Ntn Corporation

Takuji Harano

Shinji Miyazaki

Ikuo Uemoto

Tatsuo Nakajima

Hiroyuki Noda

Toru Takahashi

Natsuhiko Mori

Hiroyuki Hakamata

Takayuki Oda

There is provided a compression-bonded magnet with a case, which can realize high magnetic properties, high corrosion resistance and high durability strength even at low cost. The compression-bonded magnet with a case is a compression-bonded magnet with a case, comprising: a compression-bonded magnetcomprising a rare earth magnet powder such as an isotropic Nd&#x2014;Fe&#x2014;B magnet powder and a resin binder of a thermosetting resin; a casefor inserting the compression-bonded magnet; and a sealing member, wherein the compression-bonded magnetis formed by compression-molding a mixture comprising the rare earth magnet powder and the resin binder into a green compact and curing the resin binder contained in the green compact, the rare earth magnet powder is contained in a large amount with respect to the entire compression-bonded magnet (for example, in a volume ratio of 85% to 90%), the sealing memberis fixed at an insertion opening partof the case, and the compression-bonded magnetis hermetically sealed by the sealing memberand the case

Compression-bonded magnet with case and method for producing the same

The present invention provides a magnetic core having insulating properties, and a method for manufacturing the magnetic core. Provided is a magnetic core manufactured by compression molding and subsequent thermal curing of an iron-based soft magnetic powder having a resin coating formed on particle surfaces thereof. The iron-based soft magnetic powder is one in which the particle surfaces have been coated with an inorganic insulator; the resin coating is an uncured resin coating formed by dry blending the powder with a thermosetting resin at a temperature equal to or greater than the softening point of the thermosetting resin and lower than the thermal curing initiation temperature of the resin; the compression molding is carried out by using a mold to produce a compression molded body; and the thermal curing is carried out at a temperature equal to or greater than the thermal curing initiation temperature of the thermosetting resin.

Magnetic core and method for manufacturing same

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.

Growing community of inventors

Mie, Japan

Takuji Harano