EP1515587B1 - Electrical heated device with sealed heating element - Google Patents

Description

The invention relates to an electric heater, in particular as auxiliary heater for motor vehicles, a structural unit for such a heater and a corresponding manufacturing method.

For use in motor vehicles, especially motor vehicles with new consumption-optimized engines, in which a smaller amount of heat energy is generated, electrical booster heaters are used for heating of the interior and engine. However, such electrical heating devices are also suitable for other applications, for example in the field of domestic installations, in particular room air conditioning, in industrial plants and the like.

For an electric booster heater for a motor vehicle PTC heating elements are preferably used with radiator elements in thermally conductive connection. The heat generated by the PTC heating elements is released via the radiator elements to the air flowing through. The overall arrangement of a stacked structure of PTC heating elements, radiator elements and contact sheets, which serve the power supply, is held in a frame to increase the efficiency of the heating in a clamping pressure. By clamping a high electrical and thermal contact of the PTC heating elements is achieved.

The layered structure is held in a stable frame with preferably U-shaped cross-section. The frame is designed so that it compresses the layered structure. The clamping may alternatively be effected by spring elements arranged in the layered structure. So that the frame can absorb the spring forces, it is mechanically particularly stable, preferably formed with a U-shaped cross-section. Such a conventional heating device is known for example from DE-A-101 21 568.

The minimum height of the longitudinal members of such a frame with a U-shaped cross-section (or C-shaped cross section according to DE-A-101 21 568) is at the required clamping forces in about 11 mm. This results in the entire heater not usable for the air passage height of at least 22 mm. Such a design with external clamping or outside holding frame thus has a high surface area, which is not available for the air flow. For this reason, such electric heaters are not suitable for use at very low installation heights.

When assembling electrical heaters with external holding frame or clamping outside consuming measures are required, which counteract the hindering during assembly pressure forces of the springs / the frame.

Because of these disadvantages, heaters with a conventional support frame for modern air conditioning units, especially for installation in motor vehicles, are increasingly suitable. Air conditioning units for multi-zone air conditioning in a comfort-oriented motor vehicle increasingly require heaters of great length but low overall height.

In addition, conventional constructions with a holding frame, in particular made of metal, a high weight. For installation in motor vehicles, however, it is desirable in view of the total weight of the vehicle to be able to use electric booster heaters with a particularly low weight.

Another disadvantage of metal support frames is their conductive surface. In order to increase the safety in motor vehicles, metal surfaces are increasingly avoided, so that their contact is safely possible, i. without electrical or thermal line. For this purpose, the heating devices described above are preferably provided with a sheath made of plastic, as for example in the heater shown in DE-A-101 21 568.

Another disadvantage of conventional electric heaters is the risk of corrosion of contact sheets that power the heaters. The possibility of contact plates coming into contact with moisture exists both during the manufacturing process and during operation. Corrosion between a PTC heating element and a contact sheet made of, for example, aluminum may cause a power loss of up to about 30%.

From EP-A-1 182 908 it is known to fasten PTC heating elements to the contact sheets by means of a metal foil coated on both sides with adhesive.

The object of the invention is to provide an electric heater, an assembly for an electric heater and a manufacturing method for an electric heater, which has an improved structure, which does not have the above-mentioned disadvantages.

This object is achieved with the features of the independent claims.

According to the invention, in the manufacture of the electrical heating device, first of all one of the contact plates which contact the PTC heating element is provided with a lacquer layer. The PTC heating element is "provisionally" fixed and sealed on the contact plate via this lacquer layer.

Such a heater has several advantages. In particular, the lacquer layer additionally applied to the electrode brings about further corrosion protection than conventionally achievable. The varnish protects the contact plate and the connection between the PTC element and the contact plate against the ingress of moisture. A corrosion over Moisture, with which the contact plate comes into contact during manufacture or during operation, is thus excluded.

The lacquer layer is applied during the manufacturing process on the side of an electrode facing the PTC heating elements. Subsequently, the PTC heating elements are positioned on the lacquer layer. By caused by the spring element clamping pressure existing between the PTC element and the contact plate paint is largely pushed out. The pressed-out lacquer seals the gap between the PTC heating element and the contact plate via a bead. This sealing of the transition between the electrode and the PTC heating element enables efficient corrosion protection.

In addition, the invention enables a simplified production of such an electric heater. In the prefabricated units, the PTC heating elements are held above the paint at predetermined positions on the contact sheet. As a result, during the manufacturing process, an individual positioning of the individual elements, in particular the PTC elements, by hand or machine superfluous and the manufacturing process can be significantly shortened.

In addition, eliminates the need to use a positioning frame or positioning means, which keep the PTC heating elements spaced from each other. By prefixing the PTC heating elements via the paint, they are sufficiently firmly connected to one another for the production. The mechanical stability of the compound PTC heating element and contact plate only has to outlast the manufacturing process. Subsequently, the mechanical stability and fixation of the heating elements via the clamping pressure is effected, which is generated by the spring element. With prefabricated units can thus shorten the production process in a simple manner.

Preferably, the paint is an electrically non-conductive paint. In this way, the reliability of the heater is increased because exposed metal surfaces are avoided. At the same time corrosion of the surface of the contact plate is prevented. For this purpose, in particular a silicone varnish used. Not only is such a silicone varnish electrically non-conductive, but it is also capable of compensating for the different expansion coefficients of the PTC heating element and the contact sheet, which is preferably made of aluminum. It is therefore particularly advantageous to use an elastic paint.

According to a further advantageous embodiment, a highly viscous lacquer is used. The paint has a viscosity lower than 900 mPa.s. Such a coating can therefore be processed particularly easily, for example, a simple coating application by a brush or stripping coating, in particular by a drip coating on commercially available metering devices possible. In this way, the production of prefabricated units can be particularly simplified.

A further simplification of the production can be achieved in that the prefabricated units consist of a radiator element, a contact plate fastened thereto and the PTG heating elements fastened on the latter above the lacquer. With such a larger prefabricated unit, the production can be further simplified and accelerated.

According to a preferred embodiment, the contact plate, on which the PTC heating element is attached via the paint, made of aluminum. With this material, a particularly good heat transfer between the PTC heating element and the radiator element can be achieved.

