JPH02214109A - Rotary transformer - Google Patents

Abstract

PURPOSE:To reduce a distributed capacity of individual coils of a rotary transformer and to improve a high-frequency characteristic by a method wherein adjacent conducting wires are wound at interval nearly equal to a diameter of a conductor and both ends of the coils are pierced through small holes made in grooves of a magnetic substance core which houses the coils and are extracted from faces opposite to faces where the grooves have been formed. CONSTITUTION:Conducting wires forming individual coils 3p to 3s are wound at intervals nearly equal to a diameter of a core wire. As a result, a distributed capacity of the individual coils 3p to 3s is reduced, and a high-frequency loss at the individual coils 3p to 3s is reduced. The conducting wires at winding start parts and at winding end parts of the individual coils 3p to 3s are extracted immediately from the winding start parts and the winding end parts to faces opposite to faces where grooves 6a to 6d have been termed. Accordingly, the extracted conducting wires do not cross any coils; even when a plurality of coils simultaneously run on a tape, it is possible to suppress an unnecessary crosstalk. Thereby a high-frequency characteristic can be enhanced.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a rotary transformer for transmitting recording and reproduction signals between a rotary head and a fixed circuit part in a VTR (video tape recorder) or the like. It is something.

[Conventional technology]

To explain a general two-Hellard type helical scan VTR, for example, as shown in FIG. - 42b is provided, and the opposing grooves 4.1a and 42a, 41b and the four yoke are formed in exact symmetrical positions.

A coil 41 is provided in each groove of the magnetic cores 41 and 42.
The coil 41p stored in the groove 41a transmits signals to and from the coil 42p stored in the groove 42a, and the coil 41p stored in the groove 42a transmits signals to and from the coil 42p stored in the groove 41b. The coil 41q located in the groove 42b can mutually transmit signals with the coil 42q housed in the groove 42b. Then, the magnetic cores 41 and 42 and the coils 41p, 42p and 4
1q and 42q form a rotary transformer 40. Further, a magnetic core 41 is fixed to a fixed drum (not shown) in the head drum of the VTR. A magnetic core 42 is fixed to a rotating drum (not shown) of the head drum to which the magnetic head is attached, and the magnetic core 42 on the rotating drum side rotates in close proximity to the magnetic core 41 on the fixed drum side. It looks like this. Magnetic core 41
The through holes 41c and 42c formed at the center of the holes 41 and 42 are for passing the rotating shaft of the rotating drum of the head drum.

In the rotary transformer 40, each coil 41p, 41
q, 42p and 42q, as shown in FIG. 5, are formed by closely winding insulated conductive wires 40x... coated with extremely thin resin. Moreover, the winding start and winding of each of the above-mentioned coils 41p etc. are as shown in FIG. 6(a).
For example, in the coil 41q, the groove 4 in the magnetic core 41
A leader line groove 4 provided perpendicular to 1a and 41b
1d.

As shown in FIG. 6(b), this lead wire groove 41d is similar to the grooves 41a and 41 in which the coils 41p and 41q are accommodated.
The wire of the coil 41q is formed to be deeper than the coil 41q, and the lead wire of the coil 41q closely crosses under the coil 41p to prevent the drawn cotton from floating up and coming into contact with the opposing magnetic core 42. It has become.

[Problem to be solved by the invention]

By the way, in VTRs in the early stages of development, the maximum frequency transmitted by the rotating transformer was relatively low, but high resolution,
Many developments have been made one after another in response to demands for high-quality image recording and playback, as well as more stable still image and slow-motion playback. As a result, the high frequency limit that the rotary transformer should transmit is gradually increased, the high frequency loss due to the distributed capacitance of the rotary transformer coil becomes large, and the high frequency characteristics of the rotary transformer deteriorate, resulting in the failure of the expected high-quality images. This may impede recording/playback, or increase the number of magnetic heads or increase the angle at which the tape is wrapped around the head drum, causing multiple heads to run over the tape at the same time. There has been a problem in that the lead wires at the beginning of winding and at the end of winding closely cross other coils, causing harmful loss talk and impairing image quality.

