Key groove machining alignment device for double-key-groove gear shaft and alignment method of key groove machining alignment device

The invention relates to the technical field of machining, in particular to a key groove machining alignment device for a double-key-groove gear and an alignment method of the key groove machining alignment device. The key groove machining alignment device and method are suitable for positioning alignment machining of double key grooves after tooth profile machining is completed on a gear shaft on a planer type milling machine. The key groove machining alignment device for the double-key-groove gear shaft comprises equal-height supporting blocks, an angle template, a core rod and a dial indicator. The two sets of equal-height supporting blocks are horizontally supported on the workbench, the positioning grooves formed in the workbench in advance and the positioning keys at the bottoms of the bottom plates of the equal-height supporting blocks are rapidly assembled so that the axial direction and the horizontal direction of the gear shaft can be fixed, and the direction of a key groove to be machined can be al