How can wear and damage in rolling and sliding bearings be detected using ultrasound?

Mechanical processes in bearings generate structure-borne sound that propagates through the machine and bearing housing. Changes in this structure-borne sound can indicate changes in the condition of the bearing.

Using the SONAPHONE with a structure-borne sound sensor, these signals can be detected, made audible, and evaluated.

What is evaluated during the measurement?

The assessment can include:

• the measured ultrasonic level,
• the level curve over time,
• the spectrogram,
• the audible ultrasonic signal,
• changes compared with previous measurements.

If the ultrasonic signals of a bearing change compared with its previous condition, this may indicate wear, malfunction, or changed operating conditions.

Which sensors are used?

The BS20 and BS40 structure-borne sound sensors are available for machine and bearing inspection.

The BS20 is coupled directly to the test point using a waveguide and is suitable, among other applications, for monitoring wear and malfunction in rolling and sliding bearings.

The BS40 can be coupled to the machine using a magnetic base or screw connection, for example, and is particularly suitable for recurring or longer-term condition measurements.

Why are comparative measurements important?

A single ultrasonic level does not provide a universally valid assessment of every bearing. Bearing design, speed, load, lubrication, and the measurement point all influence the measured signal.

Monitoring the development of a defined measurement point over time is therefore particularly useful.

AssetExpert and the SONAPHONE DataSuite can be used to organize measurement points and inspection routes and to evaluate historical measurements, thresholds, and trends.

For comparable results, measurements should be performed under similar operating conditions and using the same measurement point, sensor, and coupling method wherever possible.