JP2657661B2 - Underbody structure of motorcycle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lower body structure of a motorcycle including an engine guard that covers a lower surface of an engine, and a footrest bracket that supports a footrest.

(Prior Art) In many motorcycles, the exhaust pipe of the engine extends rearward through the lower side of the engine.

Further, since the engine of the motorcycle is usually provided at a lower portion of the vehicle body, there is a possibility that the engine may come into contact with an obstacle on a road surface during traveling. At this time, in order to prevent the engine from being easily damaged, some engines have an engine guard that covers a lower surface of the engine.

In the above case, the exhaust pipe located on the lower side of the engine may also come into contact with an obstacle on the road surface. In order to protect the exhaust pipe with a simple configuration, it is conceivable to extend one side of the engine guard to cover the lower surface of the exhaust pipe.

(Problems to be Solved by the Invention) By the way, when trying to protect the exhaust pipe as described above, if one side of the engine guard is simply extended, it becomes cantilevered and has sufficient strength. There is a possibility that it cannot be secured.

On the other hand, a motorcycle is provided with a footrest, which is generally supported by a projecting end of a footrest bracket projecting outward from a part of a vehicle body frame located on a lower side of the engine. And also in this case,
Since the footrest bracket is cantilevered, it is desired to improve the strength with a structure as simple as possible.

(Object of the Invention) The present invention has been made in view of the above-mentioned circumstances, and has a structure in which one side of an engine guard is extended to cover a lower surface of an exhaust pipe. ,
It is an object of the present invention to improve each strength of the footrest bracket with a structure as simple as possible.

(Structure of the Invention) A feature of the present invention for achieving the above object is to extend one side of an engine guard so as to cover a lower surface of an exhaust pipe located at a lower side of the engine. The point is that the projecting end side of the footrest bracket is positioned above the exhaust pipe, and the extension of the engine guard is connected to the projecting end of the footrest bracket.

(Operation) The operation of the above configuration is as follows.

One side of an engine guard 64 that covers the lower surface of the engine 25 extends to cover the lower surface of the exhaust pipe 29. That is, the lower surface of the exhaust pipe 29 is covered by using the engine guard 64. Therefore, the exhaust pipe 29 is protected by a simple configuration.

In the above case, since one side of the engine guard 64 is extended, the strength of the effect portion becomes a problem. However, the extension of this engine guard 64 and the forest bracket
The projecting ends of the 54 are connected to each other, and both the extended portion of the engine guard 64 and the footrest bracket 54 sandwich the exhaust pipe 29 from above and below, so that both have a frame-like structure, As a result, both are reinforced with each other, and the strength is improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

2 and 3, 1 is a motorcycle, 2 is a body frame thereof, and the body frame 2 has a semi-double cradle shape. That is, the vehicle body frame 2 has a head pipe 3 at a front portion thereof.
The main frame 4 extends rearward and downward from the upper part of the
From the rear end of the main frame 4, a pair of left and right seat pillar tubes 6 extend downward.

On the other hand, there is provided a sub-frame 7 extending rearward and downward from a lower portion of the head pipe 3 and having a rear end connected to a lower end of the seat pillar tube. The auxiliary frame 7 includes a down tube 8 extending downward from the lower portion of the head pipe 3, and a pair of left and right lower frames 9, which extend downward from the lower end of the down tube 8 and then bend rearward. The front end of the lower frame 9 is screwed to the lower end of the down tube 8 by bolts 10.

A front fork 11 is supported on the head pipe 3 so as to be steerable. That is, the front fork 11 has a steering shaft inserted into the head pipe 3, and the steering shaft is rotatable around the axis of the head pipe 3. An upper bracket is attached to the upper end of the head pipe 3.
12 is attached, and a lower bracket 13 is attached to a lower end. A pair of left and right fork pipes 14 and 14 are supported by the upper bracket 12 and the lower bracket 13, and a front wheel 15 is supported between lower ends of the fork pipes 14 and 14, while a handle 16 is mounted on the upper bracket 12.
Is supported.

A rear arm 19 is pivotally supported at the lower part of the seat pillar tubes 6, 6 by a pivot shaft 18 so as to be vertically swingable. A rear wheel 20 is supported on the swing end of the rear arm 19. A shock absorber 21 is interposed between the upper portions of the seat pillar tubes 6, 6 and the rear arm 19 via a link mechanism 22.
23 is a road surface. The shock absorber 21 and the link mechanism 22 will be described later.

25 is a 1-cylinder 4-cycle engine.
Is located inside the body frame 2
Has been concluded. The intake port of this engine 25 has a carburetor
An air cleaner 27 is provided to clean external air sucked into the vaporizer 26.

An exhaust pipe 29 is connected to an exhaust hole of the engine 25. In this case, the engine 25 has two exhaust holes,
For this reason, the exhaust pipe 29 includes a pair of left and right front pipes 30, 30 connected to the respective exhaust holes. Also, this front tube 3
The rear ends of 0 and 30 are connected to each other by a collecting pipe 31.
Further, a rear tube 32 extending rearward from the collecting tube 31 is provided, and a rear end of the rear tube 32 is bent upward and a muffler 33 is attached to the end. In the above case, the rear tube 32 extends to the left of the lower portion of the engine 25 and along the left side surface of the lower frame 9 on the left side of the two lower frames 9,9.

A fuel tank 35 for supplying fuel to the carburetor 26 is provided. The fuel tank 35 has a pair of front tanks 36, 36 provided so as to sandwich the main frame 4 from the left and right,
The two front tanks 36, 36 are screwed together by bolts 36a and supported on the main frame 4.

The fuel tank 35 has a rear tank 38 behind the vehicle body frame 2, and the rear tank 38 is screwed to a stay 6 a protruding from the seat pillar tube 6. The rear tank 38 has an inverted U shape in a front view.

The engine 25 is provided with a drive sheave 41, while the rear wheel 20 is provided with a driven sheave 42, and a transmission chain 43 is wound around the both sheaves 41,42. The engine 25 operates by sucking outside air through the air cleaner 27 and the carburetor 26 and by sucking fuel from the fuel tank 35 through the carburetor 26. If the power of the engine 25 is transmitted to the rear wheels 20 via the transmission chain 43 and the like,
The running of the motorcycle 1 becomes possible.

The rear tank 38 supports a seat 44 on its upper surface. That is, the rear tank 38 is also a support bracket for the seat 44. In addition, 45 is a water tank.

In FIG. 3, the gap between the upper ends of the front tubes 30 is smaller than the diameter of the down tube 8.
For this reason, if both front pipes 30 and 30 are fixed to the collecting pipe 31, the down tube 8 becomes an obstacle and the front pipes 30 and 30 cannot be attached to and detached from the engine 25.

Therefore, as shown in FIG. 1, the upper end of each front tube 30 is
It is fitted to a flange 25a provided at each exhaust port of the engine 25 so as to be freely detachable, and is urged by a spring 30a to maintain this fitting.

On the other hand, the lower end of each front tube 30 is removably fitted into a pair of left and right fitting cylinders 31a, 31a formed at the front end of the collecting tube 31, and the fitting is maintained by springs 30b. Being energized.

When removing the front pipe 30 from the engine 25 side or the collecting pipe 31 side, first remove each spring 30a, 30b,
The fitting may be released and the front tube 30 may be removed.

Referring to FIGS. 1, 4 and 5, the connection between the seat pillar tubes 6, 6 and the lower frames 9, 9 will be described in more detail.

The lower end of the left seat pillar tube 6 of the seat pillar tubes 6 and 6 is connected to the right seat pillar tube 6.
Is shorter than the lower end. The lower end of the left seat pillar tube 6 and a portion slightly above the lower right end are connected by an upper cross pipe 46 serving as a cross member.

An arm 47 protrudes downward from the left end of the upper cross pipe 46 slightly toward the center in the vehicle width direction, and a lower end of the arm 47 and a lower end of the right seat pillar tube 6 are connected to a lower cross section. They are connected by a pipe 48.

The rear end of the right lower frame 9 of the lower frames 9, 9 is welded to the right end of the lower cross pipe 48. The rear end of the left lower frame 9 is screwed to the left side of the lower end of the arm 47 with a bolt 49.

In the above case, the rear end of the left lower frame 9 and the arm 47
A concave surface 9 a is formed at the rear end of the lower frame 9, while a convex surface 47 a is formed on the arm 47.
The concave surface 9a and the convex surface 47a are fitted with each other, whereby the lower rim 9 and the arm 47 are firmly connected.

Also, the upper cross pipe 46 and the lower cross pipe 48
A pair of left and right support plates 50, 50 are welded to the left and right central portions of the. The strength of the upper cross pipe 46 and the lower cross pipe 48 is improved by the support plates 50, 50.

A right footrest bracket 51 is screwed to a right end of the lower cross pipe 48 with a bolt 52, and a right footrest 53 is attached to the right footrest bracket 51.

On the other hand, a left footrest bracket 54 is fastened to the lower end of the arm 47 together with the rear end of the lower frame 9 by the bolt 49, and the left footrest bracket 54 is screwed to the same arm 47 by another bolt 49 '. It has been stopped. The left footrest bracket 54 protrudes leftward, and its protruding end is located above the rear tube 32, and its protruding end is located on the left side of the rear tube 32, and A left footrest 55 is attached to the end. Also, the left footrest bracket above
At the projecting end of 54, a nut 56 is welded slightly forward of the left footrest 55.

In the above case, since the arm 47 is provided closer to the center in the vehicle width direction than the left seat pillar tube 6, a recess 57 is formed below the left seat pillar tube 6 and to the left of the arm 47. Will be done. The rear tube 32 is fitted so as to pass through the recess 57, that is, the vertical dimension of the vehicle body is configured so that the vehicle width dimension is as small as possible.

1 to 5, a rectangular frame 60 having high rigidity is provided on the front surface of the sub-frame 7. This frame
The upper part of 60 is screwed to the down tube 8 by a pair of left and right bolts 61, 61, and the lower part of the upper frame body 60 is screwed to the lower left and right frames 9, 9 by a pair of left and right bolts 62, 62.

64 is an engine guard. The engine guard 64 is a flat U-shaped plate in a front view, and includes a bottom plate 65 and left and right side plates 66 and 66. The engine guard 64 covers the left and right lower frames 9, 9 and the engine 25 from below, and the left side of the engine guard 64 extends to the left to cover the lower surfaces of the collecting pipe 31 and the rear pipe 32. ing. For this reason, the engine guard 64 protects the collecting pipe 31 and the rear pipe 32 together with the engine 25.

A pair of left and right brackets 64a, 64a are welded to the front end of the engine guard 64, and the brackets 64a are firmly fastened together with the frame body 60 to the left and right rear tubes 9, 9 by the bolts 62, 62 described above. On the other hand, a projecting piece 67 is integrally formed on the right side plate 66 at the rear of the engine guard 64, and is screwed to the right footrest bracket 51 with a bolt 68.

A projecting piece 69 is integrally formed with a left side plate 66 at the rear of the engine guard 64, and is fastened by a bolt 70 screwed into a nut 56 provided on the left footrest bracket 54. That is, according to this configuration, the collecting pipe
The left end of the engine guard 64 extending so as to cover the lower surface of the rear foot pipe 31 and the rear pipe 32 and the protruding end of the left footrest bracket 54 are connected to each other by bolts 70. The guard 64 reinforces each other to improve the strength.

In the above case, the left end of the engine guard 64 and the left footrest bracket 54 both sandwich the rear tube 32 from above and below, so that the two cooperate with each other to form a frame-like structure. Is further improved.

In addition, a large number of through holes 71 are formed in the bottom plate 65,
The through hole 71 is provided for measuring the engine guard 64.

1 and FIGS. 4 to 7, the engine 25 is fastened to the body frame 2 as follows. That is, the front part of the crankcase 73 of the engine 25 is bolted to the bracket 74 screwed to the down tube 8.
It is screwed by. Meanwhile, the crankcase
The rear part of the power transmission case 77 connected to 73 is supported by the seat pillar tubes 6, 6 by the pivot shaft 18, and the lower rear end of the power transmission case 77 is connected to the support plates 50, 50.
And is screwed to the front of the support plates 50, 50 with bolts 78.

A part of the left side surface of the crankcase 73 protrudes laterally, and a flywheel magneto is housed inside the protruding portion 73a. Then, the projecting portion 73a
Is located inside the engine guard 64 in plan view.

Also, a part of the right side surface of the power transmission case 77 projects sideward, and the engine 25
A clutch for connecting and disconnecting power from the drive chain wheel 41 side is housed. The upper projecting portion 77a is also located inside the engine guard 64 in plan view.

Further, on the left side of the power transmission case 77, a change pedal 80 for speed change switching is pivotally supported so as to be vertically rotatable, and the front end of the change pedal 80 is a foot portion 80a. Then, when the foot on the left footrest 55 is stepped on the stepped portion 80a, a shift operation is performed. The change pedal 80 is located more inward in the vehicle width direction than the left end of the engine guard 64 in plan view, except for a small part of the foot portion 80a.

A brake pedal 82 is pivotally supported on the right seat pillar tube 6 by a pivot shaft 83 so as to be vertically rotatable. The front end of the brake pedal 82 is a foot step 82a. Then, the foot on the right footrest 53 is
Is operated by the brake provided on the rear wheel 20. The brake pedal 82 also has an engine guard 6 in plan view, except for a small part of the foot portion 82a.
4 is located inward of the right end of the vehicle in the vehicle width direction.

That is, the above-mentioned projecting portions 73a, 73a, the change pedal 8
By arranging the brake pedal 82 and the brake pedal 82 inside the left and right ends of the engine guard 64, the engine guard 64 sufficiently protects each device.

