EP2017103B1 - Electric heating device - Google Patents

Description

The present invention relates to an electric heater, comprising a heating block, which is held in a housing opposite the frame openings forming and parallel layers of heat-emitting and heat-generating elements and with a respective frame opening covering and stiffening the housing grid arrangement.

Such a heater for air conditioning the interior of a motor vehicle is for example from the EP 1 564 503 The heat-generating elements of the heating block usually comprise a plurality of one above the other in a plane provided PTC heating elements, which are arranged between conductor tracks, which are usually formed by metal bands. These tracks are energized with different polarity. The PTC elements can be glued to these tracks. It is also possible to apply the printed conductors under prestress against the PTC heating elements. In any case, it must be ensured that there is good contact between the conductor tracks and the PTC heating elements for decoupling the heat generated by the PTC heating elements and for coupling in current.

One or more heat-generating elements may be provided as part of the heating block. The heat generated by the heat-generating elements is discharged through heat-emitting elements to the medium to be heated, ie the air. This flows through the housing through the two frame openings, which receive the flat heating block between them. The frame openings are usually parallel to each other on opposite sides of a substantially flat, frame-shaped housing. With a view to the most cost-effective production of the electric heater, the heat-emitting elements are usually formed of meandering bent metal strips that form corrugated fins. These corrugated ribs rest on one or both sides of heat-emitting elements. Accordingly, the heating block comprises a plurality of layers of heat-emitting and heat-generating elements, wherein care must also be taken with regard to the heat extraction that the heat-emitting elements abut well on the heat-generating elements. Also for this purpose, the heat-emitting elements can be firmly connected to the heat-generating elements and / or applied by at least one received in the housing spring element under bias.

Instead of a meandering sheet-metal strip, the heat-emitting element can also be formed by an extruded aluminum profile which forms webs which extend substantially perpendicular to the layers of the layer structure comprising the heat-emitting and the heat-generating elements. In such a case, the trace, i. the generally planar contact surface for the PTC heating element are formed by the outer surface of such an extruded aluminum profile. In both alternatives corrugated fin element or extruded profile, the contact surface for the PTC heating elements are designed to be electrically conductive and electrically connected to the housing usually held in isolation from each other held contacts. In the former case, the contacts are usually formed by the exposed ends of the metal strips.

The layered heating block of parallel heat-emitting and heat-generating elements, optionally with the addition of one or more parallel thereto extending spring elements is preferably held in a housing having a U-shaped cross-section. When loading the layer structure with a spring, the frame should be dimensioned so that the spring force can hold permanently even at the elevated temperatures. It should be noted that the insulating frame is nowadays produced not least for economic reasons as an injection molded part. Usual housing today consist of a lower housing part and a housing upper part. The lower housing part forms a receptacle for the individual elements of the heating block and, if necessary, the spring element. In this lower housing part, the individual elements of the heating block are arranged. Thereafter, the heating block is enclosed by joining the upper housing part and the lower housing part in the housing. For this purpose, edges surrounding the frame openings may partially cover the heating block, so that the heating block is enclosed between the frame openings and held in the housing. The two housing parts are then connected to each other, for example via a latching connection.

In this type of assembly, the problem arises that the individual layers of the heating block must be arranged at a predetermined location in the housing. Since not each heat generating element own contacts are assigned, the electrical conditions within the heating block must be taken into account during assembly. However, in order to reduce the production costs, there is also the desire to design the parts of the heating block as standardized as possible, so that identical components can be used for different positions of the heating block.

Furthermore, with regard to cost-effective production of the electric heater, the housing itself should be as simple as possible. However, the special requirements that the installation of one or more spring elements in the housing in practice, if in the joining of the housing parts of the heating block is already set in the frame under bias, so that the joining against this bias to took place.

With regard to the previously discussed problems is already with the EP 1 564 503 an electric heater of the generic type proposed in which the layers of the heating block including a spring element are first used without tension in a housing base. An upper housing part connectable therewith forms a bevelled sliding surface, which engages over the outside of the upper part of the spring element, which protrudes from the lower housing part, with respect to the heating block. When joining the upper housing part and the lower housing part, the spring element is accordingly urged in the direction of the heating block and applies under bias to this.

This prior art proposal leads to a certain ease of assembly, which, however, requires that the elements of the heating block as well as the spring element are placed in the correct position in the lower housing part. Furthermore, the realized in this electric heater housing has different inclined surfaces, which are required for the bracing and enclosing of the spring element when joining the housing parts.

The present invention is based on the problem of specifying an electric heater which can be produced more simply and thus more cost-effectively. The present invention further seeks to provide a heat generating element of an electric heater which is suitable for installation in the aforementioned electric heater. According to a further independent aspect of the present invention, the invention is intended to specify a housing which can be used as part of the electrical heating device according to the present invention and which is particularly suitable for accommodating the heat generating elements proposed by the present invention.

To solve the former problem, the present invention proposes an electric heater having the features of claim 1. This differs from the generic electric heater in that at right angles to the layers extending first struts of the grid assembly associated with the housing and extending parallel to the layers extending second struts are formed by the heating block.

