JP3530604B2 - Chip inductor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip inductor provided with a pair of electrode pieces to which both ends of a coil are connected at both ends of a core on which the coil is wound. 2. Description of the Related Art Conventionally, as this type of chip inductor, for example, a configuration described in Japanese Patent Application Laid-Open No. 2-50404 has been known. In the chip inductor described in Japanese Patent Application Laid-Open No. 2-50404, a pair of leads is provided in which both ends of a coil wound around a core portion of a drum core are axially projected from both end surfaces of the drum core. Each coil is connected to a terminal, and the coil is covered with a protective layer. Furthermore, the lead terminals are engaged with the engaging portions provided at the upper end at positions spaced apart from the both end surfaces of the drum core, with the rising portions of the pair of electrode pieces rising toward the both end surfaces of the drum core. They are electrically and mechanically connected, and are molded so that the drum-shaped core on which the coil is wound, the lead terminals, and the rising portions of the electrode pieces are integrally covered with the molded body. [0004] However, in the above-described chip inductor disclosed in Japanese Patent Application Laid-Open No. 2-50404, since the cross section of the drum core is circular, the winding becomes loose when the coil is wound. There is a possibility that the dispersion will occur, and a predetermined inductance cannot be obtained. Further, since the rising portion of the electrode piece faces the end face of the drum type core, there is a problem that the magnetic flux generated when the coil is energized intersects with the rising portion, thereby lowering the Q value. The present invention has been made in view of the above problems, and has as its object to provide a chip inductor capable of stably obtaining predetermined characteristics. According to a first aspect of the present invention, there is provided a chip inductor, wherein the coil is wound around a coil.
Core portion formed in a quadrangular prism and the coil is provided on both axial ends being wound and the winding core of the winding core
Protrude outward on a pair of opposite sides of
Core having a rectangular pillar-shaped protruding edge portion, and a core portion of the core
Said coil provided on one side surface of the flange portion to be flush with
A pair of conductive portions, both ends of which are respectively connected, and the coil
Are connected to a pair of conductive parts connected respectively.
A pair of electrode pieces and the coil connected to the conductive portion
Outer periphery of the coil on the side where the lead wire of these conductors is located
And a protective layer of a synthetic resin provided on a surface, a portion of the core and the pair of electrode pieces which the coil is wound is to comprise a mold member embedding integrally ash. [0008] [action] chip inductor according to claim 1 is four to form a core portion of the core of winding a coil in quadrangular prism shape
Projecting outward on a pair of opposing sides of the prismatic core
Since the core was formed by providing a protruding edge in the shape of a square pillar,
The coil wound around the pillar-shaped core has no looseness or looseness , and the lead wire from the coil connected to the conductive part is not drawn.
The synthetic resin protective layer provided on the side where
In addition, it is possible to prevent the coil from being loosened or dislodged, and to obtain predetermined characteristics stably. In addition, the surface area of the core
The ratio decreases and the stress generated during curing of the mold
Reduces the strain on the core, preventing the permeability from decreasing.
Predetermined characteristics can be obtained stably and easily. In addition , the core
Both ends of the coil are connected to one side of the protruding edge
And a pair of conductive members to which a pair of electrode pieces are respectively connected.
Part, so that when the coil is energized,
As a result, the amount of magnetic flux is reduced, and a decrease in the Q value is prevented. An embodiment of a chip inductor according to the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a chip inductor. The chip inductor 1 has a core 2 made of a magnetic material such as ferrite. The core 2 includes a quadrangular prismatic core 3 having a rectangular cross section, and a quadrangular prism-shaped protruding edge 4 that protrudes in a flange shape substantially perpendicularly from longitudinally opposite sides at both axial ends of the core 3. From plane H
It is formed into a square shape in the shape of a letter. Also, the protruding edge 4 of the core 2
A conductive portion 5 formed of a conductive material is provided on a side surface on the same plane as the core portion 3. In the chip inductor 1, a conductive wire 7 such as a polyurethane-coated electric wire is wound around a core portion 3 of a core 2, and both ends are electrically and mechanically connected to conductive portions 5 and 5, respectively. Is wound. Further, on the outer peripheral surface of the coil 8, on the side where the lead wires 7 a, 7 a of the conductor 7 from the coil 8 connected to the conductive portion 5 are located, a polybutadiene such as a polybutadiene for preventing the coil 8 from being loosened or loosened. A protective layer 9 made of a synthetic resin is provided. The core 2 is electrically and mechanically connected to the conductive portion 5 at one end of an elongated metal plate-shaped electrode piece 10. The chip inductor 1 includes a coil 8
The core 2 on which is wound and a part of the pair of electrode pieces 10, 10 are integrally molded with a molding resin to form a molded body.
