GB962463A - Improvements in or relating to unitary change speed transmission mechanisms of vehicles - Google Patents

Abstract

962,463. Hydro-mechanical variable-speed gear. REGIE NATIONALE DES USINES RENAULT. Sept. 27, 1960 [Sept. 28, 1959], No. 33215/00. Heading F2D. A combined variable speed and differential gear for a motor vehicle comprises a hydrodynamic torque converter having an input impeller 3, turbine and reaction elements 11, 15 which latter exchange functions for forward and reverse drive, in series with first and second sun-ring planet trains 14, 30 the planet carrier 39 of the latter driving through gears 41, 42 the differential gear crown wheel 47, the torque converter and second epicyclic train being arranged on opposite sides of the differential gear. As shown, the sun and ring gears 25, 14 of the first planet train are connected to the reactor and turbine 15 and 11, respectively, and the planet carrier 28 is connected to the ring 30 of the second planet train which has a reaction sun 33. For low-speed forward one-way drive (reduced-reduced) application of the brake band 18<SP>1</SP> prevents reverse rotation of the reactor 15 and holds the sun 25. The turbine 11 drives the ring 14 of the first planet train, the carrier 28 of which drives at a reduced ratio the ring gear 30 of the second planet train. The planet carrier of the second train reacts on the sun 33 which is held against reverse rotation by a oneway detent 35 and is driven at a further reduced ratio. For two-way low-speed forward drive the sun 33 is held by a brake 36<SP>1</SP>. For two-way intermediate ratio (reduced-direct) a clutch 32 is engaged in addition to the brake 18<SP>1</SP> which former connects the sun and ring gears of the second train which upshifts to direct drive. For high ratio the brake 18<SP>1</SP> is released and the clutch 19 engaged, the clutch 32 remaining engaged, to provide a mechanical drive to the sun 25 of the first train giving overall split torque drive at near one-to-one. For reverse brakes 13<SP>1</SP> and 36<SP>1</SP> are engaged together the latter holding the sun 33 of the second train whilst the former holds the ring gear 14 and the turbine 11. The latter acts as a reactor to drive reversely the reactor 15 which drives the sun 25 of the first train reversely through a oneway detent 16, both gear trains providing reduction ratios. In Fig. 2, not shown, the first gear train precedes the torque converter and its planet carrier is connected to the impeller, its ring gear to the input and the sun gear may be braked for reduced drive or clutched to the ring gear for direct drive in the first, gear train. The clutches and brakes may be hydraulically or electromagnetically operated and a pump 8 supplies fluid pressure to a control circuit (not described). Specifications 831,584 and 919,616 are referred to.