JPH07285483A - Body frame for motorcycle - Google Patents

Abstract

PURPOSE:To provide rigidity in a gusset while decreasing a number of part items to lighten the weight, through reinforcing by the gusset. CONSTITUTION:In a body frame 1 for a motorcycle having a single main frame 8 extended rearward from an upper part of a head pipe 2 to be connected to a rear frame F and a single down tube 21 extended down rearward from a lower part of the head pipe 2, a gusset 33, connecting right/left plates 31, 32 into a bean-jam-filled wafers-shape, is welded to be integrally formed in a part surrounded by the head pipe 2, main frame 8 and the down tube 21. In an intermediate part of this gusset 33, a space window 34 is formed between itself and the main frame 8, and also irregularity is formed in plane parts of the right/left plates 31, 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body frame of a motorcycle, and more particularly to a vehicle body frame of a motorcycle which is suitable for traveling on an uneven terrain.

[0002]

2. Description of the Related Art In a vehicle body frame of a motorcycle, a front wheel is supported on a front side via a front fork, a rear arm is supported on a rear side by a link mechanism or a rear suspension, and a rear wheel is supported on the rear arm. An engine is mounted on the main frame and down tube in the center.

For example, in a motorcycle or the like traveling on an uneven terrain, there is one shown in FIG. 12 in order to secure strength and rigidity. A vehicle body frame 100 of this motorcycle extends rearward from an upper portion of a head pipe 101, for example, a seat rail 1
There is one main frame 103 connected to the rear frame 02 and the like, and one down tube 104 extending downward and rearward from the lower portion of the head pipe 101. And a tension pipe 106 is welded and connected to the rear of the gusset 105. Further, the front side of one end of the tension pipe 106 and the gusset 105
A gusset 107 is welded from the left and right between the rear side and the down tube 104, and a gusset 108 is also welded from the left and right between the rear side and the down tube 104. Further, at the other end of the tension pipe 106, there is one in which a gusset 109 is welded from the left and right between the rear side and the main frame 103.

[0004]

As described above, in the vehicle body frame, the gusset and the tension pipe are separately welded and reinforced between the main frame and the down tube, and the welded portions at both ends of the tension pipe are further reinforced. Since the gusset is welded and reinforced, there are problems that the number of parts is large and the weight is heavy.

Therefore, for example, a large gusset from the head pipe to the range where the main frame and the tension pipe of the down tube are welded can be welded from the left and right to reinforce, and in this case, the number of parts is reduced. However, the weight increases. In addition, when a strong impact is applied to the vehicle body frame during traveling, it is difficult to secure the rigidity of the large flat portion of the gusset, and the flat portion may be corrugated and deformed.

The present invention has been made in view of the above circumstances, and provides a vehicle body frame of a motorcycle in which the number of parts is reduced and the weight is reduced by reinforcing the gusset, and the gusset has rigidity. Is intended.

[0007]

In order to solve the above-mentioned problems, a vehicle body frame for a motorcycle according to a first aspect of the present invention comprises a main frame extending rearward from an upper portion of a head pipe and connected to a rear frame; In a vehicle body frame of a motorcycle having one down tube extending downward and rearward from a lower portion of a head pipe, left and right plates are joined in a monaca shape in a portion surrounded by the head pipe, the main frame and the down tube. The gusset is welded and integrated, and a space window is formed between the gusset and the main frame, and unevenness is formed in the plane portions of the left and right plates.

A motorcycle frame according to a second aspect of the present invention is characterized in that bent ridges are formed at the ends of the flat portions of the left and right plates of the gusset.

[0009]

According to the first aspect of the present invention, the number of parts is reduced by welding and integrating a gusset having left and right plates joined in a monaca shape to a portion surrounded by the head pipe, the main frame and the down tube. While reinforcing the head pipe, main frame and down tube.

Moreover, a space window is formed in the middle of the gusset between the gusset and the main frame, and the gusset is lightweight, and the parts forming the space window of the gusset are connected by welding to have a rib function. However, this improves the strength and rigidity of the gusset.

Further, the flat portions of the left and right plates of the gusset have improved strength and rigidity due to the unevenness, and even if a strong impact is exerted on the vehicle body frame during traveling, the large flat portions of the left and right plates are prevented from waving and are deformed. Can be prevented.

According to the second aspect of the present invention, bent convex portions are formed at the ends of the flat portions of the left and right plates of the gusset, and these convex portions function as ribs, and the strength of the gusset is
The rigidity is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a vehicle body frame of a motorcycle according to the present invention will be described below in detail with reference to the accompanying drawings. 1 is a side view of the motorcycle, FIG. 2 is a side view of the vehicle body frame, FIG. 3 is a view seen from the direction A in FIG. 2, and FIG. 4 is a view seen from the direction B in FIG. Is a side view of the gusset and FIG. 6 is FIG.
5 is a sectional view taken along line VI-VI of FIG. 7, FIG. 7 is a sectional view taken along line VII-VII of FIG. 5, FIG. 8 is a sectional view taken along line VIII-VIII of FIG.
5 is a sectional view taken along line IX-IX in FIG. 5, and FIG. 10 is XX in FIG.
11 is a sectional view taken along line XI-XI in FIG.

