Hollow shaft welding fixture and method thereof

The invention relates to a hollow shaft welding fixture and a method thereof. Support discs are respectively arranged at the two ends of an I-shaped support frame; three dovetail guide grooves are evenly distributed on the end surfaces of the left and right support discs; each dovetail guide groove is embedded with a fan-shaped slide block capable of sliding along the guide groove; three fan-shaped slide blocks at each side are formed to an inner hole having a taper angle; conical wedges are matched in the inner holes; a first lead screw is rotationally matched with a thread on the I-shaped support frame by penetrating through a through hole in the conical wedge at the right side; the left end of the first lead screw is connected with the conical wedge at the left side; a second lead screw penetrates through the conical wedge at the right side; the conical wedge at the right side is axially positioned on the second lead screw; the second lead screw is rotationally matched with the thread on the I-shaped support frame; a rotating motion of the lead screws drives an axial linear motion of the conical wedges; and the axial linear motion of the conical wedges enables the fan-shaped slide blocks to move on the guide grooves in the radial direction; and the outer circular surfaces of the fan-shaped slide blocks and the inner wall surfaces of parts to be welded generate pressure to realize the clamping so as to adapt to the clamping positioning of different hollow shafts.