JP2966624B2 - Chip inductor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip inductor having good inductor characteristics and having no displacement of terminals during manufacturing, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As electronic devices become smaller and lighter, there is a demand for a chip of an inductor which can be used by an automatic insertion machine together with a resistor or a capacitor. FIG. 7 is an explanatory view of a lead frame for manufacturing an inductor in a conventional example. FIG. 8 is a view for explaining a state in which an inductor is mounted on a lead frame in a conventional example. FIG. 9 is a partially cutaway view of an inductor body in a conventional example. A conventional example of a chip inductor will be described with reference to FIGS. 7 to 9, first, a lead member 101 is formed by punching out a strip member made of a metal plate. That is, the lead frame 101 is a parallel portion including a continuous portion 102 for preventing the strip members from being separated when punched, and a lead wire mounting portion 103 on which lead wires to be described later are mounted and a terminal portion 104. And a cut-and-raised portion 105.

On the other hand, the chip-shaped inductor element includes a drum core 111 formed of a ferrite core and flanges provided at both ends thereof, a coil 112 formed by winding a conductor wire whose surface is insulated and coated on the ferrite core. A pair of lead wires 1 implanted on the axis of the flange with an adhesive
13. Then, both ends of the coil 112 are connected to the lead wire 113 by, for example, soldering after being entangled with the lead wire 113. Thereafter, the chip-shaped inductor body is connected to the lead frame 101.
The lead frame 1 is placed on the lead
01 and the lead wire 113 are connected by soldering or spot welding. Then, the entire chip-shaped inductor body is molded with an insulating resin exterior body 122 except for the terminal portion 104 of the lead frame 101. Further, the terminal portions 104 protruding from the mold are bent along the mold to become the external connection terminals 121 of the chip inductor. Regarding the above-mentioned chip-shaped inductor, for example,
No. 50404 has a detailed description.

Another conventional example will be described with reference to FIGS. FIG. 10 is a diagram for explaining a chip-shaped inductor having a terminal portion provided with a notch. FIG.
1 is an external view of FIG. 10 and 11, a coil 132 is wound around the drum core 131. A notch 134 is provided in the terminal 133 connected to a lead frame (not shown). The drum core 131 is placed so that a part of the drum core 131 falls into the cutout portion 134. Then, a coil terminal 132 'formed at both ends of the coil 132
Are soldered to the terminal portion 133, for example. The chip-shaped inductor element body thus formed is molded with an insulating resin exterior body 136 while leaving a part of the terminal portion. The terminal portion exposed from the mold is bent inward along the exterior body 136 to form the external connection terminal 1.
Mold 35 and 135 '.

FIG. 12 is a view for explaining a modification of the conventional example shown in FIG. In FIGS. 10 and 12, the same parts are denoted by the same reference numerals. 12 differs from the chip-shaped inductor of FIG.
3 is that both ends of the notch 134 are cut and raised. The cut-and-raised portion 151 can stably support the drum core 131 together with the cutout portion 134. Note that the chip-shaped inductors shown in FIGS.
No. 108 has a detailed description.

FIG. 13 is a diagram for explaining another conventional example. In FIG. 13, the chip-shaped inductor element is cut and raised in parallel from a drum core 161, a coil (not shown), a lead wire 162 implanted on the axis of a flange of the drum core 161, and a lead frame (not shown). And a lead wire mounting portion 163 on which the lead wire 162 is further bent and mounted, and a terminal 165 having a base portion of the cut-and-raised portion 164 cut and raised in parallel from the lead frame as a terminal. Be composed. The terminal of the coil not shown is tied to the lead wire 162. Then, lead 162
Is soldered or welded to the lead wire mounting portion 163. The chip-shaped inductor element body thus manufactured is molded by the exterior body 166 except for the terminal 165. Then, the terminal 165 is bent along the surface of the exterior body 166 to form a chip inductor as shown in FIG. The chip-shaped inductor shown in FIG. 13 is disclosed in, for example, Japanese Utility Model Laid-Open No. 63-191612.