Preferably, the elongated end faces are mechanically very stable and therefore can absorb very high forces. For this purpose, transverse struts are provided in openings of the elongated end faces for the air flowing through, which receive the clamping forces generated by the spring element. In this way, high clamping forces at low height and much lighter materials such as plastic are possible. With the structure according to the invention, electrical heating devices can be used more diversely, in particular even with only a small available structural height.

According to an advantageous embodiment of the invention, in addition to the cross struts in the openings of the housing sides longitudinal struts are provided so that the struts form a lattice structure. As a result, the struts themselves can be kept particularly thin, so that they impede the air flow only insignificantly and yet prevent bending of the housing effectively. A housing for an electric heater is thus produced in a simple manner from a lightweight and also easily processable material such as plastic.

So that the air flow of the air to be heated is not hindered by the lattice struts, in particular the longitudinal struts are arranged so that they are in the range of PTC heating elements. As a result, the longitudinal braces are placed so that they coincide sections where there is no air flow.

Preferably, the housing is made of plastic. An important advantage of a plastic housing is its low weight, its flexible formability and its low production costs. With this material, the cost of a heater can be kept very low.

According to an advantageous embodiment of the invention, the housing has a lateral opening for insertion of the spring element after assembly of the heater. As a result, the manufacture of such a heater is much easier, since no special devices for overcoming the spring forces during assembly are required. The spring is inserted into the housing only when the composite housing is able to absorb the forces generated by the spring when compressing the layered structure. Preferably, the spring is guided in a groove. By the subsequent insertion of the spring into the housing, without the housing itself must be opened to it, can be much lighter housing materials than conventional use, preferably plastic.

According to an advantageous embodiment, the housing is composed of two half-shells. As a result, a particularly simple assembly of the heater is possible. For this purpose, the half shells are designed to be plugged together. By the Use of locking pins or locking lugs, which cause a mating latching of the half shells when mating the half shells of the housing, a particularly fast assembly is possible.

Both half shells are preferably designed so that they separate the housing approximately centrally between the opposite, open housing sides. As a result, the housing is particularly stable on the open sides and only in the middle, i. At the dividing line of both half-shells, the housing can absorb little or no clamping forces.

In a particular embodiment, the two half shells are provided at their parting lines with additional projections and depressions which engage in mating together and interlock the half shells. The housing can thus absorb higher forces in the middle area, at the dividing lines of both half-shells. The projections and depressions entangle both half shells together and thereby cause an increase in the mechanical stability of the side surfaces. With such a construction, high clamping forces can be used even with housing materials with a fundamentally lower stability.

The spring element is designed such that it transmits the clamping forces substantially to the reinforced housing sides.

The spring element preferably consists of a sheet metal part with obliquely projecting spring segments. Preferably, the spring element is formed integrally with the spring segments. As a result, the spring can be produced for the first time as an endless part and fed in a simple manner from a roll to the production. Conventionally, however, each spring must be made separately and manufactured individually for different lengths. By contrast, the spring element of the heating device according to the invention can be easily cut to size from a roll to any desired length, so that costly individual production processes for the spring and adaptations of the production process are avoided in the event of changes to the structure of the heating element.

Due to the separation of housing and spring, the thickness of the springs can be reduced from conventionally about 0.8 mm according to the new design principle to a thickness of about 0.3 mm. As a result, the spring can be produced with little effort, without the efficiency of the heater is reduced.

In order to achieve a high efficiency of the electric heater, a spring segment is provided for each position of a PTC heating element, so that by an individual clamping of each PTC heating element, the efficiency is improved.

A particularly high efficiency can be achieved by increasing the clamping forces when a plurality of spring segments is provided in the region of a PTC heating element, preferably two or three individual spring segments. This keeps each PTC heater clamped along its entire length.

According to a further preferred embodiment, the springs consist of a metal sheet, from which obliquely individual spring segments protrude in the transverse direction, which reinforce the spring mechanically so that a deflection about the longitudinal axis of the spring is not possible. For this purpose, the spring segments each extend into the edge region of the spring, so that the spring can be supported on the stable outer edge of the housing. The housing must therefore absorb forces only at its edges and may be made less stable in the middle. In this way, a particularly lightweight and easy to use housing material can be used.

According to a particular refinement of the electrical heating device, a seal is provided between the longitudinal struts and the layered structure. Such a seal, in particular as a silicone seal, is preferably formed in one piece and seals the entire grid structure.

Further advantageous embodiments of the invention are the subject of the dependent claims.

Fig. 1

eine schematische Darstellung des Aufbringens einer Lackschicht auf einem Kontaktblech,

Fig. 2

eine schematische Darstellung des Aufsetzen eines PTC-Heizelementes auf die Lackschicht des Kontaktblechs,

Fig. 3

eine schematische Darstellung einer vorfabrizierten Baueinheit aus einem auf einem Kontaktblech fixierten PTC-Heizelement,

Fig. 4

eine alternative Ausführungsform einer vorfabrizierten Baueinheit, die in Ergänzung zu den Elementen der Fig. 3 ein Radiatorelement umfasst,

Fig. 5

eine schematische Darstellung eines Ausschnitts einer erfindungsgemäßen Heizvorrichtung mit einer in diese eingesetzte, vorfabrizierte Baueinheit gemäß Fig. 4,

Fig. 6

eine schematische Ansicht eines inneren Aufbaus einer erfindungsgemäßen Heizvorrichtung,

Fig. 7a

ein schematische Schnittansicht durch eine erfindungsgemäße Baueinheit aus einem Radiatorelement, einem über eine Lackschicht versiegelten Kontaktblech und ein auf dem Kontaktblech angeordneten PTC-Heizelement,

Fig. 7b

eine perspektivische Ansicht einer Baueinheit gemäß Fig. 7a,

Fig. 8

eine schematische Schnittansicht durch eine erfindungsgemäße Heizvorrichtung mit einem Kunststoffgehäuse und in diesem in mehreren Schichten angeordneten PTC-Heizelementen, Kontaktblechen und Radiatorelementen,

Fig. 9

eine aufgeschnittene, perspektivische Ansicht einer erfindungsgemäßen elektrischen Heizvorrichtung gemäß Fig. 8, wobei jedoch nur eine Halbschale des Gehäuses dargestellt ist,

