A vehicle garage contacted Off-Highway Powertrain Services (OHP Services) because vibrations were occurring on passenger transport vehicles at certain engine speeds.
OHP Services recommended a vibration measurement to find the reasons for the vibrations which could be felt through the passenger seats and to identify opportunities to improve the vehicles’ powertrain. For this purpose the vehicle had been equipped with vibration sensors which recorded data during a test ride (on the street).
The measurement values demonstrated that the main vibrations are increasing at a speed range around 80km/h. Further investigations confirmed resonance in a center bearing of the cardan shaft which was installed 6 mm too high. Due to the wrong alignment the acceleration forces became stronger creating vibration. To reduce this effect the center bearing was lowered and the powertrain rebalanced.
In addition the vibration data indicated a small imbalance of the retarder disc. To protect the bearings and the complete powertrain lifetime, balancing was performed onsite.
The changes have been verified by a second vibration check and the customer is very satisfied with the results.