JPH0318653Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle exhaust pipe that reduces vehicle exhaust discharge noise.

[Prior art]

According to vehicle-related laws and regulations, in automobiles, a tail pipe 2 attached to a muffler 1 is used as shown in Figure 7.
The opening 3 is directed toward the right side of the vehicle, that is, toward the rear of the center of the road, or toward the right side for exhaust air. As shown in FIG. 8, this opening 3 is formed perpendicularly to the axis L of the tail pipe 2, and the exhaust gas flow direction indicated by the arrow and the exhaust sound emission direction indicated by the chain arrow are both along the axis L. Therefore, there is a problem in that the noise on the right side of the vehicle becomes abnormally loud, especially during acceleration.

In order to solve this problem, the applicant
-19786 provides an exhaust pipe sound insulation device.

Although this device itself is effective, it is complex and expensive.

[Purpose of invention]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle exhaust pipe with a simple structure that reduces vehicle exhaust noise.

[Principle of invention]

The present invention was obtained as a result of various studies.When the rear end opening of the exhaust pipe is cut obliquely to the axis to form a cut surface, the exhaust gas flow is discharged in a direction slightly along the cut surface rather than in the axial direction. This is based on the principle that the discharge sound is radiated in a direction perpendicular to the cut surface.

[Structure of the idea]

In the vehicle exhaust pipe according to the present invention, a sound absorbing material is provided in the emission direction of exhaust discharge sound of the exhaust pipe, which has an open end in which the direction of exhaust gas flow and the direction of emission of exhaust discharge sound are different from each other.

[Function and effect of the idea]

Therefore, the exhaust discharge sound directed in a direction different from the exhaust gas flow is absorbed by the sound absorbing material, and as a result, the exhaust discharge sound of the vehicle can be reduced with a simple structure.

[Preferred embodiment]

When implementing the present invention, it is preferable to cut the rear end opening of the exhaust pipe diagonally with respect to the exhaust pipe axis, and to direct the cut surface formed by the cut toward the inside of the vehicle. It is preferable to form the tube at an angle of 30° to 70° toward the front of the vehicle with respect to a base line that is perpendicular to the tube axis and faces toward the inside of the vehicle.

When implementing the present invention, it is preferable to cut the rear end opening of the exhaust pipe at right angles to the exhaust pipe axis, and to provide a flow control plate projecting downstream that slightly widens toward the center of the road.

In implementing the present invention, the sound absorbing material is preferably attached to the exhaust pipe or the frame via a bracket that is concentric with the exhaust pipe and has an arcuate cross section.

When implementing the present invention, it is preferable to use glass wool, sintered alloy, or the like as the sound absorbing material.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In Figures 1 to 3, the tail pipe 1
A cut surface 11 cut obliquely with respect to the axis L of the tail pipe 10 is formed at the rear end opening of the tail pipe 10.

The cut angle θ of the cut face 11 is formed at 30° to 70° on the vehicle front side F with respect to a base line B that is orthogonal to the axis L of the tail pipe 10 and directed toward the vehicle center line side A. If the cut angle θ is less than 30°, the cutting effect will be small, and if it is more than 70°, the tailpipe 1
Since 0 would be too long, it is formed at an angle of 30° to 70° as described above, but 60° is most preferable.

The tail pipe 10 has a base 1 inside the vehicle.
2a is welded to the tail pipe 10, and the end 12b
A bracket 12 is fixedly installed, which is expanded concentrically with the tail pipe 10, has an arcuate cross section, faces the cut surface 11, and has a tip protruding from the base line B. Note that this bracket may be integrally formed by enlarging a part of the tail pipe. Furthermore, this bracket may be fixed to the frame without being welded to the tail pipe 10. A sound absorbing material 13 made of glass wool, sintered metal, or the like is attached to the inner periphery of the bracket 12.

Next, the effect will be explained.

Due to the principle mentioned above, the exhaust gas flow is as shown by the arrow.
The discharge sound is emitted in a direction along the cut surface 11, that is, to the right side, slightly from the axis L, and the discharge sound is radiated in a direction perpendicular to the cut surface 11, as indicated by the chain arrow, and is directed inside the vehicle, that is, toward the sound absorbing material 13. 13, the sound is absorbed. As a result, the noise on the right side is reduced.

4 to 6 show another embodiment of the present invention, in which the rear end opening of the tail pipe 14 is cut at right angles to the axis L, and a flow control plate 15 slightly widened on the right side is cut downstream. This is an example in which it is provided protrudingly from the side, and the rest is configured similarly to the previous embodiment. In this embodiment, the cut surface 16 shown by the dashed line is similar to the principle described above.
There is an effect similar to that obtained by forming , and therefore, there is an effect similar to that of the previous embodiment.

〔summary〕

As explained above, according to the present invention, the exhaust discharge sound directed in a direction different from the exhaust gas flow is absorbed by the sound absorbing material, and as a result, the exhaust discharge sound on the center side of the road of the vehicle can be reduced with a simple structure. can.

[Brief explanation of the drawing]

1 to 3 and 4 to 6 show main parts of the first and second embodiments of the present invention,
Figures 1 and 4 are external perspective views, Figures 2 and 5 are top views, Figures 3 and 6 are front views,
Figure 7 is a top view showing the exhaust pipe of a conventional truck;
FIG. 8 is an enlarged view of the main part of FIG. 7. 10, 14... Tail pipe, 11... Cut surface, 12... Bracket, 13... Sound absorbing material, 15
...Flow control board.

Claims (1)

[Scope of utility model registration request] An exhaust pipe for a vehicle, characterized in that a sound absorbing material is provided in the direction of emission of exhaust discharge sound of the exhaust pipe, which has an open end in which the direction of exhaust gas flow and the direction of emission of exhaust discharge sound are different.