Power transmission apparatus for a vehicle

A power transmission apparatus for a vehicle having an engine and a motor/generator selectively connected to the engine, the power transmission apparatus comprising:

• a first input shaft directly connected with the motor/generator;
• a second input shaft formed as a hollow shaft, disposed coaxial with and external to the first input shaft without rotational interference, and selectively connected with the first input shaft;
• a third input shaft formed as a hollow shaft, disposed coaxial with and external to the second input shaft without rotational interference, and selectively connected with the first input shaft;
• a torque mediating shaft formed as a hollow shaft disposed coaxial with and external to the first input shaft without rotational interference, and selectively connected with the first input shaft;
• a first intermediate shaft disposed in parallel with the first input shaft;
• a second intermediate shaft disposed in parallel with the first input shaft, and selectively connected with a transmission housing;
• first and second idle shafts disposed in parallel with the first input shaft;
• an output shaft disposed in parallel with the first input shaft and coaxially with the second intermediate shaft, and selectively connected with the second intermediate shaft;
• a first shifting section including six gear sets disposed on the first and third input shafts, the first and second intermediate shafts, the first and second idle shafts, and the torque mediating shaft, the first shifting section selectively receiving torque through the first and third input shafts and outputting a plurality of intermediate shift-stages shifted from the received torque;
• and
• a second shifting section including a planetary gear set having a sun gear fixedly connected with the output shaft, forming an output torque by combination a torque selectively transmitted from the first shifting section through the six gear sets and a torque received from the second input shaft, and outputting the output torque to the output shaft.