Vibration Sensing technique for monitoring condition of ball/rolling bearings and gearboxes

The paper introduces some details of new hand-held sensor with extended vibration frequency measurement range till 20 kHz. The sensor provides new diagnostics capabilities especially for rolling/ball bearings and gearboxes. It is related to discovering the unknown before behavior of one point contact metal to metal. It is found that traditional transfer function is incorrectly described after resonance frequency response of the contact. Theoretically and by experiments is shown that frequency response of such contact after resonance is linear in logarithmic axis and linearly dependence of applied to that contact forces. The measurement range of stick sensors traditionally supposed to lay from several Hz to 1 kHz and its resonance usually lay at the 2-3 kHz. So, such sensors widely recommended using to approximately 1 kHz. Discovered linearity's provide possibility electronically compensate decreasing of frequency response after resonance and measuring vibration accurately after resonance in the over 10 times wider range about 4 to 20 kHz. The new extended frequency response of stick sensor required two things to be implemented to work properly: electronics compensation which up signal approximately on 15 dB/octave in a range of 5-20 kHz and force sensor for measuring the applied forces all the time. Then new stick sensor response presented as the ratio of vibration frequency compensated signal and the forces signal in real time. Such stick sensor works in two ranges: in traditional 10 Hz 1 kHz and extended 4-20 kHz which allow somebody measuring regular vibration as well as controlling bearing and gearboxes by hand-held devises w/o any surface preparation.