This motorcycle is used for running on rough terrain, for example, for motocross competition. A front fork 3 is supported by a head pipe 2 which constitutes a vehicle body frame 1, and a lower end portion of the front fork 3 is supported. The front wheel 4 is provided in the. Further, a front fender 5 is attached to the front fork 3, and the front fender 5 is a fixed fender that is not interlocked with the vertical movement of the front wheels 4.

A front portion 8a of one main frame 8 is welded to an upper portion of the head pipe 2 and extends rearward and is connected to a mounting portion 7 of the rear suspension 6. The main frame 8 has a circular cross section, and a rear portion 8b thereof is welded to a mounting portion 7 of the rear suspension 6 as shown in FIG. 3, and a pair of left and right rear pipes 9 are welded to the mounting portion 7 to form a rear pipe 9 Rear arm brackets 10 are respectively welded to the lower portions of the. A rear pipe 9 is welded to the mounting portion 7 of the rear suspension 6, and a seat rail 16 is connected to the mounting portion 7, which form a rear frame F.

The left and right rear arm brackets 10 are connected by a cross member 90 to be integrated. A rear arm pivot 11 is provided between the rear arm brackets 10, a rear arm 12 is pivotally supported by the rear arm pivot 11, and a rear wheel 13 is provided at a rear portion of the rear arm 12.
Is supported.

The rear arm 12 is supported by the vehicle body side mounting portion 15 by the link mechanism 14, and the vehicle body side mounting portion 15 is welded to the cross member 90. The link mechanism 14 supports the lower portion 6a of the rear suspension 6, and the mounting portion 7 supports the upper portion 6b of the rear suspension 6. In this way, the rear arm 12 is swingably provided in the vertical direction by the link mechanism 14 and the rear suspension 6.

The mounting portion 7 includes a front portion 16 of the seat rail 16.
a is attached to the rear portion 16b, the upper portions 17a of the left and right back stays 17 are welded, and the lower portion 17b is attached to the attachment portion 18 welded to the rear arm bracket 10. A fuel tank 19 is arranged so as to straddle the upper portion of the main frame 8, and the front portion of the seat 20 placed on the seat rail 16 covers the upper portion of the fuel tank 19.

An upper portion 21a of one down tube 21 extending downward and rearward is welded to the lower portion of the head pipe 2. The down tube 21 is formed to have a rectangular cross section, and a lower portion 21b thereof is welded from both sides with front portions 22a of the left and right support frames 22 as shown in FIG.
A gusset 23 between the inner side of the lower tube 21 and the lower portion 21b of the down tube 21 is welded and reinforced. The rear portion 22b of the support frame 22 is welded to the cross member 90, and the connection frame 24 is further welded between the rear portion 22b of the support frame 22 and the rear arm bracket 10 for reinforcement.

A pair of mounting cylinders 25 are fixed to the central portion of the support frame 22, and an engine mounting bracket 26 is applied to the mounting cylinders 25 from the outside, and screws 27 are mounted on the mounting cylinders 25.
The engine mounting bracket 26 is mounted by screwing on. An engine mounting bracket 28 is welded to the rear portion 22b of the support frame 22.

The upper part of the head pipe 2 and the main frame 8
A gusset 29 is welded to the upper part of the front part of the head pipe 2, and a gusset 30 is similarly welded to the lower part of the head pipe 2 and the upper part 21a of the down tube 21. Thus, the gussets 29 and 30 are welded from above and below. It is reinforced by connecting them together.

The head pipe 2, the main frame 8 and
In a portion surrounded by the down tube 21, a gusset 33 in which left and right plates 31 and 32 are joined in a monaca shape is welded and integrated, and a space window 34 between the gusset 33 and the main frame 8 is formed. And the unevenness is formed on the plane portions of the left and right plates 31, 32.

That is, the left and right plates 3 of the gusset 33
Reference numerals 1 and 32 denote portions 31a and 32a forming the space window 34.
The outer engine side portions 31b and 32b are welded. In this way, by forming the space window 34 between the gusset 33 and the main frame 8, the gusset 33 is lightweight and the space window 34 of the gusset 33 is formed.
The part that forms is welded and has the function of a rib,
This improves the strength and rigidity of the gusset 33.

Also, the left and right plates 3 of the gusset 33
1, 32 are portions 31c to be welded to the head pipe 2,
32c, parts 31d and 3 to be welded to the main frame 8
2d, parts 31e, 3 to be welded to the down tube 21
2e is not welded, but by welding these parts to the head pipe 2, the main frame 8 and the down tube 21, the three members are integrated and reinforced.