[Means to solve the problem]

In order to solve the above-mentioned problems, the rotary transformer of the present invention has two magnetic cores wound in a concentric groove symmetrically provided on the opposing surfaces of two closely coaxially opposing magnetic cores. In a rotating transformer that houses a coil and transmits an alternating current signal between opposing coils while one magnetic core rotates, the coil has adjacent conducting wires spaced apart from each other with an interval approximately equal to the diameter of this conducting wire. While being wound, both ends of the coil pass through small holes provided in the groove of the magnetic core in which the coil is housed, and are drawn out to the surface opposite to the surface provided with the groove. It is characterized by

[For production]

With the above configuration, the distributed capacitance between the conductive wires forming the coil of the rotary transformer is significantly reduced, so that high frequency components are less likely to be lost in the rotary transformer. That is,
The high frequency characteristics of the rotating transformer are improved, and it is possible to prevent a decrease in the resolution of recorded and reproduced images.

In addition, by pulling out the lead wires at the beginning and end of winding of the coil of the rotary transformer from the small hole provided in the magnetic core to the surface opposite to the surface provided with the groove that accommodates the coil, these wires can be drawn out. The lead wires do not cross other coils closely, which improves high frequency characteristics and suppresses the occurrence of crosstalk.

(Example) An example of the present invention will be described below based on FIGS. 1 to 3.

The rotary transformer 1 of the four-head helical scan type VTR shown in FIG. It consists of a rotation side unit 5 connected to 4...

Taking the fixed side unit 3 as an example, the circular flat magnetic core (hereinafter referred to as the core) 6 has the following components, as shown in FIG.
Four concentric grooves 6a to 6d are provided, and each of the grooves is provided with oblong small holes 6e to 6h as holes for starting winding of the coil and for drawing out conductor wires during winding. Further, a stepped portion 61 is provided on the surface of the core 6 opposite to the surface on which the grooves 6a to 6d are provided, and a portion of the stepped portion 61 is provided with a connecting portion made of an insulating material. The board 7 is
It is fixed by adhesive etc. Note that the through hole 6j formed at the center of the core 6 is for penetrating the head drum rotating shaft.

In the grooves 6a to 6d of the core 6, the coils 3p to 3S of the fixed side unit 3 of the rotary transformer l shown in FIG.
It has been rolled up about 8 times and stored. In this case, the same conducting wire is generally used for the coils 32 to 3S. When using a general insulated copper wire with an extremely thin resin coating on the conductor core wire, as shown in Figure 3(a),
These conductive wires 6X... are wound around each other at intervals approximately equal to the diameter of the conductive wires. Alternatively, as shown in FIG. 3(b), an insulator 8 with low high frequency loss can be used between the conductors 6x...
The conductive wires 6X are wound so as to maintain an interval approximately equal to the diameter of the conductor wires 6X. Also, as another method,
As shown in Figure 3 (C), conductor core wire 6X'' is coated with a sufficiently thick resin coating 6X''', and its outer diameter is approximately twice the diameter of the conductor core wire. 6x・
... may be rolled up closely. In this case as well, it is necessary to select a material that covers the conductor core wire with low high frequency loss.

As described above, by winding the conductive wires forming each coil 32 to 3S at intervals approximately equal to the diameter of the core wire, ~3n is reduced to the distributed capacitance 3 of each coil 3p to 3S,
High frequency loss in each coil 3p to 3s can be reduced.

When each of the coils 32 to 3s is wound as described above, the winding start and winding end portions of the coils 3p to 3S are
As shown in FIGS. (a) and (c), the grooves 6a to 6a of the core 6
The above groove 6 is inserted through the small holes 6e to 6h provided in 6d.
A conductor (not shown) is drawn out to the surface opposite to the surface on which terminals a to 6d are provided, is fixed to the terminals 7a, 7a to 7d, and 7d of the connection board 7 by soldering, and is further provided on the connection board 7. is wired to the amplifier. in this way,
The conductors at the winding start and the winding portion of each coil 32 to 3S are immediately pulled out from the winding start and the winding point to the surface opposite to the surface on which the grooves 6a to 6d are provided. The conductor no longer crosses any coil, even if multiple coils run on the tape at the same time.
Unnecessary losstalk is suppressed from occurring.

The rotating unit 5 fixed to the rotating drum side of the rotating transformer 1 is also formed with the same structure as the stationary unit 3 described above. In this case, the coils 52 to 5S facing the coils 3p to 3S of the fixed unit 3 are connected to the magnetic head 4.
...but since the entire unit rotates,
A connection board having a shape different from that of the connection board 7 for the fixed unit 3 is used. Also in the rotation side unit 5, the distributed capacity 5 of each coil 52 to 5s
~5n decreases, and high frequency loss in the coils 5p to 5S decreases, and unnecessary loss talk is also suppressed.

