GB369657A - Improvements in friction gearing - Google Patents

Abstract

369,657. Variable-speed friction gearing. GENERAL MOTORS RESEARCH CORPORATION, Detroit, Michigan, U.S.A. Dec. 19, 1930, No. 38370. Convention date, July 21. [Class 80 (ii).] Relates to variablespeed friction gearing having precessional rollers such as 41, Fig. 1, engaging driving and driven toric races such as 36, 35 in which the rollers are mounted on trunnions passing through the centres thereof and adjustable by a control lever, not shown. The invention comprises means incorporated with each trunnion providing an oblique axis about which the roller can tilt to terminate the precessional change in a position of equilibrium. The roller 41 is supported from a fixed spider arm 29a on a positioning arm or lever 72 which rocks in a plane normal to the axis of the gearing about a pivot 76 as described in Specification 369,650. The lever 72 has two flat faces 77, Figs. 4 and 6, nearly but not quite parallel to the section of Fig. 1. Upon the outwardly-set oblique faces 77, inwardly-set faces of trunnion blocks 67, Figs. 4 and 7, are adapted to slide radially and to turn. The blocks 67 are supported in a ring 66 forming the inner race of a ball bearing 65 supporting the roller 41. Fig. 11 is a diagram showing exaggerated the obliquity of the permanently oblique axis TT provided according to the invention normal to the working surfaces 77 of the lever 72. When the lever 72 is rocked by the manual control downwardly of Fig. 11, the point O at which the axis of the roller 41 intersects the gearing axis RR moves to a point O<1> clear of the axis RR. The roller being inclined to circular treads on the toric surfaces, precesses in spiral paths so as to turn on the surfaces 77 about the axis TT until the axis of the roller again intersects the axis RR at a fresh point P. Precession then stops because, in the new position of the rollers, the latter run round and round on circular treads on the toric surfaces.