Hub bearing unit with differentiated inner holes

The utility model discloses a hub bearing unit with differentiated inner holes. The automobile hub bearing unit mainly solves the problem that two inner rings of an existing automobile hub bearing unit are installed in an outer flange side by side, and assembling is troublesome. The bearing is characterized in that the diameter of the first inner hole is smaller than that of the first outer hole, and a first inner ring is arranged in the first inner hole; the second stepped hole mechanism comprises a second outer hole and a second inner hole, the diameter of the second inner hole is smaller than that of the second outer hole, and the second inner hole is provided with a second inner ring; the inner diameter of the first inner ring is smaller than that of the second inner ring. According to the hub bearing unit with the differentiated inner holes, the two inner rings with the different inner diameters are adopted and installed at the two ends of the inner holes of the flange plate, on one hand, installation is