a side view of a spiral blade unit according to the present invention, wherein spiral blades are connected by using multiple connecting members and fasteners.

The spiral blade 110 illustrated in FIG. 9 to FIG. 15 has three connecting member fixing portions 120 formed at an interval along the leading edge of the spiral plate portion 112. The connecting member fixing portions 120 in this embodiment have different shapes depending on the position of installation, but all are formed convexly on both the front and rear surfaces. The connecting member fixing portions 120 formed on both outsides of the leading edge have the same shape and are arranged on both the front and rear surfaces of the spiral blade 110 in opposite directions. The connecting member fixing portion 120 formed in the middle between both ends protrudes to a smaller height than the connecting member fixing portions 120 on both ends, and has the shape of a cylinder having a hole 121 formed therein.

Referring to FIG. 9 to FIG. 15, even connecting member fixing portions 120 formed on the same spiral blade 110 are preferably formed in different shapes depending on the position. A connecting member fixing portion 120 positioned away from the rotating shaft 130 has the shape of a cylinder which has a hole 121 therein, and which is cut in a diagonal direction, as illustrated in FIG. 12. A connecting member fixing portion 120 positioned close to the rotating shaft 130 has an elliptical shape elongated in the circumferential direction, as illustrated in FIG. 13, compared with the connecting member fixing portion 120 positioned away from the rotating shaft 130. The other part than the surface-contact fastening surface 122 has a curved shape, but may have such a shape that multiple planes meet at an angle. Obviously, the elliptical shape may be replaced with a diamond shape.

In addition, the connecting member fixing portion 120 is preferably arranged to be elongated in the circumferential direction, not in the radial direction, and to be inclined in the circumferential direction. This can minimize air resistance caused by the connecting member fixing portions 120 when the spiral blade unit 100 rotates.

The connecting member fixing portions 120 have surface-contact fastening surfaces 122 formed on end surface portions of both convex ends thereof, respectively. The surface-contact fastening surfaces 122 are preferably formed to be planar.

The spiral blade 110 illustrated in FIG. 9 to FIG. 11 has a partial shaft portion 131 formed integrally along the root portion 111. The partial shaft portion 131, which constitutes a part of the rotating shaft 130, is coupled to a partial shaft portion 131 of another spiral blade 110, as illustrated in FIG. 14 and FIG. 15, such that a spiral blade unit 100 can be fabricated easily.

As is clear from FIG. 9 to FIG. 11, the root portion 111 of the spiral blade 110 has ribs 115 formed thereon at an interval. The ribs 115 are for the purpose of connecting the root portion 111 to the partial shaft portion 131 more firmly.

The above-mentioned spiral blade 110 is preferably formed through injection molding by using molds. Injection molding of the spiral blade 110 makes it possible to variously form the shape of the connecting member fixing portions 120 described above, and to vary the thickness of the spiral plate portion 112 in the radial direction.

Referring to FIG. 14 and FIG. 15, while connecting members 150 are inserted into holes 121 of connecting member fixing portions 120, which are arranged on the same straight line, of respective spiral blades 110, nuts 162 constituting fasteners 160 are coupled to the connecting members 150 from the front and rear surfaces of the spiral blades 110 with washers 164 interposed between the same and surface-contact fastening surfaces 122, respectively. The fasteners 160 maintain surface contact with the surface-contact fastening surfaces 122 of the connecting member fixing portions 120, which are arranged on the same straight line, so as to fix the spiral blades 110 such that the same do not move with regard to the connecting members 150.

In this regard, the surface-contact fastening surfaces 122 of the connecting member fixing portions 120, which are arranged on the same straight line, of respective spiral blades 110 are preferably parallel to each other, but errors may occur during actual fabrication. The error range is preferably about±5°

The others are the same as described with reference to FIG. 1 to FIG. 6.

FIG. 16 is a perspective view illustrating a variant example of the spiral blade illustrated in FIG. 9.

