Murata Manufacturing Co., Ltd.

Takaaki Ooi

Tatsuyuki Yamada

Kouichi Yamaguchi

Iwao Fukutani

Hisato Oshima

Kiyoteru Igashira

Yoshie Nishikawa

Yoshimi Tanaka

Toshinori Murakami

Shingo Okuyama

Takeshi Tanabe

Koichi Yamaguchi

Toru Tominaga

Kenichi Saito

Kenji Naito

Yoshihiro Sako

Makoto Matsubara

Hideki Kumatani

Koji Yokoo

Yukichi Sakurai

An antenna coil includes a wound body including a magnetic core, a bobbin surrounding the magnetic core, and a coil wound around the bobbin, a case in which the wound body is placed, and a foam disposed in a gap between the wound body and the case. The foam is compressed at a rate of about 45% to about 65% on the basis of a thickness of the foam in a non-load state. The antenna coil prevents breakage of the magnetic core and is suitable for use in a short-distance communication system in an LF-band.

Antenna coil

In a noise filter, an input side of a signal-line lead is inserted in a first substantially cylindrical ferrite bead, and an output side of the signal-line lead is inserted in a second substantially cylindrical ferrite bead. An input side of a ground lead is inserted in a third substantially cylindrical ferrite bead. The signal-line lead is inserted in a feedthrough capacitor such that the feedthrough capacitor is adjacent to an output side of the second substantially cylindrical ferrite bead. A multilayer capacitor is electrically coupled between the signal-line lead and the ground lead such that the multilayer capacitor is adjacent to an output side of the first substantially cylindrical ferrite bead and adjacent to an output side of the third substantially cylindrical ferrite bead. Each of an end of the signal-line lead and an end of the ground lead is flat, bent along an outer surface of a base member, and defines a surface-mount external terminal.

Noise filter having filter components fitted into depressions in a base member

A noise filter includes a capacitor having a hot side input terminal, a hot side output terminal, a ground side input terminal, and a ground side output terminal. A circuit board includes a hot side input electrode connected to the hot side input terminal, a hot side output electrode connected to the hot side output terminal, a ground side input electrode connected to the ground side input terminal, and a ground side output electrode connected to the ground side output terminal. The impedance of the ground side input terminal seen from the ground side output electrode is larger than both the impedance of the ground side output terminal seen from the ground side output electrode and the impedance of the hot side output terminal seen from the ground side output electrode. For this purpose, a stray capacitance formed between the ground side input electrode and the ground side output electrode is reduced by increasing a gap therebetween. Accordingly, excellent noise-reducing characteristics are provided.

Noise filter mounting structure

A first winding of a choke coil is closely wound in a single layer on the outer periphery of a substantially cylindrical body portion of a first bobbin. A second winding is closely wound in a single layer over the first winding. A third winding is closely wound in a single layer on the outer periphery of a substantially cylindrical body portion of a second bobbin. A fourth winding is closely wound in a single layer over the third winding. The first, second, third and fourth windings are wound so as to mutually strengthen magnetic fluxes when an in-phase noise current flows. The first and second windings are connected to a pair of signal lines via which differential transmission communication is performed and on which a power supply current is sent out. The third and fourth windings are connected to a pair of signal lines via which differential transmission communication is performed and on which the power supply current returns. Thus, a circuit including a compact choke coil having large inductance and better high-frequency characteristics, and the choke coil is provided.

Circuit using choke coil and choke coil

A surge absorber includes a laminated compact of a first ceramic green sheet having a first internal electrode film extending to both sides thereof, a second ceramic green sheet having an second internal electrode film extending to both end surfaces thereof, and a third ceramic green sheet having a discharge hole. Ground external electrode layers are provided on both sides of the laminate so as to be connected with both ends of the first internal electrode film, and signal external electrode layers are further provided on both end surfaces of the laminated compact so as to be connected with both ends of the second internal electrode film. The laminated compact may also include a resistance element.

Surge absorber and surge absorber array

A wire wound core has windings which are wound in a single-layer winding fashion around substantially cylindrical body portions of bobbins. A gap is provided between the inner wall of a hole formed in the substantially cylindrical body portion of each bobbin and the outer peripheral surface of a leg portion of a corresponding core member by a rail-shaped rib disposed on the inner wall of the hole. Another gap is provided between the inner surface of an arm portion of the core member and the outer major of a flange portion of the bobbin by a convex spacer disposed on the outer major surface of the core member.

