HEATING DEVICE FOR HEATING AN AIR FLOW IN A MOTOR VEHICLE

Abstract

A heating device for heating an airflow in a motor vehicle is described, with a plurality of heating rods, which have connection plates made of aluminium, or an aluminium-based alloy, and a circuit board, which carries a control circuit, to which the heating rods are connected by way of busbars. In accordance with this disclosure, provision is made for the busbars to have a body made of aluminium, or an aluminium-based alloy, which establishes contact with the heating rods by means of a welded connection, and an end piece made of copper, or a copper-based alloy, which establishes contact with the circuit board by means of a plug-in connector.

Claims

1. A heating device for heating an air flow in a motor vehicle, the heating device comprising: a plurality of heating rods that have connection plates made of aluminium or an aluminium-based alloy; and a circuit board carrying a control circuit to which the heating rods are connected by busbars, wherein the busbars have a body made of aluminium or an aluminium-based alloy that establishes contact with the heating rods by a welded joint, and the busbars have an end piece made of copper or a copper-based alloy that establishes contact with the circuit board by a plug-in connector.

2. The heating device according to claim 1, wherein the end piece forms a contact pin.

3. The heating device according to claim 2, wherein the contact pin is a press-in contact, which is pressed into a corresponding opening in the circuit board.

4. The heating device according to claim 3, wherein the contact pin has a bulging center section, which presses against the wall of the opening.

5. The heating device according to claim 1, wherein the end piece is provided with a metallic coating.

6. The heating device according to claim 5, wherein the metallic coating is tin, or a tin-based alloy.

7. The heating device according to claim 1, wherein the end piece is positively attached in a form fit to the body.

8. The heating device according to claim 1, wherein the end piece is attached to the body by a shaping joining process, preferably by a press joining process.

9. The heating device according to claim 1, wherein the end piece is attached to the body by toxing or clinching.

10. The heating device according to claim 1, wherein the heating rods in each case have a potential connection connected to one of the busbars and an earth connection connected to another of the busbars.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0015] FIG. 1 shows a schematic illustration of a heating device for heating an air flow in a motor vehicle;

[0016] FIG. 2 shows a sectional view of a detail of the heating device, which illustrates the electrical connection between one of the heating rods and a circuit board;

[0017] FIG. 3 shows the heating device with the housing open, and the circuit board raised; and

[0018] FIG. 4 shows a detail view of a further example of embodiment of a heating device for heating an airflow in a motor vehicle.

DESCRIPTION

[0019] The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

[0020] The heating device shown in FIG. 1 serves to heat an air flow in a motor vehicle, and can be used, for example, as part of an air conditioning system to heat the passenger compartment. The heating device comprises a plurality of heating rods 1, for example three to eight heating rods, which in each case are connected to heat dissipation elements 2, for example to sheet metal fins pushed onto the heating rods. However, the heat dissipation elements 2 can also be formed integrally with the heating rods 1, as is known in the art, for example, from DE 10 2006 018 784 B4.

[0021] The heating rods 1 project with their connection-side ends into a housing 3, in which they are connected to a control circuit for purposes of controlling the heating function. FIG. 2 shows schematically in a sectional view a detail of the heating device, in which is illustrated the connection of a heating rod 1 to a circuit board 4, which carries the control circuit.

[0022] The heating rod 1 has heating resistors (not shown) made of a PTC ceramic, with which contact plates 5 establish electrical contact. Only one of these contact plates 5 is illustrated in FIG. 2. The contact plates 5 are connected to the circuit board 4 by busbars. Only one of these busbars is illustrated in FIG. 2. The busbar has a body 6a of an aluminium-based alloy, which is welded at a contact point 7 to the contact plate 5 of an aluminium-based alloy, and an end piece 6b of copper, or a copper-based alloy, which is inserted into an opening of the circuit board 4 and establishes electrical contact with the control circuit on the circuit board.

[0023] The body 6a and the end piece 6b of the busbar are positively connected in a form fit to each other at the point 8, for example by toxing, clinching or another shaping joining process.

[0024] In the example shown, the end piece 6b of the busbar protrudes through the circuit board 4, and is inserted into a female plug-in connector 9. The end piece 6b thus forms a contact pin, which in this example is designed as a contact tongue.

[0025] The end piece 6b is provided with a metallic coating, for example, it is tin-plated. In this way, corrosion of the end piece can be prevented, and an advantageously low contact resistance onto the circuit board 4 can be permanently achieved.

[0026] FIG. 3 shows the heating device with the housing removed, and the circuit board 4 raised, so that the contact plates 5 of the individual heating rods and the busbars 6 can be seen. As can be seen, each heating rod has two contact plates 5, in each case welded to the body 6a of a different busbar 6. The contact plate for earth is welded to the body of a busbar for earth, and the contact plate for potential is welded to the body of a busbar for potential.

[0027] FIG. 4 shows a detail view of a further example of embodiment of a heating device for heating an air flow in a motor vehicle, with the housing and circuit board removed. The contact plates 5 of a plurality of heating rods, and the busbars 6 that establish contact with them, can be seen in FIG. 4. The difference from the example of embodiment explained above is limited to the configuration of the end pieces 6b of the busbars 6.

[0028] In the example of embodiment in FIG. 4, the end pieces 6b form a contact pin in the form of a press-in contact. The press-in contact forms an electrical contact with metalized walls of a corresponding opening of the circuit board. The press-in contact has a bulging center section, with which contact is established with the metalized walls of an opening of the circuit board. The press-in contact can be of solid design, or can have an opening that is enclosed by spring clips.

[0029] The end piece 6b is also positively connected in a form fit to the body 6a of the busbar 6 in the example of embodiment of FIG. 4. Here the body 6a of the busbar 6 forms two arms, which grip the end piece 6a on its narrow sides, and engage with a lateral recess of the end piece 6a.

[0030] While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

LIST OF REFERENCE SYMBOLS

[0031] 1 Heating rod [0032] 2 Heat dissipation element [0033] 3 Housing [0034] 4 Circuit board [0035] 5 Contact plate [0036] 6 Busbar [0037] 6a Body [0038] 6b End piece [0039] 7 Contact point [0040] 8 Contact point [0041] 9 Plug-in connector