JPS60184428A - Press forming method - Google Patents

Abstract

PURPOSE:To form a base material by a press without deforming a minute porous part of the base material by forming a bead part and an outside periphery bend part by a projecting part, in a state that a plate base material is formed to a curved surface and inserted and held by a curved surface forming punch and a pad. CONSTITUTION:When forming by a press a plate-shaped shadow mask 1b having a minute porous part in the center part, to a shadow mask formed part having a band-shaped bend part vertical to a bead part on a curved surface-shaped plate and its outside peripheral part, a press die formed by providing a curved surface forming punch 9, a pad 11 placed so as to correspond to said punch, and a bead part forming projecting part 12 is used, a punch is made to descend, and the punch 9 is made to descend in a state that said plate-shaped base material 1b placed on the pad 11 is inserted and held between a wrinkle holder 8 and a die 10. In this way, the base material 1b is formed to a curbed surface by the punch 9 and the pad 11 and also inserted and held, the punch 9 and the pad 11 are further made to ascend in said state, the bead part is formed by the projecting part 12 on the outside peripheral part of the curved surface part, and the bend part is formed by the die 10, by which the formed part 1a is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a press-molding method for a curved plate having minute pores and the bent portion, such as a Jado Manuk used in a color picture tube. It is something.

2. Construction of a conventional example and its problems As a conventional example, there is a shadow mask 1+! used in a color picture tube shown in FIG. Press molding of L will be explained. Conventionally, in such press molding, a press die as shown in FIG. 2 has been used. In Figure 2, 1
b is a flat shadow mask shown in FIG. 3; 3 is a wrinkle presser to prevent wrinkles from forming around the shadow mask when pressing the periphery of the shadow mask 1b to form a curved surface;
4 is a punch which is slidably disposed within the wrinkle presser 2 and which extends the flat shadow mask into a curved shape; 6;
A die for forming the periphery of the flat shadow mask corresponds to the wrinkle presser 3, a pad 6 is disposed corresponding to the punch 4, and a pad 7 is provided on the outer peripheral surface of the shadow mask to reinforce the shadow mask. The pad is integrally constructed with the pad, and is a protrusion for forming a bead portion having a concave shape facing in the opposite direction to the curved convex molding.

When performing press molding in the above configuration, since the curved surface forming pad of the lower mold and the bead section are integrated, the bead section is formed slightly faster than the curved surface forming section.

In this case, since the outer periphery of the shadow mask is fixed by the ridges, the shadow mask is pulled in the outer periphery direction during curved surface forming, and the electron beams pass through the many holes made on the shadow mask surface as shown in FIG. This had the disadvantage that the minute slot hole 2a was deformed as shown in 2b shown in FIG.

Purpose of the Invention The present invention solves the problem of shape irregularities such as deformation of micropores in press molding of a curved plate having minute pores with a band-shaped bent portion almost perpendicular to the curved plate at its outer periphery. If this is something that can be resolved, we will try to stabilize the quality.

Composition of the Invention The press molding method of the present invention includes a pad for stretching a flat plate onto a curved plate, and a curved pattern opposite to that formed near the outer periphery of the curved plate in order to reinforce the curved plate. By separating the protruding part for forming the bead part, which has a concave shape facing in the direction, and arranging the overhanging pad closer to the punch side than the protruding part, the flat plate is first formed into a curved surface during press forming. After the bead is formed and clamped, the protrusions and outer circumferential bending portion for forming the bead are drawn, so that the curved surface portion is not constrained by the forming of the protrusions and the outer circumferential bending portion, and It is possible to eliminate shape irregularities caused by deformation of a large number of micropores on a curved plate, which is extremely advantageous in terms of quality stability.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 6 to 10.

In FIG. 6, reference numeral 8 denotes a wrinkle presser that prevents wrinkles from forming around the shadow mask 1b, and 9 is a wrinkle presser that is slidable within the wrinkle presser 8 and is used to stretch the flat shadow mask into a curved shape. A punch, 10 is a die for fixing the periphery of the flat shadow mask in correspondence with the wrinkle presser, 11 is a pad arranged corresponding to the punch 9, and 12 is a protrusion for forming a bead portion. The pad 11 is located at a position farther from the punch (h is 0 or more). 13 is an upper mold holder from which the punch 9 is suspended. 14 is a spring that presses down the wrinkle presser 8. 15 is a lower mold holder.

When performing press molding with the above configuration, the upper mold holder 13 is lowered as shown in FIG.
When the shadow mask 1b is lowered, the overhanging pad 11 is closer to the punch side than the protrusion 12, as shown in FIG. .

Furthermore, the upper die holder 13 descends, and the punch 9 and pad 1
1 and 1, the shadow mask 1b hits the protrusion 12 for forming the bead portion, and as shown in FIG. 9, the forming of the bead portion begins.

Further, the upper mold holder 13 is lowered and the side surface of the die 10 and the side surface of the punch 9 begin to form the outer circumferential bent portion of the shadow mask 1b, as shown in FIG. When the upper mold holder 13 further descends, the lower surface of the pad 11 stops touching the upper surface of the lower mold holder 16, and at the same time, the molding of the shadow mask 1b is completed, resulting in the molded product 1a shown in FIG.

Effects of the Invention According to the press molding method of the present invention, the bead portion and the outer circumference bending portion are formed while the curved surface portion of the molded product is being formed and clamped. I won't accept the part. Therefore, there is no deformation of the large number of slot holes drilled on the shadow mask surface due to one-shot molding, and a shadow mask having slot holes of uniform size can be molded.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a shadow mask molded product used in color picture tubes, Figure 2 is a sectional view of a conventional mold, Figure 3 is a perspective view of a flat plate of a shadow mask, and Figure 4 is a perspective view of a shadow mask flat plate. FIG. 5 is an enlarged perspective view of a slit hole for electron beam passage drilled on a curved surface of a molded product, and FIG. 6 is an enlarged perspective view of a slit hole for electron beam passage drilled in The cross-sectional view of the mold and FIGS. 7 to 10 are diagrams of the shadow mask molding process in the same mold. 8...Wrinkle presser, 9...Curved surface forming punch, 10...Die, 11...Pad,
12...Protrusion portion for forming bead portion, 13...
...Upper mold holder, 14... Spring, 16...
...Lower mold holder. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
V;4 Figure 4a Figure 5b

Claims (1)

[Claims] A flat plate with minute pores on the entire surface or in the center is formed into a curved plate, the outer periphery of the flat plate is bent into a band-like shape almost perpendicular to the flat plate, and a curved convex molding is formed near the outer periphery of the curved plate. When molding a bead portion having a concave shape facing in the opposite direction, the pad arranged corresponding to the curved punch and the protrusion portion for molding the bead portion are separated, and the pad and the punch are used to form a flat plate. A press forming method characterized by clamping the material and then forming a bead part and a circumferentially bent part.