JPH0482168B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a rotary transformer used in a video tape recorder, etc., and particularly relates to a rotary transformer in which a coiled conductor is formed into a core by a thin film forming method such as plating, vapor deposition, or sputtering. This relates to a rotary transformer that is directly formed.

(Prior Art) A cross-sectional view of a conventional rotary transformer is shown in FIG. This conventional example is a two-channel rotary transformer, in which two concentric circumferential grooves 302 are formed on one surface of a disk-shaped ferrite core 301, and a coil 303 is attached to the circumferential grooves 302. It is. This coil was usually made by winding a conductive wire in a spiral shape.

However, when using a coil wrapped with this conductor wire, the process of winding the conductor wire in a spiral to form a coil, inserting and gluing the coil into the core takes a lot of man-hours, and we have also proposed a rotary transformer that forms the conductor directly on the core. has been done.

By means of plating, vapor deposition, spatter, etc.
Figure 4 shows a plan view of an example of a rotary transformer in which a coiled conductor is formed directly on the core, Figure 5 shows an enlarged view of the coil section, and Figure 6 shows a sectional view taken along line B-B of Figure 5. . In this example, an annular groove 402 is formed in a disc-shaped ferrite core 401, and a conductor 403 is formed in a coil shape within this annular groove 402, and a lead 404 of this coil is provided in the core 401. It has a structure that is pulled out through a through hole.

Figure 7a shows a schematic diagram of the case where the leads at the beginning and end of the coil are pulled out from separate through holes.
FIG. 7b shows a schematic diagram of the case where the wire is pulled out from two through holes.

In the case of a coil using a conventional wire, the winding start S and winding end F of the coil are set at 1, as shown in Fig. 7b.
It was pulled out through one through hole. For this reason, the magnetic flux 601 due to the lead at the beginning of winding S and the magnetic flux 602 due to the lead at the end of winding F cancel each other because they are in opposite directions, and the magnetic flux at this lead portion did not pose any problem.

(Problem to be Solved by the Invention) However, when a coil is formed using methods such as plating, vapor deposition, and sputtering, it is difficult to pull out the leads at the beginning and end of the coil from the same through hole. As shown in FIG. 7a, the leads at the start of winding S and at the end of winding F were pulled out from separate through holes. In this way, when the leads at the start of winding S and the leads at the end of winding F are pulled out from separate through holes, a magnetic flux 603 due to the lead at the start of winding S and a magnetic flux 604 due to the lead at the end of winding F are generated, and each has an inductance. In the equivalent circuit shown in Fig. 9, the conventional rotary transformer equivalent circuit 9
In 01, the inductance 902 of the lead wire lead-out part was connected in series, increasing the loss and adversely affecting the characteristics of the rotary transformer.

(Means for Solving the Problems) The present invention provides a rotary transformer in which a coil-shaped conductor is directly formed on at least one surface of a ferrite core by means such as plating, vapor deposition, sputtering, etc. A ferrite core is provided with a core through-hole that has a width in the radial direction and extends in the axial direction across the coil in the lead-out portion of the coil, and (1) at least two or more lead-out wire through-holes are provided in the core through-hole. A method for manufacturing a rotary transformer that involves direct injection molding of non-magnetic resin onto a ferrite core.

(2) Hings made of at least two conductive members are arranged in the core through-hole provided in the ferrite core in the direction of the core through-hole, and the conductive member is attached to the ferrite core by direct injection molding of resin. This is a method for manufacturing a fixed rotary transformer.

(Example) A sectional view of an embodiment according to the present invention is shown in FIG. 1, a plan view of an embodiment according to the present invention is shown in FIG. 2a, and an enlarged view of a core through hole provided in a ferrite core. is shown in FIG. 2b, and a cross-sectional view during injection molding is shown in FIG. This example will be explained below.

In the cross-sectional view of FIG. 8 during injection molding, a molding die 804 is provided with a recess into which a ferrite core 801 can be inserted, and the ferrite core 801 is inserted into this recess. Further, the molding die 804 is provided with a recessed portion having a predetermined dimension into which a conductive pin 802 can be inserted and fixed, and the conductive pin is inserted into this recessed portion. In addition, the molding die 806 manufactured by fitting with the molding mold 804 has a concave shape portion for the resin to be manufactured, and a resin pouring hole 80 is formed.
7 is provided. These molding molds 806 and 80
The melted resin 803 is injection molded in a state in which 4 are combined, and after cooling, the molding molds 804 and 806 are divided, and the ferrite core, the resin, and the pin of the conductive member are taken out and manufactured.

Thereafter, a coil is formed by plating, vapor deposition, sputtering, etc. to obtain a desired rotary transformer.

According to the present invention, insulating and non-magnetic resin is injection molded into a single through-hole extending from the winding start to the winding end of the coil, and the ends of the coil are processed. The generation of inductance is eliminated, and deterioration of the characteristics of the rotary transformer can be prevented. Furthermore, since the resin is made by injection molding, a through hole 2 is made as shown in Figure 2b.
It is possible to form a complex shape that cannot be formed by post-press-fitting the resin, in which both end surfaces of the ferrite core 201 and the resin 203 are different from the center, and this is useful for improving the adhesion strength between the ferrite core 201 and the resin 203.

(Effects of the Invention) According to the present invention, it is possible to sufficiently reduce the number of man-hours required to create a rotary transformer by creating a coil by plating, vapor deposition, sputtering, etc., and also to eliminate unnecessary inductance generated in the lead portion. Taking advantage of these advantages, the shape of the resin can be arbitrarily set and the adhesion of the ferrite core can be improved, providing a highly reliable rotary transformer, which is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 a is a plan view of FIG. 1, and FIG.
is an enlarged view of the through hole in FIG. 1, FIG. 3 is a conventional sectional view, and FIG. 4 is a plan view of FIG. 3.
Figure 5 is an enlarged view of the lead part, and Figure 6 is an enlarged view of the lead part.
7 is a schematic diagram of the lead portion of the coil, FIG. 8 is a sectional view of injection molding, and FIG. 9 is an equivalent circuit diagram of the rotary transformer. 101... Ferrite core, 102... Annular groove, 103... Resin, 104... Conductive member, 10
5... Core through hole.

Claims (1)

[Claims] 1. In a rotary transformer in which a coil-shaped conductor is directly formed in a spiral shape on at least one surface of a flight core by means such as plating, vapor deposition, sputtering, etc., the lead of the coil of the ferrite core is A core through hole is formed in the lead-out portion, which crosses the coil, has a width in the radial direction, and extends in the axial direction of the rotary transformer, and a non-magnetic resin member having at least two or more lead-out wire through holes is formed in the core through-hole. A method for manufacturing a rotary transformer, characterized in that a non-magnetic resin is formed on a ferrite core by direct injection molding. 2. In claim 1, at least two core through holes provided in the ferrite core are provided.
A method for manufacturing a rotary transformer, characterized in that pins made of three or more conductive members are arranged in the direction of the core through hole, and the conductive member is fixed to the ferrite core by direct injection molding of a non-magnetic resin.