Monopole tower and wind turbine generator having monopole tower

The present invention provides a monopole tower having a tower supporting structure in which the outer dimension of a tower shell is the maximum dimension by eliminating a base plate which extends toward the outside of the tower shell. In a monopole tower provided upright on a foundation B, a lower end side of the tower 2 comprised a tower-side coupling member in a range equal to or less than outside diameter of a tower shell 21. In a space comprising a foundation-side coupling member provided on the foundation B, the foundation-side coupling member and the tower-side coupling member are coupled by welding, a bolt using a splice plate, or a rivet.

TECHNICAL FIELD

The present invention relates to a monopole tower and a wind turbine generator having a monopole tower (support).

BACKGROUND ART

In a wind turbine generator, a rotor head having wind turbine blades receives wind force and rotates, the rotation is increased by a speed-up gear, and power is generated by a power generator which is driven by the increased rotation.

The rotor head is mounted on a tower for a wind turbine (hereinbelow, called “tower”), attached to an end of a nacelle which can yaw, and supported so as to be rotatable about the rotary axis in an substantially horizontal direction.

Generally, the tower for a wind turbine often employs a monopole type made of steel using a cylindrical shell, and has a structure that a base plate provided at the lower end of the tower shell is fixed to a foundation made of reinforced concrete by an anchor bolt.

FIGS. 11 and 12show a conventional tower supporting structure. At the lower end of a tower2, a flange-shaped base plate22projected in the horizontal direction from both inner and outer faces of a tower shell21is provided. The base plate22is a member for coupling and fixing the tower2to a foundation B via a number of anchor bolts10whose lower ends are embedded in the foundation B. In the configuration example shown in the diagram, two lines of anchor bolts10are disposed on a concentric circle on the outer peripheral side and the inner peripheral side of the cylindrical-shaped tower shell21. By screwing a nut11on the upper end side of each of the anchor bolts10penetrating bolt holes22ain the base plate22, fixing is performed. Reference numeral12denotes a layer of grout formed on the concrete of the foundation B.

In a joint structure of a steel column and a steel joist, a method of easily obtaining a clearance with a fixing bracket by slightly moving the joist without requiring subtle crane operation, auxiliary heavy machine, and the like for adjustment is proposed. In the joint structure, both of the fixing bracket for the steel column and the steel joist are cut in a form that they are open to a plumbing side, and a splice plate is attached and fastened with a high-strength bolt, thereby constructing the joint (refer to, for example, patent citation 1).Patent Citation 1: Japanese Unexamined Patent Application, Publication No. Hei 7-207833

The conventional tower supporting structure has a higher effect by disposing the anchor bolt10on the outside of the tower shell21, so that the base flange often extends toward the outside of the tower shell21. Further, since the shell member made of steel and having the cylindrical shape is a main strength member, the larger the outside diameter of the tower shell21is, the higher a section efficiency is. The monopole tower made of steel is therefore demanded to increase the outside diameter of the shell as much as possible within the range in which the weight can be reduced.

On the other hand, external dimensions of the tower2have to satisfy constraint conditions at the time of transportation and the like. In the case of the monopole, the tower2is divided into a plurality of sections in the height direction, and the sections are transported. A tower section of a base portion is transported in a state where the base plate22is welded and integrated with the tower shell21. Consequently, the outside diameter of the base plate22extended toward the outside of the tower shell21becomes the maximum outside diameter of the tower2. Consequently, it is difficult to increase the outside diameter of the tower shell21to the constraint condition.

DISCLOSURE OF INVENTION

The present invention has been achieved in view of the above circumstances and an object of the invention is to provide a wind turbine power generator having a tower supporting structure in which the outside diameter of the tower shell becomes the maximum diameter by eliminating the base plate extended toward the outside of the tower shell.

In order to solve above mentioned problems, following means are adopted.

In accordance with one aspect of the present invention, there is provided a monopole tower provided upright on a foundation, wherein a lower end of the tower has a tower-side coupling member in a range of an outside diameter of a tower shell or less and, in a space having a foundation-side coupling member provided for the foundation, the foundation-side coupling member and the tower-side coupling member are coupled to each other by welding, a bolt using a splice plate, or a rivet.

