JPS6149778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of processing a main lens electrode portion of an electron gun used in a color cathode ray tube.

As is well known, there are two types of electron guns: in-line type and delta type.The in-line type electron gun will be explained below as an example.

In general, the main lens electrode part of an integrated in-line electron gun is as shown in FIGS.
It has a structure in which three lens parts 3 are formed adjacent to each other by burring.

Conventionally, in order to form the lens portion 3, the electrode body 1 is first press-molded, and then a punch 4 having an outer diameter dimension d is attached to the top plate 2 as shown in FIG. 3a.
to form the pilot hole 5 for burring, and then the third
As shown in Figure b, the top plate 2 was placed on a burring die 6 and burred with a burring punch 7 having an outer diameter of D to form three cylindrical lens parts 3. .

However, in such conventional processing methods,
As shown in FIG. 3b, when the burring punch 7 is located inside the lens part 3, the inner diameter of the lens part 3 is equal to the outer diameter D of the burring punch 7. 4, the inner diameter of the tip of the lens part 3 is smaller than the outer diameter D of the burring punch 7.
D', and there was a drawback that both the cylindricity and roundness of the lens portion 3 deteriorated. Also, the burring hole expansion rate d/D in the above conventional processing method
The maximum height H of the lens portion that can be formed is about 1.3 mm. On the other hand, in order to fully play the role of the main lens electrode in an integrated in-line electron gun, the ratio of the inner diameter to the height of the lens part 7 H/D
It is necessary to make it 0.5 or more, and for that purpose, the burring hole expansion ratio needs to be 12% or less. However, it has been extremely difficult to obtain such a high burring hole expansion rate using conventional processing methods.

Therefore, conventionally, in order to obtain the necessary height of the lens part, an auxiliary link 8 was separately manufactured as shown in Fig. 5.
A structure was adopted in which the required height was obtained by fitting and fixing the lens part 3 into the lens part 3. However, in the case of such a structure, the process of assembling the auxiliary link 8 into the lens part 3 is required, which complicates the manufacturing process, while at the same time deteriorating the cylindricity and roundness of the lens part 3, and reducing the number of parts. As the number of electronic guns increases, the accuracy of electron gun assembly deteriorates, reducing the performance of the electron gun, and the product becomes more expensive.

In view of the above-mentioned drawbacks of the prior art, the present invention enables a lens part having a sufficient height to be integrally molded, thereby simplifying the manufacturing process, and also has good cylindricity and roundness of the lens part, making it excellent as an electron gun. It is an object of the present invention to provide a method for processing an electrode body of an electron gun that has high performance and can be manufactured at low cost.

The present invention will be explained below with reference to embodiments shown in FIGS. 6 and 7. Figure 6 shows an in-line electron gun electrode 1 integrally molded with a lens part manufactured by the method of the present invention.
0, and three lens portions 13 are integrally formed on the top plate 12 of the electrode body 11 by a method described later. The inner diameter dimension D and the height of the lens portion 13 will be represented by H. Next, the processing procedure of the lens portion 13 will be explained with reference to FIG.
As shown in Figure a, a pilot hole 14 for burring is formed in the top plate 12 of the electrode body 11 by punching or the like. Next, the end surface 15 of this prepared hole 14 for burring
Then, as shown in FIG. 7B, a coining process is performed using a coining punch 17 having a chamfered part 16 to form a chamfered part 18. This coining process is performed on the end surface 1 of the pilot hole 14 for burring.
This serves to improve the burring hole expansion rate by removing the fine cracks occurring in the area 5 and also removing the work-hardened layer in this area.

Next, as shown in FIG.
Perform burring processing in step 9. This burring process is performed in multiple steps while gradually increasing the outside diameter of the burring punch by 10 to 15%.
As a result, the inner diameter of the burring is gradually expanded at a rate of 10 to 15%, but at this time, a tensile force in the circumferential direction is applied around the burring, and the thickness of the burring side wall 20 is increased to the size shown in FIG. 7a. It gradually decreases from the thickness _t0 , and is finally reduced to a thickness t, which is about 1/2 of the material thickness _t0 , as shown in FIG. 7d. This reduction in wall thickness is used to increase the burring height H. Furthermore, burring punch 1
In order to almost completely eliminate the deformation of the burring tip when removing 9, the final burring diameter D has an expansion ratio of 1.5% or less as an inner diameter ratio with respect to the burring diameter Dn in the immediately preceding burring process. It is set as follows.

In the above embodiments, an in-line type electrode has been described as the electron gun electrode, but it can be similarly applied to a delta type electrode.

As is clear from the above description, according to the present invention, a pilot hole for burring is formed in the top plate, and then the end face of the pilot hole for burring is chamfered, and then the main lens electrode is integrally formed by burring. By forming the lens part into one piece, it is possible to integrally mold a lens part with sufficient burring height for performance, simplifying the manufacturing process, and significantly improving assembly accuracy by improving both cylindricity and roundness. I can do it. It also has extremely significant effects in terms of performance and cost, increasing productivity by three times compared to conventional methods and reducing manufacturing costs by approximately one-third.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an example of the main lens electrode of a conventional integrated in-line electron gun, Fig. 2 is a vertical sectional view of Fig. 1, and Figs. 4 is an enlarged cross-sectional view showing the shape of the lens portion formed by the method shown in FIGS. 3a and 3b, and FIG. 5 is a vertical cross-sectional view showing the main lens electrode structure of a conventional integrated in-line electron gun. side view,
FIG. 6 is a longitudinal sectional view showing an example of an integrated in-line electron gun main lens electrode obtained by the method of the present invention;
FIGS. 7a to 7d are enlarged explanatory diagrams illustrating a method for processing a lens portion of an integrated in-line electron gun main lens electrode according to the present invention in order of steps. DESCRIPTION OF SYMBOLS 11... Electrode main body, 12... Top plate, 13... Lens part, 14... Prepared hole for burring, 16... Chamfered part,
17... Coining punch, 18... Chamfered part, 19
...burring punch.

Claims (1)

[Claims] 1. A pilot hole for burring is formed in the top plate, and then the end face of the pilot hole for burring is chamfered, and then a main lens electrode is integrally formed by burring. How to process the electrode part of an electron gun. 2. The method of processing an electrode portion of an electron gun according to claim 1, wherein the chamfering of the end face of the burring pilot hole is coining using a coining punch having a chamfer. 3. Processing of an electrode part of an electron gun according to claim 1, wherein the burring process consists of a plurality of steps, and the inner diameter of the burring in the final step is increased by 1.5% or less in terms of inner diameter ratio compared to the immediately preceding step. Method.