JPH10192996A - Method for forming shadow mask and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably form a shadow mask with high quality without relating uniform or un-uniform friction resistance between a raw material of the shadow mask, an outer punch and a die. SOLUTION: An inner punch 54 and an outer punch 55 are advanced at the same time to the inside of a die 33 through a shadow mask raw material 12 and pressed to a knock-out 34. As the shadow mask raw material 12 is clamped with the inner punch 54 and the knock-out 34, the outer punch 55 is only separated and moved from the shadow mask raw material 12. As the shadow mask raw material 12 is clamped with the inner punch 54 and the knock-out 34, the shadow mask raw material 12 is broken away and moved from the inside of the die 33. After the outer punch 55 is separated and moved from the shadow mask raw material 12 and the shadow mask raw material 12 is broken away and moved from the inside of the die 33, the inner punch 54 is separated and moved from the shadow mask raw material 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a shadow mask used for a color cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, a shadow mask molding apparatus used for a color cathode ray tube has a lower mold 1 and an upper mold 2 as shown in FIG. 5, and the lower mold 1 corresponds to the shape of the mask portion of the shadow mask. It has a die 3 having a forming hole 3a, a knockout 4 disposed in the forming hole 3a, and the like, and an upper die 2 includes a punch 5 corresponding to a mask portion shape of a shadow mask and a blank disposed on the outer periphery of the punch 5. It has a holder 6 and the like.

Then, a shadow mask material 7 is loaded between the lower mold 1 and the upper mold 2 and has a mask portion and a skirt portion bent from the periphery of the mask portion through a molding process shown in FIG. A shadow mask (similar to the shadow mask shown in FIG. 3, but FIG. 3 is a view of an embodiment of the present invention) is press-formed.

[0004] That is, in FIG. 4, a wrinkle holding step (see FIG. 4 (a)) for holding the peripheral portion of the shadow mask material 7 between the die 3 and the blank holder 6, and pressing the punch 5 against the shadow mask material 7. A curved surface overhanging process for performing a curved surface overhanging process between the mask portion 7a and the skirt portion 7b of the shadow mask (see FIG. 4B). A step of narrowing down the portion 3a (see FIG. 4 (c)), a step of moving the punch 5 to the bottom dead center of the press and forming a skirt portion 7b between the side surface of the punch 5 and the forming hole 3a of the die 3 ( 4 (d)), punch 5
(See FIG. 4 (e)), a knock-out raising step of raising the knockout 4 to release the shadow mask material 7 upward from the molding hole 3a of the die 3 (see FIG. 4 (e)). The shadow mask is press-formed through the process shown in FIG.

[0005]

However, the conventional shadow mask forming method and apparatus have problems in the punch raising step shown in FIG. 4E and the knockout raising step shown in FIG. 4F.

That is, in the punch lifting step shown in FIG. 4E, the punch 5 is lifted and separated from the shadow mask material 7, but the frictional resistance is formed between the side surface of the punch 5 and the skirt portion 7b of the shadow mask material 7. Occurs. There is no problem if the frictional resistance is uniform over the entire circumference of the punch 5 and the skirt portion 7b. However, if there is a non-uniform frictional resistance even at one location, the shadow mask material 7 is deformed and the mask 7a is masked. The problem that the curved surface becomes unstable occurs.

In the knockout raising step shown in FIG. 4F, the knockout 4 is raised to
Is removed upward from the forming hole 3a of the die 3, but frictional resistance is generated between the skirt portion 7b of the shadow mask material 7 and the forming hole 3a of the die 3. This frictional resistance is the skirt
There is no problem as long as it is uniform over the entire circumference of the die 7b and the die 3. However, if there is a non-uniform frictional resistance even at one location, the shadow mask material 7 is deformed and the mask curved surface of the mask portion 7a becomes unstable Problem arises.

An object of the present invention is to provide a method and an apparatus for forming a shadow mask capable of stably forming a high-quality shadow mask.

