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Title:
DEVICE FOR DIRECTING EXHAUST GASES IN AN ARTICULATED VEHICLE
Document Type and Number:
WIPO Patent Application WO/2015/152791
Kind Code:
A1
Abstract:
The present invention relates to a flexible device (102) for directing exhaust gases from a first vehicle body to a second vehicle body of an articulated vehicle, wherein the exhaust gases are used for heating the second vehicle body. The flexible device (102) comprising: a first tube being a heat resistant flexible tube, the first tube (408) being contained by a helical extension spring (402) and fixed to the helical extension spring (402), the helical extension spring (402) being fixed to the first tube (408) such that the flexible device (102) having a loaded and an unloaded condition, wherein a length of the flexible device (102) in the loaded condition is at least 50% larger compared to the length of the flexible device in the unloaded condition.

Inventors:
SAMUELSON CARL (SE)
YORULMAZ HAKAN (FR)
Application Number:
SE2015/050335
Publication Date:
October 08, 2015
Filing Date:
March 20, 2015
Export Citation:
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Assignee:
TRELLEBORG IND AB (SE)
International Classes:
F01N13/08; B60K13/04; F16L11/118; F16L11/12
Foreign References:
US20080093151A12008-04-24
DE4426722C11995-11-02
DE3505699C11986-08-14
EP1463650B12009-03-18
Attorney, Agent or Firm:
AWAPATENT AB (Box 5117, Malmö, SE)
Download PDF:
Claims:
CLAIMS

1 . A flexible device (102) for directing exhaust gases from a first vehicle body (104) to a second vehicle body (106) of an articulated vehicle (100), the flexible device (102) being connected to a first exhaust pipe (108) fixed to the first vehicle body (104) via a first connection means (202a) and to a second exhaust pipe (1 10) fixed to the second vehicle body (106) via a second connection means (202b), the flexible device (102) comprising:

a first tube (408) being a heat resistant flexible tube,

the first tube (408) being contained by a helical extension spring (402) and fixed to the helical extension spring (402),

the helical extension spring (402) being fixed to the first tube (408) such that the flexible device (102) having a loaded and an unloaded condition,

wherein a length of the flexible device (102) in the loaded condition is at least 50% larger compared to the length of the flexible device in the unloaded condition.

2. The flexible device according to claim 1 , wherein the length of the flexible device (102) in the loaded condition is at least 65% larger compared to the length of the flexible device (102) in the unloaded condition.

3. The flexible device according to any one of claims 1 -2, wherein a distance between the first (108) and second (1 10) exhaust pipe when the articulated vehicle (100) is in a fully pivoted state is less than 90% of the max length of the first tube (408) when being in a fully extended state.

4. The flexible device according to any one of claims 1 -3, wherein the flexible device (102) is adapted for enduring temperatures up to 580°C without substantial deformation.

5. The flexible device according to any of claims 1 -4, wherein the flexible device (102) further comprises a second tube (404) being a heat resistant flexible tube enclosing the helical extension spring (402) and the first tube (408).

6. The flexible device according to claim 5, wherein the second tube (404) is fixed to the flexible device (102) by hose clamps (418) fixed to the first

(202a) and second (202b) connection means.

7. The flexible device according to any of claims 1 -6, wherein the helical extension spring (402) is fixed to the first tube (408) by means of a strip (406) of a heat resistant material, and wherein the strip (406) is fixed to the first tube (408) over at least a part of the coils of the helical extension spring (402).

8. The flexible device according to claim 7, wherein the strip (406) is fixed to the first tube (408) by means of stitches of a thread made of heat resistant fibers.

9. The flexible device according to any one of claims 7-8, wherein at least some of the coils of the helical extension spring (402) are fully enclosed by the strip (406) of heat resistant material and the first tube (408).

10. The flexible device according to any one of claims 7-9, wherein the ends of the helical extension spring (402) are fixed to the first (202a) and second (202b) connection means.

1 1 . The flexible device according to any one of claims 1 -10, wherein the first (202a) and second (202b) connection means each comprises an inner metal pipe (424) and an outer metal pipe (422), wherein a first end and a second end of the first tube (408) is fixed to the first (202a) and second connection means (202b) respectively by positioning each end of the first tube (408) between the inner (424) and the outer (422) metal pipe of the corresponding connection means (202a, 202b) and mechanically pressing the inner (424) and outer (422) metal pipe together.

12. The flexible device according to claim 1 1 , wherein an outlet of the inner metal pipe (424) for outflow of the exhaust gas from the first connection means (202a) is formed by a end portion (614) of the inner metal pipe (424), the end portion (614) being tapered in a flow direction of the exhaust gas.

13. The flexible device according to any one of claims 1 1 -12, wherein an inlet of the inner metal pipe (424) for inflow of the exhaust gas into the second connection means (202b) is formed by an end portion (614) of the inner metal pipe (424), the end portion (614) being widened in a flow direction of the exhaust gas.

14. An articulated vehicle (100) comprising

a first vehicle body (104),

a second vehicle body (106),

a first exhaust pipe (108) fixed to the first vehicle body (104), a second exhaust pipe (1 10) fixed to the second vehicle body (106), and

a flexible device (102) according to any one of claim 1 -13 for directing exhaust gases from the first vehicle body (104) to the second vehicle body (106) via the first exhaust pipe (108) and the second exhaust pipe (1 10).

Description:
DEVICE FOR DIRECTING EXHAUST GASES IN AN ARTICULATED

VEHICLE

Technical field of the invention

The present invention relates to a flexible device for directing exhaust gases from a first vehicle body to a second vehicle body of an articulated vehicle, wherein the exhaust gases are used for heating the second vehicle body.

Background of the invention

A articulated vehicle, for example a trailer or a hauler, may comprise a first vechicle body wherein an engine is located and a second vehicle body comprising a bucket for holding material to be transported, e.g. stones, sand or similar, by the articulated vehicle. This type of articulated vehicle is capable of unloading or ejecting the material from the second vehicle body at various times. However, in certain weather conditions, the material has a tendency to adhere to the bucket of the second vehicle body thereby resisting ejection from the articulated vehicle.

For this reason, it has for many years been common to transfer exhaust gases, by use of a conduit, from the first vehicle body to the second vehicle body in order to heat various portions of the bucket of the second vehicle body. This heat inhibits the tendency of the material to stick to the bucket walls.

However, an articulated vechicle is typically designed to be steered by bending the vehicle in the middle around the hitch assembly. Thus, the conduit which is used to convey the flow of exhaust from the motor of the first vechicle body to the second vehicle body must be able to accommodate changes in the distance and angular relationship between the first vehicle body and the second vehicle body during operation of the articulated vehicle. In particular, the hitch assembly allows the first vehicle body to be pivoted in relation to the second vehicle body in a horizontal plane (e. g. during a left or right turn). Moreover, the hitch assembly of the articulated vechicle typically allows the first vehicle body to be moved in a rotational direction relative to the second vehicle body due to the very coarse terrain in which the articulated vehicle is typically employed (e. g. due to scattered rocks or holes in the field). US 2008/0093151 (Komatsu LTD.) allegedly solves this problem using a exhaust pipe device interconnecting the first and the second vehicle bodies so that oscillation and swing of the first or the second vehicle body relative to each other can be allowed. The exhaust pipe device comprises a plurality of pipes, a hose and rotatable connections to allow for absorbing the oscillation and swing of the first and second vehicle body. A problem with this approach is that, since the exhaust gases are hot and are flowing through the exhaust pipe device in high speed, soot particles may clog the inside of the exhaust gas device and start to burn. This is particularly a problem where the pipes/hoses are interconnected with each other. When being clogged by the soot particles, the flexibility and ability of the exhaust pipe system to allow for oscillation and swing is severely decreased. Moreover, the exhaust pipe device in US 2008/0093151 is complex and expensive to manufacture and install.

