Rotary motor actuator and horizontal axis wind turbine

A rotary moto actuator with a base 22, a table 21, a stator 25 and a rotor 26 of a rotary motor 31 and a first member 12 and a second member 14 of a guide mechanism 24 that have a plurality of base segments 22a, a plurality of table segments 21a, a plurality of stator segments 25a, a plurality of rotor segments 26a, a plurality of first member segments 12a and a plurality of second member segments 14, respectively, which all arranged circumferentially around a center line C. The stator segments 25a are connected to the base segments 22a, to which the first member segments 12a are connected. The rotor segments 26a are connected to the table segments 21a, to which the second member segments 14a are connected.

TECHNICAL FIELD

The present invention relates to a rotary motor actuator that has a table rotating relative to a base around a predetermined center line, and to a horizontal axis wind turbine with the rotary motor actuator built therein.

BACKGROUND ART

A wind turbine is a device in which a rotor with aerofoils rotates by wind force thereby to convert wind energy to power of the rotor. The horizontal axis wind turbine is defined as a wind turbine in which the rotation axis of the rotor is located approximately in the horizontal plane. On the ground, a tower is installed to support the rotor at a predetermined height above the ground. At the upper part of the tower, a nacelle is arranged. In the nacelle, the rotation axis of the rotor, a power generator and a controller are accommodated. The power generator generates power upon receiving the rotational force of the rotor.

Between the tower and the nacelle, there is installed a yaw drive unit for turning the nacelle relative to the tower in the horizontal place in accordance with the wind direction in such a manner that the aerofoils are kept against the wind that varies in direction (for example, see PL1). A controller operates the yaw drive unit to control the deviation angle between the wind direction and the rotation axis of the rotor to be a predetermined angle or less. The yaw drive unit has a large ring-shaped gear provided in the tower and a geared motor with pinion provided in the nacelle. The pinion of the geared motor engages with the ring gear of the tower. When the geared motor is turned, the pinion rotates on its axis and rotates around the ring gear. With rotation of the pinion, the nacelle turns in the horizontal plane.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

As the gears engage with each other, there exist backlash between the pinion and the gear. When the wind turbine is hit by blown wind or wind in the lateral direction, the backlash causes the pinion and the gear into friction, of which gear surfaces wear, sometimes resulting in early breakage.

If a direct drive system motor, which is capable of transmitting the motor rotation directly to the nacelle, is used, the transmission can be eliminated and the above-mentioned problem due to the backlash of the gears can be solved. However, a motor for maintaining the number of revolutions constantly low has a physical problem of upsizing in order to obtain necessary torque as compared with the motor with a high number of revolutions. When the motor is upsized, it is difficult to manufacture, and as the weight increases with size, the assembly process of the motor at the upper part of the tower becomes dangerous.

Then, the present invention aims to provide a rotary motor actuator capable of simplifying the manufacturing and assembly process and also provide a horizontal axis wind turbine with the rotary motor actuator built therein.

Solution to Problem

Hereinafter, explanation is made about the present invention.

In order to solve the above-mentioned problems, a first aspect of the present invention is a rotary motor actuator which has a table rotating relative to abase around a center line, comprising: a rotary motor that has a stator and a rotor opposed to the stator and is configured to rotate the table relative to the base around the center line; and a guide mechanism which has a first member and a second member mounted movable on the first member via a plurality of rolling elements and which guides rotation of the table relative to the base around the center line, wherein the base, the table, the stator, the rotor, the first member and the second member have a plurality of base segments, a plurality of table segments, a plurality of stator segments, a plurality of rotor segments, a plurality of first member segments and a plurality of second member segments, respectively, which are arranged in a circumferential direction around the center line, one of the stator segments and the rotor segments is connected to the base segments, and one of the first member segments and the second member segments is connected to the base segments, and the other of the stator segments and the rotor segments is connected to the table segments, and the other of the first member segments and the second member segments is connected to the table segments.

