JPH0784191B2 - Motorcycle frame - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body frame of a motorcycle having a low floor type footrest portion located between front and rear wheels.

Prior Art Motorcycles with low-floor footrests (eg scooters)
In, a relatively large diameter steel pipe, a steel plate press-formed product,
Alternatively, by combining them to form a low-floor frame material and disposing it as a single member on the center line of the vehicle body, the weight of the vehicle body and the manufacturing cost have been reduced.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, when the front-rear wheel distance of a motorcycle having a low-floor footrest is increased, when the vehicle body frame structure is adopted, the frame material of the low-floor part is increased. The diameter must be reduced and the weight of the vehicle body becomes excessive.

Means for Solving Problems and Actions and Effects The present invention relates to improvement of a motorcycle body frame that overcomes such difficulties, and in a motorcycle having a low floor type footrest portion located between front and rear wheels, A main vehicle body frame that extends downward toward the rear of the vehicle body by forming a low floor by curving backward to the head pipe and curving backward under the head pipe,
Left and right two lower main frames and one upper main frame separated from each other in the form of being located at the vertices of a triangle, and the upper main frame, left and right lower main frames, and left and right lower main frames, At the position near the curved portion,
The three rigid members are connected to each other, and the tip portions of the upper and lower main frames are assembled to each other and connected to the head pipe, and the front portion of the upper and lower main frames is connected to the rigid member. Is configured in a substantially triangular pyramid shape.

Since the present invention is configured as described above, the curved portions of the main frame that are most likely to be deformed by the bending load and the torsional load applied to the main frame are two lower left and right lower main frames and one upper main frame. Reinforced by three rigid members that connect the three main frames of the frame to each other.
The bending and torsional rigidity of the main body frame, which is stiffened and consists of the three main frames, is significantly increased, and the front-rear length of the low floor portion is increased while suppressing an increase in the weight of the main body frame. Can be made larger.

Further, in the present invention, the front end portions of the upper and lower main frames are assembled together and connected to the head pipe, and the front portion of the upper and lower main frames from the connection point with the rigid member is formed into a substantially triangular pyramid shape. Since the main frame has a truss structure having high strength and rigidity, the main body frame consisting of the upper and lower frames of the three main frames is greatly deformed to the head pipe. It is possible to reliably transmit without causing the above, and from this point as well, the weight reduction of the vehicle body can be promoted.

Further, according to the present invention, the fuel tank which is conventionally arranged just below the seat can be arranged in the space defined by the two left and right lower main frames and the one upper main frame. Since the torsional moment acting on the low floor portion can be greatly reduced due to the above, it is not necessary to increase the diameter of each main frame more than necessary, and in this respect as well, the weight can be reduced.

EXAMPLE An example of the present invention shown in FIGS. 1 to 6 will be described below.

FIG. 1 is a schematic left side view showing a motorcycle 10 having a low-floor footrest A, and FIG. 2 is a plan view of relevant parts.

The steel pipe body frame of the motorcycle 10 has a head pipe 12 that rotatably supports a handle rotation shaft 11 that carries a front wheel FW at its lower end, and a head pipe 12 that extends downward to the pipe 12 and curves rearward therebelow. The main body frame 14 extending in the rearward direction of the vehicle body is formed as a main member, and the main body frame 14 is separated from each other in the form of being located at the apexes of a triangle as shown in FIG. , Right lower two main frames 16 and one upper main frame 18. The upper main frame 18 is located on the center line of the vehicle body, and the left and right lower main frames 16 are connected to the rising portions 17 thereof.
The rear end of the upper main frame 18 is welded to the horizontal connecting frame 20 which is connected to each other at. In addition, in each of the front and rear of the low-floor footrest A, each main frame
16, 16 and 18 are connected to each other and triangular steel plates 22 and 24 are welded and fixed to the front of the triangular steel plate 22, and the upper main frame 18
And a reinforcing frame 19A that connects the left and right lower main frames 16 respectively, and a reinforcing frame 19B that penetrates the left and right lower main frames 16 and connects the two to each other.

Further, a U-shaped seat support frame 26 is welded in a horizontal posture to the rising portion 17 of the lower main frame 16, and a pair of reinforcing members 28 for supporting the seat support frame 26 in the left and right are welded in an inclined posture. The two-seater seat S is placed on the rear ends of the seat support frame 26 and the lower main frame 16.

Further, a support shaft 32 is attached to a pair of reinforcing plates 30 welded and fixed to the rising portions 17 of the left and right lower main frames 16, and the support shaft 32 is attached.
A power unit 36 is tiltably supported on the output shaft of the power unit 36 via a pair of links 34.
RW and muffler (muffler) 38 are supported,
The left shock absorber 40 is provided between the horizontal connecting frame 16A connecting the left and right lower main frames 16 at the rear end and the power unit 36.
The right shock absorber 42 is interposed between the horizontal connection frame 16A and the muffler 38.

The fuel tank 50 is located in a space surrounded by the front and rear triangular steel plates 22 and 24 and the main frames 16, 16 and 18, and connects the left and right lower main frames 16 to each other. The pair of front and rear screws 48 are fixed to the groove type horizontal members 44 and 46 welded to the lower main frame 16.

