The present invention relates to an automatic transmission provided with an overdrive device of the type in which a torque converter, an automatic transmission and a final reduction gear are integrally assembled, and more particularly relates to an automatic transmission which is directly connected with an engine in the overdrive condition.
In a conventional automatic transmission with an overdrive device, power from the engine crankshaft is transmitted to an overdrive device through a torque converter even in the overdrive condition. In such construction it has been impossible to attain as low a fuel consumption as with a manual transmission, because of transmission loss due to the torque converter in the overdrive condition. Further, planetary gears are generally used for a gear mechanism of the overdrive device, since the power transmission flow is arranged on the axis. Such a construction makes the apparatus large and complicated. Also the apparatus should be provided with at least two pairs of transmission elements, which cause complication of the hydraulic control system.
USPTO Backgrounds
USPTO Backgrounds