JPS6322893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for bending the end portion of a corrugated curved material such as a metal cover.

BACKGROUND TECHNOLOGY When bending and forming an end portion of a corrugated curved material A, the forming is performed using a lower punch 2, an upper punch 1, and an upper die 3.

Problems to be Solved by the Invention When the bent portion 4 is made straight as shown in FIGS. 1 and 2, the relationship between the wavy line lengths l ₁ and l ₂ and the bent line lengths l' ₁ and l' ₂ is
l ₁ >l' ₁ and l ₂ >l' ₂ , wrinkles were generated in the contracted portion 5 of the bent portion 4, and cracks were generated in the extended portion 6.

Further, as shown in FIG. 4, when l ₁ = l' ₁ and l ₂ = l' ₂ , wrinkles due to excess thickness were eliminated, but folding wrinkles that occur at the start of bending were generated in areas where the curvature suddenly changes.

As shown in FIG. 6, the lower die punch 2 and the upper die 3 have the same shape, and the corrugated curved material A
It is thought that the bending wrinkles were formed because the bending direction of the sudden curvature change part indicated by P is greatly different from that of the adjacent part.

In FIG. 6, a cross section taken along line - is shown in FIG. 7, and a cross section taken along line - is shown in FIG.

Both cross sections shown in FIGS. 7 and 8 are in a state immediately before the start of bending, and the entire corrugated curved material A, including both cross sections, is simultaneously bent by the lowering of the upper die 3.

For this reason, as shown in FIG. 9, the upper die 3 was gently missed at the P portion, but this time the bending timing of this portion was delayed compared to the adjacent portion, resulting in creases.

The present invention has been made in view of the above circumstances, and its purpose is to prevent the occurrence of bending wrinkles by gradually progressing the bending from the sudden curvature change part P of the corrugated curved material A to the adjacent part. An object of the present invention is to provide a method for bending a corrugated curved material.

Means and Effects for Solving the Problems The present invention provides a structure in which a corrugated curved material A is bent and formed by a lower punch 2, an upper punch 1, and an upper die 3. Wavy line length l ₁ , l ₂
and the bending line lengths l' ₁ and l' ₂ of the bent portion 4 are made substantially equal, and the timing of bending the abruptly changing curvature portion P of the corrugated curved material A is made earlier than that of the adjacent portion.

Embodiment Hereinafter, one embodiment of the present invention will be described in FIGS. 10 to 12.
This will be explained with reference to the figures.

There is a sudden change part 1 on the left and right of the peak part 7 of the lower die punch 2.
1 and 12 are formed.

Further, advance bending portions 9 and 10 are formed on the left and right sides of the valley portion 8 of the upper die 3. These preceding bent portions 9 and 10 overlap the sudden change portions 11 and 12 when the valley portion 8 matches the peak portion 7.

In Figure 10, the cross section along the XI-XI line is
1, and a cross section taken along line XII--XII is shown in FIG. 12.

The cross section shown in FIGS. 11 and 12 shows the state in which the bending of the wave-shaped curved material A has progressed due to the lowering of the upper die 3, and the wave shape at the sudden change parts 11 and 12 (see FIG. 12) Curved material A is bent in other parts (11th
It can be seen that the bending occurs earlier than the bending of the corrugated curved material A at (see figure).

Thus, the corrugated curved material A is formed using the upper die punch 1, the lower die punch 2, and the upper die 3.

At this time, as shown in FIG. 12, the waveform curved material A is bent and formed by the advance bending parts 9 and 10 of the upper die 3 before other parts.

In this way, the timing of bending the sudden curvature change part P of the corrugated curved material A is earlier than that of the adjacent part, but the bending gradually progresses from the sudden curvature change part P to the adjacent part, so folding wrinkles are eliminated.

The present invention is as described above, and when the wavy curved material A is bent and formed by the lower punch 2, the upper punch 1, and the upper die 3, the wavy line lengths l ₁ and l ₂ of the wavy curved material A are
The bending line lengths l' ₁ and l' ₂ of the bent portion 4 are made to be approximately equal, and the timing of bending the sudden curvature change part P of the corrugated curved material A is made earlier than the adjacent part, so that the sudden curvature change part Since the bending gradually progresses from P to the adjacent portion, it is possible to eliminate the occurrence of bending wrinkles.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a corrugated curved material made by the conventional bending method, Fig. 2 is a plan view with the same part omitted, Fig. 3 is an explanatory diagram of the configuration of the mold device, and Fig. 4 is a corrugated curved material. 5 is a plan view with the same part omitted, FIG. 6 is an explanatory diagram of the shapes of the upper die and lower punch when the upper die and lower punch have the same shape, and FIG.
The figure is a cross-sectional view along the line of Fig. 6, and Fig. 8 is a cross-sectional view along the line of Fig. 6.
The figure is a cross-sectional view taken along the line, Figure 9 is an explanatory diagram of the shape of the upper die and lower punch when the abrupt curvature change part of the upper die is smoothed, and Figure 10 is the upper die used in the method of the present invention. An explanatory diagram of the shape of the die and lower die punch, Fig. 11 is a cross-sectional view along the line XI-XI in Fig. 10, Fig. 12
The figure is a sectional view taken along the line XII--XII in FIG. 10. 1 is an upper die punch, 2 is a lower die punch, 3 is an upper die, and A is a corrugated curved material.

Claims (1)

[Claims] 1 Cut the corrugated curved material A into the lower die punch 2 and the upper die punch 1.
When bending and forming with the upper die 3, the wavy line lengths _l1 , _l2 of the corrugated curved material A and the bending line lengths l' ₁ ,
A method for bending a corrugated curved material, characterized in that the curved curved material A is made to have approximately the same value as l' ₂ , and the timing of bending the sudden curvature change part P of the corrugated curved material A is earlier than that of the adjacent part.