TURNING SHAFT, METHOD FOR FORMING TURNING SHAFT, AND COOKING APPLIANCE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a low cost turning shaft which has high working accuracy and mechanical strengths and is integrally formed on a metallic sheet, and a forming method of the same by a simple working process. SOLUTION: The turning shaft 7 is integrally formed on the metallic sheet 1 by a first stage where the half die cutting or forward extrusion is performed by pressing the metallic sheet 1 with a punch 2 and a die 3, a second stage where the projecting part 4 is elongated into a cylindrical shaft shape by backward extrusion by forcing a punch 5 in from the inside of the projecting part 4 after holding the projecting part 4 obtained in the first stage on a die 6a, and a third stage where the forward extrusion is again performed with a punch 8 from the upper surface of the metallic sheet 1 after holding the turning shaft 7 formed in the second stage on a die 9. COPYRIGHT: (C)2005,JPO&NCIPI