11 and embedded along the outer peripheral surface of the mold body 11.
The electrodes 10 and 10 are bent in the same direction to form electrodes, and are formed in a chip shape. The electrode piece 10 is not limited to a mere metal piece, and may be one having a solder layer provided on the outer surface in advance, or a solder layer provided on the outer surface after bending. Next, the manufacturing process of the above embodiment will be described with reference to the drawings. First, as shown in FIG. 3, a substantially H-shaped flat core 2 having projections 4 at both ends in the axial direction of a winding core 3 is formed in advance from a magnetic material such as ferrite. FIG. 4 shows a side surface of the protruding edge portion 4 of the core 2 which is flush with the core 3.
As shown in (1), a pair of conductive portions 5 are provided by vapor deposition, sputtering, thick film printing, metal foil bonding, or the like. Then, one end of a conductive wire 7 such as a polyurethane-coated electric wire is electrically and mechanically connected to one conductive portion 5 of the core 2 by thermocompression bonding such as pulse heating, and the conductive wire 7 is wound around the core 2. The conductor 3 is wound around the core 3 a predetermined number of times.
Is electrically and mechanically connected to the other conductive portion 5 in the same manner, and as shown in FIG.
Is wound. Next, the core 2 on which the coil 8 is wound is connected to the core 2 shown in FIG.
As shown in FIG. 5, a pair of conductive portions 5, 5 to which the lead wires 7a, 7a are connected are mounted on the tips of the metal pieces 13a, 13a between the metal pieces 13a, 13a protruding opposite to the strip-shaped metal frame 13. The core 2 is placed so as to be placed, and the conductive portion 5 and the metal piece 13a are respectively connected by welding, thermocompression bonding, or the like. And
As shown in FIG. 7, a protective layer 9 made of a synthetic resin such as polybutadiene is provided on the surface of the coil 8 to which the metal piece 13a is attached. Thereafter, as shown in FIG. 8, the core 2 around which the coil 8 is wound and the tip portions of the pair of metal pieces 13a, 13a are integrally molded into a substantially rectangular parallelepiped with a molding resin, and the cured mold is formed. The outer peripheral surface of the body 11 is appropriately marked. The metal pieces 13a, 13a of the metal frame 13
a is cut into a metal piece 13a to form an electrode piece 10, and a pair of electrode pieces 10, 10 projecting from the molded body 11 are bent toward the protective layer 9 along the outer peripheral surface of the molded body 11. The electrodes are formed with their tips facing each other, and the chip inductor 1
To form Next, the operation of the above embodiment will be described. The coil 8 of the chip inductor 1 manufactured in the above embodiment was energized, and the frequency characteristics of inductance and Q value were measured. Further, as a comparative example, a chip inductor having a drum-shaped core formed so as to have the same outer diameter was used. The results are shown in FIG. 9 and FIG.
0 is shown. From the results of the frequency characteristics shown in FIG. 9, in the case of this embodiment, a higher Q value can be obtained than in the case of using the conventional drum core, and the rate of change of the inductance with respect to the change of the frequency is small. It can be seen that stable characteristics can be obtained. Further, from the results of the DC superimposition characteristics shown in FIG. 10, it can be seen that in the present embodiment, the decrease in inductance due to the increase in the DC superposition current is smaller than that of the conventional device, and the current capacity can be increased. It is known that when the conductor 7 is wound around the core portion 3 of the core 2, a predetermined inductance cannot be obtained if the conductor 7 is unbalancedly wound. When a conventional core is wound around a cylindrical drum-shaped core, the conductor may not be caught between the conductor and the outer peripheral surface of the core, and the conductor may be loosened or loosened. There, although predetermined inductance by loosening the winding or the loosened is not obtained, the core 2 of the present embodiment, since the core portion 3 is square pillar shape, such that the conductive wire 7 is caught by the corners of the core part 3 since the wound around, be uniformly wound without winding slack or loose, predetermined inductance is obtained line-to-line capacitance is stable. Further, in the present embodiment, the protective layer 9 is provided on a part of the coil 8 to securely prevent the coil 8 from being loosened or loosened at the time of molding, so that a predetermined inductance can be obtained. On the other hand, when the chip inductor 1 is formed so that the outer dimensions are within a predetermined range, the core 2 may be formed in a quadrangular prism shape to obtain the widest cross-sectional area. For this reason, the core part 3 is formed in a quadrangular prism shape as in this embodiment,
