EP3863373B1 - Electric heating device and method for its production - Google Patents

Description

The present invention relates to an electric heating device with a housing with a partition wall that divides a connection chamber from a heating chamber for dissipating heat. At least one receiving pocket protrudes from the partition wall and projects into the heating chamber as a heating rib. A PTC heating device is provided in this pocket. Furthermore, a pressure element is accommodated in the pocket, which holds heat extraction surfaces of the PTC element against opposite inner surfaces of the receiving pocket.

The PTC heating device has at least one PTC element and conductor tracks that are electrically conductive to it. The conductor tracks are electrically connected to the PTC element. This connection can be a form-fitting and/or force-fitting and/or material-fitting connection.

The above-mentioned general characteristics of the electric heating device are considered to be state of the art according to EP 1 872 986 A1 They also apply to the realisation of the invention.

The applicant’s previous proposals EP 2 637 474 A1 or. EP 2 337 425 A1 each disclose PTC heating devices which are incorporated into a previously mentioned receiving pocket.

The EP 2 337 425 A1 a solution in which a conductor track lying on a main side surface of the PTC element is provided as a piece of sheet metal with contact projections bent out of the plane of the piece of sheet metal. The contact projections only serve to improve the electrical contact of the PTC element.

In the previously described known solutions, the receiving pocket tapers towards its lower closed end. Accordingly, the insertion opening that opens to the connection chamber is wider than the lower closed end of the receiving pocket. The PTC elements and the contact plates on both sides are usually clamped in the receiving pocket with at least one insulating layer between the conductor tracks and opposing inner surfaces of the receiving pocket using a wedge-shaped pressure element, as for example in EP 3 101 365 A1 This wedge element ensures that the layers of the layer structure are clamped against each other in the receiving pocket. These layers are at least the PTC elements and are perpendicular to the direction of force of the wedge element, usually contact plates, and at least one insulating layer.

Despite the cross-sectional shape of the receiving pocket, which is tapered downwards due to manufacturing technology, the wedge element should enable good heat transfer, preferably between the two opposing heat extraction surfaces of the PTC element and the inner surfaces of the receiving pocket assigned to them, with the pressure element in between. The pressure built up there also causes the opposite heat extraction surface of the PTC element to be placed directly or with an insulating layer in between against the opposite inner surface of the receiving pocket.

CN109028554A discloses an electric heating device with the preamble features of claim 1. In this prior art, the PTC heating device comprises a pocket-shaped heater housing which has opposite side sections which are connected to one another via a base section and which accommodates the PTC element and the conductor tracks. The pocket-shaped heater housing accordingly forms a receptacle at least for the PTC heating element. The pocket-shaped heater housing is wedge-shaped in cross section in order to enable uniform heat-conducting contact of the heater housing designed as a pressure element with the inner surfaces of a receiving pocket which tapers towards its lower end facing away from the connection chamber.

The previously presented solutions from the state of the art each ensure good heat extraction. However, there is the problem that the receiving pocket does not always correspond to the designed shape due to manufacturing tolerances. This is because the PTC elements are subject to considerable dimensional fluctuations due to manufacturing. It is also not always guaranteed that the heat extraction surfaces of the PTC element are completely straight and flat.

Pressing in a wedge as a pressure element can lead to stress peaks, which can cause the ceramic PTC element or a ceramic insulating layer inside the receiving pocket to break. Depending on the tolerances, the wedge element used as a pressure element in the state of the art may not be thick enough in the specific application, so that it basically sits ineffectively on the lower end of the receiving pocket. If, however, the free space remaining before the wedge element is inserted is too small, this results in a tension peak in the height direction of the receiving pocket, ie between the lower end and the The insertion opening does not adequately cover the heat extraction surface of the PTC element. As a result, the PTC element heats up too much and prevents further power consumption. The efficiency of the PTC element is therefore poor.

It is also possible that layers of the PTC heating device and/or the pressure element or the PTC heating device as a whole are pushed out of the receiving pocket or migrate out due to vibrations.

