JPS59179284A - Production of fuel tank for automobile - Google Patents

Abstract

PURPOSE:To perform quickly adequate welding irrespectively of a shape and to improve working efficiency in production of a fuel tank for an automobile by bending and butting the flange parts of two container members formed of metallic sheets having intricate shapes and subjecting the same to copy welding by a laser beam. CONSTITUTION:A fuel tank 1 for an automobile has an extremely intricate shape and is formed by bending and butting first two flange parts 11a, 12a by means of rollers 2a, 2b. A long focus laser beam 3 is then irradiated to the butt parts in a way as to trace said parts by which the butt parts are welded. Since the butt parts are easily copy-welded irrespectively of the shape of the tank and the shape of the butt parts, the working efficiency is improved with stabler quality.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a fuel tank for an automobile.

In recent years, in automobiles, a space dedicated to the fuel tank has been created to expand the passenger compartment for the purpose of improving comfort, or to install various devices near the fuel tank neck position for the purpose of purifying exhaust gas and improving performance. We cannot secure enough. Moreover, since it is desired to increase the volume of the tank, the outer shape of the tank becomes complicated due to the use of irregularly shaped empty spaces between the devices.

By the way, the first method for manufacturing fuel tanks for automobiles is
As shown in the figure, the flanges 11a and 12a formed at the openings of the upper half 11 and lower half 12 of the container-shaped tank are brought into contact with each other, and both 7 flanges i1a and 12a are joined by continuous electric resistance welding. There is. Both 7 lunges 11a, 12a
After tightening the abutment V, connect these from above and below to the electrode wheel 2a.
, 21), and while applying electricity between the wheels 2a and 2b, the wheels 2a and 2b are moved around the seven lunges 11a and 12a and continuously welded, thereby constructing the fuel tank 1 as a closed container.

However, in this method, the seven lunges 11a, 12a
If there is a part with a large curvature, the electrode wheels 2a, 2b cannot be aligned, and the container wall needs to have a simple shape to prevent contact with the wheels 2a, 2b.
There are major restrictions on the shape of a combustion tank. If the wheel diameter is made smaller, the above problem will be overcome to some extent, but with small diameter wheels, the frequency of replacement will be more frequent and the work efficiency will be worse.

In view of the above-mentioned problems, it is an object of the present invention to provide a method for efficiently and accurately manufacturing a fuel tank having a complicated shape, particularly a method for joining the upper and lower halves.

That is, the manufacturing method of the present invention is characterized by abutting the flanges of a pair of metal container-like members each having seven flanges formed in the opening, and joining these flanges by laser welding.

Embodiments of the present invention will be described below with reference to FIG.

The upper half 11 and lower half 12 of the fuel tank 1 are made of metal plates, and are formed in the shape of a container, with flanges 11a and 12a formed at the frontage, respectively. Then, the flanges Ila and 12a of the half part 11 and the lower half part 12 are brought into contact with each other, and the outer peripheral edge of the flange 12a is bent so as to wrap around the 7 flange 11a, thereby integrating the two parts. The laser beam 3 is irradiated along the flange bent portions of the integrated upper and lower halves 11 and 12, and the entire assembly is welded to form a sealed container. For this laser welding, a well-known raping device that focuses the rake beam 3 with a condensing lens and irradiates the focused beam can be used.

Therefore, according to the present invention, since laser welding is non-contact welding and the laser beam 3 can be irradiated intensively to an extremely minute area, the flanges 11a, 12a
Even parts with large curvature can be easily welded, and slight irregularities on the container wall do not pose an obstacle to laser welding. Therefore, a fuel tank with a complicated shape can be manufactured.

In addition, in conventional contact welding using electrode wheels, the wheels wear out and often need to be replaced, but this problem does not occur. Furthermore, laser welding allows the energy density to be concentrated, so there is no heat effect on areas other than the welded area. is small, and there is little welding distortion.

As described above, the method for manufacturing a #1 fuel tank of the present invention allows fuel tanks of complex shapes to be manufactured efficiently and accurately.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the conventional manufacturing method, and FIG. 2 is a sectional view showing the manufacturing method of the present invention. 1... Fuel tank 11.12... Tank upper and lower halves 11a, 1
2a...7 lunge 3...laser beam

Claims (1)

[Claims] 1. A method of manufacturing a fuel tank for an automobile, which comprises forming a flange at the frontage of a metal plate, abutting the flanges of a pair of container-shaped members, and joining these seven flanges by laser welding.