JPH056422B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for attaching a coil, such as a stator coil of a flat type brushless DC motor, to a wiring board.

BACKGROUND TECHNOLOGY AND PROBLEMS As a brushless DC motor, a plurality of molded coils are arranged flush on a wiring board provided on a stator yoke to form a stator. Some magnets have a structure in which a rotor magnet is magnetized into a plurality of poles in the circumferential direction so as to form an extremely short gap with the coil, and the overall shape is extremely flat and thin.

FIG. 1 shows an example of the structure of a stator of this flat type brushless DC motor, in which 1 is a yoke, and 2 is an insulated wiring board provided on this yoke 1. In FIG. A conductive pattern is formed on the surface of the wiring board 2 in a predetermined shape. Then, on this wiring board 2, in this example, six molded coils 3 are arranged as shown in the figure.
The coils are provided on the same plane so as not to overlap each other, and connections between the coils are made by conductive patterns. The shaped coil 3 is formed by winding a conducting wire 4 as shown in FIG. 2 into a predetermined shape using a winding machine. That is, the conductive wire 4 is a self-bonding conductor consisting of a core wire 5 made of copper or the like, an insulating coating 6 such as enamel, and an adhesive coating 7 further applied thereon. While the skin covering 7 is melted by a solvent or heating, it is formed and wound by a winding machine into, for example, a substantially triangular shape as shown in the figure, and after winding is completed, the adhesive is solidified.
A shaped coil is formed.

The adhesive coating 7 and the insulation coating 6 are peeled off at a predetermined length at the beginning and end of the formed coil 3, as indicated by diagonal lines in FIG. 3, and the core material 5 is exposed. coil leads 8 and 9
It is said that Then, a portion 10 of the conductive pattern of the wiring board 2 to be connected to the leads 8 and 9.
and 11 are aligned and connected by soldering when the coil is arranged on the wiring board 2, as shown in FIG. Along with this connection, the coil 3 is bonded and fixed to the wiring board.

The process of providing the above-described coil 3 on the wiring board 2 will be explained in order below.

First, as shown in FIG.
A temporary adhesive 12 for positioning is applied or printed at a predetermined position on the substrate 2.

Next, cream solder 1 is used to solder the coil leads 8 and 9 of each coil 3 to the conductors 10 and 11.
3 is coated or printed on the conductors 10 and 11.

Next, each coil 3 is mounted in a predetermined position.
At this time, the coil 3 is fixed by the temporary adhesive 12, and the coil 3 is prevented from shifting during the next soldering process.

Once each coil 3 is mounted, heat it. Then, the cream solder melts and the coil leads 8 and 9 and the conductors 10 and 11 are joined together.

After this soldering step is completed, the coil 3 is permanently bonded to the substrate 2. At this time, the main adhesive 14 is filled into the winding hole of each molded coil 3 and bonded, as shown in FIG. 1, for example. Note that the adhesive is selected depending on the heating conditions during soldering, and may differ between temporary bonding and actual bonding.

As described above, a plurality of coils 3 are fixed on the wiring board 2 and each lead is attached to a predetermined conductive pattern by soldering.As can be seen from the above explanation, the installation of the coil 3 is There are relatively many steps involved, and as a result, the coil installation is time-consuming and costs are high.

OBJECT OF THE INVENTION The present invention aims to provide a coil mounting method that alleviates the above-mentioned drawbacks.

SUMMARY OF THE INVENTION The present invention achieves the above object by omitting the conventional main bonding process, and the position where the coil is fixed on the wiring board is provided with a circumferential shape that follows the circumferential shape of the coil. A conductor is provided at a plurality of different positions within the shaped area, a coil lead is provided at a winding start end or a winding end of the coil, and at least one of the winding start end or winding end is located at the plurality of conductor positions. The corresponding parts of the coating have been peeled off, and the coil leads at the winding start end and winding end of the coil are soldered to a predetermined conductive pattern on the wiring board, and the peeled part of the coil's coating is attached to the plurality of conductors. The coil is fixed on the wiring board by soldering.

