DE202019103166U1 - Electrical contact element - Google Patents

Abstract

wobei die Summe der Legierungselemente 100 Gew.-% beträgt.

Electrical contact element (11, 21) for a plug connector (10, 20), comprising a metallic base body (111, 211) and a wear layer (113, 213) applied to the base body (111, 211), characterized in that the wear layer ( 113, 213) consists of the following alloying elements: 50-100% by weight Ruthenium 0 - 30% by weight nickel 0 - 20% by weight chrome 0 - 20% by weight Cobalt 0 - 20% by weight platinum 0-1% by weight further alloying elements the sum of the alloying elements being 100% by weight.

Description

The present invention relates to an electrical contact element for a connector.

State of the art

Electrical connectors generally have one or more electrical contact elements and one or more insulating bodies. The contact elements are usually designed as knife elements or as spring elements. These are made from base materials that are not resistant to corrosion. These are often copper alloys. In order to ensure the function of the contact elements over the life of the connector, thin layers of other metals are therefore applied to the base material. These can include an intermediate layer and a wear layer.

The intermediate layer can have different tasks. It can improve the adhesion of the wear layer to the base material, establish a mechanical balance between the base material and the wear layer and prevent diffusion processes from taking place between the wear layer and the base material. The intermediate layer is often made of copper or nickel.

The wear layer, which is also referred to as the functional layer, is located on the intermediate layer. The wear layer extends the technically sensible service life of the contact element, can improve the electrical transmission and protect the layers underneath from corrosion. It can consist of soft, non-inert metals such as tin or silver. Silver, for example, is widely used as a wear layer in connectors in the automotive sector. In plug-in systems with particularly high demands on reliability and service life, wear layers made of very expensive, corrosion-resistant precious metals or their alloys are often used. For example, gold-cobalt alloys or palladium-nickel alloys are used.

It is an object of the present invention to provide an electrical contact element which is suitable for use in an electrical connector and can be produced more cost-effectively than conventional electrical contact elements. The reliability and service life of conventional electrical contact elements should nevertheless be achieved.

Disclosure of the invention

This object is achieved by an electrical contact element for a plug connector, which has a metallic base body or a wear layer applied to the base body. The wear layer can be applied directly to the metallic base body or one or more further layers can be arranged between the metallic base body and the wear layer. The wear layer consists of the following alloy elements: 50 to 100 wt.% Ruthenium, 0 to 30 wt.% Nickel, 0 to 20 wt.% Chromium, 0 to 20 wt.% Cobalt, 0 to 20 wt. % Platinum and 0 to 1% by weight of further alloying elements. The sum of the alloy elements is 100% by weight. The wear layer can therefore consist both of pure ruthenium and of a ruthenium alloy, which can contain up to 50% further alloy elements. While nickel, chromium, cobalt and platinum can be added in the stated proportions, proportions of further elements are preferably avoided. However, a proportion of up to 1% by weight of further alloy elements in the alloy, for example as impurities, is acceptable. In one embodiment of the electrical contact element, in which the wear layer consists essentially of pure ruthenium, it contains 99 to 100% by weight and a maximum of 1% by weight of further alloy elements, the total of the alloy elements again being 100% by weight. According to the invention, it was found that the use of such a wear layer offers a similarly good electrical transmission and a similarly good corrosion protection as can be achieved, for example, with the wear layer made of silver. However, the use of pure ruthenium or the described ruthenium alloy enables the electrical contact element to be produced more cheaply in comparison to this.

In order to ensure good corrosion protection, it is preferred that the wear layer has a thickness in the range from 0.15 μm to 1.50 μm. The thickness is particularly preferably in the range from 0.30 μm to 1.00 μm. The wear layer used according to the invention offers such good protection against corrosion and such good electrical transmission that these properties could no longer be significantly improved by a further increase in the layer thickness. On the other hand, when using a conventional wear layer made of silver, for example, a layer thickness of at least 3 μm is usually required in order for the electrical contact element to meet the requirements for corrosion resistance and electrical resistance Transfer accomplished. The invention accordingly not only makes it possible to produce the electrical contact element using less expensive materials, but also to save the amount of material by using a particularly thin wear layer.

It is preferred that a metallic intermediate layer is arranged between the base body and the wear layer. The intermediate layer is particularly preferably the only layer which is arranged between the wear layer and the base body, so that the base body is connected directly to the intermediate layer and the intermediate layer is connected directly to the wear layer. As in the conventional structure of the electrical contact element, the intermediate layer improves the adhesion of the wear layer to the base body, ensures a mechanical balance between the base body and the wear layer and prevents diffusion processes between the wear layer and the base body.

In one embodiment of the contact element, the intermediate layer contains 99 to 100% by weight of copper and 0 to 1% by weight of further alloy elements. In another preferred embodiment of the contact element, the intermediate layer contains 99 to 100% by weight of nickel and 0 to 1% by weight of further alloy elements. The sum of the alloy elements is 100% by weight. The proportion of the further alloying elements should preferably be as small as possible, however their presence due to impurities may not be completely excluded.

The thickness of the intermediate layer is preferably 1.5 μm to 4.0 μm and particularly preferably 2.0 μm to 3.0 μm.

It is further preferred that a metallic and / or organic sliding layer is arranged on the wear layer. On the one hand, the sliding layer can improve the sliding properties of electrical contact elements, in particular spring elements on knife elements. This means that the wear layer remains functional for longer under mechanical frictional stress. On the other hand, it can also optimize the electrical transmission between the electrical contact elements. If the sliding layer contains both metallic and organic components, then it is preferred that a metallic partial layer is applied directly to the wear layer and an organic partial layer is applied to this metallic partial layer. The metallic partial layer and the organic partial layer then together form the sliding layer.

A particularly suitable metallic material for the sliding layer is pure gold or a gold alloy, which consists of the following alloy elements: 98.5 to 100.0% by weight of gold, 0 to 0.5% by weight of cobalt and 0 to 1, 0% by weight of further alloying elements. The sum of the alloy elements is 100% by weight.

Particularly suitable organic materials of the sliding layer are at least one fluoropolymer and / or at least one fatty acid salt. The fluoropolymer can be, for example, a perfluoropolyether (PFPE) or polytetrafluoroethylene (PTFE). The fatty acid salt can be, for example, lithium 12-hydroxystearate.

The thickness of the sliding layer is preferably in the range from 0.05 μm to 0.25 μm. Such thin sliding layers are sufficient to give the electrical contact element good sliding properties, so that the application of the sliding layer to the wear layer does not result in a significant increase in the thickness of the entire coating.

The wear layer of the electrical contact element according to the invention can be used particularly advantageously when the base body consists of copper, a low-alloy copper alloy or brass. In this case, it consists of the following alloying elements: 50 to 100% by weight of copper, 0 to 45% by weight of zinc and 0 to 5% by weight of further alloying elements. The sum of the alloy elements is 100% by weight. Even if the sum of the further alloy elements here can be up to 5% by weight, it is preferred that each individual further alloy element makes up no more than 2% by weight of the total alloy. Furthermore, it is preferred that only the further alloy elements beryllium, chromium, iron, cobalt, magnesium, manganese, nickel, phosphorus, sulfur, silver, silicon, tellurium, titanium, tin and zirconium in each case up to 2% by weight in the Alloy may be included and all other alloy elements not mentioned in this list are present at a maximum of 1% by weight.

The electrical contact element according to the invention can be produced with good technical properties without having to use large amounts of expensive precious metals.

Figure list

• 1 zeigt eine schematische Längsschnittdarstellung durch eine Anordnung aus zwei elektrischen Steckverbindern.
• 2 zeigt eine Querschnittsdarstellung eines Kontaktbereichs zwischen zwei elektrischen Kontaktelementen in einem Vergleichsbeispiel.
• 3 zeigt eine Querschnittsdarstellung eines Kontaktbereichs von zwei elektrischen Kontaktelementen gemäß Ausführungsbeispielen der Erfindung.

Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the description below.

• 1 shows a schematic longitudinal sectional view through an arrangement of two electrical connectors.
• 2nd shows a cross-sectional view of a contact area between two electrical contact elements in a comparative example.
• 3rd shows a cross-sectional view of a contact area of two electrical contact elements according to embodiments of the invention.

Embodiments of the invention

1 shows the schematic structure of a connector pair. A first connector 10th has an electrical contact element 11 in the form of a knife element. This is from a first insulation body 12th surrounded by a plastic. A second connector 20 has a second electrical contact element 21 in the form of a spring element. This is from a second insulation body 22 surrounded by a plastic. If the two connectors 10th , 20 are inserted into each other in the manner shown, then the second insulation body 22 in the first insulation body 12th pushed, the first electrical contact element 11 in the second electrical contact element 21 slides in. It bends the springs of the second contact element 21 apart, which then firmly by their spring force on the first contact element 11 be pressed. In a contact area 30th in which the two contact elements 11 , 21 electrical transmission is then possible.

In electrical connectors 10th , 20 who have favourited Contact Elements 11 , 21 according to the prior art, is in 2nd shown structure of the contact elements 11 , 21 in the contact area 30th in front. The first contact element 11 has a body 111 , an intermediate layer arranged on the base body 112 and a wear layer arranged on the intermediate layer 113 on. The second contact element 21 has a body 211 , one on the main body 211 arranged intermediate layer 212 and one on the intermediate layer 212 arranged wear layer 213 on. The basic body 111 , 211 , the intermediate layers 112 , 212 and the wear layers 113 , 213 each have the composition stated in Table 1 in percent by weight: Table 1 Basic body Intermediate layer Wear layer 111, 211 112, 212 113, 213 Ag 100 Au Co Cu 100 Ni 100 Ru PTFE

In the present example, the intermediate layers 112 , 212 one thickness each d ₁₁₂ , d ₂₁₂ from 3 µm and the wear layers 113 , 213 each have a thickness d ₁₁₃ , d ₂₁₃ from 4 µm. The wear layers 113 , 213 touch in the contact area 30th , which can lead to an abrasion of silver. The large amount of silver that is required for the production of the wear layers leads to the production of the electrical contact elements 11 , 21 is expensive.

3rd shows the structure of the electrical contact elements 11 , 21 according to several embodiments of the invention included in the pair of connectors 10th , 20 according to 1 can be used. In addition to that already in 2nd shown structure of the electrical contact elements 11 , 21 from basic bodies 111 , 211 , Intermediate layers 112 , 212 and wear layers 113 , 213 point the contact elements 11 , 21 according to these embodiments of the invention on their wear layers 113 , 213 one sliding layer each 114 , 214 on. This leads to the contact area 30th no contacting of the wear layers 113 , 213 but contacting the sliding layers 114 , 214 is present. While the thickness of the intermediate layers 112 , 212 in the embodiments of the invention with the thickness of the intermediate layers 112 , 212 in the comparative example, the exemplary embodiments according to the invention come with significantly thinner wear layers 113 , 213 from whose thickness d ₁₁₃ , d ₂₁₃ is only 0.65 µm each. This leads to considerable material savings compared to the comparative example. The sliding layers 114 , 214 each have a thickness d ₁₁₄ , d ₂₁₄ of 0.10 μm in the exemplary embodiments according to the invention. Every wear layer 113 , 213 is itself together with their respective sliding layer 114 , 214 thinner than the wear layer 113 , 213 in the comparative example.

In a first embodiment of the invention, the components of the contact elements 11 , 21 the composition listed in Table 2 in percent by weight. Table 2 Basic body Intermediate layer Wear layer Sliding layer 111, 211 112, 212 113, 213 114.214 Ag Au 99.8 Co 0.2 Cu 100 Ni 100 Ru 100 PTFE

The intermediate layer, which in the comparative example consists of pure silver, therefore consists of pure ruthenium in the first embodiment. This leads to a cost saving, not only due to less used metal for the wear layer, but also due to the use of a less expensive metal. The sliding layer consists of an alloy of gold and cobalt, which enables excellent electrical transmission and, due to the softness of this alloy, has better sliding properties than the silver used in the comparative example. However, the sliding layer is so thin that, despite the noble metal used, there is no appreciable increase in the cost of the contact elements 11 , 21 leads.

