Shaft assembly, apparatus for shading window and apparatus for luggage screen of automobile having shaft assembly

A shaft assembly, including:

• a shaft connected to a blind sheet and performing rotational movement between a deployed position and a retracted position of the blind sheet;
• a pair of end caps each being coupled to one side and the other side of the shaft to perform the rotational movement together with the shaft;
• a gear unit connected to either one of the pair of end caps and has a plurality of gears to interlock with the rotational movement of the shaft between the retracted position and the deployed position of the blind sheet and provide the shaft with a rotational movement force between the deployed position and the retracted position of the blind sheet;
• and
• an elastic unit connected to any one of the plurality of gears of the gear unit and providing an elastic force so that the gear unit provides a rotational driving force to the shaft between the deployed position and the retracted position of the blind sheet.