EP3101998A1 - Ptc heating element and electric heating device containing such a ptc heating element and method for manufacturing an electric heating device - Google Patents

Abstract

The present invention relates to a PTC heating element (2) with at least one PTC element (4) which is provided between conductor tracks (6). In order to reduce the clearance and creepage distance between the two interconnects (6), the present invention proposes an insulating mass (10) which completely seals off at least one of the interconnects (6) and / or the PTC element (4). In the case of the electrical heating device according to the invention, such a PTC heating element is electrically conductive on heat-emitting surfaces of the heating device. According to the inventive method for producing an electrical heating device, the conductor tracks (6) are glued to the PTC element (4) for generating a PTC heating cell (7). Thereafter, the PTC heating cell (7) between two electrical insulating layers by a circumferentially around at least one of the conductor tracks (6) and / or the PTC element (4) applied insulating compound (10) sealed.

Description

The present invention relates to a PTC heating element with at least one PTC element which is provided between conductor tracks.

Such a PTC element is used, for example, in electric auxiliary heaters in motor vehicles. These heaters are used to heat air. They have on opposite sides of the PTC element adjacent Wellrippenlagen. Usually several layers of stacked PTC elements are provided with adjacent corrugated fin layers. Examples of the prior art for such air heaters are for example the EP 1 768 459 A1 . EP 2 109 345 B1 such as EP 1 768 568 A1 ,

However, generic PTC heating elements are also used in heaters for heating liquid media, as used for example in EP 1 921 896 A1 are described.

Basically, the problem arises of a good Wärmeaustrags. The PTC elements have self-regulating properties. If the heat generated by the PTC element is not well dissipated, the electrical performance of the PTC element can not be fully utilized.

The present invention is based on the problem to provide an improved PTC element and an improved electric heater. Furthermore, the present invention proposes to produce an electric heater.

To solve the device-related problem, the first aspect of the present invention proposes to seal off at least one of the conductor tracks and / or the PCT element at the end with an electrically insulating mass.

Particularly in high-voltage applications, for example when installing the PCT heating element in an electric heater for an electrically driven motor vehicle, the problem of electrical flashovers, for example by air and / or Creepage distances. This problem is addressed by the present invention in that at least one of the conductor tracks, preferably this one conductor track and the PTC element abutting one side thereof is sealed in a mass at the end. In this case, the free end face of the conductor tracks is usually completely absorbed in the mass. The front side of the PTC element can only be partially absorbed in the mass and thus covered by this. The conductor usually ends flush with the outer peripheral surface of the PTC element. Only electrical connection lugs usually protrude on one side beyond the PTC element. These terminal lugs are located at opposite ends of the PTC element and serve to energize the same with different polarity.

This insulating composition usually comprises a silicone composition as the liquid phase. The liquid phase is preferably formed by an addition-crosslinking 2-component silicone which cures at room temperature and cures under pressure under heat. The mass has a viscosity at 25 ° C of between 100 and 200 Pa s. In view of a good flowability, the 2-component silicone is usually mixed with benzene or toluene as a diluent to obtain a viscosity at 25 ° C in a range of between 4 and 15, preferably between 5 and 8 Pa s. The thermal conductivity of the mass (liquid phase + particles) is regularly between 3.0 and 5.0 W / (m K). When crosslinked, the liquid phase constituent of the composition should have a hardness Shore A of about 10-40 and a dielectric strength CTI> 600. This liquid phase is usually admixed with a predetermined solids content with high thermal conductivity. The thermal conductivity of the filler should be between 20 and 30 W (m K). The filler is preferably alumina. With a view to good flow properties, spherical alumina having an average particle size of about 4 to 6 μm is preferred. With a view to a good thermal conductivity of the mass (liquid phase + filler content), the mass has a filler content of at least 50% by volume, particularly preferably between 85 and 95% by volume.

