JPH01209708A - Rotary transformer - Google Patents

Abstract

PURPOSE:To enhance automation and mass productivity and to decrease costs, by printing paste state ferrite on a planar core, forming annular grooves, and forming coils in said annular grooves. CONSTITUTION:Paste state ferrite is printed on one surface of a disk shaped ferrite core 101, and an annular parts 102 are formed. Copper is printed between the annular parts 102, and coils 103 are formed. Copper is printed on the rear surface of the core, and connected electrodes 104 are formed. The coils 103 and the connecting electrodes 104 are conducted by way of through holes 105 formed in the core 101. Since the annular grooves in which the coils are formed are formed by printing the paste state ferrite, the depth of each annular groove can be set at about 20-30 microns extremely easily. Therefore, a rotary transformer wherein the plated coils or the printed coils are used can be manufactured readily.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a rotary transformer used in a video tape recorder, etc., which transmits and receives signals between a rotating magnetic head and a stationary main body circuit. .

(Prior Art) Conventionally, various types of rotary transformers have been proposed. For example, as described in Japanese Unexamined Patent Publication No. 62-219506, various rotary transformers in which coils are formed by plating have been proposed. Compared to a rotary transformer using a coil made by winding a wire, this rotary transformer using a plated coil is extremely easy to insert and adhere into the groove of the core after one coil winding, reducing assembly man-hours. and can be automated.

It is suitable for mass production.

FIG. 4 shows a cross-sectional view of an example of a rotary transformer using a plated coil. In this rotary transformer using a plated coil, the plated coil is inserted into an annular groove 402 formed on one surface of a disk-shaped ferrite core 401. 403 was formed, and the leads of this coil 403 were drawn out to the back surface 404 of the core 401 through a through hole formed in the core, and were made conductive to a wiring conductor pattern 405 formed on the back surface 404.

(Problems to be solved by the invention) In rotary transformers using conventional plated coils,
The groove depth of the annular groove in which the plated coil is formed is 20 to 50 mm.
It was a very shallow groove, with a diameter of micron. In order to create such shallow grooves uniformly in a ferrite core, a flat core is created.

After polishing the surface, it was necessary to form it by processing.

In addition, a method has also been proposed in which an annular core is bonded onto a flat core to form an annular groove (Japanese Patent Application Laid-open No. 62-2010 mentioned above).
19506), for example, it is impossible to actually produce an annular core with a thickness of 50 microns, and furthermore, it is impossible to bond these annular cores concentrically with high precision. , is extremely difficult. Of course, the method of forming the grooves using a mold when molding the core cannot achieve this because the deformation during firing is large.

Therefore, conventionally, the annular groove in which the coil of a rotary transformer using a plated coil is formed is formed by processing the core. However, in order to form the annular groove in the core with high precision, advanced processing technology is required.
It was inferior to mass production.

Therefore, the cost of the rotary transformer has been high.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a rotary transformer that has excellent mass productivity and is low in cost.

(Means for Solving the Problems) The present invention provides a rotary transformer in which a conductor is formed into a coil shape on a ferrite core using means such as plating or printing, in which a paste is applied to a predetermined position on one plane of a flat core. By printing shaped ferrite, an annular groove is formed, and a coil is formed in this annular groove.

(Embodiment) FIG. 1 shows a sectional view of an embodiment according to the present invention, and FIG. 2 shows a plan view of an embodiment according to the present invention.

The rotary transformer of this embodiment has an annular portion 102 printed with paste-like ferrite on one surface of a disk-shaped ferrite core 101, and a coil 103 printed with copper between the annular portions 102. A connection electrode 104 printed with copper is formed on the back side of the surface, and the structure is such that this coil 103 and the connection pole xo4 are electrically connected via a through hole 105 formed in the core 101. There is.

FIG. 3 shows a cross-sectional view of a part of the manufacturing process of an embodiment of the present invention. First, as shown in FIG. 3(a), a disk-shaped ferrite core 301 with a through hole 302 is Next, as shown in FIG. 3(b), the core 30
1 page 303.

The coil 304 is formed by printing copper, and the back side 305 is
A connection electrode 306 is formed by printing on the coil 304 and the connection electrode 306 is electrically connected to each other through a through hole 302 . Then, as shown in FIG. 3(C), paste-like ferrite was printed on the surface on which the coil 304 was formed to form an annular portion 307. This coil 304, annular portion 307, etc. were baked at approximately 800°C to 900°C.

Alternatively, the annular portion formed by printing paste-like ferrite may be formed first, and then the coil portion may be formed by printing.

In addition, in the above embodiment, the coil was formed by printing, but
The same applies if the coil and connection electrodes are formed by plating.

In the present invention, the annular groove in which the coil is formed is formed by printing paste-like ferrite, and this makes it extremely easy to set the depth of the annular groove to about 20 to 30 microns. Therefore, it becomes easy to manufacture a rotary transformer using plated coils or printed coils, which facilitates automation and improves mass production.

Therefore, the cost of the rotary transformer can also be reduced.

(Effects of the Invention) The present invention provides that the depth of the annular groove in which the coil is formed is about 20 to
It is extremely easy to obtain a rotary transformer with a diameter of 30 microns, and it facilitates the production of rotary transformers whose coils are formed by plating or printing.It is highly automated and mass-producible, and is a low-cost rotary transformer. It is extremely useful for industry.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention;
Figure 1 is a plan view of an embodiment according to the present invention, Figure 3 is a cross-sectional view of a part of the manufacturing process of the embodiment according to the present invention, and Figure 4 is a cross-sectional view of a conventional example. It is. 101.301...Disc-shaped ferrite core, 102.
307... Annular part printed with paste-like ferrite,
103,304...Coil, 104,306...Connection electrode, 105,302...Through hole. Figure 1 No. 21!1

Claims (1)

[Claims] In a rotary transformer in which a conductor is formed in a coil shape on a ferrite core using means such as plating or printing, an annular groove is formed by printing paste-like ferrite at a predetermined position on one plane of the core, This rotary transformer is characterized by having a coil formed in this annular groove.