JPH11286291A - Body frame for scooter type motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a body frame for scooter type motorcycle capable of reducing the weight of a body frame and extending the freedom in the design of the inclination of a main frame. SOLUTION: In a body frame for a scooter type motorcycle having a low floor footrest part between a steering handle and a seat, the front end opening 10b of a head gusset 10 consisting of a sheet metal-made square pole with a vertically long cross section having front and rear end openings 10b, 10c is welded and fixed to a head pipe 3 for supporting the steering handle, the front end of a main frame 11 is welded and fixed to the rear end opening 10c of the head gusset 10, and the front ends of lateral sub-frames 12 are welded and fixed to the lateral side surfaces of the head gusset 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scooter-type motorcycle body frame having a low-floor footrest between a steering wheel and a seat.

[0002]

2. Description of the Related Art Conventionally, as a body frame of a scooter-type motorcycle, one main frame is directly welded and connected to a head pipe, and the main frame is extended obliquely downward rearward and further extended substantially horizontally rearward. In some cases, a low-floor footrest is formed by the rear extension.

In the scooter-type motorcycle body frame, since a large bending moment acts on the connection between the head pipe and the main frame, it is necessary to increase the rigidity of the connection.

In the conventional body frame, the main frame is directly connected to the head pipe by welding in order to increase the rigidity of the connection portion, and the connection portion has a size that extends over both the head pipe and the main frame. A structure is adopted in which a pair of left and right, or a pair of upper and lower reinforcing plates are arranged, and the reinforcing plates are welded to the head pipe and the main frame.

[0005]

Recently, however, there has been a strong demand for not only starter-type motorcycles but also lighter vehicles in order to improve fuel efficiency. However, in the above conventional body frame, in order to secure rigidity, not only the head pipe but also the main frame adopts a considerably thick pipe member,
In addition, since a structure is adopted in which the connecting portion of both is covered with a reinforcing plate, the weight of the connecting portion is particularly large, and this point is a bottleneck in reducing the weight of the vehicle body frame.

Further, the above-mentioned conventional body frame is premised on that the main frame is directly welded and connected to the head pipe, so that there is a problem in that the degree of freedom in designing the inclination angle and the like of the main frame is low. That is, if the inclination angle of the main frame is too steep, it becomes difficult to weld the main frame to the head pipe. To ensure weldability while steepening the main frame, it is necessary to bend the upper end of the main frame so that it is almost perpendicular to the head pipe, but bend the thick main frame with a small curvature. It is difficult to do so, resulting in a low degree of freedom in design.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and can reduce the weight of a vehicle body frame.
It is another object of the present invention to provide a body frame of a scooter-type motorcycle that can increase a degree of freedom in design such as an inclination angle of a main frame.

[0008]

According to a first aspect of the present invention, there is provided a scooter-type motorcycle body frame having a low-floor footrest between a steering wheel and a seat. A front end opening of a rectangular tube-shaped head gusset having a front and a rear end opening made of sheet metal and having a front and rear end opening is welded and fixed to the head pipe to be welded, and the front end of the main frame is welded and fixed to the rear end opening of the head gusset The head gusset is characterized in that the front ends of the left and right subframes are fixedly welded to the left and right sides of the head gusset.

According to a second aspect of the present invention, there is provided a scooter-type motorcycle body frame provided with a low-floor footrest between a steering handle and a seat, wherein a main frame is attached to a head pipe which supports the steering handle. And extend the main frame obliquely downward and rearward from the head pipe, further extend substantially horizontally rearward, and connect left and right sub-frames to the head pipe, and extend the sub-frame obliquely downward and rearward from the head pipe. The left and right sub-frames having different diameters from the sub-frames are connected to the rear ends of the left and right sub-frames through cylindrical side gussets. The right gussets are connected to each other via a cross pipe, and an engine suspension bracket is connected to a connection between the cross pipe and the gusset.

