JPH085117Y2 - Motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial field of application The present invention relates to a vehicle body structure of a motorcycle.

BACKGROUND ART A conventional motorcycle is a facility for suspending front wheels and rear wheels on a main body frame, and for mounting an engine, a power transmission device, an occupant, and luggage on the body frame,
It is configured to hold equipment and the like.

Therefore, various forces such as reaction forces from the front and rear wheels, the weight of heavy objects such as the engine and the fuel tank, or the weight of occupants and luggage act on the vehicle body frame. Since they act on different parts of the frame, uneven stress is likely to occur in the body frame, and the rigidity of the entire body frame must be increased, which tends to increase the weight of the vehicle body.

Means and Actions for Solving the Problems The present invention has been made in view of such circumstances, and a motorcycle according to the present invention has a pair of left and right main parts having a square cross-section and having a front end fixed to a head pipe and extending rearward. A frame; center pillars each having an intermediate portion fixed to a rear end portion of the main frame and extending substantially vertically; a pair of left and right seat rails fixed to an upper end portion of the center pillar and extending rearward; and the center pillar The center pillar includes a back stay provided between the seat rail, a rear fork pivotally attached to a lower portion of the center pillar, and an engine attached to a lower end of the center pillar. , The lower part that is integrally formed vertically and that supports the rear fork and the engine has a wide width to support the seat rail. The width of the upper portion is narrower than that of the lower portion. Further, each center pillar is connected to the head pipe only through the corresponding main frame, and the engine is connected to the main frame and the center pillar. Only supported by and.

According to the present invention, since the seat rail, the back stay, the rear fork and the engine are attached to one center pillar, the load due to the occupant, luggage, the load from the rear wheels and the load due to the engine are concentrated on the center pillar. Not only is the body frame effectively stress-resistant without uneven distribution of stress in the body frame, but also the frame constituent members are reduced, and the overall body frame can be a lightweight frame for its rigidity.

Of the above loads applied to the center pillar, the load from the rear wheel via the rear fork and the load due to the engine weight are particularly large, but the center pillar widens the lower part to which these large loads are applied to increase the rigidity of the part. Since it is made large, the load can be satisfactorily carried. Moreover, since the upper portion is formed narrow, the weight increase of the center pillar can be avoided and the weight of the vehicle body can be reduced.

Further, since the center pillar is integrally formed vertically, it is possible to obtain sufficient rigidity to receive various loads and to contribute to the reduction of the constituent members of the vehicle body frame and the number of assembling steps.

Since the center pillar is connected to the head pipe only via the main frame, it becomes a body frame with a simple structure centering on the center pillar as a whole, and the engine is the only member connecting the head pipe and the center pillar. Since it is supported only by a certain main frame and the center pillar, an effective space is generated around the center pillar and around the engine, particularly in front of and below the engine, and the degree of freedom in design is significantly improved.

Embodiments The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a side view of a motorcycle to which the present invention is applied. The motorcycle body frame includes a head pipe 1 and a pair of left and right rectangular cross-sections having a front end fixed to the head pipe 1 and extending obliquely downward to the rear. Mainframe 2 (see Figure 2)
A center pillar 3 fixed to the rear end of each main frame 2 and extending substantially in the vertical direction; an intermediate fixed to the upper end of the center pillar 3; and a front end fixed to the intermediate part of the main frame 2. A pair of left and right seat rails 4 extending rearward, and a back stay 5 provided between the center pillar 3 and the seat rail 4. A front fork 6 is pivotally attached to the head pipe 1 via a steering mechanism, and front wheels 7 are supported on the front fork 6. A rear fork 8 is pivotally attached to the lower part of the center pillar 3 so as to be swingable.
A rear wheel 9 is supported on the. A rear cushion 10 is provided between the vehicle body frame and the rear fork 8.

An engine 11 is mounted below the main frame 2, and the lower rear portion of the engine 11 is attached to the lower end portion of the center pillar 3 and the upper front portion thereof is an engine hanger.
It is attached to the main frame 2 via 12 and is supported only by the main frame 2 and the center pillar 3 as shown, and the engine 11 itself is also a strength member of the vehicle body frame. The illustrated engine 11 is a V-shaped engine, and includes a cylinder 13 arranged substantially vertically and a cylinder 13a arranged substantially longitudinally. A carburetor 14 is arranged at the upper rear part thereof, is opened toward the front and the lower side, and a radiator 15 is arranged at the front.