In the monopole tower provided as the above aspect of the invention, the lower end of the tower has the tower-side coupling member in the range of the outside diameter of the tower shell or less and, in the space having the foundation-side coupling member provided for the foundation, the foundation-side coupling member and the tower-side coupling member are coupled to each other by welding, the bolt using the splice plate, or the rivet. Therefore, there is no member such as a base plate larger than the outside diameter of the tower shell, and as a result, the outside diameter of the tower shell can be increased to the constraint condition, and the section efficiency can be improved. That is, as the maximum outside diameter of the tower, the outside diameter of the tower shell can be used.

In the above aspect, the lower end side of the tower may have a double-pipe structure made by a tower shell and an inner cylinder, and the inner cylinder extended toward the inside of the foundation and the tower-side coupling member may be inserted in the space.

In accordance with another aspect of the present invention, there is provided a monopole tower provided upright on a foundation made of reinforced concrete, wherein a foundation coupling part is formed on a lower end side of the tower, the foundation coupling part comprising: a diaphragm mounted vicinity of a lower end on the inside of the tower; an inner cylinder coupled to the under face of the diaphragm and extending downward in a tower shell to the inside of the foundation; a bottom plate attached to the lower end of the inner cylinder and having a diameter substantially the same as the outside diameter of the tower shell; tower-side brackets coupled to the inner face of the tower shell, the under face of the diaphragm, an outer face of the inner cylinder, and a top face of the bottom plate and disposed radially from the outer peripheral face of the inner cylinder in a range of an outside diameter of the tower shell or less; and a ring diaphragm coupling the lower end of the tower shell, the outer peripheral face of the inner cylinder, and the tower-side brackets, a tower coupling space is formed in a center portion of the foundation, the tower coupling space comprising: a foundation space to which the foundation coupling part is inserted, and a foundation-side bracket disposed on an extension line of the tower-side bracket so as to be coupled and fixed to the tower-side bracket, and exposed to the foundation space is formed, the foundation coupling part is inserted in the tower coupling space, and between the coupling members on the foundation coupling part side and the foundation-side brackets are coupled via a splice plate or welding.

In the monopole tower provided as another aspect of the invention, a foundation coupling part is formed on a lower end side of the tower. The foundation coupling part comprises: a diaphragm mounted vicinity of a lower end on the inside of the tower; an inner cylinder coupled to the under face of the diaphragm and extending downward in a tower shell to the inside of the foundation; a bottom plate attached to the lower end of the inner cylinder and having a diameter substantially the same as the outside diameter of the tower shell; tower-side brackets coupled to the inner face of the tower shell, the under face of the diaphragm, an outer face of the inner cylinder, and a top face of the bottom plate and disposed radially from the outer peripheral face of the inner cylinder in a range of an outside diameter of the tower shell or less; and a ring diaphragm coupling the lower end of the tower shell, the outer peripheral face of the inner cylinder, and the tower-side brackets. A tower coupling space is formed in center portion of the foundation, the tower coupling space comprises: a foundation space to which the foundation coupling part is inserted, and a foundation-side bracket disposed on an extension line of the tower-side bracket so as to be coupled and fixed to the tower-side bracket, and exposed to the foundation space is formed. The foundation coupling part is inserted in the tower coupling space, and between the coupling members on the foundation coupling part side and the foundation-side brackets are coupled via a splice plate or welding. Consequently, there is no member like the base plate larger than the outside diameter of the tower shell. Therefore, the outside diameter of the tower shell can be increased to the constraint condition, and the section efficiency can be improved. That is, as the maximum outside diameter of the tower, the outside diameter of the tower shell can be used.

In the monopole tower, preferably, the foundation-side bracket has an I shape in cross section provided with flanges at its top and bottom and, between a vertical walls of the tower-side bracket and the foundation-side bracket, the ring diaphragm and the flange, and the bottom plate and the flange are coupled via the splice plate and the bolts and nuts. With the configuration, the coupling strength between the tower and the foundation can be further improved.

In the invention, preferably, the diaphragm positioned vicinity of the lower end of the tower is positioned vicinity of the lower side of a door opening provided for the tower shell. With the configuration, the diaphragm can also serve as the floor provided for the entrance to the inside of the tower.

