JPH04149927A - Manufacture of electron gun electrode - Google Patents

Abstract

PURPOSE:To smoothly perform the plastic deformation of a metal thin plate by forming the shape of the portions of a pair of tools to be brought into contact with the surface of the coining work section of an electron gun electrode into a protruded spherical shape when the metal thin plate is pinch-pressed by a pair of compressing tools for coining to the preset thickness. CONSTITUTION:A stainless steel plate is pressed by a pair of compressing tools 11, 21, and a coining work section 4 with the preset thickness thinner than the raw material thickness of the steel plate is formed between spherical faces 16, 23 provided on the tools 11, 21. Electron beam passing holes 12 are protrusively bored on the work section 4 thus molded. The portions of the tools 11, 21 to be brought into contact with the surface of the work section 4 are formed into the protruded spherical faces 16, 23, and the plastic deformation of the steel plate is facilitated. Pads smoothly flow outward centering on the center section of the work section 4 at the time of coining, no excess phenomenon of pads occurs, and the coining machining to 30-50% of the raw material thickness can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing an electron gun electrode for a cathode ray tube.

(Prior Art) FIGS. 3 to 5 show a No. 1 GRID electrode, which is an electron gun electrode 1 used in a color cathode ray tube. This electrode 1 made of a thin metal plate has three electron beam passage holes 2 formed therein, and an annular bead portion 3 surrounding these electron beam passage holes 2. Inside, the peripheral portion of each electron beam passage hole 2 is subjected to a coining process so as to be thinner than the thickness of the material, forming a coining process part 4.

The surface of this coining processing part 4 needs to be parallel to the cathode of the electron gun and other electrodes, and the coining processing part 4
It is desired that the surface of the substrate has good parallelism and flatness.

Here, conventional coining processing will be explained with reference to FIGS. 7 and 8.

11 is a cylindrical first compression tool on the punch side;
On the lower surface of the compression tool 11, a truncated conical protrusion 12 is formed at the center, and the tip surface of this protrusion 12 meets the central flat surface 1.
3. The peripheral surface of the protrusion 12 is a tapered surface 14, and the outside of this tapered surface 14 is a peripheral flat surface 15. Also, 21
2 is a cylindrical second compression tool on the die side, and the entire upper surface of the second compression tool 21 is a flat surface 22. Then, the first compression tool 11 on the upper side of the figure and the second compression tool 2 on the lower side of the figure.
1 approach or separate coaxially in the vertical direction. In addition,
The first compression tool 11 has a slightly larger diameter than the second compression tool 21. Furthermore, a bead forming tool 31 for forming the beat portion 3 of the electron gun electrode 1 is fitted onto the outer periphery of the first compression tool 11 .

Then, as shown in Fig. 7, both compression tools 1! , 21, and these two compression tools I+
, 2+ is strongly pressed against the thin metal plate from both sides to perform the coining process. At the same time, the bead portion 3 of the electron gun electrode 1 is formed by the tip of the bead forming tool 31 that protrudes downward in the figure from the first compression tool 11 . After that, the electron beam passage hole 2 is bored. During coining processing, the first
The coining part 4 of the electron gun electrode 1 is formed by being compressed by the central flat surface 13 of the compression tool 11 and the flat surface 22 of the second compression tool 21, and is guided by the tapered surface 14 from here to the direction indicated by the arrow. The excess meat flows as shown.

Incidentally, in recent years, in order to improve the cutoff characteristics and focus quality of cathode ray tubes, the coining processing section 4 has been
There is a tendency for the wall thickness of steel to become thinner, and there is an increasing demand for this wall thickness to exceed the limit of plastic deformation.

However, in the conventional method, the thickness of the coining part 4 has a limit of about 5θ% of the material thickness, and if it is less than that, as shown in FIG. As a result, a bulge 5 was generated on the lower side of the coining portion 4 as shown in the figure, resulting in deterioration of the flatness.

Therefore, conventionally, as a method of absorbing the excess meat during the coining process, a method has been adopted in which an escape hole is previously drilled in the center of the portion that will become the coining process part 4 and the excess meat is absorbed into this hole.

However, in a high-definition electron gun such as a display tube, the electron beam passage hole 2 that is drilled later is extremely small, and if the relief hole for absorbing excess material is made large, the relief of the excess material will be uneven. In this case, the escape hole overlaps the electron beam passage hole 2, and the roundness of the electron beam passage hole 2 deteriorates, making it impossible to obtain good electron gun characteristics.

