US20040247437A1

US20040247437A1 - Wind power generator

Info

Publication number: US20040247437A1
Application number: US10/487,257
Authority: US
Inventors: Ryoichi Otaki; Hiroyuki Itoh; Oshima Atsushi; Hideo Okano
Original assignee: NSK Ltd
Current assignee: NSK Ltd
Priority date: 2001-10-25
Filing date: 2001-12-12
Publication date: 2004-12-09
Also published as: WO2003036083A1

Abstract

A transmission 3 is provided between a propeller that catches wind to rotate and a generator 5 which is a friction roller transmission of the wedge type functioning as a speed increaser whereby a structure with good generating efficiency is realized with low noise for use in a normal home etc.

Description

FIELD OF THE INVENTION

This invention relates to improvements to a wind-powered electric generating apparatus that uses wind power to generate electric power, and more particular to a wind-powered generating apparatus that can efficiently generate electric power even at low wind speeds, and that can be easily installed in a normal home or small business site etc.

BACKGROUND OF THE INVENTION

In recent years, much attention has been placed on wind-powered electricity generation as a method of using natural energy to generate electric power with the objective to improve the global environment by reducing carbon dioxide. A wind-powered generating apparatus uses kinetic energy from the wind to turn a propeller, and the generator is operated and driven by the rotating shaft that is connected to the center of the propeller. Conventionally, in a typically used wind-powered generating apparatus the propeller and generator were connected directly without going through a transmission, or were connected by way of a gear-type transmission (speed-increaser).

On the other hand, Japanese patent publication Tokukai Hei 2-157483 discloses a wind-powered generator in which a continuously variable transmission of the toroidal-type, that is traction transmission, is placed between the propeller and the generator such that the generator is operated and driven at a constant speed regardless to changes in rpm of the propeller.

In the case of construction in which the propeller is directly connected to a typical generator, often it is not possible to obtain sufficient generating efficiency because the rotation speed of the generator rotor is slow.

Moreover, in the case of construction in which the propeller and generator are connected by way of a gear-type transmission (speed-increaser), large noise is generated by this transmission section during operation, so there is the possibility of noise problems occurring when installed near locations where people live such as near private homes.

Furthermore, in the case of construction in which a continuously variable transmission of the toroidal type is used, not only does the cost become high, but it is difficult to increases the speed-increasing ratio, and it is difficult to obtain a generating apparatus that is compact and that has good generating efficiency.

Therefore, in the conventional construction, it was difficult to obtain a wind-powered generating apparatus that could be easily installed in a normal home or small business site etc. and that had good generating efficiency.

The wind-powered generating apparatus of this invention was invented taking the problems mentioned above into consideration.

DISCLOSURE OF THE INVENTION

As in the conventionally known wind-powered generating apparatus, the wind-powered generating apparatus of this invention comprises a propeller that receives wind and is turned by the wind, a transmission in which the propeller is connected to the end of the input shaft, and a generator that is operated and driven by the output shaft of the transmission, and where the transmission is a wedge-action type traction-roller transmission.

Also, this wedge-action type traction-roller transmission comprises an outer ring, center roller, a plurality of support shafts and a plurality of intermediate rollers.

Of these, the outer ring rotates together with the rotation of the input shaft, so its inner peripheral surface is taken to be the drive-side cylindrical surface.

The center roller rotates together with the output shaft, so its outer peripheral surface is taken to be the driven-side cylindrical surface.

Also, each of the support shafts is located in the annular space between the driven-side cylindrical surface and drive-side cylindrical surface, and they are parallel with the center roller.

Moreover, the intermediate rollers are supported by the support shafts such that they can rotate freely, and the outer peripheral surfaces of these intermediate rollers are taken to be drive-force-transmission cylindrical surfaces.

Furthermore, by making the center of the center roller eccentric with the center of the input shaft and outer ring, the width in the radial direction of the annular space is made non-uniform around the circumferential direction, and some of the plurality of intermediate rollers are movable rollers that are supported such that they can freely move in at least the circumferential direction of the annular space, and the remaining intermediate rollers are guide rollers.

Also, when the center roller and outer ring are rotated in a specified direction at a speed ratio that is best suitable for the transmission ratio between the output shaft and input shaft, the intermediate rollers that are movable rollers, freely move toward the section with the narrow width of the annular space.

Moreover, the wind-powered generating apparatus comprises a propeller that catches the wind to rotate, and a generator that is driven by the propeller to rotate; and where the generator is an axial-type slotless generator that comprises: a generator case; a rotating shaft that is supported inside the generator case such that it can freely rotate together with the output shaft of the transmission; a plurality of yokes made of a magnetic material and that are fastened at intervals in the axial direction around the outer peripheral surface of the rotating shaft; permanent magnets that are supported by the sides in the axial direction of the yokes and which are arranged such that the S-poles and N-poles alternate in the circumferential direction; a plurality of coil holders that are fastened to the inner peripheral surface of the generator case in the section where the phase in the axial direction is away from the yokes; and a plurality of coils that is held on each of the sides in the axial direction of each coil holder such that they face the permanent magnets.

The wind-powered generating apparatus of this invention, constructed as described above, can be easily installed in a normal home or small business site etc., and has a good generating efficiency.

In other words, in the case of a wind-powered generating apparatus having the transmission, the rotation of the propeller that is turned by catching the wind is increased by the transmission and transmitted to the generator, so electric power can be generated with good efficiency even at low wind speeds. Particularly, in the case of a wedge-action type traction-roller transmission, the surface pressure between the drive-transmission cylindrical surfaces, which are the outer peripheral surfaces of each of the intermediate rollers, and the driven-side cylindrical surface, which is the outer peripheral surface of the center roller and the drive-side cylindrical surface, which is the inner peripheral surface of the outer ring, is low in the stopped state, and thus the torque required to start turning the input shaft (starting torque) is small. Therefore, it is possible for the propeller to start rotating even when there is little wind, and the generating efficiency is improved by that amount.

Moreover, since the transmission is a traction-roller-type transmission, the amount of noise generated during operation is less than when using a gear-type transmission, thus it is more difficult for a noise problem to occur even near where people live such as near private homes.