In the invention, preferably, the inner cylinder has a circular truncated cone shape whose upper end on the large diameter side is coupled to the tower shell. With the configuration, stress transfer from the tower shell toward the inner cylinder becomes smooth and, therefore, stress transfer from the tower to the foundation becomes also smooth.

In the invention, preferably, after coupling coupling members on the foundation coupling part side and the foundation-side brackets, the tower coupling space is filled with concrete.

A wind turbine generator as still another aspect of the invention has the monopole tower according to any of the aspects of the invention.

Since such a wind turbine generator has the monopole tower, the outside diameter of the tower shell can be used as the maximum outside diameter of the tower.

In the monopole tower and the wind turbine generator of the invention, the outside diameter of the tower shell can be used as the maximum diameter of the tower. In other words, a member projecting to the outside of the tower shell like the base plate becomes unnecessary. Thus, the outside diameter of the tower shell is maximized, and the section efficiency is improved. In addition, the tower supporting structure having the outside diameter as large as possible in the range of the constraints such as transport limitation. That is, by employing the tower supporting structure of the present invention, the wind turbine generator having the monopole tower can use the outside diameter of the tower shell as the maximum diameter.

As a result, for the tower which becomes more expensive and, moreover, in which the loading condition becomes stricter as the size of the wind turbine generator increases, the wind turbine generator having the tower supporting structure facilitating realization of both satisfaction of the constraint condition such as transport limitation and assurance of necessary strength is obtained.

Further, an inexpensive roll steel plate can be used for the brackets, the splice plates, and the like and, in addition, the expensive base flange and the anchor bolts become unnecessary, so that the cost of the wind turbine generator can be reduced. Further, the anchor bolts are not used, so that maintenance such as refastening is also unnecessary.

EXPLANATION OF REFERENCE

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of a tower supporting structure of a wind turbine generator according to the present invention will be described below with reference to the drawings. A wind turbine generator1of an upwind type shown inFIG. 6has a tower2for a wind turbine (hereinbelow, called “tower”) provided upright on a foundation B, a nacelle3mounted on the upper end of the tower2, and a rotor head4supported so as to be rotatable about the rotary axis in an substantially horizontal direction and provided at one end of the nacelle3.

To the rotor head4, a plurality of (for example, three) wind turbine blades5are attached radially about the rotary axis of the rotor head4. With the configuration, the force of wind hit by the wind turbine blades5from the rotary axis direction of the rotor head4is converted to power that rotates the rotor head4about the rotary axis direction.

In proper places in the outer peripheral surface (for example, an upper part) of the nacelle3, an anemometer that measures a wind speed value of the periphery, an anemoscope that measures wind direction, and the like are mounted.

Specifically, the wind turbine generator1generates power by driving a power generator (not shown) with the rotor head4receiving wind force by its wind turbine blades5and rotating about the rotary axis which is substantially horizontal direction is mounted in the nacelle3. The nacelle3is mounted on the upper end of the tower2which is provided upright on the foundation B made of reinforced concrete and supported so as to yaw. In this case, the tower2is of the monopole type made of steel. By connecting flanges (not shown) provided at ends of a plurality of tower sections obtained by dividing the tower2in the height direction, a cylindrical tower assuring necessary length (height) is obtained.

First Embodiment

A tower supporting structure for supporting the tower2upright on the foundation B will be described below with reference toFIGS. 1A to 6.

In the tower supporting structure shown in the diagram, a foundation coupling part30is formed on the lower end side of the tower2. The foundation coupling part30is inserted in a tower coupling space50which is not yet filled with concrete and is preliminarily formed in the center of the foundation B to support the tower2upright.

In the foundation coupling part30inserted in the tower coupling space50, a coupling member on the side of the foundation coupling part30which will be described later and a foundation-side bracket51provided as a coupling member in the tower coupling space50are coupled to each other via a splice plate60and bolts and nuts70. After that, the space in the tower coupling space50is filled with concrete, and the concrete is solidified, thereby completing mounting of the tower2.