Fig. 10

eine Aufsicht auf die erfindungsgemäße Heizvorrichtung gemäß Fig. 9 mit den in einer Halbschale angeordneten Radiatorelementen, Kontaktblechen und PTC-Heizelementen,

Fig. 11

eine Ansicht eines geschichteten Aufbaus aus Radiatorelementen, Kontaktblechen und PTC-Heizelementen, wie er im Gehäuse einer erfindungsgemäßen elektrischen Heizvorrichtung angeordnet ist,

Fig. 12

eine perspektivische Ansicht einer Halbschale des Gehäuses der elektrischen Heizvorrichtung der Erfindung, die nur zum Teil bestückt ist,

Fig. 13

eine perspektivische Ansicht einer Halbschale des Gehäuses der elektrischen Heizvorrichtung gemäß Fig. 12, die vollständig bestückt ist,

Fig. 14

eine perspektivische Ansicht des zusammengesetzten Gehäuses der elektrischen Heizvorrichtung,

Fig. 15

eine perspektivische Ansicht der elektrischen Heizvorrichtung gemäß Fig. 14, bei der das Federelement teilweise eingeschoben ist,

Fig. 16

eine perspektivische Ansicht einer anderen Ausführungsform des Gehäuses der erfindungsgemäßen Heizvorrichtung,

Fig. 17

eine weitere perspektivische Ansicht der Ausführungsform nach Fig. 16, bei der die Gehäuseseite, an der die Kontaktstifte vorgesehen sind, beispielhaft an eine spezielle Steckergeometrie angepasst ist,

Fig. 18

eine weitere Detailansicht der Ausführungsform des Gehäuses der erfindungsgemäßen Heizvorrichtung nach Fig. 16,

Fig. 19

eine perspektivische Ansicht einer schematischen Darstellung einer weiteren Ausführungsform der erfindungsgemäßen Heizvorrichtung während des Zusammenbaus,

Fig. 20

eine perspektivische Ansicht der zusammengesetzten Ausführungsform nach Fig. 19,

Fig. 21

eine Detailansicht der Innenseite einer Gehäusehalbschale einer weiteren Ausführungsform der Erfindung,

Fig. 22

eine Schnittansicht durch die zusammengesetzten Halbschalen des Gehäuses der Ausführungsform nach Fig. 21,

Fig. 23

eine vergrößerte Ansicht eines Details der Gehäusedarstellung aus Fig. 22, bei dem die Einzelheiten des verschränkten Aufbaus der Gehäuseseiten für eine stärkere mechanische Belastbarkeit der Gehäuselängsseiten deutlich erkennbar ist,

Fig. 24

eine schematische Darstellungen einer Aufsicht auf das erfindungsgemäße Federelement,

Fig. 25

eine schematische Darstellungen einer Seitenansicht auf das erfindungsgemäße Federelement,

Fig. 26

eine schematische Darstellungen einer perspektivischen Ansicht des erfindungsgemäßen Federelementes,

Fig. 27a

eine Ansicht eines Wellrippenelements mit einem an diesem befestigten Kontaktblech und

Fig. 27b

eine Ansicht einer weiteren Ausgestaltung des Federelementes.

In the following, the present invention will be explained with reference to preferred embodiments in conjunction with the accompanying drawings. The drawings show in detail:

Fig. 1

a schematic representation of the application of a paint layer on a contact plate,

Fig. 2

a schematic representation of the placement of a PTC heating element on the lacquer layer of the contact sheet,

Fig. 3

2 a schematic representation of a prefabricated structural unit made of a PTC heating element fixed on a contact plate,

Fig. 4

an alternative embodiment of a prefabricated structural unit, which comprises a radiator element in addition to the elements of FIG. 3,

Fig. 5

1 is a schematic representation of a detail of a heating device according to the invention with a prefabricated structural unit according to FIG. 4 inserted therein;

Fig. 6

a schematic view of an internal structure of a heating device according to the invention,

Fig. 7a

FIG. 2 shows a schematic sectional view through an assembly according to the invention comprising a radiator element, a contact plate sealed via a lacquer layer and a PTC heating element arranged on the contact plate, FIG.

Fig. 7b

a perspective view of a structural unit according to FIG. 7a,

Fig. 8

FIG. 2 a schematic sectional view through a heating device according to the invention with a plastic housing and in this PTC heating elements, contact plates and radiator elements arranged in several layers, FIG.

Fig. 9

8 is a cutaway, perspective view of an electric heater according to the invention, but only a half shell of the housing is shown,

Fig. 10

9 shows a plan view of the heating device according to the invention according to FIG. 9 with the radiator elements, contact plates and PTC heating elements arranged in a half shell, FIG.

Fig. 11

a view of a layered structure of radiator elements, contact plates and PTC heating elements, as it is arranged in the housing of an electric heating device according to the invention,

Fig. 12

a perspective view of a half-shell of the housing of the electric heater of the invention, which is only partially equipped,

Fig. 13

a perspective view of a half-shell of the housing of the electric heater of FIG. 12, which is fully populated,

Fig. 14

a perspective view of the assembled housing of the electric heater,

Fig. 15

a perspective view of the electric heater of FIG. 14, in which the spring element is partially inserted,

Fig. 16

a perspective view of another embodiment of the housing of the heating device according to the invention,

Fig. 17

16 is a further perspective view of the embodiment according to FIG. 16, in which the housing side on which the contact pins are provided is adapted, for example, to a specific plug geometry,

Fig. 18

a further detail view of the embodiment of the housing of the heating device according to the invention of FIG. 16,

Fig. 19

a perspective view of a schematic representation of another embodiment of the heating device according to the invention during assembly,

Fig. 20

a perspective view of the assembled embodiment of FIG. 19,

Fig. 21

a detailed view of the inside of a housing half shell of a further embodiment of the invention,

Fig. 22

a sectional view through the composite half-shells of the housing of the embodiment of FIG. 21,

Fig. 23

an enlarged view of a detail of the housing illustration of FIG. 22, in which the details of the entangled structure of the housing sides for a stronger mechanical load capacity of the housing longitudinal sides is clearly visible,

Fig. 24

a schematic representations of a plan view of the spring element according to the invention,

Fig. 25

a schematic representation of a side view of the spring element according to the invention,

Fig. 26

a schematic representations of a perspective view of the spring element according to the invention,

Fig. 27a

a view of a corrugated fin element with a contact plate attached thereto and

Fig. 27b

a view of a further embodiment of the spring element.

