JPS6143938Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a muffler for an internal combustion engine mounted on a motorcycle or the like.

In the case of an internal combustion engine mounted on a motorcycle, the muffler is a long cylinder-shaped muffler and is installed along the lower side of the vehicle body, so there are restrictions on the shape of the muffler.
In addition, the muffler's outer cylinder gradually expands the exhaust gas, and the outer diameter of the muffler gradually increases toward the end, which is effective in muffling noise. Inside the muffler outer cylinder, a partition wall is provided in the middle, and the front and rear silencing chambers are communicated with each other by a thick pipe that penetrates the partition wall.
The front and rear ends of the buttful pipe come into contact with the muffler outer cylinder and the tail pipe, so there are space constraints. The buttful pipe may be installed at an angle from the axis, but in this case, the burring of the buttful pipe through hole in the partition plate must be slanted, which is difficult to do with one press punching and takes time to manufacture. In addition, there is a type in which the rear part of the full pipe is bent so as to escape the tail pipe, but this has the disadvantage that it is difficult to achieve precision in the bent part, making it time-consuming and costly to manufacture.

This invention has been improved in view of the above points so that it can be manufactured at a low cost.Hereinafter, an embodiment of the invention shown in the drawings will be described.

The muffler outer cylinder 1 is formed into a shape in which the outer diameter gradually becomes wider at the end, and the inlet pipe 2 is inserted and welded to the front end, and the closing plate 4 to which the tail pipe 3 is welded is welded to the tail end. Ru. In the middle, an intermediate partition plate 6 is welded and fixed with the buttful pipe 5 passed through and welded thereto. The inlet pipe 2, the tail pipe 3, and the full pipe 5 each need a predetermined length and thickness in order to muffle sound in a predetermined frequency range. Therefore, in the present invention, the front end portion of the full pipe 5 is moved inward and processed into a flat shape 7, and the rear end portion is moved outside and processed into a flat shape 8. Oblate 7
and 8 can be achieved by passing the full pipe 5 through the intermediate partition plate 6 and welding it, and then crushing it according to the jig.

Therefore, by making the front and rear ends flat 7 and 8, the full pipe 5 can avoid hitting the muffler outer cylinder 1 and the tail pipe 3,
Since it can be welded to the middle fence partition plate 6 parallel to the axis, workability is good and manufacturing is easy. and,
The thick pipe 5 does not need to be made thinner, and the sound deadening effect can be increased.

As explained above, this invention uses a muffler outer cylinder whose outer diameter gradually becomes wider at the end. In addition, the flattened flattened pipe with its rear end moved outward is passed through and fixed in the front and rear direction, so that the front and rear ends of the rounded pipe are prevented from hitting the muffler outer cylinder and the tail pipe. This makes it possible to install the buttful pipe parallel to the axis of the muffler outer cylinder, making it easy to align during production and burring the holes in the intermediate partition plate through which the buttfull pipe is passed, reducing the time and effort required for production. Therefore, costs can be reduced. Moreover, thick pipes can be used, and the sound damping effect is also great. For this reason, there is no need to divide the full pipe into multiple thin pipes.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Fig. 1 is a longitudinal sectional view, Fig. 2 is a transverse sectional view taken along the line A-A in Fig. 1, and Fig. 3 is a longitudinal sectional view.
The figure is a cross-sectional view taken along the line BB in FIG. 1. 1...Muffler outer cylinder, 5...Bullet pipe, 6
...Intermediate partition plate, 7...Flat, 8...Flat.

Claims (1)

[Scope of utility model registration request] In those using a muffler outer cylinder whose outer diameter gradually becomes wider at the end, an intermediate partition plate fixed to the middle part of the muffler outer cylinder has a front end part moved inward to make it flat, and a rear end part A muffler for an internal combustion engine characterized by a flattened outward-facing pipe that penetrates and is fixed in the front-rear direction.