JPH0869933A - Rotary transformer - Google Patents

Abstract

PURPOSE: To improve the electrical characteristic of a rotary transformer and, at the same time, to prevent the entrance of dust, etc., into the gap of the rotary transformer by determining the gap distance, considering the rotary transformer as a single unit and reducing the width of the gap section. CONSTITUTION: In a rotary transformer in which a rotor 2 and stator 1 face to each other with a very narrow gap in between, the rotor 1 and stator 2 are united in one body with a ball bearing 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transformer used in a rotary magnetic head device such as a video tape recorder (hereinafter referred to as VTR) or a digital audio tape recorder (hereinafter referred to as DAT).

[0002]

2. Description of the Related Art A rotary transformer is widely used as a connecting means for transmitting a signal obtained by a magnetic head provided on a rotating side to a circuit on a fixed side in a rotating magnetic head device such as a VTR or a DAT. There is.

Generally, in a rotary transformer, a coil formed, for example, in an annular shape is fitted and disposed in each winding groove provided concentrically in accordance with the number of channels on one side surface of a substantially disk-shaped magnetic core. The rotor and the stator are formed as described above, and these are opposed to each other with a minute gap therebetween.

Then, by electromagnetic coupling between each coil of the rotor provided on the rotating side and the stator provided on the fixed side, a magnetic head connected to the rotor is connected to a reproducing circuit connected to the stator, for example. , Video signals, digital audio signals, etc. are transmitted.

[0005]

By the way, in the rotary transformer, the rotor and the stator are handled as separate parts, and when the rotor and the stator are incorporated in the rotary drum, the distance between the rotor and the stator facing each other (hereinafter referred to as the gap) is set to a predetermined value. I am trying to do it. The gap largely depends on the electrical characteristics of the rotary transformer, and the smaller the gap, the better the electrical characteristics.

As described above, if the gap is determined when the rotary transformer is assembled, the characteristics cannot be determined by the rotary transformer alone, and the characteristics of the rotary transformer are influenced by the usability on the drum side.

Further, since the facing surface of the rotary transformer is exposed until the drum is assembled, defects such as hit noise are apt to occur due to adhesion of dust and the like. Further, since the lower limit of the gap is determined depending on the assembly accuracy of the drum, it is not possible to make the gap extremely narrow, which is disadvantageous in terms of electrical characteristics.

Therefore, the present invention has been proposed in view of such a conventional situation, and the gap can be determined as a single rotary transformer, the electric characteristics are improved by narrowing the gap, and the gap portion is formed. It is an object to provide a rotary transformer that can prevent the entry of dust and the like.

[0009]

A rotary transformer according to the present invention has a structure in which a rotor and a stator are arranged to face each other with a minute gap. In this rotary transformer, the rotor and the stator are integrated by ball bearings in order to determine the gap and fix the electrical characteristics by the rotary transformer alone.

Specifically, the rotor is fixed to the outer ring of the ball bearing, and the stator is fixed to the inner ring of the ball bearing. Also, the ball bearings are provided above and below the rotary transformer or on either one of them. The ball bearings may be fixed by an adhesive or may be fitted to the rotor and the stator.

[0011]

In the rotary transformer according to the present invention,
Since the rotor and the stator are integrated by the ball bearing, this ball bearing determines the gap between the rotor and the stator.
The gap accuracy is stable, and the electrical characteristics of the rotary transformer are fixed.

As described above, since the gap is determined as a single rotary transformer, the electrical characteristics can be improved by narrowing the gap. In addition, since the rotor and the stator are integrated by the ball bearing in the state before being assembled in the drum, it becomes difficult for dust and the like to be mixed into the gap portion, and a hit noise defect is avoided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

Embodiment 1 The rotary transformer of this embodiment is an example in which a ball bearing is attached to one side surface of the stator and the rotor in the axial direction.