[0010]

According to the scooter type motorcycle body frame according to the first aspect of the present invention, the front end opening of a sheet metal square tubular head gusset is fixedly welded to the head pipe, and the rear end of the head gusset is fixed. Since the front end of the main frame is fitted and inserted into the opening and fixed by welding, the thick and heavy main frame can be generally shortened by the length of the head gusset, and the body frame can be lightened accordingly.

The head gusset is vertically long in a transverse section, that is, vertically long in the direction (vertical direction) of the bending moment acting on the connecting portion between the head pipe and the main frame. There is an effect that the required rigidity can be easily and surely secured at the connecting portion between the head pipe and the main frame where a large bending moment acts.

In addition, since the main frame is connected to the head pipe via the head gusset, the design freedom such as the inclination angle of the main frame can be improved as compared with the conventional structure in which the main frame is directly connected to the head pipe. There is an effect that the degree can be improved.

That is, in the case of a conventional structure in which the main frame or the like is directly connected to the head pipe, if the inclination angle is steep, it becomes difficult to weld the main frame to the head pipe. It is necessary to sharply bend the vicinity of the upper end of the main frame so as to be almost perpendicular to the head pipe. On the other hand, in the present invention, such a sharp bend is not required since the head gusset is interposed, and thus the degree of freedom in design is high.

Furthermore, since the main frame and the like are joined to the head pipe via the head gusset, the required welding length can be reduced, and the productivity can be improved. That is, when the main frame or the like is directly joined to the head pipe, a reinforcing plate is indispensable from the viewpoint of securing rigidity, and as a result, a required welding length becomes long.

According to the second aspect of the present invention, the front ends of the left and right side frames are welded to the rear ends of the left and right subframes via the side gussets. By setting the diameter appropriately, there is an effect that the sub-frame and the side frame having different diameters can be easily and reliably welded and connected.

Further, the left and right side gussets are welded to each other via a cross pipe, the rear end of the main frame is welded to the cross pipe, and an engine suspension is connected to a connection between the cross pipe and the side gusset. Since the brackets are connected by welding, there is an effect that the support rigidity of the engine unit can be improved.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 8 are diagrams for explaining a body frame of a scooter type motorcycle according to a first embodiment of the present invention, and FIG. 1 is a left side view of the scooter type motorcycle provided with the body frame of the embodiment, Figures 2 and 3
FIG. 4 is a left side view and a plan view of the vehicle body frame, FIG. 4 is a left side view around the head gusset, FIG.
FIG. 6 is a left side view around the side gusset, and FIG. 7 is a VI of FIG.
FIG. 8 is a sectional view taken along the line I-VII, and FIG.

Referring to FIG. 1, reference numeral 1 denotes a scooter type motorcycle, which pivotally supports a front fork 4 to be steerable left and right by a head pipe 3 at a front end of a body frame 2 and a front wheel 5 at a lower end of the front fork 4. And a steering handle 6 is fixed to the upper end, and an engine unit 7 is pivotally supported at a substantially central portion in the front-rear direction of the vehicle body frame 2 so as to be vertically swingable, and a rear wheel 8 is provided at a rear end of the engine unit 7. And has a schematic structure in which a seat 9 is mounted on the upper part of the body frame 2. The front fork 4 and the body frame 2 are surrounded by a body cover 22, and a low-floor footrest F is formed between the seat 9 and the steering handle 6. Reference numeral 9a denotes a backrest of a front occupant, 9b denotes a backrest of a rear occupant, and 9c denotes a gripping member for stabilizing the riding posture of the rear occupant.

The body frame 2 includes one main frame 11 and two left and right sub-frames 1 welded to the head pipe 3 via a head gusset 10.
2 and 12 and left and right side frames 14 and 14 which are welded to the rear ends of the left and right subframes 12 and 12 via side gussets 13 and 13, respectively.

