JPH0210625A - Manufacture of electron gun electrode for cathode-ray tube - Google Patents

Abstract

PURPOSE:To increase the height of a cylinder section and manufacture an electrode with high performance at a low cost by forming a deformed cup by drawing then concurrently performing the molding of the height of the cup and the forming of the stretched section with the preset inner diameter. CONSTITUTION:The preset plank 30 is drawing-processed to form a deformed cup 31. A lower hole 32 is formed, then the molding to form the cup 31 to the preset height and the stretching to form a stretched section 33 with the preset inner diameter are concurrently performed. The deformation generated when hydrogen annealing is performed is suppressed by this method, the plane flatness of the top section and the degree of parallelization between the top section and a bottom flange section can be maintained with high precision. A lower hole 34 is formed, burring is performed to form a cylinder section 35. The tip section 36 of the cylinder is expanded, edge cutting is performed to form a bottom flange section 37. An electrode with a high circular top section and high performance is obtained at a low cost.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for manufacturing an electron gun electrode for a cathode ray tube.

(Prior Art) Generally, an electron gun for a cathode ray tube, for example, an in-line unitized electron gun for a cathode ray tube, is constructed as shown in FIG.

That is, from the cathode (not shown) side that emits the electron beam, a first electrode 1 that controls the electron beam, a second electrode 2 that accelerates the electron beam, a third electrode 3 that constitutes the sub-lens electrode, and a main electrode. A fourth electrode 4, a fifth electrode 5, and a sixth electrode 6 constituting the lens electrode are arranged in this order, and a convergence cup 7 is attached to the upper part of the sixth electrode 6.
The device is configured to focus the electron beam on the phosphor screen and reproduce the image. In addition, each electrode is baked and fixed to bead glass 8, and by this bead glass 8,
The spacing between the respective electrodes is maintained at a predetermined spacing.

In the electron gun having the above configuration, the electron gun electrode, for example, the fifth
As shown in FIGS. 3 and 4, the electrode 5 has three cylindrical electron beam passing holes 11.1 at a predetermined interval on the top.
2.13 is formed, and is an irregularly shaped cup electrode having a predetermined height and having a flange portion 14 formed at the bottom to be embedded in the bead glass 8.

In the fifth electrode 5, the cylindrical electron beam passage hole 11
．． 12.13 is for forming an electric field forming the main lens portion, and this cylindrical electron beam passing hole 11
．． 12. If the height of the cylindrical part of 13 is low, the electric field will be
Since the electron gun is strongly influenced by its outer peripheral side wall and is disturbed, causing deterioration of focus characteristics, it is necessary to make the height of this cylindrical portion as high as possible in order to obtain an electron gun with good focus characteristics.

Therefore, various proposals have been made regarding methods for integrally molding irregularly shaped cup components in which the height of the cylindrical portion is as high as possible.

For example, JP-A-58-24741 proposes a method for manufacturing an electron gun electrode for a cathode ray tube in which the height of the cylindrical portion is approximately 0.5 to 0.7 times the inner diameter of the cylindrical portion.

That is, in this method, as shown in FIG.
By punching the material plate 20, three pilot holes 21 having a predetermined inner diameter are formed at predetermined intervals (A).

Next, a coining process is performed to make the lower hole edge burr part 22 into a tapered shape (B).

Thereafter, the overhanging process with ironing is performed a plurality of times at the same center position as the center position of the hole punching and coining process to form the overhang part 23 (C).

After that, a burring pilot hole 24 is formed at the same center position as the above-mentioned center position (D).

Next, burring is performed at the same center position as the above center position to form three cylindrical parts 25 (E).

Then, the irregularly shaped cup portion 26 is formed by drawing,
Integrally mold the electrode parts (F).

(Problems to be Solved by the Invention) However, the conventional method described above has the following problems.

That is, when the first overhang process is completed, warpage occurs in the material plate due to distortion during the overhang process. Therefore, when each of the above-mentioned steps is performed, for example, by transfer processing, it becomes extremely difficult to accurately and smoothly transfer to the next steps of overhanging, burring pre-hole processing, burring, and drawing.

This is because when a warped workpiece is gripped by a holding claw attached to the transfer mechanism, the warpage of the workpiece affects the gripping, making the gripping unstable and inaccurate.

Therefore, it cannot be transferred to a fixed position for the next process, and the second and subsequent overhanging operations, burring pilot hole operations, burring operations, etc., cannot be performed at the same center.

