JPH04278892A - Frame structure of motorcycle - Google Patents

Abstract

PURPOSE:To reduce the weight of motorcycle frame. CONSTITUTION:As for the frame structure of a motorcycle which forms a frame body by assembling the left and right frames 2 and 3, a head pipe 4 is formed integrally with one frame 2, and a vacant part 44 which communicates to the frames 2 and 3 is installed on the head pipe 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the frame structure of a motorcycle, and more particularly to the structure of a head pipe and a frame extending from the head pipe.

0002

2. Description of the Related Art Generally, a die-cast frame body is constructed by dividing a head pipe into left and right parts, which are connected to each other by bolts.

0003

[Problem to be Solved] Therefore, when the left and right half-split head pipes are assembled, misalignment occurs, resulting in poor workability. Furthermore, the head pipes 01 usually form a complete cylindrical shape when combined, and are heavy, which is an obstacle to reducing the weight of the frame. The present invention has been devised in view of the above, and an object thereof is to provide a lightweight frame structure with excellent assembly workability.

0004

[Means and operations for solving the problems] In order to achieve the above object, the present invention provides a frame structure for a motorcycle in which a pair of left and right frames are assembled to form a frame body, in which a head pipe is integrated into one frame. The frame structure of the motorcycle is such that the head pipe is formed with a hollow part that communicates with the frame.

Since the head pipe is integrally formed on one of the frames, there is no misalignment of the head pipe, and workability during assembly is excellent. Furthermore, since the head pipe is provided with a hollow portion that communicates with the frame, the head pipe becomes lighter and the weight of the frame can be reduced.

[0006]

[Embodiment] An embodiment of the present invention illustrated in FIGS. 1 to 12 will be described below. This embodiment is an example applied to a folding motorcycle 1, and FIG. 1 shows an overall side view of the folding motorcycle 1 when assembled, and FIG. 2 shows an entire side view when folded.

The folding motorcycle 1 includes a pair of left and right front frames 2 that support a steering system including a front wheel FW;
3. The vehicle body frame includes a pair of left and right rear frames 18 and 19 that support the drive system including the rear wheels RW. The front frames 2 and 3 each include a left and right pair of elongated plate-like members in the front and rear, and a head pipe 4 is provided between the front ends thereof.

A lower steering shaft 5 extends through the head pipe 4 and is rotatably held therein. An upper steering shaft 6 is pivotally connected to the upper end of the lower steering shaft 5.
A front fork 8 is fixed to the lower part of the vehicle via a bottom bridge 7, and a front wheel FW is pivotally supported by the front fork 8.

The upper steering shaft 6 is rotatably held by the upper arm 9, and a handle holder 10 is pivotally connected to the upper end of the upper steering shaft 6. A pair of left and right handlebars 11 are foldably assembled by the handle holder 10. There is. A headlight cover 12 is provided to cover the head pipe 4, and a headlight 13 is fixed to the front opening of the headlight cover 12.

A pair of brackets 14 are erected on the left and right sides of the head pipe 4, and the upper arm 9 is pivotally supported at the upper end of the brackets 14 by a pin 16. Note that the pin 16 is coaxial with the connecting support shaft between the lower steering shaft 5 and the upper steering shaft 6 when the vehicle is running straight.

A pair of brackets 15 are also provided on the front portions of the left and right front frames 2 to protrude upward.
A lock pin 17 slidably attached to the rearwardly extending portion of the upper arm 9 is fitted into the circular hole bored in the bracket 15 during assembly. further extends rearward and diagonally downward.

On the other hand, the rear frames 18 and 19 are composed of a pair of left and right plate members that support the engine 20 and the rear wheels RW, etc., with a fuel tank 21 and an oil tank 22 disposed between the upper halves thereof, and a central portion of the rear frames 18 and 19. An exhaust muffler 23 is disposed obliquely between them. The rear wheel RW is pivotally supported by the ends of rear frames 18 and 19 that extend diagonally downward to the rear, and the engine 20 is mounted on the rear frame 18 between the front wheel FW and the rear wheel RW.
, 19.

