EP1337129B1 - Electrical heating element for heating seats and steering-wheels - Google Patents

Abstract

Electrical heating element for heating units of seats and steering wheels, comprises conductor(s) having core-coated wire(s) that serves as heat conductor(s) (1), contact conductor (3) or lead of temperature probe. The core of the wire comprises copper or copper alloy, and the core comprises steel or vice versa. Independent claims are also included for: (a) a seat heating unit or steering wheel, and a seat which both contain heating element(s); and (b) a seat containing at least one heating element.

Description

The invention relates to a heating element for a seat.

For heating seats, especially in passenger cars, mainly tin-plated or silver-plated copper conductors are used. In spite of this coating, depending on the environmental conditions, these heating conductors exhibit corrosion phenomena which are induced by moisture and the influence of salts. Due to these corrosion phenomena, heat conductor-damaging cross-sectional reductions occur, resulting in local overheating and, finally, breakage of the heat conductor, resulting in a shortened life of the heat conductor. Furthermore, the coating with silver or tin or other metals so far increase the friction of the individual filaments of the heat conductor that the heating conductor bend due to its increased stiffness and thus can be severely damaged. Another disadvantage of a metallic coating of the individual Heizleiterfilamente is the very different redox potential of the coating metals over the actual wire material. In the event that the coating is not free of pores and defects are present, sets under the influence of an electrolyte formed from water and salt corrosion and thus the dissolution of the less noble metal, which in turn represents a damage of the heating element. Finally, the mechanical requirements in seats on such ladder are very high, which are not solved satisfactorily in many cases.

In DE 38 32 342 C1 For example, a cladding wire having a sheath of platinum enveloping a core of an alloy of 1 to 5% by weight of tungsten, balance palladium, is disclosed. This jacket wire is preferably used as a lead wire for resistance thermometer with a measuring resistor made of platinum.

DE 31 25 980 A1 discloses a wire-shaped semi-finished product for an electrical conductor wire having a certain maximum diameter, which consists essentially of platinum at least in the region of its free surface, wherein the surface is covered with a gold layer, wherein the core of the conductor wire may consist of nickel.

The disadvantage here is, inter alia, the use of difficult to process materials and their high price.

Thus, there is the problem of providing an electrical heating element which avoids these disadvantages, in particular that withstands the high mechanical stresses of an electric seat heating in a seat, especially in a motor vehicle seat and at the same time excellent electrical conductivity, coupled with a low corrosion susceptibility has at relatively low production costs.

This problem is solved by an arrangement according to claim 1 and a seat according to claim 12.

The electric heating element according to the invention comprises at least one stranded wire with at least one core-sheath wire, wherein the sheath of a steel and the core of copper or a copper alloy or the sheath of copper or a copper alloy and the core consists of a steel, wherein is advantageous if the steel is a carbon steel, as has proven in practice.

In the context of the invention, a strand consists of at least one strand of strand, which in turn consists of at least one wire, but advantageously at least two wires.

Due to the special choice of materials and the specific mechanical structure of the wire has the above-mentioned necessary properties in particular extent. The strand can be used as a heating conductor and / or as a contact conductor (for contacting the heating conductors, in particular in knitted fabrics, see: DE 41 36 425 and DE 100 14 819 ) and / or as a supply of temperature sensors (sensors, such as PCT and NTC elements) act. In particular, in the embodiment as a heat conductor, contact conductor and supply line, a special inexpensive and secure embodiment is provided.

The following embodiments have proven to be advantageous in practice.

The copper alloy contains copper and nickel and / or the steel is a stainless steel according to DIN 4401. Surprisingly, this type of steel has been found to have a particularly long service life of many thousands of hours.
The copper alloy consists of 90-10% copper by weight and 10-90% nickel by weight.
Core and shell have cross-sectional areas in the ratio 1: 3 to 3: 1.
Core and shell have at least approximately equal cross-sectional areas.
The wire diameter is 0.01 - 0.5 mm.
In order to provide a high corrosion protection against external influences, the wire has an external electrical insulation.
This is advantageously made of PTFE (polytetrafluoroethylene), FEP (copolymers of tetrafluoromethylene and hexafluoropropylene), MFA (perfluoroalkoxy polymer) or polyurethane varnish.
The strand contains at least one left and at least one right-handed strand strand in order to minimize the tendency to torsion and to be able to lay the strand according to the requirements without axial Aufwikkeln can.
This is especially true for multiple strand strands, if the number of left and right-rotating strand strands is the same.
The strands used according to the invention usually have 1 strand strand to about 100 strand strands, wherein the strand strands usually have 1 wire to about 100 wires.
The strand is fastened in and / or to a carrier material, in particular to a foam body and / or a knitted fabric, in particular by partial or short weft (in terms of textile effect). At this point, it should be mentioned that the over- and suturability of the stranded wire (in terms of textile effect) turned out to be excellent.

