JPH10259719A - Vibration absorbing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration absorbing mechanism suitable for reduction of size and having high damping efficiency. SOLUTION: When a tensile force is applied to this vibration absorbing mechanism 10, upper stream and downstream casings 18 and 20 separate away from each other and the width of the crest part 12a of a flexible pipe 12 increases. Reversely, when a compression force is applied, the two casings 18 and 20 approach each other and the width of the crest part 12a decreases. When, as noted above, the width of the crest part 12a changes, through slide between a spacer 16 and a flexible pipe 12 and slide between the spacer 16 and an inner pipe 14, energy is consumed and damped. In this case, since the spacer 16 is inserted in the crest part 12a of the flexible pie 12, the contacting area between the spacer 16 and the flexible pipe 12 is large, thus energy consumption by slide therebetween is high and damping efficiency is also high.

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 a rough road. The pipe may flex repeatedly and eventually break.

For this reason, 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 or a flexible pipe, which has a function of absorbing vibrations in bending and vibrations in an axial direction.

As such a vibration absorbing mechanism, for example, one disclosed in Japanese Patent Application Laid-Open No. Hei 6-221145 has been known. In this vibration absorbing mechanism, an inner sleeve 104 and an outer sleeve 105 are provided coaxially inside a bellows 102 which is a flexible pipe, and a spacer 106 is disposed in a gap between the overlapping portions of the two sleeves 104 and 105. Things. Note that the inner sleeve 104 is located on the upstream side of the exhaust gas.

When this vibration absorbing mechanism receives an extension force,
As the bellows 102 expands, the inner sleeve 104 and the outer sleeve 105 slide away from each other via the spacer 106.
As the 2 contracts, the inner sleeve 104 slides into the outer sleeve 105 via the spacer 106. Also, when subjected to a bending force perpendicular to the longitudinal direction,
The inner sleeve 104 moves in the bending direction with respect to the outer sleeve 105 while the spacer 106 is deformed. In any case, the bellows 102 is deformed, and the spacer 106 and the expanding sleeves 04 and 105 slide, thereby attenuating the acting force (extension force, compression force, bending force) and absorbing the vibration.

[0006]

However, in order to increase the damping in the vibration absorbing mechanism, the spacer 106 is made longer in the longitudinal direction and the inner sleeve 104 is made longer.
It is conceivable to increase the contact area (that is, sliding area) with the outer sleeve 105. However, if the spacer 106 is lengthened in the longitudinal direction, the vibration absorbing mechanism itself becomes large, which is not preferable. there were.

In the exhaust path of the engine, the exhaust path is inherently vibrated and deformed due to the vibration of the engine and the like. Therefore, it is preferable to prevent the vibration caused by this inherent deformation mode. Therefore, it is desired that the device be further downsized as compared with the case where it is mounted near the exhaust port of the engine.

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 which is suitable for miniaturization and has high damping efficiency. It is another object of the present invention to provide a vibration absorbing mechanism for preventing vibration caused by a unique deformation mode of an exhaust path, in addition to the above-mentioned object.

[0009]

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 having one or a plurality of peaks; a small-diameter sleeve disposed inside the flexible pipe with a gap therebetween; and a small-diameter sleeve being in contact with both at a gap between the flexible pipe and the small-diameter sleeve. And a vibration absorbing spacer partially inserted into at least one ridge of the flexible pipe.

When an extension force is applied to such a vibration absorbing mechanism, the width of the peak portion of the flexible pipe (that is, the interval in the axial direction of the flexible pipe) increases. Conversely, when a compressive force is applied, the width of the peak portion of the flexible pipe becomes narrow. Here, in the vibration absorbing mechanism of the present invention, as shown in FIG. 5A, a vibration absorbing spacer (length L) is inserted into at least one mountain portion of the flexible pipe and is in contact with the inner wall thereof. Therefore, the contact area between the vibration absorbing spacer and the flexible pipe is larger than in the case where the same length is not inserted into the inside of the mountain portion (see FIG. 5B). Therefore, when the peak of the flexible pipe is about to expand due to the extension force or to narrow due to the compression force, the sliding area between the vibration absorbing spacer and the flexible pipe is large, resulting in large energy consumption and damping efficiency. Also increases.

