JP2005207381A - Exhaust pipe resonance prevention device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent generation of booming noise inside of a cabin and resonance of steering wheel caused by vibration of exhaust system and to improve efficiency of work for installing both exhaust pipes onto a vehicle body. <P>SOLUTION: This exhaust pipe resonance prevention device has connection pieces 3, 3 for connecting both upstream side protectors 23, 23 projectingly formed on a facing surface side of both upstream side protectors 23, 23 of both flexible tubes 2a, 2b. Fastening holes 3a, 3a long in a projection direction are formed on the connection pieces 3, 3, both flexible tubes 2a, 2b are bound each other by fastening a bolt 4 and a nut 5 inserted through fastening holes 3a, 3a under a condition that both connection pieces are overlapped each other. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust pipe resonance suppression device for restraining resonance by restraining two exhaust pipes connected to an engine to each other.

  Usually, the two exhaust pipes arranged opposite to the engine are each provided with a flexible tube in the middle, and are gathered into one exhaust pipe on the downstream side of both flexible tubes (for example, Patent Document 1). reference.).

Japanese Patent Application Laid-Open No. 6-108841 (Specification (page 3), FIG. 2)

  However, as described above, the vibration of the exhaust pipe is absorbed on the downstream side of the flexible tube by the intervention of the flexible tube, but the heat of the exhaust gas is released on the upstream side of the flexible tube via the bracket. Since it is not fixed to the vehicle body in order to prevent this, there are problems as described below.

  That is, in particular, in the V-type engine in which the exhaust manifold is opposed to the vehicle in the longitudinal direction, both the front and rear exhaust manifolds having different rigidity and the front and rear manifold converters having different weights and lengths are used. As shown by the solid line in (experimental data indicating vibration acceleration amplitude level (dB) with respect to engine rotation speed (rpm)), a large resonance phenomenon occurs over two locations (A part and B part) upstream of the flexible tube, This resonance causes the engine to vibrate through the exhaust manifold, and this vibration causes a vehicle body vibration through the engine mount, and this influence causes a booming noise in the vehicle interior (see section C).

In addition, the resonance of the manifold converter is caused to vibrate the engine through the exhaust manifold, and this vibration causes the steering (handle) to resonate from the transmission via the drive shaft.
The above-described problems can also occur in a V-type engine in which exhaust manifolds are arranged to face each other in the vehicle width direction.

  The problem to be solved by the present invention is that it is possible to suppress the generation of a booming noise and the resonance of the steering wheel due to the vibration of the exhaust system, and to improve the efficiency of the work of assembling both exhaust pipes to the vehicle body. An object of the present invention is to provide an exhaust pipe resonance suppression device capable of performing

  In order to solve the above-mentioned problem, in the exhaust pipe resonance suppression device according to claim 1, a flexible tube is interposed in each of the two exhaust pipes connected to the engine, and the flexible tube includes the bellows portion and the bellows portion. A bellows pipe having straight pipe portions at both ends thereof, an outer blade that is fitted and fixed in a state of covering the outer circumference of the bellows pipe, and a bellows pipe that is fitted and fixed in a state of covering the outer circumference of the outer blade in the straight pipe portions at least at both ends of the bellows pipe. In the exhaust system having a structure in which the two exhaust pipes are inserted and fixed inside the straight pipe portions of the bellows pipe, the two exhaust pipes are mutually restrained to suppress resonance. An exhaust pipe resonance suppression device for performing both of the protectors on opposite surfaces of the upstream protectors in the flexible tubes. Connection portion for forming are protruded respectively, and a means which is characterized in that so as to restrain the two exhaust pipes to each other to each other by connecting and fixing the both connecting portions.

  The exhaust pipe resonance suppression device according to claim 2 is the exhaust pipe resonance suppression device according to claim 1, wherein at least a part of the opening edge of the protector in which the both connecting portions are formed in an annular shape faces outward. The means is formed integrally with the protector by bending.

