Bearing clearance adjusting device and gear reducer

The invention relates to the field of bearings, and discloses a bearing clearance adjusting device and a gear reducer, the bearing clearance adjusting device comprises a double-row tapered roller bearing component, the double-row tapered roller bearing component is provided with an inner ring, an outer ring and tapered rollers, the outer side of the inner ring is provided with a tapered roller path, a transmission shaft and a box plate, and a bearing groove is formed in the middle of the box plate; the double-row tapered roller bearing component is installed in the bearing groove and used for installation of the double-row tapered roller bearing component, and an installation groove is formed in the front side of the box plate. Compared with the prior art, after the double-row tapered roller bearing part is installed and placed, the outer ring on one side can be extruded through pressing and fixing of the pressing outer ring, meanwhile, under the driving action of the adjusting parts on the two sides, the out