Connecting thermally-sprayed layer structures of heating devices

Abstract

A heating device for a domestic appliance includes a planar carrier having a carrier surface. Thermally sprayed onto the carrier surface is a layer structure, and a first solder volume is applied to the layer structure. The solder volume is an ultrasonically soldered-on solder volume. The layer structure can hereby be a heating conductor layer.

Claims

1. A heating device for a domestic appliance, comprising: a planar carrier having an insulating carrier surface, a first metallic layer structure thermally sprayed directly onto the insulating carrier surface, a second metallic layer structure thermally sprayed directly onto the insulating carrier surface, and a first volume of solder ultrasonically melted onto the first metallic layer structure, the second metallic layer structure, and the insulating carrier surface.

2. The heating device of claim 1, wherein the first layer structure is a heating conductor layer.

3. The heating device of claim 1, wherein the first volume of solder electrically connects the first layer structure to another component of the heating device.

4. The heating device of claim 1, further comprising a second volume of solder which is not applied by ultrasound and electrically connects the first volume of solder to another component of the heating device.

5. The heating device of claim 3, wherein the other component is a metallic contact.

6. The heating device of claim 5, wherein the metallic contact is a contact of an electrical or electronic component.

7. The heating device of claim 1, wherein a second volume of solder covers at least a portion of the first layer structure without connecting the first layer structure electrically to another electrically conductive component of the heating device.

8. A domestic appliance, comprising: a heating device, said heating device comprising a planar carrier having an insulating carrier surface, a first metallic layer structure thermally sprayed directly onto the insulating carrier surface, and a first volume of solder ultrasonically melted onto both the metallic layer structure and the insulating carrier surface, wherein the first volume of solder electrically connects the first layer structure to another component of the heating device, the other component is a second metallic layer structure thermally sprayed onto the carrier surface; and the first volume of solder is applied to the second metallic layer structure.

9. The domestic appliance of claim 8, wherein the first layer structure is a heating conductor layer.

10. The domestic appliance of claim 8, further comprising a second volume of solder which is not applied by ultrasound and electrically connects the first volume of solder to another component of the heating device.

11. The domestic appliance of claim 8, wherein the other component is a metallic contact.

12. The domestic appliance of claim 11, wherein the metallic contact is a contact of an electrical or electronic component.

13. The domestic appliance of claim 8, wherein the first volume of solder covers at least a portion of the layer structure without connecting the layer structure electrically to another electrically conductive component of the heating device.

14. A method for producing a heating device for a domestic appliance, said method comprising: thermally spraying a first metallic layer structure directly onto a planar carrier having an insulating carrier surface, ultrasonically soldering a first volume of solder onto both the metallic layer structure and the insulating carrier surface, wherein ultrasonically soldering includes melting the volume of solder, and ultrasonically soldering the first layer structure in two stages to another component of the heating device, with a first one of the two stages representing the ultrasonic soldering of the first volume of solder onto the layer structure, and with a second one of the two stages including soldering the first volume of solder to the other component of the heating device, wherein the other component of the heating device is a second layer structure that is thermally sprayed onto the planar carrier; and wherein in the second of the two stages the first volume of solder is soldered to a second ultrasonically applied volume of solder of the heating device.

15. The method of claim 14, further comprising ultrasonically soldering the layer structure in one stage to another component of the heating device.

16. The method of claim 14, wherein the ultrasonic soldering is carried out by using an ultrasonic soldering iron.

17. The method of claim 14, wherein the ultrasonic soldering is carried out by using an ultrasonic solder bath.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-described properties, features and advantages of this invention and the manner in which this is achieved will now be described more clearly and intelligibly with an exemplary embodiment, illustrated in the following schematic description of an exemplary embodiment, which will be described in detail making reference to the drawings.

(2) FIG. 1 is a plan view sketch of a heating device of a domestic appliance;

(3) FIG. 2 is a sectional representation in side view of a first portion of the heating device of FIG. 1;

(4) FIG. 3 is a sectional representation in side view of a second portion of the heating device of FIG. 1;

(5) FIG. 4 is a sectional representation in side view of a third portion of the heating device of FIG. 1; and

(6) FIG. 5 is a sectional representation in side view of a fourth portion of the heating device of FIG. 1.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE PRESENT INVENTION

(7) FIG. 1 shows a plan view of a heating device 1 of a domestic appliance H. The heating device 1 can be used, for example, for heating water situated in a water tank of a steam generator. The domestic appliance H can, however, also be an oven with a steam cooking capability, a dedicated steam cooker, an electrically heatable cooking chamber partition, a laundry care appliance, a dishwasher, a small domestic appliance, etc.

(8) The heating device 1 has a planar carrier 2 (e.g. made of a metal sheet) with an electrically insulating carrier surface 3 (e.g. made of a light porous, for example thermally sprayed-on, ceramic layer). A plurality of metallic layer structures 4 to 8 are thermally sprayed onto the carrier surface 3. The thermally sprayed-on layer structures 4 to 8 are electrically insulated from one another by the carrier surface 3 and comprise: a first (long) meandering heating conductor line 4, a second (short) meandering heating conductor line 5 and three short straight conductor lines 6 to 8.