In departure of the EP 1 432 287 B1 is formed with the present invention, the grid assembly not only by the two interconnected housing parts. Rather, the housing parts only those struts which extend at right angles to the layers of the heating block as first struts. The purpose of extending at right angles and referred to as second struts grid elements are formed by the heating block. The second struts serve a certain shielding of the heat-generating element, which usually comprises two parallel interconnects of different polarity and provided therebetween, juxtaposed PTC elements. The second strut should preferably cover the two interconnects in the region of the frame opening on the outside and thus prevent a foreign body penetrating from the outside through the frame opening and penetrating the air to be heated onto the longitudinal side of the heat-generating element causing a short circuit between the opposing interconnects.

The WO 03/086018 A shows a heating device according to the preamble of claim 1.

The first and second struts of the electric heating device according to the invention preferably each contribute to a certain stiffening of the grid arrangement, which passes through the frame openings. For this purpose, however, it is not necessary that the crossing perpendicular to each other provided struts are firmly connected. Rather, a certain form fit and / or a certain support of the first and second struts is sufficient for a certain stiffening of the grid arrangement.

The second struts are formed by the heating block, so that the position of the corresponding second struts in the housing is determined only by the installation situation of the layers of the heating block. This makes it easier to provide the second struts in the region of the heat-generating elements, for example, to cover the conductor tracks of different polarity frontally. Contrary to the prior art described above, there is no longer the problem of close tolerance matching between the geometric configuration of the housing on the one hand and the layers of the heating block, which are sometimes movable, but at least held with some play.

In view of this, it is proposed with a preferred development of the present invention to provide the second struts in sections between the first struts, in such a way that the first struts are each positively fixed between two sections of the first struts, which means that the first struts substantially perpendicular to its extent, d. H. parallel to the longitudinal extent of the second struts are only slightly or not movable and are therefore held in a form-fitting manner between the respective sections.

In the aforementioned refinement, the second struts can engage in recesses of the first struts adapted to the dimension of the second struts and thus produce a form-locking connection which fixes the two struts substantially immovably to one another. However, it has proved to be advantageous for the stiffening and in particular with regard to possible manufacturing tolerances to arrange the second struts in the longitudinal direction of the first struts with respect to these movable. This means in particular a slightly movable mounting of the two struts relative to each other, which allows the compensation of manufacturing tolerances or a certain yielding of the individual layers of the heating block, for example, to compensate for thermal expansion and / or in response to an externally acting on the heating block clamping force or more springs built into the housing.

The second struts can be designed as shielding components between or as part of the heat-emitting or heat-generating elements. Particularly reliable is an embodiment in which the second struts are formed directly by parts of the heat-generating element. It has proven to be advantageous to form the second struts by positioning frame made of an insulating material, which forms side by side receptacles for each forming at least one PTC heating element and which are arranged between interconnects on which abut the PTC heating elements electrically conductive. With this preferred development, the struts are formed as a unitary element with the heat-generating elements, so that a correct positioning of the struts can be ensured in a simple manner.

With regard to a good shielding of the electrical conductor tracks and with regard to a desired mechanical interaction and support of the two struts, it is proposed according to a preferred development of the present invention to apply the conductor tracks on both sides of the PTC elements, ie to provide the conductor tracks as elements which initially separate and detached from the PTC elements, and form the sections of the second struts so that they overlap the tracks outside and thus secure captive on the position frame. With this preferred embodiment, a pre-assembled assembly is created, which can be handled and installed as a unitary element in the manufacture of the electric heater.

In this case, the structural requirements that are placed on the sections or struts insofar for fixing the interconnects can be relatively low if the interconnects in the installed state by a heating block under spring tension in the housing holding spring device is applied against the PTC heating elements, as for example from the EP 1 432 287 as well as the EP 1 564 503 is known.

For material-friendly production of the second struts, it is proposed according to a further preferred embodiment of the present invention to form the top and bottom of the heat-generating elements between the sections of the second struts through the conductor tracks. The tracks are accordingly free between the sections of the second struts and are shielded only after installation in the housing of the first struts and thus covered. The development further allows a relatively flat structure of the electric heater using relatively many standardized components, such as metal strips as interconnects.

To solve the sibling aspect of the present invention, this is a heat-emitting element of an electric heater of the type mentioned above, which comprises a positioning frame made of an insulating material forming side by side receptacles for each PTC heating element, which are arranged between tracks where the PTC heating elements are electrically conductive. This from the EP 1 564 503 known heat generating element is further developed with the present invention, characterized in that the position frame surrounding the conductor tracks and limiting holding webs, which engage over the traces outside and abut against these. Accordingly, the holding webs fix the loosely placed and preferably realized in the form of Blechbändem strip conductors relative to the position frame, whereby a pre-assembled assembly is created, the parts are captively connected to each other. Accordingly, the heat generating element can be easily handled and easily inserted into the housing. Furthermore, the holding webs are applied to the conductor tracks, so that the elements of the heat-emitting element are closely connected to each other and also the PTC heating elements through Concerns are fixed to the inner sides of the conductor tracks in the receptacles, so that, for example, a plurality of PTC heating elements can be arranged and fixed in a receptacle at predetermined locations.

Preferred developments of the heat-generating element according to the invention are specified in claims 9 to 13.

The present invention further provides a housing of a heater into which the heat-generating element according to the present invention for manufacturing the electric heater of the present invention can be installed. This housing is characterized in that the frame openings are penetrated by struts which extend only at right angles to the layers of heat-emitting and heat-generating elements. Prior to assembly of the housing, this peculiarity of the struts results from a comparison between the configuration of the receiving openings for parts of the heating block, which may be provided at the front ends of the layers of the heating block, or the slots or other bushings for electrical conductors of the heating block, which are also usually the front side out of the heating block and out there into the housing with the orientation of the struts of the housing ..

A preferred embodiment of the housing according to the invention is specified in claim 15.

Fig. 1

eine perspektivische Seitenansicht eines Ausführungsbeispiels der elektrischen Heizvorrtichtung:

Fig. 2

eine Seitenansicht auf ein Gehäuseunterteil mit darin eingebautem Heizblock des in Fig. 1 gezeigten Ausführungsbeispiels;

Fig. 3

einen vergrößerten Ausschnitt der Darstellung gemäß Fig. 2;

Fig. 4

eine perspektivische Seitenansicht des in den Fig. 1 bis 3 gezeigten Ausführungsbeispiels;

Fig. 5

eine perspektivische Seitenansicht des Gehäuseoberteils der elektrischen Heizvorrichtung nach Fig. 1;

Fig. 6

eine perspektivische Explosionsdarstellung eines wärmeerzeugenden Elementes der elektrischen Heizvorrichtung nach Fig. 1;

Fig. 7

eine Schnittdarstellung entlang der Linie VII-VII gemäß der Darstellung in Fig. 6 eines montierten wärmeerzeugenden Elementes;

Fig. 8

eine perspektivische Seitenansicht eines Federelementes zur Verspannung des Heizblocks des in den Fig. 1 bis 7 verdeutlichten Ausführungsbeispiels;

Fig. 9

eine Seitenansicht eines Endes des Beispiels gemäß Fig. 1 vor dem Fügen der Gehäuseteile;

Fig. 10

eine Schnittansicht entlang der Linie X-X gemäß der Darstellung in Fig. 9;

Fig. 11

eine vergrößerte Detailansicht des Ausschnitts A in Fig. 10 und

Fig. 12a

bis e vergrößerte Detailansichten ähnlich zu der Ansicht gemäß Figur 11 in verschiedenen Stadien beim Fügen der Gehäuseteile.

Further details and advantages will become apparent from the following description of an embodiment in conjunction with the drawings. In this show:

Fig. 1

a perspective side view of an embodiment of the electrical Heizvorrtichtung:

Fig. 2

a side view of a housing base with built-in heating block of in Fig. 1 shown embodiment;

Fig. 3

an enlarged section of the illustration according to Fig. 2 ;

Fig. 4

a side perspective view of the in the Fig. 1 to 3 shown embodiment;

Fig. 5

a perspective side view of the housing top of the electric heating device according to Fig. 1 ;

Fig. 6

an exploded perspective view of a heat generating element of the electric heating device according to Fig. 1 ;

Fig. 7

a sectional view taken along the line VII-VII as shown in FIG Fig. 6 a mounted heat generating element;

Fig. 8

a perspective side view of a spring element for clamping the heating block of the in the Fig. 1 to 7 illustrated embodiment;

Fig. 9

a side view of an end of the example according to Fig. 1 before joining the housing parts;

Fig. 10

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

Fig. 11

an enlarged detail view of the section A in Fig. 10 and

Fig. 12a

to e enlarged detail views similar to the view according to FIG. 11 in various stages when joining the housing parts.

The Fig. 1 shows a perspective side view of an embodiment of the electric heater with a housing 2, consisting of a lower housing part 4 and an upper housing part 6. Both housing parts 4, 6 are positively connected to each other and take in a heating block 8, which arranged from a plurality of parallel layers to each other heat-generating elements 10 and heat-emitting elements 12 consists. The heat-emitting elements 12 are formed as corrugated rib elements of meandering bent sheet metal strip.

At one end face of the housing 2, this is surmounted by five contact tongues 15 arranged one above the other in the transverse direction. The contact tongues pass through slots 16 which are recessed on the housing 2 and which in each case receive a contact tongue and are predominantly formed by the housing lower part 4, but on one end side are completed by the upper housing part 6.

The housing 2 has two opposite frame openings, of which in Fig. 1 only the frame opening 16 formed by the upper housing part 6 can be seen formed by the lower housing part 4 frame opening is in Fig. 4 and identified by reference numeral 18. The frame openings 16, 18 are each interspersed with struts 20 which extend at right angles to the layers of the heating block 8 and connect the opposing longitudinal beams of the lower housing part 4 and upper housing part 8 with each other.

The Fig. 2 shows details of the heating block 8 and its inclusion in particular in the lower housing part 4 and shows the lower housing part 4 in a plan view with the housing upper part removed. The heat-emitting elements 12 are only incompletely shown at the respective end faces of the housing lower part 4. Accordingly, the illustration in Fig. 2 also a view of the frame opening 18 formed by the lower housing part 4 free.

