EP2637475B9 - Heat generating element - Google Patents

Description

The present invention relates to a heat-generating element having at least one PTC element, on both sides thereof contact plates, a one-piece housing, which forms at least one opening for receiving the at least one PTC element and has a connection side, are exposed at the contact plates associated contact tongues , The heat generating element according to the invention preferably has a wedge element with a wider and a narrower end surface, which are connected to each other via first and second wedge surfaces, wherein the first wedge surface extends parallel to one of the contact plates and the second wedge surface is exposed on the outside of the housing.

The US 2008/314893 A1 discloses a multi-part housing which accommodates two contact plates, which enclose a PTC element between them and are formed with arcuate connecting straps which project beyond the housing on one connection side. This structure is structurally complex.

The EP 0 026 457 A2 discloses a heat generating element having a PTC element sandwiched between two ceramic plates provided with a metallically conductive coating on the inside thereof. The coating is contacted in each case with a terminal lug, which projects laterally beyond the layer structure. Around the layer structure and substantially between the ceramic plates, a frame made of an insulating material is injected. In injection molding of the frame, the terminal lugs are sealed in the insulating material. The electrically conductive coating on the inside of the ceramic plates is connected by soldering to the respective terminal lugs and the PTC element.

The EP 2 017 103 A1 discloses an electric heater having a plurality of heat-generating elements, which are accommodated as part of a layer structure alternately with corrugated fin layers in a heater housing. Each heat-generating element has a housing made of an insulating material with a plurality of openings provided in the longitudinal direction of the housing in succession, each receiving at least one PTC element in itself. On both sides of the PTC elements are contact plates, which are on a connection side of their plant level out and bent back to form a terminal lug which extends parallel to a formed by the contact plates contact surface for the PTC element. The contact sheets are formed by hot forming a holding web formed by the housing with the housing.

The US 3,940,591 A1 discloses a heat-generating element having a housing in which a PTC element is held between two contact sheets. The housing is formed of an insulating material and forms a receiving pocket for the PTC element and the associated contact plates. One of the contact plates has formed by bending molded spring arms, via which the layer structure consisting of the two contact plates is held with the interposed PTC element under bias in the insulating housing.

A generic heat generating element is known from EP 1 921 896 A1 known. In this prior art, the housing is formed by two housing elements which can be connected to each other and are each formed as a plastic injection molded parts. The contact sheet and on the outside respectively provided thereon insulating layers are thereby encapsulated with the housing element each forming plastic material to form a unit of contact sheet, insulating layer and housing element.

Such heat-generating elements are used in particular for heating liquids, especially in a motor vehicle. A typical multiple heat generating elements receiving electrical heater has one or more parallel to each other extending pockets. The pockets separate a circulation chamber for the fluid to be heated from a connection side, in which usually the electrical contacts are exposed and connected. Since the chambers are formed of a metallic and therefore electrically conductive material, a good electrical insulation between the heat-generating element inserted into the pocket and the walls bounding the pocket inside is of great importance for the reliability of the electrical heating device.

The generic heat generating elements are usually first inserted into the bag. Thereafter, the wedge member is displaced relative to the inner wall of the pocket and an outer surface of the heat generating element to key the heat generating element in the pocket. The wedge element lies with its first wedge surface parallel to one of the contact plates, usually with an intermediate layer an insulating layer, and with its second wedge surface usually parallel to a slightly tapered inner surface of the pocket. Accordingly, there is a planar contact between the heat generating element and the bag through the intermediary of the wedge element. On the one hand, the other contact plate, usually also with the interposition of an insulating layer, on the inner surface of the bag, on the other side with the interposition of the wedge element. For an effective use of the heat generating element, this arrangement is essential, since due to the self-regulating properties of the PTC elements for a good, symmetrical as possible and thus mutual heat dissipation is to ensure. Otherwise, the PTC element becomes too hot and the self-regulating properties of the PTC element prevent further absorption of electrical energy for heat generation.

