JP2000065265A - Flexible coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide simply and at a low cost a flexible coupling which regulates the displacement of the shearing and the twisting of a bellows, as well as follows to the displacement of the bending, compression and tension of the bellows freely. SOLUTION: As a regulating means 1 to regulate the movement of a bellows 2, an approximate linear movement mechanism is used. The linear movement position 6 in the approximate linear movement mechanism is engaged to one end side of the bellows 2, its other movement position is connected to the other end of the bellows 2, and the linear movement locus of the linear movement position 6 is made almost parallel to the axial center of the bellows 2. The linear movement position 6 is made almost coincide to the bending center of the bellows in the neutral condition of the bellows 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a flexible joint.

[0002]

2. Description of the Related Art Flexible joints using bellows are:
It is often used to absorb the relative displacement and vibration of a pipe connected to both ends of the joint, and is commonly used, for example, in an exhaust system of an automobile, especially in an FF vehicle with an engine sideways. In this case, it absorbs the vibration (relative displacement with the exhaust system downstream of the joint) caused by the engine swinging in the vehicle longitudinal direction, and absorbs the displacement in the pipe axis direction due to the thermal expansion of the exhaust pipe upstream of the joint. The main role of the joint is to carry out, but with the vibration, displacements in the shearing direction and the twisting direction also act on the bellows.

However, the bellows have a high degree of followability to the bending displacement of the bellows and the axial compression and tensile displacement due to its characteristics and have sufficient durability. However, the bellows cannot withstand the displacement in the twisting direction and the shearing direction. There is a problem that tracking is difficult and durability is extremely low.

[0004] Therefore, a structure that allows both bending, compression and tension displacement while restricting both shearing and twisting displacement of the bellows as described above is optimal, and realization of a joint having such a structure is a problem. It is.

In response to the above request, a flexible joint as shown in FIG. 7 has been proposed in FIG. 3 of Japanese Utility Model Application Laid-Open No. 2-99215. The joint structure shown in FIG. 7 has exhaust pipes 102 and 103 connected to both ends of a flexible pipe 101.
The brackets 104 and 105 are fixed to each other, the brackets 104 and 105 are extended toward the center of the flexible pipe 101, and the two arms 106 and 107 crossing between the brackets 104 and 105 are rotated in-plane. As much as possible, the flexible pipe 101 is restricted in shearing and twisting displacement.

FIG. 4 of the above publication proposes a flexible joint as shown in FIG. In the joint structure shown in FIG. 8, brackets 108, 103 are provided on exhaust pipes 102, 103 connected to both ends of a flexible pipe 101, respectively.
A bracket 109 is fixed, the brackets 108 and 109 are extended toward the center of the flexible pipe 101, and the two brackets 108 and 109 are connected by a single arm 110 so as to be rotatable in a plane, thereby restricting torsional deformation. are doing.

Further, as shown in FIG. 9, exhaust pipes 202 and 203 are connected to both ends of a flexible tube cover 201, and the exhaust pipes 202 and 203 are fitted together. The ball support grooves 204 and 205 in the axial direction are formed in the groove 203.
5, a ball 206 is fitted between the flexible tube covers 201 so as to absorb the bending (relative swing), compression and tension displacements while controlling the shearing and twisting of the flexible tube cover 201. No. 6,086,045.

[0008]

In the structure shown in FIG. 7, although the flexible pipe is allowed to bend slightly, the displacement of shear and torsion can be restricted, but cannot follow compression and tension. Therefore, the above-mentioned problem has not been solved.

In the structure shown in FIG. 8, the flexible pipe can follow the bending, compression and tension, but both of them involve an oblique shear displacement. is not.

Further, in the structure shown in FIG. 9, bending (relative swinging) and compression and tension displacements can be absorbed while restricting the shearing and twisting of the flexible tube cover 201. Malfunctions and abnormal noises in high-temperature gas atmospheres and reduced durability,
The exhaust pipe fitting portion is housed in the flexible tube cover to reduce the exhaust gas flow path and increase the resistance of the exhaust gas flow. There's a problem.

It is an object of the present invention to solve the above-mentioned problems with a simple and low-cost mechanism and to provide a highly durable and reliable flexible joint.

[0012]

According to a first aspect of the present invention, an approximate linear motion mechanism is used as a restricting means for restricting the movement of the bellows, and the mechanism is provided outside the bellows. It is characterized by being arranged in.

