JPH09166011A - Noise reducing device of exhaust pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reduction of contact surface pressure, and exhibit vibration damping action for a long period by forming a projection part on the outer surface of an exhaust pipe according to the installing position of a damper, and fixing to the exhaust pipe the both end parts of the damper positioned on the both sides while striding the projection part, and fastening at least one of bottom part. SOLUTION: An annular projection part 5 is formed on a part for installing the damper 3 of an exhaust pipe 1. The outer surface of the exhaust pipe 1 is covered with the damper 3 while striding the projection part 5, both end parts of the damper 3 is tensed, and looseness is not generated in the longitudinal direction of the exhaust pipe 1. A fixing band 7 abuts on the both end parts of the damper 3, and the damper 3 is fixed to the exhaust pipe 1 together with the fixing band 7. A fastening band is used while striding the projection part 5, bottom parts 5a, 5b of both sides are fastened, and a clearance formed between the damper 3 and the exhaust pipe 1 is eliminated. It is thus possible to hold contact surface pressure generated between the damper 3 and the exhaust pipe 1 for a long period, and reduce dispersion of noise reducing effect caused by an individual difference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe noise reduction device for reducing radiated sound caused by vibration transmitted from an internal combustion engine to an exhaust pipe.

[0002]

2. Description of the Related Art Conventionally, in a vehicle equipped with an internal combustion engine such as an automobile or a motorcycle, when vibration of the internal combustion engine is transmitted to an exhaust pipe, radiated sound is generated from the exhaust pipe, which causes noise. Therefore, the present inventor has found that FIG. 14 and FIG.
As shown in FIG. 2, a spring 2 is fixed to the surface of the exhaust pipe 1, and a damper 3 formed by weaving a metal wire such as a steel wire so as to cover the spring 2 is brought into contact with the exhaust pipe 1.
I have found a way to reduce the sound emitted from.

This is because the elastic force of the spring 2 interposed between the exhaust pipe 1 and the damper 3 is used to apply tension to the damper 3 so that the damper 3 is brought into close contact with the exhaust pipe 1 so that the exhaust gas from the internal combustion engine is exhausted. The vibration transmitted to the pipe 1 is transmitted to the damper 3 in contact with the exhaust pipe 1. Then, by vibrating the metal wire 4 constituting the damper 3 woven and woven as shown in FIGS. 16 and 17,
The vibration is damped by causing friction between the woven metal wires 4 and between the metal wires 4 and the surface of the exhaust pipe 1 and converting the vibration energy into heat energy.

[0004]

By the way, if a spring is installed inside the damper as described above, the damper can be brought into close contact with the exhaust pipe with a certain force due to the elastic force of the spring. During the installation work, the spring, which is a protrusion, is easily caught on the damper, and since the damper is inserted while compressing the spring, there is a problem that it takes time to insert the damper into the exhaust pipe during the manufacturing process. It was Further, there is a problem that the contact surface pressure generated between the damper and the exhaust pipe decreases due to the deterioration of the spring with time, and the noise reducing effect decreases.

In view of the above problems, the present invention makes it possible to easily mount a damper formed by weaving metal wires, and to strengthen the damper and the exhaust pipe with a simple structure without using a spring. Provided is a noise reduction device for an exhaust pipe, which can be brought into close contact with each other and has no fear of a reduction in contact surface pressure between the damper and the exhaust pipe due to deterioration over time, and which can exhibit the vibration damping action of the damper for a long period of time The purpose is to do.

[0006]

In order to achieve the above object, an exhaust pipe noise reduction apparatus according to the present invention has a damper formed by weaving a metal wire in close contact with the outer surface of the exhaust pipe of an internal combustion engine. A noise reducing device for an exhaust pipe comprising a convex portion formed on the outer surface of the exhaust pipe corresponding to the mounting position of the damper, and both end portions of the damper located on both sides across the convex portion are connected to the exhaust pipe. And a hem portion of at least one of the protrusions is fastened with a tightening band.

Another exhaust pipe noise reduction device according to the present invention is an exhaust pipe noise reduction device in which a damper formed by weaving a metal wire is closely attached to the outer surface of the exhaust pipe of an internal combustion engine. So, while forming a recess on the outer surface of the exhaust pipe corresponding to the mounting position of this damper, both ends of the damper located on both sides across this recess are fixed to the exhaust pipe,
The recess is tightened with a tightening band.

