JPH02246302A - Coil device for rotary transformer and its manufacture - Google Patents

Abstract

PURPOSE:To increase magnetic coupling coefficient, and improve signal transmission efficiency by reducing the distance between the coil conductor of a fixed side and the coil conductor of a rotary side. CONSTITUTION:After adhesive agent 11 is made to flow in a recessed groove 10a with a depth of the same diameter as a coil which is formed on the surface 10a of a lower side core 10 of a ring type, the coil 3 is accommodated and fixed in the recessed groove 10a so as to almost be made flush with the surface 10b. The surface 10b of the lower side core 10 and the coil 3 are commonly ground by the grinding amount corresponding to about 30% of the diameter of the coil 3. As a result, the surface 10c of the lower side core 10 after grinding and the ground surface 3c of coil conductor 3a are made flush with each other; when the lower side core 10 and an upper side core 20 are assembled in the manner in which the surface 10b and a surface 20b face each other, the coil gap of both core bodies can be reduced. Thereby, magnetic coupling coefficient is increased, and signal transmission efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to a coil device for a rotary transformer applied to a video tape recorder, etc., and a method for manufacturing the same.

(Prior Art) A rotary transformer coil device is used for signal transmission in a magnetic recording/reproducing device, such as a video tape recorder.

In recent years, there has been a demand for higher image quality in video tape recorders. It is necessary to aim for this. Therefore, it is preferable that the distance between the coil wound around the stationary core and the coil wound around the rotating core be as small as possible.

As a conventional example, a coil device for a flat plate type rotary transformer is shown in FIG.

FIG. 4(a) is a schematic completed cross-sectional view, and the structure of this coil device is a lower core 1 (for example, a fixed side) formed in a disk shape.
A coil 3 is wound around a concave groove 1a provided in a ring shape on the surface 1b of the upper core 2 (for example, the rotating side) formed in a disc shape having the same diameter as the lower core 1.
After winding the coil 3 in the ring-shaped concave groove 2a, the lower core 1 and the upper core 2 are wound in the concave groove l.
A and 2a are arranged coaxially so that they face each other.

FIG. 4(b) is a detailed sectional view of section A in FIG. 4(a).

A spacer 4 made of an insulator or the like is placed between the concave grooves 1a, 2a of the lower core 1 (fixed side) or the upper core 2 (rotating side) and the coil 3 made of a conductor 3a and an insulating coating 3b. 3 is brought closer to the surfaces 1b and 2b.

Next, another conventional example is shown in FIG. FIG. 5 is a detailed sectional view corresponding to section A shown in FIG. 4(a).

This groove 5a is formed by making the concave grooves 5a and 6a of the lower core 5 (fixed side) or the upper core 6 (rotating side) shallower.

Wind the coil 3 around the surface 5b.

It is approaching the 6b side.

In both the conventional example and other conventional examples, the lower core 1.5 and the upper cores 2 and 6 are coaxially arranged with the gap G kept very small at 0.03 to 0.08all. .

(Problems to be Solved by the Invention) Therefore, since the conventional rotary transformer coil device has the above-described structure, it has the following problems.

In the case of the conventional example shown in FIG. 4, the circumferential surface of the coil 3 is connected to the core 1 by the spacer 4. Since it must be adjusted so that it is flush with surfaces 1'b and 2b of 2, extra assembly man-hours are required. Further, even if such adjustment is made, the conductor 3 will be separated from the surfaces lb and 2b by the thickness of the insulating coating 3b, resulting in poor magnetic coupling and poor signal transmission efficiency.

In the case of another conventional example shown in FIG. 5, since the diameter of the coil 3 varies, the coil 3 of the lower core 5 and the upper core 6
In order to prevent interference with the coil 3, the depth of the concave grooves 5a and 6a must be made deeper than the coil 3. Therefore, the conductor 3a has a surface 5b with a thickness greater than the thickness of the insulating coating 3b.
, 6b, magnetic coupling deteriorates and signal transmission efficiency deteriorates.

