JPH11263270A - Car body frame structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs and to provide high rigidity by forming a pivot plate to have a pair of opposing left and right side walls by pressmoulding, forming recessed and projecting parts in parts of these side walls and providing a pivot part in the projecting part. SOLUTION: A pivot pipe 60 crosses each center part of the upper and lower directions of left and right side walls 50 to be put through in a car width direction, and its outer peripheral part is welded to the side wall 50 all around. The tip bosses 62 of a pair of arm parts 61 formed in the front end left and right sides of a rear arm are disposed in both ends of the axial direction of the pivot pipe 60 so as to coincide shaft holes, the pivot shaft 25 of a long bolt shape is inserted into each tip boss 62 and the shaft hole of the pivot pipe 60 from one side and, from the other side, a protruded shaft end part is fastened by a nut 64, and thereby a rear fork is supported on the pivot plate so as to be freely rotated. Three ribs 66 protruded in upper and lower directions by being punched out are formed as projecting parts, and the peripheral part of each rib 66 becomes a relative recess 67.

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 structure of a motorcycle, and more particularly to a pivot plate structure thereof.

[0002]

2. Description of the Related Art It is known that a motorcycle body frame is provided with a pivot plate behind the engine for supporting the engine, and a pivot portion for supporting the front end of a rear fork is provided on the pivot plate. Have been. The pivot plate is required to have high rigidity because of the large load of the engine and the impact load from the rear wheel, and an aluminum casting may be used.

[0003]

By the way, if the pivot plate is made of an aluminum casting as described above, the cost is greatly increased. Therefore, if the pivot plate can be made into a press-formed product such as an iron plate, it is most preferable in terms of cost. . But,
When using a pressed iron plate, it is difficult to obtain high rigidity if the size is large, so relatively small ones are attached by welding using the corners etc. of the pair of frame members on the left and right. There were restrictions.

[0004]

In order to solve the above-mentioned problems, a vehicle body frame structure according to the present invention has a pivot plate for supporting the engine behind the engine, and a pivot portion provided on the pivot plate. In a motorcycle that supports a rear fork so that it can swing up and down, the pivot plate is formed so as to include a pair of left and right opposite side walls by press molding,
An uneven portion is formed on a part of the side wall, and the pivot portion is provided on the convex portion.

[0005]

According to the present invention, a pivot plate is provided so as to form a pair of side walls by press forming. The engine is supported by the pivot plate, and an uneven portion is formed on the side wall. Since the pivot portion is provided on the projection, the coupling rigidity between the pivot portion and the pivot plate can be increased, and sufficient rigidity can be obtained as a whole.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an automatic 2 to which the embodiment is applied.
Outline the structure of the wheeled vehicle. FIG. 2 is a left side view in the traveling direction in the appearance of the motorcycle. The motorcycle is configured as an American type, and has a front wheel 1 and a rear wheel 2 forming a long wheel base, a front fork 3 having a large caster angle, It has a characteristic structure such as a drop handle 4, a teardrop type fuel tank 5, a tandem seat 6 having a relatively low mounting position, and a backrest 7 provided at a rear portion thereof.

The engine 8 disposed between the front and rear wheels is a horizontal engine in which an air-cooled cylinder 9 is laid substantially horizontally in the front-rear direction. The engine 8 takes in air-fuel mixture from a carburetor 10 disposed above the cylinder unit 9, and is exhausted through an exhaust pipe 11 and a muffler 12 extending rearward from a lower portion of the cylinder unit 9.

The carburetor 10 is supplied with fuel from the fuel tank 5 and is supplied with fresh air from the rear air cleaner 13.
The carburetor 10 is disposed in a space between the front side covers 14 provided below the fuel tank 5 as a pair.

The front side cover 14 has a fuel tank 5
Is provided in the space below the front part of the and above the cylinder part 9,
The front end covers the side of the horn 15 and the horn 15
Various electric components are also arranged between the carburetor 10 and the carburetor 10. The horn 15 is also an electrical component.

The engine 8 is supported by a front portion of a body frame which has a substantially loop shape in a side view (FIG. 2). The front portion is constituted by a head pipe 16, an upper pipe 17, a lower pipe 18, and a pivot plate 20, The upper pipe 17 extends rearward from the head pipe 16 along the center of the vehicle body to support the fuel tank 5, and is bent substantially at the center of the vehicle body and extends downward to be connected to the pivot plate 20.

The lower pipe 18 is provided as a pair of right and left parts. The lower pipe 18 extends from the head pipe 16 in the vehicle width direction and extends downward, bends below the cylinder part 9 and further goes rearward, and is located on the side of the pivot plate 20 in a side view. Extend to overlap,
Here, it is connected to a cross pipe 21 (FIG. 2) extending through the pivot plate 20 in the vehicle width direction.

A rear portion of the body frame extends substantially horizontally rearward from the bent portion of the upper pipe 17 as a pair of left and right sides to support the tandem seat 6, and a lower pipe 1
8 and a side frame 23 extending obliquely upward and rearward from the side of the pivot plate 20 and connected to an intermediate portion of the seat rail 22 to form a substantially truss-like shape.

A front end of a rear fork 24 is supported on the pivot plate 20 by a pivot shaft 25 so as to be vertically swingable. The rear fork 24 extends rearward and the rear wheel 2 is rotatable to the rear end. Supported by A shock absorber 26 is provided between a connection between the seat rail 22 and the side frame 23 and a rear end of the rear fork 24.

The rear wheel 2 is driven by a chain 29 wound around a driven sprocket 27 provided concentrically on a side surface thereof and a drive sprocket 28 of the engine 8.

