JPH01158708A - Rotary transformer - Google Patents

Abstract

PURPOSE:To simultaneously reduce the crosstalk of adjacent channels from low to high frequencies by forming an annular thin superconductor film surrounding a coil at a position isolated from the coil. CONSTITUTION:A magnetic flux generated by currents flowing to rotary side coils 1a, 1b forms a magnetic path with stationary side coils 2a, 2b thereby to induce voltages at the coils 2a, 2b, thereby transmitting a signal. Here, since a superconductor exhibits a completely diamagnetic property, the magnetic flux generated by the currents flowing to the coils 1a, 1b does not cross annular thin conductor films 3a, 4a and 3b, 4b surrounding them. Accordingly, the magnetic flux generated from the coil 1a does not link with coils 1b, 1b of the adjacent channels, and the magnetic flux generated from the coil 1b does not link with the coils 1a, 1a of adjacent channels. Thus, the crosstalk between a first channel and a second channel becomes small.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to, for example, a video tape recorder, etc.
This invention relates to a rotary transformer that transmits signals between a rotating magnetic head and a signal circuit system.

[Conventional technology]

Figure 5 shows, for example, the document "National Technical Report J
(Vol. 8. No. 4. ALIG, 1972.1)
, 36B, is a sectional view showing a conventional general two-channel coaxial rotary transformer shown in "R Rotating Transformer" by Minoru Sakata and Takashi Tanaka. In the figure, la and lb are respectively provided in the rotating core 5. The first channel is a rotating side coil, and the second channel is a rotating side coil. 2a,
Reference numerals 2b denote a first channel fixed coil and a second channel fixed coil provided in the fixed core 6, respectively. 7 is a rotating side short ring provided on the rotating core 5, and 8 is a stationary side short ring provided on the fixed core 6.

Next, the operation will be explained.

The magnetic flux generated by the current flowing through the rotating coils la and lb is the fixed coil 2a, respectively.

2b to form a magnetic path, voltage is induced in the fixed side coils 2a and 2b, and signals are transmitted. However, the magnetic flux generated by the current flowing through the rotating coil 1a also forms a magnetic path surrounding the rotating coils la, lb and the stationary coils 2a, 2b, and a voltage is also induced in the stationary coil 2b, causing the first
Crosstalk between the channel and the second channel occurs. Therefore, by providing short rings 7.8 between the rotating side coils and between the stationary side coils, a back electromotive force is generated in the short rings, generating magnetic flux in the direction of canceling the leakage magnetic flux, and thereby generating the first channel and the fixed side coils. Crosstalk between two channels can be reduced.

[Problem that the invention seeks to solve]

Conventional rotary transformers are configured as described above, and when magnetic flux interlinks with the short ring, it generates a back electromotive force that cancels out the leakage magnetic flux and reduces crosstalk, but the short ring has electrical resistance. Therefore, there is a limit to the low frequency range of this crosstalk, and there is a problem in that the effect of reducing crosstalk is particularly small at low frequencies.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a low retransformer that can simultaneously reduce crosstalk between adjacent channels from low frequencies to high frequencies.

[Means for solving problems]

The rotary transformer according to the present invention has an annular superconducting thin film surrounding the coil formed at a position spaced apart from the coil.

[Effect]

In this invention, the completely diamagnetic nature of the superconductor thin film prevents magnetic flux from passing through, reducing crosstalk between coils in adjacent channels.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a rotary transformer according to an embodiment of the present invention. In the figure, 1a and 1b are the rotating coils of the first channel provided in the rotating cores 5a and 5b, and the rotating side coils of the second channel. It is a side coil. 2a,
Reference numerals 2b denote a first channel fixed coil and a second channel fixed coil provided in the fixed cores 6a and 6b, respectively. 3a and 3b are superconducting thin films of, for example, lanthanum, barium, and copper oxide provided on the rotating cores 5a and 5b, respectively, and 4a and 4b are superconducting thin films provided on the fixed cores 6a and 6b, respectively. 9 is a rotating core support stand;
10 is a fixed core support stand.

Next, the operation will be explained.

The magnetic flux generated by the current flowing through the rotating coils la and lb forms magnetic paths with the fixed coils 2a and 2b, respectively, and the fixed coils 2a and 2b, respectively.

A voltage is induced in 2b, and a signal is transmitted.

Here, since the superconductor exhibits a completely diamagnetic property, the magnetic flux generated by the current flowing through the rotating coils la, lb does not interlink with the superconductor thin films 3a, 4a and 3b, 4b, respectively. Therefore, the magnetic flux generated from the rotating coil 1a is transmitted to the adjacent channel coils lb, 2b and the rotating coil 1.
The magnetic flux generated from b flows through the coils la and 2 of the adjacent channel.
Not interlinked with a. This reduces crosstalk between the first channel and the second channel.

Although the above operation is performed by cooling the superconductor thin film to a temperature below the critical temperature, the rotary transformer according to the present invention can effectively operate even at room temperature if a superconductor whose critical temperature is above room temperature is used.

In the above embodiment, the present invention was applied to a two-channel flat rotary transformer, but the present invention may also be applied to a two-channel coaxial rotary transformer, as shown in FIG. The same effects as in the above embodiment are achieved.

Furthermore, in the above embodiments, the superconductor thin film has a planar cross section, but as shown in FIG.
Curved superconductor thin films 3c, 3d, 4c, and 4d may also be used.

Further, in the above embodiment, the rotating cores 5a, 5b, the fixed core 5
a and 5b are rotating core support stands 9, except for the core-opposing surface.
and fixed core support 10, but as shown in FIG. 4, it may be arranged so as to be exposed from the rotating core support and fixed core support. The same effects as in the embodiment are achieved.

〔Effect of the invention〕

As described above, in a rotary transformer according to the present invention, since the coil is surrounded by a superconducting thin film, crosstalk between adjacent channels can be reduced, and the distance between the coils between adjacent channels can be reduced. However, since the crosstalk is small, it is possible to obtain a small rotary transformer.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a two-channel flat rotary transformer according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a two-channel coaxial rotary transformer according to another embodiment of the present invention, and FIG. 4 is a cross-sectional view showing a two-channel flat rotary transformer according to another embodiment of the present invention, and FIG. 5 is a cross-sectional view showing a conventional two-channel coaxial rotary transformer. 1a is the rotating side coil of the first channel, 1b is the rotating side coil of the second channel, 2a is the fixed side coil of the first channel, 2b is the fixed side coil of the second channel, 3a,
3b, 4a, 4b are superconducting thin films; 5a, 5b are rotating cores; 6a, 6b are fixed cores; 9 is a rotating core support; 10
is a fixed core support base. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) A rotating core and a fixed core are formed in a pair and face each other through a gap, and the rotating core is provided with a rotating coil, and the fixed core is magnetically connected to each of the rotating coils. In a rotary transformer provided with a plurality of fixed side coils that are combined to form a plurality of magnetic paths, a rotary transformer is provided in which a plurality of coils on the rotating side and the fixed side are arranged apart from each other, except for the facing surfaces of the rotating core and the fixed core. A rotary transformer characterized by forming an annular superconducting thin film surrounding a coil.