[0009]

SUMMARY OF THE INVENTION A method and apparatus for forming a shadow mask according to the present invention comprises the steps of simultaneously causing an inner punch and an outer punch to enter the inside of a die via a shadow mask material and to press against a knockout; A step of moving only the outer punch away from the shadow mask material while holding the shadow mask material by knockout, and a step of moving the inner punch away from the shadow mask material after moving the outer punch away from the shadow mask material. Is provided. By moving the outer punch away from the shadow mask material while holding the shadow mask material between the inner punch and the knockout, high quality is achieved regardless of whether the frictional resistance between the outer punch and the shadow mask material is uniform or non-uniform. Is formed stably.

[0010] Further, the punch body enters the inside of the die via the shadow mask material and is pressed against the knockout, and the shadow mask material is held from the inside of the die while holding the shadow mask material between the punch body and the knockout. The method includes a step of separating and moving, and a step of separating and moving the punch body away from the shadow mask material after separating and moving the shadow mask material from the inside of the die. Then, while holding the shadow mask material between the punch body and the knockout, the shadow mask material is moved away from the inside of the die to achieve high quality regardless of whether the frictional resistance between the shadow mask material and the die is uniform or non-uniform. Is formed stably.

Moreover, while holding the shadow mask material between the inner punch and the knockout, only the outer punch is moved away from the shadow mask material,
By moving the shadow mask material away from the inside of the die, a high-quality shadow mask can be stably formed regardless of whether the friction resistance between the shadow mask material and the outer punch and the die is uniform or non-uniform.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a shadow mask forming method and apparatus according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a method of forming a shadow mask (a) to (d).
FIG. 2 is a sectional view of a shadow mask forming apparatus, and FIG. 3 is a perspective view of the shadow mask.

FIG. 3 shows a shadow mask 11 of a color CRT. The shadow mask 11 is formed by pressing a shadow mask material 12 such as a metal sheet material, and has a mask portion 14 having a large number of electron beam passage holes 13 and a skirt portion 15 around the mask portion 14. doing.

FIG. 2 shows a press forming machine 16 as a forming apparatus for the shadow mask 11. The lower table 17 and the upper table 18 of the press forming machine 16
20, a lower mold 21 and an upper mold 22 are respectively attached. The lower die 21 and the upper die 22 are relatively closed and opened by the relative opening and closing movement of the lower table 17 and the upper table 18.

The lower die 21 has a lower die plate 31 held by the clamp 19, and a die having a forming hole 32 inside the upper part of the lower die plate 31 corresponding to the outer peripheral shape of the mask portion 14. A knockout 34 is provided to be fitted into the forming hole 32 of the die 33 so as to be vertically movable.

The die 33 includes a column-shaped balancing block 35 erected on the lower mold plate 31 and a stopper bolt.
It is supported movably up and down by 36, etc., and a stopper bolt
The rising position with respect to the lower mold plate 31 is regulated by the 36, and the lowering position is regulated by contact with the die spacer 37 disposed on the lower mold plate 31.

The knockout 34 has a pressing edge at the periphery of the upper surface.
A concave portion 39 is formed in the center of the upper surface and a die spacer larger than the forming hole 32 of the die 33 on the lower surface.
A small knockout flange 40 is formed from the inside of 37, and the knockout flange 40 is supported by a plurality of die cushion pins 41 that penetrate the lower mold plate 31 so as to be vertically movable.

The upper surface of the die 33 and the knockout 34
The upper surface of the holding edge portion 38 is formed into a curved surface corresponding to the surface shape of the mask portion 14.

A plurality of cylinders 43 constituting the knockout driving means 42 are arranged at a position inside the die spacer 37 of the lower die plate 31. In each cylinder 43, a working fluid pressure such as hydraulic pressure or pneumatic pressure is guided, and the piston 44 is moved up and down above the lower mold plate 31 (that is, toward the knockout flange 40). Each cylinder 43 has a pipe section 45 formed on the lower mold plate 31 and a pipe section
A switching valve is connected through a pipe such as a tube connected to 45, and working fluid pressure is guided by the switching valve. The switching valve is controlled by control means for controlling the molding device.

The upper mold 22 has an upper mold plate 51 held by the clamp 20. Below the upper mold plate 51, a punch body 52 corresponding to the shape of the mask portion 14, a punch body 52 Blank holders 53 that fit up and down so as to be vertically movable are provided.

