Bevel gear inspection 2

[hexhamallstar]

Hi all,

I'm currently having a problem with bevel gear inspection. Basically I am working on a right angle drive unit, of which I have a number of benchmark gear pairs that I would like to base my design on. The benchmark gears are all precision forged straight bevel gears and I do not have the drawing data for them.

Ultimately, I would like to work out the loading that these gears were designed for however I am having problems with getting them inspected as (or so I've been told by the companies i've contacted) the tooth form is near impossible to inspect without having the nominal data to hand. I'm guessing that most places will only be able to measure things such as tip diameters and landwidth etc (physical dimensions that can be measured) and won't be able to provide me with a pitch diameter or a means of calculating the pitch diameter.

My question then is this; are there any dimensions that I can feasibly get inspected that I can use to give me a good idea of the strength of these gears? These kinds of gears are used extensively in the automotive industry and so somebody must have come up with a method of rating competitors gears?

Best regards and thanks in advance for any replies,

Phil

 

[gearcutter]

It's almost impossible to accurately reverse engineer gear data from a sample bevel set without knowing the machine setup which the operator used to originally make the set. This is why it's never a good idea to try and mix & match pairs as each set will be slightly different if those sets are made using different setups.
Having said that; if all you are trying to conduct is a load rating analysis, then it's not overly important to know the exact profile data........especially if it's only a straight bevel set. Things start getting a little more difficult if we were talking about spiral geometries.

Take your gears to a reputable gear shop that specialises in the manufacture of bevel gears and I'm sure that they'll be able to help you come up with the basic data. The most important dimensions that you'll need are the mounting distance, pitch, pressure angle and also the angle of the input/output shafts.

What part of the vehicle are these gears being used on?


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[hexhamallstar]

Hi gearcutter,

Thanks for your reply and sorry for the delay, these gears are the final drive gears however i've also got some bevel gears from the inside of a differential mechanism that I would like to find the load capacity for.

So far the companies that I have approached have told me that they can't help without the gear data. Are you saying that i need to know the pitch diameter or is that meant to be pitch angle? I also had one company tell me that they can't help because of the fact that the final drive gears are forged rather than machined. We are looking at getting the design module of Gleason's CAGE software, do you have any experience with this programme?

How would I use the dimensions you have listed above to perform a load rating analysis?

Cheers,

Phil

 

[gearcutter]

"How would I use the dimensions you have listed above to perform a load rating analysis?"

Phil; if you are unable to answer this question yourself then I would highly recommend that you engage the services of a gear design consultant.
If you want to try to do it yourself then the AGMA has a bevel gear program that you can purchase.
They can also supply you with the relevant load rating standards for bevel gears. -

http://www.agma.org/

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181