U.S. patent application number 10/567613 was filed with the patent office on 2006-09-14 for speed reducer for use in yaw drive apparatus for wind power generation apparatus, and yaw drive method and apparatus for wind power generation apparatus using the speed reducer.
Invention is credited to Osamu Nohara, Sadayuki Tanabe, Katsuhiko Yokoyama.
Application Number | 20060205554 10/567613 |
Document ID | / |
Family ID | 34139873 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060205554 |
Kind Code |
A1 |
Nohara; Osamu ; et
al. |
September 14, 2006 |
Speed reducer for use in yaw drive apparatus for wind power
generation apparatus, and yaw drive method and apparatus for wind
power generation apparatus using the speed reducer
Abstract
A speed reducer and a yaw drive apparatus for a wind power
generation apparatus, where the speed reducer has high efficiency
and a short axial length, and suitable for the yaw drive apparatus.
The speed reducer has three stages for speed reduction. The total
reduction gear ratio of a first stage speed reducing portion 10 and
a second speed reducing portion 20 is set to 1/6 to 1/60, and a
third stage speed reducing portion 30 is constructed from an
eccentric oscillating-type speed reduction mechanism having an
internal gear member 32, external gears 34, crankshafts 35, and a
carrier 37. The reduction gear ratio of the eccentric
oscillating-type speed reduction mechanism is set to 1/50 to 1/140,
and the total reduction gear ratio of the speed reducer is set to
1/1000 to 1/3000. A yaw drive method and the yaw drive apparatus
can reduce noise, and the yaw drive apparatus is inexpensive and
reduced in size.
Inventors: |
Nohara; Osamu; (Gifu,
JP) ; Yokoyama; Katsuhiko; (Gifu, JP) ;
Tanabe; Sadayuki; (Gifu, JP) |
Correspondence
Address: |
AKIN GUMP STRAUSS HAUER & FELD L.L.P.
ONE COMMERCE SQUARE
2005 MARKET STREET, SUITE 2200
PHILADELPHIA
PA
19103
US
|
Family ID: |
34139873 |
Appl. No.: |
10/567613 |
Filed: |
August 11, 2004 |
PCT Filed: |
August 11, 2004 |
PCT NO: |
PCT/JP04/11786 |
371 Date: |
February 8, 2006 |
Current U.S.
Class: |
475/179 |
Current CPC
Class: |
F03D 7/0204 20130101;
F05B 2270/32 20130101; Y02E 10/722 20130101; F05B 2270/321
20130101; Y02E 10/723 20130101; F05B 2260/4031 20130101; F05B
2260/90 20130101; F05B 2270/1095 20130101; Y02E 10/72 20130101;
F05B 2270/329 20130101; F16H 1/32 20130101 |
Class at
Publication: |
475/179 |
International
Class: |
F16H 1/32 20060101
F16H001/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 12, 2003 |
JP |
2003-292066 |
Sep 19, 2003 |
JP |
2003-329073 |
Sep 19, 2003 |
JP |
2003-328965 |
Nov 14, 2003 |
JP |
2003-385529 |
Nov 17, 2003 |
JP |
2003-386086 |
Claims
1. A speed reducer used in a yaw drive apparatus of a wind power
generation apparatus, comprising: a first stage speed reducing
portion, a second stage speed reducing portion connected to the
first speed reducing portion, and a third stage speed reducing
portion, wherein a total reduction gear ratio of a first stage
speed reducing portion and a second speed reducing portion is set
to 1/6 to 1/60, the third stage speed reducing portion is
constructed by an eccentric oscillating type speed reduction
mechanism comprising an internal gear member in which internal
teeth are formed at the internal periphery thereof, a plurality of
external gears which are received in the internal gear member,
which have external teeth engaged with the internal teeth and
having number of teeth slightly less than that of the internal
teeth at the external periphery thereof, and which are disposed in
parallel to each other in the axial direction, a plurality of crank
shafts which are rotatably inserted into the plurality of external
gears, and which are connected to the second stage speed reducer
and rotate to eccentrically rotate the plurality of external gears,
and a carrier which rotatably supports both ends of the crank
shafts, and a reduction gear ratio of the eccentric
oscillating-type speed reduction mechanism is set to 1/50 to 1/140,
and the total reduction gear ratio of the speed reducer is set to
1/1000 to 1/3000.
2. The speed reducer used in the yaw drive apparatus of the wind
power generation apparatus according to claim 1, wherein the first
stage speed reducing portion is constructed by a planetary speed
reduction mechanism including an input sun gear, a plurality of
planetary gears engaged with the input sun gear at the periphery of
the input sun gear, an internal gear member having internal teeth
engaged with the plurality of the planetary gears at the periphery
of the plurality of the planetary gears, and a carrier rotatably
supporting the plurality of planetary gears, and the second stage
speed reducing portion is constructed by a spur gear type speed
reduction mechanism including an input spur gear connected to the
carrier of the planetary speed reduction mechanism, and a spur gear
engaged with the input spur gear.
3. The speed reducer used in the yaw drive apparatus of the wind
power generation apparatus according to claim 1, wherein the first
stage speed reducing portion is constructed by a spur gear type
speed reduction mechanism including a first input spur gear, and a
first spur gear engaged with the first input spur gear, and the
second stage speed reducing portion is constructed by spur gear
type speed reduction mechanism including a second input spur gear
connected to the first spur gear, and a second spur gears engaged
with the second input spur gear.
4. A yaw drive apparatus of a wind power generation apparatus using
the speed reducer according claim 1, wherein an output shaft of a
motor is connected to an input part of a first stage speed reducing
portion, and an output part of an eccentric oscillating-type speed
reduction mechanism is provided with external teeth engaged with a
ring gear of a tower.
5. A yaw drive method of a wind power generation apparatus, in
which a second gear engaged with a first gear attached to one of
tower or a wind power generation unit supported to the upper end of
the tower so as to be capable of yawing and supported to a tower or
to the upper end of the tower is rotated by a drive motor attached
to the other of the tower or the wind power generation unit for
yawing the wind power generation unit, wherein a drive energy,
which is supplied to the drive motor for a predetermined time from
when the supply of the drive energy to the drive motor begins to
start, is made to be smaller than the drive energy supplied to the
drive motor in a common yawing.
6. The yaw drive method of a wind power generation apparatus
according to claim 5, wherein the drive energy, which is supplied
to the drive motor for a predetermined period just before a point
of time at which the supply of the drive energy to the drive motor
is stopped to the point of time at which the supply of the drive
energy is stopped, is made to be smaller than the drive energy
supplied to the drive motor in a common yawing, and at the same
time a predetermined value of braking torque is applied to the
drive motor by the braking means after the supply of the drive
energy to the drive motor is stopped.
7. The yaw drive method of a wind power generation apparatus
according to claim 5, wherein a predetermined value of braking
torque is applied to the drive motor by the braking means after the
passage of a predetermined time from when the supply of the drive
energy to the drive motor is stopped.
8. A yaw drive apparatus of a wind power generation apparatus, the
yaw drive apparatus, comprising: a first gear attached to one of
tower and a wind power generation unit supported to the upper end
of the tower so as to be capable of yawing, a second gear engaged
with the first gear, a drive motor attached the other of the tower
or the wind power generation unit, and rotates the second gear when
the drive energy is supplied thereto, thereby yawing the wind power
generation unit, and a reduction means for making a drive energy,
which is supplied to the drive motor for a predetermined time from
when the supply of the drive energy to the drive motor begins to
start, smaller than the drive energy supplied to the drive motor in
a common yawing.
9. The yaw drive apparatus of the wind power generation apparatus
according to claim 8, wherein the drive energy which is supplied to
the drive motor for a predetermined period just before the supply
of the drive energy until the drive motor is stopped to the point
of time at which the supply of the drive energy is stopped, is made
smaller than the drive energy supplied to the drive motor in a
common yawing by the reduction means, and wherein the yaw drive
apparatus further comprises a braking means for applying a
predetermined value of braking torque to the drive motor after the
supply of the drive energy to the drive motor is stopped.
10. The yaw drive apparatus of the wind power generation apparatus
according to claim 9, wherein the drive motor and the second gear
are plurally provided, and wherein drive energy made to be small is
supplied to apart of the drive motor by the reduction means even
after the yawing of the wind power generation unit is stopped to
rotate the second gear, such that the backlash between the teeth of
the first gear and the teeth of the second gear is removed.
11. The yaw drive apparatus of the wind power generation apparatus
according to claim 8, wherein when the drive motor is composed of a
fluid motor, a pair of supply/discharge passages which supply and
discharge the fluid to and from the fluid motor is connected to
each other by a connection passage, and a throttle is interposed in
the connection passage, such that the rotational speed of the fluid
motor when it performs a pump operation is controlled by the
throttle.
12. The yaw drive apparatus of the wind power generation apparatus
according to claim 8, wherein when the drive motor is composed of a
fluid motor, a pair of supply/discharge passages which supply and
discharge the fluid to and from the fluid motor is connected to
each other by a connection passage, and a relief valve, which is
switched into on-state when a pressure in one of the
supply/discharge passages is raised to a value higher than a
predetermined value, is interposed in the connection passage, such
that the torque control of the fluid motor is performed by the
relief valve when the fluid motor performs the pump operation.
13. The yaw drive apparatus of the wind power generation apparatus
according to claim 9, further comprising: an anemometer for
measuring a wind direction, wherein the drive motor is released
from the braking caused by the braking means when the wind velocity
measured by the anemometer is a predetermined value or more.
14. A yaw drive method of a wind power generation apparatus, in
which a pinion, which is engaged with a ring-shaped internal gear
attached to one of a tower or a wind power generation unit
supported to the upper end of the tower so as to be capable of
yawing, is rotated by a drive motor attached to the other of the
tower or the wind power generation unit for yawing the wind power
generation unit, wherein a drive energy, which is supplied to the
drive motor for a predetermined time from when the supply of the
drive energy to the drive motor begins to start, is made smaller
than the drive energy supplied to the drive motor in a common
yawing.
15. The yaw drive method of a wind power generation apparatus
according to claim 14, wherein the drive energy, which is supplied
to the drive motor for a predetermined period just the supply of
the drive energy to the drive motor is stopped until the supply of
the drive energy is stopped, is made to be smaller than the drive
energy supplied to the drive motor in a common yawing, and at the
same time a predetermined value of braking torque is applied to the
drive motor by the braking means after the supply of the drive
energy to the drive motor is stopped.
16. The yaw drive method of a wind power generation apparatus
according to claim 14, wherein a predetermined value of braking
torque is applied to the drive motor by the braking means after the
a predetermined time from when the supply of the drive energy to
the drive motor is stopped.
17. A yaw drive apparatus of a wind power generation unit, the yaw
drive apparatus comprising: a ring-shaped internal gear attached to
one of a tower or a wind power generation unit supported to the
upper end of the tower so as to be capable of yawing, a pinion
engaged with the internal gear, a drive motor attached the other of
the tower or the wind power generation unit, and rotates the pinion
when the drive energy is supplied thereto, thereby yawing the wind
power generation unit, and a reduction means a drive energy, which
is supplied to the drive motor for a predetermined time from when
the supply of the drive energy to the drive motor begins to start,
is smaller than the drive energy supplied to the drive motor in a
common yawing.
18. The yaw drive apparatus of the wind power generation unit
according to claim 17, wherein the drive energy, which is supplied
to the drive motor for a predetermined period just before the
supply of the drive energy to the drive motor is stopped until the
supply of the drive energy is stopped, is made smaller than the
drive energy supplied to the drive motor in a common yawing by the
reduction means, and wherein the yaw drive apparatus further
comprises a braking means for applying a predetermined value of
braking torque to the drive motor after the supply of the drive
energy to the drive motor is stopped.
19. The yaw drive apparatus of the wind power generation unit
according to claim 18, wherein the drive motor and the pinion gear
are plurally provided, and wherein drive energy made to be small is
supplied to a part of the drive motor by the reduction means even
after the yawing of the wind power generation unit is stopped to
rotate the pinion, such that the backlash between the teeth of the
pinion and the teeth of the internal gear is removed.
20. The yaw drive apparatus of the wind power generation unit
according to claim 17, wherein when the drive motor is composed of
a fluid motor, a pair of supply/discharge passages which supply and
discharge the fluid to and from the fluid motor is connected to
each other by a connection passage, and a throttle is interposed in
the connection passage, such that the rotational speed of the fluid
motor when it performs a pump operation is controlled by the
throttle.
21. The yaw drive apparatus of the wind power generation unit
according to claim 17, wherein when the drive motor is composed of
a fluid motor, a pair of supply/discharge passages which supply and
discharge the fluid to and from the fluid motor is connected to
each other by a connection passage, and a relief valve, which is
switched into on-state when a pressure in one of the
supply/discharge passages is raised to a value higher than a
predetermined value, is interposed in the connection passage, such
that the torque control of the fluid motor is performed by the
relief valve when the fluid motor performs the pump operation.
