JP2000274236A - Vibration-absorbing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of noise and increase in cost after used for a long time of use. SOLUTION: This vibration-absorbing mechanism 10 comprises a flexible pipe 11, outer pipe 12, inner pipe 13 and blade 14. When excessive extensional force or compression force is applied to this vibration absorbing mechanism 10, the blade 14 for connecting the outer pipe 12 and the inner pipe 13 restrains both movements of the flexible pipe 11 in the directions to extend and compress the flexible pipe 11, therefore, the flexible pipe 11 will not be extended too for and will not be damaged. In addition, one blade is sufficient as against each one blade inside and outside in a conventional mechanism, simplifying the structure and decreasing manufacturing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration absorbing mechanism for absorbing vibration generated in an exhaust passage of an engine in the middle of the exhaust passage.

[0002]

2. Description of the Related Art It is known that the exhaust path of an engine receives vibrations caused by rolling, pitching and the like of the engine or vibrations when traveling on rough roads. The exhaust pipe may flex repeatedly and eventually break. Therefore, in order to solve such a problem, a vibration absorbing mechanism has been provided in the middle of the exhaust path. A typical example of the vibration absorbing mechanism is a flexible pipe (also referred to as a serpentine pipe or a bellows pipe), which has a function of absorbing vibration against bending and vibration in the axial direction.

[0003] As such a vibration absorbing mechanism, one disclosed in Japanese Patent Application Laid-Open No. 6-221145 is known.
This mechanism, as shown in FIG.
02, an inner sleeve 104 and an outer sleeve 105
Are provided so as to be coaxial, and both sleeves 104, 1
A spacer 106 made of a wire mesh is arranged in a gap between overlapping portions 05. In this vibration absorbing mechanism, the flexible pipe 102 expands when it receives an extension force, and the inner sleeve 104 and the outer sleeve 105 slide away from each other via the spacer 106, and conversely, the flexible pipe 102 contracts when it receives a compression force. At the same time, the inner sleeve 104 slides into the outer sleeve 105 via the spacer 106. In any case, when the flexible pipe 102 is deformed and the spacer 106 and each of the sleeves 104 and 105 slide, the acting force (extension force, compression force) is attenuated and the vibration is absorbed. However, since the vibration absorbing mechanism uses the spacer 106 made of a wire mesh, the spacer 106 may be dislodged when used for a long period of time.
There is a possibility that a gap is generated between the sleeves 104 and 105 and the spacer 106 collides with each of the sleeves 104 and 105 when sliding to generate abnormal noise.

On the other hand, as disclosed in Japanese Patent Application Laid-Open No. 10-299476, a type of vibration absorbing mechanism not using a wire mesh has been known. In this vibration absorbing mechanism, as shown in FIG.
1 a and an end 202 a of the second pipe 202 are connected by a flexible pipe 203 and an outer blade 204. Further, a holding tube 205 is fixed to an end 201 a of the first pipe 201, and a distal end thereof extends toward an end 202 a of the second pipe 202. Further, a blade holding tube 206 is fixed to an end portion 202 a of the second pipe 202, and a tip end of the blade holding tube 206 is attached to an end portion 201 of the first pipe 201.
a. Both ends are overlapped with a gap therebetween and connected by an inner blade 207. When an excessive tensile force acts on the flexible pipe 203, a tensile force acts on the outer blade 204 to suppress the expansion of the flexible pipe 203. On the other hand, when an excessive compressive force acts on the flexible pipe 203, a tensile force acts on the inner blade 207 to suppress the compression of the flexible pipe 203. According to this vibration absorbing mechanism, since no wire mesh is employed, there is no possibility that the above-described abnormal noise is generated.

[0005]

SUMMARY OF THE INVENTION Japanese Patent Application Laid-Open No. 10-2994
No. 76, the two blades 204, 2
No. 07 has different effects, whereby even if an excessive tensile force / compressive force is inputted to the flexible pipe 203 for the first time, the effect of preventing breakage due to the force is obtained.
Both are indispensable for the vibration absorbing mechanism.

However, the flexible pipe 203
Expensive blades 204,20 both on the outside and inside
7, there is a problem that the cost of the vibration absorbing mechanism is increased. In addition, since the holding pipe 206 is provided inside the flexible pipe 203 and the holding pipe 205 is further provided inside the flexible pipe 203, the cross-sectional area of the exhaust gas flow path decreases rapidly from the first pipe 201 to the holding pipe 205. Also, there was a risk that the back pressure would rise.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a vibration absorbing mechanism that does not generate abnormal noise even when used for a long period of time and does not increase the cost. Another object of the present invention is to provide a vibration absorbing mechanism that does not cause an increase in back pressure.

