JPH0458385B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for treating the edges of a board having a laminated plywood, and particularly to a method for treating the edges of a board having a laminated plywood, and in particular, a method for treating the edges of a board having a laminated plywood. The present invention relates to an edge treatment method for joining an edge of plywood and an edge of a metal plate.

(Prior art) Conventionally, for automobile bodies, etc., laminated plywood, which is made by laminating thin metal plates on both surfaces of a synthetic resin intermediate layer, has been used to reduce weight and absorb vibrations. I came.

When assembling the panel structure by using the above laminated plywood as the outer panel of a panel structure such as an automobile door or using a metal plate as the inner panel and joining the ends of the laminated plywood and the metal plate, the structure shown in FIG. a
When the end portion 102A of the laminated plywood 102 is folded back and hemmed as shown in FIG. 3B, and the laminated plywood 102 and the metal plate 103 are joined by spot welding as shown in FIG. 3B, the following problem occurs.

The thickness of the metal plate 103 is approximately 1.0 mm, which is very thin, so the bent portion 103 of the laminated plywood 102
The curvature of the bent portion 104 becomes so large that the thin metal plate on the outer surface of the bent portion 104 breaks, and the heat during welding is transmitted to the outer surface of the laminated plywood 102 through the metal plate 103, causing the thin metal plate on the outer surface to break. There are problems such as deformation of the board and deterioration of the appearance of the outer panel.

Therefore, for example, in Japanese Utility Model Application No. 57-125321,
The end of one thin metal plate of the laminated plywood is made to protrude beyond the end surface of the other thin metal plate, and the protruding portion is folded back and hemmed to weld the end of the laminated plywood and the metal plate. A bonding edge treatment technique is described.

However, the edge processing technology described in the above publication has a structure in which only one thin metal plate of the laminated plywood is folded back and hemmed, which is unfavorable in terms of the strength of the joint, and the overall thickness of the joint. Because of this, the thin metal plates on the outer side of the laminated plywood will be deformed due to thermal distortion during welding, deteriorating the appearance, and the two thin metal plates of the laminated plywood will be processed so that the end faces of the two thin metal plates are shifted rather than aligned. There are problems such as difficulties in equipment and process to do so.

(Object of the invention) The present invention was made in view of the above problems, and
An object of the present invention is to provide a method for treating the edges of a plate material including a laminated plywood, which can prevent tearing of the thin metal plate at the bent portion of the laminated plywood and deformation of the thin metal plate on the outer surface side of the laminated plywood.

(Structure of the Invention) A method for treating the edges of a board having a laminated plywood according to the present invention is to treat the ends of a laminated plywood as an outer panel formed by laminating thin metal plates on both surfaces of a synthetic resin intermediate layer to the inner side. Bend it into a flange shape, bend the end of the metal plate as an inner panel to the inner side with a curvature smaller than the curvature of the folded part of the laminated plywood, overlap the metal plate on the inner surface of the laminated plywood, and fold the edge of the laminated plywood near the edge. and the vicinity of the edge of the metal plate are welded together, and the end of the laminated plywood and the end of the metal plate are folded back onto the inner surface of the metal plate and hemmed.

(Effects of the Invention) In the method for treating the edges of a plate material equipped with a laminated plywood according to the present invention, the end of the laminated plywood is bent inward into a flange shape, and the end of the metal plate is bent to the curvature of the bent portion of the laminated plywood. It bends toward the inside with a smaller curvature than the curvature, welds and joins the edge of the laminated plywood and the edge of the metal plate, then folds it back and hems it. Since the distance to the unbent outer edge of the plywood becomes longer, deformation due to thermal distortion of the thin metal plate at the outer edge of the laminated plywood can be prevented.

When the parts near the edges are welded together and then folded back, the curvature of the bent part of the laminated plywood and the curvature of the end of the metal plate are set to be approximately equal, and the ends of the two are overlapped. If the laminated plywood is combined and folded back, there is a risk that the tensile stress at the bent portion of the laminated plywood will become excessive and cause the thin metal plate on the outer surface to tear. Since the bending curvature of the metal plate is set small, it is possible to reliably prevent tensile stress other than bending stress from acting on the bent part of the laminated plywood, and the end of the laminated plywood is folded back with two metal plates in between. The hemming bending curvature also becomes smaller and the bending stress is alleviated.

In this way, it is possible to reliably prevent the thin metal plate on the outer surface side of the bent portion of the laminated plywood from being torn or distorted.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

For example, a thin steel plate 2b having a thickness of approximately 0.1 to 0.4 mm is laminated on both surfaces of a synthetic resin intermediate layer 2a as an outer panel of a panel structure 1 consisting of an outer panel and an inner panel, such as a car door. Using the laminated plywood 2 and a steel plate 3 with a thickness of approximately 0.8 to 1.2 mm as the inner panel, the ends of the laminated plywood 2 and the ends of the steel plate 3 are joined through the following steps to form the panel. Structure 1 is assembled.

