JP2976754B2 - Abnormal noise prevention mechanism of silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for absorbing sound energy of an exhaust gas flow by means of a sound absorbing material.
The present invention relates to a noise suppressor for a muffler for preventing abnormal noise generated by a sound absorbing material in the muffler.

[0002]

2. Description of the Related Art Conventionally, as a muffler utilizing a sound absorbing material, for example, as described in Japanese Patent Application Laid-Open No. 58-38315, a number of mufflers formed on the outer wall of an exhaust gas flow pipe are known. A cylindrical cover is provided coaxially so as to cover the small sound passage portion, and a sound absorbing material made of glass wool or the like is housed between the outer wall of the exhaust gas flow pipe and the cover.

Conventionally, the sound absorbing material is filled with the sound absorbing material in accordance with the volume between the outer wall and the cover so that the sound absorbing material does not move due to resonance with the exhaust gas flow or the like to generate abnormal noise. As described in JP-A-58-38315, the sound absorbing material is housed in the cover via a bag, and the sound absorbing material in the bag is closed and the mouth of the bag is closed. The other end is fixed to the exhaust gas flow pipe with a metal band or the like to suppress the movement of the sound absorbing material, thereby preventing the occurrence of the abnormal noise.

[0004]

However, in the above-described noise reduction mechanism of the silencer, in the initial state at the beginning of the assembly, the sound absorbing material is housed in the cover or the bag in a dense state. However, during repeated contact with the high-temperature and high-pressure exhaust gas flow, the sound absorbing material shrinks in volume from the initial state due to thermal deterioration or the like, and enters a state in which there is a gap between the cover and the exhaust gas flow pipe. Transition. Then, the sound absorbing material resonates with the exhaust gas flow and dances, and generates abnormal noise due to collision with the cover or the outer wall of the exhaust gas flow pipe.

The present invention has been made in view of the above problems, and has as its object to suppress the movement of the sound absorbing material even if the volume of the sound absorbing material is reduced due to thermal degradation or the like.

[0006]

In order to achieve the above-mentioned object, a noise suppressing mechanism for a silencer according to the present invention comprises a main body mounted on an outer periphery of an exhaust gas flow pipe having a plurality of small sound holes in a wall portion. Is provided with a cover formed of a cylindrical body coaxial with the exhaust gas flow pipe and having both ends closed by closing members, and filled with a sound absorbing material between the exhaust gas flow pipe and the cover. The muffler is characterized in that a spring member capable of urging the sound absorbing material in the axial direction of the cover is interposed between the end of the cover in the axial direction and the sound absorbing material.

[0007] Alternatively, the main body is formed of a cylindrical body coaxial with the exhaust gas flow pipe, and both ends of the exhaust gas flow pipe are closed with closing members on the outer periphery of the exhaust gas flow pipe having a plurality of small sound holes in the wall. In the silencer that is provided with a cover made of, and filled with a sound absorbing material between the exhaust gas flow pipe and the cover,
It is characterized in that a spring member capable of urging the sound absorbing material in the axial direction of the cover is interposed in the sound absorbing material in the middle of the cover in the axial direction.

[0008]

[Function] Since the sound absorbing material is always pressed by the spring member,
Even if the volume of the sound-absorbing material shrinks due to thermal deterioration or the like, the above-described pressing causes the sound-absorbing material to be compressed and maintained in a dense state, and at the same time to be pressed against the end of the cover so that the cover and the spring member And the cover is prevented from moving in the axial and radial directions.

Thus, the movement of the sound absorbing material due to resonance with the exhaust gas flow or the like is suppressed, and the generation of abnormal noise is suppressed.

[0010]

An embodiment of the present invention will be described with reference to the drawings.
First, the configuration will be described. As shown in FIG. 1, a sound absorbing material 2 made of glass fiber or the like having a cylindrical shape is arranged on the outer periphery of an exhaust gas distribution pipe 1 having a large number of small sound transmission holes 1a formed on an outer wall. Further, a cylindrical cover main body 3a is provided on the outer periphery of the sound absorbing material 2.

The sound absorbing member 2 has an inner peripheral surface having a diameter capable of engaging with the outer wall of the exhaust gas flow pipe 1 and an outer peripheral surface having a diameter capable of engaging with the inner peripheral wall of the cover body 3a. I have. In addition, at both ends of the exhaust gas flow pipe 1,
The exhaust tubes 4 and 5 are respectively connected.

A cap 3 is provided on the outer peripheral surface of the connecting portion between the exhaust gas flow pipe 1 and each of the exhaust tubes 4 and 5.
One ends of b and 3c are coaxially fitted to connect the two 1, 4 and 5, respectively. Each of the caps 3b and 3c closes the opening end of the cover main body 3a, and the other end is fitted and fixed to the outer periphery of the opening end of the cover main body 3a to form a closing member. With
The cover 3 is configured together with the cover body 3a.

A coil spring 6 constituting a spring member is interposed between the left cap 3b in FIG. 1 and the axial end of the sound absorbing material 2 in a compressed state. The coil spring 6 is disposed coaxially with the exhaust gas flow pipe 1 in the cover 3 so as to go around the outer circumference of the exhaust gas flow pipe 1, thereby taking a reaction force on the left cap 3 b, The sound absorbing material 2 is constantly biased toward the right cap 3c.

As a result, the sound absorbing material 2 is constantly urged with a predetermined pressing force, and is brought into a press-fit state with a predetermined density between the coil spring 6 and the right cap 3c. In this state, high-temperature and high-pressure exhaust gas flows from the left exhaust tube 4 to the exhaust gas flow pipe 1 to the right exhaust tube 5. A part of the exhaust gas flow flowing in the exhaust gas flow pipe 1 passes through the sound absorbing material 2 through the small sound passage 1a, and the sound absorbing material 2 converts the sound energy of the exhaust gas flow into thermal energy. Is muted.

