JPS6231618Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust system used in internal combustion engines of motorcycles, etc.

BACKGROUND ART In internal combustion engines such as motorcycles, a subchamber communicating with an exhaust passage is provided in a part of an exhaust pipe to increase exhaust efficiency and increase engine output, particularly at medium and low speeds.

On the other hand, the exhaust pipe is installed above and to the rear of the engine. In this case, the exhaust pipe is suspended downward from the engine exhaust port, bent into a front U-shape, and further The upper part is bent backwards, and it has a complex shape that is evenly bent and extends further backwards.

The present invention was developed with a focus on the above-mentioned subchamber and exhaust pipe, and its purpose is to provide a subchamber in the upstream part of the exhaust pipe that communicates with the exhaust passage and aims to improve output, and to connect the closed end of the subchamber to the exhaust pipe. To provide an exhaust device which is fixed to other parts of the pipe and is constructed between the bent parts to reinforce the bent part of the exhaust pipe as a cross member and to provide vibration isolation of the subchamber.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a side view of a motorcycle.
A front fork 4 supporting a front wheel 5 is pivotably supported via a head tube 3 at the front end of the frame 2, and an engine 6 is mounted at the lower front of the frame 2.
Further, a fuel tank 7 is mounted on the upper part, and a rear fork 8 is pivotally extended rearward from the lower rear end of the frame 2, and the rear fork supports a rear wheel 9. The upstream end of an exhaust pipe 10 is connected to the front part of the engine 6, and the exhaust port of the engine and the exhaust pipe are connected in communication.

The details of the exhaust pipe 10 are as shown in FIGS. 2 to 5, and the upstream end 10a of the exhaust pipe 10 is provided with a flange portion 11 for attachment to an engine exhaust port. exhaust pipe 1
The most upstream part 10b of 0 slightly protrudes forward, from which the intermediate upstream part 10c is bent and hangs downward, and is bent outward from the lower part of the intermediate upstream part into a front U-shape as shown in FIG. In the embodiment, the intermediate base portion 10e is erected upward from the portion 10d so as to be slanted forward so as to face the upstream portions 10b and 10c apart from each other. Bend the upper part of the intermediate base 10e backward 1
0f, extends rearward as an intermediate portion 10g, and extends a tail pipe 13 from the rear end of the intermediate portion 10g.
A muffler 14 is connected to the rear end of this. The above-mentioned exhaust pipe 10 has an upstream part facing outward on one side of the down tube 2a of the frame 2, an intermediate base located outside of the upstream part, and an intermediate part 10 upstream of the tail pipe 13.
g is disposed so as to pass below the side of the tank 7 and above the engine.

A mounting hole 15 with an upright periphery 15a is provided on the periphery of the upstream end 10a of the exhaust pipe 10 facing the intermediate base 10e, and the upstream end 16a of the tube-shaped subchamber 16 is fit and welded into the mounting hole 15. do. The downstream end 16b of the subchamber 16 is closed by crushing, etc., and the downstream end 16b is welded and fixed to the opposing outer surface 10h of the intermediate base 10e of the exhaust pipe 10. As a result, the subchamber 16 is horizontally suspended between the upper portions of the front portions A of the exhaust pipes bent into a U-shape from the front. In the drawing, reference numeral 17 denotes a cover provided to cover the outer periphery of the downstream end of the subchamber 16, and is fixed to the downstream end with screws 18. Also in the drawing 1
2 indicates a reaction unit.

Next, to explain its functions and effects in detail, the subchamber 16 suppresses the backflow to the engine of pressure waves caused by exhaust pulsation caused by engine operation in the exhaust passage, improving engine output in medium and low speed ranges. be able to. By the way, as described above, the exhaust pipe 10 is bent in a U-shape from the front, and the upper part is bent backward and extended further rearward, so that the exhaust pipe 10 has a complicated bent shape. Since the tube-shaped subchamber 16 is installed as a cross member between these U-shaped bent parts, the strength is improved, and the rigidity of the front part A is increased even when vibrations are applied during engine operation, which is extremely advantageous in terms of vibration resistance. Also, the mounting strength is greatly improved. Even though the subchamber 16 is tube-shaped, both ends are fixed, which improves its own strength and is advantageous in terms of vibration isolation. The above can be contemplated with a simple structure in which the subchamber is bridged over the bent portion.

The present invention has many advantages as described above.

In the embodiment, the present invention was used in an exhaust system for a motorcycle, but the present invention can be applied to any desired object.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a schematic side view of a motorcycle, Fig. 2 is a side view of an exhaust pipe, Fig. 3 is a sectional view of a subtube communication connection part, and Fig. 4 is a schematic side view of a motorcycle. Partially cutaway view of subtube connection,
FIG. 5 is a side view of the subchamber closed end attachment portion. In the drawing, 10 is an exhaust pipe, 16 is a subchamber,
16a is an upstream end, and 16b is a closed downstream end.

Claims (1)

[Scope of utility model registration request] In an exhaust system in which a part of an exhaust pipe is provided with a subchamber whose one end communicates with an exhaust passage and whose other end is closed, the exhaust pipe is provided with a bent part, and one end of the subchamber is communicated with the upstream part of the bent part. and the other closed end is fixed to the downstream side of the upstream portion of the bent portion of the exhaust pipe.