The advantages listed above also apply analogously to a heating element containing a heating element, a seat, in particular a motor vehicle seat, and a corresponding steering wheel.

Another essential aspect of the invention is the use of a stranded wire for the electrical connection of divided by a Abspanngraben a seat electrical heating elements of seat parts. At least one such strand acts in this case as a bridge strand (ie a highly flexible strand between the two seat parts, which acts as a kind of "bridge"), which are usually soldered to the individual heating elements of the seat parts in an electrically connecting manner.

Finally, the use of the above strand as a heat conductor and / or contact conductor and / or supply of a temperature sensor in heating elements and for heating a steering wheel and / or seat is proposed as the case here placed on strands high demands on the mechanical and electrical quality also be met.

Finally, attention should be drawn to the very advantageous use of the indicated stranded wire and the heating element for the 42-volt on-board network technology, since this surprisingly results in a particularly long life beyond the actually expected.

Although there have been serious problems with mechanical stability in this field for decades, only with the present invention has it been possible to obtain satisfactory results. Surprisingly, it is the combination of the materials and the relative arrangement of each other as a core-shell material.

The term "trench" is to be understood as the area of a padded seat on which an outer seat cover is pulled "inwards" and fastened with an inner support frame. The result is a kind of "digging", which in turn is surrounded by two adjacent padding beads. The unclamping of the seat cover is used primarily to avoid any occurring distortions of the seat cover for non-profiled seat surface.
The term "Abspanngraben" thus means the usual in the field of upholstery of seats term with its corresponding semantic content.

The following example serves to illustrate the invention.

In the drawings show:

FIG. 1 - A sketchy plan view of a particular embodiment of the heating element according to the invention.

In FIG. 1 is a sketch of a plan view of a particular embodiment of the heating element according to the invention shown.

The heating element essentially has a multiplicity of mutually parallel mesh threads 2 into which a heating conductor 1 is inserted sinusoidally. In each case three parallel current-supplying contact conductor 3 form a contact strip 4. The heating conductor 1 extends over a section S parallel to a contact conductor 3, then crosses the adjacent contact conductor 3, to finally run parallel to it again; Heating conductor 1 and contact conductor 3 are electrically connected together.

Heating conductor 1 and contact conductor 3 consist of several strand strands, which in turn consist of seven core-sheath wires. The wires have a core of a stainless steel according to DIN 4401 and a sheath of copper, wherein the core and sheath cross-sectional area have the same size.

Claims (12)

1. Arrangement comprising electrical heating elements of seat parts, the heating elements being configured with at least one heating conductor (1) and/or contact conductor (3), and the heating elements being isolated from one another and connected electrically to one another, the electrical connection being configured with a bridge litz wire, the bridge litz wire and the heating conductor (1) and/or contact conductor (3) of the heating elements being characterized by the fact that they have at least one litz wire with at least one core/cladding wire,

   a) the cladding consisting of a steel and the core consisting of copper or a copper alloy, or

   b) the cladding consisting of copper or a copper alloy and the core consisting of a steel.
2. Arrangement according to Patent Claim 1, wherein the bridge litz wire is the heating conductor.
3. Arrangement according to Patent Claim 1 or 2, wherein the bridge litz wire is the contact conductor.
4. Arrangement according to one of the preceding patent claims, wherein the litz wire of the heating element is fastened on a foam body and/or a knitted fabric, in particular by means of partial or short weft, and the bridge litz wire is highly flexible.
5. Arrangement according to Patent Claim 4, wherein the litz wire of the heating element is sewn on and/or sewn over.
6. Arrangement according to one of the preceding patent claims, wherein the steel is a carbon-containing steel and/or the steel is a stainless steel pursuant to DIN 4401.
7. Arrangement according to one of the preceding patent claims, wherein the copper alloy contains copper and nickel, the copper alloy preferably consisting of 90-10 weight% of copper and 10-90 weight% of nickel.
8. Arrangement according to one of the preceding patent claims, wherein the core and the cladding have cross-sectional areas with a ratio of 1:3 to 3:1, in particular the core and cladding have at least approximately the same cross-sectional areas.
9. Arrangement according to one of the preceding patent claims, wherein the wire diameter is 0.01-0.5 mm.
10. Arrangement according to one of the preceding patent claims, wherein the wire has outer electrical insulation, preferably insulation consisting of PTFE, FEP, MFA or polyurethane lacquer.
11. Arrangement according to one of the preceding patent claims, wherein the litz wire contains at least one left-hand litz wire strand and at least one right-hand litz wire strand, the number of left-hand litz wire strands and the number of right-hand litz wire strands preferably being the same.
12. Seat, in particular motor vehicle seat, having an arrangement according to one of the preceding patent claims, wherein said seat has seat components that are separated from one another by a tensioning trench, and there are electrical heating elements of seat components which are divided by the tensioning trench of the seat and which are connected to one another electrically by the bridge litz wire.

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