In the generic heat-generating element, various problems arise. Thus, when moving the wedge element to be feared that move the layers of a layer structure within the heat generating element against each other. These layers include - from the inside to the outside - the PTC element, the contact plates on both sides, which are usually provided on the outside insulating layers, each individual contact plate also several different insulating layers may be assigned, and finally the wedge element itself. In the aforementioned The prior art, the contact plate is inserted only in the housing. It is supported on the foot side at one edge of the housing. Furthermore, there is the problem that on the one hand the contact sheet must be completely surrounded by an insulating layer, which insulating layer must also cover edge portions of Kontakbleches to safely prevent exposure of electrically conductive surfaces on the outside of the heat generating element. The over-molding of the contact sheet, which is known from the prior art, together with the insulating layer can lead to defects, in particular to the insulating layer, due to the thermal entry during injection molding and / or the injection pressures prevailing in the process. Even microscopic cracks justify the risk of high rejects, since they are not recognized correctly during production, so that faulty heat-generating elements are built into the electric heating device and render them altogether unusable.

The present invention seeks to provide a heat generating element which completely or partially avoids the problems described above.

To achieve the above object, the generic heat-generating element is further developed in that at least one of the contact plates has a bent tab, which is accommodated in an opening formed by the housing insertion.

The arched insertion tab extends substantially transversely to a contact surface formed by the contact plate and usually towers over this contact surface, i. goes inward toward the interior of the housing and extends in the thickness direction of the PTC element. Corresponding to this insertion tab, the housing has an insertion opening in which the insertion tab is received. The tuck is usually held with little play, preferably without play in the insertion. Due to the interaction of insertion tab and insertion opening, the contact plate is held in a direction parallel to its contact surface for the at least one PTC element substantially immovably on the housing. The contact plate is, however, connected by inserting the tuck into the insertion only after the manufacture of the housing with this. Accordingly, the housing of the heat-generating element can be made much easier. The housing is formed in one piece and may preferably be produced as a simple injection-molded part and be equipped later with the layers forming the layer structure.

In order to avoid a weakening of the housing as far as possible, it is proposed according to a preferred development of the present invention to form the tuck-in tab by a cut-in insertion lug. This Einsteckfahne has a much smaller width than the contact plate on the provided by the contact tab edge side of the contact plate. The design offers the further advantage that forces for inserting the Einsteckfahne can remain relatively small in the insertion, since the cooperating friction surfaces are kept relatively small, so that overall shows a relatively small frictional resistance during insertion of the tuck into the insertion.

This embodiment is particularly significant if, according to a preferred development of the present invention, at least one latching projection projects from a surface of the push-in tab which is oriented substantially at right angles to a contact surface for the PTC element, which is formed by the associated contact plate protrudes, which is locked to the housing. The locking projection should preferably be formed with respect to low insertion forces as a point locking cam and locked to the housing. A plurality of latching projections can be provided side by side on the surface aligned at right angles to the contact surface for the PTC element. The corresponding latching projection is preferably formed by punching machining of the contact sheet. He usually interacts with a locking shoulder, which is formed by the housing and which is formed thin-walled in view of the desired low Einbringkräfte for joining the housing and contact plate, while - as usual with latching connections - in the assembled state, the locking projection surmounted and thus the Hold the contact sheet on the housing in a form-fitting manner.

With this configuration, the contact plate can be prepared as a simple stamped and bent part and then joined to the housing in a simple manner. The contact plate preferably has a contact projection between the contact tongue and the contact surface for the at least one PTC element. The housing has a plant shoulder associated with the investment projection. In this preferred embodiment, the housing and the contact plate are dimensioned such that the push-in tab can be inserted into the insertion opening when the contact shoulder bears against the contact shoulder by pivoting about the contact shoulder. In this embodiment, the investment projection and the housing side associated Anlageschulter serve as an assembly aid.

Usually, the abutment shoulder is located in the region of a receptacle formed by the housing for the contact tongue, preferably a contact lug formed by the contact plate. The contact tongue does not necessarily have to be integrally formed on the contact plate. Such a design is, however, to be preferred. In any case, the contact plate is preferably surmounted on its side facing the tab from a stamped by punching contact lug, which can form the end of the contact tongue or is connected to this. In this case, the housing-side receptacle and the contact lug form a guide, which causes, as part of the insertion movement of the contact lug in the recording of the investment projection is necessarily applied against the abutment shoulder. This abutment of the investment projection against the abutment shoulder marks the end of the insertion movement for a fitter. Thereafter, the installer only has to pivot the contact plate around the pivot point thus formed in order to securely insert the insertion tab into the insertion opening. The walls of the housing-side receptacle also form a positioning aid, due to which the push-in tab is prepositioned too coarse with respect to the insertion opening in the context of the pivoting movement of the contact plate on the housing.

