JPS63246807A - rotating transformer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to crosstalk of a rotating transformer used in a magnetic recording/reproducing device having a rotating magnetic head and transmitting signals between a rotating head section and a fixed section. .

BACKGROUND OF THE INVENTION In recent years, the performance and quality of rotary head type magnetic recording and reproducing devices using rotary transformers have been improved. Therefore, even in a rotary transformer which is one of the components and has a plurality of channels, there is a demand for one with extremely low crosstalk of recording and reproduction signals.

An example of the conventional rotary transformer mentioned above will be described below with reference to the drawings.

FIG. 3 is a sectional view of a main part of a rotary head cylinder in a conventional embodiment, and FIG. 4 is a sectional view of a similar rotary transformer. A rotating side annular magnetic body 3a (hereinafter referred to as R core) attached to a rotating side base material 1a made of a conductive material, and a fixed side annular magnetic body 3b (hereinafter referred to as an R core) attached to a fixed side base material lb also made of a conductive material. The S core (hereinafter referred to as S core) is made by sintering Ni-Zn ferrite or Mn-Zn ferrite with low high frequency loss, and is polished and finished on both sides. R
Winding grooves 7a and 7b are formed in an annular shape on opposing surfaces of each of the core 3a and the S core 3b, and the winding groove 7a on the rotating side
The rotating side coils 5a and 6a are wound around one to several turns.
(hereinafter referred to as R coil) is disposed, and similarly fixed side coils 5b and 6b (hereinafter referred to as S coil) are disposed in fixed side winding groove 7b as well as R coil 5a.

With respect to the number of turns of 6a, the number of turns corresponds to a predetermined y ratio. Further, the R core 3a and the S core 3b face each other with a minute gap of several 10 μm, for example,
When a signal current flows through the coil 5b, a magnetic path C1 as shown by the dotted line
, C2. Then, due to mutual induction, 712i! is applied to the R coil 5a! L is induced and a signal is transmitted. R
The same applies to the case where a signal is transmitted from the coil 5a to the S coil 5b, and the same applies to the transmission from the S coil 6b to the R coil 6a and from the R coil 6a to the S coil 6b. Here, the show 1-ring 8 is formed of an annular short-circuited conductive material, and is short-circuited by utilizing the change in magnetic flux density with respect to time in the magnetic path C2 that occurs when current flows through the S coil 5b, for example. By generating an eddy current in the ring 8, the magnetic flux in the magnetic path C2 is reduced as a result.

By utilizing this phenomenon, it is possible to reduce the current transmitted to the other coil (in the above example, the R coil 6b), thereby improving crosstalk. For example, see Japanese Patent Application Laid-Open No. 60-229201, Saka 1) Minoru, Takayuki Naka, "Rotating Transformer", National Technical Report vol. 18. N14, 1972.
P359-P369).

Problems to be Solved by the Invention However, in the above configuration, for example, S
When a signal current is input to the coil 5b, the current I generated in the R coil 6a is changed to the current 11 generated by the influence of the magnetic field.
When classified into the current I2 generated due to the influence of the electric field,
Due to the eddy current effect of the short ring 8, a current is generated by the magnetic field! 1 can be reduced, but the electric field i!
The current 12 generated by the electric field, which cannot reduce it 12, is: 2=jωε. gsE-3, where ω is the angular frequency of the transmitted signal, C0 is the permittivity of vacuum, εS is the relative permittivity of the material, E is the strength of the electric field, and S is R
This is the surface area of the coil 6a. Here, the dielectric constant εS of the Ni-Zn or Mn-Zn material constituting the ferrite is 10
The frequency of the transmission signal is as high as several 100, and the frequency of the transmission signal is several MHz.
It can be seen that the current I2 has a considerably large value since it is as high as ~ several tens of Mflz. For example, when a current of 15 mA is passed through the S coil 5b at 5 MIIz, the R coil 6
While the current 11 of a is several microamperes, a large current of several tens of microamperes flows in current (2). If the signal frequency is further increased, the current 11 will further decrease due to the eddy current effect of the short ring 8, but the current 2 will conversely increase, so the ratio of the current I2 to the total current 2 will continue to increase. Become.

From these facts, it can be seen that for the purpose of reducing crosstalk, the current I2 flowing due to the influence of the electric field cannot be ignored. In other words, in the above configuration, crosstalk could not be improved because no countermeasures were taken against the current I2 generated by the electric field.