The above-described foundation coupling part30has: a diaphragm31mounted in the position vicinity of the lower end on the inside of the tower2; an inner cylinder32coupled to the under face of the diaphragm31and extending downward in a tower shell21to the inside of the foundation B; a bottom plate33attached to the lower end of the inner cylinder32and having the diameter same as the outside diameter of the tower shell21; a ring diaphragm34coupling the lower end of the tower shell21and the outer peripheral face of the inner cylinder32; and a plurality of tower-side brackets35coupled to the under face of the diaphragm31, the inner face of the tower shell21, the outer face of the inner cylinder32, divided faces in the circumferential direction of the ring diaphragm34and the top face of the bottom plate33and disposed radially from the outer peripheral face of the inner cylinder32.

The diaphragm31is a circular plate member having the diameter same as the inside diameter of the tower2. The diaphragm31is attached by being welded to the inside wall of the tower shell21so as to vertically divide the internal space of the tower2.

The diaphragm31is attached in a position vicinity of the lower end of the tower2slightly lower than a door opening6provided for the tower shell21, that is, vicinity of the lower side of the door opening6provided for the tower shell21, and is also used as an inner floor material of the tower2.

The door opening6is provided so that a worker enters the tower2at the time of construction, maintenance, and the like, and is provided with an openable door.

The inner cylinder32is a concentric cylindrical member disposed in the internal space of the tower shell21, and the upper end of the cylinder is welded to the under face of the diaphragm31. The lower end of the cylinder32is lower than the lower end of the tower shell21and enters the foundation B in a predetermined mounting position.

The bottom plate33is a plate member having a circular or polygonal shape welded to the lower end of the inner cylinder32. The bottom plate33has a diameter substantially the same as the outside diameter of the tower shell21. After concrete is filled and solidified, the bottom plate33is supported on a concrete mounting face formed in the tower coupling space50. The bottom plate33is also used as a coupling member on the foundation coupling part30side.

The ring diaphragm34is an annular plate member coupling the lower end of the tower shell21, the outer peripheral surface of the inner cylinder32, and the side face of the tower-side brackets35. The ring diaphragm34is divided in the circumferential direction in the position of the tower-side brackets35, that is, in a circular arc shape. The inner peripheral end is welded to the outer peripheral surface of the inner cylinder32, the outer peripheral end is welded to the lower end of the tower shell21, and a divided face in the circumferential direction is welded to the side face of the tower-side bracket35.

The tower-side bracket35is a rectangular plate member welded to the outer surface of the inner cylinder32, the inner face of the tower shell21, the bottom face of the diaphragm31, and the top face of the bottom plate33. A plurality of tower-side brackets35are disposed radially from the outer peripheral surface of the inner cylinder32to the outside diameter of the tower shell21. In a configuration example shown in the diagram, eight tower-side brackets35are attached radially at pitches of 45 degrees in the circumferential direction from the outer peripheral surface of the inner cylinder32. The tower-side bracket35is a member used as a main coupling member on the foundation coupling part30side.

The number of tower-side brackets35can be changed properly according to conditions and, therefore, is not limited to eight.

The tower coupling space50is formed in a center portion in the foundation B. The tower coupling space50when concrete is not filled is a foundation space52. The foundation-side brackets51integrated with the foundation B are exposed to the foundation space52. As the foundation-side bracket51, for example, as shown inFIG. 5, a member having an I shape in cross section provided with flanges51aand51bat its top and bottom is employed.

The foundation-side bracket51in this case is disposed on the extension line of the tower-side bracket35so as to be connected to the tower-side bracket35. Specifically, the foundation-side brackets51are radially attached at pitches of 45 degrees in the circumferential direction so as to be connected to the eight tower-side brackets35disposed radially in predetermined tower mounting positions. As a result, in the predetermined tower mounting positions, the tower-side brackets35and the foundation-side brackets51exist on the same straight lines disposed radially.

At the time of mounting the tower2in the foundation B and fixing it, the foundation coupling part30is inserted in the tower coupling space50, and the tower-side bracket35as a coupling member on the side of the foundation coupling part30, the bottom plate33, the ring diaphragm34, and the foundation-side bracket51are coupled by using splice plates60and bolts and nuts70.

The splice plate60is a plate member disposed over the coupling member on the side of the foundation coupling part30and the coupling member on the side of the tower coupling space50. The splice plates60are disposed on both sides so as to sandwich the coupling members from both faces. By fastening the three members with a number of bolts and nuts70penetrating the coupling members and the splice plates60disposed on both faces, the coupling members of the foundation coupling part30and the tower coupling space50are coupled to each other firmly.

