Device for detecting damage on rotators

• US 4,007,630 A
• Filed: 07/09/1975
• Issued: 02/15/1977
• Est. Priority Date: 07/12/1974
• Status: Expired due to Term

• Current Assignee: Nippon Seiko Kabushiki Kaisha (NSK Limited)
• Original Assignee: Nippon Seiko Kabushiki Kaisha (NSK Limited)
• Inventors: Noda, Banda
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/594,251
• Time in Patent Office: 587 Days
• Field of Search: 73/67, 73/71.2, 73/71.4
• US Class Current: 73/593
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis
• CPC Class Codes: G01N 2291/2696 Wheels, Gears, Bearings
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/449 Statistical methods not provided for in G01N29/4409, e.g. averaging, smoothing and interpolation

Abstract

There is disclosed a device for detecting damage on rotators or rotary bodies such as for example ball bearings having rolling elements. A mechanical vibration or sound produced periodically due to damage on the rotator when it is rotated is converted into an electric signal. In order to identify such damage on the rotator by utilizing the periodic characteristic of said electric signal, a peak detector is provided for detecting a peak value of said electric signal, holding the detected peak value for a fixed period, and being reset to a base level by a reset signal.

Claims

1. A device for detecting damage on a rotator by converting into electric signals the mechanical oscillation or sound produced when said rotator is rotated, and evaluating the amplitude of the electric signals originating from the presence of damage on the rotator manifested as an impulsive oscillation having a period dependent upon the rate of rotation of said rotator, said device comprising:

a peak detector for detecting the peak value of said electric signals and holding that value as a DC level,

a reset pulse generator for generating reset pulses having a predetermined pulse repetition rate to reset said peak detector at a predetermined time interval, the repetition rate of the reset pulses being predetermined so that said peak detector repeats at least twice the cycle of peak detecting, holding and resetting during one period of said impulsive oscillation, and

means for deriving an output signal from said peak detector.

2. A device in accordance with claim 1, further comprising a band-pass filter for eliminating the DC output component from said peak detector output signal and extracting the AC component alone, whereby the damage, if any, on the rotator is detected according to the presence or absence of said AC component.

3. A device for detecting damage on a rotator by converting into electric signals the mechanical oscillation or sound produced when said rotator is rotated, and evaluating the amplitude of the electric signals originating from the presence of damage on the rotator manifested as an impulsive oscillation having a period dependent upon the rate of rotation of said rotator, said device comprising:

a peak detector for detecting the peak value of said electric signals and holding that value as a DC level,

a reset pulse generator for generating reset pulses having a predetermined pulse repetition rate to reset said peak detector at a predetermined time interval, the repetition rate of the reset pulses being predetermined so that the period of the cycle of peak detecting, holding and resetting is several times longer than the period of said impulsive oscillation,

means for deriving an output signal from said peak detector, and

an integration circuit for smoothing said output signal, whereby the presence and degree of the damage on the rotator are detected according to the amount of a DC output voltage of said integration circuit.