Flexible hose, in particular vacuum-cleaner hose, profile and method for producing such a hose, and die for extruding such a profile

Abstract

A flexible hose (10) has a wall (12) which is formed from a profile (16) wound helically about a longitudinal axis (14) and which, with an inner side (18), delimits a cavity (20) for conducting media. For this purpose, the profile has a plurality of surface-area portions (22, 24, 26) in a media-exposed position, while adjacent turns of the profile (16) are connected to one another in a media-tight manner. At least on the inner side of the wall, the turns form a profiling (30) which – as seen in section along the longitudinal axis - has a wave shape comprising elevations (32) and depressions (34). At least one of the aforementioned surface-area portions is provided with a microstructure (36) which runs helically with the wound profile about the longitudinal axis and imparts a fine profile to this otherwise smooth surface-area portion such that, in the region of the microstructure, there is a variation in the wall thickness (W) of the wall in a direction normal to the respective surface-area portion of the profile. The invention further proposes a hose profile of this kind, a method for producing such a hose, and a die which can be used to extrude a hose profile of this kind.

Description

[0001] Flexible hose, especially vacuum cleaner hose, profile and method for manufacturing such a hose and nozzle

[0002] TO EXTRUD SUCH A PROFILE

[0003] TECHNICAL AREA

[0004] The present invention relates generally to a flexible hose according to the preamble of claim 1, a profile for manufacturing a flexible hose according to the preamble of claim 9, a method for manufacturing a flexible hose according to the preamble of claim 13, and a nozzle for extruding a profile for manufacturing a flexible hose according to the preamble of claim 15. In particular, the invention relates to a flexible vacuum cleaner hose of the type used in large quantities in industrial settings, in trade, and in private households, together with semi-finished products suitable for continuous production of such a hose, and to its manufacture, especially in large quantities, including suitable tools for this purpose.

[0005] BACKGROUND OF THE INVENTION AND STATE OF THE ART

[0006] From the patent application DE 10 2021 003 907 A1, which forms the preamble of claims 1 and 9, a flexible hose, in particular a vacuum cleaner hose, is known which, as can be seen, for example, in Fig. 3 of this patent application, has a wall of defined thickness that defines a cavity for conveying media on its inner side and is formed from a profile wound helically around a longitudinal axis. For this purpose, the profile has a plurality of surface sections that are smooth when viewed from close range and are exposed to the media; that is, surface sections that ultimately define the cavity inside the hose wound from the profile through which the media are conveyed, or which are swept over or "wetted" by the conveyed media.Adjacent turns of the helically wound profile are connected to each other in a media-tight manner, whereby the turns, at least on the inside of the wall, form a profiling overall "macrostructurally" which, viewed in cross-section along the longitudinal axis of the hose, has a wave shape with elevations and depressions.

[0007] More precisely, a profile is used to manufacture this known flexible hose. This profile is first extruded from a thermoplastic material and then helically wound around a longitudinal axis to define the cavity for conveying the medium within the hose. The known profile comprises a first profile section designed to form the recesses of the profiled wall of the hose, which has a defined wall thickness, and a second profile section integrally connected to the first profile section, designed to form the raised sections of the profiled wall of the hose, which has a defined wall thickness.The first profile area and the second profile area are adapted to interlock during the helical winding of the hose in such a way that the second profile area of ​​one turn of the profile overlaps the first profile area of ​​an adjacent turn of the profile, and the said surface sections remain in an exposed position with respect to the conveyed media on the first and second profile areas.

[0008] Such hoses can optionally be equipped to dissipate an electrostatic charge. For example, German patent DE 20 2009 016 596 Ul specifies a coiled suction hose with at least one electrical conductor for dissipating electrostatic charge, which extends essentially over the coil length of the suction hose and has a width that is at most equal to the channel width of the suction hose.The production of such a hose typically employs a method which, in accordance with the preamble of claim 13, briefly comprises the following main process steps: a) extruding a profile from a thermoplastic material using a die having the features of the preamble of claim 15, in particular an extrusion gap whose gap cross-section essentially corresponds to the cross-section of the produced profile; b) calibrating the extruded, still plastically deformable profile to finely shape a geometrically defined profile cross-section; c) cooling the calibrated profile to fix the geometrically defined profile cross-section; d) winding the cooled profile to form the hose; and e) finishing the wound hose by (among other things) cutting the endlessly wound hose to length.

[0009] Vacuum cleaner hoses wound from a plastic profile have been used for many years, for example, in higher-end upright vacuum cleaners for household use. However, in this market segment, several competing products – some of them hoseless – such as cyclone vacuums, cordless stick vacuums, and robotic vacuums, have become established in recent years. At the same time, regulatory authorities have significantly limited the permissible electrical power for such vacuum cleaners in order to save energy. Manufacturers have recently responded to this pressure to innovate with more efficient vacuum cleaner designs that provide greater suction power with the same electrical power. This results, in particular, in a higher airflow rate and greater flow velocities in the suction hose.

[0010] However, the increased flow velocity in the suction hose means that even hose designs that have proven themselves on the market for years can produce unwanted noises when used in combination with these newly developed vacuum cleaner models. For example, whistling noises can occur when the vacuum cleaner is operated at its highest suction power with a nozzle on the suction hose that, like a throttle valve, prevents a predominantly axial flow through the hose, while the suction hose simultaneously undergoes significant deformation along its length, for example, because it is placed in a tight loop.

[0011] The prior art contains numerous proposals for addressing the undesirable noise generated by a suction hose. For example, German patent DE 1 628 641 B discloses a vacuum cleaner hose consisting of an apparently bias-shaped corrugated hose with a connector. To prevent whistling noises, it is specifically proposed to arrange axially offset projections 2e on an inner surface of the connector 2 (see in particular Figures 7a and 7b of this patent).

[0012] A flexible vacuum cleaner hose made of a plastic material by an extrusion blow molding process is also known from US patent 4,756,045. The hose disclosed therein has an inner surface (see especially Fig. 4 of this patent) comprising alternating protrusions and indentations, with indentations of greater depth and / or width alternating with indentations of lesser depth and / or width. These alternating waves provide the hose with an uneven inner surface, which is intended to reduce whistling by interrupting the flow of air. A disadvantage of this solution to the problem of unwanted whistling is seen in later prior art as the fact that the uneven inner surface results in higher internal air resistance, leading to a loss of air pressure along the waves of the inner surface and thus to a loss of the hose's capacity.Another approach to "combating" unwanted noise is described in EP 0 399 433 Bl. This prior art describes a suction hose for a vacuum cleaner with a sound absorption system in the handle (see Figures 1 to 3 of this document). This system comprises a hollow cylindrical body with sound-absorbing holes on a section extending in the air intake direction, a cover attached to the outer surface of this cylindrical body to cover this section, and a sound-absorbing material arranged between the cover and this section, the section corresponding to a strip extending along the sound-generating surface of the cylindrical body. Such solutions, however, involve considerable technical effort and are therefore costly.

[0013] Furthermore, German patent DE 92 10 126 Ul discloses a flexible hose with a corrugated wall, which has an inner surface with alternating bulging and corrugated sections (see Figures 1 and 2 of this patent) to reduce hose whistling. This hose can be made of a plastic material – apparently blow-molded – or metal, and it can be parallel-corrugated or spirally corrugated. A special feature is that the bulging sections are to be at least twice the size of the opening between the corrugated sections. The bulging sections can also be flat or straight (see Figure 2 of this patent), which reduces the excitation frequency and the energy of their pressure fluctuations, thus further improving the flow characteristics.

[0014] Furthermore, a blow-molded suction hose is known from EP 1 099 894 Bl (see Figures 1 and 2 of this document), in which a special geometry of the projections and recesses located on the inner surface of the hose is proposed to eliminate disturbing whistling noises and to improve flow resistance when air flows through it. In particular, higher outer projections are intended to extend further from the outer surface and alternate with lower outer projections that extend less far from the outer surface. Moreover, a specific ratio between the extent of the projections in the flow direction and the extent of the recesses in the flow direction is considered advantageous.

[0015] Furthermore, German patent DE 10 2005 018 373 discloses an openly wound, flexible suction hose for a vacuum cleaner with circumferential bellows corrugations (see Figures 1 and 2 of this patent) which form successive depressions and protrusions on the inside of the hose in the direction of flow. To improve the flow characteristics of this suction hose, it is proposed that at least one planar element extending substantially circumferentially and in the direction of flow be arranged on the inside of the hose, at least partially covering the depressions. A problem with this prior art is certainly that the proposed hose cannot be used in a direction-independent manner because the planar elements must not be raised by the flow within the hose; rather, they must be pressed into their position covering the depressions by the flow.

[0016] In publication EP 1 969 987 Al, a wound, flexible vacuum cleaner hose is also disclosed, designed to reduce whistling noises within the hose. For this purpose, an air barrier is provided on the inside of the wall to close each of the inner grooves (see Fig. 4 of this publication). This air barrier is formed, for example, by a first closing leg on a first side of the winding profile and a second closing leg on an opposite, second side of the winding profile, which overlap at least partially when wound. This is intended to block the access of air and / or dust particles to the inner grooves and reduce the unwanted whistling.However, this solution to the problem of unwanted whistling is later said to have the disadvantage that, due to the partial overlap of the sealing legs, an uneven surface is formed, which is said to increase the flow resistance for the air and / or dust particles. Furthermore, this hose also appears to be unsuitable for use in any direction.