For coupling of the tower-side bracket35as a coupling member on the foundation coupling part30side, the bottom plate33, the ring diaphragm34, and the foundation-side bracket51, a configuration of friction joint using high-strength bolts and nuts as the bolts and nuts in the above-described manner, a configuration using rivets, or a configuration of welding without using the splice plates and bolts and nuts can be properly selected.

FIG. 4Ais an enlarged diagram of the portion C inFIG. 1A. The flange51aprovided on the foundation-side bracket51and the tower-side ring diaphragm34are sandwiched by two upper and lower splice plates60, and the three plate members are fastened by a number of bolts and nuts70. To make the splice plates60penetrate the tower2, through holes23are formed in the tower shell21.

FIG. 4Bis an enlarged diagram of the portion D inFIG. 1A. The flange51bprovided below the foundation-side bracket51and the tower-side bottom plate33are sandwiched by two upper and lower splice plates60, and the three plate members are fastened by a number of bolts and nuts70.

FIG. 5is a cross section taken along line E-E ofFIG. 2. The upper and lower flanges51aand51bprovided for the foundation-side bracket51having the I shape in section are coupled to the ring diaphragm34and the bottom plate33, respectively, by the splice plates60and the bolts and nuts70on both sides coupling the vertical walls. In this case, the coupling part between the vertical walls is a part where the tower-side bracket35and the foundation-side bracket51disposed in the vertical direction are coupled with the splice plates60and the bolts and nuts70.

As described above, with the I-shape section obtained by providing the foundation-side bracket51with the upper and lower flanges51aand51b, in addition to the vertical walls of the tower-side bracket35and the foundation-side bracket51, the ring diaphragm34, the bottom plate33, and the flanges51aand51bcan be coupled by the splice plates60and the bolts and nuts70. As a result, the foundation coupling part30and the foundation B are coupled firmly in both of the vertical and horizontal directions, so that the coupling strength between the tower2and the foundation B can be further improved.

After coupling the coupling member on the foundation coupling part30side and the foundation-side bracket51of the tower coupling space50as described above, the tower coupling space50is filled with concrete. When the concrete in the tower coupling space50is solidified, a tower supporting structure that makes the tower2stand upright on the foundation B is completed. In the case of making the tower2stand upright on the foundation B, it is sufficient to provide the lowest tower section provided with the foundation coupling part30upright on the foundation B, sequentially couple upper tower sections, and complete the monopole tower2having necessary height.

The tower supporting structure constructed as described above does not need the base plate22having the largest outside diameter in the conventional structure, so that there is no member larger than the outside diameter of the tower shell21. Therefore, the tower2can be designed so that the outside diameter of the tower shell21satisfies constraints such as transport limitation. The outside diameter of the tower shell21can be increased to the constraint condition, and the section efficiency can be improved. That is, as the maximum outside diameter of the tower2, the outside diameter of the tower shell21can be used. To improve welding workability, it may be also considered to make the outside diameter of the ring diaphragm34slightly larger than that of the tower shell21.

The lower end of the tower2has a double-pipe structure made by the tower shell21and the inner cylinder32in a region lower than the diaphragm31. Consequently, strength of the lower end side as the root of the tower2increases, and the thickness of the tower shell21can be reduced by the double structure.

Further, by setting the diaphragm31vicinity of the lower side of the door opening6, the diaphragm31can be also used as the inner floor member of the tower2.

In the foregoing embodiment, by providing the through holes23in the tower shell21, the ring diaphragm34and the flange51aare coupled by the slice plates60penetrating the tower shell21. For example, like a modification as shown inFIGS. 7 and 8, a structure of coupling the ring diaphragm34and the flange51aonly by a lower splice plate without providing the through holes23may be also employed.

The tower supporting structure having such a foundation coupling part30A makes the coupling strength of the flange51aslightly weaker. However, there is also an advantage such that man hour and material cost required for the work can be reduced. The structure can be therefore properly selected according to the height of the tower2, loading conditions of the nacelle3, and the like.