In view of the above problems, the present invention provides a rotary transformer that can improve crosstalk by having a structure that can reduce the current generated by an electric field.

Means for Solving the Problems In order to solve the above problems, the rotating transformer of the present invention has the following features:
It is composed of fixed and rotating magnetic bodies that face each other in the plane or circumferential direction with a certain gap, and two or more pairs of coils that are arranged facing each other on opposing surfaces of the fixed and rotating magnetic bodies, respectively. In the rotating transformer, a short ring short-circuited between at least the coils on the stationary side magnetic body or the rotating side magnetic body is disposed, and the short ring is electrically grounded.

Effect of the Invention With the above-described configuration, the present invention makes it possible to reduce the value of the current generated due to the influence of the electric field among the current generated in the coil that is not related to the original signal transmission, and it is possible to improve crosstalk.

EXAMPLE Hereinafter, a rotary transformer according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of a main part of a rotating head cylinder according to an embodiment of the present invention, and FIG. 2 shows a sectional view 1 of a similar rotating transformer and a stationary side base material. In FIGS. 1 and 2, R? placed on the S core 3b? The short-circuited short ring 8 made of an ilt material and the fixed side base member 1b, which is also made of a conductive material and is in an electrically grounded state, are electrically connected by one or more connecting pins IO made of a conductive material. It is connected. Further, connection holes 11 for passing the connection pins 10 are provided in the S core 3b in accordance with the number of connection pins 10.

Now, in this embodiment, consider, for example, the current generated in the R coil 6a when a signal current is passed through the S coil 5b. Here, the current ■3 generated in the R coil 6a
Assuming that the current 4 generated due to the influence of the magnetic field and the current 15 generated due to the influence of the electric field are, the magnetic flux passing through the magnetic path C4 is reduced by the eddy current effect of the short ring 8, so the current generated due to the influence of the magnetic field is (2) 4 can be made smaller than when the short ring 8 is not present. For this purpose, attention is paid to the current I5 generated due to the influence of the zero-order electric field, which was also explained in the conventional example. The potential will be distributed in the surrounding field due to the surface potential of the S coil 5b, which is the input source, but since the short ring 8 is grounded by the connection pin 10, the potential near the R coil 6a will be small. . The strength of the electric field is the gradient of potential E=gr
Since adφ is generated, the strength of the electric field is also smaller than when the short ring is not grounded. As mentioned above, the current I5 generated due to the influence of the electric field is 1
5=jωε. Since the short ring is flooded with ε5E-3, the electric field strength E becomes smaller, so the current I5 generated due to the influence of the electric field can be made smaller than when the short ring is not grounded.

As described above, according to this embodiment, by grounding the short ring 8 disposed on the S core 3b, the strength of the electric field near the coil, which is not related to the original signal transmission, can be reduced. Therefore, the current generated due to the influence of the electric field can be made smaller than when the short ring 8 is not grounded. Therefore, crosstalk can be improved.

In the embodiments described above, the short ring disposed on the fixed-side annular magnetic body was grounded to the fixed-side base material in the grounded state, but conversely, the short ring disposed on the rotating side annular magnetic body It goes without saying that the ring may be grounded to the rotating side base material that is in the grounded state.Furthermore, in the embodiments described above, a surface facing type rotary transformer has been explained, but a circumferentially facing type rotary transformer has been described. A similar configuration can be applied to a rotary transformer.

Effects of the Invention As described above, the present invention reduces the strength of the electric field near the coil, which is not related to the original signal transmission, by grounding the short ring 8 disposed on the S core 3b. Therefore, the current generated due to the influence of the electric field can be made smaller than that in the case where the short ring is not grounded, so that crosstalk can be improved.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a main part of a rotary head cylinder according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a similar rotary transformer and fixed side base material, and FIG. 3 is a rotary head cylinder according to a conventional embodiment. FIG. 4 is a sectional view of a similar rotary transformer. 1...Base material, 3...Magnetic material, 5...
... Coil, 6... Coil, 7...
Winding groove, 10... Connection pin, 11...
Connection hole, CI, C2, C3, C4...magnetic path.

Claims (1)

[Claims] It is composed of fixed and rotating magnetic bodies that face each other in the plane or circumferential direction with a certain gap, and two or more pairs of coils that are arranged facing each other on opposing surfaces of the fixed and rotating magnetic bodies, respectively. The rotating transformer is characterized in that a short ring is disposed between at least the coils of the stationary side magnetic body or the rotating side magnetic body, and the short ring is electrically grounded. Rotating transformer.