JPH05198438A - Chip-shaped inductor and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent the protruding and the position deviation of a lead wire by providing the constitution, wherein a hole is opened, the lead wire is inserted into a lead-wire mounting hole, then, the lead wire is held, and the lead wire is provided apart from a drum core. CONSTITUTION:Flanges 23 are provided at both ends of a ferrite magnetic core 22 in a drum core 21. A pair of lead wires 24 are implanted and provided at the centers of the flanges 23. A winding is wound around the ferrite magnetic core 22 of the drum core 21. Both terminals of the winding are hooked and connected on the lead wires 24 and a coil is formed. A terminal part 10 has a lead-wire mounting hole 6 for mounting each lead wire 24, an opening 5, which is narrower than the lead-wire mounting hole 6, and cut groove, which is asymmertical on the right and left sides and formed by the extension from the lead-wire mounting hole 6. The drum core 21, the lead wires 24, the coil and the parts of the terminal parts 10 are embedded in an insulating-resin external mounting body 41. This inductor is constituted of these parts. Thus, the expanding and contracting width for broadening the lead-wire mounting hole can be increased. Therefore the inductor is adequately fixed, and the positions of the terminal parts are not deviated.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art As electronic devices have become smaller and lighter, it has been desired to make inductors that can be used with an automatic inserter together with resistors or capacitors. 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 the exterior body of the inductor in the conventional example. A conventional chip-shaped inductor will be described with reference to FIGS. 7 to 9. 7 to 9, first, a strip member made of a metal plate is punched out to form the lead frame 101. That is, the lead frame 101 includes a continuous portion 102 for preventing the strip members from being separated when punching the strip member, a lead wire mounting portion 103 for mounting a lead wire, which will be described later, and a terminal portion 104. It comprises a cut-and-raised part 105.

On the other hand, the chip-shaped inductor element body includes a drum core 111 formed of a ferrite magnetic core and flanges provided at both ends thereof, a coil 112 in which a conductor wire whose surface is insulated is wound around the ferrite magnetic core, and A pair of lead wires 1 attached to the shaft center of the flange with an adhesive.
13 and 13. Then, both ends of the coil 112 are entwined with the lead wire 113 and then connected to the lead wire 113 by, for example, soldering or the like. Then, the chip-shaped inductor body is attached to the lead frame 101.
Is mounted on the lead wire mounting portion 103 of the lead frame 1
01 and the lead wire 113 are connected by soldering or spot welding. Then, the chip-shaped inductor body is entirely molded by an insulating resin exterior body 122 except for the terminal portion 104 of the lead frame 101. Further, the terminal portion 104 protruding from the mold is bent along the mold to become the external connection terminal 121 of the chip-shaped inductor. Regarding the chip-shaped inductor as described above, for example, Japanese Unexamined Patent Publication No.
There is detailed description in Japanese Patent No. 50404.

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 having a notch. Figure 1
1 is an external view of FIG. In FIGS. 10 and 11, the coil 132 is wound around the drum core 131. The terminal portion 133 connected to a lead frame (not shown) is provided with a cutout portion 134. The drum core 131 is placed so that a part of the drum core 131 falls into the cutout portion 134. After that, coil ends 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 by the insulating resin exterior body 136, leaving a part of the terminal portion. The external connection terminal 1 is formed by bending the terminal portion exposed from the mold inward along the exterior body 136.
Mold 35 and 135 '.

FIG. 12 is a diagram for explaining a modification of the conventional example shown in FIG. 10 and 12, the same parts are designated by the same reference numerals. 12 is different from the chip-shaped inductor of FIG. 10 in that the terminal portion 13
3 is that both ends of the notch portion 134 in FIG. 3 are cut and raised. The cut-and-raised portion 151 can stably support the drum core 131 together with the cutout portion 134. The chip-shaped inductor shown in FIGS. 10 to 12 is disclosed in, for example, JP-A-59-144.
No. 108 publication has detailed description.

