Tdk Corporation

Yukiharu Kinoshita

Shinichiro Ito

Yutaka Saitoh

Jun Sawai

Hitoshi Iwaya

Hiroyasu Takahashi

Kazuyuki Iimura

Hidekazu Suzuki

Shinitirou Ito

Nobuya Kashiwaba

The present invention provides manganese-zinc-ferrite core fabrication process which can fabricate a manganese-zinc-ferrite core having high surface electrical resistance and low magnetic core losses without recourse to the introduction of nitrogen gas from the outside yet within a short time period, and such a manganese-zinc-ferrite core. To achieve this, manganese-zinc-ferrite core is formed into a given core shape. The core compact is fired in a firing atmosphere having an oxygen concentration controlled with carbonic acid gas and steam. Then, the compact is rapidly cooled at a cooling rate of 350&deg; C./hour to 850&deg; C./hour. In this way, a manganese-zinc-ferrite core is obtained.

Process of fabricating a manganese-zinc-ferrite core, and manganese zinc-base ferrite core

A core for a deflecting yoke for a CRT includes a first aperture at a neck portion side having a circular configuration, and a second aperture at a funnel portion side, an inner periphery of the second aperture at an edge surface thereof having two major sides and two minor sides. The major sides contain a first circular segment of which a radius is 200 mm or larger and has a radius of which a center exists off a center of the funnel portion and an amount at which the first circular segment occupies the major sides is over 50%. The minor sides contain a second circular segment of which a radius is 100 mm or larger and has a radius of which a center exists off a center of the funnel portion and an amount at which the second circular segment occupies the minor sides is over 40%. The two major sides and the minor sides are tangential to circular segments at four corners thereof.

Core for deflecting yoke

Coil device

A method for adjusting inductance of a coil device of a closed structure wherein the coil device outside magnetic substance forming an endless loop, an inside magnetic substance formed inside of the outside magnetic substance and a coil wound on the periphery of the inside magnetic substance. The coil device further includes gaps between both ends of the outside magnetic substance and the inside magnetic substance, and notches or holes in the outside magnetic substance. In adjusting the inductance of the coil device, a jig is inserted through the notches or holes so as to shift the position of the inside magnetic substance with respect to the outside magnetic substance.

The variable inductance coil device having an outer magnetic member, a bobbin member, a coil member and an inner magnetic member. A female thread (thread portion) is provided in the inner periphery of the tube of the bobbin member, and a male thread (thread portion) which meets with the female thread of the tube is provided in the outer periphery of the inner magnetic member. The inductance varies accurately by rotating and moving the inner magnetic member. Since the outer magnetic member is formed in the closed shape, the leakage flux can be lowered.

Variable inductance coil device

The present invention is comprised of an outside magnetic substance forming an endless loop, an inside magnetic substance formed inside of said outside magnetic substance and coil wound on the periphery of said inside magnetic substance. In a coil device of the present invention with gaps between both ends of said outside magnetic substance and said inside magnetic substance, notches or holes are provided in said outside magnetic substance for the purpose of inserting insert a jig therein so as to adjustably move the position of said inside magnetic substance, wherein said notches or holes correspond to the gaps provided in both ends of said inside magnetic substance. In said coil device, the inside magnetic substance can be adjusted and moved its position by pressing a bar-like jig through the notches or the holes provided in the outside magnetic substance. Thus, it has become possible to adjust the value of the inductance by about 25% experimentally.

Adjustment system for a coil device

The present invention provides a coil device including magnetic cores having gap regions and a coil wound to contain the gap regions. The present invention provides an improvement in which a shape of at least one of the opposing magnetic cores forming the gap regions is formed into a curve of logarithmic function from its base end to its extreme end, its most extreme end is provided with a gap adjusting flat surface and then a plurality of gaps are formed in the gap regions. With such an arrangement as above, the present invention provides the coil device capable of reducing a leakage magnetic flux produced around the gaps, preventing an abnormal generation of heat of the coils and further preventing a bad influence of noise against a peripheral apparatus.

A coil device includes two magnetic cores each having a U-shape in section forming a closed magnetic path therein with their legs being opposed to each other and having a gap in such path, and a coil wound so as to cover the gap. In this structure, the mutually opposed portions of the magnetic cores in the region to form the gap are so shaped that the cross-sectional area of the fore end becomes smaller than that of the base end, thereby preventing concentration of any leakage magnetic flux on the gap portions while averting abnormal generation of heat in the coil to consequently eliminate harmful influence of noise on peripheral apparatus or components.

Growing community of inventors

Tokyo, Japan

Yukiharu Kinoshita