Automatic transmission for hybrid vehicle

An automatic transmission for a hybrid vehicle having an internal combustion engine and an electric motor, which processes the rotation of an input shaft, to which the power of the internal combustion engine is transmitted, into speeds of a plurality of gear shift stages through the intermediary of a plurality of gear trains and outputs the resulting rotation from an output member, the automatic transmission comprising:

• a first drive gear shaft rotatably supporting a drive gear of each gear train which establishes a gear shift stage of an odd ordinal in a transmission gear ratio rank order;
• a second drive gear shaft rotatably supporting a drive gear of each gear train which establishes a gear shift stage of an even ordinal in a transmission gear ratio rank order;
• a first clutch that disconnectably connects the input shaft and the first drive gear shaft;
• a second clutch that disconnectably connects the input shaft and the second drive gear shaft;
• a first meshing mechanism, which selectively connects a drive gear of each gear train which establishes a gear shift stage of an odd ordinal in a transmission gear ratio rank order, to the first drive gear shaft;
• a second meshing mechanism, which selectively connects a drive gear of each gear train which establishes a gear shift stage of an even ordinal in a transmission gear ratio rank order, to the second drive gear shaft;
• a planetary gear mechanism having three elements, namely, a sun gear, a carrier, and a ring gear;
• the three elements composed of the sun gear, the carrier, and the ring gear of the planetary gear mechanism being defined as a first element, a second element, and a third element, respectively, in an order of the arrangement at intervals corresponding to gear ratios in a velocity diagram;
• a brake which disengageably locks the third element to a transmission case;
• and
• a switching mechanism which switches between a state in which a rotor of the electric motor is connected to the first element of the planetary gear mechanism and a state in which the rotor of the electric motor is connected to the third element of the planetary gear mechanism,
• wherein the first element and the first drive gear shaft are connected, and
• the second element and one of drive gears rotatably supported by the first drive gear shaft are connected.