EP2608631B1 - Element which produces heat - Google Patents

Description

The present invention relates to a heat generating element, in particular for an electrical heating device of a motor vehicle, having a position frame which forms a receptacle in which at least one PTC element is accommodated, and two contact plates resting on opposite sides of the PTC element.

Such heat-generating elements are generally known as part of an electric heater, in particular for air heating in a motor vehicle, which is also to be developed with the present invention. The heat-generating element forms a layer of a layer structure, which usually comprises corrugated rib elements resting on both sides of the heat-generating element. This layer structure usually has a plurality of layers of corrugated rib elements and heat-generating elements, which are in each case stacked in a plane one above the other.

As generically, for example, the EP 1 768 457 A1 and the EP 1 768 458 A1 be considered. Also the EP 0 350 528 discloses a generic heat generating element as part of an electric heater for air heating.

A corresponding tubular element is from the US 2008/0173637 known. In this prior art, a PTC element is wrapped with contact plates lying on both sides in an electrically insulating sheath and pressed into a tube which is closed at its opposite end sides via plugs, being passed through a plug through electrical connection cable to the contact plates.

The suggestions going back to the applicant after EP 1768 457 A1 and EP 1 768 458 A1 specify heat-generating elements and electric heaters with those which are suitable for the operation with high currents in an improved manner. In this context it is important to increase clearance and creepage distances. Furthermore, for good insulating support, the elements conducting the power current to the PTC elements are within the heat generating element and within the electric heater. For example, with the proposed solution after the EP 1 768 457 A1 a heat generating element specified in which the contact plates are covered on the outside by an insulating layer which is fully bonded to the position frame. This is to prevent moisture and contamination from entering the heat generating element.

However, the last-presented solution can only show the desired effect if the seal of the receptacle for the PTC elements or is reliably sealed against the atmosphere. Thus, the present invention addresses the problem of providing a heat generating element and an electric heater, which are in practice in an improved manner for the operation with high currents. Furthermore, the present invention seeks to provide a method of manufacturing such an electric heater.

With its first aspect, the present invention proposes to achieve the above object a heat generating element having the features of claim 1, which differs from the previously discussed prior art in that the receptacle is accessible via at least one externally accessible test channel. The sealed receptacle captures the PTC element (s) within the position frame hermetically protected from atmospheric influences. Nevertheless, a defined access to the recording is created by a test channel accessible from the outside. The test channel is used in the production of the heat generating element of the quality control and allows the determination of whether the sealing of the PTC element was actually realized within the heat generating element in the desired quality. Accordingly, the test channel is sealed after installation of the heat generating element in a heater to the atmosphere, for example by sealing the test channel, for example, immediately after the review of the heat generating element.

However, it is preferable to carry out the leak test after assembling the electric heater in view of economically checking the tightness and checking the tightness of the mounting frame in the electric heater. Thus, it is proposed according to a preferred embodiment of the present invention to surround the test channel of a connection piece, which protrudes from the position frame. The position frame is regularly a component with sections of straight edge surfaces. The position frame is usually a frame in the classical sense with opposing longitudinal and transverse bars. Usually, at least one connecting piece is provided on a spar, usually a transverse spar, which has a smaller extent relative to the longitudinal spar. The connecting piece allows in an improved manner a connection of the heat-generating element for leak testing, since the nozzle can be used by its outer peripheral or end faces in a defined manner in a channel for leak testing. In view of this, it is further proposed to surround the connecting piece preferably by a sealing element. This sealing element serves not only the seal in the context of leak testing, but also the sealed installation of the heat generating element in the electric heater.

If, as a further development of the present invention suggests, the connecting piece forms a channel for a contact element which is electrically conductively connected to one of the contact plates, the heat-generating element can be electrically sealed in a simple manner to lines for the power current. In this case, usually the heat-generating element is initially completed with its layers. These layers include at least the contact sheets which are regularly covered on the outside by an insulating layer and the PTC element or elements interposed therebetween. Corresponding contact sheets are usually formed by punching, optionally bending from a metal strip. The insulating layer may be formed of a plastic film and / or a ceramic layer. The insulating layer can also be provided by spraying plastic and / or ceramic on the outer surface of the contact plate and / or the inner surface of a sheet metal cover, the in any case on one side can surround the heat-generating element on the outside and which acts as a shield against electromagnetic radiation.

With its secondary aspect, the present invention proposes to solve the above problem, an electric heater, in particular for a motor vehicle with the features of claim 5. This electric heater has a frame which forms on opposite sides openings for the passage of a medium to be heated. The openings usually extend at right angles to the direction of flow of the medium to be heated and are on both sides of frame beams, which are regularly formed to form a rectangular frame as longitudinal or transverse bars and surrounded a receiving space for a layer structure. This layer structure has layers of corrugated and heat generating elements. In this case, at least one heat-generating element and a corrugated fin element is provided in the frame. Usually lie on each side of the heat generating element each corrugated fin elements. Periodically, an electric heater for effectively heating air in a vehicle is formed by a plurality of heat generating elements against which corrugated fin elements abut respectively. The heat generating element comprises at least one PTC element, which is arranged between two contact plates, which serve to energize the PTC element. The electric heater further has a connector housing. The terminal housing is used regularly to connect selected, sometimes all contact plates to a control device which is accommodated in the connection housing. This control device usually includes a populated board. Often this is now equipped with at least one semiconductor power switch, which controls the heat generating elements and thereby generates power loss that must be dissipated regularly by cooling the circuit breaker.

The connection housing is usually formed at least in two parts with a housing base and a housing cover, which include the control device and are regularly releasably connected to each other to make the control device accessible for repair or maintenance purposes.

The electric heating device according to the invention is now designed in a special way for receiving the heat-generating element according to the present invention and has at least one nozzle receptacle formed on the connection housing for sealingly receiving a connection piece projecting from the heat-generating element. Accordingly, the connection housing designed according to the invention, in cooperation with the connecting piece of the heat-generating element, allows a sealed mounting of the heat-generating element in the connection housing. The receptacle formed by the heat generating elements is accordingly sealed by the connection housing. The recording is, however, also accessible via the terminal housing, for example, to introduce contact elements in the heat-generating element. But it is also possible, after complete installation of all heat-generating elements to perform on the terminal housing on this a leak test, so that essentially the finished assembled electric heater is checked for leaks. In this case, the nozzle receptacle is usually formed by a housing base, so that after the leakage test only the housing cover, possibly previously electronic component must be used to complete the electric heater with it in a structural unit provided thereon control device.

