JP4008096B2 - Body frame structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a body frame structure of a motorcycle, and more particularly to a pivot plate structure thereof.
[0002]
[Prior art]
It is known that a body frame of a motorcycle is provided with a pivot plate for supporting the rear of the engine and a pivot portion for pivotally supporting the front end portion of the rear fork. This pivot plate is required to have high rigidity because of the heavy load of the engine and the impact load from the rear wheel, and an aluminum cast product may be used.
[0003]
[Problems to be solved by the invention]
By the way, if the pivot plate is made of an aluminum casting as described above, the cost is greatly increased. If this can be made into a press-molded product such as an iron plate, it is most preferable in terms of cost. However, when using a steel plate press product, it is difficult to obtain high rigidity if it is large, so a relatively small object is attached by welding using the corners of the frame members that make a pair of left and right, etc. Etc. were restricted.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the vehicle body frame structure according to the present invention has a pivot plate for supporting the engine behind the engine, and the rear fork can be swung vertically by a pivot portion provided on the pivot plate. in motorcycle for supporting the said pivot plate formed to include a pair of left and right side walls that face by press molding, an uneven portion formed on a part of the side walls, said pivot to the projecting portion part of providing Rutotomoni, the pivot plate is provided one on the vehicle body center, the projecting portion of the pivot plate is constituted by the ribs, pivot pipes penetrating the left and right and characterized in that it is welded on the surface of the rib To do.
[0005]
【The invention's effect】
A pivot plate is provided to form a pair of side walls by press forming, and the pivot plate supports the engine, and the side wall portion is formed with an uneven portion, so that it can be manufactured with high rigidity and at a low cost. Since the portion is provided, the coupling rigidity between the pivot portion and the pivot plate can be increased, and sufficient rigidity can be obtained as a whole.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
First, the structure of a motorcycle to which the embodiment is applied will be outlined. FIG. 2 is a left side view of the direction of travel in the appearance of the motorcycle. The motorcycle is configured as an American type, and includes 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 characteristic structures such as a drop handle 4, a teardrop type fuel tank 5, a tandem seat 6 with a relatively low mounting position, and a backrest 7 provided at the rear part.
[0007]
The engine 8 disposed between the front and rear wheels is a horizontal engine in which an air-cooled cylinder portion 9 is laid substantially horizontally in the front-rear direction. The engine 8 sucks air-fuel mixture from a carburetor 10 disposed above the cylinder portion 9 and is exhausted through an exhaust pipe 11 and a muffler 12 that extend rearward from the lower portion of the cylinder portion 9.
[0008]
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 sandwiched between a pair of left and right front side covers 14 provided below the fuel tank 5.
[0009]
The front side cover 14 is provided in a space below the front portion of the fuel tank 5 and above the cylinder portion 9, and the front end portion covers the side of the horn 15, and various electrical components are placed between the horn 15 and the vaporizer 10. It comes to arrange. The horn 15 is also an electrical component.
[0010]
The engine 8 is supported by a front portion of a vehicle body frame having a substantially loop shape in a side view (FIG. 2), and the front portion includes a head pipe 16, an upper pipe 17, a lower pipe 18, and a pivot plate 20, and 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 at substantially the center of the vehicle body and extends downward to be connected to the pivot plate 20.
[0011]
The lower pipe 18 is provided as a pair of left and right, extends from the head pipe 16 in the vehicle width direction and extends downward, bends below the cylinder portion 9 and further toward the rear, and overlaps the side of the pivot plate 20 in a side view. And is connected to a cross pipe 21 (FIG. 2) extending through the pivot plate 20 and extending in the vehicle width direction.
[0012]
The rear portion of the vehicle body frame extends from the bent portion of the upper pipe 17 in a pair of left and right sides substantially horizontally and supports the tandem seat 6, and the lower pipe 18 continues from the side of the pivot plate 20 obliquely. A side frame 23 that extends rearward and connects to an intermediate portion of the seat rail 22 has a substantially truss shape.
[0013]
The pivot plate 20 supports the front end portion of the rear fork 24 so as to be swingable in the vertical direction by the pivot shaft 25. The rear fork 24 extends rearward and the rear wheel 2 is rotatably supported at the rear end portion. The A shock absorber 26 is provided between the connecting portion of the seat rail 22 and the side frame 23 and the rear end portion of the rear fork 24.
[0014]
The rear wheel 2 is chain-driven by a chain 29 wound between a driven sprocket 27 concentrically provided on a side surface thereof and a drive sprocket 28 of the engine 8.
[0015]
The front fork 3 is a known telescopic type, and an upper portion thereof is rotatably supported on the head pipe 16 via a bottom bridge 30 and a top bridge 31. A bullet-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.
[0016]
In the figure, reference numeral 35 denotes a front fender, 36 denotes a front number plate, 37 denotes a carrier, 38 denotes a rear fender, 39 denotes a tail lamp, 40 denotes a mud guard, 41 denotes a rear winker, and 42 denotes a rear number plate.
[0017]
Further, 43 is a change pedal, which is provided at a forward position below the cylinder portion 9. 44 is a rider step, 45 is a main stand, 46 is a step bracket attached to the side frame 23, and a tandem step 47 is attached to the rear end thereof.
[0018]
Next, the structure of the pivot plate will be described. 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 cross-sectional view showing a connection state with the rear fork taken along line 6-6 in FIG.
[0019]
The pivot plate 20 with which the lower part of the upper pipe 17 abuts has a substantially U-shape with a transverse section opened forward (FIG. 6), and has a pair of side walls 50, 50 and a back wall 51 in which these are continuous. The rear wall 51 is substantially parallel to the vehicle width direction.
[0020]
However, the pivot plate 20 is formed by welding and integrating the left and right divided bodies having a substantially L-shaped cross section that are divided into left and right at the center in the center in the vehicle width direction. A mating portion 52 welded to each center is formed.
[0021]
Further, an arm portion 53 that protrudes forward is formed at the upper portion, and an engine mount 54 is supported at the tip portion. An engine mount 55 similar to this is also supported at a substantially central portion of the side wall 50 in the vertical direction.
[0022]
The upper part of the arm part 53 is covered with a ceiling part 56 (FIG. 4), an opening part 57 for allowing the upper pipe 17 to pass therethrough is formed in the center part, and a standing rib 58 extends along the mating part 52 in the center part. And is welded to the upper pipe 17.
[0023]
A pivot pipe 60 penetrates in the center of the left and right side walls 50 in the vertical direction and crosses in the vehicle width direction, and the outer periphery thereof is welded to the side walls 50 (FIG. 6). This pivot pipe 60 forms the pivot portion of the present invention.
[0024]
A pair of tip bosses 62 of the arm portions 61 formed on the left and right of the front end portion of the rear arm 24 are arranged at both ends in the axial direction of the pivot pipe 60 so that the shaft holes coincide with each other. The rear fork 24 is rotatably supported on the pivot plate 20 by fastening the shaft end portion protruding from the other side through the shaft holes of the tip bosses 62 and the pivot pipe 60 with the nut 64.
[0025]
In addition, the cross pipe 21 passes through between the lower portions of the left and right side walls 50 (FIG. 1), and both left and right end portions are welded to the lower pipe 18, and the lower pipe 18 is connected to the side frame 23 from this weld point. It is continuously extended backward.
[0026]
The pivot plate 20 is obtained by press-molding an appropriate metal such as an iron plate. At this time, a plurality of uneven portions are formed from the side wall 50 to the back wall 51 at the same time. In the case of the present embodiment, ribs 66 protruding in three vertical directions are formed as convex portions, and the peripheral portions of the ribs 66 are relative concave portions 67.
[0027]
The horizontal end 68 of the rib 66 has a rounded (R) shape and is formed so as not to reach the end of the pivot plate 20. Among these ribs 66, the pivot pipe 60 is provided on the rib 66 in the central portion.
[0028]
Next, the operation of this embodiment will be described. Since the pivot plate 20 is formed by press forming such as an iron plate, the forming efficiency is extremely improved. In addition, since the left and right divided bodies are used, molding is easy.
[0029]
Further, since the rib 66 is formed simultaneously with the press molding, the rigidity of the entire pivot plate 20 can be increased, and the rib 66 itself can be easily molded. Furthermore, 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.
[0030]
In addition, the pivot pipe 60 and the cross pipe 65 are penetrated and traversed, and the lower part of the upper pipe 17 is vertically penetrated and welded to each other, whereby the upper pipe 17 and the pivot pipe 60 and the cross pipe 65 are also pivoted. The rigidity of the 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 direction of travel in the appearance of a motorcycle. FIG. 3 is an overall side view of a vehicle body frame. FIG. 5 is a rear view (in the direction of arrow B). FIG. 6 is a cross-sectional view showing a state of connection with the rear fork along line 6-6 in FIG.
8: Engine, 17: Upper pipe, 18: Lower pipe, 20: Pivot plate, 25: Pivot shaft, 50: Side wall, 51: Back wall, 60: Pivot pipe, 66: Rib

