EP2268103A1 - Electric heating device - Google Patents

Abstract

The electric heating device has an open housing, in which multiple positive temperature coefficient-heating elements (18) are held with radiator elements (14) by clamping opposite to each other. The housing forms multiple separators. A heating rod (24) is included with radiator elements in individual separators and is held opposite to each other by clamping. The heating rod is made of positive temperature coefficient-heating element. An independent claim is also included for a housing for an electric heating device with a housing cover segment.

Description

The present invention relates to an electric heater having an open case in which a plurality of PTC elements and adjoining radiator elements are biased against each other.

Such electric heaters are well known as PTC heaters for motor vehicles and, for example, in the applicant EP 1 564 503 B1 described.

The PTC heating elements have self-regulating properties. Their electrical resistance increases with higher temperature, which brings with the use of PTC heating elements for heating air in a motor vehicle with the advantage that the electric heater can not overheat. On the other hand, due to the self-regulating properties, the heat generated by the PTC heating elements must be dissipated effectively. For this purpose, on the one hand to ensure that the heat generated by a PTC element is first derived via heat conduction in a plane regularly transverse to the radiator elements. A PTC element, i. a ceramic stone is regularly arranged between two contact plates. This arrangement forms a PTC heating element. The contact plates can in turn already be part of the radiator element. The radiator elements are formed from metallic material with good heat conduction and conduct the heat initially introduced into the radiator elements via heat conduction to the air flowing in the radiator elements.

In the prior art fundamentally different concepts are known, as the above-described good electrical and thermal contact between the heating element and the adjoining radiator elements can be effected.

That's how it describes EP 1 621 378 a cohesive connection by means of adhesive or solder between the PTC element and the adjacent contact plate and the corrugated rib called radiator elements.

In another embodiment according to the aforementioned generic art or the EP 1 731 340 B1 a plurality of PTC heating elements are clamped with adjoining radiator elements under the bias of a spring in the housing. The spring retains the heating block formed by the PTC heating elements and the adjoining radiator elements within the housing. A corresponding embodiment also discloses the already mentioned above EP 1 564 503 B1 ,

When biasing a heating block in a housing, however, are to be compensated by the or the spring elements significant amounts. Accordingly, the spring must be able to apply the necessary elastic bias over a longer travel. This regularly leads to the requirement of a spring from a spring band, which occupies a certain amount of space in the heating block contained in order to bring about the necessary spring force over the required travel to compensate for tolerances can.

Also, it often poses a problem to receive the heater block within the housing under spring bias in the housing. This is particularly problematic when initially the elements of the heating block under spring preload inserted into the still open housing and only then the housing is closed.

From the date of the applicant EP 1 564 503 Although a heating block is known, which is held under the bias of a spring in the housing, which is tensioned by a displacer, which is introduced when closing the housing in this. In this respect, the layer structure known from this prior art can first be mounted without pretensioning in the housing and brought under pretension when the housing is closed. But even this electric heater has disadvantages, since this can be adapted to any dimensions for the electric heater with considerable effort.

Sometimes it is necessary to arrange the electric heater in a space within the housing of a climate module in a vehicle relatively space-building, to cover the entire area penetrated by the air. The area can sometimes be greater than that required for the heating power with effective use of the heating block forming elements. In this case, the heating block must be designed to be relatively space-consuming, resulting in not inconsiderable additional costs. Although the number of PTC elements within the heating block can be adapted to the desired heating power. Nevertheless, the entire air passage area within the housing must be filled with PTC heating elements and adjoining radiator elements.

Remedy that creates from the EP 1 621 378 Known solution in which individual each formed by a PTC heating element and adjoining radiator elements heating elements leave between them a space that is blinded by a plastic grid. The plastic grid is intended to prevent a bypass flow and form a flow resistance within the housing, so that the air to be heated in any case also illuminates the radiator elements of the heating elements and is thus heated. The from the EP 1 621 378 known device wants to allow a good thermal homogenization. If in a housing predetermined dimension a larger heating power is required, instead of the plastic mesh each a further heating element is installed in the housing.

In the from the EP 1 731 340 B1 Known solution principle plastic Platzhalterelemente be accommodated in the overall held under spring tension in the housing heating block to form a large-scale, while inexpensive to produce electric heater. This solution proposal can be like the proposed solution after the EP 1 621 378 B1 from the idea that the placeholders can be replaced by heat-generating PTC heating elements with adjoining radiator elements at the desired higher heat output within the housing.

The present invention has for its object to provide an improved electric heater. In this case, the present invention seeks to provide a simple and inexpensive to manufacture solution as a development of a generic electric heater, in which the PTC heating elements bear with the adjoining radiator elements under bias against each other.

To solve this problem, the generic electrical heating device is further developed by the present invention, wherein the housing forms a plurality of compartments, in individual compartments each heating rods formed from a PTC heating element with both sides adjacent thereto received radiator elements and their elements held under bias against each other are. The PTC heating element comprises, in a manner known per se, at least one PTC element, which is preferably accommodated, preferably clamped, between two electrically conductive sheet metal strips. Respectively on the outside of the PTC Heizelemtes the radiator elements abut it. The radiator elements are exposed in the air flow of the air to be heated, which flows through openings of the open housing. A compartment of the housing is in each case dimensioned such that only one heating element, ie a unit of PTC heating elements with adjoining radiator elements can be included in the Gefach. The heating elements are each held in separate compartments. The heating element forming elements are each held under bias against each other fitting in the Gefach.

The solution according to the invention has the advantage that a spring biasing the elements in a compartment must compensate only a small tolerance. This offers the possibility to assign a relatively simple, inexpensive to manufacture spring assembly each Gefach to put the elements held in the Gefach elements under bias against each other. Such a spring arrangement may for example be formed exclusively of plastic parts. Corresponding plastic parts for bracing the PTC heating elements and the adjoining radiator elements in an electric heater as a heater for a motor vehicle are not known in practice until today. With the present invention, the possibility is opened up for the first time to use corresponding spring elements made of plastic for clamping heat-generating and heat-emitting layers within the housing. In this case, the spring elements formed of plastic are usually distributed in the interior of the housing and are each associated with the individual compartments. A spring element can only clamp the elements of a heating element in a single Gefach against each other. But it can also be provided spring elements made of plastic, which hold the elements of the heating elements in two adjacent compartments against each other under bias.

For each Gefach a preferably the elements of the heating element under bias voltage setting spring element is provided. In any case, there is at least one spring element at a distance from an edge of the housing within the same.

According to a preferred embodiment of the present invention, the heating stages of the electric heating device are in each case for themselves recorded heating elements in the individual compartments. In other words, each individual heating element accommodated in a separate compartment forms a respective heating stage. According to a further preferred embodiment of the present invention, all PTC heating elements and the adjacent thereto radiator elements of the electric heater are each combined to form heating elements and provided in separate compartments. In this preferred embodiment of the present invention, the electric heater is formed solely of heating rods, which are each taken up in a separate Gefach.

According to a further preferred embodiment of the present invention, which allows the realization of an electric heater with relatively large dimensions at relatively low production costs, adjacent compartments are closed with housing cover sections which are fixed to a housing lower part and release between them formed by the housing base spacer, which connecting neighboring compartments. Thereafter, only the lower housing part forms the spacer element. This can set any distance between adjacent compartments. The spacing element itself is preferably not connected to a housing cover section. Rather, the spacer element is completely or partially exposed between the housing cover sections. In a sectional view through the housing thus result in two-part sealed sections where compartments are closed with housing cover sections, and one-piece sections where a spacer is provided between adjacent compartments. Housing cover sections in this preferred embodiment may each be separately formed housing cover segments, which are assigned only to a Gefach to close this. However, housing cover sections may also be provided on a uniformly shaped housing cover which forms bridges in the area of the spacer elements only via thin webs, preferably webs provided at the edge, which connect adjacent, preferably all housing cover sections with one another. In any case, material can be saved for the housing cover in the region of the spacer elements, whereby the cost of creating the housing and thus the electric heater can be reduced. The spacers may be in the transverse direction, i. be made arbitrarily wide across the longitudinal extent of the individual heating elements to create the largest possible electric heater at low production costs.

To improve the strength, it is proposed according to a preferred development of the present invention to form the spacer element offset in relation to a bottom of the housing lower part in the thickness direction of the electric heater inwardly. The spacers are preferably formed as relatively thin webs that connect adjacent compartments together. Thin webs are in particular realized in an embodiment in which the webs occupy only a thickness of 3% to 15% of the total thickness of the housing. Preferably, the webs are located approximately at mid-height of the housing.

To even out the air resistance over the air passage surface of the open housing is proposed according to a further preferred embodiment of the present invention, to provide at the spacer air passage openings. The air passage openings have a flow resistance which corresponds approximately to the flow resistance of the heating elements. In any case, the flow path allowed through the air passage openings should not oppose the air flow with significantly lower resistance than heating rods provided adjacent thereto. Otherwise, it would be feared that the majority of the air will flow through the spacers without being effectively heated.

With the present invention, a housing for an electric heater of the aforementioned type is further proposed, which forms a housing base with compartments for receiving at least one heating element comprising a PTC heating element and on both sides fitting radiator elements and a spacer element, which spaced the compartments from each other and each other combines. This housing can be inexpensively used for the production of an electric heater of the type mentioned, which occupies a relatively large space. The housing and thus the electric heater can be made material-friendly and therefore inexpensive.

According to a preferred embodiment, the housing has adjacent compartments covering housing cover sections, which are connectable to the lower housing part and release a spacer between them, which is formed by the lower housing part. The individual housing cover sections may be formed by separate housing cover segments. However, housing cover sections may also be part of a unitary housing cover which is connected, for example by latching connection with the housing lower part. A one-piece design of the housing cover is to be preferred in view of easy installation. However, it should be noted that with regard to the desired spring tension of the individual elements of the Gefaches these are preferably produced by elements that generate only the spring tension when introduced into the plane of the radiator elements or PTC heating elements, ie imprint a spring preload. Although such an embodiment is preferable to install in each Gefach the radiator elements and the PTC heating element initially without distortion and to put under closing the housing under tension. However, the design goes hand in hand with an increased resistance when placing the housing cover is necessary to connect not only the housing cover with its locking lugs on the housing base, but at the same time to put the or the spring elements under tension. In view of this, it may be necessary to provide a plurality of housing cover segments, which can be joined with medium contact force with the housing lower part. The spacer element is preferably offset from the bottom of the housing lower part in the thickness direction of the housing inwardly provided. Accordingly, the spacer element is not in the plane in which the bottom of the housing base is located. Preferably, the spacer element is located in the height direction approximately in the middle of the housing, and particularly preferably in the form of a two compartments interconnecting web. From the reasons already mentioned above with reference to the electric heater, the spacer element preferably has air passage openings.

