JPH0787154B2 - Rotary transformer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rotary transformer used for signal transmission between relative rotating operations.

(Prior Art) In recent years, video tape recorders that use rotary transformers have made remarkable progress in terms of downsizing, multi-functionalization, high resolution, low price, and the like. Along with this, there has been a demand for a rotary transformer that is smaller, more multi-signal transmission system, higher performance, and lower cost.

A conventional rotary transformer will be described with reference to FIGS. 4 and 5.

FIG. 4 is an enlarged cross-sectional view of a main part of a conventional rotary transformer, showing a case where the signal transmission system has six series.

The rotary transformer is composed of an outer cylindrical core 1 and an inner cylindrical core 2 that relatively rotate about the same rotation center axis. The outer cylindrical core 1 faces the inner peripheral surface, and the inner cylindrical core 2 faces the outer peripheral surface. The outer cylinder coil 3 and the inner cylinder coil 4, which are wound in a cylindrical shape, are housed in the respective six coil grooves 1a and 2a provided in such a manner. Further, the coil grooves 2 are formed on the outer peripheral surface of the inner cylindrical core 2 described above.
The short rings 5 are housed in the ring grooves 2b provided at the middle five positions.

The short ring 5 inserted between each signal transmission system constitutes an independent magnetic circuit for each pair of the outer cylinder coil 3 and the inner cylinder coil 4.

(Problems to be Solved by the Invention) However, in the above configuration, if an attempt is made to increase the number of signal transmission systems with the same size, for example, the characteristics such as the number of coupling systems and inductance will deteriorate, and the same characteristics will be maintained. However, there is a problem that the height of the coil becomes high and the coil becomes large.

The above problem will be described by taking the case where the signal transmission system shown in FIG. 5 has two systems as an example.

FIG. 5A is a sectional view showing the left half of the inner and outer cylindrical cores of a rotary transformer having a signal transmission system of two series. The height h between the inner cylindrical core 2, the coil groove 2a and the ring groove 2b is 2
This is the height required to make the series magnetic circuits independent. now,
If one dimension of the cylindrical core is made into three series, as shown in FIG. 5 (b), since the ring grooves 2b are provided in the middle of the three coil grooves 2a, respectively, the height between the coil grooves 2a and 2b is increased. The height h ₀ naturally becomes smaller than the height h shown in FIG. 5 (a), and therefore the characteristics deteriorate. Further, if the height h is secured in order to maintain the characteristics, the height of the cylindrical cores 1 and 2 becomes high and becomes large in size, as shown in FIG. 5 (c).

According to the present invention, the above-mentioned problems are solved, and within the same dimensions as the conventional one, it is possible to realize a multi-signal transmission system without causing deterioration of characteristics, or to reduce the size and improve the characteristics of the same signal transmission system. The present invention provides a rotary transformer that can realize a low price.

(Means for Solving Problems) In order to solve the above problems, the present invention arranges independent magnetic circuits for every two series or for every two series and one series, and 2 of magnetic circuit composed of series
The facing area of the inner and outer cylindrical cores between the coils of the set is made larger than the facing area of the upper or lower side of the two sets of coils.

(Operation) According to the above configuration, the two series of signal transmission systems constitute one magnetic circuit, and the facing area of the inner and outer cylindrical cores formed in the middle can be made sufficiently large, so that one series of input signals Does not interfere with the other stream. About this, Fig. 2 (a)
And (b).

As shown in FIG. 2 (a), outer and inner cylindrical cores 1 and 2
To the outer cylinder coils 3a and 3b of system 1 and system 2, respectively.
When the cylindrical coils 4a and 4b are mounted and a signal is input to them, an equivalent circuit shown in FIG. 2 (b) occurs. As shown in FIG. 2 (a), the outer cylinder coils 3a and 3b of the system 1 and the system 2 to which the outer and inner cylindrical cores 1 and 2 are mounted, respectively,
Since the facing area of the outer outer-inner cylindrical cores 1 and 2 in the middle of the inner cylindrical coils 4a and 4b is sufficiently larger than the lower facing area of the lower outer-inner cylindrical coils 3b and 4b, it is caused by the input signal of the system 1. Since the magnetic flux passes through the facing area part in the middle,
The interference with the system 2 is suppressed beyond the allowable limit, and the input signal of the system 1 is transmitted as it is as the output signal.

Therefore, in the case of the two-series configuration as shown in FIGS. 3 (a) and (b), the ring groove is omitted, and the interval h between the two upper and lower coil grooves 1a and 2a of the two series facing each other. 'Is significantly larger than the spacing h between the conventional coil groove 2a and ring groove 2b, and is shared by two series,
The rotary transformer characteristics such as the number of coupling systems and inductance can be significantly improved.

Further, if the characteristics are the same as those of the conventional one, as shown in FIG. 3 (c), the interval between the upper and lower coil grooves can be set to h in FIG. 3 (a), and the height of the cylindrical coil can be reduced. can do. Alternatively, the number of sequences in the multi-signal transmission system can be increased at the same height.

(Embodiment) An embodiment of the present invention will be described with reference to FIG. The same components as those in the conventional example are designated by the same reference numerals.

In the figure, the rotary transformer according to the present invention has a short ring 5 at two positions among three groups in which two series are grouped in order to make the six series signal transmission systems independent for every two series.
Is provided. The facing area of the outer inner cylindrical cores 1 and 2 in the middle between the outer inner cylindrical coils 3 and 4 of the two series of each group, system 1 and system 2, system 3 and system 4, system 5 and system 6 shown in the figure Is sufficiently larger than the facing area at the two locations. As a result, the interference between each series falls below the allowable limit, and there is no problem.

In this embodiment, the system 1 and the system 2, the system 3 and the system 4, and the system 5 and the system 6 are paired. However, the system 1, the system 2 and the system 3, the system 4 and the system 5, Various combinations such as the combination of system 6 may be used.

(Effects of the Invention) As described above, according to the present invention, the two series of signal transmission systems are configured by one magnetic circuit, and the facing area between the coils is larger than the facing area on the upper side or the lower side. Since it is configured to be large, the transformer characteristics such as the coupling coefficient and the inductance can be significantly improved if the size is the same as the conventional one. Further, while maintaining the same characteristics as the conventional one, it is possible to downsize and increase the number of signals transmitted.

Further, since the number of independent magnetic circuits is reduced, the number of short rings can be reduced, and productivity can be improved and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a rotary transformer according to the present invention,
2 and 3 are schematic equivalent circuit diagrams of a rotary transformer according to the present invention and schematic cross-sectional views of essential parts for explaining effects and actions, and FIG. 4 is a cross-sectional view of essential parts of a conventional rotary transformer, FIG. 5 is a schematic sectional view of a main part for explaining the problems of the conventional example. 1 ... Outer cylindrical core, 1a, 2a ... Coil groove, 2 ... Inner cylindrical core, 2b ... Ring groove, 3, 3a, 3b ... Outer cylinder coil,
4,4a, 4b …… Inner cylinder coil, 5 …… Short ring.

Claims (1)

[Claims] 1. In a rotary transformer comprising inner and outer cylindrical cores having at least two series of signal transmission systems and rotating with each other, independent magnetic circuits are formed by short rings for every two series or every two series. And the opposing area of the inner and outer cylindrical cores between the two coils of the magnetic circuit configured in two series is set larger than the opposing area of the upper and lower inner and outer cylindrical cores of the two coils. A characteristic rotary transformer.