[0007]

In the chip-shaped inductor shown in FIGS. 7 to 9, the terminal portion 104 is provided not only close to the main surface of the flange but also in parallel with the flange. Therefore, the magnetic flux generated from the inductor forms an open magnetic path after passing through the terminal portion 104 and is consumed as an eddy current on the conductor surface of the terminal portion 104. Therefore, the chip-shaped inductor has a problem that its quality factor and inductor value are reduced. Further, in the above conventional example, since the lead wire mounting portion 103 on which the lead wire 113 is mounted has only a thickness of the plate-shaped member, there is a problem that it is difficult to solder or spot weld the two. Further, when the lead wire 113 is placed on the lead wire placing portion 103 by the automatic manufacturing machine, the lead wire 113 is not always positioned symmetrically. Even if the lead wire 113 is arranged at a correct position, the position of the lead wire 113 is shifted when given some vibration. For this reason, there is a problem that the characteristics of the chip-shaped inductor vary.

In order to solve the above problem, a terminal portion as shown in FIG. 6 has been developed. FIG. 6 is a diagram showing only one terminal portion in the conventional example. In FIG.
A lead wire mounting portion 62 for mounting the lead wire 113,
An opening 63 having a width smaller than that of the lead wire placement portion 62 and a vertical split groove 64 communicating with the lead wire placement portion 62 are provided. Then, the lead wire 113 is mounted on the lead wire mounting portion 62 of the terminal portion 61. At this time, lead wire 1
13 is an opening 63 of the lead wire mounting portion 62 narrower than the width thereof.
Is mounted on the lead wire mounting portion 62 while the width of the lead wire is widened by the vertical split groove 64. Therefore, even if the diameter of the lead wire 113 is slightly different, the lead wire 113 is mounted on the lead wire mounting portion 62 and is held by the spring property of the vertical split groove 64. However, the lead wire mounting portion 62 as described above has a narrow expansion and contraction width due to the spring property, and it is difficult to provide a moderate spring property for holding the lead wire.

In order to reduce the eddy current generated in the terminal portion 133, a chip inductor shown in FIGS. 10 to 12 has been developed. In this chip-shaped inductor, as described above, without providing a lead wire on the flange of the drum core 131, a pair of flat plates protruding from the lead frame is provided with a cutout portion 134 having a width slightly smaller than the diameter of the flange. Is mounted on the flange. Therefore, since the terminal portion 133 is not parallel to the flange portion of the drum core 131, an eddy current is generated
Only the portion corresponding to the end area of the terminal portion 133 is provided. Therefore, the above-mentioned chip-shaped inductor can obtain an inductor larger than those shown in FIGS. However, in the case of the drum core 131 or the cylindrical core having no lead wire, a conventional winding machine for manufacturing a coil by fixing the lead wire portion cannot be used. Further, when winding the coil, the flange portion of the drum core 131 must be supported by a chuck or the like. For this reason, since the diameter of the flange is different for each type of inductor, the structure of the chuck is complicated, and it is difficult to center the coil when winding it. In addition, the notch portion 134 formed in the terminal portion 133
Has a problem that the notch width must be changed for each type of chip-shaped inductor. In addition, coil 1
The 32 terminals 132 ′ required another processing step different from the coil winding, in which soldering was performed on the terminal portion 133.

In the conventional example shown in FIG. 13, a lead wire mounting plane formed in a plane parallel to the lead wire 113 is used to simplify the connection between the lead wire mounting portion 103 and the lead wire 113 shown in FIGS. The mounting part 163 is provided. However, in connection with the connection between the lead wire 113 and the lead wire mounting portion 163, the above problem has been solved, but the problem of reduction in the inductor due to eddy current has not been solved yet.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. In a chip-shaped inductor in which a lead wire is implanted in a flange of a drum core, the chip-shaped inductor has improved inductor characteristics and does not displace a terminal portion. An object of the present invention is to provide an inductor and a method for manufacturing the inductor.

[0012]

Means for Solving the Problems (First Invention) To achieve the above object, a chip inductor according to the present invention comprises a ferrite core (22 in FIG. 3) and flanges (2 in FIG. 3) at both ends.
3), a pair of lead wires (24 in FIG. 3) implanted on the axis of the flange (23), and a ferrite core (22) of the drum core (21). And a coil having both ends of the winding wound around the lead wire (24) and connected thereto, and a lead wire (2).
4) Lead wire mounting hole for mounting (6 in FIGS. 2 and 3)
And an opening (5 in FIGS. 2 and 3) narrower than the lead wire mounting hole (6), and an asymmetrical split groove formed from the lead wire mounting hole (6) (FIGS. 2 and 3). 7), and an insulating resin exterior body in which the drum core (21), the lead wire (24), the coil, and a part of the terminal portion (10) are embedded. (FIG. 5
41).