FIG. 13 is a diagram for explaining another conventional example. In FIG. 13, the chip-shaped inductor body is cut and raised in parallel from a drum core 161, a coil (not shown), a lead wire 162 implanted in the shaft center of a flange of the drum core 161, and a lead frame (not shown). The lead wire mounting portion 163, which is bent and further mounts the lead wire 162, and the terminal 165 having the base portion of the cut and raised portion 164 formed by being cut and raised in parallel from the lead frame as a terminal. Composed. The end of the coil (not shown) is entangled with the lead wire 162. Then lead 162
Are soldered or welded to the lead wire mounting portion 163. The chip-shaped inductor element body thus produced is molded by the exterior body 166, leaving the terminal 165. Then, the terminal 165 is bent along the surface of the exterior body 166 to form a chip-shaped inductor as shown in FIG. The chip-shaped inductor shown in FIG. 13 is disclosed, for example, in 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 is consumed as an eddy current on the conductor surface of the terminal portion 104 by forming an open magnetic path after passing through the terminal portion 104. For this reason, the chip-shaped inductor has a problem that the quality factor and the inductor value thereof are lowered. Further, in the above-mentioned conventional example, since the lead wire mounting portion 103 on which the lead wire 113 is mounted has only the thickness of the plate member, there is a problem that it is difficult to solder or spot weld the both. Furthermore, when the lead wire 113 is mounted on the lead wire mounting portion 103 by the automatic manufacturing machine, the lead wire 113 is not always positioned symmetrically. Even if the lead wire 113 is arranged in the correct position, the position thereof is displaced when some vibration is applied. Therefore, 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. 6, the terminal portion 61
Is a lead wire mounting portion 62 on which the lead wire 113 is mounted,
It is composed of an opening 63 narrower than the lead wire mounting portion 62 and a vertical split groove 64 communicating with the lead wire mounting portion 62. Then, the lead wire 113 is placed on the lead wire placing 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 that is narrower than its width.
Is spread on the lead wire mounting portion 62 while widening the width thereof by the vertical dividing groove 64. Therefore, even if the diameters of the lead wires 113 are slightly different, the lead wires 113 are mounted on the lead wire mounting portion 62 and are 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 / contraction width that spreads due to the spring property, and it has been difficult to provide a moderate spring property for holding the lead wire.

Further, in order to reduce the eddy current generated in the terminal portion 133, the chip-shaped inductor shown in FIGS. 10 to 12 has been developed. As described above, in this chip-shaped inductor, a lead wire is not provided on the flange of the drum core 131, and a pair of flat plates protruding from the lead frame is provided with a notch portion 134 having a width slightly smaller than the diameter of the flange. The flange is placed on. Therefore, since the terminal portion 133 is not parallel to the flange portion of the drum core 131, the eddy current is generated.
It is only a portion corresponding to the end area of the terminal portion 133. Therefore, as the chip-shaped inductor, a larger inductor than that shown in FIGS. 7 to 9 can be obtained. However, for the drum core 131 or the tubular core without the lead wire, the conventional winding machine for fixing the lead wire portion to manufacture the coil 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, the diameter of the flange varies depending on the type of inductor, which complicates the structure of the chuck and makes it difficult to center the coil when winding it. In addition, the cutout portion 134 formed in the terminal portion 133.
There is also a problem that the notch width must be changed for each type of chip-shaped inductor. Furthermore, coil 1
The 32 terminals 132 ′ required another processing step different from the coil winding in which the terminal portion 133 was soldered.

In the conventional example shown in FIG. 13, in order to simplify the connection between the lead wire mounting portion 103 and the lead wire 113 shown in FIGS. 7 to 9, the lead wire mounting is made of a plane parallel to the lead wire 113. A holder 163 is provided. However, regarding the connection between the lead wire 113 and the lead wire mounting portion 163, the above-mentioned problem is solved, but the above-mentioned problem that the inductor is deteriorated due to the eddy current is not yet solved.

The present invention is intended to solve the above problems, and in a chip-shaped inductor having lead wires implanted in the flange of a drum core, improves the inductor characteristics and prevents the terminals from being displaced. It is an object to provide an inductor and a manufacturing method thereof.

[0012]

(First Invention) In order to achieve the above object, a chip-shaped inductor according to the present invention has a flange (22 in FIG. 3) at both ends of a ferrite magnetic core (22 in FIG. 3).
3) provided drum core (21 in FIG. 3), a pair of lead wires (24 in FIG. 3) implanted in the shaft center of the flange (23), and a ferrite core (22) of the drum core (21). And a coil in which both ends of the winding are wound around the lead wire (24) and connected, and a lead wire (2
4) lead wire mounting hole for mounting (6 in FIGS. 2 and 3)
And an opening narrower than the lead wire mounting hole (6) (5 in FIGS. 2 and 3) and a left-right asymmetric split groove extended from the lead wire mounting hole (6) (FIGS. 2 and 3). 7) and a terminal part (10 in FIGS. 2 and 3), and an insulating resin exterior body in which a part of the drum core (21), the lead wire (24), the coil, and the terminal part (10) is embedded. (Fig. 5
41) and

