JP3703044B2 - Rear arm shaft attachment structure for motorcycles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rear arm shaft attachment portion structure for attaching a front end portion of a rear arm, in which a rear wheel is pivoted to a rear end portion, to a body frame of a motorcycle via a pivot shaft.
[0002]
[Prior art]
In motorcycles, the front ends of the left and right rear arms are attached to each other via a pivot shaft arranged in the vehicle body width direction near the lower part of the center of the body frame in the front-rear direction, and rearward over the rear ends of the rear arms. By mounting the wheels in an adjustable manner, the rear wheels are swingably mounted on the vehicle body frame via the rear arm. In this case, the front end of each rear arm can be rotated with respect to the vehicle body frame. Conventionally, pivot shaft mounting brackets are integrally attached to the vehicle body frame on both the left and right sides of the vehicle body by welding so as to be pivotally mounted, and the pivot is pivoted across the left and right pivot shaft mounting brackets. A shaft is installed, and the front end portion of each rear arm is rotatably inserted into the pivot shaft.
[0003]
[Problems to be solved by the invention]
By the way, with regard to the structure of the rear arm shaft attachment portion of the conventional motorcycle as described above, the front end portion can be rotated only by installing the pivot shaft only by the pivot shaft mounting brackets welded to the vehicle body frame on both sides of the vehicle body. Since the rigidity to support the rear arm that swings at the center is low, in practice, this part needs to be greatly reinforced, and as a result, the number of parts for installing the pivot shaft increases, and their attachment Space will also increase.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a vehicle body frame via a pivot shaft disposed in the vehicle body width direction in the vicinity of the lower portion of the center in the front-rear direction, as described in claim 1. Thus, in a motorcycle in which the front end portion of the rear arm is pivotally attached , a main pipe that extends rearward from the head pipe and bends downward in the middle, and a lower pipe that extends downward from the head pipe and bends left and right in the middle are bent backward. A tubular pivot boss for inserting and supporting the pivot shaft with respect to a vehicle body frame having a down tube is welded to the main pipe in a state where the main pipe of the vehicle body frame penetrates the skewer in the vehicle body width direction. are, optionally bracket engine mounting is welded across the said pivot boss and the main pipe, the rear end of the down tube divided into left and right body Are connected to one cross pipe extending in the direction, and the lower end of the main pipe is connected to the left and right down tubes below the part where the bracket for engine mounting is welded across the pivot boss and the main pipe. the cross pipe coupled to a rear end and is characterized that you have been connected between the left and right down tubes.
[0005]
Further, in the rear arm shaft attachment portion structure of the motorcycle described in claim 1, as described in claim 2, the front end portions of the left and right rear arms are provided outside the both ends of the pivot boss through which the pivot shaft is inserted. Are respectively inserted into the pivot shafts, and both ends of the pivot shaft are fixed to the left and right pivot shaft fixing brackets respectively welded to the left and right back stays outside the rear arm front end portions, respectively . The left and right backstays are respectively connected to both ends of a cross pipe connecting the rear ends of the left and right down tubes .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a rear arm shaft attachment structure for a motorcycle according to the present invention will be described below with reference to the drawings.
[0007]
FIG. 1 shows the overall appearance of a motorcycle to which the rear arm shaft mounting structure of the present invention is applied as viewed from the side. The motorcycle 1 is provided with a headlight 2 and a speedometer 3. A steering handle 5 for operating the front wheel 4 is extended greatly upward without being covered with a cowling on the upper front surface of the steering, and is behind a water droplet type fuel tank 6 installed so as to straddle the vehicle body frame. A so-called American type motorcycle in which a stepped tandem seat 8 extending above the rear wheel 7 is installed and the engine body 9 is installed under the fuel tank 6 without being covered with a cowling. is there.
[0008]
2 and 3 show a body frame of such a motorcycle 1, and the body frame 10 is a semi-cradle type frame, in which the constituent members of the frame are joined together by welding. is there.