The vehicle body cover 52 of the motorcycle 10 has a hat-shaped cross section and covers the fuel tank 50 and the main vehicle body frame 14 from above at the low-floor footrest A, as shown in FIG. The right portion is formed as a footrest plate 54, and the footrest plate 54 portion is screwed and fixed to a member on the vehicle body frame side at two points B and C at the front and rear.

This fixed relationship is shown in FIGS. 3, 5, and 6. That is, the left and right lower main frames 16 penetrate through the reinforcing frame 19B, both ends of which project outward, and the projecting pieces 25 projecting from both sides of the triangular steel plate 24, the front side of the vehicle body is loose. An assembly composed of a vehicle body cover support pipe 64 that is a U-shaped bent pipe that is formed to rise at an inclination, and connecting plates 66 and 68 that maintain the distance between the vehicle body cover support pipe 64 is fixed using screws. The footrest plate 54 is fixed to the assembly. And on this footrest plate 54,
In the vicinity of the triangular steel plate 24, a passenger's footrest projection 55 is provided so as to project.

In addition, a lid 56 that covers the inlet 51 of the fuel tank 50 so that it can be opened and closed.
Is attached to the window formed on the vehicle body cover 52 via the hinge 58, and when it is closed or more, it is locked by the lock 60 attached to the free end thereof. ing.

The present embodiment is configured as described above, and the front-rear length of the main vehicle body frame 14 in the low-floor footrest A is increased in correspondence with the lengthened front and rear axle distances. ,
The main body frame 14 is formed by the lower main frames 16 and 16 and the upper main frame 18 that define a large triangular space, and each main frame 16, 16 and 18 is formed of triangular steel plates 22 and 24 and reinforcing frames 19A and 19B. The structure of the low-floor footrest portion A connected by means has sufficiently high bending rigidity and torsional rigidity, and can effectively counter large bending moment and torsional moment acting on the vehicle body frame during traveling.

Moreover, by disposing the heavy fuel tank 50 between the main frames 18, 18, 16 in the low-floor footrest A, rather than directly under the seat, the inertial force of the fuel tank 50 is caused during traveling. Since the torsional moment acting on the main body frame 14 is significantly reduced, it is not necessary to increase the diameter of each of the main frames 18, 18, 16 more than necessary. It is possible to obtain a rigid body frame.

Further, by arranging the fuel tank 50, which is conventionally arranged just below the seat, between the lower frames, it is possible to lower the center of gravity of the vehicle body, but at the same time, the seat S is arranged at a lower position without being restricted by the fuel tank 50. Therefore, the position of the center of gravity of the occupant is lowered, and the torsional moment acting on the main vehicle body frame 14 due to the weight of the occupant during traveling is also reduced. 16,16,18
It is possible to reduce the diameter and reduce the weight accordingly.

Further, since the fuel tank 50 is surrounded by the lower main frames 16, 16 and the upper main frame 18, it is hard to receive an external force,
And the triangular steel plate 24 located at the rear is the power unit.
It also functions as a heat shield for 36.

Since there is no fuel tank immediately below the seat S, the space can be used as a space for storing equipment such as a battery or a space for storing small items.

[Brief description of drawings]

FIG. 1 is a schematic left side view of a motorcycle adopting a vehicle body frame according to an embodiment of the present invention, FIG. 2 is a plan view of a main part thereof, and FIG. 3 is an enlarged right side view of a main part of the motorcycle, Fourth
Figures 5, 5 and 6 are IV-IV in Figure 3, respectively.
FIG. 6 is a schematic cross-sectional view of a line, a VV line, and a VI-VI line. 10 …… motorcycle, 11 …… steering wheel rotating shaft, 12 …… head pipe, 14 …… main body frame, 16 …… lower main frame, 17 …… rising part, 18 …… upper main frame, 20 …… sideways Connection frame, 22 …… Triangle steel plate, 24 …… Triangle steel plate,
25 …… Projection piece, 26 …… Seat support frame, 28 …… Reinforcement material,
30 ... Reinforcement plate, 32 ... Shaft, 34 ... Link, 36 ... Power unit, 38 ... Exhaust pipe, 40 ... Left shock absorber, 42
...... Right side shock absorber, 44 …… Grooved horizontal material, 46 …… Grooved horizontal material, 48 …… Screw, 50 …… Fuel tank, 51 …… Injection port, 52
…… Vehicle cover, 54 …… Foot rest plate, 55 …… Vehicle footrest projection for passengers, 56 …… Lid, 60 …… Locking device, 62 …… Protrusions, 64 ……
Body cover support pipe, 66 …… connecting plate, 68 …… connecting plate,
S ... seat.

Claims (1)

[Claims] 1. A motorcycle having a low-floor footrest portion located between front and rear wheels, wherein the low-floor portion is formed by being directed downward to the head pipe and being curved rearward therebelow, The main body frame extending toward the rear of the vehicle body is formed by two lower main frames, one lower main frame and one upper main frame, which are separated from each other in the form of being located at the apexes of a triangle, and the upper main frame and the left and right main frames. The lower main frames and the left and right lower main frames are connected to each other by three rigid members in the vicinity of the curved portion, and the tip portions of the upper main frames are assembled to each other to the head pipe. A vehicle body frame for a motorcycle, wherein the front and front portions of the upper and lower main frames, which are connected to each other, are connected to the rigid member in a substantially triangular pyramid shape.