JPH08216960A - Car body frame for motorcycle - Google Patents

Abstract

PURPOSE: To provide the car body frame of a motorcycle which is so constituted as to have excellent welding and painting workability during manufacture and besides reduce the influence of a heat on a fuel feed system, such as a carburetor, and an intake system, such as an air cleaner. CONSTITUTION: The car body frame 1 of a motorcycle comprises a truss main frame 4 to support a member ranging from a front fork formed by welding in a truss-form manner a plurality of pipe members ; and a rear arm bracket to support a rear arm formed of a light metallic material. The upper part of the rear arm bracket is coupled to approximately the central part in a longitudinal direction of the truss main frame 4 by means of a fastening member 26.

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.

[0002]

2. Description of the Related Art In a vehicle body frame of a motorcycle, for example, a pair of left and right wide main frames are welded to a head pipe, and a rear frame bracket is integrally formed at the rear ends of the pair of left and right main frames. However, there is one in which a rear arm is pivotally supported on a rear frame bracket and a seat rail or the like is attached to the rear end of the main frame. There is also a rear frame bracket fixed to a rear end portion of a pair of left and right main frames by welding.

[0003]

By the way, a structure in which a rear frame bracket is integrally formed at the rear end portions of a pair of left and right main frames or fixed by welding and a down tube which descends from the vicinity of the head pipe toward the front of the engine. In such a structure, since the size of the main frame in the height direction is large, workability such as welding and painting is poor. In addition, a separate step for attaching the seat rail or the like to the main frame or the rear arm bracket is required, which complicates the manufacturing process.

Furthermore, since the engine is suspended below a pair of wide main frames on the left and right, and the upper part of the engine is covered with a fuel tank mounted on the main frame, heat is trapped in the space above the engine, It is difficult to smoothly release hot air to the outside, and a fuel supply system such as a carburetor and an intake system such as an air cleaner are affected by heat, and the temperature of fuel and intake air to the engine becomes high.

The present invention has been made in view of the above circumstances, has good workability in welding and coating during manufacturing, and reduces the influence of heat on a fuel supply system such as a carburetor and an intake system such as an air cleaner. However, it is an object of the present invention to provide a motorcycle body frame that is effective for improving output.

[0006]

In order to solve the above-mentioned problems and to achieve the object, the invention according to claim 1 comprises a front fork and a seat formed by welding a plurality of pipe members in a truss shape. A truss main frame for supporting the members and a rear arm bracket for supporting a rear arm made of a light metal material, and the upper part of the rear arm bracket is connected to the upper part of the rear arm bracket by a fastening member at a substantially central lower part in the front-rear direction of the truss main frame. It has a feature.

According to a second aspect of the present invention, there is provided a motorcycle body frame, wherein the truss main frame includes a head pipe, a pair of left and right upper and lower tank rails, a member connecting between the pair of left and right upper and lower tank rails, and a pair of left and right seats. A rail and a back stay, and a cross tube connecting between the pair of left and right seat rails and the back stay,
The feature is that these members are integrated by welding.

According to a third aspect of the present invention, there is provided a motorcycle body frame, wherein the rear arm bracket has an engine suspension boss portion and a footrest bracket mounting boss portion.

[0009]

According to the first aspect of the invention, the truss main frame and the rear arm bracket are separate bodies, and the truss main frame supports members from the front fork to the seat, and does not require a down tube. Therefore, the size of the main frame in the height direction can be reduced, and welding and painting can be performed between the trusses, which improves workability.

Further, by disposing the truss main frame, the hot air above the engine can be discharged to the outside of the vehicle body, and the influence of heat on the fuel supply system such as the carburetor and the intake system such as the air cleaner can be reduced, and the output can be obtained. It is effective for improvement.

According to the second aspect of the present invention, the truss main frame is integrated by welding a plurality of pipe members, and the truss main frame supporting the members from the front fork to the seat can be easily and firmly formed. .

According to the third aspect of the invention, the engine suspension boss portion and the footrest bracket mounting boss portion can be easily provided integrally with the rear arm bracket.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The body frame of a motorcycle according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is a side view of a motorcycle, FIG. 2 is a side view of a vehicle body frame with an engine and a rear arm removed, and FIG. 3 is a side view of a vehicle body frame.
Is a plan view of the main frame, FIG. 5 is a side view of the rear arm bracket, and FIG. 6 is a rear view of the rear arm bracket.

The body frame 1 of the motorcycle has a truss main frame 4 for supporting members from the front fork 2 to the seat 3 and a rear arm bracket 6 for supporting a rear arm 5. Truss mainframe 4
A front fork 2 is provided on the front side head pipe 7, a front wheel 8 is supported on the lower portion of the front fork 2, and a handle 9 is attached on the upper portion. A fuel tank 10 is arranged in front of the truss main frame 4, and a tandem seat is arranged as a seat 3 behind the fuel tank 10. The tandem seat is composed of a tandem front seat 3a and a tandem rear seat 3b.

