JPH0227523Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a mounting structure for attaching a thin strip coil formed by winding a thin strip of copper foil many times to a printed circuit board.

[Prior art and its problems]

Generally, a coil is made by winding an insulated coated electric wire with a circular cross section around a core of a desired shape and a desired number of turns. However, in the case of the coil, even if winding is possible with the fewest voids, the wire cannot occupy a high proportion of the cross-sectional area, so the cross-sectional area becomes large compared to the required number of turns. There were flaws.

Therefore, the present applicant has proposed Japanese Patent Application No. 58-073729 and Japanese Patent Application No. 58-073729 to improve the above-mentioned drawbacks.
Nos. 249126 to 249131 and patent application 1987-119790 to
It has been filed as No. 119791.

The method of this application involves winding a wide copper foil around a core, insulating and bonding between the copper foils with an insulating agent or adhesive having a heat resistance temperature lower than the melting temperature of the solder, and then removing the core, or removing the core along with the core to a desired width. It cuts to.

The coil formed in this way has a high conductor space factor, has a constant external shape, and has an increased number of turns, resulting in high efficiency and high quality. However, in order to attach this coil to a printed circuit board, It was installed by the method shown in FIG. 2 or 3.

That is, in the method shown in FIG. 2, the winding start 1a and the winding end 1b of the coil 1 are pulled out from the coil 1, connected to the pattern 2a of the printed circuit board 2 by solder 3, and the coil 1 itself is connected to the printed circuit board 2. It is fixed using adhesive.

When using this method, the work of pulling out the winding start 1a and the winding end 1b and soldering the coil 1
This requires the work of fixing it to the printed circuit board 2, which increases the number of man-hours and poses a problem in terms of workability.

Next, in the method shown in FIG. 3, the lead wires at the winding start 1a and winding end 1b of the coil 1 are directly connected to the pattern 2a of the printed circuit board 2 by solder 3 without drawing them out.

Although this method improves workability compared to the method shown in FIG. 2, as shown in the enlarged cross-sectional view in FIG. The insulating material 1c on the end face of the coil 1 is melted, causing a shot over several turns to several tens of turns. As a result, the number of turns decreases, which has the disadvantage of deteriorating the performance of, for example, motors that utilize this coil.

(Purpose of the invention) This invention aims to correct the shortcomings mentioned above.
The purpose is to provide a groove structure for attaching a thin ribbon coil to a printed circuit board in which solder does not adhere to only the beginning and end of winding of the coil and is soldered to the pattern of the printed circuit board.

[Example of idea]

FIG. 1 shows a sectional view of essential parts showing an embodiment of the present invention, and the same reference numerals as in FIGS. 2 and 3 indicate the same parts.

What is important in the present invention is that at least one end surface of the coil 1 has a heat-resistant insulating layer 4 made of, for example, an ultraviolet curing or thermosetting epoxy resin (solder resist) that has a heat resistance temperature higher than the melting temperature of the solder 3. It is to apply.

The coil 1 configured in this manner is placed on the upper surface of the pattern 2a of the printed circuit board 2 with the heat-resistant insulating layer 4 side facing down. Next, when solder 3 is applied in a molten state to the innermost and outermost parts of the coil 1 corresponding to pattern 2a, an insulating agent (usually a thermoplastic resin with a melting temperature of 170 to 180°C) on the sides is applied. A certain polyamide resin is used.) 1c is melted,
The solder 3 is attached, and therefore, the innermost and outer peripheral portions of the coil 1 are connected to the pattern 2a by the solder 3.

Then, during this soldering, the printed circuit board 2
Since a heat-resistant insulating layer (with a melting temperature of about 300°C) 4 is coated on the end face of the coil 1 that is in contact with the pattern 2a, even if solder 3 flows into the end face of the coil 1, the heat-resistant insulating layer Since the solder 4 is not melted, the solder 3 does not adhere to the end face of the coil 1. Therefore, the solder 3 adheres only to the innermost and outer peripheral portions of the coil 1, and the number of cones of the coil 1 does not decrease.

In the above embodiment, the heat-resistant insulating layer 4 was applied only to one end surface of the coil 1, but it may be applied to both end surfaces. Of course, it is also possible to apply only the heat-resistant insulating layer 4 without forming the layer 1c.

[Effect of idea]

As described above, this invention forms an insulating layer with a heat resistance temperature higher than the solder melting temperature on the end face of a coil formed by winding a thin strip, so that the innermost and outer peripheral surfaces of the coil can be soldered to the pattern of the printed circuit board. Even if the coil is attached, the end face of the coil will not be shot by solder, and therefore the coil will not be shot even when the coil is directly attached to a printed circuit board. ), it is possible to prevent the deterioration of the performance of the coil, and since the coil is fixed to the printed circuit board at the same time as it is soldered to the pattern, the workability can be improved.

[Brief explanation of drawings]

Fig. 1 is a partially enlarged cross-sectional view showing the mounting structure of the ribbon coil on the printed circuit board according to the present invention; Fig. 2;
FIG. 3 shows a conventional mounting structure, FIG. 2 is a perspective view showing one example, and FIG. 3 shows another example, in which a is a perspective view and b is a partially enlarged sectional view of the same. 1... Coil, 2... Printed circuit board, 2a...
Pattern, 3...Solder, 4...Heat-resistant insulating layer.

Claims (1)

[Scope of utility model registration request] A heat-resistant insulating layer having a heat-resistant temperature higher than the solder melting temperature is applied to at least one end face of the ribbon coil, and the heat-resistant insulating layer side is placed in contact with a printed circuit board, so that the pattern of the printed circuit board and the coil A structure for attaching a thin strip coil to a printed circuit board, characterized in that the innermost and outer peripheral surfaces of the coil are connected by soldering.