JPH08306552A - Flat coil device - Google Patents

Abstract

PURPOSE: To prevent a location slippage, etc., of an inside electrode (connection terminal) when manufacturing in a flat coil. CONSTITUTION: With the use of a metal conductor 5 as a winding core, a copper foil 2 coated with an insulating material 6 on one side or both sides is wound. A copper foil exposing part 2a has beforehand been provided in a part of innermost side of the copper foil 2, and conductive paste agent 8 is applied to a portion of the corresponding metal conductor 5a, and an inside coil is conductively connected to the metal conductor 5a by making use of winding pressure when winding a coil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin coil device. More specifically, the present invention relates to a thin coil device having a structure suitable for mounting on a substrate.

[0002]

2. Description of the Related Art As shown in FIG. 4, a large number of thin coils 1 are used for a stator coil of a small 8 mm VTR motor.
The ones in which 1, ..., 1 are densely arranged in an annular shape are used. As the thin coil 1, in order to increase the space factor,
A thin coil obtained by slicing a conductive foil film wound body having a substantially triangular shape is used. The thin coils are held in the recesses 12 of the substrate 11 provided with the coil connection frame circuit 13, and are connected to each other using the corresponding connection terminals 14 of the coil connection frame 13.

The thin coil 1 has, for example, as shown in FIG. 5, 5 .mu.m or more with one surface coated with an insulating material (not shown).
A foil film of a conductive material having a thickness of about 30 μm, for example, a copper foil 2 is applied with an adhesive (not shown) and wound in a substantially triangular shape to be solidified. The surface connecting the corners of the coil innermost layer of the coil 1 is formed of a substantially flat surface, and the surface corresponding to the base of the triangle is formed of a curved surface having a large radius of curvature corresponding to the outer diameter of the motor. Has been done. The thin coil 1 has a terminal formed by removing the insulating material layer on the corners of the outermost layer of copper foil and the surface of the innermost layer of copper foil hatched. Partial / exposed electrodes 3 and 4 are formed.

As shown in FIG. 6, for example, this thin coil 1 has a substantially triangular shape obtained by winding a copper foil 2 having at least one surface coated with an insulating material 6 and an adhesive 7 around a winding jig 5. It is obtained by cutting a rod-shaped copper foil roll into slices. The core jig 5 is composed of a split mold, and the adhesive 7
After the rod-shaped wound body of the copper foil 2 is hardened by hardening, the metal foil is decomposed and taken out. Then, after being sliced to a predetermined thickness using a wire saw or the like, burrs and the like on the cut surface are removed by etching or the like to obtain the thin coil 1 as shown in FIG.

[0005]

In order to mount the above thin coil on a substrate or the like, conventionally, because of the above-described structure, the insulating material is peeled off only on the side surface of the coil for solder connection. However, in this case, in the manufacturing process of the thin coil, the inner electrode portion 4 of the coil 1 had to be stripped of a predetermined portion of the insulating material before winding. Particularly in the case of a micro coil, the insulating material cannot be peeled off after winding. When such peeling is further performed, in the thin coil having the conventional structure, the position of the predetermined electrode portion of the coil is largely displaced due to the extension due to the tension during winding of the coil, the deformation of the inside portion of the coil during the slicing, or the fraying. , The positional deviation from the electrode portion of the mounting board occurs. As a result, there is a problem that the electrical connection between the coil and the substrate is not performed well.

An object of the present invention is to improve the above-mentioned drawbacks of the prior art by providing a thin coil device having a structure suitable for mounting on a substrate or the like.

[0007]

To achieve the above object, a first invention is a thin coil device which is conductively connected to a terminal of a substrate holding a thin coil formed by winding a conductive foil. A metal conductor is used as a winding core for winding the foil, and the conductive foil and the metal conductor positioned on the innermost circumference wound around the metal conductor are conductively connected, and the metal conductor is connected to the substrate. The point is that it is used as a connection terminal of.

A second invention is based on the first invention and is characterized in that a hole for conductive connection to the substrate is formed in the metal conductor.

In a third aspect based on the first or second aspect, a conductive paste agent is applied to the outer periphery of the metal conductor, and the conductive paste agent causes the innermost conductive foil and the metal conductor to separate from each other. The gist is that they are electrically connected.

[0010]

In the thin coil device of the first invention, a conductive foil is wound around a metal conductor as a winding core, and the metal conductor serves as an inner electrode portion (connection terminal) and is connected to the substrate. Therefore, the displacement of the electrode portion is prevented and the connection with the substrate is facilitated.

In the thin coil device of the second invention, the hole of the metal conductor is used for conductive connection to the substrate.