Similarly, when a bending force or a torsion force acts on the flexible pipe, the sliding area between the vibration absorbing spacer and the flexible pipe is large, so that the energy consumption is large and the damping efficiency is large. In addition, since the vibration absorbing spacer is inserted inside the peak of the flexible pipe, it is not necessary to install the vibration absorbing spacer at a position different from the peak, and the length of the vibration absorbing mechanism can be shortened accordingly. .

As described above, according to the vibration absorbing mechanism of the present invention, it is possible to obtain an effect that the efficiency of attenuating the vibration is high and an effect that it is suitable for miniaturization. The vibration absorbing mechanism of the present invention is usually provided so as to connect an upstream exhaust pipe and a downstream exhaust pipe that form an exhaust path of an engine. Then, the exhaust gas introduced from the upstream exhaust pipe plays a role of sending the exhaust gas to the downstream exhaust pipe without leaking to the outside, and plays a role of not transmitting the vibration of one exhaust pipe to the other exhaust pipe.

As the vibration absorbing spacer of the present invention, any spacer formed of a material which can be elastically deformed, for example, can be used. Specifically, a spacer formed of an elastomer such as rubber, A spacer formed of a metal fiber or the like can be used. Among them, spacers made of metal fibers are preferable in consideration of heat resistance and the like. Specifically, it is preferable to use a wire mesh or the like.

[0014] The vibration absorbing mechanism of the present invention may be mounted in the middle of the exhaust path of the engine and at the antinode of the unique deformation mode of the exhaust path. In general, the exhaust path of the engine has a unique deformation mode in which it oscillates and resonates at a certain frequency. This vibration can be effectively absorbed, and the effect of suppressing the resonance can be obtained. When mounting on the antinode of such a deformation mode, the mounting space is often limited, but the present invention can be suitably mounted even in such a mounting location because the attenuation efficiency is high even if the size is reduced. be able to.

Further, in the vibration absorbing mechanism of the present invention, the flexible pipe may have only one peak. In this case, since the length of the flexible pipe can be reduced, it is suitable for further miniaturization. Further, since the structure is simple, it can be manufactured at low cost. Furthermore, in the vibration absorbing mechanism of the present invention, the flexible pipe may include a regulating mechanism that regulates a moving range in the extension direction or the compression direction. In this case, as compared with the case where the movable member can be freely moved in the direction of expansion and contraction, there is obtained an effect that the flexible pipe and the vibration absorbing spacer are not likely to be damaged even when an irregularly-sized extension or compression force is applied. Can be

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a sectional view of a vibration absorbing device according to the present embodiment.

The vibration absorbing device 10 of the present embodiment includes a flexible pipe 12, an inner pipe 14, a spacer 16, an upstream casing 18, and a downstream casing 20. The flexible pipe 12 is a bellows made of metal, and its pipe wall does not allow passage of fluid. The flexible pipe 12 has only one peak portion 12a.
Can expand and contract by being deformed in the width direction (left and right direction in FIG. 1).

The inner pipe 14 is a stepped pipe disposed coaxially with the flexible pipe 12, and has a small-diameter sleeve 14a and a large-diameter sleeve 14b. Of these, the small-diameter sleeve 14a is arranged with a gap from the flexible pipe 12, and the large-diameter sleeve 14a
b is the upstream side of the flexible pipe 12 (the left side in FIG. 1,
(The same applies to the following). Downstream of the inner pipe (right side in FIG. 1, the same applies hereinafter)
Of the flexible pipe 12 extends to a position short of the downstream opening 12c.

As the spacer 16, it is preferable to use a metal member which is excellent in heat resistance and is durable and capable of absorbing a stretching force, a bending force, and a twisting force. Therefore, a wire mesh is employed here. The spacer 16 is arranged so as to be in contact with the flexible pipe 12 and the small-diameter sleeve 14 a of the inner pipe 14 in a gap therebetween. Also, the spacer 16
Is partially projected and inserted into the ridge 12a of the flexible pipe 12 so as to contact the inner wall of the ridge 12a.

The spacer 16 may be formed in such a shape by integral molding. However, when the spacer 16 is divided into a plurality of parts so as to be easily inserted into the inside of the mountain part 12a, the spacers 16 are combined. Such a shape may be adopted. The spacer 16 may be provided in a ring shape, that is, over the entire circumference of the small-diameter sleeve 14a, or may be provided in a spot shape along the outer circumference of the small-diameter sleeve 14a.

