DETECTION OF DISTRIBUTED DEFECTS IN GEAR ASSEMBLIES
First Claim
1. A system for detecting a distributed defect in one gear of a pair of meshing rotating gears comprising a vibration sensor coupled to the pair of gears for sensing vibrations thereof and converting said vibrations into an electrical signal, means, including a bandpass filter coupled to said vibration sensor, for deriving from said electrical signal a second amplitude modulated signal having a period equal to the meshing period of said gears and a modulation envelope with a period having an integral relation to the period of rotation of said one gear, means for demodulating said second signal and producing a third signal indicative of the magnitude of amplitude modulation, and output means responsive to said third signal for indicating a distributed gear defect.
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Accused Products
Abstract
A distributed defect in one of a pair of meshing gears produces a modulation in amplitude of the component of the vibration signal which has the same repetition rate as the meshing frequency of the gears. The modulation has a frequency corresponding to the period of rotation of the gear with the distributed effect or a submultiple thereof. Detection of the modulation provides an indication of the existence, character and extent of the defect.
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Citations
5 Claims
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1. A system for detecting a distributed defect in one gear of a pair of meshing rotating gears comprising a vibration sensor coupled to the pair of gears for sensing vibrations thereof and converting said vibrations into an electrical signal, means, including a bandpass filter coupled to said vibration sensor, for deriving from said electrical signal a second amplitude modulated signal having a period equal to the meshing period of said gears and a modulation envelope with a period having an integral relation to the period of rotation of said one gear, means for demodulating said second signal and producing a third signal indicative of the magnitude of amplitude modulation, and output means responsive to said third signal for indicating a distributed gear defect.
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2. A system according to claim 1 wherein said means for deriving said second modulated signal includes signal enhancement means for enhancing the portion of said electrical signal passed by said bandpass filter.
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3. A system according to claim 1 wherein said means for demodulating said second signal and producing said third signal comprises a peak detector circuit, a demodulator circuit, and a difference circuit for comparing the outputs of said peak detector and demodulator circuits to thereby produce said third signal.
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4. A system according to claim 1 wherein said means for deriving said second modulated signal includes signal enhancement means for enhancing the portion of said electrical signal passed by said bandpass filter, and said means for demodulating said second signal and producing said third signal comprises a peak detector circuit, a demodulator circuit, a difference circuit for subtracting the outputs of said peak detector and demodulator circuits, and a divider circuit for dividing the outputs of said demodulator and difference circuits to thereby produce said third signal corresponding to the percentage of modulation.
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5. A system according to claim 1 wherein said output means is responsive to a predetermined percentage modulation of said third signal.
Specification