Power transmission apparatus for vehicle

A power transmission apparatus for a vehicle, the apparatus comprising:

• a first input shaft fixedly connected to an engine output shaft fixedly connected to an engine;
• a second input shaft formed as a hollow shaft, mounted coaxial with and external to the first input shaft without rotational interference therebetween, and selectively connectable to the first input shaft;
• a third input shaft formed as a hollow shaft, mounted coaxial with and external to the second input shaft, and selectively connectable to the first input shaft;
• an intermediate shaft and first and second output shafts mounted in parallel with the first, second, and third input shafts;
• an idle shaft mounted in parallel with the second output shaft;
• a planetary gear set having a first rotation element, a second rotation element, and a third rotation element and mounted on an axis of the intermediate shaft, the third rotation element and one of the first and second rotation elements being selectively connectable to the intermediate shaft, the first and second rotation elements being coupled to the third and second input shafts, respectively;
• a plurality of gear sets, each of which is configured to allow at least one torque flow between the intermediate shaft, the first, second, and third input shafts, the first and second output shafts, the idle shaft, and the planetary gear set;
• a first synchronizer mounted on the first output shaft, selectively receiving a first torque from the second input shaft through two paths, and transmitting the received first torque to the first output shaft;
• a second synchronizer mounted on the second output shaft, selectively receiving a second torque from the third input shaft through two paths, and transmitting the received second torque to the second output shaft;
• and
• four clutches.