In addition, in the above embodiment, the grooves 6a to 6 provided in the core 6
Although the small holes 6e to 6h of d are formed in an oval shape, they can be formed in any shape such as a circle or a rectangle. Further, the number of small holes 6e to 6h formed is not limited.

Further, in the above embodiment, a rotary transformer formed by two circular flat cores was described, but a cylindrical transformer that is fitted and fixed to the head drum rotation shaft and rotates integrally with the head drum rotation shaft. A rotating side core and a cylindrical fixed side core are arranged close to each other coaxially with the rotating side core,
The present invention can be similarly applied to a cylindrical rotary transformer in which coil housing grooves are provided concentrically on opposing surfaces of the rotating and stationary cores.

〔Effect of the invention〕

As described above, in the rotating transformer of the present invention, in order to reduce high frequency loss and crosstort in the coil of the rotating transformer, two magnetic cores are arranged symmetrically on the opposing surfaces of two closely coaxially opposing magnetic cores. The wound coil is stored inside the provided concentric groove, and while one magnetic core rotates,
In a rotary transformer that transmits an alternating current signal between opposing coils, the coils have adjacent conducting wires wound at intervals approximately equal to the conductor diameter of the coils, and both ends of the coil are The magnetic core is constructed so that it passes through a small hole provided in a groove of the magnetic core housed therein and is drawn out to the surface opposite to the surface where the groove is provided.

As a result, the distributed capacitance of each coil of the rotary transformer is significantly reduced, and high frequency loss is reduced, thereby improving the high frequency characteristics of the rotary transformer.

In addition, the lead wires of each coil (at the beginning and winding) are
Since it no longer crosses other coils in close proximity, it is possible to reduce harmful losstalk that impairs image quality, making it possible to record and play back up to high frequencies, and to obtain high-quality images with less noise. play.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, in which FIG. 1(a) is a plan view of the surface of the stationary unit of the rotary transformer on which the coil groove is not provided; (
b) is a longitudinal cross-sectional side view of the stationary unit, Fig. 1 (C) is an enlarged partial plan view showing the beginning of winding of the coil and the drawn state of Ichihiragi, and Fig. 2 is a schematic circuit of the rotary transformer and its surroundings. It is a diagram. Figure 3 shows the arrangement of the conductors in the grooves of each coil, and Figure 3 (a) is a longitudinal cross-sectional view of a general covered conductor wire rolled up at intervals, and Figure 3 (b) ) is a vertical cross-sectional view of a general covered conductor wire rolled up with an insulator interposed between them, and FIG. 3(c) is a vertical cross-sectional view of a conductor wire with a thick coating and tightly wound. 4 to 6 show a conventional example, in which FIG. 4 is a vertical cross-sectional view showing a schematic structure of a rotary transformer, and FIG. 5 is a main part showing an arrangement of coil conductors housed in a groove. longitudinal section,
Fig. 6 shows a method for starting winding of a coil and drawing out the winding. Fig. 6 (a) is an enlarged partial plan view showing the state of starting winding and drawing out the winding, and Fig. 6 (b) shows a method of drawing out the winding. FIG. 3 is an enlarged partial side view showing a main part of a core pull-out groove. 1 is a rotating transformer, 3 is a fixed side unit, 3p to 3s are coils of the fixed side unit, 5 is a rotating side unit, 6 is a magnetic core of the fixed side unit, 6a to 6d are grooves for storing the coils, 6e to 6h are small holes for pulling out at both ends of the coil, 6x
8 is a covered conductor, and 8 is an insulator. Figure 1 (a) Figure 1 (b) Patent applicant Sharp Co., Ltd. Figure 1 (a)

Claims (1)

[Claims] 1. The wound coil is housed inside a concentric groove symmetrically provided on the opposing surfaces of two closely coaxially opposing magnetic cores, and while one magnetic core rotates, In a rotating transformer that transmits an alternating current signal between coils, the above-mentioned coil has adjacent conducting wires wound at intervals approximately equal to the diameter of the conducting wire, and both ends of the coil are A rotary transformer, characterized in that the magnetic core extends through a small hole provided in a groove of the magnetic core and is drawn out to a surface opposite to the surface in which the groove is provided.