Pre-tightening type auxiliary center device for shaft type workpieces without center holes at ends

The utility model discloses a pre-tightening type auxiliary center device for a shaft type workpiece without a center hole in the end, and belongs to the technical field of machining. The device comprises a taper sleeve and a taper hole sleeve, wherein a plurality of elastic long grooves which are uniformly spaced are formed in the taper sleeve in the circumferential direction; a taper hole for mounting the taper sleeve is formed in the inner center of one side of the taper hole sleeve, and a center hole is formed in the center of the other side of the taper hole sleeve; and the taper sleeve is cooperatively mounted and connected in the taper hole of the taper hole sleeve. An inclined conical surface is arranged on the outer portion of the taper sleeve in the circumferential direction, an inclined taper hole surface is arranged on a taper hole in the taper hole sleeve in the circumferential direction, the taper of the conical surface of the taper sleeve is the same as that of the taper hole surface in the tap