JP2566532Y2 - Core for deflection yoke - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke core used in various CRT (cathode ray tube) displays such as a television receiver. More specifically, by imparting a round shape to at least the outer peripheral edge portion of the bottom surface of the concave portion provided on the end face of the ring-shaped core, the powder flowability during molding is improved, and the molding pressure is made uniform, The present invention relates to a deflection yoke core that prevents swelling at the bottom of a concave portion after firing.

[0002]

2. Description of the Related Art There are various types of deflection yoke cores. Basically, the deflection yoke core has a ring shape having a flared portion so as to surround the outer periphery of a neck portion of a CRT. Usually, in order to facilitate mounting of the coils on the core, the structure is such that it can be divided into two symmetrically with respect to the center axis. This division is performed by forming V-shaped division grooves at predetermined positions on the outer peripheral surface and the inner peripheral surface of the portion of the ring-shaped core that spreads in a trumpet shape, and applying a mechanical or thermal shock to the core. Then, after applying a coil winding to a half-ring-shaped core obtained by dividing into two, the divided surfaces are aligned so as to have the original ring shape, and united with a fastener, etc.
Attach to RT neck.

FIG. 4 and FIG. 5 are enlarged views of a portion of the half ring-shaped core according to the prior art on the small diameter side as viewed from the direction of the division surface. In both figures, A indicates the state at the time of molding, and B indicates the state after firing. A concave portion 16 having a flat portion parallel to the end surface 12 of the semi-ring core 10 is formed in the vicinity of the dividing surface 14 of the large-diameter side end surface and the small-diameter side end surface 12 of the semi-ring core 10. in this case,
The recess 16 serves as a chucking groove for positioning the winding machine.
The bottom surface of the concave portion 16 has a flat portion 18 as shown in FIG. 4 and an inclined surface 20 on the outer peripheral side of the flat portion 18 as shown in FIG. There are cases. In any case, recess 1
Chucking to the winding machine is performed using the flat portion 18 of FIG.

[0004]

As is well known, such a deflection yoke core is prepared by filling a ferrite magnetic powder containing a binder in a mold having a predetermined shape, press-molding with a press machine, It is manufactured by firing. As shown in FIG. 4A, when pressure molding is performed using a mold in which the entire bottom surface of the concave portion 16 becomes a flat surface, the flow of the powder is hindered at the ridge line portion (indicated by a) of the concave bottom surface. As shown by arrows, pressure concentrates on the ridge. Therefore, after the firing, a bulge 22 occurs due to concentration of pressure on the bottom surface of the concave portion 16 as shown in FIG. Further, as shown in FIG. 5A, the outer peripheral side of the bottom surface of the concave portion 16 is further lowered and the inclined surface 2 is formed.
Even when the pressure is set to 0, if pressure molding is performed using a mold having such a shape, the ridge portion on the bottom surface of the concave portion (indicated by reference numerals a and b).
As a result, the flow of the powder is hindered, and the pressure concentrates on the ridge portion as shown by the arrow. As a result, swelling 22 occurs due to concentration of pressure after firing as shown in FIG.

For example, when a concave portion is used as a chucking groove for a winding machine, chucking is performed from the outer peripheral side of the core and pressed and held at a flat portion on the bottom surface of the concave portion. If there is, it will not be possible to chuck correctly. Then the winding state (winding start position,
Winding pitch, winding angle, etc.) are not performed as predetermined, and the desired performance as a deflection yoke cannot be obtained. A similar problem arises when the concave portion is used as a positioning groove when a synthetic resin separator (coil winding frame) is mounted. Further, when the core is chucked, the load concentrates on the bulging portion, so that the core is likely to be broken. Furthermore, since the pressure is concentrated on a specific portion (ridge portion on the bottom surface of the concave portion) at the time of press molding, there is a disadvantage that abrasion of the mold is quick and manufacturing cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to prevent the occurrence of bulging at the bottom of the concave portion, to enable the concave portion to be used for accurate chucking and positioning, and to reduce core defects. It is an object of the present invention to provide a deflection yoke core which can prevent the occurrence of the die and further reduce the wear of the mold.

[0007]

SUMMARY OF THE INVENTION The present invention is a deflection yoke core in which a concave portion is provided on the large-diameter side and / or the small-diameter side end surface of a ring-shaped core having a flared portion. In order to achieve the above object, in the present invention, the bottom shape of the concave portion, while leaving a flat portion parallel to the end face of the ring-shaped core, at least the entire outer peripheral edge of the bottom surface is rounded, There is a feature in the point.