The head gusset 10 is formed by welding and connecting left and right plates 10a, 10a press-formed in a U-shape in cross section and having front and rear end openings 10b, 10c in a vertically long rectangular cross section. It is monocoque. The left and right side plates 10a are connected to each other via a reinforcing plate 23 disposed inside. The reinforcing plate 23 has a U-shaped cross section, and one side 23a is welded to the inner surface of the right side plate 10a,
The other side 23b is welded to the periphery of the slit 10e of the left side plate 10a from outside.

The front end opening 10b of the head gusset 10
Has a shape along the outer peripheral shape of the head pipe 3, and is welded by fitting the peripheral edge of the front end opening 10 b to the outer peripheral surface of the head pipe 3.

The rear end opening 10c of the head gusset 10
Has a shape corresponding to the shape of the front end 11a of the main frame 11, and the front end 11a is fitted and inserted into the rear end opening 10c and welded. The main frame 11 includes a lower inclined portion 11b extending obliquely downward and rearward from a rear end opening 10c of the head gusset 10, and a horizontal portion (rear extension portion) 11c extending substantially horizontally rearward from a lower end of the lower inclined portion 11b. Have been.

The upper end of the sub-frame 12 is crushed to form a flange, and the front end 12a is welded to a portion of the outer surface of the side plate 10a of the head gusset 10 facing the reinforcing plate 23. The sub frame 12 includes an inclined portion 12b extending obliquely downward and rearward from the side plate 10a of the head gusset 10, and a horizontal portion (rear extension) 12c extending substantially horizontally rearward from the lower end of the inclined portion 12b.

The inclined portion 1 of the left and right sub-frames 12
2b and 12b are steeper than the inclined part 11b of the main frame 11, and the two left and right inclined parts 12b and 1b are inclined.
A radiator 24 is provided between the spaces 2b and in the space on the front side of the lower inclined portion 11b of the central main frame 11. Reference numeral 24a denotes a blower fan, which is located in a triangular space formed by the inclined portions 12b and 11b when viewed from the side.

The left and right side gussets 13, 1
Reference numeral 3 denotes a so-called monocoque rectangular cylinder in which an outer plate 13a and an inner plate 13b, each of which has a substantially U-shaped cross-section and a substantially L-shape in side view, are joined by welding. The rear end 12d of the sub-frame 12 is fitted and inserted into the front end opening 13c of the side gusset 13 and connected by welding, and the front end 14a of the side frame 14 is fitted and inserted into the rear end opening 13d. Welded connection.

The left and right side frames 14 are provided with rising portions (upwardly inclined portions) 14b which extend obliquely rearward and upward from rear end openings 13d of the side gussets 13.
And a horizontal portion 14c extending substantially horizontally rearward from the upper end of the rising portion 14b.

The left and right side gussets 13 are welded to each other by a cross pipe 15. This cross pipe 15 has a circular cross-sectional shape,
The right end portion 15b is fitted and inserted into the connection hole of the inner plate 13a of the side gusset 13 and fixed by welding. Further, the side gusset 13 and the left and right end portions 15b of the cross pipe 15 are connected via the reinforcing member 15a. Fixed by welding. In addition, 25 is a bracket for attaching the side stand.

The height of the horizontal portions 12c, 12c of the left and right sub-frames 12 and the horizontal portion 11c of the central main frame 11 are set so that the lower surfaces thereof substantially coincide with each other. The rear end 11d is formed in accordance with the size of the cross pipe 15, and is welded to the center of the cross pipe 15 in the vehicle width direction.

The left and right side gussets 13, 1
3 and the left and right ends 15b of the cross pipe 15
The left and right engine suspension brackets 16, 16 are fixed by welding so as to extend over the lower surface of the engine. The pivot portions 7a of the engine unit 7 are pivotally supported by the engine suspension brackets 16,16.

