Electric Heating Device

Abstract

An electric heating device comprises a housing with a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one heating rib protrudes in the direction toward the heating chamber and forms a receiving pocket. A PTC heating device is received in the receiving pocket and includes at least one PTC element and conductor tracks which are electrically connected in the connection chamber for energizing the PTC element with different polarities and which are connected to PTC element r in an electrically conductive manner. A profile member is provided between the PTC heating device and an inner side of the receiving pocket and is connected to the receiving pocket by way of a tongue and groove connection which extends in the direction of insertion of the receiving pocket.

Claims

1. An electric heating device comprising: a housing with a partition wall which separates a connection chamber from a heating chamber for dissipating heat and from which at least one heating rib protrudes in the direction toward the heating chamber and forms a receiving pocket; a PTC heating device received in the receiving pocket, the PTC heating device including at least one PTC element and conductor tracks that are electrically connected in the connection chamber for energizing the PTC element with different polarities, the conductor tracks being connected to the PTC element in an electrically conductive manner, wherein a profile member is provided between the PTC heating device and an inner side of the receiving pocket and is connected to the receiving pocket by way of a tongue and groove connection which extends in a direction of insertion of the receiving pocket.

2. The electric heating device according to claim 1, wherein the profile member forms a U-shaped receptacle that opens towards the connection chamber for the PTC heating device.

3. The electric heating device according to claim 1, wherein the PTC element has main side surfaces, and wherein tongue and groove connections are provided between each main side surface of the PTC element and the oppositely disposed inner side of the receiving pocket.

4. The electric heating device according to claim 1, wherein the PTC element has main side surfaces, and wherein a plurality of tongue and groove connections is provided between one of the main side surfaces of the PTC element and the oppositely disposed inner surface of the receiving pocket.

5. The electric heating device according to claim 1, wherein at least one groove defining projection that defines the groove is pivotable about an axis extending in the direction of insertion.

6. The electric heating device according to claim 1, wherein at least one tongue projection that at least in part forms the tongue is pivotable about an axis extending in the direction of insertion.

7. The electric heating device according to claim 5, wherein at least one tongue projection that at least in part forms the tongue is pivotable about an axis extending in the direction of insertion.

8. The electric heating device according to claim 1, wherein at least one groove defining projection that defines the groove is tapered towards a free end thereof and is in a wedge shape.

9. The electric heating device according to claim 1, wherein at least one tongue projection that at least in part forms the tongue is tapered towards a free end thereof and is in a wedge shape.

10. The electric heating device according to claim 8, wherein at least one tongue projection that at least in part forms the tongue is tapered towards a free end thereof and is in a wedge shape.

11. The electric heating device according to claim 1, wherein at least one groove defining projection that defines the groove is formed integrally on the receiving pocket.

12. The electric heating device according to claim 1, wherein at least one tongue projection that at least in part forms the tongue is formed integrally on the receiving pocket.

13. The electric heating device according to claim 11, wherein at least one tongue projection that at least in part forms the tongue is formed integrally on the receiving pocket.

14. The electric heating device according to claim 1, wherein at least one compression element is provided between the profile member and a main side surface of the PTC element.

15. The electric heating device according to claim 1, wherein curing adhesive is introduced into the receiving pocket and is at least in part received in the one tongue and groove connection.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further details of the present invention shall arise from the following description of an embodiment in combination with the drawing, in which:

[0029] FIG. 1 shows a cross-sectional view of part of an electric heating device;

[0030] FIG. 2 shows a perspective side view of a profile member of the electric heating device according to FIG. 1;

[0031] FIG. 3 shows a sectional view taken along line III-III according to the illustration in FIG. 1; and

[0032] FIG. 4 shows a sectional view taken along line III-III according to the illustration in FIG. 1 for a variant of the profile member.

DETAILED DESCRIPTION

[0033] FIG. 1 shows the essential components of an electric heating device 100 with a housing 102 made of a material with good thermal conductivity, presently die-cast aluminum. The housing 100 forms a wall 104 circumferentially surrounding a heating chamber 102. In FIG. 1, the heating chamber 102 is still open on the underside since a base which closes the housing 100 on the underside is not illustrated in FIG. 1. The same applies to a control housing cover which is connected to the housing 100 on the oppositely disposed side for covering and surrounding a connection chamber identified with reference numeral 106. The housing 100 forms a partition wall 108 integrally between the heating chamber 102 and the connection chamber 106. Heating ribs 110 protrude from this partition wall 108 into the heating chamber 102. The heating ribs 110 are closed at their lower end that protrude into the heating chamber 102. As elucidated in FIG. 1, the heating ribs 110 are formed together with the partition wall 100 and the wall 104 from an integrally die-cast aluminum housing 100.