In addition, the water tank 45 is screwed to a front portion of the side plate 66 by a lower bolt 45a. At this time, this bolt 45
a is screwed to a nut 45b welded to the inner surface of the side plate 66.

6 and 7, the shock absorber 21 and the link mechanism 22
Will be described in more detail.

The shock absorber 21 is a telescopic hydraulic cylinder damper 84.
And a spring 85 that urges the damper 84 in a direction to extend the damper 84. The upper end of the damper 84 is connected to a cross pipe 86 extending over the upper ends of the seat pillar tubes 6, 6, by a first support shaft 87.
Is pivoted by

On the other hand, a link mechanism 22 is a main link pivotally supported by a second support shaft 88 at the rear of the support plates 50, 50 so as to be vertically rotatable.
A lower end of the damper 84 is pivotally supported by a third support shaft 90 at a pivot end of the main link 89. A pair of left and right connecting links 91 are pivotally supported by a fourth support shaft 92 at the front and rear halfway of the main link 89, and the rotating ends of the connecting links 91 and 91 are connected to a cross pipe 93 attached to the rear arm 19. Is pivotally supported by a fifth support shaft 94.

Thus, the shock absorber 21 buffers an impact that is transmitted from the road surface 23 to the vehicle body frame 2 through the rear wheel 20 and the rear arm 19.

At this time, the link mechanism 22 operates as follows.
That is, when the rear wheel 20 receives an impact from the road surface 23 and the rear arm 19 rotates upward while the motorcycle 1 is traveling, the link mechanism 22 causes the damper 84 to rotate as the rear arm 19 rotates upward.
Is increased non-linearly, thereby improving the ability of the rear wheel 20 to follow the road surface 23.

In the above case, the support plates 50, 50 support the engine 25 at the front and support the link mechanism 22 at the rear, so that the support plates 50, 50 are effectively used.

2, 8, and 9, reference numeral 96 denotes a side stand. The side stand 96 is pivotally supported by the seat pillar tube 6 by a pivot shaft 97 so as to be vertically rotatable. While the motorcycle 1 is traveling, the motorcycle 1 is maintained in a posture rotated upward as shown by a solid line in FIGS.
In this position, the rotation end side of the side stand 96 is located below the rear tube 32 in plan view as shown in FIG. In other words, the unused side stand
The 96 does not protrude outside the body, preventing it from disturbing the rider.

On the other hand, when parking, the motorcycle 1 is pivoted downward to incline the vehicle body so that the lower end thereof is installed on the road surface 23, as shown in the imaginary line in the improved drawing and in FIG. Can be independent on top.

(Effects of the Invention) According to the present invention, one side of the engine guard is extended so as to cover the lower surface of the exhaust pipe located on the lower side of the engine, while the protruding end side of the footrest bracket is attached to the exhaust pipe. And the extension of the engine guard is connected to the protruding end of the footrest bracket, so that the exhaust pipe can be protected with a simple configuration by using the engine guard.

In the above case, the extension on one side of the engine guard and the protruding end of the footrest bracket are connected to each other, and both the extension of the engine guard and the footrest bracket sandwich the exhaust pipe from above and below. ,
Both of them have a frame-like structure so that their strength can be effectively improved. Moreover, in this case, since the strength can be improved without providing a separate reinforcing member, the strength can be improved by a simple configuration.

[Brief description of the drawings]

1 shows an embodiment of the present invention. FIG. 1 is a partially enlarged side view of FIG. 2, FIG. 2 is an overall side view of a motorcycle, FIG. 3 is a front view, and FIG. 4 is a plan view of FIG. FIG. 5 shows V in FIG.
FIG. 6 is a partial enlarged cross-sectional view of FIG. 2;
7 is a sectional view taken along line VII-VII of FIG. 6, FIG. 8 is a plan view of the side stand when not used, and FIG. 9 is a rear view of the side stand when used. 1 ... motorcycle, 2 ... body frame, 25 ... engine, 29 ... exhaust pipe, 54 ... left footrest bracket (footrest bracket), 55 ... left footrest (footrest), 64 ... engine guard.

Claims (1)

(57) [Claims] An engine is mounted on a vehicle body frame, and an exhaust pipe extending rearward from the engine passes through a lower side of the engine, while a footrest bracket for supporting a footrest is positioned on a lower side of the engine. Protrude outward from a part of the body frame, and
In the lower body structure of a motorcycle in which an engine guard covering the lower surface of the engine is attached to the body frame, one side of the engine guard is extended so as to cover the lower surface of the exhaust pipe located on the lower side of the engine, On the other hand, a lower body structure of a motorcycle in which a projecting end side of a footrest bracket is positioned above the exhaust pipe, and an extension of the engine guard is connected to the projecting end of the footrest bracket.