In addition, as another method, after the first coining process, an annealing process is performed to soften the material, and then the coining process part 4
There is also a method of obtaining the predetermined dimensions by performing a second coining process to thin the material, but including an intermediate annealing step causes a significant increase in manufacturing costs, and is not necessarily a good method.

(Problem to be solved by the invention) In a manufacturing process in which the area around the electron beam passage hole of an electron gun electrode is locally thinned by coining, especially when the thickness of the coined part is 50% or less of the material thickness. , As mentioned above, in the conventional method of performing coining using a compression tool whose surface in contact with the surface of the coining processing part is a flat surface, there is no escape for the excess metal when the compression tool is applied with strong pressure, and bulges occur. There was a problem that caused deterioration of flatness. In addition, with the method of drilling extra-thickness relief holes, if the extra-thickness relief becomes uneven or the relief hole is too large, holes may be chipped when drilling the electron beam passage holes later. There was a problem that this caused the roundness to deteriorate. Furthermore, the method of performing an annealing process after the first coining process and then performing the second coining process has problems such as increased production costs.

The present invention aims to solve the above-mentioned problems, and provides a high-quality, high-precision, low-cost electron gun electrode in which the periphery of the electron beam passage hole is coined to, for example, 50% or less of the material thickness. The purpose of the present invention is to provide a method for manufacturing an electron gun electrode.

[Structure of the invention]

(Means for Solving the Problems) In the method for manufacturing an electron gun electrode of the present invention, a thin metal plate is sandwiched between a pair of compression tools and subjected to a coining process to locally form the thin metal plate into a thin layer. When drilling an electron beam passage hole in a coined portion of a thin metal plate, the shapes of the portions of both compression tools that contact the surface of the coined portion are both convex spherical shapes, and This process involves coining a thin metal plate to a predetermined thickness.

(Function) In the method for manufacturing an electron gun electrode of the present invention, a metal thin plate is sandwiched and pressed between a pair of compression tools to perform coining processing to a predetermined thickness. Because the shapes of the parts in contact with the surface of the coining part are both convex spherical shapes, the press load acts intensively on the center part of the surface of the coining part, and the excess material is removed from the coining part. Since it becomes easier to flow outward from the center of the section, plastic deformation of the thin metal sheet occurs smoothly.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 5. In the following description, the same reference numerals are given to parts corresponding to those of the conventional example described above, and detailed description thereof will be omitted.

3 to 5 show an example of the electron gun electrode 1 manufactured by the manufacturing method of the present invention.

This electrode 1 is formed by pressing a thin metal plate, for example, a stainless steel plate with a material thickness of 0.18 mm, and has an electron beam passage hole 2, a heating part 3, and a thin coining part 4 formed therein, or by this coining process. The diameter of portion 4 (coining diameter) φd is 1. Omm, coining processing section 4
The thickness (coining thickness) t is 0.06 mm.

FIG. 1 shows a first compression tool 1 used in the manufacturing method of the present invention.
1 and a second compression tool 21 are shown.

On the lower surface of the first compression tool (1) on the punch side, a protrusion j2 is formed in the center, and the curved surface of this protrusion 12 forms the tapered surface 1.
4. The outer side of this tapered surface 14 is a peripheral flat surface 15, but the shape of the tip end surface of the protrusion 12 in contact with the surface of the coining part 4 is not a flat surface but a convex spherical surface 16. . Further, the upper surface of the second compression tool 21 on the die side that is in contact with the surface of the coining processing section 4 is also not a flat surface but a convex spherical surface 23.

The spherical steps hl and h2 of these spherical surfaces 16.23 are approximately 0.
005~Q, 0] mm. Note that both spherical surfaces 16 and 23 are centered on the central axis of the compression tools II and 21.

In addition, in FIG. 2, 31 is a beat forming tool.

Then, in the manufacturing process of the electron gun electrode 1, as shown in FIG. 2, a stainless steel plate is sandwiched between both compression tools 11 and 21 and subjected to coining processing. That is, the stainless steel plate is pressed by both compression tools I+ and 2+, and a coined part 4 having a predetermined thickness thinner than the material thickness is formed on the stainless steel plate between the spherical surfaces 16 and 23 of these compression tools 11 and 21. . Thereafter, an electron beam passage hole 2 is bored in the coining portion 4 locally formed in the stainless steel plate in this way.

