Wheel expansion-contraction device of baby stroller

The invention belongs to the technical field of expansion-contraction devices, and particularly relates to a wheel expansion-contraction device of a baby stroller. The wheel expansion-contraction device comprises a metal plate and a connecting rod, the connecting rod is arranged in the middle of the metal plate, and the metal plate and the connecting rod are welded; the four corners of the metal plate are movably connected with bolts, the obverse side of the connecting rod is fixedly connected with a connecting shaft, and the left end and the right end of the connecting shaft are connected with main movable shafts in an embedded mode; and the right ends of the main movable shafts are fixedly connected with annular plates, the rightmost sides of the annular plates are tightly connected withwheel rotating shafts, wheel bearings are welded to the outer sides of the wheel rotating shafts, and the side walls of the wheel bearings are sleeved with tire bodies. According to the wheel expansion-contraction device of