Output shaft assembly, motor apparatus and wiper motor apparatus

An input disk (28), a clutch disk (38) and wave washers (56) are installed to an output shaft (12) to form an output shaft assembly (10) of a motor apparatus (90). The input disk (28) is axially non-detachable from the output shaft (12) and is rotatable about an axis of the output shaft (12). The input disk (28) is driven by a drive force supplied from a motor main body (92) of the motor apparatus (90). The clutch disk (38) is supported by the output shaft (12) in such a manner that the clutch disk (38) is non-rotatable relative to the output shaft (12) and is axially movable along the output shaft (12) relative to the input disk (28). The wave washers (56) apply a resistive force against axial movement of the clutch disk (38) from a coupled state, at which the input disk (28) is coupled with the clutch disk (38) to rotate together.