JPS638603B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of fixing a coil terminal suitable for a chip type inductor or the like.

In recent years, fixed inductors, like various electronic components, have become smaller, and so-called chip-type inductors are now being used, in which plate-shaped electrodes provided on the surface of the main body are brought into surface contact with the conductive pattern on a printed circuit board and soldered. It's coming. Before inductors were made into chips, the end of the coil was temporarily fixed by winding it around a terminal pin implanted in a base, etc., and then the coil was assembled by dipping this wound part in molten solder. The terminal was connected and fixed to the terminal pin. However, in the case of chip-type inductors, the electrodes for connection with the outside are flat and formed by printing and baking on the surface of the main body, so it is impossible to wrap the coil terminals and it is necessary to temporarily fix them. I can't. However, soldering both ends of a coil after winding to the electrodes at once without temporarily fixing them is extremely inefficient and time-consuming, and it is also difficult to automate the winding process. It was becoming an obstacle. However, if a part of the electrode of the chip-type inductor is made to protrude from the main body and the coil end is wound around this protrusion, it is possible to temporarily secure the end of the coil as in the conventional case. However, since a chip-type inductor is extremely small with a side of about 3 to 4 mm, if it is configured in this way, it will not only be difficult to wind the coil end around the protruding part of the electrode, but also the electrode A problem arises in that the entire inductor becomes larger due to the protrusion.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for fixing a coil terminal, which can temporarily fix the coil terminal without winding the coil terminal around an electrode.

A feature of the present invention for achieving this purpose is that a synthetic resin solution that is produced by dissolving a synthetic resin that thermally decomposes and vaporizes at high temperatures in an organic solvent is applied to the surface of the electrode. The purpose of this method is to form a synthetic resin layer covering the coil, and use the adhesive function of this synthetic resin layer itself to temporarily fix the ends of the coil.

Hereinafter, the present invention will be explained with reference to illustrated embodiments. Figures 1A to 1D show each step in order, and Figure 1A shows an example of a bobbin for a chip-type inductor. The bobbin 10 is made of a magnetic material,
It has rectangular flanges 14 integrally formed above and below the winding shaft 12. An electrode 20 made of silver or the like is provided on the upper surface of one flange 14 by printing, baking, vapor deposition, or other means.

In the method for fixing a coil terminal according to the present invention, first, a synthetic resin solution is applied to the surface of the electrode 20 provided on the bobbin 10 and dried, thereby forming a synthetic resin layer 3 as shown in FIG.
form 0. This synthetic resin solution preferably has an adhesive function when heated to about 100°C to 150°C, and is heated to an even higher temperature (about 300°C).
A synthetic resin that undergoes thermal decomposition and vaporizes when heated to, for example, a polyamide resin dissolved in an organic solvent is used. Ethylene glycol, benzyl alcohol, and the like are suitable as organic solvents for polyamide resins. The synthetic resin layer 30 only needs to be applied to the surface of the electrode 20, but
Since the size of the bobbin 10 itself is small, it is advantageous from the viewpoint of workability to apply the synthetic resin solution to the entire upper part of the bobbin 10 as shown in FIG. Next, the coil 40 is wound around the winding shaft 12 of the bobbin 10 having the dried synthetic resin layer 30, and the end 42 of the coil 40 is pulled out above the bobbin 10. Then, with the end 42 of the coil pressed against the upper surface of the electrode 20 covered with the synthetic resin layer 30, the end 42 of the coil is connected to the end 42 of the synthetic resin layer 30 by applying a heated iron or by current welding. 100℃
The synthetic resin layer 30 is heated to about 150 DEG C. to melt it, and the ends 42 of the coil at the beginning and end of the winding are adhered onto the electrode 20 on the surface of the melted synthetic resin layer 30, and the excess portions of the ends 42 of the coil are cut off. Then, it becomes as shown in C, and the terminal 42 of the coil 40 is connected to the electrode 20.
It will be in a state where it is temporarily fixed on top. An enlarged cross-section at this time is shown in FIG. 2. That is, the coil wire 42a is coated with a synthetic resin coating 42b such as polyurethane;
b and the synthetic resin layer 30 are in a bonded state. Next, when this bobbin 10 is turned upside down and the electrode 20 portion is immersed in molten solder, the synthetic resin layer 30 is heated to a high temperature of around 300°C, causing thermal decomposition and vaporization, as shown in FIG. The terminal 42 of the coil 40 is soldered 5 to the electrode 20 as shown in FIG.
A chip type inductor connected and fixed by 0 is completed. During this high-temperature treatment, the coating 42b is also melted and removed, so that the coil wire 42a is fixed onto the electrode 20 by the solder 50, as shown in an enlarged view in FIG.

In the above example, the synthetic resin layer was heated to melt its surface and bond the end of the coil. However, it is also possible to apply an organic solvent on top of the synthetic resin layer. The surface of the synthetic resin layer softens to provide an adhesive function, and then quickly dries and hardens, so that coil terminals can be temporarily fixed in the same way. Furthermore, the material of the synthetic resin solution is not limited to polyamide resin, but may also be polyurethane resin, polycarbonate resin, or the like. Although the above description has been made using a chip type inductor as an example, it goes without saying that the present invention can be applied to other electronic components having coils.

As described above, according to the present invention, the coil terminal can be quickly temporarily fixed by a simple operation such as pressing the coil terminal against the synthetic resin layer coated on the electrode and applying a heated iron. For example, it can be connected and fixed to an electrode simply by immersing it in molten solder. Therefore, it is possible to easily automate the manufacturing process of chip-type inductors, etc., and mass productivity can be significantly improved. Further, the bobbin after the electrode is coated with a synthetic resin layer is extremely convenient for manufacturing, since oxidation and sulfidation of the electrode surface are prevented even if the bobbin is stored for a long period of time.

[Brief explanation of the drawing]

Figures 1A to 2D are diagrams showing the manufacturing process of a chip-type inductor to which the present invention is applied, Figure 2 is an enlarged front sectional view of the inductor in Figure 1C, and Figure 3 is an enlarged view of the inductor in Figure 1D. FIG. DESCRIPTION OF SYMBOLS 10... Bobbin, 20... Electrode, 30... Synthetic resin layer, 40... Coil, 42... Coil terminal, 50... Solder.

Claims (1)

[Claims] 1 A synthetic resin solution that is created by dissolving a synthetic resin that thermally decomposes and vaporizes at high temperatures in an organic solvent is applied to an electrode installed on a bobbin and dried to form a synthetic resin layer that covers the surface of the electrode. Next, the coil is wound around a bobbin, the surface of the synthetic resin layer is melted, and the ends of the winding start and end of the coil are temporarily fixed by adhering the melted synthetic resin layer onto the electrode. A method for fixing a coil terminal, characterized by heating and removing the resin layer and simultaneously soldering the coil terminal to an electrode.