JPH11186064A - Small-sized coil device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the connective processings of the terminals of the wires of small-sized coils and manufacture them with a good workability by providing core positioning portions and wire-terminals fixing portions in the lead frames having the wire drawing-out terminals of the small-sized coils. SOLUTION: In each of respective pairs of lead frames (16a, 16b) and (16a', 16b'), protrusive pieces 13 for positioning and external lead terminals 11 are obtained by press-working, etc., in an integral state. Then, forming protrusively by press-workings the projective pieces 13 for positioning a core-end surface, a protrusive piece 14 and respective protrusive pieces 17, 18 are formed in a bent way. Subsequently, the respective end portions of a square toroidal core 12, whereon windings (wires) are wound respectively in a common-mode way are positioned in the bent corner portions of the lead frames 16a, 16b, 16a', 16b' to put the respective end portions on the core-bottom surface holding protrusive pieces 18. Then, the terminals of the wires are fitted into wire- terminal sandwiching grooves 19 to fix them therein in a sandwiching way be the elastic forces of the protrusive pieces 13 and the protrusive pieces 17 for positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small coil such as a transformer, a noise filter and a choke coil, and more particularly to a small coil device using a thick wire and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a conventional electronic device, a wire diameter of a winding used for a noise filter is about 0.1 mm. This is for use in a line having an operating current of 1 to 2 A or less due to the requirements such as the shape required in the market. In such a method of connecting wires, the wires are fixed to the lead frame by fixing and soldering. In addition, Japanese Patent Application Laid-Open No. 4-183104,
There is Japanese Patent Publication No. 7-58651. In these devices, a thin wire of 0.3 mm or less is wrapped around the rising portion of the lead frame and soldered.

In recent portable information devices, the power for operation is supplied and the battery of the device is often charged. The current flowing through the DC power supply line is about 5 A. To cope with this increase in power, the wire diameter is increased to reduce the DC resistance to suppress the temperature rise, and to prevent the characteristics of the noise filter from deteriorating. As a method of connecting such a thick wire, for example, as described in Utility Model Registration No. 2547907, a method of soldering a wire through a hole of an input / output terminal bent into a substantially U-shape, Or JP-A-8-14
As described in JP-A-8959, a method in which a fitting groove is provided on a wall surface of a noise filter element housing case and a harness (covered electric wire) connected to a lead wire made of a thick wire is fitted in the fitting groove. There is.

[0004]

In the prior art, when the diameter of the wire is increased, the wire cannot be wound on the frame, and it is difficult to position the coil. Also, the method of passing the wire through the hole of the input / output terminal or the method of fitting the harness into the fitting groove of the case uses a storage case, requires processing of the case wall surface, and connects the wire terminal. The processing is not simple and does not lead to simplification of the coil manufacturing process.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a small-sized coil which can be easily manufactured with good workability even when the wire diameter of the winding is increased. An object of the present invention is to provide an apparatus and a method of manufacturing the same.

[0006]

Means for solving the above problems are as follows.

According to a first aspect of the present invention, there is provided a small coil in which a rectangular toroidal core having a through hole made of a magnetic material is wound, and a coil for holding the small coil and drawing out a winding terminal of the small coil. A lead frame having a lead terminal, a core positioning portion provided on the lead frame for positioning the rectangular toroidal core, and a winding portion of the small coil provided on a corner of a bent plate surface of the lead frame. And a winding terminal fixing portion for holding the terminal. The manufacturing method according to claim 2, a coil forming step of forming a small coil by applying a winding to a rectangular toroidal core having a through hole made of a magnetic material, and a lead terminal for pulling out a winding terminal of the small coil,
A core positioning portion that bends a lead frame to position the rectangular toroidal core from the left and right directions,
A frame forming step of forming a lead frame comprising a winding end fixing portion for holding the winding end of the small coil at a corner thereof by bending the lead frame,
A core positioning step of arranging the small coil on the lead frame and positioning the rectangular toroidal core at the core positioning section, and clamping a winding terminal of the small coil to the winding terminal fixing section, And a winding terminal fixing step of fixing the winding terminal.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing a common mode choke coil according to a first embodiment of the present invention. The rectangular toroidal core 12 of the present embodiment is made of Ni—Zn-based ferrite, Mn—Zn-based ferrite, or a dust core made of a metallic magnetic material. In addition, the square toroidal core 12
Is used to facilitate insulation between the lines L ₁ and L ₂ and not to increase the coil outer shape. The opposite two sides of the rectangular toroidal core 12 have a wire diameter of 0.3 mm.
The wires L ₁ and L ₂ having the above thickness are wound in a common mode winding, and wire terminals (winding terminals) 15 a to 15 d are drawn out above the core and soldered to external lead terminals (not shown). . The reason why the wire diameter is set to 0.3 mm or more is that the allowable current (5) flowing through the DC power supply line of the electronic device in which the common mode choke coil of the present embodiment is installed.
This is to respond to A).

