Highly flexible conduit element and method for producing a flexible conduit element

Abstract

The invention relates to a flexible conduit element (1) comprising: a metallic corrugated hose portion or bellows (2); at least at one end of the corrugated hose portion or bellows (2), a tubular connection part (4) connected to the corrugated hose portion or bellows (2) via an annular counterpart (3), the counterpart (3) being integrally bonded on one side to the corrugated hose portion or bellows (2) and on the other side to the connection part (4); and a tubular inner component (6) which is held in the corrugated hose portion or bellows (2) and in the counterpart (3) and consists of a plastic, in particular an elastomer material, preferably of fluoro rubber. The flexible conduit element (1) is characterized in that a continuous circumferential free space (5) is formed axially between the connection part (4) and the counterpart (3); and the inner component (6) has, in a region of the end, a circumferential projection (6a) which extends radially outwards with respect to a longitudinal axis (L) of the conduit element (1) and by means of which the inner component (6) engages in the free space (5).

Description

[0001] Title Highly flexible conduit element and method for producing a flexible conduit element

[0002] Description

[0003] The invention relates to a flexible conduit element in claim 1 and to a method for producing a flexible conduit element in claim 15.

[0004] EP 3 951 228 A1 discloses a flexible conduit element according to the preamble of claim 1. The inner component, in the form of an extruded PTFE liner, is held with a substantially axial extension between an inner and an outer connecting part, to which another connecting part is axially connected. Due to this axially long connection geometry, the conduit exhibits relatively low flexibility in limited installation space. This is also due to the fact that the PTFE liner used as the inner component only allows for relatively large bending radii.

[0005] If one wanted to use a more elastic, rubber-like liner as the inner component of the previously known pipe element to improve flexibility, the existing connection concept would be unusable, as the liner would eventually creep out of the connection, leading to a loss of tightness. Therefore, a new type of connection is required.

[0006] The invention is based on the object of specifying a flexible conduit element and a method for its production which - compared to the prior art - enables improved flexibility with the same overall length or at least the same flexibility with a shortened overall length of the flexible conduit element, wherein permanent tightness is to be ensured in order to enable, in particular, highly cleanliness-critical uses.

[0007] These piping elements, with increased flexibility and improved sealing, can and should be used in a projection exposure system for semiconductor lithography. Cooling lines can be used in such projection exposure systems to cool elements within the system. With these cooling lines, it is important to minimize the transmission of pressure fluctuations of the cooling medium to the overall system and to ensure that the high cleanliness requirements within the system are met.

[0008] This object is achieved according to the invention by a flexible conduit element having the features of claim 1. It is also achieved by a method for producing a flexible conduit element having the features of claim 15.

[0009] Advantageous further developments of the inventive idea are defined in the respective subclaims.

[0010] According to the invention, a flexible conduit element comprises: a metallic corrugated hose section or bellows; at at least one end of the corrugated hose section or bellows, a tubular connecting part which is connected to the corrugated hose section or bellows via an annular counterpart, wherein the counterpart is integrally connected to the corrugated hose section or bellows on one side and to the connecting part on the other side; and a tubular inner component made of a plastic, in particular an elastomer material, preferably made of fluororubber (FKM), which is received in the corrugated hose section or bellows and in the counterpart, and / or a tubular outer component made of a plastic, in particular an elastomer material, preferably made of fluororubber (FKM), which surrounds the corrugated hose section or bellows and the counterpart.The flexible conduit element according to the invention is characterized in that a continuous circumferential free space is formed axially between the connecting part and the counterpart; and in that the inner component and / or the outer component has a circumferential projection in a region of said end, which extends radially outwards (for the inner component) or radially inwards (for the outer component) with respect to a longitudinal axis of the conduit element, and with which the inner component or the outer component engages in the free space. In other words: the inner component or the outer component is received in the free space with its projection. The inner component or the outer component is thus advantageously held in the free space by clamping between the counterpart and the connecting part. This enables a particularly flexible solution with high mobility in every direction of movement.

[0011] The ring-shaped counterpart, which can also be referred to as a weld-on part or functions as such, thus ensures the connection between the connecting part and the corrugated hose section or bellows.

[0012] Preferably, the flexible line element is identical at both ends and designed as described above.

[0013] The connecting part and the counterpart are preferably made of a metal, e.g. stainless steel, and the material connection between the two parts is a circumferential welded joint.