[0008]

Means for Solving the Problems and Effects of the Invention In order to solve the above problems, the present invention relates to a vibration absorbing mechanism for absorbing vibration generated in an exhaust path of an engine in the middle thereof. A flexible pipe capable of bending and expanding and contracting the cut exhaust path, and one end fixed to one end of the flexible pipe and the other end extending toward the other end of the flexible pipe to become a free end. And a second pipe having a portion having one end fixed to the other end of the flexible pipe and having a gap between the first pipe and the other end of the first pipe in a direction orthogonal to the pipe axis.
A pipe, and a blade connecting the other end of the first pipe and the portion of the second pipe, wherein the flexible pipe is expanded or contracted by a tensile force even when the flexible pipe is expanded or contracted by a tensile force. It is characterized in that the blade regulates expansion and contraction of the flexible pipe by the action of a tensile force.

According to the present invention, when the flexible pipe is stretched by receiving an excessive tensile force, the one end and the other end of the flexible pipe initially move in a direction away from each other. When the flexible pipe extends in this manner, the first pipe and the second pipe move in a direction away from each other, and eventually the first pipe and the second pipe move.
The blade connecting the pipe and the second pipe is pulled, and a tensile force acts on this blade. Then, the tensile force prevents the movement of the first pipe and the second pipe from moving away from each other, and thus the movement of the flexible pipe. On the other hand, when the flexible pipe contracts by receiving an excessive compressive force, the one end and the other end of the flexible pipe initially move in a direction approaching each other. When the flexible pipe shrinks in this manner, the first pipe and the second pipe move in a direction approaching each other, and finally, a blade connecting the first pipe and the second pipe is pulled, and a tensile force acts on this blade. . Then, the pulling force prevents the first pipe and the second pipe from moving toward each other, and thus the movement of the flexible pipe.

According to the present invention, even if an excessive extension force or compression force acts on the vibration absorbing mechanism of the present invention, the blade restricts both the movement in the extension direction and the movement in the compression direction of the flexible pipe. The flexible pipe does not break. In order to prevent the flexible pipe from being damaged by restricting both the expansion and the compression of the flexible pipe with one blade, the flexible pipe is damaged by the two blades as in the conventional vibration absorbing mechanism (see FIG. 10). The structure is simpler and the manufacturing cost is lower than in the case of prevention. Further, in the conventional vibration absorbing mechanism using a wire mesh (see FIG. 9), there is a problem that an unusual sound is generated when the wire mesh is sagged due to long-term use. In the present invention, the wire mesh is used. No such noise is generated.

In the present invention, in order for the blade to control both the expansion and the compression of the flexible pipe, for example, the axial deviation width between the blade-first pipe connection point and the blade-second pipe connection point is determined. , May be set to be smaller than the maximum amplitude of the vibration to be absorbed. In this case, if the vibration exceeds the maximum amplitude of the vibration to be absorbed, a tensile force acts on the blade, thereby restricting the movement of the flexible pipe in the direction of extension and compression.

Further, the shift width may be substantially zero. At this time, the blade has an annular surface substantially orthogonal to the pipe axis of the flexible pipe. In this case, when a certain amount of vibration in the direction of expansion and contraction is applied to the vibration absorbing mechanism, the free end of the first pipe is bent, or the mesh is deformed when the braid is made of a metal wire. By doing so, the flexible pipe expands and contracts in the pipe axial direction. However, when excessive vibration is applied, a tensile force acts on the blade to restrict the expansion and contraction operation of the flexible pipe.

In the present invention, the first pipe may be formed so as to cover the flexible pipe from the outside, and the second pipe may be formed so as to cover the flexible pipe from the inside. In this case, the first pipe plays a role of protecting the flexible pipe from curbs, stepping stones and the like, and the second pipe plays a role of protecting the flexible pipe from heat damage caused by exhaust gas. Further, since the other end of the first pipe can have the same diameter as the outermost shell of the flexible pipe, and the one end of the second pipe can have the same diameter as the inner diameter of the flexible pipe, the appearance of the apparatus becomes compact. . Furthermore, since the cross-sectional area of the exhaust gas flow path is not reduced as compared with the case where the first pipe and the second pipe are provided inside the flexible pipe, it does not cause a rise in back pressure.

