JPH0413194B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a body structure of a scooter type motorcycle (including a tricycle with one front wheel and two rear wheels) having a low step floor.

(Prior Art) Scooter-type motorcycles having a low step floor have been known for a long time, and the body structure of this motorcycle is as shown in Japanese Utility Model Publication No. 37-28303, in which a body cover is attached to the body. A monochrome frame that also serves as a frame, or JP-A-57-
As shown in Japanese Patent No. 11772, a vehicle body frame is generally constructed of metal pipes and a resin cover is attached to the vehicle body frame.

(Problems to be Solved by the Invention) Particularly in the case of today's scooter-type motorcycles, the body structure shown in the above-mentioned Japanese Patent Application Laid-Open No. 57-114772 is lightweight and has a small displacement. It has become mainstream because of its excellent power performance.

Furthermore, recently, scooter-type motorcycles with large displacement and high output capable of running at high speeds have been developed. In such scooter-type motorcycles, large stress tends to act particularly on the portion of the vehicle body structure where a low step floor is provided. Therefore, if the thickness of the vehicle body frame itself is increased in order to withstand such stress, the weight of the vehicle body itself will increase, which will hinder the improvement of power performance.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a low-slung step floor having a predetermined width between the front and rear wheels, and suspends from the rear and lower part of the head tube in the center of the floor. A main frame is arranged so as to extend rearward, with the lower end of a straight down tube connected to its front end, and the main frame has a box-like cross-sectional shape, and an inner plate fixed to an outer plate constituting the main frame. A cross member is supported through the inner and outer plates in the width direction.

(Example) Examples of the present invention will be described below based on the accompanying drawings.

Fig. 2 is a side view of a scooter type motorcycle adopting the frame structure according to the present invention with the cover removed; Fig. 3 is a plan view of the same state;
The figure is a side view of the motorcycle with the cover attached, and FIG. 5 is a plan view of the same state.

First, let me explain the overall structure of the vehicle body frame.
The down tube 1 is a straight metal pipe without bending, and the lower end of the head tube 2 is welded to the upper end of the down tube 1 through a reinforcing plate 3. A steering stem is inserted into the head tube 2, a handle 4 is fixed to the upper end of the steering stem, and a front fork 5 is fixed to the lower end. An arm 6 is swingably attached to the lower end of the front fork 5, and the front end of the arm 6 rotatably supports the front wheel 7. Furthermore, between the middle part of the arm 6 and the upper end of the front fork 5, a Cushion 8 is being erected.

On the other hand, the front end of the main frame 9 is welded to the lower end of the down tube 1. A patch 10 is provided at this welded portion to ensure a sufficient weld bead and to strengthen it. The main frame has a front half 9a extending horizontally rearward from the lower end of the down tube 1, and further extending obliquely upward and rearward to form a rear half 9b. This rear part 9b has a cross plate 1 equipped with a mounting stay for the fuel tank 12.
In addition to 1a, cross plates 11b and 11c are installed laterally, a fuel tank 12 is placed on the cross plates 11a and 11b, a seat 12a is placed on this fuel tank, and a pivot shaft 13 is attached.
A swing type power unit 14 is swingably supported on this pivot shaft 13 via a link. This swing type power unit 14 is comprised of a case 16 housing an engine 15 and a power transmission mechanism, and drives a rear wheel 17 supported at the rear end of the case 16. In addition, the rear end of the case 16 and the main frame 9
A rear cushion 18 is installed between the rear parts 9b.

Next is the fourth section regarding covers that cover the vehicle body frame.
This will be explained based on the drawings and FIG.

The covers are made of resin molded by injection molding or the like, and a low step floor 19 is provided to cover the front half 9a of the main frame 9, and a leg shield 20 is integrated from the front end of the low step floor 19. Standing up, this Legshield 20
A front cover 21 that covers the front fork 5 and front cushion 8 above the front wheel 7
Further, below the seat 12a, the outside of the rear half 9b of the main frame 9 is covered with a side cover 22, and the side cover 22 and the low step floor 19 are integrally continuous.