(Second Invention) In the method of manufacturing a chip-shaped inductor according to the present invention, a center slit (4 in FIG. 1) cut along a center line of a conductor strip (1 in FIG. 1) and the center thereof are formed. An opening (5 in FIG. 1) provided at the midpoint of the slit (4) and smaller than the diameter of the lead, and a lead wire mounting hole (FIG. 1) communicating with the opening (5) and mounting the lead wire (24). 6) and an opening (5) narrower than the lead wire mounting hole (6) and a left-right asymmetric split groove (7 in FIG. 1) communicating with the lead wire mounting hole (6). 2), a first step formed by punching a conductor strip symmetrically with respect to a center point, and a terminal portion (1 in FIG. 2) standing in the opposite direction from the center slit (4).
0), a third step of implanting a lead wire (24) around the axis of a drum core (21) having flanges (23) at both ends of a ferrite core (22), 21) winding a winding around to form a coil, and tying both ends of the coil to the lead wire (24), and the lead wire (24) obtained in the process.
A fifth step of placing both ends of the lead wire in the lead wire mounting hole (6 in FIG. 1) by widening the opening (5), and the lead wire (24)
A sixth step of connecting the drum core (21), the lead wire (24), the coil, and a part of the terminal to form an exterior body (41); The terminal portion (1) exposed from the exterior body (41).
An eighth step of separating the terminal portion (10) from the conductor strip (1) along the outer package (41) to form the external connection terminals (31, 32).
And a process.

[0014]

[Operation] (First invention) Flanges are formed at both ends of the drum core with respect to the axis. Lead wires are implanted on the center shafts at both ends of the flange by, for example, an adhesive. The coil is wound around the core of the drum core, and both ends of the coil are wrapped around a lead wire, and then that portion is soldered. On the other hand, a formed lead wire mounting hole and an opening having a smaller diameter than the lead wire mounting hole are formed in the terminal portion cut and raised from the lead frame. Then, the lead wire is clamped in the lead wire placement hole so as to push the opening. The resiliency for holding the lead wire is generated by an asymmetrical split groove communicating with the lead wire mounting hole. That is, the terminal portion connected to the lead wire mounting hole is formed by the split groove.
Since one of the widths is narrow, only one of them moves to open. Thereafter, the lead wire and the lead wire mounting hole are connected by, for example, spot welding. Next, an exterior body is applied with an insulating resin except for a part of the terminal portion.
The terminal portion exposed from the outer package is separated from the conductor strip, and then bent along the outer package to form an external connection terminal of the chip inductor. In the chip-shaped inductor having such a configuration, after the lead wire is opened and enters the lead wire placement hole, it is sandwiched from both sides. Therefore,
The lead wire can be accurately placed at a position remote from the flange of the drum core. Further, since the lead wire is arranged apart from the drum core, the magnetic flux passing through the terminal portion can be reduced. Furthermore, since the lead wire mounting hole can provide spring properties, even if vibration occurs during temporary fixing of the lead wire and the lead wire mounting hole, the lead wire may jump out of the terminal portion or may have a position. No deviation occurs. Therefore, the chip-shaped inductor of the present invention has a large inductance, and the lead wire is correctly placed in the lead wire placement hole.

(Second invention) The conductor strip has a center slit along its center line, a lead wire mounting hole having a narrow opening provided symmetrically with respect to a center point of the center slit, and An asymmetrical split groove communicating with the lead wire mounting hole is formed by punching a mold. Thereafter, the portions to be the terminal portions are erected on both sides from the center slit provided on the center line of the conductor strip. On the other hand, a lead wire is implanted on the axis of a flange provided at both ends of a drum core made of a ferrite core. A coil is wound around the axis of the drum core, and both ends thereof are entangled with the lead wire. The lead wire of the drum core around which the coil is wound is inserted into the lead wire mounting hole while expanding the opening. Thereafter, the lead wire is sandwiched in the lead wire mounting hole by the spring property of the split groove. Next, the lead wire and the lead wire placement hole are connected by spot welding. Then, the drum core, the lead wire, the coil, and a part of the terminal portion are provided with an exterior body by molding. The terminal portion exposed from the outer package is separated from the lead frame and then bent along the outer package to form an external connection terminal of the chip inductor. The chip-shaped inductor manufactured as described above is accurately arranged with the terminal portions parallel to the flange of the drum core separated from each other, so that the magnetic flux is hardly reduced.

[0016]

FIG. 1 is a view for explaining a lead frame for producing a chip inductor according to an embodiment of the present invention. In FIG. 1, a lead frame 1 made of a metal plate strip member includes a continuous portion 2 connecting the upper and lower portions of the strip member (in FIG. 1), a space portion 3 for keeping a predetermined distance between the terminal portions, and the space. A center slit 4 formed in the center line of the strip member in the direction of travel of the strip member, a lead wire mounting hole 6 having an opening 5 formed symmetrically from the center of the center slit 4, and the lead wire A split groove 7 communicating with the mounting hole 6 and formed asymmetrically in the left-right direction is formed by, for example, punching a mold. The width of the opening 5 is slightly smaller than the diameter of the lead wire. Further, the opening 5 acts so as to have a spring property by the split groove 7.

FIG. 2 is an explanatory view when a terminal portion is formed from a lead frame according to an embodiment of the present invention. In FIG. 2, first, pressing is performed from the center slit 4 in opposite directions, for example, by a mold. That is, as shown in FIG. 2, the terminal portion 10 stands up. Thereafter, the base of the terminal portion 10 is erected to form the terminal portion 10 shown in FIG.

FIG. 3 is an explanatory view when a chip-shaped inductor according to one embodiment of the present invention is mounted on a terminal portion.
In FIG. 3, a chip-shaped inductor element comprises a magnetic core 22 made of ferrite and flanges 23 and 23 'at both ends thereof.
A lead 24 implanted on the axis of the flange 23, 23 ′ of the drum core 21, a coil (not shown) wound around a magnetic core 22 of the drum core 21, And a terminal of a coil (not shown) connected to the wire 24. Then, the lead wire 24 and the coil terminal entangled with the lead wire 24 are connected by, for example, soldering. The lead wire 24 of such a chip-shaped inductor element body
Are pinched by the lead wire mounting holes 6 of the terminal portion 10 shown in FIG.

FIG. 4 is an enlarged view of a terminal portion according to the present invention. 4, the terminal section 10 will be described in more detail. The lead wire mounting hole 6 formed in the terminal portion 10 has an opening 5 at an upper portion thereof. The opening 5 is made slightly smaller than the diameter of the lead wire. A split groove 7 communicates with the lead wire mounting hole 6 in a left-right asymmetric manner. Therefore, when the lead wire 24 is pushed into the opening 5 and inserted into the lead wire placement hole 6, the terminal portion 10 is easily rotated in the direction of the arrow shown in FIG. . However, the terminal portion 10 does not rotate in the direction opposite to the arrow shown in FIG.
That is, since the 11 narrow portions were provided, the resiliency of the lead wire mounting hole 6 could be improved.

FIG. 5 is a perspective view of a chip inductor according to an embodiment of the present invention. In FIG. 5, after the lead wire 24 of the chip-shaped inductor body is placed in the lead wire placement hole 6, they are connected by spot welding. Thereafter, in a state where the lead frame 1 is connected, a drum core 21 around which a coil (not shown) is wound, a lead wire 24,
The exterior body 41 is formed by molding a part of the terminal portion 10. Next, the terminal portions 10 protruding from the exterior body 41
After being separated from the lead frame 1, it is bent outward along the exterior body 6 to form a bottom terminal portion 31 and a side terminal portion 32. Such a chip inductor is
The bottom terminal portion 31 is soldered to a wiring pattern of a circuit board (not shown). During this soldering, the solder flows from the bottom terminal portion 31 to the side end portion 32. Therefore, the solder that has wrapped around can further increase the mounting strength and be visible from the side, so that the soldering can be confirmed. The winding portion in FIG. 2 is mounted in the lead wire mounting hole 6 of the lead frame 1 shown in FIG. 1 by, for example, an automatic machine.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments. And
Various design changes can be made without departing from the invention as set forth in the appended claims. For example, the shape of the slit or the lead wire mounting hole with respect to the lead frame, and the angle of the split groove, as long as there is no generation of eddy current, and the same effect as in the embodiment of the present invention can be obtained when mounting the lead wire, Modifications other than the present embodiment are included.

