Abnormal noise detector for use in the inspection of gear units
First Claim
1. An abnormal noise detector for the inspection of gear units having gears, two of which mesh and produce noise of a normal fundamental frequency which is a function of the rate at which the teeth of said two gears mesh, comprising:
- a microphone placed in the vicinity of a gear unit to be tested; and
detecting means responsive to an electrical output signal from said microphone for continuously detecting momentary variations in the amplitude of the component of said signal having a prescribed frequency which is an integral multiple of said normal fundamental frequency.
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Accused Products
Abstract
An abnormal noise detector for detecting abnormal noises resulting from a marred tooth surface in a gear of a gear unit is disclosed. A first embodiment of a detector comprises a microphone placed in the vicinity of a gear unit to be tested, a bandpass filter for filtering the output of the microphone so as to pass only an integral multiple of the fundamental frequency of noise due to meshing of the gears of the gear unit, a rectifier for rectifying the filtered output from the bandpass filter, a differentiator for differentiating with respect to time the DC output from the rectifier, a waveform shaper for shaping the output from the differentiator into pulses suitable for counting, and a pulse counter for quantifying the pulses in the output from the waveform shaper. A second embodiment comprises a microphone, a digital frequency analyzer, and a data monitoring computer responsive to the digital frequency analyzer for monitoring the output thereof.
19 Citations
3 Claims
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1. An abnormal noise detector for the inspection of gear units having gears, two of which mesh and produce noise of a normal fundamental frequency which is a function of the rate at which the teeth of said two gears mesh, comprising:
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a microphone placed in the vicinity of a gear unit to be tested; and detecting means responsive to an electrical output signal from said microphone for continuously detecting momentary variations in the amplitude of the component of said signal having a prescribed frequency which is an integral multiple of said normal fundamental frequency. - View Dependent Claims (2, 3)
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Specification