GB721365A - Improvements in or relating to transmissions for motor vehicles - Google Patents

Abstract

721,365. Hydromechanical variable-speed gear. ZAHNRADFABRIK FRIEDRICHSHAFEN AKT.-GES. Feb. 11, 1952 [Feb. 10, 1951], No. 3544/52. Class 80 (2). A torque converter and a stepped ratio gear box are operable in series in two ratios (first and third) of the four available all of which may be utilized when the converter is bridged by a clutch. As shown in Fig. 1 the converter pump P is connected to an engine-driven shaft M together with a gear wheel 1 meshing with a wheel 2 which may be clutched at 22, 23 to a countershaft 20. The turbine T of the converter is also connected, through a one-way clutch 18 and a gear pair 16, 15, to the countershaft 20. The converter may be bridged by engaging the clutch 22, 23. Clutches 4, 5; 10. 11; 24, 25 are engageable to select the appropriate gear ratio by combinations of the gear pairs 1, 2; 16, 15; 8, 21 and 17, 27. Top gear provides a direct drive from the input shaft M to the output shaft 12. In the modification shown in Fig. 3 the gear box comprises three gear pairs only. A clutch member 34 on the engine shaft M may be engaged with a clutch member 33 mounted, together with a wheel 32, on the converter turbine shaft 31 to bridge the torque converter. The clutch member 34 is also engageable with a member 35 the remainder of the gearing being identical with that of Fig. 1. In each case the guide wheel L of the converter is connected through a one-way clutch to a stationary housing. The ratios of the wheel pairs 1, 2 and 16, 15 in Fig. 1 may be so chosen that the speed of the output shaft 12 for any given engine speed is the same whether the torque converter is in use or not. This compensates for slip in the converter. The gear-box may be of the overdrive type to reduce its size, an increased reduction being provided between the gear-box and the vehicle axle.