Transmission system of hybrid electric vehicle

A transmission system of a hybrid electric vehicle comprising:

• a first shaft connected to an engine and provided with a first externally-meshing gear fixedly disposed on the first shaft;
• a first hollow shaft disposed without rotational interference with the first shaft and selectively connectable to the first shaft through a clutch;
• a second hollow shaft disposed without rotational interference with the first hollow shaft, wherein the first shaft is positioned through the first hollow shaft to form a combination, and the combination of the first shaft and the first hollow shaft are positioned through the second hollow shaft;
• a second shaft disposed in parallel with the first shaft and provided with a second externally-meshing gear fixedly disposed on the second shaft and engaged with the first externally-meshing gear;
• first and second output gears fixedly disposed respectively on the first and second hollow shafts and respectively outputting torques of the first and second hollow shafts;
• a first motor/generator directly and operably connected to the second hollow shaft;
• a second motor/generator directly and operably connected to the second shaft;
• and
• a reduction gear unit transmitting the torque of the first hollow shaft or the second hollow shaft to a differential apparatus.

A transmission system of a hybrid electric vehicle comprising:

• a first shaft connected to an engine and provided with a first externally-meshing gear fixedly disposed on the first shaft;
• a first hollow shaft disposed without rotational interference with the first shaft and selectively connectable to the first shaft through a clutch;
• a second hollow shaft disposed without rotational interference with the first hollow shaft;
• a second shaft disposed in parallel with the first shaft and provided with a second externally-meshing gear fixedly disposed on the second shaft and engaged with the first externally-meshing gear;
• first and second output gears fixedly disposed respectively on the first and second hollow shafts and respectively outputting torques of the first and second hollow shafts;
• a first motor/generator directly and operably connected to the second hollow shaft;
• a second motor/generator directly and operably connected to the second shaft;
• and
• a reduction gear unit transmitting the torque of the first hollow shaft or the second hollow shaft to a differential apparatus,
• wherein the first shaft is positioned through the first hollow shaft to form a combination, and the combination of the first shaft and the first hollow shaft are positioned through the second hollow shaft.