The lower inclined portion 11b of the one main frame 11 and the two left and right side frames 14,
And the right and left rising portions 14b, 14b are welded to each other by tension pipes 17, 17. Front end portions 17a, 17a of the tension pipes 17, 17
Is fixed to the common front bracket 18 by welding, and the front bracket 18 is attached to the inclined portion 11 b of the main frame 11.
It is fixed by welding to the middle part of. The rear ends 17b, 17b of the left and right tension pipes 17, 17 are fixed to the rear brackets 19, 19 by welding, respectively, and the rear bracket 19 is fixed to the rising portion 14b by welding.

The left and right tension pipes 1
A gate-shaped sheet stay 20 made of sheet metal is bridged and welded to 7 and 17. A hinge bracket 21 is provided on the upper surface of the seat stay 20 at the center in the vehicle width direction, and the hinge bracket 21 supports a hinge fixed to the front end of the seat 9.

Slope 1 of left and right sub-frames 12
A foot bracket 12e is fixedly welded to the 2b and the horizontal portion 12c, and the foot bracket 12e supports the foot board portion 22b of the vehicle body cover 22.

The left and right side frames 14, 1
The front and rear substantially central portions of the horizontal portions 14c and 14c are welded to each other by a cross pipe 29, and the rear ends of the horizontal portions 14c support the rear end of the sheet 9. At the same time, it is welded and joined by a gate-shaped sheet receiving bracket 30 provided with a lock mechanism.

Further, the left and right horizontal portions 14c, 1
A standing handle 31 is disposed substantially in parallel with the horizontal portion 14c in a plan view at the rear of 4c. The standing handle 31 is inserted through a hole formed in the side cover portion 22a that covers the lower portion of the seat of the vehicle body cover 22, grasped and pulled up, and the vehicle stands upright on the main stand.

The horizontal portions 14c, 14b extend from between the rising portions 14b, 14b of the left and right side frames 14, 14.
c, a fuel tank 26 is mounted, and the horizontal portion 14
A storage box 27 capable of storing a helmet H and the like is mounted on the rear portion between the storage box 27 and the fuel tank 26, and a battery 28 is mounted between the storage box 27 and the fuel tank 26. The storage box 27 includes a bolt hole 31b formed in the vehicle body mounting flange portion 31a of the standing handle 31, and the seat receiving bracket 3
0 is fixed to the body frame using bolt holes 30b formed in the upper side 30a.

In the vehicle body frame 2 according to the present embodiment, the head pipe 3 is made of sheet metal and is a monocoque head gusset 10.
The front end opening 10d of the head gusset 10 is fixed by welding.
The front end 11a of the main frame is fixedly welded to the rear end opening 10e, and the left and right plates 10a,
10b, the front end 12 of the left and right sub-frames 12, 12
Since the main frames 11a and 11a are fixed by welding, the thick main frame 11 having a large thickness can be generally shortened by the length of the head gusset 10, and the weight can be reduced accordingly.

The head gusset 10 is vertically long when viewed in a transverse section, that is, the head pipe 3 and the main frame 1
1 is vertically elongated with respect to the direction (vertical direction) of the bending moment acting on the connection portion, and the section modulus in that direction is increased, so that the head pipe and the main frame on which the largest bending moment acts on the body frame 2 Rigidity required for the connection with the shaft can be easily and reliably secured. In the present embodiment, the reinforcing plate 23 is disposed in the head gusset 10 and fixed by welding.
10a is not deformed inward, and rigidity can be secured from this point as well.

In this embodiment, the main frame 11
And the sub-frame 12 is joined to the head pipe 3 via the head gusset 10, so that the inclination angle of the main frame and the sub-frame is smaller than the conventional structure in which the main frame and the sub-frame are directly joined to the head pipe. High degree of freedom. That is, in the case of a structure in which the main frame or the like is directly joined to the conventional head pipe, the steeper the inclination angle, the more difficult it is to join the head pipe, or a problem of interference with the radiator or the like is likely to occur. . In the case of the present embodiment, a steeper inclination angle of the main frame can be realized without any trouble by appropriately setting the shape of the head gusset.

