JPH09109981A - Drive shaft structure for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive shaft structure for a motorcycle which can improve the appearance of an exposed drive shaft. SOLUTION: The outer peripheral of a drive shaft 53 which transmits the rotation of an engine is covered with a pipe 57. One end of the pipe 57 in the axial direction is loosely fitted to the driven shaft 53 and the other end remains as it is. Therefore, the outer peripheral of the exposed driven shaft 53 is covered with the pipe 57, and the pipe 57 is rotated integrally with the driven shaft 53, however, the pipe does not contribute to the transmission of the power, so that torsion does not occur in this pipe and also even when plating is applied to the pipe, the plating is not separated. Thus, the drive shaft 53 is covered with the pipe 57 whose outer periphery is plating processed so that its appearance is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive shaft structure for a shaft drive type motorcycle.

[0002]

2. Description of the Related Art In a shaft drive type motorcycle which transmits the rotation of an engine to a rear wheel through a drive shaft, the drive shaft is often inserted into a pipe material forming a part of a rear arm, Generally, this cannot be seen from the outside.

However, when the drive shaft is inserted into the pipe material of the rear arm as in the conventional case, the drive shaft can be brought too close to the rear wheel because the pipe material exists between the drive shaft and the rear wheel. As a result, the width of the vehicle body widens.

Further, if the drive shaft is covered with a part of the rear arm, the degree of freedom in the appearance of the motorcycle is limited, and the rear wheel cannot be moved in the longitudinal direction of the vehicle body to be attached or detached.
There is a problem in that the rear wheels have to be moved laterally (vehicle width direction) to be detached and attached, and as a result, the workability of attaching and detaching the rear wheels deteriorates and the rear arm width increases.

Therefore, it is conceivable that the drive shaft is exposed and the arm portion of the rear arm is arranged above and below the drive shaft.

[0006]

However, in the case of exposing the drive shaft as described above, if the outer peripheral surface of the drive shaft is plated with, for example, chrome in order to enhance the appearance of the drive shaft, the drive shaft accompanying the power transmission. As a result of the twisting, the chrome plating on the outer peripheral surface of the chrome is cracked and the chrome plating is peeled off.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a drive shaft structure for a motorcycle capable of enhancing the appearance of the exposed drive shaft.

[0008]

In order to achieve the above object, the invention according to claim 1 covers the outer periphery of the drive shaft for transmitting the rotation of the engine to the rear wheels with a pipe, and one end in the axial direction of the pipe. Is fitted to the drive shaft, and the other end of the pipe is loosely fitted to the drive shaft.

The invention according to claim 2 is characterized in that, in the invention according to claim 1, the outer peripheral surface of the pipe is plated.

Therefore, according to the present invention, the exposed outer circumference of the drive shaft is capped with the pipe, and the pipe rotates integrally with the drive shaft, but since it does not contribute to power transmission, it is not twisted. Even if the outer peripheral surface of this pipe is plated, the plating does not come off. Therefore, the drive shaft is covered with a pipe whose outer peripheral surface is plated, so that its appearance is improved.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view of a motorcycle 1, in which 2 is a head pipe located in the upper front part of the vehicle body,
A steering shaft (not shown) is rotatably inserted in the head pipe 2. An upper end of a front fork 5 is supported on the steering shaft via a top bridge 3 and a bottom bridge 4, and a front wheel 6 is rotatably supported on the lower end of the front fork 5.
A handle 7 is attached to the top bridge 3.

A main frame 8 and a down tube 9 extend rearward of the vehicle body from the head pipe 2, and they constitute a vehicle body frame 10.

Details of the structure of the vehicle body frame 10 will now be described with reference to FIGS. 2 is a side view of the vehicle body frame, FIG. 3 is a plan view of the vehicle body frame, and FIG. 4 is a view in the direction of arrow A in FIG.

As shown in FIG. 2, a pair of left and right main frames 8 extend obliquely downward from the head pipe 2 toward the rear of the vehicle in a side view. As shown in FIG.
In a plan view, the pair of left and right main frames 8 spreads left and right from the head pipe 5 toward the rear of the vehicle body, then extend in parallel, and then are narrowed and finally spread toward the rear of the vehicle body.

Further, as shown in FIG. 2, the pair of left and right down tubes 9 extend obliquely downward toward the rear of the vehicle body from the head pipe 2 and are then bent toward the rear of the vehicle body to form a main frame. The lower part of 8 extends substantially horizontally toward the rear of the vehicle body. Then, as shown in FIG. 3, the pair of left and right down tubes 9 gradually expands left and right from the head pipe 5 toward the rear of the vehicle body in a plan view, and then is substantially wider than the widths of the left and right main frames 8. It is parallel and extends to the rear of the vehicle.

