Connectors offer space for switching technology
by Norbert Witteczek |
Some time ago, we already reported here on the replication of connectors. In the automotive sector, connectors that are only designed for very few mating cycles are usually used for contacting control units. During tests, a few mating cycles are quickly completed. Each time the connector is plugged in and unplugged, the blade or pin of one connector part rubs against the spring contacts of the other and removes some of the contact layer, which is usually very thin on these connectors. The result is increased contact resistance, which on the one hand distorts the test result, but on the other hand can also become a source of error itself.
In the most recent project of this kind, in addition to the use of contacts that allow a very high number of mating cycles, a whole range of other requirements were added that demanded all our design know-how. The task was: Design a connector for testing a radar control unit that does not damage the contacts of the control unit even with many mating cycles and contains both a small patch field and a relay conductor card.
Here, too, we achieve the high number of mating cycles by using ODU SPRINGTAC flat plug contacts with wire spring technology. Instead of a thick spring, these contacts work with many very thin springs that generate hardly any friction. The manufacturer guarantees 50,000 mating cycles for the type used, without the mating part being affected during mating. The customer can therefore be sure that no damage will occur to the contacts of the control unit when testing the components. We moulded the chambers for the contacts, like the entire connector housing, using the 3D printing process. This is not trivial, because 3D printing has resolution limits that we come up against in this task. One or two recursion loops should therefore be planned for.
Of course, when designing the housing, care must also be taken to ensure that the plug is easily and intuitively plugged into the control unit the right way round at the end and that the polarisation is correct. Coding lugs ensure this.
The small patcharea allows the customer to change the wiring inside the connector over time.
Relay circuit board makes the plug intelligent
The connector becomes really intelligent through the relay circuit board that is also installed, or rather through the different circuit boards. Our customer uses not just one, but several variants. Depending on the variant used, the cross-section of the cables leading into the connector also changes. This meant another design challenge for us, because the cable strain relief must also be able to accommodate variable cross-sections.
We have mastered this requirement by means of a cable strain relief in the cable strain relief, whereby the inner strain relief is captive but movable connected to the two outer cable strain reliefs and these in turn are captive connected to the housing. All in all, the entire connector consists of only three parts. Ergonomic ribbing on the housing facilitates plugging in and unplugging.
Of course, you could also integrate various other elements into such a connector, for example LEDs that signal certain switching states. Many things are possible, just contact me, preferably by e-mail to norbert.witteczek@smart-ts.de.
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