JPH0666200B2 - Rotating transformer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transformer for non-contact transmission of an electric signal from a rotating side to a fixed side or vice versa, particularly a video. The present invention relates to a rotary transformer for transmitting electronic signals from a rotating magnetic head of a tape recorder or transmitting electric signals to the rotating magnetic head in a non-contact manner.

[Background of the Invention]

Conventionally, in this type of rotary transformer, a ferrite-based material has been used as an opposing magnetic core (hereinafter, simply referred to as a core), and it has been attached to each drum on the rotating side and the fixed side by an adhesive material. However, it is extremely difficult to attach the core with the adhesive to make the thickness of the adhesive uniform between the surface of the drum and the adherend, and the surface of the attached core tilts, causing so-called runout. There was a problem of doing.

As a means for solving such a problem, for example, Japanese Patent Laid-Open No.
There is one in which a screw is fixed as disclosed in Japanese Unexamined Patent Publication No. 120821. The one described in the above publication is one in which a notch is provided in the core, and a screw is passed through the notch to fix the cylinder to a rotating drum, but in order to prevent the core from cracking or cracking due to screw fixing, the screw is used. It has the disadvantage that an elastic material must be used between the core and the core, the core material is also limited in terms of mechanical properties, and one core is used to avoid contact of the screw with the opposite core. It is necessary to increase the outer diameter of, and there is a drawback that the cost becomes high.

[Object of the Invention]

An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to maintain a high surface runout accuracy of the core, to easily manufacture the selection of the core material, and to provide an inexpensive rotary transformer. .

[Outline of Invention]

In order to achieve this object, the present invention is characterized in that an annular fixing member made of a polymer material is used, and the elasticity of the material is skillfully used to accurately fix the core to the cylinder.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of a fixed cylinder (corresponding to the drum) side core portion showing an embodiment in which a rotary transformer according to the present invention is applied to a rotary magnetic head of a video tape recorder. , Referred to as a stator core), 2
Is a polymer material that holds the stator core (eg PBT
Etc.) an annular fixing member (hereinafter referred to as a holder),
3 is a mounting screw, 4a and 4b are coils of a rotary transformer, 5a, 5b, 5c and 5d are relay terminals for connecting the terminals of the coils 4a and 4b, 6 is a first protrusion, and 7 is a second protrusion. 8 is a rotating core (hereinafter referred to as a rotor core), 9
Is a fixed cylinder.

In the figure, the stator core 1 is surrounded from the outer peripheral side by a first protrusion 6 and a second protrusion 7 which are integrally provided in the holder 2, and respectively have an axial direction (axial direction) and a radial direction (radial direction). Is fixed to the fixed cylinder 9 with the screw 3.

The first protrusion 6 and the second protrusion 7 provided on the holder 2
Are 6 and 3 respectively in the illustrated embodiment, but are not limited to this.

FIG. 2 is a view showing the main part of the AA cross section of FIG.
The relay terminal 5a connecting the terminals of the coils 4a and 4b serves as a signal terminal to the outside of the fixed cylinder 9 of the rotary magnetic head device, and is fixed to the holder 2.

The coils 4a and 4b are embedded in the groove provided in the core.

FIG. 3 is a view showing the main part of the BB cross section of FIG. 1,
The operation of fixing the stator core 1 in the axial direction by the first protrusion 6 will be described.

As shown in the figure, the first projection 6 of the holder 2 has a protruding portion that protrudes inward in the radial direction (core 1 side) from the holder 2 and presses the core 1 against the fixed cylinder 9. As described above, the projecting portion is provided so as to contact the upper portion of the peripheral edge of the core 1. In the figure, H indicates a magnetic head virtually.

FIG. 4 is a view showing a main part of a CC cross section of FIG. 1.
The operation of fixing the stator core in the radial direction by the second protrusion 7 will be described.

As shown in the figure, the second protrusion 7 of the holder 2 is provided so as to come in contact with the periphery of the core 1 from the holder 2 in the radial direction thereof, and when the holder 2 is assembled with the core 1, The protrusion 7 of 2 presses the core 1 in the radial direction.

FIG. 5 is a diagram showing a main part of a DD cross section of FIG. 1.
The state where the holder 2 is crimped and fixed to the fixed cylinder 9 by tightening the screw 3 is shown. When the holder 2 is fixed to the fixed cylinder 9 with the screw 3, the first protrusion 6 makes the core 1 axial, and the second protrusion 7 makes the core 1 radial, each of the components of the holder. It is fixed to the fixed cylinder 9 by elastic deformation and is held. Here, since the holder 2 is pressure-bonded and fixed to the fixed cylinder 9, the tightening limit of the screw 3 for this fixing is surely known, and the holder 2 is fixed to the fixed cylinder 9 in a good posture, and the core 1 Is stably fixed to the fixed cylinder 9.

Therefore, the core 1 can be accurately fixed to the fixed cylinder in any of the axial direction and the radial direction, and the core 1 can be selected in a wide range without giving excessive mechanical stress to the core 1. It is possible and easy to manufacture.

〔The invention's effect〕

As described above, according to the present invention, since it is not necessary to perform processing such as a screw hole or a notch for fixing the core, the length of the core can be reduced, and the mechanical stress applied to the core can be reduced. Since only the elastic force of the polymeric material that makes up the holder is applied, an unreasonable force is not applied to the core, and cracks and cracks in the core can be prevented, so the range of selection of core materials can be widened. At the same time, since the core can be fixed to the fixed cylinder with correct flatness, the problem of surface runout is completely eliminated.Furthermore, since the fixing member is crimped and fixed to the fixed drum with a screw, the tightening limit of the screw is determined. The fixing member is crimped to the fixed drum in a good posture, and the magnetic core is fixed to the fixed drum in a stable state. It can be.

[Brief description of drawings]

FIG. 1 is a plan view of a fixed cylinder side core portion showing an embodiment in which the rotary transformer according to the present invention is applied to a rotary magnetic head of a video tape recorder, and FIG. 2 is a main portion of the AA cross section of FIG. FIG. 3, FIG. 3 is a view showing a main part of the BB cross section of FIG. 1, FIG. 4 is a view showing a main part of the CC cross section of FIG. 1, and FIG. 5 is D of FIG. It is a figure which shows the principal part of the -D cross section. 1 ... Stator core, 2 ... Holder, 3 ... Mounting screw, 4a, 4b ... Coil, 5a, 5b, 5c, 5d ...
... relay terminal, 6 ... first protrusion, 7 ... second protrusion, 8 ... rotor core, 9 ... fixed cylinder.

Claims (2)

[Claims] 1. A rotary drum and a fixed drum, each of which has a magnetic core fixed to face each other and to which a coil is attached, and the electric signal is non-contact between the rotary drum side and the fixed drum side. In the rotary transformer adapted to transmit the magnetic field, a discontinuous first protrusion abutting on a plurality of points on the outer peripheral surface of the magnetic core and a discontinuous first protrusion abutting on a plurality of points on the side surface of the magnetic core. The annular fixing member made of a polymer material integrally provided with the protruding portion 2 and the fixing screw hole is crimped to the fixing drum with a screw passing through the fixing screw hole, A protrusion presses the magnetic core in its axial direction to press it against the fixed drum, and a second protrusion presses the magnetic core in its radial direction;
A rotary transformer characterized in that the magnetic core is fixed to the fixed drum. 2. The rotary transformer according to claim 1, wherein the fixing member is provided with a relay terminal for connecting the terminal of the coil.