In the present invention, the bending and the axial expansion and contraction of the bellows are permitted by the approximate linear motion mechanism, and the shearing and twisting displacement of the bellows are regulated. In addition, since the approximate linear motion mechanism is disposed outside the bellows, the mechanism does not reduce the exhaust gas flow path, does not become a resistance of the flow of the fluid flowing through the bellows, and furthermore, the high-temperature fluid flows inside the bellows. Is not adversely affected by the high temperature atmosphere.

According to a second aspect of the present invention, in the first aspect, the linear motion portion of the approximate linear motion mechanism is engaged with one end of the bellows, and the other motion portion is connected to the other end of the bellows. The bellows is coupled to the end so that the linear motion locus of the linear motion portion is substantially parallel to the axis of the bellows.

In the present invention, since the linear trajectory of the linear motion portion is substantially parallel to the axis of the bellows, only the axial load is applied to the bellows during compression and tensile displacement of the bellows, and stress is applied to the bellows. Absent.

According to a third aspect of the present invention, in the second aspect, the linearly moving portion is substantially coincident with a bending center of the bellows in a neutral state of the bellows. .

According to the present invention, when the bellows is bent in the neutral state of the bellows, the linear motion portion is located on the linear locus and at the bending center of the bellows, so that no stress is applied to the bellows in the bending displacement of the bellows. .

According to a fourth aspect of the present invention, in the first, second or third aspect, the approximate linear motion mechanism is provided with a stopper means or a buffer means for restricting the movement of the mechanism. It is characterized by the following.

In the present invention, when the maximum allowable deformation load is applied to the bellows, the deformation of the approximate linear motion mechanism is limited by the stopper means or the buffer means, so that an excessive load is applied to the bellows and the mechanism. To prevent.

According to a fifth aspect of the present invention, the first to the fifth aspects are provided.
In the invention according to any one of the fourth to fourth aspects, the approximate movement mechanism is a watt-type mechanism. In the present invention, the effects of the first to fourth inventions can be exhibited.

According to a sixth aspect of the present invention, there is provided the sixth aspect of the invention.
In the invention according to any one of the fourth to fourth aspects, the approximate linear motion mechanism is a Scott-Russell type mechanism. In the present invention, the same action as in the first to fourth inventions is exerted, and the linear motion range of the linear motion portion can be extended as compared with the watt-type mechanism. Furthermore,
The approximate linear motion mechanism can be arranged only on one side in the radial direction of the bellows.

According to a seventh aspect of the present invention, there is provided the seventh aspect of the invention.
In the invention according to any one of the fourth to fourth aspects, the approximate linear motion mechanism is a grasshopper type mechanism. In the present invention, the same action as in the first to fourth inventions is exhibited, and the linear motion range is extended by making a part of the link of the mechanism sufficiently long. Therefore, if space is allowed in the axial direction of the bellows, the linear motion range can be made longer than that of the Watt-type mechanism or Scott-Russell mechanism to accommodate a bellows having a large expansion and contraction length. Furthermore,
The approximate linear motion mechanism can be arranged only on one side in the radial direction of the bellows.

According to an eighth aspect of the present invention, the approximate linear motion mechanism is a Chebyshev type mechanism.
In the present invention, the same functions as those of the first to fourth inventions are exhibited, and the approximate linear motion mechanism can be arranged on only one side in the radial direction of the bellows.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described based on an embodiment shown in FIGS. FIG. 1 shows a first embodiment.

In FIG. 1, one pipe, for example, an upstream pipe 3 in an exhaust system of an internal combustion engine is airtightly fitted to one end of a bellows 2 whose movement is regulated by a regulating means 1 and fixed by welding or the like. The other end of the bellows 2 is hermetically fitted with the other pipe, for example, a downstream pipe 4 in an exhaust system, and is fixed by welding or the like.

The regulating means 1 of this embodiment will be described in detail.
One end of a bracket 5 is fixed to the outer surface of the one pipe 3 by welding W, and the other end of the bracket 5 extends outside the bellows 2 to approximately the center of the bellows 2 in the axial direction. A bellows 2 is attached to the extension end of the bracket 5.
A pivot 6 is provided at a substantially central portion in the axial direction of
A first link 7 is rotatably mounted at an intermediate portion of the first link 7 via the pivot 6. A second link 8 is rotatably mounted on one end of the first link 7 by a pin 9.
Further, the third link 10 is provided with a pin 1 at the other end of the first link 7.
1 so as to be rotatably mounted on the shaft.

