Patent Application
20200076105
This application claims the benefit of the filing date under 35 U.S.C. § 119(a)-(d) of German Patent Application No. 102018215025.7, filed on Sep. 4, 2018.
The present invention relates to an electrical contact and, more particularly, to an electrical contact adapted to connect to an aluminum conductor.
Copper contacts made of copper or a copper alloy are used to connect an electrical conductor to a mating contact. These copper contacts have a high weight and high material costs. However, in particular in the automobile industry, especially in the case of large conductor cross-sections as are required in electric vehicles, a low weight is desirable. Therefore, copper conductors, for example copper cables, are increasingly being replaced by aluminum conductors made of aluminum or an aluminum alloy.
The copper contact remains desirable due to the mechanical stability of copper in order to generate a necessary contact normal force with the mating contact. The linking of the copper contact to the aluminum conductor, however, is very difficult. In the case of electrical contacts with a high material thickness, great difficulties have arisen, in particular with the copper contacts, when preparing the contact for the connection to the aluminum conductor. Galvanically coating the copper contact with high material thickness is costly.
An electrical contact for mating with a mating contact includes an aluminum body extending along a longitudinal axis and formed of an aluminum or an aluminum alloy, a contact zone disposed on a surface of the aluminum body and adapted to be electrically connected to a mating contact, and a contact spring connected to the aluminum body and having a contact region contacting the mating contact. The aluminum body has a connecting portion adapted to be connected to an aluminum conductor. The contact zone is formed from a material that is more creep-resistant than the aluminum body. The contact spring at least partially rests on the contact zone and is formed from a material that is harder than the aluminum body.
The invention will now be described by way of example with reference to the accompanying Figures, of which:
Embodiments of the present invention will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to like elements. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the disclosure will convey the concept of the invention to those skilled in the art.
An electrical contact 1 according to an embodiment is shown in
The electrical contact 1, as shown in
In an embodiment, as shown in
As shown in
As shown in
The aluminum conductor 6 can, for example, be an aluminum cable 21 made of aluminum or an aluminum alloy. The aluminum cable 21, in an embodiment, has up to 99.7% aluminum.
As shown in
The contact zones 10 are formed from a material that is more creep-resistant than the aluminum body 2. In the shown embodiment, the contact zones 10 are made of a noble metal 32, such as a silver 34 and applied onto the surface 8 by roll-cladding. The contact zone 10 can alternatively be made of an alloy of a noble metal 32, such as a silver alloy. In other embodiments, the contact zone 10 can be formed from other noble metals 32 or noble metal 32 alloys such as gold or gold alloys or palladium or palladium alloys. Through the use of a contact zone 10 made of a noble metal or a noble metal alloy, surface corrosion on the contact zone 10, which can lead to a reduction in the electrical conductivity, is avoided. Alternatively, the contact zone 10 can be formed from tin or tin alloys, in particular in the case of applications in the lower temperature range, i.e. below approximately 120° C.
In order to save on the costs for the relatively expensive material of the contact zone 10, an intermediate layer 36 made of copper or a copper alloy is arranged between the contact zone 10 and the surface 8 in the height direction H, as shown in
With the intermediate layer 36, the application of the contact zone 10 can be simplified since the composition and material thickness of the intermediate layer 36 can be optimized. Furthermore, the intermediate layer 36 can prevent the aluminum from the aluminum body 2 from creeping into the contact zone 10. Furthermore, through a shaping of the contact zone 10 from a noble metal, a surface corrosion, which can lead to a reduction in the electrical conductivity, can be prevented. The contact zone 10 is arranged along the longitudinal axis L flush with the surface 8, as a result of which no undesired abrasion and resulting increased wear occurs at the transition between the surface 8 and the contact zone 10 when sliding along the longitudinal axis L. In an embodiment, the material thickness of the contact zone 10 can be between approximately 2 μm and approximately 10 μm thick and the material thickness of the intermediate layer 36 can be between approximately 10 μm and approximately 20 μm thick.
The contact springs 12, as shown in
As shown in
At one side 41 of the sleeve 40 arranged in the height direction H, a pair of undulating contact springs 12 extends away in the direction of the connecting portion 4 and are curved around the free end 18 and protrude into the socket cavity 22, as shown in
The contact springs 12 are made of a material that is mechanically and thermally more relaxation-resistant and stable than the aluminum or the aluminum alloy, for example stainless steel or copper, such as a copper alloy. The material of the contact spring 12 is harder than the aluminum body 2. The contact springs 12, as shown in
When a mating contact 16 is plugged in, the flow of current is conducted from the mating contact 16 via the contact springs 12 to the contact zone 10 and absorbed by the contact zone 10. Through the creep resistance of the contact zone 10, wear due to creepage is reduced. According to the exemplary configuration, the contact zone 10 is formed from silver, as a result of which surface corrosion, which could impair the electrical conductivity of the contact zone 10, is avoided. The flow of current is then guided from the contact zone 10 via the aluminum body 2 to the aluminum conductor 6. The contact normal force for contacting the mating contact 16 is generated by the contact springs 12, as a result of which the contact normal force with which the mating contact 16 is contacted is not generated by the aluminum body 2.
Through the plugging-in of the mating contact 16, the contact springs 12 are elastically deflected between the contact region 14 and the contact zone 10 and pressed against the contact zone 10. The contact zone 10 is made of a mechanically robust material, such as a noble metal, for example, as a result of which the contact zone 10 can withstand the pressing force of the contact springs 12 without yielding and is not abraded by a friction between the contact springs 12 on the contact zone 10 arising as a result of a relative movement.
With the electrical contact 1, particularly simple linking between the aluminum conductor 6 and the contact 1 is possible, without any additional processing of the contact 1 prior to the connecting. Since both components are made substantially from the same material, it is possible to connect the aluminum conductor 6 directly to the contact 1 without risking contact corrosion. Because the contact 1 has an aluminum body 2 with a connecting portion 4 for connecting to the aluminum conductor 6, it is possible to avoid difficulties even in the case of an electrical contact 1 with high material thickness. With the contact 1, a more lightweight alternative which is inexpensive compared to the copper contacts known from the prior art is created due to the lower material costs and mass of aluminum compared to copper. The aluminum body 2 leads to savings in terms of weight and material costs compared to the currently known electrical contacts, for example, copper contacts.
The contact to the mating contact 16 is generated via the at least one contact spring 12, as a result of which the aluminum body 2 is subjected to less strong mechanical stress. The flow of current is absorbed by the contact zone 10 via the at least one contact spring 12. Through the contact zone 10 which is more creep-resistant compared to the aluminum body 2, long-term contacting of the mating contact 16 can be achieved without loss of the contact quality and the wear on the electrical contact 1 can be reduced.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102018215025.7 | Sep 2018 | DE | national |