Another aspect of the present invention is a horizontal axis wind turbine having a yaw drive unit for turning a nacelle, which support a rotor, relative to a tower around a yaw axis in such a manner that a rotation axis of the rotor rotated by a wind force extends against wind, wherein the yaw drive unit has: a rotary motor that has a stator and a rotor opposed to the stator and is configured to rotate a table fixed to the nacelle relative to a base fixed to the tower around the yaw axis, and a guide mechanism which has a first member and a second member mounted movable on the first member via a plurality of rolling elements and which guides rotation of the table relative to the base around the yaw axis, the base, the table, the stator, the rotor, the first member and the second member have a plurality of base segments, a plurality of table segments, a plurality of stator segments, a plurality of rotor segments, a plurality of first member segments and a plurality of second member segments, respectively, which are arranged in a circumferential direction around the yaw axis, one of the stator segments and the rotor segments is connected to the base segments, and one of the first member segments and the second member segments is connected to the base segments, and the other of the stator segments and the rotor segments is connected to the table segments, and the other of the first member segments and the second member segments is connected to the table segments.

Advantageous Effects of Invention

According to the rotary motor actuator of the one aspect of the present invention, the segments of the rotary motor and the segments of the guide mechanism are first combined into modules, which are then assembled into the rotary motor actuator as a whole. With this structure, it is possible to facilitate the manufacture process of the large-sized rotary motor actuator.

According to the horizontal axis wind turbine of the other aspect of the present invention, the segments of the rotary motor and the segments of the guide mechanism are first combined into modules on the ground, which are then arranged circumferentially around the yaw axis and assembled, in the air (at the upper part of the tower), into the yaw drive unit as a whole. With this structure, it is possible to simplify the assembly process of the yaw drive unit in the air and also facilitate transfer of the modularized yaw drive unit to the air.

DESCRIPTION OF EMBODIMENTS

With reference to the attached drawings, description will be made about a rotary motor actuator according to one embodiment of the present invention.FIG. 1is a perspective view of a horizontal axis wind turbine in which the rotary motor actuator according to the one embodiment of the present invention is installed. This horizontal axis wind turbine is a device for rotating a rotor4with blades by wind force, and converting wind power energy into power for the rotor4. The rotor4has a hub2that rotates around the horizontal rotation axis3, a plurality of blades1arranged on the hub2radially, and a rotation axis3that transmits rotation of the hub2to a transmission5. The hub2and plural blades1make up an aerofoil. The rotational force of the rotation axis3of the rotor4is transmitted via the transmission5to a power generator6. The power generator6generates power upon receiving the rotational force of the rotor4. The rotation axis3of the rotor4, the transmission5and power generator6are accommodated in a nacelle7.

On the ground, a tower8is installed to support the rotor4at the predetermined height. At the upper part of the tower8, a nacelle7is arranged rotatable around the vertical axis. Between the tower8and the nacelle7, a yaw drive unit10is arranged that turns the nacelle7in the horizontal plane. The yaw drive unit10turns the nacelle7in the horizontal plane in accordance with the wind direction in such a manner that the aerofoils of the rotor4are kept against the wind that varies in direction. A controller (not shown) stored in the nacelle7operates the yaw drive unit10to control a deviation angle between the wind direction and the rotation axis3of the rotor4to be a predetermined angle or less. The rotary motor actuator according to the one embodiment of the present invention is arranged between the tower8and the nacelle7to function as the yaw drive unit10.

The horizontal axis wind turbine has a base side unit which is fixed to the tower8and a table side unit which is fixed to the nacelle side.FIG. 2is a plane view of the base side unit of the rotary motor actuator andFIG. 3is a cross sectional view of the rotary motor actuator. Between the base22of the rotary motor actuator and the table21, the rotary motor31and the guide mechanism24are arranged. On the base22, a ring-shaped stator25of the rotary motor31is connected thereto. On the table21, a ring-shaped rotor26of the rotary motor31is connected thereto.

Connected to the base22is a ring-shaped raceway rail12as the first member inside the ring-shaped stator25. On the table21, plural moving blocks14are connected as second members. The moving block214are mounted on the raceway rail12movable in the circumferential direction (seeFIG. 7). The base side unit and the table side unit are equally split into, for example, five modules in this embodiment. In other words, the five modules are arranged circumferentially around the center line C of rotation of the rotary motor31.