A pair of front and rear rollers 25 and 26 are pivotally supported on the outer surfaces of the upper sides of the rear frames 18 and 19, respectively.
The guide rail grooves 24, which are provided on the inner surface of the front frame 2 and oriented in the front-rear direction, fit into and roll into contact with each other, allowing the front frames 2 and 3 to move back and forth with respect to the rear frames 18 and 19. ing. A joint arm 27 connects the rear end of the upper arm 9 and the front ends of the rear frames 18 and 19 by pivotally connecting both ends thereof.

A seat 32 is supported above the rear part of the front frame 2 so as to be movable up and down via front and rear links 30 and 31 consisting of a pair of left and right legs.

The links 30 and 31 are pivotally supported on the lower surface of the seat 32, the lower ends of the left and right legs of the front link 30 are supported by a support shaft 33 at the rear of the upper sides of the rear frames 18 and 19, and the rear link 31 is When the lower ends of the left and right legs are supported by the support shafts 34 at the rear ends of the front frames 2 and 3, and the front frames 2 and 3 are in a position moved forward relative to the rear frames 18 and 19 during assembly (Fig. 1) The lower ends of the front and rear links 30, 31 are contracted, and both links 30, 31 are made to stand up, fixing the seat 32 at a high position. Conversely, when folded, the lower ends of the links 30 and 31 widen, and the sheet 3
2 is lowered to a lower position.

The general structure of the folding motorcycle 1 is as described above, and when assembled with the front frames 2 and 3 moved forward with respect to the rear frames 18 and 19, the lower steering shaft 5, The upper steering shaft 6 and the handle holder 10 are coaxially connected in a straight line, and the seat 32 is in a high position so that the vehicle can travel.

Then, when the lock pin 17 is removed and the front frames 2 and 3 are moved rearward relative to the rear frames 18 and 19, the upper arm 9 is attached to the pin 1 as shown in FIG.
The seat 32 is folded rearward around the center point 6 and falls horizontally together with the handle holder 10, and the seat 32 is lowered and stored in a low position. When the handlebar 11 is folded, it becomes the folded state shown in FIG. 2, which reduces the longitudinal length of the vehicle body and lowers the vehicle height, resulting in a compact shape that is convenient for transportation.

[0018] In such a folding motorcycle 1,
The structures of the front frames 2, 3 and head pipe 4 will be explained in detail below.

The left front frame 2 is manufactured integrally with the head pipe 4 at its front end by die casting.
Its shape is illustrated in FIGS. 3 to 8. The left front frame 2 has its upper and lower edges bent inwardly, its front and rear edges also bent inwardly, and the guide rail groove 24 is formed by a protrusion running longitudinally therethrough. Note that flat openings 28 and 29 are integrally formed at the front and rear positions of the side surface of the frame, and can be used as a grip.

A cylindrical connecting portion 2a is provided at the rear of the front frame 2 and protrudes inward.
It is now connected to At the front end of the left front frame 2, a bent edge slightly extends inward, and a head pipe 4 is integrally formed with the extended portion 2b.

The head pipe 4 has a pair of annular portions 40 at the top and bottom.
, 41 are formed coaxially with the oblique central axis C-C, and both the annular parts 40 and 41 are connected by the front wall 42 and the rear wall 43, leaving the left and right cavities 44, and the front and rear walls 42, 4
3 extends slightly to the right in parallel, and an upper wall 45 and a lower wall 46 are constructed in parallel above and below between the extending portions, and a mating surface 47 having a rectangular opening is formed on the right side ( Figure 7
reference).

The upper wall 45 also extends to the left so as to be penetrated by the upper annular portion 40, and the pair of left and right brackets 14 are erected upward at both left and right ends of the upper wall 45. As shown in FIG. 7, two female screw holes 48 and 49 are provided in the mating surface 46 of the portion extending to the right from the head pipe 4.