22. The yaw drive apparatus of the wind power generation unit
according to claim 18, further comprising: an anemometer for
measuring a wind direction, wherein the drive motor is released
from the braking caused by the braking means when the wind velocity
measured by the anemometer is a predetermined value or more.
Description
TECHNICAL FIELD
[0001] The present invention relates to a speed reducer for use in
a yaw drive apparatus which rotates a wind power generation unit of
a wind power generation apparatus in a substantially horizontal
plane, and a yaw drive method and an apparatus for wind power
generation apparatus using the speed reducer.
BACKGROUND ART
[0002] In general, the yaw drive apparatus of the wind power
generation apparatus rotates a windmill power generation unit about
a tower according to a wind in order that blades of the wind power
generation apparatus can receive the wind, and rotates a ring gear
provided at the tower.
[0003] The yaw drive apparatus is generally constructed by a
general-purpose induction motor (the number of rotations is 1000 to
1800 rpm) and a plurality of reducing mechanism (the total
reduction gear ratio is 1/1000 to 1/3000).
[0004] Most conventional speed reducers for use in the yaw drive
apparatus of the windmill power generation apparatus use a speed
reducer including five stage-planetary speed reduction mechanisms,
for obtaining the high gear reduction ratio. The planetary speed
reduction mechanism includes an input sun gear, a plurality of
planetary gears engaged with the input sun gear at the periphery of
the input sun gear, an internal gear member having internal teeth
engaged with the plurality of the planetary gears at the periphery
of the plurality of the planetary gears, and a carrier rotatably
supporting the plurality of planetary gears. The total reduction
gear ratio is about 77%
(95%.times.95%.times.95%.times.95%.times.95% at each stage=about
77%).
[0005] The applicant of the present invention has proposed to
construct the speed reducer as three stage speed reduction
mechanism constituted by a first speed reducing portion, a second
speed reducing portion connected to the first speed reducing
portion, and an eccentric oscillating-type speed reduction
mechanism connected to the second speed reducing portion (refer to
JP-A-2003-84300).
[0006] Further, an example of the conventional yaw drive method and
apparatus of the wind power generation apparatus having the
construction to be described is disclosed in JP-A-2001-289149.
[0007] The above-described yaw drive apparatus including a first
gear connected to the upper end of the tower, a second gear engaged
with the first gear, a motor which is attached to the wind power
generation unit capable of yawing, supported at the upper end of
the tower and drivingly rotates the second gear for yawing the wind
power generation unit, a hydraulic brake including an
electromagnetic brake attached to the motor and using a friction
plate, a brake disk fixed to the upper end of the tower, and a
frictional-fixing type brake shoe which is provided to the wind
power generation unit and interposes the brake disk in it using the
hydraulic driving.
[0008] When the wind power generation unit is yawed by the motor,
the electro-magnetic brake and the hydraulic brake are turned into
a non-braking state simultaneously with the start-up of the
electrification to the motor, so that the motor and the wind power
generation unit is released from the braking. On the other hand,
when the yawing of the wind power generation unit is stopped, the
electro-magnetic brake and the hydraulic brake are turned into the
braking state simultaneously with the stoppage of the
electrification to the motor, so that the motor and the wind power
generation unit are provided with the braking torque.
[0009] However, the maintenance of the former speed reducer
including five stage-planetary speed reduction mechanisms was not
good due to the long total length and the large capacity. Further,
when the speed reducer is operated at a low temperature of
-20.degree. C. or less, the stirring resistance of a lubricant
becomes large due to the five stage reduction, and a motor with a
large output is needed for compensating the loss of the stirring
resistance.
[0010] In the latter speed reducer including the three stage speed
reducing portions, the optimum reduction gear ratio for obtaining
high efficiency for yaw drive apparatus was not proposed.
[0011] In consideration of the above-described situation, it is an
object of the present invention to provide a speed reducer which is
provided with an optimum speed distribution for a yaw drive
apparatus, has high efficiency and a short axial length, and is
suitable for the yaw drive apparatus. Further, it is another object
of the present invention to provide a yaw drive apparatus of a wind
power generation apparatus which is highly efficient and is compact
in size.
[0012] Further, in the conventional yaw drive method and apparatus
of the wind power generation apparatus, since the braking against
the motor is terminated when the electrification to the motor
begins to start, the rotational drive torque of the motor is
transferred to the second gear as it is, so that it rotates rapidly
the second gear. However, since the wind power generation unit has
a large inertial mass, it cannot rotate by following the second
gear. As a result, the teeth of the second gear cause a significant
impact on the first gear. Therefore, the teeth of the first and
second gear may be damaged at the start-up of the yawing of the
wind power generation unit, or a loud noise occurs. Further,
considering the structural features, the strength of the first and
second gears needs to be increased for the impact resistance, so
that the apparatus becomes expensive and large in size.
[0013] On the other hand, when the electrification to the motor is
stopped, since the electromagnetic brake starts applying the
braking torque to the motor, therefore, the rotation of the second
gear is rapidly stopped. However, since the wind power generation
unit is apt to rotate continuously at the same rotational speed,
the teeth of the first gear cause a significant impact on the teeth
of the second gear. Therefore, the teeth of the first and second
gear may be damaged even when the yawing of the wind power
generation unit is stopped, or a loud noise occurs. Further, the
strength of the first and second gears needs to be increased for
the impact resistance as described above, thus the apparatus
becomes expensive and large in size.
[0014] Therefore, it is an object of the present invention to
provide a yaw drive method and apparatus of the wind power
generation apparatus in which the impact at the start-up of the
supply of the drive energy to the drive motor is suppressed,
whereby the damage on the teeth and the noise are reduced, at the
same time, the size is reduced at a low cost.
DISCLOSURE OF THE INVENTION
[0015] The present invention provides a reducer constituted by a
first stage speed reducing portion, a second stage speed reducing
portion connected to the first speed reducing portion, and a third
stage speed reducing portion. Further, the total reduction gear
ratio of a first stage speed reducing portion and a second speed
reducing portion is set to 1/6 to 1/60. Further, the third stage
speed reducing portion is constructed by an eccentric oscillating
type speed reduction mechanism including an internal gear member in
which internal teeth are formed at the internal periphery thereof,
a plurality of external gears which are received in the internal
gear member, which have external teeth engaged with the internal
teeth and having number of teeth slightly less than that of the
internal teeth at the external periphery thereof, and which is
disposed in parallel to each other in the axial direction, a
plurality of crank shafts which are rotatably inserted into the
plurality of external gears, and which are connected to the second
stage speed reducer and rotates to eccentrically rotate the
plurality of external gears, and a carrier which rotatably supports
both ends of the crank shafts. Further, a reduction gear ratio of
the eccentric oscillating-type speed reduction mechanism is set to
1/50 to 1/140, and the total reduction gear ratio of the speed
reducer is set to 1/1000 to 1/3000. Therefore, it is possible to
provide the speed reducer which is suitable for the yaw drive
apparatus of the wind power generation apparatus, and has high
efficiency and a short axial length.
[0016] Further, the first stage speed reducing portion of the speed
reducer is constructed by a planetary speed reduction mechanism
including an input sun gear, a plurality of planetary gears engaged
with the input sun gear at the periphery of the input sun gear, an
internal gear member having internal teeth engaged with the
plurality of the planetary gears at the periphery of the plurality
of the planetary gears, and a carrier rotatably supporting the
plurality of planetary gears. Further, the second stage speed
reducing portion of the speed reducer is constructed by a spur gear
type speed reduction mechanism including an input spur gear
connected to the carrier of the planetary speed reduction
mechanism, and a spur gear engaged with the input spur gear.
Therefore, it is possible to provide the speed reducer which is
suitable for the yaw drive apparatus of the wind power generation
apparatus, and has high efficiency and a short axial length.
[0017] Further, the first stage speed reducing portion of the speed
reducer is constructed by a spur gear type speed reduction
mechanism including a first input spur gear, and a first spur gear
engaged with the first input spur gear, and the second stage speed
reducing portion of the speed reducer is constructed by spur gear
type speed reduction mechanism including a second input spur gear
connected to the first spur gear, and a second spur gears engaged
with the second input spur gear. Therefore, it is possible to
provide the speed reducer which is suitable for the yaw drive
apparatus of the wind power generation apparatus, and has high
efficiency and a short axial length.
[0018] Further, the yaw drive apparatus of the wind power
generation apparatus according to the present invention uses the
above-described highly efficient speed reducer. An output shaft of
a motor is connected to an input part of a first stage speed
reducing portion, and an output part of an eccentric
oscillating-type speed reduction mechanism is provided with
external teeth engaged with a ring gear of a tower. Therefore, it
is possible to provide the yaw drive apparatus of the wind power
generation apparatus, which is highly efficient and is small in
size.
[0019] Further, there is provided a yaw drive method of a wind
power generation apparatus, in which a second gear engaged with a
first gear attached to one of a tower or a wind power generation
unit supported to the upper end of the tower so as to be capable of
yawing is rotated by a drive motor attached to the other of the
tower or the wind power generation unit for yawing the wind power
generation unit. A drive energy, which is supplied to the drive
motor for a predetermined time from when the supply of the drive
energy to the drive motor begins to start, is made to be smaller
than the drive energy supplied to the drive motor in a common
yawing.
[0020] Further, there is provided a yaw drive apparatus of a wind
power generation apparatus. The yaw drive apparatus includes a
first gear attached to one of a tower or a wind power generation
unit supported to the upper end of the tower so as to be capable of
yawing, a second gear engaged with the first gear, a drive motor
attached to the other of the tower or the wind power generation
unit, and rotates the second gear when the drive energy is
supplied, thereby yawing the wind power generation unit. The
reduction means makes a drive energy, which is supplied to the
drive motor for a predetermined time from when the supply of the
drive energy to the drive motor begins to start, smaller than the
drive energy supplied to the drive motor in a common yawing.
[0021] Further, there is provided a yaw drive method of a wind
power generation apparatus, in which a pinion, which is engaged
with a ring-shaped internal gear attached to one of a tower or a
wind power generation unit supported to the upper end of the towe
so as to be capable of yawingr, is rotated by a drive motor
attached to the other of the tower or the wind power generation
unit for yawing the wind power generation unit. A drive energy,
which is supplied to the drive motor for a predetermined time from
when the supply of the drive energy to the drive motor begins to
start, is made smaller than the drive energy supplied to the drive
motor in a common yawing.
[0022] Further, there is provided a yaw drive apparatus of a wind
power generation unit. The yaw drive apparatus includes a
ring-shaped internal gear attached to one of tower or a wind power
generation unit supported to the upper end of the tower so as to be
capable of yawing and supported to a tower or to the upper end of
the tower, a pinion engaged with the internal gear, a drive motor
attached the other of the tower or the wind power generation unit,
and rotates the pinion when the drive energy is supplied, thereby
yawing the wind power generation unit, and a reduction means that
reduces a drive energy, which is supplied to the drive motor for a
predetermined time from when the supply of the drive energy to the
drive motor begins to start, is smaller than the drive energy
supplied to the drive motor in a common yawing.
ADVANTAGES OF THE INVENTION
[0023] According to the present invention, it is possible to
provide a speed reducer which has high efficiency and a short axial
length, and is suitable for the yaw drive apparatus. Further, it is
possible to provide a yaw drive apparatus of a wind power
generation apparatus which is highly efficient and is compact in
size.
[0024] Further, when the wind power generation unit is yawed by a
drive motor, the drive energy is supplied to the drive motor. At
this time, since the drive energy, which is supplied to the drive
motor from when the supply of the drive energy to the drive motor
begins to start, is made to be smaller than the drive energy
supplied to the drive motor in a common yawing by the reduction
means, the rotational drive torque applied to the second gear from
the drive motor at the start-up of the rotation has an energy
corresponding to the small drive energy. As a result, the impact
between the teeth of the first gear and the second gear is reduced
at the time of the start-up of the rotation of the second gear,
whereby it is possible to reduce the damage on the teeth of the
first and second gears and noise, and to make the apparatus small
in size at a low price. At this state, after a predetermined time,
the rotational speed of the drive motor increases to some degree.
After that, however, the drive motor is provided with the drive
energy in common yawing and the yawing of the wind power generation
unit is performed.
[0025] Further, when the yawing of the wind generation unit is
stopped, the drive energy, which is supplied to the drive motor for
a predetermined period just before the supply of the drive energy
to the drive motor is stopped to the point of time at which the
supply of the drive energy is stopped, is made smaller than the
drive energy supplied to the drive motor in a common yawing, and
the rotary power applied to the wind power generation unit from the
drive motor for the above-described period is made small, the
rotational speed of the wind power generation unit decreases
gradually due to the frictional resistance or gyroscopic effect of
the rotor-head or the like for the above-described period. In this
way, in cases where the rotational speed decrease, and a
predetermined value of braking torque is applied by the braking
means after the supply of the drive energy to the drive motor is
stopped, the impact between the teeth of the first gear and the
teeth of the second gear is reduced, whereby it is possible to
reduce the damage on the teeth of the first and second gear and
noise, and to make the apparatus small in size at a low price.
