JPH06135365A - Frame construction of motorcycle - Google Patents

Abstract

PURPOSE:To provide the frame construction of a motorcycle, by which a connecting work can be simplified and the production efficiency can be improved. CONSTITUTION:A motorcycle has such a frame construction that a pair of right and left main pipes 2 are extended backward while increasing the lateral width from right and left side faces of a cylindrical head pipe 1 having bearing parts 1a, 1b at the top and the bottom thereof and the joint area between the main pipes and the head pipe 2 are reinforced by a gusset 4. In the frame construction of the motorcycle, the gusset 4 has its side piece parts 4b extended from the central part welded to the rear side face of the head pipe 1 right and left obliquely backward while expanding in the lateral width, and the right and left paired main pipes 2 are pressed to both side piece parts 4b from the outside and connected thereto by welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame structure for a motorcycle, in which a main pipe branches left and right and a main pipe extends rearward.

[0002]

2. Description of the Related Art Many motorcycles have this kind of frame structure, and a conventional general example near the head pipe is shown in FIG.

That is, a pair of left and right main pipes 02 extends rearward from the left and right side surfaces of the upper portion of a cylindrical head pipe 01 having upper and lower bearing portions 01a and 01b while expanding in the width direction. Similarly, a pair of left and right down pipes 03 extends downward from the left and right side surfaces of the lower portion of the head pipe 01, and a reinforcing pipe 05 is interposed between the cross pipe 04 and the down pipe 03 which are installed between the pair of left and right main pipes 02. It is equipped.

The tips of the main pipe 02 and the down pipe 03 are abutted and welded to the head pipe 01 to join them, but the head pipe 01 rotatably supports a front fork that rotatably supports the front wheel. An excessive bending moment is applied to the upper and lower joints of the head pipe 01 by the load generated between the ground and the ground.

Therefore, the head pipe 01 and the main pipe
An upper gusset 06 and an under gusset 07 are welded to the joint portion with 02 and the joint portion with the head pipe 01 and the down pipe 03 for reinforcement, respectively. Further, the center gusset 08 may be welded over the head pipe 01, the down pipe 03, and the reinforcing pipe 05. There is an example in which the frame member mounting portion is integrally cast on the head pipe (Japanese Utility Model Laid-Open No. 61-15686), but the gusset portion becomes large.

[0006]

As described above, in the conventional general frame structure, the main pipe 02 and the down pipe 03 are first joined to the head pipe 01, and then the upper gusset 0 is connected.
6. Since the under gusset 07 and the center gusset 08 are welded, a joining jig is required for each process, and the joining process is decentralized such that the number of attachments and detachments to the jig increases. As a result, production efficiency is poor, leading to higher costs and increased jig equipment investment.

The present invention has been made in view of the above points, and an object of the present invention is to provide a frame structure of a motorcycle which can easily perform a connecting work with a small number of connecting jigs.

[0008]

In order to achieve the above object, the present invention provides a pair of left and right main pipes extending in the left-right width direction from the left and right side surfaces of a cylindrical head pipe having upper and lower bearing portions. In a motorcycle having a frame structure that extends rearward and a joint portion with the head pipe is reinforced by a gusset, the gusset extends from the center portion welded to the rear side surface of the head pipe to the left and right diagonally rearward while spreading in the left-right width direction. The motorcycle has a frame structure in which one piece extends and the left and right main pipes are applied to the both side pieces from the outside and welded together.

Since the main pipe is applied from outside to be welded to the head pipe where the gusset is joined at its central part and assembled, the main pipe can be positioned by the left and right side pieces of the gusset. The number of jigs is small and the connecting work is simplified and the production efficiency can be improved.

[0010]

EXAMPLE An example of the present invention shown in FIGS. 2 to 9 will be described below.

