LAMINATED STEEL PLATE OF ELECTROMAGNETIC STEEL HAVING HIGH RESISTANCE BETWEEN STEEL PLATES AT SHEAR SURFACE THEREOF, AND METHOD FOR CAULKING THE SAME

摘要

PROBLEM TO BE SOLVED: To carry out caulking of a laminated steel plate without generating breakage of an insulating film when a steel plate having an insulating film on a surface of an electromagnetic steel plate is punched and the punched steel plates are laminated and are fixed with each other by caulking. SOLUTION: A part of an electromagnetic steel plate is pressed into a die with a punch, and a concavoconvex part for caulking is formed in a part of the steel plate. In this case, the clearance between the punch and the die is made to not less than 3% and less than 7% of the steel plate thickness, so that the insulating film comes into intimate contact with the steel plate shear surface to avoid breakage thereof. COPYRIGHT: (C)2008,JPO&INPIT