JPS6067284A - Frame structure of motorcycle - 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] The present invention relates to a frame structure for a motorcycle.

Conventionally, as shown in Fig. 1, the frame structure of a motorcycle includes a down tube 2 that hangs downward from a head pipe l and then extends rearward, and a main tube 18 that extends rearward from the head pipe 1. Y. Formed by bending seven square pipes, and reinforcing this part at the one-sided connection part 4, which is a continuous part of the down knee 12 and the main tube 8 in a curved form. There is a known structure in which a gusset plate 5 which also serves as a gusset plate 5 is welded and a vibond bearing 7 of a rear fork (not shown) is provided on this gusset plate 1-5.

By the way, in a frame with a stiff structure, if the radius of curvature of the above-mentioned one-face connection part 4 can be made as small as possible, the degree of freedom in design will improve, and the entire frame will have a truss structure. Although this is preferable from the viewpoint of the strength of the frame, the minimum radius of curvature of the one-face connection part 4, etc. is almost determined by the size of the square pipe to be bent and its processing technology, so if the radius of curvature is smaller than that, Not only is it extremely difficult to bend the frame with a radius, but it also reduces the strength of the frame itself.

Furthermore, as shown in FIG. 2, the welding points of the gusset plate 4 to the one-plane connection part 4 and the welding points of the pivot bearing 7 to the stiff gusset plate 4 overlap, making welding work difficult. is 7
This has the disadvantage that it appears on the outside of the electric body (on the outside of the electric body) and spoils the appearance.

The present invention was made in consideration of the above-mentioned ignition, and
It is possible to reduce the radius of curvature of the curved connection part without reducing the strength of the 7-frame frame, increasing the degree of freedom in design.Also, welding is easy and the welding points are concentrated on the inside of the vehicle body to improve the appearance. It is possible to increase the direction Lχ, making it much lighter and lighter.
The purpose is to provide a frame structure for motorcycles that also contributes to cost reduction, etc., and its features include 5 box-shaped connections consisting of an inner mold and an outer mold that are preformed into the required shape. The rear ends of the down tube and the main tube are connected to each other by a member, and a rear fork pivot portion is provided at the connecting portion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on an embodiment shown in the drawings.

Figure 3 shows the frame structure of the automatic 2@tun according to the present invention.
Like the one shown in the figure, it has a double cradle type, and includes a head pipe 11 and a down tube 1 that hangs downward from the head pipe 11 and then extends rearward.
2, a main knee 118 extending rearward and lower from the head pipe 11, a connecting member 14 connecting the lower end of the main tube 18 and the rear end of the down tube 12.ct), and a connecting member 14 extending rearwardly and upwardly from the connecting member 14. MIt is made up of a backstay 15 and a seat pipe 16 which extends rearward from the main tube 18 and is welded to the backstay L5. Both are square shaped.

The connecting member 14&''L, as shown in Figures t1 to 7, is two members whose cross section has a rectangular shape and is previously formed into a required shape by processing means such as press molding or casting. That is, the inner mold I7 and the outer mold 18 are welded together, and the whole is formed into a hollow box shape.

The edge of the outer mold 18 that becomes the OJ joint with the inner mold 17 is the inner mold 1.
7 rung part 1.8 a expanded outward by the wall thickness of 7
The two are welded such that the edge of the inner mold 17 is fitted inside the core J flange portion 18a. Connecting member 14'J (one end r upper end) &i, main tube 1
Fitting port 14 into which the 8θ lower end is inserted and welded
a, the other end (lower end) is also a low joint 14 for making the rear end of the down tube 12 a base and welding it in place, b
(see Fig. 3 (DJ)) In addition, the outer mold 18 is provided with a contour so that the main tube 13 and the down tube 12 are continuous when viewed from the outside, and the strength of the entire connecting member is improved. A raised part tab is formed that contributes to the reinforcement of the crescent-shaped profile other than this raised part 18b.
Pivot bearing 1 penetrates from this part toward inner mold 17
9 is welded. In addition, the part of the outer peripheral part of the connecting member 14 that is welded to one end of the backstay 15 cv has a KIL rating of 1Rσ) as shown in Figure 5' (A).
A portion of the seventh rung portion 18a is removed and abutted against the inner mold 17 to form a flat surface. In addition, in fJS, Fig. 7, the reference numeral 204 indicates the protrusion tB provided on the connecting member 14.
The main step attached to the embedded nut 22 and the protruding piece 23 of the part 21, and the trace-on step attached to the backstay 15 are shown at 24, respectively.