FIG. 4is a plan view of the base side module,FIG. 5is a cross sectional view thereof andFIG. 6is a perspective view thereof. The base side module has a base segment22asplit into a sector, an arc-shaped stator segment25aconnected to the upper surface of the base segment22a, and an arc-shaped raceway rail segment12aconnected to the inside of the stator segment25aon the upper surface of the base segment22a. That is, in the base side module, the stator segment25aand the raceway rail segment12aare combined into one piece. The base segment22ais one obtained by splitting the ring-shaped stator25into five. The raceway rail segment12ais one obtained by splitting the ring-shaped raceway rail12into five. The base22, the stator25and the raceway rail12are equal in the number of split parts (five in this embodiment), and the stator segments25aand the raceway rail segments12aare the respective base segments22a.

The base segment22ais formed into a sector shape. When five base segments22aare combined, the ring-shaped base22is configured. In the outer rim of the base segment22a, through holes33are formed to connect the base segment22to the upper part of the tower8. The base segment22is connected to the tower8by passing a bolt into each through hole33and tightening the bolt to the upper part of the tower8.

On the upper surface of the base segment22a, the arc-shaped stator segment25ais connected thereto. The stator segment25ais a core16made of a magnetic material wound with plural coils15. The core16has an arc-shaped main body16aand a plurality of salient poles16bjutting from the main body16aradially to the inside (seeFIG. 4). Each of salient poles16bis wound with the coils15. The ring-shaped stator25is split equally and circumferentially and all the stator segments25aare equal in circumferential length.

Every three coils15form one coil group of three-phase (U, V and W phases) coils. When three-phase alternate current of which phase is 120-degree shifted from each other flows into the three-phase coils15, a moving magnetic field moving in the circumferential direction is generated on the salient poles16bof the core16. The plural salient poles16bof this core16faces rotor segment26amade of field permanent magnet, which is described later, in such a manner as to create a magnetic gap therebetween. The stator segment26ais given thrust by the moving magnetic field generated at the salient poles16bof the core16and turns around the center line C of the base22(seeFIG. 2). As illustrate d inFIG. 4, in the main body16aof the core16, through holes35are formed. The stator segment25ais connected to the base segment22aby passing a bolt into each through hole35and tightening the volt to the base segment22a.

As illustrated inFIG. 6, the arc-shaped raceway rail segment12ais connected to the inside of the stator segment25aon the upper surface of the base segment22a. In the inner peripheral surface of the raceway rail segment12a, two, upper and lower, rolling-element rolling grooves36are formed along the circumferential direction for rolling balls as rolling elements. The number of rolling-element rolling grooves36may be determined appropriately in accordance with load to bear. Each rolling-element rolling groove36has a cross sectional shape of combined two arcs, that is Gothic arch groove. Balls13(seeFIG. 3) interposed between the raceway rail segment12aand the moving block14are in two-point contact with the Gothic arch groove. In the raceway rail segment12a, through holes34are formed. The raceway rail segment12ais connected to the base segment22aby passing a bolt into each through hole34an tightening the bolt to the base segment22a.

As illustrated inFIG. 3, the table21is split into five table segments21a. The rotor26connected to the table21is also split into five rotor segments26a. The table21and the rotor26are equal in the number of splits parts and each rotor segment26ais connected to a corresponding table segment21a.

The planar shape of the rotor segment26aconnected to the bottom surface of the table segment21ais an arc. The rotor segment26ais arranged radially outside the raceway rail segment12aand radially inside the stator segment25a. Between the rotor segment26aand the stator segment25a, there is created a magnetic gap g. In order to prevent interference between the raceway rail segment12aand the rotor segment26a, a small gap is also created between the raceway rail12aand the rotor segment26a.

The rotor segment26ahas a yoke18that is made of a magnetic material and has a U-shaped cross section and permanent magnets17arranged in the groove of the yoke18. The yoke18extends in the circumferential direction and the plural permanent magnets17are arranged in the groove of the yoke18in the circumferential direction. Each permanent magnet17is magnetized radially. Plural permanent magnets are arranged in such a manner that N poles and S poles are formed alternately in the circumferential direction on the outer periphery of the rotor segment26a. The rotor26is split circumferentially and equally and all the rotor segments26are equal in circumferential length.

