Online detection method for ball bearing contact angle of aero-engine

The invention discloses an online detection method for the ball bearing contact angle of an aero-engine, and the method comprises the steps: installing a magnetoelectric vibration speed sensor on theinstallation edge of a casing before the aero-engine operates; connecting the output of the sensor to a vibration signal analyzer, meanwhile, connecting a rotating speed signal, and setting the vibration signal analyzer to be in an order tracking analysis mode to test and analyze the case vibration signal of the aero-engine in a small rotating speed state; when characteristic frequencies appear onthe two sides of the high-voltage rotor, extracting the frequencies; and analyzing the rolling bearing fault type corresponding to the characteristic frequencies, and calculating the actual contact angle of the ball bearing through a frequency formula. The method has the advantages that the actual contact angle of the ball bearing is calculated through the small-rotating-speed state characteristic frequency and used for d