As can be seen, the exemplary embodiment shown has four heat-generating elements 10, which are each accommodated in the housing lower part 4 in an insulating manner and with a certain mobility transverse to the layers of the layer structure (heating block 8). The lower housing part 4 has for this purpose fitting element receptacles 22 which open a receptacle 24, which is formed essentially by the housing lower part 4 and accommodates the heating block 8. At each end face of the lower housing part 4, two different types of fitting element receptacles 22a, 22b are provided in the exemplary embodiment shown (cf. Fig. 3 ). Corresponding to the geometry of the fitting element receptacles 22, the heat-generating elements 10 have at their front ends fitting elements 26a, 26b which respectively fit only in the corresponding corresponding fitting element receptacle 22a or 22b. In the present case, the corresponding fitting element receptacles 22 are matched to the fitting elements 26 provided corresponding thereto, that the heat-generating elements 10 are movable by a few tenths of a millimeter transversely to the longitudinal extent of the layers of the heating block 8 in the housing 2. The outer fitting elements 26a are designed as a hammer head and engage in correspondingly formed fitting element receptacles 22a. These are substantially shorter in the longitudinal direction of the heat-generating element 10 than the second, centrally provided fitting element receptacles 22a. The fitting elements 26b associated with these elongated fitting element receptacles 22b are rod-shaped and less wide than the hammer-head-like fitting elements 26a. Due to this particular configuration, the central heat-generating elements 10 do not fit in the outer positions for heat-generating elements 10 of the heating block. In appropriate Way, the outer heat-generating elements can not be arranged in the middle of the heating block, ie insert into the housing 2.

While the heat-generating elements 10 can not be used anywhere in the housing 2, the heat-emitting corrugated fin elements 12 are nonspecific and as lengths of a meandering curved first sheet metal strip as manufactured and cut from this continuous material to length. Each individual heat-emitting element 12 can be used at any position for a heat-emitting element within the heating block 8.

The fitting elements 26 are integrally formed on a positioning frame 28, which in the 6 and 7 can be seen and explained in more detail below with reference to these figures. The positioning frame 28 is made of an insulating material and serves for the positioning of PTC heating elements 30. In the present case, a receptacle 32 in the positioning frame 28 is recessed for each individual PTC heating element 30, which surrounds this PTC heating element and thus defines it. On both sides of the respective PTC heating elements 30, which are arranged side by side in a plane, are sheet metal strips 34, 36, which form electrical conductors for energizing the PTC heating elements 30 and via which the heat generated by the PTC heating elements to the heat-emitting elements 12 is passed by heat transfer. These lie directly on the metal bands 34, 36 at.

The front ends of the positioning frames 28 are extended beyond a fitting element web 38 beyond the position of the metal bands 34, 36. At the outer end of the fitting element webs 38 are the respective fitting elements 26 of the positioning frame 28. As the cross-sectional view along the in Fig. 6 illustrated line VII-VII (cf. Fig. 7 ), the vast extent of the position frame 28 in the width direction of the respective metal bands 34, 36 is taken. In cross-sectional view laterally next to the metal bands 34, 36, the positioning frame on holding webs 40 which are provided immediately adjacent to the lateral edge of the metal strips 34, 36 and the corresponding metal strips 34, 36 project beyond the top and these overlap on the outside, preferably with the tracks 34, 36 in contact and abut this. The holding webs 40 are formed in the embodiment shown in one piece by way of injection molding initially as a right angle to the main extension direction of the position frame 28 outgoing projections. The distance of opposing projections is selected so that the sheet metal strip 34 or 36 just fits between these projections.

The one-piece component thus produced by injection molding is then provided with the essential parts of the heat-generating element 10, i. the PTC heating elements 30 are inserted into the corresponding receptacle 32 and surrounded on both sides by the metal strips 34, 36. Thereafter, the projections are plastically deformed inwardly and so the interconnects 34, 36 formed across. Here, usually a hot forming is used, in which the holding webs 40 forming material locally in the area of the metal strips 34, 36 warms up and thus softened. The means used in each case can locally heat the position frame 28, for example by means of hot air or by heat conduction. In the case of heating by heat conduction, the heating effecting agent is preferably formed by a tool which simultaneously performs the transformation of the retaining webs 40.

The holding webs 40 are not continuous in the longitudinal direction of the heat-generating element 10, but are provided in sections 40.1 to 40.5. These sections 40.1 to 40.5 leave between them a passage 41 free, which is designed such that in each case a strut 22 in the width direction between the sections 40.1; 40.2; 40.3; 40.4 or 40.5 fits. The section formed by the passage 41, in any case, projects inwards in relation to the outer surface of the retaining webs 40 to such an extent that at least half the thickness of the struts 22 fits between the retaining webs 40 and is accommodated there.

However, there is a lack of a positive engagement between the struts 22 and the positioning frame 28 in a direction transverse to the layers of the heating block 8, so that a movement is transverse to the layers of the heating block 8 between the struts 22 of the housing parts 4, 6, the may also be referred to as the first strut, and the retaining webs 40, which may be referred to as the second strut 43.

The heat-generating element 10 is formed as a preassembled component and can thus be handled during assembly, without the risk that the conductor tracks 34, 36 or even the inserted in the position frame 28 PTC heating elements 30 are lost. It should be noted, however, that usually the holding webs only fix the metal strips 34, 36 in the position frame, but not with a contact force against the PTC heating elements 30 put, which is sufficient to energize the PTC heating elements 30 during operation safe. This is in any case effected in the embodiment discussed in the context of the present invention by a spring element, which will be described below with reference to the Fig. 8 to 10 will be explained in more detail.

First, however, will continue to discuss those features that ensure that parts of the heating block 8 can not be installed at any point within the housing 2.

