JPH01199413A - Inductance element - Google Patents

Abstract

PURPOSE:To improve the yield rate of resin molding by a method wherein a drum core is fixed to a pair of metal plate terminals by soldering, and when the soldering is conducted, supersonic vibrations are applied to the drum core and the metal plate terminals. CONSTITUTION:A drum core 1 is fixed to a pair of metal plate terminals 4a and 4b, a coil 2 is formed by winding a copper wire around the winding groove of the drum core 1, the lead part of said drum core is electrically connected to the above-mentioned pair of metal plate terminals 4a and 4b respectively, and a part of the pair of metal plate terminals 4a and 4b and the drum core 1 including the coil 2 are sealed with heat-resisting resin 3. The above-mentioned drum core 1 fixed to said pair of metal plate terminals 4a and 4b, and when the soldering work is conducted, supersonic vibrations are added to the drum core 1 and the pair of metal plate terminals 4a and 4b. Consequently, as the fused solder 6 is easily intruded into the cavities 5 of the drum core 1 and the cavities are filled up with the solder, the drum core 1 can be firmly fixed to the metal plate terminals.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to inductance elements used in electronic circuits in various fields such as videos and televisions, and in particular to high-density packaging 1 in recent years.
The present invention provides a small and thin inductance element suitable for surface mounting.

2. Description of the Related Art A conventional inductance element having a structure as shown in FIG. 3 is well known. In FIG. 3, 31 is a drum core, and generally a sintered body of Ni--Zn ferrite is used. 32 is a coil, and the drum core 31 is wound with a copper wire having a diameter of 30 to 60 μm. Carp/L/32
The drum core 31 provided with metal plate terminals 341L, 34
b with adhesive 35, and the lead part of the coil 32 (
(not shown) are electrically connected to the metal plate terminals 34&, 34b, respectively. 33 is resin, and is a part of the drum core 31° coil/L'32 and metal plate terminals 341L and 34b.

are integrally molded.

The conventional inductance element, which has a configuration that exceeds the problem to be solved by the invention, has characteristics such as high Qo and large inductance because it is wound wire, and can be mass-produced at a relatively low cost, so it is suitable for surface mounting. It has become the mainstream inductance element for applications.

However, in the conventional inductance element, the drum core 31 is connected to the metal plate terminal 34a using an adhesive 35.

34b, if the amount of adhesive 36 applied is small, the adhesive strength will be weak and the drum core 31 will move vertically and horizontally due to the molding pressure of the resin 33, causing the drum core 31 to be exposed on the surface of the resin 33. Furthermore, when the amount of coating is increased to increase the adhesive strength, molding defects such as the adhesive 35 being exposed on the surface of the resin 33 occur, resulting in a decrease in yield.

The present invention eliminates the drawbacks of the conventional inductance elements described above and provides an inductance element with good yield.

Means for Solving the Problems In order to solve the above problems, the inductance element of the present invention is provided by fixing a drum core to a pair of metal plate terminals, winding a copper wire in the winding groove of the drum core as a fill, and forming the coil. Lead portions are electrically connected to the pair of metal plate terminals, a portion of the pair of metal plate terminals and the drum core including the coil are sealed with a heat-resistant resin, and the drum core is soldered to the drum core. Fixed to a pair of metal plate terminals,
Further, during soldering, ultrasonic vibrations are applied to the drum core and the pair of metal plate terminals during soldering.

The present invention, which has the above means, uses soldering to fix the drum core to a pair of metal plate terminals, and also applies ultrasonic vibration when the solder is melted to fill the hollow part of the drum core with the molten solder. - It produces what is called an anchor effect in general adhesion and provides strong adhesion strength, which greatly improves the yield in resin molding.

Example The present invention will be explained in detail below based on one embodiment.

FIG. 1 is a sectional view showing one embodiment of the inductance element of the present invention. In the figure, 1 is a drum core, and a coil 2 is formed by winding a copper wire a predetermined number of times around the winding groove of the drum core. The drum core 1 is fixed to the metal plate terminals 42L and 4b by soldering, and ultrasonic vibrations are applied during soldering to fill the cavity near the surface of the drum core 1 with molten solder to obtain strong adhesive strength. ing. Regarding the supply of solder, in this embodiment, the metal plate terminal 4& is used.

Electroplated solder (not shown) was used on the surface of 4b, but if there is no solder plating, solder may be supplied using cream solder, thread solder, or the like.

3 is a heat-resistant resin, which is a part of the metal plate terminals 4a and +b;
And the drum core 1 including the coil 2 is sealed.

Next, a pair of metal plate terminals 4 & in this embodiment.

4b and the drum core 1 soldering mechanism will be explained. FIG. 2 is an enlarged sectional view of the soldering part. In the figure, 1 is a drum core, which is made of a Ni-Zn ferrite sintered body. Usually, this type of ferrite has a cavity 5 inside and near the surface. The occurrence of cavities 5 in fired products (ceramics) containing ferrite cannot be avoided, and there are structural ceramics that are generally referred to as fine ceramics, in which cavities 5 are reduced as much as possible. Therefore, it is safe to say that ceramics fired by common means always have cavities 5 as shown. 4 is a metal plate terminal, and a solder 6 is provided on the surface thereof by plating.

When this solder 6 is heated and further ultrasonic vibrations are applied, the bonds between the molecules of the molten solder 6 are weakened by the ultrasonic vibrations, and the solder 6 easily enters the cavity 6 and is filled into the cavity 6. When the solder 6 hardens, the drum core 1 is firmly fixed to the metal plate terminal 4 due to the anchor effect caused by the solder 6 filling the cavity 6.

As described above, in the inductance element of the present invention, the drum core 1 is soldered to the metal plate terminals 4a and 4b, and is firmly fixed by applying ultrasonic vibration during soldering, and the drum core 1 and adhesive are firmly fixed. This eliminates molding defects where the resin is exposed on the surface of the resin 3, and improves yield. Furthermore, since the volume conventionally occupied by adhesive can be omitted, the inductance element can be made smaller and thinner.

Effects of the Invention As described above, the present invention provides an inductance element that can reduce yield, especially defects caused by molding, and at the same time can be made smaller and thinner, thereby further facilitating high-density packaging of circuit boards. This will greatly contribute to the miniaturization and thinning of electronic devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the inductance element of the present invention, FIG. 2 is an enlarged sectional view showing the soldering mechanism of the invention, and FIG. 3 is a sectional view showing a conventional inductance element. 1...Drum core, 2...Coil, 3...
·····resin. 4a, 4b, 4...metal plate terminal, 5...
...Cavity, 6...Solder.

Claims (1)

[Claims] A drum core is fixed to a pair of metal plate terminals, a copper wire is wound around the winding groove of the drum core to form a coil, the lead portions of this coil are electrically connected to the pair of metal plate terminals, and the pair of metal plate terminals is connected to the drum core. The drum core including a part of the plate terminal and the coil is sealed with a heat-resistant resin, the drum core is fixed to the pair of metal plate terminals by soldering, and ultrasonic vibration is applied to the drum core during soldering. and an inductance element soldered in addition to the pair of metal plate terminals.