JPH08264134A - Deflecting yoke - Google Patents

Abstract

PURPOSE: To lower the vibration of magnetic pieces and at the same time insulate sound in order to lower the beating sound by covering the magnetic pieces which are to be attached to an insulating frame with a prescribed visco-elastic body. CONSTITUTION: A deflecting yoke 1 is provided with a horizontally deflecting yoke coil 2, a vertically deflecting yoke coil 4 coiled on a circular core, an insulating frame 5 which is made of resin and composes a coil separator to insulate those coils 2, 4, and magnetic pieces 6 attached to the frame 5. The outer circumference sides of the magnetic pieces 6 are covered with visco-elastic unvulcanized butyl rubber 7 and the vibration of the magnetic pieces 6 which alter alternately the vertically deflecting magnetic field is absorbed in the rubber 7. Consequently, the vibration of the magnetic pieces 6 can be lowered and at the same time sound is insulated, so that beating sound can be lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke used in a television receiver or the like.

[0002]

2. Description of the Related Art In recent years, in television receivers, image distortion (particularly pincushion distortion) has increased due to higher inch and flat faced CRTs. There is.

A conventional deflection yoke will be described below.

FIG. 7 is a side view of a conventional deflection yoke, FIG. 8 is a sectional view taken along the section line AA of FIG. 7, and FIG. 9 is a section line BB of FIG. It is sectional drawing of the upper side along a line.

In these figures, 2 is a horizontal deflection coil, 4 is a vertical deflection coil wound around an annular core 3, and 5 is a vertical deflection coil.
Is a pair of insulating frames (coil separators) made of resin that insulates the horizontal deflection coil 2 and the vertical deflection coil 4, and 6 is a magnetic piece mounted on the insulating frame 5.

Next, the function of the magnetic piece 6 will be described.

FIG. 10 shows lines of magnetic force generated from the vertical deflection coil 4 in a state where the magnetic piece 6 is not attached, and FIG.
Shows the magnetic field lines generated from the vertical deflection coil 4 with the magnetic piece 6 attached, and FIG. 12 is a diagram showing the magnetic field strength of the vertical deflection magnetic field in the CRT tube axis direction. 12, the solid line shows the state where the magnetic piece 6 is not attached, and the broken line shows the state where the magnetic piece 6 is attached.

As can be seen from FIGS. 10 and 11, the magnetic piece 6 has a function of partially absorbing the vertical deflection magnetic field, and weakens the magnetic field on the electron gun side as shown in FIG.
The pincushion distortion on the tube surface is improved by making the magnetic field on the tube surface side relatively strong.

That is, when the magnetic piece 6 is not attached, the image distortion shown by the solid line in FIG. 13 can be improved by attaching the magnetic piece 6 as shown by the broken line in FIG. .

[0010]

However [0007] In the conventional deflection yoke 1 _0, a vertical deflection magnetic field, for changing AC-according vertical synchronizing frequency, magnetic as indicated by arrow marks in FIG. 14 There is a problem in that the piece 6 vibrates and a whine is generated.

In order to solve such a problem, for example, Japanese Utility Model Laid-Open No. 63-33552 proposes to embed a magnetic piece in an insulating frame in advance and mold the magnetic piece. The molding of the embedded insulating frame requires a special mold, and the molding is not easy, which is not suitable for mass production.

The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a deflection yoke which can reduce the beat noise due to the magnetic pieces and can be easily mass-produced.

[0013]

In order to achieve the above-mentioned object, the present invention is constructed as follows.

That is, according to the present invention, in a deflection yoke comprising an insulating frame for insulating the horizontal deflection coil and the vertical deflection coil and a magnetic piece mounted on the insulating frame, the magnetic piece is a viscoelastic body. It is characterized by being covered.

As the viscoelastic body, for example, unvulcanized rubber can be used.

[0016]

According to the present invention having the above structure, the magnetic piece is
Since it is covered with a viscoelastic body, the vibration of the magnetic piece can be absorbed by the viscoelastic body and the vibration can be reduced. You can also

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a deflection yoke according to an embodiment of the present invention, and the portions corresponding to those of the conventional example of FIG. 8 are designated by the same reference numerals.

The deflection yoke 1 of this embodiment includes a horizontal deflection coil 2 and a vertical deflection coil 4 wound around an annular core 3.
And a pair of resin-made insulating frames (coil separators) 5 that insulate the coils 2 and 4 from each other, and a magnetic piece 6 attached to the insulating frame 5. It is similar to the conventional example, and its side view is also similar to the conventional example of FIG.

In this embodiment, in order to reduce the vibration of the magnetic piece 6 caused by the change of the vertical deflection magnetic field in the alternating current to reduce the beat noise, the following structure is adopted.