EP 1463650 (Umiastowski) discloses a device for guiding exhaust gases from a vehicle, i.e. a car, such that the gases are not accumulated in a trailer towed by the vehicle. The device may comprise a flexible tube comprising an outer metal coil which contains a tube formed from one or more heat resistant textile layers. The trailer is typically a caravan for people or horses. Indeed, this device is designed to be used on straight roads, under calm conditions. Moreover, there is no need for the exhaust gases to be kept hot, since the gases are not used for heating up the trailer. The device may for example comprise cooling fins to cool the exhaust gases guided by the device. Moreover, exhaust gases from a car differs from exhaust gases from a larger diesel motor as often used in the above mentioned articulated vehicle when it comes to speed of the gases and heat of the gases.

Summary of the invention

In view of the above, an objective of the invention is to solve or at least reduce one or several of the drawbacks discussed above. Generally, the above objective is achieved by the attached independent patent claims.

According to a first aspect, the present invention is realized by a flexible device for directing exhaust gases from a first vehicle body to a second vehicle body of an articulated vehicle, the flexible device being connected to a first exhaust pipe fixed to the first vehicle body via a first connection means and to a second exhaust pipe fixed to the second vehicle body via a second connection means, the flexible device comprising: a first tube being a heat resistant flexible tube, the first tube being contained by a helical extension spring and fixed to the helical extension spring, the helical extension spring being fixed to the first tube such that the flexible device having a loaded and an unloaded mode, wherein a length of the flexible device in the loaded condition is at least 50% larger compared to the length of the flexible device in the unloaded condition.

The present invention is based on the understanding that by using a first tube for directing exhaust gases from a first vehicle body to a second vehicle body for heating parts of the second vehicle body, an increased flow of exhaust gases may be achieved. This may be advantageous since reduction of flow decreases the efficiency of the heating system of the second vehicle body. Moreover, by allowing for increased flow, the risk of pressure being built up in the exhaust system may be decreased. Such a pressure can have a negative effect of the engine performance of the articulated vehicle and can further increase the risk of engine failure.

Moreover, the inventors have realized that using a corrugated, i.e. extendable and compressible, tube alone may mean that the compression and extension of the flexible device for directing exhaust gases cannot be controlled to the extent that may be necessary for the harsh condition in which the flexible device is employed. The solution for this problem may be to let the first tube being contained by a helical extension spring and fixed to the helical extension spring such that the flexible device has a loaded and an unloaded mode. By fixing the first tube to the helical extension spring such that when the spring is in an unloaded mode, the first tube is compressed within the spring, the flexible device may be compressed in a controlled way. When the distance between the first and second vehicle body is increased, e.g. due to changed angular relationship between the first vehicle body and the second vehicle body, the helical extension spring is extended, which means that the first tube is also extended. When the distance is decreased, the deflection force of the extension spring, i.e. when the load of the spring is decreased, will cause the entire flexible device to be compressed in a controlled way.

By allowing the length of the flexible device in the loaded condition to be least 50% larger compared to the length of the flexible device in the unloaded condition, the articulated vehicle may be constructed such that it allows for large variations of the distance between the first and the second exhaust pipe when employing the vehicle. This may for example allow for an increased pivot between the first and second vehicle body, and consequently to a more easy to drive vehicle. It may further allow for the vehicle to be driven in a very coarse terrain with sudden differences in height. Further, since the first tube can be compressed to such an extent and still be controlled and contained by the helical extension spring this may allow for reduced minimum distance between first vehicle body and second vehicle body. This may further have the advantage that the installation of the flexible device between the first vehicle body and the second vehicle body can be done on a smaller area and that such an installation may be simplified.

Moreover, the design of the flexible device may allow for the first vehicle body to be moved in a rotational direction relative to the second vehicle body without any further swiveling features such that rotatable connection means connecting the flexible device to the first and second exhaust pipes of the first and second vehicle body. Both the helical extension spring and the first tube can, without breaking or being deformed, withstand the torsional movement arising when being employed in an articulated vehicle when the vehicle used in a coarse terrain. This may further simplify the manufacturing and the installation process of the flexible device since no swiveling connection means may be needed. A fixed connection means may further be cheaper and more durable than a swiveling connection means.

A further advantage of the inventive flexible device is that is comprises less components compared to prior art since the extension/compression and the rotation is handled by the first tube in combination with the helical extension spring. This may have the advantage that the flexible device has a reduced price and can be manufactured in a simple way.