On the lower surface of the table segment21a, the moving block14is connected thereto.FIG. 7illustrates plural moving blocks14arranged on the ring-formed raceway rail12. On the inner peripheral surface of the raceway rail in the assembly state, plural, for example, five moving blocks14are arranged equally separated from each other in the circumferential direction. The moving blocks14cooperate with the raceway rail12to guide the table21rotating relative to the base22around the center line C. As the plural moving blocks14are arranged on the raceway rail12equally separated from each other, it is possible to equally bear loads in 360-degree all directions on the table21.

As described above, the table side module has a table segment21a, a rotor segment26aconnected to the lower surface of the table segment21aand the moving block14connected to the lower surface of the table segment21a. That is, in the table side module, the rotor segment26aand the moving block14are combined into one piece.

Here, in this embodiment, five moving blocks14are connected to five table segments21a. However, there is no need to connect all the table segments21ato the moving blocks14, and some table segments21amay be not connected to the moving blocks14or one table segment21amay be connected two or more moving blocks14. The number of moving blocks14may be two or more. If the number of table segments21adiffers from the number of moving blocks14, it is possible to avoid the possibility that all the moving blocks14are arranged at joints of the raceway segments12aand thereby to smooth rotation of the table21.

In the upper surface of the moving block14, a plurality of tap holes27is formed. As illustrated inFIG. 3, a bolt is passed through a through hole38of the table segment21aand the bolt is fit in the tap hole37of the moving block14thereby to connect the moving block14to the table segment21a.

FIG. 8is a horizontal cross sectional view of the moving block14. The moving block14is arranged in such a manner as to face the inner peripheral surface of the raceway rail segment12aand it is mounted on the raceway rail segment12avia plural balls13rolling on the rolling-element rolling groove12bof the raceway rail segment12a. Each moving block14has a block main body40and end plates41afixed to both ends of the block main body40. In the block main body40, two, upper and lower, loaded rolling-element rolling grooves40aare formed opposed to the two, upper and lower, rolling-element rolling grooves12bof the raceway rail segment12a. Each loaded rolling-element rolling groove40ahas across sectional shape composed of two arcs and it is a so-called Gothic arch groove. A loaded rolling-element rolling path is formed between the rolling-element rolling groove12bof the raceway rail segment12aand the loaded rolling-element rolling groove40aof the moving block14. The balls13roll, under load, on this loaded rolling-element rolling path.

In the moving block main body40, a rolling-element return path40bis formed approximately in parallel to the loaded rolling-element rolling groove40a. In each end plate41, a U-shaped direction change path41ais formed that connects the loaded rolling-element rolling groove40aof the moving block main body40to the rolling-element return path40b. The rolling-element return path40band the paired U-shaped direction change paths41aform an unloaded return path that connects one end of the loaded rolling-element rolling groove40ato the other end. Once the paired endplates41are secured to the moving block main body40, a circuitry rolling-element circulation path is completed. Here, in the assembled state, supporting means such as pressure rings may be arranged inside the moving block14in order to prevent the moving block14from being separated from the raceway rail12.

As described above, after the base side modules are assembled one by one (in other words, the raceway rail segments12aand the stator segments25aare connected to the respective base segments22a), the plural base segments22aare arranged in the circumferential direction around the center line C and combined. Then, the arc-shaped stator segments25aare connected together into a ring-shaped stator25. Besides, the arc-shaped raceway rail segments12aare connected together into a ring-shaped raceway rail12.

In the same way, after the table side modules are assembled one by one (in other words, the rotor segments26aand the moving blocks14are connected to the respective table segments21a), the plural table segments21aare arranged in the circumferential direction around the center line C and combined. Then, the arc-shaped rotor segments26aare connected together into a ring-shaped rotor26. When the moving blocks14are mounted on the raceway rail12, the rotary motor actuator is completed. When three-phase alternate current flows into coils15as the stator in this state, a rotational force is given to the table21so that the table21rotates relative to the base22.

