Inspection and repair of JSW gearbox

A client from Belgium came to us with this JSW gear unit. We reviewed the unit and did a total overhaul. After the overhaul was done, we did a lot of testing and prepared the gear unit to be shipped back to this client.

Conclusions

The condition of the gearbox is considered to be unacceptable.

The rolling elements and outer ring of bearing number 15 (radial bearing left output shaft) moved in axial direction (towards the extruder). When comparing the endoscopic images to the images taken on april 12, the outer-ring seemed to have moved slightly back into the bore.

This could be an indication that the fit between bearing bore of the bush is outside of specification. Damage or wear of the bush, might creature metal shavings/small particles.

The situation is highly unpredictable and it is therefore impossible to determine the estimated lifetime of the bearing/gearbox. Failure of the bearing however, will cause substantial damage to the gearbox.

It is recommended to:

- Provide a clear drawing with a part list of the gearbox;

- Open the gearbox; o Inspect why the outer ring and rolling elements of bearing number 15 moved in axial direction; o Measure bore diameter of the bush, fitted around bearing 15; o Change at least bearing 15; o Possibly replace bush, fitted around bearing 15, depending on the condition of the bore.

- Perform a visual inspection and oil analyses annually to monitor the condition of the gearbox