JPH08213248A - Chip inductor - Google Patents

Abstract

PURPOSE: To reduce loosening and slack of a wound coil by winding a coil electric wire of which section is nearly in square shape within a range where the upper surface of an outer-periphery part is nearly at the same surface as the outer-periphery surface upper surface of a both-edge flange part at a core part of which section is in square shape, performing the contact bonding of the both edges to an electrode, increasing the occupation rate of the coil, and reducing a DC resistance surface. CONSTITUTION: A core 11 of a metal oxide is provided with a core part 12 whose section is in square shape and a square-shaped flange part 13 formed at both edges. An electrode 14 consisting of a film-shaped conductor is formed at the bottom surface part and the outer- surface lower part of the both-edge flange part 13. A coil electric wire 16 whose section is nearly in square shape is wound around the core part 12 of the magnetic core 11 within a range so that the outer-periphery surface upper surface of a coil 15 is nearly at the same surface as outer-periphery surface upper surface of the both-edge flange part 13 at the core part 12 of the magnetic core 11 and both edges are subjected to contact bonding for fixing. An impregnation adhesive 17 is applied to the upper-surface part of the coil electric wire 16 and heat resistance coldproofing film 20 is joined while covering the upper-surface part of the flange part 13, thus reducing the loosening and slack of the coil electric wire 16 and improving occupation rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone, a video camera, a transmitting / receiving circuit of a computer, a noise filter, an amplifying circuit, a chip inductor used for current detection and the like.

[0002]

2. Description of the Related Art In a conventional chip inductor of this type, as shown in FIG. 4, for example, projecting portions 2 are provided on both lower ends of a magnetic core 1, and Ag is provided on the bottom surface of the projecting portion 2 and on the outer end portions of both ends. / Pd
An electrode 3 composed of, for example, a coil wire 4 having a circular cross section is wound between the protrusions 2 of the magnetic core 1 to form a coil 5,
A structure in which both ends of the coil electric wire 4 are connected to the both electrodes 3 to form a chip inductor body 6, and a top surface of the chip inductor body 6 is formed into a planar shape by a resin-coated covering portion 7. Was taken.

[0003]

In the above-mentioned conventional chip inductor, since the upper surface of the chip inductor body 6 is covered with the resin-coated covering portion 7 to form a flat surface, the chip inductor body 6 and the covering portion 7 are covered with each other. Positional deviation easily occurs and dimensional accuracy is not good. Further, since the coil electric wire 4 has a circular cross section, there is a problem that loosening or misalignment easily occurs, and the space factor of the coil is small, so that the DC resistance value (RDC)
Has the problem of being large.

The present invention has been made in view of the above problems, and can increase the space factor of the coil, reduce the RDC, easily form the upper surface into a flat shape, and reduce the winding looseness and looseness of the coil in an aligned winding. It provides a chip inductor that is easy to implement and has excellent mountability and frequency characteristics.

[0005]

A chip inductor according to a first aspect of the present invention is a metal oxide having a winding core portion having a rectangular cross section and square flange portions formed at both ends of the winding core portion. A magnetic core formed by molding, an electrode composed of a film conductor formed on the bottom surface of both ends of the flange of the magnetic core and lower portions of the outer surfaces of both ends of the magnetic core, and the outer peripheral surface of the winding core portion has an outer peripheral surface upper surface of the both end flange portions. A coil wire having a substantially quadrangular cross-section wound in a range up to substantially the same surface and crimp-connected to both ends of the electrode, and an upper surface of the coil wire forming a coil wound around the core of the magnetic core. Portion of the coil wire wound around the winding core portion of the magnetic core and the upper surface portion of the flange portion are joined by the adhesive to form a substantially quadrangular shape And a heat and cold resistant film.

A chip inductor according to a second aspect of the present invention is the chip inductor according to the first aspect, wherein the heat and cold resistant film is formed of an oxide magnetic material.

[0007]

According to the chip inductor of the invention described in claim 1, the coil wire having a substantially rectangular cross section is provided on the winding core of the magnetic core having a quadrangular cross section, and the upper surface of the outer peripheral portion is substantially flush with the upper surfaces of the outer peripheral surfaces of the flanges at both ends. Since the coil wire is wound in the range up to, the looseness and looseness of the coil wire can be reduced, aligned winding can be performed, the space factor of the coil can be improved, and the direct current resistance value (RDC) can be reduced.
Also, the impregnating adhesive applied to the upper surface of the coil wire wound around the winding core of the magnetic core to form a coil is joined across the upper surface of the coil wire and the upper surface of the flange. The upper surface of the chip inductor can be easily planarized with the substantially rectangular heat-resistant and cold-resistant film, and a chip inductor having excellent frequency characteristics and mountability can be obtained.

In the chip inductor according to the second aspect of the present invention, by forming the heat-resistant and cold-resistant film of the oxide magnetic material, a simple shield can be easily formed and the inductance range can be expanded.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of an embodiment of the present invention will be described with reference to FIGS.