Regularly, each of the contact elements of the heat-generating element is provided with a separate connection piece which is sealed off in a nozzle receptacle. But it is also possible to provide a connecting piece, which receives all electrical conductors to the interior of the heat generating element in and is sealingly received in the nozzle receiving the connection housing.

According to a preferred embodiment of the present invention is located between the nozzle and the nozzle receiving a sealing element made of an elastomeric material. This sealing element is applied in a practical manner before mounting on the nozzle and can be connected by over-molding. As a result of this cohesive connection, a connection, which is in any case tight, between the sealing element and the associated contact surface, which may be a surface of the heat-generating element and a surface of the connection housing, takes place on at least one side.

With a view to a simple plug-in contact of the heat-generating element is proposed according to a preferred embodiment of the present invention to provide a contact element which protrudes from the nozzle and is electrically connected to one of the contact plates of the heat generating element. The contact element is dimensioned so that the nozzle receptacle is dominated by the contact element, so that it can be connected electrically on the side of the connection housing simply via a plug connection, for example by introducing a connector receptacle of a printed circuit board.

To increase the clearance and creepage distances and thus with a view to a higher electrical safety of the electric heater is proposed according to a preferred embodiment of the present invention that between two contact elements each having a heat generating element, which are exposed in the terminal housing, a divider is provided. This divider protrudes beyond a contact surface for contact surface elements. For example, printed circuit boards may be provided as contact surface elements via which different heat-generating elements are electrically connected, if necessary also grouped together to form heating stages. Because of the need to energize the heat generating elements with different polarity, at least two such contact surface elements are provided in the terminal housing, namely a contact surface element for the positive pole and a contact surface element for the negative pole. If the electrical potential of the electrical heating device drops to ground, the negative pole is to be regarded as the negative pole in this sense.

The terminal housing is usually formed of plastic or at least formed for corresponding circuit boards usually made of plastic investment points. In any case, these contact points are in the case of planar contact surface elements in one plane and define the contact surface. The divider overhangs this contact surface, regularly in the direction of extension of the contact elements, and accordingly increases the air and creepage distance between the contact surface elements of different polarity. The divider can also divide the entire terminal housing in housing receiving areas and additionally sealed by a housing cover end.

According to a preferred development of the present invention, the electric heating device has a cooling body which is flowed by the medium to be heated. This heat sink is sealed inserted into the terminal housing and thermally conductively connected to a circuit breaker, which is accommodated in the terminal housing. Accordingly, the connection housing usually has at least one introduction opening, which is penetrated by the heat sink, so that inside the connection housing the circuit breaker can rest on the heat sink and on the other hand the heat sink is exposed in the region of a power section of the electrical heating device and can be illuminated by the medium to be heated. to dissipate power loss of the circuit breaker. In this passage opening for the heat sink is usually a sealing element which bridges and seals a gap between the heat sink and the contours of the terminal housing. The sealing element can be inserted or provided by injection-molding, in particular on a connection housing formed from plastic.

In this case, the sealing element is preferably designed so that the cooling body is held movably in the direction of insertion within a cooling body insertion opening formed by the connection housing. This mobility of the heat sink within the heat sink inlet opening in the direction of introduction has the advantage that the heat sink can avoid a pressure applied to the side of the connection housing within limits without being forced out through the heat sink inlet opening. So can the Heat sink under bias to be applied to a power transistor. The bias voltage can be generated by a separate biasing means, for example by acting on the heat sink or the circuit breaker spring element.

Preferably, however, the bias is effected by compression of a seal effecting element. In contrast to the known prior art, the present invention assumes that the heat sink is usually attached directly to the terminal housing and not mounted on a circuit board or the like, which carries the circuit breaker.

According to its secondary aspect, the present invention further proposes a method for manufacturing an electric heating device with the features of claim 10. In this method, first several heat generating elements of the type described above are produced. Furthermore, corrugated rib elements are usually produced by meandering bending of a sheet metal strip. As corrugated rib elements in the context of the present invention but are also to be considered extruded aluminum. The individual webs of such profiles form the corrugated ribs of said corrugated fin element. Furthermore, a connection housing is produced. This can be wholly or partly formed by a cast metal part or an injection-molded plastic part. The inventive method is characterized in that the tightness of the heat-generating elements is checked in the context of production. This check can be performed on each individual heat generating element to eliminate very early in the manufacturing process auszusondernde heat generating elements.

However, the tightness should preferably be checked for reasons of speedy and therefore economical production, after the heat generating elements are installed in the terminal housing. This check is usually carried out after the complete installation of the layer structure in the frame. Accordingly, the terminal housing is placed on the thus preassembled frame. By placing the connection housing there is a sealed connection between the individual heat-generating elements and the connection housing. This can then be pressurized at an interface.

The leak test is usually carried out by applying an overpressure relative to the atmospheric pressure. The pressure level and its course is monitored over a certain period of time. If there is no substantial reduction of the overpressure within the electric heater or the heat generating element, so the component has passed the leak test. With a looming loss of overpressure over time, a leak is concluded. The heat generating element, optionally the mounted electric heater, is discarded. In view of this, the leak test is preferably performed before the controller is installed in the terminal housing.

The present invention is particularly guided by the notion that the terminal housing has a housing base which forms a flat abutment edge for a housing cover. About this contact edge, a nozzle of a leak tester can be applied to put the preassembled electric heater under pressure and perform the leak test.

According to a preferred embodiment of the method according to the invention, the contact plates of the heat-generating elements are clipped to the position frame. In the same way, the contact plates are preferably clipped with contact elements, which are introduced into the position frame. Accordingly, first the heat generating element is produced with its layers. In the context of this production, the contact plates are usually covered externally with an insulating layer. This insulating layer is applied sealingly to the position frame, usually glued. The contact plates are preferably clipped with the contact elements. The contact elements are usually formed by metal pins. The contact plates are formed by punching and bending so that they can clasp with the pins, on the one hand to hold the contact plates in a simple manner to the positioning frame, for example, pre-fix in the context of assembly, and on the other hand in a simple way an electrical contact between the contact elements and to produce the contact sheets.

