| 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 -> Monitor Keywords |
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  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 reducerUSPTO Application #: 20060205554Title: 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. (end of abstract) Agent: Akin Gump Strauss Hauer & Feld L.L.P. - Philadelphia, PA, US Inventors: Osamu Nohara, Katsuhiko Yokoyama, Sadayuki Tanabe USPTO Applicaton #: 20060205554 - Class: 475179000 (USPTO) Related Patent Categories: Planetary Gear Transmission Systems Or Components, Planet Periphery Surrounds Axis Of Interacting Gear (e.g., Eccentrically Driven Transmisson), Circumferentially Spaced Connector Pins, Roller Bearing Surrounds Pin The Patent Description & Claims data below is from USPTO Patent Application 20060205554. Brief Patent Description - Full Patent Description - Patent Application Claims
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. Continue reading... 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