Abnormality diagnosis device and abnormality diagnosis method for ball screw

An abnormality diagnosis device for a ball screw, the abnormality diagnosis device comprising:

• a vibration sensor that detects vibration during an operation of the ball screw;
• a filter processing unit that executes, on a vibration signal acquired by the vibration sensor, filtering processing for extracting a frequency band including at least a characteristic frequency corresponding to a specific frequency of the ball screw;
• an envelope processing unit that executes envelope processing for the vibration signal after the filtering processing;
• a frequency analysis processing unit that executes fast Fourier transform processing on a time domain signal after the envelope processing;
• a peak hold averaging processing unit to which frequency domain data after frequency analysis processing is sequentially input for each sampling period defined by an inverse of a frequency resolution in the fast Fourier transform processing, the peak hold averaging processing unit configured to execute peak hold averaging processing for the frequency domain data acquired for each sampling period;
• and
• an abnormality determination unit that performs abnormality determination for the ball screw based on the frequency domain data after the peak hold averaging processing.

An abnormality diagnosis method for a ball screw, the abnormality diagnosis method comprising:

• a first step of detecting vibration during an operation of the ball screw;
• a second step of executing, on a vibration signal acquired in the first step, filtering processing of extracting a frequency band including at least a characteristic frequency corresponding to a specific frequency of the ball screw;
• a third step of executing envelope processing for the vibration signal after the filtering processing;
• a fourth step of executing fast Fourier transform processing on a time domain signal after the envelope processing;
• a fifth step of sequentially inputting frequency domain data after frequency analysis processing for each sampling period defined by an inverse of a frequency resolution in the fast Fourier transform processing, and executing peak hold averaging processing for the frequency domain data acquired for each sampling period;
• and
• a sixth step of performing abnormality determination for the ball screw based on the frequency domain data after the peak hold averaging processing.