JPS6311683Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a rotary transformer, and more particularly to a rotary transformer in which the coil mounting portion is made uneven to improve the magnetic coupling of the rotary transformer.

Traditionally, it has been used in home VCRs, etc., as a rotating transformer that sends and receives signals while rotating relative to the magnetic head that records and reproduces image signals on recording media such as magnetic tape in a non-contact manner. A plane facing type as shown in FIG. 1 is well known.

The plane-facing rotary transformer shown in the figure is made by molding a high magnetic permeability member such as ferrite into a flat cylindrical shape and then sintering it.
An annular groove 3 is provided in the fixed side transformer core 2 and their opposing surfaces, and a flat coil 4 is fixed in this groove 3 with adhesive.
The transformer core 2 and the fixed transformer core 2 are opposed to each other with an extremely small gap therebetween, with the flat coil 4 facing inside.

In such a rotary transformer, the magnetic coupling that ensures stable and reliable electrical signals exchanged between the coils 4 is achieved by the areas S ₁ , S ₂ , _S3 , and in order to respond to the recent miniaturization of electronic devices, it is impossible to reduce the number of turns of the flat coil 4 because it will significantly impair the transmission signal characteristics between the coils 4. Inevitably, the area of the opposing portion S ₁ ,
S ₂ and S ₃ had to be reduced, and the smaller the size, the worse the magnetic coupling.

Furthermore, although it is desirable that the coils 4 be as close as possible, as mentioned above, the workability of installing the coils 4 into the groove 3 and the distance between the transformer cores 1 and 2 through a small gap are important. If the coils 4 were to protrude beyond the respective transformer surfaces, it would be an obstacle during rotation.
It had to be made larger and deeper, which unnecessarily worsened the electrical characteristics.

Furthermore, the disk-shaped coil 4 must be formed using a special winding machine, and in addition, the disk-shaped coil 4 is easily deformed and requires care in handling, and does not remain deformed. If it is fixed in the groove 3, it will not only cause variations in the electrical characteristics of the rotating transformer, but also the work of fixing it in the groove 3 with adhesive will make automatic continuous assembly extremely difficult. Since it is also necessary to check the polarity and number of turns of the coil 4 after installation, it is necessary to maintain the electrical characteristics of this type of rotating transformer in a highly reliable and stable state without sacrificing economic efficiency. There were a wide variety of problems.

This idea was devised in view of the above-mentioned problems, and the purpose is to create an economical rotating transformer that can meet the demands for miniaturization while maintaining good magnetic coupling with a relatively simple configuration. The aim is to provide products with stable quality without sacrificing properties.

Preferred embodiments of this invention will be described below with reference to the accompanying drawings.

Note that the same reference numerals are given to the same or corresponding parts as in the above conventional example.

The rotary transformers shown in the figure have approximately the same shape, made by molding a high magnetic permeability material such as ferrite into a flat cylindrical shape and then sintering it. 2 and a coil 5 formed on opposing surfaces of these transformer cores 1 and 2, and approximately at the center of the rotating and stationary transformer cores 1 and 2 is a shaft hole 6 of a predetermined diameter.
6' is formed, and the transformer cores 1, 2
A drive shaft is inserted into the two transformer cores so that they face each other with an extremely small gap between them, and the upper rotary transformer core 1 is rotated to transmit and receive electrical signals in a non-contact manner.

The rotary transformer shown in the figure has the following features compared to conventional rotary transformers of this type.

That is, on the opposing surface of the upper rotating side transformer core 1, there are a plurality of annular grooves 7 with different diameters.
7' is formed concentrically with the shaft hole 6, and has a cross-sectional shape slightly expanded toward the opposing surface. At positions corresponding to the concave grooves 7, 7', a plurality of convex portions 8, 8' are formed concentrically with the shaft hole 6', have a tapered cross-sectional shape toward the opposing surface, and have their tip portions protruding planarly. It is formed.

In other words, the annular grooves 7, 7' and the protrusion 8,
8' is formed on the rotating side and stationary side transformer cores 1 and 2, respectively, so that the protrusions 8 and 8' can face each other with the protrusions 8 and 8' slightly protruding into the grooves 7 and 7'. 7, 7' and the protrusions 8, 8' may be provided on either side of the transformer core without impairing the effects of the present invention, which will be described later.

Further, the coil 5 is formed in the annular grooves 7, 7' and at the tips of the protrusions 8, 8' by printing and baking a conductive silver paste or the like.

