Patent ID: 7415757

Claim:
A method for manufacturing a coil-embedded dust core in which an air-core coil is embedded in a green body with use of a die machine comprising a upper die set including an upper die and a top punch ascending and descending inside said upper die, and a lower die set including a lower die and a bottom punch ascending and descending inside said lower die, said method comprising in order steps of: (a) charging soft magnetic metal powder including an insulation material, composing said green body, into a cavity of said lower die equipped with a tubular member, which has a top portion in substantially the same shape as the plane shape of said air-core coil, in said bottom punch to be ascendable and descendable; (b) placing said air-core coil concentrically with said tubular member in a state in which it ascends to a predetermined position, inside the cavity of said lower die with said soft magnetic metal powder being charged therein; (c) lowering said upper die to said lower die, and further charging said soft magnetic metal powder into a cavity of said upper die so as to cover said air-core coil; and (d) compacting said soft magnetic metal powder in an axial direction of said air-core coil by relatively lowering said top punch with respect to said bottom punch.