Abstract:
A compact drive which has a high transmission ratio for driving generators by wind force and permits simple assembly and maintenance. The gearing is a slip-on gearing having a multi-stage epicyclic gearing arrangement and a spur-gear stage for the drive output to a generator. The force is introduced into the epicyclic gearing arrangement via a ring gear, which drives planet gears, on whose shafts fixed to the housing in each case further planet gears are arranged. The planet gears mesh with a sun gear, from which the drive output to the spur-gear stage is effected.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to gearing for driving generators by rotors of wind installations, which gearing is designed as slip-on gearing. 
     2. Background of the Invention 
     The invention is based on slip-on a gearing which is connected by a press fit to the rotor shaft of a wind installation, with which the wind force is directed into the gearing. In this known embodiment, the hub of the press fit is connected to a planet carrier or a part of the planet carrier and is guided in the gear housing by bearings. The planet gears of the revolving planet carrier roll on a ring gear fixed to the housing and at the same time mesh with a sun gear, by means of which the power is increased. From the sun-gear shaft of this first stage, the power is transmitted into the planet carrier of a second epicyclic stage. This revolving planet carrier guides the planet gears arranged on it in a further ring gear fixed to the housing, and the planet gears drive a sun gear. From there, the power is passed by the pinion shaft of single-stage spur gearing into a generator by means of the gearing. 
     These gearing arrangements are of complex construction, have large overall lengths and are expensive to assemble and maintain. 
     SUMMARY OF THE INVENTION 
     Against this background, the object of the invention is to present a more compact drive which has a high transmission ratio and permits simple assembly and maintenance. 
     This object is achieved according to the invention by introducing force into an epicyclic gearing arrangement via a ring gear, which drives at least one planet gear, on whose shaft, fixed to housing, is a planet gear. This planet gear meshes with a sun gear from which drive output to a spur-gear stage is effected. 
     A favorable direct flow of force occurs due to the advantageous bearing arrangement according to the invention. 
     The load-carrying capacities of the ring-gear teeth and those of the sun gear are optimally utilized due to the torque division according to the invention. 
     The invention permits simple assembly of the entire arrangement and monitoring of the easily accessible bearings of the planet gears. 
     The arrangement according to the invention of the sun-gear shaft also permits the extraction of the sun gear. 
     In gearing according to the invention, only small masses revolve around the central axis, as a result of which better efficiency and simple monitoring is made possible. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, wherein like reference numerals denote similar elements: 
     FIG. 1 shows a longitudinal section through a gearing arrangement according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention is now explained in more detail with reference to FIG.  1 . The rotor shaft  13  is shown as a truncated illustration and carries a wind wheel or wind vane or the like at its end which is not shown. This shaft end is fastened to the tower of the installation by a bearing. At its gearing-side end, the rotor shaft  13  is mounted in the housing  16  at an extension  23 , which lengthens the rotor shaft  13 . The extension  23  may be flange-mounted as a separate component, may be turned as a step on the rotor shaft  13 , or may also be built onto the shaft end as a complete construction unit consisting of the ring-gear carrier  12  and the extension  23 , in which case this construction unit itself may also be in one piece. The rotor shaft  13  is bored out for accommodating control devices for influencing the wind vane. The extension  23  therefore also has a passage, which is directed with a tube  5  through the flange housing  20  and permits the fitting of further control devices on that side of the housing  20  which is remote from the wind wheel. 
     The ring-gear carrier  12  is arranged on the driving end of the rotor shaft  13 , that is in the region close to the end but in front of the extension  23 . This connection to the rotor shaft  13  is made as a shrink fit by means of a shrink disc  14 . Further embodiments provide for a press fit or a form fit by a splined-shaft connection. However, other shaft/hub connections are also possible. The ring-gear carrier  12  accommodates the ring gear  18 , which drives the force from the rotor shaft  13  into one or more planet gears  17 . A further planet gear  19  which meshes with the sun gear  8  is in each case arranged in an axially offset manner on the shafts, rotatably mounted in the housing  16 , of the planet gears  17 . From the sun gear  8 , which is centered in a floating position between a plurality of planet gears, the force is directed via the bored-out sun-gear shaft  4  by a coupling  6 , preferably a toothed coupling, to a hub  24 , in the interior of which the sun-gear shaft  4  is accommodated. 
     Without additional outlay in terms of design, the epicyclic gearing stages  18 ,  17 ,  19 ,  8  can be made with helical tooth systems, in which case the axial forces of the planet gears  17 ,  19  are compensated and the advantages of helical tooth systems, such as smoother running properties or higher load-carrying capacity, can be utilized. 