The present invention aims to at least partially remedy the aforementioned problems.

For this purpose, the present invention proposes an electric heating device with the features of claim 1.

In the heating device according to the invention, the receiving pocket protrudes into the heating chamber in a manner known per se as a heating rib. The receiving pocket is usually formed as one piece on the partition wall. The receiving pocket is usually made of a material that conducts heat well, usually metal. The receiving pocket on its own or in conjunction with the partition wall can be made by deep drawing or casting a metal. The receiving pocket is preferably made of aluminum and is formed as one piece on the partition wall by forming, in particular by deep drawing.

The receiving pocket has - like the receiving pocket known from the prior art - preferably a wedge-shaped cross-sectional shape which tapers towards the bottom of the receiving pocket, i.e. the end of the heating fin protruding into the heating chamber.

According to the invention, the heater housing is accommodated in this receiving pocket. The heater housing usually accommodates the PTC element completely and at least the conductor tracks predominantly. In particular, the main side surfaces of the PTC element are usually covered by the heater housing. When assembled, the heat-dissipating main side surfaces of the PTC element are arranged opposite the side surfaces of the heating fin, so that heat can be coupled out of the PTC element in a direction transverse to the main side surfaces, conducted through the receiving pocket and discharged to the heating chamber via the side surfaces. The heater housing is located in this heat conduction path.

The heater housing is usually made of a material that conducts heat well. The heater housing is in particular made of a flowable material, for example Copper or aluminum, which has a relatively low strength but good thermal conductivity. The heater housing can also be made of a plastic that is highly filled with thermally conductive particles. The volumetric filling level of the thermally conductive particles should not be less than 60 percent by volume.

The heater housing not only houses the PTC element and mainly the conductor tracks. There is usually also at least one insulating layer between the PTC element and an inner surface of the heater housing, which can be made of an electrically insulating material, in particular a plastic or a ceramic. The insulating layer usually covers the conductor track that is directly electrically conductive to the PTC element on the outside, so that this polarity does not directly contact the inner surface of the heater housing.

On the opposite side, the current can be introduced directly through the heater housing, which in this case forms the conductor track. Usually, however, two conductor tracks, which are assigned to different polarities, are accommodated as separate components in the heater housing and are each electrically insulated from the heater housing by an insulating layer. The insulating layers provided parallel to the opposite main side surfaces of the PTC element can be made of a single film wrapped around the underside of the PTC element. The PTC element can be accommodated in a positioning frame made of an electrically insulating material which positions the PTC element(s) and spaces them apart from one another, so that the positioning of the positioning frame in the heater housing achieves a predetermined alignment and arrangement of the PTC element(s) in the receiving pocket. This positioning frame can be covered with the insulating layers on the outside or surrounded by a single insulating layer.

According to the present invention, the heater housing is pressed into the receiving pocket with plastic deformation of the heater housing and/or the receiving pocket. The heater housing and/or the receiving pocket can have opposing main sides or inner surfaces that are inclined to one another at an angle of between 2° and 5°.

During assembly, the heater housing is usually first fitted with the elements accommodated therein, ie the PTC element of at least one conductor track and the insulation layer provided if applicable. The heater housing is then placed in the receiving pocket. Plastic deformation then takes place. For example, the heating fin can be plastically deformed by placing a deformation tool directly interacts with the heating rib. In addition or as an alternative, a deformation tool can also act against the heater housing in order to bring about the plastic deformation according to the invention from the inside of the receiving pocket. In any case, due to the deformation, an intimate plastically deformed connection is achieved between the heater housing and the inner surface of the receiving pocket. Furthermore, due to the deformation of the heater housing and/or receiving pocket, the PTC element is arranged firmly, in particular vibration-resistant and with good heat conduction in the heat path between the PTC element and the side surface of the heating rib.