Due to the insulating mass, the individual components of the PTC heating element are preferably joined into one unit. The PTC heating element according to the present invention preferably has no frame that inserts and / or surrounds the components. According to a preferred development of the present invention, the PTC element has an insulating layer which projects beyond the conductor end and which, with the conductor track and / or the PTC element, predetermines a receiving region receiving the insulating compound. The insulating layer is an electrical insulating layer. It may consist of a hybrid film comprising a polyimide film and an applied thereon electrically insulating, however, preferably good thermal conductivity mass as the second layer of the insulating layer. This mass preferably has the same material quality as the electrical insulating compound for sealing in the conductor track.

The insulating layer usually towers on all sides of the PTC element. As a result, a gusset is formed respectively between the PTC element and the insulating layer, which forms the aforementioned receiving area. In this gore-shaped receiving area, the electrically insulating material can be introduced and cured there.

The PTC heating element according to the invention is produced as a separate component and adapted for insertion into an electrical heating device, in particular for insertion into a U-shaped recess of a heater housing. This U-shaped recess preferably starts from a dividing wall which separates a circulation chamber from a connection chamber. The U-shaped recess is provided within a heating rib, which projects from the dividing wall into the circulation chamber and limits the U-shaped recess in a fluid-tight manner with respect to the circulation chamber. The recess opens only to the connection chamber. The circulation chamber is adapted adapted to receive a liquid medium, i. sealed and provided with inlet and outlet for connecting the circulation chamber to a circuit for liquid medium. The electric heating device has a preferably trough-shaped housing lower part, which encloses the circulation chamber between a housing bottom, the partition wall extending parallel thereto, and housing sidewalls extending at right angles thereto. From the side walls of the housing base projecting connecting pieces for connecting the electric heater to a circuit for a liquid medium. These connecting pieces are sealingly connected to the housing side walls. The lower housing part may be formed of plastic. The circulation chamber is formed liquid-tight.

The filling volume of the circulation chamber in water heaters of the type described above is between 450 ml and 200 ml, preferably between 400 ml and 220 ml and more preferably between 300 ml and 230 ml. This filling volume also includes the filling volume of the nozzle. Each nozzle itself has a filling volume of about 7 ml. The embodiment shown is usually integrated in a cooling water circuit in a vehicle having a volume of about 5 to 6 liters. In this cooling water circuit, at least one heat exchanger for the heating of air in the passenger compartment can be integrated. Additionally or alternatively, the cooling water circuit heat exchanger surfaces to technical components of an electric vehicle have to bring them to the required operating temperature at cold ambient temperatures. Thus, the PTC element according to the invention is used in particular in a heater of an electrically driven motor vehicle, in which liquid medium is heated, for example, to heat an aggregate or the interior of the electrically operated vehicle. In such an application, the PTC heating element is energized with a high voltage that care must be taken here in a special way, the creepage and / or clearance are eliminated.

With a view to a good heat-conducting introduction of the PTC element in such a U-shaped recess, the PTC element is preferably wedged in the recess, as shown in EP 2 637 475 A1 or the EP 1 921 896 A1 is known. For this purpose, according to a further preferred embodiment of the present invention, a sliding plate is proposed, which can be connected, for example glued, to the PTC element via the electrically insulating mass. This results in a prefabricated intermediate product, which can be used as a unit in the U-shaped recess. The intermediate product consists of the PTC element and the conductors provided on both sides. These interconnects are usually formed by contact plates. The conductor tracks are connected to the PTC element, preferably glued. At opposite free surfaces of the conductor tracks are preferably provided each insulating layers. Thus, the PTC heating element, ie the PTC element and the conductor tracks resting on both sides, is enclosed between the two insulating layers. Said sliding plate bears against one of the insulating layers.

The sliding plate preferably projects beyond the PTC element as well as the conductor tracks. Furthermore, the sliding plate preferably projects beyond one of the insulating layers at the end and overlaps this insulating layer with a leg which extends at a distance from the PTC element at the bottom. A gap formed between the leg and the PTC element is completely or partially filled with the electrically insulating mass. The corresponding leg of the sliding plate preferably forms a stop which determines the penetration depth of the PTC heating element into the U-shaped recess. In this case, the insulating layer, which protrudes over the conductor track at least on the underside, provides a minimal distance between the sliding plate and the PTC element. This distance is preferably between 2.5 and 4 mm.

