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Studies of connectors for electric and electronic automotive systems have been and still are being pursued. The electrical connector reliability mainly depends on the connector insertion force. This force is related to the contact force which is imposed by the connector design. A nonintrusive technique for contact force determination by deflection measurement of the contact spring during insertion phase using a laser device has been developed. The following insertion parameters during the insertion stroke can be measured: contact deflection which yields the contact force, insertion force, and contact resistance. Regarding the results for real connectors, an experimental sample of a connector based on a cylindrical pin crossed with a cylindrical spring is proposed in this paper. With this simple setup, an mathematical model was developed and permits analysis of the influence of each parameter (width, spring radius, etc). Based on analysis of the influence of the spring width and of the gap, this study offers the possibility of optimizing the design of such connectors for use in the automotive industry.

For automotive applications, the stability of the supplied electric power depends of the change of electrical resistance. For the case of automotive connectors, an electrical current goes through the connector wire and can be perturbed by the mechanical behaviour of the connector contact area under vibrations and temperature. Such vibrations on the bulk contact device are typically in the range of 10 Hz–2000 Hz and result in displacements of only a few microns at the contact interface. In the present study, a bench test has been developed to control motions down to 1μm. The objective is to determine the minimum amplitude for fretting-corrosion degradation based on the evolution of contact resistance and to study the effects of the temperature. It was found that the fretting degradation depends on vibration displacements, used materials, loading and applied temperature.

International audience; A connector provides a separable interface between two subsystems of an electronic system. The main function of the connector is to transmit a signal or distribute power. For power connectors, heating can lead to an increase in contact resistance and sometimes even to contact surface melting and thus to connector damage. In this study, the mechanical behaviour and heat evolution of a commercial power connector used in the automotive industry was undertaken. Using an experimental set-up, the mechanical insertion force, the temperature and the resistance evolution were measured. To quantify these parameters at the contact zone, two numerical modellings, using the finite element software Ansys, were employed to give the change of the insertion force during several insertion-extraction cycles and to solve the differential equations for heat transfer in a transitory mode. Adapted values of thermal and electrical contact conductances introduced into the numerical modelling, resulted in good values for both contact resistance and contact temperature, which were verified by experiments.

Semi-permanent electrical contacts are found throughout the whole range of instrumentation and control product, connecting devices. The reliability of this kind of connector - designed for long lifetime service is highly dependant on mechanical and corrosion degradations. In this domain, corrosion is avoided by using a thick gold layer while the major cause of connector ageing remains the contact spring degradation (relaxation, loss of force…) leading subsequently to a change of contact resistance. In this paper, a non intrusive (laser) technique is used to view and measure both the deflection and its associated force. These techniques and tools are applied both to new springs and to degraded springs. In the absence of an analytical model due to the complex geometry of the spring, a numerical finite element model has been developed to compute the deflection versus force. Linear deflections are observed for various stiffnesses for different springs located in the same connector. The main explanation for this change is the variation of the embedding length of the spring inside the connector. In addition the stiffness dependence due to ageing by thermal cycling is discussed.

Studies of connectors for electric and electronic automotive systems have been and still are being pursued. The main criterion for the electrical contact reliability is to minimize the connector insertion force, which mainly depends on the contact force determined by the mechanical design. A non-intrusive technique for contact force determination by deflection measurement of the contact spring during insertion and extraction phase using a laser device has been developed. We have access to the following insertion parameters during the insertion stroke: contact deflection /spl delta/ which yields the contact force F/sub c/, insertion force F/sub i/ and contact resistance R/sub c/. Regarding the results for real connectors, an experimental model of a connector based on a cylindrical pin crossed with a cylindrical spring, is proposed in This work. With this simple setup, we have made an analytical model, which permits analysis of the influence of each parameter (width, spring radius etc). Based on analysis of the influence of the spring width and of the gap, this study offers the possibility of optimizing the design of such connectors for use in the automotive industry.