Figur 1

eine perspektivische Seitenansicht eines Ausführungsbeispiels einer elektrischen Heizvorrichtung für ein Kraftfahrzeug;

Figur 2

eine perspektivische Seitenansicht in Explosionsdarstellung eines Wärme erzeugenden Elementes der in Figur 1 gezeigten elektrischen Heizvorrichtung;

Figur 3

eine perspektivische Stirnseitenansicht des in Figur 2 gezeigten Ausführungsbeispiels;

Figur 4

eine perspektivische Seitenansicht des in Figur 1 gezeigten Ausführungsbeispiels in einer Explosionsdarstellung der wesentlichen Bestandteile des Ausführungsbeispiels;

Figur 5

einen Fügebereich zwischen einem Anschlussgehäuse und einem Schichtaufbau des in den Figuren 1 und 4 gezeigten Ausführungsbeispiels einer elektrischen Heizvorrichtung unter Weglassung verschiedener Elemente;

Figur 6

eine Querschnittsdarstellung entlang der Linie VI-VI gemäß Figur 1, d.h. eine Schnittansicht durch ein Wärme erzeugendes Element nach Figur 2 auf mittlerer Höhe desselben unter Weglassung des Abschirmgehäuses;

Figur 7

eine perspektivische Stirnseitenansicht des in Figur 1 gezeigten Ausführungsbeispiels einer elektrischen Heizvorrichtung, welche Einblick in das Anschlussgehäuse gibt und bei dem die Leiterplatte sowie der Gehäusedeckel fehlen;

Figur 8

das in Figur 7 gezeichnete Detail VIII in vergrößerter Darstellung;

Figur 9

eine Querschnittansicht des Anschlussgehäuses der elektrischen Heizvorrichtung nach Figur 1 auf Höhe eine Kühlkörpers;

Figur 10

eine perspektivische Seitenansicht eines ersten Ausführungsbeispiels eines Heizstabes, welcher in der elektrischen Heizvorrichtung nach Figur 1 eingebaut sein kann;

Figur 11

eine Querschnittsansicht entlang der Linie XI-XI gemäß der Darstellung in Figur 10;

Figur 12

eine Seitenansicht des in Figur 10 gezeigten Ausführungsbeispiel eines Heizstabes;

Figur 13

eine perspektivische Seitenansicht gemäß Figur 10 eines alternativen Ausführungsbeispiels eines Heizstabes;

Figur 14

eine Querschnittsansicht entlang der Linie XIV-XIV gemäß der Darstellung in Figur 13;

Figur 15

eine Seitenansicht des in Figur 13 gezeigten weiteren Ausführungsbeispiels eines Heizstabes;

Figur 16

eine perspektivische Explosionsdarstellung eines zur Aufnahme von Heizstäben nach den Figuren 13 bis 15 geeigneten Rahmens;

Figur 17

eine Schichten des geschichteten Aufbaus teilweise weglassende perspektivische Draufsicht auf den randseitigen Bereich eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Heizvorrichtung und

Figur 18

eine teilweise weggeschnittene perspektivische Seitenansicht des in Figur 17 gezeigten Ausführungsbeispiels.

Further details and advantages of the present invention will become apparent from the following description of embodiments in conjunction with the drawings. The drawing shows both the basic structure of an electric heater, in which a heat-emitting element, which may be essential to the invention, is installed. In the drawing show:

FIG. 1

a side perspective view of an embodiment of an electric heating device for a motor vehicle;

FIG. 2

an exploded perspective side view of a heat generating element of FIG. 1 shown electric heater;

FIG. 3

a perspective front view of the in FIG. 2 shown embodiment;

FIG. 4

a side perspective view of the FIG. 1 embodiment shown in an exploded view of the essential components of the embodiment;

FIG. 5

a joining region between a connection housing and a layer structure of the in the FIGS. 1 and 4 shown embodiment of an electric heater omitting various elements;

FIG. 6

a cross-sectional view along the line VI-VI according to FIG. 1 , ie a sectional view through a heat-generating element according to FIG. 2 at the middle height of the same, omitting the shielding housing;

FIG. 7

a perspective front view of the in FIG. 1 shown embodiment of an electric heater, which gives insight into the terminal housing and in which the circuit board and the housing cover are missing;

FIG. 8

this in FIG. 7 drawn detail VIII in an enlarged view;

FIG. 9

a cross-sectional view of the terminal housing of the electric heater according to FIG. 1 at the height of a heat sink;

FIG. 10

a side perspective view of a first embodiment of a heating rod, which in the electric heater according to FIG. 1 can be installed;

FIG. 11

a cross-sectional view along the line XI-XI as shown in Figure 10;

FIG. 12

a side view of the in FIG. 10 shown embodiment of a heating element;

FIG. 13

a perspective side view according to FIG. 10 an alternative embodiment of a heating element;

FIG. 14

a cross-sectional view along the line XIV-XIV as shown in FIG FIG. 13 ;

FIG. 15

a side view of the in FIG. 13 shown another embodiment of a heating element;

FIG. 16

an exploded perspective view of a recording of heating rods according to the FIGS. 13 to 15 appropriate framework;

FIG. 17

a layer of the layered structure partially omitting perspective top view of the edge region of another embodiment of a heating device according to the invention and

FIG. 18

a partially cutaway perspective side view of the FIG. 17 shown embodiment.

The FIG. 1 shows an embodiment of an electric heater with a marked with reference numeral 2 power and a part marked with reference numeral 4 control part. The power part 2 and the control part 4 form a structural unit of the electric heater.

The control part 4 is formed on the outside by a connection housing 6, which - in particular the representation according to FIG FIG. 4 illustrates - from a shield 8, which is formed as, for example, deep-drawn or cast or deep-drawn metal shell, a plastic housing element 10, which is inserted into the metal shell 8, and a housing cover 12 is made. The housing cover 12 may overlap a free flange of the sheet metal trough 8 in the assembled state and be formed of metal, so that the interior of the control part 4 completely by a metallic terminal housing 6 is shielded. The housing cover 12 may also be formed of plastic.

The housing cover 12 carries a female connector housing 14 for the power current and another female and designed as a control connector housing 16 housing element. Both connector housings 14, 16 are connected as plastic elements with the metallic housing cover 12 and form guide and sliding surfaces for each unillustrated male connector element.

The plastic housing element 10 receives a printed circuit board 18 in itself, which is partially covered by a pressure element 20, which will be explained in more detail below. The printed circuit board 18 is surmounted by a plus terminal plug contact 22 and a minus plug contact, which are exposed in the power plug housing and are electrically connected to the conductor track. The circuit board 18 also carries a control contact element containing control contact element 26, which is accessible via the control connector housing 16 by means of cables. How out FIG. 4 As can be seen, the control connector housing 16 is arranged offset to the control contact element 26. This distance is due to the installation situation of the electric heater in the motor vehicle. The electrical contact between the control contact element 26 and the control connector housing 16, or the contact elements provided there via electrical lines, which are laid inside the housing cover 12. The housing cover is further surmounted in the mounted state by a connection pin 28 for the ground connection, which is electrically connected to the shielding housing 8.

