JP2006022749A - Slide support structure of tube in exhaust system of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slide support structure slidably supporting a tube such as an exhaust pipe in an exhaust system of an engine of an automobile or the like, favorably support a tube without large frictional noise and abnormal sound in the case of slidably supporting the tube such as inner and outer pipes in a hollow double exhaust pipe through a space made of a metal wire. <P>SOLUTION: In this slide support structure of the tube in the exhaust system of an engine, the tube 31 is slidably supported through the spacer 6 made of a metal wire. The slide load when the tube 31 relatively slides in the axial direction to the spacer 6 due to thermal expansion is 60 kgf or less at ordinary temperature. Preferably the density of the spacer 6 made of metal wire is ranging from 2.2 ×10<SP>3</SP>kg/m<SP>3</SP>to 2.85 × 10<SP>3</SP>kg/m<SP>3</SP>. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a slide support structure that supports a pipe body such as an exhaust pipe so as to be slidable in an exhaust system of an engine such as an automobile.

  2. Description of the Related Art Conventionally, in an exhaust system of an engine such as an automobile, a pipe body such as an exhaust pipe is slidably supported. Specifically, for example, as described in Patent Documents 1 to 3 below, exhaust manifolds and exhaust pipes are formed in an inner and outer double, a predetermined interval is secured so that the inner and outer pipes do not interfere with each other, and the inner and outer pipes For the purpose of absorbing a shift due to a difference in thermal expansion or the like, the inner and outer tubes are supported so as to be relatively movable (slidable) by interposing a metal wire spacer between the inner and outer tubes. Alternatively, it has been proposed that one or both of the inner and outer pipes are slidably supported with respect to a fixing member such as a vehicle body via a spacer similar to the above.

  However, as described above, the pipe body such as the inner and outer pipes that are slidably supported through the spacer made of the metal wire material is loose when the contact pressure between the pipe body and the spacer is weak, and the vehicle body vibration or the like. In contrast, if the contact pressure between the tube and the spacer is too strong, smooth expansion and contraction of the tube due to exhaust heat etc. may be hindered and a large sliding noise may be generated. is there. In particular, when the pipe is thermally expanded due to exhaust heat when the engine is driven, and the engine is stopped and the temperature rapidly decreases and contracts, the pipe and the spacer are strongly rubbed to generate a large friction noise or abnormal noise. There were problems such as. In addition, the actual situation is that it is impossible to determine at what level the contact pressure between the tube body and the spacer generates a large frictional noise or abnormal noise.

JP-A-10-266835 JP-A-9-280046 JP-A-8-246870

  The present invention has been proposed in view of the above-described conventional problems. When a tubular body such as the above-described inner and outer pipes is slidably supported via a metal wire spacer, a large frictional noise or abnormal noise is generated. An object of the present invention is to provide a slide support structure for a tubular body in an exhaust system of an engine that can be favorably supported without causing any problems.

  In order to achieve the above object, the present inventor has intensively studied, and as a result, the tube body and the spacer are relatively moved in a state in which the tube body such as the inner and outer pipes is slidably supported by the metal wire spacer. When the slide is moved, a sliding sound is generated. The sliding sound is almost proportional to the slide load, that is, the initial load required to start the relative slide movement increases. As a result, it has been found through experiments that the frictional noise and noise that are uncomfortable in terms of sound pressure are generated when the slide load exceeds a predetermined value, and the present invention has been completed.

That is, the tubular slide support structure in the exhaust system of the engine according to the present invention is a slide support structure of the tubular body in the exhaust system of the engine in which the tubular body is slidably supported through the spacer made of metal wire. The slide load when the tube body slides relative to the spacer in the axial direction due to thermal expansion or the like is set to 60 kgf or less at room temperature (generally about 20 ° C.). The above-mentioned slide load means a relative initial load in the axial direction when the tube body starts to slide relative to the spacer in the axial direction. The slide load may not be in a state where the engine is actually driven and the exhaust gas is circulating. For example, the axial line between the spacer and the tube is held while the tube is slidably held by a metal wire spacer. The initial load at the time of moving relatively in the direction only needs to satisfy the above requirements. In the present invention, it is desirable that the density of the metal wire spacer is in the range of 2.2 × 10 ³ kg / m ^{3 to} 2.85 × 10 ³ kg / m ³ .