Furthermore, the traction-roller transmission is a wedge-action type transmission, and the surface pressure at the point of contact between each of the drive-transmission cylindrical surfaces and the driven-side cylindrical surface and drive side cylindrical surface adequately changes according to the size of the rotation force (torque) that is transmitted from the input shaft to output shaft. Therefore, the rotation force of the propeller can be very efficiently transmitted to the generator regardless of fluctuation in the changing rotation force of the propeller due to the wind speed. The surface pressure at the aforementioned point of contact rises after the propeller starts rotating, so this rise in surface pressure does not hinder the propeller when it starts rotating.

Also, in the case of a wind-powered generating apparatus that does not require that the transmission be installed, the generator only needs a small driving torque, and by using a very efficient axial-type slotless generator, electric power can be generated with good efficiency. Therefore, naturally in the case of using a wedge-action type traction-roller transmission between the propeller and generator, as well as in the case in which the propeller is connected directly to the generator without using a transmission, it is possible to obtain the required amount of electric power generation. Furthermore, since the driving speed of the generator is kept low, it is possible to keep noise generated by the transmission low even when using a gear-type transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of an first example of the embodiment of the present invention. [0023]
FIG. 2 is an enlarged view of a center-upper portion of FIG. 1. [0024]
FIG. 3 is a cross sectional view taken along the line A-A in FIG. 2. [0025]
FIG. 4 is an enlarged cross sectional view taken along the line B-B in FIG. 3. [0026]
FIG. 5 is a cross sectional view of a second example of the embodiment of the present invention. [0027]
FIG. 6 is a cross sectional view of the third example of the embodiment of the present invention. [0028]
FIG. 7 is an enlarged view of Portion C in FIG. 6. [0029]
FIG. 8 is a view from the left side of FIG. 7 where the yokes and permanent magnet are taken out from the generator. [0030]
FIG. 9 is a view from the left side of FIG. 7 where the coil holder and coil are taken out from the generator. [0031]
FIG. 10 shows a basic structure of the general slotless generator, where (A) a cross sectional view with respect to the phantom plane including the central axis, and (B) a cross sectional view with respect to the phantom plane orthogonal to the central axis. [0032]
FIG. 11 is a view similar to FIG. 10(A), to show a condition where the diameter of the slotless generator is made large to increase its generating capacity. [0033]
FIG. 12 is a view similar to FIG. 10(A), to show a condition where the axial length of the slotless generator is made large to increase its generating capacity. [0034]
FIG. 13 is a view similar to FIG. 10(A), to show an arrangement where a plurality of slotless generators are arranged in the axial direction to increase its generating capacity.[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. [0036] 1 to 4 show a first example of the embodiment of this invention. Similar to the conventionally well-known wind-powered generating apparatus, the wind-powered generating apparatus of this invention comprises: a propeller 1 that catches the wind to rotate; a transmission 3 in which the end of its input shaft 2 is connected to the propeller 1; and a generator 5 that is driven for rotation by the output shaft 4 of the transmission 3. In other words, the rotation of the propeller 1 is transmitted to the rotor 6 of the generator 5 by way of the transmission 3, and that causes the rotor 6 to rotate inside the stator 8 that is located around the inner peripheral surface of the generator casing 7 such that an electromotive force is induced in the stator 8.
The [0037] main unit 9 of the generating apparatus, which includes the propeller 1, transmission 3 and generator 5, is supported at the top of a fixed support pole 10 such that it can freely rotate around the vertical axis. In other words, a hollow, cylindrical-shaped rotating shaft 11, which protrudes from the bottom surface of the main unit 9, is rotatably supported at the top of a hollow, cylindrical-shaped support pole 10, which is fixed in the vertical direction from the ground or roof top etc., by a rolling bearing 12, such as a deep-groove ball bearing that supports radial loads and axial loads. The center of gravity of the main unit 9 is located on the extension line from the center axis of the rotating shaft 11, so the inclination moment that is applied to the rotating shaft 11 is only from the force of the wind. Therefore, the main unit 9 rotates freely around this rotating shaft 11 by just a light force. Taking the average wind speed received by the propeller 1 into consideration, the extension line from the center axis of the rotating shaft 11 can be located a little closer toward the propeller 1 than the center of gravity of the main unit 9.
In any case, the [0038] cable 13 for obtaining the electric power generated by the generator 5 is located inside the internal space of the rotating shaft 11 and support pole 10. A slip ring (not shown in the figure) is located in the middle of this cable 13 so that the cable 13 does not become twisted regardless of the rotation of the main unit 9. Also, in the case of wind-powered electric generation, the amount of electric power generated frequently changes due to changes in the wind speed, so a battery, for example, can be connected to the end of the cable 13, and the power stored in this battery can be used at any time.
On the other hand, by storing all of the components of the [0039] transmission 3 inside a housing 14, the transmission 3 can be integrated into a single unit. This housing 14 comprises a cylindrical-shaped main housing unit 15 with bottoms made of steel or an aluminum-alloy, and a cover 16 for covering the opening on the base end of the main-housing unit 15 that is also made of steel or an aluminum alloy. The inner half (left half in FIGS. 1 and 2) of the center roller 17 is inserted through the inside of the housing 14 by way of a through hole 18 that is formed in the center of the cover 16. This through hole 18 is located just a little off from the center of the cover 16. Also, the end of the rotating shaft 19 of the generator 5, which is also the output shaft 4, is connected to the outside end (right end in FIGS. 1 and 2) of the center roller 17. In the example shown in the figures, the center roller 17, which has a smaller diameter than this rotating shaft 19, is integrally formed on the end of the rotating shaft 19. Also, both ends of this rotating shaft 19 are rotatably supported in the bottom of the generator casing 7 and cover 16 by a pair of rolling bearings 20, such as deep-groove or angular ball bearings that are capable of supporting both radial and axial loads. Moreover, there is a seal ring 21 located between the inner peripheral surface of the through hole 18 and outer peripheral surface on the end of the rotating shaft 19, so that lubrication such as traction grease inside the housing 14 does not get into the side of the generator casing 7.
Also, there are three [0040] support shafts 22, 22 a inside the housing 14 in the section around the center roller 17, and they are arranged such that they are parallel with the center roller 17. In other words, one end (right ends in FIGS. 1 and 2) of these support shafts 22, 22 a is supported by the cover 16, and the other end (left ends in FIGS. 1 and 2) is supported by a circular connecting plate 23 that is made of metal such as steel.