Further, since the main frame 11 and the sub-frame 12 are joined to the head pipe 3 via the head gusset 10, the required welding length can be shortened and the productivity is improved. That is, when the main frame and the sub-frame are directly joined to the head pipe, a reinforcing plate is indispensable from the viewpoint of securing rigidity, and as a result, a required welding length becomes long.

Furthermore, in this embodiment, the front ends 14a of the left and right side frames 14 are welded to the rear ends 12d of the left and right subframes 12 via the side gussets 13. , Rear end opening 13
By appropriately setting the diameters of b and 13c, the sub-frame 12 and the side frame 14 having different diameters can be easily welded and joined.

The left and right side gussets 13, 13
The two were welded to each other via a cross pipe 15, the rear end 11d of the main frame 11 was welded to the cross pipe 15, and an engine suspension bracket was welded to a connection between the cross pipe 15 and the side gusset 13. Therefore, the support rigidity of the engine unit 7 can be increased.

The middle of the lower inclined portion 11b of the main frame 11 and the middle of the rising portions 14b, 14b of the left and right side frames 14, 14 are welded and joined by a pair of left and right tension pipes 17, 17. Since the left and right tension pipes 17, 17 are joined by the seat stay 20, the rigidity of the entire body frame 2 can be greatly increased, and the sense of twisting of the body can be reduced.

[Brief description of the drawings]

FIG. 1 is a left side view of a scooter type motorcycle including a vehicle body frame according to an embodiment of the present invention.

FIG. 2 is a left side view of the side of the vehicle body frame.

FIG. 3 is a plan view of the vehicle body frame.

FIG. 4 is a left side view of a head gusset portion of the vehicle body frame.

5 is a sectional rear view (a sectional view taken along line VV in FIG. 4) of a head gusset portion of the vehicle body frame.

FIG. 6 is a left side view of a side gusset portion of the vehicle body frame.

7 is a cross-sectional rear view (a cross-sectional view taken along line VII-VII of FIG. 6) of a side gusset and a cross pipe portion of the vehicle body frame.

FIG. 8 is a plan view of a connection portion of a main frame, a sub frame, a side frame, and a cross pipe of the vehicle body frame.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Scooter type motorcycle 2 Body frame 3 Head pipe 6 Steering handle 9 Seat 10 Head gusset 10a, 10a Left and right side plates (left and right side surfaces) 10b Front end opening 10c Rear end opening 11 Main frame 11a Front end of main frame 12 Sub frame 12a Front end of sub frame 13 Side gusset 14 Side frame 15 Cross pipe 16 Bracket for engine suspension

Claims (2)

[Claims] 1. A scooter-type motorcycle body frame having a low-floor footrest between a steering handle and a seat, wherein a front pipe and a rear end made of sheet metal are provided on a head pipe that supports the steering handle. A front end opening of a rectangular tube-shaped head gusset having a longitudinal section having an opening is welded and fixed, and a front end of a main frame is welded and fixed to a rear end opening of the head gusset, and left and right sides of the left and right sides of the head gusset. A body frame for a scooter-type motorcycle, wherein a front end of the sub-frame is welded and fixed. 2. A scooter-type motorcycle body frame having a low-floor footrest between a steering handle and a seat, wherein a main frame is connected to a head pipe that supports the steering handle. Extend the frame obliquely downward and backward from the head pipe, further extend substantially horizontally backward, connect the left and right sub-frames to the head pipe, extend the sub-frame obliquely downward and backward from the head pipe,
Further, the left and right side frames having different diameters from the sub frame are connected to the rear ends of the left and right sub frames via cylindrical side gussets.
A vehicle frame for a scooter-type motorcycle, wherein right side gussets are connected to each other via a cross pipe, and an engine suspension bracket is connected to a connection portion between the cross pipe and the gusset.