JPS61138814A - Exhaust pipe for motorcycle - Google Patents

Abstract

PURPOSE:To aim at the promotion of lightweightiness as well as to prevent an exhaust pipe from discoloring, by forming the exhaust pipe connecting from an engine exhaust port so a muffler, into one-layer pipe of stainless steel. CONSTITUTION:An exhaust pipe 4 connecting from an engine exhaust port to a muffler 5 is formed into one-layer pipe. With this formation, it can be made lighter in weight, and although it is of one-layer pipe in structure, a heat transfer rate is little and, what is more, since it is made up of stainless steel being strong against oxidation, heating due to direct heat transmission out of the exhaust port and surface discoloration due to heat of exhaust gas are in no case entailed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an exhaust pipe of an exhaust system provided in a motorcycle.

[Prior art]

In the exhaust system of a motorcycle, the exhaust pipe that connects the engine exhaust hole and the muffler is placed in a visually conspicuous position, so its surface is chrome-plated and has a beautiful metal finish. It is made to have a glossy finish. However, the plating changes color and loses its beautiful metallic luster due to direct heat transfer from the connection with the exhaust hole and heating by high-temperature exhaust gas passing through the exhaust pipe. Additionally, when the surface is polished to remove this discolored portion, there is a problem in that the plating peels off.

Conventional exhaust pipes have a double pipe structure in order to eliminate the cause of discoloration caused by the exhaust gas, and measures such as injecting heat insulating material into the space between the double pipes have been taken. However, even with such a double-pipe structure, it is not possible to prevent discoloration near the exhaust port connection due to direct heat transfer from the exhaust port, and furthermore, the double-pipe structure causes an increase in weight. [Object of the Invention] An object of the present invention is to provide an exhaust pipe for a motorcycle that can prevent surface discoloration in the vicinity of the exhaust port connection portion without causing an increase in weight. The purpose is to provide tubes.

[Structure of the invention]

The present invention, which achieves the above object, is characterized in that the exhaust pipe connecting from the exhaust hole of the engine to the muffler is formed into a single pipe, and the exhaust pipe is made of stainless steel.

〔Example〕

The present invention will be explained below with reference to embodiments shown in the drawings.

In the motorcycle shown in FIG. 3, 1 is a body frame;
2 is a two-cylinder engine mounted on this body frame 1, and 3 is an exhaust system. The exhaust system 3 includes an exhaust pipe 4 connected to an exhaust hole of the engine 2, and a muffler 5 connected to the rear end of the exhaust pipe 4 and disposed below the engine 2. 13 is a front wheel, and 14 is a rear wheel.

As shown in FIGS. 1 and 2, the exhaust pipe 4 of the exhaust device 3 is formed of only a single pipe and is made of stainless steel, and its surface is not particularly plated. Further, the muffler 5 of the exhaust device 3 is composed of a first expansion chamber 6 and a second expansion chamber 7, and sound deadening materials 8 and 9 made of glass wool are adhered to the inner walls of each of them. The two exhaust pipes 4°4 are collected into a communication pipe 10 and communicate with the first expansion chamber 6, and the first expansion chamber 6 is connected to the second expansion chamber 7 by a communication pipe 11, and the second expansion chamber 7 is communicated with the outside air through a communication pipe 12.

The first expansion chamber 6 forms an outer shell that combines a box-shaped portion located below the engine 2 and a convex portion that largely protrudes upward at the rear of the engine 2, and has an extremely large capacity. It has become. On the other hand, the second expansion chamber 7 is disposed on the side of the vehicle body, and its capacity is relatively small because the capacity of the first expansion chamber 6 is -larger.

Therefore, the rear end of the second expansion chamber 7 is located near the front end of the rear end 14, and is significantly closer to the front than the rear end position of the muffler of the conventional exhaust system. With such a configuration closer to the front, the MM of the silencer 5 is concentrated at the center of gravity of the vehicle,
This is advantageous in improving vehicle handling stability.

According to the above-mentioned exhaust system, since the exhaust pipe 4 has a single-pipe structure, it can be made lighter than the conventional double-pipe structure exhaust pipe.

In addition, even with this double-tube structure, the exhaust gas is made of stainless steel, which has a thermal conductivity less than 1/4 of that of ordinary steel and is extremely resistant to oxidation. Not only heating by direct heat transfer from the holes, but also heating by high-temperature exhaust gas will not cause surface discoloration, and the entire exhaust pipe 4 from the exhaust hole connection to the muffler will always maintain a beautiful metallic luster. can do. Furthermore, even if slight discoloration occurs, the original metallic luster can be easily restored by polishing the surface.

〔Effect of the invention〕

As mentioned above, in the present invention, the exhaust pipe connecting from the exhaust hole of the engine to the muffler is formed into a single pipe, so it can be made lightweight. is made of stainless steel that has low thermal conductivity and is resistant to oxidation, so there is no heating due to direct heat transfer from the exhaust hole or surface discoloration due to heating of the exhaust gas, and there is no possibility of surface discoloration due to heat transfer from the exhaust hole to the silencer. The entire exhaust pipe can always be kept with a beautiful metallic luster. Also, even if discoloration occurs, by polishing the surface,
Can be easily restored to its original metallic luster.

[Brief explanation of the drawing]

FIG. 1 is a side view partially showing an exhaust system having an exhaust pipe according to an embodiment of the present invention, FIG. 2 is a plan view partially showing the same exhaust system in cross section, and FIG. 3 is a side view showing the same exhaust system partially in section. FIG. 2 is a side view of a motorcycle provided with a. 2... Engine, 3... Exhaust system, 4... Exhaust pipe, 5... Silencer.

Claims (1)

[Claims] An exhaust pipe for a motorcycle, characterized in that an exhaust pipe connecting an engine exhaust hole to a silencer is formed into a single pipe, and the exhaust pipe is made of stainless steel.