JPS5924807Y2 - Double exhaust pipe of internal combustion engine - Google Patents

Description

[Detailed explanation of the idea] This invention relates to an improvement of a dual exhaust pipe for an internal combustion engine.

When the exhaust gas temperature of an internal combustion engine is high, the exhaust pipe is sometimes made into a double pipe consisting of an inner pipe and an outer pipe to prevent discoloration of the plated surface of the outer pipe.

In that case, if only one end of the outer tube and inner tube are fixed by welding,
Although it can cope with the elongation of the inner and outer tubes due to temperature differences, stress may be applied to the welded parts and cracks may occur.

Also, if you weld one end of the inner and outer tubes and make a widened part in the inner tube at the other end and press fit it into the outer tube, there will be no stress on the welded part, but the inner tube will not be able to stretch freely and will stretch. Sometimes it makes strange noises and the contact surface wears out, making it uncomfortable.

This invention has been improved in view of these points, and an embodiment of the invention shown in the drawings will be described below.

The proximal end of the inner tube 2 is expanded and fitted to the proximal end of the outer tube 1, and welded.

Several holes 3 are provided at the tip of the inner tube 2.

Then, a steel ball 4 of a size that will not fall out is inserted into the hole 3.

The outer end of the steel ball 4 is brought into contact with the inner surface of the outer tube 1.

Note that 5 is a cap connected to the exhaust port of the engine.

The effect will be explained.

Hot exhaust gas passes inside the inner tube 2.

Due to this thermal influence, the inner tube 2 expands more than the outer tube 1 and stretches in the longitudinal direction.

Since the steel ball 4 fitted into the hole 3 is in point contact with the inner surface of the outer tube 1, it can be easily expanded in the axial direction.

In addition, the inner tube 2 is supported by the welded portion at the proximal end of the outer tube 1 and the steel ball 4, so that no undue force is applied to the welded portion.

As explained above, this idea involves inserting the inner tube into the outer tube with a gap, fixing the proximal end of the inner tube to the proximal end of the outer tube, and making several holes at the tip of the inner tube. A steel ball large enough to not fall out is inserted, and the outer end of the steel ball is in contact with the inner surface of the outer tube, so the inner tube is supported at both ends and no excessive force is applied to the weld, causing cracks. There is no such thing.

Further, the tip of the inner tube is in point contact with the inner surface of the outer tube via the steel ball, and can easily expand and contract due to heat.

In addition, since steel balls can be produced by hand at low cost, manufacturing costs can also be reduced.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, with Figure 1 being a longitudinal sectional view and Figure 2 being a longitudinal sectional view.
The figure is an enlarged cross-sectional view taken along the line A-A in FIG. 1... Outer pipe, 2... Inner pipe, 3...
...hole, 4...steel ball.

Claims (1)

[Scope of utility model registration request] Insert the inner tube into the outer tube with a gap, fix the proximal end of the inner tube to the proximal end of the outer tube, make several holes at the tip of the inner tube, and insert steel balls large enough to prevent them from falling out. A double exhaust pipe for an internal combustion engine, characterized in that the outer end of the steel ball is brought into contact with the inner surface of an outer pipe.