Heating device for a fluid line

Abstract

Heating device (10) for a fluid line (12), preferably for a gas fluid line, comprising a thermally conductive pipe segment (14) through which the fluid flows, an electric heating element (16) for heating the pipe segment (14), and an electrical connector (18), wherein the heating element (16) is electrically connected to the connector (18) via contact elements (20), wherein the heating element (16) and the contact elements (20) are attached to the pipe segment (14) by a fastening element (22), and the fastening element (22), heating element (16), and pipe segment (14) are encapsulated in a plastic housing (26), wherein the fastening element (22) is designed as a plastic element, wherein the fastening element (22) is attached to the pipe segment (14), wherein the fastening element (22) is snapped, screwed, or glued onto the pipe segment (14), characterized in thatthat the fastening element (22) has a substantially U-shaped cross-sectional profile (110) with respect to the tube segment axis, wherein the side flanks (46) of the fastening element (22) preferably comprise locking elements (36) for locking onto the tube segment (14) and the central flank (48) comprises through-holes (50) for the contact elements (20).

Description

Technical FieldThe invention relates to a heating device for a fluid line, preferably for a gas fluid line, in particular for a ventilation line of a crankcase of an internal combustion engine.Prior ArtHeating devices for fluid lines are widely known in plant construction and are used in particular in internal combustion engines in order to heat liquids or gases in lines to a predeterminable temperature level. Thus, among other things, heating devices for urea-water solutions for diesel injection systems are known, but also heating devices for blow-by gases of a crankcase ventilation system.Blow-by gases occur in internal combustion engines, which are produced by combustion gases in the cylinder passing the cylinder piston into the crankcase. These blow-by gases containing unburned hydrocarbons raise the pressure in the crankcase, which may result in leakage and leakage of oil. In order to avoid a pressure increase and to discharge the blow-by gases in an environmentally friendly manner, they are recirculated from the crankcase into the air intake tract of the internal combustion engine. Due to the high pressure differences between the crankcase and the air intake area, the gases usually cool and there is the risk of condensation, wherein dirt particles deposit in the air intake tract and lead to contamination. For this reason, heating devices are used in the venting valves or in the crankcase venting lines, wherein the recirculated gases are heated to a desired temperature by means of a PTC element (positive temperature coefficient element-PTC thermistor). PTC elements generally consist of a semiconducting polycrystalline ceramic, for example barium titanate, which are formulated in a disk-shaped or plate-shaped manner and can be energized by means of metallic contact elements. Such heating devices generally have a pipe or line segment made of a thermally conductive material, for example copper, aluminum or steel, in which the fluid to be heated can flow, wherein the pipe segment is coupled to an electrical heating element for heating the pipe segment. The electrical heating element is generally connected to the power supply of the internal combustion engine via an electrical plug-in connection device.Heating devices are known from the prior art, which are partially sealed against aggressive blow-by gases, wherein a heating element is soldered onto a pipe segment or glued on by means of a thermally conductive adhesive. Furthermore, it is known to spray an electrical plug-in connection device onto the pipe segment, wherein the heating element and its electrical contacting are pressed onto the pipe segment by means of spring force. Finally, shrunk-on heating elements or pressed-in or caulked heating elements on a pipe segment are known, which are encapsulated by injection molding with a plastic housing.A heating device is known from DE 10 2007 026 805 A1, wherein a heating element is encapsulated by a plastic housing on a pipe segment by injection molding and multilayer laminate sealing rings are arranged at the two axial ends of the pipe segment for sealing. The heating element is welded directly to the pipe segment through the plastic housing.DE 60 2004 011 246 T2 discloses a heating device for crankcase ventilation pipes in internal combustion engines, in which the mechanical contact between the electrical contact elements, the PTC element and the pipe is more reliable and stable both during and after the molding process. A heating device is described in which the PTC element is firmly sandwiched between the contact elements.DE 198 46 282 A1 discloses a fastening for the heating elements for a heatable wall, in particular a heating tube, which fastening makes do without a soldered connection or adhesive connection. The heating elements are placed directly on the inner tube and pressed by springs. The prestress of the springs is produced by placing the cover in the installation opening provided for this purpose. These components can be connected to an electrical circuit via contact tongues.DE 10 2010 033 757 A1 discloses a fluid conducting device, in particular a blow-by device with an electrically conductive unit, which is attached to a coupling piece and is electrically contacted via a plug. This plug can only be fitted when the electrically conductive unit is properly fitted to the coupling piece.EP 1 375 998 A1 discloses a heating device for fluid feedthroughs, preferably for blow-by pipes in connection with crankcase ventilation, and a method for mounting such a heating device, as well as an internal combustion engine having such a heating device. The holding device has a clamping spring with a semicircular cross section, which at least partially engages around the tube and can be mounted in a direction which runs substantially transversely to the direction of the fluid flow.EP 1 375 999 A1 discloses a heating device for a fluid line, in particular for crankcase ventilation of an internal combustion engine. The heating device comprises a heating element, preferably a PTC heating element, and a holding device, by means of which the heating element can be fastened to the fluid line. Heating element and holding device can be inserted into a shaft of the fluid line opening in the radial direction.EP 1 772 613 A1 describes a heating device in which a heating element is pressed onto a tube segment by a contact spring, wherein the contact spring is welded into a plastic housing and is formed with a plug connection device.US 2007 / 0 186 913 A1 is concerned with preventing freezing of a water content in a venting pipe. For this purpose, a heater is arranged in a vent pipe which connects a cylinder head cover and an air filter.US 2006 / 0 144 376 A1 discloses a heating device for a fluid line, in particular for a crankcase ventilation in an internal combustion engine, having a heating element and having a holding device, by means of which the heating element can be mounted on the fluid line.DE 103 35 716 A1 relates to a connection between a metallic component and a sheath layer of thermoplastic or thermosetting plastic or polymer ceramic substantially surrounding the component, and to a device having a component and a sheath layer substantially surrounding the component.DE 103 25 965 A1 discloses a heating device for fluids, in particular gases, comprising a tube carrying the fluid, a non-conductive jacket, and a heating element arranged on the fluid-carrying tube, wherein the heating element is embedded contactingly in a first opening of the jacket of the fluid-carrying tube and wherein a further contact point of the fluid-carrying tube is arranged in a further opening of the jacket.In addition, DE 103 26 894 B3 discloses a heating device which can be fastened around a line in a clamp-like manner. The heating element is encapsulated on an axial extension of the transfer clamp in a plastic housing, wherein the heating element is pressed onto the thermally conductive extension of the pipe clamp.Proceeding from the aforementioned prior art, it is an object of the invention to propose a heating device which enables simple production, offers improved insulation against blow-by gases and provides a high electrical and thermal contacting quality.The aforementioned object is achieved by a heating device for a fluid line, in which a fastening element clamps a heating element onto a pipe segment to be heated, wherein pipe segment, heating element and pipe segment are encapsulated in a plastic housing. Furthermore, the object is achieved by a fluid line which comprises such a heating device.Disclosure of the InventionThe invention is based on a heating device for a fluid line, preferably for a gas fluid line, in particular for a venting line of a crankcase of an internal combustion engine, which comprises a thermally conductive pipe segment through which fluid flows, an electric heating element for heating the pipe segment, and an electric plug connection device. The heating element is electrically connected to the plug connection device via contact elements. The heating element and the contact elements are fastened to the tube segment by a fastening element, and the fastening element, the heating element and the tube segment are encapsulated in a plastic housing.In other words, the invention relates to a heating device in which a heating element, in particular a PTC conductor, which has contact elements for electrical contacting, is screwed, riveted, adhesively bonded or fastened elsewhere to a thermally conductive pipe segment by means of a fastening element, designed as a plastic element. The plastic element presses the heating element onto the region of the pipe segment to be heated. Subsequently, the fastening element with the pressed heating element is encapsulated by injection molding through a plastic housing and thus encapsulated. Because the heating element is not directly injected into a plastic housing, but is initially mechanically fastened to the pipe segment by a fastening element, electrical contacting and defined fastening of the heating element to the thermally conductive pipe segment can be ensured independently of the plastic injection molding. The plastic housing serves merely for protection against external environmental influences and can be encapsulated in a gas-tight manner. Furthermore, the plastic housing shapes the housing of the plug connection device, wherein the contact elements which are directly connected to the heating element can project into the plug connection device. By fastening the heating element on the pipe segment by means of a fastening element, the intermediate product can be pretested electrically, and nondestructive corrections can be carried out before ultimately a plastic housing is injection-molded. The fastening element fixes the heating element on the region of the pipe segment to be heated and guarantees good thermal conductivity and electrical contacting of the heating element by the contact elements, so that a mechanical decoupling from the plastic housing is achieved. In contrast to corrosion-sensitive soldering, conductive bonding of the heating element on the pipe segment, mechanical caulking of the heating element or direct plastic injection molding of the heating element through a plastic housing, the fastening element as a prefabricated component can ensure rapid, robust and contact-proof mounting of the heating element on the pipe segment. The prefabricated component can then be encapsulated by injection molding with a plastic housing of any desired shape according to the requirements for the specific use.The plastic housing accommodates the plug connection device and decouples the heating element mechanically from the plug connection device, so that forces during the electrical contacting, i.e. the sliding of a plug into the plug connection device, have no influence on the fastening and contacting of the heating element on the pipe segment. When the plastic housing is directly encapsulated by injection molding around the heating element, high mechanical pressures and temperatures occur, so that the risk of damage occurs. The heating element can be connected in a form-fitting manner to the pipe segment by the fastening element. Electrical contacting is not impaired during the injection molding. The heating element and the contact elements are protected against mechanical and thermal stress during subsequent processes, in particular during injection molding and here particularly against the injection pressure and the processing temperature. The fastening element and the subsequent plastic injection molding protect a receiving chamber, in which the heating element is located, against the penetration of blow-by gases and no metal migration can occur, so that short circuits due to external contamination are avoided. By using standardized fastening elements, automated assembly of the heating device can be carried out very easily and economically. Furthermore, by consistently implementing the two-stage assembly, functional testing of the intermediate product can be carried out, so that the defect rate can be reduced and the housing shape of the heating device can be easily adapted to design requirements.According to an advantageous development of the invention, a spring element for exerting a contact pressure force from the heating element on the pipe segment can be arranged between the fastening element and the heating element. The spring element exerts a contact force between the fastening element and the heating element in such a way that the heating element can be pressed over a heat contact surface onto a region of the pipe segment to be heated. The strength of the contact pressure of the spring element can be varied. The spring element can be, for example, a compression spring, a conical spring, a spring disk, a disk spring or a spring tongue and can optionally press the electrical contacts of the contact elements together with the heating element or else only the heating element alone onto the region of the pipe segment to be heated. The spring element can establish an electrical contact between contact element and a contact side of the heating element. It is furthermore conceivable that the spring element can be an elastic O-ring or an elastic molded part, for example a rubber ring or elastomer molded part, which can also perform sealing tasks in particular. Through the intermediate arrangement of a spring element between fastening element and heating element, a planar thermal contact is provided for the heat transfer between heating element and tube segment.In an advantageous development, a sealing element for the fluid sealing of the heating element can be arranged between the fastening element and the heating element. By arranging the heating device in a fluid line, in particular when used mechanically in a harsh environment, aggressive gases, for example blow-by gases, can penetrate into the housing of the heating device and can cause corrosion or contamination on the heating element, so that electrical as well as thermal transition resistances form, and thus the efficiency or the function of the heating device can be impaired. By arranging a sealing element between the fastening element and the heating element, a sealing of the heating element can be provided and thus the electrical contact between the contact element and the heating element and the heat transfer between the heating element and the tube segment can be sealed from the environment, so that no contamination and thus no deterioration of the electrical and thermal properties of the heating device can occur over a long service life.In an advantageous development, the sealing element can comprise the spring element, such that the sealing element, which is generally produced from a soft, sealable elastomer, can provide a resilient effect for providing a contact pressure force from heating element on the pipe segment. Thus, the number of components is reduced, the assembly process is simplified and double use of the sealing element is achieved.According to the invention, the fastening element is fastened to the pipe segment. The fastening element can enclose the tube segment in a form-fitting manner or can be pressed onto or caulked onto the tube segment. According to the invention, the fastening element is snapped, screwed or glued onto the tube segment. Particularly advantageously, the fastening element can consist of a prefabricated plastic part which comprises latching elements and can be latched onto latching edges or recesses of the tube segment. Alternatively, it is conceivable that the fastening element is glued onto the pipe segment by means of a suitable, heat-resistant adhesive, or is screwed onto a thread-like extension of the pipe segment. A force-fit and form-fit connection is created by a mechanical application, in particular a snapping-on or screwing-on of the fastening element on the pipe segment, so that the heating element is pressed between the fastening element and the pipe segment and at least partially encapsulated, and has a high connection quality both electrically and thermally.According to an advantageous development, the pipe segment can have an extension to which the fastening element is fastened, wherein the extension is in particular configured in a planar or cylindrical manner and preferably in one piece at an axial end of the pipe segment and preferably has angled longitudinal edge regions, at which the fastening element can be fastened, in particular can be latched on or clamped on. Thus, the extension can project in tongue-like manner from an axial end of the pipe segment, or project at any desired point on the circumferential surface of the pipe segment. In this development, it is proposed that the fastening element is not arranged directly on the pipe segment, but on a flat or cylindrical extension of the pipe segment, wherein the extension can be arranged axially at one end and can be aligned, for example, at an adjustable angle to the pipe segment. Thus, the heating device can be fastened, in particular latched or clamped, to the extension as desired, wherein the actual tube segment is functionally decoupled from the extension and is connected in a thermally conductive manner via the one-piece construction. The extension can protrude at an angle with respect to the tube segment, so that a predefined installation space can be optimally used for integrating the heating device. The extension can be designed in such a way that the fastening element can be snapped on, screwed on, clamped on or glued on, and can in particular have angled longitudinal edges and a flat central region on which the heating element is placed. Thus, in particular, the tube segment can be round and the extension can form a flat surface on which the heating element rests and have angled longitudinal edges on which a bow-shaped fastening element can be latched.According to the invention, the fastening element has a substantially U-shaped cross-sectional profile with respect to the tube segment axis, wherein the side flanks of the fastening element comprise latching elements for latching a tube segment and the central flank comprises plug-through openings for the contact elements. In this development, it is proposed that the fastening element is designed as a bow-shaped or channel-shaped plastic part which has a U-shaped cross section and which carries latching elements on its side edges, with which it can latch or clamp into latching recesses, for example on an extension of the pipe segment or on the pipe segment itself. In the central flank, through-openings can be provided for the passage of contact elements which are in electrical contact with the heating element, wherein the contact elements extend in the direction of the plug connection device in order to contact a plug inserted as terminal lugs. Such a channel-shaped or bow-shaped shaping of the fastening element allows effective latching or adhesive bonding and offers space in the central flank for receiving the heating element, which can preferably be arranged in a depression of the central flank in a shape-matched manner.In an advantageous development, the heating device can comprise a sealing element, wherein the sealing element can be inserted in a complementary shape in a seating boundary of the fastening element, which boundary bounds the region of