First, as shown in FIG. 1a, the laminated plywood 2
The end portion 2A of the steel plate 3 is bent into a flange shape by approximately 90° toward the inner side by press working, and the end portion 3A of the steel plate 3 is
The bent part 4 of the laminated plywood 2 is formed by pressing A.
The steel plate 3 is stacked on the inner surface of the laminated plywood 2 with a curvature (1/R) smaller than the curvature (1/r) of the laminated plywood 2, and the steel plate 3 is The edge portion 3B is overlapped with the edge portion 3B, and the edge portion 3C of the steel plate 3 is overlapped with the outer end 2C of the laminated plywood 2.

In this state, the bent portion 4 of the laminated plywood 2
As shown in the figure, a gap 5 which is relatively large is provided between the inner surface of the inner surface of the adjacent portion and the outer surface of the end portion 3A of the steel plate 3, and the length of the steel plate in the gap 5 is longer than the length of the girth along the laminated plywood 2 in this gap 5. The girth length along line 3 is larger by a predetermined amount.

Next, as shown in FIG.
The fixed side electrode 6b is applied to the inner surface of B and heated, and after the synthetic resin intermediate layer 2a of the laminated plywood 2 is softened, electricity is applied between both electrodes 6a and 6b to close the area near both edges 2.
B and 3B are welded together.

Finally, as shown in FIG.
and are folded back onto the inner surface of the steel plate 3 and hemmed.

At this time, the laminated plywood 2 is bent at the bending part 4, and the steel plate 3 is bent at the part of the laminated plywood 2 closest to the bending part 4.

Here, the relationship between the bending radius r of the bent portion 4 of the laminated plywood 2 and the curved bending radius R of the end portion 3A of the steel plate 3 can be theoretically determined as follows.

That is, the thickness of the steel plate 3 is t1, the total thickness of the laminated plywood 2 is t2, the distance between the center of curvature of hemming bending and the inner end of the welded joint 7 is B, as shown in FIG. As shown in FIG. 1b, if the distance between the centers of curvature is A, the following equation is obtained.

A=(R-r)+(t1+t2)/2 (1) 2B+t1×π/2=R×π/2 (2) 2B+(t1+t2/2)×π =2A+r×π/2 (3) Above (1) )(2) By eliminating A and B from equations (3), the following equation is obtained.

(R-r)= (t1+t2)×(π-2)/(4-π) (4) In other words, the radius of curvature r of the bent part 4 of the laminated plywood 2 and the radius of the curved curve of the end 3A of the steel plate 3 If R is set so that it satisfies the above formula (4), the laminated plywood 2 will be bent without any tension acting on the laminated plywood 2 when it is folded and hemmed as shown in Figure 1 c. Become.

In the above-mentioned edge processing method, since the edge vicinity portion 2B of the laminated plywood 2 and the edge vicinity portion 3B of the steel plate 3 are welded together before hemming, the outer edge of the laminated plywood 2 is separated from the welded portion during welding. The outer end 2C will not be deformed by welding heat due to the longer distance to the outer end 2C.

In addition, although both edge portions 2B and 3B are welded together and then folded back and hemmed, the above R>
If R and r are set to values that satisfy equation (4), no tension will be applied to the laminated plywood 2 during folding and hemming.

Furthermore, since the end portion 3A of the steel plate 3 is also folded back and sandwiched between the end portions 2A and 2C of the laminated plywood 2, the hemming bending curvature of the laminated plywood 2 is also reduced, and no adverse effects of bending stress appear.

It goes without saying that the end portion 3A of the steel plate 3 may be bent to have a polygonal cross section as shown in FIG.

[Brief explanation of drawings]

1 and 2 of the drawings show an embodiment of the present invention, and FIGS. 1 a to 1 c show the respective steps of joining the ends of the laminated plywood and the ends of the steel plate and processing the ends. FIG. 2 is a vertical cross-sectional view of the end of a steel plate according to a modified example, and FIGS. 3 a and b are longitudinal cross-sectional views of a portion obtained by hemming a laminated plywood to a metal plate, respectively, according to the prior art. and FIG. 9 is a vertical cross-sectional view showing a state in which the laminated plywood is being hemmed and welded to a metal plate. 2... Laminated plywood, 2a... Synthetic resin intermediate layer, 2b
...Thin steel plate, 2A...end portion, 2B...near edge portion, 3...
Steel plate, 3A... end, 3B... edge vicinity.

Claims (1)

[Scope of Claims] 1. An end of a laminated plywood serving as an outer panel formed by laminating thin metal plates on both surfaces of a synthetic resin intermediate layer is bent inward into a flange shape, and an end of the metal plate serving as an inner panel. Bend it toward the inner surface with a curvature smaller than the curvature of the bent part of the laminated plywood, overlap the metal plate on the inner surface of the laminated plywood, and weld and join the near edge of the laminated plywood and the near edge of the metal plate. A method for treating the edges of a plate material including laminated plywood, characterized by folding the edges of the plywood and the edges of the metal plate onto the inner surface of the metal plate and hemming them.