Moreover, by using a tube which is contained in a helical extension spring for directing the exhaust gases, the risk of clogging the flexible device with soot articles is reduced since the number of edges inside the flexible device were soot particles can get stuck is reduced. Further, since the shape of the flexible device will be more or less straight or at least without any abrupt bends, no matter if the flexible device is in a loaded or unloaded condition, the risk of clogging the device may be reduced. This may increase the lifetime of the flexible device.

A further advantage of having such a flexible device for directing exhaust gases from a first vehicle body to a second vehicle body of an articulated vehicle may be that if a rock or similar is dropped on the device, the flexibility of the device will cause the device to bend away and thus reduce the risk of getting broken due to the blow from the rock.

According to an embodiment of the present invention, the length of the flexible device in the loaded condition is at least 65% larger compared to the length of the flexible device in the unloaded condition. This may further increase the acceptable variations of the distance between the first and the second exhaust pipe when employing the articulated vehicle. An extension range of 65%-75% may provide good balance between the required stiffness of the spring for providing a controlled compression of the flexible device and the acceptable variations that the flexible device can provide for. According to other embodiments, an extension range of 65%-100% is considered to provide such a good balance.

According to other embodiments of the present invention, a distance between the first and second exhaust pipe when the articulated vehicle is in a fully pivoted state is less than 90% of the max length of the first tube when being in a fully extended state. According to other embodiments, this distance is less than 90% of the max extension of the helical extension spring. The max extension of the helical extension string is understood to mean an extension a little bit shorter than an extension wherein the spring is permanently set, that is when the spring is extended so far that its elastic properties have been exceeded and it does not return to its original condition upon release of load. According to other embodiments, the allowed extension of the first tube and the helical extension spring have other values which may be differing such that the spring may be allowed to be extended closer to its max extension compared to the first tube and vice versa. The advantage of never letting the first tube and/or the helical extension spring to be fully extended is that the risk of breakage of the components is reduced.

According to other embodiments of the present invention, the flexible device is adapted for enduring temperatures up to 580°C without substantial deformation. The average temperature of exhaust gases is 180 - 250 degrees Celsius, depending on the engine type. However, the flexible device must be able to withstand peak temperature of 450 - 500 degrees Celsius, and sometimes even higher peak temperatures due to the high speed of the exhaust gases directed by the flexible device.

According to other embodiments of the present invention, the flexible device further comprises a second tube being a heat resistant flexible tube enclosing the helical extension spring and the first tube. The articulated vehicle often is employed in environments where there is a risk of rocks falling on the flexible device, or dirt sticking to the flexible device. Moreover, the articulated vehicle, and thus the flexible device, may be exposed to high pressure cleaning. This may be harmful for the first tube and/or the helical extension spring and such a cover may protect these vital inner parts of the flexible device from dirt, blows by e.g. a rock and high pressure cleaning.

According to embodiments of the present invention, the second tube is fixed to the flexible device by hose clamps fixed to the first and second connection means. Since the second tube is enclosing the helical extension spring and the first tube, the second tube will interact with the spring and the first tube in compression and extension. Consequently it is enough if the tube is fixed to the flexible device at the ends of the second tube. The use of hose clamps fixed to the connection means provides for a simple and cheap attachment. A further advantage is that by fixing the second tube to the flexible device only by hose clamps, the second tube may easily be replaced. Since the flexible device often is employed in harsh environments, as described above, the second tube may be worn out and thus easy

replacement is advantageous.

According to other embodiments of the present invention, the helical extension spring is fixed to the first tube by means of a strip of a heat resistant material, and wherein the strip is fixed to the first tube over at least a part of the coils of the helical extension spring. By fixing the extension spring by means of a strip of material, the excessive material when the flexible device is compressed may be reduced compared to if the extension spring was fixed by a further tube. According to embodiments, the strip is fixed to the first tube by means of stitches of a thread made of heat resistant fibers. Using stitches for fastening the strip to the first tube may be a simple and cost efficient but still very durable way of fastening the strip. Moreover, stitches of heat resistant fibers may endure heat better than other fastening means such as gluing.

