JPH0124907Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotary transformer used in VTRs and the like.

Generally, a rotary transformer is a device that transmits signals generated in a rotating body to a fixed part, and conversely supplies signals from a fixed part to a rotating body, and is based on non-contact electromagnetic coupling. In particular, since VTRs use rotating magnetic heads, rotary transformers are widely used to transmit signals between rotating and fixed parts.

An example of a conventional rotary transformer is shown in FIG. Channel grooves 2 and 3 are provided concentrically in the disk-shaped ferrite core 1. FIG. 2 is a cross-sectional view of the core of FIG. 1. Such a rotary transformer has the disadvantage that signals from other channels are mixed in. This drawback is for example
In VTRs, this caused a situation in which the image was adversely affected. This characteristic is called a crosstalk characteristic, and is thought to be caused by the mixing of magnetic flux in each channel. As a countermeasure to this problem, a method of installing shot rings between the channels has been considered. The core 4 in FIG. 3 has channel grooves 5 and 6 and a shot ring groove 7 between the channels. Fourth
The figure is a sectional view of the core 4 of FIG. 3. A short-circuited coil or a doughnut-shaped cutout of a copper plate is inserted into the shot ring groove 7. However, even this method did not completely overcome the above drawbacks.

The present invention aims to eliminate the above-mentioned drawbacks.

That is, in order to block the magnetic path 8 generated between the channels, coils 9 and 10 are provided between the channels to surround the magnetic path 8, and the coils are short-circuited. When magnetic flux passes through section 11 and attempts to mix into other channels, a current is generated in the coils 9 and 10 that generates a magnetic field opposite to the magnetic flux, preventing the magnetic flux from passing through.

This will be explained in detail below with reference to the drawings. FIG. 7 is a plan view of a ferrite core according to an embodiment of the present invention. FIG. 8 is a cross-sectional view of the core of FIG. 7. This core 12 is provided with channel grooves 13 and 14, and between the channel grooves is provided a groove 15 for inserting a short coil according to the present invention, and a groove 16 similar to the groove 15 is provided on the back surface. It is provided. Moreover, the groove 1 for inserting the short coil
5 and 16 are provided with through holes 17. or,
FIG. 9 shows a perspective view of an embodiment of the short coil according to the present invention. This short coil 18 is formed in the short coil insertion grooves 15 and 16. The material of this short coil may be a wire such as a copper wire, a copper plate, etc., or a conductive paste, etc., as long as a one turn short coil is formed. Moreover, this short coil is a coil that surrounds the magnetic path in the core 12 when viewed from the magnetic path direction A between the channels. Therefore, the short coil blocks the magnetic path between the channels.

As detailed above, according to the present invention, it is possible to block the magnetic path generated between the windings, thereby preventing the mixing of signals from other channels, and greatly improving the crosstalk characteristics. It is something that makes you

[Brief explanation of the drawing]

Fig. 1 is a plan view of a conventional core, Fig. 2 is a sectional view of the core of Fig. 1, Fig. 3 is a plan view of a conventional core for attaching a shot ring, and Fig. 4 is a plan view of a conventional core for attaching a shot ring. is a cross-sectional view of the core in FIG.
Figure 6 is a schematic diagram showing the magnetic path of the core,
FIG. 7 is a plan view of the core of the embodiment of the present invention, FIG. 8 is a sectional view of the core of FIG. 7, and FIG.
The figure is a perspective view of an embodiment of the short coil according to the present invention. 12... Core, 15, 16... Groove for inserting the short coil, 17... Through hole, 18... Short coil.

Claims (1)

[Scope of utility model registration request] In a rotary transformer comprising a disc-shaped ferrite core having a plurality of concentric windings with the winding surfaces facing each other, at least one disc-shaped ferrite core has a space between adjacent windings. A circumferential groove is formed, a circumferential groove corresponding to the circumferential groove is also formed on the back side of the surface on which the circumferential groove is formed, and the circumferential groove penetrates through the circumferential groove on the front and back sides. A rotary transformer characterized in that one through hole is formed, and one short coil is arranged in the circumferential groove on the front and back sides and connected through the through hole.