Patent ID: 10486237

Abstract:
A production method for a ring-shaped part is provided with: an inner cutting step for reciprocating a first cutting blade in the radial direction D4 from a state of contact with the center of the thickness of one end 91a of a rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the inner circumferential R1-side of the cylindrical blank 91; an outer cutting step before, after or simultaneously with the inner cutting step for reciprocating a second cutting blade in the radial direction D4 from a state of contact with the center of the thickness of the one end 91a of the rotating cylindrical blank 91 and moving toward the other end 91b in the axial direction D1 to form a semicircular track while cutting the outer circumferential R2-side of the cylindrical blank 91; and a separation step after the inner cutting step and the outer cutting step for cutting the portion 92 of the cylindrical blank 91, the inner circumferential R1-side and the outer circumferential R2-side of which have been cut, from the remainder 93 of the cylindrical blank 91 to obtain a ring-shaped part 94 with a roughly circular cross-section.