In the present invention, as the blade, for example, a net made of a fine wire net may be used, or a blade in which a plurality of thin metal plates are radially attached may be used. Also,
The blade may be taut in an unused state or may be taut in a slightly bent state.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a cutaway view of this embodiment, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is an explanatory view of a blade. The vibration absorbing mechanism 10 of the present embodiment includes:
It is composed of a flexible pipe 11, an outer pipe 12, an inner pipe 13, and a blade 14.

The flexible pipe 11 is a flexible coil made of metal, and its pipe wall does not allow fluid to pass therethrough. The flexible pipe 11 has a shape in which peaks and valleys are repeated, and therefore can be bent and expanded and contracted. The outer pipe 12 corresponds to the first pipe of the present invention, and is a stepped pipe disposed coaxially with the flexible pipe 11, and has a small diameter portion 12a and a large diameter portion 12b.
And Among them, one end of the outer pipe 12, that is, the end of the small diameter portion 12a, is closely attached and fixed to one end of the flexible pipe 11, that is, the outer peripheral surface of the downstream end 11b. On the other hand, the large-diameter portion 12b is formed so as to extend toward the other end of the flexible pipe 11, that is, the upstream end 11a, and to cover the peaks and valleys of the flexible pipe 11 from outside. The other end of the outer pipe 12, that is, the end 12c of the large diameter portion 12b is a free end. Furthermore, the large diameter portion 12b of the outer pipe 12 is
It is designed to have a slightly larger diameter than the outermost shell.

The inner pipe 13 corresponds to a second pipe of the present invention, is a stepped pipe disposed coaxially with the flexible pipe 11, and has a large diameter portion 13a and a small diameter portion 13b. . Among these, one end of the inner pipe 13, that is, the end of the large diameter portion 13 a is connected to the flexible pipe 1.
1 is closely attached and fixed to the inner peripheral surface of the upstream end portion 11a. On the other hand, the small diameter portion 13b is formed so as to extend inside the flexible pipe 11 and cover the peaks and valleys of the flexible pipe 11 from inside. The large diameter portion 13a of the inner pipe 13 and the end 12c of the outer pipe 12
And a gap in a direction perpendicular to the pipe axis is formed between the two. The small-diameter portion 13b of the inner pipe 13 is designed to have a diameter slightly smaller than the inner diameter of the flexible pipe 11.

The blade 14 is a member for connecting the large diameter portion 12b of the outer pipe 12 and the large diameter portion 13a of the inner pipe 13. The blade 14 is a net made of a thin metal wire, and includes a first cylindrical portion 14a, an annular surface portion 14b, and a second cylindrical portion 14c.
And The first cylindrical portion 14 of the blade 14
a is mounted on the large-diameter portion 13a of the inner pipe 13 via the upstream end 11a of the flexible pipe 11, and the outer periphery thereof is wound and fixed by the first band 15. The second cylindrical portion 14c is exteriorly provided on the large diameter portion 12b of the outer pipe 12, and the outer periphery thereof is wound and fixed by the second band 16. The annular surface portion 14b is substantially perpendicular to the pipe axis of the flexible pipe 11.

The end 15a of the first band 15 that contacts the blade 14 is bent outward so that the edge does not directly contact the blade 14, and the end 12c of the outer pipe 12 that contacts the blade 14 is also the edge. Are bent inward so as not to directly hit the blade 14. Also, a connection point P between the blade 14 and the outer pipe 12
The axial displacement between the blade and the connection point Q between the blade 14 and the inner pipe 13 is set to substantially zero. This connection point P
And the connection point Q are separated by a predetermined distance in a direction perpendicular to the pipe axis.

Next, the operation of the vibration absorbing mechanism 10 will be described. FIG. 4 is an explanatory diagram of an exhaust path of an engine to which the vibration absorbing mechanism is applied. As shown in FIG. 4, the exhaust path 30 of the engine includes an exhaust manifold 32, a catalytic converter 33, and a sub-muffler 3 attached to the engine.
4. It is composed of a main muffler 35, and each device is connected to each other via an exhaust pipe. For example, when the vibration frequency of the engine reaches a certain frequency, the exhaust path 30 of the engine oscillates between a specific deformation mode indicated by a dotted line in FIG. Of these, the vibration absorbing mechanism 10 of the present embodiment is installed at the locations (ie, antinodes) A and B where vibrations are greatest.