  The exhaust pipe resonance suppression device according to claim 3 is the exhaust pipe resonance suppression device according to claim 1 or 2, wherein a fastening hole is formed in each of the connection portions, and the connection portions are overlapped with each other. The exhaust pipes are constrained to each other by fastening with bolts and nuts inserted through the fastening holes in a state.

  The exhaust pipe resonance suppression device according to claim 4 is the exhaust pipe resonance suppression device according to claim 3, wherein at least one of the fastening holes formed in both the connecting portions is connected to both. It is formed as a long hole that is long in the protruding direction of the part.

  The exhaust pipe resonance suppression apparatus according to claim 5 is the exhaust pipe resonance suppression apparatus according to any one of claims 1 to 4, wherein the two exhaust pipes of the two systems face each other in the front-rear direction of the vehicle in the engine. It was made the means characterized by being connected to the both exhaust manifolds.

As described above, the exhaust pipe resonance suppression device according to claim 1 restrains the two exhaust pipes connected to the engine from each other by connecting the upstream protectors of the two flexible tubes, In this way, by constraining the two exhaust pipes to each other, the individual rigidity is improved and vibration is suppressed, thereby suppressing the vibration acceleration amplitude level of the large resonance phenomenon that has occurred so far. The resonance in the low rotation region moves to the high rotation region, and the abnormal vibration of the engine is greatly reduced.
Therefore, it is possible to suppress the generation of a booming noise in the vehicle interior and the resonance of the steering wheel due to the vibration of the exhaust system.
Further, by effectively using the protector on the upstream side of the flexible tube, the number of parts can be reduced and the space can be effectively used.

  In the exhaust pipe resonance suppression device according to claim 2, as described above, the both connecting portions bend outwardly at least a part of the opening edge portion of the protector formed in an annular shape. With this configuration, the number of parts can be further reduced and the work efficiency can be increased.

  In the exhaust pipe resonance suppression device according to claim 3, as described above, a fastening hole is formed in each of the two connecting portions, and a bolt inserted into the fastening hole in a state where both the connecting portions are overlapped with each other; By tightening with nuts, both exhaust pipes are restrained from each other, so that the two exhaust pipes are restrained from each other, but in the stage (delivery stage, transport stage) before assembly of the exhaust system to the vehicle body The two exhaust pipes can be preliminarily secured in advance by loosely screwing and temporarily fastening a nut to a bolt inserted through the fastening hole in a state where the two coupling portions are overlapped with each other.

  After the two exhaust pipes are assembled to the vehicle body, the nuts are fastened to the bolts with normal torque and the connecting portions are fastened and fixed, so that the two exhaust pipes are connected to each other via the upstream protector. Can be constrained to each other.

  As described above, since the assembly work to the vehicle body can be performed with both the exhaust pipes temporarily fixed together, the assembly is simplified, thereby improving the efficiency of the assembly work of both exhaust pipes to the vehicle body. The effect of being able to be obtained is obtained.

  In the exhaust pipe resonance suppression device according to claim 4, as described above, at least one of the fastening holes formed in the connecting portions is long in the protruding direction of the connecting portions. By being formed in the hole, the interval between the two exhaust pipes can be finely adjusted when assembled to the vehicle body.

  In the exhaust pipe resonance suppression device according to claim 5, as described above, the two exhaust pipes connected to the two exhaust manifolds arranged opposite to each other in the longitudinal direction of the vehicle in the engine are restrained. Thus, in an engine of a type in which both exhaust manifolds are opposed to each other in the front-rear direction of the vehicle, the length and weight of the exhaust system are greatly different, so that the resonance phenomenon occurring at two locations upstream of the flexible tube is particularly large. However, by constraining the two exhaust pipes to each other, the individual rigidity is improved and vibration is suppressed, so that the vibration acceleration amplitude level of the large resonance phenomenon that has occurred up to now can be suppressed and low. The resonance of the rotation region moves to the high rotation region, and abnormal vibration of the engine is greatly reduced. It is possible to suppress the occurrence and the resonance of the handle of muffled sound.

