JP3111712B2 - Exhaust system for motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a motorcycle. More specifically, the present invention relates to a suspension portion for suspending an exhaust device of a motorcycle on a vehicle body.

[0002]

2. Description of the Related Art The appearance of a motorcycle is substantially symmetrical with respect to a vertical plane (hereinafter, simply referred to as a "median plane") including a frame center line of the motorcycle.
Each component is attached to a portion serving as a base such as a frame as a vehicle body. For example, as shown in FIG. 5, a plurality of exhaust pipes e connected to an engine (not shown)
_1, e ₂ ... and, the plurality of exhaust pipes e _1, e ₂
A plurality of mufflers m ₁ connected to an appropriate one of ...
m ₂ , the exhaust system a of the motorcycle also has a median plane s
(Since FIG. 5 is a plan view, it is shown by a dashed line.) It is attached to a frame (not shown) via suspension members q, q. still,
In FIG. 5, the exhaust pipe e ₁ ,
The side where e ₂ is located is the front, the upper side is the right side and the lower side is the left side with respect to the median plane S. The same applies hereinafter.

However, when it comes to the engine,
For reasons of the mechanism, as shown in FIG. 6, generally, components having relatively large mass and rotating, such as the clutch k and the primary gear p, among the engine components (hereinafter, simply referred to as “rotating components”). , Are concentrated on the right side of the vehicle.
Therefore, the engine is driven by the clutch k and the primary gear p.
For example, the weight, components, and shape are not symmetrical between the right side where parts having a large mass are concentrated and the left side where they are not. Therefore, combined with the fact that the weight, the components and the shape are not symmetric, the engine has different vibrations on the left and right sides, and in particular, the vibration on the right side, which has many rotating parts such as the clutch k and the primary gear p, is on the left side is more than.

Accordingly, the exhaust pipes e ₁ and e ₂ connected to the right side of the engine and the muffler m ₁ are connected to the exhaust pipes e ₃ and e ₄ connected to the left side of the engine and the muffler m _1.
Vibrates more than _two . And, of the right exhaust pipes e ₁ and e ₂ and the muffler m ₁ , the suspension part q of the muffler m ₁ located at the free end is connected to the frame so that stress concentrates on the part. Become. Therefore, it is necessary to improve the durability of the connection portion by adding a reinforcing member (not shown) in addition to the suspension portion q. However, in this case, it takes time to assemble by the amount of the reinforcing member, and also causes an increase in cost.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an exhaust pipe and a muffler on the side of a large amount of vibration transmitted from an engine. Even without adding a reinforcing member, the durability of the exhaust pipe and the muffler on the side with much vibration transmitted from the engine can be improved by using only the suspension member, and the assembling time to the vehicle body is short, An object of the present invention is to provide a motorcycle exhaust device that can reduce costs.

[0006]

An exhaust system for a motorcycle according to the present invention solves the above-mentioned problems and is as follows. That is, the exhaust device for a motorcycle according to the present invention includes a plurality of exhaust pipes and a plurality of mufflers connected to an appropriate one of the plurality of exhaust pipes, and is suspended from a vehicle body via a suspension unit. In a motorcycle exhaust device arranged substantially symmetrically with respect to the median plane of the motorcycle, the weight distribution of the engine is large due to the structure of the parallel multi-cylinder engine to which the exhaust device is connected, and An exhaust pipe and a muffler located on one side with respect to the median plane connected to the side where the rotating parts are concentrated, and connected to the side where the weight distribution is small and the rotating parts are not concentrated on the median plane Of the exhaust pipe and muffler located on the other side with respect to the median plane, the side where the weight distribution is large and the rotating parts are concentrated That exhaust pipe and the muffler and the weight distribution was shown relationship the suspension unit to a muffler and only according to the side that does not concentrate in the small and rotating parts.

[0007]

According to the exhaust device for a motorcycle of the present invention, the weight distribution of the engine is large at the median plane, the exhaust pipe and the muffler connected to the side where the rotating parts are concentrated, and the weight distribution is small at the median plane. Of the exhaust pipe and muffler connected to the side where the rotating parts do not concentrate,
Since the suspension is associated only with the exhaust pipe and the muffler on the side where the weight distribution is large and where the rotating parts are concentrated, and the muffler on the side where the weight distribution is small and where the rotating parts are not concentrated, the exhaust device is separated from the median plane. On one side and the other side, the number of places that are suspended from the vehicle body, that is, the number of places that are supported, is different. One side is related to an exhaust pipe and a muffler, and the other side is related to a muffler. Supported in one place.

