The overrunning clutch is a mechanical component that achieves the function of self-clutching and self-clutching by using the change of speed or rotation direction of the main and driven parts. It is the basic component in the mechanical transmission of mechatronics. Its connection forms are divided into: key connection, bolt connection, gear connection, pulley connection, sprocket connection and so on. Its main function is to prevent reversal, precise positioning, transfer or cut off the torque. Therefore, some industries call it backstop or one-way bearings. Widely used in automobile automatic transmission, motorcycle electric starting, electric bicycle, machine tools, packaging machinery, printing machinery, light industry machinery, textile machinery, petrochemical machinery, cement machinery, gold treatment machinery, lifting and transportation machinery, reducer, power generation equipment and test bed mechanical transmission.