Of the three [0041] support shafts 22, 22 a, the two support shafts 22 are located at the top center and bottom left side in FIG. 3, and both ends of these support shafts 22 fit into and are fastened to fitting holes 24 that are formed in the cover 16 and connecting plate 23. Therefore, neither of these support shafts 22 move in the circumferential direction or radial direction inside the housing 14. On the other hand, the remaining support shaft 22 a is located on the bottom right side in FIG. 3, and the ends of this support shaft 22 a are supported with reference to the cover 16 and connecting plate 23 and can move a little in the circumferential direction and radial direction of the housing 14. In order to do this, there are support holes 25 formed in the cover 16 and connecting plate 23 in the sections in alignment with both ends of the support shaft 22 a, and they have a width and length that are larger than the outer diameter of the support shaft 22 a such that both ends of the support shaft 22 a fit loosely in these support holes 25.
Also, located around the middle of these [0042] support shafts 22, 22 a, there are the guide rollers 26 a, 26 b and movable roller 27, which are the intermediate rollers, and they are rotatably supported by bearings 28, such as radial needle roller bearings. The connecting plate 23 comes in contact with protruding sections 29 that protrude from part of the inside surface of the cover 16 (surface on the side of the space where the guide rollers 26 a, 26 b and movable roller 27 are located, or left side in FIGS. 1 and 2) and that are located away from the guide rollers 26 a, 26 b and movable roller 27, and is connected and fastened to the cover 16 by connecting bolts 30. Also, there are thrust washers 31 a, 31 b rotatably provided between the surfaces on both ends in the axial direction of the guide rollers 26 a, 26 b and movable roller 27 and the connecting plate 23 and cover 16, respectively, in order that rollers 26 a, 26 b and 27 can rotate smoothly. In order to make the best use of the function of the thrust washers 31 a, 31 b as sliding bearings, it is preferable that the thrust washers 31 a, 31 b be made of a material with a low coefficient of friction such as polyamide resin, polyacetal resin or polyphenylene sulfide resin.
Moreover, there is a cylindrical-shaped [0043] outer ring 32 located on the inside of the housing 14 in the section that surrounds the guide rollers 26 a, 26 b and movable roller 27; and the inner peripheral surface of this outer ring 32 is the drive-side cylindrical surface 33. Also, this drive-side cylindrical surface 33 comes in contact with the driving-force-transmission cylindrical surfaces 34, 34, which are the outer peripheral surfaces around the guide rollers 26 a, 26 b and movable roller 27. Also, the base end (right end in FIGS. 1 and 2) of the input shaft 2 is connected to the outer ring 32 by way of a connecting plate 35. Moreover, a boss section 37, which is located in the section where the base end of the input shaft 2 connects to the center section of the outer ring 32, is supported in a cylindrical-support section 38 that is formed in the center section of the main-housing unit 15, and the section toward the tip end in the middle section of the input shaft 2 is supported in the apparatus housing 39, and they are supported such that they can rotate freely by a pair of rolling bearings 40 that can support both radial and axial loads, such as deep-groove or angular ball bearings. The center section of the propeller 1 is connected and fastened to the tip end (left end in FIGS. 1 and 2) of the input shaft 2 in the section that protrudes outward from the apparatus housing 39. There is a seal ring 41 located between the outer peripheral surface of the boss section 37 and the inner peripheral surface of the support cylindrical surface 38, so that foreign matter such as rainwater does not get inside the housing 14.
Moreover, in this embodiment, the [0044] outer ring 32 is located inside the housing 14 such that it can move freely a little in the rotational and radial directions. In other words, in this embodiment, the plurality of protrusions 42 that are formed around the outer peripheral surface of the connecting plate 35 fit with the notches 43 that are formed on the edge of one end (left end in FIGS. 1 and 2) in the axial direction of the outer ring 32 such that a little displacement in the radial direction is possible. Also, in the state where the protrusions 42 are forced into the bottom section of the notches 43 (right section in FIGS. 1 and 2), the retaining ring 45 is stopped in the groove 44 that is formed around the inner peripheral surface on the end of outer ring 32 such that the protrusions 42 do not come out of the notches 43. Also, the outer ring 32 and connecting plate 35 are connected to each other such that the torque can be freely transmitted, and such that they can move a little with respect to each other in the radial direction.
The driving-force-transmission cylindrical surfaces [0045] 34, which are the outer peripheral surfaces of the guide rollers 26 a, 26 b and moveable roller 27, come in contact with the driven-side cylindrical surface 46 that is formed around the outer peripheral surface of the center roller 17, and the drive-side cylindrical surface 33 that is formed around the inner peripheral surface of the outer ring 32. The center of the center roller 17 is eccentric with respect to the centers of both the input shaft 2 and the outer ring 32. In other words, as was described above, the through hole 18 though which the center roller 17 passes is located a little away from the center of the housing 14, however the cylindrical-support section 38 through which the input shaft 2 passes is located in the center of the housing 14. The outer ring 32 is substantially concentric with the input shaft 2 rotatably supported inside the cylindrical-support section 38. Accordingly, the outer ring 32 and input shaft 2 are eccentric with respect to the center roller 17 by the amount δ that the through hole 18 is displaced from the center of the housing 14. Also, the width dimension in the radial direction of the annular space 47, which is formed between the driven-side cylindrical surface 46 around the outer peripheral surface of the center roller 17, and the drive-side cylindrical surface 33 around the inner peripheral surface of the outer ring 32 in which the guide rollers 26 a, 26 b and movable roller 27 are located, is non-uniform in the circumferential direction by an amount that corresponds to the amount δ of eccentricity mentioned above.
The outer diameters of the [0046] guide rollers 26 a, 26 b and movable roller 27 differ by the amount that the width in the radial direction of the annular space 47 is non-uniform in the circumferential direction. In other words, the diameters of the guide roller 26 b and movable roller 27, which are located on the side (lower side in FIG. 3) that the center roller 17 is eccentric with respect to the outer ring 32, are the same to each other and are relatively small diameters. On the other hand, the diameter of the guide roller 26 a that is located on opposite side of the side that the outer ring 32 is eccentric with respect to the center roller 17 (upper side in FIG. 3) is larger than the diameters of the guide roller 26 b and movable roller 27. Also, the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of these three intermediate rollers or guide rollers 26 a, 26 b and movable roller 27, come in contact with the drive-side cylindrical surface 33 and driven-side cylindrical surface 46. In order to prevent excessive surface pressure due to edge loading from being applied in the areas where these surfaces 34, 33, 46 come in contact with each other, it is preferred that crowning be suitably performed for the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the guide rollers 26 a, 26 b and movable roller 27. In this case, the shape of the generatrix line of the cylindrical surfaces on the drive-side cylindrical surface 33 and driven-side cylindrical surface 46 can be kept to be a straight line.