According to other embodiments of the present invention, at least some of the coils of the helical extension spring are fully enclosed by the strip of heat resistant material and the first tube. This may keep the spring firmly fixed to the first tube while reducing the material required for fastening the spring.

According to other embodiments of the present invention, the ends of the helical extension spring are fixed to the first and second connection means. As mentioned above, the helical extension spring can, without breaking or being deformed, withstand the torsional movement arising when the articulated vehicle is being employed in a coarse terrain. Consequently, the ends of the spring can be fixed to the first and second connection means, which in turn are fixed to the first and the second vehicle body. This may reduce the risk of the helical extension spring tearing the first and/or the second tube since the ends of the spring is fixed to the connection means. By fixing the first and second connection means to the vehicle bodies, the need for swiveling connection means is removed which reduce the complexity of the flexible device.

According to other embodiments of the present invention, the first and second connection means each comprises an inner metal pipe and an outer metal pipe, wherein a first end and a second end of the first tube is fixed to the first and second connection means respectively by positioning each end of the first tube between the inner and the outer metal pipe of the

corresponding connection means and mechanically pressing the inner and outer metal pipe together. An advantage of this embodiment may be that it is a simple and cheap way of fastening the first tube to the connection means. According to embodiments, the ends of the helical extension spring are fastened in the same way. According to embodiments, both an end of the first tube and the corresponding end of the helical extension spring is fixed to the corresponding connection means at the same manufacturing step, which may further simplify the manufacturing process.

According to embodiments, an outlet of the inner metal pipe for outflow of the exhaust gas from the first connection means is formed by an end portion of the inner metal pipe, the end portion being tapered in a flow direction of the exhaust gas. This embodiment may have two different advantages. First, by having such a tapered outlet, a laminar flow in the exhaust gas may be achieved. This may reduce the turbulence of the exhaust gases when the gases are directed in the flexible device. Second, by having a tapered outlet, the inner metal pipe may be designed such that the risk of tearing the first tube against the edge of the inner metal pipe is reduced. This will be further elaborated in the detailed section below.

According to embodiments of the present invention, an inlet of the inner metal pipe for inflow of the exhaust gas into the second connection means is formed by an end portion of the inner metal pipe, the end portion being widened in a flow direction of the exhaust gas. By having such a widened inlet, the inner metal pipe may be designed such that the risk of tearing the first tube against the edge of the inner metal pipe is reduced. This will be further elaborated in the detailed section below.

In a second aspect, the present invention provides an articulated vehicle comprising a first vehicle body, a second vehicle body, a first exhaust pipe fixed to the first vehicle body, a second exhaust pipe fixed to the second vehicle body, and a flexible device according to the first aspect for directing exhaust gases from the first vehicle body to the second vehicle body via the first exhaust pipe and the second exhaust pipe.

The second aspect may generally have the same features and advantages as the first aspect.

Other objectives, features and advantages of the present invention will appear from the following detailed disclosure as well as from the drawings. Brief description of the drawings

The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, where the same reference numerals will be used for similar elements, wherein:

figure 1 shows an articulated vehicle according to embodiments of the invention,

figure 2 shows a flexible device for directing exhaust gases between vehicle bodies of the articulated vehicle shown in figure 1 ,

figures 3a-b show the flexible device in an unloaded condition and in a loaded condition,

figure 4 describes the structure of the flexible device,

figure 5 shows the flexible device of figure 4 in cross section, figure 6 shows the connection means of the flexible device in cross section.

As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of embodiments of the present invention.

Detailed description

Figure 1 shows by way of example an articulated vehicle. The vehicle comprises a first vehicle body 104 and a second vehicle body 106. The articulated vehicle 100 is designed to be steered by bending the vehicle in the middle around a hitch assembly 1 12. The vehicle further comprises a first exhaust pipe 108 fixed to the first vehicle body 104, and a second exhaust pipe 1 10 fixed to the second vehicle body 106. The vehicle further comprises a flexible device 102 for directing exhaust gases from the first vehicle body 104 to the second vehicle body 106 via the first exhaust pipe 108 and the second exhaust pipe 1 10.