According to a preferred embodiment of the present invention, the sliding plate is formed at least by punching and bending of a sheet material and has a formed by this machining spacers. By this spacer, the PTC heating element is held at a predetermined distance to an inner surface of the U-shaped recess. Thus, the spacer is preferably dimensioned so that the PTC heating element is applied with the interposition of the insulating layer against the inner surface of the U-shaped recess, whereas on the opposite side of the sliding plate the package of PTC heating element and adjacent thereto insulating layers bounded on the outside, and of the the side facing away from the PTC heating element of the spacer and abuts against the other inner surface of the U-shaped recess. Preferably, a plurality of spacers are provided. The spacers can be formed for example by spring elements, which can be provided one above the other in the insertion direction of the PTC element in the U-shaped recess. Preferably, two spacers enclose between them a bearing or sliding surface for a wedge element, which clamps the PTC element in the U-shaped recess.

According to a preferred embodiment of the present invention, a sheet is provided, which surrounds the PTC element and the conductor tracks on one side, for example on the underside. This sheet metal element may be formed for example by the sliding plate. The sheet metal element may form a lower stop, by which the PTC heating element is predetermined in its end position in the U-shaped recess. The electrically insulating compound preferably completely or partially fills the space between the stop and the PTC element.

The sliding plate can be connected to the PTC element, for example glued. Usually, the sliding plate preferably forms a U-shaped receptacle for the PTC element together with the conductor tracks resting thereon and one each on the outside thereof limiting insulating layer. This prefabricated unit can be held by means of clamping in the U-shaped receptacle.

According to a preferred embodiment of the present invention, the conductor tracks project in the direction of insertion of the PTC element at least one side and are end, preferably on a side opposite the terminal lugs underside of the PTC element against a bar, the thickness of the thickness of the PTC element plus the thickness of the two tracks does not exceed. The conductor tracks are preferably formed in this preferred embodiment by contact plates, which have integrally formed by punching terminal lugs. The terminal lugs can pass through a further bar, which is provided opposite to the first, previously described bar and also connected to the conductor tracks. This upper bar usually has openings for the terminal lugs of the contact plates. To avoid an air gap and creepage distance between the PTC element projecting end portions of the conductor tracks, the electrically insulating mass is provided between these end portions and the bar. The other two faces, i. regularly the longitudinal side surfaces of the PTC element, ends here also preferably flat with the tracks. The strip may have a central projection, which forms contact surfaces for the contact plates.

According to the present invention, the mass is provided circumferentially around the PTC element and / or the track. The mass is preferably applied as an adhesive bead the PTC element and / or the conductor tracks sealingly around these components. Preferably, the insulating layer, particularly preferably both insulating layers, forms the edge of the PTC element over protruding edges. The electrically insulating mass is adhered as an adhesive mass on these edges. In this case, the electrically insulating compound preferably runs around the PTC element. Likewise, the edges of the insulating layer project beyond the PTC element on all sides. Between opposite insulating layers accordingly results in a circumferential bead of the electrically insulating material through which the PTC element is completely sealed. Only the terminal lugs pass through the insulating mass and are exposed on one connection side of the PTC heating element. The terminal lugs preferably project through a connecting flange for holding and positioning the PTC heating element in the U-shaped recess. This connection flange is over the adhesive electrically insulating Bonded to the PTC element. Thus, in this embodiment, preferably the PTC element and the interconnects thereon are covered and sealed in their entirety by the electrically insulating compound.

According to a further aspect, the present invention proposes an electric heating device, in particular for a motor vehicle, with heat-emitting surfaces which receive at least one PTC heating element between them. This PTC element is preferably formed according to one of the previously discussed embodiments.