[0026] Further, when the yawing of the wind power generation unit
is stopped, the supply of the drive energy to the drive motor is
stopped. However, since a predetermined value of braking torque is
applied to the drive motor by the braking means after a
predetermined time from when the supply of the drive energy to the
drive motor is stopped, the rotational speed of the wind power
generation unit gradually decreases due to the frictional
resistance or gyroscopic effect of the rotor-head or the like for a
predetermined time from when the supply of the drive energy is
stopped. Further, since the above-described braking torque is
applied to the drive motor from the braking means when the
rotational speed decreases in this way, the impact between the
teeth of the first gear and the teeth of the second gear is
reduced, whereby it is possible to reduce the damage on the teeth
of the first and second gear and noise, and to make the apparatus
small in size at a low price.
[0027] Further, since it is possible to remove the backlash between
the teeth of the first gear and the teeth of the second gear, the
impact between the teeth of the first gear and the teeth of the
second gear can be reduced more effectively.
[0028] Further, during the stoppage of the driving of the fluid
motor, an excessive wind load of a gust or the like acts on the
wind power generation unit, so that the wind power generation unit
rotates, whereby the fluid motor may perform a pump operation.
However, according to an aspect of the invention, it is possible to
prevent the fluid motor and the wind power generation unit from
being rotated at a high speed.
[0029] Further, the fluid motor may perform the pump operation due
to the above-described reason. However, at this time, the fluid
braking force is applied to the fluid motor by back pressure, so
that the rotation of the fluid motor can be restricted, whereby it
is possible to omit a hydraulic pressure brake constituted by a
brake disk fixed to the upper end of the tower and frictional
fixing type brake shoe in which the brake disk is interposed, which
is necessary to fix the conventional wind power generation
unit.
[0030] For this reason, the drive motor rotate while receiving the
braking force from the brake means and may adversely affect to the
apparatus, but this case can be prevented.
[0031] Further, when the wind power generation unit is yawed by the
drive motor, the drive energy is supplied to the motor. However,
since the start-up braking torque is applied to the drive motor by
the braking means from when the supply of the drive energy to the
drive motor begins to start, the rotational drive torque obtained
by subtracting the start-up braking torque from the output drive
torque of the drive motor is applied to the second gear at a
reduced state. Here, since the start-up braking torque has a
predetermined value lower than the maximum drive torque of the
drive motor, the second gear can rotate for yawing the wind power
generation unit. However, since the rotational drive torque at this
time has a small value obtained from the above-described
subtraction, and the rotational speed of the second gear is reduced
by the start-up braking torque, an impact between the teeth of the
first gear and the teeth of the second gear is reduced, whereby it
is possible to reduce the damage on the teeth of the first and
second gears or noise, and to make the apparatus small in size at a
low price. After a short predetermined time passes from this state,
the rotational speed of the drive motor increases to some degree.
However, at this point of time, the application of the start-up
braking torque is terminated and the yawing of the wind power
generation unit is performed.
[0032] Further, when the yawing of the wind power generation unit
is stopped, the supply of the drive energy to the drive motor is
stopped. However, since a predetermined value of the final braking
torque is applied to the drive motor by the braking means after the
passage of a predetermined time from when the supply of the drive
energy to the drive motor is stopped, the rotational speed of the
wind power generation unit decreases gradually due to the
frictional resistance or gyroscopic effect of the rotor-head or the
like for a predetermined time from when the supply of the drive
energy is stopped. Further, since the above-described final braking
torque is applied to the drive motor from the braking means at the
point of time at which the rotational speed decreases in this way,
the impact between the teeth of the first gear and the teeth of the
second gear is reduced, whereby it is possible to reduce the damage
on the teeth of the first and second gear and noise, and to make
the apparatus small in size at a low price.
[0033] when the yawing of the wind generation unit is stopped, the
drive energy, which is supplied to the drive motor for a
predetermined period just before a point of time at which the
supply of the drive energy to the drive motor is stopped to the
point of time at which the supply of the drive energy is stopped,
is made smaller than the drive energy supplied to the drive motor
in a common yawing, and the rotary power applied to the wind power
generation unit from the drive motor for the above-described period
is made small, the rotational speed of the wind power generation
unit gradually decreases due to the frictional resistance or
gyroscopic effect of the rotor-head or the like for the
above-described period. In this way, when the rotational speed
decrease and a predetermined value of final braking torque is
applied by the braking means after the supply of the drive energy
to the drive motor is stopped, the impact between the teeth of the
first gear and the teeth of the second gear is reduced, whereby it
is possible to reduce the damage on the teeth of the first and
second gear and noise, and to make the apparatus small in size at a
low price.
[0034] The same braking means may be provided with both the impact
reduction function and the rotation restriction function of the
wind power generation unit at the time of the stoppage of the
motor, whereby the structure become simple and the manufacturing
cost becomes inexpensive compared to the case in which the two
braking means are provided according to their functions.
[0035] Additionally, the structure of the braking member is simple,
thus it can be provided at a low cost.
[0036] Further, it is possible to securely isolate a rotational
side frictional member and a fixed side frictional member with a
simple construction.
[0037] Further, during the rotation of the wind power generation
unit is stopped, when the wind power generation unit rotates due to
the excessive wind load caused by a gust or the like, this rotation
is transferred to the braking means, and a rotational side
frictional member rotates as it is while being frictionally
contacted with a fixed side frictional member, the braking means
may be heated by the frictional heat and damaged. However, it is
possible to prevent this accident by a construction in accordance
with an aspect of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1 is a view illustrating a first embodiment of the
invention.
[0039] FIG. 2 is a cross-sectional view taken along the line B-B of
FIG. 1.
[0040] FIG. 3 is a view illustrating a second embodiment of the
invention.
[0041] FIG. 4 is a graph illustrating a relationship among a
reduction gear ratio of an eccentric oscillating type speed
reduction mechanism, an efficiency of the eccentric oscillating
type speed reduction mechanism, a total efficiency of a speed
reducer for a yaw drive apparatus, and a total reduction gear
ratio.
[0042] FIG. 5 is a front cross-sectional view illustrating a third
embodiment of the invention.
[0043] FIG. 6 is a schematic circuit diagram of the third
embodiment of the invention.
[0044] FIG. 7 is a graph illustrating an operation timing of the
third embodiment of the invention, in which (a) illustrates a
relationship between time and a rotational speed of an output
shaft, (b) illustrates a relationship between time and a pressure
in a braking chamber, (c) illustrates a relationship between time
and A switching valve voltage, (d) illustrates a relationship
between time and B switching valve voltage, and (e) illustrates a
relationship between time and an on-off valve voltage.
[0045] FIG. 8 is a schematic circuit diagram illustrating a fourth
embodiment of the invention, which is similar to FIG. 6.
[0046] FIG. 9 is a graph illustrating an operation timing of the
fourth embodiment of the invention, in which (a) illustrates the
relationship between time and the rotational speed of the output
shaft, (b) illustrates the relationship between time and the
pressure in the braking chamber, (c) illustrates the relationship
between time and the A switching valve voltage, (d) illustrates the
relationship between time and the B switching valve voltage, (e)
illustrates the relationship between time and the on-off valve
voltage, and (f) illustrates a relationship between time and a
control valve voltage.
[0047] FIG. 10 is a front cross-sectional view illustrating a sixth
embodiment of the invention.
[0048] FIG. 11 is a schematic circuit diagram of the sixth
embodiment of the invention.
[0049] FIG. 12 is a graph illustrating an operation timing of the
sixth embodiment of the invention, in which (a) illustrates the
relationship between time and the rotational speed of the output
shaft, (b) illustrates a relationship between time and a breaking
voltage, (c) illustrates a relationship between time and a motor
voltage, (d) illustrates a relationship between time and a sensor
signal.
[0050] FIG. 13 is a schematic circuit diagram of a seventh
embodiment of the invention, which is similar to FIG. 11.
[0051] FIG. 14 is a graph illustrating an operation timing of the
seventh embodiment of the invention, in which (a) illustrates the
relationship between time and the rotational speed of the output
shaft, (b) illustrates the relationship between time and the
pressure in the breaking chamber, (c) illustrates a relationship
between time and the switching valve voltage, (d) illustrates the
relationship between time and the motor voltage, and (e)
illustrates the relationship between time and the sensor
signal.
BEST MODE FOR CARRYING OUT THE INVENTION
Example 1
[0052] Hereinafter, a first embodiment of the present invention
will be described with reference to FIGS. 1 and 2. FIG. 1 is a
longitudinal cross-sectional view seen from the A-A direction of
FIG. 2. FIG. 2 is a cross-sectional view taken along the line A-A
of FIG. 1.
[0053] A reference numeral 100 indicates a yaw drive apparatus of a
wind power generation apparatus. A reference numeral 200 indicates
a speed reducer used in the yaw drive apparatus 100. The speed
reducer 200 is constituted by a first stage speed reducing portion
10, a second stage speed reducing portion 20 connected to the first
speed reducing portion 10, and a third stage speed reducing portion
30.
[0054] The fist stage speed reducing portion 10 is constructed by a
planetary speed reduction mechanism comprising an input sun gear 3
as an input part, which is fixedly connected to an output shaft 2
of a motor 1, a plurality of (three) planetary gears 4 engaged with
the input sun gear 3 at the periphery of the input sun gear 3, an
internal gear member 6 having internal teeth 5 engaged with the
plurality of the planetary gears 4 at the periphery of the
plurality of the planetary gears 4, and a carrier 7 rotatably
supporting the plurality of planetary gears 4. The motor 1 is
attached to a supporting member 8 of the motor. The internal gear
member 6 is fixed to the supporting member 8 of the motor at the
inside thereof. A plurality of pins 10 rotatably supporting the
planetary gear 4 through a plurality of needles is fixed to the
carrier 7.
[0055] In the first stage speed reducing portion 10 constructed by
the planetary speed reduction mechanism, the reduction gear ratio
is selectively set to 1/3 to 1/20.
[0056] The second stage speed reducing portion 20 is constructed by
a spur gear type speed reduction mechanism constituted by an input
spur gear 21 connected to the carrier 7, and a plurality of (four)
spur gears 22 engaged with the input spur gear 21.
[0057] In the second stage speed reducing portion 20 constructed by
the spur gear type speed reduction mechanism, the reduction gear
ratio is set to 1/3. The second speed reducing portion 20 may be
selectively set to 1/2 to 1/5.
[0058] Therefore, a total reduction gear ratio of the first and
second speed reducing portions 10 and 20 is set to 1/27
(1/9.times.1/3). The total reduction gear ratio of the first and
second speed reducing portions 10 and 20 may be set to 1/6 to
1/100(1/3.times.1/2 to 1/20.times.1/5). However, in the speed
reducer of the invention used in the yaw drive apparatus, it is
preferable that the total reduction gear ratio of the first and
second speed reducing portions is set to 1/6 to 1/60.
[0059] The third stage speed reducing portion 30 is constructed by
an eccentric oscillating type speed reduction mechanism including a
fixed internal gear member 32 in which internal teeth 31 are formed
at the internal periphery thereof, a plurality of (two) external
gears 34, which are received in the internal gear member 32, which
have external teeth 33 engaged with the internal teeth 31 and
having number of teeth slightly less than that of the internal
teeth 31 at the external periphery thereof, and which are disposed
in parallel to each other in the axial direction, a plurality of
(four) crank shafts 35, which are rotatably inserted into the
plurality of external gears 34, and which are connected to the spur
gear 22 of the second stage speed reducer 20 and rotate to
eccentrically rotate the plurality of external gears 34, and a
carrier 37 as an output part, which rotatably supports both ends of
the crank shafts 35 through a pair of bearings 36. A pinion gear 39
having external teeth 38 engaged with a ring gear of a tower (not
shown) is provided at a leading end of the carrier 37 through a
spline connection. The pinion 39 may be formed at the leading end
of the carrier 37 through a machining. Each of the plurality of
spur gears 22 of the second stage speed reducing portion 20 is
attached to each end of the plurality of crank shafts 35. Each of
crank portions of the plurality of crank shafts 35 is inserted into
the inside of the plurality of external gears 34 through a needle
bearing 40. The carrier 37 is rotatably supported by the internal
gear member 32 through a pair of bearings 41. An oil-seal 42 is
inserted between the internal periphery of the leading end of the
internal gear member 32 and a supporting member 43 of the oil seal
42, which is attached to the periphery of the carrier 37. The one
end of the supporting member 8 of the motor is fixed to the end of
the internal gear member 32.
[0060] The reduction gear ratio of the third stage speed reducing
portion 30 constructed by the eccentric oscillating type speed
reduction mechanism is selectively set to 1/50 to 1/140.