An arm 12 is provided on the outer surface of the other pipe 4.
Is fixed by welding W, and one end of one of the arms 12 is bent at both ends toward the bellows 2 and along the axial direction.
a and the other arm portion 12b are integrally formed.

The other end of the second link 8 is pivotally attached to the tip of the one arm 12a by a pivot 13. The third link 8 is attached to the tip of the other arm 12b. The other end of the link 10 is rotatably mounted on a pivot 14.

Here, the distance from the pivot 6 to the pin 11 is A, and the distance from the pivot 6 to the pin 9 is B
If the distance from the pin 9 to the pivot 13 is C and the distance from the pin 11 to the pivot 14 is D, A:
B = C: D is set.

The pins 9 and 11 are well-known shafting techniques such as a dove-eye structure, a bolt and nut structure, and a rivet structure, and can pivotally support both shaft-mounted links so as to be relatively rotatable. I just need.

Further, the pivotal connection between the bracket 5 and the first link 7, the pivotal connection between the arm 12 and the second link 8, and the pivotal connection between the arm 12 and the third link 105 are made by the non-rotatable bracket 5
And a pivot structure for pivotally attaching links 7, 8, and 10 to the arm 12. This pivot 6,1
Reference numerals 3 and 14 are of a well-known technology, and are rotatably supported only in one plane, similarly to the pins.

It is sufficient that the relative rotation of the shaft mounting member is satisfied in each of the shaft mounting portions, and the pins 9 and 11 may be pivots, or the pivots 6, 13 and 14 may be pins. In both cases, a bearing having a small rotational resistance may be used, and it is more preferable to use a material having self-lubricating properties.

In this structure, a second link 8 and a third link 10 are rotatably mounted on both ends of the first link 7 and the second link 8 and the third link 10 are connected to the other ends (the pivots 13 and By oscillating with 14) as the fulcrum, the first
Pivot 6 parts of the link 7 partially depicts a 8-shape shown by a chain line R ₁ in FIG. 1 constitutes an approximate straight line portion R _2, and the so-called Watts splines linear movement mechanism (Watts type mechanism).

Therefore, the pivot 6 becomes a linear motion portion in the range of the approximate linear portion R _{2. By} pivotally attaching the pivot 6 to the bracket 5, the one pipe 3 is connected to the approximate linear portion R _2. , That is, along the axial direction of one pipe 3 (the axial direction of the bellows 2).

In addition, the pivot 6 which is the above-mentioned linear motion portion
Is set to be parallel to the axis of the bellows 2, and the pivot 6 is set to substantially coincide with the center of bending of the bellows 2 in the neutral state of the bellows 2.

With the above construction, when rotational forces are applied to the two pipes 3 and 4 in opposite directions about their axes, the bracket 5 is fixed to one pipe 3 and the arm 12 is The rotation of the two pipes 3, 4 is restricted by the shaft attachment mechanism which is fixed to the other pipe 4 and in which the links 7, 8, 10 are allowed to rotate only in one plane as described above, and the bellows. No. 2 does not receive torsional stress. Further, this mechanism allows the two pipes 3 and 4 to move only in the direction of the paper surface of FIG. 1, and restricts the movement of the front and back surfaces of the paper surface.

When one of the pipes 3 and the other pipe 4 is subjected to a compressive and tensile force that causes relative movement in the axial direction (the direction indicated by the arrow X in FIG. 1), the pivot 6 causes the bellows 2 and both pipes to move. It moves only in the direction coinciding with the axis of the pipes 3 and 4. Therefore, the bellows 2 expands and contracts along its axis, and no stress is applied to the bellows 2.

When the pipes 3 and 4 rotate relatively in opposite directions about the bellows 2 (the direction of the arrow Y in the direction of the paper of FIG. 1), that is, when bending stress acts on the bellows 2 , Bracket 5, arm 12, and each link 7,
The bellows 2 bends while the pivot 6 is stopped at the fixed position (bellows bending center) by the cooperation of 8, 10. Therefore, no stress is applied to the bellows 2 in this case as well.