In the previously described designs, in addition to a vibration-proof fastening of the PTC element in the receiving pocket, there is good heat extraction and a usually complete or at least almost complete filling of the receiving pocket by the components placed therein, at least in the area of the receiving pocket that is of particular importance for the heat extraction from the PTC element. The lower area of the receiving pocket is usually connected to the heater housing over its entire surface. There is also full-surface contact between the main side surfaces of the PTC element and the associated inner surfaces of the receiving pocket, and thus good heat extraction from the PTC element to the side surfaces of the heating fin. In the heat conduction discussed here, the heat conduction path from the main side surfaces to the side surfaces of the heating fin is particularly important. Due to their smaller dimensions, the front side surfaces of the PTC element can usually only make a smaller contribution to the heat extraction anyway. The main side surfaces are usually the surfaces that have the greatest extension in the length or width direction of the PTC element. The end faces connect these main side faces. The PTC element is usually cuboid-shaped and has a much larger extension in the length or width direction than in the height or thickness direction. The thickness direction is usually at least a factor of 5 smaller than one of the dimensions in the length and/or width direction. The main side face is spanned by the two extensions in the length and width.

According to a preferred development of the present invention, the heater housing is connected to the receiving pocket in a material-locking manner, particularly as a result of the plastic deformation, particularly preferably cold-welded. In this preferred development, the plastic deformation of the heater housing and/or receiving pocket must take place in such a way that a material-locking connection, in particular formed by welding, is produced between the heater housing and the receiving pocket.

A front surface extending essentially transversely in the direction in which the PTC element is inserted can be provided adjacent to the bottom of the receiving pocket. Usually, at least after plastic deformation, material from the heater housing is also located between the bottom of the receiving pocket and this front surface. The opposite front surface extending parallel to this is adjacent to the connection chamber and can usually contribute little to heat extraction. The front surfaces of the PTC element extending at right angles to these two front surfaces can be exposed in the receiving pocket without an immediate heat conducting surface. This is preferable for reasons of good electrical insulation. In this case, after the heater housing has been inserted and deformed, the receiving pocket is usually filled with an electrically insulating mass which prevents air and leakage currents and which can be located between a front boundary of the heating fin and the corresponding front surfaces of the PTC element, so that a certain amount of heat extraction to the outer surface of the heating fin can also take place via this electrically insulating mass. The mass with good thermal conductivity can be, for example, a hardening silicone mass to which electrically non-conductive but good thermal conductivity particles have been mixed. These particles can be aluminum oxide balls.

The following consideration relates in particular to a cross-sectional view through the PTC element, which intersects the upper and lower end faces and extends parallel to the edge end faces of the PTC element. In such a cross-sectional view, at least one surface of the heater housing that rests against the receiving pocket is convex. This shape of the heater housing can refer to the state before deformation. However, such a convex design usually also results in a deformed design in which the heater housing rests against the inner surface of the receiving pocket with a convex surface. In this case, the inner pocket can have been deformed concavely outwards as a result of a deformation of the heater housing, corresponding to the convex design of the heater housing.

According to a preferred development of the present invention, at least one fixing lip is formed on the heater housing by an undercut. This fixing lip is plastically deformed at least in sections by pressing the heater housing into the receiving pocket and is placed against the inside of the receiving pocket. This development is based on the idea that a slightly deforming fixing lip forms a type of barb or the like, which at least after the plastic deformation improves anchoring of the heater housing in the The fixing lip can be provided at any point in the vertical direction, ie the direction in which the heater housing is inserted into the receiving pocket. With a view to achieving the best possible heat extraction between the main side surfaces and the heating fin, it is preferable to provide the corresponding fixing lip close to the bottom of the receiving pocket.

In view of this, the present invention proposes providing the heater housing with two legs and a heater housing base connected to them. The heater housing forms a substantially U- or V-shaped receiving space for the PTC element and the at least one conductor track, the inner walls of which can be aligned parallel to one another. The said fixing lip is provided on at least one, preferably two legs, with the at least one fixing lip being provided in the area of the heater housing base. The base is by definition the area that lies in front of the PTC element in the direction in which the heater housing is inserted into the receiving pocket.

