Method of manufacturing magnetic body

A method of manufacturing a magnetic body comprising:

• a molding step to pressure-mold a magnetic material into a compact having an H-shaped cross section, constituted by a pair of flange parts that are facing each other and a web part connecting the pair of flange parts;
• a grinding step to turn the compact around a rotational axis being an axis extending from one of the pair of flange parts to the other of the pair of flange parts by passing through the web part, and grind the web part to form a shaft part thereby forming a drum-type ground product having the pair of flange parts on both ends of the shaft part;
• and
• a heat-treatment step to heat-treat the drum-type ground product to obtain a drum-type magnetic body,
• wherein:
• in the grinding step, an outer periphery of a cross section of the shaft part in a direction orthogonal to the rotational shaft is formed by a pair of straight parts that are facing each other and also by a pair of arc parts connecting end parts of the pair of straight parts;
• the flange parts each have an outer principal face running orthogonal to the rotational shaft;
• and
• the pair of straight parts are running in parallel with a longitudinal direction of the outer principal face of the flange part.

A method of manufacturing a magnetic body comprising:

• a molding step to pressure-mold a magnetic material into a compact having an H-shaped cross section, constituted by a pair of flange parts that are facing each other and a web part connecting the pair of flange parts;
• a grinding step to turn the compact around a rotational axis being an axis extending from one of the pair of flange parts to the other of the pair of flange parts by passing through the web part, and grind the web part to form a shaft part thereby forming a drum-type ground product having the pair of flange parts on both ends of the shaft part;
• and
• a heat-treatment step to heat-treat the drum-type ground product to obtain a drum-type magnetic body,
• wherein:
• in the grinding step, the web part is ground to a width narrower than a spacing between outer margin parts that include facing surfaces of the pair of flange parts;
• tapered surfaces are provided on each of the facing surfaces of the pair of flange parts of the compact in such a way that a thickness of each of the flange parts decreases from a side of the web part toward each of the outer margin parts of the flange part;
• and
• in the grinding step, both margins of a ground width are positioned above each of the tapered surfaces.