In a second embodiment of the electrical contact elements 11 , 21 According to the invention, their constituents have the composition stated in Table 3 in percent by weight: Table 3 Basic body Intermediate layer Useful layer Sliding layer 111.112 112, 212 113, 213 114, 214 Ag Au 99.8 Co 0.2 Cu 100 Ni 100 Ru 100 PTFE

The pure ruthenium of the wear layers 113 , 213 according to the first embodiment, was replaced by a ruthenium-nickel alloy. It was found that even using such an alloy, the properties of the electrical contact elements according to the comparative example with regard to corrosion resistance and electrical transmission can still be achieved or even exceeded.

In a third embodiment of the electrical contact elements 11 , 21 their constituents have the composition in percent by weight stated in Table 4: Table 4 Basic body Intermediate layer Wear layer Sliding layer 111, 211 112, 212 113, 213 114, 214 Ag Au Co Cu 100 Ni 100 10th Ru 90 PTFE 100

Compared to the first embodiment, the metallic sliding layers 114 , 214 replaced by organic sliding layers, each made of PTFE. It was found that, without an expensive precious metal in the third exemplary embodiment, excellent sliding properties of the contact elements are nevertheless achieved 11 , 21 can be achieved, but the electrical transmission is still not worse than that of the electrical contact elements 11 , 21 in the comparative example.

All three described embodiments of the electrical contact elements 11 , 21 according to the invention enable an inexpensive replacement of the electrical contact elements 11 , 21 according to the comparative example, without this affecting the contact elements 11 , 21 relevant properties.

Claims (10)

Electrical contact element (11, 21) for a plug connector (10, 20), comprising a metallic base body (111, 211) and a wear layer (113, 213) applied to the base body (111, 211), characterized in that the wear layer ( 113, 213) consists of the following alloying elements: 50-100% by weight Ruthenium 0 - 30% by weight nickel 0 - 20% by weight chrome 0 - 20% by weight Cobalt 0 - 20% by weight platinum 0-1% by weight further alloying elements the sum of the alloying elements being 100% by weight. Electrical contact element (11, 21) after Claim 1 , characterized in that the wear layer (113, 213) has a thickness (d ₁₁₃ , d ₂₁₃ ) in the range from 0.15 µm to 1.50 µm. Electrical contact element (11, 21) after Claim 1 or 2nd , characterized in that a metallic intermediate layer (112, 212) is arranged between the base body (111, 211) and the wear layer (113, 213). Electrical contact element (11, 21) after Claim 3 , characterized in that the intermediate layer (112, 212) consists of the following alloy elements: 99 - 100% by weight Copper or nickel 0-1% by weight further alloying elements the sum of the alloying elements being 100% by weight. Electrical contact element (11, 21) after Claim 3 or 4th , characterized in that the intermediate layer (112, 212) has a thickness (d ₁₁₂ , d ₂₁₂ ) in the range from 1.5 µm to 4.0 µm. Electrical contact element (11, 21) according to one of the Claims 1 to 5 , characterized in that a metallic and / or organic sliding layer (114, 214) is arranged on the wear layer (113, 213). Electrical contact element (11, 21) after Claim 6 , characterized in that the sliding layer (114, 214) contains an alloy consisting of the following alloy elements: 98.5-100.0% by weight gold 0 - 0.5% by weight Cobalt 0 - 1.0% by weight further alloying elements the sum of the alloying elements being 100% by weight. Electrical contact element (11, 21) after Claim 6 or 7 , characterized in that the sliding layer (114, 214) contains at least one fluoropolymer and / or at least one fatty acid salt. Electrical contact element (11, 21) according to one of the Claims 6 to 8th , characterized in that the sliding layer (114, 214) has a thickness (d ₁₁₄ , d ₂₁₄ ) in the range from 0.05 µm to 0.25 µm. Electrical contact element (11, 21) according to one of the Claims 1 to 9 , characterized in that the base body (111, 211) consists of the following alloy elements: 50-100% by weight copper 0 - 45% by weight zinc 0 - 5% by weight further alloying elements the sum of the alloying elements being 100% by weight.

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