JP2529633B2 - Motorcycle frame - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle body frame of a motorcycle.

[0002]

2. Description of the Related Art Conventionally, as a vehicle body frame of a motorcycle, a double cradle type frame and a semi-double cradle type frame shaped like an engine mounted on a cradle have been widely used because of their relatively high strength and rigidity. In motorcycles, the height of the body above the ground,
In other words, the minimum ground clearance must be secured by a certain amount, but in the case of the double cradle type frame and the semi-double cradle type frame, there is a down tube under the engine, so the minimum ground clearance must be taken accordingly. May be difficult to design. Also, in order to downsize the entire vehicle body, there is a demand to shorten the wheel base, but if there is a down tube, it is necessary to prevent the down tube from coming into contact with the steering wheel. It was difficult to shorten.

[0003]

Recently, in order to emphasize the frame itself as an exterior design, there is a demand for exposing the frame to both outer side surfaces of the vehicle body. In response to this request, assuming a structure in which the frame itself is exposed on both outer side surfaces of the vehicle body, the pair of frames must be bendable in the lateral direction. The present invention solves the above-mentioned drawbacks of the prior art and meets the above-mentioned demand,
In a motorcycle body frame, it is lightweight and has high strength, vertical rigidity and torsional rigidity, thus ensuring a minimum ground clearance, shortening the wheel base, and bending the frame laterally without impairing aesthetics. It is an object to make this easy in design.

[0004]

In order to solve the above-mentioned problems, in a motorcycle body frame of the present invention, a pair of left and right tank rails connected to a head pipe are rearward and side views from the head pipe. The tank rails are arranged so as to extend in a substantially straight line downwardly and are exposed so as to be exposed on both outer side surfaces of the vehicle body, and a vertically long flat pipe made of aluminum extruded material is used as the tank rails. An inclined surface is formed, and the tank rail has a cross-sectional shape.
The length in the vertical direction exceeds three times the horizontal length of the tank rail.

[0005]

1 to 4, reference numeral 1 denotes a steering head pipe, on which a front fork 3 to which a front wheel steering 2 is attached is rotatably held. Reference numeral 4 denotes a steering wheel for the driver to operate the front fork 3, and 5 denotes a pair of left and right tank rails connected to the head pipe 1.
Is formed in a curved shape so as to extend substantially linearly rearward and obliquely downward and to have a bulge when viewed from the upper surface.
The pair of tank rails 5 and 5 uses a flat pipe 14 made of a vertically elongated flat aluminum extruded material, and is arranged so as to be exposed on both outer side surfaces of the vehicle body. Reference numeral 6 denotes a bracket rear arm, which is welded and fixed to the rear ends of the pair of tank rails 5 and 5 by a welded portion 6a. 7 is a rear arm pivotally connected to the bracket rear arm 6 by an axis 8.
A rear wheel 9 is supported at the rear end of the rear arm 7. 10 is a radiator, 11 is an engine, and these are suspended below a pair of tank rails 5, 5. A seat rail 12 and a back stay 13 are fixed to the pair of tank rails 5 and 5 and the bracket rear arm 6 by bolting or the like.

A vertically long flat pipe made of the aluminum extruded material
A cross section of the tank rail 5 consisting of 14 is shown in FIG.
As shown in FIG. 4, the flat pipe 14 is formed by a continuous outer wall o, an upper side wall u, an inner side wall i, and a lower side wall d into a vertically long flat pipe shape, and an inclined surface is formed on the upper surface of the outer side wall o.
15 is formed. Inside the flat pipe 14, an outer wall o and an inner wall i are formed.
Upper and lower reinforcing ribs 5a and 5b having surfaces orthogonal to and are formed. The reinforcing ribs 5a and 5b are continuous in the longitudinal direction of the flat pipe 14, and the thickness of the outer side surface o located on the outer side surface of the vehicle body is larger (thicker) than the inner side surface i located on the inner side surface of the vehicle body. ), The rigidity of the outer side surface o is increased. In addition, the presence of the inclined surface 15 serves as an escape for the rider's knees and the like, and the width of the rider's legs is reduced.