In addition to soldering the coil lead and the conductor on the wiring board, the peeled part of the skin along the circumference of the coil and the corresponding conductor part on the wiring board are soldered.
The coil is fixed at the same time as the coil wiring is connected, and the conventional coil bonding process is eliminated.

Embodiment Hereinafter, the present invention will be explained with reference to an embodiment of the present invention.

In the example shown in FIG. 5, a relatively short portion of the winding start end of the coil 3 is peeled off to form one coil lead 8 as in the conventional method, but the winding end end is peeled off from the coil lead 8. Also peel off the long part. That is, in this example, as shown in FIG.
The adhesive 7 and insulator 6 are peeled off. Then, approximately one turn of the end portion of the coil 3 is not only the coil lead 9 portion, but also the outer peripheral portion along the coil shape as an exposed portion 20 in which the core wire 5 is exposed.

On the other hand, on the wiring board 2, in addition to conductors 10 and 11 to which the coil leads 8 and 9 are connected, a conductor pattern 21 is formed extending from the conductor 11 and corresponding to the exposed core portion 20 of the coil 3. be done.

Then, as shown in Fig. 1, when fixing the coil 3 on the wiring board 2, a temporary adhesive for temporarily fixing the coil 3 is applied or printed on the wiring board 2, and then conductors 10 and 1
1. Furthermore, cream solder is applied or printed on the conductor pattern 21.

Next, coil leads 8 and 9 and conductors 10 and 1
1 and the conductor pattern 21.
The coil 3 is mounted on the substrate 2 by aligning the exposed core portion 20 of the coil 3 with the position shown in FIG.

Then heat it. Then, coil leads 8 and 9
are soldered to the conductors 10 and 11, and the exposed core portion 20 is soldered to the conductive pattern.

With the above steps, the process is completed. That is, the process of main bonding using an adhesive is eliminated. This is because the core wire exposed portion 20 on the outer periphery of the coil is bonded to the conductor pattern 21, which serves to adhesively fix the coil 3 to the substrate 2.

FIG. 6 shows another example of the present invention. In this example, instead of peeling off and exposing a portion of the outer periphery of the coil 3 that is a little less than one turn, the coil 3 is peeled off intermittently to form a plurality of exposed portions 22. ₁ , 22 ₂ ... 22 ₆ , on the other hand,
Correspondingly, the conductor pattern on the substrate 2 also has a fifth
A plurality of conductors 23 within the area of the conductor 21 in the illustrated example.
₁ , 23 ₂ ...23 ₆ are formed.

Also in this example, the coil leads 8 and 9 of the coil 3, the conductors 10 and 11, and the core wire exposed portion 22
₁ , 22 ₂ ...22 ₆ and conductors 23 ₁ , 23 ₂ on the board 2 side
...23 ₆ are aligned, the coil is mounted on the substrate 2, heated and soldered, and the coil leads 8, 9 and the conductors 10, 11 are electrically connected and at the same time the coil 3 is bonded to the substrate 2. It will be fixed.

Note that a formed coil having a core exposed portion 20 as shown in FIG. 5 is connected to a plurality of conductors 23 ₁ to 23 as shown in FIG.
The same effect can be obtained by mounting and soldering the coil shown in FIG. 6 on the wiring board 2 shown in FIG _. 5. The same applies.

Further, a core wire exposed portion similar to the above is formed in the one-turn conductor portion having the innermost portion where the coil lead 8 is formed, and a conductor is also formed at a position corresponding to the wiring board. This innermost peripheral portion can also be used for adhesive fixation.