[0061] The total reduction gear ratio of the speed reducer of the
present invention, which is constructed by three stage speed
reduction, is set to 1/1620(1/9.times.1/3.times.1/60). The total
reduction gear ratio of the speed reducer constructed by three
stage speed reduction may be set to 1/300 to
1/14000(1/3.times.1/2.times.1/50 to 1/20.times.1/5.times.1/140).
However, in the speed reducer according to the invention, used in
the yaw drive apparatus, it is preferable that the total reduction
gear ratio is set to 1/1000 to 1/3000.
Example 2
[0062] Next, a second embodiment of the invention will be described
with reference to a longitudinal cross-sectional view shown in FIG.
3.
[0063] In FIG. 3, a reference numeral 300 indicates a yaw drive
apparatus of a wind power generating apparatus. A reference numeral
400 indicates a speed reducer used in the yaw drive apparatus
300.
[0064] A first stage speed reducing portion 50 is constructed by a
spur gear type speed reduction mechanism constituted by a first
input spur gear 51 as an input part, which is fixedly connected to
the output shaft 61 of the motor 60, and a first spur gear 52
engaged with the first input spur gear 51.
[0065] The reduction gear ratio of the first speed reducing portion
50 constructed by the spur gear type speed reduction mechanism is
set to 1/6. The reduction gear ratio of the first stage speed
reducing portion 50 is selectively selected from 1/2 to 1/12. A
motor 60 is attached to the supporting member 62 of the motor.
[0066] A second stage speed reducing portion 70 is constructed by
the spur gear type speed reduction mechanism constituted by a
second input spur gear 53 connected to the first spur gear 52, and
a plurality of (four) second spur gears 54 engaged with the second
input spur gear 53. The second spur gear 53 is rotatably supported
by a supporting member 62 of the motor and a carrier 87 of the
eccentric oscillating type speed reduction mechanism to be
described later.
[0067] The reduction gear ratio of the second stage speed reducing
portion constructed by the spur gear type speed reduction mechanism
is set to 1/3. The reduction gear ratio of the second stage speed
reducing portion is selectively set to 1/2 to 1/5.
[0068] Therefore, a total reduction gear ratio of the first and
second speed reducing portions 50 and 70 is set to 1/18
(1/6.times.1/3). The total reduction gear ratio of the first and
second speed reducing portions 50 and 70 may be set to 1/4 to
1/60(1/2.times.1/2 to 1/12.times.1/5). However, in the speed
reducer of the invention used in the yaw drive apparatus, it is
preferable that the total reduction gear ratio of the first and
second speed reducing portions is set to 1/6 to 1/60.
[0069] The third stage speed reducing portion 80 is constructed by
an eccentric oscillating type speed reduction mechanism constituted
by a fixed internal gear member 82 in which internal teeth 31 are
formed at the internal periphery thereof, a plurality of (two)
external gears 84, which are received in the internal gear member
82, which have external teeth 83 engaged with the internal teeth 81
and having number of teeth slightly less than that of the internal
teeth 81 at the external periphery thereof, and which are disposed
in parallel to each other in the axial direction, a plurality of
(four) crank shafts 85, which are rotatably inserted into the
plurality of external gears 84, and which are connected to the
second spur gear 54 of the second stage speed reducer 70 and rotate
to eccentrically rotate the plurality of external gears 84, and a
carrier 87 as an output part, which rotatably supports both ends of
the crank shafts 85 through a pair of bearings 86. A pinion gear 89
having external teeth 88 engaged with a ring gear of a tower (not
shown) is provided at a leading end of the carrier 87 through
spline connection. Each of the plurality of the second spur gears
54 of the second stage speed reducing portion 70 is attached to
each end of the plurality of crank shafts 85. Each of crank
portions of the plurality of crank shafts 85 is inserted into the
inside of the plurality of external gears 84 through a needle
bearing 90. The carrier 87 is rotatably supported by the internal
gear member 82 through a pair of bearings 91.
[0070] An end of the supporting member 62 of the motor is fixed to
the end of the internal gear member 82. The reduction gear ratio of
he third stage speed reducing portion 80 constructed by the
eccentric oscillating type speed reduction mechanism is set to
1/60. The reduction gear ratio of the third stage speed reducing
portion 30 constructed by the eccentric oscillating type speed
reduction mechanism is selectively set to 1/50 to 1/140. The total
reduction gear ratio of the speed reducer of the invention, which
is constructed by three stage speed reduction, is set to
1/1080(1/6.times.1/3.times.1/60). The total reduction gear ratio of
the speed reducer constructed by three stage speed reduction may be
set to 1/200 to 1/8400(1/2.times.1/2.times.1/50 to
1/12.times.1/5.times.1/140). However, in the speed reducer
according to the invention, used in the yaw drive apparatus, it is
preferable that the total reduction gear ratio is set to 1/1000 to
1/3000.
[0071] Next, the operation of the present invention will be
described.
[0072] The rotation of the output shafts 2 and 61 of the motors 1
and 60 is reduced firstly at the first stage speed reducing
portions 10 and 50, secondly at the second speed reducing portions
20 and 70, and finally at the third speed reducing portions 30 and
80. Therefore, in the speed reducer constituted by the carriers 37
and 87, and three speed-reducing portions, for obtaining the total
reduction gear ratio of about 77% equal to that of the conventional
speed reducer constructed by connecting planetary speed reduction
mechanisms in five stages, it needs to set the reduction gear ratio
of the third speed reducing portion 30 constructed by the eccentric
oscillating type speed reduction mechanism according to the first
embodiment at about 85% (77%/95% at the first stage planetary speed
reduction mechanism/96% at the second spur gear type speed
reduction mechanism=about 85%).
[0073] FIG. 4 is a graph illustrating the relationship among the
reduction gear ratio of the eccentric oscillating type speed
reduction mechanism, the efficiency of the eccentric oscillating
type speed reduction mechanism, the total efficiency of the speed
reducer for the yaw drive apparatus, and the total reduction gear
ratio. In FIG. 4, the efficiency of the eccentric oscillating type
speed reduction mechanism is indicated by a line L1 and decreases
as the reduction gear ratio increases. The total efficiency of the
yaw drive apparatus is indicated by a line L2 and decreases as the
reduction gear ratio increases.
[0074] In order to maintain the total efficiency of the yaw drive
apparatus of 77%, it needs to set the reduction gear ratio of the
third stage speed reducing portion 30 constructed by the eccentric
oscillating type speed reduction mechanism at 1/140 or less at
which the total efficiency thereof is 85% or more. The ratio of
1/50 which is the minimum reduction gear ratio of the third stage
reducing portion 30 is determined from the total reduction gear
ratio of the first stage speed reducing portion 10 and the second
speed reducing portion 20 (60/3000=1/50).
[0075] In this way, even though the speed reducer is constituted by
the three stage speed reducing portions having a short axial
length, when the third speed reducing portion is constructed by the
eccentric oscillating type speed reduction mechanism and the
reduction gear ratio is set to 1/50 to 1/140, it is possible to
maintain the total efficiency of 77% required for the speed reducer
for the yaw drive apparatus of the wind power generation
apparatus.
[0076] When the total reduction gear ratio of the first and second
speed reducing portions is set to 1/6 to 1/60, and at the same
time, the reduction gear ratio of the eccentric oscillating type
speed reduction mechanism is set to 1/50 to 1/140, it is easy to
obtain the ratio of 1/1000 to 1/3000 which is the total reduction
gear ratio of the speed reducer required for the yaw drive
apparatus, even though the speed reducer is constituted by three
speed reducing portions.
[0077] Further, in the first and second embodiment, the
internal-geared gear bodies 32 and 82 of the eccentric oscillating
speed reduction mechanisms 30 and 80 are fixed, and the output
rotation is obtained from the carriers 37 and 87. However, in the
speed reducer of the present invention, the carriers 37 and 87 may
be fixed, and the output rotation may be obtained from the
internal-geared gear bodies 32 and 82. In this case, the pinions 39
and 89 are attached to the internal-geared gear bodies 32 and 82.
Further, the external teeth 38 and 88 engaged with the ring gear of
the tower may be formed at the external periphery of the
internal-geared gear bodies 32 and 82.
[0078] Further, in the first embodiment of the invention, the first
speed reducing portion is constructed by the planetary speed
reduction mechanism, and the second speed reducing portion is
constructed by the spur gear type speed reduction mechanism, and in
the second embodiment, the first and second speed reducing portions
are constructed by the spur gear type speed reduction mechanism.
However, both of the first and second speed reducing portions may
be constructed by the planetary speed reduction mechanism.
Example 3
[0079] Next, a third embodiment related to the yaw drive method and
apparatus using the above-described speed reducer will be described
with reference to the attached drawings.
[0080] In FIGS. 5 and 6, a reference numeral 111 indicates a tower
(column) of a wind power generation apparatus 112. A wind power
generation unit 113 is capable of yawing and supported at the upper
end of the tower 111 through a bearing 114, that is, it is
supported to rotate in a substantially horizontal plane. Here, the
wind power generation unit 113 has a well-known structure and is
constituted by a nacelle housing 115, a rotor head (not shown)
which is supported by the nacelle housing 115 and can rotate around
a substantially horizontal axis, a plurality of windmill blades
(not shown) of which a radial inner end is rotatably connected to
the rotor head, and a motor (not shown) which is fixedly received
in the nacelle housing 115 and generates a power using the rotation
transferred from the rotor head.
[0081] Here, an inner race of the bearing 114 is fixed to the
tower. However, a plurality of inner teeth 18 is formed at the
inner periphery of the inner race, so that the inner race forms a
ring-shaped inner gear 119 as a first gear attached to any one of
the tower 111 and the wind power generation unit 113 (in the third
embodiment, to the upper end of the tower 111). In this way, when
the inner race is commonly used to the inner gear 119, the entire
structure of the apparatus becomes simple, whereby the apparatus
can be reduced in size.
[0082] A reference numeral 120 indicates fluid motors as a
plurality of drive motors attached to the other side between the
tower 111 and the wind power generation unit 113 (in the third
embodiment, to the nacelle housing 115 of the wind power generation
unit 113) with the speed reducer 121 being interposed therebetween.
These fluid motors 120 are disposed with the same interval in the
peripheral direction. The fluid motor 120 (here, it is constituted
by the drive motor) is provided with drive energy, such that when
high-pressured fluid is supplied, an output shaft 122 rotates.
However, a rotational drive torque of the output shaft 122 is
reduced by a speed reducer 121 and is applied to a pinion 124 which
is an external gear as a second gear fixed to a rotational shaft
123 of the speed reducer 121 to rotate the pinions 124. The pinions
124 are engaged with the inner teeth 118 of the inner gear 119. As
a result, when the pinions 124 rotate as described above, the wind
power generation unit 113 yaws, supported at the tower through the
bearing 114.
[0083] A reference numeral 125 indicates a fluid pump which is
rotated by a motor 126 and discharges the fluid inhaled from a tank
127 into a supply passage 128 as highly-pressured fluid. A check
valve 129 is interposed in the supply passage 128. A plurality of
(here, the same number as that of the fluid motor 120) solenoid
type switching valves 131 controlled by a controller 130
constituted by a CPU or the like is connected to the distal end of
the check valve 129. Further, the switching valves 131 and the tank
127 are connected to each other through a discharge passage 132.
Reference numerals 133 and 134 indicate a pair of supply/discharge
passages which connect between the paired fluid motor 120 and the
switching valve 131. The supply/discharge passages 133 and 134 are
switched into a flow position (a parallel-flow position or a
cross-flow position), so that the one side becomes a high pressure
side and the other side becomes a low pressure side, whereby the
fluid motor 120 positively rotates or inversely rotates.
[0084] Since the anemoscope 137 and a potentiometer 138 are
connected to the controller 130, a wind direction signal from the
anemoscope 137 which indicates the present wind direction is input
to the controller 130. However, at this time, when the present wind
direction and the rotational direction of the wind power generation
unit 113 are different, the controller 130 switches the switching
valve 131 to rotate positively or inversely the fluid motor 120,
and yaws the wind power generation unit 113 by following the wind
direction such that the wind power generation unit 113 receives the
wind from the front side and generates with high efficiency.
[0085] A reference numeral 141 indicates a relief passage
connecting the supply passage 128 and the tank 127. A relief valve
142 for relieving pressure higher than the common line fluid
pressure circuit is interposed in the relief passage 141. The
relief valve 142 protects the fluid circuit from an abnormal high
pressure. A reference numeral 143 indicates a solenoid type on-off
valve connected to a pilot passage of the relief valve 142. The
on-off operation of the on-off valve 143 is controlled by the
controller 130. A reference numeral 144 indicates a reduction
passage connecting the on-off valve 143 and the tank 27. A low
pressure relief valve 145, of which relief pressure is set to a
pressure lower than that of the highly-pressured fluid (a common
line pressure) which is supplied to the fluid motor 120 in common
yawing of the wind power generation unit 113, is interposed in the
reduction passage 144.