[0008] Here, it is preferable that the portion to be rounded is not only the outer peripheral edge of the bottom surface of the concave portion but also both the outer peripheral edge and the inner peripheral edge. This concave portion is used as a groove for positioning when a synthetic resin separator serving as a coil winding frame is mounted, in addition to chucking to a winding machine.

[0009]

When the entire edge of the bottom surface of the concave portion has a round shape, the fluidity of the powder at the time of molding becomes good, and the molding pressure becomes uniform. Therefore, abrasion of the mold is reduced, and at the same time, swelling does not occur during firing. In addition, since a flat portion without swelling remains on the bottom surface of the concave portion, chucking of the core and positioning of the synthetic resin separator can be accurately performed by using this portion.

[0010]

FIG. 1 is a perspective view showing an embodiment of the present invention, showing a half-ring core 30 divided into two parts. The deflection yoke core has concave portions 36 on both the large-diameter end surface 32 and the small-diameter end surface 34 of the ring-shaped core having a flared portion. In this embodiment, since the concave portion 36 is used as a chucking groove for positioning the winding machine, the concave portion 36 is formed at both end portions of the division surface 38. Reference numeral 39 denotes a mounting groove of a fastening fitting when the two half-ring-shaped cores are united.

In this embodiment, the concave portion 36 has a round shape 42 on both the outer peripheral edge and the inner peripheral edge of the bottom surface while leaving the flat portion 40 parallel to the core end surface 34.
Here, the size of the round shape 42 needs to be at least 1 mm or more in radius at the time of molding. Conversely, if the size is large, it is at most 1/3 or less of the width of the concave portion. If it is larger than that, chucking workability is undesirably reduced.

FIG. 2 shows a state near the concave portion on the small diameter side during molding, and FIG. 3 shows a state near the concave portion on the large diameter side. At the time of molding, the fluidity of the powder is improved by the round shape 42 as indicated by the arrow, and the molding pressure is also made uniform. Therefore, the mold is less likely to be worn, and the swelling does not occur after firing as in the prior art.

Although the above embodiments are all directed to the concave portion for chucking the deflection yoke core on the winding machine, the present invention can be applied to other concave portions (grooves). For example, in the deflection yoke core, the large diameter side and / or
Alternatively, a synthetic resin separator (coil frame) for winding may be attached to the end surface on the small diameter side. Usually, a concave portion for positioning is provided on the core end face, and the protrusion of the synthetic resin separator is fitted. This concave portion is provided at a position other than the chucking groove (a position distant from the division surface). Also in this case, if there is a bulge in the flat portion of the bottom surface of the concave portion, the positioning cannot be performed accurately and the winding cannot be accurately positioned. Therefore, by applying the present invention to the positioning concave portion fitted to the projection of the synthetic resin separator, the inconvenience caused by the bulging can be solved.

[0014]

According to the present invention, as described above, the entire bottom edge of the concave portion is rounded, so that the powder fluidity during molding is improved, and the molding pressure is not locally increased. ,
It is possible to prevent swelling from occurring on the bottom surface of the concave portion. In addition, since there is a flat portion without swelling parallel to the core end surface on the bottom surface of the concave portion, accurate and reliable chucking can be performed, for example, when used for chucking a winding machine. Performance can be obtained. In addition, since there is no unnecessary swelling, a locally high chucking pressure is not applied at the time of core chucking, and there is no possibility of core loss. Even when a synthetic resin separator serving as a coil winding frame is mounted, accurate positioning can be performed similarly.

Further, since pressure is not locally applied during molding as described above, abrasion of the metal mold can be reduced, and there is no possibility that the production cost will be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a semi-ring shaped core according to the present invention.

FIG. 2 is an explanatory view of the vicinity of a concave portion on a small diameter side of a core during molding.

FIG. 3 is an explanatory view of the vicinity of a concave portion on a large diameter side of a core during molding.

FIG. 4 is a perspective view showing an example of a conventional technique.

FIG. 5 is a perspective view showing another example of the prior art.

[Explanation of symbols]

 Reference Signs List 30 Semi-ring core 32 Large-diameter end face 34 Small-diameter end face 36 Concave part 38 Dividing surface 40 Flat part 42 Round shape

Claims (2)

(57) [Scope of request for utility model registration] 1. A deflection yoke core in which a concave portion is provided on an end face on a large diameter side and / or a small diameter side of a ring-shaped core having a portion extending in a trumpet shape, a bottom surface of the concave portion is formed on an end face of the ring-shaped core. A deflection yoke core, wherein at least the entire outer edge of the bottom surface is rounded while leaving parallel flat portions. 2. The deflection yoke core according to claim 1, wherein both the outer peripheral edge and the inner peripheral edge of the bottom surface of the concave portion are entirely rounded.