Left and right 2 forming the external lead terminals 11
Pair of lead frames 16a, 16b, 16a ', 16b
Are formed at predetermined intervals on a belt-shaped connecting frame F (shown in FIG. 2), and a core positioning portion, a wire terminal fixing portion, and the like described later are erected on the connecting frame. The lead frames 16a, 16b, 16a ', 16b' are thin metal strips having elasticity and good electrical conductivity, and the surfaces thereof are plated with metal to facilitate soldering and prevent oxidation.

Here, the details of the two pairs of lead frames will be described. Since the shape of the four lead frames is point-symmetric, the lead frame 1
6a and 16b will be described. Lead frame 16a
A core side projection 17 erected from the external lead terminal 11, a core end surface positioning projection 13 bent at right angles to the projection 17, and each of the projections 13 and 17.
And a wire terminal holding groove 19 formed at a boundary portion (a corner portion of the bent plate surface) and a core upper surface suppressing projection 14 bent at the upper end of the projection 13. The bottom surface of the projection 13 is bent to form a projection 18 for holding the core bottom surface. At the upper end of the protruding piece 13, a projection 20 is formed so as to project toward the wire end holding groove 19 side.
The wire end holding groove 19 and the projection 20 form a wire end holding portion. And this protrusion 13
A cutout 13a is provided on a side surface of the core upper surface suppressing projection 14 to apply a spring force to the pressing upper surface. Reference numeral 13b denotes a fixing portion between the protruding piece 13 and the core 12, which is formed by a protruding process so as to protrude hemispherically in the core direction. The other lead frame 16b
Is substantially the same as the lead frame 16a, except that the core upper surface suppressing projection 14 is not provided here.

The core end surface positioning projection 13 formed on the lead frame presses the unwound longitudinal end surface of the rectangular toroidal core 12, and the core side projection 17 suppresses the side surface of the core. It has become. The core bottom surface holding projections 18 hold and fix the core bottom surface. Further, the protruding piece 14 for suppressing the upper surface of the core has a claw shape and presses and fixes the upper surface of the core. Also, wire terminal holding groove 1
9, a wire terminal 15c is clamped. The wire end holding groove 19 is formed by cutting off the wire drawing side of the protruding piece 13, has a groove width larger than the wire diameter, and holds the wire end. The wire terminal fixing projection 20 is provided on the core end surface positioning protrusion 13 at the upper end of the wire terminal holding groove 19 to prevent the wire terminal held by the wire terminal holding groove 19 from rising and falling off. . The projecting pieces 13, 14, 17 and 18 are collectively referred to as a core positioning portion, and the holding groove 19 and the fixing projection 20 are collectively referred to as a wire terminal holding portion. Similarly, a wire terminal 15a is clamped on the lead frame 16b, a wire terminal 15b is clamped on the lead frame 16a ', and a wire terminal 15d is clamped on the lead frame 16b'.

The operation of clamping the wire ends will be described in detail with reference to FIGS. 3 and 4A and 4B.

As shown in FIG. 3, the wire 15a has a holding groove 1 provided at the boundary between the core side projection 17 and the core end positioning projection 13 bent perpendicularly thereto.
The projection 20 is pressed into the inside of the projection 9 and held there. The lower side facing the groove 19 is a gap Y.

That is, the wire terminal 15a on the right front side in the perspective view shown in FIG. 1 is pulled out from the bottom of the core along the side surface of the core and is held in the wire holding groove 19, as shown in FIG. As shown in the top view of FIG. 7, the core side protrusion 17 and the core end surface protrusion 13 are bent so as to be orthogonal.
When inserting the wire terminal 15a at the corner crossing with
The sheet is expanded by elastic deformation in the thickness direction indicated by an arrow in the figure, and is sandwiched by its restoring force after insertion.

Similarly, when the wire terminal 15b on the rear side of the perspective view of FIG. 1 is pulled out from above the core and inserted into the holding groove 19, as shown in the top view of FIG. The protruding pieces 17 'and the end face protruding pieces 13' are inserted and clamped by elastic deformation (indicated by arrows) in respective plate thickness directions.

Next, a method of manufacturing the common mode choke coil according to the present embodiment will be described with reference to FIGS. The lead frame includes a pair of lead frames (16a, 16b 'and 16a', 16 in FIG. 1).
b) A plurality of connecting frames F are formed at equal intervals by press working or the like so that the positioning projections 13 and the external lead terminals 11 are opposed to each other in a state where they are integrally joined. A plating process is performed on the surface of the lead frame to improve the solderability. Next, the protruding pieces 13 for positioning the core end surface are formed by pressing, and the protruding pieces 14 and 1 are formed.
7 and 18 are formed by bending (FIG. 2A).

