EP2017547B1 - Electric heating device - Google Patents

Description

The present invention relates to an electric heater, which is used in particular as a heater in a motor vehicle for heating air, with a heating block, which is held in an opposite frame opening forming housing and comprises parallel layers of heat-emitting and heat-generating elements. In particular, the present invention relates to an electric heating device with the preamble features of claim 1.

Such a heater for air conditioning the interior of a motor vehicle is for example from the EP 1 564 503 known. 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 strips. 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.

The EP 1 432 287 A discloses an electric heater having a housing (2) made of half-shells (2a; 2b) that can be plugged together. Each of the housing half-shells (2a, 2b) comprises latching tabs (32a) and latching pins (31) arranged alternately next to each other in a region close to their longitudinal side, projecting from the respective housing half-shell (2a, 2b) and having associated latching pins (31) and latching tabs (32a ) of the other housing half-shell (32b, 32a) cooperate in such a way that they lock together when assembling the housing half-shells (2a, 2b). Between each adjacent latching tabs (32a) and latching pins (31), the housing half-shells (2a, 2b) have a supporting element (33) pointing to the longitudinal side of the housing half-shell (2a, 2b), which has a housing side wall (35, 36) on the outside with an inside provided Side wall connects, which is provided on the opposite to the latching tabs (32a) and latching pin (31) side.

The EP 1 652 704 discloses an electric heater comprising a housing (20) having a housing bottom (20 ') and a housing top (20 ") configured as a lid, the housing bottom (20') and housing top (20") being secured to the housing (20) ) provided latching connections (21) with the insertion of a heating element (2) are firmly connected to each other. The snap-in connections (21) are formed by webs projecting at a predetermined distance from the edge of the housing upper part (20 ") with outwardly pointing latching lugs which, in an assembled state of the housing (20), engage with corresponding recesses in one the lower housing part (20 ') are circumferential housing side wall.

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.

To solve this problem, the present invention proposes an electric heater having the features of claim 1.

With the present invention, in view of an easy production of the heating device according to the invention, in particular with regard to an injection molding production of the housing, proposed, the recording and the pin guide forming Function surface and the outer contour predetermining contour surfaces of the housing base and the guide pin forming functional surfaces and the cover limiting boundary surfaces of the housing base exclusively form so that they extend parallel or perpendicular to the frame opening comprehensive level. In the following description of the invention, reference will be made to the plane comprising the frame opening. With this reference, reference will also be made to the parting plane of the injection molding tool for the manufacture of the housing elements. However, since the frame opening of the housing extends parallel to the corresponding division plane, this reference seems appropriate and with regard to a description of the housing or the electric heater after removal from the injection mold required to describe the invention in terms of their physical-spatial design. This embodiment has the advantage that an injection molding tool for producing the lower housing part and the upper housing part by means of injection molding of thermoplastics has no undercuts and due to the orthogonal orientation of the functional, contour and boundary surfaces of the housing parts mold surfaces, ie the injection mold a total of means End mill can be easily made. Turning away from complicated injection molds with a spark-eroded, the mold cavity forming mold cavity surface, accordingly, the injection mold for the production of the housing of the heater according to the invention can be inexpensively and without special know-how create.

As functional surfaces in the context of the invention, those surfaces of the housing parts are considered, which limit the receptacle for the heating block, allow the joining of the housing parts and lead the required relative movement of the housing parts. As contour and boundary surfaces in the context of this invention, those surfaces of the housing parts are considered, which define the outer contour of the housing parts and the housing as a whole. Relatively narrow end faces or edge surfaces on which two flat surfaces abut against one another at right angles do not count as corresponding functional, contour and boundary surfaces in the sense of the invention. These faces and edge surfaces may be rounded or chamfered.

The housing is formed in the present invention of this preferred embodiment usually as a rectangular member which surrounds a substantially also substantially rectangular receptacle for the heating block and at its both outer sides each also defines a likewise likewise substantially rectangular housing opening.

The lower housing part has for this purpose a parallel to the corresponding housing opening extending contact surface, which also forms a functional surface according to the invention and against which the heating block is applied after insertion into the lower housing part. On the opposite side of the lower housing part, the pin guides are exposed. These pin guides are formed in at least one of the spars, preferably on the opposite longitudinal beams of a frame member of the housing base, which surrounds the heating block circumferentially and includes in it. This frame element forms the majority of the housing base. Only in the region of the frame opening, which is formed by an end face of the frame member, extending struts, the receiving opening and enforce between the outside of the housing and the heating block are provided after it is inserted into the lower housing part.

