EP1933597A1 - Electrical heater or supplementary heater, in particular for a heating or air conditioning assembly of a vehicle - Google Patents

Abstract

The heater (1) has at least one heating element (2) with at least one positive temperature coefficient or PTC element for heating a fluid with at least one row of bridges (4) joined by at least one connection region (6). The PTC element is contacted via contact plates (3) at opposite edges for current input or output. At least directly adjacent areas of the contact surfaces of the element and plate bound an outer air channel, whereby a number of current input and output regions are provided that are separated the outer air channels. An independent claim is also included for a motor vehicle heating or air conditioning system with at least one inventive heater.

Description

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, 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 an additional heating in Form of PTC heating elements, which are usually 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 ceramic PTC 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.

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 connection region, and the PTC element for current in and out at two opposite edge regions, which are perpendicular or substantially perpendicular to the flow direction of the medium, via contact plates is electrically contacted, wherein at least one directly adjacent portion of the heating element contacting surface of the contact plate and at least one directly adjacent portion of the contact sheet contacting surface of the heating element defines an outer air channel, which through the heating element and the Kontaktblec h is formed, and a plurality of Stromein- or -leitleitbereiche is provided, which are separated from each other by said outer air channels. By providing external air passages, the electrical contact region is cooled, so that the power density of the heating element can be increased. A Abregeln the heating element as a result of too high a temperature in the edge region can be avoided. If necessary, the air can be directed into the outer air ducts in a targeted manner in order to increase the cooling of the edge area and thereby increase the overall performance of the heating element.

More preferably, the connecting portion is formed spaced from the electrically contacting edge portions, and the spaced-apart outer ends of the outer-side outer webs are for flow-in and out-routing, i. there is no large-scale Stromein- or -ausleitung in or out of the PTC element over the entire (closed) side surface. In this case, the connection region preferably forms part of the boundary of the outer air duct. As a result of the outer webs, however, the current transition region (contact plate or the like and PTC element) flows around air or possibly another suitable medium, so that the PTC element in this area does not de-energize and the power supply of the inner region 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 connection region preferably forms the electrically contacting edge region, and between the contact plate and the connection region, spacers are preferably provided which separate the outer air channels from one another. In such an embodiment, at least one Surrounding area of air, which is adjacent to the electrically contacted edge regions of the heating element, ie the heat generated here can be dissipated and a Abregeln the heating element in the corresponding area due to overheating can be prevented. Influencing the air distribution to the individual air ducts through the heating element is possible.

The spacers may be formed directly on the contact plate. They are for example by means of forming, e.g. Embossing, made. Alternatively, spacers can be mounted as a spacer on the contact plate, for example. By means of soldering.

The spacers are electrically conductive to allow for power in and out of the heating element.

However, the spacers are particularly preferably formed from PTC material, and particularly preferably they are formed integrally with the heating element, wherein they are preferably formed by luftumsströmte, outer webs.

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.

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.

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 connection region is preferably arranged within a height range and spaced from the electrical contact, wherein the Height range from a minimum height which corresponds to the minimum width of a web or the minimum width of a connecting portion, to a maximum height which corresponds to one third of the total height of the heating element is sufficient.

Preferably, at least a part of the webs runs parallel to each other. Likewise, at least some of the webs may be arranged in a fan-like manner or otherwise at an angle not equal to 180 ° to one another, even or excluding them, so that the air flow is fanned out or brought together. 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 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 an offset arrangement of the elongated webs or spacers heating elements can be attached to the same from both sides of the contact plate, so that a very simple and compact construction of a heater or auxiliary heater, for example, is possible for two heating zones.

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, whereby 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 Electricity transfer has a corresponding coating and an improvement in the heat transfer result. The coating is 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.

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".

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

eine ausschnittsweise, vergrößerte Darstellung eines elektrischen Zuheizers gemäß dem dreizehnten Ausführungsbeispiel,

Fig. 25

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem vierzehnten Ausführungsbeispiel,

Fig. 26

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 25,

Fig. 27

eine ausschnittsweise, vergrößerte Darstellung eines elektrischen Zuheizers gemäß dem fünfzehnten Ausführungsbeispiel,

Fig. 28

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 27 ohne Kontaktblech,

Fig. 29

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem sechzehnten Ausführungsbeispiel,

Fig. 30

eine ausschnittsweise, vergrößerte Darstellung des Zuheizers von Fig. 29,

Fig. 31

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem siebzehnten Ausführungsbeispiel,

Fig. 32

eine Seitenansicht des Zuheizers von Fig. 31,

Fig. 33

eine perspektivische Darstellung eines elektrischen Zuheizers gemäß dem achtzehnten Ausführungsbeispiel,

Fig. 34

eine Variante des siebzehnten Ausführungsbeispiels,

Fig. 35

eine Seitenansicht eines elektrischen Zuheizers gemäß dem neunzehnten Ausführungsbeispiel,

Fig. 36

eine Seitenansicht eines elektrischen Zuheizers gemäß einer Variante des neunzehnten Ausführungsbeispiels,

Fig. 37

eine perspektivische Darstellung des elektrischen Zuheizers von Fig. 36,

Fig. 38

eine perspektivische, ausschnittsweise Darstellung eines Bereichs des Heizelements des Zuheizers von Fig. 36,

Fig. 39

einen Randbereich eines Zuheizers gemäß dem ersten Ausführungsbeispiel,

Fig. 40

eine schematische Darstellung des Randbereichs von Fig. 39 im Falle eines geklemmten Zuheizers,

Fig. 41

eine schematische Darstellung des Randbereichs von Fig. 39 im Falle eines gekleben Zuhelzers, und

Fig. 42

eine schematische Darstellung des Randbereichs von Fig. 39 im Falle eines Zuheizers, bei dem das Kontaktblech mit den Enden der äußeren Stege umspritzt ist.

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

1 is a fragmentary enlarged view of an electric auxiliary heater according to the thirteenth embodiment;

Fig. 25

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

Fig. 26

a fragmentary, enlarged view of the auxiliary heater of Fig. 25 .

Fig. 27

1 is a fragmentary enlarged view of an electric auxiliary heater according to the fifteenth embodiment;

Fig. 28

a fragmentary, enlarged view of the auxiliary heater of Fig. 27 without contact plate,

Fig. 29

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

Fig. 30

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

Fig. 31

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

Fig. 32

a side view of the auxiliary heater of Fig. 31 .

Fig. 33

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

Fig. 34

a variant of the seventeenth embodiment,

Fig. 35

a side view of an electric auxiliary heater according to the nineteenth embodiment,

Fig. 36

a side view of an electric heater according to a variant of the nineteenth embodiment,

Fig. 37

a perspective view of the electric heater of Fig. 36 .

Fig. 38

a perspective, partial view of a portion of the heating element of the auxiliary heater of Fig. 36 .

Fig. 39

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

Fig. 40

a schematic representation of the edge region of Fig. 39 in the case of a clamped auxiliary heater,

Fig. 41

a schematic representation of the edge region of Fig. 39 in the case of a glued Zuhelzers, and

Fig. 42

a schematic representation of the edge region of Fig. 39 in the case of an auxiliary heater, in which the contact plate is molded with the ends of the outer webs.

An electric heater 1 with a depth of 25 mm for a motor vehicle air conditioning (not shown), 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 electrical contacting of 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 webs lower outer webs 4a and central inner webs 4b, which are separated from each other by air channels 5, namely outer air channels 5a between the outer webs 4a and inner air channels 5b between the inner webs 4b and offset with respect to the adjacent web row gap are.

Between the webs 4a and 4b connecting regions 6 are formed, via which a transverse distribution of the current flow between the webs 4 can take place. 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 portions 6 are each closer to the outside of the heating element 2, i. at the corresponding contact plate 3, as arranged at the other connection region 6, i. 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 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 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 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, i. between the connection region and the contact plate 3, derived and also on the connection region, if necessary, a distribution of the current over the entire width of the PTC element is made, 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 are 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 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 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 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 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, 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 are not formed in the depth direction of the heating element 2 over the entire depth, but each only over half of the depth, with adjacent webs 4b are arranged offset, ie a luftanströmseitiger web 4b ', extending from the Air inlet side extends to the center of the heating element 2, in the middle 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 outlet side of the heating element 2. Die Außen Stege 4a are formed continuously in the depth direction and over the width of the heating element at 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 vorliegednen 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. 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 intake 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 rounded portions 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 the 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 or below. In the present case, the connection regions 6 are formed without such structures, but a corresponding configuration can also be made in this region.

Fig. 24 shows a thirteenth embodiment of an auxiliary heater 1, wherein the heating element 2 has a block-like shape with a plurality of slot-like, arranged in parallel, inner air channels 5b, which are separated by webs 4 from each other. In contrast to the preceding exemplary embodiments, the connecting regions 6 are arranged on the outside, that is to say the heating element 2 has no outer webs in the present case. For the electrical contact is on opposite sides of the Heating element 2 each arranged a contact plate 3, which has knob-like spacers 4a ', which are formed by means of forming (embossing) and abut with their ends on the outer surface of the heating element 2. By the spacers 4a 'is formed between the heating element 2 and the contact plate 3, a gap which is divided by the spacers 4a' in individual outer air channels 5a, ie in this case, as in the case of the previously described embodiments in which the function the spacer 4a 'is taken over by the outer webs 4a, the area of the power inlet and -ausleitung is circulated air and thereby cooled.

The configuration of the spacers does not necessarily have to be knob-like. Rather, it is also possible, for example, over the entire depth of continuous waves, bent-out tabs (possibly also with spring function) or soldered ribs or cones, however, a sufficient current flow through the corresponding areas and avoiding excessive current densities in the field of current input or Ausleitung in or out of the heating element, which lead to a Abregeln as a result of excessive heating, must be ensured. Optionally, for better distribution of the current flow, a surface coating may be provided on the side of the heating element adjacent to the contact plate.

The FIGS. 25 and 26 show a fourteenth embodiment. Here, the central structure of the heating element 2 corresponds to the heating element described above. In contrast, on the outer surfaces, which are opposite to the contact plates 3, three rows of seven cylindrical pins of PTC material, which serve as spacers 4a ', molded. Between the pin turn outer air channels 5a are formed, which are traversed by air, so that the Contact areas between contact plate 3 and pin, as well as the pins themselves are well cooled.

According to the fifteenth embodiment incorporated in the FIGS. 27 and 28 is shown, instead of cylindrical pin as a spacer 5a 'pin with externally rounded, star-shaped cross-section formed on the outer surfaces of the heating element 2. Due to the externally rounded, star-shaped cross-section of the pin has an enlarged surface, so that the heat output is improved.

In addition to the in the FIGS. 27 and 28 illustrated shape of the pin are any other embodiments with increased surface possible. Here, for example, thread-like grooves or grooves extending only over part of the pin length, possible. Furthermore, the basic shape does not necessarily have to be a circular cylinder, but, for example, elliptical, streamlined or rectangular cross-sections are possible as a basic shape-possibly even without an enlarged surface.

The spacers 4a 'according to the in the FIGS. 29 and 30 illustrated embodiment are formed by formed on the heating element 2 knobs, which in turn are arranged in three rows with seven spacers 4a '.

Any other arrangement and numbers of spacers are possible instead of three rows of seven spacers each, however, in order to reduce the flow resistance, an alignment of the spacers in the air flow direction is preferred.

In the FIGS. 31 and 32 is shown an electric heater 1 according to the seventeenth embodiment, wherein the Heat transfer region of this embodiment corresponds to that of the fifth embodiment, so that will not be discussed in detail. As in particular from Fig. 31 can be seen, in the contact plates 3 in the depth direction of the auxiliary heater 1 extending slots are formed, which are formed as a result of a double-T-shaped configuration of the slots two extending in the depth direction tongues 3 '. In the slots protrude elongate outer webs formed 4a and are clamped between the tongues 3 ', that is, there is a clamping connection between the contact plates 3 and the heating element 2 is provided. In the present case, every second outer web 4a is formed extended. However, other embodiments are possible, for example. Only every third or only the outermost outer web can be formed extended. In conjunction with a clamping connection, an adhesive may be provided, which additionally secures the connection.

Fig. 33 shows an electric heater according to the eighteenth embodiment. In this case, "unlike" in the previous embodiment, each normally absent, second outer web, so that only elongated outer webs 4a are provided, which protrude through slots in the contact plates 3 and are held therein by means of clamping connections of the tongues. In the area between two outer webs 4a, the heating element 2 is planar, ie the connecting region 6 extends straight in this area. How out Fig. 33 can be seen, two heating elements 2 are provided, for which the contact plates 3 are provided with slots such that alternately a heating element 2 is taken from above and a heating element 2 from below in slots. In principle, a corresponding configuration of the contact sheet is only required in the case of the middle contact sheet, which is contacted from both sides. The outer contact plates may have fewer slots, but the design consistency reduces the number of parts required and thus the manufacturing and storage costs.

Fig. 34 shows a variant of an auxiliary heater 1 according to the seventeenth embodiment, wherein two heating elements 2, as described according to the seventeenth embodiment, are connected to each other by means of a central contact plate 3. For this purpose, the elongated outer webs 4a of the two heating elements 2 are arranged offset, so that in each case an elongated formed outer web 4a of the first heating element 2 next to an elongated outer web 4a of the second heating element 2 is arranged, wherein the elongated outer webs 4a respectively inserted in slots in the contact plate 3 and held by tongues 3 '. Also in this case, the contact areas of the sheets 3 and heating elements 2 are flowed around by air as a result of the provision of the outer air channels 5a and are therefore cooled, so that the PTC material in the region of the outer webs 4a does not abregelt. As a result of the good heat conduction of the contact plates 3, the central contact plate 3 between the two heating elements 2, on both sides of which external air ducts 5a are provided, is sufficiently cooled in spite of its central position.

The Fig. 35 shows a nineteenth embodiment of an auxiliary heater 1, wherein present - according to the variant of the seventeenth embodiment - two heating elements 2 adjacent to a central contact plate 3 are arranged. The outer webs 4a of the heating elements 2 are presently designed such that the outer webs 4a are each arranged offset to the inner webs 4b, wherein an outer web 4b is provided only at every second location. The connecting region 6 between the webs 4 is flat in the regions in which no outer web is provided, ie extend parallel to the contact plates 3. In the other areas, ie in extension of an outer web 4a, the connecting region 6 is pulled out in a V-shape. Further, two adjacent outer lands 4a are V-shaped merges and ends in an extension to the outside, ie the two webs together with extension have a Y-shaped figure. The function of the extension is the same as that of the outer region of the previously described extended outer webs, namely it is inserted into a slot in the contact plate 3 and is held by tongues 3 '.

Due to the merging of two outer webs 4a, two different air duct configurations of the outer air ducts 5a are provided, namely an approximately triangular and an approximately trapezoidal configuration, in the present case only the trapezoidal outer air ducts 5a between the individual contact areas of heating element 2 and contact plate 3.

The function of the tongues 3 'is supported by end-mounted on the contact plates 3 brackets 3 ", which engage behind a formed on the heating element 2, nose-shaped projection and thereby hold the heating element 2.

The representations of the FIGS. 36 to 38 show a variant of the embodiment described above, which differs only in that the outer side clips omitted, but the ends of the elongated outer webs 4a are widened, so that an undercut to the tongues 3 'is provided and thereby the heating element. 2 is held on the contact plate 3.

For double securing both the outer end of the extension can be formed widened as well as brackets may be provided on the outer sides of the contact plates in conjunction with lugs on the heating element.

Any other arrangements of the webs, spacers and connecting portions, deviating from those described above 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 in Fig. 40 shown schematically. For this purpose, heating element and contact plates are arranged in a frame and the force required to clamp 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. 41 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.

An encapsulation of the contact plates 3 with the PTC material is possible, wherein the contact plates 3 preferably have corresponding openings, such as slots and / or holes to safely with the aid of be held by the openings squat material due to a positive connection (see Fig. 42 ).

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

Claims (26)

1. An electrical heater or auxiliary heater, in particular for a heating or air conditioning system of a motor vehicle, with at least one heating element (2) having at least one PTC element, which serves for the heating of a flowing medium, and the PTC element at least one row, consisting of a plurality of webs (4) which are connected to each other via at least one connecting portion (6), and the PTC element for Stromein- or -ausleitung at two opposite edge regions which are perpendicular or substantially perpendicular to the flow direction of the Mediums are arranged, via contact plates (3) is electrically contacted, characterized in that at least one directly adjacent area of the heating element (2) contacting surface of the contact plate (3) and at least one directly adjacent region of the contact plate (3) contacting Surface of the heating element (2) an outer air channel (5a) limited by the Heizel ement (2) and the contact plate (3) is formed, wherein a plurality of Stromein- or -ausleitbereichen is provided, which are separated from each other by said outer air channels (5a). 2. Electric heater or heater according to claim 1, characterized in that the connecting region (6) spaced from the electrically contacting edge regions is formed, and the spaced apart, outer ends of outer, outer webs (4a) of the Stromein- or serve out, wherein the connecting portion (6) forms part of the boundary of the outer air channel (5a). 3. Electric heater or auxiliary heater according to claim 1 or 2, characterized in that the connecting region (6) forms the electrically contacting edge regions, and between the contact plate (3) and the connecting region (6) spacers are provided, which the outer air channels (5a ) separate each other. 4. Electric heater or heater according to claim 3, characterized in that the spacers are formed on the contact plate (3). 5. Electric heater or heater according to claim 3, characterized in that the spacers are formed on the heating element (2) and are electrically conductive. 6. Electric heater or heater according to claim 5, characterized in that the spacers are formed from PTC material. 7. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that the heating element (2) has at least three rows of webs (4), which are separated by connecting regions (6). 8. Electric heater or heater according to claim 7, characterized in that the heating element (2) exactly three rows of Having webs (4), which are separated by two connecting portions (6). 8. 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. 9. 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. 10. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that 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. 11. Electric heater or heater according to one of the preceding claims, characterized in that the air channel width between the webs (4) is 1 to 10 mm. 12. An electric heater or auxiliary heater according to one of the preceding claims, characterized in that the connecting region (6) is formed at least in a sectional plane as over the entire width of the heating element (2) extending surface. 13. 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 adjacent to the contact plates (3) arranged outer sides of the heating element (2) is formed. 14. An electric heater or auxiliary heater according to claim 13, characterized in that the connecting region (6) is disposed within a height range and spaced from the electrical contact, wherein the height range of a minimum height, which of the minimum width of a web (4) or the minimum width of a connecting portion (6) corresponds, up to a maximum height, which corresponds to one third of the total height of the heating element (2), extends. 15. An electric heater or auxiliary heater according to one of the preceding claims, characterized in that at least a part of the webs (4) extends parallel to each other. 16. 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. 17. Electric heater or auxiliary heater according to one of the preceding claims, characterized in that at least a part of the webs (4), in particular the inner webs (4b), extends over only a part of the total depth of the heating element (2). 18. An electric heater or heater according to claim 17, characterized in that the outer webs (4a) are formed continuously in the depth direction. 19. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that the connecting region (6) is zigzag-shaped or wave-shaped, wherein on each mountain or under each valley in each case a web (4) is provided. 20. Electric heater or auxiliary heater according to claim 19, characterized in that the width of the connecting region (6) is 40% to 60%, in particular 50%, of the width of a web (4). 21. An 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. 22. Electric heater or heater according to one of the preceding claims, characterized in that the heating element (2) consists of a polymer, in particular a polyolefin, with electrically conductive filling materials, in particular carbon, in particular in the form of soot particles. 23. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that at least two heating elements (2) are provided, between the heating elements (2) a contact plate (3) is arranged, and on both sides of the contact plate (3) outer air ducts (5a), separated by spacers, are provided. 24. An electric heater or auxiliary heater according to any one of the preceding claims, characterized in that at least one adjacent to an outer air channel (5a) arranged spacer formed extended and inserted into a slot in the contact plate (3). 25. Motor vehicle heating or air conditioning characterized by at least one electric heater or heater (1) according to one of the preceding claims.

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