According to a preferred development of the present invention, the heater housing has a contact surface adapted for the attachment of a pressing tool at a rear end in the pressing direction. This contact surface can be formed by a substantially flat surface extending transversely to the pressing direction. The contact surface can also be formed by a trough-shaped depression. The contact surface is adapted for the attachment of a pressing tool. This pressing tool usually acts on the heater housing from the connection chamber in order to press the heater housing in the receiving pocket, in particular to plastically deform it and thus to cold-weld it in the receiving pocket. This usually takes place when the heater housing is inserted into the receiving pocket.

According to a further development of the present invention, the heater housing can have at least one inwardly directed locking projection. In the finished product, this locking projection usually lies flat in the direction of the PTC element, for example against the insulating layer. The locking projection can act like a barb, which prevents the PTC element from being accidentally released from the heater housing, which may be open at the top. After the plastic deformation of the heater housing, this locking projection can basically be integrated into a flat contact surface that extends parallel to a main side surface of the PTC element and forms, for example, a contact surface for the insulating layer.

The aforementioned heater housing can be manufactured as an elongated material by means of pultrusion or extrusion and subsequently cut to length so that its length essentially corresponds to the width of the PTC element.

The present invention also provides a method for producing an electric heating device of the type mentioned above. In the method, the PTC element with the at least one conductor track, optionally with the aforementioned insulating layer, is introduced into a heater housing and into the receiving pocket. The heater housing can first be equipped with the elements contained therein and then introduced into the receiving pocket. Alternatively, the heater housing can also first be introduced into the receiving pocket and then equipped.

In any case, according to the method according to the invention, during the introduction of the heater housing or after the introduction of the heater housing and the components received therein, the heater housing is pressed into the receiving pocket under plastic deformation and is preferably cold-welded to the receiving pocket.

Preferably, in the case of the invention, when the heater housing is introduced into the receiving pocket, preferably after the heater housing has been equipped with the components, a heater housing base in the base of the receiving pocket is plastically deformed.

According to a preferred development of the present invention, in which the heater housing is first fitted with the aforementioned components and then inserted into the receiving pocket, the heater housing is gripped by an insertion tool for insertion. In this case, opposing legs of the heater housing are usually gripped by the insertion tool and pivoted towards each other. The heater housing is placed against the PTC element by the insertion tool under elastic and/or plastic deformation before being inserted into the receiving pocket. The installation can take place directly against the PTC element or with an insulating layer or the contact plate in between. Usually, the previously mentioned, inward-facing locking projection of the heater housing is plastically deformed in this methodical procedure, so that a flat counter surface is formed for the PTC element on both main sides of the same on the side of the heater housing, against which the PTC element rests directly or indirectly with the contact plate and/or the insulating layer in between.

Fig. 1

eine perspektivische Seitenansicht eines Ausführungsbeispiels einer elektrischen Heizvorrichtung mit teilweise weggenommenem Gehäuse;

Fig. 2

eine Querschnittsansicht der in Figur 1 mit Bezugszeichen 102 gekennzeichneten Gehäusebasis mit einer ersten Variante eines Heizergehäuses, das in einer Aufnahmetasche eingepresst ist

Fig. 3

eine perspektivische Schnittansicht der Aufnahmetasche mit einer zweiten Variante eines Heizergehäuses vor dem vollständigen Einbringen in die Aufnahmetasche;

Fig. 4

eine perspektivische Schnittansicht der Aufnahmetasche mit einer dritten Variante eines Heizergehäuses vor dem vollständigen Einbringen in die Aufnahmetasche;

Fig. 5

eine perspektivische Schnittansicht der Aufnahmetasche mit einer vierten Variante eines Heizergehäuses vor dem vollständigen Einbringen in die Aufnahmetasche;

Fig. 6

eine perspektivische Schnittansicht der Aufnahmetasche mit einer fünften Variante eines Heizergehäuses vor dem vollständigen Einbringen in die Aufnahmetasche und

Fig. 7

das Ausführungsbeispiel nach Figur 6 in einer Seitenansicht mit vollständiger Heizrippe.