A rear cowl 11 covers the lower part of the seat 3 from the both sides to the rear. A front cowl 12 covers the side of the head pipe 3 and the front side of the upper portion of the front fork 2.

A rear arm 5 is supported on the rear arm bracket 6 via a pivot shaft 13 so as to be vertically swingable, and a rear wheel 14 is provided on the rear arm 5.

An engine 15 is supported on the truss main frame 4 and the rear arm bracket 6, and the engine 15 has two parallel cylinders. The cylinder 16 of the engine 15 is arranged so as to be tilted to the front side, and the cylinder 16 is attached to and supported by the truss main frame 4.
The upper part of the crankcase 17 is supported by the truss main frame 4 via the mounting bracket 18, and the rear part of the crankcase 17 is mounted and supported by the rear arm bracket 6. That is, the suspension of the engine 15 is configured by the truss main frame 4 and the rear arm bracket 6, and the engine 15 is also used as a part of the strength member, so that the down tube descending from the vicinity of the head pipe toward the front of the engine is prevented. It has a configuration that is not necessary.

An intake pipe 1 is provided on the rear side of each cylinder 16.
9, the carburetor 20 is connected to the intake pipe 19, and the intake pipe 19 and the carburetor 20 are connected to the truss member frame 4
It is located between The carburetor 20 has an air cleaner 21.
Are connected, and the air cleaner 21 is disposed below the fuel tank 10. A fuel cock 22 is provided below the fuel tank 10, and fuel is supplied to the carburetor 20 by operating the fuel cock 22, and the fuel cock 22 is located between the truss frames 4. An oil tank 23 is arranged above the crankcase 17, and an oil supply port (not shown) of the oil tank 23 is located on the right side between the truss frame frames 4.

An exhaust pipe 24 is provided in front of each cylinder 16.
The exhaust pipe 24 extends below the engine 15 and extends rearward, and the muffler 25 is connected to the rear end of the exhaust pipe 24. The muffler 25 is located above the rear wheel 14 on both left and right sides.

The body frame 1 includes a truss main frame 4 for supporting members from a front fork 2 to a seat 3 which are formed by welding a plurality of pipe members in a truss shape,
The rear arm bracket 6 is made of a light metal material such as aluminum or aluminum alloy, and the upper part of the rear arm bracket 6 is connected to the lower center of the truss main frame 4 in the front-rear direction by a fastening member 26.

The truss main frame 4 includes a head pipe 7, a pair of left and right upper and lower tank rails 27 and 28, members 29 to 31 connecting the pair of left and right upper and lower tank rails 27 and 28, and cross tubes 33 to 35, and a left and right pair. The seat rail 36 and the back stay 37, and the cross members 38 to 40 connecting the pair of left and right seat rails 36 and the back stay 37 are integrated, and these members are integrated by welding. A reinforcement frame 41 is provided between the cross tube 33 and the head pipe 7, and a choke knob 43 is attached to a bracket 42 attached to the reinforcement frame 41. A stay 44 is welded to the rear of the lower tank rail 28, and the mounting bracket 18 is tightened and fixed to the stay 44 by mounting bolts 45.

The crankcase 17 of the engine 15 is suspended by the mounting bracket 18, and the cylinder 16 of the engine 15 is suspended by the boss portion 46 at the substantially central portion of the lower tank rail 28. Reference numeral 32 constitutes a rear portion of the lower tank rail 28 on the right side, and is displaced upward from a member constituting the rear portion of the lower tank rail 28 on the left side to serve as an escape for the clutch housing formed by a part of the crankcase 17. There is.

A connecting frame portion 47 is welded to a rear end portion of the upper tank rail 27, a back stay 37 is welded to the connecting frame portion 47, and a left and right pair is provided between the connecting frame portion 47 and the left and right seat rails 36. Auxiliary frame 4
8 is welded. A standing handle pipe 49 is welded to the back stay 37, and an auxiliary pipe 50 is provided between the standing handle pipe 49 and the back stay 37.
A luggage hook 51 is provided on the.

A mounting stay 52 is provided at the center of the back stay 37, and a mounting bracket 53 for supporting the muffler 25 is tightened and fixed by a mounting bolt 54.

When viewed from the side, the upper and lower tank rails 27, 28 are located between the connecting point A between the seat rail 36 and the upper tank rail 27, and the connecting point B between the rear arm bracket 6.
Also, the standing handle pipe 49 is connected to the back stay 37 in front of the connection point C between the seat rail 36 and the back stay 37 when viewed from the side, and is connected again at the rear end of the back stay 37. Therefore, the truss main frame 4 always has a pair of upper and lower sides when viewed from the side, and has high rigidity.

When viewed from the side, the back stay 37 is bent and rises at a substantially central portion and further bent and extends rearward so as to match the stepped shape of the tandem front seat 3a and the tandem rear seat 3b. It has a different structure. Therefore, the seat rail 36 is bent and the tandem seat 3
Compared to the structure of the support part b, the bending degree of the pipe can be reduced and the molding is facilitated. Also, the standing handle pipe 49 has a smaller diameter than the back stay 37, the front side is connected and supported by the auxiliary pipe 50, the load is mainly supported by the back stay 37, and the standing handle pipe 49 is supported by the back stay 37. It supports the shortage. The standing handle pipe 49 serves as a grip for standing and is also used for loading.