Inside the flat pipe 14, the walls of the flat pipe 14 and the upper and lower reinforcing ribs 5a, 5b form three sections X, Y, Z each having a vertically long cross section and a substantially hollow rectangular shape. The outer side wall o (the surface is an inclined surface 15), the upper side wall u, the inner side wall i, and the reinforcing rib 5a, and the hollow section Y includes the outer side wall o, the reinforcing rib 5a, the inner side wall i, and the reinforcing rib 5b. The hollow section Z is composed of an outer wall o, a reinforcing rib 5b, an inner side wall i, and a lower side wall d. 3 sections X,
Since all the cross-sectional shapes of Y and Z are vertically long and are substantially hollow rectangles, the flat pipe 14 has a length in the vertical direction exceeding three times the length in the horizontal direction. In the embodiment of FIG. 4, the tank rail 5 is used as an example.
Has a height of 140 mm, lateral (left and right) width of 30 mm, outer wall o has a wall thickness of 2.5 to 3.5 mm, inner wall i has a wall thickness of 2 mm, and reinforcing ribs 5a, 5b and other wall thicknesses are about 2 mm. Is. Thus, the tank rail 5 has a length in the vertical direction considerably larger than a length in the horizontal direction, so that the rigidity in the vertical direction is extremely large and the tank rail 5 is easily bent in the horizontal direction. In the drawings, a drive mechanism for transmitting the drive output of the engine 11 to the rear wheels 9, a fuel tank held by a pair of tank rails 5, 5, and a seat rail.
Illustrations of seats, etc., on which the driver is held, which are held in 12, etc., are omitted.

As described above, the cross-sectional shape of each of the three internal compartments is vertically long and approximately hollow rectangular, and the pair of left and right flat pipes 14 made of aluminum extruded material which is vertically long as a whole is used as the tank rails 5 and 5. Therefore, the rigidity and the torsional rigidity in the vertical direction with the head pipe 1 as a fulcrum are increased, and it has sufficient strength and rigidity without using the down tube unlike the conventional double cradle type frame and semi-double cradle type frame. Become. And
A body frame is composed of a pair of left and right tank rails 5, 5, a bracket rear arm 6 and a rear arm 7, and unlike the prior art, it is not necessary to provide a down tube below the engine 11, so the minimum ground clearance above the ground is designed. It can be easily and sufficiently secured, and the front wheel steering 2 may be largely offset to the rear side, so that it is extremely easy to shorten the wheel base.

Since the vertically long tank rails 5 and 5 are exposed on both outer side surfaces of the vehicle body, the frame can be emphasized in terms of external design, and the reinforcing ribs 5a and 5b are extruded inside the tank rails 5 and 5. At the same time, it is integrally molded, and the internal three sections have a vertical cross section with a substantially hollow rectangular shape, and the combination of the three sections has a vertically long flat shape. The torsional rigidity is further increased. Moreover, even if the tank rails 5 and 5 are bent so as to have a bulge when viewed from the upper surface and the reinforcing ribs 5a and 5b are stretched by their outwardly extending surfaces, both of the tank rails 5 and 5 are Since the thickness of the outer side wall o located on the outer side is larger than the thickness of the inner side wall i on the inner side, the outer surfaces of the tank rails 5 and 5 have irregularities and skin roughness that are unaesthetic. Occurrence is suppressed. Therefore, in the arrangement in which the frame is exposed on both outer side surfaces of the vehicle body, the commercial value is hardly reduced.

