JPH08186044A - Rotary transformer and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a rotary transformer suitable for reducing the thickness, and a manufacturing method thereof, in which excellent magnetic coupling can be realized at coil parts provided at the rotor part and the stator part while facilitating the setting of inductance. CONSTITUTION: The rotary transformer comprises one or more than one spiral conductor 3 having rectangular cross-section, a magnetic substrate having recesses for receiving the spiral conductors 3 same in number as the spiral conductors 3, and a nonmagnetic insulator interposed between the spiral conductor 3 and the magnetic substrate. The rotary transformer comprises rotor part and stator part and the spiral conductor 3 is flush with the magnetic body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transformer and a manufacturing method thereof, and more particularly to a rotary transformer having a coil portion having a spiral conductor pattern in the vicinity of an air gap between a rotor portion and a stator portion.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
In the rotor part and the stator part of the rotary transformer, a ferrite substrate is provided with a groove and a copper wire is embedded to form a coil part. However, in this method, in consideration of the wire diameter of the copper wire (about 80 to 100 μm) and the float when the copper wire is stored in the groove, a groove having a depth of about 300 μm is required, which leads to downsizing and thinning. It was difficult.

Further, as shown in FIG. 3 ((a) is a perspective view of a rotor portion or a stator portion, and (b) is an enlarged cross-sectional view of the portion B), the conductor layer is coated. It is known that the above resist layer is etched, followed by etching treatment to form the spiral conductor 3, and then plating treatment (Japanese Patent Laid-Open No. 58-12315). FIG.
Shows a manufacturing process thereof, (a) shows a base material to be a rotor part or a stator part, the nonmagnetic insulating layer 8 and the conductor layer 7 are formed in the recess of the ferrite substrate, and the upper surface thereof is a resist layer. It is coated with 9. This resist layer 9
Are etched as shown in (b), followed by (c),
By performing the etching process in the order of (d) and removing the resist layer 9, the spiral conductor 3 is formed.

Thereafter, a plating process is performed to increase the thickness of the spiral conductor 3 and reduce its resistance value. However, even if the plating process is performed, the constriction 10 formed on the side surface portion of the spiral conductor 3 during the etching process cannot be complemented. Therefore, since the conductor width of the formed spiral conductor 3 is not constant in the thickness direction and the pattern accuracy is not good, it is difficult to obtain a desired inductance value. There is also a problem that crosstalk occurs between adjacent patterns in the spiral conductor.

On the other hand, as shown in FIG. 5 (a), there is known a structure in which a plurality of arc-shaped conductors 3 are superposed in a magnetic body via a non-magnetic insulator to form a coil portion (Japanese Patent Application No. Hei. -248
No. 803). However, in this case, as shown in (b),
As compared with the case where a coil portion is provided with a spiral (planar) conductor, magnetic coupling is not good when these coil portions are opposed to each other, and it is difficult to reduce the thickness of the rotary transformer.

According to the present invention, the above problems are solved, and a spiral conductor pattern is accurately and uniformly formed in the vicinity of the air gap between the rotor portion and the stator portion, so that the magnetic coupling of the coil portion is improved. It is an object of the present invention to provide a rotary transformer which can easily set an inductance value and is suitable for thinning, and a manufacturing method thereof.

[0007]

According to a first aspect of the present invention, there is provided a rotary transformer according to claim 1, wherein one or more spiral conductors having a rectangular cross section and recesses for accommodating the spiral conductors are provided in the same number as the spiral conductors. A body substrate and a non-magnetic insulator interposed between the spiral conductor and the magnetic substrate, and the surface of the spiral conductor portion is the same as the surface of the magnetic body. And a rotor part and a stator part.

According to a second aspect of the present invention, there is provided a method for manufacturing a rotor for a rotary transformer and a stator, wherein one or more recesses are provided in a substrate made of an unsintered magnetic material, and an unsintered non-magnetic insulating material is buried in each recess. A step of firing both of them at the same time to make them into a magnetic substrate and a non-magnetic insulator, a step of forming a spiral groove in the non-magnetic insulator, and a conductor on the entire surface of the magnetic substrate provided with the groove. The step of forming a layer and the step of removing conductors other than the inside of the groove to form the same number of spiral conductors as the recesses.

[0009]

According to the rotary transformer of claim 1,
One or more spiral conductors having a rectangular cross section, a magnetic substrate having the same number of recesses for accommodating the spiral conductors as the spiral conductors, and interposed between the spiral conductors and the magnetic substrate. Since the surface of the spiral conductor is the same as the surface of the magnetic body, the rotor and the stator are characterized by the following effects. Have. (1) Since the coil portion is formed in the vicinity of the air gap between the rotor portion and the stator portion, the coupling coefficient of the opposing coil portions is improved.

(2) Since the nonmagnetic insulator is embedded in the lower surface and the side surface portion of the spiral conductor, the interference of magnetic flux between adjacent patterns in the spiral conductor is suppressed.

(3) Since the surface of the magnetic substrate on which the spiral conductor is provided is flat (no groove is formed), the mechanical strength of the magnetic substrate is improved.

(4) Since the conductor pattern is formed in a plane, it is easy to reduce the thickness of the rotary transformer.

According to the method of manufacturing the rotor and the stator for the rotary transformer of claim 2, one or more recesses are provided in the substrate of the unsintered magnetic material, and the unsintered non-magnetic insulating material is also embedded in the recesses. , A step of firing both of them at the same time to make them a magnetic substrate and a non-magnetic insulator, a step of forming a spiral groove in the non-magnetic insulator, and a whole surface of the magnetic substrate on which the groove is provided. Since it comprises a step of forming a conductor layer and a step of removing the conductor other than the inside of the groove to form the same number of spiral conductors as the recesses,
It has the following effects. (1) Since a uniform conductor pattern can be formed with high accuracy, it becomes easy to obtain a desired inductance value.

