JPH0974037A - Method for manufacturing rotary transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the characteristics of a rotary transformer used, for example, for a video tape recorder. SOLUTION: In a rotary transformer, a ferromagnetic body pattern 8 or a nonmagnetic body pattern 7 is formed on one main surface of a forming body made of ferrite and additives and a conductor pattern 6 made of an electrode material is executed to the total surface of a recessed part between them and then sintered, thus obtaining a rotary transformer with a high transfer effect of an electrical signal and a high magnetic transfer efficiency and then an improved productivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rotary transformer used in electronic equipment such as video tape recorders and digital tape recorders for supplying and extracting electric signals from a rotating body to an external stationary body.

[0002]

2. Description of the Related Art In a rotary transformer, a rotor core on a rotating side (head side) and a stator core on a fixed side (electronic circuit side), on which coils are formed concentrically with a drum shaft of a rotary head, are provided on their coil surfaces ( It has a structure in which a space of about 20 to 80 μm is arranged so that the upper surfaces thereof face each other, and thereby signal transmission between the head and the electronic circuit is performed.

Conventionally, a rotary transformer has a flat ferrite core of a sintered body in which an annular groove is formed, and a flat spiral coil formed by winding a conductor in the annular groove is arranged (Japanese Utility Model Publication No. 62-18013). A film on which a conductor pattern is formed is set in a mold of an injection molding machine, a mixture of sinterable ferrite and a binder is injection molded, and then degreased and fired (JP-A-3-248510) or sintered. A body in which a conductor coil film pattern and a ferromagnetic film are formed on a flat surface of ferrite of the body (Japanese Patent Laid-Open No. 2-2
No. 5106), and an annular groove is formed by printing only on one surface of the ferrite core (JP-A-1-209708).

[0004]

A structure in which an annular groove is formed in a ferrite core of a sintered body and a flat spiral coil formed by winding a conductive wire in the annular groove is arranged is troublesome due to dimensional variation of the fired body. Since post-processing is required and it is also necessary to attach a coil, the manufacturing cost is very high.

Further, since it is necessary to machine the annular groove in advance to a depth of about several hundred μm and a large size so that the winding can be stably inserted into the annular groove, the gap between the coil surface of the stator core and the rotor core is usually large. The magnetic resistance becomes high, the coupling coefficient when the stator core and the rotor core are combined is about 0.95, the total inductance is about 4.5 μH, and the loss is about -3.6 dB, and the electrical signal transmission efficiency is There was a problem that it decreased.

A film on which a conductor pattern is formed is set in a mold of an injection molding machine, a mixture of sinterable ferrite and a binder is injection molded, and then degreased and fired. The mixture of sinterable ferrite and binder also enters between the conductors, and a ferromagnetic material is formed between the conductors, resulting in a decrease in the magnetic flux density between the individual conductors of the conductor pattern in one core. There is a problem in that the efficiency of magnetic transfer with the rotor core is reduced.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a rotary transformer having high electric signal transmission efficiency and magnetic transmission efficiency and excellent productivity.

[0008]

In order to solve the above-mentioned problems, a method of manufacturing a rotary transformer according to the present invention comprises a ferromagnetic body or a non-magnetic body pattern formed on one main surface of a molded body made of ferrite and an additive. Formed and fired after applying the electrode material to the entire concave portion between both patterns, or forming a ferromagnetic material and a non-magnetic material pattern on one main surface of a molded body composed of ferrite and an additive, and further After forming a mask of a predetermined pattern on the above, a recess is formed by sandblasting, and the electrode material is applied to the entire surface of the recess and then baked.
Or on the main surface of the molded body consisting of ferrite and additives,
In this method, an electrode pattern or a ferromagnetic material pattern is formed, a mask having a predetermined pattern is further formed on the electrode pattern or the ferromagnetic material pattern, and then a concave portion is formed by sandblasting, followed by baking.