     Drive fluctuations, which are due to irregular wind conditions or other effects, are alleviated or compensated for by an elastic axial fastening of the sun-gear shaft. 
     Furthermore, it is possible to obtain information about the current operating data of the installation, such as torque, power output, etc., by measuring the axial forces which occur. If these data are known, appropriately controlled intervention in the operating sequence may then be carried out, e.g. shutdown in the event of overload and the risk of destruction of the gearing. To this end, a sensor  25  is preferably attached to the hub  24 , which is mounted in an axially fixed position. The sensor  25  records the force with which the sun-gear shaft  4 , fastened to the hub  24  in an axially elastic manner, presses on the hub  24 . A suitable sensor  25  for this purpose is, for example, a load cell (based on piezoelectric, inductive or similar principles) or a displacement transducer which records the relative movements between the sun-gear shaft  4  and the hub  24  and indirectly, via the spring constant of the elastic connecting member, provides information about the force which occurs. 
     The hub  24  carries a spur gear  7 , which meshes with a pinion  2 , which is preferably milled directly onto the output shaft  3 . The drive power is directed into the generator from the output shaft  3 . 
     The gearing-side end of the rotor shaft  13  is mounted with a bearing  9  which is supported in the planet carrier  12 , which forms a unit with the housing  16 . The bearing  9  is virtually in alignment with the torque supports  10 , which absorb the reaction moment of the housing  16  and direct it into the tower of the installation. All the forces or moments which occur are therefore passed into the one-piece housing  16  by direct transmission of force and there are no complicated joints via which the force has to be directed. The tilting moment of the gearing is supported with respect to the rotor shaft  13  via a bearing  11 . In the embodiment shown, the bearing  11  is arranged inside the planet carrier; in further design variants, however, this bearing may be shifted to the passage opening for the ring-gear carrier  12  through the wall of the housing  16 . In these exemplary embodiments, the housing  16  is then indirectly supported on the rotor shaft  13  via the ring-gear carrier  12 . 
     The ring gear  18  may be connected to the ring-gear carrier  12  both with a combination of frictional and positive-locking elements and purely by positive locking. To this end, screwed connections are produced, which are reinforced with straight pins, or an axially secured toothed coupling is used. 
     The planet-gear shafts are mounted on both sides of the first planet gear  17  in the planet carrier, which forms an integral unit with the housing  16 . In each case a second planet gear  19  is attached to the free shaft end projecting into the flange housing  20 . 
     The flange housing  20  is flange-mounted on the housing  16  and encloses the second epicyclic gearing stage  19 ,  8  on its open side. On its closed side, the flange housing  20  accommodates the spur-gear stage  7 ,  2 . The hub  24  is mounted on both sides of the spur gear  7 , on the one hand in the outer wall of the flange housing  20 , and on the other hand in a bearing  22  which is introduced into the seated bearing cap  15 , which also carries the bearing  21 , directed towards the epicyclic stage  19 ,  8 , of the output shaft  3 . The output shaft  3  is supported in a further bearing in the outer wall of the flange housing  20 . Through the use of the bearing cap  15 , a horizontal division, which would entail a sealing problem, at the flange housing  20  can be dispensed with. 
     Depending on the embodiment, the slip-on gearing  1  can either be fitted to the rotor shaft  13  as a completely preassembled unit or can be assembled in stages. 
     For maintenance purposes, after a housing lid on the closed side of the flange housing  20  has been removed, the sun gear  8  together with the sun-gear shaft  4  can be removed from the gearing. 
     Furthermore, it is possible to monitor the function of the easily accessible bearings of the non-revolving planet-gear shafts, for example, via structure-borne-noise measurements. 
     The advantageous introduction of force via the ring gear  18  into the first epicyclic gearing stage  18 ,  17 , which does not need a sun gear, which limits the loading capacity, results in favorable preconditions for the design, so that the construction can be very compact. The loading limit, which is thus shifted outwards, and the consequently optimum utilization of the material characteristics can be further increased by case hardening the teeth of the ring gear. With the power transmission remaining the same and with the same transmission ratio, it is possible by means of this especially advantageous measure to design the tooth width to be narrower or to reduce the diameter of the ring gear  18 . As a result, the overall volume and the weight of the gearing can be further reduced or, with the same dimensions of the components, a greater power output can be transmitted with the same gearing. 
     To increase the limit of the loading capacity of the ring-gear teeth, other surface-hardening processes, such as, for example, induction hardening, flame hardening or combined processes such as carbonitriding or nitrocarburizing, may also be used. 
     Thus, while there have been shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.