Of the two [0047] guide rollers 26 a, 26 b and one movable roller 27, which are intermediate rollers, the support shafts 22 that support both of the guide rollers 26 a, 26 b are fastened on the inside of the housing 14 as described above. On the other hand, the support shaft 22 a that supports the movable roller 27 is supported inside the housing 14 as described above such that it can freely move a little in the circumferential direction and radial direction. Therefore, the movable roller 27 can also freely move a little inside the housing 14 in the circumferential direction and radial direction. Moreover, elastic members such as compression coil springs 49, which are mounted inside cylindrical holes 48 in the cover 16 and connecting plate 23, elastically press the support shaft 22 a that supports the movable roller 27, so as to move the movable roller 27, which is rotatably supported by the support shaft 22 a, in the direction toward the narrow-width section of the annular space 47. In the example shown in the figure, compression-coil springs 49 press a pair of pressure pins 51 the tip ends (bottom left ends in FIG. 3 and the bottom ends in FIG. 4) of which are formed into an outward facing flange-shaped collar sections 50, and both of these pressure pins 51 press both ends of the support shaft 22 a in the same direction.
Next, the function of the wind-powered generating apparatus of this invention, installed with the [0048] transmission 3 that is constructed as described above, will be explained.
The [0049] propeller 1 rotates when the wind blows. The apparatus housing 39 in which the main unit 9 is installed is supported such that it rotates freely with a vertical rotating shaft 11 as the center of rotation, and since there is a deflecting plate 52 located on the end of the apparatus housing 39 opposite from the propeller 1, the housing 39 rotates into the direction of the wind such that the propeller 1 can effectively catch the wind.
The rotation of the [0050] propeller 1 is transmitted to the outer ring 32 by way of the input shaft 2 and connecting plate 35 such that the outer ring 32 rotates in the clockwise direction of FIG. 3. Also, the rotation of this outer ring 32 is transmitted to the guide rollers 26 a, 26 b and movable roller 27 by way of the points of contact 53 a, 53 b on the outer-diameter side, which are the points of contact between the drive-side cylindrical surface 33 which is the inner peripheral surface of the outer ring 32, and the driving-force-transmission cylindrical surfaces 34, 34 which are the outer peripheral surfaces of the guide roller 26 a, 26 b and movable roller 27. Furthermore, the rotation of these guide rollers 26 a, 26 b and movable roller 27 is transmitted to the center roller 17 by way of the points of contact 54 a, 54 b on the inner diameter side, which are the points of contact between each of the driving-force-transmission cylindrical surfaces 34 and the driven-side cylindrical surface 46, which is the outer peripheral surface of the center roller 17. This rotation then drives for rotation the rotating shaft 19 of the generator 5, which is also the output shaft 4 that is integrally connected to the center roller 17, and the rotor 6 that is formed around the rotating shaft 19. As a result, an electromotive force is induced in the stator 8 that is located around the rotor 6, and this electric power is obtained by way of the cable 13.
When the [0051] outer ring 32 rotates in the clockwise direction of FIG. 3, the force applied from the outer ring 32 and the elastic force from each of the compression coil springs 49 moves the movable roller 27 inside the annular space that exists between the drive-side cylindrical surface 33 and the driven-side cylindrical surface 46 toward the narrow-width section of the annular space 47 (lower middle section in FIG. 3). As a result, the driving-force-transmission cylindrical surface 34, which is the outer peripheral surface of the movable roller 27 presses strongly against the driven-side cylindrical surface 46 and drive-side cylindrical surface 33. The contact pressure at the point of contact 54 b on the inner radially side of the movable roller 27, which is the point of contact between the driving-force-transmission cylindrical surface 34 and the driven-side cylindrical surface 46, and the contact pressure at the point of contact 53 b on the radially outer side of the movable roller 27, which is the point of contact between the driving-force-transmission cylindrical surface 34 and the drive-side cylindrical surface 33 becomes higher.
When the contact pressure at the radially inner and outer points of [0052] contact 54 b, 53 b on the movable roller 27 becomes higher, either the center roller 17 or outer ring 32 or both moves a little in the respective radial direction due to assembly gaps or elastic deformation etc. As a result, the contact pressure at the two inner points of contact 54 a, which are the points of contact between the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the remaining two intermediate rollers, or in other words, guide rollers 26 a, 26 b, and the driven-side cylindrical surface 46, which is the outer peripheral surface of the center roller 17, and the contact pressure at the two outer points of contact 53 a, which are the points of contact between the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the guide rollers 26 a, 26 b, and the drive-side cylindrical surface 33, which is the inner peripheral surface of the outer ring 32, become higher. Also, the center roller 17 rotates in the counterclockwise direction of FIG. 3.
The force that moves the [0053] movable roller 27 inside the annular space toward the narrow-width section of the annular space 47 changes due to the size of the torque transmitted from the outer ring 32 to the center roller 17. In other words, the larger the torque that is transmitted from the propeller 1 to the outer ring 32 by way of the input shaft 2 becomes, the larger the force that moves the movable roller 27 toward the narrow-width section of the annular space 47 becomes. Also, the larger this force becomes, the larger the contact pressure at the radially inner and outer points of contact 54 a, 54 b, 53 a, 53 b becomes. That is, when the drive torque is small, the contact pressure at the radially inner and outer points of contact 54 a, 54 b, 53 a, 53 b becomes small. Therefore, it is possible to make the contact pressure at the inner and outer points of contact 54 a, 54 b, 53 a, 53 b a suitable value that corresponds to the size of the torque that is transmitted between the input shaft 2 and the output shaft 4, and thus it is possible to raise the transmission efficiency of the traction-roller transmission.
On the other hand, in the case when the rpm of the [0054] center roller 17 becomes faster than the rpm corresponding to the rpm of the input shaft 2, including the case when the outer ring 32 rotates in the counterclockwise direction of FIG. 3 with the center roller 17 stopped, such as in the case when the direction of the wind changes suddenly and the propeller 1 catches the wind and rotates in the opposite direction before the direction of the main unit 9 changes, the movable roller 27 resists the elastic force of each of the compression coil springs 49 by the force applied from the center roller 17 or outer ring 32, and moves inside the annular space 47 toward the large-width section (right center section in FIG. 3) of the annular space 47. As a result, the driving-force-transmission cylindrical surface 34, that is the outer peripheral surface of the movable roller 27, stops pressing against the driven-side cylindrical surface 46 and the drive-side cylindrical surface 33. Also, the contact pressure at the radially outer contact points 53 a, 53 b, which are the points of contact between driving-force-transmission cylindrical surfaces 34 on the movable roller 27 and guide rollers 26 a, 26 b and driven-side cylindrical surface 46, and the contact pressure at the radially inner contact points 54 a, 54 b, which are the points of contact between the driving-force-transmission cylindrical surfaces 34 on the movable roller 27 and guide rollers 26 a, 26 b and the drive-side cylindrical surface 33, drops or disappears. As a result, rotation of the outer ring 32 is no longer transmitted to the rotation shaft 19. Therefore, even in the case of a direct-current type generator 5, there is no electromotive force induced in the opposite direction in the generator 5.