When performing coining using the compression tools II and 21 as described above, the portions of both compression tools II and 21 that are in contact with the surface of the coining processing portion 4 are both convex spherical surfaces 16.
．． 23, the stainless steel plate is susceptible to plastic deformation (as shown by the arrow in Fig. 2, the excess metal flows smoothly outward from the center of the coining section 4 as the coining process progresses). As a result, it becomes possible to perform coining processing of approximately 30 to 50% of the material thickness without causing excess material.In this example, the material thickness is 0.18 mm, and the coining thickness is 0.18 mm. t is 0. (
Since the coining thickness is 16 mm, the coining thickness t is approximately 34 mm of the material thickness.
%.

Along with this, since the shape of the portion of both compression tools 11.2+ in contact with the surface of the coining portion 4 is a convex spherical surface 16.23, the press load is applied to the central portion of the surface of the coining portion 4. In other words, concentrate on the parts that require the most load.

This effectively works to smooth the plastic deformation of the stainless steel plate, and also reduces the burden on the compression tool 11, 21, resulting in a significant effect of improving tool life.

By not causing the excess thickness phenomenon, the parallelism and flatness of the coined portion 4 of the electron gun electrode 1 are good, and as a result, high quality and high precision electron gun characteristics can be obtained.

Further, manufacturing costs can be reduced by improving the life of the compression tools II and 2+ and by eliminating the need for an intermediate annealing process.

FIG. 6 shows another embodiment of the present invention, in which the present invention is applied not to coining from one side as in the previous embodiment, but to coining from both sides. That is, in this embodiment, the second compression tool 11 also has a protrusion 24 similar to the protrusion 12 of the first compression tool 21, and between the protrusions 12 and 24 of both compression tools N, 12. The coining process is applied. and,
The tip surfaces of the protrusions 12 and 24 in contact with the surface of the coining portion 4 in both compression tools 11.12 are both convex spherical surfaces 16.25.

In this way, even in the case of coining processing from both sides, the spherical surfaces 16, 25 formed on both compression tools II, 12.
Accordingly, the same effects as those of the above embodiment can be obtained.

[Effects of the Invention] According to the present invention, in the method for manufacturing an electron gun electrode in which an electron beam passing hole is formed in the coined portion after coining a metal thin plate, the coining in a pair of compression tools for coining is performed. The shapes of the parts in contact with the surface of the machined part are both convex spherical shapes, and the thin metal sheet is coined to a predetermined thickness between both compression tools, so that the plastic deformation of the thin metal sheet at that time is performed smoothly. Therefore, while maintaining good parallelism and flatness of the coined part of the electron gun electrode, the wall thickness of the coined part can be reduced to, for example, 30 mm.
50%, therefore, it is possible to provide an electron gun electrode that can obtain high quality electron gun characteristics. Further, manufacturing costs can be reduced by improving the life of the compression tool and eliminating the need for an intermediate annealing process.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the electron gun electrode manufacturing method of the present invention, in which FIG. 1 is a front view of a compression tool, FIG. 2 is a sectional view for explaining the operation, and FIG. This figure is a plan view of the electron gun electrode, FIG. 4 is a partially sectional front view of the electron gun electrode, and FIG. 5 is an enlarged view of the vicinity of the coining part in FIG. 4. Further, FIG. 6 is a sectional view for explaining the operation of another embodiment of the method for manufacturing an electron gun electrode of the present invention. Furthermore, FIGS. 7 and 8 show an example of a conventional method for manufacturing an electron gun electrode, with FIG. 7 being a front view of a compression tool, and FIG. 8 being a sectional view for explaining the operation. 1... Electron gun electrode, 2... Electron beam passing hole, 4... Coining processing section, 11... Compression tool, 16... Spherical surface, 2
1... Compression tool, 23... Spherical surface, 25... Spherical surface. ``i''

Claims (1)

[Claims] (1) An electron gun that applies a coining process to a thin metal plate by sandwiching it between a pair of compression tools, forming the thin metal plate locally to be thin, and then drilling an electron beam passage hole in the coining process part of the thin metal plate. In the method for manufacturing an electrode, the shapes of the portions of the compression tools that contact the surfaces of the coining portions are both convex spherical shapes, and the thin metal plate is coined to a predetermined thickness between the compression tools. A method for manufacturing an electron gun electrode characterized by: