JPH07315272A - Foot rest vibration damping structure for motorcycle - Google Patents

Abstract

PURPOSE:To reduce vibration in a foot rest part without greatly increasing the weight of a vehicle by means of an inexpensive constitution in a motorcycle. CONSTITUTION:In a motorcycle provided with a foot rest bar 4, which laterally extends below a crank case 2a and is curved along a magneto side cover 2L and a clutch side cover 2R and slightly rises, and from the upper ends of these rising parts 4aL, 4aR, the foot rest bar 4 is curved toward both right and left sides so as to form foot rest parts 4bL, 4bR, while a cylindrical rubber damper 6 which is brought into contact with the magneto side cover 2L is installed in the upper end of the rising part 4aL. In this way, vibration in the foot rest part 4bL is absorbed by the rubber damper 6 so as to be attenuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a footrest vibration isolation structure for a motorcycle.

[0002]

2. Description of the Related Art Generally, a motorcycle is equipped with a footrest structure having a footrest portion. An example of a conventional footrest structure is shown in FIG. The footrest structure shown in FIG. 6 extends leftward and rightward below a crankcase a of a motorcycle, bends upwards, and further bends leftward and rightward in a substantially rhomboidal shape footrest bar b (the right portion is shown in the figure). Is fixed to the lower surface a1 of the crankcase with screws c or the like, and the left and right ends of the footrest bar b are used as footrests d. An elastic rubber such as rubber is fitted on the foot rest d. In this type of footrest structure, since the span from the fastening portion (position of the screw c) of the footrest bar b to the footrest portion d is long, there is a problem that the footrest portion d largely vibrates due to engine vibration or the like. There is a possibility that the footrest portion d may resonate, especially when the normal engine speed matches the natural frequency of the footrest portion d.

Therefore, conventionally, as shown in FIG. 7, a rib e is formed on the bent portion of the footrest bar b to increase the rigidity of the footrest bar b, or a weight is attached to the end portion of the footrest portion d. By doing so, the natural frequency of the footrest d is set outside the normal engine speed range of the engine to reduce the vibration of the footrest d.

[0004]

However, when the space between the bent portion of the footrest bar b and the clutch cover f is narrow, there is a disadvantage that the space for providing the rib e cannot be sufficiently secured. Further, in the case where a weight is attached to the end of the footrest portion d, the weight of the weight may increase the weight of the vehicle and increase the cost.

The present invention has been made in view of the problems of the conventional footrest structure, and prevents the footrest of a motorcycle from reducing vibration of the footrest portion with an inexpensive structure without significantly increasing the vehicle weight. The purpose is to provide a vibration structure.

[0006]

The present invention has the following constitution in order to achieve the above object. That is, the invention of claim 1 extends leftward and rightward below the engine case, bends and rises along both left and right side surfaces of the engine case, and further bends leftward and rightward at the upper end of the rising portion. In a motorcycle having a footrest bar in which left and right footrest portions are formed, an elastic body that is in contact with the engine case is attached to a portion of the footrest bar that is on the vehicle inner side of the footrest portion. It is a footrest anti-vibration structure for motorcycles.

According to a second aspect of the present invention, there is provided the footrest anti-vibration structure for a motorcycle according to the first aspect, wherein the elastic body is in contact with a side surface of the engine case.

[0008]

According to the first aspect of the present invention, the elastic body contacting the engine case regulates the maximum displacement point of the vibration of the footrest portion to reduce the amplitude. Further, the vibration energy of the footrest is absorbed by the elastic body, and the vibration of the footrest is damped. In addition, since the vibration mode of the footrest can be changed by adjusting the material of the elastic body and the contact state, the natural frequency of the footrest is set outside the engine normal rotation speed range and Resonance can be prevented.

According to the second aspect of the invention, since the elastic body is brought into contact with the side surface of the engine case, the elastic body can be positioned at the footrest bar portion facing the side surface of the engine case. On the other hand, if the elastic body is provided at the footrest bar portion below the engine case, it is necessary to assemble the elastic body together with the engine, the footrest bar, etc., which makes the assembly work troublesome.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a footrest vibration isolation structure for a motorcycle according to the present invention will be described below with reference to the drawings. Figure 1
2 is a front view showing the entire footrest structure according to the present embodiment, FIG. 2 is a front view showing the footrest vibration isolation structure according to the present embodiment, and FIG. 3 is an exploded view of the footrest vibration isolation structure according to the present embodiment. It is a perspective view. Further, FIG. 4 is a front view showing a footrest anti-vibration structure according to a modification, and FIG.
FIG. 8 is an exploded perspective view of a footrest vibration isolation structure according to a modification.

As shown in FIG. 1, the engine 2 according to this embodiment includes a crankcase 2a including a crankshaft, a transmission, etc., and a magnet side cover 2L for closing the left side surface and the right side surface of the crankcase 2a. And a clutch side cover 2R.

The footrest structure has a crankcase 2a.
It extends left and right below (corresponding to the engine case) and also has a magneto side cover 2L and a clutch side cover 2R.
It bends along (corresponding to the left and right side surfaces of the engine case) and rises slightly obliquely upward, and further bends to the left and right sides at the upper ends of the rising portions 4aL, 4aR to form the left and right footrest portions 4bL, 4bR. The formed footrest bar 4 has a substantially elliptical shape.

The footrest bar 4 is a crankcase 2
It is attached to the lower part of a through a plate 8. The plate 8 has a shape in which the left and right side portions are bent upward. The bent portions 8a are fastened to the left and right side surfaces of the lower portion of the crankcase 2a with screws 10 and the like, and the upper surface of the plate 8 is crankcase 2a. It is welded to the bottom surface. An elastic rubber is fitted to the footrests 4bL and 4bR as in the conventional case. In addition, since the muffler 12 extending along the front-rear direction passes below the portion of the engine 2 slightly to the left of the central portion,
To the left of the center of footrest bar 4,
A curved escape 4c is formed above the muffler 12.

The footrest anti-vibration structure according to this embodiment is
As shown in FIGS. 2 and 3, in the vicinity of the upper end of the left rising portion 4aL of the footrest bar 4 (an example of a portion inside the vehicle with respect to the footrest portion), on the magnet side cover (an example of a side surface of the engine case) 2L. A cylindrical rubber damper (an example of an elastic body) 6 that abuts is attached, and a substantially inverted T-shaped attachment piece 14 that is welded near the upper end of the rising portion 4aL and projects rearward, and this attachment piece. 14 and a plate 20 that is fastened with bolts 16 and nuts 18 to the inner surface of the plate 20. The plate 20 has a shallow cylindrical shape. And a damper receiver 24 that holds the outer peripheral surface of the.

The rubber damper 6 is a magnet side cover 2
It is assembled by being slightly compressed in the axial direction between L and the damper receiver 24, and thereby elastically abuts the magnet side cover 2L.

According to the present embodiment having the above-mentioned structure, the rubber damper 6 which abuts on the magneto side cover 2L.
However, the maximum displacement point of the vibration of the footrest 4bL is restricted to reduce the amplitude. Further, the vibration energy of the footrest 4bL is absorbed by the rubber damper 6, and the vibration of the footrest 4bL is attenuated. Particularly, in this embodiment, the rubber damper 6 is located very close to the footrest portion 4bL, so that the damping effect is great. In addition, since the vibration mode of the footrest 4bL can be changed by adjusting the material of the rubber damper 6 and the contact state (elasticity at the time of assembling), the natural frequency of the footrest 4bL can be changed to the engine normal rotation speed. It can be out of several ranges, which can prevent the footrest 4bL from resonating.

Therefore, according to this embodiment, the vibration of the footrest portion 4bL can be greatly reduced as compared with the conventional case. As described above, the relief 4c of the muffler 12 is formed in the footrest bar 4, and the dimension along the axis of the footrest bar 4 is lengthened by the relief 4c.
If the conventional footrest structure is used, the vibration of the footrest portion 4bL may increase due to the increased dimension. However, according to the present embodiment, even in such a case, the footrest portion 4bL is prevented by the rubber damper 6. Vibration of 4bL can be reduced.

Further, the rubber damper 6 can be assembled only by passing the bolt 16 from the side of the vehicle through the mounting piece 14 and the hole of the plate 20 and screwing the bolt 16 into the nut 18. Therefore, even after the engine 2 and the footrest bar 4 are assembled to the vehicle body, the rubber damper 6 can be easily attached to the footrest bar 4, so that the assembly work of the rubber damper 6 can be easily performed.