The rear ends of the main frame 8 and the down tube 9 on the same side are connected to each other by a pair of left and right rear end tubes 11 having an arc shape. A closed loop including the head pipe 5, the main frames 8, the down tubes 9 and the rear tubes 11 is independently provided on the left and right sides. The left and right closed loops are gussets 12 installed between the left and right main frames 8, a bracket 13 having a U-shaped cross section, a cross member 14, and a cross pipe 1 horizontally installed between the left and right down tubes 9.
5 (see FIG. 4).

By the way, in the body frame 10,
A pivot portion 16 of a rear arm 36, which will be described later, is arranged in each of the left and right closed loops (that is, a position in front of the rear end tube 11 with respect to the vehicle body). That is, the cross pipe 15
Is the bracket 1 on the front side of the vehicle body with respect to the rear end tube 11.
3, a vertical tube 17 is erected at the center of the cross pipe 15 in the vehicle width direction, as shown in FIG. Is attached to. And this vertical tube 1
From the middle height position of 7, pipes 18 and 19 are extended to the left and right in a substantially horizontal direction outward in the vehicle width direction. The outer ends of the pipes 18 and 19 are connected to the left and right down tubes 9. Rear arm brackets 20 and 2 which are vertically formed molded products
1 is bound.

The upper portions of the rear arm brackets 20 and 21 bulge outward in the vehicle width direction, and the pivot portions 16 are attached to the bulges. Therefore, the distance between the left and right pivots 16 in the vehicle width direction is set to be larger than the distance between the left and right down tubes 9 in the vehicle width direction. In addition, as shown in FIG.
An arcuate curved concave portion 17a is formed on the rear surface.

In FIG. 2, reference numeral 22 is a reinforcing pipe, 23 to 26 are engine mount brackets, and brackets for attaching rear seat footrests 27 (see FIG. 1) to the left and right rear end tubes 15. 28 are tied together.

As shown in FIG. 1, a V-type two-cylinder engine 30 is supported via the brackets 23 to 26 in the closed loop of the vehicle body frame 10 having the above-mentioned structure, and the front and rear of the engine 30 are supported. Exhaust pipes 31 and 32 extend rearward from the cylinders 30a and 30b on the right side (back side in FIG. 1) of the vehicle body. Since one vertical tube 17 is provided upright at the rear of the rear cylinder 30b, the exhaust pipe 32 extending from the rear cylinder 30b is freely arranged to avoid interference with the one vertical tube 17. , Its maneuverability is enhanced.

A fuel tank 33 is supported on the main frame 8 above the engine 30, and seats 34 and 35 are arranged behind the fuel tank 33. Therefore, in the present embodiment, the seat load is supported by the main frame 8 of the vehicle body frame 10 and also by the down tube 9 via the rear end tube 11.

On the other hand, a front end of a rear arm 36 is rotatably pivotably attached to the pivot parts 16 arranged in the left and right closed loops of the body frame 10, and a rear wheel 37 is attached to a rear end of the rear arm 36. Is rotatably supported.

The details of the configuration of the rear arm 36 and the rear wheel drive system will be described with reference to FIGS. 5 to 10.
5 is a side view of the rear arm, FIG. 6 is a plan view of the same, and FIG.
FIG. 8 is a rear view of the same, FIG. 8 is a side view showing a part of a rear arm in a state where a drive shaft is incorporated, FIG. 9 is a perspective view of the same, and FIG. 10 is a sectional view showing a drive shaft structure according to the present invention. .

The rear arm 36 has a U-shaped upper arm 38 and a pair of left and right lower arms 39 arranged below the upper arm 38. A rear arm end 40 is provided at the rear end of the upper arm 38 and each lower arm 39. Each is bound. Then, each rear arm end 40 is formed with a guide groove 42 for guiding and supporting the rear axle 41 (see FIG. 8), and as shown in FIG. 5, each guide groove 42 is opened toward the rear of the vehicle body. On the lower surface in the vicinity of the opening, a concave portion 42a having an arcuate curved surface for temporarily mounting the rear axle 41 when the rear wheel 37 is attached is formed.
Further, as shown in FIG. 5, a total of four bolt insertion portions 43 are formed vertically on the left rear arm end 40.
As shown in FIG. 7, the left and right rear arm ends 40 do not have a symmetrical shape, and the right rear arm ends 40
A recess 40a for inserting the brake rod 44 is formed therein.

At the front end of the lower arm 39, the left and right ends of the lower arm 39 are connected to the pivot shaft 45 supported by the pivot portion 16 through bearings (not shown). Therefore, the rear arm 36 and the pivot shaft 45 are supported by the pivot shaft 45. The rear wheel 37 that is swung up and down about the pivot portion 16 as shown in FIG.
As shown in FIG.
A rear cushion 46 is provided between them.

