Electrical contact element for high operating voltage
Patent Information
- Application Number
- JP2025021988
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2019-06-05
- Filing Date
- 2025-02-14
- Publication Date
- 2025-09-01
AI Technical Summary
Existing electrical contact elements for connectors operating at voltages exceeding 150V are costly due to the use of expensive noble metals like gold-cobalt alloys or palladium-nickel alloys, which are required to prevent metal migration and ensure reliability and service life.
The use of a nickel-phosphorus alloy as the wear layer in electrical contact elements, which provides good current transmission and corrosion protection similar to noble metal alloys, but at a lower cost. This alloy is applied directly to the substrate or with an intermediate layer, and can be combined with a thin slide layer for improved sliding properties.
The nickel-phosphorus alloy wear layer achieves comparable performance to conventional noble metal alloys in terms of corrosion resistance and electrical transmission, while significantly reducing material costs and usage, and allowing for a thinner wear layer design.
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Abstract
Description
Technical Field
[0001] The present invention relates to an electrical contact element for a connector suitable for an electrical operating voltage exceeding 150V.
Background Art
[0002] Electrical connectors generally have one or more electrical contact elements and one or more insulators. The contact elements are usually designed as male or female elements. These are generally made of a base material that is not corrosion-resistant. These are often copper alloys. Therefore, in order to ensure the function of the contact elements over the service life of the connector, a thin layer of another metal is applied to the base material. These can comprise an intermediate layer and a wear layer.
[0003] The intermediate layer can have various purposes. It can improve the adhesion of the wear layer to the base material, create a mechanical balance between the base material and the wear layer, and prevent a diffusion process from occurring between the wear layer and the base material. The intermediate layer often consists of copper or nickel.
[0004] The wear layer, also referred to as the functional layer, is located on the intermediate layer. The wear layer can extend the technically useful life of the contact element, improve electrical transmission, and protect the underlying layer from corrosion. It can consist of a soft non-inert metal, such as tin or silver. In connectors in the automotive field, for example, silver is widely used as a wear layer. When a voltage exceeding 150V occurs in an application, the potential force between different contact elements can gradually excite metal ions and move them from one physical location to another. This metal migration can cause short circuits and other technical problems in the connector. The functional surface of silver has a tendency for this type of metal migration at higher voltages. For this reason, a more expensive noble metal functional layer is usually used in applications having an operating voltage exceeding 150V. Thus, for example, a gold cobalt alloy or a palladium-nickel alloy is used.
Summary of the Invention
Problems to be Solved by the Invention
[0005] An object of the present invention is to provide an electrical contact element suitable for use in an electrical connector and suitable for an electrical operating voltage exceeding 150V. However, it must be possible to manufacture it at a cost lower than that of conventional electrical contact elements while still achieving the reliability and service life of conventional electrical contact elements.
Means for Solving the Problems
[0006] This object is solved by an electrical contact element for a connector having a metallic substrate or a wear layer applied to the substrate. The wear layer can be applied directly to the metallic substrate or one or more additional layers can be arranged between the metallic substrate and the wear layer. The wear layer consists of the following alloy elements, namely 82 to 91% by weight of nickel, 9 to 18% by weight of phosphorus and 0 to 1% by weight of further alloy elements. Preferably, the layer consists of 82 to 89% by weight of nickel, 11 to 18% by weight of phosphorus and 0 to 1% by weight of further alloy elements. The total of the alloy elements is 100% by weight. The proportion of up to 1% by weight of further alloy elements in the alloy is, for example, accepted as impurities, but it is preferably avoided. According to the present invention, it has been found that the use of this type of wear layer provides good current transmission and good corrosion protection similar to that achievable by wear layers made of, for example, gold-cobalt alloys or palladium-nickel alloys. However, the use of nickel-phosphorus alloys makes it possible to manufacture electrical contact elements more cost-effectively by comparison.
[0007] In a preferred embodiment of the present invention, the wear layer is disposed directly on the substrate, and there is no additional layer between the wear layer and the substrate. In order to ensure good corrosion prevention, in this embodiment, it is preferable that the wear layer has a thickness in the range of 1.00 μm to 2.50 μm. Particularly preferably, the thickness is in the range of 1.50 μm to 2.00 μm. Since the wear layer used according to the present invention provides this kind of good protection against corrosion and this kind of good electrical transmission, these properties cannot be significantly improved by further increasing the layer thickness. On the other hand, when using a conventional wear layer of a gold-cobalt alloy or a palladium-nickel alloy, in order for the electrical contact element to meet the requirements of corrosion resistance and electrical transmission, a metal intermediate layer is used simultaneously, and usually a layer thickness of at least 3 μm is required. Therefore, the present invention not only enables the manufacture of electrical contact elements using lower-cost materials, but also enables the reduction of the amount of material, particularly by using a particularly thin wear layer.
[0008] In another preferred embodiment of the present invention, the metal intermediate layer is disposed between the substrate and the wear layer. Particularly preferably, the intermediate layer is disposed between the wear layer and the substrate such that the substrate is directly connected to the intermediate layer and the intermediate layer is directly connected to the wear layer, and it is the only layer disposed between the wear layer and the substrate. Like the conventional design of electrical contact elements, the intermediate layer improves the adhesion of the wear layer to the substrate, ensures mechanical compensation between the substrate and the wear layer, and prevents the diffusion process between the wear layer and the substrate. In addition, the intermediate layer enables the use of a thinner wear layer compared to the embodiment of the present invention where the wear layer is disposed directly on the substrate. In this embodiment, the wear layer preferably has a thickness in the range of 0.15 μm to 1.50 μm. Particularly preferably, the thickness is in the range of 0.30 μm to 1.00 μm.
[0009] In one embodiment of the contact element, the intermediate layer comprises 99 to 100 wt% copper and 0 to 1 wt% of further alloying elements. In another preferred embodiment of the contact element, the intermediate layer comprises 99 to 100 wt% nickel and 0 to 1 wt% of further alloying elements. Thus, the total of the alloying elements is 100 wt%. The proportion of the further alloying elements should preferably be as low as possible, but due to impurities, their presence cannot be completely excluded.
[0010] The thickness of the intermediate layer is preferably from 1.5 μm to 4.0 μm, particularly preferably from 2.0 μm to 3.0 μm.
[0011] Furthermore, it is preferred that a metal and / or organic slide layer is arranged on the wear layer. The slide layer can improve the sliding properties of the electrical contact elements, in particular the female and male elements. In this way, it helps the wear layer to remain functional longer under mechanical frictional stress. On the other hand, it can also optimize the electrical transmission between the electrical contact elements. If the slide layer contains both a metal component and an organic component, it is preferred that the metal sub-layer is applied directly to the wear layer and the organic sub-layer is applied to this metal sub-layer. The metal sub-layer and the organic sub-layer then together form the slide layer.
[0012] A particularly suitable metal material for the slide layer is pure gold or a gold alloy consisting of the following alloying elements, namely 98.5 to 100.0 wt% gold, 0 to 0.5% cobalt and 0 to 1.0 wt% of further alloying elements. The total of the alloying elements is 100 wt%.
[0013] Particularly suitable organic materials for the slide layer are at least one fluoropolymer and / or at least one fatty acid salt. The fluoropolymer can be, for example, perfluoropolyether (PFPE) or polytetrafluoroethylene (PTFE). The fatty acid salt can be, for example, lithium-12-hydroxystearate.
[0014] The thickness of the sliding layer is preferably in the range from 0.05 μm to 0.25 μm. Since this type of sliding layer is already sufficient to impart good sliding properties to the electrical contact element, applying the sliding layer to the wear layer does not, as a result, lead to a significant increase in the overall thickness of the coating.
[0015] The wear layer of the electrical contact element according to the invention can be used particularly advantageously if the substrate is made of copper, a low-alloy copper alloy or brass. In this case, it consists of the following alloy elements, namely from 50 to 100% by weight of copper, from 0 to 45% by weight of zinc and from 0 to 5% by weight of further alloy elements. In this case, the sum of the alloy elements is 100% by weight. In the present specification, even if the sum of the further alloy elements can be up to 5% by weight, it is preferred that each individual further alloy element constitutes not more than 2% by weight of the total alloy. Furthermore, only beryllium, chromium, iron, cobalt, magnesium, manganese, nickel, phosphorus, sulfur, silver, silicon, tellurium, titanium, tin and zirconium of the other alloy elements can be present in the alloy in an amount of up to 2% by weight each, and it is preferred that all other alloy elements not mentioned in this list are present in an amount of not more than 1% by weight in each case.
[0016] The electrical contact element according to the invention can be manufactured with good technical properties without the need to use large amounts of expensive precious metals.
[0017] Exemplary embodiments of the invention are depicted in the drawings and are explained in more detail in the following description.
Brief Description of the Drawings
[0018]
Figure 1
Figure 2
Figure 3
Figure 4
[0019] FIG. 1 shows the schematic structure of a pair of connectors. The first connector 10 has an electrical contact element 11 in the form of a male element. This is surrounded by a first insulator 12 made of plastic. The second connector 20 has a second electrical contact element 21 in the form of a female element. This is surrounded by a second insulator 22 made of plastic. When the two connectors 10, 20 are connected to each other in the manner shown, the second insulator 22 is pushed into the first insulator 12, and the first electrical contact element 11 slides into the second electrical contact element 21. At this time, it bends away from the tongue of the second contact element 21, and then the tongue is fixedly pressed onto the first contact element 11 by their spring force. Next, power transmission is possible in the contact region 30 where the two contact elements 11, 21 are in contact.
[0020] In electrical connectors 10, 20 having contact elements 11, 21 according to the prior art, the structure of the contact elements 11, 21 depicted in FIG. 2 exists in the contact region 30. The first contact element 11 has a base 111, an intermediate layer 112 disposed on the base, and a wear layer 113 disposed on the intermediate layer. The second contact element 21 has a base 211, an intermediate layer 212 disposed on the base 211, and a wear layer 213 disposed on the intermediate layer 212. The bases 111, 211, the intermediate layers 112, 212, and the wear layers 113, 213 each have a composition of weight percentages shown in Table 1. **Table 1**
[0021] In this example, the intermediate layers 112, 212 each have a thickness d of 3 μm 112 , d 212has wear layers 113, 213 each having a thickness d of 4 μm 113 , d 213 The wear layers 113, 213 contact each other in the contact region 30. The large amount of gold-cobalt alloy required for manufacturing the wear layers results in high manufacturing costs for the electrical contact elements 11, 21.
[0022] FIG. 3 shows the structure of the electrical contact elements 11, 21 according to some exemplary embodiments of the present invention, which can be used in pairs of connectors 10, 20 according to FIG. 1. In addition to the structure of the electrical contact elements 11, 21 consisting of the substrates 111, 211, the intermediate layers 112, 212 and the useful layers 113, 213 already depicted in FIG. 2, the contact elements 11, 21 according to these exemplary embodiments of the present invention also have slide layers 114, 214 on their wear layers 113, 213. As a result, contact between the wear layers 113, 213 does not occur in the contact region 30, but rather leads to contact between the slide layers 114, 214. The thickness of the intermediate layers 112, 212 in the exemplary embodiments of the present invention corresponds to the thickness of the intermediate layers 112, 212 in the comparative examples, but the exemplary embodiments according to the present invention make do with substantially thinner wear layers 113, 213, in each case with a thickness d 113 , d 213 which is only 0.65 μm. As a result, this leads to a significant reduction in material compared to the comparative examples. In the embodiments according to the present invention, the slide layers 114, 214 each have a thickness d 114 , d 214 of 0.10 μm. Thus, each wear layer 113, 213 is thinner than the wear layers 113, 213 of the comparative examples even when combined with its respective slide layer 114, 214.
[0023] In a first exemplary embodiment of the present invention, the components of the contact elements 11, 21 have a composition in weight percentages listed in Table 2.
Table 2
[0024] Thus, in the comparative example, the intermediate layer made of pure silver is made of a nickel-phosphorus alloy in the first exemplary embodiment. This results in cost reduction not only because less metal is used for the wear layer, but also due to the use of a lower-cost alloy.
[0025] The slide layers 114, 214 are made of the same gold-cobalt alloy as the wear layers 113, 213 of the comparative example. Therefore, the sliding characteristics of the contact elements 11, 21 in the comparative example and the first exemplary embodiment of the present invention are equally good. However, since the slide layers 114, 214 are very thin compared to the wear layers 113, 213 of the comparative example, most of the expensive gold-cobalt alloy can be reduced.
[0026] In the second exemplary embodiment of the electrical contact elements 11, 21, their components have the composition of weight percentages shown in Table 3.
Table 3
[0027] Compared with the first exemplary embodiment, the metal slide layers 114, 214 are each replaced by an organic slide layer made of PTFE. In the third exemplary embodiment, by omitting the expensive noble metals, nevertheless, excellent sliding characteristics of the contact elements 11, 21 can be achieved, and nevertheless, it has been found that the electrical transmission is not worse than that of the electrical contact elements 11, 21 of the comparative example.
[0028] In the third exemplary embodiment of the present invention, since the intermediate layers 112, 212 are omitted, the contact elements 11, 21 have the structure depicted in FIG. 4, and the wear layers 113, 213 are directly disposed on the substrates 111, 211 in each case. In each case, in contrast to the previous exemplary embodiments, the thickness d 113 、d 213 of the wear layers 113, 213 is 1.50 μm. The components of the contact elements 11, 21 have the composition of weight percentages listed in Table 4.
Table 4
[0029] Thus, by using a wear layer thicker than that of the first and second exemplary embodiments of the present invention, the contact elements 11, 21 can be manufactured without using the intermediate layers 112, 212. Here, wear layers 113, 213 thicker than those of the first two exemplary embodiments are used, but these are still significantly thinner than the wear layers 113, 213 of the comparative examples.
[0030] In the fourth exemplary embodiment of the present invention, just as the slide layers 114, 214 of the first exemplary embodiment are replaced by PTFE of the second exemplary embodiment, the slide layers 114, 214 of the contact elements 11, 21 of the third exemplary embodiment are also replaced by organic slide layers each made of PTFE. Next, the components of the electrical contact elements 11, 21 have a composition in weight percentages as shown in Table 5.
Table 5
[0031] All five described exemplary embodiments of the electrical contact elements 11, 21 according to the present invention enable a cost-effective replacement of the electrical contact elements 11, 21 according to the comparative examples without leading to impairments of the properties associated with the contact elements 11, 21, and they are suitable for electrical operating voltages above 150V.
Claims
1. An electrical contact element (11, 21) for a connector (10, 20) having a metallic substrate (111, 211) and a wear layer (113, 213) applied to said substrate (111, 211), said wear layer (113, 213) being made of the following alloying elements: 82 to 91 wt. % nickel, 9 to 18 wt. % phosphorus; 0-1 wt. % of further alloying elements, The sum of the alloy elements is 100% by weight, and an organic sliding layer (114, 214) comprising at least one fluoropolymer and / or at least one fatty acid salt is coated directly on the wear layer (113, 213), the sliding layer (114, 214) having a thickness (d 114 , d 214 ) in the range of 0.05 μm to 0.10 μm.
2. 2. The electrical contact element (11, 21) according to claim 1, characterized in that the wear layer (113, 213) is arranged directly on the substrate (111, 211).
3. The wear layer (113, 213) has a thickness (d １１３ , d ２１３ 3. The electrical contact element (11, 21) according to claim 2, characterized in that it has a
4. 2. Electrical contact element (11, 21) according to claim 1, characterized in that an intermediate layer (112, 212) of metal is arranged between the substrate (111, 211) and the wear layer (113, 213).
5. The intermediate layer (112, 212) comprises the following alloying elements: 99 to 100% by weight of copper or nickel, 0-1 wt. % of further alloying elements, 5. Electrical contact element (11, 21) according to claim 4, characterized in that the sum of said alloying elements is 100% by weight.
6. The intermediate layer (112, 212) has a thickness (d １１２ , d ２１２ 6. Electrical contact element (11, 21) according to claim 4 or 5, characterized in that it comprises a
7. The wear layer (113, 213) has a thickness (d １１３ , d ２１３ 7. An electrical contact element (11, 21) according to claim 3, characterized in that it has a
8. The substrate (111, 211) contains the following alloying elements: 50 to 100% by weight of copper, 0 to 45% by weight of zinc, 0-5 wt. % of further alloying elements, 8. Electrical contact element (11, 21) according to any of claims 1 to 7, characterized in that the sum of the alloying elements is 100% by weight.