The upstream casing 18 is provided with the upstream collar 1.
8a, an upstream cover 18b having a diameter larger than that of the upstream collar 18a, and an upstream taper 18c between the upstream collar 18a and the upstream cover 18b. The upstream collar 18a is fixed to the outer peripheral surface of the upstream opening 12b of the flexible pipe 12, and the upstream cover 18
b is provided so as to cover the peak portion 12a of the flexible pipe 12.

The downstream casing 20 is provided with the downstream collar 2.
0a, a downstream cover 20b whose diameter is larger than that of the downstream collar 20a, and a downstream taper 20c between the downstream collar 20a and the downstream cover 20b. The downstream side collar 20 a is fixed to the outer peripheral surface of the downstream side opening 12 c of the flexible pipe 12, and the downstream side cover 20 a
b is provided so as to cover the upstream cover 18b.
Further, when no external force is applied to the vibration absorbing device 10, the downstream side taper 20 c
b is away from the tip of b. Also, the downstream cover 2
A rim 20d that is substantially parallel to the upstream taper 18c is provided at the tip of the vibration absorber 10b.
In the state where no external force is applied, the upstream side taper 18c
In a state away from

Next, the operation of the vibration absorbing device 10 will be described with reference to FIGS. FIG. 2 is an explanatory diagram of an exhaust path of an engine to which the vibration absorbing device is applied. FIG.
As shown in the figure, the exhaust path 30 of the engine is composed of an exhaust manifold 32, a catalytic converter 33, a sub-muffler 34, and a main muffler 35 attached to the engine, and the respective devices are connected via a cover.
The exhaust path 30 of the engine vibrates between, for example, a specific deformation mode indicated by a dotted line in FIG. 2 when the vibration frequency of the engine reaches a certain frequency. Among these, the vibration absorbing device 10 of the present embodiment is installed at the locations (ie, antinodes) A and B where vibrations are greatest.

In the vibration absorbing device 10, the flexible pipe 12 has a hermetic property, and the large-diameter sleeve 14b of the inner pipe 14 is in close contact with the flexible pipe 12. Further, at the connection points A and B, the vibration absorbing device 10 is connected with good hermeticity. That is, in FIG.
An upstream exhaust pipe (not shown) is inserted so as to be inscribed in the large-diameter sleeve 14b, and a downstream exhaust pipe (not shown) is inserted so as to be inscribed in the downstream opening 12c of the flexible pipe 12. For this reason, in locations A and B of the engine exhaust path 30 that are connected by the vibration absorbing device 10, the exhaust gas flows from the upstream side to the downstream side without leaking to the outside.

The vibration absorbing device 10 installed as described above
In FIG. 1, when an extension force is applied, the upstream casing 18 and the downstream casing 20 are separated from each other, and the width of the mountain portion 12 a of the flexible pipe 12 (that is, the interval between the flexible pipes 12 in the axial direction) is increased. . Conversely, when a compressive force is applied, the upstream casing 18 and the downstream casing 20 approach each other, and the width of the peak portion 12a of the flexible pipe 12 decreases.

When the width of the peak portion 12a is increased or decreased as described above, energy consumption due to deformation of the peak portion 12a, energy consumption due to sliding between the spacer 16 and the flexible pipe 12, and energy consumption due to sliding between the spacer 16 and the inner pipe 14. Vibration is attenuated by energy consumption due to the sliding of. At this time, the contact area between the spacer 16 and the flexible pipe 12 is large because the spacer 16 is inserted into the ridge portion 12a of the flexible pipe 12 and is in contact with the inner wall thereof. Therefore, the spacer 16
The energy consumption due to the sliding between the flexible pipe 12 and the flexible pipe 12 is large, and the damping efficiency is also large.

