Matsumoto, K., Koga, H., Suzuki, S., and Mihara, Y., "Measurement of Oil Film Pressure on Running Continuously Variable Transmission Pulley Part 1: Measurement Using Micro Data Logger System and Thin-Film Sensor," SAE Int. J. Passeng. Cars - Mech. Syst. 7(1):307-311, 2014, doi:10.4271/2014-01-1732.
In order to reduce friction and predict wear of the sliding part, it is important to determine the oil film thickness of particular area. A sensor or similar device must be attached to the sliding surface to detect the oil film thickness. However, a sensor could not be attached, due to the lack of space on contact surface, and moreover there was no method to secure the sensor on contact surface at that time. A several-micrometer-thin-film sensor was installed on a sliding surface to attempt measurement, but since the sensor was attached on a contact surface, wear occurred immediately and data was unable to be obtained.To accomplish above issue, we developed a protective layer with excellent wear-resistance that successfully extended the measurement time by protecting the thin-film sensor. In order to measure pressure during driving, we provided a PVD (Physical Vapor Deposition) thin-film sensor of several micrometers on the drive transmission surface of a CVT (Continuously Variable Transmission) pulley. In addition, we were able to obtain data rapidly from parts during driving by independently developing an ultra-micro data logger (A/D conversion board + memory) and mounting it to mobile parts. In this paper, we describe the issues that must be solved in relation to the measurement method.