As in particular the Fig. 3 and 6 can be seen, is a metal strip, namely in Fig. 6 shown sheet metal strip 34, bent out of the plane of the heat generating element 10 ago. Accordingly, an offset 42 results between the plane in which the sheet metal strip 34 abuts against the PTC heating elements 30, and a free end 44, which by repeated, but opposite bending extends parallel to the first-mentioned main portion of the sheet metal strip 34. Again Fig. 3 can be seen, this free end 44 is mechanically and electrically connected by a crimp 46 to the associated contact tongue 14.

In the Fig. 3 labeled with reference numerals 10.3 and 10.4 upper heat-emitting elements have an outgoing from the upper sheet metal strip 34 offset 42.3 and 42.4. The lower heat generating element 10.1 has a downwardly outgoing offset 42.1. The metal strips 34, 36 of the heat generating element 10 marked with reference numeral 10.2 are on both sides to form an offset 42.20 or 42.21 arc and each provided with a contact tongue 14. Due to these differences, it is possible to avoid exchanging the positions for the heat-generating elements 10.3 and 10.2 within the housing 2. In the present case, he allows the embodiment that due to the design of contact reeds 48, the two middle heat-generating elements 10.2 and 10.3 can be interchanged. A corresponding interchangeability is also given for the two outer heat-generating elements 10.1 and 10.4.

The previously mentioned with reference to Fig. 1 mentioned slits 15 go from the outside of the housing 2 and terminate in the opposite to the slots 15 each widened Kontaktzungenaufnahmen 48. Behind this Kontaktzungenaufnahme 48 turn a narrowed slot 50 is formed, which is a contact tongue 14 formed by punching sheet metal piece and the free end of the 44th can accommodate the associated sheet metal strip 34.

The lower housing part 4 can be molded in an injection mold that can be produced cost-effectively, since all areas significant for the housing 4 extend parallel or at right angles to the frame opening 18 of the housing lower part 4.

Thus, the lower housing part 4 initially substantially mutually perpendicular frame surfaces 52a-d, which surround the heating block 8 circumferentially and perpendicular to the plane containing the frame opening 18 includes. On the front side, on which the contact tongues 14 are brought out of the lower housing part 4, the corresponding frame surface 52b opens outwardly via four fitting element web receivers 54, whose main walls likewise extend at right angles to the plane containing the frame opening 18. A corresponding extension have those functional surfaces of the housing lower part 4, which form the contact tongue receptacle 48 and the here leading slots 15 and 50 substantially and those walls which limit the fitting element receptacle 22 and in Fig. 3 are shown. The receptacles 15, 22, 50 and 54 described above are bounded on the side of the lower housing part 4 by a bottom which runs parallel to the plane containing the frame opening 18 of the housing lower part 4. This receiving floor is in Fig. 4 designated by reference numeral 56. This bottom 56 also forms the inner surface of the struts 22 and edge-side stops 58, 60 for the yet to be explained spring element on the one hand and for the located on the opposite longitudinal side outer heat-emitting element 12 on the other. These stops 58 and 60 in turn are parallel to the plane which also contains the frame opening 18.

Parallel to this plane runs the inner surface of the lower housing part 4, which is formed frontally of the front ends of the walls, which form the fitting element receptacles 22 and the Reeds 48 recordings. On a longitudinal side of this upper edge is formed by spacers 62 which project beyond the frame surface 52c to the receptacle 24 and their function in the description of the spring element will be discussed below. Below this upper level of the inner surface of the lower housing part 4 are inner surfaces 63 of the two longitudinal members 64, 66 of the housing lower part 4, however, the edge-side stops 58, 60 extend beyond so far that the heating block 8 almost completely, i. with more than 70% of its height-wise extent in the housing lower part 4 is circumferentially taken. The longitudinal beams 64, 66 are penetrated by pin guides 68, 70, 72, which extend at right angles to the plane containing the frame opening 18. The pin guides 68, 70, 72 extend in sections substantially the entire longitudinal extension of the longitudinal bars 44, 66th

In the middle of the respective longitudinal beams 64, 66 is a pin guide 70 which is formed with a relatively short length and opens to a window 74, which at the Outside of the housing base 4 is located. Adjacent to this central pin guide 70, the pin guide 68 is provided, each extending over about 1/3 of the length of the longitudinal bars 64, 66. At the outer end of these pin guides 68 are in turn pin guides 70 with associated windows 74, as described above. In turn, relatively small pin guides 72 are formed on the end of the longitudinal beams 64, 66 extending from the inner surface of the longitudinal beams 64, 66 to the outer surface of the housing base, which also includes the frame opening 18.

The functional surfaces forming the pin guides 68, 70, 72 all extend at right angles to the plane containing the frame opening 18. Only the front edges of the corresponding openings 68 to 72 are slightly chamfered or rounded in order to facilitate the insertion of corresponding guide pins 76 to 80 of the upper housing part 6. To facilitate connection of the lower housing part 4 and the upper housing part, the free ends of the walls are further chamfered or rounded, which delimit the spacers 62 and the receptacles 22b, 15, 50, 48 at the end and form the upper ends of the spacers 62.

This in Fig. 5 shown in perspective housing upper part 6 also has only orthogonal or parallel to the corresponding housing opening 16 aligned functional and boundary surfaces. In particular, the guide surfaces of the previously mentioned guide pins 76, 78, 80 are provided as functional surfaces, which can be introduced into the corresponding pin guides 68, 70, 72. The guide pins 78 are formed as latching pins and form latching webs 82, which are surmounted on the upper side by a thickened head of the latching pin 78, which form a latching surface 86 which extends parallel to the plane which also contains the frame opening 16. The latching webs 82 are derived from the top of a cover 88, which is formed as a substantially planar member and the frame opening 16 predetermines and further includes the outer surface of the struts 22. The cover 88 is formed frame-shaped as a cover for the lower housing part 4. Accordingly, the guide pin 76 to 80 from the inside of the cover 88 are perpendicular from. For the locking webs 82, a bulge 90 is provided. In the area of the bulge 90, the edge surface of the cover 88 is retracted inwards, so that the flat planar side surface of the latching web 82 extends parallel to the guide surfaces of the guide pins 76 and 80, but inwardly to the respective outer guide surface of these guide pins 76, 80th lies. The the Heating block 8 facing inner surfaces of the corresponding guide pins 78 to 80 are, however, in a plane.

On one end side of the upper housing part 6, five recesses corresponding to the five contact tab receptacles 48 are formed on the inner wall of the cover, forming part of the slots 15 and also including an upper edge portion comprising contact blades 14 after mounting the heating block in the closed housing. On the opposite end side, a further guide pin 92 is provided, which cooperates with a corresponding thereto recessed on the lower housing part 4 further guide recess 94, but does not fit into the fitting element receptacles 22 and the Reeds 48, so that it is ensured that the upper housing part 6 in vorbestimmter and clearly placed on the lower housing part 4 and joined with this. The walls surrounding the further pin guide 94 and forming the guide pin 92 also extend at right angles to the plane lying on the frame opening 16 or 18.

The Fig. 8 shows a perspective side view of a spring element 96, which rests against the edge of the heating block 8 and is in its installed position at the height of the heating block 8. In the Fig. 8 front side of the spring element 96 forms a flat contact surface 98, at which the adjacent, in Fig. 3 uppermost heat-emitting element rests with its lamellae. More precisely, the ends, which are bent over at the ends, lie more meandering lamellae of the corrugated ribbed strip 12 against this contact surface 98. The abutment surface 98 is formed by a first flat sheet metal strip on which both sides transverse outgoing leg spring 100 have been formed by punching, which are initially within the plane of the contact surface 98 and after punching by bending in the as in the Fig. 8 . 10 . 11 and 12 recognizable shape have been brought. Two spring legs 100o, 100u lie in the width direction, ie transversely to the longitudinal extent of the planar contact surface 98 and thus in the insertion direction of the spring element 96 during assembly above the other. Each individual spring limb 100o, 100u forms an inclined sliding surface 102a, 102b, 102c, which in each case enclose an angle of between 35 and 55 °, preferably of approximately 45 °, between itself and the planar contact surface. Between the longitudinal direction of the spring element 96 successively provided pairs of spring legs 100 are flat segments 104, in which the spring element 96 is formed as a rectangular flat sheet metal strip.

This in Fig. 8 shown spring element 96 has pairs of spring legs 100o, 100u corresponding to the number of spaces between the individual spacers 62 on the longitudinal spar 64 (see. Fig. 4 ). Each pair of spring legs 100o, 100u is in the installed position of the spring element 96 between these spacers 62. The flat segment 104 bridges the width of the spacers 62 and connects adjacent spring leg pairs 100o, 100u together. The correspondingly produced spring can thus be introduced as a one-piece component into the housing 2, in particular in the housing lower part 4, which simplifies the production of the electrical heating device. The wall portions of the frame surface 42c provided between adjacent spacers 62 accordingly form a support surface 106 for the respective pairs of spring legs 100. Due to the vote of the spring element 100, especially the configuration of the flat segments 104 between the pairs of superposed spring legs 100, it is not possible to introduce the spring element 96 in the wrong orientation in the lower housing part 4. The spring element 96 can only be moved into its installed position, in which the spring element is accommodated at the level of the heating block 8 in the housing 2, when the flat contact surface 98 is aligned with the heating block. Furthermore, the heating block is held by the spacers 62 at a distance from the support surfaces 106, so that the spring element 96 can be applied to these surfaces at any time and without interference from the heating block 8 when inserted into the housing base 4.

With a progressive insertion movement of the spring element 96 in the direction of the heating block 8, ie with progressive introduction into the heating block, the spring element 96 is then forced urgently due to the spring force through the lower spring leg 100u in the direction of the heating block 8, so that the layers 10, 12th of the heating block are compressed. The flat contact surface 98 then already has such an overlap with the adjacent heat-emitting element 12, that the spring element 96 is sufficiently guided in the direction of insertion between the heating block 8 and the lower housing part 4 with progressive Einbringbewegung. As the introduction progresses, the lower spring leg 100u is finally elastically compressed. The housing-side counterforce is formed by an upper edge 108 which is formed between the support surface 106 and the inner surface of the longitudinal beam 64 through the joint of the two surfaces. When inserting the spring element 96, this edge 108 first urges the lower spring leg 100u inwards. With continuous insertion movement, finally, the upper spring leg 100o is chamfered by cooperation of the inward arch around the free end of the corresponding spring leg 100o pushed inwards.