[0017] From US 7,559,342 B2, a rewound suction hose is known (see Fig. 4 of this document), with a multitude of folds which have inlet sections on the inside of the hose that are suitably designed, i.e., inclined opposite to the main flow direction, to reduce noise. The problem of the directional dependence of the hose's internal geometry also exists in this prior art.

[0018] Furthermore, the related publications EP 2 382 413 Bl and DE 20 2010 018 392 Ul disclose a flexible hose comprising a corrugated wall formed by spirally winding successive profile sections, the outer surface of which has a plurality of successive external projections and grooves, and the inner surface of which has a plurality of internal projections and grooves. Each internal projection and each internal groove is arranged next to a corresponding external groove and a corresponding external projection on the outer surface.The corrugated wall further comprises a plurality of barriers for closing each of the plurality of inner and / or outer grooves, each barrier having a first closing leg of a first profile part and a second closing leg of a second, adjacent profile part. The first and second closing legs are directed towards each other and partially overlap in the longitudinal direction of the hose in a manner that allows them to be displaced relative to each other when the hose is bent inwards or outwards. The first and second closing legs have a coordinated design such that at least one of the first and second closing legs of each barrier is wedge-shaped, forming a substantially smooth inner and / or outer surface.In this state of the art, the whistling of the hose is to be reduced precisely by giving the first and second locking jaws an essentially smooth inner surface. However, the sliding of the first and second locking jaws in this state of the art makes bending the hose more difficult, thus "at the expense" of the hose's flexibility.

[0019] Furthermore, a flexible hose is known from publication JP 2012-097905 A, which is optimized with regard to its bending behavior and the avoidance of airflow resonance noise. This hose is wound spirally from a ribbon-like body, with the overlapping, adjacent parts of the ribbon-like body being bonded and connected to one another with an adhesive. The ribbon-like body has an essentially S-shaped cross-section, with the two end parts forming the overlapping section in cross-section. Between the two end parts, in cross-section of the hose, is a free hose section consisting of a first part rising with respect to the hose axis and a second part essentially parallel to the hose axis. The second part is connected to the overlapping section and to the first part, respectively, via an arc-shaped section.The second part can have a wave-shaped cross-section with constant wall thickness, as shown in Figures 4 and 5 of this publication.

[0020] Furthermore, German patent DE 10 2011 084 195 describes a hose assembly, particularly for use as a suction hose on a vacuum cleaner, in which a barrier in the form of a compressible foam filling the trough is provided in the area of ​​the inner corrugations for pneumatic and / or hydraulic smoothing of the hose assembly (see Fig. 2b therein), and the hose assembly consists of a helically wound profile strand. The hose assembly wound from this profile strand filled with foam serves to prevent the accumulation of dust and the like in the corrugation trough.

[0021] Finally, German patent DE 203 05 574 discloses a flexible conduit element, particularly for exhaust pipes of internal combustion engines in motor vehicles, which has at least one bellows and at least one coiled hose with overlapping turns arranged coaxially within the bellows. In this prior art, the coiled hose is held radially by the bellows, either directly or indirectly. Particularly if the conduit element does not have spacers between the coiled hose and the bellows, a preferred embodiment (see Fig. 13c in this prior art) may provide that the band forming the coiled hose has a bulge or projection in its radially outer axial section in order to ensure contact with the surrounding bellows along a defined (axis-parallel) line. Due to the lack of play at this point, the coiled hose, which is not inherently stable, flexes during operation, i.e.,With the engine running, do not move it back and forth against the bellows to avoid noise.

[0022] PROOF OF THE INDUSTRY Starting from the prior art according to, for example, German patent DE 10 2021 003 907, the invention is based on the objective of providing an alternative flexible hose, in particular a vacuum cleaner hose, wound from a plastic profile, as well as a suitable profile for this purpose, which addresses the problems discussed above in relation to the prior art and in particular has optimized noise characteristics without whistling and with the lowest possible background noise even at high media flow rates. The object of the invention further includes the specification of a method for manufacturing such a flexible hose, which enables the simplest, fastest, most cost-effective and in particular process-reliable production of the hose, as well as the creation of an extrusion die for the profile, which can be used in particular in the course of this method.

[0023] PRESENTATION OF THE INVENTION

[0024] These problems are solved by a flexible hose, in particular a vacuum cleaner hose, with the features of claim 1, a profile extruded from a thermoplastic material for producing a flexible hose, with the features of claim 9, a method for producing a flexible hose for conveying media, with the process steps of claim 13, or a nozzle for extruding a profile from a thermoplastic material for producing a flexible hose, with the features of claim 15. Advantageous embodiments of the invention are the subject of the dependent claims.

[0025] According to a first, product-related aspect of the invention, a flexible hose, in particular a vacuum cleaner hose, comprises a wall of defined wall thickness formed from a profile wound helically around a longitudinal axis, which on its inner side defines a cavity for conveying media, for which the profile has a plurality of surface sections in a position exposed to the media and adjacent turns of the profile are connected to each other in a media-tight manner, wherein the turns form a profile at least on the inner side of the wall which, viewed in section along the longitudinal axis of the hose, has a wave shape with elevations and depressions;According to the invention, at least one of the surface sections of the profile arranged in a position exposed to the media is provided with a microstructure which spirals around the longitudinal axis of the wound profile and finely profiles this otherwise smooth surface section, so that in the area of ​​the microstructure the wall thickness of the wall varies in a direction normal to the respective surface section of the profile.

[0026] In the context of the present invention, a "media-exposed position" of the surface sections in question on the profile means that the surface section in question of the wall formed by the profile is located at a point on the inside of the hose that is either directly swept over by the conveyed medium or is at least in contact or communicates with the conveyed medium, so that waves propagating in the conveyed medium can occur on the respective surface section.

[0027] In the context of the present invention, "microstructure" on or in the relevant surface section(s) of the profile means, firstly, that this structure finely profiles the respective surface section, i.e., is significantly smaller than the wave-like (macro) profiling on the inside of the wall with its protrusions and depressions. In particular, in the area of ​​the microstructure, the wall thickness of the profile varies in a direction normal to the respective surface section of the profile, which is in any case located in a position exposed to the media.

[0028] Investigations carried out by the inventors have shown that such fine profiling on at least one of the surface sections exposed to the conveyed media on the coarsely corrugated inner wall of the wound hose, which interrupts or breaks up the smoothness of the respective surface section, thus leading to a certain unevenness or roughness of the corresponding surface section, yields positive results with regard to the reduction, suppression, or prevention of unwanted noise. In particular, with such a design of the hose's inner surface, the aforementioned whistling or unwanted resonance effects at certain frequencies can be eliminated, even and especially when the correspondingly designed hose is operated in a system with pipe and nozzle, with high flow rates, e.g., 35 liters per second or higher, and with strong bends or cross-sectional deformations of the hose.

[0029] Advantageously, this does not require any elaborate measures, such as those provided for in the prior art described above, to "smooth out" the wave pattern on the inside of the hose wall or to close or cover the recesses of the (macro) profiling of the hose wall. The positive effects of the microstructure according to the invention on noise generation in or on the hose therefore do not require any auxiliary materials in the hose that could undesirably increase the weight of the hose, restrict its flexibility, or lead to "dust traps" in the hose due to the closure of the inner recesses.

[0030] The design of the hose according to the invention thus advantageously also enables the hose to be used independently of the suction direction, which also allows the production of double-conical hoses, with the associated cost advantages, because in production it is not necessary to work with so-called "sacrificial hose pieces" between hose sections usable for the end product, which cannot be used as an end product.

[0031] Since the measures according to the invention are applied to the hose profile to be wound, more precisely to at least one surface section thereof, in / on which the microstructure is to be formed, and since the finished wound hose does not need to be processed or treated in any way, these measures can be implemented in a very process-reliable manner during the manufacture of the hose.

[0032] In a preferred embodiment of the flexible hose, the profile, viewed in a profile cross-section, has a first profile area and a second profile area integrally connected to the first profile area, wherein the first profile area of ​​the wound profile forms the depressions of the profiling of the wall, while the second profile area of ​​the wound profile forms the elevations of the profiling of the wall, and wherein the second profile area of ​​a turn of the profile is media-tightly connected to the first profile area of ​​an adjacent turn of the profile.

[0033] Hoses designed in this way advantageously possess a very regular, visually appealing appearance due to the ease of their winding and can be wound reliably in a robust winding process. Alternatively, the measures according to the invention (microstructure) can also be implemented on profiles that are wound into a two- (or more) twisted hose, as is known in principle, for example, from US 7,559,342 B2, and which accordingly have (at least) four consecutive profile areas for forming two raised and recessed areas per winding pass.

[0034] In a suitable embodiment of the flexible hose, viewed in a cross-section of the profile wound to form the hose, the first and second profile sections can interlock in such a way that the second profile section of one turn of the profile overlaps the first profile section of an adjacent turn of the profile, while the surface sections of the first and second profile sections otherwise remain exposed to the media on the inside of the wall. With this winding technique, a whole series of surface sections thus advantageously remain on which the microstructure according to the invention can be formed in order to influence the noise behavior of the hose.