[0086] When the on-off valve 143 is switched into on-state
(open-state) by the controller 130, the low pressure relief valve
145 relieves the fluid to the tank 127 and reduces the pressure of
the highly-pressured fluid supplied to the fluid motor 120 into a
pressure lower than the common pressure. The above-described on-off
valve 143, the reduction passage 144, and the relief valve 145
construct a reduction means 146 as a whole which makes the fluid
pressure supplied to the fluid motor 120 lower than that of the
highly-pressured fluid supplied to the fluid motor 120 in the
common yawing. Further, a proportional pressure control valve
capable of controlling the pressure of the passing fluid
proportionally to the input signal value from the controller 130
may be used as the reduction means 146, instead of the protective
relief valve 142. In this case, the above-described on-off valve
143, the reduction passage 144, and the low pressure relief valve
145 are unnecessary. The proportional pressure control valve
performs both the relief at the abnormal high pressure and the
relief at the pressure lower than that of the line pressure.
[0087] A reference numeral 151 indicates a negative brake which
uses a friction plate as a braking means capable of applying a
predetermined value of braking torque to the output shaft 122 of
the fluid motor 120. The negative brake 151 has a fixing casing 152
and a piston 153 is received in the fixing casing 152. Further, at
least one of a rotational friction plate 156 disposed between the
piston 153 and a stepped plane 154 of the fixing casing 152 and
spline-connected to the outside of the output shaft 122 of the
fluid motor 120, and at least one of a fixed friction plate 157
which is capable of being approached to or spaced from the
rotational friction plate 155 and which is spline-connected to the
inner wall of the fixing casing 152 are received into the fixing
casing 152.
[0088] A reference numeral 158 indicates a spring capable of
applying a biasing force to the rotational and fixed friction
plates 156 and 157 through the piston 153. The spring 158 presses
tightly the rotational and fixed friction plates 156 and 157
against the stepped plane to frictionally connect the rotational
and fixed friction plate 156 and 157 to each other. The
above-described fixing casing 152, the piston 153, the rotational
and fixed friction plates 156 and 157, and the spring 158 construct
the above-described negative brake 151 as a whole.
[0089] A reference numeral 159 indicates a selection passage
connecting the supply/discharge passages 133 and 134 to each other.
A selection valve 160, which selects and takes out the
highly-pressured fluid from the highly-pressured supply passage 133
or 134, is interposed in the selection passage 159. The
highly-pressured fluid taken out by the selection valve 160 is
induced into the braking chamber through the selection valve 160
and a brake passage 161 in the above-described braking casing 152.
At this time, the piston 153 moves away from the rotational and
fixed friction plates 156 and 157 against the spring 158 by the
highly-pressured fluid, whereby the rotational and fixed friction
plates 156 and 157 are spaced from each other.
[0090] Here, the braking chamber of the fixing casing 152 and the
tank 127 are connected to each other by a discharge passage (not
shown), and the switching valve 131 is interposed in the discharge
passage. When the switching valve 131 is switched into the flow
position, the discharge passage is closed by the switching valve
131. As a result, as described above, the highly-pressured fluid
taken out by the selection valve 160 is supplied to the braking
chamber, but when the switching valve is switched into neutral
position, the discharge passage communicates with the braking
chamber of the fixing casing 152 and discharges the fluid from the
braking chamber into the tank 127 and terminates the application of
the fluid power toward the piston 153.
[0091] In this way, from the time that the switching valve 131 is
switched into the neutral position and the supply of the
highly-pressured fluid toward the fluid motor 120 is stopped, the
fluid is discharged from the braking chamber of the fixing casing
152. As a result, the negative brake 151 brings the rotational and
fixed friction plates 156 and 157 to contact each other by the
biasing force by the spring 158, and applies the predetermined
value of the braking torque to the fluid motor 120. On the other
hand, from the time that the switching valve 131 is switched into
the flow position and the supply of the highly-pressured fluid
begins to start, the highly-pressured fluid taken from the
highly-pressured side supply/discharge passages 133 and 134 is
supplied into the braking chamber of the fixing casing 152, and
piston 153 is moves away from the rotational and fixed friction
plates 156 and 157 and the application of the braking torque toward
the fluid motor 120 is terminated.
[0092] Here, the reduction means 146 reduces the fluid pressure
with two timings by the control of the controller 130. The one
reduction of the fluid pressure, however, begins to start from when
the supply of the highly-pressured fluid toward the fluid motor 120
begins to start, and at the same time, the reduction of the fluid
pressure is terminated after a predetermined time is passed from
when the supply of the highly-pressured fluid toward the fluid
motor 120 begins to start. The other reduction of the pressure
begins to start from just before the supply of the highly-pressured
fluid is stopped and is terminated when the supply of the
highly-pressured fluid toward the fluid motor 120 is stopped.
Further, the reduction in the fluid pressure by the reduction means
146 must be performed during the above-describe period, but the
reduction in the fluid pressure is not interrupted. For example,
the fluid pressure can be reduced from a point of time before the
supply of the highly-pressured toward the fluid motor 120 starts to
begin, or can be reduced after the supply of the highly-pressured
fluid toward the fluid motor 120 is stopped.
[0093] In this way, since the pressure of the highly-pressured
fluid supplied into the fluid motor 120 is lowered than that of the
fluid from when the supply of the highly-pressured begins to start
to the time of the common yawing, the rotational drive torque,
which is applied from the fluid motor 120 when the rotation with
respect to the pinion is started, become small corresponding to the
energy of the fluid of which the pressure is reduced. As a result,
an impact between the teeth of the pinion 124 and the internal
teeth 118 of the internal gear 119 when the pinion 124 begins to
rotate is reduced, whereby it is possible to reduce the damage on
the teeth of the pinion 124 and internal gear 119 and noise, and to
make the apparatus small in size at a low price. After a short
predetermined time passes from this state, the rotational speed of
the output shaft 122 of the fluid motor 120 increases to some
degree. However, since the reduction of the fluid pressure by the
reduction means 146 is terminated at this point of time, from this
point of time, the fluid motor is supplied with the
highly-pressured fluid having the line pressure in common yawing
and the yawing of the wind power generation unit 113 is
performed.
[0094] Further, as described above, for a predetermined period
between the time just before the supply of the highly-pressured
fluid with respect to the fluid motor 120 is stopped and the supply
of the highly-pressured fluid is stopped, when the pressure of the
highly-pressured fluid supplied to the fluid motor 120 at this
period is lowered than the pressure in common yawing, and the
rotational power applied from the fluid motor 120 to the wind power
generation unit 113 is made small, the rotational speed of the wind
power generation unit 113 decreases gradually due to the frictional
effect or gyroscopic effect of the rotor-head or the like. When the
rotational speed decrease in this way, and a predetermined value of
braking torque is applied from the negative brake 151 to the fluid
motor 120 when the supply of the drive energy toward the fluid
motor 120 is stopped, the impact between the teeth of the pinion
124 and the internal teeth 118 of the internal gear 119 decreases,
whereby it is possible to reduce the damage on the teeth of the
pinion 124 and internal gear 119 and noise, and to make the
apparatus small in size at a low price.
[0095] Here, when the wind power generation unit 113 is at a state
in which the rotation thereof is stopped, and at the same time, the
braking torque is applied to the fluid motor 120 by the negative
brake 151, the wind power generation unit 113 may rotate against
the braking by the negative brake 151 due to the excessive wind
load applied to the wind power generation unit 113 caused by a gust
or the like. In this case, the rotation of the wind power
generation unit 113 is transferred to the fluid motor 120 and the
negative brake 151 through the internal gear 119, the pinion 124,
and the speed reducer 121, and the fluid motor 120 is rotated,
whereby the pump operation of the fluid motor 120 is performed and
at the same time the rotational and fixed friction plates 156 and
157 rotate with them being frictional contacted to each other. In
this case, when the pressure in the supply/discharge passages 133
and 134 increases to an abnormal high pressure, the negative brake
151 may be heated and damaged due to a frictional heat.
[0096] Therefore, in the third embodiment of the present invention,
the pair of supply/discharge passages 133 and 134 is connected to
each other by a connection passage 164 and at the same time, a
variable throttle 165 is interposed in the connection passage 164.
In this way, the pump operation of the fluid motor 120 is
performed, such that the fluid discharged to the supply/discharge
passage 133 and 134 flow to the supply/discharge passages 133 and
134 while being squeezed by the throttle 165, whereby it is
possible to prevent the pressure inside the supply/discharge
passages 133 and 134 from being raised to the abnormal high
pressure and to control the rotational speed of the fluid motor 120
by restricting the amount of the fluid passing through the throttle
165 within a predetermined amount.
[0097] Next, the operation of the third embodiment will be
described.
[0098] Assuming that the wind power generation unit 113 receives
the wind from the front side, such that the switching valve 131 is
converted into the neutral position, whereby the supply of the
highly-pressured fluid toward the fluid motor 120 is stopped and
the yawing of the wind power generation unit 113 is stopped. At
this time, since the fluid is discharged from the braking chamber
of the fixing casing 152 as shown in FIG. 7(b), the negative brake
151 brings the rotational and fixed friction plates 156 and 157 to
contact frictionally to each other by a biasing force of the spring
158, and applies a predetermined value of braking torque to the
fluid motor 120.
[0099] Next, when the wind direction is changed, the anemoscope 137
detects the wind direction and outputs the wind direction signal to
the controller 130. As a result, as shown in FIGS. 7(c) and 7(d),
the controller 130 applies a switching valve voltage to one side
coil of the switching valves 131A and 131B at time T1, and switches
the switching valves 131A and 131B into the flow position, for
example, the parallel-flow position. In this way, the
highly-pressured fluid discharged from the fluid pump 125 is
supplied to the fluid motor 120 through the supply passage 128 and
the supply/discharge passage 133 to rotate the fluid motor 120, and
at the same time, the fluid from the fluid motor 120 is discharged
into the tank 127 through the supply/discharge passage 134 and the
discharge passage 132.
[0100] In this way, when the highly-pressured-fluid is supplied to
the supply/discharge passage 133, the selection valve 160
selectively takes out the highly-pressured fluid from the supply
and discharge valve 133, and supplies it to the braking chamber in
the fixing casing 152 through the brake passage 161, raises the
pressure inside the braking chamber, as shown in FIG. 7(b). As a
result, the piston 153 receives the fluid pressure and moves away
from the rotational and fixed friction plates 156 and 157 against
the spring 158, and then terminates the application of the braking
torque with respect to the fluid motor 120 from the time T1.
[0101] Further, at the time T1, on-off valve voltage is applied to
the on-off valve 143 by the controller 130 as shown in FIG. 7(e),
and the on-off valve 143 is switched into on-state, such that the
relief valve 145 relieves the fluid into a low pressure and reduces
the pressure of the fluid supplied into the fluid motor 120 to a
pressure lower than a common line pressure. In this way, the
pressure of the highly-pressured fluid supplied to the fluid motor
120 is lowered by the reduction means 146 to a pressure lower than
the pressure (line pressure) of the fluid in the common yawing,
from the point of time T1 that the supply of the highly-pressured
fluid begins to start. Therefore, the rotational drive torque
applied to the pinion 124 from the fluid motor 120 at the time of
the start-up of the rotation become small corresponding to the
energy of the fluid of which the pressure is reduced. As a result,
an impact between the teeth of the pinion 124 and the internal
teeth 118 of the internal gear 119 when the pinion 124 begins to
rotate is reduced.
[0102] As described above, when the lowly-pressured fluid is
supplied to the fluid motor 120, the rotational speed of the output
shaft 122 of the fluid motor 120 is gradually raised as shown in
FIG. 7(a), but after a predetermined short time from the time T1,
at which the switching valve 131 is switched into the flow
position, and reaches time T2, the rotational speed of the output
shaft 122 is raised to some degree. At this time, as shown in FIG.
7(e), since the on-off valve 143 is switched into off-state (closed
state) by the controller 130, the fluid is not relieved from the
low pressure relief valve 145, and the pressure of the fluid
supplied to the fluid motor 120 is returned to the pressure (line
pressure) of the highly-pressured fluid supplied to the fluid motor
120 in the common yawing. As a result, the output shaft 122 of the
fluid motor 120 is rapidly accelerated, such that the rotational
speed thereof is to the normal rotational speed, and the wind power
generation unit 113 rotates in the common yaw rotational speed to
receive the wind from the front side.
[0103] The wind power generation unit 113 yaws by the point of time
just before it receives the wind from the front side. At the time
T3, as shown in FIG. 7(e), the on-off valve voltage is applied to
the on-off valve 143 from the controller 130, such that the on-off
valve 143 is switched into on-state and the low pressure relief
valve 145 is relieved. In this way, the pressure of the fluid
supplied to the fluid motor 120 is lowered, and the rotational
drive torque of the fluid motor 120 becomes to a small value. Then,
after the predetermined time from the time T3, when it reaches the
point of time T4 at which the supply of the highly-pressured fluid
is stopped, as shown in FIGS. 7(b) and 7(c), the application of the
switching valve voltage from the controller 130 with respect to the
switching valves 131A and 131B is terminated, and the switching
valves is switched into the neutral position. In this way, the
supply of the highly-pressured fluid with respect to the fluid
motor 120 is stopped.