[0014] The corrugated hose section, or bellows, is preferably designed with a ring-shaped corrugation. For the sake of simplicity, it will be referred to simply as the "bellows" below.

[0015] Thanks to the innovative connection geometry, which is associated with the aforementioned special design of the inner component with the aforementioned circumferential projection, it is now possible to use a more elastic, rubber-like liner, e.g., an injection-molded part made of FKM, as the inner component to improve the flexibility of the line element, something that would have been impossible with the previous connection concept or would have led to a loss of tightness in the long term. With the same length, the line element can thus be made more flexible; at the same time, the same flexibility as before can be achieved with a shorter overall length.

[0016] Ensuring tightness is particularly relevant for the functional performance of the piping element, especially with regard to preventing leaks into the space between the inner component and the bellows.

[0017] The production of a flexible conduit element, in particular the flexible conduit element according to the invention, can be carried out as follows: i) providing a metallic corrugated hose section or bellows; ii) materially bonding an annular counterpart to at least one end of the corrugated hose section or bellows; iii) introducing a tubular inner component, in particular made of an elastomer material, into the corrugated hose section or bellows and into the counterpart, in particular upon radial compression of the inner component, which has a circumferential projection in a region of said end, which projection extends radially outward with respect to a longitudinal axis of the conduit element; iv) axially attaching a tubular connecting part to the counterpart, forming a continuously circumferential free space axially between the connecting part and the counterpart, such that the inner component engages with its projection in the free space;v) permanent, preferably material-locking connection of the connecting part and the counterpart by clamping or pressing the inner component between the connecting part and the counterpart in an area of ​​the free space;

[0018] The following embodiments of the invention have proven to be particularly advantageous in practice: A first embodiment of the flexible line element according to the invention is characterized in that the free space has an undercut effective in the radial direction.

[0019] This further improves the holding effect on the inner component. A "radially effective undercut" is an undercut that counteracts a radial pull-out movement. The actual recess forming the undercut therefore extends in the axial direction.

[0020] Another embodiment of the flexible conduit element according to the invention is characterized in that the inner component has a bulge on the projection in the axial direction, which bulge engages with the undercut.

[0021] Due to the geometric similarity, this is also referred to as the "P-geometry" of the inner component or projection. This allows the holding effect on the inner component to be further improved.

[0022] A further embodiment of the flexible line element according to the invention is characterized in that the undercut is formed in the counterpart.

[0023] This has proven particularly advantageous in practice. However, as an alternative (or additional) option, it is also possible to form the undercut in the connecting part, provided the inner component in the area of ​​the projection is also designed accordingly.

[0024] Yet another embodiment of the flexible conduit element according to the invention is characterized in that the undercut has a rounded inner contour. This effectively and reliably reduces the impact of damage on the inner component, which can extend its service life.

[0025] Yet another embodiment of the flexible conduit element according to the invention is characterized in that the bulge of the inner component has an outer contour complementary to the undercut or to its inner contour.

[0026] Investigations by the applicant have shown that the safety and tightness of the connection can be further improved in this way.

[0027] An advantageous embodiment of the flexible line element according to the invention is characterized in that a web delimiting the undercut in the radial direction inwards has a rounded outer contour.

[0028] In this way, there can be no damage to the internal components in this area either.

[0029] A particularly advantageous embodiment of the flexible line element according to the invention is characterized in that the projection fills the free space and in particular the undercut only to a fraction, ie not completely.

[0030] This ensures that blockages and subsequent leaks do not occur when joining the joint, which could occur if the projection were "too large" or too bulky for the clearance. This design therefore creates a kind of "clearance reserve."

[0031] An advantageous embodiment of the flexible conduit element according to the invention is characterized in that the inner component is arranged at a clear distance in the radial direction from the corrugated hose section or bellows. In this way, there is no risk that the inner component will negatively influence the inherent flexibility of the bellows. Furthermore, the resulting gap between the bellows and the liner or inner component can achieve pressure damping of FIV (so-called "flow-introduced vibrations") and compensate for assembly tolerances while maintaining the most laminar flow possible. Furthermore, the inner component enables improved flow guidance, since, unlike with bellows, no turbulence occurs.

[0032] FIVs are particularly critical because they can cause an entire system in which the flexible line element is integrated to vibrate and lead to deviations in production.

[0033] A particularly advantageous embodiment of the flexible conduit element according to the invention is characterized in that a clear inner diameter of the inner component is equal to a minimum clear inner diameter of the connecting part, which is preferably widened towards its free end.

[0034] This effectively prevents the formation of vortices within the flexible pipe element, so that no pressure losses occur and / or no disturbing noise is generated.

[0035] Another embodiment of the flexible conduit element provides that the inner component has a radially outer groove into which the counterpart preferably engages in a form-fitting manner.

[0036] This creates an additional sealing lip, which increases security against leakage into the gas space between the inner component and the bellows. Yet another embodiment of the flexible conduit element provides that the inner component has a further radially outer circumferential projection that rests against the counterpart on a side facing away from the connecting part, or at least one further radially outer circumferential projection that engages a groove arranged on an inner side of the counterpart.

[0037] This can further improve leak resistance. In particular, the additional projection and groove can be triangular or semicircular in cross-section. A P-shape or rectangular shape is also possible. The additional projection, in particular, can be vulcanized to the material of the inner component.

[0038] Yet another embodiment of the flexible conduit element according to the invention is characterized in that the counterpart has an axial centering projection at its end and the connecting part has a complementary recess on its side facing the counterpart, wherein the counterpart engages in the recess with the centering projection, or vice versa.

[0039] Such a design facilitates the proper joining of the connecting part and the counterpart.

[0040] Complementary thread structures are present in the area of ​​the centering projection and the recess. This allows the sealing structure (i.e., in particular, the projection of the inner component) to be compressed in a defined manner. After screwing, an additional external weld seam may be required to ensure tightness.

[0041] Yet another embodiment of the flexible conduit element according to the invention is characterized in that the connecting part is flat on a side surface facing the free space, wherein the side surface preferably extends exclusively in the radial direction. Such a configuration has proven particularly easy to handle in tests conducted by the applicant.

[0042] A further embodiment of the flexible line element according to the invention, which can be based in particular on the above-mentioned embodiment, is characterized in that a continuously circumferential ring part is arranged between a terminal end face of the inner component and the connecting part, in particular on its (radially extending) side surface.

[0043] Such a ring part can exert additional pressure on the inner component, especially in the area of ​​the projection, and thus have a particularly positive influence on the achievable holding effect.

[0044] In order to be able to exploit the diverse potential advantages of the ring part particularly effectively, a further embodiment of the flexible conduit element according to the invention is characterized in that the ring part a) extends radially into a region of the free space and preferably as far as the counterpart; and / or b) has an axial bulge radially at the level of the undercut, in particular a bulge with a rounded outer contour; and / or c) has a cross-section that tapers in the radial direction, in particular in a radially inner section of the ring part; and / or d) has a clear inner diameter that corresponds to the clear inner diameter of the inner component and the clear inner diameter of the connecting part; and / or e) has an axial projection that forms the above-mentioned undercut that is effective in the radial direction.Feature a) enables a particularly large-area effect of the ring part; moreover, the preferred development results in a centering effect for the ring part.

[0045] Feature b) further improves the achievable holding effect for the inner component. The outer contour does not need to be rounded; pointed contours, such as triangular ones, have also proven effective.

[0046] Feature c) ensures particularly firm pressing of the projection when joining the counterpart and connecting part and thus a particularly good holding effect.

[0047] Feature d) ensures that the ring part does not impair the flow through the flexible pipe element.

[0048] Feature e) ensures that the counterpart and connecting part can be designed particularly simply and cost-effectively. In this context, the aforementioned axial projection can have a rounded (concave) transition area to the remaining ring part, and the circumferential projection of the inner component or the outer component can be at least partially designed to be complementary (convex). If, in addition, further sections of the free space are designed to be concave-rounded, the projection of the inner component or the outer component can have a substantially circular cross-section (so-called "O-variant").

[0049] In a further development of the method according to the invention, it can be provided that, together with the connecting part, a continuously circumferential ring part is attached or inserted between a terminal end face of the inner component and the connecting part. This ring part can also be designed as described in detail above. With a corresponding development of the invention, the ring part and counterpart can also be formed in one piece, i.e., as a single component, e.g., by forming or bonding.

[0050] Another embodiment of the flexible conduit element according to the invention is characterized in that the ring part and the connecting part are designed as a single piece. The counterpart and the connecting part are preferably not connected by a material bond, but rather detachably, e.g., by means of a screw connection, as already mentioned above.