In such a motorcycle 1 of the present embodiment, the main pipe 12 that extends rearward from the head pipe 11 and bends downward in the middle, and the down that extends downward from the head pipe 11 and bends leftward and rightward in the middle. A tubular pivot boss 28 for inserting and supporting the pivot shaft 30 with respect to the body frame having the tubes 13a and 13b penetrates the main pipe 12 of the body frame through the skewer in the body width direction. It is welded to the pipe 12. An engine mounting bracket 29 is welded across the pivot boss 28 and the main pipe 12, and the rear ends of the down tubes 13b separated to the left and right are respectively connected to a single cross pipe 16 extending in the vehicle body width direction. In addition, below the portion where the engine mounting bracket 29 is welded across the pivot boss 28 and the main pipe 12, the lower end of the main pipe 12 is connected to the rear ends of the left and right down tubes 13b. The pipe 16 is connected between the left and right down tubes 13b.
[0009]
That is, at the front portion of the vehicle body frame 10, the front end portion of one main pipe 12 that extends rearward and bends downward in the middle with respect to the head pipe 11 that pivots the steering, and extends downward. The front end of one large-diameter down tube 13a is reinforced by a frame connecting gusset 14, and the tension pipe 15 is connected across the main pipe 12 and the down tube 13a. Has been.
[0010]
The lower end of one large diameter down tube 13a is connected to a small diameter down tube 13b that extends rearward and separated to the left and right. The lower end of the main pipe 12 and the rear end of each down tube 13b are shown in FIG. As described above, both are connected to a frame connecting cross pipe 16 extending in the width direction of the vehicle body, and left and right back stays 17 extending obliquely rearward are connected to both ends of the cross pipe 16 respectively. ing.
[0011]
In front of the middle bent portion of the main pipe 12, seat rails 18 that are divided into left and right and extend rearward are respectively connected, and the rear ends of the seat rails 18 are respectively connected in the middle of the backstays 17. Each of the left and right backstays 17 is connected with a tube 19 welded with a mounting bracket 21 for a passenger's footrest in the middle thereof.
[0012]
The vehicle body frame 10 in which the structural members of the frame are integrally connected as described above is provided with a tank locking bracket 22 for locking the front portion of the fuel tank at the upper part of the main pipe 12. A tank fixing bracket 23 for fixing the rear end of the fuel tank and locking the front end of the seat is provided on the left and right seat rails 18 at the front portion of the seat rail 18.
[0013]
In addition, a hollow gusset 24 made of a sheet metal hollow structure is integrally attached to the connecting portion between the left and right seat rails 18 and the back stay 17 by welding. 24, two front and rear cross tubes 25 are integrally fixed by welding, and a mounting bracket 26 for mounting the upper end of the rear cushion is provided across the two cross tubes 25.
[0014]
In addition, a rear bracket 27 for supporting the rear fender from above and for fixing the rear portion of the seat is provided over the rear end portions of the left and right back stays 17 at the rear of the hollow gusset 24. ing.
[0015]
Further, a hollow tubular pivot boss 28 for attaching a rear arm is provided in the vicinity of the lower end of the main pipe 12 above the frame connecting cross pipe 16 in a state where the main pipe 12 is skewered in the width direction of the vehicle body. An engine mounting bracket 29 is welded across the pivot boss 28 and the main pipe 12 below the pivot boss 28 so as to reinforce the mounting of the pivot boss 28.
[0016]
In addition to the brackets described above, the vehicle body frame 10 includes a rear arm pivot shaft fixing bracket 31, a regulator mounting bracket 32, an engine mounting bracket 33, a side stand mounting bracket 34, and a side cover mounting bracket. Various parts mounting brackets, such as 35 and 36, an air cleaner mounting bracket 37, and a main stand mounting bracket 38, are integrally fixed to an appropriate position of the vehicle body frame 10 by welding.
[0017]
As shown in FIG. 1, a steering portion having a steering handle 5 on the upper side and a front fork 41 on the lower side is fixed to the upper end of the main pipe with respect to the vehicle body frame 10 formed as described above. The front head 4 is pivotally supported at the lower end of a front fork 41 having a cushion portion.