[0035] Preferably, the second profile area of ​​a turn of the profile and the first profile area of ​​an adjacent turn of the profile are connected to each other in the area of ​​mutual overlap, which not only creates a reliably media-tight connection, but can also be designed in an aesthetically pleasing way.

[0036] Furthermore, with regard to particularly good noise characteristics, especially low background noise of the hose, it is preferred if the second profile section is provided with a thickening at its end. Viewed in cross-section of the profile wound into the hose, the thickening of the second profile section of a turn of the profile reduces the volume of the depression in the wall profile formed by the first profile section of an adjacent turn of the profile. This leads, in particular, to a certain disruption of the wave symmetry of the wall profile, in addition to influencing the internal damping through an increase in mass in this profile section. This is considered positive with regard to preventing the generation of unwanted noise – although it necessitates the use of more plastic material for forming the profile, and hoses designed in this way therefore also have a certain additional weight.

[0037] In particular, to obtain a hose that is as light and flexible as possible yet sufficiently stable, it is further preferred if, viewed in the profile cross-section, the first profile area is essentially U-shaped, with a first rib at the beginning of the profile cross-section and a second rib opposite the first rib, which is connected to the first rib via an arc section, while the second profile area is essentially angled or L-shaped, with a bottom section adjoining the second rib of the first profile area and a third rib angled away from it at the end of the profile cross-section, wherein the microstructure on the side facing the cavity is formed on a surface section of the second rib and / or a surface section of the bottom section and / or a surface section of the third rib.

[0038] In this design of the hose, the curved section advantageously ensures good flexibility of the hose, the essentially flat bottom section advantageously ensures good flow characteristics in the hose, and the ribs advantageously ensure sufficiently high wall stability. At the same time, the application of the microstructure according to the invention to the profile is readily possible without negatively affecting the other properties of the profile.

[0039] Furthermore, it is preferred that, viewed in cross-section of the profile wound into a hose, the third web of a turn of the profile overlaps the first web of an adjacent turn of the profile and is bonded to it in a media-tight manner in the area of ​​the mutual overlap. This represents a proven joining technique for the continuous production of wound hoses; however, as an alternative, it would also be conceivable to weld the webs together in the area of ​​the overlap without the application of adhesive.

[0040] As mentioned above, the measures according to the invention (microstructure on certain profile surfaces) advantageously allow preferred embodiments of the flexible hose to be manufactured, adapted to the respective hose use, in which the profile is wound along a helix around the longitudinal axis to the wall of the hose with a cylindrical, conical or doubly conical basic shape.

[0041] According to a second, product-related aspect of the invention, a profile extruded from a thermoplastic material and capable of being helically wound around a longitudinal axis to produce a flexible hose for defining a cavity for conveying media comprises a first profile area designed to form recesses in a profiled wall of the hose of a defined wall thickness, and a second profile area integrally adjoining the first profile area, designed to form protrusions in the profiled wall of the hose of a defined wall thickness, wherein the first profile area and the second profile area are adapted to interlock during helical winding of the hose.that the second profile area of ​​a turn of the profile overlaps the first profile area of ​​an adjacent turn of the profile and surface sections remain in a position exposed to the media at the first and second profile areas; according to the invention, at least one of the surface sections of the first and second profile areas remaining in a position exposed to the media is provided with a microstructure which finely profiles this otherwise smooth surface section, so that in the area of ​​the microstructure the wall thickness of the wall varies in a direction normal to the respective surface section of the profile.

[0042] As already mentioned, such a microstructured, noise-optimized profile can be easily mass-produced in a reliable manner. If the profile is not wound into a tube immediately after extrusion, it can also be manufactured "on a roll" first, before being wound into a tube at a later time and possibly at a different location.

[0043] In a specific, preferred embodiment of the flexible hose or the profile therefor, the microstructure on at least one surface section of the profile that is located or remains in a position exposed to the media can comprise at least one rib and / or at least one groove and / or a tooth and / or knurled embossing. A "rib" is synonymous with a raised surface modification, while a "groove" is synonymous with a recessed surface modification. The tooth and knurled embossings each represent a fine embossing of the surface in question on the profile, which is produced with the aid of a geometrically defined shape on the respective embossing tool.

[0044] The aforementioned fine geometries of the microstructure can be advantageously and reliably generated on the profile before it is wound into a tube, as will be explained later. A corresponding microstructure could, of course, also be generated with a suitable steel brush, a needle roller, or the like, which is driven, for example, by rotating it or—similar to a honing process—by moving it translationally back and forth over the corresponding surface section of the profile, possibly even after the profile has been wound into a tube. However, all of this is more difficult to implement reliably, which is why such alternatives are less preferred.

[0045] It is further preferred if, on the flexible tube or profile, the at least one rib of the microstructure, viewed in the profile cross-section, has a rectangular basic shape with two opposing side surfaces and a free end surface, wherein transitions between the two side surfaces and the free end surface are rounded, and / or the at least one groove of the microstructure, viewed in the profile cross-section, has a rectangular basic shape with two opposing flanks and a bottom surface, wherein transitions between the two flanks and the bottom surface are rounded. Such fine geometries of the microstructure can be very well formed during the extrusion of the profile from the plastic material in / on the corresponding surface section of the profile.

[0046] A die for an extrusion process to produce such a profile with a rib or groove is particularly easy to manufacture or adapt. The negative contour of the rib, for example, can be easily added to the extrusion gap, e.g., by wire EDM to create a groove. As alternatives to the aforementioned geometries for the rib or groove, other cross-sectional shapes are of course conceivable, such as triangular, semicircular, square, polygonal, each with or without edge rounding, etc., which lead to a corresponding break or interruption of the respective surface section of the profile. However, such cross-sectional shapes are usually more difficult to form on the profile or tool and are therefore less preferred.

[0047] In a specific, preferred embodiment of such fine geometries for the microstructure, the height of at least one rib of the microstructure, relative to the average wall thickness of the profile, can be in a range between 1:100 and 1:2, and / or the width of at least one rib of the microstructure, relative to the average wall thickness of the profile, can be in a range between 1:20 and 2:1, and / or the depth of at least one groove of the microstructure, relative to the average wall thickness of the profile, can be in a range between 1:100 and 1:2, and / or the width of at least one groove of the microstructure, relative to the average wall thickness of the profile, can be in a range between 1:20 and 2:1. When specifically designing the ribs and grooves, it would of course also be necessary to consider any potential loss of suction power associated with such fine geometries on the hose.For each specific application of the hose, a specialist would ultimately have to find a compromise in the design of the hose's microstructure between optimizing the hose's noise characteristics and minimizing pressure loss along its length. This can, of course, also involve adjusting the distribution or pattern (symmetrical / asymmetrical) of the grooves or ridges on the respective section of the profile.

[0048] According to a third aspect of the invention, which generally relates to a manufacturing method for wound hoses, a method for producing a flexible hose for conveying media comprises the following main process steps, carried out in the specified order: a) extruding a profile from a thermoplastic material, comprising, in profile cross-section, first and second profile areas, which are formed to create internal depressions and internal protrusions of a profiled wall of the hose of defined wall thickness; b) calibrating the extruded, still plastically deformable profile to finely shape a geometrically defined profile cross-section; c) cooling the calibrated profile to fix the geometrically defined profile cross-section;d) Winding the cooled profile to form the hose, wherein the first and second profile sections are helically interlocked and joined together in a media-tight manner, leaving surface sections exposed to the media; e) Assembling the wound hose; according to the invention, in one or more of the main process steps a) to d), a microstructure is formed at least on one of the surface sections of the first and second profile sections, which finely profiles this otherwise smooth surface section, so that in the area of ​​the microstructure the wall thickness varies in a direction normal to the respective surface section of the profile.

[0049] As already mentioned, the microstructure according to the invention can thus be formed on the profile in a very process-reliable manner before the hose is ultimately created.

[0050] Accordingly, in preferred process embodiments, it is possible that in the main process step a) during extrusion of the profile, at least one rib and / or at least one groove is formed as part of the microstructure on at least one of the surface sections of the first and second profile areas; and / or in the main process step b) during calibration of the extruded, still plastically formable profile, a molded embossing, preferably a tooth or knurled embossing, is formed as part of the microstructure on at least one of the surface sections of the first and second profile areas; and / or in at least one of the main process steps c) of cooling the calibrated profile and d) of winding the cooled profile, a molded embossing, preferably a tooth or knurled embossing, is formed as part of the microstructure on at least one of the surface sections of the first and second profile areas of the solidified profile.

