Power transmission apparatus for a vehicle

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

• a first input shaft selectively connected with the motor shaft;
• a second input shaft, the second input shaft being hollow and disposed coaxially with and exterior to the first input shaft without rotational interference, and selectively connected with the motor shaft;
• a third input shaft, the third input shaft being hollow and disposed coaxially with and exterior to the second input shaft without rotational interference, and selectively connected with the motor shaft;
• a power mediating shaft, the power meditating shaft being hollow and disposed coaxially with and exterior 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;
• an idle shaft disposed in parallel with the first input shaft;
• a first shifting section including six gear sets disposed on the first and third input shafts, the first and second intermediate shafts, the idle shaft, and the power mediating shaft, the first shifting section selectively receiving a first torque through the first and third input shafts and outputting a plurality of intermediate shift-stages shifted from the first torque;
• a second shifting section including a planetary gear set having a sun gear fixedly connected with the power mediating shaft, forming a third torque by combination of the first torque selectively transmitted from the first shifting section and a second torque received from the second input shaft, and outputting the third torque to an output shaft;
• and
• the output shaft disposed on a same axis with the second intermediate shaft, selectively connected with the second intermediate shaft, and outputting the third torque received from the first and second shifting sections.