With its secondary aspect, the present invention further proposes a method for manufacturing an electric heating device with the features of claim 13. In this method, the tracks are bonded to the PTC element to produce a PTC heating cell. The thus prepared PTC heating cell is placed between two electrical insulating layers and sealed by an electrically insulating material. In this case, the electrically insulating compound can first be placed on projecting edges of an insulating film forming insulating films. The PTC heating cell was previously placed on this film. Thus, the electrically insulating mass is applied around the PTC heating cell and on the one layer of the film. Thereafter, the insulating film is folded over to the sealing enclosure of the PTC heating cell and placed on the other of the conductor tracks. Thus, by surrounding the insulating film, a circumferential enclosure of the PTC heating cell by the electrically insulating mass. This then extends between the opposite inner surfaces of the insulating film and glued the two film sections preferably against each other. Excessive insulating compound can be forced out of the front side via the PTC heating element. The prepared in this way, externally insulating insulating PTC heating element can then be inserted into a U-shaped recess of a heater and electrically insulated by casting with the electrically insulating material herein, but are used with good thermal conductivity.

Figur 1

eine perspektive Seitenansicht eines ersten Aufführungsbeispiels eines PTC-Heizelementes;

Figur 2

eine perspektive Seitenansicht gemäß Figur 1 nach dem Umlegen der Hybridfolie;

Figur 3

eine perspektive Seitenansicht eines zweiten Aufführungsbeispiels eines PTC-Heizelementes;

Figur 4

eine perspektive Seitenansicht eines Aufführungsbeispiels eines Gleitbleches;

Figur 5

eine Querschnittsansicht einer Heizrippe eines nicht weiter dargestellten Ausführungsbeispiels einer elektrischen Heizvorrichtung nach dem Einsetzen eines vierten Aufführungsbeispiels eines PTC-Heizelementes gemäß Figur 1, 2 zusammen mit dem Gleitbleches nach Figur 4;

Figur 6

eine perspektivische, teilweise geschnittene Darstellung eines nicht weiter dargestellten Ausführungsbeispiels einer elektrischen Heizvorrichtung nach dem Einsetzen eines vierten Aufführungsbeispiels eines PTC-Heizelementes gemäß Figur 9;

Figur 7

eine perspektive Seitenansicht eines dritten Aufführungsbeispiels eines PTC-Heizelementes;

Figur 8

das in Figur 7 gezeigte Ausführungsbeispiel bei teilwiese weggenommener Masse und

Figur 9

eine perspektive Seitenansicht eines vierten Aufführungsbeispiels eines PTC-Heizelementes.

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 perspective side view of a first performance example of a PTC heating element;

FIG. 2

a perspective side view according to FIG. 1 after transferring the hybrid film;

FIG. 3

a perspective side view of a second performance example of a PTC heating element;

FIG. 4

a perspective side view of a performance example of a sliding plate;

FIG. 5

a cross-sectional view of a Heizrippe a not further illustrated embodiment of an electric heater after the insertion of a fourth performance example of a PTC heating element according to FIG. 1 . 2 along with the sliding plate after FIG. 4 ;

FIG. 6

a perspective, partially sectioned view of an embodiment of an electric heating device not shown after the insertion of a fourth performance example of a PTC heating element according to FIG. 9 ;

FIG. 7

a perspective side view of a third performance example of a PTC heating element;

FIG. 8

this in FIG. 7 shown embodiment in teilwiese weggenommener mass and

FIG. 9

a perspective side view of a fourth performance example of a PTC heating element.

The FIG. 1 shows a perspective side view of a PTC heating element 2 with a PTC element 4, which is arranged between two formed as contact plates made of sheet metal conductor tracks 6. In FIG. 1 only the upper one of the two contact plates 6 is shown. The PTC element 4 is located below. The PTC element 4 and the two contact plates 6 basically have the same footprint. The contact plates 6 are only upper side for forming a contact lug formed integrally on the sheet metal element 6.1. extended over the PTC element 4. The contact plate for forming a PTC heating element connected to the PTC element 4 via an adhesive, preferably an electrically conductive adhesive. This prefabricated PTC heating cell 7 is on a hybrid foil 8, which is wider than the PTC heating element 2. The hybrid film 8 consists of a relatively thin film on which an electrically non-conductive pasty mass is applied.

