Ntn Corporation

Ikuo Uemoto

Shinji Miyazaki

Takuji Harano

Toru Takahashi

Natsuhiko Mori

Tatsuo Nakajima

Hiroyuki Noda

Hiroyuki Hakamata

Takayuki Oda

The present invention provides a magnetic core which can be produced with improved productivity without increasing a material cost and has required magnetic and mechanical properties and a process for producing the same. The magnetic core is produced by compression molding and thereafter thermally hardening iron-based soft magnetic powder having resin films formed on surfaces of particles thereof. The resin film is an uncured resin film formed by dry mixing the iron-based soft magnetic powder and epoxy resin containing a latent curing agent with each other at a temperature not less than a softening temperature of the epoxy resin and less than a thermal curing starting temperature thereof. The iron-based soft magnetic powder having the resin films formed on the surfaces of the particles thereof is compression molded by using a die to produce a compression molded body. The compression molded body having the resin films formed on the surfaces of the particles thereof is thermally hardened at a temperature not less than the thermal curing starting temperature of the epoxy resin.

Magnetic core and process for producing same

The present invention provides a composite magnetic core, containing magnetic powders poor in its moldability, which can be configured arbitrarily and has a magnetic characteristic excellent in direct current superimposition characteristics and a magnetic element composed of the composite magnetic core and a coil wound around the circumference thereof. A compressed magnetic body () obtained by compression-molding magnetic powders is combined with an injection-molded magnetic body () obtained by mixing a binding resin with magnetic powders having surfaces thereof electrically insulated and by injection-molding a mixture of the magnetic powders and the binding resin. The compressed magnetic body () is press-fitted into the injection-molded magnetic body () or bonded thereto at a combining portion thereof to obtain the combined body. The combined body is composed of the injection-molded magnetic body () constituting a housing in which the compressed magnetic body () is disposed.

Composite magnetic core and magnetic element

A magnetic encoder device () of the present invention includes a base portion () having a mounting surface () for mounting to a rotary shaft (), a cored bar () fitted and fixed over the base portion (), and a double-row magnetic encoder track () formed on the cored bar (). Through movement of each of magnetic poles of the magnetic encoder track () over a region opposed to a magnetic sensor (), an angle of the rotating rotary shaft is detected. The base portion () is formed of a sintered metal, and the mounting surface () is subjected to sizing.

Magnetic encoder device and rotation detection device

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Mie, Japan

Ikuo Uemoto