Method and apparatus for testing cyclically operated mechanical members for defects

• US 4,213,346 A
• Filed: 10/06/1978
• Issued: 07/22/1980
• Est. Priority Date: 12/05/1977
• Status: Expired due to Term

• Current Assignee: Alexandr A. Mischenkov, Anatoly M. Zaznobin, Gennady F. Masalov, Sergei V. Polovnikov
• Original Assignee: Alexandr A. Mischenkov, Anatoly M. Zaznobin, Gennady F. Masalov, Sergei V. Polovnikov
• Inventors: Zaznobin, Anatoly M., Mischenkov, Alexandr A., Masalov, Gennady F., Polovnikov, Sergei V.
• Primary Examiner(s): Ciarlante, Anthony V.
• Application Number:
  US05/949,376
• Time in Patent Office: 655 Days
• Field of Search: 73/660, 73/593
• US Class Current: 73/660
• CPC Class Codes: G01M 13/028 Acoustic or vibration analysis
• CPC Class Codes: G01M 13/045 Acoustic or vibration analysis
• CPC Class Codes: G01N 2291/2696 Wheels, Gears, Bearings

Abstract

A method for testing cyclically operated mechanical members for defects comprises the steps as follows: a frequency range of at least two wideband electrical signals corresponding to the defects of the test member is selected; the modulus and phase of the resultant electrical signals is determined and the magnitude is accumulated using the value of the phase of that signal within a given number of rotational cycles of the test member; defect locations are determined using the maximal accumulated magnitudes of the resultant electrical signal and their corresponding phases. An apparatus to realize the disclosed method comprises at least two vibration pickups adapted to sense the vibration of the test member and coupled to the inputs of adjustable pass band filters which are operated to select a frequency range corresponding to the defects of the test member. The outputs of the filters are coupled to the inputs of a resultant electrical signal magnitude computing unit which is coupled to the input of a summing analyzer. The latter has another input coupled to a resultant electrical signal phase detector. There are also two position pickups adapted to determined the position of the test member and coupled to the resultant electrical signal phase detector.

Claims

1. A method for testing cyclically operated mechanical members for defects, comprising the steps of

converting vibration signals produced by a cyclically operated mechanical member under test to at least two wideband electrical signals;

extracting from the wideband electrical signals electrical signals having a frequency range corresponding to defects of the test member;

converting the angular position of the test member to a position electrical signal;

determining the magnitude and phase of a resultant electrical signal using two selected wideband electrical signals;

accumulating the magnitude of the resultant electrical signal using the values of the phase of that signal within a given number of rotational cycles of the test member; and

determining the location of the defects of the test member using the maximal accumulated magnitudes of the resultant electrical signal and their corresponding phases.

2. A method as claimed in claim 1, further comprising the steps of

subtracting, after the determination of the magnitude and the phase of the resultant electrical signal, the value of the electrical signal characteristic of the angular position of the test member from the value of the electrical signal characteristic of the phase of the resultant electrical signal;

and

accumulating the magnitudes of the resultant electrical signal using the values of the difference of the electrical signals characteristic of the phase of the resultant electrical signal and the angular position of the test member.

3. A device for testing cyclically operated mechanical members for defects, said device comprising

at least two vibration pickups adapted to sense the vibration of a cyclically operated mechanical member under test, said vibration pickups having operating axes arranged at right angle to each other, mounted on said test member, and each having an output;

a plurality of adjustable band pass filters adapted to select a frequency range corresponding to the defects of the test member, each having inputs coupled to said outputs of said vibration pickups and each having an output;

a resultant electrical signal modulus computing unit having a plurality of inputs equal in number to said adjustable band pass filters and coupled to said outputs of said adjustable band pass filters, said computing unit having three outputs;

a summing analyzer having two inputs and an output, the first input of said summing analyzer being coupled to a first output of said three outputs of said resultant electrical signal modulus computing unit;

a registering unit having an input coupled to said output of said summing analyzer;

at least two position pickups adapted to determine the position of the test member, said position pickups being mounted on the test member and each having an output; and

a resultant electrical signal phase detector having a plurality of inputs, two of said inputs of said signal phase detector being coupled to two outputs of said resultant electrical signal modulus computing unit, said signal phase detector having an output coupled to said second input of said summing analyzer,

respective inputs of said resultant electrical signal phase detector being coupled to said outputs of said position pickups.