GB887133A - Improved variable-speed power transmission mechanisms - Google Patents

Abstract

887,133. Hydro-mechanical variable-speed gear. GENERAL MOTORS CORPORATION. May 24, 1960 [June 10, 1959], No. 18220/60. Class 80 (2). In a combined torque converter and planet gear an input shaft 10 is connected to an impeller 12 and to a sun 27 of a first sun-ring planet train, a first turbine 14 is connected to an output-connected carrier 23 of said first train for forward drive throughout the operation, and a second turbine 15, connected to a sun 34 of a second sun-ring planet train having a carrier 36 reacting on a one-way detent 38 and to a first train ring 28 through a one-way clutch 32, is reversely driven at low impeller speeds to forwardly drive, at reduced speed and increased torque, an output-connected second train ring 41, thereby augmenting turbine 14 torque, and is forwardly driven at high impeller speeds to forwardly drive the first train ring 28, the carrier 36 over-running, to provide, with the input-connected sun 27, a split torque drive augmenting turbine 14 torque. A reactor 16 reacts on a one-way detent 17. At converter coupling stage the turbines approach a common speed and a split torque drive having a high proportion of direct mechanical torque is provided. A direct drive clutch 45 is provided between input and output shafts 10, 24. The planet trains may be positioned rearward (Fig. 2, not shown), or, as shown, forward of the torque converter and may be spaced therefrom. The incidence of the second turbine 15 blades is variable during operation. An increase (or decrease) in the ratio of the second planet train lowers (or raises) the overall speed ratio at which the speed of the second turbine stops increasing in a negative direction and provides a higher (or lower) stall torque ratio and a higher (or lower) torque ratio over a shorter (or longer) initial speed ratio range. Increasing (or decreasing) the ratio of the first planet train decreases (or increases) the torque transmitted by the sun 27 assuming the same torque from the second turbine 15. The Specification includes graphs in respect of torques, speeds and efficiencies. Details are also provided in respect of ratios of the planet gear trains and torque converter blade angles.