Therefore, one side to which large vibration is transmitted from the engine is supported more than the other side to which small vibration is transmitted. Therefore,
On one side, the vibration is suppressed by the number of supported portions, and on the other side, the vibration is not suppressed more than that of the one side. Therefore, in the exhaust system,
Vibration is no longer symmetrical between one side with many suspension parts and the other side with few suspension parts, and the vibration on one side with many suspension parts is offset by the vibration on the other side with few suspension parts . Therefore, on one side and the other side of the exhaust device, the stresses become almost equal.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an exhaust system for a motorcycle according to the present invention. 1 is an overall side view showing a state in which the exhaust device of the motorcycle of the present invention is mounted on the motorcycle, FIG. 2 is a plan view of the exhaust device of the motorcycle of the present invention, and FIG. 3 is a graph showing vibration in a muffler mount. FIG. 4 is a graph showing the vibration in the case of the prior art for comparison with FIG.

The motorcycle 2 has a frame 4 as a skeleton. The frame 4 is provided with a front wheel 6 and a rear wheel 8 before and after it. Between the front wheel 6 and the rear wheel 8, a parallel multi-cylinder engine 10 is attached to the frame 4 by fixing means (not shown).

An exhaust device 12 for a motorcycle according to the present invention is connected to the parallel multi-cylinder engine 10. Also,
In the parallel multi-cylinder engine 10, due to its structure, rotating parts having a relatively large mass, such as a clutch and a primary gear (not shown), are concentrated on the right side of a median plane described later. Therefore, the weight distribution of the right side of the parallel multi-cylinder engine 10 is larger than that of the left side.

The exhaust device 12 of the motorcycle includes a pipe portion 1.
4, a muffler section 16, and metal clamps 18, 18 connecting the pipe section 14 and the muffler section 16, and are suspended on the frame 4 via a suspension section described later.

The pipe section 14 includes four exhaust pipes # 1 to # 4 and a pipe collecting section 22. Front end 23 _{1-23 4} of the exhaust pipe ♯1~♯4 via the flange 27 _{1-27 4} are respectively connected to the cylinder or cylinder head 24 of the parallel multi-cylinder engine 10, the rear wheel side end, the pipe It is connected to the collecting unit 22.

On the rear wheel side of the pipe gathering portion 22, there are formed bifurcated branch paths 28 ₁ and 28 ₂ . Fork 28
₁ and 28 ₂ are connected to the muffler section 16 via fasteners 18 and 18.
Are connected to the respective mufflers 16 ₁ and 16 ₂ . by this,
The exhaust pipes # 1 and # 2 and the muffler 16 _1, and the exhaust pipes # 3 and # 4 and the muffler 16 ₂ ,
It is integrally connected through a branch passage 28 ₁ and the branch passage 28 _{and second} pipe gathering portion 22, respectively. Then, these exhaust pipes # 1 · # 2 and the muffler 16 ₁ and an exhaust pipe # 3 · # 4 and the muffler 16 ₂ is formed symmetrically to a median plane s including the frame centerline 32 as the boundary.

Thus, the exhaust pipes # 1 and # 2 integrated with the muffler 16 via the pipe collecting section 22 are integrated.
_{The reference} numeral ₁ denotes an exhaust pipe # 3, # 4 connected to the right side of 10 cylinders or a cylinder head 24 of the parallel multi-cylinder engine to which the exhaust device 12 is connected, and also integrated via a pipe collecting section 22. And muffler 16
₂ is connected to the left part of the cylinder or cylinder head 24.

[0016] Exhaust pipe bracket 34 and the muffler mount 36 ₁ a as suspension unit, there is located on the right side of the median plane S, the branch passage 28 ₁ of the base portion near the upper surface and the muffler 16 ₁ of each pipe gathering portion 22 of which provided substantially at the center than the previous top, these exhaust pipe bracket 34 and the muffler mount 36 ₁ are respectively combined with dampers 38 and the support 40 ₁ screwed into an appropriate position of the frame 4. Thus, the pipe collecting unit 2
By fixing the frame 4 via the second branch passage 28 ₁ in the exhaust pipe bracket 34 of the base portion near the upper surface, also be secured to the frame 4 via the muffler mount 36 ₁ a substantially central than the previous upper surface of the muffler 16 ₁ By
Exhaust Pipe # 1 · # 2 and the muffler 16 ₁ is suspended on the frame 4.

Muffler mount 36 as a suspension
₂ is for the left of the median plane S, are provided on from the inside and is earlier than the upper surface of the muffler 16 _1.
The muffler mount 36 ₂ is combined with the support 40 ₂ screwed into an appropriate position of the frame 4. In addition, a suspension provided on the side where the exhaust pipes # 3 and # 4 are located with the median plane S as a boundary in the pipe collecting part 22 and on the side where the exhaust pipes # 1 and # 2 are located with the median plane S as a boundary. There is no equivalent to the exhaust bracket 34 as a part. Thus, the exhaust pipe # 3
· # 4 in the form not suspended, also the muffler 16 ₂ is suspended is suspended in the muffler mount 36 ₂ as suspension unit to the frame 4.