As previously stated, the electric heater preferably has a spring assembly formed entirely of plastic. For this purpose, it is proposed according to a preferred embodiment of the invention to form the housing with an upper housing part and a lower housing part, the lower housing part, wherein the lower housing part comprises at least one projecting from its bottom support member and the upper housing part comprises a projecting from its lid surface counter-element to the support element. The support member and the counter-element are designed such that these two elements cooperate when closing the housing with a spring element made of plastic, which is clamped between the support member and the counter-element to generate elastic deformation components and elastically stores these deformation components. This spring arrangement may be associated with a single compartment with a single heating element. However, the spring arrangement described above can also hold the elements of a heating block comprising a plurality of PTC heating elements and adjoining radiator elements under prestress in the housing.

In a preferred development, the electric heating device has an open housing, in which at least one PTC heating element and radiator element are held under prestress, the housing having an upper housing part and a lower housing part which leave openings for the passage of a medium radiating the radiator elements. The lower housing part has at least one support element projecting from its bottom. The upper housing part has a counter-element protruding from its lid surface to the support element. The support member and the counter element act together when closing the housing with a spring element made of plastic, which is clamped between the support member and the counter element and thus stores generated elastic deformation components.

This embodiment offers the possibility of receiving a receptacle, in particular a receptacle for a single heating element comprising a PTC heating element, each with a laterally adjacent thereto radiator element in a Gefach a housing for itself and under bias, said bias by a spring element made of plastic is effected. Although a spring element made of plastic as for the stress of heat generating and heat-emitting layers of an electric heater of the generic type was considered unsuitable, investigations by the Applicant have shown that such spring elements in particular with good tolerance vote between a receptacle for the heat-generating and the heat-emitting elements within the housing and the dimensions of these heat-generating and heat-emitting elements, the necessary tension can also be effected by a plastic spring element.

The spring tension is preferably effected only when closing the housing. Here, by interaction of the support element and the counter element, a deformation of the spring element, in which elastic deformation parts are generated in this. Due to the elasticity of the spring element these deformation components are stored, so that the spring element is suitable to track any self-amounts and thermally induced changes in dimensions. The individual layers of radiator element and PTC heating element are therefore reliable and permanently under spring preload against each other.

According to a preferred embodiment of the present invention, the spring element is formed by a longitudinally extending plastic tendon which is deformed by provided in its longitudinal direction in an alternating manner supporting and counter-elements for storing elastic deformation components. In an alternating manner, the support and counter elements are preferably provided so that adjacent to a support element in the longitudinal direction of the plastic chord initially follows a counter element. However, the support element and the counter element can partially overlap in the longitudinal direction. As a longitudinal direction, the extension direction of the individual layers of a heating stack or a heating block is considered, ie the longitudinal extension of the example PTC heating elements with their elongated metal bands. Preferably, in each case three of the said elements are combined to form a group in order to bend the spring element at a predetermined point through alternating support points. The arrangement is carried out with the aim of producing the spring tension primarily in that length section in which a PTC element to be clamped by the spring tension is located inside the housing. With regard to the simplest possible design, it is preferable to provide a single support member centrally between two adjacent counter-elements, so that the alternating bending of the plastic chord takes place by three support points, of which the middle are formed by the support member and the two outer by the counter-elements ,

According to a preferred embodiment, the plastic tendon is formed by a plastic tape inserted into the housing. The plastic band can have different cross-sectional shapes. The plastic band can be an elongated flat band. Alternatively, the design of the plastic strip in the form of a cord with circular or any other arbitrary cross-section is conceivable. The plastic band can extend over the entire length of the housing. As well, the band can be divided into segments and extend only over a partial length of the housing.

It has surprisingly been found that the formation of a plastic strip by a flexible plastic element causes a sufficient elastic tension. As a flexible plastic element is for example a thermoplastic elastomer or silicone in question. The plastic band should have a high elasticity. With regard to heat resistance, rubbers are also conceivable as soft-elastic plastics for forming the plastic strip. However, the plastic band does not have to be formed exclusively from corresponding soft elastic plastics. It may also contain a core, for example of a fiber. The addition of fillers is conceivable.

According to an alternative embodiment, the plastic tendon is integrally molded onto the housing lower part and / or the upper housing part. It has been shown that a corresponding plastic tendon can already be created with the plastics usually used to form plastic housings. Accordingly, the housing can be made entirely of a uniform material by means of injection molding. It is also conceivable, however, the molding of a plastic chord by molding with a other component. Thus, a plastic tendon made of a plastic with high elasticity can be inserted as an insert in an injection mold, which is used to form the lower housing part and / or the upper housing part. Thereafter, a plastic chord molded integrally on the housing part does not necessarily have to be identical to the housing part.

Good clamping of the PTC heating element with adjoining radiator elements is created, for example, by providing the plastic tendon approximately at the middle height of the receiving space in the closed housing. The receiving space is thereby between the opposite inner surfaces of the lower housing part and the upper housing part, i. limited between the housing bottom and the top surface of the housing top. The cover surface is the inner surface of the upper housing part. The plastic tendon is not only preferably provided approximately at mid-height of the housing space, but preferably limited to this area substantially. The plastic tendon therefore preferably extends only over a central region of the height of the housing space, preferably at a height corresponding to 7 to 15% of the height of the receiving space. In this way, caused by the plastic tendon spring preload can be effectively used to clamp the PTC heating element with adjoining radiator elements.

According to a preferred development, the upper housing part or the lower housing part has an abutment element formed integrally thereon. By this contact element caused by the spring element bias in the layered structure consisting of at least one PTC element and at least one radiator element is introduced. The contact element accordingly conveys the spring force to the layered structure. The contact element is pivotally mounted relative to that housing part on which it is integrally formed. The pivot axis extends parallel to the longitudinal direction of the housing, ie the longitudinal extent of the PTC heating element. Preferably, the pivot axis is close to or in the plane of the bottom of the housing base or the cover surface of the housing upper part. In any case, the abutment elements preferably protrude freely from the corresponding surface sections of the upper housing part or lower housing part, so that their pivotability about the said pivot axis is not obstructed by connection to side walls of the upper housing part or lower housing part.

According to a preferred embodiment of the present invention, the contact element on the side facing away from the spring element has an inclined sliding surface. This sliding surface simplifies the installation of PTC heating element and radiator element in the housing. The installation of a particular heating rod causes a certain elongation of the contact elements in the direction of the spring element. The sliding surface ends, for example, approximately at mid-height of the housing space for transmitting the spring force in a plant projection. This investment projection is usually on one of the radiator elements. Due to the aforementioned embodiment, the contact element is biased when introducing the PTC heating element and the adjoining radiator elements in the housing in limits in the direction of the support element. The particular located between the support element and the contact elements spring element urges the contact element, for example in the central region against the adjacent radiator element, whereby this is biased against the PTC heating element and this in turn against the other radiator element under bias.

To facilitate the introduction of the plastic tape in the housing, it is proposed according to a preferred embodiment of the present invention to provide the sliding surface facing away from the rear side of the contact elements extending substantially at right angles to the ground extending orientation and pointing to the contact elements inclined surface of the support element in the direction of the contact elements inclined to train. By this inclined configuration, a funnel-shaped tapered receptacle for the plastic strip is formed together with the back of the contact elements. On the one hand, this simplifies the insertion of the plastic strip. On the other hand, the plastic tape approaches when inserted into the housing by sliding on the inclined surface of the back of the or the contact elements and is thereby inevitably brought into the correct position to transmit the spring force preferably approximately centrally against the radiator element.

This end position of the plastic tape is safely taken in a preferred embodiment of the present invention, in which the inclined surface merges into a support for the plastic strip, said support extending substantially parallel to the bottom. The support serves as a contact surface for the plastic tape and positioned selbiges in the height direction in the housing space. Incidentally, this support prevents a plastic spring elastically deforming by compression in the direction of insertion of the counter element shifted in the direction of the lower housing part and thus escapes the applied tension. The support may be enclosed between adjacent counter-elements. However, embodiments are also conceivable in which the support and the counter element partially or completely overlap in the longitudinal direction of the housing.

According to a further preferred embodiment of the present invention, an elastic deformation components on the PTC element transmitting contact surface is provided. This contact surface is formed regularly by the contact element. The contact surface is movable to transmit the elastic deformation components in the direction of action of the tension. The abutment surface is preferably effective only over a small height of the entire receiving space, i. is only on a small height section, for example, the radiator element. The contact surface can be provided in the height direction at any position within the receiving space. The contact surface should, however, be provided at the same height as the associated PTC element. The contact surface does not necessarily have to transfer the deformation components directly to the PTC element. Rather, an indirect transfer of the deformation components to the PTC element via other layers of the layered structure, for example the radiator element or sheet metal strips provided between the contact surface and the PTC element is conceivable. With the contact surface and the substantially level arrangement of the associated PTC element is to ensure that the spring force generated by the spring is best transmitted to the PTC element.

It has, however, been found preferable to provide the contact surface and / or the PTC element off-center in the height direction of the housing and close to the air inlet side of the electric heating device. The air inlet side is the side through which the air to be heated enters the open housing. Preferably, the PTC element is located directly below a cover of the housing upper part or the housing lower part which forms the opening provided for this purpose. The development can also be realized according to the invention and in a conventional electric heater in which the layer structure or the heating element is held under bias of a metallic spring. It is also conceivable eccentric arrangement of the PTC element in a position frame which is completely or partially covered by the opposing metal strips. Continuing education can be guided by the idea in that the PTC element accommodated in the housing has a lower height than the radiator element associated with the PTC element, the latter determining the height of the receiving space within the housing.

The corresponding arrangement of the PTC element off-center is achieved in particular by the fact that at least one PTC element associated retaining rib is formed on the housing lower part or the housing top, which extends in any case in sections in the longitudinal direction of the housing and through which the PTC element near the air inlet surface is provided. However, the said retaining rib preferably has not only the function of arranging the PTC element in the height direction off-center within the receiving space. Rather, the retaining rib also serves to stiffen the housing part and penetrates this preferably continuously in the longitudinal direction.

In a preferred embodiment, the spring element preferably has, together with the counter element, a U-shaped configuration open to the bottom of the housing lower part. In this embodiment, preferably forms a substantially parallel to the counter element extending leg of the spring element a contact surface for abutment against the adjacent radiator element, which bears against it under bias and exerts a spring force on the heating element. The spring element preferably has, in addition to the two protruding in the direction of the bottom of the lower housing part legs a connecting web, which is provided with the housing closed between the middle height of the housing space and the lid surface. This web serves as a spring bar and preferably has a curved in the direction of the housing cover design, so that the web to produce a spring preload can be deformed upwardly bulging.