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

The exhaust pipe resonance suppression device of the first embodiment corresponds to the invention described in claims 1 and 3 to 5.
That is, in the first embodiment, a case will be described in which the exhaust manifold is applied to an exhaust system of a V-type engine that is opposed to the vehicle in the longitudinal direction.

First, the exhaust pipe resonance suppression device of the first embodiment will be described with reference to the drawings.
FIG. 1 is an overall view showing an exhaust system of an engine to which the exhaust pipe resonance suppression device of the first embodiment is applied. A V-type engine 1, a front side exhaust manifold 10a, a rear side exhaust manifold 10b, and a front side Manifold converter 11a, rear manifold converter 11b, front bank side front tube (exhaust pipe) 12a, rear bank side front tube (exhaust pipe) 12b, front bank side flexible tube 2a, rear bank side flexible tube 2b, An underfloor converter 14, a rear tube 15, a pre-muffler 16, branch tubes 17 a and 17 b, rear mufflers 18 a and 18 b, an exhaust system suspension device 19, and an exhaust pipe resonance suppression device A are provided as main components.

  The exhaust pipe resonance suppression device A is configured such that the front bank side front tube 12a and the rear bank side front tube 12b provided together are constrained to each other at the upstream ends of the flexible tubes 2a and 2b, thereby both front tubes 12a and 12b. 2 (disassembled perspective view), FIG. 3 (plan view showing the assembled state with respect to both front tubes), and FIG. 4 (enlarged sectional view of the main part), It is formed integrally with the upstream protectors 23 and 23 in the respective flexible tubes 2a and 2b.

  That is, as shown in FIG. 4, each flexible tube 2a, 2b covers the bellows portion 21a, the bellows tube 21 having the straight tube portions 21b at both ends of the bellows portion 21a, and the outer periphery of the bellows tube 21. The outer blade 22 is mounted and fixed, the upstream protector 23 is mounted and fixed in a state of covering the outer periphery of the outer blade 22 in the straight pipe portions 21b at both ends of the bellows pipe 21, and the downstream protector (not shown). ing.

  And in this Example 1, the connection piece (connection part) for connecting both the upstream protectors 23 and 23 to the opposing surface side of both the upstream protectors 23 and 23 in both the flexible tubes 2a and 2b provided side by side. 3 and 3 are fixed by welding, and the connecting pieces 3 and 3 are formed with fastening holes 3a and 3a which are formed in long holes in the protruding direction of the connecting pieces 3 and 3, respectively.

That is, the exhaust pipe resonance suppression device A is constituted by the pair of upstream protectors 23 and 23 to which the connecting pieces 3 and 3 are fixed, the bolt 4 and the nut 5.
The bolt 4 and the nut 5 are fasteners for fastening the connecting pieces 3 and 3 in a state of being overlapped with each other. The bolt 4 inserted through the fastening holes 3a and 3a is screwed into the nut 5 and fastened. By doing so, both front tubes 12a and 12b are mutually restrained via both the upstream protectors 23 and 23 (refer FIG. 3).

  The exhaust pipe resonance suppression device A restrains both front tubes 12a and 12b on the upstream side of both flexible tubes 2a and 2b, but is provided for the purpose of restraining both flexible tubes 2a and 2b themselves. It is not something that can be done.

Next, operations and effects of the first embodiment will be described.
In the exhaust pipe resonance suppression apparatus A according to the first embodiment, as shown in FIG. 1, the two exhaust systems connected to the V-type engine 1 are mutually restrained, but the stage before the exhaust system is assembled to the vehicle body. In the (delivery stage, transport stage), as shown in FIG. 3, in the state where the two connecting pieces (connecting portions) 3, 3 fixed to the upstream protectors 23, 23 are overlapped with each other, the fastening holes 3a By loosely screwing the bolt 4 inserted through 3a into the nut 5, both front tubes 12a, 12b can be delivered and transported with both front tubes 12a, 12b temporarily fixed.

  Then, after the two front tubes 12a and 12b of the two systems are assembled to the vehicle body, the nuts 5 are tightened to the bolts 4 with normal torque, and the connecting pieces 3 and 3 are fastened and fixed. The front tubes 12a and 12b can be in a state of being restrained from each other via the protectors 23 and 23.