If necessary, the root portion 111 of the spiral blade 110 may have a hole 117 in a part thereof which contacts the partial shaft portion 131. The hole 117 is for the purpose of integrally binding partial shaft portions 131 of multiple spiral blades 110 by a band, for example. Two or more holes 117 may be formed at an interval.

The others are the same as described with reference to FIG. 9 to FIG. 13.

FIG. 17 illustrates another example of the connecting member fixing portion, and FIG. 18 illustrates still another example of the connecting member fixing portion.

If necessary, the connecting member fixing portion 120 of the spiral blade 110 described with reference to FIG. 1 to FIG. 6 may be configured in an elliptical shape or a diamond shape such that the same is elongated in the longitudinal direction, not in the radial direction, and is inclined in the circumferential direction, as illustrated in FIG. 17 and FIG. 18.

The others are the same as described above.

FIG. 19 is an enlarged perspective view illustrating another example of the spiral blade according to the present invention. FIG. 20 is an enlarged front view of the spiral blade illustrated in FIG. 19. FIG. 21 is a perspective view of a spiral blade unit obtained by assembling three spiral blades illustrated in FIG. 19 and a non-circular section shaft member. FIG. 22 is a front view of the spiral blade unit illustrated in FIG. 21.

The spiral blade 110 illustrated in FIG. 19 and FIG. 20 has a partial shaft portion 131 formed integrally along the root portion 111 of the spiral plate portion 112 so as to constitute a part of the rotating shaft 130. The range of angle at which the root portion 111 of the spiral plate portion 112 is connected along the outer peripheral surface of the partial shaft portion 131 is changed from a 360° range to a 300° range.

This embodiment illustrates an inflection connecting portion 114 formed on the leading edge side of the spiral plate portion 112 such that the same is bent toward the center of the rotating shaft 130 from a spiral shape and connected to the partial shaft portion 131, in order to reduce the range of angle formed by connecting the root portion 111 of the spiral plate portion 112 to the outer peripheral surface of the partial shaft portion 131. As is clear from FIG. 19 to FIG. 21, the spiral plate portion 112 extends from the outer periphery to the inside spirally around the partial shaft portion 131 and is then integrally connected to the partial shaft portion 131 through the inflection connecting portion 114, which is configured as a flat plate arranged toward the center of the rotating shaft 130, preferably near the partial shaft portion 131. In this embodiment, the inflection connecting portion 114 has a triangular shape. A reinforcement portion 116 is formed such that the thickness of the part having a changing curvature is larger than the thickness of the peripheral portion, thereby reinforcing the strength.

In this embodiment, the range of angle at which the spiral plate portion 112 is connected around the surface of the partial shaft portion 131 is 300°, for example. However, the minimum range of angle at which the spiral plate portion 112 is connected around the surface of the partial shaft portion 131 is preferably equal to or larger than a 240° range, and the maximum range of angle thereof is preferably equal to or smaller than a 350° range. If the range of angle is smaller than 240°, the reduced area of the spiral plate portion substantially degrades the power generation efficiency and, if the range of angle is larger than 350°, many undercuts occur during injection molding.

Preferably, the range of angle at which the spiral plate portion 112 is connected around the surface of the partial shaft portion 131 increases/decrease within about 30° with regard to the 300° range illustrated in FIG. 19. In other words, the range of angle is preferably equal to or larger than a 240° range and is preferably equal to or smaller than a 330° range.

In this embodiment, the partial shaft portion 131 is formed in an angular range of 120° such that three spiral blades 110 and a non-circular section shaft member 130a are coupled, thereby forming a spiral blade unit 100 as illustrated in FIG. 21 and FIG. 22.

