JPH029106A - Manufacture of rotary transformer - Google Patents

Abstract

PURPOSE:To eliminate unnecessary inductance and prevent characteristic deterioration of a rotary transformer by directly injection-molding non-magnetic resin in a ferrite core so as to have at least two pulling-out wire penetrating holes in a core penetrating hole. CONSTITUTION:A coil-like conductor is directly formed on at least one face of a ferrite core 101 by a means such as plating, deposition and sputtering to become a coil. The coil is crossed in a lead pulling-out part of the coil of the core 101 to have a width radially and a core penetrating hole 105 is formed in an axial direction of a rotary transformer. Non-magnetic resin is directly injection-molded to form in the core 101 so as to from a non-magnetic resin member 103 having at least two pulling-out wire penetrating holes in the penetrating hole 105. Thereby unnecessary inductance produced in a lead part can be eliminated and the characteristic deterioration of the rotary transformer can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotary transformer used in a video tape recorder, etc., and particularly relates to a rotary transformer used for plating and vapor deposition.

The present invention relates to a rotary transformer in which a coiled conductor is directly formed on a core using a thin film forming method such as sputtering.

(Prior Art) A cross-sectional view of a conventional rotary transformer is shown in FIG. 3. This conventional example is a two-channel rotary transformer with one
Two concentric circumferential grooves 302 are formed on one surface of the disc-shaped ferrite core 301, and a coil 303 is mounted in the circumferential grooves 302. This coil was usually made by winding a conductive wire in a spiral shape.

However, when using a coil wrapped with this conductor,
A rotary transformer has also been proposed in which the conductor is formed directly on the core because the process of winding a conductor wire in a spiral to form a coil, inserting and gluing the coil into the core takes a lot of man-hours.

By means of plating, vapor deposition, sputtering, 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, and Figure 5 shows an enlarged view of the coil section.
In this example, an annular groove 402 is formed in a disc-shaped ferrite core 401, and a conductor 403 is inserted into the annular groove 402. It is formed into a coil shape, and this coil glued 404
This is a structure in which the core 401 is drawn out through a through hole provided in the core 401.

Figure 7(a) is a schematic diagram of the case where the leads at the beginning and end of the coil are pulled out from separate through holes.

Figure 7 (b) shows a schematic diagram of the case where it is pulled out from one through hole.
).

In the case of a conventional coil using a wire, the winding start S and winding end F of the coil are drawn out from one through hole, as shown in FIG. 7(b). 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. 7(a). 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 S at the beginning of the first turn and the leads F at the end of the first turn are pulled out from different 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, each having an inductance.In the equivalent circuit shown in FIG. The inductance 902 of the lead-out portion is connected in series, increasing loss and adversely affecting the characteristics of the rotary transformer.

(Means for solving the problems) The present invention is as follows. In 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 radial direction that crosses the coil is attached to a lead extraction portion of the coil of the ferrite core. The ferrite core is provided with a core through hole that has a width of 2 and extends in the axial direction.

1) A method for manufacturing a rotary transformer, in which a non-magnetic resin is directly injection molded onto a ferrite core so that the core through-hole has at least two lead-out wire through-holes.

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

(Example) FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2(a) is a plan view of an embodiment of the present invention.

In addition, an enlarged view of the core penetrating corrosion provided in the ferrite core is shown in FIG. 2(b), 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 80° 4 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. Further, a 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 807 is provided. Molten resin 803 is injection molded with the molding molds 806 and 804 combined, and after cooling, the molding molds 804 and 806 are divided, and the ferrite core, the resin, and the conductive member pin are taken out and manufactured.

After this. A coil is formed by means such as plating, vapor deposition, and sputtering 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, as shown in Figure 2(b),
This makes it possible to form a complex shape that cannot be formed by post-press-fitting the resin, such as where both end surfaces of the through-hole hole 205 are different from the center, and this is useful for improving the adhesion strength between the ferrite core 201 and the resin 2.3. .

(Effect of the invention) According to the present invention. It fully satisfies the reduction in the man-hours required to create a rotary transformer through coil creation using plating, vapor deposition, sputtering, etc., eliminates unnecessary inductance generated in the leads, and takes advantage of the advantages of injection molding to allow the resin to be shaped into any desired shape. This makes it possible to improve the adhesion of the ferrite core, providing a highly reliable rotary transformer, which is extremely useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention. FIG. 2(a) is a plan view of FIG. 1, FIG. 2(b) is an enlarged view of the through hole in FIG. 1, FIG. 3 is a conventional sectional view, and FIG. 3 is a plan view of FIG. 3, FIG. 5 is an enlarged view of the lead portion, FIG. 6 is a sectional view taken along line B-B of FIG. 5, and FIG. 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 a rotary transformer. 101... Ferrite core, 102... Annular groove, 1
03...Resin, 104...Conductive member, 105...
Core through hole. Figure 2 (a) Figure 1 Figure 4 Figure 5 Figure 6 Figure 7 (a) (b)

Claims (2)

[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 ferrite core by means such as plating, vapor deposition, sputtering, etc., the coil is traversed at a lead extraction portion of the coil of the ferrite core, A nonmagnetic resin member is formed in the ferrite core so as to form a core through hole having a width in the radial direction and in the axial direction of the rotary transformer, and to form a nonmagnetic resin member having at least two lead wire through holes in the core through hole. A method for manufacturing a rotary transformer characterized by forming a magnetic resin by direct injection molding. 2. In claim 1, at least two or more pins made of 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 not attached to the ferrite core. A method for manufacturing a rotary transformer, characterized in that it is fixed by direct injection molding of magnetic resin.