The development described above for a contact plate is preferably also provided for the other contact plate, so that both contact plates held in the same manner to the housing and introduced into this and prepositioned in the context and can be positively locked with the housing.

The housing preferably has a passage opening, which is usually part of the above-described receptacle for the contact lug. The passage surrounds circumferentially the contact lug and simplifies the installation of the same.

The aforementioned passage opening is preferably formed by an obliquely oriented passage. The passage channel extends obliquely to the direction of extension of the contact plates, which are usually provided parallel to one another and clamp the PTC elements between them. The lead-through channel is oriented obliquely so that the contact lug can be inserted through the lead-through channel at angles relative to its end position employed contact plate parallel to the passage channel limiting walls. The passageway is accordingly from the inside, i. the opening of the housing outwardly inclined towards the center (in the thickness direction) of the housing.

As already mentioned above, the housing is preferably a one-piece housing. This one-piece housing has only a single housing body, wherein the housing is formed in one piece and realized only as a unitary in itself rigid and dimensionally stable component.

In a conventional manner, the first wedge surface of the wedge element is usually with the interposition of a sliding plate against the associated contact plate, usually with the interposition of an insulating layer. According to a preferred embodiment of the present invention, however, the sliding plate is connected to the housing. As a result, a relative movement between the sliding plate and the housing is prevented. The sliding plate can be positively, positively or cohesively connected to the housing. For easier mounting of the sliding plate on the housing, this is preferably a positive fit connected to the housing. With a view to the insertion direction of the wedge element, it is preferable to connect the sliding plate without clearance at least at that end to the housing, which is associated with the narrower end face of the wedge element. Towards this end, the wedge element moves when tightening the heat generating element in the bag. At this narrower end is preferably provided on the sliding plate one, preferably a plurality of securing tabs, which cooperate with one, preferably a plurality of correspondingly provided for this purpose fuse openings of the housing and are accommodated in these.

According to a further preferred embodiment of the present invention, the sliding plate is connected at its two opposite end portions with the housing. The opposite end portions are formed by those ends of the sliding plate, which are assigned on the one hand, the narrower end surface and on the other hand, the wider end surface of the wedge element and regularly extend substantially parallel to these end surfaces. The corresponding end regions are accordingly usually in the direction of movement of the wedge element before or behind. In this case, the sliding plate is preferably connected at its the wider end face of the wedge element associated end by a latching connection form-fitting manner with the housing. This latching connection preferably comprises at least one resilient latching web formed by the sliding plate, which cooperates with a mating surface provided on the housing side. The latching web is usually formed by punching and bending of the sheet metal forming the sheet metal material and preferably projects beyond an end face of the wedge element associated and this area supporting sliding surface of the sliding plate. The latching web is usually located in the width direction centered on the sliding plate and preferably cooperates with a centrally arranged on the housing and integrally formed thereon latching projection. In this way, a simple connection of the sliding plate.

The sliding plate can first be introduced via the securing tab in the associated securing opening of the housing and pre-fixed there. A pivoting about the pivot point formed thereby brings the locking bar behind the locking projection, so that the sliding plate is latched at the opposite end portions of the housing with the housing. Both compounds are preferably form-fitting.

The sliding plate further preferably has retaining arms, which hold the wedge element displaceable. As a result, a structural unit is created, so that the heat-generating element can be used together with the wedge element held displaceably in the pocket. Compared to the known prior art, in which the heat-generating element is first introduced into the pocket and then the wedge element is introduced from above between the heat-generating element and an inner surface of the pocket (see. EP 1 921 896 A1 ), in this preferred embodiment, the heat-generating element as a unit and thus easily positioned and mounted in the bag. This embodiment may be essential to the invention. It is in particular provided with a sliding plate, which is connected at opposite end portions with the housing, so that the sliding plate on the one hand holds the wedge element and on the other hand securely fixed to the housing, preferably by means of positive engagement with this is connected. The support arms are typically spring arms which project from opposite edges of the slide plate, project beyond the sliding surface for the wedge member and are biased inwardly toward the wedge member, such that these resilient support arms typically engage the wedge member at side surfaces connecting the opposed wedge surfaces and in the region fix the wider end face of the wedge element. Although it is possible, the sliding plate for this fixation of the wedge element on the support arms only on one end side, ie the narrower end face of the wedge element associated side with the housing to lock and to fix the wedge member by a cross-housing part so that the wedge element of the sliding surface takes off. However, to be preferred is the support of the sliding plate by a detent web, which is associated with the wider end face of the wedge member and cooperates with the housing, since in such an embodiment, the housing on the connection side less expensive and in particular slimmer can be formed, which is the cycle time for injection molding shortened the housing and also simplifies the mold cavity geometry for molding the housing side of the injection mold.