[0051] The ring part, in particular, can be designed as a turned part, a deep-drawn part (made of sheet metal), or a cast part. Non-metallic materials can also be used.

[0052] Another development of the flexible line element is characterized in that the ring part has an insertion bevel facing the counterpart around its circumference and the counterpart has a complementary insertion bevel cooperating with the insertion bevel around its circumference.

[0053] The aforementioned lead-in chamfer can also be omitted in another design, resulting in a minimum contact surface for the ring part. To achieve centering and simplify assembly, this minimum contact surface can be designed as a fit.

[0054] The advantage of this design is a significantly improved assembly of the assembly as well as a better sealing effect due to the concentric alignment of the parts to one another.

[0055] Another refinement of the flexible conduit element is characterized by the fact that the counterpart has an insertion bevel on the inside, on its side facing away from the connecting part. This insertion bevel is effective when inserting the inner component (liner) into the bellows. Since the sealing elements of the liner must not be damaged during insertion or pulling through, a chamfer or, alternatively, a rounded edge can be introduced, which is collectively referred to as an insertion bevel. This prevents damage to the sealing elements of the liner (e.g., the aforementioned projections) and ensures easier assembly.

[0056] For this purpose, in a corresponding further development of the method, it can also be provided that in step iii) the inner component is reduced in its outer diameter by means of a suitable device, in particular a mandrel, by displacing the projection radially inwards, and that following step iii) the device is removed, whereby the inner component engages with its projection in the free space.

[0057] In general, the present invention enables the joining of the inner liner (i.e. the inner component), bellows and end piece (connecting part) in the shortest possible installation space, whereby the particular tightness of the connection is to be emphasized.

[0058] According to the invention, the connection between the metal hose and the flexible inner liner can be realized with a variety of materials, e.g. plastic, especially FKM or PTFE, but also with other materials.

[0059] Overall, the present invention, especially within the scope of its relevant developments, achieves particularly good tightness of the connection in the space between the liner (inner component) and the bellows. This is accompanied by security against pull-out under axial tension caused by high forces or creep. Deviating from the previous description, as an alternative or in addition to a radially inner inner component, a radially outer outer component can also be used, which circumferentially surrounds the bellows and at least partially also the counterpart on its outer side. For this to happen, the free space must then be designed accordingly and, in particular, (also) open outwards. The outer component then has a corresponding radial projection towards the inside with which it engages in the free space.

[0060] Otherwise, the outer component may preferably correspond to the inner component, particularly with regard to the choice of material.

[0061] This improves the bellows' buckling behavior (as its primary function). It also provides a fail-safe solution in the event of a bellows leak. A further advantage is the ability to create a clean design with the additional use of contaminated intermediate layers, such as an additional braided sheath.

[0062] In this context, the sequence (radially from inside to outside) bellows-liner-braid is also possible, whereby the liner can be attached outside the bellows and serves to reduce the coefficient of friction or to reduce abrasion on the bellows.

[0063] All welded joints described above can alternatively also be designed as adhesive joints.

[0064] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the drawings. Like reference numerals designate like or at least similarly functioning elements.

[0065] Figure 1 shows a first embodiment of the flexible conduit element according to the invention; Figure 2 shows a detail X from Figure 1;

[0066] Figure 3 shows a second embodiment of the flexible conduit element according to the invention;

[0067] Figure 4 shows a detail X from Figure 3.

[0068] Figure 5 shows a third embodiment of the flexible conduit element according to the invention;

[0069] Figure 6 shows a detail X from Figure 5;

[0070] Figure 7 shows a corresponding detail in a further embodiment of the flexible conduit element according to the invention;

[0071] Figure 8 shows a corresponding detail in yet another embodiment of the flexible conduit element according to the invention;

[0072] Figure 9 shows a corresponding detail in yet another embodiment of the flexible conduit element according to the invention; and

[0073] Figure 10 shows a corresponding detail in another embodiment of the flexible conduit element according to the invention.

[0074] In Figure 1, reference numeral 1 denotes a flexible conduit element according to the invention. This comprises a thin-walled metallic hose or bellows 2, which in this case is annularly corrugated at least in sections along a longitudinal axis L. It is also within the scope of the invention to design the hose / bellows 2 corrugated over its entire length. For simplicity, the term "bellows" will again be used below when referring to bellows or hose. The bellows 2 is preferably made of (stainless) steel.

