JPS60231525A - Bending method of laminated steel plate - Google Patents

Abstract

PURPOSE:To prevent plate shifting and mouth opening by pulling and elongating the other plate in the stage of bending a laminated steel plate sandwiching a resin layer toward one plate side. CONSTITUTION:The laminated steel plate 3 is sandwiched between a punch 1 and a movable die 6. Bending of one end of the plate 3 by a stationary die 2 is executed by ascending of the punch 1 and retreating of the die 6. Resistance parts 8 which apply resistance to the steel plate 5 in contact with the forming surface 7 of the die 2 are provided to said surface by forming projections, etc. and therefore the shifting of the plate 5 is controlled and only the steel plate 4 is permitted to shift. The plate 5 is therefore pulled by the parts 8 and is elongated in the bending direction until bending is completed. The pressing force acts also toward the inside in the thickness direction thereof. The lengths at the front ends of the flanges are thus unified and the mouth opening is prevented by the above-mentioned method.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for bending a laminated steel plate consisting of two steel plates with a resin layer sandwiched between them, and particularly relates to a method for bending a laminated steel plate, which is formed by sandwiching a resin layer between two steel plates, and particularly relates to a method for bending a laminated steel plate, in which a resin layer is sandwiched between two steel plates. Concerning what to prevent.

[Technical background of the invention and its problems 1 Laminated steel plates, which are made of two steel plates with a resin layer sandwiched between them, have come to be widely used in automobile parts, such as oil pans, instead of single steel plates. Ta.

This is because the intermediate resin layer absorbs and attenuates vibrations from the internal combustion engine, thereby reducing the generation of noise due to vibrations.

Incidentally, the ends of many automobile parts, such as oil pans, are flanged in order to be attached to other parts. FIG. 4 shows a mold bending device which is one means of this flange forming, and as the bunch 1 rises, a rising wall surface along the side wall of the die 2 is formed on one end of the blank 3. In particular, when the blank plate 3 is a laminated steel plate, a unique problem occurs that does not occur when using a single steel plate. This is the gap between the boards and the opening.

As shown in FIGS. 5 and 6, the plate deviation a is caused by the difference in line length that occurs because the intermediate resin layer has almost no resistance to the sliding of both sets of plates 4 and 5, and the opening b is Bending part R
This is due to the difference in springback due to the difference in the radius of curvature of the two plates.

When this sheet misalignment or opening occurs, the strength of the bent portion where these occur will decrease and rust will occur due to water intrusion.

Therefore, when bending laminated steel plates, it is necessary to take various measures on the bent parts by secondary processing such as welding or sealing with a sealant in order to prevent strength loss or rust due to water intrusion. There is.

However, these countermeasures not only complicate the work but also lack reliability.

[Objective of the Invention] The object of the present invention is to prevent sheet deviation and displacement in the bending section due to the structure of laminated steel sheets based on the above-mentioned conventional bending technology.
In view of the problem of gap opening, by pulling one steel plate in the bending direction during bending, the above defects can be removed and plate slippage and gap gap can be prevented without taking various measures through secondary processing.
The object of the present invention is to provide an excellent method for bending laminated steel plates, which simplifies the work and allows the amount of sheet deviation to be controlled arbitrarily.

[Summary of the Invention] The present invention, which achieves the above object, takes advantage of the property that in laminated steel plates, the intermediate resin layer has almost no resistance to sliding between both sets of plates. When bending in the lateral direction, the other steel plate is stretched in the bending direction, thereby eliminating misalignment and opening between one steel plate and the other steel plate.

[Embodiments of the Invention] Examples of the present invention will be described below based on FIGS. 1 and 4. In this embodiment, a damping steel plate formed with a viscous resin layer interposed between the steel plates will be described as an example.

As shown in Fig. 1, the damping steel plate 3 consists of two steel plates 4°5,
A viscous resin layer is interposed in the middle to perform vibration damping molding. Bending means for flange forming the damping steel plate 3 include die bending, bending, roll forming, etc., and a die bending apparatus is exemplified here.

That is, as shown in FIGS. 1 and 4, the mold bending device includes a punch 1 that can be raised and lowered, and a movable punch that moves backward with a damping steel plate 3 sandwiched between it as the punch 1 rises. The die 6 is installed flush with and adjacent to the movable die 6 before retraction, and one end of the damping steel plate 3 is made to follow the forming surface 7 by raising the punch 1 by -L and retracting the movable die 6. It consists of a fixed die 2 for bending and forming on an upright wall surface.

On the molding surface 7 of the fixed die 2, a resistance portion 8 is provided on the steel plate 5 in contact with the molding surface 7 to provide resistance in the bending direction of the damping steel plate 3. In the example shown in FIG. 1, this resistance section 8 is shown as having a plurality of protrusions in the bending direction, which is simple and reliable, but other resistance means such as an uneven section may be used.

Now, in the above configuration, if one end of the damping steel plate 3 is placed on the movable die 6 and the fixed die 2, and the punch 1 is prevented from rising, the rise of the punch 1 and the retreat of the movable die 6 are prevented. Accompanying this, the vibration-damping steel plate 3 is pressed, and one end thereof sequentially moves from the tip 9 hl of the fixed die 2 to the forming surface 7 and starts bending. Of one end of the damping steel plate 3 that has moved to the forming surface 7 , the steel plate 5 in the opposite direction to the bending direction is held by a protrusion serving as a resistance section 8 provided on the forming surface 7 to prevent deviation in the direction opposite to the bending direction. , only the steel plate 4 on the bending direction side is allowed to shift in the direction opposite to the bending direction, and this state continues until the final stage of forming.

By the way, in the period up to the end of forming, there is a springback difference in the damping steel plate 3 due to the line length difference between the two assembly plates 4.5 due to slippage and the difference in the radius of curvature, so the length of the flange tip is In order to align the edges and eliminate the opening, it is necessary to stretch the steel plate 5 in the opposite direction, which is shorter than the steel plate 4 in the bending direction, and press it inward in the thickness direction. , which requires a large amount of force in the bending direction.

However, until the final stage of forming when the bending process is completed, the steel plate 5 in the six directions opposite to the bending direction is gripped by the protrusions serving as the resistance portions 8 provided on the forming surface 7, so that the steel plate 5 is given resistance in the bending direction and is pulled. , it is stretched in the bending direction, and a pressing force is applied inward in the thickness direction. Therefore, the plate displacement portion is extended, the lengths of the flange tips are made equal, and opening is prevented. The height D of the protrusion required to bite into the steel plate 5 and pull it in the bending direction during this bending process is approximately 0.05.
~0.3 mm is suitable. The thickness of one steel plate is approximately 0.8 mm. Because of this height, marks of the protrusions will clearly remain on the outer surface of the flange after processing.

FIG. 2 shows a modification of the embodiment shown in FIG.
The difference from the drawing is that a cutout 10 is provided at the base of the bunch 1 located at the tip of the flange, and as a result, an advantage is obtained that the tightness of the tip of the flange is further increased by the constraint of the cutout 10.

FIG. 3 also shows a modification of the embodiment shown in FIG.
The difference from the diagram is that the tips of the flanges are not only aligned, but the steel plate 5 on the opposite side to the bending direction is further stretched to be longer than the steel plate 4 on the bending direction, and as a result, a slight sheet misalignment occurs naturally. It is possible to form a plate deviation difference C that is larger than the difference,
An advantage is obtained that the sealing performance can be improved by applying a sufficient amount of the sealant 11 here.

[Effects of the Invention 1 In summary, according to the present invention, the following excellent effects are exhibited.

(1) When bending a laminated steel plate in the direction of one plate side,
I stretched the other plate by pulling it in the bending direction, so
It is possible to effectively prevent the occurrence of sheet deviation and opening during the forming process, and there is no need to take various countermeasures against these by secondary processing, and the work can be simplified.

(2) By controlling the tensile force, it is possible to arbitrarily control the sheet displacement in the bending section.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view of a bending apparatus implementing the method of the present invention, and FIG. 2 is an enlarged sectional view showing another embodiment.
Fig. 3 is a sectional view of a bending section when the steel plate in the opposite direction is shifted longer than the steel plate in the bending direction by the method of the present invention, and Fig. 4 is a bending device common to the method of the present invention and the conventional method. Fig. 5 is an enlarged sectional view of a bending device implementing the conventional method, and Fig. 6 is a cross-section of the bending part to explain the conventional drawbacks of sheet slippage and opening. It is a diagram. In the figure, 3 is a damping steel plate that is an example of a laminated steel plate, 4 is one steel plate, and 5 is the other steel plate. Patent Applicant: Isubo Jidosha Co., Ltd. Tokyo Radiator Manufacturing Co., Ltd. Representative Patent Attorney Nobuo Kinuya Engraving of the drawing (no changes to the content) Procedure Negotiations - 4 (method) August 20, 1980 Commissioner of the Japan Patent Office Shiga Gakuden 1, Indication of the case Japanese Patent Application No. 59-86695 Bow 2, Title of the invention Method for bending laminated steel plates 3, Relationship with the person making the amendment 1'1 Patent applicant (017) Isuzu Motors Co., Ltd. 1 Name 4, Agent Postal Kakuyumi 105 Atago 1-6-7, Atago 1-6-7, Minato-ku, Tokyo 111 Lawyers Building 5, Amendment Order [1 attached July 559, 31r, l (Shipping Port) 8, Attachment i!
! Catalog of items (1) 1 copy of drawings

Claims (1)

[Claims] A laminated steel plate consisting of two steel plates with a resin layer sandwiched between them, characterized in that when one of the laminated steel plates is bent in the side direction, the other plate is stretched in the bending direction. Bending method.