While in conventional electric heaters, the PTC heating elements are positioned by means of positioning, such as a positioning frame between contact plates, electrical heaters are produced according to the invention so that at least one of the contact plates is provided with a lacquer layer and on this the PTC heating elements prior to assembly in the electric heater can be positioned. These manufacturing steps are shown in FIGS. 1 to 3 in an illustrative manner.

Fig. 1 shows schematically the side view of a contact plate 2, which is provided with a coating layer 3 on the side facing the PTC heating element later. The PTC heating element 4 is then placed on this lacquer layer 3 (FIG. 2). The contact plate 2 with the lacquer layer 3 and the PTC heating element 4 arranged thereon form a prefabricated structural unit 1, which is shown schematically in FIG. 3.

The strength of the fixation of PTC heating elements 4 via the varnish 3 on the contact sheet is designed so that it sufficiently withstands mechanical stresses which occur up to and during the production of an electrical heating device. Stronger mechanical stress does not withstand this fixation. About such a coating layer 3, on which the PTC heating elements 4 are placed, the production of electrical heating devices can be significantly simplified. In particular, the number of parts to be assembled can be reduced by way of the prefabricated structural units 1 produced in this way become. In addition, the assembly is simplified because no tedious positioning of the individual elements in a housing is required. In addition, no positioning means are required because the PTC heating elements are held in position during insertion.

A particular advantage achieved by the paint is improved moisture protection. The achievable during assembly of the heater additional sealing of the connection PTC heating element 4 and contact plate 2 will be described below with reference to FIG. 5.

A variant of a prefabricated unit is shown in Fig. 4. On the contact plate 2, a radiator element 5 is additionally attached. This prefabricated structural unit, in which a PTC heating element 4 according to the manufacturing process illustrated in FIGS. 1 to 3 is fastened on the contact plate 2, allows a further reduction of the assembly steps required in the manufacture of an electrical heating device, since a separate insertion of the radiator elements 5 is dispensed with ,

According to a further embodiment, further elements of the heating device can subsequently be integrated into the prefabricated component to the radiator element 5. With each additional element of the prefabricated assembly, the number of manufacturing steps required in the fabrication of the heater decreases.

When installing the prefabricated structural unit 1 according to the invention (as shown in FIG. 4) into a housing of the heating device, the individual elements of the heating device are held in place after insertion of a spring element (not shown in FIGS. 1 to 8) via a clamping pressure. A section of an electrical heating device according to the invention, which illustrates the clamping pressure and its effect, is shown in FIG.

5 shows, in addition to the prefabricated structural unit 1 from FIG. 4, radiator element 5, contact plate 2, lacquer layer 3 and PTC heating element 4, a contact plate 10 adjoining the PTC heating element 4 and a further adjacent thereto Radiator element 11. The contact pressure caused by the clamping pressure is symbolized by black arrows in FIG. The contact pressure causes the paint 3 located between the PTC heating element 4 and the contact sheet 2 to be pressed out on the sides of the interspace 13 between the PTC heating element 4 and the contact sheet 2. The extruded from the gap 13 paint forms at the outer edges of the gap 13 Lackwülste 12, which seal the gap 13 against moisture penetration.

The heating device according to the invention is protected over the coating of the contact sheet with a lacquer layer and the sealing of the contact point PTC heating element and contact sheet caused thereby in an efficient manner against moisture damage, in particular corrosion, and a concomitant loss of performance. The heating device according to the invention is thus particularly suitable for extreme operating conditions, in which the risk is particularly great that the heater comes into contact with moisture ... activity.

Preferably, an electrically non-conductive paint is used for the paint 3. By taking place during the manufacturing process pressing the components of the heater, the paint is pressed out of the gap 13 and thus realizes an electrically conductive contact between the contact plate 2 and the PTC heating element 4th

The thickness of the coating application is preferably in the range between 10 and 20 μl / cm ² , particularly preferably in the range of 14 μl / cm ² .

The paint 3 can be applied in a simple manner by a brush, stripping or drip coating. This coating is made possible by a particularly high viscosity, which is preferably in the range of 900 mPa.s to 750 mPa.s. Particularly preferably, the paint has a viscosity of about 850 mPa.s. The paint forms a durable coating to protect against moisture and atmospheric contaminants.

When applying the paint over a drip coating this is applied dropwise via a commercially available metering device. The metering device is preferably a Dosiemadel.

For this purpose, a high-viscosity paint is to be used. In this case, a paint is used to increase the environmental impact, which has only a low proportion of solvents.

According to a preferred embodiment, the contact plate 2 is made of aluminum. Aluminum enables a particularly good advertising transition between the PTC heating element 4 and the radiator element 5.

Preferably, the contact plate 10, which contacts the PTC heating element 4 on the opposite side of the contact plate 2, made of brass, preferably tin-plated brass.

Fig. 6 shows schematically a preferred embodiment for the clamped held components of the heating device according to the invention. The structure comprises two prefabricated units 1, each having at least one PTC heating element 4, a contact plate 2 and a radiator element 5. In addition, the structure comprises further contact plates 20, 21, which abut the opposite sides of the PTC heating elements 4, and a final radiator element 22. The two contact plates 20 and 21 are at different potential. In addition, the lower radiator element 5 shown in Fig. 6 is connected to a plus potential power supply.

Overall, the internal structure of an advantageous embodiment of the heating element according to the invention shown in Fig. 6 comprises only five components to be mounted, namely two prefabricated units 1, two contact plates 20, 21 and an additional radiator element 22. Such a layered structure is thus particularly simple and quick to produce ,

A perspective view and a sectional view of a preassembled unit 30 are shown schematically in FIGS. 7a and 7b. The assembly 30 consists of a radiator element 35 which is connected to a contact plate 32. On the contact plate 32, a paint layer 33 is applied, via which the PTC heating elements 31 are fixed on the contact plate 32.

