Power transmission apparatus for a vehicle

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

• a first input shaft selectively connected with the motor/generator;
• a second input shaft formed as a hollow shaft, disposed coaxially with and external to the first input shaft without rotational interference, and selectively connected with the motor/generator;
• a third input shaft formed as a hollow shaft, disposed coaxially with and external to the second input shaft without rotational interference, and selectively connected with the motor/generator;
• a torque mediating shaft formed as a hollow shaft disposed coaxially with and external to the first input shaft without rotational interference;
• 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;
• a first shifting section including a first gear set, a second gear set, a third gear set, a fourth gear set, and a fifth gear set, which are disposed on the first and third input shafts, the first and second intermediate shafts, and the torque mediating shaft, where the first shifting section is configured to selectively receive a torque through the first and third input shafts and to provide a plurality of intermediate shift-stages shifted from the received torque;
• a second shifting section including a planetary gear set having a sun gear fixedly connected with the torque mediating shaft, forming an output torque by combination of a torque selectively transmitted from the first shifting section and a torque selectively input through the second input shaft, the second shifting section configured to output the output torque to an output shaft through one gear set selected among the first, second, third, fourth and fifth gear sets of the first shifting section;
• and
• wherein the output shaft is disposed coaxially with and selectively connected with the second intermediate shaft and outputs a torque received from the first and second shifting sections.