SBIR-STTR Award

The overall objectives of the proposed program are to develop non-invasive, wear resistant, light weight sensors and instrumentation for in-situ monitoring of temperature and vapor pressure for space and land based anti-friction rolling element bearings. This will be achieved by depositing thin films of appropriate materials on the raceways of rolling element bearings using RF-sputter coating and patterning the coatings into micro-sensors using photolithography. RF-sputter coating allows deposition of coatings at temperatures less than 180 degrees C. Maintaining low temperatures is essential in assuring that the hardened bearing steel is not tempered. Zirconium and nichrome will be used for development of micro-temperature and pressure sensors respectively. In Phase I micro-temperature and pressure sensors will be fabricated and evaluated in a bearing simulator rig allowing rolling and sliding conditions. Sliding increases surface heating and shear stress and tests the durability of micro-sensors. These micro-sensors can be used with minor modifications to monitor lubricated contacts in aerospace and automotive applications (e.g. gears, journal bearings, seals, etc.). A thermal balance formed using a thermocouple junction both as a sensor and heating block will be used to measure vapor pressure. The vapor pressure and quartz micro-balance sensors will be used to monitor lubricant losses.

Phase II of this program, built on the research results and technology developed during Phase I will take three thrusts. First, an attitude-control wheel (ACW) bearing simulator will be procured from one of the ACW manufacturers (AlliedSignal Aerospace or Teldix GmbH) or designed and developed by Innovative Design and Technology LTD. This rig will permit evaluation of different sensing technologies under realistic bearing load, speed, atmosphere, lubricant introduction, and ambient temperature conditions. Second, the remotely-powered telemeter design evaluated during Phase I will be implemented in the form of a bearing retainer instrumented for ball-pocket temperature measurement via mass-balanced telemeter. Capacitive susceptors will remotely power the telemeter and receive its output signal. Finally, the process used to manufacture thin-film in-situ micro-sensors will be transitioned from laboratory analogs to production prototypes on bearing raceways. This type of micro-sensor will be used to rapidly indicate the operating condition of the instrumented ACW bearing. ACW simulator testing will be used to verify the utility, mechanical durability and noninvasiveness of in-situ micro-sensors. Each of these tasks is critical and necessary to advance the project from Phase I research to Phase II product development.

Keywords:
Elastohydrodynamic Contact Pressure Sensor Rolling Element Bearing Temperature Sensor Thin Film Sensor