In particular, if the burring pilot hole drilling and burring processing cannot be performed at the same center, the length of the cylindrical part will not only be uneven around the entire circumference when burring is performed, but also the burring processing will be performed in an eccentric state. Cracks may occur at the tip.

Even if such a transfer could be carried out smoothly, it would be necessary to drill a pilot hole in the material board and then transfer it to the next step, the first overhanging process, and then align the center of the pilot hole and the center of the first overhang without any positioning. It is very difficult to make them the same.

Therefore, it is preferable to carry out such a process by progressive processing rather than by transfer processing.

However, when manufacturing by progressive processing, the amount of material used increases compared to the case of transfer processing, and the unit cost of parts becomes higher.

In addition, in this method, burring is performed after overhanging multiple times, but the roundness of the burring hole deteriorates due to the effects of machining distortion during the multiple overhanging and burring. There is also. According to experiments conducted by the present inventors, the circularity of the burring holes manufactured by this method was approximately 20 μm using the least squares method. Such deterioration in the roundness of the burring hole has an adverse effect on the focusing performance, and the effect becomes more significant as the diameter of the main lens portion becomes smaller. For example, when the above circularity of approximately 20 .mu.m was evaluated using a cathode ray tube having a main lens diameter of 3.9 .mu.m using the least squares method, it was confirmed that focus failure occurred. As described above, the method of repeating the overhanging process multiple times causes accumulation of processing distortion, resulting in deterioration of focusing performance.

Furthermore, in this method, since the profile drawing process is performed after the burring process, there is also a problem that the flatness of the top surface and the parallelism between the top part and the bottom flange part are not stable. This is because when narrowing down to a cup with an irregular shape, a surplus of material is generated at the top part, and this surplus material improves the flatness of the top surface and the bottom flange during hydrogen annealing to remove oxides from the surface of the cup. This is because the parallelism changes significantly.

The present invention has been made in response to such conventional circumstances, and has good roundness of the cylindrical part, flatness of the top surface, and parallelism between the top part and the bottom flange part, and the height of the cylindrical part is the same as that of the cylindrical part. An object of the present invention is to provide a method for manufacturing an electron gun electrode for a cathode ray tube, which is capable of manufacturing an electron gun electrode for a cathode ray tube with a high performance of about 0.5 to 0.7 times the inner diameter of the tube at a low cost and with high precision. It is.

[Structure of the Invention] (Means for Solving the Problems) That is, the present invention provides an irregularly shaped cup electrode having a cylindrical electron beam passage hole at the top and a flange portion for embedding bead glass at the bottom. In manufacturing, first, an irregularly shaped cup is formed on a material plate by drawing, then a pilot hole with a predetermined inner diameter is formed at the top of the irregularly shaped cup, and then a hole is formed to make the irregularly shaped cup have a predetermined height. A molding process and an overhanging process to form an overhanging part having a predetermined inner diameter are performed at the same time, and then a burring process is performed at the same center position as the overhanging process to form a burring hole having a predetermined inner diameter, and then the burring process is performed to form a cylindrical shape. The burring tip opening is enlarged by a widening process, and then a flange portion of a predetermined shape is formed by an edge cutting process.

That is, in the method of the present invention, first, a blank that is punched or cut into a predetermined shape from a material plate is subjected to irregular drawing processing to form an irregularly shaped cup. In addition, the height of the irregularly shaped cup in this case is 1.2 to 1 of the desired irregularly shaped cup height.
．． It is preferable to set the height to about 4 times.

Next, pilot hole machining is performed to form pilot holes having a predetermined inner diameter at a predetermined center interval on the top of the cup component drawn into the irregular shape. Note that it is preferable that the predetermined center spacing at this time be slightly wider than the center spacing during overhang processing and burring processing, which will be described later.

Next, molding and stretching are performed simultaneously. This molding process is to make the height of the irregularly shaped cup to the desired height, and to form the flatness of the top surface and the parallelism between the top and bottom flange parts with high precision.The overhang process will be described later. This is to enable the desired cylindrical length to be easily formed by the burring process. In addition, performing forming and overhanging at the same time means that the material required for overhanging is not only applied to the center of the overhang, but also deeper (higher) than the desired height of the irregularly shaped cup during irregular drawing.
This is because it absorbs more from the squeezed part.

Note that the inner diameter of the protruding portion at this time is preferably 95% or more of the inner diameter of the cylindrical portion during burring. This is because if the inner diameter of the overhang is small, the corner radius of the root opening of the cylindrical part will become smaller when the burring process is performed, the electrostatic lens will shrink, and the defocusing characteristics will become smaller. be.

