Electrically heatable heating disk

Abstract

An electrically heatable heating disk for use within a device for the aftertreatment of exhaust gas, wherein the heating disk is formed by a layer stack formed from a multiplicity of metal foils which are stacked one on top of the other, the layer stack being wound to form a honeycomb body, wherein the layer stack has alternately arranged, coarsely structured metal foils and finely structured or smooth metal foils, and wherein the honeycomb body has at least one electrical contact at a radial edge region, wherein first metal foils terminate with an offset with respect to one another as a result of the winding in the circumferential direction of the heating disk, wherein finely structured or smooth second metal foils which extend in the circumferential direction extend beyond the respective ends of the terminating first metal foils in the circumferential direction.

Claims

1. An electrically heatable heating disk for use within a device for the aftertreatment of exhaust gas, the heating disk comprising: a layer stack formed from a plurality of coarsely structured metal foils and a plurality of finely structured or smooth metal foils, which are alternately arranged, and are stacked one on top of the other, and the layer stack being wound to form a honeycomb body; and at least one electrical contact arranged at a radial end region of the honeycomb body; wherein the plurality of coarsely structured metal foils terminate with an offset with respect to one another as a result of the winding in the circumferential direction of the heating disk, and the plurality of finely structured or smooth second metal foils extend in the circumferential direction beyond the respective ends of the plurality of coarsely structured metal foils; wherein a portion of each of the plurality of finely structured or smooth metal foils, which protrudes in the circumferential direction beyond the respectively directly adjacent plurality of coarsely structured metal foils, include a material thickness which is increased in comparison with the rest of the extent of the respective finely structured or smooth metal foil, and wherein the portion of each of the plurality of finely structured or smooth metal foils which includes the material thickness which is increased begins directly before the termination of the respective directly adjacent plurality of coarsely structured metal foils.

2. The electrically heatable heating disk of claim 1, wherein the thickness of the portion of each of the plurality of finely structured or smooth metal foils, which protrudes in the circumferential direction beyond the respectively directly adjacent plurality of coarsely structured metal foils, is higher by a factor of 1.5 to four in comparison with the rest of the extent of the respective finely structured or smooth metal foils.

3. The electrically heatable heating disk of claim 1, wherein the plurality of finely structured or smooth metal foils extend in the circumferential direction as far as an end region.

4. The electrically heatable heating disk of claim 1, wherein the electrical contact is arranged at the part of each of the plurality of finely structured or smooth metal foils which protrude in the circumferential direction beyond the plurality of coarsely structured metal foils.

5. The electrically heatable heating disk of claim 1, wherein the plurality of finely structured or smooth metal foils which extend over the terminating plurality of coarsely structured metal foils, are arranged in a radial edge region of the honeycomb body.

6. The electrically heatable heating disk of claim 1, the honeycomb body further comprising two electrical contacts, wherein at least one of the two electrical contact between a power supply or a power discharge and the layer stack occurs in each case in a region which is formed from plurality of finely structured or smooth metal foils which protrude in the circumferential direction beyond the plurality of coarsely structured metal foils.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in detail below on the basis of an exemplary embodiment and with reference to the drawing. In the drawing:

(2) FIG. 1 shows a sectional view through an inventive honeycomb body of an electrically heatable heating disk.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

(4) FIG. 1 shows a sectional view through part of a heating disk 1 which is produced from a wound-on layer stack. The heating disk 1 is formed from a layer stack which is composed of a multiplicity of wound-on metal foils 2, 3. In the exemplary embodiment shown, first metal foils 2 with a coarse structure or coarse corrugations are shown, and second metal foils 3 with a fine structure or micro-corrugations are shown.

(5) The first and second metal foils 2, 3 are stacked alternately one on top of the other and therefore form the layer stack. The heating disk 1 is generated by the winding on of the layer stack.

(6) FIG. 1 shows the radially outer end region of the layer stack which is wound on to form the heating disk 1. The first metal foils 2 are all of the same length. As a result of the winding on, the first metal foils 2 move relative to one another in the circumferential direction and as a result of the different radii which the first metal foils 2 assume in the wound-on state, a sickle-like shape is produced for the first metal foils 2 which terminate with an offset with respect to one another in the circumferential direction 4.

(7) The second metal foils 3 are made longer than the first metal foils 2 and therefore extend further in the circumferential direction 4 than the terminating first metal foils 2. The successive termination of the first metal foils 2 increasingly reduces the thickness of the layer stack in the circumferential direction 4. After the termination of the last first metal foil 2, the layer stack is finally formed just from the relatively long second metal foils 3. In this region which is only then formed from the second metal foils 3, the layer stack has a significantly smaller thickness, since the first metal foils 2 no longer project into this region. This is seen clearly since the cells formed by the coarse structure of the first metal foils 2 are no longer present in this region.

(8) The second metal foils 3 are embodied in such a way that they have a thickening directly before the termination of the respectively directly adjacent first metal foil 2, wherein the second metal foils 3 have this increased thickness of material up to their own end region. In addition, the top metal foil and the bottom metal foil of the layer stack, which are both formed by finely structured second metal foils 3, also each have an increased thickness of material. The thickening of these two metal foils 5 already takes place before the first termination of the first metal foil 2, when viewed in the circumferential direction 4. This thickening also serves, inter alia, to increase the stability of the heating disk 1.

(9) The reference number 6 indicates an electrical contact which serves to introduce the current or to discharge the current into the layer stack or discharge it therefrom. The electrical contact 6 is arranged in a region which is formed completely from second metal foils 3.

(10) FIG. 1 does not have a limiting character and serves to clarify the inventive concept.

(11) The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.