[0104] As described above, for a predetermined short period between
the time just before the time T4 that the supply of the
highly-pressured fluid with respect to the fluid motor 120 is
stopped and the time T4, when the pressure of the fluid supplied to
the fluid motor 120 is lowered than the pressure (line pressure) of
the fluid supplied to the fluid motor 120 in common yawing, and the
rotational power applied from the fluid motor 120 to the wind power
generation unit 113 for this period is made small, the rotational
speed of the wind power generation unit 113 decreases gradually due
to the frictional effect or gyroscopic effect of the rotor-head or
the like.
[0105] Further, as described above, when the switching valve 131 is
switched into the neutral position at the time T4, the fluid is
discharged from the braking chamber of the fixing casing 152 to the
tank 127. At this time, the rotational and fixed friction plates
156 and 157 frictionally contact to each other due to the biasing
force of the spring 158 and the negative brake 151 applies a
predetermined value of braking torque to the fluid motor 120. When
the rotational speed of the wind power generation unit 113 decrease
in this way, and a predetermined value of braking torque is applied
from the negative brake 151 to the fluid motor 120 when the supply
of the drive energy toward the fluid motor 120, the impact between
the teeth of the pinion 124 and the internal teeth 118 of the
internal gear 119 decreases, whereby it is possible to reduce the
damage on the teeth of the pinion 124 and internal gear 119 and
noise, and to make the apparatus small in size at a low price.
[0106] As described above, when the braking torque is applied to
the fluid motor 120 from the negative brake 151, the rotational
speed of the output shaft 122 of the fluid motor 120 decreases
rapidly. Here, the on-off valve 143 may switch the switching valve
131 into the neutral position and at the same time into the
off-state at time T4. However, in the third embodiment, it
maintains for a predetermined time after the time T4. Then, it
reaches time T4, as shown in FIG. 7(a), the output shaft 122 of the
fluid motor 120 is stopped, and the yawing of the wind power
generation unit 113 is also stopped. At this time, the wind power
generation unit 113 receives the wind from the front side, whereby
the efficiency of the power generation increases.
[0107] Further, it reaches time T5, as shown in FIG. 7(d), the
switching valve voltage is applied from the controller to the other
side coil of the switching valve 131 (here, the switching valve
131B), and the switching valve 131B is switched into the cross-flow
position. As a result, the pressured fluid is supplied to the
supply/discharge passage 134 through the switching valve 131B.
However, the fluid pressure at this time is determined to be low by
the low pressure relief valve 145, since the on-off valve 143 keeps
the on-state from the time T3.
[0108] As described above, when the lowly-pressured fluid is
supplied to the supply/discharge passage 134, the negative brake
151 releases the fluid motor 120 from the braking, such that the
fluid motor 120 rotates the pinion 124 to the direction opposite to
the above-described direction. However, since the value of the
rotational drive torque at this time is small, the pinion 124
engaged with the internal teeth 118 of the internal gear 119 and
the backlash between them is removed. In this way, it is possible
to reduce more effectively the impact between the teeth of the
pinion 124 and the internal teeth 118 of the internal gear 119 at
the time of next start-up of the yawing of the wind power
generation unit 113.
[0109] Here, the switching valve voltage applied to some switching
valves 131 may be applied to one side coil contrary to the above
description. In this case, the pinion 124 rotates in the direction
same as that of the yawing. Further, when the switching valve
voltage is applied to any one side coil of some switching valves
131, the switching valve voltage may not be applied to the remained
switching valves 131 in many cases. However, the switching valve
voltage may be applied to the other side coil of the remained
switching valves 131. When it reaches time T6, as shown in FIGS.
7(d) and 7(e), the application to with respect to the switching
valve 131B is stopped, such that the switching valve 131B is
returned to the neutral position and at the same time, the
application of the on-off valve voltage with respect to the on-off
valve 143 is terminated, whereby the on-off valve 143 is switched
into off-stage. As a result, the rotation of the output shaft 122
of the fluid motor 120 is stopped, and the rotation of the wind
power generation unit 113 is stopped until the wind direction is
varied next time, whereby it becomes into a standby state.
[0110] During the rotation of the wind power generation unit 113 is
stopped, the wind power generation unit 113 may rotate against the
braking by the negative brake 151 due to the excessive wind load
applied to the wind power generation unit 113 caused by a gust or
the like. At this time, the fluid motor 120 performs a pump
operation, such that it sucks the fluid from one of the supply and
discharge valves 133 and 134 and at the same time, it discharges
the fluid to the other of the supply and discharge valves 133 and
134. At this time, since the switching valve 131 was switched into
the neutral position, the pressure inside the supply/discharge
passages 133 and 134 in the discharge side increases, whereby the
pressure inside the braking chamber of the fixing casing 152
increases rapidly as shown in FIG. 7(b) Therefore, the braking of
the negative brake 151 with respect to the fluid motor 120 is
released.
[0111] Further, at this time, the fluid discharged to the
supply/discharge passages 133 and 134 in the discharge side flows
into the supply/discharge passages 133 and 134 in the suction side
while being squeezed by the throttle 165, whereby it is possible to
prevent the pressure inside the supply/discharge passages 133 and
134 from being raised to the abnormal high pressure and to prevent
the output shaft 122 of the fluid motor 120 and the wind power
generation unit 113 from being rotated with high speed by
restricting the amount of the fluid passing the throttle 165 within
a predetermined amount to control the rotational speed of the fluid
motor 120. Further, since the pressure inside the supply/discharge
passages 133 and 134 in the discharge side serves as a back
pressure, it is possible to provide the braking to the fluid motor
120. Then, when it reaches time T8 and the rotation of the wind
power generation unit 113 is stopped, the pressure of the
supply/discharge passages 133 and 134 decreases, such that the
pressure inside the control chamber of the fixing casing 152 is
also reduced as shown in FIG. 7(b), and the negative brake 151
provides again the fluid motor 120 with the braking power.
Example 4
[0112] Next, a fourth embodiment of the yaw drive method and
apparatus by using the speed reducer will be described with
reference to FIG. 8. Here, since the structure of the fourth
embodiment is substantially same as that of the third embodiment in
many portions, the same portions are denoted by the same reference
numerals in the drawing and descriptions for them will be omitted,
and only portions different from the third embodiment will be
described. In FIG. 8, a reference numeral 170 indicates a counter
balance valve which is interposed in the supply/discharge passages
133 and 134 and has a check valve 171. When the wind power
generation unit 113 rotates by the rotation of the fluid motor 120,
if a large wind load operates in the same direction as the
rotational direction of the wind power generation unit 113, the
fluid motor 120 receives the wind load and performs the pump
operation. At this time the counter balance valve 170 receives the
pressure of the supply/discharge passages 133 and 134 in the
discharge side and is switched into a state close to the off-state,
thereby preventing the fluid motor 120 from being rapidly
rotated.
[0113] Further, in the fourth embodiment, a control valve 173 which
is switched by the control valve voltage output from the controller
130 on the basis of a wind velocity signal from an anemometer, a
fluid passage 176 which connects the control valve 173 and the
supply passage 128 with an accumulator 175 being interposed on the
way, a supply/discharge passage 177 connecting the control valve
173 and the control chamber of the negative brake 151, and a
discharge passage 178 connecting the control valve 173 and the tank
127 are provided instead of the selection passage 159, the
selection valve 160, and the brake passage 161.
[0114] In this way, the anemometer measuring the wind velocity is
further provided. During the rotation of the wind power generation
unit 113 is stopped, when the wind velocity measured by the
anemometer 172 is higher than a predetermined value, the output of
the control valve voltage is stopped, such that the control valve
173 is switched into the supply position. When the highly-pressured
fluid is supplied to the control chamber of the negative brake 151
from the supply passage 128, the fluid motor 120 is released from
the braking caused by the negative brake 151. In this way, it is
possible to prevent easily and securely a bad effect on the
apparatus which is caused by a fact that the fluid motor 120
rotates while receiving the braking from the negative brake 151,
when the excessive wind load caused by a gust or the like acts on
the wind power generation unit 113 and the fluid motor 120 performs
the pump operation. Further, since the control valve voltage is not
applied at the time of a stoppage of electric current, the control
valve 170 is switched into the supply position and induces the
highly-pressured fluid into the negative brake 151 from the
accumulator 175, thereby releasing the fluid motor 120 from the
braking caused by the negative brake 151.
[0115] Further, in the fourth embodiment, instead of the throttle
165, there is provided with a relief valve 180 interposed in the
connection passage 164. The relief valve 180 is switched into
on-state when the pressure in any one of the supply/discharge
passages 133 and 134 becomes to a predetermined pressure or more in
which the predetermined pressure is higher than a line pressure and
is lower than a relief pressure of the relief valve 142. In this
way, during the rotation of the wind power generation unit 113 is
stopped, when an excessive wind load caused by a gust acts on the
wind power generation unit 113, the fluid motor 120 performs the
pump operation, and the pressurse in the supply/discharge passages
133 and 134 are raised to the predetermined value or more, the
relief valve 180 is switched into on-state and the highly-pressured
fluid in the discharge side flows toward the suction side, whereby
it is possible to restrict the pressure at the discharge side to a
predetermined pressure (a relief pressure). As a result, the relief
pressure acts on the fluid motor 120 as a back pressure, such that
the fluid braking force is applied thereto, and the rotation of the
fluid motor 120 is restricted and at the same time, the torque is
controlled. In this way, it is possible to omit a hydraulic
pressure brake constituted by a brake disk fixed to the upper end
of the tower and frictional fixing type brake shoe in which the
brake disk is interposed, which is necessary to fix the
conventional wind power generation unit.
[0116] In the fourth embodiment, during the rotation of the wind
power generation unit 113, the control valve voltage is
continuously applied with respect to the control valve 173. Next,
when it approaches to a time T1, as shown in FIG. 9(f), the
application of the control valve voltage with respect to the valve
173 from the controller 130 is stopped. As a result, the
highly-pressured fluid is supplied to the control chamber of the
negative brake 151 from the supply passage 128 through the fluid
passage 176 and the supply/discharge passage 177, and the fluid
motor 120 is released form the braking due to the negative brake
151 at the time T1. Then, since the application of the control
valve voltage begins to start at a time T4, the negative brake 151
applies the braking force with respect to the fluid motor 120 from
the time T4.
[0117] Further, when the wind velocity increases to a predetermined
valve or more during the wind power generation unit 113 is stopped,
the application of the control valve voltage to the control valve
173 from the controller 130 is stopped and the control valve 173 is
switched into the supply position. In this way, the
highly-pressured fluid is supplied to the control chamber of the
negative brake 151 from the supply passage 128, and the fluid motor
120 is released from the braking due to the negative brake 151,
thereby preventing the bad effect on the apparatus from being
generated. The application of the control valve voltage is
restarted at a time T8 at which the rotation of the wind power
generation unit 113 is stopped. Further, another construction and
operation are same as that of the third embodiment.
Example 5
[0118] Next, the fifth embodiment of the yaw drive method and
apparatus by using the speed reducer will be described. In the
fifth embodiment, the reduction means 146 is omitted, and the
stoppage of the supply of the highly-pressured fluid with respect
to the fluid motor 120 is performed by stopping the supply of the
switching valve voltage to the switching valve 131 at a different
timing, that is, a time T3 different from the third and fourth
embodiments. At a time T4 after a predetermined short time is
passed from the time T3, the application of the control valve
voltage to the control valve 173 from the controller 130 begins to
start to switch the control valve 173 into the discharge position,
thereby applying a predetermined value of the braking torque to the
fluid motor 120.
[0119] As a result, for a period between the time T3 at which the
supply of the highly-pressured fluid with respect to the fluid
motor 120 is stopped and a time after the passage of a
predetermined time, the rotational speed of the wind power
generation unit 113 gradually decreases due to the frictional
effect or gyroscopic effect of the rotor-head or the like. Since
the above-described braking torque is applied from the negative
brake 151 to the fluid motor 120 when the rotational speed
decreases in this way, the impact between the teeth of the pinion
124 and the internal teeth 118 of the internal gear 119 decreases,
whereby it is possible to reduce the damage on the teeth of the
pinion 124 and internal gear 119 and noise, and to make the
apparatus small in size at a low price.
[0120] Further, in the above-described embodiment, the first gear
(internal gear 119) is attached to the tower 111, and the fluid
motor 120 is attached to the wind power generation unit 113.