The front fork 3 is of a known telescopic type, and the upper part thereof is rotatably supported by the head pipe 16 via a bottom bridge 30 and a top bridge 31. A shell-type headlight 32 and a pair of left and right front blinkers 33 are supported on the bottom bridge 30, and a meter 34 is supported on the top bridge 31.

Reference numeral 35 in the figure denotes a front fender, 36
Is a front license plate, 37 is a carrier, 38 is a rear fender, 39 is a tail lamp, 40 is a mudguard, 41 is a rear blinker, and 42 is a rear license plate.

Further, reference numeral 43 denotes a change pedal,
It is provided at a front position below the cylinder section 9.
44 is a step for a rider, 45 is a main stand, 4
Reference numeral 6 denotes a step bracket attached to the side frame 23, and a tandem step 47 is attached to a rear end thereof.

Next, the structure of the pivot plate will be described. FIG. 1 is an enlarged side view of the pivot plate, FIG. 3 is an overall side view of the vehicle body frame, FIG. 4 is a top view of the pivot plate (in the direction of arrow A in FIG. 1), and FIG. FIG. 6 is a sectional view showing the state of connection with the rear fork along the line 6-6 in FIG.

The pivot plate 20 with which the lower part of the upper pipe 17 abuts has a substantially U-shape whose cross section is opened forward (FIG. 6), and a pair of side walls 50, 50 and a back wall 51 where these are continuous. And the rear wall 51 is substantially parallel to the vehicle width direction.

However, the pivot plate 20 is formed by welding the left and right divided bodies having a substantially L-shaped cross section at the center at the center in the vehicle width direction and welding them together at the center. A welded portion 52 is formed at the center of each of the ceiling portions to be welded.

An arm 53 projecting forward is formed at the upper part, and an engine mount 54 is supported at the tip thereof. The same engine mount 55 is also supported at a substantially central portion in the vertical direction of the side wall 50.

The upper part of the arm 53 is a ceiling 56 (FIG. 4).
An opening 57 for passing the upper pipe 17 is formed at the center thereof, and a vertical rib 58 is formed along the mating portion 52 at the center thereof, and is welded to the upper pipe 17. ing.

A pivot pipe 60 penetrates and traverses the left and right side walls 50 at the center in the vertical direction in the vehicle width direction, and the outer periphery thereof is welded to the side walls 50 (FIG. 6). The pivot pipe 60 forms a pivot portion of the present invention.

Each of the arm portions 6 formed on the left and right sides of the front end of the rear arm 24 at both ends in the axial direction of the pivot pipe 60.
One end boss 62 is disposed so that the shaft holes coincide with each other, and a shaft end portion protruding from the other side by passing the long bolt-shaped pivot shaft 25 from one side through the shaft hole of each end boss 62 and the pivot pipe 60. Are fastened by a nut 64, whereby the rear fork 24 is rotatably supported by the pivot plate 20.

A cross pipe 65 penetrates between the lower portions of the left and right side walls 50 (FIG. 1), and the left and right ends thereof are welded to the lower pipe 18. The frame 23 continuously extends rearward.

The pivot plate 20 is obtained by press-molding an appropriate metal such as an iron plate. At this time, a plurality of concave and convex portions are simultaneously formed from the side wall 50 to the back wall 51. In the case of the present embodiment, ribs 66 projecting in three vertical directions in the vertical direction are formed as projections, and the periphery of the rib 66 is a relative recess 67.

The horizontal ends 68 of the ribs 66 have a round shape and are formed so as not to reach the ends of the pivot plate 20. Of these ribs 66, the pivot pipe 60 is provided on a central portion of the rib 66.

Next, the operation of this embodiment will be described. Since the pivot plate 20 is formed by press molding of an iron plate or the like, the molding efficiency is extremely improved. In addition, since it is composed of the left and right divided bodies, molding is easy.

Further, since the ribs 66 are formed at the same time as the press forming, the rigidity of the entire pivot plate 20 can be increased, and the forming of the ribs 66 itself becomes easy. Further, by providing the pivot pipe 60 with the rib 66, the coupling rigidity between the pivot pipe 60 and the side wall 50 can be increased. In particular, since the span L between the support points of the pivot pipe 60 can be increased by the left and right side walls 50, the torsional rigidity can be increased accordingly.

Further, the upper pipe 17 and the pivot pipe 60 and the cross pipe 65 are welded with the upper pipe 17 and the lower pipe of the upper pipe 17 by passing through the pivot pipe 60 and the cross pipe 65 and vertically penetrating the lower part of the upper pipe 17. Accordingly, the rigidity of the pivot plate 20 can be increased.

[Brief description of the drawings]

FIG. 1 is an enlarged side view of a pivot plate.

FIG. 2 is a left side view in the traveling direction of the appearance of the motorcycle.

FIG. 3 is an overall side view of the vehicle body frame.

FIG. 4 is a top view of the pivot plate (in the direction of arrow A in FIG. 1).

FIG. 5 is a rear view (in the direction indicated by the arrow B) of the same.

FIG. 6 is a sectional view showing a state of connection with a rear fork taken along line 6-6 in FIG. 1;

[Description of References] 8: engine, 17: upper pipe, 18: lower pipe,
20: pivot plate, 25: pivot shaft, 50: side wall, 51: rear wall, 60: pivot pipe, 66: rib

Claims (1)

[Claims] 1. A motorcycle in which a pivot plate for supporting the engine is disposed at the rear of the engine, and a rear fork is swingably supported in a vertical direction by a pivot portion provided on the pivot plate. The pivot plate is formed so as to have a pair of left and right side walls facing each other by press molding, and an uneven portion is formed on a part of these side walls, and the pivot portion is provided on the convex portion. Body frame structure.