JPH0253271B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a frame body for a two-wheeled vehicle, the frame of which is constituted by a pipe member, and a part of which has a bracket for supporting a rear suspension.

``Prior Art'' As shown in FIG. 5, a conventional frame body for a two-wheeled vehicle includes a bracket 4 for supporting one end of a rear suspension 3 at the rear end of a main pipe 2 extending rearward from a head pipe 1. It is known that a configuration with a . The bracket 4 is attached to the peripheral surface of the rear end of the main pipe 2 by welding, as shown in the figure.

In addition, the frame body includes the down tube 5, the head pipe 1, the main pipe 2,
The overall framework is composed of the lower pipe 6, front stay 7, center pipe 8, seat pipe 9, back pipe 10, etc., and the seat pipe 9 and back pipe 10 are all connected via connecting pins 9a and 10a. They are detachably connected and can be separated from each other. In the figure, reference numeral 11 indicates the rear fork of the rear wheel W.
2 designates links that support the other end of the rear suspension 3.

``Problems to be Solved by the Invention'' Incidentally, in such a frame body, stress due to various loads acts on the whole or partially, and therefore, it is required to have sufficient strength to withstand these stresses. In particular, the bracket 4 shown in Fig. 5 receives a strong load in the direction of arrow A since it supports the rear suspension 3, so the strength of the bracket 4 is affected as well as the strength of the bracket 4 itself. Sufficient measures are desired from the viewpoint of the mounting structure for the main pipe 2 and its strength. On the other hand, it goes without saying that consideration should be given to reducing the overall weight of the frame body and manufacturability.

However, in the case of conventional frame bodies,
Since the bracket 4 is attached to the main frame 2 by direct welding to a part of the circumferential surface of the main frame 2, the stress due to the above load acts concentratedly on a part of the circumferential surface. , it became necessary to increase the wall thickness of the entire main pipe in advance, and as a result, there was a problem that the weight of the frame body increased. In addition, since the main pipe 2 is usually made of a round pipe and has a curved circumferential surface, attaching the bracket only by welding to such a curved surface is not easy to manufacture and requires a high level of skill. Ta.

"Means for Solving the Problem" The present invention provides a frame body for a two-wheeled vehicle in which a bracket for supporting one end of the rear suspension is attached by welding to the rear end of the main pipe extending rearward from the head pipe. A caul plate covering the rear end surface of the main pipe was attached to the main pipe by welding, and the bracket was attached by welding to both the surface of the caul plate and the circumferential surface of the main pipe.

"Function" According to the above means, the backing plate that covers the rear end surface of the main pipe exhibits an effect of preventing deformation of the cross-sectional shape at the rear end of the main pipe, that is, a reinforcing effect. Further, the front surface of the backing plate can be used as a surface to which a part of the bracket is welded, and since the surface of the bracket is flat, it facilitates the welding work of the bracket.

``Example'' This example shows an example in which the seat pipe 9 is applied to a detachable so-called split type frame body, similar to the conventional example shown in FIG. 5. A side view of the whole is shown. In this embodiment, the parts basically common to those of the conventional example shown in FIG. 5 are given the same reference numerals to simplify the explanation thereof.

In the embodiment, as shown in detail in FIGS. 1 to 3, the main pipe 2 extending rearward from the head pipe 1 is provided with a backing plate 20 that covers the rear end surface of the main pipe 2. is attached by welding the fillet around the entire circumference. A bracket 30 for supporting one end of the rear suspension 3 is attached by welding to both the surface of the backing plate 20 and the circumferential surface of the main pipe 2, as shown. That is, bracket 30
As shown in FIG. 2, when viewed from the rear end side of the main pipe 2, it is formed in a channel shape having a pair of opposing side plate portions 31, 31, and these side plate portions 3
1 and 31 are formed with lower contact edges 31a, 31a that contact the surface of the backing plate 20, respectively, and upper contact edges 31b, 31b that contact the upper circumferential surface of the main pipe 2, respectively. , each of these abutting edges are fillet welded and attached.

Here, the rear end surface of the main pipe 2 has a shape that is inclined with respect to the axis of the main pipe 2 so that its outline forms an ellipse, and therefore the backing plate 20 also conforms to the outline of the rear end surface. It is shaped like an elliptical plate. Further, near the rear end surface of the main pipe 2, a cylindrical member 22 is attached extending in the left-right direction of the frame body and forming a bolt hole for detachably attaching the seat pipe 9 with a bolt 21. ing. A part of the outer circumferential surface of this cylindrical member 22 is exposed so as to slightly protrude from the rear end surface of the main pipe 2. Therefore, the backing plate 20 has an arc-shaped cross section corresponding to the exposed part. A curved portion 20a is formed. The inner surface of this curved portion 20a is in contact with the exposed portion, thereby causing the cylindrical member 2
2 is pressed down by a backing plate 20. The thickness of the patch plate 20 is as follows:
In order to provide the main frame 2 with a reinforcing effect, it is preferable that the main frame 2 be thicker than the main frame 2.

According to the configuration of the above embodiment, the main pipe 2 is connected from the rear suspension 3 via the bracket 30.
The load acting on the peripheral surface of the main pipe 2 and
Because the stress is distributed between the backing plate 20 and the backing plate 20, the stress does not concentrate on a part of the circumferential surface of the main pipe 2 as in the conventional case, and the main pipe 2 maintains its cross-sectional shape by the backing plate 20. The structure is reinforced with sufficient strength. Therefore,
The wall thickness of the main pipe 2 can also be made thinner to achieve weight reduction. Furthermore, by attaching the caul plate 20, its surface can be used as a surface for welding a part of the bracket 30, and since the surface of the bracket 20 is flat,
Welding of the bracket 20 can be easily carried out without requiring special skill. Also, a cylindrical member 22 for attaching the seat pipe 9
Since the seat pipe 9 is pressed down from the outside by the backing plate 20, the strength of the attachment portion of the seat pipe 9 is also improved.

"Effects of the Invention" In the present invention, a backing plate that covers the rear end surface of the main pipe is welded to the main pipe, and a bracket for supporting the rear suspension is attached to the surface of the backing plate and the circumferential surface of the main pipe. Because it is attached by welding to both sides, the load acting on the main pipe through the bracket is dispersed, eliminating stress concentration.Furthermore, the main pipe itself is effectively reinforced by the patch plate. It is no longer necessary to increase the wall thickness of the bracket in advance, and therefore the weight of the frame body can be reduced by that amount.In addition, by providing the patch plate 20, the surface can be used as a mounting surface for the bracket. In addition to being usable, since the surface of the backing plate 20 is flat, it has excellent effects such as facilitating the welding of the bracket and improving productivity.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is an enlarged side view of the portion indicated by the arrow in FIG. 4, FIG. FIG. 4 is an overall side view of the frame body, and FIG. 5 is an overall side view of a conventional frame body. 1...Head pipe, 2...Main pipe, 3
...Rear suspension, 20...Painting plate, 30
...Bracket, 31...Side plate portion, 31a...Lower abutting edge, 31b...Upper abutting edge.

Claims (1)

[Claims] 1. In a frame body for a two-wheeled vehicle, in which a bracket for supporting one end of the rear suspension is attached by welding to the rear end of a main pipe extending rearward from the head pipe, the rear end surface of the main pipe is attached to the main pipe. A frame body for a two-wheeled vehicle, characterized in that a covering plate is attached by welding, and the bracket is attached by welding to both the surface of the cover plate and the circumferential surface of a main pipe.