According to a preferred embodiment of the invention, a substantially parallel to the counter element extending spring leg is firmly connected to the housing cover. The parallel extension between counter-element and spring leg is obtained in particular with an unloaded spring element, i. before assembling the housing. The spring leg preferably extends in the above-mentioned embodiment approximately at right angles to the housing cover.

Preferably, in an integrally formed on the housing cover spring legs, the counter-element forms the abutment element described above, which in one piece and is pivotally connected to the housing part and which preferably forms a contact surface for transmitting the elastic deformation components to the PTC element. In this case, it is assumed that the counter element deforms slightly when the housing is closed and the contact surface is applied, for example to the radiator element. However, the predominant deformation and its elastic storage is absorbed and stored by the spring leg and / or the spring leg connected to the counter element web.

According to a further preferred embodiment of the present invention, the support element forms a ramp-shaped biasing surface against which the spring element slides when closing the housing to produce elastic deformation components.

Fig. 1

eine perspektivische Draufsicht auf ein erstes Ausführungsbeispiel einer elektri- schen Heizvorrichtung;

Fig. 1 a

eine Ansicht gemäß Figur 1 für ein gegenüber dem Ausführungsbeispiel nach Figur 1 abgewandeltes Ausführungsbeispiel einer elektrischen Heizvorrichtung;

Fig. 2

eine Schnittansicht entlang der Linie II-II gemäß der Darstellung in Figur 1;

Fig. 3

eine Schnittansicht entlang der Linie III-III gemäß Figur 2;

Fig. 4

eine Seitenansicht auf eine Federeinrichtung eines zu den Figuren 2 und 3 alter- nativen Ausführungsbeispiels;

Fig. 5

Teile der in Figur 4 dargestellte Federeinrichtung in perspektivischer Darstellung;

Fig. 6

die in Figuren 4 und 5 verdeutlichte Federeinrichtung bei geschlossenem Gehäu- se;

Fig. 7

den gehäuseoberseitigen Teil eines weiteren Ausführungsbeispiels einer Feder- einrichtung;

Fig. 8

die in Figur 7 verdeutlichte Federeinrichtung bei geschlossenem Gehäuse;

Fig. 9

eine perspektivische Draufsicht auf einen Teil eines Gehäuseunterteils eines wei- teres Ausführungsbeispiels der vorliegenden Erfindung und

Fig. 10

eine Schnittansicht entlang der Linie X-X gemäß der Darstellung in Figur 9

Further details and advantages of the present invention will become apparent from the following description taken in conjunction with the drawings. In this drawing show:

Fig. 1

a top perspective view of a first embodiment of an electric heater;

Fig. 1 a

a view according to FIG. 1 for a comparison with the embodiment according to FIG. 1 modified embodiment of an electric heater;

Fig. 2

a sectional view taken along the line II-II as shown in FIG FIG. 1 ;

Fig. 3

a sectional view taken along the line III-III according to FIG. 2 ;

Fig. 4

a side view of a spring means one of the FIGS. 2 and 3 alternative embodiment;

Fig. 5

Parts of in FIG. 4 illustrated spring device in perspective view;

Fig. 6

in the FIGS. 4 and 5 clarified spring device with closed housing;

Fig. 7

the housing upper side part of another embodiment of a spring device;

Fig. 8

in the FIG. 7 clarified spring device with the housing closed;

Fig. 9

a perspective top view of a part of a housing lower part of a further embodiment of the present invention and

Fig. 10

a sectional view taken along line XX as shown in FIG FIG. 9

The FIG. 1 shows a top perspective view of a marked with reference numeral 2 housing comprising a housing lower part 4 and a housing upper part 6, which are interconnected. The housing 2 has two parallel extending covers, of which only the cover 8 formed by the upper housing part 6 can be seen. Within the cover 8 a plurality of openings 10 are recessed, which allow passage of air through the housing 2.

Each of the openings 10 is centrally penetrated by a longitudinal web 12 which extends parallel to below the opening located radiator elements 14 and a heat generating PTC heating element 16 covers, which in the sectional view according to FIG. 2 can be seen and comprises a plurality of longitudinally of the longitudinal web 12 successively arranged PTC elements 18 and on both sides fitting thereto sheet-metal strips 20. The opposite metal strips 20 to a PTC heating element 16 are energized with different polarity. Selected metal strips can be extended in a conventional manner laterally over the housing 2 to form contact tongues (see. EP 1 564 503 ).

The PTC elements 16 with double-sided adjoining radiator elements 14 each form a heating rod 24. The lower housing part 4 forms a Gefach 26 for each heating element 24.

As the sectional view according to FIG. 2 can be seen, a heating element 24 is arranged in each Gefach 26 and held under bias of a spring described in more detail below, so that the individual layers of the heating element 24, ie the radiator elements 14, the PTC elements 18 and the sheet metal strips 20 provided therebetween under bias abut against each other, so that the heat generated by the PTC element 18 is transmitted with good heat conduction to the radiator element 14 and a safe current input can be made at least from the metal strips 20 to the PTC elements 18. In the in the FIGS. 1 to 3 shown embodiment, all metal strips 20 are led out to the formation of plug contacts the front side of the compartments 26.

