EP1933598B1 - Electrical heater or supplementary heater, in particular for a heating or air conditioning assembly of a vehicle - Google Patents

Description

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

In low-consumption vehicles, an additional heating power is required to heat the passenger compartment as well as to quickly remove a fogging (ice or water), in particular on the windshield, due to the low waste heat supply. 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 provide additional heating in the form of PTC heating elements, which is usually at Ceramic PTC components, which usually sets a surface temperature of between 110 and 160 ° 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 for example from the JP-B2-3274234 known. 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. So is out of the DE 10 2004 027 687 A1 an electric heater having a plurality of heater plates arranged in parallel with each other to define an air passage between two adjacent heater plates, a positive electrode element connected to an end face of each heater plate, and a negative electrode element connected to the other end face of each heater plate. The radiator panels are, for example, an electrically conductive resin, in which an electrical 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 are connected thereto by means of, for example, by gluing, the electrical contacting serving contact plates are connected, wherein the plastic PTC elements themselves form the heating grid directly. For example, the shows DE 10 2004 045 668 A1 Such electrically heatable plastic matrices, which may have, for example, a honeycomb structure or a foam structure through which air can flow. For an improved introduction and discharge of the current contact means may be provided, for example in the form of combs with prongs, which are inserted into channels of the honeycomb structure, by means of bonded to the contact surfaces metal foils or by means of applied metal layers. The application of the metal layers can be done for example by sputtering, the PVC process, arc evaporation or electroplating.

The US 5,206,476 A discloses a PTC heater unit disposed in the region of the outlets, wherein the PTC heater unit is formed by a polymer material with 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 otherwise done around. Such a heater unit leaves nothing to be desired.

The FR 2 859 866 A1 discloses a heater having a honeycomb-like heating element which is arranged electrolytically between connection elements.

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.

The object is achieved with the features of claim 1.

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 outer and inner webs, wherein the outer webs are connected to the inner webs via at least one connecting portion with each other, and the PTC element for Stromin- or -ausleitung at two opposite edge regions, the vertical or substantially are arranged perpendicular to the flow direction of the medium, is electrically contacted, wherein the connecting portion spaced from the electrically contacting edge regions is formed, and the spaced apart, outer ends outside arranged, outer webs of Stromein- or serve -out, all webs pa are arranged parallel to each other and the outer webs are aligned with the inner webs, ie there is no large-scale Stromein- or - discharge into or out of the PTC element over the entire (closed) side surface. In consequence of the outer webs, however, is the Current flow area (contact plate or similar and PTC element) flows around air or possibly another suitable medium, so that the PTC element in this area does not worsen and the power supply to the inner area and thus the heating power can be ensured. The medium is usually air, however, the medium may also be any other medium, in particular a liquid, such as, in particular, oil, where appropriate appropriate properties and suitable measures to avoid a flow of current through the medium are provided , 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, the pressure drop, since no additional heat transfer elements, such as corrugated fins or the like, must be provided in the air flow (but possibly can), 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 formed by plastic elements with PTC properties, which are easier 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 "on the spot" when needed.

Fig. 1

eine Frontansicht eines elektrischen Zuheizers gemäß dem ersten Ausführungsbeispiel,

Fig. 2

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 1 zur Verdeutlichung des Stromflusses,

Fig. 3

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem zweiten Ausführungsbeispiel,

Fig. 4

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 3,

Fig. 5

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem dritten Ausführungsbeispiel,

Fig. 6

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 5,

Fig. 7

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem vierten Ausführungsbeispiel,

Fig. 8

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 7,

Fig. 9

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem fünften Ausführungsbeispiel,

Fig. 10

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 9,

Fig. 11

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem sechsten Ausführungsbeispiel,

Fig. 12

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem siebten Ausführungsbeispiel,

Fig. 13

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 12,

Fig. 14

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß einer Variante des siebten Ausführungsbeispiels,

Fig. 15

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß einer weiteren Variante des siebten Ausführungsbeispiels,

Fig. 16

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem achten Ausführungsbeispiel,

Fig. 17

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem neunten Ausführungsbeispiel,

Fig. 18

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem zehnten Ausführungsbeispiel,

Fig. 19

einen Schnitt durch den Zuheizer von Fig. 18,

Fig. 20

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem elften Ausführungsbeispiel,

Fig. 21

einen Schnitt durch den Zuheizer von Fig. 20,

Fig. 22

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem zwölften Ausführungsbeispiel,

Fig. 23

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 22,

Fig. 24

einen Randbereich eines Zuheizers gemäß dem ersten Ausführungsbeispiel,

Fig. 25

eine schematische Darstellung des Randbereichs von Fig. 24 im Falle eines geklemmten Zuheizers,

Fig. 26

eine schematische Darstellung des Randbereichs von Fig. 24 im Falle eines gekleben Zuheizers,

Fig. 27

eine schematische Darstellung des Randbereichs von Fig. 24 im Falle eines Zuheizers, bei dem das Kontaktblech mit den Enden der äußeren Stege umspritzt ist,

Fig. 28

eine perspektivische Darstellung eines Zuheizers mit vier PTC-Heizelementen mit zentralem Verbindungsbereich,

Fig. 29

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 28, und

Fig. 30

eine ausschnittsweise, vergrößerte Darstellung eines Zuheizers gemäß einer Variante des Zuheizers von Fig. 28.

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

Fig. 1

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

Fig. 2

a fragmentary, enlarged view of the auxiliary heater of Fig. 1 to clarify the current flow,

Fig. 3

a perspective view of an electric heater according to the second embodiment,

Fig. 4

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

Fig. 5

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

Fig. 6

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

Fig. 7

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

Fig. 8

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

Fig. 9

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

Fig. 10

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

Fig. 11

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

Fig. 12

a perspective view of an electric heater according to the seventh embodiment,

Fig. 13

a fragmentary, enlarged view of the auxiliary heater of Fig. 12 .

Fig. 14

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

Fig. 15

a perspective view of an electric heater according to a further variant of the seventh embodiment,

Fig. 16

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

Fig. 17

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

Fig. 18

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

Fig. 19

a section through the heater of Fig. 18 .

Fig. 20

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

Fig. 21

a section through the heater of Fig. 20 .

Fig. 22

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

Fig. 23

a fragmentary, enlarged view of the auxiliary heater of Fig. 22 .

Fig. 24

an edge portion of an auxiliary heater according to the first embodiment,

Fig. 25

a schematic representation of the edge region of Fig. 24 in the case of a clamped auxiliary heater,

Fig. 26

a schematic representation of the edge region of Fig. 24 in the case of a plugged auxiliary heater,

Fig. 27

a schematic representation of the edge region of Fig. 24 in the case of an auxiliary heater, in which the contact plate is overmolded with the ends of the outer webs,

Fig. 28

a perspective view of an additional heater with four PTC heating elements with central connection area,

Fig. 29

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

Fig. 30

a detail, 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 a power-conditioning system (not shown) has, according to the first embodiment, a block-shaped and formed with a plurality of continuous in the air flow direction, mutually parallel openings formed heating element 2, which between two of the electrical Contacting the heating element serving contact plates 3 is arranged.

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 in Fig. 2 represented 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 current 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 area and regulates as a result of heating, so that less heat is generated in the corresponding area. In addition, the electrical resistance in the corresponding area increases, so that the current is a 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 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 into the heater 1 of less than 40 ° C. The power densities under appropriate conditions based on the volume of the entire PTC element is presently about 4.0 watts / cm ³ .

The second embodiment, in the FIGS. 3 and 4 is not shown, so far as not explicitly mentioned in the first embodiment, so that the same or equivalent components or areas of components with the same reference numerals as in the first embodiment are provided.

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 Fig. 3 shown. 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.

FIGS. 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, moreover, the distance between the inner and the outer webs varies 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 embodiment of an auxiliary heater according to the invention 1. Here, the transition regions between the webs 4 and the connecting portions 6 are formed very fully rounded, ie the individual areas are flowing into each other. 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, in the FIGS. 9 and 10 illustrated embodiment of an additional heater 1 substantially corresponds to the first embodiment, so that the same or equivalent components or areas of components are provided with the same reference numerals as in the first 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 hybrid forms are possible, as well as variations in the spacing of the ridges of a row. It makes sense, however, an arrangement of the webs of two adjacent rows on the gap.

The sixth, in Fig. 11 illustrated embodiment of an auxiliary heater 1 substantially corresponds to the second embodiment, so that the same or equivalent components or areas of components are provided with the same reference numerals as in the second 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 ', 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 in equidistant intervals and each aligned with a luftanströmseitigen web 4b 'or 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 inventive heater 1, 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. The maximum offset on the air inlet side and the air outlet side corresponds to how out Figures 12 and 13 can be seen, approximately the width of a web, which in the present case also corresponds to the width of the connecting portions.

The Figures 14 and 15 show variants of the seventh embodiment. Here, according to the in Fig. 14 variant of the connecting portion 6 shown widened formed. The maximum offset on the air inlet side and the air outlet side is how out Fig. 14 larger 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 portion 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. How out Fig. 16 can be seen, the connecting portions 6 extend upwards or downwards, so that in turn results in an offset 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 portions 6, so that the cross-sectional areas of the individual air ducts 5 vary widely. 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.

The FIGS. 18 and 19 show a tenth embodiment of an auxiliary heater 1, which parallel to each other and the contact plates 3 extending connecting portions 6 but 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. In order to avoid too great a distance between the individual webs 4, a web which is significantly shortened in its depth is provided in each case between the web forming the outside and the adjacent web.

The FIGS. 20 and 21 show an eleventh embodiment, a combination of the two previous embodiments, so that the heater 1 both inclined connecting portions 6 with different, varying over the width of the heating element 2 inclination angles and different orientations of the 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. 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.

The 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 connection 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 in Fig. 25 shown schematically. For this purpose, heating element and contact plates are 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 in Fig. 26 shown schematically. 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 ( please refer 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 the FIGS. 28 and 29 is a variant of an auxiliary heater 1, comprising four independently switchable heating elements 2, with only one centrally arranged connection region 6 extending from the aligned webs. 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 embodiment of Fig. 28 , According to, which are arranged offset to one another at a central connecting web integrally formed webs each gap.

Claims (17)

1. An electric heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, comprising at least one heating element (2) that includes at least one PTC element used to heat a flowing medium, and the PTC element includes at least one row comprising a plurality of outer and inner webs (4, 4a, 4b), the outer webs (4a) being connected to the inner webs (4b) via at least one connecting region (6), and the PTC element being electrically contacted for conducting power in or out at two mutually opposing edge regions, which are arranged perpendicularly, or substantially perpendicularly, to the flow direction of the medium, the connecting region (6) being spaced from the electrically contacted edge regions, and the mutually spaced outer ends of outer webs (4a) arranged on the outside being used to conduct power in or out, characterized in that all the webs (4) are arranged parallel to each other and the outer webs (4a) are aligned with the inner webs (4b).
2. The electric heater or auxiliary heater according to claim 1, characterized in that the heating element (2) comprises at least three rows of webs (4), which are separated from each other by connecting regions (6).
3. The electric heater or auxiliary heater according to claim 2, characterized in that the heating element (2) comprises exactly three rows of webs (4), which are separated from each other by two connecting regions (6).
4. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the widths of the webs (4) range between 0,5 and 3,0 mm.
5. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the widths of the connecting regions (6) range between 0,5 and 3,0 mm.
6. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the width of a connecting region corresponds to the width of a web in at least one cutting plane perpendicular to the normal air flow direction.
7. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the air duct widths between the webs (4) range between 1 and 10 mm.
8. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the connecting region (6) is designed at least in one cutting plane as an area extending over the entire width of the heating element (2).
9. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the connecting region (6) is designed at least between two neighboring webs (4) at an incline to the outer sides of the heating element (2) that are arranged adjacent to the contact plates (3).
10. An electric heater or auxiliary heater according to claim 9, characterized in that the connecting region (6) is arranged within a height range and spaced from the electrical contacting, the height range being from a minimum height, which corresponds to the minimum width of a web (4) or the minimum width of a connecting region (6), to a maximum height, which corresponds to one third of the overall height of the heating element (2).
11. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that at least some of the webs (4), in particular the inner webs (4b), extend only over a portion of the overall depth of the heating element (2).
12. The electric heater or auxiliary heater according to claim 11, characterized in that the outer webs (4a) are designed to be continuous in the depth direction.
13. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the connecting region (6) is designed to be zigzag-shaped or undulated, a respective web (4) being provided on each peak and beneath each valley.
14. The electric heater or auxiliary heater according to claim 13, characterized in that the width of the connecting region (6) is 40% to 60%, in particular 50%, of the width of a web (4).
15. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the webs (4) and/or the connecting regions (6) have a surface-increasing structure.
16. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the heating element (2) is composed of a polymer, in particular a polyolefin, comprising electrically conductive filler materials, in particular carbon, in particular in the form of soot particles.
17. A motor vehicle heating or air conditioning system, characterized by at least one electric heater or auxiliary heater (1) according to any one of the preceding claims.

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