In the thin coil device of the third invention, the innermost conductive foil and the metal conductor are connected by the conductive paste agent applied to the conductor.

[0013]

Embodiments of the present invention shown in the drawings will be described below.
1 and 2 show an embodiment of a thin coil device according to the present invention, in which the same reference numerals as those in FIGS. 4 to 6 represent the same or similar members, and in particular, a metal conductor 5a is used as a winding core and preferably the metal is used. The conductor 5a is characterized in that a hole 5b is formed at a substantially central portion thereof. That is, a coil is formed by winding a conductive foil 1, for example, a copper foil 2 having one surface or both surfaces coated with an insulating material 6 and an adhesive 7 around a metal conductor 5a as a core. In this case, the copper foil 2 located at the innermost circumference of the coil is partially exposed in advance to be formed in the copper foil exposed portion 2a, and the conductive paste agent 8 is previously applied to the corresponding portion 5c of the metal conductor 5a. The metal conductor 5a and the innermost copper foil 1 are conductively connected to each other by utilizing the tightening pressure when the copper foil is wound.

Note that FIG. 1A is a partially enlarged copy showing the conductive connection portion, and in FIG. 2, the left portion 2b of the copper foil exposed portion 2a may be left with a part of insulating material as shown in the figure. Alternatively, the copper foil may be entirely exposed, and the adhesive 7 is provided on the entire upper surface of the insulating material 6 instead of the line 1 shown in the figure. Further, the tip of the copper foil 1 forming the coil may be fixed with an adhesive agent 7, or a groove may be formed in the metal conductor 5a and the groove may be hooked in this groove to be stopped. The coil is wound by a predetermined number of patterns, and then the metal conductor 5a as the winding core and the coil are integrally cut to a predetermined thickness by slicing. The core integrated coil thus obtained can be used as an electrode (connection terminal) on the entire inner side thereof, so that the conductive connection can be made without considering the positional deviation from the substrate electrode portion.

Next, the hole 5b of the metal conductor 5a can be used for the conductive connection. For example, cream solder is applied to a circuit board, the coil is placed on the circuit board, heated and solder-connected, and used as a hole for solder escape in that case.

Alternatively, as shown in FIG. 3, the hole 5b is used as an insertion hole of the soldering nozzle 11, and the metal conductor 5a and the circuit board 10 are conductively connected from the nozzle 11 by the cream solder 9. In this case, the side surface on the circuit board side is coated with an insulating agent, and the circuit board may be a flexible circuit board.

[0017]

As is apparent from the above description, according to the present invention, the following excellent practical effects can be obtained as a thin coil. (I) The coil inner electrode portion (connection terminal) is not displaced during the manufacturing process, and wiring failure can be prevented. (Ii) Since the coil is integrated with the core, there is no need to remove the core after winding, and the work efficiency is improved. (Iii) Particularly, the winding work of the minute coil becomes extremely easy. In the conventional structure, the coil ends cannot be locked, and it is difficult to wind the minute coil. Therefore, this effect of the present invention is extremely effective in practice. (Iv) The coil can be prevented from being deformed in the slicing process. Conventionally, the largest defect factors were insufficient strength due to wax filling, large deformation due to generation of voids, loosening of the inner coil, etc., but they were basically eliminated by the present invention. (V) Conductive connection with the substrate is easy and reliability is improved.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a process of manufacturing the coil of the above embodiment.

FIG. 3 is an explanatory view showing an outline of a conductive connection method for a thin coil of the present invention.

FIG. 4 is a diagram showing a stator coil of a small motor,
(A) is a plan view and (B) is a sectional view.

FIG. 5 is a plan view illustrating a conventional thin coil.

FIG. 6 is a perspective view showing the coil manufacturing process of FIG. 5;

[Explanation of symbols]

 1 Thin coil 2 Copper foil 5a Metal conductor 5b Hole 6 Insulation material 7 Adhesive agent 8 Conductive paste agent 9 Cream solder

Claims (3)

[Claims] 1. A thin coil device, which is conductively connected to a terminal of a substrate that holds a thin coil formed by winding a conductive foil, wherein a metal conductor is used as a winding core for winding the conductive foil, A thin coil device characterized in that the conductive foil located on the innermost circumference wound around a metal conductor is conductively connected to the metal conductor, and the metal conductor is used as a connection terminal to the substrate. 2. The thin coil device according to claim 1, wherein a hole for conductive connection to the substrate is formed in the metal conductor. 3. A conductive paste agent is applied to the outer circumference of the metal conductor, and the conductive foil at the innermost circumference is conductively connected to the metal conductor by the conductive paste agent. 2. The thin coil device according to 2.