Figur 1

eine perspektivische Draufsicht auf das Ausführungsbeispiel von einer ersten Oberseite;

Figur 2

eine perspektivische Draufsicht auf das Ausführungsbeispiel von einer zweiten Oberseite;

Figur 3

eine perspektivische Ansicht ähnlich Figur 2 beim Verbinden des Gleitblechs;

Figur 4

eine perspektivische Draufsicht ähnlich Figur 2 nach der Endmontage des Ausführungsbeispiels;

Figur 5

eine Längsschnittansicht entlang der Mittellängsachse des in Figur gezeigten fertig montierten Ausführungsbeispiels und

Figur 6

eine Längsschnittansicht entlang einer Linie parallel zu der Mittellängsachse verlaufenden Linie, welche die Einstecklasche eines Kontaktblechs schneidet.

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 top view of the embodiment of a first top side;

FIG. 2

a perspective top view of the embodiment of a second top side;

FIG. 3

a perspective view similar FIG. 2 when connecting the sliding plate;

FIG. 4

a perspective top view similar FIG. 2 after the final assembly of the embodiment;

FIG. 5

a longitudinal sectional view taken along the central longitudinal axis of the shown in Figure completely assembled embodiment and

FIG. 6

a longitudinal sectional view taken along a line parallel to the central longitudinal axis line which intersects the tuck of a contact plate.

The FIG. 1 shows a housing marked with reference numeral 2 of an embodiment when connecting this housing 2 with a first contact plate 4. The housing 2 forms an opening 6, the inner peripheral surface of which is integrally formed on the housing 2 formed spacers 8, which have a substantially pyramidal shape , wherein the surfaces of the spacer elements 8, which extend between a formed by the housing 2 flat edge 10 of the opening 6 and the tip of the spacer 8, are concavely shaped. These spacers 8 are used to create PTC elements, the FIG. 2 marked with reference numeral 12. The spacers 8 hold the PTC elements 12 upstanding to the rim 10 and accordingly increase the leakage current path.

The housing 2 is formed in the side view substantially wedge-shaped with a front, narrow end 14 and a wider end, which forms a connection side 16 of the housing 2. The opening 6 is bounded by edge surfaces 18, which are provided on both sides of the opening 6 and extend parallel to each other. These edge surfaces 18 surrounding the opening 6 are surrounded in the longitudinal direction of the housing 2 and at the front end 14 by a slightly widened outer edge 20, which projects beyond the edge surfaces 18 on both sides and is wedge-shaped in the longitudinal direction of the housing 2, ie at the front end 14 smaller width At the connection side 16, the housing 2 further forms a circumferential and widened collar 22, which projects beyond the contour of the outer edge 20 on the connection side 16 and forms a support surface 24, via which in a pocket of an electric Heater built-in housing 2 is supported on the upper side to a heater housing of the electric heater, as is made EP 1 921 896 A1 is known.

At the front end 14, there provided, transverse to the longitudinal extent of the housing 2 extending edge surface 18 of two insertion openings 26, 28 passes. In the FIG. 1 Front, marked with reference numeral 26 insertion opening serves to attach the in FIG. 1 For this purpose, this has an insertion tab 30, which projects beyond a front edge surface 32 of the contact sheet 4 and is formed by punching and bending. The tuck 30 has accordingly a smaller width than the contact plate 4 in the region of the front edge surface 32, which the tuck 30 forward - from the perspective of FIG. 1 - Slightly surmounted and slightly behind. The Einstecklasche 30 is opposite to a formed by the contact plate 4 bearing surface 34 for the PTC elements 12 by 90 ° and projects beyond this contact surface 34 inwards. The insertion tab 30 has an outwardly directed, at right angles to the contact surface 34 extending locking surface 36 which is surmounted by two locking projections 38. The latching projections 38 are formed by punching on the contact sheet 4 forming sheet material and project beyond the locking surface 36 as a convex-shaped locking cams.

