JPS5811005Y2 - Shadow mask molding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a shadow mask forming apparatus used for forming slot-type shadow masks such as shadow masks for color cathode ray tubes.

FIG. 1 is a partial front view showing a flat mask with round holes.

In the structure, 1 is a flat mask, and 2 is an opening formed in the flat mask 1.

That is, as shown in Fig. 1, the shadow mask for color cathode ray tubes is made by annealing a flat mask 1 in which a large number of openings 2 for electron beam passage are formed in a cold-rolled steel plate to remove internal stress, and then subjecting it to a leveling process. This process removes annealing strain and prevents the defect of elongation at yield point during press forming, and is finally formed into a predetermined curved surface by press forming.

In such a pressing process, a press mold as shown in FIG. 2 is used.

FIG. 2 is a sectional view showing a conventional press mold.

In FIG. 1, corresponding parts are designated by corresponding reference numerals.

In the configuration, 3 is a wrinkle presser that presses the periphery of the flat mask 1, 3a is a convex portion provided around the wrinkle presser 3, and 4 is a wrinkle presser.
is a die for fixing the flat mask 1; 4a is a concave portion of the die 4 provided at a position opposite to the convex portion 3a of the wrinkle presser 3; 5 is a punch slidably disposed within the wrinkle presser 3;
6 is a pad arranged corresponding to the punch 5.

That is, the periphery of the flat mask 1 is firmly fixed by the convex part 3a of the wrinkle presser 3 and the concave part 4a of the die 4, and the punch 5 is
is slid inside the wrinkle presser 3 and pressed against the pad 6 to form the flat mask 1 into a spherical surface, and then the wrinkle presser 3 and die 4
A suitable interval of 0.3 to Q, 5 mm is left between the mask 1 and the mask 1, and the punch 5 and pad 6 are slid downward to bend the periphery of the flat mask 1 at right angles to form a mask skirt. .

Here, as shown in FIG. 1, the flat mask 1 in which round holes 2 are arranged regularly has almost uniform mechanical strength in all directions, so the flat mask 1 does not wrinkle during press forming. It conformed to the spherical surface of the convex portion 3a of the presser foot 3, and no problems occurred when the punch 5 was used to form the spherical surface.

However, a problem arises in the slot-type flat mask 1 as shown in FIG.

FIG. 3 is a partial front view showing a slot-type flat mask.

In the figure, parts corresponding to those in FIGS. 1 and 2 are designated by corresponding symbols.

In the configuration, 2a is a slot provided in the flat mask 1.

That is, the mechanical strength in the longitudinal direction and the transverse direction of the slot 2a has significantly different strength direction, and the slot-shaped flat mask 1 generally has a smaller opening area than the round-hole-shaped flat mask 1. Since it is very large, the overall strength is also significantly weakened.

Furthermore, the spherical surface of the slot-shaped shadow mask 1 generally has a larger curvature than the spherical surface of the round-hole-shaped shadow mask 1, and the drawing ratio during spherical molding is larger.

Slot-shaped flat mask 1 with these properties
When pressing, a concave bead is formed around the flat mask 1 by the convex portion 3a of the wrinkle presser 3, as shown in FIG.

FIG. 4 is a plan view showing a slot-type flat mask in which wrinkles have been suppressed using a conventional press die.

In the composition, 7 is a wrinkle. That is, in the spherical surface forming portion of the flat mask 1, fold-like wrinkles 7 are formed at or around the center of each side, and these fold-like wrinkles 7 are formed by the punch 5.
Even after the spherical surface is formed by the spherical surface forming method, the spherical surface is not completely stretched, and wrinkles 7 that locally protrude on the convex side of the spherical surface remain, making it difficult to perform the function of a shadow mask for a color cathode ray tube.

FIG. 5 is a partial sectional view showing details of a conventional press-type wrinkle presser.

FIG. 6 is a partial perspective view showing details of the shape of the flat mask when wrinkles are pressed by the press mold of FIG. 5. FIG.

That is, when pressing the slot-shaped flat mask 1, one of the causes of the crease-like wrinkles 7 is that the curvature of the slot-shaped flat mask 1 is larger than the curvature of the round-hole-shaped flat mask 1, as described above. Therefore, as shown in FIG. 5, the angle θ1 between the spherical part of the wrinkle presser 3 and the concave part 4a is smaller than that of the round hole type flat mask 1, and as shown in FIG. It was found that this was due to the fact that the curvature in the direction also increased, forcing the flat mask to be shaped beyond its deformability.