Between the compartments 26 4 spacers 30 are formed by the lower housing part. These spacers 30 bridge over a web 31 a distance between the compartments 26 and are relative to the outer surface of the housing 2 formed by the cover 2 inwardly offset (see. FIG. 2 ). In the area of the spacer elements 30, the upper housing part 6 provided in the manner of a housing cover is broken through. At the in FIG. 1 In the embodiment shown, the housing upper part 6 has only peripherally provided, connected housing cover sections 32, each covering a Gefach 26, connecting transverse webs 34. Over the vast length of the housing 2, ie the extension in the direction parallel to the radiator elements 6 and the metal strips 20th the spacer elements 30 are released by the housing cover portions 32, so that the housing 2 is formed between the individual compartments 26 is substantially single-layered, that is, only the spacer elements 30 includes. The transverse webs 34 are formed narrow relative to the length of the housing 2 and preferably leave more than 90% of the total length of the housing 2 between the individual compartments 26 free.

The webs 31 of the spacer elements 30 have a plurality of longitudinally of the housing 2 successively arranged air passage openings 36 whose flow resistance of the housing 2 passing air flow is adjusted approximately to the flow resistance of the individual radiator elements 14, so that on the air outlet side of the housing 2 by Mixing of the partial flows through the openings 10 on the one hand and on the other hand by the air passage openings 36 on the other hand in the temperature uniform total flow of exiting air results.

The FIG. 1 a shows an alternative embodiment which is essentially the same as described above with reference to FIG FIG. 1 corresponds described. The same components are identified by the same reference numerals. The main difference of in FIG. 1a shown embodiment with respect to in FIG. 1 shown is that instead of a single housing cover 6 with a plurality of unit cover connected to a housing cover sections 32, this in the embodiment in FIG. 1a are provided as separate housing cover segments 38. The housing cover segments 38 extend in the present case over the entire length of the housing 2 and are fitted in recesses 40, which are recessed at formed by the lower housing part 4 cross bars 42. The respective spacer elements 30 extend in the longitudinal direction of the housing 2 up to the cross member 42. With these housing cover segments 38 results in a multi-part housing upper part. 6

The FIGS. 2 and 3 illustrate a spring means 44, which is formed in the present case only the outer heating element 24 associated. More similar or identically designed spring means may be provided adjacent to further heating elements 24 and / or between two heating elements such that the spring biasing means 44 caused by the elastic biasing force, the layers of adjacent heating elements 24 against each other under bias.

The spring device 44 has integrally formed on the lower housing part 4 supporting elements 46 which are chamfered end with an inclined surface 48. In the longitudinal direction of the housing 2, a plurality of support members 46 is formed by the lower housing part 4. In larger, equally regular intervals, the lower housing part 4 also forms fixing elements 50 whose active surfaces are parallel to the active surfaces of the support elements 46, i. extending at right angles to a bottom 52 of the housing base. The fixing elements 50 are arranged offset relative to the support elements 46. The fixing elements 50 are located approximately in the middle between adjacent support elements 46. Between the support elements 46 and the fixing elements 50, a spring band 54 forming a plastic chord in the sense of the present invention is introduced into the lower housing part 4, which extends substantially over the entire length of the housing 2 , In this case, the spring band 54 is slightly biased between the fixing member 50 and adjacent support members 46 and thus held in the lower housing part 4.

Distancing from the bottom 52, spacer ribs 56 are formed on the housing lower part 4, which space the PTC elements 18 of a PTC heating element 16 in the longitudinal direction of the housing 2 from one another. The spacer ribs 56 extend in the present case over the entire height of the lower housing part 6 and thus also form a contact surface for the upper housing part 4. The fixing elements 50 are arranged in the longitudinal direction of the housing 2 approximately at the height of the spacer ribs 56. In any case, at the height of the PTC elements 18 there are no fixing elements 50. The in FIG. 2 outer radiator element 14 abuts against a contact element 58, which is slightly convex formed on its inner surface facing the radiator element 14 to form a linear contact surface 59, wherein the region of greatest thickness is approximately at the average height of a receiving space 60 formed by the housing 2 the PTC elements 18 extends.

Although the contact elements 58 protrude from the bottom 52 of the lower housing part 4. However, they are not connected end to the housing lower part 4, but cut free via a slot 62, for example, with respect to the cross member 42 or a bearing element 64 which protrudes from the housing bottom at right angles and forms an abutment for the fixing element 50. Due to this configuration, the abutment elements 58 can be pivoted about their feet about an axis which extends parallel to the longitudinal direction of the housing 2.

The PTC elements 8 are deposited on a retaining rib 66, which likewise protrudes from the bottom 52 of the lower housing part 4 and is provided between the transverse member 42 and the adjacent spacer rib 56 or between adjacent spacer ribs 56. With this retaining rib 66, the PTC elements 18 are also accommodated in the housing 2 at a predetermined distance from the bottom 52 within the receiving space 60.

The substantially lid-shaped housing upper part 8 has at its the receiving space 60 facing housing cover surface 67 a plurality of approximately at right angles from the housing cover portion 32 projecting, in the cross-sectional view FIG. 2 This positive displacement 68 are integrally formed on the upper housing part 4 and - relative to the longitudinal direction of the housing 2 - between adjacent support members 46 are provided on both sides spherically shaped, which forms the counter element to the support elements 46.