Furthermore, in the case of the traction-roller-[0055] type transmission 3 shown in the figures, it is possible to regulate the contact-surface pressure at the points of contact between the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the guide rollers 26 a, 26 b, and the driven-side cylindrical surface 46, which is the outer peripheral surface of the center roller 17, and the drive-side cylindrical surface 33, which is the inner peripheral surface of the outer ring 32, even when the outer diameters or installation positions of the guide rollers 26 a, 26 b displace a little, or when the components elastically deform, or when the outer ring 32 thermally expands. In other words, in the case when the outer diameters or installation positions of the guide rollers 26 a, 26 b displace a little, as the movable roller 27 moves into the narrow-width section of the annular space 47, the outer ring 32 displaces in the radial direction. Also, the contact-surface pressures at the points of contact between the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the guide rollers 26 a, 26 b and movable roller 27, and the driven-side cylindrical surface 46, which is the outer peripheral surface of the center roller 17, and the drive-side cylindrical surface 33, which is the inner peripheral surface of the outer ring 32 are made to be the design values. Therefore, it is possible to obtain a high transmission efficiency even when the outer diameters or installation positions displace a little, or when the components elastically deform. Moreover, even in the case when the center axis of the input shaft 2 is displaced a little from the center axis of the outer ring 32 due to assembly error or strong wind, the engagement section between the protrusions 42 and the notches 43, absorbs this displacement to prevent excessive stress from being applied to the components of the transmission 3.
The wind-powered generating apparatus of this invention, assembled with a wedge-action type traction-roller transmission for the [0056] transmission 3 as described above can easily be installed in a typical home or small business site, and can improve generation efficiency.
In other words, the rotation of the [0057] propeller 1 that catches the wind and rotates is increased in speed by the transmission 3 and transmitted to the generator 5, so even in the case of low wind speed, the rotor 6 of the generator 5 rotates at high speed and generation is performed with good efficiency. Particularly, when the wedge-action type traction-roller transmission is in the stopped state, the surface pressure is low at the points of contact between the driving-force-transmission cylindrical surfaces 34, which are the outer peripheral surfaces of the movable roller 27 and guide rollers 26 a, 26 b, and the driven-side cylindrical surface 46, which is the outer peripheral surface of the center roller 17, and the drive-side cylindrical surface 33, which is the inner peripheral surface of the outer ring 32. Therefore, the torque required to start the rotation of the input shaft 2 that is connected to the outer ring 32 (starting torque) is small. Therefore, it is possible to start rotation of the propeller 1 even when there is very little wind, and thus it is possible to improve the generating efficiency by that amount.
Moreover, since the [0058] transmission 3 is a traction-roller transmission, the amount of sound generated during operation is small compared to the case when a gear-type transmission such as a planetary-gear type transmission us used, and thus it is difficult for a noise problem to occur even when installed near where people live such as near private homes. Particularly, since gears or belts, which generate a lot of noise, are not used in the power transmission system from the propeller 1 to the generator 5, this transmission 3 is very effective in preventing noise.
Moreover, the traction-[0059] roller type transmission 3 is of the wedge-action roller type, so the surface pressures at the points of contact between the driving-force-transmission cylindrical surfaces 34 and driven-side cylindrical surface 46 and drive-side cylindrical surface 33 changes suitably according to the size of the rotation force (torque) that is transmitted from the input shaft 2 to the output shaft 4. Therefore, the rotation force from the propeller 1 can be transmitted to the rotor 6 of the generator 3 with good efficiency even though the rotation force from the propeller 1 changes due to the wind speed. The contact pressures at the radially outer points of contact 53 a, 53 b and the radially inner points of contact 54 a, 54 b rise due to the movement of the movable roller 27 after the propeller 1 starts rotating. Therefore, the rise in rotation resistance of the input shaft 2 of the transmission 3 that occurs as the surface pressure rises does not hinder the starting of rotation of the propeller 1.
Furthermore, since a large speed-up ratio can be obtained by the [0060] transmission 3, it is possible to set a low rpm for the propeller 1, and thus keep the amount of noise generated by the propeller 1 cutting through the wind low.
Next, FIG. 5 shows a second example of the embodiment of the invention. In the case of the first example described above, the [0061] cover 16 of the housing 14 that stores the transmission 3 served the function of covering the opening of the generator case 7. In other words, in the case of the first example, the transmission 3 and generator 5 were constructed as a single unit. However, in the case of this example, the transmission 3 a and generator 5 a have their own independent housing 14 a and generator case 7 a, and are independent from each other. However, the center roller of the transmission 3 a is connected to the tip end of the rotating shaft 19 a of the generator 5 a such that it is made into a single component with the rotating shaft 19 a.
As can be seen in FIG. 1 and FIG. 2, the [0062] center roller 17 of the wedge-action type traction-roller transmission can easily be inserted and removed on the inside of the guide rollers 26 a, 26 b and movable roller 27. Therefore, it is easy to perform the work of assembling the independent transmission 3 a and generator 5 a as shown in FIG. 5. As a result, it is possible to sell a wind-powered generator for home use as a kit, and the person who buys the kit can easily perform the work of assembling the kit.
The construction and function of all other parts are the same as those of the first example and any redundant drawings and explanation will be omitted. [0063]
Next, FIGS. [0064] 6 to 9 show a third example of the embodiment of the invention. In the case of this example, improvements are added to the construction of the first example shown in FIG. 1 to 4 described above in order to obtain the following functions and effects.
1. To reduce the amount of wind caught by the [0065] propeller 1 in a strong wind to reduce the force applied to the components, including the support pole 10a, and to prevent damage to the components.
2. To effectively prevent foreign matter such as dust or dirt in the air from getting into the [0066] transmission 3 b, while at the same time suppressing a rise in rotation resistance to maintain generating efficiency. 3. To improve the generating efficiency of the generator 5 b itself without increasing the size.
The basic construction of this invention, that is, assembling a traction-[0067] roller transmission 3 b in between the propeller 1 and generator 5 b, is the same as that of the first example described using FIGS. 1 to 4, so any redundant explanation of identical parts will be omitted or simplified, and only the features of this example, which are points 1 to 3 described above, will be explained.
First, FIG. 6 will be used to explain the section for obtaining the function and effect of [0068] item 1 above. A rotating bracket 56 is rotatably supported by upper and lower rolling bearings 57, such as a pair of deep-groove ball bearings that freely support radial and axial loads, at the top of a support pole 10 a, which is anchored to the top surface of a base plate 55 that is fastened to a surface such as a roof top. Also, the main unit 9 a of the generating apparatus is supported such that it freely rocks around a horizontal shaft 59 that is located in a support arm 58 that is fastened to the outer peripheral surface at the top of the rotating bracket 56. In order to do that, the horizontal shaft 59 supports the bottom end of a rocking arm 61, which protrudes from the middle in the axial direction of the bottom surface of the casing 60 of the main unit 9 a that surrounds the generator case 7 b, such that the rocking arm 61 can rotate. Also, a seat bracket 63 is fastened to the front end in the axial direction of bottom surface of the casing 60 (end on the side of the propeller 1, or left end in FIG. 6). In the case when the main unit 9 a turns the maximum amount in the counterclockwise direction in FIG. 6 in order for the propeller 1 to most effectively catch the wind, the seat bracket 63 comes in contact with the top surface of the rotating bracket 56 over a wide area as shown in the FIG. 6, so that this seat bracket 63 supports the weight of the main unit 9 a and propeller 1.
On the other hand, when the wind that the [0069] propeller 1 catches becomes strong (during strong wind), the main unit 9 a rocks in the clockwise direction of FIG. 6 around the horizontal shaft 59 and the angle between the center axis of rotation of the propeller 1 and the horizontal direction gradually becomes larger. As a result, the effective area of the propeller 1 that catches the wind is reduced, and together with preventing the rpm of the propeller 1 from becoming excessively high, it prevents excessive force from being applied to the support mechanism of the propeller 1, including the support pole 10 a, and prevents damage to the support mechanism. When the speed of the wind drops, in order that the main unit 9 a automatically returns to the position shown in FIG. 6, a restoration force is applied to the main unit 9 a in a direction to decrease the angle of inclination of the center axis of rotation of the propeller 1 with respect to the horizontal direction. In order to do that, the center of gravity of the section, including the main unit 9 a and propeller 1, that rocks around the horizontal shaft 59 is such that it does not move further backward (toward the right in FIG. 6) than a vertical line that passes through the horizontal shaft 59, or a return spring is located between the main unit 9 a and rotating bracket 56. It is possible to use a tension spring between the front end (left end in FIG. 6) of the main unit 9 a and the rotating bracket 56, or a torsion coil spring that runs between the support arm 58 and the rocking arm 61.
Next, FIG. 7 will be used to explain the section for obtaining the function and effect of [0070] item 2 above. The boss section 37 a that is located in the section that connects to the base end of the input shaft 2 in the center section of the outer ring 32 of the traction-roller transmission 3 b having the same construction as that of the first embodiment shown in FIGS. 1 to 4, and the section in the middle of the input shaft 2 near the base end are rotatably supported by a pair of rolling bearings 40 a, 40 b, that are deep-groove or angular ball bearings, in the support cylinder section 38 a formed in the center section of the main housing 15 a of the housing 14 b that stores the transmission 3 b. Of these two rolling bearings 40 a, 40 b, the load capacity of the rolling bearing 40 a, which is near the propeller 1 and to which a large load is applied for supporting most of the weight of the propeller 1, is larger than the load capacity of the rolling bearing 40 b, which is located on the side of the transmission 3 b and to which only a relatively small load is applied. Furthermore, there is a seal ring 41 located between the inner peripheral surface around the tip end of the support cylindrical section 38 a (left end in FIG. 7) and the outer peripheral surface in the middle of the input shaft 2. Therefore, in the case of this example, the dimension in the axial direction of the support cylindrical section 38 a is larger than the dimension in the axial direction of the support cylindrical section 38 (see FIG. 2) of the first example.
Also, a bank shaped protruding [0071] section 64 is formed around the outer peripheral surface on the tip end of the support cylindrical section 38 a, and the outer diameter of this tip end is greater than the outer diameter in the middle section. On the other hand, there is a connection bracket 65 located on the tip end of the input shaft 2 on the section that protrudes from the support cylindrical section 38 a, so as to connect and fasten the base end of the propeller 1 to the input shaft 2. This connection bracket 65 is fastened to the input shaft 2 by a key joint such that the rotation of the propeller 1 is securely transmitted to the input shaft 2 by way of this connection bracket 65. A cover bracket 66 is fastened using screws to the rear surface (surface on the right sight in FIG. 7) of this connection bracket 65 in the section that surrounds the support cylindrical section 38 a. This cover bracket 66 is generally ring shaped and has a crank-shaped cross section, and has the base end connected and fastened to the connection bracket 65 and the tip end edge coming very close to and facing the middle section of the outer peripheral surface of the support cylindrical section 38 a. Also, this tip end edge and protruding section 64 form a bending labyrinth clearance 67 between the support cylindrical section 38 a and the cover bracket 66. In this example, by forming this kind of labyrinth clearance 67, the amount of foreign matter such as dirt and dust that reaches the section where there is rubbing contact between the inner peripheral edge of the seal ring 41 and the outer peripheral surface of the input shaft 2 is reduced, and thus good seal capability of this rubbing-contact section can be maintained well over a long period of time.
Next, in addition to FIG. 7, FIG. 8 and FIG. 9 will be used to explain the section for obtaining the function and effect of [0072] item 3 above. The generator 5 b that is used in this example is an axial-type slotless generator. In order to construct this generator 5 b, a generator case 7 b is supported and fastened inside the casing 60 by the cover 16 a that separates it from the transmission 3 b. Also, the rotating shaft 19, which also functions as the output shaft 4 of the transmission 3 b, has the base end which is supported in the bottom of the generator case 7 b, and the middle section toward the tip end which is supported inside of a through hole 18 formed in the center section of the cover 16 a, such that they can rotate freely by a rolling bearing 20.