Figure 2 shows the flexible device 102 when mounted between the first exhaust pipe 108 the second exhaust pipe 1 10. The flexible device 102 is connected to the first exhaust pipe 108 via a first connection means 202a and to the second exhaust pipe 1 10 via the second connection means 202b.

Since a distance between the two exhaust pipes 108, 1 10 may be largely varying, due to the changes in the distance and angular relationship between the first vehicle body 104 and the second vehicle body 106 during operation of the articulated vehicle 100, the flexible device needs to accommodate such varying distances. According to some embodiments, a minimum distance between the first exhaust pipe 108 and the second exhaust pipe 1 10 is 700 mm. When the articulated vehicle 100 is deflected to its maximum steering angles, this distance between the first exhaust pipe 108 and the second exhaust pipe 1 10 may be 1000-1400 mm, depending on the type of articulated vehicle. As understood by the skilled person, this distance may scale depending on the size of the articulated vehicle, such that for large vehicle the minimum distance may be 900 and the maximum distance may be 1300-1800 mm. The same goes for smaller vehicles where the distances are reduced accordingly. The distances further depend on the type of a hitch assembly that is used between the two vehicle bodies.

The structure of the flexible device 102 will now be described in conjunction with figure 4 and 5. Figure 4 shows a perspective view of the first connections means 202a and how the connections means 202a is fixed to the remaining parts of the flexible device 102. Figure 4 further shows the structure of the flexible components of the flexible device 102. Figure 4 thus show a first end portion of the flexible device, i.e. the portion closest to the first vehicle body 104 shown in figure 1 . For illustrative purposes, parts of the components of the flexible device 102 are cut away in figure 4. Figure 5 shows the flexible device 102 shown in figure 4 in cross section. It may be noted that a corresponding second end portion of the flexible device 102, i.e. the portion closest to the second vehicle body 106 shown in figure 1 and comprising the second connection means 202b, may be structured in the same way as the first end portion shown in figure 4 and 5.

The flexible device 102 comprises a first tube 408 being a heat resistant flexible tube. The flexible device 102 further comprises a helical extension spring 402, wherein the first tube 408 is contained by and fixed to the helical extension spring 402. By fixing the first tube 408 to the helical extension spring such the first tube may be compressed and extended within the spring, the flexible device may have a loaded and unloaded condition, wherein a length of the flexible device 102 in the loaded condition is at least 50% larger compared to the length of the flexible device 102 in the unloaded condition. The flexible device 102 further comprises a second tube 404 being a heat resistant flexible tube enclosing the helical extension spring 402 and the first tube 408. The second tube 404 is included in the flexible device in order to protect the vital inner parts, i.e. the first tube 408 and the spring 402, from the harsh environment where the flexible device often is employed, e.g. an environment where stones or other structure may fall onto the flexible device. The second tube is however optional. According to embodiments, the second tube 404 is fixed to the flexible device 102 by hose clamps fixed to the connection means 202a.

Figure 4 and 5 describes the flexible device 102 in a loaded condition, i.e. a condition where the articulated vehicle 100 in figure 1 is deflected to its maximum steering angles (or in its fully pivoted state), such that this distance between the first exhaust pipe 108 and the second exhaust pipe 1 10 is at its maximum. As can be seen in figure 4 and 5, the first tube 408 and the second tube 404 are not in their fully extended state. On the contrary, both tubes 408, 404 are slightly corrugated. According to embodiments, the distance between the first 108 and second 1 10 exhaust pipe when the articulated vehicle 100 is in a fully pivoted state is less than 90% of the max length of the first tube 408 when being in a fully extended state. According to embodiments, this is equally valid for the second tube 404. This reduces the risk of damaging the tubes 408, 404 by extending them beyond their fully extended state, which would risk tearing of the tubes 408, 404. As discussed above, the length of the flexible device 102 in its loaded condition may be somewhere between 50-120% larger compared to the length of the flexible device 102 in the unloaded condition. This means that the distance between each coil of the spring 402 may be reduced by approximately 50%, but not much more, when being in the unloaded condition. Consequently, the spring 402 is not close- wound (i.e. coiled with adjacent coils touching) even in the unloaded condition, thereby allowing (corrugated) parts of the first tube 408 to be placed between the coils of the spring 402 without risking wear of the first tube 408. According to embodiments, the pitch of the spring 402 in its unloaded condition is 10-20 mm. The wire diameter of the coils of the spring may be 2 - 8 mm.

