JPH03227003A - Manufacture of rotary transformer - Google Patents

Abstract

PURPOSE:To accomplish both cost reduction and production yield improvement through automation by a method wherein the desired conductive coil pattern and short-ring pattern are transferred to the surface of a rotary transformer core from a film. CONSTITUTION:A film 2 is brought into contact with the surface of a rotary transformer core 1 consisting of disc-shaped ferrite. Desired conductive coil patterns 3 and 4 and a short-ring pattern 5 are provided on the film 2, the film 2 is pressure-bonded to the rotary transformer core 1, and the helical coil patterns 3 and 4, which are provided on the film 2, and a circular short-ring pattern 5 are transferred to the surface of the rotary transformer core 1. Besides, the helical coil patterns 3 and 4, which are provided on the film 2, and the circular short-ring pattern 5 are coated with a bonding agent in advance, and these patterns can be transferred by pressure-bonding. As a result, the above-mentioned operations can be automated substantially, and the cost of the title transformer can also be cut down.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a rotary transformer used for transmitting and receiving signals to and from a rotating magnetic head of a video tape recorder, digital audio tape recorder, or the like.

Conventional rotary transformers include a disk type in which a groove is provided in a disk-shaped ferrite core and a coil made of coated copper wire is inserted into the groove, and a disk type in which a groove is similarly provided in a cylindrical ferrite core and a coil made of coated copper wire is inserted into the groove. There are two types: a cylindrical type (generally called a coaxial type) in which a coil made of copper wire is inserted.

FIG. 3 is a top view of a disc-type rotary transformer, and FIG. 4 is a sectional view taken along line AA' in FIG.

In both figures, 11 is a rotary transformer core made of ferrite, into which coils 12 and 14 made of coated copper wire are inserted into grooves provided on its surface. Reference numeral 13 denotes a ring for preventing coupling between the coils. A ring-shaped conductor is inserted into a groove provided in a rotary transformer core 11.

Video CHI recorder A digital audio CH recorder uses a rotary transformer having this configuration as a two-side assembly, with the sides on which the coils 12, 14 and the short ring 13 are provided facing each other.

FIG. 5 is a sectional view showing the configuration of a coaxial type rotary transformer.

Reference numeral 15 denotes a rotary transformer core made of ferrite called an outer core, which is attached to the rotor portion of the rotating head, and coils 16 and 17 formed of coated copper wire are inserted into grooves provided on the inner peripheral surface of the core. Reference numeral 18 denotes a rotary transformer core made of ferrite called an inner core that is attached to the stator part of the rotating head, and a coil 1 formed of coated copper wire in a groove provided on the outer peripheral surface of the rotary transformer core.
921 and the short ring 20 are inserted.

Note that most common disk type rotary transformers have a 5-channel configuration with individual coils, and coaxial type rotary transformers often have a 5-9 channel configuration, but here, for ease of explanation, we will use 2 channels. It is shown in the channel configuration.

The conventional method for manufacturing a disc-type rotary transformer having the above configuration involves inserting into a groove provided in the rotary transformer core 1 an air-core coil with coated copper wire wound a required number of times in advance and a ring made of a conductor. A coil 12, 14 and a short ring 13 are formed by fixing with adhesive.

In addition, in the conventional manufacturing method of a coaxial type rotary transformer, a part of the inner coil 19 is wound by directly winding a coated copper wire and a conductor a necessary number of times in a groove provided on the outer periphery of the inner core 18.
．． 21 and short ring 20 are formed.

For the outer part, similar to a disc-type rotary transformer, an air-core coil with a pre-coated copper wire wound the required number of times is inserted into a groove provided on the inner periphery of the outer core 15, and fixed with adhesive to form the coil 16. form 17.

Problems to be Solved by the Invention In such a conventional rotary transformer manufacturing method, apart from a part of the coaxial type inner, an air core coil and a short ring are made in advance and fixed with adhesive. Rotary transformers become expensive as they cannot be automated. In addition, when inserting an air-core coil into the outer core of a coaxial type, first deform the circular air-core coil into a heart shape, fit the deformed air-core coil into the groove provided on the inner periphery of the outer core, and then Since the process involves using a tool to return the product to its original circular shape, there is a problem in that errors occur frequently during the deformation into the heart shape and during the process of returning the product to the circular shape, resulting in poor yield.

SUMMARY OF THE INVENTION In view of the problems of the conventional manufacturing method described above, an object of the present invention is to provide a method for manufacturing a rotary transformer that can be automated and has a high yield.

Means for Solving the Problem In order to solve this problem, the present invention brings into contact a conductive film having a desired coil pattern and a short ring pattern on the surface of a core for a rotary transformer, and the coil pattern and the short ring pattern on the film are brought into contact with the surface of a core for a rotary transformer. The present invention is a method of transferring a ring pattern onto the surface of the rotary transformer core.