[0051] According to a fourth aspect of the invention, generally relating to a device for producing wound hoses, a nozzle for extruding a profile from a thermoplastic material for producing a flexible hose by helically winding the profile around a longitudinal axis, forming a cavity for conveying media, comprises a base body provided with an extrusion gap, which, viewed in the gap cross-section, has a first gap region and a second gap region seamlessly adjoining the first gap region, wherein the first gap region of the extrusion gap is adapted to form a first profile region on the extruded profile for forming recesses of a profiled wall of the hose of a defined wall thickness, while the second gap region of the extrusion gap is adapted toto form a second profile area on the extruded profile to create elevations of the profiled wall of the hose with a defined wall thickness, wherein the first and second gap areas of the extrusion gap are further designed such that they are able to form such first and second profile areas on the extruded profile that interlock during helical winding of the hose, so that the second profile area of ​​a turn of the profile overlaps the first profile area of ​​an adjacent turn of the profile and surface sections remain in a position exposed to the media on the first and second profile areas; according to the invention, the extrusion gap in at least one of the first and second gap areas of the extrusion gap, which serve to generate the surface sections of the first and second profile areas of the extruded profile that remain in a position exposed to the media, has a negative contour that is adapted toA microstructure is formed on the extruded profile in the corresponding surface section, which finely profiles this otherwise smooth surface section, so that in the area of ​​the microstructure the wall thickness varies in a direction normal to the respective surface section of the profile. In this way, the microstructure can be created on the profile in a simple and very reliable manner. Last but not least, the microstructure can also be easily adapted to the respective noise and flow requirements of the hose to be wound. The setup and maintenance effort on the equipment side for the production of hoses with different microstructures on the inside of the wall is advantageously low.

[0052] Further features, properties and advantages of the flexible hose according to the invention, the profile extruded from a thermoplastic material according to the invention for producing a flexible hose, the method according to the invention for producing a flexible hose for conveying media and the nozzle according to the invention for extruding a profile from a thermoplastic material for producing a flexible hose will become apparent to the person skilled in the art from the following description of preferred embodiments.

[0053] BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The invention will now be explained in more detail with reference to preferred embodiments and the accompanying, partly schematic, drawings, in which identical or corresponding parts or sections are provided with the same reference numerals. The drawings show:

[0055] Fig. 1 shows a simply interrupted side view of a flexible hose, namely a vacuum cleaner hose, according to a first embodiment of the invention, which has a cylindrical basic shape and is not yet further assembled, i.e., it has neither hose receiving pieces on both sides nor a sheathing or electrical equipment or the like;

[0056] Fig. 2 shows a longitudinal sectional view of the flexible hose according to Fig. 1 in the area of ​​detail II in Fig. 1 on a significantly enlarged scale, which illustrates in particular that one wall of the flexible hose is formed from a profile extruded from a thermoplastic material and wound helically around a longitudinal axis;

[0057] Fig. 3 shows a further enlarged view of detail III in Fig. 2 in the area of ​​the wall of the flexible hose according to Fig. 1, which in particular shows that the wall on the inside is finely profiled with a microstructure according to the invention, here in the form of circumferential ribs;

[0058] Fig. 4 shows a top view of a basic body of a nozzle for extruding the profile for the production of the flexible hose according to Fig. 1 on the scale of Fig. 3, with a view of the extrusion gap, the cross-sectional geometry of which essentially corresponds to the cross-sectional geometry of the profile;

[0059] Fig. 5 shows a perspective view of the flexible hose according to Fig. 1, broken off to the right, from an oblique angle to the right with respect to the longitudinal axis, on a slightly larger scale than Fig. 2, looking into the cavity bounded by the inside of the wall for conveying media and at a plurality of circumferential surface sections of the wound profile in a position exposed with respect to the media, one of which is provided with the aforementioned circumferential microstructure according to the invention in order to make the wall slightly "unsmooth";

[0060] Fig. 6 shows a perspective view of a quarter segment of the flexible hose according to Fig. 1 from an oblique angle above / left side, scaled to Fig. 5, to further illustrate the microstructure according to the invention in the form of circumferential ribs on the wound profile, which "roughens" the inside of the hose;

[0061] Fig. 7 shows a perspective view of a quarter segment of a variant of the flexible hose of Fig. 1, corresponding to Fig. 6 in terms of viewing angle and scale, in which the microstructure in the form of circumferential ribs is additionally provided with a molded embossing which interrupts the ribs transversely and thus leads to a further roughening of the inside of the hose;

[0062] Fig. 8 shows a two-part interrupted, principal side view of a flexible hose, namely a vacuum cleaner hose, according to a second embodiment of the invention, which has a double-conical basic shape and is again shown in a state before further assembly, where a dashed line transverse to the longitudinal axis indicates where the hose can be divided to obtain two hoses with a conical basic shape;

[0063] Fig. 9 shows a longitudinal section view of the flexible hose according to Fig. 8 in the area of ​​detail IX in Fig. 8, corresponding to the scale of Fig. 3, which shows in particular that the wall of the flexible hose in this embodiment is finely profiled on the inside with a microstructure according to the invention in the form of circumferential grooves;

[0064] Fig. 10 shows a top view of a base body of a nozzle for extruding the profile for the production of the flexible hose according to Fig. 8 on the scale of Fig. 9, with a view of the extrusion gap, the cross-sectional geometry of which essentially corresponds to the cross-sectional geometry of the profile shown in section in Fig. 9;

[0065] Fig. 11 is a perspective view of the flexible hose according to Fig. 8, truncated to the left analogously to Fig. 5, from an oblique angle to the left with respect to the longitudinal axis, on a significantly larger scale than Fig. 8, looking into the cavity bounded by the inside of the wall for conveying media and again at a plurality of circumferential surface sections of the wound profile in a position exposed with respect to the media, one of which is provided with the aforementioned circumferential microstructure according to the invention in the form of circumferential grooves to interrupt the smoothness of the wall; Fig. 12 is similar to the above Fig. 12 in terms of representation and scale.Figures 3 and 9 show a corresponding detail from a longitudinal section view of a flexible hose, namely a vacuum cleaner hose, according to a third embodiment of the invention, which is wound from a different profile to a cylindrical basic shape, the detail particularly illustrating that the wall of the flexible hose in this embodiment is finely profiled on the inside with a microstructure according to the invention in the form of circumferential ribs, which, in comparison to the previous embodiments, are formed on other surface sections of the profile, which are also located in a position exposed to the conveyed media;

[0066] Fig. 13 shows a top view of a base body of a nozzle for extruding the profile for the production of the flexible hose according to Fig. 12 on the scale of Fig. 12, with a view of the extrusion gap, the cross-sectional geometry of which essentially corresponds to the cross-sectional geometry of the profile shown in section in Fig. 12;

[0067] Fig. 14 shows a perspective view of a quarter segment of the flexible hose according to Fig. 12, corresponding to Figs. 6 and 7 above in terms of viewing angle and scale, for further illustration of the inventive microstructure in the form of circumferential ribs on the wound profile, which breaks up the macrogeometric uniformity of the inside of the wall;

[0068] Fig. 15 shows a top view of a production line suitable for manufacturing flexible hoses according to the exemplary embodiments of the invention, the components of which have been grouped into blocks with dashed lines according to the main process steps of extruding a profile, calibrating the profile, cooling the profile, winding the profile into a hose and assembling the wound hose;

[0069] Fig. 16 shows a perspective partial view of the production line according to Fig. 15 with a viewing direction corresponding to arrow XVI in Fig. 15 from an oblique angle above onto a device for calibrating the extruded profile, which in the area indicated by dashed lines may have a toothed or knurled calibration mandrel with a complementarily shaped counter bearing (not shown) in order to produce a corresponding form impression on the still plastically formable profile as a possible further component of the microstructure according to the invention;

[0070] Fig. 17 shows a perspective partial view of the production line according to Fig. 15 with a viewing direction corresponding to arrow XVI I in Fig. 15 from an oblique angle above a device for winding the profile into a tube, which may have teeth or knurling on a winding mandrel shown only schematically, in order to produce a corresponding embossed shape on the solidified profile as a possible further component of the microstructure according to the invention;

[0071] Fig. 18 is a diagram showing the sound pressure level in decibels [dB] versus the frequency in hertz [Hz] for a conventional, microgeometrically smooth inner wall corrugated hose with a cylindrical base in a defined flow state; Fig. 19 is a diagram showing the sound pressure level in decibels [dB] versus the frequency in hertz [Hz] for a corrugated hose with a cylindrical base, microgeometrically uneven on the inner wall according to the invention, again in a defined flow state.

[0072] Fig. 20 is a diagram showing the result of noise level measurements on a defined flow-through, conventional corrugated hose with a cylindrical base shape, which has a microgeometrically smooth inner wall, as a weighted sound pressure level in decibels [dB(A)] over time [Hz]; and

[0073] Fig. 21 shows a diagram in which the result of noise level measurements on a defined flow-through corrugated hose with a cylindrical basic shape, which is microgeometrically uneven or "roughened" on the inside of the wall according to Figs. 1 to 3, 5 and 6 according to the invention, is plotted as a weighted sound pressure level in decibels [dB(A) ] over time [Hz].

[0074] DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0075] In Figures 1 to 3, 5 to 9, 11, 12 and 14, a vacuum cleaner hose, generally designated by reference numeral 10, is shown as an example of a flexible hose. In all illustrated embodiments of the hose 10, a wall 12 of the hose 10 with a defined wall thickness is formed by a profile 16 wound helically around a longitudinal axis 14, as illustrated in particular by Figures 2, 3, 6, 7, 9, 12 and 14. The wall 12, with an inner surface 18, defines a cavity 20 for conveying media, for which the profile 16 has, on the one hand, a plurality of surface sections 22, 24, 26 in a position exposed to the media, and on the other hand, adjacent turns of the profile 16 are connected to each other in a media-tight manner, so that the conveyed medium cannot escape from the hose 10.Here, the coils of the profile 16 form a profiling 30 in macrostructural terms, at least on the inner side 18 of the wall 12 – and in the illustrated embodiments also on its outer side 28. Viewed in section along the longitudinal axis 14 of the hose 10, this profiling 30 has a wave shape with alternating elevations 32 or wave crests and depressions 34 or wave troughs, which is why such a hose 10 is also referred to as a corrugated hose.

[0076] As will be explained in more detail below, a special feature of the hose 10 in the various embodiments is that at least one of the surface sections 22, 24, 26 of the profile 16, which are arranged in a position exposed to the media, is provided with a microstructure 36, so that in the area of ​​the microstructure 36 the wall thickness of the wall 12 varies in a direction normal or perpendicular to the respective surface section 22, 24, 26 of the profile 16. This microstructure 36, which spirals around the longitudinal axis 14 with the wound profile 16, as is best seen in the figures. The feature shown in 2, 5 and 11 serves to fine-profile the corresponding, otherwise smooth surface section 22, 24, 26 of the profile 16, i.e., on a significantly smaller scale than the macrostructural profiling 30, to break up or interrupt the otherwise smooth inner surface 18 of the wall 12 in order to improve the noise behavior of the flow-through hose 10.

[0077] In all the illustrated examples, a profile 16 is used for winding the hose 10, which is extruded from a suitable thermoplastic material, such as polyethylene (PE), polypropylene (PP), or an ethylene-vinyl acetate copolymer (EVAC). As can best be seen in Figures 3, 9, and 12, the profile 16 shown here as an example generally has two areas in a profile cross-section: a first profile area 38 (on the left in each of the figures) and a second profile area 40 (on the right) that is integrally connected to the first profile area 38. The first profile area 38 of the wound profile 16 forms the depressions 34 of the profiling 30 of the wall 12, while the second profile area 40 of the wound profile 16 forms the elevations 32 of the profiling 30 of the wall 12.The second profile area 40 of a turn of the profile 16 is connected to the first profile area 38 of an adjacent turn of the profile 16 in a media-tight manner.

[0078] More precisely, in a cross-section of the profile 16 wound to form the hose 10, the first profile section 38 and the second profile section 40 interlock in such a way that the second profile section 40 of one turn of the profile 16 overlaps the first profile section 38 of an adjacent turn of the profile 16. The surface sections 22, 24, 26 remain on the inside 18 of the wall 12 at the first and second profile sections 38, 40 in a position exposed to the conveyed media. In the area of ​​mutual overlap, the second profile section 40 of one turn of the profile 16 and the first profile section 38 of an adjacent turn of the profile 16 are materially bonded together. This can be achieved, as shown in the figures. 3, 9 and 12, indicated at reference sign 42, a hot melt adhesive is provided which forms a helical seam around the longitudinal axis 14 between the individual turns of the profile 16.The hot melt adhesive 42 can also consist of a thermoplastic material, such as PE or EVAC.

[0079] As can be clearly seen again, particularly in Figures 3, 9 and 12, in the illustrated embodiments, the specific geometry of the profile 16 is chosen such that, viewed in cross-section, the first profile section 38 is essentially U-shaped, with a first web 44 at the beginning of the profile cross-section and a second web 46 opposite the first web 44, which is connected to the first web 44 via an arc-shaped section 48. The second profile section 40, on the other hand, is essentially angled or L-shaped, with a bottom section 50 adjoining the second web 46 of the first profile section 38 and a third web 52 angled away from it at the end of the profile cross-section.

[0080] Viewed in cross-section, the profile 16 wound to form the hose 10, the third web 52 of a turn of the profile 16, acting as a bottom bonding web, overlaps the first web 44 of an adjacent turn of the profile 16, acting as a curved bonding web, and is bonded to it in the area of ​​mutual overlap by means of the hot melt adhesive 42 in a media-tight manner. In the wound state of the profile 16, the webs 44, 46, 52, which run transversely to the longitudinal axis 14, ensure sufficient stability of the hose 10, the curved sections 48, on the other hand, ensure good flexibility of the hose 10, and the bottom sections 50, which extend essentially parallel to the longitudinal axis 14, finally ensure good flow characteristics of the hose 10.

[0081] The aforementioned noise-reducing microstructure 36 can now be formed, according to the respective requirements, on the side facing the cavity 20 on the exposed surface section 22 of the second web 46, as shown, for example, in Fig. 12, and / or on the exposed surface section 24 of the bottom part 50, as shown, for example, in Figs. 3 and 9, and / or on the exposed surface section 26 of the third web 52, as can again be seen particularly well in Fig. 12.

[0082] For the profiles 16 described so far, which serve to manufacture the flexible hose 10 by helically winding the respective profile 16 around the longitudinal axis 14 while forming the cavity 20 for media conveyance, correspondingly adapted nozzles 54 for extruding the respective profile 16 from the thermoplastic material are also shown schematically for the various embodiments of the hose 10 in Figs. 4, 10 and 13.

[0083] These nozzles 54 have in common that they comprise a base body 56 which is provided with an extrusion gap 58. Viewed in cross-section, the extrusion gap 58 has a first gap region 60 and a second gap region 62 that seamlessly adjoins the first gap region 60. The first gap region 60 of the extrusion gap 58 is adapted with regard to its geometry and dimensions to form the first profile region 38 on the extruded profile 16 for the formation of the recesses 34 of the profiled wall 12 of the tube 10. The second gap region 62 of the extrusion gap 58, on the other hand, is adapted with regard to its geometry and dimensions to form the second profile region 40 on the extruded profile 16 for the formation of the protrusions 32 of the profiled wall 12 of the tube 10.The first and second gap areas 60, 62 of the extrusion gap 58 of the respective nozzle 54 are further designed such that they can form first and second profile areas 38, 40 on the extruded profile 16 which interlock when the hose 10 is wound helically, so that the second profile area 40 of a turn of the profile 16 overlaps the first profile area 38 of an adjacent turn of the profile 16 and the aforementioned surface sections 22, 24, 26 remain in an exposed position with respect to the media conveyed through the hose 10 on the first and second profile areas 38, 40.

[0084] A special feature of the nozzles 54 is that in at least one of the first and second gap regions 60, 62 of the extrusion gap 58, which serve to generate the surface sections 22, 24, 26 of the first and second profile regions 38, 40 of the extruded profile 16 that remain in a position exposed to the media, the extrusion gap 58 has one (or more) negative contour(s) 64. This negative contour(s) 64 is (are) adapted with respect to geometry and dimensions to form the aforementioned microstructure 36 on the extruded profile 16 in the corresponding surface section 22, 24, 26, which finely profiles the respective, otherwise smooth surface section 22, 24, 26, so that in the area of ​​the microstructure 36 the wall thickness W of the wall 12 is normal to the surface in one direction. perpendicular to the respective surface section 22, 24, 26 of profile 16 varies.

[0085] The microstructure 36 on the at least one surface section 22, 24, 26 of the profile 16, which is or remains in a position exposed to the media, can now be designed in various ways according to the respective flow, stability, flexibility, and noise requirements for the hose 10. By way of example, Figures 3 and 6 show, in particular, at least one rib 66 for the first embodiment of the hose 10, and in the illustrated example, even three parallel ribs 66 on surface section 24 of the bottom part 50. In this example—see especially Figure 3—the rib 66 has a surface section 24 of the bottom part 50. Each rib 66 of the microstructure 36, seen in cross-section of the profile 16, has a rectangular basic shape, with two opposing side surfaces 68, 70 and a free end surface 72, wherein transitions between the two side surfaces 68, 70 and the free end surface 72 are rounded with a radius. According to Fig.3. The height H of the at least one rib 66 of the microstructure 36, in relation to the average wall thickness W of the profile 16, can be in a range approximately between 1:100 and 1:2. The width B of the at least one rib 66, on the other hand, can be in relation to the average wall thickness W of the profile 16, for example, in a range between 1:20 and 2:1.

[0086] Figures 12 and 14 of the third embodiment show that such ribs 66 can also be formed elsewhere, namely on the surface sections 22 and 26 of the profile 16 that are exposed to the conveyed media. In the first and third embodiments, the three ribs 66 each have the same cross-section and are evenly distributed on the respective surface section 22, 24, 26 of the profile 16, i.e., equally spaced from one another. However, the ribs can also have different cross-sectional areas (with regard to shape and / or size) according to the respective sound refraction requirements and / or be irregularly distributed on the respective surface section, i.e., arranged at different distances from one another on the respective surface section. Likewise, the number of ribs per surface section or the surface section provided with ribs can be varied.It is evident to the person skilled in the art that all this can be achieved by simply modifying the nozzles 54 shown in Figs. 4 and 13 for extruding the respective profile 16 by appropriately adapting the cross-section of the respective extrusion gap 58.

[0087] Alternatively or in addition to the ribs 66 described above, the microstructure 36 can also comprise one or more grooves 74 on at least one surface section 22, 24, 26 of the profile 16 that is arranged or remains in a position exposed to the media. Such a configuration of the microstructure 36 is shown in Figures 9 and 11 for the second embodiment of the hose 10. In this example, analogous to the first embodiment with the ribs 66, three parallel grooves 74 are provided, evenly distributed on the surface section 24 of the profile 16, i.e., equidistant from each other. These grooves 74 can, in turn, be formed in a simple, process-reliable manner by appropriately designing the extrusion gap 58 of the die 54 for extruding the profile 16, as illustrated in Figure 10 for the die 54 in the second embodiment.Corresponding grooves can of course also be formed on surface sections 22 and 26 of profile 16, which is not shown in the figures.

[0088] In the example shown in Figures 9 and 11, each groove 74 of the microstructure 36, viewed in profile cross-section, again has a rectangular base shape, with two flanks 76, 78 facing away from each other, as can be seen on the left in Figure 9, and a base surface 80, with transitions between the two flanks 76, 78 and the base surface 80 being rounded with a radius. According to Figure 9, the depth T of the at least one groove 74 of the microstructure 36, in relation to the average wall thickness W of the profile 16, can be in a range between 1:100 and 1:2. The width B of the at least one groove 74, on the other hand, can be in a range between 1:20 and 2:1 in relation to the average wall thickness W of the profile 16. What has been said above regarding the cross-sectional geometry (shape and / or size), position, distribution and / or number of the ribs 66 applies accordingly to the grooves 74, i.e.These parameters can also be easily varied and adapted to the respective sound refraction requirements by appropriately designing the extrusion gap 58 in the nozzle 54.

[0089] The relative specifications for ribs 66 and grooves 74 refer to standard hose dimensions, i.e. hoses with a diameter range between 15 and 150 mm, which generally have wall thicknesses between 0.5 and 2.0 mm.

[0090] Alternatively or in addition to the ribs 66 and grooves 74 described above, which can be formed during the extrusion of the profile 16 on the surface sections 22, 24, 26 of the profile 16 that are later located in a position exposed to the conveyed media, the microstructure 36 can also be formed or modified differently, for example by embossing the corresponding surface sections 22, 24, 26 on the profile 16, which can be applied after the extrusion of the profile 16 and before or during the winding of the profile 16 to form the hose 10, so that in the area of ​​the microstructure 36 the wall thickness of the wall 12 varies in a defined direction normal or perpendicular to the respective surface section 22, 24, 26 of the profile 16, even if only slightly.

[0091] As an example of such a configuration of the microstructure 36, Fig. 7 shows a variant of the first embodiment of the hose 10, in which a tooth or knurled embossing 82 is superimposed on the ribs 66 produced as described above on the profile 16, which breaks up the ribs 66 in a direction transverse to the rib direction. Such a embossing can, of course, also be applied, in particular, to the surface section 24 of the profile 16 in order to form the microstructure 36 alone, i.e., without the profile 16 otherwise having to have ribs or grooves formed during extrusion.

[0092] Regarding possible cross-sections of the profile 16, a further special feature of the third embodiment of the hose 10 shown in Figures 12 and 14 is that the second profile section 40 is provided with a thickening 84 at its end, i.e., at the third web 52, as can be clearly seen on the left side of Figure 12. Viewed in cross-section of the profile 16 wound to form the hose 10, the thickening 84 of the second profile section 40 of a turn of the profile 16 reduces the volume of the recess 34 of the profiling 30 of the wall 12 formed by the first profile section 38 of an adjacent turn of the profile 16. Tests by the inventors have shown that this measure—which can also be provided in principle in the other embodiments of the hose 10—can contribute to low background noise of the hose 10, even at high flow rates.

[0093] Finally, regarding the basic shape of the hose 10, it should be noted that the profile 16 can be wound along a helix around the longitudinal axis 14 towards the wall 12 of the hose 10 with a cylindrical basic shape, as shown in Fig. 1 for the first embodiment, a conical basic shape, or a doubly conical basic shape, as shown in Fig. 8 for the second embodiment. The macrogeometry (profiling 30 in a wave shape with protrusions 32 and depressions 34) and microgeometry (microstructure 36 on certain surface sections 22, 24, 26) of the proposed hose 10 or profile 16 in the various embodiments readily accommodates these different winding variants.

[0094] A method for producing the flexible hose 10 described so far generally comprises the following five main process steps a) to e): a) Extruding the profile 16 from a thermoplastic material, comprising, in profile cross-section, the first and second profile areas 38, 40, which are formed to create the inner depressions 34 and inner protrusions 32 of the profiled wall 12 of the hose 10 of defined wall thickness; b) Calibrating the extruded, still plastically deformable profile 16 to fine-shape a geometrically defined profile cross-section; c) Cooling the calibrated profile 16 to fix the geometrically defined profile cross-section;d) Winding the cooled profile 16 to form the hose 10, wherein the first and second profile sections 38, 40 are helically interlocked and, leaving the surface sections 22, 24, 26 in a position exposed to the media, are joined together in a media-tight manner; and final e) assembly of the wound hose 10. A special feature of this process is that in one or more of the above main process steps a) to d), at least on one of the surface sections 22, 24, 26 of the first and second profile sections 38, 40, the microstructure 36 is formed in a process-reliable manner, which finely profiles this otherwise smooth surface section 22, 24, 26, so that in the area of ​​the microstructure 36 the wall thickness W of the wall 12 is normal or perpendicular to the surface in one direction. perpendicular to the respective surface section 22, 24, 26 of profile 16, the variations will be described in more detail below.

[0095] In this context, Fig. 15 shows a device for manufacturing a wound hose 10 from a thermoplastic material, generally designated by reference numeral 90. According to the main process steps a) to e) above, the device 90 can generally be divided into five manufacturing blocks, each shown with dashed lines in Fig. 15.Specifically, this comprises an extruder 92 for extruding the profile 16, a calibration device 94 by means of which the extruded, still plastically malleable profile 16 is finely shaped to obtain a geometrically clearly defined profile cross-section, a cooling device 96 in which the calibrated profile 16 is cooled to fix the geometrically clearly defined profile cross-section, a winding device 98 in which the cooled profile 16 is wound overlappingly to form the hose 10, whereby overlapping surface sections of the profile 16 are joined together in a media-tight manner, and a finishing device 100 in which the finished wound hoses 10 are finished according to the specifications, e.g. cut to length.

[0096] The extruder 92 has a die head 102 with a nozzle 54, which comprises a base body 56 provided with an extrusion gap 58. Possible shapes for the nozzle 54, base body 56, and extrusion gap 58 of the extruder 92 are shown for the various embodiments of the tubes 10 in Figures 4, 10, and 13. The extrudate is discharged through the extrusion gap 58 of the respective nozzle 54 in a plastically malleable state, the cross-sectional shape of the extrudate already roughly corresponding to the cross-sectional shape of the profile 16.

[0097] In the production direction behind the die head 102, the calibration unit 94 is arranged, in which the still plastically malleable extrudate is finely shaped so that it acquires a geometrically well-defined, i.e., calibrated, profile cross-section, as can be seen, for example, in Figures 3, 9, and 12. The calibration unit 94, shown enlarged in Figure 16, is, in the illustrated embodiment, arranged in a front section of a cooling section 104 of the cooling unit 96 filled with temperature-controlled cooling water, such that the extrudate is already surrounded by the cooling water and thus pre-cooled to some extent before entering the calibration unit 94. Following the calibration process, which takes place in / under the cooling water, the calibrated profile 16 solidifies completely while being drawn through the cooling section 104 of the cooling unit 96.

[0098] In the area of ​​the cooling device 96, the calibrated profile 16 is then dried before being drawn off via a deflecting roller 106 into the winding device 98, shown enlarged in Fig. 17. The advance of the solidified profile 16 is generated by a draw-off motor 108, which drives a draw-off roller 110. The profile 16 coming from the deflecting roller 106 rests on the draw-off roller 110, where it is pressed against the draw-off roller 110 by means of a pressure roller 112.

[0099] From here, the profile 16 is guided over a profile roller 114 and deflected downwards so that it comes into contact with a winding mandrel 116, which is also driven by rotation. With the aid of the winding mandrel 116, the profile 16, which then rotates around or wraps around the mandrel 116, is wound to form the hose 10. For better visibility of the winding mandrel 116, a guide device located near the winding mandrel 116 has been omitted in Fig. 17. This guide device includes a bending element for the profile 16, by means of which the pitch or angle of the profile 16 relative to the winding mandrel 116, and thus the feed rate and the hose diameter during winding of the hose 10, can be adjusted.

[0100] As mentioned above and clearly visible, for example, in the sectional views according to Figures 3, 9, and 12, the first profile section 38 and the second profile section 40 are adapted to interlock during the helical winding of the hose 10, such that the second profile section 40 of one turn of the profile 16 overlaps the first profile section 38 of an adjacent turn of the profile 16. In the area of ​​this profile overlap, the hot melt adhesive 42 is used to create a media-tight connection between the adjacent turns of the profile 16, forming the helically circumferential seam shown in Figures 3, 9, and 12.