Further, the two pipes 3 and 4 are moved parallel to each other in a direction perpendicular to the axis of the pipe and relatively in the opposite direction (the direction of arrow Z in the direction of the paper of FIG. 1), that is, bellows. When a shearing force acts on the pivot 2, the pivot 9, the arm 12, and the links 7, 8, 10 cooperate with each other.
Stays at the fixed position (bellows bending center),
The two pipes 3 and 4 are not allowed to move in parallel. Therefore,
Bellows 2 is not stressed.

From the above, the bellows 2 can freely follow the bending, compression and tension without stress,
A flexible joint in which shear and torsion stress is not applied to the bellows 2 is realized.

Since the members constituting the above-described watt-type approximate linear motion mechanism are provided outside the bellows 2 and both pipes 3 and 4, the members are arranged in the bellows 2 and both pipes 3 and 4. Since the path is not narrowed and the resistance of the fluid flowing through the bellows and the pipes 3 and 4 is not reduced, and the high-temperature exhaust gas is not adversely affected by the high-temperature atmosphere. High reliability and durability can be obtained.

Although the bellows 2 may be used alone,
The outer periphery of the bellows 2 may be covered with a blader, a blader or an interlock tube may be fitted inside the bellows 2, and the combination thereof is optional.

Further, since this flexible joint allows bending only in one plane (the direction of the paper in the drawing), the flexible joint is provided in conformity with a required bending plane.
Further, the length of the approximate straight line portion R _2, it is desirable to set sufficiently longer than the maximum displacement length of time compression and tension of the bellows. FIG. 2 shows a second embodiment.

In the second embodiment, as shown in FIG. 2A, the bellows 22 whose movement is regulated by the regulating means 21
Is fixed to one end thereof, and the other end of the other pipe 24 is fixed thereto.

The regulating means 21 of the second embodiment will be described in detail. An inverted L-shaped arm 25 is fixed to one pipe 23 by welding W, and a bracket 26 is fixed to the other pipe 24 by welding W. A pivot 27 is provided on the bellows-side extending portion of the arm 25, and a pivot 28 is provided on the bellows-side extending portion of the bracket 26 so as to be located on one straight line in the axial direction of the bellows 22. A slot-like guide groove 29 toward the pivot 27 is formed at a lower portion of the arm 25, and a pin 30 is formed in the guide groove 29.
Are slidably disposed.

A first link 31 is rotatably disposed between the pivot 28 and the pin 30.
A pin 32 is provided at an intermediate portion of the first member 1, and a second link 33 is rotatably disposed between the pin 32 and the pivot 27. The distance between the pivot 28 and the pin 32 and the distance between the pin 3
The distance between 0 and 32 and the distance between pivot 27 and pin 32 are set substantially equal. In addition, the pin 30 is provided with a roller 34 in the guide groove 29 so as to roll freely, as shown in FIG. 2B, in order to smoothly slide with the arm 25 and rotate with the first link 31. The pin 30 is inserted through the roller 34, and the first link 31 is loosely fitted to the pin 30.

Note that the pivot 2 in the second embodiment is
The shaft attachment portions of the pins 7 and 28 and the pins 30 and 32 may have other structures as in the first embodiment. In this configuration, the first pin 30 is moved along the guide groove 29 so that the first
The link 31 and the second link 33 open and close, and the pivot 2
7 and 28 linearly move along a straight line R ₃ orthogonal to the straight line connecting the pivot 27 and the pin 30, and constitute a so-called Scott-Russell-type approximate linear movement mechanism (Scott-Russell-type mechanism).

Therefore, also in the present embodiment, the relative movement of the two pipes 23 and 24 in the Z direction is restricted, and the compression and the tension (the relative movement in the X direction) in the paper direction of FIG. On the other hand, the bellows 22 freely follows without any stress, and further, the bellows 22 freely follows any bending (relative movement in the Y direction) without any stress. Therefore, similarly to the first embodiment, a flexible joint in which shear and torsion stresses are not applied to the bellows 22 can be realized, and the same effects as in the first embodiment can be exhibited.

The second embodiment is characterized in that the trajectory of the linear motion is longer than that of the watt-type approximate linear motion mechanism of the first embodiment. Therefore, the second embodiment is effective when the expansion and contraction stroke of the bellows 22 is long. . Further, in the first embodiment, the links are on both sides of the bellows 2 (vertical direction in the figure).
However, in the second embodiment, the link is arranged only on one side (the lower side in the figure) of the bellows 22, and the mechanism is compact.

