JP2007291884A - Muffler for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a muffler for a vehicle capable of improving durability of sound absorbing material without deteriorating muffling performance, and improving durability of the muffler for the vehicle. <P>SOLUTION: This muffler is provided with a pipe body 3 in which exhaust gas circulates, a plurality of opening projection part 5 formed on an outer circumference of the pipe body 3 with projecting inward and including a small hole 6 opening toward a downstream side of the exhaust gas, and the sound absorbing material 4 provided on an outer circumference of the pipe body 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a muffler for a vehicle.

2. Description of the Related Art Conventionally, a vehicle silencer is provided in the middle of an exhaust pipe for combustion gas of an engine, and a silencing process for attenuating a noise component caused by a combustion gas explosion contained in the exhaust is performed.
Various types of mufflers for vehicles are known, and various structures are adopted according to various conditions such as the size of the engine, but it attenuates high-frequency noise components. As a structure for this, a plurality of small holes provided in the silencer main body and opened in the axial direction of the tubular body on the outer periphery of the tubular body through which the exhaust gas flows, or outward on the outer periphery of the tubular body A technique of a vehicle silencer in which a plurality of projecting opening projections are formed and a sound absorbing material is provided on the outer periphery of the tubular body is known (see Patent Documents 1 to 4).
Japanese Utility Model Publication No.59-154816 JP 2006-9679 A JP 2003-161135 A JP-A-8-1253

However, in a conventional vehicle silencer, high-temperature and high-speed exhaust gas that circulates through the pipe directly collides with the sound-absorbing material through small holes or opening projections of the pipe, and the temperature of the sound-absorbing material increases. There was a problem that durability deteriorated due to deterioration and damage.
In addition, since it is practically difficult to repair and replace only the sound absorbing material, when the sound absorbing material is deteriorated or damaged, the muffler for the vehicle is replaced, resulting in a high repair cost.

Further, if the sound absorbing material is made of a material having high heat resistance, there is a problem that the cost of the material is increased.
The purpose of this type of vehicle silencer is to attenuate the pressure impact associated with the flow of exhaust gas through the tube with the sound absorbing material, and the effect is achieved by the sound absorbing material receiving the exhaust gas directly. It cannot be obtained.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to improve the durability of the sound absorbing material without impairing the sound deadening performance, and thus to improve the durability of the vehicle silencer. It is providing the silencer for vehicles which can be performed.

  According to the first aspect of the present invention, a pipe body provided in the silencer main body, through which exhaust gas flows, is formed to project inwardly on the outer periphery of the pipe body, and is downstream of the exhaust gas. It is characterized by comprising a plurality of opening protrusions having small holes that open toward and toward the outer periphery of the tubular body.

  According to the first aspect of the present invention, a pipe body provided in the silencer main body, through which exhaust gas flows, and formed to project inwardly on the outer periphery of the pipe body, and the exhaust gas The sound absorbing material is provided on the outer periphery of the tubular body, and the durability of the sound absorbing material can be improved without impairing the sound deadening performance. The durability of the silencer can be improved.

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

Example 1 will be described below.
In the first embodiment, a case where the vehicle silencer is applied to a sound absorbing sub-muffler will be described.
1 is a half cross-sectional view showing a vehicle silencer according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line S2-S2 of FIG. 1, and FIG. 3 is an enlarged view of the vicinity of an opening protrusion of the first embodiment. FIG. 4 is a diagram for explaining the method of manufacturing a vehicle silencer.

First, the overall configuration will be described.
As shown in FIGS. 1 to 3, the vehicle silencer 1 according to the first embodiment includes a cylindrical silencer body 2, a cylindrical tube 3, and a cylindrical sound absorbing material 4.

The silencer main body 2 is made of metal and is formed in a substantially cylindrical shape, and inclined tapered portions 2a having a reduced diameter are formed at both ends thereof.
A reduced diameter portion 2b continuously reduced to the outer diameter of the tube body 3 is continuously fixed to the tube body 3 by welding 2c on the front and rear sides of the entire circumference of the taper portion 2a.