On the opposite side of the printed circuit board 18, the plastic housing member 10 forms two cooling channels 30 for heat sink 32, which in FIG. 4 just hinted at, while in the FIGS. 1 and 5 can be seen more clearly. The free end of the heat sink 32 includes a plurality of cooling webs extending substantially parallel to each other, each defining air passageways 34. The heat sink 32 are made of a good thermal conductivity material, such as aluminum or copper.

In the FIG. 5 not shown, omitted metal shell 8 has - as in particular the FIGS. 1 and 4 illustrate, corresponding to the cooling channels 30 opposite passage openings 36 for air, which are provided as inlet and outlet openings to the cooling channels 30. These passage openings 36 are in the metal shell 8 emerged. In about the middle height in the longitudinal direction of the metal shell has 8 locking openings 38 which are penetrated by the final assembly of the control part 4 on the power part 2 of locking lugs 40 which are integrally formed with the power part 2 in a form-fitting engagement and on the outer edge of the plastic housing element 10. The metal shell 8 also has on opposite end faces each mounting holes 42, which will be discussed in more detail below.

The power unit 2 has a frame 44, which in the embodiment according to FIG. 1 is circumferentially closed and a designated by reference numeral 46 layer structure, which is also referred to as a heating block, circumferentially surrounds. The frame 44 is formed from two frame members 48, which are locked together by latching connections, the reference numeral 50 (male latching element) and reference numeral 52 (female latching element), in particular in FIG. 16 Marked are.

The frame 44 forms on opposite outer sides 54 each openings 56 for the passage of air to be heated of the air heater shown in the embodiment. These openings 56 are stiffened in the embodiment shown by transverse struts 58, the opposite side edges of the frame 44 interconnect.

The frame 44 defines in its interior a receiving space 60 which is adapted such that the layer structure 46 can be received in the frame 44 closely fitted.

The heating block or layer structure 46 is essentially made of the in the Figures 10 and 13 formed heating rods 62 which are stacked in the receptacle 60 are arranged. The heating elements 62 consist of at least two corrugated fin elements 64, which receive a heat generating element 66 between them. As the Figures 10 and 11 illustrate, the corrugated rib elements consist of meandering curved metal strips 68, which are covered on one side by a metal cover 70 and also bordered by a curved edge 72 of the sheet metal cover 70. The respective other upper side of the meandering bent sheet-metal strip 68 is free and is formed directly by arcuate free ends 74 of the sheet metal stiffener 68. In the in the Figures 10 and 11 shown heater 62 are in the direction of passage of the air to be heated, ie perpendicular to the plane defined by the outer sides 54 surface of the frame 44 two corrugated fin elements 64 each provided side by side. This arrangement of corrugated fins 64 provided in succession in the direction of flow forms a layer. In each case, a corrugated fin element 64 per level E is provided in each position marked with the reference symbol L. With S, the flow direction of the air flow to be heated in FIG. 11 located. This firstly meets the first plane E1, ie the corrugated rib elements 64 of the first layer L1 and the second layer L2 provided in the first plane, and only thereafter onto the corrugated rib elements 64 provided in the second plane E2. The corrugated rib elements 64 are in the flow direction S. , ie, arranged at right angles to each other at right angles to the outside 54 defining the opening 56. In this case, the heat-generating element 66 forms a planar contact surface for the corrugated rib elements 64.

In particular FIG. 2 illustrates, the heat generating element 66 consists of several superimposed layers. The heat-generating element 66 has a substantially symmetrical construction, wherein in the middle of a marked with reference numeral 76 position frame of an electrically insulating material, in particular plastic is provided. In the present case, the positioning frame 76 forms three receptacles 78 for PTC elements 80. A receptacle 78 accommodates a plurality of at least two PTC elements 80. The two outer receptacles 78 each receive four PTC elements 80. On opposite sides of the PTC elements 80 contact plates 82 abut. These two contact plates 82 are identical and formed from punched electrically conductive sheet. The contact plates 82 are placed on the PTC elements 80 as separate elements. These may additionally be provided with a vapor-deposited electrode layer, as is common practice. However, the electrode layer is not contact plate 82 in the sense of the invention.

In particular FIG. 11 illustrates, the associated with a plane E1 PTC element 80 within the front and rear sides of the associated corrugated fin elements 64. In other words, located between two provided in a layer L1 corrugated fin elements 64 no PTC element 80. This is a thermal interaction between the PTC elements of different levels E1, E2 avoided.

The contact plates 82 are dimensioned so that they are indeed received within the position frame 76, but circumferentially spaced from the position frame 76 are arranged. The extent gap formed in this respect is in FIG. 11 with reference number 84 characterized. In approximately at the level of the contact plates 82 of the positioning frame 76 forms a circumferential sealing groove 86, in which an elastomeric adhesive edge 88 is filled as a torus. This adhesive edge 88 surrounds all receptacles 78 fully circumferentially and serves to bond an insulating layer identified by reference numeral 90, which in the present case is formed from an insulating plastic film and which extends to an edge region of the positioning frame 76, in each case in the circumferential direction the adhesive edge 88 surmounted with excess. By the connection of the insulating layer 90 with the position frame 76 mediated by the adhesive edge 88, the receptacle 78 and the contact plates 82 is hermetically sealed against the outer periphery.

Access to the interior of the positioning frame 76 are provided solely on an end face of the positioning frame 76 and through its material integrally formed thereon connecting pieces 92 which surround a channel 94 for receiving pin-shaped contact elements 96 full extent. At its free end, the connecting pieces 92 are made of a thermoplastic elastomer or PTFE sealing elements 98 formed with labyrinth-like sealing structure, which can be connected by injection molding or plugging with the associated connection piece 92. On the front side of each position frame 76, two connecting pieces 92 are provided with identical design and sealing for receiving two contact pins 96 for electrical contacting of the contact plates 82nd

As before FIG. 2 it can be seen, the contact plates 82 have been made by punching and bending female clip element receptacles 100 which are formed on laterally offset projections 102 of the contact plate 82, which projections 102 terminate within the given by the adhesive edge 88 border and respectively assigned and by the positioning frame 76th cover formed clip openings 104, 106. In the connection openings 92 opposite to the formed on the positioning frame 76 clip openings 106 are integrally formed thereon by the material of the positioning frame 76 clip webs 108 are provided. The configuration and the diameter of these clip webs 108 correspond to the diameter of a contact pin 96. The contact pins 96 are exposed in the clip openings 104 and are connected to the female clip element receptacles 100 of the contact plates 82, whereas on the opposite side the female clip element receptacles 100 project into the clip openings 106 and are locked with the clip webs 108. At the connecting piece 92 having the connection side of the heat generating element 66, the described Clip connections can be realized either by positioning the contact plates 82 in their installed position and subsequent insertion of the contact pins 96 through the channels 94 or by locking the female clip element receptacles 100 with the contact pins 96 already in position.

On his in FIG. 2 shown top side, the heat generating element 66 is provided with a metal cover 110. This metal cover 110 covers the entire, the sheet metal cover 110 associated insulating layer 90 and has a peripheral edge 112 which frictionally rests against a peripheral edge surface 114 of the position frame 76 and, accordingly, the sheet metal cover 110 by biasing force on the position frame 76 secures (see also Fig. 11 ). Furthermore, the edge 112 ensures accurate positioning of the sheet metal cover 110 relative to the outer periphery of the position frame. The metal cover 110 has at the free end of the rim 112 a slight conical broadening, which acts as a funnel-shaped insertion opening for the position frame. The peripheral edge 112 is broken only in the corner areas and at the height of the connecting piece 92 and forms a one-sided shield for the heat generating element 66th

As FIG. 3 illustrates, the channels 94 adapted to the contact pins 96 are radially widened to form a groove-shaped test channel 116. This test channel 116 extends from the front free end side of the connecting piece 92 to the associated clip opening 104 and accordingly forms an external access to the receptacles 78, which communicate with each other below the insulating layer 90 and the contact plates 82.

As FIG. 3 Furthermore, illustrates the sheet metal cover 110 between the slightly upwardly arched shoulder portions 118 for the peripheral edge 112 a flat contact surface. Accordingly, these attachment areas 118 form a kind of centering for the corrugated rib elements 64 (see also FIG FIG. 11 ).

The layer structure 46 described above is held in the embodiment shown under spring tension in the frame 44. For this purpose, the frame 44 formed by the two frame members 48 spring insertion openings 120, which in the FIGS. 4 and 5 can be seen and not yet mounted heater on the control side Face of power section 2 are exposed. In these Federeinbringöffnungen 120 braced spring elements 121 are introduced, which in the Applicant going back EP 2 298 582 are described and their disclosure content is incorporated by this reference in the disclosure of the present application. Immediately adjacent to these spring insertion apertures 120, each of the frame members 48 each form a retainer member 122. Each holding element part 122 formed by a frame element 48 is provided with an inclined ramp surface 124. The holding element parts 122 are designed such that, when the frame 44 is joined, two holding element parts 122 respectively assigned to a frame element 48 form complete holding elements 126 on opposite end sides with the frame element parts 122 of the other frame element. These holding elements 126 have a tapering towards the free end configuration, so that the inclined ramp surfaces 124 for coarse positioning of the control part 4, namely a positioning opening 127 of the plastic housing element 10 relative to the power unit 2 are used (see. Fig. 5 ). Furthermore, grooves 128 extending transversely to the holding element parts 122 form a circumferentially closed bore 130 after joining the frame elements 48 (cf. Fig. 4 ). In this bore 130, a fastening screw can be introduced through the mounting hole 42 of the metal shell 8 to effect the positioning and fixing of the power section 2 to the control part 4 to achieve a structural unit of power section 2 and control section 4.

As the Figures 5 and 6 illustrate, the plastic housing member 10 forms for each heat-generating element 66 two cylindrical nozzle receivers 132, which are adapted such that the connecting pieces 42 can be introduced together with the sealing elements 98 each in associated nozzle receptacles 132 sealing. As FIG. 6 illustrates the nozzle receptacles 132 are conically widened end and have first a widened cylinder portion for receiving the sealing element 98 and a cylinder portion located inside with a smaller diameter, which holds the front conically tapered connecting piece 92 with little play and thus the deformation of the sealing element 98 after limited to the assembly.

The contact pins 96 pass through respective contact surface elements 134, which are formed by stamping and bending sheet metal and group within the terminal housing 6 a plurality of pins 96 of the same polarity, so that they are assigned to a heating stage are. This in FIG. 6 bottom contact surface element is a first plus pad element 134, whereas the upper contact surface element is a minus pad element 136. In particular FIG. 7 illustrates, the plastic housing member 10 receives another, second plus pad member 138. The minus pad member 136 and the plus pad members 134, 138 are separated from one another by a separator bar 140. This separating web 140 projects beyond a contact plane formed by the plastic housing element 10 for the contact surface elements 134, 136, 138. These surfaces of the plastic housing element 10 which predetermine this contact surface are in FIG. 6 designated by reference numeral 142. By the web 140, the leakage current path between the contact surface elements 134, 138 of the plus polarity and the contact surface element 136 of the negative polarity is extended, so that leakage currents between the two contacts are not to be feared. Also, the air gap between the contact surface elements 134 and 136 or 138 and 136 is laid. The contact surface elements 134, 136, 138 have between the contact pins 96 to the divider 140 opening semicircular recesses 143. In FIG. 6 In each case, contact tongues 144, 146 can be seen, which protrude through the printed circuit board 18 and are integrally formed by stamping and bending on the contact surface elements 134 and 136 and which are held raised in contact tongue holding regions 148 relative to the contact surfaces 142. The FIG. 8 lets see details in this way. As illustrated there, the respective contact surface elements 134, 136 have end-side connection tabs 145, which open into the contact tongues 144, 146. As continues from the FIGS. 6 and 8th As can be seen, the contact surface elements 134, 136, 138 for the individual contact pins 96 formed contact openings, which are made by punching and bending. Accordingly, opposing contact protrusions 150 are elastically stretched against the outer periphery of the contact pins 96. How to continue FIG. 8 As can be seen, the plastic housing element 10 forms locking projections 152 which are inserted into locking openings 154 of the contact surface elements 134, 136, 138, which are bounded on opposite sides by sharp-edged clamping segments 156 of the sheet material forming the contact surface elements 134, 136, 138. Accordingly, these clamping segments 156 dig into the locking protrusions 152 and secure the contact surface elements 134, 136, 138 after sliding onto the locking protrusions.

The FIG. 8 further shows the previously described heatsink 32, which are exposed within the plastic housing member 10 and project with a flat contact surface 158 the divider 140 on the upper side.

In the middle between the heat sinks 32 and at the edge of the plastic housing element 10 are each fixing eyes 160 for the previously already generally introduced pressure element 20 can be seen. How the particular FIGS. 4 and 9 To illustrate, this is honeycombed with a plurality of perpendicular honeycomb webs 162 formed.