The insertion opening 26 merges via a convexly curved mouth section 40 into the opening 6, which serves to abut a curved transition region 42 between the abutment surface 34 and the insertion tab 30. The mouth portion 40 is lower than the edge surface 18, so that in the installed state, the contact plate 4 is arranged flush with the edge surface 18.

At its opposite end of the tuck 30 end, a rear edge surface 44 of the contact plate 4 is surmounted by a contact lug 46, which is like the Einsteckfahne by free punching with respect to the associated edge surface 44 significantly smaller width is provided and projects beyond this. The contact lug 46 forms at its free end a contact tongue 48, via which the electrical connection to the contact plate 4 takes place and which projects beyond the housing 2 on the connection side 16.

Between this contact tongue 48 and the contact surface 34 of the contact plate 4, this forms a contact projection 50, which is given by free cutting a step in the contact lug 46. For receiving a length region of the contact lug 46, the edge surface 18 is pierced by a receptacle 52, the base of which extends parallel to the edge surface 18 and forms a contact surface for the contact lug 46. The receptacle 52 laterally delimiting edge 10 of the housing 2 forms an abutment shoulder 54, which is associated with the abutment projection 50 such that this strikes when inserting the contact tongue 48 in a recessed on the housing 2 passage opening 56, whereby the insertion movement comes to an end , In this position, the abutment projection 50 abuts against the abutment shoulder 54 in the manner of a swivel joint. By pivoting about this point the tuck 30 is forcibly pivoted into the insertion opening 26 and herein by cooperation of the locking projections 38 with a housing-side shaped locking projection 58 (see. FIG. 6 ) positively secured.

In particular FIG. 6 can be seen, the passage opening 56 is formed by an obliquely oriented passage 60. This oblique passage channel 60 is formed by a flattening 62 directed towards the center - in the width direction - which projects away from the edge surface 18, and a flattening 64 extending in parallel thereto and provided on a wall defining the passage opening 56 inside of the collar 22 is formed. It can be provided to form the passageway 60 also only the flattening 64 and be dispensed with the inclined surface 62.

Accordingly, in the widthwise direction of the exemplary embodiment, the oblique passage channel 60 extends outward from the edge surface 18 in the direction of the connection side 16 towards the widthwise center. As a result, the insertion of the contact lug 46 is facilitated by the passage opening 56 at obliquely aligned to the edge surface 18 contact plate 4. The walls defining the passage opening 56 also lead to an alignment of the contact plate 4 with its longitudinal edges 66 parallel to the associated edges 20 of the housing 2, so that the contact plate 4 is aligned after insertion of the contact lug 46 in the passage opening 56 so that the tuck 30 is aligned with the insertion opening 26.

After the contact plate 4 has been positively connected to the housing 2 in the manner described above, the housing 2 is rotated in the context of assembly, so that the in FIG. 1 page shown above comes down. This position is in FIG. 2 clarified. In the bottom closed by the contact plate 4 opening 6 now several, four PTC elements 12 are now introduced and placed on the contact surface 34 of the contact plate 4. Thereafter, a substantially identical to the contact plate 4 formed further contact plate 68 in the above with reference to FIG. 1 described manner aligned with the housing 2 and locked with this. The contact plate 68 is formed substantially identical to the contact plate 4 with the difference that to the individual PTC elements 12 each formed by punching and bending spring tongues 70 to improve the electrical contact a flat contact surface 72 of the contact plate 68 are formed outstanding.

As the FIGS. 1 and 2 make clear, a U-shaped recessed groove 74 is provided between the locking surface 18 and the outer edge 20. This groove 74 surrounds the U-shaped in contact with the above-described manner mounted contact plate 4 and 68 and serves to receive a sealant 76 which is introduced into the groove 74. This sealant 76 may have adhesive properties and is used for sealing and optionally also fixing a marked with reference numeral 78 insulating layer on the outside of the contact plate 4 and 68. This insulating layer 78 has present a two-layer structure with a silicone film and a glass fiber mat connected thereto. Such an insulating layer 78 exhibits a high electrical breakdown strength and can be produced with an exact thickness as a substantially incompressible insulating layer 78.

After applying the insulating layer 78 on the edge surfaces 18, the contact plates 4 and 68 are insulated from the environment. After that, on the in FIG. 2 upper side above a marked with reference numeral 80 sliding plate placed. This sliding plate 80 has at its front end 14 of the housing 2 associated end two locking tabs 82, each of which is in each case substantially identical to the insertion tabs 30 are formed with the difference that each of the locking tabs 82 is surmounted only by a locking projection 38. Corresponding to the two side by side provided in the width direction locking tabs 82 are on the housing 2 backup openings 84 recessed. The sliding plate 80 is described in the above with reference on the contact plate 4 described manner introduced with its locking tabs 82 in the associated securing holes 84 and positively connected to the housing 2. As FIG. 6 illustrates, the securing holes 84 are slightly conically widened upward, so that the sliding plate 80 is pivotable about the hinge formed between the locking hole 84 and locking tab 82 in limits. After the introduction of the securing tabs 82 in the securing holes 84, the sliding plate 80 takes in FIG. 3 shown position. Thereafter, the sliding plate 80 is applied over the entire surface against the housing 2.

The sliding plate 80 has at its the connection side 16 facing front end 86 a latching web 88 which is formed by punching and bending of the sliding plate 80 ausformenden sheet material and formed by the sliding plate 80 sliding surface 90 and is hook-shaped, so that the latching web 88 a is formed substantially perpendicular to the sliding surface 90 extending first portion 92 and in turn at right angles thereto and parallel to the sliding surface 90 inwardly extending second portion 94 is formed. To increase the flexural rigidity of the locking web 88 of this is formed by a bending formed by bending, extending in the longitudinal direction of the housing 2 bead 96, which is bent outwards. The second section 94 has a funnel-shaped outwardly widening free end.

By punching and bending are in the upper third of the sliding plate 80, i. that area, which is assigned to the connection side 16, formed cheeks 98, which limit the sliding surface 90 edge, but in the mounted state not higher above the edge surfaces 18 protrude than the wedge-shaped outer edges 20 at the level of the corresponding cheeks 98. The cheeks 98 go connection side in spring arms 100 over, which are cut free relative to the flat surface 90 and inwardly arc.

The collar 22 is on in the FIGS. 2 to 4 shown side provided with two large apertures 102, between which a support web 104 is integrally formed on the housing 2, which forms an inwardly projecting latching projection 106 at its free end. The latching projection 106 lies within an envelope surface around the collar 22.

When pivoting the sliding plate 80 of the in FIG. 3 shown preliminary orientation in the in the FIGS. 4 to 6 shown end position of the locking bar 88 is urged by the locking projection 106 inwardly and springs back upon reaching the end position of the sliding plate 80, so that the sliding plate 80 is also held on the connection side 16 form-fitting manner to the housing 2.

On the in this way with the housing 2 connected to opposite end portions sliding plate 80 is now marked with a reference numeral 108 wedge element is placed (see. FIGS. 4 to 6 ). The wedge member 108 has a broader end surface labeled 110, which is associated with the terminal side 16, and a narrower end surface, indicated at 112, associated with the forward end 14. The wedge element 108 has a width such that the wedge element 108 is frictionally held between the spring arms 100. In the in FIG. 4 shown starting position, the wedge member 108 is further overlapped by the second portion 94 of the locking bar 88 and accordingly held positively between this portion 94 and the sliding surface 90. In this starting position lies an in FIG. 6 designated by reference numeral 114, the first wedge surface parallel to the sliding surface 90, which in turn extends parallel to the contact plate 68, whereas a marked with reference numeral 116 second wedge surface on the outside of the housing 2 is exposed. In the in FIG. 6 shown initial position, this second wedge surface 116 is still slightly below the given by the outer edge 20 contour. By moving from right to left (according to FIG. 6 ) and due to the wedge-shaped configuration of the wedge element 108 at an angle of about 3 ° finally the wedge element 108 projects beyond this contour and braces accordingly in the FIGS. 4 to 6 illustrated embodiment of a heat generating element 120 in a tapered pocket of an electric heater. On the opposite side of the wedge member 108, the insulating layer 78 is exposed to the housing 2 and approximately flush with the contour of the edge provided on this side 20. Usually, the insulating layer 78 projects slightly beyond this edge.

In particular FIG. 5 illustrates, the front free end of the second portion 94 of the locking ridge 88 is still within the support surface 24, so that the positioning of the heat generating element 120 to the heater housing is not affected by the support of the wedge member 108. The insertion of the wedge element is done by inserting two tool projections through the aperture 102. The wedge member 108 has a trough at its widened end 110 so that the corresponding tools are well positioned on the wedge member 108.