In this way, by performing forming and overhanging processes at the same time, it is possible to achieve an overhang height that could not be obtained with conventional overhanging processes, and the surface flatness of the top and the parallelism between the top and bottom flange parts are also high. Accuracy can be maintained.

Next, burring pilot hole processing is performed to form a burring pilot hole at the top of the irregularly shaped cup at the same central position as the above-mentioned overhanging step. Note that if the diameter of the burring hole is small at this time, the burring may exceed the plastic working range and cracks may occur at the opening tip of the cylindrical portion. In addition, since the diameter of the pilot hole formed in the previous process has expanded during overhanging in the previous process, the burring pilot hole cannot be machined unless the burring pilot hole diameter is made larger than this enlarged diameter. The height of the cylindrical portion cannot be formed uniformly around the entire circumference. On the other hand, if the diameter of the burring hole is made too large, the desired height of the cylindrical portion cannot be achieved during burring.

Therefore, according to experiments conducted by the present inventors, the diameter of the burring hole is preferably 66% to 70% of the burring diameter.

Next, a burring process is performed to form a cylindrical part of the desired height, and after this, the opening tip of the cylindrical part is reduced from the predetermined burring inner diameter due to the springback of the material during the burring process, so this part is The mouth is widened from the bottom side.

Then, the bottom flange portion is formed into a desired shape by edge cutting to form an electrode.

(Function) In the method for manufacturing an electron gun electrode for a cathode ray tube according to the present invention, the height of the cylindrical portion can be adjusted to the same level as that of the cylindrical portion without impairing the circularity of the inner diameter of the cylindrical portion, the surface flatness of the top portion, and the parallelism between the top portion and the bottom flange portion. It is possible to manufacture an electron gun electrode with a diameter as high as about 0.5 to 0.7 times the inner diameter of the part, and it is possible to provide a high-performance electron gun. It can also be manufactured by transfer processing,
Manufacturing costs are also low.

(Example) Hereinafter, details of the present invention will be explained with reference to the drawings.

FIG. 1 shows the steps of a method for manufacturing an electron gun electrode for a cathode ray tube according to an embodiment of the present invention.
A predetermined blank 30 is formed from a material by cutting or punching (a).

Next, the predetermined blank 30 is drawn to form an irregularly shaped cup 31. The height of the irregularly shaped cup 31 at this time is approximately 1.2 to 1.4 times the height of the electrode (b).

Next, pilot holes 32 of a predetermined inner diameter are formed at the top of the irregularly shaped cup 31 at a predetermined center interval (C).

At this time, the distance between the centers of the pilot holes 32 is made slightly wider than the distance between the centers of the beam passage holes. For example, a mini-neck tube (φ22.
In the case of the electron gun electrode used in the main lens part (neck of 5), where the beam passing hole center spacing is 4.75 m5, the beam passing hole center spacing is 4.85 mm, and the beam passing hole center spacing is 0.11 mm.
■Make it wider. When performing forming and overhanging after machining the pilot hole, the pilot hole 32 on both sides is removed due to the overhang in the center.
This is because it is concentrated in the center. That is, the lower hole 32
If the distance between the centers is not widened, the pilot holes 32 on both sides will be moved toward the center, making it impossible to perform burring pilot holes at the same center, which will be described later.This will result in cracks at the opening tip of the cylindrical portion during burring. Otherwise, it becomes impossible to make the length of the cylinder part uniform.

Thereafter, a molding process to make the height of the irregularly shaped cup 31 a predetermined height and an elongating process to form an overhanging part 33 having a predetermined inner diameter are performed simultaneously (d). The reason why these processes are performed simultaneously is to suppress deformation that occurs when hydrogen annealing is performed in a post-process, and to maintain highly accurate surface flatness of the top and parallelism between the top and bottom flange. In other words, by performing so-called collision processing, most of the elastic region is changed to the plastic region, and by hydrogen annealing, the portion that changes to the elastic region is reduced, and the surface flatness of the top and the top and bottom flange parts after hydrogen annealing are improved. Suppress changes in parallelism.

Further, the inner diameter of the projecting portion 33 is set to be 95% or more of the inner diameter of the cylindrical portion during burring processing, which will be described later. For example, for a cylinder with an inner diameter of 3.9 mm, it is preferably 3.71 or more, so that the corner radius of the engine mouth where the cylinder is attached will not become small.
Defocus characteristics do not decrease.

