WO2008071348A1

WO2008071348A1 - Electric heater or auxiliary heater, especially for a heating or air-conditioning system of a motor vehicle

Info

Publication number: WO2008071348A1
Application number: PCT/EP2007/010652
Authority: WO
Inventors: Michael Kohl; Otto Jürgen; Erwan Gogmos; Dieter Gross
Original assignee: Behr Gmbh & Co. Kg; Behr France Rouffach Sas
Priority date: 2006-12-11
Filing date: 2007-12-07
Publication date: 2008-06-19
Also published as: EP1933598B1; EP1933598A1

Abstract

The invention relates to an electric heater or auxiliary heater (1), especially for a heating or air-conditioning system of a motor vehicle. Said heater comprises at least one heating element (2) having at least one PTC element which serves to heat a flowing medium, said PTC element having at least one row that consists of a plurality of webs (4) that are interconnected via at least one connecting zone (6), and the PTC element is electrically connected in two opposite edge zones that are perpendicular or substantially perpendicular to the direction of flow of the medium for current lead-in or lead-out. The invention is characterized in that the connecting zone (6) is configured to be interspaced from the electrically contacted edge zones and that the interspaced outer ends of outer webs (4a) that are positioned on the outside thereof serve for current lead-in or lead-out.

Description

Electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle

The invention relates to an electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, according to the preamble of claim 1.

In low-consumption vehicles is due to the low waste heat an additional heating power to heat the

Passenger compartment and for the quick elimination of a fitting (ice or

Water) in particular on the windshield required. For this purpose, it is known in heat exchangers, which are constructed of flat tubes through which a heat transfer medium flows, which emits heat in the heating case, at least at the outermost tubes an additional heating in

BESTATIGUNGSKOPIE Provide PTC heating elements form, which are usually ceramic PTC devices, which usually sets a surface temperature of between 110 and 160 ⁰ C, regardless of the boundary conditions, such as applied voltage, nominal resistance, air flow. Due to limitations in design and geometry, the attachment or construction of an electric auxiliary heater is quite expensive. In addition, the ceramic PTC devices are relatively heavy.

Conventional PTC ceramic heaters, which offer a very limited degree of freedom in the selection of a design form, use a fin member to improve the heat-radiating properties due to these design problems. Such a radiator is known for example from JP-B2-3274234. Here, a corrugated fin is combined with the heater of the PTC heater by a metal plate, and heat exchange between the PTC heater and air is performed by this corrugated fin. The generated heat of the PTC heater is thermally conducted through the metal plate to the corrugated fin and radiated from the corrugated fin to the air. The disadvantage here is that the temperature of the corrugated fin, which is in contact with the air flow, is significantly lower than the temperature of the PTC radiator.

For this reason, the direct heat transfer from the PTC radiator to the air flow is preferred. Thus, from DE 10 2004 027 687 A1 an electric heating device with a plurality of radiator plates, which are arranged parallel to each other to define an air duct between two adjacent radiator plates, one with an end face each

Radiator plate connected positive electrode element and connected to the other end of each radiator plate negative

Electrode element known. The radiator panels are for example, an electrically conductive resin in which an electrically conductive filler is mixed. In this case, the electrically conductive resin generally has a positive resistance-temperature characteristic in which the electrical resistance increases at a predetermined temperature or higher. The current flows from one electrode element through the radiator plates to the other electrode element. This eliminates the corrugated fins in this direct heat transfer.

Furthermore, embodiments with plastic PTC elements are known which by means of thereto, for example. Attached by gluing, the electrical

Contacting serving contact plates are connected, wherein the

Plastic PTC elements themselves form the heating grid directly. For example, DE 10 2004 045 668 A1 shows such electrically heatable

Plastic matrices, which may have, for example, a honeycomb structure or an air-foam structure. For an improved

Inlet and outlet of the stream contact means may be provided, for example in the form of combs with tines, which channels in the

Honeycomb structure are introduced by glued to the contact surfaces

Metal foils or by means of applied metal layers. The application of the metal layers, for example, by sputtering, the PVC process,

Arc evaporation or plating occur.

US 5,206,476 A discloses a PTC heater unit, which is arranged in the region of the outlets, wherein the PTC heater unit is formed by a polymer material having PTC properties, which has a plurality of rectangularly formed and arranged in a row air passages, which are traversed by air , On the top and bottom of the PTC element contact plates are provided for electrical contacting, so that the flow of current from the upper contact plate over the top of the PTC element through the individual webs to the bottom of the PTC element and then to the lower contact plate or vice versa. Such a heater unit leaves nothing to be desired.

Based on this prior art, it is an object of the invention to provide an improved electric heater or heater available. This object is achieved by an electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

According to the invention, an electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, is provided, with at least one heating element, which has at least one PTC element, which serves to heat a flowing medium, and the PTC element at least one row, consisting of a plurality of webs, which are connected to each other via at least one connecting portion, and the PTC element for current in and out at two opposite edge regions, which are arranged perpendicular or substantially perpendicular to the flow direction of the medium, electrically contacted is, wherein the connecting portion spaced from the electrically contacting edge regions is formed, and the spaced apart, outer ends of outer, outer webs of Stromein- or serve -out, ie there is no large-scale Stromein- or -ausleitung in or out the PTC element nt over the entire (closed) side surface. As a result of the outer webs, however, the current transfer region (contact plate and PTC element) flows around air or possibly another suitable medium, so that the PTC element does not de-regulate in this area and ensures the power supply of the inner region and thus the heating power can be. The medium is usually air, but the medium may be any other medium, in particular also a liquid, such as, in particular, oil, it being possible to provide corresponding properties and suitable measures for avoiding a flow of current through the medium. However, simplicity is referred to the medium only as air.

The fact that the heating element is arranged directly in the air flow, a high power density can be achieved in conjunction with a homogeneous temperature distribution over the entire heat transfer surface of the heating element. Furthermore, since no additional heat transfer elements, such as corrugated fins or the like, have to be provided in the air stream (but possibly can), the pressure drop is not unnecessarily increased.

The heating element preferably has at least three rows, in particular preferably exactly three rows, of webs which are separated from one another by connecting areas. Such a heating element has a relatively high stability.

Alternatively, however, a weight-saving design with only one centrally arranged connection region is possible. The webs emanating from this central connection region can be arranged in alignment with each other or offset in a gap.

The width of the webs is preferably 0.5 to 3.0 mm, particularly preferably 1 to 2.5 mm. Particularly preferably, the ridge widths of the inner and outer webs correspond.

The width of the connecting portion is preferably 0.5 to 3.0 mm, particularly preferably 1 to 2.5 mm. Particularly preferably, the width of the connecting regions corresponds to the width of the webs Particularly preferably, in at least one sectional plane perpendicular to the normal air flow direction, the width of a connecting region corresponds to the width of a web.

The width of the air channels formed between the webs is preferably 1 to 10 mm, particularly preferably 2 to 8 mm.

Particularly preferably, the connection region is formed at least in a sectional plane as a surface extending over the entire width of the heating element, and particularly preferably two mutually parallel connecting regions which are flat over the entire width of the heating element are provided.

The connecting region can be formed at least between two adjacent webs in a slope to the outer sides of the heating element arranged adjacent to the contact metal sheets. This allows a change in the direction of air flow and thus influences the flow direction of the air flowing out of the heater or heater. With a corresponding embodiment, for example, a directional or a diffuse air flow can be achieved.

The connecting portion is preferably disposed within a height range and spaced from the electrical contact, the height range being from a minimum height corresponding to the minimum width of a land or the minimum width of a joint region to a maximum height which is one third of the total height of the heating element corresponds, is enough.

Preferably, at least a part of the webs runs parallel to each other. Likewise, also or exclusively, at least a portion of the webs fan-like or otherwise at an angle not equal to 180 ° be arranged to each other, so that the air flow is fanned out or merged. The fanning or merging can take place in the height and / or width direction of the heating element.

In order to improve the mixing of the air, preferably at least a part of the webs, in particular of the inner webs, is formed such that these webs extend over only a part of the total depth of the heating element.

Particularly preferably, at least the outer webs are formed continuously in the depth direction, i. the outer air ducts preferably extend over the entire depth direction of the heating element.

Particularly preferably, the outer webs are shorter than the inner webs formed. Particularly preferably, the inner webs are formed at least twice, particularly preferably at least three times or four times as long as one of the outer webs.

Preferably, the connection region is zigzag-shaped or wave-shaped, with a web being provided on each mountain or under each valley. Such a configuration shortens the path of the current through the heating element something. Furthermore, a more uniform current distribution over the entire area of the heating element results. In the case of such a configuration of the connecting region, the width of the connecting region is preferably 40% to 60%, particularly preferably 50%, of the width of a web.

To increase the power density, the webs and / or the connecting regions may have a surface-enlarging structure. This structure may, for example, be formed by a plurality of grooves of any shape, nubs or ribs. The PTC elements are preferably made of plastic elements with PTC

Formed properties that are simpler and more flexible to produce than known ceramic PTC elements. The PTC element, especially in the case of a plastic PTC element, may be injection molded, extruded, sintered, or otherwise fabricated. The heating element preferably consists of a polymer, particularly preferably a polyolefin, with electrically conductive filling materials, in particular with carbon, in particular in the form of soot particles. However, other suitable materials may also be used.

Preferably, the plastic PTC element is partially, ie in the present case in the region of the ends of the outer webs, provided with at least one electrically conductive surface coating, hereinafter referred to as coating. The provision of an electrically conductive coating reduces the surface resistance and thus the contact resistance, wherein a direct electrical connection of electrically conductive particles in the PTC element takes place, and thus simplifies the power supply and / or -deritung, so that a large-area contact can be omitted, thereby reduce the cost and also the weight of the heater. The PTC elements are preferably provided with two electrically conductive coatings which are spatially separated from one another by the PTC element. Here, the coatings are arranged so that the PTC element flows through as large as possible and is thus heated accordingly. In order to prevent uneven heating, the thickness and thus the distance of the two coatings of the PTC element is formed as constant as possible. The current flow is preferably along the shortest path through the PTC element. In addition to an improvement of the current transition, a corresponding coating also results in an improvement of the heat transfer. The coating will preferably formed by silver, aluminum, copper or gold and corresponding alloys, other good current conducting materials are also possible. The coating can also be of multilayer design, for example by a copper layer applied to plastic.

The coating may preferably be by vapor deposition (e.g., PVC process, CVD process), plating, electrodeposition, and / or thermal spraying. Other methods are also possible. Likewise, an electrically conductive film can be glued, wherein the film can also be designed to be self-adhesive.

The contact plate and / or the heating element can be connected to each other by means of mechanical joining, for example by means of compression, for example in a frame, or a biasing spring which is inserted into the frame with the other components. Also, a bonding is possible. In this case, the adhesive can be applied and cured in any desired manner. The adhesive may form a continuous layer, but preferably contact points for electrical contacting are provided, on which the parts to be connected are in direct contact with each other. In particular, in this case, the use of a low-cost, insulating adhesive is possible.

A particularly simple electrical contact between heating element and contact plate is possible in that slots are formed in the contact plate, in which elongated outer webs or the outer ends of spacers are inserted and fixed therein.

The slots may be double-T-shaped, so that tongues are provided on both sides in the depth direction of the heating element, which bear resiliently against the side surfaces of the webs or spacers and hold the same. In a staggered arrangement of extended trained webs or spacers can be mounted on both sides of the contact plate heating elements on the same, so that a very simple and compact construction of a heater or auxiliary heater, for example. For two heating zones is possible.

The contact sheets preferably have a thickness of 0.3 to 3.0 mm, in particular 0.5 to 2.0 mm. They are preferably made of aluminum, copper, a copper-zinc alloy, optionally with silicon, or steel, in particular spring steel. However, other electrically conductive materials are possible.

For reasons of short-circuit safety in the motor vehicle, the outer contact plates are preferably connected to the minus pole and / or the inner contact plates are connected to the plus pole.

One or more such electrical heaters or heaters are preferably used in a motor vehicle heating or air conditioning system. In this case, a corresponding arrangement of PTC elements both in the region of the heater, i. In particular, in the housing of an air conditioner, used as a heater and in the area of the air ducts just before the vents, where the PTC elements generate additional heat when needed "on site".

In the following the invention with reference to several embodiments with reference to the drawings will be explained in detail. Show it:

1 is a front view of an electric auxiliary heater according to the first embodiment,

2 is a fragmentary enlarged view of the auxiliary heater of FIG. 1 to illustrate the flow of current, 3 is a perspective view of an electric auxiliary heater according to the second embodiment,

4 is a fragmentary enlarged view of the auxiliary heater of Fig. 3,

5 is a perspective view of an electric auxiliary heater according to the third embodiment,

6 is a fragmentary enlarged view of the auxiliary heater of Fig. 5,

7 is a perspective view of an electric auxiliary heater according to the fourth embodiment,

8 is a fragmentary enlarged view of the auxiliary heater of Fig. 7,

9 is a perspective view of an electric auxiliary heater according to the fifth embodiment,

10 is a fragmentary enlarged view of the auxiliary heater of Fig. 9,

11 is a perspective view of an electric auxiliary heater according to the sixth embodiment,

12 is a perspective view of an electric auxiliary heater according to the seventh embodiment, 13 is a fragmentary enlarged view of the auxiliary heater of Fig. 12,

14 is a perspective view of an electric auxiliary heater according to a variant of the seventh embodiment,

15 is a perspective view of an electric auxiliary heater according to another variant of the seventh embodiment,

16 is a perspective view of an electric auxiliary heater according to the eighth embodiment,

17 is a perspective view of an electric auxiliary heater according to the ninth embodiment,

18 is a perspective view of an electric auxiliary heater according to the tenth embodiment,

19 is a section through the heater of FIG. 18,

20 is a perspective view of an electric auxiliary heater according to the eleventh embodiment,

21 is a section through the heater of FIG. 20,

22 is a perspective view of an electric auxiliary heater according to the twelfth embodiment,

FIG. 23 is a fragmentary enlarged view of the auxiliary heater of FIG. 22; FIG. FIG. 24 shows an edge region of an auxiliary heater according to the first exemplary embodiment, FIG.

FIG. 25 shows a schematic representation of the edge region of FIG. 24 in the case of a clamped auxiliary heater, FIG.

Fig. 26 is a schematic illustration of the edge portion of Fig. 24im

Trap of a plugged auxiliary heater,

Fig. 27 is a schematic representation of the edge region of Fig. 24 in the case of an auxiliary heater, wherein the contact plate with the

Ends of the outer webs is encapsulated,

28 is a perspective view of an auxiliary heater with four PTC

Heating elements with central connection area,

Fig. 29 is a fragmentary enlarged view of the auxiliary heater of Fig. 28, and

30 is a fragmentary, enlarged view of an additional heater according to a variant of the auxiliary heater of Fig. 28.

An electric heater 1 with a depth of 25 mm for an automotive air conditioning system (not shown), according to the first

Embodiment a block-like design and with a plurality of continuous in the air flow direction, parallel to each other

Openings formed heating element 2, which is arranged between two of the electrical contacting of the heating element serving contact plates 3. The heating element 2 consists of a plastic with PTC properties, in the present case of a polyolefin with soot particles, for which reason reference is also made below to the heating element 2 as a PTC element. In the present case, the PTC element is produced by means of spraying; alternatively, other production methods, such as are known in particular from the production of plastics, are possible, such as, for example, extrusion or sintering. As an alternative to a plastic PTC element, another suitable material with PTC properties can also be used. The contact plates 3 are electrically highly conductive metal sheets, which are connected to a power source (not shown).

The contact plates 3 forming the electrodes are in the present case steel sheets with a thickness of 0.5 mm.

According to the first exemplary embodiment, the auxiliary heater 1 is arranged downstream of the heater in the airflow flowing through the motor vehicle air-conditioning system, but the auxiliary heater can also be arranged elsewhere in an air duct, for example shortly before the outflows, through which the air enters the vehicle interior flows. In this case, the air to be heated is passed both through the openings in the heating element 2.

The heating element 2 in the present case has three rows of webs 4 arranged parallel to one another and with respect to the contact sheets 3, namely upper and lower outer webs 4a and central, inner webs 4b, which are each provided with air passages 5, namely outer air passages 5a between the outer webs 4a and inner air passages 5b between the inner webs 4b, are separated from each other and offset with respect to the adjacent web row gap to each other.

Between the webs 4a and 4b connecting regions 6 are formed, via which a transverse distribution of the current flow between the webs 4th can be done. The two connection regions 6 are arranged parallel to one another and to the contact plates 3 and each have a thickness which corresponds to the width of the webs 4. The connecting regions 6 are each closer to the outside of the heating element 2, that is arranged at the corresponding contact plate 3, as at the other connection region 6, that is, the outer webs 4a are shorter than the inner webs 4b.

The width of the webs 4 of the individual rows is the same here and is 2 mm. The width of the air channels 5, which are formed between the webs 4, is slightly larger than the width of the webs 4 and in the present case is 2.5 mm. The length of the outer webs 4a, which corresponds to the distance of the contact plates 3 from the connection region 5, is presently 3 mm, the length of the inner webs 4b is in the present case 30 mm.

The air flows through the heater 1 in the area of all the openings formed by the webs 4a and 4b, i. Also, the relatively small openings in the region of the outer sides, on which the contact plates 3 are arranged, are traversed by air and thereby cooled.

The current flow takes place, as shown in Fig. 2 by arrows, via the upper contact plate 3 to the upper, outer webs 4a and then to the connecting portion 6. As a result of the connecting portion 6 between the individual webs 4, the power is distributed as needed to all inner webs 4b. Subsequently, the current passes via the lower connection region 6 to the lower, outer webs 4 a to the lower contact plate. 3

At high current densities, the PTC element heats up in the corresponding one

Range and regulated as a result of heating, so that less heat is generated in the corresponding area. In addition, the electric increases

Resistance in the appropriate area, so that the current is one seeks another way, if possible. However, since the heat generated in the PTC element in this area due to the air flow through the outer air channels 5a, ie between the connection region and the contact plate 3, derived and also on the connection area, if necessary, a Distribution of the current over the entire width of the PTC element is made possible, especially in the central region of the heating element 2 is a very needs-based heat generation.

The power densities of the surface of the individual webs 4 of the PTC element are presently about 0.45 watts / cm ² in an air flow with an air volume of more than 1 kg / min, and an air inlet temperature in the heater 1 of less than 40 ⁰ C. The power densities under corresponding conditions based on the volume of the entire PTC element in the present case is about 4.0 watts / cm ³ .

The second exemplary embodiment, which is illustrated in FIGS. 3 and 4, does not correspond explicitly to the first exemplary embodiment, so that identical or equivalent components or regions of components are provided with the same reference numerals as in the first exemplary embodiment.

In contrast to the first exemplary embodiment, in the auxiliary heater 1 according to the second exemplary embodiment, the webs 4a and 4b are not arranged on a gap, but are aligned with one another, so that a grid-like structure is produced in the contact plate-side outer regions of the heating element 2. Furthermore, the transition to the connecting regions 6, in contrast to the first embodiment, is rounded and not angular. The air flow through the heater 1 is shown schematically in FIG. As indicated here, a flow through the outer air channels 5a is again provided in this embodiment in order to To cool the Stromeinleit- and -ausleitbereich in or out of the outer webs 4a.

Figures 5 and 6 show a third embodiment of an auxiliary heater 1, which corresponds in principle to the two embodiments described above, so that the same or equivalent components or areas of components are provided with the same reference numerals as in the first embodiment. In contrast to the previous embodiments, however, the distribution of the inner and outer webs 4b and 4a is different, since the widths b of the outer air ducts 5a is different from the widths a of the inner air ducts 5b, wherein in the present case, the width b of the outer air ducts greater than that Width a of the inner air channels is (see Fig. 6). The transitions of the webs 4a and 4b to the connecting portions 6 is rounded in accordance with the second embodiment.

According to a variant of the third embodiment not shown in the drawing also varies the distance of the inner and the outer webs across the width of the auxiliary heater, wherein in the present case, the distance in the outer regions is slightly less than in the central region. Any other variations in the distance of the inner and / or outer webs from each other are possible.

FIGS. 7 and 8 show a further, fourth exemplary embodiment of an auxiliary heater 1 according to the invention. In this case, the transition regions between the webs 4 and the connecting regions 6 are designed to be completely rounded, ie the individual regions flow into one another in a flowing manner. Further, the end portions are chamfered and thereby an improved flow path in the air inlet region is possible. In the present case, in turn, the outer and inner webs 4a and 4b are aligned with each other, but also an offset can be provided. The fifth exemplary embodiment of an auxiliary heater 1 illustrated in FIGS. 9 and 10 substantially corresponds to the first exemplary embodiment, so that identical or equivalent components or regions of components are provided with the same reference numerals as in the first exemplary embodiment.

In accordance with the fifth exemplary embodiment, each of the two connection regions 6-in contrast to the first exemplary embodiment-runs in a zig-zag shape with presently right angles in the region of the branching of the inner and outer webs 4b and 4a. The width of the webs 4 is constant. The width of the connecting portion 6 is presently about half as large as the width of the webs 4. The two connecting portions 6 are - according to the first embodiment - respectively arranged in the vicinity of the corresponding contact plate 3, but between the connecting portion 6 and the contact plate 3 a A plurality of outer air channels for cooling the outer webs 4a is provided.

Instead of right angles in the zig-zag-shaped connection region, as provided according to the fifth embodiment, also blunt or more acute angles can be provided. Likewise, for example, a wave-shaped course of the connection region can be provided. any

Mixed forms are possible, as well as variations in the spacing of the webs of a row. It makes sense, however, an arrangement of the webs of two adjacent rows on the gap.

The sixth exemplary embodiment of an auxiliary heater 1 illustrated in FIG. 11 substantially corresponds to the second exemplary embodiment, so that identical or equivalent components or regions of components are provided with the same reference numerals as in the second exemplary embodiment. In contrast to the second embodiment, the inner Webs 4b formed in the depth direction of the heating element 2 is not over the entire depth, but each only over half of the depth, wherein adjacent webs 4b are arranged offset, ie a luftanströmseitiger web 4b ¹ , which extends from the air inlet side to the center of the heating element 2 , is disposed in the center of the heating element 2 (viewed in the depth direction) adjacent an air downstream web 4b "extending from the center of the heating element 2 to the air exit side of the heating element 2. The outer webs 4a are formed continuously in the depth direction and over the Width of the heating element at equidistant intervals and each aligned with an air-upstream web 4b ¹ and a luftabströmseitigen web 4b "arranged, ie, the outer air channels 5a are formed continuously. In principle, however, a configuration, as provided in the inner webs of the present embodiment, possible.

As a result of the staggered, non-continuous arrangement of the inner webs 4b, there is a better air mixing of the air flowing through this region of the heating element 2.

According to the sixth embodiment, the lengths of the air-upstream and downstream edges correspond to each other, and the sum of the ridge lengths gives the length of an outer ridge. However, this is not necessarily the case. In order to allow better air mixing, the webs may be spaced apart in the depth direction, so that the sum of the web lengths of the air-upstream and downstream webs is smaller than the length of an outer web, but this reduces the heating power in relation to the overall depth. Likewise, a (short) overlap would be possible. Furthermore, the air upstream and downstream air webs need not be the same length. Likewise, variations of the individual web lengths over the width of the heating element are possible. Figures 12 and 13 show a seventh embodiment of an additional heater 1 according to the invention, wherein the same or equivalent components or areas of components with the same reference numerals as in the first embodiment are provided.

The sectional profile in a section perpendicular to the (normal) air flow direction centered by the heating element 2 according to the seventh embodiment corresponds in this case to a section through the heating element according to the second embodiment, but missing the rounding. As a result of an oblique course of the connecting regions 6, which run alternately slightly upwards and downwards, a clear offset of the individual connecting regions 6, which originate from a web 4, results on the air inlet side and the air outlet side. As is apparent from FIGS. 12 and 13, the maximum offset on the air inlet side and the air outlet side corresponds approximately to the width of a web, which in the present case also corresponds to the width of the connecting regions.

Figures 14 and 15 show variants of the seventh embodiment. In this case, according to the variant shown in FIG. 14, the connecting region 6 is widened. The maximum offset on the air inlet side and the air outlet side, as shown in Fig. 14, is greater than the width of a land, but slightly smaller than the width of the joint areas. According to the variant of FIG. 15, the width of the webs 4 and the connecting region 6 is the same. The maximum offset is about twice the width of a web.

Fig. 16 shows a heater 1 according to the eighth embodiment. Here, the arrangement of the webs 4 and connecting portions 6 on the air inlet side corresponds to that of the second embodiment, However, the rounding between the webs and connecting portions are formed smaller. As can be seen from FIG. 16, the connecting regions 6 extend upwards or downwards, so that again an offset results on the air outlet side. In the present case, the connecting regions between two adjacent webs 4 run parallel to one another, but another embodiment is also possible.

FIG. 17 shows a further heater 1, which has different angles of inclination of the connecting regions 6, so that the cross-sectional areas of the individual air passages 5 vary greatly. In the case of the maximum offset of a portion of the connecting portions 6, the same extends up to about one third of the height of the heating element 2 zoom.

Figures 18 and 19 show a tenth embodiment of an auxiliary heater 1, which parallel to each other and to the contact plates 3 extending connecting portions 6 but different orientations of

Webs 4, wherein the webs 4 - apart from the two the

Outside forming webs - are aligned fan-shaped.

The outer and inner webs are aligned in the present case. In order to avoid too large a distance between the individual webs 4, in each case between the web forming the outside and the adjacent web

Jetty provided in its depth significantly shortened jetty.

Figures 20 and 21 show an eleventh embodiment of a combination of the two previous embodiments, so that the heater

1 both inclined connecting portions 6 with different, over the

Width of the heating element 2 varying inclination angles and different orientations of the webs 4, wherein the webs 4 - apart from the two outer sides forming webs - are aligned fan-shaped. The outer and inner webs are aligned in the present case. By this arrangement can - depending on Flow direction of the air - fanned out or bundled. Correspondingly, the outer air ducts 5a also expand or narrow.

Figures 22 and 23 show a tenth embodiment, which substantially corresponds to the second embodiment. In contrast to the second embodiment, however, a plurality of U-shaped grooves running in the depth direction are provided in the region of the webs 4, which enlarge the surface, so that the power density can be increased.

The provision of corresponding or similar profilings for enlarging the surface is also possible with the other exemplary embodiments described above. In the present case, the connection regions 6 are formed without such structures, but a corresponding configuration can also be made in this region.

Any other arrangements of the webs and connecting regions, different from the previously described embodiments, are possible. In this case, however, it is preferred that each of the connection regions is designed to extend in a continuous line in at least one sectional plane, or at least is arranged within a certain height range. The height range in this case extends from a minimum height, which corresponds to the minimum web width or the minimum width of the connecting region, to a maximum height, which corresponds to one third of the total height of the heating element, in particular up to a height which corresponds to a quarter of the total height of the heating element ,

The connection of the contact plates 3 to the ends of the outer webs 4a can be done in any way. For example, the contact sheets 3 can be clamped, as shown schematically in FIG. For this are

Heating element and contact plates arranged in a frame and the required force for clamping the elements can, for example, be applied by a spring. Alternatively or in conjunction therewith, clip connections in the form of spring arms, which are formed on the contact plate, and projections or openings, which are formed on the heating element, may be provided for fixing the elements together.

Alternatively - or in conjunction with a terminal - heating element and contact plate 3 can be glued, as shown schematically in Fig. 26. In the case of using an electrically insulating adhesive, the same is displaced in the context of compression from the gap between the contact plate and heating element and collects laterally adjacent to the end of the outer web 4a in the throat between contact plate and web.

It is also possible to encapsulate the contact sheets 3 with the PTC material, with the contact sheets 3 preferably having corresponding openings, such as slots and / or bores, in order to be securely held by means of the material which has penetrated through the openings as a result of positive locking ( see Fig. 27).

In order to improve the current introduction and discharge, appropriate coatings may be provided on areas of the surface of the heating element.

In FIGS. 28 and 29, a variant of an auxiliary heater 1, comprising four independently switchable heating elements 2, with only one centrally arranged connecting region 6, extends from the webs which are aligned with each other. In the present case, the webs of adjacent heating elements 2 are aligned with each other. The individual heating elements are present alternately arranged with contact plates 3 braced in a frame (not shown). Alternatively, they can be glued, for example or otherwise connected to each other to form a sufficient contact surface.

FIG. 30 shows a variant of the exemplary embodiment of FIG. 28, according to which webs, which are formed integrally on a central connecting web, are each arranged offset from one another in a gap.

Claims

Patent claims

1. An electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, having at least one heating element (2) having at least one PTC element, which serves to heat a flowing medium, and the PTC element at least one row consisting of a plurality of webs (4), which are interconnected via at least one connecting portion (6), and the PTC element for current in and out at two opposite edge regions, which are arranged perpendicular or substantially perpendicular to the flow direction of the medium are electrically contacted, characterized in that the connecting region (6) spaced from the electrically contacting edge regions is formed, and the spaced, outer ends of the outer side, outer webs (4a) of the Stromein- or serve -out.

2. Electric heater or heater according to claim 1, characterized in that the heating element (2) has at least three rows of webs (4), which are separated by connecting regions (6).

3. Electric heater or heater according to claim 2, characterized in that the heating element (2) has exactly three rows of webs (4) which are separated by two connecting portions (6).

4. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the width of the webs (4) is 0.5 to 3.0 mm.

5. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the width of the connecting region (6) is 0.5 to 3.0 mm.

6. Electric heater or heater according to one of the preceding claims, characterized in that in at least one

Section plane perpendicular to the normal air flow direction corresponds to the width of a connecting portion of the width of a web.

7. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the air channel width between the webs (4) is 1 to 10 mm.

8. Electrical heater or auxiliary heater according to one of the preceding claims, characterized in that the connecting region (6) at least in a sectional plane as a over the entire width of the

Heating element (2) is formed extending surface.

9. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the connecting region (6) at least between two adjacent webs (4) in a slope to the outside of the contact plates (3) arranged outside of the heating element (2) is formed.

10. Electric heater or heater according to claim 9, characterized in that the connection region (6) within a

Height range and spaced from the electrical contact, wherein the height range of a minimum height, which corresponds to the minimum width of a web (4) or the minimum width of a connecting portion (6), up to a maximum height, which is one third of the total height of Heating element (2) corresponds, is sufficient.

11. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that at least part of the webs (4) extends parallel to each other.

12. An electric heater or auxiliary heater according to one of the preceding claims, characterized in that at least a part of the webs (4) is arranged like a fan.

13. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that at least part of the webs (4), in particular of the inner webs (4b), extends over only a part of the total depth of the heating element (2).

14. Electric heater or heater according to claim 13, characterized in that the outer webs (4a) are formed continuously in the depth direction.

15. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the connection region (6) is formed zig-zag or wavy, with a web (4) is provided on each mountain or under each valley.

16. Electric heater or heater according to claim 15, characterized in that the width of the connecting region (6) 40% to

60%, in particular 50%, the width of a web (4) is.

17. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the webs (4) and / or the connecting regions (6) have a surface-enlarging structure.

18. Electric heater or heater according to one of the preceding claims, characterized in that the heating element (2) made of a polymer, in particular a polyolefin, with electrically conductive

Filling materials, in particular with carbon, in particular in the form of soot particles.

19. Motor vehicle heating or air conditioning characterized by at least one electric heater or heater (1) according to one of the preceding claims.