An object of the present invention is to provide a coil device for a rotary transformer that can increase the magnetic coupling coefficient and improve signal transmission efficiency by reducing the distance between the conductor of the coil of the fixed side core and the conductor of the coil of the rotating side core. An object of the present invention is to provide a method for manufacturing the same.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the coil device for a rotary transformer of the present invention has a structure in which the conductor of the coil in at least one of the cores and the opposing proximal surface are flush with each other. It is characterized by what it did.

Further, the first manufacturing method of the present invention relating to a coil device for a rotary transformer includes a first step of providing annular grooves in each of the stationary side and rotating side base cores, and then a second step of accommodating the coil in these annular grooves. The present invention is characterized in that, after the step, a third step is provided in which the surface of the base core and the exposed surface of the coil are ground in common to make them flush.

Furthermore, in the second manufacturing method of the present invention relating to a coil device for a rotary transformer, the coil is a coil conductor with an insulating coating, and in the third step, the surface of the base core and the exposed surface of the coil are made common to each other. The coil conductor and the ground surface of the base core are ground to be flush with each other.

(Function) In the rotary transformer coil device of the present invention,
Since the conductor of the coil in at least one of the cores and the opposing proximal surface are flush with each other, by reducing the gap between the core bodies, the gap between the coils of both core bodies can be reduced, so that the magnetic coupling coefficient increases. Signal transmission efficiency is improved.

Further, the first aspect of the present invention of a coil device for a rotary transformer is
In the second manufacturing method, when the exposed surface of the coil with an insulating coating or only a conductor and the surface of the base core are ground in common in the third step, the coil conductor formed by this grinding is The surface is flush with the surface of the base core. As a result, the coil does not protrude from the surface of the base core, so when the base cores are arranged so that the annular grooves face each other, the gap between the base cores can be made small (by doing so, both base cores can be The gap between the coil conductors in the core can be made small, which increases the magnetic coupling coefficient and improves signal transmission efficiency.

(Example) A rotary transformer coil device according to an example of the present invention will be described with reference to the drawings.

FIG. 1(a) is a sectional view of a flat plate type rotary transformer coil device, which is a type of rotary transformer coil device, and FIG. 1(b) is a detailed view of section B in FIG. 1(a).

10 is a lower core (base core) on the stationary side formed in a disk shape, 20 is an upper core (base core) on the rotation side formed in a disk shape, and 10a and 20a are opposing proximal surfaces of the core 10.20. surface 10b.

This is a concave groove (annular groove) having the same diameter and depth as the coil 3 provided in a ring shape in 20b.

As shown in FIG. 1(b), the coil 3 consists of a conductor 3a and an insulating coating 3b applied to the outer periphery of the conductor 3a.
A portion of the conductor 3a is exposed from the insulation coating 3b as an exposed surface 3c. This coil 3 is fixed to the concave grooves 10a, 20a with an adhesive 11, so that the exposed surface 3C of the coil 3 and the surfaces 10b, 20b are flush with each other.

The lower core 10 and the upper core 20 are the surface 10b.

20b facing each other and combined, through hole 10C920
A shaft (not shown) is attached to each of the terminals c, so that 0.
A gap G'71r of 0.03 to 0.08 mm is provided to hold the lower core 10 and the upper core 20 coaxially.

Next, FIG. 2 shows a manufacturing process diagram of a flat plate type rotary transformer coil device as a first embodiment of the method for manufacturing a rotary transformer coil device according to the present invention.

FIG. 2(a) is a sectional view showing the first step.

Surface 1 of the lower core (base core) 10 formed in a disk shape
Concave groove (annular groove) 1 having the same diameter depth as the coil at 0b
0a is provided in a ring shape.