According to embodiments, a typical diameter of the opening 416 of the flexible device may be 100-140 mm. This is large enough for allowing transmission of exhaust gases from the first vehicle body to the second vehicle body of the articulated vehicle, even when a motor of the articulated vehicle is powerful. Typically, the inner diameter of the first tube 408 is approximately the same as the diameter of the opening, i.e. 100-140 mm. This size of the first tube 408 allow for a not to heavy flexible device. A heavy flexible device would require a more powerful spring in order to contract when the distance between the first 108 and second 1 10 exhaust pipe is reduced. This may not be advantageously for the abilities of the flexible device to handle rotational movements between the first 104 and second 106 vehicle bodies. Further, a larger diameter of the flexible device 102 leads to a higher manufacturing cost due to the larger and more powerful spring, and the increased area of the hoses 404, 408.

In figure 4 and 5, the helical extension spring 402 is fixed to the first tube 408 by means of a strip 406 of a heat resistant material, wherein the strip 406 is fixed to the first tube 408 over at least a part of the coils of the helical extension spring 402. The strip 406 may for example be fixed to the first tube by means of stitches of a thread made of heat resistant fibers. At least some of the coils of the helical extension spring 402 are fully enclosed by the strip 406 of heat resistant material and the first tube 408. According to some embodiments, all the coils are fully enclosed, but according to other embodiments, for example the coils closest to the connection means 202a is not fixed to the first hose 408. According to some embodiments, the strip 406 is a continuous piece of heat resisting material, but the strip 406 may also comprise several adjacent strips of heat resisting material. Using several adjacent strips 406 may simplify the process of fixing the spring 402 to the first hose 408. Using one continuous strip 406 may be advantageous for increasing the lifetime of the flexible device 102.

The connection means 202a comprises an inner metal pipe 424 and an outer metal pipe 422. The end of the first tube 408 is fixed to the connection means 202a by positioning the end of the first tube 408 between the inner 424 and the outer 422 metal pipe of the connection means 202a and mechanically pressing the inner 418 and outer 410 metal pipes together. The end of the helical extension spring 402 is fixed to the connection means 202a. According to embodiments, this fixation is done in the same manufacturing step as the fixation of the first tube 408 to the connection means 202a.

According to other embodiments, the first tube 408 extends further than the coils of the spring 402, such that the inner tube is fixed between the inner 424 and outer 422 metal pipes while the spring is fixed to the connection means 202a in some other suitable way, for example by welding.

The second tube 404 is fixed to the flexible device 102 by a hose clamp 418 fixed to the connection means 202a. By forming the connection means with circumferentially protruding sections 412 and 426, wherein the distance between them matches a width of the hose clamp 418, a firm fixation of the second tube 404 may be achieved. However, the design of the connection means 202a in figure 4-6 is just by way of example, according to some embodiments, the hose clamp 418 is fixed around the outer metal pipe 422.

The outer metal pipe 422 may be designed such that a portion 410 of the outer metal pipe 422 is bent around the protruding section 412 when the outer metal pipe 422 has been mechanically pressed together with the inner metal pipe 424. This may be advantageous in that the outer metal pipe 422 is firmly fixed to the inner metal pipe 424. The outer metal pipe 422 may comprise such a bent portion 410 before being mechanically pressed to the inner metal pipe 424, or the manufacturing step of mechanically pressing the two pipes 424, 422 together may form such a bent portion.

