JPH0742530A - Abnormal sound preventing mechanism for muffler - Google Patents

Abstract

PURPOSE:To suppress the shift of a sound absorbing member even if the volume of a sound absorbing member contracts because of thermal deterioration. CONSTITUTION:On the outer periphery of an exhaust gas communication pipe 1, a cylindrical sound absorbing member 2 is arranged, and further, on the outer periphery of the sound absorbing member 2, a cylindrical cover body 3a is arranged. On the outer peripheral surface of the connection part between an exhaust gas communication pipe 1 and exhaust tubes 4 and 5, one edge part of each cap 3b, 3c is coaxially fitted. Each cap 3b, 3c closes the opened port edge part of the exhaust gas communication pipe 1, and the other edge part is fitted on the outer periphery of the opened port edge part of the gas communication pipe 1, and a cover 3 is constituted, together with the cover body 3a. Between the cap 3b on the left side and the edge part in the axial direction of the sound absorbing member 2, a coil spring 6 is interposed in a compressed state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer for absorbing sound energy of exhaust gas flow by a sound absorbing material, and more particularly,
The present invention relates to a noise suppression mechanism for a silencer that prevents abnormal noise generated by a sound absorbing material in the silencer.

[0002]

2. Description of the Related Art Conventionally, as a silencer using a sound absorbing material, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-38315, many silencers are formed on the outer wall of an exhaust gas flow pipe. A cylindrical cover is coaxially arranged so as to cover the sound passage small hole portion, and a sound absorbing material such as glass wool 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 as to prevent the noise from being generated due to the movement of the sound absorbing material due to resonance with the exhaust gas flow. As described in Japanese Patent Application Laid-Open No. 58-38315, the sound absorbing material is housed in the cover through the bag body, and the sound absorbing material in the bag is in a dense state, and the mouth of the bag body is closed. The other end is fixed to the exhaust gas flow pipe with a metal band or the like to prevent the sound absorbing material from moving, thereby preventing the abnormal noise.

[0004]

However, in the noise suppressing mechanism of the muffler described above, the sound absorbing material is housed in the cover or the bag in a dense state in the initial state at the time of assembly. However, during repeated contact with a high-temperature and high-pressure exhaust gas flow, the sound absorbing material has a volume contracted from the initial state due to heat deterioration, etc., and a gap is formed between the cover and the exhaust gas flow pipe. Transition. Then, the sound absorbing material resonates with the exhaust gas flow and dances, and noise is generated due to collision with the cover and the outer wall of the exhaust gas flow pipe.

The present invention has been made in view of the above problems, and an object thereof is to suppress the movement of the sound absorbing material even if the volume of the sound absorbing material is reduced due to heat deterioration or the like.

[0006]

In order to achieve the above object, the noise suppressor of the muffler of the present invention has a main body on the outer periphery of an exhaust gas flow pipe having a large number of sound passage holes in its wall. Is a cylindrical body that is coaxial with the exhaust gas flow pipe and has both ends thereof closed by closing members, and a sound absorbing material is filled between the exhaust gas flow pipe and the cover. The silencer 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 portion of the cover in the axial direction and the sound absorbing material.

Alternatively, the main body is made of a cylindrical body coaxial with the exhaust gas flow pipe and both ends thereof are closed by closing members around the outer periphery of the exhaust gas flow pipe having a large number of sound passage small holes in the wall. In a silencer in which a cover made up of is disposed and a sound absorbing material is filled between the exhaust gas flow pipe and the cover,
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 constantly pressed by the spring member,
Even if the volume of the sound absorbing material shrinks due to heat deterioration or the like, the sound absorbing material is compressed and maintained in a dense state by the above-mentioned pressing, and at the same time, the sound absorbing material is pressed against the end portion of the cover, thereby the cover and the spring member A pressure is applied between them, and movement of the cover in the axial direction and the radial direction is suppressed.

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

[0010]

Embodiments 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 a cylindrical glass fiber or the like is arranged on the outer periphery of an exhaust gas flow pipe 1 having a large number of sound passage small holes 1a formed in an outer wall. Further, a cylindrical cover body 3a is provided on the outer periphery of the sound absorbing material 2.

The sound absorbing material 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. There is. In addition, at both end openings 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 the exhaust tubes 4 and 5, respectively.
One ends of b and 3c are coaxially fitted to connect the both 1, 4 and 5, respectively. Each of the caps 3b and 3c closes the opening end of the cover body 3a, and the other end is fitted and fixed to the outer circumference of the opening end of the cover body 3a to form a closing member. So,
The cover 3 is configured with the cover body 3a.

A coil spring 6 constituting a spring member is interposed in a compressed state between the cap 3b on the left side in FIG. 1 and the axial end of the sound absorbing material 2. The coil spring 6 is arranged 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, and thereby takes a reaction force to the left cap 3b. The sound absorbing material 2 is constantly urged toward the right cap 3c.