[0009]

According to the method of manufacturing a rotary transformer of the present invention, a ferromagnetic material or non-magnetic material pattern is formed on one main surface of a molded body composed of ferrite and an additive, and an electrode material is applied to the entire concave portion therebetween. After baking or forming a ferromagnetic and non-magnetic pattern on one main surface of the molded body composed of ferrite and an additive, and further forming a mask of a predetermined pattern on it, the concave portion is formed by sandblasting. Then, the whole surface of the concave portion is coated with an electrode material and then baked, or an electrode pattern or a ferromagnetic material pattern is formed on one main surface of a molded body made of ferrite and an additive, and a predetermined pattern is formed on the electrode pattern or the ferromagnetic material pattern. After the mask is formed, the recesses are formed by sandblasting and then baked, so that the ferrite core and the conductor pattern and ferromagnetic pattern are firmly adhered and bonded. Is not required.

Further, by forming the ferromagnetic material pattern, the non-magnetic material pattern, or the electrode pattern to be lower, the gap between the stator core and the rotor core becomes smaller, the magnetic resistance becomes lower, and the electric signals between the adjacent channels crosstalk. It becomes difficult to reduce the loss, and the transmission efficiency of the electric signal can be improved and the loss can be reduced.
Further, since the electrodes can be formed in the entire recess, the electric resistance value can be reduced, and the magnetic flux can be effectively guided to the ferromagnetic pattern without loss in terms of magnetic circuit.

[0011]

1 is a partially cutaway plan view of an embodiment of a rotary transformer of the present invention, FIG. 2 is a sectional view taken along line AB of FIG. 1, and FIG.
5 is a schematic diagram showing another embodiment of the present invention, and FIG. 6 is a schematic diagram showing a comparative example.

1 and 2, in the rotary transformer of the present invention, the rotor core 31 on the rotating side (head side) and the stator core 1 on the fixed side (electronic circuit side) are concentrically arranged with the drum shaft 20 in parallel. Main surface 3 finished to 10 μm
About 20 to 80 μ so that each of them faces each other.
They are arranged with a space of about m between them, so that signals are transmitted between the head and the electronic circuit. In the stator core 1 on the fixed side, a shaft hole 2 into which the drum shaft 20 is inserted, and a plurality of conductor patterns 6, a ferromagnetic material pattern 8, a non-magnetic material pattern 7, and a short ring 10 are formed on the main surface 3,
A warp prevention layer 11 is formed on the opposite surface 4 and is electrically connected via a lead-out conductor pattern 9 via a through hole 5 and a terminal pin.

Similarly, in the rotor core 31 on the rotating side,
A plurality of conductor patterns 36, a ferromagnetic material pattern 38, a non-magnetic pattern 37 and a short ring 40 are formed on the main surface 33 of the shaft hole 32 for mounting the drum shaft 20, and a warp prevention layer 41 is formed on the opposite surface 34. Formed, through hole 5
It is configured to be electrically connected via a conductor pattern 39 for taking out via a terminal pin or the like.

The ferromagnetic material patterns 8 and 38 are made of a ferrite material, and the same ferrite material as that of the molded body can be used. The non-magnetic patterns 7, 37 are the conductor patterns 6, 3
In order to prevent leakage of magnetic flux since it is formed between the six, it is preferable not to have magnetism (relative permeability), but if the relative permeability is 30 or less, there is no problem in terms of coupling coefficient, and Zn ferrite, A ceramic material such as ZnCu ferrite or Al ₂ O ₃ can also be used.

The conductor patterns 6 and 36 are 850 to 120.
Silver, silver-palladium, silver-platinum, or copper, which can be baked at a low temperature of 0 ° C., is preferable. The mask pattern is preferably made of a soft resin such as butyral resin that does not easily drop off during sandblasting. Even if the mask pattern remains after sandblasting, it disappears after firing, and there is no problem. Even in the case of a mask pattern such as ceramic powder or a composite thereof with a resin, if the composition is such that the magnetic powder on the ferromagnetic pattern and the non-magnetic powder on the non-magnetic pattern remain after firing, there is a particular problem. There is no.