On the other hand, the right front frame 3 is formed approximately symmetrically with the left front frame 2 except for the head pipe 4, as shown in FIGS. opening 28
, 29 are formed in symmetrical positions to serve as grips, and the rear part has a cylindrical connecting part 3a that protrudes inward.
is provided, and at the front end, the side wall and the upper and lower walls are bent to the left, passing through a slight extension 3b, and a flat rectangular opening 5 is formed at the edge thereof.
0 is formed, and the left side of the opening 50 is the mating surface 51.
It becomes. The opening 50 is provided with bolt holes 52 and 53 at the top and bottom, respectively.

Therefore, the left and right front frames 2 and 3
When put together, as shown in FIGS. 11 and 12, the cylindrical connecting parts 2a and 3a are connected to each other in the rear part and joined by bolts 54, and the front part is connected to the right side of the head pipe 4 formed integrally with the left front frame 2. Front and rear walls 42 extending to
43. The mating surface 51 of the front rectangular opening 50 of the right front frame 3 contacts the mating surface 47 having a rectangular opening formed by the upper and lower walls 45 and 46 with both rectangular openings aligned, and the bolt hole on the right Bolts 55 and 56 are passed through the holes 52 and 53 and screwed into the female screw holes 48 and 49 on the left side, respectively, to secure them together.

As described above, the left and right front frames 2,
3 is easy to assemble and has excellent workability. Since the head pipe 4 has a cavity 44 on the left and right sides and communicates with the left and right front frames 2 and 3, it is extremely light and the weight of the frame can be reduced. Note that the cavity 44 communicates with the insides of the left and right front frames 2 and 3;
, 3 are shielded from the outside to prevent foreign matter from entering.

In the above embodiment, the front frame 2,
3 and the head pipe 4 formed integrally with the front frame 2 were manufactured by pressurized die-casting.
Ordinary gravity mold casting G. D. C. It is also possible to manufacture by

[0027]

According to the present invention, the head pipe formed integrally with one of the frames is provided with a hollow portion communicating with the frame, so that the weight of the frame can be reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall side view of a folding motorcycle according to an embodiment of the present invention when assembled.

FIG. 2 is an overall side view of the same when folded.

FIG. 3 is a side view of the left front frame and head pipe.

FIG. 4 is a plan view of the same.

FIG. 5 is a view taken along the V arrow in FIG. 3;

FIG. 6 is a view taken along the VI arrow in FIG. 3;

FIG. 7 is a view taken along arrow VII in FIG. 4;

FIG. 8 is a sectional view taken along the line VIII-VIII in FIG. 5;

FIG. 9 is a side view of the right front frame.

FIG. 10 is a plan view of the same.

FIG. 11 is a plan view showing a state in which the left front frame and head pipe are assembled with the right front frame.

12 is a sectional view taken along the line XII-XII in FIG. 11. FIG.

[Explanation of symbols]

1...Folding motorcycle, 2, 3...Front frame, 4...Head pipe, 5...Lower steering shaft,
6...Upper steering shaft, 7...Bottom bridge, 8...Front fork, 9...Upper arm, 10...
Handle holder, 11... Handlebar, 12... Headlight cover, 13... Headlight, 14, 15... Bracket, 16... Pin, 17... Lock pin, 18, 19...
Rear frame, 20...engine, 21...fuel tank, 2
2... Oil tank, 23... Exhaust muffler, 24... Guide rail groove, 25, 26... Roller, 27... Jont arm,
28, 29... Opening, 30, 31... Link, 32... Sheet, 33, 34... Support shaft, 40, 41... Annular portion, 42... Front and rear walls, 43... Rear wall, 44... Cavity, 45... Top wall , 46... Lower wall, 47... Matching surface, 48, 49... Female screw hole, 50... Opening, 51... Matching surface, 52, 53... Bolt hole, 54,
55, 56... Bolt, 58, 59... Opening.

Claims (1)

[Claims] [Claim 1] In a motorcycle frame structure in which a pair of left and right frames are assembled to form a frame body, a head pipe is integrally formed in one of the frames, and a hollow portion communicating with the frame is provided in the head pipe. A motorcycle frame structure characterized by: