Planetary gear transmission systems or components – Planetary gearing or element
Reexamination Certificate
1999-06-17
2001-01-23
Estremsky, Sherry (Department: 3681)
Planetary gear transmission systems or components
Planetary gearing or element
C475S346000, C290S055000
Reexamination Certificate
active
06176804
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to planetary gear trains and, more particularly, to planetary gear trains for wind power stations.
BACKGROUND OF THE INVENTION
Transmission constructions are known in which the gear train of a wind power station comprises a driven shaft rotated by at least one blade of the wind power station and a planet gear frame connected with the shaft and which revolves along with the driven shaft. Planet gears of the gear train mesh operationally with a ring gear which is fixedly mounted on the outer end of the gear train. The planet gears also mesh operationally with a sun gear which is located in the center of the gear train and which is rotated by the planet gears. The sun gear further rotates an output shaft by means of intermediate gears or directly, the output shaft being connected to an electric generator of the wind power station for generating electricity.
In the prior art constructions such as that discussed above, the teeth on the planet gears are straight which results in several drawbacks. For example, with such constructions, the noise and vibration levels of the planetary gear train reach undesirable levels.
OBJECTS AND SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a planetary gear train which is free from the above-mentioned drawbacks. Specifically, it is an object of the present invention to provide a planetary gear train which has reduced noise and vibration levels resulting from a novel form of the teeth.
These and other objects of the present invention are achieved by the new and improved planetary gear train of the present invention for a wind power station which comprises planet gears having helical teeth such that the teeth run diagonally across the entire mantle face of the gearwheels. Preferably, similar helical teeth are also provided on a central sun gear rotated by the planet gears and on a fixed outermost ring gear.
In accordance with the invention, the sun gear is an oblong shaft which is a floating construction. Thus, the sun gear is permitted to move slightly in an axial direction. At the end of the sun gear shaft, on the frame of a coupling, a flange is provided which receives the axial forces which arise in operation as well as the axial movement of the shaft. The sun gear shaft is an oblong shaft which comprises a center bore through the length thereof, the teeth of the sun gear at one of its ends and a flange that receives the axial forces at the opposite end. The circumferential face of the flange includes one toothing of a gear coupling. A backup flange jointly operative with the flange of the sun gear is located on the frame of the gearbox. A sleeve shaft is coupled, preferably by screw means, to the backup flange and the sun gear shaft is arranged inside the sleeve shaft. The sun gear shaft is connected with the sleeve shaft by the intermediate of a gear coupling. The gear coupling is structured and arranged to permit axial movement between the shaft of the sun gear and the sleeve shaft. By means of the gear coupling, the rotation drive of the sun gear is transferred to the sleeve shaft and to a gearwheel connected with the sleeve shaft and further. The sleeve shaft is further connected with a gearwheel from which the rotation drive is transferred either directly or through one or more intermediate gearwheels to an output shaft and further to an electric generator. By means of sleeves connected with the end of the sun gear shaft, forces in the opposite direction, arising from so-called back strokes, are received. The sleeve, which is provided with a flange, is coupled to the sun gear shaft preferably by means of screws.
The sleeve shaft is placed in a fixed axial/radial position and is mounted on the frame of the gear train preferably by bearing means. The sleeve shaft is coupled to a gearwheel which transfers the drive either directly or through one or more intermediate gearwheels to one or more output shafts, from which the drive is transferred to the electric generator for generating electricity.
In accordance with the invention, a first toothing of the gear coupling is arranged at the end of the sun gear shaft. The first toothing of the sun gear shaft is coupled with the backup or second toothing of the sleeve shaft, i.e., with the second toothing of the gear coupling. The teeth in the gear coupling are straight and crowned in the longitudinal direction of the tooth only, in which case, a certain angular bending is permitted for the sun gear shaft. A relative movement is permitted between the end flange of the sun gear shaft and the backup flange provided on the frame of the gearbox. The end flange of the sun gear shaft and the backup flange revolve at the same speed. An axial movement is permitted between them so that the flanges can reach contact with each other. With such an arrangement, any axial forces arising from the helical toothings on the sun gear, on the planet gears and on the ring gear and an axial movement of the sun gear shaft can be received at the end of the sun gear shaft, whereby this axial movement is restricted.
By means of the helical toothing on the sun gear, a drive of a wind power station is obtained which is highly free from vibrations and free from noise.
REFERENCES:
patent: 3754484 (1973-08-01), Roberts
patent: 3793899 (1974-02-01), Bourbonnaud
patent: 3915026 (1975-10-01), Otto
patent: 4106366 (1978-08-01), Altenbokum et al.
patent: 4239977 (1980-12-01), Strutman
patent: 4331040 (1982-05-01), Swasey
patent: 4586400 (1986-05-01), Nygren
patent: 5140170 (1992-08-01), Henderson
patent: 5466198 (1995-11-01), McKibbin et al.
patent: 2558093 (1977-06-01), None
patent: 3034443 (1982-04-01), None
patent: 0635639 (1995-01-01), None
patent: 0719964A1 (1996-07-01), None
patent: 0719964B1 (1999-08-01), None
patent: 851921 (1985-11-01), None
patent: 1558033 (1979-12-01), None
patent: 9119916 (1991-12-01), None
Second International Symposium on Wind Energy Systems; Oct. 3-6, 1978; pp. C6-89-C6-106; BHRA Fluid Engineering, Cranfield, Bedford, England.
Kekki Juha
Ryymin Ari
Villgren Voitto
Estremsky Sherry
Steinberg & Raskin, P.C.
Valmet Voimansiirto Oy
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