In the vibration absorbing mechanism 10, the flexible pipe 11 has a hermetic property, and the large diameter portion 13 a of the inner pipe 13 is in close contact with the flexible pipe 11. Further, at the connection points A and B, the vibration absorbing mechanism 10 is connected with good hermeticity. In FIG. 1, an upstream exhaust pipe (not shown) is inserted so as to be inscribed in the large-diameter portion 13a of the inner pipe 13, and a downstream exhaust pipe (not shown) is inscribed in the downstream end 11b of the flexible pipe 11. Inserted. Therefore, portions A and B of the exhaust path 30 of the engine that are connected by the vibration absorbing mechanism 10
In, the exhaust gas flows from the upstream side to the downstream side without leaking to the outside.

The vibration absorbing mechanism 10 installed as described above
Indicates that the flexible pipe 11
The width of the peaks and valleys of the
Ends 11a, 11b move in directions away from each other and extend. Conversely, when a compressive force is applied, the widths of the peaks and valleys of the flexible pipe 11 become narrower, and both ends 11a and 11b of the flexible pipe 11 move in directions approaching each other and shrink. When the widths of the peaks and valleys increase or decrease in this way, the vibration generated in the exhaust path 30 is attenuated due to energy consumption due to the wide and narrow deformation.

When vibration having an unexpectedly large amplitude is applied to the vibration absorbing mechanism 10, the following operation is performed. That is, when the flexible pipe 11 is stretched by receiving the tensile force due to the vibration, the outer pipe 12 and the inner pipe 13 are separated from each other while the mesh of the blade 14 is deformed or the end 12c of the outer pipe 12 is deformed. It moves, but finally the outer pipe 1
The blade 14 connecting the inner pipe 2 and the inner pipe 13 is pulled, and a tensile force acts on the blade 14. Then, the outer pipe 12 and the inner pipe 1
3 are prevented from moving away from each other, and thus the flexible pipe 11 is prevented from moving. On the other hand, when the flexible pipe 11 contracts by receiving the compressive force, the outer pipe 12 and the inner pipe 13 initially move in a direction approaching each other, and finally, the blade 14 connecting the outer pipe 12 and the inner pipe 13 is pulled, and this blade is pulled. A tensile force acts on 14. Then, the pulling force prevents the outer pipe 12 and the inner pipe 13 from moving toward each other, and thus the movement of the flexible pipe 11 is prevented.

According to the vibration absorbing mechanism 10 described in detail above,
The following effects are obtained. Even if an excessive extension force or compression force acts on the vibration absorbing mechanism 10, the blade 14 connecting the outer pipe 12 and the inner pipe 13 restricts both the movement in the extension direction and the movement in the compression direction of the flexible pipe 11. To do
The flexible pipe 11 does not greatly expand and contract, and there is no possibility of breakage. And one blade 1
In order to prevent the flexible pipe 11 from being damaged by restricting both expansion and compression of the flexible pipe 11 at 4, the conventional method uses two blades to prevent the flexible pipe 11 from being damaged (see FIG. 10). The structure is simple and the manufacturing cost is low. Conventional vibration absorbing mechanism using wire mesh (Fig. 9
In the vibration absorbing mechanism 10 of the present embodiment, the wire mesh is not used. Does not occur. Since the contact portion with the blade 14, that is, the end 15a of the first band 15 and the end 12c of the outer pipe 12 are all bent so that the edge does not hit, the blade 14 may be damaged by the edge during use. Absent. The outer pipe 12 protects the flexible pipe 11 from curbs and stepping stones by covering the flexible pipe 11 from the outside, and the inner pipe 13 protects the flexible pipe 11 from the heat damage caused by the exhaust gas by covering the flexible pipe 11 from the inside. Noise caused by hitting the head). Since the blades 14 are provided outside the flexible pipe 11, the cross-sectional area of the exhaust gas channel is not reduced, and does not cause a rise in back pressure. Since the large-diameter portion 12b of the outer pipe 12 has a diameter slightly larger than the outermost shell of the flexible pipe 11, the entire vibration absorbing mechanism 10 becomes compact and can be installed even in a small space.