Like that 10 and 11 can be seen, the housing 2 has a further housing element, which cooperates with the spring element 96. This further housing element is formed by an edge 110 of the housing top 6, which is formed between the inner surface of the cover 88 and a bottom 112 of the housing top 6, by the abutting edge of an outer edge 113 defining the bottom 112 of the housing top with the inner surface the cover 88. The height offset between this bottom 112 and the inner surface of the cover 88 takes into account the fact that the heating block 8 projects beyond the surface formed by the longitudinal bars 64, 66 surface 63, approximately the same length as the spacers 62nd the inner surface 63 of the longitudinal bars 64, 66 projects beyond. The edge 110 abuts an inclined sliding surface 102a of the spring element 96, which is formed by the upper spring leg 100o. As Fig. 10 and 12a it can be seen, is the upper end of the spring element 96 in a substantially pressure-free state at a distance from the bottom 112 of the upper housing part. 6

The description of the assembly is given below on the Fig. 12a to 12e directed. First, the individual layers 10, 12 are introduced into the lower housing part 4 Thereafter, the spring element 96 manually inserted a little way into the housing base, at least so far until the layers of the heating block 8 against each other and the spring element 96 sufficiently deep between the heating block 6 and the frame surface 52c is provided.

This initial insertion movement, in which the spring element 96 introduces substantially no spring preload in the heating block 8, the spring element 96 is guided over the heating block 8 facing end faces of the spacers 62, which cooperates with the flat segments 104 of the spring element 96. Due to the system of spring element 96 and spacers 62, the spring element is aligned with its flat contact surface 98 parallel to the layers 4, 6 of the heating block. After this first assembly step, the spring element 96 projects beyond the plane occupied by the heating block 8 by a length which is in Fig. 12a marked L. Thereafter, the upper housing part 6 is placed on the lower housing part 4. The guide pins 76, 78, 80, 92 in this case engage in the corresponding pin guides 68, 70, 72, 94 a. In this case, the spring element 96 initially remains essentially free of tension. In this state can already sufficient overlap between the guide pins and the corresponding recesses are achieved, so that the two housing parts 4, 6 can be moved relative to each other only in a linear direction. Thereafter, the joining of the housing parts 4, 6 under application of the spring force.

First, the spring legs 100o, 100u are slightly compressed until the bottom 112 of the upper housing part 6 abuts against the upper end of the spring element 96 (see. Fig. 12b ). The two edges 108 and 100 have already slid over a certain distance along the inclined sliding surface 102a and 102b. As a result, the upper spring leg 100o is elastically bent inwards so far that, as the insertion movement progresses, the free end of the leg 100o, which forms a further inclined sliding surface 100c in the center of the spring element 96, can pass the edge 108 reliably. Thereafter, a progressive joining movement between the two housing parts 4, 6 also leads to the entrainment of the spring element 96. Initially, only the edge 108 causes a further elastic bias of the lower spring leg 100u. This lower spring leg 100u is finally completely received between the support surface 106 and the heating block 8. When increasing the introduction of the spring element 96 in the lower housing part 4 but also the upper spring leg 100o is elastically deformed by interaction of the edge 108 with this upper spring leg 100o in the direction of the heating block 8 and accordingly causes a spring force. This elastic spring force is primarily caused by the fact that the edge 108 slides on the further inclined sliding surface 102c and urges the upper spring leg 100o in the direction of the heating block 8 (intermediate step between Fig. 12c and Fig. 12d ). The spring element 96 has reached its end position when the two housing parts 4, 6 abut each other with their respective surfaces facing each other. The spring element 96 is clamped and held in this installation position due to the spring tension between the heating block 8 and the frame surface 52c. If the spring element 96 is displaced by an unintentional force from the outside, in each case the stop 58 or the bottom 112 of the housing upper part 6 prevents the spring element 96 from being forced out of the housing 2.

Shortly before the two housing parts 4, 6 abut each other, the guided in the guide channels under slight elastic bending of the locking webs 82 in the pin guides 70 heads 84 are pushed outwards, so that their locking surface 96 against a locking mating surface Apply 114 or project them with a slight clearance, so that the two housing parts 4, 6 are captively fixed against each other.

As the above description makes clear, in the manufacture of the electric heating device according to the discussed embodiment, the spring element is brought into its installation position by closing the lower housing part and the upper housing part when closing the housing, in which the spring element is at the height of the heating block, i. is arranged in the plane which is also occupied by the heating block. Furthermore, the spring element is placed under spring preload only during insertion, and that only when the two housing parts 4, 6 are guided by positive engagement of the guide pins 76 to 80 in the corresponding pin guides 68, 70, 72 relative to each other. The structural design accordingly offers the possibility of stress-free to introduce the components of the heating block in the housing 24 formed by the housing 2. Only then is the spring tension, and in fact adjacent to each other and within limits against each other positioned housing parts 4, 6. Should it then due to the spring preload produced when joining the spring elements 4, 6 to a shift of the elements of the heating block 8 or even to herausdringen the Elements of the heating block 8 come out of the receptacle 24, these parts are held by the heating block 8 in the housing 2 enclosing parts of the housing parts 4, 6 and pushed back into the desired position when joining the housing parts 4, 6.

