Gears and bearings play an important role in the operation of coal mine machinery. Once the gears and bearings fail to work properly, the whole or the entire equipment will not be able to operate normally. For this reason, the author has intensively studied the gears and bearings of the coal cutter coal cutting section and the gear reducer of the coal conveyor, and looked for the causes of gear and bearing failure, so as to take effective measures to improve the service life of gears and bearings.