[0022]

As described in detail above, according to the present invention,
So that the terminal and the flange of the drum core do not contact
In addition, since it can be arranged accurately, the magnetic flux passing through the terminal portion is small. In addition, since a left-right asymmetrical split groove is provided in the terminal part,
The spring property of the lead wire mounting hole is improved. In other words, since the width of expansion and contraction for expanding the lead wire mounting hole can be made larger than that of the conventional one, the lead wire is sandwiched between the lead wire mounting holes and fixed appropriately, and the temporary connection between the lead wire and the lead wire mounting hole is made. Even if vibration is applied during attachment, these positions do not shift. Therefore,
The characteristics of the chip inductor are improved without variation.

[Brief description of the drawings]

FIG. 1 is a view for explaining a lead frame for producing a chip inductor according to one embodiment of the present invention.

FIG. 2 is an explanatory diagram when a terminal section is created from a lead frame according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram when a chip-shaped inductor according to an embodiment of the present invention is mounted on a terminal portion.

FIG. 4 is an enlarged view of a terminal portion in the present invention.

FIG. 5 is a perspective view of a chip inductor according to an embodiment of the present invention.

FIG. 6 is a diagram showing only one terminal in a conventional example.

FIG. 7 is an explanatory view of a lead frame for manufacturing an inductor in a conventional example.

FIG. 8 is a diagram for explaining a state in which an inductor is mounted on a lead frame in a conventional example.

FIG. 9 is a partially cutaway view of an outer package of an inductor in a conventional example.

FIG. 10 is a diagram for explaining a chip-shaped inductor having a terminal portion provided with a notch.

11 is an external view of FIG.

FIG. 12 is a view for explaining a modification of the conventional example shown in FIG.

FIG. 13 is a diagram for explaining another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Lead frame 2 ... Continuation part 3 ... Space part 4 ... Center slit 5, 5 '... Opening 6 ... Lead wire mounting hole 7 ... Split groove 10 ....・ Terminal part 21 ・ ・ ・ Drum core 22 ・ ・ Ferrite core 23, 23 ′ ・ ・ ・ Flange 24 ・ ・ ・ Lead wire 31 ・ ・ ・ Bottom terminal part 32 ・ ・ ・ Side terminal part 41 ・ ・ ・ Outer body

Claims (2)

(57) [Claims] 1. A drum core having flanges at both ends of a ferrite core, a pair of lead wires implanted on the axis of the flange, and a winding wound around the ferrite core of the drum core. A coil having a terminal entangled with the lead wire and connected thereto, a lead wire mounting hole for mounting the lead wire, an opening narrower than the lead wire mounting hole, and an extension formed from the lead wire mounting hole. A chip-shaped inductor, comprising: a terminal portion having a left-right asymmetrical split groove; and an insulating resin outer package in which a part of the drum core, the lead wire, the coil, and the terminal portion are embedded. 2. A center slit cut along a center line of the conductor strip, an opening smaller than a diameter of a lead wire provided at a center point of the center slit, and a lead wire communicating with the opening and mounting the lead wire. A first lead wire mounting hole to be placed and a left-right asymmetric split groove communicating with the lead wire mounting hole are formed by punching a conductor strip in a point symmetric manner with respect to a center point of the center slit. A second step of forming terminal portions rising in opposite directions from the center slit; a third step of implanting a lead wire at an axis of a drum core provided with flanges at both ends of a ferrite core; Forming a coil by winding a coil around the wire, and tying both ends of the coil to the lead wire, and extending both ends of the lead wire obtained in the step by extending the opening to form a lead. A fifth step of mounting in the mounting hole, a sixth step of connecting the lead wire and the terminal portion, and a step of molding a part of the drum core, the lead wire, the coil, and the terminal to form an exterior body. A seventh step, an eighth step of separating a terminal portion exposed from the exterior body from the conductive strip, and a ninth step of bending the terminal section along the exterior body to form an external connection terminal. 2. The method for manufacturing a chip-shaped inductor according to claim 1, wherein: