Power transmission apparatus for hybrid electric vehicle

A power transmission apparatus for a hybrid electric vehicle having an engine and a motor as power sources, the power transmission apparatus comprising:

• an engine output shaft receiving a torque of the engine;
• an input shaft coaxially disposed with the engine output shaft;
• first and second output shafts formed as hollow shafts coaxial with the input shaft, and respectively disposed at forward and rearward sides of the input shaft without rotational interference;
• a third output shaft formed as a hollow shaft and coaxially disposed with the first output shaft without rotational interference;
• a shared clutch drum disposed at the forward side of the input shaft, and having a motor gear formed on an exterior circumference of the shared clutch drum, wherein the motor gear is externally gear-meshed with the motor, and the shared clutch drum has an interior circumference rotatably supported by a supporting end formed at a radially interior side of a front cover, and is connected to the input shaft through a connection plate;
• an engine clutch arranged on the interior circumference of the shared clutch drum and configured to selectively transmit a torque between the engine output shaft and the input shaft;
• first and third clutches disposed in two rows in a radial direction within the interior circumference of the shared clutch drum and configured to selectively transmit the torque of the input shaft to the first and third output shafts, respectively;
• a planetary gear set disposed on the second output shaft and including a ring gear spline-engaged with the second output shaft through a connection ring;
• and
• a second clutch disposed radially external to the planetary gear set and selectively connecting the input shaft and a sun gear of the planetary gear set.