JPS6120629A - Burring method - Google Patents

Abstract

PURPOSE:To form with high accuracy a cylindrical part whose tip has been inclined, by using a straight punch and a punch formed by changing the shape of the tip R part, and burring by two processes. CONSTITUTION:A prepared hole 4 having the prescribed hole pitch and inside diameter (d) is formed on a top plate 2. A burring punch 10 having an R part 10a at the tip and a burring die 11 are offset to that which has a large burring height so as to have an interval of about 0.2mm. to the side wall of the prepared hole 4 and working is executed. In this way, that which has a larger burring height is formed to H3. Subsequently, working accompanied by drawing with ironing is executed by using a burring punch 20 which has enlarged an R part 20a of the tip by that which has a larger burring height and has formed the outside wall of a side wall part 20b so as to be smaller than the outside diameter of the R part 20a, and has formed the outside diameter of a side wall 20c to the same as the R part 20a. In this way, a burring cylindrical part 3A for satisfying prescribed heights H1, H2 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a burring method for forming a burring cylindrical portion having an inclined tip.

[Background of the invention]

Burring is used to process the electrodes of electron guns used in color cathode ray tubes. The main lens electrode of an integrated in-line electron gun will be explained below as an example.

As shown in FIG. 1, this main lens electrode is formed by burring the top plate 2ζ of the electrode main body 1, which has an elongated cylindrical shape.
The cylindrical portions 3A, 3B, and 3C are formed close to each other in an in-line manner, and the tips of the cylindrical portions 3A, 3C on both sides are inclined so as to sufficiently play the role of the main lens electrode.

Now, set the height of the inner parts of the cylindrical parts 3A and 3C on both sides to Hl.
, the height of the outer part is H2, then Hl needs to be larger or smaller than H2. The figure shows the case of HI<H2.

Conventionally, in order to obtain the necessary cylindrical parts 3A, 3B, and 3C,
After drawing into an oval shape, it is formed by the steps shown in FIG. Now, for convenience of explanation, only the formation of the left side cylindrical portion 3A will be explained.

First, as shown in FIG. 2(a), pilot holes 4 are formed in the top plate 2 at a predetermined pitch and inner diameter d. Next, using a press mold as shown in FIG. Figure 2 (as shown in bl), the predetermined burring height H,
A burring cylindrical portion 3A that satisfies H is formed. Here, the burring punch 5 shown in FIG. 3 is arranged eccentrically with respect to the hole of the burring die 6 in the direction where the burring height is larger. Note that 7 indicates a lower die knockout, and 8 indicates a spring.

However, in this conventional burring method, the burring cylindrical portions 38 to 3C are formed in one burring process, so the burring punch 5 is used during the burring process.
The stress acting on the side wall portion 5b is greater when the burring height is larger than when the burring height is smaller, and the burring punch 5 is deformed toward the smaller burring height, resulting in a predetermined burring height H,
, H2 and the hole pitch of the burring cylindrical parts 3A to 3C cannot be determined.

[Purpose of the invention]

An object of the present invention is to provide a burring processing method that can form the burring height and the hole pitch of the burring cylindrical portion with high precision.

[Summary of the invention]

In order to achieve the above object, the present invention divides the burring process into two steps. In the first step, a straight burring punch with an R section at the tip is used, and the burring punch and burring die are adjusted to the burring height. Offset to the larger side and process only the larger burring height,
In the next second step, the outer diameter of the side wall portion on the side that has an R portion at the tip and is machined with a larger burring height is set to the R portion.
Using a burring punch, the outer diameter of the side wall on the side where the burring height is smaller is the same as the outer diameter of the R section. It is characterized by processing both sides together.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4, 5, and 6. Note that the same members and portions as in FIGS. 1 and 2 will be described with the same reference numerals.

After drawing into a long cylindrical shape, a pilot hole 4 is first formed at the apex 2 with a predetermined hole pitch and inner diameter d, as shown in Figure 4). Next, as shown in FIG. 4B, the pilot hole 4 is left in the smaller burring height, and only the larger burring height is machined to a height H3t smaller than the predetermined height H2. This processing is performed using a press die as shown in FIG.

As shown in FIG. 5, a straight burring punch 10 having an R portion 10a at the tip and a burring die 11 are placed at a distance of about 0.2 cm between the side wall of the prepared hole 4 and the side wall 10b of the burring punch 10. By offset processing toward the larger burring height so that the burring height is larger, only the larger burring height is formed to the height H3. In addition, by avoiding a gap between the side wall 10b of the burring punch 10 and the side wall 11a of the burring die 11 (by rubbing, deformation of the burring punch 10 during burring is suppressed by the side wall 11a of the burring die 11. 12 is a lower mold knockout, and 13 is a spring.

Next, as shown in FIG. 4fcl, both the larger and smaller burring heights are subjected to burring with rubbing to form a burring cylindrical portion 3A that satisfies predetermined burring heights Hl and Hl. do.

This processing is performed using a press die shown in FIG.

As shown in FIG. 6, the burring punch 2o has a tip t.
The one with the eight portions 20a and the larger burring height,
The outer diameter of the side wall portion 20b is formed to be smaller than the outer diameter of the eight portion 20a by forming the eight portion 20a larger than the circular arc, and in the case where the burring height is smaller, the outer diameter of the side wall portion 20c is made larger than the eight portion 20a.
It is formed to have the same outer diameter. In addition, 21 is a burring die, 22 is a lower die knockout, and 23 is a spring. Therefore, the side wall portion 20b does not contact the burring side wall 3a, and the side wall 20c does not contact the burring side wall 3b, so deformation of the burring punch 20 toward the smaller burring height is suppressed, and the burring height Hl, H2 and hole pitch accuracy are reduced. will improve.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to suppress the deformation of the burring punch during burring of a burring cylindrical part with an inclined tip, so that the burring height and the pitch of multiple holes can be suppressed. It is possible to improve the accuracy of

[Brief explanation of drawings]

Figure 1 shows the main lens electrode of the integrated in-line electron gun, fa) is a plan view, (b) is a sectional view, and Figure 2 fa) (b) is a cross-sectional view.
) is a process explanatory diagram showing the conventional burring method, Part 3
The figure is an enlarged sectional view of the main part of the press die used for the burring process shown in Fig. 2, and FIGS. 4(a) and 4(b) IC) are process explanatory diagrams showing one embodiment of the burring process method according to the present invention. , FIG. 5 is an enlarged cross-sectional view of the main part of the press mold used in the step of FIG. 4(b), and FIG. 6 is an enlarged cross-sectional view of the main part of the press mold used in the step of FIG. 4 fc). 2... Top plate, 4... Pilot hole, 3A, 3B,
3C...burring cylindrical part, 1o, 2o...
Burring punch, 10a, 20 a-R section,
i. b, 20b, 20c...side wall portion, 11.21 ・
...Burring die. Figure 1 (0) (1:+) Figure 2 (0) (b) Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] In a burring method in which a pilot hole is formed in the top plate and the pilot hole is burred to form a burring cylindrical portion with an inclined tip, the burring process is divided into two steps, and in the first step, the tip is burred. Using a straight burring punch with an R section, offset the burring punch and burring die to the side with the larger burring height to process only the one with the larger burring height.
In the process, the outer diameter of the side wall part on the side that has an R part at the tip and the side where the larger burring height is processed is smaller than the outer diameter of the R part, and the side wall part on the side where the burring height is smaller is processed. A burring processing method characterized in that both the larger and smaller burring heights are processed using a burring punch whose outer diameter is the same as the outer diameter of the R section.