JPH02197323A - V-bending method for composite type laminated steel plate - Google Patents

Abstract

PURPOSE:To execute V-bending without generating a gull wing-like shape defect by pressing a composite type laminated steel plate by a punch from the upper part, and also, giving opposed pressure from a pad through a coil spring provided in the lower die. CONSTITUTION:In a space of the lower die body 8, a pad 9 and a coil spring 10 are set. On the horizontal surface of the upper part of this pad 9, a high damping composite steel plate 4 formed by placing viscoelastic resin between and laminating a steel plate is placed. Subsequently, a pump 2 is placed and pressed against the upper face of said steel plate 4 from the upper part. As a result, the coil spring 10 is compressed and the pad 9 moves to the lower part, and while giving opposed pressure from the lower part, the steel plate 4 is bent to a V-shape. In that case, a load of the steel plate 4 to the die 8 part is very small, and a gull wing phenomenon based on stress concentration is not generated. In this case, it is suitable that Rockwell hardness of the coil spring 10 is 42-45, and a spring constant is 3.0-21.0kgf/mm and 1.50-7.0kgf/mm in the case when a V-bending angle is <=90 deg., and >=90 deg., respectively.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for performing 7-bending of a composite laminated steel plate in which a viscoelastic resin is sandwiched between steel plates using a hydraulic press brake or the like. The present invention provides a method for bending a laminated steel plate without causing shape defects.

(Conventional technology) Traditionally, bending of steel plates using hydraulic press brakes, etc. has been widely used for steel furniture, wall materials, doors, etc., and since it is a relatively simple process, there are no problems with the processed shape. There were almost no problems.

However, recently, with the application of composite laminated steel sheets sandwiched with viscoelastic resin to the processing, it has become clear that defects in the processed shape are likely to occur, which was not a problem with single sheets in the past, and improvements are needed. ing.

(Problems to be Solved by the Invention) When the conventional bending method is applied to a composite laminated steel plate in which a viscoelastic resin is sandwiched between steel plates as a material for bending, as shown in Figure 1. As shown, the buckling occurs at the flange of the shoulder of the lower mold, resulting in a seagull-wing shape when viewed in cross section. (below,
The shape caused by this phenomenon is called a “seagull” shape)
In addition, in order to eliminate this drawback, for example, after performing various preliminary processing on the composite laminated steel plate that is the object to be subjected to V-bending, Efforts are being made to improve this, or to change the thickness and yield strength of the front and back steel plates.

However, with these methods, there is a limit to improving the shear adhesion between the outer steel plates in terms of allocation performance, and changing the thickness and material of the front and back steel plates may cause distortion in the laminate due to the thermal history during manufacturing. It is possible that this may occur. On the other hand, the method of deleting a specific layer, the method of cutting grooves and the method of drilling holes,
The disadvantage is that the composite type vibration damping steel plate must be pre-processed in advance, and furthermore, by providing notches or peeling off parts of the composite type laminated steel plate itself,
■There was also the problem that the strength of the bent portion was significantly reduced.

(Means for solving the problem) In order to solve these conventional drawbacks, as a result of intensive study, we found that when V-bending a composite laminated steel plate, in a bending die that applies spring pressure, The problem was solved by using a spring with hardness equal to the width of the spring, placing a pad on the top of the spring, then pressing the top surface of the composite laminated steel plate with a punch and bending while restraining the deformation of the material at the top of the pad part. The aim is to

To explain more specifically with reference to FIGS. 2 and 3,
When using a V-bending mold consisting of the lower mold body 8, punch 2, pad 9, and coil spring 10, a space for inserting the pad and coil spring is provided in the lower mold body 8, and then the butt 9 and coil spring 10 are set. Then, a composite laminated steel plate 4 is placed on the horizontal surface of the upper part of the vat and bent.

When the punch 2 and the upper surface of the composite vibration-damping steel plate are pressed together in a processing device having such a configuration, the coil spring 10 is compressed and at the same time the bat 9 moves downward and bends into a figure 7 shape while receiving bending stress.

At this time, the angle of the composite vibration-damping steel plate 40 is determined by the compression of the punch tip and the coil spring 10, so the load of the composite laminated steel plate on the mold part of the mold is extremely small, and therefore no stress concentration occurs here. The "seagull" phenomenon will no longer occur.

(Example) Examples will be described in detail below.

