JPH0328520Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a core for a deflection yoke of a cathode ray tube used in television receivers and the like.

[Prior art and its problems]

A deflection yoke is attached to the neck of the cathode ray tube in a television receiver. The deflection yoke basically consists of two sets of horizontal and vertical deflection coils, which are assembled at right angles to each other, and a core for the deflection yoke. This core for the deflection yoke is formed by combining a pair of semicircular halves with a fastening fitting to form an annular shape, and the core is shaped like a lug as a whole. The core for the deflection yoke is made by powder pressure molding of a rubber-shaped piece with a dividing groove and metal fastening grooves on both sides of the core in order to facilitate the installation of the coil, and after firing, the core is molded using the dividing groove. , divide it into two parts,
A deflection coil is attached to each of the divided halves, and finally they are tightened together using metal fittings placed in the tightening grooves.

5 to 7 show typical examples of cores for deflection yokes that have been generally used in the past. ' is a dividing groove aligned with the groove 2 on the inner circumferential surface of the core, and is formed in a substantially rectangular shape on both sides, and gradually becomes shallower and opens toward the narrow opening side 4.

A core for a deflection yoke having such a metal fastening groove 3 is molded in the attitude shown in FIG. 5 by powder pressure molding. However, at that time, the powder magnetic material is swept away in the direction of the narrow opening at the ridge 5 on the narrow opening side 4 of the metal fastening groove 3. For this reason, the pressurization density at that portion is reduced, resulting in the disadvantage that cracks or chips occur in the edge portion 5.
In other words, the bottom part of the metal fastening groove has a high density of compressed powder because the lower mold protrudes, but the part in contact with both side walls, especially the outer part, becomes locally coarse due to the flow of the powder. This may cause cracks.
The area in contact with the inner wall is also a little rough, but the tightening grooves and split grooves considerably suppress the flow of powder, so there is no problem.

[Purpose of invention]

The present invention aims to prevent the above-mentioned problem in the core for a deflection yoke, that is, the occurrence of cracks or chips in the core caused by the shape of the metal fastening grooves formed on both sides of the dividing groove.

[Summary of the structure and effects of the invention]

The present invention is a deflection yoke core in which a pair of semicircular halves are fastened together with a fastening metal fitting to form a lug shape. It is characterized in that the ridge corner in the direction of the narrow opening of the groove is curved outward. Preferably, the edge portion is formed into an arc shape.

According to the configuration of the present invention, the flow of the powder magnetic material is forced to the outside of the fitting fastening groove during powder pressure molding. Therefore, the density of the core in the part of the metal fitting tightening groove becomes almost uniform, and cracks and chips are prevented.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4. In these figures, elements similar to those shown in Figures 5-7 are designated by the same reference symbols.

The core 1 for the deflection yoke is a truss-shaped core having a narrow opening 6 and an enlarged opening 7, and extends to the outer and inner peripheral surfaces of the core along a plane including the axis of the core 1 and one diameter. It can be divided into halves by dividing grooves 2, 2'. core 1
Metal fastening grooves 3, 3 are formed on both sides of the dividing groove 2 on the outer circumferential surface of the divider for fixing the deflection coils together after winding them around the divided halves.
Although the above structure is the same as that of the conventional core for a deflection yoke, the present invention is unique in the structure of the metal fastening grooves 3, 3.

The metal fitting tightening groove 3 (four metal fitting tightening grooves are shown in the figure, but since they are the same or mirror images, only one will be explained) is a substantially rectangular shape extending in the direction along the axis of the core 1. The inner wall of the groove (on the side of the dividing groove 2) is formed approximately perpendicular to the groove bottom so as to be able to hold the fastener, while the outer wall is slightly tapered. Further, the narrow opening 6 side of the groove 3 is open. The ridge 8 on the narrow opening side of the metal fastening groove 3 is curved outward in accordance with the present invention.

FIG. 4 shows details of the metal fitting tightening groove 3. A ridge 8 on the narrow opening side of the groove 3 is a surface that curves outward from near a line 9 where the bottom of the groove 3 begins to become shallow. This curved surface may be a smooth curved surface or an arc shape, or may be several bent planes. To give an example, when the wall thickness of the core 1 is approximately 5 mm and the width t ₁ of the outer wall of the groove 3 in FIG. There was no effect when ₂ was set to about 1.5 mm, but excellent effects were obtained when it was set to 2.5 mm or more, especially 3.0 mm or more. Note that the ridge portion 8 can be easily designed based on experiments.

[Function and effect of the idea]

With the above configuration, in the posture shown in Figure 1, powder magnetic material (especially ferrite) is placed in the mold.
When the powder material is charged and pressure-molded, the powder material is forced to the outside of the fitting fastening groove 3 by the mold surface corresponding to the ridge 8. For this reason, the entire metal fitting tightening groove has a nearly uniform pressure density,
A core for a deflection yoke is provided in which the occurrence of cracks or chips due to non-uniformity of pressurization density, which has been considered a drawback in the past, has been eliminated.

[Brief explanation of drawings]

Fig. 1 is a front view showing a part of the deflection yoke core of the present invention in cross section, Fig. 2 is a bottom view of the same, Fig. 3 is a plan view of the same, Fig. 4 is an enlarged view of the main parts, and Fig. 5 The figure is a front view showing a part of a conventional deflection yoke core in cross section, FIG. 6 is a bottom view thereof, and FIG. 7 is a plan view thereof. The main parts in the figure are as follows. 1: Core for deflection yoke, 2, 2': Groove for division,
3: Groove for tightening metal fittings, 4: Narrow opening side of the groove, 6:
Narrow opening, 7: Enlarged opening, 8: Edge corner.

Claims (1)

[Scope of utility model registration request] A core for a deflection yoke having a narrow opening and an enlarged opening, the core having a pair of semi-annular half portions on the circumferential surface of the core along a line of intersection with a plane including the axis of the core. the core has a substantially rectangular metal fastening groove extending parallel to the dividing groove on the outer peripheral surface of the core on both sides of the dividing groove; released on the narrow opening side, a side surface of the tightening groove on the dividing groove side is formed substantially parallel to the plane, and a ridge corner portion of the side surface of the tightening groove on the side far from the dividing groove in the direction of the narrow opening. A core for a deflection yoke, characterized in that the core is curved in a direction away from the dividing groove.