Furthermore, another cause of the crease-like wrinkles 7 is the dents in the spherical surface of the flat mask 1 and the dents in the beads formed around the flat mask 1. Since they are oriented in the same direction, the shadow mask No. 1, the drawing ratio during spherical molding becomes too large.

This invention was made in order to eliminate such drawbacks, and provides a shadow mask molding apparatus that can mold even a slot-type flat mask into a uniformly curved surface.

FIG. 7 is a partial sectional view showing details of the wrinkle presser in an embodiment of the shadow mask forming apparatus according to the invention.

In the configuration, 3b is a recess provided in the wrinkle presser 3;
is a convex portion provided on the die 4.

FIG. 8 is a partial perspective view showing details of the shape of the flat mask when wrinkles are pressed by the press mold of FIG. 7.

That is, one of the features of this invention is that the convex portion 4 of the die 4
The angle θ2 formed between the side wall of b and the surface of this die 4 is an obtuse angle.

Furthermore, another feature of this invention is that the flat mask 1
A recess 3b is formed in the wrinkle presser 3 so as to form a bead having a recess facing in the opposite direction to the spherical recess in the central part of the
The reason for this is that the die 4 is provided with a convex portion.

With the press die configured in this way, when forming beads at the edge of the flat mask 1, the mask 1 will not be bent beyond its deformability.

One reason for this is that the bending angle is an obtuse angle θ2 instead of an acute angle θ1 as in the conventional case.

Another reason is that the dents on the spherical surface at the center of the flat mask 1 and the dents on the bead are not oriented in the same direction, but are oriented in opposite directions.

That is, the curve forming the spherical surface of the flat mask 1,
This is because the change in curvature at the boundary with the curve forming the recess of the bead can be reduced, so that the curves form a smooth extension of each other.

This becomes clear when comparing FIG. 5, which shows a conventional example, and FIG. 7, which shows an embodiment of this invention.

That is, by orienting the dents of the spherical surface and the dents of the bead in opposite directions, the drawing ratio when forming the spherical surface of the flat mask 1 can be reduced.

Therefore, as shown in FIG. 8, even a slotted flat mask 1 having a large curvature in the peripheral direction can be formed into a uniform curved surface without producing creases 7 during pressing.

Furthermore, this invention has the effect that even a slot-type flat mask can be formed into a uniform curved surface with a very simple structure.

[Brief explanation of the drawing]

FIG. 1 is a partial front view showing a flat mask with round holes. FIG. 2 is a sectional view showing a conventional press die. FIG. 3 is a partial front view showing a slot-type flat mask. FIG. 4 is a plan view showing a state in which a slot-type Furazo I mask is pressed with wrinkles using a conventional press die. FIG. 5 is a partial sectional view showing details of a conventional press-type wrinkle presser. FIG. 6 is a partial perspective view showing details of the shape of the flat mask when wrinkles are pressed by the press mold of FIG. 5. FIG. FIG. 7 is a partial sectional view showing details of the wrinkle presser in an embodiment of the shadow mask forming apparatus according to the invention. FIG. 8 is a partial perspective view showing the details of the shape of the flat mask when wrinkles are pressed by the press die of FIG. 7. Note that corresponding parts in the drawings are designated by corresponding reference numerals. In the figure, 1 is a flat mask, 3 is a wrinkle presser, 3b
4 is a concave portion, 4 is a die, and 4b is a convex portion.

Claims (1)

[Scope of claim for utility model registration] The invention is for spherical molding of shadow mask material,
and a shadow mask forming apparatus including first and second molds for forming a bead in the shadow mask material having a recess facing in a direction opposite to a spherical recess, the first mold forming a bead. The second mold has a protrusion for forming, and the second mold has a recess corresponding to the protrusion.
Thereby, the recesses of the bead are formed to face in the opposite direction to the recesses of the spherical surface of the shadow mask, and further, the bending angle between the flat part of the shadow mask and the bead part is an obtuse angle. 1. A shadow mask molding device, characterized in that the protruding portion and the recessed portion are formed in the shadow mask forming apparatus.