Rotational Speed and Temperature Monitoring of Ball Bearing Using Tribocharge Sensor

Abstract

The tribocharge sensor to monitor the rotational speed and the temperature of ball bearing was fabricated and we studied the basic feasibility this tribocharge sensor. The tribocharge sensor was built up by the segmented electrode on rotor, the segmented electrode on stator. Electrode material is Cu of 35µm thick and the material of base film is polyimide of 25µm thick. This sensor was attached on the side on the ball bearing. This tribocharge sensor outputted the pulse voltage from the stator electrode. The output voltage was proportional to the rotational speed of ball bearing. The generated electric power was 0.2µW at 2000 rpm, however, the electric power of 20µW was expected by the reduction of PFTE film thickness. On the other hand, the temperature of ball bearing was estimated by the envelope of negative voltage from the tribocharge sensor, and the estimated temperature approximately agreed with the temperature estimated by the friction force.