A plurality of circular-shaped [0073] yokes 68 that are made of a magnetic material such as laminated steel plate are located in the middle of the rotating shaft 19 that is rotatably supported inside the center of the generator case 7 b as described above, in the section between the pair of rolling bearings 20 and they are fastened such that the yokes 68 are spaced apart in the axial direction. In order to do this, in this example, the yokes 68 and the circular-shaped spacers 71 that are located between adjacent yokes 68 in the axial direction, are held between a retaining ring 69 that is fastened in the middle toward the base end of the rotating shaft 19 and a nut 70 that screws onto the middle section toward the tip end of the rotating shaft 19. In the example shown in the figure, a partial-cylindrical-shaped sleeve 72 is fitted around the middle section of the rotating shaft 19 and the yokes 68 and spacers 71 fit around this sleeve 72. Also, by running a key 73 between the yokes 68 and rotating shaft 19, the yokes 68 rotate together with the rotating shaft 19.
Also, of these [0074] yokes 68, permanent magnets 74 are attached to the surface on one side in the axial direction (left side in FIG. 7) of all of the yokes 68 except for the yoke nearest the tip end. As shown in FIG. 8, this permanent magnet 74 comprises four quarter-arc-shaped (sector-shaped) elements 75 a, 75 b that are arranged in ring shape. These elements 75 a, 75 b are magnetically oriented in the axial direction (left-right direction in FIG. 7, or front-back direction in FIG. 8), and the direction of magnetic orientation is opposite between adjacent elements 75 a, 75 b in the circumferential direction. Also, the S-poles and N-poles are arranged on the side surface of the tip end of the permanent magnet 74 such that they alternate in circumferential direction.
On the other hand, a plurality of [0075] coil holders 76 are fastened on the inner peripheral surface of the generator case 7 b in the section where the phase in the axial direction is separated from the yokes 68. These coil holders 76 are made into a generally circular-ring shape out of a non-magnetic material such as an aluminum alloy or synthetic resin, so that when the circular spacers 77 are held between a pair of coil holders 76 adjacent to each other in the axial direction, they fit around and are fastened to the inner peripheral surface of the generator case 7 b in the middle section in the axial direction. In this state, the coil holders 76 are located between adjacent yokes 68 and permanent magnets 74 such that they are close to and face (in a non-contact state) both members 68, 74.
As shown in FIG. 9, the [0076] coils 78 are arranged on one of the side surfaces in the axial direction (left side surface in FIG. 7) of the coil holder 76, which is fastened on the inside peripheral surface of the generator case 7 b in this way, such that a plurality of coils 78 (six coils in the example in the figure) are arranged on each coil holder 76 and spaced uniformly from each other in the circumferential direction on an arc centered around the rotating shaft 19. The conducting wires of each of the coils 78 are wound around the inside of circular-shaped concave bobbins 79 that are formed in one side surface in the axial direction of each coil holder 76, such that they come close to and face the other side surface in the axial direction (right side surface in FIG. 7) of the yokes 68.
When the [0077] propeller 1 catches the wind and the rotating shaft 19 rotates by way of the transmission 3 b, the yokes 68 and the permanent magnets 74 that are supported by the yokes 68 rotate. As a result, the coils 78 cross the magnetic flux coming from the permanent magnets 74, and electric power is induced in these coils 78. This electric power is sent to the wiring in the rotating bracket 56 by way of a flexible cord (not shown in the figure), and by further sending the power by way of a slip ring (not shown in the figure) to electric-power- distribution equipment located in a unit that is fixed to the top of the base plate 55 for example, the electric power generated by the generator 5 b can be obtained.
In the case of this example, an axial-type slotless generator is used as the [0078] generator 5 b, so construction can be more compact and a larger amount of electric power can be obtained than when a radial-type slotless generator is used. These points will be explained with reference to FIGS. 10 to 13.
FIG. 10 shows a typical slotless generator in which the permanent magnet faces the coil in the radial direction. In this [0079] generator 80, the outer peripheral surface of a permanent magnet 81 that is fastened around the rotating shaft 19 faces the inner peripheral surface of a coil 84 that is supported around the inner peripheral surface of the generator case 82 by way of the stator 83. In the case of a slotless generator, it is possible to prevent the occurrence of cogging due to the existence of slots, which are areas where the yoke is not continuous, and thus operation is more stable than in the case of a typical brushless generator.
It is thought that the amount of electrical power generated by this kind of radial-type slotless generator can be increased by increasing the diameters of the [0080] permanent magnet 81 a, the generator case 82 a, stator 83 a and coil 84 a as shown in FIG. 11, or by lengthening the dimensions in the axial direction of the permanent magnet 81 b, the generator case 82 b, stator 83 b and coil 84 b as shown in FIG. 12. However, in the case of construction having an increased diameter as shown in FIG. 11, not only does the outer diameter of the generator 80 a increase, but it also becomes easier for the permanent magnet 81 a to become damaged by the large centrifugal force that occurs during operation. Also, in the case of lengthening the dimensions in the axial direction as shown in FIG. 12, not only does the length of the generator 80 b become longer, but it becomes difficult to keep the gap between the outer peripheral surface of the permanent magnet 81 b and the inner peripheral surface of the coil 84 b small, and thus it is easy for the generating efficiency to drop. It is thought that by arranging three generators 80 in series in the axial direction as shown in FIG. 13 it is possible to prevent the drop in efficiency that occurs with these kinds of changes in dimensions. However, when construction as shown in FIG. 13, wasted space occurs between adjacent generators 80, and the overall length in the axial direction increases even more. On the other hand, with the axial-type slotless generator that is used in the third example shown in FIGS. 6 to 9, it is possible to maintain sufficient power generation without particularly increasing the size.
The axial-type slotless generated described above has good generating efficiency and requires only a small driving torque, so it is possible to obtain the required power generation in the case when a wedge-action type traction-roller transmission is assembled between propeller and generator to rotate the [0081] rotating shaft 19 at high speed, as well as in the case when with no transmission used, the propeller is connected directly to the generator. Furthermore, since it is possible to maintain a certain amount of power generation even when the driving speed of the generator is kept low, it is possible to keep the amount of noise generated by the generator low, even in the case of using a gear-type transmission. Therefore, in the case of using an axial-type slotless generator (its use is preferred), the problems mentioned above can be solved even when not using a wedge-action type traction-roller transmission.
Industrial Applicability: [0082]
This invention, constructed and functioning as described above, provides a wind-powered generating apparatus that can be easily installed in a typical home or small business site, and that is capable of operating with low noise and good generating efficiency. A mechanism similar to that of the wind-powered generating apparatus of this invention can also be used in the driving mechanism of a small hydroelectric generator that uses the water current of a small river or irrigation canal. [0083]

