JPH11286292A - Body frame for scooter type motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a body frame for scooter type motorcycle capable of enhancing the rigidity of the footrest part of a body frame further more. SOLUTION: In a body frame 2 for a scooter type motorcycle having a low floor footrest part between a steering handle and a seat, a main frame 11 connected to a head pipe 3 for supporting the steering handle is extended backward obliquely to the lower part from the head pipe 3 and further extended backward substantially horizontally, and a laterally extending cross pipe 15 is connected to the rear extended end of the main frame 11. The front ends of right and left side frames 14 are connected to the right and left end parts of the cross pipe 15, the side frames 14 are extended backward obliquely to the upper part, and the rear ends of right and left sub-frames 12 are connected to the connecting parts of the side frames 14 to the cross pipe 15. The sub-frames 12 are extended forward substantially horizontally and further extended forward obliquely to the upper part, and the front ends of the sub-frames 12 are connected to the head pipe 3.

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 conventionally connected to a head pipe, and the main frame is extended by being inclined obliquely rearward and downward, and a lower end of the inclined portion is substantially formed. There is one that is bent horizontally to extend rearward, and the lower extension forms a low-floor footrest.

In the body frame of the scooter-type motorcycle, since a large bending moment acts on the footrest on the low floor due to its structure, it is necessary to increase the rigidity of the footrest. In the conventional body frame, in order to increase the rigidity of the footrest, the front ends of a pair of left and right side frames are connected near the rear bent portion of the main frame, and the side frames are extended substantially horizontally rearward. Further, a structure is adopted in which the rear end of the main frame and the left and right side frames are connected by a cross pipe.

[0004]

In the case of a small scooter-type motorcycle, the required rigidity of the footrest portion can be ensured by the above-mentioned conventional body frame, but in the case of a larger scooter-type motorcycle, Since the distance between the front and rear wheels (wheel base) is increased, a greater bending moment is applied to the footrest portion, and the load itself is increased by two passengers, further improvement in frame rigidity is required. Is done.

An object of the present invention is to provide a scooter-type motorcycle body frame capable of further increasing the rigidity of a footrest portion of the body frame.

[0006]

SUMMARY 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, the head pipe supporting the steering wheel. The connected main frame extends obliquely downward and rearward from the head pipe, further extends substantially horizontally rearward, and connects a cross pipe extending left and right to the rear extension end of the main frame, and connects the left and right ends of the cross pipe. Connecting the front ends of the left and right side frames and extending the side frames obliquely rearward and upward, connecting the rear ends of the left and right subframes to the connection between the side frames and the cross pipe, The frame extends substantially horizontally forward and further obliquely upward and forward, and the front end of the sub-frame is connected to the head pipe.

[0007]

According to the scooter type motorcycle body frame according to the present invention, the rear ends of the left and right sub-frames are connected to the connecting portion between the cross pipe and the side frame connected to the rear extending end of the main frame. And the sub-frame is extended substantially horizontally forward, and further extended diagonally forward and connected to the head pipe, so that the footrest portion of the frame of the present invention has a main frame extending from the head pipe and a head pipe similarly. There are two sets of closed cross-section structures in plan view that connect the left and right subframes extending from the left and right subframes with a cross pipe, so that the rigidity of the footrest portion can be improved.

[0008]

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.

In 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 body frame 2 so as to be vertically swingable. 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 vehicle body frame 2 includes one main frame 11 and two left and right subframes 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 part 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 extending obliquely upward and rearward 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.

The inclined portion 1 of the 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 of the present embodiment, the head pipe 3 is a monocoque head gusset 10 made of sheet metal.
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.

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.

Further, in the present 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, so that the front ends of the side gussets 13 are provided. , 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 11 Main frame 11d Rear extension end of main frame 12 Subframe 12a Front end of subframe 12d Rear end of subframe 14 Side frame 14a Front end of side frame 15 Cross pipe

Claims (1)

[Claims] 1. A scooter-type motorcycle body frame having a low-floor footrest portion between a steering handle and a seat, wherein a main frame connected to a head pipe supporting the steering handle is connected to a head pipe. The main pipe extends from left to right, and the left and right ends of the cross pipe are connected to the front ends of the left and right side frames. And extend the side frame obliquely rearward and upward, connect the rear ends of the left and right sub-frames to the connection between the side frame and the cross pipe, and extend the sub-frame substantially horizontally forward. A scooter-type motorcycle body frame extending further obliquely upward and forward and connecting a front end of the sub-frame to the head pipe.