As a result, the sound absorbing material 2 is constantly urged by a predetermined pressing force, and is in a crimped 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 → the exhaust gas flow pipe 1 → the right exhaust tube 5. Then, a part of the exhaust gas flow flowing in the exhaust gas flow pipe 1 passes through the sound absorbing material 2 through the sound passage small holes 1a, and the sound absorbing material 2 converts the sound energy of the exhaust gas flow into heat energy. Is muted.

At this time, the sound absorbing material 2 contracts more than the initial state due to thermal deterioration during repeated contact with the high temperature and high pressure exhaust gas flow, but due to the stable elastic force of the coil spring 6, the sound absorbing material 2 is always on the right side. Since the cap 3c is pressed toward the cap 3c, the state in which the coil spring 6 and the right cap 3c are crimped at a predetermined density is always maintained.

Therefore, even if the sound absorbing material 2 resonates with the exhaust gas flow, the movement of the sound absorbing material 2 is suppressed, and the sound absorbing material 2 does not collide with the exhaust gas flow pipe 1 or the cover 3, but abnormal noise 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 also formed between the sound absorbing material 2 and the exhaust gas flow pipe 1, but in the dense state as described above. Since it is pressed in the axial direction and is in a crimped state, it is also prevented from moving in the radial direction.

Further, as shown in FIG. 2, the silencer having the above-mentioned abnormal sound preventing mechanism is assembled by, for example, welding one end of the coil spring 6 into the left cap 3b in advance. After being fixed, as shown in FIG. 3, the left side exhaust pipe 4 is attached to the left side exhaust tube 4 and the left end portion of the exhaust gas flow pipe 1 is connected by the conventional assembling method. Sound absorbing material 2 on the outer circumference of the pipe 1.
After further disposing the cover main 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 advance in the left cap 3b in order to simplify the assembly, but it need not be fixed separately. Further, in the above embodiment, the coil spring 6 is provided only at the left end portion, but the coil spring 6 may be similarly provided at the right end portion.

Further, in the above embodiment, the end portion of the coil spring 6 is fixed to the cap 3b to exert a reaction force on the cap 3b, but as shown in FIG. 4, one end portion of the exhaust gas flow pipe 1 is used. One end of the coil spring 6 is fixedly attached to the outer peripheral surface of the sound absorbing member 2 by applying a reaction force to the exhaust gas flow pipe 1.
You may make it urge | bias axially the end part of. Further, as shown by the chain double-dashed line in FIG. 2, a ring-shaped pressing plate 7 is coaxially attached to the open end side of the coil spring 6 so that the end surface of the sound absorbing material 2 can be pressed as uniformly as possible. You may comprise a spring member with this and the pressing plate 7.

Further, 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 and coil springs 8 may be arranged along the outer circumference of the exhaust gas flow pipe 1, and the pressing plate 7 may be attached to the free end side to form a spring member. Further, in the above embodiment, one end portion of the sound absorbing material 2 is urged by the spring member, but as shown in FIG. 6, the sound absorbing material 2 is divided in the middle and the coil spring 6 and the pressing plate 7 are provided therebetween. By interposing a spring member coaxially, each of the divided sound absorbing members 2a, 2b is pressed in the axial direction, thereby,
The sound absorbing members 2a and 2b may be pressed against the end portions of the covers 3.

In the above embodiment, the sound absorbing material 2 formed in a cylindrical shape has been described, but 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 body 3a are described as separate bodies, but they may be integrally formed.

[0022]

As described above, in the noise reduction mechanism of the muffler of the present invention, even if the sound absorbing material contracts due to heat deterioration or the like, the sound absorbing material is always in the dense state and in the axial direction. Since it is pressed, movement is suppressed, and the generation of abnormal noise is prevented.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an abnormal sound preventing mechanism of a muffler according to an embodiment of the present invention.

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

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

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

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

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

[Explanation of symbols]

 1 Exhaust Gas Flow Pipe 1a Sound Small Hole 2 Sound Absorbing Material 3 Cover 3a Cover Main Body 3b, 3c Cap 6 Coil Spring 7 Pressing Plate

Claims (2)

[Claims] 1. An outer periphery of an exhaust gas flow pipe having a large number of sound passage small holes in a wall portion, a main body made of a tubular body coaxial with the exhaust gas flow pipe, and both ends thereof are closed by a closing member. In a muffler in which a cover made up of the above is disposed, and a sound absorbing material is filled between the exhaust gas flow pipe and the cover, in the axial direction of the cover between the end of the cover in the axial direction and the sound absorbing material. A noise canceling mechanism for a muffler, comprising a spring member capable of urging a sound absorbing material. 2. An outer periphery of an exhaust gas flow pipe having a large number of sound passage small holes in a wall portion, a main body of which is a tubular body coaxial with the exhaust gas flow pipe, and both ends of which are closed by closing members. In a muffler in which a cover made up of the above is disposed and a sound absorbing material is filled between the exhaust gas flow pipe and the cover, the sound absorbing material in the axial direction of the cover is absorbed in the sound absorbing material in the middle of the cover in the axial direction. An abnormal noise preventing mechanism for a muffler, characterized in that a spring member capable of urging is installed.