FIG. 3 shows a third embodiment. In the third embodiment, the bellows 42 whose movement is restricted by the restricting means 41
One of the pipes 43 is fixed to one end, and the other pipe 44 is fixed to the other end.

The regulating means 41 of the third embodiment will be described in detail. An arm 45 is fixed to one pipe 43 by welding W, and a bracket 46 is fixed to the other pipe 44 by welding W. A pivot 47 is provided on the bellows-side extension of the arm 45, and a pivot 48 is provided on the bellows-side extension of the bracket 46 so as to be located on one straight line in the axial direction of the bellows 42. A first link 50 is pivotally attached to the other end of the arm 45 by a pivot 49, and a second link 52 is pivotally attached to the other end of the first link 50 by a pin 51. The second link 5
The other end of 2 is pivotally attached to the bracket 46 by the pivot 48, and a third link 54 is pivotally attached by a pin 53 substantially at the center of the second link 52,
The other end of the third link 54 is pivotally attached to the arm 45 by the pivot 47. The distance between the pin 51 and the pin 53, the distance between the pivot 48 and the pin 53, and the distance between the pivot 47 and the pin 53 are set substantially equal.

Note that the pivot 4 in the third embodiment is used.
7, 48, 49 and the pin attachment portions of the pins 51, 53 are also the first
Other structures may be used as in the embodiment. This configuration,
In the Scott-Russell-type approximate linear motion mechanism shown in FIG. 2, the slide mechanism by the guide groove 29 and the pin 30 is pseudo-replaced by a swinging first link 50.
The swing of the first link 50 about the pivot 49 opens and closes the second link 52 and the third link 54, and the pivots 47 and 48 are connected to a straight line R connecting the pivots 47 and 48.
It moves in _four directions to form a so-called grasshopper type approximate linear motion mechanism (grasshopper type mechanism).

Therefore, also in the present embodiment, the relative movement of the two pipes 43 and 44 in the Z direction is restricted.
Bellows 42 freely follow stress and compression (relative movement in the X direction) in the paper surface direction, and further follow bellows 42 freely without stress in bending (relative movement in the Y direction). I do. Therefore, similarly to the first embodiment, the shear and torsion stresses are reduced by the bellows 4.
2 can be realized, and the same effects as in the first embodiment can be exhibited.

In the third embodiment, if the first link 50 is made sufficiently long, the linear motion range can be extended, and this is effective when the expansion and contraction stroke of the bellows 42 is long. Further, there is a feature that the configuration is simplified as compared with the second embodiment. Further, similarly to the second embodiment, the link can be compactly arranged on only one side of the bellows.

FIG. 4 shows a fourth embodiment. In the fourth embodiment, the bellows 62 whose movement is regulated by the regulating means 61
Is fixed to one end, and the other pipe 64 is fixed to the other end.

The regulating means 61 of this embodiment will be described in detail. A bracket 65 is fixed to one pipe 63 by welding W, and an arm 66 is fixed to the other pipe 64 by welding W. A pivot 67 is provided at the bellows-side extension of the bracket 65 at a position substantially at the center of the bellows 62 in the axial direction, and the first link 6 is provided by the pivot 67.
8 is rotatably mounted at the center thereof, a second link 70 is mounted on one end of the first link 68 by a pin 69, and a third link 72 is mounted on the other end by a pin 71. I have. The second link 70 and the third link 72 intersect with each other, and the other end is pivotally attached to the arm 66 by pivots 73 and 74.

The distance between the pin 71 and the pivot 74 and the distance between the pivots 73 and 74 are set equal.
The distance between the pins 69 and 71 is the distance between the pin 71 and the pivot 7.
The distance between the pivots 73 and 74 is set to half of the distance between the pin 71 and the pivot 74.
It is set to 83 times.

Note that the pivot 6 in the fourth embodiment is used.
7, 73 and 74 and the pin attachment portions of the pins 69 and 71 are also the same as those of the first embodiment.
Other structures may be used as in the embodiment. This configuration,
The second link 70 and the third link 72 are pivots 73, 74
By pivoting the pivot 67 around the fulcrum, the pivot 67
Draw a locus of a chain line R _5, its part having a straight portion R ₆ to constitute a so-called Chebyshev second approximate straight line motion mechanism (Chebyshev type mechanism).