the pipe segment to be heated by the heating element, wherein the sealing element protrudes from the seating boundary in the direction of the region of the pipe segment surface to be heated. This exemplary embodiment proposes that, in the side of the fastening element which faces the pipe segment and under which the heating element is arranged, a sealing element is placed in a seating boundary of the fastening element in a complementary manner in terms of shape, wherein the sealing element protrudes in the direction of the pipe segment with respect to the seating boundary, such that, when the fastening element is latched or adhesively bonded to the pipe segment, a sealing pressing action is exerted on the elastic sealing element, and therefore the boundary region between the pipe segment surface and the fastening element in which the heating element is arranged is sealed by the sealing element. A fluid-tight space is thus formed, in which the heating element with the electrical contacts is arranged.In an advantageous development, the heating element can be designed in the form of a disk, wherein each contact element comprises a contact part substantially complementary in shape to the disk surface of the heating element for electrically contacting the disk surface and a pin-shaped terminal tab part, wherein the terminal tab part can be inserted through a plug-through opening of the fastening element and / or of the sealing element in the direction of the plug-in connection device and is preferably oriented at right angles to the contact part. In other words, it is proposed here that the heating element is formed as a disk, in particular as a circular disk, and the contact elements are formed on a contact part which is formed in a manner corresponding to the disk surface and is also formed in a disk shape, and on a terminal tab part which is formed as a terminal post or terminal bracket with a round, rectangular or square cross section, wherein the terminal tab part can be guided as a plug part into the plug connection device and can be inserted through insertion openings of the sealing element and / or of the fastening element. As a result of the lead-through of the terminal tab part through lead-through openings of the sealing element, the sealing element hermetically seals the contact elements in the lead-through region, so that contaminants cannot penetrate along the contact elements to the heating element. By virtue of the planar contacting of the contact surfaces with a connection surface of the heating element, an extremely low contact resistance can be formed. Due to the fact that the contact elements have a high conductivity, they conduct heat in particular well, so that a sandwich-like structuring of contact element, heating element and further contact element provides, on the one hand, a good electrical as well as a good thermal coupling of the heating element to the pipe segment. The terminal tab parts are, as it were, components of the plug connection device and can be connected directly by a plug coupling to an electrical network of a system or machine for supplying power to the heating element. Thus, a minimum number of components are required to provide the heater.It is furthermore conceivable that in a comparable construction, instead of the heating element or in addition to the heating element, a temperature-variable resistance element can be used as a temperature sensor, so that a regulation of the heating device is made possible, or the device can be used as a temperature sensor device. For this purpose, instead of or in addition to the heating element, a temperature-variable resistance element can be used between the fastening element and the tube segment.In an independent aspect, the invention relates to a fluid line for an internal combustion engine, preferably a gas fluid line, in particular a venting line for a crankcase, which comprises a heating device according to one of the aforementioned exemplary embodiments. Such a fluid line can be formed in one piece and receive such a heating element at one of the line ends, or can consist of two individual partial lines which are connected to the tube segment of the heating device at the heating element, for example by means of clamps or shrink connections. The fluid line can be a pipeline or a hose line. The fluid line thus comprises a heating device and can heat a fluid to be conveyed to a desired temperature and, for example, protect it from icing or failure of contaminants.Brief Description of the DrawingsFurther advantages are evident from the following description of the drawings. Exemplary embodiments of the invention are illustrated in the drawings. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown by way of example: FIG. 1 shows a fluid line with an exemplary embodiment of a heating device; FIG. 2 is a perspective view of a heating device according to an embodiment of the invention; FIG. 3 is a partial cross-sectional view of the embodiment of FIG. 2; FIG. 4 shows a cross-sectional illustration of the exemplary embodiment according to FIG. 2 ; FIG. 5 shows a tube segment with heating element and fastening element for use in the exemplary embodiment according to FIG. 2 ; FIG. 6 shows a cross-sectional illustration of the pipe segment illustrated in FIG. 5 with heating element and fastening element; FIG. 7 shows an exploded view of an exemplary embodiment of a pipe segment with fastening element and heating element; FIG. 8 is an exploded view of another embodiment; FIG. 9 is an exploded view of another embodiment; FIG. 10 is an exploded view of another embodiment; FIG. 11 is a bottom view of a fastening element with inserted sealing element.Embodiments of the InventionIn the figures, identical or similar components are denoted by identical reference numerals. The figures merely show examples and should not be understood as limiting.FIG. 1 shows a fluid line 12 in which a heating device according to an embodiment 10 of the invention is arranged. A fluid, for example blow-by gases, is guided from a crankcase in the direction of an air intake region of an internal combustion engine and is guided through the heating device 10 by flexible line hoses 12 which are fastened to line connection elements, for example pipe clamps, in a fluid-tight manner to the heating device 10. The fluid is heated by the heating device 10, so that it does not condense, for example, during expansion or does not freeze at low temperatures.FIG. 2 shows a perspective view of a plastic housing 26 of a heating device 10. The plastic housing 26 comprises at its two longitudinal axial ends two line connection regions 24 for connection to fluid lines 12, which can be designed, for example, as a tube or hose lines. In the central heating region 112, a heating element is arranged within a thermally conductive pipe segment, which heats the fluid flowing through. For the electrical contacting, a plug connection device 18 is provided, in which a plug coupling can be inserted and thus the heating element can be supplied with electrical energy.In FIG. 3, a partial longitudinal cross-section through the heating device 10 shown in FIG. 2 is shown. For this purpose, the plastic housing 26 is shown in section, in which a tube segment 60 consisting, for example, of copper or aluminum is arranged with a flat extension 42 formed in one piece. A fluid can be guided through the tube segment 14, wherein a heating element 16, which is pressed onto the extension 42 under a saddle-like fastening element 22 latched onto the extension 42, can transfer heat to the tube segment 14. On the central flank 48 of the fastening element 22, a receiving region 114 is provided, in which the disk-shaped heating element 16 is fitted. The terminal lugs 56 of the two contact elements 20 project into the cup-shaped plug-in connection device 18 in order to be electrically contacted by a plug-in coupling, not shown. On the two side flanks 46 of the fastening element 22, latching elements 36 are provided, which latch on the extension 42 of the pipe segment 14.Starting from FIG. 3, a longitudinal cross section of the heating device 10 according to FIG. 2 is shown in FIG. 4. Here, the disk-shaped heating element 16 is shown cut in the middle and has a planar connection to the extension 42 of the pipe segment 14. Below and above the heating element 16, disc-shaped contact parts 54 of the contact element 20 are arranged, which contact the PTC heating element 16 electrically. A sealing element 34 encloses the heating element 16 and has plug-through openings through which the terminal lugs 56 are inserted, and thus seals the heating element 16 from the environment. The terminal tab 56 is furthermore inserted through an insertion opening of the fastening element 22. For pressing the heating element 16 and the two contact elements 20 onto the flat extension 42 of the pipe segment 14, a spring element 28 is provided, which is arranged between the sealing element 34 and the first contact element 20, and presses the first contact element 20, heating element 16 and second contact element 20 against the thermally conductive surface of the extension 42 of the pipe segment 14.FIG. 5 shows the tube segment 14 with a planar extension 42, the latched-on U-shaped fastening element 22 and the connection lugs 56 of the contact elements 20 which can be contacted by a plug-in coupling. FIG. 6 shows a section through the pipe segment according to FIG. 5 in this respect. Latching noses 38 are arranged as latching elements 36 in the two side flanks 46 of the fastening element 22, which engage at latching edges 40 of the angled left edge region 44 of the flat extension 42 in order to latch the fastening element 22 onto the pipe segment 14. Between the pipe fastening element 22 and the pipe segment 14, a sealing element 34 made of elastomer is arranged, under which a spring element 28 presses the two contact parts 54 of the contact elements 20 and the heating element 16 onto the surface 116 of the pipe segment 14.In detail, four exploded drawings are shown in the following FIGS. 7, 8, 9 and 10, which show the sandwich-like structure of tube segment 14, first contact element 20, heating element 16, second contact element 20, sealing element 34 and fastening element 22 in detail, wherein the design and position of spring element 28 is varied in structure.Thus, FIG. 7 shows a tube segment 60 with a planar extension 42, wherein the surface of the extension 42 defines a heat coupling-in region 116 and has two angled longitudinal edge regions 44, on which latching edges 40 are formed at the respective end edge regions. A disc-shaped contact part 54 of a first contact element 20 is placed on the heat coupling region 116, on which contact part a disc-shaped heating element 16 made of PTC material with a shape-complementary disc surface 108 is seated. A current-conducting cone spring 30 is placed thereon as spring element 28, which is likewise bounded by a second contact element 20 with a disk-shaped contact part 54, and which presses the heating element 16 against the heat coupling region 116. The two terminal tab parts 56 of the contact elements 20 can be inserted through insertion openings 52 of a sealing element 34, wherein the sealing element 34 delimits the heat coupling region 116 and can be inserted in a complementary shape in a seating boundary 100 of the bow-shaped snap-in fastening element 22. The latching element 22 has a U-shaped profile cross section 110 and has a central flank 48, in which a heating element receiving region 114 is provided, which is substantially of shape-complementary disk-shaped design. Furthermore, two plug-through openings 50 are provided for plugging through the terminal lugs 56 of the two contact elements 20. On the inner side flanks 46 of the fastening element 22, latching noses 38 are arranged as latching elements 36, which can latch into the latching edges 40 of the flat extension 42. Due to the sandwich-like construction, the heating element 16 is pressed between the contact parts 54 of the first and second contact element 20 and onto the thermally conductive heat coupling region 116 of the extension 42 of the pipe segment 60. The sealing element 34 seals the heating element 16 and the terminal tab parts 56 from the environment, so that contaminants cannot reach the heating element 16. The multipart construction enables a pre-assembly of the pipe segment 14, which can subsequently be encapsulated by injection molding with a plastic housing 26. The planar extension 42 can be angled with respect to the axial extension of the pipe segment 14, so that a design freedom of the plastic housing 26 is provided.FIG. 8 shows a similar structure to that of FIG. 7 of the pipe segment 60 with heating element 16 and fastening element 22, but the conical spring 30 is arranged in this embodiment between fastening element 22 and second contact element 20 and not between contact element 20 and heating element 16. In FIG. 9, a similar construction is shown as in FIG. 8, but the conical spring 30 as spring element 28 is replaced by an elastomer O-ring spring 32. In FIG. 10, this elastomer O-ring spring part 32 is formed integrally with the sealing element 34, and can be formed integrally as a sealing element 58, for example, using two-component plastic technology. Thus, a sealing member 58 is formed with the spring member 28 integrally arranged, so that the number of components can be reduced, and mispositioning of the spring member 28 during the assembly process can be prevented. As a result, a heating device can be assembled with a small number of components.Finally, FIG. 11 shows the underside of a fastening element 22, in which a sealing element 34 is inserted into the seating boundary 100 of the fastening element 22 in a complementary manner in terms of shape, such that the plug-through openings 52 of the sealing element are aligned with the plug-through openings 50 of the fastening element 22. Such an embodiment can be produced in one piece, in particular as a two-component injection-molded part, so that the number of components can be reduced and the costs can be reduced. The sealing element 34 protrudes with a protrusion 104 above the seating boundary 100 of the fastening element 22, so that when the fastening element 22 is latched on or screwed on, the sealing element 34 reliably seals the region between the heat coupling region 116 and the fastening elements 22. Thus, a fluid-tight heating region 112 in which the heating element 16 is arranged is provided.The proposed heating device is distinguished by a minimum proportion of components and a pre-assembly capability for forming an intermediate product. Contact safety is ensured by a resilient element which is arranged between the fastening element and the heating element and which enables a low electrical and low thermal contact resistance, so that a high efficiency of the heating device can be achieved. Due to the pre-assembly by a mechanical locking, component costs and assembly effort are reduced and a low failure rate is achieved. Functional reliability over the lifetime is ensured and the heating element is protected against mechanical and thermal loads during injection molding processes, during assembly and during operation. The sandwich-like structure of the heating device is suitable for an automated production method. The heating device can be used in particular for heating pipes, heating elements and heated valves for crankcase ventilation.

Claims

Heating device (10) for a fluid line (12), preferably for a gas fluid line, comprising a thermally conductive tube segment (14) through which the fluid can flow, an electrical heating element (16) for heating the tube segment (14) and an electrical plug connection device (18), wherein the heating element (16) is electrically connected to the plug connection device (18) via contact elements (20), wherein the heating element (16) and the contact elements (20) are fastened to the tube segment (14) by a fastening element (22), and the fastening element (22), heating element (16) and tube segment (14) are encapsulated in a plastic housing (26), wherein the fastening element (22) is designed as a plastic element, wherein the fastening element (22) is fastened to the tube segment (14), wherein the fastening element (22) is snapped, screwed or adhesively bonded onto the tube segment (14), characterized in that, the fastening element (22) has a substantially U-shaped cross-sectional profile (110) with respect to the tube segment axis, wherein the side flanks (46) of the fastening element (22) preferably comprise latching elements (36) for latching to the tube segment (14) and the central flank (48) comprises plug-through openings (50) for the contact elements (20).Heating device (10) according to claim 1, characterised in that the fastening element (22) consists of a prefabricated plastic part, wherein the prefabricated plastic part comprises latching elements (36), and can be latched onto latching edges (40) or recesses of the tube segment (14).Heating device (10) according to claim 1, characterised in that the fastening element (22) is glued to the pipe segment (14) by means of a suitable, heat-resistant adhesive.Heating device (10) according to claim 1, characterised in that the fastening element (22) is screwed onto a thread-like extension of the pipe segment (14).Heating device (10) according to one of Claims 1 to 4, characterized in that a spring element (28) for exerting a contact pressure force from heating element (16) on pipe segment (14) is arranged between fastening element (22) and heating element (16).Heating device (10) according to one of Claims 1 to 5, characterized in that a sealing element (34) for the fluid sealing of the heating element (16) is arranged between the fastening element (22) and the heating element (16).Heating device (10) according to claim 6, characterised in that the sealing element (34) comprises the spring element (28).Heating device (10) according to one of the preceding claims, characterized in that the tube segment (14) has an extension to which the fastening element (22) is fastened, wherein the extension is in particular configured in a planar or cylindrical manner and preferably in one piece at an axial end of the tube segment (14), and preferably has angled longitudinal edge regions (44) to which the fastening element (22) can be fastened.Heating device (10) according to one of Claims 6 to 8, characterized in that the sealing element (34) consists of an elastomer, and comprises plug-through openings (52) for the contact elements (20).Heating device (10) according to one of claims 6, 7 or 9, characterised in that the sealing element (34) is inserted in a complementary shape into a seating boundary of the fastening element (22), which boundary bounds the region of the pipe segment (14) to be heated by the heating element (16), wherein the sealing element (34) protrudes from the seating boundary (100) in the direction of the pipe segment surface (102).Heating device (10) according to one of the preceding claims, characterized in that the heating element (16) is disc-shaped, wherein each contact element (20) comprises a contact part (54), which is substantially complementary in shape to the disc surface (108) of the heating element (16), for electrically contacting the disc surface (108), and a pin-shaped terminal tab part (56), wherein the terminal tab part (56) can be inserted through a plug-through opening (50, 52) of the fastening element (22) and / or sealing element (34) in the direction of the plug connection device (18) and is preferably oriented at right angles to the contact part (54).Fluid line (12) for an internal combustion engine, preferably a gas fluid line, in particular a venting line for a crankcase comprising a heating device (10) according to one of the preceding claims.

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