The exhaust device 12 is mounted on the vehicle body as described above.

The exhaust device 12 for a motorcycle constructed as described above has the following functions and effects. That is, with the exhaust pipes # 1 and # 2 and the muffler 16 ₁ connected to the right side where the weight distribution of the parallel multi-cylinder engine 10 is large and the rotating parts are concentrated on the median plane S, Exhaust pipe connected to the left side where weight distribution is small and rotating parts are not concentrated.
3. Exhaust pipe # 1 on the right side where the weight distribution is large and the rotating parts are concentrated among muffler 16 ₂ and # 4
· A ♯2 and muffler 16 _1, only the muffler 16 ₂ according to the left which is not concentrated small rotating parts weight distribution, exhaust pipe bracket 34 is a suspension part, respectively, is provided with the muffler mount 36 ₁ and the muffler mount 36 ₂ On the right side and the left side of the exhaust device 12 with respect to the median plane s, the number of places to be suspended from the vehicle body, that is, the number of supported places is different, the right side is two places related to the exhaust pipe and the muffler, and the other side is It is supported at one place related to the muffler.

Therefore, the right side, which is one side to which large vibration is transmitted from the engine, is supported more than the left side, which is the other side to which small vibration is transmitted. Therefore, on the right side, the vibration transmitted from the engine is suppressed by the number of supported portions, and on the left side, the vibration transmitted from the engine is not suppressed by the number of supported portions. . Therefore, in the exhaust device, the vibration is not symmetrical between the right side and the left side where there are many suspension portions with respect to the median plane, and the vibration on the right side where there are many suspension portions is canceled by the left side vibration where there are few suspension portions. Therefore, the stress becomes almost equal between the right side and the left side of the exhaust device.

[0021] Figure 3 is a graph showing the vibration test in the muffler mount 36 _1, the vertical axis denotes the acceleration G (unit 9.8 m / sec ^2), revolutions per minute on the horizontal axis the engine RPM Is shown. Further, the tightening torque of the clamp 18 is 150 kg · m, the natural frequency of the primary muffler 16 ₁ muffler mount 36 ₁ is attached are those conducted under conditions that 300 Hz. In FIG. 3, D ₁ , D _2, and D ₃ indicate vibrations in the front-rear, left-right, and up-and-down directions, respectively, and D ₄ indicates vibration in the above three directions.

FIG. 4 is data showing vibrations obtained in the prior art under the same conditions as those of the present invention.
As is clear from the comparison between the two figures, it is understood that the improvement is considerably improved as compared with the prior art.

[0023]

According to the exhaust system for a motorcycle of the present invention,
The stress is substantially equal between one side and the other side of the exhaust device with respect to the median plane S. Therefore, it is possible to improve the durability of the exhaust pipe and the muffler on the side where the transmitted vibration is large by using only the suspension member without adding a reinforcing member to the exhaust pipe and the muffler on the side where the vibration transmitted from the engine is large. Can be. Furthermore, the time required for assembling to the vehicle body is short, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall side view showing a state in which a motorcycle exhaust device of the present invention is mounted on a motorcycle.

FIG. 2 is a plan view of the exhaust device of the motorcycle according to the present invention.

FIG. 3 is a graph showing vibration in a muffler mount on one side to which large vibration is transmitted from an engine.

FIG. 4 is a diagram showing vibration in the case of the conventional technique for comparison with FIG. 3;

FIG. 5 is a diagram showing a conventional technique.

FIG. 6 is a diagram for explaining a conventional technique.

[Explanation of symbols]

 2 Motorcycle 10 Parallel multi-cylinder engine 12 Motorcycle exhaust system 14 Pipe section 16 Muffler # 1-4 Exhaust pipe 32 Frame centerline 34 Suspension section 36 Suspension section S

Claims (1)

(57) [Claims] 1. A motorcycle having a plurality of exhaust pipes and a plurality of mufflers connected to an appropriate one of the plurality of exhaust pipes, being suspended from a vehicle body via a suspension portion, and In the exhaust system of a motorcycle which is arranged substantially symmetrically, the weight distribution of the engine is large at the median plane and connected to the side where the rotating parts are concentrated due to the structure of the parallel multi-cylinder engine to which the exhaust system is connected. The exhaust pipe and the muffler located on one side with respect to the median surface, and the weight distribution is small with the median surface as a boundary, and the other with respect to the median surface connected to the side where the rotating parts are not concentrated. Of the exhaust pipe and muffler located on the side where the weight distribution is large and the rotating parts are concentrated. The exhaust system for a motorcycle, wherein the suspension unit is related only to the muffler on the side where the weight distribution is small and the rotating parts are not concentrated.