JPS61176429A - Shadow mask forming die - Google Patents

Abstract

PURPOSE:To relax the holding of a shadow mask and to prevent the deformation of an electron beam passing hole, by changing the clearance between a blank holder and a die in a shadow mask forming stage. CONSTITUTION:A shadow mask forming die is constituted of a blank holder 18 made to prevent creases from generating in the circumference of a shadow mask, a punch 19 arranged freely slidably in the holder 18 and used for bulging a flat shadow mask into a curved surface, a die 22 for forming the shadow mask in correspondence with the holder 18, a pad 23 for holding and floating the die 22 and taking out a formed shadow mask 1, upper and lower stoppers 24, 25 for floating the holder 18 and maintaining the clearance between the holder 18 and the die 22 on the way of forming, and a die set 26 for fixing the lower stopper 25.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a mold for forming a shadow mask in a cathode ray tube of a color television.

BACKGROUND OF THE INVENTION In recent years, as color televisions have become more vivid, the pitch of electron beam passage holes in shadow masks has become smaller, and the electron beam passage holes tend to become more easily deformed during shadow mask forming, as shown in Figure 11. I will explain an example of a conventional molding die, a conventional example patent, Japanese Patent Publication No. 54-273.
59 Figures 2 and 13 are cross sections of conventional molding molds.
is fixed to the lower die set 9 by a die, and the 4 punches are fixed to the upper die set 8, and a plaque holder 6 is suspended from the outer circumference by a hanging bolt 12, and the upper surface of the punch is held down by a spring 7. A pad 6 faces the die 3 and slides into the die 3 so that it can move freely.The bottom surface of the pad 6 is pressed by a cushion rod 14.1o adjusts the position of the upper die center and the lower die set. 11 is the opponent's post. 13 is the positioning pin of the flat mask.

Explanation of the operation When the flat shadow mask 1 is placed on the die 4, aligned with the positioning bin 13, and the upper die set 8 is lowered, the blank holder 6 is placed on top of the flat shadow mask 1, as shown in Fig. 14. When the upper die set 8 further descends, the punch 4 hits the flat glossy mask and is overcome by the pushing force of the pad 7, reaching the bottom dead center as shown in FIG. 15.

Next, when the upper mold holder 8 rises, the blank holder 5 separates from the die 3, and the distance therebetween becomes greater than the height of the edge of the molded product 2, as shown in FIG. 16.

When the upper die set 8 further rises, the cushion rod 1
4, the pad 6 is pushed up and the molded product is pushed up from inside the die, as shown in Fig. 17. However, the electron beam passage holes in the flat plate shadow mask 1 are long and have many holes shaped as shown in Fig. 11. Therefore, it has a property that it tends to expand during molding as shown in FIG. 12.Therefore, there is a problem in that the elongated hole tends to expand when it is pressed by the blank holder 5 and die 3 during the molding process.

Also, the positions of the die 3 and the blank holder 6 are regulated by the outer post 1Q and the bush 11, but the positions of the blank holder 5 and the die 3 are adjusted because there is no guide part. has the problem that it is unstable and the contact surface changes every time it descends, making it unstable for mass production.

Problems to be Solved by the Invention In view of the above-mentioned problems, the present invention aims to prevent the expansion of the hole through which the electron beam passes when molding the shadow mask.In order to prevent the hole through which the electron beam passes when molding the shadow mask, the gap between the flat shadow mask and the blank holder is closed during the molding process. To provide a mold structure that makes it easy to change the shape of the flat shadow mask, and to adjust the position of the blank holder and die so that even if the upper die set is slightly tilted, the position is stable and the contact between the blank holder and the die does not change. The purpose is to obtain (type structure).

Means for Solving the Problems In order to solve the above-mentioned problems, the shadow mask mold of the present invention has a stopper located under the blank holder when the upper die set is lowered and a curved surface is formed to stop the die and the blank holder. This method allows forming by creating a gap between the two and reducing the deformation of the electron beam passage hole in the flat shadow mask. In addition, in order to stabilize the position of the blank holder and die, a guide post is fixed to the die, and a sliding hole is provided to guide the blank holder/lower die set that faces this guide post to maintain the positional accuracy of the blank holder and die. It is.

According to the present invention, when a flat shadow mask is molded into a curved surface with the above-described configuration, the blank holder hits the stopper, creating a gap between the die and the blank holder, and the pressure on the shadow mask is relaxed, so that the electron beam passage hole can be expanded during molding. 9 can be prevented.

Further, since the guide post fixed to the die guides the blank holder, the positions of the blank holder and the lower die Ceratra die are regulated, and the positions of both do not change, so curved surface forming can be performed with a stable presser.

