Rotor coupling self-alignment device and method for mixed-flow water-turbine generator set

The invention relates to a mixed-flow type water-turbine generator set rotor coupling self-alignment device and method, the mixed-flow type water-turbine generator set rotor coupling self-alignment device comprises a pin seat, an expansion pin cylinder, a taper pin body and a compression nut which are installed in a matched mode to form an expansion pin set, the diameter of the expansion pin cylinder is small when the expansion pin set is in a natural state before the compression nut is screwed, and the expansion pin cylinder can be conveniently placed into a pin hole which is not completely aligned and has dislocation. After the compression nut is screwed tightly, the pin seat and the taper pin body are stressed and pushed to enable the expansion pin barrel to expand, the diameter of the expansion pin barrel is increased, the rotor is aligned with a pin hole of a generator shaft, and the expansion pin set is used as a connecting pin, so that mounting and dismounting are convenient. During installation, the c