Disclosed is a unidirectional clutch, comprising a starting gear (11), a transmission component (13) sleeved at one end of the starting gear (11), a housing (12) covering one side of the transmission component (13), a washer (18) provided between a shaft shoulder (21) of the starting gear (11) and the housing (12), and an elastic washer (20) provided between the shaft shoulder (21) and the washer (18), wherein the washer (18) is used for limiting an axial movement of the starting gear (11), the transmission component (13) is provided with a curved cavity (17), the curved cavity (17) is provided with a lubricating grease, and the elastic washer (20) is used for preventing the lubricating grease from flowing out of the curved cavity (17).