JPH0777876B2 - Motorcycle frame - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motorcycle frame in which a pair of left and right frame members extending obliquely downward and rearward is connected to a head pipe.

[Conventional technology]

In this type of frame, the present applicant has recently developed a pair of left and right frame members that connect the head pipe and the pivotal support portion of the rear arm in a vertical direction in order to achieve both weight reduction and high rigidity. We proposed that it be composed of a vertically long flat square pipe, and have already completed the application as “Japanese Patent Application No. 59-156868”.

[Problems to be Solved by the Invention]

By the way, in the motorcycle in which the carburetor of the engine is inserted between the left and right frame members for the convenience of the engine layout, if the frame member is vertically long as in the above-mentioned prior art, this frame member is located outside the carburetor. Will pass through.

However, since the screw for idle adjustment is usually located on the outer surface of the carburetor, the screw is laterally covered by the frame member. For this reason,
There is a problem that the frame member interferes with the operation of adjusting the screw.

The present invention has been made based on such a circumstance, and the idle adjustment work of the carburetor can be easily performed from the outside of the frame member, and the frame is formed by using the guide pipe for guiding the tool. It is an object of the present invention to provide a frame for a motorcycle that can increase the rigidity of the member, prevent vibration of the side surface of the frame member, and suppress noise from the frame member.

[Means for solving problems]

In order to achieve the above object, a frame of a motorcycle according to the present invention has a head pipe pivotally supporting a front fork, and a rectangular tubular shape that extends obliquely downward and rearward from the head pipe and has a vertically long vertical cross section. It is provided with a pair of left and right frame members.

The frame member is provided with a pair of frame materials having a U-shaped cross section having a flat plate-shaped side wall extending in the vertical direction and a flange wall extending in the vehicle width direction from the upper and lower edges of the side wall. The raw materials are arranged side by side in the vehicle width direction, and the front end portions of the respective flange walls are overlapped with each other and welded to form a square tubular shape having a flat cross section. It passes through the outside of the carburetor and extends to the rear of the engine, and is provided on the outside of the carburetor at the rear part of the frame member, passing through the side wall of each of the frame materials that is the left and right side faces of the frame member A through hole for inserting a tool is formed facing the adjuster for idle adjustment, a guide pipe is inserted through the through hole, and both ends of the guide pipe are connected to the side of the frame material. It is characterized in that it has respectively welded to.

[Action]

With this configuration, a rod-shaped tool such as a driver can be guided to the adjuster through the through hole, and idle adjustment of the carburetor can be performed from the outside of the frame member. Moreover, since the tool reaches the adjuster while being guided by the inner surface of the guide pipe, the insertion end of the tool does not get caught in the opening edge of the through hole on the carburetor side, and the tool insertion work can be easily performed. .

Further, since both end portions of the guide pipe are welded to the side wall of the left and right frame materials and function as a cross member that connects these side wall, each side wall is not easily deformed. Therefore, the change in the cross-sectional shape of the frame member is suppressed, and the rigidity of the frame member is improved.

In addition, the frame member has a vertically elongated flat cross-sectional shape, and the area of the side wall of the frame material, which is the side surface of the frame member, is larger than the wall thickness, which is disadvantageous in increasing the surface rigidity. come. However, as described above, since the side wall is connected by the guide pipe and its deformation is suppressed, the side wall is less likely to vibrate, and noise from the frame member can be prevented.

Example of Invention

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

In the figure, reference numeral 1 is a frame made of an aluminum alloy, and is provided with a head pipe 2 vertically installed at the front end thereof. A front fork 3 is pivotally supported on the head pipe 2. The head pipe 2 is welded with a pair of left and right frame members 4, 4 that extend rearward and obliquely downward in a substantially straight line in a side view.