In Fig. 7a is a sectional view of the assembly 30 is shown, which is mounted in a heater under a clamping voltage. As a result of the clamping pressure, the varnish 33 located between the PTC heating element 31 and the contact plate 32 is pressed laterally out of the intermediate space, so that it seals or seals the interspace via beads 34, the so-called adhesive meniscus, against the ingress of moisture and contaminants.

In contrast to conventional electric heating devices for use in motor vehicles, the heating device according to the invention is constructed from two plastic half-shells. In production, a housing half can first be fitted in a simple manner and then the housing is completed by placing the second housing half. The assembly of the electric heater will be described below with reference to FIGS. 12 to 15.

FIGS. 8 to 10 show various views of a multilayer electric heating device according to an embodiment of the present invention. A sectional view through the electric heater is shown in Fig. 8, while Fig. 9 is a perspective view and Fig. 10 is a plan view of the arranged in a half-shell of the housing components of the heater. The housing consists of two interlocking half-shells 40a and 40b. In these half-shells, the structural units according to the invention are arranged from a radiator element 44, a contact plate 42 connected thereto and heating elements 41 fixed on the contact plate. The units are each separated by spacers 43 in one of the half-shells 40a, 40b used.

In each housing half-shell 40a, 40b reinforcing elements are provided for reinforcing the narrow housing longitudinal sides. In particular, latching tabs 46, 47 engage with one another when the two housing halves 40a, 40b are plugged together. In this way, the narrow housing longitudinal sides are mechanically reinforced and therefore can absorb higher clamping forces. Details and alternatives for a mechanically reinforced design of the narrow housing longitudinal sides are explained with reference to the following figures.

The clamping pressure is generated via a spring element 49, which compresses the layered structure of PTC elements 41, contact plates 42 and radiator elements 44, so that the electrical and thermal transition between the contact plates 42 and the PTC heating elements 41 is improved. This can increase the efficiency of the heater.

The PTC heating elements 41 are prepositioned on first contact plates 42 via a lacquer. On the opposite sides of the PTC heating elements 41, a further contact plate is provided during assembly. One of the two contacting a PTC heating element contact plates, as shown in Fig. 10, led out to the electrical power supply from the housing 40. Through the contact tabs 50 of the led out contact plates of the electric heater during operation power is supplied. For easier installation and secure positioning of the projecting out of the housing contact plates 50, these are held in each case via positioning aids 49 on the sides of the housing.

The layered structure of a plurality of assemblies inserted into the housing 40 is shown in FIG.

FIGS. 12 to 15 show successive stages of the assembly of the heating device according to the invention, which illustrate the structure of the heating device according to the invention. Fig. 12 shows a perspective view of a half-shell 62a of the half-shells 62a, 62b of the housing. In the half-shell 62a, a contact plate 66, a radiator element 64 and adjacent thereto PTC heating elements 4 are used. To make things easier of the assembly guide rails or positioning means are provided for all components. In particular, the position of the contact plate 66 is defined with the contact pin 66a when inserted via the guide 66b (or 67b for the contact plate 67 in Fig. 13). The radiator elements 64 are preferably designed in the form of corrugated rib elements. On one side, the corrugated fin element is provided with a contact plate. For the ends of the contact plate of the corrugated fin element 64 guides 64a are laterally provided in the inside of the housing. These guides are used only to facilitate assembly. In an alternative embodiment, they can therefore be dispensed with.

As shown in FIG. 13, a radiator element 64 and a contact plate 67 with a plug contact 67a are again provided above the PTC heating elements 4, corresponding to the construction shown in FIG. The second housing half-shell 62b can be plugged onto the first half-shell 62a so equipped. Both housing half-shells are preferably formed so that their parting line approximately in the middle between the two elongated housing end faces (having the passage openings) extends.

The assembly of the housing can be simplified in particular by the fact that both half-shells 62a, 62b are provided with latching pins 78 and corresponding bores 79 in the respectively opposite half-shell. When plugging together lock both half-shells as soon as the second half-shell 62b is completely attached to the first half-shell 62a.

The composite housing of the electric heater is shown in Fig. 14 again. In Fig. 14 it can be seen that each of the housing halves 62a, 62b has openings for the air flowing through at the elongated end faces.

In order to increase the efficiency of the heat generation by the PTC heating elements, they are kept clamped within the housing described in connection with FIG. 12 and FIG. 13 layered structure. This clamping is effected by an additional spring element 72. Preferably, the spring element is inserted at least between a housing inner side and the layered structure. In addition, such a spring element can also be inserted between the opposite housing inner side and the layered structure or at a location within the layered structure.

In order for the housing to be able to absorb the clamping forces without deformation of the housing, the elongated housing end sides are mechanically reinforced. Between the mechanically reinforced Gehäusestimseiten, especially in the region of the dividing line, the housing is not able to absorb high clamping forces.

In order to accommodate very high clamping forces, transverse struts 69 are provided within the lateral opening for the air to be heated. These cross braces allow the housing to accommodate sufficiently high clamping forces without deflection or deformation of the housing. The half-shells with the struts are each formed in one piece and preferably made of plastic.

In a particularly advantageous embodiment, the cross struts 69 are supplemented by one or more longitudinal struts 70, so that the struts 69 and 70 have the shape of a grid structure. Such a grid structure allows the cross braces 69 to be kept particularly thin and not obstruct the air flow. At the same time effectively prevents bending of the housing.

The stability of the housing between the mechanically reinforced Gehäusestimseiten is reinforced in an advantageous embodiment by a special design of the upper and lower sides of the half-shells. For this purpose, protrusions 76 and depressions 77 are provided on the upper and lower surfaces of each half shell 62a, 62b, which are arranged so that they engage in one another when plugged together. In this way, the mechanical stability of the upper and lower sides is increased by entanglement of the sides of the two half shells and between the mechanically reinforced elongated Gehäusestimseiten.

Since the housing is only after assembly in a position to accommodate high clamping forces without deformation of the housing, the spring element 72 can be used only after assembly of the housing. For this purpose, the housing 62 has an opening 71 on one side of the housing. Such an opening is preferably provided on the narrow sides of the housing 62. Each housing half 62a, 62b has corresponding recesses which complement each other in the assembled housing 62 to the slot 71 for insertion of the spring element 72. A particular embodiment of the inner sides of the housing to form a spring channel for insertion of the spring element 72 is described below with reference to Figures 21 to 23.