As described above, in the first embodiment, since the assembly work to the vehicle body can be performed in a state where both the front tubes 12a and 12b are temporarily fixed, the assembly is simplified. , 12b can be efficiently mounted on the vehicle body.
Further, by effectively using the protectors 23, 23 on both upstream sides of the flexible tubes 2a, 2b, the number of parts can be reduced and the space can be effectively used.

  Further, the two front tubes 12a and 12b connected to the V-type engine 1 are constrained to each other. Thus, by restricting the two front tubes 12a and 12b to each other, individual rigidity As a result, the vibration acceleration amplitude level of the large resonance phenomenon that has occurred up to now is suppressed, and the resonance in the low rotation region moves to the high rotation region, resulting in significant abnormal vibration of the engine. Reduced to

FIG. 5 is experimental data showing the vibration acceleration amplitude level (dB) with respect to the engine rotation speed (rpm), and is the vertical vibration characteristic of the front position of the front bank side flexible tube 2a as indicated by the dotted line of this experimental data. The resonance of A has moved to A1, and the resonance of B, which is the vertical vibration characteristic at the front position of the rear bank side flexible tube 2b, has moved to B1, and as a result, the front seat noise level C has decreased to max 5 dB. .
Therefore, it is possible to suppress the generation of a booming noise in the vehicle interior and the resonance of the steering wheel due to the vibration of the exhaust system.

  Further, the fastening holes 3a, 3a formed in the both connecting pieces 3, 3 are formed as long holes extending in the protruding direction of the both connecting pieces 3, 3, so that both fronts The distance between the tubes 12a and 12b can be finely adjusted.

  In addition, the two types of front tubes 12a, 12b connected to both exhaust manifolds 10a, 10b opposed to each other in the longitudinal direction of the vehicle in the V-type engine 1 are restrained. In this way, both the exhaust manifolds 10a In the V-type engine 1 of the type in which 10b is opposed to the vehicle in the front-rear direction, the length and weight of the exhaust system are greatly different. Therefore, resonance phenomenon that occurs at two locations upstream of the flexible tubes 2a and 2b occurs. Although especially large, since the two front tubes 12a and 12b are constrained to each other, the individual rigidity is improved and vibrations are suppressed. Therefore, the vibration acceleration amplitude level of the large resonance phenomenon that has occurred so far And the resonance in the low rotation region moves to the high rotation region, causing abnormal engine vibration. Is reduced in width, therefore, it is possible to suppress the occurrence and the resonance of the steering wheel in the passenger compartment of the muffled sound based on the vibration of the exhaust system.

  Next, another embodiment of the present invention will be described. In the description of the other embodiments of the present invention, the same components as those of the first embodiment are not shown or described, or the same reference numerals are given and the description thereof is omitted.

The exhaust pipe resonance suppression device of the second embodiment corresponds to the invention described in claims 1 to 5.
As shown in FIG. 6 (disassembled perspective view) and FIG. 7 (plan view showing the assembled state with respect to both front tubes), the exhaust pipe resonance suppression device of this embodiment 2 It is formed integrally with the protectors 23, 23 by extending a part of both flange portions 31, 31 formed integrally with the downstream opening edge of the upstream protectors 23, 23 formed in an annular shape. This is different from the first embodiment.

  Accordingly, the exhaust pipe resonance suppression device according to the second embodiment has the same effects as the first embodiment, and the connecting portions 3 and 3 are integrally formed with the protectors 23 and 23, respectively. Can be further reduced, and since the welding work is not necessary, an additional effect that the work efficiency can be improved is obtained.

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 a scope not departing from the gist of the present invention are included in the present invention.
For example, in the embodiment, the case where the present invention is applied to the exhaust system of the V-type engine 1 in which the exhaust manifolds 10a and 10b are arranged to face each other in the vehicle front-rear direction has been described, but the exhaust manifold is arranged to face the vehicle width direction of the vehicle. The present invention can also be applied to a V-type engine.