As shown in FIG. 2, the frame members 4 and 4 are made by abutting and welding the frame materials 5a and 5b having a substantially U-shaped cross-section with one side open, and the cross-sectional shape is up and down. It is formed in a flat rectangular tube shape that is vertically long in the direction. That is, each frame material 5a, 5b integrally includes a side wall 51 extending in the vertical direction and upper and lower flange walls 52a, 52b extending in the vehicle width direction from the upper and lower edges of the side wall 51. Then, the one frame material 5a positioned outside in the vehicle width direction
Inside the flange walls 52a, 52b, the flange walls 52a, 52b of the other frame material 5b located on the vehicle width direction side are fitted, and by welding the fitting portions, a frame member having a flat cross section is formed. It is assembled as 4,4.

Further, the frame members 4, 4 are formed such that the longitudinal dimension of the front end portion connected to the head pipe 2 is substantially equal to the axial length of the head pipe 2 in order to enhance the strength of the connecting portion with the head pipe 2. The vertical dimension of these frame members 4, 4 is gradually reduced as it goes rearward.
Therefore, the side surfaces of the frame members 4, 4 are formed in a taper shape as they go rearward.

The frame members 4, 4 are expanded to the outside in the vehicle width direction immediately after the head pipe 2, and extend rearward from the expanded ends in substantially parallel to each other. A bracket 6 for pivotally supporting the rear arm 6a is connected to each. A down tube 8 is installed between the bracket 6 and the cross tube 7 connecting the front ends of the frame members 4, 4.

Left and right seat rails 9 extending rearward are welded to the upper rear surfaces of the frame members 4, 4, and a back stay 10 is provided between the rear portion of the seat rail 9 and the bracket 6.
Has been erected.

By the way, a parallel two-cylinder engine 11 is mounted between the frame members 4, 4 and the down tube 8. The engine 11 has a substantially upright cylinder 12, and behind the cylinder 12, a pair of carburetors 13, 13 are arranged side by side. The vaporizers 13, 13 are inserted between the rear portions of the frame members 4, 4, and the frame members 4, 4 pass outside the vaporizers 13, 13.

On the outer surface of each carburetor 13, 13, an adjuster for idle adjustment, that is, an idle screw 15 for adjusting the opening / closing of the throttle valve 14 when fully closed is arranged.
As shown in FIG. 2, the head portion 15a of the idle screw 15 is closely opposed to the inner surfaces of the frame members 4, 4 which are opposed to each other. Then, through holes 16a, 16b are opened in the left and right side surfaces 4a, 4b of the frame members 4, 4, respectively. The through holes 16a and 16b are formed in the side wall 51 of the frame materials 5a and 5b, and are located coaxially with each other. Through holes 16a, 16b
Is formed to have a larger diameter than the head portion 15a of the idle screw 15 and faces the side portion of the head portion 15a.

Therefore, the idle screw 15 is visible from the outside of the frame members 4, 4 through the through holes 16a, 16b,
A rod-shaped tool 17 such as a driver for rotating the idle screw 15 is inserted from the outside of the frame members 4, 4 through the through holes 16a, 16b.

In each frame member 4, 4, a hollow cylindrical guide pipe 18 is bridged between the through holes 16a, 16b.
Both ends of the guide pipe 18 are welded to the opening edge portions of the through holes 16a and 16b, and the side wall 51 of the left and right frame materials 5a and 5b.
Are connected to each other. Therefore, the tool 17 is inserted into the guide pipe 18 and guided to the idle screw 15 via the inner peripheral surface of the guide pipe 18.

According to such a configuration, the left and right frame members 4, 4,
Through hole 1 facing the adjusting screw 15 of the vaporizer 13, 13.
Since 6a and 16b are formed, the rod-shaped tool 17 can be guided to the adjusting screw 15 through the through holes 16a and 16b,
Idle adjustment can be performed from the outside of the frame members 4, 4.

Moreover, since the guide pipe 18 is bridged between the through holes 16a and 16b, when the rod-shaped tool 17 is inserted into the through holes 16a and 16b, the insertion portion of the tool 17 is on the inner surface of the guide pipe 18. Guided to reach the adjusting screw 15. Therefore, the insertion tip of the tool 17 is not caught on the opening edge of the through hole 16b in the back near the vaporizers 13, 13.
The tool 17 can be smoothly inserted, and the workability is improved.

