Combined grinding wheel for ultrasonic machining and design method therefor

A combined grinding wheel for ultrasonic machining, comprising:

• an outer grinding ring, an upper end thereof having a center taper hole and a plurality of outer grinding ring water holes located at a circumferential outer side of the center taper hole, and a lower end thereof having an outer grinding ring cavity communicated with the center taper hole and the outer grinding ring water holes, wherein a lower end of the outer grinding ring cavity is open, and an outer wall of the outer grinding ring corresponding to the outer grinding ring cavity has a plurality of outer grinding ring chutes communicated with the outer grinding ring cavity, wherein a rabbet of the outer grinding ring chute is located at a lower end face of the outer grinding ring;
• a connecting taper shank, a lower end thereof having a shank portion inserting into the outer grinding ring cavity from the center taper hole and matching a tapered surface of the center taper hole, wherein the outer wall of a tapered section of the shank portion located in the outer grinding ring cavity is in thread connection with a tapered or circular nut, and an upper end face of the nut fits with an inner wall of an upper end of the outer grinding ring cavity;
• a connecting flange located outside the shank portion and fixed on the inner wall of the upper end of the outer grinding ring cavity, and having a center tapered through hole;
• and
• an inner vibration unit having a tapered surface matching a tapered surface of the center tapered through hole and a center hole connected with the connecting taper shank by means of a screw.