Electrical Heating Device and Method of Manufacturing the Same

Abstract

An electrical heating device for a motor vehicle includes an at least partially electrically conductive housing having an end face in which a circumferential groove is provided. A lid, formed from sheet metal, seals the housing. An adhesive is introduced into the groove The lid has a circumferential edge which engages in the groove such that the edge of the lid is immersed circumferentially in the adhesive. The inside dimension of the groove is smaller than the wall thickness of the lid.

Claims

1. An electrical heating device for a motor vehicle, comprising: an at least partially electrically conductive housing having a circumferential groove provided on an end face thereof, a lid which seals the housing, the lid being formed from sheet metal, wherein an adhesive is introduced into the groove, wherein the lid has a circumferential edge which engages in the groove such that the edge of the lid is immersed circumferentially in the adhesive, and wherein an inside dimension of the groove is smaller than a wall thickness of the lid.

2. The electrical heating device according to claim 1, wherein opposing inner surfaces of the groove have projections which are arranged in an offset manner in a longitudinal direction of the groove.

3. The electrical heating device according to claim 1, wherein the housing is a die-cast part, and wherein opposing inner surfaces of the groove have a complementary corrugated course in a top view.

4. A method of manufacturing an electrical heating device for a motor vehicle, comprising: providing an at least partially electrically conductive housing and a lid, the lid being formed from sheet metal with a circumferential edge, a circumferential groove being formed on one end face of the housing, the inside dimension of which is smaller than a wall thickness of the edge; introducing an adhesive into the groove; and introducing the circumferential edge into the groove such that the edge is immersed circumferentially in the adhesive and is deformed between opposing inner surfaces of the groove during introduction into the groove.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further details and advantages of the present invention will be apparent from the following description of an embodiment in conjunction with the drawing. Therein:

[0021] FIG. 1 shows a perspective exploded diagram of an embodiment of an electrical heating device;

[0022] FIG. 2 shows a longitudinal sectional view of a PTC heating assembly of the heating device according to FIG. 1;

[0023] FIG. 3 shows a perspective side view of a schematically shown housing with a lid;

[0024] FIG. 4 shows a longitudinal sectional view through the groove and the edge of the lid for the example according to FIG. 3, and

[0025] FIG. 5 shows a cross-sectional view through the groove and edge of the lid for the example shown in FIG. 3.

DETAILED DESCRIPTION

[0026] FIG. 1 shows an embodiment of an electrical heating device 2 with a multi-part heater housing comprising a housing lower part 4 formed of plastic and a housing upper part 6 integrally formed of metal by means of die casting.

[0027] The housing lower part 4 is trough-shaped and encloses a heating chamber 8 and forms inlet and outlet nozzles 10 which communicate with the heating chamber 8. These inlet and outlet nozzles 10 are integrally formed with the housing lower part 4 by injection molding. A plurality of PTC heating assemblies 12 are shown between the housing upper part 6 and the housing lower part 4.

[0028] As FIG. 2 illustrates, these PTC heating assemblies 12 each have at least one PTC element 14 against which contact elements 16.1; 16.2 abut, forming contact tongues 18 which protrude beyond a metal housing 20. The PTC element 14 is accommodated in a frame 22 and between the contact elements 16.1; 16.2. Insulating layers 26 are provided between the metallic housing 20 and a heating cell 24 formed by the two contact elements 16.1; 16.2 and the PTC element 14.

[0029] The PTC heating assemblies 12 are held in plug-in contact in an accommodation 28 provided for this purpose in a partition wall 30 of the housing upper part 6 and are electrically connected and controlled in a connection chamber 29 of a control system 32. Details of this configuration are described in EP 3 334 242 A1, which originates from the applicant.

[0030] In FIGS. 1 and 3, reference sign 34 characterizes a lid which is connected to the housing upper part 6 in a sealing and electrically conductive manner. This component, also referred to as housing 20 in the following, is shown in a perspective side view in FIG. 3. It is evident that the housing 6 has a circumferential groove 36, the course of which corresponds to the geometry of an edge 38 of the lid 34. The configuration of the groove 36 can be seen in particular in FIGS. 4 and 5. As FIG. 4 illustrates, opposing inner surfaces 42, 46 of the groove 36 have a corrugated course in the top view of the groove 36. The corrugated course is complementary. Depths 40 on a first inner surface 42 are opposite to pitches 44 of the other, second inner surface 46 of the groove 36. This results in a channel characterized by reference sign 48, which has an identical width over its entire course.

[0031] FIG. 5 illustrates the arrangement of the edge 38 within the groove 36. Reference sign 50 characterizes an adhesive within the groove 36. After the edge 38 is inserted into the groove 36, the adhesive 50 is partially displaced within the groove 36. It rises within the groove 36. The adhesive 50 is dimensioned such that after the insertion of the edge 38 into the groove 36 is complete, the adhesive 50 is not displaced beyond the groove 36. The installation position of the edge 38 is reached when the front free end of the edge 38 abuts the bottom of the groove 36. As FIG. 5 illustrates, the edge of the lid 38 is in good electrical contact with the right-hand pitch 44, whereas adhesive 50 is provided on the opposite side and in the remainder of the depth 40. All spaces within the groove 36 are filled by the adhesive 50. The adhesive 50 is absent only where the edge 38 is in direct contact with the inner surfaces 42, 46 of the groove 36.