Further, a cross member 47 is provided horizontally between the left and right lower arms 39, and the cross member 4
7 and a pair of vertical tubes 4 between the upper arm 38
One end of the rear cushion 46 is connected to a pair of brackets 50 that are connected to the upper pipe 38 and a cross pipe 49 that is horizontally connected between the vertical tubes 48.

In the present embodiment, as shown in FIG. 4, the pivot portion of the vehicle body frame 10 and the front end portion of the rear arm 36 are covered with a resin cover 50, which is visible in a side view. Since the end tube 11 is arranged relatively rearward, the effect that the installation space of the engine 30 looks large can be obtained.

Thus, the motorcycle 1 according to the present embodiment.
Adopts a shaft drive type as a drive system,
The output shaft (not shown) of the engine 30 is a rear arm 36.
Is connected to a drive shaft 53 via a universal joint 52 (see FIG. 8) housed in a cylindrical cover 51 supported on the front end of the drive shaft.

The drive shaft 53 is serration-coupled to the universal joint 52,
By moving the drive shaft 53 in the longitudinal direction of the vehicle body, the drive shaft 53 can be engaged with and disengaged from the universal joint 52. As shown in FIG. 8, a ring-shaped elastic member 54 made of rubber is bonded inside the cylindrical cover 51, and the inner peripheral surface of the elastic member 54 has a taper that expands toward the front of the vehicle body. The surface 54a is formed.

By the way, as shown in FIGS. 8 and 9, the drive shaft 53 is exposed to the atmosphere, which is on the left side (front side in FIG. 8) of the vehicle body, and the upper arm 38 of the rear arm 36 and The space between the lower arms 39 extends substantially horizontally toward the rear of the vehicle body, and the rear end thereof is connected to a gear mechanism (not shown) housed in the rear gear case 55. Therefore, in the rear arm 36, the upper arm 38 and the lower arm 39 are arranged above and below the drive shaft 53 with the drive shaft 53 interposed therebetween.

The rear gear case 55 is attached to the left rear arm end 40. Specifically, the cap 55a in the first half of the rear gear case 55 is located at the front
Is attached to the rear arm end 40 with four bolts 43, and the main body 55b in the latter half is rear two bolts 4
It is attached to the rear arm end 40 by 3. Therefore, the torque reaction force generated with the rotation of the drive shaft 53 is received at the four mounting points of the rear gear case 55. Also, as shown in FIGS. 8 and 9,
A pin-shaped hook 56 for holding the drive shaft 53 is attached to the left vertical tube 48.
Further, as shown in FIG. 7, the left rear arm end 40
Of the rear gear case 55 on the inner side in the vehicle width direction of
A recess 40a is formed so that 5a, the main body 55b, and the boss portions 55a-1 and 55b-1 for attaching them to the rear arm end 40 can be pulled out rearward.

Further, as shown in FIG. 10, a metal pipe 57 is capped on the outer periphery of the drive shaft 53, and the front end portion of the pipe 57 is the drive shaft 5.
3 is fitted on the outer periphery of the drive shaft 3, and the latter half of the drive shaft 53 is loosely fitted to form a gap therebetween. A seal ring 58 is fitted on the inner periphery of the rear end of the pipe 57, and the gap between the pipe 57 and the drive shaft 53 is hermetically sealed by the seal ring 58. The outer peripheral surface of the pipe 57 is plated with chrome.

Thus, the rotation of the engine 30 is transmitted to the rear wheel 37 via an output shaft (not shown), the universal joint 52, the drive shaft 53, and a gear mechanism (not shown).
The rear wheel 37 is rotationally driven to drive the motorcycle 1 at a predetermined speed. Further, while the motorcycle 1 is traveling, the rear wheels 37 and the rear arms 36 are subject to undulations on the road surface.
When the swings up and down around the pivot portion 16, the rear cushion 46 expands and contracts accordingly to generate a damping force,
This damping force absorbs and reduces the impact that the rear wheel 37 receives from the road surface.

By the way, as described above, the outer periphery of the drive shaft 53 is capped with the pipe 57, and the pipe 57 rotates integrally with the drive shaft 53.
Does not contribute to power transmission, so it does not twist,
The chromium plating applied to the outer peripheral surface of the pipe 57 does not peel off.

Therefore, the drive shaft 53 is covered with the pipe 57 whose outer peripheral surface is chrome-plated, and its appearance is enhanced. Further, since the gap between the pipe 57 and the drive shaft 53 is hermetically sealed by the seal ring 58, invasion of dust and the like into the pipe 57 can be reliably prevented.

Further, in this embodiment, since the drive shaft 53 is exposed, it is possible to create an image of a new shaft drive vehicle and increase the degree of freedom in the appearance of the motorcycle 1, and to set the rear wheel 37 in the front-rear direction. It can be removed and attached with good workability.