The thickness of the ferromagnetic material patterns 8, 38, the non-magnetic material patterns 7, 37 and the conductor patterns 6, 36 is several μm.
˜several tens of μm, and the difference in thickness between the conductor patterns 6,36 and the ferromagnetic material patterns 8,38 or the non-magnetic material patterns 7,37 is 0 to tens of μm, the resistance of the conductor is reduced, and the magnetic flux density is increased. In terms of Ferrite material is 850
NiZnCu-based ferrite that can be fired at a low temperature of 1200 ° C. is preferable, but it goes without saying that other ferrite materials are also effective.

Conductor patterns 6, 36 only on the main surface of the molded body
In the case where the ferromagnetic patterns 8 and 38 are formed, the difference in the molding density between the ferrite molded body and the convex pattern or the difference in the firing shrinkage behavior between the conductor patterns 6 and 36 and the ferrite molded body causes a difference in firing density. It warps in the direction or cracks occur. Therefore, by providing the warp prevention layers 11 and 41 on the opposite surface, it is possible to balance and reduce the warp on the surface opposite to the main surface. The warp prevention layers 11 and 41 may be patterned on the entire opposite surface or partially. Alternatively, the warp prevention layer may be formed by forming a concave portion on the opposite surface with a mold or the like so that the opposite surface has a different molding density. As the partial pattern shape of the warp prevention layer, a shape in which only the extraction conductor patterns 9 and 39 are formed in the concave portion, a concentric shape, a non-circular shape, a rib shape, a spiral shape, a radial shape, a linear shape, a polygonal shape, a dot shape, or the like thereof Combination patterns and the like are conceivable, but all are effective, and the warp can be controlled by changing the thickness of the warp prevention layers 11 and 41. The warp prevention layers 11 and 41 on the opposite surface do not have to be a ferromagnetic material such as a ferrite material in terms of magnetic circuit, and a nonmagnetic material, a dielectric material, a resistance material, or the like may be used.

When the height of the conductor patterns 6 and 36 on the main surface is higher than the depth of the recesses on the same surface, the magnetic flux generated from the conductor patterns 6 and 36 easily leaks from the ferromagnetic material patterns 8 and 38 and the coupling coefficient becomes low. In addition, the conductor patterns 6 and 36 react during the repeated firing. Therefore, it is preferable that the height of the conductor patterns 6 and 36 on the main surface is equal to or less than the depth of the recesses on the same surface. Similarly, since the lead-out conductor patterns 9 and 39 on the opposite surface also do not react during the repeated firing, the warp prevention layer 1
It is preferable that the conductor patterns 6 and 36 are formed in the concave portions 1 and 41 and the height of the conductor patterns 6 and 36 is not more than the depth of the concave portions.

Additives for the molded product include organic binders such as binders, plasticizers, lubricants and defoamers, or inorganic binders containing at least the same elements as the elements constituting ferrite. Any thing can be used. Here, the inorganic binder is for preventing shrinkage during sintering of the ferrite, for example, iron powder, zinc powder, nickel powder, copper powder and the like metal oxide powder is oxidatively expanded to shrink during sintering. It can be canceled and the shrinkage rate of the sintered body can be made almost zero, and in the case of only the molded body with no pattern formed on both sides, the warpage during firing is several μ
It can be controlled to m or less.

When the molded body is punched out by a die or the like before firing, if there is a convex pattern portion on the outermost peripheral portion of the main surface, the stress is concentrated on the end face of the outermost peripheral portion at the time of punching, so the pattern is missing. Therefore, it is preferable that the convex portion is formed at least 0.1 mm or more from the outermost periphery.