In addition, the both ends of the guide pipe 18 are simply through holes 16a, 16b.
The guide pipe 18 is not only inserted into the frame material 5a, 5b, but also welded to the side wall 51 of the pair of frame materials 5a, 5b forming the frame members 4, 4.
Will function as a cross member that connects the side wall 51 of the. Therefore, the side wall 51 is less likely to be deformed, and particularly when the frame members 4 and 4 have a structure in which a pair of frame materials 5a and 5b are butted and welded to each other, a change in the cross-sectional shape of the frame members 4 and 4 is suppressed. The rigidity of these frame members 4, 4 is improved.

Further, since the frame members 4, 4 have a flat cross-sectional shape that is vertically long in the vertical direction, the side wall 51 of the frame materials 5a, 5b forming the side faces 4a, 4b has a larger area than the wall thickness. Therefore, there is a disadvantage in terms of rigidity. However, as described above, the left and right side walls 51 of each frame member 4, 4 are joined by the guide pipe 18 as described above, and the deformation thereof is suppressed. Even if the vibration is transmitted, the side wall 51 is less likely to vibrate. Therefore, even if the frame members 4 and 4 have a rectangular tube shape with a vertically long cross section, noise from the frame members 4 and 4 can be prevented, and silent operation can be performed.

In the above-described embodiment, the frame member is tapered toward the rear, but the present invention is not limited to this, and the frame member may be extended rearward with the same width as the front end portion connected to the head pipe.

〔The invention's effect〕

According to the invention described in detail above, since the insertion portion of the tool reaches the adjuster of the carburetor by being guided by the inner surface of the guide pipe, the tool can be easily inserted into the through hole from the outer side of the frame member. Therefore, the workability at the time of idle adjustment of the carburetor is improved.

Moreover, since both ends of the guide pipe are not simply inserted into the through holes but also welded to the side wall of the frame material welded to each other, the guide pipe connects the side wall of the frame material with the cross. This will function as a member, and this side wall will not easily deform. Therefore, the change in the cross-sectional shape of the frame member is suppressed, and the rigidity of the frame member is improved.

In addition, since the deformation of the side wall is suppressed by the guide pipe, even if the vibration of the engine is transmitted to the frame member, the side wall is less likely to vibrate. Therefore, although the frame member is formed in a rectangular tube shape having a vertically long cross section, there is an advantage that noise from the frame member can be prevented and quiet operation can be performed.

[Brief description of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a side view of a motorcycle, Fig. 2 is a sectional view taken along line II-II in Fig. 1, and Fig. 3 is a side view around a carburetor. Drawing and Drawing 4 are sectional views of a vaporizer. 1 …… frame, 2 …… head pipe, 3 …… front fork, 4 …… frame member, 5a, 5b …… frame material, 11 …… engine, 13 …… carburetor, 15 …… adjuster (adjust screw) ), 16a, 16b …… through hole, 17 …… tool, 18 …… guide pipe, 51 …… side wall, 52a, 52b …… flange wall.

Claims (1)

[Claims] 1. A head pipe pivotally supporting a front fork, and a pair of left and right frame members extending obliquely downward and rearward from the head pipe and having a vertically long rectangular cross section having a flat cross section. In the frame of the motorcycle, the frame member is a pair of frame materials having a U-shaped cross section having a flat plate-shaped side wall extending in the vertical direction and a flange wall extending in the vehicle width direction from the upper and lower edges of the side wall. These frame materials are arranged side by side in the vehicle width direction, and the front ends of their flange walls are overlapped with each other and welded together to form the above-described flat tube having a flat cross section. , Extends to the rear of the engine through the outside of the carburetor of the engine, and on the rear of this frame member, the left and right side surfaces of this frame member Note: A tool insertion hole is formed through the side wall of each frame material, facing the adjuster for idle adjustment provided on the outer surface of the carburetor, and the guide pipe is inserted into this hole. A frame for a motorcycle characterized in that both ends of the guide pipe are welded to the side wall of the frame material.