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

Fig.1

a perspective side view of an embodiment of an electric heating device with the housing partially removed;

Fig.2

a cross-sectional view of the Figure 1 housing base marked with reference number 102 with a first variant of a heater housing which is pressed into a receiving pocket

Fig.3

a perspective sectional view of the receiving pocket with a second variant of a heater housing before it is completely inserted into the receiving pocket;

Fig.4

a perspective sectional view of the receiving pocket with a third variant of a heater housing before it is completely inserted into the receiving pocket;

Fig.5

a perspective sectional view of the receiving pocket with a fourth variant of a heater housing before it is completely inserted into the receiving pocket;

Fig.6

a perspective sectional view of the receiving pocket with a fifth variant of a heater housing before it is completely inserted into the receiving pocket and

Fig.7

the embodiment according to Figure 6 in a side view with complete heating fin.

The Figure 1 shows a housing 100 of an electric heating device, which comprises a bottom element 102, a housing base 104 and a housing cover 106. In the exemplary embodiment shown, the housing base 104 forms a partition wall 108 extending parallel to the housing bottom 102, which separates a circulation or heating chamber 110 from a connection chamber 112. In the exemplary embodiment shown, at least the housing base 104 is made in one piece from aluminum. Heating fins 114 protrude from the partition wall 108 in the direction of the heating chamber 110. These heating fins are tapered towards their fine end at an angle of approximately 2.5° and form a receiving pocket 116 with opposing inner surfaces 118. The interior of the heating fin 114 and the connection chamber 112 is fluidically separated from the heating chamber 110.

In this case, connections lead to the heating chamber 110 on opposite end faces of the housing base 104. These connections are shaped as hose or pipe connection pieces 120 and protrude from the outside of the actual wall of the housing base 104. They are used to connect hoses or lines that lead to liquid fluid that is to be heated in the heating chamber 110.

For this purpose, the receiving pockets 116 are each equipped with PTC heating devices 2. One or more of these PTC heating devices 2 can be inserted one behind the other in the longitudinal direction of the heating fins 114 in the individual receiving pockets 116.

The essential structure of the PTC heating device 2 is basically identical for the variants discussed below. The PTC heating device 2 has a heater housing 4, which comprises opposite legs 6, which are pivotally connected to one another via a heater housing base 8. The heater housing 4 is open on the side opposite the heater housing base 8. It is usually surmounted by contact plates 10, which are electrically conductive and lie directly against a PTC element 12 and form one-piece connection lugs 14 formed by punching and bending a sheet metal material forming the contact plates 10 as contact tongues for the plug-in contact of the PTC heating device 2. These connection lugs 14 are in Figure 2 shown. In the remaining illustrations according to the Figures 3 ff. the detailing of the connection lugs was omitted.

As shown in the sectional view Figure 2 the PTC element 12 is located in a circumferentially enclosed receptacle of a positioning frame 16 made of insulating material, from which Figure 1 only the upper and lower frame members 18, 20 can be seen. The PTC element 12 usually projects beyond the frame members 18, 16 in the thickness direction, ie a thickness direction of the receiving pocket 116, so that the electrically conductive contact of the contact plates 10 on the PTC element 12 is not impaired by the positioning frame 16.

On the side opposite the PTC element 12, an insulating layer 22 rests on the outside of the contact plates 10. This insulating layer 22 is formed in one piece and wraps around the underside of the positioning frame 16.

The previously described elements of the PTC heating device 2 are accommodated in the heater housing 4, which in the present case is made of aluminum and is produced by extrusion and cut to length. The width of this heater housing 4 corresponds in the present case approximately the width of the PTC element 12. The width direction extends transversely to the display plane to Figure 2 . The other dimension of the PTC element 12 that can be seen here in addition to the thickness is the length. This extension corresponds approximately to the direction in which the PTC heating device 2 is inserted into the receiving pocket 116.

The Figure 2 The right leg 6 of the heater housing 4 is thicker than the left leg and has a contact surface 26 which extends essentially transversely to the direction of insertion and which is flat and continuous across the width of the heater housing 4. Above this contact surface 26, the right leg 6, like the left leg 6, is also designed as an essentially thin and flat plate.