Wire-wound coil

A choke coil is provided having a highly efficient normal-mode inductance component. The choke coil comprises a bobbin, a magnetic core, and a pair of windings. The bobbin has a core portion, and flanges which are respectively provided at both outer ends and at the center of the core portion. The forward end of the central flange, placed near the magnetic core, extends longer than the forward ends of the other flanges located at the ends of the core portion. In one embodiment, the forward end of the central flange is provided with a hole for receiving the magnetic core.

Choke coil

There is provided a choke coil having a sufficient noise eliminating effect against common mode and normal mode noises. The choke coil has two bobbins, a pair of windings wound around the respective bobbins, first and second magnetic cores which are each inserted in cylindrical body portions of the bobbins at one side thereof, and a support member for supporting the cores. The first magnetic core is in the form of the character B and made of a material having lower permeability. The second magnetic core is in the form of the character D and made of a material having higher permeability. A predetermined gap is maintained between the cores by a spacer provided on the top surface of the support member.

Choke coil for eliminating common mode noise and normal mode noise

A choke coil is disclosed which exhibits sufficient capability in suppressing both common-mode noise and normal-mode noise with a small number of parts. A bobbin is formed of a rod and flanges provided for the rod. A pair of windings are reeled around the rod. Further, one side of a hollow-rectangular integral-type magnetic core is inserted into a hole formed in the rod of the bobbin. The heights of the flange of the bobbin are set as L2 in the upward direction, while the heights of the flange of the bobbin are determined as L1 in the downward direction (as illustrated) with L1&gt;L2, i.e., the heights of the flange are varied in the directions along the outer peripheral surfaces of the flange.

Choke coil for suppressing common-mode noise and normal-mode noise

A choke coil exhibits sufficient capability in suppressing both common-mode noise and normal-mode noise while inhibiting an occurrence of magnetic saturation of a magnetic core. A terminal stand is formed of a frame and a magnetic plate. A split-type bobbin has a bobbin member made from a magnetic substance and a bobbin member made from an insulating substance. The bobbin is formed of a rod and three flanges provided for the rod. A pair of windings are reeled around the rod of the bobbin. Further, one side of an integral-type magnetic core formed in a hollow-rectangular shape is inserted into a hole formed in the rod of the bobbin. The magnetic bobbin member is placed outside a region surrounded by a closed magnetic path formed by the magnetic core. The magnetic bobbin member also forms a closed magnetic path together with the magnetic plate of the terminal stand.

A choke call includes a bobbin, a pair of windings wound around the bobbin, and two magnetic cores. The bobbin has a rectangular barrel in which a circular hole is defined. The two magnetic cores are partly inserted into the hole of the barrel. The hole is offset from the central axis of the barrel. A central collar extends perpendicular to and at the central portion of the barrel. Two end collars extend beyond and parallel to opposite ends of the barrel. The thickness of the central collar is approximately two times greater than that of the end collars. The magnetic cores collectively form an opening. Within the opening, the gap between the outer periphery of the central collar and the magnetic cores is greater than that between the outer periphery of the end collars and the magnetic cores. A part of the magnetic cores within the hole has a circular or rectangular cross-section.

A choke coil having a sufficient noise eliminating effect against common mode and normal mode noises. The choke coil has a bobbin, a pair of windings wound around the bobbin, and magnetic cores inserted in a rectilinear body portion of the bobbin. The bobbin is constituted by a main body and a cap each of which incorporates a magnetic core. The upper half of those magnetic cores forms a closed magnetic circuit that extends around one of the windings while the lower half forms a closed magnetic circuit that extends around the winding.

A compliant pin terminal inserted into a through hole, such as a center hole of a feed-through capacitor or a through hole of a circuit substrate having an electrode at the inner periphery thereof, is mounted into the through hole for electrically connecting with the electrode therein. The pin terminal includes slits, by which linear divided portions and expanded elastic contact portions are formed so that when the body is inserted into the through hole of the capacitor the elastic contact portions come into press-contact with the electrode, thereby obtaining electrical connection with the electrode and mechanical locking by means of the elasticity of each elastic contact portion. A lengthwise pulling force acting on the terminal body is borne by the linear divided portions, but does not act on the elastic portions. Accordingly, an interval between the elastic contact portions opposite to each other resists change, thereby effectively preventing the pin terminal from escaping from the through hole.

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Takefu, Japan

Takaaki Ooi