When an unexpectedly large extension force is applied to the vibration absorbing device 10, the upstream casing 18
And the downstream casing 20 are separated from each other, but the upstream taper 18c of the upstream casing 18 and the downstream casing 2
After the collision with the rim 20d, the upstream taper 1
Since the rim 20c and the rim 20c are locked, the two casings 18, 20 do not separate further. On the other hand, when an unexpectedly large compression force is applied, the upstream casing 18 and the downstream casing 20 approach each other, but the tip of the upstream cover 18 b of the upstream casing 18 and the downstream side of the downstream casing 20. After the taper 20c abuts, the tip of the upstream cover 18b and the downstream taper 20c
c is locked, so that both casings 18, 2
Zero never approaches.

Also, when a bending force or a torsion force acts on the flexible pipe 12, the sliding area between the spacer 16 and the flexible pipe 12 is large, so that the energy consumption is large and the damping efficiency is large as described above. Become.
If an unexpectedly large bending force is applied,
The upstream casing 18 moves in the bending direction with respect to the downstream casing 20, but after any one of the two casings 18 comes into contact with each other, they are locked at each other. Does not move relative to the downstream casing 20 in the bending direction.

The vibration absorbing device 1 of the first embodiment described in detail above
According to 0, the following effects can be obtained. Since the contact area between the spacer 16 and the flexible pipe 12, that is, the sliding area, is large, the efficiency of damping vibration is high. Since the spacer 16 is inserted into the ridge portion 12a of the flexible pipe 12, it is not necessary to install the spacer 16 at a position different from the ridge portion 12a, and the entire length of the vibration absorbing device 10 is shortened accordingly. And can be designed in a compact shape.

The flexible pipe 12 has a mountain portion 12a.
Since only one is used, a more compact shape can be designed, and the structure is simple and can be manufactured at low cost. Since the vibration absorbing device 10 is attached to the antinode of the unique deformation mode in the exhaust path 30 of the engine, resonance can be suppressed to a small level. In this case, the mounting space is often narrow. However, even if the vibration absorbing device 10 is downsized, the damping efficiency is high, so that the vibration absorbing device 10 is suitable for mounting in such a mounting portion.

Since the casings 18 and 20 play a role in regulating the moving range in the expansion and contraction direction and the bending direction, there is no possibility that the flexible pipe 12 or the spacer 16 is damaged even when an irregularly large external force is applied. . [Second Embodiment] FIG. 3 is a cutaway view of a vibration absorbing device of the present embodiment.

The vibration absorbing device 50 of this embodiment includes a flexible pipe 52, an upstream inner pipe 54, a downstream inner pipe 55, a spacer 56, an upstream casing 58,
And a downstream casing 60. The flexible pipe 52 has only one peak portion 52a, and has the same configuration as the flexible pipe 12 of the first embodiment.

The upstream inner pipe 54 is a stepped pipe having a small-diameter sleeve 54a and a large-diameter sleeve 54b. The inner pipe of the first embodiment is provided except that a rim 54c is provided at an end of the small-diameter sleeve 54a. The configuration is the same as that of FIG. The downstream inner pipe 55 is fixed to the inner peripheral surface of the downstream opening 52 c of the flexible pipe 52. The end of the downstream inner pipe 55 provided with the rim 55c is disposed at a position exceeding the rim 54c of the upstream inner pipe and facing the rim 54c.

The spacer 56 is the spacer 1 of the first embodiment.
6 has the same configuration as that of FIG. The upstream casing 58 has an upstream collar 58a and an upstream cover 58b whose diameter is larger than that of the upstream collar 58a. The upstream collar 58a is fixed to the outer peripheral surface of the upstream opening 52b of the flexible pipe 52, and the upstream cover 58b is provided so as to partially cover the peak 52a of the flexible pipe 52.

The downstream casing 60 is provided with the downstream collar 6.
0a and a downstream cover 60b whose diameter is larger than that of the downstream collar 60a. The downstream collar 60a is fixed to the outer peripheral surface of the downstream opening 52c of the flexible pipe 52, and the downstream cover 60b faces the upstream cover 58b at a predetermined distance.