[0101] For melting this hot melt adhesive 42, a further extruder 118, associated with the winding device 98, is provided, as shown in Fig. 15. The hot melt adhesive 42 melted in this extruder 118 is applied to one of the first and third webs 44, 52 of the profile 16 by means of a nozzle 120 positioned between the profile roll 114 and the winding mandrel 116 as shown in Fig. 17, such that it wets and bonds the corresponding adhesive surfaces on the webs 44, 52 during the subsequent winding of the profile 16.

[0102] The hose 10, which forms continuously on the winding mandrel 116 in a continuous production process, then "grows" – according to the set feed rate per revolution of the winding mandrel 116 – towards the assembly device 100, where, in the embodiment shown here, it is merely cooled and cut to length. For the sake of completeness, further possible assembly steps should be mentioned here, such as providing a hose sheath, e.g., in the form of a braid, fitting the hose 10 with end pieces or connectors, equipping the hose 10 with supply cables or means for dissipating static charges, etc. It is often the case that the hose manufacturer further assembles the hose 10 accordingly.

[0103] Of course, the aforementioned hose 10 can also be produced as rolled goods by the hose manufacturer and delivered to, for example, manufacturers of relevant end devices, such as vacuum cleaners, where further processing of the hose 10 then takes place. This processing includes at least cutting the hose 10 to length and usually also fitting the hose 10 with application-specific end pieces. It is readily apparent to those skilled in the art that in the device 90 described above, during the main process step a) of extruding the profile 16, at least one rib 66 and / or at least one groove 74 can be formed as part of the microstructure 36 on at least one of the surface sections 22, 24, 26 of the first and second profile areas 38, 40, namely by using a correspondingly designed nozzle 54 (see Figures 4, 10 and 13).

[0104] As an alternative or supplement to this, in the main process step b), during the calibration of the extruded, still plastically formable profile 16, a form embossing, preferably a tooth or knurled embossing 82 (see Fig. 7) can be formed as part of the microstructure 36 on at least one of the surface sections 22, 24, 26 of the first and second profile areas 38, 40. For this purpose, for example, a calibration mandrel 122 (shown only schematically in Fig. 16) arranged to rotate in the calibration device 94 can be provided with a corresponding negative contour over which the profile 16 is guided for impression forming.

[0105] More precisely, an embossing device 124 can be arranged in the box indicated by dashed lines in Fig. 16, in which a second calibration mandrel or a pressure roller or the like (not shown) is provided in the manner of a matrix-matrices pairing, which works together with the calibration mandrel 122 to produce a corresponding embossing as part of the microstructure 36 on the still unsolidified plastic material of the profile 16.

[0106] As an alternative or supplement to this, a embossed feature, for example a tooth or knurled feature 82 (see again Fig. 7), can be formed as part of the microstructure 36 in at least one of the main process steps c) cooling the calibrated profile 16 and d) winding the cooled profile 16 on at least one of the surface sections 22, 24, 26 of the first and second profile areas 38, 40 of the solidified profile 16. Suitable locations for this would be, for example, in the winding device 98, the engagement point between the take-off roller 110 and the pressure roller 112 and / or the winding mandrel 116, for which these parts would only need to be provided with a corresponding circumferential profile. Such a embossing unit can also be provided in the cooling section 104 to form, for example, a tooth or knurled feature 82 as part of the microstructure 36. a tooth or knurled embossing 82 in the solidified profile material to form this plastically.

[0107] The diagrams shown by way of example in Figs. 18 to 21 ultimately result from comparative investigations carried out by the inventors with conventionally and according to the invention designed hoses 10.

[0108] To determine the noise emissions from the hoses, the hoses were connected to a vacuum cleaner specifically designed for them and laid out in a defined spatial loop. During these tests, the vacuum cleaner was operated at its maximum suction power, with the airflow direction at the unthrottled / open air inlet of the hoses controlled by a flap. With the conventionally designed hoses, it was possible to generate audible whistling noises under certain flap positions.

[0109] The diagram in Fig. 20 shows the (weighted) sound pressure levels in dB(A) recorded over time during two tests on conventional hoses. The whistling noises that overpower the background noise of the hose at certain valve positions can be easily identified by the upward-sloping sound pressure peaks, which, for example, in the first measurement (Measurement 1), cause the (weighted) sound pressure level to increase from approximately 65 dB(A) at time t = 12 seconds to over 90 dB(A) at time t = 14 seconds.

[0110] Figure 18 shows a snapshot of the sound pressure level (dB) versus the frequency of the sound during such a whistling phase at approximately time t = 13 seconds (this time is marked with a dashed line in Figure 20). The whistling noises responsible for the increase in the overall sound level are therefore in a frequency range between 8,000 Hz and 9,000 Hz and between 16,300 Hz and 17,500 Hz, with the lower frequency range being perceived as particularly unpleasant by the human ear.

[0111] For comparison with conventionally designed hoses (i.e., without microstructure), Fig. 21 illustrates the results of two further noise emission measurements, which were recorded over time as part of a test series with vacuum cleaner hoses designed according to the invention with the microstructure 36 according to Fig. 3 under the same test conditions as described above. With the microstructured, ribbed vacuum cleaner hoses tested here, which were cylindrically shaped according to the first embodiment, no undesirable whistling noises could be provoked by influencing the angle of attack. The (weighted) sound pressure levels dB(A) are consistently within the range of the background noise of conventional vacuum cleaner hoses, between 65 dB(A) and 70 dB(A).

[0112] Furthermore, the sound pressure level dB plotted against the frequency in Fig. 19 of the measurement 1 on the hose 10 according to the invention at time t = 20 seconds (again indicated by a dashed line in Fig. 21) no longer shows any maxima that would correspond to the exaggerated frequency ranges between 8,000 Hz and 9,000 Hz or between 16,300 Hz and 17,500 Hz shown in Fig. 18 for the conventionally designed hose.

[0113] A flexible hose has a wall formed from a profile wound helically around a longitudinal axis, with an inner surface that defines a cavity for conveying the medium. For this purpose, the profile has several surface sections exposed to the medium, while adjacent turns of the profile are sealed together to prevent media penetration. The turns form a profile, at least on the inner surface of the wall, which, viewed in cross-section along the longitudinal axis, has a wave-like shape with ridges and depressions. At least one of the aforementioned surface sections is provided with a microstructure that spirals around the longitudinal axis along the wound profile, finely profiling this otherwise smooth surface section. This results in a wall thickness that varies in the microstructured area in a direction perpendicular to the respective surface section of the profile.Furthermore, such a hose profile, a method for manufacturing such a hose, and a nozzle that can be used for extruding such a hose profile are proposed.

[0114] REFERENCE MARK LIST

[0115] Hose Wall Longitudinal axis Profile Inside Cavity Surface section Surface section Surface section Outside Profiling Raising Depression Microstructure First profile area Second profile area Hot melt adhesive First rib Second rib Curved section Bottom section Third rib Nozzle Base body Extrusion gap First gap area Second gap area Negative contour Rib

[0116] Side surface Side surface End surface Groove Flank Flank 0 Bottom surface 2 Tooth or knurling embossing 4 Thickening 0 Device 2 Extruder 4 Calibration device 6 Cooling device 8 Winding device 0 Finishing device 2 Injection head 4 Cooling section 6 Deflection roller 8 Take-off motor 0 Take-off roller 2 Pressure roller 4 Profile roller 6 Winding mandrel 8 Extruder 0 Nozzle 2 Calibration mandrel

[0117] B Width of the rib or groove

[0118] H Height of the rib

[0119] T Depth of the groove

[0120] W average wall thickness of the profile

Claims

PATENT CLAIMS:

1. Flexible hose (10), in particular a vacuum cleaner hose, with a wall (12) of defined wall thickness (W) formed from a profile (16) wound helically around a longitudinal axis (14), which, with an inner side (18), defines a cavity (20) for conveying media, wherein the profile (16) has a plurality of surface sections (22, 24, 26) in a position exposed to the media and adjacent turns of the profile (16) are connected to each other in a media-tight manner, wherein the turns form a profile (30) at least on the inner side (18) of the wall (12) which, viewed in section along the longitudinal axis (14) of the hose (10), has a wave shape with protrusions (32) and depressions (34), characterized in that at least one of the surface sections (22, 24, 26) of the profile (16) arranged in a position exposed to the media is provided with a microstructure (36). is,which spirals around the longitudinal axis (14) with the wound profile (16) and finely profiles this otherwise smooth surface section (22, 24, 26), so that in the area of ​​the microstructure (36) the wall thickness (W) of the wall (12) varies in a direction normal to the respective surface section (22, 24, 26) of the profile (16).

2. Flexible hose (10) according to claim 1, characterized in that the profile (16) in a profile cross-section has a first profile region (38) and a second profile region (40) integrally adjoining the first profile region (38), wherein the first profile region (38) of the wound profile (16) forms the recesses (34) of the profiling (30) of the wall (12), while the second profile region (40) of the wound profile (16) forms the projections (32) of the profiling (30) of the wall (12), and wherein the second profile region (40) of a turn of the profile (16) with the The first profile area (38) of an adjacent turn of the profile (16) is connected in a media-tight manner.

3. Flexible hose (10) according to claim 2, characterized in that, viewed in a cross-section of the profile (16) wound to form the hose (10), the first profile area (38) and the second profile area (40) interlock in such a way that the second profile area (40) of a turn of the profile (16) overlaps the first profile area (38) of an adjacent turn of the profile (16) and otherwise the surface sections (22, 24, 26) on the inside (18) of the wall (12) of the first and second profile areas (38, 40) remain in a position exposed to the media.

4. Flexible hose (10) according to claim 3, characterized in that the second profile area (40) of a turn of the profile (16) and the first profile area (38) of an adjacent turn of the profile (16) are materially connected to each other in the area of ​​mutual overlap.

5. Flexible hose (10) according to claim 3 or 4, characterized in that the second profile area (40) is provided at its end with a thickening (84), wherein, in cross-section of the profile (16) wound to form the hose (10), the thickening (84) of the second profile area (40) of a turn of the profile (16) reduces in volume the depression (34) of the profiling (30) of the wall (12) formed by the first profile area (38) of an adjacent turn of the profile (16).

6. Flexible hose (10) according to one of claims 2 to 5, characterized in that, viewed in profile cross-section, the first profile region (38) is essentially U-shaped, with a first web (44) at the beginning of the profile cross-section and a second web (46) opposite the first web (44), which connects to the first web (44) via an arc- part (48) is connected, while the second profile area (40) is essentially angled or L-shaped, with a bottom part (50) adjoining the second web (46) of the first profile area (38) and a third web (52) angled away from it at the end of the profile cross-section, wherein the microstructure (36) is formed on the side facing the cavity (20) on a surface section (22) of the second web (46) and / or a surface section (24) of the bottom part (50) and / or a surface section (26) of the third web (52).

7. Flexible hose (10) according to at least claims 4 and 6, characterized in that, viewed in cross-section of the profile (16) wound to form the hose (10), the third web (52) of a turn of the profile (16) overlaps the first web (44) of an adjacent turn of the profile (16) and is bonded to it in a media-tight manner in the area of ​​mutual overlap.

8. Flexible hose (10) according to one of the preceding claims, characterized in that the profile (16) is wound along a helix around the longitudinal axis (14) to the wall (12) of the hose (10) having a cylindrical, conical or doubly conical basic shape.

9. Profile (16) which is extruded from a thermoplastic material and can be wound helically around a longitudinal axis (14) for the production of a flexible hose (10), in particular according to one of the preceding claims, for the delimitation of a cavity (20) for conveying media, comprising a first profile area (38) which is provided for forming recesses (34) of a profiled wall (12) of the hose (10) of defined wall thickness (W), and a second profile area (40) integrally adjoining the first profile area (38) which is provided for forming recesses (34) of a profiled wall (12) of defined wall thickness (W), and a second profile area (40) which is provided for forming recesses (34) of a profiled wall (12) of defined wall thickness (W). The purpose is to form elevations (32) of the profiled wall (12) of the hose (10) of defined wall thickness (W), wherein the first profile area (38) and the second profile area (40) are adapted to interlock during helical winding of the hose (10) such that the second profile area (40) of one turn of the profile (16) overlaps the first profile area (38) of an adjacent turn of the profile (16) and surface sections (22, 24, 26) remain in a position exposed to the media on the first and second profile areas (38, 40), characterized in that at least one of the surface sections (22, 24, 26) of the first and second profile areas (38, 40) remaining in a position exposed to the media is provided with a microstructure (36) which finely profiles this otherwise smooth surface section (22, 24, 26).so that in the area of ​​the microstructure (36) the wall thickness (W) of the wall (12) varies in a direction normal to the respective surface section (22, 24, 26) of the profile (16).

10. Flexible hose (10) according to one of claims 1 to 8 or profile (16) according to claim 9, characterized in that the microstructure (36) on the at least one surface section (22, 24, 26) of the profile (16) arranged or remaining in a position exposed to the media comprises at least one rib (66) and / or at least one groove (74) and / or a tooth and / or knurled embossing (82).

11. Flexible hose (10) or profile (16) according to claim 10, characterized in that the at least one rib (66) of the microstructure (36) has a rectangular basic shape in the profile cross-section, with two opposite side surfaces (68, 70) and a free end surface (72), wherein transitions between the two side surfaces (68, 70) and the free end surface (72) are rounded, and / or the at least one groove (74) of the microstructure (36) in the profile cross-section has a rectangular basic shape, with two flanks (76, 78) facing away from each other and a bottom surface (80), wherein transitions between the two flanks (76, 78) and the bottom surface (80) are rounded.

12. Flexible hose (10) or profile (16) according to claim 10 or 11, characterized in that the height (H) of the at least one rib (66) of the microstructure (36) in relation to an average wall thickness (W) of the profile (16) is in a range between 1:100 and 1:2 and / or the width (B) of the at least one rib (66) of the microstructure (36) in relation to the average wall thickness (W) of the profile (16) is in a range between 1:20 and 2:1 and / or the depth (T) of the at least one groove (74) of the microstructure (36) in relation to the average wall thickness (W) of the profile (16) is in a range between 1:100 and 1:2 and / or the width (B) of the at least one groove (74) of the microstructure (36) in relation to the average wall thickness (W) of the profile (16) is in a range between 1:100 and 1:2 Profiles (16) lies in a range between 1:20 and 2:

1.

13. Method for producing a flexible hose (10) for conveying media, in particular according to one of claims 1 to 8 and 10 to 12, comprising the following main process steps carried out in the specified order: a) Extruding a profile (16) from a thermoplastic polymer, comprising, in profile cross-section, first and second profile areas (38, 40) which are formed to create internal depressions (34) and internal protrusions (32) of a profiled wall (12) of the hose (10) of defined wall thickness (W); b) Calibrating the extruded, still plastically malleable profile (16) to fine-shape a geometrically defined profile cross-section; c) Cooling the calibrated profile (16) to fix the geometrically defined profile cross-section; d) Winding the cooled profile (16) to form the hose (10), wherein the first and second profile sections (38, 40) are helically engaged with each other and, leaving surface sections (22, 24, 26) in a position exposed to the media, are joined together in a media-tight manner; e) Assembling the wound hose (10);characterized in that in one or more of the main process steps a) to d) a microstructure (36) is formed at least on one of the surface sections (22, 24, 26) of the first and second profile areas (38, 40), which finely profiles this otherwise smooth surface section (22, 24, 26), so that in the area of ​​the microstructure (36) the wall thickness (W) of the wall (12) varies in a direction normal to the respective surface section (22, 24, 26) of the profile (16).

14. The method according to claim 13, characterized in that in the main process step a) during extrusion of the profile (16) at least one rib (66) and / or at least one groove (74) is formed as part of the microstructure (36) on at least one of the surface sections (22, 24, 26) of the first and second profile regions (38, 40); and / or in the main process step b) during calibration of the extruded, still plastically formable profile (16) at least one of the surface sections (22, 24, 26) of the first and second profile regions (38, 40) a molded embossing, preferably a tooth or knurled embossing (82) is formed as part of the microstructure (36); and / or in at least one of the main process steps c) of cooling the calibrated profile (16) and d) of winding the a shaped embossing, preferably a tooth or knurled embossing (82) as part of the microstructure (36) is formed on at least one of the surface sections (22, 24, 26) of the first and second profile areas (38, 40) of the cooled profile (16) on at least one of the surface sections (22, 24, 26) of the first and second profile areas (38, 40) of the solidified profile (16).

15. Nozzle (54) for extruding a profile (16) from a thermoplastic material for producing a flexible hose (10) by helically winding the profile (16) around a longitudinal axis (14) forming a cavity (20) for conveying media, comprising a base body (56) provided with an extrusion gap (58) which, viewed in the gap cross-section, has a first gap region (60) and a second gap region (62) seamlessly adjoining the first gap region (60), wherein the first gap region (60) of the extrusion gap (58) is adapted to form a first profile region (38) on the extruded profile (16) for forming recesses (34) of a profiled wall (12) of the hose (10) of a defined wall thickness (W), while the second gap region (62) of the extrusion gap (58) is adapteda second profile area (40) is formed on the extruded profile (16) to create elevations (32) of the profiled wall (12) of the tube (10) of defined wall thickness (W), wherein the first and second gap areas (60, 62) of the extrusion gap (58) are further designed such that they are able to form first and second profile areas (38, 40) on the extruded profile (16) which interlock when the tube (10) is wound helically, so that the second profile area (40) of a turn of the profile (16) overlaps the first profile area (38) of an adjacent turn of the profile (16) and surface sections (22, 24, 26) remain in a position exposed to the media on the first and second profile areas (38, 40), characterized in that in at least one of the first and second gap regions (60, 62) of the extrusion gap (58) which serve to generate the surface sections (22, 24, 26) of the first and second profile regions (38, 40) of the extruded profile (16) remaining in a position exposed to the media, the extrusion gap (58) has a negative contour (64) which is adapted to form a microstructure (36) on the extruded profile (16) in the corresponding surface section (22, 24, 26) which finely profiles this otherwise smooth surface section (22, 24, 26), so that in the area of ​​the microstructure (36) the wall thickness (W) of the wall (12) varies in a direction normal to the respective surface section (22, 24, 26) of the profile (16).

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