Carrier roller replacing device

The carrier roller replacing device comprises an upper supporting rod, a lower supporting rod, a middle power rod, a main support and a motor, an outer gear surrounding the outer side wall of the middle section of the middle power rod by a circle is fixedly arranged on the outer side wall of the middle section of the middle power rod, external threads are arranged at the two ends of the middle power rod, and an upper shaft sleeve and a lower shaft sleeve which are opposite in rotation direction are rotationally sleeved with the two ends of the middle power rod respectively; the upper end of the upper shaft sleeve is fixed to the bottom of the upper supporting rod. The lower end of the lower shaft sleeve is fixed to the top of the lower supporting rod. The main support is of a transverse U-shaped structure, supporting rings are arranged at the two tail ends of the main support respectively and correspondingly arranged on the outer sides of the upper shaft sleeve and the lower shaft sleeve in a sleeving mode, t