[0018]
On the one side of the front wheel 4 is disposed a disc brake 42 comprising a caliper 42a attached to the front fork 41 side and a disc 42b attached to the wheel side of the front wheel. A front fender 43 is attached to the front fork 41 so as to cover the upper part of the front wheel 4 from above.
[0019]
On the other hand, as shown in FIG. 5, a pivot shaft 30 longer than that is inserted into the pivot boss 28 fixed in a skewered state in the width direction of the vehicle body in the vicinity of the lower end of the main pipe 12. Thus, outside the both ends of the pivot boss 28, the left and right front end portions 45a of the rear arm 45 have bushes coated with grease between the shaft 30 and the front end portion 45a, respectively, and an oil seal on the inner end side thereof (not shown). ) Are supported so as to be freely rotatable.
[0020]
Both end portions of the pivot shaft 30 projecting outward from the rear arm front end portion 45a are supported by pivot shaft support brackets 31 fixed to the left and right back stays 17, and the pivot shaft 30 (bolt) is the bracket. The outer end side of each rear arm front end 45a that is fixed to the pivot 31 with a nut and is fitted to the pivot shaft 30 is a cover-like seal member 31a provided inside each pivot shaft support bracket 31. Each is oil sealed.
[0021]
The rear arm 45 is formed by integrally connecting a plurality of constituent members by welding. As shown in FIGS. 6 and 7, the rear arm 45 is connected to the left and right rear arm main bodies 45 b having front end portions 45 a fitted into the pivot shaft 30. Thus, both ends of the U-shaped pipe 45c are connected to the rear end of the U-shaped pipe 45c, and a cross member 45d is connected to the middle of the U-shaped pipe 45c and the cross member 45d. The left and right connecting pipes 45e are connected to each other, and the reinforcing pipes 45f are connected to the left and right connecting pipes 45e and the rear arm main body 45b.
[0022]
In addition, a mounting bracket 46 for mounting the lower end of the rear cushion is integrally fixed to the rear arm 45 by welding to the cross member 45d, and the mounting bracket 47 for mounting the chain cover is at an appropriate position. As shown in FIG. 1, they are integrally fixed by welding, and are provided with elongated holes 45g at the rear end portions of the left and right rear arm bodies 45b for fixing the axles of the rear wheels in an adjustable manner. As described above, the rear wheel 7 is pivotally mounted on the rear end portion of the rear arm 45.
[0023]
Corresponding to the rear cushion lower end mounting bracket 46 of the rear arm 45, as already shown in FIGS. 2 and 3, two front and rear cross tubes 25 are integrally welded to the left and right hollow gussets 24, respectively. A rear cushion upper end mounting bracket 26 is provided so as to extend over the two cross tubes 25, and thereby a rear part interposed between the vehicle body frame 10 and the rear arm 45 as shown in FIG. 8. The cushion 50 is attached across the upper end mounting bracket 26 on the vehicle body frame side (cross tube 25) and the lower end mounting bracket 46 on the rear arm 45 side.
[0024]
In the motorcycle 1 in which the front wheel 4 and the rear wheel 7 are respectively installed with respect to the vehicle body frame 10 as described above, the fuel tank 6 is connected to the main pipe 12 and the seat rail 13 as shown in FIGS. The tandem seat 8 is installed so as to be positioned by the tank locking bracket 22 and the tank fixing bracket 23 so as to extend over the hollow gusset 24 at the rear of the fuel tank 6. It is installed so as to be positioned by the bracket 27.
[0025]
A rear fender 51 that covers the upper part of the rear wheel 7 from above is fixed by a back stay 17 and a rear bracket 27. Outside the rear fender 51, rear stays 52 are provided on the left and right sides of the vehicle body, respectively. The backrest mounting stay 53 for mounting the backrest 54 of the tandem seat 8 is erected at the rear part of the left and right rear stays 52 so as to connect the two. ing.