(9) The two heating conductor lines 4 and 5 are electrically connected to one another by two tracks 9 made of a first solder or solder material 10. By this means, the two heating conductor lines 4 and 5 are electrically connected in series. If the second heating conductor line 5 is not to be used, in place of the two tracks 9, the two corresponding ends of the first heating conductor line 4 could be directly connected to one another by means of a track made of the first solder material 10 (not shown). The electrical resistance can also be exactly trimmed in that a position of the lower track 9 here between the heating conductor lines 4 and 5 can be varied, as indicated by the double arrow. By means of a suitable placement of the tracks 9, the common heating conductor line 4, 5 can consequently be trimmed.

(10) As shown in FIG. 2 in section A-A, for this purpose, the track 9 of the first solder material 10 has been ultrasonically soldered on in one stage from the surface of the first heating conductor line 4 across the carrier surface 3 to the surface of the second heating conductor line 5. Herein, due to the ultrasonic energy introduced, the first solder material 10 holds both on the heating conductor lines 4 and 5 as well as on the carrier surface 3 without flux being needed for this. The track 9 can be applied, for example, by means of a soldering with an ultrasonic soldering iron.

(11) Referring again to FIG. 1, the three straight thermally sprayed-on conductor lines 6 to 8 are connected to a connector plug 11 of the heating device 1, in particular to respective electrical contacts 11a of the connector plug 11. Adjacent conductor lines 6 and 7 or 7 and 8 are connected via respective SMD components 12. The SMD components 12 are herein, by way of example, NTC resistors which have electrical contacts or contact fields 14 at their end regions in the form of solder terminals. Thus, via the plug frame 11, measurement values (e.g. electrical resistance values, voltage values or current values) associated with a respective temperature can be read off.

(12) The SMD components 12 are fastened via soldering points 13 from the first solder material 10 and a second solder material 15 to the conductor lines 6 and 7 or 7 and 8, as shown in FIG. 3 as a section B-B of the heating device 1. Herein, the conductor lines 6 and 7 or 7 and 8 have been ultrasonically soldered with a solder volume of the first soldier material 10. Consequently, the SMD components 12 have been placed with their contact fields 14 on respective solder volumes of the solder material 10. Then, the solder volumes of the solder material 10 have been soldered to the associated contact fields 14 by means of a non-ultrasonic soldering method (e.g. a laser soldering, reflow soldering, hand soldering, etc.) using the second solder material 15. The first solder material 10 and the second solder material 15 can be the same or different.

(13) Consequently, the two conductor lines 7 and 8 are electrically connected to one another by means of the SMD component 12 via the soldering points 13, which have (partial) solder volumes 13a and 13b of the first solder material 10 and/or the second solder material 15.

(14) Similarly, for example, the electrical contacts 11a (e.g. contact posts or contact pins) of the connector plug 11 are mounted on the conductor lines 6 to 8, wherein they can have been dipped in a solder bath (not shown) before the mounting of the connector plug 11. The solder bath can function with or without an ultrasonic input. The solder material introduced in the solder bath can be, for example, one of the solder materials 10 or 15.

(15) Referring again to FIG. 1, in addition, two metallic contact areas 16 are applied to the carrier surface, by means of which the combined heating conductor line 4 and 5 can be electrically connected at the end, for example, to a voltage supply. In this regard, FIG. 4 shows a sectional representation in a side view of a section C-C of the heating device 1.

(16) In this regard, similarly to FIG. 3, a solder volume (solder point) 17 of the first solder material 10 has been ultrasonically soldered onto the thermally sprayed-on heating conductor line 4, and then a track 18 of the second solder material 15 has been drawn with another soldering method (not involving ultrasound) from the solder volume 17 to the metallic contact area 16, or vice versa.

(17) Similarly, the two thermally-sprayed heating conductor lines 4 and 5 could also each be provided with ultrasonically soldered-on solder volumes 17 of the first solder material 10, which are connected to one another via a track 18 of the second solder material 15.

(18) Referring once more to FIG. 1, at a bend in the heating conductor line 4, a conducting layer 19 has also been ultrasonically soldered only onto the heating conductor line 4 and, if appropriate, the carrier surface 3, in order to reduce a current density there and so to prevent a formation of “hot spots”, as shown in the section D-D in FIG. 5.

(19) Naturally, the present invention is not restricted to the exemplary embodiment disclosed.

(20) In general, “a”, “an”, etc. can be understood as singular or plural, in particular in the sense of “at least one” or “one or more”, etc., provided this is not explicitly excluded, e.g. by the expression “exactly one”, etc.

(21) A numerical value can also include the given value as a typical tolerance range, provided this is not explicitly excluded.