JPH0522369B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel method for manufacturing a rotary transformer. In detail, we will introduce a new rotary transformer that reduces the cost of rotary transformers by reducing the number of man-hours required to manufacture them, and also reduces the size of rotary transformers and improves their performance by improving dimensional accuracy. The present invention aims to provide a method for manufacturing tarans.

Background Art and Problems Therewith For example, in a magnetic recording/reproducing device, a rotary transformer is used to mutually transmit signals between a rotating part and a fixed part.

FIG. 1 shows an example of such a rotary transformer. A pair of annular magnetic cores a, a' are opposed to each other through a small gap, and each magnetic core a,
Annular winding grooves b, b' and c, c' are formed on the opposite surface of a', and coils d, d' and e and e' are inserted. Note that f, f' are short rings provided between the winding grooves b, b' and c, c'.

The annular magnetic cores a and a′ configured as described above are mutually rotatable, and the coil d and
Signals are mutually transmitted between e and e' and between e and e'.

By the way, when manufacturing a rotary transformer as described above, conventionally, conductive wires of appropriate diameters are wound to form coils d, d', e, and e', and these are placed in winding grooves b, b. ′, c, and c′. However, the coils d,
Winding d', e, and e' and inserting them into the specified positions and depths requires extremely precise machining and assembly techniques, and as a result, the cost of rotary transformers is extremely high. It had become a thing.

Also, when forming coils d, d' and e, e', the conductors may partially overlap, so the winding grooves b, b' and c, c' should be made deeper by that amount. It is necessary to form. for example,
When the wire diameter of the conductor is 0.15 mm, the winding grooves b, b' and c,
The depth of c′ needs to be 0.3mm. Then, the distance between opposing winding grooves b and b' and c and c' increases by the above-mentioned extra depth, and there is a problem that direct signal transmission efficiency between the coils decreases. In order to compensate for this loss, it is necessary to increase the area where the magnetic cores face each other, which hinders miniaturization.

Purpose of the Invention The present invention has been made in view of the problems that existed in the conventional manufacturing method of rotary transformers.The present invention aims to reduce the cost of rotary transformers by reducing the number of man-hours for manufacturing rotary transformers. It is an object of the present invention to provide a novel method for manufacturing a rotary transformer that can reduce the size of the rotary transformer and improve its performance by improving accuracy.

Summary of the Invention The method for manufacturing a rotary transformer of the present invention has been accomplished in order to achieve the above-mentioned object, in which a resist mask is formed on the plating base surface made of a conductive material excluding the coil pattern portion, and then the coil pattern is Conductor plating is applied to the part to form a coil,
The present invention is characterized in that the coil is adhesively fixed in a winding groove formed in the magnetic core, and then the plating base is removed to transfer the coil to the magnetic core.

EXAMPLES The details of the method for manufacturing the rotary transformer of the present invention will be described below with reference to illustrated examples.

Example 1 A rotary transformer includes a pair of magnetic cores, but their shapes are substantially the same, and the manufacturing procedure is also the same, so only one magnetic core will be described.

In the figure, reference numeral 1 denotes an annular ferrite core, and two winding grooves 2 and 3 are formed in an annular shape on one surface, and a separation groove 4 is formed at a position between the winding grooves 2 and 3. is formed. Numerals 5 and 6 are coil lead extraction holes formed close to the winding grooves 2 and 3, respectively.

Reference numeral 7 denotes a plating base made of a conductive material such as stainless steel.
Two coils 8, 9 and a shot ring 10 are formed by plating, and the coils 8, 9 and shot ring 10 formed by plating are adhesively transferred into each groove 2, 3, and 4 of the ferrite core 1. In addition, in the plating process, the lead wires 11, 11 and 12, 12 of each coil 8, 9 are also formed, and before the above bonding process, they are raised from the plating base 7 and then inserted into the extraction holes 5, 6. Insert it.

Next, the manufacturing procedure will be explained in more detail with reference to FIG. In addition, in FIG. 5, a part of the ferrite core 1, coil 8, plating base 7, etc. is shown in an enlarged manner.

A photosensitive resist film 13 is attached to the entire surface of the plating substrate 7 (see FIG. 5A). At this time,
Before pasting the photosensitive resist film 13, the entire surface of the plating base 7 is plated with chrome, etc.
A treatment may be applied to facilitate the removal of the plating. It should be noted that it is preferable to use the photosensitive resist film 13 to form the resist mask because the film thickness of the resist mask can be made uniform and a relatively thick film can be obtained. It is not necessary to use only the same type of photoresist agent, and other types of photosensitive resist agents may be used.

Next, the photosensitive resist film 13 is exposed and developed to remove portions of the photosensitive resist film 13 where the coils 8, 9 and the shot ring 10 are to be formed, thereby forming a so-called resist mask 14 (see FIG. 5B). Note that the areas to be exposed to light differ depending on whether the photosensitive resist film 13 is a negative type or a positive type. The part that will become the shot ring is exposed to light.

Conductor plating, for example copper plating, is applied to the plating base 7 on which the resist mask 14 as described above is formed. As a means for applying plating, for example, the plating substrate 7 is made a cathode and pattern portions 8', 9', and 10' (only 8' is shown) are deposited on copper by electroplating means. In this way, a conductor such as copper in the pattern portions 8', 9', and 10' drawn by the resist mask 14 is deposited.
Coils 8, 9 and shot rings 10 are formed on plating substrate 7 (see Figure 5C).

Winding grooves 2 and 3 and separation groove 4 of ferrite core 1
(Only the winding groove 2 is shown in FIG. 5.) An appropriate amount of adhesive 15 is applied inside (see FIG. 5D).