FIG. 2(b) is a detailed sectional view at part 0 (FIG. 2(a)) showing the second step. 3 is a conductor 3a and this conductor 3a
It is a coil consisting of an insulating coating 3b applied to the outer periphery of the coil. After the adhesive 11 is poured into the concave groove 10a, the coil 3 is placed over the adhesive 11, and then the adhesive 11 is cured to fix the coil 3 in the concave groove 10a. In this state, the exposed surface of the coil 3 and the surface 10b are substantially flush.

Figure 2 (C) shows the third step C4! fJ (same figure (a)
) is a detailed cross-sectional view. As shown in FIG. 2(b), the surface 10b of the lower core 10 and the coil 3 are connected to each other.
Commonly ground with a grinding amount equivalent to about 30% of the diameter of. Then, the surface 10c of the lower core 10 after grinding and the ground surface 3c of the coil conductor 3a become flush with each other.

The lower core 10 and the upper core 20 are the surface 10b.

20b are assembled facing each other, and the assembly is roughly completed as shown in the cross-sectional view of FIG. 1(a).

Next, a method for manufacturing a coaxial type rotary truss coil device will be described as a second embodiment of the method for manufacturing a rotary transformer coil device according to the present invention.

FIG. 2 is a schematic sectional view of this coaxial type rotary truss coil device after completion.

The first to third steps are omitted because they can be manufactured in the same manner as the method for manufacturing the flat plate type rotary transformer m-coil device, as shown in FIG.

Reference numeral 11 denotes an inner core (base core) formed in a cylindrical shape, for example on the stationary side, and 21 is an outer core (base core) on the rotation side, formed in a cylindrical shape and arranged outside the inner core 11.
It is.

In the first step, a concave groove (annular groove) 11a is provided on the outer circumferential surface (surface) 11b of the inner core 11, and a concave groove (annular groove) 21a is similarly provided on the inner circumferential surface (surface) 21b of the outer core 21.

Next, in a second step, the coil 3 (see FIG. 2(b)) is housed in the concave grooves 11a and 21a.

Then, in the third step, the circumferential surfaces 11b, 21b and the coil 3 are ground in common, as shown in FIG. 2(C), so that the conductor of the coil 3 and the curved surfaces 11b, 21b are flush with each other.

Finally, a shaft (not shown) is installed in the through hole 11c of the inner core 11, and a bearing (not shown) is installed in the outer circumferential surface 21c of the outer core 21. ,0
The inner core 11 and the outer core 21 have a gap G of 8a+.
and are held coaxially.

As described above, the device and the method for manufacturing the same according to the embodiment of the present invention are configured, so the coil device for a flat plate rotary transformer and the method for manufacturing the same according to the embodiment have the following effects.

(1) Compared to the conventional method, only the third step of grinding the coil 3 and the surface 10b of the lower core 10 or the upper core is simply added, so magnetic coupling is easily increased and signal transmission efficiency is improved. can be achieved.

(b) Since the depth of the concave groove 10a does not require high precision, the lower core 10 or the upper core can be manufactured easily.

(C) Since the distance between the conductors of the lower core and the upper core is constant by keeping the gap between the lower core and the upper core constant, the signal transmission efficiency is stabilized.

(d) In the third step, the gap between the conductor 3C of the coil 3 of the lower core 10 and the coil 3 of the upper core becomes smaller, so that the magnetic coupling coefficient increases and signal transmission efficiency can be improved.

(e) Even if the conductor 3a of the coil 3 is ground, the cross-sectional area required for current capacity can be secured.

Also, in the method of manufacturing the coil device for a coaxial type rotary transformer of the second embodiment, magnetic coupling increases and the signal transmission efficiency is improved, similar to the method of manufacturing the coil device for a flat plate type rotary transformer of the first embodiment. Improvements can be made.

Although the embodiments have been described above, the present invention is not limited thereto, and various modifications can be made without changing the gist thereof.

For example, in this example, a coil with an insulating coating applied to the conductor was used, but even if only the coil conductor is used, by maintaining insulation between the coil conductors and between the coil conductor and the base core,
A similar effect can be obtained. That is, in FIG. 2, by using an insulating adhesive 11, insulation can be maintained between the coil conductors and between the coil conductor and the base core.