However, in the present invention, the first gear may be attached
to the wind power generation unit and the drive motor may be
attached to the tower. Further, in the above-described embodiment,
the fluid motor 120 is used as the drive motor, but in the present
invention, a motor may be used. In this case, the drive energy is
an electric power. For the control of the supplied power, a
thyristor or a tirac is preferably used. Further, in the
above-described embodiment, the ring-shaped internal gear 119 is
used as a first gear, and the pinion 124 which is an external gear
is used as a second gear, but the external gear may be used as the
first and second gears. Further, in the above-described embodiment,
the fluid motors (drive motors) 120 are disposed to be spaced at
equal distance in the peripheral direction. However, the drive
motors may be disposed to be spaced at different distance in the
peripheral direction.
Example 6
[0121] Next, a sixth embodiment of the yaw drive method and
apparatus using the above-described speed reducer will be described
with reference to the attached drawings.
[0122] In FIGS. 10 and 11, a reference numeral 211 indicates a
tower (column) of a wind power generation apparatus 212. A wind
power generation unit 213 is capable of yawing and supported at the
upper end of the tower 211 through a bearing 214, that is, it is
supported to rotate in a substantially horizontal plane. Here, the
wind power generation unit 213 has a well-known structure and is
constituted by a nacelle housing 215, a rotor head (not shown)
which is supported by the nacelle housing 215 and can rotate around
a substantially horizontal axis, a plurality of windmill blades
(not shown) of which a radial inner end is rotatably connected to
the rotor head, and an electric generator (not shown) which is
fixedly received in the nacelle housing 215 and generates a power
using the rotation transferred from the rotor head.
[0123] Here, an inner race of the bearing 214 is fixed at the tower
211. However, a plurality of inner teeth 218 is formed at the inner
periphery of the inner race. As a result, the inner race constructs
a ring-shaped inner gear 219 as a first gear attached to any one of
the tower 211 and the wind power generation unit 213 (in the sixth
embodiment, to the upper end of the tower 211). In this way, when
the inner race is commonly used to the inner gear 219, the entire
structure of the apparatus becomes simple, whereby the apparatus
can be reduced in size.
[0124] A reference numeral 220 indicates motors as a plurality of
drive motors attached to the other side between the tower 211 and
the wind power generation unit 213 (in the sixth embodiment, to the
nacelle housing 215 of the wind power generation unit 213) with the
speed reducer 221 being interposed therebetween. These fluid motors
120 are disposed with the same interval in the peripheral
direction. When the fluid motor 220 is provided with drive energy,
here, since the drive motor is the motor, when it is provided with
an electric power, an output shaft of the motor 220 rotates.
However, the rotational drive torque of the output shaft is reduced
by a speed reducer 221 and is applied to pinions 223 which are the
external gears as second gear fixed to the rotational shaft 222 of
the speed reducer 221 to rotate the pinions 224. The pinions 223
are engaged with the inner teeth 218 of the inner gear 219. As a
result, when the pinions 223 rotate as described above, the wind
power generation unit 213 yaws, supported at the tower through the
bearing 214.
[0125] A reference numeral 226 indicates a controller such as CPU.
The controller 226 is provided with a wind direction signal from an
anemoscope 227 and a potentiometer 228. Further, the controller 226
operates the motor 220 on the basis of the wind direction signal
indicating the present wind direction and yaws the wind power
generation unit 213 following the wind direction of the wind power
generation unit 213 such that the wind power generation unit 213
receives from the front side and generates an electricity with a
high efficiency.
[0126] A reference numeral 231 indicates the braking means which is
provided to the motor 220 and is capable of applying the braking
torque of a value lower than the maximum drive torque of the motor
220. As the braking means 231, an electromagnetic brake using a
well known frictional plate is used in the sixth embodiment. When
the braking means 231 is electrified by the control of the
controller 226, the braking means 231 applies the braking torque to
the output shaft of the motor 220. On the other hand, when the
electrification with respect to the braking means 231 is stopped by
the control of the controller 226, the braking means 231 releases
the output shaft of the motor 220 from the braking.
[0127] Here, the braking means 231 begins to start the application
of the braking torque with respect to the motor by the control of
the controller 226 from at least two points of time. The
application of a start-up braking torque (torque for reduction) is
performed from when the electrification begins to start, and the
application of a final braking torque (torque for stoppage) is
performed after a predetermined time from when the electrification
with respect to the motor 220 is stopped. Further, the application
of the start-up braking torque is terminated after a predetermined
short time from when the electrification begins to start. On the
other hand, the application of the final braking torque may be
terminated after the rotation of the wind power generation unit 213
is terminated, but it is preferable that the braking torque is
applied continuously during the time of the stoppage of the yawing
without being terminated at least until the electrification to the
motor 220 begins to start for preventing the wind power generation
unit 213 being rotated due to the wind load or the like.
[0128] In this way, when the start-up braking torque is applied to
the motor 220 by the braking means 231 for a predetermined short
time from when the electrification to the motor 220 begins to
start, the rotational drive torque obtained by subtracting the
start-up braking torque from the output drive torque of the motor
220 is applied to the pinion 223. Here, as described above, since
the start-up drive torque has a predetermined value lower than the
maximum drive torque of the motor 220, the pinion 223 can rotate
for yawing the wind power generation unit 213. However, since the
rotational drive torque at this time has a small value obtained
from the above-described subtraction, and the rotational speed of
the pinion 223 is reduced by the start-up braking torque, an impact
between the teeth of the pinion 2223 and the internal teeth 218 of
the internal gear 219 is reduced, whereby it is possible to reduce
the damage on the teeth of the pinion 223 and internal gear 219 or
noise, and to make the apparatus small in size at a low price.
After a short predetermined time from this state, the rotational
speed of the motor 220 increases to some degree. However, at this
point of time, the application of the braking torque is terminated
and the yawing of the wind power generation unit is performed.
[0129] Further, as described above, when the motor 220 is applied
with the final braking torque by the braking means 231, after a
predetermined time from when the electrification with respect to
the motor 220 is terminated, the rotational speed of the wind power
generation unit 213 is reduced due to the gyroscopic effect or the
frictional resistance for a period that a predetermined time has
passed from when the electrification with respect to the motor 220
is terminated. The final braking torque is applied to the motor 220
from the braking means 231 when the rotational speed is reduced in
this way, such that an impact between the teeth of the pinion 223
and the internal teeth 218 of the internal gear 219 is reduced,
whereby it is possible to reduce the damage on the teeth of the
pinion 223 and internal gear 219 or noise, and to make the
apparatus small in size at a low price.
[0130] Here, the start-up braking torque and the final braking
torque may be constant regardless of the passage of the time, and
may be gradually decreased or increased with the passage of the
time. Further, the start-up braking torque value and the final
braking torque value may be equal to each other, or may be
different from each other. In particular, the value of the final
braking torque may be larger than that of the maximum drive torque
of the motor 220.
[0131] Further, in the sixth embodiment, the application of the
final braking torque is not terminated after a predetermined time,
but it continues by the braking means 231 until the electrification
to the motor 220 begins to start (as described above, the
electrification for the start-up braking torque begins to start
from this point of time), whereby the yawing of the wind power
generation unit 213 when the stoppage of the motor 220 is
restricted. In this way, when the same braking means 231 is
provided with both the impact reduction function and the rotation
restriction function of the wind power generation unit 213 at the
time of the stoppage of the motor 220, the structure become simple
and the manufacturing cost becomes inexpensive compared to the case
in which the two braking means are provided according to their
functions.
[0132] Here, when the wind power generation unit 213 is at a state
in which the rotation is stopped and at the same time, the braking
means 231 applies the braking torque (final braking torque) to the
motor 220, the wind power generation unit 213 may rotate against
the braking by the braking means 231 due to the excessive wind load
applied to the wind power generation unit 213 caused by a gust or
the like. In this case, the rotation of the wind power generation
unit 213 is transferred to the braking means 231 through the
internal gear 219, the pinion 223, and the speed reducer 221, and
the output shaft of the motor 220, and the rotation is performed
with the frictional plate being frictional contacted to each other.
In this case, the braking means 231 may be heated and damaged due
to a frictional heat.
[0133] Therefore, in this embodiment, the braking means 231 is
provided with a detection sensor 233 for detecting the temperature
inside the braking means 231, such that the temperature inside the
braking means 231 is always detected and the detection signal is
output to the controller 226. As a result, when the temperature
inside the braking means 231 due to the frictional heat is raised
to a permitted limit or more, the controller 226 terminates the
application of the braking torque to the motor 220 of the braking
means 231 on the basis of the abnormal signal from the detection
sensor 233, thereby preventing previously the accident such as the
above-described damage.
[0134] A reference numeral 235 indicates a fluid pump which is
rotated by the motor 236 and discharges the fluid sucked from a
tank 237 to a supply passage 238 as a highly-pressured fluid. A
check valve 239 and an accumulator 240 are interposed in the supply
passage 238, and a solenoid type switching valve 241 controlled by
the controller 226 is connected to the distal end of the supply
passage. Further, the switching valve 241 and the tank 237 are
connected by a discharge passage 242. A reference numeral 243
indicates a plurality of brake mechanisms attached to a nacelle
housing of the wind power generation unit 213 and is disposed at
the same interval at the peripheral direction.
[0135] Each brake mechanism 243 is constituted by a fluid cylinder
245 connected to the switching valve 241 through the
supply/discharge passage 244 and a frictionally fixed type brake
shoe 246. A reference numeral 247 indicates a ring-shaped brake
disk fixed to the upper end of the tower 211. When the fluid
cylinder 245 is supplied with the highly-pressured fluid, the brake
disk 247 is inserted into the brake shoe 246 from both sides, such
that the braking power is applied to the wind power generation unit
213, thereby preventing the wind power generation unit 213 from
being yawed little by little in a meaningless manner. The
above-described fluid pump 235, the motor 236, the switching valve
241, the brake mechanism 243, and the brake disk 247 construct a
fluid brake 248 as a whole.
[0136] Next, the operation of the sixth embodiment will be
described.
[0137] Assuming that the wind power generation unit 213 receives
the wind from the front side, such that the electrification to the
motor 220 is stopped, and the yawing of the wind power generation
unit 213 is stopped. At this time, as shown in FIG. 12(b), the
controller 226 electrifies the braking means 231 with a
predetermined voltage, and applies the braking torque with respect
to the output shaft of the motor 220. On the other hand, in the
fluid brake 248, the switching valve 241 is switched into the
supply position by the controller, and the highly-pressured fluid
discharged from the fluid pump 235 is supplied to the fluid
cylinder 245, such that the brake disk is inserted into the brake
shoe 246 to provide the fluid braking power to the wind power
generation unit 213.
[0138] Next, when the wind direction is changed, the anemoscope 227
detects the wind direction and outputs the change to the controller
226. As a result, as shown in FIG. 12(c), the controller 226
initiates the electrification with a predetermined voltage to the
motor 220 at a time T1, and drives the motor 220 to rotate.
Further, it reach the time T1, the switching valve 241 is switched
into the discharge position by the controller 226, such that the
fluid is discharged into the tank 237 from the fluid cylinder 245,
whereby the wind power generation unit 213 is released from the
braking of the fluid brake 248. On the other hand, the braking
means 231 applies the start-up braking torque to the motor 220 from
when the electrification to the motor 220 begins to start. However,
as described above, since the braking means 231 continuously
applies the braking torque during the rotation of the motor 220 is
stopped, the electrification to the braking means 231 is actually
performed continuously around the point of time, and the
application of the braking torque to the motor 220 is performed
continuously. In this way, when the start-up braking torque is
applied to the motor from the braking means 231 after the
electrification to the motor 220 begins to start, the rotational
drive torque obtained by subtracting the start-up braking torque
from the output drive torque of the motor 220 is applied to the
pinion 223, whereby the impact between the internal teeth of the
internal gear 219 and the teeth of the pinion 223 is reduced.
[0139] In this way, when the electrification to the motor 220
begins to start, the rotational speed of the output shaft of the
motor 220 gradually increases as shown in FIG. 12(a). However, when
a short time passes from the point of time T1 at which the
electrification begins to start and it reaches the time T2, and the
rotational speed of the output shaft is raised to some degree, as
shown in FIG. 12(b), the electrification to the braking means 231
is stopped, and the braking means 231 releases the output shaft of
the motor 220 from the braking. As a result, the output shaft of
the motor 220 is rapidly accelerated, such that the rotational
speed is raised to a normal rotational speed, and the wind power
generation unit 213 rotates at a normal yawing speed to receive the
wind from the front side. Further, when the wind power generation
unit 213 yaws to the position just before it receives the wind from
the front side, the electrification to the motor 220 is stopped as
shown in FIG. 12(c). This point of time is T3.