Specific examples will be described below. (Embodiment 1) FIGS. 3A to 3E show partial cross-sectional schematic views of a core which is a manufacturing process of an embodiment according to the present invention.

Raw material powders having the following main compositions were calcined at 700 ° C. for 3 hours and then pulverized to have an average particle size of 1 μm. NiZnCu-based ferrite calcined powder A, ZnCu ferrite calcined powder Sintered powder B was prepared, slurry A and B were produced by adjusting the slurry concentration while adding additive A (binder, plasticizer, lubricant, defoaming agent).

The compositions of the calcined ferrite powders A and B and the additive A are shown below. Ferrite calcined powder _{A; Fe 2 O 3 49mol%} ZnO 27mol% NiO 13mol% CuO 11mol% --- 100kg ferrite calcined powder _{B; Fe 2 O 3 49mol%} ZnO 45mol% CuO 6mol% --- 100kg additive A -Binder butyral resin --- 140 liters-Plasticizer --- 1.5 kg-Lubricant--4-kg Defoamer --- 1.5 liters This slurry A is thickened using a doctor blade method. A green sheet having a size of 200 μm was produced. A laminate of these green sheets was hot pressed at 120 ° C.
Green sheet 1 shown in (a) with a thickness of 0.95 mm
2 This green sheet 12 is cut into a predetermined size, a through hole 5 having a diameter of 0.3 is formed by a puncher, and the through hole 5 is filled with AgPd paste as shown in FIG. On the surface), the taken-out conductor pattern 9 was formed with AgPd. After that, as shown in FIG. 3C, a magnetic material pattern 8 (pattern width of about 1000 μm, thickness of 40 μm) was screen-printed on one surface (main surface) of the molded body with a ferrite ink having the same composition as the core. , And non-magnetic material pattern 7 on the same surface
(Pattern width of about 100 μm, thickness of 40 μm) was screen-printed with the slurry B in a spiral coil shape. After that, a conductor pattern 6 made of AgPd paste was formed on the entire surface of the recess 13 between the non-magnetic material pattern 7 or the magnetic material pattern 8 by screen printing as shown in FIG. 3D. Thereafter, as shown in FIG. 3 (e), the warp prevention layer 11 is coated with a ferrite ink having the same composition as the core on the entire opposite surface (thickness 15).
After screen-printing on the
It was cut so as to have a disk shape of 5.56 mm and an inner diameter of 4.54 mm.

After degreasing the molded body thus produced,
Sample 1 was obtained by firing in air at 970 ° C. Further, for comparison, a sample in which the warp prevention layer was not formed was also fired, but the warpage was large, and it was necessary to polish the surface after firing.

The electromagnetic conversion characteristics were measured at a gap of 25 μm between the stator core and the rotor core, and the values at 1 MHz are shown.
The results are shown in (Table 1). It can be seen that the electromagnetic conversion characteristics are superior to those of the comparative example.

(Embodiment 2) FIGS. 4 (a) to 4 (g) show partial cross-sectional schematic views of a core which is a manufacturing process of another embodiment according to the present invention.

