Formation manner of coil bobbin and coil bobbin and die null for its injection molding

摘要

PURPOSE: To prevent an occurrence of a weld line and an air pocket in a cylindrical body part by a method wherein in a coil bobbin consisting of a cylindrical body part, flange parts provided on both ends of the body part, and leg parts provided on the lower surface of one of the flange parts, the other flange part apart from the leg parts has a part made of thick-wall parts and thin-wall parts to be connected to the body part. ;CONSTITUTION: Flange parts 2, 3 are provided on the upper and lower ends of a cylindrical body part 1. Leg parts 4, 5 are provided on the lower surface of the flange part 3. In the flange part 2 having a cylindrical hollow part of approximately a trapezoidal shape, thin-wall parts 21 are provided on parts along chevron-shape long oblique lines, and thick-wall parts 22 are provided on the other parts. From an abutting part, which is a joint between the upper end of the cylindrical body part 1. and the lower part of the flange part 2, to the outer end of the flange part 2, the upper surface of the thin-wall part 21 is unlevelly disposed to be lower than the upper surface of the thick-wall part 22, and the lower surfaces of the thick-wall part 22 and the thin-wall part 21, i.e., the lower surface of the flange part 2, are disposed to be flush with each other. The flush lower surface of the flange part 2 ensures the uniform contact of a conductor with the lower surface of the flange part 2, which realizes a uniform electromagnetic coil.;COPYRIGHT: (C)1993,JPO&Japio