On the in FIG. 1 shown web of the hybrid film 8, the PTC heating element 2 is launched. Since the insulating layer formed by the hybrid film 8 slightly projects beyond the PTC element in the width direction, the hybrid film 8 forms in the width direction respectively protruding edges 8.1. The hybrid film 8 also towers over the PTC heating element 2 quite considerably on its underside and to some extent on the upper side, ie where the influencing vanes 6.1 protrude. This results in the PTC heating element 2 circumferential edges 8.1. On these edges 8.1. For example, the electrically insulating, but thermally conductive compound 10 which is also used to produce the hybrid film 8 is applied as a bead. The electrically insulating material 10 thus places itself against the exposed end edges of the two contact plates 6, which take the PTC element 2 between them. The bead of insulating mass 10 is applied with a sufficient volume, so that the height of the bead in about 1/2 to 4/5 of the height of the PTC element 4 plus the height of one of the two contact plates 6 corresponds.

Thereafter, the hybrid film 8 is turned over and on the in FIG. 1 still exposed top of the upper contact plate 4 is applied. Thereafter, the adhesive bead formed from the mass 10 contacts the hybrid film 8 and completely seals the PTC element 4 and / or one of the contact plates 6. Only the terminal lugs 6.1 enforce this circumferential electrically insulating enclosure of the PTC element.

Fig. 2 shows the embodiment according to Fig. 1 As can be seen, the hybrid film 8 projects beyond the bead 10 from the mass 10 on all sides. In addition, on the underside of the PTC heating element 2 opposite the connection lugs 6, there is a resultant of the envelope of the hybrid film 8 Receiving portion 11 which is formed continuously in the width direction of the PTC heating element 2.

The FIG. 3 shows an alternative embodiment. Like components are identified with respect to the embodiment described above with the same reference numerals.

The PTC heating element 2 after FIG. 3 has two insulating layers 12 extending parallel to each other. These insulating layers 12 may be layers of the aforementioned hybrid film. Alternatively, insulating layers of a ceramic and / or of a ceramic film coated with a plastic film may be provided. In this embodiment as well, the mass 10 is provided in the manner of a circumferential bead of adhesive so that at least one of the tracks 6 is completely surrounded by the mass 10 and the PTC element 4 completely, but not over its entire height, but only up to a height of about 1/2 of the thickness of the PTC element 4 is sealed.

The FIG. 4 shows a perspective side view of an embodiment of a sliding plate 14, which is by bending twice to a U-shaped profile in the side view arc. A thus formed U-shaped receptacle 16 is dimensioned such that the previously with reference to the FIGS. 1 to 3 discussed embodiments of PTC heating elements respectively in the U-shaped receptacle 16 fit. On an outer surface of the sliding plate 16 forms a sliding surface 18, which is surmounted on both sides by spacers 20, which are formed by bending of the sliding plate 14 forming material. The spacers 20 extend in the longitudinal direction of the sliding plate 14, and they are provided only in the upper portion of the sliding plate 14. In the extension of these spacers 20 oblique surfaces 22 are provided, which taper in a funnel shape on the sliding surface 18 and slightly surmount this sliding surface 18. The spacers 20 and the inclined surfaces 22 form a lateral boundary of an in FIG. 5 designated by reference numeral 24 wedge element.

The Figures 5 and 6 illustrate the installation situation of a received in the U-shaped receptacle 16 of the sliding plate 14 PTC heating element 2. Reference numeral 26, a part of a housing top is characterized, which can be placed on a trough-shaped and unillustrated housing lower part to a circulation chamber for liquid medium to be heated train as this from the EP 1 872 986 A1 is known. The disclosure of this document is - as far as the heater itself as such and in particular the details of the lower housing part and the upper housing part, incorporated by this reference in the disclosure of the present application.