At both ends in the axial direction of the core part 3, a quadrangular prism-shaped protruding edge part 4 is formed so as to protrude from a longitudinally opposed side substantially in the form of a flange so that the core 2 is formed into a substantially H-shaped square plane. As a result, a core 2 having a wide cross-sectional area can be obtained, and a chip inductor 1 having a high Q value can be obtained. Further, since the core 2 of this embodiment has a larger volume than that of the conventional drum core, the magnetic characteristics are improved. On the other hand, when the core 2 is molded with a mold resin and covered with the mold body 11, an internal stress is generated by the curing and shrinkage of the mold resin, and the internal stress acts on the core 2. Since the chip inductor 1 of the present embodiment is molded in a rectangular parallelepiped shape so that the mounting surface on which the electrodes are formed for surface mounting is flat, the conventional drum-type core is formed on the peripheral surface of the core. While the thickness is not uniform and the stress load is concentrated on the thin portion of the core and the magnetic permeability is reduced, the core 2 of the present embodiment is prismatic, so the thickness of the mold body 11 is small. Is formed on the peripheral surface of the core 2 so as to have a substantially uniform thickness. Therefore, the internal stress generated at the time of curing shrinkage of the mold body 11 is substantially uniformly applied to the core 2, and in this embodiment, the internal stress is not locally concentrated, the magnetic permeability is less reduced, and the stable inductance is reduced. Is obtained. In this embodiment, a conductive portion 5 is provided on the side surface of the protruding edge portion 4 of the core 2 which is flush with the core portion 3, and the conductive portion 5 is wound around the core portion 3. Since the lead wire 7a of the conducting wire 7 of the coil 8 and one end of the electrode piece 10 are electrically and mechanically connected in parallel to the magnetic flux direction, the magnetic flux generated when the coil 8 is energized intersects the electrode piece 10. The amount is reduced, and a decrease in the Q value can be prevented. According to the chip inductor according to claim 1, wherein, according to the present invention, to form the winding core portion of the core of winding a coil in quadrangular prism shape
And a pair of opposing sides of the square core
The core is formed by protruding toward
Therefore, the coil wound around the square pillar-shaped core has no looseness or looseness .
Of the synthetic resin provided on the side where the lead wire of
The protective layer can reliably prevent coil loosening and loosening,
Predetermined characteristics can be obtained stably , and the core body
And the stress generated during curing of the mold
Reduced core strain and reduced magnetic permeability
And it is possible to obtain predetermined characteristics stably and easily.
And one end of the coil on one side of the protruding edge of the core.
Connected and a pair of electrode pieces
A pair of conductive parts connected in parallel to the magnetic flux
The amount of magnetic flux that intersects the electrode piece when current is
The value can be prevented from lowering.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing one embodiment of a chip inductor of the present invention. FIG. 2 is a side view of the same. FIG. 3 is a perspective view showing a core in a manufacturing process of the same chip inductor. FIG. 4 is a perspective view showing a core after a conductive portion is formed in a manufacturing process of the chip inductor. FIG. 5 is a perspective view showing a state in which a coil is wound in a manufacturing process of the chip inductor. FIG. 6 is a perspective view showing a state in which metal pieces are connected in a manufacturing process of the same chip inductor. FIG. 7 is a perspective view showing a state in which a protective layer is provided in a manufacturing process of the chip inductor. FIG. 8 is a perspective view showing a state of molding in a manufacturing process of the same chip inductor. FIG. 9 is a graph showing frequency characteristics of the same chip inductor. FIG. 10 is a graph showing a DC superposition characteristic of the same chip inductor. [Description of Signs] 1 chip inductor 2 core 3 core part 4 protruding edge part 5 conductive part 7 conductive wire 7a lead wire 8 coil 9 protective layer 10 of synthetic resin 10 electrode piece 11 molded body

Claims (1)

(57) [Claim 1] A coil, a quadrangular pillar-shaped core portion in which the coil is wound in the middle, and an axial direction of the core portion where the coil is wound. It is provided at both ends and is outside the pair of opposite sides of the core portion.
A core provided with a quadrangular prism- shaped protruding edge protruding in a flange shape toward one side, and provided on one side surface of the protruding edge which is flush with the core of the core.
And a pair of conductive members to which both ends of the coil are respectively connected.
Part and a pair of conductive parts each connected to both ends of the coil.
Lead wire extraction from a pair of electrode pieces to be connected and the coil connected to the conductive part
A synthetic tree provided on the outer peripheral surface of the coil on the side where the tie line is located
Chip inductor, wherein the protective layer of fat, and a kite comprising a mold body embedded integrally a part of the core and the pair of electrode pieces which the coil is wound.