Claims

1. A wind-powered generating apparatus comprising a propeller for receiving wind and being turned by the wind, a transmission having an input shaft and an output shaft, such that the propeller is connected to the end of the input shaft, and a generator driven by the output shaft of the transmission to rotate, and where the transmission is a wedge-action type traction-roller transmission, the transmission comprising an outer ring rotating as the input shaft rotates and having an inner peripheral surface formed with a drive-side cylindrical surface, a center roller rotating together with the output shaft and having an outer peripheral surface formed with a driven-side cylindrical surface, such that an annular space is formed between the driven-side cylindrical surface and the driving-side cylindrical surface, a plurality of support shafts provided in the annular space in parallel with the center roller, and a plurality of intermediate rollers rotatably supported by the support shafts and having an outer peripheral surface formed with a drive-force-transmission cylindrical surface, wherein by making the center of the center roller eccentric with the center of the input shaft and outer ring, the radial width size of the annular space is uneven in the circumferential direction, wherein one of the intermediate rollers is a movable roller which is movable in the circumferential direction in the annular space with the remaining intermediate rollers being a guide roller, and wherein when the center roller and outer ring rotate in a predetermined direction at a speed corresponding to a transmission rate between the output shaft and the input shaft, the intermediate roller for the movable roller can be moved toward the narrow width portion in the annular space.

2. The wind-powered generating apparatus of claim 1, wherein the transmission and the generator are enclosed in a main unit which is supported in a bracket so as to rock around a horizontal axis, the bracket being rotatably supported around a vertical axis, and the main unit being provided with a restoring force in a direction such that the axis of rotation center of the propeller is made smaller in tilting angle with reference to the horizontal direction.

3. The wind-powered generating apparatus of claim 1, wherein the generator is an axial-type slotless generator comprising a generator case, a rotating shaft rotatably supported in the generator case to rotate with the output shaft of the transmission, a plurality of yokes fixed to the outer peripheral surface of the rotating shaft with a space in the axial direction and made of a magnetic material, a permanent magnet supported by an axial side surface of the yokes and having S-poles and N-poles alternately arranged in a circumferential, a plurality of coil holders fixed to the inner peripheral surface of the generator case at a section where the phase with respect to the axial direction is separated from the yokes, and coils each facing the permanent magnet and supported by an axial side surface of the coil holders.

4. A wind-powered generating apparatus comprising a propeller that catches the wind to rotate, and a generator that is operated and driven by the propeller; and where the generator is an axial-type slotless generator that comprises: a generator case; a rotating shaft that is supported inside the generator case such that it can freely rotate together with the output shaft of the transmission; a plurality of yokes made of a magnetic material and that are fastened at intervals in the axial direction around the outer peripheral surface of the rotating shaft; permanent magnets that are supported by the sides in the axial direction of the yokes and which are arranged such that the S-poles and N-poles alternate in the circumferential direction; a plurality of coil holders that are fastened to the inner peripheral surface of the generator case in the section where the phase in the axial direction is away from the yokes; and a plurality of coils held on each of the sides in the axial direction of each coil holder such that they face the permanent magnets.

5. The wind-powered generating apparatus of claim 2, wherein the generator is an axial-type slotless generator comprising a generator case, a rotating shaft rotatably supported in the generator case to rotate with the output shaft of the transmission, a plurality of yokes fixed to the outer peripheral surface of the rotating shaft with a space in the axial direction and made of a magnetic material, a permanent magnet supported by an axial side surface of the yokes and having S-poles and N-poles alternately arranged in a circumferential, a plurality of coil holders fixed to the inner peripheral surface of the generator case at a section where the phase with respect to the axial direction is separated from the yokes, and coils each facing the permanent magnet and supported by an axial side surface of the coil holders.