GB798273A - Improvements relating to planetary gearing - Google Patents

Abstract

798,273. Toothed gearing. GENERAL MOTORS CORPORATION. Oct. 31, 1956 [Nov. 4, 1955], No. 33224/56. Class 80 (1). [Also in Group XXXIII] In planetary reduction gearing particularly for an aircraft propeller shaft 11. wherein the shaft 11, mounted in fixed bearings, is integral with a spider 14 carrying planet gears 27 engaging a driving sun gear 26 and a reaction ring gear 28, the ring gear 28 is splined to a member 29 in turn splined to a supporting ring 31, the splined connections being of small axial extent so that the gear 28 is mounted for radial and swinging movement with respect to the fixed axis of the carrier 14 in order to provide uniform tooth contact. For this purpose also the sun gear 26 is loosely connected to its shaft 24 by splines permitting slight radial movement, and the planet gears 27 are mounted on non-rotatable planetary shafts 37 through spherical bearing races 42 permitting swinging of the gears 27 about their centres. The gearing is thus selfcentring and compensates for twist of the planet carrier. The shafts 37 are clamped between the spider 14 and a rear spider 19 which is bolted thereto and is supported by a bearing 22. In order to prevent rattle in the splined connections 28-29 and 29,31, light wavy springs are lodged between registering circumferential grooves machined in the respective members rearwardly of their interengaging splines. A gear pump 31 supplies oil through a tube 92 to the splines of the sun gear and to a distributer disc 93 provided with two sets of radial passages leading to tubes 97 and passages 102 whereby oil is sprayed on to the gearing and into the hollow shafts 37, where it is trapped and fed to the spherical planet bearings. In order to sense negative torque in the reduction gear-e.g. if the engine fails and the propeller windmills-the ring 31 supporting the ring gear 28 is mounted in a fixed ring 66 by helical splines and is biased rearwardly against a stop ring by springs 71 acting on slidable cups engaging the ring 31. One or more of the cups has a plunger 74 thereon and in the event of negative torque on the ring gear 28 the helical splines cause the ring 31 to move forwardly, against the springs 71, so protruding the plungers 74 which may then actuate mechanism (not shown) to feather the propeller.