Self-propelled electric vacuum cleaner

1. A self-propelled electric vacuum cleaner comprising; a vacuum cleaner main body; a running section for causing the vacuum cleaner main body to run on a floor; a suction section for suctioning dust; a side brush for sweeping the dust on the floor, to the suction section; a floor detection sensor for detecting whether or not there is the floor; and a control section for controlling and driving the running section, the suction section and the side brush in response to an output of the floor detection sensor, in which the side brush includes a rotating shaft coaxially having a through-hole, and a plurality of brush bundles radially spread from one end of the rotating shaft, wherein the floor detection sensor includes an optical sensor provided adjacent to the other end of the rotating shaft to detect whether or not there is an object, through the through-hole.

2. The self-propelled electric vacuum cleaner of claim 1 further comprising a first gear coaxially and detachably coupled with the other end of the rotating shaft of the side brush; a support section for rotatably supporting the first gear, and a second gear for meshing with the first gear to transmit a rotation force to the side brush, wherein the first gear includes a through-hole communicated with the through-hole of the side brush, and the optical sensor detects whether or not there is the object, through both of the through-holes of the side brush and the first gear.

3. The self-propelled electric vacuum cleaner of claim 1 , wherein the first gear and the second gear compose a worm gear, the first gear being a worm wheel, the second gear being a worm.

4. The self-propelled electric vacuum cleaner of claim 1 , wherein the optical sensor includes an infrared light emitting element and an infrared light receiving element.

5. The self-propelled electric vacuum cleaner of claim 1 , wherein the side brush is exchangeable.