The positioning means 64a, 66b, 67b provided in the housing are arranged so that the pre-positioned elements of the heating device leave sufficient space for the spring element. In particular, the prepositioned elements are fixed in the clamping direction effected by the spring with play in order to keep them movable and to absorb the clamping pressure generated by the spring.

In Fig. 15 it can be seen that the spring element 72 has a plurality of individual spring segments which generate the clamping pressure. Preferred embodiments of the spring element 72 will be discussed below in conjunction with FIGS. 26a, 26b and 26c.

In the illustrated embodiments, the contact plates 66 and 67 are each disposed on the outside of the layered structure so that power is supplied to the PTC heating elements 74 via the radiator elements 64. This structure leads to a particularly good heat transfer between the PTC heating elements 4 and the radiator elements 64, which deliver the heat to the air flowing through, and heat conduction losses are therefore particularly low.

The arrangement of the contact plates at the top and bottom of the layered structure of the elements of the heater, the air flow is particularly little with special needs. As a result, the height can be kept small without reducing the air passage volume.

Due to the inventive design of the housing with mechanically particularly pronounced elongated Gehäusestimseiten the clamping forces are not received as conventional from the side rails of the support frame. The narrow sides of the housing can therefore be designed as desired. Preferably, the housing narrow sides are designed so that they allow a mechanical fixation and electrical contacting of the heater. For electrical contacting at least one narrow side of the housing is arbitrarily adaptable to the geometry of a plug for power supply.

The design of the narrow sides is shown by way of example in FIGS. 12 to 15. On the left side of the housing, a plug shape is formed from the respectively formed on both housing halves projections 73 a, 73 b. In this plug, the connector tabs 66a and 67a of the two contact plates 66, 67 protrude. On the opposite side, a plug 74 is formed from the projections 64a, 64b, which essentially serves for the mechanical fastening of the electric heating device. Since the narrow sides of the housing 62 do not absorb high forces, they can be arbitrarily designed for mechanical and / or electrical attachment.

FIGS. 16 to 18 show a further embodiment of a housing and a corresponding electrical heating device. FIG. 16 shows a perspective view of an embodiment of an electric heating device 80, which is narrower in comparison to the embodiment of FIGS. 12 to 15, but with a larger cross-sectional area for a higher air throughput. For this purpose, the heating device has PTC heating elements 4 in a plurality of planes in the layered structure. In contrast to the embodiment of FIGS. 12 to 15, the PTC heating elements 4, which have a rectangular shape, are aligned with their longitudinal sides parallel to the elongate housing end sides of the heating device.

Corresponding to each layer with PTC heating elements 4 in the layered construction of radiator elements 64, PTC heating elements 4 and electrode plates 81, 82 4 longitudinal struts 70 are respectively provided at the height of the layers with PTC heating elements. In the illustrated embodiment, a total of four layers with PTC heating elements 4 are present and, accordingly, four longitudinal struts 70 are provided. Due to the greater longitudinal extent of the heating device in comparison to the heating device of FIGS. 12 to 15, this embodiment also has a larger number of transverse struts 69.

In contrast to the first embodiment of Figures 12 to 15, two spring elements 72 are used in the heater shown, which are respectively inserted at the upper and lower end on the narrow side of the housing. The springs are each inserted so that the spring segments 86, which protrude from the spring element 72, project from the housing surface in the direction of the layered structure. Although not shown, other spring elements 72 can be inserted between the two illustrated spring positions in the layered structure.

Due to the majority of the layers with PTC heating elements 4 shown in this embodiment, a correspondingly higher number of contact plates is required. The uppermost and lowermost of the contact sheets 82 are respectively disposed adjacent to the upper and lower inner sides of the housing. The three middle contact sheets are each disposed adjacent to the three lower layers with PTC heating elements, i. corresponding to the three lower of the longitudinal struts 70th

Each of the contact sheets 81, 82 has protruding tabs 81a, 82a from the frame. The housing side 83, from which the contact tongues 81a, 82a protrude, can be configured as desired. A particular embodiment is shown in FIG. 17. On the housing 83 shown in FIG. 16, in each case an individually adapted plug form 85 is plugged or glued. This glued plug form can be adapted to the particular needs, for example for installation of the heater in vehicles of various vehicle manufacturers, the different types of plug contacts use. In the embodiment shown in Fig. 17, the attachable plug attachment 85 consists of a mechanical stop with Befestigungslöchem and a plug shoe 85a, in which the contact tongues 81a, 82a are arranged.

Preferably, transverse struts 69 of the grid structure are arranged at a distance of 30 to 40 mm. At a distance of the cross braces, which is greater than 40 mm, in particular from about 60 mm distance, the clamping forces can not be absorbed by the cross braces sufficiently. Below a distance of the cross struts of less than 30 mm, in particular less than 20 mm, on the other hand, these significantly hinder the air flow through the elongated ends of the heaters.

Figures 21 to 23 show a particular embodiment for the design of the insides of the two housing halves. The inner structure of the housing half-shells has a spring channel into which the spring 72 can be inserted after assembly of the two half-shells of the housing. The spring channel causes a guide of the spring during insertion, via each laterally extending grooves. The grooves are formed, for example, by the projections 94 and either the housing top or, as in the illustrated embodiment, via latch tabs 92a, 92b.

The projection 94 not only forms one side of the spring channel for inserting the spring, but also serves as a positioning aid of the elements of the heater. These are (pre-) fixed by the projection 94 with play in the housing to a insertion channel for the inserted after assembly spring.

The embodiment shown in Figures 21 to 23 also has an increased rigidity. Such additional stiffening may be required, inter alia, for the following reasons. In order to achieve high efficiency even with "large area heaters", ie heaters that are narrow but large area designed for high air flow, very high clamping forces are required. At housing temperatures of about 170 degrees Celsius, however, the stiffness of the plastic used decreases. In addition, the springs can not force only on the Transmitted edge of the housing, since the spring segments used have a minimum distance of about 2 mm to 2.5 mm to the edge of the spring. In order nevertheless to avoid a deflection of the upper and lower sides of the housing, these are preferably additionally stiffened. For this purpose, in each case two opposing arranged latching tabs 92a, 92b are provided in two housing halves. The latching tabs each protrude in the direction of the opposite half of the housing and are latched together via locking lugs 91 during assembly. This toothing on the upper and lower sides of the housing increases their mechanical rigidity and prevents bending.