As mentioned above, the hollow tank rails 5, 5
By providing the reinforcing ribs 5a and 5b in the interior of the pipe, there is also an effect of preventing the generation of resonance noise that tends to occur in the case of a relatively large pipe cavity. Further, since the outer wall o of the hollow tank rails 5, 5 is thick and the inner wall i is thin,
Prevents resonance with the engine sound and makes it difficult for the internal sound to come out. In addition, it is extremely difficult to bend the vertically long flat pipe that constitutes the tank rail 5 in three dimensions because of its configuration, but since it is relatively easy to bend in two dimensions, the side surface as in the above-described embodiment. When viewed from above, it is substantially linear and there is no bending on that surface. On the other hand, when viewed from above, the two tank rails 5 and 5 have a bulge in the middle part corresponding to the engine 11 and the like. By bending as described above and performing bending processing only in two dimensions, a vertically long flat pipe having a thick outer wall is used, but the processing is easy. Further, by using the pipe 14 made of aluminum extruded material in this way, by press punching,
Compared with a so-called hollow tank rail, the die cost is significantly lower and the overall cost can be reduced.

In the above embodiment, the notch portion 5c is provided in the lower portion of the rear end of the tank rail 5, and by providing the notch portion 5c, even if the rear portion of the tank rail 5 is lowered largely obliquely downward, By allowing 11 parts to be suspended at an appropriate height and lowering the rear part of the tank rail 5 obliquely downward, the tank rail does not interfere with the foot contact when the driver rides on the motorcycle. I am trying. Further, a recess 5d is integrally formed in the inner wall i of the tank rail 5 in the lengthwise direction thereof, and the recess 5d can be used for laying a wire harness or the like.

[0012]

In the present invention, elongated flat pipe according extruded aluminum is used as a tank rail, inclined surface is formed on the outer wall upper surface of the tank rails, the longitudinal length in the cross-sectional shape of the tank rails The length is more than three times the lateral length of the tank rail. By using a sufficiently long flat pipe with such a configuration, it is lightweight and has extremely high rigidity in the vertical direction and torsional rigidity of the tank rail, and it is easy to bend the tank rail in the left-right direction without impairing the aesthetic appearance. Therefore, the pair of left and right tank rails connected to the head pipe can extend substantially linearly rearward and obliquely downward in a side view from the head pipe. And, the vertical rigidity and torsional rigidity of the tank rail are extremely high, and the strength required for the vehicle body frame of the motorcycle without using the down tube,
Since it has rigidity, it is possible to easily and sufficiently secure the minimum ground clearance, and it is also extremely easy to design the wheel base to be short. Since the length in the vertical direction of the tank rail with the above configuration is sufficiently large compared to the length in the width direction,
A wide space can be secured between the pair of left and right tank rails (inside). Further, since the tank rails are arranged so as to be exposed on both outer side surfaces of the vehicle body, there is an effect on the external design. Moreover, the sloped surface formed on the upper portion of the outer side wall of the tank rail is a relief for the rider's knees, and the width of the rider's legs is narrowed.

[Brief description of drawings]

FIG. 1 is a schematic side view of a vehicle body frame of a motorcycle according to an embodiment of the present invention.

FIG. 2 is a top view of a main part of the vehicle body frame of the motorcycle according to the embodiment of the present invention.

FIG. 3 is a top view of the tank rail as viewed from the direction of arrow A in FIG.

4 is a sectional view taken along line IV-IV in FIG.

[Explanation of symbols]

 1 Head pipe 5 Tank rail 14 Flat pipe 15 Inclined surface

Claims (1)

(57) [Claims] 1. A pair of left and right tank rails connected to a head pipe extend substantially linearly rearward and obliquely downward in a side view from the head pipe so that the tank rails are exposed on both outer side surfaces of the vehicle body. is disposed, elongated flat pipe according extruded aluminum is used as a tank rail, inclined surface is formed on the outer wall upper surface of the tank rails, lateral length of the tank rail longitudinal length in the cross-sectional shape of the tank rails The body frame of a motorcycle that is more than three times the length.