JPH0760775B2 - Small coil manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a small coil with a lead terminal, which is sheathed with an insulating resin.

(Prior Art) Conventionally, this type of small coil is manufactured as follows.

A coated lead wire is wound around the core to form a coil, and terminal treatment such as coating stripping of the lead wire end and solder plating is performed. This coil is housed in a resin-molded outer case in which terminal leads are embedded, and the lead wire ends are twisted to the terminal leads and connected by a soldering method. In particular, when vibration resistance is required, the outer case is filled with insulating varnish to protect and fix it.

(Problems to be Solved by the Invention) As described above, in the small coil using the outer case, the terminal lead is apt to bend when the lead terminal is twisted and soldered to the embedded terminal lead. In particular, when supplying by a series of parts (hereinafter referred to as taping parts) that are attached at intervals on a mount for an automatic insertion machine, the terminal lead needs to be long, and the bending of the terminal lead is a fatal defect. .

Further, when the small coil is a common mode coil, at least four terminal leads are required, and since they are not arranged in the same plane, it is very difficult to supply them as taping parts.

(Means for Solving the Problems) A method for manufacturing a small coil according to the present invention is directed to a strip-shaped main frame and a comb-shaped main frame that is spaced apart in the lengthwise direction and has a gripping portion at its tip. A lead terminal frame made of a conductive metal plate consisting of the lead terminal piece group of
A rectangular core made of a high-permeability magnetic material is wound with a winding, and one end of the core has a held portion held by the holding portion of the lead terminal piece, and the held portion is electrically conductive. And a terminal of the winding is wired on the conductive pattern, and the held portion is held by the holding portion of the lead terminal piece. After being soldered and connected in a state, it is protected by a protective film made of an electrically insulating resin or wax exhibiting a low residual stress strain characteristic, and further coated with an electrically insulating resin and a resin liquid. .

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 2, the small coil element 1 has two lead wires 2 with a coating wound around the center of a rectangular core 11 in a bifilar winding. The rectangular core 11 made of a high-permeability magnetic material has four gripped portions 12 at one end thereof spaced apart from each other and having a thickness slightly larger than an opening size of a gripped portion 34 of the lead terminal frame 3 described later. There is. A conductive pattern 13 made of a conductive metal is formed on the held portion 12 by sputtering, electroless plating or the like. Furthermore, a cutout 14 is provided at the edge of the held portion 12 so as to correspond to the conductive pattern 13.

FIG. 1 shows a lead terminal frame 3 in which a plurality of lead terminal pieces 32 for sandwiching a small coil element 1 and leading out as external terminals are formed in a comb shape at regular intervals. The material of the lead terminal frame 3 is brass, beryllium copper, stainless steel,
It is made of iron or alloys thereof, which is a highly elastic and highly conductive strip-shaped metal plate and is manufactured by precision punching or etching.

In the lead terminal 3 frame 3, lead terminal pieces 32 are formed in a comb shape in a direction perpendicular to the main frame 31 at regular intervals. At the tip of the lead terminal piece 32, there is a slightly wider standoff portion 33, and further a holding portion 34 for holding the small coil element 1 is provided.

As shown in FIG. 3, the holding section 34 has a standoff section 33.
It is made by making two cuts in the lengthwise direction at the tip of the and raising the central section.

FIG. 1 illustrates three steps in order to make the manufacturing process of the present invention easier to understand. That is, (a) shows a state after molding as a lead terminal frame, and thereafter, as shown in FIG. 1 (b), in the small coil element 1, the lead wire end 21 of the winding is arranged along the conductive pattern 13. Wired. At the time of wiring, the lead wire 21 is covered by the notches 14 so that the lead wire ends are not contacted with each other, and is held by a jig (not shown) and immersed in the molten solder at a high temperature. Peel off the conductive pattern
Solder to 13. Further, the holding portion 34 of the lead terminal frame 3 is aligned with the conductive pattern 13 and held by the high melting point solder.

Next, a silicone resin or an epoxy resin exhibiting low residual stress strain or a synthetic resin thereof is applied to the surface of the small coil element to form a protective film 4 (if the stress strain due to the exterior of the small coil element does not cause a problem). It may be omitted).

A part of the standoff portion 33 of the lead terminal piece 32 is exposed, and as shown in FIG. 1 (c), it is applied by dip coating or sealing with epoxy resin and resin solution or the like to form the exterior 5. After that, as shown by the one-dot chain line in the figure, by cutting the lead terminal piece 32 from the main frame 31 leaving the required length, a small coil having a plurality of external lead-out terminals is completed.

When supplied as taping parts, it becomes possible to supply the small coils as a series of parts which are attached at a predetermined interval with a dedicated machine.

(Effect of the invention) As described above, according to the present invention, since the lead terminal piece serving as the external lead terminal directly holds the small coil element,
Can be easily connected and can be firmly held. In addition, since the end of the lead wire as the winding material of the small coil element is connected to the conductive pattern at a predetermined position in advance, it is easy to handle, and the connection with the lead terminal piece is
No unnecessary external force is applied to the terminal lead, and there is no concern about bending, breaking, or damage of the lead terminal piece.

Further, since the lead terminal pieces are led out from one side in the same plane, they can be easily supplied as taping parts, and when mounted on a circuit board of an electronic device, automation by an automatic inserter becomes easy.

Therefore, it is possible to manufacture a small coil that is easy to handle, inexpensive, and excellent in automatic mounting.

[Brief description of drawings]

FIG. 1 shows a part of the lead terminal frame. (A) shows a state after molding, (b) shows a state in which a small coil element is assembled, (c).
Shows after the exterior. FIG. 2 is a perspective view of a small coil element used in the present invention. FIG. 3 is a sectional view of the lead terminal frame. 1: Small coil element, 3: Lead terminal frame, 4: Protective film, 5:
Exterior, 11: Square core, 12: Holding part, 13: Circuit pattern, 31: Main frame, 32: Lead terminal piece, 33: Standoff part, 34: Holding part.

Claims (1)

[Claims] 1. A lead terminal made of a conductive metal plate comprising a strip-shaped main frame and a lead terminal piece group of a predetermined length, which is provided in a comb shape at intervals in the lengthwise direction of the main frame and has a holding portion at its tip. A frame and a rectangular core made of a high-permeability magnetic material are provided with windings, and one end of the core has a held portion held by the holding portion of the lead terminal piece. And a small coil element in which a conductive pattern is generated. In the small coil element, the end of the winding is wired on the conductive pattern, and the held portion is the holding portion of the lead terminal piece. After being soldered and connected in a sandwiched state, it is protected by an electrically insulating resin or wax protective film that exhibits low residual stress strain characteristics, and is further coated with an electrically insulating resin and resin solution. Features Method of manufacturing a small coil.