[0140] When a predetermined short time passes from the point of
time T3 that the electrification is stopped, and it reaches the
time T4, as shown in FIG. 12(b), the electrification to the braking
means 231 begins to start, and the application of the final braking
torque to the output of the motor 220 begins to start. Here, since
a predetermined short time is passed between the stoppage of the
electrification to the motor 220 and the application of the final
braking torque by the braking means 231, the rotational speed of
the wind power generation unit 213 decreases due to the gyroscopic
effect or the frictional effect of the rotor-head or the like.
Further, since the final braking torque is applied to the motor 220
from the braking means 231 when the rotational speed decreases, the
impact between the teeth of the pinion and the internal teeth of
the internal bear 219.
[0141] As described above, when the final braking torque is applied
to the motor from the braking means 231, the rotational speed of
the output shaft of the motor decreases rapidly as shown in FIG.
12(a), and when it reaches a time T5, the rotation thereof is
stopped, such that the yawing of the wind power generation unit 213
is also stopped. At this time, the wind power generation unit 213
receives the wind from the front side, such that the efficiency of
the generation of the electricity increases mostly. Further, at
this time, the switching valve 241 is switched into the supply
position by the controller 226, such that the highly-pressured
fluid discharged from the fluid pump 235 is supplied to the fluid
cylinder 245. The brake disk 247 is interposed by the brake
mechanism 243, and the wind power generation unit 213 is provided
with the fluid braking power in addition to the braking power of
the braking means 231.
[0142] The wind power generation unit 213 does not rotate from this
state in which the wind direction changes next time. However, the
wind power generation unit 213 may rotate against the braking by
the braking means 231 and the fluid brake 248 due to the excessive
wind load applied to the wind power generation unit 213 caused by a
gust or the like. In this case, the rotation of the wind power
generation unit 213 is transferred to the output shaft of the motor
through the internal gear 219, the pinion 223, and the speed
reducer 221. As shown in FIG. 12(a), the output shaft of the motor
220 initiates a high-speed rotation by a rapid acceleration from a
time T6. At this time, since it rotates with the frictional plates
of the braking means 231 being frictionally contacted to each
other, the frictional heat generates, whereby the braking means 231
is heated.
[0143] When the temperature inside the braking means 231 is raised
to a permitted temperature or more at a time T7, the detection
sensor 233, which detects always the temperature inside the braking
means 231, outputs the abnormal signal to the controller 226, as
shown in FIG. 12(d). As a result, the controller 226 stops the
electrification to the braking means 231 to terminate the
application of the braking torque to the braking means 231, and
releases the motor 220 from the braking caused by the braking means
231, thereby preventing the braking means 231 from being
damaged.
[0144] Then, when it reaches a time T8 and the rotation of the wind
power generation unit 213 is stopped and at the same time, the
temperature inside the braking means 231 decreases to a permitted
temperature or less, as shown in FIG. 12(d), the abnormal signal is
not output from the detection signal 233, but the controller 226
electrifies the braking means 231 at this time, as shown in FIG.
12(a), and the motor 220 is applied with the braking torque by the
braking means 231.
Example 7
[0145] FIG. 13 is a view illustrating a seventh embodiment of the
present invention. Here, since the structure of the seventh
embodiment is substantially same as that of the sixth embodiment in
many portions, the same portions are denoted by the same reference
numerals in the drawing and descriptions for them will be omitted,
and only portions different from the sixth embodiment will be
described. In FIG. 13, a reference numeral 251 indicates a braking
means which is provided to the motor 220 and is capable of applying
the motor 220 with a predetermined value of braking torque smaller
than the maximum drive torque of the motor. Here, as the braking
means 251, a fluid type negative brake using a well known
frictional plate.
[0146] The braking means 251 has a fixing casing 252 in which a
piston is rotatably received. Further, at least one of a rotational
friction plate 256 disposed between a piston 253 and a stepped
plane 254 of the braking means 251 and spline-connected to the
outside of an output shaft 255 of the motor 220, as a rotational
side frictional member, and at least one of a fixed friction plate
257 which is capable of being approached to or spaced from the
rotational friction plate 256 and which is spline-connected to the
inner wall of the fixing casing 252, as a fixed side frictional
member, are received in the fixing casing 252.
[0147] A reference numeral 258 indicates a spring capable of
applying a biasing force to the rotational and fixed friction
plates 256 and 257 through the piston 253. The spring 258 presses
tightly the rotational and fixed friction plates 256 and 257
against the stepped plane 254 to frictionally connect the
rotational and fixed friction plate 256 and 257 to each other.
[0148] A reference numeral 259 indicates a fluid passage connected
to the fixing casing 252, and a throttle 260 is interposed in the
fluid passage. When the highly-pressured fluid is induced to the
braking chamber inside the fixing casing 252 through the fluid
passage 259, the piston 253 moves away from the rotational and
fixed frictional plate 256 and 257 against the spring 258, whereby
the rotational and fixed frictional plate 256 and 257 are separated
from each other. A reference numeral 261 indicates a switching
valve connected to the fluid passage 259. The other end of the
supply passage 262 of which one end is connected to the supply
passage 238 between the accumulator 240 and the switching valve
241, and the other end of the discharge passage 263 of which one
end is connected to the tank 237 are connected to the switching
valve 261. When the switching valve 261 is switched into the supply
position by the controller 226, the highly-pressured fluid from the
fluid pump 235 is supplied to the braking chamber of the fixing
casing 252. On the other hand, when the switching valve 261 is
switched into the discharge position, the fluid is discharged from
the braking chamber of the fixing casing 252.
[0149] The above-described fluid passage 259 and the throttle 260
construct an isolating mechanism 264 as a whole for isolating the
rotational and fixed frictional plates 256 and 2577 against the
spring 258. When the isolating mechanism 264 is constructed by the
fluid passage 259 and the throttle 260 as described above, it is
possible to isolates securely the rotational and fixed frictional
plate 256 and 257 with a simple construction. Further, the
above-described fixing casing 252, the piston 253, the rotational
and fixed frictional plate 256 and 257, and the isolating mechanism
264 construct the braking means 251 as a whole. In this way, when
the braking means 251 is constructed by the fixed casing 252, the
piston 253, the rotational and fixed frictional plate 256 and 257,
and the isolating mechanism 264, it is possible to make the braking
means 251 inexpensive with a simple construction.
[0150] In the seventh embodiment, as shown in FIG. 14(d), at a time
T1, the electrification with a predetermined voltage to the motor
220 begins to start. On the other hand, the application of the
valve switching voltage to the switching valve 261 begins to start
as shown in FIG. 14(c), and the switching valve 261 is switched
into the supply position. As a result, the highly-pressured fluid
from the fluid pump 235 is supplied to the control chamber inside
the fixing casing 252 through the supply passages 238 and 262, and
the fluid passage 259, and the pressure inside the control chamber
is raised as shown in FIG. 14(b). At this time, since the throttle
260 is interposed in the fluid passage 259, an amount of fluid by
unit time which is supplied to the control chamber of the fixing
casing 252 is restricted to a small amount.
[0151] In this way, the piston 253 moves against the spring 258 at
a low speed, and a predetermined time is required for the
rotational and fixed frictional plates 256 and 257 to be isolated
from each other. Therefore, the rotational and fixed frictional
plates 256 and 257 of the braking means 251 maintain the frictional
contact state (same as the state before the time T1) by the biasing
force of the spring 258 for a predetermined time from the time T1,
and apply the start-up braking torque same as that in the
description with respect to the motor 220. In this way, since the
start-up braking torque applied to the motor 220 from the braking
means 251 even after the electrification to the motor 220 begins to
start, the impact is reduced similar to the sixth embodiment.
[0152] Next, it reaches to a time T3, the electrification to the
motor 220 is stopped as shown in FIG. 14(d), and at the same time,
the application of the valve switching voltage to the switching
valve 261 is terminated as shown in FIG. 14(c), and the switching
valve 261 is switched into the discharge position. As a result, due
to the biasing force of the spring 258, the fluid is discharged
from the control chamber of the fixed casing 252 to the tank 237
through the supply passages 238 and 262, and the fluid passage 259,
and the pressure inside the control chamber decreases as shown in
FIG. 14(b). At this time, since the throttle is interposed in the
fluid passage 259, the amount of the fluid per unit time, which is
discharged from the control chamber of the fixing casing 252, is
restricted to a small amount.
[0153] In this way, the piston 253 moves at a low speed, and a
predetermined time is required for the rotational and fixed
frictional plates 256 and 257 to be frictionally contacted to each
other. In this way, since the final braking torque is applied for
the first time to the motor 220 from the braking means 251 after a
predetermined short time passes since the electrification to the
motor 220 has been stopped, the rotational speed of the wind power
generation unit 213 decreases, whereby the impact is reduced
similar to the sixth embodiment.
[0154] Further, during the rotation of the wind power generation
unit 113 is stopped, the excessive wind load caused by a gust or
the like may be applied to the wind power generation unit 213. Due
to this, the wind power generation unit 213 rotates and at the same
time the output shaft 255 of the motor 220 rotates at a high speed,
such that the rotational and fixed frictional plates 256 and 257 of
the braking means 251 may generate large amount of heat. In this
case, since the detection sensor 233 outputs an abnormal signal to
the controller 226 at a time T7 as shown in FIG. 14(e), the
controller applies the valve switching voltage to the switching
valve 261 as shown in FIG. 14(d), and it switches the switching
valve 261 into the supply position. As a result, the
highly-pressured fluid is supplied to the braking chamber of the
fixing casing 252 and the motor 220 is released from the braking
caused by the braking means 251. Then, when the temperature inside
the braking means 231, the braking torque is applied again to the
motor 220 by the braking means 251. Further, another construction
and operation is same as that of the sixth embodiment.
Example 8
[0155] Next, an eighth embodiment will be described. In the eighth
embodiment, when the yawing of the wind power generation is
stopped, the application of the above-described final braking
torque does not performed. Alternatively, for a predetermined
period from just before the point of time at the electrification
with respect to the motor 220 is stopped to the point of time at
which the electrification begins to start, the value of the
electric power electrified to the motor 220 is made smaller than
the electric power supplied to the motor 220 in the common yawing
by controlling the triac, the thyristor or the like by the
controller 226, whereby the rotational power applied to the motor
220 for the period is made small. In this way, the rotational speed
of the wind power generation unit 213 gradually decreases due to
the frictional effect or gyroscopic effect of the rotor-head or the
like. When the rotational speed decreases in this way, and a
predetermined value of final braking torque is applied to the motor
220 after the electrification to the motor is stopped, the impact
between the teeth of the pinion 223 and the internal teeth 218 of
the internal gear 219 decreases, whereby it is possible to reduce
the damage on the teeth of the pinion 223 and internal gear 219 and
noise, and to make the apparatus small in size at a low price.
[0156] In the above-described embodiment, the first gear (internal
gear 219) is attached to the tower 211, and the motor 220 is
attached to the wind power generation unit 213. However, in the
present invention, the first gear may be attached to the wind power
generation unit and the drive motor may be attached to the tower.
Further, in the above-described embodiment, the motor 220 is used
as the drive motor, but in the present invention, the fluid motor
may be used. In this case, the drive energy is a highly-pressure
fluid. Further, in the above-described embodiment, the start-up
braking torque and the final braking torque are applied by the same
braking means 231. However, in the present invention, the start-up
braking torque and the final braking torque may be applied by
different braking means, respectively.
[0157] Further, in the above-described embodiment, the ring-shaped
internal gear 219 is used as the first gear, and the pinion 223
which is an external gear is used as a second gear, but the
external gear may be used as the first and second gears. Further,
in the above-described embodiment, the motors (drive motors) 220
are disposed to be spaced at equal distance in the peripheral
direction. However, the drive motors may be disposed to be spaced
at different distance in the peripheral direction.
[0158] Here, when the fluid motor is used instead of the motor 220
in the eighth embodiment, in the connection passage connecting the
high pressure side supply/discharge passage connected to the fluid
motor and the tank, a proportional pressure control valve capable
of linearly controlling the pressure passing through the passage,
or on-off valve and a low pressure relief valve are preferably
interposed in this order. In this way, in case of the yawing of the
wind power generation unit, the pressure in the high pressure side
supply/discharge passage is maintained at a common high pressure by
setting the proportional pressure control valve at a high pressure
or switching the on-off valve into an off-state. On the other hand,
in case of the predetermined period from just before the supply of
the highly-pressured fluid to the fluid motor is stopped until the
supply is stopped, the proportional pressure control valve may be
set to a low pressure, or the on-off valve is switched into
on-state, such that the fluid is relieved form the low pressure
relief valve, and the pressure inside the high pressure side
supply/discharge passage may be decreased compared to the common
high pressure.
INDUSTRIAL APPLICABILITY
[0159] According to the present invention, it is possible to a
speed reducer and a yaw drive apparatus for a wind power generation
apparatus, in which the speed reducer has high efficiency and a
short axial length, and suitable for the yaw drive apparatus.
Further, it can be applied to a yaw drive apparatus which performs
a generation of electricity by rotating a windmill by using a wind,
and which is excellent in efficiency and is compact in size.
* * * * *