At this time, while repeating the contact with the high-temperature and high-pressure exhaust gas flow, the sound absorbing material 2 contracts more than the initial state due to thermal deterioration. Since the coil spring 6 is pressed toward the cap 3c, a state in which the coil spring 6 is crimped at a predetermined density is always maintained between the coil spring 6 and the right cap 3c.

For this reason, even if the sound absorbing material 2 resonates with the exhaust gas flow, the movement of the sound absorbing material 2 is suppressed, so that the sound absorbing material 2 does not collide with the exhaust gas flow pipe 1 or the cover 3 and the abnormal sound is generated. Is prevented. Here, the sound absorbing material 2 is reduced in the radial direction of the exhaust gas flow pipe 1 due to thermal deterioration, and a gap is formed between the sound absorbing material 2 and the exhaust gas flow pipe 1. Since it is pressed in the axial direction and is in a pressed state, the movement in the radial direction is also suppressed.

In addition, as shown in FIG. 2, for example, as shown in FIG. 2, assembling of the silencer provided with the abnormal noise prevention mechanism having the above-described structure is performed by previously welding one end of the coil spring 6 into the left cap 3b. After being fixed, as shown in FIG. 3, the left cap 3b is attached to the left exhaust tube 4 and the left end of the exhaust gas flow pipe 1 is connected by the conventional assembling method. Sound absorbing material 2 on the outer circumference of tube 1
After further arranging the cover body 3a on the outer periphery thereof, the right cap 3c and the right exhaust tube 5 are assembled while pressing the sound absorbing material 2 to the left.

In the above embodiment, the coil spring 6 is fixed in the cap 3b on the left side in advance to simplify the assembly. However, it is not necessary to fix the coil spring 6 separately. Further, in the above embodiment, the coil spring 6 is provided only at the left end, but the coil spring 6 may be provided at the right end in the same manner.

In the above embodiment, the end of the coil spring 6 is fixed to the cap 3b to exert a reaction force on the cap 3b. However, as shown in FIG. One end of the coil spring 6 is fixed to the outer peripheral surface, and a reaction force is applied to the exhaust gas flow pipe 1 so that the sound absorbing material 2
May be biased in the axial direction. As shown by a two-dot chain line in FIG. 2, a ring-shaped pressing plate 7 is coaxially attached to the open end of the coil spring 6 so that the end face of the sound absorbing material 2 can be pressed as uniformly as possible. And the pressing plate 7 may constitute a spring member.

In the above embodiment, the exhaust gas flow pipe 1
Although one coil spring 6 is arranged coaxially with
As shown in FIG. 5, a plurality of leaf springs or coil springs 8 may be arranged along the outer circumference of the exhaust gas flow pipe 1, and a pressing plate 7 may be attached to the free end side to form a spring member. Further, in the above embodiment, one end of the sound absorbing material 2 is urged by the spring member. However, as shown in FIG. 6, the sound absorbing material 2 is divided on the way and includes the coil spring 6 and the pressing plate 7 therebetween. A spring member is coaxially interposed to press each of the divided sound absorbing members 2a and 2b in the axial direction.
Each of the sound absorbing members 2 a and 2 b may be pressed against the end of each cover 3.

In the above embodiment, the sound absorbing material 2 formed into a cylindrical shape is described. However, as in the conventional case, a short sound absorbing material is stored in a bag, and the bag is placed in the cover 3. May be filled. Further, in the above embodiment, the caps 3b and 3c as the closing members and the cover main body 3a are described as separate bodies, but they may be integrally formed.

[0022]

As described above, in the silence prevention mechanism of the silencer of the present invention, even if the sound absorbing material contracts due to thermal deterioration or the like, the sound absorbing material is always kept in a dense state and in the axial direction. Since it is pressed, the movement is suppressed, and there is an effect that generation of abnormal noise is prevented.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an abnormal noise prevention mechanism of a silencer according to an embodiment of the present invention.

FIG. 2 is a side view showing attachment of the coil spring according to the embodiment of the present invention.

FIG. 3 is an exploded perspective view showing an abnormal noise prevention mechanism of the muffler according to the embodiment of the present invention.

FIG. 4 is a side view showing attachment of a coil spring according to a second embodiment of the present invention.

FIG. 5 is a side view showing attachment of a coil spring according to a third embodiment of the present invention.

FIG. 6 is a side view showing attachment of a coil spring according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust gas flow pipe 1a Small sound transmission hole 2 Sound absorbing material 3 Cover 3a Cover body 3b, 3c Cap 6 Coil spring 7 Press plate

Claims (2)

(57) [Claims] 1. An exhaust gas flow pipe having a plurality of small sound holes in a wall thereof, the main body of which is formed of a cylindrical body coaxial with the exhaust gas flow pipe, and both ends of which are respectively closed by closing members. A muffler in which a sound absorbing material is filled between the exhaust gas flow pipe and the cover, wherein the cover has an axial direction between the end of the cover and the sound absorbing material. An abnormal noise prevention mechanism for a silencer, wherein a spring member capable of urging a sound absorbing material is interposed. 2. A body comprising a cylindrical body coaxial with the exhaust gas flow pipe on the outer periphery of the exhaust gas flow pipe having a large number of small sound holes in the wall, and both ends of which are respectively closed by closing members. A muffler in which a sound absorbing material is filled between the exhaust gas flow pipe and the cover, wherein the sound absorbing material in the axial direction of the cover is provided in the sound absorbing material in the middle of the cover in the axial direction. A noise prevention mechanism for a silencer, comprising a spring member capable of urging the sound.