JPH011675A - Method for manufacturing fuel tanks for motorcycles - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a fuel tank mounted on a frame of a motorcycle.

(Prior Art) Since the fuel tank of a motorcycle is mounted on the frame in front of the driver's seat, it is necessary to have a smooth curved surface and a sharply curved curved surface for the sake of appearance and convenience of vehicle use. be. As a reminder, the outer surface of the tank should be designed bz
Generally, a mild steel plate with good elongation is used for the shell, and this is deep drawn to form an entirely curved shell, to which a separately formed bottom plate is welded.

In order to make it easy to install a fuel filler port on such a shell, we made a top surface piece with the fuel filler port formed in advance and left and right side pieces formed by deep drawing separately, and attached both pieces to the ceiling. A method for overlapping welding in the section is disclosed in Japanese Utility Model Publication No. 11831/1983.

(Problems to be Solved by the Invention) Even in motorcycles, the use of corrosion-resistant light alloys such as duralumin has become desirable from the standpoint of weight reduction and simplification of the painting process.

However, such materials have low extensibility, are dish-shaped, and cannot be deep drawn, so they cannot be used in fuel tanks of conventional structure for motorcycles.

Also, as in the above-mentioned Utility Model Publication No. 59-11831, if the top plate is divided by a flat ceiling and made into separate pieces, the fuel filler opening of the top plate can be easily removed. However, the side plate has a curved part with a small radius of curvature between the relatively flat ceiling part and the side part, and this curved part requires deep drawing. Furthermore, materials such as duralumin are difficult to weld, and it is extremely difficult to weld them without leaking fuel vapor.

(Problem? A precautionary measure to solve the problem) As a means to solve these problems, the first invention provides a fuel for a motorcycle in which a plate is curved to form a shell having an upper surface and left and right side surfaces. In the tank manufacturing method, the top plate and side plate made of releasable light alloy plates are formed separately, the edges of the two plates to be joined are butted, and a grooved fire-resistant backing is inserted from the outside of the tank. The tri feature is that the backing is brought into contact with the backing and welded from the inside, and the weld bead that occurs in the groove of the backing is scraped off after welding to give a smooth finish. In a method for manufacturing a fuel tank for a motorcycle, which forms a shell body with a side surface of Match the
The tank is welded from the inside and outside, and the weld bead 2 produced on the outside surface is scraped off after welding to give a smooth finish.

(Function) With the above means, in each invention, the curved portion with a small curvature is located at the end of the plate and can be easily formed. When welding both plates, in the first invention, welding can be performed without leaving any pores by extruding the molten metal into the groove of the heat-resistant long pad, and in the second invention, welding on both sides also achieves high airtightness. A welded structure is obtained.

(Implementation World 1) The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the shell of a fuel tank manufactured by the method of the present invention. 3m) to the welding line (
4).

(4) is welded together as a precaution, and the top plate (2)
K has an oil filler port (5) formed on the side plate +31, +3
) A bottom plate (not shown) is welded to the opening (6) formed at the lower end of the fuel tank to form a fuel tank.

Position 11 of this welding line (4) is located in the middle of a sharply curved Si curved part with a small radius of curvature, and at this position the plate f2),
By separating +31, the plate can be easily deformed during die molding. If an attempt is made to form a sharply curved part in the middle part far from the end of the plate using the conventional method, it will result in deep drawing, which cannot be done with materials that are difficult to form.

The position of the end (2m) and (3a) is line (a) or (b)
As shown in the figure, the position may be in contact with the curved part of a sharp curve. In this case, the end of the curved part is also a free end, so deep drawing is not possible, and even with difficult-to-form materials such as duralumin. Can be molded.

The top plate (2) and side plate (3) are fixed on a fire-resistant backing αG such as plaster, as shown in Figure '11g2.
Welded from the inside using IG or MIG welding. , J.A.
A groove αB along the welding line is formed in the pad αG, and slag and the like are pushed out into the groove, thereby forming a highly airtight welded part. After welding is completed, the beam shown in Fig. 3(a))'a
Scrape off 2 and smooth it as shown in (bl) to complete the shell.

When we compared both TIG and MIG methods for welding corrosion-resistant light alloys, it was found that MIG has less welding distortion, faster welding speed, and has no practical problem in terms of airtightness, but is slightly inferior to TIG. Therefore, TIG welding is preferred, but MIG welding is advantageous when welding is automated.

The top plate (2) and side plate (3) can also be formed by the method shown in FIG. Both plates (2+, +31 are held on a non-grooved lining u as shown in f & in the same figure, welded from the inside to form a bee PQ completely, then welded from the outside to form a bee Pμs, The bead 2 (to) on the outside of the welding diameter was scraped off to make it smooth.

Both TIG and MIG welding methods were used to weld the same type on both sides or different types on both sides, and a welded structure with sufficient airtightness even with h deviation was obtained.

Although the welding distortion is larger than that of the method shown in Fig. 2, it was found that a welded structure with higher airtightness can be obtained by using TIG welding at least on the l side. However, at welding speed A, MI
Excellent G welding and suitable for automatic welding.

(Effect of the invention) As described above, the invention has a structure in which the top plate and the side plate are divided in the middle of a curved part with a small radius of curvature or at a position in contact with the curved part. It is also easy to draw.

By using a grooved backing as a welding means to push out the slag to the outer surface and scrape off the extruded portion, a welded structure with an airtight and smooth surface can be obtained.

Further, by welding from both sides and scraping off the bead 2 on the outer surface, a welded structure having high airtightness and a smooth outer surface can be obtained.

As a result, a lightweight fuel tank with high corrosion resistance and airtightness can be made from the release molding material, and the vehicle can be made lighter and painting can be omitted or simplified.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a fuel tank shell manufactured by the method of the present invention, Fig. 8g2 is a longitudinal cross-sectional view showing one welding method,
Figure 3 (a) is a cross-sectional view of the welded part, the same figure (bl is a cross-sectional view after finishing, Figure 4 (al is a vertical cross-sectional view during internal welding in another welding method, and the same figure fbl is a double-sided welding) (2)...Top plate (3)...Side plate (2)
a), (3a)... End σG, (13... Fireproof backing 011-$ 02. C141
, C15...Welding bead Patent applicant Honda Motor Co., Ltd. Figure 1 Figure 2

Claims (2)

[Claims] (1) In a method for manufacturing a fuel tank for a motorcycle in which a shell is formed by curving a plate to form a shell having an upper surface and left and right side surfaces, the top plate and side plates made of a light alloy plate that is difficult to form are separated. The edges of both plates to be joined are butted together, a grooved fire-resistant backing is brought into contact with the outer surface of the tank and welded from the inside, and the weld bead that occurs in the groove of the backing is shaved off after welding. A method for manufacturing a fuel tank for a motorcycle, which is characterized in that it can be removed and finished smoothly. (2) In a method for manufacturing a fuel tank for a motorcycle, in which a shell is formed by curving a plate to form a shell having an upper surface and left and right side surfaces, the top plate and side plates made of a light alloy plate that are difficult to form are separated. A motorcycle characterized in that the ends of the two plates to be joined are butted together, welded from the inside and outside of the tank, and the weld bead formed on the outside surface side is scraped off after welding to give a smooth finish. Method for manufacturing fuel tanks for