(Second Invention) A method of manufacturing a chip-shaped inductor according to the present invention comprises a center slit (4 in FIG. 1) cut along a center line of a conductor strip (1 in FIG. 1) and the center. An opening (5 in FIG. 1) narrower than the diameter of the lead provided at the midpoint of the slit (4) 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), the central slit (4). 2) is formed by punching out a conductor strip symmetrically with respect to the middle point, and a terminal portion (1 in FIG. 2) standing up from the central slit (4) in mutually opposite directions.
0), a second step of molding the ferrite core (22), a third step of implanting a lead wire (24) on the axis of a drum core (21) having flanges (23) at both ends thereof, and the drum core (21). 21) winding a winding to form a coil, and entwining both ends of the coil with the lead wire (24), and the lead wire (24) obtained in the step.
Step (5) in which both ends of the lead wire are placed in the lead wire placement hole (6 in FIG. 1) with the opening (5) widened;
And a terminal portion (10) are connected to each other, and a seventh step of molding the drum core (21), the lead wire (24), the coil, and a part of the terminal to form the exterior body (41). , The terminal portion (1) exposed from the exterior body (41)
0) from the conductor strip (1) and a ninth step of bending the terminal portion (10) along the exterior body (41) to form external connection terminals (31, 32).
It consists of a process and.

[0014]

[Operation] (First invention) Flanges are formed at both ends of the drum core with the shaft center interposed therebetween. Then, lead wires are planted on the central axes of both ends of the flange with, for example, an adhesive. The coil is wound around the magnetic core of the drum core, and after wrapping both ends of the coil around the lead wire, that portion is soldered. On the other hand, a molded lead wire mounting hole and an opening having a diameter smaller than that of the lead wire mounting hole are formed in the terminal portion cut and raised from the lead frame. Then, the lead wire is held in the lead wire mounting hole so as to spread the opening. The elasticity of holding the lead wire is generated by a left-right asymmetric split groove communicating with the lead wire mounting hole. That is, the terminal portion connected to the lead wire mounting hole, by the split groove,
Since one side is narrow, move so that only one side opens. Then, the lead wire and the lead wire mounting hole are connected by, for example, spot welding. Next, the exterior body is applied with an insulating resin, leaving a part of the terminal portion.
The terminal portion exposed from the exterior body is separated from the conductor strip and then bent along the exterior body to form the external connection terminal of the chip-shaped inductor. In the chip-shaped inductor having such a configuration, the lead wire is sandwiched from both sides after opening the opening and entering the lead wire mounting hole. Therefore,
The lead wire can be accurately placed away 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. Further, since the lead wire mounting hole can provide elasticity, even if vibration occurs during the temporary fixing of the lead wire and the lead wire mounting hole, the lead wire pops out from the terminal portion or is positioned. There is no gap. Therefore, in the chip-shaped inductor of the present invention, the inductance can be increased and the lead wire can be properly 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 which is provided symmetrically with respect to the center point of the center slit, and has a narrow opening. A left-right asymmetric split groove communicating with the lead wire mounting hole is formed by punching a die. After that, the portions to be the terminal portions are erected on both sides from the central slit provided in the center line of the conductor strip. On the other hand, lead wires are planted in the shaft centers of the flanges provided at both ends of the drum core made of a ferrite magnetic core. A coil is wound around the axis of the drum core, and both ends of the coil are entwined 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. After that, the lead wire is held in the lead wire mounting hole by the elasticity of the split groove. Next, the lead wire and the lead wire mounting 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 exterior body is separated from the lead frame and then bent along the exterior body to form the external connection terminal of the chip-shaped inductor. In the chip-shaped inductor manufactured as described above, since the terminal portion parallel to the flange of the drum core is accurately arranged, the magnetic flux is less likely to decrease.

[0016]

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

FIG. 2 is an explanatory diagram for forming a terminal portion from a lead frame which is an embodiment of the present invention. In FIG. 2, first, the central slits 4 are pressed in mutually opposite directions by, for example, a mold. That is, as shown in FIG. 2, the terminal portion 10 is erected upward. After that, the base portion of the terminal portion 10 is erected to form the terminal portion 10 shown in FIG.

FIG. 3 is an explanatory view when mounting the chip-shaped inductor, which is one embodiment of the present invention, on the terminal portion.
In FIG. 3, the chip-shaped inductor body includes a magnetic core 22 made of ferrite and flanges 23, 23 'on both ends thereof.
A drum core 21 including: a lead wire 24 that is planted in the axial center of the flanges 23 and 23 ′ of the drum core 21; a coil (not shown) wound around the magnetic core 22 of the drum core 21; It is composed of a coil end (not shown) connected by being entwined with the wire 24. The lead wire 24 and the coil end entwined with the lead wire 24 are connected by, for example, soldering. The lead wire 24 of such a chip-shaped inductor body
Are held by the lead wire mounting holes 6 of the terminal portion 10 shown in FIG.