Next, the operation of the vibration absorbing device 50 will be described. The vibration absorbing device 50 is installed at the same location as the first embodiment (locations A and B in FIG. 2). When the vibration absorbing device 50 receives an extension force, the upstream casing 58 and the downstream casing 60 are separated from each other, and the width of the peak 52a of the flexible pipe 52 is increased. Conversely, when a compressive force is applied, the upstream casing 58 and the downstream casing 60 approach each other, and the width of the peak portion 52a of the flexible pipe 52 decreases. When the width of the peak portion 52a is increased or decreased in this manner, energy consumption due to deformation of the peak portion 52a, energy consumption due to sliding between the spacer 56 and the flexible pipe 52, and sliding between the spacer 56 and the inner pipe 54 The vibrations are damped by the energy consumption by.
At this time, as in the first embodiment, the energy consumption due to the sliding between the spacer 16 and the flexible pipe 12 is large, and the damping efficiency is also large.

If an unexpectedly large extension force is applied to the vibration absorbing device 50, the upstream casing 58
And the downstream casing 60 are separated from each other. After the rim 54c of the upstream inner pipe 54 and the rim 55c of the downstream inner pipe 55 collide, the rims 54c, 5c
5c is locked, so that both casings 58,
60 will not leave. On the other hand, when an unexpectedly large compression force is applied, the upstream casing 58 and the downstream casing 60 approach each other. After the front end of the upstream casing 58 and the front end of the downstream casing 60 abut against each other, the two casings 58 and 60 do not approach any further.

Also, when a bending force or a torsion force acts on the flexible pipe 52, the sliding area between the spacer 56 and the flexible pipe 52 is large, so that the energy consumption is large and the damping efficiency is large as described above. Become.
According to the vibration absorbing device 50 of the second embodiment described above, the same effects as those of the first embodiment can be obtained.

[Others] The embodiments of the present invention are not limited to the above-described embodiments, and it goes without saying that various embodiments can be adopted as long as they fall within the technical scope of the present invention. For example, in each of the above-described embodiments, the leading end of the internal space of the ridges 12a and 52a of the flexible pipes 12 and 52 is not filled with the spacers 16 and 56, but as shown in FIG. All spaces may be filled with spacers.

Although the flexible pipes 12 and 52 of each of the above embodiments have only one peak portion 12a or 52a, a plurality of flexible pipes may be provided. For example, FIG. 4 shows, as a modification of the first embodiment, an example in which two crests 12a are provided and a spacer 16 is inserted inside these. In this case, substantially the same effects as in the first embodiment can be obtained. However, the vibration absorber is advantageous in that it can be designed in a more compact shape as the number of peaks is smaller.

Further, in the first embodiment, a rim that is substantially parallel to the downstream taper 20c may be provided at the tip of the upstream cover 18b of the upstream casing 18. in this case,
The range of movement in the compression direction is determined by the rim and the downstream taper 20c.
Will be regulated by collision.

[Brief description of the drawings]

FIG. 1 is a cutaway view of a vibration absorbing device according to a first embodiment.

FIG. 2 is an explanatory diagram illustrating an exhaust path of an engine.

FIG. 3 is a cutaway view of a vibration absorbing device according to a second embodiment.

FIG. 4 is a sectional view of a modification of the first embodiment.

FIG. 5 is an explanatory diagram regarding a contact area between a spacer and a flexible pipe in a vibration absorbing mechanism.

FIG. 6 is a sectional view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Vibration absorber, 12 ... Flexible pipe, 12a ... Mountain part, 14 ... Inner pipe, 1
4a: small diameter sleeve, 14b: large diameter sleeve,
16 spacer, 18 upstream casing, 1
8a: Upstream collar, 18b: Upstream cover,
18c ... upstream taper, 20 ... downstream casing, 20a ... downstream collar, 20b ... downstream cover, 20c ... downstream taper, 20d ... rim,
30 ... exhaust path.

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 having one or a plurality of peaks; And a small-diameter sleeve disposed with a gap between the flexible pipe and the flexible pipe and the small-diameter sleeve. And a vibration absorbing spacer having a shape inserted into the vibration absorbing mechanism. 2. The vibration absorbing mechanism according to claim 1, wherein the vibration absorbing mechanism is mounted on an antinode of a unique deformation mode of the exhaust path of the engine in the middle of the exhaust path. Absorption mechanism. 3. The vibration absorbing mechanism according to claim 1, wherein the flexible pipe has only one crest. 4. The vibration absorbing mechanism according to claim 1, wherein the flexible pipe includes a regulating mechanism that regulates a moving range in an extending direction or a compressing direction. Absorption mechanism.