By the way, in order to make a formed coil by winding the coil 3 in an aligned manner so that the coil leads 8 and 9 are led out to the same end face 24 side, the conducting wire 4 is wound from the inner circumferential side as shown by the arrow in FIG. As it is wound, the innermost layer is the first layer and the even-numbered layers are the outermost layers. Then, as is clear from FIG. 7, the distance from the coil end face 24 differs between the odd-numbered layers and the even-numbered layers by 1/2 of the diameter d of the conducting wire 4. For this reason, cream solder is applied or printed on the conductor of the board 2, and the coil leads 8, 9 and the core wire exposed portions 20, 2 are coated or printed.
When joining 2 ₁ , 22 ₂ ... 22 ₆ , if you apply cream solder, etc., the inner conductor 10 and coil lead 8 can be sufficiently soldered, but the solder on the outer periphery is too thin. It will not be joined at all.
Therefore, when applying a thick layer of cream solder to ensure sufficient soldering on the outer periphery, there was too much solder on the 8 parts of the coil lead inside the coil, resulting in solder balls as shown in Figure 8. There are some inconveniences. It is also possible to apply cream solder thinly on the inner periphery and thickly on the outer periphery, but this would require different heating conditions for the inner and outer peripheries, leading to instability and a risk of poor conductivity.

Therefore, in this example, as shown in FIG. 9, two more turns of conductive wire are wound around the outermost portion. Of these two turns of conductor wire, one turn 4 on the end face 24 side
1 is for forming the coil lead 9 and core wire exposed part, and the other 1 turn 42 is for forming the coil lead 9 and core wire exposed part.
This is for holding the turn 41.

In this way, the innermost one turn 43 and the outermost one turn 41 come into contact with the end surface 24 and have the same height.

Therefore, as shown with diagonal lines in FIG. 10, the innermost and outermost conductor wires are stripped of their sheaths to form the coil leads 8 and 9 as well as the exposed core portions 20 and 2.
When 2 ₁ to 22 ₆ are formed, the gaps between them and the substrate 2 are the same on the innermost and outermost peripheries, so by applying or printing cream solder to a uniform thickness on the substrate, As shown in FIG. 11, soldering can be performed reliably without producing solder balls.

Note that this invention is characterized by the method of installing the coil, so it is not limited to the case of manufacturing a stator for a brushless DC motor, but is applicable to all cases where coils are arranged on a wiring board, such as wiring of solenoid coils, relay coils, etc. Of course, the present invention can also be applied to a method for mounting a board.

Effects of the Invention As described above, in this invention, the coil can be adhesively fixed to the wiring board by soldering at the same time as the coil lead is bonded to the conductor pattern on the wiring board, so there is no need to inject adhesive as in the conventional method. This eliminates the need for a solidification process and automates the process of attaching such a coil to a wiring board.
The automation process can be simplified, improving work efficiency and reducing costs.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of the structure of a stator of a brushless DC motor, Fig. 2 is a diagram showing an example of a conducting wire for forming a formed coil, and Figs.
A diagram for explaining the manufacturing process of the stator shown in the example, FIG. 5 is a diagram for explaining an example of the method of this invention,
FIG. 6 is a diagram for explaining another example, and FIGS. 7 to 11 are diagrams for explaining preferred winding states of the shaped coil used in the present invention. 2 is a wiring board, 3 is a molded coil, 4 is a covered conductor wire, 8 and 9 are coil leads, 10 and 11 are conductors to be joined to these leads, 20, 22 ₁ to 2
2 ₆ is the core wire exposed part where the skin cover has been peeled off, 21, 23 _1
-236 are conductors provided correspondingly on the wiring board.

Claims (1)

[Scope of Claims] 1. A coil is formed by winding conductive wires having insulation coatings in close contact with each other a predetermined number of times, and a pair of electrodes of the coil are provided on the mounting surface of the coil, and one electrode is provided on the mounting surface of the coil. In a method for attaching a coil to a wiring board, in which a coil is arranged on the inner circumferential side and the other electrode is arranged on the outer circumferential side, on a wiring board provided with a conductive pattern to which the electrode is connected, the outer circumferential shape of the coil is fixed. Alternatively, a conductor pattern along a circumferential shape is provided on the wiring board separately from the conductive pattern, and the insulating coating of the coil is peeled off at a portion where the conductor pattern along the outer circumference or the circumference comes into contact. Wiring in which the core wire is exposed, the pair of electrodes and the conductive pattern are soldered, and the exposed core wire portion of the coil is soldered to the conductor pattern to fix the coil on the wiring board. How to attach the coil to the board.