[0075] At both ends, the bellows 2 has – mirror-image and identical – an annular counterpart 3 made of metal, preferably made of (stainless) steel, the exact shape of which can best be seen in Figure 2. The counterpart 3, also referred to as a "weld-on part" due to its function, is integrally connected to the bellows 2 on its side facing the latter, preferably by welding. On its other side facing away from the bellows 2, the counterpart 3 is also integrally connected to a tubular connecting part 4 made of metal, preferably also made of (stainless) steel. For this purpose, the counterpart 3 has a circumferential (centering) projection 3a on its end face, while the connecting part 4, at reference numeral 4a, has a front-side recess complementary to the projection 3a. In the connected state according to Figures 1 and 2, the projection 3a engages in the recess 4a and centers the counterpart 3 and the connecting part 4 with respect to the longitudinal axis L.A reverse design is also possible.

[0076] In the area of ​​the centering projection 3a and the recess 4a, complementary thread structures for connecting the counterpart 3 and the connecting part 4 can be present, which are not shown in the figures.

[0077] The recess 4a is formed laterally in a radially extending, terminally circumferential projection 4b of the connecting part 4 or in an exclusively radially extending end face 4c of the connecting part 4. In the context of this description, the term "radial" always refers to a direction perpendicular to the aforementioned longitudinal axis L.

[0078] Counterpart 3 and connecting part 4 do not touch each other across their entire face; rather, a free space 5 is formed axially between the end face 4c of the connecting part 4 and the counterpart 3. This free space is continuous in the circumferential direction and opens radially inward. However, it is limited or closed radially outward by the interconnected elements of counterpart 3 and connecting part 4.

[0079] An inner component 6, arranged radially within the bellows 2 and radially spaced therefrom, engages in this free space 5 with a terminal, radial projection 6a. The inner component 6 is preferably made of injection-molded fluororubber (FKM) or another rubber-like, elastic material that is preferably resistant to high-purity demineralized or deionized water, making the conduit element 1 suitable for corresponding applications, e.g., in semiconductor manufacturing. The inner component 6 or the projection 6a is clamped (pressed) between the counterpart 3 and the connecting part 4 and thus held in place.

[0080] To increase the pull-out strength and, in particular, to ensure that no medium from the interior of the line element 1 can penetrate into the area between the bellows 2 and the inner component 6, the counterpart 3 has a radially effective undercut 3b in the area of ​​the free space 5, which is delimited radially inwardly by a web 3c. In the present case, this is also expressed by the fact that the free space 5 has a corresponding undercut, which is to be understood as synonymous. The aforementioned web 3c has a rounded outer contour, while the undercut 3b has a rounded inner contour. The projection 6a of the inner component 6 has an axial bulge 6b, which has a shape in the area of ​​its outer contour that is at least partially complementary to the inner contour of the undercut 3b - partially complementary because the bulge 6b does not completely fill the undercut 3b, as can be seen in particular from Figure 2.This ensures that during pressing, there is no blockage caused by excess, incompressible material (of the inner component 6) in the clearance 5, which could impair the quality of the achievable connection or reduce the inner diameter, potentially resulting in functional limitations. In other words, the material volume of the projection 6a is smaller than the volume of the clearance 5.

[0081] The inner component 6 is otherwise, i.e., apart from the projection 6a, preferably smooth-cylindrical and circular in cross-section. There are other possible shapes for the inner component 6, which are easily realized when designed as an injection-molded part. The inner component 6 extends in the axial direction from the left-side connecting part 4 to the connecting part 4 on the other (right-hand) side of the arrangement. A clear inner diameter ID of the inner component 6 corresponds to the clear inner diameter ID of the connecting parts 4, so that the line element 1 has a constant inner diameter ID overall.

[0082] The connecting part 4 extends radially inward beyond the counterpart and terminates there at the same level as the inner component 6. Conversely, the inner component 6 is also partially arranged radially within the counterpart 3 or extends through it.