Further, in the embodiment, the fastening holes 3a and 3a formed in the connecting pieces 3 and 3 are formed as long holes, but they may be simple circular holes. Moreover, you may make it form larger diameter than the volt | bolt 4. FIG.
In the embodiment, both the connecting pieces 3 and 3 are fastened and fixed by the bolt 4 and the nut 5, but may be connected and fixed by other methods such as welding.

1 is an overall view showing an engine exhaust system to which an exhaust pipe resonance suppression device of Embodiment 1 is applied. 1 is an exploded perspective view showing an exhaust pipe resonance suppression device of Embodiment 1. FIG. It is a top view which shows the assembly | attachment state with respect to both front tubes which show the exhaust pipe resonance suppression apparatus of Example 1. FIG. It is a principal part expanded sectional view which shows the exhaust pipe resonance suppression apparatus of Example 1. FIG. It is an experimental data which shows the vibration acceleration amplitude level with respect to the engine speed in the vehicle to which the exhaust pipe resonance suppression apparatus of Example 1 was applied. It is a disassembled perspective view which shows the exhaust pipe resonance suppression apparatus of Example 2. FIG. It is a top view which shows the assembly | attachment state with respect to both front tubes which shows the exhaust pipe resonance suppression apparatus of Example 2. FIG.

Explanation of symbols

A Exhaust pipe resonance suppression device 1 V-type engine 2a Front bank side flexible tube 2b Rear bank side flexible tube 3 Connection piece (connection part)
3a Fastening hole 4 Bolt 5 Nut 21 Bellows 21a Bellows part 21b Straight pipe part 21c Straight pipe part 22 Outer blade 23 Upstream protector 10a Front exhaust manifold 10b Rear exhaust manifold 11a Front manifold 11b Rear manifold 12a Front bank side Front tube (exhaust pipe)
12b Rear bank side front tube (exhaust pipe)
14 Underfloor converter 15 Rear tube 16 Pre-muffler 17a Branch tube 17b Branch tube 18a Rear muffler 18b Rear muffler 19 Exhaust system suspension

Claims (5)

A flexible tube is inserted in the middle of the two exhaust pipes connected to the engine.
The flexible tube has a bellows part, a bellows pipe having straight pipe parts at both ends of the bellows part, an outer blade attached and fixed in a state of covering the outer periphery of the bellows pipe, and the outer part in the straight pipe part at least at both ends of the bellows pipe It consists of a protector that is attached and fixed in a state of covering the outer periphery of the blade,
In the exhaust system having a structure in which the two exhaust pipes are inserted and fixed inside the straight pipe portions of the bellows pipe,
An exhaust pipe resonance suppression device for restraining resonance by restraining the two exhaust pipes from each other,
Connecting portions for connecting the two protectors to each other on the opposite surface side of the two protectors on the upstream side in the two flexible tubes are respectively formed protruding.
An exhaust pipe resonance suppression device characterized in that the exhaust pipes are constrained to each other by connecting and fixing the fastening portions.   2. The exhaust pipe resonance suppression device according to claim 1, wherein both the connecting portions are integrally formed with the protector by bending outward at least a part of an opening edge of the annular protector. An exhaust pipe resonance suppression device characterized by comprising: The exhaust pipe resonance suppression device according to claim 1 or 2, wherein a fastening hole is formed in each of the connecting portions,
An exhaust pipe resonance suppression device characterized in that the exhaust pipes are constrained to each other by fastening them with bolts and nuts inserted into fastening holes in a state in which both the connecting parts are overlapped with each other.   4. The exhaust pipe resonance suppression device according to claim 3, wherein at least one of the fastening holes formed in the connecting portions is formed as a long hole that is long in the protruding direction of the connecting portions. An exhaust pipe resonance suppression device characterized by that.   The exhaust pipe resonance suppression device according to any one of claims 1 to 4, wherein the two exhaust pipes of the two systems are connected to both exhaust manifolds disposed opposite to each other in the front-rear direction of the vehicle in the engine. A feature of the exhaust pipe resonance suppression device.

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