As the damper, a wire blade or the like in which metal wires such as steel wires are woven and woven in a mesh shape is suitable, and by weaving, metal wires which are vertically stacked are rubbed against each other. When fixing both ends of the damper to the exhaust pipe, the damper is fixed in a state of being stretched in the longitudinal direction of the exhaust pipe. In that case, in addition to the method of directly fixing the metal wire at the longitudinal end of the damper to the exhaust pipe, annular brackets are attached to both ends of the damper and the damper is fixed to the exhaust pipe through the brackets. Alternatively, it may be fixed by using a fixing band. Although welding is most suitable as a means for fixing the damper, other methods such as brazing or riveting may be used.
The position of the protrusion or the recess is preferably at the center of the damper with respect to the longitudinal direction of the exhaust pipe, but is not particularly limited.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of an exhaust pipe noise reduction device according to the present invention will be described with reference to the drawings. First, as shown in FIG. 1, in the exhaust pipe 1, an annular convex portion 5 is formed in a portion where the damper 3 is attached. In the present embodiment, when forming the convex portion 5, a method of applying a water pressure P from the inside to plastically deform the exhaust pipe 1 by using a mold 6 as shown in FIG. 2 is used. Exhaust pipe 1
The outer surface of the above may be subjected to build-up welding, or another component such as a protruding ring may be welded. In addition, this convex portion 5
Does not have to be a perfect annular shape, but the effect is significantly reduced if it is formed only in a small part, so it is preferable to form it in more than half of the circumference of the exhaust pipe 1.

On the other hand, the damper 3 attached to the exhaust pipe 1 is the same as that shown in FIGS. 16 and 17, and a plurality of metal wires (steel wires) bundled in a band shape are used as warp threads and weft threads, respectively. A tubular wire braid woven into a cloth by braiding these at right angles to each other. The inner diameter of the damper 3 is set to be substantially equal to the outer diameter of the exhaust pipe 1.

When attaching the damper 3 to the exhaust pipe 1, first, the exhaust pipe 1 is inserted into the damper 3. At that time, since the inner diameter of the damper 3 is smaller than the outer diameter of the convex portion 5, the damper 3 is caught by the convex portion 5, but by compressing the damper 3 in the longitudinal direction of the exhaust pipe 1, the stitches are displaced so that the inner diameter expands. There is no problem because it does. Then, as shown in FIG. 3, the exhaust pipe 1 provided with the convex portions 5 is covered with a damper 3 on the outer surface of the exhaust pipe 1, and both ends of the damper 3 are pulled to extend the length of the exhaust pipe 1. Make sure there is no slack in the direction. In this state, the fixing band 7 shown in FIG. 4 is brought into contact with both ends of the damper 3, and the damper 3 is fixed to the exhaust pipe 1 by welding together with the fixing band 7. The fixing band 7 is formed by press-molding a steel plate having a thickness of about 0.8 mm. Spot welding is performed as shown by an arrow S in FIG. 5 and an end portion of the exhaust pipe 1 is shown by an arrow L. It is fixed by wire welding so as to go around the outer surface.

Thereafter, by using the tightening band 8 as shown in FIG. 6 so as to straddle the convex portion 5, the hem portions 5a on both sides of the convex portion 5,
Tighten 5b to eliminate the gap C between the damper 3 and the exhaust pipe 1 shown in FIG. The tightening band 8 is formed by bending both ends of the main body portion 8a to form flange portions 8b, and forming a slit 9 around the outer surface of the exhaust pipe in the central portion, so that the gap C is eliminated. This flange part 8b
Is fixed by spot welding.

Since the damper 3 is pressed in the direction indicated by the arrow A in the figure by the above-mentioned tightening band 8, as a result, the tension toward the convex portion 5 is applied to the damper 3 itself by the arrow B as shown in FIG. Occurs in the direction indicated by. This allows
The stitches are displaced so that the inner diameter of the damper 3 is narrowed, and a force for tightening the exhaust pipe 1 from the surroundings acts, so that the damper 3 comes into close contact with the exhaust pipe 1.

As a method for fixing the tightening band 8, in addition to the above spot welding, as shown in FIG. 9, a means such as fastening using a bolt 10 and a nut 11 or fixing by caulking is used. May be. By the above-described mounting method, the noise reduction device 12 for the exhaust pipe 1 shown in FIG. 10 is finally completed.

Next, another embodiment of the present invention is shown in FIG. This is common to the above-described embodiment in that the convex portion 5 is formed on the exhaust pipe 1, the damper 3 is covered so as to straddle the convex portion 5, and both ends thereof are welded using the fixing band 7. However, the mounting position of the damper 3 with respect to the position of the convex portion 5 is different, and one end of the damper 3 is fixed to one hem portion 5a of the convex portion 5 and the other hem portion 5b is fixed by the tightening band 8. By tightening, the tension shown by the arrow B in the figure is produced.

Yet another embodiment of the present invention is shown in FIGS. In this, a recess 13 is formed in the middle of the exhaust pipe 1, the outer surface of the exhaust pipe 1 including the recess 13 is covered with the above-mentioned damper 3, and the fixing bands 7 are provided on both ends of the damper 3.
Is provided and welded to the exhaust pipe 1, and the recess 13 of the exhaust pipe 1 is tightened from above the damper 3 by the tightening band 8.