Effects By having the above structure, the present invention can form coils and short rings directly on the disc-shaped and cylindrical cores for rotary transformers, thereby reducing costs through automation and improving yield.

Example Hereinafter, the present invention will be explained in detail based on examples.

FIG. 1 is a perspective view showing an embodiment of the present invention. In the figure, reference numeral 1 denotes a rotary transformer core made of disk-shaped ferrite, and a film 2 is brought into contact with the surface of the rotary transformer core 1. The film 2 is provided with a desired conductive coil pattern 3.4 and a short ring pattern 5, and the film 2 is crimped onto the core 1 for a rotary transformer, and the spiral coil patterns 3, 4 and A circular short ring pattern 5 is transferred onto the surface of the rotary transformer core 1.

Both ends of each transferred coil are led out to the opposite surface of the rotary transformer core 1 through through holes (not shown) provided in the rotary transformer core 1 in advance and connected to external terminals (not shown).

The spiral coil pattern 3.4 and the circular short ring pattern 5 provided on the film 2 are coated with an adhesive in advance, and can be transferred by pressing the adhesive.

Furthermore, by making the adhesive thermosetting and heating it at the same time as the pressure bonding, the adhesive strength of each transferred pattern can be increased.

FIG. 2 is a sectional view showing another embodiment of the present invention.

In the figure, reference numeral 6 denotes a rotary transformer core made of cylindrical ferrite, and a cylindrical film 7 is brought into contact with the inner peripheral surface of the core. A desired conductive coil pattern (not shown) and a short ring pattern (not shown) are provided on the outer circumferential surface of the film 7, and the film 7 is crimped onto the rotary transformer core 6. A spiral coil pattern (not shown) and a circular short ring pattern (not shown) provided on the rotary transformer core 6 are transferred to the inner circumferential surface of the rotary transformer core 6.

An adhesive is applied in advance to the spiral coil pattern and the circular short ring pattern provided on the outer peripheral surface of the film 7, and transfer is possible by pressing the adhesive.

Furthermore, by making the adhesive thermosetting and heating it at the same time as the pressure bonding, the adhesive strength of each transferred pattern can be increased.

Both ends of each coil are led out to the outer peripheral surface of the rotary transformer core 6 through through holes (not shown) provided in the rotary transformer core 6 and connected to external terminals (not shown) as in the previous embodiment. .

According to this embodiment, it is possible to form a ring even in a part of the outer layer, which has been extremely difficult in the past, and crosstalk between channels can be significantly improved.

Note that the formation of the coil and short ring on a part of the inner is omitted because the only difference is that the surfaces on which these are formed are the inner and outer surfaces of the cylindrical core.

In addition, a recess is provided in advance in the part where the coil will be formed,
If a coil is formed in the recess and a short ring is formed on a normal surface, the efficiency of blocking the magnetic flux of the short ring can be improved and crosstalk between channels can be significantly improved.

This effect is the same for both the disk shape and the cylindrical image shape.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, a desired conductive coil pattern and a short ring pattern are transferred from a film onto the surface of a core for a rotary transformer to create, insert, and bond an air-core coil. This eliminates the need for rotary transformers, achieves significant automation, and provides an inexpensive rotary transformer.

In addition, a short ring can be formed even in a part of the outer layer, which has been extremely difficult in the past, and crosstalk between channels can be significantly improved.

Further, by forming the coil in a recess provided in the rotary transformer core, crosstalk between channels can be further improved.

[Brief explanation of drawings]

1 and 2 are a perspective view and a sectional view showing an embodiment of the present invention, FIGS. 3 and 4 are a top view and a sectional view showing a conventional example, and FIG. 5 is a top view and a sectional view showing a conventional example. FIG. 1.6...Core for rotary transformer, 2,7
...Film, 3.4...Coil pattern, 5...Short ring pattern.

Claims (4)

[Claims] (1) A rotary transformer in which a conductive film having a desired coil pattern and a short ring pattern is brought into contact with the surface of a core for a rotary transformer, and the coil pattern and short ring pattern on the film are transferred to the surface of the core for a rotary transformer. Transformer manufacturing method. (2) The method for manufacturing a rotary transformer according to claim 1, wherein the core for the rotary transformer has a disk shape. (3) The method for manufacturing a rotary transformer according to claim 1, wherein the rotary transformer core and film have a cylindrical shape. (4) The method for manufacturing a rotary transformer according to claim 1, wherein a recessed portion deeper than at least the thickness of the coil pattern to be transferred is provided in the portion of the surface of the rotary transformer core where the coil pattern is to be transferred.