The left and right plates 31 of this gusset 33,
The flat surface of 32 includes concave portions 31f and 32f and a convex portion 31f.
Roughness is formed by g and 32g, and the left and right plates 3
The flat portions 1 and 32 have concave portions 31f and 32f and convex portions 31f.
By forming g and 32g, strength and rigidity are improved. Therefore, even when a strong impact is applied to the vehicle body frame 1 during traveling, the large flat surface portions of the left and right plates 31 and 32 are prevented from waving and can be prevented from being deformed.

Further, convex portions 31h and 32h are formed by bending at the ends of the flat portions of the left and right plates 31 and 32, and the convex portions 31h and 32h have a rib function, whereby the gusset 33 of the gusset 33 is formed. The strength and rigidity of the left and right plates 31, 32 are improved.

Left and right plates 31, 32 of the gusset 33
A pair of mounting cylinders 40 are welded to the rear part, and the engine mounting bracket 41 is applied to the mounting cylinders 40 to secure the screws 4
2 is screwed to the mounting cylinder 40 and the engine mounting bracket 41 is attached.
Is attached.

Below the gusset 33, an engine 43 is mounted in a space surrounded by the rear pipe 9, the support frame 22, and the rear arm bracket 10 from the side. In the engine 43, an upper portion of a cylinder 43a is supported by an engine mounting bracket 41 by tightening bolts 44, a front side of the engine case 43b is similarly supported by an engine mounting bracket 26 by tightening bolts 45, and a lower side of the engine mounting bracket 28 is supported. The bolts 46 are fastened to and supported by the rear arm bracket 10, and the rear side is supported by the rear arm bracket 10 via the rear arm pivot 11.

A carburetor 47 is connected to the rear side of the cylinder 43a of the engine 43, and the carburetor 47 is further connected to the duct 4.
The air cleaner 49 is connected via 8 and the duct 4
8 is arranged close to the left side of the vehicle body so as not to interfere with the rear suspension 6. Further, the air cleaner 49 is arranged behind the rear suspension 6 and below the seat 20 so as not to interfere with the rear suspension 6. An exhaust pipe 5 is provided in front of the cylinder 43a of the engine 43.
0 is connected, and the exhaust pipe 50 is bent from the left side of the vehicle body to the right side below the front side of the support frame 22 and extends from the right side to the rear side.

An ignition unit 51 is arranged at the position of the space window 34 formed between the gusset 33 and the main frame 8. The ignition unit 51 is supported by a bracket 52 welded to the main frame 8, and the ignition unit 51 is arranged using the space window 34.

[0031]

As described above, according to the first aspect of the invention, the gusset having the left and right plates joined in a monaca shape is welded to and integrated with the portion surrounded by the head pipe, the main frame and the down tube. As a result, the head pipe, main frame, and down tube can be reinforced while reducing the number of parts.

Moreover, a space window is formed in the middle of the gusset between the gusset and the main frame, and the gusset is lightweight, and the portions forming the space window of the gusset are connected by welding to provide a rib function. The strength and rigidity of the gusset are improved.

Further, the flat portions of the left and right plates of the gusset have improved strength and rigidity due to the unevenness, and even if a strong impact is applied to the vehicle body frame during traveling, the large flat portions of the left and right plates are prevented from waving and are deformed. Can be prevented.

According to the second aspect of the present invention, since bent convex portions are formed at the ends of the flat portions of the left and right plates of the gusset, the convex portions function as ribs, and the strength and rigidity of the gusset are improved.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle.

FIG. 2 is a side view of a body frame.

FIG. 3 is a view seen from the direction A in FIG.

4 is a view seen from the direction B in FIG.

FIG. 5 is a side view of the gusset.

6 is a sectional view taken along line VI-VI of FIG.

7 is a sectional view taken along the line VII-VII of FIG.

8 is a sectional view taken along the line VIII-VIII of FIG.

9 is a sectional view taken along line IX-IX in FIG.

10 is a cross-sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

FIG. 12 is a side view of a body frame of a conventional motorcycle.

[Explanation of symbols]

 1 Body Frame 2 Head Pipe 6 Rear Suspension 7 Attachment 8 Main Frame 21 Down Tube 31, 32 Plate 33 Gusset 34 Space Window F Rear Frame

Claims (2)

[Claims] 1. A motorcycle body frame having one main frame extending rearward from an upper portion of a head pipe and connected to a rear frame, and one down tube extending rearward downward from a lower portion of the head pipe, wherein the head is provided. In the part surrounded by the pipe, the main frame and the down tube, a gusset in which the left and right plates are joined in a monaca shape is welded and integrated, and a space window is formed between the main frame and the middle part of the gusset. A vehicle body frame for a motorcycle, characterized in that the flat surfaces of the left and right plates are provided with projections and depressions. 2. The vehicle body frame for a motorcycle according to claim 1, wherein bent ridges are formed at ends of flat portions of the left and right plates of the gusset.