Patent ID: 6967423

Claim:
A brushless alternator field coil bobbin apparatus comprising: a thick ring-shaped yoke portion; a plate comprising: a cylindrical portion; and a disk-shaped flange portion disposed so as to extend radially outward from a first end of said cylindrical portion; and a bobbin onto which a field coil is wound, wherein a stepped portion is recessed into an inner circumferential surface of said yoke portion so as to extend axially for a predetermined length from a first end of said yoke portion, a second axial end portion of said cylindrical portion of said plate is fitted into said stepped portion so as to be placed in close contact with an inner circumferential surface thereof and is welded to said yoke portion, and said bobbin is mounted into a space formed by said yoke portion and said plate; and wherein said second axial end portion of said cylindrical portion of said plate is formed into a tongue segment having a predetermined circumferential width and projecting axially outward, and said stepped portion is formed to a circumferential width and an axial length that fit together with said tongue segment.