[0083] As can be seen in particular from Figure 2, an annular part 7 is inserted on both sides between the respective end face 4c of the connecting part 4 and the inner component 6, the clear inner diameter ID of which corresponds to the aforementioned inner diameters ID of the counterpart 3 and connecting part 4. The annular part 7 has a cross-section that tapers in the radial direction, so that at least in the axial region between the counterpart 3 and the connecting part 4, a wedge-shaped configuration of the annular part 7 is obtained, as can be seen in the section shown. Furthermore, the annular part 7 lies laterally over its entire surface against the end face 4c of the respective connecting part 4.

[0084] In the area where the ring part 7 axially overlaps with the counterpart 3, i.e., in the area of ​​the web 3c and the undercut 3b, the ring part 7 has a fundamentally constant cross-section (a constant thickness) and an axial bulge 7a, specifically a bulge 7a with a rounded outer contour, which is located radially at the level of the undercut 3b and faces it. The outer contour is not limited to round shapes; it can also be pointed, e.g., triangular in section.

[0085] Due to the special geometry of the retaining ring (ring part 7), the end of the liner, i.e., the projection 6a of the inner component 6, is pressed against the counterpart 3, which increases the pull-out strength. Additionally, the "belly of the P," i.e., the bulge 6b engaging the undercut 3b, secures against (further) pull-out under tensile load in the axial direction. The projection 6a with the bulge 6b is approximately P-shaped overall.

[0086] The second embodiment of the flexible line element 1 according to Figures 3 and 4 corresponds essentially completely to Figures 1 and 2, with the exception of a (significantly smaller) wall thickness WD1 of the inner component 6, so that it will not be discussed further here.

[0087] Another difference lies in the wall thickness WD2 of the connecting part 4 in the region of its axial, free end: as can be seen in particular from Figure 4, the wall thickness WD2 is initially relatively thick and then decreases slightly in the axial direction, see Figure 3, whereby the clear inner diameter also expands in the manner of an insertion bevel up to a maximum inner diameter ID'. In the embodiment according to Figures 1 and 2, however, the connecting part 4 is designed with significantly thinner walls in the aforementioned section; moreover, the clear inner diameter ID, as already mentioned, does not change.

[0088] The second embodiment of the flexible line element 1 according to Figures 3 and 4 is not limited to the described embodiment with an insertion bevel, which can also be omitted. Furthermore, such a bevel can also be provided in the embodiment according to Figures 1 and 2. In the embodiment shown, the slight bevel (also) serves to adapt the inner diameter ID of the inner component 6 to the dimensions of the cylindrical pipe end (connecting part 4) for connecting additional line elements specified by the customer (not shown). The smallest possible (form) bevel was selected in order to keep pressure losses and FIV low.

[0089] In the third embodiment of the flexible conduit element 1 according to Figures 5 and 6, the (introduction) slope is configured in the opposite direction, which will not be discussed further here. The flexible conduit elements 1 according to Figures 1 to 4 can also be configured accordingly. The inner component 6 according to Figures 5 and 6 corresponds to the design in Figures 3 and 4, with the exception of the projections 6a, which will be discussed in more detail below.

[0090] Figure 6 shows in detail the design of the flexible conduit element 1, which differs from Figures 5 and 6, in particular in the area of ​​the free space 5, the projections 6a, and the annular part 7. The latter has an axial projection at reference numeral 7b, which forms a radially effective undercut 7c (corresponding to the undercut 3b according to Figures 2 and 4) in the area of ​​the free space 5 and, in this respect, is essentially functionally equivalent to the web 3c (cf. Figures 2 and 4). In the present case, this is again expressed by the fact that the free space 5 has a corresponding undercut, which is to be understood as synonymous.

[0091] The axial projection 7b of the ring part 7 merges into the remaining ring part 7 in a rounded or concave manner, as can be clearly seen in Figure 6. The counterpart 3 has a corresponding, concave-rounded design on its inner side delimiting the free space 5, so that the free space 5 formed between the counterpart 3 and the connecting part 4 or ring part 7 has an approximately circular cross-section. Accordingly, the inner component 6 has a substantially convex-circular cross-section in the region of its projections 6a. The illustrated design of the flexible conduit element 1 is therefore also referred to as an "O-variant" because the projections 6a are designed like O-rings.

[0092] Figures 7 to 10 show detailed views of further embodiments of the flexible conduit element 1, each in one end region; the other end can be of a similar design. Only the respective special features will be discussed in more detail below, provided they differ from the previously explained embodiments.

[0093] According to Figure 7, the inner component 6 has a further radially outer circumferential projection 6c, which bears against the counterpart 3 on a side facing away from the connecting part 4. The further projection 6c has a triangular or sawtooth-shaped cross-section. The side surface 6d bearing against the counterpart 3 extends in a purely radial direction. Alternatively, the inner component 6 can be stated to have a radially outer groove (not designated), into which the counterpart 3 engages in a form-fitting manner with a corresponding rib (also not designated).

[0094] According to Figure 8, the inner component 6 also has a further radially outer circumferential projection 6c, which is also triangular in cross section and which engages in a groove 3d arranged on an inner side of the counterpart 3, which is also (complementarily) triangular in cross section.

[0095] According to Figure 9, the counterpart 3 has, on its side facing away from the connecting part 4, a circumferential insertion bevel 3e on the inside in order not to damage the inner component 6 during joining.

[0096] In all Figures 7 to 9, the ring part 7 has a radially outwardly arranged insertion bevel 7d extending circumferentially toward the counterpart 3. The counterpart 3 has a complementary insertion bevel 3f extending circumferentially and interacting with the insertion bevel 7d.

[0097] According to Figure 10, the ring part 7 can axially overlap the inner component 6 in the region of the projection 6a.

[0098] Any combination of the features shown in Figures 7 to 10 is also possible, provided that it is technically feasible and reasonable.

[0099] To produce the flexible conduit element 1 according to Figures 1 to 10, the bellows 2 and the counterparts 3 are first connected, in particular welded together. Then, the inner component 6 is inserted (under suitable deformation to specifically reduce the outer diameter), whereby in particular the projections 6a are brought into engagement with the undercuts 3b. The ring parts 7 are then attached together with the connecting parts 4 and axially pressed against the counterparts 3 or with the inner component 6 and the projections 6a. Finally, the counterparts 3 and connecting parts 4 are permanently connected in pairs, in particular welded together. The ring parts 7 can be fixed to the associated connecting parts 4 during or before joining in order to facilitate handling, unless a one-piece design is present.

Claims

Claims 1. A flexible conduit element (1), comprising: a metallic corrugated hose section or bellows (2); at at least one end of the corrugated hose section or bellows (2), a tubular connecting part (4) which is connected to the corrugated hose section or bellows (2) via an annular counterpart (3), wherein the counterpart (3) is integrally connected to the corrugated hose section or bellows (2) on one side and to the connecting part (4) on the other side; a tubular inner component (6) made of a plastic, in particular an elastomer material, preferably fluororubber, accommodated in the corrugated hose section or bellows (2) and in the counterpart (3), and / or a tubular outer component made of a plastic, in particular an elastomer material, preferably fluororubber, surrounding the corrugated hose section or bellows (2) and the counterpart (3);characterized in that a continuous circumferential free space (5) is formed axially between the connecting part (4) and the counterpart (3); and the inner component (6) and / or the outer component has, in a region of said end, a circumferential projection (6a) which extends radially outwards with respect to a longitudinal axis (L) of the line element (1) in the case of the inner component (6) and radially inwards in the case of the outer component, and with which the inner component (6) and / or the outer component engages in the free space (5).

2. Flexible conduit element (1) according to claim 1, characterized in that the free space (5) has an undercut (3b, 7c) effective in the radial direction.

3. Flexible conduit element (1) according to claim 2, characterized in that the inner component (6) has on the projection (6a) a bulge (6b) in the axial direction, which bulge engages with the undercut (3b).

4. Flexible conduit element (1) according to claim 2 or 3, characterized in that the undercut (3b) is formed in the counterpart (3).

5. Flexible conduit element (1) according to one of claims 2 to 4, characterized in that the undercut (3b, 7c) has a rounded inner contour.

6. Flexible conduit element (1) according to one of claims 2 to 5, characterized in that the bulge (6b) has an outer contour complementary to the undercut (3b).

7. Flexible conduit element (1) according to one of claims 2 to 6, characterized in that a web (3c) delimiting the undercut (3b) in the radial direction inwards has a rounded outer contour.

8. Flexible conduit element (1) according to one of claims 1 to 7, characterized in that the projection (6a) fills the free space (5) and in particular the undercut (3b) according to claim 2 only to a fraction.

9. Flexible conduit element (1) according to one of claims 1 to 8, characterized in that the inner component (6) is arranged at a clear distance in the radial direction from the corrugated hose section or bellows (2).

10. Flexible conduit element (1) according to one of claims 1 to 9, characterized in that a clear inner diameter (ID) of the inner component (6) is equal to a minimum clear inner diameter (ID) of the connecting part (4) which is preferably widened towards its free end.

11. Flexible conduit element (1) according to one of claims 1 to 10, characterized in that the inner component (6) has a radially outer groove into which the counterpart (3) engages.

12. Flexible conduit element (1) according to one of claims 1 to 11, characterized in that the inner component (6) has a further radially outer circumferential projection (6c) which rests on the counterpart (3) on a side facing away from the connecting part (4) or which engages in a groove (3d) arranged on an inner side of the counterpart (3), wherein in particular the further projection (6c) and the groove (3d) are triangular or semicircular in cross section.

13. Flexible conduit element (1) according to one of claims 1 to 12, characterized in that the counterpart (3) has an axial centering projection (3a) at its end and the connecting part (4) has a complementary recess (4a) on its side facing the counterpart (3), wherein the counterpart (3) engages with the centering projection (3a) in the recess (4a), or vice versa.

14. Flexible conduit element (1) according to claim 13, characterized in that complementary thread structures are present in the region of the centering projection (3a) and the recess (4a).

15. Flexible conduit element (1) according to one of claims 1 to 14, characterized in that the connecting part (4) is flat on an end face (4c) facing the free space (5), wherein the end face (4c) preferably extends exclusively in the radial direction.

16. Flexible conduit element (1) according to one of claims 1 to 13, characterized in that a continuously circumferential ring part (7) is arranged between a terminal end face of the inner component (6) and the connecting part (4), in particular on its end face (4c) according to claim 15.

17. Flexible conduit element (1) according to claim 16, characterized in that the annular part (7) a) extends radially into a region of the free space (5) and preferably as far as the counterpart (3); and / or b) has an axial bulge (7a) radially at the level of the undercut (3b), in particular a bulge (7a) with a rounded outer contour; and / or c) has a cross-section tapering in the radial direction, in particular in a radially inner section of the annular part (7); and / or d) has a clear inner diameter (ID) that corresponds to the clear inner diameter (ID) of the inner component (6) and the minimum clear inner diameter (ID) of the connecting part (4) according to claim 10; and / or e) has an axial projection that forms the undercut (7c) effective in the radial direction according to claim 2.

18. Flexible conduit element (1) according to claim 16 or 17, characterized in that the ring part (7) has an insertion bevel (7d) facing the counterpart (3) around its circumference and the counterpart (3) has a complementary insertion bevel (3f) cooperating with the insertion bevel (7d).

19. Flexible conduit element (1) according to one of claims 1 to 18, characterized in that the counterpart (3) has an insertion bevel (3e) on its inside on its side facing away from the connecting part (4).

20. A method for producing a flexible conduit element (1), in particular the flexible conduit element (1) according to one of the preceding claims, comprising: i) providing a metallic corrugated hose section or bellows (2); ii) materially bonding an annular counterpart (3) to at least one end of the corrugated hose section or bellows (2); iii) introducing a tubular inner component (6), in particular made of an elastomer material, into the corrugated hose section or bellows (2) and into the counterpart (3), in particular upon radial compression of the inner component (6), which inner component has, in a region of said end, a circumferential projection (6a) which extends radially outwards with respect to a longitudinal axis (L) of the conduit element (1);iv) axially attaching a tubular connecting part (4) to the counterpart (3) to form a continuous, circumferential free space (5) axially between the connecting part (4) and the counterpart (3), so that the inner component (6) engages with its projection (6a) in the free space (5); v) permanently, preferably by means of a material connection, the connecting part (4) and the counterpart (5) to be clamped between the connecting part (4) and the counterpart (3) in a region of the free space (5); 21. Method according to claim 20, characterized in that, together with the connecting part (4), a continuously circumferential ring part (7) is inserted between a terminal end face of the inner component (6) and the connecting part (4), which ring part (7) is preferably further designed according to the relevant features of claim 17. TI 22. Method according to claim 20 or 21, characterized in that in step iii) the inner component (6) is reduced in its outer diameter by means of a suitable device, in particular a mandrel, by displacing the projection (6a) radially inwards, and that following step iii) the device is removed, whereby the inner component (6) engages with its projection (6a) in the free space (5).

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