As the plan view of the open housing lower part 4 according to FIG. 3 can be seen, a plurality of spring means 44 are provided in the longitudinal direction of the housing 2, which are each separated by fixing elements 50 with associated bearing elements 64. Each of the spring devices 44 shown has over the longitudinal extension of the contact element 58 extending and limited thereto displacement 58, which form a counter element to the contact element and associated, alternately provided for this purpose support members 46. The spring band 54 usually runs in one piece over the entire length of the housing 2 ,

To clamp the individual held in a Gefach 26 layers of a heating element 24, the spring band 54 between adjacent support members 46 and the displacement member 68 provided therebetween elastically bent when closing the housing 2 by applying the upper housing part 6 on the lower housing part 4. The generated here Spring preload is forwarded via the contact element 58 to the elements of the heating element 24. Due to the spherical configuration of the displacement element 60 and the abutment element 58, the spring force is focused on the central area of the receiving space (in the vertical direction), ie on the area in which the PTC heating elements 16 are located. Thus, a sufficient electrical contact between the metal strips 20 and the PTC elements 18 of a heating element 24 is effected as well as a sufficient thermal contact between the PTC elements 18 via the metal strips 20 to the radiator elements 14th

The spring band 54 may be a plastic band. Alternatively, the introduction of a spring steel strip is possible. It has been shown, however, that with a spring device 44 which merely has to bias the elements of a heating element 24 in a single compartment 26, which is adapted precisely to the dimensions of the heating element 24, the spring force exerted by a plastic spring element is sufficient. to achieve a good electrical and thermal contact between the PTC elements 18 and the other elements of the heating element 26.

The FIGS. 4 to 6 illustrate an alternative embodiment of a spring means, which is designated for this embodiment by reference numeral 70.

Similar to the support element 56 of the previously discussed embodiment, the spring device 70 has a support element 72 which projects from the bottom 52 of the housing lower part 4 and cooperates with a displacing element 74 projecting from the housing cover section 32 as a counter element around a spring element formed by a silicone cord 76 between alternating support points elastic bias.

For this purpose, the support element 72 has an inclined surface 78, through which a funnel-shaped taper for receiving the silicone cord 76 results, which is open at the top and extends between the support element 72 and contact elements 80 at right angles to the bottom 52. The abutment elements 80 are formed in cross-section as the contact elements 58 and have in addition to the right angles to the bottom 52 extending rear side in the central region a spherical configuration through which a tapered sliding surface 84 and approximately at mid-height of the receiving space 60, a contact projection 86 is formed which cooperates with a neighboring radiator element 14. In the longitudinal direction of the silicone cord 76, a support element 72 is provided between adjacent and mutually associated contact elements 80. The integrally formed on the housing cover portion 32 displacement elements 74 are in the longitudinal direction at the level of the abutment members 80. A subsequent to the sliding surface 84 and extending substantially parallel to the bottom 52 support 88 which is formed by the support member 72 is so in the height direction spaced relative to the bottom 52, that resting on the support 88 silicone cord 76 is located approximately at the height of the abutment projection 86 of the contact element 80.

Also in the FIGS. 4 to 6 shown embodiment of a spring device 70 braces only one heating element 24, has been dispensed with the representation, but which may correspond to the heating element 24 according to the previously discussed embodiment. The arrangement of the PTC element 18 is such that it is located at mid-height of the receiving space 60.

For assembly, the heating element 24 is first introduced into the Gefach. Furthermore, the silicone cord 76 is placed on the support 88, so that the longitudinally extending silicone cord 76 between the rear sides 82 of the abutment elements and the sliding surface 74 of the support member 72 is located.

By closing the housing cover section 32, the displacement elements 74 act on the rear side 82 of the abutment elements 80 against the silicone cord 76. This is thereby elastically deformed between the alternating support points in the height direction of the receiving space 60. The width of the support member 72 may vary depending on the elasticity of the silicone cord. The abutment elements 80 of the support element 72 may also overlap in the longitudinal direction or even be formed continuously in the region of the spring device 44.

The FIGS. 6 and 7 show an alternative embodiment with a plastic spring means, which is designated by reference numeral 90 and characterized by two downwardly U-shaped legs, of which a reference element 92 marked counter element is provided with an inclined surface 74 which can slide on a radiator element 14 and transferred to a Anlagevorsprung 96. The limb of the exemplary embodiment facing away from the radiator element 14 should be designated as a spring element 98, as it is integrally molded onto the housing cover section 32 by injection molding molded leg stores the majority of the elastic deformation component. The two legs 92, 98 are connected to one another via a web 100. This in FIG. 7 shown upper housing part 4 is manufactured as a one-piece component by means of plastic injection molding. Similar to the investment elements 80 of the in the FIGS. 4 to 6 On the side of the housing cover section 32 facing the radiator element 14, ie at the foot of the counter element 92, there is a longitudinal slot 102. On the rear side of the counterelement 92 facing away from the longitudinal slot 102, a further longitudinal slot 104 is recessed which leads to the web 100.

