GB680663A - A hydraulic transmission mechanism - Google Patents

Abstract

680,663. Hydro-mechanical variable-speed gear. CHATELET, H. J. G. April 10, 1951 [April 14, 1950], No. 9196/50. Class 80 (ii). [Also in Group XXIX] A hydraulic transmission mechanism utilizable on automotive vehicles between a driving shaft 2 and a driven shaft 16 for providing with a minimum of slippage progressively varying speed according to the rate of rotation of the motor and the resistant torque comprises a primary hydraulic coupling 20-21, a secondary hydraulic coupling 24-25 exerting a brake action, and a planetary gear train, the runner 21 of the primary coupling being rigid with the driven shaft 16 together with an element of the gear train, the impeller 20 being rigidly connected to a second element of the gear train together with the runner 24 of the secondary coupling, and the impeller of the latter being rigid with the driving shaft 2 together with a third element of the gear train, so that the reaction normally exerted upon the impeller of the primary hydraulic coupling due to the transmission of the driving torque through the gear train is braked by the co-operation of the impeller and the runner of the secondary hydraulic coupling. The driving shaft 2 is secured to a plate 3 carrying a casing 5-6. Fixed to the casing 5 are vanes 25 and the sun wheel 10 of the planetary gear, which wheel meshes with planet wheels 13 supported by a carrier 14 secured on the driven shaft 16 having the runner vanes 21 fastened thereto. The ring member 18 of the planetary gear is secured to the impeller 20 which carries the vanes 24. When the engine driving the shaft 2 is idling, the shaft drives the vanes 25 and the sun wheel 10, and since the carrier 14 is held against rotation by the inertia of the stationary shaft 16, the impeller 20 is caused to rotate in a reverse direction to that of the shaft 2. Since the vanes 24 will therefore rotate in the reverse direction to the vanes 25 they will have a braking effect. Increase in engine speed results in the interaction between the vanes 24-25 slowing down the impeller 20, the consequent increased torque on the gear carrier 14 overcomes the inertia of the shaft 16 and this shaft together with the runner 21 commence to rotate in the same direction as the shaft 2. After a time the ring member 18 stops, then is driven in the same direction as the shaft 2, and thereafter the transmission ratio between the shafts 2. and 16 tends to unity.