The punch body 52 has an inner punch 54 and an outer punch 55. A concave portion 56 is formed in the center of the lower surface of the outer punch 55 so that the inner punch 54 can be relatively vertically moved. A punch portion 57 is formed on the outer periphery of the inner punch 54 so as to be fitted to the outside of the inner punch 54 so as to be relatively vertically movable. An outer punch that fits over the entire lower surface of the inner punch 54 and the outside of the inner punch 54
The lower surface of the punch portion 57 of 55 is formed on curved punch surfaces 54a, 55a corresponding to the surface shape of the mask portion 14.

In the punch portion 57 of the outer punch 55, the width of the tip portion 55b near the punch surface 55a is formed thinner (narrower) than the base portion 55c. When the shadow mask material 12 is sandwiched between the two, the holding range of the inner punch 54 can be widened, and the effect of preventing deformation of the mask portion 14 can be enhanced. Moreover, the width of the punch portion 57 is narrowed only by the tip portion 55b, and the base portion 55c of the punch portion 57 is formed thicker (wider) than the tip portion 55b.
57 strength can be secured.

The inner punch 54 is supported by a punch driving means 58 so as to be vertically movable. The punch driving means 58 has a spring (not shown) for urging the inner punch 54 upward with respect to the outer punch 55, and has a plurality of cylinders 59. The piston 60 of each cylinder 59 Is connected to the inner punch 54 so as to be vertically movable. In each cylinder 59, a working fluid pressure such as hydraulic pressure or pneumatic pressure is guided and piston 60
Is moved to move the inner punch 54 downward against the bias of the spring when each cylinder 59 is operated (when pressurized), and when the cylinder 59 is not operated (when depressurized) by the bias of the spring. Is moved upward. A switching valve is connected to each cylinder 59 through a pipe 61 formed on the upper die plate 51 and a pipe such as a tube connected to the pipe 61, and the switching valve guides the working fluid pressure. The switching valve is controlled by control means for controlling the molding device.

The outer punch 55 is fixed to the lower surface of the upper plate 51. Since the outer punch 55 is moved up and down integrally with the upper plate 51, the press forming machine 16 that moves the upper plate 51 up and down is configured as a part of punch driving means.

The blank holder 53 has a punch body 52 at the center.
A fitting hole 62 that fits vertically is formed on the outside of the die 33, and the lower surface is formed in a curved surface corresponding to the shape of the upper surface of the die 33, that is, the surface shape of the mask portion 14. An escape groove 63 is formed on the lower side of the inner wall surface of the fitting hole 62.

The blank holder 53 is supported by a plurality of cylinders 64 so as to be vertically movable with respect to the upper die plate 51. The piston 65 of each cylinder 64 is connected to the blank holder 53. In each cylinder 64, a working fluid pressure such as hydraulic pressure or pneumatic pressure is guided to move the piston 65. It is moved up and down with respect to the plate 51. A switching valve is connected to each cylinder 64 through a piping section (not shown) formed on the upper die plate 51 (separately formed below the piping section 61) and piping such as a tube connected to the piping section. And
The switching valve guides the working fluid pressure. The switching valve is
It is controlled by control means for controlling the molding device.

A stopper 66 protrudes from the lower surface of the blank holder 53 at a position facing the balancing block 35 erected from the lower mold plate 31.

On the lower surface of the upper die plate 51, an upper die plate
A stopper bolt 67 that regulates the lowering position of the blank holder 53 with respect to 51 is vertically provided.

Next, the press forming process of the shadow mask 11 will be described.

The lower mold 21 and the upper mold 22 are relatively opened, and the shadow mask material 12 is loaded at a predetermined position. In the mold open state, the knockout 34 is raised, and the die 33 is raised via the knockout flange 40, while the inner punch 54 is raised and the punch surfaces 54a, 55a of the inner punch 54 and the outer punch 55 are raised. Are flush with each other, and the blank holder 53 is
It is lower than a.

When the lower mold 21 and the upper mold 22 are relatively closed, first, as shown in FIG. 2 and FIG. 1A (wrinkle pressing step), the blank holder 53 is moved to the shadow mask. It is joined to the outer peripheral portion of the material 12 and sandwiched between the material 33 and the die 33. After the blank holder 53 is joined to the outer peripheral portion of the shadow mask material 12 and is sandwiched between the die 33 and the die 33, the die 33 and the knockout 34 are pushed down in the sandwiched state.

