GBS Gearbox Services international brand of Schaaf- en Boorwerk Rotterdam B.V.
Emergency Hotline
text voor google

Inspection and replacement of CMD JC 26 JUMBOREX Split Torque

Inspection and replacement of pinion of gearbox of brand CMD

  • CMD
  • JC 26 JUMBOREX Split Torque
  • Input=___ rpm / ____ KW
  • CMD JC26 JUMBOREX Split-Torque Gearbox repair
  • Gearbox repair in Pakistan

Scope of work:

We performed an inspection and repair on a gearbox CMD JC 26 JUMBOREX Split Torque.
GBS Gearbox Services was approached by a customer in the mining industry in Pakistan, they experienced elevated vibrations on their CMD Gearbox. Repair of this gearbox was required after finding damage in the second stage pinion on the left side of the gearbox. Inspection revealed that an incorrect contact pattern was the root cause of the damage. We modified the new pinion by reverse engineering and made a modified helix angle of the teeth, which solved the contact pattern problem that caused overloading of the teeth and finally resulted in cracks on the teeth.

One of our service engineers traveled to Pakistan, after arriving on-site we removed the input shaft and both 2nd stage pinions from the CMD gearbox.
Then we removed all the rolling element bearings and replaced them with new bearings that had been heated in an oil bath of 110° C before installing them on the shafts. After assembling the new bearings and couplings on all the shafts (3x) we finished assembly and could now start installing the shafts back into the gearbox. The alignment of the shafts and the gears had to be done very precisely, to prevent any vibrations that could damage the gearbox.

With all the pieces in place we closed the top cover of the gearbox and started the limited test run at 25% load, this was due to power shortage.

After the test run we collected all the data needed and went back to the Netherlands to begin writing the report.

Main accomplishments : Vibrations levels during startup reduced from 10,5 mm/s to <2 mm/s. Vibrations levels during operation reduced to less than 0,5 mm/s. Restored the reliability of the gearbox.

The conversion operations consists of:

  • Replacement of the left side 2nd stage pinion
  • Replacement of the rolling element bearings of input shaft and both 2nd stage pinions
  • Provide short and long term recommendations

contact us

Location - date:

Pakistan - October - December 2012

Other types of same brand: