JPH0643198B2 - Motorcycle frame - Google Patents

Description

The present invention relates to a motorcycle frame, and more particularly to narrowing the width of the rear upper portion of the frame.

[Conventional technology]

There are various types of frames for motorcycles, for example,
A head pipe that pivotally supports the front fork is fixed to the front ends of the pair of left and right main pipes, and a rear arm bracket that pivotally supports the rear arm is fixed to the rear ends of the main pipes. There is a so-called double cradle type frame that is connected. In a frame having such a shape, the applicant of the present application has proposed to configure the main pipe with a rectangular pipe in cross section and a vertically long square pipe in order to achieve both weight reduction and high rigidity. (Japanese Patent Application Sho 59-
156868).

[Problems to be Solved by the Invention] Generally, in a motorcycle frame, the width of the rear portion of the frame depends on the width of the rear arm that supports the rear wheel and the distance between the rear arm brackets that pivotally support the rear arm. . The bracket spacing is widened from the viewpoint of improving the rigidity of the pivotal support portion of the rear arm with the recent increase in output of the engine, and the vehicle width of the rear portion of the frame is inevitably widened. On the other hand, a seat is mounted on the upper rear side of the frame, and an occupant sits on the seat. Therefore, if the frame width of this portion is too wide, the thighs or the like may hit, which is uncomfortable.
Therefore, it is naturally required for the motorcycle frame to have a predetermined width.

The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a frame that secures a required width in terms of required rigidity and does not hinder seating of an occupant.

[Means for solving problems]

According to the present invention, in a frame of a motorcycle, a mounting seat is integrally formed on a rear arm bracket made of cast aluminum alloy so as to project inward of a vehicle body, and a lower end portion of a back stay supporting a seat rail is supported by the mounting seat. It has a feature.

[Action]

In the motorcycle frame according to the present invention, since the lower end of the back stay is supported inside the vehicle body, the width of the upper portion of the frame becomes narrower by that amount, and the thighs of the occupant do not hit the frame. Further, in this case, since the back stay is supported by the rear arm bracket made of aluminum alloy casting having high rigidity instead of the thin plate portion such as the main pipe, there is no problem in strength.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 show an embodiment of the present invention. In the figure, reference numeral 2 is a frame of the motorcycle 1, which is a so-called double cradle type. This frame 2
The front ends of the pair of left and right main pipes 4, 4 are welded and fixed to the head pipe 3, and the rear arm brackets 5 are welded and fixed to the rear ends of the main pipes 4, respectively.
And a lower surface of the front portion of each main pipe 4 are connected by a down tube 6. An engine 16 is mounted in a space formed by the main pipe 4, the rear arm bracket 5 and the down tube 6, the lower front portion of the engine 16 is fixed to the down tube 6, and the upper rear portion of the engine 16 is fixed to the rear arm bracket 5. There is.

The left and right main pipes 4 and 4 are made of an aluminum alloy and are formed in a generally U-shape in a plane as shown in FIG. 2. As shown in FIG. In addition, when viewed in cross section, it is a vertically long rectangular tube. Further, the rear end surface of the main pipe 4, that is, the joint surface 4a with the rear arm bracket 5 is formed in an inclined shape that is obliquely upward and rearward of the vehicle body.

A seat rail 9 is provided on the upper surface of the rear end of each main pipe 4.
The front end of is welded and fixed. The seat rail 9 is made of an aluminum alloy square pipe, extends obliquely upward and rearward of the vehicle body, and when viewed in plan, as shown in FIG. 2, the seat rail 9 is bent inward near the upper portion of the rear arm bracket 5 and is constricted. That is, the seat rails 9 and 9 on the left and right of the part
Is smaller than the distance between the rear arm brackets 5 and 5. In addition, 13a and 13b are a fuel tank and an air cleaner mounted on the main pipe.
c is a cover that covers these.

The rear arm bracket 5 is made of cast aluminum alloy, and includes a joint portion 5a extending downward from the main pipe 4, that is, a diagonal rearward direction of the vehicle body, and a pivot portion 5b extending downward from the joint portion 5a. It is a substantially V-shaped object composed of and. Like the joint surface 4a of the main pipe 4, the joint surface 5c at the front end of the joint portion 5a is formed in a slanting shape obliquely upward and rearward of the vehicle body, and the joint surfaces 4a and 5c are welded and fixed to each other. 5d, 5
Reference numerals e and 5f are support holes for mounting the engine, pivoting the rear arm, and mounting the down tube, respectively.

And inside the upper end of each of the rear arm brackets 5,
The mounting seat 5g is integrally formed by projecting inward of the vehicle body.
Further, a stay supporting portion 5h is provided on the mounting seat 5g so as to project obliquely upward and rearward of the vehicle body. The lower end of the back stay 10 is fitted and welded and fixed to the stay supporting portion 5h, and the back stay 10 extends obliquely upward and rearward of the vehicle body. The lower end of the back stay 10 has substantially the same width as the constricted portion of the seat rail 9, and the upper end is fixed to the rear lower surface of the seat rail 9. Further, a side member 11 is fixed between the outside of the stay supporting portion 5h of the mounting seat 5g and the front portion of the seat rail 9, and the side member 11 is a plate-like body curved inward of the vehicle body. Thus, the vicinity of the lower end fixing portion of the back stay 10 is covered from the outside.

Reference numeral 17 denotes an upper cross member fixedly arranged between the left and right mounting seats 5g, and 18 denotes a lower cross member fixedly fixed between the left and right tube mounting support holes 5f.

As described above, in this embodiment, the back stay 10 that substantially determines the width of the rear upper portion of the frame 2 is formed by the mounting seat 5g formed by projecting inside the upper end of the rear arm bracket 5 into the inner cover, that is, the vehicle body. Since the support is provided at the inner position, the width of the rear upper portion of the frame can be narrowed and the thighs of the occupant can be prevented from hitting. Further, in this case, a considerable load such as the weight of the occupant acts on the back stay 10, but in this embodiment, since the back stay 10 is supported by the rear arm bracket 5 made of aluminum alloy casting having high rigidity, the back stay 10 is thin. There is no problem in strength as in the case of being supported by the main pipe 4.

〔The invention's effect〕

As described above, according to the frame of the motorcycle according to the present invention, the rear arm bracket is made of aluminum alloy casting, and the mounting seat is formed on the bracket by projecting inwardly of the vehicle body. Since the vehicle is supported at the inward position of the vehicle body, the width of the rear upper part of the frame can be narrowed, which has the effect of improving the riding comfort of the passenger when sitting.

[Brief description of drawings]

1 is a rear view of a frame according to an embodiment of the present invention, FIG. 2 is a plan view thereof, FIG. 3 is a side view thereof, and FIG. 4 is a side view of a motorcycle to which the above embodiment is applied. . In the figure, 1 is a motorcycle, 2 is a frame, 3 is a head pipe, 4 is a main pipe, 5 is a rear arm bracket, 5g is a mounting seat, 6 is a down tube, 8 is a front fork, 9 is a seat rail, and 10 is a back. Stay, 1
2 is a seat, and 15 is a rear arm.

Claims (1)

[Claims] 1. A rear arm bracket for pivotally supporting a rear arm at a front end of a pair of left and right main pipes fixed to a steering head pipe (hereinafter referred to as a head pipe) pivotally supporting a front fork. In a motorcycle frame in which the rear arm bracket and the front portion of the main pipe are fixedly connected to each other by a down tube below the main pipe, the rear arm bracket is made of an aluminum alloy casting, and the upper end of the bracket is provided. A frame for a motorcycle, characterized in that a mounting seat is integrally formed by projecting inwardly of a vehicle body, and a lower end portion of a backstay for supporting a seat rail on which a seat is mounted is supported by the mounting seat.