Dustproof cover for bearing of speed reducer

The utility model relates to the technical field of bearing dust cover mechanisms, in particular to a speed reducer bearing dust cover which comprises a bearing inner ring, a bearing outer ring sleeved outside the bearing inner ring, a steel ball movably connected between the bearing inner ring and the bearing outer ring, and a retainer sleeved outside the steel ball. The retainer is located between the bearing inner ring and the bearing outer ring, a dustproof cover mechanism is arranged between the bearing inner ring and the bearing outer ring, and an oil injection mechanism is movably connected into the dustproof cover mechanism. The rubber sealing gasket is manually pressed, so that a plastic positioning pin on the rubber sealing gasket is inserted into a specified cylindrical groove, the rubber sealing gasket seals a gap, and outside dust is prevented from entering the bearing through protection of a sponge cushion, so that the bearing is prevented from being damaged, and the service life of the bearing