Next, the structure of the front half 9a of the main frame 9 will be explained based on FIGS. 1 and 6. Here the first
The figure is a cross-sectional view taken along the line A--A in FIG. 4, and FIG. 6 is a cross-sectional view taken along the line B--B in FIG.

The front half 9a of the main frame 9 has a box-like cross section, and has a double structure part 25 on both sides formed of an inner plate 23 and an outer plate 24 made of steel plates, and this double structure part 25 has a box shape in cross section. It has a vertical box shape,
This double structure portion 25 is extended rearward as it is to constitute the rear half portion 9b of the main frame 9. The front half 9a of the main frame 9 is also closed with a lower plate 27 made of steel plate, and these upper plate 26 and lower plate 27 connect the left and right double structure parts 25, 25,
Furthermore, the front end opening of the main frame front half 9a is closed by a partition panel, and the rear end opening is closed by a partition panel 28. Here, the outer plates are 24, 26, and 27.

In addition, the inner plate 23 is attached to the main frame front half 9a.
and a cross pipe 29 and a cross bar 30a, which are cross members supported through the outer plate 24,
30b is provided to increase the rigidity, and the base end of a brake pedal 31 is pivotally connected to the cross pipe 29 as shown in FIG. 2, and brackets 32 are welded to both ends of the cross bar 30a. The step floor 19 made of resin is attached to the step floor 32 using bolts 33. The upper surface of the floorboard 34 is attached to the lower surface of both sides of this step floor 19, and the steel plate floorboard 3
4 and the lower plate 27 is closed with a floor under cover 35 made of resin.

Furthermore, a recess 36 is formed in a part of the upper plate 26 as shown in FIG. 1, and the battery 3 is inserted into this recess 36.
It stores 7.

(Effects of the Invention) As explained above, according to the present invention, the main frame forming a part of the body frame of a low-floor motorcycle is not composed of a metal pipe having a bent portion as in the past, but is made of a pressed steel plate or the like. The jointed box-shaped structure is connected to the lower end of the straight downtube, and a cross member that also has other functions is passed through the main frame in the width direction to support it. Stress is not concentrated at the lower end, and lateral and torsional rigidity are significantly improved. Even with large displacement and high output, the body rigidity is sufficient, and the power performance is improved without increasing the weight of the body frame. You can improve your skills.

Furthermore, according to the embodiment, if a recess is formed in a part of the upper plate that constitutes the front half of the main frame, and the battery is stored in this recess, it is not only advantageous in terms of space, but also makes it easier to concentrate heavy objects at the rear of the scooter. type of motorcycle, it is possible to maintain a good weight balance. Furthermore, the upper surface of the floorboard is overlapped and joined to the lower surface of both sides of the step floor, and the upper surface of the floorboard is overlapped and joined to the lower surface of the front half of the main frame. Providing a floor undercover has many effects such as improving water resistance.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view taken along the line A-A in Fig. 4, Fig. 2 is a side view of a low-floor motorcycle to which the frame structure according to the present invention is applied, with covers removed, and Fig. 3 is the same state. 4 is a side view of the low-floor motorcycle with covers attached, FIG. 5 is a plan view of the same state, and FIG. 6 is a sectional view taken along line B-B in FIG. 2. . In the drawings, 1 is a down tube, 2 is a head tube, 9 is a main frame, 9a is the first half of the main frame, 9b is the second half of the main frame, 14
19 is a swing type power unit, 19 is a step floor, 23 is an inner plate, 24 is an outer plate, 25 is a double structure part, 26 is an upper plate, 27 is a lower plate, and 29 and 30 are cross members.

Claims (1)

[Claims] 1. A low step floor with a predetermined width is provided between the front and rear wheels, and a main frame is connected to the front end of a straight down tube that hangs down from the rear of the down tube in the center of the floor. The main frame has a box-like cross-sectional shape, and is provided with an inner plate that is fixed to the outer plate constituting the main frame, and the cross member is supported through the inner plate and the outer plate in the width direction. A scooter-type motorcycle body structure featuring: