Inspection and repair project of FLENDER B2-DH-14-C gearbox

Scope of work:

We performed an inspection and revision on FLENDER gearbox B2-DH-14-C.

We performed a total review and full overhaul on this FLENDER B2-DH-14-C gearbox from one of our clients in Netherlands. After a good test run, we transfered the FLENDER B2-DH-14-C gear unit back to the client.

Both gearboxes are in good condition.

Both gearboxes show no significant damage on all teeth, only slight scratches. Both gearboxes show no significant damage on all bearings. Only slight impressions, scratches and running marks were observed on the outer ring of different bearings. The bearings of the input shaft could not be inspected. The scratches and impressions are caused by hard particles (metal) in the oil. A large amount of carbon deposits has been observed in the drum. This stop can cause an imbalance force on the input shaft.

The axial adjustment of the output shaft is slightly outside the recommended clearance from Flender. The axial clearance for drive 1 was 0.73 mm and for drive 2 0.65 mm. Flender recommends an axial clearance of at least 0.20 mm and at most 0.50 mm for the output shaft. This deviation in adjustment cannot cause a temperature increase.

The axial play of the input shaft and the first between shaft is measured at 0.00 mm for both cabinets. According to Flender, the input shaft should also have 0.00 mm. According to Flender, the first intermediate shaft should have a pre-stress of 0.14 mm to 0.24 mm. Unfortunately, pre-tensioning cannot be measured without dismantling the covers. A bias can cause additional temperature development.

It is recommended to:

- install a scrapper in the brake drum to reduce the carbon deposits
- install the gearboxes; - if there is still an imbalance on the input shaft, to assess this with the help of residual imbalance (more info ISO 1940-1: 2003)
- to properly measure the temperature difference of both cabinets during start-up. Measure all lower temperatures every 15 minutes until they stabilize
- have a visual inspection with vibration measurement and alignment check performed every year
- carry out the maintenance plan as described in the manual