The upper housing part consists essentially of a cover which extends the other, parallel to the frame opening formed by the frame member and is likewise interspersed with struts, preferably corresponding to the struts of the housing lower part. This cover is a substantially flat component with only parallel or orthogonal to the frame opening of the upper part extending surfaces. From the inward surface of the cover protrude the guide pins, which accordingly extend web-shaped perpendicular to the plane containing the frame opening. Preferably, these guide pins are predominantly, if not exclusively provided on the long sides. At one, optionally on both transverse sides of the upper housing part may further be provided a pin which cooperates with a corresponding thereto formed on the lower housing part recess, which is missing on the opposite transverse side of the housing base, so that the upper housing part makes sense only in a certain orientation with the lower housing part can be connected.

The housing of the electric heater of the present invention preferably consists solely of the two housing parts, ie housing upper part and lower housing part. By welding, gluing or clipping on a front side of the housing, which is surmounted by electrical connection elements, a mounting flange and / or a control housing for controlling the heating block can be attached. These additional components are usually not part of the housing of the electric heater according to the invention. Their housing has a flat, simple, rectangular, box-shaped outer contour in a simplified embodiment.

The lower housing part usually forms the receptacle for the heating block. If this is held under spring preload in the housing, it is proposed according to a preferred embodiment of the present invention that the lower housing part forms contact surfaces for the at least one spring element with which the heating block can be held under pretension in the receptacle. These contact surfaces extend only parallel or perpendicular to the plane surrounding the frame opening. It usually extend those contact surfaces for the spring element, which resist the spring force, strictly perpendicular to the plane which also contains the frame opening. In addition, and in a relatively small extent, one or more abutment surfaces are furthermore provided as abutment surfaces for the at least one spring element, against which the spring element abuts, after it has been inserted into the housing lower part. The stop surfaces thus provide the lowest position of the spring element in the lower housing part.

According to a further preferred embodiment of the present invention, selected guide pins are designed as latching pins. This means, first of all, that a surface of the latching pin which extends parallel to the movement of the joining of the lower housing part and the upper housing part lies in that plane which also encompasses the other guide surfaces of the latching journal. Accordingly, the locking pin also serves to guide the relative movement when joining the lower housing part and the upper housing part. According to a special feature of the present invention, the latching pin for connecting housing upper part and housing lower part opens with its latching surface in a window, which is formed on the outside of the housing base, namely where the associated pin guide opens. The latching surface of the latching pin also extends with respect to an easy production of the injection molded plastic housing parallel to the plane comprising the frame opening. A corresponding extension has the latching counter surface formed by the window.

To further simplify the production of the injection mold, it is proposed according to a further preferred embodiment of the present invention that a latching ridge of the latching pin projecting beyond the latching surface goes off from the outer surface of the cover and in a bulge which is formed on the outer edge of the cover. The latching web preferably extends from the frame opening containing Level up to the locking surface and parallel to the guide surfaces of the guide pin. In this respect, the preferred development of the present invention allows a simple machining, for example, with an end mill as the locking pin-forming tool surface of the injection mold. As a bulge in this embodiment is preferably to understand a contour that jumps from the cover circumferentially surrounding forehead separation surface or edge side inwards and at least in the region of the detent surface dominated by the outer surface of the detent web.

Fig. 1

eine perspektivische Seitenansicht eines Ausführungsbeispiels der elektrischen Heizvorrichtung;

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 Ansicht gemäß Figur 11 in verschiedenen Stadien beim Fügen der Gehäuseteile.

Preferably, all surfaces of the two housing parts extend exclusively parallel or perpendicular to a plane containing the frame opening. Insofar as the frame opening is used as the reference plane, this takes place in view of the knowledge that the frame opening forms the bottom of an injection mold for forming a lower housing part or upper part and, in any case, lies parallel to the parting plane of the injection mold. In this respect, the reference to the frame opening means at the same time a reference to the parting plane of the injection mold. Only edge surfaces between surfaces meeting at right angles or end faces of housing parts can be chamfered or rounded off according to a preferred embodiment of the present invention by milling or grinding the injection molding tools that demould the edge or end faces. These end faces include, for example, the end-face end faces of the guide pins, ie the front guide surfaces of the corresponding guide pins or the end faces of the guide pins which extend parallel to the insertion direction. Further details and advantages of the present invention will become apparent from the following description of an embodiment in conjunction with the drawings. In this show:

Fig. 1

a side perspective view of an embodiment of the electric heater;

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 heater 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 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 14 arranged one above the other in the transverse direction. The contact tongues 14 pass through recesses 15 which are recessed on the housing 2 and each receive a contact tongue 14 for themselves and are predominantly formed by the housing lower part 4, but are rounded off at one end by the housing upper 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. The 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 front ends 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 10 can not be arranged in the middle of the heating block 8, ie insert into the housing 2.

