GB793318A - Improvements in and relating to power transmission arrangements including epicyclic change speed gearing - Google Patents

Abstract

793,318. Change-speed gearing. SELF-CHANGING GEARS, Ltd. Dec. 29, 1955 [Aug. 8, 1955], No. 22746/55. Class 80 (2). A first gear unit comprising a number of epicyclic trains, the reaction elements of which are controlled by brakes to afford a number of ratios, is followed or preceded in series by a second gear unit comprising two epicyclic trains, the reaction elements of which are controlled by brakes to afford two ratios, which latter may be two reduction ratios or two overdrive ratios or a reduction ratio and an overdrive ratio. As shown, the first unit affords four forward speeds and reverse between an input shaft 13 and an intermediate shaft 1. The first, second and third speeds are obtained by braking the annuli 8, 9 and the sun 11, respectively, of three opicyclic trains 4, 5, 6, direct drive is afforded by a clutch 14 and reverse by braking the annulus of a fourth epicyclic train 15. The sun 18 of one train of the second unit is secured to shaft 1, its carrier 20 is secured to an output shaft 3, while. its annulus 23 is adapted to be braked to afford a reduction ratio. The carrier 20 is also connected to the annulus 25 of the other train, whose carrier 27 is connected to sun 18 and whose sun 28 is adapted to be braked at 29 to afford an overdrive ratio. The brakes are all of band type actuated by fluid pressure, two bands acting simultaneously to provide a wrapping effect for both directions of rotation being provided for annulus 23. According to the Provisional Specification, the second unit may comprise a single epicyclic train with a clutch and a brake for the reaction element, to afford direct drive and a reduction or overdrive ratio. Specification 164,042, [Class 80 (ii)], is referred to.