A Novel Testing Approach to Validating Automotive Lubricant Performance in Fretting Conditions Dr. Jason T. Galary*
The reliability of components such as actuators, bearings, and electrical terminals in automotive applications is a critical factor related to warranty requirements and customer safety. Despite its importance, it can be very difficult and expensive to test component reliability. Historically, it has also been very difficult to produce repeatable data with bench testing, even with large sample sets, to provide useful results. This has driven the use of computer simulation modeling, which reduces testing time and cost with a much smaller computational impact, although component level or full application testing is still required by OEM’s and Tier 1 suppliers . This paper presents a new benchtop apparatus, the multi-terminal fretter, to test and validate components like actuators and electrical terminals for their ability to protect against fretting conditions. This new methodology allows for various frequency and amplitude conditions to be tested to generate life probability curves and understand the improvements made by lubrication. In the present study, the multiterminal tester was applied to electrical terminals. It provided meaningful data and demonstrated its value for testing applications subjected to fretting conditions and showing how various lubricants help improve their reliability and extend their lives. KEY WORDS: Fretting, Electrical Contact, Connector Lubricant, Grease, Corrosion *Nye Lubricants, Inc., Fairhaven, MA Introduction and Background There has been a sharp increase in the volume of electrical and electronic components used in commercial, industrial, consumer, and military applications over the last decade. The life of these components is directly related to the reliability of electrical contacts. Along with reliability, safety is also of the highest concern for automotive applications, especially with the rise of hybrid and battery electric vehicles (BEV). Together, reliability and safety directly impact the perceived quality of automobiles, which tie to their quality and warranty aspects. With the global trend moving towards adding additional electronic controls to automotive applications, or complete conversion as is the case with electrical and hybrid vehicles (EHV), there can be more than 400 connectors with over 3,000 individual electrical terminals in an automobile [1]. At the heart of these applications are the electrical terminals and contacts, which are subjected to oxidation, humidity, vibration, and fretting. The phenomenon of fretting wear refers to small amplitude, relatively high frequency oscillatory slip motion between two bodies in contact. In automotive applications, vibrations or thermal cycling can cause fretting due to very small oscillations that range from fractions of a micrometer up to about 100 µm. For electrical terminals and other components, this amount of relative movement between mated components leads to several types of surface damage that result in fretting corrosion and wear. In fretting wear, the top layer of material is removed due to pure mechanical wear.
- 14 VOLUME 83, NUMBER 2
