Hi,
I am looking at the premature wear of a worm and gear. I have attached a couple of pics. My initial thoughts are backlash and oil issues. The backlash shim also failed. Any advice? 
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Overload of worm/brass gear and/or wrong lubricant
https://www.machinerylubricati...Read/1080/worm-gears
http://uigearlab.com/wp-conten...of-Gear-Failures.pdf
Dave
Hi Dave,
many thanks for that. The helical gear shows signs of advanced wear also. Is this related to the loading and lubricant problem?
kind regards
Jim
Sorry, not the expert on gears, based on the images you are showing....the lubrication was present and everything is nice and clean, without seeing the worn areas very closely....I would assume there was not EP additive (extreme pressure) in the oil or the gear was overloaded
Dave
Hi Dave,
Thank you for your reply. The oil used in the gearbox has EP additives in it.
Kind regards,
Jim.
Is this a first time event, new gearbox, or what? Past history could be important.
EP additives that contain sulfur can cause Severe damage to the broze gear. High temperatures aggravate the condition even further.
Double check that the lubricant you are using meets the recommendations of the gear manufacturer. I would also closely watch the lubricant condition by testing the oil, perhaps on a quarterly basis until you get the failure resolved.
There are clear indications that both worm and worm wheel have undergone wear.
Reasons:
Worm is normally unusual to get worn out. It may be due to wrong bronze material. It could be hard and caused abrasion.
Clear indication of the gear box having been subjected to overload. Or there is a misalignment of the worm and worm wheel. Both the worm wheel teeth centre and worm teeth centre not matching.
You should go for a higher dp/module set of worm and worm wheel, which should satisfy your load requirement
Almost certainly wrong lubricant. This worm gear is a sliding contact application, with a softer bronze pinion. EP additives are only for rolling/sliding contact where both contacts are ferrous gears. EP doesn’t provide protection in this contact and can contribute to bronze corrosion and loss. Only oils with compounding agents or PAG synthetics have the necessary polarity and lubricity to maintain an effective sliding contact film to protect the surfaces. AGMA ISO 18792-A19 provides guidance for selection of appropriate lubricants for gear drives, including worm gears. Selection of lubricants for gears and other industrial components is taught in the MLT/MLA-1 training class: http://store.mrgcorp.com/mla-mlt-level-i-training/