The sectional view according to FIG. 9 illustrates the installation of the heat sink 32 in the plastic housing element 10. This has - like FIG. 8 can recognize - a plurality of distributed on the circumference of a raised Kühlkörpereinbringöffnung 164 of the plastic housing member 10 provided latching post 166 conically narrow the edge of the Kühlkörpereinbringöffnung 164 and form latching shoulders 168, which engage over a formed on the heat sink 32 circumferential locking bar 170 and thus form-fitting against pushing out prevent above and in the direction of the terminal housing 6. The contour of the recesses 143 of the contact surface elements 134, 136, 138 corresponds to the contour of the heat sink inlet opening 164, so that its raised edge is closely bounded by the contact surface elements 134, 136, 138. The two plus pad elements 134, 138 are identically shaped so that they can be selectively used to form the first or second pad elements 134 or 138. On the latching shoulder 168 opposite side of the latching web 170 is a sealing element 172, which surrounds the cooling body 32 circumferentially and on the latching web 170 facing away from the bottom in the circumferential direction by in FIG. 9 is not supported to be detected webs, so that the sealing element 72 can not slip in the direction of the power unit 2 by a designated by reference numeral 174 Abdichtaufnahme. This seal receiver 174 is integrally formed by the plastic case member 10 and extends the heat sink insertion hole 164.

In FIG. 9 the sealing element is shown in a slightly compressed configuration. Meanwhile, the seal member 172 is compressible in the longitudinal direction of the seal receiver 174 such that the seal between the inner peripheral surface of the cylindrical seal receiver 174 and the outer peripheral surface of the heat sink 32 is lost. The In this case, sealing element 172 can be compressed by approximately 2/10 to 7/10 mm in lengthwise direction of sealing seat 174 due to migration of detent web 170. The compensating movement is applied by screwing the pressure element 20 to the fastening eyes 160 after mounting the printed circuit board 18, which is provided on its the heat sink 32 facing bottom 176 with two semiconductor power switches 178. Each circuit breaker 178 is located on the flat contact surface 158 of the associated heat sink 32. At the level of the circuit breaker 178, the circuit board has a bore 180 which is penetrated by pressure webs 182 of the pressure element 20. These pressure bars 182 are directly against the circuit breaker 178 and press it against the heat sink 32. Since the circuit breaker 178 may have considerable thickness tolerances due to manufacturing, provided in the embodiment sealing element 172 allows compensation by retreating of the heat sink 32 in the direction of the power unit 2 without the sealing of the heat sink 32 in the plastic housing element 10 is lost. As can be seen from the overall view, in particular of FIGS. 4 and 9, the pressure element 20, after being screwed against the plastic housing element 10, acts on both power switches 176 and presses them against the heat sink 32 assigned to them, by means of a contact surface 158 of the heat sink 32 Insulating layer 184, however, the power switch 178 is electrically isolated from the associated heat sink 32. The insulating layer 174 is a ceramic insulating layer. Also, this insulating layer 184 extends beyond the heat sink 32 to increase the creepage significantly in the width direction (see. FIG. 9 ).

About the contact tongues 144, 146, the contact surface elements 134, 136 contacted with the circuit board 18. A second positive contact tongue 186 projecting from the second contact surface element 138 (cf. FIG. 4 ) connects the heating circuit formed by the second plus pad member 138 and the minus pad member 136 to the board 18 (see FIG. FIG. 4 ). As further FIG. 9 can recognize, contacts the semiconductor power switch 178 with the circuit board 18 and switches the power current to the associated circuit. In the present case, two heating stages are realized, which can be switched and controlled in each case via one of the semiconductor power switch 178.

Sealed heat sink

As previously described, the heat sink 32 is also sealed in the heat sink insertion opening 164. This shows the embodiment, specifically FIG. 9 , a situation in which the power switch 178 has the smallest thickness within the conceivable tolerance range. In this case, the locking webs 170 lie directly below the locking shoulders 168. However, a touch does not take place, so that the compression force caused by the slight compression of the sealing element 172 acts on the phase boundary between the heat sink 32 and the power switch 178. This power switch 178 is applied regardless of the thickness tolerance on the underside 176 against the printed circuit board 18. The pressure element 20 relieved with its pressure ribs 82 only the circuit board 18, so that the circuit breaker 178 is not clamped over the circuit board 18, but only between the pressure element 20 and the bias causing heat sink 32 with the interposition of the insulating layer 184.

Accordingly, the location of the power switch 178 and the circuit board 18 and the pressure element 20 does not change in a power switch 178 with greater strength. Rather, the heat sink 32 is urged in the Kühlkörpereinbringöffnung 164 in the direction of the power section 2, so that the sealing element 172 while maintaining the sealing of the heat sink 32 compressed more and - compared to the representation in FIG. 9 - The locking webs 170 in a further lowered position, ie further spaced from the locking shoulders 168 are arranged.

Defined contact points for the PTC element; Air and creepage distance

The embodiment of an electric heater shown in the figures has heat-generating elements which are designed in a special way in order to lengthen creepage distances and to reduce the risk of leakage current transmission. This particular design is described below with particular reference to FIGS Figures 2 and 11 clarified. So has - as in FIG. 2 each at least two 188 marked by reference numeral 188 defined projections 188 define within the receptacle 78 support points for each PTC element 80. These support points 188 prevents the PTC elements 80 directly to the receiving 78 predetermining smooth inner wall of the position frame 76 abut. Thus, the creepage distance of opposing surfaces of the PTC elements 80 is increased.

In particular FIG. 2 can recognize, the support points 188 are formed substantially pyramid-shaped and then have a tapered design. Furthermore, the surfaces of the support points 188 are like the sectional view according to FIG FIG. 11 clarified - concavely curved. The creepage distance is further increased by the curvature of the surface. The previously mentioned and provided between the contact plates 82 and the position frame circumferential gap 84 also contributes to increase the creepage distances.

Special EMC protection of the embodiment

Furthermore, the heat generating elements 66 are particularly EMC protected. Thus, the position frame 176 is basically completely surrounded by a shield, which are formed on the one hand by the sheet metal cover 110 of the position frame 76 and on the other hand by the sheet metal cover 70 of the corrugated fin elements 64. As FIG. 11 illustrates only a small edge-side gap between the various covers 70, 110 remains. Otherwise, the PTC elements 80 are completely enclosed by a metallic shield. Accordingly, the heat generating elements 66 can not emit substantial electromagnetic radiation.

