Line element for compensating for expansions and/or relative movements

Abstract

A line element for compensating for expansions and/or relative movements within a line through which fluid can flow, comprising a ring-corrugation or helical-corrugation bellows 1 and a hose 3, which is arranged coaxially in the interior of the bellows 1 and is made of a dimensionally stable material, for flow-guidance purposes. The hose 3 has a number of individual, essentially dimensionally stable ring-form hose elements 4 which are plugged axially one inside the other so as to be retained such that they can be moved axially and/or angularly in relation to one another between a compressed position and an extended position. A method for producing such a line element is also provided.

Claims

1. A line element for compensating for at least one of expansions or relative movements within a line through which fluid can flow, the line element comprising a ring corrugation or helical-corrugation bellows (1) and a hose (3), which is arranged coaxially in an interior of the bellows (1) and is made of a dimensionally stable material, for flow guidance purposes, the hose (3) comprises a number of individual, essentially dimensionally stable ring form hose elements (4) arranged axially adjacent to one another having portions which are plugged axially one inside the other and retained together such that the hose elements (4) are movable axially in relation to one another between a compressed position and an extended position, and the hose (3) is made up of at least first and second different groups of said ring form hose elements (4), with a plurality of the hose elements being in each of the first and second different groups, the hose elements of each said group having a ring form about an axis that is different than a ring form about the axis of the hose elements of the other said group.

2. The line element as claimed in claim 1, wherein the hose elements (4) have a closed or openable circumference.

3. The line element as claimed in claim 1, wherein the first group of hose elements (4) has a circular ring shape and the second group of hose elements has a non-circular ring shape.

4. The line element as claimed in claim 3, wherein the hose (3) is made up of hose elements (4) which belong alternately to the first and the second group of hose elements.

5. The line element as claimed in claim 1, wherein in each case two adjacent ones of said ring form hose elements (4) are interlinked with one another at at least one point of circumferences thereof.

6. The line element as claimed in claim 1, wherein the bellows (1) includes axial ends, and a flange (2) on which the hose (3) is fastened is located at each of the axial ends.

7. The line element as claimed in claim 6, further comprising a clearance (8) located between the hose (4) and the bellows (1), and in a region of the flanges (2), the hose (3) has a respective hose element (4) formed as an end piece (5) that has an enlarged radial extent.

8. The line element as claimed in claim 1, wherein the hose elements (4) have, in axial sequence, a first sub portion (10) and a second sub portion (11), which are connected by a transition portion (12), and the first sub portion (10) has a radially smaller extent than the second sub portion (11).

9. The line element as claimed in claim 8, wherein, at an end of the first sub-portion (10) which is directed away from the second sub portion (11), the first sub portion (10) is provided with a radially widened, first end portion (13), and at an end of the second sub-portion (11) which is directed away from the first sub portion (10), the second sub portion (11) has a second end portion (14) of reduced radial extent, and the radial extents of the first (13) and second end portions (14) are selected such that the first end portion (13′) and the second end portion (14) of two hose elements (4, 4′) plugged one inside the other engage behind one another in an axial direction in order to form an axial pull out prevention arrangement and to define the extended position.

10. The line element as claimed in claim 9, wherein the radial extents of the first and second end portions (13, 14) are selected such that the first (13′) and second end portions (14) of two of said hose elements (4, 4′) plugged one inside the other overlap with the transition portion (12), as seen in axial projection, in order to form an axial stop, and to define the compressed position, when the two hose elements (4, 4′) are pushed together.

11. The line element as claimed in claim 10, wherein at least one of the first sub portion (10) or the second sub portion (11) of one of the first and second different groups of said ring form hose elements (4) is cylindrical.

12. The line element as claimed in claim 10, wherein the first (13) and second end portions (14) are radially running angled sections of the first (10) and second (11) sub portions.

13. The line element as claimed in claim 1, wherein the hose elements (4) are produced from metal having a material thickness between 0.1 mm and 0.4 mm.