In the above-mentioned 7-frame structure, instead of bending the down pipe 12 and the main tube 18 into a single square pipe to form a curved connection part, as in the conventional case,
An inner mold 17 formed in advance into a required shape corresponding to the curved connection portion by processing means such as press molding or casting.
and a box-shaped connecting member [4] consisting of the outer mold 18 constitutes a portion corresponding to a curved connection part, so when molding the connecting member 14, the curvature of the connecting member 14 can be made as small as necessary. In addition, the degree of freedom in design is improved without causing a decrease in strength7, and the curvature of the connecting member 14I7) can be made small in this way, so that the strength of the frame connection can be reduced. Moreover, it becomes easy to obtain a preferable truss structure as close as possible.

The connecting member 14 is made up of a vertically divided inner mold 17 and an outer mold 18, and seven rungs 18a are provided at the edge of the outer mold 18.
'Y-forming lever (7) 7 rungs 1. Since the structure is such that the edge of the inner mold 17 is fitted onto the inside of f3a and the two are welded together, the welding points are concentrated on the inside of the car body and do not appear on the outside, which improves the appearance accordingly. do. In addition, since the gusset part for installing the pivot bearing 19 of a rear fork etc. is integrally formed by the inner mold 17 and a part of the outer mold 1B, the gusset plate is welded and fixed to this as in the conventional case. L) Compared to JK, stress concentration at the welding margin edge can be eliminated, and welding is easier. Roughly speaking, connecting member 14 constituting a curved connection part is formed into a hollow box shape consisting of an inner mold 17 and an outer mold 18, and the square pipe bending part is removed, so the entire part is transposed. and cost reduction.

In addition, in the above embodiment, an example was explained in which a square pipe was used as the frame material, but the present invention is applicable only to square pipes and can also be applied to round pipes. be able to. In the case of 1,000 σ, each part of the connecting member may be formed to match the round pipe.

As explained above, according to the present invention, the rear ends of the down tube and the main tube σ are connected by the box fJjjct) connecting member, which is made of an inner mold and an outer mold formed in a required shape in advance, and the connecting member Because of the structure in which the pivot part of the rear 7 oak is provided, it is possible to reduce the radius of curvature of the curved connection part and improve the degree of freedom in design, without reducing the strength of the 7 frame. In addition, welding is easy, and the welding points 711 can be concentrated on the inside of the vehicle body, improving the appearance.This also contributes to reducing costs for several companies, etc.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the conventional frame structure 7, Figure 2 is Ge
Cross-sectional view along the tth v4υ■-■ curve, Figures 3 to S [
1 shows an embodiment of the present invention, Fig. 3 is a side view showing the frame structure, Fig. ψ is a side view of the connecting member, and Fig. 3 fA) is taken along line A-A of Fig. φ. Cross-sectional view, @3 Figure fB)
is a cross-sectional view taken along the line B-B in Figure 1, and Figure 3 (cross-sectional view taken along the line O-a in Figure 014, Figure 5 CD) is the Hiro FA.
It is an arrow diagram of I7-D. 11... Head pipe, 12... Down tube, 18... Main tube, ■4
......Connecting member, 17...Inner mold, 18.
...Outer mold, 19...Pivot bearing. Figure 4

Claims (1)

[Claims] A pre-required shape for a motorcycle in which the rear fork pivot portion is located at least in a portion where a pull-down tube that hangs downward from the head pipe and then extends rearward and a main tube that extends rearward from the head pipe are concentrated. The seven-frame structure of the automatic 24@omi is characterized in that the tubes are connected by a box-shaped connecting member formed of an inner mold and an outer mold, and the connecting member is provided with the pivot portion. .