Powder metallurgy oil-impregnated bearings with gears are widely used bearings. They are made by powder preparation, sintering, and the prohibition of lubricating oil. 

The characteristics of powder metallurgy oil-impregnated bearings with gears are: they are suitable for mass production by manufacturers, do not require cutting processing, save materials, have low prices, lower noise than rolling bearings, and almost do not require lubricating oil, and the oil can penetrate into the sleeve wall. The cost of abrasives is high and it is not suitable for small batch production. 

Powder metallurgy oil-impregnated bearings with gears use the porosity of materials to fill the oil-impregnated bearing material into the lubricating oil, including wood, cast iron, cast copper alloy, and powder metallurgy gear anti-friction materials, as well as oil-impregnated bearing material and lubrication that can uniformly disperse lubricants in the material. The affinity between materials and oil is mainly polymers. Oil-impregnated bearings can reduce vibration, noise, and pollution, and improve the working environment. During operation, a transfer film can be formed to protect the grinding shaft from biting. The grinding shaft requires low hardness, and the oil-impregnated bearings can use unquenched and tempered shafts, which reduces the difficulty of processing related parts.