As illustrated, the partial shaft portion 131 has a non-circular section groove 132 formed near the center portion of the rotating shaft 130. The non-circular section groove 132, to which the non-circular section shaft member 130a is coupled as illustrated in FIG. 21 and FIG. 22, is for the purpose of preventing the non-circular section shaft member 130a from rotating relative to the spiral blade 110. The shape of the partial shaft portion 131 having such a non-circular section groove 132 will be described later in more detail with reference to FIG. 23A to FIG. 23F.

When three spiral blades 110 are coupled to each other through the partial shaft portion 131, a regular hexagonal hole is formed at the center portion by V-shaped non-circular section grooves 132, and a hexagonal section portion of a non-circular section shaft member 130a is coupled thereto as illustrated in FIG. 21 and FIG. 22, thereby constituting a spiral blade unit 100 according to the present invention.

FIGS. 23A to 23F are side perspective views of the spiral blade illustrated in FIG. 19, which is rotated sequentially by 60 degrees.

As illustrated in FIG. 23A to FIG. 23F, the partial shaft portion 131 has a non-circular section groove 132 formed near the center portion of the rotating shaft 130. The non-circular section groove 132, to which the non-circular section shaft member 130a is coupled as illustrated in FIG. 21 and FIG. 22, is for the purpose of preventing the non-circular section shaft member 130a from rotating relative to the spiral blade 110.

In this embodiment, the non-circular section groove 132 constitutes a V-shaped groove, which has an angle of 120° between inner peripheral surfaces thereof. The outer peripheral surface of the partial shaft portion 131 has a straight portion 131a arranged straightly along the longitudinal direction of the partial shaft portion 131, and a twist portion 131b that is twisted in one direction. The interaction between the straight portion 131a and the twist portion 131b ensures that three partial shaft portions 131 remain firmly coupled to each other with uncoupling. The straight portion 131a is preferably formed to have a length corresponding to at least half the length of partial shaft portions 131 coupled to each other, and the twist portion 131b is preferably formed to have a length smaller than half the length thereof. The appropriate twisting angle of the twist portion 131b with regard to the straight portion 131a is about 180°. The twisting angle is preferably within the range of 150-230°, and is more preferably within the range of 150-210°.

When three spiral blades 110 are coupled to each other through three partial shaft portions 131, a regular hexagonal hole is formed at the center portion by V-shaped non-circular section grooves 132, and the hexagonal section portion, which is arranged straightly, of the non-circular section shaft described above may be coupled thereto.

Obviously, the non-circular section grooves 132 and the non-circular section shaft member 130a may also be formed to have parts twisted in one direction, if necessary, as in the case of the outer peripheral surface of the partial shaft portions 131.

The others are the same as described above.

If necessary, non-circular section grooves 132 may be formed at 60° on the inner surface of partial shaft portions 131 as illustrated in FIG. 24 such that a regular triangular hole is formed when three partial shaft portions 131 are coupled to each other, and a non-circular section shaft member 130a having a triangular section may be coupled to the hole.

The triangular corner portions of the non-circular section grooves 132 and the non-circular section shaft member 130a are preferably rounded as illustrated in FIG. 25.

Although embodiments have been illustrated and described above assuming that three spiral blades are coupled so as to constitute a spiral blade unit, two spiral blades having partial shaft portions formed at 180° may be coupled to each other through the partial shaft portions, if necessary, so as to constitute a spiral blade unit. In addition, four spiral blades 110 having partial shaft portions formed at 90° may be coupled to each other through the partial shaft portions, if necessary, so as to constitute a spiral blade unit.

The present invention is applicable to manufacturing a spiral blade appropriate for wind power generation and a spiral blade unit having such a spiral blade. The spiral blade unit according to the present invention is also applicable to hydroelectric power generation, depending on the case.