[Second Embodiment] FIG. 5 is a cutaway view of the present embodiment. The vibration absorbing mechanism 50 of the present embodiment includes a flexible pipe 51, a first outer pipe 52, a second outer pipe 53, an inner pipe 54, and a blade 55.

The flexible pipe 51 and the inner pipe 54 are substantially the same as the flexible pipe 11 and the inner pipe 13 of the first embodiment, respectively, and a description thereof will be omitted. The first outer pipe 52 corresponds to the first pipe of the present invention, is a stepped pipe disposed coaxially with the flexible pipe 51, and has a small diameter portion 52a.
And a large diameter portion 52b. Among them, one end of the first outer pipe 52, that is, the end of the small diameter portion 52a, is closely attached and fixed to one end of the flexible pipe 51, that is, the outer peripheral surface of the downstream end 51b. On the other hand, the large-diameter portion 52b is formed so as to extend toward the other end of the flexible pipe 51, that is, the upstream end 51a, and to cover about half of the peaks and valleys of the flexible pipe 51 from the outside. The other end 52c of the outer pipe 52 is a free end.

The second outer pipe 53 corresponds to the second pipe of the present invention, is a stepped pipe disposed coaxially with the flexible pipe 51, and has a small diameter portion 53a and a large diameter portion 53b. I have. One end of the second outer pipe 53, that is, the small diameter portion 53 a, is in close contact with and fixed to the outer peripheral surface of the upstream end 51 a of the flexible pipe 51. On the other hand, the large-diameter portion 53b is formed so as to extend toward the downstream end 51b of the flexible pipe 51 and cover approximately half of the peaks and valleys of the flexible pipe 51 from the outside. The other end 53c is a free end. Large diameter portion 53 of second outer pipe 53
b is smaller in diameter than the large diameter portion 52b of the first outer pipe 52, and the end 53c of the second outer pipe 53 and the end 52c of the first outer pipe 52 are arranged at a distance in a direction perpendicular to the pipe axis. I have.

The blade 55 is a member for connecting the other end 52c of the first outer pipe 52 and the other end 53c of the second outer pipe 53, and has an annular surface 55b substantially perpendicular to the pipe axis of the flexible pipe 51. This blade 5
Although the configuration of the blade 5 is different from that of the blade 14 of the first embodiment, its description is omitted.

Next, the operation of the vibration absorbing mechanism 50 will be described. As in the first embodiment, the vibration absorbing mechanism 50 can be used by being installed at the installation locations A and B in FIG. 4, and the width of the peaks and valleys of the flexible pipe 51 can be deformed to be wide and narrow. This is to attenuate the vibration generated in the exhaust path 30 due to the energy consumption and the like. Further, when vibration having an unexpectedly large amplitude is applied to the vibration absorbing mechanism 50, the following operation is performed. That is, when the flexible pipe 51 is stretched by receiving the tensile force due to the vibration, the mesh of the blade 55 is deformed at first, and the end 52c of the first outer pipe 52 or the end 53c of the second outer pipe 53 is bent, and both ends are bent. Outer pipe 52,
The blades 53 move away from each other, but eventually the blade 55 is pulled, and a tensile force acts on the blade 55. Then, both outer pipes 52, 5 are caused by this tensile force.
3 are prevented from moving away from each other, and thus the movement of the flexible pipe 51 is prevented. On the other hand, when the flexible pipe 51 contracts due to the compressive force, the outer pipes 52 and 53 initially move in a direction approaching each other, but finally the blade 55 is pulled and a tensile force acts on the blade 55. Then, the movement of the outer pipes 52 and 53 approaching each other is prevented by the tensile force, and the movement of the flexible pipe 51 is further prevented. According to the vibration absorbing mechanism 50, the effects of the first embodiment described above can be obtained.

[Third Embodiment] FIG. 6 is a partial sectional view of the present embodiment. The vibration absorbing mechanism 70 of the present embodiment includes a flexible pipe 71, a first inner pipe 72, a second inner pipe 73, and a blade 74.
Flexible pipe 71 and first inner pipe 72
Are almost the same as the flexible pipe 11 and the inner pipe 13 of the first embodiment, respectively, and the description thereof will be omitted. Note that the first inner pipe 72 corresponds to the first pipe of the present invention. The second inner pipe 73 corresponds to the second pipe of the present invention, and is a pipe disposed coaxially with the flexible pipe 71. This second inner pipe 73 is a downstream end 71 of the flexible pipe 71.
b, and the downstream end 72 of the first inner pipe 72.
c with a gap in the radial direction. The blade 74 is connected to the downstream end 72 of the first inner pipe 72.
It is a member that connects the second inner pipe 73 and the inner pipe 73 and has an annular surface portion 74b that is substantially perpendicular to the pipe axis of the flexible pipe 71. The configuration of the blade 74 is the same as that of the blade 14 of the first embodiment, and a description thereof will be omitted. The vibration absorbing mechanism 70 operates in substantially the same manner as in the first embodiment, and obtains the above-described effects of the first embodiment.