After calcining the raw material powder blended so that the main composition becomes the following composition at 700 ° C. for 3 hours, prepare ZnCu ferrite calcined powder C pulverized to have an average particle size of 1 μm and add it. Agent A (binder, plasticizer, lubricant,
Slurry C was prepared by adjusting the slurry concentration while adding a defoaming agent). Further, a slurry D for a mask in which an Al ₂ O ₃ powder having an average particle size of 1 μm and a butyral resin were mixed was prepared. Ferrite calcined powder C; Fe ₂ O ₃ 49 mol% ZnO 51 mol% --- 100 kg Additive A; -Binder butyral resin --- 140 liters-Plasticizer --- 1.5 kg-Lubricant ---- 4 kg foams --- for 1.5 liters mask slurry D; · binder butyral resin --- 140 l · Al ₂ O ₃ --- 100kg · plasticizer --- similarly to 1.5kg example 1, the slurry a Using a doctor blade method, a green sheet having a thickness of 200 μm was produced. As shown in FIG. 4 (a), a laminate of these green sheets was hot-pressed at 120 ° C. to obtain a molded body having a thickness of 0.9.
I made a 5mm green sheet 12. This green sheet 12 is cut into a predetermined size, a through hole 5 having a diameter of 0.3 is formed by a puncher, and then, as shown in FIG.
The through hole 5 was filled with Pd paste, and the conductor pattern 9 was formed from AgPd on one surface (opposite surface) of the molded body. Then, as shown in FIG. 4C, the magnetic material pattern 8 (pattern width of about 1000 μm) is formed on one surface (main surface) of the molded product.
m, thickness 30 μm), an annular pattern was screen-printed with a ferrite ink having the same composition as the core, and a non-magnetic material pattern 7 (pattern width of about 1000 μm, thickness 30 μm) was screen-printed on the same surface at other locations. . Then, as shown in FIG. 4D, the magnetic material pattern 8 is formed.
Alternatively, the mask pattern 14 is formed on the non-magnetic material pattern 7.
(Pattern width of about 100 μm, film thickness of 10 μm) was screen-printed with the slurry D for mask. Thereafter, by using a SiO ₂ powder having an average particle diameter of 20 μm, sandblasting was performed to dig a portion other than the mask pattern 14 by about 40 μm or more to form the recess 13 as shown in FIG. 4E. The conductor pattern 6 made of Ag paste is provided in the recess 13.
Was formed by screen printing as shown in FIG.
Then, as shown in FIG. 4 (g), the warp prevention layer 11 was coated with ferrite ink having the same composition as the core on the entire opposite surface (thickness: 15 μm).
m), screen-printed, and then pressed to have an outer diameter of 25.
It was cut into a disc shape having a diameter of 56 mm and an inner diameter of 4.54 mm. The molded body thus produced was degreased and then fired at 900 ° C. in air to obtain Sample 2.

The electromagnetic conversion characteristics were measured with a gap of 25 μm between the stator core and the rotor core, and the values at 1 MHz are shown.
The results are shown in (Table 1). It can be seen that the electromagnetic conversion characteristics are superior to those of the comparative example.

(Embodiment 3) FIGS. 5A to 5F are partial cross-sectional schematic views of a core which is a manufacturing process of still another embodiment according to the present invention.

As in Example 1, raw material powders having the following main composition were calcined at 700 ° C. for 3 hours and then crushed to have an average particle size of 1 μm.
An nCu-based ferrite calcined powder A was prepared, and the slurry concentration was adjusted while adding the additive B (shrinkage inhibitor, binder, plasticizer, lubricant, defoaming agent) to prepare a slurry E.
The composition of additive B is shown below. Ferrite calcined powder A; Fe ₂ O ₃ 49 mol% ZnO 27 mol% NiO 13 mol% CuO 11 mol% --- 100 kg Additive B; -shrinkage inhibitor Fe 65.8 mol% ZnO 18.1 mol% NiO 8.7 mol% CuO 7 .4 mol% ---- 25 kg-Binder butyral resin --- 180 liters-Plasticizer--2 kg-Lubricant--6 kg-Defoamer--2 liters As in Example 1, a shrinkage inhibitor is included. No slurry A,
A 200 μm-thick green sheet was prepared using the doctor blade method. Similarly, a slurry E of the above composition containing a shrinkage inhibitor was prepared by a doctor blade method to prepare a green sheet having a thickness of 200 μm. As shown in FIG. 5 (a), a laminate of the respective green sheets was hot-pressed at 120 ° C. to obtain a molded body having a thickness of 0.95.
I made the green sheet 12 of mm. This green sheet 1
2 is cut into a predetermined size, and a through hole 5 of 0.3φ is formed by a puncher as shown in FIG.
The through hole 5 was filled with d paste, and the conductor pattern 9 was formed from AgPd on one surface (opposite surface) of the molded body. Thereafter, as shown in FIG. 5C, the magnetic material pattern 8 (pattern width of about 1000 μm, on one surface (main surface) of the molded product,
As a thickness of 40 μm), an annular pattern is screen-printed with a ferrite ink having the same composition as the core, and the conductor pattern 6 (pattern width of about 1000 μm, thickness 40
(μm) was screen printed with Ag paste. afterwards,
As shown in FIG. 5D, a mask pattern 14 (pattern width of about 10 is formed on the magnetic material pattern 8 or the conductor pattern 6).
Butyral resin having a thickness of 0 μm and a film thickness of 10 μm) was screen-printed. After that, a portion other than the mask pattern 14 is dug by about 40 μm or more by sandblasting using SiO ₂ powder having an average particle diameter of 20 μm, and FIG.
As shown in FIG. After that, as shown in FIG. 5 (f), a warpage preventing layer 11 was screen-printed with a ferrite ink having the same composition as the core on the entire opposite surface (thickness 15 μm), and then pressed to form an outer diameter of 25.56 mm and an inner diameter of 4.54 mm. It was cut into a disk shape. After degreasing each of the molded bodies produced in this way, they were fired in air at 900 ° C. to obtain Samples 3 and 4.