The longitudinal sectional view according to FIG. 8 shows on the side of the lower housing part 4, a spring element 98 associated with the supporting element 106, which forms a sliding surface 108. Over the longitudinal extension of the housing 2, a plurality of spring devices 90 and associated support elements 106 are provided on the side of the upper housing part 4. Again, the corresponding spring devices are preferably in the longitudinal direction at the height of the PTC elements 18th

During assembly, first the elements forming the heating element 24 are inserted into the lower housing part 4. The recorded in the Gefach 24 heating rod 24 is set by closing the housing 2 by applying the upper housing part 6 under tension. Initially, the spring element 98 slides past the sliding surface 108. It is separated from the sliding surface 108 in the region of its foot, i. bent around a bending axis extending in the longitudinal direction of the housing 2. This bend is transmitted via the web 100, which is also resiliently biased. A certain elastic bias also results in the counter-element 92, which is urged against the radiator element 14 as the insertion movement progresses due to the deformation of the spring element 98. In response to this contact force results in a certain elastic deformation of the counter element 92nd

By per se known locking lugs, the upper housing part 6 is finally connected to the associated lower housing part 4.

The in the FIGS. 4 to 8 shown examples of spring means 70, 90 are preferably associated with each individual Gefach 26 and thus a single heating rod 24 to put the components contained therein under bias. To secure the force caused by the spring means 70, 90 spring force are in the region of the respective Spring device locking connections provided by which the lower housing part is connected to the upper housing part, so that the upper housing part 6 does not lift off from the lower housing part 4. As a result, the elastic tension of the spring device 70, 90 is secured. There are then latching connections not only in the edge region of the housing 4, but also in the transverse direction in the middle thereof, preferably formed immediately adjacent to a Gefach 26. For this purpose, 26 intermediate walls may be provided between the spacer element 30 and the Gefach, so that a formed for example on the upper housing part 6 locking lug between the partition and the adjacent boundary wall of the Gefaches 26 can enter and lock with a formed on the intermediate wall window opening. A corresponding embodiment is in the FIGS. 9 and 10 clarified. There said partition of the Gefaches 26 is designated by reference numeral 110. An intermediate wall is identified by reference numeral 112. The latching opening within this intermediate wall 112 is designated by reference numeral 114. A with the housing 2 closed in this locking opening 114 einfedernder locking web is in FIG. 10 denoted by reference numeral 116.

LIST OF REFERENCE NUMBERS

2

casing

4

Housing bottom

6

Housing top

8th

cover

10

opening

12

longitudinal web

14

radiator element

16

PTC heating element

18

PTC element

20

metal strip

24

heater

26

Gefach

30

spacer

31

web

32

Cover section

34

crosspiece

36

Air passage opening

38

Cover segment

40

recess

42

transverse spar

44

spring means

46

support element

48

sloping surface

50

fixing

52

ground

54

spring band

56

spacer rib

58

contact element

59

contact surface

60

accommodation space

62

slot

64

bearing element

66

holding rib

67

Cover surface

68

Displacement / counter element

70

spring means

72

support element

74

displacement

76

silicone cord

78

sloping surface

80

contact element

82

back

84

sliding surface

86

bearing protrusion

88

edition

90

spring means

92

counter-element

96

abutment projection

98

spring element

100

web

102

longitudinal slot

104

longitudinal slot

106

support element

108

sliding surface

110

partition wall

112

partition

114

latching opening

116

latching web

Claims (14)

Electric heating device with an open housing (2), in which a plurality of PTC heating elements (16) with adjoining radiator elements (14) are held in pretension against one another,
characterized,
that the housing (2) forms a plurality of compartments (26), wherein in individual compartments (26) each heating rods (24) formed from a PTC heating element (16) with both sides adjacent thereto radiator elements (14) are received and held under bias against each other , Electric heating device according to claim 1, characterized in that adjacent compartments (26) with housing cover sections (32) are closed, which are fastened to a lower housing part (4) and between a through the lower housing part (4) formed spacer (30) release, which neighboring areas (26). Electric heating device according to claim 2, characterized in that the spacer element (30) opposite to a bottom (52) of the housing lower part (4) in the thickness direction of the electric heater is formed inwardly offset. Electric heating device according to claim 2 or 3, characterized in that the spacer element (30) is provided with air passage openings (36). Electric heating device according to one of the preceding claims, characterized in that for each Gefach (26) a the elements of the heating element (14, 18, 20) under bias voltage setting spring element (44) is provided. Electrical according to claim 5, characterized in that the spring element (54, 76, 98) is formed from plastic. Electric heating device according to one of the preceding claims, characterized in that each separate heating elements (24) form a heating stage in compartments (26). Electric heating device according to one of the preceding claims, characterized in that all the PTC heating elements (16) and the radiator elements (14) of the electric heating device are each combined to form heating rods (24), each of the heating elements (24) being housed in a separate compartment (26 ) is provided. Housing (2) for an electrical heating device, in which a plurality of PTC heating elements (16) with adjoining radiator elements (14) can be accommodated under pretension against one another,
marked by
a housing lower part (4) which forms compartments (26) for receiving at least one PTC heating element (16) and on both sides fitting thereto radiator elements (14) comprising the heating element (24) and a spacer element (30) which the compartments (26) from each other spaced. Housing according to claim 9, characterized by adjacent compartments (26) covering the housing cover sections (32) which are connectable to the lower housing part (4) and between them the spacer element (30) release, which is formed by the lower housing part (4). Housing according to claim 10, characterized in that individual housing cover sections (32) are formed by separate housing cover segments (38). Housing according to claim 11, characterized in that the spacer element (30) relative to a bottom (52) of the housing lower part (4) in the thickness direction of the housing (2) is provided offset inwardly. Housing according to one of claims 11 or 12, characterized in that the spacer element (30) comprises a two compartments (26) interconnecting web (31). Housing according to one of claims 11 to 13, characterized in that the spacer element (30) has air passage openings (36).

Images