All corrugated fin elements 64 are further connected to each other via integrally formed on the metal shell 8 locking elements, which are not shown in the drawing, however, may be formed as this, which goes back to the applicant EP 2 299 201 A1 describes the disclosure of which is incorporated in the disclosure of this application. It is only important that the metal shell 8 forms electrically connected projections that contact the corrugated fins 64 such that all corrugated fins 64 are electrically or indirectly connected directly to the metal shell 8 and grounded.

Tightness and tightness test

The embodiment discussed above has heat-generating elements 66 whose receptacle 78 is hermetically sealed from the environment, so that moisture and contamination can not reach the PTC elements 80. As a result, a high insulation of the PTC elements 80 is created because any charge carriers affect the isolation of the PTC elements 80, which can get into the receptacle 78 in the prior art, the insulation. Furthermore, with the present invention, all the heat-generating elements 66 are sealingly inserted into the terminal housing 6. Usually, to check the necessary tightness after the joining of the power unit 2 to the plastic housing member 10 at its free, usually closed by the housing cover 12 end a test bell is placed, which is sealingly applied to the free edge of the plastic housing element 10. About this test bell, the connected part of the electric heater is placed under increased hydrostatic pressure, for example, by compressed air. It maintains a certain level of pressure and checks whether it is reduced by possible leaks over time. If this is not the case, the component is rated as good.

Simplified installation

Accordingly, in the production of the embodiment shown, first the power part 2 is manufactured separately. First, the heat generating elements 66 are mounted. In this case, the sheet metal cover 110, the underside and thus in any case after gluing the sheet metal cover 110 associated insulating layer 90 closed on one side open position frame 76 on the underside, so that inserted from the other side of the PTC elements 80 and then the associated contact plate 82 are placed on this can finally hang up on the insulating layer 90 and seal over the adhesive edge 88 relative to the position frame 76. In particular, with reference to FIG. 11 described manner, the thus prepared heat-generating elements 66 are inserted into a frame member 48 of the frame 44, in each case alternately to the arrangement of corrugated fin elements 64. As is apparent in particular from FIG. 4 results are usually between two heat-generating elements 66 each two corrugated rib elements 64 at. In other words, a layer L of corrugated fin elements abuts on each side of a heat-generating element 66. The comparison between FIG. 4 and FIG. 11 further illustrates that in the embodiment according to FIG. 4 in a position at least two corrugated rib elements 64 are arranged.

After all elements of the layer structure 46 have been inserted into the frame member 48, the frame 44 is closed by placing and locking the other frame member 48. Thereafter, via the spring insertion openings 120, the respective spring elements 121 are inserted between the layer structure 46 and an outer edge of the receptacle 60 created by the frame 44. Finally, the spring elements 121 are braced against each other, as shown in the EP 2 298 582 is described. Thereafter, the thus prepared power part 2 is joined to the metal shell 8 and the plastic housing member 10. Due to their tapering configuration, the ramp surfaces 124 serve as positioning and centering aids, so that the holding element 126 can be effectively introduced into the positioning opening 127. The holding element 126 is usually leading relative to the contact pins 96, so that a coarse positioning is carried out only on the holding elements 126 and then the contact pins 96 are inserted into the cylindrical receiving socket 132.

Improved heat transfer

The FIGS. 12 to 15 illustrate a further aspect of the present invention, which is that in a layer L in the flow direction provided corrugated fin elements 64 in a direction transverse to the flow direction S, however, are provided in their respective installation plane within the layer structure 46 offset from each other. Accordingly, in the in FIG. 12 shown enlarged side view of a heating element 62, the meandering bent metal strip 68 of the successively provided in a layer L corrugated fin elements 64 recognizable. These are identified by reference numerals 68.1 and 68.2 and thus distinguishable. It can be seen that the air to be heated, which flows in at right angles to the plane of the drawing, flows against almost completely separate meandering bent metal strips 68.1 and 68.2. In particular, the rear sheet metal strip member is not shaded from the front. This results in a good heat transfer. In addition, the air flow S to be heated is redeployed during the transition from the first plane E1 to the second plane E2, which is accompanied by turbulent flow, which also improves the heat transfer.

The FIGS. 13 to 15 show a second embodiment according to the FIGS. 10 to 12 , The illustrated embodiment of a heating element only differs from the previously discussed embodiment, that in a position L1 and L2 three corrugated rib elements 64 are arranged one behind the other. Also in each case arranged in a plane E1, E2, E3 corrugated fin elements 64 are each strictly associated with a PTC element 80. As FIG. 15 clarifies, the air flowing through the heating element 62 is repeatedly redeployed. The labyrinth of metal strips 68.1, 68.2 and 68.3 formed by the meandering metal strips 68, which are offset relative to one another, leads to a very good heat transfer and power output.

Modular structure of the frame

FIG. 16 shows the previously described frame members 48 and a frame intermediate member 190 which is provided with female and male locking elements 50, 52 corresponding to the frame members 48, so that the frame intermediate member 190 can be easily locked between the frame members 48. The provided in the frame receptacle 60 for the layer structure 46 is thus increased by exactly the width that contributes to a plane of corrugated fins 46. In the in the FIGS. 10 to 15 shown embodiments of heating elements 62, the heat generating elements 66 are each formed uniformly, ie, whether two PTC elements 80 are arranged one behind the other in the flow direction S or three PTC elements 80; the PTC elements 80 are each received within a unitary position frame 76. However, the corrugated fin elements 64 are identical. An identical plastic housing element 10 can be used in each case for the heating elements 62 provided with three corrugated rib elements 64 arranged next to one another and the heating bars 62 provided with two corrugated rib elements 64. For also the intermediate frame member 190 has holding element parts 122 which cooperate with the holding element parts 122 of one of the frame elements 48 in order to form a complete holding element 126, via which also the widened frame 44 follows FIG. 16 can be connected to the plastic housing element 10. If, for example, four corrugated rib elements 64 form a heating element in succession in the direction of flow, then a second frame intermediate element 190 can be installed in the frame 44.

The Figures 17 and 18 show a comparison with the embodiment described above slightly modified embodiment. The same components are identified by the same reference numerals. In the in the Figures 17 and 18 In particular, the shielding housing element 8 described above is turned away.

Instead of a cup-shaped housing element accommodating the plastic housing element 10, a shielding contact plate 192 is provided, which rests positively against outer contact surfaces of the plastic housing element 10. This also forms bulges 194, in which shielding contact tongues 196 of the shielding contact plate 192 are accommodated. The Abschirmkontaktzungen 196 are each provided at the level of a heat generating element 66 and contact the edge 112 of this element 66. Further, the Abschirmkontaktblech 192 formed by punching and bending molded spring bars 198 which abut each of the heatsink 32 at the front and contact with this , In particular FIG. 18 As can be seen, the Abschirmkontaktblech 192 tightly surrounds the cylindrical nozzle receptacle 132 which is formed by the plastic housing element 10.