  As described above, the slide load between the tube body and the spacer is set to 60 kgf or less at room temperature, so that the tube body can be favorably supported without generating large frictional noise or abnormal noise as in the conventional example. It becomes possible.

  Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings. FIG. 1 is a partially longitudinal front view showing an embodiment of a slide support structure for a tubular body in an exhaust system of an engine according to the present invention, and FIG. 2 is an enlarged view of a part thereof.

  The present embodiment is applied to an exhaust pipe formed in a hollow double in an exhaust system of an engine such as an automobile. In the figure, 1 is an engine, 2 is an exhaust manifold, 3 is an exhaust pipe, and 4 is a catalyzer. Reference numeral 3a denotes a rear exhaust pipe that guides the exhaust gas purified by the catalyzer 4 to a silencer that is omitted from the rear view of the vehicle body.

  As shown in FIG. 2, the exhaust pipe 3 is formed by an inner pipe 31 and an outer pipe 32 in an inner and outer double, and between the inner and outer pipes 31 and 32 at the upstream and downstream ends of the exhaust pipe 3. Is provided with a short cylindrical spacer 6 made of a metal wire such as stainless wool. In the present embodiment, each spacer 6 is disposed in a ring-shaped recess 32a formed on the inner surface of the outer tube 32, so that the spacer 6 is fixed to the outer tube 32 so as not to be relatively movable in the axial direction. A relative movement (sliding movement) is possible in the axial direction with respect to the tube 31.

  In the figure, 7 is a flange for connection to the exhaust manifold 2 provided at the upstream end of the exhaust pipe 3, and the upstream end of the outer pipe 2 of the exhaust pipe 3 is fixed to the flange 7 by welding or the like. . The catalyzer 4 has a configuration in which the honeycomb catalyst 42 is accommodated in the outer cylinder 41, and the upstream end of the outer cylinder 41 is gradually reduced in diameter so that the outer periphery of the outer pipe 32 at the downstream end of the exhaust pipe 3. And connected by welding or the like omitted in the drawing.

  In this embodiment, the sliding load between the spacer 6 and the inner tube 31 as a tubular body is set to 60 kgf or less. In this case, the spacer 6 is expanded and contracted by the exhaust heat or the like. On the other hand, when the inner pipe 31 is relatively moved in the axial direction, it is possible to prevent generation of a large frictional noise or abnormal noise.

  The slide load refers to the relative initial load in the axial direction when the inner tube 31 as a tubular body starts to slide relative to the spacer 6 in the axial direction as described above. The slide load may not be the state where the engine is actually driven and the exhaust gas is circulated. For example, in the state where the inner tube 31 is slidably held by the spacer 6, the spacer 6 and the inner tube 31 The initial load at the time of relatively moving in the axial direction may satisfy the above requirements.

Further, the density of the metal wire spacer 6 is appropriate, but it is desirable that the density is preferably in the range of 2.2 × 10 ³ kg / m ^{3 to} 2.85 × 10 ³ kg / m ^3. . If it is less than 2.2 × 10 ³ kg / m ³ , there are problems such as rattling or lowering of durability, and if it exceeds 2.85 × 10 ³ kg / m ³ , This is because there is a risk of suddenly producing a loud sliding sound, or in some cases becoming impossible to slide.

  In the above embodiment, the recess 32a is formed on the inner peripheral surface of the outer pipe 32 in the inner / outer double exhaust pipe 3, and the spacer 6 is arranged in the recess 32a so as to be immovably fixed in the axial direction. However, the fixing means of the spacer 6 is appropriate. In the embodiment and the example, the spacer 6 is fixed to the outer tube 32 and the inner tube 31 is supported by the spacer 6 so as to be relatively movable in the axial direction. However, the spacer 6 is fixed to the inner tube 31. The outer tube 32 may be supported by the spacer 6 so as to be relatively movable in the axial direction. Alternatively, the present invention can be applied to one in which both the inner and outer tubes 31 and 32 are supported so as to be independently movable relative to the spacer 6 in the axial direction.