Now, in the configuration as above,
When the rotating transformer core 1 and the stationary transformer core 2 are opposed to each other with an extremely small gap in between, the annular grooves 7 and 7' in which the coils 5 are formed and the convex parts 8 and 8' are at their tips. The parts protrude into the annular grooves 7 and 7', and in addition to the areas S ₁ , S ₂ , and S ₃ of the opposing parts as in the conventional rotary transformer, these inclined surfaces also contribute to magnetic coupling. This will make the bond even stronger.

Further, as described above, the coil 5 is a thick film-like conductive member and is formed by printing, so the film thickness is constant, and unlike a conventional flat plate coil, it is possible to face each other with an extremely small gap. This makes it possible to further improve transmission characteristics.

Therefore, even if the rotating transformer is made quite small, it is possible to do so without sacrificing magnetic coupling or transmission characteristics.

The fact that the coil 5 is formed by baking a conductive member as described above means that the positional relationship between the opposing coils 5 is extremely stable compared to the conventional method of fixing with adhesive. In addition, there is no room for deformation and the handling properties are dramatically improved, and furthermore, there is no need to check the polarity or number of turns of the coil 5.

Furthermore, the forming process of the coil 5 can be carried out by baking the conductive member after printing. For example, it is also possible to provide a baking furnace in a part of the belt conveyor and bake the coil 5 while it is being transported by the conveyor, resulting in automatic continuous assembly. In combination with the above-mentioned effects, it is possible to reduce the production cost while maintaining the quality of the rotary transformer at a high level.

FIG. 3 shows another embodiment of the rotary transformer according to this invention.

The rotary transformer shown in the figure is characterized by the following points, and only the characteristic points will be explained.

That is, in this embodiment, the annular grooves 7, 7' are integrally formed during molding of the rotating transformer core 1 in the first embodiment, whereas the opposing surface of the rotating transformer core 1 is a flat surface. After the coil 5 is formed on the opposing surface, annular projections 9, 9', 9'' are formed with different diameters and are concentric with the shaft hole 6.

That is, an annular groove 7 is formed between the annular protrusions 9 and 9', and an annular groove 7' is formed between the annular protrusions 9' and 9''.

With this configuration, the mold for forming the rotating side transformer core 1 can be a disk-shaped mold with a shaft hole 6 bored in the center, and the number of turns of the coil 5 can be changed or the channel to accommodate it can be changed. This can be applied to changes in the number of molds without changing the molding die, making it possible to further reduce costs. In addition, since the coil 5 is formed into a flat shape, the formation work is extremely easy.
The shape of the coil 5 is formed in an even more stable state.

Incidentally, in the above embodiment, a two-channel rotary transformer has been described, but the implementation of the present invention is not limited to this, and it goes without saying that the number of channels is not limited. Furthermore, although the above-mentioned coil 5 is formed into a thick film by baking, it is also possible to form a thin film by vapor deposition, sputtering, etc. In this case, the coil spacing can be made even closer. .

As described above, the rotary transformer of this invention includes a rotary transformer comprising a rotating side transformer core and a fixed side transformer core and a coil, and has an annular groove formed on the opposing surface of one of the transformer cores, and an annular groove formed in the opposite groove of the other transformer core. Protrusions are provided at corresponding positions, and conductive coils are baked into these grooves and protrusions to transmit and receive electrical signals in a non-contact manner. This makes it possible to achieve magnetic coupling without deteriorating the magnetic coupling, enables mass production by automatic continuous assembly, and makes it possible to provide an economically advantageous rotating transformer with stable quality.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional rotary transformer of this type. FIG. 2 is a sectional view showing an embodiment of the rotary transformer according to this invention. FIG. 3 is a sectional view showing another embodiment of the rotary transformer according to this invention. 1...Rotating side transformer core, 2...Stationing side transformer core, 3...Concave groove, 4...Flat coil, 5
... Coil, 6, 6' ... Shaft hole, 7, 7' ... Annular groove, 8, 8' ... Convex portion, 9, 9', 9'' ... Annular protrusion.

Claims (1)

[Claims for Utility Model Registration] (1) A rotating transformer core having a rotating side and fixed side transformer core made of a high magnetic permeability member such as ferrite formed into a flat cylindrical shape, and a coil for signal transmission on the opposing surface of the transformer core. In the transformer, an annular groove is provided on an opposing surface of one of the transformer cores, and an annular protrusion is formed protrudingly at a position corresponding to the other groove, and the groove and the protrusion are electrically conductive. A rotary transformer characterized in that the coil made of a member is baked and formed, and the transformer core is relatively rotated to transmit and receive electric signals between the coils in a non-contact manner. (2) In the utility model registration claim 1, a plurality of annular protrusions with different diameters are formed on the planar opposing surface of the transformer core, and the recess is formed between the protrusions. A rotating transformer characterized by a groove.