Example 1 A composite damping steel plate consisting of a viscoelastic resin layer with a core thickness of 0°05fi and laminated thin galvanized steel plates (thickness: 0.27 tm) on both sides was used. As shown in Figure 1, the shear strength between the outer steel plates is 120 to 150, and the hardness of the spring material is 42 to 45 within the range of /cIiI.
(Hue), spring constant 3.05~5.46 (kgf
90° press bending was performed under the conditions of 1 m), and the ``gull'' phenomenon was evaluated according to the following criteria.

○ There is no "seagull" phenomenon at all △ "seagull" phenomenon is not understood × "seagull" phenomenon is noticeable Within the range of 5.46kgf/mu, “
The "Kamome" phenomenon was not observed at all.

In the comparative example, the hardness of the spring material was the same as above, the spring constant value was set to 1.87 kirf/111, and when the spring constant was bent at 90 degrees, the angle became 90 degrees or more, and the spring constant was reversed to 13
．． When the angle was increased to 12 kgf/**, the angle became less than 90', and the "seagull" phenomenon was observed in both cases.

Table 2 shows that the shear strength between the outer skin steel plates has been further improved.
200-220kg/-, hardness (HRC) 42-45
The results of 90° bending are shown by expanding the range of the spring constant.

Spring constant is 2698~7.0k due to increased shear strength
gf/m, no "seagull" phenomenon was observed, and the moldability was good.

The reason for this is that by improving the shear strength, V
This seems to be due to the fact that the springback angle during bending becomes smaller, so the flange at the shoulder of the lower mold is not subjected to enough load to cause the "seagull" phenomenon.

Comparative example with spring constant of 2.08 and 9.76kgf 7w
In this case, even if the shear strength was increased, a "seagull" phenomenon was observed due to the spring constant.

Example 2 Using the composite damping steel plate shown in Example 1, the shear strength between the outer skin steel plates was 120 to 150 kg/c as shown in Table 3.
Spring constant 4.91~9.83kgf/ within the range of fA
A 60° bending process was performed under crane conditions, and the "seagull" phenomenon was evaluated using the criteria shown in Example 1.

In the case of 606 bending in Table 3, the spring constant is 4.91 to 9.83.
Within the range of kgf/+u, no "gull" phenomenon was observed at all.

In the comparative example, the value of spring constant and 3.1.2 kirf/mI
When Jl is decreased, the angle becomes 606 or more, and conversely, when the spring constant is increased to 1.3.02 kgf/*n, the angle becomes 606 or less, and the "seagull" phenomenon was observed under both conditions.

Table 4 shows 2
The test results of 60° bending at 00 to 220 kir/- are shown.

Due to the increase in shear strength, the spring constant value also increased, and no "seagull" phenomenon was observed.

In the comparative example, even if the shear strength was increased, the "seagull" phenomenon was observed at spring constants other than those of the example, regardless of the hardness.

Table 1 Shear strength 120/150kg/c- (90°
Bending) Table 2 Shear strength of 200 to 220 kg/c+ll (90
6 bending) Table 3 Shear strength 120 to 150 kg/cIa (60°
Bending) Table 4 For shear strength of 200 to 220 kg/elf (60°
Bending) (Effects of the Invention) According to the present invention, when the composite vibration damping steel plate is always bent into a figure 7 shape, the angle is adjusted by compression of the coil spring via the pad, so it is less expensive than the conventional bending method. Since the load of the composite damping steel plate on the shoulder of the mold is small, no concentrated load is generated here, which has the effect of preventing the "gull" phenomenon.

[Brief explanation of the drawing]

Figure 1 shows the "seagull" phenomenon that occurs in a composite laminated steel plate when the conventional V-bending method for steel plates is applied, and Figures 2 and 3 show the V-bending process using the coil spring according to the present invention. An example of performing the bending method will be shown. 1... Lower mold, 2... Punch, 3... Steel plate, 4...
...Composite vibration damping steel plate, 8...Lower mold body, 9...Pad, 10...Coil spring.

Claims (1)

[Scope of Claims] 1) When V-bending a composite laminated steel plate sandwiching a viscoelastic resin, counter pressure is applied from a pad that comes into contact with the laminated steel plate to be processed through a coil spring provided in a lower mold. A method for V-bending a composite laminated steel plate, characterized in that buckling deformation of a lower mold shoulder is prevented by: (2) In claim 1, the coil spring has a Rockwell hardness of 42 to 45, a spring constant of 3.0 to 21.0 kgf/mm when the V-bending angle is 90° or less, and 1.0 kgf/mm when the V-bending angle is 90° or more. A method for V-bending a composite laminated steel plate, characterized in that the bending angle is 50 to 7.0 kgf/mm.