Toyota Jidosha Kabushiki Kaisha

Kohei Ishii

Takeshi Hattori

Daisuke Okamoto

Masashi Ohtsubo

Masaaki Tani

Toshimitsu Takahashi

Shinjiro Saigusa

Jung Hwan Hwang

Naoki Iwata

Masashi Hara

Shin Tajima

Kiyotaka Onodera

Kazumichi Nakatani

Junghwan Hwang

Sinjiro Saigusa

Hiroto Nagaki

A method for manufacturing a powder magnetic core, the method including: forming a soft magnetic powder (SMP) layer by putting an SMP having a surface on which an insulating coating film is formed into a space surrounded by a lower punch and a die; forming a pressed powder by compressing the SMP layer in the die by the lower punch and an upper punch; and causing the pressed powder and the die to slide relative to each other and then removing the pressed powder from the die is provided. In forming the SMP layer, a different powder different from the SMP is put into the space before and after the SMP is put into the space and a different powder layer having a spring back rate higher than that of the SMP layer by 0.6-1.1% is formed on upper and lower sides of the SMP layer.

Method for manufacturing powder magnetic core

Provided is a compressed powder core that can suppress a decrease in the inductance even when a high magnetic field (of greater than or equal to 40 kA/m) is applied to the compressed powder core while suppressing an iron loss and a decrease in the strength of the compressed powder core. The compressed powder coreA has soft magnetic particlesA and aluminum nitride layersA formed on the surface layers of the respective soft magnetic particlesA. The compressed powder coreA has a ratio of the first differential relative permeability &#x3bc;'L to the second differential relative permeability &#x3bc;&#x2032;H satisfying a relationship of &#x3bc;&#x2032;L/&#x3bc;&#x2032;H&#x2264;6, and has a magnetic flux density of greater than or equal to 1.4 T when a magnetic field of 60 kA/m is applied. The soft magnetic particles of the compressed powder coreA contain Si in the range of 1.0 to 3.0 mass % and have, when analyzed using XRD, a peak area ratio Sal/Sfe of greater than or equal to 4%, the peak area ratio Sal/Sfe being the ratio of the area Sal of a peak waveform derived from AlN to the area Sfe of a peak waveform derived from Fe.

Compressed powder core, powders for compressed power core, and method for producing compressed powder core

A powder magnetic core having excellent specific resistance or strength. The powder magnetic core has soft magnetic particles, first coating layers that coat the surfaces of the soft magnetic particles and include aluminum nitride, and second coating layers that coat at least a part of the surfaces of the first coating layers and include a low-melting-point glass having a softening point lower than an annealing temperature for the soft magnetic particles. The first coating layers including aluminum nitride are excellent in the wettability to the low-melting-point glass which constitutes the second coating layers and suppress diffusion of constitutional elements between the soft magnetic particles and the low-melting-point glass of the second coating layers. The powder magnetic core can stably exhibit a higher specific resistance and higher strength than the prior art owing to such a synergistic action of the first coating layers and second coating layers.

Powder magnetic core, powder for magnetic cores, and methods of manufacturing them

A soft magnetic member is formed such that, when a differential relative permeability in an applied magnetic field of 100 A/m is represented by a first differential relative permeability &#x3bc;'L, and when a differential relative permeability in an applied magnetic field of 40 kA/m is represented by a second differential relative permeability &#x3bc;&#x2032;H, a ratio of the first differential relative permeability &#x3bc;&#x2032;L to the second differential relative permeability &#x3bc;&#x2032;H satisfies a relationship of &#x3bc;&#x2032;L/&#x3bc;&#x2032;H&#x2264;10, and a magnetic flux density in an applied magnetic field of 60 kA/m is 1.15 T or higher.

Soft magnetic member, reactor, powder for dust core, and method of producing dust core

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Nagoya, Japan

Kohei Ishii