Furthermore, an insulating sheet may be interposed between the base core and the coil conductor.

In addition, the flat plate type rotary roller coil device shown in Fig. 1 uses a coil with exposed conductors in both cores, but it uses a coil in only one core with no exposed conductor in the other core. Similarly, the magnetic coupling coefficient can be improved.

[Effects of the Invention] Since the present invention is configured as described above, it produces the following effects.

In the first aspect, by reducing the gap between the base cores, the gap between the coil conductors can be reduced.

Therefore, the magnetic coupling coefficient becomes large and signal transmission efficiency can be improved.

Claim 2. 3.4 and 6, the conductor of the coil and the surface of the base core become flush with each other in the third step, so by reducing the gap between the base cores,
The gap between coil conductors can be reduced. Therefore, the magnetic coupling coefficient becomes large and signal transmission efficiency can be improved.

In claim 5, the conductor of the coil of the base core and the surface of the base core are flush with each other while ensuring the necessary cross-sectional area of the current capacity of the conductor of the coil, so as described in claims 2.3 and 4. Similar to the effect in , the magnetic coupling coefficient increases and signal transmission efficiency can be improved.

[Brief explanation of drawings]

FIG. 1(a) is a schematic sectional view of a flat plate type rotary transformer coil device, which is an embodiment of the rotary transformer coil device according to the present invention, and FIG. 1(b) is a detail of section A in FIG. 1(a). 2 are manufacturing process diagrams of a coil device for a flat plate type rotary transformer according to a first embodiment of the coil device for a rotary transformer according to the present invention, in which FIG. 2(a) shows the first step, and FIG. ) is the second process drawing, Figure 2(c) is the third process drawing,
FIG. 3 is a schematic completed diagram of a coil device for a coaxial rotary transformer according to the second embodiment, FIG. 4(a) is a schematic completed diagram of a conventional coil device for a flat plate rotary transformer, and FIG.
b) is a detailed sectional view of section A in FIG. 4(a), and FIG.
FIG. 3 is a detailed cross-sectional view corresponding to section A in FIG. 3... Coil, 3a... Conductor, 3b... Insulating coating, 10... Lower core (fixed l!1 base core) (fixed side core), 10a, 20a... Concave groove (annular groove), 1
0b, 20b... Surface (opposing proximal surface), 20... Upper core (H modulation base core) (rotating side core). (b) Figure 2 (b) Figure 2

Claims (6)

[Claims] (1) In a coil device for a rotary transformer, in which a coil is housed in annular grooves disposed facing each other in opposing proximate surfaces of a stationary side core and a rotating side core, the conductor of the coil in at least one of the cores and the opposing proximate A coil device for a rotary transformer, characterized in that its surfaces are flush with each other. (2) A method for manufacturing a coil device for a rotary transformer, which includes a first step of providing annular grooves in each of the fixed side and rotating side base cores, and a second step of storing the coil in these annular grooves. A method for manufacturing a coil device for a rotary transformer, characterized in that, after the second step, a third step is provided in which the surface of the base core and the exposed surface of the coil are ground in common to make them flush. (3) The coil is a coil conductor with an insulating coating, and in the third step, the surface of the base core and the exposed surface of this coil are ground in common, so that the coil conductor and the ground surface of the base core are flat. 3. The method for manufacturing a rotary transformer coil device according to claim 2. (4) The method for manufacturing a rotary transformer coil device according to claim 2, wherein the coil is made of only a coil conductor. (5) The amount of grinding in the third step is set to 10 of the coil diameter.
5. The method for manufacturing a rotary transformer coil device according to claim 2, 3 or 4, wherein the ratio is 50% to 50%. (6) Claim 2, 3, 4 or 5, wherein the third step is provided on at least one of the base core side, which is a fixed side or a rotating side.
A method of manufacturing the described rotary transformer coil device.