A fuel tank 16 is placed above the main frame 2 to the seat rail 4. The fuel tank 16 is spanned between the pair of left and right main frames 2 and seat rails 4, so that the upper side of the engine 11 is covered by the bottom surface of the fuel tank 16. In addition,
An intermediate portion in the width direction of the bottom surface projects between the left and right main frames 2 and seat rails 4 as shown by 16a and 16b in the figure.

The reaction force from the rear wheels 9, unillustrated seats provided on the fuel tank 16 and the seat rail 4, the occupant from the luggage stand, the weight of the luggage, and the weight of the engine 11 are mainly caused by the center pillar 3. Since it can be received in a concentrated manner, an unbalanced load such as twisting the frame does not act on the body frame. Therefore, the body frame as a whole has sufficient rigidity as a skeleton of a motorcycle and has a small number of constituent members. So it is lightweight.

Since the center pillar 3 that receives the various loads intensively is integrally formed in the upper and lower parts, it has sufficient rigidity to receive these loads.

As shown in FIG. 1, the lower portion of the center pillar 3 to which the rear fork 8 and the engine 11 are attached has a wide front-rear width and is sufficient to carry the load from the rear wheel 9 and the engine 11. The upper portion connected to the seat rail 4 is provided with rigidity and has a narrow width to reduce the weight of the center pillar 3 as a whole.

A wind guide plate 17 is provided in the upper central portion of the radiator 15 so as to guide the traveling wind from the front beyond the upper portion of the radiator 15 to the rear thereof, and the front end portion of the wind guide plate 17 has a head. It is supported by the rear end of the cowling 18 covering the front of the pipe 1. As shown in FIG. 2, the baffle plate 17 is formed in a groove shape by a bottom plate 19 and side plates 20 erected along both side edges of the bottom plate 19 so that the front part is low and wide. , As much traveling wind as possible on the radiator
It is designed to get over 15 and be guided to the rear.
The bottom plate 19 extends rearward from the radiator 15 substantially along the upper surface of the engine 11, and serves as a partition wall 22 that partitions the engine portion from the upper portion of the vehicle body. An appropriate hole is provided in the rear portion of the partition wall 22, and the carburetor 14 projects above the partition wall 22 through the hole and is cooled by the traveling wind.

As described above, according to the present invention, various loads acting on the body frame can be centrally received by the integral center pillar having sufficient rigidity to receive these loads. Almost no biased load such as twisting acts. Therefore, it is possible to obtain a vehicle body frame having sufficient rigidity with a simple structure and reduce the weight of the vehicle body frame. In addition, an effective space is created around the center pillar and the engine, which significantly improves the degree of freedom in design.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle to which the present invention is applied, and FIG. 2 is a plan view showing a planar arrangement of a body frame member together with a carburetor cooling passage member. 1 ... Head pipe, 2 ... Main frame, 3 ... Center pillar, 4 ... Seat rail, 5 ... Back stay, 6 ... Front fork, 7 ... Front wheel, 8 ... Rear fork, 9 ... Rear wheel, 10 …… rear cushion, 11 ……
Engine, 12 …… Engine hanger, 13 …… Cylinder,
14 …… Carburetor, 15 …… Ragetor, 16 …… Fuel tank, 17 …… Baffle plate, 18 …… Cowling, 19 …… Bottom plate, 20
…… Side plate, 21 …… Air passage, 22 …… Partition wall.

 ─────────────────────────────────────────────────── --- Continued from the front page (56) Reference JP 59-53291 (JP, A) JP 59-145675 (JP, A) JP 59-223581 (JP, A) JP 61- 125975 (JP, A) JP 59-134072 (JP, A) JP 59-156878 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A pair of left and right main frames each having a rectangular cross section and having a front end fixed to a head pipe, and center pillars each having an intermediate portion fixed to a rear end of each main frame and extending substantially vertically. A pair of left and right seat rails fixed to the upper end of the center pillar and extending rearward;
A back stay provided between the center pillar and the seat rail; a rear fork pivotably attached to a lower portion of the center pillar; and an engine attached to a lower end of the center pillar, The center pillar is
The lower pillar supporting the rear fork and the engine is formed to have a wide width and the upper rail supporting the seat rail is formed to have a width narrower than that of the lower portion. A motorcycle, characterized in that it is connected to the head pipe only through the respective main frames, and the engine is supported only by these main frames and the center pillar.