LIST OF REFERENCE NUMBERS

2

casing

4

contact sheet

6

opening

8th

spacer

10

edge

12

PTC element

14

front end

16

terminal side

18

edge surface

20

outer edge

22

collar

24

support surface

26

insertion

28

insertion

30

tuck

32

front edge surface

34

contact surface

36

Rest area

38

catch projection

40

mouth portion

42

Transition area

44

rear edge surface

46

contact tag

48

contact tongue

50

abutment projection

52

admission

54

contact shoulder

56

Through opening

58

locking projection

60

Through channel

62

flattening

64

flattening

66

longitudinal edge

68

contact sheet

70

spring tongue

72

contact surface

74

groove

76

sealant

78

insulating

80

sliding

82

securing tab

84

securing aperture

86

frontal end

88

latching web

90

sliding surface

92

first section

94

second part

96

Beading

98

cheek

100

spring arm

102

perforation

104

supporting web

106

catch projection

108

key member

110

wider endface

112

narrower endface

114

first wedge surface

116

second wedge surface

120

Heat generating element

Claims (14)

1. Heat generating element (120) with at least one PTC element (12), contact sheets (4, 68) flatly lying against it on either side, a housing (2) which forms at least one opening (6) for receiving the at least one PTC element (12) and has a terminal side (16) at which contact tongues (48) allocated to the contact sheets (4, 68) are exposed,
   characterized in
   that at least one of the contact sheets (4, 68) has a bent-over tongue (30) which is received in an insertion opening (26, 28) formed by the housing (2).
2. Heat generating element (120) according to claim 1, characterized in that the tongue (30) is formed by a cut-free insertion lug.
3. Heat generating element (120) according to claim 1 or 2, characterized in that at least one latching projection (38) which is latched with the housing (2) projects from a surface (36) of the tongue (30) oriented essentially at right angles to a locating surface (34) for the PTC element (12).
4. Heat generating element (120) according to one of the preceding claims, characterized in that the latching projection (38) is formed by processing by punching the contact sheet (4).
5. Heat generating element (120) according to one of the preceding claims, characterized in that the contact sheet (4) comprises a locating projection (50) between the contact tongue (48) and the locating surface (34), that the housing (2) comprises a locating shoulder (54) allocated to the locating projection (50), and that the housing (2) and the contact sheet (4) are dimensioned such that the tongue (30) can be introduced into the insertion opening (26) by swiveling around the locating shoulder (54) when the locating projection (50) is lying against the locating shoulder (54).
6. Heat generating element (120) according to one of the preceding claims, characterized in that the other contact sheet (68) also comprises a bent-over tongue (30) which is received in an insertion opening (28) formed by the housing (2).
7. Heat generating element (120) according to claim 6, characterized in that the other contact sheet (68) is further developed according to one of claims 2 to 5.
8. Heat generating element (120) according to one of the preceding claims, characterized in that the housing (2) has a through hole (56) for an end of a contact lug (46) formed at the contact sheet (4, 68) by punching, the end being provided with the contact tongue (48).
9. Heat generating element (120) according to claim 8, characterized in that the through hole (56) is formed by an obliquely oriented lead-through channel (60).
10. Heat generating element (120) according to one of the preceding claims, characterized by a wedge element (108) with a broader and a narrower end face (110, 112) which are connected to each other via first and second wedge surfaces (114, 116), the first wedge surface (114) extending in parallel to one of the contact sheets (68) and lying against it with a slide plate (80) being inserted, the second wedge surface (116) being exposed at the outer side of the housing (2), and the slide plate (80) being connected to the housing (2).
11. Heat generating element (120) according to claim 10, characterized in that the slide plate (80) comprises a securing bracket (82) which is received in a securing opening (84) formed by the housing (2).
12. Heat generating element (120) according to claim 10 or 11, characterized in that the slide plate (80) is, at its end allocated to the broader end face (110) of the wedge element (108), connected to the housing (2) with a form-fit by a latching connection which has at least one resilient latching web (88) formed b the slide plate (80).
13. Heat generating element (120) according to claim 12, characterized in that the latching web (88) grips over the wedge element (108) in a starting position.
14. Heat generating element (120) according to one of claims 10 to 13, characterized in that the slide plate (80) comprises retaining arms (100) which movably hold the wedge element (108).

Images