FIG. 4 is an enlarged view of the terminal portion in the present invention. In FIG. 4, the terminal portion 10 will be described in more detail. The lead wire mounting hole 6 formed in the terminal portion 10 has an opening 5 in the upper portion thereof. Then, the opening 5 is made slightly narrower than the diameter of the lead wire. A split groove 7 is communicated with the lead wire mounting hole 6 in a left-right asymmetric manner. Therefore, when the lead wire 24 spreads the opening 5 and is inserted into the lead wire mounting hole 6, it is easy to rotate in the arrow direction shown in FIG. 4 about the narrow portion 11 of the terminal portion 10 as an axis. .. However, it does not rotate in the direction opposite to the arrow shown in FIG. 4 around the wide reference numeral 12 of the terminal portion 10 as an axis.
That is, since the eleven parts having the narrow width are provided, the spring property of the lead wire mounting hole 6 can be improved.

FIG. 5 is a perspective view of a chip-shaped inductor which is 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, the two are connected by spot welding. Thereafter, with the lead frame 1 connected, a drum core 21, a lead wire 24, around which a coil (not shown) is wound, for example, with a phenol resin or the like,
And a part of the terminal portion 10 is molded to form the outer package 41. Next, the terminal portion 10 protruding from the exterior body 41
Is separated from the lead frame 1 and then bent outward along the exterior body 6 to form the bottom terminal portion 31 and the side terminal portion 32. Such a chip inductor is
The bottom terminal portion 31 is soldered to a wiring pattern on a circuit board (not shown). During this soldering, the solder wraps around from the bottom terminal portion 31 to the side end portion 32. Therefore, since the solder that has entered the surrounding area has a stronger mounting strength and can be visually recognized from the side portion, it is possible to confirm the soldering. The winding portion in FIG. 2 is placed in the lead wire placement 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 above, 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 claims. For example, if the shape of the slit or the lead wire mounting hole with respect to the lead frame and the angle of the split groove are such that no eddy current is generated and the same effect as that of the embodiment of the present invention is provided when mounting the lead wire, Modifications other than this embodiment are included.

[0022]

As described in detail above, according to the present invention,
Make sure that the terminal and the flange of the drum core do not come in contact with each other.
Moreover, since it can be arranged accurately, there is little magnetic flux passing through the terminals. Also, because the left and right asymmetrical split groove is provided in the terminal part,
The spring property of the lead wire mounting hole is improved. That is, since the expansion / contraction width 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 is appropriately fixed, and the lead wire and the lead wire mounting hole are temporarily fixed. Even if vibration is applied during attachment, these positions do not shift. Therefore,
The characteristics of the chip-shaped inductor do not vary and are improved.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a lead frame for manufacturing a chip-shaped inductor that is an embodiment of the present invention.

FIG. 2 is an explanatory diagram when creating a terminal portion from a lead frame that is an embodiment of the present invention.

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

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

FIG. 5 is a perspective view of a chip-shaped inductor that is an embodiment of the present invention.

FIG. 6 is a diagram showing only one terminal portion 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 exterior body 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 diagram for explaining a modification of the conventional example shown in FIG.

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

[Explanation of symbols] 1 ... Lead frame 2 ... Continuous portion 3 ... Space portion 4 ... Central 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 ...・ Exterior body

Claims (2)

[Claims] 1. A drum core in which a flange is provided at both ends of a ferrite core, a pair of lead wires implanted in the shaft center of the flange, and a winding is wound around the ferrite core of the drum core. A coil in which a terminal is entwined with the lead wire and connected, a lead wire mounting hole for mounting the lead wire, an opening narrower than the lead wire mounting hole, and extended from the lead wire mounting hole. A chip-shaped inductor comprising: a terminal portion having a left-right asymmetric split groove; and an insulating resin exterior body 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 the center line of the conductor strip, an opening narrower than the diameter of the lead wire provided at the midpoint of the center slit, and a lead wire communicating with the opening. A lead wire placement hole to be placed and a left-right asymmetric split groove communicating with the lead wire placement hole are respectively formed by punching a conductor strip point-symmetrically with respect to the midpoint of the central slit. A second step of forming terminal portions standing upright in opposite directions from the central slit, a third step of implanting a lead wire in an axial center of a drum core having flanges at both ends of a ferrite magnetic core, and the drum core Forming a coil by winding a wire around the wire, and wrapping both ends of the coil around the lead wire; and opening both ends of the lead wire obtained in the step by expanding the opening. A fifth step of placing the lead wire in the placement 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 outer package. From 7 steps, 8 step of separating the terminal part exposed from the exterior body from the conductor strip, and 9 step of bending the terminal part along the exterior body to form an external connection terminal. The method for manufacturing a chip-shaped inductor according to claim 1, wherein