JP3019658B2 - 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.

[0002]

2. Description of the Related Art In a conventional exhaust system for a motorcycle, it is necessary to consider the influence of exhaust heat when the exhaust system is mounted on the motorcycle. For this reason, the base end of the exhaust pipe extending from the engine is fixed to the cylinder head of the engine, and the silencer connected to the distal end of the exhaust pipe is supported on the vehicle body frame via the bracket. That is, the exhaust device is supported at a position away from the engine to avoid the influence of exhaust heat.

However, in the above-described mounting structure, since the supporting span becomes long and the rigidity of the silencer is not so large, the exhaust device is easily vibrated. As a result, the exhaust device may resonate due to the vibration of the engine, and this vibration may cause noise or damage to the exhaust device. This tendency is particularly remarkable when the engine rotates at high speed.

[0004] For this purpose, there is a type in which a dynamic balancer, which is means for reducing the vibration of the exhaust device, is provided on the exhaust pipe. This dynamic balancer prevents the exhaust device from vibrating by matching its resonance frequency range to the resonance frequency range of the exhaust device with respect to engine vibration.

[0005]

The elastic body provided inside the dynamic balancer needs to be cooled because its function deteriorates when the heat becomes high.

However, if a dynamic balancer is provided on the exhaust pipe, the traveling wind is heated by the exhaust pipe located in front of the dynamic balancer, so that the dynamic balancer is not efficiently cooled. Further, if the dynamic balancer is directly attached to the exhaust pipe, heat is transmitted to the dynamic balancer by the heat of the exhaust pipe. That is, the dynamic balancer does not function properly.

The present invention has been made in consideration of the above circumstances, and has as its object to provide an exhaust system for a motorcycle in which traveling wind is directly applied to a dynamic balancer.

Another object of the present invention is to provide an exhaust system for a motorcycle that reduces the heat of an exhaust pipe transmitted to a dynamic balancer.

[0009]

According to a first aspect of the present invention, there is provided an exhaust system for a motorcycle, comprising: an exhaust pipe extending from an engine; A muffler connected to the engine, a base end of the exhaust pipe is fixed to an engine, and the muffler is supported on a vehicle body frame via a bracket. In the front, a dynamic balancer is provided on the exhaust pipe between the lower part of the radiator and the lower end of the front opening of the cowling, and the exhaust pipe located immediately before the dynamic balancer is not obstructed by the traveling wind hitting the dynamic balancer. It is bent.

[0010] In order to solve the above-mentioned problem, the dynamic balancer is provided on the exhaust pipe via a bracket.
The bracket forms a traveling air passage between the bracket and the exhaust pipe.

[0011]

According to the present invention having the above-described structure, the exhaust pipe includes an exhaust pipe extending from the engine and a muffler connected to the exhaust pipe, and a base end of the exhaust pipe is fixed to the engine. In a motorcycle exhaust device supported on a body frame via a bracket, a dynamic balancer is provided on the exhaust pipe between a lower portion of a radiator and a lower end of a front opening of a cowling in front of an engine. In addition, since the exhaust pipe located immediately before the dynamic balancer is bent so that the traveling wind hitting the dynamic balancer is not obstructed, the traveling wind can be directly applied to the dynamic balancer.

Further, the dynamic balancer is provided on the exhaust pipe via a bracket, and since the bracket forms a running air passage between the bracket and the exhaust pipe, the heat of the exhaust pipe transmitted to the dynamic balancer is reduced. Can be done.

[0013]

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

FIG. 1 is a left side view showing an example of a motorcycle to which the present invention is applied.

In FIG. 1, the motorcycle 1 has a body frame 2, and an engine 3 is mounted at a lower center portion of the body frame 2.

At the front of a cylinder head 3a of the engine 3, four exhaust pipes 5 constituting an engine exhaust system 4 are provided.
5d are fixed, and these exhaust pipes 5a... 5d once extend forward and then bend downward, and then bend backward at the lower part of the engine 3 and converge two by two. It is further converged and extends rearward below the engine 3. A silencer 6 is connected to the end of the converged exhaust pipes 5a... 5d, and the silencer 6 is supported by the vehicle body frame 2 via a bracket (not shown).

A radiator 7 for cooling the engine cooling water is provided in front of the engine 3.
Is covered by the cowling 8 together with the engine 3 and the exhaust pipes 5a to 5d.

FIG. 2 is a left side view of the engine exhaust device 4, and FIG. 3 is a plan view of the engine exhaust device 4. FIG. 4 is a view of the engine exhaust device 4 as viewed from the front.

