JPS60216516A - Forming method of winding for rotary transformer - Google Patents

Abstract

PURPOSE:To obtain a rotary transformer, characteristics thereof hardly disperse, simply by digging a concentric circular beltlike region for forming a winding to the surface of a discoid transformer core, burying a conductive metallic layer into the region through an insulating layer and forming the metallic layer to a spiral winding through fine trimming. CONSTITUTION:A circular winding groove 2 having predetermined width and depth is dug concentrically to the surface of a discoid transformer 1 consisting of ferrite, silicon steel, nickel steel, permalloy, etc., the base and side circumferential surface of the groove are coated with an insulating layer 5, and a thin conductive metallic layer 6 composed of silver, copper, etc. is buried on the insulating layer 5. A core 1 is placed on a turntable having high accuracy, the metallic layer 6 is irradiated by thin laser beams 8 from a laser trimming device 7 as a spiral locus while turning the core 1, a separating groove 9 is formed to the metallic layer 6, and the metallic layer 6 is left spirally. Accordingly, a microminiature rotary transformer is obtained with high accuracy, and the transformer is proper to a rotary head type VTR, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary transformer used in a rotary head type VTR, and more particularly to a winding forming method for winding a disk-shaped transformer core.

FIG. 1 shows a schematic configuration of a conventional rotary transformer.

The rotary transformer has two disc-shaped transformer cores 1a and 1b, which are arranged close to each other on the same axis and facing each other,
One is the stator and the other is the rotor. transformer core 1
Two circular winding grooves 2a and 2b, 2c and 2d with different diameters are formed on the opposing surfaces of a and 1b, and windings 3a, 3b, 3c and 3d are respectively formed in each winding groove. It is installed. This example is a two-channel rotary transformer, in which windings 2a and 20 are electromagnetically coupled, and windings 3b and 3d are electromagnetically coupled.

In the conventional manufacturing method of a rotary transformer of this type of structure, each of the windings mentioned above is prefabricated in the form of a flat air-core coil using a special winding device. This air-core coil is fixed in the winding groove of the transformer core with an adhesive.

In this manufacturing method, since the flat air-core coil is very easily deformed, it must be handled with care, which not only impairs assembly work but also has a negative effect on transformer performance. If the air-core coil is fixed to the transformer core while being deformed, an error occurs in the position of the winding with respect to the core, which causes variation in electromagnetic coupling characteristics between the rotor side and the stator side. Furthermore, the use of adhesive to fix the air-core coil to the core is also a major cause of poor assembly workability and transformer performance. Applying adhesive evenly within the small winding grooves is extremely troublesome and can easily cause problems such as the adhesive spilling out of the grooves or dust adhering to the adhesive. For this reason, generally speaking, the width and depth of the winding groove are made sufficiently large compared to the air-core coil installed there.
It gives me some leeway. However, when the width of the winding groove is increased, alignment of the air-core coil with respect to the groove becomes a problem.
Variations in characteristics occur due to positional errors as described above. In addition, when the depth of the winding groove is increased, the distance from the core surface to the winding in the groove (retraction l) increases, and the interval between the windings of the rotor and stator increases. This is extremely undesirable because it greatly reduces the coupling efficiency of electromagnetic coupling between both windings.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide a rotary transformer that can mass-produce high-performance rotary transformers with little variation in characteristics at a high yield, stably, and inexpensively through a simple manufacturing process. An object of the present invention is to provide a winding forming method.

In order to achieve the above object, the present invention forms a thin conductive metal layer on the surface of a transformer core at least in a circular band-shaped region concentric with the core, and uses a fine trimming device such as a laser trimming device to trim this exclusive layer. A separation groove is formed by removing it linearly, and this separation groove is carved in a spiral shape concentric with the core. As a result, a spiral winding is formed using the conductive metal layer remaining between the spiral separation grooves.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

First, as shown in FIG. 2, a disk-shaped transformer core 1 made of a magnetic material such as ferrite, silicon steel, nickel steel, or permalloy is prepared. Circular winding grooves 2 having a predetermined width and depth are concentrically formed on the surface of the transformer core 1. This example is for two channels, and two winding grooves 2°2 with different diameters are provided.

First, as shown in FIG. 3(A), in the transformer core 1 described above, an insulating layer is formed on the entire bottom surface and side peripheral surface of the winding groove 2.
Next, as shown in FIG.
Form I6 uniformly.

The insulating layer 5 can be easily formed, for example, by applying 1' an insulating paint to the inner surface of the winding groove 2.