While the heat-generating elements 10 can not be used at any point in the housing 2, the heat-emitting corrugated fin elements 12 are non-specific and manufactured as lengths of a first meandering bent sheet metal strip 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 12 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 grips this PTC heating element 30 circumferentially 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 30 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 frame 28 are extended over a fitting element web 38 on the position of the metal strips 34, 36 addition. 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 receptacles 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 formed continuously 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 20 in the width direction between the sections 40.1; 40.2; 40.3; 40.4 or 40.5 fits. In any case, the section formed by the passage 41 projects inwards in relation to the outer surface of the retaining webs 40 so far that at least half the thickness of the struts 20 fits between the retaining webs 40 and is received there.

However, there is a lack of a positive engagement between the struts 20 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 20 of the housing parts 4, 6, the may also be referred to as first strut 20, and the retaining webs 40, which may be referred to as a 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. 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, the embodiment allows that the two middle heat-generating elements 10.2 and 10.3 can be interchanged with one another due to the design of contact tongue receivers 48. 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. At the end face on which the contact tongues 14 are led out of the lower housing part 4, the corresponding frame surface 52b opens outward 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 20 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 extends the inner surface of the lower housing part 4, which is frontally formed by 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 beams 64, 66 of the housing base 4, however, extend beyond the edge-side stops 58, 60 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 extent of the longitudinal bars 64, 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. At the front ends of the longitudinal beams 64, 66 turn relatively small pin guides 72 are formed, which extend from the inner surface of the longitudinal bars 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 6, the free ends of the walls are further chamfered or rounded, which delimit the spacers 62 and the receptacles 22b, 15, 50, 48 at their ends 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 20. 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 76 to 80 are, however, in a plane.

On one end side of the housing upper part 6, five recesses corresponding to the five contact tongue receptacles 48 are formed on the inner wall of the cover, which form part of the slots 15 and also an upper edge region of the contact tongues 14 after mounting the heating block 8 in the closed housing 2 include. 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 of the meandering lamellae of the corrugated ribbons 12, which are bent over at the ends, bear 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. Every single spring leg 100o. 100u forms inclined sliding surface 102a, 102b, 102c, each of which encloses between itself and the planar contact surface an angle of between 35 and 55 °, preferably of about 45 °. 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 96, 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 installation position, in which the spring element 96 is received at the height of the heating block 8 in the housing 2, when the flat contact surface 98 is aligned with the heating block 8. Furthermore, the heating block 8 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 8, the spring element 96 is then forced inevitably due to the spring force through the lower spring leg 100u in the direction of the heating block 8, so that the layers 10, 12 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 the bottom 112 of the housing top 6 delimiting outer edge 113 with the inner Surface of 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 63 formed by the longitudinal beams 64, 66, approximately the same length as the spacers 62, 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 is manually inserted a little way into the lower housing part, at least until the layers of the heating block 8 against each other and the spring element 96 is provided sufficiently deep between the heating block 6 and the frame surface 52c.