14. The line element as claimed in claim 13, wherein the hose (3) is made up of at least 3 and at most 20 hose elements (4).

15. The line element as claimed in claim 1, wherein the bellows (1) is a metal bellows and has 2 to 15 corrugations.

16. An exhaust gas system comprising the line element as claimed in claim 1.

17. The exhaust gas system of claim 16, wherein the hose (3) is located within an expansion compensation body in the exhaust system of a combustion engine, and the expansion compensation body is adapted to be arranged between a combustion engine and an emission control device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) An exemplary embodiment for a line element configured according to the invention will be explained and described in more detail hereinbelow with reference to the accompanying drawings, in which:

(2) FIG. 1 shows a lateral sectional illustration of a line element configured according to the invention;

(3) FIG. 2 shows a view of the hose from the line element from FIG. 1;

(4) FIG. 3 shows a section taken along line B-B from FIG. 2;

(5) FIG. 4 shows an axial view of a hose element which is used in the hose from FIGS. 2 and 3;

(6) FIG. 4A schematically shows an axial view of a portion of a hose having a hose element with an oval ring shape.

(7) FIG. 5 shows a sectional illustration taken along line A from FIG. 4;

(8) FIG. 6 shows the detail B from FIG. 5;

(9) FIG. 7 shows a schematic sectional illustration of another exemplary embodiment of a hose configured according to the invention, during production thereof;

(10) FIG. 8 shows a schematic sectional illustration of a further exemplary embodiment of a hose configured according to the invention, during production thereof; and

(11) FIG. 9 shows a detail of a plan view of a hose which is configured as in FIGS. 1 to 6 and has had follow-up treatment included in its production.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(12) FIG. 1 shows a lateral sectional illustration of a line element configured according to the invention for the purpose of compensating for expansions and/or relative movements, wherein the present exemplary embodiment is an expansion body for the exhaust system of a motor vehicle with a diesel engine. The expansion body serves there to compensate for thermal expansions, relative movements within the exhaust-gas line and, if appropriate, installation tolerances; for this purpose, it is installed in the exhaust system in the vicinity of the engine and is also located upstream of the emission-control devices.

(13) Said line element, designed in the form of an expansion body, essentially comprises a ring-corrugation bellows 1 which is made of stainless steel and, at each of its axial ends, has a flange 2, 2′. A hose 3 configured according to the invention is arranged coaxially within the bellows 1, said hose 3 likewise consisting of stainless steel and being made up of a number of individual, ring-form hose elements 4, 4′, 4″. Provided in the region of the flanges 2, 2′ of the bellows 1 are two hose elements which are designed in the form of end pieces 5, 5′, have an enlarged radial extent in relation to the other hose elements 4, 4′, 4″ and therefore extend up to, and onto, the flanges 2, 2′ of the bellows 1. They are welded there to the flanges 2, 2′ and a respective sleeve 6, 6′, and this therefore establishes a fixed connection between the hose 3 and the bellows 1 at both axial ends of the line element.

(14) The hose elements 4, 4′, 4″ can move axially relative to one another, limitation being provided by a compressed position and an extended position, wherein the two hose elements 4, 4′ arranged on the left-hand side of the illustration are located in the compressed position, whereas the rest of the hose elements 4″ are located in an extended position in relation to one another. The axial movement capability, moreover, makes it possible for two hose elements to tilt (not illustrated here) in relation to one another, which all results in axial and lateral movement capability of the hose 3.

(15) In accordance with the use purpose, the line element illustrated in FIG. 1 is of relatively short design, although it has a large cross section for the fluid flow indicated by an arrow 7. The line element has the axially short construction owing to the merely small amount of installation space available in the exhaust system in the vicinity of the engine. In order to ensure the desired movement capability of the line element even in the case of small axial dimensionings, the bellows 1 is provided with only small wall thicknesses, and it has deep corrugations. Accordingly, it is necessary for the bellows 1 to be shielded, in particular, thermally from the fluid flow 7, which may be at temperatures of around 600° C. The thermal shielding takes place by way of the flow-guiding hose 3 and an insulating-action clearance 8 between the hose 3 and the bellows 1. The plugged-together design of the hose 3 nevertheless gives the latter a large flow cross section, without there being any risk of it coming into undesirable contact with the bellows 1 in the case of lateral and/or angular movements, or on account on oscillating movements.

(16) Moreover, the hose elements 4, 4′, 4″ plugged one inside the other mean that there is no need for the hose 3 to be cut to length in order to be installed in the bellows 1, so that there is no risk of any burr formation and the cleanliness requirements for the envisaged use purpose can be met without the hose 3 being subjected to any high-outlay follow-up machining.

(17) FIG. 2 shows an axial view of the hose 3 from FIG. 1, while FIG. 3 is a sectional illustration taken along line B-B from FIG. 2.

(18) As, in particular, FIG. 3 shows clearly, the hose 3 illustrated here has been deflected laterally in relation to a hose axis 9, three hose elements 4, 4′, 4″ having been tilted upward in each case, whereas three other hose elements 4′″, 4″″, 4′″″ have been tilted down in the opposite direction. Three hose elements each here, on the side illustrated at the top and bottom in FIG. 3, are located in the compressed position, whereas they are illustrated in the extended position on the opposite side.

(19) The two end pieces 5, 5′, which are radially enlarged in relation to the rest of the hose elements 4, 4′, 4″, etc., are likewise retained in an axially (and, to this extent, also angularly) movable manner on their adjacent hose elements 4, 4′″″ by means of a plug-in connection.

(20) The design of one of the hose elements 4 used in the hose 3 of the present exemplary embodiment is illustrated in more detail in FIGS. 4, 5 and 6. FIG. 4 here shows an axial plane view, FIG. 5 shows a side view with a partial section taken along line A, and FIG. 6 shows the detail B from FIG. 5.

(21) As FIGS. 5 and 6 show clearly, the hose element 4 illustrated here comprises a first sub-portion 10 and a second sub-portion 11, which are both cylindrical and are connected to one another via a transition portion 12. The first sub-portion 10 has a smaller radial extent than the second sub-portion 11. The first sub-portion 10 is provided, at its end located opposite the transition portion 12, with a first end portion 13, which is radially widened and has a maximum radial extent which is somewhat smaller than the inner radial dimension of the second sub-portion 11, it therefore being possible for the first end portion 13 to slide axially within the second sub-portion 11′ of an adjacent hose element.

(22) Conversely, the second sub-portion 11 has, at its end located opposite the transition portion 12, a second end portion 14, of which the radial extent is smaller than that of the second sub-portion 11. The radial extent of the second end portion 14 is also slightly smaller than the radial extent of the first end portion 13, and a first end portion 13′ of an adjacent hose element 4′ can therefore interlink with the second end portion 14 such that the two end portions 13′, 14 form a pull-out prevention means. At the same time, the two end portions 13′, 14 are coordinated with one another such that joining forces which exceed the axial forces at play when the line element is being used as intended can be used to plug together two adjacent hose elements 4, 4′ such that the two end portions 13′, 14 move over one another. The rounded shape of the two end portions 13′, 14 ensures a soft end stop in the extended position.

(23) Moreover, in conjunction with the transition portion 12, the radially widened first end portion 13 ensures an axial stop when an adjacent hose element 4′ is seated, by way of its first end portion 13′, in the second sub-portion 11 and is moved axially further into the hose element 4. The compressed position between two hose elements 4, 4′ is defined by the first end portion 13 stopping against the transition portion 12.