When the above-described rotary motor actuator is mounted on the horizontal axis wind turbine, first, the plural base side modules are assembled one by one on the ground and prepared as tower side modules. And, the plural table side modules are assembled one by one and prepared as nacelle side modules.

Next, at the upper part of the tower installed on the ground, the plural tower side modules are arranged in the circumferential direction around the yaw axis and combined integrally. With this process, the arc-shaped stator segments25aare connected together into the ring-shaped stator25. Besides, the arc-shaped raceway rail segments12aare connected together into the ring-shaped raceway rail12.

Then, at the upper part of the tower installed on the ground, the plural nacelle side modules are arranged in the circumferential direction around the yaw axis and combined together. With this process, the arc-shaped rotor segments26aare connected together into the ring-shaped rotor26. Then, the moving blocks14are mounted on the raceway rail12, the guide mechanism is completed.

As described above, according to this embodiment, the rotary motor actuator can be manufactured by first combining and assembling the segments of the rotary motor and segments of the guide mechanism into modules and then, arranging the plural modules in the circumferential direction around the center line. This process makes it easy to manufacture a large-sized rotary motor actuator.

As the curve guide having a curve raceway rail12and a plurality of moving blocks14mounted on the raceway rail12is used as the guide mechanism, it becomes easy to configure the guide mechanism comprised of circumferentially split parts.

As the base22, the stator25and the raceway rail12are equal in the number of split parts and the stator segments25aand raceway segments12aare connected to the respective base segments22a, manufacture of each module at the base side can be facilitated. Besides, as the table21and the stator26are equal in the number of split parts and the table segments21aare connected to the respective rotor segments26a, manufacture of each module at the table side can be facilitated.

As the rotary motor31is arranged radially outside the raceway rail12, it is possible to increase the rotational force of the rotary motor31.

As the raceway rail12is composed of plural arc-shaped raceway rail segments12asplit therefrom, it is possible to improve the material availability and eliminate the need to use a large-sized processing machine, as compared with the case of manufacturing an un-split ring-shaped raceway rail12. This consequently facilitates the manufacturing process of the raceway rail itself.

When the rotary motor actuator of this embodiment is mounted in the horizontal axis wind turbine, the rotary motor segments and the guide mechanism segments are combined into respective modules on the ground and then, the modules are arranged in the circumferential direction around the yaw axis thereby to configure the yaw drive unit of the horizontal axis wind turbine. With this configuration, it is possible to simplify the assembly process of the yaw drive unit up in the air and also the transfer process of the modularized yaw drive unit to the air.

Here, the present invention is not limited to the above-mentioned embodiments and may be embodied in various forms without departing from the scope of the present invention. In the above-described embodiments, the base is a fixed side and the table is a movable side. However, these may be changed so that the table may be the fixed side and the base may be the rotation side. Further, the base and the table may be used flipped vertically.

Further, when it is used in a part which oscillates without making one turn, it can use combined modules corresponding to required angles and there is no need to combine all the modules into a ring.

Further, the guide mechanism used may be a slewing bearing that has an outer ring as a first member and an inner ring mounted on this outer ring via rolling elements, other than the curve guide. The first member segment may be an arc part as a part of the outer ring and the second member segment may be an arc part as a part of the inner ring.

Furthermore, the rotary motor may be arranged inside of the raceway rail. In this case, the rotary motor actuator may be more compact.

The present specification is based on Japanese Patent Applications No. 2009-253251 filed on Nov. 4, 2009, the entire contents of which are expressly incorporated by reference herein.

INDUSTRIAL APPLICABILITY

The rotary motor actuator of the present invention is applicable to the yaw drive unit for turning a rotation axis of a rotor of a horizontal axis wind turbine in the horizontal plane as well as a pitch drive unit for turning the rotation axis of the rotor in the vertical plane. Besides the wind turbine, it is applicable to a turning machine in which a driver seat or an upper frame is mounted turnable relative to a track frame as a lower structural element. It is also applicable to a turn table for turning a work such as a glass board for large-sized screen display.

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