As further particularly from FIG. 18 can be seen, the points in the Figures 17 and 18 illustrated embodiment on a ground terminal pin 200. This connection bolt 200 is held, for example, by encapsulation in the plastic housing element 10. The verclipste with the plastic housing element 10 Abschirmkontaktblech 192 forms a formed by punching and bending bolt receptacle 202, which bears under elastic circumferential stress on the terminal bolt 200 electrically conductive.

This results in a complete shielding of all, involved in the current management elements of the embodiment. Furthermore, the heat sinks 32 are grounded via the shield contact plate 192, so that the reliable electrical isolation between the power switch 178 and the heat sink 32 can be checked by monitoring the ground potential at the terminal stud 200. Any defect in the electrical insulation may be detected and output to prevent the servicing potential from being electrocuted when servicing the electrical heater with insufficient electrical isolation.

LIST OF REFERENCE NUMBERS

2

power unit

4

control part

6

connection housing

8th

Shield / metal bowl

10

Plastic housing element

12

housing cover

14

female power connector housing

16

female control connector housing

18

circuit board

20

pressure element

22

Plus connector plug contact

24

Negative connection plug contact

26

Control contact element

28

Terminal stud / mass

30

cooling channel

32

heatsink

34

Air passage channel

36

Through opening

38

locking opening

40

locking lug

42

mounting hole

44

frame

46

Layer structure / heating block

48

frame element

50

male detent element

52

female locking element

54

Outside of the frame

56

opening

58

crossmember

60

accommodation space

62

heater

64

Corrugated fins element

66

Heat generating element

68

meandering curved sheet metal strip

70

metal cover

72

edge

74

free end of the corrugated fin element of the bent sheet metal strip

76

position frame

78

admission

80

PTC element

82

contact sheet

84

circumferential gap

86

sealing groove

88

adhesive edge

90

insulating

92

spigot

94

channel

96

pin

98

sealing element

100

female clip element recording

102

staggered lead

104

clips opening

106

clips opening

108

clips Steg

110

metal cover

112

edge

114

edge surface

116

test channel

118

Boundary region for the edge 112

120

Federeinbringöffnung

121

spring element

122

Support member section

124

ramp surface

126

retaining element

127

positioning

128

groove

130

drilling

132

cylindrical neck adapter

134

first plus contact surface element

136

Minus-contact surface element

138

second plus contact surface element

140

divider

142

Plant surfaces of the plant level

143

recess

144

first plus contact tongue

145

connecting straps

146

Minus contact tongue

148

Contact tongue retaining areas

150

contact projection

152

locking projection

154

locking opening

156

clamping segment

158

contact surface

160

fastening eye

162

honeycomb webs

164

Kühlkörpereinbringöffnung

166

latch post

168

locking shoulder

170

latching web

172

sealing element

174

sealing seat

176

bottom

178

breakers

180

drilling

182

pressure bar

184

insulating

186

second plus contact tongue

188

Projections / support points

190

Frame intermediate element

192

Abschirmkontaktblech

194

bulge

196

Abschirmkontaktzunge

198

spring bar

200

connecting bolt

202

bolt Hole

L

location

e

level

S

flow direction

Claims (13)

1. Heat generating element (6), particularly for an electrical heating device of a motor vehicle, with a positional frame (76), which forms a sealed receptacle (78) in which at least one PTC element (80) is accommodated, and contact plates (82) abutting on two oppositely situated sides of the PTC element (80),
   characterised in that
   the receptacle (78) is accessible through at least one inspection channel (116) that is accessible from the outside in order for checking the sealing of the heat generating element.
2. Heat generating element according to Claim 1, characterised in that the inspection channel (116) is surrounded by a connection piece (92) that protrudes from the positional frame (76).
3. Heat generating element according to Claim 1 or 2, characterised in that the connection piece (92) is surrounded by a sealing element (98).
4. Heat generating element according to one of the previous claims, characterised in that the connection piece (92) forms a channel (94) for a contact element (98) connected to one of the contact plates (82) in an electrically conducting manner.
5. Electrical heating device, particularly for a motor vehicle, having a frame (44), which forms on oppositely situated sides openings (56) for the passage of a medium that is to be heated, a layer structure (46) arranged in the frame (44) and comprising layers of corrugated-rib elements (64) and heat generating elements (66) according to claim 1 and a connecting housing (6) that accommodates electrical contact elements (82) of several heat generating elements (66),
   characterised by
   a sleeve receptacle (132) formed on the connecting housing (6) for the sealing accommodation of a connection piece (92) that protrudes from the heat generating element (66).
6. Electrical heating device according to Claim 5, characterised by a sealing element (98) that is made of an elastomeric material and that is arranged between the connection piece (132) and the sleeve receptacle (132).
7. Electrical heating device according to Claim 5 or 6, characterised in that a contact element (96), which protrudes from the connection piece (92) and which is electrically connected to the one of the contact plates (82), protrudes beyond the sleeve receptacle (132).
8. Electrical heating device according to one of the Claims 6 or 7, characterised in that for each heat generating element (66) two contact elements (96) lie exposed in the connecting housing (6) and are connected to contact surface elements (134, 136, 138), between which a partition ridge (140) is provided that protrudes beyond a contact base (142) for the contact surface elements (134, 136, 138).
9. Electrical heating device according to one of the Claims 5 to 8, characterised by a heat sink (32), onto which flows the medium to be heated, and a power switch (178) that is inserted into the connecting housing (6) in a sealed manner and that is connected in a thermally conducting manner to the heat sink (32).
10. Method for the manufacture of an electrical heating device, in which several heat generating elements (66) according to claim 1 are manufactured, characterised in that the heat generating elements (66) after being manufactured are built into a connecting housing (6) in a sealing manner and that the sealing of the heat generating elements (66) is checked prior or after the installation into the connecting housing (6) by applying an overpressure in the receptacle (78) by means of at least one inspection channel (116) that is accessible from the outside.
11. Method according to Claim 10, characterised in that the sealing is checked after the installation of the heat generating elements (66) into the connecting housing (6).
12. Method according to Claim 10 or 11, characterised in that the heat generating elements (66) are manufactured with an insulating layer (90) that covers the outside of the contact plates (82) and that is adhered in a sealed manner to the positional frame (76).
13. Method according to one of the Claims 8 to 12, characterised in that the contact plates (82) are clipped to the contact elements (96) that are introduced into the positional frame (76).

Images