Therefore, also in this embodiment, the relative movement of the two pipes 63 and 64 in the Z direction is restricted, and the bellows are compressed and pulled in the direction of the paper surface of FIG. The bellows 62 freely follows without stress, and the bellows 62 freely follows with respect to bending (relative movement in the Y direction) without stress. Therefore, as in the first embodiment, the shearing and torsional stresses are reduced by the bellows 6.
2 can be realized, and the same effects as in the first embodiment can be exhibited.

Also in the fourth embodiment, the mechanism can be compactly arranged on one side of the bellows 62. Although the above-described embodiment is an example using a representative one of the approximate linear motion mechanisms, it may be arranged as in the above-described embodiment using an approximate linear motion mechanism other than this embodiment. Is not limited to the mechanism of the above embodiment.

FIG. 5 shows a fifth embodiment. In the fifth embodiment, the movement of the two bellows in parallel is regulated by this one mechanism by using the regulating means 1 comprising the watt type approximate linear movement mechanism of the first embodiment.

That is, one pipe 80 and the other pipe 81 are connected by a first bellows 82, and the other one pipe 83 and the other pipe 84 are connected by a second bellows 85, and one pipe is connected. Bracket 86 is connected to both pipes 80, 8
3 and one arm 87 is fixed to the pipes 81 and 84 by welding W, and the bracket 86 extends to the middle between the bellows 82 and 85. A pivot 88, which corresponds to the pivot 6 of the first embodiment, is provided at the distal end thereof at a substantially central portion in the axial direction of the bellows 82, 85. Further, in the arm 87,
Pivots 89 and 90 corresponding to the pivots 13 and 14 of the first embodiment are provided, and a first link 91 corresponding to the first link 7 of the first embodiment is rotatably mounted on the pivot 88; Pins 92 and 93 are provided at both ends of the first link 91. A second link 94 corresponding to the second link 8 of the first embodiment is rotatably mounted on the shaft between the pivot 89 and the pin 92, and the second link 94 is provided between the pivot 90 and the pin 93 in the first embodiment. A third link 95 corresponding to the third link 10 is rotatably mounted on the shaft.

With such a configuration, both bellows 82 and 85 are moved by the relative movement of the pipe in the compression and pulling directions.
Pivot 88 disposed in the middle of the center of bending of the bellows moves linearly in the axial direction of both bellows 82 and 85. Therefore, in a parallel pipe, for example, in a dual exhaust pipe of an internal combustion engine, the parallel bellows are connected by one linear motion mechanism.
The same effects as in the first embodiment can be exhibited while maintaining the parallelism.

In the fifth embodiment, the mechanism is arranged in parallel with the plane of the paper so that the bellows can be bent in a direction parallel to the plane of the paper. However, when the bellows is adapted to bend in the direction perpendicular to the plane of the paper, A mechanism may be arranged between the two bellows 82 and 85 in a direction perpendicular to the paper surface.

For such parallel bellows, the mechanisms of the second, third, and fourth embodiments may be used, and other approximate linear motion mechanisms may be used.
FIG. 6 shows a means for limiting, for example, the amount of compression or tension of the bellows in each of the above embodiments.

That is, the stopper means 9 in which one of the two links 96, 97 corresponding to the shaft-mounted link in each of the above-mentioned embodiments comes into contact with the other link 97.
8a is provided to limit the closing angle between the two links 96 and 97 so that an excessive load is not applied to the bellows and the mechanism, thereby preventing the bellows and the mechanism from being damaged.

For example, the arm 12 in FIG. 1 is used as one link 96 and the third link 10 is used as the other link 9.
7, the stopper means 98a is provided on the arm 12 side.
Is provided, the closing angle between the third link 10 and the arm 12 can be regulated, and the reduction amount of the bellows 2 can be regulated.

As the stopper means 98a, FIG.
As shown in (a), a part of one link 96 may be formed by bending so that the other link 97 is locked.
Further, as shown in FIG. 6B, a part of one link 96 may be formed by a bulged portion 98b cut and raised so that the other link 97 is locked. As shown in (), stoppers 98c and 98d protruding so as to be opposed to the links 96 and 97 are provided, and buffering means 58e such as a wire mesh is provided on one of the stoppers. Good. Further, the movement may be limited only by the buffer means instead of the stopper means.

