Criteria for defining face gear quality 1

[INFANTI]

In my company, we supply gears and pinions with AGMA 6 face quality. It's been proven to be a very reliable standard since it's been used for 25 years in our equipments.
We have a client demanding AGMA 12 and I wanted to convince him it's not appropriate and much more expensive.

The gears and pinions work at a very low rotation (+- 0,05 rpm), in oil bath, and diameter vary from 42'' to 100''.

AGMA 390.03 shows the AGMA numbers, but there is no reference on how to apply them.

Question: How exactly do I know what AGMA number should I use for each application? Is there a rotation reference? Diametral pitch? Kind of equipment?

I've seen a table showing indicated AGMA numbers for rotation ranges, but there was no Standard reference.

Items 2 and 38 of the attached is an example.

I appreciate any help

 

[geesamand]

I do not believe AGMA makes recommendations regarding quality level vs. intended service.

Would your customer be amenable to other final checks like noise level or vibration limits?

David

 

[israelkk]

In some AGMA design handbooks such as AGMA 170.01-1976 Standard Design Guide for Vehicle Spur and Helical Gears, on page 25 there is a table that gives derating factors as a function of the AGMA accuracy number for different types of vehicles (Truck, Passenger cars and Off-highway vehicles). You should look for AGMA design guide that is relevant to the type of use/machine you have and it may have a similar information.

 

[dinjin]

AGMA 6 is often specified for commercial large gears.
I would spec out an AGMA 8 for the pinion as it will
wear in the gear and see more revolutions. There used
to be recommendations of gear quality for applications.
AGMA 12 is unusual for a commercial gear unless it is
for a telescope requiring very accurate tracking.
If the customer is willing to pay the high cost of the
AGMA 12 give it to him. I have not heard the term
AGMA XX defined as face quality before. I am fairly
certain that the old quality standards were only 4
and they were letters A thru D and defined Total
Composite Error values. AGMA 12 would require grinding
and definitely applies to precision applications
or for long life or high speed conditions. You might want to ask the customer why he wants an AGMA 12. Is it some spec
requirement that he is bound to?

 

[gearcutter]

It's not unusual to see AGMA class 12 gearing in a modern industrial or commercial gearbox.
I have OEM drawings going back to the early 1990s specifying class 12 for gearing in an Italian rolling mill gearbox. Pitch is 12 module and PCD on one of the bull gears is around 1 meter.


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

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