JPH07115174B2 - Autoby frame welding structure - Google Patents

Description

The present invention relates to a motorcycle frame welding structure.

[Conventional technology and its problems]

Recent motorcycles are required to have higher performance.
Therefore, the output of the engine has been increased and the frame has been made lighter. For this reason, the frame may be made of light alloy. Compared to iron, light alloys are more difficult to weld and the welding cost is higher. To reduce the number of welding points and welding work, as shown in Fig. 1, the head metal fitting 1 and the left and right center metal fittings 2 are made of light alloy by casting or forging, and projections 3 are formed on the ends of both metal fittings 1 and 2. Is provided, the ends of the upper pipe 4, the lower pipe 5, and the rear pipe 6 of the light alloy pipe are inserted, and the joint 7 is welded. Normally, the abutment 7 is provided with a circumference of about 4 mm as shown in FIG. 5, and the abutment 7 is MIG welded. This welding is difficult to automate,
The manufacturing cost is high, and the wide weld beads are visible, so the appearance is not good. See JP-A-59-223581.

[Object of the Invention]

This invention uses MIG welding and T
The purpose of the present invention is to obtain a motorcycle frame welding structure in which IG welding is performed in half and the number of welding steps can be reduced and the cost can be automated and inexpensive, and the welding beads can be finished with a narrow width and good appearance.

[Structure of Invention]

 Hereinafter, the present invention will be described with reference to FIGS. 1 to 4.

The structure of the frame is the same as that described in the prior art,
As shown in FIG. 1, a head metal fitting 1 made of cast or forged light alloy, an upper pipe 4, a lower pipe 5, and a rear pipe 6 made of a light alloy pipe on a protrusion 3 provided at the end of the left and right center metal fittings 2.
The end portion of is inserted, and the inserted portion is welded and joined. The present invention, therefore, uses the protrusion 3 of the metal fitting 1 or 2.
In addition, as shown in FIG. 2, the abutment 7 at the place where the pipes 4, 5 and 6 are inserted and welded is slanted on the upper and lower surfaces to form a small outer gap 8 (about 1 mm) and a large inner gap 9 ( (About 4 mm)
To Further, as shown in FIGS. 3 and 4, a step is provided on the upper and lower surfaces to form a small gap 8 on the outside and a large gap 9 on the inside. Then, the small gap 8 on the outside of the abutment 7 is TIG welded, and the large gap 9 on the inside of the abutment 7 is MIG welded.
Weld.

[Operation of the invention]

Insert the ends of pipes 4, 5 and 6 into the protrusions 3 of the metal fittings 1 and 2,
When welding, the small gap 8 part outside the gap 7 is
Automatic TIG welding by robotization can be easily done from the outside, and automation can reduce costs. Then, the large gap 9 portion inside the abutment 7 is manually MIG welded. With the large gap 9, the welding depth is deep and sufficient welding strength can be maintained. In appearance, a small gap 8 outside the gap 7.
The weld bead of the part will be visible and the appearance will be good.

〔The invention's effect〕

As described above, the present invention provides a motorcycle frame in which the ends of the upper pipe, the lower pipe, and the rear pipe are inserted into the projections provided at the ends of the cast or forged head metal fittings and the center metal fittings and welded. , When the pipe end is inserted into the protrusion, the gap of the abutment is made smaller on the outside and larger on the inside, MIG welding is performed on the large gap on the inside, and TIG welding is performed on the small gap on the outside. Etc. can be automated and cost can be reduced,
The weld beads are also narrow and have a good appearance. And the inner MIG
The portion to be welded has a deep welding depth and sufficient welding strength. Even if the weld bead is wide, it is difficult to see inside, so there is no appearance problem.

[Brief description of drawings]

FIG. 1 is a perspective view of the entire frame, FIG. 2 is an enlarged perspective view of a welded portion showing an embodiment of the present invention, FIGS. 3 and 4 show another embodiment of the present invention, and FIG. Is an enlarged perspective view of a welded portion, FIG. 4 is a sectional view taken along the arrow AA in FIG. 3, and FIG. 5 is a vertical sectional view of a welded portion showing a conventional example. 1 ... Head fitting, 2 ... Center fitting, 3 ... Protrusion,
4 ... upper pipe, 5 ... lower pipe, 6 ... rear pipe, 7
…… A gap, 8 …… small gap, 9 …… large gap.

Claims (1)

[Claims] 1. A motorcycle frame in which the ends of an upper pipe, a lower pipe, and a rear pipe are inserted into and welded to projections provided at the ends of a cast or forged head metal fitting and a center metal fitting, and the pipe ends are joined to the projections. The frame welding structure for motorcycles is characterized in that when the is inserted, the gap at the abutment is made smaller on the outer side and larger on the inner side, the large gap on the inner side is MIG welded, and the smaller gap on the outer side is TIG welded.