The upper housing part 26 has a partition wall 28, which usually extends parallel to the bottom of the housing lower part, and usually has a plurality of heating ribs 30 projecting at right angles from this partition wall 28 and extending over a U-shaped recess 32 opens to a connection side of a heater for liquid media (in particular water heater).

In the U-shaped recess, the pre-assembled by inserting into the U-shaped receptacle 16 of the sliding plate 14 unit of PTC heating element 2 and sliding plate 14 is used, so deep until the end of the U-shaped arc-around sliding plate 14 on a Bottom 34 of the U-shaped recess 32 is seated.

How out FIG. 6 can be seen, the U-shaped recess 32 has lateral guide grooves 36 which extend in the insertion direction and the U-shaped recess 32 increases edge and in the thickness direction. These guide grooves 36 form receptacles for the spacers 20, in which the sliding plate 14 is guided and positioned during insertion of the sliding plate 14 with the PTC heating element 2. The spacers 20 press by abutment against the inner walls of the U-shaped recess 32, a wedge member receiving opening 38 free, in which after the complete introduction of the sliding plate 14 with the PTC heating element 2, the wedge element 24 is introduced. The wedge element 24 is provided with organic binder at least on one side, preferably on opposite main side surfaces, with a water-based PTFE lubricating varnish. Alternatively or additionally, such a bonded coating may be provided on a bearing surface formed by the U-shaped recess 32 for the wedge element 24 and / or the sliding surface 18. Such a coating serves as a dry lubrication during the insertion movement of the wedge element 24. The sliding-reducing coating ensures reproducible assembly results since surface roughnesses and the like which can vary within the production of the individual components are compensated by the coating. Thus, substantially the same insertion forces are necessary to apply different PTC heating element 2 with a predetermined surface pressure against opposing inner surfaces of one of the U-shaped recesses 32. This compression serves on the one hand the good dissipation of heat from the PTC element 4 in the inner surfaces of the U-shaped recess and on the other hand, the power input from the contact surfaces of the PTC heating element 2 in the PTC element 4th

Like the totality of FIGS. 1 to 6 can be seen, protrude beyond the insulating layers, which may be formed by the hybrid film 8 or the insulating layers 12, on the outside of the conductor tracks 6, the sliding plate 14 in the width direction and extend beyond Sliding plate 14 also in the height direction in the direction of the terminal lugs 6.1. The insulating layers project beyond at least that region in which the sliding plate 14 bears directly against the insulating layers (cf. FIG. 6 ). As a result, the air and creepage distance between the conductor tracks and the upper housing part 26 and thus the electrical safety of the heater is increased. In addition, the bead of the insulating compound 10 is also above the PTC element 4 and accordingly between the terminal lugs 6.1 different polarity. This also increases the creepage distance. In fact, at least one of the tracks 6 is completely enveloped by the mass 10, so that a considerable security against leakage current is given. The other of the two tracks 6 may be circumferentially exposed.

According to the third embodiment FIG. 7 are

Tracks 6 formed by metal sheets. The metal sheets, as described above by punching cut-free connection lugs 6.1 for the electrical connection of the contact plates 6. As the submitted for further clarification of this embodiment FIG. 8 can be seen, in which the longitudinal crawlers of the mass 10 are taken away for reasons of improved visibility of the details, the contact plates 6 each flush with the PTC element 4. In a direction perpendicular thereto, ie in the joining direction, the contact plates 6 extend beyond the PTC Element 4 on both sides. They are each on a bar 39 and 40 at. The two strips 39, 40 have a thickness which corresponds to the thickness of the PTC heating element 2 plus the two thicknesses of the contact plates 6. Thus, a flat outer surface is formed on the outside by the side surfaces of the strips 39, 40 on the one hand and the outer surfaces of the contact plates 6 on the other.

