GB1479750A - Torque converter transmissions - Google Patents

Abstract

1479750 Change-speed gear GKN TRANSMISSIONS Ltd 12 Nov 1975 [21 Nov 1974] 50415/74 Heading F2D A hydrodynamic torque converter comprising at least three elements is combined with three epicyclic gearsets each consisting of an annulus or ring gear, a sun, and a carrier with two or more planets, a first of the gearsets having two of its members directly connected to two elements of the converter for controlling the performance of the latter, the second and third gearsets providing forward/reverse drive and high/low range, all of the suns being coaxial, and corresponding members of each gearset having the same number of teeth on the same pitch circle diameter. In one arrangement the ring gear 19 of the first gearset is connected to the reaction member 16 of the converter and the sun 20 is connected to turbine 15. The planet carrier 22 may be braked so that the reaction member is driven backwards to provide low range, the ring gear and reaction member may be braked to establish intermediate range, or the turbine may be clutched to the input 17 for direct drive or high range. The turbine drives the sun 23 of the second gearset of which the carrier 32 may be clutched to the sun or braked to impart forward or reverse drive to the ring gear 24 which has a direct connection with the ring gear 25 of the third gearset, the carrier 30 of the latter constituting the output member and low or high range being established by braking the sun or locking the train by clutching the sun to the ring gear. In a modification the sun of the first gearset is connected to the impeller instead of to the turbine, whilst in another arrangement the turbine is connected to the carrier of the first gearset, the reaction member is connected through a one-way clutch to the sun, and the ring gear provides the input to the second gearset. This arrangement provides only two ranges for the converter/first gearset combination, as does another arrangement in which the first gearset precedes the converter, the input being connected to the carrier, the ring gear to the impeller, the sun to the turbine which provides the input to the second gearset, and the reaction ring having a one-way clutch connection with a fixed part of the apparatus. A further modification of the converter/first gearset combination, providing three ranges, has a converter with two reaction members one of which is connected through a one-way clutch to a fixture and the other to the sun of the first gearset, the impeller is driven directly by the input, and the turbine is connected to the ring gear and provides the input to the second gearset. In all of these modifications, and also in other known converter/first gearset combinations which are illustrated, including two with two turbines, the arrangement of the second and third gearsets is unaltered. The brakes and clutches are multiplate units actuated hydraulically.