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 10, 12 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 110 have already slid over a certain distance along the inclined sliding surfaces 102a and 102b. As a result, the upper spring leg 100o is already elastically bent inwards so that, as the insertion movement progresses, the free end of the leg 100o, which forms a further inclined sliding surface 102c 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, guided in the guide channels with slight elastic bending of the locking webs 82 in the pin guides 70 heads 84 are urged outwards, so that their locking surface 86 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 illustrates, in the manufacture of the electric heater according to the discussed embodiment, the spring element 96 is spent in closing the housing 2 by joining the lower housing part 4 and upper housing part 6 in its installation position in which the spring element 96 is at the height of the heating block 8 ie is arranged in the plane which is also occupied by the heating block 8. Furthermore, the spring element 96 is placed under spring preload only during insertion, namely 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 introducing the components of the heating block 8 free of stress in the receptacle 24 formed by the housing 2. Only then does 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 when joining the housing parts 4, 6 to a shift of the elements 10, 12 of the heating block 8 or even a protrusion of the elements 10, 12 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. Thus, for example, a spring element 96 may be provided, which has a spring leg 100, which is initially essentially free of tension in the installed position. This spring element 96 is introduced stress-free together with the heating block 8 in the receptacle 24. The spring element 96 has a spring leg 100, the spring leg 100 forms a in the direction of the stop 58 outwardly and downwardly inclined sliding surface 102 forms, for a pin which cooperates with the spring element 96 and the corresponding spring leg 96 during joining of the upper housing part 6 and lower housing part 4 is spring preloaded, so that the spring element 96 is applied in total against the heating block 8 under spring preload. In this embodiment, the spring element 96 is initially taken free of stress together with the heating block 8 in the lower housing part 4 and remains stationary when generating the spring preload relative to the joining direction. The spring element 96 is slightly displaced only in the plane of the heating block 8 and applied to the heating block 8. The vastness

Ren, the spring leg or 100 is pivoted to produce the elastic bias. The particular design of the heat generating elements 10 allows for easier installation, since the grid assembly formed by the first and second struts 20, 43 is not completely part of the housing 2, but the second struts 43 are formed with the frame 28 and thus is reliably there 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 20 integrally connected to the housing 2, which extend 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 positively support one another and thus stiffen the housing 2 in total.

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 the longitudinal bars

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 (5)

1. Electric heating device, in particular as a supplementary heater for motor vehicles, with a housing (2) forming oppositely situated frame openings (16; 18), in which a heating block (8) having at least one radiator element, at least one PTC heating element (30) comprising at least one heat-emitting element (12) is accommodated, and in which several contacts (14) electrically connected to the at least one PTC heating element (30) are kept isolated,
   and the housing (2) comprises a housing bottom part (4) forming a receptacle (24) for the heating block (8) and a frame surrounding the receptacle (24), and a housing top part (6) which is connected to the housing bottom part (4) in order to enclose the heating block (8) and has guide pins (76, 78, 80) which are integrally formed with and project out from a cover (88) of the housing top part (6) enclosing the heating block (8) and engage with guide orifices co-operating therewith, recessed into the housing bottom part (4), which are formed in oppositely lying longitudinal slats (64, 66) of the housing bottom part (4) and form pin guides (68, 70, 72) for the guide pins (76, 78, 80),
   characterised in that
   the functional surfaces constituting the receptacle (24) which bound the holder for the heating block (8) and the functional surfaces forming the guide pins (76, 78, 80) and pin guides (68, 70, 72) which enable the housing parts (4, 6) to be joined and guide the relative movements of the housing parts (4, 6) necessary for this purpose, as well as the contour surfaces defining the external contour of the housing bottom part (4) and the boundary surfaces of the housing top part (6) bounding the cover (88) extend exclusively parallel with or perpendicular to the plane incorporating the frame opening (16; 18), and the contour and boundary surfaces are the surfaces defining the external contour of the housing parts (4, 6) and housing (2), with the exception of narrow end faces and edge surfaces at which two planar surfaces meet one another at a right angle.
2. Electric heating device having at least one spring element (96) accommodated in the housing (2), through which the heating block (8) is held under pretension in the housing (2), as claimed in claim 1, characterised in that the housing bottom part (4) forms abutment surfaces (52c; 58; 106) for the at least one spring element (96) which extend exclusively parallel with or perpendicular to the plane comprising the frame opening (18).
3. Electric heating device as claimed in claim 1 or 2, characterised in that selected guide pins are formed as notched pins (78), that the pin guides (70) assigned to these notched pins (78) open into a window (74) opening towards the external face of the housing bottom part (4), and that latching surfaces (86) provided on the notched pins (78) and latching counter surfaces (114) afforded by the window (74) extend at a right angle to the plane comprising the frame opening (16).
4. Electric heating device as claimed in claim 3, characterised in that a web (82) of the notched pin (78) projected by the latching surface (86) and supporting the latter extends from the external surface of the cover (88) and merges into an indentation (90) formed in the outer edge of the cover (88).
5. Electric heating device as claimed in one of the preceding claims, characterised in that only the edge surfaces (108, 110) between surfaces or end faces of housing parts meeting one another at a right angle are chamfered or rounded by milling or grinding.

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