Next, each end of the rectangular toroidal core 12 formed by winding a winding (wire) in a common mode is positioned at a bent corner of the lead frame 16a, 16b, 16a ', 16b'. And the core bottom holding projection 1
8. In addition, the square toroidal core 12
Wires L ₁ and L ₂ having a diameter of 0.3 mm or more are wound around two opposing sides, and the insulation coating on the wire ends is peeled off and preliminarily soldered. Next, the wire end is held in the wire end holding groove 19 and is held and fixed by the elastic force of the core positioning projections 13 and 17. In addition, protrusion 1
It is made so that there is a gap of about the wire diameter between 7 and the core side surface. At this time, the wires 15a and 15c coming out from under the core 12 are pulled out from below along the inner surface of the protruding piece 17, and the upper wires 15b and 15d are inserted into the groove 19 as they are. Next, the wire ends are soldered to the holding portions and connected (FIG. 2B). Thereafter, the case 24 is formed by insulation coating with a resin mold or the like, and the external lead terminals 11 are cut to a predetermined length (FIG. 2C).
In this way, a common mode choke coil having external dimensions of, for example, 7.5 mm in length, 10.0 mm in width, and 4.75 mm in height is obtained.

FIG. 5 is a perspective view showing a common mode choke coil according to a second embodiment of the present invention. In the present embodiment, the protruding piece 14 for suppressing the upper surface of the core shown in FIG. 1 is omitted so that it can be held even when the height of the core is increased. This is because the wire diameter is 0.3 mm or more, and the wire end is clamped and fixed at the boundary between the core side projection 17 and the end surface positioning projection 13, so that the wire can be fixed without pressing the upper surface of the core. is there. This simplifies the manufacturing process. Further, it is possible to cope with a change in the thickness of the rectangular toroidal core 12.

FIG. 6 is a view showing a choke coil according to a third embodiment of the present invention. The present embodiment is a one-turn choke coil corresponding to the normal mode, and a pair of lead frames 16 and 1 for fixing the rectangular toroidal core 12.
6 ′ (point-symmetrically arranged). Each lead frame has an external lead terminal 11 and a protruding piece 13 for positioning a core end face, and the protruding piece 13 has a protruding piece 2 for a core side portion.
1. Wire end holding groove 19, wire end fixing protrusion 20
Having. In this embodiment, the core end surface positioning projection 13 presses the unwound longitudinal end surface of the rectangular toroidal core 12 and is inserted into the wire terminal holding groove 19 by the elasticity of each projection. One wire end is clamped and fixed. In addition, the core side protrusion 21
Further, a core bottom holding projection (not shown) (corresponding to 18 in FIG. 1) presses and fixes the pair of opposed core side surfaces and core bottom surfaces. Here, wire terminal holding groove 1
9 is provided between the intersecting projections 13 and 21 as in the above-described embodiment, but a wire end extraction groove 19 ′ is provided on the end face side of the core-side projection 21. , In that the upper end thereof is a projection 20 for preventing lifting. The method of manufacturing the choke coil according to the present embodiment is substantially the same as that of the first embodiment, but the workability is further improved because only a pair of lead frames arranged opposite to each other can be used. I do.

FIG. 7 is a diagram showing a choke coil according to a fourth embodiment of the present invention. Although the configuration is substantially the same as that of FIG. 6, in particular, a claw-shaped core upper surface suppressing protrusion 14 a for pressing the upper surface of the rectangular toroidal core 12, a claw-shaped core bottom surface holding protrusion 14 b, 14 c for supporting the core bottom surface, and a core. It has a claw-shaped core side surface suppressing projection 14d that faces the side projection 21 and presses the core side surface. The rectangular toroidal core 12 can be securely fixed by these claw-shaped protruding pieces. The method of clamping the wire ends is the same as in the case of FIG.
The method for manufacturing the choke coil according to the present embodiment is the third method.
This embodiment is almost the same as the above-described embodiment, except that a step of bending the protruding pieces 14a to 14d is added.

FIG. 8 is a view showing a choke coil according to a fifth embodiment of the present invention. The present embodiment is a one-turn choke coil corresponding to the normal mode, as in FIG. 6, but is formed by winding three sides of the rectangular toroidal core 12 and placing it vertically. Further, the protruding pieces 13 for positioning the core end faces of the pair of lead frames 16 and 16 ′ which are arranged to be symmetrical with respect to the point press the core end faces in the longitudinal direction which are not wound. Each of the core side protrusions 21 presses the pair of opposing core side surfaces, and the wire ends held by the wire end holding grooves 19 are connected to the respective protrusions 13, 1.
7 and fixed by elastic force. Further, the core bottom surface in the case where the core is vertically placed is supported and fixed by the core bottom surface holding projection 23 (not shown). Also in the present embodiment, the use of a pair of lead frames arranged opposite to each other improves the workability as in the case of FIG.