That is, in the deflection yoke 1 of this embodiment, the outer peripheral sides of the magnetic pieces 6 mounted on the pair of insulating frames 5 are covered with unvulcanized butyl rubber 7 which is a viscoelastic body, so that the magnetic pieces 6 are covered. I try to absorb the vibration.

The basic concept of vibration absorption of the magnetic piece 6 by the viscoelastic body will be described below.

First, as shown in the schematic view of FIG. 2, when a substance provided for absorbing the vibration of the magnetic piece 6 is represented as a spring having an elastic modulus G, the relationship between the stress F of the spring and the displacement ε is: It is shown by the following formula.

F = Gε (1) Further, as shown in the schematic diagram of FIG. 3, a substance provided for absorbing the vibration of the magnetic piece 6 is viscoelastic having both the elastic modulus G and the viscosity μ. Expressed as a body, the spring stress F and displacement ε
The relationship between and is shown by the following equation.

DF / dt =-(G / μ) F + G (dε / dt) (2) Here, G / μ is generally referred to as relaxation time and represents a delay time of deformation.

In an elastic body such as vulcanized rubber or resin,
As shown in the equation (1), the vibration energy is temporarily stored in the inside, but it is released at the next moment, and as a result, the vibration cannot be absorbed.

On the other hand, a viscoelastic body such as unvulcanized rubber having both elasticity and viscosity can absorb vibrations due to the time lag between the displacement of the spring and the displacement of the viscous flow.

Furthermore, as shown in FIG. 4, the beat noise is generated by the vibration of the magnetic piece 6 being propagated through the air, and therefore, as shown in FIG. When covered with the vulcanized butyl rubber 7, vibrations are less likely to be transmitted to the air and a soundproof effect can be achieved.

As described above, by covering the magnetic piece 6 with the unvulcanized butyl rubber 7, it is possible to absorb the vibration of the magnetic piece 6 and to prevent noise. It can be reduced.

Moreover, mass production is easier than the conventional example in which the magnetic piece 6 is embedded in the insulating frame 7 and molded.

FIG. 6 is a sectional view of the vicinity of a magnetic piece according to another embodiment of the present invention.

In this embodiment, a rib 8 for mounting the magnetic piece 6 is provided on the outer periphery of the insulating frame 5, the magnetic piece 6 is attached to the rib 8, and both surfaces of the magnetic piece 6 are, for example, unvulcanized butyl rubber 7 It is covered with a viscoelastic body such as, and thereby, the vibration absorbing effect and the soundproofing effect can be further enhanced, and the humming noise can be further reduced.

Although unvulcanized butyl rubber is used as the viscoelastic body in the above-mentioned embodiments, other unvulcanized rubber such as natural rubber, SBR, BR, nitrile rubber, and silicone rubber may be used. Good.

[0034]

As described above, according to the present invention, since the magnetic piece mounted on the insulating frame is covered with the viscoelastic body such as unvulcanized rubber, the vibration of the magnetic piece is prevented by the viscoelastic body. The vibration can be absorbed to reduce the vibration, and the sound can be prevented, so that the generation of the humming noise can be reduced.

Moreover, mass production is easier than the conventional example in which the magnetic piece is embedded and molded in the insulating frame.

[Brief description of drawings]

FIG. 1 is a sectional view of a deflection yoke according to an embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining vibration absorption by an elastic body.

FIG. 3 is a schematic diagram for explaining vibration absorption by a viscoelastic body.

FIG. 4 is a diagram for explaining the spread of a beat sound.

FIG. 5 is a diagram for explaining a soundproof effect.

FIG. 6 is a sectional view of an essential part of another embodiment of the present invention.

FIG. 7 is a side view of a deflection yoke.

8 is a cross-sectional view taken along the section line AA of FIG.

9 is a cross-sectional view of the upper side taken along section line BB of FIG.

FIG. 10 is a diagram showing a vertical deflection magnetic field without a magnetic piece attached.

FIG. 11 is a diagram showing a vertical deflection magnetic field with a magnetic piece attached.

FIG. 12 is a diagram showing the strength of a vertical deflection magnetic field depending on the presence or absence of a magnetic piece.

FIG. 13 is a diagram showing image distortion depending on the presence or absence of a magnetic piece.

FIG. 14 is a diagram showing vibration of a magnetic piece.

[Explanation of symbols]

1,1 ₀ Deflection yoke 2 Horizontal deflection coil 3 Core 4 Vertical deflection coil 5 Insulation frame 6 Magnetic piece 7 Unvulcanized butyl rubber (Viscoelastic body)

Claims (2)

[Claims] 1. A deflection yoke comprising an insulating frame for insulating a horizontal deflection coil from a vertical deflection coil, and a magnetic piece mounted on the insulating frame, wherein the magnetic piece is covered with a viscoelastic body. Characteristic deflection yoke. 2. The deflection yoke according to claim 1, wherein the viscoelastic body is unvulcanized rubber.