[0017]

The exhaust pipe noise reduction device according to the present invention comprises:
A noise reduction device for an exhaust pipe, comprising a damper formed by weaving a metal wire in close contact with the outer surface of the exhaust pipe of an internal combustion engine, wherein a protrusion is formed on the outer surface of the exhaust pipe corresponding to the mounting position of the damper. Along with forming the, both ends of the damper located on both sides across this convex portion is fixed to the exhaust pipe, and at least one hem portion of the convex portion is tightened with a tightening band. The following effects can be achieved.

The damper in the portion corresponding to the convex portion of the exhaust pipe bulges outward, and before tightening the tightening band, there is a gap between the hem and the damper. After tightening the band, the gap disappears or decreases significantly, so that tension is generated in the damper in the longitudinal direction of the exhaust pipe, and the inner diameter of the damper is reduced accordingly. Can be improved.

Another exhaust pipe noise reduction device according to the present invention is an exhaust pipe noise reduction device in which a damper formed by weaving a metal wire is closely attached to the outer surface of the exhaust pipe of an internal combustion engine. So, while forming a recess on the outer surface of the exhaust pipe corresponding to the mounting position of this damper, both ends of the damper located on both sides across this recess are fixed to the exhaust pipe,
Since the recess is tightened with the tightening band, the following effects can be obtained.

Since the damper in the portion corresponding to the recess of the exhaust pipe is substantially horizontal with the outer surface of the exhaust pipe, there is a gap between the recess and the damper before tightening the tightening band. However, after tightening this tightening band, the gap disappears or decreases significantly, so that tension is generated in the damper in the longitudinal direction of the exhaust pipe, and the inner diameter of the damper is reduced accordingly, which reduces the exhaust gas. The adhesion to the pipe can be improved.

Therefore, in either case, the damper can be securely brought into close contact with the exhaust pipe with a very simple structure, and the noise caused by the vibration transmitted from the internal combustion engine can be reduced. Further, since a spring is not used as in the past, it is possible to easily attach a damper formed by weaving a metal wire, and moreover, the contact surface pressure generated between the damper and the exhaust pipe is kept for a long time. Can be held over.

Furthermore, by appropriately adjusting the tightening force of the tightening band in addition to the height of the convex portion or the depth of the concave portion, it is possible to adjust the degree of close contact between the damper and the exhaust pipe. It is possible to reduce variations in the noise reduction effect due to.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an exhaust pipe according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a means for forming a convex portion on the exhaust pipe of FIG.

FIG. 3 is a schematic cross-sectional view showing a state where a damper is attached to the exhaust pipe of FIG.

FIG. 4 is a perspective view of a fixing band for mounting the damper of FIG.

5 is a cross-sectional view of essential parts showing a state in which the fixing band of FIG. 4 is welded.

6 is a perspective view of a tightening band for tightening the damper of FIG. 3. FIG.

7 is a schematic cross-sectional view showing a state before tightening of the tightening band in FIG.

8 is a schematic cross-sectional view showing a state after tightening of the tightening band of FIG.

FIG. 9 is a schematic side view showing a fixing method for each tightening band for tightening the damper of FIG.

FIG. 10 is a perspective view of an exhaust pipe noise reduction device according to an embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view of an exhaust pipe noise reduction device according to another embodiment of the present invention.

FIG. 12 is a perspective view of a main part of an exhaust pipe according to still another embodiment of the present invention.

13 is a schematic cross-sectional view of a noise reduction device applied to the exhaust pipe shown in FIG.

FIG. 14 is a schematic perspective view showing a state before attachment of a conventional noise reduction device for an exhaust pipe.

15 is a cross-sectional view of essential parts of the exhaust pipe noise reduction device shown in FIG.

FIG. 16 is a partial front view of a damper used in the exhaust pipe noise reduction device.

FIG. 17 is an enlarged perspective view of the damper shown in FIG.

[Explanation of symbols]

 1 Exhaust Pipe 3 Damper 4 Metal Wire 5 Convex 5a Bottom 5b Bottom 8 Tightening Band 12 Noise Reduction Device 13 Recess

Claims (2)

[Claims] 1. A noise reduction device for an exhaust pipe, wherein a damper formed by weaving a metal wire is brought into close contact with the outer surface of the exhaust pipe of an internal combustion engine, and the exhaust pipe noise reduction device corresponds to the mounting position of the damper. While forming a convex portion on the outer surface, fixing both ends of the damper located on both sides across this convex portion to the exhaust pipe, tightening at least one skirt of the convex portion with a tightening band. A characteristic exhaust pipe noise reduction device. 2. A noise reduction device for an exhaust pipe, wherein a damper formed by weaving a metal wire is brought into close contact with an outer surface of the exhaust pipe of an internal combustion engine, and the exhaust pipe corresponds to a mounting position of the damper. An exhaust pipe noise reduction device characterized in that a recess is formed on the outer surface, both ends of dampers located on both sides of the recess are fixed to the exhaust pipe, and the recess is fastened with a tightening band. .