(2) Since the coil portion can be formed near the air gap between the rotor portion and the stator portion,
The coupling coefficient of the facing coil portions can be improved.

(3) Since the nonmagnetic insulator can be embedded in the lower surface and the side surface portion of the conductor pattern, the mutual interference of magnetic flux between the adjacent conductor patterns can be suppressed. Moreover, the mechanical strength of the magnetic substrate is improved.

[0016]

1 (a) is a perspective view showing a rotor portion or a stator portion constituting a rotary transformer of the present invention.
(B) is an enlarged view of the cross section of the portion A shown in (a), in which a coil portion composed of a spiral conductor pattern is formed on a ferrite substrate via a non-magnetic insulator. When this coil portion is viewed from above, as many coil portions as the number of channels (the number of signal paths) are formed as shown in (c). (FIG. 1 shows a rotary transformer having two channels.) By making the coil portions of the rotor portion formed as described above face each other through an air gap, the coil portions of each channel are mutually It is magnetically coupled and acts as a transformer.

The process of forming the coil portion, which is a spiral conductor pattern, on the ferrite substrate will be described below with reference to FIG. 2 and the structure of the rotary transformer will be described. 1A to 1D are enlarged views of the cross section of the portion A in FIG. 1A.

As shown in FIG. 2A, the ferrite substrate 2 serving as the rotor portion or the stator portion has a recess 5 having a depth of 20 μm for providing a coil for each channel. The nonmagnetic insulator 4 is embedded. The non-magnetic insulator 4 (non-magnetic ferrite, foresterite (dielectric), etc.) is simultaneously fired when the ferrite substrate 2 is fired.

The non-magnetic insulator 4 is provided with a spiral groove 6 having a width of about 40 to 50 μm as shown in FIG. 2B by a treatment such as sandblast (powder beam), laser, etching and the like.

Next, as shown in FIG. 2 (c), the entire surface of the ferrite substrate 2 having the spiral groove 6 is subjected to treatments such as plating, vapor deposition, and sputtering to form the conductor layer 7. (Cu, Ag, Ni, Au, Pt, etc.) are formed. Subsequently, as shown in FIG. 2D, the surface is polished so that the conductor remains only inside the groove 6 (the conductors other than the conductor inside the groove 6 are removed) to form the spiral conductor 3 and the coil portion. To do.

As is apparent from the above manufacturing process, the upper surface of the coil portion provided on the ferrite substrate is formed on the same surface as the upper surface of the ferrite substrate, and the spiral conductor forming the coil portion is planar. It is formed in two dimensions. Therefore, when the rotor part and the stator part are opposed to each other, the coil parts of both parts can be brought closer to each other, so that the coupling coefficient between the opposed coil parts can be improved. Moreover, since the conductor pattern is formed in a plane, a thin rotary transformer can be configured.

Further, since the nonmagnetic insulator is embedded in the lower surface and the side surface portion of the conductor pattern, crosstalk between adjacent patterns in the spiral conductor can be suppressed.

By forming the coil portion for the channel concentrically with respect to the rotating shaft by the above-described manufacturing process, the rotor portion and the stator portion forming the rotary transformer can be obtained. Further, a protective layer made of resist resin or the like may be provided to prevent corrosion of the coil conductor and ensure insulation.

[0024]

Since the present invention is configured as described above, it has the following effects.

(1) Since the coil portion is formed in the vicinity of the air gap between the rotor portion and the stator portion, the coupling coefficient of the opposing coil portions can be improved.

(2) Since the non-magnetic insulator is embedded in the lower surface and the side surface portion of the spiral conductor, it is possible to suppress the interference of magnetic flux between the adjacent patterns in the spiral conductor.

(3) Since the surface of the magnetic substrate on which the spiral conductor is provided is flat (no groove is formed), the mechanical strength of the magnetic substrate can be improved.

(4) Since the conductor pattern is formed in a plane, the rotary transformer can be easily thinned.

(5) Since a uniform conductor pattern can be formed with high accuracy, it becomes easy to obtain a desired inductance value.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a rotary transformer of the present invention.

FIG. 2 is an explanatory view showing a manufacturing process of a rotary transformer of the present invention.

FIG. 3 is an explanatory diagram showing a conventional rotary transformer.

FIG. 4 is an explanatory view showing a manufacturing process of a conventional rotary transformer.

FIG. 5 is an explanatory diagram showing a conventional rotary transformer.

[Explanation of Codes] 1 coil part 2 ferrite substrate 3 spiral conductor 4 non-magnetic insulator 5 recess 6 groove 7 conductor layer 8 non-magnetic insulator layer 9 resist layer 10 constriction 11 arc-shaped conductor

Claims (2)

[Claims] 1. A spiral conductor having one or more rectangular cross sections, a magnetic substrate having the same number of recesses for accommodating the spiral conductor as the spiral conductor, the spiral conductor and the magnetic substrate. A rotary transformer comprising a rotor part and a stator part, which is made of a non-magnetic insulating material interposed between the rotor and the stator, and the surface of the spiral conductor is the same as the surface of the magnetic material. 2. A substrate of unfired magnetic material is provided with one or more recesses, and an unfired non-magnetic insulating material is similarly embedded in the recesses, both of which are fired at the same time to form a magnetic substrate. A step of forming a non-magnetic insulator, a step of forming a spiral groove in the non-magnetic insulator, a step of forming a conductor layer on the entire surface of the magnetic substrate provided with the groove, and a conductor other than the inside of the groove. And forming the same number of spiral conductors as the recesses, the method for manufacturing a rotor and a stator for a rotary transformer.