The approximate linear motion mechanism in each of the above embodiments has its bracket and arm fixed to the pipe side and indirectly provided on the bellows. However, the bracket and arm are fixed to the end of the bellows. It may be provided directly on the bellows.

The present invention is not limited to the case where the exhaust pipe of an automobile is connected to a flexible pipe such as a bellows or the like, but may be applied to other flexible couplings in an automobile, and furthermore, to any plant or equipment other than an automobile. It can also be applied to flexible joints such as piping.

Further, the link may be a flat plate, a hollow member or a solid member having an arbitrary cross section, and may be bent if the link ratio is under the condition.

[0072]

As described above, according to the first aspect of the present invention, the bellows can freely follow the bending, compression and tension displacements while restricting the shearing and twisting displacements of the bellows. A flexible joint can be realized only by adding a simple and low-cost mechanism.

Further, since this mechanism is disposed outside the bellows, the flow passage in the bellows is not narrowed and the resistance of the fluid flowing in the bellows is not reduced. Further, in the case where high-temperature exhaust gas flows through the bellows, the mechanism is not adversely affected by the high-temperature atmosphere, so that high reliability and durability can be obtained.

Further, since the shearing and the torsional displacement are completely regulated, the life of the bellows itself is extended, and if the life is the same, the bellows can be further thinned, and the weight and the flexibility can be reduced.

According to the second aspect of the present invention, no stress is applied to the bellows when the bellows is compressed or pulled, so that the life of the bellows can be further extended.

According to the third aspect of the present invention, no stress is applied to the bellows in bending displacement of the bellows,
Further, the life of the bellows can be further extended. According to the fourth aspect of the present invention, it is possible to prevent the bellows and the mechanism from being damaged due to an excessive load acting on the bellows and the mechanism.

According to the fifth aspect of the present invention, the above effects can be achieved with a simple mechanism. According to the inventions of claims 6 and 7, in addition to the above-mentioned effects, there is an effect that the linear motion range can be extended with a simple structure as compared with the mechanism of claim 5. Further, there is an effect that the mechanism can be compactly arranged only on one side in the radial direction of the bellows.

According to the eighth aspect of the present invention, in addition to the same effects as those of the first to fourth aspects, there is an effect that the mechanism can be compactly disposed only on one side of the bellows in the radial direction.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a side view showing a second embodiment of the present invention.

FIG. 3 is a side view showing a third embodiment of the present invention.

FIG. 4 is a side view showing a fourth embodiment of the present invention.

FIG. 5 is a side view showing a fifth embodiment of the present invention.

FIGS. 6A and 6B show a means for restricting the movement of the mechanism in the present invention, wherein FIG. 6A shows a bent stopper, FIG. 6B shows a bulged stopper, and FIG. And a combination of the stopper and the buffer means.

FIG. 7 is a perspective view showing a first conventional technique.

FIG. 8 is a side view showing a second conventional technique.

FIG. 9 is a side sectional view showing a third conventional technique.

[Explanation of symbols]

1,21,41,61 Approximate linear motion mechanism as a regulating means 2,22,42,62,82 Bellows 6,27,28,47,48,67,88 Linear motion locations 98a, 98b, 98c, 98d: stopper means 98e: buffer means

Claims (8)

[Claims] 1. A flexible joint wherein an approximate linear motion mechanism is used as a restricting means for restricting the movement of the bellows, and the mechanism is disposed outside the bellows. 2. A linear motion portion of the approximate linear motion mechanism is engaged with one end of the bellows, and another motion portion is coupled to the other end of the bellows. 2. The flexible joint according to claim 1, wherein the flexible joint is substantially parallel to an axis of the flexible joint. 3. The flexible joint according to claim 2, wherein the linear motion portion substantially coincides with a center of bending of the bellows in a neutral state of the bellows. 4. The flexible joint according to claim 1, wherein the approximate linear motion mechanism is provided with a stopper means or a buffer means for restricting the movement of the mechanism. 5. The flexible joint according to claim 1, wherein the approximate linear motion mechanism is a watt type mechanism. 6. The flexible joint according to claim 1, wherein the approximate linear motion mechanism is a Scott-Russell type mechanism. 7. The flexible joint according to claim 1, wherein the approximate linear motion mechanism is a grasshopper type mechanism. 8. The flexible joint according to claim 1, wherein the approximate linear motion mechanism is a Chebyshev type mechanism.