The strips 39, 40 each have inwardly excellent contact webs 42, each forming contact surfaces for the contact plates 6. The strips 39, 40 are provided at a distance from the opposite end face of the PTC element 4. In other words, a free space remains between a free front end face of the respective contact web 42 and the end face of the PTC element 4.

As the FIGS. 7 and 8th clarify, the PTC element is completely sealed by the bead of the insulating mass 10 in this embodiment, too. As in the previously discussed embodiment, the mass 10 does not have to extend over the entire thickness of the PTC element 4 for this purpose.

On the long sides is the caterpillar of mass 10 on the in FIG. 7 already shown hybrid foil 8 on and covers the in Fig. 7 lower conductor 6 almost completely frontally and part of the PTC element 4 frontally. The PTC element 4 is completely surrounded by the mass 10. At opposite end faces, ie adjacent to the strips 39, 40, the mass 10 serves not only to increase the creepage distance and air gap on the front side of the PTC element 4, but then as an adhesive, the strips 39, 40 with the connects to ordered track 6. The in FIG. 8 shown bead 10.1, 10.2 of electrically insulating material 10 bridges the gap between the contact bar 42 and the opposite end face of the PTC element 4. As a result, the creepage distance and creepage distance is routed between the tracks 6 of different polarity.

It goes without saying that the in FIG. 7 shown on the long side bead 10.3 of the mass 10 extend over the entire longitudinal extent of the conductor 4 and this can therefore cover completely on the longitudinal side.

An essential aspect of the present invention is also the FIG. 8 can be seen, after which the mass 10 is applied to a protruding edge of the insulating layer (in this case the hybrid film 8) to cover one of the conductor tracks 6 and the PTC element 4 to increase the creepage distance and creepage.

The Figures 5 and 9 can be seen in synonymous view another modified embodiment of a PTC heating element 2. In this PTC heating element 2, the upper bar 40 is L-shaped, so that relatively large-area plant leg results for the investment of the insulating layer 12. As in the previously discussed embodiment of the FIGS. 7 and 8th has the upper bar 40 recesses, which are designed adapted to carry out the terminal lugs 6.1. The design of the in FIG. 9 installed sliding plate 14 corresponds to the embodiment of the FIGS. 4 and 6 , Thus, the sliding plate 14 surrounds the lower bar 39. The lower bar 39 is located on the inside of a transverse web of the U-shaped receptacle 16 of the sliding plate 14 (see. FIG. 5 ). In the present case, the lower power 39 projects beyond the insulating layer 12 in the width direction, as does the sliding plate 14, partially surrounds the longitudinal bead 10.3 and forms a stop for relative positioning of adjacent PTC heating elements 2 in an elongated U-shaped recess of a heating rib. The lower bar 39 may be a plastic injection molded part.

One or both strips 39, 40 may be connected by encapsulation with the contact plates 6, including a contact plate at the level of a corresponding bar may have holes into which the strip forming plastic can enter molten to positively connect the strip with the contact plate. The other contact plate is glued regularly against the other bar. In this case, the mass 10 can also be used to fill a free space between the bar and the PCT element 4 and / or to connect the bar 39 to the PTC element 4.

The lower strip 39 usually has slightly rounded outer edges, in particular if the hybrid film 8 is to be beaten at the end around the strip 39. The rounded edges reduce the risk of damaging the hybrid film 8 during assembly.