Here, the work for attaching and detaching the rear wheel 37 will be described.

To remove the rear wheel 37 from the vehicle body, after the rear axle 41 is disengaged from the rear arm 36, the rear wheel 37 is removed.
Should be moved to the rear of the vehicle body together with the drive shaft 53. Then, the rear axle 41 causes the left and right rear arm ends 4 to
The guide shaft 42 moves rearward along the 0 guide groove 42 to come off the guide groove 42, and the drive shaft 53 is guided by the hook 56 to move backward, and then comes off the hook 56. It can be removed. Even if the drive shaft 53 is removed, the universal joint 52 is received by the elastic member 54 shown in FIG. Further, when the engine 30 is mounted on the vehicle body frame 10, the universal joint 52 is assembled along the taper surface 54a of the elastic member 54, so that its assembling property is enhanced.

Next, in order to assemble the rear wheel 37 together with the drive shaft 53, the drive shaft 53 is hooked by the hook 56.
Then, the rear wheel 37 is pushed forward together with the drive shaft 53 toward the front of the vehicle body, and first, the rear axle 41 is once placed in the recess 42a formed in the guide groove 42 of the left and right rear arm ends 40. At this time, the tip portion of the drive shaft 53 faces the position immediately before being fitted to the universal joint 52. However, as described above, the universal joint 52 is received by the elastic member 54 and its posture has not changed significantly. It becomes easy to align the positions. Then, if the rear wheel 37 and the drive shaft 53 are pushed forward, the drive shaft 53 moves forward while being retained by the hook 56, and the tip end portion thereof is easily serrated to the universal joint 52, and the rear axle 41 is guided. Groove 4
The rear wheel 37 can be assembled together with the drive shaft 53 by fastening the rear axle 41 to the rear arm 36 when the rear wheel 37 is set to the predetermined position.

By the way, in the present embodiment, the pivot portion 16 for supporting the rear arm 36 is attached to the vehicle body frame 1.
Since it is provided in the closed loop of 0 (that is, in the front of the vehicle body with respect to the rear end tube 11), the length of the rear arm 36 can be made longer than in the conventional case.
The riding angle of the motorcycle 1 can be enhanced by suppressing the swing angle of the vehicle to be small, and the resistance at the pivot point of the rear arm 36 and the wear of the bearing (not shown) can be suppressed. Particularly, in the present embodiment, as described above, the concave portion 17a having an arcuate curved surface is formed on the rear surface of the vertical tube 17 (see FIG. 4).
Since the pivot shaft 45 supported by the front end of the rear arm 36 can be fitted into the recess 17a of the vertical tube 17 and moved toward the front of the vehicle body, the length of the rear arm 36 can be maximized. can do.

Since the distance between the left and right pivot portions 16 supported by the vehicle body frame 10 is made wider than the distance between the left and right down tubes 9 as described above, the pivot distance between the rear arms 36 pivotally supported by the pivot portion 16 is increased. The rigidity of the rear arm 36 is increased, and the torsion of the rear arm 36 due to the action of the force from the rear wheel 37 side is suppressed.

[0043]

As is apparent from the above description, according to the present invention, the outer periphery of the drive shaft for transmitting the rotation of the engine to the rear wheels is covered with a pipe, and one end of the pipe in the axial direction is used as the drive shaft. Since it is fitted and the other end of the pipe is loosely fitted to the drive shaft, the appearance of the exposed drive shaft can be enhanced.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle.

FIG. 2 is a side view of a body frame of a motorcycle.

FIG. 3 is a plan view of a body frame of the motorcycle.

4 is a view in the direction of arrow A in FIG.

FIG. 5 is a side view of a rear arm of the motorcycle.

FIG. 6 is a plan view of the rear arm of the motorcycle.

FIG. 7 is a rear view of the rear arm of the motorcycle.

FIG. 8 is a side view showing a cross section of a part of a rear arm in which a drive shaft is incorporated.

FIG. 9 is a perspective view of the rear arm with a drive shaft incorporated therein.

FIG. 10 is a sectional view showing a drive shaft structure according to the present invention.

[Explanation of symbols]

 1 Motorcycle 30 Engine 37 Rear Wheel 53 Drive Shaft 57 Pipe 58 Seal Ring

Claims (2)

[Claims] 1. A drive shaft for transmitting rotation of an engine to a rear wheel is covered with a pipe, one axial end of the pipe is fitted to the drive shaft, and the other end of the pipe is loosely fitted to the drive shaft. A drive shaft structure for a motorcycle that is made up of at least one. 2. The drive shaft structure for a motorcycle according to claim 1, wherein an outer peripheral surface of the pipe is plated.