Double-row tapered roller bearings have wide variety of structures, 35000 series is used very widely, it has a double-raceway outer ring and two inner rings, there is a flange between two inner rings, when thickness is changed the inner clearance is accordingly changed. When supporting radial load, this kind of bearing can bear double-direction axial load at the same time. Within the range of axial inner clearance, it can confine the axial displacement of shaft and housing.