JPS6341794B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pipe frame for a motorcycle.

[Conventional technology]

For example, a pipe frame used in a small two-wheeled motor vehicle includes a pair of left and right main pipes that support an engine and extend in the front-rear direction. The rear ends of these main pipes stand upward to form a seat pillar tube, and the upper ends of the seat pillar tubes are welded to the sides of a pair of left and right seat rails that support the seat and extend in the front and back direction. has been done.

[Problem to be solved by the invention]

However, in conventional pipe frames, the seat pillar tube, which remains hollow, and the seat rail are overlapped and welded, so when the entire pipe frame is viewed from the front or side, the welded portion is There was a risk that the seat rail would protrude significantly and a portion of the seat rail would become wide, impairing the riding posture, and there was room for improvement in this respect.

Therefore, the present invention is capable of securing sufficient strength at the joint between the seat rail and the seat pillar tube, while preventing this joint from bulging out to the side, and is capable of providing a narrow and easy-to-ride automatic 2. The purpose is to provide pipe frames for wheeled vehicles.

[Means to solve the problem]

Therefore, the present invention is based on a pipe frame for a motorcycle in which the upper end of a seat pillar tube is welded to the middle part of the left and right seat rails that support the seat and extend in the front-rear direction. A flat part that is flattened in the vertical direction is formed at the upper end and the middle part of the seat rail to which the upper end of the seat pillar tube is welded, and the flat parts of the seat pillar tube and the seat rail are overlapped with each other. A flat plate that is welded together and located near the welded part and that straddles between a pipe part that connects to the flat part of the seat pillar tube and a pipe part that connects to the flat part of the seat rail. It is characterized by welded parts.

[Effect]

According to this configuration, since the welded part between the seat pillar tube and the seat rail is made flat, the joint part between these two does not bulge out to the side, and the middle part of the seat rail becomes partially wide. This can be prevented. At the same time, by overlapping the flat parts, the joint portion between the seat pillar tube and the seat rail comes into surface contact, and the joint area increases accordingly, so that the welding length can be increased.

Moreover, in the vicinity of the weld between the seat pillar tube and the seat rail, the plate member that spans between them is not a flat part of the seat pillar tube and the seat rail, but maintains its original cross-sectional shape and is strong. Since the plate member is welded to a sufficient length of the pipe, this plate member connects the rigid parts of the seat pillar tube and the seat rail to each other. Therefore, the joint area and welding length between the seat pillar tube and the seat rail are increased, and sufficient joint strength can be ensured.

Furthermore, since this plate member is flat, it does not take up much width, and even though it is welded across the seat pillar tube and the seat rail, the width of the welded portion does not increase.

〔Example〕

The present invention will be explained below based on an embodiment shown in the drawings.

Figure 1 shows a two-wheeled motor vehicle, in which reference numeral 1 is a frame, 2 is a front fork, 3 is a front wheel, 4 is a seat, 5 is a handle, 6 is a rear wheel, and 7 is a frame 1.
It is a synthetic resin cover that covers the

The frame 1 of this embodiment is of an underbone type as shown in FIGS. 2 to 4, and
Steering head pipe 8 located at its front end
A pair of left and right main pipes 9 extending rearward are welded to the. These main pipes 9 are inclined downward as they proceed rearward, and are raised obliquely rearward and upward in the middle thereof, and this raised portion constitutes a seat pillar tube 10. The upper end portion of this seat pillar tube 10 is flattened in the vertical direction to form a flat portion 11 for connection. In addition, at the rising part of the main pipe 9,
An engine bracket 12 projecting downward is welded to the engine bracket 12, and an engine 13 is supported on the engine bracket 12. The engine 13 is supported in such a manner that the cylinder head 14 faces forward and the cylinder axis is substantially horizontal along the front-rear direction.

By the way, a pair of left and right seat rails 15 are welded to the upper end of the seat pillar tube 10, and these seat rails 15 are arranged substantially horizontally along the front-rear direction. This seat rail 15
To explain the joining structure between the seat pillar tube 10 and the seat pillar tube 10, the seat pillar tube 10 is located approximately in the middle along the axial direction of the seat rail 15.
The portion to be joined with is a flat portion 16 that is flattened in the vertical direction. The flat part 11 of the seat pillar tube 10 is superimposed on the inner surface of this flat part 16.
The peripheral edge of the flat part 16 is welded to the inner surface of the flat part 16.

Near both front and rear sides of the welded portions of the flat portions 11 and 16, plate members 17 and 22 are provided in the shape of flat plates that span between the seat pillar tube 10 and the seat rail 15. The plate members 17 and 22 have a pipe portion 10a connected to the flat portion 11 of the seat pillar tube 10, and a pipe portion 1 connected to the flat portion 16 of the seat rail 15.
5a, and connects the pipe portion 10a of the seat pillar tube 10 and the pipe portion 15a of the seat rail 15 in the vicinity of the welded portions of the flat portions 11 and 16.

Further, a stud bolt 18 is installed between the plate member 17 on the rear side of the flat parts 11 and 16. Both ends of the stud bolt 18 penetrate the plate member 17 and protrude outward, and the upper end of a rear suspension 19 that suspends the rear arm 23 is connected to these protrusions. Therefore,
The plate member 17 has both the function of a gusset for connecting the seat pillar tube 10 and the seat rail 15, and the function of a bracket for attaching the rear suspension 19 to the frame 1.

Further, the front end and the rear end of the seat rail 15 are connected via a connecting member 20, so that when the frame 1 is viewed from above, the seat rail 15 has an elongated loop shape in the front-rear direction. ing.

Note that a fuel tank 21 is disposed inside surrounded by the seat rail 15, and this fuel tank 21 is located below the seat 4.

According to such a configuration, the upper end of the seat pillar tube 10 and the seat pillar tube 1
flat parts 11 and 16 that are flat in the vertical direction, respectively, in the middle part of the seat rail 15 joined to the upper end of the seat rail 15;
Since the flat parts 11 and 16 are overlapped and welded to each other, the joint portion between the seat pillar tube 10 and the seat rail 15 does not bulge out to the outside of the frame 1, and the seat rail 15 It is possible to prevent the middle part from becoming wide.

Moreover, by overlapping the flat parts 11 and 16, the seat pillar tube 10 and the seat rail 15 come into surface contact, increasing the joint area, so that the welding length of the joint can be increased.

At the same time, the plate members 17 and 22 are welded not to the flat parts 11 and 16 of the seat pillar tube 10 and the seat rail 15, but to the high-strength pipe parts 10a and 15a that maintain their original cross-sectional shapes. The members 17 and 22 connect the strong parts of the seat pillar tube 10 and the seat rail 15 to each other. Therefore, the seat pillar tube 10 and the seat rail 1
5 is connected not only by the flat parts 11 and 16 but also by the plate members 17 and 22,
Together with the increase in the joint area and weld length, sufficient joint strength can be ensured.

In addition, since the plate members 17 and 22 are flat, they do not have a wide width, and even though they are welded across the seat pillar tube 10 and the seat rail 15, the width of this joint is not widened. It is possible to obtain a frame 1 that is narrow and easy to ride without having to move.

Furthermore, since the flat portion 11 does not protrude between the seat rails 15, the capacity of the fuel tank 21 is impaired, especially in the case where the fuel tank 21 is disposed between the seat rails 15 as in this embodiment. In addition, there is no need to provide a relief for the frame 1 in the fuel tank 21, and the tank shape can be prevented from becoming complicated.

Further, since the left and right seat rails 15 are connected to each other by the connecting members 20, these connecting members 20 function as cross members, which has the advantage of improving the rigidity of the frame 1.

Note that the pipe frame according to the present invention is not limited to the underbone type shown in the above-described embodiments, but can be similarly implemented to, for example, a cradle type or diamond type.

〔Effect of the invention〕

According to the present invention described in detail above, the joint portion between the seat pillar tube and the seat rail does not bulge out to the side, and it is possible to prevent the seat rail from becoming partially wide. Moreover, the plate members are not welded to the flat parts of the seat pillar tube and seat rail, but to the high-strength pipe parts that maintain their original cross-sectional shapes, and connect these strong parts of the seat pillar tube and seat rail to each other. Therefore, together with the increase in the joint area and welding length due to the overlapping of the flat parts, sufficient joint strength can be ensured.

In addition, since this plate member is flat, it does not take up much width, and even though it is welded across the seat pillar tube and the seat rail, the width of this joint does not widen. This has the advantage of providing a frame that is narrow and easy to ride.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of the motorcycle, FIG. 2 is a side view with the cover, seat, etc. removed, and FIG. 3 is a plan view of the frame. FIG. 4 is a side view of the frame. 4... Seat, 10... Seat pillar tube, 10a, 15a... Pipe section, 11, 16...
... Flat part, 15 ... Seat rail, 17, 22 ...
...Plate member.

Claims (1)

[Scope of Claims] 1. A pipe frame for a motorcycle in which an upper end of a seat pillar tube is welded to an intermediate portion of left and right seat rails that support a seat and extend in the front-rear direction, wherein the upper end of the seat pillar tube is A flat part that is flattened in the vertical direction is formed in the middle part of the seat rail to which the upper end of the seat pillar tube is welded, and the flat parts of the seat pillar tube and the seat rail are overlapped with each other. At the same time as welding, a flat plate member located near the welded part and spanning between a pipe part connected to the flat part of the seat pillar tube and a pipe part connected to the flat part of the seat rail is attached. A pipe frame for a two-wheeled motor vehicle characterized by being welded.