[0026]
A blinker 55 is installed on the left and right of the rear portion of the rear stay 52. A tail light 56 is installed on the rear upper surface of the rear fender 51, and a license for attaching a license plate on the lower surface of the rear portion. A bracket 57 and a license lamp 58 for irradiating the license plate are respectively installed.
[0027]
Below the fuel tank 6 between the front wheels 4 and the rear wheels 7, in the space surrounded by the main pipe 12, the down tubes 13a and 13b, and the back stay 17, the engine body 9, the carburetor 60, and an air cleaner (not shown). From the front side of the engine body 9, the exhaust pipe 61 is once extended downward as shown in FIG. 1, and then passes through the right side of the vehicle body as shown in FIG. The rear end is connected to a muffler 62 located on the right side of the rear wheel 7.
[0028]
On the other hand, on the left side of the vehicle body on which the muffler 62 is not disposed, as shown in FIG. 1, an output shaft sprocket (not shown) projecting laterally from the transmission portion continuing to the lower rear of the engine body 9, A chain 64 for transmitting the rotational driving force of the engine body 9 to the rear wheel 7 is hung over the sprocket 63 fixed to the hub of the wheel 7.
[0029]
As shown in FIG. 9, a driver's footrest 65 is installed on each side of the vehicle body at the lower part of the vehicle body between the front wheel 4 and the rear wheel 7, and a change pedal 68 and a side stand 67 are provided on the left side of the vehicle body. A brake lever 69 and a kick pedal 70 are installed on the right side of the vehicle body, and, as shown in FIG. 1, passenger footrests 66 are installed on both sides of the vehicle body in front of the rear wheel 7, respectively. One center stand 71 is installed behind both sides of the vehicle body 67.
[0030]
Further, the motorcycle 1 in which the respective components are installed as described above is provided with a meter cover 72 with a fuel meter 73 attached to the fuel tank 6 on the upper surface thereof, and behind the steering head pipe 11. A frame cover 74 that covers the front side of the fuel tank 5 and a frame cover 75 that covers both lower sides of the fuel tank 5 are provided.
[0031]
Further, on both sides below the front part of the tandem seat 8, two side covers 76 are provided so as to cover both sides of an air cleaner (not shown), and covers the lower side of the side cover 76. 77, a cover 78 for covering the passenger footrest 66 and the like are provided on both sides of the vehicle body. On the rear side thereof, a sprocket (not shown) of the engine output shaft and a sprocket 63 of the rear wheel 7 are provided. A chain case 79 is provided on the left side of the vehicle body with respect to the rear arm 45 to cover the upper half of the chain 64 that has been stretched.
[0032]
By the way, in the motorcycle 1 of the present embodiment having the above-described configuration, as described above, the rear arm mounting pivot boss 28 is located above the frame connecting cross pipe 16 and in the vicinity of the lower end of the main pipe 12. However, they are integrally welded with the main pipe 12 skewered in the width direction of the vehicle body, and the pivot shaft 30 is inserted into the pivot boss 28.
[0033]
Therefore, the pivot boss 28 is integrally fixed to the rigid main pipe 12 without particularly requiring a bracket for attaching the pivot boss 28, and the mounting space for the pivot boss 28 is increased. In addition, the pivot shaft 30 is widely and reliably supported by the pivot boss 28.
[0034]
In addition, since the engine mounting bracket 29 is welded across the pivot boss 28 and the main pipe 12, a special reinforcing member is not required, and a member used for another purpose such as the engine mounting bracket 29 is used. Thus, the fixing of the main pipe 12 and the pivot boss 28 is further reinforced, and the attachment of the engine mounting bracket 29 to the vehicle body frame and the reinforcement of the joint between the pivot boss 28 and the main pipe 12 are welded once. Done at the same time in the work.