2 and 3 are a side view and a plan view showing the entire frame structure of the motorcycle of this embodiment. A pair of left and right main pipes 2 from the upper and left side surfaces of a cylindrical head pipe 1 having upper and lower bearing portions 1a and 1b.
Spreads in the left-right width direction and extends backward and slightly downward. Further, a pair of left and right down pipes 3 extend obliquely downward from the lower left and right side surfaces of the head pipe 1.

The above-mentioned main pipe 2 and down pipe 3
A gusset 4 integrally press-molded is welded to the joint portion of the head pipe 1 for reinforcement. Cross pipes 5 and 6 are installed between the left and right main pipes 2, and a reinforcing pipe 7 is interposed between the front cross pipe 5 and the left and right down pipes 3.

A rear end of the main pipe 2 is continuously connected to a center frame 8 vertically downward and a seat rail 9 is connected rearward, and a back stay 10 for reinforcing the seat rail 9 is provided. Is interposed below the center frame 8.

In detail, the shape of the gusset 4 used in the joint structure around the head pipe 1 in the vehicle body frame structure is as shown in FIG. That is, the gusset 4 has a central concave portion 4a having a circumferential concave surface formed in the center corresponding to the rear side surface of the head pipe 1, and the left and right side pieces 4b extend rearward from the central portion 4a while expanding in the left-right width direction. In addition, the upper and lower edges of the left and right side pieces 4b are connected to each other to form a fan-shaped upper piece 4c, and the lower end edges are connected to have a lower piece 4d. As a whole, the respective pieces 4b, 4c and 4d are radially formed from the central recess 4a. It is formed to be extended, and the whole is integrally formed by press working.

The left and right side pieces 4b are symmetrical and have a semicylindrical recess 4 into which the front end of the main pipe 2 is placed.
e, a semi-cylindrical convex portion 4f that abuts the front end portion of the down pipe 3 is formed in the lower portion to form a smooth wave shape as a whole. A reinforcing plate 20 is installed between the left and right side pieces 4b.

The procedure of connecting the head pipe around the gusset 4 will be described. First, as shown in FIG. 5, the central recess 4a of the gusset 4 is applied to the rear side surface of the head pipe 1 by welding. FIG. 6 and FIG. 7 are views showing a state in which the gusset 4 is connected to the head pipe 1 to be in a small assembled state.

The main pipe 2 and the down pipe 3 are applied to the head pipe structure assembled in this way from the outside of the gusset 4. The front end of the main pipe 2 is slantedly flattened on the inside and applied to the concave portion 4e of the side piece 4b of the gusset 4, and the front end is abutted on the head pipe 1 so that the flattened part and a part of the circumferential surface are gusseted. The concave portions 4e are brought into contact with each other to be positioned, and are welded to each other to be joined (see FIGS. 8 and 9).

On the other hand, the front end portion of the down pipe 3 is fixedly attached with a metal plate 3a which is obliquely cut on the inner side and is curved at the cut end to form a part of a cylinder. The metal plate 3a is provided with a convex portion 4f of the gusset 4. Welding and joining from the outside.

After the main pipe 2 and the down pipe 3 are welded and joined to the head pipe 1 in which the gusset 4 has been assembled in a small size as described above, the frame body is removed from the jig, and the joining work around the head pipe 1 is completed. .

On the left and right side pieces 4b of the gusset 4, there are concave portions 4e and convex portions 4f for setting the main pipe 2 and the down pipe 3.
Is provided, the positions of the main pipe 2 and the down pipe 3 are determined, the gusset 4 itself serves as a jig, and the joining jig itself can be simplified.

Conventionally, the upper gusset, the under gusset and the center gusset were welded to a plurality of gussets, but since the gussets are integrated in this embodiment,
The number of joint work steps is reduced, and the main pipe 2 and the down pipe 3 are applied from the outside to the place where the gusset 4 is assembled to the head pipe 1 and welded. The whole structure can be simplified, the production efficiency can be improved, and the cost can be reduced. In addition, there are few jigs, and capital investment is minimal.