As shown in FIG. 1, such a rotary transformer is a so-called vertical rotary transformer in which a stator 1 and a rotor 2 each having a cylindrical shape are coaxially arranged to face each other inwardly and outwardly.

Each of the stator 1 and the rotor 2 is formed by kneading a magnetic powder such as ferrite in a binder, hardening the mixture by pressing, firing and polishing this. The stator 1 and the rotor 2 are formed as cylindrical bodies having different diameters.

The rotor 2 is formed as a cylindrical body having a diameter larger than that of the stator 1, and the stator 1 is arranged inside of the rotor 2 so as to face each other with a predetermined gap T, which is a predetermined facing distance. The rotor 2 rotates around the outer periphery of the stator 1 fixed by a support shaft (not shown).

Further, the stator 1 and the rotor 2 are respectively provided with coil disposing grooves 3 and 4 formed as annular grooves having a substantially U-shaped cross section for disposing coils. Coil arrangement groove 3 provided in the stator 1
Are formed on the outer wall surface facing the rotor 2, and are provided at predetermined intervals in the axial direction.

In this embodiment, since there are three channels, they are provided in the central portion of the stator 1 and in the vicinity of the upper and lower ends sandwiching this.

On the other hand, the coil mounting groove 4 provided in the rotor 2 is provided on the inner wall surface facing the stator 1 at a position facing the coil mounting groove 3 provided in the stator 1. That is, the coil arrangement grooves 4 provided in the rotor 2 are also provided in the same number as the coil arrangement grooves 3 provided in the stator 1.

And, in these coil arrangement grooves 3 and 4,
The coils 5 and 6 each having a substantially circular cross section are wound a predetermined number of times. The coils 5 and 6 are fixed to the coil arrangement grooves 3 and 4 with an adhesive or the like so as not to fall off from the coil arrangement grooves 3 and 4.

In particular, in this embodiment, the stator 1
And the rotor 2 are integrated by a ball bearing 7. That is, a ball bearing 7 including a ball 8 made of a steel ball and an inner ring 9 and an outer ring 10 provided on both sides of the ball 8 is attached to one end faces of the stator 1 and the rotor 2 in the axial direction.

The stator 1 has one side surface 9a of the inner ring 9.
It is fixed on the top with an adhesive or the like. On the other hand, the rotor 2 is also fixed on one side surface 10a of the outer ring 10 by an adhesive or the like.

In this way, if the stator 1 and the rotor 2 are fixed to the ball bearing 7 in a state where they are opposed to each other with a predetermined gap T, the electrical characteristics can be determined as a single rotary transformer. In other words, since the electrical characteristics of the rotary transformer have already been determined in a state before being incorporated in the drum, the gap variation due to the work of incorporating the rotary transformer does not occur, and the problem of variation in the electrical characteristics of the rotary transformer can be solved. Moreover, since the gap T can be determined in advance, the gap can be narrowed from the beginning, and improvement in electrical characteristics can be expected.

Embodiment 2 The rotary transformer of this embodiment is an example in which ball bearings 7 are mounted on the upper and lower sides.

That is, as shown in FIG. 2, ball bearings 7 are attached to the upper and lower end faces in the axial direction of the rotary transformer shown in FIG. 1 described in the first embodiment.

By providing the ball bearings 7 on the upper and lower end surfaces of the rotary transformer, the problem of interference between the stator 1 and the rotor 2 due to the looseness of the ball bearings 7 is eliminated as compared with the case where the ball bearings 7 are provided on only one side. it can. Further, the accuracy of the gap can be made more stable, and the variation in the electrical characteristics of the rotary transformer can be reduced. Further, by providing the ball bearings 7 on the upper and lower sides, it is possible to reliably prevent dust from adhering to the gap.

Embodiment 3 The rotary transformer of this embodiment is one in which the ball bearing 7 is integrated by fitting it to the stator 1 and the rotor 2.