While the blank holder 53 is descending,
Stopper 66 of blank holder 53 is balancing block
35, and the lowering of the blank holder 53 is regulated. Therefore, the lowering of the die 33 and the knockout 34 is also stopped.

After the lowering of the blank holder 53 is stopped, the lowering of the upper die plate 51 is continued. Therefore, the lowering of the punch body 52 is continued, that is, the inner punch of the punch body 52.
Simultaneous lowering of 54 and outer punch 55 continues, and Fig. 1 (b)
As shown in (1) (curved surface overhanging step), the punch body 52 is pressed against the shadow mask material 12, and the curved surface overhanging process between the mask portion 14 and the skirt portion 15 of the shadow mask 11 is performed.

Further, the lowering of the punch body 52 is continued, and the die 33 and the knockout 34 are lowered via the shadow mask material 12 as shown in FIG.
In the punch body 52, the shadow mask material 12 is formed in the die hole of the die 33.
It is narrowed down to 32.

While the die 33 is descending, the die spacer
Since the descent is regulated by contacting the 37, the shadow mask material 12 is narrowed down to the forming hole 32 of the die 33 by the punch body 52,
As shown in FIG. 1D (step of reaching the bottom dead center of the press), the peripheral portion of the shadow mask material 12 is moved between the punch body 52 and the die 33 until the bottom dead center of the upper die plate 51 is reached. And the skirt portion 15 is formed.

When the upper die plate 51 reaches the bottom dead center of the press, the piston 44 of each cylinder 43 is pushed downward by the lower surface of the knockout flange 40.

Next, the moving direction of the upper die plate 51 which has reached the bottom dead center of the press is reversed and raised. At this time, the cylinders 59 supporting the inner punch 54 are operated, and as shown in FIG. 1 (e) (outer punch raising step), the outer punch 55 is raised integrally with the upper die plate 51. The inner punch 54 is pressed downward, and the state in which the sandwich of the shadow mask material 12 with the knockout 34 is continued. Accordingly, while the shadow mask material 12 is sandwiched between the inner punch 54 and the knockout 34, the outer punch 55 that is in contact with the inner surface of the skirt portion 15 is moved upward away and is separated.

After the outer punch 55 is moved away from the skirt portion 15 and separated, the cylinders 43 below the knockout flange 40 are operated, and as shown in FIG. ), Knockout 34 is pushed up. At this time, the inner punch 54
Rises integrally with the upper die plate 51 at the operation limit point of each cylinder 59, that is, at the time when the piston 60 is extended (downward) most. Therefore, while holding the shadow mask material 12 between the inner punch 54 and the knockout 34, the outer surface of the skirt portion 15 of the shadow mask material 12 is moved upward and away from the forming hole 32 of the die 33 with which the shadow mask material 12 contacts, and is separated. You.

At this time, even if the skirt portion 15 of the shadow mask material 12 detached upward from the forming hole 32 of the die 33 is inclined outward by the spring-back action, the blank holder is not removed.
The skirt portion 15 does not come into contact with the blank holder 53 by entering the escape groove portion 63 into 53.

Each cylinder 43 pushed up by the knockout 34
1 (g), the knockout 34 stops rising, and the cylinders 59 supporting the inner punch 54 are moved to the operating limit point, i.e., when the piston 44 extends (rises) most. When activated, the inner punch 54 is raised.

Then, as the upper mold plate 51 continues to move upward, as shown in FIG.
And the upper mold 22 returns to the mold open state.

With the lower mold 21 and the upper mold 22 open, the press-formed shadow mask 11 is taken out.

As described above, while the shadow mask material 12 is held between the inner punch 54 and the knockout 34, only the outer punch 55 is moved away from the shadow mask material 12, and the shadow mask material 12 is separated from the inside of the die 33. By moving it, the shadow mask material 12
Uniform frictional resistance between the outer punch 55 and the die 33,
The high-quality shadow mask 11 can be formed stably regardless of unevenness.

