JPS5993918A - Exhaust gas silencer device of motorcycle - Google Patents

Abstract

PURPOSE:To improve weight balance without forcing a motor-bicycle into an unreasonable external design, by a method wherein an exhaust pipe, coupled to the exhaust port of a single cylinder engine for a motorcycle, is caused to branch in front of a rear wheel, and silencers are disposed on both sides of a car body. CONSTITUTION:A single cylinder engine 3 is placed on a down tube 2 of a motorcycle, the front end of an exhaust pipe 6 is coupled to an exhaust port 3a thereof, and the front end is bent in the lateral direction of a car body after it is bent downward. In this case, the exhaust pipe 6 is enlarged and bent at the outer diameter part thereof to form an expansion chamber, and the side parts of the car body are extended backward. The exhaust pipe 6 branches into two branch pipes 6a and 6b in position where it reaches the front of a rear wheel 5, the branch pipe 6a extends along the same side of the car body as it is, but the branch pipe 6b extends across the car body at the front side of a rear frame 8 to the opposite side. Silencers 8a and 8b are connected to the two branch pipes 6a and 6b respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust silencing device for a crab wheeled vehicle.

Among the noise generated by the engine, high-frequency component noise can be attenuated by using sound-absorbing materials such as glass stripes in the exhaust pipe, or by installing many small-sized expansion chambers in the muffler. However, noise with low frequency components below I KHz cannot be attenuated unless the capacity of the muffler is increased. However, in the case of motorcycles where space is limited, increasing the size of the silencer itself while maintaining the conventional configuration would result in an overlapping appearance, and there is a limit to increasing the size from a design standpoint.

In particular, in the case of a motorcycle equipped with a single-cylinder engine, one exhaust pipe is disposed only on one side of the vehicle body, so as the muffler becomes larger, the entire motorcycle becomes unbalanced, which is undesirable.

In view of the above-mentioned problems, it is an object of the present invention to effectively attenuate low frequency component noise generated by an engine without causing unnaturalness to the external design of a motorcycle equipped with an i-cylinder engine. The purpose of the present invention is to provide an exhaust silencer for motorcycles that can perform the following functions.

The exhaust silencing device of the present invention, which achieves the above object, is provided in a motorcycle equipped with an S-cylinder engine. The plugged exhaust pipe is extended rearward along one side of the vehicle body, and branched in front of the wheels.
The feature is that each branch pipe is connected to a silencer placed on both sides of the vehicle body.

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

In the figure, 1 is the main frame, 2 is the down tube, and 3
is a two-stroke single-cylinder engine fixed above the down tube 2, 4 is a front wheel, and 5 is a rear wheel.

The front end of an exhaust pipe 6 is connected to the exhaust port 3a of the engine 3, and the exhaust pipe 6 bends downward and then in the lateral direction of the vehicle body, forming an expansion chamber 9 whose outer diameter is enlarged and bent. The sides of the car body are further extended towards the rear. This exhaust pipe 6 is branched into two branch pipes 6a and 6b at a position reaching the front of the rear wheel 5. One of these branch pipes 6
The branch pipe a extends rearward on the same side of the vehicle body as t', while the other branch pipe 6b extends from the front side of the rear frame 8 across the vehicle body to the opposite side surface. The branch pipe 6a branched in this way.

6b, silencers 8a each placed on both sides of the vehicle body.
, 8b are connected. Expansion chamber 9 with increased diameter
The inside of the H8a has a sound absorbing material pasted on its inner surface, similar to known ones, and a sound deadening H8a.

Is the inside of 8b the same as the publicly known one? J! The structure is divided into several small expansion chambers.

According to the above-mentioned exhaust silencer, the exhaust pipe is branched and there are two silencers connected to the rear, placed on both sides of the vehicle body, so the capacity of the silencer increases accordingly, and the capacity of one silencer is insufficient. It becomes possible to sufficiently attenuate the noise of low frequency components. Moreover, instead of unnecessarily increasing the size of one silencer, two
Since they are arranged on both sides so as to be discrete and balanced with respect to the vehicle body, there is no unnatural appearance to the overall external design of the motorcycle equipped with a single-cylinder engine.

In addition, in the case of a motorcycle equipped with a two-stroke engine as in the above embodiment, an expansion chamber 9 is provided in the exhaust pipe, and the reflected wave from the expansion chamber 9 toward the exhaust port causes the exhaust port to This prevents the intake air from blowing through and maintains engine performance. Therefore, in order to prevent the function of the expansion chamber 9 from being adversely affected, it is desirable that the branch portion of the exhaust pipe 6 be located downstream of the expansion chamber 9.

In the above embodiment, the case of a motorcycle equipped with a 2-cycle 11-cylinder engine was described, but the present invention is applicable to a 4-stroke motorcycle]! It can also be applied to motorcycles equipped with 菟B engines.

As described above, the exhaust silencer of the present invention is provided in a motorcycle equipped with an 11-kiran engine, in which the exhaust pipe connected to the exhaust port of the engine is extended rearward along one side of the vehicle body. The pipes are branched in front of the rear wheels, and silencers placed on both sides of the vehicle are connected to each branch pipe.
Since the noise reduction is set to $11, the capacity of the silencer increases as a whole, and it is possible to attenuate the low-frequency power noise generated by the engine. Moreover, since the two silencers are placed separately on both sides of the vehicle, the size of each silencer is not unnecessarily large, and because it is balanced left and right, it is suitable for the exterior design of motorcycles equipped with I-cylinder engines. It does not cause any unnaturalness.

[Brief explanation of drawings]

FIG. 1 is a side view of a motorcycle equipped with the exhaust silencer of the present invention, No. 21i! 1 is a plan view of the same mouth crab wheel wheel. 3... Engine, 5... Rear wheel, 6... Exhaust pipe, 6a, 6b... Branch pipe, 8a, 8b...
·Silencer. Agent: Patent Attorney Makoto Ogawa − Patent Attorney: Teru Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] In a motorcycle equipped with a single-cylinder engine, an exhaust pipe connected to the exhaust port of the engine is extended rearward along one side of the vehicle body and branched in front of the rear wheel, and each branch pipe is connected to both sides of the vehicle body. A motorcycle exhaust silencer that connects a silencer placed in the