That is, the stator 1 and the rotor 2 are provided with recesses 11 and 12 for fitting with the ball bearings 7, and the ball bearings 7 are fitted into the recesses 11 and 12, so that the ball bearings 7 are fixed to the rotor 1 and the rotor 1. It is integrated with 2.

As described above, when the ball bearing 7 is fitted and integrated with the stator 1 and the rotor 2, the centering work of the ball bearing 7, the stator 1 and the rotor 2 becomes easy. Therefore, by simply aligning and mounting the ball bearings 7 in the recesses 11 and 12 of the stator 1 and the rotor 2, the centering work of the ball bearings 7 and the stator 1 and the rotor 2 can be easily performed.

Embodiment 4 This embodiment is an example of a so-called flat type rotary transformer in which a disk-shaped stator and a rotor are arranged to face each other with a predetermined gap.

As shown in FIG. 4, the flat rotary transformer is constructed by disposing a disk-shaped stator 13 and a rotor 14 so as to face each other with a predetermined gap T therebetween.

Both the stator 13 and the rotor 14 have coils 15 and 1 each having a substantially circular cross section on the surfaces facing each other.
A coil disposing groove 1 having a substantially U-shaped cross section for disposing 6
7, 18 are formed. This coil arrangement groove 17, 1
In the coil 8, coils 15 and 16 in which wire rods are preliminarily formed into an annular shape are arranged. The coils 15 and 16 are fixed with an adhesive or the like to prevent them from coming off.

Then, the stator 13 and the rotor 1
4 is integrated with the ball bearing 7 by fitting with the ball bearing 7. That is, the circular center holes 19 and 20 provided at the centers of the stator 13 and the rotor 14 are provided with recesses 21 and 22 that fit into the ball bearings 7 at the peripheral edges of the openings. Then, the inner ring 9 and the outer ring 10 are provided with these recesses 21,
The stator 13 and the rotor 14 are integrated with the ball bearing 7 by fitting them into the ball bearings 22, respectively.

With this structure, as in the rotary transformer of the third embodiment, the centering work of the ball bearing 7, the stator 13 and the rotor 14 can be facilitated. Moreover, since the gap length is determined by the size of the ball bearing 7, the electrical characteristics of the rotary transformer alone can be fixed.

[0036]

As is apparent from the above description, in the rotary transformer of the present invention, since the stator and the rotor are integrated by the ball bearing, the gap length can be fixed by the rotary transformer alone.
The gap accuracy can be made stable. Further, since the gap can be determined as the rotary transformer alone, the electric characteristics can be improved by narrowing the gap. Further, the centering step of the rotary transformer is not necessary at the time of assembling the drum, and the assembling workability can be improved. Particularly, in the vertical rotary transformer, when the ball bearings are provided on the upper and lower sides, it is possible to prevent dust and the like from entering the gap portion and suppress the occurrence of hit noise.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotary transformer provided with a ball bearing on one side.

FIG. 2 is a sectional view of a rotary transformer in which ball bearings are provided above and below.

FIG. 3 is a sectional view of a rotary transformer in which ball bearings are fitted to a stator and a rotor.

FIG. 4 is a sectional view of a flat rotary transformer.

[Explanation of symbols]

 1 stator 2 rotor 3,4,17,18 coil arrangement groove 5,6,15,16 coil 7 ball bearing 8 ball 9 inner ring 10 outer ring 11,12,21,22 recess

Claims (4)

[Claims] 1. A rotary transformer in which a rotor and a stator are opposed to each other with a minute gap therebetween, wherein the rotor and the stator are integrated by a ball bearing. 2. The rotary transformer according to claim 1, wherein the ball bearings are provided above or below the rotary transformer or in any one of them. 3. The rotary transformer according to claim 1, wherein the rotor is fixed to an outer ring of the ball bearing, and the stator is fixed to an inner ring of the ball bearing. 4. The rotary transformer according to claim 1, wherein the ball bearing is fitted to the rotor and the stator.