The embodiments of the present invention are not limited to the above-mentioned embodiments at all, and it goes without saying that various forms can be adopted as long as they fall within the technical scope of the present invention. For example, in the first embodiment, the heat-resistant thin metal wire net shown in FIG. 3A is used as the blade 14, but instead, for example, a thin metal plate strip shown in FIG. May be installed plurally. In this case, the same operation and effect as those of the first embodiment can be obtained. The same can be said for the second and third embodiments.

In the first embodiment, the connection points P and Q
Is substantially zero, but it is sufficient to set the width d to be smaller than the maximum amplitude Am of the vibration to be absorbed (d <Am) as shown in FIG. In this case, if the flexible pipe 11 attempts to expand and contract beyond the maximum amplitude Am, a tensile force acts on the blade 14 to prevent it, so that even if an excessive tensile force / compressive force is input, the flexible pipe 11 may be damaged. Can be prevented. In addition, since the flexible pipe 11 can be expanded and contracted by the fact that the large-diameter portion 12b of the outer pipe 12 is bent or the mesh of the blade 14 is deformed, the shift width d is set in consideration of this point. (Eg, d <(Am
-Α): α is a value determined in consideration of the above points). The same applies to the second and third embodiments.

Further, in the first embodiment, the blade 14 is provided on the upstream side of the vibration absorbing mechanism 10, but the outer pipe 12 is mounted in the opposite direction as shown in FIG.
4 may be provided on the downstream side. In this case, the same operation and effect as those of the first embodiment can be obtained.

[Brief description of the drawings]

FIG. 1 is a cutaway view of a first embodiment.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is an explanatory diagram of a blade.

FIG. 4 is an explanatory diagram illustrating an exhaust path of an engine.

FIG. 5 is a sectional view of a second embodiment.

FIG. 6 is a partial sectional view of a third embodiment.

FIG. 7 is an explanatory diagram relating to a shift width of a connection point.

FIG. 8 is an explanatory diagram of another embodiment.

FIG. 9 is a sectional view of a conventional example.

FIG. 10 is a cutaway view of another conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... vibration absorption mechanism, 11 ... flexible pipe, 12 ... outer pipe, 13 ... inner pipe, 14 ... blade, 14b ... annular surface part, 15
... 1st band, 16 ... 2nd band, 30 ...
Exhaust path, 32 ... exhaust manifold, 33
..Catalytic converter, 34 ... sub muffler, 35 ..
-Main muffler, P, Q ... connection point.

Claims (4)

[Claims] 1. A vibration absorbing mechanism for absorbing vibration generated in an exhaust path in the middle of an exhaust path of an engine, comprising: a flexible pipe that is capable of bending and expanding and contracting the cut exhaust path; Is fixed to one end of the flexible pipe and the other end extends toward the other end of the flexible pipe and is a free end; and one end is fixed to the other end of the flexible pipe. A second pipe having a gap between the other end of the first pipe and a direction perpendicular to the pipe axis; and a blade connecting the other end of the first pipe and the spot of the second pipe. When the flexible pipe expands under a tensile force or shrinks under a compressive force, a tensile force acts on the blade so that the blade is Vibration absorbing mechanism, characterized in that to regulate the expansion and contraction. 2. The axial displacement between the blade-first pipe connection point and the blade-second pipe connection point is set to be smaller than the maximum amplitude of vibration to be absorbed. The vibration absorbing mechanism according to claim 1, wherein: 3. The vibration absorbing mechanism according to claim 1, wherein the blade has an annular surface substantially perpendicular to a pipe axis of the flexible pipe. 4. The apparatus according to claim 1, wherein said first pipe is formed so as to cover said flexible pipe from outside, and said second pipe is formed so as to cover said flexible pipe from inside. The vibration absorbing mechanism according to any one of the above.