When the amount of warpage after firing was measured, Sample 3 to which no shrinkage inhibitor was added was 20 μm, and Sample 4 with added shrinkage inhibitor was 3 μm. It can be seen that the non-shrinkage inhibitor is effective in reducing distortion of the rotary transformer. I understand. The electromagnetic conversion characteristics are
The value was measured at 1 MHz with a gap of 25 μm between the stator core and the rotor core. The results are shown in (Table 1).
It can be seen that the electromagnetic conversion characteristics are superior to those of the comparative example.

(Comparative Example) FIGS. 6A to 6C show partial cross-sectional schematic views of a core which is a manufacturing process of a comparative example according to the present invention.

As shown in FIG. 6 (a), the ferrite calcined powder A was subjected to a die press to obtain a disk-shaped compact 15 having a thickness of 2 mm, an outer diameter of 30 mm and an inner diameter of 3 mm at 1 ton / cm ² . After degreasing the molded body 15, the molded body 15 is fired in air at 1000 ° C., and a post-processed sintered body has a thickness of 1.3 mm and an outer diameter of 25.56 mm.
It was made to have a disk shape with an inner diameter of 4.54 mm. On one surface (main surface) of the sintered body thus manufactured, as shown in FIG. 6B, the concave portions 16 (pattern width of about 1000 μm) having an annular pattern are formed.
m, thickness 400 μm) and a through hole 17 of 0.5φ was formed. After that, as shown in FIG. 6C, the adhesive 18 was poured into the recess 16 to form a 0.2φ conductor coil 19 by winding, and the sample 5 was prepared by taking out from the through hole to the opposite surface.

The electromagnetic conversion characteristics were measured at a gap of 25 μm between the stator core and the rotor core, and the values at 1 MHz are shown.
The results are shown in (Table 1). Because of the winding method, the recess depth is deeper (500 μm) than that of the embodiment, and the non-magnetic adhesive portion is located under the winding. Therefore, the electromagnetic conversion characteristics are considered to be inferior to the embodiment.

[0035]

[Table 1]

In the rotary transformer manufacturing method of the present invention, various materials (ferrite powder, binder,
Conductor, ferromagnetic material, material composition of non-magnetic material, particle size distribution, etc.), molding method (molding, green sheet molding, injection molding, green sheet single layer or laminated),
Firing conditions (temperature, time, pressure, atmosphere, etc.), conductor and ferromagnetic material, non-magnetic material molding method (printing, transfer, inkjet, etc.), rotary transformer shape (outer diameter, inner diameter, thickness, gap, conductor pattern, The dimensions of the ferromagnetic pattern, the non-magnetic pattern, the through holes, etc.) are not limited to those in this embodiment.