On the other hand, it is conceivable that a vibration-proof rubber or the like is provided at a portion of the footrest bar 4 located below the engine 2, but in this case, the vibration-proof rubber or the like is provided together with the engine 2 and the footrest bar 4. Since it is necessary to assemble, the assembly work is troublesome.

Further, according to this embodiment, the rubber damper 6
Does not need to be accurately aligned on the side surface of the magnet side cover 2L, and also in this respect, the assembling work of the rubber damper 6 is easy. Further, since the number of parts is small, the vibration damping structure can be constructed at a low cost and the vehicle weight is not significantly increased.

The present embodiment is a preferred embodiment of the present invention, and the technical scope of the present invention is not limited to this embodiment. For example, the footrest bar 4 of the rubber damper 6
The position of attachment to is not limited to the position shown in this embodiment. The point is that it is a part of the footrest bar 4 inside the vehicle with respect to the footrests 4bL and 4bR, as long as the rubber damper 6 comes into contact with the case body constituting the engine 2. Therefore, even if it is provided at the portion of the footrest bar 4 facing the lower surface of the engine 2, it is within the technical scope of the present invention. In this case, at least the footrest 4bL (4
It is possible to obtain the effect that the vibration of bR) is reduced as compared with the conventional case.

In the present embodiment, the left footrest portion 4b is also provided.
The anti-vibration structure of the present invention is adopted only for L, and the right foot rest 4
The rib 26 (see FIG. 1) is formed on the bR, but the present invention is not limited to this, and of course, a vibration damping structure using an elastic body may be provided near the right footrest 4bR. Good (see FIGS. 4 and 5).

4 and 5 shows a modification of the present embodiment as the vibration isolation structure on the right side, which is welded to a portion of the footrest bar 4 slightly inside the vehicle from the footrest portion 4bR. An L-shaped mounting piece 28, a plate 34 fastened to the mounting piece 28 by a welding nut 30 and a bolt 32 provided on the inner side surface of the mounting piece 28, and an inner side of the vehicle fixed to the inner side surface of the plate 34. Bar 36 protruding toward and a brim 38 on this bar 36.
And a rubber tamper 42 having a recess 42a fitted to the projection 40 on one end surface and the other end surface abutting on the clutch side cover 2R.

[0024]

As described above, according to the first aspect of the invention, the maximum displacement point of the vibrating foot rest is regulated to reduce the amplitude and the vibration of the foot rest is damped. Moreover, since the resonance of the footrest portion can be prevented, the vibration of the footrest portion can be reduced.
Further, since the number of parts is small, the vibration damping structure can be constructed at low cost and the vehicle weight is not significantly increased.

According to the second aspect of the present invention, since the elastic body can be assembled to the footrest bar from the side of the vehicle, the elastic body can be easily attached to the footrest bar even after the engine case and the footrest bar are assembled to the vehicle body. You can Therefore, the work of assembling the elastic body can be easily performed.

[Brief description of drawings]

FIG. 1 is a front view showing the entire footrest structure according to the present embodiment.

FIG. 2 is a front view showing a footrest anti-vibration structure according to the present embodiment.

FIG. 3 is an exploded perspective view of the footrest anti-vibration structure according to the present embodiment.

FIG. 4 is a front view showing a footrest anti-vibration structure according to a modified example of the present embodiment.

FIG. 5 is an exploded perspective view of a footrest anti-vibration structure according to a modified example of this embodiment.

FIG. 6 is a front view showing a conventional footrest structure.

FIG. 7 is a front view showing a conventional footrest anti-vibration structure.

[Explanation of symbols]

2 Engine 2a Crankcase (equivalent to engine case) 2L Magneto side cover (equivalent to left side of engine case) 2R Clutch side cover (equivalent to right side of engine case) 4 Footrest bar 4aL, 4aR Rise 4bL, 4bR Foot rest Part 6,42 Rubber damper (an example of elastic body)

Claims (2)

[Claims] 1. A left and right footrest that extends left and right below an engine case, bends and rises along both left and right side surfaces of the engine case, and further bends left and right at the upper end of the rising portion. A motorcycle having a footrest bar in which a portion is formed, characterized in that an elastic body that is in contact with the engine case is attached to a portion of the footrest bar that is on the vehicle inner side of the footrest portion. Foot rest anti-vibration structure. 2. The footrest vibration isolation structure for a motorcycle according to claim 1, wherein the elastic body is in contact with a side surface of the engine case.