A further increase in rigidity can be achieved via an additional side wall 95, 96. This side wall 95, 96 is respectively arranged above the previous side walls and connected via support members 93 thereto. In this way, the mechanical rigidity of the upper and lower sides can be increased so that the housing can accommodate very high clamping forces. As a result, a "large-area construction" is possible, ie a heating device with a plurality of layers of PTC elements stacked on top of each other and radiator elements lying between them.

The structure of the spring member 72 will be described below with reference to FIGS. 24, 25 and 26. FIG. 24 shows a plan view of the spring element 72, FIG. 25 shows a side view, and FIG. 26 shows a perspective view of the spring element 72.

The spring element 72 consists of a sheet metal part 85 and of this protruding spring segments 86. Preferably, the spring element 72 is integrally formed, wherein the spring segments are punched out on three sides of the sheet metal part 85 and bent about an axis 89 in the transverse direction of the sheet metal part 85. The angle α, by which the punched-out segments are bent, is approximately between 5 ° and 30 °, preferably between 15 ° and 20 °. By this structure of the spring element 72 no deflection in the transverse direction is possible, but only in the longitudinal direction. As a result, the spring element acts only on the edge of the housing, on which it is supported when generating the clamping force. Thus, the spring interacts ideally with the housing, the due to its structure can accommodate greater forces only in the housing sides and in the middle, in the region of the dividing line, less resilient. Preferably, the lateral ends of the spring segments are arranged very close to the edge of the spring element.

The illustration in FIGS. 24, 25 and 26 is merely schematic. The spring segments 86 need not be rectangular, but may also include areas of different width and inclination. For example, each spring segment may have a wider end portion that is slightly flattened to allow for better insertion of the spring element into the housing.

In Fig. 27a, a radiator element 64 and a contact plate 66 connected thereto are shown in an elongated embodiment for a "large area heater" (eg, as shown in Fig. 20). The corresponding spring element is shown in Fig. 27b. The spring element has a multiplicity of spring segments 86 arranged one behind the other. Each of the spring segments 86 is capable of exerting a pressing force of about 15 N. To increase the pressure force, the spring segments according to FIG. 27b are positioned closely one behind the other, so that two or three spring segments 86 are arranged over the surface of a PTC element. As a result, the clamping pressure can be doubled or even tripled. The clamping pressure is applied uniformly over the entire length of the spring in contrast to conventional frame mounts.

In order for the clamping forces generated by the spring segments 86 can be absorbed by the housing, the elongated Gehäusestimseiten are equipped with cross braces 69, that between two successive transverse struts 69 two to a maximum of five spring segments 86 are arranged.

The embodiment according to FIG. 15 shows a spring element 72 with two or more spring segments arranged next to one another. This embodiment is advantageous in housing shapes having a large depth.

While conventionally springs with a thickness of about 0.8 mm are used, spring elements with a thickness of 0.2 to 0.5 mm, preferably about 0.3 mm can be used in the new design principle. As a result, a spring action of the spring segments 86 can be achieved even with a small length of a spring segment.

A particular advantage of the heating device according to the invention is that the spring element can be produced for the first time as an endless part and thus can be supplied by a roller during production. Conventionally, each spring segment is manufactured separately and manufactured individually for all different heater lengths. In addition, it is sufficient to provide only one spring element per heater.

In addition to the low height is a particular advantage of the heating device according to the invention, that it can be produced in a particularly simple manner. The assembly of the heating device takes place as described in connection with FIGS. 12 to 15. According to the assembly of the individual elements takes place in contrast to conventional heaters without the clamping forces acting on the layered structure. Only after assembly of the housing, the spring is inserted into the composite housing (see Fig .. 15).

In summary, the invention relates to a new design principle for electric heaters, in which the functions of the frame and spring are separated. As a frame for an electric heater, a housing is used, which consists of two half-shells. Positioning aids for the PTC heating elements are arranged in the housing. The longitudinal sides of the housing are designed to be substantially open in order to allow an air flow through the heating coil.

Before mounting the heater, the PTC heating elements are attached via a paint on a contact plate contacting the PTC heating elements. The so prefabricated units facilitate assembly and avoid additional positioning means for the correct position of the PTC heating elements during manufacture.

The paint also provided protection against the ingress of moisture. In this way, at the same time effective corrosion protection is achieved.

In addition, a spring is inserted in the housing, which compresses the layered structure of radiator elements, PTC heating elements and contact plates. The spring can be inserted laterally into the housing by means of an opening provided laterally in the housing. As a result, the housing is exposed to the spring forces only after assembly, if it is mechanically strong.

The new construction principle has a number of advantages. On the one hand, with the construction according to the invention, the weight can be significantly reduced with the same heating power, since no metal frame is used, up to about 50 percent. In addition, the heater has no additional measures and no additional weight on exposed metal surfaces. Another advantage is the low height, which is up to 30 percent lower than conventional heaters. As a result, much smaller heaters than conventionally be realized, which nevertheless achieve high efficiency due to the clamping principle used for increasing the electrical and thermal contact. In addition, longer heating elements can be produced, which can be realized with the conventional support frame design only with great effort.

In addition, no conventional position frame is used for spacing and protecting the PTC heating elements, but the PTC heating elements are fixed by pre-positioning on the contact plate via a varnish and separated from each other.

In addition, the production cost compared to conventional heaters is significantly reduced. The manufacture of the heating device according to the invention is much easier, since no special device for overcoming the spring forces of the frame during the manufacturing process is required.

The construction principle requires no special design of the side rails of a holding frame to accommodate the force acting on the longitudinal beams clamping force. The narrow sides the housing according to the invention are therefore adaptable in design to any desired plug geometry surrounding the protruding from the housing connector tongues of the contact sheets.

In addition, the spring is much cheaper to produce in this way. On the one hand, the thickness of the spring can be reduced and thus a material saving can be achieved. On the other hand, the spring element can now be produced for the first time as an endless part and fed from a roll during production. In addition, a single spring element is sufficient.