[0035]
Furthermore, in the present embodiment, both end portions of the pivot shaft 30 protruding outward from the rear arm front end portion 45a are fixed to the left and right backstays 17 via the respective pivot shaft support brackets 31, that is, high Since both ends of the pivot shaft 30 supported at the center by the rigidly fixed pivot boss 28 are further fixed to the respective backstays 17, each of the pivot shafts 30 fitted and inserted into the pivot shaft 30. The rear arm front end portion 45a is supported with high rigidity with respect to the vehicle body frame.
[0036]
【The invention's effect】
According to the rear arm shaft attachment portion structure of the motorcycle of the present invention as described above, the pivot boss that supports the pivot shaft of the rear arm has high strength with respect to the vehicle body frame without requiring a special mounting member or reinforcing member. It can be mounted with high rigidity, and the pivot shaft can be widely supported by the pivot boss, and the mounting of the engine mounting bracket and the reinforcement of the joint between the body frame and the pivot boss can be done in one operation. It can be performed simultaneously, and the number of parts for attaching the pivot boss can be reduced, the attachment space can be reduced, and the degree of freedom of layout of other parts in the part can be increased.
[Brief description of the drawings]
FIG. 1 is a side view showing the appearance of a motorcycle to which a rear arm shaft mounting portion structure of the present invention is applied.
2 is a side view showing a body frame of the motorcycle shown in FIG. 1. FIG.
3 is a top view of the vehicle body frame shown in FIG. 2. FIG.
4 is a top view showing a connecting portion of a main pipe, a down tube, and a back stay in the vehicle body frame shown in FIG. 2;
FIG. 5 is a partial cross-sectional top view of the rear arm shaft mounting portion showing an embodiment of the rear arm shaft mounting portion structure of the present invention.
6 is a side view showing a rear arm in the motorcycle shown in FIG. 1. FIG.
7 is a top view of the rear arm shown in FIG. 6. FIG.
FIG. 8 is an explanatory side view showing a rear cushion arrangement relationship and a mounting state in the motorcycle shown in FIG. 1;
FIG. 9 is an explanatory top view showing the positional relationship of each part installed in the lower part of the vehicle body such as a muffler, a chain, and a side stand in the motorcycle shown in FIG. 1;
[Explanation of symbols]
1 Motorcycle 10 Body frame
11 Head pipe 12 Main pipe
13a Down tube (part extending downward from the head pipe)
13b Down tube (separated part)
16 Cross pipe (cross pipe connecting the rear end of down tube)
17 Backstay 28 Pivot Boss 29 Engine Mounting Bracket 30 Pivot Shaft 31 Pivot Shaft Fixing Bracket 45 Rear Arm 45a Rear Arm Front End

Claims (2)

In a motorcycle in which the front end of the rear arm is pivotally attached to the body frame via a pivot shaft arranged in the vehicle body width direction near the lower part of the center in the front-rear direction, the motorcycle extends rearward from the head pipe and moves downward in the middle. A tubular pivot boss for inserting and supporting the pivot shaft with respect to a vehicle body frame having a main pipe that bends inward and a down tube that extends downward from the head pipe and bends to the left and right in the middle. However, it is welded to the main pipe in a state where the main pipe of the body frame penetrates the skewer in the vehicle body width direction, and the engine mounting bracket is welded across the pivot boss and the main pipe , The rear end of the separated down tube is connected to one cross pipe extending in the vehicle body width direction, and the pivot boss Across the main pipe at the lower portion bracket engine mounting are welded, the lower end of the main pipe, the cross pipe connecting the rear ends of the left and right down tubes, are connected between the left and right down tubes A structure for attaching a rear arm shaft of a motorcycle, characterized by The front ends of the left and right rear arms are fitted and inserted into the pivot shafts outside the both ends of the pivot boss through which the pivot shaft is inserted, and the both ends of the pivot shaft are connected to the left and right backstays outside the rear end of each rear arm. The left and right back stays are respectively connected to both ends of a cross pipe connecting the rear ends of the left and right down tubes. The rear arm shaft attachment structure for a motorcycle according to claim 1.

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