Second Embodiment

A second embodiment of the tower supporting structure in which the tower2is provided upright on the foundation B will now be described with reference toFIGS. 9 and 10. The same reference numerals are designated to parts similar to those of the foregoing embodiment and their detailed description will not be repeated.

The second embodiment relates to a foundation coupling part30B employing an inner cylinder32A having a circular truncated cone shape whose upper end on the larger diameter side is coupled to the tower shell21. That is, the inner cylinder32A of the embodiment has a structure that the upper end having a large diameter is directly welded to the inner wall of the tower shell21, and the lower end having a small diameter is welded to the bottom plate33.

Consequently, stress transfer from the tower shell21to the inner cylinder32A is direct and smooth different from that in the cylinder shape in which stress is transferred via the diaphragm31. Therefore, stress transfer from the tower2to the foundation B becomes also smooth.

According to the foregoing embodiments of the invention, for the lower end side of the tower2, the foundation coupling part30,30A, or30B of the double-pipe structure made by the tower shell21and the cylindrical shaped inner cylinder32(or the inner cylinder32A) which are concentric is provided.

In the double-pipe structure, by extending the inner cylinder32or32A toward the inside of the foundation B, the inner cylinder32or32A becomes long downward from the tower shell21. At the time of providing the tower2upright on the foundation B, the extended part of the inner cylinder32,32A and the tower-side coupling members (the tower-side bracket35, the ring diaphragm34, and the bottom plate33) provided in the range of the outside diameter of the tower shell21or less are inserted in the tower coupling space50which is preliminarily provided in the foundation B and is not filled with concrete yet.

The tower coupling space50is a space provided in a center portion to insert and mount the lower end of the tower2in the foundation B made of reinforced concrete. That is, in the foundation B in this case, reinforcing rods are driven in the periphery of the tower coupling space50, and concrete filled between the reinforcing rods is solidified.

The tower coupling space50is provided with the foundation-side brackets (foundation-side coupling member)51integrated with the foundation B and held by the concrete. The foundation-side bracket51is, for example, a steel plate member having an substantially I shape in section and provided with the flanges51aand51bat the upper and lower ends.

After the extension part of the inner cylinder32,32A and the tower-side coupling members (the tower-side bracket35, the ring diaphragm34, and the base plate33) are inserted in the tower coupling space50, the foundation-side bracket51and the tower-side coupling members are coupled with the splice plates60and the bolts and nuts70. After that, the tower coupling space50in the space which is not filled with concrete is filled with concrete and the concrete is solidified, thereby completing providing of the tower2upright on the foundation B.

Therefore, there is no member like the base plate22larger than the outside diameter of the tower shell21. The outside diameter of the tower shell21can be increased to the constraint condition, and the section efficiency can be improved. That is, as the maximum outside diameter of the tower2, the outside diameter of the tower shell21can be used.

In the wind turbine generator of the foregoing embodiments, the outside diameter of the tower shell21can be used as the maximum diameter of the tower2. Therefore, the outside diameter of the tower shell21can be increased to the maximum and the section efficiency is improved. In addition, the tower supporting structure whose outside diameter is increased as much as possible within the range in which the weight can be reduced is realized. That is, in the wind turbine generator1having the monopole tower2, by employing the tower supporting structure of the foregoing embodiments, the outside dimension of the tower shell21can be maximized.

As a result, it becomes easier for the tower2which becomes more expensive and, moreover, in which the loading condition becomes stricter as the size of the wind turbine generator1increases to realize both satisfaction of the constraint condition such as transport limitation and assurance of necessary strength. Moreover, the wind turbine generator having the tower supporting structure realizing reduced thickness of the tower2and reduced weight is obtained.

Further, an inexpensive roll steel plate can be used for the brackets35and51, the splice plates60, and the like and, in addition, the expensive base plate22, the anchor bolts10, and nuts11become unnecessary, so that the cost of the wind turbine generator1can be reduced.

Further, the anchor bolts10are not used, so that maintenance such as refastening is also unnecessary.

When the outside diameter of the tower shell21increases, the flange diameter in a coupling which couples the tower sections also increases. Thus, the size and quantity of bolts that couple the flange can be reduced.

The present invention is not limited to the foregoing embodiments but can be properly changed without departing from the gist. The invention can be applied to, for example, both of the up-wind type and the down-wind type.