Reference numeral 11 denotes a magnetic core molded of a metal oxide, and the magnetic core 11 is made of, for example, ferrite or alumina having a magnetic permeability μ = 1 (main component is Al ₂ O ₃ ) having a rectangular cross section. It has a core portion 12 and square flange portions 13 formed at both ends of the winding core portion 12, and is molded into a substantially H-shaped form.

A silver-palladium-based material, or a silver-palladium-based material in which nickel is plated on silver on the bottom surface of the flanges 13 on both ends of the magnetic core 11 and lower portions on the outer surfaces of both ends of the magnetic core 11, is further plated. Each of the electrodes 14 is made of a film conductor such as nickel plated on top of which solder (Sn-Pb type) is plated, or copper is directly plated with solder (Sn-Pb type). Has been formed.

A coil electric wire 16 having a substantially rectangular cross section is wound around the winding core portion 12 of the magnetic core 11 so as to form a coil 15. It is wound in the range until it becomes substantially flush with the upper surface of the outer peripheral surface. Then, both ends of the coil electric wire 16 are connected to the electrode 14 by pressure bonding.

Further, a coil 15 is attached to the winding core portion 12 of the magnetic core 11.
Epoxy resin-based, acrylic resin-based, on the upper surface of the coil electric wire 16 of the chip inductor body 18 formed by winding
An impregnating adhesive 17 such as polyurethane is applied by a dispenser or a roller.

Then, a substantially rectangular polyimide film, a PPS film, a polyester film straddling the upper surface of the coil electric wire 16 and the upper surface of the flange portion 13 wound around the winding core portion 12 of the magnetic core 11. Heat and cold resistant film such as 20
And the chip inductor main body 18
The upper surface portion is formed into a flat shape.

Next, the operation of this embodiment will be described.

A coil wire having a quadrangular cross section in which one end is crimp-connected to a winding core portion 12 having a quadrangular cross section of a magnetic core 11
16 is wound in a line so that at least the upper surface of the outer peripheral portion of the coil electric wire 16 becomes substantially flush with the upper surface of the outer peripheral surface of the flange portions 13 on both ends, and the other end of the coil electric wire 16 is crimped to the other electrode. Then, the coil 15 is formed. In this state, the winding core portion 12 has a substantially quadrangular cross section, and the coil electric wire 16 has a quadrangular cross section. Therefore, loosening and loosening of the coil electric wire 16 is reduced, alignment winding can be easily performed, and a space factor of the coil 15 And RDC can be reduced. Also, the core of the magnetic core 11
A heat-resistant and cold-resistant film having a substantially rectangular shape extending over the upper surface of the coil electric wire 16 and the upper surface of the flange portion 13 with an impregnating adhesive 17 on the upper surface of the coil electric wire 16 wound around 12 to form the coil 15. Chip inductor body 18 by joining 20
It is possible to easily make the upper surface of the substrate flat and obtain a chip inductor with low cost and excellent mountability.

Further, by forming the heat-resistant and cold-resistant film 20 from an oxide magnetic material such as ferrite or a thermoplastic resin filled with ferrite, simple shielding can be facilitated and the inductance range can be expanded. Becomes

[0018]

According to the invention as set forth in claim 1, the loosening and loosening of the coil electric wire is reduced, the aligned winding can be easily performed, the space factor of the coil can be improved, and the DC resistance value can be reduced. Further, the heat-resistant and cold-resistant film can easily make the upper surface of the chip inductor into a flat surface, and a chip inductor having excellent frequency characteristics and mountability can be obtained.

According to the second aspect of the present invention, by forming the heat and cold resistant film with an oxide magnetic material, a simple shield can be easily made and the inductance range can be expanded.

[Brief description of drawings]

FIG. 1 is a perspective view of a chip inductor showing an embodiment of the present invention.

FIG. 2 is a perspective view from the bottom side of the above chip inductor.

FIG. 3 is a sectional view of the same chip inductor.

FIG. 4 is a front view of a conventional chip inductor.

[Explanation of symbols]

 11 magnetic core 12 winding core 13 flange 14 electrode 15 coil 16 coil wire 17 impregnating adhesive 18 chip inductor body 20 heat and cold resistant film

Claims (2)

[Claims] 1. A magnetic core formed of a metal oxide having a winding core portion having a rectangular cross section and square flange portions formed at both ends of the winding core portion, and flange portions at both ends of the magnetic core. An electrode made of a film-shaped conductor formed on the bottom surface portion and lower portions on both outer surfaces of the both ends, and the winding core portion is wound in a range until the outer peripheral surface upper surface is substantially flush with the outer peripheral surface upper surface of the both-end flange portion. A coil wire having a substantially rectangular cross-section with both ends crimped and connected, an impregnating adhesive applied to the upper surface of the coil wire wound around the winding core of the magnetic core to form a coil, and the winding of the magnetic core. A chip inductor comprising a substantially quadrangular heat-resistant and cold-resistant film which is joined by the adhesive across the upper surface of the coil wire wound around the core and the upper surface of the flange. 2. The chip inductor according to claim 1, wherein the heat and cold resistant film is formed of an oxide magnetic material.