Claims

A spiral blade having a root portion fixed to a rotating shaft and a spiral plate portion formed spirally so as to be positioned away from the root portion in a radial direction of the rotating shaft such that rotational power can be obtained from a fluid flowing in a longitudinal direction of the rotating shaft, the spiral plate portion having a spiral surface formed thereon, the spiral blade comprising;

a partial shaft portion formed integrally along the root portion so as to constitute a part of the rotating shaft,

wherein a range of angle at which the root portion of the spiral plate portion is connected around an outer peripheral surface of the partial shaft portion is equal to or larger than a 240° range and is equal to or smaller than a 350° range.
The spiral blade of claim 1, wherein the range of angle at which the root portion of the spiral plate portion is connected around the outer peripheral surface of the partial shaft portion is equal to or larger than a 270° range and is equal to or smaller than a 330° range.
The spiral blade of claim 1, wherein an inflection connecting portion is formed on a leading edge side of the spiral plate portion so as to be bent from a spiral shape toward a center of the rotating shaft and to be connected to the partial shaft portion such that the range of angle at which the root portion of the spiral plate portion is connected to the outer peripheral surface of the partial shaft portion is reduced.
The spiral blade of claim 1, wherein the partial shaft portion has a non-circular section groove formed near a center portion of the rotating shaft, and the outer peripheral surface of the partial shaft portion has a straight portion and a twist portion along the longitudinal direction of the partial shaft portion.
The spiral blade of claim 1, wherein the spiral blade comprises multiple connecting member fixing portions arranged at an interval along a leading edge of the spiral plate portion and formed integrally with the spiral plate portion so as to protrude from the spiral surface toward at least one of front and rear directions; holes are bored in protruding parts of the connecting member fixing portions such that a connecting member passes therethrough; and the connecting member fixing portions have surface-contact fastening surfaces formed thereon such that fasteners can be fixed to the connecting member while making surface contact with the front and rear surfaces around the holes.
The spiral blade of claim 5, wherein the surface-contact fastening surfaces comprise planar surfaces or spherical surfaces, and a hole is formed in a leading edge of the spiral plate portion between the connecting member fixing portions arranged at an interval such that the connecting member passes therethrough.
The spiral blade of claim 5, wherein the connecting member fixing portions are formed in cap shapes such that one of the front and rear surfaces thereof is convex and the other thereof is concave, or both the front and rear surfaces thereof are convex, have identical shapes, and are arranged in opposite directions.
The spiral blade of claim 5, wherein the connecting member fixing portions are arranged so as to be elongated in the circumferential direction, instead of in the radial direction, and to be inclined in the circumferential direction.
The spiral blade of claim 1, wherein a hole is formed in at least one part between both ends of the root portion such that a band passes therethrough so as to bind partial shaft portions of multiple spiral blades.
The spiral blade of claim 4, wherein the partial shaft portion is formed in a 120° angle range in a shape obtained by equally dividing the rotating shaft into three, and the non-circular section groove is a V-shaped non-circular section groove having an angle of 120° between inner peripheral surfaces thereof.
A spiral blade unit comprising at least two spiral blades of one of claims 1 to 10, which are coupled to each other through partial shaft portions.
The spiral blade unit of claim 11, comprising:

A connecting member inserted into holes of connecting member fixing portions, which are arranged on a same straight line, of the at least two spiral blades; and

multiple fasteners coupled to the connecting member from front and rear surfaces of the at least two spiral blades, respectively, and configured to maintain surface contact with surface-contact fastening surfaces of the connecting member fixing portions arranged on the same straight line such that the spiral blades are fixed and prevented from moving with regard to the connecting member.
The spiral blade unit of claim 12, wherein the three spiral blades are configured to be coupled to each other through the partial shaft portions, and the surface-contact fastening portions arranged on the same straight line are arranged in parallel to each other.
The spiral blade unit of claim 12, wherein the fasteners comprise washers coupled to outer peripheral surfaces of the connecting members, and nuts coupled to threads formed on the connecting members so as to pressurize the washers toward the surface-contact fastening surfaces.
The spiral blade unit of claim 11, wherein a non-circular section hole is formed inside the partial shaft portions coupled to each other, and a non-circular section shaft member is coupled to the non-circular section hole.