The tubular body 3 has the above-mentioned welding 2c in a state of passing through the center hole 4a of the sound absorbing material 4 filled in the space between the reduced diameter portion 2b of the silencer body 2 and the inside of the silencer body 2 and the outside of the tubular body 3. In addition to being fixed to the silencer main body 2, a plurality of opening projections 5 projecting in a substantially semi-cannonball shape toward the inside are formed in the circumferential direction at predetermined intervals (four in the first embodiment). In addition, a small hole 6 having a substantially semicircular shape (see FIG. 2) opened to the exhaust gas downstream side is formed in each opening protrusion 5.
In the first embodiment, the opening protrusions 5 adjacent to each other in the axial direction of the tubular body 3 are offset from each other. However, the present invention is not limited to this, and the number and positions of the opening protrusions 5 can be set as appropriate.

The sound absorbing material 4 absorbs the pressure shock (sound wave) of the exhaust gas as the vibration of the fiber or cancels the vibration. For example, after forming a fiber material made of glass wool into a cylindrical shape, an adhesive or the like Solidified using is used.
Or after forming the one taper part 2a and inserting the pipe | tube body 3, before filling the other taper part 2a, what was filled with the non-shaped glass wool may be employ | adopted.

  Further, as shown in FIG. 3, the center hole 4 a of the sound absorbing material 4 is provided in contact with the outer periphery of the tube body 3, and the tube body 3 through the recessed space O of the opening protrusion 5 and the small hole 6. It is in a state where it communicates with the inside.

Next, the operation will be described.
When manufacturing the vehicle silencer 1 configured as described above, first, the tube 3 is formed.
As a method of forming the tube 3, after forming a slit to be a small hole 6 in a metal plate material to be manufactured, the slit is protruded by a press working device to form an opening protrusion 5. Is wound around the outer periphery of the cylindrical mandrel so that the opening protrusion 5 is on the inner peripheral side, and the both end edges are welded to obtain the desired tubular body 3.
A recess groove that is recessed toward the center of the mandrel is formed on the outer periphery of the mandrel over the entire length in the axial direction at a portion corresponding to the opening protrusion 5, thereby It is possible to prevent the opening protrusion 5 from being crushed by inserting the opening protrusion 5 into the recess groove when wound around the outer periphery, and at the same time, the mandrel can be pulled out in the axial direction and removed from the tube body 3.

  Alternatively, after a metal plate material to be manufactured is wound around the outer periphery of a cylindrical mandrel and both end edges are welded 2c to form a cylindrical body, a portion corresponding to the opening protrusion 5 on the outer periphery of the cylindrical body is stubbed. A desired tubular body 3 is obtained by forming the opening protrusion 5 by cutting and raising inward with a processing apparatus. In addition, you may use the appropriate method and apparatus other than the above for the manufacturing method of the tubular body 3.

Next, as shown in FIGS. 4A and 4B, the tubular body 3 is inserted into the central hole 4a of the cylindrical sound absorbing material 4 and disposed at a predetermined position.
At this time, since the opening protrusion 5 is not caught by the sound absorbing material 4, it can be smoothly inserted into the center hole 4 a without damaging the sound absorbing material 4.
Next, as shown in FIG. 4 (c), after inserting the tubular body 3 and the sound absorbing material 4 into the metal cylindrical body 7 which becomes the silencer main body 2, a pair of upper and lower jigs around the central portion thereof. Fix by sandwiching with the tool 8.
Next, as shown in FIG. 4 (d), the plurality of rotating rollers 9 are rotated around the axis of the cylindrical body 7 while rotating around the rotation axis (direction of arrow A) at both ends of the cylindrical body 7. The muffler body 2 is formed by forming the taper portion 2a and the reduced diameter portion 2b by so-called spinning that repeatedly moves along the outer shape (arrow B direction) of the tapered portion 2a and the reduced diameter portion 2b to be manufactured gradually. .
Finally, a desired vehicle silencer 1 is obtained by welding 2c the reduced diameter portion 2b to the outer periphery of the tubular body 3 at both ends of the silencer body 2.