(24) Therefore, a hose element 4 of a hose of the present exemplary embodiment for a line element according to the invention has a more or less S-shaped profile, as is known essentially from conventional strip-wound hoses with a hook profile. However, the hose 3 here, rather than being wound, is made up of individual ring-form hose elements 4 which are plugged one inside the other and, as FIGS. 1 and 3 show clearly, can be moved axially and/or angularly in relation to one another between a compressed position and an extended position.

(25) The radial extents of the first end portion 13 (h1), of the transition portion 12 (h2) and of the second end portion 14 (h3) are selected in conjunction with a material thickness such that the first end portion 13 of a first hose element 4 comes into frictional contact with the inner surface of the second sub-portion 11′ of a second hose element 4′ and, in the compressed position, strikes against the transition portion 12′ and, in the extended position, strikes against the second end portion 14′. By virtue of the hose elements 4, 4′ being produced in an appropriate manner, this frictional contact can be adjusted extremely accurately to desired set-point values, and this therefore gives rise to a desirable internal friction in the made-up hose 3 and therefore to a desirable damping action in relation to the natural frequency of the bellows 1 on account of the losses associated with the internal friction. The rounded shape of the first end portion 13 makes it possible here for the internal friction to remain within the set-point values even in the case of angular movements between two hose elements 4, 4′.

(26) FIG. 4A schematically shows that there can be a different group of hose elements 4′ which have a different ring shape, and the hose 3 can be made up of different groups of hose elements 4, 4′ which have different ring shapes. This may be implemented, for example, such that a first group of hose elements 4 have a circular ring shape, as shown in FIG. 4, whereas a second group of the hose elements 4′ have a non-circular ring shape, in particular an oval ring shape, as shown in FIG. 4A.

(27) FIGS. 7 to 9 use schematic illustrations to visualize examples of how a method according to the invention can be used.

(28) FIG. 7 is a schematic sectional illustration of a row of ring-form hose elements 4, 4′, 4″, which have been positioned one on the other in order to be plugged one inside the other to make a hose 3. For this purpose, radially inner portions of the ring-form hose elements 4, as indicated by the arrows 15, are widened in the radially outward direction and plastically deformed to give, in the end, a hose which looks essentially like that in FIGS. 1 to 3. This is because the radially inner part of the hose elements 4, 4′, 4″ is provided, in an end region, with outwardly oriented angled sections 16 which, following deformation on account of the widening forces 15, form a stop surface in order to define the compressed position and the extended position of the finished hose 3.

(29) FIG. 8 shows, once again in a schematic sectional illustration, a variant of ring-form hose elements 4, 4′, 4″ which, in the first instance, can be arranged, without a form fit, in a row one behind the other, and in abutment against one another, and can be plastically deformed into a hose 3 according to the invention, as is illustrated in FIGS. 1 to 3. Here too, each ring-form hose element 4 comprises a first sub-portion 10 with a radially widened, first end portion 13, a second sub-portion 11 with a second end portion 14 of reduced radial extent, and a transition portion 12, which connects the first sub-portion 10 and the second sub-portion 11.

(30) The end portions 13, 14 here, rather than being oriented radially, taper off in a flat state, and therefore the individual hose elements 4, 4′, 4″ can be moved axially in relation to one another. An axial deformation force, which is indicated by arrows 17, can be used to compress, and plastically deform, the hose elements 4, 4′, 4″, wherein the first and second end portions 13, 14 run up against the transition portions 12 and consequently deform in such a way that they then run radially and form stop surfaces which define the compressed position and the extended position of the then finished hose 3.

(31) Finally, FIG. 9 shows a detail of a plan view of a hose 3 configured as in FIGS. 1 to 6. The special feature of this exemplary embodiment is that, once the hose elements 4, 4′, 4″ have been plugged together, the hose 3 has been subjected to follow-up machining by way of the introduction of interlinking formations 18, produced by the hose elements 4 being pressed locally. Such local interlinking formations 18 restrict the movement capability of the hose elements 4, 4′, 4″ in relation to one another—merely locally—and therefore any rattling as a result of the hose elements 4 moving relative to one another is ruled out.