JPH0139641B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary transformer used in VTRs and the like.

Conventionally, it has become common practice to install a shot ring in a rotary transformer in order to improve crosstalk characteristics. This crosstalk characteristic is caused by electrostatic induction or electromagnetic induction, and is related to the phenomenon in which a signal from one channel mixes into another channel.
If this crosstalk characteristic is poor, it will have an adverse effect on the image, and is a very important characteristic of a VTR.

FIG. 1 shows a plan view of a conventional rotary transformer core. Conventionally, the method for installing the above shot ring was to wind a wire and shorten the winding, or to insert a donut-shaped cutout of a copper plate into the shot ring groove 3a. .

However, even with this method, the crosstalk characteristics were not sufficiently improved. In particular, although the crosstalk characteristics between the channels on both sides of the shot ring have been improved, it is completely insufficient to counteract the influence of other channels on the opposing sides.

The present invention has focused on the above points and aims to improve the crosstalk characteristics between opposing surfaces.

In other words, conventionally, since the rotary transformer rotates at high speed, the opposing surfaces were required to be flat with high accuracy. Therefore, the short ring had no effect on the crosstalk characteristics between channels between opposing surfaces. Therefore, the inventor considered making the shot ring protrude from the main plane. In other words, by protruding from the main plane, this shot ring improves the crosstalk characteristics between channels between opposing surfaces. Further, the shot ring protruding from one surface is inserted into the shot ring groove provided on the opposing surface to further enhance the effect.
Of course, at this time, the core on the side into which the shot ring is inserted is not in contact with the shot ring.

A detailed description will be given below based on the drawings. FIG. 2 is a sectional view of a rotary transformer that is still in the process of achieving the present invention. In FIG. 2, windings 21, 22, 2 are provided in each channel groove of the disc-shaped ferrite core.
3 has been applied. Shot ring grooves 24 and 25 are provided between each channel. Shot rings 26 and 27 are joined to the shot ring grooves 24 and 25 so as to protrude from the main plane. A substantially similar ferrite core 28 is provided opposite this ferrite core 20. Of course, the shot ring 26 and the shot ring 29 are not in contact with each other. The same applies to the shot ring 27.

The present invention is a further improvement of the rotary transformer shown in FIG. A sectional view of an embodiment of the rotary transformer according to the present invention is shown in FIG.

In FIG. 3, ferrite cores 30 and 31 each have a winding in a channel groove. In the shot ring grooves, the shot rings 32 and 33 are joined to the shot ring grooves 34 and 35 of the ferrite core 30, but are not joined to and do not contact the shot ring grooves 36 and 37 of the ferrite core 31. This is to prevent mechanical problems such as breakage of the core if the shot rings 36 and 37 connected to the stator core 30 come into contact with the rotor core when the rotor core 31 rotates around the shaft 38. be. It is also possible to join the shot ring to the rotor core 31, but there are problems such as adhesive strength, so it would be better to join it to the stator core 30.

Furthermore, shot rings have conventionally been obtained by punching out a flat copper plate, but the punched copper plate is of little use. However, in the case of the present invention, the shot ring can be made thinner to a certain extent, and it can be used with no waste because it can be cut to an appropriate length than the cylindrical shot ring material shown in FIG.

Further, by further grounding the shot ring installed in this manner, it is possible to improve the crosstalk characteristics.

FIG. 5 shows a graph showing crosstalk characteristics. The core used here is a two-channel rotary transformer core with an outer diameter of 40φ. In Figure 5, graph A is without shot ring, graph B is
Graph C shows the case where a conventional shot ring is used, graph C shows the case where the shot ring of the present invention shown in FIG. 3 is used, and graph D shows the case where the shot ring in graph C is grounded.

As detailed above, if the shot ring according to the present invention is used in a rotary transformer, the crosstalk characteristics will be greatly improved.
It is extremely effective and is very useful for improving the performance of VTRs and the like.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional rotary transformer core, FIG. 2 is a cross-sectional view of a rotary transformer that is in the process of achieving the present invention, FIG. 3 is a cross-sectional view of an embodiment according to the present invention, and FIG. FIG. 5 is a perspective view of the shot ring material according to the present invention, and FIG. 5 is a graph showing crosstalk characteristics. 20, 28, 30, 31... Rotary transformer core, 26, 27, 29, 32, 33... Shot ring, 21, 22, 23... Winding wire.

Claims (1)

[Claims] 1. In a rotary transformer, each of which has a required number of ring-shaped grooves on one main plane, and in which a disc-shaped ferrite core with a coil provided in the ring-shaped groove is arranged with the main planes facing each other, A shot ring is installed between the ring-shaped grooves of the disc-shaped ferrite core, and the shot ring protrudes from the main plane of the ferrite core, and the shot ring is placed in the groove provided on the opposing surface of the other disc-shaped ferrite core. A rotary transformer characterized by being inserted.