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Strange gearbox tooth pattern

Strange gearbox tooth pattern

Strange gearbox tooth pattern

Hello Guys,
in attachments you found some photo about strange gearbox tooth pattern found. Before the inspection i made some vibration measurement on it discovered this:4

-1XM in axial 13,5 mm/s
-2XM in radial 16 mm/s
-1XGMF 2mm/s

THis machine is forming roll in a papaer machine (MOTOR-PENDULUM GEAR-CILYNDER).
All of your consideration about tooth pattern will be helpfull.


RE: Strange gearbox tooth pattern

I have seen this pattern (especially last phot) with greater wear spots at end of teeth caused by a gear natural frequency (confirmed by impact test) where the vibration mode was a wobble of the larger (bull) gear.


RE: Strange gearbox tooth pattern

Your Welcome for Thanks or feedback in advance!


RE: Strange gearbox tooth pattern


Based on the contact pattern, i would recommend you to check for the axial play in the bearing. I hope the gear is mounted on a set of taper roller bearings. Kindly ensure that the pre-loading in the taper roller bearings are fine. I hope that this should solve the problem. Further, I feel that there has been an initiation of micro pitting in the gear flank. Kindly check for the viscosity of the oil and also for the presence of any abrasive/metal particles in the lubrication oil.



RE: Strange gearbox tooth pattern

it appears from the photos the helical pinion has excessive wear,
some suggestions
attach a magnetic base with a dial indicator on ground surface, and look for excessive runout.
could be a worn bearing , or miss alignment.
a rebuild of this gear box is required, the pinion gear is worn.
the vibration is the teeth interfering causing excessive wear.

a full failure analysis will be required, a qualified engineer or technician or both, will have to
tear down the box and document and take pictures of each component.
document were and how the failure occurred.

RE: Strange gearbox tooth pattern

Apparently the OP is not interested, since it was posted Feb-11.


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