[0034] The heating ribs 110 form a receiving pocket 112 which tapers downwardly in a wedge shape. The PTC heating device identified with reference numeral 114 is received in this receiving pocket 112. As illustrated in the sectional view according to FIG. 1, the PTC heating device 114 comprises a PTC element 116, on the main side surfaces of which there are conductor tracks 118 which in the present case comprise a wire mesh made of electrically conductive material. An insulating layer 120 is present on the side of the conductor element 118 disposed opposite the PTC element 116 and can be formed by a ceramic layer and/or an insulating plastic film The gap between the insulating layer 120 and the PTC element 116 is overall filled by the conductor track 118. For this purpose, the free spaces between the wire mesh are filled with highly thermally conductive adhesive, which is part of the conductor track 118. The wire mesh projects beyond the PTC element to form contact strips 122 which are shown in FIG. 1. These contact strips 122 are exposed in the connection chamber 106. The PTC element 116 and the insulating layer 120 are joined to form a unit by the adhesion bonding of the conductor track 120. Compression elements 124 in the form of corrugated spring steel sheets that can be seen in FIG. 3 are disposed on the outer side of this PTC heating device 114.

[0035] FIGS. 2 and 3 clearly show a profile member 126 which forms a U-shaped receptacle and comprises two side faces 130 connected by way of an integral hinge 128. The compression elements 124 abut against the inner side of this profile member 126 (cf. FIG. 3).

[0036] Respective groove defining projections 132, which in pairs each enclose a groove 134 between them, project from the oppositely disposed outer side of the side faces 130. As is illustrated in particular in FIG. 3, a plurality of identically configured grooves 134 are recessed in this form on the outer side of the side faces 130. The grooves 134 extend in the direction of insertion of the receiving pocket 112, which is identified as E in FIG. 1.

[0037] Tongue projections 136 again protrude from the inner side of the receiving pocket 112. These tongue projections 136 are integrally formed onto the die-cast housing 100. As is conveyed by the cross-sectional view according to FIG. 3, the tongue projections 136 taper towards their free end in a wedge shape. In a corresponding manner, the groove defining projections 132 are also configured to taper in a wedge shape towards their free front end. It goes without saying that only the surfaces of the groove defining projections 132 that respectively define the groove 134 have such a configuration. To elucidate this situation, the tongue projections 136 are omitted in FIG. 3 on the right-hand side.

[0038] In the embodiment shown in FIG. 3, the profile member 126 is first equipped with the PTC heating device 114 and the compression elements 126 during assembly. The assembly pre-assembled in this manner is thereafter inserted into the receiving pocket 112. The tongue projections 136 there engage in the grooves 134 associated with them. A deformation in the region of the groove defining projections 132 is evident from the comparison of the right-hand side to the left-hand side according to FIG. 3. It causes a certain tolerance compensation. The compression element 124 is additionally deformed for tolerance compensation. After successful assembly, the compression element 124 ideally abuts substantially over its entire surface, firstly, against the inner surface of the profile member 126 and, secondly, against the outer side of the insulating layer 120.

[0039] The compression element 124 can be made of aluminum, copper, copper beryllium, or some other material with good thermal conductivity that applies permanent resilient preload forces.

[0040] Remaining cavities in the receiving pocket 112 can be filled with a highly thermally conductive mass, for example, a curing plastic mass filled with thermally conductive particles.

[0041] In the variant shown in FIG. 4, the groove defining projections 132 are connected to the remainder of the profile member 126 by way of a relatively thin web 140. This web 140 creates a pivot axis which extends substantially in the direction of insertion E. In this embodiment, compression elements can be dispensed with. Adjacent groove defining projections 132 for different grooves 134 are spaced sufficiently far from one another so that they can each pivot about their pivot axis without striking against one another when the wedge-shaped tongue projections 136 are introduced. This enables considerable tolerance compensation. The layers of the PTC heating device 114 within the profile member 126 are there applied with good resilient tension against the inner surface of the profile member 126, thereby improving heat extraction.

[0042] FIG. 4 also illustrates the bulging of the inner surface of the profile member 126 in such a way that, in a cross-sectional view, it abuts against the insulating layer 120 each substantially in a punctiform manner in the longitudinal linear direction. This deformation of the profile member 126 causes additional resilient tensioning of the PTC element 116 in the receiving pocket 112 as well.