Tubing material disconnection device, production manner of ring material and production manner of synchronizer ring material

摘要

PPROBLEM TO BE SOLVED: To improve cutting-off accuracy by bringing a mandrel into uniform close contact with a pipe to be cut-off even if the pipe has ununiform thickness. PSOLUTION: In an apparatus for cutting-off a pipe material, the mandrel 30 is arranged inside a pipe P to be cut-off, and the pipe P is inserted into the die holes 2, 21 of a pair of cutter bodies 1, 20, and is cut-off by sliding both cutter bodies with each other. The mandrel comprises: a cylindrical body 31 having an outside diameter smaller than the inside diameter of the pipe; and a core member 45 arranged in the cylindrical body so as to move in the axial direction. A plurality of elastic pieces 33 are formed on the tip end portion of the cylindrical body at an interval in the circumferential direction so as to elastically deform in the radial direction because of a plurality of longitudinal slits 32. The inner circumferential surfaces of the elastic pieces are formed to be a tapered surface 33a such that the outside diameter of the cylindrical body decreases with the distance toward its end. The core member comprises: a diameter expanding member 34 which is brought into contact with the tapered surface of the elastic pieces, and is moved in the axial direction; and a pressing member 36 for pressing the diameter expanding member. A spherical seat 38a is formed between the diameter expanding member and the pressing member so as to swivelably support the diameter expanding member. PCOPYRIGHT: (C)2009,JPO&INPIT