  The present invention is not limited to the double exhaust pipe inside and outside, and can be applied to a single-layer exhaust pipe. Not only the exhaust pipe, but also pipes constituting an exhaust manifold, a catalyzer, a silencer, etc. Any pipe body in the engine exhaust system, such as a pipe to be disposed, which is slidably supported by a metal wire spacer can be applied to various pipe bodies.

  FIG. 3 shows an example thereof, which is applied to a sub-muffler 10 disposed immediately after, for example, a catalytic converter (not shown) on the relatively upstream side of an exhaust system of an automobile engine. The muffler 10 has a configuration in which a sound absorbing material 13 such as stainless wool or glass wool is interposed between an inner tube 11 and an outer tube 12 and an exhaust guide tube 14 is provided inside the inner tube 11. An exhaust pipe 3 a is connected to the exhaust guide pipe 14, and noise in the exhaust introduced into the exhaust guide pipe 14 from the exhaust pipe 3 a is caused by a large number of penetrations formed in the exhaust guide pipe 14 and the inner pipe 11. The sound is absorbed by the sound absorbing material 13 through the holes 14a and 12a and silenced.

  In this example, a spacing cylinder 15 is provided on the inner surface of the end portion of the inner pipe 11, and a spacer 16 made of a metal wire is interposed between the cylinder 15 and the exhaust guide pipe 14. Even in such a configuration, the slide load when the exhaust guide tube 14 or the cylindrical body 15 and the inner tube 11 slide relative to the spacer 16 in the axial direction is set to the above condition. As described above, it is possible to prevent the generation of large frictional noises and abnormal noises during sliding movement, and to favorably support the pipes such as the inner pipe 11 and the exhaust guide pipe 14.

  Assuming the exhaust pipe of FIGS. 1 and 2, the initial load (slide load) when the inner pipe 31 slides relative to the spacer 6 in the axial direction is appropriately changed, and the slide in each case The sound pressure during movement was measured in the vicinity of the spacer 6. The result is shown in FIG. As is clear from FIG. 4, it was found that when the slide load is normal temperature (generally about 20 ° C.) and is 60 kgf or more, the sound pressure level is about 53 dBA or more, which causes noise.

  As described above, the tubular slide support structure in the exhaust system of the engine according to the present invention is a slide of the tubular body in the exhaust system of the engine in which the tubular body is slidably supported through the spacer made of metal wire. In the support structure, the slide load when the tube body slides relative to the spacer relative to the spacer due to thermal expansion or the like is set to be not more than 60 kgf at room temperature, which is large as in the conventional example. This makes it possible to favorably support the pipe body without generating frictional noise or abnormal noise, and is effective in improving the environment such as noise reduction in the interior of the vehicle or the surrounding environment of an automobile or the like.

Explanatory drawing which shows an example of the exhaust system of the engine to which this invention is applied. The partially cut-out enlarged view of the main part of the exhaust system. Sectional drawing which shows the other example of the exhaust system of the engine to which this invention is applied. The graph which shows the relationship between the slide load and sound pressure by the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Exhaust manifold 3, 3a Exhaust pipe 31 Inner pipe 32 Outer pipe 4 Catalyzer 6, 16 Spacer 10 Sub muffler

Claims (2)

  In a slide support structure for a pipe body in an exhaust system of an engine in which the pipe body is slidably supported via a spacer made of a metal wire rod, the pipe body is axially relative to the spacer due to thermal expansion or the like. A slide support structure for a tubular body in an exhaust system of an engine, wherein a slide load at the time of sliding is reduced to 60 kgf or less at room temperature. 2. A pipe body in an exhaust system of an engine according to claim 1, wherein the density of the spacer made of the metal wire is in the range of 2.2 × 10 ³ kg / m ^{3 to} 2.85 × 10 ³ kg / m ^3. Slide support structure.

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