FIG. 9 is a diagram showing a choke coil according to a sixth embodiment of the present invention. The configuration is substantially the same as that of FIG. 8, but includes a core-side projection 22 that faces the core-side projection 17 and presses the side surface of the core 12 in the case of the vertical installation. Thereby, it is possible to fix more securely than the embodiment of FIG. Although the core bottom holding projection 23 for supporting the core bottom has a slightly different shape from that of the embodiment of FIG. 8, the function is almost the same. The method of clamping the wire ends is the same as in the case of FIG.

According to the common mode choke coil and the method of manufacturing the same of the first and second embodiments, the lead frame is provided with the core positioning portion and the lead terminal fixing portion,
Since the wire end is inserted into the wire end holding groove and held by utilizing the elastic deformation of the intersecting protruding pieces, even if a wire with a large diameter is used, the connection process of the wire end is easy, and work is possible. Performance can be improved. Further, the wire terminal holding projection can prevent the wire terminal from floating above the wire terminal holding groove, and can be applied to a wire having a larger diameter. Further, even if the protrusion for holding down the core upper surface that presses the upper surface of the core as in the second embodiment is omitted, since the wire end is securely held and fixed by the wire end holding portion, there is no problem in positioning. Therefore, the wire is not loosened or the core does not come off during the manufacturing, and the manufacturing process can be further simplified. Further, by setting the height of the lead frame sufficiently higher than the upper surface of the mounted rectangular toroidal core, it is possible to cope with a change in the thickness of the core.

Further, according to the choke coil and the method of manufacturing the same according to the third and fifth embodiments, the lead frame is paired, and the core upper surface suppressing projection for pressing the core upper surface can be omitted. Better. And the first
Also, similarly to the second embodiment, a wire terminal having a large wire diameter can be securely fixed by the elasticity of the lead terminal fixing portion and the lead frame.

According to the fourth and sixth embodiments,
By adding the claw-shaped projections for holding the upper surface of the core and the projections for positioning the side surfaces, each surface of the core can be securely fixed, and a wire terminal having a large wire diameter can be fixed as described above.

[0027]

As described above, according to the present invention,
In a small coil device such as a common mode choke coil having a rectangular toroidal core wound with a thick wire and a choke coil compatible with a normal mode, a core positioning portion and a lead terminal fixing portion are provided on a lead frame,
The wire ends are inserted into the holding grooves provided at the corners of the plate surface where the lead frame is bent, and they are held and fixed using the elastic deformation of each plate surface, so it is easy to fix even thick wires, Workability can be improved. Further, since a fixing protrusion is provided on the wire terminal holding portion to prevent the wire terminal inserted into the wire terminal holding groove from rising, the wire is prevented from coming off, and the wire can be easily and reliably fixed. Even when the rectangular toroidal core is placed vertically, the connection process of the wire terminal can be simplified for the same reason, and the workability can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a common mode choke coil according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of manufacturing the common mode choke coil of FIG.

FIG. 3 is a view for explaining a state in which a wire terminal is clamped according to the first embodiment of the present invention.

FIG. 4 is a top view for explaining a sandwiched state of a wire terminal according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a choke coil according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing a choke coil according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a choke coil according to a fourth embodiment of the present invention.

FIG. 8 is a perspective view showing a choke coil according to a fifth embodiment of the present invention.

FIG. 9 is a perspective view showing a choke coil according to a sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 External lead terminal 13 Core end surface positioning projection 14, 17, 18 Projection 15 Wire 15a-15d Wire terminal 16a, 16b, 16a ', 16b' Lead frame 19 Wire terminal holding groove 20 Wire terminal fixing projection

Claims (2)

[Claims] 1. A lead frame having a small coil formed by winding a rectangular toroidal core having a through hole made of a magnetic material, and a lead terminal for holding the small coil and drawing out a winding terminal of the small coil. A core positioning portion provided on the lead frame for positioning the rectangular toroidal core; provided at a corner of a bent plate surface of the lead frame;
And a winding terminal fixing portion for holding a winding terminal of the small coil. 2. A coil forming step of forming a small coil by winding a rectangular toroidal core having a through hole made of a magnetic material, a lead terminal for drawing out a winding terminal of the small coil, and a lead frame being bent. A lead frame composed of a core positioning portion for positioning the rectangular toroidal core between the left and right directions and a winding terminal fixing portion for bending the lead frame and holding the winding terminal of the small coil at the corner thereof. A frame forming step of forming; a core positioning step of arranging the small coil on the lead frame and positioning the rectangular toroidal core at the core positioning section; and fixing a winding terminal of the small coil to the winding terminal. A coil end fixing step of fixing the winding end by holding the coil at a portion thereof. Method of manufacturing location.