After that, a burring pilot hole is processed at the same center position as the above-mentioned overhanging process to form a burring pilot hole 34 (e
).

This is because the part processed by pilot hole processing does not expand uniformly due to forming and overhanging processing, and if burring processing is performed as it is, the cylindrical part cannot be formed uniformly around the entire circumference, and the opening tip of the cylindrical part This is because cracks occur in the parts. This burring pilot hole 34 is formed at the same center position as the overhanging process, and has a larger diameter than the enlarged portion of the pilot hole, and is 66% to 70% of the inner diameter of the cylindrical portion. In this way, cracking at the tip opening of the cylindrical portion does not occur, and the length of the cylindrical portion can be smoothly formed to a desired length. For example, for a cylinder with an inner diameter of 3.9 ms, the burring hole diameter is 2.
．． 57m11~2. It is preferable to set it as Ll+gm.

Next, burring is performed at a predetermined center position interval and at the same center position as the above-mentioned projecting center position to form three cylindrical parts 35 (f).

Thereafter, a mouth widening process is performed to widen the cylindrical tip opening 36 to make it larger than the diameter of the cylindrical portion (g).

This is because when burring is performed, a tapering phenomenon occurs in the cylindrical tip opening 36 formed in the cylindrical part due to the springback that always occurs during plastic processing, and if such an electrode is used as is, the electron beam This is because when assembling the electron gun by inserting the rod into the passage hole, there are few contact areas between the rod and the electrode, which causes problems such as the electrode becoming slanted.

Thereafter, edge cutting is performed to form the bottom flange portion 37 into a desired flange shape (h).

In the method for manufacturing an electron gun electrode for a cathode ray tube according to this embodiment described above, an electrode with a high cylindrical part height of 0.5 to 0.7 times the inner diameter of the cylindrical part is manufactured by transfer processing, which is inexpensive in manufacturing cost. Good circularity within 10μm by least squares method,
The surface flatness of the top of the irregularly shaped cup and the parallelism between the top and the bottom flange were also good.

In this embodiment, an in-line unitized type electron gun has been described, but the method of the present invention can be similarly applied to other types such as a delta type or a monochrome type. Furthermore, although this embodiment has been described as having three electron beam passing holes, the number of electron beam passing holes is not limited to three and may be any number.

[Effects of the Invention] As explained above, according to the present invention, the roundness of the cylindrical portion, the flatness of the top surface, and the parallelism between the top and bottom flange portions are good, and the height of the cylindrical portion is equal to that of the cylindrical portion. Approximately 0.5 to inner diameter
High performance electron gun electrodes for cathode ray tubes with a high performance of approximately 0.7 times,
It can be manufactured at low cost by ordinary transfer processing or the like.

[Brief explanation of the drawing]

Fig. 1 is a process diagram showing a method for manufacturing an electron gun electrode for a cathode ray tube according to an embodiment of the present invention, Fig. 2 is a side view of an in-line unitized electron gun, and Fig. 3 is a modified cup electrode of Fig. 2. 4 is a partially sectional side view of the irregularly shaped cup electrode of FIG. 3, and FIG. 5 is a process diagram showing a conventional method of manufacturing an electron gun electrode for a cathode ray tube. 31・・・・・・・・・Irregular-shaped cup 32...
......... Pilot hole 33 ...... Overhanging portion 34 ...
・・・・・・Burring pilot hole 35・・・・・・・・・
...Cylindrical portion 36...Cylindrical tip opening 37...
・・・・・・・・・Bottom flange part Figure 5 Applicant: Toshiba Corporation Patent attorney Suyama Sa - (b) (e) (f) Figure (h)

Claims (1)

[Claims] (1) In manufacturing an irregularly shaped cup electrode that has a cylindrical electron beam passage hole at the top and a flange portion for embedding bead glass at the bottom, first, an irregularly shaped cup is formed on a material plate by drawing. Next, a pilot hole with a predetermined inner diameter is formed at the top of the irregularly shaped cup, and then a molding process to make the height of the irregularly shaped cup a predetermined height and an overhanging process to form an overhanging part having a predetermined inner diameter are simultaneously performed. Next, burring is performed at the same center position as the overhanging process to form a burring hole having a predetermined inner diameter, and then the burring tip opening, which has been processed into a cylindrical shape by the burring process, is enlarged by widening process, and then edge cutting is performed. A method of manufacturing an electron gun electrode for a cathode ray tube, the method comprising forming a flange portion of a predetermined shape by processing.