  In the vehicle silencer 1 configured as described above, one end side of the tube 3 is connected to a connection exhaust pipe on the engine side (not shown), and the other end side is connected to a connection exhaust pipe on the main muffler side (not shown). The

As shown in FIG. 1, high-temperature and high-speed exhaust gas (illustrated by a wavy arrow) flows from the exhaust gas upstream side of the tube body 3 and flows to the exhaust gas downstream side.
At this time, as shown in FIG. 3, a part of the exhaust gas flowing along the inner peripheral surface of the tube body 3 (illustrated by a wavy arrow X) moves to the exhaust gas downstream side along the opening protrusion 5. On the other hand, the pressure shock (shown by the one-dot chain line arrow Y) accompanying the circulation of the exhaust gas enters from the small hole 6 of the opening protrusion 5 and is attenuated by the sound absorbing material 4, whereby noise, mainly high-frequency noise can be silenced. .

  Therefore, when the small hole 6 of the opening protrusion 5 is opened toward the exhaust gas downstream side, the high-temperature and high-speed exhaust gas passing through the tube 3 passes through the small hole 6 of the opening protrusion 5 and the sound absorbing material 4. Thus, the temperature of the sound absorbing material 4 can be prevented from being increased, and the durability of the sound absorbing material 4 and thus the durability of the vehicle silencer 1 can be improved.

  In addition, when the sound absorbing material is provided in a state of facing from the outside of the small hole, the sound absorbing material directly receives the exhaust gas by forming the opening protruding portion so as to protrude outward from the outer periphery of the tube body. However, in this embodiment, since the sound absorbing material 4 is provided on the outer periphery of the tubular body 3 in a solid state in a cylindrical shape in advance, the recessed space O can be reliably formed between the opening protrusion 5 and the sound absorbing material 4, Thereby, there is no possibility that the sound absorbing material 4 is provided in a state of facing the small hole 6, and the sound absorbing material 4 can be prevented from receiving exhaust gas directly.

Next, the effect will be described.
As described above, in the vehicle silencer 1 according to the first embodiment, the silencer body 2 is provided in the silencer body 2, and the pipe body 3 through which the exhaust gas circulates is disposed inside the outer periphery of the pipe body 3. And a plurality of opening protrusions 5 having small holes 6 that are open toward the downstream side of the exhaust gas and the sound absorbing material 4 provided on the outer periphery of the tube body 3, so that the sound deadening performance is not impaired. The durability of the sound absorbing material 4 can be improved, and as a result, the durability of the vehicle silencer 1 can be improved.

Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, in the first embodiment, the case where the vehicle silencer is applied to the sub-muffler has been described.

  The sound absorbing material may be formed in a mat shape and wound around the outer periphery of the tube, or may be configured by joining a plurality of divided bodies.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a half sectional view showing a vehicle silencer according to a first embodiment of the present invention. It is sectional drawing in the S2-S2 line | wire of FIG. It is a figure explaining the enlarged view of the opening projection part vicinity of a present Example 1, and an effect | action. It is a figure explaining the manufacturing method of the silencer for vehicles.

Explanation of symbols

O Recessed space 1 Vehicle silencer 2 Silencer body 2a Tapered portion 2b Reduced diameter portion 2c Welding 3 Tube 4 Sound absorbing material 4a Center hole 5 Opening projection 6 Small hole 7 Tubular body 8 Jig 9 Rotating roller

Claims (1)

A pipe body provided in the silencer body and through which exhaust gas flows;
A plurality of opening projections formed on the outer periphery of the tubular body inward and having small holes opened toward the downstream side of the exhaust gas;
A muffler for a vehicle comprising a sound absorbing material provided on an outer periphery of the tubular body.

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