Claims (5)

A pivot plate for supporting the engine is arranged at the rear of the engine, and the pivot plate is press-molded in a motorcycle in which a pivot portion provided on the pivot plate supports a rear fork so as to swing up and down. formed to include a pair of left and right side walls facing in, and an uneven portion formed on a part of the side walls, the pivot portion is provided in the protrusion portion Rutotomoni,
One pivot plate is provided on the center of the vehicle body, the convex part of the pivot plate is constituted by ribs, and the pipette pipe penetrating from side to side is welded on the surface of the ribs . The pivot plate is substantially U-shaped with a cross section opened forward, has a pair of side walls and a back wall in which the side walls are continuous, and an uneven portion is formed from the side walls to the back. The vehicle body frame structure according to claim 1. The pipette plate has an arm portion protruding forward at the upper portion, the upper portion of the arm portion is covered with a ceiling portion, and an opening portion is provided at the center portion of the ceiling portion, and the vehicle body passed through the opening portion. The vehicle body frame structure according to claim 1, wherein the ceiling portion is welded to a frame. 2. The vehicle body frame structure according to claim 1, wherein a through hole is provided in a side wall of the pipe plate, and a pipe pipe is inserted into the through hole and welded. The vehicle body frame structure according to claim 1, wherein a cross pipe is passed through the pipette plate and welded.

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