With regard to the structural design, the present invention is not limited to the described embodiment. For example, a spring element can be seen in front, which has a spring leg, which is initially substantially free of tension in the installed position. This spring element is introduced stress-free together with the heating block in the receptacle 24. The spring element has a spring leg, the spring leg forms a in the direction of the stop 58 outwardly and down obliquely inclined sliding surface forms, and indeed for a pin which cooperates with the spring element and the corresponding spring leg when joining the upper housing part and lower housing part under spring preload sets, so that the spring element is applied in total against the heating block 8 under spring tension. In this embodiment, the spring element is initially taken free of stress together with the heating block in the lower housing part and remains stationary when generating the spring preload relative to the joining direction. The spring element is slightly displaced only in the plane of the heating block and applied to the heating block. Furthermore is the or the spring leg pivoted to produce the elastic bias.

The particular design of the heat generating elements 10 allows for easier assembly, since the grid assembly formed by the first and second struts 20, 43 is not completely part of the housing, but the second struts are formed with the frame 28 and thus is located where the PTC heating elements 30 come to rest within the heating block 8. Compared to the known prior art, in which the grid assembly are formed solely by the housing parts, housing parts can be produced accordingly, which are relatively simple. Furthermore, it is possible to work with higher tolerances since there are no struts connected in one piece with the housing, which stretches parallel to the layers of the heating block 8 and must be provided exactly at the position of the heat-generating elements 10. By dimensioning the struts 20 and the passage 41 and in particular the insertion of the struts 20 between two sections of the holding webs 40, however, there is the possibility of the first and second struts 20, 43 form-fitting support against each other and thus stiffen the housing as a whole.

Since the heat-emitting element 12 is prepared as a preassembled unit and further ensured by the fitting elements 26 and the associated receptacles 22 that the heat-generating elements 12 can be installed only at predetermined locations within the housing 2, the manufacture of the electric heater, in particular the assembly of the items also be done by less experienced staff.

The specific embodiment of the embodiment provides an unambiguous assignment of different components of the electric heater. If this clear assignment is not met, the components of the electric heater can not be mounted.

LIST OF REFERENCE NUMBERS

2

casing

4

Housing bottom

6

Housing top

8th

heating block

10

heat generating element

12

heat-emitting element

14

contact tongue

15

slot

16

Frame opening, housing top

18

Frame opening, lower housing part

20

Strut / first strut

22

Pass element receptacle

24

Recording for the heating block

26

pass element

28

position frame

30

PTC heating element

32

Mount for PTC heating element

34

metal strip

36

metal strip

38

Pass bridge element

40

retaining webs

40.1 to 40.5

Sections of the retaining bars

41

passage

42

offset

43

Second strut

44

free end of the sheet metal strip 34

46

Vercrimpungselement

48

Contact tongue receiving

50

slot

52

frame surface

54

Shim web recording

56

ground

58

edge-side stop spring element

60

Edge-side stop heat-emitting element

62

spacer

63

Inner surface of longitudinal spar

64

longeron

66

longeron

68

pin guide

70

pin guide

72

pin guide

74

window

76

spigot

78

spigot

80

spigot

82

latching web

84

head

86

Rest area

88

cover

90

bulge

92

another guide pin

94

further pin guide

96

spring element

98

level contact surface

100

spring leg

102

sliding surface

104

flat segment

106

support surface

108

edge

110

edge

112

Bottom of the housing top

113

outer edge of the floor 112

114

Rest counter surface

L

longitudinal section

Claims (6)

1. An electric heater, comprising
   a planar coated heating block (8) which is held in a housing (2) defining opposite frame openings (16, 18) and includes parallel layers of heat-emitting elements (12) and heat-generating elements (10),
   first struts (20) extending at right angles with respect to the layers, covering the respective frame openings (16; 18) and assigned to the housing (2), and
   second struts (43) extending parallel with respect to the layers and defined by the heating block (8), wherein said second struts (43) extend in sections between the first struts (20) so that the first struts (20) are each fixed between two sections (40.1 - 40.5) of the second struts (43),
   characterized in that
   the first and second struts (20; 43) form a grid arrangement ((20; 43) reinforcing the housing (2).
2. The electric heater according to claim 1, characterized in that the second struts (43) extend in sections between the first struts (20), so that the first struts (20) are each fixed between two sections (40.1 - 40.5) of the first struts (20) in a form-closed manner.
3. The electric heater according to claim 1 or 2, characterized in that the second struts (43) are defined by a positional frame (28) made of an insulating material, which defines receptacles (32) provided side by side each for at least one PTC heating element (30) and which is arranged between conductor paths (34, 36) against which the PTC heating elements (30) are placed in an electrically conductive manner.
4. The electric heater according to one of the preceding claims, characterized in that the conductor paths (34, 36) rest on both sides of the PTC heating elements (30) and that the sections (40.1 - 40.5) of the second struts (43) externally overlap the conductor paths (34, 36).
5. The electric heater according to claim 3 or 4, characterized in that the conductor paths (34, 36) abut on the PTC heating elements (30) by means of a spring device (96) holding the heating block (8) in the housing under a spring pretension.
6. The electric heater according to one claims 3 to 5, characterized in that the upper and lower side of the heat generating elements (30) between the sections (40.1 - 40.5) of the second struts (43) are defined by the conductor paths (34, 36).

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