The left and right side portions 60 of the rear arm bracket 6 are formed by forging of an aluminum material, and the upper and lower connecting portions 61, 62 for connecting the left and right side portions 60 are formed by casting of an aluminum material and integrated by welding. Has been done. The left and right side portions 60 are formed by forging an aluminum material because strength is required, and the upper and lower connecting portions 61, 62 are formed.
Since is required to have a complicated shape, it is formed by casting an aluminum material, and a manufacturing method according to the function is used.

Engine suspension boss portions 60a, 6 for supporting the crankcase 17 of the engine 15 on both left and right side portions 60.
0b and footrest bracket mounting boss portions 60c and 60d for mounting the footrest bracket 70 are integrally formed, and the rear arm bracket 6 can easily be provided integrally with the engine suspension boss portions 60a and 60b and the footrest bracket mounting boss portions 60c and 60d. it can.

A shaft hole 60e for supporting the pivot shaft 13 is formed in the central portion of the left and right side portions 60. Further, a stepped portion 60f is formed on the upper portion of each of the left and right side portions 60, and the connecting frame portion 47 welded to the rear end portions of the upper and lower tank rails 27 and 28 is applied from the outside to the stepped portion 60f. The mounting bolts as the fastening members 26 are screwed into the mounting holes 60g formed at the two positions to connect at two positions on the extension line in the longitudinal direction of the tank rail.

At the upper connecting portion 61 and the lower connecting portion 62 of the rear arm bracket 6, the upper end mounting portion 61a of the rear cushion 71 and the mounting portion 62a of the rear suspension link 72 are mounted.
Are integrally formed.

As described above, the truss main frame 4 and the rear arm bracket 6 are separate bodies, and the truss main frame 4 supports the members from the front fork 2 to the seat 3. The workability can be improved because the size can be reduced, the handleability during welding and painting can be improved, and the jig can be downsized.

Further, the truss main frame 4 is integrated by welding a plurality of pipe members, and the front fork 2
The truss main frame 4 supporting the members from the seat to the seat 3 can be easily and firmly formed.

Further, the arrangement of the truss main frame 4 allows the traveling wind to pass through between the pipes, so that the hot air above the engine 15 can be discharged to the outside of the vehicle body, and the fuel supply system such as the carburetor 20 and the air cleaner can be discharged. It is effective for improving the output by reducing the influence of heat on the intake system.

[0034]

As described above, the invention according to claim 1 is
Since the truss main frame and the rear arm bracket are separate bodies, and the truss main frame supports the members from the front fork to the seat, the dimension of the main frame in the height direction can be made small, so that it can be used for welding or painting. The workability can be improved by improving the ease of handling and reducing the size of the jig.

Further, by disposing the truss main frame constructed by welding a plurality of pipe members in a truss shape, the hot air above the engine can be discharged to the outside of the vehicle body.
The effect of heat on the fuel supply system such as the carburetor and the intake system such as the air cleaner is reduced, and it is effective in improving the output.

In the invention according to claim 2, the truss main frame is integrated by welding a plurality of pipe members,
The truss main frame supporting the members from the front fork to the seat can be easily and firmly formed.

According to the third aspect of the invention, the engine suspension boss portion and the footrest bracket mounting boss portion can be easily provided integrally on the rear arm bracket, and the engine suspension and the footrest bracket mounting structure can be simplified.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle.

FIG. 2 is a side view of a vehicle body frame from which an engine, a rear arm and the like are removed.

FIG. 3 is a side view of a body frame.

FIG. 4 is a plan view of a main frame.

FIG. 5 is a side view of a rear arm bracket.

FIG. 6 is a rear view of the rear arm bracket.

[Explanation of symbols]

 1 Body Frame 2 Front Fork 3 Seat 4 Truss Main Frame 5 Rear Arm 6 Rear Arm Bracket 26 Fastening Member

Claims (3)

[Claims] 1. A truss main frame for supporting members from a front fork to a seat formed by welding a plurality of pipe members in a truss shape, and a rear arm bracket for supporting a rear arm made of a light metal material, A vehicle body frame of a motorcycle, wherein an upper part of a rear arm bracket is connected to a lower center of the truss main frame in the front-rear direction by a fastening member. 2. The truss main frame comprises a head pipe, a pair of left and right upper and lower tank rails, a member connecting between the pair of left and right upper and lower tank rails, a pair of left and right seat rails and a back stay, and a pair of left and right seat rails thereof. It has a cross tube that connects the back stays,
The vehicle body frame according to claim 1, wherein these members are integrated by welding. 3. The vehicle body frame for a motorcycle according to claim 1, wherein the rear arm bracket has an engine suspension boss portion and a footrest bracket mounting boss portion.