The sectional view shows fixing lips 28 protruding from the base in the width direction, which protruded further in the transverse direction before the heater housing 4 was inserted into the receiving pocket 116 and were reshaped parallel to the inner surfaces 118 when inserted into the receiving pocket 16. These fixing lips 28 can act like barbs.

By applying a force to the contact surface 26, the heater housing 4 is plastically deformed in the receiving pocket 116. This plastic deformation can also permanently deform the heating rib 114. In any case, the plastic deformation results in cold welding. To do this, the contact surface 26 can be pressed with a pressing force of between 1400 and 3000 Newtons. This causes the aluminum material of the heater housing 4 to flow and bond firmly to the inner surfaces 118 of the receiving pocket 116.

Usually, the components of the PTC heating device which are accommodated within the heater housing 4, namely the PTC element 12 previously inserted into the receptacle of the positioning frame 16, the contact plates 10 adjacent thereto and the insulating layer 22 are introduced as a unit between the legs 6 of the heater housing 4 before the latter is introduced into the receiving pocket 116 and pressed therein.

The Figures 3 to 7 show variants of the heater housing 4. Otherwise, the same components as in the previous description are provided with the same reference symbols. In the illustrations according to the Figures 3 to 7 the heater housing 4 with the components accommodated therein is not yet fully inserted into the receiving pocket 116. Rather, it partially protrudes beyond the partition wall 108.

In the previously discussed embodiment, the heater housing 4 forms legs 6 with flat outer surfaces. These outer surfaces diverge, but are flat, i.e. even.

At the Figure 3 In the variant shown, the legs 6 are slightly convex. They have a radius of between 500 and 1000 mm. The fixing lips 28 are omitted in this embodiment. Instead of a positioning frame 16, only an electrically non-conductive plastic web 30 is provided between a base of the heating fin 114 and the PTC element 12. The contact surfaces 26 are formed on both sides of the PTC element 12 on the two legs 6. When the contact force is applied on both sides of the PTC element, the material forming the heater housing 4 flows and thus a more uniform connection between the heater housing and the inner surfaces 118 is created. In addition, the PTC element 12 can be arranged centrally to the receiving pocket 116 so that the same heat dissipation conditions prevail on both main side surfaces of the PTC element 12. The main side surface is the surface that extends in the longitudinal direction and in the width direction of the PTC element 12.

In the variant according to Figure 4 a plurality of fixing lips 28 are formed opposite the main side surfaces of the PTC element 12. These are limited to the upper area of the PTC element 12. Otherwise, the Figure 4 shown third variant of the second variant according to Figure 3 .

In the fourth variant after Figure 5 Fixing lips 28 are formed only in the area of the heater housing base 8. These fixing lips 28 deform, among other things, in the base of the receiving pocket 116. Here, too, two contact surfaces 26 are formed. The outer surfaces of the legs 6 are convex.

In the Figure 6 The variant shown combines the variant according to the Figures 4 and 5 .

The Figure 7 shows a view of the entire width of the receiving pocket 116 and the PTC heating device 12. At the front of the PTC heating device, a certain gap remains to the front boundary of the receiving pocket 116. After the PTC heating device 2 has been introduced into the receiving pocket 116, the remaining free space within the receiving pocket 116 can be filled with a mass that has good thermal conductivity and is usually electrically insulating.

Figure 7 illustrates an inwardly directed locking projection 32. This locking projection 32 is usually flat in the finished product in the direction of the PTC element 12, specifically against the insulating layer 22. The locking projection 32 can act like a barb, which prevents the PTC element 12 from being accidentally released from the heater housing 4. After the plastic deformation of the heater housing 4, this locking projection 32 is basically integrated into a flat contact surface, which extends parallel to a main side surface of the PTC element 12 and in this case forms a contact surface for the insulating layer 22.