EXAMPLE Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings. FIG. 1 is a sectional view of the embodiment of the present invention.

15 is an upper die set, 16 is an upper hanger that is fixed to the upper die set 15, and a blank holder 18 is hung thereon, 19
is fixed to the upper die set with a punch, 2o is fixed to the die 22 with a guide post, and 21 is fixed to the lower die set with a lower hanger to prevent the die 22 from lifting up.

23 is lifting the die 22 with a pad and at the same time lifting up the molded shadow mask 2; 24 is the upper stopper fixed to the blank holder 18; 25 is the 24
27 is a cushion rod that pushes up the pad 24 and is fixed to the lower die set 26 by a lower stopper opposite to the lower stopper.

The shadow mask molding die constructed as described above in FIG.
Next, the upper die set 15 is lowered and the punch 19 hits the flat shadow mask 1 to form a curved surface as shown in FIG.
Since the guide post 2o fixed to the die 2 with a screw 29 guides the blank holder 18, the positions of the blank holder 18 and the die 22 are regulated and do not change. When the upper die set 15 is further lowered, the upper stomper 24 hits the lower stopper 25 and the blank holder 18 stops descending.When the upper die set 15 is further lowered, the die 22 is lowered as the bat 23 is lowered.
stops against the upper surface of the lower die set 26, as shown in Figure 3. At this position, there is a gap between the blank holder 18 and the die 22, the amount of which is S'-5=C, and S≧S. ′, there is no gap.

When descending further, the outer periphery of the shadow mask is molded with the gap between the blank holder 18 and the die 22 intact, but the gap between the blank holder 18 and the die 22 prevents the blank holder 18 from pressing down on the mask, resulting in less molding resistance.
- Can be formed by reducing the expansion of the electron beam passage hole.

As it descends further, it reaches the bottom dead center as shown in Figure 4, and the punch 1
9 and band 23 determine the curved surface.

Next, when the upper die set 15 rises and the blank holder 18 rises above the edge height of the shadow mask, as shown in FIG. Push up to complete one cycle. This is Figure 6.

Effects of the Invention As described above, in the present invention, the gap between the blank holder and the die can be arbitrarily determined and maintained during the shadow mask forming process, and processing can be performed while preventing deformation of the electron beam passage hole. has a big effect. Further, in order to eliminate misalignment between the blank holder and the die, a guide post is fixed to the die to guide the blank holder and adjust its position, so that changes in position during mass production can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a mold for forming a shadow mask according to an embodiment of the present invention, FIGS. 2 to 6 are process diagrams of the shadow mask, and FIG. 8 is a plan view of the lower mold, FIG. 9 is a perspective view of the flat shadow mask, FIG. 10 is a perspective view of the molded shadow mask, and FIG.
Figure 12 is an enlarged view of part a in the figure, Figure 12 is an enlarged view of part b in Figure 10, Figure 13 is a sectional view of a conventional shadow mask mold, and Figure 14 is an enlarged view of part a of the figure.
17 are processing process diagrams of a conventional shadow mask molding die, FIG. 18 is a top plan view of the conventional shadow mask molding die, and FIG. 19 is a bottom plan view of the same mold. 15... Upper die set, 16... Upper hanger, 17... Spring, 18...
・Blank holder, 19... Punch, 2o・
...Guide boss, 21...Lower hanger, 22...Die, 23...Pad, 24...Upper stopper, 26・・・・・・
Lower stopper, 26...Lower die set, 27.
...Cushion rod, 28...Nest bin. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Fig. 7 Fig. 8 Fig. 9 Fig. 11 Fig. 12 -ノ (o, J de' 7---7 alink " 8-1-) nige<zo・outside 1/---Hun'/-L f2-ichishin 4, ru) !3---non Str: af4-11grishigonnsoY" Figure 14 Figure 15 Figure 16

Claims (2)

[Claims] (1) A blank holder that prevents wrinkles from appearing around the shadow mask when forming a shadow mask into a curved surface; a punch that is slidably disposed within the blank holder and projects out the curved surface of the shadow mask on a flat plate; a die that molds a flat shadow mask corresponding to a blank holder; a pad that supports and floats the die and takes out the formed shadow mask; a stopper that floats the blank holder during molding and maintains a gap with the die; A shadow mask molding die comprising a lower die set for fixing the stopper. (2) In order to maintain the positional accuracy of the blank holder and die, a post is fixed to the die, and a guide hole is provided in the blank holder and the lower mold holder facing the post to allow them to slide together, so that the press is slightly tilted during press forming. 2. The shadow mask molding die according to claim 1, wherein the blank holder and the die are aligned in position even if there is a difference.