How to calculate "Test Radius" for cylinder spur gear ? 2

[luckwz]

We need to define the 'test radius'on 2D prints to the supplier.I read the AGMA-2000-A88,It is define the 'maximum and minimum test distance, Cd.'But I still do not know how to calculate the 'test radius',Could you pls help me? Thanks.

 

[dinjin]

What is the context for test radius.
Is it a functional radius that must be maintained on the master pinion or cutter in order to check the tif diameter of the parts?

 

[israelkk]

Maximum and minimum testing radius are measured with master gears in tight mesh on a double flank testing machine.

measured gear testing radius = center distance - master gear pitch radius

 

[luckwz]

it is spur gear,Mn=0.64,Z1=15,Z2=57,pressure angle is 20?center distance is 23.8.profile shift Z1=0.5891,profile shift Z2=0.7318,on the 2D print define 'test radius for Z1 is 3.356 (0/-0.131) and test radius for Z2 is 15.885 (0/-0.139)' I do not know how to calculate the two test radius and the tolerance. I know it will used to qualify the tooth thickness and maybe important.could you pls let me know the calculate details,thanks.

 

[dinjin]

These values are below the base circle radii and they are probably wrong.

test radius for
Z2 is 15.885 (0/-0.139)
base radius is 17.13999

Z1 is 3.356 (0/-0.131
base radius is 4.51052

 

[luckwz]

dinjin,
Thank you so much for your reply.from the quantitatively,I believe you are right.But could you pls do me a favour let me know the details of how to calculate it?I can find KissSoft has the function to calculate master gear,but I only have a limit kissSoft license,it is can not active. or maybe you can send email to me'vivific@163.com',thanks a lot.

 

[dinjin]

israelkk (Aerospace) 9 Oct 11 12:56
Maximum and minimum testing radius are measured with master gears in tight mesh on a double flank testing machine.

measured gear testing radius = center distance - master gear pitch radius

This makes sense to me.
Do you have a double flank testing machine or are you sending them out to be checked?

 

[tpederzani]

(I know this is an older thread, so this reply is for those that stumble on it later.)

Take a look at AGMA 2002-B88, Section 8.4 "Composite Test Action Measurement". Some of the information was previously in AGMA 370.01 [from 1973], but that spec shows how to calculate the maximum, but does some hand-waving to determine the minimum. AGMA 2002, however, shows how to calculate the maximum and the minimum (the latter of which takes into account tooth thickness tolerance and TCE).

 

[mfgenggear]

see this previous post

http://www.eng-tips.com/viewthread.cfm?qid=276367

Mfgenggear

 

[tpederzani]

I would have actually responded to that thread, but it was closed. As long as someone has a real master gear handy (to get its CTT and test diameter), there should be no barrier to back-calculating the maximum/minimum tooth thickness using the formulas in AGMA 2002-B88. The answers are subtly different than ones with the formula you provided. Plus, the AGMA 2002-B88 formulas take TCE into account.

That way, the range on CTT should be reduced to compensate for the TCE. So a gear with the max CTT and max TCE would still pass TPR. (Precision Gearing by Michalec has a small section about the ambiguity in correlating MOW and TR measurements on page 567 thru 569). [Figure attached]

(On another note, when I used the numbers in that thread and the appropriate TCE [.0014] for AGMA 9 (i.e. from 390.02), I got the same CTT for the max and min... I don't think that gear has allowance for the tooth thickness to vary.)

 

[mfgenggear]

tpederzani

yes It was understood that the TCE & CTT are inclusive with the Test Diameter with a know master gear.

I do not have the AGMA 2002-B88 could you please post the formula
of the latest.

Thanks for pointing out the latest

Mfgenggear

 

[gearcutter]

luckwz,

You keep coming on this forum asking for help with using KissSoft.
You talk about having a limited licence.
KISS soft’s basic gear package will work all this out for you (as it has with other questions you've asked but you just haven't seen it) so I don't understand why you keep coming on here asking these questions.
The only thing that I can see is that you are using an illegal copy of the program and therefore are not able to receive any technical help from KissSoft.
If you are a professional in the gear industry and give advice to your customers, then I would highly recommend that you purchase a legal copy of the software and learn how to use it correctly with the program's designer's help rather than coming on this forum and cheating.
As a professional, the questions you are asking are basic and you should know the answers to them yourself.
If you are having difficulties then I would highly recommend that you engage the help of a professional gear design consultant.


Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

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

 

[tpederzani]

mfgenggear,

Here are the appropriate formulas from AGMA 2002. It also contains a 2nd formula theta_3, but I haven't used it yet. AGMA 2002 is a really good reference to have on your shelf -- it also covers the dimension over pins/MOW.