[0045]

According to the shadow mask molding method and apparatus of the present invention, the outer punch and the shadow are moved by moving only the outer punch away from the shadow mask material while holding the shadow mask material between the inner punch and the knockout. A high-quality shadow mask can be stably formed regardless of whether the frictional resistance with the mask material is uniform or non-uniform.

Further, by moving the shadow mask material away from the inside of the die while holding the shadow mask material between the punch body and the knockout, regardless of whether the frictional resistance between the shadow mask material and the die is uniform or non-uniform. A high quality shadow mask can be formed stably.

Further, while holding the shadow mask material between the inner punch and the knockout, only the outer punch is moved away from the shadow mask material.
By moving the shadow mask material away from the inside of the die, a high-quality shadow mask can be stably formed regardless of whether the friction resistance between the shadow mask material and the outer punch and the die is uniform or non-uniform.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a shadow mask forming method according to an embodiment of the present invention in the order of (a) to (h).

FIG. 2 is a cross-sectional view of a shadow mask forming apparatus according to the first embodiment;

FIG. 3 is a perspective view of the same shadow mask.

FIG. 4 shows a conventional shadow mask molding method (a) to (f).
FIG.

FIG. 5 is a sectional view of a conventional shadow mask forming apparatus.

[Explanation of symbols]

 12 Shadow mask material 33 Die 34 Knockout 42 Knockout drive means 52 Punch body 54 Inner punch 55 Outer punch 58 Punch drive means

Claims (6)

[Claims] 1. A step of simultaneously moving an inner punch and an outer punch into the inside of a die via a shadow mask material and pressing against a knockout, and shadowing only the outer punch while holding the shadow mask material between the inner punch and the knockout. A method of forming a shadow mask, comprising: moving the outer punch away from the shadow mask material; and moving the inner punch away from the shadow mask material after moving the outer punch away from the shadow mask material. 2. A step of causing the punch body to enter the inside of the die via the shadow mask material and pressing the knockout, and holding the shadow mask material between the punch body and the knockout while removing the shadow mask material from the inside of the die. A method of forming a shadow mask, comprising: a step of separating and moving; and a step of separating and moving the punch body away from the shadow mask material after the shadow mask material is separated from the inside of the die. 3. A step of simultaneously moving the inner punch and the outer punch into the die through the shadow mask material and pressing against the knockout, and shadowing only the outer punch while holding the shadow mask material between the inner punch and the knockout. Moving the shadow mask material away from the inside of the die while holding the shadow mask material between the inner punch and the knockout, and moving the outer punch away from the shadow mask material and shadow mask Removing the material from the inside of the die and moving the inner punch away from the shadow mask material. 4. A die, a punch body having an inner punch and an outer punch which are inserted into the die via a shadow mask material, and a shadow which is disposed inside the die and is pressed by the punch body. A knockout receiving the mask material, the inner punch and the outer punch simultaneously enter the inside of the die via the shadow mask material to be pressed against the knockout, and only the outer punch while holding the shadow mask material between the inner punch and the knockout And a punch driving unit for moving the inner punch away from the shadow mask material after moving the inner punch away from the shadow mask material. 5. A die, a punch body which enters inside the die via a shadow mask material, and a knockout which is arranged inside the die and receives a shadow mask material pressed by the punch body. The punch body entered the inside of the die via the shadow mask material and was pressed against the knockout, and the shadow mask material was separated from the inside of the die while holding the shadow mask material between the punch body and the knockout. A punch driving unit for moving the punch body away from the shadow mask material later, and a knockout driving unit for moving the knockout integrally with the punch body when moving the shadow mask material away from the inside of the die. An apparatus for forming a shadow mask, comprising: 6. A die, a punch body having an inner punch and an outer punch which are inserted into the die via a shadow mask material, and a shadow disposed inside the die and pressed by the punch body. A knockout receiving the mask material, the inner punch and the outer punch simultaneously enter the inside of the die via the shadow mask material to be pressed against the knockout, and only the outer punch while holding the shadow mask material between the inner punch and the knockout Punch driving means for moving the inner punch away from the shadow mask material after moving the shadow mask material away from the inside of the die and moving the shadow mask material away from the inside of the die, and moving the shadow mask material away from the inside of the die When knocking Molding apparatus of the shadow mask, characterized in that it comprises a knockout drive means for moving out the punch member integrally.