Then, the coils 8 and 9 formed on the plating base 7 and the shot ring 10 are inserted into the grooves 2, 3 and 4 of the ferrite core 1 while being aligned. Then, each coil 8, 9 and shot ring 10 are adhesively fixed to the ferrite core 1 by the adhesive 15 applied in each groove 2, 3, and 4 (see FIG. 5E).

In this case, it is possible to arbitrarily select whether to remove the resist mask 14 from the plating base 7 in advance or to transfer it to the ferrite core 1 together with the coil etc. while leaving the resist mask 14 as an insulating layer. It doesn't matter.

Finally, when the coils 8, 9 and the shot ring 10 are securely bonded and fixed in the winding grooves 2, 3 and the separation groove 4 of the ferrite core 1, the plating base 7 is removed. The shot ring 10 is peeled off from the plating base 7 (see FIG. 5F).

As explained above, according to the method of the present invention, since the coils 8 and 9 are formed by plating means, their dimensional accuracy is extremely good, manufacturing variations are reduced, and the ferrite core 1
The alignment with the respective grooves 2 and 3 is also achieved with extremely high precision. Therefore, the coils 8, 9 and the winding groove 2,
The dimensional relationship between the coils 8 and 3 can be precisely defined in advance, and the planes of the coils 8 and 9 and the ferrite core 1 can be made to coincide (see FIG. 5 E and F). The efficiency of signal transmission in the coil section can be improved, and this
This makes it possible to reduce the opposing area between the pair of ferrite cores, contributing to downsizing of the rotary transformer.

In addition, since the coils 8 and 9 are formed by plating, not only is the coil forming process extremely easy, but even if there are multiple coils, the number of forming steps is hardly increased, so it is possible to manufacture a multi-channel rotary transformer. This has the advantage that the effect of cost reduction is significantly greater.

Embodiment 2 Although the above embodiment has been described using as an example the manufacture of a rotary transformer using a disc-shaped magnetic core, the method of the present invention can also be applied to the manufacture of a cylindrical rotary transformer.

In particular, winding a coil around the inner peripheral surface of a cylindrical magnetic core has conventionally been considered an extremely difficult task, but according to the present invention, a cylindrical rotary transformer can be manufactured extremely easily.

16 is an annular ferrite core, and an annular notched recess 17 is formed on the inner peripheral edge of the upper surface thereof. Notch recess 1 of such ferrite core 16
7, the coil 18 formed using the plating means as described above is adhesively fixed by the procedure shown in FIG.

Reference numeral 19 designates a ferrite core which is also annular and has an annular notched recess 20 formed in the inner peripheral edge of its upper surface, into which a coil 21 formed by plating means is adhesively fixed.

Therefore, if the ferrite core 19 is superimposed on the ferrite core 16 formed in this way and fixed to each other by adhesive or the like, and then the annular ferrite plate 22 of the same shape is superposed and fixed on top of the ferrite core 19, A cylindrical rotary transformer member having coils 18 and 21 attached to its inner peripheral surface is formed.

Although not shown in the drawings, the rotary transformer member paired with this cylindrical rotary transformer member has coils paired with the coils 18 and 21 formed on the outer peripheral surface of the cylindrical body. It can be formed by laminating and bonding a coil having a cutout recess in the cutout recess and adhesively fixing a coil formed by plating means in the cutout recess.

As described above, according to the method for manufacturing a rotary transformer of the present invention, a cylindrical rotary transformer can be manufactured very easily and at low cost, and a cylindrical rotary transformer with good precision and high efficiency can be manufactured. I can do it.

Effects of the Invention As is clear from the above description, the method for manufacturing the rotary transformer of the present invention involves forming a resist mask on the plating base surface made of a conductive material excluding the coil pattern portion, and then forming a resist mask on the coil pattern portion. The present invention is characterized in that a coil is formed by plating, and after the coil is adhesively fixed in a winding groove formed in a magnetic core, the plating base is removed to transfer the coil to the magnetic core.

Therefore, according to the present invention, it is possible to reduce the cost of the rotary transformer by reducing the number of manufacturing steps for the rotary transformer, and to reduce the size and improve the performance of the rotary transformer by improving the dimensional accuracy. A novel method for manufacturing a rotary transformer can be provided.

In the description of the above embodiments, a ferrite core is used as the magnetic core, but the present invention is not limited to this, and it goes without saying that other suitable magnetic core materials can be used.

[Brief explanation of the drawing]

1 and 2 show an example of a conventional rotary transformer, FIG. 1 is a longitudinal sectional view, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is an example of a magnetic core used in the present invention. FIG. 4 is a perspective view of a state in which a coil is formed on a plating base, FIG. 5 is a partially enlarged sectional view showing an example of a method for manufacturing a rotary transformer of the present invention, and FIGS. 6 and 7 are a perspective view of a coil formed on a plating base. Another example of a rotary transformer manufactured by the method is shown, and the sixth
The figure is an exploded perspective view, and FIG. 7 is a longitudinal sectional view. Explanation of symbols, 1...Magnetic core, 2...Winding groove,
3... Winding groove, 7... Plated base, 8'... Coil pattern, 8... Coil, 9... Coil, 14
...Resist mask, 16...Magnetic core, 17...
... Winding groove, 18 ... Coil, 19 ... Magnetic core,
20... Winding groove, 21... Coil.

Claims (1)

[Claims] 1. Form a resist mask on the surface of a plating base made of a conductive material, excluding the coil pattern portion, then apply conductor plating to the coil pattern portion to form a coil, and insert the coil into the winding groove formed in the magnetic core. A method for manufacturing a rotary transformer, comprising transferring the coil to a magnetic core by removing the plating base after the coil has been adhesively fixed to the magnetic core.