The flexible device 102 may further comprise at least one separate coil 420 which is not connected to the spring 402. The separate coil(s) may be fixed to the first hose 408 by means of a strip of heat resistant material in the same way as the spring 402 is fixed to the first hose 408. The separate coil(s) 420 may be used for firmly fixing the first hose 408 to the connection means 202a by positioning one coil 420 adjacent to a protrusion 414 when

mechanically pressing the inner 424 and the outer 422 metal pipes of the corresponding connection means 202a. Any further separate coil(s) may be used for further fix the first hose 408 to the connection means 202a. As understood from above, separate coil(s) may be used for fixing the first hose 408 to the connection means 202b as well. According to embodiments, the flexible device 102 is adapted for enduring temperatures up to 580°C without substantial deformation. This is achieved by using heat resistant material for the first hose 408, the second hose 404, the strip 406 and the thread fixing the strip 406 to the first hose 408. In the following, such a heat resistant material is exemplified. Is should be noted though, that the materials is just examples, and that any material able to withstanding temperatures up to 580°C, or at least able to withstand a peak temperature of 450 - 500° Celsius may be used for the invention.

The main element of the heat resistant material is to withstand the high temperature and chemical environment of exhaust gases. The material should also be flexible and have a high resistance to fatigue since the flexible properties of the flexible device, along with the conditions under which the flexible device is employed, may cause the flexible device, and thus the materials used in the flexible device to compress and stretch. The material used may be a coated fabric. The fibers in the fabric may be made of glass fiber or a combination of glass fibers and polyaramide fibers. The fabric may be coated with a layer of material with high temperature resistance such as silicone or Teflon or other materials with high temperature and chemical resistance. The heat resistant material can also be made in a combination of layers of such coated fabrics. The material used may also be metalized fabrics formed by an aluminisation process, for example the material

Reflespace® provided by Dickson PLT or a material with similar properties. According to some embodiments, the material of the first tube 408 may differ from the material of the second tube 404.

Figures 3a-b show by way of example the flexible device in an unloaded condition and in a loaded condition, respectively. As can be seen in figure 3b, even in the loaded condition, the flexible device is in a corrugated state.

Figure 6 shows by way of example the inner metal pipe 424 of the connection means 202a, 202b of the flexible device 102 in cross section. Figure 6 thus represents both the first connection means 202a and the second connection means 202b. For the first connection means 202a, an outlet of the inner metal pipe for outflow of the exhaust gas from the first connection means 202a is formed by an end portion 614 of the inner metal pipe 424, the end portion 614 being tapered in a flow direction of the exhaust gas. This means that for the first connection means 202a, the exhaust gas will flow from right to left in figure 6. The angle 602 of the tapered end portion may range between 10-30°. In one embodiment, the angle of the tapered end portion of the first connection means 202a is 20°.

According to embodiments of the second connection means 202b, an inlet of the inner metal pipe 424 for inflow of the exhaust gas into the second connection means 202b is formed by an end portion 614 of the inner metal pipe 424, the end portion 614 being widened in a flow direction of the exhaust gas. This means that for the second connection means 202b, the exhaust gas will flow from left to right in figure 6. The angle 602 of the widened end portion may range between 10-30°. In one embodiment, the angle of the widened end portion of the first connection means 202a is 20°. It may be noted that according to some embodiments, the angle 602 for the first connection means 202a is larger than the angle 602 for the second connection means 202b.

The tapered and widened end portions 614 may have the advantage that the risk of tearing the first tube 408 against the edge 616 of the inner metal pipe is reduced. Moreover, by having a tapered end portion 614 of the first connection means 202a, a laminar flow through the flexible device 102 may be achieved, which may be advantageous.

A length 612 of the connection means 202a, 202b may be 130 mm. The diameter 608 of the tapered/widened end portion may be 120 mm. A general diameter 604, i.e. not including the protrusions 412, 414, 426 and the end portion 614, of the flexible device may be 123 mm. The thickness of the inner metal pipe may be 3-6 mm. A diameter of the right most protrusion 426 may be 145-147mm. A diameter of the two smaller protrusions may be 132- 134 mm. The above measures are only disclosed by way of example, and may for example vary with ±10% for each measure.

It may be noted that the design of the connection means 202a, 202b may be used in other applications where a hose or similar needs to be firmly fixed to a connection means, wherein the hose may be twisted and turned in use. Using the design of the connection means shown in fig 4-6 may be advantageous in other applications since the risk of tearing the hose against the edge 616 of the connection means is reduced. Moreover, the angular end portion 614 may be advantageous in applications where a laminar flow of the fluid/gas flowing through the connected hose is needed.