The conductive stand jIwII6 is made of good quality materials such as silver and copper! An electrically conductive metal is formed on the surface of the insulation 115 by vapor deposition or baking. 1 on the flat bottom part of the winding groove 2! Electric metal 6
The uniform formation of can be easily achieved using automated equipment. At this time, the conductive base 1a layer 6
The thickness of the transformer core 1 is such that its surface is slightly recessed from the surface of the transformer core 1.

Next, as shown in FIG.
(not shown), and the transformer core 1 is rotated at a predetermined speed as shown by arrow a around its center. A laser trimming device 7 is installed above the transformer core 1 rotated in this manner, and a thin laser beam 8 generated from the laser trimming device 7 is irradiated onto the conductive table 6 in the winding groove 2. This laser trimming device 7 is provided with a highly accurate beam scanning function, and scans the laser beam 8 in the radial direction of the transformer core 1 from the outside to the inside as shown by the arrow at a predetermined speed.

Due to the combination of the rotation of the transformer core 1 and the scanning of the laser beam 8, the irradiation point of the laser beam 8 draws a spiral trajectory concentric with the winding groove 2. conductive metal layer 6
is very thin, and when the laser beam 8 is irradiated, the irradiated portion of the metal layer is removed and the underlying insulating layer 6 is exposed.

Since the irradiation point of the laser beam 8 draws a spiral trajectory, the conductive metal layer 6 is linearly removed along the trajectory, forming a spiral separation groove 9 as shown in FIG. This continuous spiral separation groove 9. The conductive base 6 is trimmed, so that the conductive metal layer 6 remains in the form of one continuous spiral winding. In this way, the winding groove 2 of the transformer core 1
A winding is formed within.

As is well known, extremely fine trimming can be performed using a laser trimming device. For example, if the pitch of the spiral separation grooves 2 is 2 μm, the width of the separation grooves 2 is 1 μm, and the width of the metal 116 remaining between the separation grooves 2 is 1 μm, the width of the winding groove 2 is about 1 am+. It is possible to form windings with as many as 500 turns. Furthermore, such highly accurate processing can be performed at high speed using automated equipment.

Since high-precision machining can be performed as described above, the winding groove 2
There is no error in the position of the windings relative to each other, and it is easy to bring the surface of the windings as close as possible to the surface of the transformer core 1. Therefore, when the rotor side and the stator side are combined, variations in characteristics due to positional errors between both windings are eliminated, and the coupling coefficient between both windings can be made very large. Furthermore, it is easy to realize an ultra-compact rotating transformer while maintaining high precision.

Although the laser trimming device is an excellent device that can perform extremely fine processing, other fine trimming devices,
For example, it is also possible to use a sandblasting and trimming device. Further, when the transformer core is made of a magnetic material having a high specific resistance such as nickel rank, the above-mentioned insulating layer 5 for electrically insulating the windings and the core may not be provided.

Further, in the above embodiment, the transformer core has a winding 1fAm, and the winding is formed in the winding groove.
The invention is not limited to this structure. The structure of a rotating transformer is such that the transformer core of either the rotor or the stator does not have a winding groove, but the winding is provided on the flat surface of the core, or even an annular convex part is used instead of the winding groove. There is also known a structure in which a core is provided with a winding on the apex surface of the convex portion. The winding forming method of the present invention can be applied to a rotary transformer having this type of structure in the same manner as described above.

As described above in detail, according to the present invention, high-performance rotary transformers with little variation in characteristics can be mass-produced at low cost through simple processes using relatively simple production equipment.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the schematic configuration of a conventional rotary transformer.
2(A) and 2(B) are a plan view and a sectional view showing an example of a transformer core to which the method of the present invention is applied, and FIG. 3(A)
)(B) is an explanatory diagram of the insulating pattern forming step and the six electric metal layer forming steps according to one embodiment of the method of the present invention, FIG. 4 is a schematic perspective view of the same conductive metal layer trimming step, and FIG. FIG. 2 is a partially enlarged view showing an example of a rotary transformer in which windings are formed by the method of the invention. 1 - Transformer core 2 Winding groove 5 Insulating layer 6-1 Gold JII layer 7 Laser trimming device 8 Laser beam 9 Separation groove Patent applicant Fuji Electric Kagaku Co., Ltd. Agent Patent Attorney - Ken Iro Axis Box 1 Figure 2 (A)

Claims (1)

[Claims] (1) A step of forming a thin S conductive metal layer on the surface of a disc-shaped transformer core at least in a circular band-shaped region concentric with the core, and a separation groove formed by linearly removing the conductive metal layer using a fine trimming device. forming a spiral winding of a rotary transformer, the method comprising forming a spiral winding with the conductive metal layer remaining between the spiral separation grooves; Method.