List of reference symbols

2

PTC heating device

4

Heater housing

6

leg

8th

Heater housing base

10

Contact plate/conductor tracks

12

PTC element

14

Connection lug

16

Position frame

18

Upper frame beam

20

Lower frame member

22

Insulation layer

26

Contact surface

28

Fixation lip

30

Plastic bridge

32

Locking projection

100

Housing

102

Case back

104

Housing base

106

Housing cover

108

partition wall

110

Circulation chamber/heating chamber

112

Connection chamber

114

Heating fin

116

Recording pocket

118

Inner surface

120

Connection piece

Claims (12)

1. An electric heating device comprising:

   a housing (100) having a partition wall (108) separating a connection chamber (112) from a heating chamber (110) for emitting heat from which at least one receiving pocket (116) projects into the heating chamber (110) as a heating rib (114), in which a PTC heating means (2) having at least one PTC element (12) and conductive tracks (10) are accommodated which are electrically conducting connected to the PTC element (12) with different polarity for energizing the same and are electrically connected in the connection chamber (112), wherein the PTC element (12) and at least one of the conductive tracks (10) are accommodated in a heater housing (4),

   characterized in that

   the heater housing (4) is pressed into the receiving pocket (116) with plastic deformation of the heater housing (4) and/or the receiving pocket (116).
2. The electric heating device according to claim 1, characterized in that the heater housing (4) is connected to the receiving pocket (116) by a material bond and is preferably cold-welded thereto.
3. The electric heating device according to claims 1 or 2, characterized in that at least one surface of the heater housing (4) abutting against the receiving pocket (116) is formed to be convex.
4. The electric heating device according to any one of the preceding claims, characterized by at least one fixing lip (28) formed by an undercut on the heater housing (4), which is plastically deformed at least partially by pressing the heater housing (4) into the receiving pocket (116) and is delimited in the thickness direction by opposite inner surfaces (118), and is abutted against an inner surface (118) of the receiving pocket (116).
5. The electric heating device according to claim 4, characterized in that the heater housing (2) includes two legs (6) and a heater housing base (8) connecting the legs (6) to each other as a result of which a substantially U-shaped or V-shaped receiving space is formed for the PTC element (12) and the at least one conductive track (10), and in that at least one fixing lip (28) is provided on at least one of the legs (6) and/or two fixing lips (28) are provided formed on opposite sides of the heater housing base (8).
6. The electric heating device according to any one of the preceding claims, characterized in that the heater housing (4) includes, at a rear end in the pressing-in direction, an abutting surface (26) adapted for applying a pressing tool.
7. The electric heating device according to any one of the preceding claims, characterized in that the heater housing (4) has at least one inwardly facing locking projection (32).
8. The electric heating device according to any one of the preceding claims, characterized in that the heater housing is manufactured by a pultrusion or extrusion process.
9. A method for manufacturing an electric heating device comprising a housing having a partition wall separating a connection chamber from a heating chamber for emitting heat from which at least one receiving pocket projects into the heating chamber as a heating rib, in which a PTC heating means having at least one PTC element and conductive tracks are accommodated which are electrically conductively connected to the PTC element with different polarity for energizing the same and are electrically connected in the connection chamber, wherein in the method
   the PTC element (12) and at least one of the conductive tracks (10) is inserted into a heater housing (4) of the PTC heating device (2) and into the receiving pocket (116), and the heater housing (4) is pressed into the receiving pocket (116) with plastic deformation of the heater housing (4) and/or the receiving pocket (116) and is preferably cold-welded to the receiving pocket (116).
10. The method according to claim 9, characterized in that the heater housing (4) is inserted into the receiving pocket (116) in such a way that a heater housing base (8) is plastically deformed in the base of the receiving pocket (116).
11. The method according to claims 9 or 10, characterized in that the PTC element (12) and the at least one conductive track (10) are first inserted into the heater housing (4) and the heater housing (4) thus equipped is inserted into the receiving pocket (116).
12. The method according to claim 11, characterized in that the heater housing (4) is gripped for insertion by an insertion tool, by means of which the heater housing (4) is abutted against the PTC element (12) under elastic or plastic deformation before the heater housing (4) is inserted into the receiving pocket (116).

Images