As shown in FIGS. 2, 3 and 4, on the exhaust pipe 5c between the lower part of the radiator 7 and the lower end of the front opening 8a of the cowling 8 in front of the engine 3, for example, A bracket 9 formed in a shape is provided so that its opening 9 a is directed in the traveling direction of the motorcycle 1, and forms a traveling air passage 10 between the exhaust pipe 5 c and the bracket 9. On the bracket 9, a dynamic balancer 11, which is means for reducing the vibration of the exhaust device 4, is provided.

As shown in FIG. 4, exhaust pipes 5a and 5b located in front of the dynamic balancer 11 are provided.
Is bent so as not to obstruct the flow of the traveling wind that strikes the dynamic balancer 11.

As shown in FIG. 5, the dynamic balancer 11 includes, for example, a disc spring 11c, 1 in which a balancer weight 11b is an upper and lower elastic body in a cylindrical container 11a.
1d. A bolt 11e as a means for fixing the container 11a to the bracket 9 is provided below the container 11a, and is fixed to the bracket 9 with a nut 12.

Next, the operation of this embodiment will be described.

In the exhaust device 4 of the motorcycle 1 configured as described above, the dynamic balancer 11
Is provided on the exhaust pipe 5c in front of the engine 3 and between the lower part of the radiator 7 and the lower end of the front opening 8a of the cowling 8, and the exhaust pipes 5a and 5b located in front of the dynamic balancer 11 correspond to the dynamic balancer 11. Since the vehicle is bent so as not to obstruct the flow of the traveling wind, the traveling wind directly hits the dynamic balancer 11 while the motorcycle 1 is traveling, so that the dynamic balancer 11 can be efficiently cooled.

Further, since the dynamic balancer 11 is attached to the exhaust pipe 5c via the bracket 9, the dynamic balancer 11 is efficiently cooled by the traveling wind passing through the traveling wind passage 10, and the exhaust transmitted to the dynamic balancer 11 from the exhaust pipe 5c. The heat of the pipe can be reduced.

As described above, the dynamic balancer 1
Disc spring 11 which is an elastic body provided in one container 11a
Since the exhaust heat transmitted to c and 11d is reduced, its function is not reduced.

Further, since the exhaust device 4 includes the dynamic balancer 11, the amplitude of the exhaust device 4 at the time of resonance is reduced, so that the overall strength of the exhaust device 4 can be reduced, and the exhaust pipes 5a. There is no need to attach a reinforcing plate to the connection between the muffler and the muffler 6 or increase the thickness of the pipe where stress is concentrated, so that the weight of the exhaust device 4, that is, the body of the motorcycle 1 can be reduced.

[0027]

As described above, according to the motorcycle exhaust system of the present invention, the exhaust system includes the exhaust pipe extending from the engine and the muffler connected to the exhaust pipe. In a motorcycle exhaust system in which an end is fixed to an engine and the muffler is supported on a vehicle body frame via a bracket, the exhaust system includes a radiator lower part, a cowling front opening lower end, and a cowling front part. A dynamic balancer is provided on the exhaust pipe during the period, and the exhaust pipe located immediately before the dynamic balancer is bent so that the traveling wind hitting the dynamic balancer is not obstructed, so that the traveling wind is directly applied to the dynamic balancer. Can be.

Further, the dynamic balancer is provided on the exhaust pipe via a bracket, and since the bracket forms a running air passage between the bracket and the exhaust pipe, the heat of the exhaust pipe transmitted to the dynamic balancer is reduced. Can be done.

[Brief description of the drawings]

FIG. 1 is a left side view of a motorcycle showing one embodiment of a motorcycle exhaust device according to the present invention.

FIG. 2 is a left side view of the engine exhaust device.

FIG. 3 is a plan view of the engine exhaust device.

FIG. 4 is a front view of the engine exhaust device.

FIG. 5 is a sectional view showing a structure and a bracket of the dynamic balancer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 3 Engine 4 Exhaust device 5a ... 5d Exhaust pipe 6 Silencer 7 Radiator 8 Cowling 8a Cowling opening 9 Bracket 10 Running air passage 11 Dynamic balancer

Claims (2)

(57) [Claims] 1. An exhaust pipe extending from an engine, and a muffler connected to the exhaust pipe. A base end of the exhaust pipe is fixed to the engine, and the muffler is connected to a vehicle body frame via a bracket. In a supported motorcycle exhaust system, the exhaust system includes a dynamic balancer on the exhaust pipe between the lower part of the radiator and the lower end of the front opening of the cowling in front of the engine, and immediately before the dynamic balancer. An exhaust device for a motorcycle, wherein a located exhaust pipe is bent so that a running wind hitting the dynamic balancer is not obstructed. 2. The exhaust device for a motorcycle according to claim 1, wherein the dynamic balancer is provided on the exhaust pipe via a bracket, and the bracket forms a traveling air passage between the exhaust pipe and the exhaust pipe.