[0037]

As described above, according to the method of manufacturing a rotary transformer of the present invention, a ferromagnetic material or non-magnetic material pattern is formed on one surface (main surface) of a molded product composed of ferrite and an additive, and a pattern between them is formed. Ferromagnetic material and non-magnetic material patterns are formed on one surface (main surface) of a molded body composed of ferrite and an additive, after firing the electrode material over the entire surface of the groove (concave portion), and then a predetermined pattern is formed thereon. After forming the mask of the pattern of, the recess is formed by sandblasting, the electrode material is applied to the entire surface of the recess and then fired, or the electrode pattern or the strong surface is formed on one surface (main surface) of the molded body composed of ferrite and the additive. A magnetic material pattern is formed, a mask with a predetermined pattern is further formed on the magnetic material pattern, and then a concave portion is formed by sandblasting, followed by baking. Rate is high, it is possible to obtain an excellent rotary transformers in productivity.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing a rotary transformer obtained by an embodiment of a method for manufacturing a rotary transformer of the present invention.

FIG. 2 is a sectional view showing an embodiment of the rotary transformer.

FIG. 3 is a partial sectional schematic view showing a manufacturing process of an embodiment of the rotary transformer of the present invention.

FIG. 4 is a partial sectional schematic view showing a manufacturing process of an embodiment of the rotary transformer of the present invention.

FIG. 5 is a partial sectional schematic view showing a manufacturing process of an embodiment of the rotary transformer of the present invention.

FIG. 6 is a partial cross-sectional schematic view showing a manufacturing process of a comparative example of the rotary transformer of the present invention.

[Explanation of symbols]

 1 Stator core 3,33 Main surface 4,34 Opposite surface 5,35 Through hole 6,36 Conductor pattern 7,37 Non-magnetic material pattern 8,38 Ferromagnetic material pattern 9,39 Extraction conductor pattern 10,40 Short ring 31 Rotor core

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Hashimoto 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. A ferromagnetic or non-magnetic pattern is formed on one main surface of a molded body composed of ferrite and an additive, and an electrode material is applied to the entire concave portions formed between the patterns, followed by firing. The manufacturing method of the rotary transformer obtained by doing. 2. A ferromagnetic material and a non-magnetic material pattern are formed on one main surface of a molded product composed of ferrite and an additive,
After forming a mask of a predetermined pattern on it,
A method of manufacturing a rotary transformer obtained by forming a recess by sandblasting, applying an electrode material to the entire surface of the recess, and then firing the electrode material. 3. An electrode pattern or a ferromagnetic material pattern is formed on one main surface of a molded product made of ferrite and an additive, and a mask having a predetermined pattern is further formed on the electrode pattern or the ferromagnetic material pattern, and then a recess is formed by sandblasting. A method for manufacturing a rotary transformer obtained by post-baking. 4. The rotary transformer according to claim 2, wherein the mask is made of a ceramic or a resin alone or a composite thereof, and is formed by printing or transferring on a ferromagnetic material, a non-magnetic material, or an electrode pattern. Manufacturing method. 5. The method for producing a rotary transformer according to claim 1, wherein the additive is composed of an inorganic material containing at least the same element as the element constituting the ferrite. 6. The method for manufacturing a rotary transformer according to claim 1, wherein a warp prevention layer is formed on the opposite surface of the molded body made of ferrite and the additive. 7. A structure in which a conductor pattern for extraction is formed on the opposite surface, and the conductor pattern for extraction and the conductor pattern on the main surface are energized by a conductive member via a through hole. Method for manufacturing the described rotary transformer. 8. The method of manufacturing a rotary transformer according to claim 1, wherein the height of the conductor pattern on the main surface is not more than the depth of the recess on the same surface.