JPH07245227A - Production of chip coil - Google Patents

Abstract

PURPOSE:To obtain a chip coil in which no solder projection is generated in its flange part. CONSTITUTION:A chip coil consists of a core 2 and a wound wire 20. The flange part 4 of the core 2 is provided with grooves 6-8, where electrodes 13-15 are prepared on their wall surfaces and bottom surfaces respectively. The coil 1 is dipped in a melted solder bath so that molten solder adheres on the surfaces of the electrodes 13, 15. Then the coil 1 is given a force in one direction in order to shake excessive molten solder off with the inertia. Thus, a solder coating film of appropriate film thickness is formed on the electrodes 13-15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chip coil, and more particularly to a method for manufacturing a chip coil which is surface-mounted on a printed wiring board or the like and constitutes various electronic circuits.

[0002]

2. Description of the Related Art Conventionally, as a method of coating a solder by, for example, soldering a winding terminal end to an external electrode provided on a flange portion of a chip coil, a molten solder is applied to the external electrode After the attachment, there is a method of wiping off excess molten solder using silicon rubber or the like. However,
This method has a problem that the number of steps is large and the manufacturing cost is high.

Therefore, a method has been proposed in which molten solder is adhered to an external electrode and then a force in a predetermined direction is applied to the core to shake off the molten solder. However, simply applying a force in a predetermined direction to the core may not sufficiently shake off the molten solder, an excessive amount of the solder coating film may be formed on the external electrode, and a solder protrusion may be formed on the flange portion. The solder protrusion means a solder that significantly protrudes from the outer dimension of the collar portion. When such a chip coil is surface-mounted on a printed wiring board or the like, there arises an inconvenience that a soldering failure called a tombstone phenomenon sometimes occurs.

Therefore, an object of the present invention is to provide a method of manufacturing a chip coil in which a solder protrusion is not formed on the collar portion.

[0005]

In order to solve the above problems, in the method of manufacturing a chip coil according to the present invention, an external electrode is provided in the recess provided in the flange of the core, and the molten solder is applied. After being attached to the external electrode, a force in a predetermined direction is applied to the core so that excess molten solder is shaken off from the external electrode.

By the above method, the molten solder attached to the external electrode moves to the end of the external electrode while the excess molten solder is regulated by the side wall of the recess when a force is applied to the core in a predetermined direction. It will be easily shaken off. Then, even if the thickness of the solder coating film formed on the external electrode is increased, the apparent film thickness is reduced by the depth of the recess, and the occurrence rate of the solder protrusion is suppressed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a chip coil according to the present invention will be described below with reference to the accompanying drawings. Figure 1
As shown in FIG. 1, the chip coil 1 is roughly composed of a core 2 and a winding wire 20. The core 2 is the body 3 and the body 3
Has flanges 4 and 5 provided at both ends thereof, respectively.
The upper surface of the collar portion 4 is the mounting surface 4 a of the chip coil 1.
Grooves 6, 7, and 8 having a rectangular cross section are provided on the left and right sides and the center of the mounting surface 4a over both ends in the width direction of the collar portion 4. In order to secure the mechanical strength of the core 2, the grooves 6-8
The depth is preferably set in the range of 0.05 to 0.1 mm. An input electrode 13, an output electrode 14, and a ground electrode 15 are provided on the wall surface and the bottom surface of the grooves 6, 7, and 8, respectively. Further, the electrodes 13 and 14 are mounted on the mounting surface 4
It extends to the end faces 4b and 4c adjacent to a. These electrodes 13 to 15 may be provided by coating and drying by means such as screen printing, or by means of thin film forming means such as sputtering, vapor deposition or chemical vapor deposition.

As the material of the core 2, a magnetic material or a dielectric material is adopted. In this example, a dielectric material was used. The winding wire 20 is wound around the body portion 3 of the core 2, and the end portions 20a and 20b thereof are respectively connected to the electrode 1
It is electrically connected to and fixed to 3, 14 by means such as crimping, welding or soldering. The winding 20 is made of a conductive wire material coated with an insulating coating film such as polyurethane.

The chip coil 1 having the above structure is immersed in a molten solder bath with the mounting surface 4a facing down. In this example, the terminal ends 20a and 20b of the winding 20 are connected to the electrode 1
It is immersed for soldering to 3,14. Molten solder 25 is attached to the surfaces of the electrodes 13 to 15 of the chip coil 1 as shown in FIG. Next, a force in the direction of arrow a is applied to the chip coil 1. The excess molten solder moves to the end portions of the electrodes 13 to 15 while being restricted by the side walls of the grooves 6 to 8 by the inertial force and not spreading to other portions. Then, the excess molten solder that has moved to the ends of the electrodes 13 to 15 is
˜15, the solder coating film 25 ′ having a proper thickness is formed on the electrodes 13 to 15 as shown in FIG.
Is formed. Moreover, if the solder coating film 25 '
Even when the film thickness is formed to be thicker than an appropriate amount, the apparent film thickness is reduced by the depth of the grooves 6 to 8, and the occurrence rate of solder protrusions is suppressed.

The chip coil 1 having the above structure has a π
Form an LC resonant circuit. That is, the input electrode 1
3 and the ground electrode 15 and between the output electrode 14 and the ground electrode 15, capacitances C1 and C2 are formed, and an inductance L is formed between the electrodes 13 and 14. FIG. 4 is an electrical equivalent circuit diagram of the chip coil 1. In particular, since the chip coil 1 has the ground electrode 15 in the groove 8, the high frequency characteristic is also improved as compared with the conventional chip coil.

The method of manufacturing the chip coil according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the gist. In particular, the shape of the recess provided in the flange portion of the core is arbitrary, and for example, a groove having a triangular cross section may be used. Further, it is not necessary to provide recesses for all external electrodes. Therefore, the recess may be provided only in the ground electrode or only in the input electrode and the output electrode.

[0012]

As is apparent from the above description, according to the present invention, the external electrode is formed in the concave portion provided in the flange portion of the core,
After the molten solder is attached to the external electrode, the excess molten solder is shaken off from the external electrode by applying a force in a predetermined direction to the core. Is easily shaken off by. Then, even if the thickness of the solder coating film formed on the external electrode becomes thicker, the apparent film thickness is reduced by the depth of the recess, and the chip coil in which the solder protrusion does not occur on the flange portion is formed. can get.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a method of manufacturing a chip coil according to the present invention.

FIG. 2 is a cross-sectional view showing the manufacturing procedure following FIG.

FIG. 3 is a sectional view showing the manufacturing procedure following FIG. 2;

4 is an electrical equivalent circuit diagram of the chip coil shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Chip coil 2 ... Core 4 ... Collar part 6,7,8 ... Groove (recess) 13 ... Input electrode 14 ... Output electrode 15 ... Ground electrode 20 ... Winding 25 ... Molten solder 25 '... Solder coating film

Claims (1)

[Claims] 1. An extra electrode is provided by providing an external electrode in a recess provided in the flange portion of the core, applying molten solder to the external electrode, and then applying a force in a predetermined direction to the core. A method for manufacturing a chip coil, characterized in that solder is shaken off from the external electrodes.