LIST OF REFERENCE NUMBERS

2

PTC heating element

4

PTC element

6

Interconnect / contact plate

6.1

terminal lug

7

PTC heating cell

8th

hybrid film

8.1

edge

10

Dimensions

10.1

upper bead

10.2

lower bead

10.3

longitudinal bead

11

reception area

12

insulating

14

sliding

16

U-shaped receptacle

18

sliding surface

20

spacer

22

sloping surface

24

key member

26

Housing top

28

partition wall

30

heating ridge

32

U-shaped recess

34

ground

36

guide groove

38

Key member receiving opening

39

strip

40

strip

Claims (15)

PTC heating element (2) with at least one PTC element (4), which is provided between conductor tracks (6),
marked by
a at least one of the conductor tracks (6) and / or the PTC element (4) completely sealed insulating mass (10). PTC heating element (2) according to claim 1, characterized by an insulating layer (8, 12) projecting on the outside of the conductor track (6) and having the conductor track (6) and / or the PCT element (4) providing the insulating compound (10 ) specifies receiving area. PTC heating element (2) according to claim 1 or 2, characterized in that the insulating compound (10) is applied as the conductor track and / or the contact sheet circumferentially sealed adhesive bead. PTC heating element (2) according to one of the preceding claims, characterized in that the insulating mass (10) in the thickness direction partially surrounds the PTC element (4) and one of the conductor tracks (6). PTC heating element (2) according to one of the preceding claims, characterized by a to the insulating layer (8, 16) fitting sliding plate (14). PTC heating element (2) according to one of the preceding claims, characterized in that the insulating layer (8, 12) and / or the sliding plate (14) the PTC element (4) and the conductor track (6) project beyond the edge and that the insulating Mass (10) sealed at the edge of the conductor track (6) and / or the PTC element (4). PTC heating element (2) according to any one of the preceding claims, characterized in that the sliding plate has at least one spacer (20) formed by stamping and bending of a sheet metal forming the sliding plate (14), through which the PTC heating element (4) to a predetermined distance an inner surface of a U-shaped recess of an electric heater is durable. PTC heating element (2) according to one of the preceding claims, characterized in that the conductor tracks (6) project beyond the PTC element (4) and bear against the end against at least one strip (39, 40) whose thickness is the thickness of the PTC element. Element (4) plus the thickness of the two interconnects (6) does not exceed. PTC heating element (2) according to claim 8, characterized in that the strip (40) with the PTC element (4) by an insulating mass (10) is adhesively bonded, which is formed as an adhesive insulating mass and at least one of the conductor tracks ( 6) and / or the PTC element (4) sealed at the end. PTC heating element (2) according to one of the preceding claims, characterized in that the insulating mass (10) is formed as an adhesive insulating mass and is applied to an insulating layer (8), preferably around the PTC element (4) is applied circumferentially in that the insulating layer (8) covers at least one outer surface of the printed conductors (6) remote from the PTC element (4). Electric heating device, in particular for a motor vehicle with heat-emitting surfaces, which receive between them at least one PTC heating element (2), with a PTC element (4), which is contacted on both sides with conductor tracks (6) which are connected to the electrical connection of the PTC element. Element (4) are used and of which at least one on its the PTC element (4) facing away from the outer surface with an insulating layer (8, 12) is provided, characterized by at least one conductor track (6) and / or the PTC element (4 ) end-sealing insulating mass (10). Electric heating device according to claim 11, characterized in that the heat-emitting surfaces by opposite inner surfaces of a U-shaped recess (32) of a heater housing are formed, and that between the inner surfaces of the U-shaped recess (32) and an end face of the PTC heating element (2) only an electrically insulating mass (10) is provided. Method for producing an electrical heating device with at least one PTC element (4), which is provided between strip conductors (6), in which the strip conductors (6) are adhesively bonded to the PTC element (4) to produce a PTC heating cell (7) and at least one of the conductor tracks (6) and / or the PTC element (4) are completely sealed by an electrically insulating material (10). A method according to claim 13, characterized in that the PTC heating cell (7) with one of the conductor tracks (6) is placed on an insulating film (8), the insulating mass applied to protruding edges (8.1) of the insulating film (8) and the insulating film (8) is hammered into the sealing enclosure of the PTC heating cell (7) and placed on the other of the conductor tracks (6). A method according to claim 13 or 14, characterized in that the insulating mass (10) is applied as circumferential adhesive bead circumferentially against the conductor track (6) and at least partially against the PTC element (4).

Images