Claims (35)

1. An electric heating apparatus, particularly as an additional heater for automotive vehicles, comprising a housing (62) which has openings on the elongate housing faces, and a layered structure including at least one PTC heating element (4), a radiator element (5), first and second contact sheets (2, 10) for power supply, the PTC heating element (4) being arranged between the first and second contact sheets (2, 10), and a resilient element (72), wherein the layered structure being kept clamped in the housing (62) by the resilient element (72),
   characterized in that
   the first contact sheet (2) is provided with a lacquer layer (3) at the side facing the PTC heating element (4), and the space between the PTC heating element (4) and the first contact sheet (2) being sealed via lacquer (12) pressed out of said space.
2. The electric heating apparatus according to claim 1, characterized in that the lacquer is an electrically non-conductive silicone lacquer (3).
3. The electric heating apparatus according to claim 1 or 2, characterized in that the lacquer (3) has a viscosity lower than 900 mPa.s, preferably of about 800 mPa.S.
4. The electric heating apparatus according to any one of claims 1 to 3, characterized in that the first contact sheet (2) is made from aluminum.
5. The electric heating apparatus according to any one of claims 1 to 4, characterized in that the second contact sheet (10) is made from brass.
6. The electric heating apparatus according to any one of claims 1 to 5, characterized in that the second contact sheet (10) is tin-plated.
7. The electric heating apparatus according to any one of claims 1 to 5, characterized by an opening (71) provided in the housing (62) for inserting the resilient element (72).
8. The electric heating apparatus according to any one of claims 1 to 7, characterized by a resilient channel formed in the housing (62) for receiving the resilient element (72).
9. The electric heating apparatus according to any one of claims 1 to 8, characterized by positioning means (94) for pre-fixing the elements of the heating apparatus in the housing (62).
10. The electric heating apparatus according to claim 9, characterized in that the positioning means (94) in the housing (62) simultaneously form a groove for guiding the resilient element (72) during insertion.
11. The electric heating apparatus according to any one of claims 1 to 10, characterized in that the elongate faces of the housing are mechanically reinforced by at least one transverse strut (69).
12. The electric heating apparatus according to claim 11, characterized in that the struts (69, 70) in the elongate faces of the housing have the shape of a grid structure.
13. The electric heating apparatus according to claim 11 or 12, characterized in that the grid structure has at least one longitudinal strut (70) in the area of the PTC heating elements (4).
14. The electric heating apparatus according to any one of claims 1 to 13, characterized in that said housing (62) is made from plastics.
15. The electric heating apparatus according to any one of claims 1 to 11, characterized in that the housing (62) comprises two half-shells (62a, 62b).
16. The electric heating apparatus according to claim 15, characterized in that the half-shells (62a, 62b) of the housing (62) can be put together.
17. The electric heating apparatus according to claim 16, characterized by locking pins (78) or locking noses (91) which, when the half-shells (62a, 62b) of the housing (62) are put together, effect a locking of the two half-shells (62a, 62b).
18. The electric heating apparatus according to any one of claims 16 to 17, characterized in that the half-shells (62a, 62b) are configured such that they separate the housing (62) approximately in the middle between the elongate faces of the housing.
19. The electric heating apparatus according to claim 18, characterized by respectively opposite projections (76, 77; 92a, 92b) provided on the separation line of the half-shells (62a, 62b), which will engage each other when the half-shells (62a, 62b) are assembled.
20. The electric heating apparatus according to any one of claims 1 to 19, characterized in that the resilient element (72) is configured such that it transmits the clamping forces essentially onto the reinforced longitudinal sides of the housing.
21. The electric heating apparatus according to any one of claims 1 to 20, characterized in that the resilient element (72) consists of a sheet member (85) with resilient segments (86) projecting therefrom.
22. The electric heating apparatus according to claim 21, characterized in that each of the resilient segments (86) extends into the edge portions of the longitudinal sides of the resilient member (72).
23. The electric heating apparatus according to claim 22, characterized in that the resilient member (72) is made integral with the resilient segments (86).
24. The electric heating apparatus according to any of claims 1 to 23, characterized in that at least one resilient segment (86) for generating clamping forces is provided at each PTC heating element position for a frictional clamping action.
25. The electric heating apparatus according to claim 24, characterized in that at least two resilient segments (86) are provided for each PTC heating element position.
26. A method for producing an electric heating apparatus (20), particularly as an additional heater for automotive vehicles, comprising a housing (62) with openings on the elongate faces of the housing, and a layered structure including at least one PTC heating element (4), a radiator element (5), first and second contact sheets (2, 10) for power supply, and a resilient element (72), the layered structure being kept clamped by the resilient element (72) in the housing (62), with the following mounting steps:

    fastening a PTC heating element (4) to the first contact sheet (2) by means of a lacquer (3),

    inserting the first contact sheet (2) with the PTC heating element (4) fastened thereto and the second contact sheets (2, 10) into a first half-shell (62a) of the housing, and

    attaching the second half-shell (62b) of the housing (62) to the first half-shell (62a).
27. The method according to claim 26, characterized in that the lacquer (3) is an electrically non-conductive silicone lacquer.
28. The method according to claim 26 or 27, characterized in that the lacquer (3) has a viscosity lower than 900 mPa.s, preferably of about 800 mPa.S.
29. The method according to any one of claims 26 to 28, characterized in that the fastening of the PTC heating element (4) via the lacquer (3) only withstands small mechanical loads.
30. The method according to any one of claims 26 to 29, characterized in that the resilient element (72) is inserted through an opening (71) of the assembled housing (62) to effect clamping of the layered structure.
31. The method according to any one of claims 26 to 30, characterized in that along with the insertion of the resilient element (72) the lacquer (3) is pressed out of the area between the PTC heating elements (4) and the contact sheet (2) via the contact pressure generated by the resilient element (72).
32. The method according to any one of claims 26 to 31, characterized in that the lacquer (12) pressed out of the area between the PTC heating element (4) and the contact sheet (2, 10) seals said area against penetrating moisture.
33. The method according to any one of claims 26 to 32, characterized in that the first contact sheet (2) is made from aluminum.
34. The method according to any one of claims 26 to 33, characterized in that the second contact sheet (10) is made from brass.
35. The method according to any one of claims 26 to 34, characterized in that the second contact sheet (10) is tin-plated.

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