JPH0518235Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a body frame for a scooter-type vehicle, which includes a down tube and a lower frame connected to the down tube.

(Prior Art) As a conventional vehicle body frame of this type, the one described in, for example, Japanese Unexamined Patent Publication No. 57-114776 is known. In this structure, the lower end of the down tube is extended rearward, and a pair of lower frames are fixed to each other through gussets provided on both sides of the extended portion.

(Problems to be Solved by the Invention) In the above-mentioned conventional body frame, since the lower frame is connected to the rear of the extended portion of the down tube, that is, the curved portion, the body frame that acts on the curved portion is The maximum bending stress must be borne only by the strength of the down tube, and the down tube must have a large diameter so as to be able to withstand the bending stress.

The present invention solves the above-mentioned problems, makes it possible to configure the down tube with a small diameter, and
It is an object of the present invention to provide a body frame for a scooter type vehicle that constitutes a flat plate-shaped space extending in the front-rear direction with both lower frames serving as cover members between both lower frames.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a down tube that extends diagonally downward from the head pipe and has a curved portion that curves backward at the lower end, and a lower end of the down tube. A body frame of a scooter type vehicle comprising a pair of lower frames connected to and extending rearward, wherein a curved part that curves inwardly and upward is formed at the front end of the lower frames, and the front ends of the lower frames are connected to the lower frame. The tube is fixed to both sides directly above the curved part, a cross member is fixed to the front ends of both lower frames, and the lower end of the down tube is fixed to the center of the cross member.

(Function) By fixing the front end of the lower frame directly above the curved part of the down tube and fixing the lower end of the down tube to the cross members of both lower frames, the bending stress acting on the curved part is absorbed by the cross member. It can be distributed between the members and the front ends of both lower frames.

On the other hand, by configuring the connecting portion between the down tube and the lower frame as described above, the connecting portion can be positioned much further forward than in the conventional case.

(Example) Referring to FIGS. 1 to 3, 1 indicates a body frame of a scooter type vehicle, and the body frame 1
The vehicle is composed of a head pipe 2, a down tube 3 connected to the head pipe 2, and a pair of lower frames 4 connected to the down tube 3, and constitutes the frame of the vehicle body.

The down tube 3 has an upper end connected to the head pipe 2.
A curved part 3a is formed at the lower end of the curved part 3a, which extends diagonally downward, and is connected to both lower frames 4, 4 at the right upper part 3b of the curved part 3a. The lower frames 4, 4 are connected to each other via a front cross member 5 provided at the front end of the lower frames 4, 4.

Both lower frames 4, 4 are located symmetrically across the axis of the vehicle body, and each lower frame 4 extends rearward from the down tube 3 substantially horizontally, curves in an S-shape at an intermediate portion 4a, and further The upper part extends to the rear.
The front cross member 5, the intermediate cross member 6, and the rear cross member 7 interposed between the lower frames 4, 4 allow the lower frames 4,
4 are connected at three locations to maintain rigidity.

Both the lower frames 4, 4 have curved parts 4b, 4b curved inwardly and upwardly at their front ends, and the tips of the curved parts 4b, 4b, that is, the lower frames 4, 4. C-shaped flat connecting parts 4c, 4c are formed at the front end, and the lower frames 4, 4 are lowered by sandwiching the right upper part 3b of the down tube 3 from both sides with the connecting parts 4c, 4c. It sticks to tube 3. On the other hand, the front cross member 5 connecting the lower frames 4 is fixed to the rising portions of the curved portions 4b, and the center of the front cross member 5 is fixed to the lower end of the down tube 3. Thus, a total of three locations constitute a connecting portion between the down tube 3 and both lower frames 4, 4.

A step 8 of the vehicle body extends above a portion extending substantially horizontally from the curved portions 4b, 4b to the intermediate portions 4c, 4c of the lower frames 4, 4, and the lower frames 4, 4 and the step 8 A fuel tank 9 whose front part is thinner than the rear part and whose both sides are wedge-shaped is housed in between. The fuel tank 9 is made of a steel plate having a welded flange 9a, and the front portion is fixed to the curved portions 4b, 4b of the lower frames 4, 4 by front stays 10, 10, and the rear portion is formed into a figure 8-shaped middle portion 4a,
Rear stay 11 fixed to the rising part of 4a,
11, and is attached so that its lower part is fitted into a space 12 formed by both lower frames 4, 4, a front cross member 5, and an intermediate cross member 6. Further, a step 8 is provided at the upper stage of the front stays 10, 10 and the rear stays 11, 11.
is supported. Inlet 9b of fuel tank 9
is provided on the right side in the direction of travel of the vehicle body, and a lid 8b is provided at the bottom of the center cover 8a below the seat opposite to this, and as shown in FIG. 4, the lid 8b is opened to inject fuel. It can be done.

Reference numeral 13 in the figure indicates a stay for the main stand 13a.
It is fixed to the stay 13 so that the traveling wind passes through the space surrounded by the stay 13 so that it does not become an obstacle to the traveling wind flowing toward the engine side. The base of the stay 13 is reinforced with a bracket 13b, which also serves as a protection member for the rear of the fuel tank 9.

With the above configuration, the connection portion between the down tube 3 and both lower frames 4 where the maximum bending stress occurs in the vehicle body frame 1 is the curved portion 3a of the down tube 3, the curved portion 4b of both lower frames 4, 4,
4b and the front cross member 5, the strength of the frame is increased, and the stress of the down tube 3 is reduced by the curved portions 4b, 4b of both lower frames 4,
4b and the front cross member 5,
The down tube 3 can be configured to have a small diameter.

On the other hand, since the connecting portion is located at the front compared to the conventional one, there is a guard between the lower frames 4, 4, the front cross member 5, the intermediate cross member 6, and the bracket 13b. A space 12 that is optimal in terms of rigidity can be configured for the fuel tank 9 as a member.

In this embodiment, the right upper part 3b of the down tube 3 and the front ends of both lower frames 4, 4 are directly connected, but they may be connected via a bracket. Further, although the fuel tank 9 is provided in the front space 12, a storage space may be provided therein.
Furthermore, an under cover 14 may be provided below the lower frame 4 to protect the frame 4. In this case, as shown in FIG. The bracket 13b can also serve as a protection member for the cover 14, and can also serve as a reinforcing member for the cover 14 by fixing the undercover 14 and the bracket 13b.

(Effects of the invention) As described above, according to the invention, the front end of the lower frame is fixed directly above the curved part of the down tube, and the lower end of the down tube is fixed to the cross members of both lower frames. By configuring the connection portion between the down tube and both lower frames so that the front end portions of both lower frames can be used as reinforcing materials for the curved portion, it is possible to form the down tube to be small in diameter and lightweight, In addition, the connecting portion configured in this way is located at the front compared to the conventional one, and forms a useful space extending in the front-rear direction between both lower frames with the lower frames serving as cover members. It has the effect of being able to.

[Brief explanation of drawings]

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a partially cutaway side view of the present invention applied to a scooter type vehicle, and Fig. 4 is a perspective view of the area around the center cover. It is a diagram. 1...Vehicle frame, 2...Head pipe, 3
...Down tube, 3a...Curved part, 3b...
Right upper part, 4... lower frame, 4b... curved part,
5...Front cross member.

Claims (1)

[Scope of utility model registration request] A body frame for a scooter type vehicle, comprising: a down tube extending diagonally downward from a head pipe and having a rearwardly curved curved portion at its lower end; and a pair of lower frames connected to the lower end of the down tube and extending rearward; A curved portion that curves inwardly and upwardly is formed at the front end of both lower frames, and the front ends of both lower frames are fixed to both sides of the down tube directly above the curved portion, and a cross is formed at the front end of both lower frames. 1. A vehicle body frame for a scooter type vehicle, characterized in that a member is fixed to the cross member, and a lower end of the down tube is fixed to the center of the cross member.