In the gusset 4 of this embodiment, the portion to which the down pipe 3 is welded is the convex portion 4f, but conversely, as the concave portion, the front end of the down pipe 3 is abutted against the head pipe 1 and is similar to the main pipe 2. It may be welded to.

In the above embodiment, the gusset 4 is integrally formed by pressing, but it may be integrally formed by casting, and an example thereof is shown in FIGS. 10 to 12 and described.

The head pipe 30 has a structure in which bearings 30a and 30b are provided on the upper and lower sides and a cylindrical portion 30c is connected to each other similarly to the above-described embodiment, while a gusset which is a cast product.
31 is a left-right symmetrical shape, the central part along the head pipe 30
Left and right side pieces 31b extending backward from 31a in the left-right width direction
And the left and right side pieces 31b are connected to each other at their upper end edges to have a fan-shaped upper piece 31c and lower end edges are connected to each other to have a lower piece 31d. As a whole, each piece 31b, 31c, 31d is provided from the central portion 31a. It is formed to extend substantially radially.

The left and right side pieces 31b are composed of two upper and lower recesses 31e and 31f obtained by dividing a cylinder into halves, and a central portion 31a between the base ends of both recesses 31e and 31f has a U-shaped cross section. Open end
31 g contacts the cylindrical portion 30 c of the head pipe 30 and is welded to it. Others The central portion 31a of the gusset 31 is the head pipe 30.
The upper piece 31c and the lower piece 31 are separated from each other and fan-shaped in the upper and lower parts.
The base ends 31h and 31i of d are vertical bearing portions 30 of the head pipe 30.
It abuts on a and 30b and is welded.

In this way, the gusset 31 is welded and integrally joined to the head pipe 30 at the upper and lower base ends 30a and 30b and the central opening end 31g, and the main pipe and the down pipe are vertically recessed 31e and 31f. To the head pipe 30 and welded.

It is also possible to use the gusset 31 integrally manufactured by casting as described above, and the coupling work can be simplified and the production efficiency can be improved as in the above-mentioned embodiment.

[0028]

According to the present invention, since an integral gusset having side pieces extending from the center to the left and right is welded to the head pipe and positioned on the side pieces, the main pipe is applied and welded together. The number of jigs is small, the connecting work is simplified, the production efficiency can be improved, the cost can be reduced, and the capital investment can be reduced.

[Brief description of drawings]

FIG. 1 is a side view showing a structure around a conventional head pipe.

FIG. 2 is a side view showing a vehicle body frame structure of a motorcycle according to an embodiment of the present invention.

FIG. 3 is a plan view of the same.

FIG. 4 is a perspective view of a gusset of this embodiment.

FIG. 5 is a side view immediately before connecting the gusset to the head pipe.

FIG. 6 is a side view showing a state in which a gusset is welded to a head pipe.

FIG. 7 is a view on arrow VII in FIG.

FIG. 8 is a side view showing a state in which a main pipe and a down pipe are welded to a head pipe to which a gusset is joined.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a side view showing a state in which a gusset is connected to a head pipe of another embodiment.

11 is a view on arrow IX in FIG.

12 is a view on arrow XII in FIG.

[Explanation of symbols]

1 ... Head pipe, 2 ... Main pipe, 3 ... Down pipe, 4 ... Gusset, 5, 6 ... Cross pipe, 7 ... Reinforcement pipe, 8 ... Center frame, 9 ... Seat rail, 10 ...
Back stay 20… Reinforcement plate, 30… Head pipe, 31… Gusset.

Claims (1)

[Claims] 1. A frame in which a pair of left and right main pipes extends rearward from the left and right side surfaces of a cylindrical head pipe having upper and lower bearing portions while expanding in the left-right width direction, and a joint portion with the head pipe is reinforced by a gusset. In a motorcycle having a structure, the gusset has a side piece extending from the central portion welded to the rear side surface of the head pipe to the left and right diagonally rearward in the left-right width direction, and a pair of left and right main portions on both side portions respectively. A frame structure for motorcycles in which the pipes are applied from the outside and welded together.